Characterization of an aerobic denitrifier Pseudomonas stutzeri strain XL-2 to achieve efficient nitrate removal

• Published in: Bioresource technology Vol. 250; pp. 564 - 573
• Main Authors: Zhao, Bin, Cheng, Dan Yang, Tan, Pan, An, Qiang, Guo, Jin Song
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.02.2018
• Subjects: Aerobic denitrification; Aerobiosis; biochemical pathways; Denitrification; Denitrification genes; denitrifying microorganisms; dissolved oxygen; NapA; NirS; Nitrate removal; Nitrates; Nitrogen; nitrogen balance; Pseudomonas stutzeri; technology; temperature; Nitrate removal; NapA; NirS; Denitrification genes; Aerobic denitrification
• ISSN: 0960-8524; 1873-2976; 1873-2976
• DOI: 10.1016/j.biortech.2017.11.038

•An aerobic denitrifier, P. stutzeri XL-2, was newly isolated.•Strain XL-2 presents great capability to reduce nitrate aerobically.•The production of N2 was much greater than N2O by strain XL-2.•The optimal conditions for nitrate removal were investigated.•Denitrification genes of napA, nirS, norB and nosZ were successfully amplified. An aerobic denitrifier was newly isolated and identified as Pseudomonas stutzeri strain XL-2. Strain XL-2 removed 97.9% of nitrate with an initial concentration about 100 mg/L. Nitrogen balance indicates that 12.4% of the initial nitrogen was converted to N2O, and 62.4% was converted to N2. Single factor experiments indicate that the optimal conditions for nitrate removal were C/N ratio of 10, temperature of 30 °C and shaking speed of 120 rpm. Sequence amplification indicates that the denitrification genes of napA, nirS, norB and nosZ were present in strain XL-2. Combined with nitrogen balance, strain XL-2 presents the metabolic pathway of NO3− → NO2− → NO  →  N2O → N2 under aerobic conditions. The expression of napA and nirS might be responsible for the tolerance of dissolved oxygen by strain XL-2 during denitrification process.