蜡样芽孢杆菌高产新型中性蛋白酶发酵条件的优化

目的:优化蜡样芽孢杆菌发酵生产新型中性蛋白酶的培养条件。方法:采用Plackett-Burman试验设计,筛选影响蜡样芽孢杆菌高产新型中性蛋白酶酶活力的关键因子;通过Box-Behnken响应面试验设计获得新型中性蛋白酶发酵的最佳工艺条件。结果:筛选出影响蜡样芽孢杆菌高产新型中性蛋白酶的主要因子为葡萄糖、蛋白胨和pH值。获得的最优化发酵培养基组成和培养条件:葡萄糖35 g/L,蛋白40.38 g/L,氯化钠15 g/L,硫酸镁1.5 g/L,Tween-8010 g/L,装液量50 mL/250 mL,pH 7.15,菌龄12 h,发酵时间36 h。在上述条件下,蜡样芽孢杆菌发酵生产新型中性蛋白酶的酶活力高达696.51 U/mL,是未优化前的1.93倍。结论:研究结果为新型中性蛋白酶的产业化生产和应用提供了良好基础。

Optimization of Fermentation Conditions of a Novel Neutral Protease Produced by Bacillus cereus

Objective:To investigate the optimization of fermentation conditions of a novel neutral protease produced by Bacillus cereus.Methods:The Plackett-Burman design was firstly used to screen the key factors influencing the activity of the novel neutral protease produced by Bacillus cereus,and then their optimal levels were further determined through the Box-Behnken response surface experimental design.Results:The main factors affecting the activity of the novel neutral protease of Bacillus cereus were glucose,peptone and pH.The compositions of the optimized fermentation medium and culture conditions were:glucose 35 g/L,peptone 40.38 g/L,pH 7.15,sodium chloride 15 g/L,magnesium sulfate 1.5 g/L,Tween-8010 g/L,loaded volume 50 mL/250 mL,cell age 12 h,and fermentation time 36 h.Under the above conditions,the activity of the novel neutral protease produced by Bacillus cereus was up to 696.51 U/mL,a 1.93-fold increase than that in the original conditions.Conclusion:The results provide a good basis for industrial production and application of the novel neutral protease.