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

Bin Zhao; Dan Yang Cheng; Pan Tan; Qiang An; Jin Song Guo

doi:10.1016/j.biortech.2017.11.038

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

Bioresour Technol. 2018 Feb:250:564-573. doi: 10.1016/j.biortech.2017.11.038. Epub 2017 Nov 14.

Authors

Bin Zhao¹, Dan Yang Cheng², Pan Tan², Qiang An³, Jin Song Guo¹

Affiliations

¹ Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, PR China; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400045, PR China.
² Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, PR China.
³ Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, PR China; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400045, PR China. Electronic address: anqiang@cqu.edu.cn.

PMID: 29197780
DOI: 10.1016/j.biortech.2017.11.038

Abstract

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.

Keywords: Aerobic denitrification; Denitrification genes; NapA; NirS; Nitrate removal.

MeSH terms

Aerobiosis
Denitrification*
Nitrates
Nitrogen
Pseudomonas stutzeri*

Substances

Nitrates
Nitrogen