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Sample records for sulfate reducing bacteria

  1. Growth of Sulfate-Reducing Bacteria in Sulfate Brines and the Astrobiological Implications for Mars

    NASA Astrophysics Data System (ADS)

    Marnocha, C. L.; Chevrier, V. F.; Ivey, D. M.

    2011-03-01

    We suggest sulfate-reducing bacteria as a model for life on Mars, as sulfate brines have been shown to be stable in martian conditions. We have performed experiments to determine the survivability of these bacteria in high sulfate concentrations.

  2. Versatile Medium for the Enumeration of Sulfate-Reducing Bacteria

    PubMed Central

    Postgate, John R.

    1963-01-01

    A lactate-yeast extract-sulfate medium, making use of both thioglycolate and ascorbate to poise the En gave valid colony counts of sulfate-reducing bacteria with both pure cultures and natural samples. PMID:13985693

  3. 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

  4. 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.

  5. 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…

  6. 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

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. Reduction of molybdate by sulfate-reducing bacteria.

    PubMed

    Biswas, Keka C; Woodards, Nicole A; Xu, Huifang; Barton, Larry L

    2009-02-01

    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. While molybdate is a structural analog of sulfate and inhibits sulfate respiration of SRB, little information is available concerning the effect of molybdate on pure cultures. We followed the growth of Desulfovibrio gigas ATCC 19364, Desulfovibrio vulgaris Hildenborough, Desulfovibrio 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, 395 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. PMID:19130259

  13. Sulfate-reducing bacteria impairs working memory in mice.

    PubMed

    Ritz, Nathaniel L; Burnett, Benjamin J; Setty, Prashanth; Reinhart, Katelyn M; Wilson, Melissa R; Alcock, Joe; Singh, Sudha B; Barton, Larry L; Lin, Henry C

    2016-04-01

    The ability of gut microbes to bi-directionally communicate with the brain and vice versa form the basis of the gut microbiome-central nervous system axis. It has been shown that inoculation with pathogenic gut bacteria alters the behavior of mice; however, it is not known whether or not non-pathogenic resident microbes have similar effects. In this study, we tested the hypothesis that the administration of sulfate-reducing bacteria (SRB), a specific group of resident gut bacteria that generate hydrogen sulfide (H2S), impair learning and memory performance in mice tested in an 8-arm radial maze and Morris water maze. We found that mice spent more time in the center of the maze when they were gavaged with live SRB as compared to mice given saline (control), lactulose+mannitol (L/M), or killed SRB. SRB-gavaged mice were also tested using the Morris water maze and were found to take longer to complete the test, spend more time further from the platform, and have a longer path length to reach the platform. This effect of SRB on maze performance was associated with a higher concentration of H2S in the small intestine and cecum. We conclude that SRB, a specific resident gut bacterial species, could impair cognitive function in mice. PMID:26861176

  14. Passive abatement of acid rock drainage by sulfate reducing bacteria

    SciTech Connect

    Thompson, D.N.; Sayer, R.L.; Noah, K.S.

    1996-10-01

    Passive treatment systems for Acid Rock Drainage (ARD) using wetland technology have been in development at eastern coal mines since the mid 1980s. Due to the high altitudes, remoteness, lack of large flat areas, and/or heavy metal levels at western mine sites, application of this technology has been lacking. This research explored whether pine sawdust can be used as sole carbon source in a smaller volume system for ARD remediation which can handle high throughputs. The technology utilizes sulfate reducing bacteria (SRB) to precipitate metal sulfides from their sulfates, while raising pH due to net consumption of H{sup +}. Laboratory results indicate that indigenous SRB are present in mud obtained from a northern Idaho mine site. With partially degraded lodgepole pine sawdust as carbon source, 50-99% reduction of various metals, and pH increases from 3 to about 7 were attained in ARD collected from mine seeps. Thus, this system appears promising as a long term, low cost/maintenance technology for ARD remediation at remote western mines.

  15. 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 analyses of metabolites with benzene-grown cultures, suggesting an activation of benzene via carboxylation.

  16. 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 3C 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 ?mol of sulfate/mg (dry weight) of SRB h?1) at 0.25 mM sulfate to 5.0 1.1 ?mol 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 ?mol 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

  17. 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.

  18. Potential for beneficial application of sulfate reducing bacteria in sulfate containing domestic wastewater treatment.

    PubMed

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

    2015-11-01

    The activity of sulfate reducing bacteria (SRB) in domestic wastewater treatment plants (WWTP) is often considered as a problem due to H2S formation and potential related odour and corrosion of materials. However, when controlled well, these bacteria can be effectively used in a positive manner for the treatment of wastewater. The main advantages of using SRB in wastewater treatment are: (1) minimal sludge production, (2) reduction of potential pathogens presence, (3) removal of heavy metals and (4) as pre-treatment of anaerobic digestion. These advantages are accessory to efficient and stable COD removal by SRB. Though only a few studies have been conducted on SRB treatment of domestic wastewater, the many studies performed on industrial wastewater provide information on the potential of SRB in domestic wastewater treatment. A key-parameter analyses literature study comprising pH, organic substrates, sulfate, salt, temperature and oxygen revealed that the conditions are well suited for the application of SRB in domestic wastewater treatment. Since the application of SRB in WWTP has environmental benefits its application is worth considering for wastewater treatment, when sulfate is present in the influent. PMID:26362530

  19. 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

  20. Ion chromatography for determination of metabolic patterns of sulfate-reducing bacteria

    SciTech Connect

    Lebel, A.; Yen, T.F.

    1984-04-01

    Ion exchange chromatography is used to monitor the concentration of ionic species in bacterial growth media. The ions of interest are sulfate, lactate, acetate, and carbonate. All of these ions play important roles in the metabolism of the desired bacteria. It is possible, using this monitoring technique, to explore the growth of sulfate-reducing bacteria of the Desulfovibrio genus.

  1. 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...

  2. 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.

  3. Community Size and Metabolic Rates of Psychrophilic Sulfate-Reducing Bacteria in Arctic Marine Sediments

    PubMed Central

    Knoblauch, Christian; Jørgensen, Bo Barker; Harder, Jens

    1999-01-01

    The numbers of sulfate reducers in two Arctic sediments with in situ temperatures of 2.6 and −1.7°C were determined. Most-probable-number counts were higher at 10°C than at 20°C, indicating the predominance of a psychrophilic community. Mean specific sulfate reduction rates of 19 isolated psychrophiles were compared to corresponding rates of 9 marine, mesophilic sulfate-reducing bacteria. The results indicate that, as a physiological adaptation to the permanently cold Arctic environment, psychrophilic sulfate reducers have considerably higher specific metabolic rates than their mesophilic counterparts at similarly low temperatures. PMID:10473441

  4. 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.

  5. Sulfate-reducing bacteria and their activities in cyanobacterial mats of Solar Lake (Sinai, Egypt)

    SciTech Connect

    Teske, A.; Ramsing, N.B.; Habicht, K.; Kuever, J.; Joergensen, B.B.; Fukui, Manabu; 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{sup 6} and 10{sup 7} cultivable sulfate-reducing bacteria ml{sup {minus}1} day{sup {minus}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{sup 4} and 10{sup 6} cells ml{sup {minus}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 CO{sub 2} from sulfate reduction in the upper 5 mm accounted for 7 to 8% of the total photosynthetic CO{sub 2} demand of the mat.

  6. Phylogenetic analysis of Syntrophobacter wolinii reveals a relationship with sulfate-reducing bacteria.

    PubMed

    Harmsen, H J; Wullings, B; Akkermans, A D; Ludwig, W; Stams, A J

    1993-01-01

    A 16S rRNA sequence analysis of Syntrophobacter wolinii was done by using PCR amplification of the 16S rRNA-genes from DNA isolated from the S. wolinii-Desulfovibrio sp. coculture. Phylogenetic analysis using the obtained sequence revealed that S. wolinii was not related to bacteria growing syntrophically on other fatty acids than propionate, but was related to sulfate-reducing bacteria. The closest related bacteria are Desulfomonile tiedjei and Desulfoarculus baarsii. PMID:7692834

  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. Anaerobic biodegradation of explosives and related compounds by sulfate-reducing and methanogenic bacteria : a review.

    SciTech Connect

    Boopathy, R.; Kulpa, C. F.; Manning, J.; Environmental Research; Univ. of Notre Dame

    1998-01-01

    In recent years, research on microbial degradation of explosives and nitroaromatic compounds has increased. Most studies of the microbial metabolism of nitroaromatic compounds have used aerobic microorganisms. 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. Few review papers exist, and those deal mainly with aerobic bacterial degradation of explosives; none deals with anaerobic bacteria. In this paper, we review the anaerobic metabolic processes in the degradation of explosives and nitroaromatic compounds under sulfate-reducing and methanogenic conditions.

  9. 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

  10. 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.

  11. 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.

  12. 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....

  13. 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...

  14. 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...

  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. 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 ...

  17. Activity and diversity of sulfate-reducing bacteria in a petroleum hydrocarbon-contaminated aquifer.

    PubMed

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

    2002-04-01

    Microbial sulfate reduction is an important metabolic activity in petroleum hydrocarbon (PHC)-contaminated aquifers. We quantified carbon source-enhanced microbial SO(4)(2-) 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 indicated that the bacterial community structure of the dominant species did not change during the tests. Thus, the combination of push-pull tests with molecular methods provided valuable insights into microbial processes, activities, and diversity in the sulfate-reducing zone of a PHC-contaminated aquifer. PMID:11916663

  18. [Biodiversity of sulfate-reducing bacteria growing on objects of heating systems].

    PubMed

    Purish, L M; Asaulenko, L G; Abdulina, D R; Iutinskaia, G A

    2014-01-01

    It was shown that sulfate-reducing bacteria developed on the sections of Kyiv municipal heating systems, which are exploited in conditions of different temperatures. The bacteria were different as to their morphological and physiological properties. The bacteria of Desulfovibrio genus were revealed on the sections, which were exploited at a temperature of 35-40 degrees C and bacteria of Desulfomicrobium and Desulfotomaculum genera were revealed on the sections with a higher temperature such as 60 degrees C. Based on of the 16S rRNA gene analysis data, it was demonstrated that sequences of TC2, TC3 and TC4 clones related to Desulfovibrio sp. DSM 12803 (100% sequence similarity), Desulfotomaculum sp. ECP-C-5 (92% sequence similarity) and Desulfomicrobium baculatum strain DSM 2555 (99% sequence similarity), respectively. The identified bacteria are potentially dangerous for heating systems and can be the agents of microbial corrosion. PMID:25007438

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. 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.

    1995-10-01

    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.

  4. 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.

  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. 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

  7. Carbon isotope fractionation by sulfate-reducing bacteria using different pathways for the oxidation of acetate.

    PubMed

    Goevert, Dennis; Conrad, Ralf

    2008-11-01

    Acetate is a key intermediate in the anaerobic degradation of organic matter. In anoxic environments, available acetate is a competitive substrate for sulfate-reducing bacteria (SRB) and methane-producing archaea. Little is known about the fractionation of carbon isotopes by sulfate reducers. Therefore, we determined carbon isotope compositions in cultures of three acetate-utilizing SRB, Desulfobacter postgatei, Desulfobacter hydrogenophilus, and Desulfobacca acetoxidans. We found that these species showed strong differences in their isotope enrichment factors (epsilon) of acetate. During the consumption of acetate and sulfate, acetate was enriched in 13C by 19.3% per hundred in Desulfobacca acetoxidans. By contrast, both D. postgatei and D. hydrogenophilus showed a slight depletion of 13C resulting in epsilon(ac)-values of 1.8 and 1.5% per hundred, respectively. We suggest that the different isotope fractionation is due to the different metabolic pathways for acetate oxidation. The strongly fractionating Desulfobacca acetoxidans uses the acetyl-CoA/carbon monoxide dehydrogenase pathway, which is also used by acetoclastic methanogens that show a similar fractionation of acetate (epsilon(ac) = -21 to -27% per hundred). In contrast, Desulfobacter spp. oxidize acetate to CO2 via the tricarboxylic acid (TCA) cycle and apparently did not discriminate against 13C. Our results suggestthat carbon isotope fractionation in environments with sulfate reduction will strongly depend on the composition of the sulfate-reducing bacterial community oxidizing acetate. PMID:19031865

  8. 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

  9. 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, deepsea hydrothermal vents, soda and high salinity lakes, and cryo-environments. Furthermore, the StRB and SrRB have Astrobiological significance as these anaerobic extremophiles may represent the dominant relic life forms that inhabited our planet during the extensive volcanic activity in the Earth's early evolutionary period.

  10. 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.

  11. A Cultured Greigite-Producing Magnetotactic Bacterium in a Novel Group of Sulfate-Reducing Bacteria

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

    Magnetotactic bacteria contain magnetosomes—intracellular, membrane-bounded, magnetic nanocrystals of magnetite (Fe3O4) or greigite (Fe3S4)—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.

  12. 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

  13. Suitability of different growth substrates as source of nitrogen for sulfate reducing bacteria.

    PubMed

    Dev, Subhabrata; Patra, Aditya Kumar; Mukherjee, Abhijit; Bhattacharya, Jayanta

    2015-11-01

    Sulfate reducing bacteria (SRB) mediated treatment of acid mine drainage is considered as a globally accepted technology. However, inadequate information on the role of nitrogen source in the augmentation of SRB significantly affects the overall treatment process. Sustenance of SRB depends on suitable nitrogen source which is considered as an important nutrient. This review focuses on the different nitrogen rich growth substrates for their effectiveness to support SRB growth and sulfate reduction in passive bioreactors. Compounds like NH4Cl, NH4HCO3, NO3 (-), aniline, tri-nitrotoluene, cornsteep liquor, peptone, urea, and chitin are reported to have served as nitrogen source for SRB. In association with fermentative bacteria, SRB can metabolize these complex compounds to NH4 (+), amines, and amino acids. After incorporation into cells, these compounds take part in the biosynthesis of nucleic acids, amino acids and enzyme co-factor. This work describes the status of current and the probable directions of the future research. PMID:26364194

  14. 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 of meters above. PMID:22363336

  15. 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

  16. 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

  17. 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

  18. 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.

  19. 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.

  20. 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 with HgS "clusters", thereby stabilizing the clusters and slowing the rate of formation of larger nanoparticles. In so doing, the HgS species remain relatively small and disordered, and available for uptake by sulfate-reducing bacteria.

  1. 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.

  2. Evidence for Coexistence of Two Distinct Functional Groups of Sulfate-Reducing Bacteria in Salt Marsh Sediment

    PubMed Central

    Banat, Ibrahim M.; Lindström, E. Börje; Nedwell, David B.; Balba, M. Talaat

    1981-01-01

    Oxidation of acetate in salt marsh sediment was inhibited by the addition of fluoroacetate, and also by the addition of molybdate, an inhibitor of sulfate-reducing bacteria. Molybdate had no effect upon the metabolism of acetate in a freshwater sediment in the absence of sulfate. The inhibitory effect of molybdate on acetate turnover in the marine sediment seemed to be because of its inhibiting sulfate-reducing bacteria which oxidized acetate to carbon dioxide. Sulfide was not recovered from sediment in the presence of molybdate added as an inhibitor of sulfate-reducing bacteria, but sulfide was recovered quantitatively even in the presence of molybdate by the addition of the strong reducing agent titanium chloride before acidification of the sediment. Reduction of sulfate to sulfide by the sulfate-reducing bacteria in the sediment was only partially inhibited by fluoroacetate, but completely inhibited by molybdate addition. This was interpreted as showing the presence of two functional groups of sulfate-reducing bacteria—one group oxidizing acetate, and another group probably oxidizing hydrogen. PMID:16345910

  3. 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.

  4. Analyses of spatial distributions of sulfate-reducing bacteria and their activity in aerobic wastewater biofilms

    SciTech Connect

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

    1999-11-01

    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 O{sub 2}, H{sub 2}S, NO{sub 2}{minus}, NH{sub 2}{sup +}, 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 were evenly distributed throughout the biofilm, even in the toxic surface. The probe SRB660-stained Desulfobulbus spp. were found to be numerically important members of SRB populations. The result of microelectrode measurements showed that a high sulfate-reducing activity was found in a narrow anaerobic zone located about 150 to 300 {micro}m below the biofilm surface and above which an intensive sulfide oxidation zone was found. The biogeochemical measurements showed that elemental sulfur (S{degree}) was an important intermediate of the sulfide reoxidation in such thin wastewater biofilms, 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.

  5. Contribution of coexisting sulfate and iron reducing bacteria to methylmercury production in freshwater river sediments.

    PubMed

    Yu, Ri-Qing; Flanders, J R; Mack, E Erin; Turner, Ralph; Mirza, M Bilal; Barkay, Tamar

    2012-03-01

    We investigated microbial methylmercury (CH(3)Hg) production in sediments from the South River (SR), VA, an ecosystem contaminated with industrial mercury (Hg). Potential Hg methylation rates in samples collected at nine sites were low in late spring and significantly higher in late summer. Demethylation of (14)CH(3)Hg was dominated by (14)CH(4) production in spring, but switched to producing mostly (14)CO(2) in the summer. Fine-grained sediments originating from the erosion of river banks had the highest CH(3)Hg concentrations and were potential hot spots for both methylation and demethylation activities. Sequencing of 16S rRNA genes of cDNA recovered from sediment RNA extracts indicated that at least three groups of sulfate-reducing bacteria (SRB) and one group of iron-reducing bacteria (IRB), potential Hg methylators, were active in SR sediments. SRB were confirmed as a methylating guild by amendment experiments showing significant sulfate stimulation and molybdate inhibition of methylation in SR sediments. The addition of low levels of amorphous iron(III) oxyhydroxide significantly stimulated methylation rates, suggesting a role for IRB in CH(3)Hg synthesis. Overall, our studies suggest that coexisting SRB and IRB populations in river sediments contribute to Hg methylation, possibly by temporally and spatially separated processes. PMID:22148328

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. Biodesulfurization of flue gases and other sulfate/sulfite waste streams using immobilized mixed sulfate-reducing bacteria.

    PubMed

    Selvaraj, P T; Little, M H; Kaufman, E N

    1997-01-01

    Sulfur dioxide (SO2) is one of the major pollutants in the atmosphere that cause acid rain. Microbial processes for reducing SO2 to hydrogen sulfide (H2S) have previously been demonstrated by utilizing mixed cultures of sulfate-reducing bacteria (SRB) with municipal sewage digest as the carbon and energy source. To maximize the productivity of the bioreactor for SO2 reduction in this study, various immobilized cell bioreactors were investigated: a stirred tank with SRB flocs and columnar reactors with cells immobilized in either potassium-carrageenan gel matrix or polymeric porous BIO-SEP beads. The maximum volumetric productivity for SO2 reduction in the continuous stirred-tank reactor (CSTR) with SRB flocs was 2.1 mmol of SO2/(h.L). The potassium-carrageenan gell matrix used for cell immobilization was not durable at feed sulfite concentrations greater than 2000 mg/L (1.7 mmol/(h.L)). A columnar reactor with mixed SRB cells that had been allowed to grow into highly stable BIO-SEP polymeric beads exhibited the highest sulfite conversion rates, in the range 16.5 mmol/(h.L) (with 100% conversion) to 20 mmol/(h.L) (with 95% conversion). The average specific activity for sulfite reduction in the column, in terms of dry weight of SRB biomass, was 9.5 mmol of sulfite/(h.g). In addition to flue gas desulfurization, potential applications of this microbial process include the treatment of sulfate/sulfite-laden wastewater from the pulp and paper, petroleum, mining, and chemical industries. PMID:9376112

  12. New Family of Tungstate-Responsive Transcriptional Regulators in Sulfate-Reducing Bacteria

    PubMed Central

    Rajeev, Lara; Luning, Eric G.; Zane, Grant M.; Siddartha, Kavya; Rodionov, Dmitry A.; Dubchak, Inna; Arkin, Adam P.; Wall, Judy D.; Mukhopadhyay, Aindrila

    2013-01-01

    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

  13. 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.

  14. 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

  15. 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.

  16. Method for studying stabilization of localized corrosion on carbon steel by sulfate-reducing bacteria

    SciTech Connect

    Campaignolle, X.; Crolet, J.L.

    1997-06-01

    Initiation of a corrosion pit in plain carbon steel (CS) was simulated by preconditioning a small area and a larger concentric area as an anode and cathode, respectively. Preconditioning was achieved by applying a galvanic current between the electrodes. During this initial step, the effect of sulfate-reducing bacteria (SRB) on resulting polarization of this artificial galvanic cell was investigated. The previously conditioned electrodes then were left short-circuited, and the naturally flowing galvanic current was measured using a zero-resistance ammeter. In the presence of SRB biofilms, an active and naturally stable galvanic cell was achieved. In sterile conditions, the coupling current either was unstable or very low. This technique was aimed at studying risk factors linking bacterial contamination to the onset of rapid pitting corrosion.

  17. Demethylation of dimethylsulfoniopropionate to 3-S-methylmercaptopropionate by marine sulfate-reducing bacteria.

    PubMed Central

    van der Maarel, M J; Jansen, M; Haanstra, R; Meijer, W G; Hansen, T A

    1996-01-01

    The initial step in the anaerobic degradation of the algal osmolyte dimethylsulfoniopropionate (DMSP) in anoxic marine sediments involves either a cleavage to dimethylsulfide and acrylate or a demethylation to 3-S-methylmercaptopropionate. Thus far, only one anaerobic bacterial strain has been shown to carry out the demethylation, namely, Desulfobacterium sp. strain PM4. The aims of the present work were to study how common this property is among certain groups of anaerobic bacteria and to obtain information on the affinities for DMSP of DMSP-demethylating strains. Screening of several pure cultures of sulfate-reducing and acetogenic bacteria showed that Desulfobacterium vacuolatum DSM 3385 and Desulfobacterium niacini DSM 2059 are also able to demethylate DMSP; a very slow demethylation of DMSP was observed with a salt-tolerant strain of Eubacterium limosum. From a 10(5) dilution of intertidal sediment a new marine DMSP-demethylating sulfate-reducing bacterium (strain WN) was isolated. Strain WN was a short, gram-negative, nonmotile rod that grew on betaine, sarcosine, palmitate, H2 plus CO2, and several alcohols, organic acids, and amino acids. Extracts of betaine-grown cells had hydrogenase, formate dehydrogenase, and CO dehydrogenase activities but no alpha-ketoglutarate oxidoreductase activity, indicating the presence of the acetyl coenzyme A-CO dehydrogenase pathway. Analysis of the 16S rRNA gene sequence of strain WN revealed a close relationship with Desulfobacter hydrogenophilus, Desulfobacter latus, and Desulfobacula toluolica. Strain PM4 was shown to group with Desulfobacterium niacini. The K(m) of strain WN for DMSP, as derived from substrate progress curves in cell suspensions, was approximately 10 microM. A similar value was found for D. niacini PM4. PMID:8899985

  18. Phylogenetic tree of 16s rRNA sequences from sulfate-reducing bacteria in a sandy marine sediment

    SciTech Connect

    Devereux, R.; Mundfrom, G.W.

    1994-01-01

    Phylogenetic divergence among sulfate-reducing bateria in an estuarine sediment sample was investigated by PCR amplification and comparison of partial 16S rDNA sequences. Twenty unique 16S rDNA sequences were found, 12 from delta subclass bacteria based on overall sequence similarity (82-91%). Two successive PCR amplifications were used to obtain and clone the 16S rDNA. The first reaction used templates derived from phosphate-buffered saline washed sediment with primers designed to amplify nearly full-length bacterial domain 16S rDNA. A produce from a first reaction was used as template in a second reaction with primers designed to selectivity amplify a region of 16S rDNA genes of sulfate-reducing bacteria. A phylogenetic tree incorporating the cloned sequences suggests the presence of yet to be cultivated lines of sulfate-reducing bacteria within the sediment sample.

  19. 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 out after As exposure. Citation: DC.Rubin SS, Alava P, Zekker I, Du Laing G, Van de Wiele T. 2014. Arsenic thiolation and the role of sulfate-reducing bacteria from the human intestinal tract. Environ Health Perspect 122:817–822; http://dx.doi.org/10.1289/ehp.1307759 PMID:24833621

  20. 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

  1. 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.

  2. Modeling in-situ uranium(VI) bioreduction by sulfate-reducing bacteria

    NASA Astrophysics Data System (ADS)

    Luo, Jian; Weber, Frank-Andreas; Cirpka, Olaf A.; Wu, Wei-Min; Nyman, Jennifer L.; Carley, Jack; Jardine, Philip M.; Criddle, Craig S.; Kitanidis, Peter K.

    2007-06-01

    We present a travel-time based reactive transport model to simulate an in-situ bioremediation experiment for demonstrating enhanced bioreduction of uranium(VI). The model considers aquatic equilibrium chemistry of uranium and other groundwater constituents, uranium sorption and precipitation, and the microbial reduction of nitrate, sulfate and U(VI). Kinetic sorption/desorption of U(VI) is characterized by mass transfer between stagnant micro-pores and mobile flow zones. The model describes the succession of terminal electron accepting processes and the growth and decay of sulfate-reducing bacteria, concurrent with the enzymatic reduction of aqueous U(VI) species. The effective U(VI) reduction rate and sorption site distributions are determined by fitting the model simulation to an in-situ experiment at Oak Ridge, TN. Results show that (1) the presence of nitrate inhibits U(VI) reduction at the site; (2) the fitted effective rate of in-situ U(VI) reduction is much smaller than the values reported for laboratory experiments; (3) U(VI) sorption/desorption, which affects U(VI) bioavailability at the site, is strongly controlled by kinetics; (4) both pH and bicarbonate concentration significantly influence the sorption/desorption of U(VI), which therefore cannot be characterized by empirical isotherms; and (5) calcium-uranyl-carbonate complexes significantly influence the model performance of U(VI) reduction.

  3. Anaerobic biotransformation of fluorene and phenanthrene by sulfate-reducing bacteria and identification of biotransformation pathway.

    PubMed

    Tsai, Jen-Chieh; Kumar, Mathava; Lin, Jih-Gaw

    2009-05-30

    In the present study, anaerobic biotransformation of fluorene and phenanthrene by sulfate-reducing bacteria (SRB) was investigated and biotransformation pathways were proposed. SRB was enriched from anaerobic swine wastewater sludge and its abundance was determined by the fluorescence in situ hybridization (FISH) technique. Batch anaerobic biotransformation studies were conducted with fluorene (5 mg L(-1)), phenanthrene (5 mg L(-1)) and a mixture of the two (10 mg L(-1)). After 21d of incubation, 88% of fluorene and 65% of phenanthrene were biotransformed by SRB. In contrast to previous studies, a decrease in biotransformation efficiency was observed in the presence of both fluorene and phenanthrene. Throughout the study, sulfate reduction was coupled with biotransformation of fluorene and phenanthrene. However, no increase in bacterial cell density was observed in the presence of an inhibitor, i.e. molybdate. Identification of metabolites by gas chromatography-mass spectrometry (GC-MS) revealed that fluorene and phenanthrene were biotransformed through a sequence of hydration and hydrolysis reactions followed by decarboxylation with the formation of p-cresol (only in the phenanthrene system) and phenol. The metabolites identified suggest novel biotransformation pathways of fluorene and phenenthrene. PMID:18848395

  4. Geolipids produced by methanogens and sulfate-reducing bacteria at the Lost City Hydrothermal Field

    NASA Astrophysics Data System (ADS)

    Bradley, A. S.; Hayes, J. M.; Summons, R. E.

