产几丁质酶烟草内生细菌的筛选及产酶条件研究

Isolation and Fermentation Conditions of Endophytic Bacterium Producing Chitinase in Tobacco

从健康烟草叶片中筛选出一株产几丁质酶活性较高的内生细菌FEC-1,经16 SrDNA基因序列和菌株生理生化特征分析,确定该菌株为环状芽孢杆菌。对FEC-1菌株产酶发酵条件研究表明,该几丁质酶是诱导酶,最佳氮、碳源是酵母膏和2 g/L单糖或二糖,多糖效果相对较差,最适初始pH为9.0左右,最适温度为30℃左右。在优化条件下,摇瓶培养60 h时产酶达123.16 U/mL。

The endophytic bacterium FEC-1 producing the chitinase has been isolated from the healthy tobacco leaf, and identified as Bacillus circulans according to its morphological and physiochemical and 16 SrDNA gene sequence analysis. Various fermentation conditions of its chitinase production were investigated. The results showed that the chitinase was an inducing enzyme and could be induced by the reagents such as colloid chitin, powder chitin and chitosan. The optimum fermentation conditions were found to be. yeast extract, 2 g/L saccharide or disaccharide, initial medium pH9.0 and culture temperature 30℃. Under the specified culture conditions, the highest chitinase activity was obtained to be 123.16 U/mL in 60 h at 220 r/min.