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. Monitoring sulfide and sulfate-reducing bacteria

    SciTech Connect

    Tanner, R.S.

    1995-12-31

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

  3. Iron availability in mixed cultures of sulfate-reducing bacteria

    SciTech Connect

    Hauser, J.Y.; Holder, G.A.

    1986-01-01

    Postgate's medium C was found to be unsuitable for quantitative studies of mixed microbial cultures containing sulfate-reducing bacteria. Equilibrium calculations of iron concentration, along with the experimental observations show that precipitation of iron occurs in Postgate's medium, despite the presence of citrate and yeast extract. The often ascribed inhibitory effect of sulfide on the growth of sulfate-reducing bacteria may be largely due to the reduced availability of iron, as a result of the precipitation of ferrous sulfide. Because it is essential to clearly define the growth limiting nutrient when carrying out quantitative bacterial growth studies, yeast extract should be excluded from the culture medium. Single-phase, exponential growth was observed for mixed cultures containing sulfate-reducing bacteria, using a chemically defined medium that incorporated the metal complexing agent EDTA. When carrying out quantitative kinetic studies of sulfate-reducing bacteria, a chemically defined medium incorporating EDTA is recommended.

  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. Comparative biocidal efficacy vs. sulfate-reducing bacteria

    SciTech Connect

    Grab, L.A.; Theis, A.B. (Union Carbide Chemicals and Plastics Co. Inc., Bound Brook, NJ (United States))

    1993-06-01

    A number of antimicrobial compounds commonly used in cooling water, paper making, and oilfield systems were evaluated for their ability to control sessile and planktonic sulfate-reducing bacteria (SRB). While all the biocides tested are known to be effective against common planktonic, general aerobic bacteria, most were unable to control either planktonic or sessile SRB. In addition, low levels of sulfide, an SRB by-product, were found to have some effect on biocide efficacy.

  6. Sulfate reducing bacteria in microbial mats: Changing paradigms, new discoveries

    Microsoft Academic Search

    L. K. Baumgartner; R. P. Reid; C. Dupraz; A. W. Decho; D. H. Buckley; J. R. Spear; K. M. Przekop; P. T. Visscher

    2006-01-01

    Sulfate reducing bacteria (SRB) have existed throughout much of Earth's history and remain major contributors to carbon cycling in modern systems. Despite their importance, misconceptions about SRB are prevalent. In particular, SRB are commonly thought to lack oxygen tolerance and to exist only in anoxic environments. Through the last two decades, researchers have discovered that SRB can, in fact, tolerate

  7. 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

  8. New bactericide for biocide-resistant sulfate-reducing bacteria

    SciTech Connect

    Liu Hongfang; Xu Liming; Zheng Jiashen; Liu Jing

    2000-04-01

    Biocide-resistant sulfate-reducing bacteria (SRB) cause low efficacy of bactericides, and there is a high cost of killing the bacteria. A new bactericide, bisquaternary ammonium compound (BQA), has been synthesized in the laboratory. The performance of BQA was tested alone and in combination with metronidazol flagyl (ME). The results show that the biocide-resistant SRB induced by 1227 bactericide (dodecyldimethyl-benzyl ammonium chloride) can be controlled by BQA combined with ME. The equivalent curve indicates synergistic efficacy of BQA and ME. They work together to stifle SRB (especially the biocide-resistant bacteria) at low cost, not only in the laboratory, but also in the oil field, allowing reduced use of toxic commercial biocides.

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

    PubMed

    Barton, Larry L; Fauque, Guy D

    2009-01-01

    Chemolithotrophic bacteria that use sulfate as terminal electron acceptor (sulfate-reducing bacteria) constitute a unique physiological group of microorganisms that couple anaerobic electron transport to ATP synthesis. These bacteria (220 species of 60 genera) can use a large variety of compounds as electron donors and to mediate electron flow they have a vast array of proteins with redox active metal groups. This chapter deals with the distribution in the environment and the major physiological and metabolic characteristics of sulfate-reducing bacteria (SRB). This chapter presents our current knowledge of soluble electron transfer proteins and transmembrane redox complexes that are playing an essential role in the dissimilatory sulfate reduction pathway of SRB of the genus Desulfovibrio. Environmentally important activities displayed by SRB are a consequence of the unique electron transport components or the production of high levels of H(2)S. The capability of SRB to utilize hydrocarbons in pure cultures and consortia has resulted in using these bacteria for bioremediation of BTEX (benzene, toluene, ethylbenzene and xylene) compounds in contaminated soils. Specific strains of SRB are capable of reducing 3-chlorobenzoate, chloroethenes, or nitroaromatic compounds and this has resulted in proposals to use SRB for bioremediation of environments containing trinitrotoluene and polychloroethenes. Since SRB have displayed dissimilatory reduction of U(VI) and Cr(VI), several biotechnology procedures have been proposed for using SRB in bioremediation of toxic metals. Additional non-specific metal reductase activity has resulted in using SRB for recovery of precious metals (e.g. platinum, palladium and gold) from waste streams. Since bacterially produced sulfide contributes to the souring of oil fields, corrosion of concrete, and discoloration of stonework is a serious problem, there is considerable interest in controlling the sulfidogenic activity of the SRB. The production of biosulfide by SRB has led to immobilization of toxic metals and reduction of textile dyes, although the process remains unresolved, SRB play a role in anaerobic methane oxidation which not only contributes to carbon cycle activities but also depletes an important industrial energy reserve. PMID:19426853

  10. 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.

  11. Effects of sulfate reducing bacteria and sulfate concentrations on mercury methylation in freshwater sediments.

    PubMed

    Shao, Dingding; Kang, Yuan; Wu, Shengchun; Wong, Ming H

    2012-05-01

    Methylmercury (MeHg) is the most poisonous form of mercury (Hg) and it enters the human body primarily through consumption of Hg contaminated fish. Sulfate reducing bacteria (SRB) are major producers of MeHg in anoxic sediments. The dsrAB gene was isolated from freshwater fish pond sediments. Sequence analyses showed that the SRB in sediments was mainly composed of Desulfobulbus propionicus and Desulfovibrio vulgaris. The two species of SRB were cultured from freshwater sediments. The addition of inorganic Hg to these freshwater sediments caused an increase in MeHg concentrations at 30 days incubation. MeHg levels were sensitive to sulfate concentrations; a medium sulfate level (0.11 mg/g) produced higher levels than treatments lacking sulfate addition or when amended with 0.55 mg/g. Assessment of bacterial levels by PCR measurements of microbial DNA indicated that the MeHg levels were correlated with cell growth. PMID:22444059

  12. Sulfate-reducing bacteria and their activities in oil production

    SciTech Connect

    Cord-Ruwisch, R.; Kleinitz, W.; Widdell, F.

    1987-01-01

    This paper presents an overview of the microbiology of sulfate-reducing bacteria (SRB) and their detrimental effects in oil technology and summarizes a study on SRB in an oil field. SRB are a group of specialized microorganisms that occur in aqueous environments in the absence of oxygen. The main nutrients for SRB are simple organic acids and molecular hydrogen (H/sub 2/) from decomposing natural organic matter. The nutrients are oxidized, with sulfate being reduced to sulfide (hydrogen sulfide, H/sub 2/S). The formed H/sub 2/S is the principal agent in the disastrous effects caused by SRB. It contaminates gas and stored oil, precipitates ferrous sulfide that plugs injection wells, and promotes corrosion of iron and steel in the absence of oxygen (anaerobic corrosion). Another principal mechanism by which SRB are involved in corrosion is their ability to depolarize iron surfaces by consumption of cathodically formed hydrogen. The postulate mechanisms in anaerobic corrosion are briefly explained. As an example for a microbiological study of SRB in oil technology, examination of an oil treater in a field in northern Germany is presented. On the basis of measured growth characteristics of the SRB, possibilities for controlling their activity are discussed.

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

    SciTech Connect

    Thompson, D.N.; Sayer, R.L.; Noah, K.S. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    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.

  14. Effects of sulfate reducing bacteria and sulfate concentrations on mercury methylation in freshwater sediments

    Microsoft Academic Search

    Dingding Shao; Yuan Kang; Shengchun Wu; Ming H. Wong

    Methylmercury (MeHg) is the most poisonous form of mercury (Hg) and it enters the human body primarily through consumption of Hg contaminated fish. Sulfate reducing bacteria (SRB) are major producers of MeHg in anoxic sediments. The dsrAB gene was isolated from freshwater fish pond sediments. Sequence analyses showed that the SRB in sediments was mainly composed of Desulfobulbus propionicus and

  15. SULFATE-REDUCING BACTERIA IN THE SEAGRASS RHIZOSPHERE

    EPA Science Inventory

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

  16. Distribution of Methanogenic and Sulfate-Reducing Bacteria in Near-Shore Marine Sediments

    PubMed Central

    Hines, Mark E.; Buck, John D.

    1982-01-01

    The distribution of methanogenic and sulfate-reducing bacteria was examined in sediments from three sites off the coast of eastern Connecticut and five sites in Long Island Sound. Both bacterial groups were detected at all sites. Three distributional patterns were observed: (i) four sites exhibited methanogenic and sulfate-reducing populations which were restricted to the upper 10 to 20 cm, with a predominance of sulfate reducers; (ii) three sites in western Long Island Sound exhibited a methanogenic population most abundant in sediments deeper than those occupied by sulfate reducers; (iii) at one site that was influenced by fresh groundwater, methanogens and sulfate reducers were numerous within the same depths; however, the number of sulfate reducers varied vertically and temporally with sulfate concentrations. It was concluded that the distributions of abundant methanogenic and sulfate-reducing bacteria were mutually exclusive. Methanogenic enrichments yielded all genera of methanogens except Methanosarcina, with the methanobacteria predominating. PMID:16345950

  17. Novel thermophilic sulfate-reducing bacteria from a geothermally active underground mine in Japan.

    PubMed

    Kaksonen, Anna H; Plumb, Jason J; Robertson, Wendy J; Spring, Stefan; Schumann, Peter; Franzmann, Peter D; Puhakka, Jaakko A

    2006-05-01

    Thermophilic sulfate-reducing bacteria were enriched from samples obtained from a geothermal underground mine in Japan. The enrichment cultures contained bacteria affiliated with the genera Desulfotomaculum, Thermanaeromonas, Thermincola, Thermovenabulum, Moorella, "Natronoanaerobium," and Clostridium. Two novel thermophilic sulfate-reducing strains, RL50JIII and RL80JIV, affiliated with the genera Desulfotomaculum and Thermanaeromonas, respectively, were isolated. PMID:16672530

  18. Interrelationships between sulfate reducing and methane producing bacteria in coastal sediments with intense sulfide production

    Microsoft Academic Search

    L. Å. H. Gunnarsson; P. H. Rönnow

    1982-01-01

    Coastal sediments receiving different amounts of organic carbon through sedimentation were investigated with respect to sulfate reduction and methanogenic activity. Sampling was carried out at sediment temperatures of 7° and 15°C. Sulfate-reducing and methanogenic bacteria were found at all depths. Sulfate reduction decreased with depth and the highest sulfide concentrations were found a few centimeters below the sediment surface, up

  19. 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.

  20. 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...

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

    SciTech Connect

    Misken, K.A.; Figueroa, L.A. [Colorado School of Mines, Golden, CO (United States)

    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.

  2. Molecular and microscopic identification of sulfate-reducing bacteria in multispecies biofilms

    Microsoft Academic Search

    R. I. Amann; J. Stromley; R. Devereux; D. A. Stahl

    1992-01-01

    The population architecture of sulfidogenic biofilms established in anaerobic fixed-bed bioreactors was characterized by selective polymerase chain reaction amplification and fluorescence microscopy. A region of the 16S rRNA common to resident sulfate-reducing bacteria was selectively amplified by the polymerase chain reaction. Sequences of amplification products, with reference to a collection of 16S rRNA sequences representing most characterized sulfate-reducing bacteria, were

  3. Cadmium Accumulation and DNA Homology with Metal Resistance Genes in Sulfate-Reducing Bacteria

    Microsoft Academic Search

    Naghma Naz; Hilary K. Young; Nuzhat Ahmed; Geoffrey M. Gadd

    2005-01-01

    Cadmium resistance (0.1 to 1.0 mM) was studied in four pure and one mixed culture of sulfate-reducing bacteria (SRB). The growth of the bacteria was monitored with respect to carbon source (lactate) oxidation and sulfate reduction in the presence of various concentrations of cadmium chloride. Two strains Desulfovibrio desulfuricans DSM 1926 and Desulfococcus multivorans DSM 2059 showed the highest resistance

  4. Sulfate-Reducing Bacteria and Their Activities in Cyanobacterial Mats of Solar Lake (Sinai, Egypt)

    PubMed Central

    Teske, Andreas; Ramsing, Niels B.; Habicht, Kirsten; Fukui, Manabu; Küver, Jan; Jørgensen, Bo Barker; Cohen, Yehuda

    1998-01-01

    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 106 and 107 cultivable sulfate-reducing bacteria ml?1 and showed sulfate reduction rates between 1,000 and 2,200 nmol ml?1 day?1, both in the same range as and sometimes higher than those in anaerobic deeper mat layers. In the oxic surface layer and in the mat layers below, filamentous sulfate-reducing Desulfonema bacteria were found in variable densities of 104 to 106 cells ml?1. A Desulfonema-related, diurnally migrating bacterium was detected with PCR and denaturing gradient gel electrophoresis within and below the oxic surface layer. Facultative aerobic respiration, filamentous morphology, motility, diurnal migration, and aggregate formation were the most conspicuous adaptations of Solar Lake sulfate-reducing bacteria to the mat matrix and to diurnal oxygen stress. A comparison of sulfate reduction rates within the mat and previously published photosynthesis rates showed that CO2 from sulfate reduction in the upper 5 mm accounted for 7 to 8% of the total photosynthetic CO2 demand of the mat. PMID:9687455

  5. Sulfate reducing and methane producing bacteria in aerobic wastewater treatment systems

    Microsoft Academic Search

    P. N. Lens; M.-P. De Poorter; C. C. Cronenberg; W. H. Verstraete

    1995-01-01

    A selection of aerobic biofilm reactors and activated sludge plants were investigated for the presence of methane producing bacteria (MPB) and sulfate reducing bacteria (SRB). Detection tests showed that acetotrophic and hydrogenotrophic MPB as well as lactate, acetate and propionate oxidizing SRB were present in all reactor types investigated, except in an activated sludge reactor aerated with pure oxygen. Methane

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

    PubMed

    Lovley, D R; Phillips, E J

    1994-07-01

    Sulfate reducers and related organisms which had previously been found to reduce Fe(III) with H(2) or organic electron donors oxidized S 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 S 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 S + 3 MnO(2) + 4H-->SO(4) + 3Mn(II) + 2H(2)O. None of the organisms evaluated could be grown with S 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 S 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 S as follows: 4S + 4H(2)O-->SO(4) + 3HS + 5 H. Growth of Desulfobulbus propionicus with S as the electron donor and Fe(III) as a sulfide sink and/or electron acceptor was very slow. The S 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 S. PMID:16349323

  7. 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.

  8. 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.

  9. Quantifying sulfate reducing bacteria in microbiologically influenced corrosion. (Reannouncement with new availability information). Final report

    SciTech Connect

    Little, B.; Wagner, P.

    1992-11-01

    Iron-oxidizing, sulfur-oxidizing, iron-reducing, sulfate-reducing, acid producing, slime-producing, ammonium-producing, and hydrogen-producing bacteria in addition to other physiological groups have been implicated in the corrosion of metals and alloys. However, the most widely recognized and most easily detected bacteria in most corrosion processes are the bacteria that reduce sulfate to sulfide that are collectively called sulfate-reducing bacteria (SRB). SRB constitute a physiological-ecological assemblage of morphologically very different types of anaerobic bacteria that have in common the capacity to reduce sulfate to hydrogen sulfide in dissimilatory energy-conserving reactions. Hydrogen sulfide can react with metals to produce metal sulfides as corrosion products. Most techniques for the evaluation of SRB populations are related to their potential to cause microbiologically influenced corrosion (MIC). Standard practices for evaluating the contribution of SRB to corrosion processes depend on the detection and quantification of SRB using culturing techniques that enumerate organisms or quantify intrinsic characteristics of SRB including enzymes and antibodies. Mineralogy of metal sulfides and sulfur isotope fractionation can also be used to verify the involvement of SRB in corrosion. This paper will review standard practices and innovative techniques for detecting and quantifying SRB.

  10. Organic Substrates in Bioremediation of Acidic Saline Drainage Waters by Sulfate-Reducing Bacteria

    Microsoft Academic Search

    Talitha C. Santini; Brad P. Degens; Andrew W. Rate

    2010-01-01

    Deep drains used to manage shallow saline water tables in the Western Australian agricultural region discharge acidic, saline\\u000a drainage water with high concentrations of metals. The activity of sulfate-reducing bacteria can treat these waters by generating\\u000a alkalinity in the form of bicarbonate and by generating sulfide, which removes metals from solution as sulfide precipitates.\\u000a Bacterial sulfate reduction was strongly influenced

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

    SciTech Connect

    Al-Ani, W.A.G.; Henry, J.G.; Prasad, D. [Univ. of Toronto, Ontario (Canada)

    1996-11-01

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

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

    PubMed Central

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

    2015-01-01

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

  13. Studies on dissimilatory sulfate-reducing bacteria that decompose fatty acids

    Microsoft Academic Search

    Friedrich Widdel; Gert-Wieland Kohring; Frank Mayer

    1983-01-01

    Gliding motility, ultrastructure and nutrition of two newly isolated filamentous sulfate-reducing bacteria, strains 5ac10 and 4be13, were investigated. The filaments were always attached to surfaces. Growth was supported by addition of insoluble aluminium phosphate or agar as substrata for gliding movement. Electron microscopy of ultrathin sections revealed cell walls characteristic of Gramnegative bacteria; the undulated structure of the outer membrane

  14. Comparative Analysis of Methane-Oxidizing Archaea and Sulfate-Reducing Bacteria in Anoxic Marine Sediments

    Microsoft Academic Search

    V. J. Orphan; K.-U. Hinrichs; W. USSLER III; C. K. Paull; L. T. Taylor; S. P. Sylva; J. M. Hayes; E. F. Delong

    2001-01-01

    The oxidation of methane in anoxic marine sediments is thought to be mediated by a consortium of meth- ane-consuming archaea and sulfate-reducing bacteria. In this study, we compared results of rRNA gene (rDNA) surveys and lipid analyses of archaea and bacteria associated with methane seep sediments from several different sites on the Californian continental margin. Two distinct archaeal lineages (ANME-1

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

    SciTech Connect

    Takahashi, Yui; Suto, Koichi; Inoue, Chihiro; Chida, Tadashi [Graduate School of Environmental Studies, Tohoku University, Aoba 6-6-20, Aramaki, Aoba-ku, Sendai (Japan)

    2006-05-15

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

  16. Amino acid degradation by sulfate-reducing bacteria: Evaluation of four methods

    Microsoft Academic Search

    LARS STENVANG HANSEN; Thlomas Henry Blackburn

    1995-01-01

    Four methods were cvalulted for estimating the proportion of dissolved free amino acids (DFAAs) me- tabolized by sulfate-reducing bacteria (SRB). Our main aim was to assess the problems associated with each method, each of which used molybdate (MO) as an inhibitor of SRB activity. MO had some side effects that clouded interpretation of the results. MO treatment did not increase

  17. 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 ...

  18. Inorganic carbon fixation by sulfate-reducing bacteria in the Black Sea water column

    Microsoft Academic Search

    Lev N. Neretin; Raeid M. M. Abed; Axel Schippers; Carsten J. Schubert; Katharina Kohls; Marcel M. M. Kuypers

    2007-01-01

    Summary The Black Sea is the largest anoxic water basin on Earth and its stratified water column comprises an upper oxic, middle suboxic and a lower permanently anoxic, sulfidic zone. The abundance of sulfate- reducing bacteria (SRB) in water samples was deter- mined by quantifying the copy number of the dsrA gene coding for the alpha subunit of the dissimilatory

  19. Methylmercury and sulfate-reducing bacteria in mangrove sediments from Jiulong River Estuary, China

    Microsoft Academic Search

    Hao Wu; Zhenhua Ding; Yang Liu; Jinling Liu; Haiyu Yan; Jiayong Pan; Liuqiang Li; Huina Lin; Guanghui Lin; Haoliang Lu

    2011-01-01

    Estuaries are important sites for mercury (Hg) methylation, with sulfate-reducing bacteria (SRB) thought to be the main Hg methylators. Distributions of total mercury (THg) and methylmercury (MeHg) in mangrove sediment and sediment core from Jiulong River Estuary Provincial Mangrove Reserve, China were determined and the possible mechanisms of Hg methylation and their controlling factors in mangrove sediments were investigated. Microbiological

  20. Importance of sulfate reducing bacteria in mercury methylation and demethylation in periphyton from Bolivian Amazon region

    Microsoft Academic Search

    Darío Achá; Holger Hintelmann; Janet Yee

    2011-01-01

    Sulfate reducing bacteria (SRB) are important mercury methylators in sediments, but information on mercury methylators in other compartments is ambiguous. To investigate SRB involvement in methylation in Amazonian periphyton, the relationship between Hg methylation potential and SRB (Desulfobacteraceae, Desulfobulbaceae and Desulfovibrionaceae) abundance in Eichhornia crassipes and Polygonum densiflorum root associated periphyton was examined. Periphyton subsamples of each macrophyte were amended

  1. A green biocide enhancer for the treatment of sulfate-reducing bacteria (SRB) biofilms on carbon steel surfaces using glutaraldehyde

    E-print Network

    Gu, Tingyue

    A green biocide enhancer for the treatment of sulfate-reducing bacteria (SRB) biofilms on carbon, was found to enhance the efficacy of glutaraldehyde in its treatment of sulfate- reducing bacteria (SRB dosages considerably in the inhibition of SRB biofilm establishment and the treatment of established

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

    PubMed Central

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

    2002-01-01

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

  3. 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

  4. The use of magnesium peroxide for the inhibition of sulfate-reducing bacteria under anoxic conditions

    Microsoft Academic Search

    Yu-Jie Chang; Yi-Tang Chang; Chun-Hsiung Hung

    2008-01-01

    Sulfate-reducing bacteria (SRB), which cause microbiologically influenced material corrosion under anoxic conditions, form\\u000a one of the major groups of microorganisms responsible for the generation of hydrogen sulfide. In this study, which is aimed\\u000a at reducing the presence of SRB, a novel alternative approach involving the addition of magnesium peroxide (MgO2) compounds involving the use of reagent-grade MgO2 and a commercial

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

    PubMed Central

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

    1991-01-01

    Granules from an upflow anaerobic sludge blanket system treating a brewery wastewater that contained mainly ethanol, propionate, and acetate as carbon sources and sulfate (0.6 to 1.0 mM) were characterized for their physical and chemical properties, metabolic performance on various substrates, and microbial composition. Transmission electron microscopic examination showed that at least three types of microcolonies existed inside the granules. One type consisted of Methanothrix-like rods with low levels of Methanobacterium-like rods; two other types appeared to be associations between syntrophic-like acetogens and Methanobacterium-like organisms. The granules were observed to be have numerous vents or channels on the surface that extended into the interior portions of the granules that may be involved in release of gas formed within the granules. The maximum substrate conversion rates (millimoles per gram of volatile suspended solids per day) at 35 degrees C in the absence of sulfate were 45.1, 8.04, 4.14, and 5.75 for ethanol, acetate, propionate, and glucose, respectively. The maximum methane production rates (millimoles per gram of volatile suspended solids per day) from H2-CO2 and formate were essentially equal for intact granules (13.7 and 13.5) and for physically disrupted granules (42 and 37). During syntrophic ethanol conversion, both hydrogen and formate were formed by the granules. The concentrations of these two intermediates were maintained at a thermodynamic equilibrium, indicating that both are intermediate metabolites in degradation. Formate accumulated and was then consumed during methanogenesis from H2-CO2. Higher concentrations of formate accumulated in the absence of sulfate than in the presence of sulfate. The addition of sulfate (8 to 9 mM) increased the maximum substrate degradation rates for propionate and ethanol by 27 and 12%, respectively. In the presence of this level of sulfate, sulfate-reducing bacteria did not play a significant role in the metabolism of H2, formate, and acetate, but ethanol and propionate were converted via sulfate reduction by approximately 28 and 60%, respectively. In the presence of 2.0 mM molybdate, syntrophic propionate and ethanol conversion by the granules was inhibited by 97 and 29%, respectively. The data show that in this granular microbial consortium, methanogens and sulfate-reducing bacteria did not compete for common substrates. Syntrophic propionate and ethanol conversion was likely performed primarily by sulfate-reducing bacteria, while H2, formate, and acetate were consumed primarily by methanogens. Images PMID:1785921

  6. 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

  7. Studies on dissimilatory sulfate-reducing bacteria that decompose fatty acids

    Microsoft Academic Search

    Friedrich Widdel; Norbert Pfennig

    1981-01-01

    Three strains (2ac9, 3ac10 and 4ac11) of oval to rodshaped, Gram negative, nonsporing sulfate-reducing bacteria were isolated from brackish water and marine mud samples with acetate as sole electron donor. All three strains grew in simple defined media supplemented with biotin and 4-aminobenzoic acid as growth factors. Acetate was the only electron donor utilized by strain 2ac9, while the other

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

    Microsoft Academic Search

    Satoshi Okabe; Tsukasa Itoh; Hisashi Satoh; Yoshimasa Watanabe

    1999-01-01

    The vertical distribution of sulfate-reducing bacteria (SRB) in aerobic wastewater biofilms grown on rotating disk reactors was investigated by fluorescent in situ hybridization (FISH) with 16S rRNA-targeted oligonucleotide probes. To correlate the vertical distribution of SRB populations with their activity, the microprofiles of Oâ, HâS, NOâ-, NHâ{sup +}, and pH were measured with microelectrodes. In addition, a cross-evaluation of the

  9. Formation of Sphalerite (ZnS) Deposits in Natural Biofilms of Sulfate-Reducing Bacteria

    Microsoft Academic Search

    Matthias Labrenz; Gregory K. Druschel; Tamara Thomsen-Ebert; Benjamin Gilbert; Susan A. Welch; Kenneth M. Kemner; Graham A. Logan; Roger E. Summons; Gelsomina De Stasio; Philip L. Bond; Barry Lai; Shelly D. Kelly; Jillian F. Banfield; Diversions Scuba

    2000-01-01

    Abundant, micrometer-scale, spherical aggregates of 2- to 5-nanometer-diameter sphalerite (ZnS) particles formed within natural biofilms dominated by relatively aerotolerant sulfate-reducing bacteria of the family Desulfobacteriaceae. The biofilm zinc concentration is about 106 times that of associated groundwater (0.09 to 1.1 parts per million zinc). Sphalerite also concentrates arsenic (0.01 weight %) and selenium (0.004 weight %). The almost monomineralic product

  10. Development of oligonucleotide probes and PCR primers for detecting phylogenetic subgroups of sulfate-reducing bacteria

    Microsoft Academic Search

    Kristian Daly; Richard J. Sharp; Alan J. McCarthy

    2000-01-01

    PCR primer sets for the 16S rRNA gene of six phylogenetic groups of sulfate- reducing bacteria (SRB) were designed. Their application in conjunction with group-specific internal oligonucleotide probes was used to detect SRB DNA in samples of landfill leachate. Six generic\\/suprageneric groups could be differentiated : Desulfotomaculum ; Desulfobulbus; Desulfobacterium ; Desulfobacter; Desulfococcus-Desulfonema-Desulfosarcina; Desulfovibrio-Desulfomicrobium. The predicted specificities of the PCR

  11. Molecular phylogenetic and biogeochemical studies of sulfate-reducing bacteria in the rhizosphere of Spartina alterniflora

    Microsoft Academic Search

    MARK E. HINES; ROBERT S. EVANS; S. G. Willis; J. N. Rooney-Varga; B. R. S. Genthner; S. Friedman; RICHARD DEVEREUX

    1999-01-01

    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 by molecular probing, enumerations of culturable SRB, and measurements of SOâ²⁻ reduction rates and geochemical parameters. Soâ²⁻ reduction was rapid in marsh sediments with rates up to 3.5 μmol ml⁻¹ day⁻¹. Rates increased greatly when plant

  12. Evaluation of the semisolid Postgate's B medium for enumerating sulfate-reducing bacteria

    Microsoft Academic Search

    Devender K. Jain

    1995-01-01

    Traditionally, sulfate-reducing bacteria (SRB) in environmental samples are enumerated by serial dilution in completely anaerobic liquid media which require time consuming anaerobic techniques for media preparation, inoculation and incubation. Moreover, an incubation time of up to 28 days is recommended for SRB enumeration. In the technique described in this paper, Postgate's B liquid medium was amended with 1.5 g l?1

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

    Microsoft Academic Search

    YUN-JUAN CHANG; AARON D. PEACOCK; PHILIP E. LONG; JOHN R. STEPHEN; JAMES P. MCKINLEY; SARAH J. MACNAUGHTON; A. K. M. A. Hussain; ARNOLD M. SAXTON; DAVID C. WHITE

    2001-01-01

    Microbially mediated reduction and immobilization of U(VI) to U(IV) plays a role in both natural attenu- ation 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

  14. 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

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

    PubMed Central

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

    1991-01-01

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

  16. Promotion of Ni2+ removal by masking toxicity to sulfate-reducing bacteria: addition of citrate.

    PubMed

    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

  17. 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.

  18. 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.

  19. 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.

  20. Oil field souring control by nitrate-reducing Sulfurospirillum spp. that outcompete sulfate-reducing bacteria for organic electron donors.

    PubMed

    Hubert, Casey; Voordouw, Gerrit

    2007-04-01

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

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

    PubMed Central

    Hubert, Casey; Voordouw, Gerrit

    2007-01-01

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

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

    SciTech Connect

    Enos, D.G.; Taylor, S.R. [Univ. of Virginia, Charlottesville, VA (United States)

    1996-11-01

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

  3. Electron Donors Utilized by Sulfate-Reducing Bacteria in Eutrophic Lake Sediments †

    PubMed Central

    Smith, Richard L.; Klug, Michael J.

    1981-01-01

    Mineralization rates of 14C-labeled substrates were determined in the presence and absence of Na2MoO4, an inhibitor of sulfate reduction, in the profundal sediments of a shallow eutrophic lake. Sulfate reduction was inhibited by Na2MoO4 at all concentrations tested (0.2 to 200 mM), whereas methane production was inhibited at Na2MoO4 concentrations greater than 20 mM. Initial mineralization rates of glucose were unaffected by Na2MoO4; however, Na2MoO4 decreased the mineralization rates of lactate (58%), propionate (52%), an amino acid mixture (85%), and acetate (14%). These decreases in the rates of mineralization were attributed to inhibition of sulfate reduction. Hydrogen stimulated the reduction of 35SO42? 2.5- to 2.8-fold, demonstrating potential hydrogen oxidation by sulfate-reducing bacteria. These results indicate that sulfate reducers utilize an array of substrates as electron donors and are of potential significance to the in situ mineralization of lactate, propionate, and free amino acids in these sediments. PMID:16345804

  4. Comparative Analysis of Methane-Oxidizing Archaea and Sulfate-Reducing Bacteria in Anoxic Marine Sediments

    PubMed Central

    Orphan, V. J.; Hinrichs, K.-U.; Ussler, W.; Paull, C. K.; Taylor, L. T.; Sylva, S. P.; Hayes, J. M.; Delong, E. F.

    2001-01-01

    The oxidation of methane in anoxic marine sediments is thought to be mediated by a consortium of methane-consuming archaea and sulfate-reducing bacteria. In this study, we compared results of rRNA gene (rDNA) surveys and lipid analyses of archaea and bacteria associated with methane seep sediments from several different sites on the Californian continental margin. Two distinct archaeal lineages (ANME-1 and ANME-2), peripherally related to the order Methanosarcinales, were consistently associated with methane seep marine sediments. The same sediments contained abundant 13C-depleted archaeal lipids, indicating that one or both of these archaeal groups are members of anaerobic methane-oxidizing consortia. 13C-depleted lipids and the signature 16S rDNAs for these archaeal groups were absent in nearby control sediments. Concurrent surveys of bacterial rDNAs revealed a predominance of ?-proteobacteria, in particular, close relatives of Desulfosarcina variabilis. Biomarker analyses of the same sediments showed bacterial fatty acids with strong 13C depletion that are likely products of these sulfate-reducing bacteria. Consistent with these observations, whole-cell fluorescent in situ hybridization revealed aggregations of ANME-2 archaea and sulfate-reducing Desulfosarcina and Desulfococcus species. Additionally, the presence of abundant 13C-depleted ether lipids, presumed to be of bacterial origin but unrelated to ether lipids of members of the order Desulfosarcinales, suggests the participation of additional bacterial groups in the methane-oxidizing process. Although the Desulfosarcinales and ANME-2 consortia appear to participate in the anaerobic oxidation of methane in marine sediments, our data suggest that other bacteria and archaea are also involved in methane oxidation in these environments. PMID:11282650

  5. Diversity, Activity, and Abundance of Sulfate-Reducing Bacteria in Saline and Hypersaline Soda Lakes?

    PubMed Central

    Foti, Mirjam; Sorokin, Dimitry Y.; Lomans, Bart; Mussman, Marc; Zacharova, Elena E.; Pimenov, Nikolay V.; Kuenen, J. Gijs; Muyzer, Gerard

    2007-01-01

    Soda lakes are naturally occurring highly alkaline and saline environments. Although the sulfur cycle is one of the most active element cycles in these lakes, little is known about the sulfate-reducing bacteria (SRB). In this study we investigated the diversity, activity, and abundance of SRB in sediment samples and enrichment cultures from a range of (hyper)saline soda lakes of the Kulunda Steppe in southeastern Siberia in Russia. For this purpose, a polyphasic approach was used, including denaturing gradient gel electrophoresis of dsr gene fragments, sulfate reduction rate measurements, serial dilutions, and quantitative real-time PCR (qPCR). Comparative sequence analysis revealed the presence of several novel clusters of SRB, mostly affiliated with members of the order Desulfovibrionales and family Desulfobacteraceae. We detected sulfate reducers and observed substantial sulfate reducing rates (between 12 and 423 ?mol/dm3 day?1) for most lakes, even at a salinity of 475 g/liter. Enrichments were obtained at salt saturating conditions (4 M Na+), using H2 or volatile fatty acids as electron donors, and an extremely halophilic SRB, strain ASO3-1, was isolated. Furthermore, a high dsr gene copy number of 108 cells per ml was detected in a hypersaline lake by qPCR. Our results indicate the presence of diverse and active SRB communities in these extreme ecosystems. PMID:17308191

  6. Competition and coexistence of sulfate-reducing bacteria, acetogens and methanogens in a lab-scale anaerobic bioreactor as affected by changing substrate to sulfate ratio

    PubMed Central

    Dar, Shabir A.; Kleerebezem, Robbert; Stams, Alfons J. M.; Kuenen, J. Gijs

    2008-01-01

    The microbial population structure and function of natural anaerobic communities maintained in lab-scale continuously stirred tank reactors at different lactate to sulfate ratios and in the absence of sulfate were analyzed using an integrated approach of molecular techniques and chemical analysis. The population structure, determined by denaturing gradient gel electrophoresis and by the use of oligonucleotide probes, was linked to the functional changes in the reactors. At the influent lactate to sulfate molar ratio of 0.35 mol mol?1, i.e., electron donor limitation, lactate oxidation was mainly carried out by incompletely oxidizing sulfate-reducing bacteria, which formed 80–85% of the total bacterial population. Desulfomicrobium- and Desulfovibrio-like species were the most abundant sulfate-reducing bacteria. Acetogens and methanogenic Archaea were mostly outcompeted, although less than 2% of an acetogenic population could still be observed at this limiting concentration of lactate. In the near absence of sulfate (i.e., at very high lactate/sulfate ratio), acetogens and methanogenic Archaea were the dominant microbial communities. Acetogenic bacteria represented by Dendrosporobacter quercicolus-like species formed more than 70% of the population, while methanogenic bacteria related to uncultured Archaea comprising about 10–15% of the microbial community. At an influent lactate to sulfate molar ratio of 2 mol mol?1, i.e., under sulfate-limiting conditions, a different metabolic route was followed by the mixed anaerobic community. Apparently, lactate was fermented to acetate and propionate, while the majority of sulfidogenesis and methanogenesis were dependent on these fermentation products. This was consistent with the presence of significant levels (40–45% of total bacteria) of D. quercicolus-like heteroacetogens and a corresponding increase of propionate-oxidizing Desulfobulbus-like sulfate-reducing bacteria (20% of the total bacteria). Methanogenic Archaea accounted for 10% of the total microbial community. PMID:18305937

  7. 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.

  8. 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.

  9. 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.

  10. Contribution of enrichments and resampling for sulfate reducing bacteria diversity assessment by high-throughput cultivation.

    PubMed

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

    2015-03-01

    The development of new high-throughput cultivation methods aims to increase the isolation efficiency as compared to standard techniques that often require enrichment procedures to compensate the low microbial recovery. In the current study, estuarine sulfate-reducing bacteria were isolated using an anaerobic isolation procedure in 384-well microplates. Ninety-nine strains were recovered from initial sediments. Isolates were identified according to their partial 16S rRNA sequences and clustered into 13 phylotypes. Besides, the increase in species richness obtained through enrichments or resampling was investigated. Forty-four enrichment procedures were conducted and shifts in sulfate-reducing bacterial communities were investigated through dsrAB gene fingerprinting. Despite efforts in conducting numerous enrichment conditions only few of them were statistically different from initial sample. The cultural diversity obtained from 3 of the most divergent enrichments, as well as from resampled sediments equally contributed to raise the sulfate-reducing diversity up to 22 phylotypes. Enrichments (selection of metabolism) or resampling (transient populations and micro-heterogeneity) may still be helpful to assess new microbial phylotypes. Nevertheless, all the newly cultivated strains were all representatives of minor Operational Taxonomic Units and could eventually be recovered by maintaining high-throughput isolation effort from the initial sediments. PMID:25578508

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

    PubMed

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

    2014-02-28

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

  12. Reduction of chromate by fixed films of sulfate-reducing bacteria using hydrogen as an electron source

    Microsoft Academic Search

    F Battaglia-Brunet; S Foucher; A Denamur; I Ignatiadis; C Michel; D Morin

    2002-01-01

    The ability of sulfate-reducing bacteria (SRB) to reduce chromate, Cr(VI), was evaluated using fixed-film growth systems and H2 as the electron source. A main objective of the experiment was to distinguish between direct enzymatic reduction and indirect reduction by hydrogen sulfide, in order to subsequently verify and control the synergy of these two mechanisms. In batch experiments with the sulfate-reducing

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

    EPA Science Inventory

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

  14. 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.

  15. Experimental investigation on the active range of sulfate-reducing bacteria for geological disposal

    SciTech Connect

    Fukunaga, S.; Fujiki, K.; Asano, H. [Ishikawajima-Harima Heavy Industries Co., Ltd., Yokohama (Japan); Yoshikawa, H. [Power Reactor and Nuclear Fuel Development Corp., Tokai, Ibaraki (Japan)

    1995-12-31

    The active range of Desulfovibrio desulfuricans, a species of sulfate-reducing bacteria, was examined in terms of pH and Eh using a fermenter at controlled pH and Eh. Such research is important because sulfate-reducing bacteria (SRB) are thought to exist underground at depths equal to those of supposed repositories for high-level radioactive wastes and to be capable of inducing corrosion of the metals used in containment vessels. SRB activity was estimated at 35 C, with lactate as an electron donor, at a pH range from 7 to 11 and Eh range from 0 to {minus}380 mV. Activity increased as pH approached neutral and Eh declined. The upper pH limit for activity was between 9.9 and 10.3, at Eh of {minus}360 to {minus}384 mV. The upper Eh limit for activity was between {minus}68 and {minus}3 mV, at pH 7.1. These results show that SRB can be made active at higher pH by decreasing Eh, and that the higher pH levels of 8 to 10 produced by use of the buffer material bentonite does not suppress SRB completely. A chart was obtained showing the active range of Desulfovibrio desulfuricans in terms of pH and Eh. Such charts can be used to estimate the viability of SRB and other microorganisms when the environmental conditions of a repository are specified.

  16. 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

  17. 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

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

    PubMed

    Kushkevych, Ivan V

    2015-01-01

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

  19. Enzymatic reduction of chromate: comparative studies using sulfate-reducing bacteria. Key role of polyheme cytochromes c and hydrogenases.

