ε-聚赖氨酸高产菌选育与发酵性能评价

Breeding and fermentation performance of a high-yield ε-poly-Llysine producing strain

摘要:

[目的]选育ε-聚赖氨酸（ε-PL）高产菌，并探究不同碳源对其发酵性能的影响。[方法]借助基因组重排和核糖体工程两种育种手段强化ε-PL产生菌的合成能力，并利用pH冲击工艺评价不同碳源对ε-PL发酵的影响。[结果]经过4轮基因组重排和4轮核糖体工程连续选育，获得1株高产突变株Streptomyces albulus GS114，其摇瓶ε-PL产量达到3.0 g/L，较出发菌提高了1.7倍。该改造菌株在5 L发酵罐中分别以葡萄糖和甘油为碳源进行192 h的补料-分批发酵时，ε-PL发酵产量分别达到了43.4 g/L和45.7 g/L，较出发菌提高了11.0%和14.9%，而菌体量分别减少了24.0%和33.2%，ε-PL得率提高了34.2%和30.7%。[结论]基因组重排结合核糖体工程育种是一种有效的ε-PL高产菌选育手段，研究结果将为ε-PL高产菌改造和工业生产碳源选择提供直接指导。

Abstract:

[Objective] A high yield of ε-poly-L-lysine (ε-PL) producing strain was bred, and the effect of different carbon sources on fermentation performance was studied.[Methods] Genome shuffling and ribosome engineering were used to enhanced strain's productivity, and pH shock strategy was used to fermentation using different carbon sources.[Results] After four rounds of genome shuffling and ribosome engineering, we obtained a high yield mutant Streptomyces albulus GS114 with ε-PL productivity of 3.0 g/L, which was 1.7 folds than that of the initial strain. When we performed fed-batch fermentation using glucose and glycerol as carbon sources in a 5-L fermenter, ε-PL productions reached 43.4 and 45.7 g/L after 192 h fed-batch fermentations, which were increased by 11.0% and 14.9% than that of Streptomyces albulus M-Z18, respectively. Meanwhile, the dry cell weights decreased by 24.0% and 33.2%, and ε-PL yields increased by 34.2% and 30.7%, respectively.[Conclusion] Genome shuffling and ribosome engineering are effective to breed high yield strains.