葡萄糖发酵生产ε-聚赖氨酸工艺优化

Optimization of ε-poly-L-lysine production with glucose as carbon source by Streptomyces albulus M-Z18

为建立Streptomyces albulus M-Z18以葡萄糖为碳源的ε-聚赖氨酸(ε-PL)高效发酵工艺,对葡萄糖和硫酸铵的流加方式和控制浓度、pH控制条件和溶氧控制水平进行了系统研究。研究结果表明,葡萄糖补料采用脉冲补料方式控制维持在10~30 g/L范围,氨氮补料采用脉冲补料方式维持在0.1~0.5 g/L范围,pH冲击时间为9 h、恢复pH为3.85,发酵中后期最佳溶氧水平为20%左右为最优ε-PL发酵工艺控制条件。经过8天补料-分批发酵,实现ε-PL产量达到47.13 g/L,菌体量为57.08 g/L,相比于优化前,ε-PL产量和菌体量分别提高了27.34%和19.61%。上述研究结果为ε-PL工业化生产奠定了基础。

To develop an efficient ε-poly-L-lysine（e-PL）fermentation process of Streptomyces albulus M-Z18 with glucose as carbon source, feeding approaches and concentrations of glucose and ammonium sulfate, pH control strategy and the level of dissolved oxygen were investigated systematically in this study. The optimal conditions of ε-PL fermentation were established as following： the concentrations of glucose and ammonia nitrogen were maintained in the range of 10 - 30 g/L and 0.1 - 0.5 g/L by pulse feeding mode, respectively ; the pH shock time was lasted 9 h and the recovery pH was set to 3.85 ; and the optimal dissolved oxygen level in the middle and later stage of fermentation was about 20%. After 8 days of fed-batch fermentation, the ε-PL production and biomass reached 47.13 g/L and 57. 08 g/L, respectively. Compared with those of the non-optimized fermentation, the ε-PL production was increased by 27.34% and the biomass was enhanced by 19.61%. Obviously, the results of this study laid the foundation for the industrial production of ε-PL.