酒曲中高蛋白酶产生菌筛选及酶学性质研究

利用脱脂牛奶平板法从宋河酒曲中分离得到6株有明显水解圈的蛋白酶产生菌,其中水解圈直径与菌落直径之比最大为8.84,经鉴定为芽孢杆菌。以此菌种通过发酵培养提取出粗酶液,然后对该蛋白酶的酶学性质进行研究。试验表明,该蛋白酶的最适酶活力温度为40℃,在40℃～50℃热稳定性较好;该蛋白酶最适pH值为11.0,在pH值为9.0～11.0稳定性较好,在pH6.0条件下酶活力很快丧失;金属离子Fe2+对该蛋白酶有激活作用,Cu2+、Zn2+和Pb+有抑制作用,Mg2+、Ca2+和Li+对该蛋白酶酶活性影响不大。

Screening of protease-producing strains from Qu and research on enzymatic properties

Six strains,which had obvious hydrolysis circles on defatted milk plated,were isolated from Songhe liquor Qu.And the strains,which had the maximum ratio of the diameter of colony and the diameter of the hydrolysis circle of and the maximum ratio reached 5.84,was named M4.M4 was identified as Bacillus spp.The study of the properties of protease produced showed that the optimum temperature was 40℃,and the enzyme had good thermal stability at 40℃～50℃.And the optimal pH of the protease is 11.0 and its stability is good in the pH range of 9.0～11.0;while when pH6.0,the protease activity will be lost very quickly.Fe2＋ ions can activate the protease,while ions of Cu2＋、Zn2＋ and Pb＋ inhibit the protease,ions of Mg2＋、Ca2＋ and Li＋ have little effect on the protease activity.