Effect of chitin sources on production of chitinase and chitosanase byStreptomyces griseus HUT 6037

The advantage of usingStreptomyces griseus HUT 6037 in the production of chitinase or chitosanase is that the organism is capable of hydrolyzing amorphous or crystal-line chitin and chitosan according to the type of the substrate used. We investigated the effects of the enzyme induction time and chitin sources, CM-chitosan and deacetylated chitosan (degree of deacetylation 75–99%), on production of chitosanase. We found that this strain accumulated chitosanase when cells were grown in the culture medium containing chitosanaceous substrates instead of chitinaceous substrates. The highest chitosanase activity was obtained at 4 days of cultivation with 99% deacetylated chitosan. Soluble chitosan (53% deacetylated chitosan) was found to induce chitinase as well as chitosanase. The specific activities of chitinase and chitosanase were 0.91 and 1.33 U/mg protein at 3 and 5 days, respectively. From the study of the enzymatic digestibility of various degrees of deacetylated chitosan, it was found that (GlcN)₃, (GlcN)₄ and (GlcN)₅ were produced during the enzymatic hydrolysis reaction. The results of this study suggested that the sugar composition of (GlcN)₃ was homogeneous and those of (GlcN)₄ and (GlcN)₅ were heterogeneous.