title: Fermentative production of enantiomerically pure S-1,2-propanediol from glucose by engineered E. coli strain.
abstract: The pure stereoisomers of 1,2-propanediol (1,2-PDO) could be used as starting materials to synthesize high value-added specialty chemicals and chiral pharmaceutical products. As the stereoisomers of 1,2-PDO cannot be obtained by traditional chemical synthesis processes, biotechnological processes have gained increasing attention. However, to our knowledge, the production of S-1,2-PDO directly from glucose has not been previously reported. In this study, we demonstrate a novel artificial pathway to convert L-lactic acid to S-1,2-PDO and its integration into the genome of Escherichia coli strain BW25113∆poxB with synchronous deletion of genes responsible for branch metabolic pathways from glucose. L-lactate production was increased by replacing the native D-lactate dehydrogenase with the L-lactate dehydrogenase from Bacillus coagulans. The methylglyoxal bypass pathway was blocked to avoid synthesis of a racemic mixture of D- and L-lactate and prevent the accumulation of methylglyoxal, a toxic intermediate. To further improve the yield of S-1,2-PDO, a novel cofactor regeneration system was introduced by combining pyruvate decarboxylase and acetaldehyde-CoA dehydrogenase II to simultaneously regenerate NADH and the CoA donor of acetyl-CoA for the lactate conversion pathway. Finally, 13.7 mM S-1,2-PDO with >99 % enantiomeric purity was directly produced from glucose by disrupting the major carbon-competing pathways and strengthening the lactate transformation pathway. This study demonstrates the first attempt to synthesize S-1,2-PDO by direct fermentation of glucose.
authors.affiliation: CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China.|University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China.
authors.forename: Lingfeng
authors.initials: L
authors.lastname: Zhu
authors.affiliation: CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China.
authors.forename: Xiangchen
authors.initials: X
authors.lastname: Guan
authors.affiliation: National Engineering Research Center for Non-food Biorefinery, Guangxi Academy of Science, Nanning, 530007, China.
authors.forename: Nengzhong
authors.initials: N
authors.lastname: Xie
authors.affiliation: CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China.
authors.forename: Limin
authors.initials: L
authors.lastname: Wang
authors.affiliation: CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China. yub@im.ac.cn.
authors.forename: Bo
authors.initials: B
authors.lastname: Yu
authors.affiliation: Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, People's Republic of China.
authors.forename: Yanhe
authors.initials: Y
authors.lastname: Ma
mesh_terms: D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D005285:Fermentation; D005947:Glucose / Q000378:metabolism*; D060847:Metabolic Engineering; D053858:Metabolic Networks and Pathways; D019946:Propylene Glycol / Q000737:chemistry / Q000378:metabolism*; D013237:Stereoisomerism
chemical_list: D019946:Propylene Glycol; D005947:Glucose
keywords: Fermentation; Glucose; L-lactate; Metabolic engineering; S-1,2-propanediol