Effects of magnetite on microbially driven nitrate reduction processes in groundwater

Yu Liu; Yuyu Wan; Zhe Ma; Weihong Dong; Xiaosi Su; Xiaofang Shen; Xiaokun Yi; Yaoxuan Chen

doi:10.1016/j.scitotenv.2022.158956

Effects of magnetite on microbially driven nitrate reduction processes in groundwater

Sci Total Environ. 2023 Jan 10:855:158956. doi: 10.1016/j.scitotenv.2022.158956. Epub 2022 Sep 21.

Authors

Yu Liu¹, Yuyu Wan², Zhe Ma², Weihong Dong³, Xiaosi Su², Xiaofang Shen¹, Xiaokun Yi¹, Yaoxuan Chen¹

Affiliations

¹ College of New Energy and Environment, Jilin University, Changchun, Jilin 130021, China; Institute of Water Resources and Environment, Jilin University, Changchun, Jilin 130021, China.
² Key Laboratory of Groundwater Resources and Environments, Ministry of Education, Jilin University, Changchun, Jilin 130021, China; Jilin Provincial Key Laboratory of Water Resources and Environment, Jilin University, Changchun, Jilin 130021, China.
³ Key Laboratory of Groundwater Resources and Environments, Ministry of Education, Jilin University, Changchun, Jilin 130021, China; Institute of Water Resources and Environment, Jilin University, Changchun, Jilin 130021, China; Jilin Provincial Key Laboratory of Water Resources and Environment, Jilin University, Changchun, Jilin 130021, China. Electronic address: dongweihong@jlu.edu.cn.

PMID: 36150598
DOI: 10.1016/j.scitotenv.2022.158956

Abstract

Nitrate is a common pollutant in the aquatic environment. Denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are the main reduction processes of nitrate. In the relatively closed sediment environment, the competitive interaction of these two nitrate reduction determines whether the ecosystem removes or retains nitrogen. In the process of NO₃^--N bioreduction, Magnetite, which is a common mineral present in soil and other sediments can play a crucial role. However, it is still not clear whether magnetite promotes or inhibits NO₃^--N bioreduction. In this paper, the effect of magnetite on NO₃^--N bioreduction was studied by batch experiments. The results show that magnetite can increase the NO₃^--N reduction rate by 1.48 %, and can inhibit the DNRA process at the beginning of the reaction and then promote the DNRA process. Magnetite changed the microbial community structure in our experiment systems. The relative abundance of Sphingomonas, which mainly exists in a high carbon and low nitrogen environment, increased under sufficient carbon source conditions. The relative abundance of Fe-oxidizing and NO₃^--N reducing bacteria, such as Flavobacterium, increased in the absence of carbon sources but in the presence of magnetite. In addition, magnetite can significantly increase activity of the microbial electron transport system (ETS). the added microbial electronic activity of magnetite increased nearly two-fold under the same experiment conditions. The acid produced by the metabolisms of Pseudomonas and Acinetobacter further promotes the dissolution of magnetite, thus increasing the concentration of Fe (II) in the system, which is beneficial to autotrophic denitrifying bacteria and promote the reduction of NO₃^--N. These findings can enhance our understanding of the interaction mechanism between iron minerals and nitrate reducing bacteria during nitrate reduction under natural conditions.

Keywords: DNRA; Denitrification; Magnetite; Microbial community structure; Microorganism.

Publication types

Review

MeSH terms

Ammonium Compounds* / metabolism
Bacteria / metabolism
Carbon / metabolism
Denitrification
Ferrosoferric Oxide
Groundwater*
Microbiota*
Nitrates / analysis
Nitrogen / metabolism
Nitrogen Oxides / metabolism
Oxidation-Reduction

Substances

Nitrates
Ferrosoferric Oxide
Ammonium Compounds
Nitrogen Oxides
Nitrogen
Carbon