Analysis of the impact of Smallholder Irrigation Schemes on the choice of rural livelihood strategy and household food security in Eastern Cape
- Authors: Christian, Mzuyanda
- Date: 2017
- Subjects: Irrigation -- South Africa -- Eastern Cape Farms, Small -- South Africa -- Eastern Cape Food security -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4813 , vital:28526
- Description: Since the end of Apartheid, the South African government has invested substantially in smallholder irrigation schemes, particularly in the former homeland areas. One of the primary goals for establishment of these schemes was to solve food security problems. Sadly, these efforts have not produced the desired results, and poverty has deepened. The question that can be asked is: What is it that makes South African smallholder agricultural sector seemingly impervious to the interventions that government has made in targeting smallholder farmers since the dawn of democracy in 1994? In order to address such a question, a set of structured questionnaires was used to interview 100 smallholder irrigators and 100 non-irrigators using multistage stratified random sampling technique in the Amatole, Chris Hani and OR Tambo District municipalities. Demographic and socio-economic characteristics of smallholder irrigators and non-irrigators around Qamata, Pendu, Tyhefu, Merelles and Ntshongweni irrigation schemes were measured using descriptive statistics. Profitability between the two groups was measured using gross margin analysis (GM). The Probit model was used to determine the factors that affect smallholder farmer‘s choice of participation in irrigation schemes. The impact of irrigation participation on yields, crop sales and food security was estimated using the propensity score matching (PSM) technique. The impact of irrigation participation of smallholder farmer‘s choice of livelihood strategy was estimated using the multinomial regression model. The results showed that male respondents were dominant with a representation of 63 percent and average mean household size of 4 persons with the household head having spent at least 7 years at school. Farming was found to be the major (64 percent) occupation in the study area with an average income of R2 944.52 per cropping season. Both irrigating and non-irrigating smallholder farmers in the study area used improved, fertilizer and tractor for production. Overall, smallholder farmers spent 30.9 percent of their household income on food with irrigators‘food spending lower than those of non-irrigators. The gross margin analysis suggests that the irrigated farmers were in a better position to afford enough food in order to satisfy their household requirement. Findings from the Probit regression and Propensity Score Matching are consistent across the methods, indicating that irrigation participation has a positive influence on crop yields, income and consumption expenditure. Probit regression further showed that age, quality of land, access to credit, access to market, distance to the scheme and membership of another society/association have a positive impact on access and use of irrigation and are significant at p < 0.05 percent level. The Propensity Score Matching using Nearest Neighbour and Kernel Matching Methods of the outcome variables, total farm income and food consumption patterns, shows a positive and statistically significant result at p < 0.05 percent level. The nearest neighbour matching method shows that irrigators received higher farm income R2044.01 than non-irrigating farmers R622.12. The Average Treatment Effect on total food expenditure was negative both in the case of NNM and KM algorithms, indicating that participation in irrigation can decrease the expenditure levels on food from R933.30 to R926.70. This could be due to the fact that irrigating farmers produced enough for home consumption than non-irrigators. The multinomial regression model shows that irrigation participation influences smallholder farmers choice of livelihood strategy and these variables were statistically significant at p < 0.05 percent level. These results provide insights to address the question as to the appropriate development path for transition from homestead to irrigation. Continued support to smallholder farmers in the forms of funding, extension services and improved technologies is certainly needed to enhance food security.
- Full Text:
- Date Issued: 2017
- Authors: Christian, Mzuyanda
- Date: 2017
- Subjects: Irrigation -- South Africa -- Eastern Cape Farms, Small -- South Africa -- Eastern Cape Food security -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4813 , vital:28526
- Description: Since the end of Apartheid, the South African government has invested substantially in smallholder irrigation schemes, particularly in the former homeland areas. One of the primary goals for establishment of these schemes was to solve food security problems. Sadly, these efforts have not produced the desired results, and poverty has deepened. The question that can be asked is: What is it that makes South African smallholder agricultural sector seemingly impervious to the interventions that government has made in targeting smallholder farmers since the dawn of democracy in 1994? In order to address such a question, a set of structured questionnaires was used to interview 100 smallholder irrigators and 100 non-irrigators using multistage stratified random sampling technique in the Amatole, Chris Hani and OR Tambo District municipalities. Demographic and socio-economic characteristics of smallholder irrigators and non-irrigators around Qamata, Pendu, Tyhefu, Merelles and Ntshongweni irrigation schemes were measured using descriptive statistics. Profitability between the two groups was measured using gross margin analysis (GM). The Probit model was used to determine the factors that affect smallholder farmer‘s choice of participation in irrigation schemes. The impact of irrigation participation on yields, crop sales and food security was estimated using the propensity score matching (PSM) technique. The impact of irrigation participation of smallholder farmer‘s choice of livelihood strategy was estimated using the multinomial regression model. The results showed that male respondents were dominant with a representation of 63 percent and average mean household size of 4 persons with the household head having spent at least 7 years at school. Farming was found to be the major (64 percent) occupation in the study area with an average income of R2 944.52 per cropping season. Both irrigating and non-irrigating smallholder farmers in the study area used improved, fertilizer and tractor for production. Overall, smallholder farmers spent 30.9 percent of their household income on food with irrigators‘food spending lower than those of non-irrigators. The gross margin analysis suggests that the irrigated farmers were in a better position to afford enough food in order to satisfy their household requirement. Findings from the Probit regression and Propensity Score Matching are consistent across the methods, indicating that irrigation participation has a positive influence on crop yields, income and consumption expenditure. Probit regression further showed that age, quality of land, access to credit, access to market, distance to the scheme and membership of another society/association have a positive impact on access and use of irrigation and are significant at p < 0.05 percent level. The Propensity Score Matching using Nearest Neighbour and Kernel Matching Methods of the outcome variables, total farm income and food consumption patterns, shows a positive and statistically significant result at p < 0.05 percent level. The nearest neighbour matching method shows that irrigators received higher farm income R2044.01 than non-irrigating farmers R622.12. The Average Treatment Effect on total food expenditure was negative both in the case of NNM and KM algorithms, indicating that participation in irrigation can decrease the expenditure levels on food from R933.30 to R926.70. This could be due to the fact that irrigating farmers produced enough for home consumption than non-irrigators. The multinomial regression model shows that irrigation participation influences smallholder farmers choice of livelihood strategy and these variables were statistically significant at p < 0.05 percent level. These results provide insights to address the question as to the appropriate development path for transition from homestead to irrigation. Continued support to smallholder farmers in the forms of funding, extension services and improved technologies is certainly needed to enhance food security.
- Full Text:
- Date Issued: 2017
Appraisal of experimental performance and modelling of an on-farm dairy milk bulk cooler: Fort Hare Dairy Trust, South Africa
- Authors: Mhundwa, Russel
- Date: 2017
- Subjects: Milk -- Cooling Milk -- Cooling -- Equipment and supplies Milk tanks -- Specifications
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/4671 , vital:28487
- Description: South Africa contributes approximately 0.5 percent to the total world milk demand and is the third largest producer of fresh cow milk in Africa after Sudan and Kenya. In comparison to any other enterprise, the cost of milk production is influenced by numerous factors, that in turn affect the profitability of the farm enterprise; however one of such factors is high electricity cost. In this regard, there is need for efficient operation of the milk processing plant at all stages and at the same time maximising on product quality and minimising on the cost of production including energy. At the dairy farm, milk handling mainly commences as the milk leaves the cow udder at 35°C–37°C and must be cooled rapidly to a storage temperature of 4°C in a bid to stop microbial activity. The cooling of the milk can be done directly by the bulk milk cooler (BMC) from 37°C to the required storage temperature of 4°C or it can be done successively through pre-cooling. The process of pre-cooling involves the use of a heat exchanger where in most instances the plate heat exchanger (PHE) is used as the pre-cooler (PC) thereby leading to energy savings in a dairy facility. Cooling of milk involves significant amount of energy and it could account for about 20 percent of the total energy consumed on a farm. The aim of the research was to develop mathematical models that could be used to predict the electrical energy performance and capture the cooling saving of an on-farm direct expansion bulk milk cooler (DXBMC) during the milk cooling process. Accordingly, data acquisition system (DAS) was designed and built to accurately measure the power consumption of the BMC, temperature of raw milk, room temperature, temperature of cold water, relative humidity and ambient temperature. The volume of milk produced per day was extracted from the daily records on the farm. In addition, the temperature sensors were connected to a four channel HOBO data loggers which were configured to log at every five-minutes interval. The results were analysed and the mathematical models were developed using MATLAB. The statistical Toolbox in MATLAB was used to rank the predictors according to their weight of importance using the ReliefF Algorithm test. The results showed that on average, the daily electrical energy consumed by the BMC at the two milking times was higher during the peak period (127.82 kWh and 93.86 kWh) than the off-peak period (48.31 kWh and 43.23 kWh). On average, the electricity used for cooling of milk on the dairy farm was 17.06 kWh/m3 of milk. The average monthly electricity used per cow on the farm was 8.03 kWh/cow which translated to an average of 0.26 kWh/cow/day The average specific energy consumption of the cooling system per litre of milk cooled was 0.02 kWh/L and was almost constant throughout the whole period of monitoring. Furthermore, the BMC was able to cool 57.33 L/kWh during the off-peak period which increased by 7.7 percent to 62.13 L/kWh during the peak period. Furthermore, mathematical models represented as multiple linear regression (MLR) models were built and developed using the experimental data. The developed mathematical models had good agreement with the experimental data as evidenced by the correlation coefficients of 0.922 and 0.8995 along with 0.935 and 0.930. The ReliefF Algorithm test revealed that the volume of milk was the principal contributor to the energy consumption of the BMC for both the morning (AM) and afternoon (PM) milking period. The Relative Prediction Error (RPE) was used to evaluate the suitability of the developed models. In this light, the AM off-peak model had RPE of 18.54 percent while the PM off-peak model had 14.42 percent. In addition, the AM peak and PM peak models had RPE of 19.23 percent and 18.95 percent respectively. This suggested that the MLR models for the off-peak and peak milking periods (both AM and PM) had acceptable prediction accuracy since the RPE values were between 10 percent and 20 percent. The findings from the experimental study showed that the coefficient of performance (COP) of the AM milking period was higher (2.20) than that of the PM milking period of the BMC (1.93). Increase in the milk volume led to an increase in the COP such that the peak period with higher milk volumes recorded a high COP increase of 12.61 percent and 19.81 percent for the AM and PM milking periods respectively.
- Full Text:
- Date Issued: 2017
- Authors: Mhundwa, Russel
- Date: 2017
- Subjects: Milk -- Cooling Milk -- Cooling -- Equipment and supplies Milk tanks -- Specifications
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/4671 , vital:28487
- Description: South Africa contributes approximately 0.5 percent to the total world milk demand and is the third largest producer of fresh cow milk in Africa after Sudan and Kenya. In comparison to any other enterprise, the cost of milk production is influenced by numerous factors, that in turn affect the profitability of the farm enterprise; however one of such factors is high electricity cost. In this regard, there is need for efficient operation of the milk processing plant at all stages and at the same time maximising on product quality and minimising on the cost of production including energy. At the dairy farm, milk handling mainly commences as the milk leaves the cow udder at 35°C–37°C and must be cooled rapidly to a storage temperature of 4°C in a bid to stop microbial activity. The cooling of the milk can be done directly by the bulk milk cooler (BMC) from 37°C to the required storage temperature of 4°C or it can be done successively through pre-cooling. The process of pre-cooling involves the use of a heat exchanger where in most instances the plate heat exchanger (PHE) is used as the pre-cooler (PC) thereby leading to energy savings in a dairy facility. Cooling of milk involves significant amount of energy and it could account for about 20 percent of the total energy consumed on a farm. The aim of the research was to develop mathematical models that could be used to predict the electrical energy performance and capture the cooling saving of an on-farm direct expansion bulk milk cooler (DXBMC) during the milk cooling process. Accordingly, data acquisition system (DAS) was designed and built to accurately measure the power consumption of the BMC, temperature of raw milk, room temperature, temperature of cold water, relative humidity and ambient temperature. The volume of milk produced per day was extracted from the daily records on the farm. In addition, the temperature sensors were connected to a four channel HOBO data loggers which were configured to log at every five-minutes interval. The results were analysed and the mathematical models were developed using MATLAB. The statistical Toolbox in MATLAB was used to rank the predictors according to their weight of importance using the ReliefF Algorithm test. The results showed that on average, the daily electrical energy consumed by the BMC at the two milking times was higher during the peak period (127.82 kWh and 93.86 kWh) than the off-peak period (48.31 kWh and 43.23 kWh). On average, the electricity used for cooling of milk on the dairy farm was 17.06 kWh/m3 of milk. The average monthly electricity used per cow on the farm was 8.03 kWh/cow which translated to an average of 0.26 kWh/cow/day The average specific energy consumption of the cooling system per litre of milk cooled was 0.02 kWh/L and was almost constant throughout the whole period of monitoring. Furthermore, the BMC was able to cool 57.33 L/kWh during the off-peak period which increased by 7.7 percent to 62.13 L/kWh during the peak period. Furthermore, mathematical models represented as multiple linear regression (MLR) models were built and developed using the experimental data. The developed mathematical models had good agreement with the experimental data as evidenced by the correlation coefficients of 0.922 and 0.8995 along with 0.935 and 0.930. The ReliefF Algorithm test revealed that the volume of milk was the principal contributor to the energy consumption of the BMC for both the morning (AM) and afternoon (PM) milking period. The Relative Prediction Error (RPE) was used to evaluate the suitability of the developed models. In this light, the AM off-peak model had RPE of 18.54 percent while the PM off-peak model had 14.42 percent. In addition, the AM peak and PM peak models had RPE of 19.23 percent and 18.95 percent respectively. This suggested that the MLR models for the off-peak and peak milking periods (both AM and PM) had acceptable prediction accuracy since the RPE values were between 10 percent and 20 percent. The findings from the experimental study showed that the coefficient of performance (COP) of the AM milking period was higher (2.20) than that of the PM milking period of the BMC (1.93). Increase in the milk volume led to an increase in the COP such that the peak period with higher milk volumes recorded a high COP increase of 12.61 percent and 19.81 percent for the AM and PM milking periods respectively.
- Full Text:
- Date Issued: 2017
Elicitation of risk preferences of smallholder irrigation farmers in the Eastern Cape Province of South Africa
- Authors: Modjadji, Mathlo Itumeleng
- Date: 2017
- Subjects: Irrigation farming -- South Africa -- Eastern Cape Risk-return relationships -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4846 , vital:28534
- Description: Although several studies have investigated commercial farmers’ risk preferences, there is still lack of information on the risk attitudes and risk preferences of smallholder farmers in South Africa. Risks associated with the adoption of new agricultural technology need to be explored in order to address the transition from homestead food gardening to smallholder irrigated farming. This study seeks to understand risk perception of smallholder irrigation farmers by linking constraints to commercialisation, adoption of new agricultural technologies and risk preferences of smallholder farmers in the Eastern Cape Province of South Africa. The overall objective of this research is to determine risk preference patterns and attitudes that influence the transition from homestead food gardening to irrigated farming of smallholder farming systems in the Eastern Cape province of South Africa. Specifically the study was to pursue the following objectives: (i) describe the demographic and socio-economic characteristics of smallholder farmers; (ii) describe existing farming systems among smallholder farmers in the study area; (iii) analyse the adoption of new agricultural technology by smallholder irrigation farmers; (iv) assess the risk perception of smallholder irrigation farmers and elicit farmers risk preferences, and (v) empirically analyse farmers sources of risk and risk management strategies. The outcome of this will inform policy formulation that have implications for technology adoption, increase smallholders capacity to bear risk and enable government and other role players have a clear understanding of smallholder farmers decisions. A total of 101 respondents were surveyed, consisting of 38 smallholder farmers and 63 homestead food gardeners in the Eastern Cape. Questionnaires were used to record household activities, socio-economic and institutional data as well as household demographics through personal interviews. The ordered probit model was applied due to the ordered nature of the dependent variable. The analysis was used to empirically analyse the determinants of farmers ‘risk preference status. The ordered probit model successfully estimated the significant variables associated with the farmer‘s adoption decisions. These were the farmer‘s age, household size, land size, locational setting, risk attitude, number of livestock (goats and chicken) and asset ownership. Homestead food gardeners were less risk averse that the smallholder farmers. Farmers who reside in the sub-wards Binfield and Battlefield were more likely to take risk than those who reside in Melani. This suggests the presence of local synergies in adoption which raises the question about the extent to which ignoring these influences biases policy conclusions. The negative correlation between land size and adoption implies that smaller farms appear to have greater propensity for adoption of new agricultural technology. This finding is supported by several studies reviewed in the literature that allude to the fact that homestead food gardeners tend to be smaller than smallholder farmers. By means of the Principal Component Analysis (PCA), seven principal components (PCs) that explained 66.13 percent of the variation were extracted. According to the loadings, the factors 1 to 7 can best be described as ‘financial and incentives index’, ‘input-output index’, ‘crop production index’, ‘labour bottleneck index’, ‘lack of production information index’, ‘lack of market opportunity index’, and ‘input availability index’ respectively. In general, price, production and financial risks were perceived as the most important sources of risk. Socio economic factors having a significant effect on the various sources of risk are age, gender, education, location, information access and risk taking ability. The most important traditional risk management strategies used by the surveyed smallholder farmers in Eastern Cape are crop diversification, precautionary savings and participating in social network. The findings are consistent with economic theory which postulates that in the absence of insurance markets, poor farm households tend to be risk averse and are reluctant to participate in farm investment decisions that are uncertain or involve higher risk.
