Coupling of Fe(II) oxidation in illite with nitrate reduction and its role in clay mineral transformation

Zhao, Linduo; Dong, Hailiang; Edelmann, Richard E.; Zeng, Qiang; Agrawal, Abinash

doi:10.1016/j.gca.2017.01.004

Cited by 43 publications

(20 citation statements)

References 57 publications

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“…The rate and extent of total Fe(II) oxidation, as well as • OH production, were clay-dependent (Figure A-1). rSWy-3, rNAu-2, and rRAr-1 exhibited a fast Fe(II) oxidation rate within the first 4 h, but rIMt-2 and rISCz-1 were barely oxidized over 24 h. This difference in the Fe(II) oxidation rate was consistent with the previous result and was related to the difference in the layer expandability of the clays, with smectite being the most redox active and illite the least . The • OH production patterns were similar to those of Fe(II) oxidation, exhibiting the following order: rRAr-1 > rSWy-3 ≥ rNAu-2 ≫ rIMt-2 ≥ rISCz-1 (Figure A-).…”

Section: Resultssupporting

confidence: 88%

Antibacterial Mechanisms of Reduced Iron-Containing Smectite–Illite Clay Minerals

Guo

Xia

Zeng

et al. 2021

Environ. Sci. Technol.

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Reduced nontronite has been demonstrated to be antibacterial through the production of hydroxyl radical (•OH) from the oxidation of structural Fe(II). Herein, we investigated the antibacterial activity of more common smectite–illite (S–I) clays toward Escherichia coli cells, including montmorillonite SWy-3, illite IMt-2, 50–50 S–I rectorite RAr-1, 30–70 S–I ISCz-1, and nontronite NAu-2. Under an oxic condition, reduced clays (with a prefix r before mineral names) produced reactive oxygen species (ROS), and the antibacterial activity followed the order of rRAr-1 > rSWy-3 ≥ rNAu-2 ≫ rIMt-2 ≥ rISCz-1. The strongest antibacterial activity of rRAr-1 was contributed by a combination of •OH and Fe(IV) generated from structural Fe(II)/adsorbed Fe2+ and soluble Fe2+, respectively. Higher levels of lipid and protein oxidation, intracellular ROS accumulation, and membrane disruption were consistent with this antibacterial mechanism of rRAr-1. The antibacterial activity of other S–I clays depended on layer expandability, which determined the reactivity of structural Fe(II) and the production of •OH, with the expandable smectite being the most antibacterial and nonexpandable illite the least. Our results provide new insights into the antibacterial mechanisms of clay minerals.

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Section: Resultssupporting

confidence: 88%

Antibacterial Mechanisms of Reduced Iron-Containing Smectite–Illite Clay Minerals

Guo

Xia

Zeng

et al. 2021

Environ. Sci. Technol.

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“…Clay minerals such as illite, smectite and nontronite, are also available for Fe(II) oxidation by Desulfitobacterium frappieri (Shelobolina et al, 2003) and by Pseudogulbenkiania sp. strain 2002 (Zhao et al, 2017). Culturing of microbes on solid mineral substrates has, however, proved difficult.…”

Section: Fe(ii) Sources and Fe(iii) Minerologymentioning

confidence: 99%

Microbial anaerobic Fe(II) oxidation – Ecology, mechanisms and environmental implications

Bryce

Blackwell

Schmidt

et al. 2018

Environmental Microbiology

195

123

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Iron is the most abundant redox-active metal in the Earth's crust. The one electron transfer between the two most common redox states, Fe(II) and Fe(III), plays a role in a huge range of environmental processes from mineral formation and dissolution to contaminant remediation and global biogeochemical cycling. It has been appreciated for more than a century that microorganisms can harness the energy of this Fe redox transformation for their metabolic benefit. However, this is most widely understood for anaerobic Fe(III)-reducing or aerobic and microaerophilic Fe(II)-oxidizing bacteria. Only in the past few decades have we come to appreciate that bacteria also play a role in the anaerobic oxidation of ferrous iron, Fe(II), and thus can act to form Fe(III) minerals in anoxic settings. Since this discovery, our understanding of the ecology of these organisms, their mechanisms of Fe(II) oxidation and their role in environmental processes has been increasing rapidly. In this article, we bring these new discoveries together to review the current knowledge on these environmentally important bacteria, and reveal knowledge gaps for future research.

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“…Fe(II) adsorbed to iron-oxide surfaces is a stronger reducing agent than Fe(II) in dissolved form (Stumm and Sulzberger, 1992;Davidson et al, 2003), hence adsorbed Fe(II) might promote NO3reduction in the studied systems. Additionally, biological oxidation of structural Fe(II) in clay minerals, such as illite and nontronite, can be coupled with reduction of NO3to N2 (Zhao et al, 2013;Zhao et al, 2017). In our incubation studies, the dissolved Fe concentration decreased until 27, 18, and 6 days in Riparian 1, Riparian 2, and Stream 1 systems, respectively and then remained almost constant through the end of the experiments.…”

Section: Relationship Between Ph Dissolved Metal Content and Denitrificationmentioning

confidence: 60%

Copper availability governs nitrous oxide accumulation in wetland soils and stream sediments

Sharma¹,

Flynn²,

Catalano³

et al. 2021

Preprint

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Denitrification is microbially-mediated through enzymes containing metal cofactors. Laboratory studies of pure cultures have highlighted that the availability of Cu, required for the multicopper enzyme nitrous oxide reductase, can limit N2O reduction. However, in natural aquatic systems, such as wetlands and hyporheic zones in stream beds, the role of Cu in controlling denitrification remains incompletely understood. In this study, we collected soils and sediments from three natural environments -- riparian wetlands, marsh wetlands, and a stream -- to investigate their nitrogen species transformation activity at background Cu levels and different supplemented Cu loadings. All of the systems displayed low solid-phase associated Cu (40 - 280 nmol g-1), which made them appropriate sites for evaluating the effect of limited Cu availability on denitrification. In laboratory incubation experiments, high concentrations of N2O accumulated in all microcosms lacking Cu amendment except for one stream sediment sample. With Cu added to provide dissolved concentrations at trace levels (10-300 nM), reduction of N2O to N2 in the wetland soils and stream sediments was enhanced. A kinetic model could account for the trends in nitrogen species by combining the reactions for microbial reduction of NO3- to NO2-/N2O/N2 and abiotic reduction of NO2- to N2. The model revealed that the rate of N2O to N2 conversion increased significantly in the presence of Cu. For riparian wetland soils and stream sediments, the kinetic model also suggested that overall denitrification is driven by abiotic reduction of NO2- in the presence of inorganic electron donors. This study demonstrated that natural aquatic systems containing Cu at concentrations less than or equal to crustal abundances may display incomplete reduction of N2O to N2 that would cause N2O accumulation and release to the atmosphere.

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Coupling of Fe(II) oxidation in illite with nitrate reduction and its role in clay mineral transformation

Cited by 43 publications

References 57 publications

Antibacterial Mechanisms of Reduced Iron-Containing Smectite–Illite Clay Minerals

Antibacterial Mechanisms of Reduced Iron-Containing Smectite–Illite Clay Minerals

Microbial anaerobic Fe(II) oxidation – Ecology, mechanisms and environmental implications

Copper availability governs nitrous oxide accumulation in wetland soils and stream sediments

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