高产胆固醇氧化酶菌株的诱变选育

目的]选育高产胆固醇氧化酶菌株。方法]从环链拟青霉、斜链拟青霉、中国拟青霉和蛹拟青霉中筛选出发菌株，对筛选出的酶活力高的突变株进行紫外诱变，选育出高产胆固醇氧化酶突变株，对其发酵条件进行优化并测定其酶活。结果]选择环链拟青霉为诱变选育的出发菌株，紫外诱变环链拟青霉获得了一株高产胆固醇氧化酶突变株CM3，确定了紫外诱变的最佳时间是80S。通过优化其发酵条件，得出CM3发酵产酶最优条件为30℃，pH值6．0，接种量为10％。其最高酶活力为1．3360U／ml，比出发菌株（0．3369U／m1）提高了296．6％。结论]通过紫外诱变能选育出有较高胆固醇氧化酶活力的菌株。

Mutation Breeding of High-Yield Strain of Cholesterol Oxidase

Objective] The aim was to breed the high-yield strain of cholesterol oxidase.Method] The starting strain was screened from Paecilomyces cateniannulatus,Paecilomyces cateniobliquus,Paecelomyces sinensi and Paecilomyces militaris.The screened mutant with high enzyme activity was mutated by ultraviolet to breed the mutant with high-yield cholesterol oxidase.Its fermentation condition was optimized and the enzyme activity was detected.Result] P.cateniannulatus was screened as the starting strain for mutation breeding and after it was mutated by ultraviolet,a mutant with high-yield cholesterol oxidase CM3 was obtained.The optimum time for ultraviolet mutation was 80 s.The optimum condition for fermentation and producing enzyme of CM3 was 30 ℃,pH 6.0 and the inoculation amount of 10%.Its highest enzyme activity was 1.336 0 U/ml,which was improved by 296.6% compared with the starting strain of 0.336 9 U/ml.Conclusion] Ultraviolet mutation could breed strains with higher cholesterol oxidase activity.