高产蛋白酶菌株的分离鉴定及诱变

目的:从豆豉中分离出高产蛋白酶的菌株并进行紫外诱变,以提高菌株的产蛋白酶能力。方法:采用酪蛋白平板法,初步筛选出一些产蛋白酶菌株,通过比较发酵后蛋白酶活力,筛选出一株产蛋白酶活力最高的菌株,鉴定其菌种,对该菌株进行紫外诱变,并对诱变后的菌株进行筛选,最后得到一株产蛋白酶活力最高的菌株。结果:分离鉴定后得知菌株B为地衣芽孢杆菌,产蛋白酶活力为2360.80U/mL。最佳诱变时间为120s,菌落致死率为66.68%,得到的高产蛋白酶菌株为B-14,其蛋白酶活力为2922.90U/mL,诱变后菌株产蛋白酶活力提高了23.81%。结论:通过筛选、诱变成功选育出高产蛋白酶的菌株B-14。 

Isolating,identification and mutation of a high protease producing strain in Douchi

Objective:To improve the ability of protease producing, a high-yielding strain of protease from fermented Douchi was isolated, and the enzyme activity of this strain after ultraviolet mutagenesis was identified.Methods:Firstly, the protease producing strains were isolated from Douchi by casein plate method.By comparing the enzyme activity of proteases after fermentation, the strains which can produce most proteinase were selected.And then identified the strain breed, studied the enzymology and did mutagenize in order to elevate their ability about producing proteinase.Finally a high protease producing strain was obtained in Douchi.Results:According to the results of microscope testing and physiological and biochemical characteristics, the strain B isolated from Douchi belongs to the bacillus licheniformis, the activity of enzyme reached 2360.80U/mL.The best mutagenesis time of this strain was 120s, colonies mortality rate was 66.68%, the high protease producing strain was B-14, the activity of enzyme reached 2922.90U/mL which was 23.81% higher than the initial strain and showed fine stability.Conclusion B-14 high protease producing strain was obtained after selection and mutagenized by UV.