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Sample records for sulfate reducing bacteria

  1. Study examines sulfate-reducing bacteria activity

    SciTech Connect

    McElhiney, J.E.; Hardy, J.A.; Rizk, T.Y.; Stott, J.F.D.; Eden, R.D.

    1996-12-09

    Low-sulfate seawater injection can reduce the potential of an oil reservoir turning sour because of sulfate-reducing bacteria. Sulfate-reducing bacteria (SRB) convert sulfate ions in seawater used in waterflooding into sulfide with the concomitant oxidation of a carbon source. A recent study at Capcis investigated the efficiency of SRB under various conditions of sulfate limitation. This study was conducted in a flowing bioreactor at 2,000 psia with different temperature zones (mesophilic 35 C and thermophilic 60--80 C). The study mixed microfloral populations derived from real North Sea-produced fluids, and included an active population of marine methanogenic bacteria present to provide competition for the available carbon sources. In general, results showed that SRB continue to convert sulfate to sulfide in stoichiometric quantities without regard to absolute concentrations. The paper discusses the results and recommends nanofiltration of seawater for ``sweet`` reservoirs.

  2. Nitrate reduction in sulfate-reducing bacteria.

    PubMed

    Marietou, Angeliki

    2016-08-01

    Sulfate-reducing bacteria (SRBs) gain their energy by coupling the oxidation of organic substrate to the reduction of sulfate to sulfide. Several SRBs are able to use alternative terminal electron acceptors to sulfate such as nitrate. Nitrate-reducing SRBs have been isolated from a diverse range of environments. In order to be able to understand the significance of nitrate reduction in SRBs, we need to examine the ecology and physiology of the nitrate-reducing SRB isolates. PMID:27364687

  3. Sulfate-reducing bacteria: Microbiology and physiology

    NASA Technical Reports Server (NTRS)

    Peck, H. D.

    1985-01-01

    The sulfate reducing bacteria, the first nonphotosynthetic anaerobic bacteria demonstrated to contain c type cytochromes, perform electron transfer coupled to phosphorylation. A new bioenergetic scheme for the formation of a proton gradient for growth of Desulfovibrio on organic substrates and sulfate involving vectors electron transfer and consistent with the cellular localization of enzymes and electron transfer components was proposed. Hydrogen is produced in the cytoplasm from organic substrates and, as a permease molecule diffuses rapidly across the cytoplasmic membrane, it is oxidized to protons and electrons by the periplasmic hydrogenase. The electrons only are transferred across the cytoplasmic membrane to the cytoplasm where they are used to reduce sulfate to sulfide. The protons are used for transport or to drive a reversible ATPOSE. The net effect is the transfer of protons across the cytoplasmic membrane with the intervention of a proton pump. This type of H2 cycling is relevant to the bioenergetics of other types of anaerobic microorganisms.

  4. Monitoring sulfide and sulfate-reducing bacteria

    SciTech Connect

    Tanner, R.S.

    1995-12-31

    Simple yet precise and accurate methods for monitoring sulfate-reducing bacteria (SRB) and sulfide remain useful for the study of bacterial souring and corrosion. Test kits are available to measure sulfide in field samples. A more precise methylene blue sulfide assay for both field and laboratory studies is described here. Improved media, compared to that in API RP-38, for enumeration of SRB have been formulated. One of these, API-RST, contained cysteine (1.1 mM) as a reducing agent, which may be a confounding source of sulfide. While cysteine was required for rapid enumeration of SRB from environmental samples, the concentration of cysteine in medium could be reduced to 0.4 mM. It was also determined that elevated levels of yeast extract (>1 g/liter) could interfere with enumeration of SRB from environmental samples. The API-RST medium was modified to a RST-11 medium. Other changes in medium composition, in addition to reduction of cysteine, included reduction of the concentration of phosphate from 3.4 mM to 2.2 mM, reduction of the concentration of ferrous iron from 0.8 mM to 0.5 mM and preparation of a stock mineral solution to ease medium preparation. SRB from environmental samples could be enumerated in a week in this medium.

  5. Isolation of Sulfate-Reducing Bacteria from Human Thoracoabdominal Pus

    PubMed Central

    Loubinoux, Julien; Jaulhac, Benoit; Piemont, Yves; Monteil, Henri; Le Faou, Alain E.

    2003-01-01

    To evaluate the prevalence of sulfate-reducing bacteria in septic processes, we searched for these bacteria by culture in 100 consecutive abdominal and pleural pus specimens. Twelve isolates were obtained from abdominal samples and were identified by a multiplex PCR as Desulfovibrio piger (formerly Desulfomonas pigra) (seven strains), Desulfovibrio fairfieldensis (four strains), and Desulfovibrio desulfuricans (one strain). PMID:12624073

  6. [Regulation of sulfates, hydrogen sulfide and heavy metals in technogenic reservoirs by sulfate-reducing bacteria].

    PubMed

    Hudz', S P; Peretiatko, T B; Moroz, O M; Hnatush, S O; Klym, I R

    2011-01-01

    Sulfate-reducing bacteria Desulfovibrio desulfuricans Ya-11 in the presence of sulfates and organic compounds in the medium reduce sulfates to hydrogen sulfide (dissimilatory sulfate reduction). Heavy metals in concentration over 2 mM inhibit this process. Pb2+, Zn2+, Ni2+, Co2+, Fe2+ and Cd2+ ions in concentration 1-1.5 mM display insignificant inhibiting effect on sulfate reduction process, and metals precipitate in the form of sulfides. At concentrations of heavy metals 2-3 mM one can observe a decrease of sulfates reduction intensity, and a percent of metals binding does not exceed 72%. Obtained results give reason to confirm, that sulfate-reducing bacteria play an important role in regulation of the level of sulfates, hydrogen sulfide and heavy metals in reservoirs and they may be used for purification of water environment from these compounds. PMID:21598657

  7. Methods for Engineering Sulfate Reducing Bacteria of the Genus Desulfovibrio

    SciTech Connect

    Chhabra, Swapnil R; Keller, Kimberly L.; Wall, Judy D.

    2011-03-15

    Sulfate reducing bacteria are physiologically important given their nearly ubiquitous presence and have important applications in the areas of bioremediation and bioenergy. This chapter provides details on the steps used for homologous-recombination mediated chromosomal manipulation of Desulfovibrio vulgaris Hildenborough, a well-studied sulfate reducer. More specifically, we focus on the implementation of a 'parts' based approach for suicide vector assembly, important aspects of anaerobic culturing, choices for antibiotic selection, electroporation-based DNA transformation, as well as tools for screening and verifying genetically modified constructs. These methods, which in principle may be extended to other sulfate-reducing bacteria, are applicable for functional genomics investigations, as well as metabolic engineering manipulations.

  8. Remediation of Acid Mine Drainage with Sulfate Reducing Bacteria

    ERIC Educational Resources Information Center

    Hauri, James F.; Schaider, Laurel A.

    2009-01-01

    Sulfate reducing bacteria have been shown to be effective at treating acid mine drainage through sulfide production and subsequent precipitation of metal sulfides. In this laboratory experiment for undergraduate environmental chemistry courses, students design and implement a set of bioreactors to remediate acid mine drainage and explain observed…

  9. Remediation of acid mine drainage with sulfate reducing bacteria

    SciTech Connect

    Hauri, J.F.; Schaider, L.A.

    2009-02-15

    Sulfate reducing bacteria have been shown to be effective at treating acid mine drainage through sulfide production and subsequent precipitation of metal sulfides. In this laboratory experiment for undergraduate environmental chemistry courses, students design and implement a set of bioreactors to remediate acid mine drainage and explain observed changes in dissolved metal concentrations and pH. Using synthetic acid mine drainage and combinations of inputs, students monitor their bioreactors for decreases in dissolved copper and iron concentrations.

  10. Commensal symbiosis between agglutinated polychaetes and sulfate-reducing bacteria.

    PubMed

    Guido, A; Mastandrea, A; Rosso, A; Sanfilippo, R; Tosti, F; Riding, R; Russo, F

    2014-05-01

    Pendant bioconstructions occur within submerged caves in the Plemmirio Marine Protected Area in SE Sicily, Italy. These rigid structures, here termed biostalactites, were synsedimentarily lithified by clotted-peloidal microbial carbonate that has a high bacterial lipid biomarker content with abundant compounds derived from sulfate-reducing bacteria. The main framework builders are polychaete serpulid worms, mainly Protula with subordinate Semivermilia and Josephella. These polychaetes have lamellar and/or fibrillar wall structure. In contrast, small agglutinated terebellid tubes, which are a minor component of the biostalactites, are discontinuous and irregular with a peloidal micritic microfabric. The peloids, formed by bacterial sulfate reduction, appear to have been utilized by terebellids to construct tubes in an environment where other particulate sediment is scarce. We suggest that the bacteria obtained food from the worms in the form of fecal material and/or from the decaying tissue of surrounding organisms and that the worms obtained peloidal micrite with which to construct their tubes, either as grains and/or as tube encompassing biofilm. Peloidal worm tubes have rarely been reported in the recent but closely resemble examples in the geological record that extend back at least to the early Carboniferous. This suggests a long-lived commensal relationship between some polychaete worms and heterotrophic, especially sulfate-reducing, bacteria. PMID:24636469

  11. Revisiting Modes of energy generation in sulfate reducing bacteria

    SciTech Connect

    Joachimiak, Marcin; Chakraborty, Romy; Zhou, Aifen; Fortney, Julian; Geller, Jil; Wall, Judy; Zhou, Jizhong; Arkin, Adam; Hazen, Terry; Keasling, Jay; Chhabra, Swapnil

    2010-05-17

    Sulfate reducing bacteria (SRB) play an important role in global sulfur and carbon cycling through their ability to completely mineralize organic matter while respiring sulfate to hydrogen sulfide. They are ubiquitous in anaerobic environments and have the ability to reduce toxic metals like Cr(VI) and U(VI). While SRB have been studied for over three decades, bioenergetic modes of this group of microbes are poorly understood. Desulfovibrio vulgaris strain Hildenborough (DvH) has served as a model SRB over the last decade with the accumulation of transcriptomic, proteomic and metabolic data under a wide variety of stressors. To further investigate the three hypothesized modes of energy generation in this anaerobe we conducted a systematic study involving multiple electron donor and acceptor combinations for growth. DvH was grown at 37oC in a defined medium with (a) lactate + thiosulfate, (b) lactate + sulfite (c) lactate + sulfate, (d) pyruvate + sulfate, (e) H2 + acetate + sulfate, (f) formate + acetate + sulfate, g) formate + sulfate and (h) pyruvate fermentation. Cells were harvested at mid-log phase of growth for all conditions for transcriptomics, when the optical density at 600nm was in the range 0.42-0.5. Initial results indicate that cells grown on lactate do not appear to significantly differentiate their gene expression profiles when presented with different electron acceptors. These profiles however differ significantly from those observed during growth with other electron donors such as H2 and formate, as well as during fermentative growth. Together the gene expression changes in the presence of different electron donors provide insights into the ability of DvH to differentially reduce metals such as Cr(VI). Here we present revised modes of energy generation in DvH in light of this new transcriptomic evidence.

  12. Corrosion control in the presence of sulfate-reducing bacteria

    SciTech Connect

    Schick, G. )

    1990-07-01

    Impressed current and magnesium anode-type cathodic protection usually provide appreciable protection to the buried and underground telephone plant. However, in the laboratory, a medium containing sulfate-reducing bacteria (SRB) strongly reduces the output current from the magnesium anode. This explains the lack of success with magnesium anodes in the field where the ratio of protected surface area to current output is orders of magnitude higher than in the laboratory test. Low concentrations of sodium hypochlorite (NaOCl) additive to the solution provide minimal protection. However, high concentrations and/or aeration can eliminate the high concentration of SRB in the aqueous medium.

  13. Suitability of fluorescence measurements to quantify sulfate-reducing bacteria.

    PubMed

    Barton, Larry L; Carpenter, Claire M

    2013-06-01

    Fluorescence activity has been used to identify Desulfovibrio and has been termed the 'desulfoviridin test'. This fluorescence is attributed to the prosthetic group of bisulfite reductase, a key enzyme in dissimilatory sulfate reduction. We have pursued the use of fluorescence measurements to quantify sulfate-reducing bacteria. Cells of D. desulfuricans and D. gigas were treated with NaOH and produced two fluorescence spectra: one with maximum fluorescence with an excitation at 395 nm and an emission at 605 nm and another with an excitation at 320 nm and emission at 360 nm. Using the fluorescence with excitation at 395 nm and emission at 605 nm, we explored a series of parameters to measure Desulfovibrio in pure cultures and environmental samples. Fluorescence measurements are reliable provided the cells are treated with 1.75 N NaOH and the chromophore released from the cells is not exposed to strong light intensity, and is not exposed to temperatures greater than 20 °C, and measurements are done within a few minutes of extraction. Bleaching of fluorescence was attributed to metal ions in solution which was not observed until metal concentrations reached 1.5mM. We propose that D. desulfuricans is appropriate as the reference organism for measurement of sulfate-reducing bacteria by fluorescence and by using fluorescence intensity, 10(5) cells/ml can be readily detected in environmental samples. PMID:23566827

  14. Biochemistry, physiology and biotechnology of sulfate-reducing bacteria.

    PubMed

    Barton, Larry L; Fauque, Guy D

    2009-01-01

    Chemolithotrophic bacteria that use sulfate as terminal electron acceptor (sulfate-reducing bacteria) constitute a unique physiological group of microorganisms that couple anaerobic electron transport to ATP synthesis. These bacteria (220 species of 60 genera) can use a large variety of compounds as electron donors and to mediate electron flow they have a vast array of proteins with redox active metal groups. This chapter deals with the distribution in the environment and the major physiological and metabolic characteristics of sulfate-reducing bacteria (SRB). This chapter presents our current knowledge of soluble electron transfer proteins and transmembrane redox complexes that are playing an essential role in the dissimilatory sulfate reduction pathway of SRB of the genus Desulfovibrio. Environmentally important activities displayed by SRB are a consequence of the unique electron transport components or the production of high levels of H(2)S. The capability of SRB to utilize hydrocarbons in pure cultures and consortia has resulted in using these bacteria for bioremediation of BTEX (benzene, toluene, ethylbenzene and xylene) compounds in contaminated soils. Specific strains of SRB are capable of reducing 3-chlorobenzoate, chloroethenes, or nitroaromatic compounds and this has resulted in proposals to use SRB for bioremediation of environments containing trinitrotoluene and polychloroethenes. Since SRB have displayed dissimilatory reduction of U(VI) and Cr(VI), several biotechnology procedures have been proposed for using SRB in bioremediation of toxic metals. Additional non-specific metal reductase activity has resulted in using SRB for recovery of precious metals (e.g. platinum, palladium and gold) from waste streams. Since bacterially produced sulfide contributes to the souring of oil fields, corrosion of concrete, and discoloration of stonework is a serious problem, there is considerable interest in controlling the sulfidogenic activity of the SRB. The

  15. Pathway of Fermentative Hydrogen Production by Sulfate-reducing Bacteria

    SciTech Connect

    Wall, Judy D.

    2015-02-16

    Biofuels are a promising source of sustainable energy. Such biofuels are intermediate products of microbial metabolism of renewable substrates, in particular, plant biomass. Not only are alcohols and solvents produced in this degradative process but energy-rich hydrogen as well. Non photosynthetic microbial hydrogen generation from compounds other than sugars has not been fully explored. We propose to examine the capacity of the abundant soil anaerobes, sulfate-reducing bacteria, for hydrogen generation from organic acids. These apparently simple pathways have yet to be clearly established. Information obtained may facilitate the exploitation of other microbes not yet readily examined by molecular tools. Identification of the flexibility of the metabolic processes to channel reductant to hydrogen will be useful in consideration of practical applications. Because the tools for genetic and molecular manipulation of sulfate-reducing bacteria of the genus Desulfovibrio are developed, our efforts will focus on two strains, D. vulgaris Hildenborough and Desulfovibrio G20.Therefore total metabolism, flux through the pathways, and regulation are likely to be limiting factors which we can elucidate in the following experiments.

  16. Enzymatic iron and uranium reduction by sulfate-reducing bacteria

    USGS Publications Warehouse

    Lovley, D.R.; Roden, E.E.; Phillips, E.J.P.; Woodward, J.C.

    1993-01-01

    The potential for sulfate-reducing bacteria (SRB) to enzymatically reduce Fe(III) and U(VI) was investigated. Five species of Desulfovibrio as well as Desulfobacterium autotrophicum and Desulfobulbus propionicus reduced Fe(III) chelated with nitrilotriacetic acid as well as insoluble Fe(III) oxide. Fe(III) oxide reduction resulted in the accumulation of magnetite and siderite. Desulfobacter postgatei reduced the chelated Fe(III) but not Fe(III) oxide. Desulfobacter curvatus, Desulfomonile tiedjei, and Desulfotomaculum acetoxidans did not reduce Fe(III). Only Desulfovibrio species reduced U(VI). U(VI) reduction resulted in the precipitation of uraninite. None of the SRB that reduced Fe(III) or U(VI) appeared to conserve enough energy to support growth from this reaction. However, Desulfovibrio desulfuricans metabolized H2 down to lower concentrations with Fe(III) or U(VI) as the electron acceptor than with sulfate, suggesting that these metals may be preferred electron acceptors at the low H2 concentrations present in most marine sediments. Molybdate did not inhibit Fe(III) reduction by D. desulfuricans. This indicates that the inability of molybdate to inhibit Fe(III) reduction in marine sediments does not rule out the possibility that SRB are important catalysts for Fe(III) reduction. The results demonstrate that although SRB were previously considered to reduce Fe(III) and U(VI) indirectly through the production of sulfide, they may also directly reduce Fe(III) and U(VI) through enzymatic mechanisms. These findings, as well as our recent discovery that the So-reducing microorganism Desulfuromonas acetoxidans can reduce Fe(III), demonstrate that there are close links between the microbial sulfur, iron, and uranium cycles in anaerobic marine sediments. ?? 1993.

  17. SULFATE-REDUCING BACTERIA IN THE SEAGRASS RHIZOSPHERE

    EPA Science Inventory

    Seagrasses are rooted in anoxic sediments that support high levels of microbial activity including utilization of sulfate as a terminal electron acceptor which is reduced to sulfide. Sulfate reduction in seagrass bed sediments is stimulated by input of organic carbon through the ...

  18. Anaerobic degradation of benzene by marine sulfate-reducing bacteria

    NASA Astrophysics Data System (ADS)

    Musat, Florin; Wilkes, Heinz; Musat, Niculina; Kuypers, Marcel; Widdel, Friedrich

    2010-05-01

    Benzene, the archetypal aromatic hydrocarbon is a common constituent of crude oil and oil-refined products. As such, it can enter the biosphere through natural oil seeps or as a consequence of exploitation of fossil fuel reservoirs. Benzene is chemically very stable, due to the stabilizing aromatic electron system and to the lack of functional groups. Although the anaerobic degradation of benzene has been reported under denitrifying, sulfate-reducing and methanogenic conditions, the microorganisms involved and the initial biochemical steps of degradation remain insufficiently understood. Using marine sediment from a Mediterranean lagoon a sulfate-reducing enrichment culture with benzene as the sole organic substrate was obtained. Application of 16S rRNA gene-based methods showed that the enrichment was dominated (more than 85% of total cells) by a distinct phylotype affiliated with a clade of Deltaproteobacteria that include degraders of other aromatic hydrocarbons, such as naphthalene, ethylbenzene and m-xylene. Using benzoate as a soluble substrate in agar dilution series, several pure cultures closely related to Desulfotignum spp. and Desulfosarcina spp. were isolated. None of these strains was able to utilize benzene as a substrate and hybridizations with specific oligonucleotide probes showed that they accounted for as much as 6% of the total cells. Incubations with 13C-labeled benzene followed by Halogen in situ Hybridization - Secondary Ion Mass Spectroscopy (HISH-SIMS) analysis showed that cells of the dominant phylotype were highly enriched in 13C, while the accompanying bacteria had little or no 13C incorporation. These results demonstrate that the dominant phylotype was indeed the apparent benzene degrader. Dense-cell suspensions of the enrichment culture did not show metabolic activity toward added phenol or toluene, suggesting that benzene degradation did not proceed through anaerobic hydroxylation or methylation. Instead, benzoate was identified in

  19. Modeling Reduction of Uranium U(VI) under Variable Sulfate Concentrations by Sulfate-Reducing Bacteria

    PubMed Central

    Spear, John R.; Figueroa, Linda A.; Honeyman, Bruce D.

    2000-01-01

    The kinetics for the reduction of sulfate alone and for concurrent uranium [U(VI)] and sulfate reduction, by mixed and pure cultures of sulfate-reducing bacteria (SRB) at 21 ± 3°C were studied. The mixed culture contained the SRB Desulfovibrio vulgaris along with a Clostridium sp. determined via 16S ribosomal DNA analysis. The pure culture was Desulfovibrio desulfuricans (ATCC 7757). A zero-order model best fit the data for the reduction of sulfate from 0.1 to 10 mM. A lag time occurred below cell concentrations of 0.1 mg (dry weight) of cells/ml. For the mixed culture, average values for the maximum specific reaction rate, Vmax, ranged from 2.4 ± 0.2 μmol of sulfate/mg (dry weight) of SRB · h−1) at 0.25 mM sulfate to 5.0 ± 1.1 μmol of sulfate/mg (dry weight) of SRB · h−1 at 10 mM sulfate (average cell concentration, 0.52 mg [dry weight]/ml). For the pure culture, Vmax was 1.6 ± 0.2 μmol of sulfate/mg (dry weight) of SRB · h−1 at 1 mM sulfate (0.29 mg [dry weight] of cells/ml). When both electron acceptors were present, sulfate reduction remained zero order for both cultures, while uranium reduction was first order, with rate constants of 0.071 ± 0.003 mg (dry weight) of cells/ml · min−1 for the mixed culture and 0.137 ± 0.016 mg (dry weight) of cells/ml · min−1 (U0 = 1 mM) for the D. desulfuricans culture. Both cultures exhibited a faster rate of uranium reduction in the presence of sulfate and no lag time until the onset of U reduction in contrast to U alone. This kinetics information can be used to design an SRB-dominated biotreatment scheme for the removal of U(VI) from an aqueous source. PMID:10966381

  20. Stable carbon isotope fractionation by sulfate-reducing bacteria

    NASA Technical Reports Server (NTRS)

    Londry, Kathleen L.; Des Marais, David J.

    2003-01-01

    Biogeochemical transformations occurring in the anoxic zones of stratified sedimentary microbial communities can profoundly influence the isotopic and organic signatures preserved in the fossil record. Accordingly, we have determined carbon isotope discrimination that is associated with both heterotrophic and lithotrophic growth of pure cultures of sulfate-reducing bacteria (SRB). For heterotrophic-growth experiments, substrate consumption was monitored to completion. Sealed vessels containing SRB cultures were harvested at different time intervals, and delta(13)C values were determined for gaseous CO(2), organic substrates, and products such as biomass. For three of the four SRB, carbon isotope effects between the substrates, acetate or lactate and CO(2), and the cell biomass were small, ranging from 0 to 2 per thousand. However, for Desulfotomaculum acetoxidans, the carbon incorporated into biomass was isotopically heavier than the available substrates by 8 to 9 per thousand. SRB grown lithoautotrophically consumed less than 3% of the available CO(2) and exhibited substantial discrimination (calculated as isotope fractionation factors [alpha]), as follows: for Desulfobacterium autotrophicum, alpha values ranged from 1.0100 to 1.0123; for Desulfobacter hydrogenophilus, the alpha value was 0.0138, and for Desulfotomaculum acetoxidans, the alpha value was 1.0310. Mixotrophic growth of Desulfovibrio desulfuricans on acetate and CO(2) resulted in biomass with a delta(13)C composition intermediate to that of the substrates. The extent of fractionation depended on which enzymatic pathways were used, the direction in which the pathways operated, and the growth rate, but fractionation was not dependent on the growth phase. To the extent that environmental conditions affect the availability of organic substrates (e.g., acetate) and reducing power (e.g., H(2)), ecological forces can also influence carbon isotope discrimination by SRB.

  1. Mechanistic modeling of biocorrosion caused by biofilms of sulfate reducing bacteria and acid producing bacteria.

    PubMed

    Xu, Dake; Li, Yingchao; Gu, Tingyue

    2016-08-01

    Biocorrosion is also known as microbiologically influenced corrosion (MIC). Most anaerobic MIC cases can be classified into two major types. Type I MIC involves non-oxygen oxidants such as sulfate and nitrate that require biocatalysis for their reduction in the cytoplasm of microbes such as sulfate reducing bacteria (SRB) and nitrate reducing bacteria (NRB). This means that the extracellular electrons from the oxidation of metal such as iron must be transported across cell walls into the cytoplasm. Type II MIC involves oxidants such as protons that are secreted by microbes such as acid producing bacteria (APB). The biofilms in this case supply the locally high concentrations of oxidants that are corrosive without biocatalysis. This work describes a mechanistic model that is based on the biocatalytic cathodic sulfate reduction (BCSR) theory. The model utilizes charge transfer and mass transfer concepts to describe the SRB biocorrosion process. The model also includes a mechanism to describe APB attack based on the local acidic pH at a pit bottom. A pitting prediction software package has been created based on the mechanisms. It predicts long-term pitting rates and worst-case scenarios after calibration using SRB short-term pit depth data. Various parameters can be investigated through computer simulation. PMID:27071053

  2. MOLECULAR PHYLOGENETIC AND BIOGEOCHEMICAL STUDIES OF SULFATE-REDUCING BACTERIA IN THE RHIZOSPHERE OF SPARTINA ALTERNIFLORA

    EPA Science Inventory

    The population composition and biogeochemistry of sulfate-reducing bacteria (SRB) in the rhizosphere of the marsh grass Spartina alterniflora was investigated over two growing seasons using molecular probing, enumerations of culturable SRB, and measurements of SO42- reduction rat...

  3. Suspended culture of sulfate reducing bacteria for the remediation of acid mine drainage

    SciTech Connect

    Misken, K.A.; Figueroa, L.A.

    1993-12-31

    Acid mind drainages are characterized by low pH, and high sulfate and heavy metals concentrations. Conventional treatment technologies address these concerns with high chemical additions producing large volumes of sludge requiring disposal. An anaerobic suspended culture of sulfate reducing bacteria can reduce the metals and sulfate levels by reducing sulfate to sulfide levels by reducing sulfate to sulfate, which can then form precipates with the metal in solution, while increase pH and producing biocarbonate. Readily available and inexpensive organic carbon sources such as wastewater and waste beer were evaluated in serum bottles, and a bench scale sequencing batch reactor was operated using molasses as the organic source. Up to 90% sulfate removal was achieved while reducing iron concentrations to below detection limits. Increases in pH require production of stoichiometrically excess sulfide.

  4. Sulfate-reducing bacteria and their activities in cyanobacterial mats of solar lake (Sinai, Egypt).

    PubMed

    Teske, A; Ramsing, N B; Habicht, K; Fukui, M; Küver, J; Jørgensen, B B; Cohen, Y

    1998-08-01

    The sulfate-reducing bacteria within the surface layer of the hypersaline cyanobacterial mat of Solar Lake (Sinai, Egypt) were investigated with combined microbiological, molecular, and biogeochemical approaches. The diurnally oxic surface layer contained between 10(6) and 10(7) cultivable sulfate-reducing bacteria ml-1 and showed sulfate reduction rates between 1,000 and 2, 200 nmol ml-1 day-1, both in the same range as and sometimes higher than those in anaerobic deeper mat layers. In the oxic surface layer and in the mat layers below, filamentous sulfate-reducing Desulfonema bacteria were found in variable densities of 10(4) to 10(6) cells ml-1. A Desulfonema-related, diurnally migrating bacterium was detected with PCR and denaturing gradient gel electrophoresis within and below the oxic surface layer. Facultative aerobic respiration, filamentous morphology, motility, diurnal migration, and aggregate formation were the most conspicuous adaptations of Solar Lake sulfate-reducing bacteria to the mat matrix and to diurnal oxygen stress. A comparison of sulfate reduction rates within the mat and previously published photosynthesis rates showed that CO2 from sulfate reduction in the upper 5 mm accounted for 7 to 8% of the total photosynthetic CO2 demand of the mat. PMID:9687455

  5. Novel processes for anaerobic sulfate production from elemental sulfur by sulfate-reducing bacteria

    USGS Publications Warehouse

    Lovley, D.R.; Phillips, E.J.P.

    1994-01-01

    Sulfate reducers and related organisms which had previously been found to reduce Fe(III) with H2 or organic electron donors oxidized S0 to sulfate when Mn(IV) was provided as an electron acceptor. Organisms catalyzing this reaction in washed cell suspensions included Desulfovibrio desulfuricans, Desulfomicrobium baculatum. Desulfobacterium autotrophicum, Desulfuromonas acetoxidans, and Geobacter metallireducens. These organisms produced little or no sulfate from S0 with Fe(III) as a potential electron acceptor or in the absence of an electron acceptor. In detailed studies with Desulfovibrio desulfuricans, the stoichiometry of sulfate and Mn(II) production was consistent with the reaction S0 + 3 MnO2 + 4H+ ???SO42- + 3Mn(II) + 2H2O. None of the organisms evaluated could be grown with S0 as the sole electron donor and Mn(IV) as the electron acceptor. In contrast to the other sulfate reducers evaluated, Desulfobulbus propionicus produced sulfate from S0 in the absence of an electron acceptor and Fe(III) oxide stimulated sulfate production. Sulfide also accumulated in the absence of Mn(IV) or Fe(III). The stoichiometry of sulfate and sulfide production indicated that Desulfobulbus propionicus disproportionates S0 as follows: 4S0 + 4H2O???SO42- + 3HS- + 5 H+. Growth of Desulfobulbus propionicus with S0 as the electron donor and Fe(III) as a sulfide sink and/or electron acceptor was very slow. The S0 oxidation coupled to Mn(IV) reduction described here provides a potential explanation for the Mn(IV)-dependent sulfate production that previous studies have observed in anoxic marine sediments. Desulfobulbus propionicus is the first example of a pure culture known to disproportionate S0.

  6. A Revised Isotope Fractionation Model for Dissimilatory Sulfate Reduction in Sulfate Reducing Bacteria

    NASA Astrophysics Data System (ADS)

    Benjamin, B.; Bernasconi, S. M.

    2004-12-01

    Sulfur isotope fractionation during dissimilatory sulfate reduction is related to the stepwise reduction of sulfate to sulfide within the cells of the bacteria. The magnitude of fractionation is dependent on the interplay between different reduction steps in a chain of reactions. One of the most intriguing questions in sulfur isotope geochemistry stems from the observation that in natural environments, sulfides are commonly depleted in 34S by -45\\permil to -70\\permil relative to sulfate whereas maximum sulfur isotope difference between produced sulfides and sulfate of around -46\\permil have been obtained in laboratory cultures. A maximum fractionation of 47\\permil was also predicted by the model of sulfate reduction introduced by Rees (1973). The Rees model is commonly accepted but since its introduction, new information about sulfate reduction and isotope fractionation processes has become available in the literature that demands an update of some of its assumptions. We present a improved model for bacterial sulfate reduction which includes revised fractionation factors for the sulfite-sulfide step, a multi-step reduction of sulfite to sulfide including reverse flows and an exchange flux of sulfide between the cell and ambient water. With this model we show that, contrary to the model of Rees (1973), isotope fractionations well in excess of -47\\permil are possible. Therefore, some of the large sulfur isotope fractionations observed in nature may be explained without the need of alternate pathways involving the oxidative sulfur cycle as proposed by Canfield and Thamdrup (1994). In particular, we speculate that large fractionations should occur under hypersulfidic conditions and substrate limitation. We obviously do not disregard the involvement of processes related to the oxidative cycle of sulfur in near-surface environments, but our model suggests that this is not a prerequisite condition to obtain large isotope fractionations. References: Canfield D. E. and

  7. Separation and concentration of hazardous metals from aqueous solutions using sulfate-reducing bacteria

    SciTech Connect

    Apel, W.A.; Wiebe, M.R.; Dugan, P.R.

    1990-01-01

    The removal of metals from aqueous solutions using sulfate-reducing bacteria was investigated. The sulfate-reducing bacteria utilized consisted of a consortium isolated from oil well brine. The consortium was capable of using lactate as a carbon and energy source and producing significant quantities of sulfide which reacted with solubilized metals to form insoluble metal sulfides. After formation, the metal sulfides were removed from solution via filtration. A variety of solubilized metals including lead, cadmium, cobalt, copper, iron, and chromium were removed from solution using sulfate-reducing bacteria. Removal efficiencies varied from metal to metal with lead exhibiting the highest levels of removal and chromium the lowest. 13 refs., 9 figs.

  8. Activated sludge as substrate for sulfate-reducing bacteria in acid mine drainage treatment

    SciTech Connect

    Al-Ani, W.A.G.; Henry, J.G.; Prasad, D.

    1996-11-01

    Acid mine drainage (AMD), characterized by high concentrations of sulfates and heavy metals and low pH, presents a potential hazard to the environment.Several treatment processes (chemical precipitation, ion exchange, reverse osmosis, electrodialysis and electrolytic recovery) are available, but these are often too expensive. Biological treatment of AMD, mediated by sulfate-reducing bacteria (SRB), seems promising. The objective of this study was to use activated sludge as a carbon source for the SRB and determine the most effective COD/sulfate ratio and hydraulic retention time (HRT) for reducing sulfate. Such information would be useful for the application of the proposed two-stage system to AMD treatment. Since the aim of this study was to obtain sulfate reduction and to avoid methane production, it was decided to operate the digesters initially at low COD/SO{sub 4}{sup 2{minus}} ratios of 1.0, 1.5, and 2.0.

  9. A revised isotope fractionation model for dissimilatory sulfate reduction in sulfate reducing bacteria

    NASA Astrophysics Data System (ADS)

    Brunner, Benjamin; Bernasconi, Stefano M.

    2005-10-01

    Sulfur isotope fractionation during dissimilatory sulfate reduction has been conceptually described by the widely accepted Rees model as related to the stepwise reduction of sulfate to sulfide within the cells of bacteria. The magnitude of isotope fractionation is determined by the interplay between different reduction steps in a chain of reactions. Here we present a revision of Rees' model for bacterial sulfate reduction that includes revised fractionation factors for the sulfite-sulfide step and incorporates new forward and reverse steps in the reduction of sulfite to sulfide, as well as exchange of sulfide between the cell and ambient water. With this model we show that in contrast to the Rees model, isotope fractionations well in excess of -46‰ are possible. Therefore, some of the large sulfur isotope fractionations observed in nature can be explained without the need of alternate pathways involving the oxidative sulfur cycle. We use this model to predict that large fractionations should occur under hypersulfidic conditions and where electron acceptor concentrations are limiting.

  10. Phylogenetic Characteristics of Sulfate-reducing Bacteria Having Ability to Reduce Polysulfide

    SciTech Connect

    Takahashi, Yui; Suto, Koichi; Inoue, Chihiro; Chida, Tadashi

    2006-05-15

    To find an efficient bacterium, which has the strong capacity to produce hydrogen sulfide from polysulfide as the waste of process generating hydrogen from hydrogen sulfide by photocatalytic reaction using sun light, is very important for constructing hydrogen producing system. 10 strains of sulfate-reducing bacteria (SRB), which can reduce polysulfide directly, have been isolated from various natural samples such as TCE contaminated soil, soil and sludge around hot spring environment, and the cooling tower of a geothermal plant. This study describes physiological and phylogenetic characterization of SRB which can reduce polysulfide. All of isolates had the ability to reduce polusulfide but these reduction rates were difference depend on isolates. Phylogetetically, all of isolates located difference position for general SRB including Desulfovibrio desulfuricans, which is used standard strain in this study, so they do not belong to Proteobacteria. These have close relation to the genus Desulfotomaculum which can reduce elemental sulfur. It suggests that the ability of reducing elemental sulfur is important for reducing polysulfide to hydrogen sulfide.

  11. Phylogenetic Characteristics of Sulfate-reducing Bacteria Having Ability to Reduce Polysulfide

    NASA Astrophysics Data System (ADS)

    Takahashi, Yui; Suto, Koichi; Inoue, Chihiro; Chida, Tadashi

    2006-05-01

    To find an efficient bacterium, which has the strong capacity to produce hydrogen sulfide from polysulfide as the waste of process generating hydrogen from hydrogen sulfide by photocatalytic reaction using sun light, is very important for constructing hydrogen producing system. 10 strains of sulfate-reducing bacteria (SRB), which can reduce polysulfide directly, have been isolated from various natural samples such as TCE contaminated soil, soil and sludge around hot spring environment, and the cooling tower of a geothermal plant. This study describes physiological and phylogenetic characterization of SRB which can reduce polysulfide. All of isolates had the ability to reduce polusulfide but these reduction rates were difference depend on isolates. Phylogetetically, all of isolates located difference position for general SRB including Desulfovibrio desulfuricans, which is used standard strain in this study, so they do not belong to Proteobacteria. These have close relation to the genus Desulfotomaculum which can reduce elemental sulfur. It suggests that the ability of reducing elemental sulfur is important for reducing polysulfide to hydrogen sulfide.

  12. Methanogenic archaea and sulfate reducing bacteria co-cultured on acetate: teamwork or coexistence?

    PubMed Central

    Ozuolmez, Derya; Na, Hyunsoo; Lever, Mark A.; Kjeldsen, Kasper U.; Jørgensen, Bo B.; Plugge, Caroline M.

    2015-01-01

    Acetate is a major product of fermentation processes and an important substrate for sulfate reducing bacteria and methanogenic archaea. Most studies on acetate catabolism by sulfate reducers and methanogens have used pure cultures. Less is known about acetate conversion by mixed pure cultures and the interactions between both groups. We tested interspecies hydrogen transfer and coexistence between marine methanogens and sulfate reducers using mixed pure cultures of two types of microorganisms. First, Desulfovibrio vulgaris subsp. vulgaris (DSM 1744), a hydrogenotrophic sulfate reducer, was cocultured together with the obligate aceticlastic methanogen Methanosaeta concilii using acetate as carbon and energy source. Next, Methanococcus maripaludis S2, an obligate H2- and formate-utilizing methanogen, was used as a partner organism to M. concilii in the presence of acetate. Finally, we performed a coexistence experiment between M. concilii and an acetotrophic sulfate reducer Desulfobacter latus AcSR2. Our results showed that D. vulgaris was able to reduce sulfate and grow from hydrogen leaked by M. concilii. In the other coculture, M. maripaludis was sustained by hydrogen leaked by M. concilii as revealed by qPCR. The growth of the two aceticlastic microbes indicated co-existence rather than competition. Altogether, our results indicate that H2 leaking from M. concilii could be used by efficient H2-scavengers. This metabolic trait, revealed from coculture studies, brings new insight to the metabolic flexibility of methanogens and sulfate reducers residing in marine environments in response to changing environmental conditions and community compositions. Using dedicated physiological studies we were able to unravel the occurrence of less obvious interactions between marine methanogens and sulfate-reducing bacteria. PMID:26074892

  13. Anaerobic metabolism of nitroaromatic compounds by sulfate-reducing and methanogenic bacteria

    SciTech Connect

    Boopathy, R.; Kulpa, C.F.

    1994-06-01

    Ecological observations suggest that sulfate-reducing and methanogenic bacteria might metabolize nitroaromatic compounds under anaerobic conditions if appropriate electron donors and electron acceptors are present in the environment, but this ability had not been demonstrated until recently. Most studies on the microbial metabolism of nitroaromatic compounds used aerobic microorganisms. In most cases no mineralization of nitroaromatics occurs, and only superficial modifications of the structures are reported. However, under anaerobic sulfate-reducing conditions, the nitroaromatic compounds reportedly undergo a series of reductions with the formation of amino compounds. For example, trinitrotoluene under sulfate-reducing conditions is reduced to triaminotoluene by the enzyme nitrite reductase, which is commonly found in many Desulfovibrio spp. The removal of ammonia from triaminotoluene is achieved by reductive deamination catalyzed by the enzyme reductive deaminase, with the production of ammonia and toluene. Some sulfate reducers can metabolize toluene to CO{sub 2}. Similar metabolic processes could be applied to other nitroaromatic compounds like nitrobenzene, nitrobenzoic acids, nitrophenols, and aniline. Many methanogenic bacteria can reduce nitroaromatic compounds to amino compounds. In this paper we review the anaerobic metabolic processes of nitroaromatic compounds under sulfate-reducing And methanogenic conditions.

  14. Impact of elevated nitrate on sulfate-reducing bacteria: A comparative study of Desulfovibrio vulgaris

    SciTech Connect

    He, Q.; He, Z.; Joyner, D.C.; Joachimiak, M.; Price, M.N.; Yang, Z.K.; Yen, H.-C. B.; Hemme, C. L.; Chen, W.; Fields, M.; Stahl, D. A.; Keasling, J. D.; Keller, M.; Arkin, A. P.; Hazen, T. C.; Wall, J. D.; Zhou, J.

    2010-07-15

    Sulfate-reducing bacteria have been extensively studied for their potential in heavy-metal bioremediation. However, the occurrence of elevated nitrate in contaminated environments has been shown to inhibit sulfate reduction activity. Although the inhibition has been suggested to result from the competition with nitrate-reducing bacteria, the possibility of direct inhibition of sulfate reducers by elevated nitrate needs to be explored. Using Desulfovibrio vulgaris as a model sulfate-reducing bacterium, functional genomics analysis reveals that osmotic stress contributed to growth inhibition by nitrate as shown by the upregulation of the glycine/betaine transporter genes and the relief of nitrate inhibition by osmoprotectants. The observation that significant growth inhibition was effected by 70 mM NaNO{sub 3} but not by 70 mM NaCl suggests the presence of inhibitory mechanisms in addition to osmotic stress. The differential expression of genes characteristic of nitrite stress responses, such as the hybrid cluster protein gene, under nitrate stress condition further indicates that nitrate stress response by D. vulgaris was linked to components of both osmotic and nitrite stress responses. The involvement of the oxidative stress response pathway, however, might be the result of a more general stress response. Given the low similarities between the response profiles to nitrate and other stresses, less-defined stress response pathways could also be important in nitrate stress, which might involve the shift in energy metabolism. The involvement of nitrite stress response upon exposure to nitrate may provide detoxification mechanisms for nitrite, which is inhibitory to sulfate-reducing bacteria, produced by microbial nitrate reduction as a metabolic intermediate and may enhance the survival of sulfate-reducing bacteria in environments with elevated nitrate level.

  15. COMPUTER SIMULATOR (BEST) FOR DESIGNING SULFATE-REDUCING BACTERIA FIELD BIOREACTORS

    EPA Science Inventory

    BEST (bioreactor economics, size and time of operation) is a spreadsheet-based model that is used in conjunction with public domain software, PhreeqcI. BEST is used in the design process of sulfate-reducing bacteria (SRB) field bioreactors to passively treat acid mine drainage (A...

  16. Mine Waste Technology Program. In Situ Source Control Of Acid Generation Using Sulfate-Reducing Bacteria

    EPA Science Inventory

    This report summarizes the results of the Mine Waste Technology Program (MWTP) Activity III, Project 3, In Situ Source Control of Acid Generation Using Sulfate-Reducing Bacteria, funded by the U.S. Environmental Protection Agency (EPA) and jointly administered by EPA and the U.S....

  17. DESIGNING SULFATE-REDUCING BACTERIA FIELD BIOREACTORS USING THE BEST MODEL

    EPA Science Inventory

    BEST (bioreactor economics, size and time of operation) is a spreadsheet-based model that is used in conjunction with a public domain computer software package, PHREEQCI. BEST is intended to be used in the design process of sulfate-reducing bacteria (SRB)field bioreactors to pas...

  18. DESIGNING SULFATE-REDUCING BACTERIA FIELD-BIOREACTORS USING THE BEST MODEL

    EPA Science Inventory

    DESIGNING SULFATE-REDUCING BACTERIA FIELD-BIOREACTORS USING THE BEST MODEL

    Marek H. Zaluski1,3, Brian T. Park1, Diana R. Bless2

    1 MSE Technology Applications; 200 Technology Way, Butte, Montana 59701, USA
    2 U.S. EPA, Office of Research and Development, Cincinna...

  19. Activity and Diversity of Sulfate-Reducing Bacteria in a Petroleum Hydrocarbon-Contaminated Aquifer

    PubMed Central

    Kleikemper, Jutta; Schroth, Martin H.; Sigler, William V.; Schmucki, Martina; Bernasconi, Stefano M.; Zeyer, Josef

    2002-01-01

    Microbial sulfate reduction is an important metabolic activity in petroleum hydrocarbon (PHC)-contaminated aquifers. We quantified carbon source-enhanced microbial SO42− reduction in a PHC-contaminated aquifer by using single-well push-pull tests and related the consumption of sulfate and added carbon sources to the presence of certain genera of sulfate-reducing bacteria (SRB). We also used molecular methods to assess suspended SRB diversity. In four consecutive tests, we injected anoxic test solutions (1,000 liters) containing bromide as a conservative tracer, sulfate, and either propionate, butyrate, lactate, or acetate as reactants into an existing monitoring well. After an initial incubation period, 1,000 liters of test solution-groundwater mixture was extracted from the same well. Average total test duration was 71 h. We measured concentrations of bromide, sulfate, and carbon sources in native groundwater as well as in injection and extraction phase samples and characterized the SRB population by using fluorescence in situ hybridization (FISH) and denaturing gradient gel electrophoresis (DGGE). Enhanced sulfate reduction concomitant with carbon source degradation was observed in all tests. Computed first-order rate coefficients ranged from 0.19 to 0.32 day−1 for sulfate reduction and from 0.13 to 0.60 day−1 for carbon source degradation. Sulfur isotope fractionation in unconsumed sulfate indicated that sulfate reduction was microbially mediated. Enhancement of sulfate reduction due to carbon source additions in all tests and variability of rate coefficients suggested the presence of specific SRB genera and a high diversity of SRB. We confirmed this by using FISH and DGGE. A large fraction of suspended bacteria hybridized with SRB-targeting probes SRB385 plus SRB385-Db (11 to 24% of total cells). FISH results showed that the activity of these bacteria was enhanced by addition of sulfate and carbon sources during push-pull tests. However, DGGE profiles

  20. Transcriptional analysis of sulfate reducing and chemolithoautotrophic sulfur oxidizing bacteria in the deep subseafloor.

    PubMed

    Orsi, William D; Barker Jørgensen, Bo; Biddle, Jennifer F

    2016-08-01

    Sulfate reducing bacteria (SRB) oxidize a significant proportion of subseafloor organic carbon, but their metabolic activities and subsistence mechanisms are poorly understood. Here, we report in depth phylogenetic and metabolic analyses of SRB transcripts in the Peru Margin subseafloor and interpret these results in the context of sulfate reduction activity in the sediment. Relative abundance of overall SRB gene transcripts declines strongly whereas relative abundance of ribosomal protein transcripts from sulfate reducing δ-Proteobacteria peak at 90 m below seafloor (mbsf) within a deep sulfate methane transition zone. This coincides with isotopically heavy δ(34) S values of pore water sulfate (70‰), indicating active subseafloor microbial sulfate reduction. Within the shallow sulfate reduction zone (0-5 mbsf), a transcript encoding the beta subunit of dissimilatory sulfite reductase (dsrB) was related to Desulfitobacterium dehalogenans and environmental sequences from Aarhus Bay (Denmark). At 159 mbsf we discovered a transcript encoding the reversely operating dissimilatory sulfite reductase α-subunit (rdsrA), with basal phylogenetic relation to the chemolithoautotrophic SUP05 Group II clade. A diversity of SRB transcripts involved in cellular maintenance point toward potential subsistence mechanisms under low-energy over long time periods, and provide a detailed new picture of SRB activities underlying sulfur cycling in the deep subseafloor. PMID:26991974

  1. Characterization of metabolic performance of methanogenic granules treating brewery wastewater: role of sulfate-reducing bacteria.

    PubMed Central

    Wu, W M; Hickey, R F; Zeikus, J G

    1991-01-01

    Granules from an upflow anaerobic sludge blanket system treating a brewery wastewater that contained mainly ethanol, propionate, and acetate as carbon sources and sulfate (0.6 to 1.0 mM) were characterized for their physical and chemical properties, metabolic performance on various substrates, and microbial composition. Transmission electron microscopic examination showed that at least three types of microcolonies existed inside the granules. One type consisted of Methanothrix-like rods with low levels of Methanobacterium-like rods; two other types appeared to be associations between syntrophic-like acetogens and Methanobacterium-like organisms. The granules were observed to be have numerous vents or channels on the surface that extended into the interior portions of the granules that may be involved in release of gas formed within the granules. The maximum substrate conversion rates (millimoles per gram of volatile suspended solids per day) at 35 degrees C in the absence of sulfate were 45.1, 8.04, 4.14, and 5.75 for ethanol, acetate, propionate, and glucose, respectively. The maximum methane production rates (millimoles per gram of volatile suspended solids per day) from H2-CO2 and formate were essentially equal for intact granules (13.7 and 13.5) and for physically disrupted granules (42 and 37). During syntrophic ethanol conversion, both hydrogen and formate were formed by the granules. The concentrations of these two intermediates were maintained at a thermodynamic equilibrium, indicating that both are intermediate metabolites in degradation. Formate accumulated and was then consumed during methanogenesis from H2-CO2. Higher concentrations of formate accumulated in the absence of sulfate than in the presence of sulfate. The addition of sulfate (8 to 9 mM) increased the maximum substrate degradation rates for propionate and ethanol by 27 and 12%, respectively. In the presence of this level of sulfate, sulfate-reducing bacteria did not play a significant role in

  2. Temperature effect on acetate and propionate consumption by sulfate-reducing bacteria in saline wastewater.

    PubMed

    van den Brand, T P H; Roest, K; Brdjanovic, D; Chen, G H; van Loosdrecht, M C M

    2014-05-01

    Seawater toilet flushing, seawater intrusion in the sewerage, and discharge of sulfate-rich industrial effluents elevates sulfate content in wastewater. The application of sulfate-reducing bacteria (SRB) in wastewater treatment is very beneficial; as for example, it improves the pathogen removal and reduces the volume of waste sludge, energy requirement and costs. This paper evaluates the potential to apply biological sulfate reduction using acetate and propionate to saline sewage treatment in moderate climates. Long-term biological sulfate reduction experiments at 10 and 20 °C were conducted in a sequencing batch reactor with synthetic saline domestic wastewater. Subsequently, acetate and propionate (soluble organic carbon) conversion rate were determined in both reactors, in the presence of either or both fatty acids. Both acetate and propionate consumption rates by SRB were 1.9 times lower at 10 °C than at 20 °C. At 10 °C, propionate was incompletely oxidized to acetate. At 10 °C, complete removal of soluble organic carbon requires a significantly increased hydraulic retention time as compared to 20 °C. The results of the study showed that biological sulfate reduction can be a feasible and promising process for saline wastewater treatment in moderate climate. PMID:24463759

  3. Nickel, manganese and copper removal by a mixed consortium of sulfate reducing bacteria at a high COD/sulfate ratio.

    PubMed

    Barbosa, L P; Costa, P F; Bertolino, S M; Silva, J C C; Guerra-Sá, R; Leão, V A; Teixeira, M C

    2014-08-01

    The use of sulfate-reducing bacteria (SRB) in passive treatments of acidic effluents containing heavy metals has become an attractive alternative biotechnology. Treatment efficiency may be linked with the effluent conditions (pH and metal concentration) and also to the amount and nature of the organic substrate. Variations on organic substrate and sulfate ratios clearly interfere with the biological removal of this ion by mixed cultures of SRB. This study aimed to cultivate a mixed culture of SRB using different lactate concentrations at pH 7.0 in the presence of Ni, Mn and Cu. The highest sulfate removal efficiency obtained was 98 %, at a COD/sulfate ratio of 2.0. The organic acid analyses indicated an acetate accumulation as a consequence of lactate degradation. Different concentrations of metals were added to the system at neutral pH conditions. Cell proliferation and sulfate consumption in the presence of nickel (4, 20 and 50 mg l(-1)), manganese (1.5, 10 and 25 mg l(-1)) and copper (1.5, 10 and 25 mg l(-1)) were measured. The presence of metals interfered in the sulfate biological removal however the concentration of sulfide produced was high enough to remove over 90 % of the metals in the environment. The molecular characterization of the bacterial consortium based on dsrB gene sequencing indicated the presence of Desulfovibrio desulfuricans, Desulfomonas pigra and Desulfobulbus sp. The results here presented indicate that this SRB culture may be employed for mine effluent bioremediation due to its potential for removing sulfate and metals, simultaneously. PMID:24710619

  4. Adaptation of Psychrophilic and Psychrotrophic Sulfate-Reducing Bacteria to Permanently Cold Marine Environments

    PubMed Central

    Isaksen, M. F.; Jorgensen, B. B.

    1996-01-01

    The potential for sulfate reduction at low temperatures was examined in two different cold marine sediments, Mariager Fjord (Denmark), which is permanently cold (3 to 6(deg)C) but surrounded by seasonally warmer environments, and the Weddell Sea (Antarctica), which is permanently below 0(deg)C. The rates of sulfate reduction were measured by the (sup35)SO(inf4)(sup2-) tracer technique at different experimental temperatures in sediment slurries. In sediment slurries from Mariager Fjord, sulfate reduction showed a mesophilic temperature response which was comparable to that of other temperate environments. In sediment slurries from Antarctica, the metabolic activity of psychrotrophic bacteria was observed with a respiration optimum at 18 to 19(deg)C during short-term incubations. However, over a 1-week incubation, the highest respiration rate was observed at 12.5(deg)C. Growth of the bacterial population at the optimal growth temperature could be an explanation for the low temperature optimum of the measured sulfate reduction. The potential for sulfate reduction was highest at temperatures well above the in situ temperature in all experiments. The results from sediment incubations were compared with those obtained from pure cultures of sulfate-reducing bacteria by using the psychrotrophic strain ltk10 and the mesophilic strain ak30. The psychrotrophic strain reduced sulfate optimally at 28(deg)C in short-term incubations, even though it could not grow at temperatures above 24(deg)C. Furthermore, this strain showed its highest growth yield between 0 and 12(deg)C. In contrast, the mesophilic strain ak30 respired and grew optimally and showed its highest growth yield at 30 to 35(deg)C. PMID:16535228

  5. Sulfate-reducing bacteria mediate thionation of diphenylarsinic acid under anaerobic conditions.

    PubMed

    Guan, Ling; Shiiya, Ayaka; Hisatomi, Shihoko; Fujii, Kunihiko; Nonaka, Masanori; Harada, Naoki

    2015-02-01

    Diphenylarsinic acid (DPAA) is often found as a toxic intermediate metabolite of diphenylchloroarsine or diphenylcyanoarsine that were produced as chemical warfare agents and were buried in soil after the World Wars. In our previous study Guan et al. (J Hazard Mater 241-242:355-362, 2012), after application of sulfate and carbon sources, anaerobic transformation of DPAA in soil was enhanced with the production of diphenylthioarsinic acid (DPTAA) as a main metabolite. This study aimed to isolate and characterize anaerobic soil microorganisms responsible for the metabolism of DPAA. First, we obtained four microbial consortia capable of transforming DPAA to DPTAA at a high transformation rate of more than 80% after 4 weeks of incubation. Sequencing for the bacterial 16S rRNA gene clone libraries constructed from the consortia revealed that all the positive consortia contained Desulfotomaculum acetoxidans species. In contrast, the absence of dissimilatory sulfite reductase gene (dsrAB) which is unique to sulfate-reducing bacteria was confirmed in the negative consortia showing no DPAA reduction. Finally, strain DEA14 showing transformation of DPAA to DPTAA was isolated from one of the positive consortia. The isolate was assigned to D. acetoxidans based on the partial 16S rDNA sequence analysis. Thionation of DPAA was also carried out in a pure culture of a known sulfate-reducing bacterial strain, Desulfovibrio aerotolerans JCM 12613(T). These facts indicate that sulfate-reducing bacteria are microorganisms responsible for the transformation of DPAA to DPTAA under anaerobic conditions. PMID:25228086

  6. Reduction and precipitation of neptunium(V) by sulfate-reducing bacteria.

    SciTech Connect

    Banaszak, J. E.; Rittmann, B. E.; Reed, D. T.

    1999-10-21

    Migration of neptunium, as NpO{sub 2}{sup +}, has been identified as a potentially important pathway for actinide release at nuclear waste repositories and existing sites of subsurface contamination. Reduction of Np(V) to Np(IV) will likely reduce its volubility, resulting in lowered subsurface migration. The ability of sulfate-reducing bacteria (SRB) to utilize Np(V) as an electron acceptor was investigated, because these bacteria are active in many anaerobic aquifers and are known to facilitate the reduction of metals and radionuclides. Pure and mixed cultures of SRB were able to precipitate neptunium during utilization of pyruvate, lactate, and hydrogen as electron donors in the presence and absence of sulfate. The neptunium in the precipitate was identified as Np(IV) using X-ray absorption near edge spectroscopy (XANES) analysis. In mixed-culture studies, the addition of hydrogen to consortia grown by pyruvate fermentation stimulated neptunium reduction and precipitation. Experiments with pure cultures of Desulfovibrio vulgaris, growing by lactate fermentation in the absence of sulfate or by sulfate reduction, confirm that the organism is active in neptunium reduction and precipitation. Based on our results, the activity of SRB in the subsurface may have a significant, and potentially beneficial, impact on actinide mobility by reducing neptunium volubility.

  7. Development of Microarrays-Based Metagenomics Technology for Monitoring Sulfate-Reducing Bacteria in Subsurface Environments

    SciTech Connect

    Cindy, Shi

    2015-07-17

    At the contaminated DOE sites, sulfate-reducing bacteria (SRB) are a significant population and play an important role in the microbial community during biostimulation for metal reduction. However, the diversity, structure and dynamics of SRB communities are poorly understood. Therefore, this project aims to use high throughput sequencing-based metagenomics technologies for characterizing the diversity, structure, functions, and activities of SRB communities by developing genomic and bioinformatics tools to link the SRB biodiversity with ecosystem functioning.

  8. A Scanning Auger Microprobe analysis of corrosion products associated with sulfate reducing bacteria

    SciTech Connect

    Sadowski, R.A.; Chen, G.; Clayton, C.R.; Kearns, J.R.; Gillow, J.B.; Francis, A.J.

    1995-03-01

    A Scanning Auger Microprobe analysis was performed on the corrosion products of an austenitic AISI type 304 SS after a potentiostatic polarization of one volt for ten minutes in a modified Postgate`s C media containing sulfate reducing bacteria. The corrosion products were characterized and mapped in local regions where pitting was observed. A critical evaluation of the applicability of this technique for the examination of microbially influenced corrosion (MIC) is presented.

  9. Treatment of antimony mine drainage: challenges and opportunities with special emphasis on mineral adsorption and sulfate reducing bacteria.

    PubMed

    Li, Yongchao; Hu, Xiaoxian; Ren, Bozhi

    2016-01-01

    The present article summarizes antimony mine distribution, antimony mine drainage generation and environmental impacts, and critically analyses the remediation approach with special emphasis on iron oxidizing bacteria and sulfate reducing bacteria. Most recent research focuses on readily available low-cost adsorbents, such as minerals, wastes, and biosorbents. It is found that iron oxides prepared by chemical methods present superior adsorption ability for Sb(III) and Sb(V). However, this process is more costly and iron oxide activity can be inhibited by plenty of sulfate in antimony mine drainage. In the presence of sulfate reducing bacteria, sulfate can be reduced to sulfide and form Sb(2)S(3) precipitates. However, dissolved oxygen and lack of nutrient source in antimony mine drainage inhibit sulfate reducing bacteria activity. Biogenetic iron oxide minerals from iron corrosion by iron-oxidizing bacteria may prove promising for antimony adsorption, while the micro-environment generated from iron corrosion by iron oxidizing bacteria may provide better growth conditions for symbiotic sulfate reducing bacteria. Finally, based on biogenetic iron oxide adsorption and sulfate reducing bacteria followed by precipitation, the paper suggests an alternative treatment for antimony mine drainage that deserves exploration. PMID:27148704

  10. Sulfate-reducing bacteria in human feces and their association with inflammatory bowel diseases.

    PubMed

    Loubinoux, Julien; Bronowicki, Jean-Pierre; Pereira, Ines A C; Mougenel, Jean-Louis; Faou, Alain E

    2002-05-01

    We have searched for sulfate-reducing bacteria in the feces of 41 healthy individuals and 110 patients from a Hepato-Gastro-Enterology Unit using a specific liquid medium (Test-kit Labège, Compagnie Française de Géothermie, Orléans, France). The 110 patients were separated in 22 patients presenting with inflammatory bowel diseases and 88 patients hospitalized for other lower (n=30) or upper (n=58) digestive tract diseases. Sulfate-reducing bacteria were isolated from 10 healthy individuals (24%), 15 patients presenting with inflammatory bowel diseases (68%), and 33 patients with other symptoms (37%). A multiplex PCR was devised for the identification of Desulfovibrio piger (formerly Desulfomonas pigra), Desulfovibrio fairfieldensis and Desulfovibrio desulfuricans, and applied to the above isolates. The strains of sulfate-reducing bacteria consisted of D. piger (39 isolates), D. fairfieldensis (19 isolates) and D. desulfuricans (one isolate). The prevalence of D. piger was significantly higher in inflammatory bowel disease patients (55%) as compared to healthy individuals (12%) or patients with other symptoms (25%) (P<0.05). PMID:19709217

  11. Promotion of Ni2+ Removal by Masking Toxicity to Sulfate-Reducing Bacteria: Addition of Citrate

    PubMed Central

    Qian, Junwei; Zhu, Xiaoyu; Tao, Yong; Zhou, Yan; He, Xiaohong; Li, Daping

    2015-01-01

    The sulfate-reducing bioprocess is a promising technology for the treatment of heavy metal-containing wastewater. This work was conducted to investigate the possibility of promoting heavy metal removal by the addition of citrate to mask Ni2+ toxicity to sulfate-reducing bacteria (SRB) in batch reactors. SRB growth was completely inhibited in Ni2+-containing medium (1 mM) when lactate served as the sole carbon resource, leading to no sulfate reduction and Ni2+ removal. However, after the addition of citrate, SRB grew well, and sulfate was quickly reduced to sulfide. Simultaneously, the Ni-citrate complex was biodegraded to Ni2+ and acetate. The NiS precipitate was then formed, and Ni2+ was completely removed from the solution. It was suggested that the addition of citrate greatly alleviates Ni2+ toxicity to SRB and improves the removal of Ni2+, which was confirmed by quantitative real-time PCR targeting dissimilatory sulfite reductase (dsrAB) genes. Analysis of the carbon metabolism indicated that lactate instead of acetate served as the electron donor for sulfate reduction. This study offers a potential approach to increase the removal of heavy metals from wastewater in the single stage SRB-based bioprocess. PMID:25860948

  12. Spore-Forming Thermophilic Sulfate-Reducing Bacteria Isolated from North Sea Oil Field Waters

    PubMed Central

    Rosnes, Jan Thomas; Torsvik, Terje; Lien, Torleiv

    1991-01-01

    Thermophilic sulfate-reducing bacteria were isolated from oil field waters from oil production platforms in the Norwegian sector of the North Sea. Spore-forming rods dominated in the enrichments when lactate, propionate, butyrate, or a mixture of aliphatic fatty acids (C4 through C6) was added as a carbon source and electron donor. Representative strains were isolated and characterized. The isolates grew autotrophically on H2-CO2 and heterotrophically on fatty acids such as formate, propionate, butyrate, caproate, valerate, pyruvate, and lactate and on alcohols such as methanol, ethanol, and propanol. Sulfate, sulfite, and thiosulfate but not nitrate could be used as an electron acceptor. The temperature range for growth was 43 to 78°C; the spores were extremely heat resistant and survived 131°C for 20 min. The optimum pH was 7.0. The isolates grew well in salt concentrations ranging from 0 to 800 mmol of NaCl per liter. Sulfite reductase P582 was present, but cytochrome c and desulfoviridin were not found. Electron micrographs revealed a gram-positive cell organization. The isolates were classified as a Desulfotomaculum sp. on the basis of spore formation, general physiological characteristics, and submicroscopic organization. To detect thermophilic spore-forming sulfate-reducing bacteria in oil field water, polyvalent antisera raised against antigens from two isolates were used. These bacteria were shown to be widespread in oil field water from different platforms. The origin of thermophilic sulfate-reducing bacteria in the pore water of oil reservoirs is discussed. Images PMID:16348538

  13. Sulfate- and Sulfur-Reducing Bacteria as Terrestrial Analogs for Microbial Life on Jupiter's Satellite Io

    NASA Technical Reports Server (NTRS)

    Pikuta, Elena V.; Hoover, Richard B.; Six, N. Frank (Technical Monitor)

    2001-01-01

    Observations from the Voyager and Galileo spacecraft have revealed Jupiter's moon Io to be the most volcanically active body of our Solar System. The Galileo Near Infrared Imaging Spectrometer (NIMS) detected extensive deposits of sulfur compounds, elemental sulfur and SO2 frost on the surface of Io. There are extreme temperature variations on Io's surface, ranging from -130 C to over 2000 C at the Pillan Patera volcanic vent. The active volcanoes, fumaroles, calderas, and lava lakes and vast sulfur deposits on this frozen moon indicate that analogs of sulfur- and sulfate-reducing bacteria might inhabit Io. Hence Io may have great significance to Astrobiology. Earth's life forms that depend on sulfur respiration are members of two domains: Bacteria and Archaea. Two basic links of the biogeochemical sulfur cycle of Earth have been studied: 1) the sulfur oxidizing process (occurring at aerobic conditions) and 2) the process of sulfur-reduction to hydrogen sulfide (anaerobic conditions). Sulfate-reducing bacteria (StRB) and sulfur-reducing bacteria (SrRB) are responsible for anaerobic reducing processes. At the present time the systematics of StRB include over 112 species distributed into 35 genera of Bacteria and Archaea. Moderately thermophilic and mesophilic SrRB belong to the Bacteria. The hyperthermophilic SrRB predominately belong to the domain Archaea and are included in the genera: Pyrodictium, Thermoproteus, Pyrobaculum, Thermophilum, Desulfurococcus, and Thermodiscus. The StRB and SrRB use a wide spectrum of substrates as electron donors for lithotrophic and heterotrophic type nutrition. The electron acceptors for the StRB include: sulfate, thiosulfate, sulfite, sulfur, arsenate, dithionite, tetrathionate, sulfur monoxide, iron, nitrite, selenite, fumarate, oxygen, carbon dioxide, and chlorine-containing phenol compounds. The Sulfate- and Sulfur-reducing bacteria are widely distributed in anaerobic ecosystems, including extreme environments like hot springs

  14. Molecular characterization of sulfate-reducing bacteria in the Guaymas Basin

    NASA Technical Reports Server (NTRS)

    Dhillon, Ashita; Teske, Andreas; Dillon, Jesse; Stahl, David A.; Sogin, Mitchell L.

    2003-01-01

    The Guaymas Basin (Gulf of California) is a hydrothermal vent site where thermal alteration of deposited planktonic and terrestrial organic matter forms petroliferous material which supports diverse sulfate-reducing bacteria. We explored the phylogenetic and functional diversity of the sulfate-reducing bacteria by characterizing PCR-amplified dissimilatory sulfite reductase (dsrAB) and 16S rRNA genes from the upper 4 cm of the Guaymas sediment. The dsrAB sequences revealed that there was a major clade closely related to the acetate-oxidizing delta-proteobacterial genus Desulfobacter and a clade of novel, deeply branching dsr sequences related to environmental dsr sequences from marine sediments in Aarhus Bay and Kysing Fjord (Denmark). Other dsr clones were affiliated with gram-positive thermophilic sulfate reducers (genus Desulfotomaculum) and the delta-proteobacterial species Desulforhabdus amnigena and Thermodesulforhabdus norvegica. Phylogenetic analysis of 16S rRNAs from the same environmental samples resulted in identification of four clones affiliated with Desulfobacterium niacini, a member of the acetate-oxidizing, nutritionally versatile genus Desulfobacterium, and one clone related to Desulfobacula toluolica and Desulfotignum balticum. Other bacterial 16S rRNA bacterial phylotypes were represented by non-sulfate reducers and uncultured lineages with unknown physiology, like OP9, OP8, as well as a group with no clear affiliation. In summary, analyses of both 16S rRNA and dsrAB clone libraries resulted in identification of members of the Desulfobacteriales in the Guaymas sediments. In addition, the dsrAB sequencing approach revealed a novel group of sulfate-reducing prokaryotes that could not be identified by 16S rRNA sequencing.

  15. A cultured greigite-producing magnetotactic bacterium in a novel group of sulfate-reducing bacteria.

    PubMed

    Lefèvre, Christopher T; Menguy, Nicolas; Abreu, Fernanda; Lins, Ulysses; Pósfai, Mihály; Prozorov, Tanya; Pignol, David; Frankel, Richard B; Bazylinski, Dennis A

    2011-12-23

    Magnetotactic bacteria contain magnetosomes--intracellular, membrane-bounded, magnetic nanocrystals of magnetite (Fe(3)O(4)) or greigite (Fe(3)S(4))--that cause the bacteria to swim along geomagnetic field lines. We isolated a greigite-producing magnetotactic bacterium from a brackish spring in Death Valley National Park, California, USA, strain BW-1, that is able to biomineralize greigite and magnetite depending on culture conditions. A phylogenetic comparison of BW-1 and similar uncultured greigite- and/or magnetite-producing magnetotactic bacteria from freshwater to hypersaline habitats shows that these organisms represent a previously unknown group of sulfate-reducing bacteria in the Deltaproteobacteria. Genomic analysis of BW-1 reveals the presence of two different magnetosome gene clusters, suggesting that one may be responsible for greigite biomineralization and the other for magnetite. PMID:22194580

  16. Effects of sulfate-reducing bacteria on methylmercury at the sediment-water interface.

    PubMed

    Zeng, Lingxia; Luo, Guangjun; He, Tianrong; Guo, Yanna; Qian, Xiaoli

    2016-08-01

    Sediment cores (containing sediment and overlying water) from Baihua Reservoir (SW China) were cultured under different redox conditions with different microbial activities, to understand the effects of sulfate-reducing bacteria (SRB) on mercury (Hg) methylation at sediment-water interfaces. Concentrations of dissolved methyl mercury (DMeHg) in the overlying water of the control cores with bioactivity maintained (BAC) and cores with only sulfate-reducing bacteria inhibited (SRBI) and bacteria fully inhibited (BACI) were measured at the anaerobic stage followed by the aerobic stage. For the BAC and SRBI cores, DMeHg concentrations in waters were much higher at the anaerobic stage than those at the aerobic stage, and they were negatively correlated to the dissolved oxygen concentrations (r=-0.5311 and r=-0.4977 for BAC and SRBI, respectively). The water DMeHg concentrations of the SRBI cores were 50% lower than those of the BAC cores, indicating that the SRB is of great importance in Hg methylation in sediment-water systems, but there should be other microbes such as iron-reducing bacteria and those containing specific gene cluster (hgcAB), besides SRB, causing Hg methylation in the sediment-water system. PMID:27521953

  17. Influence of sulfate-reducing bacteria on alloy 625 and austenitic stainless steel weldments

    SciTech Connect

    Enos, D.G.; Taylor, S.R.

    1996-11-01

    A series of welded austenitic stainless steel and alloy 625 clad specimens were exposed to natural lake water inoculated with a mixed culture of anaerobic organisms high in sulfate-reducing bacteria. Total exposure was 300 days. The water and bacteria were taken from an actual service water system. Electrochemical testing included electrochemical impedance spectroscopy, monitoring of open-circuit potential (E{sub oc}), and zero resistance ammetry tests. Comparison of electrochemical and visual observations to sterile controls indicated electrochemical behavior of all materials in the test matrix was influenced by the bacteria. Polarization resistance and E{sub oc} values were reduced dramatically. Attack was along the fusion line of the weld. The magnitude of these effects followed a trend predicted by the pitting index for each material.

  18. Kinetics of sulfate and hydrogen uptake by the thermophilic sulfate-reducing bacteria Thermodesulfobacterium sp. strain JSP and Thermodesulfovibrio sp. strain R1Ha3

    SciTech Connect

    Sonne-Hansen, J.; Ahring, B.K.; Westermann, P.

    1999-03-01

    Dissimilatory sulfate reduction and methanogenesis are the main terminal processes in the anaerobic food chain. Both the sulfate-reducing bacteria (SRB) and the methane-producing archaea (MPA) use acetate and hydrogen as substrates and, therefore, compete for common electron donors in sulfate-containing natural environments. Due to a higher affinity for the electron donors acetate and hydrogen, SRB outcompete MPA for these compounds whenever sulfate is present in sufficient concentrations. Half-saturation constants (K{sub m}), maximum uptake rates (V{sub max}), and threshold concentrations for sulfate and hydrogen were determined for two thermophilic sulfate-reducing bacteria (SRB) in an incubation system without headspace. K{sub m} values determined for the thermophilic SRB were similar to the constants described for mesophilic SRB isolated from environments with low sulfate concentrations.

  19. Isolation of Sulfate-Reducing Bacteria from Sediments Above the Deep-Subseafloor Aquifer

    PubMed Central

    Fichtel, Katja; Mathes, Falko; Könneke, Martin; Cypionka, Heribert; Engelen, Bert

    2011-01-01

    On a global scale, crustal fluids fuel a large part of the deep-subseafloor biosphere by providing electron acceptors for microbial respiration. In this study, we examined bacterial cultures from sediments of the Juan de Fuca Ridge, Northeast Pacific (IODP Site U1301). The sediments comprise three distinctive compartments: an upper sulfate-containing zone, formed by bottom-seawater diffusion, a sulfate-depleted zone, and a second (∼140 m thick) sulfate-containing zone influenced by fluid diffusion from the basaltic aquifer. In order to identify and characterize sulfate-reducing bacteria, enrichment cultures from different sediment layers were set up, analyzed by molecular screening, and used for isolating pure cultures. The initial enrichments harbored specific communities of heterotrophic microorganisms. Strains affiliated to Desulfosporosinus lacus, Desulfotomaculum sp., and Desulfovibrio aespoeensis were isolated only from the top layers (1.3–9.1 meters below seafloor, mbsf), while several strains of Desulfovibrio indonesiensis and a relative of Desulfotignum balticum were obtained from near-basement sediments (240–262 mbsf). Physiological tests on three selected strains affiliated to Dv. aespoeensis, Dv. indonesiensis, and Desulfotignum balticum indicated that all reduce sulfate with a limited number of short-chain n-alcohols or fatty acids and were able to ferment either ethanol, pyruvate, or betaine. All three isolates shared the capacity of growing chemolithotrophically with H2 as sole electron donor. Strain P23, affiliating with Dv. indonesiensis, even grew autotrophically in the absence of any organic compounds. Thus, H2 might be an essential electron donor in the deep-subseafloor where the availability of organic substrates is limited. The isolation of non-sporeforming sulfate reducers from fluid-influenced layers indicates that they have survived the long-term burial as active populations even after the separation from the seafloor hundreds

  20. Inhibition of sulfate reducing bacteria in aquifer sediment by iron nanoparticles.

    PubMed

    Kumar, Naresh; Omoregie, Enoma O; Rose, Jerome; Masion, Armand; Lloyd, Jonathan R; Diels, Ludo; Bastiaens, Leen

    2014-03-15

    Batch microcosms were setup to determine the impact of different sized zero valent iron (Fe(0)) particles on microbial sulfate reduction during the in situ bio-precipitation of metals. The microcosms were constructed with aquifer sediment and groundwater from a low pH (3.1), heavy-metal contaminated aquifer. Nano (nFe(0)), micro (mFe(0)) and granular (gFe(0)) sized Fe(0) particles were added to separate microcosms. Additionally, selected microcosms were also amended with glycerol as a C-source for sulfate-reducing bacteria. In addition to metal removal, Fe(0) in microcosms also raised the pH from 3.1 to 6.5, and decreased the oxidation redox potential from initial values of 249 to -226 mV, providing more favorable conditions for microbial sulfate reduction. mFe(0) and gFe(0) in combination with glycerol were found to enhance microbial sulfate reduction. However, no sulfate reduction occurred in the controls without Fe(0) or in the microcosm amended with nFe(0). A separate dose test confirmed the inhibition for sulfate reduction in presence of nFe(0). Hydrogen produced by Fe(0) was not capable of supporting microbial sulfate reduction as a lone electron donor in this study. Microbial analysis revealed that the addition of Fe(0) and glycerol shifted the microbial community towards Desulfosporosinus sp. from a population initially dominated by low pH and metal-resisting Acidithiobacillus ferrooxidans. PMID:24388832

  1. Identification and distribution of sulfate reducing bacteria and sulphur-oxidising bacteria in northern South China Sea

    NASA Astrophysics Data System (ADS)

    Mao, S.; Zhu, X.; Guan, H.; Wu, D.; Wu, N.

    2015-12-01

    Fatty acids are one of the major components in modern marine sediments. It is well known that the saturated short-chain FAs were typically to be from vascular plants, algae, bacteria, and other sources, while the saturated long-chain FAs are the major components found in leaf waxes, suberin, and cutin in terrestrial higher plants. So the lipid biomarkers of fatty acids in Site 4B from Shenhu Area, northern South China Sea were investigated in Recent research supported from the 973 Program (2009CB219506), and the resources of branched fatty acids and monounsaturated fatty acids were mainly discussed. The results reveal that i/a15:0, i/a17:0, 16:1ω5, 18:1ω9 and 10me16:0 are derived from sulfate reducing bacteria (SRB), while 16:1ω7t/c and 18:1ω7 are originated from sulphur-oxidising bacteria (SOB). The biomakers of methanotrophs such as 16:1ω6/8 and 18:1ω6/8 were not detected in the sediments which coincide with more positive carbon isotope values of the fatty acids in the sediments. The stable relationship between SRB and SOB below 97cm in the sediments reflects the relative stable oxidative and reductive depositional environment which may be connected with the sulphur cycle in the sediments, that is carried out as sulfate is reduced to sulfide, and then sulfide is oxidized to sulfate and elemental sulfur, at last elemental sulfur is disproportionated to sulfide and sulfate. The frequently changed relationship of SRB and SOB above 97cm in the sediments indicates intensely changing oxidative and reductive sedimental environment, that may related with diapir structure around Site 4B, which also brings about hydrocarbon seepage leading to increasing biomass at 97cm.

  2. Preparation of metal-resistant immobilized sulfate reducing bacteria beads for acid mine drainage treatment.

    PubMed

    Zhang, Mingliang; Wang, Haixia; Han, Xuemei

    2016-07-01

    Novel immobilized sulfate-reducing bacteria (SRB) beads were prepared for the treatment of synthetic acid mine drainage (AMD) containing high concentrations of Fe, Cu, Cd and Zn using up-flow anaerobic packed-bed bioreactor. The tolerance of immobilized SRB beads to heavy metals was significantly enhanced compared with that of suspended SRB. High removal efficiencies of sulfate (61-88%) and heavy metals (>99.9%) as well as slightly alkaline effluent pH (7.3-7.8) were achieved when the bioreactor was fed with acidic influent (pH 2.7) containing high concentrations of multiple metals (Fe 469 mg/L, Cu 88 mg/L, Cd 92 mg/L and Zn 128 mg/L), which showed that the bioreactor filled with immobilized SRB beads had tolerance to AMD containing high concentrations of heavy metals. Partially decomposed maize straw was a carbon source and stabilizing agent in the initial phase of bioreactor operation but later had to be supplemented by a soluble carbon source such as sodium lactate. The microbial community in the bioreactor was characterized by denaturing gradient gel electrophoresis (DGGE) and sequencing of partial 16S rDNA genes. Synergistic interaction between SRB (Desulfovibrio desulfuricans) and co-existing fermentative bacteria could be the key factor for the utilization of complex organic substrate (maize straw) as carbon and nutrients source for sulfate reduction. PMID:27058913

  3. Hydrogen sulfide production by sulfate-reducing bacteria utilizing additives eluted from plastic resins.

    PubMed

    Tsuchida, Daisuke; Kajihara, Yusuke; Shimidzu, Nobuhiro; Hamamura, Kengo; Nagase, Makoto

    2011-06-01

    In the present study it was demonstrated that organic additives eluted from plastic resins could be utilized as substrates by sulfate-reducing bacteria. Two laboratory-scale experiments, a microcosm experiment and a leaching experiment, were conducted using polyvinyl chloride (PVC) as a model plastic resin. In the former experiment, the conversion of sulfate to sulfide was evident in microcosms that received plasticized PVC as the sole carbon source, but not in those that received PVC homopolymer. Additionally, dissolved organic carbon accumulated only in microcosms that received plasticized PVC, indicating that the dissolved organic carbon originated from additives. In the leaching experiment, phenol and bisphenol A were found in the leached solutions. These results suggest that the disposal of waste plastics in inert waste landfills may result in the production of H(2)S. PMID:21135024

  4. Microbial control of the production of hydrogen sulfide by sulfate-reducing bacteria.

    PubMed

    Montgomery, A D; McLnerney, M J; Sublette, K L

    1990-03-01

    A sulfide-resistant ctrain of Thiobacillus denitrificans, strain F, prevented the accumulation of sulfide by Desulfovibrio desulfuricans when both organisms were grown in liquid medium or in Berea sandstone cores. The wild-type strain of T. denitrificans did not prevent the accumulation of sulfide produced by D. desulfuricans. Strain F also prevented the accumulation of sulfide by a mixed population of sulfate-reducing bacteria enriched from an oil field brine. Fermentation balances showed that strain F stoichiometrically oxidized the sulfide produced by D. desulfuricans and the oil field brine enrichment to sulfate. These data suggest that strain F would be effective in controlling sulfide production in oil reservoirs and other environments. PMID:18592547

  5. Genes for Uranium Bioremediation in the Anaerobic Sulfate-Reducing Bacteria

    SciTech Connect

    Wall, Judy D.

