三重诱变选育腈水合酶高产菌株

[目的]获取高产的腈水合酶产生菌。[方法]以腈水合酶产生菌诺卡氏菌（Nocardia sp.）为出发菌株,采用加热、紫外线（UV）照射、硫酸二乙酯（DES）处理三重复合诱变,研究不同诱变剂量对致死率和正突变率的影响,选育腈水合酶高产菌株,并研究底物类似物乙腈对该菌株腈水合酶活性的影响。[结果]从中筛选出1株稳定、高活力的腈水合酶生产菌,所产腈水合酶最高活性提高到1 238万U。在一定浓度下,随着底物类似物乙腈浓度的增大,菌株正突变率和所产腈水合酶最高酶活增大,但超过一定浓度后正突变率和最高酶活反而下降。[结论]获得了1株稳定的腈水合酶高产菌株,所产腈水合酶活性高达1 238万U。底物类似物乙腈对该菌株的正突变率和所产腈水合酶最高酶活性有一定的影响。

Breeding of the Strain with the High-yield of Nitrile Hydratase by Means of the Method of Triple Mutation

[Objective] The strain with the high-yield of nitrile hydratase(NHase) was bred by means of the method of triple mutation.[Method] The Nocardia sp.producing NHase,being taken as the starting strain,was mutated with heating,UV irradiation and 2-sulfuric acid ethyl ester(DES) and the mutant with high-yield of NHase was screened after the effect of different treating dosages on its mortality and positive mutation rate was researched.The influence of the substrate analogue acetonitrile on the activity of nitrile hydrated enzyme of the stain was tested.[Results] A stable mutant with high active strain producing NHase was bred,which highest activity of NHase was as high as 1.238×108 U.Under the condition of certain concentration,the positive mutation rate of strain and the highest activity of it producing NHase were raised with the increment of the concentration of the substrate analogue acetonitrile,however,they would be reduced over the certain concentration.[Conclusion] A stable mutant with high active strain producing NHase was bred,which highest activity of NHase was as high as 1.238×108 U.The substrate analogue acetonitrile could affect the positive mutation rate of strain and the highest activity of it producing NHase.