    PubMed

    Michel, C; Brugna, M; Aubert, C; Bernadac, A; Bruschi, M

    2001-01-01

    Various sulfate-reducing bacteria of the genera Desulfovibrio and Desulfomicrobium were tested and compared for enzymatic reduction of chromate. Our study demonstrated that the ability to reduce chromate is widespread among sulfate-reducing bacteria. Among them, Desulfomicrobium norvegicum reduced Cr(VI) with the highest reaction rate. This strain grew in the presence of up to 500 microM chromate, but Cr(VI) reduction in the absence of sulfate was not associated with growth. The presence of chromate induced morphological changes and leakage of periplasmic proteins into the medium. The ability of isolated polyheme cytochromes c from sulfate- and sulfur-reducing bacteria to reduce chromate was also analyzed. Tetraheme cytochrome c3(Mr. 13,000) from Desulfomicrobium norvegicum showed twice as much activity as either tetraheme cytochrome c3 from Desulfovibrio vulgaris strain Hildenborough or triheme cytochrome c7 from Desulfuromonas acetoxidans. Results with cytochromes c3 and other c-type cytochromes altered by site-directed mutagenesis indicated that negative redox potential hemes are crucial for metal reductase activity. The present study also demonstrated that the (Fe) hydrogenase from sulfate-reducing bacteria could reduce chromate. PMID:11234966

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

    SciTech Connect

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

    1986-10-01

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

  1. (The genetics and molecular biology of hydrogen metabolism in sulfate-reducing bacteria): Progress report

    SciTech Connect

    Not Available

    1988-12-01

    In anaerobic digestors and natural environments, the sulfate-reducing bacteria (SRB) play a pivotal role in methane generation, either providing hydrogen and acetate for methane formation or competing with the methanogens for those same substrates. The SRB are also the primary culprits in causing environmental metal corrosion costing millions of dollars each year and in producing poisonous sulfide sometimes costing lives. Key factors controlling the interactions of the SRB with other microorganisms in their environment are hydrogen metabolism and their tolerance of exposures to oxygen. The number of enzymes capable of producing or consuming hydrogen in the SRB and their physiological functions remain obscure. Our laboratory is developing the genetics and molecular biology of the SRB with the aim of examining the hydrogen metabolism. Desulfovibrio desulfuricans ATCC 27774 has been found to be amenable to classical genetic manipulation, antibiotic resistant mutants as well as mutants altered in sulfate and hydrogen metabolism have been isolated. Most excitingly, this strain has been found to produce a defective bacteriophage capable of generalized transduction. This strain as well as G100A have been found to be capable of genetic exchange with Escherichia coli via conjugation involving Q-incompatibility group plasmids. Detailed examination of the metabolic properties of these bacteria is now possible.

  2. Reduction of Hexavalent Uranium from Organic Complexes by Sulfate- and Iron-Reducing Bacteria

    PubMed Central

    Ganesh, R.; Robinson, K. G.; Reed, G. D.; Sayler, G. S.

    1997-01-01

    The influence of organic-hexavalent-uranium [U(VI)] complexation on U(VI) reduction by a sulfate-reducing bacterium (Desulfovibrio desulfuricans) and an iron-reducing bacterium (Shewanella alga) was evaluated. Four aliphatic ligands (acetate, malonate, oxalate, and citrate) and an aromatic ligand (tiron [4,5-dihydroxy-1,3-benzene disulfonic acid]) were used to study complexed-uranium bioavailability. The trends in uranium reduction varied with the nature and the amount of U(VI)-organic complex formed and the type of bacteria present. D. desulfuricans rapidly reduced uranium from a monodentate aliphatic (acetate) complex. However, reduction from multidentate aliphatic complexes (malonate, oxalate, and citrate) was slower. A decrease in the amount of organic-U(VI) complex in solution significantly increased the rate of reduction. S. alga reduced uranium more rapidly from multidentate aliphatic complexes than from monodentate aliphatic complexes. The rate of reduction decreased with a decrease in the amount of multidentate complexes present. Uranium from an aromatic (tiron) complex was readily available for reduction by D. desulfuricans, while an insignificant level of U(VI) from the tiron complex was reduced by S. alga. These results indicate that selection of bacteria for rapid uranium reduction will depend on the organic composition of waste streams. PMID:16535729

  3. 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.

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

    PubMed

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

    2013-10-01

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

  5. 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

  6. 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.

  7. 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 ?(202)Hg), but insignificant mass-independent fractionation (MIF) (-0.12 to +0.15‰ for ?(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 ?(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

  8. Biochemical control of sulfide generated by sulfate-reducing bacteria in an industrial waste treatment system

    SciTech Connect

    Russell, G.L.; Britton, L.N. [Vista Chemical Co., Austin, TX (United States)

    1994-12-31

    Hydrogen sulfide production by sulfate-reducing bacteria (SRB) is common in non-aerated, upstream, equalization tanks that receive process wastewater prior to aerobic treatment. This phenomenon results in increased oxygen demand in the aerobic basin and problems with deposition of metal sulfides. The objective of this research was to develop a method for sulfide control without the use of biocides or release of volatile organics upstream of the treatment basin via sparging to maintain inhibitory levels of dissolved oxygen. Specifically, the addition of nitrate to competitively decrease SRB activity by shifting the microbial activity towards nitrate reduction was evaluated in bench-scale reactors. This shift was found to be favorable as a pretreatment for oxidation of organics in advance of the aerobic treatment process. The addition of nitrate while maintaining low dissolved oxygen had the same effect as a sequenced anaerobic/aerobic treatment process in the removal of organics, yet there were no problems with sulfide generation.

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

    SciTech Connect

    Campaignolle, X. [Univ. de Bordeaux 1, Arcachon (France). Lab. d`Oceanographie Biologique; Crolet, J.L. [Elf Aquitaine, Pau (France)

    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.

  10. 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.

  11. 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 ?m. 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

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

    PubMed

    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 ?m. Analysis of a 16S rRNA gene library, followed by whole-cell hybridization with group- and sequence-specific oligonucleotide probes showed that these cells belonged to a single phylotype, and were accounting for more than 80% of the total cell number. The dominant phylotype, affiliated with the Desulfosarcina-Desulfococcus cluster of the Deltaproteobacteria, is proposed to be responsible for the degradation of cyclohexane. Quantitative growth experiments showed that cyclohexane degradation was coupled with the stoichiometric reduction of sulfate to sulfide. Substrate response tests corroborated with hybridization with a sequence-specific oligonucleotide probe suggested that the dominant phylotype apparently was able to degrade other cyclic and n-alkanes, including the gaseous alkane n-butane. Based on GC-MS analyses of culture extracts cyclohexylsuccinate was identified as a metabolite, indicating an activation of cyclohexane by addition to fumarate. Other metabolites detected were 3-cyclohexylpropionate and cyclohexanecarboxylate providing evidence that the overall degradation pathway of cyclohexane under anoxic conditions is analogous to that of n-alkanes. PMID:25806023

  13. Molecular phylogenetic and biogeochemical studies of sulfate-reducing bacteria in the rhizosphere of Spartina alterniflora

    SciTech Connect

    Hines, M.E. [Univ. of Alaska, Anchorage, AK (United States). Dept. of Biological Sciences; Evans, R.S.; Willis, S.G.; Rooney-Varga, J.N. [Univ. of New Hampshire, Durham, NH (United States). Inst. for the Study of Earth, Oceans and Space; Genthner, B.R.S. [Univ. of West Florida, Pensacola, FL (United States). Center for Environmental Diagnostics and Bioremediation; Friedman, S.; Devereux, R. [Environmental Protection Agency, Gulf Breeze, FL (United States). National Health and Environmental Effects Research Lab.

    1999-05-01

    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 by molecular probing, enumerations of culturable SRB, and measurements of SO{sub 4}{sup 2{minus}} reduction rates and geochemical parameters. So{sub 4}{sup 2{minus}} reduction was rapid in marsh sediments with rates up to 3.5 {micro}mol ml{sup {minus}1} day{sup {minus}1}. Rates increased greatly when plant growth began in April and decreased again when plants flowered in late July. Results with nucleic acid probes revealed that SRB rRNA accounted for up to 43% of the rRNA from members of the domain Bacteria in marsh sediments, with the highest percentages occurring in bacteria physically associated with root surfaces. The relative abundance (RA) of SRB rRNA in whole-sediment samples compared to that of Bacteria rRNA did not vary greatly throughout the year, despite large temporal changes in SO{sub 4}{sup 2{minus}} reduction activity. However, the RA of root-associated SRB did increase from < 10 to > 30% when plants were actively growing. rRNA from members of the family Desulfobacteriaceae comprised the majority of the SRB rRNA at 3 to 34% of Bacteria rRNA, with Desulfobulbus spp. accounting for 1 to 16%. The RA of Desulfovibrio rRNA generally comprised from < 1 to 3% of the Bacteria rRNA. The highest Desulfobacteriaceae RA in whole sediments was 26% and was found in the deepest sediment samples (6 to 8 cm). Culturable SRB abundance, determined by most-probable-number analyses, was high at > 10{sup 7} ml{sup {minus}1}. Ethanol utilizers were most abundant, followed by acetate utilizers. The high numbers of culturable SRB and the high RA of SRB rRNA compared to that of Bacteria rRNA may be due to the release of SRB substrates in plant root exudates, creating a microbial food web that circumvents fermentation.

  14. Importance of sulfate reducing bacteria in mercury methylation and demethylation in periphyton from Bolivian Amazon region.

    PubMed

    Achá, Darío; Hintelmann, Holger; Yee, Janet

    2011-02-01

    Sulfate reducing bacteria (SRB) are important mercury methylators in sediments, but information on mercury methylators in other compartments is ambiguous. To investigate SRB involvement in methylation in Amazonian periphyton, the relationship between Hg methylation potential and SRB (Desulfobacteraceae, Desulfobulbaceae and Desulfovibrionaceae) abundance in Eichhornia crassipes and Polygonum densiflorum root associated periphyton was examined. Periphyton subsamples of each macrophyte were amended with electron donors (lactate, acetate and propionate) or inhibitors (molybdate) of sulfate reduction to create differences in SRB subgroup abundance, which was measured by quantitative real-time PCR with primers specific for the 16S rRNA gene. Mercury methylation and demethylation potentials were determined by a stable isotope tracer technique using 200HgCl and CH3(202)HgCl, respectively. Relative abundance of Desulfobacteraceae (<0.01-12.5%) and Desulfovibrionaceae (0.01-6.8%) were both highly variable among samples and subsamples, but a significant linear relationship (p<0.05) was found between Desulfobacteraceae abundance and net methylmercury formation among treatments of the same macrophyte periphyton and among all P. densiflorum samples, suggesting that Desulfobacteraceae bacteria are the most important mercury methylators among SRB families. Yet, molybdate only partially inhibited mercury methylation potentials, suggesting the involvement of other microorganisms as well. The response of net methylmercury production to the different electron donors and molybdate was highly variable (3-1104 pg g(-1) in 12 h) among samples, as was the net formation in control samples (17-164 pg g(-1) in 12 h). This demonstrates the importance of community variability and complexity of microbial interactions for the overall methylmercury production in periphyton and their response to external stimulus. PMID:21074243

  15. 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.

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

    EPA Science Inventory

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

  17. 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.

  18. 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...

  19. Sulfur isotropic studies of Archean slate and graywacke from northern Minnesota: Evidence for the existence of sulfate reducing bacteria

    Microsoft Academic Search

    E. M. Ripley; D. L. Nicol

    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

  20. Phototropic sulfur and sulfate-reducing bacteria in the chemocline of meromictic Lake Cadagno, Switzerland

    Microsoft Academic Search

    Mauro TONOLLA; Sandro PEDUZZI; Antonella DEMARTA; Raffaele PEDUZZI; Dittmar HAHN

    Lake Cadagno, a crenogenic meromictic lake located in the catchment area of a dolomite vein rich in gypsum in the Piora Valley in the southern Alps of Switzerland, is characterized by a compact chemocline with high concentrations of sulfate, steep gradients of oxygen, sulfide and light and a turbidity maximum that correlates to large numbers of bacteria (up to 107

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

    PubMed

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

    2012-07-01

    Iron (Fe(0) ) 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 H(2) S, and scavenge of 'cathodic' H(2) from chemical reaction of Fe(0) with H(2) O. 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?Fe(0) year(-1) ), while conventional H(2) -scavenging control strains were not corrosive. The black, hard mineral crust (FeS, FeCO(3) , Mg/CaCO(3) ) 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 (4Fe(0) ???4Fe(2+) ?+?8e(-) ) through semiconductive sulfides to the crust-colonizing cells reducing sulfate (8e(-) ?+?SO(4) (2-) ?+?9H(+) ???HS(-) ?+?4H(2) O). Hence, anaerobic microbial iron corrosion obviously bypasses H(2) 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

  2. 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

  3. 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

  4. 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.

  5. 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.

  6. 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

  7. 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

  8. Methylmercury and sulfate-reducing bacteria in mangrove sediments from Jiulong River Estuary, China.

    PubMed

    Wu, Hao; Ding, Zhenhua; Liu, Yang; Liu, Jinling; Yan, Haiyu; Pan, Jiayong; Li, Liuqiang; Lin, Huina; Lin, Guanghui; Lu, Haoliang

    2011-01-01

    Estuaries are important sites for mercury (Hg) methylation, with sulfate-reducing bacteria (SRB) thought to be the main Hg methylators. Distributions of total mercury (THg) and methylmercury (MeHg) in mangrove sediment and sediment core from Jiulong River Estuary Provincial Mangrove Reserve, China were determined and the possible mechanisms of Hg methylation and their controlling factors in mangrove sediments were investigated. Microbiological and geochemical parameters were also determined. Results showed that SRB constitute a small fraction of total bacteria (TB) in both surface sediments and the profile of sediments. The content of THg, MeHg, TB, and SRB were (350 +/- 150) ng/g, (0.47 +/- 0.11) ng/g, (1.4 x10(11) +/- 4.1 x 10(9)) cfu/g dry weight (dw), and (5.0 x 10(6) +/- 2.7 x 10(6)) cfu/g dw in surficial sediments, respectively, and (240 +/- 24) ng/g, (0.30 +/- 0.15) ng/g, (1.9 x 10(11) +/- 4.2 x 10(10)) cfu/g dw, and (1.3 x 10(6) +/- 2.0 x 10(6)) cfu/g dw in sediment core, respectively. Results showed that THg, MeHg, TB, MeHg/THg, salinity and total sulfur (TS) increased with depth, but total organic matter (TOM), SRB, and pH decreased with depth. Concentrations of MeHg in sediments showed significant positive correlation with THg, salinity, TS, and MeHg/THg, and significant negative correlation with SRB, TOM, and pH. It was concluded that other microbes, rather than SRB, may also act as main Hg methylators in mangrove sediments. PMID:21476335

  9. 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

  10. Long-term surveillance of sulfate-reducing bacteria in highly saline industrial wastewater evaporation ponds

    PubMed Central

    Ben-Dov, Eitan; Kushmaro, Ariel; Brenner, Asher

    2009-01-01

    Abundance and seasonal dynamics of sulfate-reducing bacteria (SRB), in general, and of extreme halophilic SRB (belonging to Desulfocella halophila) in particular, were examined in highly saline industrial wastewater evaporation ponds over a forty one month period. Industrial wastewater was sampled and the presence of SRB was determined by quantitative real-time PCR (qPCR) with a set of primers designed to amplify the dissimilatory sulfite reductase (dsrA) gene. SRB displayed higher abundance during the summer (106–108 targets ml-1) and lower abundance from the autumn-spring (103–105 targets ml-1). However, addition of concentrated dissolved organic matter into the evaporation ponds during winter immediately resulted in a proliferation of SRB, despite the lower wastewater temperature (12–14°C). These results indicate that the qPCR approach can be used for rapid measurement of SRB to provide valuable information about the abundance of SRB in harsh environments, such as highly saline industrial wastewaters. Low level of H2S has been maintained over five years, which indicates a possible inhibition of SRB activity, following artificial salination (?16% w/v of NaCl) of wastewater evaporation ponds, despite SRB reproduction being detected by qPCR. PMID:19226456

  11. A study on the potential of metal corrosion by sulfate-reducing bacteria in animal buildings

    SciTech Connect

    Zhu, J.; Riskowski, G.L.; Mackie, R.I.

    1999-06-01

    The potential of sulfate-reducing bacteria (SRB) to cause metal corrosion in animal buildings was examined in this study. An analysis was done on the bacterial colonization and the corrosion products on the surfaces of metals exposed to three animal buildings and one environmentally controlled building over a two-year period. Data from this study showed that the levels of SRB on metal surfaces were low after two-year's exposure (maximum count: 1.7 x 10{sup 4}/cm{sup 2}). SRB colonization levels after two years were not sufficient to corrode metal products exposed in animal environments. In addition, metal surface analysis data using X-ray photoelectron spectroscopy showed that the corrosion compounds formed on the surfaces of different metals were not due to the SERB-induced corrosion mechanisms. These compounds were mainly oxides and carbonates (FeO, Fe{sub 2}O{sub 3}, Fe{sub 3}O{sub 4}, and Fe(CO){sub 5} on iron samples; ZnO and ZnCO{sub 3} on galvanized steel samples: Al{sub 2}O{sub 3}, ZnO, and ZnCO{sub 3} on Galvalume samples), and were normally generated due to the classic types of corrosion mechanisms. Some sulfur was present to form ZnS on the galvanized steel samples, but might not be attributed to SRB. The origin of this sulfur was not clear.

  12. Influence of sulfate-reducing bacteria on the passivity of type 304 austenitic stainless steel

    SciTech Connect

    Chen, G.; Clayton, C.R. [State Univ. of New York, Stony Brook, NY (United States). Dept. of Materials Science and Engineering

    1997-09-01

    The influence of sulfate-reducing bacteria (SRB) on the passivity of type 304 austenitic stainless steel was investigated using x-ray photoelectron spectroscopy (XPS) and electrochemical techniques. Multiple samples were exposed to a SRB culture, Desulfovibrio desulfuricans, and then resultant changes in the surface states were determined by XPS and in the corrosion resistance by potentiodynamic polarization in deaerated 0.1 M HCl. Furthermore, the SRB-exposed samples were anodically polarized at a passive potential ({minus}160 mV{sub SCE}) in 0.1 M HCl and subsequently analyzed by XPS. The electrochemical and XPS analyses were performed under two surface conditions, unrinsed with the biofilm and rinsed. Formation of sulfides and thermodynamically unstable products during exposure to SRB caused loss of the steel passivity. The following sulfides were observed: FeS, FeS{sub 2}, NiS, Cr{sub 2}S{sub 3}, and possibly Fe{sub 1{minus}x}S. The unstable products included FeO and hexavalent chromium (Cr{sup 6+}) species. The sulfides unevenly distributed in the depth of the passive film so that undercutting took place, rendering a higher degree of hydration of the inner layers of the passive film. The loss of passivity, measured by the polarization current density, was proportional to the extent of undercutting of the passive film and the relative proportion of the Cr{sup 6+} species.

  13. 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.

  14. A Study of the Relative Dominance of Selected Anaerobic Sulfate-Reducing Bacteria in a Continuous Bioreactor by Fluorescence in Situ Hybridization

    Microsoft Academic Search

    B. Icgen; S. Moosa; S. T. L. Harrison

    2007-01-01

    The diversity and the community structure of sulfate-reducing bacteria (SRB) in an anaerobic continuous bioreactor used for\\u000a treatment of a sulfate-containing wastewater were investigated by fluorescence in situ hybridization. Hybridization to the 16S rRNA probe EUB338 for the domain Bacteria was performed, followed by a nonsense probe\\u000a NON338 as a control for nonspecific staining. Sulfate-reducing consortia were identified by using

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

    SciTech Connect

    Petersen, T.A.; Taylor, S.R. [Univ. of Virginia, Charlottesville, VA (United States). Center for Electrochemical Science and Engineering

    1995-10-01

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

  16. Long-term competition between sulfate reducing and methanogenic bacteria in UASB reactors treating volatile fatty acids

    SciTech Connect

    Omil, F. [Agricultural Univ. of Wageningen (Netherlands). Dept. of Environmental Technology] [Agricultural Univ. of Wageningen (Netherlands). Dept. of Environmental Technology; [Univ. of Santiago de Compostela (Spain). Dept. of Chemical Engineering; Lens, P.; Visser, A.; Hulshoff Pol, L.W.; Lettinga, G. [Agricultural Univ. of Wageningen (Netherlands). Dept. of Environmental Technology] [Agricultural Univ. of Wageningen (Netherlands). Dept. of Environmental Technology

    1998-03-20

    The competition between acetate utilizing methane-producing bacteria (MB) and sulfate-reducing bacteria (SRB) was studied in mesophilic (30 C) upflow anaerobic sludge bed (UASB) reactors treating volatile fatty acids and sulfate. The UASB reactors treated a VFA mixture (with an acetate:propionate:butyrate ratio of 5:3:2 on COD basis) or acetate as the sole substrate at different COD:sulfate ratios. The outcome of the competition was evaluated in terms of conversion rates and specific methanogenic and sulfidogenic activities. The COD:sulfate ratio was a key factor in the partitioning of acetate utilization between MB and SRB. In excess of sulfate, SRB became predominant over MB after prolonged reactor operation: 250 and 400 days were required to increase the amount of acetate used by SRB from 50 to 90% in the reactor treating, respectively, the VFA mixture or acetate as the sole substrate. The competition for acetate was further studied by dynamic simulations using a mathematical model based on the Monod kinetic parameters of acetate utilizing SRB and MB. The simulations confirmed the long term nature of the competition between these acetotrophs. A high reactor pH ({+-}8), a short solid retention time (<150 days), and the presence of a substantial SRB population in the inoculum may considerably reduce the time required for acetate-utilizing SRB to outcompete MB.

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

    NASA Astrophysics Data System (ADS)

    Xu, H.; Barton, L. L.

    2010-12-01

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

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

    PubMed Central

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

    2001-01-01

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

  19. 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

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

    Microsoft Academic Search

    J. W. Moreau; D. P. Krabbenhoft

    2008-01-01

    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

  1. Anaerobic Oxidation of o-Xylene, m-Xylene, and Homologous Alkylbenzenes by New Types of Sulfate-Reducing Bacteria

    PubMed Central

    Harms, Gerda; Zengler, Karsten; Rabus, Ralf; Aeckersberg, Frank; Minz, Dror; Rosselló-Mora, Ramon; Widdel, Friedrich

    1999-01-01

    Various alkylbenzenes were depleted during growth of an anaerobic, sulfate-reducing enrichment culture with crude oil as the only source of organic substrates. From this culture, two new types of mesophilic, rod-shaped sulfate-reducing bacteria, strains oXyS1 and mXyS1, were isolated with o-xylene and m-xylene, respectively, as organic substrates. Sequence analyses of 16S rRNA genes revealed that the isolates affiliated with known completely oxidizing sulfate-reducing bacteria of the ? subclass of the class Proteobacteria. Strain oXyS1 showed the highest similarities to Desulfobacterium cetonicum and Desulfosarcina variabilis (similarity values, 98.4 and 98.7%, respectively). Strain mXyS1 was less closely related to known species, the closest relative being Desulfococcus multivorans (similarity value, 86.9%). Complete mineralization of o-xylene and m-xylene was demonstrated in quantitative growth experiments. Strain oXyS1 was able to utilize toluene, o-ethyltoluene, benzoate, and o-methylbenzoate in addition to o-xylene. Strain mXyS1 oxidized toluene, m-ethyltoluene, m-isoproyltoluene, benzoate, and m-methylbenzoate in addition to m-xylene. Strain oXyS1 did not utilize m-alkyltoluenes, whereas strain mXyS1 did not utilize o-alkyltoluenes. Like the enrichment culture, both isolates grew anaerobically on crude oil with concomitant reduction of sulfate to sulfide. PMID:10049854

  2. 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.

  3. Evaluation of enrichments of sulfate reducing bacteria from pristine hydrothermal vents sediments as potential inoculum for reducing trichloroethylene

    Microsoft Academic Search

    C. Guerrero-Barajas; E. I. García-Peña

    2010-01-01

    The evaluation of enrichments from pristine hydrothermal vents sediments on its capability of reducing trichloroethylene (TCE)\\u000a under sulfate reducing conditions with lactate and volatile fatty acids (VFAs) as substrates was performed. Effect of the\\u000a possible TCE biodegradation intermediates cis and trans 1,2 dichloroethenes on sulfate reduction (SR) was also evaluated. The influence of cyanocobalamin (CNB12) and riboflavin (RF) on the

  4. 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...

  5. Iron Sulfides and Sulfur Species Produced at (001) Hematite Surfaces in the Presence of Sulfate-Reducing Bacteria

    SciTech Connect

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

    2001-01-01

    In the presence of sulfate-reducing bacteria (Desulfovibrio desulfuricans) hematite (a-Fe2O3) dissolution is affected and hydrogen sulfide, the product of sulfate reduction is released. As a consequence, ferrous ions are free to react with excess H2S to form insoluble iron sulfides. X-ray photoelectron spectra indicate binding energies consistent with the iron sulfides having a pyrrhotite structure (Fe2p3/2 708.4 eV; S2p3/2 161.5 eV). Other sulfur species identified at the surface include sulfate, sulfite and polysulfides. X-ray diffraction suggests an unidentifiable crystal structure at the hematite surface develops within 3 months, HRTEM confirms the presence of a hexagonal structure again suggesting the formation of pyrrhotite. The identification of pyrrhotite is inconsistent with previous reports in which mackinawite and greigite were products of biological sulfate reduction (Rickard 1969; Herbert et al 1998). The apparent differences in stoiciometries may be related to the availability of Fe2+(aq.) at the mineral surface through respiratory iron reduction by subsurface bacteria. The significance of pyrrhotite and polysulfide production in relation to the S- and Fe-cycles and to trace metal bioavailability is discussed.

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

    PubMed

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

    2010-09-01

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

  7. 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.

  8. Inhibiting sulfate-reducing bacteria in biofilms on steel with antimicrobial peptides generated in situ

    Microsoft Academic Search

    A. Jayaraman; P. J. Hallock; R. M. Carson; C.-C. Lee; F. B. Mansfeld; T. K. Wood

    1999-01-01

    In batch and continuous fermentations, the reduction in corrosion of SAE 1018 mild steel and 304 stainless steel caused by\\u000a inhibition of the reference sulfate-reducing bacterium (SRB) Desulfovibrio vulgaris by a protective, antimicrobial-producing Bacillus brevis biofilm was investigated. The presence of D. vulgaris produced a thick black precipitate on mild steel and a higher corrosion rate in batch cultures than

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

    PubMed Central

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

    2008-01-01

    Acetate, propionate, and butyrate, collectively referred to as volatile fatty acids (VFA), are considered among the most important electron donors for sulfate-reducing bacteria (SRB) and heterotrophic nitrate-reducing bacteria (hNRB) in oil fields. Samples obtained from a field in the Neuquén Basin, western Argentina, had significant activity of mesophilic SRB, hNRB, and nitrate-reducing, sulfide-oxidizing bacteria (NR-SOB). In microcosms, containing VFA (3 mM each) and excess sulfate, SRB first used propionate and butyrate for the production of acetate, which reached concentrations of up to 12 mM prior to being used as an electron donor for sulfate reduction. In contrast, hNRB used all three organic acids with similar kinetics, while reducing nitrate to nitrite and nitrogen. Transient inhibition of VFA-utilizing SRB was observed with 0.5 mM nitrite and permanent inhibition with concentrations of 1 mM or more. The addition of nitrate to medium flowing into an upflow, packed-bed bioreactor with an established VFA-oxidizing SRB consortium led to a spike of nitrite up to 3 mM. The nitrite-mediated inhibition of SRB led, in turn, to the transient accumulation of up to 13 mM of acetate. The complete utilization of nitrate and the incomplete utilization of VFA, especially propionate, and sulfate indicated that SRB remained partially inhibited. Hence, in addition to lower sulfide concentrations, an increase in the concentration of acetate in the presence of sulfate in waters produced from an oil field subjected to nitrate injection may indicate whether the treatment is successful. The microbial community composition in the bioreactor, as determined by culturing and culture-independent techniques, indicated shifts with an increasing fraction of nitrate. With VFA and sulfate, the SRB genera Desulfobotulus, Desulfotignum, and Desulfobacter as well as the sulfur-reducing Desulfuromonas and the NR-SOB Arcobacter were detected. With VFA and nitrate, Pseudomonas spp. were present. hNRB/NR-SOB from the genus Sulfurospirillum were found under all conditions. PMID:18502934

  10. 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%.

  11. Sulfate-reducing bacteria in marine sediment (Aarhus Bay, Denmark): abundance and diversity related to geochemical zonation.

    PubMed

    Leloup, Julie; Fossing, Henrik; Kohls, Katharina; Holmkvist, Lars; Borowski, Christian; Jørgensen, Bo Barker

    2009-05-01

    In order to better understand the main factors that influence the distribution of sulfate-reducing bacteria (SRB), their population size and their metabolic activity in high- and low-sulfate zones, we studied the SRB diversity in 3- to 5-m-deep sediment cores, which comprised the entire sulfate reduction zone and the upper methanogenic zone. By combining EMA (ethidium monoazide that can only enter damaged/dead cells and may also bind to free DNA) treatment with real-time PCR, we determined the distributions of total intact bacteria (16S rDNA genes) and intact SRB (dsrAB gene), their relative population sizes, and the proportion of dead cells or free DNA with depth. The abundance of SRB corresponded in average to 13% of the total bacterial community in the sulfate zone, 22% in the sulfate-methane transition zone and 8% in the methane zone. Compared with the total bacterial community, there were relatively less dead/damaged cells and free DNA present than among the SRB and this fraction did not change systematically with depth. By DGGE analysis, based on the amplification of the dsrA gene (400 bp), we found that the richness of SRB did not change with depth through the geochemical zones; but the clustering was related to the chemical zonation. A full-length clone library of the dsrAB gene (1900 bp) was constructed from four different depths (20, 110, 280 and 500 cm), and showed that the dsrAB genes in the near-surface sediment (20 cm) was mainly composed of sequences close to the Desulfobacteraceae, including marine complete and incomplete oxidizers such as Desulfosarcina, Desulfobacterium and Desulfococcus. The three other libraries were predominantly composed of Gram-positive SRB. PMID:19220398

  12. [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

  13. 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.

  14. The behavior of sulfate-reducing bacteria in acidogenic phase of anaerobic digestion

    Microsoft Academic Search

    O. Mizuno; Y. Y. Li; T. Noike

    1998-01-01

    The effect of sulfate reduction on the acidogenic phase was investigated using anaerobic chemostat systems at 35°C. Sucrose (10,000mg COD\\/l) was used as the sole organic substrate. Chemostat systems were maintained at hydraulic retention times (HRTs) of 2, 4, 6, 8 and 10h. The sulfate concentration in the substrate was increased to 0 (control), 600, 1200 and 2400mg\\/l. Sulfate reduction

  15. 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.

  16. Sulfate-Reducing Bacteria in Tubes Constructed by the Marine Infaunal Polychaete Diopatra cuprea

    PubMed Central

    Matsui, George Y.; Ringelberg, David B.; Lovell, Charles R.

    2004-01-01

    Marine infaunal burrows and tubes greatly enhance solute transport between sediments and the overlying water column and are sites of elevated microbial activity. Biotic and abiotic controls of the compositions and activities of burrow and tube microbial communities are poorly understood. The microbial communities in tubes of the marine infaunal polychaete Diopatria cuprea collected from two different sediment habitats were examined. The bacterial communities in the tubes from a sandy sediment differed from those in the tubes from a muddy sediment. The difference in community structure also extended to the sulfate-reducing bacterial (SRB) assemblage, although it was not as pronounced for this functional group of species. PCR-amplified 16S rRNA gene sequences recovered from Diopatra tube SRB by clonal library construction and screening were all related to the family Desulfobacteriaceae. This finding was supported by phospholipid fatty acid analysis and by hybridization of 16S rRNA probes specific for members of the genera Desulfosarcina, Desulfobacter, Desulfobacterium, Desulfobotulus, Desulfococcus, and Desulfovibrio and some members of the genera Desulfomonas, Desulfuromonas, and Desulfomicrobium with 16S rRNA gene sequences resolved by denaturing gradient gel electrophoresis. Two of six SRB clones from the clone library were not detected in tubes from the sandy sediment. The habitat in which the D. cuprea tubes were constructed had a strong influence on the tube bacterial community as a whole, as well as on the SRB assemblage. PMID:15574900

  17. The influence of sulfate-reducing bacteria on the passivity of type 317L austenitic stainless steel

    SciTech Connect

    Chen, G.; Clayton, C.R. [State Univ. of New York, Stony Brook, NY (United States). Dept. of Materials Science and Engineering

    1998-06-01

    The influence of sulfate-reducing bacteria (SRB) on the passivity of a Mo-bearing austenitic stainless steel (SS), type 317L, was investigated using X-ray photoelectron spectroscopy (XPS) and electrochemical techniques. Samples were exposed to a SRB culture, and then resultant surface states were analyzed by XPS and corrosion resistance by cyclic polarization in deaerated 0.1 M HCl. Passivity of the SRB-exposed samples was further studied by XPS after polarization at a passive potential ({minus}160 mV{sub SCE}) in 0.1 M HCl. The samples were characterized under two surface conditions: unrinsed and rinsed with deaerated alcohol and deaerated deionized water. Control samples were exposed to uninoculated medium and as-polished coupons provided baseline for comparison. The following sulfides were formed during the exposure: FeS, FeS{sub 2}, MoS{sub 2}, Cr{sub 2}S{sub 3}, NiS, and possibly Fe{sub 1{minus}x}S. These sulfides were mainly in the outer layers of the surface so that the passive film was not markedly deteriorated. In addition, a Mo(V) species was formed in the biofilm and increased the passivity by: (1) reducing the bacterial activity and sulfate reduction through formation of molybdate and (2) forming a Mo(v) species which is insoluble in 0.1 M HCl.

  18. Phospholipid Evidence for Methanogenic Archaea and Sulfate-reducing Bacteria in Coalbed Methane Wells in the Powder River Basin, Wyoming

    NASA Astrophysics Data System (ADS)

    Glossner, A.; Flores, R. M.; Mandernack, K.

    2008-12-01

    The Powder River Basin (PRB) comprises roughly 22,000 mi2 in northeastern Wyoming and southeastern Montana; it is a major source of coal and natural gas in the Rocky Mountain and Great Plains regions. The coalbed methane (CBM) produced from Paleocene Fort Union Formation coals in the PRB is thought primarily to be of bacterial origin due to its low ?13C values of -51 to -82 permil. Determination of the timing of methanogenesis, however, requires a methodology suitable for distinguishing viable methanogenic microorganisms. Here we provide evidence of living methanogenic Archaea and sulfate- reducing bacteria collected from co-produced water from CBM wells using phospholipid fatty acid (PLFA) and phospholipid ether lipid (PLEL) analyses. Twelve producing wells were sampled in May, 2007, using a high- pressure filtering apparatus. PLFAs were analyzed as fatty acid methyl esters and PLELs analyzed by their liberated core components using gas chromatography/mass spectrometry. Phospholipid analyses revealed an ecosystem dominated by Archaea, as the Archaeal isoprenoid, phytane, was the dominant phospholipid observed in nine of the wells sampled. Total microbial biomass estimates ranged from 1.1 ×106 cells/L to 8.3 ×107 cells/L, with the proportion of Archaeal cells ranging from 77.5 to 99.7 percent. In addition, the biomarkers 10me16:0, and cy17:0, considered to be biomarkers for genera of sulfate-reducing bacteria, were observed in several wells. The dominance of lipids from living Archaea in co- produced waters from CBM wells provides evidence supporting a recent origin of gas in the PRB coals.

  19. 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 ?-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

  20. 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).

  1. 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 ...

  2. Isolation of sulfate?reducing bacteria from deep sediment layers of the pacific ocean

    Microsoft Academic Search

    Stephen P. Barnes; Samuel D. Bradbrook; Barry A. Cragg; Julian R. Marchesi; Andrew J. Weightman; John C. Fry; R. John Parkes

    1998-01-01

    Bacterial populations exist at great depths in marine sediments, but little is known about the type and characteristics of organisms in this unique bacterial environment. Cascadia Margin sediments from the Pacific Ocean have deep bacterial activity and bacterial populations, which are stimulated around a gas hydrate zone (215–225 m below sea floor [mbsf]). Bacterial sulfate reduction is the dominant anaerobic

  3. Simultaneous determination of mercury methylation and demethylation capacities of various sulfate-reducing bacteria using species-specific isotopic tracers.

    PubMed

    Bridou, Romain; Monperrus, Mathilde; Gonzalez, Pablo Rodriguez; Guyoneaud, Rémy; Amouroux, David

    2011-02-01

    The use of species-specific isotopic tracers for inorganic and methyl mercury has allowed the simultaneous determination of the methylation and demethylation potentials of pure culture of isolated sulfate-reducing (SR) bacterial strains using low Hg species concentration levels (7 µg/L (199)Hg(II), 1 µg/L Me(201)Hg). A major advantage of the method reported here is that it can be used to follow simultaneously both the degradation of the species added but also the formation of their degradation products and thus the determination during the same incubation of the specific methylation/demethylation yields and rate constants. Methylation/demethylation capacities and extents have been found to differ between the tested strains and the tested conditions. The methylating/demethylating capacities of bacteria appear to be strain specific. All the methylating strains were found to demethylate methylmercury (MeHg). The active mechanism responsible for Hg methylation appears directly dependent on the bacterial activity but is not dependent on the metabolism used by the tested bacteria (sulfate reduction, fermentation, or nitrate respiration). The results provide confirmation that SR strains contribute to MeHg demethylation under anoxic conditions, leading to Hg(II) as the end product, consistent with the oxidative degradation pathway. Kinetic experiments have allowed specific transformation rate constants to be addressed for the two reversible processes and the reactivity of each isotopic tracer to be compared. The differential reactivity highlighted the different steps involved in the two apparent processes (i.e., uptake plus internal transformation of mercury species). Methylation appears as the slowest process, mainly controlled by the assimilation of Hg(II), whereas demethylation is faster and not dependent on the MeHg concentration. PMID:21038431

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

    SciTech Connect

    Canty, M. [MSE Inc., Butte, MT (United States)

    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.

  5. Hydrogen embrittlement of cathodically protected high-strength, low-alloy steels exposed to sulfate-reducing bacteria

    SciTech Connect

    Robinson, M.J.; Kilgallon, P.J. (Cranfield Univ. (United Kingdom). School of Industrial and Manufacturing Science)

    1994-08-01

    Hydrogen embrittlement (HE) of two high-strength, low-alloy steels was studied in conditions typical of the marine environment. Double-cantilever beam specimens, heat-treated to produce the microstructure in the heat-affected zone of a weld, were tested in seawater containing sulfate-reducing bacteria (SRB) at a range of cathodic protection potentials. The threshold stress intensities (K[sub th]) required to cause subcritical crack propagation were recorded. The concentration of H absorbed by the steel (C[sub 0]) was measured using a permeation technique and was shown to be higher at more cathodic potentials and significantly increased when SRB were present. An inverse relationship was established between log K[sub th] and C[sub 0] for sterile and biologically active environments. It was concluded that crack propagation occurred by a single HE mechanism, regardless of whether SRB were present. The bacteria were believed to increase sulfide concentration in the biofilm at the metal surface, which promoted increased C[sub 0].

  6. Growth and Population Dynamics of Anaerobic Methane-Oxidizing Archaea and Sulfate-Reducing Bacteria in a Continuous-Flow Bioreactor

    Microsoft Academic Search

    Peter R. Girguis; Aaron E. Cozen; Edward F. DeLong

    2005-01-01

    The consumption of methane in anoxic marine sediments is a biogeochemical phenomenon mediated by two archaeal groups (ANME-1 and ANME-2) that exist syntrophically with sulfate-reducing bacteria. These anaerobic methanotrophs have yet to be recovered in pure culture, and key aspects of their ecology and physiology remain poorly understood. To characterize the growth and physiology of these anaerobic meth- anotrophs and

  7. 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...

  8. 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...

  9. Sulfate-Reducing Bacteria in Floating Macrophyte Rhizospheres from an Amazonian Floodplain Lake in Bolivia and Their Association with Hg Methylation

    Microsoft Academic Search

    Darõ ´ o Acha ´; Volga Iniguez; Marc Roulet; J. R. D. Guimaraes; R. Luna; L. Alanoca; S. Sanchez

    2005-01-01

    Five subgroups of sulfate-reducing bacteria (SRB) were detected by PCR in three macrophyte rhizospheres (Polygonum densiflorum, Hymenachne donacifolia, and Ludwigia helminthorriza) and three subgroups in Eich- hornia crassipes from La Granja, a floodplain lake from the upper Madeira basin. The SRB community varied according to the macrophyte species but with different degrees of association with their roots. The rhizosphere of

  10. 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

  11. Molecular Ecological Analysis of the Succession and Diversity of Sulfate-Reducing Bacteria in the Mouse Gastrointestinal Tract

    PubMed Central

    Deplancke, B.; Hristova, K. R.; Oakley, H. A.; McCracken, V. J.; Aminov, R.; Mackie, R. I.; Gaskins, H. R.

    2000-01-01

    Intestinal sulfate-reducing bacteria (SRB) growth and resultant hydrogen sulfide production may damage the gastrointestinal epithelium and thereby contribute to chronic intestinal disorders. However, the ecology and phylogenetic diversity of intestinal dissimilatory SRB populations are poorly understood, and endogenous or exogenous sources of available sulfate are not well defined. The succession of intestinal SRB was therefore compared in inbred C57BL/6J mice using a PCR-based metabolic molecular ecology (MME) approach that targets a conserved region of subunit A of the adenosine-5?-phosphosulfate (APS) reductase gene. The APS reductase-based MME strategy revealed intestinal SRB in the stomach and small intestine of 1-, 4-, and 7-day-old mice and throughout the gastrointestinal tract of 14-, 21-, 30-, 60-, and 90-day-old mice. Phylogenetic analysis of APS reductase amplicons obtained from the stomach, middle small intestine, and cecum of neonatal mice revealed that Desulfotomaculum spp. may be a predominant SRB group in the neonatal mouse intestine. Dot blot hybridizations with SRB-specific 16S ribosomal DNA (rDNA) probes demonstrated SRB colonization of the cecum and colon pre- and postweaning and colonization of the stomach and small intestine of mature mice only. The 16S rDNA hybridization data further demonstrated that SRB populations were most numerous in intestinal regions harboring sulfomucin-containing goblet cells, regardless of age. Reverse transcriptase PCR analysis demonstrated APS reductase mRNA expression in all intestinal segments of 30-day-old mice, including the stomach. These results demonstrate for the first time widespread colonization of the mouse intestine by dissimilatory SRB and evidence of spatial-specific SRB populations and sulfomucin patterns along the gastrointestinal tract. PMID:10788396

  12. 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

  13. 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

  14. 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. [State Univ. of New York, Stony Brook, NY (United States). Dept. of Materials Science and Engineering; Gillow, J.B.; Francis, A.J. [Brookhaven National Lab., Upton, NY (United States). Dept. of Applied Science

    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.