- Full Text:
- Date Issued: 2017
- Authors: Modjadji, Mathlo Itumeleng
- Date: 2017
- Subjects: Irrigation farming -- South Africa -- Eastern Cape Risk-return relationships -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4846 , vital:28534
- Description: Although several studies have investigated commercial farmers’ risk preferences, there is still lack of information on the risk attitudes and risk preferences of smallholder farmers in South Africa. Risks associated with the adoption of new agricultural technology need to be explored in order to address the transition from homestead food gardening to smallholder irrigated farming. This study seeks to understand risk perception of smallholder irrigation farmers by linking constraints to commercialisation, adoption of new agricultural technologies and risk preferences of smallholder farmers in the Eastern Cape Province of South Africa. The overall objective of this research is to determine risk preference patterns and attitudes that influence the transition from homestead food gardening to irrigated farming of smallholder farming systems in the Eastern Cape province of South Africa. Specifically the study was to pursue the following objectives: (i) describe the demographic and socio-economic characteristics of smallholder farmers; (ii) describe existing farming systems among smallholder farmers in the study area; (iii) analyse the adoption of new agricultural technology by smallholder irrigation farmers; (iv) assess the risk perception of smallholder irrigation farmers and elicit farmers risk preferences, and (v) empirically analyse farmers sources of risk and risk management strategies. The outcome of this will inform policy formulation that have implications for technology adoption, increase smallholders capacity to bear risk and enable government and other role players have a clear understanding of smallholder farmers decisions. A total of 101 respondents were surveyed, consisting of 38 smallholder farmers and 63 homestead food gardeners in the Eastern Cape. Questionnaires were used to record household activities, socio-economic and institutional data as well as household demographics through personal interviews. The ordered probit model was applied due to the ordered nature of the dependent variable. The analysis was used to empirically analyse the determinants of farmers ‘risk preference status. The ordered probit model successfully estimated the significant variables associated with the farmer‘s adoption decisions. These were the farmer‘s age, household size, land size, locational setting, risk attitude, number of livestock (goats and chicken) and asset ownership. Homestead food gardeners were less risk averse that the smallholder farmers. Farmers who reside in the sub-wards Binfield and Battlefield were more likely to take risk than those who reside in Melani. This suggests the presence of local synergies in adoption which raises the question about the extent to which ignoring these influences biases policy conclusions. The negative correlation between land size and adoption implies that smaller farms appear to have greater propensity for adoption of new agricultural technology. This finding is supported by several studies reviewed in the literature that allude to the fact that homestead food gardeners tend to be smaller than smallholder farmers. By means of the Principal Component Analysis (PCA), seven principal components (PCs) that explained 66.13 percent of the variation were extracted. According to the loadings, the factors 1 to 7 can best be described as ‘financial and incentives index’, ‘input-output index’, ‘crop production index’, ‘labour bottleneck index’, ‘lack of production information index’, ‘lack of market opportunity index’, and ‘input availability index’ respectively. In general, price, production and financial risks were perceived as the most important sources of risk. Socio economic factors having a significant effect on the various sources of risk are age, gender, education, location, information access and risk taking ability. The most important traditional risk management strategies used by the surveyed smallholder farmers in Eastern Cape are crop diversification, precautionary savings and participating in social network. The findings are consistent with economic theory which postulates that in the absence of insurance markets, poor farm households tend to be risk averse and are reluctant to participate in farm investment decisions that are uncertain or involve higher risk.
- Full Text:
- Date Issued: 2017
Evaluation of some pharmaceutical and personal care products and pesticide residues in selected wastewater treatment plants and receiving watersheds in Eastern Cape, South Africa
- Ademoyegun, Olufemi Temitope
- Authors: Ademoyegun, Olufemi Temitope
- Date: 2017
- Subjects: Emerging contaminants in water -- South Africa -- Eastern Cape Water treatment plants -- Waste disposal -- South Africa -- Eastern Cape Organic compounds -- Environmental aspects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/2922 , vital:28138
- Description: Emerging organic contaminants (EOCs) have been the focus of global environmental research for over three decades. EOCs have caused widespread concern due to their extensive use. As EOCs were designed to correct, enhance or protect a specific physiological, their target effects in humans and/or farm stocks are relatively well known and documented. However, there is limited knowledge about their unintended effects in the environment. To address the occurrence, distribution and fate of EOCs in the environment, efficient and reliable analytical methods are needed. The relatively low concentration, high polarity, and thermal lability of some EOCs, together with their interaction with complex environmental matrices, make their analysis challenging. Sample preparation followed by GC or HPLC separation and mass spectrometry (MS) detection has become the standard approach for evaluating EOCs in environmental samples. Physicochemical properties of EOCs range from highly water-soluble (hydrophylic) to highly water-insoluble (hydrophobic). Two groups of these EOCs were considered for study in this work. Pharmaceutical and personal care products (PPCPs) were comprehensively studied in five wastewater treatment plants and their receiving watersheds in Amathole districts in Eastern C ape, South Africa. PPCPs have been widely reported in wastewater influents, effluents, receiving rivers and biosolids, but reports of their occurrence in all these matrixes have been limited by the difficulty of analysis. Therefore, a comprehensive validation of methods was carried out on the influents, effluents, sludge and soil from the irrigated golf course where the effluent of one of the study sites was being used for over three decades now for irrigation. In all, thirteen PPCPs from five therapeutic groups were selected for study in this work because of their administering rate and availability of analytical instrument. Good limit of detection (LOD) and limit of quantification (LOQ) were achieved for the method used. The LOD for the aqueous Three different technologies were employed for the treatment of wastewater in the five selected wastewater treatment plants (WWTPs) and study was carried out to evaluate their ability to eliminate the selected compounds from the influents to the effluents using statistical analysis (ANOVA) at p<0.05 on the percentage removal rate across the three plants. The results had shown eight of the compounds having no significant difference among the treatment operations, whereas the remaining five compounds varied significantly among the treatment technologies under investigation. Principal component analysis was performed on the concentration of PPCPs, their removal rate and also on the physicochemical and treatment operation parameters. Hydraulic retention time (HRT) had correlation coefficient, r = 0.90 with the concentration of PPCPs and removal rates. Furthermore, occurrences, seasonal variation, mean concentration distribution pattern of the compounds, and temporal evaluation of the mean concentration of the pharmaceutical compounds in the five WWTPs during one year of sampling were considered. The results revealed that five products which were diclofenac, ibuprofen, paracetamol, triclosan and diethyl toluamide (DDET) were predominant among the PPCPs in all the WWTPs. The removal efficiency was highest in caffeine with 96 percent, and the lowest was obtained with carbamazepine (4 percent). Risk quotient of the concentration of PPCPs in the effluents and receiving waters was determined to assess their chronic toxicity at three trophic levels: fish, algae and matrixes studied ranged from 0.01 μg/L to 0.25 μg/L, and the LOQ from 0.02 μg/L to 0.78 μg/L. In the solid matrixes, LOD varied from 0.01 ng/g to 0.65 ng/g, and the LOQ between 0.08 ng/g and 5.17 ng/g. Better recovery efficiency was obtained with this mixture of solvents, acetone: dichloromethane (1:1), for the recovery of the five therapeutic groups in the solid matrixes using ultrasonication- assisted techniques. The results show percentage recovery values ranging from 68.8 percent to 107.5 percent diaphian. According to the environmental risk assessment results, ibuprofen and triclosan were found to be the most critical compounds due to their high risk quotient values. These findings will, therefore, help in the future evaluation of the efficiency of different treatment technologies in the removal of various PPCPs from the wastewater and their sustainable management in the aquatic resources in Eastern Cape, South Africa. For the lipophilic organochlorine pesticides (OCPs), the limits of detection (LODs) of the tested congeners varied from 0.04 ng/g (α-BHC) to 0.49 ng/g (endosulfan sulfate) and the limits of quantification ranging from 0.22 ng/g (aldrin) to 2.17 ng/g (δ-BHC).
- Full Text:
- Date Issued: 2017
- Authors: Ademoyegun, Olufemi Temitope
- Date: 2017
- Subjects: Emerging contaminants in water -- South Africa -- Eastern Cape Water treatment plants -- Waste disposal -- South Africa -- Eastern Cape Organic compounds -- Environmental aspects -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/2922 , vital:28138
- Description: Emerging organic contaminants (EOCs) have been the focus of global environmental research for over three decades. EOCs have caused widespread concern due to their extensive use. As EOCs were designed to correct, enhance or protect a specific physiological, their target effects in humans and/or farm stocks are relatively well known and documented. However, there is limited knowledge about their unintended effects in the environment. To address the occurrence, distribution and fate of EOCs in the environment, efficient and reliable analytical methods are needed. The relatively low concentration, high polarity, and thermal lability of some EOCs, together with their interaction with complex environmental matrices, make their analysis challenging. Sample preparation followed by GC or HPLC separation and mass spectrometry (MS) detection has become the standard approach for evaluating EOCs in environmental samples. Physicochemical properties of EOCs range from highly water-soluble (hydrophylic) to highly water-insoluble (hydrophobic). Two groups of these EOCs were considered for study in this work. Pharmaceutical and personal care products (PPCPs) were comprehensively studied in five wastewater treatment plants and their receiving watersheds in Amathole districts in Eastern C ape, South Africa. PPCPs have been widely reported in wastewater influents, effluents, receiving rivers and biosolids, but reports of their occurrence in all these matrixes have been limited by the difficulty of analysis. Therefore, a comprehensive validation of methods was carried out on the influents, effluents, sludge and soil from the irrigated golf course where the effluent of one of the study sites was being used for over three decades now for irrigation. In all, thirteen PPCPs from five therapeutic groups were selected for study in this work because of their administering rate and availability of analytical instrument. Good limit of detection (LOD) and limit of quantification (LOQ) were achieved for the method used. The LOD for the aqueous Three different technologies were employed for the treatment of wastewater in the five selected wastewater treatment plants (WWTPs) and study was carried out to evaluate their ability to eliminate the selected compounds from the influents to the effluents using statistical analysis (ANOVA) at p<0.05 on the percentage removal rate across the three plants. The results had shown eight of the compounds having no significant difference among the treatment operations, whereas the remaining five compounds varied significantly among the treatment technologies under investigation. Principal component analysis was performed on the concentration of PPCPs, their removal rate and also on the physicochemical and treatment operation parameters. Hydraulic retention time (HRT) had correlation coefficient, r = 0.90 with the concentration of PPCPs and removal rates. Furthermore, occurrences, seasonal variation, mean concentration distribution pattern of the compounds, and temporal evaluation of the mean concentration of the pharmaceutical compounds in the five WWTPs during one year of sampling were considered. The results revealed that five products which were diclofenac, ibuprofen, paracetamol, triclosan and diethyl toluamide (DDET) were predominant among the PPCPs in all the WWTPs. The removal efficiency was highest in caffeine with 96 percent, and the lowest was obtained with carbamazepine (4 percent). Risk quotient of the concentration of PPCPs in the effluents and receiving waters was determined to assess their chronic toxicity at three trophic levels: fish, algae and matrixes studied ranged from 0.01 μg/L to 0.25 μg/L, and the LOQ from 0.02 μg/L to 0.78 μg/L. In the solid matrixes, LOD varied from 0.01 ng/g to 0.65 ng/g, and the LOQ between 0.08 ng/g and 5.17 ng/g. Better recovery efficiency was obtained with this mixture of solvents, acetone: dichloromethane (1:1), for the recovery of the five therapeutic groups in the solid matrixes using ultrasonication- assisted techniques. The results show percentage recovery values ranging from 68.8 percent to 107.5 percent diaphian. According to the environmental risk assessment results, ibuprofen and triclosan were found to be the most critical compounds due to their high risk quotient values. These findings will, therefore, help in the future evaluation of the efficiency of different treatment technologies in the removal of various PPCPs from the wastewater and their sustainable management in the aquatic resources in Eastern Cape, South Africa. For the lipophilic organochlorine pesticides (OCPs), the limits of detection (LODs) of the tested congeners varied from 0.04 ng/g (α-BHC) to 0.49 ng/g (endosulfan sulfate) and the limits of quantification ranging from 0.22 ng/g (aldrin) to 2.17 ng/g (δ-BHC).
- Full Text:
- Date Issued: 2017
Litter quality effects on soil stabiltiy and erodibility in the Ntabelanga Area, Eastern Cape, South Africa
- Authors: Parwada, Cosmas
- Date: 2017
- Subjects: Soil erosion Soil management -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4824 , vital:28531
- Description: Soil organic matter (SOM) plays a primary role in aggregation and stabilization of soils, hence reducing their susceptibility to erosion. In South Africa (SA), most soils have low (< 4 percent) soil organic matte (SOM) contents, making them susceptible to soil erosion. Little is known about SOM quality effects in soil stabilization in the SA context, it is therefore difficult to advocate specific organic matter sources in order to stabilize a particular soil. This study evaluated effects of different litter quality sources (Vachellia karoo (sweet thorn) leaf litter and Zea mays (maize) stover) on soil aggregate stabilization at a soil micro-level (soil aggregate), guided by the following specific objectives; (i) to characterize soil properties that influence the erodibility of soils in the Ntabelanga area, Eastern Cape (EC) Province, SA (ii) to assess fractionation of organic carbon during decomposition of different litter sources (iii) to determine rate of soil macroaggregate re-formation under different litter amendments (iv) to determine the influence of different litter quality on splash soil erosion and (v) to delineate the Ntabelanga area into different soil erosion sensitivity zones. Soil samples collected from a proposed Ntabelanga dam site, EC Province, SA, were characterized for factors influencing erodibility. Soil physical and chemical properties were analyzed, soil erodibility (K-factor) estimated using SOC content and surface properties and soil loss rates by splashing determined under rainfall simulations at 360 mm h-1 rainfall intensity. Soil loss was then correlated with the chemical and physical soil properties. SOC showed significant (P< 0.05) inverse relationship with soil loss. Soils samples were bulked to seven composite samples according to major soil horizons (orthic A, melanic A, pedocutanic B, red apedal B, saprolite, G horizon and prismacutanic B) in the areas of soil associations, macroaggregate (> 0.250 mm) were removed by passing through a 0.250 mm sieve. The remaining soil microaggregates (< 0.250 mm) were then mixed with high quality Vachellia karoo leaf litter (C/N = 23.8) and low quality Zea mays stover (C/N = 37.4) and incubated at 23oC for 30 weeks. Jars were arranged as a 7 × 3 factorial laid in completely randomized design (CRD) with three replicates. Data was repeatedly measured at 1, 3, 8, 14, 23 and 30 weeks after incubation: to determine the stabilization of SOM by fractionating the soil particulate organic matter (POM), rate of soil macroaggregate re-formation and influence of litter quality on splash soil erosion along a decomposition continuum. Free light fractions (Free LF), coarse particulate organic matter (CoPOM) and fine particulate organic matter (FiPOM) within macroaggregates (> 250 μm) decreased exponentially from week 1 to 30 and were significantly (p < 0.05) influenced by litter quality × soil horizon × time interactions. A similar trend for FiPOM fractions in macroaggregates was observed in the 53-250 μm microaggregates (p < 0.05). The greatest influence on changes in POM fractions occurred within the first 3 weeks of incorporation. Both V. karroo leaf litter and Z. mays stover significantly stabilized the macroaggregates within the first 3 weeks after incubation. Cumulative macroaggregates yields, mean weight diameter (MWD), percentage water stable aggregates (%WSA) and whole soil stability index (WSSI) in litter amended soils increased up to week 8 of incubation and thereafter gradually declined in all soils. An increase in macroaggregation resulted in increased MWD, WSSI values and large and small aggregates distribution. Aggregation was significantly higher in soils with higher clay content than sand content, suggesting that soil texture was highly influential in litter decomposition. Rate of litter decomposition was influenced by soil type × time interactions which determined extent and macroaggregation dynamics along a decomposition continuum. The amount of splashed sediments was determined from each soil horizon at 360 mm h-1 simulated rainfall intensity applied as either single 8minute rainstorm (SR) or 4 × 2minute intermittent rainstorms (IR) separated by a 72 h drying period. Results showed a reduction in splashed sediments under IR and SR storms in litter-amended soils during the first 8 weeks of incubation with gradual increase thereafter. More sediments were splashed under IR than SR and litter quality had no influence on splashed sediments per soil horizon. Soil horizons profile with more clay than sand particles enhanced the litter effects on the soil resistance against detachment. The amount of SOC loss was influenced by primary particle size distribution and initial SOC content of the soil. Rainfall pattern and the initial SOC content were the main factors by which different soils influenced SOC loss. More rainstorm patterns should be investigated on these soils.
- Full Text:
- Date Issued: 2017
- Authors: Parwada, Cosmas
- Date: 2017
- Subjects: Soil erosion Soil management -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4824 , vital:28531
- Description: Soil organic matter (SOM) plays a primary role in aggregation and stabilization of soils, hence reducing their susceptibility to erosion. In South Africa (SA), most soils have low (< 4 percent) soil organic matte (SOM) contents, making them susceptible to soil erosion. Little is known about SOM quality effects in soil stabilization in the SA context, it is therefore difficult to advocate specific organic matter sources in order to stabilize a particular soil. This study evaluated effects of different litter quality sources (Vachellia karoo (sweet thorn) leaf litter and Zea mays (maize) stover) on soil aggregate stabilization at a soil micro-level (soil aggregate), guided by the following specific objectives; (i) to characterize soil properties that influence the erodibility of soils in the Ntabelanga area, Eastern Cape (EC) Province, SA (ii) to assess fractionation of organic carbon during decomposition of different litter sources (iii) to determine rate of soil macroaggregate re-formation under different litter amendments (iv) to determine the influence of different litter quality on splash soil erosion and (v) to delineate the Ntabelanga area into different soil erosion sensitivity zones. Soil samples collected from a proposed Ntabelanga dam site, EC Province, SA, were characterized for factors influencing erodibility. Soil physical and chemical properties were analyzed, soil erodibility (K-factor) estimated using SOC content and surface properties and soil loss rates by splashing determined under rainfall simulations at 360 mm h-1 rainfall intensity. Soil loss was then correlated with the chemical and physical soil properties. SOC showed significant (P< 0.05) inverse relationship with soil loss. Soils samples were bulked to seven composite samples according to major soil horizons (orthic A, melanic A, pedocutanic B, red apedal B, saprolite, G horizon and prismacutanic B) in the areas of soil associations, macroaggregate (> 0.250 mm) were removed by passing through a 0.250 mm sieve. The remaining soil microaggregates (< 0.250 mm) were then mixed with high quality Vachellia karoo leaf litter (C/N = 23.8) and low quality Zea mays stover (C/N = 37.4) and incubated at 23oC for 30 weeks. Jars were arranged as a 7 × 3 factorial laid in completely randomized design (CRD) with three replicates. Data was repeatedly measured at 1, 3, 8, 14, 23 and 30 weeks after incubation: to determine the stabilization of SOM by fractionating the soil particulate organic matter (POM), rate of soil macroaggregate re-formation and influence of litter quality on splash soil erosion along a decomposition continuum. Free light fractions (Free LF), coarse particulate organic matter (CoPOM) and fine particulate organic matter (FiPOM) within macroaggregates (> 250 μm) decreased exponentially from week 1 to 30 and were significantly (p < 0.05) influenced by litter quality × soil horizon × time interactions. A similar trend for FiPOM fractions in macroaggregates was observed in the 53-250 μm microaggregates (p < 0.05). The greatest influence on changes in POM fractions occurred within the first 3 weeks of incorporation. Both V. karroo leaf litter and Z. mays stover significantly stabilized the macroaggregates within the first 3 weeks after incubation. Cumulative macroaggregates yields, mean weight diameter (MWD), percentage water stable aggregates (%WSA) and whole soil stability index (WSSI) in litter amended soils increased up to week 8 of incubation and thereafter gradually declined in all soils. An increase in macroaggregation resulted in increased MWD, WSSI values and large and small aggregates distribution. Aggregation was significantly higher in soils with higher clay content than sand content, suggesting that soil texture was highly influential in litter decomposition. Rate of litter decomposition was influenced by soil type × time interactions which determined extent and macroaggregation dynamics along a decomposition continuum. The amount of splashed sediments was determined from each soil horizon at 360 mm h-1 simulated rainfall intensity applied as either single 8minute rainstorm (SR) or 4 × 2minute intermittent rainstorms (IR) separated by a 72 h drying period. Results showed a reduction in splashed sediments under IR and SR storms in litter-amended soils during the first 8 weeks of incubation with gradual increase thereafter. More sediments were splashed under IR than SR and litter quality had no influence on splashed sediments per soil horizon. Soil horizons profile with more clay than sand particles enhanced the litter effects on the soil resistance against detachment. The amount of SOC loss was influenced by primary particle size distribution and initial SOC content of the soil. Rainfall pattern and the initial SOC content were the main factors by which different soils influenced SOC loss. More rainstorm patterns should be investigated on these soils.
