title: Evolving the L-lysine high-producing strain of Escherichia coli using a newly developed high-throughput screening method.
abstract: This study provided a new method which applied a selected L-lysine-inducible promoter for evolving lysine industrial strains of E. coli. According to the intracellular levels of the enhanced green fluorescent protein (EGFP) whose expression was controlled by the promoter, 186 strains were preliminarily selected using fluorescence-activated cell sorting from a 10-million-mutant library generated from a L-lysine high-producing E. coli strain. By subsequent multiple parameter evaluation of the 186 selected strains according to the concentration and the yield of lysine, the productivity per unit of cell in 96-deep-well blocks, two mutants MU-1 and MU-2 were obtained. They produced 136.51 ± 1.55 and 133.2 9 ± 1.42 g/L of lysine, respectively, in 5-L jars. Compared with the lysine concentration and the yield of the original strain, those of strain MU-1 improved by 21.00 and 9.05 %, respectively, and those of strain MU-2 improved by 18.14 and 10.41 %, respectively. The mutant selection and evaluation system newly established in our study should be useful for continuous improvement of the current E. coli strains in the lysine industry.
authors.affiliation: College of Biotechnology, Tianjin University of Science and Technology, Tianjin, People's Republic of China.|Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, People's Republic of China.|Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, People's Republic of China.|Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, People's Republic of China.
authors.forename: Qinggang
authors.initials: Q
authors.lastname: Li
authors.affiliation: Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, People's Republic of China. zheng_p@tib.cas.cn.|Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, People's Republic of China. zheng_p@tib.cas.cn.
authors.forename: Ping
authors.initials: P
authors.lastname: Zheng
authors.affiliation: Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, People's Republic of China.
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, People's Republic of China.
authors.forename: Lixian
authors.initials: L
authors.lastname: Wang
authors.affiliation: College of Biotechnology, Tianjin University of Science and Technology, Tianjin, People's Republic of China.
authors.forename: Tongcun
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Systems Microbial Biotechnology, Chinese Academy of Sciences, Tianjin, People's Republic of China. sun_jb@tib.cas.cn.|Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, People's Republic of China. sun_jb@tib.cas.cn.
authors.forename: Jibin
authors.initials: J
authors.lastname: Sun
authors.affiliation: Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, People's Republic of China.
authors.forename: Yanhe
authors.initials: Y
authors.lastname: Ma
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002469:Cell Separation; D019020:Directed Molecular Evolution; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D005434:Flow Cytometry; D015723:Gene Library; D049452:Green Fluorescent Proteins / Q000032:analysis / Q000235:genetics; D057166:High-Throughput Screening Assays / Q000379:methods*; D007218:Industrial Microbiology; D008239:Lysine / Q000378:metabolism*; D011401:Promoter Regions, Genetic
chemical_list: C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D008239:Lysine
keywords: Escherichia coli; High-throughput screening; Lysine biosensor; Lysine production; Strain evolution