Electron transfer and biofilm formation of Shewanella putrefaciens as function of anode potential

Shewanellaceae are among the most widely studied electroactive microorganisms. In this report, we studied the influence of the applied electrode potential on the anodic current production of Shewanella putrefaciens NCTC 10695 under anoxic conditions. Furthermore, we used cyclic voltammetry (CV) and confocal laser scanning microscopy (CLSM) to investigate the microbial electron transfer and biofilm formation. It is shown that the chronoamperometric current density is increasing with increasing electrode potential from 3 μA cm− 2 at − 0.1 V up to ~ 12 μA cm− 2 at + 0.4 V (vs. Ag/AgCl), which is accompanied by an increasing amount of biomass deposited on the electrode. By means of cyclic voltammetry we demonstrate that direct electron transfer (DET) is dominating and the planktonic cells play only a minor role.