Formation and Transformation of Iron‐Bearing Minerals by Iron(II)‐Oxidizing and Iron(III)‐Reducing Bacteria

Miot, Jennyfer; Etique, Marjorie

doi:10.1002/9783527691395.ch4

Cited by 23 publications

(28 citation statements)

References 301 publications

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“…51 A wide array of Fe oxides can also form through biomineralization. 52 In the cathodic mode, lower amounts of cytochromes are used in comparison to the amount in anodic mode. As such, in the cathodic mode excess Fe(III) from the cytochromes may be reduced to Fe(II) as part of the bacterial metabolic process.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Disparity of Cytochrome Utilization in Anodic and Cathodic Extracellular Electron Transfer Pathways of Geobacter sulfurreducens Biofilms

et al. 2020

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Extracellular electron transfer (EET) in microorganisms is prevalent in nature and has been utilized in functional bioelectrochemical systems. EET of Geobacter sulf urreducens has been extensively studied and has been revealed to be facilitated through c-type cytochromes, which mediate charge between the electrode and G. sulfurreducens in anodic mode. However, the EET pathway of cathodic conversion of fumarate to succinate is still under debate. Here, we apply a variety of analytical methods, including electrochemistry, UV−vis absorption and resonance Raman spectroscopy, quartz crystal microbalance with dissipation, and electron microscopy, to understand the involvement of cytochromes and other possible electron-mediating species in the switching between anodic and cathodic reaction modes. By switching the applied bias for a G. sulfurreducens biofilm coupled to investigating the quantity and function of cytochromes, as well as the emergence of Fecontaining particles on the cell membrane, we provide evidence of a diminished role of cytochromes in cathodic EET. This work sheds light on the mechanisms of G. sulfurreducens biofilm growth and suggests the possible existence of a nonheme, iron-involving EET process in cathodic mode.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Disparity of Cytochrome Utilization in Anodic and Cathodic Extracellular Electron Transfer Pathways of Geobacter sulfurreducens Biofilms

et al. 2020

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“…Cell wall surfaces are usually negatively charged and can thus offer binding sites for cations such as dissolved Fe 2+ . In addition, the periplasm is also a dedicated site for Fe 2+ -mineral precipitation as shown for iron-oxidizing bacteria (Miot et al, 2009c;Miot and Etique, 2016) and sulfate-reducing bacteria (Watson et al, 2000;Picard et al, 2018;Stanley and Southam, 2018). Sulfide released by sulfate-reducing bacteria would have promoted iron sulfide precipitation on the cell surface and/or within their periplasm, resulting in bacteria encrustation.…”

Section: First Stages Of Iron Sulfide Formation (1 Week)mentioning

confidence: 99%

Mechanisms of Pyrite Formation Promoted by Sulfate-Reducing Bacteria in Pure Culture

et al. 2020

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Pyrite, or iron disulfide, is the most common sulfide mineral on the Earth's surface and is widespread through the geological record. Because sulfides are mainly produced by sulfate-reducing bacteria (SRB) in modern sedimentary environments, microorganisms are assumed to drive the formation of iron sulfides, in particular, pyrite. However, the exact role played by microorganisms in pyrite formation remains unclear and, to date, the precipitation of pyrite in microbial cultures has only rarely been achieved. The present work relies on chemical monitoring, electron microscopy, X-ray diffraction, and synchrotron-based spectroscopy to evaluate the formation of iron sulfides by the sulfate-reducing bacteria Desulfovibrio desulfuricans as a function of the source of iron, either provided as dissolved Fe 2+ or as Fe III-phosphate nanoparticles. Dissolved ferrous iron led to the formation of increasingly crystalline mackinawite (FeS) with time, encrusting bacterial cell walls, hence preventing further sulfate reduction upon day 5 and any evolution of iron sulfides into more stable phases, e.g., pyrite. In contrast, ferric phosphate was transformed into a mixture of large flattened crystals of well-crystallized vivianite (Fe 3 (PO 4) 2 • 8H 2 O) and a biofilm-like thin film of poorly crystallized mackinawite. Although being hosted in the iron sulfide biofilm, most cells were not encrusted. Excess sulfide delivered by the bacteria and oxidants (such as polysulfides) promoted the evolution of mackinawite into greigite (Fe 3 S 4) and the nucleation of pyrite spherules. These spherules were several hundreds of nanometers wide and occurred within the extracellular polymeric substance (EPS) of the biofilm after only 1 month. Altogether, the present study demonstrates that the mineral assemblage induced by the metabolic activity of sulfate-reducing bacteria strongly depends on the source of iron, which has strong implications for the interpretation of the presence of pyrite and vivianite in natural environments.

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“…The mineralogy of biogenic Fe(III) minerals is dependent on a myriad of variables ranging from the microbial species, growth medium (i.e., phosphate or buffer concentrations), substrate availability, as well as geochemical and physical conditions such as pH and temperature (Posth et al, 2014;Miot and Etique, 2016). Because solution chemistry is such a strong driver in biogenic mineral precipitation, the same strain of bacteria, Acidovorax sp.…”

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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Formation and Transformation of Iron‐Bearing Minerals by Iron(II)‐Oxidizing and Iron(III)‐Reducing Bacteria

Cited by 23 publications

References 301 publications

Disparity of Cytochrome Utilization in Anodic and Cathodic Extracellular Electron Transfer Pathways of Geobacter sulfurreducens Biofilms

Disparity of Cytochrome Utilization in Anodic and Cathodic Extracellular Electron Transfer Pathways of Geobacter sulfurreducens Biofilms

Mechanisms of Pyrite Formation Promoted by Sulfate-Reducing Bacteria in Pure Culture

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

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