【摘要】 在50L自控式发酵罐上进行ε-聚赖氨酸发酵条件优化研究,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-聚赖氨酸基本不合成,甚至出现降解现象;当pH维持在4.0左右时,能促进ε-聚赖氨酸的合成。搅拌转速为300r/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。更多还原

【Abstract】 Optimization of the ε-PL fermentation conditions in 50 L fermentor,the effects of pH and stirrer speed on the batch fermentation and fed-batch fermentation of ε-PL production were studied.The results showed that the growth of cells was promoted when pH remained at 5.0,but the synthesis of ε-PL was inhibited,even the accumulated ε-PL was depolymerized,while high ε-PL accumulation was achieved at pH 4.0.Under the optimal condition,In late stage,controlling pH4.0 by glucose auto-feeding and stirrer speed 350r/min,the production of ε-PL was 7.36g/L,the yield to glucose was 0.072g/g,this control and feeding strategy enhanced the production of ε-PL 11 times.更多还原