产几丁质酶海洋细菌的筛选及发酵条件的优化

Isolation and fermentation optimization of marine bacteria with chitinase activity

目的：筛选产几丁质酶活力的菌株，研究菌株产酶的最适发酵条件，并对酶解产物进行检测。方法：利用平板透明圈法初筛产几丁质酶的菌株，再利用DNS法复筛菌株，将初酶液和胶体几丁质在37℃水浴反应，经离心，透析，浓缩，再通过薄层色谱（TLC）和高效液相色谱（HPLC）对酶解产物进行检测。结果：SG-05海洋细菌能降解几丁质为3～5聚合度的几丁寡糖。其发酵液最大酶活可达0．85U·mL^-1。结论：利用平板透明圈法和DNS法相结合，可以较为迅速准确筛选到产几丁质酶活力的菌株，利用薄层色谱和高效液相色谱法可准确对酶解产物进行定性分析，通过发酵条件的优化，产酶活力提高近2倍。

Objective： To screen the strains with high chitinase activity, and to optimize the fermentation and detect their enzymolysis products. Methods： The strains were screened by the method of transparent zones using a selective medium. After being centrifugated, dialyzed and condensed, the products were detected by thin layer chromatography （TLC） and high performance liquid chromatography （HPLC）. Results： Chitin was degraded to chitooligosaecharide with 3 -5 polymerization degree by the chitinase produced from strain SG05. The maximum enzymatic activity （0.85 U·mL^-1 ） was obtained. Conclusion ： The method of transparent zones combined with the method of DNS is able to rapidly screen strains with high ehitinase activity. TLC and HPLC methods are suitable for the accurate and quantitative analysis for the products. Through the optimization of fermentation, the enzymatic activity produced by strain SG05 is increased by nearly 2 times.