    1999-06-01

    Objective A: Electron transfer components necessary for uranium reduction. Objective B: Possible FNR-analog in the sulfate-reducing bacteria. Attempts to isolate FNR or FIKJ analogs from Desuflovibrio through the design of degenerate primers for amplification of portions of the genes has not been successful. In contrast, several amplicons have been generated for the genes encoding the regulators of two-component signal sequences. Since several global regulators fall into this class, we are attempting to obtain sufficient sequence information to indicate what metabolic pathways are affected by the regulators. Cloning and sequencing of two such amplicons has revealed that bona fide two-component regulators are present in Desulfovibrio.

  6. Genes for Uranium Bioremediation in the Anaerobic Sulfate-Reducing Bacteria

    SciTech Connect

    Wall, Judy D.

    2001-06-01

    The objectives of the previous grant period were designed to explore the electron transport pathway employed by the sulfate-reducing bacteria (SRB) for the reduction of U(VI) to U(IV). More specifically experiments were designed to determine whether U(VI) reduction by members of the genus Desulfovibrio was mediated by a unique, dedicated reductase or occurred as a fortuitous reaction with a reductase naturally involved in alternative reduction processes. In addition, the regulation of the hierarchical expression of terminal electron acceptors (reductases) in the SRB was to be examined.

  7. Immobilizing U from solution by immobilized sulfate-reducing bacteria of desulfovibrio desulfuricans

    NASA Astrophysics Data System (ADS)

    Xu, Hulfang; Barton, Larry L.

    2000-07-01

    As determined by transmission electron microscopy, the reduction of uranyl accetate by immobilized cells of Desulfovibrio desulfuricans results in the production of black uraninite nanocrystals precipitated outside the cell. Some nanocrystals are associated with outer membranes of the cell as revealed from cross sections of these metabolically active sulfate-reducing bacteria. The nanocrystals have an average diameter of 5 nm and have anhedral shape. It is proposed that cytochrome in these cells has an important role in the reduction of uranyl through transferring electron from molecular hydrogen or lactic acid to uranyl ions.

  8. The role of DOM in the methylation of mercury by sulfate-reducing bacteria

    NASA Astrophysics Data System (ADS)

    Aiken, G.; Gerbig, C. A.; Krabbenhoft, D. P.; Moreau, J. W.

    2011-12-01

    Methylation of mercury (Hg) by sulfate-reducing bacteria is an ecologically important, but poorly understood aspect of mercury cycling in aquatic systems. Dissolved organic matter (DOM) has long been thought to play a role in the methylation process, but little is known about the nature of these interactions. We designed two experimental approaches to better define the effects of DOM on mercury methylation by sulfate-reducing bacteria. The first approach was to determine directly the effects of DOM isolates on mercury methylation by Desulfobulbus propionicus, a known strain of sulfate reducing bacteria. These experiments employed stable isotope tracers of Hg and several different DOM isolates. Results indicated that the addition of DOM substantially increased the production of methylmercury (MeHg), however, the individual DOM isolates influenced MeHg production rates differently. In addition, spiked Hg equilibrated with DOM for a longer time period (5 or 30 days) was more readily methylated than spiked Hg equilibrated for only 4 hours. The second approach attempted to address the chemistry involved with the DOM-Hg-S interactions under similar conditions to those used in the methylation experiments. A method was developed employing C18 chromatography and extended X-ray absorption fine structure (EXAFS) spectroscopy to examine local mercury binding environments for solutions containing DOM isolates and varying sulfide and Hg concentrations. Systems with different DOM isolates showed different sulfur coordination numbers, but the Hg-S bond distances were consistently indicative of a metacinnabar-like nanocolloid. These results suggest that nanocolloidal metacinnabar-like species are stabilized by interactions with DOM and these nanocolloids become less ordered and presumably smaller with decreasing Hg:DOM ratio and decreasing sulfide concentrations. Together, the results of these two experimental approaches are consistent with a conceptual model wherein DOM interacts

  9. Fractionation of Hydrogen Isotopes by Sulfate- and Nitrate-Reducing Bacteria

    PubMed Central

    Osburn, Magdalena R.; Dawson, Katherine S.; Fogel, Marilyn L.; Sessions, Alex L.

    2016-01-01

    Hydrogen atoms from water and food are incorporated into biomass during cellular metabolism and biosynthesis, fractionating the isotopes of hydrogen—protium and deuterium—that are recorded in biomolecules. While these fractionations are often relatively constant in plants, large variations in the magnitude of fractionation are observed for many heterotrophic microbes utilizing different central metabolic pathways. The correlation between metabolism and lipid δ2H provides a potential basis for reconstructing environmental and ecological parameters, but the calibration dataset has thus far been limited mainly to aerobes. Here we report on the hydrogen isotopic fractionations of lipids produced by nitrate-respiring and sulfate-reducing bacteria. We observe only small differences in fractionation between oxygen- and nitrate-respiring growth conditions, with a typical pattern of variation between substrates that is broadly consistent with previously described trends. In contrast, fractionation by sulfate-reducing bacteria does not vary significantly between different substrates, even when autotrophic and heterotrophic growth conditions are compared. This result is in marked contrast to previously published observations and has significant implications for the interpretation of environmental hydrogen isotope data. We evaluate these trends in light of metabolic gene content of each strain, growth rate, and potential flux and reservoir-size effects of cellular hydrogen, but find no single variable that can account for the differences between nitrate- and sulfate-respiring bacteria. The emerging picture of bacterial hydrogen isotope fractionation is therefore more complex than the simple correspondence between δ2H and metabolic pathway previously understood from aerobes. Despite the complexity, the large signals and rich variability of observed lipid δ2H suggest much potential as an environmental recorder of metabolism. PMID:27531993

  10. D/H fractionation in lipids of facultative and obligate denitrifying and sulfate reducing bacteria

    NASA Astrophysics Data System (ADS)

    Osburn, M. R.; Sessions, A. L.

    2012-12-01

    The hydrogen isotopic composition of lipids has been shown to vary broadly in both cultured bacteria and in environmental samples. Culturing studies have indicated that this variability may primarily reflect metabolism; however, the limited number of organisms studied thus far prevents application of these trends to interpretation of environmental samples. Here we report D/H fractionations in anaerobic bacteria, including both facultative and obligate anaerobic organisms with a range of electron donors, acceptors, and metabolic pathways. Experiments using the metabolically flexible alphaproteobacterium Paracoccus denitrificans probe particular central metabolic pathways using a range of terminal electron acceptors. While a large range of δD values has been observed during aerobic metabolism, denitrifying cultures produce a more limited range in δD values that are more similar to each other than the corresponding aerobic culture. Data from the sulfate reducing bacteria Desulfobacterium autotrophicum and Desulfobacter hydrogenophilus indicate that chemolithoautotrophy and anaerobic heterotrophy can produce similar δD values, and are similar between bacteria despite differing metabolic pathways. These results suggest that the fractionation of D/H depends both on the specific metabolic pathway and the electron acceptor. While this is not inconsistent with previous studies, it suggests the simple correspondence between δD and metabolism previously understood from aerobic bacteria is not universally applicable.

  11. Sulfate-reducing bacteria are common members of bacterial communities in Altamira Cave (Spain).

    PubMed

    Portillo, M Carmen; Gonzalez, Juan M

    2009-01-15

    The conservation of paleolithic paintings such as those in Altamira Cave (Spain) is a primary objective. Recent molecular studies have shown the existence of unknown microbial communities in this cave including anaerobic microorganisms on cave walls. Herein, we analyzed an anaerobic microbial group, the sulfate-reducing bacteria (SRB), from Altamira Cave with potential negative effects on painting conservation. In the present work, the communities of bacteria and SRB were studied through PCR-DGGE analysis. Data suggest that SRB communities represent a significant, highly diverse bacterial group in Altamira Cave. These findings represent a first report on this physiological group on caves with paleolithic paintings and their potential biodegradation consequences. Expanding our knowledge on microbial communities in Altamira Cave is a priority to design appropriate conservation strategies. PMID:19027143

  12. Effects of iron-reducing bacteria on carbon steel corrosion induced by thermophilic sulfate-reducing consortia.

    PubMed

    Valencia-Cantero, Eduardo; Peña-Cabriales, Juan José

    2014-02-28

    Four thermophilic bacterial species, including the iron-reducing bacterium Geobacillus sp. G2 and the sulfate-reducing bacterium Desulfotomaculum sp. SRB-M, were employed to integrate a bacterial consortium. A second consortium was integrated with the same bacteria, except for Geobacillus sp. G2. Carbon steel coupons were subjected to batch cultures of both consortia. The corrosion induced by the complete consortium was 10 times higher than that induced by the second consortium, and the ferrous ion concentration was consistently higher in iron-reducing consortia. Scanning electronic microscopy analysis of the carbon steel surface showed mineral films colonized by bacteria. The complete consortium caused profuse fracturing of the mineral film, whereas the non-iron-reducing consortium did not generate fractures. These data show that the iron-reducing activity of Geobacillus sp. G2 promotes fracturing of mineral films, thereby increasing steel corrosion. PMID:24225375

  13. Genetics and molecular biology of hydrogen metabolism in sulfate reducing bacteria

    SciTech Connect

    Wall, J.D.

    1990-01-01

    The work proposed to be accomplished in the previous funding period was to develop a procedure for genetic exchange based on conjugation mediated by broad host-range plasmids. Such a system has recently been identified that employs IncQ group plasmids and a Desulfovibrio desulfuricans G100A derivative as recipient. During the search for conjugation, we also identified a defective bacteriophage capable of generalized transduction of fragments of chromosomal DNA between mutants of Desulfovibrio desulfuricans. Some of the factors influencing the production and transduction by this defective phage have been investigated. A curious observation was made concerning the response of colonies of these sulfate-reducing bacteria upon exposure to air. All the cells of a colony do not die. Some survive, most likely by producing sulfide at a rate sufficient to provide an anaerobic environment. Dramatic colony morphological changes occur and these have been documented by scanning and transmission electron microscopy. Finally a small endogenous plasmid has been isolated from Desulfovibrio desulfuricans G100A. It has been stably subcloned into a sequencing vector, and nested deletions of this plasmid are being prepared. This plasmid may be useful for the development of a shuttle cloning vector that could be used in more diverse Desulfovibrio. Many of the techniques now to be used in the mutant analysis of hydrogenase genes in the sulfate-reducing bacteria have been successfully applied in an analysis of hydrogenase functions of Rhodobacter capsulatus. 8 figs., 2 tabs.

  14. Understanding the performance of sulfate reducing bacteria based packed bed reactor by growth kinetics study and microbial profiling.

    PubMed

    Dev, Subhabrata; Roy, Shantonu; Bhattacharya, Jayanta

    2016-07-15

    A novel marine waste extract (MWE) as alternative nitrogen source was explored for the growth of sulfate reducing bacteria (SRB). Variation of sulfate and nitrogen (MWE) showed that SRB growth follows an uncompetitive inhibition model. The maximum specific growth rates (μmax) of 0.085 and 0.124 h(-1) and inhibition constants (Ki) of 56 and 4.6 g/L were observed under optimized sulfate and MWE concentrations, respectively. The kinetic data shows that MWE improves the microbial growth by 27%. The packed bed bioreactor (PBR) under optimized sulfate and MWE regime showed sulfate removal efficiency of 62-66% and metals removal efficiency of 66-75% on using mine wastewater. The microbial community analysis using DGGE showed dominance of SRB (87-89%). The study indicated the optimum dosing of sulfate and cheap organic nitrogen to promote the growth of SRB over other bacteria. PMID:27085153

  15. Styrene N-vinylpyrrolidone metal-nanocomposites as antibacterial coatings against Sulfate Reducing Bacteria.

    PubMed

    Fathy, M; Badawi, A; Mazrouaa, A M; Mansour, N A; Ghazy, E A; Elsabee, M Z

    2013-10-01

    Copolymer of styrene, and vinylpyrrolidone was prepared by various techniques. Different nanometals and nanometal oxides were added into the copolymer as antimicrobial agents against Sulfate Reducing Bacteria (SRB). The nanocomposite chemical structure was confirmed by using FTIR, (1)H NMR spectroscopy and thermogravimetric analysis (TGA). The biocidal action of these nanocomposites against the SRB was detected using sulfide determination method in Postgate medium B. The data indicated that the nanocomposites had an inhibitory effect on the growth of SRB and reduced the bacterial corrosion rate of mild steel coupons. The prepared nanocomposites have high inhibition efficiency when applied as coatings and show less efficiency when applied as solids or solution into SRB medium. The copolymer and its nanocomposites effectively reduced the total corrosion rate as determined by total weight loss method. PMID:23910315

  16. Activity and kinetic properties of phosphotransacetylase from intestinal sulfate-reducing bacteria.

    PubMed

    Kushkevych, Ivan V

    2015-01-01

    Phosphotransacetylase activity and the kinetic properties of the enzyme from intestinal sulfate-reducing bacteria Desulfovibrio piger and Desulfomicrobium sp. has never been well-characterized and has not been studied yet. In this paper, the specific activity of phosphotransacetylase and the kinetic properties of the enzyme in cell-free extracts of both D. piger Vib-7 and Desulfomicrobium sp. Rod-9 intestinal bacterial strains were presented at the first time. The microbiological, biochemical, biophysical and statistical methods in this work were used. The optimal temperature and pH for enzyme reaction was determined. Analysis of the kinetic properties of the studied enzyme was carried out. Initial (instantaneous) reaction velocity (V0), maximum amount of the product of reaction (Pmax), the reaction time (half saturation period, τ) and maximum velocity of the phosphotransacetylase reaction (Vmax) were defined. Michaelis constants (Km) of the enzyme reaction (3.36 ± 0.35 mM for D. piger Vib-7, 5.97 ± 0.62 mM for Desulfomicrobium sp. Rod-9) were calculated. The studies of the phosphotransacetylase in the process of dissimilatory sulfate reduction and kinetic properties of this enzyme in intestinal sulfate-reducing bacteria, their production of acetate in detail can be perspective for clarification of their etiological role in the development of the humans and animals bowel diseases. These studies might help in predicting the development of diseases of the gastrointestinal tract, by providing further details on the etiology of bowel diseases which are very important for the clinical diagnosis of these disease types. PMID:25781158

  17. PHYLOGENETIC TREE OF 16S RIBOSOMAL RNA SEQUENCES FROM SULFATE-REDUCING BACTERIA IN A SANDY MARINE ENVIRONMENT

    EPA Science Inventory

    Phylogenetic divergence among sulfate-reducing bacteria in an estuarine sediment sample was investigated by PCR amplification and comparison of partial 16S rDNA sequences. wenty unique 16S RDNA sequences were found, 12 from delta subclass bacteria based on overall sequence simila...

  18. Sulfate reducing bacteria and their activities in oil sands process-affected water biofilm.

    PubMed

    Liu, Hong; Yu, Tong; Liu, Yang

    2015-12-01

    Biofilm reactors were constructed to grow stratified multispecies biofilm in oil sands process-affected water (OSPW) supplemented with growth medium. The development of sulfate reducing bacteria (SRB) within the biofilm and the biofilm treatment of OSPW were evaluated. The community structure and potential activity of SRB in the biofilm were investigated with H2S microsensor measurements, dsrB gene-based denaturing gradient gel electrophoresis (DGGE), and the real time quantitative polymerase chain reaction (qPCR). Multispecies biofilm with a thickness of 1000 μm was successfully developed on engineered biocarriers. H2S production was observed in the deeper anoxic zone of the biofilm from around 750 μm to 1000 μm below the bulk water-biofilm interface, revealing sulfate reduction in the deeper zone of the stratified biofilm. The biofilm removed chemical oxygen demand (COD), sulfate, and nitrogen. The study expands current knowledge of biofilm treatment of OSPW and the function of anaerobic SRB in OSPW biofilm, and thus provides information for future bioreactor development in the reclamation of OSPW. PMID:26204047

  19. Leaching of 226Ra from U mill tailings by sulfate-reducing bacteria.

    PubMed

    Landa, E R; Miller, C L; Updegraff, D M

    1986-10-01

    Relatively insoluble sulfate precipitates appear to be a major host for Ra in sulfuric acid-treated, U mill tailings. The dissolution of such precipitates by natural processes, such as metabolism by sulfate-reducing bacteria (SRB), creates the potential for release of Ra to contacting waters. Significant leaching of Ra by SRB was achieved in the laboratory during the anaerobic incubation (1 to 119 days) of U mill tailings with pure cultures of Desulfovibrio desulfuricans and mixed cultures containing SRB isolated from the tailings, all grown on a lactate medium at room temperature. While the maximum 226Ra concentration reached in a sterile media control was 0.44 Bq/L (12 pCi/L), that in the SRB systems was 61 Bq/L (1640 pCi/L) or about 20% of the total Ra inventory in the original tailings sample. The leaching of Ra in SRB systems was accompanied by a decrease in soluble sulfate concentration, an increase in total sulfide concentration, and an increase in the number of SRB. The observed leaching effect does not appear to be due to the action of microbial chelates or to binding to cell walls. Potential implications of these findings to the management of U mill tailings and other radioactive wastes are discussed. PMID:3759464

  20. Leaching of /sup 226/Ra from U mill tailings by sulfate-reducing bacteria

    SciTech Connect

    Landa, E.R.; Miller, C.L.; Updegraff, D.M.

    1986-10-01

    Relatively insoluble sulfate precipitates appear to be a major host for Ra in sulfuric acid-treated, U mill tailings. The dissolution of such precipitates by natural processes, such as metabolism by sulfate-reducing bacteria (SRB), creates the potential for release of Ra to contacting waters. Significant leaching of Ra by SRB was achieved in the laboratory during the anaerobic incubation (1 to 119 days) of U mill tailings with pure cultures of Desulfovibrio desulfuricans and mixed cultures containing SRB isolated from the tailings, all grown on a lactate medium at room temperature. While the maximum /sup 226/Ra concentration reached in a sterile media control was 0.44 Bq/L (12 pCi/L), that in the SRB systems was 61 Bq/L (1640 pCi/L) or about 20% of the total Ra inventory in the original tailings sample. The leaching of Ra in SRB systems was accompanied by a decrease in soluble sulfate concentration, an increase in total sulfide concentration, and an increase in the number of SRB. The observed leaching effect does not appear to be due to the action of microbial chelates or to binding to cell walls. Potential implications of these findings to the management of U mill tailings and other radioactive wastes are discussed.

  1. Corrosion of Iron by Sulfate-Reducing Bacteria: New Views of an Old Problem

    PubMed Central

    Garrelfs, Julia

    2014-01-01

    About a century ago, researchers first recognized a connection between the activity of environmental microorganisms and cases of anaerobic iron corrosion. Since then, such microbially influenced corrosion (MIC) has gained prominence and its technical and economic implications are now widely recognized. Under anoxic conditions (e.g., in oil and gas pipelines), sulfate-reducing bacteria (SRB) are commonly considered the main culprits of MIC. This perception largely stems from three recurrent observations. First, anoxic sulfate-rich environments (e.g., anoxic seawater) are particularly corrosive. Second, SRB and their characteristic corrosion product iron sulfide are ubiquitously associated with anaerobic corrosion damage, and third, no other physiological group produces comparably severe corrosion damage in laboratory-grown pure cultures. However, there remain many open questions as to the underlying mechanisms and their relative contributions to corrosion. On the one hand, SRB damage iron constructions indirectly through a corrosive chemical agent, hydrogen sulfide, formed by the organisms as a dissimilatory product from sulfate reduction with organic compounds or hydrogen (“chemical microbially influenced corrosion”; CMIC). On the other hand, certain SRB can also attack iron via withdrawal of electrons (“electrical microbially influenced corrosion”; EMIC), viz., directly by metabolic coupling. Corrosion of iron by SRB is typically associated with the formation of iron sulfides (FeS) which, paradoxically, may reduce corrosion in some cases while they increase it in others. This brief review traces the historical twists in the perception of SRB-induced corrosion, considering the presently most plausible explanations as well as possible early misconceptions in the understanding of severe corrosion in anoxic, sulfate-rich environments. PMID:24317078

  2. Sulfonates as Terminal Electron Acceptors for Growth of Sulfite-Reducing Bacteria (Desulfitobacterium spp.) and Sulfate-Reducing Bacteria: Effects of Inhibitors of Sulfidogenesis

    PubMed Central

    Lie, Thomas J.; Godchaux, Walter; Leadbetter, Edward R.

    1999-01-01

    This study demonstrates the ability of Desulfitobacterium spp. to utilize aliphatic sulfonates as terminal electron acceptors (TEA) for growth. Isethionate (2-hydroxyethanesulfonate) reduction by Desulfitobacterium hafniense resulted in acetate as well as sulfide accumulation in accordance with the expectation that the carbon portion of isethionate was oxidized to acetate and the sulfur was reduced to sulfide. The presence of a polypeptide, approximately 97 kDa, was evident in isethionate-grown cells of Desulfitobacterium hafniense, Desulfitobacterium sp. strain PCE 1, and the two sulfate-reducing bacteria (SRB)—Desulfovibrio desulfuricans IC1 (T. J. Lie, J. R. Leadbetter, and E. R. Leadbetter, Geomicrobiol. J. 15:135–149, 1998) and Desulfomicrobium norvegicum; this polypeptide was not detected when these bacteria were grown on TEA other than isethionate, suggesting involvement in its metabolism. The sulfate analogs molybdate and tungstate, effective in inhibiting sulfate reduction by SRB, were examined for their effects on sulfonate reduction. Molybdate effectively inhibited sulfonate reduction by strain IC1 and selectively inhibited isethionate (but not cysteate) reduction by Desulfitobacterium dehalogenans and Desulfitobacterium sp. strain PCE 1. Desulfitobacterium hafniense, however, grew with both isethionate and cysteate in the presence of molybdate. In contrast, tungstate only partially inhibited sulfonate reduction by both SRB and Desulfitobacterium spp. Similarly, another inhibitor of sulfate reduction, 1,8-dihydroxyanthraquinone, effectively inhibited sulfate reduction by SRB but only partially inhibited sulfonate reduction by both SRB and Desulfitobacterium hafniense. PMID:10508097

  3. New family of tungstate-responsive transcriptional regulators in sulfate-reducing bacteria.

    PubMed

    Kazakov, Alexey E; Rajeev, Lara; Luning, Eric G; Zane, Grant M; Siddartha, Kavya; Rodionov, Dmitry A; Dubchak, Inna; Arkin, Adam P; Wall, Judy D; Mukhopadhyay, Aindrila; Novichkov, Pavel S

    2013-10-01

    The trace elements molybdenum and tungsten are essential components of cofactors of many metalloenzymes. However, in sulfate-reducing bacteria, high concentrations of molybdate and tungstate oxyanions inhibit growth, thus requiring the tight regulation of their homeostasis. By a combination of bioinformatic and experimental techniques, we identified a novel regulator family, tungstate-responsive regulator (TunR), controlling the homeostasis of tungstate and molybdate in sulfate-reducing deltaproteobacteria. The effector-sensing domains of these regulators are similar to those of the known molybdate-responsive regulator ModE, while their DNA-binding domains are homologous to XerC/XerD site-specific recombinases. Using a comparative genomics approach, we identified DNA motifs and reconstructed regulons for 40 TunR family members. Positional analysis of TunR sites and putative promoters allowed us to classify most TunR proteins into two groups: (i) activators of modABC genes encoding a high-affinity molybdenum and tungsten transporting system and (ii) repressors of genes for toluene sulfonate uptake (TSUP) family transporters. The activation of modA and modBC genes by TunR in Desulfovibrio vulgaris Hildenborough was confirmed in vivo, and we discovered that the activation was diminished in the presence of tungstate. A predicted 30-bp TunR-binding motif was confirmed by in vitro binding assays. A novel TunR family of bacterial transcriptional factors controls tungstate and molybdate homeostasis in sulfate-reducing deltaproteobacteria. We proposed that TunR proteins participate in protection of the cells from the inhibition by these oxyanions. To our knowledge, this is a unique case of a family of bacterial transcriptional factors evolved from site-specific recombinases. PMID:23913324

  4. Application Of Immobilized Sulfate Reducing Bacteria For Permeable Reactive Barriers In Abandoned Coal Mines

    NASA Astrophysics Data System (ADS)

    Kim, K.; Hur, W.; Choi, S.; Min, K.; Baek, H.

    2006-05-01

    The decline of the Korean coal industry has been drastic in production and consumption. This has been resulted mainly from the environmental concern and the collapse of commercial viability, which has eventually necessitated the government to implement the coal industry rationalization policies to reduce coal production and close down uneconomical mines. The overall drainage rates from abandoned coal mines reaches up to 80,000 ton/day. As a measure of controlling the acid mine drainage from abandoned coal mines, reactive materials in the pathways of drainage, designed to intercept and to transform the contaminants into environmentally acceptable forms can be applied at mines with small drainage rates. The main objective of this study is to design a permeable reactive barrier(PRB) to treat low flow and/or low contaminant loads of acid mine drainage. The PRB is comprised of immobilized sulfate reducing bacteria in hard beads and limestone to remove heavy metals and to raise the pH of AMD. A laboratory reactor was used to prepare a mixed culture of sulfate reducing bacteria. The microbes were separated and mixed with biodegradable matrix to form spherical beads. In order to maintain the viability of micro-organisms for a prolonged period, substrates such as saw dust, polysaccharide or glycerol was supplemented for the beads preparation. The strength of beads fortified by powered limestone to control the permeability of PRB. Different mixtures of limestone and the immobilized beads were tested to determine hydraulic conductivity and AMD treatment capacities. The characteristics of the spherical beads at various pH of AMD was investigated.

  5. Formation of Fe-sulfides in cultures of sulfate-reducing bacteria.

    PubMed

    Gramp, Jonathan P; Bigham, Jerry M; Jones, F Sandy; Tuovinen, Olli H

    2010-03-15

    The purpose of this study was to synthesize Fe-sulfides produced with sulfate-reducing bacteria under experimental laboratory conditions. Fe-sulfides were precipitated with biologically produced sulfide in cultures growing at 22, 45, and 60 degrees C for up to 16 weeks. Abiotic controls were prepared by reacting liquid media with Na(2)S solutions. Precipitates were collected anaerobically, freeze-dried and analyzed by X-ray diffraction. Additional analyses included total Fe and S content, magnetic susceptibility, specific surface area, and scanning electron microscopy. Mackinawite (FeS) and greigite (Fe(3)S(4)) were the dominant iron sulfide phases formed in sulfate-reducing bacterial cultures. An increase in the incubation temperature from 22 to 60 degrees C enhanced the crystallinity of the Fe-sulfides. Generally, greigite was more prevalent in abiotic samples and mackinawite in biogenic materials. Pyrite (FeS(2)) was also found in abiotic precipitates. Abiotic samples had a higher magnetic susceptibility because of the greigite and displayed improved crystallinity compared to biotic materials. PMID:19962824

  6. Identical Hg isotope mass dependent fractionation signature during methylation by sulfate-reducing bacteria in sulfate and sulfate-free environment.

    PubMed

    Perrot, Vincent; Bridou, Romain; Pedrero, Zoyne; Guyoneaud, Remy; Monperrus, Mathilde; Amouroux, David

    2015-02-01

    Inorganic mercury (iHg) methylation in aquatic environments is the first step leading to monomethylmercury (MMHg) bioaccumulation in food webs and might play a role in the Hg isotopic composition measured in sediments and organisms. Methylation by sulfate reducing bacteria (SRB) under sulfate-reducing conditions is probably one of the most important sources of MMHg in natural aquatic environments, but its influence on natural Hg isotopic composition remains to be ascertained. In this context, the methylating SRB Desulfovibrio dechloracetivorans (strain BerOc1) was incubated under sulfate reducing and fumarate respiration conditions (SR and FR, respectively) to determine Hg species specific (MMHg and IHg) isotopic composition associated with methylation and demethylation kinetics. Our results clearly establish Hg isotope mass-dependent fractionation (MDF) during biotic methylation (-1.20 to +0.58‰ for δ(202)Hg), but insignificant mass-independent fractionation (MIF) (-0.12 to +0.15‰ for Δ(201)Hg). During the 24h of the time-course experiments Hg isotopic composition in the produced MMHg becomes significantly lighter than the residual IHg after 1.5h and shows similar δ(202)Hg values under both FR and SR conditions at the end of the experiments. This suggests a unique pathway responsible for the MDF of Hg isotopes during methylation by this strain regardless the metabolism of the cells. After 9 h of experiment, significant simultaneous demethylation is occurring in the culture and demethylates preferentially the lighter Hg isotopes of MMHg. Therefore, depending on their methylation/demethylation capacities, SRB communities in natural sulfate reducing conditions likely have a significant and specific influence on the Hg isotope composition of MMHg (MDF) in sediments and aquatic organisms. PMID:25564955

  7. Sulfate-reducing bacteria release barium and radium from naturally occurring radioactive material in oil-field barite

    USGS Publications Warehouse

    Phillips, E.J.P.; Landa, E.R.; Kraemer, T.; Zielinski, R.

    2001-01-01

    Scale and sludge deposits formed during oil production can contain elevated levels of Ra, often coprecipitated with barium sulfate (barite). The potential for sulfate-reducing bacteria to release 226 Ra and Ba (a Ra analog) from oil-field barite was evaluated. The concentration of dissolved Ba increased when samples containing pipe scale, tank sludge, or oil-field brine pond sediment were incubated with sulfate-reducing bacteria Desulfovibrio sp., Str LZKI, isolated from an oil-field brine pond. However, Ba release was not stoichiometric with sulfide production in oil-field samples, and <0.1% of the Ba was released. Potential for the release of 226Ra was demonstrated, and the 226 Ra release associated with sulfate-reducing activity was predictable from the amount of Ba released. As with Ba, only a fraction of the 226Ra expected from the amount of sulfide produced was released, and most of the Ra remained associated with the solid material.

  8. Corrosion of 2205 Duplex Stainless Steel Weldment in Chloride Medium Containing Sulfate-Reducing Bacteria

    NASA Astrophysics Data System (ADS)

    Antony, P. J.; Singh Raman, R. K.; Kumar, Pradeep; Raman, R.

    2008-11-01

    Influence of changes in microstructure caused due to welding on microbiologically influenced corrosion of a duplex stainless steel was studied by exposing the weldment and parent metal to chloride medium containing sulfate-reducing bacteria (SRB). Identically prepared coupons (same area and surface finish) exposed to sterile medium were used as the control. Etching-type attack was observed in the presence of SRB, which was predominant in the heat-affected zone (HAZ) of the weldment. The anodic polarization studies indicated an increase in current density for coupon exposed to SRB-containing medium as compared to that obtained for coupon exposed to sterile medium. The scanning electron microscopy (SEM) observations after anodic polarization revealed that the attack was preferentially in the ferrite phase of HAZ of the weldment, whereas it was restricted to the austenite phase of the parent metal.

  9. Analyses of Spatial Distributions of Sulfate-Reducing Bacteria and Their Activity in Aerobic Wastewater Biofilms

    PubMed Central

    Okabe, Satoshi; Itoh, Tsukasa; Satoh, Hisashi; Watanabe, Yoshimasa

    1999-01-01

    The vertical distribution of sulfate-reducing bacteria (SRB) in aerobic wastewater biofilms grown on rotating disk reactors was investigated by fluorescent in situ hybridization (FISH) with 16S rRNA-targeted oligonucleotide probes. To correlate the vertical distribution of SRB populations with their activity, the microprofiles of O2, H2S, NO2−, NO3−, NH4+, and pH were measured with microelectrodes. In addition, a cross-evaluation of the FISH and microelectrode analyses was performed by comparing them with culture-based approaches and biogeochemical measurements. In situ hybridization revealed that a relatively high abundance of the probe SRB385-stained cells (approximately 109 to 1010 cells per cm3 of biofilm) were evenly distributed throughout the biofilm, even in the oxic surface. The probe SRB660-stained Desulfobulbus spp. were found to be numerically important members of SRB populations (approximately 108 to 109 cells per cm3). The result of microelectrode measurements showed that a high sulfate-reducing activity was found in a narrow anaerobic zone located about 150 to 300 μm below the biofilm surface and above which an intensive sulfide oxidation zone was found. The biogeochemical measurements showed that elemental sulfur (S0) was an important intermediate of the sulfide reoxidation in such thin wastewater biofilms (approximately 1,500 μm), which accounted for about 75% of the total S pool in the biofilm. The contribution of an internal Fe-sulfur cycle to the overall sulfur cycle in aerobic wastewater biofilms was insignificant (less than 1%) due to the relatively high sulfate reduction rate. PMID:10543829

  10. Arsenic Thiolation and the Role of Sulfate-Reducing Bacteria from the Human Intestinal Tract

    PubMed Central

    Alava, Pradeep; Zekker, Ivar; Du Laing, Gijs

    2014-01-01

    Background: Arsenic (As) toxicity is primarily based on its chemical speciation. Although inorganic and methylated As species are well characterized in terms of metabolism and formation in the human body, the origin of thiolated methylarsenicals is still unclear. Objectives: We sought to determine whether sulfate-reducing bacteria (SRB) from the human gut are actively involved in the thiolation of monomethylarsonic acid (MMAV). Methods: We incubated human fecal and colon microbiota in a batch incubator and in a dynamic gut simulator with a dose of 0.5 mg MMAV in the absence or presence of sodium molybdate, an SRB inhibitor. We monitored the conversion of MMAV into monomethyl monothioarsonate (MMMTAV) and other As species by high-performance liquid chromatography coupled with inductively coupled plasma mass spectrometry analysis. We monitored the sulfate-reducing activity of the SRB by measuring hydrogen sulfide (H2S) production. We used molecular analysis to determine the dominant species of SRB responsible for As thiolation. Results: In the absence of sodium molybdate, the SRB activity—primarily derived from Desulfovibrio desulfuricans (piger)—was specifically and proportionally correlated (p < 0.01) to MMAV conversion into MMMTAV. Inactivating the SRB with molybdate did not result in MMAV thiolation; however, we observed that the microbiota from a dynamic gut simulator were capable of demethylating 4% of the incubated MMAV into arsenous acid (iAsIII), the trivalent and more toxic form of arsenic acid (iAsV). Conclusion: We found that SRB of human gastrointestinal origin, through their ability to produce H2S, were necessary and sufficient to induce As thiolation. The toxicological consequences of this microbial As speciation change are not yet clear. However, given the efficient epithelial absorption of thiolated methylarsenicals, we conclude that the gut microbiome—and SRB activity in particular—should be incorporated into toxicokinetic analysis carried

  11. Nitrogen Fixation By Sulfate-Reducing Bacteria in Coastal and Deep-Sea Sediments

    NASA Astrophysics Data System (ADS)

    Bertics, V. J.; Löscher, C.; Salonen, I.; Schmitz-Streit, R.; Lavik, G.; Kuypers, M. M.; Treude, T.

    2011-12-01

    Sulfate-reducing bacteria (SRB) can greatly impact benthic nitrogen (N) cycling, by for instance inhibiting coupled denitrification-nitrification through the production of sulfide or by increasing the availability of fixed N in the sediment via dinitrogen (N2)-fixation. Here, we explored several coastal and deep-sea benthic habitats within the Atlantic Ocean and Baltic Sea, for the occurrence of N2-fixation mediated by SRB. A combination of different methods including microbial rate measurements of N2-fixation and sulfate reduction, geochemical analyses (porewater nutrient profiles, mass spectrometry), and molecular analyses (CARD-FISH, HISH-SIMS, "nested" PCR, and QPCR) were applied to quantify and identify the responsible processes and organisms, respectively. Furthermore, we looked deeper into the question of whether the observed nitrogenase activity was associated with the final incorporation of N into microbial biomass or whether the enzyme activity served another purpose. At the AGU Fall Meeting, we will present and compare data from numerous stations with different water depths, temperatures, and latitudes, as well as differences in key geochemical parameters, such as organic carbon content and oxygen availability. Current metabolic and molecular data indicate that N2-fixation is occurring in many of these benthic environments and that a large part of this activity may linked to SRB.

  12. Anaerobic degradation of cyclohexane by sulfate-reducing bacteria from hydrocarbon-contaminated marine sediments

    PubMed Central

    Jaekel, Ulrike; Zedelius, Johannes; Wilkes, Heinz; Musat, Florin

    2015-01-01

    The fate of cyclohexane, often used as a model compound for the biodegradation of cyclic alkanes due to its abundance in crude oils, in anoxic marine sediments has been poorly investigated. In the present study, we obtained an enrichment culture of cyclohexane-degrading sulfate-reducing bacteria from hydrocarbon-contaminated intertidal marine sediments. Microscopic analyses showed an apparent dominance by oval cells of 1.5 × 0.8 μm. Analysis of a 16S rRNA gene library, followed by whole-cell hybridization with group- and sequence-specific oligonucleotide probes showed that these cells belonged to a single phylotype, and were accounting for more than 80% of the total cell number. The dominant phylotype, affiliated with the Desulfosarcina-Desulfococcus cluster of the Deltaproteobacteria, is proposed to be responsible for the degradation of cyclohexane. Quantitative growth experiments showed that cyclohexane degradation was coupled with the stoichiometric reduction of sulfate to sulfide. Substrate response tests corroborated with hybridization with a sequence-specific oligonucleotide probe suggested that the dominant phylotype apparently was able to degrade other cyclic and n-alkanes, including the gaseous alkane n-butane. Based on GC-MS analyses of culture extracts cyclohexylsuccinate was identified as a metabolite, indicating an activation of cyclohexane by addition to fumarate. Other metabolites detected were 3-cyclohexylpropionate and cyclohexanecarboxylate providing evidence that the overall degradation pathway of cyclohexane under anoxic conditions is analogous to that of n-alkanes. PMID:25806023

  13. Ecology of sulfate-reducing bacteria in an iron-dominated, mining-impacted freshwater sediment.

    PubMed

    Ramamoorthy, Srividhya; Piotrowski, Jeffrey S; Langner, Heiko W; Holben, William E; Morra, Matthew J; Rosenzweig, R Frank

    2009-01-01

    A legacy of lead and silver mining in its headwaters left Lake Coeur d'Alene, Idaho with a sediment body that is highly reduced and contains up to 100 g kg(-1) iron and a smaller fraction of chemically active sulfide phases. The dynamic character of these sulfides and their importance for the sequestering of contaminating trace elements prompted this study of the sulfate-reducing bacteria (SRB) involved in their production. We estimated parameters indicative of the distribution and activity of SRB in relation to season, site, and depth. Most probable number estimates and quantitative PCR assays of an SRB-specific functional gene, alpha-adenosine 5'-phosphosulfate reductase, indicated 10(3) to 10(6) cultivable cells and 10(5) to 10(7) gene copy numbers g(-1) dry wt sediment, respectively. Although culture-based estimates of SRB abundance correlated poorly with site, season, depth, total S, or pore water SO(4), non-culture-based estimates of SRB abundance were markedly higher at contaminated sites and positively correlated with pore water SO(4). Ex situ estimates of (35)SO(4) respiration and acid volatile sulfides abundance also showed strong among-site effects, indicating elevated sulfidogenesis at contaminated sites. These observations support the view that biogenic sulfides may act in concert with reduced iron to retain soluble metal(loid)s in the solid phase. PMID:19244488

  14. GENUS- AND GROUP-SPECIFIC HYBRIDIZATION PROBES FOR DETERMINATIVE AND ENVIRONMENTAL STUDIES OF SULFATE-REDUCING BACTERIA

    EPA Science Inventory

    A set of six oligonucleotides, complementary to conserved tracts of 16S rRNA from phylogenetically-defined groups of sulfate-reducing bacteria, was characterized for use as hybridization probes in determinative and environmental microbiology. our probes were genus specific and id...

  15. Stable Carbon Isotope Ratios of Lipid Biomarkers and Biomass for Sulfate-reducing Bacteria Grown with Different Substrates

    NASA Technical Reports Server (NTRS)

    Londry, K. L.; Jahnke, L. L.; Des Marais, D. J.

    2001-01-01

    We have determined isotope ratios of biomass and Fatty Acids Methyl Esters (FAME) for four Sulfate-Reducing Bacteria (SRB) grown lithotrophically and heterotrophically, and are investigating whether these biomarker signatures can reveal the ecological role and distribution of SRB within microbial mats. Additional information is contained in the original extended abstract.

  16. USING RESPIROMETRY TO MEASURE HYDROGEN UTILIZATION IN SULFATE REDUCING BACTERIA IN THE PRESENCE OF COPPER AND ZINC

    EPA Science Inventory

    A respirometric method has been developed to measure hydrogen utilization by sulfate reducing bacteria (SRB). One application of this method has been to test inhibitory metals effects on the SRB culture used in a novel acid mine drainage treatment technology. As a control param...

  17. BIOREACTOR ECONOMICS, SIZE AND TIME OF OPERATION (BEST) COMPUTER SIMULATOR FOR DESIGNING SULFATE-REDUCING BACTERIA FIELD BIOREACTORS

    EPA Science Inventory

    BEST (bioreactor economics, size and time of operation) is an Excel™ spreadsheet-based model that is used in conjunction with the public domain geochemical modeling software, PHREEQCI. The BEST model is used in the design process of sulfate-reducing bacteria (SRB) field bioreacto...

  18. Field Tests of “In-Situ” Remediation of Groundwater From Dissolved Mercury Utilizing Sulfate Reducing Bacteria

    EPA Science Inventory

    Field tests of biologically active filters have been conducted at groundwater mercury pollution site in Pavlodar, Kazakhstan. The biofilters represented cultures of sulfate-reducing bacteria (SRB) immobilized on claydite imbedded in wells drilled down to basalt clay layer (14-17 ...

  19. Tackling the minority: sulfate-reducing bacteria in an archaea-dominated subsurface biofilm

    PubMed Central

    Probst, Alexander J; Holman, Hoi-Ying N; DeSantis, Todd Z; Andersen, Gary L; Birarda, Giovanni; Bechtel, Hans A; Piceno, Yvette M; Sonnleitner, Maria; Venkateswaran, Kasthuri; Moissl-Eichinger, Christine

    2013-01-01

    Archaea are usually minor components of a microbial community and dominated by a large and diverse bacterial population. In contrast, the SM1 Euryarchaeon dominates a sulfidic aquifer by forming subsurface biofilms that contain a very minor bacterial fraction (5%). These unique biofilms are delivered in high biomass to the spring outflow that provides an outstanding window to the subsurface. Despite previous attempts to understand its natural role, the metabolic capacities of the SM1 Euryarchaeon remain mysterious to date. In this study, we focused on the minor bacterial fraction in order to obtain insights into the ecological function of the biofilm. We link phylogenetic diversity information with the spatial distribution of chemical and metabolic compounds by combining three different state-of-the-art methods: PhyloChip G3 DNA microarray technology, fluorescence in situ hybridization (FISH) and synchrotron radiation-based Fourier transform infrared (SR-FTIR) spectromicroscopy. The results of PhyloChip and FISH technologies provide evidence for selective enrichment of sulfate-reducing bacteria, which was confirmed by the detection of bacterial dissimilatory sulfite reductase subunit B (dsrB) genes via quantitative PCR and sequence-based analyses. We further established a differentiation of archaeal and bacterial cells by SR-FTIR based on typical lipid and carbohydrate signatures, which demonstrated a co-localization of organic sulfate, carbonated mineral and bacterial signatures in the biofilm. All these results strongly indicate an involvement of the SM1 euryarchaeal biofilm in the global cycles of sulfur and carbon and support the hypothesis that sulfidic springs are important habitats for Earth's energy cycles. Moreover, these investigations of a bacterial minority in an Archaea-dominated environment are a remarkable example of the great power of combining highly sensitive microarrays with label-free infrared imaging. PMID:23178669

  20. Integrative analysis of the interactions between Geobacter spp. and sulfate-reducing bacteria during uranium bioremediation

    NASA Astrophysics Data System (ADS)

    Barlett, M.; Zhuang, K.; Mahadevan, R.; Lovley, D. R.

    2011-11-01

    Enhancing microbial U(VI) reduction with the addition of organic electron donors is a promising strategy for immobilizing uranium in contaminated groundwaters, but has yet to be optimized because of a poor understanding of the factors controlling the growth of various microbial communities during bioremediation. In previous field trials in which acetate was added to the subsurface, there were two distinct phases: an initial phase in which acetate-oxidizing, U(VI)-reducing Geobacter predominated and U(VI) was effectively reduced and a second phase in which acetate-oxidizing sulfate reducing bacteria (SRB) predominated and U(VI) reduction was poor. The interaction of Geobacter and SRB was investigated both in sediment incubations that mimicked in situ bioremediation and with in silico metabolic modeling. In sediment incubations, Geobacter grew quickly but then declined in numbers as the microbially reducible Fe(III) was depleted whereas the SRB grow more slowly and reached dominance after 30-40 days. Modeling predicted a similar outcome. Additional modeling in which the relative initial percentages of the Geobacter and SRB were varied indicated that there was little to no competitive interaction between Geobacter and SRB when acetate was abundant. Further simulations suggested that the addition of Fe(III) would revive the Geobacter, but have little to no effect on the SRB. This result was confirmed experimentally. The results demonstrate that it is possible to predict the impact of amendments on important components of the subsurface microbial community during groundwater bioremediation. The finding that Fe(III) availability, rather than competition with SRB, is the key factor limiting the activity of Geobacter during in situ uranium bioremediation will aid in the design of improved uranium bioremediation strategies.

  1. Integrative analysis of Geobacter spp. and sulfate-reducing bacteria during uranium bioremediation

    NASA Astrophysics Data System (ADS)

    Barlett, M.; Zhuang, K.; Mahadevan, R.; Lovley, D.

    2012-03-01

    Enhancing microbial U(VI) reduction with the addition of organic electron donors is a promising strategy for immobilizing uranium in contaminated groundwaters, but has yet to be optimized because of a poor understanding of the factors controlling the growth of various microbial communities during bioremediation. In previous field trials in which acetate was added to the subsurface, there were two distinct phases: an initial phase in which acetate-oxidizing, U(VI)-reducing Geobacter predominated and U(VI) was effectively reduced and a second phase in which acetate-oxidizing sulfate reducing bacteria (SRB) predominated and U(VI) reduction was poor. The interaction of Geobacter and SRB was investigated both in sediment incubations that mimicked in situ bioremediation and with in silico metabolic modeling. In sediment incubations, Geobacter grew quickly but then declined in numbers as the microbially reducible Fe(III) was depleted whereas the SRB grow more slowly and reached dominance after 30-40 days. Modeling predicted a similar outcome. Additional modeling in which the relative initial percentages of the Geobacter and SRB were varied indicated that there was little to no competitive interaction between Geobacter and SRB when acetate was abundant. Further simulations suggested that the addition of Fe(III) would revive the Geobacter, but have little to no effect on the SRB. This result was confirmed experimentally. The results demonstrate that it is possible to predict the impact of amendments on important components of the subsurface microbial community during groundwater bioremediation. The finding that Fe(III) availability, rather than competition with SRB, is the key factor limiting the activity of Geobacter during in situ uranium bioremediation will aid in the design of improved uranium bioremediation strategies.

  2. Sulfate Reducing Bacteria and Mycobacteria Dominate the Biofilm Communities in a Chloraminated Drinking Water Distribution System.

    PubMed

    Gomez-Smith, C Kimloi; LaPara, Timothy M; Hozalski, Raymond M

    2015-07-21

    The quantity and composition of bacterial biofilms growing on 10 water mains from a full-scale chloraminated water distribution system were analyzed using real-time PCR targeting the 16S rRNA gene and next-generation, high-throughput Illumina sequencing. Water mains with corrosion tubercles supported the greatest amount of bacterial biomass (n = 25; geometric mean = 2.5 × 10(7) copies cm(-2)), which was significantly higher (P = 0.04) than cement-lined cast-iron mains (n = 6; geometric mean = 2.0 × 10(6) copies cm(-2)). Despite spatial variation of community composition and bacterial abundance in water main biofilms, the communities on the interior main surfaces were surprisingly similar, containing a core group of operational taxonomic units (OTUs) assigned to only 17 different genera. Bacteria from the genus Mycobacterium dominated all communities at the main wall-bulk water interface (25-78% of the community), regardless of main age, estimated water age, main material, and the presence of corrosion products. Further sequencing of the mycobacterial heat shock protein gene (hsp65) provided species-level taxonomic resolution of mycobacteria. The two dominant Mycobacteria present, M. frederiksbergense (arithmetic mean = 85.7% of hsp65 sequences) and M. aurum (arithmetic mean = 6.5% of hsp65 sequences), are generally considered to be nonpathogenic. Two opportunistic pathogens, however, were detected at low numbers: M. hemophilum (arithmetic mean = 1.5% of hsp65 sequences) and M. abscessus (arithmetic mean = 0.006% of hsp65 sequences). Sulfate-reducing bacteria from the genus Desulfovibrio, which have been implicated in microbially influenced corrosion, dominated all communities located underneath corrosion tubercules (arithmetic mean = 67.5% of the community). This research provides novel insights into the quantity and composition of biofilms in full-scale drinking water distribution systems, which is critical for assessing the risks to public health and to the

  3. A Comparative Genomic Analysis of Energy Metabolism in Sulfate Reducing Bacteria and Archaea

    PubMed Central

    Pereira, Inês A. Cardoso; Ramos, Ana Raquel; Grein, Fabian; Marques, Marta Coimbra; da Silva, Sofia Marques; Venceslau, Sofia Santos

    2011-01-01

    The number of sequenced genomes of sulfate reducing organisms (SRO) has increased significantly in the recent years, providing an opportunity for a broader perspective into their energy metabolism. In this work we carried out a comparative survey of energy metabolism genes found in 25 available genomes of SRO. This analysis revealed a higher diversity of possible energy conserving pathways than classically considered to be present in these organisms, and permitted the identification of new proteins not known to be present in this group. The Deltaproteobacteria (and Thermodesulfovibrio yellowstonii) are characterized by a large number of cytochromes c and cytochrome c-associated membrane redox complexes, indicating that periplasmic electron transfer pathways are important in these bacteria. The Archaea and Clostridia groups contain practically no cytochromes c or associated membrane complexes. However, despite the absence of a periplasmic space, a few extracytoplasmic membrane redox proteins were detected in the Gram-positive bacteria. Several ion-translocating complexes were detected in SRO including H+-pyrophosphatases, complex I homologs, Rnf, and Ech/Coo hydrogenases. Furthermore, we found evidence that cytoplasmic electron bifurcating mechanisms, recently described for other anaerobes, are also likely to play an important role in energy metabolism of SRO. A number of cytoplasmic [NiFe] and [FeFe] hydrogenases, formate dehydrogenases, and heterodisulfide reductase-related proteins are likely candidates to be involved in energy coupling through electron bifurcation, from diverse electron donors such as H2, formate, pyruvate, NAD(P)H, β-oxidation, and others. In conclusion, this analysis indicates that energy metabolism of SRO is far more versatile than previously considered, and that both chemiosmotic and flavin-based electron bifurcating mechanisms provide alternative strategies for energy conservation. PMID:21747791

  4. Fermentation couples Chloroflexi and sulfate-reducing bacteria to Cyanobacteria in hypersaline microbial mats.

    PubMed

    Lee, Jackson Z; Burow, Luke C; Woebken, Dagmar; Everroad, R Craig; Kubo, Mike D; Spormann, Alfred M; Weber, Peter K; Pett-Ridge, Jennifer; Bebout, Brad M; Hoehler, Tori M

    2014-01-01

    Past studies of hydrogen cycling in hypersaline microbial mats have shown an active nighttime cycle, with production largely from Cyanobacteria and consumption from sulfate-reducing bacteria (SRB). However, the mechanisms and magnitude of hydrogen cycling have not been extensively studied. Two mats types near Guerrero Negro, Mexico-permanently submerged Microcoleus microbial mat (GN-S), and intertidal Lyngbya microbial mat (GN-I)-were used in microcosm diel manipulation experiments with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), molybdate, ammonium addition, and physical disruption to understand the processes responsible for hydrogen cycling between mat microbes. Across microcosms, H2 production occurred under dark anoxic conditions with simultaneous production of a suite of organic acids. H2 production was not significantly affected by inhibition of nitrogen fixation, but rather appears to result from constitutive fermentation of photosynthetic storage products by oxygenic phototrophs. Comparison to accumulated glycogen and to CO2 flux indicated that, in the GN-I mat, fermentation released almost all of the carbon fixed via photosynthesis during the preceding day, primarily as organic acids. Across mats, although oxygenic and anoxygenic phototrophs were detected, cyanobacterial [NiFe]-hydrogenase transcripts predominated. Molybdate inhibition experiments indicated that SRBs from a wide distribution of DsrA phylotypes were responsible for H2 consumption. Incubation with (13)C-acetate and NanoSIMS (secondary ion mass-spectrometry) indicated higher uptake in both Chloroflexi and SRBs relative to other filamentous bacteria. These manipulations and diel incubations confirm that Cyanobacteria were the main fermenters in Guerrero Negro mats and that the net flux of nighttime fermentation byproducts (not only hydrogen) was largely regulated by the interplay between Cyanobacteria, SRBs, and Chloroflexi. PMID:24616716

  5. Fermentation couples Chloroflexi and sulfate-reducing bacteria to Cyanobacteria in hypersaline microbial mats

    PubMed Central

    Lee, Jackson Z.; Burow, Luke C.; Woebken, Dagmar; Everroad, R. Craig; Kubo, Mike D.; Spormann, Alfred M.; Weber, Peter K.; Pett-Ridge, Jennifer; Bebout, Brad M.; Hoehler, Tori M.

    2013-01-01

    Past studies of hydrogen cycling in hypersaline microbial mats have shown an active nighttime cycle, with production largely from Cyanobacteria and consumption from sulfate-reducing bacteria (SRB). However, the mechanisms and magnitude of hydrogen cycling have not been extensively studied. Two mats types near Guerrero Negro, Mexico—permanently submerged Microcoleus microbial mat (GN-S), and intertidal Lyngbya microbial mat (GN-I)—were used in microcosm diel manipulation experiments with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), molybdate, ammonium addition, and physical disruption to understand the processes responsible for hydrogen cycling between mat microbes. Across microcosms, H2 production occurred under dark anoxic conditions with simultaneous production of a suite of organic acids. H2 production was not significantly affected by inhibition of nitrogen fixation, but rather appears to result from constitutive fermentation of photosynthetic storage products by oxygenic phototrophs. Comparison to accumulated glycogen and to CO2 flux indicated that, in the GN-I mat, fermentation released almost all of the carbon fixed via photosynthesis during the preceding day, primarily as organic acids. Across mats, although oxygenic and anoxygenic phototrophs were detected, cyanobacterial [NiFe]-hydrogenase transcripts predominated. Molybdate inhibition experiments indicated that SRBs from a wide distribution of DsrA phylotypes were responsible for H2 consumption. Incubation with 13C-acetate and NanoSIMS (secondary ion mass-spectrometry) indicated higher uptake in both Chloroflexi and SRBs relative to other filamentous bacteria. These manipulations and diel incubations confirm that Cyanobacteria were the main fermenters in Guerrero Negro mats and that the net flux of nighttime fermentation byproducts (not only hydrogen) was largely regulated by the interplay between Cyanobacteria, SRBs, and Chloroflexi. PMID:24616716

  6. Improved method for enumerating sulfate-reducing bacteria using optical density.

    PubMed

    Bernardez, L A; de Andrade Lima, L R P

    2015-01-01

    The photometric determination of bacterial concentration can be affected by secondary scattering and other interferences. The conventional growth medium for sulfate-reducing bacteria (SRB) has iron that precipitates as iron sulfides, a dark precipitate which is useful to indicate bacterial activity. However, iron hydroxides also precipitate at high pH values and the presence of these precipitates interferes considerably in the optical density of the solution affecting estimates of the cell population thus seriously limiting the use of the conventional method. In this method a modification of the current method improves the measurement of the optical density of a solution with SRB cells. •The method consists of an acidification with hydrochloric acid of a sample of a mixed culture of SRB enriched from the produced water from oil fields to pH below 2.•The results show that the relationship between the bacterial dry mass and absorbance is exponential in the observed range. It was observed a large slope in the linearized fit equation, and the acidified solution does not change the integrity of the SRB cells after the treatment.•The results of the kinetic experiments, including the bacterial growth time evolution, demonstrate the applicability of the method. PMID:26150995

  7. Biosynthesis of CdS nanoparticles: A fluorescent sensor for sulfate-reducing bacteria detection.

    PubMed

    Qi, Peng; Zhang, Dun; Zeng, Yan; Wan, Yi

    2016-01-15

    CdS nanoparticles were synthesized with an environmentally friendly method by taking advantage of the characteristic metabolic process of sulfate-reducing bacteria (SRB), and used as fluorescence labels for SRB detection. The presence of CdS nanoparticles was observed within and immediately surrounded bacterial cells, indicating CdS nanoparticles were synthesized both intracellularly and extracellularly. Moreover, fluorescent properties of microbial synthesized CdS nanoparticles were evaluated for SRB detection, and a linear relationship between fluorescence intensity and the logarithm of bacterial concentration was obtained in the range of from 1.0×10(2) to 1.0×10(7)cfu mL(-1). The proposed SRB detection method avoided the use of biological bio-recognition elements which are easy to lose their specific recognizing abilities, and the bacterial detection time was greatly shortened compared with the widely used MPN method which would take up to 15 days to accomplish the detection process. PMID:26592588

  8. Analyses of the vertical and temporal distribution of sulfate-reducing bacteria in Lake Aha (China)

    NASA Astrophysics Data System (ADS)

    Wang, M. Y.; Liang, X. B.; Yuan, X. Y.; Zhang, W.; Zeng, J.

    2008-03-01

    In April and September of 2005, two sediment cores were collected from Lake Aha, which is polluted by the acid mine drainage of the mining industries. Sulfate-reducing bacteria (SRB) groups and their quantity were analyzed by using PCR and FISH (fluorescence in situ hybridization), respectively. The results showed that four SRB groups ( Desulfotomaculum, Desulfobulbus, Desulfococcus Desulfonema Desulfosarcina and Desulfovibrio Desulfomicrobium) were detected in September, while only three SRB groups ( Desulfotomaculum, Desulfobulbus and Desulfococcus Desulfonema Desulfosarcina) were detected in April. Desulfovibrio Desulfomicrobium was not detected and was expected to exist inactively, in April. Meanwhile, the distribution of every SRB group was wider in September than in April. The results indicated that different SRB groups had different vertical and temporal distribution. The vertical and temporal distribution of SRB was mainly in the upper sediments, and the number of SRB groups and quantity were larger in September than in April. It suggested that the environmental conditions of sediments in September were more suitable for SRB.

  9. Improved method for enumerating sulfate-reducing bacteria using optical density

    PubMed Central

    Bernardez, L.A.; de Andrade Lima, L.R.P.

    2015-01-01

    The photometric determination of bacterial concentration can be affected by secondary scattering and other interferences. The conventional growth medium for sulfate-reducing bacteria (SRB) has iron that precipitates as iron sulfides, a dark precipitate which is useful to indicate bacterial activity. However, iron hydroxides also precipitate at high pH values and the presence of these precipitates interferes considerably in the optical density of the solution affecting estimates of the cell population thus seriously limiting the use of the conventional method. In this method a modification of the current method improves the measurement of the optical density of a solution with SRB cells. • The method consists of an acidification with hydrochloric acid of a sample of a mixed culture of SRB enriched from the produced water from oil fields to pH below 2. • The results show that the relationship between the bacterial dry mass and absorbance is exponential in the observed range. It was observed a large slope in the linearized fit equation, and the acidified solution does not change the integrity of the SRB cells after the treatment. • The results of the kinetic experiments, including the bacterial growth time evolution, demonstrate the applicability of the method. PMID:26150995

  10. Component analysis and heavy metal adsorption ability of extracellular polymeric substances (EPS) from sulfate reducing bacteria.

    PubMed

    Yue, Zheng-Bo; Li, Qing; Li, Chuan-chuan; Chen, Tian-hu; Wang, Jin

    2015-10-01

    Extracellular polymeric substances (EPS) play an important role in the treatment of acid mine drainage (AMD) by sulfate-reducing bacteria (SRB). In this paper, Desulfovibrio desulfuricans was used as the test strain to explore the effect of heavy metals on the components and adsorption ability of EPS. Fourier-transform infrared (FTIR) spectroscopy analysis results showed that heavy metals did not influence the type of functional groups of EPS. Potentiometric titration results indicated that the acidic constants (pKa) of the EPS fell into three ranges of 3.5-4.0, 5.9-6.7, and 8.9-9.8. The adsorption site concentrations of the surface functional groups also increased. Adsorption results suggested that EPS had a specific binding affinity for the dosed heavy metal, and that EPS extracted from the Zn(2+)-dosed system had a higher binding affinity for all heavy metals. Additionally, Zn(2+) decreased the inhibitory effects of Cd(2+) and Cu(2+) on the SRB. PMID:26210529

  11. Immunomagnetically Captured Thermophilic Sulfate-Reducing Bacteria from North Sea Oil Field Waters

    PubMed Central

    Christensen, Bjørn; Torsvik, Terje; Lien, Torleiv

    1992-01-01

    Immunomagnetic beads (IMB) were used to recover thermophilic sulfate-reducing bacteria from oil field waters from oil production platforms in the Norwegian sector of the North Sea. IMB coated with polyclonal antibodies against whole-cell antigens of the thermophilic Thermodesulfobacterium mobile captured strains GFA1, GFA2, and GFA3. GFA1 was serologically and morphologically identical to T. mobile. GFA2 and GFA3 were spore forming and similar to the Desulfotomaculum strains T90A and T93B previously isolated from North Sea oil field waters by a classical enrichment procedure. Western blots (immunoblots) of whole cells showed that GFA2, GFA3, T90A, and T93B are different serotypes of the same Desulfotomaculum species. Monoclonal antibodies (MAb) against T. mobile type strain cells were produced and used as capture agents on IMB. These MAb, named A4F4, were immunoglobulin M; they were specific to T. mobile and directed against lipopolysaccharides. The prevailing cells immunocaptured with MAb A4F4 were morphologically and serologically similar to T. mobile type strain cells. T. mobile was not detected in these oil field waters by classical enrichment procedures. Furthermore, extraction with antibody-coated IMB allowed pure strains to be isolated directly from primary enrichment cultures without prior time-consuming subculturing and consecutive transfers to selective media. Images PMID:16348693

  12. Monitoring microbial populations of sulfate-reducing bacteria using an impedimetric immunosensor based on agglutination assay.

    PubMed

    Wan, Yi; Zhang, Dun; Hou, Baorong

    2009-11-15

    An impedimetric immunosensor was fabricated for rapid and non-labeled detection of sulfate-reducing bacteria, Desulforibrio caledoiensis (SRB) by immobilizing lectin-Concanavalin A using an agglutination assay. The immobilization of lectin was conducted using amine coupling on the surface of a gold (Au) electrode assembled with 11-Mercaptoundecanoic acid. Electrochemical impedance spectroscopy (EIS) was used to verify the stepwise assembly of the sensor system. The work conditions of the impedimetric immunosensor, such as pH of the buffer solutions and the incubation time of lectin, were optimized. Faradic impedance spectra for charge transfer for the redox probe Fe(CN)(6)(3-/4-)were measured to determine SRB concentrations. The diameter of the Nyquist diagram that is equal to the charge-transfer resistance (R(ct)) increased with increasing SRB concentration. A linear relationship between R(ct) and SRB concentration was obtained in SRB concentration range of 1.8 to 1.8 x 10(7)cfu/ml. The variation of the SRB population during the growth process was also monitored using the impedimetric immunosensor. This approach has great potential for simple, low-cost, and time-saving monitoring of microbial populations. PMID:19782217

  13. Diversity of sulfate-reducing bacteria in a plant using deep geothermal energy

    NASA Astrophysics Data System (ADS)

    Alawi, Mashal; Lerm, Stephanie; Vetter, Alexandra; Wolfgramm, Markus; Seibt, Andrea; Würdemann, Hilke

    2011-06-01

    Enhanced process understanding of engineered geothermal systems is a prerequisite to optimize plant reliability and economy. We investigated microbial, geochemical and mineralogical aspects of a geothermal groundwater system located in the Molasse Basin by fluid analysis. Fluids are characterized by temperatures ranging from 61°C to 103°C, salinities from 600 to 900 mg/l and a dissolved organic carbon content (DOC) between 6.4 to 19.3 mg C/l. The microbial population of fluid samples was analyzed by genetic fingerprinting techniques based on PCR-amplified 16S rRNA- and dissimilatory sulfite reductase genes. Despite of the high temperatures, microbes were detected in all investigated fluids. Fingerprinting and DNA sequencing enabled a correlation to metabolic classes and biogeochemical processes. The analysis revealed a broad diversity of sulfate-reducing bacteria. Overall, the detection of microbes known to be involved in biocorrosion and mineral precipitation indicates that microorganisms could play an important role for the understanding of processes in engineered geothermal systems.

  14. Sulfate-reducing bacteria inhabiting natural corrosion deposits from marine steel structures.

    PubMed

    Païssé, Sandrine; Ghiglione, Jean-François; Marty, Florence; Abbas, Ben; Gueuné, Hervé; Amaya, José Maria Sanchez; Muyzer, Gerard; Quillet, Laurent

    2013-08-01

    In the present study, investigations were conducted on natural corrosion deposits to better understand the role of sulfate-reducing bacteria (SRB) in the accelerated corrosion process of carbon steel sheet piles in port environments. We describe the abundance and diversity of total and metabolically active SRB within five natural corrosion deposits located within tidal or low water zone and showing either normal or accelerated corrosion. By using molecular techniques, such as quantitative real-time polymerase chain reaction, denaturing gel gradient electrophoresis, and sequence cloning based on 16S rRNA, dsrB genes, and their transcripts, we demonstrated a clear distinction between SRB population structure inhabiting normal or accelerated low-water corrosion deposits. Although SRB were present in both normal and accelerated low-water corrosion deposits, they dominated and were exclusively active in the inner and intermediate layers of accelerated corrosion deposits. We also highlighted that some of these SRB populations are specific to the accelerated low-water corrosion deposit environment in which they probably play a dominant role in the sulfured corrosion product enrichment. PMID:23086338

  15. The effects of sulfate reducing bacteria on stainless steel and Ni-Cr-Mo alloy weldments

    SciTech Connect

    Petersen, T.A.; Taylor, S.R.

    1995-10-01

    Previous research in this laboratory demonstrated a direct correlation between alloy composition and corrosion susceptibility of stainless steel and Ni-Cr-Mo alloy weldments exposed to lake water augmented with sulfate reducing bacteria (SRB). It was shown that lake water containing an active SRB population reduced the polarization resistance (R{sub p}) on all alloys studied including those with 9% Mo. In addition, preliminary evidence indicated that edge preparation and weld heat input were also important parameters in determining corrosion performance. This prior research, however, looked at ``doctored`` weldments in which the thermal oxide in the heat affected zone was removed. The objectives of the research presented here are to further confirm these observations using as-received welds. The materials examined (listed in increasing alloy content) are 1/4 inch thick plates of 316L, 317L, AL6XN (6% Mo), alloy 625 clad steel, alloy 625, and alloy 686. Materials were welded using the tungsten inert gas (TIG) process in an argon purged environment. In addition, 317L was welded in air to test oxide effects. All samples were prepared for welding by grinding to a V-edge, except the 625 clad steel samples which were prepared using a J-edge. Electrochemical performance of welded samples was monitored in four glass cells which could each allow exposure of 8 samples to the same environment. Two cells contained lake water inoculated with SRS, and two cells contained sterilized lake water. The open circuit potential (E{sub oc}) and R{sub p} was used to correlate corrosion susceptibility and bacterial activity with alloy composition and welding parameters.

  16. [Rice straw and sewage sludge as carbon sources for sulfate-reducing bacteria treating acid mine drainage].

    PubMed

    Su, Yu; Wang, Jin; Peng, Shu-chuan; Yue, Zheng-bo; Chen, Tian-hu; Jin, Jie

    2010-08-01

    The performance of three organic carbon sources was assessed in terms of sulfate reduction and main metal removal, by using sewage sludge as the source of sulfate-reducing bacteria (SRB) and adding rice straw and ethanol with equal quantity. Results indicated that sewage sludge which contained certain amount of alkaline material could neutralize acidity of acid mine drainage(AMD) on the first day of experiment, elevating pH value from the initial 2.5 to around 5.4-6.3 and achieving suitable pH condition for SRB growth. Sewage sludge contained fewer biodegradable organic substance, reactive mixture with single sewage sludge showed the lowest sulfate reduction (65.9%). When the single sewage sludge was supplemented with rice straw, SRB reducing sulfate was enhanced (79.2%), because the degradation rate of rice straw was accelerated by the specific bacteria in sewage sludge, providing relatively abundant carbon source for SRB. Control experiment with ethanol was most effective in promoting sulfate reduction (97.9%). Metal removal efficiency in all three reactors was as high as 99% for copper, early copper removal was mainly attributed to the adsorption capacity of sewage sludge prior to SRB acclimation. It is feasible for using rice straw and sewage sludge as carbon sources for SRB treating acid mine drainage at a low cost, this may have significant implication for in situ bioremediation of mine environment. PMID:21090305

  17. Mo enrichment in black shale and reduction of molybdate by sulfate-reducing bacteria (SRB) (Invited)

    NASA Astrophysics Data System (ADS)

    Xu, H.; Barton, L. L.

    2010-12-01

    The Lower Cambrian Black shale in Zunyi area of Guizhou Province, Southern China contains significant amount of Mo, As, and sulfide minerals. Additionally, Mo and sulfides are closely associated with organic matter of kerogen. Transmission electron microscopy (TEM) results show pyrite micro-crystals and Mo-As-S-bearing carbon (kerogen). High-resolution TEM image shows that Mo-rich areas are Mo-sulfide (molybdenite) layers that form poorly crystalline structures in organic carbon matrix. X-ray energy-dispersive spectra (EDS) indicate composition from the pyrite and the Mo-rich area. The black shale is very unique because of its high Mo concentration. One possible mechanism for enriching Mo from paleo-seawater is the involvement of SRB. Molybdate is an essential trace element required by biological systems including the anaerobic sulfate-reducing bacteria (SRB); however, detrimental consequences may occur if molybdate is present in high concentrations in the environment. We followed the growth of Desulfovibrio gigas ATCC 19364, D. vulgaris Hildenborough, D. desulfuricans DSM 642, and D. desulfuricans DSM 27774 in media containing sub-lethal levels of molybdate and observed a red-brown color in the culture fluid. Spectral analysis of the culture fluid revealed absorption peaks at 467 nm, 395 nm and 314 nm and this color is proposed to be a molybdate-sulfide complex. Reduction of molybdate with the formation of molybdate disulfide occurs in the periplasm D. gigas and D. desulfuricans DSM 642. From these results we suggest that the occurrence of poorly crystalline Mo-sulfides in black shale may be a result from SRB reduction and selective enrichment of Mo in paleo-seawater. We suggest that similar SRB mechanism could cause the Mo enrichment in a ~ 2.5 billion years old late Archean McRae Shale, which is related to the great oxidation event of early earth atmosphere.

  18. Diversity and Characterization of Sulfate-Reducing Bacteria in Groundwater at a Uranium Mill Tailings Site

    PubMed Central

    Chang, Yun-Juan; Peacock, Aaron D.; Long, Philip E.; Stephen, John R.; McKinley, James P.; Macnaughton, Sarah J.; Hussain, A. K. M. Anwar; Saxton, Arnold M.; White, David C.

    2001-01-01

    Microbially mediated reduction and immobilization of U(VI) to U(IV) plays a role in both natural attenuation and accelerated bioremediation of uranium-contaminated sites. To realize bioremediation potential and accurately predict natural attenuation, it is important to first understand the microbial diversity of such sites. In this paper, the distribution of sulfate-reducing bacteria (SRB) in contaminated groundwater associated with a uranium mill tailings disposal site at Shiprock, N.Mex., was investigated. Two culture-independent analyses were employed: sequencing of clone libraries of PCR-amplified dissimilatory sulfite reductase (DSR) gene fragments and phospholipid fatty acid (PLFA) biomarker analysis. A remarkable diversity among the DSR sequences was revealed, including sequences from δ-Proteobacteria, gram-positive organisms, and the Nitrospira division. PLFA analysis detected at least 52 different mid-chain-branched saturate PLFA and included a high proportion of 10me16:0. Desulfotomaculum and Desulfotomaculum-like sequences were the most dominant DSR genes detected. Those belonging to SRB within δ-Proteobacteria were mainly recovered from low-uranium (≤302 ppb) samples. One Desulfotomaculum-like sequence cluster overwhelmingly dominated high-U (>1,500 ppb) sites. Logistic regression showed a significant influence of uranium concentration over the dominance of this cluster of sequences (P = 0.0001). This strong association indicates that Desulfotomaculum has remarkable tolerance and adaptation to high levels of uranium and suggests the organism's possible involvement in natural attenuation of uranium. The in situ activity level of Desulfotomaculum in uranium-contaminated environments and its comparison to the activities of other SRB and other functional groups should be an important area for future research. PMID:11425735

  19. Improved Methodology for Bioremoval of Black Crusts on Historical Stone Artworks by Use of Sulfate-Reducing Bacteria

    PubMed Central

    Cappitelli, Francesca; Zanardini, Elisabetta; Ranalli, Giancarlo; Mello, Emilio; Daffonchio, Daniele; Sorlini, Claudia

    2006-01-01

    An improved methodology to remove black crusts from stone by using Desulfovibrio vulgaris subsp. vulgaris ATCC 29579, a sulfate-reducing bacterium, is presented. The strain removed 98% of the sulfates of the crust in a 45-h treatment. Precipitation of black iron sulfide was avoided using filtration of a medium devoid of iron. Among three cell carriers, Carbogel proved to be superior to both sepiolite and Hydrobiogel-97, as it allowed an easy application of the bacteria, kept the system in a state where microbial activity was maintained, and allowed easy removal of the cells after the treatment. PMID:16672524

  20. The ecophysiology of sulfur isotope fractionation by sulfate reducing bacteria in response to variable environmental conditions

    NASA Astrophysics Data System (ADS)

    Leavitt, W.; Bradley, A. S.; Johnston, D. T.; Pereira, I. A. C.; Venceslau, S.; Wallace, C.

    2014-12-01

    Microbial sulfate reducers (MSR) drive the Earth's biogeochemical sulfur cycle. At the heart of this energy metabolism is a cascade of redox transformations coupling organic carbon and/or hydrogen oxidation to the dissimilatory reduction of sulfate to sulfide. The sulfide produced is depleted in the heavier isotopes of sulfur relative to sulfate. The magnitude of discrimination (fractionation) depends on: i) the cell-specific sulfate reduction rate (csSRR, Kaplan & Rittenberg (1964) Can. J. Microbio.; Chambers et al. (1975) Can. J. Microbio; Sim et al. (2011) GCA; Leavitt et al. (2013) PNAS), ii) the ambient sulfate concentration (Harrison & Thode (1958) Research; Habicht et al. (2002) Science; Bradley et al. in review), iii) both sulfate and electron donor availability, or iv) an intrinsic physiological limitation (e.g. cellular division rate). When neither sulfate nor electron donor limits csSRR a more complex function relates the magnitude of isotope fractionation to cell physiology and environmental conditions. In recent and on-going work we have examined the importance of enzyme-specific fractionation factors, as well as the influence of electron donor or electron acceptor availability under carefully controlled culture conditions (e.g. Leavitt et al. (2013) PNAS). In light of recent advances in MSR genetics and biochemistry we utilize well-characterized mutant strains, along with a continuous-culture methodology (Leavitt et al. (2013) PNAS) to further probe the fractionation capacity of this metabolism under controlled physiological conditions. We present our latest findings on the magnitude of S and D/H isotope fractionation in both wild type and mutant strains. We will discuss these in light of recent theoretical advances (Wing & Halevy (2014) PNAS), examining the mode and relevance of MSR isotope fractionation in the laboratory to modern and ancient environmental settings, particularly anoxic marine sediments.

  1. Enzymatic catalysis of mercury methylation by planktonic and biofilm cultures of sulfate- reducing bacteria

    NASA Astrophysics Data System (ADS)

    Lin, C.; Kampalath, R.; Jay, J.

    2007-12-01

    While biofilms are now known to be the predominant form of microbial growth in nature, little is known about their role in environmental mercury (Hg) methylation. Due to its long-range atmospheric transport, Hg contamination of food chains is a worldwide problem, impacting even pristine areas. Among different forms of mercury species, methylmercury (MeHg) is an extremely neurotoxic and biomagnification-prone compound that can lead to severely adverse health effects on wildlife and humans. Considerable studies have shown that in the aquatic environment the external supply of MeHg is not sufficient to account for MeHg accumulation in biota and in situ biological MeHg formation plays a critical role in determining the amount of MeHg in food webs; moreover, sulfate-reducing bacteria (SRB) has been identified as the principal Hg-methylating organisms in nature. In a wide range of aquatic systems wetlands are considered important sites for Hg methylation mostly because of the environmental factors that promote microbial activity within, and biofilms are especially important in wetland ecosystems due to large amount of submerged surfaces. Although recent work has focused on the environmental factors that control MeHg production and the conditions that affect the availability of inorganic Hg to SRB, much remains to be understood about the biochemical mechanism of the Hg methylation process in SRB, especially in the biofilm-growth of these microbes. Data from our previous study with SRB strains isolated from a coastal wetland suggested that the specific Hg methylation rate found was approximately an order of magnitude higher in biofilm cells than in planktonic cells. In order to investigate possible reasons for this observed difference, and to test if this phenomenon is observed in other strains, we conducted chloroform, fluroacetate and molybdate inhibition assays in both complete and incomplete-oxidizing SRB species (Desulfovibrio desulfuricans M8, Desulfococcus sp

  2. [Distribution and diversity of sulfate-reducing bacteria in a crude oil gathering and transferring system].

    PubMed

    Luo, Li; Liu, Yong-Jun; Wang, Xiao-Chang

    2010-09-01

    The distribution of sulfureted hydrogen (H2S) as well as sulfate-reducing bacteria (SRB) distribution and diversity in crude oil and oilfield production water samples from a oil gathering and transferring system in Changqing Oilfield of China were investigated by methylene blue colorimetric method, the most probable number technique and sequence analysis of the 16S rRNA gene, respectively. At the oil gathering and transferring system which from oil well through oil flowstation and then to oil comprehensive treatment station, the results showed that in oil samples, the content of H2S were 105.80, 99.70, and 24.57 mg x L(-1), respectively; and the count of SRB were 98, 300, and 680 CFU x100 mL(-1), respectively. In water samples, the content of H2S were 1.13, 2.80, and 3.49 mg x L(-1), respectively; and the count of SRB were 9 500, 40 000, and 76 000 CFU x 100 mL(-1), respectively. The abundance of SRB in the water samples is about 100 times than that in the crude-oil samples. High concentration of H2S in oil well inhibited the growth of SRB, thereby the count of SRB in oil well were small. With the reduction of H2S concentration, the actions of inhibition weakened and disappeared, then the number of SRB were gradual increase in the gathering and transferring system. For the initial concentration of H2S in water samples was low, and the number of SRB were large, then the content of H2S increased gradually with the number of SRB were increased. Sequence analysis of the 16S rRNA gene indicated that SRB related to Desulfovibrionaceae sp. and Desulfococcus sp. were detected in the water and crude oil samples, simultaneously. However, SRB related to Desulfomonile sp., Desulfotomaculum sp. and Desulfosarcina sp. were detected in the water samples but not in crude-oil samples. Abundance of SRB was increased due to the variation of environmental condition during the period of oil gathering and transferring process. PMID:21072940

  3. Biomarkers of sulfate reducing bacteria from a variety of different aged samples including a modern microbial mat

    NASA Astrophysics Data System (ADS)

    Pages, A.; Grice, K.; Lockhart, R.; Holman, A.; Melendez, I.; Van Kranendonk, M.; Jaraula, C.

    2011-12-01

    Most biomarkers present in sediments occur in only trace concentrations, trapped in kerogen or may be highly functionalised especially in recent sedimentary deposits making them difficult to chromatographically resolve, thus presenting considerable analytical challenges, especially for isotope studies. Innovative hydro (Hy) pyrolysis (Py) techniques are able to target or convert many of these compounds into free hydrocarbons more amenable to gas chromatography mass-spectrometry (GC-MS) and compound-specific isotope analysis (CSIA). HyPy has been applied to a modern layered smooth mat from Shark Bay, Western Australia. Saturate and aromatic fractions from different layers of the mat have been analysed by GC-MS and CSIA. After HyPy, an even-odd distribution of n-alkanes has been revealed as well as very long-chain n-alkanes up to n-C38. Stable carbon isotopic values of the n-alkanes indicated the presence of at least two bacterial communities. The short-chain n-alkanes were likely to be representative of a cyanobacteria community (δ13C, C15-C23, - 18 to -25 %VPDB) while the carbon isotopic values of the long-chain n-alkanes supported the presence of sulfate reducing bacteria (δ13C, C25-C33, - 30 to - 34 %VPDB). Long-chain fatty acids have been previously reported in sulfate reducing bacteria. It is hypothesised that this distribution and isotopic character representing sulfate reducing bacteria consortia may be preserved in the rock record. This hypothesis has been tested in Australian rocks: a Devonian carbonaceous concretion containing an exceptionally well preserved fossil invertebrate from the Canning Basin, Western Australia, a Paleoproterozoic sample (1.6 billion years old) from a lead-zinc ore deposit from the McArthur Basin, Northern Territories and a Paleoproterozoic chert (2.3 billion years old) from the Pilbara, Western Australia. Biomarkers of these samples showed a strong predominance of long-chain n-alkanes, up to n-C38 with an even-odd distribution

  4. Removal of sulfate and heavy metals by sulfate reducing bacteria in short-term bench scale upflow anaerobic packed bed reactor runs.

