The relay network of Geobacter biofilms

Abstract

While actual models explaining electron conduction in electricity producing biofilms have evolved separately to apparently irreconcilable conceptual positions, finding cytochrome complexes in the external matrix of Geobacter biofilms supports the proposal of a new functional model that takes fundamental elements from confronting theories. In the model that we propose here, electrons expelled by cells are conducted to the collecting electrode along a network of supramolecular cytochrome arrangements interconnected by semiconducting pilus fibres that provide equipotential conditions within physically distant points. This arrangement resembles, from our point of view, a relay network for Geobacter biofilms, which allows a concerted physiological response of the entire population to any local redox change.