基于pH调节和有机氮源流加调控补料分批发酵过程提高ε-聚赖氨酸产量

Enhanced ε-poly-L-lysine production through pH regulation and organic nitrogen addition in fed-batch fermentation

摘要:

为了解决ε-聚赖氨酸 (ε-PL) 补料分批发酵过程中后期ε-PL产率下降的问题，提出了在补料阶段利用调节pH值和流加有机氮源 (酵母粉) 两种手段来提高ε-PL产率。利用上述两种策略，实现ε-PL平均产率分别达到4.62 g/(L·d) 和5.16 g/(L·d)，较未调控补料分批发酵 (典型补料分批发酵) 分别提高了27.3%和42.15%；同时，实现ε-PL产量分别达到36.95 g/L和41.32 g/L，较未调控补料分批发酵分别提高了27.4%和42.48%。进一步细胞活性染色和关键酶活性分析发现，两种策略均能显著提高细胞活力和关键酶活性。该研究结果表明，在发酵中后期通过调节pH值和流加酵母粉两种措施能够显著增强细胞活性和产生菌代谢能力，从而达到提高ε-PL产率和产量的目的。

Abstract:

During the production of ε-poly-L-lysine (ε-PL) in fed-batch fermentation, the decline of ε-PL synthesis often occurs at middle or late phase of the fermentation. To solve the problem, we adopted two strategies, namely pH shift and feeding yeast extract, to improve the productivity of ε-PL. ε-PL productivity in fermentation by pH shift and feeding yeast extract achieved 4.62 g/ (L·d) and 5.16 g/ (L·d), which were increased by 27.3% and 42.2% compared with the control ε-PL fed-batch fermentation, respectively. Meanwhile, ε-PL production enhanced 36.95 g/L and 41.32 g/L in 192 h with these two strategies, increased by 27.4% and 42.48% compared to the control, respectively. ε-PL production could be improved at middle or late phase of fed-batch fermentation by pH shift or feeding yeast extract.