Characterisation of heterotrophic nitrifying and aerobic denitrifying Klebsiella pneumoniae CF-S9 strain for bioremediation of wastewater

Nitrogen pollution has been serious problem in environmental water particularly in freshwater ecosystems. A heterotrophic nitrifier and aerobic denitrifier was isolated and characterised from domestic wastewater. Based on phenotypic and phylogenetic characteristics, the isolate was identified as Klebsiella pneumonia. The strain had the capability to utilise ammonia, nitrate and nitrite as a sole nitrogen source. The maximum growth rate (mu(max)) of isolate was 0.55 h(-1) when ammonia used as nitrogen source. The isolate could express hydroxylamine oxidase (hao), periplasmic nitrate reductase (nap) and nitrite reductase (nir) which are essential for heterotrophic nitrification and aerobic denitrification. Both hao and napA genes were amplified in isolated strain by PCR. Furthermore, the isolate showed capacities of extracellular polymeric substances (EPS) secretion and auto-aggregation. Results demonstrated that the isolation of heterotrophic nitrifier and aerobic denitrifier favoured the bioremediation of nitrogenous compounds from domestic wastewater. (c) 2013 Elsevier Ltd. All rights reserved.