50L自控式发酵罐中ε-聚赖氨酸发酵条件的优化

在50L自控式发酵罐上进行了ε-聚赖氨酸(ε-PL)发酵条件的优化研究,主要考察了分批发酵和补料分批发酵过程中pH、搅拌转速对ε-PL发酵和菌体生长的影响。结果表明,当控制pH在5.0以上时有利于菌体的生长,但ε-PL基本不合成,甚至出现降解现象;当维持pH在4.0左右时,能促进ε-PL的合成。搅拌转速为300 r/min时,有利于溶氧和传质,400r/min时,由于剪切力过大,导致菌丝断裂,ε-PL产量下降。通过控制发酵中后期pH4.0和搅拌转速300r/min的pH反馈控制自动流加补料培养,可获得最大的ε-PL产量7.36g/L,产率0.072g/g,产量较优化前提高近10倍,产率提高2倍。

Optimization of the ε-Poly-L-lysine Fermentation Conditions in 50 L Fermentor

In order to optimize theε-poly-L-lysine(ε-PL) fermentation conditions in a 50 L fermentor,the effects of pH and stirrer speed on the batch fermentation and fed—batch fermentation ofε-PL production were studied.The results showed that the growth of cells was promoted when pH remained at 5.0,the syn- thesis ofε-PL was inhibited,the accumulatedε-PL was depolymerized,and highε-PL accumulation was a- chieved at pH 4.0.Under the optimal condition,controlling pH 4.0 by glucose auto-feeding and stirrer speed 350r/min at later stage,the production ofε-PL was 7.36g/L,the yield to glucose was 0.072g/g.This con- trol and feeding strategy enhanced the production ofε-PL 11 times.