- Title
- Chicken feather delipidation by lipolytic bacteria isolated from an aquatic environment
- Creator
- Shiri, Tariro https://orcid.org/0000-0002-0290-9854
- Subject
- Keratin
- Date
- 2021-02
- Type
- Master's theses
- Type
- text
- Identifier
- http://hdl.handle.net/10353/21479
- Identifier
- vital:48693
- Description
- Keratinous biomass contributes a significant proportion of agro-based wastes in the ecosystem with minimal potentials for valuable product recovery. The generation of huge quantities of chicken feather from poultry processing farms prompts the valorization attempt via diverse avenues. Chicken feathers are a rich source of valuable keratin, yet the overall value chain is rudimentary based on unsustainable recovery techniques involving corrosive chemicals and high energy input processes. Although attempts have been made to extract keratin using microbial techniques successfully, the pre-treatment stage remains dominated by chemical use. Chicken feathers are composed of approximately 91percent keratin, 1percent lipids, and 8percent water. Therefore, lipid removal is a critical step in the valorization process as they contribute to access hindrance of the keratinases and other sulfitolytic systems to keratin. Consequently, the study undertook to explore the environment for lipolytic bacteria capable of degrading chicken feathers' lipid components. Sediment samples were collected for bacteria isolation. The bacteria were evaluated for lipolytic activity, and the potent isolates were identified based on 16S rRNA gene sequencing. The fermentation conditions for the production of extracellular lipases were optimized, and the produced lipases were characterized. Lastly, chicken feather lipids were hydrolysed with lipolytic bacteria. Out of twenty bacteria isolated from the sediment samples, six isolates coded as ACT003, ACT004, ACT010, ACT013, ACT016, and ACT019 showed lipolytic activity on solid media with a respective diameter of 12 mm, 66 mm, 29 mm, 11 mm, 12 mm, and 10 mm. Based on 16S rRNA gene sequencing and phylogenetic analysis, the isolates coded as ACT004 and ACT010 were identified as Bacillus sp. TTs1 and Bacillus sp. TTs2; and the nucleotide sequences were submitted to GenBank (NCBI) with the accession numbers MW556206 and MW556207, respectively. Bacillus sp. TTs1 showed the maximum lipase production of 641.25 U/mL at 72 h, under optimized conditions that included initial pH (5), inoculum size (2percent, v/v), incubation temperature (45 oC), agitation speed (140 rpm), CaCl2 (0.01percent, w/v), yeast extract (1percent, w/v), and tween-80 (10percent, v/v). Similarly, the lipase production by Bacillus sp. TTs2 peaked at 96 h with enzyme activity of 618.8 U/mL in improved fermentation conditions consisting of initial pH (5), inoculum size (2-8percent, v/v), incubation temperature (25 oC), agitation speed (180 rpm), CaCl2 (0.01percent, w/v), yeast extract and peptone (1percent, w/v), and tween-80 (10percent, v/v). The evaluation of chicken feather concentrations on free fatty acid liberation showed that 6-8percent (w/v) chicken feather was adequate with free fatty acids contents of 0.58percent and 0.86percent for Bacillus sp. TTs1 and Bacillus sp. TTs2, respectively. Both isolates' lipases showed remarkable catalytic efficiency at pH and temperature of 7 and 40oC, respectively. The comparative analysis of residual lipids between pre-and post-fermentation indicated a 39.9 ± 7.8percent and 51.2 ± 20.2percent hydrolysis efficiency for Bacillus sp. TTs1 and Bacillus sp. TTs2, respectively. This study's findings indicated the lipolytic potentials of Bacillus spp. and suggest the possibility of a full bio-based approach for chicken feather lipid removal in the valorization of chicken feathers.
- Description
- Thesis (MSc) -- Faculty of Science and Agriculture, 2021
- Format
- computer
- Format
- online resource
- Format
- application/pdf
- Format
- 1 online resource (113 leaves)
- Format
- Publisher
- University of Fort Hare
- Publisher
- Faculty of Science and Agriculture
- Language
- English
- Rights
- University of Fort Hare
- Rights
- All Rights Reserved
- Rights
- Open Access
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UFH Department of Biochemistry & Microbiology
| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details | SOURCE1 | Tariro Shiri _ MSc Dissertation.pdf | 2 MB | Adobe Acrobat PDF | View Details |