  15. Bacterial community structure and activity of sulfate reducing bacteria in a membrane aerated biofilm analyzed by microsensor and molecular techniques.

    PubMed

    Liu, Hong; Tan, Shuying; Sheng, Zhiya; Liu, Yang; Yu, Tong

    2014-11-01

    The activities and vertical spatial distribution of sulfate reducing bacteria (SRB) in an oxygen (O2 )-based membrane aerated biofilm (MAB) were investigated using microsensor (O2 and H2 S) measurements and molecular techniques (polymerase chain reaction-denaturing gradient gel electrophoresis [PCR-DGGE] and fluorescence in situ hybridization [FISH]). The O2 concentration profile revealed that O2 penetrated from the bottom (substratum) of the gas permeable membrane, and was gradually consumed within the biofilm until it was completely depleted near the biofilm/bulk liquid interface, indicating oxic and anoxic zone in the MAB. The H2 S concentration profile showed that H2 S production was found in the upper 285?µm of the biofilm, indicating a high activity of SRB in this region. The results from DGGE of the PCR-amplified dissimilatory sulfite reductase subunit B (dsrB) gene and FISH showed an uneven spatial distribution of SRB. The maximum SRB biomass was located in the upper biofilm. The information from the molecular analysis can be supplemented with that from microsensor measurements to better understand the microbial community and activity of SRB in the MAB. PMID:24890472

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

    Microsoft Academic Search

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

    2006-01-01

    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

  17. Ecology of Sulfate-Reducing Bacteria in an Iron-Dominated, Mining-Impacted Freshwater Sediment

    Microsoft Academic Search

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

    2009-01-01

    A legacy of lead and silver mining in its headwaters left Lake Coeur d'Alene, Idaho with a sediment body that is highly reduced and contains up to 100 g kg ?1 iron and a smaller fraction of chemically active sulfi de phases. Th e dynamic character of these sulfi des and their importance for the sequestering of contaminating trace elements

  18. 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 ?-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 ?g/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

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

    SciTech Connect

    Cardenas, Erick [Michigan State University, East Lansing; Wu, Wei-min [Stanford University; Leigh, Mary Beth [Michigan State University, East Lansing; Carley, Jack M [ORNL; Carroll, Sue L [ORNL; Gentry, Terry [Texas A& M University; Luo, Jian [Georgia Institute of Technology; Watson, David B [ORNL; Gu, Baohua [ORNL; Ginder-Vogel, Matthew A. [Stanford University; Kitanidis, Peter K. [Stanford University; Jardine, Philip [University of Tennessee; Kelly, Shelly D [Argonne National Laboratory (ANL); Zhou, Jizhong [University of Oklahoma, Norman; Criddle, Craig [Stanford University; Marsh, Terence [Michigan State University, East Lansing; Tiedje, James [Michigan State University, East Lansing

    2010-08-01

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

  20. 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 [Michigan State University, East Lansing; Leigh, Mary Beth [Michigan State University, East Lansing; Marsh, Terence [Michigan State University, East Lansing; Tiedje, James M. [Michigan State University, East Lansing; Wu, Wei-min [Stanford University; Luo, Jian [Stanford University; Ginder-Vogel, Matthew [Stanford University; Kitanidis, Peter K. [Stanford University; Criddle, Craig [Stanford University; Carley, Jack M [ORNL; Carroll, Sue L [ORNL; Gentry, Terry J [ORNL; Watson, David B [ORNL; Gu, Baohua [ORNL; Jardine, Philip M [ORNL; Zhou, Jizhong [ORNL

    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.

  1. 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

  2. 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

  3. 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).

  4. Modeling the activity of sulfate-reducing bacteria and the effects of container corrosion in an underground nuclear waste disposal vault

    SciTech Connect

    King, F.; Kolar, M.; Stroes-Gascoyne, S.; Bellingham, P.; Chu, J.; Dawe, P.V.

    1999-07-01

    A mathematical model has been developed to predict the extent of sulfate reduction by sulfate-reducing bacteria (SRB) in an underground nuclear waste disposal vault and the consequences for corrosion of the waste package. The model is based on a series of mass-balance equations that describe the kinetics of sulfate reduction by two types of SRB (one organotrophic and one chemoheterotrophic), the growth and death of SRB, the supply and consumption of nutrients (acetate and hydrogen) and reactants (SO{sub 4}{sup 2{minus}}) and the consumption of sulfide by precipitation with aqueous Fe(II) or by container corrosion. The disposal vault is described by a series of 1-D mass-transport barriers representing the buffer and backfill materials and fractured rock. The model can also be used to simulate the effects of {gamma}-radiation and desiccation of the buffer and backfill materials on the extent of microbial activity.

  5. Enrichment of sulfate-reducing bacteria and resulting mineral formation in media mimicking pore water metal ion concentrations and pH conditions of acidic pit lakes.

    PubMed

    Meier, Jutta; Piva, Angela; Fortin, Danielle

    2012-01-01

    Acid mine drainage sites are extreme environments with high acidity and metal ion concentrations. Under anoxic conditions, microbial sulfate reduction may trigger the formation of secondary minerals as a result of H2S production and pH increase. This process was studied in batch experiments with enrichment cultures from acidic sediments of a pit lake using growth media set at different pH values and containing elevated concentrations of Fe²? and Al³?. At initial pH values of 5 and 6, sulfate reduction occurred shortly after inoculation. Sulfate- reducing bacteria affiliated to the genus Desulfosporosinus predominated the microbial communities as shown by 16S rRNA gene analysis performed at the end of the incubation. At initial pH values of 3 and 4, sulfate reduction and cell growth occurred only after an extended lag phase, however, at a higher rate than in the less acidic assays. At the end of the growth phase, enrichments were dominated by Thermodesulfobium spp. suggesting that these sulfate reducers were better adapted to acidic conditions. Iron sulfides in the bulk phase were common in all assays, but specific aluminum precipitates formed in close association with cell surfaces and may function as a detoxification mechanism of dissolved Al species at low pH. PMID:22066948

  6. Degradative capacities and 16S rRNA-targeted whole-cell hybridization of sulfate-reducing bacteria in an anaerobic enrichment culture utilizing alkylbenzenes from crude oil.

    PubMed Central

    Rabus, R; Fukui, M; Wilkes, H; Widdle, F

    1996-01-01

    A mesophilic sulfate-reducing enrichment culture growing anaerobically on crude oil was used as a model system to study which nutritional types of sulfate-reducing bacteria may develop on original petroleum constituents in oil wells, tanks, and pipelines. Chemical analysis of oil hydrocarbons during growth revealed depletion of toluene and o-xylene within 1 month and of m-xylene, o-ethyltoluene, m-ethyltoluene, m-propyltoluene, and m-isopropyltoluene within approximately 2 months. In anaerobic counting series, the highest numbers of CFU (6 x 10(6) to 8 x 10(6) CFU ml-1) were obtained with toluene and benzoate. Almost the same numbers were obtained with lactate, a substrate often used for detection of the vibrio-shaped, incompletely oxidizing Desulfovibrio sp. In the present study, however, lactate yielded mostly colonies of oval to rod-shaped, completely oxidizing, sulfate-reducing bacteria which were able to grow slowly on toluene or crude oil. Desulfovibrio species were detected only at low numbers (3 x 10(5) CFU ml-1). In agreement with this finding, a fluorescently labeled, 16S rRNA-targeted oligonucleotide probe described in the literature as specific for members of the Desulfovibrionaceae (suggested family) hybridized only with a small portion (< 5%) of the cells in the enrichment culture. These results are consistent with the observation that known Desulfovibrio species do not utilize aromatic hydrocarbons, the predominant substrates in the enrichment culture. All known sulfate-reducing bacteria which utilize aromatic compounds belong to a separate branch, the Desulfobacteriaceae (suggested family). Most members of this family are complete oxidizers. For specific hybridization with members of this branch, the probe had to be modified by a nucleotide exchange. Indeed, this modified probe hybridized with more than 95% of the cells in the enrichment culture. The results show that completely oxidizing, alkylbenzene-utilizing sulfate-reducing bacteria rather than Desulfovibrio species have to be considered in attempts to understand the microbiology of sulfide production in oil wells, tanks, and pipelines when no electron donors other than the indigenous oil constituents are available. PMID:8837415

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

    PubMed Central

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

    1991-01-01

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

  8. 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 × 10? 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

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

    PubMed Central

    Nanninga, Henk J.; Gottschal, Jan C.

    1987-01-01

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

  10. Volatile Fatty Acids andHydrogen asSubstrates forSulfate- Reducing Bacteria inAnaerobic Marine Sediment

    Microsoft Academic Search

    JAN S; DORTE CHRISTENSEN

    1981-01-01

    Theaddition of20mM MoO2-(molybdate) toareduced marinesediment completely inhibited theSO-reduction activity byabout50nmolg-1h-'(wet sediment). Acetate accumulated ataconstant rateofabout25nmolg-1h-1 immediately afterMoO4- addition andgaveameasure ofthepreceding utilization rate ofacetate bytheSO4--reducing bacteria. Similarly, propionate andbutyrate (including isobutyrate) accumulated atconstant rates of3to7and2to4nmol g'h-1, respectively. TherateofH2accumulation wasvariable, andarange of0 to16nmolg-1h-'wasrecorded. Animmediate increase ofthemethanogenic activity by2to3nmolg-1h-1 wasapparently duetoarelease ofthecompetition forH2bytheabsence ofSO4-reduction. Ifpropionate andbutyrate were completely oxidized bytheSO4-reducing bacteria, thestoichiometry ofthe

  11. 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 ? (aprA) and methyl coenzyme M reductase ? (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 ?-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

  12. 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.

  13. Sulfate Reduction Dynamics and Enumeration of Sulfate-Reducing Bacteria in Hypersaline Sediments of the Great Salt Lake (Utah,USA)

    Microsoft Academic Search

    K. K. Brandt; F. Vester; A. N. Jensen; K. Ingvorsen

    2001-01-01

      Bacterial sulfate reduction activity (SRA) was measured in surface sediments and slurries from three sites in the Great Salt\\u000a Lake (Utah, USA) using radiolabeled 35S-sulfate. High rates of sulfate reduction (363 ± 103 and 6,131 ± 835 nmol cm-3 d-1)\\u000a were measured at two sites in the moderately hypersaline southern arm of the lake, whereas significantly lower rates (32 ±

  14. A biological process for the reclamation of flue gas desulfurization gypsum using mixed sulfate-reducing bacteria with inexpensive carbon sources.

    PubMed

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

    1997-01-01

    A combined chemical and biological process for the recycling of flue gas desulfurization (FGD) gypsum into calcium carbonate and elemental sulfur is demonstrated. In this process, a mixed culture of sulfate-reducing bacteria (SRB) utilizes inexpensive carbon sources, such as sewage digest or synthesis gas, to reduce FGD gypsum to hydrogen sulfide. The sulfide is then oxidized to elemental sulfur via reaction with ferric sulfate, and accumulating calcium ions are precipitated as calcium carbonate using carbon dioxide. Employing anaerobically digested municipal sewage sludge (AD-MSS) medium as a carbon source, SRBs in serum bottles demonstrated an FGD gypsum reduction rate of 8 mg/L/h (10(9) cells)(-1). A chemostat with continuous addition of both AD-MSS media and gypsum exhibited sulfate reduction rates as high as 1.3 kg FGD gypsum/m(3)d. The increased biocatalyst density afforded by cell immobilization in a columnar reactor allowed a productivity of 152 mg SO(4) (-2)/Lh or 6.6 kg FGD gypsum/m(3)d. Both reactors demonstrated 100% conversion of sulfate, with 75-100% recovery of elemental sulfur and chemical oxygen demand utilization as high as 70%. Calcium carbonate was recovered from the reactor effluent on precipitation using carbon dioxide. It was demonstrated that SRBs may also use synthesis gas (CO, H(2), and CO(2) in the reduction of gypsum, further decreasing process costs. The formation of two marketable products-elemental sulfur and calcium carbonate-from FGD gypsum sludge, combined with the use of a low-cost carbon source and further improvements in reactor design, promises to offer an attractive alternative to the landfilling of FGD gypsum. PMID:18576124

  15. Distribution of sulfate-reducing bacteria, O2, and H2S in photosynthetic biofilms determined by oligonucleotide probes and microelectrodes.

    PubMed Central

    Ramsing, N B; Kühl, M; Jørgensen, B B

    1993-01-01

    The vertical distribution of sulfate-reducing bacteria (SRB) in photosynthetic biofilms from the trickling filter of a sewage treatment plant was investigated with oligonucleotide probes binding to 16S rRNA. To demonstrate the effect of daylight and photosynthesis and thereby of increased oxygen penetration, we incubated two 4-mm-thick biofilm samples in darkness or exposed to light at natural intensity. Gradients of O2, H2S, and pH were examined with microelectrodes during incubation. The samples were subsequently frozen with liquid nitrogen and sliced on a cryomicrotome in 20-microns vertical slices. Fluorescent-dye-conjugated oligonucleotides were used as "phylogenetic" probes to identify single cells in the slices. Oligonucleotide sequences were selected which were complementary to short sequence elements (16 to 20 nucleotides) within the 16S rRNA of sulfate-reducing bacteria. The probes were labeled with fluorescein or rhodamine derivatives for subsequent visualization by epifluorescence microscopy. Five probes were synthesized for eukaryotes, eubacteria, SRB (including most species of the delta group of purple bacteria), Desulfobacter spp., and a nonhybridizing control. The SRB were unevenly distributed in the biofilm, being present in all states from single scattered cells to dense clusters of several thousand cells. To quantify the vertical distribution of SRB, we counted cells along vertical transects through the biofilm. This was done in a blind experiment to ascertain the reliability of the staining. A negative correlation between the vertical distribution of positively stained SRB cells and the measured O2 profiles was found. The distribution differed in light- and dark-incubated samples presumably because of the different extensions of the oxic surface layer. In both cases the SRB were largely restricted to anoxic layers. Images PMID:7506896

  16. Sulfate-Reducing Bacteria in Floating Macrophyte Rhizospheres from an Amazonian Floodplain Lake in Bolivia and Their Association with Hg Methylation

    PubMed Central

    Achá, Darío; Iñiguez, Volga; Roulet, Marc; Guimarães, Jean Remy Davée; Luna, Ruddy; Alanoca, Lucia; Sanchez, Samanta

    2005-01-01

    Five subgroups of sulfate-reducing bacteria (SRB) were detected by PCR in three macrophyte rhizospheres (Polygonum densiflorum, Hymenachne donacifolia, and Ludwigia helminthorriza) and three subgroups in Eichhornia crassipes from La Granja, a floodplain lake from the upper Madeira basin. The SRB community varied according to the macrophyte species but with different degrees of association with their roots. The rhizosphere of the C4 plant Polygonum densiflorum had higher frequencies of SRB subgroups as well as higher mercury methylation potentials (27.5 to 36.1%) and carbon (16.06 ± 5.40%), nitrogen (2.03 ± 0.64%), Hg (94.50 ± 6.86 ng Hg g?1), and methylmercury (8.25 ± 1.45 ng Hg g?1) contents than the rhizosphere of the C3 plant Eichhornia crassipes. Mercury methylation in Polygonum densiflorum and Eichhornia crassipes was reduced when SRB metabolism was inhibited by sodium molybdate. PMID:16269796

  17. 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

  18. Purification and characterization of a monomeric isocitrate dehydrogenase from the sulfate-reducing bacterium Desulfobacter vibrioformis and demonstration of the presence of a monomeric enzyme in other bacteria.

    PubMed

    Steen, I H; Madsen, M S; Birkeland, N K; Lien, T

    1998-03-01

    NADP(+)-specific isocitrate dehydrogenase (EC 1.1.1.42) was purified to homogeneity from the sulfate-reducing bacterium Desulfobacter vibrioformis, and shown to be a monomeric protein with a molecular mass of 80 kDa. The pH and temperature optima were 8.5 and 45 degrees C, respectively. The N-terminal amino acid sequence (Thr, Glu, Thr, Ile, Arg, Trp, Thr, X, Thr, Asp, Glu, Ala, Pro, Leu, Leu, Ala, Thr) showed similarity with that of other known monomeric isocitrate dehydrogenases. Catalytically active isocitrate dehydrogenase from D. vibrioformis was obtained by activity staining after SDS-PAGE and removal of SDS from the gel. This technique revealed a NADP(+)-dependent monomeric enzyme in other Desulfobacter spp., Desulfuromonas acetoxidans and Chlorobium tepidium. These findings imply that monomeric isocitrate dehydrogenases are present in distantly related bacteria and indicate an early evolution of monomeric isocitrate dehydrogenases in the bacterial lineage. PMID:9495015

  19. Unexpected population distribution in a microbial mat community: Sulfate-reducing bacteria localized to the highly oxic chemocline in contrast to a eukaryotic preference for anoxia

    SciTech Connect

    Minz, D.; Fishbain, S.; Green, S.J.; Muyzer, G.; Cohen, Y.; Rittmann, B.E.; Stahl, D.A.

    1999-10-01

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

  20. 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

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

    PubMed

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

    2012-02-01

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

  2. Co-existence of physiologically similar sulfate-reducing bacteria in a full-scale sulfidogenic bioreactor fed with a single organic electron donor

    PubMed Central

    Dar, Shabir A.; Stams, Alfons J. M.; Kuenen, J. Gijs

    2007-01-01

    A combination of culture-dependent and independent methods was used to study the co-existence of different sulfate-reducing bacteria (SRB) in an upflow anaerobic sludge bed reactor treating sulfate-rich wastewater. The wastewater was fed with ethanol as an external electron donor. Twenty six strains of SRB were randomly picked and isolated from the highest serial dilution that showed growth (i.e. 108). Repetitive enterobacterial palindromic polymerase chain reaction and whole cell protein profiling revealed a low genetic diversity, with only two genotypes among the 26 strains obtained in the pure culture. The low genetic diversity suggests the absence of micro-niches within the reactor, which might be due to a low spatial and temporal micro-heterogeneity. The total 16S rDNA sequencing of two representative strains L3 and L7 indicated a close relatedness to the genus Desulfovibrio. The two strains differed in as many as five physiological traits, which might allow them to occupy distinct niches and thus co-exist within the same habitat. Whole cell hybridisation with fluorescently labeled oligonucleotide probes was performed to characterise the SRB community in the reactor. The isolated strains Desulfovibrio L3 and Desulfovibrio L7 were the most dominant SRB, representing 30–35% and 25–35%, respectively, of the total SRB community. Desulfobulbus-like bacteria contributed for 20–25%, and the Desulfobacca acetoxidans-specific probe targeted approximately 15–20% of the total SRB. The whole cell hybridisation results thus revealed a consortium of four different species of SRB that can be enriched and maintained on a single energy source in a full-scale sulfidogenic reactor. PMID:17440719

  3. Interactions between methanogenic and nitrate reducing bacteria during the anaerobic digestion of an industrial sulfate rich wastewater

    Microsoft Academic Search

    Gilles Percheron; Nicolas Bernet; René Moletta

    1999-01-01

    The effect of nitrate addition on the anaerobic digestion of an industrial sulfate rich wastewater was investigated using batch cultures. A high chemical oxygen demand\\/NO3-N ratio did not favor the dissimilatory nitrate reduction to ammonia. Denitrification was the main nitrate reduction pathway at all chemical oxygen demand\\/NO3-N ratios tested. A lag phase, presumably caused by a high initial sulfide content,

  4. 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

  5. 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

  6. 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 PF2803(T) 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 PF2803(T). 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

  7. 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.

  8. Degradative capacities and 16S rRNA-targeted whole-cell hybridization of sulfate-reducing bacteria in an anaerobic enrichment culture utilizing alkylbenzenes from crude oil

    Microsoft Academic Search

    RALF RABUS; F. Widdel; Manabu Fukui

    1996-01-01

    Production of sulfide in oil field waters, a process which is referred to as souring, has been of concern. Hydrogen sulfide may lead to poisoning, contamination of oil and gas, corrosion of pipelines, conversion of iron mineral to ferrous sulfide. This study used a previously established sulfate-reducing enrichment culture on crude oil as a model system of bacterial habitats in

  9. Test-kits for thiosulfate-reducing bacteria

    SciTech Connect

    Crolet, J.L. [Elf Aquitaine Production, Pau (France); Magot, M. [Elf Aquitaine Group, Labege (France); Brazy, J.L. [Elf Congo, Pointe Noire (Congo)

    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. Competition and Coexistence of Sulfate-Reducing and Methanogenic Populations in Anaerobic Biofilms

    PubMed Central

    Raskin, L.; Rittmann, B. E.; Stahl, D. A.

    1996-01-01

    The microbial population structure and function of natural anaerobic communities maintained in laboratory fixed-bed biofilm reactors were tracked before and after a major perturbation, which involved the addition of sulfate to the influent of a reactor that had previously been fed only glucose (methanogenic), while sulfate was withheld from a reactor that had been fed both glucose and sulfate (sulfidogenic). The population structure, determined by using phylogenetically based oligonucleotide probes for methanogens and sulfate-reducing bacteria, was linked to the functional performance of the biofilm reactors. Before the perturbation, the methanogenic reactor contained up to 25% methanogens as well as 15% sulfate-reducing bacteria, even though sulfate was not present in the influent of this reactor. Methanobacteriales and Desulfovibrio spp. were the most abundant methanogens and sulfate-reducing bacteria, respectively. The presence of sulfate-reducing bacteria (primarily Desulfovibrio spp. and Desulfobacterium spp.) in the absence of sulfate may be explained by their ability to function as proton-reducing acetogens and/or fermenters. Sulfate reduction began immediately following the addition of sulfate consistent with the presence of significant levels of sulfate-reducing bacteria in the methanogenic reactor, and levels of sulfate-reducing bacteria increased to a new steady-state level of 30 to 40%; coincidentally, effluent acetate concentrations decreased. Notably, some sulfate-reducing bacteria (Desulfococcus/Desulfosarcina/Desulfobotulus group) were more competitive without sulfate. Methane production decreased immediately following the addition of sulfate; this was later followed by a decrease in the relative concentration of methanogens, which reached a new steady-state level of approximately 8%. The changeover to sulfate-free medium in the sulfidogenic reactor did not cause a rapid shift to methanogenesis. Methane production and a substantial increase in the levels of methanogens were observed only after approximately 50 days following the perturbation. PMID:16535428

  11. Acetate production from oil under sulfate-reducing conditions in bioreactors injected with sulfate and nitrate.

    PubMed

    Callbeck, Cameron M; Agrawal, Akhil; Voordouw, Gerrit

    2013-08-01

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

  12. Effect of COD\\/Sulfate Ratios on Batch Anaerobic Digestion Using Sulfate-Reduction Bacteria

    Microsoft Academic Search

    Heng-heng Cao; Hong-guo Zhang; Ding-gui Luo; Yong-heng Chen

    2011-01-01

    A study on effects of the COD\\/sulfate ratio on characteristics of sulfate-reduction bacteria (SRB) in activated sludge of a UASB reactor was performed in batch anaerobic digestion experiment. Changes of pH in samples were 7.22~8.17 which was beneficial to the growth of SRB with high sulfate removal efficiency. Sulfate reduction efficiencies of COD\\/sulfate ratios from 0.43 to 3.03 were 18.7(R1),

  13. DIVERSITY OF SULFATE?REDUCING GENES (dsrAB) IN SEDIMENTS FROM PUGET SOUND

    Microsoft Academic Search

    S. M. Tiquia

    2008-01-01

    The aims of this study were to characterize the population structure and diversity of sulfate?reducing bacteria (SRB) from three distinct sites at Puget Sound, and relate the biogeochemical properties of the sediments to the sulfate?reducer communities. The population composition and diversity of sulfate?reducing bacteria carrying dsrAB genes from surface Puget Sound sediments was investigated using a polymerase chain reaction?based cloning

  14. ORIGINAL ARTICLE Impact of elevated nitrate on sulfate-reducing

    E-print Network

    Hazen, Terry

    -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-sensitive metals has been proposed as a promising strategy to remediate metal-contaminated

  15. 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

  16. 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

  17. Importance of Sulfate-Reducing Bacterial Activity in Controlling Mercury Methylation in Anoxic Estuarine Sediment Slurries

    Microsoft Academic Search

    S. Han; A. Obraztsova; P. Pretto; D. D. Deheyn; J. Gieskes; B. M. Tebo

    2007-01-01

    Solution speciation of dissolved Hg has been considered an important factor controlling Hg methylation in anoxic sediments. Our previous research with sediments from the Venice Lagoon, Italy, however, has shown that the Hg methylation rate is affected by the activity of sulfate-reducing bacteria, which varies widely within the lagoon. To understand the role of sulfate-reducing bacterial activity in monomethylmercury (MMHg)

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

    EPA Science Inventory

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

  19. The sulphate-reducing bacteria

    Microsoft Academic Search

    1984-01-01

    This monograph surveys knowledge about an unusual and little-studied group of microbes, bringing together information that has hitherto been widely scattered throughout the scientific literature. The sulphate-reducing bacteria cannot grow in air; they respire sulphates instead of oxygen and are difficult to isolate and study. Nevertheless, much progress has been made in recent years and has revealed novelties of biochemistry

  20. 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.

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

    Microsoft Academic Search

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

    2005-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

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

  3. 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.

  4. Influence of sulfate reducing bacterial biofilm on corrosion behavior of low-alloy, high-strength steel (API-5L X80)

    E-print Network

    Influence of sulfate reducing bacterial biofilm on corrosion behavior of low-alloy, high Microbiologically influenced corrosion (MIC) Sulfate-reducing bacteria (SRB) Biofilm and iron sulfide a b s t r a c reducing bacteria (SRB). The biofilm and pit morphology that developed with time were char- acterized

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

    SciTech Connect

    Santegoeds, C.M.; Ferdelman, T.G.; Muyzer, G.; Beer, D. de [Max Planck Inst. for Marine Microbiology, Bremen (Germany)

    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.

  6. 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.

  7. Evaluation of the Sulfate-Reducing Bacterial Population Associated With Stored Swine Slurry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sulfate reducing bacteria (SRB) in swine manure storage pit (SMSP) slurries are responsible for the production of hydrogen sulfide emitted from livestock facilities. However, little is known about the prevalence and diversity of SRB in livestock wastes. In this study, SRB populations in SMSP slurrie...

  8. Anaerobic biotransformation of fuel oxygenates under sulfate-reducing conditions

    Microsoft Academic Search

    Piyapawn Somsamak; Robert M Cowan; Max M Häggblom

    2001-01-01

    The anaerobic biotransformation of methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and methyl tert-amyl ether (TAME) was evaluated under different anoxic electron-accepting conditions. Enrichments were established with a polluted estuarine sediment inoculum under conditions promoting denitrification, sulfate reduction, Fe(III) reduction, or methanogenesis. Complete loss of MTBE and TAME was observed under sulfate-reducing conditions, concomitant with the reduction of sulfate.

  9. Vertical distribution of sulfate reduction, methane production, and bacteria in marine sediments

    Microsoft Academic Search

    Michael R. Winfrey; Danielle G. Marty; Armand J. M. Bianchi; David M. Ward

    1981-01-01

    The vertical distribution of porewater chemistry, and the numbers and activities of methane?producing bacteria (MPB) and sulfate?re?ducing bacteria (SRB) were examined in shallow subtidal marine sediment cores. Sulfate concentrations decreased sharply below 5 cm in three of the four cores collected, and methane levels were highest (2500 to 3500 nmol\\/ml) immediately below the depth where sulfate was depleted. The fourth

  10. 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

  11. 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

  12. Influence of Sulfate on the Transport of Bacteria in Quartz Sand

    NASA Astrophysics Data System (ADS)

    Shen, Xiufang; Han, Peng; Yang, Haiyan; Kim, Hyunjung; Tong, Meiping

    2013-04-01

    The influence of sulfate on the transport of bacteria in packed quartz sand was examined at a constant 25 mM ionic strength with the sulfate concentration progressively increased from 0 to 20 mM at pH 6.0. Two representative cell types, Escherichia coli BL21 (Gram-negative) and Bacillus subtilis (Gram-positive), were used to determine the effect of sulfate on cell transport behavior. For both examined cell types, the breakthrough plateaus in the presence of sulfate in suspensions were higher and the corresponding retained profiles were lower than those without sulfate ions, indicating that the presence of sulfate in suspensions increased cell transport in packed quartz sand regardless of the examined cell types (Gram-positive or Gram-negative). Moreover, the enhancement of bacteria transport induced by the presence of sulfate was more pronounced with increasing sulfate concentration from 5 to 20 mM. In contrast with the results for EPS-present bacteria, the presence of sulfate in solutions did not change the transport behavior for EPS-removed cells. The zeta potentials of EPS-present cells with sulfate were found to be more negative relative to those without sulfate in suspensions, whereas, the zeta potentials for EPS-removed cells in the presence of sulfate were similar as those without sulfate. We proposed that sulfate could interact with EPS on cell surfaces and thus negatively increased the zeta potentials of bacteria, contributing to the increased transport in the presence of sulfate in suspensions.

  13. Inhibition of sulfate-reducing and methanogenic activities of anaerobic sewer biofilms by ferric iron dosing.

    PubMed

    Zhang, Lishan; Keller, Jürg; Yuan, Zhiguo

    2009-09-01

    Ferric iron is commonly used for sulfide precipitation in sewers, thus achieving corrosion and odour control. Its impact on the activities of sulfate-reducing bacteria and methanogens in anaerobic sewer biofilms is investigated in this study. Two lab-scale rising main sewer systems fed with real sewage were operated for 8 months. One received Fe(3+) dosage (experimental system) and the other was used as a control. In addition to precipitating sulfide from bulk water, Fe(3+) dosage was found to significantly inhibit sulfate reduction and methane production by sewer biofilms. The experimental reactor discharged an effluent containing a higher concentration of sulfate and a lower concentration of methane in comparison with the reference reactor. Batch experiments showed that the addition of ferric ions reduced the sulfate reduction and methane production rates of the sewer biofilms by 60% and 80%, respectively. The batch experiments further showed that Fe(3+) dosage changed the final products of sulfate reduction with sulfide accounting for only 54% of the sulfate reduced. The other products could not be confirmed, but were not dissolved inorganic sulfur species such as sulfite or thiosulfate. The results suggest the addition of Fe(3+) at upstream locations would minimize the ferric salts required for achieving the same level of sulfide removal. Fe(3+) dosing could also substantially reduce the formation of methane, a potent greenhouse gas, in sewers. PMID:19576610

  14. The genome sequence of the anaerobic, sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough

    Microsoft Academic Search

    Rekha Seshadri; Shelley A Haveman; Christopher L Hemme; Ian T Paulsen; James F Kolonay; Jonathan A Eisen; Barbara Methe; Lauren M Brinkac; Sean C Daugherty; Robert T Deboy; Robert J Dodson; A Scott Durkin; Ramana Madupu; William C Nelson; Steven A Sullivan; Derrick Fouts; Daniel H Haft; Jeremy Selengut; Jeremy D Peterson; Tanja M Davidsen; Nikhat Zafar; Liwei Zhou; Diana Radune; George Dimitrov; Mark Hance; Kevin Tran; Hoda Khouri; John Gill; Terry R Utterback; Tamara V Feldblyum; Judy D Wall; Gerrit Voordouw; Claire M Fraser; John F Heidelberg

    2004-01-01

    Desulfovibrio vulgaris Hildenborough is a model organism for studying the energy metabolism of sulfate-reducing bacteria (SRB) and for understanding the economic impacts of SRB, including biocorrosion of metal infrastructure and bioremediation of toxic metal ions. The 3,570,858 base pair (bp) genome sequence reveals a network of novel c-type cytochromes, connecting multiple periplasmic hydrogenases and formate dehydrogenases, as a key feature

  15. Inhibition of sulfate-reducing and methanogenic activities of anaerobic sewer biofilms by ferric iron dosing

    Microsoft Academic Search

    Lishan Zhang; Jürg Keller; Zhiguo Yuan

    2009-01-01

    Ferric iron is commonly used for sulfide precipitation in sewers, thus achieving corrosion and odour control. Its impact on the activities of sulfate-reducing bacteria and methanogens in anaerobic sewer biofilms is investigated in this study. Two lab-scale rising main sewer systems fed with real sewage were operated for 8 months. One received Fe3+ dosage (experimental system) and the other was

  16. Growth of desulfovibrio in lactate or ethanol media low in sulfate in association with H2-utilizing methanogenic bacteria.

    PubMed

    Bryant, M P; Campbell, L L; Reddy, C A; Crabill, M R

    1977-05-01

    In the analysis of an ethanol-CO(2) enrichment of bacteria from an anaerobic sewage digestor, a strain tentatively identified as Desulfovibrio vulgaris and an H(2)-utilizing methanogen resembling Methanobacterium formicicum were isolated, and they were shown to represent a synergistic association of two bacterial species similar to that previously found between S organism and Methanobacterium strain MOH isolated from Methanobacillus omelianskii. In lowsulfate media, the desulfovibrio produced acetate and H(2) from ethanol and acetate, H(2), and, presumably, CO(2) from lactate; but growth was slight and little of the energy source was catabolized unless the organism was combined with an H(2)-utilizing methanogenic bacterium. The type strains of D. vulgaris and Desulfovibrio desulfuricans carried out the same type of synergistic growth with methanogens. In mixtures of desulfovibrio and strain MOH growing on ethanol, lactate, or pyruvate, diminution of methane produced was stoichiometric with the moles of sulfate added, and the desulfovibrios grew better with sulfate addition. The energetics of the synergistic associations and of the competition between the methanogenic system and sulfate-reducing system as sinks for electrons generated in the oxidation of organic materials such as ethanol, lactate, and acetate are discussed. It is suggested that lack of availability of H(2) for growth of methanogens is a major factor in suppression of methanogenesis by sulfate in natural ecosystems. The results with these known mixtures of bacteria suggest that hydrogenase-forming, sulfate-reducing bacteria could be active in some methanogenic ecosystems that are low in sulfate. PMID:879775

  17. Sulfation of keratan sulfate proteoglycan reduces radiation-induced apoptosis in human Burkitt's lymphoma cell lines.

    PubMed

    Nakayama, Fumiaki; Umeda, Sachiko; Ichimiya, Tomomi; Kamiyama, Shin; Hazawa, Masaharu; Yasuda, Takeshi; Nishihara, Shoko; Imai, Takashi

    2013-01-16

    This study focuses on clarifying the contribution of sulfation to radiation-induced apoptosis in human Burkitt's lymphoma cell lines, using 3'-phosphoadenosine 5'-phosphosulfate transporters (PAPSTs). Overexpression of PAPST1 or PAPST2 reduced radiation-induced apoptosis in Namalwa cells, whereas the repression of PAPST1 expression enhanced apoptosis. Inhibition of PAPST slightly decreased keratan sulfate (KS) expression, so that depletion of KS significantly increased radiation-induced apoptosis. In addition, the repression of all three N-acetylglucosamine-6-O-sulfotransferases (CHST2, CHST6, and CHST7) increased apoptosis. In contrast, PAPST1 expression promoted the phosphorylation of p38 MAPK and Akt in irradiated Namalwa cells. These findings suggest that 6-O-sulfation of GlcNAc residues in KS reduces radiation-induced apoptosis of human Burkitt's lymphoma cells. PMID:23238079

  18. 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.

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

    SciTech Connect

    Coates, J.D.; Woodward, J.C.; Phillips, E.J.P. [Geological Survey, Reston, VA (United States)] [Geological Survey, Reston, VA (United States); Anderson, R.T.; Lovley, D.R. [Univ. of Massachusetts, Amherst, MA (United States)] [Univ. of Massachusetts, Amherst, MA (United States)

    1996-09-01

    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. 36 refs., 7 figs.

  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. Isolation and characterization of a sulfate-reducing bacterium that anaerobically degrades alkanes.

    PubMed

    So, C M; Young, L Y

    1999-07-01

    An alkane-degrading, sulfate-reducing bacterial strain, AK-01, was isolated from an estuarine sediment with a history of chronic petroleum contamination. The bacterium is a short, nonmotile, non-spore-forming, gram-negative rod. It is mesophilic and grows optimally at pH 6.9 to 7.0 and at an NaCl concentration of 1%. Formate, fatty acids (C4 to C16) and hydrogen were readily utilized as electron donors. Sulfate, sulfite, and thiosulfate were used as electron acceptors, but sulfur, nitrite, and nitrate were not. Phenotypic characterization and phylogenetic analysis based on 16S rRNA gene sequence indicate that AK-01 is most closely related to the genera Desulfosarcina, Desulfonema, and Desulfococcus in the delta subdivision of the class Proteobacteria. It is phenotypically and phylogenetically different from strains Hxd3 and TD3, two previously reported isolates of alkane-degrading, sulfate-reducing bacteria. The alkanes tested to support growth of AK-01 had chain lengths of C13 to C18. 1-Alkenes (C15 and C16) and 1-alkanols (C15 and C16) also supported growth. The doubling time for growth on hexadecane was 3 days, about four times longer than that for growth on hexadecanoate. Mineralization of hexadecane was indicated by the recovery of 14CO2 from cultures grown on [1-14C]hexadecane. Degradation of hexadecane was dependent on sulfate reduction. The stoichiometric ratio (as moles of sulfate reduced per mole of hexadecane degraded) was 10.6, which is very close to the theoretical ratio of 12.25, assuming a complete oxidation to CO2. Anaerobic alkane degradation by sulfate reducers may be a more widespread phenomenon than was previously thought. PMID:10388691

  2. Microbial community structures and in situ sulfate-reducing and sulfur-oxidizing activities in biofilms developed on mortar specimens in a corroded sewer system

    Microsoft Academic Search

    Hisashi Satoh; Mitsunori Odagiri; Tsukasa Ito; Satoshi Okabe

    2009-01-01

    Microbially induced concrete corrosion (MICC) caused by sulfuric acid attack in sewer systems has been a serious problem for a long time. A better understanding of microbial community structures of sulfate-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB) and their in situ activities is essential for the efficient control of MICC. In this study, the microbial community structures and the in

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

    PubMed

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

    2012-06-01

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

  4. 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 ?g 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 ? 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.

  5. Anaerobic naphthalene degradation by sulfate-reducing Desulfobacteraceae from various anoxic aquifers.

    PubMed

    Kümmel, Steffen; Herbst, Florian-Alexander; Bahr, Arne; Duarte, Márcia; Pieper, Dietmar H; Jehmlich, Nico; Seifert, Jana; von Bergen, Martin; Bombach, Petra; Richnow, Hans H; Vogt, Carsten

    2015-03-01

    Polycyclic aromatic hydrocarbons (PAH) are widespread and persistent environmental contaminants, especially in oxygen-free environments. The occurrence of anaerobic PAH-degrading bacteria and their underlying metabolic pathways are rarely known. In this study, PAH degraders were enriched in laboratory microcosms under sulfate-reducing conditions using groundwater and sediment samples from four PAH-contaminated aquifers. Five enrichment cultures were obtained showing sulfate-dependent naphthalene degradation. Mineralization of naphthalene was demonstrated by the formation of sulfide concomitant with the depletion of naphthalene and the development of (13)C-labeled CO2 from [(13)C6]-naphthalene. 16S rRNA gene and metaproteome analyses revealed that organisms related to Desulfobacterium str. N47 were the main naphthalene degraders in four enrichment cultures. Protein sequences highly similar to enzymes of the naphthalene degradation pathway of N47 were identified, suggesting that naphthalene was activated by a carboxylase, and that the central metabolite 2-naphthoyl-CoA was further reduced by two reductases. The data indicate an importance of members of the family Desulfobacteraceae for naphthalene degradation under sulfate-reducing conditions in freshwater environments. PMID:25764566

  6. Anaerobic degradation of ethylbenzene by a new type of marine sulfate-reducing bacterium.

    PubMed

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

    2003-02-01

    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

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

    PubMed

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

    2013-10-01

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

  9. 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

  10. Engineering Dissimilatory metal-reducing bacteria (DMRB) are a

    E-print Network

    Chemical Engineering Dissimilatory metal-reducing bacteria (DMRB) are a class of microorganisms that inhabit many subsurface environments including marine sediments. They occupy a distinct metabolic niche

  11. 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 ?M). 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

  12. Successional Development of Sulfate-Reducing Bacterial Populations and Their Activities in a Wastewater Biofilm Growing under Microaerophilic Conditions

    Microsoft Academic Search

    Tsukasa Ito; Satoshi Okabe; Hisashi Satoh; Yoshimasa Watanabe

    2002-01-01

    A combination of fluorescence in situ hybridization, microprofiles, denaturing gradient gel electrophoresis of PCR-amplified 16S ribosomal DNA fragments, and 16S rRNA gene cloning analysis was applied to inves- tigate successional development of sulfate-reducing bacteria (SRB) community structure and in situ sulfide production activity within a biofilm growing under microaerophilic conditions (dissolved oxygen concentration in the bulk liquid was in the

  13. The anaerobic treatment of sulfate containing wastewater

    Microsoft Academic Search

    A. Visser

    1995-01-01

    In the anaerobic treatment of sulfate containing wastewater sulfate reducing bacteria (SRB) will compete with methanogenic- (MB) and acetogenic bacteria (AB) for the available substrates such as hydrogen, acetate, propionate and butyrate. The outcome of this competition will determine the endproduct of the anaerobic mineralisation proces: methane or sulfide.The occurrence of the sulfate reduction proces is often considered unwanted due

  14. [Activity and structure of the sulfate-reducing bacterial community in the sediments of the southern part of Lake Baikal].

