Dissimilatory nitrate reduction to ammonium as an electron sink during cathodic denitrification

Sander, Elisa M., Virdis, Barnardino and Freguia, Stefano (2015) Dissimilatory nitrate reduction to ammonium as an electron sink during cathodic denitrification. RSC Advances, 5 105: 86572-86577. doi:10.1039/c5ra19241b

Author Sander, Elisa M.
Virdis, Barnardino
Freguia, Stefano
Title Dissimilatory nitrate reduction to ammonium as an electron sink during cathodic denitrification
Journal name RSC Advances   Check publisher's open access policy
ISSN 2046-2069
Publication date 2015
Year available 2015
Sub-type Article (original research)
DOI 10.1039/c5ra19241b
Open Access Status Not Open Access
Volume 5
Issue 105
Start page 86572
End page 86577
Total pages 6
Place of publication Cambridge, United Kingdom
Publisher Royal Society of Chemistry
Collection year 2016
Language eng
Formatted abstract
Dissimilatory nitrate reduction to ammonium (DNRA) is an undesired pathway occurring simultaneously to denitrification in natural environments as well as engineered systems aimed at biological nitrate reduction/removal. Ammonium formation has previously been detected in cathodic compartments of bioelectrochemical systems performing denitrification, although reported concentrations are generally very low. In order to demonstrate and quantify the occurrence of DNRA from nitrate in a mixed culture denitrifying cathodic biofilm, a carbon cloth working electrode was inoculated with a denitrifying microbial community and poised at −0.9 V vs. standard hydrogen electrode, while nitrate (20 mg L−1 NO3-N) was continuously fed at an HRT of 10 hours. Results showed that more than 40% of nitrogen added as nitrate was converted via DNRA when the biofilm was at initial stages of development. However, ammonium generation decreased to approximately 5% at later stages of development (7 months of operation), indicating that biofilm age plays a key role on biological pathways occurring during cathodic nitrate reduction. A closer insight revealed that the occurrence of DNRA is linked to cathodic coulombic efficiency: at low efficiency, a large fraction of the incoming electrons are converted to hydrogen or other reduced compounds within the biofilm, increasing the driving force for DNRA; at high coulombic efficiency, lower reducing power availability leads to nitrogen gas as preferred reduction product.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2016 Collection
Advanced Water Management Centre Publications
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