Study on Selection of Chitinase – Producing Bacillus Thuringiensis and Survey Their Chitinase Biosynthesis Affecting Factors

The study is conducted with the aim of finding Bacillus thuringiensis with the highest chitinase activity and optimal conditions for chitinase biosynthesis for the chitinase production in application for plant diseases control. From 25 soil samples collected from Tuy Loan, Hoa Vang district, Da Nang city, we have isolated 3 strains of Bacillus thuringiensis with chitinase activity (T1, T2 and T3). Among them, T3 strain has the highest chitinase activity. The result of identification by sequencing 16S rRNA shows that the T3 strain has 99.86% similarity to Bacillus thuringiensis SRG2. The highest chitinase activity of T3 strain is obtained after 48h culture in medium containing peptone and lactose as nitrogen and carbon source respectively, pH = 7, The different forms of chitin (chitosan, colloidal chitin, shrimp shells) supplemented to the culture medium do not significantly affect the ability of chitinase activity of T3 strain