Publication Details |
| Category | Text Publication |
| Reference Category | Journals |
| DOI | 10.1021/acssuschemeng.1c05133 |
| Document | accepted manuscript |
| Title (Primary) | Recirculation of H2, CO2, and ethylene improves carbon fixation and carboxylate yields in anaerobic fermentation |
| Author | Baleeiro, F.C.F.; Kleinsteuber, S.
; Sträuber, H. |
| Source Titel | ACS Sustainable Chemistry & Engineering |
| Year | 2022 |
| Department | UMB |
| Volume | 10 |
| Issue | 13 |
| Page From | 4073 |
| Page To | 4081 |
| Language | englisch |
| Topic | T7 Bioeconomy |
| Supplements | https://pubs.acs.org/doi/suppl/10.1021/acssuschemeng.1c05133/suppl_file/sc1c05133_si_001.pdf |
| Keywords | mixotrophy; volatile fatty acids; medium-chain carboxylic acids; carbon capture; methanogenesis inhibition; syngas fermentation; acetogenesis; Wood−Ljungdahl pathway |
| Abstract | Anaerobic fermentation with mixed cultures has gained momentum as a bioprocess for its promise to produce platform carboxylates from low-value biomass feedstocks. Anaerobic fermenters are net carbon emitters, and their carboxylate yields are limited by electron donor availability. In a new approach to tackle these two disadvantages, we operated two bioreactors at pH 6.0 and 32 °C fed with acetate and lactate as a model feedstock while recirculating H2/CO2 to stimulate concomitant autotrophic activity. After 42 days of operation, hydrogenotrophic methanogenesis was predominant, and ethylene (≥1.3 kPa) was added to one of the reactors, inhibiting methanogenesis completely and recovering net carbon fixation (0.20 g CO2 L–1 d–1). When methanogenesis was inhibited, exogenous H2 accounted for 17% of the consumed electron donors. The lactate-to-butyrate selectivity was 101% (88% in the control without ethylene), and the lactate-to-caproate selectivity was 17% (2.3% in the control). Community analysis revealed that ethylene caused Methanobacterium to be washed out, giving room to acetogenic bacteria. In contrast to 2-bromoethanosulfonate, ethylene is a scalable methanogenesis inhibition strategy that did not collaterally block i-butyrate formation. By favoring the bacterial share of the community to become mixotrophic, the concept offers a way to simultaneously increase the selectivity to medium-chain carboxylates and develop a carbon-fixing chain elongation process. |
| Persistent UFZ Identifier | https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=25948 |
| Baleeiro, F.C.F., Kleinsteuber, S., Sträuber, H. (2022): Recirculation of H2, CO2, and ethylene improves carbon fixation and carboxylate yields in anaerobic fermentation ACS Sustain. Chem. Eng. 10 (13), 4073 - 4081 10.1021/acssuschemeng.1c05133 |
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