食品科学2017，Vol.38Issue(4)：32-38,7.DOI:10.7506/spkx1002-6630-201704006
基于基因转录和代谢物分析的异亮氨酸生产菌谷氨酸棒状杆菌YILW的理性改造
Rational Design of Corynebacterium glutamicum YILW for Isoleucine Production Based on Gene Transcription and Metabolite Analysis
摘要
Abstract
This study aimed to rationally identify new targets for improving isoleucine production.The transcription levels of the key genes and intermediate metabolite levels involved in the isoleucine synthesis pathway of Corynebacterium glutamicum ATCC 13032 and C.glutamicum YILW,a isoleucine-producing strain derived from the parental strain ATCC 13032,were compared.The gene pyc was down-regulated,which might consequently lead to reduced supply of oxaloacetate.Then pyc was overexpressed in C.glutamicum YILW (denoted as YILW-1),resulting in increased oxaloacetate concentration and isoleucine production (from 1.32 to 3.32 μmol/g (md) and from 5.18 to 5.81g/L) but higher accumulation of lysine and intracellular 2-ketobutyrate as byproduct.The ilvBNC operon was further overexpressed in YILW-1 (denoted as YILW-2),resulting in production of up to 6.63 g/L isoleucine.To enhance exportation and consequently further increase the production of isoleucine,the isoleucine exporter genes brnE and brnF was overexpressed in YILW-2 (denoted as YILW-3),leading to increased production of isoleucine (7.31 g/L) by 10.3％ as compared to that of YILW-2.The strategy resulted in 41.1％ higher isoleucine production (from 5.18 to 7.31 g/L) and 40.0％ higher yield (from 0.10 to 0.14 g/g glucose) together with lower by-product lelvels by YILW-3 as compared to C.glutamicum YILW.It could be concluded that overexpression of the pyc,ilvBNC operon as well as brnE and brnF based on transcription and metabolite pool analysis could significantly elevate isoleucine production and decrease by-product concentration levels.关键词
谷氨酸棒杆菌/异亮氨酸/代谢库/草酰乙酸Key words
Corynebacterium glutamicum/isoleucine/metabolite pool/oxaloacetate分类
生物科学引用本文复制引用
温冰,麻杰,李智祥,张成林,徐庆阳,陈宁..基于基因转录和代谢物分析的异亮氨酸生产菌谷氨酸棒状杆菌YILW的理性改造[J].食品科学,2017,38(4):32-38,7.基金项目
国家高技术研究发展计划(863计划)项目(2013AA102106) （863计划）
国家自然科学基金青年科学基金项目(31300069) （31300069）
天津市科技特派员项目(15JCTPJC62800) （15JCTPJC62800）
