The open circuit potential of Geobacter sulfurreducens bioanodes depends on the electrochemical adaptation of the strain

Abstract

Bioanodes for acetate oxidation were formed with pure cultures of Geobacter sulfurreducens under constant polarization potential. With the original commercial strain, the bioanodes formed at + 0.2 V/SCE exhibited open circuit potential (OCP) of 0.0 V/SCE, while the bioanodes formed at − 0.2 V/SCE had OCP around − 0.52 V/SCE. In contrast, the bioanodes formed with bacterial cells collected from a previous current-producing bioanode exhibited OCP of − 0.52 V/SCE whatever the polarization potential used to form them (+ 0.2 V/SCE or − 0.2 V/SCE). The "electrochemically-adapted strain" kept its electrochemical characteristics after successive cultures in solution. High steady-state currents were reached (16-19 A m- 2) in all cases without any dependence on strain adaptation or applied potential.