Production of acetate from flue gas-CO2 by membrane-based bio-integrated carbon capture and utilization

Carbon Capture and Utilization (CCU) is indispensable to mitigate CO 2 emissions from hard-to-abate sectors, but its implementation is constrained by the high energy penalty associated with thermal desorption. Bio-Integrated Carbon Capture and Utilization (BICCU) is a developing technology, where microorganisms simultaneously desorb and convert captured CO 2 . This reduces the energy demand of CCU by 17–29 % and allows operation at ambient pressure and low temperatures, combined with catalytic tolerance to flue gas impurities. Recently, the membrane-based BICCU (mBICCU) concept was presented to prevent contamination of soluble bioproducts with the capture solvent, which is important for producing acetate. In this study, the mBICCU concept was applied to autotrophic monocultures of Sporomusa ovata and Acetobacterium wieringae , respectively, where CO 2 captured from a combined heat and power biogas combustion engine was the sole carbon source in the system. The homoacetogenic strains converted the captured CO 2 into acetate ( A. wieringae and S. ovata ) and ethanol ( S. ovata ), where acetate production rates reached 0.89 ± 0.05 ( S. ovata ) and 1.15 ± 0.11 ( A. wieringae ) mM h −1 . Furthermore, the rates were insignificantly different from the positive controls, where CO 2 was supplied from headspace, highlighting the potential of the mBICCU concept for supplying captured CO 2 to an acetogenic monoculture. The limiting factor for the conversion rates is proposed to be the CO 2 mass transfer rate, as an increased CO 2 -loading in the capture solvent yielded higher rates. Further advancement of the mBICCU concept would benefit directly from carbon capture, membrane processes, and gas fermentation, which all are mature technologies. • Anaerobic monocultures were for the first time cultivated on CO 2 from flue gas. • Acetogenic monocultures converted captured CO 2 into acetate in membrane bioreactors. • The CO 2 -loading in the capture solvent influenced the conversion rate. • The dissolved oxygen was <1 μM in the bioreactors and was therefore not inhibitory.