2007 Annual Report 1a.Objectives (from AD-416) Develop a system for the biological production of hydrogen from agricultural resources. The research is expected to produce information and technologies for the application of microbial fuel cells in the bioconversion of agricultural biomass and biomass derived carbohydrates into hydrogen that can be used as a fuel source. 1b.Approach (from AD-416) Strains of anaerobic bacteria or yeast that are known to degrade specific biomass sugars efficiently will be grown in half cells where current generation can be monitored. The electrode in the half cell will consist of carbon paper, which is attached to a potentiostat (CH Instruments). Breakdown of biomass sugars will be monitored by HPLC (1100, Hewlett-Packard). Next, electrochemically-active strains will be employed in microbial fuel cells. Several biomass sugars will be tested in the bioanode with the matching isolates present, and a potentiostat will be used to provide a minimum amount of potential to assist electrolysis in the cathode. The conversion of biomass sugars will be monitored by HPLC. The production rate of hydrogen will be monitored with a precision gas meter (MilliGascounter, Ritter) and a gas chromatograph (5890, Hewlett-Packard) and the hydrogen yield in moles of hydrogen per mole of biomass sugar degraded will be calculated. For the isolates with the highest hydrogen yield, the energy production in the electrochemically-assisted microbial fuel cell will be compared to two conventional microbial fuel cells in series connected to an electrolysis vessel. Such a system may produce enough potential to power hydrolysis without the requirement of electrochemical assistance. 3.Progress Report This report documents accomplishments under a Specific Cooperative Agreement between Agricultural Research Services (ARS) and the Washington University, St. Louis. Additional details of research can be found in the report for the parent research project 3620-41000-118-00D, entitled "Industrially Robust Enzymes and Microorganisms for Production of Sugars and Ethanol from Agricultural Biomass." Researchers are working to identify bacterial and/or yeast strains that can convert biomass sugars to hydrogen in microbial fuel cells (MFC) through an electrochemically assisted hydrogen production step. In this year of the research, two heated, continuously-fed MFC systems were designed and built that can be autoclaved for pure and bi-culture studies. The reactors are made of glass and have all the necessary ports on the anode and cathode chambers for reference electrodes and also to sample hydrogen gas in the cathode chamber. To our knowledge, this is the first continuously-fed MFC that can be maintained sterile and anaerobic, because most MFCs are operated as a batch. The MFC is being tested using pure cultures and co-cultures of anaerobic and facultative anaerobic bacteria. The Authorized Departmental Officer's Designated Representative (ADODR) monitored the activities of this agreement via e-mail contacts (weekly/monthly), phone calls, and an annual written technical report.