Simultaneous removal of nitrogen and phosphorus by a novel aerobic denitrifying phosphorus-accumulating bacterium, Pseudomonas stutzeri ADP-19

A novel denitrifying phosphorus-accumulating bacterium was isolated from contaminated sediment and identified as Pseudomonas stutzeri ADP-19. Bio-safety assays demonstrated that the strain was gamma-hemolytic, antibiotic-sensitive, and had no decarboxylase activity. It removed 96.5% of NH4+-N and 73.3% of PO43--P (at initial concentrations of 100 mg/L and 20 mg/L) under aerobic conditions, and the corresponding maximum removal rates were 3.44 and 0.41 mg/L/h, respectively. Nitrogen removal was achieved through a fully nitrification-denitrification pathway [NH4+-N -> NH2OH -> NO2--N -> NO3--N -> NO2--N -> (NxO) -> N-2], while phosphorus removal mainly depended on the phosphate assimilation and the excessive poly-P accumulation. Strain ADP-19 also showed a strong salt tolerance within a wide salinity range of 0-5%. The enhanced biological treatment of anaerobic-digested wastewater in a sequencing batch reactor (SBR) indicated that the strain improved the microbial diversity of the activated sludge and significantly enhanced the nitrogen and phosphorus removal efficiency.

Automated summary

The novel denitrifying phosphorus-accumulating bacterium isolated from contaminated sediment is identified as Pseudomonas stutzeri ADP-19, showing strong capabilities in nitrogen and phosphorus removal under aerobic conditions. Additionally, the bacterium demonstrated strong salt tolerance and improved microbial diversity in the biological treatment of anaerobic-digested wastewater, enhancing nitrogen and phosphorus removal efficiency significantly.