Characterization Of Chitinase From The African Catfish, Clarias Gariepinus (BURCHELL, 1822)
Chitinases are hydrolytic enzymes that break down the glycosidic bonds in chitin. The role of Chitinases in the treatment and prevention of various diseases have been reported. They have been implicated in the human health care for the treatment of fungal infections, in Asthma and in the control of mosquito which causes the deadly malaria disease accounting for about 70% of infant mortality in Africa. Chitinase was obtained from chitinolytic bacteria inhabiting the skin and gut of the African Catfish (Clarias gariepinus). Bacterial population Isolated from catfish was screened on colloidal-chitin agar medium. The ability to produce Chitinase was determined by zones of hydrolysis produced after 96h of incubation at 37oC. Isolation of chitinase was carried out with colloidal chitin as substrate in sodium phosphate buffer. 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 carried out identified the bacteria 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 for Chitinase production in appreciable quantity.
Keywords: Chitinases, Clarias gariepinus, Chitin, PCR, Bacillus sp