- Full Text:
- Date Issued: 2017
Sedimentary, geochemical and geophysical study of the Ecca group, Karoo supergroup and its hydrocarbon potential in the Eastern Cape Province, South Africa
- Authors: Baiyegunhi, Christopher
- Date: 2017
- Subjects: Sediments (Geology) -- South Africa -- Eastern Cape Sedimentology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4881 , vital:28658
- Description: The Ecca Group of Karoo Supergroup is a sedimentary rock sequence that deposited between the Late Carboniferous (Dwyka Group) and the Late Permian-Middle Triassic (Beaufort Group). The Ecca Group investigated in this study is situated in the Eastern Cape Province of South Africa and it comprises mainly of shales, mudstones, siltstones and sandstones. The Ecca Group sequence contains considerable carbon content and suitable thickness to make it an ideal target for shale gas exploration. Previous studies put more emphasis on the geology and stratigraphy of the Ecca Group, this study revised the stratigraphy, and put new insight on the petrography, depositional processes, sedimentary facies, provenance, paleoweathering, tectonic setting, subsidence rates and history, electrical resistivity, source rock characteristics and diagenesis of the potentially feasible sandstone and mudrock reservoir rocks of the Ecca Group. Based on the lithological features, sedimentary structures and facies characteristics, the stratigraphy of the Prince Albert, Whitehill, Collingham and Fort Brown Formations of the Ecca Group is now subdivided into two informal members each, i.e. Lower Member and Upper Member. Furthermore, the Ripon Formation is now subdivided into three informal members. Each member has been asigned a lithological name. The grain size parameters show that most of the Ecca Group sandstones are very fine to fine grained, poorly to moderately well sorted, mostly near-symmetrical and mesokurtic in grain-size distribution. The linear discriminant function analysis is dominantly indicative of turbidity current deposits under deep marine environment for Prince Albert, Whitehill and Collingham Formations, shallow marine environment for Ripon Formation, while the Fort Brown Formation is lacustrine-deltaic deposits. Modal composition analysis and petrography studies revealed that the detrital components of the sandstones are dominated by monocrystalline quartz, feldspar and lithic fragments. The sandstones are compositionally and texturally immature and can be classified as feldspathic wacke and lithic wacke. The provenance analysis revealed plutonic and metamorphic terrains as the main source rocks with minor debris derived from recycled sedimentary rocks. The detrital modal compositions of these sandstones are related to back arc to island and continental margin of tectonic setting. Based on the detailed sedimentological analyses of outcrop and borehole data, fourteen lithofacies were identified and seven facies associations (FAs) were recognised. The facies associations are: FA 1: Shale and mudstones intercalated with siltstones, FA 2: Carbonaceous shale, mudstone with subordinate chert and sandstone, FA 3: Mudstones rhythmite with thin bedded mudstone and lenticular siltstone, FA 4: Greyish medium bedded sandstone intercalated with laminated mudstone, FA 5: Dark-grey medium to thick bedded mudstone and siltstone, FA 6: Thin to medium bedded sandstone alternated with thin bedded carbonaceous mudstone, and FA 7: Varved mudstone rhythmite intercalated with siltstone and minor sandstone. Sedimentological characteristics of the identified facies associations indicate four deposition environments, namely, deep marine basin, turbidite, shallow marine and lacustrine environments, which constitute a gradually regression sequence as a result of sea-level dropping and shallowing of the basin during the developmental processes. Geochemical analysis of the Ecca mudrocks and sandstones revealed that the rocks are of quartzose sedimentary provenance, suggesting that they were derived from a cratonic interior or recycled orogen. The petrography and geochemistry of the sandstones indicated that the source areas are composed of plutonic and metamorphic rocks with a minor component from sedimentary rocks. The geochemical diagrams and indices of weathering suggested that the granitic source rocks underwent moderate to high degree of chemical weathering. The tectonic setting discrimination diagrams support passive continental margin setting of the provenance.
- Full Text:
- Date Issued: 2017
- Authors: Baiyegunhi, Christopher
- Date: 2017
- Subjects: Sediments (Geology) -- South Africa -- Eastern Cape Sedimentology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/4881 , vital:28658
- Description: The Ecca Group of Karoo Supergroup is a sedimentary rock sequence that deposited between the Late Carboniferous (Dwyka Group) and the Late Permian-Middle Triassic (Beaufort Group). The Ecca Group investigated in this study is situated in the Eastern Cape Province of South Africa and it comprises mainly of shales, mudstones, siltstones and sandstones. The Ecca Group sequence contains considerable carbon content and suitable thickness to make it an ideal target for shale gas exploration. Previous studies put more emphasis on the geology and stratigraphy of the Ecca Group, this study revised the stratigraphy, and put new insight on the petrography, depositional processes, sedimentary facies, provenance, paleoweathering, tectonic setting, subsidence rates and history, electrical resistivity, source rock characteristics and diagenesis of the potentially feasible sandstone and mudrock reservoir rocks of the Ecca Group. Based on the lithological features, sedimentary structures and facies characteristics, the stratigraphy of the Prince Albert, Whitehill, Collingham and Fort Brown Formations of the Ecca Group is now subdivided into two informal members each, i.e. Lower Member and Upper Member. Furthermore, the Ripon Formation is now subdivided into three informal members. Each member has been asigned a lithological name. The grain size parameters show that most of the Ecca Group sandstones are very fine to fine grained, poorly to moderately well sorted, mostly near-symmetrical and mesokurtic in grain-size distribution. The linear discriminant function analysis is dominantly indicative of turbidity current deposits under deep marine environment for Prince Albert, Whitehill and Collingham Formations, shallow marine environment for Ripon Formation, while the Fort Brown Formation is lacustrine-deltaic deposits. Modal composition analysis and petrography studies revealed that the detrital components of the sandstones are dominated by monocrystalline quartz, feldspar and lithic fragments. The sandstones are compositionally and texturally immature and can be classified as feldspathic wacke and lithic wacke. The provenance analysis revealed plutonic and metamorphic terrains as the main source rocks with minor debris derived from recycled sedimentary rocks. The detrital modal compositions of these sandstones are related to back arc to island and continental margin of tectonic setting. Based on the detailed sedimentological analyses of outcrop and borehole data, fourteen lithofacies were identified and seven facies associations (FAs) were recognised. The facies associations are: FA 1: Shale and mudstones intercalated with siltstones, FA 2: Carbonaceous shale, mudstone with subordinate chert and sandstone, FA 3: Mudstones rhythmite with thin bedded mudstone and lenticular siltstone, FA 4: Greyish medium bedded sandstone intercalated with laminated mudstone, FA 5: Dark-grey medium to thick bedded mudstone and siltstone, FA 6: Thin to medium bedded sandstone alternated with thin bedded carbonaceous mudstone, and FA 7: Varved mudstone rhythmite intercalated with siltstone and minor sandstone. Sedimentological characteristics of the identified facies associations indicate four deposition environments, namely, deep marine basin, turbidite, shallow marine and lacustrine environments, which constitute a gradually regression sequence as a result of sea-level dropping and shallowing of the basin during the developmental processes. Geochemical analysis of the Ecca mudrocks and sandstones revealed that the rocks are of quartzose sedimentary provenance, suggesting that they were derived from a cratonic interior or recycled orogen. The petrography and geochemistry of the sandstones indicated that the source areas are composed of plutonic and metamorphic rocks with a minor component from sedimentary rocks. The geochemical diagrams and indices of weathering suggested that the granitic source rocks underwent moderate to high degree of chemical weathering. The tectonic setting discrimination diagrams support passive continental margin setting of the provenance.
- Full Text:
- Date Issued: 2017
The stability of tolerance of Sorghum spp to Striga asiatica L. Kuntze under diverse conditions and existence of pre-attachment resistance
- Authors: Mandumbu, Ronald
- Date: 2017
- Subjects: Sorghum Sorghum -- Drought tolerance Sorghum -- Effect of drought on
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/2788 , vital:28088
- Description: Sorghum is the fifth most important cereal in the world and a staple food for humans. It is also a source of food and fodder for animals. In addition to the abiotic stresses such as drought, parasitic weeds of the genus Striga cause losses in sorghum production in sub Saharan Africa. Striga asiatica is a parasitic weed that attacks cereals in low input agricultural systems and is distributed throughout semi- arid regions of Africa. Most sorghum producing farmers rely on tolerance for their harvests in Striga infested fields yet the stability of tolerance in the face of a changing climate (recurrent droughts), new farming systems (mulch based agriculture) and existence of various Striga strains needs further investigation. Reduced strigolactones production was also studied as a resistance mechanism. The first study was focused on the determination of tolerance of Striga asiatica infested sorghum under drought in a pot study. Five sorghum lines were subjected to infestation with Striga and some were not infested while watering was done at 50 percent field capacity (FC) and 100 percent FC. The results showed that the five sorghum lines differed significantly in chlorophyll content and Normalised Differential Vegetation Index (NDVI). Infection did not lower chlorophyll content when it co-occurred with drought across all sorghum lines. Drought and infestation had mutually exclusive effects on chlorophyll content and NDVI. Under infestation, internode length was similar both at 100 percent FC and at 50 percent FC while under uninfested conditions, 100 percent FC gave the longer internode compared to 50 percent FC. Both infestation and irrigation regime reduced the sorghum head weight, illustrating that the two effects have synergistic effects on sorghum head weight. The second study sought to determine the effects of mulching and infestation on sorghum spp tolerance to Striga asiatica. The experiments were carried out in the seasons 2013/14 and 2014/15 summer seasons. The results indicated that mulching increased chlorophyll content in the 2014/15 season which was a drier season compared to 2013/14. In the 2014/15 season, mulching increased chlorophyll content in all varieties except Ruzangwaya, Mukadziusaende and SC Sila. When the same varieties were infested under mulch and infested without mulch, the results showed that mulching overcomes the effects of infestation in some varieties. Mulch also negates the effect of Striga parasitism and results in yield maintenance in sorghum varieties. The third study sought to determine the stability of sorghum lines when exposed to two Striga asiatica lines sourced from two places which are 500 km apart in Zimbabwe. The two strains were termed the Chiundura and Rushinga strains, based on where they were sourced. The experiments were conducted at Henderson Research Station (HRS) at Mazoe and at Bindura University of Science Education (BUSE). The results showed differential virulence for some traits while the two strains were equally virulent for some traits. The two strains were equally virulent on all sorghum lines with respect to chlorophyll content. The different sorghum lines responded differently to the effects of the two strains. The effects of the two strains were generally similar for head index, root index, and leaf index at all sites. Generally the Chiundura strain was more virulent to sorghum lines compared to Rushinga strain, confirming the existence of physiological strains of Striga in Zimbabwe. Therefore physiological speciation of Striga asiatica exists and this adds a further dimension to the complexity of Striga management in the smallholder sector. Quantification of strigolactone production by different sorghum genotypes was conducted in the laboratory using the agar gel assay. The genotype Mukadziusaende produced significantly the least (P<0.01) quantities of strigolactones, as inferred from the maximum germination distance (MGD) from the sorghum root. The MGD was negatively correlated to tiller numbers illustrating that the more the strigolactones the less the tillering capacity. Tiller numbers and MGD can therefore be used to select for reduced strigolactones production.
- Full Text:
- Date Issued: 2017
- Authors: Mandumbu, Ronald
- Date: 2017
- Subjects: Sorghum Sorghum -- Drought tolerance Sorghum -- Effect of drought on
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/2788 , vital:28088
- Description: Sorghum is the fifth most important cereal in the world and a staple food for humans. It is also a source of food and fodder for animals. In addition to the abiotic stresses such as drought, parasitic weeds of the genus Striga cause losses in sorghum production in sub Saharan Africa. Striga asiatica is a parasitic weed that attacks cereals in low input agricultural systems and is distributed throughout semi- arid regions of Africa. Most sorghum producing farmers rely on tolerance for their harvests in Striga infested fields yet the stability of tolerance in the face of a changing climate (recurrent droughts), new farming systems (mulch based agriculture) and existence of various Striga strains needs further investigation. Reduced strigolactones production was also studied as a resistance mechanism. The first study was focused on the determination of tolerance of Striga asiatica infested sorghum under drought in a pot study. Five sorghum lines were subjected to infestation with Striga and some were not infested while watering was done at 50 percent field capacity (FC) and 100 percent FC. The results showed that the five sorghum lines differed significantly in chlorophyll content and Normalised Differential Vegetation Index (NDVI). Infection did not lower chlorophyll content when it co-occurred with drought across all sorghum lines. Drought and infestation had mutually exclusive effects on chlorophyll content and NDVI. Under infestation, internode length was similar both at 100 percent FC and at 50 percent FC while under uninfested conditions, 100 percent FC gave the longer internode compared to 50 percent FC. Both infestation and irrigation regime reduced the sorghum head weight, illustrating that the two effects have synergistic effects on sorghum head weight. The second study sought to determine the effects of mulching and infestation on sorghum spp tolerance to Striga asiatica. The experiments were carried out in the seasons 2013/14 and 2014/15 summer seasons. The results indicated that mulching increased chlorophyll content in the 2014/15 season which was a drier season compared to 2013/14. In the 2014/15 season, mulching increased chlorophyll content in all varieties except Ruzangwaya, Mukadziusaende and SC Sila. When the same varieties were infested under mulch and infested without mulch, the results showed that mulching overcomes the effects of infestation in some varieties. Mulch also negates the effect of Striga parasitism and results in yield maintenance in sorghum varieties. The third study sought to determine the stability of sorghum lines when exposed to two Striga asiatica lines sourced from two places which are 500 km apart in Zimbabwe. The two strains were termed the Chiundura and Rushinga strains, based on where they were sourced. The experiments were conducted at Henderson Research Station (HRS) at Mazoe and at Bindura University of Science Education (BUSE). The results showed differential virulence for some traits while the two strains were equally virulent for some traits. The two strains were equally virulent on all sorghum lines with respect to chlorophyll content. The different sorghum lines responded differently to the effects of the two strains. The effects of the two strains were generally similar for head index, root index, and leaf index at all sites. Generally the Chiundura strain was more virulent to sorghum lines compared to Rushinga strain, confirming the existence of physiological strains of Striga in Zimbabwe. Therefore physiological speciation of Striga asiatica exists and this adds a further dimension to the complexity of Striga management in the smallholder sector. Quantification of strigolactone production by different sorghum genotypes was conducted in the laboratory using the agar gel assay. The genotype Mukadziusaende produced significantly the least (P<0.01) quantities of strigolactones, as inferred from the maximum germination distance (MGD) from the sorghum root. The MGD was negatively correlated to tiller numbers illustrating that the more the strigolactones the less the tillering capacity. Tiller numbers and MGD can therefore be used to select for reduced strigolactones production.
