Identification Of A Chitosanolytic Enzyme From Beta Proteobacterium C-28

A group of chitin/chitosan-degrading bacteria were isolated from soil samples of Zhejiang province, and they were classified initially based on 16S rRNA sequences analysis. The strain C-28 was mainly studied and identified as Bacteria, Proteobacteria, Beta proteobacteria, Burkholderiales, Burkholderiaceae. The strain secrets chitosanase into surrounding medium, in the presence of chitosan. By the orthogonal test, the optimal condition for the production of chitosanase was determined, and the chitosanase activity reached 3.81 U/ml when strain C-28 was incubated under the optimal condition for 48 h. The induced-chitosanase was purified from the culture supernatant of strain C-28 by ammonium sulfate precipitation and Sephadex G-200. Its molecular mass was estimated to be about 34.9 kD by SDS-PAGE. The optimum pH and temperature for hydrolysis of the chitosanase were about pH 7.0 and 46 , respectively. The enzyme activity was relatively stable below 45 癈 with a range of pH 5-8. Metal ions of Mg2+, Mn2+, Na+ and K+ significantly stimulate the chitosanase activity, while Cu2+, Fe2+, Fe3+and Co2+ inhibit it. The hydrolysis product assayed by TLC suggested that the chitosanase catalyzed an endo-type cleavage reaction. Moreover, the chitinase and chitosanase from CJ-5 were also purified and analysed.