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United States Department of Agriculture

Agricultural Research Service

Research Project: ADVANCED CONVERSION TECHNOLOGIES FOR SUGARS AND BIOFUELS: SUPERIOR FEEDSTOCKS, PRETREATMENTS, INHIBITOR REMOVAL, AND ENZYMES

Location: Bioenergy Research Unit

Title: Aerated Shewanella oneidensis in Continuously-fed Bioelectrochemical Systems for Power and Hydrogen Production

Authors
item Rosenbaum, Miriam -
item Cotta, Michael
item Angenent, Lars -

Submitted to: Biotechnology and Bioengineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 23, 2009
Publication Date: February 1, 2010
Citation: Rosenbaum, M., Cotta, M.A., Angenent, L.T. 2010. Aerated Shewanella oneidensis in Continuously-fed Bioelectrochemical Systems for Power and Hydrogen Production. Biotechnology and Bioengineering. 105(5):880-888.

Interpretive Summary: Interest in the production of hydrogen as an energy source has increased markedly in recent years in response to concerns over the high cost and limited supply of petroleum. Hydrogen can be produced by fermentation of a wide variety of agricultural materials, but current technologies suffer from low yields and productivity. An alternative biological approach would be to use microbial fuel cells modified to produce hydrogen which would overcome the limitations imposed using fermentation. In the current research, the effects of aeration of the electro-active bacterium, Shewanella oneidensis, on current production, iron reduction, hydrogen production in a microbial electrolysis cell, and electric power generation in a microbial fuel cell were studied. The performance of aerated S. oneidensis was considerably enhanced compared to anaerobically grown cultures of the microbe. Biocatalyzed hydrogen production rates with aerated cultures of this organism were comparable with those reported for mixed cultures, but were about 10 times higher than reported for an anaerobic culture of S. oneidensis. The main reasons for enhanced electrochemical performance are higher levels of active biomass and more efficient substrate utilization under aerobic conditions. The next challenge will be to optimize the aeration rate of the bacterial culture to balance between maximization of bacterial activation and minimization of aerobic respiration in the culture. This research will help further the development of microbial fuel cell technology for the production of hydrogen from agricultural commodities, residues, or dedicated energy crops.

Technical Abstract: We studied the effects of aeration of Shewanella oneidensis on potentiostatic current production, iron(III) reduction, hydrogen production in a microbial electrolysis cell, and electric power generation in a microbial fuel cell. The potentiostatic performance of aerated S. oneidensis was considerably enhanced to a maximum current density of 0.45 A/m**2 or 80.3 A/m**3 (mean: 0.34 A/m**2, 57.2 A/m**3) compared to anaerobically grown cultures. Biocatalyzed hydrogen production rates with aerated S. oneidensis were studied within the applied potential range of 0.3 V to 0.9 V and were highest at 0.9 V with 0.3 m**3 H2/m**3 day, which has been reported for mixed cultures, but is ~10 times higher than reported for an anaerobic culture of S. oneidensis. Aerated microbial fuel cell experiments produced a maximum power of 3.56 W/m**3 at a 200 Ohm external resistor. The main reasons for enhanced electrochemical performance are higher levels of active biomass and more efficient substrate utilization under aerobic conditions. Coulombic efficiencies, however, were greatly reduced due to losses of reducing equivalents to aerobic respiration in the anode chamber. The next challenge will be to optimize the aeration rate of the bacterial culture to balance between maximization of bacterial activation and minimization of aerobic respiration in the culture.

Last Modified: 9/1/2014