酪氨酸流加方式对重组大肠杆菌发酵生产L-苯丙氨酸的影响

摘要

研究了流加浓度对酪氨酸重组大肠杆菌Escherichia coli BR-165(pAP-B03)发酵生产L-苯丙氨酸的影响.结果表明,诱导后L-酪氨酸流加加速了菌体的生长,提高了生产强度,缩短了发酵周期.在流加浓度为75 mg/h时,最大菌体干重达到了40.13 g/L(对照11.48 g/L),生产周期缩短到30 h(对照48 h),生产强度达到1.409 g/h/L(对照0.876 g/h/L).但是L-酪氨酸的流加对L-苯丙氨酸的最终产量没有明显的影响,因此可认为流加酪氨酸是减少发酵时间并提高生产强度的有效方法.本研究获得的酪氨酸流加方式对L-苯丙氨酸的工业化生产具有一定的指导意义.%The influence of feeding L-tyrosine (L-Tyr) at different rates during induction phase (after 12 h) on the production of L-phenylalanine (L-Phe) by an L-Tyr auxotrophic Escherichia coli BR-165 (pAP-B03) was investigated. Three feeding rates including 25 mg/h, 50 mg/h and 75 rng/h were examined. The results showed that in comparison with the control (without L-Tyr feeding) , the feeding of concentrated L-Tyr increased cell growth rate and L-Phe productivity. At a feeding rate of 75 mg/h, the dry cell weight (DCW) increased from 11.48 g/L of the control to 40.13g/L, and the fermentation time decreased from 48 h of the control to 30 h, and the L-Phe productivity increased from 0. 876 g/h/L of the control to 1.409 g/h/L. However, the feeding of L-Tyr had little influence on the final L-Phe titer, which remained the same as the control. It indicated that feeding L-Tyr at a suitable rate during induction phase was an effective approach to reduce fermentation time and to increase L-Phe productivity. The results may be useful for the industrial production of L-Phe.