    PubMed

    Pimenov, N V; Zakharova, E E; Briukhanov, A L; Korneeva, V A; Kuznetsov, B B; Turova, T P; Pogodaeva, T V; Kalmychkov, G V; Zemskaia, T I

    2014-01-01

    The rates of sulfate reduction (SR) and the diversity of sulfate-reducing bacteria (SRB) were studied in the sediments of the Posol'skaya banka elevation in the southern part of Lake Baikal. SR rates varied from 1.2 to 1641 nmol/(dm3 day), with high rates (> 600 nmol/(dm3 day)) observed at both deep-water stations and in subsurface silts. Integral SR rates calculated for the uppermost 50 cm of the sediments were higher for gas-saturated and gas hydrate-bearing sediments than in those with low methane content. Enrichment SRB cultures were obtained in Widdel medium for freshwater SRB. Analysis of the 16S rRNA gene fragments from clone libraries obtained from the enrichments revealed the presence of SRB belonged to Desulfosporosinus genus, with D. lacus as the most closely related member (capable of sulfate, sulfite, and thiosulfate reduction), as well as members of the order Clostridiales. PMID:25423722

  15. [Activity and structure of the sulfate-reducing bacterial community in the sediments of the southern part of Lake Baikal].

    PubMed

    2014-01-01

    The rates of sulfate reduction (SR) and the diversity of sulfate-reducing bacteria (SRB) were studied in the sediments of the Posol'skaya banka elevation in the southern part of Lake Baikal. SR rates varied from 1.2 to 1641 nmol/(dm3 day), with high rates (> 600 nmol/(dm3 day)) observed at both deep-water stations and in subsurface silts. Integral SR rates calculated for the uppermost 50 cm of the sediments were higher for gas-saturated and gas hydrate-bearing sediments than in those with low methane content. Enrichment SRB cultures were obtained in Widdel medium for freshwater SRB. Analysis of the 16S rRNA gene fragments from clone libraries obtained from the enrichments revealed the presence of SRB belonged to Desulfosporosinus genus, with D. lacus as the most closely related member (capable of sulfate, sulfite, and thiosulfate reduction), as well as members of the order Clostridiales. PMID:25507445

  16. Diversity and Composition of Sulfate and Sulfite-Reducing Prokaryotes as Affected by Marine-Freshwater Gradient and Sulfate Availability

    Microsoft Academic Search

    Lan-Feng Fan; Sen-Lin Tang; Chang-Po Chen; Hwey-Lian Hsieh

    Sulfate- and sulfite-reducing prokaryotes (SSRP) communities play a key role in both sulfur and carbon cycles. In estuarine\\u000a ecosystems, sulfate concentrations change with tides and could be limited in tidal freshwater reach or deep sediments. In\\u000a a subtropical estuary of northern Taiwan in December 2007, we examined the compositional changes of SSRP communities. We examined\\u000a three sites: from the lower

  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. Effects of biocides on gene expression in the sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough.

    PubMed

    Lee, Meng-Hsin Phoebe; Caffrey, Sean M; Voordouw, Johanna K; Voordouw, Gerrit

    2010-07-01

    Although sulfate-reducing bacteria (SRB), such as Desulfovibrio vulgaris Hildenborough (DvH) are often eradicated in oil and gas operations with biocides, such as glutaraldehyde (Glut), tetrakis (hydroxymethyl) phosphonium sulfate (THPS), and benzalkonium chloride (BAC), their response to these agents is not well known. Whole genome microarrays of D. vulgaris treated with biocides well below the minimum inhibitory concentration showed that 256, 96, and 198 genes were responsive to Glut, THPS, and BAC, respectively, and that these three commonly used biocides affect the physiology of the cell quite differently. Glut induces expression of genes required to degrade or refold proteins inactivated by either chemical modification or heat shock, whereas BAC appears to target ribosomal structure. THPS appears to primarily affect energy metabolism of SRB. Mutants constructed for genes strongly up-regulated by Glut, were killed by Glut to a similar degree as the wild type. Hence, it is difficult to achieve increased sensitivity to this biocide by single gene mutations, because Glut affects so many targets. Our results increase understanding of the biocide's mode of action, allowing a more intelligent combination of mechanistically different agents. This can reduce stress on budgets for chemicals and on the environment. PMID:20437234

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

    PubMed Central

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

    2012-01-01

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

  20. 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

  1. 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.

  2. [Analysis of microbial community variation in the domestication process of sludge in a sulfate-reducing reactor].

    PubMed

    Zeng, Guo-Qu; Jia, Xiao-Shan; Zheng, Xiao-Hong; Yang, Li-Ping; Sun, Guo-Ping

    2014-11-01

    The variations of microbial community in the sludge of sulfate-reducing UASB during domestication period were analyzed by PCR-DGGE technique. The results showed that the diversity of microbial community was strongly related to the sulfate reduction and COD removal performance. The sulfate reduction rate of the reactor was about 95% when the Shannon index of microbial community was higher than 3.45. The preponderant bands in DGGE figure were excised and cloned, and the sequencing analysis indicated there were Firmicutes, Proteobacteria, Deinococcus-Thermus and Chloroflexi in the sludge, which accounted for 50.0%, 28.6% 14.3% and 7.1% of the total sequences of samples, respectively. The anaerobic fermentative bacteria of Clostridium sp. were predominant in the whole domestication period, but the predominant species was changing. Some anaerobic bacteria like Chloroflexi sp. and Geopsychrobacter sp. were detected to be dominant species, which then disappeared along with further domestication, but anaerobic bacteria Geobacter sp. became gradually predominant in the domestication process. Species of Desulfovibrio sp. were detected to be predominant only in the last two phases of domestication. PMID:25639102

  3. The influence of organic carbon on oxygen dynamics and bacterial sulfate reduction in inland shrimp ponds 

    E-print Network

    Suplee, Michael Wayne

    1995-01-01

    Experiments conducted in saline aquaculture ponds demonstrated that organic matter was the primary factor influencing sediment sulfate reduction rates. Changes in sediment oxygen demand (SOD), sulfate reduction rates, and sulfate reducing bacteria...

  4. 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.

  5. Diversity and composition of sulfate- and sulfite-reducing prokaryotes as affected by marine-freshwater gradient and sulfate availability.

    PubMed

    Fan, Lan-Feng; Tang, Sen-Lin; Chen, Chang-Po; Hsieh, Hwey-Lian

    2012-01-01

    Sulfate- and sulfite-reducing prokaryotes (SSRP) communities play a key role in both sulfur and carbon cycles. In estuarine ecosystems, sulfate concentrations change with tides and could be limited in tidal freshwater reach or deep sediments. In a subtropical estuary of northern Taiwan in December 2007, we examined the compositional changes of SSRP communities. We examined three sites: from the lower estuarine brackish-water reach (site GR and mangrove vegetation site, GM) to the upper estuarine tidal freshwater reach (site HR), as well as from surface to a 50-cm depth. The partial sequence of sulfite reductase (dsrB) genes was used as a molecular marker of SSRP, linked to polymerase chain reaction and denaturing gradient gel electrophoresis (DGGE) techniques. SSRP communities of the DGGE profiles varied with sites according to one-way analyses of similarities (Global R?=?0.69, P?=?0.001). Using cluster analysis, the DGGE profile was found to show site-specific clusters and a distinct depth zonation (five, six, and two SSRP communities at the GM, GR, and HR sites, respectively). SSRP composition was highly correlated to the combination of salinity, reduced sulfur, and total organic carbon contents (BIO-ENV analysis, r ( s )?=?0.56). After analyzing a total of 35 dsrB sequences in the DGGE gel, six groups with 15 phylotypes were found, which were closely related to marine-freshwater gradient. Moreover, sequences neighboring sulfite-reducing prokaryotes were observed, in addition to those affiliated to sulfate-reducing prokaryotes. Four phylotypes harvested in HR resembled the genus Desulfitobacterium, a sulfite-reducing prokaryote, which failed to use sulfate as an electron acceptor and were active in freshwater and sulfate-limited habitat. The other five phylotypes in the HR reach belonged to the sulfate-reducing prokaryotes of the genera Desulfatiferula, Desulfosarcina, Desulfovibrio, and Desulfotomaculum, which appeared to tolerate low salinity and low sulfate supply. SSRP phylotypes at the mangrove-vegetated GM site (five phylotypes in two groups) were phylogenetically less diverse, when compared with those at the non-mangrove-vegetated GR site (three phylotypes in three groups) and the tidally influenced freshwater HR site (nine phylotypes in five groups). Phylotypes found at GR and GM were all affiliated to marine sulfate-reducing prokaryote strains of the genera Desulfofaba, Desulfobotulus, Desulfatiferula, Desulfosarcina, and Desulfotomaculum. Notably, a phylotype recorded in the surface sediment at GR resembled the genus Desulfobulbus, which was recorded from freshwater environment consisting of the freshwater input at GR during ebb tides. PMID:21785985

  6. 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

  7. Universal Immunoprobe for (Per)Chlorate-Reducing Bacteria

    PubMed Central

    O'Connor, Susan M.; Coates, John D.

    2002-01-01

    Recent studies in our lab have demonstrated the ubiquity and diversity of microorganisms which couple growth to the reduction of chlorate or perchlorate [(per)chlorate] under anaerobic conditions. We identified two taxonomic groups, the Dechloromonas and the Dechlorosoma groups, which represent the dominant (per)chlorate-reducing bacteria (ClRB) in the environment. As part of these studies we demonstrated that chlorite dismutation is a central step in the reductive pathway of (per)chlorate that is common to all ClRB and which is mediated by the enzyme chlorite dismutase (CD). Initial studies on CD suggested that this enzyme is highly conserved among the ClRB, regardless of their phylogenetic affiliation. As such, this enzyme makes an ideal target for a probe specific for these organisms. Polyclonal antibodies were commercially raised against the purified CD from the ClRB Dechloromonas agitata strain CKB. The obtained antiserum was deproteinated by ammonium sulfate precipitation, and the antigen binding activity was assessed using dot blot analysis of a serial dilution of the antiserum. The titers obtained with purified CD indicated that the antiserum had a high affinity for the CD enzyme, and activity was observed in dilutions as low as 10?6 of the original antiserum. The antiserum was active against both cell lysates and whole cells of D. agitata, but only if the cells were grown anaerobically with (per)chlorate. No response was obtained with aerobically grown cultures. In addition to D. agitata, dot blot analysis employed with both whole-cell suspensions and cell lysates of several diverse ClRB representing the alpha, beta, and gamma subclasses of Proteobacteria tested positive regardless of phylogenetic affiliation. Interestingly, the dot blot response obtained for each of the ClRB cell lysates was different, suggesting that there may be some differences in the antigenic sites of the CD protein produced in these organisms. In general, no reactions were observed with cells or cell lysates of the organisms closely related to the ClRB which could not grow by (per)chlorate reduction. These studies have resulted in the development of a highly specific and sensitive immunoprobe based on the commonality of the CD enzyme in ClRB which can be used to assess dissimilatory (per)chlorate-reducing populations in environmental samples regardless of their phylogenetic affiliations. PMID:12039773

  8. 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

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

    2015-01-01

    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. PMID:25767232

  9. An ultracapacitor circuit for reducing sulfation in lead acid batteries for Mild Hybrid Electric Vehicles

    Microsoft Academic Search

    Adam W. Stienecker; Thomas Stuart; Cyrus Ashtiani

    2006-01-01

    The nickel metal hydride (NiMH) batteries used in most hybrid electric vehicles (HEVs) provide satisfactory performance, but are quite expensive. In spite of their lower energy density, lead acid batteries would be much more economical except they are prone to sulfation in HEV applications. However, sulfation can be greatly reduced by a circuit that uses an ultracapacitor in conjunction with

  10. 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

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

    SciTech Connect

    Anderson, Iain [U.S. Department of Energy, Joint Genome Institute; Saunders, Elizabeth H [Los Alamos National Laboratory (LANL); Lapidus, Alla L. [U.S. Department of Energy, Joint Genome Institute; Nolan, Matt [U.S. Department of Energy, Joint Genome Institute; Lucas, Susan [U.S. Department of Energy, Joint Genome Institute; Tice, Hope [U.S. Department of Energy, Joint Genome Institute; Glavina Del Rio, Tijana [U.S. Department of Energy, Joint Genome Institute; Cheng, Jan-Fang [U.S. Department of Energy, Joint Genome Institute; Han, Cliff [Los Alamos National Laboratory (LANL); Tapia, Roxanne [Los Alamos National Laboratory (LANL); Goodwin, Lynne A. [Los Alamos National Laboratory (LANL); Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Liolios, Konstantinos [U.S. Department of Energy, Joint Genome Institute; Mavromatis, K [U.S. Department of Energy, Joint Genome Institute; Pagani, Ioanna [U.S. Department of Energy, Joint Genome Institute; Ivanova, N [U.S. Department of Energy, Joint Genome Institute; Mikhailova, Natalia [U.S. Department of Energy, Joint Genome Institute; Pati, Amrita [U.S. Department of Energy, Joint Genome Institute; Chen, Amy [U.S. Department of Energy, Joint Genome Institute; Palaniappan, Krishna [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL; Hauser, Loren John [ORNL; Jeffries, Cynthia [Oak Ridge National Laboratory (ORNL); Chang, Yun-Juan [ORNL; Brambilla, Evelyne-Marie [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Rohde, Manfred [HZI - Helmholtz Centre for Infection Research, Braunschweig, Germany; Spring, Stefan [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Goker, Markus [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Detter, J. Chris [U.S. Department of Energy, Joint Genome Institute; Woyke, Tanja [U.S. Department of Energy, Joint Genome Institute; Bristow, James [U.S. Department of Energy, Joint Genome Institute; Eisen, Jonathan [U.S. Department of Energy, Joint Genome Institute; Markowitz, Victor [U.S. Department of Energy, Joint Genome Institute; Hugenholtz, Philip [U.S. Department of Energy, Joint Genome Institute; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Klenk, Hans-Peter [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany

    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.

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

    PubMed

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

    2015-01-01

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

  13. 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.

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

    PubMed

    Sánchez-Andrea, Irene; Stams, Alfons J M; Hedrich, Sabrina; ?ancucheo, 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

  15. Analysis of the Sulfate-Reducing Bacterial and Methanogenic Archaeal Populations in Contrasting Antarctic Sediments

    PubMed Central

    Purdy, K. J.; Nedwell, D. B.; Embley, T. M.

    2003-01-01

    The distribution and activity of communities of sulfate-reducing bacteria (SRB) and methanogenic archaea in two contrasting Antarctic sediments were investigated. Methanogenesis dominated in freshwater Lake Heywood, while sulfate reduction dominated in marine Shallow Bay. Slurry experiments indicated that 90% of the methanogenesis in Lake Heywood was acetoclastic. This finding was supported by the limited diversity of clones detected in a Lake Heywood archaeal clone library, in which most clones were closely related to the obligate acetate-utilizing Methanosaeta concilii. The Shallow Bay archaeal clone library contained clones related to the C1-utilizing Methanolobus and Methanococcoides and the H2-utilizing Methanogenium. Oligonucleotide probing of RNA extracted directly from sediment indicated that archaea represented 34% of the total prokaryotic signal in Lake Heywood and that Methanosaeta was a major component (13.2%) of this signal. Archaea represented only 0.2% of the total prokaryotic signal in RNA extracted from Shallow Bay sediments. In the Shallow Bay bacterial clone library, 10.3% of the clones were SRB-like, related to Desulfotalea/Desulforhopalus, Desulfofaba, Desulfosarcina, and Desulfobacter as well as to the sulfur and metal oxidizers comprising the Desulfuromonas cluster. Oligonucleotide probes for specific SRB clusters indicated that SRB represented 14.7% of the total prokaryotic signal, with Desulfotalea/Desulforhopalus being the dominant SRB group (10.7% of the total prokaryotic signal) in the Shallow Bay sediments; these results support previous results obtained for Arctic sediments. Methanosaeta and Desulfotalea/Desulforhopalus appear to be important in Lake Heywood and Shallow Bay, respectively, and may be globally important in permanently low-temperature sediments. PMID:12788715

  16. Solubilization of plutonium hydrous oxide by iron-reducing bacteria

    Microsoft Academic Search

    Patricia A. Rusin; Leticia Quintana; James R. Brainard; B. A. Strietelmeler; C. Drew Tait; Scott A. Ekberg; Phillip D. Palmer; Thomas W. Newton; David L. Clark

    1994-01-01

    The removal of plutonium from soils id challenging because of its strong sorption to soils and limited solubility, Microbial reduction of metals is known to affect the speciation and solubility of sparingly soluble metals in the environment, notably iron and manganese. The similarity in reduction potential for [alpha]-FeOOH(s) and hydrous PuO[sub 2](s) suggests that iron-reducing bacteria may also reduce and

  17. 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.

  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 ?18O 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 ?18O 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. 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

  20. 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

  1. SUBSTRATE DEGRADATION AND METAL REMOVAL PERFORMANCE OF A 1,500- GALLON SULFATE-REDUCING BIOREACTOR FOR MINING-INFLUENCED WATER TREATMENT1

    Microsoft Academic Search

    Ana Ruiz; Linda Figueroa; Marek Zaluski; Diana Bless

    The successful long-term operation and sustainability of passive systems for the treatment of mining influenced water (MIW) affected by metals and acidity has been challenged by a lack of understanding on organic substrate design. Metabolic activity of sulfate-reducing bacteria (SRB) in bioreactors produces H2S that precipitates dissolved metals, and it is the main mechanism that removes metals from solution. Fermentation

  2. Fe(III)EDTA and Fe(II)EDTA-NO reduction by a sulfate reducing bacterium in NO and SO? scrubbing liquor.

    PubMed

    Chen, Mingxiang; Zhou, Jiti; Zhang, Yu; Wang, Xiaojun; Shi, Zhuang; Wang, Xiaowei

    2015-03-01

    A viable process concept, based on NO and SO2 absorption into an alkaline Fe(II)EDTA (EDTA: ethylenediaminetetraacetic acid) solution in a scrubber combined with biological reduction of the absorbed SO2 utilizing sulfate reducing bacteria (SRB) and regeneration of the scrubbing liquor in a single bioreactor, was developed. The SRB, Desulfovibrio sp. CMX, was used and its sulfate reduction performances in FeEDTA solutions and Fe(II)EDTA-NO had been investigated. In this study, the detailed regeneration process of Fe(II)EDTA solution, which contained Fe(III)EDTA and Fe(II)EDTA-NO reduction processes in presence of D. sp. CMX and sulfate, was evaluated. Fe(III)EDTA and Fe(II)EDTA-NO reduction processes were primarily biological, even if Fe(III)EDTA and Fe(II)EDTA-NO could also be chemically convert to Fe(II)EDTA by biogenic sulfide. Regardless presence or absence of sulfate, more than 87 % Fe(III)EDTA and 98 % Fe(II)EDTA-NO were reduced in 46 h, respectively. Sulfate and Fe(III)EDTA had no affection on Fe(II)EDTA-NO reduction. Sulfate enhanced final Fe(III)EDTA reduction. Effect of Fe(III)EDTA on Fe(II)EDTA-NO reduction rate was more obvious than effect of sulfate on Fe(II)EDTA-NO reduction rate before 8 h. To overcome toxicity of Fe(II)EDTA-NO on SRB, Fe(II)EDTA-NO was reduced first and the reduction of Fe(III)EDTA and sulfate occurred after 2 h. First-order Fe(II)EDTA-NO reduction rate and zero-order Fe(III)EDTA reduction rate were detected respectively before 8 h. PMID:25649204

  3. 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. [Stanford Univ., CA (United States); LeBron, C.A. [Naval Facilities Engineering Service Center, Port Hueneme, CA (United States)

    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.

  4. 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. [New Mexico State Univ., Las Cruces, NM (United States)

    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.

  5. Sulfate reduction below the sulfate-methane transition in Black Sea sediments

    NASA Astrophysics Data System (ADS)

    Holmkvist, Lars; Kamyshny, Alexey, Jr.; Vogt, Christoph; Vamvakopoulos, Kyriakos; Ferdelman, Timothy G.; Jørgensen, Bo Barker

    2011-05-01

    A sudden increase in salinity about 7000 years ago caused a shift in the deposited sediments of the Black Sea from limnic to brackish-marine. Due to the development of an anoxic deep water basin and a relatively high sulfate concentration, organic matter is mineralized primarily through sulfate reduction in modern Black Sea sediments. Earlier studies showed that sulfate-reducing bacteria are abundant within the limnic sub-surface sediment in spite of extremely low concentrations of sulfate and organic carbon. A main objective of the present study was therefore to understand the depth distribution of sulfate reduction across the different sediment units, even deep below the sulfate-methane transition. Our study combined experimental measurements of sulfate reduction using 35S radiotracer with analyses of sulfur and iron geochemistry in pore water and sediment. Potential sulfate reduction rates were measured with 35S in sediment samples that were amended with sulfate and organic substrates and incubated in time-series up to 48 h. Sulfate reduction could thereby be detected and quantified at depths where concentrations of sulfate were otherwise too low to enable calculation of the rates. The results demonstrate that sulfate-reducing bacteria are active several meters below the sulfate-methane transition in Black Sea sediments. The cryptic sulfate reduction below the sulfate-methane transition may be driven by sulfate produced from re-oxidation of reduced sulfur species with oxidized iron minerals buried in the deep limnic sediment.

  6. The use of seaweed and sugarcane bagasse for the biological treatment of metal-contaminated waters under sulfate-reducing conditions.

    PubMed

    Gonçalves, Márcia Monteiro Machado; de Oliveira Mello, Luiz Antonio; da Costa, Antonio Carlos Augusto

    2008-03-01

    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. PMID:18401756

  7. Metabolic Engineering of an Aerobic Sulfate Reduction Pathway and Its Application to Precipitation of Cadmium on the Cell Surface

    Microsoft Academic Search

    CLIFFORD L. WANG; PRIYA D. MARATUKULAM; AMY M. LUM; DOUGLAS S. CLARK; J. D. Keasling

    2000-01-01

    The conversion of sulfate to an excess of free sulfide requires stringent reductive conditions. Dissimilatory sulfate reduction is used in nature by sulfate-reducing bacteria for respiration and results in the conversion of sulfate to sulfide. However, this dissimilatory sulfate reduction pathway is inhibited by oxygen and is thus limited to anaerobic environments. As an alternative, we have metabolically engineered a

  8. Prokaryotic community structure and sulfate reducer activity in water from high-temperature oil reservoirs with and without nitrate treatment.

    PubMed

    Gittel, Antje; Sørensen, Ketil Bernt; Skovhus, Torben Lund; Ingvorsen, Kjeld; Schramm, Andreas

    2009-11-01

    Sulfate-reducing prokaryotes (SRP) cause severe problems like microbial corrosion and reservoir souring in seawater-injected oil production systems. One strategy to control SRP activity is the addition of nitrate to the injection water. Production waters from two adjacent, hot (80 degrees C) oil reservoirs, one with and one without nitrate treatment, were compared for prokaryotic community structure and activity of SRP. Bacterial and archaeal 16S rRNA gene analyses revealed higher prokaryotic abundance but lower diversity for the nitrate-treated field. The 16S rRNA gene clone libraries from both fields were dominated by sequences affiliated with Firmicutes (Bacteria) and Thermococcales (Archaea). Potential heterotrophic nitrate reducers (Deferribacterales) were exclusively found at the nitrate-treated field, possibly stimulated by nitrate addition. Quantitative PCR of dsrAB genes revealed that archaeal SRP (Archaeoglobus) dominated the SRP communities, but with lower relative abundance at the nitrate-treated site. Bacterial SRP were found in only low abundance at both sites and were nearly exclusively affiliated with thermophilic genera (Desulfacinum and Desulfotomaculum). Despite the high abundance of archaeal SRP, no archaeal SRP activity was detected in [(35)S]sulfate incubations at 80 degrees C. Sulfate reduction was found at 60 degrees C in samples from the untreated field and accompanied by the growth of thermophilic bacterial SRP in batch cultures. Samples from the nitrate-treated field generally lacked SRP activity. These results indicate that (i) Archaeoglobus can be a major player in hot oil reservoirs, and (ii) nitrate may act in souring control-not only by inhibiting SRP, but also by changing the overall community structure, including the stimulation of competitive nitrate reducers. PMID:19801479

  9. 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.

  10. ENZYMATIC BASIS FOR ASSIMILATORY AND DISSIMILATORY SULFATE REDUCTION

    PubMed Central

    Peck, H. D.

    1961-01-01

    Peck, H. D., Jr. (Oak Ridge National Laboratory, Oak Ridge, Tenn.). Enzymatic basis for assimilatory and dissimilatory sulfate reduction. J. Bacteriol. 82: 933–939. 1961.—Two pathways for the reduction of sulfate to sulfite in bacteria have been previously described. The substrate for sulfate reduction by extracts of yeast is 3?-phosphoadenosine-5?-phosphosulfate (PAPS) and, in contrast, the substrate for sulfate reduction in extracts of Desulfovibrio desulfuricans is adenosine-5?-phosphosulfate (APS). The enzymes catalyzing these reductions have been termed PAPS-reductase and APS-reductase, respectively. Since yeasts are “assimilatory sulfate reducers”, i.e., reduce only enough sulfate to satisfy nutritional requirements for sulfur, and D. desulfuricans is a “dissimilatory sulfate reducer”, i.e., utilizes sulfate as its terminal electron acceptor in anaerobic respiration, the pathway of sulfate reduction was determined in 25 microorganisms to ascertain whether there is a correlation between the pathway of sulfate reduction and the physiological role of sulfate in the metabolism of bacteria. Assimilatory sulfate reducers reduced sulfate in the form of PAPS, and, with one exception, APS-reductase was found only in dissimilatory sulfate reducers. APS-reductase was also found in the Thiobacilli in high specific activity and is involved in the oxidation of reduced sulfur compounds to sulfate. PMID:14484818

  11. 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...

  12. 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 ?-polysaccharides in the exterior and ?-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

  13. Genome sequence of Desulfobacterium autotrophicum HRM2, a marine sulfate reducer oxidizing organic carbon completely to carbon dioxide

    PubMed Central

    Strittmatter, Axel W; Liesegang, Heiko; Rabus, Ralf; Decker, Iwona; Amann, Judith; Andres, Sönke; Henne, Anke; Fricke, Wolfgang Florian; Martinez-Arias, Rosa; Bartels, Daniela; Goesmann, Alexander; Krause, Lutz; Pühler, Alfred; Klenk, Hans-Peter; Richter, Michael; Schüler, Margarete; Glöckner, Frank Oliver; Meyerdierks, Anke; Gottschalk, Gerhard; Amann, Rudolf

    2009-01-01

    Sulfate-reducing bacteria (SRB) belonging to the metabolically versatile Desulfobacteriaceae are abundant in marine sediments and contribute to the global carbon cycle by complete oxidation of organic compounds. Desulfobacterium autotrophicum HRM2 is the first member of this ecophysiologically important group with a now available genome sequence. With 5.6 megabasepairs (Mbp) the genome of Db. autotrophicum HRM2 is about 2 Mbp larger than the sequenced genomes of other sulfate reducers (SRB). A high number of genome plasticity elements (> 100 transposon-related genes), several regions of GC discontinuity and a high number of repetitive elements (132 paralogous genes Mbp?1) point to a different genome evolution when comparing with Desulfovibrio spp. The metabolic versatility of Db. autotrophicum HRM2 is reflected in the presence of genes for the degradation of a variety of organic compounds including long-chain fatty acids and for the Wood–Ljungdahl pathway, which enables the organism to completely oxidize acetyl-CoA to CO2 but also to grow chemolithoautotrophically. The presence of more than 250 proteins of the sensory/regulatory protein families should enable Db. autotrophicum HRM2 to efficiently adapt to changing environmental conditions. Genes encoding periplasmic or cytoplasmic hydrogenases and formate dehydrogenases have been detected as well as genes for the transmembrane TpII-c3, Hme and Rnf complexes. Genes for subunits A, B, C and D as well as for the proposed novel subunits L and F of the heterodisulfide reductases are present. This enzyme is involved in energy conservation in methanoarchaea and it is speculated that it exhibits a similar function in the process of dissimilatory sulfate reduction in Db. autotrophicum HRM2. PMID:19187283

  14. 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

  15. Anaerobic corrosion and bacterial sulfate reduction: Application for the purification of industrial wastewater

    Microsoft Academic Search

    Vladislav Somlev; Sava Tishkov

    1994-01-01

    Experiments that form the basis for a biotechnology for removing sulfate with immobilized sulfate?reducing bacteria from wastewaters polluted with sulfate, heavy metals, soluble forms of arsenic, and nitrates are described. The maximum rate of sulfate removal from wastewaters varied with the type of carrier used for cell immobilization. With the inert carrier dolomite, the maximum rate was 0.60 g m

  16. Dermatan Sulfate Epimerase 1-Deficient Mice Have Reduced Content and Changed Distribution of Iduronic Acids in Dermatan Sulfate and an Altered Collagen Structure in Skin?

    PubMed Central

    Maccarana, Marco; Kalamajski, Sebastian; Kongsgaard, Mads; Magnusson, S. Peter; Oldberg, Åke; Malmström, Anders

    2009-01-01

    Dermatan sulfate epimerase 1 (DS-epi1) and DS-epi2 convert glucuronic acid to iduronic acid in chondroitin/dermatan sulfate biosynthesis. Here we report on the generation of DS-epi1-null mice and the resulting alterations in the chondroitin/dermatan polysaccharide chains. The numbers of long blocks of adjacent iduronic acids are greatly decreased in skin decorin and biglycan chondroitin/dermatan sulfate, along with a parallel decrease in iduronic-2-O-sulfated-galactosamine-4-O-sulfated structures. Both iduronic acid blocks and iduronic acids surrounded by glucuronic acids are also decreased in versican-derived chains. DS-epi1-deficient mice are smaller than their wild-type littermates but otherwise have no gross macroscopic alterations. The lack of DS-epi1 affects the chondroitin/dermatan sulfate in many proteoglycans, and the consequences for skin collagen structure were initially analyzed. We found that the skin collagen architecture was altered, and electron microscopy showed that the DS-epi1-null fibrils have a larger diameter than the wild-type fibrils. The altered chondroitin/dermatan sulfate chains carried by decorin in skin are likely to affect collagen fibril formation and reduce the tensile strength of DS-epi1-null skin. PMID:19687302

  17. Stable carbon isotope fractionation by acetotrophic sulfur-reducing bacteria.

    PubMed

    Goevert, Dennis; Conrad, Ralf

    2010-02-01

    Acetate is the most important intermediate in anaerobic degradation of organic matter. The carbon isotope effects associated with the oxidation of acetate (epsilon(ac)) were examined for four acetotrophic sulfur reducers, Desulfuromonas acetoxidans, Desulfuromonas thiophila, Desulfurella acetivorans, and Hippea maritima. During the consumption of acetate and sulfur, acetate was enriched in (13)C by 11.5 and 11.2 per thousand in Desulfuromonas acetoxidans and Desulfuromonas thiophila, respectively. By contrast, isotope fractionation in D. acetivorans and H. maritima resulted in isotope enrichment factors of epsilon(ac)=-6.3 per thousand and -8.4 per thousand, respectively. These sulfur-reducing bacteria all metabolize acetate via the tricarboxylic acid cycle, but have different mechanisms for the initial activation of acetate. In Desulfuromonas acetoxidans, acetyl-CoA is formed by succinyl-CoA : acetate-CoA-transferase, and in D. acetivorans by acetate kinase and phosphate acetyltransferase. Hence, values of epsilon(ac) seem to be characteristic for the type of activation of acetate to acetyl-CoA in acetotrophic sulfur reducers. Summarizing epsilon(ac)-values in anaerobic acetotrophic microorganisms, it appears that isotope fractionation depends on the mechanism of acetate activation to acetyl-CoA, on the key enzyme of the acetate dissimilation pathway, and on the bioavailability of acetate, which all have to be considered when using delta(13)C of acetate in environmental samples for diagnosis of the involved microbial populations. PMID:20002180

  18. 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

  19. Halotolerant and Resistant to High pH Hydrogenase from Haloalkaliphilic Sulfate-Reducing Bacterium Desulfonatronum thiodismutans

    NASA Technical Reports Server (NTRS)

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

    2004-01-01

    Hydrogenase is the key enzyme of energetic metabolism in cells, it catalyzing the converse reaction of hydrogen oxidation and responsible for consumption and excretion of hydrogen in bacteria. Hydrogenases are proteins containing either Nickel and Iron, or the only Iron in theirs active center. Hydrogenases have been found in many microorganisms, such as Methanogenic, acetogenic, nitrogen-fixing, photosynthetic and sulfate-reducing bacteria that could utilize the hydrogen as energy source or use it as electron sink. Hydrogenases are subject for wide physiological, biochemical, physicochemical and genetic studies due to theirs abilities produce the molecular hydrogen as alternative source of pure energy. Notwithstanding on enough large quantity of works that deal with intracellular and extrasellular enzymes of halophilic bacteria, the data about hydrogenases and theirs functions of salts practically are absent. The study of hydrogenase in cell-free extracts of extremely halophilic eubacterium Acetohalobium mabaticum showed dramatic increasing activity of the enzyme at high concentrations of NaCl and KCI (close to saturated solution). Here we present the data of free-cells extracted hydrogenase from new haloalkaliphilic sulfate-reducing bacterium Desulfonatronum thiodismutans, which grow on highly miniralized carbonate-bicarbonate medium in salinity range 1 to 7 % and at pH 7.8 - 10.5. Studied enzyme was active in Concentration range from 0 to 4.3 M NaCl with optimum at 1.0 M NaCl. At 1.0 M NaCl the enzyme activity was increased on 20 %, but with changing concentration from 2.1 M to 3.4 M the activity decreased and was kept on constant level. NaHCO3 inhibited hydrogenase activity on more then 30 %. The maximum of enzyme activity was observed at pH 9.5 with limits 7.5 and 11.5 that practically equal to pH optimum of bacterial growth. Therefore the hydrogenase of Desulfanatronum thiodismutans is tolerant to high concentrations of sodium salts and it also resistant to high pH that make it the unique subject for different biochemical research and detects the possibility for biotechnological application.

  20. 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.

  1. Characterization of methyl mercury in dental wastewater and correlation with sulfate-reducing bacterial DNA.

    PubMed

    Zhao, Xiuhong; Rockne, Karl J; Drummond, James L; Hurley, Ryan K; Shade, Christopher W; Hudson, Robert J M

    2008-04-15

    Dental wastewater (DWW) was collected over two months from a 12-chair clinic and a single-chair office to identify conditions that may affect Hg methylation. DWW was settled for 24 h and samples were collected from the top and bottom of the supernatant to simulate a range of particles that may escape in-line traps. Total Hg spanned 5 orders of magnitude (0.02-5000 microM), following a log-normal distribution with p10, p50, and p90 concentration values of 0.24, 31 and 4000 microM, respectively; typically well in excess of free aqueous Hg solubility. Methyl Hg was present in high levels (2-270 nM), also following a log-normal distribution with p10, p50, and p90 concentration values of 2.8, 17, and 100 nM, respectively. There were no statistically significant differences (90% CI) in p50 methyl Hg or total Hg between the clinic and office. Methyl Hg was predicted from total Hg data by (+/- 95% CI): Log (Me-Hg) = 0.33 (+/- 0.06) x Log (T-Hg) - 2.27 (+/- 0.13). Total methyl Hg from DWW to U.S. wastewater collection systems is estimated to be 2-5 kg yr(-1). Equilibrium speciation modeling predicted that DWW Hg was primarily in sulfide-Hg complexes, except at high total Hg levels where organo-Hg complexes become significant. DNA extracts amplified by quantitative polymerase chain reaction with primers for total eubacteria and sulfate-reducing bacteria (SRB) indicated that the total eubacterial DNA was composed primarily of SRB, and highly significant correlations were found between methyl Hg and both amplified Desulfobacteraceae (p < 0.0001) and Desulfovibrionacaea DNA (p < 0.00001). Both are known Hg methylators. In marked contrast, there was no significant correlation between methyl Hg and amplified Desulfobulbus DNA, a genus generally not known to methylate Hg at high rates. These results strongly suggest that SRB are implicated in DWW Hg methylation. PMID:18497123

  2. 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

  3. Hydroxyapatite formation in the presence of proteoglycans of reduced sulfate content: Studies in the brachymorphic mouse

    Microsoft Academic Search

    Adele L Boskey; Michael Maresca; Bo Wikstrom; Ahnders Hjerpe

    1991-01-01

    Summary  Proteoglycans from the brachymorphic (bm\\/bm) mouse have a reduced sulfate content due to the impaired activity of adenosine\\u000a phosphosulfate phosphokinase in these animals. X-ray diffraction and infrared analyses of the mineral from the calcified cartilage\\u000a of the bm\\/bm mice demonstrate the presence of significantly larger and more perfect hydroxyapatite crystals of lower carbonate\\u000a to phosphate content than crystals found in

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

    Microsoft Academic Search

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

    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

  5. 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

  6. 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

  7. Effect of nitrate and nitrite on sulfide production by two thermophilic, sulfate-reducing enrichments from an oil field in the North Sea.

    PubMed

    Kaster, Krista M; Grigoriyan, Alexander; Jenneman, Gary; Jennneman, Gary; Voordouw, Gerrit

    2007-05-01

    Thermophilic sulfate-reducing bacteria (tSRB) can be major contributors to the production of H(2)S (souring) in oil reservoirs. Two tSRB enrichments from a North Sea oil field, NS-tSRB1 and NS-tSRB2, were obtained at 58 degrees C with acetate-propionate-butyrate and with lactate as the electron donor, respectively. Analysis by rDNA sequencing indicated the presence of Thermodesulforhabdus norvegicus in NS-tSRB1 and of Archaeoglobus fulgidus in NS-tSRB2. Nitrate (10 mM) had no effect on H(2)S production by mid-log phase cultures of NS-tSRB1 and NS-tSRB2, whereas nitrite (0.25 mM or higher) inhibited sulfate reduction. NS-tSRB1 did not recover from inhibition, whereas sulfate reduction activity of NS-tSRB2 recovered after 500 h. Nitrite was also effective in souring inhibition and H(2)S removal in upflow bioreactors, whereas nitrate was similarly ineffective. Hence, nitrite may be preferable for souring prevention in some high-temperature oil fields because it reacts directly with sulfide and provides long-lasting inhibition of sulfate reduction. PMID:17245576

  8. 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.

  9. Ubiquity and Diversity of Dissimilatory (Per)chlorate-Reducing Bacteria

    PubMed Central

    Coates, John D.; Michaelidou, Urania; Bruce, Royce A.; O’Connor, Susan M.; Crespi, Jill N.; Achenbach, Laurie A.

    1999-01-01

    Environmental contamination with compounds containing oxyanions of chlorine, such as perchlorate or chlorate [(per)chlorate] or chlorine dioxide, has been a constantly growing problem over the last 100 years. Although the fact that microbes reduce these compounds has been recognized for more than 50 years, only six organisms which can obtain energy for growth by this metabolic process have been described. As part of a study to investigate the diversity and ubiquity of microorganisms involved in the microbial reduction of (per)chlorate, we enumerated the (per)chlorate-reducing bacteria (ClRB) in very diverse environments, including pristine and hydrocarbon-contaminated soils, aquatic sediments, paper mill waste sludges, and farm animal waste lagoons. In all of the environments tested, the acetate-oxidizing ClRB represented a significant population, whose size ranged from 2.31 × 103 to 2.4 × 106 cells per g of sample. In addition, we isolated 13 ClRB from these environments. All of these organisms could grow anaerobically by coupling complete oxidation of acetate to reduction of (per)chlorate. Chloride was the sole end product of this reductive metabolism. All of the isolates could also use oxygen as a sole electron acceptor, and most, but not all, could use nitrate. The alternative electron donors included simple volatile fatty acids, such as propionate, butyrate, or valerate, as well as simple organic acids, such as lactate or pyruvate. Oxidized-minus-reduced difference spectra of washed whole-cell suspensions of the isolates had absorbance maxima close to 425, 525, and 550 nm, which are characteristic of type c cytochromes. In addition, washed cell suspensions of all of the ClRB isolates could dismutate chlorite, an intermediate in the reductive metabolism of (per)chlorate, into chloride and molecular oxygen. Chlorite dismutation was a result of the activity of a single enzyme which in pure form had a specific activity of approximately 1,928 ?mol of chlorite per mg of protein per min. Analyses of the 16S ribosomal DNA sequences of the organisms indicated that they all belonged to the alpha, beta, or gamma subclass of the Proteobacteria. Several were closely related to members of previously described genera that are not recognized for the ability to reduce (per)chlorate, such as the genera Pseudomonas and Azospirllum. However, many were not closely related to any previously described organism and represented new genera within the Proteobacteria. The results of this study significantly increase the limited number of microbial isolates that are known to be capable of dissimilatory (per)chlorate reduction and demonstrate the hitherto unrecognized phylogenetic diversity and ubiquity of the microorganisms that exhibit this type of metabolism. PMID:10583970

  10. Reclassification of the sulfate- and nitrate-reducing bacterium Desulfovibrio vulgaris subsp. oxamicus as Desulfovibrio oxamicus sp. nov., comb. nov.