    PubMed

    Jong, Tony; Parry, David L

    2003-08-01

    Mildly acidic metal (Cu, Zn, Ni, Fe, Al and Mg), arsenic and sulfate contaminated waters were treated, over a 14 day period at 25 degrees C, in a bench-scale upflow anaerobic packed bed reactor filled with silica sand and employing a mixed population of sulfate-reducing bacteria (SRB). The activity of SRB increased the water pH from approximately 4.5 to 7.0, and enhanced the removal of sulfate and metals in comparison to controls not inoculated with SRB. Addition of organic substrate and sulfate at loading rates of 7.43 and 3.71 kg d(-1) m(-3), respectively, resulted in >82% reduction in sulfate concentration. The reactor removed more than 97.5% of the initial concentrations of Cu, Zn and Ni, while only >77.5% and >82% of As and Fe were removed, respectively. In contrast, Mg and Al levels remained unchanged during the whole treatment process. The removal patterns for Cu, Zn, Ni and Fe reflected the trend in their solubility for their respective metal sulfides, while As removal appeared to coincide with decreasing Cu, Zn, Ni and Fe concentrations, which suggests adsorption or concomitant precipitation with the other metal sulfides. PMID:12834731

  5. Detection and Quantification of Functional Genes of Cellulose- Degrading, Fermentative, and Sulfate-Reducing Bacteria and Methanogenic Archaea▿

    PubMed Central

    Pereyra, L. P.; Hiibel, S. R.; Prieto Riquelme, M. V.; Reardon, K. F.; Pruden, A.

    2010-01-01

    Cellulose degradation, fermentation, sulfate reduction, and methanogenesis are microbial processes that coexist in a variety of natural and engineered anaerobic environments. Compared to the study of 16S rRNA genes, the study of the genes encoding the enzymes responsible for these phylogenetically diverse functions is advantageous because it provides direct functional information. However, no methods are available for the broad quantification of these genes from uncultured microbes characteristic of complex environments. In this study, consensus degenerate hybrid oligonucleotide primers were designed and validated to amplify both sequenced and unsequenced glycoside hydrolase genes of cellulose-degrading bacteria, hydA genes of fermentative bacteria, dsrA genes of sulfate-reducing bacteria, and mcrA genes of methanogenic archaea. Specificity was verified in silico and by cloning and sequencing of PCR products obtained from an environmental sample characterized by the target functions. The primer pairs were further adapted to quantitative PCR (Q-PCR), and the method was demonstrated on samples obtained from two sulfate-reducing bioreactors treating mine drainage, one lignocellulose based and the other ethanol fed. As expected, the Q-PCR analysis revealed that the lignocellulose-based bioreactor contained higher numbers of cellulose degraders, fermenters, and methanogens, while the ethanol-fed bioreactor was enriched in sulfate reducers. The suite of primers developed represents a significant advance over prior work, which, for the most part, has targeted only pure cultures or has suffered from low specificity. Furthermore, ensuring the suitability of the primers for Q-PCR provided broad quantitative access to genes that drive critical anaerobic catalytic processes. PMID:20139321

  6. Competitive Oxidation of Volatile Fatty Acids by Sulfate- and Nitrate-Reducing Bacteria from an Oil Field in Argentina▿ †

    PubMed Central

    Grigoryan, Aleksandr A.; Cornish, Sabrina L.; Buziak, Brenton; Lin, Shiping; Cavallaro, Adriana; Arensdorf, Joseph J.; Voordouw, Gerrit

    2008-01-01

    Acetate, propionate, and butyrate, collectively referred to as volatile fatty acids (VFA), are considered among the most important electron donors for sulfate-reducing bacteria (SRB) and heterotrophic nitrate-reducing bacteria (hNRB) in oil fields. Samples obtained from a field in the Neuquén Basin, western Argentina, had significant activity of mesophilic SRB, hNRB, and nitrate-reducing, sulfide-oxidizing bacteria (NR-SOB). In microcosms, containing VFA (3 mM each) and excess sulfate, SRB first used propionate and butyrate for the production of acetate, which reached concentrations of up to 12 mM prior to being used as an electron donor for sulfate reduction. In contrast, hNRB used all three organic acids with similar kinetics, while reducing nitrate to nitrite and nitrogen. Transient inhibition of VFA-utilizing SRB was observed with 0.5 mM nitrite and permanent inhibition with concentrations of 1 mM or more. The addition of nitrate to medium flowing into an upflow, packed-bed bioreactor with an established VFA-oxidizing SRB consortium led to a spike of nitrite up to 3 mM. The nitrite-mediated inhibition of SRB led, in turn, to the transient accumulation of up to 13 mM of acetate. The complete utilization of nitrate and the incomplete utilization of VFA, especially propionate, and sulfate indicated that SRB remained partially inhibited. Hence, in addition to lower sulfide concentrations, an increase in the concentration of acetate in the presence of sulfate in waters produced from an oil field subjected to nitrate injection may indicate whether the treatment is successful. The microbial community composition in the bioreactor, as determined by culturing and culture-independent techniques, indicated shifts with an increasing fraction of nitrate. With VFA and sulfate, the SRB genera Desulfobotulus, Desulfotignum, and Desulfobacter as well as the sulfur-reducing Desulfuromonas and the NR-SOB Arcobacter were detected. With VFA and nitrate, Pseudomonas spp. were

  7. Quantitative real-time PCR analyses of sulfate-reducing bacteria in swine manure and the inhibitory effects of condensed tannins

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Odorous chemicals produced by anaerobic bacteria in stored swine manure are a nuisance and potential health hazard. One of the more odorous compounds is hydrogen sulfide (H2S), produced primarily by sulfate-reducing bacteria (SRB). However, little is known about these bacteria in stored swine manu...

  8. Genes for Uranium Bioremediation in the Anaerobic Sulfate-Reducing Bacteria

    SciTech Connect

    Wall, Judy D.

    2003-06-01

    Surprising results were obtained following an attempt to induce or derepress the machinery for U(VI) reduction by growing Desulfovibrio desulfuricans G20 in the presence of 1 mM uranyl acetate. G20 cells grown on lactate-sulfate medium amended with U(VI) reduced uranium at a slower rate than cells grown in the absence of this metal. When periplasmic extracts of these cells were prepared, Western analysis of the proteins revealed that the cytochrome c3 was absent. This observation has been further investigated.

  9. Desulfotomaculum spp. and related gram-positive sulfate-reducing bacteria in deep subsurface environments

    PubMed Central

    Aüllo, Thomas; Ranchou-Peyruse, Anthony; Ollivier, Bernard; Magot, Michel

    2013-01-01

    Gram-positive spore-forming sulfate reducers and particularly members of the genus Desulfotomaculum are commonly found in the subsurface biosphere by culture based and molecular approaches. Due to their metabolic versatility and their ability to persist as endospores. Desulfotomaculum spp. are well-adapted for colonizing environments through a slow sedimentation process. Because of their ability to grow autotrophically (H2/CO2) and produce sulfide or acetate, these microorganisms may play key roles in deep lithoautotrophic microbial communities. Available data about Desulfotomaculum spp. and related species from studies carried out from deep freshwater lakes, marine sediments, oligotrophic and organic rich deep geological settings are discussed in this review. PMID:24348471

  10. Oil Field Souring Control by Nitrate-Reducing Sulfurospirillum spp. That Outcompete Sulfate-Reducing Bacteria for Organic Electron Donors▿ †

    PubMed Central

    Hubert, Casey; Voordouw, Gerrit

    2007-01-01

    Nitrate injection into oil reservoirs can prevent and remediate souring, the production of hydrogen sulfide by sulfate-reducing bacteria (SRB). Nitrate stimulates nitrate-reducing, sulfide-oxidizing bacteria (NR-SOB) and heterotrophic nitrate-reducing bacteria (hNRB) that compete with SRB for degradable oil organics. Up-flow, packed-bed bioreactors inoculated with water produced from an oil field and injected with lactate, sulfate, and nitrate served as sources for isolating several NRB, including Sulfurospirillum and Thauera spp. The former coupled reduction of nitrate to nitrite and ammonia with oxidation of either lactate (hNRB activity) or sulfide (NR-SOB activity). Souring control in a bioreactor receiving 12.5 mM lactate and 6, 2, 0.75, or 0.013 mM sulfate always required injection of 10 mM nitrate, irrespective of the sulfate concentration. Community analysis revealed that at all but the lowest sulfate concentration (0.013 mM), significant SRB were present. At 0.013 mM sulfate, direct hNRB-mediated oxidation of lactate by nitrate appeared to be the dominant mechanism. The absence of significant SRB indicated that sulfur cycling does not occur at such low sulfate concentrations. The metabolically versatile Sulfurospirillum spp. were dominant when nitrate was present in the bioreactor. Analysis of cocultures of Desulfovibrio sp. strain Lac3, Lac6, or Lac15 and Sulfurospirillum sp. strain KW indicated its hNRB activity and ability to produce inhibitory concentrations of nitrite to be key factors for it to successfully outcompete oil field SRB. PMID:17308184

  11. Sulfur Isotropic Studies of Archean Slate and Graywacke from Northern Minnesota: Evidence for the Existence of Sulfate Reducing Bacteria

    NASA Technical Reports Server (NTRS)

    Ripley, E. M.; Nicol, D. L.

    1979-01-01

    Sulfur isotopic studies of pyrite from metasediments in the 2.6 b.y. old Deer Lake greenstone sequence, Minnesota, were conducted in order to evaluate the possible importance of sulfate reducing bacteria in sulfide formation. Pyrite occurs as ovules up to 2 cm in diameter within graphitic slates, and as fine disseminations in metagraywacke units. SEM studies indicate the pyrite is framboidal in morphology. Delta notation values of pyrite from the Deer Lake sediments range from -2.3 to 11.1 0/00, with a peak at approximately +2 o/oo. Isotopic data is consistent with either high temperature inorganic reduction of circulating seawater sulfate, or low temperature bacterial reduction. However, the lack of sulfide bands or massive occurrences in the sediments, the restriction of pyrite mineralization to the sediments, and the absence of evidence for hot spring activity suggest that a diagenetic origin of pyrite is more feasible. Sulfide in such an environment would be produced principally by the action of sulfate reducing bacteria.

  12. Iron sulfides and sulfur species produced at hematite surfaces in the presence of sulfate-reducing bacteria 1

    NASA Astrophysics Data System (ADS)

    Neal, Andrew L.; Techkarnjanaruk, Somkiet; Dohnalkova, Alice; McCready, David; Peyton, Brent M.; Geesey, Gill G.

    2001-01-01

    In the presence of sulfate-reducing bacteria ( Desulfovibrio desulfuricans) hematite (α-Fe 2O 3) dissolution is affected potentially by a combination of enzymatic (hydrogenase) reduction and hydrogen sulfide oxidation. As a consequence, ferrous ions are free to react with excess H 2S to form insoluble ferrous sulfides. X-ray photoelectron spectra indicate binding energies similar to ferrous sulfides having pyrrhotite-like structures (Fe2 p3/2 708.4 eV; S2 p3/2 161.5 eV). Other sulfur species identified at the surface include sulfate, sulfite and polysulfides. Thin film X-ray diffraction identifies a limited number of peaks, the principal one of which may be assigned to the hexagonal pyrrhotite (102) peak (d = 2.09 Å; 2θ = 43.22°), at the hematite surface within 3 months exposure to sulfate-reducing bacteria (SRB). High-resolution transmission electron microscopy identifies the presence of a hexagonal structure associated with observed crystallites. Although none of the analytical techniques employed provide unequivocal evidence as to the nature of the ferrous sulfide formed in the presence of SRB at hematite surfaces, we conclude from the available evidence that a pyrrhotite stiochiometry and structure is the best description of the sulfides we observe. Such ferrous sulfide production is inconsistent with previous reports in which mackinawite and greigite were products of biological sulfate reduction (Rickard 1969a; Herbert et al., 1998; Benning et al., 1999). The apparent differences in stoichiometry may be related to sulfide activity at the mineral surface, controlled in part by H 2S autooxidation in the presence of iron oxides. Due to the relative stability of pyrrhotite at low temperatures, ferrous sulfide dissolution is likely to be reduced compared to the more commonly observed products of SRB activity. Additionally, biogenic pyrrhotite formation will also have implications for geomagnetic field behavior of sediments.

  13. Genus- and group-specific hybridization probes for determinative and environmental studies of sulfate-reducing bacteria

    SciTech Connect

    Devereux, R.; Kane, M.D.; Winfrey, J.; Stahl, D.A.

    1992-01-01

    A set of six oligonucleotides, complementary to conserved tracts of 16S rRNA from phylogenetically-defined groups of sulfate-reducing bacteria, was characterized for use as hybridization probes in determinative and environmental microbiology. Four probes were genus specific and identified Desulfobacterium spp., Desulfobacter spp., Desulfobulbus spp., or Desulfovibrio spp. The other two probes encompassed more diverse assemblages. One probe was specific for the phylogenetic lineage composed of Desulfococcus multivorans, Desulfosarcina variabilis, and Desulfobotulus sapovorans. The remaining probe was specific for Desulfobacterium spp., Desulfobacter spp., D. multivorans, D. variabilis, and D. sapovorans. Temperature of dissociation was determined for each probe and the designed specificities of each were evaluated by hybridizations against closely related nontargeted species. In addition, each probe was screened by using a 'phylogrid' membrane which consisted of nucleic acids from sixtyfour non-targeted organisms representing a diverse collection of eukarya, archaea, and bacteria. The value of these probes to studies in environmental microbiology was evaluated by hybridizations to 16S rRNAs of sulfate-reducing bacteria present in marine sediments.

  14. Effectiveness of the bran media and bacteria inoculum treatments in increasing pH and reducing sulfur-total of acid sulfate soils

    NASA Astrophysics Data System (ADS)

    Taufieq, Nur Anny Suryaningsih; Rahim, Sahibin Abdul; Jamil, Habibah

    2013-11-01

    This study was carried out to determine the effectiveness ofsulfate reducing bacteria (SRB) in using bran as a source of food and energy, and to see the effectiveness of the bran media and bacteria inoculums treatments for pH and sulfur-total of acid sulfate reduction insoils. This study used two factors in group random designs with four treatments for bacteria inoculum of B1 (1%), B2 (5%), B3 (10%), B4 (15%) and two treatments for organic media (bran) of D1 (1:1) and D2 (1:19). Based on three replications, the combination resulted in a total of 24 treatments. Soil pH was measured using the Duddridge and Wainright method and determination of sulfate content in soil was conducted by the spectrophotometry method. The data obtained was analyzed for significance by Analysis of Variance and the Least Significant Difference Test. The pH of the initial acid sulfate soils ranged from 3 to 4 and the soil sulfur-total ranged from 1.4% to 10%. After mixing sulfate reducing bacteria with the bran mediaand incubated for four days, the pH of the acid sulfate soils increased from 3.67 to 4.20, while the soil sulfur-total contents had been reduced by 2.85% to 0.35%. This experiment has proven that an acid sulfate soil with low pH is a good growth medium for the sulfate reducing bacteria. The bestincubation period to achieve an effective bioremediation resultthrough sulfate percentage reduction by sulfate reducing bacteria was 10 days, while the optimum bran media dose was 1:19, and the bacteria inoculums dose was 10%.

  15. INFLUENCE OF THE SEAGRASS THALASSIA TESTUDINUM ON THE COMMUNITY COMPOSITION AND ACTIVITY OF SULFATE-REDUCING BACTERIA IN AN ESSENTIAL COAST MARINE HABITAT

    EPA Science Inventory

    Biogeochemical cycling of nutrients and sulfate reduction rates (SRR) were studied in relation to the community composition of sulfate-reducing bacteria SRB) in a Thalassia testudinum bed and in adjacent unvegetated areas. Sampling took place in Santa Rosa Sound, Pensacola, Flori...

  16. [Inhibition of the activity of sulfate-reducing bacteria in produced water from oil reservoir by nitrate].

    PubMed

    Yang, De-Yu; Zhang, Ying; Shi, Rong-Jiu; Han, Si-Qin; Li, Guang-Zhe; Li, Guo-Qiao; Zhao, Jin-Yi

    2014-01-01

    Growth and metabolic activity of sulfate-reducing bacteria (SRB) can result in souring of oil reservoirs, leading to various problems in aspects of environmental pollution and corrosion. Nitrate addition and management of nitrate-reducing bacteria (NRB) offer potential solutions to controlling souring in oil reservoirs. In this paper, a facultive chemolithotrophic NRB, designated as DNB-8, was isolated from the produced fluid of a water-flooded oil reservoir at Daqing oilfield. Then the efficacies and mechanisms of various concentrations of nitrate in combination with DNB-8 in the inhibition of the activity of SRB enriched culture were compared. Results showed that 1.0 mmol x L(-1) of nitrate or 0.45 mmol x L(-1) of nitrite inhibited the sulfate-reducing activity of SRB enrichments; the competitive reduction of nitrate by DNB-8 and the nitrite produced were responsible for the suppression. Besides, the SRB enrichment cultures showed a metabolic pathway of dissimilatory nitrate reduction to ammonium (DNRA) via nitrite. The SRB cultures could possibly alleviate the nitrite inhibition by DNRA when they were subjected to high-strength nitrate. PMID:24720222

  17. Genes for Uranium Bioremediation in the Anaerobic Sulfate-Reducing Bacteria: Desulfovibrio mutants with altered sensitivity to oxidative stress

    SciTech Connect

    Payne, Rayford B.; Ringbauer, Joseph A., Jr.; Wall, Judy D.

    2006-04-05

    Sulfate-reducing bacteria of the genus Desulfovibrio are ubiquitous in anaerobic environments such as groundwater, sediments, and the gastrointestinal tract of animals. Because of the ability of Desulfovibrio to reduce radionuclides and metals through both enzymatic and chemical means, they have been proposed as a means to bioremediate heavy metal contaminated sites. Although classically thought of as strict anaerobes, Desulfovibrio species are surprisingly aerotolerant. Our objective is to understand the response of Desulfovibrio to oxidative stress so that we may more effectively utilize them in bioremediation of heavy metals in mixed aerobic-anaerobic environments. The enzymes superoxide dismutase, superoxide reductase, catalase, and rubrerythrin have been shown by others to be involved in the detoxification of reactive oxygen species in Desulfovibrio. Some members of the genus Desulfovibrio can even reduce molecular oxygen to water via a membrane bound electron transport chain with the concomitant production of ATP, although their ability to grow with oxygen as the sole electron acceptor is still questioned.

  18. Genetics and Molecular Biology of Hydrogen Metabolism in Sulfate-Reducing Bacteria

    SciTech Connect

    Wall, Judy D.

    2014-12-23

    The degradation of our environment and the depletion of fossil fuels make the exploration of alternative fuels evermore imperative. Among the alternatives is biohydrogen which has high energy content by weight and produces only water when combusted. Considerable effort is being expended to develop photosynthetic systems -- algae, cyanobacteria, and anaerobic phototrophs -- for sustainable H2 production. While promising, this approach also has hurdles such as the harvesting of light in densely pigmented cultures that requires costly constant mixing and large areas for exposure to sunlight. Little attention is given to fermentative H2 generation. Thus understanding the microbial pathways to H2 evolution and metabolic processes competing for electrons is an essential foundation that may expand the variety of fuels that can be generated or provide alternative substrates for fine chemical production. We studied a widely found soil anaerobe of the class Deltaproteobacteria, a sulfate-reducing bacterium to determine the electron pathways used during the oxidation of substrates and the potential for hydrogen production.

  19. Molecular characterization of sulfate-reducing bacteria community in surface sediments from the adjacent area of Changjiang Estuary

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Zhen, Yu; Mi, Tiezhu; He, Hui; Yu, Zhigang

    2016-02-01

    Sulfate-reducing bacteria (SRB), which obtain energy from dissimilatory sulfate reduction, play a vital role in the carbon and sulfur cycles. The dissimilatory sulfite reductase (Dsr), catalyzing the last step in the sulfate reduction pathway, has been found in all known SRB that have been tested so far. In this study, the diversity of SRB was investigated in the surface sediments from the adjacent area of Changjiang Estuary by PCR amplification, cloning and sequencing of the dissimilatory sulfite reductase beta subunit gene ( dsrB). Based on dsrB clone libraries constructed in this study, diversified SRB were found, represented by 173 unique OTUs. Certain cloned sequences were associated with Desulfobacteraceae, Desulfobulbaceae, and a large fraction (60%) of novel sequences that have deeply branched groups in the dsrB tree, indicating that novel SRB inhabit the surface sediments. In addition, correlations of the SRB assemblages with environmental factors were analyzed by the linear model-based redundancy analysis (RDA). The result revealed that temperature, salinity and the content of TOC were most closely correlated with the SRB communities. More information on SRB community was obtained by applying the utility of UniFrac to published dsrB gene sequences from this study and other 9 different kinds of marine environments. The results demonstrated that there were highly similar SRB genotypes in the marine and estuarine sediments, and that geographic positions and environmental factors influenced the SRB community distribution.

  20. Distribution of iron- and sulfate-reducing bacteria across a coastal acid sulfate soil (CASS) environment: implications for passive bioremediation by tidal inundation

    PubMed Central

    Ling, Yu-Chen; Bush, Richard; Grice, Kliti; Tulipani, Svenja; Berwick, Lyndon; Moreau, John W.

    2015-01-01

    Coastal acid sulfate soils (CASS) constitute a serious and global environmental problem. Oxidation of iron sulfide minerals exposed to air generates sulfuric acid with consequently negative impacts on coastal and estuarine ecosystems. Tidal inundation represents one current treatment strategy for CASS, with the aim of neutralizing acidity by triggering microbial iron- and sulfate-reduction and inducing the precipitation of iron-sulfides. Although well-known functional guilds of bacteria drive these processes, their distributions within CASS environments, as well as their relationships to tidal cycling and the availability of nutrients and electron acceptors, are poorly understood. These factors will determine the long-term efficacy of “passive” CASS remediation strategies. Here we studied microbial community structure and functional guild distribution in sediment cores obtained from 10 depths ranging from 0 to 20 cm in three sites located in the supra-, inter- and sub-tidal segments, respectively, of a CASS-affected salt marsh (East Trinity, Cairns, Australia). Whole community 16S rRNA gene diversity within each site was assessed by 454 pyrotag sequencing and bioinformatic analyses in the context of local hydrological, geochemical, and lithological factors. The results illustrate spatial overlap, or close association, of iron-, and sulfate-reducing bacteria (SRB) in an environment rich in organic matter and controlled by parameters such as acidity, redox potential, degree of water saturation, and mineralization. The observed spatial distribution implies the need for empirical understanding of the timing, relative to tidal cycling, of various terminal electron-accepting processes that control acid generation and biogeochemical iron and sulfur cycling. PMID:26191042

  1. Distribution of iron- and sulfate-reducing bacteria across a coastal acid sulfate soil (CASS) environment: implications for passive bioremediation by tidal inundation.

    PubMed

    Ling, Yu-Chen; Bush, Richard; Grice, Kliti; Tulipani, Svenja; Berwick, Lyndon; Moreau, John W

    2015-01-01

    Coastal acid sulfate soils (CASS) constitute a serious and global environmental problem. Oxidation of iron sulfide minerals exposed to air generates sulfuric acid with consequently negative impacts on coastal and estuarine ecosystems. Tidal inundation represents one current treatment strategy for CASS, with the aim of neutralizing acidity by triggering microbial iron- and sulfate-reduction and inducing the precipitation of iron-sulfides. Although well-known functional guilds of bacteria drive these processes, their distributions within CASS environments, as well as their relationships to tidal cycling and the availability of nutrients and electron acceptors, are poorly understood. These factors will determine the long-term efficacy of "passive" CASS remediation strategies. Here we studied microbial community structure and functional guild distribution in sediment cores obtained from 10 depths ranging from 0 to 20 cm in three sites located in the supra-, inter- and sub-tidal segments, respectively, of a CASS-affected salt marsh (East Trinity, Cairns, Australia). Whole community 16S rRNA gene diversity within each site was assessed by 454 pyrotag sequencing and bioinformatic analyses in the context of local hydrological, geochemical, and lithological factors. The results illustrate spatial overlap, or close association, of iron-, and sulfate-reducing bacteria (SRB) in an environment rich in organic matter and controlled by parameters such as acidity, redox potential, degree of water saturation, and mineralization. The observed spatial distribution implies the need for empirical understanding of the timing, relative to tidal cycling, of various terminal electron-accepting processes that control acid generation and biogeochemical iron and sulfur cycling. PMID:26191042

  2. Reduction of Cr(VI) by a Consortium of Sulfate-Reducing Bacteria (SRB III)

    PubMed Central

    Fude, Li; Harris, Bob; Urrutia, Matilde M.; Beveridge, Terry J.

    1994-01-01

    A consortium of bacteria with tolerance to high concentrations of Cr(VI) (up to 2,500 ppm) and other toxic heavy metals has been obtained from metal-refinishing wastewaters in Chengdu, People's Republic of China. This consortium consists of a range of gram-positive and gram-negative rods and has the capacity to reduce Cr(VI) to Cr(III) as amorphous precipitates which are associated with the bacterial surfaces. An endospore-producing, gram-positive rod and a gram-negative rod accumulate the most metallic precipitates, and, over time, 80 to 95% of Cr can be removed from concentrations ranging from 50 to 2,000 ppm (0.96 to 38.45 mM). Kinetic studies revealed a first-order constant for Cr removal of 0.1518 h-1 for an initial concentration of 1,000 ppm (19.3 mM), and the sorption isothermal data could be interpreted by the Freundlich relationship. The sorption was not entirely due to a passive interaction with reactive sites on the bacterial surfaces since gamma-irradiated, killed cells could not immobilize as much metal. When U or Zn was added with the Cr, it was also removed and could even increase the total amount of Cr immobilized. The consortium was tolerant to small amounts of oxygen in the headspace of tubes, but active growth of the bacteria was a requirement for Cr immobilization through Cr(VI) reduction, resulting in the lowering of Eh. Our data suggest that the reduction was via H2S. This consortium has been named SRB III, and it may be useful for the bioremediation of fluid metal-refining wastes. Images PMID:16349253

  3. Improved Most-Probable-Number Method To Detect Sulfate-Reducing Bacteria with Natural Media and a Radiotracer

    PubMed Central

    Vester, Flemming; Ingvorsen, Kjeld

    1998-01-01

    A greatly improved most-probable-number (MPN) method for selective enumeration of sulfate-reducing bacteria (SRB) is described. The method is based on the use of natural media and radiolabeled sulfate (35SO42−). The natural media used consisted of anaerobically prepared sterilized sludge or sediment slurries obtained from sampling sites. The densities of SRB in sediment samples from Kysing Fjord (Denmark) and activated sludge were determined by using a normal MPN (N-MPN) method with synthetic cultivation media and a tracer MPN (T-MPN) method with natural media. The T-MPN method with natural media always yielded significantly higher (100- to 1,000-fold-higher) MPN values than the N-MPN method with synthetic media. The recovery of SRB from environmental samples was investigated by simultaneously measuring sulfate reduction rates (by a 35S-radiotracer method) and bacterial counts by using the T-MPN and N-MPN methods, respectively. When bacterial numbers estimated by the T-MPN method with natural media were used, specific sulfate reduction rates (qSO42−) of 10−14 to 10−13 mol of SO42− cell−1 day−1 were calculated, which is within the range of qSO42− values previously reported for pure cultures of SRB (10−15 to 10−14 mol of SO42− cell−1 day−1). qSO42− values calculated from N-MPN values obtained with synthetic media were several orders of magnitude higher (2 × 10−10 to 7 × 10−10 mol of SO42− cell−1 day−1), showing that viable counts of SRB were seriously underestimated when standard enumeration media were used. Our results demonstrate that the use of natural media results in significant improvements in estimates of the true numbers of SRB in environmental samples. PMID:9572939

  4. Stimulation of sulfate-reducing bacteria in lake water from a former open-pit mine through addition of organic wastes

    SciTech Connect

    Castro, J.M.; Wielinga, B.W.; Gannon, J.E.; Moore, J.N.

    1999-03-01

    A method to improve water quality in a lake occupying a former open-pit mine was evaluated in a laboratory-scale study. Untreated pit lake water contained high levels of sulfate, iron, and arsenic and was mildly acidic ({approximately} pH 6). Varying amounts of two locally available organic waste products were added to pit water and maintained in microcosms under anoxic conditions. In selected microcosms, populations of sulfate-reducing bacteria increased with time; sulfide was generated by sulfate reduction; sulfate, iron, and arsenic concentrations approached zero; and pH approached neutrality. Best results were obtained with intermediate amounts of waste potato skin.

  5. The Distribution of Thermophilic Sulfate-reducing Bacteria Along an Estuarine Gradient Reveals Multiple Origins of Endospores in Estuarine Sediments

    NASA Astrophysics Data System (ADS)

    Bell, E.

    2015-12-01

    Cold marine sediments harbour inactive spores of thermophilic bacteria. These misplaced thermophiles are genetically similar to microorganisms detected in deep biosphere environments, leading to the hypothesis that seabed fluid flow transports thermophiles out of warm subsurface environments and into the ocean. Estuaries form the transition between the marine and the terrestrial biosphere and are influenced by tidal currents, surface run-off and groundwater seepage. Endospores from thermophilic bacteria present in estuarine sediments could therefore originate from a number of sources that may influence the estuary differently. We have therefore tested the hypothesis that this will lead to a gradient in the composition of thermophilic endospore populations in estuarine sediments. The distribution of thermophilic spore-forming sulfate-reducing bacteria along an estuarine gradient from freshwater (River Tyne, UK) to marine (North Sea) was investigated. Microbial community analysis by 16S rRNA gene amplicon sequencing revealed changes in the thermophilic population enriched at different locations within the estuary. Certain species were only detected at the marine end, highlighting possible links to deep marine biosphere habitats such as oil reservoirs that harbour closely related Desulfotomaculum spp. Conversely, other taxa were predominantly observed in the freshwater reaches of the estuary indicating dispersal from an upstream or terrestrial source. Different endospore populations were enriched dependent on incubation temperature and spore heat-resistance. Microcosms incubated at 50, 60 or 70°C showed a shift in the dominant species of Desulfotomaculum enriched as the temperature increased. Microcosms triple-autoclaved at 121°C prior to incubation still showed rapid and reproducible sulfate-reduction and some Desulfotomaculum spp. remained active after autoclaving at 130°C. These results show that temperature physiology and biogeographic patterns can be used to

  6. USE OF HYDROGEN RESPIROMETRY TO DETERMINE METAL TOXICITY TO SULFATE REDUCING BACTERIA

    EPA Science Inventory

    Acid mine drainage (AMD), an acidic metal-bearing wastewater poses a severe pollution problem attributed to post-mining activities. The metals (metal sulfates) encountered in AMD and considered of concern for risk assessment are: arsenic, cadmium, aluminum, manganese, iron, zinc ...

  7. Enhanced performance of sulfate reducing bacteria based biocathode using stainless steel mesh on activated carbon fabric electrode.

    PubMed

    Sharma, Mohita; Jain, Pratiksha; Varanasi, Jhansi L; Lal, Banwari; Rodríguez, Jorge; Lema, Juan M; Sarma, Priyangshu M

    2013-12-01

    An anoxic biocathode was developed using sulfate-reducing bacteria (SRB) consortium on activated carbon fabric (ACF) and the effect of stainless steel (SS) mesh as additional current collector was investigated. Improved performance of biocathode was observed with SS mesh leading to nearly five folds increase in power density (from 4.79 to 23.11 mW/m(2)) and threefolds increase in current density (from 75 to 250 mA/m(2)). Enhanced redox currents and lower Tafel slopes observed from cyclic voltammograms of ACF with SS mesh indicated the positive role of uniform electron collecting points. Differential pulse voltammetry technique was employed as an additional tool to assess the redox carriers involved in bioelectrochemical reactions. SRB biocathode was also tested for reduction of volatile fatty acids (VFA) present in the fermentation effluent stream and the results indicated the possibility of integration of this system with anaerobic fermentation for efficient product recovery. PMID:24161648

  8. Diverse sulfate-reducing bacteria of the Desulfosarcina/Desulfococcus clade are the key alkane degraders at marine seeps

    PubMed Central

    Kleindienst, Sara; Herbst, Florian-Alexander; Stagars, Marion; von Netzer, Frederick; von Bergen, Martin; Seifert, Jana; Peplies, Jörg; Amann, Rudolf; Musat, Florin; Lueders, Tillmann; Knittel, Katrin

    2014-01-01

    Biogeochemical and microbiological data indicate that the anaerobic oxidation of non-methane hydrocarbons by sulfate-reducing bacteria (SRB) has an important role in carbon and sulfur cycling at marine seeps. Yet, little is known about the bacterial hydrocarbon degraders active in situ. Here, we provide the link between previous biogeochemical measurements and the cultivation of degraders by direct identification of SRB responsible for butane and dodecane degradation in complex on-site microbiota. Two contrasting seep sediments from Mediterranean Amon mud volcano and Guaymas Basin (Gulf of California) were incubated with 13C-labeled butane or dodecane under sulfate-reducing conditions and analyzed via complementary stable isotope probing (SIP) techniques. Using DNA- and rRNA-SIP, we identified four specialized clades of alkane oxidizers within Desulfobacteraceae to be distinctively active in oxidation of short- and long-chain alkanes. All clades belong to the Desulfosarcina/Desulfococcus (DSS) clade, substantiating the crucial role of these bacteria in anaerobic hydrocarbon degradation at marine seeps. The identification of key enzymes of anaerobic alkane degradation, subsequent β-oxidation and the reverse Wood–Ljungdahl pathway for complete substrate oxidation by protein-SIP further corroborated the importance of the DSS clade and indicated that biochemical pathways, analog to those discovered in the laboratory, are of great relevance for natural settings. The high diversity within identified subclades together with their capability to initiate alkane degradation and growth within days to weeks after substrate amendment suggest an overlooked potential of marine benthic microbiota to react to natural changes in seepage, as well as to massive hydrocarbon input, for example, as encountered during anthropogenic oil spills. PMID:24722631

  9. Diverse sulfate-reducing bacteria of the Desulfosarcina/Desulfococcus clade are the key alkane degraders at marine seeps.

    PubMed

    Kleindienst, Sara; Herbst, Florian-Alexander; Stagars, Marion; von Netzer, Frederick; von Bergen, Martin; Seifert, Jana; Peplies, Jörg; Amann, Rudolf; Musat, Florin; Lueders, Tillmann; Knittel, Katrin

    2014-10-01

    Biogeochemical and microbiological data indicate that the anaerobic oxidation of non-methane hydrocarbons by sulfate-reducing bacteria (SRB) has an important role in carbon and sulfur cycling at marine seeps. Yet, little is known about the bacterial hydrocarbon degraders active in situ. Here, we provide the link between previous biogeochemical measurements and the cultivation of degraders by direct identification of SRB responsible for butane and dodecane degradation in complex on-site microbiota. Two contrasting seep sediments from Mediterranean Amon mud volcano and Guaymas Basin (Gulf of California) were incubated with (13)C-labeled butane or dodecane under sulfate-reducing conditions and analyzed via complementary stable isotope probing (SIP) techniques. Using DNA- and rRNA-SIP, we identified four specialized clades of alkane oxidizers within Desulfobacteraceae to be distinctively active in oxidation of short- and long-chain alkanes. All clades belong to the Desulfosarcina/Desulfococcus (DSS) clade, substantiating the crucial role of these bacteria in anaerobic hydrocarbon degradation at marine seeps. The identification of key enzymes of anaerobic alkane degradation, subsequent β-oxidation and the reverse Wood-Ljungdahl pathway for complete substrate oxidation by protein-SIP further corroborated the importance of the DSS clade and indicated that biochemical pathways, analog to those discovered in the laboratory, are of great relevance for natural settings. The high diversity within identified subclades together with their capability to initiate alkane degradation and growth within days to weeks after substrate amendment suggest an overlooked potential of marine benthic microbiota to react to natural changes in seepage, as well as to massive hydrocarbon input, for example, as encountered during anthropogenic oil spills. PMID:24722631

  10. Apparent Minimum Free Energy Requirements for Methanogenic Archaea and Sulfate-Reducing Bacteria in an Anoxic Marine Sediment

    NASA Technical Reports Server (NTRS)

    Hoehler, Tori M.; Alperin, Marc J.; Albert, Daniel B.; Martens, Christopher S.; DeVincenzi, Don (Technical Monitor)

    2000-01-01

    Among the most fundamental constraints governing the distribution of microorganisms in the environment is the availability of chemical energy at biologically useful levels. To assess the minimum free energy yield that can support microbial metabolism in situ, we examined the thermodynamics of H2-consuming processes in anoxic sediments from Cape Lookout Bight, NC, USA. Depth distributions of H2 partial pressure, along with a suite of relevant concentration data, were determined in sediment cores collected in November (at 14.5 C) and August (at 27 C) and used to calculate free energy yields for methanogenesis and sulfate reduction. At both times of year, and for both processes, free energy yields gradually decreased (became less negative) with depth before reaching an apparent asymptote. Sulfate reducing bacteria exhibited an asymptote of -19.1 +/- 1.7 kj(mol SO4(2-)(sup -1) while methanogenic archaea were apparently supported by energy yields as small as -10.6 +/- 0.7 kj(mol CH4)(sup -1).

  11. Acid-Tolerant Sulfate-Reducing Bacteria Play a Major Role in Iron Cycling in Acidic Iron Rich Sediments

    NASA Astrophysics Data System (ADS)

    Enright, K. A.; Moreau, J. W.

    2008-12-01

    Climate change drives drying and acidification of many rivers and lakes. Abundant sedimentary iron in these systems oxidizes chemically and biologically to form iron-ox(yhydrox)ide crusts and "hardpans". Given generally high sulfate concentrations, the mobilization and cycling of iron in these environments can be strongly influenced by bacterial sulfate reduction. Sulfate-reducing bacteria (SRB) induce reductive dissolution of oxidized iron phases by producing the reductant bisulfide as a metabolic product. These environmentally ubiquitous microbes also recycle much of the fixed carbon in sediment-hosted microbial mat communities. With prevalent drying, the buffering capacity for protons liberated from iron oxidation is exceeded, and the activity of sulfate-reducers is restricted to those species capable of tolerating low pH (and generally highly saline, i.e. sulfate-rich) conditions. These species will sustain the recycling of iron from more crystalline phases to more bioavailable species, as well as act as the only source of bisulfide for photosynthesizing microbial communities. The phylogeny and physiology of acid-tolerant SRB is therefore important to Fe, S and C cycling in iron-rich sedimentary environments, particularly those on a geochemical trajectory towards acidification. Previous studies have shown that these SRB species tend to be highly novel. We studied two distinct environments along a geochemical continuum towards acidification. In both settings, iron redox transformations exert a major, if not controlling, influence on reduction potential. An acidified, iron- rich tidal marsh receiving acid-mine drainage (San Francisco Bay, CA, USA) contained abundant textural evidence for reductive dissolution of Fe(III) in sediments with pH values varying from 2.4 - 3.8. From these sediments, full-length novel dsrAB gene sequences from acid-tolerant SRB were recovered, and sulfur isotope profiles reflected biological fractionation of sulfur under even the most

  12. Influence of season and plant species on the abundance and diversity of sulfate reducing bacteria and ammonia oxidizing bacteria in constructed wetland microcosms.

    PubMed

    Faulwetter, Jennifer L; Burr, Mark D; Parker, Albert E; Stein, Otto R; Camper, Anne K

    2013-01-01

    Constructed wetlands offer an effective means for treatment of wastewater from a variety of sources. An understanding of the microbial ecology controlling nitrogen, carbon and sulfur cycles in constructed wetlands has been identified as the greatest gap for optimizing performance of these promising treatment systems. It is suspected that operational factors such as plant types and hydraulic operation influence the subsurface wetland environment, especially redox, and that the observed variation in effluent quality is due to shifts in the microbial populations and/or their activity. This study investigated the biofilm associated sulfate reducing bacteria and ammonia oxidizing bacteria (using the dsrB and amoA genes, respectively) by examining a variety of surfaces within a model wetland (gravel, thick roots, fine roots, effluent), and the changes in activity (gene abundance) of these functional groups as influenced by plant species and season. Molecular techniques were used including quantitative PCR and denaturing gradient gel electrophoresis (DGGE), both with and without propidium monoazide (PMA) treatment. PMA treatment is a method for excluding from further analysis those cells with compromised membranes. Rigorous statistical analysis showed an interaction between the abundance of these two functional groups with the type of plant and season (p < 0.05). The richness of the sulfate reducing bacterial community, as indicated by DGGE profiles, increased in planted vs. unplanted microcosms. For ammonia oxidizing bacteria, season had the greatest impact on gene abundance and diversity (higher in summer than in winter). Overall, the primary influence of plant presence is believed to be related to root oxygen loss and its effect on rhizosphere redox. PMID:22961363

  13. Kinetic properties of adenosine triphosphate sulfurylase of intestinal sulfate-reducing bacteria.

    PubMed

    Kushkevych, I V; Antonyak, H L; Bartoš, M

    2014-01-01

    The investigation of specific activity of ATP sulfurylase and kinetic properties of the enzyme in cell-free extracts of intestinal bacterial strains Desulfovibrio piger Vib-7 and Desulfomicrobium sp. Rod-9 is presented. The microbiological, biochemical, biophysical and statistical methods were used in the work. The optimal temperature (35°C) and pH 8.0-8.5 for enzyme reaction were determined. An analysis of kinetic properties of ATP sulfurylase has been carried out. Initial (instantaneous) reaction velocity (V0), maximum amount of the product of reaction (Pmax), the reaction time (half saturation period, τ) and maximum velocity of the ATP sulfurylase reaction (Vmax) have been defined. Michaelis constants (Km(Sulfate), Km(ATP), Km(APS), and Km(Pyrophosphate)) of the enzyme reaction were demonstrated for both D. piger Vib-7 and Desulfomicrobium sp. Rod-9 intestinal bacterial strains. PMID:25816613

  14. Practical applications of sulfate-reducing bacteria to control acid mine drainage at the Lilly/Orphan Boy Mine near Elliston, Montana

    SciTech Connect

    Canty, M.

    1994-12-31

    The overall purpose of this document is to provide a detailed technical description of a technology, biological sulfate reduction, which is being demonstrated under the Mine Waste Technology Pilot Program, and provide the technology evaluation process undertaken to select this technology for demonstration. In addition, this document will link the use of the selected technology to an application at a specific site. The purpose of this project is to develop technical information on the ability of biological sulfate reduction to slow the process of acid generation and, thus, improve water quality at a remote mine site. Several technologies are screened for their potential to treat acid mine water and to function as a source control for a specific acid-generating situation: a mine shaft and associated underground workings flooded with acid mine water and discharging a small flow from a mine opening. The preferred technology is the use of biological sulfate reduction. Sulfate-reducing bacteria are capable of reducing sulfate to sulfide, as well as increasing the pH and alkalinity of water affected by acid generation. Soluble sulfide reacts with the soluble metals in solution to form insoluble metal sulfides. The environment needed for efficient sulfate-reducing bacteria growth decreases acid production by reducing the dissolved oxygen in water and increasing pH. A detailed technical description of the sulfate-reducing bacteria technology, based on an extensive review of the technical literature, is presented. The field demonstration of this technology to be performed at the Lilly/Orphan Boy Mine is also described. Finally, additional in situ applications of biological sulfate reduction are presented.

  15. Gene Expression Correlates with Process Rates Quantified for Sulfate- and Fe(III)-Reducing Bacteria in U(VI)-Contaminated Sediments

    PubMed Central

    Akob, Denise M.; Lee, Sang Hyon; Sheth, Mili; Küsel, Kirsten; Watson, David B.; Palumbo, Anthony V.; Kostka, Joel E.; Chin, Kuk-Jeong

    2012-01-01

    Though iron- and sulfate-reducing bacteria are well known for mediating uranium(VI) reduction in contaminated subsurface environments, quantifying the in situ activity of the microbial groups responsible remains a challenge. The objective of this study was to demonstrate the use of quantitative molecular tools that target mRNA transcripts of key genes related to Fe(III) and sulfate reduction pathways in order to monitor these processes during in situ U(VI) remediation in the subsurface. Expression of the Geobacteraceae-specific citrate synthase gene (gltA) and the dissimilatory (bi)sulfite reductase gene (dsrA), were correlated with the activity of iron- or sulfate-reducing microorganisms, respectively, under stimulated bioremediation conditions in microcosms of sediments sampled from the U.S. Department of Energy’s Oak Ridge Integrated Field Research Challenge (OR-IFRC) site at Oak Ridge, TN, USA. In addition, Geobacteraceae-specific gltA and dsrA transcript levels were determined in parallel with the predominant electron acceptors present in moderately and highly contaminated subsurface sediments from the OR-IFRC. Phylogenetic analysis of the cDNA generated from dsrA mRNA, sulfate-reducing bacteria-specific 16S rRNA, and gltA mRNA identified activity of specific microbial groups. Active sulfate reducers were members of the Desulfovibrio, Desulfobacterium, and Desulfotomaculum genera. Members of the subsurface Geobacter clade, closely related to uranium-reducing Geobacter uraniireducens and Geobacter daltonii, were the metabolically active iron-reducers in biostimulated microcosms and in situ core samples. Direct correlation of transcripts and process rates demonstrated evidence of competition between the functional guilds in subsurface sediments. We further showed that active populations of Fe(III)-reducing bacteria and sulfate-reducing bacteria are present in OR-IFRC sediments and are good potential targets for in situ bioremediation. PMID:22908009

  16. Growth of Anaerobic Methane-Oxidizing Archaea and Sulfate-Reducing Bacteria in a High-Pressure Membrane Capsule Bioreactor

    PubMed Central

    Gieteling, Jarno; Widjaja-Greefkes, H. C. Aura; Plugge, Caroline M.; Stams, Alfons J. M.; Lens, Piet N. L.; Meulepas, Roel J. W.

    2014-01-01

    Communities of anaerobic methane-oxidizing archaea (ANME) and sulfate-reducing bacteria (SRB) grow slowly, which limits the ability to perform physiological studies. High methane partial pressure was previously successfully applied to stimulate growth, but it is not clear how different ANME subtypes and associated SRB are affected by it. Here, we report on the growth of ANME-SRB in a membrane capsule bioreactor inoculated with Eckernförde Bay sediment that combines high-pressure incubation (10.1 MPa methane) and thorough mixing (100 rpm) with complete cell retention by a 0.2-μm-pore-size membrane. The results were compared to previously obtained data from an ambient-pressure (0.101 MPa methane) bioreactor inoculated with the same sediment. The rates of oxidation of labeled methane were not higher at 10.1 MPa, likely because measurements were done at ambient pressure. The subtype ANME-2a/b was abundant in both reactors, but subtype ANME-2c was enriched only at 10.1 MPa. SRB at 10.1 MPa mainly belonged to the SEEP-SRB2 and Eel-1 groups and the Desulfuromonadales and not to the typically found SEEP-SRB1 group. The increase of ANME-2a/b occurred in parallel with the increase of SEEP-SRB2, which was previously found to be associated only with ANME-2c. Our results imply that the syntrophic association is flexible and that methane pressure and sulfide concentration influence the growth of different ANME-SRB consortia. We also studied the effect of elevated methane pressure on methane production and oxidation by a mixture of methanogenic and sulfate-reducing sludge. Here, methane oxidation rates decreased and were not coupled to sulfide production, indicating trace methane oxidation during net methanogenesis and not anaerobic methane oxidation, even at a high methane partial pressure. PMID:25501484

  17. Growth of anaerobic methane-oxidizing archaea and sulfate-reducing bacteria in a high-pressure membrane capsule bioreactor.

    PubMed

    Timmers, Peer H A; Gieteling, Jarno; Widjaja-Greefkes, H C Aura; Plugge, Caroline M; Stams, Alfons J M; Lens, Piet N L; Meulepas, Roel J W

    2015-02-01

    Communities of anaerobic methane-oxidizing archaea (ANME) and sulfate-reducing bacteria (SRB) grow slowly, which limits the ability to perform physiological studies. High methane partial pressure was previously successfully applied to stimulate growth, but it is not clear how different ANME subtypes and associated SRB are affected by it. Here, we report on the growth of ANME-SRB in a membrane capsule bioreactor inoculated with Eckernförde Bay sediment that combines high-pressure incubation (10.1 MPa methane) and thorough mixing (100 rpm) with complete cell retention by a 0.2-m-pore-size membrane. The results were compared to previously obtained data from an ambient-pressure (0.101 MPa methane) bioreactor inoculated with the same sediment. The rates of oxidation of labeled methane were not higher at 10.1 MPa, likely because measurements were done at ambient pressure. The subtype ANME-2a/b was abundant in both reactors, but subtype ANME-2c was enriched only at 10.1 MPa. SRB at 10.1 MPa mainly belonged to the SEEP-SRB2 and Eel-1 groups and the Desulfuromonadales and not to the typically found SEEP-SRB1 group. The increase of ANME-2a/b occurred in parallel with the increase of SEEP-SRB2, which was previously found to be associated only with ANME-2c. Our results imply that the syntrophic association is flexible and that methane pressure and sulfide concentration influence the growth of different ANME-SRB consortia. We also studied the effect of elevated methane pressure on methane production and oxidation by a mixture of methanogenic and sulfate-reducing sludge. Here, methane oxidation rates decreased and were not coupled to sulfide production, indicating trace methane oxidation during net methanogenesis and not anaerobic methane oxidation, even at a high methane partial pressure. PMID:25501484

  18. Fractionation of Mercury Stable Isotopes during Microbial Methylmercury Production by Iron- and Sulfate-Reducing Bacteria.

    PubMed

    Janssen, Sarah E; Schaefer, Jeffra K; Barkay, Tamar; Reinfelder, John R

    2016-08-01

    The biological production of monomethylmercury (MeHg) in soils and sediments is an important factor controlling mercury (Hg) accumulation in aquatic and terrestrial food webs. In this study we examined the fractionation of Hg stable isotopes during Hg methylation in nongrowing cultures of the anaerobic bacteria Geobacter sulfurreducens PCA and Desulfovibrio desulfuricans ND132. Both organisms showed mass-dependent, but no mass-independent fractionation of Hg stable isotopes during Hg methylation. Despite differences in methylation rates, the two bacteria had similar Hg fractionation factors (αr/p = 1.0009 and 1.0011, respectively). Unexpectedly, δ(202)Hg values of MeHg for both organisms were 0.4‰ higher than the value of initial inorganic Hg after about 35% of inorganic Hg had been methylated. These results indicate that a (202)Hg-enriched pool of inorganic Hg was preferentially utilized as a substrate for methylation by these organisms, but that multiple intra- and/or extracellular pools supplied inorganic Hg for biological methylation. Understanding the controls of the Hg stable isotopic composition of microbially produced MeHg is important to identifying bioavailable Hg in natural systems and the interpretation of Hg stable isotopes in aquatic food webs. PMID:27392249

  19. Distinctive Oxidative Stress Responses to Hydrogen Peroxide in Sulfate Reducing Bacteria Desulfovibrio vulgaris Hildenborough

    SciTech Connect

    Zhou, Aifen; He, Zhili; Redding, A.M.; Mukhopadhyay, Aindrila; Hemme, Christopher L.; Joachimiak, Marcin P.; Bender, Kelly S.; Keasling, Jay D.; Stahl, David A.; Fields, Matthew W.; Hazen, Terry C.; Arkin, Adam P.; Wall, Judy D.; Zhou, Jizhong

    2009-01-01

    Response of Desulfovibrio vulgaris Hildenborough to hydrogen peroxide (H2O2, 1 mM) was investigated with transcriptomic, proteomic and genetic approaches. Microarray data demonstrated that gene expression was extensively affected by H2O2 with the response peaking at 120 min after H2O2 treatment. Genes affected include those involved with energy production, sulfate reduction, ribosomal structure and translation, H2O2 scavenging, posttranslational modification and DNA repair as evidenced by gene coexpression networks generated via a random matrix-theory based approach. Data from this study support the hypothesis that both PerR and Fur play important roles in H2O2-induced oxidative stress response. First, both PerR and Fur regulon genes were significantly up-regulated. Second, predicted PerR regulon genes ahpC and rbr2 were derepressedin Delta PerR and Delta Fur mutants and induction of neither gene was observed in both Delta PerR and Delta Fur when challenged with peroxide, suggesting possible overlap of these regulons. Third, both Delta PerR and Delta Fur appeared to be more tolerant of H2O2 as measured by optical density. Forth, proteomics data suggested de-repression of Fur during the oxidative stress response. In terms of the intracellular enzymatic H2O2 scavenging, gene expression data suggested that Rdl and Rbr2 may play major roles in the detoxification of H2O2. In addition, induction of thioredoxin reductase and thioredoxin appeared to be independent of PerR and Fur. Considering all data together, D. vulgaris employed a distinctive stress resistance mechanism to defend against increased cellular H2O2, and the temporal gene expression changes were consistent with the slowdown of cell growth at the onset of oxidative stress.

  20. Electron-bifurcating transhydrogenase is central to hydrogen isotope fractionation during lipid biosynthesis in sulfate reducing bacteria

    NASA Astrophysics Data System (ADS)

    Leavitt, W.; Flynn, T. M.; Suess, M.; Bradley, A. S.

    2015-12-01

    A significant range in microbial lipid 2H/1H ratios is observed in modern marine sediments [Li et al. 2009. GCA]. The magnitude of hydrogen isotope fractionation between microbial lipids and growth water (2ɛlipid-H2O) is hypothesized to relate to the central carbon and energy metabolism [Zhang et al. 2009. PNAS]. These observations have raised the intriguing possibility for culture independent identification of the dominant metabolic pathways operating in environments critical to the geological record. One such metabolism we would like to track for its global significance in sedimentary carbon cycling is bacterial sulfate reduction [Jørgensen. 1982. Nature]. To-date, heterotrophic sulfate reducing bacteria (SRB) have been observed to produce lipids that are depleted in fatty acid H-isotope composition, relative to growth water (2ɛlipid-H2O ~ -125 to -175 ‰), with experiments on different substrates yielding little variability [Campbell et al. 2009. GCA; Osburn. 2013; Dawson et al. 2015. Geobiology]. In stark contrast, aerobic heterotrophs show a wide range in fractionations (2ɛlipid-H2O ~ +300 to -125‰) which seems to scale with the route cellular carbon metabolism [Zhang et al. 2009. PNAS; Heinzelmann et al. 2015. Front Microbio]. Recent work in aerobic methylotrophs [Bradley et al. 2014. AGU] implicates transhydrogenase (TH) activity as a critical control on 2ɛlipid-H2O. This work suggests a specific driving mechanism for this range in fractionation is the ratio of intracellular NADPH/NADH, and more fundamentally, the intracellular redox state. In SRB a key component of energy metabolism is the activity of electron-bifurcating TH [Price et al. 2014. Front Microbio], for which a recent transposon mutant library has generated a number of knockouts in the target gene [Kuehl et al. 2014. mBio] in the model organism Desulfovibrio alaskensis strain G20. In this study we compare growth rates, fatty acid concentrations and 2ɛlipid-H2O from wild type and TH

  1. ACUTE TOXICITY OF HEAVY METALS TO ACETATE-UTILIZING MIXED CULTURES OF SULFATE-REDUCING BACTERIA: EC100 AND EC50

    EPA Science Inventory

    Acid mine drainage (AMD) from abandoned mines and acid mine pitlakes is an important environmental contaminant concern and usually contains appreciable concentrations of heavy metals. Since sulfate-reducing bacteria (SRB) are involved in the treatment of AMD, knowledge of acute m...

  2. Effect of dietary inorganic sulfur level on growth performance, fecal composition, and measures of inflammation and sulfate-reducing bacteria in the intestine of growing pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two experiments were conducted to investigate the impact of dietary inorganic S on growth performance, markers of intestinal inflammation, fecal composition, and the presence of sulfate-reducing bacteria (SRB). In Exp. 1, pigs (n = 42; 13.8 kg) were fed diets formulated to contain either 2,300 or 2,...

  3. Development and Comparison of SYBR Green Quantitative Real-time PCR Assays for Detection and Enumeration of Sulfate-reducing Bacteria in Stored Swine Manure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A quantitative real-time polymerase chain reaction (PCR) assay for sulfate-reducing bacteria (SRB) was developed that targeted the dissimilatory sulfite reductase gene (dsrA). Degenerate primer sets were developed to detect three different groups of SRB in stored swine manure using a SYBR Green qua...

  4. COMPARISON OF PHYLOGENETIC RELATIONSHIPS BASED ON PHOSPHOLIPID FATTY ACID PROFILES AND RIBOSOMAL RNA SEQUENCE SIMILARITIES AMONG DISSIMILATORY SULFATE-REDUCING BACTERIA

    EPA Science Inventory

    Twenty-five isolates of dissimilatory sulfate-reducing bacteria were clustered based on similarity analysis of their phospholipid ester-linked fatty acids (PLFA). f these, twenty-three showed the phylogenetic relationships based on the sequence similarity of their 16S rRNA direct...

  5. [Treating Cr(VI)-containing wastewater by a consortium of sulfate reducing bacteria and copper-iron bimetallic particles].

    PubMed

    He, Qi-Zhi; Chen, Hui; Wang, Dan; Li, Hua; Ding, Xing-Hu; Deng, Le

    2011-07-01

    Copper-iron bimetallic particles were prepared by chemical precipitation technique. Under the help of the particles Cr(VI)-containing wastewater was well treated by a consortium of sulfate reducing bacteria, which were enriched from industrial wastewater and acclimatized to tolerant to high concentrations of Cr(VI). SRB-Cu/Fe system, traditional SRB system and Cu/Fe system were experimented in the batch bioreactor, respectively. It is demonstrated that SRB-Cu/Fe bimetallic system perform much better than traditional SRB system or copper-iron bimetallic. The acclimation period of SRB was significantly reduced and the inhibiting concentration of Cr(VI) of SRB was also greatly increased by approximately 200% (from 100 mg x L(-1) to 300 mg x L(-1)). Under the conditions of Cr(VI) 300 mg x L(-1), Q(Cu)/Fe 7.5%, pH 5.0-8.0, the concentration of total chromium was less than 0.512 mg/L, Cr(VI) less than 0.071 mg, Cu next to zero after 48 h treatment. Having biological, chemical advantages and high efficiency, the novel SRB-Cu/Fe system should have the broad application prospects in industrial wastewater. PMID:21922821

  6. Assessing the Role of Iron Sulfides in the Long Term Sequestration of Uranium by Sulfate-Reducing Bacteria

    SciTech Connect

    Hayes, Kim F.; Bi, Yuqiang; Carpenter, Julian; Hyng, Sung Pil; Rittmann, Bruce E.; Zhou, Chen; Vannela, Raveender; Davis, James A.

    2014-01-01

    This overarching aim of this project was to identify the role of biogenic and synthetic iron-sulfide minerals in the long-term sequestration of reduced U(IV) formed under sulfate-reducing conditions when subjected to re-oxidizing conditions. The work reported herein was achieved through the collaborative research effort conducted at Arizona State University (ASU) and the University of Michigan (UM). Research at ASU, focused on the biogenesis aspects, examined the biogeochemical bases for iron-sulfide production by Desulfovibrio vulgaris, a Gram-negative bacterium that is one of the most-studied strains of sulfate-reducing bacteria. A series of experimental studies were performed to investigate comprehensively important metabolic and environmental factors that affect the rates of sulfate reduction and iron-sulfide precipitation, the mineralogical characteristics of the iron sulfides, and how uranium is reduced or co-reduced by D. vulagaris. FeS production studies revealed that controlling the pH affected the growth of D. vulgaris and strongly influenced the formation and growth of FeS solids. In particular, lower pH produced larger-sized mackinawite (Fe1+xS). Greater accumulation of free sulfide, from more sulfate reduction by D. vulgaris, also led to larger-sized mackinawite and stimulated mackinawite transformation to greigite (Fe3S4) when the free sulfide concentration was 29.3 mM. On the other hand, using solid Fe(III) (hydr)oxides as the iron source led to less productivity of FeS due to their slow and incomplete dissolution and scavenging of sulfide. Furthermore, sufficient free Fe2+, particularly during Fe(III) (hydr)oxide reductions, led to the additional formation of vivianite [Fe3(PO4)2•8(H2O)]. The U(VI) reduction studies revealed that D. vulgaris reduced U(VI) fastest when accumulating sulfide from concomitant sulfate reduction, since direct enzymatic and sulfide-based reductions of U(VI) occurred in parallel. The UO2 produced in presence of ferrous

  7. Removal of chromium from synthetic plating waste by zero-valent iron and sulfate-reducing bacteria.

    PubMed

    Guha, Saumyen; Bhargava, Puja

    2005-01-01

    Experiments were conducted to evaluate the potential of zero-valent iron and sulfate-reducing bacteria (SRB) for reduction and removal of chromium from synthetic electroplating waste. The zero-valent iron shows promising results as a reductant of hexavalent chromium (Cr+6) to trivalent chromium (Cr+3), capable of 100% reduction. The required iron concentration was a function of chromium concentration in the waste stream. Removal of Cr+3 by adsorption or precipitation on iron leads to complete removal of chromium from the waste and was a slower process than the reduction of Cr+6. Presence SRB in a completely mixed batch reactor inhibited the reduction of Cr+6. In a fixed-bed column reactor, SRB enhanced chromium removal and showed promising results for the treatment of wastes with low chromium concentrations. It is proposed that, for waste with high chromium concentration, zero-valent iron is an efficient reductant and can be used for reduction of Cr+6. For low chromium concentrations, a SRB augmented zero-valent iron and sand column is capable of removing chromium completely. PMID:16121509

  8. Corrosion Behavior of Arc-Sprayed Zn-Al Coating in the Presence of Sulfate-Reducing Bacteria in Seawater

    NASA Astrophysics Data System (ADS)

    Hong, Sheng; Wu, Yuping; Gao, Wenwen; Zhang, Jianfeng; Qin, Yujiao

    2015-11-01

    Zn-Al coatings were prepared by high-velocity arc spraying process and were sealed by the silicone resin to improve their corrosion resistance. The corrosion behavior of the unsealed and sealed Zn-Al coatings in the presence of sulfate-reducing bacteria (SRB) in seawater was evaluated, and the related mechanism was discussed. The results showed that the charge transfer resistance value of the sealed coating was almost ten times higher than that of the unsealed coating, and the concentration of element S in the covering layer of the former was half lower than that of the latter. The corrosion resistance of the coating was apparently improved by the sealing treatment. The corrosion rate of the coatings first increased and then decreased during the immersion time of 8 days in the seawater with SRB. The removal of the passive films in the initial period was attributed to penetration of the corrosion medium into the coating and the dissolution of the active zones inside the coating. The adhesion of SRB and accumulation of corrosion products on the coating surface would protect the coating from being further damaged.

  9. Solid and liquid media for isolating and cultivating acidophilic and acid-tolerant sulfate-reducing bacteria.

    PubMed

    Ňancucheo, Ivan; Rowe, Owen F; Hedrich, Sabrina; Johnson, D Barrie

    2016-05-01

    Growth media have been developed to facilitate the enrichment and isolation of acidophilic and acid-tolerant sulfate-reducing bacteria (aSRB) from environmental and industrial samples, and to allow their cultivation in vitro The main features of the 'standard' solid and liquid devised media are as follows: (i) use of glycerol rather than an aliphatic acid as electron donor; (ii) inclusion of stoichiometric concentrations of zinc ions to both buffer pH and to convert potentially harmful hydrogen sulphide produced by the aSRB to insoluble zinc sulphide; (iii) inclusion of Acidocella aromatica (an heterotrophic acidophile that does not metabolize glycerol or yeast extract) in the gel underlayer of double layered (overlay) solid media, to remove acetic acid produced by aSRB that incompletely oxidize glycerol and also aliphatic acids (mostly pyruvic) released by acid hydrolysis of the gelling agent used (agarose). Colonies of aSRB are readily distinguished from those of other anaerobes due to their deposition and accumulation of metal sulphide precipitates. Data presented illustrate the effectiveness of the overlay solid media described for isolating aSRB from acidic anaerobic sediments and low pH sulfidogenic bioreactors. PMID:27036143

  10. Influence of four antimicrobials on methane-producing archaea and sulfate-reducing bacteria in anaerobic granular sludge.

    PubMed

    Du, Jingru; Hu, Yong; Qi, Weikang; Zhang, Yanlong; Jing, Zhaoqian; Norton, Michael; Li, Yu-You

    2015-12-01

    The influence of Cephalexin (CLX), Tetracycline (TC), Erythromycin (ERY) and Sulfathiazole (ST) on methane-producing archaea (MPA) and sulfate-reducing bacteria (SRB) in anaerobic sludge was investigated using acetate or ethanol as substrate. With antimicrobial concentrations below 400mgL(-1), the relative specific methanogenic activity (SMA) was above 50%, so that the antimicrobials exerted slight effects on archaea. However ERY and ST at 400mgL(-1) caused a 74.5% and 57.6% inhibition to specific sulfidogenic activity (SSA) when the sludge granules were disrupted and ethanol used as substrate. After disruption, microbial tolerance to antimicrobials decreased, but the rate at which MPA utilized acetate and ethanol increased from 0.95gCOD·(gVSS⋅d)(-1) to 1.45gCOD·(gVSS⋅d)(-1) and 0.90gCOD·(gVSS⋅d)(-1) to 1.15gCOD·(gVSS⋅d)(-1) respectively. The ethanol utilization rate for SRB also increased after disruption from 0.35gCOD·(gVSS⋅d)(-1) to 0.46gCOD·(gVSS⋅d)(-1). Removal rates for CLX approaching 20.0% and 25.0% were obtained used acetate and ethanol respectively. The disintegration of granules improved the CLX removal rate to 65% and 78%, but ST was not removed during this process. PMID:25228232

  11. Influence of Sulfate-Reducing Bacteria on the Corrosion Behavior of High Strength Steel EQ70 under Cathodic Polarization.

    PubMed

    Guan, Fang; Zhai, Xiaofan; Duan, Jizhou; Zhang, Meixia; Hou, Baorong

    2016-01-01

    Certain species of sulfate-reducing bacteria (SRB) use cathodes as electron donors for metabolism, and this electron transfer process may influence the proper protection potential choice for structures. The interaction between SRB and polarized electrodes had been the focus of numerous investigations. In this paper, the impact of cathodic protection (CP) on Desulfovibrio caledoniens metabolic activity and its influence on highs trength steel EQ70 were studied by bacterial analyses and electrochemical measurements. The results showed that EQ70 under -0.85 VSCE CP had a higher corrosion rate than that without CP, while EQ70 with -1.05 VSCE had a lower corrosion rate. The enhanced SRB metabolic activity at -0.85 VSCE was most probably caused by the direct electron transfer from the electrode polarized at -0.85 VSCE. This direct electron transfer pathway was unavailable in -1.05 VSCE. In addition, the application of cathodic protection led to the transformation of sulfide rusts into carbonates rusts. These observations have been employed to provide updated recommendations for the optimum CP potential for steel structures in the presence of SRB. PMID:27603928

  12. Kinetic Properties of Pyruvate Ferredoxin Oxidoreductase of Intestinal Sulfate-Reducing Bacteria Desulfovibrio piger Vib-7 and Desulfomicrobium sp. Rod-9.

    PubMed

    Kushkevych, Ivan V

    2015-01-01

    Intestinal sulfate-reducing bacteria reduce sulfate ions to hydrogen sulfide causing inflammatory bowel diseases of humans and animals. The bacteria consume lactate as electron donor which is oxidized to acetate via pyruvate in process of the dissimilatory sulfate reduction. Pyruvate-ferredoxin oxidoreductase activity and the kinetic properties of the enzyme from intestinal sulfate-reducing bacteria Desulfovibrio piger and Desulfomicrobium sp. have never been well-characterized and have not been yet studied. In this paper we present for the first time the specific activity of pyruvate-ferredoxin oxidoreductase and the kinetic properties of the enzyme in cell-free extracts of both D. piger Vib-7 and Desulfomicrobium sp. Rod-9 intestinal bacterial strains. Microbiological, biochemical, biophysical and statistical methods were used in this work. The optimal temperature (+35°C) and pH 8.5 for enzyme reaction were determined. The spectral analysis of the puri- fied pyruvate-ferredoxin oxidoreductase from the cell-free extracts was demonstrated. Analysis of the kinetic properties of the studied enzyme was carried out. Initial (instantaneous) reaction velocity (V0), maximum amount of the product of reaction (Pmax), the reaction time (half saturation period) and maximum velocity of the pyruvate-ferredoxin oxidoreductase reaction (V ) were defined. Michaelis constants (Km) of the enzyme reaction were calculated for both intestinal bacterial strains. The studies of the kinetic enzyme properties in the intestinal sulfate-reducing bacteria strains in detail can be prospects for clarifying the etiological role of these bacteria in the development of inflammatory bowel diseases. PMID:26373169

  13. Isolation of sulfate-reducing bacteria from the terrestrial deep subsurface and description of Desulfovibrio cavernae sp. nov.

    PubMed

    Sass, Henrik; Cypionka, Heribert

    2004-09-01

    Deep subsurface sandstones in the area of Berlin (Germany) located 600 to 1060 m below the surface were examined for the presence of viable microorganisms. The in situ temperatures at the sampling sites ranged from 37 to 45 degrees C. Investigations focussed on sulfate-reducing bacteria able to grow on methanol and triethylene glycol, which are added as chemicals to facilitate the long-term underground storage of natural gas. Seven strains were isolated from porewater brines in the porous sandstone. Three of them were obtained with methanol (strains H1M, H3M, and B1M), three strains with triethylene glycol (strains H1T, B1T, and B2T) and one strain with a mixture of lactate, acetate and butyrate (strain H1-13). Due to phenotypic properties six isolates could be identified as members of the genus Desulfovibrio, and strain B2T as a Desulfotomaculum. The salt tolerance and temperature range for growth indicated that the isolates originated from the indigenous deep subsurface sandstones. They grew in mineral media reflecting the in situ ionic composition of the different brines, which contained 1.5 to 190 g NaCl x l(-1) and high calcium and magnesium concentrations. The Desulfovibrio strains grew at temperatures between 20 and 50 degrees C, while the Desulfotomaculum strain was thermophilic and grew between 30 and 65 degrees C. The strains utilized a broad spectrum of electron donors and acceptors. They grew with carbon compounds like lactate, pyruvate, formate, n-alcohols (C1-C5), glycerol, ethylene glycol, malate, succinate, and fumarate. Some strains even utilized glucose as electron donor and carbon source. All strains were able to use sulfate, sulfite and nitrate as electron acceptors. Additionally, three Desulfovibrio strains reduced manganese oxide, the Desulfotomaculum strain reduced manganese oxide, iron oxide, and elemental sulfur. The 16S rRNA analysis revealed that the isolates belong to three different species. The strains H1T, H3M and B1M could be

  14. Anaerobic BTEX degradation in oil sands tailings ponds: Impact of labile organic carbon and sulfate-reducing bacteria.

    PubMed

    Stasik, Sebastian; Wick, Lukas Y; Wendt-Potthoff, Katrin

    2015-11-01

    The extraction of bitumen from oil sands in Alberta (Canada) produces volumes of tailings that are pumped into large anaerobic settling-basins. Beside bitumen, tailings comprise fractions of benzene, toluene, ethylbenzene and xylenes (BTEX) that derive from the application of industrial solvents. Due to their toxicity and volatility, BTEX pose a strong concern for gas- and water-phase environments in the vicinity of the ponds. The examination of two pond profiles showed that concentrations of indigenous BTEX decreased with depth, pointing at BTEX transformation in situ. With depth, the relative contribution of ethylbenzene and xylenes to total BTEX significantly decreased, while benzene increased relatively from 44% to 69%, indicating preferential hydrocarbon degradation. To predict BTEX turnover and residence time, we determined BTEX degradation rates in tailings of different depths in a 180-days microcosm study. In addition, we evaluated the impact of labile organic substrates (e.g. acetate) generally considered to stimulate hydrocarbon degradation and the contribution of sulfate-reducing bacteria (SRB) to BTEX turnover. In all depths, BTEX concentrations significantly decreased due to microbial activity, with degradation rates ranging between 4 and 9 μg kg(-1) d(-1). BTEX biodegradation decreased linearly in correlation with initial concentrations, suggesting a concentration-dependent BTEX transformation. SRB were not significantly involved in BTEX consumption, indicating the importance of methanogenic degradation. BTEX removal decreased to 70-90% in presence of organic substrates presumptively due to an accumulation of acetate that lowered BTEX turnover due to product inhibition. In those assays SRB slightly stimulated BTEX transformation by reducing inhibitory acetate levels. PMID:26066083

  15. Purification and characterization of a surfactin-like molecule produced by Bacillus sp. H2O-1 and its antagonistic effect against sulfate reducing bacteria

    PubMed Central

    2012-01-01

    Background Bacillus sp. H2O-1, isolated from the connate water of a Brazilian reservoir, produces an antimicrobial substance (denoted as AMS H2O-1) that is active against sulfate reducing bacteria, which are the major bacterial group responsible for biogenic souring and biocorrosion in petroleum reservoirs. Thus, the use of AMS H2O-1 for sulfate reducing bacteria control in the petroleum industry is a promising alternative to chemical biocides. However, prior to the large-scale production of AMS H2O-1 for industrial applications, its chemical structure must be elucidated. This study also analyzed the changes in the wetting properties of different surfaces conditioned with AMS H2O-1 and demonstrated the effect of AMS H2O-1 on sulfate reducing bacteria cells. Results A lipopeptide mixture from AMS H2O-1 was partially purified on a silica gel column and identified via mass spectrometry (ESI-MS). It comprises four major components that range in size from 1007 to 1049 Da. The lipid moiety contains linear and branched β-hydroxy fatty acids that range in length from C13 to C16. The peptide moiety contains seven amino acids identified as Glu-Leu-Leu-Val-Asp-Leu-Leu. Transmission electron microscopy revealed cell membrane alteration of sulfate reducing bacteria after AMS H2O-1 treatment at the minimum inhibitory concentration (5 μg/ml). Cytoplasmic electron dense inclusions were observed in treated cells but not in untreated cells. AMS H2O-1 enhanced the osmosis of sulfate reducing bacteria cells and caused the leakage of the intracellular contents. In addition, contact angle measurements indicated that different surfaces conditioned by AMS H2O-1 were less hydrophobic and more electron-donor than untreated surfaces. Conclusion AMS H2O-1 is a mixture of four surfactin-like homologues, and its biocidal activity and surfactant properties suggest that this compound may be a good candidate for sulfate reducing bacteria control. Thus, it is a potential alternative to the

  16. Application of Denaturing High-Performance Liquid Chromatography for Monitoring Sulfate-Reducing Bacteria in Oil Fields

    PubMed Central

    Nyyssönen, Mari; Bomberg, Malin; Laitila, Arja; Simell, Jaakko; Kapanen, Anu; Juvonen, Riikka

    2013-01-01

    Sulfate-reducing bacteria (SRB) participate in microbially induced corrosion (MIC) of equipment and H2S-driven reservoir souring in oil field sites. Successful management of industrial processes requires methods that allow robust monitoring of microbial communities. This study investigated the applicability of denaturing high-performance liquid chromatography (DHPLC) targeting the dissimilatory sulfite reductase ß-subunit (dsrB) gene for monitoring SRB communities in oil field samples from the North Sea, the United States, and Brazil. Fifteen of the 28 screened samples gave a positive result in real-time PCR assays, containing 9 × 101 to 6 × 105 dsrB gene copies ml−1. DHPLC and denaturing gradient gel electrophoresis (DGGE) community profiles of the PCR-positive samples shared an overall similarity; both methods revealed the same samples to have the lowest and highest diversity. The SRB communities were diverse, and different dsrB compositions were detected at different geographical locations. The identified dsrB gene sequences belonged to several phylogenetic groups, such as Desulfovibrio, Desulfococcus, Desulfomicrobium, Desulfobulbus, Desulfotignum, Desulfonatronovibrio, and Desulfonauticus. DHPLC showed an advantage over DGGE in that the community profiles were very reproducible from run to run, and the resolved gene fragments could be collected using an automated fraction collector and sequenced without a further purification step. DGGE, on the other hand, included casting of gradient gels, and several rounds of rerunning, excising, and reamplification of bands were needed for successful sequencing. In summary, DHPLC proved to be a suitable tool for routine monitoring of the diversity of SRB communities in oil field samples. PMID:23793633

  17. Significant Association between Sulfate-Reducing Bacteria and Uranium-Reducing Microbial Communities as Revealed by a Combined Massively Parallel Sequencing-Indicator Species Approach

    SciTech Connect

    Cardenas, Erick; Leigh, Mary Beth; Marsh, Terence; Tiedje, James M.; Wu, Wei-min; Luo, Jian; Ginder-Vogel, Matthew; Kitanidis, Peter K.; Criddle, Craig; Carley, Jack M; Carroll, Sue L; Gentry, Terry J; Watson, David B; Gu, Baohua; Jardine, Philip M; Zhou, Jizhong

    2010-10-01

    Massively parallel sequencing has provided a more affordable and high-throughput method to study microbial communities, although it has mostly been used in an exploratory fashion. We combined pyrosequencing with a strict indicator species statistical analysis to test if bacteria specifically responded to ethanol injection that successfully promoted dissimilatory uranium(VI) reduction in the subsurface of a uranium contamination plume at the Oak Ridge Field Research Center in Tennessee. Remediation was achieved with a hydraulic flow control consisting of an inner loop, where ethanol was injected, and an outer loop for flow-field protection. This strategy reduced uranium concentrations in groundwater to levels below 0.126 M and created geochemical gradients in electron donors from the inner-loop injection well toward the outer loop and downgradient flow path. Our analysis with 15 sediment samples from the entire test area found significant indicator species that showed a high degree of adaptation to the three different hydrochemical-created conditions. Castellaniella and Rhodanobacter characterized areas with low pH, heavy metals, and low bioactivity, while sulfate-, Fe(III)-, and U(VI)-reducing bacteria (Desulfovibrio, Anaeromyxobacter, and Desulfosporosinus) were indicators of areas where U(VI) reduction occurred. The abundance of these bacteria, as well as the Fe(III) and U(VI) reducer Geobacter, correlated with the hydraulic connectivity to the substrate injection site, suggesting that the selected populations were a direct response to electron donor addition by the groundwater flow path. A false-discovery-rate approach was implemented to discard false-positive results by chance, given the large amount of data compared.

  18. Significant association between sulfate-reducing bacteria and uranium-reducing microbial communities as revealed by a combined massively parallel sequencing-indicator species approach.

    PubMed

    Cardenas, Erick; Wu, Wei-Min; Leigh, Mary Beth; Carley, Jack; Carroll, Sue; Gentry, Terry; Luo, Jian; Watson, David; Gu, Baohua; Ginder-Vogel, Matthew; Kitanidis, Peter K; Jardine, Philip M; Zhou, Jizhong; Criddle, Craig S; Marsh, Terence L; Tiedje, James M

    2010-10-01

    Massively parallel sequencing has provided a more affordable and high-throughput method to study microbial communities, although it has mostly been used in an exploratory fashion. We combined pyrosequencing with a strict indicator species statistical analysis to test if bacteria specifically responded to ethanol injection that successfully promoted dissimilatory uranium(VI) reduction in the subsurface of a uranium contamination plume at the Oak Ridge Field Research Center in Tennessee. Remediation was achieved with a hydraulic flow control consisting of an inner loop, where ethanol was injected, and an outer loop for flow-field protection. This strategy reduced uranium concentrations in groundwater to levels below 0.126 μM and created geochemical gradients in electron donors from the inner-loop injection well toward the outer loop and downgradient flow path. Our analysis with 15 sediment samples from the entire test area found significant indicator species that showed a high degree of adaptation to the three different hydrochemical-created conditions. Castellaniella and Rhodanobacter characterized areas with low pH, heavy metals, and low bioactivity, while sulfate-, Fe(III)-, and U(VI)-reducing bacteria (Desulfovibrio, Anaeromyxobacter, and Desulfosporosinus) were indicators of areas where U(VI) reduction occurred. The abundance of these bacteria, as well as the Fe(III) and U(VI) reducer Geobacter, correlated with the hydraulic connectivity to the substrate injection site, suggesting that the selected populations were a direct response to electron donor addition by the groundwater flow path. A false-discovery-rate approach was implemented to discard false-positive results by chance, given the large amount of data compared. PMID:20729318

  19. A combined massively parallel sequencing indicator species approach revealed significant association between sulfate-reducing bacteria and uranium-reducing microbial communities

    SciTech Connect

    Cardenas, Erick; Wu, Wei-min; Leigh, Mary Beth; Carley, Jack M; Carroll, Sue L; Gentry, Terry; Luo, Jian; Watson, David B; Gu, Baohua; Ginder-Vogel, Matthew A.; Kitanidis, Peter K.; Jardine, Philip; Kelly, Shelly D; Zhou, Jizhong; Criddle, Craig; Marsh, Terence; Tiedje, James

    2010-08-01

    Massively parallel sequencing has provided a more affordable and high throughput method to study microbial communities, although it has been mostly used in an exploratory fashion. We combined pyrosequencing with a strict indicator species statistical analysis to test if bacteria specifically responded to ethanol injection that successfully promoted dissimilatory uranium (VI) reduction in the subsurface of a uranium contamination plume at the Oak Ridge Field Research Center in Tennessee, USA. Remediation was achieved with a hydraulic flow control consisting of an inner loop, where ethanol was injected, and an outer loop for flow field protection. This strategy reduced uranium concentrations in groundwater to levels below 0.126 {micro}M, and created geochemical gradients in electron donors from the inner loop injection well towards the outer loop and down-gradient flow path. Our analysis with 15 sediment samples from the entire test area found significant indicator species that showed a high degree of adaptation to the three different hydrochemical created conditions. Castellaniella, and Rhodanobacter characterized areas with low pH, heavy metals, and low bioactivity; while sulfate-, Fe(III)-, and U(VI)-reducing bacteria (Desulfovibrio, Anaeromyxobacter, and Desulfosporosinus) were indicators of areas where U(VI) reduction occurred. Abundance of these bacteria as well as the Fe(III)- and U(VI)-reducer Geobacter correlated with the hydraulic connectivity to the substrate injection site, suggesting that the selected populations were a direct response to the electron donor addition and by the groundwater flow path. A false discovery rate approach was implemented to discard false positives by chance given the large amount of data compared.

