ONIBOKUN, ADEOLA ELIZABETH and Covenant University, Theses (2015) CHITINASE PRODUCTION BY CHITINOLYTIC BACTERIA FROM CATFISH (Clarias gariepinus). Masters thesis, COVENANT UNIVERSITY.
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Abstract
Chitinases are hydrolytic enzymes that breaksdown the glycosidic bonds in chitin. Chitin is a component of the cell walls of fungi and exoskeletal elements of some animals (including worms and arthropods), therefore chitinases are generally found in organisms that either needs to reshape their own chitin or dissolve and digest the chitin of fungi or animals. The importance of chitinase in industries cannot be overemphasized as it has been applied in agriculture; as a biopesticide for control of plant fungi infections, in medicine; as indicators of fungi infection, and in waste management; for biodegradation of fish waste. The African catfish (Clarias gariepinus) which plays host to these chitinolytic bacteria is very readily available and easy to cultivate thus providing a cheap means for the production of chitinase in commercial quantity. Bacteria populations Isolated from catfish were screened on colloidal-chitin agar medium. Chitinase production was determined by zones of hydrolysis produced after 96h of incubation at 37oC. The activity of Chitinase was determined by measuring the amount of reducing sugar released using Dinitroslicylic method. Partial purification of chitinase was carried out by Ammonium Sulphate precipitation. The optimum conditions for the chitinase activity were determined using a number of parameters such as temperature, pH, effect of substrate concentration and the time of heating over 30min. Optimum conditions were therefore ascertained at a temperature of 500C and a substrate concentration of 0.15g for chitinase produced by bacteria spp (isolate code 17 and 36) while pH 5.5 was obtained for isolate code 36 and pH 6.0 for isolate code 17. The Michaelis – Mentens constant (Km) which is also known as the dissociation constant is the substrate concentration at half maximum velocity. Calculated from the Lineweaver-Burk plot, the apparent Km values for the hydrolysis of chitin by chitinolytic bacterial isolate code 36 and isolate code 17 were approximately 0.09mg/ml and 0.007mg/ml respectively. Isolation of DNA and PCR amplification was carried out on the chitinolytic bacteria used for the study and one of the bacteria was identified as a member of the genus Bacillus. This study established that species of Bacillus inhabiting the gut and skin of the African catfish can be used to produce chitinase in appreciable quantity. The study has diversified the use of catfish for enzyme production rather than for consumption only. The catfish gut which constitutes a large portion of the fish waste will also serve as a cheap source for chitinase production.
| Item Type: | Thesis (Masters) |
|---|---|
| Subjects: | Q Science > Q Science (General) Q Science > QH Natural history > QH301 Biology |
| Divisions: | Faculty of Medicine, Health and Life Sciences > School of Biological Sciences |
| Depositing User: | Mrs Hannah Akinwumi |
| Date Deposited: | 12 Jun 2020 09:44 |
| Last Modified: | 12 Jun 2020 09:44 |
| URI: | http://eprints.covenantuniversity.edu.ng/id/eprint/13383 |
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