Iron-Mediated Microbial Oxidation and Abiotic Reduction of Organic Contaminants under Anoxic Conditions

Tobler, Nicole B.; Hofstetter, Thomas B.; Straub, Kristina; Fontana, Daniela; Schwarzenbach, René P.

doi:10.1021/es071128k

Cited by 54 publications

(38 citation statements)

References 38 publications

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“…The finding that there are Geobacter species that can anaerobically degrade benzene supports previous suggestions that Geobacter species play an important role in the removal of benzene and other aro- matic hydrocarbon contaminants from polluted groundwater (6,13,26,44,53,56,58). Methods for genetically manipulating G. metallireducens have recently been developed (49,59), making it the first genetically tractable organism known to be capable of anoxic benzene degradation under strict anaerobic conditions.…”

Section: Resultssupporting

confidence: 81%

Anaerobic Benzene Oxidation by Geobacter Species

Zhang

Bain

Nevin

et al. 2012

Appl Environ Microbiol

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Section: Resultssupporting

confidence: 81%

Anaerobic Benzene Oxidation by Geobacter Species

Zhang

Bain

Nevin

et al. 2012

Appl Environ Microbiol

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“…Numerous experimental studies have pointed out the reactivity of ferrous iron when bound to various oxide minerals (surfacebound Fe(II)) as well as Fe(II) aq in solution toward the reduction of inorganic and organic pollutants. 43,44 For example, surface- bound Fe(II) was found to enhance dramatically the transformation rates of many nitroaromatic, [45][46][47] and polyhalogenated compounds. 48 Depending on the type of mineral-bound Fe(II) and depending on the solution composition (particularly pH), very different transformation rates and, in some cases, different transformation products may be found for a given organic pollutant.…”

Section: Application To the Environmental Sciencementioning

confidence: 99%

Toward robust computational electrochemical predicting the environmental fate of organic pollutants

Sviatenko

Isayev

Gorb³

et al. 2011

J Comput Chem

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A number of density functionals was utilized for the calculation of electron attachment free energy for nitrocompounds, quinones and azacyclic compounds. Different solvation models have been tested on the calculation of difference in free energies of solvation of oxidized and reduced forms of nitrocompounds in aqueous solution, quinones in acetonitrile, and azacyclic compounds in dimethylformamide. Gas-phase free energies evaluated at the mPWB1K/tzvp level and solvation energies obtained using SMD model to compute solvation energies of neutral oxidized forms and PCM(Pauling) to compute solvation energies of anion-radical reduced forms provide reasonable accuracy of the prediction of electron attachment free energy, difference in free solvation energies of oxidized and reduced forms, and as consequence yield reduction potentials in good agreement with experimental data (mean absolute deviation is 0.15 V). It was also found that SMD/M05-2X/tzvp method provides reduction potentials with deviation of 0.12 V from the experimental values but in cases of nitrocompounds and quinones this accuracy is achieved due to the cancelation of errors. To predict reduction ability of naturally occurred iron containing species with respect to organic pollutants we exploited experimental data within the framework of Pourbaix (Eh - pH) diagrams. We conclude that surface-bound Fe(II) as well as certain forms of aqueous Fe(II)aq are capable of reducing a variety of nitroaromatic compounds, quinones and novel high energy materials under basic conditions (pH > 8). At the same time, zero-valent iron is expected to be active under neutral and acidic conditions.

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“…Numerous studies have suggested that Geobacter species play an important role in the removal of aromatic hydrocarbons from contaminated aquifers, anaerobically oxidizing aromatic hydrocarbons to carbon dioxide with the reduction of Fe(III), which is abundant in many subsurface environments (6,(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43). Recently two members of the Geobacteraceae family, Geobacter metallireducens and Geobacter sp.…”

mentioning

confidence: 99%

Anaerobic Benzene Oxidation via Phenol in Geobacter metallireducens

Zhang

Tremblay²,

Chaurasia³

et al. 2013

Appl Environ Microbiol

107

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Anaerobic activation of benzene is expected to represent a novel biochemistry of environmental significance. Therefore, benzene metabolism was investigated in Geobacter metallireducens, the only genetically tractable organism known to anaerobically degrade benzene. Trace amounts (<0.5 M) of phenol accumulated in cultures of Geobacter metallireducens anaerobically oxidizing benzene to carbon dioxide with the reduction of Fe(III). Phenol was not detected in cell-free controls or in Fe(II)-and benzene-containing cultures of Geobacter sulfurreducens, a Geobacter species that cannot metabolize benzene. The phenol produced in G. metallireducens cultures was labeled with 18 O during growth in H 2 18 O, as expected for anaerobic conversion of benzene to phenol. Analysis of whole-genome gene expression patterns indicated that genes for phenol metabolism were upregulated during growth on benzene but that genes for benzoate or toluene metabolism were not, further suggesting that phenol was an intermediate in benzene metabolism. Deletion of the genes for PpsA or PpcB, subunits of two enzymes specifically required for the metabolism of phenol, removed the capacity for benzene metabolism. These results demonstrate that benzene hydroxylation to phenol is an alternative to carboxylation for anaerobic benzene activation and suggest that this may be an important metabolic route for benzene removal in petroleum-contaminated groundwaters, in which Geobacter species are considered to play an important role in anaerobic benzene degradation.

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Iron-Mediated Microbial Oxidation and Abiotic Reduction of Organic Contaminants under Anoxic Conditions

Cited by 54 publications

References 38 publications

Anaerobic Benzene Oxidation by Geobacter Species

Anaerobic Benzene Oxidation by Geobacter Species

Toward robust computational electrochemical predicting the environmental fate of organic pollutants

Anaerobic Benzene Oxidation via Phenol in Geobacter metallireducens

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