    2003-12-01

    Molecular biomarkers document the presence in a geologic system of particular microbial lineages, or of microbes that use specific metabolic processes. Lipid extracts from carbonate rocks of the Lost City Hydrothermal Field yield a predominance of biomarkers diagnostic for methanogenic archaea including the ether lipids archaeol, sn-2 and sn-3 hydroxyarchaeol, and dihydroxyarchaeol and the hydrocarbon 2,6,10,15,19-pentamethylicosane (PMI). Sterols and hopanoids, diagnostic for eukaryotes and bacteria respectively, were subordinate. At ten sites surveyed thus far, biomarker types were not correlated with vent temperature or activity. Hydroxyarchaeols were detected in three active (T >= 70° C) and two inactive vents. Glycerol monoethers with saturated and unsaturated C15-C20 n-alkyl chains, diagnostic for sulfate-reducing bacteria, were detected in five active and three inactive vents. Carbohydrates were detected in four active vents, but not in the inactive vents. High concentrations of sn-2 and sn-3 hydroxyarchaeol and a dihydroxyarchaeol at a 70° C site (sample 3869-1404) suggest that methane cycling is the dominant metabolic processes at this location. The presence of methanogens at this site is confirmed by the presence of pentamethylicosane. Stable isotopic compositions of these biomarkers will be used to determine whether these methanogens are consuming or producing methane. This sample also contains C16 and C18 saturated glycerol monoethers. In conjunction with genomic studies, the biomarker analyses will document the metabolic roles of microbes in this system.

  5. Immunological Cross-Reactivities of Adenosine-5′-Phosphosulfate Reductases from Sulfate-Reducing and Sulfide-Oxidizing Bacteria

    PubMed Central

    Odom, J. Martin; Jessie, Karen; Knodel, Elinor; Emptage, Mark

    1991-01-01

    Crude extracts from 14 species of sulfate-reducing bacteria comprising the genera Desulfovibrio, Desulfotomaculum, Desulfobulbus, and Desulfosarcina and from three species of sulfide-oxidizing bacteria were tested in an enzyme-linked immunosorbent assay with polyclonal antisera to adenosine 5′-phosphosulfate reductase from Desulfovibrio desulfuricans G100A. The results showed that extracts from Desulfovibrio species were all highly cross-reactive, whereas extracts from the other sulfate-reducing genera showed significantly less cross-reaction. An exception was Desulfotomaculum orientis, which responded more like Desulfovibrio species than the other Desulfotomaculum strains tested. Extracts from colorless or photosynthetic sulfur bacteria were either unreactive or exhibited very low levels of reactivity with the antibodies to the enzyme from sulfate reducers. These results were confirmed by using partially purified enzymes from sulfate reducers and the most cross-reactive sulfide oxidizer, Thiobacillus denitrificans. Two types of monoclonal antibodies to adenosine 5′-phosphosulfate reductase were also isolated. One type reacted more variably with the enzymes of the sulfate reducers and poorly with the Thiobacillus enzyme, whereas the second reacted strongly with Desulfovibrio, Desulfotomaculum orientis, and Thiobacillus enzymes. Images PMID:16348440

  6. Marine sulfate-reducing bacteria cause serious corrosion of iron under electroconductive biogenic mineral crust

    PubMed Central

    Enning, Dennis; Venzlaff, Hendrik; Garrelfs, Julia; Dinh, Hang T; Meyer, Volker; Mayrhofer, Karl; Hassel, Achim W; Stratmann, Martin; Widdel, Friedrich

    2012-01-01

    Iron (Fe0) corrosion in anoxic environments (e.g. inside pipelines), a process entailing considerable economic costs, is largely influenced by microorganisms, in particular sulfate-reducing bacteria (SRB). The process is characterized by formation of black crusts and metal pitting. The mechanism is usually explained by the corrosiveness of formed H2S, and scavenge of ‘cathodic’ H2 from chemical reaction of Fe0 with H2O. Here we studied peculiar marine SRB that grew lithotrophically with metallic iron as the only electron donor. They degraded up to 72% of iron coupons (10 mm × 10 mm × 1 mm) within five months, which is a technologically highly relevant corrosion rate (0.7 mm Fe0 year−1), while conventional H2-scavenging control strains were not corrosive. The black, hard mineral crust (FeS, FeCO3, Mg/CaCO3) deposited on the corroding metal exhibited electrical conductivity (50 S m−1). This was sufficient to explain the corrosion rate by electron flow from the metal (4Fe0 → 4Fe2+ + 8e−) through semiconductive sulfides to the crust-colonizing cells reducing sulfate (8e− + SO42− + 9H+ → HS− + 4H2O). Hence, anaerobic microbial iron corrosion obviously bypasses H2 rather than depends on it. SRB with such corrosive potential were revealed at naturally high numbers at a coastal marine sediment site. Iron coupons buried there were corroded and covered by the characteristic mineral crust. It is speculated that anaerobic biocorrosion is due to the promiscuous use of an ecophysiologically relevant catabolic trait for uptake of external electrons from abiotic or biotic sources in sediments. PMID:22616633

  7. 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...

  8. 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 ...

  9. 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...

  10. 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...

  11. 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...

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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

  17. 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

  18. 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

  19. 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 water supply infrastructure. PMID:26098899

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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.

  5. A novel sulfate-reducing bacteria detection method based on inhibition of cysteine protease activity.

    PubMed

    Qi, Peng; Zhang, Dun; Wan, Yi

    2014-11-01

    Sulfate-reducing bacteria (SRB) have been extensively studied in corrosion and environmental science. However, fast enumeration of SRB population is still a difficult task. This work presents a novel specific SRB detection method based on inhibition of cysteine protease activity. The hydrolytic activity of cysteine protease was inhibited by taking advantage of sulfide, the characteristic metabolic product of SRB, to attack active cysteine thiol group in cysteine protease catalytic sites. The active thiol S-sulfhydration process could be used for SRB detection, since the amount of sulfide accumulated in culture medium was highly related with initial bacterial concentration. The working conditions of cysteine protease have been optimized to obtain better detection capability, and the SRB detection performances have been evaluated in this work. The proposed SRB detection method based on inhibition of cysteine protease activity avoided the use of biological recognition elements. In addition, compared with the widely used most probable number (MPN) method which would take up to at least 15days to accomplish whole detection process, the method based on inhibition of papain activity could detect SRB in 2 days, with a detection limit of 5.21×10(2) cfu mL(-1). The detection time for SRB population quantitative analysis was greatly shortened. PMID:25127594

  6. 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

  7. 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.

  8. A XPS Study of the Passivity of Stainless Steels Influenced by Sulfate-Reducing Bacteria.

    NASA Astrophysics Data System (ADS)

    Chen, Guocun

    The influence of sulfate-reducing bacteria (SRB) on the passivity of type 304 and 317L stainless steels (SS) was investigated by x-ray photoelectron spectroscopy (XPS), microbiological and electrochemical techniques. Samples were exposed to SRB, and then the resultant surfaces were analyzed by XPS, and the corrosion resistance by potentiodynamic polarization in deaerated 0.1 M HCl. To further understand their passivity, the SRB-exposed samples were analyzed by XPS after potentiostatic polarization at a passive potential in the hydrochloric solution. The characterization was performed under two surface conditions: unrinsed and rinsed by deaerated alcohol and deionized water. Comparisons were made with control samples immersed in uninoculated medium. SRB caused a severe loss of the passivity of 304 SS through sulfide formation and possible additional activation to form hexavalent chromium. The sulfides included FeS, FeS_2, Cr_2S _3, NiS and possibly Fe_ {rm 1-x}S. The interaction took place nonuniformly, resulting in undercutting of the passive film and preferential hydration of inner surface layers. The bacterial activation of the Cr^{6+ }^ecies was magnified by subsequent potentiostatic polarization. In contrast, 317L SS exhibited a limited passivity. The sulfides were formed mainly in the outer layers. Although Cr^{6+}^ecies were observed after the exposure, they were dissolved upon polarization. Since 317L SS has a higher Mo content, its higher passivity was ascribed to Mo existing as molybdate on the surface and Mo^{5+} species in the biofilm. Consequently, the interaction of SRB with Mo was studied. It was observed that molybdate could be retained on the surfaces of Mo coupons by corrosion products. In the presence of SRB, however, a considerable portion of the molybdate interacted with intermediate sulfur -containing proteins, forming Mo(V)-S complexes and reducing bacterial growth and sulfate reduction. The limited insolubility of the Mo(V)-S complexes in 0.1 M HCl provided a certain protection so that the pitting potential of the SRB-exposed Mo coupons was not considerably decreased. The interaction of the sulfur-containing proteins with Mo also provided mechanistic information about the adhesion of biofilm to Mo-bearing steels. Additionally, the interactions of SRB with other alloying elements, Cr and Ni, were investigated.

  9. 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.

  10. Mercury methylation independent of the acetyl-coenzyme A pathway in sulfate-reducing bacteria.

    PubMed

    Ekstrom, Eileen B; Morel, François M M; Benoit, Janina M

    2003-09-01

    Sulfate-reducing bacteria (SRB) in anoxic waters and sediments are the major producers of methylmercury in aquatic systems. Although a considerable amount of work has addressed the environmental factors that control methylmercury formation and the conditions that control bioavailability of inorganic mercury to SRB, little work has been undertaken analyzing the biochemical mechanism of methylmercury production. The acetyl-coenzyme A (CoA) pathway has been implicated as being key to mercury methylation in one SRB strain, Desulfovibrio desulfuricans LS, but this result has not been extended to other SRB species. To probe whether the acetyl-CoA pathway is the controlling biochemical process for methylmercury production in SRB, five incomplete-oxidizing SRB strains and two Desulfobacter strains that do not use the acetyl-CoA pathway for major carbon metabolism were assayed for methylmercury formation and acetyl-CoA pathway enzyme activities. Three of the SRB strains were also incubated with chloroform to inhibit the acetyl-CoA pathway. So far, all species that have been found to have acetyl-CoA activity are complete oxidizers that require the acetyl-CoA pathway for basic metabolism, as well as methylate mercury. Chloroform inhibits Hg methylation in these species either by blocking the methylating enzyme or by indirect effects on metabolism and growth. However, we have identified four incomplete-oxidizing strains that clearly do not utilize the acetyl-CoA pathway either for metabolism or mercury methylation (as confirmed by the absence of chloroform inhibition). Hg methylation is thus independent of the acetyl-CoA pathway and may not require vitamin B(12) in some and perhaps many incomplete-oxidizing SRB strains. PMID:12957930

  11. 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

  12. 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

  13. 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.

  14. Pyrrhotite: an Iron Sulfide Mineral Formed During Growth of Sulfate-Reducing Bacteria at a Hematite Surface

    NASA Astrophysics Data System (ADS)

    Geesey, G.; Reardon, C.; Neal, A.

    2008-12-01

    Many bacteria are capable of respiring on sulfate and other oxidized forms of sulfur under anaerobic conditions. The hydrogen sulfide that is formed during dissimilatory sulfate reduction (DSR) readily reacts with metals in the surrounding environment to form insoluble metal sulfides. Iron oxides are common substrata for colonization by sulfate-reducing bacteria (SRB) in sedimentary aquatic systems as well as in subsurface environments. While numerous studies have characterized iron sulfides formed during dissimilatory sulfate reduction by suspended populations of these bacteria in the presence of soluble iron, not much is known about those formed in the presence of biofilm populations associated with solid phase iron, particularly crystalline forms such as hematite. Under the latter conditions, we have observed the formation of the iron sulfide pyrrhotite, typically present in very low abundance in sediments and ore deposits compared to pyrite. The formation of pyrrhotite over pyrite is favored at low redox potential and sulfide activity, conditions we hypothesize are achieved at an iron oxide surface colonized by biofilm-forming SRB. Higher levels of hydrogenase activity by hematite surface-associated SRB than suspended cell populations likely promotes the low redox potential that favors pyrrhotite formation. The tendency for SRB in nature to associate with mineral particle surfaces, including iron oxides, suggests that some pyrrotite may have originated through biotic reactions. A comparison of the fine structure of pyrrhotite formed through these biotic processes with that formed under abiotic processes may reveal differences that provide a signature for biotically-derived pyrrhotite in the biosphere.

  15. 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. Desulfobactor sp. BG8) grown in planktonic and biofilm form, as the acetyl- coenzyme A pathway involved with cobalamin has been hypothesized to be the pathway for Hg methylation. The purpose of this study was to probe whether differences in the enzymatically catalyzed process caused differential methylation rates between the species and also between the different forms of culture growth. Any attempts to control the environmentally undesirable Hg methylation process would benefit from a better understanding of the biochemical mechanism involved.

  16. 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

  17. 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...

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. Role of methanogenic and sulfate-reducing bacteria in the reductive dechlorination of tetrachloroethylene in mixed culture

    SciTech Connect

    Cabirol, N.; Perrier, J.; Jacob, F.

    1996-05-01

    Tetrachloroethylene (perchloroethylene, PCE) is widely used in many industries and particularly as a degreasing and dry-cleaning solvent. It is commonly found as a groundwater contaminant and because of its carcinogenic properties is considered a pollutant, which must be eliminated by proper treatment. This research examines the role of a mixed culture in PCE dechlorination at high concentration from an ecological point of view. The respective role of sulfate-reducing and methaogenic bacteria in tetrachloroethylene cechlorination is studied. 19 refs., 5 figs., 2 tabs.

  4. 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%.

  5. 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...

  6. [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

  7. 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.

  8. 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.

  9. [Effect of sulfate-reducing bacteria on steel corrosion in the presence of inhibitors].

    PubMed

    Purish, L M; Pogrebova, I S; Kozlova, I A

    2002-01-01

    Steel 08KP corrosion was studied as affected by inhibitors in presence of sulphate-reducing bacteria (SRB). Organic compounds, containing functional groups with nitrogen, oxygen and sulphur atoms, were investigated as corrosion inhibitors. It is shown that the studied inhibitors may be divided into three groups as to the mechanism of protective action. It has been established that cation-active nitrogen-containing surfactants ([symbol: see text] X, [symbol: see text]-1, [symbol: see text]-1M, catapin M, [symbol: see text]-2M) are the most efficient steel corrosion inhibitors. Such inhibitors, when adsorbed on metal surface, can affect the process of hydrogen precipitation on its surface, and thus inhibit catalytic function of SRB as the depolarizer of cathode process. PMID:12664553

  10. 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.

  11. 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

  12. 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

  13. 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

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

    PubMed

    Vester; Ingvorsen

    1998-05-01

    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 x 10(-10) to 7 x 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

  15. 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

  16. 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.

  17. Anaerobic degradation of alkylbenzenes in crude oil. I. Isolation and characterization of alkylbenzene-degrading sulfate-reducing and denitrifying bacteria

    SciTech Connect

    Rabus, R.; Aeckerberg, F.; Zengler, K.

    1996-10-01

    Marine, sulfate-reducing bacteria have been enriched from the water phase of a North Sea-oil tank. The enrichment culture grew on crude oil at the expense of alkylbenzenes with concomitant production of hydrogen sulfide. Whole cell hybridization with fluorescent oligonucleotide probes revealed that the enrichment culture consisted mainly of completely oxidizing sulfate-reducing bacteria. The findings demonstrate that alkylbenzenes in crude oil can be regarded as potential electron donors for sulfate-reduction in oil fields. The resulting formation of hydrogen sulfide may lead to souring of oil and corrosion of pipelines, In addition, we examined denitrifying bacteria. New types of dentrifying bacteria, which were isolated from fresh water sediments with various alkylbenzenes, grew on crude oil as the only source of organic substrates and nitrate as electron acceptor. In agreement with the nutritional capacities of the different bacterial strains, the pattern of alkylbenzene utilization from the crude oil was shown to be strain-specific.

  18. Combination of high throughput cultivation and dsrA sequencing for assessment of sulfate-reducing bacteria diversity in sediments.

    PubMed

    Colin, Yannick; Goñi-Urriza, Marisol; Caumette, Pierre; Guyoneaud, Rémy

    2013-01-01

    Improving the knowledge on sulfate-reducing bacteria (SRB) diversity and ecophysiology will permit a better understanding on their key roles in aquatic ecosystems. Therefore, their diversity was evaluated in estuarine sediments by a polyphasic approach including dsrA gene cloning and sequencing (156 clones) and high-throughput isolations in 384-well microplates (177 strains). Using the related thresholds of 95% (DsrA amino acid sequences) and 97% (16S rRNA gene sequences) for sequence similarity, SRB were grouped into 60 and 22 operational taxonomic units, respectively. Both approaches poorly overlapped and rather complemented each other. The clone library was dominated by sequences related to the Desulfobacteraceae, while only one isolate belonged to this family. Most of the strains were affiliated to the genera Desulfopila and Desulfotalea within the Desulfobulbaceae. Desulfopila-related strains exhibited a high phylogenetic microdiversity and represented numerically significant populations. In contrast, Desulfovibrio isolates were less abundant but displayed a high phylogenetic diversity. Three hundred and eighty-four-well microplate isolations enhanced significantly the number of isolates handled. As a consequence, 15 new taxa sharing less than 98% sequence similarity (16S rRNA gene) with their closest relatives were obtained. This polyphasic approach allowed to obtain a high phylogenetic diversity and thus a better view of sulfate-reducing communities in intertidal sediments. PMID:22809466

  19. 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 ...

  20. Composition and dynamics of sulfate-reducing bacteria during the waterflooding process in the oil field application.

    PubMed

    Wei, Li; Ma, Fang; Zhao, Guang

    2010-04-01

    The composition and dynamics of sulfate-reducing bacteria (SRB) during the waterflooding process of Daqing Oilfield were investigated in this study. PCR-DGGE analysis indicated that the microbial communities were significantly different in each treatment unit, and the dominant members were mainly close to Clostridium sp., Thauera sp., Hydrogenophaga sp., Pseudomonas sp., Eubacterium sp. and Arcobacter sp. However, the members belonging to SRB were relatively few and mainly consisted of Desulfovibrio sp. and Desulfovibrio profundus. According to APS (adenosine-5'-phosphosulfate reductase) gene clone library and sequence analysis, it was found that SRB mainly belonged to Proteobacteria and Deltaproteobacteria. In the library, the genus Desulfovibrio of Deltaproteobacteria was about 65.2% while genus Desulfomonas, Desulfomicrobium, Desulfohalobium, Desulfonatronum, Desulfbulbus, Desulforhopalus, Desulfnema and Desulforhopalus were occupied nearly 34.8%. It was also proved that most of SRB in the oil field were enriched in the ground treatment unit and they are not in the liquid of oil well. PMID:20005702

  1. 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

  2. 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

  3. 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).

  4. 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 acidic conditions. The dsrAB genes are related to other novel SRB lineages derived from acidic environments in previous reports, suggesting that these species have adapted to the acidity rather than colonized more circumneutral microenvironments. In an acidic hypersaline lake system in NW Victoria (Australia), previous studies suggested that pore water bisulfide derived from anoxic groundwater transported from distal locations. However, isolated potholes of oxic Fe(III)-rich springwater exhibited nearly a two-fold increase in conductivity and pH increase from 4.5 to 8.0 over time periods on the order of days; and biogeochemical and mineralogical observations were consistent with the presence of active acid- and halo-tolerant SRB. Furthermore, stratified active microbial mat communities, with zones of black FeS formation localized several millimeters below the sediment-air interface, were identified in cross-section from lakeshore sediments near groundwater discharge springs. Culture-independent and culture-based work to characterize the SRB population is ongoing at this site. We infer, from previous sulfur isotope tracer experiments at the lake, that overall sulfate reduction rates may be slow, but are nonetheless proceeding and contributing to the recycling of oxidized iron to a significant degree given the abundance of sulfate evidenced by widespread gypsum precipitation. We conclude from the two study-sites described above that acid-tolerant SRB species play an important role in the linked S, Fe and C cycles in acidifying, iron-rich environments, and their phylogenetic and physiological diversity should be further investigated.

  5. 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

  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 iron was poorly crystalline. At UM, laboratory-scale reactor studies were performed to assess the potential for the predominant abiotic reductants formed under sulfate reducing conditions (SRCs) to: (1) reduce U(VI) in contaminated groundwater sediments), and (2) inhibit the re-oxidation of U(IV) species, and in particular, uraninite (UO2(s)). Under SRCs, mackinawite and aqueous sulfide are the key reductants expected to form. To assess their potential for abiotic reduction of U(VI) species, a series of experiments were performed in which either FeS or S(-II) was added to solutions of U(VI), with the rates of conversion to U(IV) solids monitored as a function of pH, and carbonate and calcium concentration. In the presence of FeS and absence of oxygen or carbonate, U(IV) was completely reduced uraninite. S(-II) was also found to be an effective reductant of aqueous phase U(VI) species and produced uraninite, with the kinetics and extent of reduction depending on geochemical conditions. U(VI) reduction to uraninite was faster under higher S(-II) concentrations but was slowed by an increase in the dissolved Ca or carbonate concentration. Rapid reduction of U(VI) occurred at circumneutral pH but virtually no reduction occurred at pH 10.7. In general, dissolved Ca and carbonate slowed abiotic U(VI) reduction by forming stable Ca-U(VI)-carbonate soluble complexes that are resistant to reaction with aqueous sulfide. To investigate the stability of U(IV) against re-oxidation in the presence of iron sulfides by oxidants in simulated groundwater environments, and to develop a mechanistic understanding the controlling redox processes, continuously-mixed batch reactor (CMBR) and flow-through reactor (CMFR) studies were performed at UM. In these studies a series of experiments were conducted under various oxic groundwater conditions to examine the effectiveness of FeS as an oxygen scavenger to retard UO2 dissolution. The results indicate that FeS is an effective oxygen scavenger, and can lower the rate of oxidative dissolution of UO2 by over an order of magnitude compared to the absence of FeS, depending on pH, FeS content, and DO concentrations. Column reactor studies were performed at UM to assess the impact of mackinawite on uraninite oxidation under hydrodynamic flow conditions more representative of packed porous media at contaminated groundwater sites. In these studies, Rifle sediments were packed in the two columns which were subjected to different bioreduction steps and then run in parallel. The first column was bioreduced under SRCs (i.e., with sulfate in the influent) to generate mackinawite, mixed with uraninite, gamma-sterilized to inhibit subsequent microbiological activity, and then subjected to groundwater influent containing first nitrite and then oxygen. The second column was bioreduced (but in absence of sulfate in the influent) so that no iron sulfides would form, and then subjected to identical steps and influent as the first column. When nitrite was introduced in the influent of both columns, no significant release of U(VI) relative to the anoxic flow prior to nitrite addition occurred. However, when oxygen was introduced, the column which had undergone sulfate reduction (and had produced mackinawite as later verified by XAS) significantly lowered the peak U(VI) effluent concentrations, and in general, slowed U(VI) release considerably compared to the column with no FeS. Overall, these studies demonstrated that the presence of mackinawite can be a significant scavenger of oxygen and inhibit the oxidation of uraninite by oxygen, whereas nitrite had little impact on uraninite oxidation either in the presence or absence of FeS.

  7. 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

  8. 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.

  9. 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

  10. 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

  11. 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

  12. 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.

  13. 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...

  14. 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...

  15. 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...

  16. 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,...

  17. Draft Genome Sequence of Desulfocarbo indianensis SCBM, a New Genus of Sulfate-Reducing Bacteria, Isolated from Water Extracted from an Active Coalbed Methane Gas Well

    PubMed Central

    An, Thuy T.

    2015-01-01

    We used Illumina MiSeq technology to sequence the whole genome of Desulfocarbo indianensis SCBM, a new genus of sulfate-reducing bacteria isolated from a coal bed in Indiana, USA. This draft genome represents the first sequenced genome of the genus Desulfocarbo and the second known genome of the order Desulfarculales. PMID:26337881

  18. [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

  19. [Primary study on contents of sulfate reducing bacteria (SRB) and organic matter from intertidal zone at Chongming Dongtan].

    PubMed

    Yuan, Qi; Cui, Yu-Xue; Chen, Qing-Qiang; Lü, Bao-Yi; Xie, Bing

    2010-09-01

    Collected soil samples from different tidal flats and elevation in Chongming Dongtan wetland, then conducted sulfate-reducing bacteria (SRB) based on MPN method, determined organic matter content and calculated SO4(2-)/Cl- molar ratio, for the research on the distribution of SRB, relevance to soil organic matter content as well as influence of plant rhizosphere environment on SRB growth. The results show the distribution of SRB is ranked as middle flat > climax flat > bald flat. The same tidal flats at different depths, the SRB levels are shown as 51-52 cm > 21-22 cm > 81-82 cm, therefore 51-52 cm soil depth of Dongtan wetland is the suitable area for SRB to grow. However, in different tidal and depth, the distribution of organic matter content presents climax flat > middle flat > bald flat. From 21-51 cm, as the depth increasing, the organic matter content decreases while the amount of SRB significantly increasing, which indicates SRB utilizes the soil organic matter to carry out reduction reaction. The SO4(2-)/Cl- molar ratios of all soil samples are less than 0.05, indicating that SRB are actively engaged in sulfate reduction. The concentration of SRB in reed rhizosphere soil is the highest, showing that Phragmites australis rhizosphere environment in Dongtan wetland could enhance SRB growth, while the number of SRB in Spartina alterniflora rhizosphere environment is relatively lower than the non-rhizosphere environment, indicating that the rhizosphere effect has different effects on SRB in Dongtan tidal flats. PMID:21072939

  20. Enzymatic Recovery of Elemental Palladium by Using Sulfate-Reducing Bacteria

    PubMed Central

    Lloyd, Jon R.; Yong, Ping; Macaskie, Lynne E.

    1998-01-01

    Worldwide usage of platinum group metals is increasing, prompting new recovery technologies. Resting cells of Desulfovibrio desulfuricans reduced soluble Pd2+ to elemental, cell-bound Pd0 supported by pyruvate, formate, or H2 as the electron donor without biochemical cofactors. Pd reduction was O2 insensitive, opening the way for recycling and recovery of Pd under oxic conditions. PMID:9797331

  1. 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

  2. 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.

