# Electrochemically coupled CH4 and CO2 consumption driven by microbial processes

## TL;DR

This paper shows how microbes can work with iron minerals to convert methane and carbon dioxide, helping reduce greenhouse gases in the environment.

## Contribution

The study introduces a novel microbial process that couples methane oxidation and carbon dioxide reduction using iron mineral redox cycling.

## Key findings

- Iron minerals enhance carbon fixation by acting as electron acceptors and donors in microbial processes.
- Electron flow between microbial consortia is tracked electrochemically, revealing energy metabolism at the genetic level.
- The approach offers a promising strategy for greenhouse gas removal in natural environments.

## Abstract

The chemical transformations of methane (CH4) and carbon dioxide (CO2) greenhouse gases typically have high energy barriers. Here we present an approach of strategic coupling of CH4 oxidation and CO2 reduction in a switched microbial process governed by redox cycling of iron minerals under temperate conditions. The presence of iron minerals leads to an obvious enhancement of carbon fixation, with the minerals acting as the electron acceptor for CH4 oxidation and the electron donor for CO2 reduction, facilitated by changes in the mineral structure. The electron flow between the two functionally active microbial consortia is tracked through electrochemistry, and the energy metabolism in these consortia is predicted at the genetic level. This study offers a promising strategy for the removal of CH4 and CO2 in the natural environment and proposes an engineering technique for the utilization of major greenhouse gases.

The microbial valorisation of greenhouse gases could offer promising approaches climate change mitigation. Here, authors demonstrate the coupling of methane oxidation and carbon dioxide reduction by microbial consortia, facilitated by the redox cycling of iron minerals.