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  • Metabolic engineering of Methanosarcina acetivorans for lactate production from methane.

Metabolic engineering of Methanosarcina acetivorans for lactate production from methane.

Biotechnology and bioengineering (2016-11-02)
Michael J McAnulty, Venkata Giridhar Poosarla, Jine Li, Valerie W C Soo, Fayin Zhu, Thomas K Wood
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.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Sodium fumarate dibasic, ≥99%
Sigma-Aldrich
3-Hydroxybutyric acid, 95%
Sigma-Aldrich
Lithium L-lactate, ≥98% (titration)
Sigma-Aldrich
Crotonic acid, 98%
Supelco
Metal Packed GC Column (General Configuration), phase none, matrix 60/80 Carboxen-1000 support, L × O.D. × I.D. 15.0 ft (4.6 m) × 1/8 in. × 2.1 mm
Sigma-Aldrich
Lithium acetoacetate, ≥90% (HPLC)