A Sustainable Chemicals Manufacturing Paradigm Using CO2 and Renewable H2

The chemical industry must decarbonize to align with UN Sustainable Development Goals. A shift toward circular economies makes CO 2 an attractive feedstock for producing chemicals, provided renewable H 2 is available through technologies such as supercritical water (scH 2 O) gasification. Furthermore, high carbon and energy efficiency is paramount to favorable techno-economics, which poses a challenge to chemo-catalysis. This study demonstrates continuous gas fermentation of CO 2 and H 2 by the cell factory, Cupriavidus necator , to (R,R)-2,3-butanediol and isopropanol as case studies. Although a high carbon efficiency of 0.75 [(C-mol product)/(C-mol CO 2 )] is exemplified, the poor energy efficiency of biological CO 2 fixation requires ∼8 [(mol H 2 )/(mol CO 2 )], which is techno-economically infeasible for producing commodity chemicals. Heat integration between exothermic gas fermentation and endothermic scH 2 O gasification overcomes this energy inefficiency. This study unlocks the promise of sustainable manufacturing using renewable feedstocks by combining the carbon efficiency of bio-catalysis with energy efficiency enforced through process engineering.