Microbial electrosynthesis of butyrate from carbon dioxide: Production and extraction

Pau Batlle-Vilanova; Ramon Ganigué; Sara Ramió-Pujol; Lluís Bañeras; Gerard Jiménez; Manuela Hidalgo; M Dolors Balaguer; Jesús Colprim; Sebastià Puig

doi:10.1016/j.bioelechem.2017.06.004

Microbial electrosynthesis of butyrate from carbon dioxide: Production and extraction

Bioelectrochemistry. 2017 Oct:117:57-64. doi: 10.1016/j.bioelechem.2017.06.004. Epub 2017 Jun 15.

Authors

Pau Batlle-Vilanova¹, Ramon Ganigué², Sara Ramió-Pujol³, Lluís Bañeras⁴, Gerard Jiménez⁵, Manuela Hidalgo⁶, M Dolors Balaguer⁵, Jesús Colprim⁷, Sebastià Puig⁵

Affiliations

¹ LEQUiA, Institute of the Environment, University of Girona, Campus Montilivi, Carrer Maria Aurèlia Capmany, 69, E-17003 Girona, Catalonia, Spain; FCC Aqualia, Department of Innovation and Technology, Balmes Street, 36, 6th Floor, 08007 Barcelona, Spain.
² LEQUiA, Institute of the Environment, University of Girona, Campus Montilivi, Carrer Maria Aurèlia Capmany, 69, E-17003 Girona, Catalonia, Spain; Center for Microbial Ecology and Technology (CMET), Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
³ LEQUiA, Institute of the Environment, University of Girona, Campus Montilivi, Carrer Maria Aurèlia Capmany, 69, E-17003 Girona, Catalonia, Spain; Group of Molecular Microbial Ecology, Institute of Aquatic Ecology (IEA), University of Girona, Campus Montilivi, E-17003 Girona, Catalonia, Spain.
⁴ Group of Molecular Microbial Ecology, Institute of Aquatic Ecology (IEA), University of Girona, Campus Montilivi, E-17003 Girona, Catalonia, Spain.
⁵ LEQUiA, Institute of the Environment, University of Girona, Campus Montilivi, Carrer Maria Aurèlia Capmany, 69, E-17003 Girona, Catalonia, Spain.
⁶ Department of chemistry, University of Girona, Campus Montilivi, E-17003 Girona, Catalonia, Spain.
⁷ LEQUiA, Institute of the Environment, University of Girona, Campus Montilivi, Carrer Maria Aurèlia Capmany, 69, E-17003 Girona, Catalonia, Spain. Electronic address: j.colprim@lequia.udg.cat.

PMID: 28633067
DOI: 10.1016/j.bioelechem.2017.06.004

Abstract

To date acetate is the main product of microbial electrosynthesis (MES) from carbon dioxide (CO₂). In this work a tubular bioelectrochemical system was used to carry out MES and enhance butyrate production over the other organic products. Batch tests were performed at a fixed cathode potential of -0.8V vs SHE. The reproducibility of the results according to previous experiments was validated in a preliminary test. According to the literature butyrate production could take place by chain elongation reactions at low pH and high hydrogen partial pressure (p_H2). During the experiment, CO₂ supply was limited to build up p_H2 and trigger the production of compounds with a higher degree of reduction. In test 1 butyrate became the predominant end-product, with a concentration of 59.7mMC versus 20.3mMC of acetate, but limitation on CO₂ supply resulted in low product titers. CO₂ limitation was relaxed in test 2 to increase the bioelectrochemical activity but increase p_H2 and promote the production of butyrate, what resulted in the production of 87.5mMC of butyrate and 34.7mMC of acetate. The consumption of ethanol, and the presence of other products in the biocathode (i.e. caproate) suggested that butyrate production took place through chain elongation reactions, likely driven by Megasphaera sueciensis (>39% relative abundance). Extraction and concentration of butyrate was performed by liquid membrane extraction. A concentration phase with 252.4mMC of butyrate was obtained, increasing also butyrate/acetate ratio to 16.4. The results are promising for further research on expanding the product portfolio of MES.

Keywords: Bioproduction; CO(2) utilisation; Clostridium autoethanogenum; Hydrogen partial pressure.

MeSH terms

Bioreactors / microbiology*
Butyric Acid / isolation & purification*
Butyric Acid / metabolism*
Carbon Dioxide / metabolism*
Electrochemistry
Electrodes
Electron Transport

Substances

Butyric Acid
Carbon Dioxide