title: Stereospecific microbial conversion of lactic acid into 1,2-propanediol.
abstract: Biocatalytic syntheses are increasingly explored as the alternate platform of chemical production in order to address the sustainable development challenge faced by the current chemical industry. Here, we report the design and implementation of an artificial pathway to convert lactic acid into 1,2-propanediol. It circumvents a highly cytotoxic intermediate that exists in a widely used natural pathway. We identified and characterized a key enzyme that catalyzed the nonnatural step of the pathway. After 72 h of cultivation under shake-flask conditions, an Escherichia coli biocatalyst expressing the artificial route synthesized 1.5 g/L of R- or 1.7 g/L of S-1,2-propanediol from D- or L- lactic acid at high enantiomeric purity, respectively. The bioconversion is part of a novel biosynthetic pathway that can be further incorporated into appropriate microbial hosts for the de novo synthesis of optically pure 1,2-propanediol from renewable feedstocks.
authors.affiliation: Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States.
authors.forename: Wei
authors.initials: W
authors.lastname: Niu
authors.affiliation: Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588, United States.
authors.forename: Jiantao
authors.initials: J
authors.lastname: Guo
mesh_terms: D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism*; D060847:Metabolic Engineering / Q000379:methods; D019946:Propylene Glycol / Q000378:metabolism*; D013237:Stereoisomerism
chemical_list: D019344:Lactic Acid; D019946:Propylene Glycol
keywords: 1,2-propanediol; artificial pathway; biocatalysis; lactic acid; stereospecific