The role of anthraquinone-2-sulfonate on intra/extracellular electron transfer of anaerobic nitrate reduction

Lei Yu; Cheng-Jia Ju; Kai-Yan Jing; Zi-Yang Wang; Shareen Niyazi; Quan Wang

doi:10.1016/j.jenvman.2023.117455

The role of anthraquinone-2-sulfonate on intra/extracellular electron transfer of anaerobic nitrate reduction

J Environ Manage. 2023 May 1:333:117455. doi: 10.1016/j.jenvman.2023.117455. Epub 2023 Feb 7.

Authors

Lei Yu¹, Cheng-Jia Ju², Kai-Yan Jing³, Zi-Yang Wang⁴, Shareen Niyazi², Quan Wang⁵

Affiliations

¹ Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037, China; College of Biology and the Environment, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, China.
² Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037, China.
³ College of Ecology and Environmental Sciences, East China Normal University, Shanghai, 200241, China.
⁴ Soil Environment Research Institute, Jiangsu Provincial Academy of Environmental Science, 210003, Nanjing, China.
⁵ Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing, 210037, China; College of Biology and the Environment, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, 210037, China. Electronic address: wangquan021@njfu.edu.cn.

PMID: 36758409
DOI: 10.1016/j.jenvman.2023.117455

Abstract

To improve the electron (e^-) transfer efficiency, exogenous redox mediators (RMs) were usually employed to enhance the denitrification efficiency due to the electron shuttling. Previous studies were mainly focused on how to improve the extracellular electron transfer (EET) by exogenous RMs. However, the intracellular electron transfer (IET), another crucial e^- transfer pathway, of biological denitrification was scarcely reported, especially for the relationship between the denitrification and IET. In this study, Coenzyme Q, Complexes I, II and III were determined as the core components in the IET chain of denitrification by using four specific respiration chain inhibitors (RCIs). Anthraquinone-2-sulfonate (AQS) partially recovered the IET of denitrification from NO₃^--N to N₂ gas when the RCIs were added. Specifically, the generations of N₂ gas were improved by 9.68%-18.25% in the experiments with RCIs and AQS, comparing to that with RCIs. nrfA gene was not detected by reverse transcription-polymerase chain reaction, suggesting that Klebsiella oxytoca strain could not conduct dissimilatory nitrate reduction to ammonium. Nitrate assimilation was considered as the main NH₄⁺-N formation way of K. oxytoca strain. The two e^- transfer pathways of denitrification were constructed and the roles of AQS on the IET and EET of denitrification were specifically discussed. The results of this study provided a better understanding of the e^- transfer pathways of denitrification, and suggested a potential practical use of exogenous RM on bio-treatment of nitrate-containing wastewater.

Keywords: Anaerobic denitrification; Biohydrogen production; Extracellular electron transfer; Intracellular electron transfer; Redox mediator.

MeSH terms

Ammonium Compounds* / metabolism
Anaerobiosis
Denitrification
Electrons
Nitrates* / analysis
Nitrogen
Oxidation-Reduction

Substances

Nitrates
Ammonium Compounds
Nitrogen