紫外-激光复合诱变选育天冬氨酸转氨酶高产菌株

Screening of High Aspartate Aminotransferase Producing Strains by UV and He-Ne Laser Irradiation

对天冬氨酸转氨酶产生菌大肠杆菌XJ-1原生质体进行紫外-激光复合诱变筛选,结果表明,复合诱变对该菌的原生质体有明显的致死作用。以致死率和正突变率为指标,确定了紫外和He-Ne激光照射的最佳时间分别为45 s和40min。在此条件下对大肠杆菌原生质体进行紫外-激光复合诱变,得到3株高产菌株,分别命名为XJ-1-45、XJ-1-86和XJ-1-99,酶活较出发菌株XJ-1分别提高了12.82%、17.37%和26.27%。传代培养表明突变株生产性能稳定。

Protoplast of E.coli XJ-1 producing aspartate aminotransferase was irradiated by UV and He-Ne laser compound mutagenesis.The result showed that compound mutagenesis had obvious lethal effect on E.coli XJ-1 protoplast.With the death rate and positive mutation as criteria,the optimum time for UV and He-Ne laser irradiation was 45s and 40 min respectively.Three high-yielding strains named XJ-1-45,XJ-1-86 and XJ-1-99 were obtained by 45s UV and 40min He-Ne laser compound mutagenesis,and activities of aspartate aminotransferase were increased by 12.82%、17.37% and 26.23% than that of the XJ-1 strain respectively.The mutants have good hereditary stability after sub-culturing several times.