    PubMed

    López-Cortés, Alejandro; Fardeau, Marie-Laure; Fauque, Guy; Joulian, Catherine; Ollivier, Bernard

    2006-07-01

    Desulfovibrio vulgaris subsp. oxamicus (type strain, DSM 1925(T)) was found to use nitrate as a terminal electron acceptor, the latter being reduced to ammonium. Phylogenetic studies indicated that strain DSM 1925(T) was distantly related to the type strain of Desulfovibrio vulgaris (95.4 % similarity of the small-subunit rRNA gene) and had as its closest phylogenetic relatives two other nitrate- and sulfate-reducing bacteria, namely Desulfovibrio termitidis (99.4 % similarity) and Desulfovibrio longreachensis (98.4 % similarity). Additional experiments were conducted to characterize better strain DSM 1925(T). This strain incompletely oxidized lactate and ethanol to acetate. It also oxidized butanol, pyruvate and citrate, but not glucose, fructose, acetate, propionate, butyrate, methanol, glycerol or peptone. The optimum temperature for growth was 37 degrees C (range 16-50 degrees C) and the optimum NaCl concentration for growth was 0.1 % (range 0-5 %). Because of significant genotypic and phenotypic differences from Desulfovibrio termitidis and Desulfovibrio longreachensis, reclassification of Desulfovibrio vulgaris subsp. oxamicus as Desulfovibrio oxamicus sp. nov., comb. nov., is proposed. The type strain is strain Monticello 2(T) (=DSM 1925(T)=NCIMB 9442(T)=ATCC 33405(T)). PMID:16825618

  11. The Impact of Simulated Sulfate Deposition on Peatland Testate Amoebae

    Microsoft Academic Search

    Richard Payne; Vincent Gauci; Dan J. Charman

    2010-01-01

    Peatlands subjected to sulfate deposition have been shown to produce less methane, believed to be due to competitive exclusion\\u000a of methanogenic archaea by sulfate-reducing bacteria. Here, we address whether sulfate deposition produces impacts on a higher\\u000a microbial group, the testate amoebae. Sodium sulfate was applied to experimental plots on a Scottish peatland and samples\\u000a extracted after a period of more

  12. Citric acid wastewater as electron donor for biological sulfate reduction

    Microsoft Academic Search

    Alfons J. M. Stams; Jacco Huisman; Pedro A. Garcia Encina; Gerard Muyzer

    2009-01-01

    Citrate-containing wastewater is used as electron donor for sulfate reduction in a biological treatment plant for the removal\\u000a of sulfate. The pathway of citrate conversion coupled to sulfate reduction and the microorganisms involved were investigated.\\u000a Citrate was not a direct electron donor for the sulfate-reducing bacteria. Instead, citrate was fermented to mainly acetate\\u000a and formate. These fermentation products served as

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

    SciTech Connect

    Lee Krumholz

    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.

  14. Bacterial communities in haloalkaliphilic sulfate-reducing bioreactors under different electron donors revealed by 16S rRNA MiSeq sequencing.

    PubMed

    Zhou, Jiemin; Zhou, Xuemei; Li, Yuguang; Xing, Jianmin

    2015-09-15

    Biological technology used to treat flue gas is useful to replace conventional treatment, but there is sulfide inhibition. However, no sulfide toxicity effect was observed in haloalkaliphilic bioreactors. The performance of the ethanol-fed bioreactor was better than that of lactate-, glucose-, and formate-fed bioreactor, respectively. To support this result strongly, Illumina MiSeq paired-end sequencing of 16S rRNA gene was applied to investigate the bacterial communities. A total of 389,971 effective sequences were obtained and all of them were assigned to 10,220 operational taxonomic units (OTUs) at a 97% similarity. Bacterial communities in the glucose-fed bioreactor showed the greatest richness and evenness. The highest relative abundance of sulfate-reducing bacteria (SRB) was found in the ethanol-fed bioreactor, which can explain why the performance of the ethanol-fed bioreactor was the best. Different types of SRB, sulfur-oxidizing bacteria, and sulfur-reducing bacteria were detected, indicating that sulfur may be cycled among these microorganisms. Because high-throughput 16S rRNA gene paired-end sequencing has improved resolution of bacterial community analysis, many rare microorganisms were detected, such as Halanaerobium, Halothiobacillus, Desulfonatronum, Syntrophobacter, and Fusibacter. 16S rRNA gene sequencing of these bacteria would provide more functional and phylogenetic information about the bacterial communities. PMID:25897699

  15. Copper tolerance in iron-reducing bacteria: Implications for copper mobilization in sediments

    SciTech Connect

    Markwiese, J.T.; Meyer, J.S.; Colberg, P.J.S. [Univ. of Wyoming, Laramie, WY (United States)

    1998-04-01

    Iron-reducing bacteria enriched from a Cu-contaminated sediment were more tolerant of Cu adsorbed to hydrous ferric oxide (HFO) than were pristine-sediment bacteria. Tolerance was enhanced by increasing the Cu concentration in the culture medium over time, enabling the bacteria to begin reducing Cu-contaminated HFO sooner and at a faster rate than Cu-intolerant bacteria. Copper tolerance confers a greater ability to reduce contaminated HFO and may result in a greater potential for Cu mobilization in sediments.

  16. Effect of sulfide, selenite and mercuric mercury on the growth and methylation capacity of the sulfate reducing bacterium Desulfovibrio desulfuricans.

    PubMed

    Truong, Hoang-Yen T; Chen, Yu-Wei; Belzile, Nelson

    2013-04-01

    Cultures of the sulfate reducing bacteria Desulfovibrio desulfuricans were grown under anoxic conditions to study the effect of added sulfide, selenite and mercuric ions. A chemical trap consisting in a CuSO4 solution was used to control the poisoning effect induced by the bacterial production of hydrogen sulfide via the precipitation of CuS. Following the addition of Hg(2+), the formation of methylmercury (MeHg) was correlated to bacterial proliferation with most of MeHg found in the culture medium. A large fraction (50-80%) of added Hg(2+) to a culture ended up in a solid phase (Hg(0) and likely HgS) limiting its bioavailability to cells with elemental Hg representing ~40% of the solid. Following the addition of selenite, a small fraction was converted into Se(0) inside the cells and, even though the conversion to this selenium species increased with the increase of added selenite, it never reached more than 49% of the added amount. The formation of volatile dimethylselenide is suggested as another detoxification mechanism. In cultures containing both added selenite and mercuric ions, elemental forms of the two compounds were still produced and the increase of selenium in the residual fraction of the culture suggests the formation of mercuric selenite limiting the bioavailability of both elements to cells. PMID:23454698

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

    SciTech Connect

    Ramanand, K.; Suflita, J.M. (Univ. of Oklahoma, Norman (USA))

    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.

  18. Desulfovibrio inopinatus, sp. nov., a new sulfate-reducing bacterium that degrades hydroxyhydroquinone (1,2,4-trihydroxybenzene)

    Microsoft Academic Search

    Wolfram Reichenbecher; Bernhard Schink

    1997-01-01

    A new sulfate-reducing bacterium was isolated from marine sediment with hydroxyhydroquinone (1,2,4-trihydroxybenzene) as\\u000a the sole electron and carbon source. Strain HHQ 20 grew slowly with doubling times of > 20 h and oxidized hydroxyhydroquinone,\\u000a lactate, pyruvate, ethanol, fructose, and ribose incompletely to acetate and carbon dioxide, with concomitant reduction of\\u000a sulfate to sulfide. Cells were large, vibrio-shaped, and gram-negative with

  19. Performance and Ethanol Oxidation Kinetics of a Sulfate-Reducing Fluidized-Bed Reactor Treating Acidic Metal-Containing Wastewater

    Microsoft Academic Search

    Anna H. Kaksonen; Peter D. Franzmann; Jaakko A. Puhakka

    2003-01-01

    The treatment of simulated acidic wastewater (pH 2.5–5)containing sulfate (1.0–2.2 g l-1), zinc (15–340 mg l -1) and iron (57 mg l -1) was studied in a sulfate-reducing fluidized-bed reactor (FBR) at 35 °C.The original lactate feed for enrichment and maintenance\\u000a of the FBRculture was replaced stepwise with ethanol over 50 days. The robustnessof the process was studied by increasing

  20. Desulfacinum subterraneumsp. nov., a New Thermophilic Sulfate-Reducing Bacterium Isolated from a High-Temperature Oil Field

    Microsoft Academic Search

    E. P. Rozanova; T. P. Tourova; T. V. Kolganova; A. M. Lysenko; L. L. Mityushina; S. K. Yusupov; S. S. Belyaev

    2001-01-01

    A new thermophilic sulfate-reducing bacterium isolated from the high-temperature White Tiger oil field (Vietnam) is described. Cells of the bacterium are oval (0.4–0.6 by 0.6–1.8 µm), nonmotile, non-spore-forming, and gram-negative. Growth occurs at 45 to 65°C (with an optimum at 60°C) at NaCl concentrations of 0 to 50 g\\/l. In the course of sulfate reduction, the organism can utilize lactate,

  1. 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...

  2. Genus-specific and phase-dependent effects of nitrate on a sulfate-reducing bacterial community as revealed by dsrB -based DGGE analyses of wastewater reactors

    Microsoft Academic Search

    Kouhei Mizuno; Yui Morishita; Akiko Ando; Naofumi Tsuchiya; Mai Hirata; Kenji Tanaka

    The biogenic production of hydrogen sulfide is a serious problem associated with wastewater treatment. The aim of this study\\u000a was to investigate the inhibitory effect of nitrate on the dynamics of sulfate-reducing bacteria (SRB) community in a laboratory-scale\\u000a wastewater reactor, originating from a denitrifying plant using activated sludge. For this purpose, denaturing gradient gel\\u000a electrophoresis (DGGE) analysis targeting the dsrB

  3. High Motility Reduces Grazing Mortality of Planktonic Bacteria

    PubMed Central

    Matz, Carsten; Jürgens, Klaus

    2005-01-01

    We tested the impact of bacterial swimming speed on the survival of planktonic bacteria in the presence of protozoan grazers. Grazing experiments with three common bacterivorous nanoflagellates revealed low clearance rates for highly motile bacteria. High-resolution video microscopy demonstrated that the number of predator-prey contacts increased with bacterial swimming speed, but ingestion rates dropped at speeds of >25 ?m s?1 as a result of handling problems with highly motile cells. Comparative studies of a moderately motile strain (<25 ?m s?1) and a highly motile strain (>45 ?m s?1) further revealed changes in the bacterial swimming speed distribution due to speed-selective flagellate grazing. Better long-term survival of the highly motile strain was indicated by fourfold-higher bacterial numbers in the presence of grazing compared to the moderately motile strain. Putative constraints of maintaining high swimming speeds were tested at high growth rates and under starvation with the following results: (i) for two out of three strains increased growth rate resulted in larger and slower bacterial cells, and (ii) starved cells became smaller but maintained their swimming speeds. Combined data sets for bacterial swimming speed and cell size revealed highest grazing losses for moderately motile bacteria with a cell size between 0.2 and 0.4 ?m3. Grazing mortality was lowest for cells of >0.5 ?m3 and small, highly motile bacteria. Survival efficiencies of >95% for the ultramicrobacterial isolate CP-1 (?0.1 ?m3, >50 ?m s?1) illustrated the combined protective action of small cell size and high motility. Our findings suggest that motility has an important adaptive function in the survival of planktonic bacteria during protozoan grazing. PMID:15691949

  4. 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.

  5. Biodegradation of munitions compounds by a sulfate reducing bacterial enrichment culture

    SciTech Connect

    Boopathy, R.; Manning, J. [Argonne National Lab., IL (United States). Environmental Research Div.

    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.

  6. Anaerobic biodegradation of long-chain n-alkanes under sulfate-reducing conditions

    SciTech Connect

    Caldwell, M.E.; Suflita, J.M. [Univ. of Oklahoma, Norman, OK (United States). Dept. of Botany and Microbiology] [Univ. of Oklahoma, Norman, OK (United States). Dept. of Botany and Microbiology; Garrett, R.M.; Prince, R.C. [Exxon Research and Engineering Co., Annandale, NJ (United States)] [Exxon Research and Engineering Co., Annandale, NJ (United States)

    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.

  7. 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.

  8. Resistance to Copper of some Oxidizing and Reducing Bacteria

    Microsoft Academic Search

    G. H. Booth; Stella J. Mercer

    1963-01-01

    CERTAIN types of bacteria, particularly Thiobacillus thiooxidans and Ferrobacillus ferrooxidans, are known to assist the oxidation of pyritic ores1-4. It has also been shown5,6 that the rate of natural leaching of uranium from low-grade ores can be significantly increased when the leaching is done in the presence of pyrite that is itself undergoing microbiological oxidation. It is possible that a

  9. Ultrasound as a method for reducing bacteria on poultry

    E-print Network

    Feria, Rebeca

    1989-01-01

    suspensions of 10 strains of bacteria were placed in thin test tubes, exposed to ultrasonic waves, and divided into 3 groups according to their susceptibility to the ultrasonic waves. The first group, which was represented by Bacillus anthracis... crystal to generate sound waves with a frequency of approximately 400, 000 Hz. Suspenstons of Bacillus fisheri were irradiated in a sea water solution inside a round bottom tube and'. with great agitation so as to prevent the formation of stat, ionary...

  10. Sulfate reduction, nutrient limitation, and reactor design considerations in anaerobic digesters

    Microsoft Academic Search

    1991-01-01

    Three areas of improvement in anaerobic digestion were investigated: inhibition of sulfate reduction, nutrient limitation, and reactor design. In the anaerobic treatment of wastewaters containing high concentrations of sulfate, hydrogen sulfide, an undesirable end product, is produced by sulfate reducing bacteria (SRB). Research was conducted to evaluate the feasibility of adding SRB-specific biochemical inhibitors to a waste stream as a

  11. Effects of intestinal bacteria-derived p-cresyl sulfate on Th1-type immune response in vivo and in vitro

    SciTech Connect

    Shiba, Takahiro, E-mail: takahiro-shiba@yakult.co.jp; 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-? was suppressed by pCS. Further, pCS decreased the percentage of IFN-?-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-? was suppressed by p-cresyl sulfate. • p-Cresyl sulfate decreased the percentage of IFN-?-producing Th1 cells in vitro.

  12. Defective proteoglycan sulfation of the growth plate zones causes reduced chondrocyte proliferation via an altered Indian hedgehog signalling.

    PubMed

    Gualeni, Benedetta; Facchini, Marcella; De Leonardis, Fabio; Tenni, Ruggero; Cetta, Giuseppe; Viola, Manuela; Passi, Alberto; Superti-Furga, Andrea; Forlino, Antonella; Rossi, Antonio

    2010-07-01

    Mutations in the sulfate transporter gene, SCL26A2, lead to cartilage proteoglycan undersulfation resulting in chondrodysplasia in humans; the phenotype is mirrored in the diastrophic dysplasia (dtd) mouse. It remains unclear whether bone shortening and deformities are caused solely by changes in the cartilage matrix, or whether chondroitin sulfate proteoglycan undersulfation affects also signalling pathways involved in cell proliferation and differentiation. Therefore we studied macromolecular sulfation in the different zones of the dtd mouse growth plate and these data were related to growth plate histomorphometry and proliferation analysis. A 2-fold increase of non-sulfated disaccharide in dtd animals compared to wild-type littermates in the resting, proliferative and hypertrophic zones was detected indicating proteoglycan undersulfation; among the three zones the highest level of undersulfation was in the resting zone. The relative height of the hypertrophic zone and the average number of cells per column in the proliferative and hypertrophic zones were significantly reduced compared to wild-types; however the total height of the growth plate was within normal values. The chondrocyte proliferation rate, measured by bromodeoxyuridine labelling, was also significantly reduced in mutant mice. Immunohistochemistry combined with expression data of the dtd growth plate demonstrated that the sulfation defect alters the distribution pattern, but not expression, of Indian hedgehog, a long range morphogen required for chondrocyte proliferation and differentiation. These data suggest that in dtd mice proteoglycan undersulfation causes reduced chondrocyte proliferation in the proliferative zone via the Indian hedgehog pathway, therefore contributing to reduced long bone growth. PMID:20470884

  13. A Marine Sulfate-Reducing Bacterium Producing Multiple Antibiotics: Biological and Chemical Investigation

    PubMed Central

    Zhang, Yi; Mu, Jun; Gu, Xiaojie; Zhao, Chenyan; Wang, Xiaoliang; Xie, Zeping

    2009-01-01

    A marine sulfate-reducing bacterium SRB-22 was isolated by means of the agar shake dilution method and identified as Desulfovibrio desulfuricans by morphological, physiological and biochemical characteristics and 16S rDNA analysis. In the bioassay, its extract showed broad-spectrum antimicrobial activity using the paper disc agar diffusion method. This isolate showed a different antimicrobial profile than either ampicillin or nystatin and was found to produce at least eight antimicrobial components by bioautography. Suitable fermentation conditions for production of the active constituents were determined to be 28 day cultivation at 25 °C to 30 °C with a 10% inoculation ratio. Under these conditions, the SRB-22 was fermented, extracted and chemically investigated. So far an antimicrobial compound, mono-n-butyl phthalate, and an inactive compound, thymine, have been isolated and characterized. PMID:19841718

  14. A marine sulfate-reducing bacterium producing multiple antibiotics: biological and chemical investigation.

    PubMed

    Zhang, Yi; Mu, Jun; Gu, Xiaojie; Zhao, Chenyan; Wang, Xiaoliang; Xie, Zeping

    2009-01-01

    A marine sulfate-reducing bacterium SRB-22 was isolated by means of the agar shake dilution method and identified as Desulfovibrio desulfuricans by morphological, physiological and biochemical characteristics and 16S rDNA analysis. In the bioassay, its extract showed broad-spectrum antimicrobial activity using the paper disc agar diffusion method. This isolate showed a different antimicrobial profile than either ampicillin or nystatin and was found to produce at least eight antimicrobial components by bioautography. Suitable fermentation conditions for production of the active constituents were determined to be 28 day cultivation at 25 degrees C to 30 degrees C with a 10% inoculation ratio. Under these conditions, the SRB-22 was fermented, extracted and chemically investigated. So far an antimicrobial compound, mono-n-butyl phthalate, and an inactive compound, thymine, have been isolated and characterized. PMID:19841718

  15. 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.

  16. D-Area Sulfate Reduction Study Bacteria Population and Organic Selection Laboratory Testing

    SciTech Connect

    Phifer, M.A.

    2002-12-11

    An acidic/metals/sulfate groundwater contaminant plume emanates from a 12.5-acre sedimentation basin, due to the contaminated runoff the basin receives from an adjacent 8.9-acre coal pile. The most geochemically important metals present in the plume include iron and aluminum. Additionally elevated concentrations of beryllium, cadmium, chromium, copper, mercury, nickel, and zinc are also present. The plume is located within a 50-foot thick water table aquifer, which consists of a series of interbedded sand, silt, and clay layers with saturated hydraulic conductivities ranging from 1E-3 to 1E-7 cm/s. The free surface of the water table ranges from at grade to 15 feet below grade. The soils in the upper portion of the aquifer are generally at the lower end of the hydraulic conductivity range, whereas the soils in the lower portion generally contain more sand and are at the higher end of the hydraulic conductivity range. Higher contaminant concentrations are generally present in the upper portion of the aquifer.

  17. Ultrasound as a method for reducing bacteria on poultry 

    E-print Network

    Feria, Rebeca

    1989-01-01

    of storage even with the most effective of treatments of IX lactic acid. It can be hypothesized that a low pH increases the lag phase by 37 1nhib1ting the growth of lar ge numbers of bacteria or by sublethally stressing them so that they recover only... after a long lag period. As was reported by Mulder et al. (1987), the lactic acid lingers on the surface of the drumst ick so as to decrease the pH of the skin and inhibit the growth of gram negative microflora. If the lactic acid treatments elicit...

  18. Multiple non-reducing chain termini isolated from bovine corneal keratan sulfates.

    PubMed

    Tai, G H; Huckerby, T N; Nieduszynski, I A

    1996-09-20

    Keratan sulfate-containing proteoglycans were isolated from bovine cornea (15-month-old to 3-year-old animals) and digested with the enzyme, keratanase II. The released oligosaccharides, which included non-reducing termini and repeat region oligosaccharides but not linkage regions, were reduced with alkaline borohydride and fractionated on a Spherisorb column. These oligosaccharides were examined by 600-MHz 1H NMR spectroscopy using one- and two-dimensional methods and, in addition to some oligosaccharide alditols previously recovered from skeletal keratan sulfate, the following new capping structures were identified: NeuAcalpha2-6Galbeta1-4GlcNAc(S)-ol, NeuAcalpha2-3Gal(S)beta1-4GlcNAc(S)beta1-3Galbeta1-4GlcNAc(S )-ol, NeuGcalpha2-6Galbeta1-4GlcNAc(S)beta1-3Galbeta1-4Gl cNA c(S)-ol, NeuGcalpha2-3Galbeta1-4GlcNAc(S)beta1-3Galbeta1-4Gl cNA c(S)-ol, NeuGcalpha2-3Gal(S)beta1-4GlcNAc(S)beta1-3Galbeta1-4GlcNAc(S )-ol, NeuGcalpha2-3Gal(S)beta1-4GlcNAc(S)beta1-3Gal(S)beta1-4GlcNAc(S)-o l, Galalpha1-3Galbeta1-4GlcNAc(S)beta1-3Galbeta1-4GlcNAc( S)-ol, Galalpha1-3Galbeta1-4GlcNAc(S)beta1-3Gal(S)beta1-4GlcNAc(S)- ol, GlcNAc(S)beta1-3Gal(S)beta1-4GlcNAc(S)-ol, and GalNAc(S)beta1-3Gal(S)beta1-4GlcNAc(S)-ol. These structures represent seven families of capping residues, whose relative molar proportions are given in parentheses: NeuAcalpha(2-3)- (12%), NeuAcalpha(2-6)- (41%), NeuGcalpha(2-3)- and NeuGcalpha(2-6)- families (12%), Galalpha(1-3)- (26%), GalNAc(S)beta(1-3)- (5%), and GlcNAc(S)beta(1-3)- (4%). It is not clear, at present, where each of these structures occurs on the bi-antennary N-linked corneal keratan sulfate chains, which themselves occur within three keratan sulfate proteoglycan species. However, examination of the relative proportions of the capping to the repeat structures and knowledge of the average molecular size suggests that the sum of these non-reducing termini represents the caps of two antennae. PMID:8798563

  19. Mercury methylation by sulphate-reducing bacteria from sediments of an acid stressed lake

    Microsoft Academic Search

    Alison Kerry; Pamela M. Welbourn; Betsy Prucha; Greg Miede

    1991-01-01

    The role of freshwater sulphate-reducing bacteria in McHg production was examined by adding specific microbial inhibitors\\u000a to anoxic lake sediments spiked with 203HgCl2 and measuring net methylation. The effect of increased sulphate (such as would arise from acid deposition in the area) on\\u000a the activity of sulphate-reducing bacteria both in terms of sulphate reduction rate and methylation of Hg was

  20. Function of Periplasmic Hydrogenases in the Sulfate-Reducing Bacterium Desulfovibrio vulgaris Hildenborough? †

    PubMed Central

    Caffrey, Sean M.; Park, Hyung-Soo; Voordouw, Johanna K.; He, Zhili; Zhou, Jizhong; Voordouw, Gerrit

    2007-01-01

    The sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough possesses four periplasmic hydrogenases to facilitate the oxidation 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 their cellular functions, we have compared the growth rates of existing (hyd and hyn1) and newly constructed (hys and hyn-1 hyd) mutants to those of the wild type in defined media in which lactate or hydrogen at either 5 or 50% (vol/vol) was used as the sole electron donor for sulfate reduction. Only strains missing the [Fe] hydrogenase were significantly affected during growth with lactate or with 50% (vol/vol) hydrogen as the sole electron donor. When the cells were grown at low (5% [vol/vol]) hydrogen concentrations, those missing the [NiFeSe] hydrogenase suffered the greatest impairment. The growth rate data correlated strongly with gene expression results obtained from microarray hybridizations and real-time PCR using mRNA extracted from cells grown under the three conditions. Expression of the hys genes followed the order 5% hydrogen > 50% hydrogen > lactate, whereas expression of the hyd genes followed the reverse order. These results suggest that growth with lactate and 50% hydrogen is associated with high intracellular hydrogen concentrations, which are best captured by the higher activity, lower affinity [Fe] hydrogenase. In contrast, growth with 5% hydrogen is associated with a low intracellular hydrogen concentration, requiring the lower activity, higher affinity [NiFeSe] hydrogenase. PMID:17601789

  1. 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)).

  2. Effects of metal additions on sulfate reduction activity in wastewaters

    Microsoft Academic Search

    Oliver J. Hao; Li Huang; Jin M. Chen; Robert L. Buglass

    1994-01-01

    Sulfate reducing bacteria (SRB) convert sulfate to sulfide resulting in the odor and corrosion prohlems in sewers. Evaluation of metal toxicity on SRB was conducted in three phase: screening tests in test tubes, batch tests of wastewater with enriched SRB culture, and serum bottle tests with raw wastewater. The inhibitory metal concentrations towards SRB in test tubes were relatively high,

  3. Effects of temperature on anaerobic decomposition of high-molecular weight organic matter under sulfate-reducing conditions

    NASA Astrophysics Data System (ADS)

    Matsui, Takato; Kojima, Hisaya; Fukui, Manabu

    2013-03-01

    Most sedimentary mineralization occurs along coasts under anaerobic conditions. In the absence of oxygen, high-molecular weight organic matter in marine sediments is gradually decomposed by hydrolysis, fermentation and sulfate reduction. Because of the different responses of the respective steps to temperature, degradation may be specifically slowed or stopped in certain step. To evaluate the effect of temperature on cellobiose degradation, culture experiments were performed at six different temperatures (3 °C, 8 °C, 13 °C, 18 °C, 23 °C, and 28 °C) under sulfate-reducing conditions. This study measured the concentrations of sulfide, dissolved organic carbon (DOC), and organic acids during that degradation. Degradation patterns were divided into three temperature groups: 3 °C, 8/13 °C, and 18/23/28 °C. The decrease in DOC proceeded in two steps, except at 3 °C. The length of the stagnant phase separating these two steps differed greatly between temperatures of 8/13 °C and 18/23/28 °C. In the first step, organic carbon was consumed by hydrolysis, fermentation and sulfate reduction. In the second step, acetate accumulated during the first step was oxidized by sulfate reduction. Bacterial communities in the cultures were analyzed by denaturing gradient gel electrophoresis (DGGE); the major differences among the three temperature groups were attributed to shifts in acetate-using sulfate reducers of the genus Desulfobacter. This suggests that temperature characteristics of dominant acetate oxidizers are important factors in determining the response of carbon flow in coastal marine sediments in relation to the changes in temperature.

  4. Bidirectional sulfate diffusion in saline-lake sediments: evidence from Devils Lake, northeast North Dakota

    USGS Publications Warehouse

    Komor, S.C.

    1992-01-01

    Chemical and isotopic gradients in pore water in Devils Lake indicate that maximum rates of sulfate reduction occur between 1 and 3 cm depth in the bottom sediments. The abundance of electron acceptors enables sulfate-reducing bacteria to outcompete methanogenic bacteria for organic material and thereby suppress methane production. Suppression of methanogenesis may be widespread in sulfate-rich lakes and wetlands and may limit methane fluxes from these water bodies to the atmostphere. -from Author

  5. Accelerated biotransformation of carbon tetrachloride and chloroform by sulfate-reducing enrichment cultures

    SciTech Connect

    Freedman, D.L.; Hashsham, S. [Univ. of Illinois, Urbana, IL (United States). Dept. of Civil Engineering; Lasecki, M. [HDR Engineering Inc., Lake Oswego, OR (United States); Scholze, R. [Army Corps of Engineers, Champaign, IL (United States). Construction Engineering Research Labs.

    1995-12-31

    The biotransformation of carbon tetrachloride (CT) and chloroform (CF) was examined with lactate- and acetate-grown sulfate-reducing enrichment cultures. Both cultures transformed CT, with approximately 50% reductively dechlorinated to CF and up to 10% to dichloromethane (DCM). Addition of cyanocobalamin increased the rate of CT transformation more than 100-fold. The principal product from [{sup 14}C]CT with cyanocobalamin added was carbon disulfide (CS{sub 2}); less than 3% was reduced to CF plus DCM. Autoclaved cultures that received cyanocobalamin were only one third as fast as their live counterparts, but produced similar amounts of CS{sub 2}. With CF, addition of cyanocobalamin to acetate- and lactate-grown cultures also increased the rate of transformation more than 100-fold. DCM was the principal transformation product until CF additions reached 270 mg/L, at which point almost no increase in DCM was observed. Thus, low levels of cyanocobalamin substantially accelerated the rate of CT and CF transformation and altered the distribution of products formed.

  6. Desulfocarbo indianensis gen. nov., sp. nov., a benzoate-oxidizing, sulfate-reducing bacterium isolated from water extracted from a coal bed.

    PubMed

    An, Thuy T; Picardal, Flynn W

    2014-08-01

    A novel, strictly anaerobic, sulfate-reducing bacterium, designated strain SCBM(T), was isolated from water extracted from a coal bed in Indiana, USA. The isolate was characterized by a polyphasic taxonomic approach that included phenotypic and genotypic characterizations. Cells of strain SCBM(T) were vibrio-shaped, polarly flagellated, Gram-negative, motile, oxidase-negative and weakly catalase-positive. Growth of strain SCBM(T) was observed at NaCl concentrations ranging from 0 to 300 mM. However, no growth was observed when 1 M or more NaCl was present. Growth was observed at 16-37 °C, with optimal growth at 30 °C. The optimum pH for growth was 7, although growth was observed from pH 6.5 to 8. The doubling time under optimal growth conditions (30 °C, pH 7, 2.5 mM benzoate, 14 mM sulfate) was 2.7 days. Bicarbonate, HEPES, PIPES and MES were effective buffers for growth of strain SCBM(T), but citrate inhibited growth. When sulfate was provided as the electron acceptor, strain SCBM(T) grew autotrophically with hydrogen as the electron donor and heterotrophically on benzoate, formate, acetate, pyruvate, butyrate, fumarate, succinate and palmitate. None of the substrates tested supported fermentative growth. Thiosulfate and sulfate were used as electron acceptors coupled to benzoate oxidation, but sulfite, elemental sulfur, DMSO, anthraquinone 2,6-disulfonate, nitrate, nitrite, ferric citrate, hydrous iron oxide and oxygen were not. The G+C content of genomic DNA was 62.5?mol%. The major cellular fatty acids were anteiso-C(15?:?0) and C(18?:?1)?7c. Phylogenetic analysis based on 16S rRNA gene sequencing placed strain SCBM(T) into a distinct lineage within the class Deltaproteobacteria. The closest, cultivated phylogenetic relative of strain SCBM(T) was Desulfarculus baarsii DSM 2075(T), with only 91.7% 16S rRNA gene sequence identity. On the basis of phenotypic and genotypic analyses, strain SCBM(T) represents a novel genus and species of sulfate-reducing bacteria, for which the name Desulfocarbo indianensis gen. nov., sp. nov. is proposed. The type strain of Desulfocarbo indianensis is SCBM(T) (?=?DSM 28127(T)?=?JCM 19826(T)). Desulfocarbo is the second genus of the order Desulfarculales. PMID:24876241

  7. 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

  8. Desulfovibrio legallis sp. nov.: A Moderately Halophilic, Sulfate-Reducing Bacterium Isolated from a Wastewater Digestor in Tunisia

    Microsoft Academic Search

    Olfa Ben Dhia Thabet; Terres Wafa; Khelifi Eltaief; Jean-Luc Cayol; Moktar Hamdi; Guy Fauque; Marie-Laure Fardeau

    2011-01-01

    A new moderately halophilic sulfate-reducing bacterium (strain H1T) was enriched and isolated from a wastewater digestor in Tunisia. Cells were curved, motile rods (2–3 x 0.5 ?m). Strain H1T grew at temperatures between 22 and 43°C (optimum 35°C), and at pH between 5.0 and 9.2 (optimum 7.3–7.5). Strain H1T required salt for growth (1–45 g of NaCl\\/l), with an optimum at 20–30 g\\/l. Sulfate, sulfite,

  9. 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...

  10. Interactions of microbes in aquatic systems Uncultured populations of bacteria were analyzed in aquatic systems and populations related

    E-print Network

    Upchurch, Gary - Department of Biology, Texas State University

    Interactions of microbes in aquatic systems Uncultured populations of bacteria and quantitative analysis of Archaea in anaerobic sediments of Lake Rotsee (Lucerne of aggregate-forming phototrophic sulfur and sulfate-reducing bacteria in the chemocline

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

    Microsoft Academic Search

    Scholten; Johannes

    2006-01-01

    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

  12. Lead removal and toxicity reduction from industrial wastewater through biological sulfate reduction process

    Microsoft Academic Search

    Paphungkorn Teekayuttasakul; Ajit P. Annachhatre

    2008-01-01

    The practicability of lead removal from sulfate-rich wastewater through biological sulfate reduction process with hydrogen as electron donor was investigated. Sulfide, which was converted from sulfate by a sulfate-reducing bacteria (SRB) in a gas-lift reactor, was used to remove lead as lead sulfide precipitate. Furthermore, the toxicity of wastewater in terms of whole effluent toxicity (WET) before and after treatment

  13. Sulfate Reduction at pH 4.0 for Treatment of Process and Wastewaters

    Microsoft Academic Search

    Martijn F. M. Bijmans; Erik de Vries; Chun-Hui Yang; Cees J. N. Buisman; Piet N. L. Lens; Mark Dopson

    2010-01-01

    Acidic industrial process and wastewaters often contain high sulfate and metal concentrations and their direct biological treatment is thus far not possible as biological processes at pH < 5 have been neglected. Sulfate-reducing bacteria convert sulfate to sulfide that can subsequently be used to recover metals as metal-sulfides precipitate. This study reports on high-rate sulfate reduction with a mixed microbial

  14. Role of Carbon Dioxide and Acetate in Biosynthesis by Sulphate-reducing Bacteria

    Microsoft Academic Search

    Yu. I. Sorokin

    1966-01-01

    SULPHATE reduction by bacteria is one of the most important biogeochemical processes for which microorganisms are responsible. Sulphate-reducing bacteria obtain energy for biosynthesis from the very small amount released in the reduction of SO4-ions with the participation of easily activated hydrogen of certain organic compounds and with hydrogen gas. Previous work1,2 and my recent experiments have shown that the principal

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

    PubMed

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

    1993-05-01

    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. PMID:7686000

  16. Linkage between community diversity of sulfate-reducing microorganisms and methylmercury concentration in paddy soil.

    PubMed

    Liu, Yu-Rong; Zheng, Yuan-Ming; Zhang, Li-Mei; He, Ji-Zheng

    2014-01-01

    Sulfate-reducing microorganisms (SRM) have been thought to play a key role in mercury (Hg) methylation in anoxic environments. The current study examined the linkage between SRM abundance and diversity and contents of methylmercury (MeHg) in paddy soils collected from a historical Hg mining area in China. Soil profile samples were collected from four sites over a distance gradient downstream the Hg mining operation. Results showed that MeHg content in the soil of each site significantly decreased with the extending distance away from Hg mine. Soil MeHg content was correlated positively with abundance of SRM and the contents of organic matter (OM), NH4(+), SO4(2-), and Hg. The abundances of SRM based on dissimilatory (bi) sulfite reductase (dsrAB) gene at 0-40 cm depths were higher than those at 40-80 cm depth at all sites. The SRM community composition varied in the soils of different sampling sites following terminal restriction fragment length polymorphism (T-RFLP) and phylogenetic analyses, which appeared to be correlated with contents of MeHg, OM, NH4(+), and SO4(2-) through canonical correspondence analysis. The dominant groups of SRM in the soils examined belonged to Deltaproteobacteria and some unknown SRM clusters that could have potential for Hg methylation. These results advance our understanding of the relationship between SRM and methylmercury concentration in paddy soil. PMID:23900947

  17. 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

  18. Electronic Detection of Bacteria Using Holey Reduced Graphene Oxide

    PubMed Central

    2015-01-01

    Carbon nanomaterials have been widely explored for diverse biosensing applications including bacterial detection. However, covalent functionalization of these materials can lead to the destruction of attractive electronic properties. To this end, we utilized a new graphene derivative, holey reduced graphene oxide (hRGO), functionalized with Magainin I to produce a broad-spectrum bacterial probe. Unlike related carbon nanomaterials, hRGO retains the necessary electronic properties while providing the high percentage of available oxygen moieties required for effective covalent functionalization. PMID:24581028

  19. Effect of sulphate-reducing bacteria on electro-chemical corrosion behavior of 16Mn steel in sea mud

    NASA Astrophysics Data System (ADS)

    Zhang, Jing-Lei; Hou, Bao-Rong; Guo, Gong-Yu; Sun, Hu-Yuan; Xu, Yan

    2001-03-01

    The effect of sulfate-reducing bacteria (SRB) on electrochemical corrosion behavior of 16Mn steel, and galvanic corrosion behavior of the steels in the juncture area between bacterial and bacteria-free sea mud was studied in laboratory under simulated conditions. Sea mud dense with SRB was taken from the Qingdao beach. Part of the sea mud was sterilized and the rest was kept in the original condition. The sterilized and original sea mud was put respectively into two plastic testing troughs electrically-connected by an agar potassium chloride salt bridge. Galvanic and non-galvanic 16Mn steel samples were put into the trough at the same intervals. The SRB number measured by the MPN tri-tube method was about 2.4×105 per 100 g mud and was kept basically the same during the experimental period. The p, pH, eH, T, S (salinity) were measured simultaneously. The galvanic current was measured with zero-resistance galvanometer and the corrosion rate was measured with the weight loss method. The results showed that (1) the corrosion rate of 16Mn steel in bacterial sea mud was 4.0 times that in bacteria-free sea mud; (2) galvanic corrosion occurs between steel samples buried in different (bacterial and bacteriafree) sea mud. The steel sample in the bacterial sea mud was the anode of a galvanic couple and had higher corrosion rate than that of the non-galvanic sample. The existence of the galvanic couple increased the corrosion rate of the sample in bacterial sea mud by 4.1%.

  20. 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

  1. Anaerobic biodegradation of nonylphenol in river sediment under nitrate- or sulfate-reducing conditions and associated bacterial community.

    PubMed

    Wang, Zhao; Yang, Yuyin; Dai, Yu; Xie, Shuguang

    2015-04-01

    Nonylphenol (NP) is a commonly detected pollutant in aquatic ecosystem and can be harmful to aquatic organisms. Anaerobic degradation is of great importance for the clean-up of NP in sediment. However, information on anaerobic NP biodegradation in the environment is still very limited. The present study investigated the shift in bacterial community structure associated with NP degradation in river sediment microcosms under nitrate- or sulfate-reducing conditions. Nearly 80% of NP (100 mg kg(-1)) could be removed under these two anaerobic conditions after 90 or 110 days' incubation. Illumina MiSeq sequencing analysis indicated that Proteobacteria, Firmicutes, Bacteroidetes and Chloroflexi became the dominant phylum groups with NP biodegradation. The proportion of Gammaproteobacteria, Deltaproteobacteria and Choloroflexi showed a marked increase in nitrate-reducing microcosm, while Gammaproteobacteria and Firmicutes in sulfate-reducing microcosm. Moreover, sediment bacterial diversity changed with NP biodegradation, which was dependent on type of electron acceptor. PMID:25590825

  2. Method for reducing sulfate formation during regeneration of hot-gas desulfurization sorbents

    DOEpatents

    Bissett, Larry A. (Morgantown, WV); Strickland, Larry D. (Morgantown, WV); Rockey, John M. (Westover, WV)

    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.

  3. 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 ...

  4. COMPARISON OF HYDROGEN CONCENTRATIONS IN PCE-DEHALOGENATING AND SULFATE-REDUCING ESTUARINE SEDIMENTS

    EPA Science Inventory

    The primary transformation pathway for PCE in anoxic environments is through sequential reductive dehalogenation, and information concerning dehalogenation processes that occur in environments containing alternative electron acceptors (sulfate) is limited. Hydrogen is postulated ...

  5. 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...

  6. 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 ...

  7. The Role of Dissolved Organic Matter in Environmental Mercury Methylation by Sulfate Reducing Bacteria

    Microsoft Academic Search

    J. W. Moreau; E. E. Roden; C. Gerbig; C. S. Kim; G. R. Aiken; J. F. Dewild; D. P. Krabbenhoft

    2007-01-01

    Methylmercury (MeHg) production in the environment is controlled by many factors, including biogeochemical controls on mercury bioavailability. Strong focus has been placed on the role of sulfide concentration in determining mercury speciation and cellular uptake. However, in natural waters, dissolved organic matter (DOM) is both ubiquitous and important in influencing mercury speciation and bioavailability. We revisit this issue with experimental

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

    Microsoft Academic Search

    C. Lin; R. Kampalath; J. Jay

    2007-01-01

    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

  9. Neem extract as an inhibitor for biocorrosion influenced by sulfate reducing bacteria: A preliminary investigation

    E-print Network

    , Brajendra Mishra a , David L. Olson a , Anthony E. Kakpovbia c a Department of Metallurgical and Materials 31311, Saudi Arabia a r t i c l e i n f o Article history: Received 19 June 2013 Received in revised

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

    Microsoft Academic Search

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

    2003-01-01

    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,

  11. Competition for hydrogen between acetogenic bacteria and methanogenic archaea

    E-print Network

    Paris-Sud XI, Université de

    Competition for hydrogen between acetogenic bacteria and methanogenic archaea B Morvan, G Fonty bacterial groups: the methanogenic archaea, the sulfate- reducing bacteria and the acetogenic bacteria at 39°C. Fourty-eight-hour-old cultures were used to inoculated AC-11 medium with a similar number

  12. Influence of sulfate-reducing bacteria and thiogenic bacteria on corrosion of carbon steel in refinery recirculating water systems

    SciTech Connect

    Teslya, B.M.; Chupareva, I.E.; Burlov, V.V.

    1987-07-01

    The influence of SRB and TB on the kinetics of carbon steel corrosion was investigated in recirculating water at the Kirishi refinery and in cumulative cultures of the SRB and TB obtained by inoculating elective nutrient media with the recirculating water (300 ml of water per 1000 ml of medium). The concentrations of SRB and TB in the recirculating water and in the cumulative cultures were determined by the serial dilution method. The corrosion activity of the microorganisms was evaluated on the basis of carbon steel specimen corrosion rates under dynamic and static conditions.

  13. Subendothelial retention of lipoprotein (a). Evidence that reduced heparan sulfate promotes lipoprotein binding to subendothelial matrix.

