Utilization of cathodic hydrogen by hydrogen-oxidizing bacteria

Rajagopal, B. S.; LeGall, Jean

doi:10.1007/bf00257613

Cited by 57 publications

(50 citation statements)

References 24 publications

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“…The reversibility of the cathode reaction may now clearly explain the results obtained already, particularly with the so-called two-bottle experiments [12,26,27]. These experiments have demonstrated that corrosion of steel is enhanced by the consumption of hydrogen from the gas phase by SRB or free hydrogenases contained in a second bottle.…”

Section: Resultssupporting

confidence: 52%

“…This reversibility may explain the influence of hydrogen removal on corrosion rate observed in the two-bottle experiments previously cited [12,26,27]. Reversible hydrogen production implies the existence of a reaction equilibrium that can be shifted if hydrogen concentration near the cathode is modified.…”

Section: Phosphates Srb and Hydrogenase In Anaerobic Biocorrosionmentioning

confidence: 86%

“…The mechanisms proposed to explain anaerobic MIC by SRB include: precipitation of iron sulphide, which next catalyzes proton reduction into molecular hydrogen and acts as a cathode in a galvanic couple with metallic iron [10][11][12]; catalysis of the reduction reaction by a hydrogenase enzyme coming from the bacteria [13]; anodic depolarization resulting from the local acidification at the anode [14]; metal ion chelating by extra cellular polymer substances (EPS) [15] and galvanic coupling with EPS [16]. Some authors have proposed oxygen as the terminal electron acceptor in a more complete model considering various effects of SRB metabolism on steel surfaces in a mixed aerobic/anaerobic system [17][18][19][20][21].…”

Section: Phosphates Srb and Hydrogenase In Anaerobic Biocorrosionmentioning

confidence: 99%

“…The old mechanism, known as cathodic depolarization, where it was assumed that the consumption of molecular hydrogen (issued from the proton or water reduction) by SRB was the rate-limiting step [22], is now considered to be wrong because hydrogen evolution on steel is an irreversible reaction [23][24][25]. However, experimental evidence has been provided of hydrogen removal increasing corrosion [12,26]. In these experiments, steel coupons were immerged in a phosphate solution contained in a bottle connected by the gas phase to another bottle that contained SRB.…”

Section: Phosphates Srb and Hydrogenase In Anaerobic Biocorrosionmentioning

confidence: 99%

“…Such an influence of hydrogen on the corrosion potential is possible only if the reduction reactions (12) and (13) are reversible. So removing hydrogen from the surface of the steel by any process (consumption via SRB respiration or hydrogenase-catalyzed oxidation, physical removal, etc.)…”

Section: Potentiometric Studymentioning

confidence: 99%

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Role of the reversible electrochemical deprotonation of phosphate species in anaerobic biocorrosion of steels

2007

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Sulphate reducing bacteria are known to play a major role in anaerobic microbiological influenced corrosion of steels, but mechanisms behind their influence are still source of debates as certain phenomena remain unexplained. Some experiments have shown that hydrogen consumption by SRB or hydrogenase increased the corrosion rate of mild steel. This was observed only in the presence of phosphate species. Here the cathodic behaviour of phosphate species on steel was studied to elucidate the role of phosphate in anaerobic corrosion of steel. Results showed: a linear correlation between reduction waves in linear voltammetry and phosphate concentration at a constant pH value; that phosphate ions induced considerable anaerobic corrosion of mild steel, which was sensitive to hydrogen concentration in the solution; and that the corrosion potential of stainless steel in presence of phosphate was shifted to more negative values as molecular hydrogen was added to the atmosphere in the reaction vessel. Phosphate species, and possibly other weak acids present in biofilms, are suggested to play an important role in the anaerobic corrosion of steels via a reversible mechanism of electrochemical deprotonation that may be accelerated by hydrogen removal.

