Research advances of microbial transformation of CO2 in geological sequestration

Abstract:

Carbon capture, utilization and storage is the vital technology for China to achieve the goals of carbon peaking and carbon neutrality. Microbial activities in situ are an indispensable part in the process of geological CO₂ sequestration. Some microorganisms can convert CO₂ into methane and organics as the resource for utilization or into carbonate to achieve long-term sequestration. These activities contribute to the stable storage of CO₂ and even negative carbon emission. This paper focuses on the processes of bio-methanation, bio-liquefaction, and bio-precipitation that may be involved in CO₂ sequestration in deep stratum and discusses the research progress in the bio-transformation pathways. Bio-methanation and bio-liquefaction can convert CO₂ into methane or high-value organic compounds to realize resource reuse. The two technologies can be used alone or coupled to expand the application range of CO₂ biotransformation. Bio-mineralization can convert CO₂ into calcite by microorganism-induced carbonate precipitation, being a technology of great potential in fixing CO₂ and limiting CO₂ escape. At present, this field is still in the infancy stage, and there is an urgent need to establish and improve the theoretical and technical systems of CO₂ in-situ biotransformation from transformation principle, influencing factors, conversion efficiency, economy, environmental protection, and technological conditions. Moreover, it can be combined with CCUS to establish a technical system integrating capture, transport, displace, storage, transfer, and exploit, so as to promote the value-added application of CCUS and the achievement of carbon peaking and carbon neutrality.