  20. Assessing the Role of Iron Sulfides in the Long Term Sequestration of U by Sulfate Reducing Bacteria

    SciTech Connect

    Rittman, Bruce; Zhou, Chen; Vannela, Raveender

    2013-12-31

    This four-year project’s overarching aim was to identify the role of biogenic and synthetic iron-sulfide minerals in the long-term sequestration of reduced U(IV) formed under sulfate-reducing conditions when subjected to re-oxidizing conditions. As stated in this final report, significant progress was achieved through the collaborative research effort conducted at Arizona State University (ASU) and the University of Michigan (UM).

  1. Diversity of sulfate-reducing bacteria in oxic and anoxic regions of a microbial mat characterized by comparative analysis of dissimilatory sulfite reductase genes

    SciTech Connect

    Minz, D.; Flax, J.L.; Green, S.J.; Muyzer, G.; Cohen, Y.; Wagner, M.; Rittmann, B.E.; Stahl, D.A.

    1999-10-01

    Sequence analysis of genes encoding dissimilatory sulfite reductase (DSR) was used to identify sulfate-reducing bacteria in a hypersaline microbial mat and to evaluate their distribution in relation to levels of oxygen. The most highly diverse DSR sequences, most related to those of the Desulfonema-like organisms within the {delta}-proteobacteria, were recovered from oxic regions of the mat. This observation extends those of previous studies by the authors and others associating Desulfonema-like organisms with oxic habitats.

  2. Effects of legacy nuclear waste on the compositional diversity and distributions of sulfate-reducing bacteria in a terrestrial subsurface aquifer.

    PubMed

    Bagwell, Christopher E; Liu, Xuaduan; Wu, Liyou; Zhou, Jizhong

    2006-03-01

    The impact of legacy nuclear waste on the compositional diversity and distribution of sulfate-reducing bacteria in a heavily contaminated subsurface aquifer was examined. dsrAB clone libraries were constructed and restriction fragment length polymorphism (RFLP) analysis used to evaluate genetic variation between sampling wells. Principal component analysis identified nickel, nitrate, technetium, and organic carbon as the primary variables contributing to well-to-well geochemical variability, although comparative sequence analysis showed the sulfate-reducing bacteria community structure to be consistent throughout contaminated and uncontaminated regions of the aquifer. Only 3% of recovered dsrAB gene sequences showed apparent membership to the Deltaproteobacteria. The remainder of recovered sequences may represent novel, deep-branching lineages that, to our knowledge, do not presently contain any cultivated members; although corresponding phylotypes have recently been reported from several different marine ecosystems. These findings imply resiliency and adaptability of sulfate-reducing bacteria to extremes in environmental conditions, although the possibility for horizontal transfer of dsrAB is also discussed. PMID:16466381

  3. Effects of Spartina alterniflora invasion on the communities of methanogens and sulfate-reducing bacteria in estuarine marsh sediments

    PubMed Central

    Zeleke, Jemaneh; Sheng, Qiang; Wang, Jian-Gong; Huang, Ming-Yao; Xia, Fei; Wu, Ji-Hua; Quan, Zhe-Xue

    2013-01-01

    The effect of plant invasion on the microorganisms of soil sediments is very important for estuary ecology. The community structures of methanogens and sulfate-reducing bacteria (SRB) as a function of Spartina alterniflora invasion in Phragmites australis-vegetated sediments of the Dongtan wetland in the Yangtze River estuary, China, were investigated using 454 pyrosequencing and quantitative real-time PCR (qPCR) of the methyl coenzyme M reductase A (mcrA) and dissimilatory sulfite-reductase (dsrB) genes. Sediment samples were collected from two replicate locations, and each location included three sampling stands each covered by monocultures of P. australis, S. alterniflora and both plants (transition stands), respectively. qPCR analysis revealed higher copy numbers of mcrA genes in sediments from S. alterniflora stands than P. australis stands (5- and 7.5-fold more in the spring and summer, respectively), which is consistent with the higher methane flux rates measured in the S. alterniflora stands (up to 8.01 ± 5.61 mg m−2 h−1). Similar trends were observed for SRB, and they were up to two orders of magnitude higher than the methanogens. Diversity indices indicated a lower diversity of methanogens in the S. alterniflora stands than the P. australis stands. In contrast, insignificant variations were observed in the diversity of SRB with the invasion. Although Methanomicrobiales and Methanococcales, the hydrogenotrophic methanogens, dominated in the salt marsh, Methanomicrobiales displayed a slight increase with the invasion and growth of S. alterniflora, whereas the later responded differently. Methanosarcina, the metabolically diverse methanogens, did not vary with the invasion of, but Methanosaeta, the exclusive acetate utilizers, appeared to increase with S. alterniflora invasion. In SRB, sequences closely related to the families Desulfobacteraceae and Desulfobulbaceae dominated in the salt marsh, although they displayed minimal changes with the S

  4. Properties of Desulfovibrio carbinolicus sp. nov. and Other Sulfate-Reducing Bacteria Isolated from an Anaerobic-Purification Plant

    PubMed Central

    Nanninga, Henk J.; Gottschal, Jan C.

    1987-01-01

    Several sulfate-reducing microorganisms were isolated from an anaerobic-purification plant. Four strains were classified as Desulfovibrio desulfuricans, Desulfovibrio sapovorans, Desulfobulbus propionicus, and Desulfovibrio sp. The D. sapovorans strain contained poly-β-hydroxybutyrate granules and seemed to form extracellular vesicles. A fifth isolate, Desulfovibrio sp. strain EDK82, was a gram-negative, non-spore-forming, nonmotile, curved organism. It was able to oxidize several substrates, including methanol. Sulfate, sulfite, thiosulfate, and sulfur were utilized as electron acceptors. Pyruvate, fumarate, malate, and glycerol could be fermented. Because strain EDK82 could not be ascribed to any of the existing species, a new species, Desulfovibrio carbinolicus, is proposed. The doubling times of the isolates were determined on several substrates. Molecular hydrogen, lactate, propionate, and ethanol yielded the shortest doubling times (3.0 to 6.3 h). Due to the presence of support material in an anaerobic filter system, these species were able to convert sulfate to sulfide very effectively at a hydraulic retention time as short as 0.5 h. Images PMID:16347324

  5. Lipid and carbon isotopic evidence of methane-oxidizing and sulfate-reducing bacteria in association with gas hydrates from the Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Zhang, Chuanlun L.; Li, Yiliang; Wall, Judy D.; Larsen, Lise; Sassen, Roger; Huang, Yongsong; Wang, Yi; Peacock, Aaron; White, David C.; Horita, Juske; Cole, David R.

    2002-03-01

    An integrated lipid biomarker carbon isotope approach reveals new insight to microbial methane oxidation in the Gulf of Mexico gas-hydrate system. Hydrate-bearing and hydrate-free sediments were collected from the Gulf of Mexico slope using a research submersible. Phospholipid fatty acids consist mainly of C16 C18 compounds, which are largely derived from bacteria. The phospholipid fatty acids suggest that total biomass is enhanced 11 30-fold in gas-hydrate bearing sediment compared to hydrate-free sediment. Lipid biomarkers indicative of sulfate-reducing bacteria are strongly depleted in 13C (δ13C = -48‰ to -70‰) in the hydrate-bearing samples, suggesting that they are involved in the oxidation of methane (δ13C = -47‰ for thermogenic methane and -70‰ for biogenic methane). Isotopic properties of other biomarkers suggest that sulfur-oxidizing bacteria (Beggiatoa) may also contribute to the lipid pool in hydrate-bearing samples, which are characterized by less negative δ13C values (to -11.2‰). In the hydrate-free sample, fatty acid biomarkers have δ13C values of -27.6‰ to -39.6‰, indicating that crude oil (average ˜-27‰) or terrestrial organic carbon (average ˜-20‰) are the likely carbon sources. Our results provide the first lipid biomarker stable isotope evidence that sulfate- reducing bacteria play an important role in anaerobic methane oxidation in the Gulf of Mexico gas hydrates. The coupled activities of methane-oxidizing and sulfate-reducing organisms contribute to the development of ecosystems in deep-sea environments and result in sequestration of carbon as buried organic carbon and authigenic carbonates. These have implications for studying climate change based on carbon budgets.

  6. Quantification of Tinto River Sediment Microbial Communities: Importance of Sulfate-Reducing Bacteria and Their Role in Attenuating Acid Mine Drainage

    PubMed Central

    Sánchez-Andrea, Irene; Knittel, Katrin; Amann, Rudolf; Amils, Ricardo

    2012-01-01

    Tinto River (Huelva, Spain) is a natural acidic rock drainage (ARD) environment produced by the bio-oxidation of metallic sulfides from the Iberian Pyritic Belt. This study quantified the abundance of diverse microbial populations inhabiting ARD-related sediments from two physicochemically contrasting sampling sites (SN and JL dams). Depth profiles of total cell numbers differed greatly between the two sites yet were consistent in decreasing sharply at greater depths. Although catalyzed reporter deposition fluorescence in situ hybridization with domain-specific probes showed that Bacteria (>98%) dominated over Archaea (<2%) at both sites, important differences were detected at the class and genus levels, reflecting differences in pH, redox potential, and heavy metal concentrations. At SN, where the pH and redox potential are similar to that of the water column (pH 2.5 and +400 mV), the most abundant organisms were identified as iron-reducing bacteria: Acidithiobacillus spp. and Acidiphilium spp., probably related to the higher iron solubility at low pH. At the JL dam, characterized by a banded sediment with higher pH (4.2 to 6.2), more reducing redox potential (−210 mV to 50 mV), and a lower solubility of iron, members of sulfate-reducing genera Syntrophobacter, Desulfosporosinus, and Desulfurella were dominant. The latter was quantified with a newly designed CARD-FISH probe. In layers where sulfate-reducing bacteria were abundant, pH was higher and redox potential and levels of dissolved metals and iron were lower. These results suggest that the attenuation of ARD characteristics is biologically driven by sulfate reducers and the consequent precipitation of metals and iron as sulfides. PMID:22544246

  7. Inhibiting mild steel corrosion from sulfate-reducing and iron-oxidizing bacteria using gramicidin-S-producing biofilms.

    PubMed

    Zuo, Rongjun; Wood, Thomas K

    2004-11-01

    A gramicidin-S-producing Bacillus brevis 18-3 biofilm was shown to reduce corrosion rates of mild steel by inhibiting both the sulfate-reducing bacterium Desulfosporosinus orientis and the iron-oxidizing bacterium Leptothrix discophora SP-6. When L. discophora SP-6 was introduced along with D. orientis to a non-antimicrobial-producing biofilm control, Paenibacillus polymyxa ATCC 10401, a corrosive synergy was created and mild steel coupons underwent more severe corrosion than when only D. orientis was present, showing a 2.3-fold increase via electrochemical impedance spectroscopy (EIS) and a 1.8-fold difference via mass-loss measurements. However, when a gramicidin-S-producing, protective B. brevis 18-3 biofilm was established on mild steel, the metal coupons were protected against the simultaneous attack of D. orientis and L. discophora SP-6. EIS data showed that the protective B. brevis 18-3 biofilm decreased the corrosion rate about 20-fold compared with the non-gramicidin-producing P. polymyxa ATCC 10401 biofilm control. The mass loss for the protected mild steel coupons was also significantly lower than that for the unprotected ones (4-fold decrease). Scanning electron microscope images corroborated the corrosion inhibition by the gramicidin-S-producing B. brevis biofilm on mild steel by showing that the metal surface remained untarnished, i.e., the polishing grooves were still visible after exposure to the simultaneous attack of the sulfate-reducing bacterium and the iron-oxidizing bacterium. PMID:15278311

  8. Reverse Sample Genome Probing, a New Technique for Identification of Bacteria in Environmental Samples by DNA Hybridization, and Its Application to the Identification of Sulfate-Reducing Bacteria in Oil Field Samples

    PubMed Central

    Voordouw, Gerrit; Voordouw, Johanna K.; Karkhoff-Schweizer, Roxann R.; Fedorak, Phillip M.; Westlake, Donald W. S.

    1991-01-01

    A novel method for the identification of bacteria in environmental samples by DNA hybridization is presented. It is based on the fact that, even within a genus, the genomes of different bacteria may have little overall sequence homology. This allows the use of the labeled genomic DNA of a given bacterium (referred to as a “standard”) to probe for its presence and that of bacteria with highly homologous genomes in total DNA obtained from an environmental sample. Alternatively, total DNA extracted from the sample can be labeled and used to probe filters on which denatured chromosomal DNA from relevant bacterial standards has been spotted. The latter technique is referred to as reverse sample genome probing, since it is the reverse of the usual practice of deriving probes from reference bacteria for analyzing a DNA sample. Reverse sample genome probing allows identification of bacteria in a sample in a single step once a master filter with suitable standards has been developed. Application of reverse sample genome probing to the identification of sulfate-reducing bacteria in 31 samples obtained primarily from oil fields in the province of Alberta has indicated that there are at least 20 genotypically different sulfate-reducing bacteria in these samples. Images PMID:16348574

  9. Mercury methylation in Sphagnum moss mats and its association with sulfate-reducing bacteria in an acidic Adirondack forest lake wetland.

    PubMed

    Yu, Ri-Qing; Adatto, Isaac; Montesdeoca, Mario R; Driscoll, Charles T; Hines, Mark E; Barkay, Tamar

    2010-12-01

    Processes leading to the bioaccumulation of methylmercury (MeHg) in northern wetlands are largely unknown. We have studied various ecological niches within a remote, acidic forested lake ecosystem in the southwestern Adirondacks, NY, to discover that mats comprised of Sphagnum moss were a hot spot for mercury (Hg) and MeHg accumulation (190.5 and 18.6 ng g⁻¹ dw, respectively). Furthermore, significantly higher potential methylation rates were measured in Sphagnum mats as compared with other sites within Sunday Lake's ecosystem. Although MPN estimates showed a low biomass of sulfate-reducing bacteria (SRB), 2.8 × 10⁴ cells mL⁻¹ in mat samples, evidence consisting of (1) a twofold stimulation of potential methylation by the addition of sulfate, (2) a significant decrease in Hg methylation in the presence of the sulfate reduction inhibitor molybdate, and (3) presence of dsrAB-like genes in mat DNA extracts, suggested that SRB were involved in Hg methylation. Sequencing of dsrB genes indicated that novel SRB, incomplete oxidizers including Desulfobulbus spp. and Desulfovibrio spp., and syntrophs dominated the sulfate-reducing guild in the Sphagnum moss mat. Sphagnum, a bryophyte dominating boreal peatlands, and its associated microbial communities appear to play an important role in the production and accumulation of MeHg in high-latitude ecosystems. PMID:20955196

  10. The Sulfate-Rich and Extreme Saline Sediment of the Ephemeral Tirez Lagoon: A Biotope for Acetoclastic Sulfate-Reducing Bacteria and Hydrogenotrophic Methanogenic Archaea

    PubMed Central

    Montoya, Lilia; Lozada-Chávez, Irma; Amils, Ricardo; Rodriguez, Nuria; Marín, Irma

    2011-01-01

    Our goal was to examine the composition of methanogenic archaea (MA) and sulfate-reducing (SRP) and sulfur-oxidizing (SOP) prokaryotes in the extreme athalassohaline and particularly sulfate-rich sediment of Tirez Lagoon (Spain). Thus, adenosine-5′-phosphosulfate (APS) reductase α (aprA) and methyl coenzyme M reductase α (mcrA) gene markers were amplified given that both enzymes are specific for SRP, SOP, and MA, respectively. Anaerobic populations sampled at different depths in flooded and dry seasons from the anoxic sediment were compared qualitatively via denaturing gradient gel electrophoresis (DGGE) fingerprint analysis. Phylogenetic analyses allowed the detection of SRP belonging to Desulfobacteraceae, Desulfohalobiaceae, and Peptococcaceae in ∂-proteobacteria and Firmicutes and SOP belonging to Chromatiales/Thiotrichales clade and Ectothiorhodospiraceae in γ-proteobacteria as well as MA belonging to methylotrophic species in Methanosarcinaceae and one hydrogenotrophic species in Methanomicrobiaceae. We also estimated amino acid composition, GC content, and preferential codon usage for the AprA and McrA sequences from halophiles, nonhalophiles, and Tirez phylotypes. Even though our results cannot be currently conclusive regarding the halotolerant strategies carried out by Tirez phylotypes, we discuss the possibility of a plausible “salt-in” signal in SRP and SOP as well as of a speculative complementary haloadaptation between salt-in and salt-out strategies in MA. PMID:21915180

  11. Microcalorimetric studies of the growth of sulfate-reducing bacteria: comparison of the growth parameters of some Desulfovibrio species.

    PubMed

    Traore, A S; Hatchikian, C E; Le Gall, J; Belaich, J P

    1982-02-01

    We performed a comparative study of the growth energetics of some species of Desulfovibrio by measuring microcalorimetric and molar growth yield values. Lactate and pyruvate were used as energy sources for sulfate reduction. On lactate-sulfate media Desulfovibrio desulfuricans Norway, Desulfovibrio gigas, and Desulfovibrio africanus exhibited molar growth yields of 4.1 +/- 0.6, 3.7 +/- 1.7, and 1.8 +/- 0.1 g/mol, respectively, whereas on pyruvate-sulfate media the molar growth yields were higher (8.5 +/- 0.8, 7.7 +/- 1.6, and 3.5 +/- 0.5 g/mol, respectively). Thus, we found that D. africanus was the least efficient species in converting energy into cell material. The uncoupling of energy in this strain was obvious since its catabolic activities were high compared with those of the two other strains. The enthalpy changes associated with lactate and pyruvate metabolism were -49 +/- 0.7 and -70.2 +/- 6.0 jK/mol, respectively, for D. desulfuricans, -76.6 +/- 1.8 and -91.2 +/- 1.1 kJ/mol, respectively, for D. gigas, and -78.8 +/- 7.2 and -88.0 +/- 6.2 kJ/mol, respectively, for D. africanus. D. gigas and D. africanus produced only acetate, CO2 and hydrogen sulfide as metabolic end products. In addition to these normal end products, D. desulfuricans Norway produced a small amount of butanol. This butanol production was interpreted as reflecting a regulatory system of electron flow during the catabolism of both substrates. Such metabolism was comparable to that reported for D. vulgaris, which lost part of the reducing power of its energy sources through hydrogen evolution. PMID:7056697

  12. Anaerobic degradation of propane and butane by sulfate-reducing bacteria enriched from marine hydrocarbon cold seeps

    PubMed Central

    Jaekel, Ulrike; Musat, Niculina; Adam, Birgit; Kuypers, Marcel; Grundmann, Olav; Musat, Florin

    2013-01-01

    The short-chain, non-methane hydrocarbons propane and butane can contribute significantly to the carbon and sulfur cycles in marine environments affected by oil or natural gas seepage. In the present study, we enriched and identified novel propane and butane-degrading sulfate reducers from marine oil and gas cold seeps in the Gulf of Mexico and Hydrate Ridge. The enrichment cultures obtained were able to degrade simultaneously propane and butane, but not other gaseous alkanes. They were cold-adapted, showing highest sulfate-reduction rates between 16 and 20 °C. Analysis of 16S rRNA gene libraries, followed by whole-cell hybridizations with sequence-specific oligonucleotide probes showed that each enrichment culture was dominated by a unique phylotype affiliated with the Desulfosarcina-Desulfococcus cluster within the Deltaproteobacteria. These phylotypes formed a distinct phylogenetic cluster of propane and butane degraders, including sequences from environments associated with hydrocarbon seeps. Incubations with 13C-labeled substrates, hybridizations with sequence-specific probes and nanoSIMS analyses showed that cells of the dominant phylotypes were the first to become enriched in 13C, demonstrating that they were directly involved in hydrocarbon degradation. Furthermore, using the nanoSIMS data, carbon assimilation rates were calculated for the dominant cells in each enrichment culture. PMID:23254512

  13. Bioaccumulation of gold by sulfate-reducing bacteria cultured in the presence of gold(I)-thiosulfate complex

    NASA Astrophysics Data System (ADS)

    Lengke, Maggy; Southam, Gordon

    2006-07-01

    A sulfate-reducing bacterial (SRB) enrichment, from the Driefontein Consolidated Gold Mine, Witwatersrand Basin, Republic of South Africa, was able to destabilize gold(I)-thiosulfate complex (Au(SO)23-) and precipitate elemental gold. The precipitation of gold was observed in the presence of active (live) SRB due to the formation and release of hydrogen sulfide as an end-product of metabolism, and occurred by three possible mechanisms involving iron sulfide, localized reducing conditions, and metabolism. The presence of biogenic iron sulfide caused significant removal of gold from solutions by adsorption and reduction processes on the iron sulfide surfaces. The presence of gold nanoparticles within and immediately surrounding the bacterial cell envelope highlights the presence of localized reducing conditions produced by the bacterial electron transport chain via energy generating reactions within the cell. Specifically, the decrease in redox conditions caused by the release of hydrogen sulfide from the bacterial cells destabilized the Au(SO)23- solutions. The presence of gold as nanoparticles (<10 nm) inside a sub-population of SRB suggests that the reduction of gold was a part of metabolic process. In late stationary phase or death phase, gold nanoparticles that were initially precipitated inside the bacterial cells, were released from the cells and deposited in the bulk solution as addition of gold nanoparticles that already precipitated in the solution. Ultimately, the formation of micrometer-scale sub-octahedral and octahedral gold and spherical aggregates containing octahedral gold was observed.

  14. Abundance and diversity of sulfate-reducing bacteria in the sediment of the Zhou Cun drinking water reservoir in Eastern China.

    PubMed

    Yang, X; Huang, T L; Guo, L; Xia, C; Zhang, H H; Zhou, S L

    2015-01-01

    Sulfate-reducing bacteria (SRB) play an important role in the sediments of bay areas, estuaries, and lakes. However, information regarding the genetic diversity of SRB in the sediments of drinking water reservoirs is scarce. In this study, we collected sediment samples from different sites in the Zhou Cun drinking water reservoir between April and June 2012. To explore the genetic diversity of SRB, we used the most-probable-number (MPN) method, polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE), and a cloning approach. The average content of acid-volatile sulfide at the deepest sampling site was 205.87 μg/g sediment. This result is often associated with a large abundance of SRB in the associated sediment. The highest MPN estimate (1.15 x 10(5) cells/g sediment) was detected in May at the deepest sampling site. The PCR-DGGE fingerprints of SRB based on the dissimilatory sulfite reductase beta subunit (dsrB) gene varied according to the different sampling sites and dates. The highest abundance of SRB in the sediments was predominantly found at the deepest sampling sites, as expected from the acid-volatile sulfide content. The dominant species were Desulfobulbus sp, Desulfobacterium sp, and uncultured sulfate-reducing bacteria. Redundancy analysis revealed that organic matter and the concentrations of nitrogen and phosphorus in the sediments were significantly correlated with the diversity of SRB communities present. The results of this study provide a better understanding of the sulfate-reducing microbial species in the sediments of the Zhou Cun drinking water reservoir. PMID:26125782

  15. Acute toxicity of heavy metals to acetate-utilizing mixed cultures of sulfate-reducing bacteria: EC100 and EC50.

    PubMed

    Utgikar, V P; Chen, B Y; Chaudhary, N; Tabak, H H; Haines, J R; Govind, R

    2001-12-01

    Acid mine drainage from abandoned mines and acid mine pit lakes is an important environmental concern and usually contains appreciable concentrations of heavy metals. Because sulfate-reducing bacteria (SRB) are involved in the treatment of acid mine drainage, knowledge of acute metal toxicity levels for SRB is essential for the proper functioning of the treatment system for acid mine drainage. Quantification of heavy metal toxicity to mixed cultures of SRB is complicated by the confounding effects of metal hydroxide and sulfide precipitation, biosorption, and complexation with the constituents of the reaction matrix. The objective of this paper was to demonstrate that measurements of dissolved metal concentrations could be used to determine the toxicity parameters for mixed cultures of sulfate-reducing bacteria. The effective concentration, 100% (EC100), the lowest initial dissolved metal concentrations at which no sulfate reduction is observed, and the effective concentration, 50% (EC50), the initial dissolved metal concentrations resulting in a 50% decrease in sulfate reduction, for copper and zinc were determined in the present study by means of nondestructive, rapid physical and chemical analytical techniques. The reaction medium used in the experiments was designed specifically (in terms of pH and chemical composition) to provide the nutrients necessary for the sulfidogenic activity of the SRB and to preclude chemical precipitation of the metals under investigation. The toxicity-mitigating effects of biosorption of dissolved metals were also quantified. Anaerobic Hungate tubes were set up (at least in triplicate) and monitored for sulfate-reduction activity. The onset of SRB activity was detected by the blackening of the reaction mixture because of formation of insoluble ferrous sulfide. The EC100 values were found to be 12 mg/L for copper and 20 mg/L for zinc. The dissolved metal concentration measurements were effective as the indicators of the effect of the

  16. Production of electrically-conductive nanoscale filaments by sulfate-reducing bacteria in the microbial fuel cell.

    PubMed

    Eaktasang, Numfon; Kang, Christina S; Lim, Heejun; Kwean, Oh Sung; Cho, Suyeon; Kim, Yohan; Kim, Han S

    2016-06-01

    This study reports that the obligate anaerobic microorganism, Desulfovibrio desulfuricans, a predominant sulfate-reducing bacterium (SRB) in soils and sediments, can produce nanoscale bacterial appendages for extracellular electron transfer. These nanofilaments were electrically-conductive (5.81S·m(-1)) and allowed SRBs to directly colonize the surface of insoluble or solid electron acceptors. Thus, the direct extracellular electron transfer to the insoluble electrode in the microbial fuel cell (MFC) was possible without inorganic electron-shuttling mediators. The production of nanofilaments was stimulated when only insoluble electron acceptors were available for cellular respiration. These results suggest that when availability of a soluble electron acceptor for SRBs (SO4(2-)) is limited, D. desulfuricans initiates the production of conductive nanofilaments as an alternative strategy to transfer electrons to insoluble electron acceptors. The findings of this study contribute to understanding of the role of SRBs in the biotransformation of various substances in soils and sediments and in the MFC. PMID:26818576

  17. The Membrane QmoABC Complex Interacts Directly with the Dissimilatory Adenosine 5′-Phosphosulfate Reductase in Sulfate Reducing Bacteria

    PubMed Central

    Ramos, Ana Raquel; Keller, Kimberly L.; Wall, Judy D.; Pereira, Inês A. Cardoso

    2012-01-01

    The adenosine 5′-phosphosulfate reductase (AprAB) is the enzyme responsible for the reduction of adenosine 5′-phosphosulfate (APS) to sulfite in the biological process of dissimilatory sulfate reduction, which is carried out by a ubiquitous group of sulfate reducing prokaryotes. The electron donor for AprAB has not been clearly identified, but was proposed to be the QmoABC membrane complex, since an aprBA–qmoABC gene cluster is found in many sulfate reducing and sulfur-oxidizing bacteria. The QmoABC complex is essential for sulfate reduction, but electron transfer between QmoABC and AprAB has not been reported. In this work we provide the first direct evidence that QmoABC and AprAB interact in Desulfovibrio spp., using co-immunoprecipitation, cross-linking Far-Western blot, tag-affinity purification, and surface plasmon resonance studies. This showed that the QmoABC–AprAB complex has a strong steady-state affinity (KD = 90 ± 3 nM), but has a transient character due to a fast dissociation rate. Far-Western blot identified QmoA as the Qmo subunit most involved in the interaction. Nevertheless, electron transfer from menaquinol analogs to APS through anaerobically purified QmoABC and AprAB could not be detected. We propose that this reaction requires the involvement of a third partner to allow electron flow driven by a reverse electron bifurcation process, i.e., electron confurcation. This process is deemed essential to allow coupling of APS reduction to chemiosmotic energy conservation. PMID:22536198

  18. Nested PCR and New Primers for Analysis of Sulfate-Reducing Bacteria in Low-Cell-Biomass Environments▿ †

    PubMed Central

    Giloteaux, Ludovic; Goñi-Urriza, Marisol; Duran, Robert

    2010-01-01

    New primers were designed for the amplification of dsrAB genes by nested PCR to investigate the diversity of sulfate-reducing prokaryotes (SRP) in environments with low bacterial cell density. The success of the nested PCR for the determination of SRP diversity was estimated by terminal-restriction fragment length polymorphism analysis in the Reigous, a small creek at an inactive mine (Carnoulès, France), which constitutes an extreme acidic arsenic-rich environment. Nested PCR limits were evaluated in dsrAB-rich sediments, and this technique was compared to direct PCR using either known primers (DSR1F/DSR4R) or new primers (dsr619AF/dsr1905BR). The comparison of clone libraries revealed that, even if the levels of diversity observed were not identical, nested PCR did not reduce the diversity compared to that of direct DSR1F/DSR4R PCR. Clone sequences were affiliated mainly with the Desulfobacteraceae and Desulfohalobiaceae families. Many sequences (∼30%) were related to a deeply branching lineage unaffiliated with any cultured SRP. Although this dsrAB cluster was found in all libraries, the new primers better amplified this lineage, providing more information on this unknown bacterial group. Thanks to these new primers in nested PCR, the SRP community from Carnoulès could be characterized. Specific SRP populations were obtained according to environmental characteristics. Desulfomicrobiaceae-related sequences were recovered in samples with low pH, low levels of dissolved oxygen, and high As content, while sequences belonging to the deeply branching group were found in a less extreme sample. Furthermore, for the first time, dsrAB sequences related to the latter group were recovered from freshwater. PMID:20228118

  19. Identity and abundance of active sulfate-reducing bacteria in deep tidal flat sediments determined by directed cultivation and CARD-FISH analysis.

    PubMed

    Gittel, Antje; Mussmann, Marc; Sass, Henrik; Cypionka, Heribert; Könneke, Martin

    2008-10-01

    The identity and abundance of potentially active sulfate-reducing bacteria (SRB) in several metre deep sediments of a tidal sand flat in the German Wadden Sea were assessed by directed cultivation and cultivation-independent CARD-FISH analysis (catalysed reporter deposition fluorescence in situ hybridization). Presumably abundant SRB from different sediment layers between 0.5 and 4 m depth were selectively enriched in up to million-fold diluted cultures supplemented with lactate, acetate or hydrogen. Partial 16S rRNA gene sequences obtained from highest dilution steps showing sulfide formation indicated growth of deltaproteobacterial SRB belonging to the Desulfobulbaceae and the Desulfobacteraceae as well as of members of the Firmicutes. Subsequent isolation resulted in 10 novel phylotypes of both litho- and organotrophic sulfate-reducing Deltaproteobacteria. Molecular pre-screening identified six isolates as members of the Desulfobulbaceae, sharing highest identities with either candidatus 'Desulfobacterium corrodens' (95-97%) or Desulfobacterium catecholicum (98%), and four isolates as members of Desulfobacteraceae, being related to either Desulfobacter psychrotolerans (98%) or Desulfobacula phenolica (95-97%). Relatives of D. phenolica were exlusively isolated from 50 and 100 cm deep sediments with 10 and 2 mM of pore water sulfate respectively. In contrast, relatives of D. corrodens, D. psychrotolerans and D. catecholicum were also obtained from layers deeper than 100 cm and with less than 2 mM sulfate. The high in situ abundance of members of both families in sediment layers beneath 50 cm could be confirmed via CARD-FISH analysis performed with a set of six SRB-specific oligonucleotide probes. Moreover, SRB represented a numerically significant fraction of the microbial community throughout the sediment (up to 7%) and reached even higher cell numbers in deep, sulfate-poor layers than in the sulfate-rich surface sediment. This relatively large community size of

  20. Antagonistic activity of Bacillus sp. obtained from an Algerian oilfield and chemical biocide THPS against sulfate-reducing bacteria consortium inducing corrosion in the oil industry.

    PubMed

    Gana, Mohamed Lamine; Kebbouche-Gana, Salima; Touzi, Abdelkader; Zorgani, Mohamed Amine; Pauss, André; Lounici, Hakim; Mameri, Nabil

    2011-03-01

    The present study enlightens the role of the antagonistic potential of nonpathogenic strain B21 against sulfate-reducing bacteria (SRB) consortium. The inhibitor effects of strain B21 were compared with those of the chemical biocide tetrakishydroxymethylphosphonium sulfate (THPS), generally used in the petroleum industry. The biological inhibitor exhibited much better and effective performance. Growth of SRB in coculture with bacteria strain B21 antagonist exhibited decline in SRB growth, reduction in production of sulfides, with consumption of sulfate. The observed effect seems more important in comparison with the effect caused by the tested biocide (THPS). Strain B21, a dominant facultative aerobic species, has salt growth requirement always above 5% (w/v) salts with optimal concentration of 10-15%. Phylogenetic analysis based on partial 16S rRNA gene sequences showed that strain B21 is a member of the genus Bacillus, being most closely related to Bacillus qingdaonensis DQ115802 (94.0% sequence similarity), Bacillus aidingensis DQ504377 (94.0%), and Bacillus salarius AY667494 (92.2%). Comparative analysis of partial 16S rRNA gene sequence data plus physiological, biochemical, and phenotypic features of the novel isolate and related species of Bacillus indicated that strain B21 may represent a novel species within the genus Bacillus, named Bacillus sp. (EMBL, FR671419). The results of this study indicate the application potential of Bacillus strain B21 as a biocontrol agent to fight corrosion in the oil industry. PMID:20949304

  1. Nitrate-based niche differentiation by distinct sulfate-reducing bacteria involved in the anaerobic oxidation of methane

    PubMed Central

    Green-Saxena, A; Dekas, A E; Dalleska, N F; Orphan, V J

    2014-01-01

    Diverse associations between methanotrophic archaea (ANME) and sulfate-reducing bacterial groups (SRB) often co-occur in marine methane seeps; however, the ecophysiology of these different symbiotic associations has not been examined. Here, we applied a combination of molecular, geochemical and Fluorescence in situ hybridization (FISH) coupled to nanoscale secondary ion mass spectrometry (FISH-NanoSIMS) analyses of in situ seep sediments and methane-amended sediment incubations from diverse locations (Eel River Basin, Hydrate Ridge and Costa Rican Margin seeps) to investigate the distribution and physiology of a newly identified subgroup of the Desulfobulbaceae (seepDBB) found in consortia with ANME-2c archaea, and compared these with the more commonly observed associations between the same ANME partner and the Desulfobacteraceae (DSS). FISH analyses revealed aggregates of seepDBB cells in association with ANME-2 from both environmental samples and laboratory incubations that are distinct in their structure relative to co-occurring ANME/DSS consortia. ANME/seepDBB aggregates were most abundant in shallow sediment depths below sulfide-oxidizing microbial mats. Depth profiles of ANME/seepDBB aggregate abundance revealed a positive correlation with elevated porewater nitrate relative to ANME/DSS aggregates in all seep sites examined. This relationship with nitrate was supported by sediment microcosm experiments, in which the abundance of ANME/seepDBB was greater in nitrate-amended incubations relative to the unamended control. FISH-NanoSIMS additionally revealed significantly higher 15N-nitrate incorporation levels in individual aggregates of ANME/seepDBB relative to ANME/DSS aggregates from the same incubation. These combined results suggest that nitrate is a geochemical effector of ANME/seepDBB aggregate distribution, and provides a unique niche for these consortia through their utilization of a greater range of nitrogen substrates than the ANME/DSS. PMID:24008326

  2. Inhibiting mild steel corrosion from sulfate-reducing bacteria using antimicrobial-producing biofilms in Three-Mile-Island process water.

    PubMed

    Zuo, R; Ornek, D; Syrett, B C; Green, R M; Hsu, C-H; Mansfeld, F B; Wood, T K

    2004-04-01

    Biofilms were used to produce gramicidin S (a cyclic decapeptide) to inhibit corrosion-causing, sulfate-reducing bacteria (SRB). In laboratory studies these biofilms protected mild steel 1010 continuously from corrosion in the aggressive, cooling service water of the AmerGen Three-Mile-Island (TMI) nuclear plant, which was augmented with reference SRB. The growth of both reference SRB (Gram-positive Desulfosporosinus orientis and Gram-negative Desulfovibrio vulgaris) was shown to be inhibited by supernatants of the gramicidin-S-producing bacteria as well as by purified gramicidin S. Electrochemical impedance spectroscopy and mass loss measurements showed that the protective biofilms decreased the corrosion rate of mild steel by 2- to 10-fold when challenged with the natural SRB of the TMI process water supplemented with D. orientis or D. vulgaris. The relative corrosion inhibition efficiency was 50-90% in continuous reactors, compared to a biofilm control which did not produce the antimicrobial gramicidin S. Scanning electron microscope and reactor images also revealed that SRB attack was thwarted by protective biofilms that secrete gramicidin S. A consortium of beneficial bacteria (GGPST consortium, producing gramicidin S and other antimicrobials) also protected the mild steel. PMID:12898064

  3. Unexpected Population Distribution in a Microbial Mat Community: Sulfate-Reducing Bacteria Localized to the Highly Oxic Chemocline in Contrast to a Eukaryotic Preference for Anoxia

    PubMed Central

    Minz, Dror; Fishbain, Susan; Green, Stefan J.; Muyzer, Gerard; Cohen, Yehuda; Rittmann, Bruce E.; Stahl, David A.

    1999-01-01

    The distribution and abundance of sulfate-reducing bacteria (SRB) and eukaryotes within the upper 4 mm of a hypersaline cyanobacterial mat community were characterized at high resolution with group-specific hybridization probes to quantify 16S rRNA extracted from 100-μm depth intervals. This revealed a preferential localization of SRB within the region defined by the oxygen chemocline. Among the different groups of SRB quantified, including members of the provisional families “Desulfovibrionaceae” and “Desulfobacteriaceae,” Desulfonema-like populations dominated and accounted for up to 30% of total rRNA extracted from certain depth intervals of the chemocline. These data suggest that recognized genera of SRB are not necessarily restricted by high levels of oxygen in this mat community and the possibility of significant sulfur cycling within the chemocline. In marked contrast, eukaryotic populations in this community demonstrated a preference for regions of anoxia. PMID:10508103

  4. Inhibition of hydrogen sulfide, methane, and total gas production and sulfate-reducing bacteria in in vitro swine manure by tannins, with focus on condensed quebracho tannins.

    PubMed

    Whitehead, Terence R; Spence, Cheryl; Cotta, Michael A

    2013-09-01

    Management practices from large-scale swine production facilities have resulted in the increased collection and storage of manure for off-season fertilization use. Odor and emissions produced during storage have increased the tension among rural neighbors and among urban and rural residents. Production of these compounds from stored manure is the result of microbial activity of the anaerobic bacteria populations during storage. In the current study, the inhibitory effects of condensed quebracho tannins on in vitro swine manure for reduction of microbial activity and reduced production of gaseous emissions, including the toxic odorant hydrogen sulfide produced by sulfate-reducing bacteria (SRB), was examined. Swine manure was collected from a local swine facility, diluted in anaerobic buffer, and mixed with 1 % w/v fresh feces. This slurry was combined with quebracho tannins, and total gas and hydrogen sulfide production was monitored over time. Aliquots were removed periodically for isolation of DNA to measure the SRB populations using quantitative PCR. Addition of tannins reduced overall gas, hydrogen sulfide, and methane production by greater than 90 % after 7 days of treatment and continued to at least 28 days. SRB population was also significantly decreased by tannin addition. qRT-PCR of 16S rDNA bacteria genes showed that the total bacterial population was also decreased in these incubations. These results indicate that the tannins elicited a collective effect on the bacterial population and also suggest a reduction in the population of methanogenic microorganisms as demonstrated by reduced methane production in these experiments. Such a generalized effect could be extrapolated to a reduction in other odor-associated emissions during manure storage. PMID:23149758

  5. Simultaneous inhibition of sulfate-reducing bacteria, removal of H2S and production of rhamnolipid by recombinant Pseudomonas stutzeri Rhl: Applications for microbial enhanced oil recovery.

    PubMed

    Zhao, Feng; Zhou, Ji-Dong; Ma, Fang; Shi, Rong-Jiu; Han, Si-Qin; Zhang, Jie; Zhang, Ying

    2016-05-01

    Sulfate-reducing bacteria (SRB) are widely existed in oil production system, and its H2S product inhibits rhamnolipid producing bacteria. In-situ production of rhamnolipid is promising for microbial enhanced oil recovery. Inhibition of SRB, removal of H2S and production of rhamnolipid by recombinant Pseudomonas stutzeri Rhl were investigated. Strain Rhl can simultaneously remove S(2-) (>92%) and produce rhamnolipid (>136mg/l) under S(2-) stress below 33.3mg/l. Rhl reduced the SRB numbers from 10(9) to 10(5)cells/ml, and the production of H2S was delayed and decreased to below 2mg/l. Rhl also produced rhamnolipid and removed S(2-) under laboratory simulated oil reservoir conditions. High-throughput sequencing data demonstrated that addition of strain Rhl significantly changed the original microbial communities of oilfield production water and decreased the species and abundance of SRB. Bioaugmentation of strain Rhl in oilfield is promising for simultaneous control of SRB, removal of S(2-) and enhance oil recovery. PMID:26868152

  6. A green triple biocide cocktail consisting of a biocide, EDDS and methanol for the mitigation of planktonic and sessile sulfate-reducing bacteria.

    PubMed

    Wen, J; Xu, D; Gu, T; Raad, I

    2012-02-01

    Sulfate-reducing bacteria (SRB) cause souring and their biofilms are often the culprit in Microbiologically Influenced Corrosion (MIC). The two most common green biocides for SRB treatment are tetrakis-hydroxymethylphosphonium sulfate (THPS) and glutaraldehyde. It is unlikely that there will be another equally effective green biocide in the market any time soon. This means more effective biocide treatment probably will rely on biocide cocktails. In this work a triple biocide cocktail consisting of glutaraldehyde or THPS, ethylenediaminedisuccinate (EDDS) and methanol was used to treat planktonic SRB and to remove established SRB biofilms. Desulfovibrio vulgaris (ATCC 7757), a corrosive SRB was used as an example in the tests. Laboratory results indicated that with the addition of 10-15% (v/v) methanol to the glutaraldehyde and EDDS double combination, mitigation of planktonic SRB growth in ATCC 1249 medium and a diluted medium turned from inhibition to a kill effect while the chelator dosage was cut from 2,000 to 1,000 ppm. Biofilm removal was achieved when 50 ppm glutaraldehyde combined with 15% methanol and 1,000 ppm EDDS was used. THPS showed similar effects when it was used to replace glutaraldehyde in the triple biocide cocktail to treat planktonic SRB. PMID:22806837

  7. Quantifying Heavy Metals Sequestration by Sulfate-Reducing Bacteria in an Acid Mine Drainage-Contaminated Natural Wetland

    PubMed Central

    Moreau, John W.; Fournelle, John H.; Banfield, Jillian F.

    2013-01-01

    Bioremediation strategies that depend on bacterial sulfate reduction for heavy metals remediation harness the reactivity of these metals with biogenic aqueous sulfide. Quantitative knowledge of the degree to which specific toxic metals are partitioned into various sulfide, oxide, or other phases is important for predicting the long-term mobility of these metals under environmental conditions. Here we report the quantitative partitioning into sedimentary biogenic sulfides of a suite of metals and metalloids associated with acid mine drainage contamination of a natural estuarine wetland for over a century. PMID:23487496

  8. Effects of Long-Term Acid-Mine Drainage Contamination on Diversity and Activity of Sulfate-Reducing Bacteria in a Natural Salt Marsh.

    NASA Astrophysics Data System (ADS)

    Moreau, J. W.; Banfield, J. F.

    2003-12-01

    Constructed wetlands have been studied as sites or analogs for in situ bioremediation of metal contaminants from acid mine drainage (AMD) or industrial sources (e.g. Webb et al. 1998). Wetlands bioremediation necessarily invokes the ubiquity and robustness of sulfate-reducing bacteria (SRB) to sequester dissolved metals into various poorly soluble metal-sulfides (e.g. PbS, CdS). However, few studies of natural wetlands under long-term ecological forcing by AMD or other contaminant sources are available for context. We are investigating the microbial diversity, mineralogy and geochemistry of a highly contaminated salt marsh along the East Central San Francisco Bay. For nearly a half-century, areas within this marsh have received acidic and/or metal-rich groundwaters from near-surface pyrite tailings (transported there from Iron Mountain Mine, near Redding, CA) and local industrial sources (e.g. paint and explosives manufacturers). Sediment cores (30-40 cm long) were taken from six contaminated sites in the marsh with pH range of ˜2 to ˜8. Previous analyses (URS Corp. 2001) reported As, Cd, Cu, Se, Zn, and Pb present in sediments at extremely high concentrations (100s of ppm), yet our ICP-AES analyses of pore waters showed only As present at concentrations of 10-50 ppb. We infer, from high-resolution transmission electron microscope (HRTEM) studies of biogenic (SRB biofilm) ZnS (Moreau et al. 2003, in review) and marsh sediments, that contaminant metals have been sequestered into aggregates of nanocrystalline metal-sulfides. Continuous-flow isotope ratio mass spectrometer (CF-IRMS) analyses of pore-water sulfate and sedimentary sulfides allow resolution of contributions to dissolved sulfate and sulfide from tailings oxidation and dissimilatory sulfate reduction. Sulfate analyses from subsections of three cores (pH 2-3, 6-7, 7-8, respectively) all yield δ 34S values consistent with bacterial sulfate reduction. We note that all three cores also contain very fine

  9. Depth-related coupling relation between methane-oxidizing bacteria (MOBs) and sulfate-reducing bacteria (SRBs) in a marine sediment core from the Dongsha region, the South China Sea.

    PubMed

    Xu, Xiao-Ming; Fu, Shao-Ying; Zhu, Qing; Xiao, Xi; Yuan, Jian-Ping; Peng, Juan; Wu, Chou-Fei; Wang, Jiang-Hai

    2014-12-01

    The vertical distributions of methane-oxidizing bacteria (MOBs) and sulfate-reducing bacteria (SRBs) in the marine sediment core of DH-CL14 from the Dongsha region, the South China Sea, were investigated. To enumerate MOBs and SRBs, their specific genes of pmoA and apsA were quantified by a culture-independent molecular biological technique, real-time polymerase chain reaction (RT-PCR). The result shows that the pmoA gene copies per gram of sediments reached the maximum of 1,118,679 at the depth of 140-160 cm. Overall considering the detection precision, sample amount, measurement cost, and sensitivity to the seepage of methane from the oil/gas reservoirs or gas hydrates, we suggest that the depth of 140-160 cm may be the optimal sampling position for the marine microbial exploration of oils, gases, and gas hydrates in the Dongsha region. The data of the pmoA and apsA gene copies exhibit an evident coupling relation between MOBs and SRBs as illustrated in their vertical distributions in this sediment core, which may well be interpreted by a high sulfate concentration inhibiting methane production and further leading to the reduction of MOBs. In comparison with the numbers of the pmoA and apsA copies at the same sediment depth, we find out that there were two methane-oxidizing mechanisms of aerobic and anaerobic oxidation in this sediment core, i.e., the aerobic oxidation with free oxygen dominantly occurred above the depth of 210-230 cm, while the anaerobic oxidation with the other electron acceptors such as sulfates and manganese-iron oxides happened below the depth of 210-230 cm. PMID:25064353

  10. Mono- and Dialkyl Glycerol Ether Lipids in Anaerobic Bacteria: Biosynthetic Insights from the Mesophilic Sulfate Reducer Desulfatibacillum alkenivorans PF2803T

    PubMed Central

    Mollex, Damien; Vinçon-Laugier, Arnauld; Hakil, Florence; Pacton, Muriel; Cravo-Laureau, Cristiana

    2015-01-01

    Bacterial glycerol ether lipids (alkylglycerols) have received increasing attention during the last decades, notably due to their potential role in cell resistance or adaptation to adverse environmental conditions. Major uncertainties remain, however, regarding the origin, biosynthesis, and modes of formation of these uncommon bacterial lipids. We report here the preponderance of monoalkyl- and dialkylglycerols (1-O-alkyl-, 2-O-alkyl-, and 1,2-O-dialkylglycerols) among the hydrolyzed lipids of the marine mesophilic sulfate-reducing proteobacterium Desulfatibacillum alkenivorans PF2803T grown on n-alkenes (pentadec-1-ene or hexadec-1-ene) as the sole carbon and energy source. Alkylglycerols account for one-third to two-thirds of the total cellular lipids (alkylglycerols plus acylglycerols), depending on the growth substrate, with dialkylglycerols contributing to one-fifth to two-fifths of the total ether lipids. The carbon chain distribution of the lipids of D. alkenivorans also depends on that of the substrate, but the chain length and methyl-branching patterns of fatty acids and monoalkyl- and dialkylglycerols are systematically congruent, supporting the idea of a biosynthetic link between the three classes of compounds. Vinyl ethers (1-alken-1′-yl-glycerols, known as plasmalogens) are not detected among the lipids of strain PF2803T. Cultures grown on different (per)deuterated n-alkene, n-alkanol, and n-fatty acid substrates further demonstrate that saturated alkylglycerols are not formed via the reduction of hypothetic alken-1′-yl intermediates. Our results support an unprecedented biosynthetic pathway to monoalkyl/monoacyl- and dialkylglycerols in anaerobic bacteria and suggest that n-alkyl compounds present in the environment can serve as the substrates for supplying the building blocks of ether phospholipids of heterotrophic bacteria. PMID:25724965

  11. Mono- and dialkyl glycerol ether lipids in anaerobic bacteria: biosynthetic insights from the mesophilic sulfate reducer Desulfatibacillum alkenivorans PF2803T.

    PubMed

    Grossi, Vincent; Mollex, Damien; Vinçon-Laugier, Arnauld; Hakil, Florence; Pacton, Muriel; Cravo-Laureau, Cristiana

    2015-05-01

    Bacterial glycerol ether lipids (alkylglycerols) have received increasing attention during the last decades, notably due to their potential role in cell resistance or adaptation to adverse environmental conditions. Major uncertainties remain, however, regarding the origin, biosynthesis, and modes of formation of these uncommon bacterial lipids. We report here the preponderance of monoalkyl- and dialkylglycerols (1-O-alkyl-, 2-O-alkyl-, and 1,2-O-dialkylglycerols) among the hydrolyzed lipids of the marine mesophilic sulfate-reducing proteobacterium Desulfatibacillum alkenivorans PF2803T grown on n-alkenes (pentadec-1-ene or hexadec-1-ene) as the sole carbon and energy source. Alkylglycerols account for one-third to two-thirds of the total cellular lipids (alkylglycerols plus acylglycerols), depending on the growth substrate, with dialkylglycerols contributing to one-fifth to two-fifths of the total ether lipids. The carbon chain distribution of the lipids of D. alkenivorans also depends on that of the substrate, but the chain length and methyl-branching patterns of fatty acids and monoalkyl- and dialkylglycerols are systematically congruent, supporting the idea of a biosynthetic link between the three classes of compounds. Vinyl ethers (1-alken-1'-yl-glycerols, known as plasmalogens) are not detected among the lipids of strain PF2803T. Cultures grown on different (per)deuterated n-alkene, n-alkanol, and n-fatty acid substrates further demonstrate that saturated alkylglycerols are not formed via the reduction of hypothetic alken-1'-yl intermediates. Our results support an unprecedented biosynthetic pathway to monoalkyl/monoacyl- and dialkylglycerols in anaerobic bacteria and suggest that n-alkyl compounds present in the environment can serve as the substrates for supplying the building blocks of ether phospholipids of heterotrophic bacteria. PMID:25724965

  12. Characterization of microbial associations with methanotrophic archaea and sulfate-reducing bacteria through statistical comparison of nested Magneto-FISH enrichments.

    PubMed

    Trembath-Reichert, Elizabeth; Case, David H; Orphan, Victoria J

    2016-01-01

    Methane seep systems along continental margins host diverse and dynamic microbial assemblages, sustained in large part through the microbially mediated process of sulfate-coupled Anaerobic Oxidation of Methane (AOM). This methanotrophic metabolism has been linked to consortia of anaerobic methane-oxidizing archaea (ANME) and sulfate-reducing bacteria (SRB). These two groups are the focus of numerous studies; however, less is known about the wide diversity of other seep associated microorganisms. We selected a hierarchical set of FISH probes targeting a range of Deltaproteobacteria diversity. Using the Magneto-FISH enrichment technique, we then magnetically captured CARD-FISH hybridized cells and their physically associated microorganisms from a methane seep sediment incubation. DNA from nested Magneto-FISH experiments was analyzed using Illumina tag 16S rRNA gene sequencing (iTag). Enrichment success and potential bias with iTag was evaluated in the context of full-length 16S rRNA gene clone libraries, CARD-FISH, functional gene clone libraries, and iTag mock communities. We determined commonly used Earth Microbiome Project (EMP) iTAG primers introduced bias in some common methane seep microbial taxa that reduced the ability to directly compare OTU relative abundances within a sample, but comparison of relative abundances between samples (in nearly all cases) and whole community-based analyses were robust. The iTag dataset was subjected to statistical co-occurrence measures of the most abundant OTUs to determine which taxa in this dataset were most correlated across all samples. Many non-canonical microbial partnerships were statistically significant in our co-occurrence network analysis, most of which were not recovered with conventional clone library sequencing, demonstrating the utility of combining Magneto-FISH and iTag sequencing methods for hypothesis generation of associations within complex microbial communities. Network analysis pointed to many co

  13. Characterization of microbial associations with methanotrophic archaea and sulfate-reducing bacteria through statistical comparison of nested Magneto-FISH enrichments

    DOE PAGESBeta

    Trembath-Reichert, Elizabeth; Case, David H.; Orphan, Victoria J.

    2016-04-18

    Methane seep systems along continental margins host diverse and dynamic microbial assemblages, sustained in large part through the microbially mediated process of sulfate-coupled Anaerobic Oxidation of Methane (AOM). This methanotrophic metabolism has been linked to consortia of anaerobic methane-oxidizing archaea (ANME) and sulfate-reducing bacteria (SRB). These two groups are the focus of numerous studies; however, less is known about the wide diversity of other seep associated microorganisms. We selected a hierarchical set of FISH probes targeting a range ofDeltaproteobacteriadiversity. Using the Magneto-FISH enrichment technique, we then magnetically captured CARD-FISH hybridized cells and their physically associated microorganisms from a methane seepmore » sediment incubation. DNA from nested Magneto-FISH experiments was analyzed using Illumina tag 16S rRNA gene sequencing (iTag). Enrichment success and potential bias with iTag was evaluated in the context of full-length 16S rRNA gene clone libraries, CARD-FISH, functional gene clone libraries, and iTag mock communities. We determined commonly used Earth Microbiome Project (EMP) iTAG primers introduced bias in some common methane seep microbial taxa that reduced the ability to directly compare OTU relative abundances within a sample, but comparison of relative abundances between samples (in nearly all cases) and whole community-based analyses were robust. The iTag dataset was subjected to statistical co-occurrence measures of the most abundant OTUs to determine which taxa in this dataset were most correlated across all samples. In addition, many non-canonical microbial partnerships were statistically significant in our co-occurrence network analysis, most of which were not recovered with conventional clone library sequencing, demonstrating the utility of combining Magneto-FISH and iTag sequencing methods for hypothesis generation of associations within complex microbial communities. Network analysis pointed

  14. Characterization of microbial associations with methanotrophic archaea and sulfate-reducing bacteria through statistical comparison of nested Magneto-FISH enrichments

    PubMed Central

    Case, David H.

    2016-01-01

    Methane seep systems along continental margins host diverse and dynamic microbial assemblages, sustained in large part through the microbially mediated process of sulfate-coupled Anaerobic Oxidation of Methane (AOM). This methanotrophic metabolism has been linked to consortia of anaerobic methane-oxidizing archaea (ANME) and sulfate-reducing bacteria (SRB). These two groups are the focus of numerous studies; however, less is known about the wide diversity of other seep associated microorganisms. We selected a hierarchical set of FISH probes targeting a range of Deltaproteobacteria diversity. Using the Magneto-FISH enrichment technique, we then magnetically captured CARD-FISH hybridized cells and their physically associated microorganisms from a methane seep sediment incubation. DNA from nested Magneto-FISH experiments was analyzed using Illumina tag 16S rRNA gene sequencing (iTag). Enrichment success and potential bias with iTag was evaluated in the context of full-length 16S rRNA gene clone libraries, CARD-FISH, functional gene clone libraries, and iTag mock communities. We determined commonly used Earth Microbiome Project (EMP) iTAG primers introduced bias in some common methane seep microbial taxa that reduced the ability to directly compare OTU relative abundances within a sample, but comparison of relative abundances between samples (in nearly all cases) and whole community-based analyses were robust. The iTag dataset was subjected to statistical co-occurrence measures of the most abundant OTUs to determine which taxa in this dataset were most correlated across all samples. Many non-canonical microbial partnerships were statistically significant in our co-occurrence network analysis, most of which were not recovered with conventional clone library sequencing, demonstrating the utility of combining Magneto-FISH and iTag sequencing methods for hypothesis generation of associations within complex microbial communities. Network analysis pointed to many co

  15. Identification of bacteria in enrichment cultures of sulfate reducers in the Cariaco Basin water column employing Denaturing Gradient Gel Electrophoresis of 16S ribosomal RNA gene fragments

    PubMed Central

    2013-01-01

    Background The Cariaco Basin is characterized by pronounced and predictable vertical layering of microbial communities dominated by reduced sulfur species at and below the redox transition zone. Marine water samples were collected in May, 2005 and 2006, at the sampling stations A (10°30′ N, 64°40′ W), B (10°40′ N, 64°45′ W) and D (10°43’N, 64°32’W) from different depths, including surface, redox interface, and anoxic zones. In order to enrich for sulfate reducing bacteria (SRB), water samples were inoculated into anaerobic media amended with lactate or acetate as carbon source. To analyze the composition of enrichment cultures, we performed DNA extraction, PCR-DGGE, and sequencing of selected bands. Results DGGE results indicate that many bacterial genera were present that are associated with the sulfur cycle, including Desulfovibrio spp., as well as heterotrophs belonging to Vibrio, Enterobacter, Shewanella, Fusobacterium, Marinifilum, Mariniliabilia, and Spirochaeta. These bacterial populations are related to sulfur coupling and carbon cycles in an environment of variable redox conditions and oxygen availability. Conclusions In our studies, we found an association of SRB-like Desulfovibrio with Vibrio species and other genera that have a previously defined relevant role in sulfur transformation and coupling of carbon and sulfur cycles in an environment where there are variable redox conditions and oxygen availability. This study provides new information about microbial species that were culturable on media for SRB at anaerobic conditions at several locations and water depths in the Cariaco Basin. PMID:23981583

  16. Acetate Production from Oil under Sulfate-Reducing Conditions in Bioreactors Injected with Sulfate and Nitrate

    PubMed Central

    Callbeck, Cameron M.; Agrawal, Akhil

    2013-01-01

    Oil production by water injection can cause souring in which sulfate in the injection water is reduced to sulfide by resident sulfate-reducing bacteria (SRB). Sulfate (2 mM) in medium injected at a rate of 1 pore volume per day into upflow bioreactors containing residual heavy oil from the Medicine Hat Glauconitic C field was nearly completely reduced to sulfide, and this was associated with the generation of 3 to 4 mM acetate. Inclusion of 4 mM nitrate inhibited souring for 60 days, after which complete sulfate reduction and associated acetate production were once again observed. Sulfate reduction was permanently inhibited when 100 mM nitrate was injected by the nitrite formed under these conditions. Pulsed injection of 4 or 100 mM nitrate inhibited sulfate reduction temporarily. Sulfate reduction resumed once nitrate injection was stopped and was associated with the production of acetate in all cases. The stoichiometry of acetate formation (3 to 4 mM formed per 2 mM sulfate reduced) is consistent with a mechanism in which oil alkanes and water are metabolized to acetate and hydrogen by fermentative and syntrophic bacteria (K. Zengler et al., Nature 401:266–269, 1999), with the hydrogen being used by SRB to reduce sulfate to sulfide. In support of this model, microbial community analyses by pyrosequencing indicated SRB of the genus Desulfovibrio, which use hydrogen but not acetate as an electron donor for sulfate reduction, to be a major community component. The model explains the high concentrations of acetate that are sometimes found in waters produced from water-injected oil fields. PMID:23770914

  17. NATURAL RELATIONSHIPS AMONG SULFATE-REDUCING EUBACTERIA

    EPA Science Inventory

    Phylogenetic relationships among 20 nonsporeforming and two endospore-forming species of sulfate-reducing eubacteria were inferred from comparative 16S rRNA seguencing. ll genera of mesophilic sulfate-reducing eubacteria except the new genus Desulfomicrobium and the gliding Desul...

  18. Decoupled distance-decay patterns between dsrA and 16S rRNA genes among salt marsh sulfate-reducing bacteria.

    PubMed

    Angermeyer, Angus; Crosby, Sarah C; Huber, Julie A

    2016-01-01

    In many habitats, microorganisms exhibit significant distance-decay patterns as determined by analysis of the 16S rRNA gene and various other genetic elements. However, there have been few studies that examine how the similarities of both taxonomic and functional genes co-vary over geographic distance within a group of ecologically related microbes. Here, we determined the biogeographic patterns of the functional dissimilatory sulfite reductase gene (dsrA) and the 16S rRNA gene in sulfate-reducing bacterial communities of US East Coast salt marsh sediments. Distance-decay, ordination and statistical analyses revealed that the distribution of 16S rRNA genes is strongly influenced by geographic distance and environmental factors, whereas the dsrA gene is not. Together, our results indicate that 16S rRNA genes are likely dispersal limited and under environmental selection, whereas dsrA genes appear randomly distributed and not selected for by any expected environmental variables. Selection, drift, dispersal and mutation are all factors that may help explain the decoupled biogeographic patterns for the two genes. These data suggest that both the taxonomic and functional elements of microbial communities should be considered in future studies of microbial biogeography to aid in our understanding of the diversity, distribution and function of microorganisms in the environment. PMID:25727503

  19. Antimicrobial action and anti-corrosion effect against sulfate reducing bacteria by lemongrass (Cymbopogon citratus) essential oil and its major component, the citral

    PubMed Central

    2013-01-01

    The anti-corrosion effect and the antimicrobial activity of lemongrass essential oil (LEO) against the planktonic and sessile growth of a sulfate reducing bacterium (SRB) were evaluated. Minimum inhibitory concentration (MIC) of LEO and its major component, the citral, was 0.17 mg ml-1. In addition, both LEO and citral showed an immediate killing effect against SRB in liquid medium, suggesting that citral is responsible for the antimicrobial activity of LEO against SRB. Transmission electron microscopy revealed that the MIC of LEO caused discernible cell membrane alterations and formed electron-dense inclusions. Neither biofilm formation nor corrosion was observed on carbon steel coupons after LEO treatment. LEO was effective for the control of the planktonic and sessile SRB growth and for the protection of carbon steel coupons against biocorrosion. The application of LEO as a potential biocide for SRB growth control in petroleum reservoirs and, consequently, for souring prevention, and/or as a coating protection against biocorrosion is of great interest for the petroleum industries. PMID:23938023

  20. Antimicrobial action and anti-corrosion effect against sulfate reducing bacteria by lemongrass (Cymbopogon citratus) essential oil and its major component, the citral.

    PubMed

    Korenblum, Elisa; Regina de Vasconcelos Goulart, Fátima; de Almeida Rodrigues, Igor; Abreu, Fernanda; Lins, Ulysses; Alves, Péricles Barreto; Blank, Arie Fitzgerald; Valoni, Erika; Sebastián, Gina V; Alviano, Daniela Sales; Alviano, Celuta Sales; Seldin, Lucy

    2013-01-01

    The anti-corrosion effect and the antimicrobial activity of lemongrass essential oil (LEO) against the planktonic and sessile growth of a sulfate reducing bacterium (SRB) were evaluated. Minimum inhibitory concentration (MIC) of LEO and its major component, the citral, was 0.17 mg ml-1. In addition, both LEO and citral showed an immediate killing effect against SRB in liquid medium, suggesting that citral is responsible for the antimicrobial activity of LEO against SRB. Transmission electron microscopy revealed that the MIC of LEO caused discernible cell membrane alterations and formed electron-dense inclusions. Neither biofilm formation nor corrosion was observed on carbon steel coupons after LEO treatment. LEO was effective for the control of the planktonic and sessile SRB growth and for the protection of carbon steel coupons against biocorrosion. The application of LEO as a potential biocide for SRB growth control in petroleum reservoirs and, consequently, for souring prevention, and/or as a coating protection against biocorrosion is of great interest for the petroleum industries. PMID:23938023

  1. Draft Genome Sequence of a Novel Desulfobacteraceae Member from a Sulfate-Reducing Bioreactor Metagenome

    PubMed Central

    Pinto, Ameet J.; Figueroa, Linda A.; Sharp, Jonathan O.

    2016-01-01

    Sulfate-reducing bacteria are important players in the global sulfur cycle and of considerable commercial interest. The draft genome sequence of a sulfate-reducing bacterium of the family Desulfobacteraceae, assembled from a sulfate-reducing bioreactor metagenome, indicates that heavy-metal– and acid-resistance traits of this organism may be of importance for its application in acid mine drainage mitigation. PMID:26769931

  2. Draft Genome Sequence of a Novel Desulfobacteraceae Member from a Sulfate-Reducing Bioreactor Metagenome.

    PubMed

    Almstrand, Robert; Pinto, Ameet J; Figueroa, Linda A; Sharp, Jonathan O

    2016-01-01

    Sulfate-reducing bacteria are important players in the global sulfur cycle and of considerable commercial interest. The draft genome sequence of a sulfate-reducing bacterium of the family Desulfobacteraceae, assembled from a sulfate-reducing bioreactor metagenome, indicates that heavy-metal- and acid-resistance traits of this organism may be of importance for its application in acid mine drainage mitigation. PMID:26769931

  3. IN SITU RT-PCR WITH A SULFATE-REDUCING BACTERIUM ISOLATED FROM SEAGRASS ROOTS

    EPA Science Inventory

    Bacteria considered to be obligate anaerobes internally colonize roots of the submerged macrophyte Halodule wrightii. A sulfate reducing bacterium, Summer lac 1, was isolated on lactate from H. wrightii roots. The isolate has physiological characteristics typical of Desulfovibri...

  4. Diverse Oxidative Stress Resistance Mechanisms in Sulfate-reducing Bacteria as Revealed by Global Analysis of the Impact of H2O2 Exposure on Desulfovibrio vulgaris Hildenborough

    NASA Astrophysics Data System (ADS)

    Zhou, A.; Mukhopadhyay, A.; He, Z.; Hemme, C. L.; Keasling, J. D.; Arkin, A. P.; Hazen, T. C.; Wall, J. D.; Zhou, J.

    2008-12-01

    Desulfovibrio vulgaris Hildenborough (DvH) plays important roles in the bioremediation of toxic metals. It has been shown aero-tolerant. In order to understand the molecular mechanism of DvH oxidative stress response, mid-log DvH cells were subjected to 1 mM of H2O2 and the transcriptomic changes were examined at 30, 60, 120, 240 and 480 min. The microarray data demonstrated that the gene expression was extensively affected with 29% of genes in the genome significantly up- or down-regulated after 120-min H2O2 treatment. In response to elevated cellular H2O2, expression of thiol-peroxidase genes ahpC and bcp were increased in addition to the significant induction of many thioredoxin reductase and thioredoxin genes, which represent the thiol switch in the oxidative stress response. Increased gene expression PerR regulon genes including PerR itself provided evidence for the regulatory role of PerR in oxidative stress response. The role of Fur was suggested by the significant up-regulation of Fur regulon genes. In terms of the H2O2 scavenging enzymes, different from the stress response to air where both rbr and rbr2 were induced, only rbr2 was up-regulated in response to H2O2; together with up-regulated rdl, they might be the additional players for the detoxification of H2O2. Superoxide scavenging enzyme katA was significantly down-regulated, which is in contrast to its role in facultative microbes such as E.coli and B. subtilis. The links between the up- regulated genes involved in H2O2 scavenging, protein fate, DNA metabolism and lipid metabolism and the down-regulated genes involved in sulfate reduction, energy production and translation were demonstrated by the gene co-expression network. The proteomics data provided further evidence in translation level and complemented the transcriptomics data. Taken together, the cellular response of D. vulgaris Hildenborough to H2O2 was the up-regulation of detoxification, protein and DNA repair systems and the down

  5. Reduction of selenate to selenide by sulfate-respiring bacteria: Experiments with cell suspensions and estuarine sediments

    USGS Publications Warehouse

    Zehr, J.P.; Oremland, R.S.

    1987-01-01

    Washed cell suspension of Desulfovibrio desulfuricans subsp. aestuarii were capable of reducing nanomolar levels of selenate to selenide as well as sulfate to sulfide. Reduction of these species was inhibited by 1 mM selenate or tungstate. The addition of 1 mM sulfate decreased the reduction of selenate and enhanced the reduction of sulfate. Increasing concentrations of sulfate inhibited rates of selenate reduction but enhanced sulfate reduction rates. Cell suspensions kept in 1 mM selenate were incapable of reducing either selenate or sulfate when the selenate/sulfate ratio was ???0.02, indicating that irreversible inhibition occurs at high selenate concentrations. Anoxic estuarine sediments having an active flora of sulfate-respiring bacteria were capable of a small amount of selenate reduction when ambient sulfate concentrations were low (<4 mM). These results indicate that sulfate is an inhibitor of the reduction of trace qunatitites of selenate. Therefore, direct reduction of traces of selenate to selenide by sulfate-respiring bacteria in natural environments is constrained by the ambient concentration of sulfate ions. The significance of this observation with regard to the role sediments play in sequestering selenium is discussed

  6. Bioinformatics comparison of sulfate-reducing metabolism nucleotide sequences

    NASA Astrophysics Data System (ADS)

    Tremberger, G.; Dehipawala, Sunil; Nguyen, A.; Cheung, E.; Sullivan, R.; Holden, T.; Lieberman, D.; Cheung, T.

    2015-09-01

    The sulfate-reducing bacteria can be traced back to 3.5 billion years ago. The thermodynamics details of the sulfur cycle have been well documented. A recent sulfate-reducing bacteria report (Robator, Jungbluth, et al , 2015 Jan, Front. Microbiol) with Genbank nucleotide data has been analyzed in terms of the sulfite reductase (dsrAB) via fractal dimension and entropy values. Comparison to oil field sulfate-reducing sequences was included. The AUCG translational mass fractal dimension versus ATCG transcriptional mass fractal dimension for the low temperature dsrB and dsrA sequences reported in Reference Thirteen shows correlation R-sq ~ 0.79 , with a probably of about 3% in simulation. A recent report of using Cystathionine gamma-lyase sequence to produce CdS quantum dot in a biological method, where the sulfur is reduced just like in the H2S production process, was included for comparison. The AUCG mass fractal dimension versus ATCG mass fractal dimension for the Cystathionine gamma-lyase sequences was found to have R-sq of 0.72, similar to the low temperature dissimilatory sulfite reductase dsr group with 3% probability, in contrary to the oil field group having R-sq ~ 0.94, a high probable outcome in the simulation. The other two simulation histograms, namely, fractal dimension versus entropy R-sq outcome values, and di-nucleotide entropy versus mono-nucleotide entropy R-sq outcome values are also discussed in the data analysis focusing on low probability outcomes.

  7. Streptomyces lunalinharesii 235 prevents the formation of a sulfate-reducing bacterial biofilm.

    PubMed

    Rosa, Juliana Pacheco da; Tibúrcio, Samyra Raquel Gonçalves; Marques, Joana Montezano; Seldin, Lucy; Coelho, Rosalie Reed Rodrigues

    2016-01-01

    Streptomyces lunalinharesii strain 235 produces an antimicrobial substance that is active against sulfate reducing bacteria, the major bacterial group responsible for biofilm formation and biocorrosion in petroleum reservoirs. The use of this antimicrobial substance for sulfate reducing bacteria control is therefore a promising alternative to chemical biocides. In this study the antimicrobial substance did not interfere with the biofilm stability, but the sulfate reducing bacteria biofilm formation was six-fold smaller in carbon steel coupons treated with the antimicrobial substance when compared to the untreated control. A reduction in the most probable number counts of planktonic cells of sulfate reducing bacteria was observed after treatments with the sub-minimal inhibitory concentration, minimal inhibitory concentration, and supra-minimal inhibitory concentration of the antimicrobial substance. Additionally, when the treated coupons were analyzed by scanning electron microscopy, the biofilm formation was found to be substantially reduced when the supra-minimal inhibitory concentration of the antimicrobial substance was used. The coupons used for the biofilm formation had a small weight loss after antimicrobial substance treatment, but corrosion damage was not observed by scanning electron microscopy. The absence of the dsrA gene fragment in the scraped cell suspension after treatment with the supra-minimal inhibitory concentration of the antimicrobial substance suggests that Desulfovibrio alaskensis was not able to adhere to the coupons. This is the first report on an antimicrobial substance produced by Streptomyces active against sulfate reducing bacteria biofilm formation. The application of antimicrobial substance as a potential biocide for sulfate reducing bacteria growth control could be of great interest to the petroleum industry. PMID:27266627

  8. Structural and functional dynamics of sulfate-reducing populations in bacterial biofilms

    SciTech Connect

    Santegoeds, C.M.; Ferdelman, T.G.; Muyzer, G.; Beer, D. de

    1998-10-01

    The authors describe the combined application of microsensors and molecular techniques to investigate the development of sulfate reduction and of sulfate-reducing bacterial populations in an aerobic bacterial biofilm. Microsensor measurements for oxygen showed that anaerobic zones developed in the biofilm within 1 week and that oxygen was depleted in the top 200 to 400 {micro}m during all stages of biofilm development. Sulfate reduction was first detected after 6 weeks of growth, although favorable conditions for growth of sulfate-reducing bacteria (SRB) were present from the first week. In situ hybridization with a 16S rRNA probe for SRB revealed that sulfate reducers were present in high numbers in all stages of development, both in the oxic and anoxic zones of the biofilm. Denaturing gradient gel electrophoresis (DGGE) showed that the genetic diversity of the microbial community increased during the development of the biofilm. Hybridization analysis of the DGGE profiles with taxon-specific oligonucleotide probes showed that Desulfobulbus and Desulfovibrio were the main sulfate-reducing bacteria in all biofilm samples as well as in the bulk activated sludge. However, different Desulfobulbus and Desulfovibrio species were found in the 6th and 8th weeks of incubation, respectively, coinciding with the development of sulfate reduction. Their data indicate that not all SRB detected by molecular analysis were sulfidogenically active in the biofilm.

  9. Diversity of Sulfur Isotope Fractionations by Sulfate-Reducing Prokaryotes†

    PubMed Central

    Detmers, Jan; Brüchert, Volker; Habicht, Kirsten S.; Kuever, Jan

    2001-01-01

    Batch culture experiments were performed with 32 different sulfate-reducing prokaryotes to explore the diversity in sulfur isotope fractionation during dissimilatory sulfate reduction by pure cultures. The selected strains reflect the phylogenetic and physiologic diversity of presently known sulfate reducers and cover a broad range of natural marine and freshwater habitats. Experimental conditions were designed to achieve optimum growth conditions with respect to electron donors, salinity, temperature, and pH. Under these optimized conditions, experimental fractionation factors ranged from 2.0 to 42.0‰. Salinity, incubation temperature, pH, and phylogeny had no systematic effect on the sulfur isotope fractionation. There was no correlation between isotope fractionation and sulfate reduction rate. The type of dissimilatory bisulfite reductase also had no effect on fractionation. Sulfate reducers that oxidized the carbon source completely to CO2 showed greater fractionations than sulfate reducers that released acetate as the final product of carbon oxidation. Different metabolic pathways and variable regulation of sulfate transport across the cell membrane all potentially affect isotope fractionation. Previous models that explained fractionation only in terms of sulfate reduction rates appear to be oversimplified. The species-specific physiology of each sulfate reducer thus needs to be taken into account to understand the regulation of sulfur isotope fractionation during dissimilatory sulfate reduction. PMID:11157259

  10. Characterizing the non-reducing end structure of heparan sulfate.

    PubMed

    Wu, Zhengliang L; Lech, Miroslaw

    2005-10-01

    The reducing end of heparan sulfate has been known for a long time, but information on the non-reducing end has been lacking. Recent studies indicate that the non-reducing end of heparan sulfate might be the place where fibroblast growth factor signaling complex forms. The non-reducing end also changes with heparanase digestion and, thus, might serve as a marker for tumor pathology. Using high performance liquid chromatography-coupled mass spectrometry, we have identified and characterized the non-reducing end of bovine kidney heparan sulfate. We find that the non-reducing end region is highly sulfated and starts with a glucuronic acid (GlcA) residue. The likely sequence of the non-reducing end hexasaccharides is GlcA-GlcNS6S-UA+/-2S-GlcNS+/-6S-Ido2S-GlcNS+/-6S (where GlcNS is N-sulfate-D-glucosamine, S is sulfate, UA is uronic acid, and Ido is iduronic acid). Our data suggests that the non-reducing end of bovine kidney heparan sulfate is not trimmed by heparanase and is capable of supporting fibroblast growth factor signaling complex formation. PMID:16079142

  11. Phylogenetic analysis of dissimilatory Fe(III)-reducing bacteria

    USGS Publications Warehouse

    Lonergan, D.J.; Jenter, H.L.; Coates, J.D.; Phillips, E.J.P.; Schmidt, T.M.; Lovley, D.R.

    1996-01-01

    Evolutionary relationships among strictly anaerobic dissimilatory Fe(III)- reducing bacteria obtained from a diversity of sedimentary environments were examined by phylogenetic analysis of 16S rRNA gene sequences. Members of the genera Geobacter, Desulfuromonas, Pelobacter, and Desulfuromusa formed a monophyletic group within the delta subdivision of the class Proteobacteria. On the basis of their common ancestry and the shared ability to reduce Fe(III) and/or S0, we propose that this group be considered a single family, Geobacteraceae. Bootstrap analysis, characteristic nucleotides, and higher- order secondary structures support the division of Geobacteraceae into two subgroups, designated the Geobacter and Desulfuromonas clusters. The genus Desulfuromusa and Pelobacter acidigallici make up a distinct branch with the Desulfuromonas cluster. Several members of the family Geobacteraceae, none of which reduce sulfate, were found to contain the target sequences of probes that have been previously used to define the distribution of sulfate-reducing bacteria and sulfate-reducing bacterium-like microorganisms. The recent isolations of Fe(III)-reducing microorganisms distributed throughout the domain Bacteria suggest that development of 16S rRNA probes that would specifically target all Fe(III) reducers may not be feasible. However, all of the evidence suggests that if a 16S rRNA sequence falls within the family Geobacteraceae, then the organism has the capacity for Fe(III) reduction. The suggestion, based on geological evidence, that Fe(III) reduction was the first globally significant process for oxidizing organic matter back to carbon dioxide is consistent with the finding that acetate-oxidizing Fe(III) reducers are phylogenetically diverse.

  12. Phylogenetic analysis of dissimilatory Fe(III)-reducing bacteria.

    PubMed Central

    Lonergan, D J; Jenter, H L; Coates, J D; Phillips, E J; Schmidt, T M; Lovley, D R

    1996-01-01

    Evolutionary relationships among strictly anaerobic dissimilatory Fe(III)-reducing bacteria obtained from a diversity of sedimentary environments were examined by phylogenetic analysis of 16S rRNA gene sequences. Members of the genera Geobacter, Desulfuromonas, Pelobacter, and Desulfuromusa formed a monophyletic group within the delta subdivision of the class Proteobacteria. On the basis of their common ancestry and the shared ability to reduce Fe(III) and/or S0, we propose that this group be considered a single family, Geobacteraceae. Bootstrap analysis, characteristic nucleotides, and higher-order secondary structures support the division of Geobacteraceae into two subgroups, designated the Geobacter and Desulfuromonas clusters. The genus Desulfuromusa and Pelobacter acidigallici make up a distinct branch within the Desulfuromonas cluster. Several members of the family Geobacteraceae, none of which reduce sulfate, were found to contain the target sequences of probes that have been previously used to define the distribution of sulfate-reducing bacteria and sulfate-reducing bacterium-like microorganisms. The recent isolations of Fe(III)-reducing microorganisms distributed throughout the domain Bacteria suggest that development of 16S rRNA probes that would specifically target all Fe(III) reducers may not be feasible. However, all of the evidence suggests that if a 16S rRNA sequence falls within the family Geobacteraceae, then the organism has the capacity for Fe(III) reduction. The suggestion, based on geological evidence, that Fe(III) reduction was the first globally significant process for oxidizing organic matter back to carbon dioxide is consistent with the finding that acetate-oxidizing Fe(III) reducers are phylogenetically diverse. PMID:8636045

  13. Organoheterotrophic Bacterial Abundance Associates with Zinc Removal in Lignocellulose-Based Sulfate-Reducing Systems.