- Full Text:
- Date Issued: 2017
Effects of grazing and housing management systems on greenhouse gas emissions, blood profiles and meat quality of Nguni goats
- Authors: Tapiwa, Chikwanda Allen
- Date: 2016
- Subjects: Goats Goats -- Feeding and feeds Greenhouse gas mitigation , Grazing -- Environmental aspects
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/2314 , vital:27752
- Description: The broad objective of this study was to evaluate the effects of grazing and housing management systems on greenhouse gas emissions, blood profiles and meat quality of Nguni goats. A total of 64 castrated Nguni goats were used and a housing structure was designed to accommodate the goats as well as evaluate effects of type of floor on greenhouse gases, meat quality, blood metabolites and fatty acid profiles. In the first experiment: Forty-eight castrated Nguni goats, at 6-7 months old were used for herding (H) or tethering (T) management systems and randomly allocated to pens with earth (E) or slatted (S) floors. Gas sampling was done using static chambers and analysed using a SRI 8610C gas chromatography machine. The highest CH4 fluxes were from the manure of herded goats on earth floors (HE). The highest CO2 fluxes were from manure of herded goats that were housed on slatted floors (HS): The highest N2O fluxes were from the manure of tethered goats that were sheltered on slatted floors (TS). It was concluded from the first experiment that goat manure is an important source of GHG that is influenced by grazing and floor type management systems. The second experiment was done to evaluate greenhouse gas (GHG) emission from disused (DP) vs occupied goat pens (OP) with earth (EF) or slatted (SF) floors. Eight previously occupied pens were used in this study. Sixteen goats were randomly put in the pens labelled occupied pens with earth floors (OPEF) and occupied pens with slatted floors (OPSF) resulting in four goats per OP. There were month by pen use; month by floor type; and use by floor type interaction effects (P < 0.05) on CH4 production. Floor type, use (DP vs OP) and month affected (P < 0.05) CH4 production. Manure on earth floors of occupied pens (OPEF) emitted the highest (P < 0.05) methane followed by earth floors of disused pens (DPEF). The least CH4 was emitted from DPSF. There was pen use (DP vs OP) by floor type interaction effect (P < 0.05) on CO2 emission. Floor type and pen use affected (P < 0.05) CO2 production. Manure in occupied pens with slatted floors (OPSF) produced the highest CO2 and the least CO2 was from disused pens with slatted floors (DPSF). Floor type and month influenced (P < 0.05) N2O production. It was concluded that continued use of goat pens increased GHG emissions. However, disused goat pens with manure remain an important source of GHG as they continued to emit quantifiable levels of CH4, CO2 and N2O. The third experiment was done to determine the effects of grazing and housing management systems on the concentrations of blood metabolites, activity of creatine kinase, body weight (BW), body condition score (BCS) and carcass characteristics using 48 castrated Nguni goats. Tethered goats had higher (P<0.05): urea, creatinine, total protein, globulin concentrations and more activity of CK than herded goats. On the other hand, herded goats had higher (P<0.05) plasma glucose (H: 3.39±0.020 vs T: 3.23±0.020 mmol/L), serum albumin (H: 15.30±0.147 vs T: 14.82±0.144 g/L) concentration. It was concluded that serum concentrations of all the metabolites and the activity of CK were sensitive to grazing system. Herding of goats promoted more glucose concentration and preservation of muscle protein and hence superior body weights and BCS than tethered goats. The fourth experiment was done to determine the effects of grazing and housing management systems on the activity of creatine kinase (CK) and cortisol concentration, and chevon quality. Further, the effect of muscle type [Muscularis longissimus thoracis et. Lumborum (LTL) and triceps brachii (TB)] on chevon quality was also investigated. Forty eight castrated Nguni goats aged 6- 7 months were randomly allocated to tethering (n=24) and herding (n=24) treatments. Floor type affected meat (P<0.05) pH24. Tethered goats had higher (P < 0.05) L* and CL percent than herded goats. Muscle type had a significant influence (P < 0.05) on a*, WBSF and pH. It was observed and concluded that T resulted in higher L* and more CL percent whilst SF lowered the pH24 of chevon; at the same time meat from the TB muscle was more tender, despite having a higher pH24 and more CL percent relative to LTH cuts. The fifth experiment was done to determine the effect of grazing and floor type on fatty acid composition of chevon from tethered and herded Nguni goats. Floor type had no effect on fatty acid composition. Oleic, stearic, palmitic and linoleic were the major fatty acids. Chevon from tethered goats had higher (P < 0.05) proportions of long chain polyunsaturated fatty acids (PUFAs): eicosapentaenoic, docosapentaenoic, docosahexaenoic, conjugated linoleic acid (CLA) and more total SFA, total PUFA, total Omega- 6 and total omega 3 fatty acids than herded goats. On the other hand, chevon from herded goats had more (P < 0.05) C18:1c9, C18:2t9, 12 (n-6), C20:3c11, 14, 17 (n-3) and total MUFA than tethered goats. However, there was no difference (P > 0.05) in the PUFA: SFA and n-6/n-3 fatty acid ratios between the herded and tethered goats. It was concluded that tethering promoted higher proportions of beneficial PUFAs which were more in TB than LTH muscle. The overall conclusions from the whole study were that goat manure is an important source of GHG with high CH4 being emitted from earth floors of herded goats. High CO2 and N2O are emitted from SF of herded and tethered goats, respectively. There were no major differences in meat quality between herded and tethered goats. However, herding promoted more live weight gain than tethering. On the other hand, tethering promoted more beneficial fatty acids. Therefore depending on the objective of the enterprise, smallholder farmers can safely tether or herd their goats. Further, there is need to develop technologies to harness CH4 from goat manure.
- Full Text:
- Date Issued: 2016
- Authors: Tapiwa, Chikwanda Allen
- Date: 2016
- Subjects: Goats Goats -- Feeding and feeds Greenhouse gas mitigation , Grazing -- Environmental aspects
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/2314 , vital:27752
- Description: The broad objective of this study was to evaluate the effects of grazing and housing management systems on greenhouse gas emissions, blood profiles and meat quality of Nguni goats. A total of 64 castrated Nguni goats were used and a housing structure was designed to accommodate the goats as well as evaluate effects of type of floor on greenhouse gases, meat quality, blood metabolites and fatty acid profiles. In the first experiment: Forty-eight castrated Nguni goats, at 6-7 months old were used for herding (H) or tethering (T) management systems and randomly allocated to pens with earth (E) or slatted (S) floors. Gas sampling was done using static chambers and analysed using a SRI 8610C gas chromatography machine. The highest CH4 fluxes were from the manure of herded goats on earth floors (HE). The highest CO2 fluxes were from manure of herded goats that were housed on slatted floors (HS): The highest N2O fluxes were from the manure of tethered goats that were sheltered on slatted floors (TS). It was concluded from the first experiment that goat manure is an important source of GHG that is influenced by grazing and floor type management systems. The second experiment was done to evaluate greenhouse gas (GHG) emission from disused (DP) vs occupied goat pens (OP) with earth (EF) or slatted (SF) floors. Eight previously occupied pens were used in this study. Sixteen goats were randomly put in the pens labelled occupied pens with earth floors (OPEF) and occupied pens with slatted floors (OPSF) resulting in four goats per OP. There were month by pen use; month by floor type; and use by floor type interaction effects (P < 0.05) on CH4 production. Floor type, use (DP vs OP) and month affected (P < 0.05) CH4 production. Manure on earth floors of occupied pens (OPEF) emitted the highest (P < 0.05) methane followed by earth floors of disused pens (DPEF). The least CH4 was emitted from DPSF. There was pen use (DP vs OP) by floor type interaction effect (P < 0.05) on CO2 emission. Floor type and pen use affected (P < 0.05) CO2 production. Manure in occupied pens with slatted floors (OPSF) produced the highest CO2 and the least CO2 was from disused pens with slatted floors (DPSF). Floor type and month influenced (P < 0.05) N2O production. It was concluded that continued use of goat pens increased GHG emissions. However, disused goat pens with manure remain an important source of GHG as they continued to emit quantifiable levels of CH4, CO2 and N2O. The third experiment was done to determine the effects of grazing and housing management systems on the concentrations of blood metabolites, activity of creatine kinase, body weight (BW), body condition score (BCS) and carcass characteristics using 48 castrated Nguni goats. Tethered goats had higher (P<0.05): urea, creatinine, total protein, globulin concentrations and more activity of CK than herded goats. On the other hand, herded goats had higher (P<0.05) plasma glucose (H: 3.39±0.020 vs T: 3.23±0.020 mmol/L), serum albumin (H: 15.30±0.147 vs T: 14.82±0.144 g/L) concentration. It was concluded that serum concentrations of all the metabolites and the activity of CK were sensitive to grazing system. Herding of goats promoted more glucose concentration and preservation of muscle protein and hence superior body weights and BCS than tethered goats. The fourth experiment was done to determine the effects of grazing and housing management systems on the activity of creatine kinase (CK) and cortisol concentration, and chevon quality. Further, the effect of muscle type [Muscularis longissimus thoracis et. Lumborum (LTL) and triceps brachii (TB)] on chevon quality was also investigated. Forty eight castrated Nguni goats aged 6- 7 months were randomly allocated to tethering (n=24) and herding (n=24) treatments. Floor type affected meat (P<0.05) pH24. Tethered goats had higher (P < 0.05) L* and CL percent than herded goats. Muscle type had a significant influence (P < 0.05) on a*, WBSF and pH. It was observed and concluded that T resulted in higher L* and more CL percent whilst SF lowered the pH24 of chevon; at the same time meat from the TB muscle was more tender, despite having a higher pH24 and more CL percent relative to LTH cuts. The fifth experiment was done to determine the effect of grazing and floor type on fatty acid composition of chevon from tethered and herded Nguni goats. Floor type had no effect on fatty acid composition. Oleic, stearic, palmitic and linoleic were the major fatty acids. Chevon from tethered goats had higher (P < 0.05) proportions of long chain polyunsaturated fatty acids (PUFAs): eicosapentaenoic, docosapentaenoic, docosahexaenoic, conjugated linoleic acid (CLA) and more total SFA, total PUFA, total Omega- 6 and total omega 3 fatty acids than herded goats. On the other hand, chevon from herded goats had more (P < 0.05) C18:1c9, C18:2t9, 12 (n-6), C20:3c11, 14, 17 (n-3) and total MUFA than tethered goats. However, there was no difference (P > 0.05) in the PUFA: SFA and n-6/n-3 fatty acid ratios between the herded and tethered goats. It was concluded that tethering promoted higher proportions of beneficial PUFAs which were more in TB than LTH muscle. The overall conclusions from the whole study were that goat manure is an important source of GHG with high CH4 being emitted from earth floors of herded goats. High CO2 and N2O are emitted from SF of herded and tethered goats, respectively. There were no major differences in meat quality between herded and tethered goats. However, herding promoted more live weight gain than tethering. On the other hand, tethering promoted more beneficial fatty acids. Therefore depending on the objective of the enterprise, smallholder farmers can safely tether or herd their goats. Further, there is need to develop technologies to harness CH4 from goat manure.
- Full Text:
- Date Issued: 2016
Electrical power output estimation model for a conical diffuser augmented wind turbine
- Authors: Masukume, Peace-Maker
- Date: 2016
- Subjects: Wind power , Wind turbines , Renewable energy sources
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/1517 , vital:27404
- Description: Energy is integral to the quality of life of any society. However, meeting the demand for energy sustainably is the main challenge facing humanity. In general, non-renewable energy resources are used to supply the ever increasing energy demand. However, the extraction and processing of these resources is accompanied by the production of wastes which are a health hazard and impact negatively on climate change. Considering the finite nature of non-renewable sources, the environmental concerns which are associated with their usage and ensuring energy security, renewable energy sources have been brought in the energy supply chain. Wind energy is one of the renewable energy sources which has been supplying electrical energy to the ever increasing energy demand of humanity. Wind energy technology is a mature technology which over and above the bare (conventional) wind turbine technology has seen the development of duct augmented wind turbines. Ducts are used to encase wind turbine rotors to augment the power output of wind turbines especially in low wind speed areas. Though the technology has been under study for decades now, research indicates that there is no known model to estimate the power output of a diffuser augmented wind turbine. This thesis presents the development of the conical Diffuser Augmented Wind Turbine (DAWT) power output estimation model and its validation.
- Full Text:
- Date Issued: 2016
- Authors: Masukume, Peace-Maker
- Date: 2016
- Subjects: Wind power , Wind turbines , Renewable energy sources
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/1517 , vital:27404
- Description: Energy is integral to the quality of life of any society. However, meeting the demand for energy sustainably is the main challenge facing humanity. In general, non-renewable energy resources are used to supply the ever increasing energy demand. However, the extraction and processing of these resources is accompanied by the production of wastes which are a health hazard and impact negatively on climate change. Considering the finite nature of non-renewable sources, the environmental concerns which are associated with their usage and ensuring energy security, renewable energy sources have been brought in the energy supply chain. Wind energy is one of the renewable energy sources which has been supplying electrical energy to the ever increasing energy demand of humanity. Wind energy technology is a mature technology which over and above the bare (conventional) wind turbine technology has seen the development of duct augmented wind turbines. Ducts are used to encase wind turbine rotors to augment the power output of wind turbines especially in low wind speed areas. Though the technology has been under study for decades now, research indicates that there is no known model to estimate the power output of a diffuser augmented wind turbine. This thesis presents the development of the conical Diffuser Augmented Wind Turbine (DAWT) power output estimation model and its validation.
- Full Text:
- Date Issued: 2016
Evaluation of flocculating potentials and charecterization of bioflocculants produced by three bacterial isolates from Algoa Bay, South Africa
- Authors: Okaiyeto, Kunle
- Date: 2016
- Subjects: Flocculation Water -- Purification -- Flocculation Water quality management
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/2633 , vital:27947
- Description: Flocculation has been widely adopted as one of the most effective methods to remove colloidal particles in water or wastewater treatment. Synthetic flocculants are conventionally used because of their high flocculating efficiency and cost-effectiveness. However, they have been reported to have hazardous properties and implicated in some serious health problems including senile dementia and neuro-toxicity, as well as being recalcitrant in the environment. Consequently, efforts are being geared away from the use of synthetic flocculants in water and wastewater treatment. Hence, the need for safe and eco-friendly flocculants has become imperative. Compared with synthetic flocculants, bioflocculants have special advantages such as safety, biodegradability and harmlessness to the environment and humans; attributes which make them potential alternatives in water treatment, downstream as well as fermentation processes. In the current study, the potentials of bacterial isolates recovered from Algoa Bay in the Eastern Cape Province of South Africa for bioflocculant production were investigated. The bacterial isolates were identified by polymerase chain reaction (PCR) as belonging to the Bacillus genus. The analysis of 16S ribosomal deoxyribonucleic acid (rDNA) nucleotide sequence of isolate M72 showed 99 percent similarity to Bacillus toyonensis strain BCT-7112 and was deposited in the GenBank as Bacillus toyonensis strain AEMREG6 with accession number KP406731. Likewise, the 16S rDNA nucleotide sequences of isolates M69 and M67 showed 98 percent sequence similarity to Bacillus licheniformis strain W7 and Bacillus algicola strain QD43 respectively; and M67 isolate was subsequently deposited in the GenBank as Bacillus sp. AEMREG7 with accession number KF933697.1. The results of the nutritional requirements and fermentation conditions revealed that optimum inoculum size for REG-6 production was 4 percent (v/v), while 5 percent (v/v) and 3 percent (v/v) were most favourable for MBF-W7 and MBF-UFH production respectively. Glucose was the best carbon source for the production of bioflocculants (REG-6 and MBF-UFH) by Bacillus toyonensis AEMREG6 and Bacillus sp. AEMREG7 respectively, while maltose supported optimum bioflocculant (MBF-W7) production by Bacillus specie. Inorganic nitrogen (NH4NO3) was the favoured nitrogen source for both REG-6 and MBF-W7 production, while mixed nitrogen sources [yeast extract + urea + (NH4)2SO4] supported the maximum production of MBF-UFH. The initial medium pH for REG-6 was 5, while MBF-W7 and MBF-UFH were both maximally produced at the initial pH of 6. After a 96 h cultivation period under optimal culture conditions, 3.2 g of purified REG-6 with a maximum flocculating activity of 77 percent was recovered from 1 L fermented broth of Bacillus toyonensis AEMREG6. Yields of 3.8 g and 1.6 g pure bioflocculants with the respective highest flocculating activities of 94.9 percent and 83.2 percent were also obtained from 1 L, 72 h-fermented broths of Bacillus licheniformis and Bacillus sp. AEMREG7 respectively. Furthermore, all the three bioflocculants (REG-6, MBF-W7 and MBF-UFH), displayed thermal stability within the temperature range of 50 to 100 oC, with strong flocculating activities of over 80 percent against kaolin suspension over a wide range of pH range (3–11) and relatively low dosage requirements of 0.1-03 mg/ml in the presence of divalent cations in the treatment of kaolin clay suspension and Thyme River waters. Chemical composition analyses of the bioflocculants showed them to be glycoproteins with a predominantly polysaccharide backbones as shown by the following carbohydrate/protein (w/w) ratios: 77.8 percent:11.5 percent (REG-6); 73.7 percent:6.2 percent (MBF-W7) and 76 percent:14 percent (MBF-UFH).
- Full Text:
- Date Issued: 2016
- Authors: Okaiyeto, Kunle
- Date: 2016
- Subjects: Flocculation Water -- Purification -- Flocculation Water quality management
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/2633 , vital:27947
- Description: Flocculation has been widely adopted as one of the most effective methods to remove colloidal particles in water or wastewater treatment. Synthetic flocculants are conventionally used because of their high flocculating efficiency and cost-effectiveness. However, they have been reported to have hazardous properties and implicated in some serious health problems including senile dementia and neuro-toxicity, as well as being recalcitrant in the environment. Consequently, efforts are being geared away from the use of synthetic flocculants in water and wastewater treatment. Hence, the need for safe and eco-friendly flocculants has become imperative. Compared with synthetic flocculants, bioflocculants have special advantages such as safety, biodegradability and harmlessness to the environment and humans; attributes which make them potential alternatives in water treatment, downstream as well as fermentation processes. In the current study, the potentials of bacterial isolates recovered from Algoa Bay in the Eastern Cape Province of South Africa for bioflocculant production were investigated. The bacterial isolates were identified by polymerase chain reaction (PCR) as belonging to the Bacillus genus. The analysis of 16S ribosomal deoxyribonucleic acid (rDNA) nucleotide sequence of isolate M72 showed 99 percent similarity to Bacillus toyonensis strain BCT-7112 and was deposited in the GenBank as Bacillus toyonensis strain AEMREG6 with accession number KP406731. Likewise, the 16S rDNA nucleotide sequences of isolates M69 and M67 showed 98 percent sequence similarity to Bacillus licheniformis strain W7 and Bacillus algicola strain QD43 respectively; and M67 isolate was subsequently deposited in the GenBank as Bacillus sp. AEMREG7 with accession number KF933697.1. The results of the nutritional requirements and fermentation conditions revealed that optimum inoculum size for REG-6 production was 4 percent (v/v), while 5 percent (v/v) and 3 percent (v/v) were most favourable for MBF-W7 and MBF-UFH production respectively. Glucose was the best carbon source for the production of bioflocculants (REG-6 and MBF-UFH) by Bacillus toyonensis AEMREG6 and Bacillus sp. AEMREG7 respectively, while maltose supported optimum bioflocculant (MBF-W7) production by Bacillus specie. Inorganic nitrogen (NH4NO3) was the favoured nitrogen source for both REG-6 and MBF-W7 production, while mixed nitrogen sources [yeast extract + urea + (NH4)2SO4] supported the maximum production of MBF-UFH. The initial medium pH for REG-6 was 5, while MBF-W7 and MBF-UFH were both maximally produced at the initial pH of 6. After a 96 h cultivation period under optimal culture conditions, 3.2 g of purified REG-6 with a maximum flocculating activity of 77 percent was recovered from 1 L fermented broth of Bacillus toyonensis AEMREG6. Yields of 3.8 g and 1.6 g pure bioflocculants with the respective highest flocculating activities of 94.9 percent and 83.2 percent were also obtained from 1 L, 72 h-fermented broths of Bacillus licheniformis and Bacillus sp. AEMREG7 respectively. Furthermore, all the three bioflocculants (REG-6, MBF-W7 and MBF-UFH), displayed thermal stability within the temperature range of 50 to 100 oC, with strong flocculating activities of over 80 percent against kaolin suspension over a wide range of pH range (3–11) and relatively low dosage requirements of 0.1-03 mg/ml in the presence of divalent cations in the treatment of kaolin clay suspension and Thyme River waters. Chemical composition analyses of the bioflocculants showed them to be glycoproteins with a predominantly polysaccharide backbones as shown by the following carbohydrate/protein (w/w) ratios: 77.8 percent:11.5 percent (REG-6); 73.7 percent:6.2 percent (MBF-W7) and 76 percent:14 percent (MBF-UFH).
