Multiple pathways of vanadate reduction and denitrification mediated by denitrifying bacterium Acidovorax sp. strain BoFeN1

Yangmei Fei; Baogang Zhang; Qinghao Zhang; Dandan Chen; Wengeng Cao; Alistair G L Borthwick

doi:10.1016/j.watres.2024.121747

Multiple pathways of vanadate reduction and denitrification mediated by denitrifying bacterium Acidovorax sp. strain BoFeN1

Water Res. 2024 May 7:257:121747. doi: 10.1016/j.watres.2024.121747. Online ahead of print.

Authors

Yangmei Fei¹, Baogang Zhang², Qinghao Zhang¹, Dandan Chen³, Wengeng Cao⁴, Alistair G L Borthwick⁵

Affiliations

¹ MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, School of Water Resources and Environment, China University of Geosciences Beijing, Beijing 100083, PR China.
² MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, School of Water Resources and Environment, China University of Geosciences Beijing, Beijing 100083, PR China. Electronic address: baogangzhang@cugb.edu.cn.
³ School of Biological and Chemical Engineering, Panzhihua University, Panzhihua 617000, PR China.
⁴ The Institute of Hydrogeology and Environmental Geology, Chinese Academy of Geological Science (CAGS), Key Laboratory of Groundwater Remediation of Hebei Province and China Geological Survey, Shijiazhuang 050061, PR China.
⁵ St Edmund Hall, Queen's Lane, Oxford OX1 4AR, UK; School of Engineering, The University of Edinburgh, The King's Buildings, Edinburgh EH9 3JL, UK; School of Engineering, Computing and Mathematics, University of Plymouth, Drakes Circus, Plymouth PL4 8AA, UK.

PMID: 38733964
DOI: 10.1016/j.watres.2024.121747

Abstract

Contamination of aquifers by a combination of vanadate [V(V)] and nitrate (NO₃^-) is widespread nowadays. Although bioremediation of V(V)- and nitrate-contaminated environments is possible, only a limited number of functional species have been identified to date. The present study demonstrates the effectiveness of V(V) reduction and denitrification by a denitrifying bacterium Acidovorax sp. strain BoFeN1. The V(V) removal efficiency was 76.5 ± 5.41 % during 120 h incubation, with complete removal of NO₃^- within 48 h. Inhibitor experiments confirmed the involvement of electron transport substances and denitrifying enzymes in the bioreduction of V(V) and NO₃^-. Cyt c and riboflavin were important for extracellular V(V) reduction, with quinone and EPS more significant for NO₃^- removal. Intracellular reductive compounds including glutathione and NADH directly reduce V(V) and NO₃^-. Reverse transcription quantitative PCR confirmed the important roles of nirK and napA genes in regulating V(V) reduction and denitrification. Bioaugmentation by strain BoFeN1 increased V(V) and NO₃^- removal efficiency by 55.3 % ± 2.78 % and 42.1 % ± 1.04 % for samples from a contaminated aquifer. This study proposes new microbial resources for the bioremediation of V(V) and NO₃^-contaminated aquifers, and contributes to our understanding of coupled vanadium, nitrogen, and carbon biogeochemical processes.

Keywords: Bioremediation; Denitrifying bacteria; Groundwater; Nitrate; Vanadium.