  3. 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

  4. Influence of sulfate-reducing bacteria on the passive film formed on austenitic stainless steel AISI 304

    SciTech Connect

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

    1995-03-01

    The influence of sulfate-reducing bacteria (SRB) on the passivity of a stainless steel, AISI 304, was investigated with X-ray photoelectron spectroscopy (XPS) and electrochemical techniques. Samples were exposed to SRB in growth media for 5 days. Potentiodynamic polarization tests were then conducted in deaerated 0.1 M HCl to determine if prior exposure to SRB compromised the passivity of the steel. The surface chemistry was analyzed with XPS, immediately after the exposure and following subsequent anodic polarization in 0.1 M HCl. Excess biomass generated by SRB could be rinsed from the steel with deaerated deionized water. Therefore, electrochemical and surface analysis were performed on both rinsed and unrinsed samples. Comparisons were made with control samples which were immersed in uninoculated media. The status of a newly polished sample at each stage of the investigation was given as an basis for comparison. It was found that SRB caused a loss of passivity in the 0.1 M HCl solution, due to the formation of sulfides. The following sulfides were observed: FeS, FeS{sub 2}, NiS, Cr{sub 2}S{sub 3} and possibly Fe{sub 1{minus}x}S{sub x}. The sulfides developed into the sublayer of the substrate during exposure to SRB and remained to hinder repassivation in the test electrolyte.

  5. Influence of sulfate-reducing bacteria on the passive film formed on austenitic stainless steel AISI 304

    SciTech Connect

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

    1995-10-01

    The influence of sulfate-reducing bacteria (SRB) on the passivity of a stainless steel, AISI 304, was investigated with X-ray photoelectron spectroscopy (XPS) and electrochemical techniques. Samples were exposed to SRB in growth media for 5 days. Potentiodynamic polarization tests were then conducted in deaerated 0.1 M HCl to determine if prior exposure to SRB compromised the passivity of the steel. The surface chemistry was analyzed with XPS, immediately after the exposure and following subsequent anodic polarization in 0.1 M HCl. Excess biomass generated by SRB could be rinsed from the steel with deaerated deionized water. Therefore, electrochemical and surface analysis were performed on both rinsed and unrinsed samples. Comparisons were made with control samples which were immersed in uninoculated media. The status of a newly polished sample at each stage of the investigation was given as a basis for comparison. It was found that SRB caused a loss of passivity in the 0.1 M HCl solution, due to the formation of sulfides. The following sulfides were observed: FeS, FeS{sub 2}, NiS, Cr{sub 2}S{sub 3} and possibly Fe{sub 1{minus}x}S{sub x}. The sulfides developed into the sublayer of the substrate during exposure to SRB and remained to hinder repassivation in the test electrolyte.

  6. 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 identified as Desulfovibrio indonesiensis, and strain B2T as Desulfotomaculum geothermicum. The other Desulfovibrio strains (H1M, H1-13, and B1T) showed identical 16S rDNA sequences and similarities as low as 93% to their closest relative, Desulfovibrio aminophilusT. Therefore, these isolates were assigned to a new species, Desulfovibrio cavernae sp. nov., with strain H1M as the type strain. PMID:15490555

  7. Community Structure, Cellular rRNA Content, and Activity of Sulfate-Reducing Bacteria in Marine Arctic Sediments

    PubMed Central

    Ravenschlag, Katrin; Sahm, Kerstin; Knoblauch, Christian; Jørgensen, Bo B.; Amann, Rudolf

    2000-01-01

    The community structure of sulfate-reducing bacteria (SRB) of a marine Arctic sediment (Smeerenburgfjorden, Svalbard) was characterized by both fluorescence in situ hybridization (FISH) and rRNA slot blot hybridization by using group- and genus-specific 16S rRNA-targeted oligonucleotide probes. The SRB community was dominated by members of the Desulfosarcina-Desulfococcus group. This group accounted for up to 73% of the SRB detected and up to 70% of the SRB rRNA detected. The predominance was shown to be a common feature for different stations along the coast of Svalbard. In a top-to-bottom approach we aimed to further resolve the composition of this large group of SRB by using probes for cultivated genera. While this approach failed, directed cloning of probe-targeted genes encoding 16S rRNA was successful and resulted in sequences which were all affiliated with the Desulfosarcina-Desulfococcus group. A group of clone sequences (group SVAL1) most closely related to Desulfosarcina variabilis (91.2% sequence similarity) was dominant and was shown to be most abundant in situ, accounting for up to 54.8% of the total SRB detected. A comparison of the two methods used for quantification showed that FISH and rRNA slot blot hybridization gave comparable results. Furthermore, a combination of the two methods allowed us to calculate specific cellular rRNA contents with respect to localization in the sediment profile. The rRNA contents of Desulfosarcina-Desulfococcus cells were highest in the first 5 mm of the sediment (0.9 and 1.4 fg, respectively) and decreased steeply with depth, indicating that maximal metabolic activity occurred close to the surface. Based on SRB cell numbers, cellular sulfate reduction rates were calculated. The rates were highest in the surface layer (0.14 fmol cell−1 day−1), decreased by a factor of 3 within the first 2 cm, and were relatively constant in deeper layers. PMID:10919825

  8. 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 chemical biocides or surface coating agents currently used to prevent SRB growth in petroleum industries. PMID:23131170

  9. Molecular Scale Dissolved Organic Matter Interactions Impact Mercury Bioavailability for Uptake and Methylation by Sulfate-Reducing Bacteria

    NASA Astrophysics Data System (ADS)

    Moreau, J. W.; Krabbenhoft, D. P.

    2008-12-01

    Biogeochemical factors such as dissolved natural organic matter (DOM) type and abundance may play a major role in governing the bioavailability of aqueous Hg(II) for uptake and methylation by sulfate-reducing bacteria (SRB). MeHg production correlates in some cases with predicted dominance of hydrophobic, neutrally-charged, aqueous HgS. This species is thought to interact strongly with DOM via hydrophobic attractions. Field and laboratory observations suggest that DOM promotes methylation. We therefore hypothesized that DOM isolates of differing (well-characterized) functional compositions (e.g., hydrophobic versus hydrophilic) could variably enhance bacterial methylation. Methylation assays using Desulfobulbus propionicus 1pr3 in fermentative growth were performed using a mercury isotope tracer applied at concentrations of roughly 100 ng/L. The tracer was pre-equilibrated with 5-10 uM aqueous sulfide and approximately 40 mg/L of either hydrophobic or hydrophilic DOM prior to inoculation. Results showed roughly 1-3% tracer methylation in both hydrophobic DOM+ and DOM- cultures. However, a similar amount of non- tracer (background) mercury associated with the hydrophobic DOM fraction was also methylated. Preliminary results suggested that pre-equilibration of the isotope tracer for up to one month with hydrophobic-fraction humic acids resulted in a roughly 2-3X increase in the quantity and rate of methylation, indicating an important role for aging on DOM in Hg bioavailability. Mercury-sulfide-DOM equilibration products were investigated with synchrotron-based x-ray fluorescence spectroscopy (EXAFS) at liquid nitrogen temperatures. Hg L(III)-edge spectra from resin-concentrated Hg-S-DOM equilibration products exhibited high similarity to a metacinnabar-like conformation. Culturing and EXAFS results, taken together, suggest that nanophase metacinnabar, "packaged" in DOM, could have been the bioavailable form of Hg(II) in culturing experiments. Further experiments involving other DOM fractions, and new EXAFS investigations are ongoing, to explore further the mechanism of bacterial mercury methylation.

  10. Application of denaturing high-performance liquid chromatography for monitoring sulfate-reducing bacteria in oil fields.

    PubMed

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

    2013-09-01

    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 × 10(1) to 6 × 10(5) 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

  11. Inside the alkalinity engine: the role of electron donors in the organomineralization potential of sulfate-reducing bacteria.

    PubMed

    Gallagher, K L; Kading, T J; Braissant, O; Dupraz, C; Visscher, P T

    2012-11-01

    Mineral precipitation in microbial mats may have been the key to their preservation as fossil stromatolites, potentially documenting evidence of the earliest life on Earth. Two factors that contribute to carbonate mineral precipitation are the saturation index (SI) and the presence of nucleation sites. Both of these can be influenced by micro-organisms, which can either alter SI through their metabolisms, or produce and consume organic substances such as extracellular polymeric substances (EPS) that can affect nucleation. It is the balance of individual metabolisms within the mat community that determines the pH and the dissolved inorganic carbon concentration, thereby potentially increasing the alkalinity and consequently the SI. Sulfate-reducing bacteria (SRB) are an important component of this 'alkalinity engine.' The activity of SRB often peaks in layers where CaCO(3) precipitates, and mineral precipitation has been demonstrated in SRB cultures; however, the effect of their metabolism on the alkalinity engine and actual contribution to mineral precipitation is the subject of controversy. Here, we show through culture experiments, theoretical calculations, and geochemical modeling studies that the pH, alkalinity, and organomineralization potential will vary depending on the type of electron donor. Specifically, hydrogen and formate can increase the pH, but electron donors like lactate and ethanol, and to a lesser extent glycolate, decrease the pH. The implication of this for the lithification of mats is that the combination of processes supplying electron donors and the utilization of these compounds by SRB may be critical to promoting mineral precipitation. PMID:22925453

  12. 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

  13. 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.

  14. 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.

  15. Anaerobic degradation of alkylbenzenes in crude oil. II. Changes of oil composition upon incubation with sulfate-reducing and denitrifying bacteria

    SciTech Connect

    Wilkes, H.; Willsch, H.; Rabus, R.; Aeckersberg, F.

    1996-10-01

    Various alkylbenzenes in crude oils are degradable by several newly isolated sulfate-reducing and nitrate-reducing bacteria under strictly anoxic conditions. A mesophilic enrichment culture consisting of at least two different types of sulfate-reducing bacteria, depletes toluene, o- and m-xylene, o- and m-ethyltoluene, m-propyltoluene and m-cymene in crude oils at different rates. Experiments with different oils reveal that in general the degradation efficiency seems to depend not very strongly on the composition of the incubated oils. Results of our experiments with nitrate-reducing bacteria show that at least toluene, ethyltoluene and m-, p- and o-xylene in crude oils are biodegradable under denitrifying conditions. All organisms isolated so far exhibit a high substrate specifity. Up to now no indications for the alteration of other oil fractions, i.e. n-alkanes, biomarkers and PAH`s, could be observed with any of the bacteria used in this study. The possible role of alkylbenzene-degrading anaerobic bacteria in biodegradation of petroleums in natural environments will be discussed.

  16. 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).

  17. 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.

  18. 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. alterniflora invasion. Approximately 11.3 ± 5.1% of the dsrB gene sequences formed a novel cluster that was reduced upon the invasion. The results showed that in the sediments of tidal salt marsh where S. alterniflora displaced P. australis, the abundances of methanogens and SRB increased, but the community composition of methanogens appeared to be influenced more than did the SRB. PMID:23986751

  19. Diversity of methanogens and sulfate-reducing bacteria in the interfaces of five deep-sea anoxic brines of the Red Sea.

    PubMed

    Guan, Yue; Hikmawan, Tyas; Antunes, André; Ngugi, David; Stingl, Ulrich

    2015-11-01

    Oceanic deep hypersaline anoxic basins (DHABs) are characterized by drastic changes in physico-chemical conditions in the transition from overlaying seawater to brine body. Brine-seawater interfaces (BSIs) of several DHABs across the Mediterranean Sea have been shown to possess methanogenic and sulfate-reducing activities, yet no systematic studies have been conducted to address the potential functional diversity of methanogenic and sulfate-reducing communities in the Red Sea DHABs. Here, we evaluated the relative abundance of Bacteria and Archaea using quantitative PCR and conducted phylogenetic analyses of nearly full-length 16S rRNA genes as well as functional marker genes encoding the alpha subunits of methyl-coenzyme M reductase (mcrA) and dissimilatory sulfite reductase (dsrA). Bacteria predominated over Archaea in most locations, the majority of which were affiliated with Deltaproteobacteria, while Thaumarchaeota were the most prevalent Archaea in all sampled locations. The upper convective layers of Atlantis II Deep, which bear increasingly harsh environmental conditions, were dominated by members of the class Thermoplasmata (Marine Benthic Group E and Mediterranean Sea Brine Lakes Group 1). Our study revealed unique microbial compositions, the presence of niche-specific groups, and collectively, a higher diversity of sulfate-reducing communities compared to methanogenic communities in all five studied locations. PMID:26192212

  20. 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 (?13C = -48 to -70) in the hydrate-bearing samples, suggesting that they are involved in the oxidation of methane (?13C = -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 ?13C values (to -11.2). In the hydrate-free sample, fatty acid biomarkers have ?13C 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.

  1. Quantification of Tinto River sediment microbial communities: importance of sulfate-reducing bacteria and their role in attenuating acid mine drainage.

    PubMed

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

    2012-07-01

    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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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.

  7. Molecular analysis of deep subsurface Cretaceous rock indicates abundant Fe(III)- and S°-reducing bacteria in a sulfate-rich environment

    SciTech Connect

    Kovacik, William P.; Takai, Ken; Mormile, Melanie R.; McKinley, James P.; Brockman, Fred J.; Fredrickson, Jim K.; Holben, William E.

    2006-01-01

    A multi-level sampler (MLS) was emplaced in a borehole straddling anaerobic, sulfate-rich Cretaceous-era shale and sandstone rock formations {approx}200 m below ground surface at Cerro Negro, New Mexico. Sterile quartzite sand contained in chambers in the sampler allowed in situ colonization and recovery of nucleic acids for molecular analyses. DGGE and 16S rRNA gene cloning results indicated a homogeneously distributed bacterial community across the shale/sandstone interface. ?-Proteobacteria sequences were common at all depths, and were dominated by members of the Geobacteraceae family (Pelobacter, Desulfuromonas, and Geobacter). Other members of this group are capable of dissimilatory Fe(III) and/or S0 reduction, but not sulfate reduction. RNA hybridization data also suggested that Fe(III)/S0 reducing bacteria were predominant. These findings are striking considering the lack of significant concentrations of these electron acceptors in this environment. The next most abundant bacterial group indicated was the sulfate reducers, including Desulfobacterium, Desulfocapsa and Desulfobulbus. Sequences related to fermenters, denitrifiers and acetogens were also recovered. The presence of a phylogenetically and functionally diverse microbial community in this deep subsurface environment likely reflects the complex nature of the primary energy and carbon sources, kerogen associated with the shale.

  8. Molecular analysis of deep subsurface Cretaceous rock indicates abundant Fe(III)- and S(zero)-reducing bacteria in a sulfate-rich environment.

    PubMed

    Kovacik, William P; Takai, Ken; Mormile, Melanie R; McKinley, James P; Brockman, Fred J; Fredrickson, James K; Holben, William E

    2006-01-01

    A multilevel sampler (MLS) was emplaced in a borehole straddling anaerobic, sulfate-rich Cretaceous-era shale and sandstone rock formations approximately 200 m below ground surface at Cerro Negro, New Mexico. Sterile quartzite sand contained in chambers in the sampler allowed in situ colonization and recovery of nucleic acids for molecular analyses. Denaturing gradient gel electrophoresis and 16S rRNA gene cloning results indicated a homogeneously distributed bacterial community across the shale-sandstone interface. delta-Proteobacteria sequences were common at all depths, and were dominated by members of the Geobacteraceae family (Pelobacter, Desulphuromonas and Geobacter). Other members of this group are capable of dissimilatory Fe(III) and/or S degrees reduction, but not sulfate reduction. RNA hybridization data also suggested that Fe(III)-/S degrees -reducing bacteria were predominant. These findings are striking considering the lack of significant concentrations of these electron acceptors in this environment. The next most abundant bacterial group indicated was the sulfate reducers, including Desulfobacterium, Desulfocapsa and Desulfobulbus. Sequences related to fermenters, denitrifiers and acetogens were also recovered. The presence of a phylogenetically and functionally diverse microbial community in this deep subsurface environment likely reflects the complex nature of the primary energy and carbon sources, kerogen associated with the shale. PMID:16343329

  9. 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

  10. 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

  11. 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

  12. 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

  13. 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

  14. 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

  15. Optimization of sulfide production by an indigenous consortium of sulfate-reducing bacteria for the treatment of lead-contaminated wastewater.

    PubMed

    Kieu, Thi Quynh Hoa; Nguyen, Thi Yen; Dang, Thi Yen; Nguyen, Thanh Binh; Vuong, Thi Nga; Horn, Harald

    2015-10-01

    Biological treatment with sulfate-reducing bacteria (SRB) is considered to be an excellent option to remove heavy metals from wastewater. In this study, the optimization of sulfide production for an enhanced removal of lead by a consortium of SRB was carried out based on central composite design and analyzed using response surface methodology (RSM). The sulfide production process was investigated as a function of three independent variables: solution pH (6.5-8.5), lactate concentration (32-96 mM), and sulfate concentration (16-32 mM). RSM analysis showed that the optimum conditions for a high sulfide concentration (14.2 mM) occurred at a pH of 7.5 and at lactate and sulfate concentrations of 53.4 mM and 22.6 mM, respectively. The lead removal efficiency of the SRB consortium using optimum conditions was determined in four parallel anaerobic continuous moving bed biofilm reactors (V = 2 L) that were fed with synthetic wastewater containing dissolved lead at concentrations of 0, 100, 150, 200 mg L(-1) and operated with a hydraulic retention time of 5 days. 99-100 % was removed from synthetic wastewater with lead concentrations of 100 and 150 mg L(-1) during 40 days of operation. For the highest lead concentration of 200 mg L(-1), a decrease in efficiency of removal (96 %) was observed at the end of the experiment. PMID:26251206

  16. 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

  17. Sulfate-reducing bacteria-dominated biofilms that precipitate ZnS in a subsurface circumneutral-pH mine drainage system.

    PubMed

    Labrenz, M; Banfield, J F

    2004-04-01

    The microbial diversity of ZnS-forming biofilms in 8 degrees C, circumneutral-pH groundwater in tunnels within the abandoned Piquette Zn, Pb mine (Tennyson, Wisconsin, USA) has been investigated by molecular methods, fluorescence in situ hybridization (FISH), and cultivation techniques. These biofilms are growing on old mine timbers that generate locally anaerobic zones within the mine drainage system. Sulfate-reducing bacteria (SRB) exclusively of the family Desulfobacteriaceae comprise a significant fraction of the active microbiota. Desulfosporosinus strains were isolated, but could not be detected by molecular methods. Other important microbial clusters belonged to the beta-, gamma-, and epsilon-Proteobacteria, the Cytophaga/Flexibacter/Bacteroides-group (CFB), Planctomycetales, Spirochaetales, Clostridia, and green nonsulfur bacteria. Our investigations indicated a growth dependence of SRB on fermentative, cellulolytic, and organic acid-producing Clostridia. A few clones related to sulfur-oxidizing bacteria were detected, suggesting a sulfur cycle related to redox gradients within the biofilm. Sulfur oxidation prevents sulfide accumulation that would lead to precipitation of other sulfide phases. FISH analyses indicated that Desulfobacteriaceae populations were not early colonizers in freshly grown and ZnS-poor biofilms, whereas they were abundant in older, naturally established, and ZnS-rich biofilms. Gram-negative SRB have been detected in situ over a period of 6 months, supporting the important role of these organisms in selective ZnS precipitation in Tennyson mine. Results demonstrate the complex nature of biofilms responsible for in situ bioremediation of toxic metals in a subsurface mine drainage system. PMID:14994175

  18. 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-grained black muds that are distinguishable from coarser pyrite cinders, and exhibit a noticeably strong sulfide odor. Aero- and halo-tolerant SRB were enriched from circumneutral pH cores, and we hypothesize that acido-tolerant SRB may also be present. Analysis of restriction fragment length polymorphism of whole community 16S rDNA extracted from each core shows an expected increase in diversity between acidic and circumneutal sediments, and clone libraries from both contaminated and uncontaminated marsh sediments are being compared to assess the impact of long-term contamination. References: Webb et al. 1998, J. Appl. Microbio., 84, 240-248; Moreau et al. 2003, Amer. Min., in review; URS Corp. 2001, Report 51.09967067.00.

  19. 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

  20. 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

  1. 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

  2. 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-occurrences containing putatively heterotrophic, candidate phyla such as OD1, Atribacteria, MBG-B, and Hyd24-12 and the potential for complex sulfur cycling involving Epsilon-, Delta-, and Gammaproteobacteria in methane seep ecosystems. PMID:27114874

  3. 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-occurrences containing putatively heterotrophic, candidate phyla such as OD1, Atribacteria, MBG-B, and Hyd24-12 and the potential for complex sulfur cycling involving Epsilon-, Delta-, and Gammaproteobacteria in methane seep ecosystems. PMID:27114874

  4. 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

  5. Phylogeography of Sulfate-Reducing Bacteria among Disturbed Sediments, Disclosed by Analysis of the Dissimilatory Sulfite Reductase Genes (dsrAB)

    PubMed Central

    Pérez-Jiménez, J. R.; Kerkhof, L. J.

    2005-01-01

    Sediment samples were collected worldwide from 16 locations on four continents (in New York, California, New Jersey, Virginia, Puerto Rico, Venezuela, Italy, Latvia, and South Korea) to assess the extent of the diversity and the distribution patterns of sulfate-reducing bacteria (SRB) in contaminated sediments. The SRB communities were examined by terminal restriction fragment (TRF) length polymorphism (TRFLP) analysis of the dissimilatory sulfite reductase genes (dsrAB) with NdeII digests. The fingerprints of dsrAB genes contained a total of 369 fluorescent TRFs, of which <20% were present in the GenBank database. The global sulfidogenic communities appeared to be significantly different among the anthropogenically impacted (petroleum-contaminated) sites, but nearly all were less diverse than pristine habitats, such as mangroves. A global SRB indicator species of petroleum pollution was not identified. However, several dsrAB gene sequences corresponding to hydrocarbon-degrading isolates or consortium members were detected in geographically widely separated polluted sites. Finally, a cluster analysis of the TRFLP fingerprints indicated that many SRB microbial communities were most similar on the basis of close geographic proximity (tens of kilometers). Yet, on larger scales (hundreds to thousands of kilometers) SRB communities could cluster with geographically widely separated sites and not necessarily with the site with the closest proximity. These data demonstrate that SRB populations do not adhere to a biogeographic distribution pattern similar to that of larger eukaryotic organisms, with the greatest species diversity radiating from the Indo-Pacific region. Rather, a patchy SRB distribution is encountered, implying an initially uniform SRB community that has differentiated over time. PMID:15691959

  6. Methane production correlates positively with methanogens, sulfate-reducing bacteria and pore water acetate at an estuarine brackish-marsh landscape scale

    NASA Astrophysics Data System (ADS)

    Tong, C.; She, C. X.; Jin, Y. F.; Yang, P.; Huang, J. F.

    2013-11-01

    Methane production is influenced by the abundance of methanogens and the availability of terminal substrates. Sulfate-reducing bacteria (SRB) also play an important role in the anaerobic decomposition of organic matter. However, the relationships between methane production and methanogen populations, pore water terminal substrates in estuarine brackish marshes are poorly characterized, and even to our knowledge, no published research has explored the relationship between methane production rate and abundance of SRB and pore water dimethyl sulfide (DMS) concentration. We investigated methane production rate, abundances of methanogens and SRB, concentrations of pore water terminal substrates and electron acceptors at a brackish marsh landscape dominated by Phragmites australis, Cyperus malaccensis and Spatina alterniflora marshes zones in the Min River estuary. The average rates of methane production at a soil depth of 30 cm in the three marsh zones were 0.142, 0.058 and 0.067 ?g g-1 d-1, respectively. The abundance of both methanogens and SRB in the soil of the P. australis marsh with highest soil organic carbon content was higher than in the C. malaccensis and S. alterniflora marshes. The abundance of methanogens and SRB in the three soil layers was statistically indistinguishable. Mean pore water DMS concentrations at a soil depth of 30 cm under the S. alterniflora marsh were higher than those in the C. malaccensis and P. australis marshes. Methane production rate increased with the abundance of both methanogens and SRB across three marsh zones together at the landscape scale, and also increased with the concentration of pore water acetate, but did not correlate with concentrations of pore water DMS and dissolved CO2. Our results suggest that, provided that substrates are available in ample supply, methanogens can continue to produce methane regardless of whether SRB are prevalent in estuarine brackish marshes.

  7. Distribution of sulfate-reducing bacteria in a stratified fjord (Mariager Fjord, Denmark) as evaluated by most-probable-number counts and denaturing gradient gel electrophoresis of PCR-amplified ribosomal DNA fragments.

    PubMed Central

    Teske, A; Wawer, C; Muyzer, G; Ramsing, N B

    1996-01-01

    The sulfate-reducing bacterial populations of a stratified marine water column, Mariager Fjord, Denmark, were investigated by molecular and culture-dependent approaches in parallel. Denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA and DNA encoding rRNA (rDNA) isolated from the water column indicated specific bacterial populations in different water column layers and revealed a highly differentiated pattern of rRNA- and rDNA-derived PCR amplificates, probably reflecting active and resting bacterial populations. Hybridization of DGGE patterns with rRNA probes indicated the increased presence and activity (by at least 1 order of magnitude) of sulfate-reducing bacteria within and below the chemocline. Parallel to this molecular approach, an approach involving most-probable-number (MPN) counts was used, and it found a similar distribution of cultivable sulfate-reducing bacteria in the water column of Mariager Fjord, Approximately 25 cells and 250 cells per ml above and below the chemocline, respectively, were found. Desulfovibrio- and Desulfobulbus-related strains occurred in the oxic zone. DGGE bands from MPN cultures were sequenced and compared with those obtained from nucleic acids extracted from water column samples. The MPN isolates were phylogenetically affiliated with sulfate-reducing delta subdivision proteobacteria (members of the genera Desulfovibrio, Desulfobulbus, and Desulfobacter), whereas the molecular isolates constituted an independent lineage of the delta subdivision proteobacteria. DGGE of PCR-amplified nucleic acids with general eubacterial PCR primers conceptually revealed the general bacterial population, whereas the use of culture media allowed cultivable sulfate-reducing bacteria to be selected. A parallel study of Mariager Fjord biogeochemistry, bacterial activity, and bacterial counts complementing this investigation has been presented elsewhere (N.B. Ramsing, H. Fossing, T. G. Ferdelman, F. Andersen, and B. Thamdrup, Appl. Environ. PMID:8919802

  8. Polyhydroxyalkanoate (PHA) Accumulation in Sulfate-Reducing Bacteria and Identification of a Class III PHA Synthase (PhaEC) in Desulfococcus multivorans

    PubMed Central

    Hai, Tran; Lange, Daniela; Rabus, Ralf; Steinbüchel, Alexander

    2004-01-01

    Seven strains of sulfate-reducing bacteria (SRB) were tested for the accumulation of polyhydroxyalkanoates (PHAs). During growth with benzoate Desulfonema magnum accumulated large amounts of poly(3-hydroxybutyrate) [poly(3HB)]. Desulfosarcina variabilis (during growth with benzoate), Desulfobotulus sapovorans (during growth with caproate), and Desulfobacterium autotrophicum (during growth with caproate) accumulated poly(3HB) that accounted for 20 to 43% of cell dry matter. Desulfobotulus sapovorans and Desulfobacterium autotrophicum also synthesized copolyesters consisting of 3-hydroxybutyrate and 3-hydroxyvalerate when valerate was used as the growth substrate. Desulfovibrio vulgaris and Desulfotalea psychrophila were the only SRB tested in which PHAs were not detected. When total DNA isolated from Desulfococcus multivorans and specific primers deduced from highly conserved regions of known PHA synthases (PhaC) were used, a PCR product homologous to the central region of class III PHA synthases was obtained. The complete pha locus of Desulfococcus multivorans was subsequently obtained by inverse PCR, and it contained adjacent phaEDm and phaCDm genes. PhaCDm and PhaEDm were composed of 371 and 306 amino acid residues and showed up to 49 or 23% amino acid identity to the corresponding subunits of other class III PHA synthases. Constructs of phaCDm alone (pBBRMCS-2::phaCDm) and of phaEDmCDm (pBBRMCS-2::phaEDmCDm) in various vectors were obtained and transferred to several strains of Escherichia coli, as well as to the PHA-negative mutants PHB−4 and GPp104 of Ralstonia eutropha and Pseudomonas putida, respectively. In cells of the recombinant strains harboring phaEDmCDm small but significant amounts (up to 1.7% of cell dry matter) of poly(3HB) and of PHA synthase activity (up to 1.5 U/mg protein) were detected. This indicated that the cloned genes encode functionally active proteins. Hybrid synthases consisting of PhaCDm and PhaE of Thiococcus pfennigii or Synechocystis sp. strain PCC 6308 were also constructed and were shown to be functionally active. PMID:15294771

  9. Test-kits for thiosulfate-reducing bacteria

    SciTech Connect

    Crolet, J.L.; Magot, M.; Brazy, J.L.