- Full Text:
- Date Issued: 2016
Evaluation of the incidence of enteric viruses, Vibrio species and Escherichia coli pathotypes in effluents of two wastewater treatment plants located in Keiskammahoek and Stutterheim in the Eastern Cape Province of South Africa
- Authors: Adefisoye, Martins Ajibade
- Date: 2016
- Subjects: Escherichia coli -- South Africa -- Eastern Cape Water -- Purification -- South Africa -- Eastern Cape Effluent quality -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/3165 , vital:28328
- Description: South Africa is currently experiencing water shortage crisis, a challenge that has been attributed not only to the scarcity of freshwater, but also to fast degrading water quality. Factors such as rapid urbanisation, population and economic growth, climate change as well as poor operational and maintenance of many of the exisiting water/wastewater treatment facilities have been acknowledged as important contributors to degrading water quality in the country. Untreated or inadequately treated discharged wastewater effluents constitute point source pollution to many freshwater environments in South Africa. Hence, it becomes imperative to evaluate wastewater discharges in other to protect the scarce freshwater resource, the environment and public health. Over a twelve-month sampling period (September 2012 to August 2013), we assessed the bacteriological, virological and physicochemical qualities of the discharged final effluents of two wastewater treatment facilities in the Eastern Cape Province of South Africa. For the physicochemical assessment, a total of 144 final effluent samples were collected from both the final effluent tanks (FE) and the discharge points (DP) of the treatment facilities. Physicochemical parameters including pH, temperature, turbidity, total dissolved solids (TDS), dissolved oxygen (DO), electrical conductivity (EC) and free chlorine concentration were determined on site while biological oxygen demand (BOD), nitrate (NO3-), nitrite (NO2-), phosphate (PO4-) and chemical oxygen demand (COD) were determined in the laboratory. The bacteriological analysis of the samples was done using standard membrane filtration (MF) technique. Bacterial group assessed included: faecal indicator bacteria (faecal coliforms and E. coli) and Vibrio species, while the antibiotic susceptibility profiles of selected E. coli and Vibrio species isolates against some selected antibiotics commonly used in human therapy and veterinary medicine were determind using the standard agar-disc diffusion method. The occurrence and concentrations of human enteric viruses including: human adenovirus (HAdV), hepatitis A virus (HAV) and rotavirus (RoV) in the samples were determined by TaqMan-based real-time polymerase chain reaction (qPCR) following concentration by adsorption-elution method. The physicochemical characteristics of the samples ranged as follows: pH (6.5 – 7.6), TDS (95 – 171 mg/L), EC (134 – 267 μS/cm), temperature (12 – 27 °C), turbidity (1.5 – 65.7 mg/L), free chlorine (0.08 – 0.72 mg/L), DO (2.06 – 9.81 mg/L), BOD (0.13 – 9.81 mg/L), NO3- (0 – 21.5 mg/L), NO2- (0 – 0.72 mg/L), PO4- (0 – 18.3 mg/L) and COD (27 – 680 mg/L). Some of the characteristic such as pH, TDS, EC, temperature, nitrite and DO (on most instances) complied with recommended guidelines. Other characteristics, however, including turbidity, BOD, nitrate, phosphate and COD fell short of the recommended guidelines. All the 48 samples analysed for bacteriological qualities tested positive for the presence of the bacterial groups with significant (P≤0.05) seasonal variation in their densities. Faecal coliforms were detected in counts ranging from 1 CFU/100ml to 2.7 × 104 CFU/100ml. Presumptive E. coli counts ranged generally between 1 CFU/100ml – 1.4 × 105 CFU/100ml while counts of presumptive Vibrio species ranged between 4 CFU/100ml – 1.4 × 104 CFU/100ml. Molecular identification of the presumptive isolates by polymerase chain reactions PCR gave positive reaction rates of 76.2 percent (381/500) and 69.8 percent (279/400) for E.coli and Vibrio species respectively. The antibiotic susceptibility profiling of 205 PCR-confirmed Vibiro isolates against 18 commomly used antibiotics showed resistance frequencies ranging from 0.5 percent (imipenem) to 96.1 percent (penicillin G) at recommended breakpoint concentrations. Eighty-one percent (166/205) of the Vibrio isolates showed multidrug resistance (resistance to 3 or more antibiotics) with the most common multiple antibiotic resistance phenotype (MARP) being AP-T-TM-SMX-PG-NI-PB, occurring in 8 isolates.
- Full Text:
- Date Issued: 2016
- Authors: Adefisoye, Martins Ajibade
- Date: 2016
- Subjects: Escherichia coli -- South Africa -- Eastern Cape Water -- Purification -- South Africa -- Eastern Cape Effluent quality -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/3165 , vital:28328
- Description: South Africa is currently experiencing water shortage crisis, a challenge that has been attributed not only to the scarcity of freshwater, but also to fast degrading water quality. Factors such as rapid urbanisation, population and economic growth, climate change as well as poor operational and maintenance of many of the exisiting water/wastewater treatment facilities have been acknowledged as important contributors to degrading water quality in the country. Untreated or inadequately treated discharged wastewater effluents constitute point source pollution to many freshwater environments in South Africa. Hence, it becomes imperative to evaluate wastewater discharges in other to protect the scarce freshwater resource, the environment and public health. Over a twelve-month sampling period (September 2012 to August 2013), we assessed the bacteriological, virological and physicochemical qualities of the discharged final effluents of two wastewater treatment facilities in the Eastern Cape Province of South Africa. For the physicochemical assessment, a total of 144 final effluent samples were collected from both the final effluent tanks (FE) and the discharge points (DP) of the treatment facilities. Physicochemical parameters including pH, temperature, turbidity, total dissolved solids (TDS), dissolved oxygen (DO), electrical conductivity (EC) and free chlorine concentration were determined on site while biological oxygen demand (BOD), nitrate (NO3-), nitrite (NO2-), phosphate (PO4-) and chemical oxygen demand (COD) were determined in the laboratory. The bacteriological analysis of the samples was done using standard membrane filtration (MF) technique. Bacterial group assessed included: faecal indicator bacteria (faecal coliforms and E. coli) and Vibrio species, while the antibiotic susceptibility profiles of selected E. coli and Vibrio species isolates against some selected antibiotics commonly used in human therapy and veterinary medicine were determind using the standard agar-disc diffusion method. The occurrence and concentrations of human enteric viruses including: human adenovirus (HAdV), hepatitis A virus (HAV) and rotavirus (RoV) in the samples were determined by TaqMan-based real-time polymerase chain reaction (qPCR) following concentration by adsorption-elution method. The physicochemical characteristics of the samples ranged as follows: pH (6.5 – 7.6), TDS (95 – 171 mg/L), EC (134 – 267 μS/cm), temperature (12 – 27 °C), turbidity (1.5 – 65.7 mg/L), free chlorine (0.08 – 0.72 mg/L), DO (2.06 – 9.81 mg/L), BOD (0.13 – 9.81 mg/L), NO3- (0 – 21.5 mg/L), NO2- (0 – 0.72 mg/L), PO4- (0 – 18.3 mg/L) and COD (27 – 680 mg/L). Some of the characteristic such as pH, TDS, EC, temperature, nitrite and DO (on most instances) complied with recommended guidelines. Other characteristics, however, including turbidity, BOD, nitrate, phosphate and COD fell short of the recommended guidelines. All the 48 samples analysed for bacteriological qualities tested positive for the presence of the bacterial groups with significant (P≤0.05) seasonal variation in their densities. Faecal coliforms were detected in counts ranging from 1 CFU/100ml to 2.7 × 104 CFU/100ml. Presumptive E. coli counts ranged generally between 1 CFU/100ml – 1.4 × 105 CFU/100ml while counts of presumptive Vibrio species ranged between 4 CFU/100ml – 1.4 × 104 CFU/100ml. Molecular identification of the presumptive isolates by polymerase chain reactions PCR gave positive reaction rates of 76.2 percent (381/500) and 69.8 percent (279/400) for E.coli and Vibrio species respectively. The antibiotic susceptibility profiling of 205 PCR-confirmed Vibiro isolates against 18 commomly used antibiotics showed resistance frequencies ranging from 0.5 percent (imipenem) to 96.1 percent (penicillin G) at recommended breakpoint concentrations. Eighty-one percent (166/205) of the Vibrio isolates showed multidrug resistance (resistance to 3 or more antibiotics) with the most common multiple antibiotic resistance phenotype (MARP) being AP-T-TM-SMX-PG-NI-PB, occurring in 8 isolates.
- Full Text:
- Date Issued: 2016
Evaluation of the medicinal potentials of Bulbine Abyssinica A. rich in the management of diabetes mellitus in the Eastern Cape, South Africa
- Authors: Kibiti, Cromwell Mwiti
- Date: 2016
- Subjects: Medicinal plants -- South Africa -- Eastern Cape Diabetes -- Alternative treatment -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/3077 , vital:28252
- Description: Diabetes mellitus is a chronic physiological carbohydrate metabolic disorder with significant impact on the economy, quality of life and life expectancy in South Africa. Herbal medicine has become the alternative therapy in the management of this disease. However, their safety and effectiveness have not been investigated. To address this, one of the plants used in Eastern Cape Province, South Africa, Bulbine abyssinica A. Rich (Asphodelaceae), was evaluated. Bulbine abyssinica is one of the species used in the management of diabetes mellitus. This plant was mentioned during an ethnobotanical survey conducted in Nkonkobe municipality of the Eastern Cape Province. Though a decoction prepared from the whole plant is used in the treatment of diabetes mellitus, the mechanism of action and its safety has not been elucidated. Thus, this research work was designed to contribute to the understanding of the possible mechanism of action of B. abyssinica as an antidiabetic medicinal plant and its toxic potentials to the users. The aqueous extract exhibited remarkable inhibitory activity onα-amylase (estimated inhibitory concentration (IC)50 value of 3.28 μg/ml), while the acetone extract exhibited weak inhibitory activity. The acetone extract exhibited notable α-glucosidase inhibitory activity (IC50 value of 4.27 μg/ml) while aqueous extract had significantly weak activity. The Lineweaver-Burk double reciprocal plots revealed that the aqueous extract exerts noncompetitive inhibition on the α-amylase activity while the acetone extract exerts a near competitive inhibitory pattern on the α-glucosidase activity. The extracts from the plant possessed high free radical scavenging activities, with acetone extract exhibiting the highest activities in all assay models used except with ferric reducing power and nitric oxide (NO) scavenging ability. The aqueous extract exhibited the highest ferric reducing power and nitric oxide radical mopping strength while the essential oil exhibited the highest scavenging activities with 1,1-diphenyl-2-picrylhydrazyl (DPPH) and relatively high ferric reducing power and nitric oxide scavenging ability. The acetone extract and the essential oil of this species exhibited higher albumin denaturation inhibition than the aqueous extract while the latter showed the greatest membrane lysis protection. The essential oil, acetone and aqueous extracts from this plant significantly inhibited the growth of Shigelle flexneri, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis. Klebsiella pneumonia, Proteus vulgaris and Streptococcus pyogens growth were inhibited by acetone and aqueous extracts. The essential oil also showed inhibitory activity against Proteus vulgaris. However, the extracts were active against the growth of only three fungi species. The essential oil showed significant inhibitory activity against Trichophyton rubrum. The aqueous extract inhibited the growth of Microsporum gypseum while the acetone extract was active against Microsporum canis, and Microsporum gypseum. The carbohydrate, crude fibre, moisture, ash, crude protein and crude fat of approximately 74.8 percent, 8.9 percent, 8.8 percent, 8 percent, 7.7 percent and 0.6 percent, respectively, were detected in this plant. The species is characterized by moderate levels of oxalates, phytic acids, Vitamin A, Vitamin C and Vitamin E. Potassium and calcium were present in highest levels, while magnesium, iron, sodium, aluminium and phosphorus were moderately present. Manganese, zinc and copper where in low amounts. These vitamins and mineral elements were within their recommended daily allowance (RDA) in humans. The investigation also revealed appreciable amounts of total phenols, flavonoids, flavanols, proanthocyanidins and alkaloids in both acetone and aqueous extracts while saponins and tannins were in trace amounts. The essential oil was characterized by large quantities of terpenes (91.9 percent) and small fraction of esters (8.01 percent).
- Full Text:
- Date Issued: 2016
- Authors: Kibiti, Cromwell Mwiti
- Date: 2016
- Subjects: Medicinal plants -- South Africa -- Eastern Cape Diabetes -- Alternative treatment -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/3077 , vital:28252
- Description: Diabetes mellitus is a chronic physiological carbohydrate metabolic disorder with significant impact on the economy, quality of life and life expectancy in South Africa. Herbal medicine has become the alternative therapy in the management of this disease. However, their safety and effectiveness have not been investigated. To address this, one of the plants used in Eastern Cape Province, South Africa, Bulbine abyssinica A. Rich (Asphodelaceae), was evaluated. Bulbine abyssinica is one of the species used in the management of diabetes mellitus. This plant was mentioned during an ethnobotanical survey conducted in Nkonkobe municipality of the Eastern Cape Province. Though a decoction prepared from the whole plant is used in the treatment of diabetes mellitus, the mechanism of action and its safety has not been elucidated. Thus, this research work was designed to contribute to the understanding of the possible mechanism of action of B. abyssinica as an antidiabetic medicinal plant and its toxic potentials to the users. The aqueous extract exhibited remarkable inhibitory activity onα-amylase (estimated inhibitory concentration (IC)50 value of 3.28 μg/ml), while the acetone extract exhibited weak inhibitory activity. The acetone extract exhibited notable α-glucosidase inhibitory activity (IC50 value of 4.27 μg/ml) while aqueous extract had significantly weak activity. The Lineweaver-Burk double reciprocal plots revealed that the aqueous extract exerts noncompetitive inhibition on the α-amylase activity while the acetone extract exerts a near competitive inhibitory pattern on the α-glucosidase activity. The extracts from the plant possessed high free radical scavenging activities, with acetone extract exhibiting the highest activities in all assay models used except with ferric reducing power and nitric oxide (NO) scavenging ability. The aqueous extract exhibited the highest ferric reducing power and nitric oxide radical mopping strength while the essential oil exhibited the highest scavenging activities with 1,1-diphenyl-2-picrylhydrazyl (DPPH) and relatively high ferric reducing power and nitric oxide scavenging ability. The acetone extract and the essential oil of this species exhibited higher albumin denaturation inhibition than the aqueous extract while the latter showed the greatest membrane lysis protection. The essential oil, acetone and aqueous extracts from this plant significantly inhibited the growth of Shigelle flexneri, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis. Klebsiella pneumonia, Proteus vulgaris and Streptococcus pyogens growth were inhibited by acetone and aqueous extracts. The essential oil also showed inhibitory activity against Proteus vulgaris. However, the extracts were active against the growth of only three fungi species. The essential oil showed significant inhibitory activity against Trichophyton rubrum. The aqueous extract inhibited the growth of Microsporum gypseum while the acetone extract was active against Microsporum canis, and Microsporum gypseum. The carbohydrate, crude fibre, moisture, ash, crude protein and crude fat of approximately 74.8 percent, 8.9 percent, 8.8 percent, 8 percent, 7.7 percent and 0.6 percent, respectively, were detected in this plant. The species is characterized by moderate levels of oxalates, phytic acids, Vitamin A, Vitamin C and Vitamin E. Potassium and calcium were present in highest levels, while magnesium, iron, sodium, aluminium and phosphorus were moderately present. Manganese, zinc and copper where in low amounts. These vitamins and mineral elements were within their recommended daily allowance (RDA) in humans. The investigation also revealed appreciable amounts of total phenols, flavonoids, flavanols, proanthocyanidins and alkaloids in both acetone and aqueous extracts while saponins and tannins were in trace amounts. The essential oil was characterized by large quantities of terpenes (91.9 percent) and small fraction of esters (8.01 percent).
- Full Text:
- Date Issued: 2016
Exploration of Nahoon beach milieu for lignocellulose degrading bacteria and optimizing fermentation conditions for holocellulase production by selected strains
- Authors: Fatokun, Evelyn
- Date: 2016
- Subjects: Lignocellulose Lignocellulose -- Biodegradation Water -- Purification -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/1529 , vital:27413
- Description: A significant trend in the modern day industrial biotechnology is the utilization and application of renewable resources, and ecofriendly approach to industrial processes and waste management. As a consequence thereof, the biotechnology of holocellulases: cellulase and xylanase and, enzymatic hydrolysis of renewable and abundant lignocellulosic biomass to energy and value added products are rapidly increasing; hence, cost effective enzyme system is imperative. In that context, exploration of microbiota for strains and enzymes with novel industrial properties is vital for efficient and commercially viable enzyme biotechnology. Consequent on the complex characteristics of high salinity, variable pressure, temperature and nutritional conditions, bacterial strains from the marine environment are equipped with enzyme machinery of industrial importance for adaptation and survival. In this study, bacterial strains were isolated form Nahoon beach and optimized for holocellulase production. Three isolates selected for lignocellulolytic potential were identified by 16S ribosomal deoxyribonucleic acid (rDNA) sequence analysis. Isolate FS1k had 98 percent similarity with Streptomyces albidoflavus strain AIH12, was designated as Streptomyces albidoflavus strain SAMRC-UFH5 and deposited in the GenBank with accession number KU171373. Similarly, isolates CS14b and CS22d with respective percentage similarity of 98 and 99 (percent) with Bacillus cereus strains and Streptomyces sp. strain WMMB251 were named Bacillus cereus strain SAMRC-UFH9 and Streptomyces sp. strain SAMRC-UFH6; and were deposited in the GenBank with accession number KX524510 and KU171374 respectively. Optimal pH, temperature and agitation speed for cellulase production by S. albidoflavus strain SAMRC-UFH5, and B. cereus strain SAMRC-UFH9 were 6 and 7; 40 and 30 (°C); and 100 and 150 (rpm) respectively; while xylanase production was optimal at pH, temperature and agitation speed of 8 and 7; 40 and 30 (°C); and 150 and 50 (rpm) respectively. Maximum cellulase activity of 0.26 and 0.061(U/mL) by S. albidoflavus strain SAMRC-UFH5 and B. cereus strain SAMRC-UFH9 were attained at 60 h respectively, while maximal xylanase activity of 18.54 and 16.6 (U/mL) was produced by S. albidoflavus strain SAMRC-UFH5 and B. cereus strain SAMRC-UFH9 at 48 h and 60 h respectively. Furthermore, xylanase production by S. albidoflavus strain SAMRC-UFH5 and B. cereus strain SAMRC-UFH9 was maximally induced by wheat straw and xylan respectively, while cellulase production was best induced by mannose and carboxymethyl cellulose respectively. On the other hand, cellulase and xylanase production by Streptomyces sp. strain SAMRC-UFH6 was optimal at pH, temperature and agitation speed of 7 and 8, 40 °C and 100 rpm, respectively. Highest production of cellulase and xylanase was attained at 84 and 60 h with respective activity of 0.065 and 6.34 (U/mL). In addition, cellulase and xylanase production by the strain was best induced by beechwood xylan. Moreover, xylanase produced by Streptomyces sp. strain SAMRC-UFH6 at optimal conditions was characterized by optimal pH and temperature of 8 and 80-90 °C respectively; retaining over 70 percent activity at pH 5-10 after 1 h and 60 percent of initial activity at 90 °C after 90 min of incubation. In all, optimization improved cellulase and xylanase production yields, being 40 and 95.5, 10.89 and 72.17, and 10 and 115- fold increase by S. albidoflavus strain SAMRC-UFH5, B. cereus strain SAMRC-UFH9 and Streptomyces sp. SAMRC-UFH6 respectively. The results of this study suggest that the marine bacterial strains are resource for holocellulase with industrial applications.