    PubMed

    Drennan, Dina M; Almstrand, Robert; Lee, Ilsu; Landkamer, Lee; Figueroa, Linda; Sharp, Jonathan O

    2016-01-01

    Syntrophic relationships between fermentative and sulfate-reducing bacteria are essential to lignocellulose-based systems applied to the passive remediation of mining-influenced waters. In this study, seven pilot-scale sulfate-reducing bioreactor columns containing varying ratios of alfalfa hay, pine woodchips, and sawdust were analyzed over ∼500 days to investigate the influence of substrate composition on zinc removal and microbial community structure. Columns amended with >10% alfalfa removed significantly more sulfate and zinc than did wood-based columns. Enumeration of sulfate reducers by functional signatures (dsrA) and their putative identification from 16S rRNA genes did not reveal significant correlations with zinc removal, suggesting limitations in this directed approach. In contrast, a strong indicator of zinc removal was discerned in comparing the relative abundance of core microorganisms shared by all reactors (>80% of total community), many of which had little direct involvement in metal or sulfate respiration. The relative abundance of Desulfosporosinus, the dominant putative sulfate reducer within these reactors, correlated to representatives of this core microbiome. A subset of these clades, including Treponema, Weissella, and Anaerolinea, was associated with alfalfa and zinc removal, and the inverse was found for a second subset whose abundance was associated with wood-based columns, including Ruminococcus, Dysgonomonas, and Azospira. The construction of a putative metabolic flowchart delineated syntrophic interactions supporting sulfate reduction and suggests that the production of and competition for secondary fermentation byproducts, such as lactate scavenging, influence bacterial community composition and reactor efficacy. PMID:26605699

  14. Medicinal smoke reduces airborne bacteria.

    PubMed

    Nautiyal, Chandra Shekhar; Chauhan, Puneet Singh; Nene, Yeshwant Laxman

    2007-12-01

    This study represents a comprehensive analysis and scientific validation of our ancient knowledge about the effect of ethnopharmacological aspects of natural products' smoke for therapy and health care on airborne bacterial composition and dynamics, using the Biolog microplate panels and Microlog database. We have observed that 1h treatment of medicinal smoke emanated by burning wood and a mixture of odoriferous and medicinal herbs (havan sámagri=material used in oblation to fire all over India), on aerial bacterial population caused over 94% reduction of bacterial counts by 60 min and the ability of the smoke to purify or disinfect the air and to make the environment cleaner was maintained up to 24h in the closed room. Absence of pathogenic bacteria Corynebacterium urealyticum, Curtobacterium flaccumfaciens, Enterobacter aerogenes (Klebsiella mobilis), Kocuria rosea, Pseudomonas syringae pv. persicae, Staphylococcus lentus, and Xanthomonas campestris pv. tardicrescens in the open room even after 30 days is indicative of the bactericidal potential of the medicinal smoke treatment. We have demonstrated that using medicinal smoke it is possible to completely eliminate diverse plant and human pathogenic bacteria of the air within confined space. PMID:17913417

  15. Biological sulfate reduction in the acidogenic phase of anaerobic digestion under dissimilatory Fe (III)--reducing conditions.

    PubMed

    Zhang, Jingxin; Zhang, Yaobin; Chang, Jinghui; Quan, Xie; Li, Qi

    2013-04-15

    In this study, a novel approach was developed for sulfate - containing wastewater treatment via dosing Fe₂O₃ in a two - stage anaerobic reactor (A1, S1). The addition of Fe₂O₃ in its second stage i.e. acidogenic sulfate-reducing reactor (S1) resulted in microbial reduction of Fe (III), which significantly enhanced the biological sulfate reduction. In reactor S1, increasing influent sulfate concentration to 1400 mg/L resulted in a higher COD removal (27.3%) and sulfate reduction (57.9%). In the reference reactor without using Fe₂O₃ (S2), the COD and sulfate removal were 15.6% and 29%, respectively. The combined performance of the two-stage anaerobic reactor (A1, S1) also showed a higher COD removal of 74.2%. Denaturing gradient gel electrophoresis (DGGE) and phylogenetic analysis showed that the dominant bacteria with high similarity to IRB species as well as sulfate reducer Desulfovibrio and acidogenic bacteria (AB) were enriched in S1. Quantitative Polymerase Chain Reaction (qPCR) analysis presented a higher proportion of sulfate reducer Desulfovibrio marrakechensis and Fe (III) reducer Iron-reducing bacteria HN54 in S1. PMID:23411038

  16. Effect of dietary copper sulfate, Aureo SP250, or clinoptilolite on ureolytic bacteria found in the pig large intestine.

    PubMed Central

    Varel, V H; Robinson, I M; Pond, W G

    1987-01-01

    The predominant ureolytic bacteria in the pig large intestine were determined while growing pigs were fed a basal diet or basal diet plus copper sulfate, Aureo SP250, or clinoptilolite. Fecal samples were collected from four pigs fed each diet at 3, 9, and 14 weeks and analyzed for total colony counts and percent ureolytic bacteria. Fecal urease activity, ammonia nitrogen, and identity of the ureolytic bacteria were determined at 14 weeks. Copper sulfate and Aureo SP250 reduced the number of ureolytic organisms, with a marked decrease occurring in the Streptococcus spp., which made up 74% of the ureolytic isolates from the pigs on the basal diet. Other ureolytic species detected at lower concentrations were Staphylococcus spp., Selenomonas ruminantium, Bacteroides multiacidus, and Eubacterium limosum. Copper sulfate also reduced fecal urease activity (P less than 0.10). Fecal ammonia concentrations were not different between pigs fed the various diets. These data suggest that the streptococci are the most numerous ureolytic species in the pig intestinal tract and are significantly reduced by copper sulfate and Aureo SP250; however, only copper sulfate reduced intestinal urease activity. PMID:2823707

  17. Effect of dietary copper sulfate, Aureo SP250, or clinoptilolite on ureolytic bacteria found in the pig large intestine.

    PubMed

    Varel, V H; Robinson, I M; Pond, W G

    1987-09-01

    The predominant ureolytic bacteria in the pig large intestine were determined while growing pigs were fed a basal diet or basal diet plus copper sulfate, Aureo SP250, or clinoptilolite. Fecal samples were collected from four pigs fed each diet at 3, 9, and 14 weeks and analyzed for total colony counts and percent ureolytic bacteria. Fecal urease activity, ammonia nitrogen, and identity of the ureolytic bacteria were determined at 14 weeks. Copper sulfate and Aureo SP250 reduced the number of ureolytic organisms, with a marked decrease occurring in the Streptococcus spp., which made up 74% of the ureolytic isolates from the pigs on the basal diet. Other ureolytic species detected at lower concentrations were Staphylococcus spp., Selenomonas ruminantium, Bacteroides multiacidus, and Eubacterium limosum. Copper sulfate also reduced fecal urease activity (P less than 0.10). Fecal ammonia concentrations were not different between pigs fed the various diets. These data suggest that the streptococci are the most numerous ureolytic species in the pig intestinal tract and are significantly reduced by copper sulfate and Aureo SP250; however, only copper sulfate reduced intestinal urease activity. PMID:2823707

  18. Oxidation of polycyclic aromatic hydrocarbons under sulfate-reducing conditions

    USGS Publications Warehouse

    Coates, J.D.; Anderson, R.T.; Lovley, D.R.

    1996-01-01

    [14C]naphthalene and phenanthrene were oxidized to 14CO2 without a detectable lag under strict anaerobic conditions in sediments from San Diego Bay, San Diego, Calif., that were heavily contaminated with polycyclic aromatic hydrocarbons (PAHs) but not in less contaminated sediments. Sulfate reduction was necessary for PAH oxidation. These results suggest that the self-purification capacity of PAH-contaminated sulfate-reducing environments may be greater than previously recognized.

  19. Use of sulfate reducing cell suspension bioreactors for the treatment of SO2 rich flue gases.

    PubMed

    Lens, P N L; Gastesi, R; Lettinga, G

    2003-06-01

    This paper describes a novel bioscrubber concept for biological flue gas desulfurization, based on the recycling of a cell suspension of sulfite/sulfate reducing bacteria between a scrubber and a sulfite/sulfate reducing hydrogen fed bioreactor. Hydrogen metabolism in sulfite/sulfate reducing cell suspensions was investigated using batch activity tests and by operating a completely stirred tank reactor (CSTR). The maximum specific hydrogenotrophic sulfite/sulfate reduction rate increased with 10% and 300%, respectively, by crushing granular inoculum sludge and by cultivation of this sludge as cell suspension in a CSTR. Operation of a sulfite fed CSTR (hydraulic retention time 4 days; pH 7.0; sulfite loading rate 0.5-1.5 g SO3(2-) l(-1) d(-1)) with hydrogen as electron donor showed that high (up to 1.6 g l(-1)) H2S concentrations can be obtained within 10 days of operation. H2S inhibition, however, limited the sulfite reducing capacity of the CSTR. Methane production by the cell suspension disappeared within 20 days reactor operation. The outcompetition of methanogens in excess of H2 can be attributed to CO2 limitation and/or to sulfite or sulfide toxicity. The use of cell suspensions opens perspectives for monolith or packed bed reactor configurations, which have a much lower pressure drop compared to air lift reactors, to supply H2 to sulfite/sulfate reducing bioreactors. PMID:12889613

  20. Field and laboratory studies of methane oxidation in an anoxic marine sediment: Evidence for a methanogen-sulfate reducer consortium

    SciTech Connect

    Hoehler, T.M.; Alperin, M.J.; Albert, D.B.

    1994-12-01

    Field and laboratory studies of anoxic sediments from Cape Lookout Bight, North Carolina, suggest that anaerobic methane oxidation is mediated by a consortium of methanogenic and sulfate-reducing bacteria. A seasonal survey of methane oxidation and CO{sub 2} reduction rates indicates that methane production was confined to sulfate-depleted sediments at all times of year, while methane oxidation occurred in two modes. In the summer, methane oxidation was confined to sulfate-depleted sediments and occurred at rates lower than those of CO{sub 2} reduction. In the winter, net methane oxidation occurred in an interval at the base of the sulfate-containing zone. Sediment incubation experiments suggest both methanogens and sulfate reducers were responsible for the observed methane oxidation. In one incubation experiment both modes of oxidation were partially inhibited by 2-bromoethanesulfonic acid (a specific inhibitor of methanogens). This evidence, along with the apparent confinement of methane oxidation to sulfate-depleted sediments in the summer, indicates that methanogenic bacteria are involved in methane oxidation. In a second incubation experiment, net methane oxidation was induced by adding sulfate to homogenized methanogenic sediments, suggesting that sulfate reducers also a play a role in the process. We hypothesize that methanogens oxidize methane and produce hydrogen via a reversal of CO{sub 2} reduction. The hydrogen is efficiently removed and maintained at low concentrations by sulfate reducers. Pore water H{sub 2} concentrations in the sediment incubation experiments (while net methane oxidation was occurring) were low enough that methanogenic bacteria could derive sufficient energy for growth from the oxidation of methane. The methanogen-sulfate reducer consortium may also be a feasible mechanism for previously documented anaerobic methane oxidation in both freshwater and marine environments. 63 refs., 6 refs.

  1. Iron reduction and alteration of nontronite NAu-2 by a sulfate-reducing bacterium

    NASA Astrophysics Data System (ADS)

    Li, Yi-Liang; Vali, Hojatollah; Sears, S. Kelly; Yang, John; Deng, Baolin; Zhang, Chuanlun L.

    2004-08-01

    Iron-rich clay minerals are abundant in the natural environment and are an important source of iron for microbial metabolism. The objective of this study was to understand the mechanism(s) of enhanced reduction of Fe(III) in iron-rich 2:1 clay minerals under sulfate-reducing conditions. In particular, biogenic reduction of structural Fe(III) in nontronite NAu-2, an Fe-rich smectite-group mineral, was studied using a Desulfovibrio spp. strain G-11 with or without amended sulfate. The microbial production of Fe(II) from NAu-2 is about 10% of total structural Fe(III) (30 mM) when Fe(III) is available as the sole electron acceptor. The measured production of Fe(II), however, can reach 29% of the total structural Fe(III) during sulfate reduction by G-11 when sulfate (50 mM) is concurrently added with NAu-2. In contrast, abiotic production of Fe(II) from the reaction of NAu-2 with Na 2S (50 mM) is only ca. 7.5% of the total structural Fe(III). The enhanced reduction of structural Fe(III) by G-11, particularly in the presence of sulfate, is closely related to the growth rate and metabolic activities of the bacteria. Analyses by X-ray diffraction, transmission electron microscopy, and energy dispersive spectroscopy reveal significant changes in the structure and composition of NAu-2 during its alteration by bacterial sulfate reduction. G-11 can also derive nutrients from NAu-2 to support its growth in the absence of amended minerals and vitamins. Results of this study suggest that sulfate-reducing bacteria may play a more significant role than previously recognized in the cycling of Fe, S, and other elements during alteration of Fe-rich 2:1 clay minerals and other silicate minerals.

  2. Uranium immobilization by sulfate-reducing biofilms grown on hematite, dolomite, and calcite.

    SciTech Connect

    Marsili, E.; Beyenal, Haluk; Di Palma, L.; Merli, C.; Dohnalkova, Alice; Amonette, James E.; Lewandowski, Zbigniew

    2007-12-15

    Biofilms of sulfate-reducing bacteria Desulfovibrio desulfuricans G20 wereused to reduce dissolved U(VI)and subsequently immobilize U(IV) in the presence of uranium-complexing carbonates. The biofilms were grown in three identically operated fixed bed reactors, filled with three types of minerals: one noncarbonate-bearing mineral(hematite) and two carbonate-bearing minerals (calcite and dolomite). The source of carbonates in the reactors filled with calcite and dolomite were the minerals, while in the reactor filled with hematite it was a 10 mM carbonate buffer, pH 7.2, which we added to the growth medium. Our five-month study demonstrated that the sulfate-reducing biofilms grown in all reactors were able to immobilize/reduce uranium efficiently, despite the presence of uranium-complexing carbonates.

  3. Anaerobic hydrocarbon degradation in petroleum-contaminated harbor sediments under sulfate-reducing and artificially imposed iron-reducing conditions

    USGS Publications Warehouse

    Coates, J.D.; Anderson, R.T.; Woodward, J.C.; Phillips, E.J.P.; Lovley, D.R.

    1996-01-01

    The potential use of iron(III) oxide to stimulate in-situ hydrocarbon degradation in anaerobic petroleum-contaminated harbor sediments was investigated. Previous studies have indicated that Fe(III)-reducing bacteria (FeRB) can oxidize some electron donors more effectively than sulfate- reducing bacteria (SRB). In contrast to previous results in freshwater sediments, the addition of Fe(III) to marine sediments from San Diego Bay, CA did not switch the terminal electron-accepting process (TEAP) from sulfate reduction to Fe-(III) reduction. Addition of Fe(III) also did not stimulate anaerobic hydrocarbon oxidation. Exposure of the sediment to air [to reoxidize Fe(II) to Fe(III)] followed by anaerobic incubation of the sediments, resulted in Fe-(III) reduction as the TEAP, but contaminant degradation was not stimulated and in some instances was inhibited. The difference in the ability of FeRB to compete with the SRB in the different sediment treatments was related to relative population sizes. Although the addition of Fe(III) did not stimulate hydrocarbon degradation, the results presented here as well as other recent studies demonstrate that there may be significant anaerobic hydrocarbon degradation under sulfate-reducing conditions in harbor sediments.

  4. Determination of kinetic coefficients for the simultaneous reduction of sulfate and uranium by Desulfovibrio desulfuricans bacteria

    SciTech Connect

    Tucker, M.D.

    1995-05-01

    Uranium contamination of groundwaters and surface waters near abandoned mill tailings piles is a serious concern in many areas of the western United States. Uranium usually exists in either the U(IV) or the U(VI) oxidation state. U(VI) is soluble in water and, as a result, is very mobile in the environment. U(IV), however, is generally insoluble in water and, therefore, is not subject to aqueous transport. In recent years, researchers have discovered that certain anaerobic microorganisms, such as the sulfate-reducing bacteria Desulfovibrio desulfuricans, can mediate the reduction of U(VI) to U(IV). Although the ability of this microorganism to reduce U(VI) has been studied in some detail by previous researchers, the kinetics of the reactions have not been characterized. The purpose of this research was to perform kinetic studies on Desulfovibrio desulficans bacteria during simultaneous reduction of sulfate and uranium and to determine the phase in which uranium exists after it has been reduced and precipitated from solution. The studies were conducted in a laboratory-scale chemostat under substrate-limited growth conditions with pyruvate as the substrate. Kinetic coefficients for substrate utilization and cell growth were calculated using the Monod equation. The maximum rate of substrate utilization (k) was determined to be 4.70 days{sup {minus}1} while the half-velocity constant (K{sub s}) was 140 mg/l COD. The yield coefficient (Y) was determined to be 0.17 mg cells/mg COD while the endogenous decay coefficient (k{sub d}) was calculated as 0.072 days{sup {minus}1}. After reduction, U(IV) Precipitated from solution in the uraninite (UO{sub 2}) phase. Uranium removal efficiency as high as 90% was achieved in the chemostat.

  5. Characterization of sulfate-reducing granular sludge in the SANI(®) process.

    PubMed

    Hao, Tianwei; Wei, Li; Lu, Hui; Chui, Hokwong; Mackey, Hamish R; van Loosdrecht, Mark C M; Chen, Guanghao

    2013-12-01

    Hong Kong practices seawater toilet flushing covering 80% of the population. A sulfur cycle-based biological nitrogen removal process, the Sulfate reduction, Autotrophic denitrification and Nitrification Integrated (SANI(®)) process, had been developed to close the loop between the hybrid water supply and saline sewage treatment. To enhance this novel process, granulation of a Sulfate-Reducing Up-flow Sludge Bed (SRUSB) reactor has recently been conducted for organic removal and provision of electron donors (sulfide) for subsequent autotrophic denitrification, with a view to minimizing footprint and maximizing operation resilience. This further study was focused on the biological and physicochemical characteristics of the granular sulfate-reducing sludge. A lab-scale SRUSB reactor seeded with anaerobic digester sludge was operated with synthetic saline sewage for 368 days. At 1 h nominal hydraulic retention time (HRT) and 6.4 kg COD/m(3)-d organic loading rate, the SRUSB reactor achieved 90% COD and 75% sulfate removal efficiencies. Granular sludge was observed within 30 days, and became stable after 4 months of operation with diameters of 400-500 μm, SVI5 of 30 ml/g, and extracellular polymeric substances of 23 mg carbohydrate/g VSS. Fluorescence in situ hybridization (FISH) analysis revealed that the granules were enriched with abundant sulfate-reducing bacteria (SRB) as compared with the seeding sludge. Pyrosequencing analysis of the 16S rRNA gene in the sulfate-reducing granules on day 90 indicated that the microbial community consisted of a diverse SRB genera, namely Desulfobulbus (18.1%), Desulfobacter (13.6%), Desulfomicrobium (5.6%), Desulfosarcina (0.73%) and Desulfovibrio (0.6%), accounting for 38.6% of total operational taxonomic units at genera level, with no methanogens detected. The microbial population and physicochemical properties of the granules well explained the excellent performance of the granular SRUSB reactor. PMID:24200003

  6. Alteration of Nontronite NAU-2 by a Sulfate-Reducing Bacterium

    NASA Astrophysics Data System (ADS)

    Vali, H.; Li, Y.; Sears, S.; Yang, J.; Deng, B.; Zhang, C. L.

    2004-05-01

    Iron-rich clay minerals are abundant in the natural environment. The goal of this study is to understand the mechanisms of enhanced reduction of Fe(III) in Fe-rich clay minerals under sulfate-reducing conditions. In particular, biogenic reduction of the structural Fe(III) and release of other elements in a nontronite sample (NAu-2) are studied using a Desulfovibrio spp. strain G-11 with or without amended sulfate. The microbial production of Fe(II) from NAu-2 was about 10% of total structural Fe(III) (30 mM) when Fe(III) was available as the sole electron acceptor. The production of Fe(II), however, reached 29% of total structural Fe(III) when both Fe(III) and SO4= (50 mM) were concurrently used as the electron acceptors. Abiotic production of Fe(II) from reaction of NAu-2 with Na2S (50 mM), on the other hand, was only ca. 7.5% of total structural Fe(III). The enhanced reduction of structural Fe(III) by G-11, particularly in the presence of sulfate, is directly related to the growth rate and metabolic activities of the bacteria which results in destruction of the structure of the nontronite. Analyses by SEM, TEM, XRD, and EDS revealed significant changes in the structure and composition of NAu-2 during its alteration by bacterial sulfate reduction. G-11 could also derive nutrients from NAu-2 to support its growth in the absence of amended minerals and vitamins. Results of this study suggest that sulfate-reducing bacteria may play a more significant role in cycling of Fe, S, and other elements during alteration of Fe-rich clay minerals and other silicate minerals than previously recognized.

  7. Bioremediation of coal contaminated soil under sulfate-reducing condition.

    PubMed

    Kuwano, Y; Shimizu, Y

    2006-01-01

    The objective of this study was to investigate the biodegradation of coal-derived hydrocarbons, especially high molecular weight (HMW) components, under anaerobic conditions. For this purpose biodegradation experiments were performed, using specifically designed soil column bioreactors. For the experiment, coal-contaminated soil was prepared, which contains high molecular weight hydrocarbons at high concentration (approx. 55.5 mgC g-drysoil(-1)). The experiment was carried out in two different conditions: sulfate reducing (SR) condition (SO4(2-) = 10 mmol l(-1) in the liquid medium) and control condition (SO4(2-)<0.5 mmol l(-1)). Although no degradation was observed under the control condition, the resin fraction decreased to half (from 6,541 to 3,386 mgC g-soil(-1)) under SR condition, with the concomitant increase of two PAHs (phenanthrene and fluoranthene, 9 and 2.5 times, respectively). From these results, we could conclude that high molecular hydrocarbons were biodegradable and transformed to low molecular weight PAHs under the sulfate-reducing condition. Since these PAHs are known to be biologically degraded under aerobic condition, a serial combination of anaerobic (sulfate reducing) and then aerobic bioremediations could be effective and useful for the soil pollution by petroleum and/or coal derived hydrocarbons. PMID:16457179

  8. Uranium reduction and resistance to reoxidation under iron-reducing and sulfate-reducing conditions.

    PubMed

    Boonchayaanant, Benjaporn; Nayak, Dipti; Du, Xin; Criddle, Craig S

    2009-10-01

    Oxidation and mobilization of microbially-generated U(IV) is of great concern for in situ uranium bioremediation. This study investigated the reoxidation of uranium by oxygen and nitrate in a sulfate-reducing enrichment and an iron-reducing enrichment derived from sediment and groundwater from the Field Research Center in Oak Ridge, Tennessee. Both enrichments were capable of reducing U(VI) rapidly. 16S rRNA gene clone libraries of the two enrichments revealed that Desulfovibrio spp. are dominant in the sulfate-reducing enrichment, and Clostridium spp. are dominant in the iron-reducing enrichment. In both the sulfate-reducing enrichment and the iron-reducing enrichment, oxygen reoxidized the previously reduced uranium but to a lesser extent in the iron-reducing enrichment. Moreover, in the iron-reducing enrichment, the reoxidized U(VI) was eventually re-reduced to its previous level. In both, the sulfate-reducing enrichment and the iron-reducing enrichment, uranium reoxidation did not occur in the presence of nitrate. The results indicate that the Clostridium-dominated iron-reducing communities created conditions that were more favorable for uranium stability with respect to reoxidation despite the fact that fewer electron equivalents were added to these systems. The likely reason is that more of the added electrons are present in a form that can reduce oxygen to water and U(VI) back to U(IV). PMID:19651424

  9. Transformation of indole by methanogenic and sulfate-reducing microorganisms isolated from digested sludge

    SciTech Connect

    Shanker, R.; Bollag, J.M. )

    1990-01-01

    In the present study, mineralization of an aromatic N-heterocyclic molecule, indole, by microorganisms present in anaerobically digested sewage sludge was examined. The first step in indole mineralization was the formation of a hydroxylated intermediate, oxindole. The rate of transformation of indole to oxindole and its subsequent disappearance was dependent on the concentration of inoculum and indole and the incubation temperature. Methanogenesis appeared to be the dominant process in the mineralization of indole in 10% digested sludge even in the presence of high concentrations of sulfate. Enrichment of the digested sludge with sulfate as an electron acceptor allowed the isolation of a metabolically stable mixed culture of anaerobic bacteria which transformed indole to oxindole and acetate, and ultimately to methane and carbon dioxide. This mixed culture exhibited a predominance of sulfate-reducers over methanogens with more than 75% of the substrate mineralized to carbon dioxide. The investigation demonstrates that indole can be transformed by both methanogenic and sulfate-reducing microbial populations.

  10. Metabolic niche of a prominent sulfate-reducing human gut bacterium

    PubMed Central

    Rey, Federico E.; Gonzalez, Mark D.; Cheng, Jiye; Ahern, Philip P.; Gordon, Jeffrey I.

    2013-01-01

    Sulfate-reducing bacteria (SRB) colonize the guts of ∼50% of humans. We used genome-wide transposon mutagenesis and insertion-site sequencing, RNA-Seq, plus mass spectrometry to characterize genetic and environmental factors that impact the niche of Desulfovibrio piger, the most common SRB in a surveyed cohort of healthy US adults. Gnotobiotic mice were colonized with an assemblage of sequenced human gut bacterial species with or without D. piger and fed diets with different levels and types of carbohydrates and sulfur sources. Diet was a major determinant of functions expressed by this artificial nine-member community and of the genes that impact D. piger fitness; the latter includes high- and low-affinity systems for using ammonia, a limiting resource for D. piger in mice consuming a polysaccharide-rich diet. Although genes involved in hydrogen consumption and sulfate reduction are necessary for its colonization, varying dietary-free sulfate levels did not significantly alter levels of D. piger, which can obtain sulfate from the host in part via cross-feeding mediated by Bacteroides-encoded sulfatases. Chondroitin sulfate, a common dietary supplement, increased D. piger and H2S levels without compromising gut barrier integrity. A chondroitin sulfate-supplemented diet together with D. piger impacted the assemblage’s substrate utilization preferences, allowing consumption of more reduced carbon sources and increasing the abundance of the H2-producing Actinobacterium, Collinsella aerofaciens. Our findings provide genetic and metabolic details of how this H2-consuming SRB shapes the responses of a microbiota to diet ingredients and a framework for examining how individuals lacking D. piger differ from those who harbor it. PMID:23898195

  11. Bacteriophage Infection of Model Metal Reducing Bacteria

    NASA Astrophysics Data System (ADS)

    Weber, K. A.; Bender, K. S.; Gandhi, K.; Coates, J. D.

    2008-12-01

    Microbially-mediated metal reduction plays a significant role controlling contaminant mobility in aqueous, soil, and sedimentary environments. From among environmentally relevant microorganisms mediating metal reduction, Geobacter spp. have been identified as predominant metal-reducing bacteria under acetate- oxidizing conditions. Due to the significance of these bacteria in environmental systems, it is necessary to understand factors influencing their metabolic physiology. Examination of the annotated finished genome sequence of G. sulfurreducens PCA, G. uraniumreducens Rf4, G. metallireduceans GS-15 as well as a draft genome sequence of Geobacter sp. FRC-32 have identified gene sequences of putative bacteriophage origin. Presence of these sequences indicates that these bacteria are susceptible to phage infection. Polymerase chain reaction (PCR) primer sets designed tested for the presence of 12 of 25 annotated phage-like sequences in G. sulfurreducens PCA and 9 of 17 phage-like sequences in FRC- 32. The following genes were successfully amplified in G. sulfurreducens PCA: prophage type transcription regulator, phage-induced endonuclease, phage tail sheath, 2 phage tail proteins, phage protein D, phage base plate protein, phage-related DNA polymerase, integrase, phage transcriptional regulator, and Cro-like transcription regulator. Nine of the following sequences were present in FRC-32: 4 separate phage- related proteins, phage-related tail component, viron core protein, phage Mu protein, phage base plate, and phage tail sheath. In addition to the bioinformatics evidence, incubation of G. sulfurreducens PCA with 1 μg mL-1 mytomycin C (mutagen stimulating prophage induction) during mid-log phase resulted in significant cell lysis relative to cultures that remained unamended. Cell lysis was concurrent with an increase in viral like particles enumerated using epifluorescent microscopy. In addition, samples collected following this lytic event (~44hours) were

  12. Penetration of Sulfate Reducers through a Porous North Sea Oil Reservoir

    PubMed Central

    Beeder, J.; Nilsen, R. K.; Thorstenson, T.; Torsvik, T.

    1996-01-01

    The presence of mesophilic benzoate-degrading sulfate-reducing bacteria in the water systems of three Norwegian oil platforms was investigated. Strain 4502 was isolated from the injection water system, and specific antibodies were produced against this isolate. It was present in the injection water system during a period of 3 years, but not in the in situ reservoir water. Later it was found in water samples collected from the oil field production system. This showed that strain 4502 had penetrated the reservoir together with the injection water and eventually reached the production well. PMID:16535415

  13. Performance and microbial community dynamics of a sulfate-reducing bioreactor treating coal generated acid mine drainage.

    PubMed

    Burns, Andrew S; Pugh, Charles W; Segid, Yosief T; Behum, Paul T; Lefticariu, Liliana; Bender, Kelly S

    2012-06-01

    The effectiveness of a passive flow sulfate-reducing bioreactor processing acid mine drainage (AMD) generated from an abandoned coal mine in Southern Illinois was evaluated using geochemical and microbial community analysis 10 months post bioreactor construction. The results indicated that the treatment system was successful in both raising the pH of the AMD from 3.09 to 6.56 and in lowering the total iron level by 95.9%. While sulfate levels did decrease by 67.4%, the level post treatment (1153 mg/l) remained above recommended drinking water levels. Stimulation of biological sulfate reduction was indicated by a +2.60‰ increase in δ(34)S content of the remaining sulfate in the water post-treatment. Bacterial community analysis targeting 16S rRNA and dsrAB genes indicated that the pre-treated samples were dominated by bacteria related to iron-oxidizing Betaproteobacteria, while the post-treated water directly from the reactor outflow was dominated by sequences related to sulfur-oxidizing Epsilonproteobacteria and complex carbon degrading Bacteroidetes and Firmicutes phylums. Analysis of the post-treated water, prior to environmental release, revealed that the community shifted back to predominantly iron-oxidizing Betaproteobacteria. DsrA analysis implied limited diversity in the sulfate-reducing population present in both the bioreactor outflow and oxidation pond samples. These results support the use of passive flow bioreactors to lower the acidity, metal, and sulfate levels present in the AMD at the Tab-Simco mine, but suggest modifications of the system are necessary to both stimulate sulfate-reducing bacteria and inhibit sulfur-oxidizing bacteria. PMID:22083105

  14. Wound healing and antibacterial activities of chondroitin sulfate- and acharan sulfate-reduced silver nanoparticles.

    PubMed

    Im, A-Rang; Kim, Jee Young; Kim, Hyun-Seok; Cho, Seonho; Park, Youmie; Kim, Yeong Shik

    2013-10-01

    For topical applications in wound healing, silver nanoparticles (AgNPs) have attracted much attention as antibacterial agents. Herein, we describe a green-synthetic route for the production of biocompatible and crystalline AgNPs using two glycosaminoglycans, chondroitin sulfate (CS) and acharan sulfate (AS), as reducing agents. The synthetic approach avoids the use of toxic chemicals, and the yield of AgNPs formation is found to be 98.1% and 91.1% for the chondroitin sulfate-reduced silver nanoparticles (CS-AgNPs) and the acharan sulfate-reduced silver nanoparticles (AS-AgNPs), respectively. Nanoparticles with mostly spherical and amorphous shapes were observed, with an average diameter of 6.16 ± 2.26 nm for CS-AgNPs and 5.79 ± 3.10 nm for AS-AgNPs. Images of the CS-AgNPs obtained from atomic force microscopy revealed the self-assembled structure of CS was similar to a densely packed woven mat with AgNPs sprinkled on the CS. These nanoparticles were stable under cell culture conditions without any noticeable aggregation. An approximately 128-fold enhancement of the antibacterial activities of the AgNPs was observed against Enterobacter cloacae and Escherichia coli when compared to CS and AS alone. In addition, an in vivo animal model of wound healing activity was tested using mice that were subjected to deep incision wounds. In comparison to the controls, the ointments containing CS-AgNPs and AS-AgNPs stimulated wound closure under histological examination and accelerated the deposition of granulation tissue and collagen in the wound area. The wound healing activity of the ointments containing CS-AgNPs and AS-AgNPs are comparable to that of a commercial formulation of silver sulfadiazine even though the newly prepared ointments contain a lower silver concentration. Therefore, the newly prepared AgNPs demonstrate potential for use as an attractive biocompatible nanocomposite for topical applications in the treatment of wounds. PMID:24008263

  15. Distribution of Thermophilic Marine Sulfate Reducers in North Sea Oil Field Waters and Oil Reservoirs

    PubMed Central

    Nilsen, R. K.; Beeder, J.; Thorstenson, T.; Torsvik, T.

    1996-01-01

    The distribution of thermophilic marine sulfate reducers in produced oil reservoir waters from the Gullfaks oil field in the Norwegian sector of the North Sea was investigated by using enrichment cultures and genus-specific fluorescent antibodies produced against the genera Archaeoglobus, Desulfotomaculum, and Thermodesulforhabdus. The thermophilic marine sulfate reducers in this environment could mainly be classified as species belonging to the genera Archaeoglobus and Thermodesulforhabdus. In addition, some unidentified sulfate reducers were present. Culturable thermophilic Desulfotomaculum strains were not detected. Specific strains of thermophilic sulfate reducers inhabited different parts of the oil reservoir. No correlation between the duration of seawater injection and the numbers of thermophilic sulfate reducers in the produced waters was observed. Neither was there any correlation between the concentration of hydrogen sulfide and the numbers of thermophilic sulfate reducers. The results indicate that thermophilic and hyperthermophilic sulfate reducers are indigenous to North Sea oil field reservoirs and that they belong to a deep subterranean biosphere. PMID:16535321

  16. The genetic basis of energy conservation in the sulfate-reducing bacterium Desulfovibrio alaskensis G20

    DOE PAGESBeta

    Price, Morgan N.; Ray, Jayashree; Wetmore, Kelly M.; Kuehl, Jennifer V.; Bauer, Stefan; Deutschbauer, Adam M.; Arkin, Adam P.

    2014-10-31

    Sulfate-reducing bacteria play major roles in the global carbon and sulfur cycles, but it remains unclear how reducing sulfate yields energy. To determine the genetic basis of energy conservation, we measured the fitness of thousands of pooled mutants of Desulfovibrio alaskensis G20 during growth in 12 different combinations of electron donors and acceptors. We show that ion pumping by the ferredoxin:NADH oxidoreductase Rnf is required whenever substrate-level phosphorylation is not possible. The uncharacterized complex Hdr/flox-1 (Dde_1207:13) is sometimes important alongside Rnf and may perform an electron bifurcation to generate more reduced ferredoxin from NADH to allow further ion pumping. Similarly,more » during the oxidation of malate or fumarate, the electron-bifurcating transhydrogenase NfnAB-2 (Dde_1250:1) is important and may generate reduced ferredoxin to allow additional ion pumping by Rnf. During formate oxidation, the periplasmic [NiFeSe] hydrogenase HysAB is required, which suggests that hydrogen forms in the periplasm, diffuses to the cytoplasm, and is used to reduce ferredoxin, thus providing a substrate for Rnf. We found that during hydrogen utilization, the transmembrane electron transport complex Tmc is important and may move electrons from the periplasm into the cytoplasmic sulfite reduction pathway. Finally, mutants of many other putative electron carriers have no clear phenotype, which suggests that they are not important under our growth conditions, although we cannot rule out genetic redundancy.« less

  17. The genetic basis of energy conservation in the sulfate-reducing bacterium Desulfovibrio alaskensis G20

    SciTech Connect

    Price, Morgan N.; Ray, Jayashree; Wetmore, Kelly M.; Kuehl, Jennifer V.; Bauer, Stefan; Deutschbauer, Adam M.; Arkin, Adam P.

    2014-10-31

    Sulfate-reducing bacteria play major roles in the global carbon and sulfur cycles, but it remains unclear how reducing sulfate yields energy. To determine the genetic basis of energy conservation, we measured the fitness of thousands of pooled mutants of Desulfovibrio alaskensis G20 during growth in 12 different combinations of electron donors and acceptors. We show that ion pumping by the ferredoxin:NADH oxidoreductase Rnf is required whenever substrate-level phosphorylation is not possible. The uncharacterized complex Hdr/flox-1 (Dde_1207:13) is sometimes important alongside Rnf and may perform an electron bifurcation to generate more reduced ferredoxin from NADH to allow further ion pumping. Similarly, during the oxidation of malate or fumarate, the electron-bifurcating transhydrogenase NfnAB-2 (Dde_1250:1) is important and may generate reduced ferredoxin to allow additional ion pumping by Rnf. During formate oxidation, the periplasmic [NiFeSe] hydrogenase HysAB is required, which suggests that hydrogen forms in the periplasm, diffuses to the cytoplasm, and is used to reduce ferredoxin, thus providing a substrate for Rnf. We found that during hydrogen utilization, the transmembrane electron transport complex Tmc is important and may move electrons from the periplasm into the cytoplasmic sulfite reduction pathway. Finally, mutants of many other putative electron carriers have no clear phenotype, which suggests that they are not important under our growth conditions, although we cannot rule out genetic redundancy.

  18. The genetic basis of energy conservation in the sulfate-reducing bacterium Desulfovibrio alaskensis G20

    PubMed Central

    Price, Morgan N.; Ray, Jayashree; Wetmore, Kelly M.; Kuehl, Jennifer V.; Bauer, Stefan; Deutschbauer, Adam M.; Arkin, Adam P.

    2014-01-01

    Sulfate-reducing bacteria play major roles in the global carbon and sulfur cycles, but it remains unclear how reducing sulfate yields energy. To determine the genetic basis of energy conservation, we measured the fitness of thousands of pooled mutants of Desulfovibrio alaskensis G20 during growth in 12 different combinations of electron donors and acceptors. We show that ion pumping by the ferredoxin:NADH oxidoreductase Rnf is required whenever substrate-level phosphorylation is not possible. The uncharacterized complex Hdr/flox-1 (Dde_1207:13) is sometimes important alongside Rnf and may perform an electron bifurcation to generate more reduced ferredoxin from NADH to allow further ion pumping. Similarly, during the oxidation of malate or fumarate, the electron-bifurcating transhydrogenase NfnAB-2 (Dde_1250:1) is important and may generate reduced ferredoxin to allow additional ion pumping by Rnf. During formate oxidation, the periplasmic [NiFeSe] hydrogenase HysAB is required, which suggests that hydrogen forms in the periplasm, diffuses to the cytoplasm, and is used to reduce ferredoxin, thus providing a substrate for Rnf. During hydrogen utilization, the transmembrane electron transport complex Tmc is important and may move electrons from the periplasm into the cytoplasmic sulfite reduction pathway. Finally, mutants of many other putative electron carriers have no clear phenotype, which suggests that they are not important under our growth conditions, although we cannot rule out genetic redundancy. PMID:25400629

  19. Anaerobic Biodegradation of Pristane by Nitrate Reducing Bacteria

    NASA Astrophysics Data System (ADS)

    Dawson, K. S.; Freeman, K. H.; Macalady, J. L.

    2007-12-01

    In recent sediments, microbial biodegradation provides a control on the long-term preservation of organic matter, through the preferential loss of certain biomolecules and the alteration and concentration of other more recalcitrant molecules. Biodegradation of hydrocarbons derived from membrane lipids, has been demonstrated by both aerobic and strictly anaerobic culturing experiments. The isoprenoid pristane, once considered stable under anaerobic conditions, is in fact degraded by a denitrifying microcosm (BREGNARD et al., 1997) and a methanogenic, sulphate-reducing enrichment culture (GROSSI, 2000). We recently demonstrated pristane biodegradation and accompanying loss of nitrate by an activated sludge isolate. The measured nitrate consumption accounts for a 7.1 +/- 0.4 mg loss of pristane, 4.74% of the initial substrate, in 181 days, assuming pristane conversion to CO2. We have characterized the microorganisms active in the biodegradation process, through the creation of a 16S rDNA clone library, as well as fluorescence in situ hybridization (FISH). Experiments are in progress to enrich cultures of sulfate reducing bacteria that utilize pristane as a sole carbon source and to characterize reaction mechanisms in pristane-oxidizing pathways.

  20. Eliminating aluminum toxicity in an acid sulfate soil for rice cultivation using plant growth promoting bacteria.

    PubMed

    Panhwar, Qurban Ali; Naher, Umme Aminun; Radziah, Othman; Shamshuddin, Jusop; Razi, Ismail Mohd

    2015-01-01

    Aluminum toxicity is widely considered as the most important limiting factor for plants growing in acid sulfate soils. A study was conducted in laboratory and in field to ameliorate Al toxicity using plant growth promoting bacteria (PGPB), ground magnesium limestone (GML) and ground basalt. Five-day-old rice seedlings were inoculated by Bacillus sp., Stenotrophomonas maltophila, Burkholderia thailandensis and Burkholderia seminalis and grown for 21 days in Hoagland solution (pH 4.0) at various Al concentrations (0, 50 and 100 μM). Toxicity symptoms in root and leaf were studied using scanning electron microscope. In the field, biofertilizer (PGPB), GML and basalt were applied (4 t·ha-1 each). Results showed that Al severely affected the growth of rice. At high concentrations, the root surface was ruptured, leading to cell collapse; however, no damages were observed in the PGPB inoculated seedlings. After 21 days of inoculation, solution pH increased to >6.0, while the control treatment remained same. Field study showed that the highest rice growth and yield were obtained in the bio-fertilizer and GML treatments. This study showed that Al toxicity was reduced by PGPB via production of organic acids that were able to chelate the Al and the production of polysaccharides that increased solution pH. The release of phytohormones further enhanced rice growth that resulted in yield increase. PMID:25710843

  1. Treatment of acid rock drainage using a sulfate-reducing bioreactor with zero-valent iron.

    PubMed

    Ayala-Parra, Pedro; Sierra-Alvarez, Reyes; Field, James A

    2016-05-01

    This study assessed the bioremediation of acid rock drainage (ARD) in flow-through columns testing zero-valent iron (ZVI) for the first time as the sole exogenous electron donor to drive sulfate-reducing bacteria in permeable reactive barriers. Columns containing ZVI, limestone or a mixture of both materials were inoculated with an anaerobic mixed culture and fed a synthetic ARD containing sulfuric acid and heavy metals (initially copper, and later also cadmium and lead). ZVI significantly enhanced sulfate reduction and the heavy metals were extensively removed (>99.7%). Solid-phase analyses showed that heavy metals were precipitated with biogenic sulfide in the columns packed with ZVI. Excess sulfide was sequestered by iron, preventing the discharge of dissolved sulfide. In the absence of ZVI, heavy metals were also significantly removed (>99.8%) due to precipitation with hydroxide and carbonate ions released from the limestone. Vertical-profiles of heavy metals in the columns packing, at the end of the experiment, demonstrated that the ZVI columns still had excess capacity to remove heavy metals, while the capacity of the limestone control column was approaching saturation. The ZVI provided conditions that enhanced sulfate reduction and generated alkalinity. Collectively, the results demonstrate an innovative passive ARD remediation process using ZVI as sole electron-donor. PMID:26808248

  2. MINE WASTE TECHNOLOGY PROGRAM - SULFATE REDUCING BACTERIA REACTIVE WALL DEMO

    EPA Science Inventory


    Efforts reported in this document focused on the demonstration of a passive technology that could be used for remediation of
    thousands of abandoned mines existing in the Western United States that emanate acid mine drainage (AMD). This passive remedial technology takes ad...

  3. Direct analysis of sulfate reducing bacterial communities in gas hydrate-impacted marine sediments by PCR-DGGE.

    PubMed

    Bagwell, Christopher E; Formolo, Michael; Ye, Qi; Yeager, Chris M; Lyons, Timothy W; Zhang, Chuanlun L

    2009-09-01

    Molecular investigations of the sulfate reducing bacteria that target the dissimilatory sulfite-reductase subunit A gene (dsr A) are plagued by the nonspecific performance of conventional PCR primers. Here we describe the incorporation of the FailSafe PCR System to optimize environmental analysis of dsr A by PCR amplification and denaturing gradient gel electrophoresis. PCR-DGGE analysis of dsr A composition revealed that SRB diversity was greater and more variable throughout the vertical profile of a marine sediment core obtained from a gas hydrate site (GC234) in the Gulf of Mexico than in a sediment core collected from a nearby site devoid of gas hydrates (NBP). Depth profiled dsr B abundance corresponded with sulfate reduction rates at both sites, though measurements were higher at GC234. This study exemplifies the numerical and functional importance of sulfate reducing bacteria in deep-sea sedimentary environments, and incremental methodological advancements, as described herein, will continue to streamline the analysis of sulfate reducer communities in situ. PMID:19322839

  4. Enrichment and characterization of sulfate reducing, naphthalene degrading microorganisms

    NASA Astrophysics Data System (ADS)

    Steffen, Kümmel; Florian-Alexander, Herbst; Márcia, Duarte; Dietmar, Pieper; Jana, Seifert; Bergen Martin, von; Hans-Hermann, Richnow; Carsten, Vogt

    2014-05-01

    Polycyclic aromatic hydrocarbons (PAH) are pollutants of great concern due to their potential toxicity, mutagenicity and carcinogenicity. PAH are widely distributed in the environment by accidental discharges during the transport, use and disposal of petroleum products, and during forest and grass fires. Caused by their hydrophobic nature, PAH basically accumulate in sediments from where they are slowly released into the groundwater. Although generally limited by the low water solubility of PAH, microbial degradation is one of the major mechanisms leading to the complete clean-up of PAH-contaminated sites. Whereas organisms and biochemical pathways responsible for the aerobic breakdown of PAH are well known, anaerobic PAH biodegradation is less understood; only a few anaerobic PAH degrading cultures have been described. We studied the anaerobic PAH degradation in a microcosm approach to enrich anaerobic PAH degraders. Anoxic groundwater and sediment samples were used as inoculum. Groundwater samples were purchased from the erstwhile gas works facility and a former wood impregnation site. In contrast, sources of sediment samples were a former coal refining area and an old fuel depot. Samples were incubated in anoxic mineral salt medium with naphthalene as sole carbon source and sulfate as terminal electron acceptor. Grown cultures were characterized by feeding with 13C-labeled naphthalene, 16S rRNA gene sequencing using an Illumina® approach, and functional proteome analyses. Finally, six enrichment cultures able to degrade naphthalene under anoxic conditions were established. First results point to a dominance of identified sequences affiliated to the freshwater sulfate-reducing strain N47, which is a known anaerobic naphthalene degrader, in four out of the six enrichments. In those enrichments, peptides related to the pathway of anoxic naphthalene degradation in N47 were abundant. Overall the data underlines the importance of Desulfobacteria for natural

  5. Linking Microbial Ecology to Geochemistry in Sulfate Reducing Systems

    NASA Astrophysics Data System (ADS)

    Drennan, D. M.; Lee, I.; Landkamer, L.; Almstrand, R.; Figueroa, L. A.; Sharp, J. H.

    2013-12-01

    Sulfate reducing bioreactors (SRBRs) can serve as passive treatment systems for mining influenced waters (MIW). An enhanced understanding of the biogeochemistry and efficacy of SRBRs can be achieved by combining molecular biological and geochemical techniques in both field and column settings. To this end, a spatial and temporal sequence of eight pilot-scale columns were analyzed employing a multidisciplinary approach using ICP-AES, next-generation sequencing, and SEM-EDX to explore the effects of variable substrate on community structure and performance (measured by Zn removal). All pilot scale reactors contained 30% limestone by mass, 7 of the 8 had variable amounts of woodchips, sawdust, and alfalfa hay, and an 8th column where the only carbon source was walnut shells. High throughput sequencing of DNA extracted from liquid in pilot-scale columns reveals, similarly to an analogous field system in Arizona, a dominance of Proteobacteria. However, after the first pore volume, performance differences between substrate permutations emerged, where columns containing exclusively walnut shells or sawdust exhibited a more effective startup and metal removal than did columns containing exclusively woodchips or alfalfa hay. SEM-EDX analysis revealed the initial formation of gypsum (CaSO4) precipitates regardless of substrate. Zn was observed in the presence of Ca, S, and O in some column samples, suggesting there was co-precipitation of Zn and CaSO4. This is congruent with micro-XAS analysis of field data suggesting iron sulfides were co-precipitating with gypsum. A SEM-EDX analysis from a subsequent sampling event (8 months into operation) indicated that precipitation may be shifting to ZnS and ZnCO3. Biplots employing Canonical Correspondence Analysis (CCA) describe how diversity scales with performance and substrate selection, and how community shifts may result in differential performance and precipitation in response to selective pressure of bioreactor material on

  6. Microbial community analysis of two field-scale sulfate-reducing bioreactors treating mine drainage.

    PubMed

    Hiibel, Sage R; Pereyra, Luciana P; Inman, Laura Y; Tischer, April; Reisman, David J; Reardon, Kenneth F; Pruden, Amy

    2008-08-01

    The microbial communities of two field-scale pilot sulfate-reducing bioreactors treating acid mine drainage (AMD), Luttrell and Peerless Jenny King (PJK), were compared using biomolecular tools and multivariate statistical analyses. The two bioreactors were well suited for this study because their geographic locations and substrate compositions were similar while the characteristics of influent AMD, configuration and degree of exposure to oxygen were distinct. The two bioreactor communities were found to be functionally similar, including cellulose degraders, fermenters and sulfate-reducing bacteria (SRB). Significant differences were found between the two bioreactors in phylogenetic comparisons of cloned 16S rRNA genes and adenosine 5'-phosphosulfate reductase (apsA) genes. The apsA gene clones from the Luttrell bioreactor were dominated by uncultured SRB most closely related to Desulfovibrio spp., while those of the PJK bioreactor were dominated by Thiobacillus spp. The fraction of the SRB genus Desulfovibrio was also higher at Luttrell than at PJK as determined by quantitative real-time polymerase chain reaction analysis. Oxygen exposure at PJK is hypothesized to be the primary cause of these differences. This study is the first rigorous phylogenetic investigation of field-scale bioreactors treating AMD and the first reported application of multivariate statistical analysis of remediation system microbial communities applying UniFrac software. PMID:18430021

  7. Abiotic transformation of dinitrophenols under sulfate-reducing conditions

    SciTech Connect

    Gui, L.; Bouwer, E.J.

    1996-10-01

    Dinitrophenols are hazardous chemicals commonly detected in the environment. Little is known about their fate under sulfate-reducing conditions (SRC) where H{sub 2}S level is elevated due to microbial activity. Dinitrophenols are susceptible to both biotic and abiotic transformation under SRC. The objectives of this research are to investigate dinitrophenol transformation using hydrogen sulfide as a reductant, and to determine factors that affect the abiotic transformation kinetics under SRC. Dinitrophenols studied were 2,4-dinitrophenol (DNP), 4,6-dinitro-o-cresol (DNOC), and 2-sec-butyl-4,6-dinitrophenol (dinoseb). All three dinitrophenols were transformed through an ortho-nitroreduction pathway. In the presence of H{sub 2}S as the bulk reductant and a small amount of trace metals (10{sup -6} to 10{sup -7} M), pseudo-first-order kinetics was observed. Addition of yeast extract (YE, 0.02%) enhanced dinoseb transformation rate significantly. An increase in HS concentration resulted in Michaelis-Menton type kinetics for dinoseb in the presence of trace metals and YE, suggesting that trace metals and YE functioned as electron mediators.

  8. Visualization of Mercury Methylating Pure-Culture Sulfate-Reducing Biofilms

    NASA Astrophysics Data System (ADS)

    Lin, C.; Reyes, C.; Mendez, C.; Jay, J. A.

    2005-12-01

    Methylmercury is a potent neurotoxin that can accumulate in food chains posing a serious ecological problem in certain aquatic systems. Relatively less toxic inorganic mercury (Hg) is converted to methylmercury (CH3Hg+) by bacteria, and it has been shown that sulfate reducing bacteria (SRB) are the major mediators of this process in many aquatic systems. To date, all laboratory studies on bacterial mercury methylation by SRB have been conducted using planktonic, free floating, bacterial cultures, yet bacteria exist mostly as attached communities or biofilms in the environment. We hypothesized that biofilms composed of different SRB would differ in their ability to bind and methylate mercury compared to planktonic cultures. To test our hypothesis ten SRB isolates capable of producing biofilms in the laboratory were enriched from a marine sediment. We identified the isolates by 16S rDNA sequence analysis, compared pure-culture biofilm structure using fluorescent in situ hybridization (FISH) and confocal microscopy, and measured mercury methylation in biofilms of these SRB.

  9. Complete genome sequence of the sulfate-reducing firmicute Desulfotomaculum ruminis type strain (DLT)

    PubMed Central

    Spring, Stefan; Visser, Michael; Lu, Megan; Copeland, Alex; Lapidus, Alla; Lucas, Susan; Cheng, Jan-Fang; Han, Cliff; Tapia, Roxanne; Goodwin, Lynne A.; Pitluck, Sam; Ivanova, Natalia; Land, Miriam; Hauser, Loren; Larimer, Frank; Rohde, Manfred; Göker, Markus; Detter, John C.; Kyrpides, Nikos C.; Woyke, Tanja; Schaap, Peter J.; Plugge, Caroline M.; Muyzer, Gerard; Kuever, Jan; Pereira, Inês A. C.; Parshina, Sofiya N.; Bernier-Latmani, Rizlan; Stams, Alfons J.M.; Klenk, Hans-Peter

    2012-01-01

    Desulfotomaculum ruminis Campbell and Postgate 1965 is a member of the large genus Desulfotomaculum which contains 30 species and is contained in the family Peptococcaceae. This species is of interest because it represents one of the few sulfate-reducing bacteria that have been isolated from the rumen. Here we describe the features of D. ruminis together with the complete genome sequence and annotation. The 3,969,014 bp long chromosome with a total of 3,901 protein-coding and 85 RNA genes is the second completed genome sequence of a type strain of the genus Desulfotomaculum to be published, and was sequenced as part of the DOE Joint Genome Institute Community Sequencing Program 2009. PMID:23408247

  10. Comparison of sulfate-reducing and conventional Anammox upflow anaerobic sludge blanket reactors.

    PubMed

    Rikmann, Ergo; Zekker, Ivar; Tomingas, Martin; Vabamäe, Priit; Kroon, Kristel; Saluste, Alar; Tenno, Taavo; Menert, Anne; Loorits, Liis; Rubin, Sergio S C dC; Tenno, Toomas

    2014-10-01

    Autotrophic NH4(+) removal has been extensively researched, but few studies have investigated alternative electron acceptors (for example, SO4(2-)) in NH4(+) oxidation. In this study, sulfate-reducing anaerobic ammonium oxidation (SRAO) and conventional Anammox were started up in upflow anaerobic sludge blanket reactors (UASBRs) at 36 (±0.5)°C and 20 (±0.5)°C respectively, using reject water as a source of NH4(+). SO4(2-) or NO2(-), respectively, were applied as electron acceptors. It was assumed that higher temperature could promote the SRAO, partly compensating its thermodynamic disadvantage comparing with the conventional Anammox to achieve comparable total nitrogen (TN) removal rate. Average volumetric NH4(+)-N removal rate in the sulfate-reducing UASBR1 was however 5-6 times less (0.03 kg-N/(m(3) day)) than in the UASBR2 performing conventional nitrite-dependent autotrophic nitrogen removal (0.17 kg-N/(m(3) day)). However, the stoichiometric ratio of NH4(+) removal in UASBR1 was significantly higher than could be expected from the extent of SO4(2-) reduction, possibly due to interactions between the N- and S-compounds and organic matter of the reject water. Injections of N2H4 and NH2OH accelerated the SRAO. Similar effect was observed in batch tests with anthraquinone-2,6-disulfonate (AQDS). For detection of key microorganisms PCR-DGGE was used. From both UASBRs, uncultured bacterium clone ATB-KS-1929 belonging to the order Verrucomicrobiales, Anammox bacteria (uncultured Planctomycete clone Pla_PO55-9) and aerobic ammonium-oxidizing bacteria (uncultured sludge bacterium clone ASB08 "Nitrosomonas") were detected. Nevertheless the SRAO process was shown to be less effective for the treatment of reject water, compared to the conventional Anammox. PMID:24863179

  11. Impact of Organic Carbon Electron Donors on Microbial Community Development under Iron- and Sulfate-Reducing Conditions.

    PubMed

    Kwon, Man Jae; O'Loughlin, Edward J; Boyanov, Maxim I; Brulc, Jennifer M; Johnston, Eric R; Kemner, Kenneth M; Antonopoulos, Dionysios A

    2016-01-01

    Although iron- and sulfate-reducing bacteria in subsurface environments have crucial roles in biogeochemical cycling of C, Fe, and S, how specific electron donors impact the compositional structure and activity of native iron- and/or sulfate-reducing communities is largely unknown. To understand this better, we created bicarbonate-buffered batch systems in duplicate with three different electron donors (acetate, lactate, or glucose) paired with ferrihydrite and sulfate as the electron acceptors and inoculated them with subsurface sediment as the microbial inoculum. Sulfate and ferrihydrite reduction occurred simultaneously and were faster with lactate than with acetate. 16S rRNA-based sequence analysis of the communities over time revealed that Desulfotomaculum was the major driver for sulfate reduction coupled with propionate oxidation in lactate-amended incubations. The reduction of sulfate resulted in sulfide production and subsequent abiotic reduction of ferrihydrite. In contrast, glucose promoted faster reduction of ferrihydrite, but without reduction of sulfate. Interestingly, the glucose-amended incubations led to two different biogeochemical trajectories among replicate bottles that resulted in distinct coloration (white and brown). The two outcomes in geochemical evolution might be due to the stochastic evolution of the microbial communities or subtle differences in the initial composition of the fermenting microbial community and its development via the use of different glucose fermentation pathways available within the community. Synchrotron-based x-ray analysis indicated that siderite and amorphous Fe(II) were formed in the replicate bottles with glucose, while ferrous sulfide and vivianite were formed with lactate or acetate. These data sets reveal that use of different C utilization pathways projects significant changes in microbial community composition over time that uniquely impact both the geochemistry and mineralogy of subsurface environments

  12. Impact of Organic Carbon Electron Donors on Microbial Community Development under Iron- and Sulfate-Reducing Conditions

    PubMed Central

    Kwon, Man Jae; O’Loughlin, Edward J.; Boyanov, Maxim I.; Brulc, Jennifer M.; Johnston, Eric R.; Kemner, Kenneth M.; Antonopoulos, Dionysios A.

    2016-01-01

    Although iron- and sulfate-reducing bacteria in subsurface environments have crucial roles in biogeochemical cycling of C, Fe, and S, how specific electron donors impact the compositional structure and activity of native iron- and/or sulfate-reducing communities is largely unknown. To understand this better, we created bicarbonate-buffered batch systems in duplicate with three different electron donors (acetate, lactate, or glucose) paired with ferrihydrite and sulfate as the electron acceptors and inoculated them with subsurface sediment as the microbial inoculum. Sulfate and ferrihydrite reduction occurred simultaneously and were faster with lactate than with acetate. 16S rRNA-based sequence analysis of the communities over time revealed that Desulfotomaculum was the major driver for sulfate reduction coupled with propionate oxidation in lactate-amended incubations. The reduction of sulfate resulted in sulfide production and subsequent abiotic reduction of ferrihydrite. In contrast, glucose promoted faster reduction of ferrihydrite, but without reduction of sulfate. Interestingly, the glucose-amended incubations led to two different biogeochemical trajectories among replicate bottles that resulted in distinct coloration (white and brown). The two outcomes in geochemical evolution might be due to the stochastic evolution of the microbial communities or subtle differences in the initial composition of the fermenting microbial community and its development via the use of different glucose fermentation pathways available within the community. Synchrotron-based x-ray analysis indicated that siderite and amorphous Fe(II) were formed in the replicate bottles with glucose, while ferrous sulfide and vivianite were formed with lactate or acetate. These data sets reveal that use of different C utilization pathways projects significant changes in microbial community composition over time that uniquely impact both the geochemistry and mineralogy of subsurface environments

  13. Uranium removal by sulfate reducing biofilms in the presence of carbonates

    SciTech Connect

    Marsili, E.; Beyenal, Haluk; Di Palma, L.; Merli, C.; Dohnalkova, Alice; Amonette, James E.; Lewandowski, Zbigniew

    2005-12-01

    Hexavalent uranium [U(VI)] was immobilized in biofilms composed of the sulfate reducing bacteria (SRB), Desulfovibrio desulfuricans G20. The biofilms were grown in two flat-plate, continuous-flow reactors using lactate as the electron donor and sulfate as the electron acceptor. The growth medium contained uranium U(VI) and the pH was maintained constant using bicarbonate buffer. The reactors were operated for 5 months, and during that time biofilm activity and uranium removal were evaluated. The efficiency of uranium removal strongly depended on the concentration of uranium in the influent, and was estimated to be 30.4% in the reactor supplied with 3 mg/L of U(VI) and 73.9% in the reactor supplied with 30 mg/L of U(VI). TEM and SAED analysis showed that uranium in both reactors accumulated mostly on microbial cell membranes and in the periplasmic space. The deposits had amorphous or poor nanocrystalline structures.

  14. Magnetic bacteria against MIC

    SciTech Connect

    Javaherdashti, R.

    1997-12-01

    In this article, it is suggested to use the sensitivity of magnetotactic bacteria to changes of magnetic field direction and the natural ability of this bacteria in rapid growth during relatively short time intervals against corrosion-enhancing bacteria and especially sulfate-reducing bacteria. If colonies of sulfate-reducing bacteria could be packed among magnetotactic bacteria, then, by applying sufficiently powerful magnetic field (about 0.5 gauss), all of these bacteria (magnetic and non-magnetic) will be oriented towards an Anti-bacteria agent (oxygen or biocide). So, Microbiologically-Influenced Corrosion in the system would be controlled to a large extent.

  15. Complete genome sequence of the acetate-degrading sulfate reducer Desulfobacca acetoxidans type strain (ASRB2T)

    SciTech Connect

    Goker, Markus; Teshima, Hazuki; Lapidus, Alla L.; Nolan, Matt; Lucas, Susan; Hammon, Nancy; Deshpande, Shweta; Cheng, Jan-Fang; Tapia, Roxanne; Han, Cliff; Goodwin, Lynne A.; Pitluck, Sam; Huntemann, Marcel; Liolios, Konstantinos; Ivanova, N; Pagani, Ioanna; Mavromatis, K; Ovchinnikova, Galina; Pati, Amrita; Chen, Amy; Palaniappan, Krishna; Land, Miriam L; Hauser, Loren John; Brambilla, Evelyne-Marie; Rohde, Manfred; Spring, Stefan; Detter, J. Chris; Woyke, Tanja; Bristow, James; Eisen, Jonathan; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C; Klenk, Hans-Peter

    2011-01-01

    Desulfobacca acetoxidans Elferink et al. 1999 is the type species of the genus Desulfobacca, which belongs to the family Syntrophaceae in the class Deltaproteobacteria. The species was first observed in a study on the competition of sulfate-reducers and acetoclastic methanogens for acetate in sludge. D. acetoxidans is considered to be the most abundant acetate-degrading sulfate reducer in sludge. It is of interest due to its isolated phylogenetic location in the 16S rRNA-based tree of life. This is the second completed genome sequence of a member of the family Syntrophaceae to be published and only the third genome sequence from a member of the order Syntrophobacterales. The 3,282,536 bp long genome with its 2,969 protein-coding and 54 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

  16. Use of a passive bioreactor to reduce water-borne plant pathogens, nitrate, and sulfate in greenhouse effluent.

    PubMed

    Gruyer, Nicolas; Dorais, Martine; Alsanius, Beatrix W; Zagury, Gérald J

    2013-01-01

    The goal of this study was to evaluate the use of passive bioreactors to reduce water-borne plant pathogens (Pythium ultimum and Fusarium oxysporum) and nutrient load (NO(-) 3 and SO(2-) 4) in greenhouse effluent. Sterilized and unsterilized passive bioreactors filled with a reactive mixture of organic carbon material were used in three replicates. After a startup period of 2 (sterilized) or 5 (unsterilized) weeks, the bioreactor units received for 14 weeks a reconstituted commercial greenhouse effluent composed of 500 mg L(-1) SO(2-) 4 and 300 mg L(-1) NO(-) 3 and were inoculated three times with P. ultimum and F. oxysporum (10(6) CFU mL(-1)). Efficacy in removing water-borne plant pathogens and nitrate reached 99.9% for both the sterilized and unsterilized bioreactors. However, efficacy in reducing the SO(2-) 4 load sharply decreased from 89% to 29% after 2 weeks of NO(-) 3-supply treatment for the unsterilized bioreactors. Although SO(2-) 4 removal efficacy for the sterilized bioreactors did not recover after 4 weeks of NO(-) 3-supply treatment, the unsterilized bioreactor nearly reached a similar level of SO(2-) 4 removal after 4 weeks of NO(-) 3-supply treatment compared with affluent loaded only with SO(2-) 4, where no competition for the carbohydrate source occurred between the denitrification process and sulfate-reducing bacteria activity. Performance differences between the sterilized and unsterilized bioreactors clearly show the predominant importance of sulfate-reducing bacteria. Consequently, when sulfate-reducing bacteria reach their optimal activity, passive bioreactors may constitute a cheap, low-maintenance method of treating greenhouse effluent to recycle wastewater and eliminate nutrient runoff, which has important environmental impacts. PMID:23947714

  17. An Exploratory Study on the Pathways of Cr (VI) Reduction in Sulfate-reducing Up-flow Anaerobic Sludge Bed (UASB) Reactor

    PubMed Central

    Qian, Jin; Wei, Li; Liu, Rulong; Jiang, Feng; Hao, Xiaodi; Chen, Guang-Hao

    2016-01-01

    Electroplating wastewater contains both Cr (VI) and sulfate. So Cr (VI) removal under sulfate-rich condition is quite complicated. This study mainly investigates the pathways for Cr (VI) removal under biological sulfate-reducing condition in the up-flow anaerobic sludge bed (UASB) reactor. Two potential pathways are found for the removal of Cr (VI). The first one is the sulfidogenesis-induced Cr (VI) reduction pathway (for 90% Cr (VI) removal), in which Cr (VI) is reduced by sulfide generated from biological reduction of sulfate. The second one leads to direct reduction of Cr (VI) which is utilized by bacteria as the electron acceptor (for 10% Cr (VI) removal). Batch test results confirmed that sulfide was oxidized to elemental sulfur instead of sulfate during Cr (VI) reduction. The produced extracellular polymeric substances (EPS) provided protection to the microbes, resulting in effective removal of Cr (VI). Sulfate-reducing bacteria (SRB) genera accounted for 11.1% of the total bacterial community; thus they could be the major organisms mediating the sulfidogenesis-induced reduction of Cr (VI). In addition, chromate-utilizing genera (e.g. Microbacterium) were also detected, which were possibly responsible for the direct reduction of Cr (VI) using organics as the electron donor and Cr (VI) as the electron acceptor. PMID:27021522

  18. An Exploratory Study on the Pathways of Cr (VI) Reduction in Sulfate-reducing Up-flow Anaerobic Sludge Bed (UASB) Reactor.

    PubMed

    Qian, Jin; Wei, Li; Liu, Rulong; Jiang, Feng; Hao, Xiaodi; Chen, Guang-Hao

    2016-01-01

    Electroplating wastewater contains both Cr (VI) and sulfate. So Cr (VI) removal under sulfate-rich condition is quite complicated. This study mainly investigates the pathways for Cr (VI) removal under biological sulfate-reducing condition in the up-flow anaerobic sludge bed (UASB) reactor. Two potential pathways are found for the removal of Cr (VI). The first one is the sulfidogenesis-induced Cr (VI) reduction pathway (for 90% Cr (VI) removal), in which Cr (VI) is reduced by sulfide generated from biological reduction of sulfate. The second one leads to direct reduction of Cr (VI) which is utilized by bacteria as the electron acceptor (for 10% Cr (VI) removal). Batch test results confirmed that sulfide was oxidized to elemental sulfur instead of sulfate during Cr (VI) reduction. The produced extracellular polymeric substances (EPS) provided protection to the microbes, resulting in effective removal of Cr (VI). Sulfate-reducing bacteria (SRB) genera accounted for 11.1% of the total bacterial community; thus they could be the major organisms mediating the sulfidogenesis-induced reduction of Cr (VI). In addition, chromate-utilizing genera (e.g. Microbacterium) were also detected, which were possibly responsible for the direct reduction of Cr (VI) using organics as the electron donor and Cr (VI) as the electron acceptor. PMID:27021522

  19. Identification of key components in the energy metabolism of the hyperthermophilic sulfate-reducing archaeon Archaeoglobus fulgidus by transcriptome analyses

    PubMed Central

    Hocking, William P.; Stokke, Runar; Roalkvam, Irene; Steen, Ida H.

    2014-01-01

    Energy conservation via the pathway of dissimilatory sulfate reduction is present in a diverse group of prokaryotes, but is most comprehensively studied in Deltaproteobacteria. In this study, whole-genome microarray analyses were used to provide a model of the energy metabolism of the sulfate-reducing archaeon Archaeoglobus fulgidus, based on comparative analysis of litoautotrophic growth with H2/CO2 and thiosulfate, and heterotrophic growth on lactate with sulfate or thiosulfate. Only 72 genes were expressed differentially between the cultures utilizing sulfate or thiosulfate, whereas 269 genes were affected by a shift in energy source. We identified co-located gene cluster encoding putative lactate dehydrogenases (LDHs; lldD, dld, lldEFG), also present in sulfate-reducing bacteria. These enzymes may take part in energy conservation in A. fulgidus by specifically linking lactate oxidation with APS reduction via the Qmo complex. High transcriptional levels of Fqo confirm an important role of F420H2, as well as a menaquinone-mediated electron transport chain, during heterotrophic growth. A putative periplasmic thiosulfate reductase was identified by specific up-regulation. Also, putative genes for transport of sulfate and sulfite are discussed. We present a model for hydrogen metabolism, based on the probable bifurcation reaction of the Mvh:Hdl hydrogenase, which may inhibit the utilization of Fdred for energy conservation. Energy conservation is probably facilitated via menaquinone to multiple membrane-bound heterodisulfide reductase (Hdr) complexes and the DsrC protein—linking periplasmic hydrogenase (Vht) to the cytoplasmic reduction of sulfite. The ambiguous roles of genes corresponding to fatty acid metabolism induced during growth with H2 are discussed. Putative co-assimilation of organic acids is favored over a homologous secondary carbon fixation pathway, although both mechanisms may contribute to conserve the amount of Fdred needed during autotrophic

  20. Draft Genome Sequence of the Obligately Alkaliphilic Sulfate-Reducing Bacterium Desulfonatronum thiodismutans Strain MLF1

    PubMed Central

    Trubitsyn, Denis; Geurink, Corey; Pikuta, Elena; Lefèvre, Christopher T.; McShan, W. Michael; Gillaspy, Allison F.

    2014-01-01

    Desulfonatronum thiodismutans strain MLF1, an alkaliphilic bacterium capable of sulfate reduction, was isolated from Mono Lake, California. Here we report the 3.92-Mb draft genome sequence comprising 34 contigs and some results of its automated annotation. These data will improve our knowledge of mechanisms by which bacteria withstand extreme environments. PMID:25081260

  1. U(VI) Reduction in Sulfate-Reducing Subsurface Sediments Amended with Ethanol or Acetate

    PubMed Central

    Converse, Brandon J.; Wu, Tao; Findlay, Robert H.

    2013-01-01

    An experiment was conducted with subsurface sediments from Oak Ridge National Laboratory to determine the potential for reduction of U(VI) under sulfate-reducing conditions with either ethanol or acetate as the electron donor. The results showed extensive U(VI) reduction in sediments supplied with either electron donor, where geochemical and microbiological analyses demonstrated active sulfate reduction. PMID:23624470

  2. Disruption of adenosine-5'-phosphosulfate kinase in Arabidopsis reduces levels of sulfated secondary metabolites.

    PubMed

    Mugford, Sarah G; Yoshimoto, Naoko; Reichelt, Michael; Wirtz, Markus; Hill, Lionel; Mugford, Sam T; Nakazato, Yoshimi; Noji, Masaaki; Takahashi, Hideki; Kramell, Robert; Gigolashvili, Tamara; Flügge, Ulf-Ingo; Wasternack, Claus; Gershenzon, Jonathan; Hell, Rüdiger; Saito, Kazuki; Kopriva, Stanislav

    2009-03-01

    Plants can metabolize sulfate by two pathways, which branch at the level of adenosine 5'-phosphosulfate (APS). APS can be reduced to sulfide and incorporated into Cys in the primary sulfate assimilation pathway or phosphorylated by APS kinase to 3'-phosphoadenosine 5'-phosphosulfate, which is the activated sulfate form for sulfation reactions. To assess to what extent APS kinase regulates accumulation of sulfated compounds, we analyzed the corresponding gene family in Arabidopsis thaliana. Analysis of T-DNA insertion knockout lines for each of the four isoforms did not reveal any phenotypical alterations. However, when all six combinations of double mutants were compared, the apk1 apk2 plants were significantly smaller than wild-type plants. The levels of glucosinolates, a major class of sulfated secondary metabolites, and the sulfated 12-hydroxyjasmonate were reduced approximately fivefold in apk1 apk2 plants. Although auxin levels were increased in the apk1 apk2 mutants, as is the case for most plants with compromised glucosinolate synthesis, typical high auxin phenotypes were not observed. The reduction in glucosinolates resulted in increased transcript levels for genes involved in glucosinolate biosynthesis and accumulation of desulfated precursors. It also led to great alterations in sulfur metabolism: the levels of sulfate and thiols increased in the apk1 apk2 plants. The data indicate that the APK1 and APK2 isoforms of APS kinase play a major role in the synthesis of secondary sulfated metabolites and are required for normal growth rates. PMID:19304933

  3. Identification of the dominant sulfate-reducing bacterial partner of anaerobic methanotrophs of the ANME-2 clade.

    PubMed

    Schreiber, Lars; Holler, Thomas; Knittel, Katrin; Meyerdierks, Anke; Amann, Rudolf

    2010-08-01

    The anaerobic oxidation of methane (AOM) with sulfate as terminal electron acceptor is mediated by consortia of methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB). Whereas three clades of ANME have been repeatedly studied with respect to phylogeny, key genes and genomic capabilities, little is known about their sulfate-reducing partner. In order to identify the partner of anaerobic methanotrophs of the ANME-2 clade, bacterial 16S rRNA gene libraries were constructed from cultures highly enriched for ANME-2a and ANME-2c in consortia with Deltaproteobacteria of the Desulfosarcina/Desulfococcus group (DSS). Phylogenetic analysis of those and publicly available sequences from AOM sites supported the hypothesis by Knittel and colleagues that the DSS partner belongs to the diverse SEEP-SRB1 cluster. Six subclusters of SEEP-SRB1, SEEP-SRB1a to SEEP-SRB1f, were proposed and specific oligonucleotide probes were designed. Using fluorescence in situ hybridization on samples from six different AOM sites, SEEP-SRB1a was identified as sulfate-reducing partner in up to 95% of total ANME-2 consortia. SEEP-SRB1a cells exhibited a rod-shaped, vibrioid, or coccoid morphology and were found to be associated with subgroups ANME-2a and ANME-2c. Moreover, SEEP-SRB1a was also detected in 8% to 23% of ANME-3 consortia in Haakon Mosby Mud Volcano sediments, previously described to be predominantly associated with SRB of the Desulfobulbus group. SEEP-SRB1a contributed to only 0.3% to 0.7% of all single cells in almost all samples indicating that these bacteria are highly adapted to a symbiotic relationship with ANME-2. PMID:21966923

  4. Biogeochemistry of a Field-Scale Sulfate Reducing Bioreactor Treating Mining Influenced Water

    NASA Astrophysics Data System (ADS)

    Drennan, D.; Lee, I.; Landkamer, L.; Figueroa, L. A.; Webb, S.; Sharp, J. O.

    2012-12-01

    Acidity, metal release, and toxicity may be environmental health concerns in areas influenced by mining. Mining influenced waters (MIW) can be remediated through the establishment of Sulfate Reducing Bioreactors (SRBRs) as part of engineered passive treatment systems. The objective of our research is an enhanced understanding of the biogeochemistry in SRBRs by combining molecular biological and geochemical techniques. Bioreactor reactive substrate, settling pond water, and effluent (from the SRBR) were collected from a field scale SRBR in Arizona, which has been in operation for approximately 3 years. Schematically, the water passes through the SRBR; combines with flow that bypasses the SRBR into the and goes into the mixing pond, and finally is released as effluent to aerobic polishing cells. High throughput sequencing of extracted DNA revealed that Proteobacteria dominated the reactive substrate (61%), settling pond (93%), and effluent (50%), with the next most abundant phylum in all samples (excluding uncultured organisms) being Bacteriodes (1-17%). However, at the superclass level, the three samples were more variable. Gammaproteobacteria dominated the reactive substrate (35%), Betaproteobacteria in the settling pond (63%) and finally the effluent was dominated by Epsilonproteobacteria (Helicobacteraceae) (43%). Diversity was most pronounced in association with the reactor matrix, and least diverse in the settling pond. Putative functional analysis revealed a modest presence of sulfate/sulfur reducing bacteria (SRB) (>5%) in both the matrix and settling pond but a much higher abundance (43%) of sulfur reducing bacteria in the effluent. Interestingly this effluent population was composed entirely of the family Helicobacteraceae (sulfur reduction II via polysulfide pathway). Other putative functions of interest include metal reduction in the matrix (3%) and effluent (3%), as well as polysaccharide degradation, which was largely abundant in all samples (21

  5. The effect of inoculum on the performance of sulfate-reducing columns treating heavy metal contaminated water.

    PubMed

    Pruden, A; Messner, N; Pereyra, L; Hanson, R E; Hiibel, S R; Reardon, K F

    2007-02-01

    Sulfate-reducing permeable reactive zones (SR-PRZs) are a passive means of immobilizing metals and neutralizing the pH of mine drainage through microbially mediated reactions. In this bench-scale study, the influence of inoculum on the performance of columns simulating SR-PRZs was investigated using chemical and biomolecular analyses. Columns inoculated from two sources (bovine dairy manure (DM) and a previous sulfate-reducing column (SRC)) and uninoculated columns (U) were fed a simulated mine drainage and compared on the basis of pH neutralization and removal of cadmium, zinc, iron, and sulfate. Cadmium, zinc, and sulfate removal was significantly higher in SRC columns than in the DM and U columns, while there was no significant difference between the DM and U columns. Denaturing gradient gel electrophoresis (DGGE) analysis revealed differences in the microbial community composition among columns with different inocula, and indicated that the microbial community in the SRC columns was the first to reach a pseudo-steady state. In the SRC columns, a higher proportion of the DGGE band DNA sequences were related to microorganisms that carry out cellulose degradation, the rate-limiting step in SR-PRZ energy flow, than was the case in the other columns. The proportion of sulfate-reducing bacteria of the genus Desulfobacterium was monitored using real-time quantitative PCR and was observed to be consistently higher in the SRC columns. The results of this study suggest that the inoculum plays an important role in SR-PRZ performance. This is the first report providing a detailed analysis of the effect of different microbial inocula on the remediation of acid mine drainage. PMID:17222885

  6. Molecular assessment of the sensitivity of sulfate-reducing microbial communities remediating mine drainage to aerobic stress.

    PubMed

    Lefèvre, Emilie; Pereyra, Luciana P; Hiibel, Sage R; Perrault, Elizabeth M; De Long, Susan K; Reardon, Kenneth F; Pruden, Amy

    2013-09-15

    Sulfate-reducing permeable reactive zones (SR-PRZs) are microbially-driven anaerobic systems designed for the removal of heavy metals and sulfate in mine drainage. Environmental perturbations, such as oxygen exposure, may adversely affect system stability and long-term performance. The objective of this study was to examine the effect of two successive aerobic stress events on the performance and microbial community composition of duplicate laboratory-scale lignocellulosic SR-PRZs operated using the following microbial community management strategies: biostimulation with ethanol or carboxymethylcellulose; bioaugmentation with sulfate-reducing or cellulose-degrading enrichments; inoculation with dairy manure only; and no inoculation. A functional gene-based approach employing terminal restriction fragment length polymorphism and quantitative polymerase chain reaction targeting genes of sulfate-reducing (dsrA), cellulose-degrading (cel5, cel48), fermentative (hydA), and methanogenic (mcrA) microbes was applied. In terms of performance (i.e., sulfate removal), biostimulation with ethanol was the only strategy that clearly had an effect (positive) following exposure to oxygen. In terms of microbial community composition, significant shifts were observed over the course of the experiment. Results suggest that exposure to oxygen more strongly influenced microbial community shifts than the different microbial community management strategies. Sensitivity to oxygen exposure varied among different populations and was particularly pronounced for fermentative bacteria. Although the community structure remained altered after exposure, system performance recovered, indicating that SR-PRZ microbial communities were functionally redundant. Results suggest that pre-exposure to oxygen might be a more effective strategy to improve the resilience of SR-PRZ microbial communities relative to bioaugmentation or biostimulation. PMID:23863381

  7. Genome sequence of the thermophilic sulfate-reducing ocean bacterium Thermodesulfatator indicus type strain (CIR29812T)

    SciTech Connect

    Anderson, Iain; Saunders, Elizabeth H; Lapidus, Alla L.; Nolan, Matt; Lucas, Susan; Tice, Hope; Glavina Del Rio, Tijana; Cheng, Jan-Fang; Han, Cliff; Tapia, Roxanne; Goodwin, Lynne A.; Pitluck, Sam; Liolios, Konstantinos; Mavromatis, K; Pagani, Ioanna; Ivanova, N; Mikhailova, Natalia; Pati, Amrita; Chen, Amy; Palaniappan, Krishna; Land, Miriam L; Hauser, Loren John; Jeffries, Cynthia; Chang, Yun-Juan; Brambilla, Evelyne-Marie; Rohde, Manfred; Spring, Stefan; Goker, Markus; Detter, J. Chris; Woyke, Tanja; Bristow, James; Eisen, Jonathan; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C; Klenk, Hans-Peter

    2012-01-01

    Thermodesulfatator indicus Moussard et al. 2004 is a member of the genomically so far poorly characterized family Thermodesulfobacteriaceae in the phylum Thermodesulfobacteria. Members of this phylum are of interest because they represent a distinct, deep-branching, Gram-negative lineage. T. indicus is an anaerobic, thermophilic, chemolithoautotrophic sulfate reducer isolated from a deep-sea hydrothermal vent. Here we describe the features of this organism, together with the complete genome sequence, and annotation. The 2,322,224 bp long chromosome with its 2,233 protein-coding and 58 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

  8. Molecular analysis of the metabolic rates of discrete subsurface populations of sulfate reducers

    SciTech Connect

    Miletto, M.; Williams, K.H.; N'Guessan, A.L.; Lovley, D.R.

