(139c) Bioelectrosynthetic Reduction of Carbon Dioxide to Biofuel Precursors Using a Mixed Microbial Consortium Isolated From Bovine Rumen

Microbially-catalyzed reduction of carbon dioxide to higher-molecular weight compounds through consumption of electrical current offers prospects for electrochemical production of renewable liquid transportation fuels.  Recently, pure cultures of chemoautotrophic microorganisms were reported to produce electrofuel precursors, such as acetate, from carbon dioxide and electrical current.  A consortium consisting of several different microbial populations acting as a stable community might offer an energetically favorable approach for production of these electrofuels. In order to evaluate this concept, bovine rumen contents were enriched under strict anaerobic conditions for autotrophic, acetogenic microbes for several generations using hydrogen and carbon dioxide.  A stable acetogenic consortium was obtained and transferred to bioelectrosynthesis cells supplied with electric current from a potentiostatic controller.  Current consumption and biofuel precursor production were measured. Initial electron recovery as biofuel precursors exceeded 80% efficiency.  To further improve rates and efficiency of biofuel precursor production, a combinatorial approach to evaluate growth conditions, active microbial community structure, and reactor geometry is in progress.