Microbial ElectroCatalytic (MEC) biofuel production

Abstract

We are developing an integrated Microbial-ElectroCatalytic (MEC) -system consisting of Ralstonia eutropha as a chemolithoautotrophic host for metabolic engineering coupled to a small-molecule electrocatalyst for the production of biofuels from CO2 and H2. R. eutropha is an aerobic bacterium that grows with CO2 as the carbon source and H2 as electron donor while producing copious amounts of polyhydroxybutyrate. Metabolic flux from existing R. eutropha pathways is being diverted into engineered pathways that produce biofuels. Novel molybdenum electrocatalysts that can convert water to hydrogen in neutral aqueous media will act as chemical mediators to generate H2 from electrodes in the presence of engineered strains of R. eutropha. To increase the local concentration of H2, we are engineering R. eutropha's outer-membrane proteins to tether the electrocatalysts to the bacterial surface. The integrated MEC system will provide a transformational new source of renewable liquid transportation fuels that extends beyond biomass-derived substrates.