L-苯丙氨酸抗噬菌体生产菌的选育和应用

Screening of bacteriophage-resistant strain for L-phenylalanine production

为了解决噬菌体污染问题,提高L-苯丙氨酸(L-Phe)的生产稳定性,首先从L-Phe生产菌大肠杆菌WSH-Z06(pAP-B03)的异常发酵液中分离到1种噬菌体,将其命名为BP-1;再经WSH-Z06的亚硝基胍(NTG)诱变、抗性初筛、质粒pAP-B03的转化和摇瓶发酵复筛等过程,获得了1株对噬菌体BP-1不敏感的L-Phe高产菌株BR-42(pAP-B03)。在添加噬菌体的条件下的发酵中,该菌株的生长和L-Phe合成均不受影响,说明BR-42(pAP-B03)是1株可以抗噬菌体BP-1并能高产L-Phe的优良菌株,具有较大的工业生产应用价值。

To cope with the bacteriophage problem for improvement of L-Phe production, we isolated bacteriophage BP-1 from the contaminated fermentation broth of E. coli WSH-Z06 （pAP-B03） producing L-phenylalanine （L- Phe）. Through the treatment of WSH-Z06 with N-methyL-N＇ -nitro-N-nitrosoguanidine （NTG） , selection for resistance to BP-1, transformation with plasmid pAP-B03, and examination for the capacity of L-Phe production, we obtained one mutant strain E. coli BR-42 （pAP-B03）. In the presence of BP-I, E. coli BR-42 （pAP-B03） exhibited a satisfactory performance in cell growth and L- Phe production. It was confirmed that E. coli BR-42 （pAP-B03） was a potential L-Phe over-producer against bacteriophage BP-1. It could be an excellent substitute for its parent strain WSH-Z06 （pAP-B03） in L-Phe industry production.