Stepping stones in the electron transport from cells to electrodes in Geobacter sulfurreducens biofilms

BONANNI P. SEBASTIAN; MASSAZZA DIEGO; BUSALMEN JUAN PABLO

PHYSICAL CHEMISTRY CHEMICAL PHYSICS

ROYAL SOC CHEMISTRY

Lugar: CAMBRIDGE; Año: 2013 vol. 15 p. 10300 - 10306

1463-9076

Geobacter sulfurreducens bacteria grow on biofilms and have the particular ability of using polarized electrodes as the final electron acceptor of their respiratory chain. In these biofilms, electrons are transported through distances of more than 50μm before reaching the electrode. The way in which electrons are transported across the biofilm matrix through such large distances remains under intense discussion. None of the two mechanisms proposed for explaining the process, electron hopping through outer membrane cytochromes and metallic like conduction through conductive PilA filaments, can account for all the experimental evidences collected so far. Aiming at providing new elements for understanding the basis for electron transport, in this perspective article we present a modelled structure of Geobacter pilus. Its analysis in combination with already existing experimental evidence gives support to the proposal of the ?stepping stone? mechanism, in which the combined action of pili and cytochromes allows long range electron transport through the biofilm.