产凝乳酶解淀粉芽孢杆菌的诱变选育

Study on mutation breeding of Bacillus amyloliquefaciens producing milk- clotting enzyme

摘要: 为了获得高产凝乳酶菌株,以产凝乳酶解淀粉芽孢杆菌为出发菌株,采用紫外线和硫酸二乙酯进行诱变。诱变后筛选得了一个突变株L-6,凝乳活力为1419.7 SU/m L,比原始菌株提高了40.2%;水解活力降低了22.39%,凝乳活力与蛋白水解活力的比值为125.64,比出发菌株提高了81.32%。传代实验表明,该菌株具有良好的遗传稳定性。

Abstract: To obtain an industrial strain with high milk- clotting activity,Bacillus amyloliquefaciens producing milkclotting enzyme was mutagenized with ultraviolet and diethyl sulfate. On the basis of multiple mutation,mutant DES-6 was screened.The milk- clotting activity of L-6 reached 1419.7 SU / m L,which was 40.2% higher than that of the parent strain,while the proteolytic activity was reduced by 22.39%. The ratio of milk- clotting activity to proteolytic activity reached 125.64,which was 81.32% higher than that of the parent strain.The pass- generation test indicated that DES-6 had good genetic stability.