Response of nitrite accumulation to elevated C/NO- 3-N ratio during partial denitrification process: Insights of extracellular polymeric substance, microbial community and metabolic function

Zilong Hou; Wenyi Dong; Hongjie Wang; Zilong Zhao; Zhuoyang Li; Huaguang Liu; Yanchen Li; Zhiwei Zeng; Jin Xie; Liang Zhang; Jie Liu

doi:10.1016/j.biortech.2023.129269

Response of nitrite accumulation to elevated C/NO- 3-N ratio during partial denitrification process: Insights of extracellular polymeric substance, microbial community and metabolic function

Bioresour Technol. 2023 Sep:384:129269. doi: 10.1016/j.biortech.2023.129269. Epub 2023 Jun 7.

Authors

Zilong Hou¹, Wenyi Dong², Hongjie Wang², Zilong Zhao³, Zhuoyang Li¹, Huaguang Liu¹, Yanchen Li¹, Zhiwei Zeng¹, Jin Xie¹, Liang Zhang⁴, Jie Liu⁴

Affiliations

¹ School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, China.
² School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, China; Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control, Shenzhen 518055, China; State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin 150090, China.
³ School of Civil and Environmental Engineering, Harbin Institute of Technology Shenzhen, Shenzhen 518055, China; Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control, Shenzhen 518055, China. Electronic address: berthillon@hotmail.com.
⁴ Shenzhen Wanmu Water Services Co., Shenzhen 518000, China.

PMID: 37290706
DOI: 10.1016/j.biortech.2023.129269

Abstract

This study investigated the response of nitrite accumulation to elevated COD/NO₃^--N ratio (C/N) during partial denitrification (PD). Results indicated nitrite was gradually accumulated and remained stable (C/N = 1.5 ∼ 3.0), while that rapidly declined after reaching the peak (C/N = 4.0 ∼ 5.0). The polysaccharide (PS) and protein (PN) content of tightly-bound extracellular polymeric substances (TB-EPS) reached the maximum at C/N of 2.5 ∼ 3.0, which might be stimulated by high level of nitrite. Illumina MiSeq sequencing showed Thauera and OLB8 were dominated denitrifying genera at C/N of 1.5 ∼ 3.0, while Thauera was further enriched with fading OLB8 at C/N of 4.0 ∼ 5.0. Meanwhile, the highly-enriched Thauera might enhance the activity of nitrite reductase (nirK) promoting further nitrite reduction. Redundancy analysis (RDA) showed positive correlations between nitrite production and PN content of TB-EPS, denitrifying bacteria (Thauera and OLB8) and nitrate reductases (narG/H/I) in low C/N. Finally, their synergistic effects for driving nitrite accumulation were comprehensively elucidated.

Keywords: COD/NO(3)(–)-N ratio; Nitrite accumulation; Nitrite reductase; OLB8 genus; Redundancy analysis.

MeSH terms

Denitrification
Extracellular Polymeric Substance Matrix / metabolism
Microbiota*
Nitrites* / metabolism
Nitrogen / metabolism
Thauera / metabolism

Substances

Nitrites
Nitrogen