pH调控和蔗糖流加控制对乳酸链球菌素发酵的影响

Effects of pH Control and Sucrose Feeding Rates on Nisin Production

研究了乳酸乳球菌发酵过程中pH调控和补料对产物生成的影响.研究采用三种不同的pH调控方式(初始pH7.0):(1)恒定pH6.8;(2)当pH降到6.2时恒定pH6.2;(3)发酵6h后每2h调节pH至6.8.结果表明,在发酵过程中按方式2调节pH与不调控pH相比,乳酸链球菌素效价提高了2.48倍.分别选用了4、5、6和8g.(L-1.h-1)蔗糖流加速度,当按5g.(L-1.h-1)恒速流加蔗糖溶液,乳酸链球菌素效价提高约2.9倍.

The combined effects of various pH control strategies and sucrose feeding rates on nisin production were studied. Three different pH control strategies were studied in this study （the intial pH was 7.0） ： （ 1 ） a constant pH at 6.8; （2） after pH dropped 6.2, a constant pH at 6.2; （ 3 ） after 6 h, adjusting pH at 6.8 every 2 h. The results demonstrate that nisin titer by strategy （ 2 ） yielded almost 2.6 times higher than that by strategy without pH adjustment. Sucrose feeding rates are designed at 4,5,6 and 8 g·（L-1·h-1）, respectively. Nisin titer increase about 2.9-fold by constant addition of sucrose at a feeding rate of 5 g·（L-1·h-1）.