    2011-04-01

    Elucidating the in situ metabolic activity of phylogenetically diverse populations of sulfate-reducing microorganisms that populate anoxic sedimentary environments is key to understanding subsurface ecology. Previous pure culture studies have demonstrated that transcript abundance of dissimilatory (bi)sulfite reductase genes is correlated with the sulfate reducing activity of individual cells. To evaluate whether expression of these genes was diagnostic for subsurface communities, dissimilatory (bi)sulfite reductase gene transcript abundance in phylogenetically distinct sulfate-reducing populations was quantified during a field experiment in which acetate was added to uranium-contaminated groundwater. Analysis of dsrAB sequences prior to the addition of acetate indicated that Desulfobacteraceae, Desulfobulbaceae, and Syntrophaceae-related sulfate reducers were the most abundant. Quantifying dsrB transcripts of the individual populations suggested that Desulfobacteraceae initially had higher dsrB transcripts per cell than Desulfobulbaceae or Syntrophaceae populations, and that the activity of Desulfobacteraceae increased further when the metabolism of dissimilatory metal reducers competing for the added acetate declined. In contrast, dsrB transcript abundance in Desulfobulbaceae and Syntrophaceae remained relatively constant, suggesting a lack of stimulation by added acetate. The indication of higher sulfate-reducing activity in the Desulfobacteraceae was consistent with the finding that Desulfobacteraceae became the predominant component of the sulfate-reducing community. Discontinuing acetate additions resulted in a decline in dsrB transcript abundance in the Desulfobacteraceae. These results suggest that monitoring transcripts of dissimilatory (bi)sulfite reductase genes in distinct populations of sulfate reducers can provide insight into the relative rates of metabolism of different components of the sulfate-reducing community and their ability to respond to

  9. The Effect of Temperature and Hydrogen Limited Growth on the Fractionation of Sulfur Isotopes by Thermodesulfatator indicus, a Deep-sea Hydrothermal Vent Sulfate-Reducing Bacterium

    NASA Astrophysics Data System (ADS)

    Hoek, J.; Reysenbach, A.; Habicht, K.; Canfield, D. E.

    2004-12-01

    Sulfate-reducing bacteria fractionate sulfur isotopes during dissimilatory sulfate reduction, producing sulfide depleted in 34S. Although isotope fractionation during sulfate reduction of pure cultures has been extensively studied, most of the research to date has focused on mesophilic sulfate reducers, particularly for the species Desulfovibrio desulfuricans. Results from these studies show that: 1) fractionations range from 3-46‰ with an average around 18‰ , 2) when organic electron donors are utilized, the extent of fractionation is dependent on the rate of sulfate reduction, with decreasing fractionations observed with higher specific rates, 3) fractionations are suppressed with low sulfate concentrations, and when hydrogen is used as the electron donor. High specific sulfate-reduction rates are encountered when sulfate-reducing bacteria metabolize at their optimal temperature and under non-limiting substrate conditions. Changes in both temperature and substrate availability could shift fractionations from those expressed under optimal growth conditions. Sulfate reducers may frequently experience substrate limitation and sub-optimal growth temperatures in the environment. Therefore it is important to understand how sulfate-reducing bacteria fractionate sulfur isotopes under conditions that more closely resemble the restrictions imposed by the environment. In this study the fractionation of sulfur isotopes by Thermodesulfatator indicus was explored during sulfate reduction under a wide range of temperatures and with both hydrogen-saturating and hydrogen-limited conditions. T. indicus is a thermophilic (temperature optimum = 70° C) chemolithotrophic sulfate-reducing bacterium, which was recently isolated from a deep-sea hydrothermal vent on the Central Indian Ridge. This bacterium represents the type species of a new genus and to date is the most deeply branching sulfate-reducing bacterium known. T. indicus was grown in carbonate-buffered salt-water medium

  10. Temperature-Dependent Variations in Sulfate-Reducing Communities Associated with a Terrestrial Hydrocarbon Seep

    PubMed Central

    Cheng, Ting-Wen; Lin, Li-Hung; Lin, Yue-Ting; Song, Sheng-Rong; Wang, Pei-Ling

    2014-01-01

    Terrestrial hydrocarbon seeps are an important source of naturally emitted methane over geological time. The exact community compositions responsible for carbon cycling beneath these surface features remain obscure. As sulfate reduction represents an essential process for anoxic organic mineralization, this study collected muddy fluids from a high-temperature hydrocarbon seep in Taiwan and analyzed community structures of sulfate-supplemented sediment slurries incubated anoxically at elevated temperatures. The results obtained demonstrated that sulfate consumption occurred between 40°C and 80°C. Dominant potential sulfate reducers included Desulfovibrio spp., Desulfonatronum spp., Desulforhabdus spp., and Desulfotomaculum spp. at 40°C, Thermodesulfovibrio spp. at 50°C, Thermodesulfovibrio spp. and Thermacetogenium spp. at 60°C, Thermacetogenium spp. and Archaeoglobus spp. at 70°C, and Archaeoglobus spp. at 80°C. None of these potential sulfate reducers exceeded 7% of the community in the untreated sample. Since no exogenous electron donor was provided during incubation, these sulfate reducers appeared to rely on the degradation of organic matter inherited from porewater and sediments. Aqueous chemistry indicated that fluids discharged in the region represented a mixture of saline formation water and low-salinity surface water; therefore, these lines of evidence suggest that deeply-sourced, thermophilic and surface-input, mesophilic sulfate-reducing populations entrapped along the subsurface fluid transport could respond rapidly once the ambient temperature is adjusted to a range close to their individual optima. PMID:25273230

  11. Evidence that crude oil alkane activation proceeds by different mechanisms under sulfate-reducing and methanogenic conditions

    NASA Astrophysics Data System (ADS)

    Aitken, C. M.; Jones, D. M.; Maguire, M. J.; Gray, N. D.; Sherry, A.; Bowler, B. F. J.; Ditchfield, A. K.; Larter, S. R.; Head, I. M.

    2013-05-01

    Fumarate addition has been widely proposed as an initial step in the anaerobic oxidation of both aromatic and aliphatic hydrocarbons. Alkyl and aryl succinates have been reported as metabolites of hydrocarbon degradation in laboratory studies with both pure and enrichment cultures of sulfate-, nitrate-, and iron-reducing bacteria. In addition these compounds have been reported in samples from environments such as hydrocarbon contaminated aquifers where, in addition to the above redox processes, hydrocarbon degradation linked to methanogenesis was observed. Here we report data from anaerobic crude oil degrading microcosms which revealed significant differences between the acid metabolite profiles of crude oil degraded under sulfate-reducing or methanogenic conditions. Under sulfate-reducing conditions fumarate addition and the formation of alkylsuccinate metabolites was the principal mechanism for the anaerobic degradation of n-alkanes and branched chain alkanes. Other than alkyl succinates that represent indigenous metabolites in the sediment inoculum, alkyl succinate metabolites were never detected in sediment microcosms where methane generation was quantitatively linked to n-alkane degradation. This indicates that alternative mechanisms of alkane activation may operate under methanogenic conditions.

  12. Identification and catalytic residues of the arsenite methyltransferase from a sulfate-reducing bacterium, Clostridium sp. BXM.

    PubMed

    Wang, Pei-Pei; Bao, Peng; Sun, Guo-Xin

    2015-01-01

    Arsenic methylation is an important process frequently occurring in anaerobic environments. Anaerobic microorganisms have been implicated as the major contributors for As methylation. However, very little information is available regarding the enzymatic mechanism of As methylation by anaerobes. In this study, one novel sulfate-reducing bacterium isolate, Clostridium sp. BXM, which was isolated from a paddy soil in our laboratory, was demonstrated to have the ability of methylating As. One putative arsenite S-Adenosyl-Methionine methyltransferase (ArsM) gene, CsarsM was cloned from Clostridium sp. BXM. Heterologous expression of CsarsM conferred As resistance and the ability of methylating As to an As-sensitive strain of Escherichia coli. Purified methyltransferase CsArsM catalyzed the formation of methylated products from arsenite, further confirming its function of As methylation. Site-directed mutagenesis studies demonstrated that three conserved cysteine residues at positions 65, 153 and 203 in CsArsM are necessary for arsenite methylation, but only Cysteine 153 and Cysteine 203 are required for the methylation of monomethylarsenic to dimethylarsenic. These results provided the characterization of arsenic methyltransferase from anaerobic sulfate-reducing bacterium. Given that sulfate-reducing bacteria are ubiquitous in various wetlands including paddy soils, enzymatic methylation mediated by these anaerobes is proposed to contribute to the arsenic biogeochemical cycling. PMID:25790486

  13. Monitoring structural transformation of hydroxy-sulphate green rust in the presence of sulphate reducing bacteria

    NASA Astrophysics Data System (ADS)

    Abdelmoula, M.; Zegeye, A.; Jorand, F.; Carteret, C.

    2006-01-01

    The activities of bacterial consortia enable organisms to maximize their metabolic capabilities. This article assesses the synergetic relationship between iron reducing bacteria (IRB), Shewanella putrefaciens and sulphate reducing bacteria (SRB) Desulfovibrio alaskensis. Thus, the aim of this study was first to form a biogenic hydroxy-sulpahte green rust GR2( {text{SO}}_{{text{4}}} ^{{2 - }} ) through the bioreduction of lepidocrocite by S. putrefaciens and secondly to investigate if sulfate anions intercalated in the biogenic GR2( {text{SO}}_{{text{4}}} ^{{2 - }} ) could serve as final electron acceptor for a sulfate reducing bacterium, D. alaskensis. The results indicate that the IRB lead to the formation of GR2( {text{SO}}_{{text{4}}} ^{{2 - }} ) and this mineral serve as an electron acceptor for SRB. GR2( {text{SO}}_{{text{4}}} ^{{2 - }} ) precipitation and its transformation was demonstrated by using X-ray diffraction (DRX), Mössbauer spectroscopy (TMS) and transmission electron spectroscopy (TEM). These observations point out the possible acceleration of steel corrosion in marine environment in presence of IRB/SRB consortia.

  14. Monitoring structural transformation of hydroxy-sulphate green rust in the presence of sulphate reducing bacteria

    NASA Astrophysics Data System (ADS)

    Abdelmoula, M.; Zegeye, A.; Jorand, F.; Carteret, C.

    The activities of bacterial consortia enable organisms to maximize their metabolic capabilities. This article assesses the synergetic relationship between iron reducing bacteria (IRB), Shewanella putrefaciens and sulphate reducing bacteria (SRB) Desulfovibrio alaskensis. Thus, the aim of this study was first to form a biogenic hydroxysulpahte green rust GR2(SO{4/2-}) through the bioreduction of lepidocrocite by S. putrefaciens and secondly to investigate if sulfate anions intercalated in the biogenic GR2(SO{4/2-}) could serve as final electron acceptor for a sulfate reducing bacterium, D. alaskensis. The results indicate that the IRB lead to the formation of GR2(SO{4/2-}) and this mineral serve as an electron acceptor for SRB. GR2(SO{4/2-}) precipitation and its transformation was demonstrated by using X-ray diffraction (DRX), Mössbauer spectroscopy (TMS) and transmission electron spectroscopy (TEM). These observations point out the possible acceleration of steel corrosion in marine environment in presence of IRB/SRB consortia.

  15. High-Quality Draft Genome Sequence of Desulfovibrio carbinoliphilus FW-101-2B, an Organic Acid-Oxidizing Sulfate-Reducing Bacterium Isolated from Uranium(VI)-Contaminated Groundwater

    PubMed Central

    Ramsay, Bradley D.; Hwang, Chiachi; Carroll, Sue L.; Lucas, Susan; Han, James; Lapidus, Alla L.; Cheng, Jan-Fang; Goodwin, Lynne A.; Pitluck, Samuel; Peters, Lin; Chertkov, Olga; Held, Brittany; Detter, John C.; Han, Cliff S.; Tapia, Roxanne; Land, Miriam L.; Hauser, Loren J.; Kyrpides, Nikos C.; Ivanova, Natalia N.; Mikhailova, Natalia; Pagani, Ioanna; Woyke, Tanja; Arkin, Adam P.; Dehal, Paramvir; Chivian, Dylan; Criddle, Craig S.; Wu, Weimin; Chakraborty, Romy

    2015-01-01

    Desulfovibrio carbinoliphilus subsp. oakridgensis FW-101-2B is an anaerobic, organic acid/alcohol-oxidizing, sulfate-reducing δ-proteobacterium. FW-101-2B was isolated from contaminated groundwater at The Field Research Center at Oak Ridge National Lab after in situ stimulation for heavy metal-reducing conditions. The genome will help elucidate the metabolic potential of sulfate-reducing bacteria during uranium reduction. PMID:25767232

  16. High-Quality Draft Genome Sequence of Desulfovibrio carbinoliphilus FW-101-2B, an Organic Acid-Oxidizing Sulfate-Reducing Bacterium Isolated from Uranium(VI)-Contaminated Groundwater

    DOE PAGESBeta

    Ramsay, Bradley D.; Hwang, Chiachi; Woo, Hannah L.; Carroll, Sue L.; Lucas, Susan; Han, James; Lapidus, Alla L.; Cheng, Jan-Fang; Goodwin, Lynne A.; Pitluck, Samuel; et al

    2015-03-12

    Desulfovibrio carbinoliphilus subsp. oakridgensis FW-101-2B is an anaerobic, organic acid/alcohol-oxidizing, sulfate-reducing δ-proteobacterium. FW-101-2B was isolated from contaminated groundwater at The Field Research Center at Oak Ridge National Lab after in situ stimulation for heavy metal-reducing conditions. The genome will help elucidate the metabolic potential of sulfate-reducing bacteria during uranium reduction.

  17. Microbial reduction of structural iron in interstratified illite-smectite minerals by a sulfate-reducing bacterium.

    PubMed

    Liu, D; Dong, H; Bishop, M E; Zhang, J; Wang, H; Xie, S; Wang, S; Huang, L; Eberl, D D

    2012-03-01

    Clay minerals are ubiquitous in soils, sediments, and sedimentary rocks and could coexist with sulfate-reducing bacteria (SRB) in anoxic environments, however, the interactions of clay minerals and SRB are not well understood. The objective of this study was to understand the reduction rate and capacity of structural Fe(III) in dioctahedral clay minerals by a mesophilic SRB, Desulfovibrio vulgaris and the potential role in catalyzing smectite illitization. Bioreduction experiments were performed in batch systems, where four different clay minerals (nontronite NAu-2, mixed-layer illite-smectite RAr-1 and ISCz-1, and illite IMt-1) were exposed to D. vulgaris in a non-growth medium with and without anthraquinone-2,6-disulfonate (AQDS) and sulfate. Our results demonstrated that D. vulgaris was able to reduce structural Fe(III) in these clay minerals, and AQDS enhanced the reduction rate and extent. In the presence of AQDS, sulfate had little effect on Fe(III) bioreduction. In the absence of AQDS, sulfate increased the reduction rate and capacity, suggesting that sulfide produced during sulfate reduction reacted with the phyllosilicate Fe(III). The extent of bioreduction of structural Fe(III) in the clay minerals was positively correlated with the percentage of smectite and mineral surface area of these minerals. X-ray diffraction, and scanning and transmission electron microscopy results confirmed formation of illite after bioreduction. These data collectively showed that D. vulgaris could promote smectite illitization through reduction of structural Fe(III) in clay minerals. PMID:22074236

  18. Microbial reduction of structural iron in interstratified illite-smectite minerals by a sulfate-reducing bacterium

    USGS Publications Warehouse

    Liu, D.; Dong, H.; Bishop, M.E.; Zhang, Jiahua; Wang, Hongfang; Xie, S.; Wang, Shaoming; Huang, L.; Eberl, D.D.

    2012-01-01

    Clay minerals are ubiquitous in soils, sediments, and sedimentary rocks and could coexist with sulfate-reducing bacteria (SRB) in anoxic environments, however, the interactions of clay minerals and SRB are not well understood. The objective of this study was to understand the reduction rate and capacity of structural Fe(III) in dioctahedral clay minerals by a mesophilic SRB, Desulfovibrio vulgaris and the potential role in catalyzing smectite illitization. Bioreduction experiments were performed in batch systems, where four different clay minerals (nontronite NAu-2, mixed-layer illite-smectite RAr-1 and ISCz-1, and illite IMt-1) were exposed to D. vulgaris in a non-growth medium with and without anthraquinone-2,6-disulfonate (AQDS) and sulfate. Our results demonstrated that D. vulgaris was able to reduce structural Fe(III) in these clay minerals, and AQDS enhanced the reduction rate and extent. In the presence of AQDS, sulfate had little effect on Fe(III) bioreduction. In the absence of AQDS, sulfate increased the reduction rate and capacity, suggesting that sulfide produced during sulfate reduction reacted with the phyllosilicate Fe(III). The extent of bioreduction of structural Fe(III) in the clay minerals was positively correlated with the percentage of smectite and mineral surface area of these minerals. X-ray diffraction, and scanning and transmission electron microscopy results confirmed formation of illite after bioreduction. These data collectively showed that D. vulgaris could promote smectite illitization through reduction of structural Fe(III) in clay minerals. ?? 2011 Blackwell Publishing Ltd.

  19. Example study for granular bioreactor stratification: Three-dimensional evaluation of a sulfate-reducing granular bioreactor.

    PubMed

    Hao, Tian-Wei; Luo, Jing-Hai; Su, Kui-Zu; Wei, Li; Mackey, Hamish R; Chi, Kun; Chen, Guang-Hao

    2016-01-01

    Recently, sulfate-reducing granular sludge has been developed for application in sulfate-laden water and wastewater treatment. However, little is known about biomass stratification and its effects on the bioprocesses inside the granular bioreactor. A comprehensive investigation followed by a verification trial was therefore conducted in the present work. The investigation focused on the performance of each sludge layer, the internal hydrodynamics and microbial community structures along the height of the reactor. The reactor substratum (the section below baffle 1) was identified as the main acidification zone based on microbial analysis and reactor performance. Two baffle installations increased mixing intensity but at the same time introduced dead zones. Computational fluid dynamics simulation was employed to visualize the internal hydrodynamics. The 16S rRNA gene of the organisms further revealed that more diverse communities of sulfate-reducing bacteria (SRB) and acidogens were detected in the reactor substratum than in the superstratum (the section above baffle 1). The findings of this study shed light on biomass stratification in an SRB granular bioreactor to aid in the design and optimization of such reactors. PMID:27539264

  20. Example study for granular bioreactor stratification: Three-dimensional evaluation of a sulfate-reducing granular bioreactor

    PubMed Central

    Hao, Tian-wei; Luo, Jing-hai; Su, Kui-zu; Wei, Li; Mackey, Hamish R.; Chi, Kun; Chen, Guang-Hao

    2016-01-01

    Recently, sulfate-reducing granular sludge has been developed for application in sulfate-laden water and wastewater treatment. However, little is known about biomass stratification and its effects on the bioprocesses inside the granular bioreactor. A comprehensive investigation followed by a verification trial was therefore conducted in the present work. The investigation focused on the performance of each sludge layer, the internal hydrodynamics and microbial community structures along the height of the reactor. The reactor substratum (the section below baffle 1) was identified as the main acidification zone based on microbial analysis and reactor performance. Two baffle installations increased mixing intensity but at the same time introduced dead zones. Computational fluid dynamics simulation was employed to visualize the internal hydrodynamics. The 16S rRNA gene of the organisms further revealed that more diverse communities of sulfate-reducing bacteria (SRB) and acidogens were detected in the reactor substratum than in the superstratum (the section above baffle 1). The findings of this study shed light on biomass stratification in an SRB granular bioreactor to aid in the design and optimization of such reactors. PMID:27539264

  1. Regulation of Nitrite Stress Response in Desulfovibrio vulgaris Hildenborough, a Model Sulfate-Reducing Bacterium

    PubMed Central

    Rajeev, Lara; Chen, Amy; Kazakov, Alexey E.; Luning, Eric G.; Zane, Grant M.; Novichkov, Pavel S.; Wall, Judy D.

    2015-01-01

    ABSTRACT Sulfate-reducing bacteria (SRB) are sensitive to low concentrations of nitrite, and nitrite has been used to control SRB-related biofouling in oil fields. Desulfovibrio vulgaris Hildenborough, a model SRB, carries a cytochrome c-type nitrite reductase (nrfHA) that confers resistance to low concentrations of nitrite. The regulation of this nitrite reductase has not been directly examined to date. In this study, we show that DVU0621 (NrfR), a sigma54-dependent two-component system response regulator, is the positive regulator for this operon. NrfR activates the expression of the nrfHA operon in response to nitrite stress. We also show that nrfR is needed for fitness at low cell densities in the presence of nitrite because inactivation of nrfR affects the rate of nitrite reduction. We also predict and validate the binding sites for NrfR upstream of the nrfHA operon using purified NrfR in gel shift assays. We discuss possible roles for NrfR in regulating nitrate reductase genes in nitrate-utilizing Desulfovibrio spp. IMPORTANCE The NrfA nitrite reductase is prevalent across several bacterial phyla and required for dissimilatory nitrite reduction. However, regulation of the nrfA gene has been studied in only a few nitrate-utilizing bacteria. Here, we show that in D. vulgaris, a bacterium that does not respire nitrate, the expression of nrfHA is induced by NrfR upon nitrite stress. This is the first report of regulation of nrfA by a sigma54-dependent two-component system. Our study increases our knowledge of nitrite stress responses and possibly of the regulation of nitrate reduction in SRB. PMID:26283774

  2. Changes in sulfate-reducing bacterial populations during the onset of black band disease.

    PubMed

    Bourne, David G; Muirhead, Andrew; Sato, Yui

    2011-03-01

    Factors that facilitate the onset of black band disease (BBD) of corals remain elusive, though anoxic conditions under the complex microbial mat and production of sulfide are implicated in necrosis of underlying coral tissues. This study investigated the diversity and quantitative shifts of sulfate-reducing bacterial (SRB) populations during the onset of BBD using real-time PCR (RT-PCR) and cloning approaches targeting the dissimilatory (bi)sulfite reductase (dsrA) gene. A quantitative-PCR (qPCR) assay targeting the 16S rRNA gene also provided an estimate of total bacteria, and allowed the relative percentage of SRB within the lesions to be determined. Three Montipora sp. coral colonies identified with lesions previously termed cyanobacterial patches (CPs) (comprising microbial communities unlike those of BBD lesions), were tagged and followed through time as CP developed into BBD. The dsrA-targeted qPCR detected few copies of the gene in the CP samples (<65 per ng DNA), though copy numbers increased in BBD lesions (>2500 per ng DNA). SRB in CP samples were less than 1% of the bacterial population, though represented up to 7.5% of the BBD population. Clone libraries also demonstrated a shift in the dominant dsrA sequences as lesions shifted from CP into BBD. Results from this study confirm that SRB increase during the onset of BBD, likely increasing sulfide concentrations at the base of the microbial mat and facilitating the pathogenesis of BBD. PMID:20811471

  3. Changes in sulfate-reducing bacterial populations during the onset of black band disease

    PubMed Central

    Bourne, David G; Muirhead, Andrew; Sato, Yui

    2011-01-01

    Factors that facilitate the onset of black band disease (BBD) of corals remain elusive, though anoxic conditions under the complex microbial mat and production of sulfide are implicated in necrosis of underlying coral tissues. This study investigated the diversity and quantitative shifts of sulfate-reducing bacterial (SRB) populations during the onset of BBD using real-time PCR (RT-PCR) and cloning approaches targeting the dissimilatory (bi)sulfite reductase (dsrA) gene. A quantitativePCR (qPCR) assay targeting the 16S rRNA gene also provided an estimate of total bacteria, and allowed the relative percentage of SRB within the lesions to be determined. Three Montipora sp. coral colonies identified with lesions previously termed cyanobacterial patches (CPs) (comprising microbial communities unlike those of BBD lesions), were tagged and followed through time as CP developed into BBD. The dsrA-targeted qPCR detected few copies of the gene in the CP samples (<65 per ng DNA), though copy numbers increased in BBD lesions (>2500 per ng DNA). SRB in CP samples were less than 1% of the bacterial population, though represented up to 7.5% of the BBD population. Clone libraries also demonstrated a shift in the dominant dsrA sequences as lesions shifted from CP into BBD. Results from this study confirm that SRB increase during the onset of BBD, likely increasing sulfide concentrations at the base of the microbial mat and facilitating the pathogenesis of BBD. PMID:20811471

  4. Biomolecular and Isotopic Signatures Related to Cr(VI) Reduction by a Sulfate-Reducing Bacterium Isolated from the Hanford 100H Aquifer

    NASA Astrophysics Data System (ADS)

    Han, R.; Qin, L.; Geller, J. T.; Chakraborty, R.; Christensen, J. N.; Beller, H. R.

    2011-12-01

    Chromium contamination of groundwater is widespread within the Dept. of Energy (DOE) complex. At DOE's Hanford 100H area, we have conducted Cr bioremediation (in situ reductive immobilization) studies involving injection of a lactate-containing polymer, and have observed sequential use of the dissolved electron acceptors present in groundwater (namely, oxygen, nitrate, and sulfate). Sulfate-reducing bacteria are of particular interest for chromate reduction because they can reduce Cr(VI) enzymatically (e.g., using cytochrome c3 or thioredoxin reductase) and abiotically with hydrogen sulfide, the end product of their respiration. In this poster, we use studies of a sulfate-reducing bacterium isolated from the Hanford 100H aquifer, Desulfovibrio vulgaris strain RCH1, to explore (a) isotopic signatures that might allow us to distinguish between enzymatic and sulfide-mediated Cr(VI) reduction and (b) biomolecular signatures (gene or transcript copy number of diagnostic genes) that might be used as proxies of in situ metabolic rates. In order to differentiate between the mechanisms of Cr reduction by sulfate reducers, we analyzed the isotopic fractionation during Cr(VI) reduction by strain RCH1. Cell suspension studies of strain RCH1 demonstrated that Cr(VI) reduction could occur in the presence of lactate (electron donor) alone or with both lactate and sulfate. Cr(VI) reduction in the presence of lactate and sulfate was 25-30% more rapid than enzymatic Cr reduction when only lactate was added, suggesting that biogenic hydrogen sulfide increases the specific rate of Cr(VI) reduction beyond purely enzymatic activity. Cr isotopic measurements showed different fractionation behavior for the lactate-only and lactate+sulfate systems, with fractionation (epsilon) values of 2.3 and 1.66 per mil, respectively. In order to determine whether gene or transcript copy number for diagnostic sulfate and chromate reduction genes could serve as proxies to estimate in situ metabolic

  5. Elucidating microbial processes in nitrate- and sulfate-reducing systems using sulfur and oxygen isotope ratios: The example of oil reservoir souring control

    NASA Astrophysics Data System (ADS)

    Hubert, Casey; Voordouw, Gerrit; Mayer, Bernhard

    2009-07-01

    Sulfate-reducing bacteria (SRB) are ubiquitous in anoxic environments where they couple the oxidation of organic compounds to the production of hydrogen sulfide. This can be problematic for various industries including oil production where reservoir "souring" (the generation of H 2S) requires corrective actions. Nitrate or nitrite injection into sour oil fields can promote SRB control by stimulating organotrophic nitrate- or nitrite-reducing bacteria (O-NRB) that out-compete SRB for electron donors (biocompetitive exclusion), and/or by lithotrophic nitrate- or nitrite-reducing sulfide oxidizing bacteria (NR-SOB) that remove H 2S directly. Sulfur and oxygen isotope ratios of sulfide and sulfate were monitored in batch cultures and sulfidic bioreactors to evaluate mitigation of SRB activities by nitrate or nitrite injection. Sulfate reduction in batch cultures of Desulfovibrio sp. strain Lac15 indicated typical Rayleigh-type fractionation of sulfur isotopes during bacterial sulfate reduction (BSR) with lactate, whereas oxygen isotope ratios in unreacted sulfate remained constant. Sulfur isotope fractionation in batch cultures of the NR-SOB Thiomicrospira sp. strain CVO was minimal during the oxidation of sulfide to sulfate, which had δ18O SO4 values similar to that of the water-oxygen. Treating an up-flow bioreactor with increasing doses of nitrate to eliminate sulfide resulted in changes in sulfur isotope ratios of sulfate and sulfide but very little variation in oxygen isotope ratios of sulfate. These observations were similar to results obtained from SRB-only, but different from those of NR-SOB-only pure culture control experiments. This suggests that biocompetitive exclusion of SRB took place in the nitrate-injected bioreactor. In two replicate bioreactors treated with nitrite, less pronounced sulfur isotope fractionation and a slight decrease in δ18O SO4 were observed. This indicated that NR-SOB played a minor role during dosing with low nitrite and that

  6. Microbial mineralization of ethene under sulfate-reducing conditions

    USGS Publications Warehouse

    Bradley, P.M.; Chapelle, F.H.

    2002-01-01

    A limited investigation of the potential for anaerobic ethylene biodegradation under SO4-reducing conditions was performed. Microorganisms indigenous to a lake-bed sediment completely mineralized [1,2-14C] ethylene to 14CO2 when incubated under SO4-reducing conditions. Reliance on ethylene and/or ethane accumulation as a quantitative indicator of complete reductive dechlorination of chloroethylene contaminants may not be warranted. SO4 addition stimulated SO4 reduction as indicated by decreasing SO4 concentrations (> 40% decrease) and production of dissolved sulfide (880 ??M). SO4 amendment completely suppressed the production of ethane and methane. The concomitant absence of ethane and methane production under SO4-amended conditions was consistent with previous conclusions that reduction of ethylene to ethane occurred under methanogenic conditions. A lack of ethylene accumulation under SO4-reducing conditions may reflect insignificant reductive dechlorination of vinyl chloride or efficient anaerobic mineralization of ethylene to CO2.

  7. Biochemical and Molecular Characterization of Potential Phosphate-Solubilizing Bacteria in Acid Sulfate Soils and Their Beneficial Effects on Rice Growth

    PubMed Central

    Panhwar, Qurban Ali; Naher, Umme Aminun; Jusop, Shamshuddin; Othman, Radziah; Latif, Md Abdul; Ismail, Mohd Razi

    2014-01-01

    A study was conducted to determine the total microbial population, the occurrence of growth promoting bacteria and their beneficial traits in acid sulfate soils. The mechanisms by which the bacteria enhance rice seedlings grown under high Al and low pH stress were investigated. Soils and rice root samples were randomly collected from four sites in the study area (Kelantan, Malaysia). The topsoil pH and exchangeable Al ranged from 3.3 to 4.7 and 1.24 to 4.25 cmolc kg−1, respectively, which are considered unsuitable for rice production. Total bacterial and actinomycetes population in the acidic soils were found to be higher than fungal populations. A total of 21 phosphate-solubilizing bacteria (PSB) including 19 N2-fixing strains were isolated from the acid sulfate soil. Using 16S rRNA gene sequence analysis, three potential PSB strains based on their beneficial characteristics were identified (Burkholderia thailandensis, Sphingomonas pituitosa and Burkholderia seminalis). The isolated strains were capable of producing indoleacetic acid (IAA) and organic acids that were able to reduce Al availability via a chelation process. These PSB isolates solubilized P (43.65%) existing in the growth media within 72 hours of incubation. Seedling of rice variety, MR 219, grown at pH 4, and with different concentrations of Al (0, 50 and 100 µM) was inoculated with these PSB strains. Results showed that the bacteria increased the pH with a concomitant reduction in Al concentration, which translated into better rice growth. The improved root volume and seedling dry weight of the inoculated plants indicated the potential of these isolates to be used in a bio-fertilizer formulation for rice cultivation on acid sulfate soils. PMID:25285745

  8. Biochemical and molecular characterization of potential phosphate-solubilizing bacteria in acid sulfate soils and their beneficial effects on rice growth.

    PubMed

    Panhwar, Qurban Ali; Naher, Umme Aminun; Shamshuddin, Jusop; Jusop, Shamshuddin; Othman, Radziah; Latif, Md Abdul; Ismail, Mohd Razi

    2014-01-01

    A study was conducted to determine the total microbial population, the occurrence of growth promoting bacteria and their beneficial traits in acid sulfate soils. The mechanisms by which the bacteria enhance rice seedlings grown under high Al and low pH stress were investigated. Soils and rice root samples were randomly collected from four sites in the study area (Kelantan, Malaysia). The topsoil pH and exchangeable Al ranged from 3.3 to 4.7 and 1.24 to 4.25 cmol(c) kg(-1), respectively, which are considered unsuitable for rice production. Total bacterial and actinomycetes population in the acidic soils were found to be higher than fungal populations. A total of 21 phosphate-solubilizing bacteria (PSB) including 19 N2-fixing strains were isolated from the acid sulfate soil. Using 16S rRNA gene sequence analysis, three potential PSB strains based on their beneficial characteristics were identified (Burkholderia thailandensis, Sphingomonas pituitosa and Burkholderia seminalis). The isolated strains were capable of producing indoleacetic acid (IAA) and organic acids that were able to reduce Al availability via a chelation process. These PSB isolates solubilized P (43.65%) existing in the growth media within 72 hours of incubation. Seedling of rice variety, MR 219, grown at pH 4, and with different concentrations of Al (0, 50 and 100 µM) was inoculated with these PSB strains. Results showed that the bacteria increased the pH with a concomitant reduction in Al concentration, which translated into better rice growth. The improved root volume and seedling dry weight of the inoculated plants indicated the potential of these isolates to be used in a bio-fertilizer formulation for rice cultivation on acid sulfate soils. PMID:25285745

  9. Response And Recovery Of Sulfate-Reducing Biochemical Reactors From Aerobic Stress Events

    EPA Science Inventory

    Microbially-mediated treatment of mining-influenced water (MIW) through the implementation of sulfate-reducing biochemical reactors (BCRs) is an attractive option for passive, in situ remediation with low operating costs and reduced maintenance requirements. However, BCRs can be...

  10. Response And Recovery Of Sulfate-Reducing Biochemical Reactors From Aerobic Stress Events (Presentation)

    EPA Science Inventory

    Microbially-mediated treatment of mining-influenced water (MIW) through the implementation of sulfate-reducing biochemical reactors (BCR) is an attractive option for passive, in situ remediation with low operating costs and reduced maintenance requirements. However, BCRs can be ...

  11. A sulfated polysaccharide, fucoidan, enhances the immunomodulatory effects of lactic acid bacteria.

    PubMed

    Kawashima, Tadaomi; Murakami, Katsura; Nishimura, Ikuko; Nakano, Takahisa; Obata, Akio

    2012-03-01

    Fucoidan, a sulfated polysaccharide contained in brown algae, has a variety of immunomodulatory effects, including antitumor and antiviral effects. On the other hand, lactic acid bacteria (LAB) also have immunomodulatory effects such as anti-allergic effects. In this study, we demonstrated that fucoidan enhances the probiotic effects of LAB on immune functions. By using Peyer's patch cells and spleen cells in vitro, fucoidan amplified interferon (IFN)-γ production in response to a strain of LAB, Tetragenococcus halophilus KK221, and this activity was abolished by desulfation of fucoidan. Moreover, this IFN-γ response was abolished by interleukin (IL)-12 neutralization. These results indicate that fucoidan enhanced IL-12 production in response to KK221, resulting in promoting IFN-γ production. In an in vivo study, Th1/Th2 immunobalance was most improved by oral administration of both fucoidan and KK221 to ovalbumin-immunized mice. These findings suggest that fucoidan can enhance a variety of beneficial effects of LAB on immune functions. PMID:22160132

  12. Anaerobic Cometabolic Conversion of Benzothiophene by a Sulfate-Reducing Enrichment Culture and in a Tar-Oil-Contaminated Aquifer†

    PubMed Central

    Annweiler, Eva; Michaelis, Walter; Meckenstock, Rainer U.

    2001-01-01

    Anaerobic cometabolic conversion of benzothiophene was studied with a sulfate-reducing enrichment culture growing with naphthalene as the sole source of carbon and energy. The sulfate-reducing bacteria were not able to grow with benzothiophene as the primary substrate. Metabolite analysis was performed with culture supernatants obtained by cometabolization experiments and revealed the formation of three isomeric carboxybenzothiophenes. Two isomers were identified as 2-carboxybenzothiophene and 5-carboxybenzothiophene. In some experiments, further reduced dihydrocarboxybenzothiophene was identified. No other products of benzothiophene degradation could be determined. In isotope-labeling experiments with a [13C]bicarbonate-buffered culture medium, carboxybenzothiophenes which were significantly enriched in the 13C content of the carboxyl group were formed, indicating the addition of a C1 unit from bicarbonate to benzothiophene as the initial activation reaction. This finding was consistent with the results of earlier studies on anaerobic naphthalene degradation with the same culture, and we therefore propose that benzothiophene was cometabolically converted by the same enzyme system. Groundwater analyses of the tar-oil-contaminated aquifer from which the naphthalene-degrading enrichment culture was isolated exhibited the same carboxybenzothiophene isomers as the culture supernatants. In addition, the benzothiophene degradation products, in particular, dihydrocarboxybenzothiophene, were significantly enriched in the contaminated groundwater to concentrations almost the same as those of the parent compound, benzothiophene. The identification of identical metabolites of benzothiophene conversion in the sulfate-reducing enrichment culture and in the contaminated aquifer indicated that the same enzymatic reactions were responsible for the conversion of benzothiophene in situ. PMID:11679329

  13. Anaerobic biodegradation of soybean biodiesel and diesel blends under sulfate-reducing conditions.

    PubMed

    Wu, Shuyun; Yassine, Mohamad H; Suidan, Makram T; Venosa, Albert D

    2016-10-01

    Biotransformation of soybean biodiesel and its biodiesel/petrodiesel blends were investigated under sulfate-reducing conditions. Three blends of biodiesel, B100, B50, and B0, were treated using microbial cultures pre-acclimated to B100 (biodiesel only) and B80 (80% biodiesel and 20% petrodiesel). Results indicate that the biodiesel could be effectively biodegraded in the presence or absence of petrodiesel, whereas petrodiesel could not be biodegraded at all under sulfate-reducing conditions. The kinetics of biodegradation of individual Fatty Acid Methyl Ester (FAME) compounds and their accompanying sulfate-reduction rates were studied using a serum bottle test. As for the biodegradation of individual FAME compounds, the biodegradation rates for the saturated FAMEs decreased with increasing carbon chain length. For unsaturated FAMEs, biodegradation rates increased with increasing number of double bonds. The presence of petrodiesel had a greater effect on the rate of biodegradation of biodiesel than on the extent of removal. PMID:27448319

  14. Summary report on the aerobic degradation of diesel fuel and the degradation of toluene under aerobic, denitrifying and sulfate reducing conditions

    SciTech Connect

    Coyne, P.; Smith, G.

    1995-08-15

    This report contains a number of studies that were performed to better understand the technology of the biodegradation of petroleum hydrocarbons. Topics of investigation include the following: diesel fuel degradation by Rhodococcus erythropolis; BTEX degradation by soil isolates; aerobic degradation of diesel fuel-respirometry; aerobic degradation of diesel fuel-shake culture; aerobic toluene degradation by A3; effect of HEPES, B1, and myo-inositol addition on the growth of A3; aerobic and anaerobic toluene degradation by contaminated soils; denitrifying bacteria MPNs; sulfate-reducing bacteria MPNs; and aerobic, DNB and SRB enrichments.

  15. Genome sequence of the model sulfate reducer Desulfovibrio gigas: a comparative analysis within the Desulfovibrio genus*

    PubMed Central

    Morais-Silva, Fabio O; Rezende, Antonio Mauro; Pimentel, Catarina; Santos, Catia I; Clemente, Carla; Varela–Raposo, Ana; Resende, Daniela M; da Silva, Sofia M; de Oliveira, Luciana Márcia; Matos, Marcia; Costa, Daniela A; Flores, Orfeu; Ruiz, Jerónimo C; Rodrigues-Pousada, Claudina

    2014-01-01

    Desulfovibrio gigas is a model organism of sulfate-reducing bacteria of which energy metabolism and stress response have been extensively studied. The complete genomic context of this organism was however, not yet available. The sequencing of the D. gigas genome provides insights into the integrated network of energy conserving complexes and structures present in this bacterium. Comparison with genomes of other Desulfovibrio spp. reveals the presence of two different CRISPR/Cas systems in D. gigas. Phylogenetic analysis using conserved protein sequences (encoded by rpoB and gyrB) indicates two main groups of Desulfovibrio spp, being D. gigas more closely related to D. vulgaris and D. desulfuricans strains. Gene duplications were found such as those encoding fumarate reductase, formate dehydrogenase, and superoxide dismutase. Complexes not yet described within Desulfovibrio genus were identified: Mnh complex, a v-type ATP-synthase as well as genes encoding the MinCDE system that could be responsible for the larger size of D. gigas when compared to other members of the genus. A low number of hydrogenases and the absence of the codh/acs and pfl genes, both present in D. vulgaris strains, indicate that intermediate cycling mechanisms may contribute substantially less to the energy gain in D. gigas compared to other Desulfovibrio spp. This might be compensated by the presence of other unique genomic arrangements of complexes such as the Rnf and the Hdr/Flox, or by the presence of NAD(P)H related complexes, like the Nuo, NfnAB or Mnh. PMID:25055974

  16. DMSP: tetrahydrofolate methyltransferase from the marine sulfate-reducing bacterium strain WN

    NASA Astrophysics Data System (ADS)

    Jansen, M.; Hansen, T. A.

    2000-08-01

    Dimethylsulfoniopropionate (DMSP), an important compatible solute of many marine algae, can be metabolised by bacteria via cleavage to dimethylsulfide and acrylate or via an initial demethylation. This is the first report on the purification of an enzyme that specifically catalyses the demethylation of DMSP. The enzyme was isolated from the sulfate-reducing bacterium strain WN, which grows on DMSP and demethylates it to methylthiopropionate. DMSP:tetrahydrofolate (THF) methyltransferase from strain WN was purified 76-fold [to a specific activity of 40.5 μmol min -1 (mg protein) -1]. SDS polyacrylamide gel electrophoresis showed two bands of approximately 10 and 35 kDa; in particular the 35 kDa polypeptide became significantly enriched during the purification. Storage of the purified fraction at -20°C under nitrogen resulted in a 99% loss of activity in two days. The activity could be partially restored by addition of 200 μM cyanocobalamin, hydroxocobalamin or coenzyme B 12. ATP did not have any positive effect on activity. Reduction of the assay mixture by titanium(III)nitrilotriacetic acid slightly stimulated the activity. Gel filtration chromatography revealed a native molecular mass between 45 and 60 kDa for the DMSP:THF methyltransferase. The enzyme was most active at 35°C and pH 7.8. Glycine betaine, which can be considered an N-containing structural analogue of DMSP, did not serve as a methyl donor for DMSP:THF methyltransferase. Various sulfur-containing DMSP-analogues were tested but only methylethylsulfoniopropionate served as methyl donor. None of these compounds inhibited methyl transfer from DMSP to THF. Strain WN did not grow on any of the sulfur-containing DMSP-analogues.

  17. The Use of Seaweed and Sugarcane Bagasse for the Biological Treatment of Metal-contaminated Waters Under Sulfate-reducing Conditions

    NASA Astrophysics Data System (ADS)

    Gonçalves, Márcia Monteiro Machado; de Mello, Luiz Antonio Oliveira; da Costa, Antonio Carlos Augusto

    When wetlands reach maximum treatment capacity to remove heavy metals, removal can still take place through precipitation as sulfide because of the biological reduction of sulfate. To achieve this goal, anaerobic conditions must be attained, a sulfate source must exist, and an adequate substrate for sulfate-reducing bacteria (SRB) is also required. In the present work, two ligneous-cellulosic materials, a brown seaweed and sugarcane bagasse, have been selected as substrates for SRB growth. Experiments were simultaneously conducted in continuous operation in two columns (0.57 L each), one containing the ligneous-cellulosic material plus inoculum and another containing only the ligneous-cellulosic material. In this work, the removal of cadmium and zinc was studied because of their presence in effluents from mining/metallurgy operations. Results obtained indicated that the inoculated reactor was able to treat the effluent more efficiently than the noninoculated reactor considering the time course of the tests.

  18. Characterization of a new thermophilic sulfate-reducing bacterium Thermodesulfovibrio yellowstonii, gen. nov. and sp. nov.: its phylogenetic relationship to Thermodesulfobacterium commune and their origins deep within the bacterial domain

    NASA Technical Reports Server (NTRS)

    Henry, E. A.; Devereux, R.; Maki, J. S.; Gilmour, C. C.; Woese, C. R.; Mandelco, L.; Schauder, R.; Remsen, C. C.; Mitchell, R.

    1994-01-01

    A thermophilic sulfate-reducing vibrio isolated from thermal vent water in Yellowstone Lake, Wyoming, USA is described. The gram-negative, curved rod-shaped cells averaged 0.3 micrometer wide and 1.5 micrometers long. They were motile by means of a single polar flagellum. Growth was observed between 40 degrees and 70 degrees C with optimal growth at 65 degrees C. Cultures remained viable for one year at 27 degrees C although spore-formation was not observed. Sulfate, thiosulfate and sulfite were used as electron acceptors. Sulfur, fumarate and nitrate were not reduced. In the presence of sulfate, growth was observed only with lactate, pyruvate, hydrogen plus acetate, or formate plus acetate. Pyruvate was the only compound observed to support fermentative growth. Pyruvate and lactate were oxidized to acetate. Desulfofuscidin and c-type cytochromes were present. The G + C content was 29.5 mol%. The divergence in the 16 S ribosomal RNA sequences between the new isolate and Thermodesulfobacterium commune suggests that these two thermophilic sulfate-reducing bacteria represent different genera. These two bacteria depict a lineage that branches deeply within the Bacteria domain and which is clearly distinct from previously defined phylogenetic lines of sulfate-reducing bacteria. Strain YP87 is described as the type strain of the new genus and species Thermodesulfovibrio yellowstonii.

  19. Septage treatments to reduce the numbers of bacteria and polioviruses.

    PubMed Central

    Stramer, S L; Cliver, D O

    1984-01-01

    Disposal of the pumped contents of septic tanks (septage) represents a possible means of dissemination of enteric pathogens including viruses, since persistence of enteroviruses in septic tank sludge for greater than 100 days has been demonstrated. The risk of exposure to potentially infectious agents can be reduced by disinfecting septages before their disposal. Of the septage disinfectants examined (technical and analytical grade glutaraldehyde, hydrogen peroxide, heat treatments, and a combination of heat and hydrogen peroxide), the treatment including hydrogen peroxide (5 mg, plus 0.33 mg of trichloroacetic acid, per ml of septage) and 55 degrees C killed virtually all the bacteria in septage within 1 h, whereas 55 degrees C alone inactivated inoculated polioviruses within 30 min. Virus was the most sensitive to heat, whereas fecal coliforms appeared to be the most sensitive to all chemical treatments. The responses of fecal streptococci and virus to both grades of glutaraldehyde (each at 1 mg/ml) were similar. Virus was more resistant than either fecal streptococci or total bacteria to low concentrations of hydrogen peroxide (1 to 5 mg/ml); however, virus and fecal streptococci were more labile than total bacteria to the highest peroxide concentration (10 mg/ml) examined. It is possible that the treatment combining heat and hydrogen peroxide was the most effective in reducing the concentrations of all bacteria, because catalase and peroxidases as well as other enzymes were heat inactivated, although catalase seems the most likely cause of damage. However, this most effective treatment does not appear to be practical for on-site use as performed, so further work on septage disinfection is recommended. PMID:6093691

  20. Microbial Activity In The Peerless Jenny King Sulfate Reducing Bioreactor System (Presentation)

    EPA Science Inventory

    The Peerless Jenny King treatment system is a series of four sulfate reducing bioreactor cells installed to treat acid mine drainage in the Upper Tenmile Creek Superfund Site located in the Rimini Mining District, near Helena MT. The system consists of a wetland pretreatment fol...

  1. Seasonal composition and activity of sulfate-reducing prokaryotic communities in seagrass bed sediments

    EPA Science Inventory

    Sulfate-reducing prokaryotes (SRP) play a key role in the carbon and nutrient cycles of coastal marine, vegetated ecosystems, but the interactions of SRP communities with aquatic plants remain little studied. The abundance, activity, and community composition of SRP was studied i...

  2. Microbial Activity In The Peerless Jenny King Sulfate Reducing Bioreactors System

    EPA Science Inventory

    The Peerless Jenny King treatment system is a series of four sulfate reducing bioreactor cells installed to treat acid mine drainage in the Upper Tenmile Creek Superfund Site located in the Rimini Mining District, near Helena, MT. The system consists of a wetland pretreatment fo...

  3. Genome Sequence of the Acidophilic Sulfate-Reducing Peptococcaceae Strain CEB3

    PubMed Central

    Petzsch, Patrick; Poehlein, Anja; Johnson, D. Barrie; Daniel, Rolf; Schlömann, Michael

    2015-01-01

    We report the draft genome of the Peptococcaceae strain CEB3 that originated from an acidic (pH 2.5) stream draining an abandoned copper mine. Strain CEB3 is one of the very few reported acidophilic sulfate-reducing isolates. The 5.04-Mb draft genome harbors 5,069 predicted protein-encoding and 66 RNA genes. PMID:26251503

  4. Temperature and its control of isotope fractionation by a sulfate-reducing bacterium

    NASA Astrophysics Data System (ADS)

    Canfield, Donald E.; Olesen, Claus A.; Cox, Raymond P.

    2006-02-01

    A synthesis of previous results, which we dub the "standard model," provides a prediction as to how isotope fractionation during sulfate reduction should respond to physiological variables such as specific rate of sulfate reduction and environmental variables such as substrate availability and temperature. The standard model suggests that isotope fractionation should decrease with increasing specific rates of sulfate reduction (rate per cell). Furthermore, the standard model predicts that low fractionations should be found at both high and low temperatures whereas the highest fractionations should be found in the intermediate temperature range. These fractionation trends are controlled, as a function of temperature, by the balance between the transfer rates of sulfate into and out of the cell and the exchange between the sulfur pools internal to the organism. We test this standard model by conducting experiments on the growth physiology and isotope fractionation, as a function of temperature, by the sulfate-reducing bacterium Desulfovibrio desulfuricans (DSMZ 642). Our results contrast with the "standard model" by showing a positive correlation between specific rates of sulfate reduction and fractionation. Also by contrast with the standard model, we found the highest fractionations at low and high temperatures and the lowest fractionations in the intermediate temperature range. We develop a fractionation model which can be used to explain both our results as well as the results of the "standard model." Differences in fractionation with temperature relate to differences in the specific temperature response of internal enzyme kinetics as well as the exchange rates of sulfate in and out of the cell. It is expected that the kinetics of these processes will show strain-specific differences.

  5. Modification of Lignins by Growing Cells of the Sulfate-Reducing Anaerobe Desulfovibrio desulfuricans†

    PubMed Central

    Ziomek, E.; Williams, R. E.

    1989-01-01

    The anaerobic sulfate-reducing bacterium Desulfovibrio desulfuricans was grown on medium supplemented with either Kraft lignin or lignosulfonate. Only lignosulfonate contributed to the growth of D. desulfuricans cells, by replacing sulfate, a natural electron acceptor for this microorganism. Kraft lignin added to the culture medium could not substitute for lactate or sulfate, both necessary culture medium components. However, it was found to enhance the viability of D. desulfuricans cells. When changes occurring in lignin during growth of Desulfovibrio cultures were monitored, it was found that both lignin preparations could be partially depolymerized. Spectrophotometric and elemental analysis of biologically treated lignins suggested that both the polyphenolic backbone and lignin functional groups were affected by D. desulfuricans. After treatment, a twofold increase in the sulfur content of Kraft lignin and a minor decrease (14%) in the sulfur content of lignosulfonate were observed. After biological treatment, Kraft lignin and lignosulfonate both bound larger quantities of heavy metals. PMID:16348007

  6. Monofluorophosphate is a selective inhibitor of respiratory sulfate-reducing microorganisms.

    PubMed

    Carlson, Hans K; Stoeva, Magdalena K; Justice, Nicholas B; Sczesnak, Andrew; Mullan, Mark R; Mosqueda, Lorraine A; Kuehl, Jennifer V; Deutschbauer, Adam M; Arkin, Adam P; Coates, John D

    2015-03-17

    Despite the environmental and economic cost of microbial sulfidogenesis in industrial operations, few compounds are known as selective inhibitors of respiratory sulfate reducing microorganisms (SRM), and no study has systematically and quantitatively evaluated the selectivity and potency of SRM inhibitors. Using general, high-throughput assays to quantitatively evaluate inhibitor potency and selectivity in a model sulfate-reducing microbial ecosystem as well as inhibitor specificity for the sulfate reduction pathway in a model SRM, we screened a panel of inorganic oxyanions. We identified several SRM selective inhibitors including selenate, selenite, tellurate, tellurite, nitrate, nitrite, perchlorate, chlorate, monofluorophosphate, vanadate, molydate, and tungstate. Monofluorophosphate (MFP) was not known previously as a selective SRM inhibitor, but has promising characteristics including low toxicity to eukaryotic organisms, high stability at circumneutral pH, utility as an abiotic corrosion inhibitor, and low cost. MFP remains a potent inhibitor of SRM growing by fermentation, and MFP is tolerated by nitrate and perchlorate reducing microorganisms. For SRM inhibition, MFP is synergistic with nitrite and chlorite, and could enhance the efficacy of nitrate or perchlorate treatments. Finally, MFP inhibition is multifaceted. Both inhibition of the central sulfate reduction pathway and release of cytoplasmic fluoride ion are implicated in the mechanism of MFP toxicity. PMID:25698072

  7. Reduction of uranium(VI) under sulfate-reducing conditions in the presence of Fe(III)-(hydr)oxides

    NASA Astrophysics Data System (ADS)

    Sani, R. K.; Peyton, B. M.; Amonette, J. E.; Geesey, G. G.

    2004-06-01

    Hexavalent uranium [U(VI)] dissolved in a modified lactate-C medium was treated under anoxic conditions with a mixture of an Fe(III)-(hydr)oxide mineral (hematite, goethite, or ferrihydrite) and quartz. The mass of Fe(III)-(hydr)oxide mineral was varied to give equivalent Fe(III)-mineral surface areas. After equilibration, the U(VI)-mineral suspensions were inoculated with sulfate-reducing bacteria, Desulfovibrio desulfuricans G20. Inoculation of the suspensions containing sulfate-limited medium yielded significant G20 growth, along with concomitant reduction of sulfate and U(VI) from solution. With lactate-limited medium, however, some of the uranium that had been removed from solution was resolubilized in the hematite treatments and, to a lesser extent, in the goethite treatments, once the lactate was depleted. No resolubilization was observed in the lactate-limited ferrihydrite treatment even after a prolonged incubation of 4 months. Uranium resolubilization was attributed to reoxidation of the uraninite by Fe(III) present in the (hydr)oxide phases. Analysis by U L 3-edge XANES spectroscopy of mineral specimens sampled at the end of the experiments yielded spectra similar to that of uraninite, but having distinct features, notably a much more intense and slightly broader white line consistent with precipitation of nanometer-sized particles. The XANES spectra thus provided strong evidence for SRB-promoted removal of U(VI) from solution by reductive precipitation of uraninite. Consequently, our results suggest that SRB mediate reduction of soluble U(VI) to an insoluble U(IV) oxide, so long as a suitable electron donor is available. Depletion of the electron donor may result in partial reoxidation of the U(IV) to soluble U(VI) species when the surfaces of crystalline Fe(III)-(hydr)oxides are incompletely reduced.

  8. Physicochemical and biological characterization of long-term operated sulfate reducing granular sludge in the SANI® process.

    PubMed

    Hao, Tianwei; Luo, Jinghai; Wei, Li; Mackey, Hamish R; Liu, Rulong; Rey Morito, Guillermo; Chen, Guang-Hao

    2015-03-15

    The SANI(®) process (Sulfate reduction, Autotrophic denitrification and Nitrification Integrated) is a treatment system with low energy demands. The major bioreactor of this new technology is a sulfate-reducing up-flow sludge bed (SRUSB) that converts organics and provides electron donors for subsequent autotrophic denitrification. This research characterizes the granules inside the SRUSB, with the aim of improving its efficiency, maximizing its operational flexibility, and minimizing its footprint. The unique sulfate-reducing bacteria (SRB) granules serving in the SRUSB were found to increase the resilience and compactness of the SRUSB. The granules, with a compact and porous structure, showed high cohesion resisting breakage with a shear force G > 3400 s(-1). The hydrophobicity of the external surface of the mature granules remained stable at around 70% and acid volatile sulfide (AVS) accumulated at the bottom of the SRUSB. 16s rRNA gene analysis of the microbial communities revealed that Desulfobulbus (42.1%), Prosthecochloris (19%) and Trichococcus (12%) dominated the mature granular sludge. Fluorescence in situ hybridization (FISH) further showed that SRB organisms were located internally and then surrounded by non-SRB. According to the FISH results, the spatial distribution of extracellular polymeric substances (EPS) displayed protein and α-polysaccharides in the exterior and β-polysaccharide in the core of the granules. Such biological structure suggests that each SRB granule acts as an efficient and independent unit, capable of achieving both fermentation and organic conversion. The present investigation sheds light on the physicochemical and biological characteristics of the SRB granulate. This information provides valuable information for scaling-up the SANI(®) process to treat real saline sewage in Hong Kong. PMID:25600299

  9. Hydrogen-fed biofilm reactors reducing selenate and sulfate: Community structure and capture of elemental selenium within the biofilm.

    PubMed

    Ontiveros-Valencia, Aura; Penton, Christopher R; Krajmalnik-Brown, Rosa; Rittmann, Bruce E

    2016-08-01

    Remediation of selenate (SeO4 (2-) ) contamination through microbial reduction is often challenging due to the presence of sulfate (SO4 (2-) ), which can lead to competition for the electron donor and the co-production of toxic H2 S. Microbial reduction of SeO4 (2-) in the presence of SO4 (2-) was studied in two hydrogen-based membrane biofilm reactors (MBfRs). One MBfR was initiated with SO4 (2-) -reducing conditions and gradually shifted to SeO4 (2-) reduction. The second MBfR was developed with a SeO4 (2-) -reducing biofilm, followed by SO4 (2-) introduction. Biofilms within both MBfRs achieved greater than 90% SeO4 (2-) reduction, even though the SeO4 (2-) concentration ranged from 1,000-11,000 μg/L, more than 20-200 times the maximum contaminant level for drinking water (50 μg/L). Biofilm microbial community composition, assessed by 16S rRNA gene-based amplicon pyrosequencing, was distinct between the two MBfRs and was framed by alterations in SeO4 (2-) loading. Specifically, high SeO4 (2-) loading resulted in communities mainly composed of denitrifying bacteria (e.g., Denitratisoma and Dechloromonas). In contrast, low loading led to mostly sulfate-reducing bacteria (i.e., Desulfovibrio) and sulfur-oxidizing bacteria (i.e., Sulfuricurvum and Sulfurovum). SeO4 (2-) was reduced to elemental selenium (Se°), which was visualized within the biofilm as crystalloid aggregates, with its fate corresponding to that of biofilm solids. In conclusion, microbial biofilm communities initiated under either SeO4 (2-) or SO4 (2-) -reducing conditions attained high SeO4 (2-) removal rates even though their microbial community composition was quite distinct. Biotechnol. Bioeng. 2016;113: 1736-1744. © 2016 Wiley Periodicals, Inc. PMID:26804665

  10. Characterization of the cytochrome system of a nitrogen-fixing strain of a sulfate-reducing bacterium: Desulfovibrio desulfuricans strain Berre-Eau.

    PubMed

    Moura, I; Fauque, G; LeGall, J; Xavier, A V; Moura, J J

    1987-02-01

    Two c-type cytochromes were purified and characterized by electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopic techniques, from the sulfate-reducer nitrogen-fixing organism, Desulfovibrio desulfuricans strain Berre-Eau (NCIB 8387). The purification procedures included several chromatographic steps on alumina, carboxymethylcellulose and gel filtration. A tetrahaem and a monohaem cytochrome were identified. The multihaem cytochrome has visible, EPR and NMR spectra with general properties similar to other low-potential bis-histidinyl axially bound haem proteins, belonging to the class of tetrahaem cytochrome c3 isolated from other Desulfovibrio species. The monohaem cytochrome c553 is ascorbate-reducible and its EPR and NMR data are characteristic of a cytochrome with methionine-histidine ligation. Their properties are compared with other homologous proteins isolated from sulfate-reducing bacteria. PMID:3030740

  11. Metal removal and sulfate reduction in low-sulfate mine drainage

    SciTech Connect

    Farmer, G.H.; Updegraff, D.M.; Radehaus, P.M.; Bates, E.R.

    1995-12-31

    A treatability study using two continuous upflow bioreactors was conducted to evaluate the potential removal of metal contamination, primarily zinc, from mine drainage with constructed wetlands that incorporate sulfate-reducing bacteria (SRB). The drainage from the Burleigh Tunnel in Silver Plume, Colorado, contains low levels of sulfate that may limit the production of hydrogen sulfide by sulfate-reducing bacteria, thus limiting metal removal by the system. Total metals, anions, and field parameters in the mine drainage and the bioreactor effluents were routinely analyzed over 8 weeks. In addition, the bioreactor compost packing was analyzed for metals and sulfate-reducing bacteria. Zinc removal in both reactors was in excess of 99% after 8 weeks of operation. Furthermore, sulfate-reducing bacteria in the bioreactor compost ranged from 10{sup 5} to 10{sup 6} colony-forming units per gram of compost.

  12. Sulfur Isotope Fractionation during the Evolutionary Adaptation of a Sulfate-Reducing Bacterium

    PubMed Central

    Anderson-Trocmé, Luke; Whyte, Lyle G.; Zane, Grant M.; Wall, Judy D.; Wing, Boswell A.

    2015-01-01

    Dissimilatory sulfate reduction is a microbial catabolic pathway that preferentially processes less massive sulfur isotopes relative to their heavier counterparts. This sulfur isotope fractionation is recorded in ancient sedimentary rocks and generally is considered to reflect a phenotypic response to environmental variations rather than to evolutionary adaptation. Modern sulfate-reducing microorganisms isolated from similar environments can exhibit a wide range of sulfur isotope fractionations, suggesting that adaptive processes influence the sulfur isotope phenotype. To date, the relationship between evolutionary adaptation and isotopic phenotypes has not been explored. We addressed this by studying the covariation of fitness, sulfur isotope fractionation, and growth characteristics in Desulfovibrio vulgaris Hildenborough in a microbial evolution experiment. After 560 generations, the mean fitness of the evolved lineages relative to the starting isogenic population had increased by ∼17%. After 927 generations, the mean fitness relative to the initial ancestral population had increased by ∼20%. Growth rate in exponential phase increased during the course of the experiment, suggesting that this was a primary influence behind the fitness increases. Consistent changes were observed within different selection intervals between fractionation and fitness. Fitness changes were associated with changes in exponential growth rate but changes in fractionation were not. Instead, they appeared to be a response to changes in the parameters that govern growth rate: yield and cell-specific sulfate respiration rate. We hypothesize that cell-specific sulfate respiration rate, in particular, provides a bridge that allows physiological controls on fractionation to cross over to the adaptive realm. PMID:25662968

  13. Sulfur isotope fractionation during the evolutionary adaptation of a sulfate-reducing bacterium.

    PubMed

    Pellerin, André; Anderson-Trocmé, Luke; Whyte, Lyle G; Zane, Grant M; Wall, Judy D; Wing, Boswell A

    2015-04-01

    Dissimilatory sulfate reduction is a microbial catabolic pathway that preferentially processes less massive sulfur isotopes relative to their heavier counterparts. This sulfur isotope fractionation is recorded in ancient sedimentary rocks and generally is considered to reflect a phenotypic response to environmental variations rather than to evolutionary adaptation. Modern sulfate-reducing microorganisms isolated from similar environments can exhibit a wide range of sulfur isotope fractionations, suggesting that adaptive processes influence the sulfur isotope phenotype. To date, the relationship between evolutionary adaptation and isotopic phenotypes has not been explored. We addressed this by studying the covariation of fitness, sulfur isotope fractionation, and growth characteristics in Desulfovibrio vulgaris Hildenborough in a microbial evolution experiment. After 560 generations, the mean fitness of the evolved lineages relative to the starting isogenic population had increased by ∼ 17%. After 927 generations, the mean fitness relative to the initial ancestral population had increased by ∼ 20%. Growth rate in exponential phase increased during the course of the experiment, suggesting that this was a primary influence behind the fitness increases. Consistent changes were observed within different selection intervals between fractionation and fitness. Fitness changes were associated with changes in exponential growth rate but changes in fractionation were not. Instead, they appeared to be a response to changes in the parameters that govern growth rate: yield and cell-specific sulfate respiration rate. We hypothesize that cell-specific sulfate respiration rate, in particular, provides a bridge that allows physiological controls on fractionation to cross over to the adaptive realm. PMID:25662968

  14. Examining Deep Subsurface Sulfate Reducing Bacterial Diversity to Test Spatial and Temporal Biogeography

    NASA Astrophysics Data System (ADS)

    Mills, H. J.; Reese, B. K.

    2013-12-01

    In this study, we take advantage of the isolation and scale of the deep marine subsurface to examine microbial biogeography. Unlike other environments, deep marine subsurface provides a unique opportunity to study biogeography across four dimensions. These samples are not only isolated by linear space on a global scale, but they are also temporally isolated by, in some cases, tens of millions of years. Through the support of multiple Integrated Ocean Drilling Program expeditions, we characterized the metabolically active fraction of the subsurface microbial community by targeting and sequencing 16S rRNA gene transcripts (RNA-based analysis). By characterizing the metabolically active fraction, we described lineages that were currently under selective environmental pressure and not relic lineages that may have become dormant or dead at some point in the past. This study was narrowed from the total diversity obtained to provide a detailed examination of the distribution and diversity of sulfate reducing bacteria (SRB); a functional group highly important to and ubiquitous in marine systems. The biogeochemical importance of this functional group, compounded with defined clades makes it a valuable and feasible target for a global biogeography study. SRB lineages from the deep subsurface were compared to contemporary lineages collected from multiple shallow sediment sites that had been extracted and sequenced using the same techniques. The SRB sequences acquired from our databases were clustered using 97% sequence similarity and analyzed using a suite of diversity and statistical tools. The geochemical conditions of the sediments sampled were considered when analyzing the resulting dendrograms and datasets. As hypothesized, lineages from the deep subsurface phylogenetically grouped together. However, similarities were detected to lineages from the shallow modern sediments, suggesting novel lineages may have evolved at a slow rate due to predicted lengthened life cycles

  15. Penetration of sulfate reducers through a porous North Sea oil reservoir

    SciTech Connect

    Beeder, J.; Nilsen, R.K.; Thorstenson, T.; Torsvik, T.

    1996-09-01

    During offshore oil production, seawater is often injected into the reservoir to maintain pressure. Sulfate reducers have been reported from water samples in Norwegian oil fields. However in order to demonstrate penetration, a suitable indicator microorganism is required. This paper reports the isolation of one such indicator bacterium from injection water followed by isolation of the same bacterium from water from oil field production system. 28 refs., 1 fig., 2 tabs.

  16. The ecology and biotechnology of sulphate-reducing bacteria.

    PubMed

    Muyzer, Gerard; Stams, Alfons J M

    2008-06-01

    Sulphate-reducing bacteria (SRB) are anaerobic microorganisms that use sulphate as a terminal electron acceptor in, for example, the degradation of organic compounds. They are ubiquitous in anoxic habitats, where they have an important role in both the sulphur and carbon cycles. SRB can cause a serious problem for industries, such as the offshore oil industry, because of the production of sulphide, which is highly reactive, corrosive and toxic. However, these organisms can also be beneficial by removing sulphate and heavy metals from waste streams. Although SRB have been studied for more than a century, it is only with the recent emergence of new molecular biological and genomic techniques that we have begun to obtain detailed information on their way of life. PMID:18461075

  17. Sulfato/thiosulfato reducing bacteria characterization by FT-IR spectroscopy: a new approach to biocorrosion control.

    PubMed

    Rubio, Celine; Ott, Christelle; Amiel, Caroline; Dupont-Moral, Isabelle; Travert, Josette; Mariey, Laurence

    2006-03-01

    Sulfato and Thiosulfato Reducing Bacteria (SRB, TRB) can induce corrosion process on steel immersed in seawater. This phenomenon, called biocorrosion, costs approximatively 5 billion euros in France each year. We provide the first evidence that Fourier Transformed InfraRed (FTIR) spectroscopy is a competitive technique to evaluate the sulfurogen flora involved in biocorrosion in comparison with time consuming classical identification methods or PCR analyses. A great discrimination was obtained between SRB, TRB and some contamination bacteria known to be present in seawater and seem to be able to reduce sulfate under particular conditions. Moreover, this preliminary study demonstrates that FTIR spectroscopic and genotypic results present a good correlation (these results are confirmed by other data obtained before or later, data not shown here). The advantages gained by FTIR spectroscopy are to give information on strain phenotype and bacterial metabolism which are of great importance in corrosion processes. PMID:16176842

  18. Sulfate-Reducing Microorganisms in Wetlands – Fameless Actors in Carbon Cycling and Climate Change

    PubMed Central

    Pester, Michael; Knorr, Klaus-Holger; Friedrich, Michael W.; Wagner, Michael; Loy, Alexander

    2012-01-01

    Freshwater wetlands are a major source of the greenhouse gas methane but at the same time can function as carbon sink. Their response to global warming and environmental pollution is one of the largest unknowns in the upcoming decades to centuries. In this review, we highlight the role of sulfate-reducing microorganisms (SRM) in the intertwined element cycles of wetlands. Although regarded primarily as methanogenic environments, biogeochemical studies have revealed a previously hidden sulfur cycle in wetlands that can sustain rapid renewal of the small standing pools of sulfate. Thus, dissimilatory sulfate reduction, which frequently occurs at rates comparable to marine surface sediments, can contribute up to 36–50% to anaerobic carbon mineralization in these ecosystems. Since sulfate reduction is thermodynamically favored relative to fermentative processes and methanogenesis, it effectively decreases gross methane production thereby mitigating the flux of methane to the atmosphere. However, very little is known about wetland SRM. Molecular analyses using dsrAB [encoding subunit A and B of the dissimilatory (bi)sulfite reductase] as marker genes demonstrated that members of novel phylogenetic lineages, which are unrelated to recognized SRM, dominate dsrAB richness and, if tested, are also abundant among the dsrAB-containing wetland microbiota. These discoveries point toward the existence of so far unknown SRM that are an important part of the autochthonous wetland microbiota. In addition to these numerically dominant microorganisms, a recent stable isotope probing study of SRM in a German peatland indicated that rare biosphere members might be highly active in situ and have a considerable stake in wetland sulfate reduction. The hidden sulfur cycle in wetlands and the fact that wetland SRM are not well represented by described SRM species explains their so far neglected role as important actors in carbon cycling and climate change. PMID:22403575

  19. Halotolerant and Resistant to High pH Hydrogenase from Haloalkaliphilic Sulfate-Reducing Bacterium Desulfonatronum thiodismutans

    NASA Technical Reports Server (NTRS)

    Detkova, Ekaterina N.; Pikuta, Elena V.; Hoover, Richard B.

    2004-01-01

    Hydrogenase is the key enzyme of energetic metabolism in cells, it catalyzing the converse reaction of hydrogen oxidation and responsible for consumption and excretion of hydrogen in bacteria. Hydrogenases are proteins containing either Nickel and Iron, or the only Iron in theirs active center. Hydrogenases have been found in many microorganisms, such as Methanogenic, acetogenic, nitrogen-fixing, photosynthetic and sulfate-reducing bacteria that could utilize the hydrogen as energy source or use it as electron sink. Hydrogenases are subject for wide physiological, biochemical, physicochemical and genetic studies due to theirs abilities produce the molecular hydrogen as alternative source of pure energy. Notwithstanding on enough large quantity of works that deal with intracellular and extrasellular enzymes of halophilic bacteria, the data about hydrogenases and theirs functions of salts practically are absent. The study of hydrogenase in cell-free extracts of extremely halophilic eubacterium Acetohalobium mabaticum showed dramatic increasing activity of the enzyme at high concentrations of NaCl and KCI (close to saturated solution). Here we present the data of free-cells extracted hydrogenase from new haloalkaliphilic sulfate-reducing bacterium Desulfonatronum thiodismutans, which grow on highly miniralized carbonate-bicarbonate medium in salinity range 1 to 7 % and at pH 7.8 - 10.5. Studied enzyme was active in Concentration range from 0 to 4.3 M NaCl with optimum at 1.0 M NaCl. At 1.0 M NaCl the enzyme activity was increased on 20 %, but with changing concentration from 2.1 M to 3.4 M the activity decreased and was kept on constant level. NaHCO3 inhibited hydrogenase activity on more then 30 %. The maximum of enzyme activity was observed at pH 9.5 with limits 7.5 and 11.5 that practically equal to pH optimum of bacterial growth. Therefore the hydrogenase of Desulfanatronum thiodismutans is tolerant to high concentrations of sodium salts and it also resistant to

  20. Sulfur Isotope Enrichment during Maintenance Metabolism in the Thermophilic Sulfate-Reducing Bacterium Desulfotomaculum putei▿

    PubMed Central

    Davidson, Mark M.; Bisher, M. E.; Pratt, Lisa M.; Fong, Jon; Southam, Gordon; Pfiffner, Susan M.; Reches, Z.; Onstott, Tullis C.

    2009-01-01

    Values of Δ34S (\\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{pmc} \\usepackage[Euler]{upgreek} \\pagestyle{empty} \\oddsidemargin -1.0in \\begin{document} \\begin{equation*}={\\delta}^{34}S_{HS}-{\\delta}^{34}S_{SO_{4}}\\end{equation*}\\end{document}, where δ34SHS and \\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{pmc} \\usepackage[Euler]{upgreek} \\pagestyle{empty} \\oddsidemargin -1.0in \\begin{document} \\begin{equation*}{\\delta}^{34}S_{SO_{4}}\\end{equation*}\\end{document} indicate the differences in the isotopic compositions of the HS− and SO42− in the eluent, respectively) for many modern marine sediments are in the range of −55 to −75‰, much greater than the −2 to −46‰ ɛ34S (kinetic isotope enrichment) values commonly observed for microbial sulfate reduction in laboratory batch culture and chemostat experiments. It has been proposed that at extremely low sulfate reduction rates under hypersulfidic conditions with a nonlimited supply of sulfate, isotopic enrichment in laboratory culture experiments should increase to the levels recorded in nature. We examined the effect of extremely low sulfate reduction rates and electron donor limitation on S isotope fractionation by culturing a thermophilic, sulfate-reducing bacterium, Desulfotomaculum putei, in a biomass-recycling culture vessel, or “retentostat.” The cell-specific rate of sulfate reduction and the specific growth rate decreased progressively from the exponential phase to the maintenance phase, yielding average maintenance coefficients of 10−16 to 10−18 mol of SO4 cell−1 h−1 toward the end of the experiments. Overall S mass and isotopic balance were conserved during the experiment. The differences in the δ34S

  1. A novel biological sulfate reduction method using hydrogenogenic carboxydotrophic mesophilic bacteria.

    PubMed

    Sinharoy, Arindam; Manikandan, N Arul; Pakshirajan, Kannan

    2015-09-01

    Sulfate reduction by carbon monoxide (CO) utilizing anaerobic biomass from a large scale upflow anaerobic sludge blanket reactor was studied. Anaerobic mixed microbial consortia from five different sources were initially examined for their biological CO conversion potential. Among the different biomass, the biomass from an upflow anaerobic sludge blanket reactor treating domestic wastewater, located in Kavoor, Karnataka, India, showed a maximum CO conversion efficiency. The effect of three main culture parameters, i.e. inoculum volume, initial CO concentration and temperature on simultaneous CO conversion and sulfate reduction was assessed employing the Taguchi experimental design technique. A maximum CO conversion of 85.62% and a maximum sulfate reduction of 50.65% were achieved. Furthermore, the experimental data was fitted to substrate inhibition models reported in the literature. Among the different models, Monods and Haldane kinetic models were found most suitable to describe the kinetics of biomass growth and CO removal by the anaerobic biomass. PMID:26081625

  2. Extremophilic iron-reducing bacteria: Their implications for possible life in extraterrestrial environments

    SciTech Connect

    Zhou, J.; Liu, S.V.; Zhang, C.; Palumbo, A.V.; Phelps, T.J.

    1998-06-01

    Iron reduction is believed to be an early form of respiration and iron-reducing bacteria might have evolved very early on Earth. To support this hypothesis, the authors began to search for both thermophilic and psychrophilic iron-reducing bacteria because iron-reducing capacity may be a widely distributed trait if ancestral microorganisms include extremophilic iron-reducing bacteria. To date, they have obtained thermophilic Fe(III)-reducing and magnetite-forming enrichment cultures from geologically and hydrologically isolated, millions of years-old deep terrestrial subsurface samples. Three dominant bacteria were identified based on 16S ribosomal RNA gene sequences. Phylogenetical analysis indicated that these bacteria were closely related to Thermoanaerobacter ethanoliticus. Two pure thermophilic iron-reducing bacteria have been isolated and characterized from these enrichments, they also are able to degrade cellulose and xylan. Geological evidence indicated that these bacteria were separated from modern organisms for about 200 million years, and they are the oldest isolated bacteria available now. Evolutionary sequence analysis showed that the 16S rRNA genes evolved extremely slowly in these bacteria. In addition, the authors have obtained about 30 psychrophilic iron-reducing bacteria in samples from Siberia and Alaska permafrost soils, Pacific marine sediments and Hawaii deep sea water. These bacteria were also able to reduce other heavy metals. The isolation of both thermophilic and psychrophilic iron-reducing bacteria from surface and subsurface environments has significant implications for microbial evolution and for studying the origin of life in extraterrestrial environments.

  3. Microbial methanogenesis in the sulfate-reducing zone of surface sediments traversing the Peruvian margin

    NASA Astrophysics Data System (ADS)

    Maltby, J.; Sommer, S.; Dale, A. W.; Treude, T.

    2016-01-01

    We studied the concurrence of methanogenesis and sulfate reduction in surface sediments (0-25 cm below sea floor) at six stations (70, 145, 253, 407, 990 and 1024 m) along the Peruvian margin (12° S). This oceanographic region is characterized by high carbon export to the seafloor creating an extensive oxygen minimum zone (OMZ) on the shelf, both factors that could favor surface methanogenesis. Sediments sampled along the depth transect traversed areas of anoxic and oxic conditions in the bottom-near water. Net methane production (batch incubations) and sulfate reduction (35S-sulfate radiotracer incubation) were determined in the upper 0-25 cm b.s.f. of multiple cores from all stations, while deep hydrogenotrophic methanogenesis (> 30 cm b.s.f., 14C-bicarbonate radiotracer incubation) was determined in two gravity cores at selected sites (78 and 407 m). Furthermore, stimulation (methanol addition) and inhibition (molybdate addition) experiments were carried out to investigate the relationship between sulfate reduction and methanogenesis.

    Highest rates of methanogenesis and sulfate reduction in the surface sediments, integrated over 0-25 cm b.s.f., were observed on the shelf (70-253 m, 0.06-0.1 and 0.5-4.7 mmol m-2 d-1, respectively), while lowest rates were discovered at the deepest site (1024 m, 0.03 and 0.2 mmol m-2 d-1, respectively). The addition of methanol resulted in significantly higher surface methanogenesis activity, suggesting that the process was mostly based on non-competitive substrates - i.e., substrates not used by sulfate reducers. In the deeper sediment horizons, where competition was probably relieved due to the decrease of sulfate, the usage of competitive substrates was confirmed by the detection of hydrogenotrophic activity in the sulfate-depleted zone at the shallow shelf station (70 m).

    Surface methanogenesis appeared to be correlated to the availability of labile organic matter (C / N ratio) and organic carbon

  4. Microbial methanogenesis in the sulfate-reducing zone of surface sediments traversing the Peruvian margin

    NASA Astrophysics Data System (ADS)

    Maltby, J.; Sommer, S.; Dale, A. W.; Treude, T.

