Wednesday, May 7, 2008 - 10:30 AM
9-05
Enrichment of electrogenic consortia in microbial fuel cells for conversion of acetate to electricity
Abhijeet P. Borole1, Choo Hamilton1, D. Aaron2, Costas Tsouris1, David Leak3, and Thomas Fuller4. (1) Biosciences Division, Oak Ridge National Laboratory, 1-Bethel Valley Road, Bldg 1520, Rm 217, Oak Ridge, TN 37831, (2) University of Tennessee, Knoxville, TN, (3) Imperial College, London, United Kingdom, (4) Georgia Institute of Technology, Atlanta, GA
The ability to produce electricity at high power densities in microbial fuel cells (MFCs) requires optimization of biological as well as engineering parameters. Enrichment of electrogenic biofilm-forming bacteria via selective procedures, such as use of flow-through systems and removal of planktonic cells to improve power density, is demonstrated. Engineering design of the MFC targeting low ohmic and charge transfer resistances, via a three-in-one electrode design, was implemented. The progress of microbial community enrichment in the MFC was tracked via electrochemical impedance spectroscopy. Results show a decrease in the anode side resistance over time. A relationship between improvements in power density obtained over the time and the decrease in resistance was investigated. The changes appear to be mediated by the enrichment of electrode-breathing microbial systems on the anode electrode. The study was conducted using acetate as a model substrate, however, the results are applicable for other substrates including other organic acids, sugars, etc. The removal of acetate from aqueous streams has several applications including biorefineries converting biomass as well as grain to ethanol, wastewater streams from plants producing value-added bioproducts, breweries and food-based industries.