Isolation and characterization of denitrifying bacterium Pseudomonas mendocina aHD7 with anaerobic ammonium oxidization

摘要

A denitrifying bacterium aHD7 with nitrate removal efficiency of 91.67% (w/w) in 3days cultured at 30°C under stationary conditions was isolated from the activated sludge. The strain was characterized by biochemical tests and 16S rDNA sequence analysis, to be belonging to Pseudomonas. Factors on denitrification ability of aHD7, i.e., pH value, carbon source, C/N ratio, nitrogen source and initial nitrate concentration were investigated. Results showed that this strain could either use nitrate or nitrite as the electron acceptor, and the total inorganic nitrogen removal efficiency for sodium nitrite and potassium nitrate were up to 96.70% (w/w) and 95.93% (w/w) respectively. Denitrification was favored when the pH value was 6-9 and C/N ratio varied from 6 to 8, in which the optimal carbon source was ethanol. The strain had anammox activity, of which the average ammonium utilization rate reached up to 4.56 mg/l/d.