Nitrate Reduction with Halomonas campisalis: Kinetics of Denitrification at pH 9 and 12.5% NaCl


Regeneration of ion exchange resins with NaCl produces brine containing high concentrations of nitrate that can be difficult to remove using standard biological, physical, or chemical technologies. In this study, Halomonas campisalis (ATCC #700597) (Mormile et al., 1999) was shown to completely reduce nitrate at 125 g/L NaCl and pH 9. This organism was also used in experiments to determine nitrate-reduction rates and biomass yields. Kinetic parameters were measured separately with glycerol, lactate, acetate, ethanol, and methanol. The specific nitrate-reduction rate coefficient was highest in cultures amended with acetate, while lactate and glycerol (a natural osmoticum in hypersaline environments) had lower reduction rates. No evidence of nitrate reduction was observed when ethanol or methanol was provided as an electron donor. Kinetic modeling provided values for nitrate and nitrite-reduction rate coefficients and for biomass yields. Measured rates and yields were similar to reported parameters obtained from non-halophilic nitrate-reducing cultures under low salt concentrations. Therefore, for highly saline solutions, the use of halophiles to selectively remove nitrate from these brines may represent a viable treatment option.


Biological Sciences


Pacific Northwest National Laboratory (U.S.). Microbial Biotechnology Initiative


We thank Ray Wildung and the support of the Microbial Biotechnology Initiative at Pacific Northwest National Laboratory.

Keywords and Phrases

Alcohols; Biomass; Enzymes; Glycerol; Nitrates; Saline Water; Sodium Chloride; Kinetic Modeling; Resins; Acetic Acid; Lactic Acid; Methanol; Nitrite; Alkaline Medium; Brine; Denitrification; Ion Exchange; Kinetics; Reduction; Reverse Osmosis; Bacterial Growth; Concentration Response; Denitrification; Electron; Halomonas; Halophilic Bacterium; Mathematical Analysis; Measurement; Nonhuman; pH; Hydrogen-Ion Concentration; Ion Exchange Resins; Osmosis; Waste Disposal, Fluid

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Article - Journal

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© 2001 Elsevier, All rights reserved.

Publication Date

01 Dec 2001

PubMed ID