    1997-08-01

    API or proprietary test-kits presently used for the detection of bacteria involved in microbial corrosion are designed for specific detection of sulfate-reducing bacteria (SRB). It was recently shown that other sulfidogenic bacteria such as thiosulfate-reducing bacteria (TRB) are also involved in the corrosion of carbon steel. Since these bacteria cannot be detected by SRB test-kits, a new kit was developed for TRB detection, and validated in field trials.

  10. 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...

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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

  16. Development of molecular monitoring methods for the evaluation of the activity of sulfate- and metal reducing bacteria (SMRBS) as an indication of the in situ immobilisation of heavy metals and metalloids.

    PubMed

    Geets, J; Vangronsveld, J; Borremans, B; Diels, L; van der Lelie, D

    2001-01-01

    Sulfate- and metal reducing bacteria (SMRBs) are known for their capacity to reduce and precipitate heavy metals and metalloids (HMM) as metalsulfides (Luptkov A et al, 1998), which have the characteristic of forming stable precipitates due to their very low solubility product. Therefore, we examined the potential of using the activity of SMRBs to create a bioreactive zone or barrier for the in situ precepitation of heavy metals as a remediation strategy for heavy metal contaminated groundwater. In order to obtain insight in the ongoing biological processes for using this information to direct or optimize the in situ HMM- precipitation process, a monitoring strategy for sulfate- reduction activity of SMRBs must be designed using molecular methods. Here, we report the results of batch and column experiments which demonstrate the feasibility to stimulate the endogenous SRB- population, resulting in the in situ precipitation of HMM as sulfide complexes. Moreover, the sustainability of the in situ HMM precipitation wa s shown. For the development of molecular monitoring methods, the community structures of different bacterial consortia, obtained from bioreactors, was analysed by shotgun cloning of total community DNA followed by sequencing of the 16S rRNA- gene. The SRB- specific 16S rRNA- primerset SRB385R- 907F was used but this specificity to specifically amplify the 16S rRNA- gene of SRBs was low. Also, the dsr (dissimilatory sulfite reductase)- gene specific DSR1F- DSR4R primerset showed sometimes after amplification of the dsr- genes as part of the community structure analysis satellite bands on agarose gel. Present work is concentrating on the isolation and identification of SRB- strains in the different bacterial cultures. Shotgun cloning of the 16S rRNA- and dsr- gene of the strains and total community DNA will give the information that is necessary for the optimization of existing SRB- specific primers and design of new primers. These primers will be used for the development of monitoring techniques. PMID:15954561

  17. 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.

  18. Uranium Immobilization by Sulfate-reducing Biofilms

    SciTech Connect

    Beyenal, Haluk; Sani, Rajesh K.; Peyton, Brent M.; Dohnalkova, Alice; Amonette, James E.; Lewandowski, Zbigniew

    2004-04-01

    Hexavalent uranium [U(VI)] was immobilized using biofilms of the sulfate-reducing bacterium (SRB) Desulfovibrio desulfuricans G20. The biofilms were grown in flat-plate continuous-flow reactors using lactate as the electron donor and sulfate as the electron acceptor. U(VI) was continuously fed into the reactor for 32 weeks at a concentration of 126 íM. During this time, the soluble U(VI) was removed (between 88 and 96% of feed) from solution and immobilized in the biofilms. The dynamics of U immobilization in the sulfate-reducing biofilms were quantified by estimating: (1) microbial activity in the SRB biofilm, defined as the hydrogen sulfide (H2S) production rate and estimated from the H2S concentration profiles measured using microelectrodes across the biofilms; (2) concentration of dissolved U in the solution; and (3) the mass of U precipitated in the biofilm. Results suggest that U was immobilized in the biofilms as a result of two processes: (1) enzymatically and (2) chemically, by reacting with microbially generated H2S. Visual inspection showed that the dissolved sulfide species reacted with U(VI) to produce a black precipitate. Synchrotron-based U L3-edge X-ray absorption near edge structure (XANES) spectroscopy analysis of U precipitated abiotically by sodium sulfide indicated that U(VI) had been reduced to U(IV). Selected-area electron diffraction pattern and crystallographic analysis of transmission electron microscope lattice-fringe images confirmed the structure of precipitated U as being that of uraninite.

  19. 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.

  20. Natural relationships among sulfate-reducing eubacteria.

    PubMed Central

    Devereux, R; Delaney, M; Widdel, F; Stahl, D A

    1989-01-01

    Phylogenetic relationships among 20 nonsporeforming and two endospore-forming species of sulfate-reducing eubacteria were inferred from comparative 16S rRNA sequencing. All genera of mesophilic sulfate-reducing eubacteria except the new genus Desulfomicrobium and the gliding Desulfonema species were included. The sporeforming species Desulfotomaculum ruminis and Desulfotomaculum orientis were found to be gram-positive organisms sharing 83% 16S rRNA sequence similarity, indicating that this genus is diverse. The gram-negative nonsporeforming species could be divided into seven natural groups: group 1, Desulfovibrio desulfuricans and other species of this genus that do not degrade fatty acids (this group also included "Desulfomonas" pigra); group 2, the fatty acid-degrading "Desulfovibrio" sapovorans; group 3, Desulfobulbus species; group 4, Desulfobacter species; group 5, Desulfobacterium species and "Desulfococcus" niacini; group 6, Desulfococcus multivorans and Desulfosarcina variabilis; and group 7, the fatty acid-oxidizing "Desulfovibrio" baarsii. (The quotation marks are used to indicate the need for taxonomic revision.) Groups 1 to 3 are incomplete oxidizers that form acetate as an end product; groups 4 to 7 are complete oxidizers. The data were consistent with and refined relationships previously inferred by oligonucleotide catalogs of 16S rRNA. Although the determined relationships are generally consistent with the existing classification based on physiology and other characteristics, the need for some taxonomic revision is indicated. PMID:2480344

  1. Treatment and electricity harvesting from sulfate/sulfide-containing wastewaters using microbial fuel cell with enriched sulfate-reducing mixed culture.

    PubMed

    Lee, Duu-Jong; Lee, Chin-Yu; Chang, Jo-Shu

    2012-12-01

    Anaerobic treatment of sulfate-laden wastewaters can produce excess sulfide, which is corrosive to pipelines and is toxic to incorporated microorganisms. This work started up microbial fuel cell (MFC) using enriched sulfate-reducing mixed culture as anodic biofilms and applied the so yielded MFC for treating sulfate or sulfide-laden wastewaters. The sulfate-reducing bacteria in anodic biofilm effectively reduced sulfate to sulfide, which was then used by neighboring anode respiring bacteria (ARB) as electron donor for electricity production. The presence of organic carbons enhanced MFC performance since the biofilm ARB were mixotrophs that need organic carbon to grow. The present device introduces a route for treating sulfate laden wastewaters with electricity harvesting. PMID:23116719

  2. 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.

  3. Structural and Functional Dynamics of Sulfate-Reducing Populations in Bacterial Biofilms

    PubMed Central

    Santegoeds, Cecilia M.; Ferdelman, Timothy G.; Muyzer, Gerard; de Beer, Dirk

    1998-01-01

    We 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 μm 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 (approximately 108 SRB/ml) 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. Our data indicate that not all SRB detected by molecular analysis were sulfidogenically active in the biofilm. PMID:9758792

  4. Electron transfer from sulfate-reducing becteria biofilm promoted by reduced graphene sheets

    NASA Astrophysics Data System (ADS)

    Wan, Yi; Zhang, Dun; Wang, Yi; Wu, Jiajia

    2012-01-01

    Reduced graphene sheets (RGSs) mediate electron transfer between sulfate-reducing bacteria (SRB) and solid electrodes, and promote the development of microbial fuel cells (MFC). We have investigated RSG-promoted electron transfer between SRB and a glassy carbon (GC) electrode. The RGSs were produced at high yield by a chemical sequence involving graphite oxidation, ultrasonic exfoliation of nanosheets, and N2H4 reduction. Cyclic voltammetric testing showed that the characteristic anodic peaks (around 0.3 V) might arise from the combination of bacterial membrane surface cytochrome c3 and the metabolic products of SRB. After 6 d, another anodic wave gradually increased to a maximum current peak and a third anodic signal became visible at around 0 V. The enhancements of two characteristic anodic peaks suggest that RSGs mediate electron-transfer kinetics between bacteria and the solid electrode. Manipulation of these recently-discovered electron-transport mechanisms will lead to significant advances in MFC engineering.

  5. 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

  6. 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

  7. 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

  8. 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

  9. 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 Fe?O? in a two - stage anaerobic reactor (A1, S1). The addition of Fe?O? 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 Fe?O? (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

  10. Mine wastewater treatment using Phalaris arundinacea plant material hydrolyzate as substrate for sulfate-reducing bioreactor.

    PubMed

    Lakaniemi, Aino-Maija; Nevatalo, Laura M; Kaksonen, Anna H; Puhakka, Jaakko A

    2010-06-01

    A low-cost substrate, Phalaris arundinacea was acid hydrolyzed (Reed Canary Grass hydrolyzate, RCGH) and used to support sulfate reduction. The experiments included batch bottle assays (35 degrees C) and a fluidized-bed bioreactor (FBR) experiment (35 degrees C) treating synthetic mine wastewater. Dry plant material was also tested as substrate in batch bottle assays. The batch assays showed sulfate reduction with the studied substrates, producing 540 and 350mgL(-1) dissolved sulfide with RCGH and dry plant material, respectively. The soluble sugars of the RCGH presumably fermented into volatile fatty acids and hydrogen, which served as electron donors for sulfate reducing bacteria. A sulfate reduction rate of 2.2-3.3gL(-1)d(-1) was obtained in the FBR experiment. The acidic influent was neutralized and the highest metal precipitation rates were 0.84g FeL(-1)d(-1) and 15mg ZnL(-1)d(-1). The sulfate reduction rate in the FBR was limited by the acetate oxidation rate of the sulfate-reducing bacteria. PMID:20137922

  11. 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

  12. Effect of bioaugmentation and biostimulation on sulfate-reducing column startup captured by functional gene profiling.

    PubMed

    Pereyra, Luciana P; Hiibel, Sage R; Perrault, Elizabeth M; Reardon, Kenneth F; Pruden, Amy

    2012-10-01

    Sulfate-reducing permeable reactive zones (SR-PRZs) depend upon a complex microbial community to utilize a lignocellulosic substrate and produce sulfides, which remediate mine drainage by binding heavy metals. To gain insight into the impact of the microbial community composition on the startup time and pseudo-steady-state performance, functional genes corresponding to cellulose-degrading (CD), fermentative, sulfate-reducing, and methanogenic microorganisms were characterized in columns simulating SR-PRZs using quantitative polymerase chain reaction (qPCR) and denaturing gradient gel electrophoresis (DGGE). Duplicate columns were bioaugmented with sulfate-reducing or CD bacteria or biostimulated with ethanol or carboxymethyl cellulose and compared with baseline dairy manure inoculum and uninoculated controls. Sulfate removal began after ~ 15 days for all columns and pseudo-steady state was achieved by Day 30. Despite similar performance, DGGE profiles of 16S rRNA gene and functional genes at pseudo-steady state were distinct among the column treatments, suggesting the potential to control ultimate microbial community composition via bioaugmentation and biostimulation. qPCR revealed enrichment of functional genes in all columns between the initial and pseudo-steady-state time points. This is the first functional gene-based study of CD, fermentative and sulfate-reducing bacteria and methanogenic archaea in a lignocellulose-based environment and provides new qualitative and quantitative insight into startup of a complex microbial system. PMID:22587594

  13. 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.

  14. 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

  15. 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.

  16. Transition from Anaerobic to Aerobic Growth Conditions for the Sulfate-Reducing Bacterium Desulfovibrio oxyclinae Results in Flocculation

    PubMed Central

    Sigalevich, Pavel; Meshorer, Eran; Helman, Yael; Cohen, Yehuda

    2000-01-01

    A chemostat culture of the sulfate-reducing bacterium Desulfovibrio oxyclinae isolated from the oxic layer of a hypersaline cyanobacterial mat was grown anaerobically and then subjected to gassing with 1% oxygen, both at a dilution rate of 0.05 h?1. The sulfate reduction rate under anaerobic conditions was 370 nmol of SO42? mg of protein?1 min?1. At the onset of aerobic gassing, sulfate reduction decreased by 40%, although viable cell numbers did not decrease. After 42 h, the sulfate reduction rate returned to the level observed in the anaerobic culture. At this stage the growth yield increased by 180% compared to the anaerobic culture to 4.4 g of protein per mol of sulfate reduced. Protein content per cell increased at the same time by 40%. The oxygen consumption rate per milligram of protein measured in washed cell suspensions increased by 80%, and the thiosulfate reduction rate of the same samples increased by 29% with lactate as the electron donor. These findings indicated possible oxygen-dependent enhancement of growth. After 140 h of growth under oxygen flux, formation of cell aggregates 0.1 to 3 mm in diameter was observed. Micrometer-sized aggregates were found to form earlier, during the first hours of exposure to oxygen. The respiration rate of D. oxyclinae was sufficient to create anoxia inside clumps larger than 3 ?m, while the levels of dissolved oxygen in the growth vessel were 0.7 0.5 ?M. Aggregation of sulfate-reducing bacteria was observed within a Microcoleus chthonoplastes-dominated layer of a cyanobacterial mat under daily exposure to oxygen concentrations of up to 900 ?M. Desulfonema-like sulfate-reducing bacteria were also common in this environment along with other nonaggregated sulfate-reducing bacteria. Two-dimensional mapping of sulfate reduction showed heterogeneity of sulfate reduction activity in this oxic zone. PMID:11055956

  17. 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.

  18. Incorporation of either molybdenum or tungsten into formate dehydrogenase from Desulfovibrio alaskensis NCIMB 13491; EPR assignment of the proximal iron-sulfur cluster to the pterin cofactor in formate dehydrogenases from sulfate-reducing bacteria.

    PubMed

    Brondino, Carlos D; Passeggi, Mario C G; Caldeira, Jorge; Almendra, Maria J; Feio, Maria J; Moura, Jose J G; Moura, Isabel

    2004-03-01

    We report the characterization of the molecular properties and EPR studies of a new formate dehydrogenase (FDH) from the sulfate-reducing organism Desulfovibrio alaskensis NCIMB 13491. FDHs are enzymes that catalyze the two-electron oxidation of formate to carbon dioxide in several aerobic and anaerobic organisms. D. alaskensis FDH is a heterodimeric protein with a molecular weight of 126+/-2 kDa composed of two subunits, alpha=93+/-3 kDa and beta=32+/-2 kDa, which contains 6+/-1 Fe/molecule, 0.4+/-0.1 Mo/molecule, 0.3+/-0.1 W/molecule, and 1.3+/-0.1 guanine monophosphate nucleotides. The UV-vis absorption spectrum of D. alaskensis FDH is typical of an iron-sulfur protein with a broad band around 400 nm. Variable-temperature EPR studies performed on reduced samples of D. alaskensis FDH showed the presence of signals associated with the different paramagnetic centers of D. alaskensis FDH. Three rhombic signals having g-values and relaxation behavior characteristic of [4Fe-4S] clusters were observed in the 5-40 K temperature range. Two EPR signals with all the g-values less than two, which accounted for less than 0.1 spin/protein, typical of mononuclear Mo(V) and W(V), respectively, were observed. The signal associated with the W(V) ion has a larger deviation from the free electron g-value, as expected for tungsten in a d(1) configuration, albeit with an unusual relaxation behavior. The EPR parameters of the Mo(V) signal are within the range of values typically found for the slow-type signal observed in several Mo-containing proteins belonging to the xanthine oxidase family of enzymes. Mo(V) resonances are split at temperatures below 50 K by magnetic coupling with one of the Fe/S clusters. The analysis of the inter-center magnetic interaction allowed us to assign the EPR-distinguishable iron-sulfur clusters with those seen in the crystal structure of a homologous enzyme. PMID:14669076

  19. 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.

  20. 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.

  1. 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

  2. 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

  3. 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

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

    PubMed

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

    2013-08-13

    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

  5. 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 filtered through a 0.22 μ m sterile nylon filter, stained with phosphotungstic acid (PTA), and examined using transmission electron microscopy (TEM). TEM revealed the presence of viral like particles in the culture exposed to mytomycin C. Together these results suggest an active infection with a lysogenic bacteriophage in the model metal reducing bacteria, Geobacter spp., which could affect metabolic physiology and subsequently metal reduction in environmental systems.

  6. 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

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

    NASA Astrophysics Data System (ADS)

    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.

  8. Anaerobic Degradation of Ethylbenzene by a New Type of Marine Sulfate-Reducing Bacterium

    PubMed Central

    Kniemeyer, Olaf; Fischer, Thomas; Wilkes, Heinz; Glöckner, Frank Oliver; Widdel, Friedrich

    2003-01-01

    Anaerobic degradation of the aromatic hydrocarbon ethylbenzene was studied with sulfate as the electron acceptor. Enrichment cultures prepared with marine sediment samples from different locations showed ethylbenzene-dependent reduction of sulfate to sulfide and always contained a characteristic cell type that formed gas vesicles towards the end of growth. A pure culture of this cell type, strain EbS7, was isolated from sediment from Guaymas Basin (Gulf of California). Complete mineralization of ethylbenzene coupled to sulfate reduction was demonstrated in growth experiments with strain EbS7. Sequence analysis of the 16S rRNA gene revealed a close relationship between strain EbS7 and the previously described marine sulfate-reducing strains NaphS2 and mXyS1 (similarity values, 97.6 and 96.2%, respectively), which grow anaerobically with naphthalene and m-xylene, respectively. However, strain EbS7 did not oxidize naphthalene, m-xylene, or toluene. Other compounds utilized by strain EbS7 were phenylacetate, 3-phenylpropionate, formate, n-hexanoate, lactate, and pyruvate. 1-Phenylethanol and acetophenone, the characteristic intermediates in anaerobic ethylbenzene degradation by denitrifying bacteria, neither served as growth substrates nor were detectable as metabolites by gas chromatography-mass spectrometry in ethylbenzene-grown cultures of strain EbS7. Rather, (1-phenylethyl)succinate and 4-phenylpentanoate were detected as specific metabolites in such cultures. Formation of these intermediates can be explained by a reaction sequence involving addition of the benzyl carbon atom of ethylbenzene to fumarate, carbon skeleton rearrangement of the succinate moiety (as a thioester), and loss of one carboxyl group. Such reactions are analogous to those suggested for anaerobic n-alkane degradation and thus differ from the initial reactions in anaerobic ethylbenzene degradation by denitrifying bacteria which employ dehydrogenations. PMID:12570993

  9. Evaluation of organic substrates to enhance the sulfate-reducing activity in phosphogypsum.

    PubMed

    Castillo, Julio; Pérez-López, Rafael; Sarmiento, Aguasanta M; Nieto, José M

    2012-11-15

    Several experiments were conducted to evaluate the activity and growth of sulfate-reducing bacteria (SRB) in a metal-rich culture medium (approx. 250 mg/L Fe, 75 mg/L Zn and Cu, 10mg/L Cd) with phosphogypsum as bacterial inoculum. Phosphogypsum was collected from the stack covering the salt-marshes of the Tinto river (SW Spain). Three organic amendments were used as carbon sources, two low-cost wastes (horse manure and legume compost) and one sample of natural soil (vegetal cover). In the experiments, sulfate was reduced to sulfide during the growth of SRB populations, and concentrations were decreased in the solution. Metal concentrations also decreased to values below the detection limit. Metal removal took place by precipitation of newly-formed sulfides. Pyrite-S was the main sulfide component (approx. 200 μmol/g and 80% of pyritization) and occurred mainly as framboidal grains and rarely as isolated polyhedral crystals. Horse manure was the most successful organic substrate to promote SRB activity (sulfate removal of 61%), followed by vegetal cover (49%) and legume compost (31%). These findings propose the possibility of using naturally-occurring SRB in the phosphogypsum for bioremediation strategies based on natural soil covers with organic amendments. PMID:23063915

  10. 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

  11. 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

  12. 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.

  13. 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

  14. 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

  15. Desulfovibrio hydrothermalis sp. nov., a novel sulfate-reducing bacterium isolated from hydrothermal vents.

    PubMed

    Alazard, D; Dukan, S; Urios, A; Verhé, F; Bouabida, N; Morel, F; Thomas, P; Garcia, J L; Ollivier, B

    2003-01-01

    Mesophilic, hydrogenotrophic, sulfate-reducing bacteria were isolated from a deep-sea hydrothermal chimney sample collected at 13 degrees N on the East-Pacific Rise at a depth of 2,600 m. Two strains (BL5 and H9) were found to be phylogenetically similar to Desulfovibrio profundus (similarity >99%), whereas two other strains (H1 and AM13T) were found to be phylogenetically distinct (similarity 96.4%) from Desulfovibrio zosterae, their closest relative. Strain AM13T was characterized further. It was a barophilic, Gram-negative, non-sporulating, motile, vibrio-shaped or sigmoid bacterium possessing desulfoviridin. It grew at temperatures ranging from 20 to 40 degrees C, with an optimum at 35 degrees C in the presence of 2.5% NaCl. The pH range for growth was 6.7-8.2 with an optimum around 7.8. Strain AM13T utilized H2/CO2, lactate, formate, ethanol, choline and glycerol as electron donors. Electron acceptors were sulfate, sulfite and thiosulfate, but not elemental sulfur or nitrate. The G + C content of DNA was 47 mol%. Strain AM13T (= DSM 14728T = CIP107303T) differed from D. zosterae not only phylogenetically, but also genomically (DNA-DNA reassociation value between the two bacteria was 23.8%) and phenotypically. This isolate is therefore proposed as the type strain of a novel species of the genus Desulfovibrio, Desulfovibrio hydrothermalis sp. nov. PMID:12656169

  16. 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...

  17. 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 attenuation of environmental contaminants. Understanding of diversity and physiology of anaerobic PAH degradation will contribute to remediation efforts of low-oxygen environments such as aquifers or river sediments.

  18. Multiple Lateral Transfers of Dissimilatory Sulfite Reductase Genes between Major Lineages of Sulfate-Reducing Prokaryotes

    PubMed Central

    Klein, Michael; Friedrich, Michael; Roger, Andrew J.; Hugenholtz, Philip; Fishbain, Susan; Abicht, Heike; Blackall, Linda L.; Stahl, David A.; Wagner, Michael

    2001-01-01

    A large fragment of the dissimilatory sulfite reductase genes (dsrAB) was PCR amplified and fully sequenced from 30 reference strains representing all recognized lineages of sulfate-reducing bacteria. In addition, the sequence of the dsrAB gene homologs of the sulfite reducer Desulfitobacterium dehalogenans was determined. In contrast to previous reports, comparative analysis of all available DsrAB sequences produced a tree topology partially inconsistent with the corresponding 16S rRNA phylogeny. For example, the DsrAB sequences of several Desulfotomaculum species (low G+C gram-positive division) and two members of the genus Thermodesulfobacterium (a separate bacterial division) were monophyletic with ?-proteobacterial DsrAB sequences. The most parsimonious interpretation of these data is that dsrAB genes from ancestors of as-yet-unrecognized sulfate reducers within the ?-Proteobacteria were laterally transferred across divisions. A number of insertions and deletions in the DsrAB alignment independently support these inferred lateral acquisitions of dsrAB genes. Evidence for a dsrAB lateral gene transfer event also was found within the ?-Proteobacteria, affecting Desulfobacula toluolica. The root of the dsr tree was inferred to be within the Thermodesulfovibrio lineage by paralogous rooting of the alpha and beta subunits. This rooting suggests that the dsrAB genes in Archaeoglobus species also are the result of an ancient lateral transfer from a bacterial donor. Although these findings complicate the use of dsrAB genes to infer phylogenetic relationships among sulfate reducers in molecular diversity studies, they establish a framework to resolve the origins and diversification of this ancient respiratory lifestyle among organisms mediating a key step in the biogeochemical cycling of sulfur. PMID:11567003

  19. 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 community composition. CCA of Shannon diversity data after one pore volume revealed that zinc removal, walnut shell content, and abundance of delta-Proteobacteria (sulfate reducing organisms) were all corresponding elements. However, after several pore volumes, the walnut shell column was no longer removing Zn as effectively, and community shifts were observed throughout the columns. Analysis of field and laboratory scale microbiological and geochemical shifts, in parallel, gives insight into key biogeochemical variables linked to the performance of passive remediation systems used for the treatment of contaminated MIW, while also providing further insight into metal immobilization at the microbe-mineral interface.

  20. [Research on removal efficiency of Cd (II)-bearing wastewater by sulfate-reducing biological filter].