    2015-09-01

    We studied the concurrence of methanogenesis and sulfate reduction in surface sediments (0-25 cm below sea floor, cmbsf) at six stations (70, 145, 253, 407, 770 and 1024 m) along the Peruvian margin (12° S). This oceanographic region is characterized by high carbon export to the seafloor, creating an extensive oxygen minimum zone (OMZ) on the shelf, both factors that could favor surface methanogenesis. Sediments sampled along the depth transect traversed areas of anoxic and oxic conditions in the bottom-near water. Net methane production (batch incubations) and sulfate reduction (35S-sulfate radiotracer incubation) were determined in the upper 0-25 cmbsf of multicorer cores from all stations, while deep hydrogenotrophic methanogenesis (> 30 cmbsf, 14C-bicarbonate radiotracer incubation) was determined in two gravity cores at selected sites (78 and 407 m). Furthermore, stimulation (methanol addition) and inhibition (molybdate addition) experiments were carried out to investigate the relationship between sulfate reduction and methanogenesis. Highest rates of methanogenesis and sulfate reduction in the surface sediments, integrated over 0-25 cmbsf, were observed on the shelf (70-253 m, 0.06-0.1 and 0.5-4.7 mmol m-2 d-1, respectively), while lowest rates were discovered at the deepest site (1024 m, 0.03 and 0.2 mmol m-2 d-1, respectively). The addition of methanol resulted in significantly higher surface methanogenesis activity, suggesting that the process was mostly based on non-competitive substrates, i.e., substrates not used by sulfate reducers. In the deeper sediment horizons, where competition was probably relieved due to the decline of sulfate, the usage of competitive substrates was confirmed by the detection of hydrogenotrophic activity in the sulfate-depleted zone at the shallow shelf station (70 m). Surface methanogenesis appeared to be correlated to the availability of labile organic matter (C / N ratio) and organic carbon degradation (DIC production

  5. Disruption of Adenosine-5′-Phosphosulfate Kinase in Arabidopsis Reduces Levels of Sulfated Secondary Metabolites[W

    PubMed Central

    Mugford, Sarah G.; Yoshimoto, Naoko; Reichelt, Michael; Wirtz, Markus; Hill, Lionel; Mugford, Sam T.; Nakazato, Yoshimi; Noji, Masaaki; Takahashi, Hideki; Kramell, Robert; Gigolashvili, Tamara; Flügge, Ulf-Ingo; Wasternack, Claus; Gershenzon, Jonathan; Hell, Rüdiger; Saito, Kazuki; Kopriva, Stanislav

    2009-01-01

    Plants can metabolize sulfate by two pathways, which branch at the level of adenosine 5′-phosphosulfate (APS). APS can be reduced to sulfide and incorporated into Cys in the primary sulfate assimilation pathway or phosphorylated by APS kinase to 3′-phosphoadenosine 5′-phosphosulfate, which is the activated sulfate form for sulfation reactions. To assess to what extent APS kinase regulates accumulation of sulfated compounds, we analyzed the corresponding gene family in Arabidopsis thaliana. Analysis of T-DNA insertion knockout lines for each of the four isoforms did not reveal any phenotypical alterations. However, when all six combinations of double mutants were compared, the apk1 apk2 plants were significantly smaller than wild-type plants. The levels of glucosinolates, a major class of sulfated secondary metabolites, and the sulfated 12-hydroxyjasmonate were reduced approximately fivefold in apk1 apk2 plants. Although auxin levels were increased in the apk1 apk2 mutants, as is the case for most plants with compromised glucosinolate synthesis, typical high auxin phenotypes were not observed. The reduction in glucosinolates resulted in increased transcript levels for genes involved in glucosinolate biosynthesis and accumulation of desulfated precursors. It also led to great alterations in sulfur metabolism: the levels of sulfate and thiols increased in the apk1 apk2 plants. The data indicate that the APK1 and APK2 isoforms of APS kinase play a major role in the synthesis of secondary sulfated metabolites and are required for normal growth rates. PMID:19304933

  6. Isolation and characterization of a novel toluene-degrading, sulfate-reducing bacterium.

    PubMed Central

    Beller, H R; Spormann, A M; Sharma, P K; Cole, J R; Reinhard, M

    1996-01-01

    A novel sulfate-reducing bacterium isolated from fuel-contaminated subsurface soil, strain PRTOL1, mineralizes toluene as the sole electron donor and carbon source under strictly anaerobic conditions. The mineralization of 80% of toluene carbon to CO2 was demonstrated in experiments with [ring-U-14C]toluene; 15% of toluene carbon was converted to biomass and nonvolatile metabolic by-products, primarily the former. The observed stoichiometric ratio of moles of sulfate consumed per mole of toluene consumed was consistent with the theoretical ratio for mineralization of toluene coupled with the reduction of sulfate to hydrogen sulfide. Strain PRTOL1 also transforms o- and p-xylene to metabolic products when grown with toluene. However, xylene transformation by PRTOL1 is slow relative to toluene degradation and cannot be sustained over time. Stable isotope-labeled substrates were used in conjunction with gas chromatography-mass spectrometry to investigate the by-products of toluene and xylene metabolism. The predominant by-products from toluene, o-xylene, and p-xylene were benzylsuccinic acid, (2-methylbenzyl)succinic acid, and 4-methylbenzoic acid (or p-toluic acid), respectively. Metabolic by-products accounted for nearly all of the o-xylene consumed. Enzyme assays indicated that acetyl coenzyme A oxidation proceeded via the carbon monoxide dehydrogenase pathway. Compared with the only other reported toluene-degrading, sulfate-reducing bacterium, strain PRTOL1 is distinct in that it has a novel 16S rRNA gene sequence and was derived from a freshwater rather than marine environment. PMID:8919780

  7. In situ mobility of uranium in the presence of nitrate following sulfate-reducing conditions

    NASA Astrophysics Data System (ADS)

    Paradis, Charles J.; Jagadamma, Sindhu; Watson, David B.; McKay, Larry D.; Hazen, Terry C.; Park, Melora; Istok, Jonathan D.

    2016-04-01

    Reoxidation and mobilization of previously reduced and immobilized uranium by dissolved-phase oxidants poses a significant challenge for remediating uranium-contaminated groundwater. Preferential oxidation of reduced sulfur-bearing species, as opposed to reduced uranium-bearing species, has been demonstrated to limit the mobility of uranium at the laboratory scale yet field-scale investigations are lacking. In this study, the mobility of uranium in the presence of nitrate oxidant was investigated in a shallow groundwater system after establishing conditions conducive to uranium reduction and the formation of reduced sulfur-bearing species. A series of three injections of groundwater (200 L) containing U(VI) (5 μM) and amended with ethanol (40 mM) and sulfate (20 mM) were conducted in ten test wells in order to stimulate microbial-mediated reduction of uranium and the formation of reduced sulfur-bearing species. Simultaneous push-pull tests were then conducted in triplicate well clusters to investigate the mobility of U(VI) under three conditions: 1) high nitrate (120 mM), 2) high nitrate (120 mM) with ethanol (30 mM), and 3) low nitrate (2 mM) with ethanol (30 mM). Dilution-adjusted breakthrough curves of ethanol, nitrate, nitrite, sulfate, and U(VI) suggested that nitrate reduction was predominantly coupled to the oxidation of reduced-sulfur bearing species, as opposed to the reoxidation of U(IV), under all three conditions for the duration of the 36-day tests. The amount of sulfate, but not U(VI), recovered during the push-pull tests was substantially more than injected, relative to bromide tracer, under all three conditions and further suggested that reduced sulfur-bearing species were preferentially oxidized under nitrate-reducing conditions. However, some reoxidation of U(IV) was observed under nitrate-reducing conditions and in the absence of detectable nitrate and/or nitrite. This suggested that reduced sulfur-bearing species may not be fully effective at

  8. In situ mobility of uranium in the presence of nitrate following sulfate-reducing conditions.

    PubMed

    Paradis, Charles J; Jagadamma, Sindhu; Watson, David B; McKay, Larry D; Hazen, Terry C; Park, Melora; Istok, Jonathan D

    2016-04-01

    Reoxidation and mobilization of previously reduced and immobilized uranium by dissolved-phase oxidants poses a significant challenge for remediating uranium-contaminated groundwater. Preferential oxidation of reduced sulfur-bearing species, as opposed to reduced uranium-bearing species, has been demonstrated to limit the mobility of uranium at the laboratory scale yet field-scale investigations are lacking. In this study, the mobility of uranium in the presence of nitrate oxidant was investigated in a shallow groundwater system after establishing conditions conducive to uranium reduction and the formation of reduced sulfur-bearing species. A series of three injections of groundwater (200 L) containing U(VI) (5 μM) and amended with ethanol (40 mM) and sulfate (20 mM) were conducted in ten test wells in order to stimulate microbial-mediated reduction of uranium and the formation of reduced sulfur-bearing species. Simultaneous push-pull tests were then conducted in triplicate well clusters to investigate the mobility of U(VI) under three conditions: 1) high nitrate (120 mM), 2) high nitrate (120 mM) with ethanol (30 mM), and 3) low nitrate (2 mM) with ethanol (30 mM). Dilution-adjusted breakthrough curves of ethanol, nitrate, nitrite, sulfate, and U(VI) suggested that nitrate reduction was predominantly coupled to the oxidation of reduced-sulfur bearing species, as opposed to the reoxidation of U(IV), under all three conditions for the duration of the 36-day tests. The amount of sulfate, but not U(VI), recovered during the push-pull tests was substantially more than injected, relative to bromide tracer, under all three conditions and further suggested that reduced sulfur-bearing species were preferentially oxidized under nitrate-reducing conditions. However, some reoxidation of U(IV) was observed under nitrate-reducing conditions and in the absence of detectable nitrate and/or nitrite. This suggested that reduced sulfur-bearing species may not be fully effective at

  9. Factors Governing the Germination of Sulfate-Reducing Desulfotomaculum Endospores Involved in Oil Reservoir Souring.

    NASA Astrophysics Data System (ADS)

    Sherry, A.; Bell, E.; Cueto, G.; Suarez-Suarez, A.; Pilloni, G.; Hubert, C. R.

    2015-12-01

    Reservoir souring is caused by the activity of sulfate-reducing microorganisms (SRM) in subsurface oil reservoirs, and is often induced by seawater injection during secondary oil recovery. Souring can potentially contribute to corrosion of infrastructure, health and safety hazards to the workforce, and reduction in value by increasing refining costs associated with producing the oil resource. Souring causes annual losses in the billions of dollars to the oil industry. Endospore-forming SRM, such as Desulfotomaculum spp., are often suspected culprits in reservoir souring. Endospores can survive unfavourable conditions for long periods, yet remain poised to germinate and become active if conditions become more favourable. Factors governing endospore germination are poorly understood, but are thought to include availability of nutrients, possibly metabolic by products of other anaerobic bioprocesses, and/or variations in temperature. Most research has focused on aerobic Bacillus spp., with very few studies dedicated to spore germination among anaerobes (order Clostridiales) including the sulfate-reducing Desulfotomaculum found in anoxic subsurface petroleum reservoirs. For Desulfotomaculum spores in deep hot oil reservoirs, cold seawater introduction during secondary oil recovery may create thermal viability zones for sulfate reduction near the injection wellbore. To evaluate these processes, sulfate-containing microcosms were prepared with different marine sediments as a source of spores, and amended with organic substrates in the presence or absence of oil. Incubation at 80°C for six days was followed by a down-shift in temperature to 60°C to mimic cold seawater injection into a hot reservoir. Souring did not occur at 80°C, but commenced within hours at 60°C. Microcosms were monitored for sulfate reduction and organic acids in combination with next generation sequencing of 16S rRNA genes (Ion Torrent, Illumina MiSeq). Through a combination of high

  10. Genome-Assisted Analysis of Dissimilatory Metal-Reducing Bacteria

    SciTech Connect

    Fredrickson, Jim K.; Romine, Margaret F.

    2005-06-01

    Whole genome sequence for Shewanella oneidensis and Geobacter sulfurreducens has provided numerous new biological insights into the function of these model dissimilatory metal-reducing bacteria. Many of the discoveries, including the identification of a high number of c-type cytochromes in both organisms, have been the result of comparative genomic analyses including several that were experimentally confirmed. Genome sequence has also aided the identification of genes important for the reduction of metal ions and other electron acceptors utilized by these organisms during anaerobic growth by facilitating the identification of genes disrupted by random insertions. Technologies for assaying global expression patterns for genes (mRNA) and proteins have also been enabled by the availability of genome sequence but their application has been limited mainly to the analysis of the role of global regulatory genes and to identifying genes expressed or repressed in response to specific electron acceptors. It is anticipated that details regarding the mechanisms of metal ion respiration, and metabolism in general, will eventually be revealed by comprehensive, systems-level analyses enabled by functional genomic analyses.

  11. [Achievement of Sulfate-Reducing Anaerobic Ammonium Oxidation Reactor Started with Nitrate-Reducting Anaerobic Ammonium Oxidation].

    PubMed

    Liu, Zheng-chuan; Yuan, Lin-jiang; Zhou, Guo-biao; Li, Jing

    2015-09-01

    The transformation of nitrite-reducing anaerobic ammonium oxidation to sulfate-reducing anaerobic ammonium oxidation in an UASB was performed and the changes in microbial community were studied. The result showed that the sulfate reducing anaerobic ammonium oxidation process was successfully accomplished after 177 days' operation. The removal rate of ammonium nitrogen and sulfate were up to 58. 9% and 15. 7%, the removing load of ammonium nitrogen and sulfate were 74. 3 mg.(L.d)-1 and 77. 5 mg.(L.d)-1 while concentration of ammonium nitrogen and sulfate of influent were 130 mg.(L.d)-1 and 500 mg.(L.d)-1, respectively. The lost nitrogen and sulphur was around 2 in molar ratio. The pH value of the effluent was lower than that of the influent. Instead of Candidatus brocadia in nitrite reducing anaerobic ammonium oxidation granular sludge, Bacillus benzoevorans became the dominant species in sulfate reducing anaerobic ammonium oxidation sludge. The dominant bacterium in the two kinds of anaerobic ammonium oxidation process is different. Our results imply that the two anaerobic ammonium oxidation processes are carried out by different kind of bacterium. PMID:26717697

  12. Sulfide response analysis for sulfide control using a pS electrode in sulfate reducing bioreactors.

    PubMed

    Villa-Gomez, D K; Cassidy, J; Keesman, K J; Sampaio, R; Lens, P N L

    2014-03-01

    Step changes in the organic loading rate (OLR) through variations in the influent chemical oxygen demand (CODin) concentration or in the hydraulic retention time (HRT) at constant COD/SO4(2-) ratio (0.67) were applied to create sulfide responses for the design of a sulfide control in sulfate reducing bioreactors. The sulfide was measured using a sulfide ion selective electrode (pS) and the values obtained were used to calculate proportional-integral-derivative (PID) controller parameters. The experiments were performed in an inverse fluidized bed bioreactor with automated operation using the LabVIEW software version 2009(®). A rapid response and high sulfide increment was obtained through a stepwise increase in the CODin concentration, while a stepwise decrease to the HRT exhibited a slower response with smaller sulfide increment. Irrespective of the way the OLR was decreased, the pS response showed a time-varying behavior due to sulfide accumulation (HRT change) or utilization of substrate sources that were not accounted for (CODin change). The pS electrode response, however, showed to be informative for applications in sulfate reducing bioreactors. Nevertheless, the recorded pS values need to be corrected for pH variations and high sulfide concentrations (>200 mg/L). PMID:24361702

  13. Biologically-Induced Precipitation of Minerals in a Medium with Zinc Under Sulfate-Reducing Conditions.

    PubMed

    Wolicka, Dorota; Borkowski, Andrzej; Jankiewicz, Urszula; Stępień, Wojciech; Kowalczyk, Paweł

    2015-01-01

    Sulfate-reducing microbial communities were enriched from soils collected in areas with crude-oil exploitation. Cultures were grown in modified Postgate C medium and minimal medium, with ethanol or lactate as an electron donor. The batch cultures were grown with addition of zinc in concentrations of 100-700 mg/l. A lack of increased protein concentration in the solutions compared with the control batch, was noted in cultures containing over 200 mg Zn2+/l. The 16S rRNA method was applied to determine the specific composition of the selected microorganism communities. The analysis indicated the presence of Desulfovibrio spp., Desulfobulbus spp. and Desulfotomaculum spp. in the communities. Diffractometric analysis indicated the presence of biogenic sphalerite in cultures with 100 and 200 mg Zn2+/l and elemental sulfur in cultures with 200 mg Zn2+/l. Other post culture sediments (300-700 mg Zn2+/l) contained only hopeite [Zn3(PO4)2·4H2O] formed abiotically during the experiment, which was confirmed by studies of the activity of sulfate-reducing microbial communities. PMID:26373175

  14. Stable isotopic studies of n-alkane metabolism by a sulfate-reducing bacterial enrichment culture.

    PubMed

    Davidova, Irene A; Gieg, Lisa M; Nanny, Mark; Kropp, Kevin G; Suflita, Joseph M

    2005-12-01

    Gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy were used to study the metabolism of deuterated n-alkanes (C6 to C12) and 1-13C-labeled n-hexane by a highly enriched sulfate-reducing bacterial culture. All substrates were activated via fumarate addition to form the corresponding alkylsuccinic acid derivatives as transient metabolites. Formation of d14-hexylsuccinic acid in cell extracts from exogenously added, fully deuterated n-hexane confirmed that this reaction was the initial step in anaerobic alkane metabolism. Analysis of resting cell suspensions amended with 1-13C-labeled n-hexane confirmed that addition of the fumarate occurred at the C-2 carbon of the parent substrate. Subsequent metabolism of hexylsuccinic acid resulted in the formation of 4-methyloctanoic acid, and 3-hydroxy-4-methyloctanoic acid was tentatively identified. We also found that 13C nuclei from 1-13C-labeled n-hexane became incorporated into the succinyl portion of the initial metabolite in a manner that indicated that 13C-labeled fumarate was formed and recycled during alkane metabolism. Collectively, the findings obtained with a sulfate-reducing culture using isotopically labeled alkanes augment and support the previously proposed pathway (H. Wilkes, R. Rabus, T. Fischer, A. Armstroff, A. Behrends, and F. Widdel, Arch. Microbiol. 177:235-243, 2002) for metabolism of deuterated n-hexane by a denitrifying bacterium. PMID:16332800

  15. Formation of diphenylthioarsinic acid from diphenylarsinic acid under anaerobic sulfate-reducing soil conditions.

    PubMed

    Hisatomi, Shihoko; Guan, Ling; Nakajima, Mami; Fujii, Kunihiko; Nonaka, Masanori; Harada, Naoki

    2013-11-15

    Diphenylarsinic acid (DPAA) is a toxic phenylarsenical compound often found around sites contaminated with phenylarsenic chemical warfare agents, diphenylcyanoarsine or diphenylchloroarsine, which were buried in soil after the World Wars. This research concerns the elucidation of the chemical structure of an arsenic metabolite transformed from DPAA under anaerobic sulfate-reducing soil conditions. In LC/ICP-MS analysis, the retention time of the metabolite was identical to that of a major phenylarsenical compound synthesized by chemical reaction of DPAA and hydrogen sulfide. Moreover the mass spectra for the two compounds measured using LC/TOF-MS were similar. Subsequent high resolution mass spectral analysis indicated that two major ions at m/z 261 and 279, observed on both mass spectra, were attributable to C12H10AsS and C12H12AsSO, respectively. These findings strongly suggest that the latter ion is the molecular-related ion ([M+H](+)) of diphenylthioarsinic acid (DPTA; (C6H5)2AsS(OH)) and the former ion is its dehydrated fragment. Thus, our results reveal that DPAA can be transformed to DPTA, as a major metabolite, under sulfate-reducing soil conditions. Moreover, formation of diphenyldithioarsinic acid and subsequent dimerization were predicted by the chemical reaction analysis of DPAA with hydrogen sulfide. This is the first report to elucidate the occurrence of DPAA-thionation in an anaerobic soil. PMID:24007995

  16. Bacteria-assisted preparation of nano α-Fe2O3 red pigment powders from waste ferrous sulfate.

    PubMed

    Li, Xiang; Wang, Chuankai; Zeng, Yu; Li, Panyu; Xie, Tonghui; Zhang, Yongkui

    2016-11-01

    Massive ferrous sulfate with excess sulfuric acid is produced in titanium dioxide industry each year, ending up stockpiled or in landfills as solid waste, which is hazardous to environment and in urgent demand to be recycled. In this study, waste ferrous sulfate was used as a second raw material to synthesize nano α-Fe2O3 red pigment powders with a bacteria-assisted oxidation process by Acidithiobacillus ferrooxidans. The synthesis route, mainly consisting of bio-oxidation, precipitation and calcination, was investigated by means of titration, thermogravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscope (SEM) and X-ray fluorescence (XRF) to obtain optimum conditions. Under the optimum conditions, nano α-Fe2O3 red pigment powders contained 98.24wt.% of Fe2O3 were successfully prepared, with a morphology of spheroidal and particle size ranged from 22nm to 86nm and averaged at 45nm. Moreover, the resulting product fulfilled ISO 1248-2006, the standards of iron oxide pigments. PMID:27344257

  17. Ubiquity and Diversity of Dissimilatory (Per)chlorate-Reducing Bacteria

    PubMed Central

    Coates, John D.; Michaelidou, Urania; Bruce, Royce A.; O’Connor, Susan M.; Crespi, Jill N.; Achenbach, Laurie A.

    1999-01-01

    Environmental contamination with compounds containing oxyanions of chlorine, such as perchlorate or chlorate [(per)chlorate] or chlorine dioxide, has been a constantly growing problem over the last 100 years. Although the fact that microbes reduce these compounds has been recognized for more than 50 years, only six organisms which can obtain energy for growth by this metabolic process have been described. As part of a study to investigate the diversity and ubiquity of microorganisms involved in the microbial reduction of (per)chlorate, we enumerated the (per)chlorate-reducing bacteria (ClRB) in very diverse environments, including pristine and hydrocarbon-contaminated soils, aquatic sediments, paper mill waste sludges, and farm animal waste lagoons. In all of the environments tested, the acetate-oxidizing ClRB represented a significant population, whose size ranged from 2.31 × 103 to 2.4 × 106 cells per g of sample. In addition, we isolated 13 ClRB from these environments. All of these organisms could grow anaerobically by coupling complete oxidation of acetate to reduction of (per)chlorate. Chloride was the sole end product of this reductive metabolism. All of the isolates could also use oxygen as a sole electron acceptor, and most, but not all, could use nitrate. The alternative electron donors included simple volatile fatty acids, such as propionate, butyrate, or valerate, as well as simple organic acids, such as lactate or pyruvate. Oxidized-minus-reduced difference spectra of washed whole-cell suspensions of the isolates had absorbance maxima close to 425, 525, and 550 nm, which are characteristic of type c cytochromes. In addition, washed cell suspensions of all of the ClRB isolates could dismutate chlorite, an intermediate in the reductive metabolism of (per)chlorate, into chloride and molecular oxygen. Chlorite dismutation was a result of the activity of a single enzyme which in pure form had a specific activity of approximately 1,928 μmol of chlorite

  18. The first genomic and proteomic characterization of a deep-sea sulfate reducer: insights into the piezophilic lifestyle of Desulfovibrio piezophilus.

    PubMed

    Pradel, Nathalie; Ji, Boyang; Gimenez, Grégory; Talla, Emmanuel; Lenoble, Patricia; Garel, Marc; Tamburini, Christian; Fourquet, Patrick; Lebrun, Régine; Bertin, Philippe; Denis, Yann; Pophillat, Matthieu; Barbe, Valérie; Ollivier, Bernard; Dolla, Alain

    2013-01-01

    Desulfovibrio piezophilus strain C1TLV30(T) is a piezophilic anaerobe that was isolated from wood falls in the Mediterranean deep-sea. D. piezophilus represents a unique model for studying the adaptation of sulfate-reducing bacteria to hydrostatic pressure. Here, we report the 3.6 Mbp genome sequence of this piezophilic bacterium. An analysis of the genome revealed the presence of seven genomic islands as well as gene clusters that are most likely linked to life at a high hydrostatic pressure. Comparative genomics and differential proteomics identified the transport of solutes and amino acids as well as amino acid metabolism as major cellular processes for the adaptation of this bacterium to hydrostatic pressure. In addition, the proteome profiles showed that the abundance of key enzymes that are involved in sulfate reduction was dependent on hydrostatic pressure. A comparative analysis of orthologs from the non-piezophilic marine bacterium D. salexigens and D. piezophilus identified aspartic acid, glutamic acid, lysine, asparagine, serine and tyrosine as the amino acids preferentially replaced by arginine, histidine, alanine and threonine in the piezophilic strain. This work reveals the adaptation strategies developed by a sulfate reducer to a deep-sea lifestyle. PMID:23383081

  19. Microbial diversity in Los Azufres geothermal field (Michoacán, Mexico) and isolation of representative sulfate and sulfur reducers.

    PubMed

    Brito, Elcia M S; Villegas-Negrete, Norberto; Sotelo-González, Irene A; Caretta, César A; Goñi-Urriza, Marisol; Gassie, Claire; Hakil, Florence; Colin, Yannick; Duran, Robert; Gutiérrez-Corona, Felix; Piñón-Castillo, Hilda A; Cuevas-Rodríguez, Germán; Malm, Olaf; Torres, João P M; Fahy, Anne; Reyna-López, Georgina E; Guyoneaud, Rémy

    2014-03-01

    Los Azufres spa consists of a hydrothermal spring system in the Mexican Volcanic Axis. Five samples (two microbial mats, two mud pools and one cenote water), characterized by high acidity (pH between 1 and 3) and temperatures varying from 27 to 87 °C, were investigated for their microbial diversity by Terminal-Restriction Fragment Length Polymorphism (T-RFLP) and 16S rRNA gene library analyses. These data are the first to describe microbial diversity from Los Azufres geothermal belt. The data obtained from both approaches suggested a low bacterial diversity in all five samples. Despite their proximity, the sampling points differed by their physico-chemical conditions (mainly temperature and matrix type) and thus exhibited different dominant bacterial populations: anoxygenic phototrophs related to the genus Rhodobacter in the biomats, colorless sulfur oxidizers Acidithiobacillus sp. in the warm mud and water samples, and Lyzobacter sp.-related populations in the hot mud sample (87 °C). Molecular data also allowed the detection of sulfate and sulfur reducers related to Thermodesulfobium and Desulfurella genera. Several strains affiliated to both genera were enriched or isolated from the mesophilic mud sample. A feature common to all samples was the dominance of bacteria involved in sulfur and iron biogeochemical cycles (Rhodobacter, Acidithiobacillus, Thiomonas, Desulfurella and Thermodesulfobium genera). PMID:24446065

  20. Microbial Corrosion in Linepipe Steel Under the Influence of a Sulfate-Reducing Consortium Isolated from an Oil Field

    NASA Astrophysics Data System (ADS)

    AlAbbas, Faisal M.; Williamson, Charles; Bhola, Shaily M.; Spear, John R.; Olson, David L.; Mishra, Brajendra; Kakpovbia, Anthony E.

    2013-11-01

    This work investigates microbiologically influenced corrosion of API 5L X52 linepipe steel by a sulfate-reducing bacteria (SRB) consortium. The SRB consortium used in this study was cultivated from a sour oil well in Louisiana, USA. 16S rRNA gene sequence analysis indicated that the mixed bacterial consortium contained three phylotypes: members of Proteobacteria ( Desulfomicrobium sp.), Firmicutes ( Clostridium sp.), and Bacteroidetes ( Anaerophaga sp.). The biofilm and the pits that developed with time were characterized using field emission scanning electron microscopy (FE-SEM). In addition, electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) and open circuit potential (OCP) were used to analyze the corrosion behavior. Through circuit modeling, EIS results were used to interpret the physicoelectric interactions between the electrode, biofilm and solution interfaces. The results confirmed that extensive localized corrosion activity of SRB is due to a formed biofilm in conjunction with a porous iron sulfide layer on the metal surface. X-ray diffraction (XRD) revealed semiconductive corrosion products predominantly composed of a mixture of siderite (FeCO3), iron sulfide (Fe x S y ), and iron (III) oxide-hydroxide (FeOOH) constituents in the corrosion products for the system exposed to the SRB consortium.

  1. Biodegradation of munitions compounds by a sulfate reducing bacterial enrichment culture

    SciTech Connect

    Boopathy, R.; Manning, J.

    1997-08-01

    The degradation of several munitions compounds was studied. The compounds included 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine, octahydro-1,3,5,7-tetranitro-1,3,5,7-tetraazocine, 2,4,6-trinitrobenzene (TNB), and 2,4-dinitrotoluene. All of the compounds studied were degraded by the sulfate reducing bacterial (SRB) enrichment culture. The SRB culture did not use the munitions compounds as their sole source of carbon. However, all the munitions compounds tested served as the sole source of nitrogen for the SRB culture. Degradation of munitions compounds was achieved by a co-metabolic process. The SRB culture used a variety of carbon sources including pyruvate, ethanol, formate, lactate, and H{sub 2}-CO{sub 2}. The SRB culture was an incomplete oxidizer, unable to carry out the terminal oxidation of organic substrates to CO{sub 2} as the sole product, and it did not use acetate or methanol as a carbon source. In addition to serving as nitrogen sources, the munitions compounds also served as electron acceptors in the absence of sulfate. A soil slurry experiment with 5% and 10% munitions compounds-contaminated soil showed that the contaminant TNT was metabolized by the SRB culture in the presence of pyruvate as electron donor. This culture may be useful in decontaminating munitions compounds-contaminated soil and water under anaerobic conditions.

  2. Transformation of 3- and 4-Picoline under Sulfate-Reducing Conditions

    PubMed Central

    Kaiser, J.-P.; Minard, R. D.; Bollag, J.-M.

    1993-01-01

    A microbial population which transformed 3- and 4-picoline under sulfate-reducing conditions was isolated from a subsurface soil which had been previously exposed to different N-substituted aromatic compounds for several years. In the presence of sulfate, the microbial culture transformed 3- and 4-picoline (0.4 mM) within 30 days. From the amounts of ammonia released and of sulfide that were determined during the transformation of 3-picoline, it can be concluded that the parent compound was mineralized to carbon dioxide and ammonia. During the transformation of 4-picoline, a UV-absorbing intermediate accumulated in the culture medium. This metabolite was identified as 2-hydroxy-4-picoline by gas chromatography-mass spectrometry and nuclear magnetic resonance analysis, and its further transformation was detected only after an additional month of incubation. The small amount of sulfide produced during the oxidation of 4-picoline and the generation of the hydroxylated metabolite indicated that the initial step in the metabolic pathway of 4-picoline was a monohydroxylation at position 2 of the heterocyclic aromatic ring. The 3- and 4-picoline-degrading cultures could also transform benzoic acid; however, the other methylated pyridine derivatives, 2-picoline, dimethyl-pyridines, and trimethylpyridines, were not degraded. PMID:16348885

  3. Anaerobic biodegradation of long-chain n-alkanes under sulfate-reducing conditions

    SciTech Connect

    Caldwell, M.E.; Suflita, J.M.; Garrett, R.M.; Prince, R.C.

    1998-07-15

    The ability of anaerobic microorganisms to degrade a wide variety of crude oil components was investigated using chronically hydrocarbon-contaminated marine sediments as the source of inoculum. When sulfate reduction was the predominant electron-accepting process, gas chromatographic analysis revealed almost complete n-alkane removal (C{sub 15}-C{sub 34}) from a weathered oil within 201 d of incubation. No alteration of the oil was detected in sterile control incubations or when nitrate served as an alternate electron acceptor. The amount of sulfate reduced in the oil-amended nonsterile incubations was more than enough to account for the complete mineralization of the n-alkane fraction of the oil; no loss of this anion was observed in sterile control incubations. The mineralization of the alkanes was confirmed using {sup 14}C-14,15-octacosane (C{sub 28}H{sub 58}), with 97% of the radioactivity recovered as {sup 14}CO{sub 2}. These findings extend the range of hydrocarbons known to be amenable to anaerobic biodegradation. Moreover, the rapid and extensive alteration in the n-alkanes can no longer be considered a defining characteristic of aerobic oil biodegradation processes alone.

  4. Sulfate Fining Chemistry in Oxidized and Reduced Soda-Lime-Silica Glasses

    SciTech Connect

    Matyas, Josef; Hrma, Pavel R.

    2005-05-13

    Various reducing agents were used and their additions were varied to (1) increase glass quality through eliminating defects from silica scum, (2) decrease SOx emissions through changing the kind and quantity of reducing agents, and (3) improve production efficiency through increased flexibility of glass redox control during continuous processing. The work included measuring silica sand dissolution and sulfate decomposition in melts from glass batches. Glass batches were heated at a temperature-increase rate deemed similar to that experienced in the melting furnace. The sulfate decomposition kinetics was investigated with thermogravimetric analysis-differential thermal analysis and evolved gas analysis. Sulfur concentrations in glasses quenched at different temperatures were determined using X-ray fluorescence spectroscopy. The distribution of residual sand (that which was not dissolved during the initial batch reactions) in the glass was obtained as a function of temperature with optical microscopy in thin-sections of melts. The fraction of undissolved sand was measured with X-ray diffraction. The results of the present study helped Visteon Inc. reduce the energy consumption and establish the batch containing 0.118 mass% of graphite as the best candidate for Visteon glass production. The improved glass batch has a lower potential for silica scum formation and for brown fault occurrence in the final glass product. It was established that bubbles trapped in the melt even at 1450 C have a high probability to be refined when reaching the hot zone in the glass furnace. Furthermore, silica sand does not accumulate at the glass surface and dissolves faster in the batch with graphite than in the batch with carbocite.

  5. Dynamics of methane production, sulfate reduction, and denitrification in a permanently waterlogged alder swamp

    SciTech Connect

    Westermann, P.; Ahring, B.K.

    1987-10-01

    The dynamics of sulfate reduction, methane production, and denitrification were investigated in a permanently waterlogged alder swamp. Molybdate, an inhibitor of sulfate reduction, stimulated methane production in soil slurries, thus suggesting competition for common substrates between sulfate-reducing and methane-producing bacteria. Acetate, hydrogen, and methanol were found to stimulate both sulfate reduction and methane production, while trimethylamine mainly stimulated methane production. Nitrate addition reduced both methane production and sulfate reduction, either as a consequence of competition of poisoning of the bacteria. Sulfate-reducing bacteria were only slightly limited by the availability of electron acceptors, while denitrifying bacteria were seriously limited by low nitrate concentrations. Arrhenius plots of the three processes revealed different responses to temperature changes in the slurries. Methane production was most sensitive to temperature changes, followed by denitrification and sulfate reduction. No significant differences between slope patterns were observed when comparing summer and winter measurements, indicating similar populations regarding temperature responses.

  6. Dynamics of Methane Production, Sulfate Reduction, and Denitrification in a Permanently Waterlogged Alder Swamp

    PubMed Central

    Westermann, Peter; Ahring, Birgitte Kiær

    1987-01-01

    The dynamics of sulfate reduction, methane production, and denitrification were investigated in a permanently waterlogged alder swamp. Molybdate, an inhibitor of sulfate reduction, stimulated methane production in soil slurries, thus suggesting competition for common substrates between sulfate-reducing and methane-producing bacteria. Acetate, hydrogen, and methanol were found to stimulate both sulfate reduction and methane production, while trimethylamine mainly stimulated methane production. Nitrate addition reduced both methane production and sulfate reduction, either as a consequence of competition or poisoning of the bacteria. Sulfate-reducing bacteria were only slightly limited by the availability of electron acceptors, while denitrifying bacteria were seriously limited by low nitrate concentrations. Arrhenius plots of the three processes revealed different responses to temperature changes in the slurries. Methane production was most sensitive to temperature changes, followed by denitrification and sulfate reduction. No significant differences between slope patterns were observed when comparing summer and winter measurements, indicating similar populations regarding temperature responses. PMID:16347472

  7. Tetrachloroethene transformation to trichloroethene and cis-1,2-dichloroethene by sulfate-reducing enrichment cultures

    SciTech Connect

    Bagley, D.M.; Gossett, J.M. )

    1990-08-01

    Tetrachloroethene, also known as perchloroethylene, was reductively dechlorinated to trichloroethene and cis-1,2-dichloroethene by laboratory sulfate-reducing enrichment cultures. The causative organism or group was not identified. However, tetrachloroethene was dechlorinated to trichloroethene in 50 mM bromoethane-sulfonate-inhibited enrichments and to trichloroethene and cis-1,2-dichloroethene in 3 mM fluoroacetate-inhibited enrichments. Overall transformation varied from 92% tetrachloroethene removal in 13 days to 22% removal in 65 days, depending on conditions of the inoculum, inhibitor used, and auxilliary substrate used. Neither lactate, acetate, methanol, isobutyric acid, valeric acid, isovaleric acid, hexanoic acid, succinic acid, nor hydrogen appeared directly to support tetrachloroethene dechlorination, although lactate-fed inocula demonstrated longer-term dechlorinating capability.

  8. High urinary sulfate concentration is associated with reduced risk of renal disease progression in type 2 diabetes.

    PubMed

    van den Born, Joost C; Frenay, Anne-Roos S; Bakker, Stephan J L; Pasch, Andreas; Hillebrands, Jan-Luuk; Lambers Heerspink, Hiddo J; van Goor, Harry

    2016-05-01

    Diabetes is associated with a high incidence of microvascular disease, including nephropathy. Diabetic nephropathy is the most common cause of chronic kidney disease in the Western world. Sulfate in the urine is the metabolic end product of hydrogen sulfide (H2S), a recent discovered gaseous signaling molecule. Urinary sulfate has earlier shown beneficial predictive properties in renal transplant recipients. Based on the protective role of exogenous H2S in experimental models of diabetic nephropathy, we aimed to cross-sectionally investigate the association of sulfate with renal risk markers, and to prospectively investigate its predictive value for renal events in patients with diabetic nephropathy. Post-hoc analysis on data of the sulodexide macroalbuminuria (Sun-MACRO) trial and the Prevention of Renal and Vascular End-Stage Disease (PREVEND) study was performed. A total of 1004 patients with type 2 diabetes were included. Urinary sulfate concentration was measured and cross-sectionally associated to renal risk markers by linear regression. Multivariable Cox regression analysis was performed to assess the prospective association of sulfate with renal events, which was defined as end stage renal disease or a doubling of baseline serum creatinine. Mean age was 63 ± 9 years, median sulfate concentration was 8.0 (IQR 5.8-11.4) mmol/L. Urinary sulfate positively associated with male gender, hemoglobin, and negatively associated with albuminuria at baseline. During follow-up for 12 (IQR 6-18) months, 38 renal events occurred. Each doubling of urinary sulfate was associated with a 19% (95%CI 1%-34%) lower risk of renal events, independent of adjustment for potential confounders, including age, estimated glomerular filtration rate (eGFR), and albuminuria. To conclude, higher urinary sulfate concentration is associated with a more beneficial profile of renal risk markers, and is independently associated with a reduced risk for renal events in type 2 diabetes patients

  9. Sulfate reducing bacterial community and in situ activity in mature fine tailings analyzed by real time qPCR and microsensor.

    PubMed

    Liu, Hong; Tan, Shuying; Yu, Tong; Liu, Yang

    2016-06-01

    Sulfate reducing bacteria (SRB) play significant roles in anaerobic environments in oil sands mature fine tailings (MFTs). Hydrogen sulfide (H2S) is produced during the biological sulfate reduction process. The production of toxic H2S is one of the concerns because it may hinder the landscape remediation efficiency of oil sands tailing ponds. In present study, the in situ activity and the community structure of SRB in MFT and gypsum amended MFT in two settling columns were investigated. Combined techniques of H2S microsensor and dissimilatory sulfite reductase β-subunit (dsrB) genes-based real time quantitative polymerase chain reaction (qPCR) were applied to detect the in situ H2S and the abundance of SRB. A higher diversity of SRB and more H2S were observed in gypsum amended MFT than that in MFT, indicating a higher sulfate reduction activity in gypsum amended MFT; in addition, the activity of SRB varied as depth in both MFT and gypsum amended MFT: the deeper the more H2S produced. Long-term plans for tailings management can be assessed more wisely with the information provided in this study. PMID:27266310

  10. Effects of intestinal bacteria-derived p-cresyl sulfate on Th1-type immune response in vivo and in vitro

    SciTech Connect

    Shiba, Takahiro Kawakami, Koji; Sasaki, Takashi; Makino, Ikuyo; Kato, Ikuo; Kobayashi, Toshihide; Uchida, Kazumi; Kaneko, Kimiyuki

    2014-01-15

    Protein fermentation by intestinal bacteria generates various compounds that are not synthesized by their hosts. An example is p-cresol, which is produced from tyrosine. Patients with chronic kidney disease (CKD) accumulate high concentrations of intestinal bacteria-derived p-cresyl sulfate (pCS), which is the major metabolite of p-cresol, in their blood, and this accumulation contributes to certain CKD-associated disorders. Immune dysfunction is a CKD-associated disorder that frequently contributes to infectious diseases among CKD patients. Although some studies imply pCS as an etiological factor, the relation between pCS and immune systems is poorly understood. In the present study, we investigated the immunological effects of pCS derived from intestinal bacteria in mice. For this purpose, we fed mice a tyrosine-rich diet that causes the accumulation of pCS in their blood. The mice were shown to exhibit decreased Th1-driven 2, 4-dinitrofluorobenzene-induced contact hypersensitivity response. The concentration of pCS in blood was negatively correlated with the degree of the contact hypersensitivity response. In contrast, the T cell-dependent antibody response was not influenced by the accumulated pCS. We also examined the in vitro cytokine responses by T cells in the presence of pCS. The production of IFN-γ was suppressed by pCS. Further, pCS decreased the percentage of IFN-γ-producing Th1 cells. Our results suggest that intestinal bacteria-derived pCS suppressesTh1-type cellular immune responses. - Highlights: • Mice fed a tyrosine-rich diet accumulated p-cresyl sulfate in their blood. • p-Cresyl sulfate negatively correlated with contact hypersensitivity response. • The in vitro production of IFN-γ was suppressed by p-cresyl sulfate. • p-Cresyl sulfate decreased the percentage of IFN-γ-producing Th1 cells in vitro.

  11. Desulfonatronum Thiodismutans sp. nov., a Novel Alkaliphilic, Sulfate-reducing Bacterium Capable of Lithoautotrophic Growth

    NASA Technical Reports Server (NTRS)

    Pikuta, Elena V.; Hoover, Richard B.; Bej, Asim K.; Marsic, Damien; Whitman, William B.; Cleland, David; Krader, Paul

    2003-01-01

    A novel alkaliphilic, sulfate-reducing bacterium, strain MLF1(sup T), was isolated from sediments of soda Mono Lake, California. Gram-negative vibrio-shaped cells were observed, which were 0.6-0.7 x 1.2-2.7 microns in size, motile by a single polar flagellum and occurred singly, in pairs or as short spirilla. Growth was observed at 15-48 C (optimum, 37 C), > 1-7 % NaCI, w/v (optimum, 3%) and pH 8.0-10.0 (optimum, 9.5). The novel isolate is strictly alkaliphilic, requires a high concentration of carbonate in the growth medium and is obligately anaerobic and catalase-negative. As electron donors, strain MLF1(sup T) uses hydrogen, formate and ethanol. Sulfate, sulfite and thiosulfate (but not sulfur or nitrate) can be used as electron acceptors. The novel isolate is a lithoheterotroph and a facultative lithoautotroph that is able to grow on hydrogen without an organic source of carbon. Strain MLF1(sup T) is resistant to kanamycin and gentamicin, but sensitive to chloramphenicol and tetracycline. The DNA G+C content is 63.0 mol% (HPLC). DNA-DNA hybridization with the most closely related species, Desulfonatronum lacustre Z-7951(sup T), exhibited 51 % homology. Also, the genome size (1.6 x 10(exp 9) Da) and T(sub m) value of the genomic DNA (71 +/- 2 C) for strain MLF1(sup T) were significantly different from the genome size (2.1 x 10(exp 9) Da) and T(sub m) value (63 +/- 2 C) for Desulfonatronum lacustre Z-7951(sup T). On the basis of physiological and molecular properties, the isolate was considered to be a novel species of the genus Desulfonatronum, for which the name Desulfonatronum thiodismutans sp. nov. is proposed (the type strain is MLF1(sup T) = ATCC BAA-395(sup T) = DSM 14708(sup T)).

  12. Continuous enrichment culturing of thermophiles under sulfate and nitrate-reducing conditions and at deep-sea hydrostatic pressures.

    PubMed

    Houghton, J L; Seyfried, W E; Banta, A B; Reysenbach, A-L

    2007-03-01

    A continuous culture bioreactor was developed to enrich for nitrate and sulfate reducing thermophiles under in situ deep-sea pressures. The ultimate objective of this experimental design was to be able to study microbial activities at chemical and physical conditions relevant to seafloor hydrothermal vents. Sulfide, sulfate and oxide minerals from sampled seafloor vent-chimney structures [East Pacific Rise (9 degrees 46'N)] served as source mineral and microbial inoculum for enrichment culturing using nitrate and sulfate-enriched media at 70 and 90 degrees C and 250 bars. Changes in microbial diversity during the continuous reaction flow were monitored using denaturing gradient gel electrophoresis (DGGE) of PCR amplified 16S rRNA gene fragments. Time series changes in fluid chemistry were also monitored throughout the experiment to assess the feedback between mineral-fluid reaction and metabolic processes. Data indicate a shift from the dominance of epsilon Proteobacteria in the initial inoculum to the several Aquificales-like phylotypes in nitrate-reducing enrichment media and Thermodesulfobacteriales in the sulfate-reducing enrichment media. Methanogens were detected in the original sulfide sample and grew in selected sulfate-enriched experiments. Microbial interactions with anhydrite and pyrrhotite in the chimney material resulted in measurable changes in fluid chemistry despite a fluid residence time only 75 min in the reactor. Changes in temperature rather than source material resulted in greater differences in microbial enrichments and mediated geochemical reactions. PMID:17221162

  13. Inhibition of a U(VI)- and sulfate-reducing consortia by U(VI).

    PubMed

    Nyman, Jennifer L; Wu, Hsin-I; Gentile, Margaret E; Kitanidis, Peter K; Criddle, Craig S

    2007-09-15

    The stimulation of microbial U(VI) reduction is currently being investigated as a means to reduce uranium's mobility in groundwater, but little is known about the concentration at which U(VI) might inhibit microbial activity, or the effect of U(VI) on bacterial community structure. We investigated these questions with an ethanol-fed U(VI)- and sulfate-reducing enrichment developed from sediment from the site of an ongoing field biostimulation experiment at Area 3 of the Oak Ridge Field Research Center (FRC). Sets of triplicate enrichments were spiked with increasing concentrations of U(VI) (from 49 microm to 9.2 mM). As the U(VI) concentration increased to 224 microM, the culture's production of acetate from ethanol slowed, and at or above 1.6 mM U(VI) little acetate was produced over the time frame of the experiment. An uncoupling inhibition model was applied to the data, and the inhibition coefficient for U(VI), Ku, was found to be approximately 100 microM U(VI), or 24 mg/L, indicating the inhibitory effect is relevant at highly contaminated sites. Microbial community structure at the conclusion of the experiment was analyzed with terminal restriction fragment length polymorphism (T-RFLP) analysis. T-RFs associated with Desulfovibrio-like organisms decreased in relative abundance with increasing U(VI) concentration, whereas Clostridia-like T-RFs increased. PMID:17948804

  14. Successional Development of Sulfate-Reducing Bacterial Populations and Their Activities in a Wastewater Biofilm Growing under Microaerophilic Conditions

    PubMed Central

    Ito, Tsukasa; Okabe, Satoshi; Satoh, Hisashi; Watanabe, Yoshimasa

    2002-01-01

    A combination of fluorescence in situ hybridization, microprofiles, denaturing gradient gel electrophoresis of PCR-amplified 16S ribosomal DNA fragments, and 16S rRNA gene cloning analysis was applied to investigate successional development of sulfate-reducing bacteria (SRB) community structure and in situ sulfide production activity within a biofilm growing under microaerophilic conditions (dissolved oxygen concentration in the bulk liquid was in the range of 0 to 100 μM) and in the presence of nitrate. Microelectrode measurements showed that oxygen penetrated 200 μm from the surface during all stages of biofilm development. The first sulfide production of 0.32 μmol of H2S m−2 s−1 was detected below ca. 500 μm in the 3rd week and then gradually increased to 0.70 μmol H2S m−2 s−1 in the 8th week. The most active sulfide production zone moved upward to the oxic-anoxic interface and intensified with time. This result coincided with an increase in SRB populations in the surface layer of the biofilm. The numbers of the probe SRB385- and 660-hybridized SRB populations significantly increased to 7.9 × 109 cells cm−3 and 3.6 × 109 cells cm−3, respectively, in the surface 400 μm during an 8-week cultivation, while those populations were relatively unchanged in the deeper part of the biofilm, probably due to substrate transport limitation. Based on 16S rRNA gene cloning analysis data, clone sequences that related to Desulfomicrobium hypogeium (99% sequence similarity) and Desulfobulbus elongatus (95% sequence similarity) were most frequently found. Different molecular analyses confirmed that Desulfobulbus, Desulfovibrio, and Desulfomicrobium were found to be the numerically important members of SRB in this wastewater biofilm. PMID:11872492

  15. Prokaryotic Community Structure and Sulfate Reducer Activity in Water from High-Temperature Oil Reservoirs with and without Nitrate Treatment▿ †

    PubMed Central

    Gittel, Antje; Sørensen, Ketil Bernt; Skovhus, Torben Lund; Ingvorsen, Kjeld; Schramm, Andreas

    2009-01-01

    Sulfate-reducing prokaryotes (SRP) cause severe problems like microbial corrosion and reservoir souring in seawater-injected oil production systems. One strategy to control SRP activity is the addition of nitrate to the injection water. Production waters from two adjacent, hot (80°C) oil reservoirs, one with and one without nitrate treatment, were compared for prokaryotic community structure and activity of SRP. Bacterial and archaeal 16S rRNA gene analyses revealed higher prokaryotic abundance but lower diversity for the nitrate-treated field. The 16S rRNA gene clone libraries from both fields were dominated by sequences affiliated with Firmicutes (Bacteria) and Thermococcales (Archaea). Potential heterotrophic nitrate reducers (Deferribacterales) were exclusively found at the nitrate-treated field, possibly stimulated by nitrate addition. Quantitative PCR of dsrAB genes revealed that archaeal SRP (Archaeoglobus) dominated the SRP communities, but with lower relative abundance at the nitrate-treated site. Bacterial SRP were found in only low abundance at both sites and were nearly exclusively affiliated with thermophilic genera (Desulfacinum and Desulfotomaculum). Despite the high abundance of archaeal SRP, no archaeal SRP activity was detected in [35S]sulfate incubations at 80°C. Sulfate reduction was found at 60°C in samples from the untreated field and accompanied by the growth of thermophilic bacterial SRP in batch cultures. Samples from the nitrate-treated field generally lacked SRP activity. These results indicate that (i) Archaeoglobus can be a major player in hot oil reservoirs, and (ii) nitrate may act in souring control—not only by inhibiting SRP, but also by changing the overall community structure, including the stimulation of competitive nitrate reducers. PMID:19801479

  16. EFFECT OF BACTERIAL SULFATE REDUCTION ON IRON-CORROSION SCALES

    EPA Science Inventory

    Iron-sulfur geochemistry is important in many natural and engineered environments including drinking water systems. In the anaerobic environment beneath scales of corroding iron drinking water distribution system pipes, sulfate reducing bacteria (SRB) produce sulfide from natura...

  17. Metabolic associations with archaea drive shifts in hydrogen isotope fractionation in sulfate-reducing bacterial lipids in cocultures and methane seeps.

    PubMed

    Dawson, K S; Osburn, M R; Sessions, A L; Orphan, V J

    2015-09-01

    Correlation between hydrogen isotope fractionation in fatty acids and carbon metabolism in pure cultures of bacteria indicates the potential of biomarker D/H analysis as a tool for diagnosing carbon substrate usage in environmental samples. However, most environments, in particular anaerobic habitats, are built from metabolic networks of micro-organisms rather than a single organism. The effect of these networks on D/H of lipids has not been explored and may complicate the interpretation of these analyses. Syntrophy represents an extreme example of metabolic interdependence. Here, we analyzed the effect of metabolic interactions on the D/H biosignatures of sulfate-reducing bacteria (SRB) using both laboratory maintained cocultures of the methanogen Methanosarcina acetivorans and the SRB Desulfococcus multivorans in addition to environmental samples harboring uncultured syntrophic consortia of anaerobic methane-oxidizing archaea (ANME) and sulfate-reducing Deltaproteobacteria (SRB) recovered from deep-sea methane seeps. Consistent with previously reported trends, we observed a ~80‰ range in hydrogen isotope fractionation (ε(lipid-water)) for D. multivorans grown under different carbon assimilation conditions, with more D-enriched values associated with heterotrophic growth. In contrast, for cocultures of D. multivorans with M. acetivorans, we observed a reduced range of ε(lipid-water) values (~36‰) across substrates with shifts of up to 61‰ compared to monocultures. Sediment cores from methane seep settings in Hydrate Ridge (offshore Oregon, USA) showed similar D-enrichment in diagnostic SRB fatty acids coinciding with peaks in ANME/SRB consortia concentration suggesting that metabolic associations are connected to the observed shifts in ε(lipid-water) values. PMID:25923659

  18. Draft Genome Sequence of Desulfitobacterium hafniense Strain DH, a Sulfate-Reducing Bacterium Isolated from Paddy Soils

    PubMed Central

    Zhang, Xi; Li, Guo-Xiang; Chen, Song-Can; Jia, Xiao-Yu; Wu, Kun; Cao, Chang-Li

    2016-01-01

    Desulfitobacterium hafniense strain DH is a sulfate-reducing species. Here, we report the draft genome sequence of strain DH, with a size of 5,368,588 bp, average G+C content of 47.48%, and 5,296 predicted protein-coding sequences. PMID:26868389

  19. Comparison of Mechanisms of Alkane Metabolism under Sulfate-Reducing Conditions among Two Bacterial Isolates and a Bacterial Consortium

    PubMed Central

    Callaghan, Amy V.; Gieg, Lisa M.; Kropp, Kevin G.; Suflita, Joseph M.; Young, Lily Y.

    2006-01-01

    Recent studies have demonstrated that fumarate addition and carboxylation are two possible mechanisms of anaerobic alkane degradation. In the present study, we surveyed metabolites formed during growth on hexadecane by the sulfate-reducing isolates AK-01 and Hxd3 and by a mixed sulfate-reducing consortium. The cultures were incubated with either protonated or fully deuterated hexadecane; the sulfate-reducing consortium was also incubated with [1,2-13C2]hexadecane. All cultures were extracted, silylated, and analyzed by gas chromatography-mass spectrometry. We detected a suite of metabolites that support a fumarate addition mechanism for hexadecane degradation by AK-01, including methylpentadecylsuccinic acid, 4-methyloctadecanoic acid, 4-methyloctadec-2,3-enoic acid, 2-methylhexadecanoic acid, and tetradecanoic acid. By using d34-hexadecane, mass spectral evidence strongly supporting a carbon skeleton rearrangement of the first intermediate, methylpentadecylsuccinic acid, was demonstrated for AK-01. Evidence indicating hexadecane carboxylation was not found in AK-01 extracts but was observed in Hxd3 extracts. In the mixed sulfate-reducing culture, however, metabolites consistent with both fumarate addition and carboxylation mechanisms of hexadecane degradation were detected, which demonstrates that multiple alkane degradation pathways can occur simultaneously within distinct anaerobic communities. Collectively, these findings underscore that fumarate addition and carboxylation are important alkane degradation mechanisms that may be widespread among phylogenetically and/or physiologically distinct microorganisms. PMID:16751542

  20. Transcription Factors Exhibit Differential Conservation in Bacteria with Reduced Genomes.

    PubMed

    Galán-Vásquez, Edgardo; Sánchez-Osorio, Ismael; Martínez-Antonio, Agustino

    2016-01-01

    The description of transcriptional regulatory networks has been pivotal in the understanding of operating principles under which organisms respond and adapt to varying conditions. While the study of the topology and dynamics of these networks has been the subject of considerable work, the investigation of the evolution of their topology, as a result of the adaptation of organisms to different environmental conditions, has received little attention. In this work, we study the evolution of transcriptional regulatory networks in bacteria from a genome reduction perspective, which manifests itself as the loss of genes at different degrees. We used the transcriptional regulatory network of Escherichia coli as a reference to compare 113 smaller, phylogenetically-related γ-proteobacteria, including 19 genomes of symbionts. We found that the type of regulatory action exerted by transcription factors, as genomes get progressively smaller, correlates well with their degree of conservation, with dual regulators being more conserved than repressors and activators in conditions of extreme reduction. In addition, we found that the preponderant conservation of dual regulators might be due to their role as both global regulators and nucleoid-associated proteins. We summarize our results in a conceptual model of how each TF type is gradually lost as genomes become smaller and give a rationale for the order in which this phenomenon occurs. PMID:26766575

  1. Transcription Factors Exhibit Differential Conservation in Bacteria with Reduced Genomes

    PubMed Central

    Galán-Vásquez, Edgardo; Sánchez-Osorio, Ismael; Martínez-Antonio, Agustino

    2016-01-01

    The description of transcriptional regulatory networks has been pivotal in the understanding of operating principles under which organisms respond and adapt to varying conditions. While the study of the topology and dynamics of these networks has been the subject of considerable work, the investigation of the evolution of their topology, as a result of the adaptation of organisms to different environmental conditions, has received little attention. In this work, we study the evolution of transcriptional regulatory networks in bacteria from a genome reduction perspective, which manifests itself as the loss of genes at different degrees. We used the transcriptional regulatory network of Escherichia coli as a reference to compare 113 smaller, phylogenetically-related γ-proteobacteria, including 19 genomes of symbionts. We found that the type of regulatory action exerted by transcription factors, as genomes get progressively smaller, correlates well with their degree of conservation, with dual regulators being more conserved than repressors and activators in conditions of extreme reduction. In addition, we found that the preponderant conservation of dual regulators might be due to their role as both global regulators and nucleoid-associated proteins. We summarize our results in a conceptual model of how each TF type is gradually lost as genomes become smaller and give a rationale for the order in which this phenomenon occurs. PMID:26766575

  2. Dendritic Polyglycerol Sulfate Inhibits Microglial Activation and Reduces Hippocampal CA1 Dendritic Spine Morphology Deficits.

    PubMed

    Maysinger, Dusica; Gröger, Dominic; Lake, Andrew; Licha, Kai; Weinhart, Marie; Chang, Philip K-Y; Mulvey, Rose; Haag, Rainer; McKinney, R Anne

    2015-09-14

    Hyperactivity of microglia and loss of functional circuitry is a common feature of many neurological disorders including those induced or exacerbated by inflammation. Herein, we investigate the response of microglia and changes in hippocampal dendritic postsynaptic spines by dendritic polyglycerol sulfate (dPGS) treatment. Mouse microglia and organotypic hippocampal slices were exposed to dPGS and an inflammogen (lipopolysaccharides). Measurements of intracellular fluorescence and confocal microscopic analyses revealed that dPGS is avidly internalized by microglia but not CA1 pyramidal neurons. Concentration and time-dependent response studies consistently showed no obvious toxicity of dPGS. The adverse effects induced by proinflammogen LPS exposure were reduced and dendritic spine morphology was normalized with the addition of dPGS. This was accompanied by a significant reduction in nitrite and proinflammatory cytokines (TNF-α and IL-6) from hyperactive microglia suggesting normalized circuitry function with dPGS treatment. Collectively, these results suggest that dPGS acts anti-inflammatory, inhibits inflammation-induced degenerative changes in microglia phenotype and rescues dendritic spine morphology. PMID:26218295

  3. Paracetamol, Ondansetron, Granisetron, Magnesium Sulfate and Lidocaine and Reduced Propofol Injection Pain

    PubMed Central

    Alipour, Mohammad; Tabari, Masoomeh; Alipour, Masoomeh

    2014-01-01

    Background: Propofol is a most widely used intravenous anesthetic drug. One of its most common complications is the pain upon injection; therefore, different methods, with various effects, have been proposed in order to alleviate the pain. Objectives: This study investigates the effects of paracetamol, ondansetron, granisetron, magnesium sulfate and lidocaine drugs on reducing the pain of propofol injection during anesthetic induction. Also, the hemodynamic changes will be analyzed. Patients and Methods: This is an interventional study containing 336 patients underwent elective orthopedic surgeries in Educational Hospitals of Mashhad University, using systematic sampling, the patients were divided into six groups. A 20-gauge needle was inserted into a venous vessel in the back of the hand and 100 cc of Ringer serum was injected into the vein, which was applied proximal to the injection site. Afterwards, paracetamol 2 mg/kg (group p), magnesium sulfate 2 mmol (group M), ondansetron 4 mg (group O), granisetron 2 mg (group G), lidocaine 40 mg (group L) and 5 cc saline (group S) were injected into the vessel, after 60 seconds, the tourniquet was opened. One quarter of the total dose of propofol (2.5 mg/kg) was injected with a flow rate of 4 mg/sec and then the injection pain was measured. Finally, the fentanyl (2 µg/kg), atracurium 0.5 mg/kg, and the remaining dose of propofol were injected and the vital signs were recorded before the administration of propofol and 1, 3, 5 and 10 minutes after the propofol injection. Results: The six groups did not significantly differ, regarding their gender, weight or age. Propofol injection pain was less in L and G groups, in comparison with the others (P ≤ 0.001). By analyzing the hemodynamic changes, it was observed that the least amount of change in mean arterial pressure was observed in the paracetamol group. Conclusions: The reduction of propofol injection pain was observed by using medications (in comparison with normal

  4. Desulfocarbo indianensis gen. nov., sp. nov., a benzoate-oxidizing, sulfate-reducing bacterium isolated from water extracted from a coal bed.

    PubMed

    An, Thuy T; Picardal, Flynn W

    2014-08-01

    A novel, strictly anaerobic, sulfate-reducing bacterium, designated strain SCBM(T), was isolated from water extracted from a coal bed in Indiana, USA. The isolate was characterized by a polyphasic taxonomic approach that included phenotypic and genotypic characterizations. Cells of strain SCBM(T) were vibrio-shaped, polarly flagellated, Gram-negative, motile, oxidase-negative and weakly catalase-positive. Growth of strain SCBM(T) was observed at NaCl concentrations ranging from 0 to 300 mM. However, no growth was observed when 1 M or more NaCl was present. Growth was observed at 16-37 °C, with optimal growth at 30 °C. The optimum pH for growth was 7, although growth was observed from pH 6.5 to 8. The doubling time under optimal growth conditions (30 °C, pH 7, 2.5 mM benzoate, 14 mM sulfate) was 2.7 days. Bicarbonate, HEPES, PIPES and MES were effective buffers for growth of strain SCBM(T), but citrate inhibited growth. When sulfate was provided as the electron acceptor, strain SCBM(T) grew autotrophically with hydrogen as the electron donor and heterotrophically on benzoate, formate, acetate, pyruvate, butyrate, fumarate, succinate and palmitate. None of the substrates tested supported fermentative growth. Thiosulfate and sulfate were used as electron acceptors coupled to benzoate oxidation, but sulfite, elemental sulfur, DMSO, anthraquinone 2,6-disulfonate, nitrate, nitrite, ferric citrate, hydrous iron oxide and oxygen were not. The G+C content of genomic DNA was 62.5 mol%. The major cellular fatty acids were anteiso-C(15 : 0) and C(18 : 1)ω7c. Phylogenetic analysis based on 16S rRNA gene sequencing placed strain SCBM(T) into a distinct lineage within the class Deltaproteobacteria. The closest, cultivated phylogenetic relative of strain SCBM(T) was Desulfarculus baarsii DSM 2075(T), with only 91.7% 16S rRNA gene sequence identity. On the basis of phenotypic and genotypic analyses, strain SCBM(T) represents a novel genus and species of sulfate-reducing

  5. Weed-suppressive bacteria to reduce annual grass weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cheatgrass (Bromus tectorum L.), medusahead (Taeniatherum caput-medusae [L.] Nevski) and jointed goatgrass (Aegilops cylindrica L.) are exotic, annual grasses that negatively affect cereal production in cropland; reduce protein-rich forage for cattle; choke out native plants in the shrub-steppe habi...

  6. Activity and phylogenetic diversity of sulfate-reducing microorganisms in low-temperature subsurface fluids within the upper oceanic crust

    PubMed Central

    Robador, Alberto; Jungbluth, Sean P.; LaRowe, Douglas E.; Bowers, Robert M.; Rappé, Michael S.; Amend, Jan P.; Cowen, James P.

    2015-01-01

    The basaltic ocean crust is the largest aquifer system on Earth, yet the rates of biological activity in this environment are unknown. Low-temperature (<100°C) fluid samples were investigated from two borehole observatories in the Juan de Fuca Ridge (JFR) flank, representing a range of upper oceanic basement thermal and geochemical properties. Microbial sulfate reduction rates (SRR) were measured in laboratory incubations with 35S-sulfate over a range of temperatures and the identity of the corresponding sulfate-reducing microorganisms (SRM) was studied by analyzing the sequence diversity of the functional marker dissimilatory (bi)sulfite reductase (dsrAB) gene. We found that microbial sulfate reduction was limited by the decreasing availability of organic electron donors in higher temperature, more altered fluids. Thermodynamic calculations indicate energetic constraints for metabolism, which together with relatively higher cell-specific SRR reveal increased maintenance requirements, consistent with novel species-level dsrAB phylotypes of thermophilic SRM. Our estimates suggest that microbially-mediated sulfate reduction may account for the removal of organic matter in fluids within the upper oceanic crust and underscore the potential quantitative impact of microbial processes in deep subsurface marine crustal fluids on marine and global biogeochemical carbon cycling. PMID:25642212

  7. Betaine reduces the irritating effect of sodium lauryl sulfate on human oral mucosa in vivo.

    PubMed

    Rantanen, Irma; Nicander, Ingrid; Jutila, Kirsti; Ollmar, Stig; Tenovuo, Jorma; Söderling, Eva

    2002-10-01

    Our aim was to evaluate whether betaine has a protective effect during exposure of the human oral mucosa in vivo to sodium lauryl sulfate (SLS) or cocoamidopropylbetaine (CAPB) as measured with a multifrequency electrical impedance spectrometer (EI). Both detergents were used at the concentration of 2.0% w/v with and without 4.0% w/v betaine in distilled water in 20 volunteers, and 0.5% and 1.0% w/v SLS combined with 4.0% w/v betaine in 5 volunteers. EI measurements were taken before application of the test solutions, after their removal, and every 15 min up to 45 min. Both 0.5% and 1% SLS solutions showed a significant reduction in 3 of the 4 indices, indicating mucosal irritation after the 15-min exposure (P < 0.05), whereas 2% SLS did so in all 4 indices (P < 0.001). Betaine had no effect on the detergent-induced decline with either the 2% or the 0.5% SLS solutions. However, when combined with the 1% SLS solution, betaine significantly (P < 0.05) reduced mucosal irritation by abolishing decreases in indices MIX (magnitude index) and IMIX (imaginary part index) and lowering it for PIX (phase index). The 2% CAPB solution showed a significant (P < 0.05) reduction in all 4 indices after the 15-min exposure, but the effect was significantly weaker than that of 2% SLS (P < 0.05). Betaine did not reduce the irritating effect of 2% CAPB. These findings can be used in the development of less irritating products for oral health care. PMID:12418722

  8. MICROBIAL DEGRADATION OF TOLUENE UNDER SULFATE- REDUCING CONDITIONS AND THE INFLUENCE OF IRON ON THE PROCESS

    EPA Science Inventory

    Toluene degradation occurred concomitantly with sulfate reduction in anaerobic microcosms inoculated with contaminated subsurface soil from an aviation fuel storage facility near the Patuxent River (Md.). Similar results were obtained for enrichment cultures in which toluene was ...

  9. Method for reducing sulfate formation during regeneration of hot-gas desulfurization sorbents

    DOEpatents

    Bissett, Larry A.; Strickland, Larry D.; Rockey, John M.

    1994-01-01

    The regeneration of sulfur sorbents having sulfate forming tendencies and used for desulfurizing hot product gas streams such as provided by coal gasification is provided by employing a two-stage regeneration method. Air containing a sub-stoichiometric quantity of oxygen is used in the first stage for substantially fully regenerating the sorbent without sulfate formation and then regeneration of the resulting partially regenerated sorbent is completed in the second stage with air containing a quantity of oxygen slightly greater than the stoichiometric amount adequate to essentially fully regenerate the sorbent. Sulfate formation occurs in only the second stage with the extent of sulfate formation being limited only to the portion of the sulfur species contained by the sorbent after substantially all of the sulfur species have been removed therefrom in the first stage.

  10. Efficiency of inhibitor for biocorrosion influenced by consortium sulfate reducing bacteria on carbon steel

    NASA Astrophysics Data System (ADS)

    Mahat, Nur Akma; Othman, Norinsan Kamil; Sahrani, Fathul Karim

    2015-09-01

    The inhibition efficiency of benzalkonium chloride (BKC) in controlling biocorrosion on the carbon steel surfaces has been investigated. The carbon steel coupons were incubated in the presence of consortium SRB (C-SRB) with and without BKC for the difference medium concentration. The corrosion rate and inhibition efficiency have been evaluated by a weight loss method. The morphology of biofilm C-SRB on the steel surfaces were characterized with variable pressure scanning electron microscopy (VPSEM). The results revealed that BKC exhibits a low corrosion rate, minimizing the cell growth and biofilm development on the carbon steel surfaces.

  11. Efficiency of inhibitor for biocorrosion influenced by consortium sulfate reducing bacteria on carbon steel

    SciTech Connect

    Mahat, Nur Akma; Othman, Norinsan Kamil; Sahrani, Fathul Karim

    2015-09-25

    The inhibition efficiency of benzalkonium chloride (BKC) in controlling biocorrosion on the carbon steel surfaces has been investigated. The carbon steel coupons were incubated in the presence of consortium SRB (C-SRB) with and without BKC for the difference medium concentration. The corrosion rate and inhibition efficiency have been evaluated by a weight loss method. The morphology of biofilm C-SRB on the steel surfaces were characterized with variable pressure scanning electron microscopy (VPSEM). The results revealed that BKC exhibits a low corrosion rate, minimizing the cell growth and biofilm development on the carbon steel surfaces.

  12. EVALUATION OF SULFATE-REDUCING BACTERIA TO PRECIPITATE MERCURY FROM CONTAMINATED GROUNDWATER

    EPA Science Inventory

    Several regions in the Republic of Kazakhstan are contaminated with mercury as a result of releases from industrial plants. Operations at an old chemical plant, "Khimprom", which produced chlorine and alkali in the 1970s - 1990s, resulted in significant pollution of groundwater ...

  13. Characterization of two dissimilatory sulfite reductases from sulfate-reducing bacteria

    NASA Astrophysics Data System (ADS)

    Huynh, B. H.; Moura, I.; Lino, A. R.; Moura, J. J. G.; Legall, J.

    1988-02-01

    Mössbauer, EPR, and biochemical techniques were used to characterize two dissimilatory sulfite reductases: desulforubidin from Desulfovibrio baculatus strain DSM 1743 and desulfoviridin from Desulfovibrio gigas. For each molecule of desulforubidin, there are two sirohemes and four [4Fe-4S] clusters. The [4Fe-4S] clusters are in the diamagnetic 2+ oxidation state. The sirohemes are high-spin ferric (S=5/2) and each siroheme is exchanged-coupled to a [4Fe-4S]2+ cluster. Such an exchange-coupled siroheme-[4Fe-4S] unit has also been found in the assimilatory sulfite reductase from Escherichia coli/1/ and in a low-molecular weight sulfite reductase from Desulfovibrio vulgaris/2/. For each molecule of defulfoviridin, there are two tetrahydroporphyrin groups and four [4Fe-4S]2+ clusters. To our surprise, we discovered that about 80% of the tetrahydroporphyrin groups, however, do not bind iron.

  14. Microbially induced separation of quartz from hematite using sulfate reducing bacteria.

    PubMed

    Prakasan, M R Sabari; Natarajan, K A

    2010-07-01

    Cells and metabolic products of Desulfovibrio desulfuricans were successfully used to separate quartz from hematite through environmentally benign microbially induced flotation. Bacterial metabolic products such as extracellular proteins and polysaccharides were isolated from both unadapted and mineral-adapted bacterial metabolite and their basic characteristics were studied in order to get insight into the changes brought about on bioreagents during adaptation. Interaction between bacterial cells and metabolites with minerals like hematite and quartz brought about significant surface-chemical changes on both the minerals. Quartz was rendered more hydrophobic, while hematite became more hydrophilic after biotreatment. The predominance of bacterial polysaccharides on interacted hematite and of proteins on quartz was responsible for the above surface-chemical changes, as attested through adsorption studies. Surface-chemical changes were also observed on bacterial cells after adaptation to the above minerals. Selective separation of quartz from hematite was achieved through interaction with quartz-adapted bacterial cells and metabolite. Mineral-specific proteins secreted by quartz-adapted cells were responsible for conferment of hydrophobicity on quartz resulting in enhanced separation from hematite through flotation. PMID:20347277

  15. Effects of borax treatment on hydrogen sulfide emissions and sulfate reducing bacteria in stored swine manure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Malodorous compounds and emissions produced from stored swine manure can pose both environmental and health issues. These nuisance odors largely result from compounds such as sulfides, volatile fatty acids, and phenols, which are produced as a result of anaerobic digestion of materials present in t...

  16. Anaerobic biodegradation of nonylphenol in river sediment under nitrate- or sulfate-reducing conditions and associated bacterial community.

    PubMed

    Wang, Zhao; Yang, Yuyin; Dai, Yu; Xie, Shuguang

    2015-04-01

    Nonylphenol (NP) is a commonly detected pollutant in aquatic ecosystem and can be harmful to aquatic organisms. Anaerobic degradation is of great importance for the clean-up of NP in sediment. However, information on anaerobic NP biodegradation in the environment is still very limited. The present study investigated the shift in bacterial community structure associated with NP degradation in river sediment microcosms under nitrate- or sulfate-reducing conditions. Nearly 80% of NP (100 mg kg(-1)) could be removed under these two anaerobic conditions after 90 or 110 days' incubation. Illumina MiSeq sequencing analysis indicated that Proteobacteria, Firmicutes, Bacteroidetes and Chloroflexi became the dominant phylum groups with NP biodegradation. The proportion of Gammaproteobacteria, Deltaproteobacteria and Choloroflexi showed a marked increase in nitrate-reducing microcosm, while Gammaproteobacteria and Firmicutes in sulfate-reducing microcosm. Moreover, sediment bacterial diversity changed with NP biodegradation, which was dependent on type of electron acceptor. PMID:25590825

  17. Function of Periplasmic Hydrogenases in the Sulfate-ReducingBacterium Desulfovibrio vulgaris Hildenborough

    SciTech Connect

    Caffrey, Sean M.; Park, Hyung-Soo; Voordouw, Johanna K.; He,Zhili; Zhou, Jizhong; Voordouw, Gerrit

    2007-09-24

    The sulfate-reducing bacterium Desulfovibrio vulgarisHildenborough possesses four periplasmic hydrogenases to facilitate theoxidation of molecular hydrogen. These include an [Fe]hydrogenase, an[NiFeSe]hydrogenase, and two [NiFe]hydrogenases encoded by the hyd,hys, hyn1, and hyn2 genes, respectively. In order to understand theircellular functions, we have compared the growth rates of existing (hydand hyn1) and newly constructed (hys and hyn-1 hyd) mutants to those ofthe wild type in defined media in which lactate or hydrogen at either 5or 50 percent (vol/vol) was used as the sole electron donor for sulfatereduction. Only strains missing the [Fe]hydrogenase were significantlyaffected during growth with lactate or with 50 percent (vol/vol) hydrogenas the sole electron donor. When the cells were grown at low (5 percent[vol/vol]) hydrogen concentrations, those missing the [NiFeSe]hydrogenase suffered the greatest impairment. The growth rate datacorrelated strongly with gene expression results obtained from microarrayhybridizations and real-time PCR using mRNA extracted from cells grownunder the three conditions. Expression of the hys genes followed theorder 5 percent hydrogen>50 percent hydrogen>lactate, whereasexpression of the hyd genes followed the reverse order. These resultssuggest that growth with lactate and 50 percent hydrogen is associatedwith high intracellular hydrogen concentrations, which are best capturedby the higher activity, lower affinity [Fe]hydrogenase. In contrast,growth with 5 percent hydrogen is associated with a low intracellularhydrogen concentration, requiring the lower activity, higher affinity[NiFeSe]hydrogenase.

  18. Changing Microspatial Patterns of Sulfate-Reducing Microorganisms (SRM) during Cycling of Marine Stromatolite Mats

    PubMed Central

    Petrisor, Alexandru I.; Szyjka, Sandra; Kawaguchi, Tomohiro; Visscher, Pieter T.; Norman, Robert Sean; Decho, Alan W.

    2014-01-01

    Microspatial arrangements of sulfate-reducing microorganisms (SRM) in surface microbial mats (~1.5 mm) forming open marine stromatolites were investigated. Previous research revealed three different mat types associated with these stromatolites, each with a unique petrographic signature. Here we focused on comparing “non-lithifying” (Type-1) and “lithifying” (Type-2) mats. Our results revealed three major trends: (1) Molecular typing using the dsrA probe revealed a shift in the SRM community composition between Type-1 and Type-2 mats. Fluorescence in-situ hybridization (FISH) coupled to confocal scanning-laser microscopy (CSLM)-based image analyses, and 35SO4 2−-silver foil patterns showed that SRM were present in surfaces of both mat types, but in significantly (p < 0.05) higher abundances in Type-2 mats. Over 85% of SRM cells in the top 0.5 mm of Type-2 mats were contained in a dense 130 μm thick horizontal layer comprised of clusters of varying sizes; (2) Microspatial mapping revealed that locations of SRM and CaCO3 precipitation were significantly correlated (p < 0.05); (3) Extracts from Type-2 mats contained acylhomoserine-lactones (C4-, C6-, oxo-C6 C7-, C8-, C10-, C12-, C14-AHLs) involved in cell-cell communication. Similar AHLs were produced by SRM mat-isolates. These trends suggest that development of a microspatially-organized SRM community is closely-associated with the hallmark transition of stromatolite surface mats from a non-lithifying to a lithifying state. PMID:24413754

  19. Distribution, Activities, and Interactions of Methanogens and Sulfate-Reducing Prokaryotes in the Florida Everglades

    PubMed Central

    Bae, Hee-Sung; Holmes, M. Elizabeth; Chanton, Jeffrey P.; Reddy, K. Ramesh

    2015-01-01

    To gain insight into the mechanisms controlling methanogenic pathways in the Florida Everglades, the distribution and functional activities of methanogens and sulfate-reducing prokaryotes (SRPs) were investigated in soils (0 to 2 or 0 to 4 cm depth) across the well-documented nutrient gradient in the water conservation areas (WCAs) caused by runoff from the adjacent Everglades Agricultural Area. The methyl coenzyme M reductase gene (mcrA) sequences that were retrieved from WCA-2A, an area with relatively high concentrations of SO42− (≥39 μM), indicated that methanogens inhabiting this area were broadly distributed within the orders Methanomicrobiales, Methanosarcinales, Methanocellales, Methanobacteriales, and Methanomassiliicoccales. In more than 3 years of monitoring, quantitative PCR (qPCR) using newly designed group-specific primers revealed that the hydrogenotrophic Methanomicrobiales were more numerous than the Methanosaetaceae obligatory acetotrophs in SO42−-rich areas of WCA-2A, while the Methanosaetaceae were dominant over the Methanomicrobiales in WCA-3A (with relatively low SO42− concentrations; ≤4 μM). qPCR of dsrB sequences also indicated that SRPs are present at greater numbers than methanogens in the WCAs. In an incubation study with WCA-2A soils, addition of MoO42− (a specific inhibitor of SRP activity) resulted in increased methane production rates, lower apparent fractionation factors [αapp; defined as (amount of δ13CO2 + 1,000)/(amount of δ13CH4 + 1,000)], and higher Methanosaetaceae mcrA transcript levels compared to those for the controls without MoO42−. These results indicate that SRPs play crucial roles in controlling methanogenic pathways and in shaping the structures of methanogen assemblages as a function of position along the nutrient gradient. PMID:26276115

  20. Distribution, activities, and interactions of methanogens and sulfate-reducing prokaryotes in the Florida Everglades.

    PubMed

    Bae, Hee-Sung; Holmes, M Elizabeth; Chanton, Jeffrey P; Reddy, K Ramesh; Ogram, Andrew

    2015-11-01

    To gain insight into the mechanisms controlling methanogenic pathways in the Florida Everglades, the distribution and functional activities of methanogens and sulfate-reducing prokaryotes (SRPs) were investigated in soils (0 to 2 or 0 to 4 cm depth) across the well-documented nutrient gradient in the water conservation areas (WCAs) caused by runoff from the adjacent Everglades Agricultural Area. The methyl coenzyme M reductase gene (mcrA) sequences that were retrieved from WCA-2A, an area with relatively high concentrations of SO4 (2-) (≥39 μM), indicated that methanogens inhabiting this area were broadly distributed within the orders Methanomicrobiales, Methanosarcinales, Methanocellales, Methanobacteriales, and Methanomassiliicoccales. In more than 3 years of monitoring, quantitative PCR (qPCR) using newly designed group-specific primers revealed that the hydrogenotrophic Methanomicrobiales were more numerous than the Methanosaetaceae obligatory acetotrophs in SO4 (2-)-rich areas of WCA-2A, while the Methanosaetaceae were dominant over the Methanomicrobiales in WCA-3A (with relatively low SO4 (2-) concentrations; ≤4 μM). qPCR of dsrB sequences also indicated that SRPs are present at greater numbers than methanogens in the WCAs. In an incubation study with WCA-2A soils, addition of MoO4 (2-) (a specific inhibitor of SRP activity) resulted in increased methane production rates, lower apparent fractionation factors [αapp; defined as (amount of δ(13)CO2 + 1,000)/(amount of δ(13)CH4 + 1,000)], and higher Methanosaetaceae mcrA transcript levels compared to those for the controls without MoO4 (2-). These results indicate that SRPs play crucial roles in controlling methanogenic pathways and in shaping the structures of methanogen assemblages as a function of position along the nutrient gradient. PMID:26276115

  1. Methylmercury decomposition in sediments and bacterial cultures: Involvement of methanogens and sulfate reducers in oxidative demethylation

    USGS Publications Warehouse

    Oremland, R.S.; Culbertson, C.W.; Winfrey, M.R.

