[Biological characteristics of denitrifying polyphosphate-accumulating organisms]

A denitrifying phosphate-accumulating organisms (DNPAOs), which was called Q-hrb05, was isolated in the special medium from the anaerobic/aerobic/anoxic SBR reactor. Strain Q-hrb05 was identified by 16SrDNA gene analysis, and the accession number of 16SrDNA gene sequence of strain Q-hrb05 in GenBank was GU214826. Effects of the different pH values, temperature, carbon source of medium on nitrogen and phosphorus removal of strain Q-hrb05 were investigated. The result showed that strain Q-hrb05 belonged to Bacillus sp.. Meanwhile, extracellular exopolymers of strain Q-hrb05 was based on protein, about 120.6 mg x mL(-1), and it had 23.05 microg x mL(-1) nucleic acid, but little polysaccharide. There was no significant adsorption of phosphate. So phosphorus removal was mainly due to intracellular uptake. And when pH value was kept as 7, temperature was kept as 30 degrees C, and carbon source was kept sodium acetate, the highest nitrogen and phosphorus removal efficiency was achieved. Phosphorus uptake rate was averaged at 88%, and the denitrification rate reached 81%.