Carbon-efficient bioconversion of methane to biofuels and biochemicals by an obligate methanotrophic bacterium

Methane, the primary component of natural gas and anaerobic digestion-derived biogas, offers a promising, high-volume petroleum replacement for fuel and chemical bioprocesses. However, the gaseous state of methane makes for a lack of compatibility with current transportation and industrial manufacturing infrastructure, limiting its utilization as a transportation fuel and intermediate in biochemical processes. Further, methane is the second most abundant greenhouse gas (GHG), with nearly 60% of emissions derived from anthropogenic sources. Up to 40M tonnes of methane (equivalent to 30% of the total US transportation fuel) is flared annually, which represents lost energy (equivalent to five quadrillion BTU of fossil fuel energy), and unnecessary GHG emissions. Microbial conversion of methane to value-added chemicals offers valorization potential, while reducing GHG emissions. Here, we demonstrate effective metabolic engineering strategies in a methanotrophic bacterium, enabling concurrent production of lipid-fuel precursors and organic acids and enhanced carbon conversion efficiency from methane to products. Additionally, we perform techno-economic analysis of methane-to-fuels and chemicals bioprocesses in order to identify key cost drivers in the valorization of methane. This work provides proof-of-concept for a transformational path to sustainable and commercially beneficial biological methane upgrading technologies.