- Full Text:
- Date Issued: 2016
- Authors: Fatokun, Evelyn
- Date: 2016
- Subjects: Lignocellulose Lignocellulose -- Biodegradation Water -- Purification -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/1529 , vital:27413
- Description: A significant trend in the modern day industrial biotechnology is the utilization and application of renewable resources, and ecofriendly approach to industrial processes and waste management. As a consequence thereof, the biotechnology of holocellulases: cellulase and xylanase and, enzymatic hydrolysis of renewable and abundant lignocellulosic biomass to energy and value added products are rapidly increasing; hence, cost effective enzyme system is imperative. In that context, exploration of microbiota for strains and enzymes with novel industrial properties is vital for efficient and commercially viable enzyme biotechnology. Consequent on the complex characteristics of high salinity, variable pressure, temperature and nutritional conditions, bacterial strains from the marine environment are equipped with enzyme machinery of industrial importance for adaptation and survival. In this study, bacterial strains were isolated form Nahoon beach and optimized for holocellulase production. Three isolates selected for lignocellulolytic potential were identified by 16S ribosomal deoxyribonucleic acid (rDNA) sequence analysis. Isolate FS1k had 98 percent similarity with Streptomyces albidoflavus strain AIH12, was designated as Streptomyces albidoflavus strain SAMRC-UFH5 and deposited in the GenBank with accession number KU171373. Similarly, isolates CS14b and CS22d with respective percentage similarity of 98 and 99 (percent) with Bacillus cereus strains and Streptomyces sp. strain WMMB251 were named Bacillus cereus strain SAMRC-UFH9 and Streptomyces sp. strain SAMRC-UFH6; and were deposited in the GenBank with accession number KX524510 and KU171374 respectively. Optimal pH, temperature and agitation speed for cellulase production by S. albidoflavus strain SAMRC-UFH5, and B. cereus strain SAMRC-UFH9 were 6 and 7; 40 and 30 (°C); and 100 and 150 (rpm) respectively; while xylanase production was optimal at pH, temperature and agitation speed of 8 and 7; 40 and 30 (°C); and 150 and 50 (rpm) respectively. Maximum cellulase activity of 0.26 and 0.061(U/mL) by S. albidoflavus strain SAMRC-UFH5 and B. cereus strain SAMRC-UFH9 were attained at 60 h respectively, while maximal xylanase activity of 18.54 and 16.6 (U/mL) was produced by S. albidoflavus strain SAMRC-UFH5 and B. cereus strain SAMRC-UFH9 at 48 h and 60 h respectively. Furthermore, xylanase production by S. albidoflavus strain SAMRC-UFH5 and B. cereus strain SAMRC-UFH9 was maximally induced by wheat straw and xylan respectively, while cellulase production was best induced by mannose and carboxymethyl cellulose respectively. On the other hand, cellulase and xylanase production by Streptomyces sp. strain SAMRC-UFH6 was optimal at pH, temperature and agitation speed of 7 and 8, 40 °C and 100 rpm, respectively. Highest production of cellulase and xylanase was attained at 84 and 60 h with respective activity of 0.065 and 6.34 (U/mL). In addition, cellulase and xylanase production by the strain was best induced by beechwood xylan. Moreover, xylanase produced by Streptomyces sp. strain SAMRC-UFH6 at optimal conditions was characterized by optimal pH and temperature of 8 and 80-90 °C respectively; retaining over 70 percent activity at pH 5-10 after 1 h and 60 percent of initial activity at 90 °C after 90 min of incubation. In all, optimization improved cellulase and xylanase production yields, being 40 and 95.5, 10.89 and 72.17, and 10 and 115- fold increase by S. albidoflavus strain SAMRC-UFH5, B. cereus strain SAMRC-UFH9 and Streptomyces sp. SAMRC-UFH6 respectively. The results of this study suggest that the marine bacterial strains are resource for holocellulase with industrial applications.
- Full Text:
- Date Issued: 2016
Farm to abattoir conditions and their subsequent effects on behavioural and physiological changes and the quality of beef from extensively-reared Nguni and non-descript steers
- Authors: Njisane, Yonela Zifikile
- Date: 2016
- Subjects: Nguni cattle Beef cattle breeds Beef -- Quality -- South Africa , Slaughtering and slaughter-houses -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/3143 , vital:28324
- Description: The main objective of the study was to determine the effect of farm to abattoir environmental conditions and their subsequent effects on behavioural and physiological responses, as well as the quality of meat from Nguni (NG) and non-descript (ND) beef steers reared extensively on natural pastures. The forty 16 – 19 months old steers (20 ND and 20 NG) used in the current study were grouped together, medically treated, allowed three weeks acclimatizing period and were used in this trial over a four-month period. The weather and periodical variations influence on time budgets and body weights of these steers were determined. Furthermore, the effects of on-farm successive handling on behavioural scores and physiological responses of the same steers were determined. Later in the trial, some pre-slaughter effects on response-behaviour, bleed-out times and selected blood physiological responses were determined. Finally, the effect of genotype, muscle type, lairage duration, slaughter order and stress responsiveness on pH24, temperature, colour (L*, a*, b*, C, HA), thawing (TL) and cooking (CL) losses and Warner Bratzler Shear Force (WBSF) of the meat harvested from the same steers were determined. The daily time budgets of steers in natural pastures changed with temperature, humidity, observation week and time of the day. The grazing behaviour was observed throughout the observation days (> 37 percent); though it was reduced (26.9±2.64 percent) on days with higher temperatures and low humidity. Higher proportions of drinking (1.5±1.04 percent) and standing (20.8±4.63 percent) behaviours prolonged in such weather conditions, which were mostly during midday. The avoidance-related behaviour of the steers during handling varies, with the steers showing more avoidance and aggression in other weeks than some. These variations could however be traced back to the events of that particular day/time of handling. Only Weighing Box (WBS) and stepping (SS) scores differed (P<0.05) with genotype; with more calm NG steers (> 40 percent) and not kicking than the ND steers that were more vocal (20–60 percent) and kicking (> 5 percent). In addition, the weekly behavioural responses were reflected (P<0.05) in the measured cortisol, glucose and lactate. However, regardless of the prominent negative behaviour seen over time, the levels of the measured blood constituents continued to drop. Furthermore, steers of different genotypes displayed similar (P>0.05) response to the identical pre-slaughter conditions they were exposed to. However, steers that were Transport Group 1 (TG1) showed more avoidance (63.2 percent) pre-slaughter than those in TG2 (23.9 percent). Furthermore, all the steers that were in slaughter Group 2 (SG2) showed less avoidance behaviour than those in other groups. Vocalization was observed only for ND steers (5 percent), in TG1 and SG2. Some connections between the observed pre-slaughter activities and some behavioural and physiological changes of these steers were established; with TG1 and SG1 steers showing higher cortisol (140±14.50 and 175.9±17.24 nmol/L, respectively) and lactate (12.4±0.83 and 13.5±1.12 mmolL) levels than the other groups. Lastly, the muscle type, genotype, lairage duration, slaughter order and stress responsiveness have an effect on some meat quality characteristics of the two genotypes; with the L. dorsi muscle having highest WBSF (38.0±1.35N) than the Superficial pectoral muscle (Brisket muscle) (30.7±1.35N). Additionally, steers lairaged for a shorter time produced a L. dorsi with higher WBSF (41.6±2.34N) and a Brisket with lower TL (2.7±0.24 percent). It can therefore be concluded that the conditions and activities at the farm, during transportation, lairaging and slaughter at the abattoir have an influence on some behavioural and physiological changes and the quality of beef harvested from the Nguni and non-descript steers that were extensively-reared in natural pastures. However, the relationship patterns between these different conditions are not clear.
- Full Text:
- Date Issued: 2016
- Authors: Njisane, Yonela Zifikile
- Date: 2016
- Subjects: Nguni cattle Beef cattle breeds Beef -- Quality -- South Africa , Slaughtering and slaughter-houses -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/3143 , vital:28324
- Description: The main objective of the study was to determine the effect of farm to abattoir environmental conditions and their subsequent effects on behavioural and physiological responses, as well as the quality of meat from Nguni (NG) and non-descript (ND) beef steers reared extensively on natural pastures. The forty 16 – 19 months old steers (20 ND and 20 NG) used in the current study were grouped together, medically treated, allowed three weeks acclimatizing period and were used in this trial over a four-month period. The weather and periodical variations influence on time budgets and body weights of these steers were determined. Furthermore, the effects of on-farm successive handling on behavioural scores and physiological responses of the same steers were determined. Later in the trial, some pre-slaughter effects on response-behaviour, bleed-out times and selected blood physiological responses were determined. Finally, the effect of genotype, muscle type, lairage duration, slaughter order and stress responsiveness on pH24, temperature, colour (L*, a*, b*, C, HA), thawing (TL) and cooking (CL) losses and Warner Bratzler Shear Force (WBSF) of the meat harvested from the same steers were determined. The daily time budgets of steers in natural pastures changed with temperature, humidity, observation week and time of the day. The grazing behaviour was observed throughout the observation days (> 37 percent); though it was reduced (26.9±2.64 percent) on days with higher temperatures and low humidity. Higher proportions of drinking (1.5±1.04 percent) and standing (20.8±4.63 percent) behaviours prolonged in such weather conditions, which were mostly during midday. The avoidance-related behaviour of the steers during handling varies, with the steers showing more avoidance and aggression in other weeks than some. These variations could however be traced back to the events of that particular day/time of handling. Only Weighing Box (WBS) and stepping (SS) scores differed (P<0.05) with genotype; with more calm NG steers (> 40 percent) and not kicking than the ND steers that were more vocal (20–60 percent) and kicking (> 5 percent). In addition, the weekly behavioural responses were reflected (P<0.05) in the measured cortisol, glucose and lactate. However, regardless of the prominent negative behaviour seen over time, the levels of the measured blood constituents continued to drop. Furthermore, steers of different genotypes displayed similar (P>0.05) response to the identical pre-slaughter conditions they were exposed to. However, steers that were Transport Group 1 (TG1) showed more avoidance (63.2 percent) pre-slaughter than those in TG2 (23.9 percent). Furthermore, all the steers that were in slaughter Group 2 (SG2) showed less avoidance behaviour than those in other groups. Vocalization was observed only for ND steers (5 percent), in TG1 and SG2. Some connections between the observed pre-slaughter activities and some behavioural and physiological changes of these steers were established; with TG1 and SG1 steers showing higher cortisol (140±14.50 and 175.9±17.24 nmol/L, respectively) and lactate (12.4±0.83 and 13.5±1.12 mmolL) levels than the other groups. Lastly, the muscle type, genotype, lairage duration, slaughter order and stress responsiveness have an effect on some meat quality characteristics of the two genotypes; with the L. dorsi muscle having highest WBSF (38.0±1.35N) than the Superficial pectoral muscle (Brisket muscle) (30.7±1.35N). Additionally, steers lairaged for a shorter time produced a L. dorsi with higher WBSF (41.6±2.34N) and a Brisket with lower TL (2.7±0.24 percent). It can therefore be concluded that the conditions and activities at the farm, during transportation, lairaging and slaughter at the abattoir have an influence on some behavioural and physiological changes and the quality of beef harvested from the Nguni and non-descript steers that were extensively-reared in natural pastures. However, the relationship patterns between these different conditions are not clear.
- Full Text:
- Date Issued: 2016
Indigenous forests level of deforestation, forest dependency and factors determining willingness to participate in indigenous forest conservation: evidence from resettled farmers of Shamva, Zimbabwe
- Authors: Chivheya, Renias V
- Date: 2016
- Subjects: Forest conservation -- Zimbabwe Forests and forestry -- Economic aspects -- Zimbabwe Deforestation -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/2370 , vital:27786
- Description: This study first explored the rate of forest deforestation in Shamva resettlement areas. It then identified and estimated the extent to which these resettled farmers depend on forest for their livelihoods. Evaluation of farmer perceptions on management issues and willingness to participate in indigenous forest conservation and the socio-economic and institutional factors which affect their willingness to participate were also done. Finally the study sought to identify incentives for forests conservation. The study was conducted in Shamva district in Mashonaland Central province. And the respondents were stratified into three groups: A1, A2 and Old resettlement models. The three models differ on how they were implemented and supported which might render them to have different deforestation rates, livelihood strategies and forest dependency. A total of 247 respondents were surveyed, consisting of 98 A1 farmers, 50 A2 farmers and 99 Old resettled farmers. The data was collected using GIS and remote sensing, structured questionnaire interviews and direct observation. The data was analysed using descriptive analysis, KAP analytic framework and binary logistic regression analysis. The land cover/changes results revealed that both deforestation and afforestation are taking place in Shamva resettlement. Woodland and bushland were decreasing, croplands were also decreasing. However woodland dense and grasslands were increasing. Deforestation was found to be as a result of the resettled farmers’ livelihood strategies which were found to be diverse and agriculture being dominant in all models. All the farmers depended on the forest but at varying levels of 19 percent for Old and 14 percent forA1 and 0.02 percent for A2 resettle farmers. 84 percent of the interviewed farmers however, indicated that they are willing to conserve forest with A1 farmers being the highest followed by A2 86 percent and lastly Old resettled farmers at 76.8 percent. Results of the binary regression model revealed that the significant factors which explain willingness to participate in indigenous forest conservation are age, marital status, education, gender, institution, culture and belief, employment and household size. The highest preferred incentive was the provision of free seedlings and the lowest was out grower scheme. The study recommends that GIS and remote sensing should be used to monitor deforestation, off farm projects be encouraged, exotic and indigenous trees be promoted and forest conservation education be promoted in resettlement areas.
- Full Text:
- Date Issued: 2016
- Authors: Chivheya, Renias V
- Date: 2016
- Subjects: Forest conservation -- Zimbabwe Forests and forestry -- Economic aspects -- Zimbabwe Deforestation -- Zimbabwe
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10353/2370 , vital:27786
- Description: This study first explored the rate of forest deforestation in Shamva resettlement areas. It then identified and estimated the extent to which these resettled farmers depend on forest for their livelihoods. Evaluation of farmer perceptions on management issues and willingness to participate in indigenous forest conservation and the socio-economic and institutional factors which affect their willingness to participate were also done. Finally the study sought to identify incentives for forests conservation. The study was conducted in Shamva district in Mashonaland Central province. And the respondents were stratified into three groups: A1, A2 and Old resettlement models. The three models differ on how they were implemented and supported which might render them to have different deforestation rates, livelihood strategies and forest dependency. A total of 247 respondents were surveyed, consisting of 98 A1 farmers, 50 A2 farmers and 99 Old resettled farmers. The data was collected using GIS and remote sensing, structured questionnaire interviews and direct observation. The data was analysed using descriptive analysis, KAP analytic framework and binary logistic regression analysis. The land cover/changes results revealed that both deforestation and afforestation are taking place in Shamva resettlement. Woodland and bushland were decreasing, croplands were also decreasing. However woodland dense and grasslands were increasing. Deforestation was found to be as a result of the resettled farmers’ livelihood strategies which were found to be diverse and agriculture being dominant in all models. All the farmers depended on the forest but at varying levels of 19 percent for Old and 14 percent forA1 and 0.02 percent for A2 resettle farmers. 84 percent of the interviewed farmers however, indicated that they are willing to conserve forest with A1 farmers being the highest followed by A2 86 percent and lastly Old resettled farmers at 76.8 percent. Results of the binary regression model revealed that the significant factors which explain willingness to participate in indigenous forest conservation are age, marital status, education, gender, institution, culture and belief, employment and household size. The highest preferred incentive was the provision of free seedlings and the lowest was out grower scheme. The study recommends that GIS and remote sensing should be used to monitor deforestation, off farm projects be encouraged, exotic and indigenous trees be promoted and forest conservation education be promoted in resettlement areas.
