Role of the denitrifying Haloarchaea in the treatment of nitrite-brines

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Title: Role of the denitrifying Haloarchaea in the treatment of nitrite-brines
Authors: Nájera Fernández, Cindy | Zafrilla Requena, Basilio | Bonete, María-José | Martínez-Espinosa, Rosa María
Research Group/s: Biotecnología de Extremófilos (BIOTECEXTREM)
Center, Department or Service: Universidad de Alicante. Departamento de Agroquímica y Bioquímica
Keywords: Haloferax mediterranei | Haloarchaea | Respiratory nitrite pathway | Assimilatory nitrite pathway | Brines | Denitrification | Bioremediation
Knowledge Area: Bioquímica y Biología Molecular
Issue Date: 2012
Publisher: Spanish Society for Microbiology (SEM)
Citation: NÁJERA-FERNÁNDEZ, Cindy, et al. “Role of the denitrifying Haloarchaea in the treatment of nitrite-brines”. International Microbiology. Vol. 15, No. 3 (2012). ISSN 1139-6709, pp. 111-119
Abstract: Haloferax mediterranei is a denitrifying halophilic archaeon able to reduce nitrate and nitrite under oxic and anoxic conditions. In the presence of oxygen, nitrate and nitrite are used as nitrogen sources for growth. Under oxygen scarcity,this haloarchaeon uses both ions as electron acceptors via a denitrification pathway. In the present work, the maximal nitriteconcentration tolerated by this organism was determined by studying the growth of H. mediterranei in minimal medium containing30, 40 and 50 mM nitrite as sole nitrogen source and under initial oxic conditions at 42 °C. The results showed theability of H. mediterranei to withstand nitrite concentrations up to 50 mM. At the beginning of the incubation, nitrate wasdetected in the medium, probably due to the spontaneous oxidation of nitrite under the initial oxic conditions. The completeremoval of nitrite and nitrate was accomplished in most of the tested conditions, except in culture medium containing 50 mMnitrite, suggesting that this concentration compromised the denitrification capacity of the cells. Nitrite and nitrate reductases activities were analyzed at different growth stages of H. mediterranei. In all cases, the activities of the respiratory enzymeswere higher than their assimilative counterparts; this was especially the case for NirK. The denitrifying and possibly detoxifyingrole of this enzyme might explain the high nitrite tolerance of H. mediterranei. This archaeon was also able to remove60 % of the nitrate and 75 % of the nitrite initially present in brine samples collected from a wastewater treatment facility.These results suggest that H. mediterranei, and probably other halophilic denitrifying Archaea, are suitable candidates for thebioremediation of brines with high nitrite and nitrate concentrations.
Sponsor: This work was funded by research grants from the Spanish Ministry of Education and Science (BIO2008-00082), Generalitat Valenciana (GV/2011/038) and University of Alicante (GRE0925).
ISSN: 1139-6709 | 1618-1905 (Internet)
DOI: 10.2436/20.1501.01.164
Language: eng
Type: info:eu-repo/semantics/article
Rights: This work, including photographs and other illustrations, unless the contrary is indicated, is subject to an Attributions–Non-Commercial–ShareAlike 3.0 Creative Commons License, the full text of which can be consulted at You are free to share, copy, distribute and transmit the work provided that the author is credited and reuse of the material is restricted to non-commercial purposes only and that if you alter, transform, or build upon this work, you may distribute the resulting work only under the same or similar license to this one.
Peer Review: si
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Appears in Collections:INV - BIOTECEXTREM - Artículos de Revistas
INV - AppBiochem - Artículos de Revistas

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