Screening Of Chitinase-producing Bacteria Strains, Fermentation And Some Properties Of Chitinase

As an original chitinase-producing strain s and strain d, screened from soil, mixed fermentation get an high chitinase-producing. The optimal compositions of the medium for the strain producing chitinase are as follows(%,w/v): CO(NH2)2 1.0,K2HPO4 0.07, KH2PO4 0.03,MgSO4·7H2O 0.05,yeast extract 0.5 the chitin 1.0 (pH 5.5).The optimal cultivation conditions for the strain producing chitinase were 500mL flask containing 100mL medium,2%(v/v)amount of inoculation,32℃incubating temperature and shaking cultivation at 130 rpm for 72 hours. The most activity of chitinase of fermentation broth is 1.19U/ml.The chitinase is extracted by ammonium sulfate precipitation(40～80% saturation), purified by chitin affinity chromatography and gel filtration (Sephacryl S-100 column). SDS-PAGE shows a single band for the purified chitinase and the molecular weight is estimated to be 45 kDa. The optimal temperature and pH for hydrolysis of the chitosanase are 60℃and 5.5,.It had relatively broad pH adaptability and demonstrated to be relatively heat resistant. The enzyme activity was significantly inhibited by Cu2+, Zn2+ and slightly activated by Fe2+,Mn2+at ion concentration being 5 mmoL/L. The enzyme shows activity for hydrolysis of chitin , chitosan and cm- chitin . Acorrding to the study,the chitinase showed a good stability.