    PubMed

    Wu, Xuan; Tan, Ke-Yan; Hu, Xi-Jia; Gu, Yun; Yang, Hong

    2014-04-01

    At the temperature of 18.0-22.3 degrees C, biological carriers were produce from pure SRB and zeolite by the embedding immobilized method, and a sulfate-reducing biological filter filled with filter carriers was built to treat cadmium-containing wastewater. Experimental research on removal efficiency of Cd2+, COD and SO4(2-) in wastewater by the biological filter was carried out after SRB domestication. Results show that cadmium can be removed satisfactorily from wastewater using SRB by the biological filter filled with sulfate-reducing bacteria. When the filtration rate was 0.4 m x h(-1) and the cadmium concentration in wastewater was not more than 15 mg x L(-1), the processing efficiency was the best. In the formal running period, the removal rates of Cd2+, COD and SO4(2-) by the biological filter were more than 99%, 75% and 50%. The effluent Cd2+ concentration was less than 0.1 mg x L(-1), which could meet the cadmium emission requirements in the wastewater quality standards for discharge to municipal sewers (CJ 343-2010). The removal of Cd2+, COD and SO4(2-) by biological filter mainly occurs in the top 60 cm of the filter bed during stable operation. When the filtration rate was less than 0.6 m x h(-1), Cd(2+) can be removed by the biological filter with high efficiency and stability. PMID:24946589

  1. 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

  2. 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.

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

    SciTech Connect

    Spring, Stefan; Visser, Michael; Lu, Megan; Copeland, A; Lapidus, Alla L.; Lucas, Susan; Cheng, Jan-Fang; Han, Cliff; Tapia, Roxanne; Goodwin, Lynne A.; Pitluck, Sam; Ivanova, N; Land, Miriam L; Hauser, Loren John; Larimer, Frank W; Rohde, Manfred; Goker, Markus; Detter, J. Chris; Kyrpides, Nikos C; Woyke, Tanja; Schaap, Peter J; Plugge, Caroline M.; Muyzer, Gerard; Kuever, Jan; Pereira, Ines 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 pub- lished, and was sequenced as part of the DOE Joint Genome Institute Community Sequencing Program 2009.

  4. Bacteria Penetrate the Inner Mucus Layer before Inflammation in the Dextran Sulfate Colitis Model

    PubMed Central

    Johansson, Malin E. V.; Gustafsson, Jenny K.; Sjöberg, Karolina E.; Petersson, Joel; Holm, Lena; Sjövall, Henrik; Hansson, Gunnar C.

    2010-01-01

    Background Protection of the large intestine with its enormous amount of commensal bacteria is a challenge that became easier to understand when we recently could describe that colon has an inner attached mucus layer devoid of bacteria (Johansson et al. (2008) Proc. Natl. Acad. Sci. USA 105, 15064–15069). The bacteria are thus kept at a distance from the epithelial cells and lack of this layer, as in Muc2-null mice, allow bacteria to contact the epithelium. This causes colitis and later on colon cancer, similar to the human disease Ulcerative Colitis, a disease that still lacks a pathogenetic explanation. Dextran Sulfate (DSS) in the drinking water is the most widely used animal model for experimental colitis. In this model, the inflammation is observed after 3–5 days, but early events explaining why DSS causes this has not been described. Principal Findings When mucus formed on top of colon explant cultures were exposed to 3% DSS, the thickness of the inner mucus layer decreased and became permeable to 2 µm fluorescent beads after 15 min. Both DSS and Dextran readily penetrated the mucus, but Dextran had no effect on thickness or permeability. When DSS was given in the drinking water to mice and the colon was stained for bacteria and the Muc2 mucin, bacteria were shown to penetrate the inner mucus layer and reach the epithelial cells already within 12 hours, long before any infiltration of inflammatory cells. Conclusion DSS thus causes quick alterations in the inner colon mucus layer that makes it permeable to bacteria. The bacteria that reach the epithelial cells probably trigger an inflammatory reaction. These observations suggest that altered properties or lack of the inner colon mucus layer may be an initial event in the development of colitis. PMID:20805871

  5. 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

  6. 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. PMID:26800443

  7. 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. PMID:26800443

  8. 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.

  9. 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.

  10. 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

  11. 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 growth with H2. PMID:24672515

  12. 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

  13. 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

  14. Genome Sequence of the Moderately Acidophilic Sulfate-Reducing Firmicute Desulfosporosinus acididurans (Strain M1T).

    PubMed

    Petzsch, Patrick; Poehlein, Anja; Johnson, D Barrie; Daniel, Rolf; Schlömann, Michael; Mühling, Martin

    2015-01-01

    Microbial dissimilatory sulfate reduction is commonplace in many anaerobic environments, though few acidophilic bacteria are known to mediate this process. We report the 4.64-Mb draft genome of the type strain of the moderate acidophile Desulfosporosinus acididurans, which was isolated from acidic sediment in a river draining the Soufrière volcano, Montserrat. PMID:26251501

  15. 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

  16. Fatty Acids and Stable Carbon Isotopes of a Sulfate-Reducing Bacterium: Implications for Carbon Cycling in Organic-Rich Marine Sediments

    NASA Astrophysics Data System (ADS)

    McBeth, J.; Giles, B.; Ye, E.; Li, Y.; Zhang, C. L.; Wall, J. D.; Huang, Y.; Horita, J.; Cole, D. R.

    2001-12-01

    Sulfate-reducing bacteria have characteristic lipid biomarkers, which help delineate carbon cycling pathways under sulfate-reducing conditions. This is especially important for marine sediments because of the predominance of sulfate reduction in such environments. Little research has been done to determine carbon isotope fractionations associated with lipid biomarkers of known sulfate-reducing bacteria. We examined the fatty acid compositions and their carbon isotope ratios of Desulfovibrio desulfuricans G-20 using lactate, pyruvate, or formate as the electron donor and sulfate as the electron acceptor. No CO2 or HCO3- was added during experimentation. G-20 grew well with lactate and pyruvate but only marginally, if at all, with formate. Diagnostic fatty acids of iso- and anteiso-15:0 and 17:0 were higher in formate and lactate cultures (5-17%) than in pyruvate cultures (2.5-5.0%). Carbon isotope fractionation of these and other fatty acids against total biomass was similar under lactate (-10.7 to -15.1\\permil) and pyruvate (-9.9 to -15.7\\permil) conditions, which may be due to the fact that no carbon splitting occurs during lactate degradation to pyruvate (DeNiro and Epstein, 1977). The fractionation was much smaller (0.1 to -8.21\\permil) under formate conditions, suggesting that a different biosynthetic pathway may be utilized by G-20 when it is incubated with this substrate or it is carbon limited. The results indicate that carbon isotopes of lipid biomarkers may provide insight into metabolic pathways and have implications of carbon cycling by sulfate-reducing bacteria in hydrocarbon-rich environments where the bacteria can grow on different organic substrates. geosccz/research.html

  17. 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 (21-38%). Acid digests and micro-focused X-ray fluorescent and absorption spectroscopy revealed precipitation heterogeneities exist between surface samples taken near the front of the influent pipe (west) and downstream (east). Zinc was disproportionately immobilized at the front of the reactor (~10-fold higher), while a higher portion (~3-fold) of iron precipitates was observed downstream. Microfocused XAS further revealed matrix heterogeneities consisting of clusters of stellar shaped sulfur / iron precipitates. An enhanced understanding of the biogeochemistry of SRBRs has applications in passive remediation of contaminated MIW and an interdisciplinary understanding of metal immobilization at the microbe-mineral interface.

  18. Microbial diversity and community structure of a highly active anaerobic methane-oxidizing sulfate-reducing enrichment.

    PubMed

    Jagersma, G Christian; Meulepas, Roel J W; Heikamp-de Jong, Ineke; Gieteling, Jarno; Klimiuk, Adam; Schouten, Stefan; Damsté, Jaap S Sinninghe; Lens, Piet N L; Stams, Alfons J M

    2009-12-01

    Anaerobic oxidation of methane (AOM) is an important methane sink in the ocean but the microbes responsible for AOM are as yet resilient to cultivation. Here we describe the microbial analysis of an enrichment obtained in a novel submerged-membrane bioreactor system and capable of high-rate AOM (286 mumol g(dry weight)(-1) day(-1)) coupled to sulfate reduction. By constructing a clone library with subsequent sequencing and fluorescent in situ hybridization, we showed that the responsible methanotrophs belong to the ANME-2a subgroup of anaerobic methanotrophic archaea, and that sulfate reduction is most likely performed by sulfate-reducing bacteria commonly found in association with other ANME-related archaea in marine sediments. Another relevant portion of the bacterial sequences can be clustered within the order of Flavobacteriales but their role remains to be elucidated. Fluorescent in situ hybridization analyses showed that the ANME-2a cells occur as single cells without close contact to the bacterial syntrophic partner. Incubation with (13)C-labelled methane showed substantial incorporation of (13)C label in the bacterial C(16) fatty acids (bacterial; 20%, 44% and 49%) and in archaeal lipids, archaeol and hydroxyl-archaeol (21% and 20% respectively). The obtained data confirm that both archaea and bacteria are responsible for the anaerobic methane oxidation in a bioreactor enrichment inoculated with Eckernförde bay sediment. PMID:19703218

  19. 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

  20. 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

  1. Selenate removal in methanogenic and sulfate-reducing upflow anaerobic sludge bed reactors.

    PubMed

    Lenz, Markus; Hullebusch, Eric D Van; Hommes, Gregor; Corvini, Philippe F X; Lens, Piet N L

    2008-04-01

    This paper evaluates the use of upflow anaerobic sludge bed (UASB) bioreactors (30 degrees C, pH=7.0) to remove selenium oxyanions from contaminated waters (790 microg Se L(-1)) under methanogenic and sulfate-reducing conditions using lactate as electron donor. One UASB reactor received sulfate at different sulfate to selenate ratios, while another UASB was operated under methanogenic conditions for 132 days without sulfate in the influent. The selenate effluent concentrations in the sulfate-reducing and methanogenic reactor were 24 and 8 microg Se L(-1), corresponding to removal efficiencies of 97% and 99%, respectively. X-ray diffraction (XRD) analysis and sequential extractions showed that selenium was mainly retained as elemental selenium in the biomass. However, the total dissolved selenium effluent concentrations amounted to 73 and 80 microg Se L(-1), respectively, suggesting that selenate was partly converted to another selenium compound, most likely colloidally dispersed Se(0) nanoparticles. Possible intermediates of selenium reduction (selenite, dimethylselenide, dimethyldiselenide, H(2)Se) could not be detected. Sulfate reducers removed selenate at molar excess of sulfate to selenate (up to a factor of 2600) and elevated dissolved sulfide concentrations (up to 168 mg L(-1)), but selenium removal efficiencies were limited by the applied sulfate-loading rate. In the methanogenic bioreactor, selenate and dissolved selenium removal were independent of the sulfate load, but inhibited by sulfide (101 mg L(-1)). The selenium removal efficiency of the methanogenic UASB abruptly improved after 58 days of operation, suggesting that a specialized selenium-converting population developed in the reactor. This paper demonstrates that both sulfate-reducing and methanogenic UASB reactors can be applied to remove selenate from contaminated natural waters and anthropogenic waste streams, e.g. agricultural drainage waters, acid mine drainage and flue gas desulfurization bleeds. PMID:18177686

  2. 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.

  3. 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 environmental perturbations.

  4. 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

  5. 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 with H2 as the sole electron donor, and CO2 as primary carbon source. The fractionation of sulfur isotopes was measured in batch cultures and in a thermal gradient block over the full temperature range of growth (40-80° C). For experiments in the gradient block, cell-specific rates of sulfate reduction increased with increasing temperatures to 70° C after which sulfate-reduction rates rapidly decreased. The range of fractionations (1.5-10‰ ) was typical for growth with hydrogen as the electron donor. Fractionations decreased with increasing temperature from 40--60° C, and increased with increasing temperatures from 60-80° C. Growth under H2-limited conditions in a fed-batch culture revealed high fractionations of 24-37‰ . This is the first report of sulfur isotope fractionation under H2 limited growth and indicates that large fractionations are produced when H2 is supplied as a limiting substrate. Our results suggest that fractionation is controlled by the competition of forward and reverse enzymatic reaction rates during sulfate reduction and by sulfate transport into the cell.

  6. Desulfosporosinus acididurans sp. nov.: an acidophilic sulfate-reducing bacterium isolated from acidic sediments.

    PubMed

    Sánchez-Andrea, Irene; Stams, Alfons J M; Hedrich, Sabrina; Ňancucheo, Ivan; Johnson, D Barrie

    2015-01-01

    Three strains of sulfate-reducing bacteria (M1(T), D, and E) were isolated from acidic sediments (White river and Tinto river) and characterized phylogenetically and physiologically. All three strains were obligately anaerobic, mesophilic, spore-forming straight rods, stained Gram-negative and displayed variable motility during active growth. The pH range for growth was 3.8-7.0, with an optimum at pH 5.5. The temperature range for growth was 15-40 °C, with an optimum at 30 °C. Strains M1(T), D, and E used a wide range of electron donors and acceptors, with certain variability within the different strains. The nominated type strain (M1(T)) used ferric iron, nitrate, sulfate, elemental sulfur, and thiosulfate (but not arsenate, sulfite, or fumarate) as electron acceptors, and organic acids (formate, lactate, butyrate, fumarate, malate, and pyruvate), alcohols (glycerol, methanol, and ethanol), yeast extract, and sugars (xylose, glucose, and fructose) as electron donors. It also fermented some substrates such as pyruvate and formate. Strain M1(T) tolerated up to 50 mM ferrous iron and 10 mM aluminum, but was inhibited by 1 mM copper. On the basis of phenotypic, phylogenetic, and genetic characteristics, strains M1(T), D, and E represent a novel species within the genus Desulfosporosinus, for which the name Desulfosporosinus acididurans sp. nov. is proposed. The type strain is M1(T) (=DSM 27692(T) = JCM 19471(T)). Strain M1(T) was the first acidophilic SRB isolated, and it is the third described species of acidophilic SRB besides Desulfosporosinus acidiphilus and Thermodesulfobium narugense. PMID:25370366

  7. 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

  8. 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.

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

    SciTech Connect

    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; 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, Loanna; Woyke, Tanja; Arkin, Adam P.; Dehal, Paramvir; Chivian, Dylan; Criddle, Craig S.; Wu, Weimin; Chakraborty, Romy; Hazen, Terry C.; Fields, Matthew W.

    2015-03-12

    Desulfovibrio carbinoliphilus subsp. oakridgensis FW-101-2B is an anaerobic, organic acid/alcohol-oxidizing, sulfate-reducing ?-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.

  10. 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.

  11. 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

  12. Phylogenetic Analysis Reveals Multiple Lateral Transfers of Adenosine-5?-Phosphosulfate Reductase Genes among Sulfate-Reducing Microorganisms

    PubMed Central

    Friedrich, Michael W.

    2002-01-01

    Lateral gene transfer affects the evolutionary path of key genes involved in ancient metabolic traits, such as sulfate respiration, even more than previously expected. In this study, the phylogeny of the adenosine-5?-phosphosulfate (APS) reductase was analyzed. APS reductase is a key enzyme in sulfate respiration present in all sulfate-respiring prokaryotes. A newly developed PCR assay was used to amplify and sequence a fragment (?900 bp) of the APS reductase gene, apsA, from a taxonomically wide range of sulfate-reducing prokaryotes (n = 60). Comparative phylogenetic analysis of all obtained and available ApsA sequences indicated a high degree of sequence conservation in the region analyzed. However, a comparison of ApsA- and 16S rRNA-based phylogenetic trees revealed topological incongruences affecting seven members of the Syntrophobacteraceae and three members of the Nitrospinaceae, which were clearly monophyletic with gram-positive sulfate-reducing bacteria (SRB). In addition, Thermodesulfovibrio islandicus and Thermodesulfobacterium thermophilum, Thermodesulfobacterium commune, and Thermodesulfobacterium hveragerdense clearly branched off between the radiation of the ?-proteobacterial gram-negative SRB and the gram-positive SRB and not close to the root of the tree as expected from 16S rRNA phylogeny. The most parsimonious explanation for these discrepancies in tree topologies is lateral transfer of apsA genes across bacterial divisions. Similar patterns of insertions and deletions in ApsA sequences of donor and recipient lineages provide additional evidence for lateral gene transfer. From a subset of reference strains (n = 25), a fragment of the dissimilatory sulfite reductase genes (dsrAB), which have recently been proposed to have undergone multiple lateral gene transfers (M. Klein et al., J. Bacteriol. 183:60286035, 2001), was also amplified and sequenced. Phylogenetic comparison of DsrAB- and ApsA-based trees suggests a frequent involvement of gram-positive and thermophilic SRB in lateral gene transfer events among SRB. PMID:11741869

  13. 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

  14. Benzene oxidation under sulfate-reducing conditions in columns simulating in situ conditions.

    PubMed

    Vogt, Carsten; Gödeke, Stefan; Treutler, Hanns-Christian; Weiss, Holger; Schirmer, Mario; Richnow, Hans-Hermann

    2007-10-01

    The oxidation of benzene under sulfate-reducing conditions was examined in column and batch experiments under close to in situ conditions. Mass balances and degradation rates for benzene oxidation were determined in four sand and four lava granules filled columns percolated with groundwater from an anoxic benzene-contaminated aquifer. The stoichiometry of oxidized benzene, produced hydrogen carbonate and reduced sulfate correlated well with the theoretical equation for mineralization of benzene with sulfate as electron acceptor. Mean retention times of water in four columns were determined using radon ((222)Rn) as tracer. The retention times were used to calculate average benzene oxidation rates of 8-36 microM benzene day(-1). Benzene-degrading, sulfide-producing microcosms were successfully established from sand material of all sand filled columns, strongly indicating that the columns were colonized by anoxic benzene-degrading microorganisms. In general, these data indicate a high potential for Natural Attenuation of benzene under sulfate-reducing conditions at the field site Zeitz. In spite of this existing potential to degrade benzene with sulfate as electron acceptor, the benzene plume at the field site is much longer than expected if benzene would be degraded at the rates observed in the column experiment, indicating that benzene oxidation under sulfate-reducing conditions is limited in situ. PMID:17160546

  15. Systematic mapping of two component response regulators to gene targets in a model sulfate reducing bacterium

    PubMed Central

    2011-01-01

    Background Two component regulatory systems are the primary form of signal transduction in bacteria. Although genomic binding sites have been determined for several eukaryotic and bacterial transcription factors, comprehensive identification of gene targets of two component response regulators remains challenging due to the lack of knowledge of the signals required for their activation. We focused our study on Desulfovibrio vulgaris Hildenborough, a sulfate reducing bacterium that encodes unusually diverse and largely uncharacterized two component signal transduction systems. Results We report the first systematic mapping of the genes regulated by all transcriptionally acting response regulators in a single bacterium. Our results enabled functional predictions for several response regulators and include key processes of carbon, nitrogen and energy metabolism, cell motility and biofilm formation, and responses to stresses such as nitrite, low potassium and phosphate starvation. Our study also led to the prediction of new genes and regulatory networks, which found corroboration in a compendium of transcriptome data available for D. vulgaris. For several regulators we predicted and experimentally verified the binding site motifs, most of which were discovered as part of this study. Conclusions The gene targets identified for the response regulators allowed strong functional predictions to be made for the corresponding two component systems. By tracking the D. vulgaris regulators and their motifs outside the Desulfovibrio spp. we provide testable hypotheses regarding the functions of orthologous regulators in other organisms. The in vitro array based method optimized here is generally applicable for the study of such systems in all organisms. PMID:21992415

  16. 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 rates, chemostat studies were conducted with strain RCH1. Genes assayed by qPCR and RT-qPCR included aprB (APS reductase, beta subunit), dsrA (dissimilatory sulfite reductase, alpha subunit), cyc3 (cytochrome c3), and trxB (thioredoxin reductase). Strong linear relationships were observed between sulfate reduction rates and the gene and transcript copy numbers of all of the targeted genes. These results suggest that use of gene and transcript copy numbers in groundwater samples may be a useful approach for estimating in situ metabolic rates of sulfate-reducing bacteria during Cr bioremediation.

  17. In situ BTEX biotransformation under intrinsic and nitrate- and sulfate-reducing conditions

    SciTech Connect

    Reinhard, M.; Shang, S.; Kitanidis, P.K.; Orwin, E.

    1996-10-01

    Controlled amounts of BTEX compounds added to slugs of treated ground water were released into a gasoline-contaminated aquifer at Seal Beach (CA). In a series of studies, the slugs 470 to 1,700 L in volume were released into the aquifer. To evaluate nitrate-reducing and sulfate-reducing conditions, the injectate was also deionized and augmented with 200-300 {mu}g/L BTEX, nitrate or sulfate, and background electrolytes. Under intrinsic conditions, transformation appeared to be limited to slow removal of toluene and m,p-xylene. Under nitrate-reducing conditions, toluene, ethylbenzene, m-xylene, and o-xylene were transformed without a lag in less than 4, 6, and 70 days, respectively. Under sulfate-reducing conditions, toluene, m-xylene and o-xylene were completely transformed in less than 50 days, and ethylbenzene was removed in 60 days. Benzene was slowly removed, but the mechanism of removal could not be ascertained.

  18. 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 biocompetitive exclusion was the major process. The results demonstrate that stable isotope data can contribute unique information for understanding complex microbial processes in nitrate- and sulfate-reducing systems, and offer important information for the management of H 2S problems in oil reservoirs and elsewhere.

  19. In situ BTEX biotransformation under enhanced nitrate- and sulfate-reducing conditions

    SciTech Connect

    Reinhard, M.; Shang, S.; Kitanidis, P.K.; Orwin, E.; Hopkins, G.D.; LeBron, C.A.

    1997-01-01

    In situ anaerobic biotransformation of BTEX (benzene, toluene, ethylbenzene, o-xylene, and m-xylene) was investigated under enhanced nitrate- and sulfate-reducing conditions. Controlled amounts of BTEX compounds added to slugs of treated groundwater were released into a gasoline-contaminated aquifer at Seal Beach, CA. In a series of studies, the slugs, 470-1700 L in volume, were released into the aquifer through a multi-port injection/extraction well and were subsequently withdrawn over a 2-3 month period. To evaluate unamended in situ conditions, the injectate was treated with granular activated carbon (GAC) and augmented with bromide as a tracer. To evaluate nitrate- and sulfate-reducing conditions, the injectate was also deionized and augmented with 200-300 {mu}g/L BTEX, nitrate or sulfate, and background electrolytes. Under unamended conditions, transformation appeared to be limited to the slow removal of toluene and m,p-xylene (i.e. sum of m+p-xylene). Under nitrate-reducing conditions, toluene, ethylbenzene, and m-xylene were transformed without a lag phase in less than 10 days, and o-xylene was transformed in 72 days. Under sulfate-reducing conditions, toluene, m-xylene and o-xylene were completely transformed in less then 50 days, and ethylbenzene was removed in 60 days. Benzene appeared to be removed under sulfate-reducing conditions, but the trend was pronounced only at some levels. 47 refs., 11 figs., 2 tabs.

  20. Anaerobic degradation of p-xylene in sediment-free sulfate-reducing enrichment culture.

    PubMed

    Nakagawa, Tatsunori; Sato, Shinya; Fukui, Manabu

    2008-11-01

    Anaerobic degradation of p-xylene was studied with sulfate-reducing enrichment culture. The enrichment culture was established with sediment-free sulfate-reducing consortium on crude oil. The crude oil-degrading consortium prepared with marine sediment revealed that toluene, and xylenes among the fraction of alkylbenzene in the crude oil were consumed during the incubation. The PCR-denaturing gradient gel electrophoresis (DGGE) analysis of 16S rRNA gene for the p-xylene degrading sulfate-reducing enrichment culture showed the presence of the single dominant DGGE band pXy-K-13 coupled with p-xylene consumption and sulfide production. Sequence analysis of the DGGE band revealed a close relationship between DGGE band pXy-K-13 and the previously described marine sulfate-reducing strain oXyS1 (similarity value, 99%), which grow anaerobically with o-xylene. These results suggest that microorganism corresponding to pXy-K-13 is an important sulfate-reducing bacterium to degrade p-xylene in the enrichment culture. PMID:18409067

  1. Functional Genomics with a Comprehensive Library of Transposon Mutants for the Sulfate-Reducing Bacterium Desulfovibrio alaskensis G20

    PubMed Central

    Kuehl, Jennifer V.; Price, Morgan N.; Ray, Jayashree; Wetmore, Kelly M.; Esquivel, Zuelma; Kazakov, Alexey E.; Nguyen, Michelle; Kuehn, Raquel; Davis, Ronald W.; Hazen, Terry C.; Arkin, Adam P.

    2014-01-01

    ABSTRACT The genomes of sulfate-reducing bacteria remain poorly characterized, largely due to a paucity of experimental data and genetic tools. To meet this challenge, we generated an archived library of 15,477 mapped transposon insertion mutants in the sulfate-reducing bacterium Desulfovibrio alaskensis G20. To demonstrate the utility of the individual mutants, we profiled gene expression in mutants of six regulatory genes and used these data, together with 1,313 high-confidence transcription start sites identified by tiling microarrays and transcriptome sequencing (5′ RNA-Seq), to update the regulons of Fur and Rex and to confirm the predicted regulons of LysX, PhnF, PerR, and Dde_3000, a histidine kinase. In addition to enabling single mutant investigations, the D. alaskensis G20 transposon mutants also contain DNA bar codes, which enables the pooling and analysis of mutant fitness for thousands of strains simultaneously. Using two pools of mutants that represent insertions in 2,369 unique protein-coding genes, we demonstrate that the hypothetical gene Dde_3007 is required for methionine biosynthesis. Using comparative genomics, we propose that Dde_3007 performs a missing step in methionine biosynthesis by transferring a sulfur group to O-phosphohomoserine to form homocysteine. Additionally, we show that the entire choline utilization cluster is important for fitness in choline sulfate medium, which confirms that a functional microcompartment is required for choline oxidation. Finally, we demonstrate that Dde_3291, a MerR-like transcription factor, is a choline-dependent activator of the choline utilization cluster. Taken together, our data set and genetic resources provide a foundation for systems-level investigation of a poorly studied group of bacteria of environmental and industrial importance. PMID:24865553

  2. 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.

  3. Distribution of anaerobic methane-oxidizing and sulfate-reducing communities in the G11 Nyegga pockmark, Norwegian Sea.

    PubMed

    Lazar, Cassandre Sara; Dinasquet, Julie; L'Haridon, Stéphane; Pignet, Patricia; Toffin, Laurent

    2011-11-01

    Pockmarks are seabed geological structures sustaining methane seepage in cold seeps. Based on RNA-derived sequences the active fraction of the archaeal community was analysed in sediments associated with the G11 pockmark, in the Nyegga region of the Norwegian Sea. The anaerobic methanotrophic Archaea (ANME) and sulfate-reducing bacteria (SRB) communities were studied as well. The vertical distribution of the archaeal community assessed by PCR-DGGE highlighted the presence of ANME-2 in surface sediments, and ANME-1 in deeper sediments. Enrichments of methanogens showed the presence of hydrogenotrophic methanogens of the Methanogenium genus in surface sediment layers as well. The active fraction of the archaeal community was uniquely composed of ANME-2 in the shallow sulfate-rich sediments. Functional methyl coenzyme M reductase gene libraries showed that sequences affiliated with the ANME-1 and ANME-3 groups appeared in the deeper sediments but ANME-2 dominated both surface and deeper layers. Finally, dissimilatory sulfite reductase gene libraries revealed a high SRB diversity (i.e. Desulfobacteraceae, Desulfobulbaceae, Syntrophobacteraceae and Firmicutes) in the shallow sulfate-rich sediments. The SRB diversity was much lower in the deeper section. Overall, these results show that the microbial community in sediments associated with a pockmark harbour classical cold seep ANME and SRB communities. PMID:21751028

  4. 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...

