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Importance of the hydrogen route in up-scaling electrosynthesis for microbial CO2reduction

Blanchet, Elise and Duquenne, François and Rafrafi, Yan and Etcheverry, Luc and Erable, Benjamin and Bergel, Alain Importance of the hydrogen route in up-scaling electrosynthesis for microbial CO2reduction. (2015) Energy & Environmental Science, 8 (12). 3731-3744. ISSN 1754-5692

(Document in English)

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Official URL: http://dx.doi.org/10.1039/C5EE03088A


Microbial electrochemical reduction of CO2 was carried out under two different applied potentials, −0.36 V and −0.66 V vs. SHE, using a biological sludge as the inoculum. Both potentials were thermodynamically appropriate for converting CO2 to acetate but only −0.66 V enabled hydrogen evolution. No acetate production was observed at −0.36 V, while up to 244 ± 20 mg L−1 acetate was produced at −0.66 V vs. SHE. The same microbial inoculum implemented in gas–liquid contactors with H2 and CO2 gas supply led to acetate production of 2500 mg L−1. When a salt marsh sediment was used as the inoculum, no reduction was observed in the electrochemical reactors, while supplying H2 + CO2 gas led to formate and then acetate production. Finally, pure cultures of Sporomusa ovata grown under H2 and CO2 gas feeding showed acetate production of up to 2904 mg L−1, higher than those reported so far in the literature for S. ovata implemented in bioelectrochemical processes. Unexpected ethanol production of up to 1411 mg L−1 was also observed. All these experimental data confirm that hydrogen produced on the cathode by water electrolysis is an essential mediator in the microbial electrochemical reduction of CO2. Implementing homoacetogenic microbial species in purposely designed gas–liquid biocontactors should now be considered as a relevant strategy for developing CO2 conversion.

Item Type:Article
Additional Information:Thanks to Royal Society of Chemistry editor. The definitive version is available at http://pubs.rsc.org The original PDF of the article can be found at Energy & Environmental Science website : http://pubs.rsc.org/en/journals/journalissues/ee#!issueid=ee008012&type=current&issnprint=1754-5692
HAL Id:hal-01304866
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
Laboratory name:
French Agence Nationale de la Recherche (ANR) - Comité des Investissements d’Avenir
Deposited On:20 Apr 2016 12:03

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