Intracellular electron competition in response to the oxygen pressure of the aerobic denitrification process in an O2-based membrane biofilm reactor (MBfR) for nitrate removal

Liang Feng; Fei-Yun Sun; Jixian Yang; Di Cui; Zuo-Hua Li; Shanshan Pi; He-Ping Zhao; Ang Li

doi:10.1016/j.scitotenv.2023.162592

Intracellular electron competition in response to the oxygen pressure of the aerobic denitrification process in an O₂-based membrane biofilm reactor (MBfR) for nitrate removal

Sci Total Environ. 2023 Jun 1:875:162592. doi: 10.1016/j.scitotenv.2023.162592. Epub 2023 Mar 6.

Authors

Liang Feng¹, Fei-Yun Sun¹, Jixian Yang², Di Cui³, Zuo-Hua Li⁴, Shanshan Pi¹, He-Ping Zhao⁵, Ang Li⁶

Affiliations

¹ State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China; Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control, Harbin Institute of Technology (Shenzhen), Guangdong 518055, PR China.
² State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China.
³ Engineering Research Center for Medicine, College of Pharmacy, Harbin University of Commerce, Harbin 150076, People's Republic of China.
⁴ Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control, Harbin Institute of Technology (Shenzhen), Guangdong 518055, PR China.
⁵ College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, People's Republic of China.
⁶ State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, People's Republic of China. Electronic address: li.ang@hit.edu.cn.

PMID: 36889408
DOI: 10.1016/j.scitotenv.2023.162592

Abstract

This study quantitatively investigated the effect of dissolved oxygen (DO) concentration on aerobic denitrification, and showed the mechanism of aerobic denitrification from the perspective of electron competition by cultivating Pseudomonas stutzeri T13, a typical aerobic denitrifier, in an oxygen-based membrane biofilm reactor (O₂-based MBfR). The experiments showed that when the O₂ pressure increased from 2 to 10 psig , the average effluent DO concentration during steady-state phases increased from 0.02 to 4.23 mg/L, and the corresponding mean NO₃^--N removal efficiency slightly decreased from 97.2 % to 90.9 %. Compared to the maximum theoretical flux of O₂ in various phases, the actual O₂ transfer flux increased from a limited status (2.07 e^- eq m^-2 d^-1 at 2 psig) to an excessive status (5.58 e^- eq m^-2 d^-1 at 10 psig). The increase of DO inhibited the electron availability for aerobic denitrification, which decreased from 23.97 % to 11.46 %, accompanying the increased electron availability for aerobic respiration from 15.87 % to 28.36 %. Unlike the napA and norB genes, the expression of the nirS and nosZ genes was significantly affected by DO, with the highest relative fold-changes of 6.5 and 6.13 at 4 psig O₂, respectively. The results contribute to clarifying the mechanism of aerobic denitrification from the quantitative perspective of electron distribution and the qualitative perspective of gene expression, which benefits the control and practical application of aerobic denitrification for wastewater treatment.

Keywords: Aerobic denitrification; Electron competition; Intracellular electron distribution; Oxygen-based membrane biofilm reactor; Pseudomonas stutzeri T13.

MeSH terms

Biofilms
Bioreactors
Denitrification*
Electrons
Nitrates*
Nitrogen
Oxygen

Substances

Nitrates
Oxygen
Nitrogen