The effect of the polarised cathode, formate and ethanol on chain elongation of acetate in microbial electrosynthesis
The effect of the polarised cathode, formate and ethanol on chain elongation of acetate in microbial electrosynthesis
Reduction of CO2 to acetate in microbial electrosynthesis has been widely studied. However, the selective and quantitative production of longer chain chemicals and biofuels is still a bottleneck. Lack of sufficient energy provided by only the cathode electrode in Bio-electrochemical systems during chain elongation is one of the key challenges. It is assumed that additional electron donors than a polarised cathode is required to steer the production towards longer chain of carboxylates than acetate. In this study, formate and ethanol were supplied separately in the reactors fed by CO2 for 45 days in addition to the cathodes poised at −1.0 V vs. Ag/AgCl to investigate their effect on production. Although acetate was still the major product, supplying electron donors directed the production towards more diverse and longer chain organic chemicals than that in presence of the polarised cathode only. Significant improvement in the production of butyrate (×3.8 increase in maximum concentration) and butanol (maximum of 6.8 ± 0.3 mmol C L−1) was observed after supplying formate, while ethanol increased the diversity of the products. Supplying formate and ethanol in reactors for another 30 days under open circuit potential clarified that only ethanol could provide sufficient energy for butyrate production from acetate in the absence of polarised cathode, which reached the highest butyrate concentration of 19.1 ± 2.3 mmol C L−1. Formate was only consumed in presence of polarised cathode. It is proposed in our study that production of C4 products in presence of only cathodic electrode or cathodic electrode and formate could be associated to initial reduction of acetate to ethanol, consumed for production of C4 products through acetate. Trace levels of caproate and hexanol were detected in both reactors supplied with formate and ethanol only in the presence of polarised cathode.
Biocathode, Electro-fermentation, Electron donors, Ethanol, Formate, Microbial electrosynthesis
Izadi, Paniz
0fda147e-44cf-4480-b72b-c3303c570573
Fontmorin, Jean Marie
5bf4da48-91b0-4548-a4ef-c5dd8e0b630c
Virdis, Bernardino
6b59b1f3-782c-4451-b323-d18c103f0710
Head, Ian M.
45e5ea84-bd86-4ffd-a6e3-64b23dc711d2
Yu, Eileen H.
28e47863-4b50-4821-b80b-71fb5a2edef2
18 January 2021
Izadi, Paniz
0fda147e-44cf-4480-b72b-c3303c570573
Fontmorin, Jean Marie
5bf4da48-91b0-4548-a4ef-c5dd8e0b630c
Virdis, Bernardino
6b59b1f3-782c-4451-b323-d18c103f0710
Head, Ian M.
45e5ea84-bd86-4ffd-a6e3-64b23dc711d2
Yu, Eileen H.
28e47863-4b50-4821-b80b-71fb5a2edef2
Izadi, Paniz, Fontmorin, Jean Marie, Virdis, Bernardino, Head, Ian M. and Yu, Eileen H.
(2021)
The effect of the polarised cathode, formate and ethanol on chain elongation of acetate in microbial electrosynthesis.
Applied Energy, 283, [116310].
(doi:10.1016/j.apenergy.2020.116310).
Abstract
Reduction of CO2 to acetate in microbial electrosynthesis has been widely studied. However, the selective and quantitative production of longer chain chemicals and biofuels is still a bottleneck. Lack of sufficient energy provided by only the cathode electrode in Bio-electrochemical systems during chain elongation is one of the key challenges. It is assumed that additional electron donors than a polarised cathode is required to steer the production towards longer chain of carboxylates than acetate. In this study, formate and ethanol were supplied separately in the reactors fed by CO2 for 45 days in addition to the cathodes poised at −1.0 V vs. Ag/AgCl to investigate their effect on production. Although acetate was still the major product, supplying electron donors directed the production towards more diverse and longer chain organic chemicals than that in presence of the polarised cathode only. Significant improvement in the production of butyrate (×3.8 increase in maximum concentration) and butanol (maximum of 6.8 ± 0.3 mmol C L−1) was observed after supplying formate, while ethanol increased the diversity of the products. Supplying formate and ethanol in reactors for another 30 days under open circuit potential clarified that only ethanol could provide sufficient energy for butyrate production from acetate in the absence of polarised cathode, which reached the highest butyrate concentration of 19.1 ± 2.3 mmol C L−1. Formate was only consumed in presence of polarised cathode. It is proposed in our study that production of C4 products in presence of only cathodic electrode or cathodic electrode and formate could be associated to initial reduction of acetate to ethanol, consumed for production of C4 products through acetate. Trace levels of caproate and hexanol were detected in both reactors supplied with formate and ethanol only in the presence of polarised cathode.
Text
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Accepted/In Press date: 14 November 2020
e-pub ahead of print date: 2 December 2020
Published date: 18 January 2021
Keywords:
Biocathode, Electro-fermentation, Electron donors, Ethanol, Formate, Microbial electrosynthesis
Identifiers
Local EPrints ID: 498886
URI: http://eprints.soton.ac.uk/id/eprint/498886
ISSN: 0306-2619
PURE UUID: 6a8f4583-fef9-4b2e-9c7e-30ac9b610f38
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Date deposited: 04 Mar 2025 17:51
Last modified: 22 Aug 2025 02:45
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Contributors
Author:
Paniz Izadi
Author:
Jean Marie Fontmorin
Author:
Bernardino Virdis
Author:
Ian M. Head
Author:
Eileen H. Yu
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