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Bidirectional microbial electron transfer: Switching an acetate oxidizing biofilm to nitrate reducing conditions

Up to date a few electroactive bacteria embedded in biofilms are described to catalyze both anodic and cathodic reactions in bioelectrochemical systems (i.e. bidirectional electron transfer). How these bacteria transfer electrons to or from the electrode is still uncertain. In this study the extracellular electron transfer mechanism of bacteria within an electroactive biofilm was investigated by using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). First, a mature anodic electroactive biofilm was developed from an activated sludge sample (inoculum), acetate as electron donor and a poised electrode (+397. mV vs. SHE). Later, this biofilm was "switched" to biocathodic conditions by feeding it with a medium containing nitrates and poising the electrode at -303. mV vs. SHE. The electrochemical characterization indicated that both, acetate oxidation and nitrate reduction took place at a similar formal potential of -175±05 and -175±34. mV vs. SHE, respectively. The biofilm was predominantly composed by Geobacter sp. at both experimental conditions. Taken together, the results indicated that both processes could be catalyzed by using the same electron conduit, and most likely by the same bacterial consortium. Hence, this study suggests that electroactive bacteria within biofilms could use the same electron transfer conduit for catalyzing anodic and cathodic reaction

This work was supported by the Spanish Government (CTQ2014 SGR-1168,CTQ2014-53718-R). A.A.C.M.was supported by the French National Research Agency (Project:ANR‐10‐BTBR‐02). N.P. was supported by the Catalan Government (2012FI B00941). The authors acknowledge the scientific contribution of Pau Batlle-Vilanova (LEQUIA-UdG)

Elsevier

Manager: Ministerio de Economía y Competitividad (Espanya)
Generalitat de Catalunya. Agència de Gestió d’Ajuts Universitaris i de Recerca
Author: Pous Rodríguez, Narcís
Carmona Martínez, Alessandro A.
Vilajeliu Pons, Anna
Fiset, Erika
Bañeras Vives, Lluís
Trably, Eric
Balaguer i Condom, Maria Dolors
Colprim Galceran, Jesús
Bernet, Nicolas
Puig Broch, Sebastià
Abstract: Up to date a few electroactive bacteria embedded in biofilms are described to catalyze both anodic and cathodic reactions in bioelectrochemical systems (i.e. bidirectional electron transfer). How these bacteria transfer electrons to or from the electrode is still uncertain. In this study the extracellular electron transfer mechanism of bacteria within an electroactive biofilm was investigated by using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). First, a mature anodic electroactive biofilm was developed from an activated sludge sample (inoculum), acetate as electron donor and a poised electrode (+397. mV vs. SHE). Later, this biofilm was "switched" to biocathodic conditions by feeding it with a medium containing nitrates and poising the electrode at -303. mV vs. SHE. The electrochemical characterization indicated that both, acetate oxidation and nitrate reduction took place at a similar formal potential of -175±05 and -175±34. mV vs. SHE, respectively. The biofilm was predominantly composed by Geobacter sp. at both experimental conditions. Taken together, the results indicated that both processes could be catalyzed by using the same electron conduit, and most likely by the same bacterial consortium. Hence, this study suggests that electroactive bacteria within biofilms could use the same electron transfer conduit for catalyzing anodic and cathodic reaction
This work was supported by the Spanish Government (CTQ2014 SGR-1168,CTQ2014-53718-R). A.A.C.M.was supported by the French National Research Agency (Project:ANR‐10‐BTBR‐02). N.P. was supported by the Catalan Government (2012FI B00941). The authors acknowledge the scientific contribution of Pau Batlle-Vilanova (LEQUIA-UdG)
Format: application/pdf
Document access: http://hdl.handle.net/10256/13144
Language: eng
Publisher: Elsevier
Collection: info:eu-repo/semantics/altIdentifier/doi/10.1016/j.bios.2015.08.035
info:eu-repo/semantics/altIdentifier/issn/0956-5663
info:eu-repo/grantAgreement/MINECO//CTQ2014-53718-R/ES/TECNOLOGIAS INNOVADORAS PARA LA MEJORA DE BIOGAS: DESDE LA INVESTIGACION BASICA A LA EVALUACION DE TECNOLOGIAS/
AGAUR/2014-2016/2014 SGR 1168
Rights: Tots els drets reservats
Subject: Bioelectroquímica
Bioelectrochemistry
Bioremediació
Bioremediation
Nitrats
Nitrates
Title: Bidirectional microbial electron transfer: Switching an acetate oxidizing biofilm to nitrate reducing conditions
Type: info:eu-repo/semantics/article
Repository: DUGiDocs

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