Isolation And Nitrogen Removal Characteristics Of A Heterotrophic Nitrification-Aerobic Denitrification Bacterium Pseudomonas Aeruginosa P-1

Ammonium is one of the major pollutants in wastewater,both of ammonium and its nitration products can do harm to the environment and animal health.Therefore,investigating the efficient and green method in ammonium removal would be significant in sewage treatment.Thus heterotrophic nitrification-aerobic denitrification bacteria have advantages in practical sewage treatment because of the directly transformation of ammonium to nitrogen gas.In this article,a heterotrophic nitrification-aerobic denitrification bacterium was isolated,and it was identified as a gram-negative bacterium of Pseudomonas aeruginosa and named P-1.P-1 has the most powerful ability to remove ammonium in the three types nitrogen compounds ions of ammonium,nitrite and nitrate.When these three types ions were co-exist,P-1 preferentially nitrified NH4⁺to NO3^-,and only began to denitrify NO₂^-and NO₃^-when the NH₄⁺had been almost entirely depleted.Besides,P-1 has the strong tolerance ability of NaCl?0-50 mg/L?and some heavy metal ions?0-50 mg/L?as Cu²⁺,Zn²⁺,Cr⁶⁺,Pb²⁺,and Cd²⁺.There was almostly no nitrite accumulation in the whole process of HN-AD.The enzyme activities of AMO,HAO,NAR and NIR of strain P-1 were detected,and the activity of AMO was much higher than other three enzymes.The final gaseous product was N2 in the nitrogen removal functions of NH4⁺,NO3^-and NO2^-.And we conjectured that P-1 could exert in both complete HN-AD pathway which included the transformation of nitrite and nitrate and the short HN-AD pathway in which NH₂OH was converted to nitrogenous gas directly,and the exact pathway was determined by the type of inorganic nitrogen in the water.Given the above,this article enriches the theory of HN-AD,and provides an alternative bacterium in wastewater treatment in practice.