Geobacter sulfurreducens: An iron reducing bacterium that can protect carbon steel against corrosion?

The effect of Geobacter sulfurreducens on the electrochemical behaviour of carbon steel in anaerobic phosphate solution is studied here. In natural environments, G. sulfurreducens is able to reduce Fe(III) to Fe(II) during the oxidation of acetate. High availability of Fe(II) promoted the formation of an iron (II) phosphate layer on the steel. It is assumed that this phosphate layer, formed only when bacteria were present, is responsible for maintaining the corrosion potential stable even after intrusion of air. In contrast, the corrosion potential in the abiotic experiments suffered an increase of 450 mV after few hours of exposure to air. (C) 2015 Elsevier Ltd. All rights reserved.