    PubMed Central

    Pillarisetti, S; Paka, L; Obunike, J C; Berglund, L; Goldberg, I J

    1997-01-01

    Vessel wall subendothelial extracellular matrix, a dense mesh formed of collagens, fibronectin, laminin, and proteoglycans, has important roles in lipid and lipoprotein retention and cell adhesion. In atherosclerosis, vessel wall heparan sulfate proteoglycans (HSPG) are decreased and we therefore tested whether selective loss of HSPG affects lipoprotein retention. A matrix synthesized by aortic endothelial cells and a commercially available matrix (Matrigel; , Rutherford, NJ) were used. Treatment of matrix with heparinase/heparitinase (1 U/ml each) increased LDL binding by approximately 1.5-fold. Binding of lipoprotein (a) [Lp(a)] to both subendothelial matrix and Matrigel(R) increased 2-10-fold when the HSPG were removed by heparinase treatment. Incubation of endothelial cells with oxidized LDL (OxLDL) or lysolecithin resulted in decreased matrix proteoglycans and increased Lp(a) retention by matrix. The effect of OxLDL or lysolecithin on endothelial PG was abolished in the presence of HDL. The decrease in matrix HSPG was associated with production of a heparanase-like activity by OxLDL-stimulated endothelial cells. To test whether removal of HSPG exposes fibronectin, a candidate Lp(a) binding protein in the matrix, antifibronectin antibodies were used. The increased Lp(a) binding after HSPG removal was inhibited 60% by antifibronectin antibodies. Similarly, the increased Lp(a) binding to matrix from OxLDL-treated endothelial cells was inhibited by antifibronectin antibodies. We hypothesize that atherogenic lipoproteins stimulate endothelial cell production of heparanase. This enzyme reduces HSPG which in turn promotes Lp(a) retention. PMID:9259586

  14. 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 ?m 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

  15. 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.

  16. Sulfate-Reducing Bacterium Desulfovibrio desulfuricans ND132 as a Model for Understanding Bacterial Mercury Methylation?†

    PubMed Central

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

    2011-01-01

    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

  17. 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

  18. A New Type of Metal-Binding Site in Cobalt- And Zinc-Containing Adenylate Kinases Isolated From Sulfate-Reducers D. Gigas And D. Desulfuricans ATCC 27774

    SciTech Connect

    Gavel, O.Y.; Bursakov, S.A.; Rocco, G.Di; Trincao, J.; Pickering, I.J.; George, G.N.; Calvete, J.J.; Brondino, C.; Pereira, A.S.; Lampreia, J.; Tavares, P.; Moura, J.J.G.; Moura, I.

    2009-05-18

    Adenylate kinase (AK) mediates the reversible transfer of phosphate groups between the adenylate nucleotides and contributes to the maintenance of their constant cellular level, necessary for energy metabolism and nucleic acid synthesis. The AK were purified from crude extracts of two sulfate-reducing bacteria (SRB), Desulfovibrio (D.) gigas NCIB 9332 and Desulfovibrio desulfuricans ATCC 27774, and biochemically and spectroscopically characterized in the native and fully cobalt- or zinc-substituted forms. These are the first reported adenylate kinases that bind either zinc or cobalt and are related to the subgroup of metal-containing AK found, in most cases, in Gram-positive bacteria. The electronic absorption spectrum is consistent with tetrahedral coordinated cobalt, predominantly via sulfur ligands, and is supported by EPR. The involvement of three cysteines in cobalt or zinc coordination was confirmed by chemical methods. Extended X-ray absorption fine structure (EXAFS) indicate that cobalt or zinc are bound by three cysteine residues and one histidine in the metal-binding site of the 'LID' domain. The sequence {sup 129}Cys-X{sub 5}-His-X{sub 15}-Cys-X{sub 2}-Cys of the AK from D. gigas is involved in metal coordination and represents a new type of binding motif that differs from other known zinc-binding sites of AK. Cobalt and zinc play a structural role in stabilizing the LID domain.

  19. 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...

  20. Comparison of reduced volume versus four liters sulfate-free electrolyte lavage solutions for colonoscopy colon cleansing

    Microsoft Academic Search

    Jack A. DiPalma; Bruce G. Wolff; Alan Meagher; Mark v B. Cleveland

    2003-01-01

    OBJECTIVE:In an attempt to improve patient tolerance for colonoscopy cleansing, a reduced volume lavage regimen with 2 L sulfate-free electrolyte lavage solution (SF-ELS, NuLYTELY, Braintree Laboratories, Braintree, MA) plus 20 mg p.o. bisacodyl (Half Lytely, Braintree Laboratories) was compared with standard 4 L SF-ELS lavage for safety and efficacy.METHODS:At two centers, 200 patients undergoing colonoscopy for routine indications were randomized

  1. 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.

  2. 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.

  3. Effect of uranium (VI) on two sulphate-reducing bacteria cultures from a uranium mine site

    Microsoft Academic Search

    Mónica Martins; Maria Leonor Faleiro; Sandra Chaves; Rogério Tenreiro; Maria Clara Costa

    2010-01-01

    This work was conducted to assess the impact of uranium (VI) on sulphate-reducing bacteria (SRB) communities obtained from environmental samples collected on the Portuguese uranium mining area of Urgeiriça. Culture U was obtained from a sediment, while culture W was obtained from sludge from the wetland of that mine. Temperature gradient gel electrophoresis (TGGE) was used to monitor community changes

  4. The Geomicrobiological Role of Sulphate-Reducing Bacteria in Environments Contaminated by Petroleum Products

    Microsoft Academic Search

    Dorota Wolicka; Andrzej Borkowski

    2007-01-01

    This paper reviews the geomicrobiological role of sulphate-reducing bacteria (SRB) in environments contaminated with petroleum products and describes the habitats of SRB and their capacity for bioremediation in anaerobic conditions. Moreover, the participation of SRB in biocorrosion and formation of different minerals and sediments is discussed.

  5. Detection and Enumeration of Sulphate-Reducing Bacteria in Estuarine Sediments by Competitive PCR

    Microsoft Academic Search

    Ryuji Kondo; David B. Nedwell; Kevin J. Purdy; Silvana Queiroz Silva

    2004-01-01

    The distribution of sulphate-reducing bacteria (SRB) in the sediments of the Colne River estuary, Essex, UK covering different saline concentrations of sediment porewater was investigated by the use of quantitative competitive PCR. Here, we show that a new PCR primer set and a new quantitative method using PCR are useful tools for the detection and the enumeration of SRB in

  6. 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...

  7. Chondroitin sulfate

    MedlinePLUS

    ... with other products, including manganese ascorbate, glucosamine sulfate, glucosamine hydrochloride, or N-acetyl glucosamine. Research from a couple ... Early evidence suggests that chondroitin, with or without glucosamine hydrochloride, can reduce pain in people with Kashin-Beck ...

  8. 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.

  9. Bioenergetics of sulphate-reducing bacteria in relation to their environmental impact.

    PubMed

    Hamilton, W A

    1998-01-01

    The cellular physiology of the sulphate-reducing bacteria, and of other sulphidogenic species, is determined by the energetic requirements consequent upon their respiratory mode of metabolism with sulphate and other oxyanions of sulphur as terminal electron acceptors. As a further consequence of their, relatively, restricted catabolic activities and their requirement for conditions of anaerobiosis, sulphidogenic bacteria are almost invariably found in nature as component organisms within microbial consortia. The capacity to generate significant quantities of sulphide influences the overall metabolic activity and species diversity of these consortia, and is the root cause of the environmental impact of the sulphidogenic species: corrosion, pollution and the souring of hydrocarbon reservoirs. PMID:10022064

  10. Sulfur Isotope Enrichment during Maintenance Metabolism in the Thermophilic Sulfate-Reducing Bacterium Desulfotomaculum putei

    Microsoft Academic Search

    Mark M. Davidson; M. E. Bisher; Lisa M. Pratt; Jon Fong; Gordon Southam; Susan M. Pfiffner; Z. Reches; Tullis C. Onstott

    2009-01-01

    34 SSO4 indicate the differences in the isotopic composi- tions of the HS and SO4 2 in the eluent, respectively) for many modern marine sediments are in the range of 55 to 75‰, much greater than the 2t o46‰ 34 S (kinetic isotope enrichment) values commonly observed for microbial sulfate reduction in laboratory batch culture and chemostat experiments. It has

  11. 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.

  12. 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

  13. Reduction of Uranium(VI) under Sulfate-reducing Conditions in the Presence of Fe(III)-(hydr)oxides

    SciTech Connect

    Sani, Rajesh K.; Peyton, Brent M.; Amonette, James E.; Geesey, Gill G.

    2004-06-01

    U(VI) dissolved in a modified lactate-C medium (either sulfate- or lactate-limited) was reacted with a mixture of an Fe(III)-(hydr)oxide mineral (hematite, goethite, or ferrihydrite) and quartz under anoxic conditions and equivalent mineral surface areas. After sorption equilibration, the suspensions were inoculated with a sulfate-reducing bacterium (SRB, Desulfovibrio desulfuricans G20). Inoculation of the suspensions containing sulfate-limited medium yielded significant SRB growth, along with concomitant reduction of sulfate and removal of U(VI) from solution. Inoculation of the suspensions containing lactate-limited medium yielded similar results while lactate was still present. Once the lactate was depleted, however, some of the U that had been removed from solution was re-solubilized in the hematite treatment and, to a lesser extent, in the goethite treatment. No re-solubilization was observed in the lactate-limited ferrihydrite treatment even after a prolonged incubation of four months. Analysis by U L3-edge XANES spectroscopy of mineral specimens sampled without inoculation yielded a typical U(VI) spectrum. Mineral specimens sampled at the end of the experiment yielded spectra similar to that of uraninite, thus providing strong evidence for SRB-promoted removal of U(VI) from solution by reductive precipitation of uraninite. Consequently, U re-solubilization was attributed to re-oxidation of the uraninite by Fe(III) present in the (hydr)oxide phases. Our results thus suggest that inoculation with SRB mediates reduction of soluble U(VI) to an insoluble U(IV) oxide so long as a suitable electron donor is available. Depletion of the electron donor may result in partial re-oxidation of the U(IV) to soluble U(VI) species when the surfaces of crystalline Fe(III) (hydr)oxides are incompletely reduced by reaction with SRB-generated sulfide.

  14. Desulfovibrio legallis sp. nov.: a moderately halophilic, sulfate-reducing bacterium isolated from a wastewater digestor in Tunisia.

    PubMed

    Thabet, Olfa Ben Dhia; Wafa, Terres; Eltaief, Khelifi; Cayol, Jean-Luc; Hamdi, Moktar; Fauque, Guy; Fardeau, Marie-Laure

    2011-02-01

    A new moderately halophilic sulfate-reducing bacterium (strain H?(T) ) was enriched and isolated from a wastewater digestor in Tunisia. Cells were curved, motile rods (2-3 x 0.5 ?m). Strain H?(T) grew at temperatures between 22 and 43°C (optimum 35°C), and at pH between 5.0 and 9.2 (optimum 7.3-7.5). Strain H?(T) required salt for growth (1-45 g of NaCl/l), with an optimum at 20-30 g/l. Sulfate, sulfite, thiosulfate, and elemental sulfur were used as terminal electron acceptors but not nitrate and nitrite. Strain H?(T) utilized lactate, pyruvate, succinate, fumarate, ethanol, and hydrogen (in the presence of acetate and CO?) as electron donors in the presence of sulfate as electron acceptor. The main end-products from lactate oxidation were acetate with H? and CO?. The G + C content of the genomic DNA was 55%. The predominant fatty acids of strain H?(T) were C(15:0) iso (38.8%), C(16:0) (19%), and C(14:0) iso 3OH (12.2%), and menaquinone MK-6 was the major respiratory quinone. Phylogenetic analysis of the small-subunit (SSU) ribosomal RNA (rRNA) gene sequence indicated that strain H?(T) was affiliated to the genus Desulfovibrio. On the basis of SSU rRNA gene sequence comparisons and physiological characteristics, strain H?(T) is proposed to be assigned to a novel species of sulfate reducers of the genus Desulfovibrio, Desulfovibrio legallis sp. nov. (= DSM 19129(T) = CCUG 54389(T)). PMID:20814681

  15. 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...

  16. Aluminum and sulphate removal by a highly Al-resistant dissimilatory sulphate-reducing bacteria community.

    PubMed

    Martins, Mónica; Taborda, Rita; Silva, Gonçalo; Assunção, Ana; Matos, António Pedro; Costa, Maria Clara

    2012-09-01

    A highly Al-resistant dissimilatory sulphate-reducing bacteria community was isolated from sludge of the wetland of Urgeiriça mine (community W). This community showed excellent sulphate removal at the presence of Al³?. After 27 days of incubation, 73, 86 and 81% of sulphate was removed in the presence of 0.48, 0.90 and 1.30 mM of Al³?, respectively. Moreover, Al³? was simultaneously removed: 55, 85 and 78% of metal was removed in the presence of 0.48, 0.90 and 1.30 mM of Al³?, respectively. The dissociation of aluminium-lactate soluble complexes due to lactate consumption by dissimilatory sulphate-reducing bacteria can be responsible for aluminum removal, which probably precipitates as insoluble aluminium hydroxide. Phylogenetic analysis of 16S rRNA gene showed that this community was mainly composed by bacteria closely related to Desulfovibrio desulfuricans. However, bacteria affiliated to Proteus and Ralstonia were also present in the community. PMID:22367464

  17. Synthesis of bacteria promoted reduced graphene oxide-nickel sulfide networks for advanced supercapacitors.

    PubMed

    Zhang, Haiming; Yu, Xinzhi; Guo, Di; Qu, Baihua; Zhang, Ming; Li, Qiuhong; Wang, Taihong

    2013-08-14

    Supercapacitors with potential high power are useful and have attracted much attention recently. Graphene-based composites have been demonstrated to be promising electrode materials for supercapacitors with enhanced properties. To improve the performance of graphene-based composites further and realize their synthesis with large scale, we report a green approach to synthesize bacteria-reduced graphene oxide-nickel sulfide (BGNS) networks. By using Bacillus subtilis as spacers, we deposited reduced graphene oxide/Ni3S2 nanoparticle composites with submillimeter pores directly onto substrate by a binder-free electrostatic spray approach to form BGNS networks. Their electrochemical capacitor performance was evaluated. Compared with stacked reduced graphene oxide-nickel sulfide (GNS) prepared without the aid of bacteria, BGNS with unique nm-?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

  18. Oligonucleotide Microarray for 16S rRNA Gene-Based Detection of All Recognized Lineages of Sulfate-Reducing Prokaryotes in the Environment

    Microsoft Academic Search

    Alexander Loy; Angelika Lehner; Natuschka Lee; Justyna Adamczyk; Harald Meier; Jens Ernst; Karl-Heinz Schleifer; Michael Wagner

    2002-01-01

    For cultivation-independent detection of sulfate-reducing prokaryotes (SRPs) an oligonucleotide microarray consisting of 132 16S rRNA gene-targeted oligonucleotide probes (18-mers) having hierarchical and parallel (identical) specificity for the detection of all known lineages of sulfate-reducing prokaryotes (SRP-PhyloChip) was designed and subsequently evaluated with 41 suitable pure cultures of SRPs. The applicability of SRP- PhyloChip for diversity screening of SRPs in environmental

  19. 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.

  20. Evaluation of kinetic controls on sulfate reduction in a contaminated wetland-aquifer system 

    E-print Network

    Kneeshaw, Tara Ann

    2009-05-15

    )?????????????????????.???. 77 Figure 4.6 Abundance of methanogens (copies mcrA/ng DNA)..? ..????. 78 Figure 5.1 NOGEE placement for February 2008 experiments?.. ?. ???? 87 Figure 5.2 Rate results?????????????????.. ...?. ?? ... 95 Figure 5.3 Sulfate... reducing bacteria?????...?... ??????.??? 103 Figure 5.4 Iron reducing bacteria?????...?...???????..??? 104 Figure 5.5 Methanogens?????...?????...?????????? 105 xiv LIST OF TABLES Page Table...

  1. Isolation and Characterization of Strains CVO and FWKO B, Two Novel Nitrate-Reducing, Sulfide-Oxidizing Bacteria Isolated from Oil Field Brine

    PubMed Central

    Gevertz, Diane; Telang, Anita J.; Voordouw, Gerrit; Jenneman, Gary E.

    2000-01-01

    Bacterial strains CVO and FWKO B were isolated from produced brine at the Coleville oil field in Saskatchewan, Canada. Both strains are obligate chemolithotrophs, with hydrogen, formate, and sulfide serving as the only known energy sources for FWKO B, whereas sulfide and elemental sulfur are the only known electron donors for CVO. Neither strain uses thiosulfate as an energy source. Both strains are microaerophiles (1% O2). In addition, CVO grows by denitrification of nitrate or nitrite whereas FWKO B reduces nitrate only to nitrite. Elemental sulfur is the sole product of sulfide oxidation by FWKO B, while CVO produces either elemental sulfur or sulfate, depending on the initial concentration of sulfide. Both strains are capable of growth under strictly autotrophic conditions, but CVO uses acetate as well as CO2 as its sole carbon source. Neither strain reduces sulfate; however, FWKO B reduces sulfur and displays chemolithoautotrophic growth in the presence of elemental sulfur, hydrogen, and CO2. Both strains grow at temperatures between 5 and 40°C. CVO is capable of growth at NaCl concentrations as high as 7%. The present 16s rRNA analysis suggests that both strains are members of the epsilon subdivision of the division Proteobacteria, with CVO most closely related to Thiomicrospira denitrifcans and FWKO B most closely related to members of the genus Arcobacter. The isolation of these two novel chemolithotrophic sulfur bacteria from oil field brine suggests the presence of a subterranean sulfur cycle driven entirely by hydrogen, carbon dioxide, and nitrate. PMID:10831429

  2. [Development of mono- and associative cultures of sulphate-reducing bacteria and formation of exopolymeric complex].

    PubMed

    Purish, L M; Asaulenko, L H; Ostapchuk, A M

    2009-01-01

    Differences were found in development of the monoculture of sulphate-reducing bacteria Desulfovibrio sp. Kyiv-10 and artificial associations of cultures of sulphate reducing bacteria with heterotrophic satellites under development in a form of biofilm or plankton. Correlation between exopolymers synthesis in the biofilm and steel corrosion velocity has been found. Glucose, galactose, mannose, xylose, rhibose and nonidentified carbohydrates were found in the composition of exopolymers synthesized by monoculture Desulfovibrio sp. Kyiv-10 under its development in a form of biofilm. The biofilm and plankton cells of associative cultures synthesized exopolysaccharide which included rhamnose, arabinose and fucose. Glucose content in biofilm EPM was considerably higher (41.0055.9%) than in EPM of plankton cells (24.7-32.8). PMID:19938590

  3. 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

  4. Evidence of specialized bromate-reducing bacteria in a hollow fiber membrane biofilm reactor

    Microsoft Academic Search

    K. J. Martin; L. S. Downing; R. Nerenberg

    2009-01-01

    Bromate is a carcinogenic disinfection by-product formed from bromide during ozonation or advanced oxidation of drinking water. We previously observed bromate reduction in a hydrogen- based, denitrifying hollow fiber membrane biofilm reactor (MBfR). In this research, we investigated the potential existence of specialized bromate-reducing bacteria. Using denaturing gradient gel electrophoresis (DGGE), we compared the microbial ecology of two denitrifying MBfRs,

  5. Mir space station bacteria responses to modeled reduced gravity under starvation conditions

    Microsoft Academic Search

    Paul W. Baker; Laura G. Leff

    2006-01-01

    Isolates from the Mir space station identified as Pseudomonas sp. and Stenotrophomonas maltophilia were subjected to clinorotation to model reduced gravity conditions in water in slow turning lateral vessels (STLVs). To examine cells in varying physiological states, bacteria were enumerated based on the Live\\/Dead BacLight kit, DAPI (4?,6-diamidino-2-phenylindole) staining, fluorescent in situ hybridization (FISH), and colony forming units (CFU). Both

  6. Mir space station bacteria responses to modeled reduced gravity under starvation conditions

    Microsoft Academic Search

    Paul W. Baker; Laura G. Leff

    2006-01-01

    Isolates from the Mir space station identified as Pseudomonas sp. and Stenotrophomonas maltophilia were subjected to clinorotation to model reduced gravity conditions in water in slow turning lateral vessels (STLVs). To examine cells in varying physiological states, bacteria were enumerated based on the Live\\/Dead BacLight kit, DAPI (4',6-diamidino-2-phenylindole) staining, fluorescent in situ hybridization (FISH), and colony forming units (CFU). Both

  7. Treatment of Acid Mine Drainage by Sulphate-reducing Bacteria Using Low Cost Matrices

    Microsoft Academic Search

    M. C. Costa; M. Martins; C. Jesus; J. C. Duarte

    2008-01-01

    This paper reports a laboratory-scale investigation concerning the use of sulphate-reducing bacteria (SRB) in a semi-continuous\\u000a process, where column packed-bed type bioreactors were used for the treatment of acid mine drainage (AMD). The use of different\\u000a materials as solid matrices was tested and the performance of the bioremediation processes was discussed in terms of sulphate\\u000a and metals removal and acid

  8. Desulfovirgula thermocuniculi gen. nov., sp. nov., a thermophilic sulfate-reducer isolated from a geothermal underground mine in Japan.

    PubMed

    Kaksonen, Anna H; Spring, Stefan; Schumann, Peter; Kroppenstedt, Reiner M; Puhakka, Jaakko A

    2007-01-01

    A thermophilic, Gram-positive, endospore-forming, sulfate-reducing bacterial strain, designated RL80JIV(T), was isolated from a geothermally active underground mine in Japan. Cells were rod-shaped and motile. The temperature and pH ranges for growth were 61-80 degrees C (optimum at 69-72 degrees C) and pH 6.4-7.9 (optimum at pH 6.8-7.3), and the strain tolerated up to 0.5 % NaCl. Strain RL80JIV(T) utilized sulfate, sulfite, thiosulfate and elemental sulfur as electron acceptors. Electron donors utilized were H(2) in the presence of CO(2), and carboxylic acids. Fermentative growth occurred on lactate and pyruvate. The cell wall contained meso-diaminopimelic acid and the major respiratory isoprenoid quinone was menaquinone MK-7. Major whole-cell fatty acids were iso-C(15 : 0), iso-C(17 : 0) and C(16 : 0). Strain RL80JIV(T) was found to be affiliated with the thiosulfate-reducer Thermanaeromonas toyohensis DSM 14490(T) (90.9 % 16S rRNA gene sequence similarity) and with the sulfate-reducer Desulfotomaculum thermocisternum DSM 10259(T) (90.0 % similarity). Strain RL80JIV(T) is therefore considered to represent a novel species of a new genus, for which the name Desulfovirgula thermocuniculi gen. nov., sp. nov. is proposed. The type strain of Desulfovirgula thermocuniculi is RL80JIV(T) (=DSM 16036(T)=JCM 13928(T)). PMID:17220449

  9. Effects of dietary inorganic sulfate levels on growth performance and markers of intestinal inflammation in growing pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Co-products from the ethanol industry may contain moderate amounts of inorganic sulfur. In the digestive tract, inorganic sulfate can be reduced to hydrogen sulfide by sulfate-reducing bacteria. Hydrogen sulfide has been found to alter the inflammatory response in cell culture and rodent models, b...

  10. Role of sulfate in microbial transformations of environmental contaminants: Chlorinated aromatic compounds

    Microsoft Academic Search

    Patricia J. S. Colberg

    1990-01-01

    Despite recent progress made in describing microbial transformations that occur under anaerobic conditions, our understanding of the role sulfate?reducing bacteria may play in the remediation of environmental contaminants is still very limited. The objective of this mini?review is to summarize what is currently known of the metabolism of chlorinated aromatic compounds in the presence of sulfate. Sulfidogenic processes are discussed

  11. Microbial sulfate reduction under sequentially acidic conditions in an upflow anaerobic packed bed bioreactor

    Microsoft Academic Search

    Tony Jong; David L. Parry

    2006-01-01

    The aim of this study was to operate an upflow anaerobic packed bed reactor (UAPB) containing sulfate reducing bacteria (SRB) under acidic conditions similar to those found in acid mine drainage (AMD). The UAPB was filled with sand and operated under continuous flow at progressively lower pH and was shown to be capable of supporting sulfate reduction at pH values

  12. 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.

  13. 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.

  14. 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

  15. Recovery of humic-reducing bacteria from a diversity of environments.

    PubMed

    Coates, J D; Ellis, D J; Blunt-Harris, E L; Gaw, C V; Roden, E E; Lovley, D R

    1998-04-01

    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

  16. Nitrate?reducing and ammonium?oxidizing bacteria in the vadose zone of the chalk aquifer of England

    Microsoft Academic Search

    K. Whitelaw; J. F. Rees

    1980-01-01

    The vadose zone of the Chalk aquifer from two sites of different land use was found to contain large numbers of nitrate?reducing and ammonium?oxidizing bacteria. Relationships between the type of bacteria and nitrogen compounds produced showed that denitrification was occurring beneath the permanent grassland site, whereas the vadose zone beneath the fertilized arable site was essentially aerobic and little attenuation

  17. 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 ?M HS? h?1 in a stromatolite mat, 38 and 36 ?M HS? h?1 in a salt pond mat, and 27 and 18 ?M 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

  18. 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-? was suppressed by pCS. Further, pCS decreased the percentage of IFN-?-producing Th1 cells. Our results suggest that intestinal bacteria-derived pCS suppressesTh1-type cellular immune responses. PMID:24161588

  19. ENUMERATION, ISOLATION, AND CHARACTERIZATION OF ACETOGENIC BACTERIA ASSOCIATED WITH SEAGRASS ROOTS (POSTER SESSION)

    EPA Science Inventory

    Seagrasses are rooted in anoxic, sulfate-reducing sediments. However, the seagrass root is oxygenated during the daytime, becoming anoxic at night. Root thin sections hydridized with 33P-labeled probes revealed the presence of acetogenic and sulfate-reducing bacteria in the rhizo...

  20. ENUMERATION, ISOLATION, AND CHARACTERIZATION OF ACETOGENIC BACTERIA ASSOCIATED WITH SEAGRASS ROOTS

    EPA Science Inventory

    Seagrasses are rooted in anoxic, sulfate-reducing sediments. However, the seagrass root is oxygenated during the daytime, becoming anoxic at night. Root thin sections hydridized with 33P-labeled probes revealed the presence of acetogenic and sulfate-reducing bacteria in the rhizo...

  1. Suspension Array Analysis of 16S rRNA from Fe- and SO 2-4 Reducing Bacteria in Uranium Contaminated Sediments Undergoing Bioremediation

    SciTech Connect

    Chandler, Darrell P.; Jarrell, Ann E.; Roden , Eric R.; Golova, Julia; Chernov, Boris; Schipma, Matthew; Peacock, Aaron D.; Long, Philip E.

    2006-07-15

    A 16S rRNA-targeted tunable bead array 2 was developed and applied in a retrospective analysis of metal- and sulfate-reducing bacteria in contaminated subsurface 4 sediments undergoing in situ U(VI) bioremediation. Total RNA was extracted from subsurface sediments and interrogated directly, without employing a polymerase chain 6 reaction step. Bead array validation studies with total RNA derived from 26 isolates indicate that the behavior and response of the 16S rRNA-targeted oligonucleotide probes 8 could not be predicted based upon primary nucleic acid sequence. Likewise, signal intensity (absolute or normalized) could not be used to assess the relative abundance of 10 one organism (or rRNA) to another. Nevertheless, microbial community structure and dynamics through time and space and as measured by the rRNA-targeted bead array were 12 consistent with previous data acquired at the site, where indigenous sulfate and iron reducing bacteria and Desulfotomaculum near neighbors were the most responsive to a 14 change in injected acetate concentrations. Interpreting bead array data was best accomplished by analyzing the relative change in probe response over spatially and 16 temporally related samples, and by only considering the response of one probe to itself in relation to a background (reference) environmental sample. By limiting the data 18 interpretation in this manner and placing it within the context of supporting geochemical and microbiological analyses, we conclude that ecologically relevant and meaningful 20 information can be derived from direct microarray analysis of rRNA in uncharacterized environmental samples, even amidst current analytical uncertainty surrounding individual 22 probe behavior on tunable bead arrays.

  2. Kinetics of bacterial sulfate reduction in an activated sludge plant

    Microsoft Academic Search

    Kjeld Ingvorsen; Marianne Yde Nielsen; Catherine Joulian

    2003-01-01

    The kinetics of sulfate reduction and cell densities of sulfate-reducing bacteria (SRB) were determined in activated sludge at Aalborg East wastewater treatment plant, a modern 100?000 person equivalent plant, where SRB are subjected to alternating cycles of oxic and anoxic conditions. The number of SRB was relatively constant over the year, ranging from 2.1×105 to 1.1×106 cells ml?1 as determined

  3. Biological sulfate reduction using gas-lift reactors fed with hydrogen and carbon dioxide as energy and carbon source

    SciTech Connect

    Houten, R.T. van; Hulshoff Pol, L.W.; Lettinga, G. (Wageningen Agricultural Univ. (Netherlands). Dept. of Environmental Technology)

    1994-08-20

    Feasibility and engineering aspects of biological sulfate reduction in gas-lift reactors were studied. Hydrogen and carbon dioxide were used as energy and carbon source. Attention was paid to biofilm formation, sulfide toxicity, sulfate conversion rate optimization, and gas-liquid mass transfer limitations. Sulfate-reducing bacteria formed stable biofilms on pumice particles. Biofilm formation was not observed when basalt particles were used. However, use of basalt particles led to the formation of granules of sulfate-reducing biomass. The sulfate-reducing bacteria, grown on pumice, easily adapted to free H[sub 2]S concentrations up to 450 mg/L. Biofilm growth rate then equilibrated biomass loss rate. These high free H[sub 2]S concentrations caused reversible inhibition rather than acute toxicity. When free H[sub 2]S concentrations were kept below 450 mg/L, a maximum sulfate conversion rate of 30 g SO[sub 4][sup 2[minus

  4. Impact of sulphate-reducing bacteria on the performance of engineering materials.

    PubMed

    Javaherdashti, Reza

    2011-09-01

    Microbiologically Influenced Corrosion (MIC) is an electrochemical corrosion influenced by the presence/action of biological agents such as, but not limited to, bacteria. One of the key elements of MIC is sulphate-reducing bacteria (SRB). There are still many misunderstandings about these bacteria, their role in the deterioration of engineering materials and their importance over other types of corrosion-related micro-/macro-organisms. SRB do not require oxygen, yet they can be found in oxygenated environments; they are capable of tolerating a relative wide range of temperature, pH, chloride concentration and pressure values. Not only can SRB have deteriorating impact on engineering materials, they are also capable of inducing harm to health and agriculture. In this paper, after reviewing facts and figures regarding ecological and economical impacts of corrosion in general and MIC, in particular, the central concept of MIC, that is, biofilm formation and its deterioration mechanisms and the role of SRB in such mechanisms are described. Also, the possible enhancing role of SRB on stress corrosion cracking of steels and the controversial concept of no relationship between the number of SRB and corrosion rate are addressed and reviewed. PMID:21786108

  5. Sulfate reduction and methanogenesis in marine sediments

    NASA Technical Reports Server (NTRS)

    Oremland, R. S.; Taylor, B. F.

    1978-01-01

    Methanogenesis and sulfate-reduction were followed in laboratory incubations of sediments taken from tropical seagrass beds. Methanogenesis and sulfate-reduction occurred simultaneously in sediments incubated under N2, thereby indicating that the two processes are not mutually exclusive. Sediments incubated under an atmosphere of H2 developed negative pressures due to the oxidation of H2 by sulfate-respiring bacteria. H2 also stimulated methanogenesis, but methanogenic bacteria could not compete for H2 with the sulfate-respiring bacteria.

  6. Nitrate-reducing, sulfide-oxidizing bacteria as microbial oxidants for rapid biological sulfide removal

    Microsoft Academic Search

    Bart De Gusseme; Peter De Schryver; Kim Verbeken; Pascal Boeckx; Willy Verstraete

    2009-01-01

    The emission of hydrogen sulfide into the atmosphere of sewer systems\\u000a induces the biological production of sulfuric acid, causing severe\\u000a concrete corrosion. As a possible preventive solution, a microbial\\u000a consortium of nitrate-reducing, sulfide-oxidizing bacteria (NR-SOB) was\\u000a enriched in a continuously stirred tank reactor in order to develop a\\u000a biological technique for the removal of dissolved sulfide. The\\u000a consortium, dominated by

  7. 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

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

    SciTech Connect

    Hamilton-Brehm, Scott [ORNL; Gibson, Robert [NIOZ Royal Netherlands Institute for Sea Research; Green, Stefan [University of Illinois, Chicago; Hopmans, Ellen [NIOZ Royal Netherlands Institute for Sea Research; Schouten, Stefan [NIOZ Royal Netherlands Institute for Sea Research; van der Meer, Marcel T. J. [NIOZ Royal Netherlands Institute for Sea Research; Shields, John [University of Georgia, Athens, GA; S. Damste, Jaap S. [NIOZ Royal Netherlands Institute for Sea Research; Elkins, James G [ORNL

    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.

  9. 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).

  10. Degradation of o-xylene and m-xylene by a novel sulfate-reducer belonging to the genus Desulfotomaculum.

    PubMed

    Morasch, Barbara; Schink, Bernhard; Tebbe, Christoph C; Meckenstock, Rainer U

    2004-06-01

    A strictly anaerobic bacterium, strain OX39, was isolated with o-xylene as organic substrate and sulfate as electron acceptor from an aquifer at a former gasworks plant contaminated with aromatic hydrocarbons. Apart from o-xylene, strain OX39 grew on m-xylene and toluene and all three substrates were oxidized completely to CO(2). Induction experiments indicated that o-xylene, m-xylene, and toluene degradation were initiated by different specific enzymes. Methylbenzylsuccinate was identified in supernatants of cultures grown on o-xylene and m-xylene, and benzylsuccinate was detected in supernatants of toluene-grown cells, thus indicating that degradation was initiated in all three cases by fumarate addition to the methyl group. Strain OX39 was sensitive towards sulfide and depended on Fe(II) in the medium as a scavenger of the produced sulfide. Analysis of the PCR-amplified 16S rRNA gene revealed that strain OX39 affiliates with the gram-positive endospore-forming sulfate reducers of the genus Desulfotomaculum and is the first hydrocarbon-oxidizing bacterium in this genus. PMID:15127183

  11. Isolation and characterization of a new spore-forming sulfate-reducing bacterium growing by complete oxidation of catechol.

    PubMed

    Kuever, J; Kulmer, J; Jannsen, S; Fischer, U; Blotevogel, K H

    1993-01-01

    A new mesophilic sulfate-reducing bacterium, strain Groll, was isolated from a benzoate enrichment culture inoculated with black mud from a freshwater ditch. The isolate was a spore-forming, rod-shaped, motile, gram-positive bacterium. This isolate was able of complete oxidation of several aromatic compounds including phenol, catechol, benzoate, p- and m-cresol, benzyl alcohol and vanillate. With hydrogen and carbon dioxide, formate or O-methylated aromatic compounds, autotrophic growth during sulfate reduction or homoacetogenesis was demonstrated. Lactate was not used as a substrate. SO4(2-), SO3(2-), and S2O3(2-) were utilized as electron acceptors. Although strain Groll originated from a freshwater habitat, salt concentrations of up to 30 g.l-1 were tolerated. The optimum temperature for growth was 35-37 degrees C. The G + C content of DNA was 42.1 mol%. This isolate is described as a new species of the genus Desulfotomaculum. PMID:8481092

  12. Bacteria associated with a tree-killing insect reduce concentrations of plant defense compounds.

    PubMed

    Boone, Celia K; Keefover-Ring, Ken; Mapes, Abigail C; Adams, Aaron S; Bohlmann, Jörg; Raffa, Kenneth F

    2013-07-01

    Bark beetles encounter a diverse array of constitutive and rapidly induced terpenes when attempting to colonize living conifers. Concentrations of these compounds at entry sites can rapidly reach levels toxic to beetles, their brood, and fungal symbionts. Large numbers of beetles can overwhelm tree defenses via pheromone-mediated mass attacks, but the mechanisms are poorly understood. We show that bacteria associated with mountain pine beetles can metabolize monoterpenes and diterpene acids. The abilities of different symbionts to reduce concentrations of different terpenes appear complementary. Serratia reduced concentrations of all monoterpenes applied to media by 55-75 %, except for ?-pinene. Beetle-associated Rahnella reduced (-)- and (+)-?-pinene by 40 % and 45 %, respectively. Serratia and Brevundimonas reduced diterpene abietic acid levels by 100 % at low concentrations. However, high concentrations exhausted this ability, suggesting that opposing rates of bacterial metabolism and plant induction of terpenes are critical. The two major fungal symbionts of mountain pine beetle, Grosmannia clavigera and Ophiostoma montium were highly susceptible to abietic acid. Grosmannia clavigera did not reduce total monoterpene concentrations in lodgepole pine turpentine. We propose the ability of bark beetles to exert landscape-scale impacts may arise partly from micro-scale processes driven by bacterial symbionts. PMID:23807433

  13. Mir space station bacteria responses to modeled reduced gravity under starvation conditions

    NASA Astrophysics Data System (ADS)

    Baker, Paul W.; Leff, Laura G.

    2006-01-01

    Isolates from the Mir space station identified as Pseudomonas sp. and Stenotrophomonas maltophilia were subjected to clinorotation to model reduced gravity conditions in water in slow turning lateral vessels (STLVs). To examine cells in varying physiological states, bacteria were enumerated based on the Live/Dead BacLight kit, DAPI (4',6-diamidino-2-phenylindole) staining, fluorescent in situ hybridization (FISH), and colony forming units (CFU). Both Pseudomonas sp. and S. maltophilia showed a slight increase in abundance over time but only cells of Pseudomonas sp. were affected by modeled reduced gravity. For Pseudomonas sp. numbers of DAPI stained cells were significantly higher under modeled reduced gravity compared to normal gravity. In addition, the abundance of cells attached to stainless steel disks, on one sampling date, was greater for the Pseudomonas isolate under modeled reduced gravity than normal gravity. The isolates examined did not appear to appreciably enter into a viable, but not culturable state during the experiments. In general, differences between treatments were not great, demonstrating that responses to reduced gravity are less apparent under starvation conditions, compared to earlier studies which used more rich nutrient sources.

  14. Hexagonal Platelet-like Magnetite as a Biosignature of Thermophilic Iron-Reducing Bacteria and Its Applications to the Exploration of the Modern Deep, Hot Biosphere and the Emergence of Iron-Reducing Bacteria in Early Precambrian Oceans

    PubMed Central

    2012-01-01

    Abstract Dissimilatory iron-reducing bacteria are able to enzymatically reduce ferric iron and couple to the oxidation of organic carbon. This mechanism induces the mineralization of fine magnetite crystals characterized by a wide distribution in size and irregular morphologies that are indistinguishable from authigenic magnetite. Thermoanaerobacter are thermophilic iron-reducing bacteria that predominantly inhabit terrestrial hot springs or deep crusts and have the capacity to transform amorphous ferric iron into magnetite with a size up to 120?nm. In this study, I first characterize the formation of hexagonal platelet-like magnetite of a few hundred nanometers in cultures of Thermoanaerobacter spp. strain TOR39. Biogenic magnetite with such large crystal sizes and unique morphology has never been observed in abiotic or biotic processes and thus can be considered as a potential biosignature for thermophilic iron-reducing bacteria. The unique crystallographic features and strong ferrimagnetic properties of these crystals allow easy and rapid screening for the previous presence of iron-reducing bacteria in deep terrestrial crustal samples that are unsuitable for biological detection methods and, also, the search for biogenic magnetite in banded iron formations that deposited only in the first 2 billion years of Earth with evidence of life. Key Words: Biosignatures—Magnetite—Iron-reducing bacteria—Deep subsurface biosphere—Banded iron formation. Astrobiology 12, 1100–1108. PMID:23145573

  15. Evaluation of the stability of arsenic immobilized by microbial sulfate reduction using TCLP extractions and long-term leaching techniques

    Microsoft Academic Search

    Tony Jong; David L. Parry

    2005-01-01

    An investigation was conducted to evaluate the stability or leachability of arsenic immobilized by microbial sulfate reduction. Anoxic solid-phase samples taken from a bioreactor previously used to treat metal and As contaminated water using sulfate reducing bacteria (SRB) were subjected to the toxicity characteristic leaching procedure (TCLP) and long-term column leaching tests. The results from TCLP experiments showed that the

  16. Combination of essential oils and antibiotics reduce antibiotic resistance in plasmid-conferred multidrug resistant bacteria.

