产普鲁兰酶菌株ZXYG5的分离鉴定及其普鲁兰酶活性

Isolation,identification and enzyme activity of pullulanase-producing strain ZXYG5

通过以支链淀粉为唯一碳源的分离培养基和以普鲁兰糖为唯一碳源的鉴别培养基复筛,从烟草甲(Lasioderma serricorne)肠道中分离得到一株产普鲁兰酶菌株,编号为ZXYG5.该菌株在以普鲁兰糖为碳源的产酶培养基35℃、160 r·min^(-1)条件下发酵42 h时,普鲁兰酶活性达到最大值4.2 U·m L^(-1).通过光学显微镜和扫描电子显微镜的形态观察、生理生化特性和16S r DNA保守序列分析,将菌株ZXYG5初步鉴定为泛菌属Pantoea sp.,命名为Pantoea sp.ZXYG5.该菌株具有较高的初始产普鲁兰酶活性,可作为常规诱变育种和全基因组育种的良好备选菌株.

After being inoculated with amylopectin and pullulan as sole carbon source successively,strain ZXYG5 with potential of pullulanase production was isolated from gut of tobacco beetle（ Lasioderma serricorne）. The optimal fermentation condition was 35℃,160 r·min^-1 and 42 h with maximum pullulan yield of 4. 2 U·m L^-1. Subsequent standard morphological observation,physiological and biochemical property analysis,and 16 S r DNA sequencing test indicated strain ZXYG5 was Pantoea sp.,and was named Pantoea sp. ZXYG5. Strain ZXYG5 with satisfactory initial pullulanase activity can be used as a good alternative to conventional mutation and genome breeding.