Heterotrophic denitrification at extremely high salt and pH by haloalkaliphilic Gammaproteobacteria from hypersaline soda lakes

Winogradsky Institute of Microbiology, Russian Academy of Sciences, Prospect 60-let Octyabrya 7/2, 117811 Moscow, Russia.
Extremophiles (Impact Factor: 2.31). 06/2008; 12(5):619-25. DOI: 10.1007/s00792-008-0166-6
Source: PubMed


In this paper we describe denitrification at extremely high salt and pH in sediments from hypersaline alkaline soda lakes and soda soils. Experiments with sediment slurries demonstrated the presence of acetate-utilizing denitrifying populations active at in situ conditions. Anaerobic enrichment cultures at pH 10 and 4 M total Na+ with acetate as electron donor and nitrate, nitrite and N2O as electron acceptors resulted in the dominance of Gammaproteobacteria belonging to the genus Halomonas. Both mixed and pure culture studies identified nitrite and N2O reduction as rate-limiting steps in the denitrification process at extremely haloalkaline conditions.

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    • "It is unfortunate that all these reported halophilic species only grew and actively denitrified under aerobic conditions. Because of the low concentrations of dissolved oxygen in industrial wastewaters, these reported aerobic halophilic species were not suitable for application in treatment of industrial wastewater (Shapovalova et al., 2008). The objective of this research was to isolate and characterize new halophilic denitrifying bacteria with better potential for saline industrial wastewater treatment . "
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    • "This is reflected by the existence of partial denitrifiers with more or less severely truncated reduction pathways (e.g. Sorokin et al., 2003; Simon et al., 2004; Shapovalova et al., 2008; Falk et al., 2010). A significant fraction of cultured denitrifiers lacks a nosZ gene coding for N 2 O reductase (Jones et al., 2008). "
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