Microbial ElectroCatalytic (MEC) Biofuel Production
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.
KeywordsBiomass Fermentation Pyridine Diesel Molybdenum
This work is funded by the ARPA-E Electrofuels program. We would also like to thank the Joint BioEnergy Institute (JBEI) for the use of its facilities and equipment; JBEI is supported by the Office of Science, Office of Biological and Environmental Research, of the U.S. Department of Energy. Work at Lawrence Berkeley National Laboratory is performed under the auspices of the U.S. Department of Energy through contract DE-AC02-05CH11231.
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