- Full Text:
- Date Issued: 2016
Mechanism and synchronicity of wheat (Triticum aestivum) resistance to leaf rust (Puccinia triticina) and Russian wheat aphid (Duiraphis noxia) SA1
- Authors: Njom, Henry Akum
- Date: 2016
- Subjects: Wheat -- Disease and pest resistance Bacterial diseases of plants Russian wheat aphid
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/2700 , vital:28056
- Description: Wheat (Triticum aestivum and T. Durum) is an extremely important agronomic crop produced worldwide. Wheat consumption has doubled in the last 30 years with approximately 600 million tons consumed per annum. According to the International Maize and Wheat Improvement Center, worldwide wheat demand will increase over 40 percent by 2020, while land as well as resources available for the production will decrease significantly if the current trend prevails. The wheat industry is challenged with abiotic and biotic stressors that lead to reduction in crop yields. Increase knowledge of wheat’s biochemical constitution and functional biology is of paramount importance to improve wheat so as to meet with this demand. Pesticides and fungicides are being used to control biotic stress imposed by insect pest and fungi pathogens but these chemicals pose a risk to the environment and human health. To this effect, there is re-evaluation of pesticides currently in use by the Environmental Protection Agency, via mandates of the 1996 Food Quality Protection Act and those with higher perceived risks are banned. Genetic resistance is now a more environmental friendly and effective method of controlling insect pest and rust diseases of wheat than the costly spraying with pesticides and fungicides. Although, resistant cultivars effectively prevent current prevailing pathotypes of leaf rust and biotypes of Russian wheat aphid from attacking wheat, new pathotypes and biotypes of the pathogen/pest may develop and infect resistant cultivars. Therefore, breeders are continually searching for new sources of resistance. Proteomic approaches can be utilised to ascertain target enzymes and proteins from resistant lines that could be utilised to augment the natural tolerance of agronomically favourable varieties of wheat. With this ultimate goal in mind, the aim of this study was to elucidate the mechanism and synchronicity of wheat resistance to leaf rust (Puccinia triticina) and Russian wheat aphid (Duiraphis noxia) SA1. To determine the resistance mechanism of the wheat cultivars to leaf rust infection and Russian wheat aphid infestation, a proteomics approach using two-dimensional gel electrophoresis was used in order to determine the effect of RWA SA1 on the wheat cultivars proteome. Differentially expressed proteins that were up or down regulated (appearing or disappearing) were identified using PDQuestTM Basic 2-DE Gel analysis software. Proteins bands of interest were in-gel trypsin digested as per the protocol described in Schevchenko et al. (2007) and analysed using a Dionex Ultimate 3000 RSLC system coupled to an AB Sciex 6600 TripleTOF mass spectrometer. Protein pilot v5 using Paragon search engine (AB Sciex) was used for comparison of the obtained MS/MS spectra with a custom database containing sequences of Puccinia triticina (Uniprot Swissprot), Triticum aestivum (Uniprot TrEMBL) and Russian wheat aphid (Uniprot TrEMBL) as well as a list of sequences from common contaminating proteins. Proteins with a threshold of ≥99.9 percent confidence were reported. A total of 72 proteins were putatively identified from the 37 protein spots excised originating from either leaf rust or Russian wheat aphid experiments. Sixty-three of these proteins were associated with wheat response to stress imposed by RWA SA1 feeding while 39 were associated with infection by Puccinia triticina. Several enzymes involved in the Calvin cycle, electron transport and ATP synthesis were observed to be differentially regulated suggesting greater metabolic requirements in the wheat plants following aphid infestation and leaf rust infection. Proteins directly associated with photosynthesis were also differentially regulated following RWA SA1 infestation and P.
- Full Text:
- Date Issued: 2016
- Authors: Njom, Henry Akum
- Date: 2016
- Subjects: Wheat -- Disease and pest resistance Bacterial diseases of plants Russian wheat aphid
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/2700 , vital:28056
- Description: Wheat (Triticum aestivum and T. Durum) is an extremely important agronomic crop produced worldwide. Wheat consumption has doubled in the last 30 years with approximately 600 million tons consumed per annum. According to the International Maize and Wheat Improvement Center, worldwide wheat demand will increase over 40 percent by 2020, while land as well as resources available for the production will decrease significantly if the current trend prevails. The wheat industry is challenged with abiotic and biotic stressors that lead to reduction in crop yields. Increase knowledge of wheat’s biochemical constitution and functional biology is of paramount importance to improve wheat so as to meet with this demand. Pesticides and fungicides are being used to control biotic stress imposed by insect pest and fungi pathogens but these chemicals pose a risk to the environment and human health. To this effect, there is re-evaluation of pesticides currently in use by the Environmental Protection Agency, via mandates of the 1996 Food Quality Protection Act and those with higher perceived risks are banned. Genetic resistance is now a more environmental friendly and effective method of controlling insect pest and rust diseases of wheat than the costly spraying with pesticides and fungicides. Although, resistant cultivars effectively prevent current prevailing pathotypes of leaf rust and biotypes of Russian wheat aphid from attacking wheat, new pathotypes and biotypes of the pathogen/pest may develop and infect resistant cultivars. Therefore, breeders are continually searching for new sources of resistance. Proteomic approaches can be utilised to ascertain target enzymes and proteins from resistant lines that could be utilised to augment the natural tolerance of agronomically favourable varieties of wheat. With this ultimate goal in mind, the aim of this study was to elucidate the mechanism and synchronicity of wheat resistance to leaf rust (Puccinia triticina) and Russian wheat aphid (Duiraphis noxia) SA1. To determine the resistance mechanism of the wheat cultivars to leaf rust infection and Russian wheat aphid infestation, a proteomics approach using two-dimensional gel electrophoresis was used in order to determine the effect of RWA SA1 on the wheat cultivars proteome. Differentially expressed proteins that were up or down regulated (appearing or disappearing) were identified using PDQuestTM Basic 2-DE Gel analysis software. Proteins bands of interest were in-gel trypsin digested as per the protocol described in Schevchenko et al. (2007) and analysed using a Dionex Ultimate 3000 RSLC system coupled to an AB Sciex 6600 TripleTOF mass spectrometer. Protein pilot v5 using Paragon search engine (AB Sciex) was used for comparison of the obtained MS/MS spectra with a custom database containing sequences of Puccinia triticina (Uniprot Swissprot), Triticum aestivum (Uniprot TrEMBL) and Russian wheat aphid (Uniprot TrEMBL) as well as a list of sequences from common contaminating proteins. Proteins with a threshold of ≥99.9 percent confidence were reported. A total of 72 proteins were putatively identified from the 37 protein spots excised originating from either leaf rust or Russian wheat aphid experiments. Sixty-three of these proteins were associated with wheat response to stress imposed by RWA SA1 feeding while 39 were associated with infection by Puccinia triticina. Several enzymes involved in the Calvin cycle, electron transport and ATP synthesis were observed to be differentially regulated suggesting greater metabolic requirements in the wheat plants following aphid infestation and leaf rust infection. Proteins directly associated with photosynthesis were also differentially regulated following RWA SA1 infestation and P.
- Full Text:
- Date Issued: 2016
Pharmacological studies of Foeniculum Vulgare (Mill.) and Lippia Javanica (Burm.F.) spreng. used as spices in Nkonkobe Municipality of the Eastern Cape Province, South Africa
- Asowata-Ayodele, Abiola Mojisola
- Authors: Asowata-Ayodele, Abiola Mojisola
- Date: 2016
- Subjects: Medicinal plants -- South Africa -- Eastern Cape Fennel -- Utilization -- South Africa -- Eastern Cape Ethnopharmacology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/2777 , vital:28085
- Description: Spices are of great importance in the indigenous culinary and traditional medicine systems of the people of Nkonkobe Municipality of the Eastern Cape, South Africa. The present investigation evaluated the ethnopharmacological potentials of two indigenous South African spices- Foeniculum vulgare and Lippia javanica. The pharmacological investigations on these two plant species include ultra-morphology, nutrient and mineral analysis, evaluation of the essential oil, phytochemical and antioxidant assays, antimicrobial, anti-inflammatory as well as anti-urolithiatic assay of the acetone and aqueous extracts of the two plants. The species were selected for study as the most cited plants after an ethnobotanical survey conducted on the indigenous knowledge of plants used as spices and medicine in Nkonkobe Municipality, Eastern Cape of South Africa. Among the plants cited Foeniculum vulgare(Apiaceae) and Lippia javanica (Verbenaceae) stood out as the most commonly used spices. Others were members of the families; Solanaceae, Apiaceae, Amaryllidaceae, Amaranthaceae and Lamiaceae. Ultra-morphological studies conducted on the leaves of the two selected plants using scanning electron microscope revealed the presence of non-glandular and glandular trichomes, stomata and crystals. The leaf surfaces of these herbs may serve as secretory sites where aromatic secondary metabolites are produced. Analyses of the proximate, mineral, vitamin and anti-nutrients contents of these two spices showed that both species are good sources of these phytochemicals and may be used to enrich the human diet. Lippia javanica possesses lower lipid (0.50 percent), fibre (5 percent) and carbohydrate (64.96 percent) contents than Foeniculum vulgare. On the other hand, protein (20.54 percent), ash (11.60 percent) and moisture content (11.69 percent) were higher in Foeniculum vulgare than in Lippia javanica. Foeniculum vulgare showed higher N (3286 mg/100g), Mg (386.7 mg/100g), K (3187 mg/100g) and Na (1383 mg/100g) content while Lippia javanica was higher in Ca (1833 mg/100g), Zn (4.7 mg/100g), Cu (0.9 mg/100g) and Fe (78.4 mg/100g). Vitamins Aand E were also higher in Lippia javanica (1.31 mg/100g; 2.52 mg/100g) while Foeniculum vulgare (0.45 mg/100g) had higher vitamin C content. No significant differences were observed in the phytate, oxalate and tannin contents of the two spices, but saponin and cyanide were significantly lower in Lippia javanica (268.5 mg/100g; 8.45 mg/100g) than in Foeniculum vulgare (1855 mg/100g; 10.5 mg/100g) Evaluation of the essential oil component, cytotoxicity and antimicrobial activities of both fresh and dried leaves of Lippia javanica and Foeniculum vulgare revealed that the dried samples yielded more oil and also contain more chemical than the fresh samples of both plants. The overall antimicrobial activity evaluated using susceptibility and microdilution assays revealed that the oils of F. vulgare and L. javanica exhibited high antifungal and antibacterial activity, compared to the reference drugs. In addition, essential oil from fresh leaves of both spices was less toxic compared to the oil from the dried leaves. Polyphenolic evaluation of the aqueous and acetone extracts of the plants revealed that the acetone extract had higher phenol, flavanol, flavonoid and proanthocyanidin contents than the aqueous extracts. The total phenolic content of acetone and aqueous extracts were 4.49 ± 0.411 mg/g and 3.73 ± 0.498 mg/g tannic acid equivalent (TAE) respectively for Lippia javanica. The same trend was also observed in Foeniculum vulgare with total phenolic content of acetone and aqueous extracts were 4.22 ± 0.325 mg/g and 4.17 ± 0.651 mg/g tannic acid equivalent (TAE) respectively. Further assessment of the antioxidant activity of the solvent extracts revealed that both plants exhibited promising free radical scavenging potentials against 1,1 diphenyl-2-picrylhydrazyl (DPPH), 2, 2’-azino-bis(3- ethylbenzthiazoline-6-sulfonic acid (ABTS), reducing power, lipid peroxidation, nitric oxide, phosphomolybdate and hydrogen peroxide. Antimicrobial activities of the acetone and aqueous extracts of the two plants revealed moderate antibacterial and antifungal activities. They inhibited the growth of Microsporium canis and Trichophyton rubrum that were not susceptible to the standard antifungal drug used as control.
- Full Text:
- Date Issued: 2016
- Authors: Asowata-Ayodele, Abiola Mojisola
- Date: 2016
- Subjects: Medicinal plants -- South Africa -- Eastern Cape Fennel -- Utilization -- South Africa -- Eastern Cape Ethnopharmacology -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/2777 , vital:28085
- Description: Spices are of great importance in the indigenous culinary and traditional medicine systems of the people of Nkonkobe Municipality of the Eastern Cape, South Africa. The present investigation evaluated the ethnopharmacological potentials of two indigenous South African spices- Foeniculum vulgare and Lippia javanica. The pharmacological investigations on these two plant species include ultra-morphology, nutrient and mineral analysis, evaluation of the essential oil, phytochemical and antioxidant assays, antimicrobial, anti-inflammatory as well as anti-urolithiatic assay of the acetone and aqueous extracts of the two plants. The species were selected for study as the most cited plants after an ethnobotanical survey conducted on the indigenous knowledge of plants used as spices and medicine in Nkonkobe Municipality, Eastern Cape of South Africa. Among the plants cited Foeniculum vulgare(Apiaceae) and Lippia javanica (Verbenaceae) stood out as the most commonly used spices. Others were members of the families; Solanaceae, Apiaceae, Amaryllidaceae, Amaranthaceae and Lamiaceae. Ultra-morphological studies conducted on the leaves of the two selected plants using scanning electron microscope revealed the presence of non-glandular and glandular trichomes, stomata and crystals. The leaf surfaces of these herbs may serve as secretory sites where aromatic secondary metabolites are produced. Analyses of the proximate, mineral, vitamin and anti-nutrients contents of these two spices showed that both species are good sources of these phytochemicals and may be used to enrich the human diet. Lippia javanica possesses lower lipid (0.50 percent), fibre (5 percent) and carbohydrate (64.96 percent) contents than Foeniculum vulgare. On the other hand, protein (20.54 percent), ash (11.60 percent) and moisture content (11.69 percent) were higher in Foeniculum vulgare than in Lippia javanica. Foeniculum vulgare showed higher N (3286 mg/100g), Mg (386.7 mg/100g), K (3187 mg/100g) and Na (1383 mg/100g) content while Lippia javanica was higher in Ca (1833 mg/100g), Zn (4.7 mg/100g), Cu (0.9 mg/100g) and Fe (78.4 mg/100g). Vitamins Aand E were also higher in Lippia javanica (1.31 mg/100g; 2.52 mg/100g) while Foeniculum vulgare (0.45 mg/100g) had higher vitamin C content. No significant differences were observed in the phytate, oxalate and tannin contents of the two spices, but saponin and cyanide were significantly lower in Lippia javanica (268.5 mg/100g; 8.45 mg/100g) than in Foeniculum vulgare (1855 mg/100g; 10.5 mg/100g) Evaluation of the essential oil component, cytotoxicity and antimicrobial activities of both fresh and dried leaves of Lippia javanica and Foeniculum vulgare revealed that the dried samples yielded more oil and also contain more chemical than the fresh samples of both plants. The overall antimicrobial activity evaluated using susceptibility and microdilution assays revealed that the oils of F. vulgare and L. javanica exhibited high antifungal and antibacterial activity, compared to the reference drugs. In addition, essential oil from fresh leaves of both spices was less toxic compared to the oil from the dried leaves. Polyphenolic evaluation of the aqueous and acetone extracts of the plants revealed that the acetone extract had higher phenol, flavanol, flavonoid and proanthocyanidin contents than the aqueous extracts. The total phenolic content of acetone and aqueous extracts were 4.49 ± 0.411 mg/g and 3.73 ± 0.498 mg/g tannic acid equivalent (TAE) respectively for Lippia javanica. The same trend was also observed in Foeniculum vulgare with total phenolic content of acetone and aqueous extracts were 4.22 ± 0.325 mg/g and 4.17 ± 0.651 mg/g tannic acid equivalent (TAE) respectively. Further assessment of the antioxidant activity of the solvent extracts revealed that both plants exhibited promising free radical scavenging potentials against 1,1 diphenyl-2-picrylhydrazyl (DPPH), 2, 2’-azino-bis(3- ethylbenzthiazoline-6-sulfonic acid (ABTS), reducing power, lipid peroxidation, nitric oxide, phosphomolybdate and hydrogen peroxide. Antimicrobial activities of the acetone and aqueous extracts of the two plants revealed moderate antibacterial and antifungal activities. They inhibited the growth of Microsporium canis and Trichophyton rubrum that were not susceptible to the standard antifungal drug used as control.
- Full Text:
- Date Issued: 2016
Preparation and application of plasmon metal enhanced titanium dioxide photocatalyst for the removal of organics in water
- Authors: Nyamukamba, Pardon
- Date: 2016
- Subjects: Water -- Purification -- Photocatalysis Titanium dioxide Water chemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/2765 , vital:28074
- Description: Advanced oxidation processes are capable of removing organic compounds that cannot be removed by conventional water treatment methods. Among the oxidation processes, photo-catalysis using titanium dioxide (TiO2) is a promising method but suffers from rapid electron-hole recombination rates and only absorbs UV light which is a small percentage (5 percent) of the total solar radiation. Therefore there is a need to reduce the recombination rates and also extend the absorption of the photo-catalyst into the visible region which constitutes 55 percent of the total solar radiation. The major aims of this study were to prepare plasmon metal decorated and doped TiO2 photo-catalysts immobilized on quartz substrates and test their photo-catalytic and antimicrobial activities. The effect of film thickness (loading) and use of different shapes of plasmon metal nanostructures was investigated. TiO2 thin films were prepared by a sputter coating technique while plasmon metal (Au & Ag)/carbon co-doped TiO2 by a simple sol gel process and plasmon metal films were prepared by the thermal evaporation technique. Different plasmon metal nanostructures (nanorods, dendrites, nanowires and spherical nanoparticles) were prepared using a wet chemical technique using sodium borohydride as the reducing agent. Nanocomposites of co-doped TiO2 photo-catalyst and plasmon elements of different proportions were also prepared. The prepared photo-catalysts were coated onto etched and MPTMS (3-Mercaptopropyl trimethoxysliane) treated quartz glass substrate which is a stable support favouring easy recovery. The prepared materials were characterized by XRD, HRTEM, TEM, HRSEM, FT-IR, SEM, PIXE and TGA while the doped TiO2 was characterized by XPS, BET, CHNS and Raman Spectroscopy. The effect of pH of solution, presence of other contaminants and salts in solution, initial concentration of the model pollutant and type of the plasmonic elements on the photocatalytic activity of TiO2 towards 4-(4-sulfophenylazo)-N,N-dimethyl aniline (methyl orange) were also investigated. The selected TiO2 photo-catalyst films were tested for antimicrobial properties. The effect of different types of plasmon elements on the antimicrobial activity of TiO2 against E. coli ATCC 3695 was evaluated under both sunlight and weak UV light. Under UV light, Ag showed the highest enhancement in photo-catalytic activity of TiO2 than Au and Cu. The photo-catalytic activity of TiO2 increased with an increase in Ag content to an optimum loading and then started to decrease with a further increase in loading. For Cu and Au, photo-activity activity increased with an increase in plasmon metal content. Under sunlight, Cu showed the highest enhancement of TiO2 photocatalytic compared to Ag and Au. The change in order of deposition showed that Au films enhanced the photo-activity better when they were deposited underneath rather than on top of TiO2 on quartz supports but Ag films performed better in enhancing photo-activity when they were deposited on top of TiO2. The use of bimetallic layers and three layer systems of different plasmon elements enhanced photo-catalytic activity better than the use of a monometallic layer. The presence of other organic contaminants and salts in solutions was found to reduce the photo-degradation of methyl orange due to preferential adsorption of other contaminants. When the pH was increased, the photocatalytic activity of TiO2 towards methyl orange was reduced. In antimicrobial studies, it was found that the plasmon elements greatly improved the antibacterial action of TiO2 against Escherichia coli ATCC 3695 in water and the best antibacterial action was observed with silver/carbon co-doped TiO2 photo-catalyst under sunlight The doped samples consisted of polydisperse nanoparticles which were found to be beneficial for photo-catalytic activity enhancement under sunlight.
