Abstract:[Background] At present, there is a lack of aerobic denitrification bacteria with significant nitrogen removal performance, high biological safety and alkali tolerance. Thus, it is difficult to treat high-alkaline industrial and aquaculture wastewater using biological methods. [Objective] The alkali-resistant and highly aerobic denitrification bacterium ZY-3 isolated from an aquaculture pond in Foshan city, Guangdong province was tested, in the hope of obtaining an efficient and safe aerobic denitrification bacterium which could be used in different pH environments for nitrogen removal. [Methods] The strain was identified by morphological observation, physiological and biochemical tests, and 16S rRNA gene sequence analysis. Antibiotic test and zebrafish challenge test were conducted to evaluate the environmental and biological safety of the strain. Three kinds of simulated wastewater containing different nitrogen levels were used to determine the nitrogen removal performance. [Results] ZY-3 was identified as Pseudomonas plecoglossicida, which was sensitive to a variety of clinically common antibiotics and had low aquatic toxicity. When this strain was cultivated in the three simulated wastewater with ammoniacal nitrogen, nitrite nitrogen or nitrate nitrogen as the sole nitrogen source at 28℃ and 180 r/min, the logarithmic phase appeared at 4−12 h. At 12 h, the removal rates of NH4+-N, NO3--N and NO2--N reached 94.87%, 81.44% and 98.02%, respectively. The pH tolerance range of the strain was 6.0−10.0. [Conclusion] A safe and efficient aerobic denitrification bacterium P. plecoglossicida ZY-3 was obtained, with a wide range of pH adaptation and rapid removal ability against three nitrogen sources (NH4+-N, NO3--N and NO2--N) under aerobic conditions.
