通过对同型丝氨酸脱氢酶基因（hom）和苏氨酸合成酶基因（thrB）进行靶向破坏构建乳酸发酵短杆菌L-赖氨酸高产菌株。

Construction of L-lysine-overproducing strains of Brevibacterium lactofermentum by targeted disruption of the hom and thrB genes.

作者信息

Fernández-González C, Gil J A, Mateos L M, Schwarzer A, Schäfer A, Kalinowski J, Pühler A, Martín J F

机构信息

Departamento de Ecología, Genética y Microbiología, Facultad de Biología, Universidad de León, Spain.

出版信息

Appl Microbiol Biotechnol. 1996 Dec;46(5-6):554-8. doi: 10.1007/s002530050860.

DOI:10.1007/s002530050860

PMID:9008889

Abstract

The mobilization of plasmids from gram-negative Escherichia coli to gram-positive Brevibacterium lactofermentum, mediated by P-type transfer functions, was used to construct disrupted mutants blocked specifically in the homoserine branch of the aspartate pathway. The mutant strain B. lactofermentum R31 showed an efficiency of conjugal transfer two to three orders of magnitude higher than that of the wild-type strain B. lactofermentum ATCC 13869. The hom- and thrB-disrupted mutants of B. lactofermentum ATCC 13869 were lysine overproducers. B. lactofermentum R31 mutants do not overproduce lysine because R31 is an alanine-overproducing strain and channels the pyruvate needed for lysine biosynthesis to the production of alanine.

摘要

由P型转移功能介导，将革兰氏阴性大肠杆菌中的质粒转移至革兰氏阳性乳酸发酵短杆菌，用于构建在天冬氨酸途径的高丝氨酸分支中特异性受阻的缺失突变体。突变菌株乳酸发酵短杆菌R31的接合转移效率比野生型菌株乳酸发酵短杆菌ATCC 13869高两到三个数量级。乳酸发酵短杆菌ATCC 13869的同型丝氨酸脱氢酶基因和苏氨酸B基因缺失突变体是赖氨酸过量生产者。乳酸发酵短杆菌R31突变体不产生过量赖氨酸，因为R31是丙氨酸过量生产菌株，将赖氨酸生物合成所需的丙酮酸用于丙氨酸的生产。