[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.