title: Metabolic engineering of Methanosarcina acetivorans for lactate production from methane.
abstract: We previously demonstrated anaerobic conversion of the greenhouse gas methane into acetate using an engineered archaeon that produces methyl-coenzyme M reductase (Mcr) from unculturable microorganisms from a microbial mat in the Black Sea to create the first culturable prokaryote that reverses methanogenesis and grows anaerobically on methane. In this work, we further engineered the same host with the goal of converting methane into butanol. Instead, we discovered a process for converting methane to a secreted valuable product, L-lactate, with sufficient optical purity for synthesizing the biodegradable plastic poly-lactic acid. We determined that the 3-hydroxybutyryl-CoA dehydrogenase (Hbd) from Clostridium acetobutylicum is responsible for lactate production. This work demonstrates the first metabolic engineering of a methanogen with a synthetic pathway; in effect, we produce a novel product (lactate) from a novel substrate (methane) by cloning the three genes for Mcr and one for Hbd. We further demonstrate the utility of anaerobic methane conversion with an increased lactate yield compared to aerobic methane conversion to lactate. Biotechnol. Bioeng. 2017;114: 852-861. © 2016 Wiley Periodicals, Inc.
authors: Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 168 020-4400.
authors: Michael J
authors: MJ
authors: McAnulty
authors: Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 168 020-4400.
authors: Venkata Giridhar
authors: VG
authors: Poosarla
authors: Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 168 020-4400.
authors: Jine
authors: J
authors: Li
authors: Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 168 020-4400.
authors: Valerie W C
authors: VW
authors: Soo
authors: Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 168 020-4400.
authors: Fayin
authors: F
authors: Zhu
authors: Department of Chemical Engineering, The Pennsylvania State University, University Park, Pennsylvania 168 020-4400.|Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802-4400.
authors: Thomas K
authors: TK
authors: Wood
mesh_terms: D000440:Butanols / Q000378:metabolism; D019344:Lactic Acid / Q000032:analysis / Q000378:metabolism*; D060847:Metabolic Engineering / Q000379:methods*; D008697:Methane / Q000378:metabolism*; D017020:Methanosarcina / Q000235:genetics / Q000378:metabolism*; D013237:Stereoisomerism
chemical_list: D000440:Butanols; D019344:Lactic Acid; D008697:Methane
keywords: anaerobic oxidation of methane; lactic acid; metabolic engineering