Isolation and Characterization of Chitinolytic Bacteria for Chitinase Production from the African Catfish, Clarias gariepinus (Burchell, 1822)

Abstract

Chitinases are hydrolytic enzymes that break down 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. African catfish (Clarias gariepinus) which plays host to bacteria is very readily available and easy to cultivate thus providing a cheap means of obtaining chitinolytic bacteria for the production of chitinase in commercial quantity. Bacteria populations isolated from the skin and gut of catfish were screened on colloidal-chitin agar medium. Chitinase production was determined by zones of hydrolysis produced after 96 h of incubation at 37EC. The result of this investigation revealed thirty-six pure bacterial isolates from the skin and gut of catfish. Gram staining test revealed, twenty five Gram positive bacteria while eleven were Gram negative. After four days of incubation, twenty-six bacteria isolates obtained from the gut and skin of catfish were selected as chitinase producing bacteria based on the clear zones of hydrolysis produced. The bacterial isolates obtained will be very useful for the production of chitinase which can be employed for the biocontrol of fungal pathogens and harmful insects. This study presents a first time report of Chitinase producing Bacillus cereus from the gut of catfish (Clarias gariepinus).