碱性淀粉酶菌株的紫外线和He-Ne激光复合诱变的研究

Study on the Breeding of Alkaline Amylase Producing Strain by Ultraviolet and He-Ne Laser Compound Mutation

以嗜碱芽胞杆菌（alkaliphilic bacillus）BC—A36为出发菌株，通过紫外线，N-甲基-N’-硝基一亚硝基胍（亚硝基胍NTG）和激光复合诱变处理，选育出一株高产碱性淀粉酶的突变株JG57，在摇瓶发酵培养基上35～37℃培养45h，测得酶活力稳定在867u／mL左右，为出发菌株酶活力的2．1倍。该突变株产酶温度在25～43℃，最适温度37℃，产酶pH值7～12，最适pH值9。该酶较稳定的pH值适宜范围为9．5～10。传代实验证明，该突变株遗传性能稳定。说明激光辐照是碱性淀粉酶菌株有效的选育方法。该突变株产生的碱性淀粉酶可适用于淀粉的液化、洗涤及纺织工业等。

By compound mutation treatment with ultraviolet （UV）, nitrosoguanidine （NTG） and laser irradiation to the initial strain （alkaliphilic bacillus ）BC-A36, the mutant JG-57 with high alkaline amylase activity was obtained. In the shaking flask culture with fermentation medium at 35-37℃ for 45 hours its enzyme activity reached 867 u/ mL, which was 2. 1 times greater than that of the initial strain. Enzyme synthesis occurred at temperatures between 25-43℃ with an optimum of 37 ℃. There was a variation in amylase synthesis within the pH range 7-12 with an optimum pH of 9. The alkaline amylase produced by lhe mutant JG-57 had strong adaptability to high pH of 9.5-10. The results showed that the mutant was genetically stable, h proves that laser irradiation is an effective method for breeding of alkaline amylase producing strain. The JG-57 alkaline amylase is suitable in liquefaction of starch, detergent and textile industries and other industrial applications.