Electrochemical growth of Acidithiobacillus ferrooxidans on a graphite electrode for obtaining a biocathode for direct electrocatalytic reduction of oxygen

An aspect in microbial fuel cell research that is currently of great interest is the development of bacterial cathodes. Bacterial cathodes that catalyze oxygen reduction to water at low pH have the advantage of overcoming the kinetic limitations due to the requirement of 4 protons per molecule reduced. In this work we have studied the performance of a biocathode using as electrocatalyst an acidophile microorganism: Acidithiobacillus ferrooxidans. Growth of the microorganism directly on the electrode took place using an applied voltage of 0V vs. SCE as the only energy source and without adding redox mediators to the solution. Current densities of up to 5Am-2 were measured for O2 reduction in the At. ferrooxidans cathode at pH 2.0 and the electrocatalytic wave was shifted 300mV to higher potential compared to the control graphite electrodes without the bacterium. © 2010 Elsevier B.V.We acknowledge financial support from the Comunidad de Madrid (PICOMICRO project S0505/AMB-0259), the Spanish Ministerio de Ciencia e Innovación (projects CTQ2009-12649, FUNCOAT-Consolider CSD2008-00023, MAT2007-66719-C03-01 and MAT2008-1497/nan) and the Fundación Ramón Areces.Peer Reviewe