  5. 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 ...

  6. 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

  7. Magnesium Sulfate Only Slightly Reduces the Shivering Threshold in Humans

    PubMed Central

    Wadhwa, Anupama; Sengupta, Papiya; Durrani, Jaleel; Akça, Ozan; Lenhardt, Rainer; Sessler, Daniel I.

    2005-01-01

    Background: Hypothermia may be an effective treatment for stroke or acute myocardial infarction; however, it provokes vigorous shivering, which causes potentially dangerous hemodynamic responses and prevents further hypothermia. Magnesium is an attractive antishivering agent because it is used for treatment of postoperative shivering and provides protection against ischemic injury in animal models. We tested the hypothesis that magnesium reduces the threshold (triggering core temperature) and gain of shivering without substantial sedation or muscle weakness. Methods: We studied nine healthy male volunteers (18-40 yr) on two randomly assigned treatment days: 1) Control and 2) Magnesium (80 mg·kg-1 followed by infusion at 2 g·h-1). Lactated Ringer's solution (4°C) was infused via a central venous catheter over a period of approximately 2 hours to decrease tympanic membrane temperature ≈1.5°C·h-1. A significant and persistent increase in oxygen consumption identified the threshold. The gain of shivering was determined by the slope of oxygen consumption vs. core temperature regression. Sedation was evaluated using verbal rating score (VRS, 0-10) and bispectral index of the EEG (BIS). Peripheral muscle strength was evaluated using dynamometry and spirometry. Data were analyzed using repeated-measures ANOVA; P<0.05 was statistically significant. Results: Magnesium reduced the shivering threshold (36.3±0.4 [mean±SD] vs. 36.6±0.3°C, P=0.040). It did not affect the gain of shivering (Control: 437±289, Magnesium: 573±370 ml·min-1·°C-1, P=0.344). The magnesium bolus did not produce significant sedation or appreciably reduce muscle strength. Conclusions: Magnesium significantly reduced the shivering threshold; however, due to the modest absolute reduction, this finding is considered to be clinically unimportant for induction of therapeutic hypothermia. PMID:15749735

  8. 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

  9. Chondroitin sulfate

    MedlinePlus

    ... in combination with glucosamine sulfate, shark cartilage, and camphor. Some people also inject chondroitin sulfate into the ... in combination with glucosamine sulfate, shark cartilage, and camphor seems to reduce arthritis symptoms. However, any symptom ...

  10. 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.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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...

  16. 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...

  17. Complete Genome Sequence of the Piezophilic, Mesophilic, Sulfate-Reducing Bacterium Desulfovibrio hydrothermalis AM13T

    PubMed Central

    Ji, Boyang; Gimenez, Gregory; Barbe, Valérie; Vacherie, Benoît; Rouy, Zoé; Amrani, Amira; Fardeau, Marie-Laure; Bertin, Philippe; Alazard, Didier; Leroy, Sabine; Talla, Emmanuel; Ollivier, Bernard; Dolla, Alain

    2013-01-01

    Desulfovibrio hydrothermalis AM13T is a piezophilic, mesophilic, hydrogenotrophic sulfate-reducing bacterium collected from a deep-sea hydrothermal chimney on the East Pacific Rise (2,600 m depth, 13°N). We report the genome sequence of this bacterium, which includes a 3,702,934-bp chromosome and a circular plasmid of 5,328 bp. PMID:23469349

  18. Complete Genome Sequence of the Piezophilic, Mesophilic, Sulfate-Reducing Bacterium Desulfovibrio hydrothermalis AM13(T.).

    PubMed

    Ji, Boyang; Gimenez, Gregory; Barbe, Valérie; Vacherie, Benoît; Rouy, Zoé; Amrani, Amira; Fardeau, Marie-Laure; Bertin, Philippe; Alazard, Didier; Leroy, Sabine; Talla, Emmanuel; Ollivier, Bernard; Dolla, Alain; Pradel, Nathalie

    2013-01-01

    Desulfovibrio hydrothermalis AM13(T) is a piezophilic, mesophilic, hydrogenotrophic sulfate-reducing bacterium collected from a deep-sea hydrothermal chimney on the East Pacific Rise (2,600 m depth, 13°N). We report the genome sequence of this bacterium, which includes a 3,702,934-bp chromosome and a circular plasmid of 5,328 bp. PMID:23469349

  19. 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...

  20. 34S/ 32S fractionation by sulfate-reducing microbial communities in estuarine sediments

    NASA Astrophysics Data System (ADS)

    Stam, Marjolijn C.; Mason, Paul R. D.; Laverman, Anniet M.; Pallud, Céline; Cappellen, Philippe Van

    2011-07-01

    Sulfur isotope fractionation during microbial sulfate reduction in brackish estuarine sediments was studied using an experimental flow-through reactor approach designed to preserve the in situ physical, geochemical and microbial structure of the sediment. Concurrent measurements of potential sulfate reduction rates and 34S/ 32S fractionations were carried out using intact sediment slices (2 cm thick, 4.2 cm diameter) from unvegetated, intertidal sites adjoining a salt marsh along the Scheldt estuary, The Netherlands. A total of 30 reactor experiments were performed with sediments collected in February, May and October 2006. The effects of incubation temperature (10, 20, 30 and 50 °C) and sediment depth (0-2, 4-6 and 8-10 cm) were investigated. Sulfate was supplied in non-limiting concentrations via the reactor inflow solutions; no external electron donor was supplied. Isotope fractionations ( ɛ values) were calculated from the measured differences in sulfate δ 34S between in- and outflow solutions of the reactors, under quasi-steady state conditions. Potential sulfate reduction rates (SRR) varied over one order of magnitude (5-49 nmol cm -3 h -1) and were highest in the 30 °C incubations. They decreased systematically with depth, and were highest in the sediments collected closest to the vegetated marsh. Isotope fractionations ranged from 9‰ to 34‰ and correlated inversely with SRR, as predicted by the standard fractionation model for enzymatic sulfate reduction of Rees (1973). The ɛ versus SRR relationship, however, varied between sampling times, with higher ɛ values measured in February, at comparable SRRs, than in May and October. The observed ɛ versus SRR relationships also deviated from the previously reported inverse trend for sediments collected in a marine lagoon in Denmark ( Canfield, 2001b). Thus, isotope fractionation during sulfate reduction is not uniquely determined by SRR, but is site- and time-dependent. Factors that may affect the ɛ versus SRR relationship include the structure and size of the sulfate-reducing community, and the nature and accessibility of organic substrates. Whole-sediment data such as those presented here provide a link between isotopic fractionations measured with pure cultures of sulfate-reducing prokaryotes and sulfur isotopic signatures recorded in sedimentary deposits.

  1. 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

  2. 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

  3. Sulfate-reducing anaerobic ammonium oxidation as a potential treatment method for high nitrogen-content wastewater.

    PubMed

    Rikmann, Ergo; Zekker, Ivar; Tomingas, Martin; Tenno, Taavo; Menert, Anne; Loorits, Liis; Tenno, Toomas

    2012-07-01

    After sulfate-reducing ammonium oxidation (SRAO) was first assumed in 2001, several works have been published describing this process in laboratory-scale bioreactors or occurring in the nature. In this paper, the SRAO process was performed using reject water as a substrate for microorganisms and a source of NH(4) (+), with SO(4) (2-) being added as an electron acceptor. At a moderate temperature of 20°C in a moving bed biofilm reactor (MBBR) sulfate reduction along with ammonium oxidation were established. In an upflow anaerobic sludge blanket reactor (UASBR) the SRAO process took place at 36°C. Average volumetric TN removal rates of 0.03 kg-N/m³/day in the MBBR and 0.04 kg-N/m³/day in the UASBR were achieved, with long-term moderate average removal efficiencies, respectively. Uncultured bacteria clone P4 and uncultured planctomycete clone Amx-PAn30 were detected from the biofilm of the MBBR, from sludge of the UASBR uncultured Verrucomicrobiales bacterium clone De2102 and Uncultured bacterium clone ATB-KS-1929 were found also. The stoichiometrical ratio of NH(4) (+) removal was significantly higher than could be expected from the extent of SO(4) (2-) reduction. This phenomenon can primarily be attributed to complex interactions between nitrogen and sulfur compounds and organic matter present in the wastewater. The high NH(4) (+) removal ratio can be attributed to sulfur-utilizing denitrification/denitritation providing the evidence that SRAO is occurring independently and is not a result of sulfate reduction and anammox. HCO(3) (-) concentrations exceeding 1,000 mg/l were found to have an inhibiting effect on the SRAO process. Small amounts of hydrazine were naturally present in the reaction medium, indicating occurrence of the anammox process. Injections of anammox intermediates, hydrazine and hydroxylamine, had a positive effect on SRAO process performance, particularly in the case of the UASBR. PMID:22205544

  4. Cometabolic Transformation and Cleavage of Nitrodiphenylamines by Three Newly Isolated Sulfate-Reducing Bacterial Strains

    PubMed Central

    Drzyzga, O.; Schmidt, A.; Blotevogel, K.

    1996-01-01

    Three sulfate-reducing bacterial strains (Desulfovibrio sp. strain SHV, Desulfococcus sp. strain WHC, and Desulfomicrobium sp. strain WHB) with the capacity to cometabolize 2-nitrodiphenylamine, 4-nitrodiphenylamine, and 2,4-dinitrodiphenylamine were newly isolated. Before breaking down the diphenylamine structure, these strains cometabolically reduce the nitrodiphenylamines to the corresponding aminodiphenylamines during anaerobic oxidation of the growth substrate lactate (Desulfovibrio strain SHV and Desulfomicrobium strain WHC) or benzoate (Desulfococcus strain WHB), leading to the formation of aniline and a smaller quantity of methylaniline. These compounds were not further metabolized by the sulfate reducers. The anaerobic metabolism of aminodiphenylamines also led to the formation of heterocyclic condensation products such as phenazine and acridine derivatives, provided that they contained an amino group in the ortho position of the diphenylamine (e.g., 2-aminodiphenylamine or 2,4-diaminodiphenylamine). In addition, low levels of indole and benzothiazole derivatives were identified, but these also were not further metabolized by the three sulfate-reducing strains. PMID:16535317

  5. 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.

  6. 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

  7. 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

  8. 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 within energy starved subsurface environments. An additional explanation is that diversity may be more conservative over long time scales due to consistent, basic geochemical requirements for SRB metabolic activity. This study will be expanded to include additional SRB sequences collected using similar methods to avoid potential procedural biases.

  9. 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

  10. Salt-tolerant and high-pH-resistant hydrogenase from the haloalkaliphilic, sulfate-reducing bacterium Desulfonatronum thiodismutans

    NASA Astrophysics Data System (ADS)

    Detkova, Ekaterina N.; Pikuta, Elena V.; Hoover, Richard B.

    2004-11-01

    Hydrogenase is the key enzyme of energetic metabolism in cells, catalyzing the converse reaction of hydrogen oxidation and responsible for the consumption and excretion of hydrogen in bacteria. Hydrogenases are proteins, most of which contain either nickel and iron or iron alone in their active center. Hydrogenases have been found in many microorganisms, such as methanogenic, acetogenic, nitrogen-fixing, sulfate-reducing, photosynthetic bacteria, and algae that use the hydrogen as an energy source or as an electron sink. Hydrogenases are the subject of wide physiological, biochemical, physico-chemical and genetic studies due to their abilities to produce molecular hydrogen as an alternative source of energy. Despite the large quantity of work dealing with the intracellular and extracellular enzymes of halophilic bacteria, the data about the response of hydrogenases to salts are practically absent. The study of hydrogenase in cell-free extracts of the extremely halophilic eubacterium Acetohalobium arabaticum showed a dramatic increase in the activity of the enzyme at high concentrations of NaCl and KCl (near saturated solutions). Here we present data about hydrogenase in a free-cell extract from the new halo-alkaliphilic sulfate-reducing bacterium Desulfonatronum thiodismutans, which grows on a highly mineralized carbonate-bicarbonate medium in the salinity range from 1 to 7 % NaCl and at pH 8.0-10.0. The studied enzyme was active in concentration range from 0.0 to 4.3 M NaCl with the optimum at 1.0 M NaCl. At 1.0 M NaCl the enzyme expressed 20 % additional activity, with NaCl concentration changing from 2.1 M to 3.4 M, and then the activity decreased and reached a constant level. Although sodium bicarbonate decreases the hydrogenase activity, the enzyme still showed activity at 60 % of the maximum level at concentration in a near saturated solution (1.2 M NaHCO3). The maximum enzyme activity was observed at pH 9.5 with limits of 7.5 and 11.5, which is practically equal to the pH optimum of bacterial growth. Therefore the hydrogenase of D. thiodismutans is extremely tolerant to high concentrations of sodium salts and resistant to high pH, which makes it a unique subject for biochemical research with the possibility of important biotechnological applications.

  11. 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 high pH that make it the unique subject for different biochemical research and detects the possibility for biotechnological application.

  12. 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

  13. 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.

  14. 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 degradation (DIC production), both of which support the supply of methanogenic substrates. A negative correlation between methanogenesis rates and dissolved oxygen in the bottom-near water was not obvious; however, anoxic conditions within the OMZ might be advantageous for methanogenic organisms at the sediment-water interface.

    Our results revealed a high relevance of surface methanogenesis on the shelf, where the ratio between surface to deep (below sulfate penetration) methanogenic activity ranged between 0.13 and 105. In addition, methane concentration profiles indicated a partial release of surface methane into the water column as well as consumption of methane by anaerobic methane oxidation (AOM) in the surface sediment. The present study suggests that surface methanogenesis might play a greater role in benthic methane budgeting than previously thought, especially for fueling AOM above the sulfate-methane transition zone.

  15. 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), both of which support the supply of methanogenic substrates. A negative correlation of methanogenesis rates with dissolved oxygen in the bottom-near water was not obvious, however, anoxic conditions within the OMZ might be advantageous for methanogenic organisms at the sediment-water interface. Our results revealed a high relevance of surface methanogenesis on the shelf, where the ratio between surface to deep (below sulfate penetration) methanogenic activity ranged between 0.13 and 105. In addition, methane concentration profiles indicate a partial release of surface methane into the water column as well as a partial consumption of methane by anaerobic methane oxidation (AOM) in the surface sediment. The present study suggests that surface methanogenesis might play a greater role in benthic methane budgeting than previously thought, especially for fueling AOM above the sulfate-methane transition zone.

  16. 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 limiting the mobility of uranium in the presence of dissolved and/or solid-phase oxidants. The results of this field study confirmed those of previous laboratory studies which suggested that reoxidation of uranium under nitrate-reducing conditions can be substantially limited by preferential oxidation of reduced sulfur-bearing species. PMID:26897652

  17. 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 limiting the mobility of uranium in the presence of dissolved and/or solid-phase oxidants. The results of this field study confirmed those of previous laboratory studies which suggested that reoxidation of uranium under nitrate-reducing conditions can be substantially limited by preferential oxidation of reduced sulfur-bearing species.

  18. Activity and community structures of sulfate-reducing microorganisms in polar, temperate and tropical marine sediments.

    PubMed

    Robador, Alberto; Müller, Albert L; Sawicka, Joanna E; Berry, David; Hubert, Casey R J; Loy, Alexander; Jørgensen, Bo Barker; Brüchert, Volker

    2016-04-01

    Temperature has a fundamental impact on the metabolic rates of microorganisms and strongly influences microbial ecology and biogeochemical cycling in the environment. In this study, we examined the catabolic temperature response of natural communities of sulfate-reducing microorganisms (SRM) in polar, temperate and tropical marine sediments. In short-term sediment incubation experiments with (35)S-sulfate, we demonstrated how the cardinal temperatures for sulfate reduction correlate with mean annual sediment temperatures, indicating specific thermal adaptations of the dominant SRM in each of the investigated ecosystems. The community structure of putative SRM in the sediments, as revealed by pyrosequencing of bacterial 16S rRNA gene amplicons and phylogenetic assignment to known SRM taxa, consistently correlated with in situ temperatures, but not with sediment organic carbon concentrations or C:N ratios of organic matter. Additionally, several species-level SRM phylotypes of the class Deltaproteobacteria tended to co-occur at sites with similar mean annual temperatures, regardless of geographic distance. The observed temperature adaptations of SRM imply that environmental temperature is a major controlling variable for physiological selection and ecological and evolutionary differentiation of microbial communities. PMID:26359912

  19. 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.

  20. Microarray and Functional Gene Analyses of Sulfate-Reducing Prokaryotes in Low-Sulfate, Acidic Fens Reveal Cooccurrence of Recognized Genera and Novel Lineages

    PubMed Central

    Loy, Alexander; Ksel, Kirsten; Lehner, Angelika; Drake, Harold L.; Wagner, Michael

    2004-01-01

    Low-sulfate, acidic (approximately pH 4) fens in the Lehstenbach catchment in the Fichtelgebirge mountains in Germany are unusual habitats for sulfate-reducing prokaryotes (SRPs) that have been postulated to facilitate the retention of sulfur and protons in these ecosystems. Despite the low in situ availability of sulfate (concentration in the soil solution, 20 to 200 ?M) and the acidic conditions (soil and soil solution pHs, approximately 4 and 5, respectively), the upper peat layers of the soils from two fens (Schlppnerbrunnen I and II) of this catchment displayed significant sulfate-reducing capacities. 16S rRNA gene-based oligonucleotide microarray analyses revealed stable diversity patterns for recognized SRPs in the upper 30 cm of both fens. Members of the family Syntrophobacteraceae were detected in both fens, while signals specific for the genus Desulfomonile were observed only in soils from Schlppnerbrunnen I. These results were confirmed and extended by comparative analyses of environmentally retrieved 16S rRNA and dissimilatory (bi)sulfite reductase (dsrAB) gene sequences; dsrAB sequences from Desulfobacca-like SRPs, which were not identified by microarray analysis, were obtained from both fens. Hypotheses concerning the ecophysiological role of these three SRP groups in the fens were formulated based on the known physiological properties of their cultured relatives. In addition to these recognized SRP lineages, six novel dsrAB types that were phylogenetically unrelated to all known SRPs were detected in the fens. These dsrAB sequences had no features indicative of pseudogenes and likely represent novel, deeply branching, sulfate- or sulfite-reducing prokaryotes that are specialized colonists of low-sulfate habitats. PMID:15574893

  1. [NO3-/NO2- inhibits sulfate-reducing activity of the enrichment culture of sulfate-reducing prokaryotes from an off-shore oil reservoir at Bohai Bay, China].

    PubMed

    Liu, Hong-Yu; Shi, Rong-Jiu; Zhang, Ying; Shi, Zhen-Guo; Zhang, Ying-Yue; Yu, Liang; Zhang, Xiao-Bo; Tan, Tao

    2014-08-01

    Long-term injection of sulfate-rich water into oil reservoirs stimulates the proliferation of sulfate-reducing prokaryotes (SRP) therein and results in production of a great amount of H2S, leading to souring in oil reservoirs and related environmental problems. In this study, we first, using modified API RP 38 medium, enriched SRP present in production water from a producing well at Bohai Bay, China, and then examined the inhibitory effects of nitrate or nitrite on sulfate reduction activity of the SRP. Results showed that the enriched SRP culture exhibited a high sulfate reduction activity as indicated by a sulfate-reducing rate of 10.4 mmol SO4(2-) x d(-1) x g(-1) dry cell. In presence of 0.4, 0.8, 1.8, and 4.2 mmol x L(-1) nitrate, sulfate reduction was inhibited for 5, 9, 20, and over 35 days, respectively. With the addition of 0.6, 0.9, 1.4, 2.6 and 4.6 mmol x L(-1) of nitrite, the inhibitory period lasted 3, 12, 22, and over 39 days, respectively. The SRP enrichment culture could dissimilatorily reduce nitrate to ammonium. When sulfate, nitrate and nitrite coexisted, nitrate or nitrite was preferentially used over sulfate as electron acceptor by the enriched SRP. This competitive use of electron acceptor and the strong inhibitory effect of nitrite possibly accounted for the suppression of nitrate and nitrite on the sulfate-reducing activity of the enriched SRP cultures from offshore oil reservoir at Bohai Bay. PMID:25509091

  2. [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

  3. 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

  4. 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

  5. In-Situ Survival Mechanisms of U and Tc Reducing Bacteria in Contaminated Sediments Final Report

    SciTech Connect

    Lee Krumholz Jimmy Ballard

    2005-07-11

    The proposed effort will identify genes and ultimately physiological mechanisms and pathways that are expressed under in situ conditions and are critical to functioning of aquifer dwelling anaerobic bacteria living in contaminated systems. The main objectives are: (1) Determine which Metal-reducer specific genes are important for activities in normal and contaminated subsurface sediment. To achieve these goals, we have generated a library of chromosomal mutants. These are introduced into contaminated sediments, incubated, allowed to grow, and then reisolated. A negative selection process allows us to determine which mutants have been selected against in sediments and thereby identify genes required for survival in subsurface sediments. (2) Delineate the function of these genes through GeneBank and Clusters of Orthologous Groups (COGs) comparisons and analyze other sediment microorganisms to determine if similar genes are present in these populations. After determining the sequence of the genes identified through the previous objectives, we delineate the role of those specific genes in the physiology of G20, MR-1 and perhaps other microorganisms. (3) Determine the loss in function of a select group of mutants. Cells with mutations in known genes with testable functions are assayed for the loss of that function if specific assays are available. Mutants with unknown loss of function and other mutants are run through a series of tests including motility, attachment, and rate of sulfate or iron reduction. These tests allow us to categorize mutants for subsequent more detailed study.

  6. The First Genomic and Proteomic Characterization of a Deep-Sea Sulfate Reducer: Insights into the Piezophilic Lifestyle of Desulfovibrio piezophilus

    PubMed Central

    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 C1TLV30T 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

  7. 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

  8. Anaerobic degradation of m-cresol in anoxic aquifer slurries: Carboxylation reactions in a sulfate-reducing bacterial enrichment

    SciTech Connect

    Ramanand, K.; Suflita, J.M. )

    1991-06-01

    The anaerobic biodegradation of m-cresol was observed in anoxic aquifer slurries kept under both sulfate-reducing and nitrate-reducing but not methanogenic conditions. More than 85% of the parent substrate (300 {mu}M) was consumed in less than 6 days in slurries kept under the former two conditions. No appreciable loss of the compound from the corresponding autoclaved controls was measurable. A bacterial consortium was enriched from the slurries for its ability to metabolize m-cresol under sulfate-reducing conditions. Metabolism in this enrichment culture was inhibited in the presence of oxygen or molybdate (500{mu}M) and in the absence of sulfate but was unaffected by bromoethanesulfanic acid. The consortium consumed 3.63 mol of sulfate per mol of m-cresol degraded. This stoichiometry is about 87% of that theoretically expected and suggests that m-cresol was largely mineralized. Resting-cell experiments demonstrated that the degradation of m-cresol proceeded only in the presence of bicarbonate. 4-Hydroxy-2-methylbenzoic acid and acetate were detected as transient intermediates. Thus, the parent substrate was initially carboxylated as the primary degradative event. The sulfate-reducing consortium could also decarboxylate p- but not m-hydroxybenzoate to near stoichiometric amounts of phenol, but this reaction was not sulfate dependent. The presence of p-hydroxybenzoate in the medium temporarily inhibits m-cresol metabolism such that the former compound was metabolized prior to the latter and phenol was degraded in a sequential manner.

  9. 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.

  10. 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.

  11. 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.

  12. Molecular evidence for lignin degradation in sulfate-reducing mangrove sediments (Amazônia, Brazil)

    NASA Astrophysics Data System (ADS)

    Dittmar, Thorsten; Lara, Rubén José

    2001-05-01

    - Molecular lignin analyses have become a powerful quantitative approach for estimating flux and fate of vascular plant organic matter in coastal and marine environments. The use of a specific molecular biomarker requires detailed knowledge of its decomposition rates relative to the associated organic matter and its structural diagenetic changes. To gain insight into the poorly known processes of anaerobic lignin diagenesis, molecular analyses were performed in the sulfate-reducing sediment of a north Brazilian mangrove. Organic matter in samples representing different diagenetic stages (i.e., fresh litter, a sediment core, and percolating water) was characterized by alkaline CuO oxidation for lignin composition, element (C, N), and stable carbon isotope analyses. On the basis of these results and on a balance model, long-term in situ decomposition rates of lignin in sulfate-reducing sediments were estimated for the first time. The half-life ( T1/2) of lignin derived from mangrove leaf litter (mainly Rhizophora mangle) was ˜150 yr in the upper 1.5 m of the sediment. Associated organic carbon from leaf tissue was depleted to ˜75% within weeks, followed by a slow mineralization in the sediment ( T1/2 ≈ 300 yr). Unlike the known pathways of lignin diagenesis, even highly degraded lignin did not show any alterations of the propyl or methoxyl side chains, as evident from stable acid to aldehyde ratios and the proportion of methoxylated phenols (vanillyl and syringyl phenols). Aromatic ring cleavage is probably the principal mechanism for lignin decay in the studied environment. Cinnamyl phenols were highly abundant in mangrove leaves and were rapidly depleted during early diagenesis. Thus, the cinnamyl to vanillyl ratio could be used as a tracer for early diagenesis even under the sulfate-reducing conditions. Syringyl phenols were removed from dissolved organic matter in interstitial water, probably by sorption onto the sediment. Suspended organic matter in a mangrove creek showed a different lignin signature than its source, namely sedimentary organic matter or mangrove litter, with clear evidence for propyl side chain oxidation. This was probably attributable to erosion of aerated thin sediment surface layers during mangrove inundation. Although particulate and dissolved organic matter in the mangrove creek have a common source, their compositional patterns were different, because of different pathways of release, degradation, and transport to the creek.

  13. Sensitization of Colicin K-Treated Bacteria By Sodium Dodecyl Sulfate: Presence of Free Colicin in Colicin K-Treated Cultures of Escherichia coli

    PubMed Central

    Cavard, Danièle

    1976-01-01

    A method of assaying colicin K is described. It makes use of two properties of sodium dodecyl sulfate to protect bacteria against colicin action and to dissolve those bacteria on which colicin K had started its action. By this method, the kinetics of bacterial killing by colicin K have been measured directly in the treated culture without intervening dilution. The kinetics are exponential with time and are a function of the colicin multiplicity, as described previously, but do not reach a final plateau. At any time during colicin treatment, free colicin is found in the medium. Procedures that eliminate or destroy this free colicin, such as centrifugation and resuspension of the treated bacteria in a fresh medium, or addition of trypsin or sodium dodecyl sulfate to the treated culture stop bacterial killing. PMID:773302

  14. Ambient iron concentration regulates the sulfate reducing activity in the mangrove swamps of Diwar, Goa, India

    NASA Astrophysics Data System (ADS)

    Attri, Kuldeep; Kerkar, Savita; LokaBharathi, P. A.

