产凝乳酶米黑毛霉的诱变育种研究

Study on mutation breeding of Mucor miehei producing milk- clotting enzyme

摘要: 以产凝乳酶的米黑毛霉为出发菌株,通过紫外线照射、紫外复合氯化锂处理,以筛选产凝乳酶活力较高的菌株。确定的紫外线最佳照射时间为90 s,经多次诱变,筛选得到了突变株UV-13,其凝乳酶活力为2448.98 SU/m L,比出发菌株提高了42.85%;复合诱变的最佳条件为90 s紫外照射复合1.5%氯化锂,在多次诱变的基础上,筛选得到了突变株UV-Li Cl-6,其凝乳酶活力为2703.58 SU/m L,比出发菌株提高了57.70%。传代实验表明,两株突变菌都具有良好的遗传稳定性。

Abstract: In order to breed high activity milk- clotting enzyme from strain,Mucor miehei was used as the origin strain and mutagenized by Ultraviolet and Ultraviolet combining lithium chloride.The optimal condition of Ultraviolet was 90 s. After screening repeatedly,a mutant strain UV- 13 was screened. The milk- clotting activity of UV- 13 reached 2448.98 SU / m L and was 42.85% higher than that of the parent strain. The best condition of compound mutation were that the time of Ultraviolet was 90 s,the concentration of lithium chloride was 1.5%.On the basis of multiple mutation,a mutant strain UV- Li Cl- 6 was screened. The milk- clotting activity of UV- Li Cl- 6 reached2703.58 SU / m L and was 57.70% higher than that of the parent strain.Results of the pass- generation test indicated that two strains had good genetic stability.