Flue-to-fuel: Bio-integrated carbon capture and utilization of dilute carbon dioxide gas streams to renewable methane

Capturing carbon dioxide (CO2) from flue gases and utilizing it as a feedstock for the production of renewable chemicals and fuels has been identified as an essential step toward mitigating climate change. Conventional CO2 capture technologies, such as amine scrubbing, are impeded by their high energy demand due to the thermodynamically low driving force for desorbing CO2. A new concept is presented here that combines carbon capture with power-to-methane: Bio-integrated carbon capture and utilization (BICCU). It exploits the robustness of microbial catalysts to simultaneously desorb the CO2 from an amine-based absorbent and convert the captured CO2 to synthetic natural gas (CH4) in a single step using renewable hydrogen. Experimental results in batch reactors with synthetic flue gas and raw flue gas from a biogas engine demonstrate high microbial biocompatibility with amine methyl diethanolamine (MDEA), high microbial robustness towards impurities and oxygen in raw flue gas, and almost full bioavailability of the absorbed CO2 until 120 mM of MDEA.