    PubMed

    Yap, Polly Soo Xi; Lim, Swee Hua Erin; Hu, Cai Ping; Yiap, Beow Chin

    2013-06-15

    In this study we investigated the relationship between several selected commercially available essential oils and beta-lactam antibiotics on their antibacterial effect against multidrug resistant bacteria. The antibacterial activity of essential oils and antibiotics was assessed using broth microdilution. The combined effects between essential oils of cinnamon bark, lavender, marjoram, tea tree, peppermint and ampicillin, piperacillin, cefazolin, cefuroxime, carbenicillin, ceftazidime, meropenem, were evaluated by means of the checkerboard method against beta-lactamase-producing Escherichia coli. In the latter assays, fractional inhibitory concentration (FIC) values were calculated to characterize interaction between the combinations. Substantial susceptibility of the bacteria toward natural antibiotics and a considerable reduction in the minimum inhibitory concentrations (MIC) of the antibiotics were noted in some paired combinations of antibiotics and essential oils. Out of 35 antibiotic-essential oil pairs tested, four of them showed synergistic effect (FIC?0.5) and 31 pairs showed no interaction (FIC>0.5-4.0). The preliminary results obtained highlighted the occurrence of a pronounced synergistic relationship between piperacillin/cinnamon bark oil, piperacillin/lavender oil, piperacillin/peppermint oil as well as meropenem/peppermint oil against two of the three bacteria under study with a FIC index in the range 0.26-0.5. The finding highlighted the potential of peppermint, cinnamon bark and lavender essential oils being as antibiotic resistance modifying agent. Reduced usage of antibiotics could be employed as a treatment strategy to decrease the adverse effects and possibly to reverse the beta-lactam antibiotic resistance. PMID:23537749

  17. Aluminum sulfate significantly reduces the skin test response to common allergens in sensitized patients

    Microsoft Academic Search

    C Steven Smith; Scott A Smith; Thomas J Grier; David E Justus

    2006-01-01

    BACKGROUND: Avoidance of allergens is still recommended as the first and best way to prevent allergic illnesses and their comorbid diseases. Despite a variety of attempts there has been very limited success in the area of environmental control of allergic disease. Our objective was to identify a non-invasive, non-pharmacological method to reduce indoor allergen loads in atopic persons' homes and

  18. Multiple sulfur isotope signatures of sulfite and thiosulfate reduction by the model dissimilatory sulfate-reducer, Desulfovibrio alaskensis str. G20

    PubMed Central

    Leavitt, William D.; Cummins, Renata; Schmidt, Marian L.; Sim, Min S.; Ono, Shuhei; Bradley, Alexander S.; Johnston, David T.

    2014-01-01

    Dissimilatory sulfate reduction serves as a key metabolic carbon remineralization process in anoxic marine environments. Sulfate reducing microorganisms can impart a wide range in mass-dependent sulfur isotopic fractionation. As such, the presence and relative activity of these organisms is identifiable from geological materials. By extension, sulfur isotope records are used to infer the redox balance of marine sedimentary environments, and the oxidation state of Earth's oceans and atmosphere. However, recent work suggests that our understanding of microbial sulfate reduction (MSRs) may be missing complexity associated with the presence and role of key chemical intermediates in the reductive process. This study provides a test of proposed metabolic models of sulfate reduction by growing an axenic culture of the well-studied MSRs, Desulfovibrio alaskensis strain G20, under electron donor limited conditions on the terminal electron acceptors sulfate, sulfite or thiosulfate, and tracking the multiple S isotopic consequences of each condition set. The dissimilatory reduction of thiosulfate and sulfite produce unique minor isotope effects, as compared to the reduction of sulfate. Further, these experiments reveal a complex biochemistry associated with sulfite reduction. That is, under high sulfite concentrations, sulfur is shuttled to an intermediate pool of thiosulfate. Site-specific isotope fractionation (within thiosulfate) is very large (34? ~ 30‰) while terminal product sulfide carries only a small fractionation from the initial sulfite (34? < 10‰): a signature similar in magnitude to sulfate and thiosulfate reduction. Together these findings show that microbial sulfate reduction (MSR) is highly sensitive to the concentration of environmentally important sulfur-cycle intermediates (sulfite and thiosulfate), especially when thiosulfate and the large site-specific isotope effects are involved. PMID:25505449

  19. Nitrate-reducing, sulfide-oxidizing bacteria as microbial oxidants for rapid biological sulfide removal.

    PubMed

    De Gusseme, Bart; De Schryver, Peter; De Cooman, Michaël; Verbeken, Kim; Boeckx, Pascal; Verstraete, Willy; Boon, Nico

    2009-01-01

    The emission of hydrogen sulfide into the atmosphere of sewer systems induces the biological production of sulfuric acid, causing severe concrete corrosion. As a possible preventive solution, a microbial consortium of nitrate-reducing, sulfide-oxidizing bacteria (NR-SOB) was enriched in a continuously stirred tank reactor in order to develop a biological technique for the removal of dissolved sulfide. The consortium, dominated by Arcobacter sp., was capable of removing 99% of sulfide. Stable isotope fractioning of the sulfide indicated that the oxidation was a biological process. The capacity of the NR-SOB consortium for rapid removal of sulfide was demonstrated by using it as an inoculum in synthetic and real sewage. Removal rates up to 52 mg sulfide-S g VSS(-1) h(-1) were achieved, to our knowledge the highest removal rate reported so far for freshwater species in the absence of molecular oxygen. Further long-term incubation experiments revealed the capacity of the bacteria to oxidize sulfide without the presence of nitrate, suggesting that an oxidized redox reserve is present in the culture. PMID:19120464

  20. The performance, kinetics and microbiology of sulfidogenic fluidized-bed treatment of acidic metal- and sulfate-containing wastewater

    Microsoft Academic Search

    A. H. Kaksonen; J. J. Plumb; W. J. Robertson; M. Riekkola-Vanhanen; P. D. Franzmann; J. A. Puhakka

    2006-01-01

    A sulfidogenic fluidized-bed reactor (FBR) process was developed for treating acidic metal- and sulfate-containing wastewater. The process operating parameters were determined and the bacterial diversity of the FBR was described. The process was based on sulfate reduction by sulfate-reducing bacteria (SRB), precipitation of metals as sulfides with the biogenic H2S and neutralization of the water with biologically produced bicarbonate alkalinity.

  1. Effect of thermophilic sulphate-reducing bacteria (Desulfotomaculum geothermicum) isolated from Indian petroleum refinery on the corrosion of mild steel

    Microsoft Academic Search

    Balakrishnan Anandkumar; Aruliah Rajasekar; G. Venkatachari; Sundaram Maruthamuthu

    The role of thermophilic sulphate-reducing bacteria (SRB) Desulfotomaculum geothermicum in mild steel corrosion was evaluated by electrochemical study and surface analysis technique. In the presence of D. geo- thermicum, the corrosion rate was 0.0698 mmpy at 50°C, which was higher when compared to control. Polarization study revealed that the bacteria enhanced cathodic reaction and suppressed anodic reaction. XRD data revealed

  2. Impedimetric immunosensor doped with reduced graphene sheets fabricated by controllable electrodeposition for the non-labelled detection of bacteria

    Microsoft Academic Search

    Yi Wan; Zhifeng Lin; Dun Zhang; Yi Wang; Baorong Hou

    2011-01-01

    A facile, sensitive and reliable impedimetric immunosensor doped with reduced graphene sheets (RGSs) and combined with a controllable electrodeposition technique was developed for the selective detection of marine pathogenic sulphate-reducing bacteria (SRB). The morphology of RGSs and the electrochemical properties of RGSs-doped chitosan (CS) nanocomposite film were investigated by atomic force microscopy, Fourier transform infrared spectroscopy, and cyclic voltammetry (CV).

  3. Evaluation of feed COD\\/sulfate ratio as a control criterion for the biological hydrogen sulfide production and lead precipitation

    Microsoft Academic Search

    Antonio Velasco; Martha Ram ´ õrez; Tania Volke-Sep ´ ulveda; Armando Gonzalez-S; Sergio Revah

    The ability of sulfate-reducing bacteria to produce hydrogen sulfide and the high affinity of sulfide to react with divalent metallic cations represent an excellent option to remove heavy metals from wastewater. Different parameters have been proposed to control the hydrogen sulfide production by anaerobic bacteria, such as the organic and sulfate loading rates and the feed COD\\/SO42? ratio. This work

  4. Influence of electron donor on the minimum sulfate concentration required for sulfate reduction in a petroleum hydrocarbon-contaminated aquifer

    SciTech Connect

    Vroblesky, D.A.; Bradley, P.M.; Chapelle, F.H. [Geological Survey, Columbia, SC (United States)] [Geological Survey, Columbia, SC (United States)

    1996-04-01

    Fluctuations in the availability of electron donor (petroleum hydrocarbons) affected the competition between sulfate-reducing bacteria (SRB) and methanogenic bacteria (MB) for control of electron flow in a petroleum hydrocarbon-contaminated aquifer. The data suggest that abundant electron donor availability allowed MB to sequester a portion of the electron flow even when sulfate was present in sufficient concentrations to support sulfate reduction. For example, in an area of abundant electron-donor availability, SRB appeared to be unable to sequester the electron flow from MB in the presence of 1.4 mg/L sulfate. The data also suggest that when electron-donor availability was limited, SRB outcompeted MB for available substrate at a lower concentration of sulfate than when electron donor was plentiful. For example, in an area of limited electron-donor availability, SRB appeared to maintain dominance of electron flow at sulfate concentrations less than 1 mg/L. The presence of abundant electron donor and a limited amount of sulfate reduced competition for available substrate, allowing both SRB and MB to metabolize available substrates concurrently. 34 refs., 5 figs.

  5. ANAEROBIC BIODEGRADATION OF O-, M- AND P-CRESOL BY SULFATE-REDUCING BACTERIAL ENRICHMENT CULTURES OBTAINED FROM A SHALLOW ANOXIC AQUIFER

    EPA Science Inventory

    Sulfate-reducing bacterial enrichments were obtained from a shallow anoxic aquifer for their ability to metabolize either o-, or p-cresol. C/MS and simultaneous adaptation experiments suggested that the anaerobic decomposition of p-cresol proceeds by the initial oxidation of the ...

  6. ENDOPHYTIC BACTERIA FROM SEEDS OF NICOTIANA TABACUM CAN REDUCE CADMIUM PHYTOTOXICITY

    Microsoft Academic Search

    Chiara Mastretta; Safiyh Taghavi; Daniel van der Lelie; Alessio Mengoni; Francesca Galardi; Christina Gonnelli; Tanja Barac; Jana Boulet; Nele Weyens; Jaco Vangronsveld

    2009-01-01

    Although endophytic bacteria seem to have a close association with their host plant, little is known about the influence of seed endophytic bacteria on initial plant development and on their interactions with plants under conditions of metal toxicity. In order to further elucidate this close relationship, we isolated endophytic bacteria from surface sterilized Nicotiana tabacum seeds that were collected from

  7. ACETOGENIC BACTERIA ASSOCIATED WITH SEAGRASS ROOTS

    EPA Science Inventory

    Seagrasses are adapted to being rooted in reduced, anoxic sediments with high rates of sulfate reduction. During the day, an oxygen gradient is generated around the roots, becoming anoxic at night. Thus, obligate anaerobic bacteria in the rhizosphere have to tolerate elevated oxy...

  8. Hexagonal platelet-like magnetite as a biosignature of thermophilic iron-reducing bacteria and its applications to the exploration of the modern deep, hot biosphere and the emergence of iron-reducing bacteria in early precambrian oceans.

    PubMed

    Li, Yi-Liang

    2012-12-01

    Dissimilatory iron-reducing bacteria are able to enzymatically reduce ferric iron and couple to the oxidation of organic carbon. This mechanism induces the mineralization of fine magnetite crystals characterized by a wide distribution in size and irregular morphologies that are indistinguishable from authigenic magnetite. Thermoanaerobacter are thermophilic iron-reducing bacteria that predominantly inhabit terrestrial hot springs or deep crusts and have the capacity to transform amorphous ferric iron into magnetite with a size up to 120?nm. In this study, I first characterize the formation of hexagonal platelet-like magnetite of a few hundred nanometers in cultures of Thermoanaerobacter spp. strain TOR39. Biogenic magnetite with such large crystal sizes and unique morphology has never been observed in abiotic or biotic processes and thus can be considered as a potential biosignature for thermophilic iron-reducing bacteria. The unique crystallographic features and strong ferrimagnetic properties of these crystals allow easy and rapid screening for the previous presence of iron-reducing bacteria in deep terrestrial crustal samples that are unsuitable for biological detection methods and, also, the search for biogenic magnetite in banded iron formations that deposited only in the first 2 billion years of Earth with evidence of life. PMID:23145573

  9. Effect of electron donor source on the treatment of Cr(VI)-containing textile wastewater using sulfate-reducing fluidized bed reactors (FBRs).

    PubMed

    Cirik, Kevser; Dursun, Nesrin; Sahinkaya, Erkan; Cinar, Ozer

    2013-04-01

    The treatment of Cr(VI) containing textile wastewater was studied in ethanol and glucose-fed sulfate-reducing fluidized bed reactors at 35°C for around 250 days. The synthetic wastewater contained Cr(VI) (5-45 mg L(-1)), azo dye (Remazol Brilliant Violet 5R) (100-200 mg L(-1)), sulfate (2000 mg L(-1)) and ethanol or glucose (2000 mg L(-1) chemical oxygen demand (COD)). The robustness of two FBRs was assessed under varying Cr(VI) and azo dye loadings. Both reactors performed well in terms of COD, sulfate, color and Cr(VI) removals. However, ethanol-fed FBR performed better than glucose-fed one. The COD, sulfate, chromium and color removals at the highest Cr(VI) concentration (45 mg L(-1)) in ethanol-fed FBR were around 75%, 95%, 93%, and 99%, respectively. Further increase in influent Cr(VI) concentration adversely effected reactor performance. The COD, sulfate, chromium and color removals at 45 mg L(-1) Cr(VI) in glucose-fed FBR were around 60%, 50%, 93%, and 76%, respectively. PMID:23454387

  10. Iron-reducing bacteria accumulate ferric oxyhydroxide nanoparticle aggregates that may support planktonic growth

    SciTech Connect

    Luef, Birgit; Fakra, Sirine C.; Csencsits, Roseann; Wrighton, Kelly C.; Williams, Kenneth H.; Wilkins, Michael J.; Downing, Kenneth H.; Long, Philip E.; Comolli, Luis R.; Banfield, Jillian F.

    2013-02-04

    Iron-reducing bacteria (FeRB) play key roles in anaerobic metal and carbon cycling and carry out biogeochemical transformations that can be harnessed for environmental bioremediation. A subset of FeRB require direct contact with Fe(III) bearing minerals for dissimilatory growth, yet these bacteria must move between mineral particles. Further, they proliferate in planktonic consortia during biostimulation experiments. Thus, a key question is how such organisms can sustain growth under these conditions. Here we characterized planktonic microbial communities sampled from an aquifer in Rifle, Colorado, USA close to the peak of iron reduction following in situ acetate amendment. Samples were cryo-plunged on site and subsequently examined using correlated 2- and 3- dimensional cryogenic transmission electron microscopy (cryo-TEM) and scanning transmission X-ray microscopy (STXM). Most cells had their outer membranes decorated with up to 150 nm diameter aggregates composed of a few nm wide amorphous, Fe-rich nanoparticles. Fluorescent in situ hybridization of lineage-specific probes applied to rRNA of cells subsequently imaged via cryo-TEM identified Geobacter spp., a well studied group of FeRB. STXM results at the Fe L2,3 absorption edges indicate that nanoparticle aggregates contain a variable mixture of Fe(II)-Fe(III), and are generally enriched in Fe(III). Geobacter bemidjiensis cultivated anaerobically in the laboratory on acetate and hydrous ferric oxyhydroxides also accumulated mixed valence nanoparticle aggregates. In field-collected samples, FeRB with a wide variety of morphologies were associated with nano-aggregates, indicating that cell-surface Fe(III) accumulation may be a general mechanism by which FeRB can grow while in planktonic suspension.

  11. Iron-reducing bacteria accumulate ferric oxyhydroxide nanoparticle aggregates that may support planktonic growth

    PubMed Central

    Luef, Birgit; Fakra, Sirine C; Csencsits, Roseann; Wrighton, Kelly C; Williams, Kenneth H; Wilkins, Michael J; Downing, Kenneth H; Long, Philip E; Comolli, Luis R; Banfield, Jillian F

    2013-01-01

    Iron-reducing bacteria (FeRB) play key roles in anaerobic metal and carbon cycling and carry out biogeochemical transformations that can be harnessed for environmental bioremediation. A subset of FeRB require direct contact with Fe(III)-bearing minerals for dissimilatory growth, yet these bacteria must move between mineral particles. Furthermore, they proliferate in planktonic consortia during biostimulation experiments. Thus, a key question is how such organisms can sustain growth under these conditions. Here we characterized planktonic microbial communities sampled from an aquifer in Rifle, Colorado, USA, close to the peak of iron reduction following in situ acetate amendment. Samples were cryo-plunged on site and subsequently examined using correlated two- and three-dimensional cryogenic transmission electron microscopy (cryo-TEM) and scanning transmission X-ray microscopy (STXM). The outer membranes of most cells were decorated with aggregates up to 150?nm in diameter composed of ?3?nm wide amorphous, Fe-rich nanoparticles. Fluorescent in situ hybridization of lineage-specific probes applied to rRNA of cells subsequently imaged via cryo-TEM identified Geobacter spp., a well-studied group of FeRB. STXM results at the Fe L2,3 absorption edges indicate that nanoparticle aggregates contain a variable mixture of Fe(II)–Fe(III), and are generally enriched in Fe(III). Geobacter bemidjiensis cultivated anaerobically in the laboratory on acetate and hydrous ferric oxyhydroxides also accumulated mixed-valence nanoparticle aggregates. In field-collected samples, FeRB with a wide variety of morphologies were associated with nano-aggregates, indicating that cell surface Fe(III) accumulation may be a general mechanism by which FeRB can grow while in planktonic suspension. PMID:23038172

  12. Transformation of vivianite by anaerobic nitrate-reducing iron-oxidizing bacteria.

    PubMed

    Miot, J; Benzerara, K; Morin, G; Bernard, S; Beyssac, O; Larquet, E; Kappler, A; Guyot, F

    2009-06-01

    In phosphate-rich environments, vivianite (Fe(II)(3)(PO(4))(2), 8H(2)O) is an important sink for dissolved Fe(II) and is considered as a very stable mineral due to its low solubility at neutral pH. In the present study, we report the mineralogical transformation of vivianite in cultures of the nitrate-reducing iron-oxidizing bacterial strain BoFeN1 in the presence of dissolved Fe(II). Vivianite was first transformed into a greenish phase consisting mostly of an amorphous mixed valence Fe-phosphate. This precipitate became progressively orange and the final product of iron oxidation consisted of an amorphous Fe(III)-phosphate. The sub-micrometer analysis by scanning transmission X-ray microscopy of the iron redox state in samples collected at different stages of the culture indicated that iron was progressively oxidized at the contact of the bacteria and at a distance from the cells in extracellular minerals. Iron oxidation in the extracellular minerals was delayed by a few days compared with cell-associated Fe-minerals. This led to strong differences of Fe redox in between these two types of minerals and finally to local heterogeneities of redox within the sample. In the absence of dissolved Fe(II), vivianite was not significantly transformed by BoFeN1. Whereas Fe(II) oxidation at the cell contact is most probably directly catalyzed by the bacteria, vivianite transformation at a distance from the cells might result from oxidation by nitrite. In addition, processes leading to the export of Fe(III) from bacterial oxidation sites to extracellular minerals are discussed including some involving colloids observed by cryo-transmission electron microscopy in the culture medium. PMID:19573166

  13. Alteration of Iron-Rich Lacustrine Sediments by Dissimilatory Iron-Reducing Bacteria

    SciTech Connect

    Crowe,S.; Roberts, J.; Weisener, C.; Fowle, D.

    2007-01-01

    The reduction of Fe during bacterial anaerobic respiration in sediments and soils not only causes the degradation of organic matter but also results in changes in mineralogy and the redistribution of many nutrients and trace metals. Understanding trace metal patterns in sedimentary rocks and predicting the fate of contaminants in the environment requires a detailed understanding of the mechanisms through which they are redistributed during Fe reduction. In this work, lacustrine sediments from Lake Matano in Indonesia were incubated in a minimal media with the dissimilatory iron reducing (DIR) bacterium Shewanella putrefaciens 200R. These sediments were reductively dissolved at rates slower than pure synthetic goethite despite the presence of an 'easily reducible' component, as defined by selective extractions. DIR of the lacustrine sediments resulted in the substrate-dependent production of abundant quantities of extracellular polymeric substances. Trace elements, including Ni, Co, P, Si, and As, were released from the sediments with progressive Fe reduction while Cr was sequestered. Much of the initial trace metal mobility can be attributed to the rapid reduction of a Mn-rich oxyhydroxide phase. The production of organo-Fe(III) reveals that DIR bacteria can generate significant metal complexation capacity. This work demonstrates that DIR induces the release of many elements associated with Fe-Mn oxyhydroxides, despite secondary mineralization.

  14. Soil bioaugmentation by free and immobilized bacteria to reduce potentially phytoavailable cadmium.

    PubMed

    Jézéquel, Karine; Lebeau, Thierry

    2008-03-01

    Soil bioaugmentation was performed in soil pots to reduce the cadmium potentially available for plants. A Bacillus sp. (isolate ZAN-044) and a Streptomyces sp. (isolate R25) were compared, just as the inoculation technique, i.e., inoculum size, free or immobilized cells. After 3 weeks of a batch incubation, the potentially phytoavailable Cd was reduced, at the maximum, to a factor 14.1 and 4.3 with Bacillus sp. ZAN-044 and Streptomyces sp. R25, respectively. The two bacteria survived and colonized the soil. The immobilization technique did not improve the cell survival in the bioaugmented soil. The potentially phytoavailable Cd was positively (r(2)=+0.73) or negatively correlated (r(2)=-0.78) to the cell concentration in the sterilized soil bioaugmented with Bacillus sp. ZAN-044 or Streptomyces sp. R25, respectively. The major effect upon the phytoavailable Cd was the microorganism used and, to a lesser extent, the inoculum size and the culture technique. PMID:17379510

  15. Reducing bacteria and macrophage density on nanophase hydroxyapatite coated onto titanium surfaces without releasing pharmaceutical agents

    NASA Astrophysics Data System (ADS)

    Bhardwaj, Garima; Yazici, Hilal; Webster, Thomas J.

    2015-04-01

    Reducing bacterial density on titanium implant surfaces has been a major concern because of the increasing number of nosocomial infections. Controlling the inflammatory response post implantation has also been an important issue for medical devices due to the detrimental effects of chronic inflammation on device performance. It has recently been demonstrated that manipulating medical device surface properties including chemistry, roughness and wettability can control both infection and inflammation. Here, we synthesized nanophase (that is, materials with one dimension in the nanoscale) hydroxyapatite coatings on titanium to reduce bacterial adhesion and inflammatory responses (as measured by macrophage functions) and compared such results to bare titanium and plasma sprayed hydroxyapatite titanium coated surfaces used clinically today. This approach is a pharmaceutical-free approach to inhibit infection and inflammation due to the detrimental side effects of any drug released in the body. Here, nanophase hydroxyapatite was synthesized in sizes ranging from 110-170 nm and was subsequently coated onto titanium samples using electrophoretic deposition. Results indicated that smaller nanoscale hydroxyapatite features on titanium surfaces alone decreased bacterial attachment in the presence of gram negative (P. aeruginosa), gram positive (S. aureus) and ampicillin resistant gram-negative (E. coli) bacteria as well as were able to control inflammatory responses; properties which should lead to their further investigation for improved medical applications.

  16. DNA-SIP identifies sulfate-reducing Clostridia as important toluene degraders in tar-oil-contaminated aquifer sediment.

    PubMed

    Winderl, Christian; Penning, Holger; Netzer, Frederick von; Meckenstock, Rainer U; Lueders, Tillmann

    2010-10-01

    Global groundwater resources are constantly challenged by a multitude of contaminants such as aromatic hydrocarbons. Especially in anaerobic habitats, a large diversity of unrecognized microbial populations may be responsible for their degradation. Still, our present understanding of the respective microbiota and their ecophysiology is almost exclusively based on a small number of cultured organisms, mostly within the Proteobacteria. Here, by DNA-based stable isotope probing (SIP), we directly identified the most active sulfate-reducing toluene degraders in a diverse sedimentary microbial community originating from a tar-oil-contaminated aquifer at a former coal gasification plant. On incubation of fresh sediments with (13)C(7)-toluene, the production of both sulfide and (13)CO(2) was clearly coupled to the (13)C-labeling of DNA of microbes related to Desulfosporosinus spp. within the Peptococcaceae (Clostridia). The screening of labeled DNA fractions also suggested a novel benzylsuccinate synthase alpha-subunit (bssA) sequence type previously only detected in the environment to be tentatively affiliated with these degraders. However, carbon flow from the contaminant into degrader DNA was only ?50%, pointing toward high ratios of heterotrophic CO(2)-fixation during assimilation of acetyl-CoA originating from the contaminant by these degraders. These findings demonstrate that the importance of non-proteobacterial populations in anaerobic aromatics degradation, as well as their specific ecophysiology in the subsurface may still be largely ungrasped. PMID:20428224

  17. Novel Sulfated Polysaccharides Disrupt Cathelicidins, Inhibit RAGE and Reduce Cutaneous Inflammation in a Mouse Model of Rosacea

    PubMed Central

    Zhang, Jianxing; Xu, Xiaoyu; Rao, Narayanam V.; Argyle, Brian; McCoard, Lindsi; Rusho, William J.; Kennedy, Thomas P.; Prestwich, Glenn D.; Krueger, Gerald

    2011-01-01

    Background Rosacea is a common disfiguring skin disease of primarily Caucasians characterized by central erythema of the face, with telangiectatic blood vessels, papules and pustules, and can produce skin thickening, especially on the nose of men, creating rhinophyma. Rosacea can also produce dry, itchy eyes with irritation of the lids, keratitis and corneal scarring. The cause of rosacea has been proposed as over-production of the cationic cathelicidin peptide LL-37. Methodology/Principal Findings We tested a new class of non-anticoagulant sulfated anionic polysaccharides, semi-synthetic glycosaminoglycan ethers (SAGEs) on key elements of the pathogenic pathway leading to rosacea. SAGEs were anti-inflammatory at ng/ml, including inhibition of polymorphonuclear leukocyte (PMN) proteases, P-selectin, and interaction of the receptor for advanced glycation end-products (RAGE) with four representative ligands. SAGEs bound LL-37 and inhibited interleukin-8 production induced by LL-37 in cultured human keratinocytes. When mixed with LL-37 before injection, SAGEs prevented the erythema and PMN infiltration produced by direct intradermal injection of LL-37 into mouse skin. Topical application of a 1% (w/w) SAGE emollient to overlying injected skin also reduced erythema and PMN infiltration from intradermal LL-37. Conclusions Anionic polysaccharides, exemplified by SAGEs, offer potential as novel mechanism-based therapies for rosacea and by extension other LL-37-mediated and RAGE-ligand driven skin diseases. PMID:21347371

  18. Mtr Extracellular Electron Transfer Pathways in Fe(III)-reducing or Fe(II)-oxidizing Bacteria: A Genomic Perspective

    SciTech Connect

    Shi, Liang; Rosso, Kevin M.; Zachara, John M.; Fredrickson, Jim K.

    2012-12-01

    Originally discovered in the dissimilatory metal-reducing bacterium Shewanella oneidensis MR-1 (MR-1), the Mtr (i.e., metal-reducing) pathway exists in all characterized strains of metal-reducing Shewanella. The protein components identified to date for the Mtr pathway of MR-1 include four multi-heme c-type cytochromes (c-Cyts), CymA, MtrA, MtrC and OmcA, and a porin-like, outer membrane protein MtrB. They are strategically positioned along the width of the MR-1 cell envelope to mediate electron transfer from the quinone/quinol pool in the inner-membrane to the Fe(III)-containing minerals external to the bacterial cells. A survey of microbial genomes revealed homologues of the Mtr pathway in other dissimilatory Fe(III)-reducing bacteria, including Aeromonas hydrophila, Ferrimonas balearica and Rhodoferax ferrireducens, and in the Fe(II)-oxidizing bacteria Dechloromonas aromatica RCB, Gallionella capsiferriformans ES-2 and Sideroxydans lithotrophicus ES-1. The widespread distribution of Mtr pathways in Fe(III)-reducing or Fe(II)-oxidizing bacteria emphasizes the importance of this type of extracellular electron transfer pathway in microbial redox transformation of Fe. Their distribution in these two different functional groups of bacteria also emphasizes the bi-directional nature of electron transfer reactions carried out by the Mtr pathways. The characteristics of the Mtr pathways may be shared by other pathways used by microorganisms for exchanging electrons with their extracellular environments.

  19. Biofilm Dynamics and Kinetics during High-Rate Sulfate Reduction under Anaerobic Conditions

    PubMed Central

    Nielsen, Per Halkjaer

    1987-01-01

    The sulfate kinetics in an anaerobic, sulfate-reducing biofilm were investigated with an annular biofilm reactor. Biofilm growth, sulfide production, and kinetic constants (Km and Vmax) for the bacterial sulfate uptake within the biofilm were determined. These parameters were used to model the biofilm kinetics, and the experimental results were in good agreement with the model predictions. Typical zero-order volume rate constants for sulfate reduction in a biofilm without substrate limitation ranged from 56 to 93 ?mol of SO24-cm?3 h?1 at 20°C. The temperature dependence (Q10) of sulfate reduction was equivalent to 3.4 at between 9 and 20°C. The measured rates of sulfate reduction could explain the relatively high sulfide levels found in sewers and wastewater treatment systems. Furthermore, it has been shown that sulfate reduction in biofilms just a few hundred micrometers thick is limited by sulfate diffusion into biofilm at concentrations below 0.5 mM. This observation might, in some cases, be an explanation for the relatively poor capacity of the sulfate-reducing bacteria to compete with the methanogenic bacteria in anaerobic wastewater treatment in submerged filters. PMID:16347263

  20. 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). imilar results were obtained for enrichment cultures in which toluene was th...

  1. Sulfur and Carbon Isotope Systematics in Middle-Upper Cambrian Port au Port Group From Western Newfoundland, Canada: Implications for Seawater Sulfate Concentrations

    Microsoft Academic Search

    M. T. Hurtgen; S. Pruss; A. H. Knoll

    2006-01-01

    The biogeochemical cycles of carbon and sulfur are intimately linked through a variety of feedbacks that operate on timescales of days to millions of years. For example, under anaerobic conditions, some bacteria respire organic matter by sulfate reduction, reducing sulfate to sulfide, which then reacts with iron to form iron sulfide (preserved as pyrite). On much longer timescales, increases in

  2. Overview of Mercury Methylation Capacities among Anaerobic Bacteria Including Representatives of the Sulphate-Reducers: Implications for Environmental Studies

    Microsoft Academic Search

    M. Ranchou-Peyruse; M. Monperrus; R. Bridou; R. Duran; D. Amouroux; J. C. Salvado; R. Guyoneaud

    2009-01-01

    Mercury methylation has been extensively reported in the literature among “Firmicutes” and “Proteobacteria.” Nevertheless, results are hardly comparable because of differences in initial inorganic mercury concentrations used. The use of stable isotopic tracers now permits to study mercury transformations at concentrations close to environmental levels. Here, several strains, including strict fermentative and sulphate-reducing bacteria, were tested for their mercury methylation

  3. Use of Disinfectants and Cleaners to Reduce Bacteria on Poultry Transportation Coops with a Compressed Air Foam System

    E-print Network

    Hinojosa-Garza, Carolee A.

    2013-05-24

    and disinfect poultry transport coops. The objective of this study was to evaluate treatments consisting of a low-pressure water rinse (LPWR), a foaming additive alone, foaming cleaner or peroxyacetic acid with a foaming additive to reduce bacteria on broiler...

  4. Secondary mineral formation associated with respiration of nontronite, NAu-1 by iron reducing bacteria

    PubMed Central

    O'Reilly, S Erin; Watkins, Janet; Furukawa, Yoko

    2005-01-01

    Experimental batch and miscible-flow cultures were studied in order to determine the mechanistic pathways of microbial Fe(III) respiration in ferruginous smectite clay, NAu-1. The primary purpose was to resolve if alteration of smectite and release of Fe precedes microbial respiration. Alteration of NAu-1, represented by the morphological and mineralogical changes, occurred regardless of the extent of microbial Fe(III) reduction in all of our experimental systems, including those that contained heat-killed bacteria and those in which O2, rather than Fe(III), was the primary terminal electron acceptor. The solid alteration products observed under transmission electron microscopy included poorly crystalline smectite with diffuse electron diffraction signals, discrete grains of Fe-free amorphous aluminosilicate with increased Al/Si ratio, Fe-rich grains, and amorphous Si globules in the immediate vicinity of bacterial cells and extracellular polymeric substances. In reducing systems, Fe was also found as siderite. The small amount of Fe partitioned to the aqueous phase was primarily in the form of dissolved Fe(III) species even in the systems in which Fe(III) was the primary terminal electron acceptor for microbial respiration. From these observations, we conclude that microbial respiration of Fe(III) in our laboratory systems proceeded through the following: (1) alteration of NAu-1 and concurrent release of Fe(III) from the octahedral sheets of NAu-1; and (2) subsequent microbial respiration of Fe(III).

  5. [Influence of transition metal compounds on superoxide dismutase activity of sulfur reducing Desulfuromonas acetoxidans bacteria].

    PubMed

    Vasyliv, O M; Hnatush, S O

    2013-01-01

    Superoxide dismutase, as one of the enzymes of cells' antioxidant defensive system, catalyzes superoxide anion-radical (O2-) dismutation with O2 and H2O2 forming. The influence of such transition metal compounds, as FeSO4, FeCl3, MnCl2, NiCl2, and CoCl2 on superoxide dismutase activity of sulfur-reducing Desulfuromonas acetoxidans bacteria has been investigated. Maximal activity of the investigated enzyme has been observed accordingly under the influence of 1.0 mM of NiCl2, 2.0 mM of CoCl2 and MnCl2 on the second day and under the influence of 1.0 mM of FeCl3 and FeSO4 respectively, on the third day of growth in comparison with control samples. An increase of incubation time and concentration of metal compound in the medium caused the inhibition of superoxide dismutase activity. PMID:23720962

  6. Rapid and Simple Method for the Most-Probable-Number Estimation of Arsenic-Reducing Bacteria

    PubMed Central

    Kuai, Linping; Nair, Arjun A.; Polz, Martin F.

    2001-01-01

    A rapid and simple most-probable-number (MPN) procedure for the enumeration of dissimilatory arsenic-reducing bacteria (DARB) is presented. The method is based on the specific detection of arsenite, the end product of anaerobic arsenate respiration, by a precipitation reaction with sulfide. After 4 weeks of incubation, the medium for the MPN method is acidified to pH 6 and sulfide is added to a final concentration of about 1 mM. The brightly yellow arsenic trisulfide precipitates immediately and can easily be scored at arsenite concentrations as low as 0.05 mM. Abiotic reduction of arsenate upon sulfide addition, which could yield false positives, apparently produces a soluble As-S intermediate, which does not precipitate until about 1 h after sulfide addition. Using the new MPN method, population estimates of pure cultures of DARB were similar to direct cell counts. MPNs of environmental water and sediment samples yielded DARB numbers between 101 and 105 cells per ml or gram (dry weight), respectively. Poisoned and sterilized controls showed that potential abiotic reductants in environmental samples did not interfere with the MPN estimates. A major advantage is that the assay can be easily scaled to a microtiter plate format, enabling analysis of large numbers of samples by use of multichannel pipettors. Overall, the MPN method provides a rapid and simple means for estimating population sizes of DARB, a diverse group of organisms for which no comprehensive molecular markers have been developed yet. PMID:11425737

  7. Isolation and Characterization of Chromium(VI)-Reducing Bacteria from Tannery Effluents.

    PubMed

    Ilias, Mohammad; Rafiqullah, Iftekhar Md; Debnath, Bejoy Chandra; Mannan, Khanjada Shahnewaj Bin; Mozammel Hoq, Md

    2011-01-01

    Two chromium-resistant bacteria (IFR-2 and IFR-3) capable of reducing/transforming Cr(VI) to Cr(III) were isolated from tannery effluents. Isolates IFR-2 and IFR-3 were identified as Staphylococcus aureus and Pediococcus pentosaceus respectively by 16S rRNA gene sequence analyses. Both isolates can grow well on 2,000 mg/l Cr(VI) (as K(2)Cr(2)O(7)) in Luria-Bertani (LB) medium. Reduction of Cr(VI) was found to be growth-associated in both isolates and IFR-2 and IFR-3 reduced 20 mg/l Cr(VI) completely in 6 and 24 h respectively. The Cr(VI) reduction due to chromate reductase activity was detected in the culture supernatant and cell lysate but not at all in the cell extract supernatant of both isolates. Whole cells of IFR-2 and IFR-3 converted 24 and 30% of the initial Cr(VI) concentration (1 mg/l) in 45 min respectively at 37°C. NiCl(2) stimulated the growth of IFR-2 whereas HgCl(2) and CdCl(2) significantly inhibited the growth of both isolates. Optimum temperature and pH for growth of and Cr(VI) reduction by both isolates were found to be between 35 and 40°C and pH 7.0 to 8.0. The two bacterial isolates can be good candidates for detoxification of Cr(VI) in industrial effluents. PMID:22282632

  8. EXPERIMENTAL CHLORATE PRODUCT TREATMENT TO REDUCE FOOD BORNE PATHOGENIC BACTERIA IN RUMINANT AND MONOGASTRIC FOOD ANIMALS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pathogenic bacteria that cause human food borne illness can live within the gastrointestinal tract of food animals. Many of these bacteria do not affect animal production, but do pose a threat to consumers via meat and dairy products. Over 76 million cases of food borne illness occur each year in ...

  9. SMALL PLANT INTERVENTION TREATMENTS TO REDUCE BACTERIA ON BEEF CARCASSES AT SLAUGHTER

    Microsoft Academic Search

    DENNIS BUEGE; STEVE INGHAM

    2003-01-01

    The slaughter process for cattle and other meat-producing animals involves the removal of the bacteria- free meat from between two contaminated surfaces - the hide and the GI tract. In this process, no matter how carefully it is carried out, there will invariably be transfer of bacteria to the carcass. The food safety goal of the slaughter process is minimize

  10. Sugar utilization in the hyperthermophilic, sulfate-reducing archaeon Archaeoglobus fulgidus strain 7324: starch degradation to acetate and CO 2 via a modified Embden-Meyerhof pathway and acetylCoA synthetase (ADP-forming)

    Microsoft Academic Search

    Antje Labes; Peter Schönheit

    2001-01-01

    The hyperthermophilic, sulfate-reducing archaeon Archaeoglobus fulgidus strain 7324, rather than the type strain VC16, was found to grow on starch and sulfate as energy and carbon source. Fermentation products and enzyme activities were determined in starch-grown cells and compared to those of cells grown on lactate and sulfate. During exponential growth on starch, 1 mol of glucose-equivalent was incompletely oxidized

  11. Plant-associated bacteria degrade defense chemicals and reduce their adverse effects on an insect defoliator.

    PubMed

    Mason, Charles J; Couture, John J; Raffa, Kenneth F

    2014-07-01

    Phytophagous insects must contend with numerous secondary defense compounds that can adversely affect their growth and development. The gypsy moth (Lymantria dispar) is a polyphagous herbivore that encounters an extensive range of hosts and chemicals. We used this folivore and a primary component of aspen chemical defenses, namely, phenolic glycosides, to investigate if bacteria detoxify phytochemicals and benefit larvae. We conducted insect bioassays using bacteria enriched from environmental samples, analyses of the microbial community in the midguts of bioassay larvae, and in vitro phenolic glycoside metabolism assays. Inoculation with bacteria enhanced larval growth in the presence, but not absence, of phenolic glycosides in the artificial diet. This effect of bacteria on growth was observed only in larvae administered bacteria from aspen foliage. The resulting midgut community composition varied among the bacterial treatments. When phenolic glycosides were included in diet, the composition of midguts in larvae fed aspen bacteria was significantly altered. Phenolic glycosides increased population responses by bacteria that we found able to metabolize these compounds in liquid growth cultures. Several aspects of these results suggest that vectoring or pairwise symbiosis models are inadequate for understanding microbial mediation of plant-herbivore interactions in some systems. First, bacteria that most benefitted larvae were initially foliar residents, suggesting that toxin-degrading abilities of phyllosphere inhabitants indirectly benefit herbivores upon ingestion. Second, assays with single bacteria did not confer the benefits to larvae obtained with consortia, suggesting multi- and inter-microbial interactions are also involved. Our results show that bacteria mediate insect interactions with plant defenses but that these interactions are community specific and highly complex. PMID:24798201

  12. Glucosamine sulfate

    MedlinePLUS

    ... Sulphate, Glucosamine Sulphate KCl, Glucosamine-6-Phosphate, GS, Mono-Sulfated Saccharide, Poly-(1->3)-N-Acetyl-2- ... Beta-D-Glucopyranurosyl-4-(or 6-) Sul, Saccharide Mono-Sulfaté, Saccharide Sulfaté, Sulfate de Glucosamine, Sulfate de ...

  13. Sulfate but Not Thiosulfate Reduces Calculated and Measured Urinary Ionized Calcium and Supersaturation: Implications for the Treatment of Calcium Renal Stones

    PubMed Central

    Rodgers, Allen; Gauvin, Daniel; Edeh, Samuel; Allie-Hamdulay, Shameez; Jackson, Graham; Lieske, John C.

