可降解蓖麻饼粕的蛋白酶产生菌筛选及产酶条件优化

利用酪素平板透明圈法初筛和测蛋白酶活力复筛,从分离自蓖麻饼粕和实验室保存的菌株中筛选出1株高产蛋白酶菌株P3-2,对其产酶条件进行了研究。结果表明,最适碳源为麦芽糖,最适氮源为蓖麻饼粕,Na+对产酶具有促进作用,培养基初始p H值为7.5时出现产酶高峰,最适接种量为4%,培养到36 h和84 h时有两个产酶高峰。经正交试验优化,得到较佳产酶培养基组成:2.0%麦芽糖、1.0%蓖麻饼粕及1.0%Na Cl。

Screening of Protease-Producing Bacterium for Degrading Castor Bean Meal and Optimization of Its Fermentation Conditions

A strain named P3-2 with the ability to produce protease was isolated from castor bean meal and laboratory preservation by the casein plate culture method and enzyme activity detection. The optimal fermentation conditions were investigated. The optimum carbon and nitrate sources were maltose and castor bean meal. Meanwhile, the yield of protease was increased by adding Na⁺ and one peak of the protease yield was obtained when the initial pH value of medium was 7.5. Moreover, the optimum amount of inoculum was 4% and there were two peaks of the protease yield when culture time was 36 h and 84 h. Through the orthogonal experiment, the optimum compositions of medium were as follows:2.0% maltose, 1.0% castor bean meal, and 1.0% NaCl.