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

## TL;DR

This study shows that Methanosarcina barkeri, along with activated carbon and Geobacter metallireducens, can accelerate stainless steel corrosion under anaerobic conditions.

## Contribution

The study identifies how syntrophy and activated carbon enhance corrosion via electron transfer mechanisms involving specific genes.

## Key findings

- Granular activated carbon and Geobacter metallireducens enhance electron transfer between Methanosarcina barkeri and stainless steel.
- The mtmC, mtbC, and fwdC genes may be involved in the corrosion acceleration mechanism.
- This mechanism contributes to understanding anaerobic metal corrosion and its prevention.

## Abstract

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 Methanosarcina barkeri, stainless steel, and granular activated carbon (GAC), as well as a corrosion system with Geobacter metallireducens, was constructed. The aim was to explore the mechanism of stainless steel corrosion under the metabolic action of M. barkeri. It was found that the GAC and G. metallireducens can accelerate the extracellular electron transfer between M. barkeri and stainless steel, thereby accelerating corrosion, and this intensification mechanism may be related to the mtmC, mtbC, and fwdC 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.