M. Willert-Porada, K. Lorenz, R. Freitag, V. Jerome, S. Peiffer
biofilm, hydrogen capture, PEM-fule cell, water cleaning
Polymer electrolyte fuel cells, PE-FC, use hydrogen or methanol as fuel. Water soluble organic compounds, like starch, glucose, acetates, can not serve as fuel because of limited catalytic activity of common metal catalysts. Opposite to metal catalysts used in PE-FC, microbial consortia are sufficiently active to extract hydrogen from organic molecules, however, the final product of this process is methane, CH4, which is too stable to be used as fuel in PE-FC. In the work presented, biofilms containing natural microbial consortia were externally grown on Gas Diffusion Electrodes (GDL), transferred from the bioreactor to a Membrane-Electrode-Assembly and operated under fuel cell conditions, using water solutions of organic substances as fuel. Hydrogen capture and „cold combustion“ is accelerated by 0.5 mg/cm² Pt on one side of the anode. The concept was proven to be successful: no methane formation occurred, up to 1.8µW/cm² at 30µA/cm² electrical power were produced with starch as fuel under sterile conditions. Growth kinetic and fuel cell performance for biofilms on different GDL’s is shown for different fuels. Activity of the biofilm is investigated by COD, LSM and Cryo-Rem measurements. The potential of „microbial fuel cells“ for waste water cleaning and power generation will be discussed.