降解胆固醇的假单胞菌DGC-2的发酵培养基和培养条件

从动物粪便样品中分离出一株胆固醇氧化酶活力较高的DGC-2菌株,经鉴定为假单胞菌.利用单因子实验和正交试验对DGC-2菌株产胆固醇氧化酶摇瓶发酵的培养基及培养条件进行优化.其产酶的最适培养基为:蔗糖5 g/L,酵母粉3 g/L,牛肉膏1 g/L,吐温-80 1 g/L,胆固醇1 g/L,NH4NO31 g/L,KH2PO40.25 g/L,MgSO4.7H2O 0.25 g/L,FeSO40.001 g/L;最适培养条件为:初始pH6.5,接种量8.0%(v/v),32℃培养50h.在最适培养基及最适培养条件下,胆固醇氧化酶的活力可达到712 U/L.

Medium and Conditions of Culture of Pseudomonas sp.(DGC-2) Degrading Cholesterol

The bacteria strain(DGC-2) with high level of COD was isolated from animal intestines and identified as pseudomonas sp.The shake flask fermentation condition and medium of strain(DGC-2) producing cholesterol oxidase was optimized by single factor and orthogonal experiment.The optimum medium of culture with the highest enzyme activity included the following(g/L): sucrose 5.0,yeast extract 3.0,beaf extract 1.0,Triton-80 1.0,cholesterol 1.0,NH4NO3 1.0,KH2PO4 0.25,MgSO4·7H2O 0.25,FeSO4 0.001.The optimum of conditions of culture included the following: initial pH was 6.5,the inoculums volume was 8%(v/v),temperature was 32 ℃ for 50 h.Under the optimized cultivation conditions,the specific activity can reach 712 U/L.The productions of enzyme were markedly increased after optimization,which in turn facilitated the degradation of cholesterol.It is of benefit to the application research.