利用三阶段葡萄糖添加策略减少乙酸合成并促进重组大肠杆菌生产L-苯丙氨酸

Decreased acetic acid synthesis and enhanced L-phenylalanine production by E.coli WSH-Z06(pAP-B03) using three stage glucose feeding strategy

为了降低副产物乙酸的积累和提高L-苯丙氨酸的产量,分别优化了L-苯丙氨酸发酵的初始葡萄糖浓度和葡萄糖的指数流加策略。结果表明,20 g/L的初始葡萄糖浓度可以控制细胞的比生长速率低于临界值0.3 h-1,显著地降低了乙酸的积累,提高了L-苯丙氨酸的产量。采用预设比生长速率μ3 *=0.4(h-1)进行葡萄糖的指数流加取得了实际最大比生长速率0.29 h-1,使细胞的比生长速率低于临界值,促进了L-苯丙氨酸的合成,最终获得L-苯丙氨酸的产量达48.45g/L,比本实验室原有水平提高了37%。

In order to minimize the accumulation of acetic acid and enhance the production of L-phenylalanine, the initial glucose concentration and the exponential feeding strategy were optimized. The results indicate that initial glucose concentration of 20 g/L could control the cell specific growth acetic acid accumulation and promoting L-Phe production not only benefit cell growth , but also control cell specific rate below the critical value of 0.3 h-1 , greatly lowering the The exponential feeding strategy with μ3＇=0.4（h-1） could rate within critical value, yielding L-Phe titer of 48.45 g/L, exhibiting 37% increase compared to the previously reported value in our lab.