    2011-11-01

    In order to test the hypothesis that the ambient iron concentrations could regulate sulfate reducing activity (SRA) in mangrove areas, 10 cm cores were examined from test and reference sites. The test site at Diwar mangrove ecosystem is highly influenced by iron released by the movement of barges carrying iron ore during the non-monsoon seasons and the reference site at Tuvem is relatively pristine. The average iron concentrations were 17.9% (±8.06) at Diwar and 6.3% (±1.5) at Tuvem. Sulfate reducing rates (SRR) ranged from 50.21 to 698.66 nM cm -3 d -1 at Tuvem, and from 23.32 to 294.49 nM cm -3d -1 in Diwar. Pearson's correlation coefficients between SRR and environmental parameters showed that at Tuvem, the SRR was controlled by SO 4-2 ( r = 0.498, p < 0.001, n = 60) more than organic carbon ( r = 0.316 p < 0.05, n = 60). At Diwar, the SRR was governed by the iron concentrations at an r-value of -0.761 ( p < 0.001, n = 60), suggesting that ca.58% of the variation in SRR was influenced negatively by variations in ambient iron concentrations. This influence was more than the positive influence of TOC ( r = 0.615, p < 0.001, n = 60). Laboratory experiments to check the influence of iron on SRR also supported our field observations. At an experimental manipulation of 50 ppm Fe 3+ there was an increase in SRR but at 100 ppm an inhibitory effect was observed. At 1000 ppm Fe 3+ there was a decrease in the SRR up to 93% of the control. Thus, our study showed that ambient iron concentrations influence SRR negatively at Diwar and counters the positive influence of organic carbon. Consequently, the influence could cascade to other biogeochemical processes in these mangrove swamps, especially the mineralization of organic matter to carbon dioxide by sulfate respiration.

  15. 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.

  16. 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.

  17. 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)).

  18. 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

  19. Molecular survey of sulphate-reducing bacteria in the deep-sea sediments of the west Pacific Warm Pool

    NASA Astrophysics Data System (ADS)

    Wang, Peng; Xiao, Xiang; Zhang, Haiyan; Wang, Fengping

    2008-08-01

    The sulfate-reducing bacteria (SRB) community in the deep-sea sediments of the west Pacific Warm Pool (WP) was surveyed by molecular phylogenetic analyses using primers targeting the 16S rRNA gene fragments of SRB. Specific 16S rRNA gene libraries from five sediment layers (1-cm, 3-cm, 6-cm, 10-cm and 12-cm layer) of the 12-cm core of WP-0 were constructed. The clones in the five libraries were differentiated by restriction fragment length polymorphism (RFLP) and representative clones were selected to sequence. It was found that the clones fell into four groups, which were closest related to Desulfotomaculum, Desulfacinum, Desulfomonile and Desulfanuticus. Desulfacinum-like clones were only detected in the upper layers of the sediment core, whereas Desulfomonile-like clones were only present in the deeper layers. Fluorescence in situ hybridization (FISH) was further carried out to visualize and count the SRB and bacteria in the five sediment layers. It was found that SRB constituted only a small proportion of the bacteria community (0.34% 1.95%), it had the highest content in the 3-cm layer (1.95%) and had a depth-related decreasing tendency along the 12-cm core.

  20. Epithermal neutron activation analysis of Cr(VI)-reducer basalt-inhabiting bacteria.

    PubMed

    Tsibakhashvili, Nelly Yasonovna; Frontasyeva, Marina Vladimirovna; Kirkesali, Elena Ivanovna; Aksenova, Nadezhda Gennadievna; Kalabegishvili, Tamaz Levanovich; Murusidze, Ivana Georgievich; Mosulishvili, Ligury Mikhailovich; Holman, Hoi-Ying N

    2006-09-15

    Epithermal neutron activation analysis (ENAA) has been applied to study elemental composition of Cr(VI)-reducer bacteria isolated from polluted basalts from the Republic of Georgia. Cr(VI)-reducing ability of the bacteria was examined by electron spin resonance, demonstrating that the bacteria differ in their rates of Cr(VI) reduction. A well-pronounced correlation between the ability of the bacteria to accumulate Cr(V) and their ability to reduce Cr(V) to Cr(III) observed in our experiments is discussed. Elemental analysis of these bacteria also revealed that basalt-inhabiting bacteria are distinguished by relative contents of essential elements such as K, Na, Mg, Fe, Mn, Zn, and Co. A high rate of Cr(III) formation correlates with a high concentration of Co in the bacterium. ENAA detected some similarity in the elemental composition of the bacteria. The relatively high contents of Fe detected in the bacteria (140-340 microg/g of dry weight) indicate bacterial adaptation to the environmental conditions typical of the basalts. The concentrations of at least 12-19 different elements were determined in each type of bacteria simultaneously starting with the major to ultratrace elements. The range of concentrations spans over 8 orders of magnitude. PMID:16970299

  1. 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

  2. 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...

  3. 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

  4. 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

  5. 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

  6. Draft Genome Sequence of Desulfitobacterium hafniense Strain DH, a Sulfate-Reducing Bacterium Isolated from Paddy Soils.

    PubMed

    Zhang, Xi; Li, Guo-Xiang; Chen, Song-Can; Jia, Xiao-Yu; Wu, Kun; Cao, Chang-Li; Bao, Peng

    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

  7. 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

  8. Complete oxidation of toluene under strictly anoxic conditions by a new sulfate-reducing bacterium.

    PubMed Central

    Rabus, R; Nordhaus, R; Ludwig, W; Widdel, F

    1993-01-01

    A toluene-degrading sulfate-reducing bacterium, strain Tol2, was isolated from marine sediment under strictly anoxic conditions. Toluene was toxic if applied directly to the medium at concentrations higher than 0.5 mM. To provide toluene continuously at a nontoxic concentration, it was supplied in an inert hydrophobic carrier phase. The isolate had oval, sometimes motile cells (1.2 to 1.4 by 1.2 to 2.0 microns). The doubling time was 27 h. Toluene was completely oxidized to CO2, as demonstrated by measurement of the degradation balance. The presence of carbon monoxide dehydrogenase and formate dehydrogenase indicated a terminal oxidation of acetyl coenzyme A via the CO dehydrogenase pathway. The use of hypothetical intermediates of toluene degradation was tested in growth experiments and adaptation studies with dense cell suspensions. Results do not support a degradation of toluene via one of the cresols or methylbenzoates, benzyl alcohol, or phenylacetate as free intermediate. Benzyl alcohol did not serve as growth substrate; moreover, it was a strong, specific inhibitor of toluene degradation, whereas benzoate utilization was not affected by benzyl alcohol. Sequencing of 16S rRNA revealed a relationship to the metabolically dissimilar genus Desulfobacter and on a deeper level to the genus Desulfobacterium. The new genus and species Desulfobacula toluolica is proposed. Images PMID:7686000

  9. [Evaluation of molybdate and nitrate on sulphate-reducing bacteria related to corrosion processes in industrial systems].

    PubMed

    Torrado Rincón, J R; Calixto Gómez, D M; Sarmiento Caraballo, A E; Panqueva Alvarez, J H

    2008-01-01

    The sulfate-reducing bacteria growth kinetics and the biotransformation of sulfate into hydrogen sulfide were studied under laboratory conditions, using batch and continuous assays to determine the effect of molybdate and nitrate as metabolic inhibitors. The microorganisms were isolated from water coming from a natural gas dehydration plant, where they were associated with Microbiologically Influenced Corrosion (MIC) processes, and later cultured in planktonic and sessile states. The addition of 5 mM molybdate showed a growth reduction to levels of non-detectable floating cells and a six order of magnitude reduction in biofilms, concomitant with a sulfide decrease of around 100% in all cultures inhibited by this compound. The addition of 75 mM nitrate showed a four order of magnitude reduction in free bacterial cells and a two order of magnitude reduction in adhered bacterial cells, respectively, as well as a sulfide decrease of around 80%. The decreased corrosion rate detected suggests that these inorganic salts could be non-conventional biocides for an effective and environmentally non contaminant way of controlling and mitigating internal biocorrosion processes in storage tanks and pipelines in natural gas and petroleum industrial systems. PMID:18669055

  10. 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 saline), but it was more significant in groups G and L. Moreover, Hypotension was higher in groups S and G and it was lessened in group P. PMID:24829787

  11. 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...

  12. Amending poultry litter to reduce ammonia producing bacteria

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Poultry litter is a valuable nutrient source for crop production that requires proper management to garner environmentally and financially sustainable benefits. Successful management to reduce ammonia (NH3-N) and its harmful side-effects for poultry and the environment can be aided by the use of lit...

  13. 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

  14. Activity and phylogenetic diversity of sulfate-reducing microorganisms in low-temperature subsurface fluids within the upper oceanic crust.

    PubMed

    Robador, Alberto; Jungbluth, Sean P; LaRowe, Douglas E; Bowers, Robert M; Rappé, Michael S; Amend, Jan P; Cowen, James P

    2014-01-01

    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 (35)S-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

  15. 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

  16. 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.

  17. 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 ...

  18. 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 ...

  19. 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...

  20. Guanine Plus Cytosine Contents of the Deoxyribonucleic Acids of Some Sulfate-Reducing Bacteria: a Reassessment

    PubMed Central

    Skyring, G. W.; Jones, H. E.

    1972-01-01

    Guanine plus cytosine (GC) contents of the deoxyribonucleic acids of Desulfovibrio and Desulfotomaculum have been used as a basis for classification. Some of these data have been incorrectly calculated, resulting in errors of as much as 5% GC. This situation has been corrected by a reanalysis of existing data and by the contribution of new data. PMID:5011245

  1. 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.

  2. INNOVATIVE, IN SITU TREATMENT OF ACID MINE DRAINAGE USING SULFATE REDUCING BACTERIA

    EPA Science Inventory

    Acid generation in abandoned mines is a widespread problem. There are a numberous quantity of abandoned mines in the west which have no power source, have limited physical accessibility and have limited remediation funds available. Acid is produced chemically, through pyritic min...

  3. 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.

  4. Transformation of non-oxygenated, homocyclic aromatic compounds by aquifer microorganisms under methanogenic and sulfate-reducing conditions

    SciTech Connect

    Edwards, E.A.

    1993-01-01

    A mixed methanogenic culture was enriched from creosote-contaminated sediment that used toluene or o-xylene as sole source of carbon and energy. The adaptation periods before the onset of measurable degradation were long (120-255 days). Both toluene and o-xylene were completely degraded to stoichiometric amounts of methane, carbon dioxide and biomass. The enriched methanogenic cultures could not degrade benzene, m-xylene, p-xylene or ethylbenzene. The doubling times were 6 days and 10 days for the cultures growing on toluene or o-xylene, respectively. Toluene and o-xylene were toxic and inhibited degradation as initial concentrations increased. The presence of preferred substrates including glucose, methanol, and acetate inhibited toluene degradation. Isotope trapping and simultaneous adaptation experiments provided evidence that toluene was degraded via both methyl and ring hydroxylation. A mixed sulfate-reducing culture was enriched from gasoline-contaminated sediment that used toluene and all three isomers of xylene as sole sources of carbon and energy. The adaptation period before the onset of measurable degradation by the sulfate-reducing cultures was followed sequentially by m-, p-, and o-xylene. The doubling time for the sulfate-reducing cultures growing on toluene or xylenes was about 20 days. The build up of sulfide as a result of sulfate-reduction appeared to inhibit degradation. Benzoate was detected as a transient intermediate and benzylsuccinate accumulated in sulfate-reducing cultures fed toluene. Benzene degradation was not initially observed. However, after all other carbon sources were exhausted benzene was eventually completely mineralized to carbon dioxide under strictly anaerobic conditions. The rates of degradation were very slow, and were influenced by the initial benzene concentration and by the presence of other carbon sources that could be degraded preferentially over benzene.

  5. Isolation and preliminary characterization of a soluble nitrate reductase from the sulfate reducing organism Desulfovibrio desulfuricans ATCC 27774.

    PubMed

    Bursakov, S; Liu, M Y; Payne, W J; LeGall, J; Moura, I; Moura, J J

    1995-02-01

    Desulfovibrio desulfuricans ATCC 27774 is a sulfate reducer that can adapt to nitrate respiration, inducing the enzymes required to utilize this alternative metabolic pathway. Nitrite reductase from this organism has been previously isolated and characterized, but no information was available on the enzyme involved in the reduction of nitrate. This is the first report of purification to homogeneity of a nitrate reductase from a sulfate reducing organism, thus completing the enzymatic system required to convert nitrate (through nitrite) to ammonia. D. desulfuricans nitrate reductase is a monomeric (circa 70 kDa) periplasmic enzyme with a specific activity of 5.4 K(m) for nitrate was estimated to be 20 microM. EPR signals due to one [4Fe-4S] cluster and Mo(V) were identified in dithionite reduced samples and in the presence of nitrate. PMID:16887508

  6. 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

  7. Changing microspatial patterns of sulfate-reducing microorganisms (SRM) during cycling of marine stromatolite mats.

    PubMed

    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

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. 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.

  13. Methylmercury decomposition in sediments and bacterial cultures: Involvement of methanogens and sulfate reducers in oxidative demethylation

    SciTech Connect

    Oremland, R.S.; Culbertson, C.W. ); Winfrey, M.R. )

    1991-01-01

    The biogeochemical cycling of mercury has received considerable attention because of the toxicity of methylmercury, its bioaccumulation in biota, and its biomagnification in aquatic food chains. The formation of methylmercury is mediated primarily by microorganisms. Demethylation of monomethylmercury in freshwater and estuarine sediments and in bacterial cultures was investigated with {sup 14}CH{sub 3}HgI. Under anaerobiosis, results with inhibitors indicated partial involvement of both sulfate reducers and methanogens, the former dominated 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 demthylation were mainly {sup 14}CO{sub 2} as well as lesser amounts of {sup 14}CH{sub 4}. Acetogenic activity resulted in fixation of some {sup 14}CO{sub 2} produced from {sup 14}CH{sub 3}HgI into acetate. Aerobic demethylation in estuarine sediments produced only {sup 14}CH{sub 4}, while aerobic demethylation in freshwater sediments produced small amounts of both {sup 14}CH{sub 4} and {sup 14}CO{sub 2}. Two species of Desulfovibrio produced only traces of {sup 14}CH{sub 4} from {sup 14}CH{sub 3}HgI, while a culture of a methylotrophic methanogen formed traces of {sup 14}CO{sub 2} and {sup 14}CH{sub 4} when grown on trimethylamine in the presence of the {sup 14}CH{sub 3}HgI. 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. This indicates the presence of an oxidative pathway, possibly one in which methylmercury serves as an analog of one-carbon substrates.

  14. Sulfate-reducing bacterium Desulfovibrio desulfuricans ND132 as a model for understanding bacterial mercury methylation.

    PubMed

    Gilmour, Cynthia C; Elias, Dwayne A; Kucken, Amy M; Brown, Steven D; Palumbo, Anthony V; Schadt, Christopher W; Wall, Judy D

    2011-06-01

    We propose the use of Desulfovibrio desulfuricans ND132 as a model species for understanding the mechanism of microbial Hg methylation. Strain ND132 is an anaerobic dissimilatory sulfate-reducing bacterium (DSRB), isolated from estuarine mid-Chesapeake Bay sediments. It was chosen for study because of its exceptionally high rates of Hg methylation in culture and its metabolic similarity to the lost strain D. desulfuricans LS, the only organism for which methylation pathways have been partially defined. Strain ND132 is an incomplete oxidizer of short-chain fatty acids. It is capable of respiratory growth using fumarate as an electron acceptor, supporting growth without sulfide production. We used enriched stable Hg isotopes to show that ND132 simultaneously produces and degrades methylmercury (MeHg) during growth but does not produce elemental Hg. MeHg produced by cells is mainly excreted, and no MeHg is produced in spent medium. Mass balances for Hg and MeHg during the growth of cultures, including the distribution between filterable and particulate phases, illustrate how medium chemistry and growth phase dramatically affect Hg solubility and availability for methylation. The available information on Hg methylation among strains in the genus Desulfovibrio is summarized, and we present methylation rates for several previously untested species. About 50% of Desulfovibrio strains tested to date have the ability to produce MeHg. Importantly, the ability to produce MeHg is constitutive and does not confer Hg resistance. A 16S rRNA-based alignment of the genus Desulfovibrio allows the very preliminary assessment that there may be some evolutionary basis for the ability to produce MeHg within this genus. PMID:21515733

  15. Intervention to Reduce Transmission of Resistant Bacteria in Intensive Care

    PubMed Central

    Huskins, W. Charles; Huckabee, Charmaine M.; O’Grady, Naomi P.; Murray, Patrick; Kopetskie, Heather; Zimmer, Louise; Walker, Mary Ellen; Sinkowitz-Cochran, Ronda L.; Jernigan, John A.; Samore, Matthew; Wallace, Dennis; Goldmann, Donald A.

    2012-01-01

    BACKGROUND Intensive care units (ICUs) are high-risk settings for the transmission of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococcus (VRE). METHODS In a cluster-randomized trial, we evaluated the effect of surveillance for MRSA and VRE colonization and of the expanded use of barrier precautions (intervention) as compared with existing practice (control) on the incidence of MRSA or VRE colonization or infection in adult ICUs. Surveillance cultures were obtained from patients in all participating ICUs; the results were reported only to ICUs assigned to the intervention. In intervention ICUs, patients who were colonized or infected with MRSA or VRE were assigned to care with contact precautions; all the other patients were assigned to care with universal gloving until their discharge or until surveillance cultures obtained at admission were reported to be negative. RESULTS During a 6-month intervention period, there were 5434 admissions to 10 intervention ICUs, and 3705 admissions to 8 control ICUs. Patients who were colonized or infected with MRSA or VRE were assigned to barrier precautions more frequently in intervention ICUs than in control ICUs (a median of 92% of ICU days with either contact precautions or universal gloving [51% with contact precautions and 43% with universal gloving] in intervention ICUs vs. a median of 38% of ICU days with contact precautions in control ICUs, P<0.001). In intervention ICUs, health care providers used clean gloves, gowns, and hand hygiene less frequently than required for contacts with patients assigned to barrier precautions; when contact precautions were specified, gloves were used for a median of 82% of contacts, gowns for 77% of contacts, and hand hygiene after 69% of contacts, and when universal gloving was specified, gloves were used for a median of 72% of contacts and hand hygiene after 62% of contacts. The mean (±SE) ICU-level incidence of events of colonization or infection with MRSA or VRE per 1000 patient-days at risk, adjusted for baseline incidence, did not differ significantly between the intervention and control ICUs (40.4±3.3 and 35.6±3.7 in the two groups, respectively; P = 0.35). CONCLUSIONS The intervention was not effective in reducing the transmission of MRSA or VRE, although the use of barrier precautions by providers was less than what was required. (Funded by the National Institute of Allergy and Infectious Diseases and others; STAR*ICU ClinicalTrials.gov number, NCT00100386.) PMID:21488763

  16. Environmental application of nanomaterials and metal-reducing bacteria to remediate arsenic-contaminated groundwater.

    PubMed

    Sun, Eun-Young; Kim, Yumi; Park, Byungno; Roh, Yul

    2011-02-01

    The objective of this study was to remediate As-contaminated groundwater using both nanomaterials and metal-reducing bacteria. In the batch experiment, a set of Pd-akaganeite in combination with the bacteria removed 95% of the arsenic from the contaminated groundwater. This result suggested that nanotechnology and biotechnology has the potential to create novel and effective treatment technologies for arsenic-contaminated groundwater. PMID:21456243

  17. Dynamics of Bacterial Sulfate Reduction in a Eutrophic Lake

    PubMed Central

    Ingvorsen, K.; Zeikus, J. G.; Brock, T. D.

    1981-01-01

    Bacterial sulfate reduction in the surface sediment and the water column of Lake Mendota, Madison, Wis., was studied by using radioactive sulfate (35SO42−). High rates of sulfate reduction were observed at the sediment surface, where the sulfate pool (0.2 mM SO42−) had a turnover time of 10 to 24 h. Daily sulfate reduction rates in Lake Mendota sediment varied from 50 to 600 nmol of SO42− cm−3, depending on temperature and sampling date. Rates of sulfate reduction in the water column were 103 times lower than that for the surface sediment and, on an areal basis, accounted for less than 18% of the total sulfate reduction in the hypolimnion during summer stratification. Rates of bacterial sulfate reduction in the sediment were not sulfate limited at sulfate concentrations greater than 0.1 mM in short-term experiments. Although sulfate reduction seemed to be sulfate limited below 0.1 mM, Michaelis-Menten kinetics were not observed. The optimum temperature (36 to 37°C) for sulfate reduction in the sediment was considerably higher than in situ temperatures (1 to 13°C). The response of sulfate reduction to the addition of various electron donors metabolized by sulfate-reducing bacteria in pure culture was investigated. The degree of stimulation was in this order: H2 > n-butanol > n-propanol > ethanol > glucose. Acetate and lactate caused no stimulation. PMID:16345898

  18. 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 pasteurized experiment, suggesting either different populations of NRM or a population of NRM that was not resistant to the 80°C pre-treatment. These results demonstrate that thermophilic NRM exist in cold marine sediments from Aarhus Bay and can be enriched under appropriate conditions. Effective microbial control of SRM activity at high temperature in our Aarhus Bay sediment model system depends on the addition of nitrate to stimulate this group of microorganisms.

  19. High abundance and diversity of iron-reducing bacteria in wet tropical forest soils

    NASA Astrophysics Data System (ADS)

    Dubinsky, E. A.; Brodie, E. L.; Andersen, G. L.; Silver, W. L.; Firestone, M. K.

    2005-12-01

    In wet tropical forests, warm and damp conditions promote rapid oxygen consumption in soils that contain high concentrations of iron oxides. Ferric iron is often the most abundant terminal electron acceptor for bacteria in soil during frequent periods of oxygen depletion. Highly-weathered soils of the wet tropics are likely to support large populations of Fe(III) reducing microorganisms whose activity is consequential to soil mineralogy and geochemistry. We studied the diversity and abundance of Fe(III)-reducing bacteria along a 700 m elevation gradient with variable soil redox conditions in northeast Puerto Rico. Culturable iron-reducers were enumerated, isolated and identified using five different media that contained poorly-crystalline Fe(III) oxides as the terminal electron acceptor. Entire soil microbial communities were characterized along the gradient using high-density 16S rRNA gene microarrays capable of detecting 9000 different bacterial and archaeal taxa and assessing changes in their spatial abundance. Fe(III)-reducing bacteria spanned the Proteobacteria and Firmicutes and included many previously unidentified Fe(III) reducers. Populations of culturable iron reducers numbered 108 to 1010 bacteria per gram soil, some of the highest numbers found in any soils or sediments, and population size increased significantly with elevation. These bacteria were dominated by both unclassified alpha- and gamma proteobacteria not previously known to reduce iron, in addition to delta-proteobacteria, such as the family Geobacteraceae, that are well-known Fe(III) reducers. The activity of this group of bacteria can affect biogeochemical cycles that are linked to iron and fundamental to tropical forest productivity, including phosphorus and carbon cycling.

  20. 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

  1. Homology Modeling of Dissimilatory APS Reductases (AprBA) of Sulfur-Oxidizing and Sulfate-Reducing Prokaryotes

    PubMed Central

    Meyer, Birte; Kuever, Jan

    2008-01-01

    Background The dissimilatory adenosine-5′-phosphosulfate (APS) reductase (cofactors flavin adenine dinucleotide, FAD, and two [4Fe-4S] centers) catalyzes the transformation of APS to sulfite and AMP in sulfate-reducing prokaryotes (SRP); in sulfur-oxidizing bacteria (SOB) it has been suggested to operate in the reverse direction. Recently, the three-dimensional structure of the Archaeoglobus fulgidus enzyme has been determined in different catalytically relevant states providing insights into its reaction cycle. Methodology/Principal Findings Full-length AprBA sequences from 20 phylogenetically distinct SRP and SOB species were used for homology modeling. In general, the average accuracy of the calculated models was sufficiently good to allow a structural and functional comparison between the beta- and alpha-subunit structures (78.8–99.3% and 89.5–96.8% of the AprB and AprA main chain atoms, respectively, had root mean square deviations below 1 Å with respect to the template structures). Besides their overall conformity, the SRP- and SOB-derived models revealed the existence of individual adaptations at the electron-transferring AprB protein surface presumably resulting from docking to different electron donor/acceptor proteins. These structural alterations correlated with the protein phylogeny (three major phylogenetic lineages: (1) SRP including LGT-affected Archaeoglobi and SOB of Apr lineage II, (2) crenarchaeal SRP Caldivirga and Pyrobaculum, and (3) SOB of the distinct Apr lineage I) and the presence of potential APS reductase-interacting redox complexes. The almost identical protein matrices surrounding both [4Fe-4S] clusters, the FAD cofactor, the active site channel and center within the AprB/A models of SRP and SOB point to a highly similar catalytic process of APS reduction/sulfite oxidation independent of the metabolism type the APS reductase is involved in and the species it has been originated from. Conclusions Based on the comparative models, there are no significant structural differences between dissimilatory APS reductases from SRP and SOB; this might be indicative for a similar catalytic process of APS reduction/sulfite oxidation. PMID:18231600

  2. Characterization of a Sulfate- and U(VI)-Reducing Enrichment from Area 3 of the Oak Ridge Field Research Center

    SciTech Connect

    Nyman, Jennifer L.; Gentile, Margaret; Criddle, Craig

    2005-04-18

    The objectives of this report are to: (1) develop a sulfate-reducing enrichment from the location of the Oak Ridge FRC Area 3 field experiment; (2) assess the capacity of the enrichment community for U(VI) reduction; (3) characterize the metabolic activity of the enrichment community; (4) kinetically model microbial growth and U(VI) reduction by the enrichment; and (5) investigate the enrichment's community structure.

  3. 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

  4. 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.

  5. Electrochemical evaluation of extremely-low frequency magnetic field effects on sulphate-reducing bacteria.

    PubMed

    Fojt, L; Vetterl, V

    2012-01-01

    The effects of 50 Hz magnetic fields on sulphate- reducing bacteria viability were studied electrochemically. Two types of graphite electrodes (pyrolytic and glassy carbon) covered with whole bacterial cells behind a dialysis membrane were used for electrochemical measurements. We found about 15% decrease of reduction peak current density (which indicates desulphurization activity of the bacterial cells - their metabolic activity) on cyclic voltammograms after magnetic field exposure compared to the control samples. We suppose that the magnetic field does not influence the metabolic activity (desulphurization) of sulphate-reducing bacteria but most probably causes bacterial death. PMID:22464824

  6. 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.

