氯化锂-离子束复合诱变核酸酶P1高产菌株研究

Screening of strains producing nuclease P1 by compound mutation of LiCl and ion beam

为满足日益增长的核酸酶P1工业生产需求,以桔青霉为研究对象,研究了氯化锂、离子束2种方式复合诱变对桔青霉的影响,根据后代的致死率和正突变率确定最佳诱变条件为:氯化锂的最佳诱变浓度为1.4%,离子束的最佳诱变注量为10 keV、1.5×1015 ions/cm2。经氯化锂-离子束复合诱变筛选到高产突变株L-I-4-f,该菌株摇瓶酶活达1166 U/mL,较出发菌株d-3-12提高45.8%,经多次传代分离该突变株遗传稳定性较好。

For meeting the needs of high-yield industrial production strains of nuclease P1, use LiCI and ion beam mutation ways to do research on Penicillium citrinum. The mutation conditions were optimized by fatality rate and positive mutation rate. The optimum mutation concentration of LiCI is 1.4%, the optimal fluence of ion beam is 10 keV, 1.5×10^15 ions/cm2. Then the two ways were combined to do compound mutation, one high-yield mutant L-I-4-f was obtained. The enzyme activity of the strain is 1166 U/mL, which is nearly 45.8% highter than the original strain d-3-12. Several passages and separation experiments show that the heredity of mutants was stable.