Oxygen traces impact on biological methanation from hydrogen and CO2

Pierre Buffière; Diana Amaya Ramirez; Ruben Teixeira Franco; Julie Figueras; Stéphane Hattou; Hassen Benbelkacem

doi:10.1016/j.biortech.2025.132080

Oxygen traces impact on biological methanation from hydrogen and CO₂

Bioresour Technol. 2025 Jan 16:419:132080. doi: 10.1016/j.biortech.2025.132080. Online ahead of print.

Authors

Pierre Buffière¹, Diana Amaya Ramirez², Ruben Teixeira Franco², Julie Figueras³, Stéphane Hattou², Hassen Benbelkacem³

Affiliations

¹ INSA Lyon, DEEP, UR7429 69621 Villeurbanne Cedex, France. Electronic address: pierre.buffiere@insa-lyon.fr.
² Arkolia Energies, 16 Rue Des Vergers 34130 Mudaison, France.
³ INSA Lyon, DEEP, UR7429 69621 Villeurbanne Cedex, France.

PMID: 39826758
DOI: 10.1016/j.biortech.2025.132080

Abstract

Biomethane production from biological methanation of CO₂ is promising both for biogas upgrading and surplus renewable energy storage. One of the questions for process upscaling is the impact of oxygen (in the biogas or in the purified CO₂-rich off-gas) on the biological process. An adapted anaerobic thermophilic consortium was submitted to increasing amounts of oxygen in batch and continuous tests at partial pressures ranging from 0 to 50 mbar. Oxygen was quickly consumed and hydrogen uptake remained similar. In the same time, methane production dropped (-4 % in continuous tests). Part of the oxygen introduced was reduced biologically by hydrogen. The amount of hydrogen diverted to oxygen reduction (up to 15 % at 50 mbar O₂) was proportional to the oxygen partial pressure. These results suggest that biological methanation systems tolerate the presence of oxygen. However, additional hydrogen should be added to maintain the conversion of CO₂ into methane.

Keywords: Biological methanation; Biomethane; Hydrogen conversion; Oxygen.