Enzymic versus nonenzymic mechanisms for iron(III) reduction in aquatic sediments

Lovley, Derek R.; Phillips, Elizabeth; Lonergan, Debra J.

doi:10.1021/es00018a007

Cited by 243 publications

(161 citation statements)

References 31 publications

(53 reference statements)

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“…However, when the Fe203 was enclosed in dialysis tubing, which prevented direct contact between Fe(III) and the fermentative Fe(III) reducers, Fe(III) was not reduced even though the accumulation of fermentation acids and the lowering of the measured redox potential were as great as in the Fe(III)-reducing cultures in which contact between microorganisms and hematite was permitted. Similar results have been obtained with S. putrefaciens and goethite (11) and with C. pasteurianum and GS-15 with highly reactive, poorly crystalline Fe(III) oxides (202).…”

Section: Redox Modelsupporting

confidence: 85%

“…Although facultative organisms can metabolize any traces Of 02 in anaerobically prepared media, even down to very low concentrations, there is no Fe(III) reduction during growth of many of these microorganisms (46,272,318). For example, when a strain of E. coli was grown in an anaerobic glucoseFe(III) oxide medium, there was no detectable Fe(III) reduction (202), even though the metabolism of E. coli in the anaerobic medium could be expected to lower the redox potential to -600 mV (146).…”

Section: Redox Modelmentioning

confidence: 99%

“…Some process, presumably microbial Fe(III) reduction, must generate Fe(II) before a low redox potential will be measured. Therefore, the concept of a low redox potential bringing about Fe(III) reduction is probably the reverse of the actual order of events in sedimentary environments (202 (202). Pasteurization of marine sediments inhibited the release of Fe(II) into the interstitial water even though the pasteurization process increased the concentration of dissolved organic carbon more than 10-fold (54).…”

Section: Redox Modelmentioning

confidence: 99%

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Dissimilatory Fe(III) and Mn(IV) Reduction

Lovley

Holmes

Nevin

2004

Advances in Microbial Physiology

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1,061

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Section: Redox Modelsupporting

confidence: 85%

Section: Redox Modelmentioning

confidence: 99%

Section: Redox Modelmentioning

confidence: 99%

See 1 more Smart Citation

Dissimilatory Fe(III) and Mn(IV) Reduction

Lovley

Holmes

Nevin

2004

Advances in Microbial Physiology

Self Cite

1,471

1,061

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“…The reduction of Fe(III) (hydr)oxides plays a central role in the biogeochemistry of anaerobic soils and sediments (1)(2)(3), and microbial (enzymatic) catalysis dominates Fe(III) oxide reduction in nonsulfidogenic sedimentary environments (4). Iron oxides occur in soils and sediments as a spectrum of phases ranging from amorphous materials, such as ferrihydrite, to well-crystallized minerals such as goethite and hematite (5).…”

Section: Introductionmentioning

confidence: 99%

Fe(III) Oxide Reactivity Toward Biological versus Chemical Reduction

Roden

2003

Environ. Sci. Technol.

260

231

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Initial rates of biological (Shewanella putrefaciens strain CN32, pH 6.8) and chemical (ascorbate, pH 3.0) reduction of synthetic Fe(III) oxides with a broad range of crystallinity and specific surface area were examined to assess how variations in these properties are likely to influence the kinetics of bacterial Fe(III) oxide reduction in heterogeneous natural Fe(III) oxide assemblages. The results indicate that bacterial Fe(III) oxide reduction does not respond strongly to oxide crystal thermodynamic properties (∆G f ) which exert a significant impact on the kinetics of abiotic reductive dissolution. These findings suggest that oxide mineral heterogeneity in natural soils and sediments is likely to affect initial rates of bacterial reduction (e.g. during the early stages of anaerobic metabolism following the onset of anoxic conditions) mainly via an influence on reactive surface site density and that inferences regarding the competitiveness of bacterial Fe(III) oxide reduction as a pathway for organic matter oxidation in anoxic environments cannot be based on assumed thermodynamic properties of the dominant oxide phase(s) in the soil or sediment.

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“…An example is the reduction of the Fe 3+ in the iron minerals such goethite or hematite [1][2][3] . The inference that bacteria enhance dissolution rates in nature is based on untested assumption that active bacteria have only one function that affects dissolution: they produce soluble dissolutions-promoting complexing ligants.…”

Section: Lateritic Iron Crust: An Example Of Bioreductionmentioning

confidence: 99%