- Full Text:
- Date Issued: 2016
- Authors: Nyamukamba, Pardon
- Date: 2016
- Subjects: Water -- Purification -- Photocatalysis Titanium dioxide Water chemistry
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/2765 , vital:28074
- Description: Advanced oxidation processes are capable of removing organic compounds that cannot be removed by conventional water treatment methods. Among the oxidation processes, photo-catalysis using titanium dioxide (TiO2) is a promising method but suffers from rapid electron-hole recombination rates and only absorbs UV light which is a small percentage (5 percent) of the total solar radiation. Therefore there is a need to reduce the recombination rates and also extend the absorption of the photo-catalyst into the visible region which constitutes 55 percent of the total solar radiation. The major aims of this study were to prepare plasmon metal decorated and doped TiO2 photo-catalysts immobilized on quartz substrates and test their photo-catalytic and antimicrobial activities. The effect of film thickness (loading) and use of different shapes of plasmon metal nanostructures was investigated. TiO2 thin films were prepared by a sputter coating technique while plasmon metal (Au & Ag)/carbon co-doped TiO2 by a simple sol gel process and plasmon metal films were prepared by the thermal evaporation technique. Different plasmon metal nanostructures (nanorods, dendrites, nanowires and spherical nanoparticles) were prepared using a wet chemical technique using sodium borohydride as the reducing agent. Nanocomposites of co-doped TiO2 photo-catalyst and plasmon elements of different proportions were also prepared. The prepared photo-catalysts were coated onto etched and MPTMS (3-Mercaptopropyl trimethoxysliane) treated quartz glass substrate which is a stable support favouring easy recovery. The prepared materials were characterized by XRD, HRTEM, TEM, HRSEM, FT-IR, SEM, PIXE and TGA while the doped TiO2 was characterized by XPS, BET, CHNS and Raman Spectroscopy. The effect of pH of solution, presence of other contaminants and salts in solution, initial concentration of the model pollutant and type of the plasmonic elements on the photocatalytic activity of TiO2 towards 4-(4-sulfophenylazo)-N,N-dimethyl aniline (methyl orange) were also investigated. The selected TiO2 photo-catalyst films were tested for antimicrobial properties. The effect of different types of plasmon elements on the antimicrobial activity of TiO2 against E. coli ATCC 3695 was evaluated under both sunlight and weak UV light. Under UV light, Ag showed the highest enhancement in photo-catalytic activity of TiO2 than Au and Cu. The photo-catalytic activity of TiO2 increased with an increase in Ag content to an optimum loading and then started to decrease with a further increase in loading. For Cu and Au, photo-activity activity increased with an increase in plasmon metal content. Under sunlight, Cu showed the highest enhancement of TiO2 photocatalytic compared to Ag and Au. The change in order of deposition showed that Au films enhanced the photo-activity better when they were deposited underneath rather than on top of TiO2 on quartz supports but Ag films performed better in enhancing photo-activity when they were deposited on top of TiO2. The use of bimetallic layers and three layer systems of different plasmon elements enhanced photo-catalytic activity better than the use of a monometallic layer. The presence of other organic contaminants and salts in solutions was found to reduce the photo-degradation of methyl orange due to preferential adsorption of other contaminants. When the pH was increased, the photocatalytic activity of TiO2 towards methyl orange was reduced. In antimicrobial studies, it was found that the plasmon elements greatly improved the antibacterial action of TiO2 against Escherichia coli ATCC 3695 in water and the best antibacterial action was observed with silver/carbon co-doped TiO2 photo-catalyst under sunlight The doped samples consisted of polydisperse nanoparticles which were found to be beneficial for photo-catalytic activity enhancement under sunlight.
- Full Text:
- Date Issued: 2016
Smallholder farmer's adoption decision-making processes in the utilisation of soil conservation practices in South Africa: the case of Qamata Irrigation Scheme, in the Eastern Cape
- Authors: David, Ighodaro Ikponmwosa
- Date: 2016
- Subjects: Qamata Irrigation Scheme (South Africa) Irrigation -- South Africa -- Eastern Cape Farm management -- South Africa -- Decision making , Farms, Small -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/1740 , vital:27554
- Description: The goal of this study was to determine the nature and factors influencing smallholder farmers in their adoption decision-making regarding the use of soil conservation practices introduced by extension practitioners in South Africa, using the case of farming at Qamata Irrigation Scheme, Eastern Cape. Using a central argument (thesis statement), the study argued that an adequate understanding and definition of smallholder farmers’ adoption decision-making process is very crucial to solving the problem of soil erosion/ degradation problem amongst smallholder farmers. Adopting the case study research design, information from 70 crop farmers (in a farmer focus group interviews) form the basis of the study. Basic models of analysis were the multiple, probit and logit, as well as the binary logistic regression analyses. According to the empirical results, perception was found very relevant in adoption decision-making, interacting positively and significantly with eight of the seventeen adoption variables chosen for the study. The indication therefore is that age (p<0.050), education (p<0.0030), and marriage (p<0.036), have more potentials to improve farmers’ perception. Similarly, higher farmer incomes (from crops [p<0.017], off-farm [p<0.038] and overall [p<0.011] income) also have a likelihood to improve farmers’ perception regarding soil conservation, for improved adoption. Further indication is that farmers who are aware (p<0.015) of the soil practices introduced by extension are also those who participate in their use (p<0.041). Employing the binary logistic, probit and logit regression models, results suggest that the nature of adoption decision-making processes of smallholder farmers is complex (not straight), being influenced by multiple factors. While age (p<0.099), gender (p<0.031), total income (p<0.081) impacted positively significant on smallholder farmers’ adoption decision-making, marital status (p<0.025), sources of land (p<0.063), length of continuously farming on same piece of land (p<0.013), and level of crop production (p<0.002) impacted negatively. The indication therefore was that older farmers preferred their own practices to the recommended practices by extension, which is in line with literature. Also as expected, more females preferred their own practices to extension recommended, while more males preferred the recommended practices. Similarly, marriage, land ownership, farming continuously on a spot for a long period, as well as increase in the level of crop production, all had a propensity to influence farmers toward the adoption of extension recommended practices as against farmers’ practices. Further results indicate, that farmers’ education (p<0.032), household size (p<0.37), and income (off-farm [p<0.036] and total [p<0.004]), measures used to measure farmers’ livelihood standards in the study, were positively significant in association with adoption. The indication was that, adoption decision-making is potentially capable of improving education level of farmers; increase the size of household, thus providing easy family labour; and as well improve level of income for the farmer. Based on the foregoing, the suggestion therefore is that any technology intervention programme that will succeed must begin with a clear understanding and analysis of farmers’ adoption process. This is better achieved when the adoption process is seen as a four-stage process, where the farmer first forms a view about the innovation (perception stage), and then decides whether or not to use it (adoption stage), as well as how much of the innovation to adopt (level of adoption stage), and finally how much is this innovation going to affect my livelihood (impact of adoption stage). Also, due to the particular relevance of perception in the adoption decision-making process, technology disseminators (extension), researchers and policy makers alike must never conclude on the rejection of any technology, not until factors determining perception of individuals have been well studied. The notion here is that, even at the confirmation stage of the adoption process of an individual adopter, when a rejection is confirmed, for an example, analysing factors of the adopter’s perception at play at the particular time of the innovation in question, could go a long way to redirecting the course of the adoption process of the said individual.
- Full Text:
- Date Issued: 2016
- Authors: David, Ighodaro Ikponmwosa
- Date: 2016
- Subjects: Qamata Irrigation Scheme (South Africa) Irrigation -- South Africa -- Eastern Cape Farm management -- South Africa -- Decision making , Farms, Small -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/1740 , vital:27554
- Description: The goal of this study was to determine the nature and factors influencing smallholder farmers in their adoption decision-making regarding the use of soil conservation practices introduced by extension practitioners in South Africa, using the case of farming at Qamata Irrigation Scheme, Eastern Cape. Using a central argument (thesis statement), the study argued that an adequate understanding and definition of smallholder farmers’ adoption decision-making process is very crucial to solving the problem of soil erosion/ degradation problem amongst smallholder farmers. Adopting the case study research design, information from 70 crop farmers (in a farmer focus group interviews) form the basis of the study. Basic models of analysis were the multiple, probit and logit, as well as the binary logistic regression analyses. According to the empirical results, perception was found very relevant in adoption decision-making, interacting positively and significantly with eight of the seventeen adoption variables chosen for the study. The indication therefore is that age (p<0.050), education (p<0.0030), and marriage (p<0.036), have more potentials to improve farmers’ perception. Similarly, higher farmer incomes (from crops [p<0.017], off-farm [p<0.038] and overall [p<0.011] income) also have a likelihood to improve farmers’ perception regarding soil conservation, for improved adoption. Further indication is that farmers who are aware (p<0.015) of the soil practices introduced by extension are also those who participate in their use (p<0.041). Employing the binary logistic, probit and logit regression models, results suggest that the nature of adoption decision-making processes of smallholder farmers is complex (not straight), being influenced by multiple factors. While age (p<0.099), gender (p<0.031), total income (p<0.081) impacted positively significant on smallholder farmers’ adoption decision-making, marital status (p<0.025), sources of land (p<0.063), length of continuously farming on same piece of land (p<0.013), and level of crop production (p<0.002) impacted negatively. The indication therefore was that older farmers preferred their own practices to the recommended practices by extension, which is in line with literature. Also as expected, more females preferred their own practices to extension recommended, while more males preferred the recommended practices. Similarly, marriage, land ownership, farming continuously on a spot for a long period, as well as increase in the level of crop production, all had a propensity to influence farmers toward the adoption of extension recommended practices as against farmers’ practices. Further results indicate, that farmers’ education (p<0.032), household size (p<0.37), and income (off-farm [p<0.036] and total [p<0.004]), measures used to measure farmers’ livelihood standards in the study, were positively significant in association with adoption. The indication was that, adoption decision-making is potentially capable of improving education level of farmers; increase the size of household, thus providing easy family labour; and as well improve level of income for the farmer. Based on the foregoing, the suggestion therefore is that any technology intervention programme that will succeed must begin with a clear understanding and analysis of farmers’ adoption process. This is better achieved when the adoption process is seen as a four-stage process, where the farmer first forms a view about the innovation (perception stage), and then decides whether or not to use it (adoption stage), as well as how much of the innovation to adopt (level of adoption stage), and finally how much is this innovation going to affect my livelihood (impact of adoption stage). Also, due to the particular relevance of perception in the adoption decision-making process, technology disseminators (extension), researchers and policy makers alike must never conclude on the rejection of any technology, not until factors determining perception of individuals have been well studied. The notion here is that, even at the confirmation stage of the adoption process of an individual adopter, when a rejection is confirmed, for an example, analysing factors of the adopter’s perception at play at the particular time of the innovation in question, could go a long way to redirecting the course of the adoption process of the said individual.
- Full Text:
- Date Issued: 2016
A comparative study of the in vitro antidiabetic properties, cytotoxicity and mechanism of action of Albuca bracteata and Albuca setosa bulb extracts
- Authors: Odeyemi, Samuel Wale
- Date: 2015
- Subjects: Medicinal plants Herbs -- Therapeutic use Diabetics -- Alternative treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/3154 , vital:28327
- Description: The search for cheap, non toxic and readily available antidiabetic drugs has been a challenge for researchers and the pharmaceutical industries. Diabetes mellitus is a metabolic disease characterized by defects in the synthesis of insulin and/or insensitivity to the action of insulin at the target cells. The disease has been on the increase mostly in developing countries where large proportions of the population have little access to good medical care due to either accessibility or non availability of synthetic drugs. This has led to the use of medicinal plants to treat diabetes because it is safe, cheap and with few side effects. There is little scientific evidence on the dosages, active compounds, mechanisms of action and toxicity of these traditionally used plants. Two of the most frequently used plants; Albuca setosa and Albuca bracteata were investigated in this study. The qualitative analysis of different extractions of these plants revealed the presence of phenolics, alkaloids, tannins and saponins. The antioxidant properties of aqueous, acetone and methanollic extracts of Albuca setosa and Albuca bracteata were investigated using models such as Diphenyl-1-Picrylhydrazyl (DPPH), 2, 2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), Ferric ion reducing antioxidant potential (FRAP), Nitric Oxide and Hydrogen Peroxide (H2O2). Both plants revealed inhibitions against DPPH in a concentration - dependent manner with Albuca setosa (0.330 mg/ml) showing higher activity than Albuca bracteata (0.647 mg/ml) determined from the IC50. The aqueous extract of Albuca setosa showed a higher inhibition against DPPH radical compared to the Albuca bracteata aqueous extract at all concentrations investigated. The isolated saponins from Albuca bracteata had a higher DPPH scavenging activity than the crude methanolic extract of the plant in a concentration - dependent manner but are significantly different from each other at 0.4, 0.6 and 1.0 mg/ml only. The IC50 of the saponins was also observed to be higher than the crude extracts and standards.The Albuca setosa aqueous extract showed a higher percentage inhibition of ABTS radicals than Albuca bracteata at all the concentrations investigated. Overall, the Albuca setosa aqueous extract (0.0809 mg/ml) showed maximum activity against ABTS radicals. The iron reducing power was significantly higher (P < 0.05) in the methanolic extract of both plants compared to the aqueous counterpart. Overall, the Albuca bracteata aqueous extract (0.344 mg/ml) showed maximum activity as indicated by the IC50. The aqueous extracts of both plants also revealed percentage inhibitions in a concentration - dependent manner against NO2. The aqueous extract of Albuca bracteata bulb was more active against nitric oxide and hydrogen peroxide inhibition. In this study, the cytotoxicity of the extracts was evaluated at a high dose of 100 μg/ml on Chang liver cells and determined using MTT, crystal violet, glucose consumption, lactate production and lactate dehydrogenase release and FRAP. The aqueous extracts of both Albuca setosa and Albuca bracteata were non-toxic on Chang liver cells at the concentrations investigated. The MTT revealed that the aqueous extract of Albuca setosa bulb had the optimum cell viability of 108.09 percent while the acetonic extract of Albuca bracteata showed the least cell viability (37.72 percent) compared with the control. The crystal violet test also revealed the acetone extract of Albuca bracteata to have the least percentage of cell viability at 31.47 percent, while the aqueous extract of Albuca setosa showed the maximum cell viability at 112.5 percent. The aqueous extracts of both plants showed higher percentage cell density on the second day of incubation from the proliferation assay. All the tested samples were observed to consume more glucose than the blank except for the methanollic and acetone extracts of Albuca bracteata bulb. The aqueous and methanolic extracts of Albuca setosa bulbs produced the highest lactate with 120.2 μg/ml and 113.7 μg/ml respectively. The acetone extracts of both Albuca setosa and Albuca bracteata revealed toxicity with a higher lactate dehydrogenase release compared to the control.
- Full Text:
- Date Issued: 2015
- Authors: Odeyemi, Samuel Wale
- Date: 2015
- Subjects: Medicinal plants Herbs -- Therapeutic use Diabetics -- Alternative treatment
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10353/3154 , vital:28327
- Description: The search for cheap, non toxic and readily available antidiabetic drugs has been a challenge for researchers and the pharmaceutical industries. Diabetes mellitus is a metabolic disease characterized by defects in the synthesis of insulin and/or insensitivity to the action of insulin at the target cells. The disease has been on the increase mostly in developing countries where large proportions of the population have little access to good medical care due to either accessibility or non availability of synthetic drugs. This has led to the use of medicinal plants to treat diabetes because it is safe, cheap and with few side effects. There is little scientific evidence on the dosages, active compounds, mechanisms of action and toxicity of these traditionally used plants. Two of the most frequently used plants; Albuca setosa and Albuca bracteata were investigated in this study. The qualitative analysis of different extractions of these plants revealed the presence of phenolics, alkaloids, tannins and saponins. The antioxidant properties of aqueous, acetone and methanollic extracts of Albuca setosa and Albuca bracteata were investigated using models such as Diphenyl-1-Picrylhydrazyl (DPPH), 2, 2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), Ferric ion reducing antioxidant potential (FRAP), Nitric Oxide and Hydrogen Peroxide (H2O2). Both plants revealed inhibitions against DPPH in a concentration - dependent manner with Albuca setosa (0.330 mg/ml) showing higher activity than Albuca bracteata (0.647 mg/ml) determined from the IC50. The aqueous extract of Albuca setosa showed a higher inhibition against DPPH radical compared to the Albuca bracteata aqueous extract at all concentrations investigated. The isolated saponins from Albuca bracteata had a higher DPPH scavenging activity than the crude methanolic extract of the plant in a concentration - dependent manner but are significantly different from each other at 0.4, 0.6 and 1.0 mg/ml only. The IC50 of the saponins was also observed to be higher than the crude extracts and standards.The Albuca setosa aqueous extract showed a higher percentage inhibition of ABTS radicals than Albuca bracteata at all the concentrations investigated. Overall, the Albuca setosa aqueous extract (0.0809 mg/ml) showed maximum activity against ABTS radicals. The iron reducing power was significantly higher (P < 0.05) in the methanolic extract of both plants compared to the aqueous counterpart. Overall, the Albuca bracteata aqueous extract (0.344 mg/ml) showed maximum activity as indicated by the IC50. The aqueous extracts of both plants also revealed percentage inhibitions in a concentration - dependent manner against NO2. The aqueous extract of Albuca bracteata bulb was more active against nitric oxide and hydrogen peroxide inhibition. In this study, the cytotoxicity of the extracts was evaluated at a high dose of 100 μg/ml on Chang liver cells and determined using MTT, crystal violet, glucose consumption, lactate production and lactate dehydrogenase release and FRAP. The aqueous extracts of both Albuca setosa and Albuca bracteata were non-toxic on Chang liver cells at the concentrations investigated. The MTT revealed that the aqueous extract of Albuca setosa bulb had the optimum cell viability of 108.09 percent while the acetonic extract of Albuca bracteata showed the least cell viability (37.72 percent) compared with the control. The crystal violet test also revealed the acetone extract of Albuca bracteata to have the least percentage of cell viability at 31.47 percent, while the aqueous extract of Albuca setosa showed the maximum cell viability at 112.5 percent. The aqueous extracts of both plants showed higher percentage cell density on the second day of incubation from the proliferation assay. All the tested samples were observed to consume more glucose than the blank except for the methanollic and acetone extracts of Albuca bracteata bulb. The aqueous and methanolic extracts of Albuca setosa bulbs produced the highest lactate with 120.2 μg/ml and 113.7 μg/ml respectively. The acetone extracts of both Albuca setosa and Albuca bracteata revealed toxicity with a higher lactate dehydrogenase release compared to the control.
- Full Text:
- Date Issued: 2015