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Denitrifying Bacterial Communities Affect Current Production and Nitrous Oxide Accumulation in a Microbial Fuel Cell

The biocathodic reduction of nitrate in Microbial Fuel Cells (MFCs) is an alternative to remove nitrogen in low carbon to nitrogen wastewater and relies entirely on microbial activity. In this paper the community composition of denitrifiers in the cathode of a MFC is analysed in relation to added electron acceptors (nitrate and nitrite) and organic matter in the cathode. Nitrate reducers and nitrite reducers were highly affected by the operational conditions and displayed high diversity. The number of retrieved species-level Operational Taxonomic Units (OTUs) for narG, napA, nirS and nirK genes was 11, 10, 31 and 22, respectively. In contrast, nitrous oxide reducers remained virtually unchanged at all conditions. About 90% of the retrieved nosZ sequences grouped in a single OTU with a high similarity with Oligotropha carboxidovorans nosZ gene. nirS-containing denitrifiers were dominant at all conditions and accounted for a significant amount of the total bacterial density. Current production decreased from 15.0 A·m−3 NCC (Net Cathodic Compartment), when nitrate was used as an electron acceptor, to 14.1 A·m−3 NCC in the case of nitrite. Contrarily, nitrous oxide (N2O) accumulation in the MFC was higher when nitrite was used as the main electron acceptor and accounted for 70% of gaseous nitrogen. Relative abundance of nitrite to nitrous oxide reducers, calculated as (qnirS+qnirK)/qnosZ, correlated positively with N2O emissions. Collectively, data indicate that bacteria catalysing the initial denitrification steps in a MFC are highly influenced by main electron acceptors and have a major influence on current production and N2O accumulation

A. V-S. and A. G-L. are recipients of pre-doctoral grants from the Universitat de Girona and the Ministerio de Ciencia y Educacion, respectively. This research was funded through grants from the Spanish Government (CGL2009-08338, CSD2007-00055 and CTQ2011-23632)

PLoS ONE, 2013, vol. 8, núm. 5, p. e63460

Public Library of Science

Author: Vilar Sanz, Ariadna
Puig Broch, Sebastià
García Lledó, Arantzazu
Trias Mansilla, Rosalia
Balaguer i Condom, Maria Dolors
Colprim Galceran, Jesús
Bañeras Vives, Lluís
Date: 2013
Abstract: The biocathodic reduction of nitrate in Microbial Fuel Cells (MFCs) is an alternative to remove nitrogen in low carbon to nitrogen wastewater and relies entirely on microbial activity. In this paper the community composition of denitrifiers in the cathode of a MFC is analysed in relation to added electron acceptors (nitrate and nitrite) and organic matter in the cathode. Nitrate reducers and nitrite reducers were highly affected by the operational conditions and displayed high diversity. The number of retrieved species-level Operational Taxonomic Units (OTUs) for narG, napA, nirS and nirK genes was 11, 10, 31 and 22, respectively. In contrast, nitrous oxide reducers remained virtually unchanged at all conditions. About 90% of the retrieved nosZ sequences grouped in a single OTU with a high similarity with Oligotropha carboxidovorans nosZ gene. nirS-containing denitrifiers were dominant at all conditions and accounted for a significant amount of the total bacterial density. Current production decreased from 15.0 A·m−3 NCC (Net Cathodic Compartment), when nitrate was used as an electron acceptor, to 14.1 A·m−3 NCC in the case of nitrite. Contrarily, nitrous oxide (N2O) accumulation in the MFC was higher when nitrite was used as the main electron acceptor and accounted for 70% of gaseous nitrogen. Relative abundance of nitrite to nitrous oxide reducers, calculated as (qnirS+qnirK)/qnosZ, correlated positively with N2O emissions. Collectively, data indicate that bacteria catalysing the initial denitrification steps in a MFC are highly influenced by main electron acceptors and have a major influence on current production and N2O accumulation
A. V-S. and A. G-L. are recipients of pre-doctoral grants from the Universitat de Girona and the Ministerio de Ciencia y Educacion, respectively. This research was funded through grants from the Spanish Government (CGL2009-08338, CSD2007-00055 and CTQ2011-23632)
Format: application/pdf
ISSN: 1932-6203
Document access: http://hdl.handle.net/10256/8592
Language: eng
Publisher: Public Library of Science
Collection: MICINN/PN 2010-2012/CGL2009-08338
MEC/PN 2007-2013/CSD2007-00055
MICINN/PN 2012-2014/CTQ2011-23632
Reproducció digital del document publicat a: http://dx.doi.org/10.1371/journal.pone.0063460
Articles publicats (D-EQATA)
Is part of: PLoS ONE, 2013, vol. 8, núm. 5, p. e63460
Rights: Attribution 3.0 Spain
Rights URI: http://creativecommons.org/licenses/by/3.0/es/
Subject: Càtodes
Cathodes
Reducció química
Reduction (Chemistry)
Nitrats
Nitrates
Aigües residuals -- Depuració -- Desnitrificació
Sewage -- Purification -- Nitrogen removal
Title: Denitrifying Bacterial Communities Affect Current Production and Nitrous Oxide Accumulation in a Microbial Fuel Cell
Type: info:eu-repo/semantics/article
Repository: DUGiDocs

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