title: [High-efficiency L-lactate production from glycerol by metabolically engineered Escherichia coli].
abstract: High-efficient conversion of glycerol to L-lactate is beneficial for the development of both oil hydrolysis industry and biodegradable materials manufacturing industry. In order to construct an L-lactate producer, we first cloned a coding region of gene BcoaLDH encoding an L-lactate dehydrogenase from Bacillus coagulans CICIM B1821 and the promoter sequence (P(ldhA)) of the D-lactate dehydrogenase (LdhA) from Escherichia coli CICIM B0013. Then we assembled these two DNA fragments in vitro and yielded an expression cassette, P(ldhA)-BcoaLDH. Then, the cassette was chromosomally integrated into an ldhA mutant strain, Escherichia coli CICIM B0013-080C, by replacing lldD encoding an FMN-dependent L-lactate dehydrogenase. An L-lactate higher-producer strain, designated as E. coli B0013-090B, possessing genotype of lldD::P(ldhA)-BcoaLDH, deltaack-pta deltapps deltapflB deltadld deltapoxB deltaadhE deltafrdA and deltaldhA, was generated. Under the optimal condition, 132.4 g/L L-lactate was accumulated by B0013-090B with the lactate productivity of 4.90 g/Lh and the yield of 93.7% in 27 h from glycerol. The optical purity of L-lactate in broth is above 99.95%.
authors.affiliation: School of Biotechnology, Jiangnan University, Wuxi 214122, Jiangsu, China.
authors.forename: Kangming
authors.initials: K
authors.lastname: Tian
authors.affiliation: National Engineering Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi 214122, Jiangsu, China.
authors.forename: Guiyang
authors.initials: G
authors.lastname: Shi
authors.affiliation: College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China.
authors.forename: Fuping
authors.initials: F
authors.lastname: Lu
authors.affiliation: Faculty of Applied Sciences, Department of Biotechnology & Food Technology, Durban University of Technology, PO Box 1334, Durban 4001, South Africa.
authors.forename: Suren
authors.initials: S
authors.lastname: Singh
authors.affiliation: College of Biotechnology, Tianjin University of Science & Technology, Tianjin 300457, China.
authors.forename: Zhengxiang
authors.initials: Z
authors.lastname: Wang
mesh_terms: D001407:Bacillus / Q000201:enzymology; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D005990:Glycerol / Q000378:metabolism*; D007770:L-Lactate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D019344:Lactic Acid / Q000096:biosynthesis*; D060847:Metabolic Engineering; D011401:Promoter Regions, Genetic / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D011994:Recombinant Proteins; D019344:Lactic Acid; D007770:L-Lactate Dehydrogenase; D005990:Glycerol