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Section: Resultssupporting

confidence: 52%

Section: Phosphates Srb and Hydrogenase In Anaerobic Biocorrosionmentioning

confidence: 86%

Section: Phosphates Srb and Hydrogenase In Anaerobic Biocorrosionmentioning

confidence: 99%

Section: Phosphates Srb and Hydrogenase In Anaerobic Biocorrosionmentioning

confidence: 99%

Section: Potentiometric Studymentioning

confidence: 99%

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Role of the reversible electrochemical deprotonation of phosphate species in anaerobic biocorrosion of steels

2007

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Zero valent iron as an electron‐donor for methanogenesis and sulfate reduction in anaerobic sludge

Karri

Sierra-Álvarez

Field

2005

Biotech & Bioengineering

192

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Zero valent iron (ZVI) is a reactive media commonly utilized in permeable reactive barriers (PRBs). Sulfate reducing bacteria are being considered for the immobilization of heavy metals in PRBs. The purpose of this study was to evaluate the potential of ZVI as an electron donor for sulfate reduction in natural mixed anaerobic cultures. The ability of methanogens to utilize ZVI as an electron-donor was also explored since these microorganisms often compete with sulfate reducers for common substrates. Four grades of ZVI of different particle sizes (1.120, 0.149, 0.044, and 0.010 mm diameter) were compared as electron donor in batch bioassays inoculated with anaerobic bioreactor sludge. Methanogenesis was evaluated in mineral media lacking sulfate. Sulfate reduction was evaluated in mineral media containing sulfate and the specific methanogenic inhibitor, 2-bromoethane sulfonate. ZVI contributed to significant increases in methane production and sulfate reduction-compared to endogenous substrate controls. The rates of methane formation or sulfate reduction were positively correlated with the surface area of ZVI. The highest rates of 0.310 mmol CH4 formed/mol Fe0.day and 0.804 mmol SO4(2-) reduced/mol Fe0.day were obtained with the finest grade of ZVI (0.01 mm). The results demonstrate that ZVI is readily utilized as a slow-release electron donor for methanogenesis and sulfate reduction in anaerobic sludge; and therefore, has a promising potential in bioremediation applications.

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Removal of nitrate and hexavalent uranium from groundwater by sequential treatment in bioreactors packed with elemental sulfur and zero‐valent iron

Luna-Velasco

Sierra-Álvarez

Castro

et al. 2010

Biotech & Bioengineering

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The bioreduction of soluble hexavalent uranium (U(VI)) to insoluble tetravalent uranium (U(IV)) is an attractive bioremediation strategy for the clean-up of contaminated groundwater. High levels of the common occurring co-contaminant, nitrate (NO3(-)), can potentially interfere with uranium bioremediation. In this study, treatment of a synthetic groundwater containing a mixture of NO3(-) and U(VI) was investigated in a sulfur-limestone autotrophic denitrifying (SLAD) bioreactor that was coupled in series with a bioreactor packed with zero-valent iron (Fe(0), ZVI) and sand. An additional aim of the study was to explore the possible role of biological activity in enhancing the reduction of U(VI) by Fe(0). The SLAD reactor removed NO3(-) efficiently (99.8%) at loadings of up to 20 mmol NO3(-) L(r)(-1) d(-1), with near stoichiometric conversion to benign dinitrogen gas (N(2)). The ZVI bioreactor subsequently removed uranium (99.8%) at high (0.22 mM) and low (0.02 mM) influent concentrations of the radionuclide. Aqueous uranium was reliably eliminated to below the maximum contaminant level of 30 µg L(-1) (0.13 µM) when the ZVI reactor was operated at average empty bed hydraulic retention times as low as 2.3 h, demonstrating the feasibility of the sequential treatment strategy in packed bed bioreactors. Sequential extraction of the ZVI reactor packing confirmed that uranium was immobilized as U(IV). Uranium removal was enhanced by microbial activity as confirmed by the increased rate of uranium removal in batch assays inoculated with effluent from the ZVI bioreactor and spiked with Fe(0) compared to abiotic controls.

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Utilization of cathodic hydrogen by hydrogen-oxidizing bacteria

Cited by 57 publications

References 24 publications

Role of the reversible electrochemical deprotonation of phosphate species in anaerobic biocorrosion of steels

Role of the reversible electrochemical deprotonation of phosphate species in anaerobic biocorrosion of steels

Zero valent iron as an electron‐donor for methanogenesis and sulfate reduction in anaerobic sludge

Removal of nitrate and hexavalent uranium from groundwater by sequential treatment in bioreactors packed with elemental sulfur and zero‐valent iron

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