Novel strain induces severe corrosion by retrieving electrons from Fe under a freshwater environment

Hirano, Shinichi*; Ihara, Sota*; Wakai, Satoshi*; Dotsuta, Yuma; Otani, Kyohei   ; Kitagaki, Toru  ; Ueno, Fumiyoshi  ; Okamoto, Akihiro*

To understand the role of methanogens in corrosion under anoxic conditions in freshwater, we investigated the corrosion activities of methanogens in samples collected from groundwater and rivers. We enriched microorganisms that can grow with CO/NaHCO and Fe as the sole carbon source and electron donor, respectively, in ground fresh water. Electrochemical analysis revealed that strain can uptake electrons from the cathode at lower than -0.61 V vs SHE and has a redox-active component with electrochemical potential different from those of other previously reported methanogens with extracellular electron transfer ability. This study indicated the corrosion risk by methanogens capable of taking up electrons from Fe in anoxic freshwater environments and the necessity of understanding the corrosion mechanism to contribute to risk diagnosis.