Microbial reduction of schwertmannite by co-cultured iron- and sulfate-reducing bacteria

Changdong Ke; Chuling Guo; Siyu Zhang; Yanping Deng; Xiaofei Li; Yuancheng Li; Guining Lu; Fei Ling; Zhi Dang

doi:10.1016/j.scitotenv.2022.160551

Microbial reduction of schwertmannite by co-cultured iron- and sulfate-reducing bacteria

Sci Total Environ. 2023 Feb 25:861:160551. doi: 10.1016/j.scitotenv.2022.160551. Epub 2022 Nov 29.

Authors

Changdong Ke¹, Chuling Guo², Siyu Zhang¹, Yanping Deng¹, Xiaofei Li¹, Yuancheng Li¹, Guining Lu¹, Fei Ling³, Zhi Dang¹

Affiliations

¹ School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006, China.
² School of Environment and Energy, South China University of Technology, Guangzhou 510006, China; The Key Laboratory of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, Guangzhou 510006, China. Electronic address: clguo@scut.edu.cn.
³ School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China.

PMID: 36460112
DOI: 10.1016/j.scitotenv.2022.160551

Abstract

Schwertmannite (Sch) is an iron-hydroxysulfate mineral commonly found in acid mine drainage contaminated environment. The transformation mechanism of Sch mediated by pure cultured iron-reducing bacteria (FeRB) or sulfate-reducing bacteria (SRB) has been studied. However, FeRB and SRB widely coexist in the environment, the mechanism of Sch transformation by the consortia of FeRB and SRB is still unclear. This study investigated the Sch reduction by co-cultured Shewanella oneidensis (FeRB) and Desulfosporosinus meridiei (SRB). The results showed that co-culture of FeRB and SRB could accelerate the reductive dissolution of Sch, but not synergistically, and there were two distinct phases in the reduction of Sch mediated by FeRB and SRB: an initial phase in which FeRB predominated and Fe³⁺ in Sch was reduced, accompanied with the release of SO₄^2-, and the detected secondary minerals were mainly vivianite; the second phase in which SRB predominated and mediated the reduction of SO₄^2-, producing minerals including mackinawite and siderite in addition to vivianite. Compared to pure culture, the abundance of FeRB and SRB in the consortia decreased, and more minerals aggregated inside and outside the cell; correspondingly, the transcription levels of genes (cymA, omcA, and mtrCBA) related to Fe³⁺ reduction in co-culture was down-regulated, while the transcription levels of SO₄^2--reducing genes (sat, aprAB, dsr(C)) was generally up-regulated. These phenomena suggested that secondary minerals produced in co-culture limited but did not inhibit bacterial growth, and the presence of SRB was detrimental to dissimilatory Fe³⁺ reduction, while existed FeRB was in favor of dissimilatory SO₄^2- reduction. SRB mediated SO₄^2- reduction by up-regulating the expression of SO₄^2- reduction-related genes when its abundance was limited, which may be a strategy to cope with external coercion. These findings allow for a better understanding of the process and mechanism of microbial mediated reduction of Sch in the environment.

Keywords: Co-culture; Desulfosporosinus meridiei; Schwertmannite; Shewanella oneidensis.

MeSH terms

Bacteria / metabolism
Coculture Techniques
Desulfovibrio* / metabolism
Ferric Compounds / metabolism
Iron* / metabolism
Minerals / metabolism
Oxidation-Reduction
Sulfates / metabolism

Substances

Iron
schwertmannite
ferrous phosphate
Ferric Compounds
Minerals
Sulfates