    1991-01-01

    Demethylation of monomethylmercury in freshwater and estuarine sediments and in bacterial cultures was investigated with 14CH3HgI. Under anaerobiosis, results with inhibitors indicated partial involvement of both sulfate reducers and methanogens, the former dominating estuarine sediments, while both were active in freshwaters. Aerobes were the most significant demethylators in estuarine sediments, but were unimportant in freshwater sediments. Products of anaerobic demethylation were mainly 14CO2 as well as lesser amounts of 14CH4. Acetogenic activity resulted in fixation of some 14CO2 produced from 14CH3HgI into acetate. Aerobic demethylation in estuarine sediments produced only 14CH4, while aerobic demethylation in freshwater sediments produced small amounts of both 14CH4 and 14CO2. Two species of Desulfovibrio produced only traces of 14CH4 from 14CH3HgI, while a culture of a methylotrophic methanogen formed traces of 14CO2 and 14CH4 when grown on trimethylamine in the presence of the 14CH3HgI. These results indicate that both aerobes and anaerobes demethylate mercury in sediments, but that either group may dominate in a particular sediment type. Aerobic demethylation in the estuarine sediments appeared to proceed by the previously characterized organomercurial-lyase pathway, because methane was the sole product. However, aerobic demethylation in freshwater sediments as well as anaerobic demethylation in all sediments studied produced primarily carbon dioxide. This indicates the presence of an oxidative pathway, possibly one in which methylmercury serves as an analog of one-carbon substrates.

  2. Reducing phosphorus runoff and inhibiting ammonia loss from poultry manure with aluminum sulfate

    SciTech Connect

    Moore, P.A. Jr.; Daniel, T.C.; Edwards, D.R.

    2000-02-01

    Applications of aluminum sulfate (Al{sub 2}(SO{sub 4}){sub 3} {center_dot} 14H{sub 2}O), commonly referred to as alum, to poultry litter have been shown to decrease P runoff from lands fertilized with litter and to inhibit NH{sub 3} volatilization. The objectives of this study were to evaluate the effects of alum applications in commercial broiler houses on: (1) NH{sub 3} volatilization (in-house), (2) poultry production, (3) litter chemistry, and (4) P runoff following litter application. Two farms were used for this study: one had six poultry houses and the other had four. The litter in half of the houses at each farm was treated with alum; the other houses were controls. Alum was applied at a rate of 1,816 kg/house, which corresponded to 0.091 kg/bird. Each year the houses were cleaned in the spring and the litter was broadcast onto paired watersheds in tall fescue at each farm. Results from this study showed that alum applications lowered the litter pH, particularly during the first 3 to 4 wk of each growout. Reductions in litter pH resulted in less NH{sub 3} volatilization, which led to reductions in atmospheric NH{sub 3} in the alum-treated houses. Broilers grown on alum-treated litter were significantly heavier than controls (1.73 kg vs. 1.66 kg). Soluble reactive phosphorus (SRP) concentrations in runoff from pastures fertilized with alum-treated litter averaged 73% lower than that from normal litter throughout a 3-yr period. These results indicate that alum-treatment of poultry litter is a very effective best management practice that reduces nonpoint source pollution while it increases agricultural productivity.

  3. Reduced molecular size and altered disaccharide composition of cerebral chondroitin sulfate upon Alzheimer's pathogenesis in mice.

    PubMed

    Zhang, Zui; Ohtake-Niimi, Shiori; Kadomatsu, Kenji; Uchimura, Kenji

    2016-08-01

    Alzheimer's disease (AD) is a progressive disorder leading to cognitive impairment and neuronal loss. Cerebral extracellular accumulation and deposition of amyloid ß plaques is a pathological hallmark of AD. Chondroitin sulfate (CS) is an extracellular component abundant in the brain. CS is a sulfated glycosaminoglycan covalently attached to a core protein, forming chondroitin sulfate proteoglycan. The structure of CS is heterogeneous with sulfation modification and elongation of the chain. The structural diversity of CS allows it to play various roles in the brain. Increasing evidence has shown that CS promotes aggregation of amyloid ß peptides into higher-order species such as insoluble amyloid ß fibrils. Difficulties in the structural analysis of brain CS, as well as its heterogeneity, limit the study of potential roles of CS in AD pathology. Here we established a microanalysis method with reversed-phase ion-pair high performance liquid chromatography and found that CS in the brains of Tg2576 AD model mice show a lower molecular size and an increased ratio of CS-B motif di-sulfated disaccharide. Our findings provide insight into the structural changes of cerebral CS upon Alzheimer's pathogenesis. PMID:27578913

  4. Hydrocarbon activation under sulfate-reducing and methanogenic conditions proceeds by different mechanisms.

    NASA Astrophysics Data System (ADS)

    Head, Ian; Gray, Neil; Aitken, Caroline; Sherry, Angela; Jones, Martin; Larter, Stephen

    2010-05-01

    Microbial degradation of alkanes typically involves their conversion to fatty acids which are then catabolised by beta-oxidation. The critical step in this process is activation of the hydrocarbon. Under oxic conditions this is catalyzed by monooxygenase enzymes with the formation of long chain alcohols. In the absence of oxygen alternative alkane activation mechanisms have been observed or proposed. Fumarate addition to alkanes to form alkyl succinates is considered a central process in anaerobic hydrocarbon degradation. Comparative studies of crude oil degradation under sulphate-reducing and methanogenic conditions revealed distinctive patterns of compound class removal and metabolite formation. Alkyl succinates derived from C7 to C26 n-alkanes and branched chain alkanes were found in abundance in sulfate-reducing systems but these were not detected during methanogenic crude oil degradation. Only one other mechanism of alkane activation has been elucidated to date. This involves addition of carbon derived from bicarbonate/CO2 to C-3 of an alkane chain to form a 2-ethylalkane with subsequent removal of the ethyl group leading to the formation of a fatty acid 1 carbon shorter than the original alkane. 2-ethylalkanes have never been detected as metabolites of anaerobic alkane degradation and were not detected in crude oil-degrading methanogenic systems. Due to the range of alkanes present in crude oil it was not possible to infer the generation of C-odd acids from C-even alkanes which is characteristic of the C-3 carboxylation mechanism. Furthermore genes homologous to alkysuccinate synthetases were not detected in the methanogenic hydrocarbon degrading community by pyrosequencing of total DNA extracted from methanogenic enrichments cultures. beta-oxidation genes were detected and intriguingly, alcohol and aldehyde dehydrogenase genes were present. This offers the possibility that alkane activation in the methanogenic system does not proceed via acid metabolites

  5. Thermophilic nitrate-reducing microorganisms prevent sulfate reduction in cold marine sediments incubated at high temperature

    NASA Astrophysics Data System (ADS)

    Nepomnyashchaya, Yana; Rezende, Julia; Hubert, Casey

    2014-05-01

    Hydrogen sulphide produced during metabolism of sulphate-reducing microorganisms (SRM) is toxic, corrosive and causes detrimental oil reservoir souring. During secondary oil recovery, injecting oil reservoirs with seawater that is rich in sulphate and that also cools high temperature formations provides favourable growth conditions for SRM. Nitrate addition can prevent metabolism of SRM by stimulating nitrate-reducing microorganisms (NRM). The investigations of thermophilic NRM are needed to develop mechanisms to control the metabolism of SRM in high temperature oil field ecosystems. We therefore established a model system consisting of enrichment cultures of cold surface marine sediments from the Baltic Sea (Aarhus Bay) that were incubated at 60°C. Enrichments contained 25 mM nitrate and 40 mM sulphate as potential electron acceptors, and a mixture of the organic substrates acetate, lactate, propionate, butyrate (5 mM each) and yeast extract (0.01%) as potential carbon sources and electron donors. Slurries were incubated at 60°C both with and without initial pasteurization at 80°C for 2 hours. In the enrichments containing both nitrate and sulphate, the concentration of nitrate decreased indicating metabolic activity of NRM. After a four-hour lag phase the rate of nitrate reduction increased and the concentration of nitrate dropped to zero after 10 hours of incubation. The concentration of nitrite increased as the reduction of nitrate progressed and reached 16.3 mM after 12 hours, before being consumed and falling to 4.4 mM after 19-day of incubation. No evidence for sulphate reduction was observed in these cultures during the 19-day incubation period. In contrast, the concentration of sulphate decreased up to 50% after one week incubation in controls containing only sulphate but no nitrate. Similar sulfate reduction rates were seen in the pasteurized controls suggesting the presence of heat resistant SRM, whereas nitrate reduction rates were lower in the

  6. Optimization of peptide nucleic acid fluorescence in situ hybridization (PNA-FISH) for the detection of bacteria: The effect of pH, dextran sulfate and probe concentration.

    PubMed

    Rocha, Rui; Santos, Rita S; Madureira, Pedro; Almeida, Carina; Azevedo, Nuno F

    2016-05-20

    Fluorescence in situ hybridization (FISH) is a molecular technique widely used for the detection and characterization of microbial populations. FISH is affected by a wide variety of abiotic and biotic variables and the way they interact with each other. This is translated into a wide variability of FISH procedures found in the literature. The aim of this work is to systematically study the effects of pH, dextran sulfate and probe concentration in the FISH protocol, using a general peptide nucleic acid (PNA) probe for the Eubacteria domain. For this, response surface methodology was used to optimize these 3 PNA-FISH parameters for Gram-negative (Escherichia coli and Pseudomonas fluorescens) and Gram-positive species (Listeria innocua, Staphylococcus epidermidis and Bacillus cereus). The obtained results show that a probe concentration higher than 300nM is favorable for both groups. Interestingly, a clear distinction between the two groups regarding the optimal pH and dextran sulfate concentration was found: a high pH (approx. 10), combined with lower dextran sulfate concentration (approx. 2% [w/v]) for Gram-negative species and near-neutral pH (approx. 8), together with higher dextran sulfate concentrations (approx. 10% [w/v]) for Gram-positive species. This behavior seems to result from an interplay between pH and dextran sulfate and their ability to influence probe concentration and diffusion towards the rRNA target. This study shows that, for an optimum hybridization protocol, dextran sulfate and pH should be adjusted according to the target bacteria. PMID:27021959

  7. Effects of temperature on anaerobic decomposition of high-molecular weight organic matter under sulfate-reducing conditions

    NASA Astrophysics Data System (ADS)

    Matsui, Takato; Kojima, Hisaya; Fukui, Manabu

    2013-03-01

    Most sedimentary mineralization occurs along coasts under anaerobic conditions. In the absence of oxygen, high-molecular weight organic matter in marine sediments is gradually decomposed by hydrolysis, fermentation and sulfate reduction. Because of the different responses of the respective steps to temperature, degradation may be specifically slowed or stopped in certain step. To evaluate the effect of temperature on cellobiose degradation, culture experiments were performed at six different temperatures (3 °C, 8 °C, 13 °C, 18 °C, 23 °C, and 28 °C) under sulfate-reducing conditions. This study measured the concentrations of sulfide, dissolved organic carbon (DOC), and organic acids during that degradation. Degradation patterns were divided into three temperature groups: 3 °C, 8/13 °C, and 18/23/28 °C. The decrease in DOC proceeded in two steps, except at 3 °C. The length of the stagnant phase separating these two steps differed greatly between temperatures of 8/13 °C and 18/23/28 °C. In the first step, organic carbon was consumed by hydrolysis, fermentation and sulfate reduction. In the second step, acetate accumulated during the first step was oxidized by sulfate reduction. Bacterial communities in the cultures were analyzed by denaturing gradient gel electrophoresis (DGGE); the major differences among the three temperature groups were attributed to shifts in acetate-using sulfate reducers of the genus Desulfobacter. This suggests that temperature characteristics of dominant acetate oxidizers are important factors in determining the response of carbon flow in coastal marine sediments in relation to the changes in temperature.

  8. Probiotic bacteria lactobacillus and bifidobacterium attenuate inflammation in dextran sulfate sodium-induced experimental colitis in mice.

    PubMed

    Toumi, R; Soufli, I; Rafa, H; Belkhelfa, M; Biad, A; Touil-Boukoffa, C

    2014-01-01

    It is widely accepted that inflammatory Bowel disease (IBD) arises from a dysregulated mucosal immune response to the enteric microbiota in the gut of a genetically susceptible individual. No definitive therapies are available for this inflammatory disorder. Therefore it became imperative to develop new strategies for treating this disease. Probiotics have emerged as a potential new therapeutic strategy for IBD, however their exact mechanisms of action is still poorly defined. In this study, we address the potential effect of a probiotic cocktail (Ultrabiotique®) composed of four live bacterial strains (L. acidophilus, L. plantarum, B. lactis and B.breve) to promote recovery from acute colitis. Probiotic was given to mice by oral gavage after the onset of colitis and the establishment of dextran sulfate sodium (DSS)-induced intestinal injury. Clinical parameters were monitored daily, histological scores of colitis and the production of nitric oxide (NO) and interferon-γ (IFN-γ) were determined. In addition, TLR4, NF-κB and iNOS colonic expression were examined. Probiotic treatment ameliorated clinical symptoms and histological scores. NO and IFN-γ production in plasma were decreased by probiotic. These results were associated with reduced TLR4, iNOS and NF-кB expression in colonic tissue. In conclusion, probiotic exerted anti-inflammatory effects and contributed to a rapid recovery of DSS-induced acute colitis. PMID:25572742

  9. Genome Sequence of the Piezophilic, Mesophilic Sulfate-Reducing Bacterium Desulfovibrio indicus J2T

    PubMed Central

    Maignien, Lois; Shao, Zongze; Alain, Karine

    2016-01-01

    The complete genome sequence of Desulfovibrio indicus J2T, a member of the family Desulfovibrionaceae, consists of 3,966,573-bp in one contig and encodes 3,461 predicted genes, 5 noncoding RNAs, 3 rRNAs operons, and 52 tRNA-encoding genes. The genome is consistent with a heterotrophic, anaerobic lifestyle including the sulfate reduction pathway. PMID:27056223

  10. Can microbially-generated hydrogen sulfide account for the rates of U(VI) reduction by a sulfate-reducing bacterium?

    SciTech Connect

    Boonchayaanant, Benjaporn; Gu, Baohua; Wang, Wei; Ortiz, Monica E; Criddle, Craig

    2010-01-01

    In situ remediation of uranium contaminated soil and groundwater is attractive because a diverse range of microbial and abiotic processes reduce soluble and mobile U(VI) to sparingly soluble and immobile U(IV). Often these processes are linked. Sulfate-reducing bacteria (SRB), for example, enzymatically reduce U(VI) to U(IV), but they also produce hydrogen sulfide that can itself reduce U(VI). This study evaluated the relative importance of these processes for Desulfovibrio aerotolerans, a SRB isolated from a U(VI)-contaminated site. For the conditions evaluated, the observed rate of SRB-mediated U(VI) reduction can be explained by the abiotic reaction of U(VI) with the microbially-generated H{sub 2}S. The presence of trace ferrous iron appeared to enhance the extent of hydrogen sulfide-mediated U(VI) reduction at 5 mM bicarbonate, but had no clear effect at 15 mM. During the hydrogen sulfide-mediated reduction of U(VI), a floc formed containing uranium and sulfur. U(VI) sequestered in the floc was not available for further reduction.

  11. A New Type of Metal-Binding Site in Cobalt- And Zinc-Containing Adenylate Kinases Isolated From Sulfate-Reducers D. Gigas And D. Desulfuricans ATCC 27774

    SciTech Connect

    Gavel, O.Y.; Bursakov, S.A.; Rocco, G.Di; Trincao, J.; Pickering, I.J.; George, G.N.; Calvete, J.J.; Brondino, C.; Pereira, A.S.; Lampreia, J.; Tavares, P.; Moura, J.J.G.; Moura, I.

    2009-05-18

    Adenylate kinase (AK) mediates the reversible transfer of phosphate groups between the adenylate nucleotides and contributes to the maintenance of their constant cellular level, necessary for energy metabolism and nucleic acid synthesis. The AK were purified from crude extracts of two sulfate-reducing bacteria (SRB), Desulfovibrio (D.) gigas NCIB 9332 and Desulfovibrio desulfuricans ATCC 27774, and biochemically and spectroscopically characterized in the native and fully cobalt- or zinc-substituted forms. These are the first reported adenylate kinases that bind either zinc or cobalt and are related to the subgroup of metal-containing AK found, in most cases, in Gram-positive bacteria. The electronic absorption spectrum is consistent with tetrahedral coordinated cobalt, predominantly via sulfur ligands, and is supported by EPR. The involvement of three cysteines in cobalt or zinc coordination was confirmed by chemical methods. Extended X-ray absorption fine structure (EXAFS) indicate that cobalt or zinc are bound by three cysteine residues and one histidine in the metal-binding site of the 'LID' domain. The sequence {sup 129}Cys-X{sub 5}-His-X{sub 15}-Cys-X{sub 2}-Cys of the AK from D. gigas is involved in metal coordination and represents a new type of binding motif that differs from other known zinc-binding sites of AK. Cobalt and zinc play a structural role in stabilizing the LID domain.

  12. Reductive Precipitation of Gold by Dissimilatory Fe(III)-Reducing Bacteria and Archaea

    PubMed Central

    Kashefi, Kazem; Tor, Jason M.; Nevin, Kelly P.; Lovley, Derek R.

    2001-01-01

    Studies with a diversity of hyperthermophilic and mesophilic dissimilatory Fe(III)-reducing Bacteria and Archaea demonstrated that some of these organisms are capable of precipitating gold by reducing Au(III) to Au(0) with hydrogen as the electron donor. These studies suggest that models for the formation of gold deposits in both hydrothermal and cooler environments should consider the possibility that dissimilatory metal-reducing microorganisms can reductively precipitate gold from solution. PMID:11425752

  13. Toward a rigorous network of protein-protein interactions of the model sulfate reducer Desulfovibrio vulgaris Hildenborough

    SciTech Connect

    Chhabra, S.R.; Joachimiak, M.P.; Petzold, C.J.; Zane, G.M.; Price, M.N.; Gaucher, S.; Reveco, S.A.; Fok, V.; Johanson, A.R.; Batth, T.S.; Singer, M.; Chandonia, J.M.; Joyner, D.; Hazen, T.C.; Arkin, A.P.; Wall, J.D.; Singh, A.K.; Keasling, J.D.

    2011-05-01

    Protein–protein interactions offer an insight into cellular processes beyond what may be obtained by the quantitative functional genomics tools of proteomics and transcriptomics. The aforementioned tools have been extensively applied to study E. coli and other aerobes and more recently to study the stress response behavior of Desulfovibrio 5 vulgaris Hildenborough, a model anaerobe and sulfate reducer. In this paper we present the first attempt to identify protein-protein interactions in an obligate anaerobic bacterium. We used suicide vector-assisted chromosomal modification of 12 open reading frames encoded by this sulfate reducer to append an eight amino acid affinity tag to the carboxy-terminus of the chosen proteins. Three biological replicates of the 10 ‘pulled-down’ proteins were separated and analyzed using liquid chromatography-mass spectrometry. Replicate agreement ranged between 35% and 69%. An interaction network among 12 bait and 90 prey proteins was reconstructed based on 134 bait-prey interactions computationally identified to be of high confidence. We discuss the biological significance of several unique metabolic features of D. vulgaris revealed by this protein-protein interaction data 15 and protein modifications that were observed. These include the distinct role of the putative carbon monoxide-induced hydrogenase, unique electron transfer routes associated with different oxidoreductases, and the possible role of methylation in regulating sulfate reduction.

  14. ACETOGENIC AND SULPHATE-REDUCING BACTERIA INHABITING THE RHIZOPLANE AND DEEP CORTEX CELLS OF THE SEAGRASS HALODULE WRIGHTII

    EPA Science Inventory

    Recent declines in sea grass distribution underscore the importance of understanding microbial community structure-function relationships in sea grass rhizosphere that might affect the viability of these plants. Phospholipid fatty acid analyses showed that sulfate-reducing bacter...

  15. Genome Sequence of the Piezophilic, Mesophilic Sulfate-Reducing Bacterium Desulfovibrio indicus J2T.

    PubMed

    Cao, Junwei; Maignien, Lois; Shao, Zongze; Alain, Karine; Jebbar, Mohamed

    2016-01-01

    The complete genome sequence ofDesulfovibrio indicusJ2(T), a member of the familyDesulfovibrionaceae, consists of 3,966,573-bp in one contig and encodes 3,461 predicted genes, 5 noncoding RNAs, 3 rRNAs operons, and 52 tRNA-encoding genes. The genome is consistent with a heterotrophic, anaerobic lifestyle including the sulfate reduction pathway. PMID:27056223

  16. Three manganese oxide-rich marine sediments harbor similar communities of acetate-oxidizing manganese-reducing bacteria.

    PubMed

    Vandieken, Verona; Pester, Michael; Finke, Niko; Hyun, Jung-Ho; Friedrich, Michael W; Loy, Alexander; Thamdrup, Bo

    2012-11-01

    Dissimilatory manganese reduction dominates anaerobic carbon oxidation in marine sediments with high manganese oxide concentrations, but the microorganisms responsible for this process are largely unknown. In this study, the acetate-utilizing manganese-reducing microbiota in geographically well-separated, manganese oxide-rich sediments from Gullmar Fjord (Sweden), Skagerrak (Norway) and Ulleung Basin (Korea) were analyzed by 16S rRNA-stable isotope probing (SIP). Manganese reduction was the prevailing terminal electron-accepting process in anoxic incubations of surface sediments, and even the addition of acetate stimulated neither iron nor sulfate reduction. The three geographically distinct sediments harbored surprisingly similar communities of acetate-utilizing manganese-reducing bacteria: 16S rRNA of members of the genera Colwellia and Arcobacter and of novel genera within the Oceanospirillaceae and Alteromonadales were detected in heavy RNA-SIP fractions from these three sediments. Most probable number (MPN) analysis yielded up to 10(6) acetate-utilizing manganese-reducing cells cm(-3) in Gullmar Fjord sediment. A 16S rRNA gene clone library that was established from the highest MPN dilutions was dominated by sequences of Colwellia and Arcobacter species and members of the Oceanospirillaceae, supporting the obtained RNA-SIP results. In conclusion, these findings strongly suggest that (i) acetate-dependent manganese reduction in manganese oxide-rich sediments is catalyzed by members of taxa (Arcobacter, Colwellia and Oceanospirillaceae) previously not known to possess this physiological function, (ii) similar acetate-utilizing manganese reducers thrive in geographically distinct regions and (iii) the identified manganese reducers differ greatly from the extensively explored iron reducers in marine sediments. PMID:22572639

  17. Ecophysiological Evidence that Achromatium oxaliferum Is Responsible for the Oxidation of Reduced Sulfur Species to Sulfate in a Freshwater Sediment

    PubMed Central

    Gray, N. D.; Pickup, R. W.; Jones, J. G.; Head, I. M.

    1997-01-01

    Achromatium oxaliferum is a large, morphologically conspicuous, sediment-dwelling bacterium. The organism has yet to be cultured in the laboratory, and very little is known about its physiology. The presence of intracellular inclusions of calcite and sulfur have given rise to speculation that the bacterium is involved in the carbon and sulfur cycles in the sediments where it is found. Depth profiles of oxygen concentration and A. oxaliferum cell numbers in a freshwater sediment revealed that the A. oxaliferum population spanned the oxic-anoxic boundary in the top 3 to 4 cm of sediments. Some of the A. oxaliferum cells resided at depths where no oxygen was detectable, suggesting that these cells may be capable of anaerobic metabolism. The distributions of solid-phase and dissolved inorganic sulfur species in the sediment revealed that A. oxaliferum was most abundant where sulfur cycling was most intense. The sediment was characterized by low concentrations of free sulfide. However, a comparison of sulfate reduction rates in sediment cores incubated with either oxic or anoxic overlying water indicated that the oxidative and reductive components of the sulfur cycle were tightly coupled in the A. oxaliferum-bearing sediment. A positive correlation between pore water sulfate concentration and A. oxaliferum numbers was observed in field data collected over an 18-month period, suggesting a possible link between A. oxaliferum numbers and the oxidation of reduced sulfur species to sulfate. The field data were supported by laboratory incubation experiments in which sodium molybdate-treated sediment cores were augmented with highly purified suspensions of A. oxaliferum cells. Under oxic conditions, rates of sulfate production in the presence of sodium molybdate were found to correlate strongly with the number of cells added to sediment cores, providing further evidence for a role for A. oxaliferum in the oxidation of reduced sulfur. PMID:16535604

  18. Borax and octabor treatment of stored swine manure to reduce sulfate reducing bacteria and hydrogen sulfide emissions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Odorous gas emissions from stored swine manure are becoming serious environmental and health issues as the livestock industry becomes more specialized, concentrated, and industrialized. These nuisance gasses include hydrogen sulfide (H2S), ammonia, and methane, which are produced as a result of ana...

  19. Subcellular localization of proteins in the anaerobic sulfate reducer Desulfovibrio vulgaris via SNAP-tag labeling and photoconversion

    SciTech Connect

    Gorur, A.; Leung, C. M.; Jorgens, D.; Tauscher, A.; Remis, J. P.; Ball, D. A.; Chhabra, S.; Fok, V.; Geller, J. T.; Singer, M.; Hazen, T. C.; Juba, T.; Elias, D.; Wall, J.; Biggin, M.; Downing, K. H.; Auer, M.

    2010-06-01

    Systems Biology studies the temporal and spatial 3D distribution of macromolecular complexes with the aim that such knowledge will allow more accurate modeling of biological function and will allow mathematical prediction of cellular behavior. However, in order to accomplish accurate modeling precise knowledge of spatial 3D organization and distribution inside cells is necessary. And while a number of macromolecular complexes may be identified by its 3D structure and molecular characteristics alone, the overwhelming number of proteins will need to be localized using a reporter tag. GFP and its derivatives (XFPs) have been traditionally employed for subcelllar localization using photoconversion approaches, but this approach cannot be taken for obligate anaerobic bacteria, where the intolerance towards oxygen prevents XFP approaches. As part of the GTL-funded PCAP project (now ENIGMA) genetic tools have been developed for the anaerobe sulfate reducer Desulfovibrio vulgaris that allow the high-throughput generation of tagged-protein mutant strains, with a focus on the commercially available SNAP-tag cell system (New England Biolabs, Ipswich, MA), which is based on a modified O6-alkylguanine-DNA alkyltransferase (AGT) tag, that has a dead-end reaction with a modified O6-benzylguanine (BG) derivative and has been shown to function under anaerobic conditions. After initial challenges with respect to variability, robustness and specificity of the labeling signal we have optimized the labeling. Over the last year, as a result of the optimized labeling protocol, we now obtain robust labeling of 20 out of 31 SNAP strains. Labeling for 13 strains were confirmed at least five times. We have also successfully performed photoconversion on 5 of these 13 strains, with distinct labeling patterns for different strains. For example, DsrC robustly localizes to the periplasmic portion of the inner membrane, where as a DNA-binding protein localizes to the center of the cell, where the

  20. Effects of Lead and Mercury on Sulfate-Reducing Bacterial Activity in a Biological Process for Flue Gas Desulfurization Wastewater Treatment

    PubMed Central

    Zhang, Liang; Lin, Xiaojuan; Wang, Jinting; Jiang, Feng; Wei, Li; Chen, Guanghao; Hao, Xiaodi

    2016-01-01

    Biological sulfate-reducing bacteria (SRB) may be effective in removing toxic lead and mercury ions (Pb(II) and Hg(II)) from wet flue gas desulfurization (FGD) wastewater through anaerobic sulfite reduction. To confirm this hypothesis, a sulfite-reducing up-flow anaerobic sludge blanket reactor was set up to treat FGD wastewater at metal loading rates of 9.2 g/m3-d Pb(II) and 2.6 g/m3-d Hg(II) for 50 days. The reactor removed 72.5 ± 7% of sulfite and greater than 99.5% of both Hg(II) and Pb(II). Most of the removed lead and mercury were deposited in the sludge as HgS and PbS. The contribution of cell adsorption and organic binding to Pb(II) and Hg(II) removal was 20.0 ± 0.1% and 1.8 ± 1.0%, respectively. The different bioavailable concentration levels of lead and mercury resulted in different levels of lethal toxicity. Cell viability analysis revealed that Hg(II) was less toxic than Pb(II) to the sludge microorganisms. In the batch tests, increasing the Hg(II) feeding concentration increased sulfite reduction rates. In conclusion, a sulfite-reducing reactor can efficiently remove sulfite, Pb(II) and Hg(II) from FGD wastewater. PMID:27455890

  1. Effects of Lead and Mercury on Sulfate-Reducing Bacterial Activity in a Biological Process for Flue Gas Desulfurization Wastewater Treatment.

    PubMed

    Zhang, Liang; Lin, Xiaojuan; Wang, Jinting; Jiang, Feng; Wei, Li; Chen, Guanghao; Hao, Xiaodi

    2016-01-01

    Biological sulfate-reducing bacteria (SRB) may be effective in removing toxic lead and mercury ions (Pb(II) and Hg(II)) from wet flue gas desulfurization (FGD) wastewater through anaerobic sulfite reduction. To confirm this hypothesis, a sulfite-reducing up-flow anaerobic sludge blanket reactor was set up to treat FGD wastewater at metal loading rates of 9.2 g/m(3)-d Pb(II) and 2.6 g/m(3)-d Hg(II) for 50 days. The reactor removed 72.5 ± 7% of sulfite and greater than 99.5% of both Hg(II) and Pb(II). Most of the removed lead and mercury were deposited in the sludge as HgS and PbS. The contribution of cell adsorption and organic binding to Pb(II) and Hg(II) removal was 20.0 ± 0.1% and 1.8 ± 1.0%, respectively. The different bioavailable concentration levels of lead and mercury resulted in different levels of lethal toxicity. Cell viability analysis revealed that Hg(II) was less toxic than Pb(II) to the sludge microorganisms. In the batch tests, increasing the Hg(II) feeding concentration increased sulfite reduction rates. In conclusion, a sulfite-reducing reactor can efficiently remove sulfite, Pb(II) and Hg(II) from FGD wastewater. PMID:27455890

  2. Analysis of Diversity and Activity of Sulfate-Reducing Bacterial Communities in Sulfidogenic Bioreactors Using 16S rRNA and dsrB Genes as Molecular Markers▿

    PubMed Central

    Dar, Shabir A.; Yao, Li; van Dongen, Udo; Kuenen, J. Gijs; Muyzer, Gerard

    2007-01-01

    Here we describe the diversity and activity of sulfate-reducing bacteria (SRB) in sulfidogenic bioreactors by using the simultaneous analysis of PCR products obtained from DNA and RNA of the 16S rRNA and dissimilatory sulfite reductase (dsrAB) genes. We subsequently analyzed the amplified gene fragments by using denaturing gradient gel electrophoresis (DGGE). We observed fewer bands in the RNA-based DGGE profiles than in the DNA-based profiles, indicating marked differences in the populations present and in those that were metabolically active at the time of sampling. Comparative sequence analyses of the bands obtained from rRNA and dsrB DGGE profiles were congruent, revealing the same SRB populations. Bioreactors that received either ethanol or isopropanol as an energy source showed the presence of SRB affiliated with Desulfobulbus rhabdoformis and/or Desulfovibrio sulfodismutans, as well as SRB related to the acetate-oxidizing Desulfobacca acetoxidans. The reactor that received wastewater containing a diverse mixture of organic compounds showed the presence of nutritionally versatile SRB affiliated with Desulfosarcina variabilis and another acetate-oxidizing SRB, affiliated with Desulfoarculus baarsii. In addition to DGGE analysis, we performed whole-cell hybridization with fluorescently labeled oligonucleotide probes to estimate the relative abundances of the dominant sulfate-reducing bacterial populations. Desulfobacca acetoxidans-like populations were most dominant (50 to 60%) relative to the total SRB communities, followed by Desulfovibrio-like populations (30 to 40%), and Desulfobulbus-like populations (15 to 20%). This study is the first to identify metabolically active SRB in sulfidogenic bioreactors by using the functional gene dsrAB as a molecular marker. The same approach can also be used to infer the ecological role of coexisting SRB in other habitats. PMID:17098925

  3. Electron microscopic characterization of the sulfate reducer Desulfovibrio vulgaris: biofilms and clumps

    NASA Astrophysics Data System (ADS)

    Auer, M.; Remis, J.; Jorgens, D.; Zemla, M.; Singer, M.; Schmitt, J.; Gorby, Y.; Hazen, T.; Wall, J.; Elias, D.; Torok, T.

    2008-12-01

    Numerous studies have helped characterize the stress response of the anaerobic sulfate reducer Desulfovibrio vulgaris Hildenborough (DvH). Yet all of these techniques represent bulk analyses of cells grown mostly under liquid culture conditions in large reactors. Such results represent an average over a large variety of individual cellular responses, hence assuming a homogeneous distribution of physiological traits. Moreover, only recently are those techniques applied to the environmentally more relevant condition of microbial communities (biofilms). What is missing is a detailed ultrastructural analysis of such biofilms in order to determine biofilm organization and its extracellular metal deposition distribution. Using sophisticated sample cryo-preparation approaches such as high-pressure freezing, freeze-substitution or microwave- assisted processing, followed serial section TEM imaging, we have found a large heterogeneity with respect to metal precipitation with some cells being surrounded by metal precipitates whereas neighboring cells, being genetically identical and seeing virtually the exact same microenvironment, completely lack extracellular metal deposits. Interestingly, apart from metal deposits near cell surfaces, we also found string- and sheet- like metal deposits in between neighboring cells that in mature biofilms can extend for hundreds of micrometers. In mature DvH biofilms such deposits were predominantly associated with areas of intact cells in biofilms, with areas devoid of such metal deposits displayed predominantly cell debris, suggesting a role of such deposits for cell survival, which may be of high significance to biofilms at DOE sites. Upon tomographic imaging we found that extracellular metal deposits were often associated with thin filaments and vesicle-like features. To complement our serial section 2D analysis of resin-embedded samples and the resulting limitation of sampling 3D biofilm as thin sections of arbitrary orientation, we

  4. Reactive Iron and Iron-Reducing Bacteria in Louisiana Continental Shelf Sediments

    EPA Science Inventory

    The Mississippi and Atchafalaya Rivers release sediments containing 15 x 106 t of iron onto the Louisiana continental shelf (LCS) each year. Iron oxides reaching the seafloor may be utilized as electron acceptors by iron-reducing bacteria for organic matter oxidation or become r...

  5. Methanogenesis and sulfate reduction: Competitive and noncompetitive substrates in estuarine sediments

    USGS Publications Warehouse

    Oremland, Ronald S.; Polcin, Sandra

    1982-01-01

    Sulfate ions did not inhibit methanogenesis in estuarine sediments supplemented with methanol, trimethylamine, or methionine. However, sulfate greatly retarded methanogenesis when hydrogen or acetate was the substrate. Sulfate reduction was stimulated by acetate, hydrogen, and acetate plus hydrogen, but not by methanol or trimethylamine. These results indicate that sulfate-reducing bacteria will outcompete methanogens for hydrogen, acetate, or both, but will not compete with methanogens for compounds like methanol, trimethylamine, or methionine, thereby allowing methanogenesis and sulfate reduction to operate simultaneously within anoxic, sulfate-containing sediments.

  6. Electric current generation by sulfur-reducing bacteria in microbial-anode fuel cell

    NASA Astrophysics Data System (ADS)

    Vasyliv, Oresta M.; Bilyy, Oleksandr I.; Ferensovych, Yaroslav P.; Hnatush, Svitlana O.

    2012-10-01

    Sulfur - reducing bacteria are a part of normal microflora of natural environment. Their main function is supporting of reductive stage of sulfur cycle by hydrogen sulfide production in the process of dissimilative sulfur-reduction. At the same time these bacteria completely oxidize organic compounds with CO2 and H2O formation. It was shown that they are able to generate electric current in the two chamber microbial-anode fuel cell (MAFC) by interaction between these two processes. Microbial-anode fuel cell on the basis of sulfur- and ferric iron-reducing Desulfuromonas acetoxidans bacteria has been constructed. It has been shown that the amount of electricity generation by investigated bacteria is influenced by the concentrations of carbon source (lactate) and ferric iron chloride. The maximal obtained electric current and potential difference between electrodes equaled respectively 0.28-0.29 mA and 0.19-0.2 V per 0.3 l of bacterial suspension with 0.4 g/l of initial biomass that was grown under the influence of 0.45 mM of FeCl3 and 3 g/l of sodium lactate as primal carbon source. It has also been shown that these bacteria are resistant to different concentrations of silver ions.

  7. Genus-specific and phase-dependent effects of nitrate on a sulfate-reducing bacterial community as revealed by dsrB-based DGGE analyses of wastewater reactors.

    PubMed

    Mizuno, Kouhei; Morishita, Yui; Ando, Akiko; Tsuchiya, Naofumi; Hirata, Mai; Tanaka, Kenji

    2012-02-01

    The biogenic production of hydrogen sulfide is a serious problem associated with wastewater treatment. The aim of this study was to investigate the inhibitory effect of nitrate on the dynamics of sulfate-reducing bacteria (SRB) community in a laboratory-scale wastewater reactor, originating from a denitrifying plant using activated sludge. For this purpose, denaturing gradient gel electrophoresis (DGGE) analysis targeting the dsrB (dissimilatory sulfite reductase) gene was used in combination with chemical analyses and measurement of oxidation and reduction potential (ORP). The reactors were initially dosed with 1.0 and 4.0 g/L potassium nitrate and anaerobically incubated for 490 h. Addition of 4.0 g/L nitrate to the reactor was associated with a prolonged inhibition (over 300 h, i.e., 12.5 days) of sulfate reduction and this was consistent with a rapid decrease in ORP associated with nitrate depletion. The DGGE analysis revealed that nitrate addition remarkably attenuated a distinct group of dsrB related to Desulfovibrio, whereas other dsrB groups were not influenced. Furthermore, another sulfate reduction by Syntrophobacter in the later stages of the incubation period occurred in both reactors (regardless of the nitrate concentration), suggesting that different SRB groups are associated with sulfate reduction at different stages of the wastewater treatment process. PMID:22806863

  8. Anaerobic degradation of toluene and xylene by aquifer microorganisms under sulfate-reducing conditions.

    PubMed Central

    Edwards, E A; Wills, L E; Reinhard, M; Grbić-Galić, D

    1992-01-01

    Toluene and the three isomers of xylene were completely mineralized to CO2 and biomass by aquifer-derived microorganisms under strictly anaerobic conditions. The source of the inoculum was gasoline-contaminated sediment from Seal Beach, Calif. Evidence confirming that sulfate was the terminal electron acceptor is presented. Benzene and ethylbenzene were not degraded under the experimental conditions used. Successive transfers of the mixed cultures that were enriched from aquifer sediments retained the ability to degrade toluene and xylenes. Greater than 90% of 14C-labeled toluene or 14C-labeled o-xylene was mineralized to 14CO2. The doubling time for the culture grown on toluene or m-xylene was about 20 days, and the cell yield was about 0.1 to 0.14 g of cells (dry weight) per g of substrate. The accumulation of sulfide in the cultures as a result of sulfate reduction appeared to inhibit degradation of aromatic hydrocarbons. PMID:1575482

  9. TEM investigation of U{sup 6+} and Re{sup 7+} reduction by Desulfovibrio desulfuricans, a sulfate-reducing bacterium

    SciTech Connect

    XU,HUIFANG; BARTON,LARRY L.; CHOUDHURY,KEKA; ZHANG,PENGCHU; WANG,YIFENG

    2000-03-14

    Uranium and its fission product Tc in aerobic environment will be in the forms of UO{sub 2}{sup 2+} and TcO{sub 4}{sup {minus}}. Reduced forms of tetravalent U and Tc are sparingly soluble. As determined by transmission electron microscopy, the reduction of uranyl acetate by immobilized cells of Desulfovibrio desulfuricans results in the production of black uraninite nanocrystals precipitated outside the cell. Some nanocrystals are associated with outer membranes of the cell as revealed from cross sections of these metabolic active sulfate-reducing bacteria. The nanocrystals have an average diameter of 5 nm and have anhedral shape. The reduction of Re{sup 7+} by cells of Desulfovibrio desulfuricans is fast in media containing H{sub 2} an electron donor, and slow in media containing lactic acid. It is proposed that the cytochrome in these cells has an important role in the reduction of uranyl and Re{sup 7+} is (a chemical analogue for Tc{sup 7+}) through transferring an electron from molecular hydrogen or lactic acid to the oxyions of UO{sub 2}{sup 2+} and TcO{sub 4}{sup {minus}}.

  10. Inhibitory bacteria reduce fungi on early life stages of endangered Colorado boreal toads (Anaxyrus boreas).

    PubMed

    Kueneman, Jordan G; Woodhams, Douglas C; Van Treuren, Will; Archer, Holly M; Knight, Rob; McKenzie, Valerie J

    2016-04-01

    Increasingly, host-associated microbiota are recognized to mediate pathogen establishment, providing new ecological perspectives on health and disease. Amphibian skin-associated microbiota interact with the fungal pathogen, Batrachochytrium dendrobatidis (Bd), but little is known about microbial turnover during host development and associations with host immune function. We surveyed skin microbiota of Colorado's endangered boreal toads (Anaxyrus boreas), sampling 181 toads across four life stages (tadpoles, metamorphs, subadults and adults). Our goals were to (1) understand variation in microbial community structure among individuals and sites, (2) characterize shifts in communities during development and (3) examine the prevalence and abundance of known Bd-inhibitory bacteria. We used high-throughput 16S and 18S rRNA gene sequencing (Illumina MiSeq) to characterize bacteria and microeukaryotes, respectively. Life stage had the largest effect on the toad skin microbial community, and site and Bd presence also contributed. Proteobacteria dominated tadpole microbial communities, but were later replaced by Actinobacteria. Microeukaryotes on tadpoles were dominated by the classes Alveolata and Stramenopiles, while fungal groups replaced these groups after metamorphosis. Using a novel database of Bd-inhibitory bacteria, we found fewer Bd-inhibitory bacteria in post-metamorphic stages correlated with increased skin fungi, suggesting that bacteria have a strong role in early developmental stages and reduce skin-associated fungi. PMID:26565725

  11. Desulfosoma caldarium gen. nov., sp. nov., a thermophilic sulfate-reducing bacterium from a terrestrial hot spring.

    PubMed

    Baena, Sandra; Perdomo, Natalia; Carvajal, Catalina; Díaz, Carolina; Patel, Bharat K C

    2011-04-01

    A thermophilic, sulfate-reducing bacterium, designated strain USBA-053(T), was isolated from a terrestrial hot spring located at a height of 2500 m in the Colombian Andes (5° 45' 33.29″ N 73° 6' 49.89″ W), Colombia. Cells of strain USBA-053(T) were oval- to rod-shaped, Gram-negative and motile by means of a single polar flagellum. The strain grew autotrophically with H(2) as the electron donor and heterotrophically on formate, propionate, butyrate, valerate, isovalerate, lactate, pyruvate, ethanol, glycerol, serine and hexadecanoic acid in the presence of sulfate as the terminal electron acceptor. The main end products from lactate degradation, in the presence of sulfate, were acetate, CO(2) and H(2)S. Strain USBA-053(T) fermented pyruvate in the absence of sulfate and grew optimally at 57 °C (growth temperature ranged from 50 °C to 62 °C) and pH 6.8 (growth pH ranged from 5.7 to 7.7). The novel strain was slightly halophilic and grew in NaCl concentrations ranging from 5 to 30 g l(-1), with an optimum at 25 g l(-1) NaCl. Sulfate, thiosulfate and sulfite were used as electron acceptors, but not elemental sulfur, nitrate or nitrite. The G+C content of the genomic DNA was 56±1 mol%. 16S rRNA gene sequence analysis indicated that strain USBA-053(T) was a member of the class Deltaproteobacteria, with Desulfacinum hydrothermale MT-96(T) as the closest relative (93 % gene sequence similarity). On the basis of physiological characteristics and phylogenetic analysis, it is suggested that strain USBA-053(T) represents a new genus and novel species for which the name Desulfosoma caldarium gen. nov., sp. nov. is proposed. The type strain of the type species is USBA-053(T) ( = KCTC 5670(T) = DSM 22027(T)). PMID:20418410

  12. SO 2 adsorption and thermal stability and reducibility of sulfates formed on the magnesium-aluminate spinel sulfur-transfer catalyst

    NASA Astrophysics Data System (ADS)

    Wang, Jin-an; Li, Cheng-lie

    2000-07-01

    Magnesium-aluminate spinel used as a sulfur-transfer catalyst in the fluid catalytic cracking units for SO x emission control was prepared by the precipitation method. The crystalline structure, textural property, and surface dehydroxylation of the sample were characterized by thermogravimetry-derivative thermogravimetry (TG-DTG), differential thermal analysis (DTA), X-ray diffraction (XRD), liquid N 2 adsorption-desorption and infrared spectroscopy (IR) measurements. The behavior of SO 2 adsorption and oxidation on the surface of catalyst was evaluated with IR from 50°C to 600°C. Particularly, the thermal stability and H 2-reducibility of the formed sulfite or sulfate during SO 2 adsorption or oxidation were tested under various conditions. In the absence of oxygen in the feed mixture, weak physically adsorbed SO 2 species and surface sulfite were identified. In the case of SO 2 oxidative adsorption, both surface sulfate and bulk-like sulfate were formed. When the sulfated sample was reduced with hydrogen, the surface sulfite and sulfates were completely removed below 550°C in vacuum. The bulk-like sulfate, however, showed a high ability to resist H 2-reduction, which indicates that the reducibility of bulk-like sulfate formed on magnesium-aluminate spinel must be enhanced when it is used as a sulfur-transfer catalyst.

  13. Anaerobic degradation of p-Xylene by a sulfate-reducing enrichment culture.

    PubMed

    Morasch, Barbara; Meckenstock, Rainer U

    2005-08-01

    A strictly anaerobic enrichment culture was obtained with p-xylene as organic substrate and sulfate as electron acceptor from an aquifer at a former gasworks plant contaminated with aromatic hydrocarbons. p-Xylene was completely oxidized to CO(2). The enrichment culture depended on Fe(II) in the medium as a scavenger of the produced sulfide. 4-Methylbenzylsuccinic acid and 4-methylphenylitaconic acid were identified in supernatants of cultures indicating that degradation of p-xylene was initiated by fumarate addition to one of the methyl groups. Therefore, p-xylene degradation probably proceeds analogously to toluene degradation by Thauera aromatica or anaerobic degradation pathways for o- and m-xylene. PMID:16049661

  14. Low-Molecular-Weight Sulfonates, a Major Substrate for Sulfate Reducers in Marine Microbial Mats†

    PubMed Central

    Visscher, Pieter T.; Gritzer, Rachel F.; Leadbetter, Edward R.

    1999-01-01

    Several low-molecular-weight sulfonates were added to microbial mat slurries to investigate their effects on sulfate reduction. Instantaneous production of sulfide occurred after taurine and cysteate were added to all of the microbial mats tested. The rates of production in the presence of taurine and cysteate were 35 and 24 μM HS− h−1 in a stromatolite mat, 38 and 36 μM HS− h−1 in a salt pond mat, and 27 and 18 μM HS− h−1 in a salt marsh mat, respectively. The traditionally used substrates lactate and acetate stimulated the rate of sulfide production 3 to 10 times more than taurine and cysteate stimulated the rate of sulfide production in all mats, but when ethanol, glycolate, and glutamate were added to stromatolite mat slurries, the resulting increases were similar to the increases observed with taurine and cysteate. Isethionate, sulfosuccinate, and sulfobenzoate were tested only with the stromatolite mat slurry, and these compounds had much smaller effects on sulfide production. Addition of molybdate resulted in a greater inhibitory effect on acetate and lactate utilization than on sulfonate use, suggesting that different metabolic pathways were involved. In all of the mats tested taurine and cysteate were present in the pore water at nanomolar to micromolar concentrations. An enrichment culture from the stromatolite mat was obtained on cysteate in a medium lacking sulfate and incubated anaerobically. The rate of cysteate consumption by this enrichment culture was 1.6 pmol cell−1 h−1. Compared to the results of slurry studies, this rate suggests that organisms with properties similar to the properties of this enrichment culture are a major constituent of the sulfidogenic population. In addition, taurine was consumed at some of highest dilutions obtained from most-probable-number enrichment cultures obtained from stromatolite samples. Based on our comparison of the sulfide production rates found in various mats, low-molecular-weight sulfonates

  15. Potential Activity, Size, and Structure of Sulfate-Reducing Microbial Communities in an Exposed, Grazed and a Sheltered, Non-Grazed Mangrove Stand at the Red Sea Coast

    PubMed Central

    Balk, Melike; Keuskamp, Joost A.; Laanbroek, Hendrikus J.

    2015-01-01

    After oxygen, sulfate is the most important oxidant for the oxidation of organic matter in mangrove forest soils. As sulfate reducers are poor competitors for common electron donors, their relative success depends mostly on the surplus of carbon that is left by aerobic organisms due to oxygen depletion. We therefore hypothesized that sulfate-cycling in mangrove soils is influenced by the size of net primary production, and hence negatively affected by mangrove degradation and exploitation, as well as by carbon-exporting waves. To test this, we compared quantitative and qualitative traits of sulfate-reducing communities in two Saudi-Arabian mangrove stands near Jeddah, where co-occurring differences in camel-grazing pressure and tidal exposure led to a markedly different stand height and hence primary production. Potential sulfate reduction rates measured in anoxic flow-through reactors in the absence and presence of additional carbon sources were significantly higher in the samples from the non-grazed site. Near the surface (0–2 cm depth), numbers of dsrB gene copies and culturable cells also tended to be higher in the non-grazed sites, while these differences were not detected in the sub-surface (4–6 cm depth). It was concluded that sulfate-reducing microbes at the surface were indeed repressed at the low-productive site as could be expected from our hypothesis. At both sites, sulfate reduction rates as well as numbers of the dsrB gene copies and viable cells increased with depth suggesting repression of sulfate reduction near the surface in both irrespective of production level. Additionally, sequence analysis of DNA bands obtained from DGGE gels based on the dsrB gene, showed a clear difference in dominance of sulfate-reducing genera belonging to the Deltaproteobacteria and the Firmicutes between sampling sites and depths. PMID:26733999

  16. Potential Activity, Size, and Structure of Sulfate-Reducing Microbial Communities in an Exposed, Grazed and a Sheltered, Non-Grazed Mangrove Stand at the Red Sea Coast.

    PubMed

    Balk, Melike; Keuskamp, Joost A; Laanbroek, Hendrikus J

    2015-01-01

    After oxygen, sulfate is the most important oxidant for the oxidation of organic matter in mangrove forest soils. As sulfate reducers are poor competitors for common electron donors, their relative success depends mostly on the surplus of carbon that is left by aerobic organisms due to oxygen depletion. We therefore hypothesized that sulfate-cycling in mangrove soils is influenced by the size of net primary production, and hence negatively affected by mangrove degradation and exploitation, as well as by carbon-exporting waves. To test this, we compared quantitative and qualitative traits of sulfate-reducing communities in two Saudi-Arabian mangrove stands near Jeddah, where co-occurring differences in camel-grazing pressure and tidal exposure led to a markedly different stand height and hence primary production. Potential sulfate reduction rates measured in anoxic flow-through reactors in the absence and presence of additional carbon sources were significantly higher in the samples from the non-grazed site. Near the surface (0-2 cm depth), numbers of dsrB gene copies and culturable cells also tended to be higher in the non-grazed sites, while these differences were not detected in the sub-surface (4-6 cm depth). It was concluded that sulfate-reducing microbes at the surface were indeed repressed at the low-productive site as could be expected from our hypothesis. At both sites, sulfate reduction rates as well as numbers of the dsrB gene copies and viable cells increased with depth suggesting repression of sulfate reduction near the surface in both irrespective of production level. Additionally, sequence analysis of DNA bands obtained from DGGE gels based on the dsrB gene, showed a clear difference in dominance of sulfate-reducing genera belonging to the Deltaproteobacteria and the Firmicutes between sampling sites and depths. PMID:26733999

  17. Synthesis of bacteria promoted reduced graphene oxide-nickel sulfide networks for advanced supercapacitors.

    PubMed

    Zhang, Haiming; Yu, Xinzhi; Guo, Di; Qu, Baihua; Zhang, Ming; Li, Qiuhong; Wang, Taihong

    2013-08-14

    Supercapacitors with potential high power are useful and have attracted much attention recently. Graphene-based composites have been demonstrated to be promising electrode materials for supercapacitors with enhanced properties. To improve the performance of graphene-based composites further and realize their synthesis with large scale, we report a green approach to synthesize bacteria-reduced graphene oxide-nickel sulfide (BGNS) networks. By using Bacillus subtilis as spacers, we deposited reduced graphene oxide/Ni3S2 nanoparticle composites with submillimeter pores directly onto substrate by a binder-free electrostatic spray approach to form BGNS networks. Their electrochemical capacitor performance was evaluated. Compared with stacked reduced graphene oxide-nickel sulfide (GNS) prepared without the aid of bacteria, BGNS with unique nm-μm structure exhibited a higher specific capacitance of about 1424 F g(-1) at a current density of 0.75 A g(-1). About 67.5% of the capacitance was retained as the current density increased from 0.75 to 15 A g(-1). At a current density of 75 A g(-1), a specific capacitance of 406 F g(-1) could still remain. The results indicate that the reduced graphene oxide-nickel sulfide network promoted by bacteria is a promising electrode material for supercapacitors. PMID:23751359

  18. Mineral transformations during the dissolution of uranium ore minerals by dissimilatory metal-reducing bacteria

    NASA Astrophysics Data System (ADS)

    Glasauer, S.; Weidler, P.; Fakra, S.; Tyliszczak, T.; Shuh, D.

    2011-12-01

    Carnotite minerals [X2(UO2)2(VO4)2]; X = K, Ca, Ba, Mn, Na, Cu or Pb] form the major ore of uranium in the Colorado Plateau. These deposits are highly oxidized and contain U(VI) and V(IV). The biotransformation of U(VI) bound in carnotite by bacteria during dissimilatory metal reduction presents a complex puzzle in mineral chemistry. Both U(VI) and V(V) can be respired by metal reducing bacteria, and the mineral structure can change depending on the associated counterion. We incubated anaerobic cultures of S. putrefaciens CN32 with natural carnotite minerals from southeastern Utah in a nutrient-limited defined medium. Strain CN32 is a gram negative bacterium and a terrestrial isolate from New Mexico. The mineral and metal transformations were compared to a system that contained similar concentrations of soluble U(VI) and V(V). Electron (SEM, TEM) microscopies and x-ray spectromicroscopy (STXM) were used in conjunction with XRD to track mineral changes, and bacterial survival was monitored throughout the incubations. Slow rates of metal reduction over 10 months for the treatment with carnotite minerals revealed distinct biotic and abiotic processes, providing insight on mineral transformation and bacteria-metal interactions. The bacteria existed as small flocs or individual cells attached to the mineral phase, but did not adsorb soluble U or V, and accumulated very little of the biominerals. Reduction of mineral V(V) necessarily led to a dismantling of the carnotite structure. Bioreduction of V(V) by CN32 contributed small but profound changes to the mineral system, resulting in new minerals. Abiotic cation exchange within the carnotite group minerals induced the rearrangement of the mineral structures, leading to further mineral transformation. In contrast, bacteria survival was poor for treatments with soluble U(VI) and V(V), although both metals were reduced completely and formed solid UO2 and VO2; we also detected V(III). For these treatments, the bacteria

  19. Iron catalyzed reduction of chromate by dissimilatory iron-reducing bacteria.

    SciTech Connect

    Wielinga, B.W.; M.M. Mizuba; C.M. Hansel; S. Fendorf

    2001-02-01

    The toxicity and mobility of chromium can be diminished through its reduction from the hexavalent state to the trivalent form. Here we demonstrate a microbially mediated pathway for chromate reduction. Iron reducing bacteria, ubiquitous organisms within soils and sediments, stimulate chromate reduction by generating ferrous iron--a facile reductant of hexavalent chromium. Subsequent to reduction, Cr(III) then precipitates as a chromium hydroxide.

  20. Extracellular Electron Transfer Is a Bottleneck in the Microbiologically Influenced Corrosion of C1018 Carbon Steel by the Biofilm of Sulfate-Reducing Bacterium Desulfovibrio vulgaris.

    PubMed

    Li, Huabing; Xu, Dake; Li, Yingchao; Feng, Hao; Liu, Zhiyong; Li, Xiaogang; Gu, Tingyue; Yang, Ke

    2015-01-01

    Carbon steels are widely used in the oil and gas industry from downhole tubing to transport trunk lines. Microbes form biofilms, some of which cause the so-called microbiologically influenced corrosion (MIC) of carbon steels. MIC by sulfate reducing bacteria (SRB) is often a leading cause in MIC failures. Electrogenic SRB sessile cells harvest extracellular electrons from elemental iron oxidation for energy production in their metabolism. A previous study suggested that electron mediators riboflavin and flavin adenine dinucleotide (FAD) both accelerated the MIC of 304 stainless steel by the Desulfovibrio vulgaris biofilm that is a corrosive SRB biofilm. Compared with stainless steels, carbon steels are usually far more prone to SRB attacks because SRB biofilms form much denser biofilms on carbon steel surfaces with a sessile cell density that is two orders of magnitude higher. In this work, C1018 carbon steel coupons were used in tests of MIC by D. vulgaris with and without an electron mediator. Experimental weight loss and pit depth data conclusively confirmed that both riboflavin and FAD were able to accelerate D. vulgaris attack against the carbon steel considerably. It has important implications in MIC failure analysis and MIC mitigation in the oil and gas industry. PMID:26308855

  1. Extracellular Electron Transfer Is a Bottleneck in the Microbiologically Influenced Corrosion of C1018 Carbon Steel by the Biofilm of Sulfate-Reducing Bacterium Desulfovibrio vulgaris

    PubMed Central

    Li, Yingchao; Feng, Hao; Liu, Zhiyong; Li, Xiaogang; Gu, Tingyue; Yang, Ke

    2015-01-01

    Carbon steels are widely used in the oil and gas industry from downhole tubing to transport trunk lines. Microbes form biofilms, some of which cause the so-called microbiologically influenced corrosion (MIC) of carbon steels. MIC by sulfate reducing bacteria (SRB) is often a leading cause in MIC failures. Electrogenic SRB sessile cells harvest extracellular electrons from elemental iron oxidation for energy production in their metabolism. A previous study suggested that electron mediators riboflavin and flavin adenine dinucleotide (FAD) both accelerated the MIC of 304 stainless steel by the Desulfovibrio vulgaris biofilm that is a corrosive SRB biofilm. Compared with stainless steels, carbon steels are usually far more prone to SRB attacks because SRB biofilms form much denser biofilms on carbon steel surfaces with a sessile cell density that is two orders of magnitude higher. In this work, C1018 carbon steel coupons were used in tests of MIC by D. vulgaris with and without an electron mediator. Experimental weight loss and pit depth data conclusively confirmed that both riboflavin and FAD were able to accelerate D. vulgaris attack against the carbon steel considerably. It has important implications in MIC failure analysis and MIC mitigation in the oil and gas industry. PMID:26308855

  2. Removal of copper in an integrated sulfate reducing bioreactor-crystallization reactor system.

    PubMed

    Sierra-Alvarez, Reyes; Hollingsworth, Jeremy; Zhou, Michael S

    2007-02-15

    Removal of copper was investigated using an innovative water treatment system integrating a sulfidogenic bioreactor with a fluidized-bed crystallization reactor containing fine sand to facilitate the recovery of copper as a purified copper-sulfide mineral. The performance of the system was tested using a simulated semiconductor manufacturing wastewater containing high levels of Cu2+ (4-66 mg/L), sulfate, and a mixture of citrate, isopropanol, and polyethylene glycol (Mn 300). Soluble copper removal efficiencies exceeding 99% and effluent copper concentrations averaging 89 micog/L were demonstrated in the two-stage system, with near complete metal removal occurring in the crystallizer. Copper crystals deposited on sand grains were identified as covellite (CuS). The removal of organic constituents did not exceed 70% of the initial chemical oxygen demand due to incomplete degradation of isopropanol and its breakdown product (acetone). Taken as a whole, these results indicate the potential of this novel reactor configuration for the simultaneous removal of heavy metals and organic constituents. The ability of this process to recover heavy metals in a purified form makes it particularly attractive for the treatment of contaminated aqueous streams, including industrial wastewaters and acid mine drainage. PMID:17593752

  3. Isolation, identification and characterization of highly tellurite-resistant, tellurite-reducing bacteria from Antarctica

    NASA Astrophysics Data System (ADS)

    Arenas, Felipe A.; Pugin, Benoit; Henríquez, Nicole A.; Arenas-Salinas, Mauricio A.; Díaz-Vásquez, Waldo A.; Pozo, María F.; Muñoz, Claudia M.; Chasteen, Thomas G.; Pérez-Donoso, José M.; Vásquez, Claudio C.

    2014-03-01

    The tellurium oxyanion, tellurite, is extremely noxious to most living organisms. Its toxicity has been mainly related to the generation of reactive oxygen species (ROS) as well as to an unbalancing of the thiol:redox buffering system. Nevertheless, a few bacteria are capable of thriving at high tellurite concentrations. One mechanism of resistance is the enzymatic and non-enzymatic reduction of tellurite to the less toxic elemental tellurium. This reduction generates nano- to micrometric tellurium crystals that display different shapes and sizes. To date, a very limited number of highly tellurite-resistant and tellurite-reducing bacterial species are available from international culture collections. In this work, we decided to look for tellurite-reducing bacteria from an extreme environment, Antarctica. This environment exhibits a combination of several extreme factors such as high UV-radiation and desiccation and freezing conditions that impact directly on the local biodiversity. Since, as does, all these factors induce ROS formation, we hypothesized that Antarctic bacteria could also exhibit tellurite-resistance. In this context, we isolated 123 tellurite-resistant bacteria, and characterized six new tellurite-resistant and tellurite-reducing bacterial strains from samples collected in Antarctica. These strains were identified according to their 16S rRNA gene sequence as Staphylococcus hameolyticus, Staphylococcus sciuri, Acinetobacter haemolyticus, Pseudomonas lini, and two strains of Psychrobacter immobilis. The isolates display tellurite-resistance about 35- to 500-fold higher than Escherichia coli (Te-sensitive organism), and a high level of tellurite reduction which might be interesting for an application in the field of bioremediation or nanoparticle biosynthesis.

  4. [Characterization of Cr (VI) removal and total Cr equilibrium adsorption by sulfate reducing granular sludge in stimulant wastewater].

    PubMed

    Luo, Jun; Pang, Zhi-Hua; Hu, Yong-You; Zhong, Hai-Tao; Chen, Jian-Yu; Lin, Fang-Min

    2010-11-01

    Sulfate reducing granular sludge (SRGS) cultivated in small scale EGSB reactor was used for Cr (VI) removing. Characterization of Cr (VI) removal and total Cr equilibrium adsorption was studied, and the adsorption isotherm was fitted. Results showed that removal of Cr (VI) was in connection with the structure and chemical composition of SRGS and several environmental factors. The Cr (VI) removal rate increased with the dosage of granular sludge; the increasing of oscillation speed and temperature could enhance Cr (VI) removal and total Cr adsorption, but while the oscillation speed reached 150 r x min(-1) or the temperature came to 40 degrees C, the physical structure of granular sludge would be affected and the granular sludge discrete, and total Cr equilibrium adsorption decreased; lower pH value caused higher Cr (VI) removal rate, however the sulfate on the surface of granular sludge was affected by lower pH value easily and would translate into H2S, then total Cr adsorption rate decreased. Cr (VI) removal would be influenced by physical, chemical and biological factors, and the process included reduction and adsorption mainly. The maximum adsorption of total Cr by granular sludge was 6.84 mg x g(-1), and the total Cr adsorbing process fitted in with Langmuir adsorption isotherm. PMID:21250453

  5. Thermodesulfobacterium geofontis sp. nov., a hyperthermophilic, sulfate-reducing bacterium isolated from Obsidian Pool, Yellowstone National Park.

    PubMed

    Hamilton-Brehm, Scott D; Gibson, Robert A; Green, Stefan J; Hopmans, Ellen C; Schouten, Stefan; van der Meer, Marcel T J; Shields, John P; Damsté, Jaap S S; Elkins, James G

    2013-03-01

    A novel sulfate-reducing bacterium designated OPF15(T) was isolated from Obsidian Pool, Yellowstone National Park, Wyoming. The phylogeny of 16S rRNA and functional genes (dsrAB) placed the organism within the family Thermodesulfobacteriaceae. The organism displayed hyperthermophilic temperature requirements for growth with a range of 70-90 °C and an optimum of 83 °C. Optimal pH was around 6.5-7.0 and the organism required the presence of H2 or formate as an electron donor and CO2 as a carbon source. Electron acceptors supporting growth included sulfate, thiosulfate, and elemental sulfur. Lactate, acetate, pyruvate, benzoate, oleic acid, and ethanol did not serve as electron donors. Membrane lipid analysis revealed diacyl glycerols and acyl/ether glycerols which ranged from C14:0 to C20:0. Alkyl chains present in acyl/ether and diether glycerol lipids ranged from C16:0 to C18:0. Straight, iso- and anteiso-configurations were found for all lipid types. The presence of OPF15(T) was also shown to increase cellulose consumption during co-cultivation with Caldicellulosiruptor obsidiansis, a fermentative, cellulolytic extreme thermophile isolated from the same environment. On the basis of phylogenetic, phenotypic, and structural analyses, Thermodesulfobacterium geofontis sp. nov. is proposed as a new species with OPF15(T) representing the type strain. PMID:23345010

  6. Thermodesulfobacterium geofontis sp. nov., a hyperthermophilic, sulfate-reducing bacterium isolated from Obsidian Pool, Yellowstone National Park

    SciTech Connect

    Hamilton-Brehm, Scott D.; Gibson, Robert A.; Green, Stefan J.; Hopmans, Ellen C.; Schouten, Stefan; van der Meer, Marcel T. J.; Shields, John P.; Damsté, Jaap S. S.; Elkins, James G.

    2013-01-24

    A novel sulfate-reducing bacterium designated OPF15T was isolated from Obsidian Pool, Yellowstone National Park, Wyoming. The phylogeny of 16S rRNA and functional genes (dsrAB) placed the organism within the family Thermodesulfobacteriaceae. The organism displayed hyperthermophilic temperature requirements for growth with a range of 70 90 C and an optimum of 83 C. Optimal pH was around 6.5 7.0 and the organism required the presence of H2 or formate as an electron donor and CO2 as a carbon source. Electron acceptors supporting growth included sulfate, thiosulfate, and elemental sulfur. Lactate, acetate, pyruvate, benzoate, oleic acid, and ethanol did not serve as electron donors. Membrane lipid analysis revealed diacyl glycerols and acyl/ether glycerols which ranged from C14:0 to C20:0. Alkyl chains present in acyl/ether and diether glycerol lipids ranged from C16:0 to C18:0. Straight, iso- and anteiso-configurations were found for all lipid types. The presence of OPF15T was also shown to increase cellulose consumption during co-cultivation with Caldicellulosiruptor obsidiansis, a fermentative, cellulolytic extreme thermophile isolated from the same environment. On the basis of phylogenetic, phenotypic, and structural analyses, Thermodesulfobacterium geofontis sp. nov. is proposed as a new species with OPF15T representing the type strain.

  7. Desulfonatronum paiuteum sp. nov.: A New Alkaliphilic, Sulfate-Reducing Bacterium, Isolated from Soda Mono Lake, California

    NASA Technical Reports Server (NTRS)

    Pikuta, Elena; Hoover, Richard B.; Marsic, Damien; Whitman, William; Cleland, David; Krader, Paul; Six, N. Frank (Technical Monitor)

    2002-01-01

    A novel alkaliphilic, sulfate reducing bacterium strain MLF1(sup T) was isolated from sediments of soda Mono Lake, California. Gram-negative vibrion cells, motile by singular polar flagellum, with sizes 0.5 - 0.6x 1.2 - 2.0 micron occurred singly, in pairs or short spirilla. Growth was observed over the temperature range of +15 C to +48 C (optimum +37 C), NaCl concentration range is greater than 1 - 7 %, wt/vol (optimum 3 %, wt/vol) and pH range 7.8 - 10.5 (optimum pH 9.0 - 9.4). The novel isolate is strictly alkaliphilic, requires high carbonate concentration in medium, obligately anaerobic and catalase negative. As electron donors strain MLF1(sup T) uses hydrogen, formate, ethanol. Sulfate, sulfite, and thiosulfate (but not sulfur or nitrate) can be used as electron acceptors. The sole end product of growth on formate was H2S. Strain MLF1(sup T) is resistant to kanamycin and gentamycin, but sensitive to chloramphenicol and tetracycline. Na2MoO4 inhibits growth of strain MLF1(sup T). The sum of G+C in DNA is 63.1 mol% (by HPLC method). On the basis of physiological and molecular properties, the isolate was considered as novel species of genus Desulfonatronum; and the name Desulfonatronum paiuteum sp. nov., is proposed (type strain MLF1(sup T) = ATCC BAA-395(sup T) = DSMZ 14708(sup T).

  8. Degradation of o-xylene and m-xylene by a novel sulfate-reducer belonging to the genus Desulfotomaculum.

    PubMed

    Morasch, Barbara; Schink, Bernhard; Tebbe, Christoph C; Meckenstock, Rainer U

    2004-06-01

    A strictly anaerobic bacterium, strain OX39, was isolated with o-xylene as organic substrate and sulfate as electron acceptor from an aquifer at a former gasworks plant contaminated with aromatic hydrocarbons. Apart from o-xylene, strain OX39 grew on m-xylene and toluene and all three substrates were oxidized completely to CO(2). Induction experiments indicated that o-xylene, m-xylene, and toluene degradation were initiated by different specific enzymes. Methylbenzylsuccinate was identified in supernatants of cultures grown on o-xylene and m-xylene, and benzylsuccinate was detected in supernatants of toluene-grown cells, thus indicating that degradation was initiated in all three cases by fumarate addition to the methyl group. Strain OX39 was sensitive towards sulfide and depended on Fe(II) in the medium as a scavenger of the produced sulfide. Analysis of the PCR-amplified 16S rRNA gene revealed that strain OX39 affiliates with the gram-positive endospore-forming sulfate reducers of the genus Desulfotomaculum and is the first hydrocarbon-oxidizing bacterium in this genus. PMID:15127183

  9. Anaerobic oxidation of long-chain n-alkanes by the hyperthermophilic sulfate-reducing archaeon, Archaeoglobus fulgidus

    PubMed Central

    Khelifi, Nadia; Amin Ali, Oulfat; Roche, Philippe; Grossi, Vincent; Brochier-Armanet, Céline; Valette, Odile; Ollivier, Bernard; Dolla, Alain; Hirschler-Réa, Agnès

    2014-01-01

    The thermophilic sulfate-reducing archaeon Archaeoglobus fulgidus strain VC-16 (DSM 4304), which is known to oxidize fatty acids and n-alkenes, was shown to oxidize saturated hydrocarbons (n-alkanes in the range C10–C21) with thiosulfate or sulfate as a terminal electron acceptor. The amount of n-hexadecane degradation observed was in stoichiometric agreement with the theoretically expected amount of thiosulfate reduction. One of the pathways used by anaerobic microorganisms to activate alkanes is addition to fumarate that involves alkylsuccinate synthase as a key enzyme. A search for genes encoding homologous enzymes in A. fulgidus identified the pflD gene (locus-tag AF1449) that was previously annotated as a pyruvate formate lyase. A phylogenetic analysis revealed that this gene is of bacterial origin and was likely acquired by A. fulgidus from a bacterial donor through a horizontal gene transfer. Based on three-dimensional modeling of the corresponding protein and molecular dynamic simulations, we hypothesize an alkylsuccinate synthase activity for this gene product. The pflD gene expression was upregulated during the growth of A. fulgidus on an n-alkane (C16) compared with growth on a fatty acid. Our results suggest that anaerobic alkane degradation in A. fulgidus may involve the gene pflD in alkane activation through addition to fumarate. These findings highlight the possible importance of hydrocarbon oxidation at high temperatures by A. fulgidus in hydrothermal vents and the deep biosphere. PMID:24763368

  10. Effects of intestinal bacteria-derived p-cresyl sulfate on Th1-type immune response in vivo and in vitro.

    PubMed

    Shiba, Takahiro; Kawakami, Koji; Sasaki, Takashi; Makino, Ikuyo; Kato, Ikuo; Kobayashi, Toshihide; Uchida, Kazumi; Kaneko, Kimiyuki

    2014-01-15

    Protein fermentation by intestinal bacteria generates various compounds that are not synthesized by their hosts. An example is p-cresol, which is produced from tyrosine. Patients with chronic kidney disease (CKD) accumulate high concentrations of intestinal bacteria-derived p-cresyl sulfate (pCS), which is the major metabolite of p-cresol, in their blood, and this accumulation contributes to certain CKD-associated disorders. Immune dysfunction is a CKD-associated disorder that frequently contributes to infectious diseases among CKD patients. Although some studies imply pCS as an etiological factor, the relation between pCS and immune systems is poorly understood. In the present study, we investigated the immunological effects of pCS derived from intestinal bacteria in mice. For this purpose, we fed mice a tyrosine-rich diet that causes the accumulation of pCS in their blood. The mice were shown to exhibit decreased Th1-driven 2, 4-dinitrofluorobenzene-induced contact hypersensitivity response. The concentration of pCS in blood was negatively correlated with the degree of the contact hypersensitivity response. In contrast, the T cell-dependent antibody response was not influenced by the accumulated pCS. We also examined the in vitro cytokine responses by T cells in the presence of pCS. The production of IFN-γ was suppressed by pCS. Further, pCS decreased the percentage of IFN-γ-producing Th1 cells. Our results suggest that intestinal bacteria-derived pCS suppressesTh1-type cellular immune responses. PMID:24161588

  11. Bioleaching of arsenic in contaminated soil using metal-reducing bacteria

    NASA Astrophysics Data System (ADS)

    Lee, So-Ra; Lee, Jong-Un; Chon, Hyo-Taek

    2014-05-01

    A study on the extraction of arsenic in the contaminated soil collected from an old smelting site in Korea was carried out using metal-reducing bacteria. Two types of batch-type experiments, biostimulation and bioaugmentation, were conducted for 28 days under anaerobic conditions. The biostimulation experiments were performed through activation of indigenous bacteria by supply with glucose or lactate as a carbon source. The contaminated, autoclaved soil was inoculated with metal-reducing bacteria, Shewanella oneidensis MR-1 and S. algae BrY, in the bioaugmentation experiments. The results indicated that the maximum concentration of the extracted As was 11.2 mg/L at 4 days from the onset of the experiment when 20 mM glucose was supplied and the extraction efficiency of As ranged 60~63% in the biostimulation experiments. In the case of bioaugmentation, the highest dissolved As concentration was 24.4 mg/L at 2 days, though it dramatically decreased over time through re-adsorption onto soil particles. After both treatments, mode of As occurrence in the soil appeared to be changed to readily extractable fractions. This novel technique of bioleaching may be practically applied for remediation of As-contaminated soil after determination of optimum operational conditions such as operation time and proper carbon source and its concentration.

  12. Microbial Reduction of Uranium under Iron- and Sulfate-reducing Conditions: Effect of Amended Goethite on Microbial Community Composition and Dynamics

    SciTech Connect

    Moon, Hee Sun; McGuinness, L.; Kukkadapu, Ravi K.; Peacock, Aaron D.; Komlos, John; Kerkhoff, Lee; Long, Philip E.; Jaffe, Peter R.

    2010-07-01

    There is a growing need for a better understanding of the biogeochemical dynamics involved in microbial U(VI) reduction due to an increasing interest in using biostimulation via electron donor addition as a means to remediate uranium contaminated sites. U(VI) reduction has been observed to be maximized during iron reducing conditions and to decrease upon commencement of sulfate reducing conditions. There are many unknowns regarding the impact of iron/sulfate biogeochemistry on U(VI) reduction. This includes Fe(III) availability as well as the microbial community changes, including the activity of iron-reducers during the uranium biostimulation period even after the onset of sulfate reduction. Up-flow column experiments were conducted with Old Rifle site sediments containing Fe-oxides, Fe-clays, and sulfate rich groundwater. Half of the columns had sediment that was augmented with small amounts of small-particle 57Fe-goethite to track continuously minute goethite changes, and to study the effects of increased Fe(III) levels on the overall biostimulation dynamics. The addition of the 57Fe-goethite did not delay the onset of sulfate reduction, but slightly suppressed the overall rate of sulfate reduction and hence acetate utilization, it did not affect the bacterial numbers of Geobacter-like species throughout the experiment, but did lower the numbers of sulfate reducers in the sediments. 57Fe-Mössbauer analyses (a 57Fe-specific technique) confirmed that there was bioavailable iron present after the onset of sulfate reduction and that iron was still being reduced during sulfate reduction. Addition of the 57Fe-goethite to the sediment had a noticeable effect on the overall composition of the microbial population. 16S rRNA analyses of biostimulated sediment using TRFLP (terminal restriction fragment length polymorphism) showed that Geobacter sp. (a known Fe-reducer) was still active and replicating during the period of significant sulfate reduction. DNA fingerprints of

  13. Rapid Discrimination of Gram-Positive and Gram-Negative Bacteria in Liquid Samples by Using NaOH-Sodium Dodecyl Sulfate Solution and Flow Cytometry

    PubMed Central

    Wada, Atsushi; Kono, Mari; Kawauchi, Sawako; Takagi, Yuri; Morikawa, Takashi; Funakoshi, Kunihiro

    2012-01-01

    Background For precise diagnosis of urinary tract infections (UTI), and selection of the appropriate prescriptions for their treatment, we explored a simple and rapid method of discriminating gram-positive and gram-negative bacteria in liquid samples. Methodology/Principal Findings We employed the NaOH-sodium dodecyl sulfate (SDS) solution conventionally used for plasmid extraction from Escherichia coli and the automated urine particle analyzer UF-1000i (Sysmex Corporation) for our novel method. The NaOH-SDS solution was used to determine differences in the cell wall structures between gram-positive and gram-negative bacteria, since the tolerance to such chemicals reflects the thickness and structural differences of bacterial cell walls. The UF-1000i instrument was used as a quantitative bacterial counter. We found that gram-negative bacteria, including E. coli, in liquid culture could easily be lysed by direct addition of equal volumes of NaOH-SDS solution. In contrast, Enterococcus faecalis, which is a gram-positive bacterium, could not be completely lysed by the solution. We then optimized the reaction time of the NaOH-SDS treatment at room temperature by using 3 gram-positive and 4 gram-negative bacterial strains and determined that the optimum reaction time was 5 min. Finally, in order to evaluate the generalizability of this method, we treated 8 gram-positive strains and 8 gram-negative strains, or 4 gram-positive and 4 gram-negative strains incubated in voluntary urine from healthy volunteers in the same way and demonstrated that all the gram-positive bacteria were discriminated quantitatively from gram negative bacteria using this method. Conclusions/Significance Using our new method, we could easily discriminate gram-positive and gram-negative bacteria in liquid culture media within 10 min. This simple and rapid method may be useful for determining the treatment course of patients with UTIs, especially for those without a prior history of UTIs. The method

  14. Plutonium Oxidation State Distribution under Aerobic and Anaerobic Subsurface Conditions for Metal-Reducing Bacteria

    NASA Astrophysics Data System (ADS)

    Reed, D. T.; Swanson, J.; Khaing, H.; Deo, R.; Rittmann, B.

    2009-12-01

    The fate and potential mobility of plutonium in the subsurface is receiving increased attention as the DOE looks to cleanup the many legacy nuclear waste sites and associated subsurface contamination. Plutonium is the near-surface contaminant of concern at several DOE sites and continues to be the contaminant of concern for the permanent disposal of nuclear waste. The mobility of plutonium is highly dependent on its redox distribution at its contamination source and along its potential migration pathways. This redox distribution is often controlled, especially in the near-surface where organic/inorganic contaminants often coexist, by the direct and indirect effects of microbial activity. The redox distribution of plutonium in the presence of facultative metal reducing bacteria (specifically Shewanella and Geobacter species) was established in a concurrent experimental and modeling study under aerobic and anaerobic conditions. Pu(VI), although relatively soluble under oxidizing conditions at near-neutral pH, does not persist under a wide range of the oxic and anoxic conditions investigated in microbiologically active systems. Pu(V) complexes, which exhibit high chemical toxicity towards microorganisms, are relatively stable under oxic conditions but are reduced by metal reducing bacteria under anaerobic conditions. These facultative metal-reducing bacteria led to the rapid reduction of higher valent plutonium to form Pu(III/IV) species depending on nature of the starting plutonium species and chelating agents present in solution. Redox cycling of these lower oxidation states is likely a critical step in the formation of pseudo colloids that may lead to long-range subsurface transport. The CCBATCH biogeochemical model is used to explain the redox mechanisms and final speciation of the plutonium oxidation state distributions observed. These results for microbiologically active systems are interpreted in the context of their importance in defining the overall migration

  15. Composition, Reactivity and Regulation of Extracellular Metal-Reducing Structures (Bacterial Nanowires) Produced by Dissimilatory Metal - Reducing Bacteria.

    SciTech Connect

    Beveridge, Terrance J; Whitfield, Christopher

    2013-03-06

    This is the final technical report for the project. There were two objectives in the proposal. The first was to describe the composition and function of electrically conductive appendages, known as bacterial nanowires, which resemble pili but are longer and are electrically conductive. They were first identified on the dissimilatory metal-reducing bacteria (DMRB), Shewanella and Geobacter. Specifically, this project investigated the role of these structures in: (i) the reductive transformation of iron oxides as solid phase electron acceptors; (ii) the use of as uranium as a dissolved electron acceptor to form nanocrystalline particles of uraninite upon reduction. The Beveridge group investigated these processes using advanced cryo-transmission electron microscopy (cryoTEM) to visualize the points of connection between the distal ends of nanowires and the effect they have on solid phase Fe minerals. At the same time, immuno-electron microscopy was applied in an attempt to identify where metal reductases and cytochromes are located on the cell surface, or in the nanowires. The second objective was to define the surface physicochemistry of Shewanella spp. in an attempt to decipher how weak bonding (electrostatics and hydrophobicity) affects the adherence of the bacteria to Fe oxides. This bonding could be dictated by the chemistry of lipopolysaccharide (LPS), or the presence/absence of capsular polysaccharide.

  16. Anaerobic 1-Alkene Metabolism by the Alkane- and Alkene-Degrading Sulfate Reducer Desulfatibacillum aliphaticivorans