Ammonium removal at low temperature by a newly isolated heterotrophic nitrifying and aerobic denitrifying bacterium Pseudomonas fluorescens wsw-1001

Abstract

A heterotrophic nitrifier wsw-1001 was isolated from Songhua River and identified as Pseudomonas fluorescens. Ammonium removal by the strain at low temperature was investigated. The effect of initial ammonium concentration (from 5 to 1000 mg/L) and culture temperature (from 4°C to 30°C) on ammonium removal efficiency was studied. Biodegradation product, , , N₂, N₂O and intercellular N were monitored. The results indicated that the strain had potential for water and wastewater treatment. Ammonium could be removed by the strain at low temperature. Ammonium removal efficiency increased with temperature from 4°C to 20°C and decreased with ammonium concentration from 5 to 1000 mg/L. The strain exhibited a capability of heterotrophic nitrification and aerobic denitrification using as the sole nitrogen source at 8°C. and were reduced by the strain. Nitrogen balance analysis in the presence of 39.7 mg/L indicated that 71.2% was removed by converting to N₂ (46.3%) and assimilating as biomass (42.5%). Substances such as , and N₂O were detected at very low concentrations. Ammonium mono-oxygenase, hydroxylamine oxidase, nitrite reductase and nitrate reductase activity were measured. The ammonium removal pathway of the strain was speculated to be .

Keywords:

• ammonium removal
• Pseudomonas fluorescens
• heterotrophic nitrification
• aerobic denitrification
• low temperature

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [grant number 51078106[, Science and Technology Department of Heilongjiang Province [grant number GA13C302] and Finance Department of Heilongjiang Province (grant number CZ12BZSM06).