Activated Carbon and Syntrophy Accelerate the Corrosion of Stainless Steel Under Strict Anaerobic Conditions by Methanosarcina barkeri

Previous studies have demonstrated that some methanogens can directly accept electrons from Fe(0), leading to metal corrosion under strict anaerobic conditions. However, there are few reports on the research of anaerobic iron corrosion by some substances that coexist with methanogens, such as syntrophic bacteria and activated carbon, which is widely distributed in environments. Therefore, in this study, a corrosion system consisting of <i>Methanosarcina barkeri</i>, stainless steel, and granular activated carbon (GAC), as well as a corrosion system with <i>Geobacter metallireducens</i>, was constructed. The aim was to explore the mechanism of stainless steel corrosion under the metabolic action of <i>M. barkeri</i>. It was found that the GAC and <i>G. metallireducens</i> can accelerate the extracellular electron transfer between <i>M. barkeri</i> and stainless steel, thereby accelerating corrosion, and this intensification mechanism may be related to the <i>mtmC</i>, <i>mtbC</i>, and <i>fwdC</i> genes. By understanding these mechanisms, not only can a theoretical basis be provided for the protection against metal corrosion, but it can also promote environmental protection and safe production.