Screening And Identification And Studies Of Enzyme Characteristics Of The Chitindegrading Strains

Chitinase (EC3.2.1.14) can decompound chitin, which are the second largest natural resources reserves in the world and its composing products are very useful in industry, agricultural, pharmaceutical and environmental fields. chitinase has great social benefit and economical benefit in several aspects. the study of chitinase which were isolated from the edaphon has important significance in the exploiture of the new chitinase resources.Several bacterium and fugus with chitin decompounded activity were screened from the soil on chitin agar plate in this study by observation of clearing zones. one strain bacterium and fugus with higher decompounding activity are screened from these strains by clearing zones and Schales method, their activity reached 1.228U and 0.192U,which are named as JX-X-7 and JX-Z-7. Each of the two strains'growth curve were determined, the species were identified species and the condition of the ferment and the reaction to improve enzyme activity were optimized with single factor selecting method, and the chitinase was purified and their molecular weight were determined.Through primary work, strains which named as JX-X-7 and JX-Z-7 were identified as Staphylococcus Rosenbach, and Aspergillus respectively. From the growth curves, the exponential phase of the JX-X-7 was determined between 3h and 12h, and the exponential phase of the JX-Z-7 was between 24h and 30h. The optimum growth condition of the JX-X-7 was pH 8.0, 35℃for 6.5 days, its optimum reaction condition was pH7.0, 30℃for 2 min; the optimum growth condition of the JX-Z-7 was pH6.0, 35℃for 5 days, and its optimum reaction condition was pH6.5, 40℃for 2 min. The optimization improved the unite enzyme activity of JX-X-7 from 0.192U to 3U, nearly 15.6 times higher, and the unite enzyme activity of JX-Z-7 from 1.228U to 39.1875U, nearly 32 times higher.Saturation (NHB4B)B2BSOB4B deposition, and the Sephadex G-100 column gel filtration were adopted to purify chitinase. 70% was determined as optimal saturation for JX-X-7, and 90% for JX-Z-7 for deposition and collection once-only, the treated samples were desalted by dialyzing, and were condensed foe loading. Through Sephadex G-100 column gel filtration, single band was got on SDS-PAGE,the purification times of the chitinase produced by the JX-X-7 reached 1.351, the recovery rate was 29.71%, and the molecular weight was finally determined as 25.0kDa. The purification times of the chitinase produced by the JX-Z-7 reached 6.484, the recovery rate was 42.97% and the molecular weight was finally determined as 28.0kDa.