5 L发酵罐中粪肠球菌发酵工艺参数优化

Optimization of the fermentation parameters for Enterococcus faecalis in 5 L bioreactor

本试验旨在通过单因素试验及Box-Behnken响应面试验设计法优化饲用粪肠球菌EXW 27发酵工艺,探索搅拌速度、中和剂、pH、接种量、初始糖含量、通气方式以及补料工艺等对菌体在发酵罐内生长的影响。优化菌体小试发酵工艺为:将种子液以3%(V/V)接种于装液量为70%的5 L小罐,发酵温度37℃,搅拌转速165 r/min,通空气保压0.02 Mpa,自动流加12.5%的氨水控制pH在5.5,当pH高于5.5流加葡萄糖补料发酵18 h左右结束,在此最佳条件下所得发酵液的活菌浓度约为3.799×10^10 cfu/mL,比优化前提高了近3倍,为以后工业化生产提供参考。

This experiment was designed to optimize the fermentation process of feeding Enterococcus faecalis EXW 27 by single factor test and box-behnken response surface test design method,and to explore the influence of stirring speed,neutralizer,pH,inoculation amount,initial sugar content,ventilation method and feeding process on the growth of bacteria in the fermentation tank.The optimum pilot fermentation process for Enterococcus faecalis EXW 27 were as follows:inoculating the seed liquid(3%V/V)into cannikin with medium volume of 70%,fermentation temperature 37℃,stirring speed 165 r/min,air pressure 0.02 Mpa,automatic flow plus 12.5%ammonia to maintain the pH of medium at 5.5.When the pH was more than 5.5,the fermentation was completed after 18 h with glucose supplemental feed.Under the best conditions,the live bacteria concentration of fermented liquid was about 3.799×10^10 cfu/mL,nearly three times higher than that of before optimization.This study provided a powerful model for industrial production.