  7. 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...

  8. Three manganese oxide-rich marine sediments harbor similar communities of acetate-oxidizing manganese-reducing bacteria

    PubMed Central

    Vandieken, Verona; Pester, Michael; Finke, Niko; Hyun, Jung-Ho; Friedrich, Michael W; Loy, Alexander; Thamdrup, Bo

    2012-01-01

    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 106 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

  9. 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

  10. Reducing Macrophage Proteoglycan Sulfation increases Atherosclerosis and Obesity through Enhanced Type I Interferon Signaling

    PubMed Central

    Gordts, Philip L.S.M.; Foley, Erin; Lawrence, Roger; Sinha, Risha; Lameda-Diaz, Carlos; Deng, Liwen; Nock, Ryan; Glass, Christopher K.; Erbilgin, Ayca; Lusis, Aldons J.; Witztum, Joseph L.; Esko, Jeffrey D.

    2014-01-01

    Summary Heparan sulfate proteoglycans (HSPGs) are an important constituent of the macrophage glycocalyx and extracellular microenvironment. To examine their role in atherogenesis, we inactivated the biosynthetic gene N-acetylglucosamine N-deacetylase-N-sulfotransferase 1 (Ndst1) in macrophages and crossbred the strain to Ldlr?/? mice. When placed on an atherogenic diet, Ldlr?/?Ndst1f/fLysMCre+ mice had increased atherosclerotic plaque area and volume compared to Ldlr?/? mice. Diminished sulfation of heparan sulfate resulted in enhanced chemokine expression, increased macrophages in plaques, increased expression of ACAT2, a key enzyme in cholesterol ester storage, and increased foam cell conversion. Motif analysis of promoters of up-regulated genes suggested increased Type I Interferon signaling, which was confirmed by elevation of STAT1 phosphorylation induced by IFN-?. The pro-inflammatory macrophages derived from Ndst1f/fLysMCre+ mice also sensitized the animals to diet-induced obesity. We propose that macrophage HSPGs control basal activation of macrophages by maintaining Type I interferon reception in a quiescent state through sequestration of IFN-?. PMID:25440058

  11. 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...

  12. Composition, Reactivity, and Regulations of Extracellular Metal-Reducing Structures (Bacterial Nanowires) Produced by Dissimilatory Metal Reducing Bacteria

    SciTech Connect

    Scholten, Johannes

    2006-06-01

    This research proposal seeks to describe the composition and function of electrically conductive appendages known as bacterial nanowires. This project targets bacterial nanowires produced by dissimilatory metal reducing bacteria Shewanella and Geobacter. Specifically, this project will investigate the role of these structures in the reductive transformation of iron oxides as solid phase electron acceptors, as well as uranium as a dissolved electron acceptor that forms nanocrystalline particles of uraninite upon reduction.

  13. 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

  14. 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 chromosome is located. Two other proteins - Thiosulfate reductase and ATP binding protein were found to be cytoplasmically distributed, whereas a molybdenum transporter was found to locate to the cell periphery. We judge labeling outcome by (1) SDS gel electrophoresis, followed by direct fluorescence imaging of the gel to address specificity of labeling/confirm expected molecular weight, and subsequent Coomassie analysis to ensure comparable protein levels (2) fluorescence intensity of culture by plate reader for statistical sampling (after adjustment for respective cell numbers) and (3) fluorescence microscopy for addressing cell-to-cell signal variation and potential localization patterns. All three assays were usually found to be consistent with one another. While we have been able to improve the efficacy of photoconversion by drastically reducing (eliminating) non-specific binding with our altered labeling protocol, we are currently working on reducing non-specific photoconversion reaction arising occasionally in non-labeled cells. In addition, we have confirmed the presence of SNAP tagged constructs in three recently cloned E.coli strains under promotor control, and are in the process of utilizing them for evaluating the sensitivity of the photoconversion protocol. Fluorescent Activated Cell Sorting was successfully applied to labeled E.coli cells containing SNAP tagged AtpA protein. Different batches of sorted cells, representing low and high labeling intensity, were re-grown and re-labeled and displayed a labeling efficiency similar to the starter culture, supporting the notion that cell-to-cell differences in labeling reflect difference in protein expression, rather then genetic differences.

  15. Metagenomic Analysis of Nitrate-Reducing Bacteria in the Oral Cavity: Implications for Nitric Oxide Homeostasis

    PubMed Central

    Hyde, Embriette R.; Andrade, Fernando; Vaksman, Zalman; Parthasarathy, Kavitha; Jiang, Hong; Parthasarathy, Deepa K.; Torregrossa, Ashley C.; Tribble, Gena; Kaplan, Heidi B.; Petrosino, Joseph F.; Bryan, Nathan S.

    2014-01-01

    The microbiota of the human lower intestinal tract helps maintain healthy host physiology, for example through nutrient acquisition and bile acid recycling, but specific positive contributions of the oral microbiota to host health are not well established. Nitric oxide (NO) homeostasis is crucial to mammalian physiology. The recently described entero-salivary nitrate-nitrite-nitric oxide pathway has been shown to provide bioactive NO from dietary nitrate sources. Interestingly, this pathway is dependent upon oral nitrate-reducing bacteria, since humans lack this enzyme activity. This pathway appears to represent a newly recognized symbiosis between oral nitrate-reducing bacteria and their human hosts in which the bacteria provide nitrite and nitric oxide from nitrate reduction. Here we measure the nitrate-reducing capacity of tongue-scraping samples from six healthy human volunteers, and analyze metagenomes of the bacterial communities to identify bacteria contributing to nitrate reduction. We identified 14 candidate species, seven of which were not previously believed to contribute to nitrate reduction. We cultivated isolates of four candidate species in single- and mixed-species biofilms, revealing that they have substantial nitrate- and nitrite-reduction capabilities. Colonization by specific oral bacteria may thus contribute to host NO homeostasis by providing nitrite and nitric oxide. Conversely, the lack of specific nitrate-reducing communities may disrupt the nitrate-nitrite-nitric oxide pathway and lead to a state of NO insufficiency. These findings may also provide mechanistic evidence for the oral systemic link. Our results provide a possible new therapeutic target and paradigm for NO restoration in humans by specific oral bacteria. PMID:24670812

  16. 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

  17. 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 have developed an on-grid culturing and whole-mount imaging approach, which under electron-acceptor limiting conditions resulted in the presence of filaments and vesicles making this system an interesting surrogate assay for DvH-related metal reduction under a number of environmentally relevant conditions, including stress conditions. Moreover efforts, as part of the GTL-PCAP project, are underway to correlate intracellular protein expression and localization patterns, as obtained by SNAP-tag labeling and photoconversion, with extracellular metal deposition in order to determine the respective role of the various proteins in physiology and metal reduction. We have further started to characterize by SEM and TEM the clumping behavior of DvH both wildtype and megaplasmid minus under batch liquid culture conditions, and found differences in the extracellular abundance of filaments as well as differences metal deposition patterns that occur at the onset of clumping and which may promote or indeed by responsible for clumping behavior. Clumping may be a first step of biofilm formation. For a complete understanding such morphological studies need to be accompanied by studies of protein expression through microarray analysis and possibly protein localization patterns.

  18. 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...

  19. 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.

  20. Microbial community functional structure in response to micro-aerobic conditions in sulfate-reducing sulfur-producing bioreactor.

    PubMed

    Yu, Hao; Chen, Chuan; Ma, Jincai; Xu, Xijun; Fan, Ronggui; Wang, Aijie

    2014-05-01

    Limited oxygen supply to anaerobic wastewater treatment systems had been demonstrated as an effective strategy to improve elemental sulfur (S(0)) recovery, coupling sulfate reduction and sulfide oxidation. However, little is known about the impact of dissolved oxygen (DO) on the microbial functional structures in these systems. We used a high throughput tool (GeoChip) to evaluate the microbial community structures in a biological desulfurization reactor under micro-aerobic conditions (DO: 0.02-0.33 mg/L). The results indicated that the microbial community functional compositions and structures were dramatically altered with elevated DO levels. The abundances of dsrA/B genes involved in sulfate reduction processes significantly decreased (p < 0.05, LSD test) at relatively high DO concentration (DO: 0.33 mg/L). The abundances of sox and fccA/B genes involved in sulfur/sulfide oxidation processes significantly increased (p < 0.05, LSD test) in low DO concentration conditions (DO: 0.09 mg/L) and then gradually decreased with continuously elevated DO levels. Their abundances coincided with the change of sulfate removal efficiencies and elemental sulfur (S(0)) conversion efficiencies in the bioreactor. In addition, the abundance of carbon degradation genes increased with the raising of DO levels, showing that the heterotrophic microorganisms (e.g., fermentative microorganisms) were thriving under micro-aerobic condition. This study provides new insights into the impacts of micro-aerobic conditions on the microbial functional structure of sulfate-reducing sulfur-producing bioreactors, and revealed the potential linkage between functional microbial communities and reactor performance. PMID:25079640

  1. Anaerobic degradation of naphthalene by the mixed bacteria under nitrate reducing conditions.

    PubMed

    Dou, Junfeng; Liu, Xiang; Ding, Aizhong

    2009-06-15

    Mixed bacteria were enriched from soil samples contaminated with polycyclic aromatic hydrocarbons (PAHs). The anaerobic degradation characteristics by the enriched bacteria with different initial naphthalene concentrations were investigated under nitrate reducing conditions. The results showed that the mixed bacteria could degrade nearly all the naphthalene over the incubations of 25 days when the initial naphthalene concentration was below 30 mg/L. The degradation rates of naphthalene increased with increasing initial concentrations. A high naphthalene concentration of 30 mg/L did not inhibit neither on the bacterial growth nor on the naphthalene degradation ability. The accumulation of nitrite was occurred during the reduction of nitrate, and a nitrite concentration of 50mg/L had no inhibition effect on the degradation of naphthalene. The calculation of electron balances revealed that most of the naphthalene was oxidized whereas a small proportion was used for cell synthesis. PMID:19013017

  2. A comparative study of the magnetic separation characteristics of magnetotactic and sulphate reducing bacteria

    NASA Astrophysics Data System (ADS)

    Bahaj, A. S.; James, P. A. B.; Moeschler, F. D.

    1998-06-01

    Many microorganisms have an affinity to accumulate metal ions onto their surfaces which results in metal loading of the biomass. Microbial biomineralization of iron results in a biomass which is often highly magnetic and can be separated from water systems by the application of a magnetic field. This article reports on the magnetic separation of biomass containing microbial iron oxide (Fe3O4, present within magnetotactic bacteria) and iron sulphide (Fe1-XS, precipitated extracellularly by sulphate reducing bacteria) in a single wire cell. Since such bacteria can be separated magnetically, their affinity to heavy metal or organic material accumulation render them useful for the removal of pollutants from waste water. The relative merits of each bacterium to magnetic separation techniques in terms of applied magnetic field and processing conditions are discussed.

  3. 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}}.

  4. 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

  5. Enumeration and Relative Importance of Acetylene-Reducing (Nitrogen-Fixing) Bacteria in a Delaware Salt Marsh

    PubMed Central

    Dicker, Howard J.; Smith, David W.

    1980-01-01

    Three groups of N2-fixing bacteria were enumerated from the top 1 cm of the surface in four vegetational areas in a Delaware salt marsh. The results over the 9-month sampling period showed that there were no discernible seasonal patterns for any of the groups enumerated (Azotobacter sp., Clostridium sp., and Desulfovibrio sp.). Azotobacter sp. was present in numbers of 107 per g of dry mud, whereas the two anaerobic fixers were present in much lower numbers (103 to 104 per g of dry mud). There were no differences in the numbers of each group among the different vegetational areas, indicating that there was a heterogeneous population of N2 fixers present. Additional studies indicate that the activity of sulfate reducers (Desulfovibrio sp.) may account for as much as 50% of the total observed acetylene reduction activity. Oxygen was found to exert little effect on the observed acetylene reduction activity, indicating that stable aerobic and anaerobic microenvironments exist in the surface layer of marsh sediments. PMID:16345564

  6. 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.

  7. 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 are important sources of C and S in these ecosystems. PMID:10427006

  8. 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-?m 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

  9. 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 formed extensive biofilms or flocs that contained U and V in the exopolymer, but excluded these metals from the bacteria. This suggests a specific mechanism to inhibit metal sorption to cell wall components. The example illustrates the interplay between bacteria and minerals under conditions that model oligotrophic survival, and provides insight on U mobilization from common uranium ore minerals.

  10. 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

  11. 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

  12. Improved PCR-DGGE for high resolution diversity screening of complex sulfate-reducing prokaryotic communities in soils and sediments.

    PubMed

    Miletto, Marzia; Bodelier, Paul L E; Laanbroek, Hendrikus J

    2007-07-01

    In this study we evaluated a high resolution PCR-DGGE strategy for the characterization of complex sulfate-reducing microbial communities inhabiting natural environments. dsrB fragments were amplified with a two-step nested PCR protocol using combinations of primers targeting the dissimilatory (bi)sulfite reductase genes. The PCR-DGGE conditions were initially optimized using a dsrAB clone library obtained from a vegetated intertidal riparian soil along the river Rhine (Rozenburg, the Netherlands). Partial dsrB were successfully amplified from the same environmental DNA extracts used to construct the library, DGGE-separated and directly sequenced. The two approaches were in good agreement: the phylogenetic distribution of clones and DGGE-separated dsrB was comparable, suggesting the presence of sulfate-reducing prokaryotes (SRP) belonging to the families 'Desulfobacteraceae,' 'Desulfobulbaceae' and 'Syntrophobacteraceae,' and to the Desulfomonile tiedjei- and Desulfobacterium anilini-groups. The nested PCR-DGGE was also used to analyze sediment samples (Appels, Belgium) from a series of microcosms subjected to a tidal flooding regime with water of different salinity, and proved to be a valid tool also to monitor the SRP community variation over time and space as a consequence of environmental changes. PMID:17481757

  13. Removal of chromium and lead by a sulfate-reducing consortium using peat moss as carbon source.

    PubMed

    Márquez-Reyes, Julia Mariana; López-Chuken, Ulrico Javier; Valdez-González, Arcadio; Luna-Olvera, Hugo Alberto

    2013-09-01

    The effect of pre-treated peat moss on the ability of a sulfate-reducing microbial consortium to remove chromium and lead in solution was evaluated. The most active bacterial community (235.7 mmol H2S/g VSS) was selected from among eight consortia. The peat moss was pre-treated with different HCl concentrations and contact times. The best combination of treatments was 20% HCl for 10 min. The constant substrate affinity Ks was 740 mg COD/L and the ratio COD/SO4(2-) was 0.71. At pH 5, higher production of biogenic sulfide was observed. The up-flowpacked bed bioreactor operated at a flow of 8.3 mL/min for 180 h to obtain removal efficiency (by sulfate-reducing activity) of 90% lead and 65% chromium. It is important to consider that peat moss is a natural adsorbent that further influences the removal efficiency of metal ions. PMID:23859988

  14. Isolation and characterization of arsenate-reducing bacteria from arsenic-contaminated sites in New Zealand.

    PubMed

    Anderson, Craig R; Cook, Gregory M

    2004-05-01

    Two environmental sites in New Zealand were sampled (e.g., water and sediment) for bacterial isolates that could use either arsenite as an electron donor or arsenate as an electron acceptor under aerobic and anaerobic growth conditions, respectively. These two sites were subjected to widespread arsenic contamination from mine tailings generated from historic gold mining activities or from geothermal effluent. No bacteria were isolated from these sites that could utilize arsenite or arsenate under the respective growth conditions tested, but a number of chemoheterotrophic bacteria were isolated that could grow in the presence of high concentrations of arsenic species. In total, 17 morphologically distinct arsenic-resistant heterotrophic bacteria isolates were enriched from the sediment samples, and analysis of the 16S rRNA gene sequence of these bacteria revealed them to be members of the genera Exiguobacterium, Aeromonas, Bacillus, Pseudomonas, Escherichia, and Acinetobacter. Two isolates, Exiguobacterium sp. WK6 and Aeromonas sp. CA1, were of particular interest because they appeared to gain metabolic energy from arsenate under aerobic growth conditions, as demonstrated by an increase in cellular growth yield and growth rate in the presence of arsenate. Both bacteria were capable of reducing arsenate to arsenite via a non-respiratory mechanism. Strain WK6 was positive for arsB, but the pathway of arsenate reduction for isolate CA1 was via a hitherto unknown mechanism. These isolates were not gaining an energetic advantage from arsenate or arsenite utilization, but were instead detoxifying arsenate to arsenite. As a subsidiary process to arsenate reduction, the external pH of the growth medium increased (i.e., became more alkaline), allowing these bacteria to grow for extended periods of time. PMID:15060729

  15. 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.

  16. Changes in Multidrug Resistance of Enteric Bacteria following an Intervention To Reduce Antimicrobial Resistance in Dairy Calves ▿

    PubMed Central

    Kaneene, John B.; Warnick, Lorin D.; Bolin, Carole A.; Erskine, Ronald J.; May, Katherine; Miller, RoseAnn

    2009-01-01

    An intervention study was conducted to determine whether discontinuing the feeding of milk replacer medicated with oxytetracycline and neomycin to preweaned calves reduced antimicrobial resistance in Salmonella, Campylobacter, and Escherichia coli bacteria. Results demonstrated that the intervention did reduce multidrug resistance in these bacteria but that other factors also influenced multidrug resistance. PMID:19846639

  17. 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

  18. 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

  19. 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

  20. 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.

  1. Glucosamine sulfate

    MedlinePlus

    ... Glucosamine Sulphate KCl, Glucosamine-6-Phosphate, GS, Mono-Sulfated Saccharide, Poly-(1->3)-N-Acetyl-2-Amino- ... Sulfate de Glucosamine, Sulfate de Glucosamine 2KCl, SG, Sulfated Monosaccharide, Sulfated Saccharide, Sulfato de Glucosamina. Glucosamine Hydrochloride ...

  2. 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

  3. Thermodesulfobacterium geofontis sp. nov., a hyperthermophilic, sulfate-reducing bacterium isolated from Obsidian Pool, Yellowstone National Park

    SciTech Connect

    Hamilton-Brehm, Scott; Gibson, Robert; Green, Stefan; Hopmans, Ellen; Schouten, Stefan; van der Meer, Marcel T. J.; Shields, John; S. Damste, Jaap S.; Elkins, James G

    2013-01-01

    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.

  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. 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).

  6. 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.

  7. 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

  8. Effect of sulfate addition on methane production and sulfate reduction in a mesophilic acetate-fed anaerobic reactor.

    PubMed

    Yang, Sen-Lin; Tang, Yue-Qin; Gou, Min; Jiang, Xia

    2015-04-01

    A mesophilic anaerobic moving bed biofilm reactor (MBBR) was operated to evaluate the effect of sulfate addition on methane production and sulfate reduction using acetate as the sole carbon source. The results show that at the organic loading rate of 4.0 g TOC/L/day, the TOC removal efficiencies and the biogas production rates achieved over 95 % and 7000 mL/L/day without sulfate, respectively, and slightly decreased with sulfate addition (500-800 mg/L). Methane production capacities were not influenced significantly with the addition of sulfate, while sulfate reduction efficiencies were not stable with 23-87 % in the acetate-fed reactor. Fluorescent in situ hybridization (FISH) was used to analyze the functional microbial compositions of acetate-degrading methane-producing bacteria (MPB) and sulfate-reducing bacteria (SRB) in the reactor. The results found that as the increase of sulfate concentration, the proportion of Methanomicrobiales increased up to 58 ± 2 %, while Methanosaeta and Methanosarcina decreased. The dominant methanogens shifted into hydrogenotrophic methanogens from even distribution of acetoclastic and hydrogenotrophic methanogens. When hydrogenotrophic methanogens were dominant, sulfate reduction efficiency was high, while sulfate reduction efficiency was low as acetoclastic methanogens were dominant. PMID:25427678

  9. Recovery of Humic-Reducing Bacteria from a Diversity of Environments

    PubMed Central

    Coates, John D.; Ellis, Debra J.; Blunt-Harris, Elizabeth L.; Gaw, Catherine V.; Roden, Eric E.; Lovley, Derek R.

    1998-01-01

    To evaluate which microorganisms might be responsible for microbial reduction of humic substances in sedimentary environments, humic-reducing bacteria were isolated from a variety of sediment types. These included lake sediments, pristine and contaminated wetland sediments, and marine sediments. In each of the sediment types, all of the humic reducers recovered with acetate as the electron donor and the humic substance analog, 2,6-anthraquinone disulfonate (AQDS), as the electron acceptor were members of the family Geobacteraceae. This was true whether the AQDS-reducing bacteria were enriched prior to isolation on solid media or were recovered from the highest positive dilutions of sediments in liquid media. All of the isolates tested not only conserved energy to support growth from acetate oxidation coupled to AQDS reduction but also could oxidize acetate with highly purified soil humic acids as the sole electron acceptor. All of the isolates tested were also able to grow with Fe(III) serving as the sole electron acceptor. This is consistent with previous studies that have suggested that the capacity for Fe(III) reduction is a common feature of all members of the Geobacteraceae. These studies demonstrate that the potential for microbial humic substance reduction can be found in a wide variety of sediment types and suggest that Geobacteraceae species might be important humic-reducing organisms in sediments. PMID:9546186

  10. Behavioral response of dissimilatory perchlorate-reducing bacteria to different electron acceptors.

    PubMed

    Sun, Yvonne; Gustavson, Ruth L; Ali, Nadia; Weber, Karrie A; Westphal, Lacey L; Coates, John D

    2009-10-01

    The response behavior of three dissimilatory perchlorate-reducing bacteria to different electron acceptors (nitrate, chlorate, and perchlorate) was investigated with two different assays. The observed response was species-specific, dependent on the prior growth conditions, and was inhibited by oxygen. We observed attraction toward nitrate when Dechloromonas aromatica strain RCB and Azospira suillum strain PS were grown with nitrate. When D. aromatica and Dechloromonas agitata strain CKB were grown with perchlorate, both responded to nitrate, chlorate, and perchlorate. When A. suillum was grown with perchlorate, the organism responded to chlorate and perchlorate but not nitrate. A gene replacement mutant in the perchlorate reductase subunit (pcrA) of D. aromatica resulted in a loss of the attraction response toward perchlorate but had no impact on the nitrate response. Washed-cell suspension studies revealed that the perchlorate grown cells of D. aromatica reduced both perchlorate and nitrate, while A. suillum cells reduced perchlorate only. Based on these observations, energy taxis was proposed as the underlying mechanism for the responses to (per)chlorate by D. aromatica. To the best of our knowledge, this study represents the first investigation of the response behavior of perchlorate-reducing bacteria to environmental stimuli. It clearly demonstrates attraction toward chlorine oxyanions and the unique ability of these organisms to distinguish structurally analogous compounds, nitrate, chlorate, and perchlorate and respond accordingly. PMID:19533120

  11. 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 of plutonium in the subsurface.

  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 the sediment-attached microbial communities were dominated by 5 TRFs, that comprised 25-57% of the total profile.

  13. Growth and cometabolic reduction kinetics of a uranium- and sulfate-reducing Desulfovibrio/Clostridia mixed culture: Temperature effects.

    PubMed

    Boonchayaanant, Benjaporn; Kitanidis, Peter K; Criddle, Craig S

    2008-04-01

    Bioremediation of contaminated soils and aquifers is subject to spatial and temporal temperature changes that can alter the kinetics of key microbial processes. This study quantifies temperature effects on the kinetics of an ethanol-fed sulfate-reducing mixed culture derived from a uranium-contaminated aquifer subject to seasonal temperature fluctuations. The mixed culture contains Desulfovibrio sp. and a Clostridia-like organism. Rates of growth, ethanol utilization, decay, and uranium reduction decreased with decreasing temperature. No significant uranium reduction was observed at 10 degrees C. While both Monod saturation kinetics and pseudo second-order kinetics adequately described the rates of growth and utilization of electron donor (ethanol), model parameters for the pseudo second-order expression had smaller uncertainties. Uranium reduction kinetics were best described by pseudo second-order kinetics modified to include a term for inactivation/death of cells. PMID:17929318

  14. Direct and Fe(II)-Mediated Reduction of Technetium by Fe(III)-Reducing Bacteria

    PubMed Central

    Lloyd, J. R.; Sole, V. A.; Van Praagh, C. V. G.; Lovley, D. R.

    2000-01-01

    The dissimilatory Fe(III)-reducing bacterium Geobacter sulfurreducens reduced and precipitated Tc(VII) by two mechanisms. Washed cell suspensions coupled the oxidation of hydrogen to enzymatic reduction of Tc(VII) to Tc(IV), leading to the precipitation of TcO2 at the periphery of the cell. An indirect, Fe(II)-mediated mechanism was also identified. Acetate, although not utilized efficiently as an electron donor for direct cell-mediated reduction of technetium, supported the reduction of Fe(III), and the Fe(II) formed was able to transfer electrons abiotically to Tc(VII). Tc(VII) reduction was comparatively inefficient via this indirect mechanism when soluble Fe(III) citrate was supplied to the cultures but was enhanced in the presence of solid Fe(III) oxide. The rate of Tc(VII) reduction was optimal, however, when Fe(III) oxide reduction was stimulated by the addition of the humic analog and electron shuttle anthaquinone-2,6-disulfonate, leading to the rapid formation of the Fe(II)-bearing mineral magnetite. Under these conditions, Tc(VII) was reduced and precipitated abiotically on the nanocrystals of biogenic magnetite as TcO2 and was removed from solution to concentrations below the limit of detection by scintillation counting. Cultures of Fe(III)-reducing bacteria enriched from radionuclide-contaminated sediment using Fe(III) oxide as an electron acceptor in the presence of 25 ?M Tc(VII) contained a single Geobacter sp. detected by 16S ribosomal DNA analysis and were also able to reduce and precipitate the radionuclide via biogenic magnetite. Fe(III) reduction was stimulated in aquifer material, resulting in the formation of Fe(II)-containing minerals that were able to reduce and precipitate Tc(VII). These results suggest that Fe(III)-reducing bacteria may play an important role in immobilizing technetium in sediments via direct and indirect mechanisms. PMID:10966385

  15. Carbon Isotope Fractionation during Anaerobic Degradation of Methyl tert-Butyl Ether under Sulfate-Reducing and Methanogenic Conditions

    PubMed Central

    Somsamak, Piyapawn; Richnow, Hans H.; Hggblom, Max M.

    2006-01-01

    Methyl tert-butyl ether (MTBE), an octane enhancer and a fuel oxygenate in reformulated gasoline, has received increasing public attention after it was detected as a major contaminant of water resources. Although several techniques have been developed to remediate MTBE-contaminated sites, the fate of MTBE is mainly dependent upon natural degradation processes. Compound-specific stable isoto