Enhancement of nitrite production via addition of hydroxylamine to partial denitrification (PD) biomass: Functional genes dynamics and enzymatic activities

Xingxing Zhang; Yunkang Xia; Chaochao Wang; Jiajia Li; Peng Wu; Liping Ma; Yuguang Wang; Yao Wang; Fanghua Da; Wenru Liu; Lezhong Xu

doi:10.1016/j.biortech.2020.124274

Enhancement of nitrite production via addition of hydroxylamine to partial denitrification (PD) biomass: Functional genes dynamics and enzymatic activities

Bioresour Technol. 2020 Dec:318:124274. doi: 10.1016/j.biortech.2020.124274. Epub 2020 Oct 17.

Authors

Xingxing Zhang¹, Yunkang Xia¹, Chaochao Wang¹, Jiajia Li¹, Peng Wu², Liping Ma³, Yuguang Wang¹, Yao Wang¹, Fanghua Da¹, Wenru Liu⁴, Lezhong Xu⁴

Affiliations

¹ School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou, China.
² School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou, China; National and Local Joint Engineering Laboratory of Municipal Sewage Resource Utilization Technology, No. 1 Kerui Road, Suzhou, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, No. 1 Kerui Road, Suzhou, China. Electronic address: wupengniu@126.com.
³ Shanghai Key Laboratory for Urban Ecological Processes and Eco-Restoration, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China.
⁴ School of Environmental Science and Engineering, Suzhou University of Science and Technology, No. 1 Kerui Road, Suzhou, China; National and Local Joint Engineering Laboratory of Municipal Sewage Resource Utilization Technology, No. 1 Kerui Road, Suzhou, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, No. 1 Kerui Road, Suzhou, China.

PMID: 33096441
DOI: 10.1016/j.biortech.2020.124274

Abstract

This study investigated the activity of partial denitrification (PD) biomass/key enzymes, functional gene expressions in response to 0 ~ 50 mg/L hydroxylamine (NH₂OH) addition. Results indicated that NH₂OH contributed to nitrite (NO₂^--N) production, facilitating the maximum increase of nitrate (NO₃^--N) to NO₂^--N transformation ratio to 80.47 ± 2.82%, leading to 2.56-fold NO₂^--N higher than those of control. The observed transient inhibitory effect on NO₃^--N reduction process was attributed by high-level NH₂OH (35 ~ 50 mg/L). Enzymatic assays revealed the enhanced activity of both NO₃^--N and NO₂^--N reductase while the former showed obvious superiority which led to high NO₂^--N accumulation. These results were further confirmed by the corresponding functional genes (narG, napA, nirS and nirK). Besides, negative influence of NH₂OH addition was limited to PD aggregates, due to the increasing secretion of extracellular polymeric substances (EPS) as well as proteins/polysaccharides ratios in tightly-bound structure of EPS.

Keywords: Enzymatic activities; Extracellular polymeric substances (EPS); Functional genes; Hydroxylamine (NH(2)OH) exposure; Partial denitrification (PD).

MeSH terms

Biomass
Denitrification*
Hydroxylamine
Hydroxylamines
Nitrites*
Nitrogen

Substances

Hydroxylamines
Nitrites
Hydroxylamine
Nitrogen