biostudies-literatureUnknown16(2)Ricci LCarbon dioxide (CO₂ ) stands out as sustainable feedstock for developing a circular carbon economy whose energy supply could be obtained by boosting the production of clean hydrogen from renewable electricity. H₂ -dependent CO₂ gas fermentation using acetogenic microorganisms offers a viable solution of increasingly demonstrated value. While gas fermentation advances to achieve commercial process scalability, which is currently limited to a few products such as acetate and ethanol, it is worth taking the best of the current state-of-the-art technology by its integration within innovative bioconversion schemes. This review presents multiple scenarios where gas fermentation by acetogens integrate into double-stage biotechnological production processes that usMicrobial biotechnology218-237https://www.ebi.ac.uk/biostudies/studies/S-EPMC9871533biostudies-literatureLeveraging substrate flexibility and product selectivity of acetogens in two-stage systems for chemical production.PMC9871533Seifert ARe ARicci LFino DPirri CFBernacchi SfalseLeveraging substrate flexibility and product selectivity of acetogens in two-stage systems for chemical production.Carbon dioxide (CO₂ ) stands out as sustainable feedstock for developing a circular carbon economy whose energy supply could be obtained by boosting the production of clean hydrogen from renewable electricity. H₂ -dependent CO₂ gas fermentation using acetogenic microorganisms offers a viable solution of increasingly demonstrated value. While gas fermentation advances to achieve commercial process scalability, which is currently limited to a few products such as acetate and ethanol, it is worth taking the best of the current state-of-the-art technology by its integration within innovative bioconversion schemes. This review presents multiple scenarios where gas fermentation by acetogens integrate into double-stage biotechnological production processes that us2023-01-01T00:00:00Z2023 Feb2025-08-27T03:10:47.922Z2025-04-04T13:36:28.665ZS-EPMC98715333646498010.1111/1751-7915.14172