一株地衣芽孢杆菌碱性蛋白酶的研究Ⅱ

STUDIES ON THE ALKALINE PROTEASE SECRETING FROM A BACILLUS LICHENIFORMIS Ⅱ.

曾分离到一株产碱性蛋白酶的地衣芽孢杆菌 0 1 1 ,命名为地衣芽孢杆菌砀山亚种。酶的最适作用条件 :pH9 0 ,6 0℃。对该菌株进行连续 4次不同的物理、化学方法的诱变处理。诱变剂为紫外线、亚硝酸、和低能N+离子 ,其处理方式包括单独或复合处理两种。最后获得一株高产碱性蛋白酶的变异株 (C3 0 3)菌株产酶活力从 72 5u/mL提高到 1 2 4 2 5u/mL。该突变株的最适产酶条件为起始pH8 0～ 9 0 ,培养温度 3 2℃～ 3 7℃ ,振荡培养时间 44～ 48h。

Strain 011 isolated from salt-soda soil in the north of Anhui province was identified,and its alkaline protease was studied.Results indicated it possesses characters common to Bacillus licheniformis,but differs from known typical strain of Bacillus licheniformis in sporange shape?spore location and tolerant degree to salt and alkalinity.The strain may grow in medium with13%NaCl and the value of pH12.Strain 011,therefore,was identified as a subspecies of B.licheniformis and designated as Bacillus licheniformis subsp.dangshanensis.Growing in fermentative medium,the strain can produce high yield alkaline protease (725u/mL),whose optimum conditions are pH 9.0 and 60℃.The enzyme is stable in the range of pH form 6-11.