Purification of chitinase 42 from Trichoderma atroviride PTCC5220

Chitinases are widely distributed in nature and play important roles in degradation of chitin. Chitin, a linear polymer of N-acetylglucosamine residues, has been the most abundant polymer in nature after cellulose. It plays a major role in fungal cell walls. Chitinase enzymes degrade the chitin polymer into its component residues by breaking the β-1,4 glycosidic bonds. As a producer of a variety of chitinase enzymes, the filamentous fungus, Trichoderma sp., has become an important means of biological control for fungal diseases. The aim of this study was to identify a Trichoderma sp. isolate with over production of chitinase. Trichoderma atroviride PTCC5220 was selected as over producer of chitinase enzyme among 31 different isolates of Trichoderma sp. Also chitinase 42 kDa (Chit42) was purified from supernatants of T. atroviride grown in medium supplemented with colloidal chitin as the sole carbon source. Enzyme purification was achived in two steps ion exchange chromatography using CM-Sepharose and DEAESepharose. Elution of the column was carried out with 1 M NaCl gradient. The purity of chit42 was investigated by SDS-PAGE. The results showed one band about 42 kDa after the second step of chromatography. The purified protein showed chitinase activity in enzyme assay technique.