    2014-01-01

    Background Urinary sulfate (SO42?) and thiosulfate (S2O32?) can potentially bind with calcium and decrease kidney stone risk. We modeled the effects of these species on the concentration of ionized calcium (iCa) and on supersaturation (SS) of calcium oxalate (CaOx) and calcium phosphate (CaP), and measured their in vitro effects on iCa and the upper limit of stability (ULM) of these salts. Methods Urine data from 4 different types of stone patients were obtained from the Mayo Nephrology Clinic (Model 1). A second data set was obtained from healthy controls and hypercalciuric stone formers in the literature who had been treated with sodium thiosulfate (STS) (Model 2). The Joint Expert Speciation System (JESS) was used to calculate iCa and SS. In Model 1, these parameters were calculated as a function of sulfate and thiosulfate concentrations. In Model 2, data from pre- and post STS urines were analyzed. ULM and iCa were determined in human urine as a function of sulfate and thiosulfate concentrations. Results Calculated iCa and SS values for all calcium salts decreased with increasing sulfate concentration. Thiosulfate had no effect on these parameters. In Model 2, calculated iCa and CaOx SS increased after STS treatment, but CaP SS decreased, perhaps due to a decrease in pH after STS treatment. In confirmatory in vitro experiments supplemental sulfate, but not thiosulfate, significantly increased the calcium needed to achieve the ULM of CaP and tended to increase the oxalate needed to reach the ULM of CaOx. Sulfate also significantly decreased iCa in human urine, while thiosulfate had no effect. Conclusion Increasing urinary sulfate could theoretically reduce CaOx and CaP stone risk. Although STS may reduce CaP stone risk by decreasing urinary pH, it might also paradoxically increase iCa and CaOx SS. As such, STS may not be a viable treatment option for stone disease. PMID:25061988

  14. Trinitrotoluene (TNT) as a sole nitrogen source for a sulfate-reducing bacterium Desulfovibrio sp. (B strain) isolated from an anaerobic digester

    Microsoft Academic Search

    R. Boopathy; C. F. Kulpa

    1992-01-01

    A sulfate-reducing bacterium (SRB),Desulfovibrio sp. (B strain), isolated from a continuous anaerobic digester (Boopathy and Daniels, Current Microbiology, 23:327–332, 1991) was found to use 2,4,6-trinitrotoluene (TNT) as sole nitrogen source. This bacterium also used nitrate, nitrite, and ammonium as nitrogen source. A long lag period was noticed when TNT or nitrite was used as nitrogen source. Nitrate, nitrite and TNT

  15. Mercury Methylation from Unexpected Sources: Molybdate-Inhibited Freshwater Sediments and an Iron-Reducing Bacterium

    Microsoft Academic Search

    Emily J. Fleming; E. Erin Mack; Peter G. Green; Douglas C. Nelson

    2006-01-01

    Methylmercury has been thought to be produced predominantly by sulfate-reducing bacteria in anoxic sediments. Here we show that in circumneutral pH sediments (Clear Lake, CA) application of a specific inhibitor of sulfate-reducing bacteria at appropriate concentrations typically inhibited less than one-half of all anaerobic methylation of added divalent mercury. This suggests that one or more additional groups of microbes are

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

    EPA Science Inventory

    A proposed novel method for treatment of acid mine drainage (AMD) waste uses biologically-generated hydrogen sulfide to precipitate the metals in AMD (principally zinc, iron, aluminum, copper and manganese in the Berkeley Pit). The solids are sequentially removed via settling. ...

  17. Activity, Distribution, and Diversity of Sulfate Reducers and Other Bacteria in Sediments above Gas Hydrate (Cascadia Margin, Oregon)

    Microsoft Academic Search

    Katrin Knittel; Antje Boetius; Andreas Lemke; Heike Eilers; Karin Lochte; Olaf Pfannkuche; Peter Linke; Rudolf Amann

    2003-01-01

    Cold seep environments such as sediments above outcropping hydrate at Hydrate Ridge (Cascadia margin off Oregon) are characterized by methane venting, high sulfide fluxes caused by the anaerobic oxidation of methane, and the presence of chemosynthetic communities. Recent investigations showed that another characteristic feature of cold seeps is the occurrence of methanotrophic archaea, which can be identified by specific biomarker

  18. Transformation, localization, and biomolecular binding of Hg species at subcellular level in methylating and nonmethylating sulfate-reducing bacteria.

    PubMed

    Pedrero, Zoyne; Bridou, Romain; Mounicou, Sandra; Guyoneaud, Remy; Monperrus, Mathilde; Amouroux, David

    2012-11-01

    Microbial activity is recognized to play an important role on Hg methylation in aquatic ecosystems. However, the mechanism at the cellular level is still poorly understood. In this work subcellular partitioning and transformation of Hg species in two strains: Desulfovibrio sp. BerOc1 and Desulfovibrio desulfuricans G200 (which exhibit different Hg methylation potential) are studied as an approach to the elucidation of Hg methylation/demethylation processes. The incubation with isotopically labeled Hg species ((199)Hgi and Me(201)Hg) not only allows the determination of methylation and demethylation rates simultaneously, but also the comparison of the localization of the originally added and resulting species of such metabolic processes. A dissimilar Hg species distribution was observed. In general terms, monomethylmercury (MeHg) is preferentially localized in the extracellular fraction; meanwhile inorganic mercury (Hgi) is associated to the cells. The investigation of Hg binding biomolecules on the cytoplasmatic and extracellular fractions (size exclusion chromatography coupled to ICP-MS) revealed noticeable differences in the pattern corresponding to the Hg methylating and nonmethylating strains. PMID:23050725

  19. Novel quaternary ammonium hydroxide cationic surfactants as corrosion inhibitors for carbon steel and as biocides for sulfate reducing bacteria (SRB)

    Microsoft Academic Search

    A. M. Badawi; M. A. Hegazy; A. A. El-Sawy; H. M. Ahmed; W. M. Kamel

    2010-01-01

    A series of alkyl dimethylisopropylammonium hydroxide cationic surfactants (DEDIAOH, DODIAOH and HEDIAOH) was synthesized and characterized. The surface properties such as the critical micelle concentration (CMC), the effectiveness of surface tension reduction (?CMC), surface excess concentration (?max) and surface area per molecule (Amin) have been determined by means of surface tension measurements. The degree of counter ion dissociation (?) and

  20. Biological pre-treatment of wastewater containing sulfate using anaerobic immobilized cells

    Microsoft Academic Search

    Wen-Chien Kuo; Tzu-Yueh Shu

    2004-01-01

    Biological reduction of sulfate to sulfide using sulfate reducing bacteria (SRB) was investigated. A respirometer was used to study the sulfide toxicity in the systems fed glucose, the results showed that sulfide would start to inhibit methanogens when the dissolved sulfide and total sulfide concentrations were 276.4 and 304.6mg\\/L, respectively. When chemostats were used to study the Monod kinetic coefficients,

  1. Using Sulfate-Amended Sediment Slurry Batch Reactors to Evaluate Mercury Methylation

    Microsoft Academic Search

    S. M. Harmon; J. K. King; J. B. Gladden; L. A. Newman

    2007-01-01

    In the methylated form, mercury represents a concern to public health primarily through the consumption of contaminated fish\\u000a tissue. Research conducted on the methylation of mercury strongly suggests that the process is microbial in nature and facilitated\\u000a principally by sulfate-reducing bacteria. This study addressed the potential for mercury methylation by varying sulfate treatments\\u000a and wetland-based soil in microbial slurry reactors

  2. Microbial fouling community analysis of the cooling water system of a nuclear test reactor with emphasis on sulphate reducing bacteria.

    PubMed

    Balamurugan, P; Joshi, M Hiren; Rao, T S

    2011-10-01

    Culture and molecular-based techniques were used to characterize bacterial diversity in the cooling water system of a fast breeder test reactor (FBTR). Techniques were selected for special emphasis on sulphate-reducing bacteria (SRB). Water samples from different locations of the FBTR cooling water system, in addition to biofilm scrapings from carbon steel coupons and a control SRB sample were characterized. Whole genome extraction of the water samples and SRB diversity by group specific primers were analysed using nested PCR and denaturing gradient gel electrophoresis (DGGE). The results of the bacterial assay in the cooling water showed that the total culturable bacteria (TCB) ranged from 10(3) to 10(5) cfu ml(-1); iron-reducing bacteria, 10(3) to 10(5) cfu ml(-1); iron oxidizing bacteria, 10(2) to 10(3) cfu ml(-1) and SRB, 2-29 cfu ml(-1). However, the counts of the various bacterial types in the biofilm sample were 2-3 orders of magnitude higher. SRB diversity by the nested PCR-DGGE approach showed the presence of groups 1, 5 and 6 in the FBTR cooling water system; however, groups 2, 3 and 4 were not detected. The study demonstrated that the PCR protocol influenced the results of the diversity analysis. The paper further discusses the microbiota of the cooling water system and its relevance in biofouling. PMID:21929472

  3. Phylogenetic diversity of methanogenic, sulfate-reducing and methanotrophic prokaryotes from deep-sea hydrothermal vents and cold seeps

    NASA Astrophysics Data System (ADS)

    Reed, Andrew J.; Dorn, Ruth; Van Dover, Cindy L.; Lutz, Richard A.; Vetriani, Costantino

    2009-09-01

    Microbial communities of methanogenic, sulfate-reducing and methanotrophic prokaryotes from deep-sea environments were investigated by molecular phylogenetic analysis of the deduced amino acid sequences of the genes encoding for the methyl coenzyme M reductase ( mcrA), dissimilatory sulfite reductase ( dsrAB) and particulate methane monoxygenase ( pmoA), respectively. Clone libraries of PCR amplified genes were constructed using DNA extracted from deep-sea vent chimneys (Rainbow and Logatchev hydrothermal vent fields, Mid-Atlantic Ridge, Atlantic Ocean; 9°N East Pacific Rise, Pacific Ocean) and from vertically subsampled sediment cores from cold-seep areas (Blake Ridge, western Atlantic Ocean; Florida Escarpment, Gulf of Mexico). Recombinant clones were screened by RFLP and representative dsrAB, mcrA and pmoA genes were sequenced. The dsrAB sequences grouped primarily within the orders Desulfobacterales, Syntrophobacterales and the Gram-positive order Clostridales. Cold-seep mcrA sequences were distributed among the ANME-2c, -2d and -2e groups, which were previously shown to be associated with the anaerobic oxidation of methane. This study also reports the first mcrA sequences from a high-temperature, black smoker chimney (Logatchev) to group within the ANME-2e subgroup. The majority of the remaining hydrothermal vent mcrA sequences were primarily related to thermophilic members of the anaerobic, methanogenic order Methanococcales. A shift in the dominant ANME-2 group with depth in the sediment for both Florida Escarpment and Blake Ridge mcrA libraries was detected. ANME-2d related clones were detected in the top zones of both cores, with the frequency of ANME-2e related clones increasing with depth. All pmoA sequences retrieved from the cold-seep sites were found to be related to Type I methanotrophic members of the ?-proteobacteria, and were primarily distributed among three major clusters of sequences. No Type II pmoA sequences related to methanotrophic members of the ?-proteobacteria were detected, suggesting that the methanotrophic communities in these cold-seep areas are dominated by Type I ?-proteobacteria.

  4. Desulfovibrio carbinoliphilus sp. nov., a benzyl alcohol-oxidizing, sulfate-reducing bacterium isolated from a gas condensate-contaminated aquifer.

    PubMed

    Allen, Toby D; Kraus, Paul F; Lawson, Paul A; Drake, Gwendolyn R; Balkwill, David L; Tanner, Ralph S

    2008-06-01

    Phenotypic and phylogenetic studies were performed on a novel sulfate-reducing bacterium, strain D41(T), isolated as part of a methanogenic syntrophic culture from a gas condensate-contaminated aquifer undergoing intrinsic bioremediation. The bacterium was a Gram-negative, non-spore-forming, curved rod, motile by a single polar flagellum, which oxidized several alcohols incompletely, including methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 3-methyl-1-butanol (isoamyl alcohol), ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, phenylethanol and benzyl alcohol. Additionally, the strain oxidized H(2)/CO(2), formate, lactate, pyruvate, maleate, malate and fumarate. Sulfate, thiosulfate and sulfite were used as electron acceptors. The DNA G+C content was 63 mol%. Based on phylogenetic and phenotypic evidence, the novel species Desulfovibrio carbinoliphilus sp. nov. is proposed. The type strain is D41(T) (=ATCC BAA-1241(T) =DSM 17524(T)). PMID:18523171

  5. Diversity and identification of methanogenic archaea and sulphate-reducing bacteria in sediments from a pristine tropical mangrove

    Microsoft Academic Search

    Rodrigo Gouvêa Taketani; Caio Augusto Yoshiura; Armando Cavalcante Franco Dias; Fernando Dini Andreote; Siu Mui Tsai

    2010-01-01

    Mangrove sediments are anaerobic ecosystems rich in organic matter. This environment is optimal for anaerobic microorganisms,\\u000a such as sulphate-reducing bacteria and methanogenic archaea, which are responsible for nutrient cycling. In this study, the\\u000a diversity of these two functional guilds was evaluated in a pristine mangrove forest using denaturing gradient gel electrophoresis\\u000a (DGGE) and clone library sequencing in a 50 cm vertical

  6. Diversity of Ferrous Iron-Oxidizing, Nitrate-Reducing Bacteria and their Involvement in Oxygen-Independent Iron Cycling

    Microsoft Academic Search

    Kristina L. Straub; Wilhelm A. Schönhuber; Berit E. E. Buchholz-Cleven; Bernhard Schink

    2004-01-01

    In previous studies, three different strains (BrG1, BrG2, and BrG3) of ferrous iron-oxidizing, nitrate-reducing bacteria were obtained from freshwater sediments. All three strains were facultative anaerobes and utilized a variety of organic substrates and molecular hydrogen with nitrate as electron acceptor. In this study, analyses of 16S rDNA sequences showed that strain BrG1 was affiliated with the genus Acidovorax, strain

  7. Evidence for equilibrium iron isotope fractionation by nitrate-reducing iron(II)-oxidizing bacteria

    PubMed Central

    Kappler, A.; Johnson, C.M.; Crosby, H.A.; Beard, B.L.; Newman, D.K.

    2010-01-01

    Iron isotope fractionations produced during chemical and biological Fe(II) oxidation are sensitive to the proportions and nature of dissolved and solid-phase Fe species present, as well as the extent of isotopic exchange between precipitates and aqueous Fe. Iron isotopes therefore potentially constrain the mechanisms and pathways of Fe redox transformations in modern and ancient environments. In the present study, we followed in batch experiments Fe isotope fractionations between Fe(II)aq and Fe(III) oxide/hydroxide precipitates produced by the Fe(III) mineral encrusting, nitrate-reducing, Fe(II)-oxidizing Acidovorax sp. strain BoFeN1. Isotopic fractionation in 56Fe/54Fe approached that expected for equilibrium conditions, assuming an equilibrium ?56FeFe(OH)3 – Fe(II)aq fractionation factor of +3.0 ‰. Previous studies have shown that Fe(II) oxidation by this Acidovorax strain occurs in the periplasm, and we propose that Fe isotope equilibrium is maintained through redox cycling via coupled electron and atom exchange between Fe(II)aq and Fe(III) precipitates in the contained environment of the periplasm. In addition to the apparent equilibrium isotopic fractionation, these experiments also record the kinetic effects of initial rapid oxidation, and possible phase transformations of the Fe(III) precipitates. Attainment of Fe isotope equilibrium between Fe(III) oxide/hydroxide precipitates and Fe(II)aq by neutrophilic, Fe(II)-oxidizing bacteria or through abiologic Fe(II)aq oxidation is generally not expected or observed, because the poor solubility of their metabolic product, i.e. Fe(III), usually leads to rapid precipitation of Fe(III) minerals, and hence expression of a kinetic fractionation upon precipitation; in the absence of redox cycling between Fe(II)aq and precipitate, kinetic isotope fractionations are likely to be retained. These results highlight the distinct Fe isotope fractionations that are produced by different pathways of biological and abiological Fe(II) oxidation. PMID:21076519

  8. Evidence for equilibrium iron isotope fractionation by nitrate-reducing iron(II)-oxidizing bacteria.

    PubMed

    Kappler, A; Johnson, C M; Crosby, H A; Beard, B L; Newman, D K

    2010-05-10

    Iron isotope fractionations produced during chemical and biological Fe(II) oxidation are sensitive to the proportions and nature of dissolved and solid-phase Fe species present, as well as the extent of isotopic exchange between precipitates and aqueous Fe. Iron isotopes therefore potentially constrain the mechanisms and pathways of Fe redox transformations in modern and ancient environments. In the present study, we followed in batch experiments Fe isotope fractionations between Fe(II)(aq) and Fe(III) oxide/hydroxide precipitates produced by the Fe(III) mineral encrusting, nitrate-reducing, Fe(II)-oxidizing Acidovorax sp. strain BoFeN1. Isotopic fractionation in (56)Fe/(54)Fe approached that expected for equilibrium conditions, assuming an equilibrium ?(56)Fe(Fe(OH)3 - Fe(II)aq) fractionation factor of +3.0 ‰. Previous studies have shown that Fe(II) oxidation by this Acidovorax strain occurs in the periplasm, and we propose that Fe isotope equilibrium is maintained through redox cycling via coupled electron and atom exchange between Fe(II)(aq) and Fe(III) precipitates in the contained environment of the periplasm. In addition to the apparent equilibrium isotopic fractionation, these experiments also record the kinetic effects of initial rapid oxidation, and possible phase transformations of the Fe(III) precipitates. Attainment of Fe isotope equilibrium between Fe(III) oxide/hydroxide precipitates and Fe(II)(aq) by neutrophilic, Fe(II)-oxidizing bacteria or through abiologic Fe(II)(aq) oxidation is generally not expected or observed, because the poor solubility of their metabolic product, i.e. Fe(III), usually leads to rapid precipitation of Fe(III) minerals, and hence expression of a kinetic fractionation upon precipitation; in the absence of redox cycling between Fe(II)(aq) and precipitate, kinetic isotope fractionations are likely to be retained. These results highlight the distinct Fe isotope fractionations that are produced by different pathways of biological and abiological Fe(II) oxidation. PMID:21076519

  9. On-farm interventions to reduce epizootic bacteria in food-producing animals and the environment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Food producing animals can be reservoirs of human pathogenic bacteria such as enterohemorrhagic Escherichia coli (O157- and non-O157 Shigatoxin-producing E. coli), Salmonella, and Campylobacter, often harboring these pathogens within their gastrointestinal tracts. Carrier animals colonized by these...

  10. Iron-reducing bacteria unravel novel strategies for the anaerobic catabolism of aromatic compounds

    Microsoft Academic Search

    Manuel Carmona; Eduardo Díaz

    2005-01-01

    Summary Although the aerobic degradation of aromatic com- pounds has been extensively studied in many microorganisms, the anaerobic mineralization of the aromatic ring is a more recently discovered microbial capacity on which very little information is available from facultative anaerobic bacteria. In this issue of Molecular Microbiology , Wischgoll and colleagues use proteomic and reverse-transcription polymerase chain reaction (PCR) approaches

  11. Intestinal dysbiosis and reduced immunoglobulin-coated bacteria associated with coeliac disease in children

    Microsoft Academic Search

    Giada De Palma; Inmaculada Nadal; Marcela Medina; Ester Donat; Carmen Ribes-Koninckx; Miguel Calabuig; Yolanda Sanz

    2010-01-01

    BACKGROUND: Coeliac disease is a chronic intestinal inflammatory disorder due to an aberrant immune response to dietary gluten proteins in genetically predisposed individuals. Mucosal immune response through IgA secretion constitutes a first line of defence responsible for neutralizing noxious antigens and pathogens. The aim of this study was the characterization of the relationships between immunoglobulin-coated bacteria and bacterial composition of

  12. Desulfovirga adipica gen. nov., sp. nov., an adipate-degrading, Gram-negative, sulfate-reducing bacterium

    Microsoft Academic Search

    Kazuhiro Tanaka; Erko Stackebrandt; Shigehiro Tohyama; Tadashi Eguchi

    A novel, mesophilic, Gram-negative bacterium was isolated from an anaerobic digestor for municipal wastewater. The bacterium degraded adipate in the presence of sulfate, sulfite, thiosulfate and elemental sulfur. (E)-2- Hexenedioate accumulated transiently in the degradation of adipate. (E)-2- Hexenedioate, (E)-3-hexenedioate, pyruvate, lactate, C1-C12 straight-chain fatty acids and C2-C10 straight-chain primary alcohols were also utilized as electron donors. 3-Phenylpropionate was oxidized

  13. Effect of Sodium Nitrate and Nitrate Reducing Bacteria on In vitro Methane Production and Fermentation with Buffalo Rumen Liquor.

    PubMed

    Sakthivel, Pillanatham Civalingam; Kamra, Devki Nandan; Agarwal, Neeta; Chaudhary, Lal Chandra

    2012-06-01

    Nitrate can serve as a terminal electron acceptor in place of carbon dioxide and inhibit methane emission in the rumen and nitrate reducing bacteria might help enhance the reduction of nitrate/nitrite, which depends on the type of feed offered to animals. In this study the effects of three levels of sodium nitrate (0, 5, 10 mM) on fermentation of three diets varying in their wheat straw to concentrate ratio (700:300, low concentrate, LC; 500:500, medium concentrate, MC and 300:700, high concentrate, HC diet) were investigated in vitro using buffalo rumen liquor as inoculum. Nitrate reducing bacteria, isolated from the rumen of buffalo were tested as a probiotic to study if it could help in enhancing methane inhibition in vitro. Inclusion of sodium nitrate at 5 or 10 mM reduced (p<0.01) methane production (9.56, 7.93 vs. 21.76 ml/g DM; 12.20, 10.42 vs. 25.76 ml/g DM; 15.49, 12.33 vs. 26.86 ml/g DM) in LC, MC and HC diets, respectively. Inclusion of nitrate at both 5 and 10 mM also reduced (p<0.01) gas production in all the diets, but in vitro true digestibility (IVTD) of feed reduced (p<0.05) only in LC and MC diets. In the medium at 10 mM sodium nitrate level, there was 0.76 to 1.18 mM of residual nitrate and nitrite (p<0.01) also accumulated. In an attempt to eliminate residual nitrate and nitrite in the medium, the nitrate reducing bacteria were isolated from buffalo adapted to nitrate feeding and introduced individually (3 ml containing 1.2 to 2.3×10(6) cfu/ml) into in vitro incubations containing the MC diet with 10 mM sodium nitrate. Addition of live culture of NRBB 57 resulted in complete removal of nitrate and nitrite from the medium with a further reduction in methane and no effect on IVTD compared to the control treatments containing nitrate with autoclaved cultures or nitrate without any culture. The data revealed that nitrate reducing bacteria can be used as probiotic to prevent the accumulation of nitrite when sodium nitrate is used to reduce in vitro methane emissions. PMID:25049631

  14. Attempts to reduce exposure to fungi, ?-glucan, bacteria, endotoxin and dust in vegetable greenhouses and a packaging unit.

    PubMed

    Madsen, Anne Mette; Tendal, Kira; Frederiksen, Margit W

    2014-01-15

    Indoor handling of large amounts of plant materials occurs in different occupational settings including greenhouses and causes exposure to bioaerosols. The bioaerosol components fungi, ?-glucan, bacteria and endotoxin are involved in different airway symptoms and health effects can be dose-dependent. Therefore, there is a persistent need to reduce exposure. The aims of this study were to identify tasks causing exposure and to evaluate preventive measures aimed at reducing exposure of greenhouse workers to bioaerosols, and to study factors affecting the exposure. We have focused on different exposure scenarios; one with high short-term exposure found during clearing of old cucumber plants; the other with long-term, mid-level exposure found during tomato picking, leaf nipping, stringing up tomato plants, and packaging of cucumbers. Clearing of non-dried cucumber plants compared with clearing of dried cucumber plants significantly reduced the exposure to dust, endotoxin, bacteria, fungal spores and ?-glucan. More endotoxin and fungi are emitted and more of the emitted particles were of respirable size if the leaves were dried. Along the cucumber packaging line, exposure levels were highly specific to each personal subtask. The subtask 'unloading of cucumbers' was the source of exposure making task ventilation or shielding of the process a possibility. Elimination of leaf debris on the floor reduced the exposure to fungi significantly. However, leaf debris on the floor did not contribute significantly to the exposure to dust, endotoxin and bacteria. Furthermore, to eliminate leaf debris, it had to be cleared away and this was associated with a higher exposure to dust and endotoxin. The age of the plants affected the exposure level to bioaerosols with higher exposures from old plants. In conclusion, different tasks and subtasks cause very different exposure levels. It is possible to reduce exposure by identifying subtasks causing the exposure and by modifying work processes, e.g., not drying out of plants. PMID:24112965

  15. Transport of bacteria in aquifer sediment: experiments and modeling

    Microsoft Academic Search

    Dong Ding

    2010-01-01

    A mathematical model based on the advection-dispersion equation, modified to account for growth, decay, attachment, and detachment\\u000a of microorganisms, was developed to describe the transport and growth of bacteria in aquifers. Column experiments on the transport\\u000a of a species of sulfate-reducing bacteria through saturated-aquifer sediment were conducted to gain a quantitative knowledge\\u000a of the attachment and detachment processes. Relevant parameter

  16. Isolation and characterization of Desulfocurvus thunnarius sp. nov., a sulfate-reducing bacterium isolated from an anaerobic sequencing batch reactor treating cooking wastewater.

    PubMed

    Hamdi, Olfa; Ben Hania, Wajdi; Postec, Anne; Bartoli, Manon; Hamdi, Moktar; Bouallagui, Hassib; Fauque, Guy; Ollivier, Bernard; Fardeau, Marie-Laure

    2013-11-01

    A novel anaerobic, chemo-organotrophic, sulfate-reducing bacterium, designated strain Olac 40(T), was isolated from a Tunisian wastewater digestor. Cells were curved, motile rods or vibrios (5.0-7.0×0.5 µm). Strain Olac 40(T) grew at temperatures between 15 and 50 °C (optimum 40 °C), and between pH 5.0 and 9.0 (optimum pH 7.1). It did not require NaCl for growth but tolerated it up to 50 g l(-1) (optimum 2 g l(-1)). In the presence of sulfate or thiosulfate, strain Olac 40(T) used lactate, pyruvate and formate as energy sources. Growth was observed on H2 only in the presence of acetate as carbon source. In the presence of sulfate or thiosulfate, the end products of lactate oxidation were acetate, sulfide and CO2. Sulfate, thiosulfate and sulfite were used as terminal electron acceptors, but not elemental sulfur, nitrate or nitrite. The genomic DNA G+C content of strain Olac 40(T) was 70 mol%. The profile of polar lipids consisted of phosphatidylglycerol, phosphatidylethanolamine, aminophospholipid and four phospholipids. The main fatty acids were C16?:?0, anteiso-C15?:?0 and iso-C15?:?0. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain Olac 40(T) was affiliated with the family Desulfovibrionaceae within the class Deltaproteobacteria. On the basis of 16S rRNA gene sequence comparisons and physiological characteristics, strain Olac 40(T) is proposed to be assigned to a novel species of the genus Desulfocurvus, for which the name Desulfocurvus thunnarius is proposed. The type strain is Olac 40(T) (?=?DSM 26129(T)?=?JCM 18546(T)). PMID:23811135

  17. Interactions of microbes in aquatic systems Uncultured populations of bacteria were analyzed in aquatic systems and populations related

    E-print Network

    Aspbury, Andrea S. - Department of Biology, Texas State University

    Interactions of microbes in aquatic systems Uncultured populations of bacteria were analyzed, these studies dealt with the qualitative and quantitative analysis of Archaea in anaerobic sediments of Lake-forming phototrophic sulfur and sulfate-reducing bacteria in the chemocline of the meromictic Lake Cadagno, Switzerland

  18. Bacterial enzymes for dissimilatory sulfate reduction in a marine microbial mat (Black Sea) mediating anaerobic oxidation of methane.

    PubMed

    Basen, Mirko; Krüger, Martin; Milucka, Jana; Kuever, Jan; Kahnt, Jörg; Grundmann, Olav; Meyerdierks, Anke; Widdel, Friedrich; Shima, Seigo

    2011-05-01

    Anaerobic oxidation of methane (AOM) with sulfate is catalysed by microbial consortia of archaea and bacteria affiliating with methanogens and sulfate-reducing Deltaproteobacteria respectively. There is evidence that methane oxidation is catalysed by enzymes related to those in methanogenesis, but the enzymes for sulfate reduction coupled to AOM have not been examined. We collected microbial mats with high AOM activity from a methane seep in the Black Sea. The mats consisted mainly of archaea of the ANME-2 group and bacteria of the Desulfosarcina-Desulfococcus group. Cell-free mat extract contained activities of enzymes involved in sulfate reduction to sulfide: ATP sulfurylase (adenylyl : sulfate transferase; Sat), APS reductase (Apr) and dissimilatory sulfite reductase (Dsr). We partially purified the enzymes by anion-exchange chromatography. The amounts obtained indicated that the enzymes are abundant in the mat, with Sat accounting for 2% of the soluble mat protein. N-terminal amino acid sequences of purified proteins suggested similarities to the corresponding enzymes of known species of sulfate-reducing bacteria. The deduced amino acid sequence of PCR-amplified genes of the Apr subunits is similar to that of Apr of the Desulfosarcina/Desulfococcus group. These results indicate that the major enzymes involved in sulfate reduction in the Back Sea microbial mats are of bacterial origin, most likely originating from the bacterial partner in the consortium. PMID:21392199

  19. MICROBIAL SULFATE REDUCTION AND METAL ATTENUATION IN PH 4 ACID MINE WATER

    EPA Science Inventory

    Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4 to 7.5). The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing...

  20. Desulfovirga adipica gen. nov., sp. nov., an adipate-degrading, gram-negative, sulfate-reducing bacterium.

    PubMed

    Tanaka, K; Stackebrandt, E; Tohyama, S; Eguchi, T

    2000-03-01

    A novel, mesophilic, Gram-negative bacterium was isolated from an anaerobic digestor for municipal wastewater. The bacterium degraded adipate in the presence of sulfate, sulfite, thiosulfate and elemental sulfur. (E)-2-Hexenedioate accumulated transiently in the degradation of adipate. (E)-2-Hexenedioate, (E)-3-hexenedioate, pyruvate, lactate, C1-C12 straight-chain fatty acids and C2-C10 straight-chain primary alcohols were also utilized as electron donors. 3-Phenylpropionate was oxidized to benzoate. The G + C content of the DNA was 60 mol%. 16S rDNA sequence analysis revealed that the new isolate clustered with species of the genus Syntrophobacter and Desulforhabdus amnigenus. Strain TsuAS1T resembles Desulforhabdus amnigenus DSM 10338T with respect to the ability to utilize acetate as an electron donor and the inability to utilize propionate without sulfate in co-culture with Methanospirillum hungatei DSM 864. Strains TsuAS1T and DSM 10338T form a 'non-syntrophic subcluster' within the genus Syntrophobacter. Desulfovirga adipica gen. nov., sp. nov. is proposed for the newly isolated bacterium, with strain TsuAS1T (= DSM 12016T) as the type strain. PMID:10758870

  1. Shellac formulations to reduce epiphytic survival of coliform bacteria on citrus fruit postharvest.

    PubMed

    McGuire, R G; Hagenmaier, R D

    2001-11-01

    Survival of the coliform bacteria Enterobacter aerogenes and Escherichia coli was monitored in a neutral carboxymethylcellulose formulation and in shellac formulations with various pH and concentrations of ethanol and the preservative paraben; populations were subsequently measured from the surface of citrus fruit coated with these formulations. Numbers of the two bacteria increased over 24 h from 10(6) CFU/ml to approximately 10(8) CFU/ml in the carboxymethylcellulose solution, but over this time numbers remained little changed in the neutral solution of shellac. The Enterobacter was more tolerant of alcohol over a 3-h period: although its numbers in a shellac solution with 10% ethanol dropped from more than 10(6) CFU/ml to just over 10(3) CFU/ml. E. coli and a third species. Klebsiella pneunoniae, declined toward the limit of detection (5 CFU/ ml) during this time. The addition of morpholine to increase the formulation pH to 9.0 caused numbers of bacteria to plummet to an undetectable level within 30 to 60 min. On Ruby Red grapefruit and Valencia oranges in storage at 13 degrees C numbers of E. aerogenes and E. coli declined over 2 weeks from 10(5) CFU/cm2 to less than 2.5 x 10(1), but most of the loss in numbers occurred within 1 day. Numbers remained significantly less on shellacked fruit compared with those applied in the carboxymethylcellulose coating, and a shellac coating prepared from a pH 9 solution was more toxic to these species than one in which 12% ethanol had been added to the neutral formulation. The addition of the preservative paraben in the basic shellac was further inhibitory. PMID:11726155

  2. Gargling with povidone-iodine reduces the transport of bacteria during oral intubation

    Microsoft Academic Search

    Junichi Ogata; Kouichiro Minami; Hiroshi Miyamoto; Takafumi Horishita; Midori Ogawa; Takeyoshi Sata; Hatsumi Taniguchi

    2004-01-01

    Purpose  Nosocomial pneumonia remains a common complication in patients undergoing endotracheal intubation. This study examined the\\u000a transport of bacteria into the trachea during endotracheal intubation, and evaluated the effects of gargling with povidone-iodine\\u000a on bacterial contamination of the tip of the intubation tube.\\u000a \\u000a \\u000a \\u000a Methods  In the gargling group, patients gargled with 25 mL of povidone-iodine (2.5 mg· mL?1). In the control group,

  3. A simple most probable number method for the enumeration of sulphate-reducing bacteria in biocide containing waters.

    PubMed

    Battersby, N S; Stewart, D J; Sharma, A P

    1985-04-01

    A simple most probable number (MPN) method has been developed for the enumeration of sulphate-reducing bacteria (SRB) in biocide-containing waters. The medium used is based on source water, it contains no toxic thioglycollate and is resistant to oxidation through mishandling. Reduction is by a suspension of Pseudomonas putida which acts as a powerful adsorbent of biguanide, phenolic, quaternary ammonium compound, glutaraldehyde and isothiazolone biocides. Good recoveries of SRB type strains were obtained using this method and were comparable to other published techniques. Recovery of SRB in mixed culture was comparable to that using a standard laboratory technique. PMID:3997694

  4. Using proteomic data to assess a genome-scale "in silico" model of metal reducing bacteria in the simulation of field-scale uranium bioremediation

    NASA Astrophysics Data System (ADS)

    Yabusaki, S.; Fang, Y.; Wilkins, M. J.; Long, P.; Rifle IFRC Science Team

    2011-12-01

    A series of field experiments in a shallow alluvial aquifer at a former uranium mill tailings site have demonstrated that indigenous bacteria can be stimulated with acetate to catalyze the conversion of hexavalent uranium in a groundwater plume to immobile solid-associated uranium in the +4 oxidation state. While this bioreduction of uranium has been shown to lower groundwater concentrations below actionable standards, a viable remediation methodology will need a mechanistic, predictive and quantitative understanding of the microbially-mediated reactions that catalyze the reduction of uranium in the context of site-specific processes, properties, and conditions. At the Rifle IFRC site, we are investigating the impacts on uranium behavior of pulsed acetate amendment, acetate-oxidizing iron and sulfate reducing bacteria, seasonal water table variation, spatially-variable physical (hydraulic conductivity, porosity) and geochemical (reactive surface area) material properties. The simulation of three-dimensional, variably saturated flow and biogeochemical reactive transport during a uranium bioremediation field experiment includes a genome-scale in silico model of Geobacter sp. to represent the Fe(III) terminal electron accepting process (TEAP). The Geobacter in silico model of cell-scale physiological metabolic pathways is comprised of hundreds of intra-cellular and environmental exchange reactions. One advantage of this approach is that the TEAP reaction stoichiometry and rate are now functions of the metabolic status of the microorganism. The linkage of in silico model reactions to specific Geobacter proteins has enabled the use of groundwater proteomic analyses to assess the accuracy of the model under evolving hydrologic and biogeochemical conditions. In this case, the largest predicted fluxes through in silico model reactions generally correspond to high abundances of proteins linked to those reactions (e.g. the condensation reaction catalyzed by the protein citrate synthase that generates citrate from acetyl-CoA and oxaloacetate). Model discrepancies with the proteomic data, such as the prediction of shifts associated with nitrogen limitation, revealed pathways in the in silico code that could be modified to more accurately predict metabolic processes that occur in the subsurface. The potential outcome of this approach is the engineering of electron donor (e.g., acetate), terminal electron acceptor [e.g., U(VI)], and biogeochemical conditions that enhance the desired metabolic pathways of the target microorganism(s) to effect cost-effective uranium bioreduction.

  5. Anaerobic bacteria from hypersaline environments.

    PubMed Central

    Ollivier, B; Caumette, P; Garcia, J L; Mah, R A

    1994-01-01

    Strictly anaerobic halophiles, namely fermentative, sulfate-reducing, homoacetogenic, phototrophic, and methanogenic bacteria are involved in the oxidation of organic carbon in hypersaline environments. To date, six anaerobic fermentative genera, containing nine species, have been described. Two of them are homoacetogens. Six species belong to the family Haloanaerobiaceae, as indicated by their unique 16S rRNA oligonucleotide sequences. Desulfohalobium retbaense and Desulfovibrio halophilus represent the only two moderately halophilic sulfate reducers so far reported. Among anoxygenic phototrophic anaerobes, a few purple bacteria with optimal growth at salinities between 6 and 11% NaCl have been isolated from hypersaline habitats. They belong to the genera Rhodospirillum, Chromatium, Thiocapsa, and Ectothiorhodospira. The commonest organisms isolated so far are Chromatium salexigens, Thiocapsa halophila, and Rhodospirillum salinarum. Extremely halophilic purple bacteria have most commonly been isolated from alkaline brines and require about 20 to 25% NaCl for optimal growth. They belong to the family Ectothiorodhospiraceae. Their osmoregulation involves synthesis or uptake of compatible solutes such as glycine-betaine that accumulate in their cytoplasm. The existence of methanogens in hypersaline environments is related to the presence of noncompetitive substrates such as methylamines, which originate mainly from the breakdown of osmoregulatory amines. Methanogenesis probably does not contribute to the mineralization of carbohydrates at NaCl concentrations higher than 15%. Above this concentration, sulfate reduction is probably the main way to oxidize H2 (although at rates too low to use up all the H2 formed) and occupies a terminal function kn the degradation of carbohydrates. Three genera and five species of halophilic methylotrophic methanogens have been reported. A bloom of phototrophic bacteria in the marine salterns of Salins-de-Giraud, located on the Mediterranean French coast in the Rhone Delta, is also described. PMID:8177169

  6. Humic Acid-Oxidizing, Nitrate-Reducing Bacteria in Agricultural Soils

    PubMed Central

    Van Trump, J. Ian; Wrighton, Kelly C.; Thrash, J. Cameron; Weber, Karrie A.; Andersen, Gary L.; Coates, John D.

    2011-01-01

    ABSTRACT This study demonstrates the prevalence, phylogenetic diversity, and physiology of nitrate-reducing microorganisms capable of utilizing reduced humic acids (HA) as electron donors in agricultural soils. Most probable number (MPN) enumeration of agricultural soils revealed large populations (104 to 106 cells g?1 soil) of microorganisms capable of reducing nitrate while oxidizing the reduced HA analog 2,6-anthrahydroquinone disulfonate (AH2DS) to its corresponding quinone. Nitrate-dependent HA-oxidizing organisms isolated from agricultural soils were phylogenetically diverse and included members of the Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria. Advective up-flow columns inoculated with corn plot soil and amended with reduced HA and nitrate supported both HA oxidation and enhanced nitrate reduction relative to no-donor or oxidized HA controls. The additional electron donating capacity of reduced HA could reasonably be attributed to the oxidation of reduced functional groups. Subsequent 16S rRNA gene-based high-density oligonucleotide microarray (PhyloChip) indicated that reduced HA columns supported the development of a bacterial community enriched with members of the Acidobacteria, Firmicutes, and Betaproteobacteria relative to the no-donor control and initial inoculum. This study identifies a previously unrecognized role for HA in stimulating denitrification processes in saturated soil systems. Furthermore, this study indicates that reduced humic acids impact soil geochemistry and the indigenous bacterial community composition. PMID:21750120

  7. Light scattering spectra of sulfur-reducing bacteria Desulfuromonas acetoxidans under the influence of ions Fe metals

    NASA Astrophysics Data System (ADS)

    Bilyy, Oleksandr I.; Vasyliv, Oresta M.; Hnatush, Svitlana O.

    2012-01-01

    Desulfuromonas acetoxidans are uncoloured gram-negative sulfur bacteria that inhabit sulfur containing aquatic environments. These are gram-negative obligatory anaerobes that have an ability to reduce S0 to H2S and Fe3+ to Fe2+ in the processes of dissimilation Sulfur- and Fe (III)-reduction. Existence of Sulfur and Ferric ions in the anaerobic sediments causes binding of hydrogen sulfide which diffuses from the zone of sulfur reducing. As a result hydrogen sulfide is detoxificated. The ability of these bacteria to use Sulfur or Ferric ions as acceptors of electrons during organic carbon oxidation causes their special adaptation to the changes of surrounding environment. Interaction between bacterial Desulfuromonas acetoxidans cells and different concentrations of ferrous Fe2+ and ferric Fe3+ ions possibly could cause the changes of cells' light scattering characteristics. The changes of cells relative content and their size distribution during five days of cultivation under the influence of FeSO4 and FeCl3×6H2O in concentration from 0.01 to 10 mM was investigated by the new method of measurement. It includes sounding of flow suspended bacterial cells by monochromatic coherent light, registration of signals of co-operation of sounding radiation with the explored microbiological objects by detects of the changes of amplitudes and durations of scattered light impulses. Under the influence from 0.01 to 10 mM of FeSO4 the maximum of cells' size distribution changed from 0.55 to 0.62 ?m and effect of investigated range of FeCl3×6H2O concentrations caused it changes from 0.43 to 0.49 ?m during five days of sulfurreducing Desulfuromonas acetoxidans bacteria growth.

  8. Light scattering spectra of sulfur-reducing bacteria Desulfuromonas acetoxidans under the influence of ions Fe metals

    NASA Astrophysics Data System (ADS)

    Bilyy, Oleksandr I.; Vasyliv, Oresta M.; Hnatush, Svitlana O.

    2011-09-01

    Desulfuromonas acetoxidans are uncoloured gram-negative sulfur bacteria that inhabit sulfur containing aquatic environments. These are gram-negative obligatory anaerobes that have an ability to reduce S0 to H2S and Fe3+ to Fe2+ in the processes of dissimilation Sulfur- and Fe (III)-reduction. Existence of Sulfur and Ferric ions in the anaerobic sediments causes binding of hydrogen sulfide which diffuses from the zone of sulfur reducing. As a result hydrogen sulfide is detoxificated. The ability of these bacteria to use Sulfur or Ferric ions as acceptors of electrons during organic carbon oxidation causes their special adaptation to the changes of surrounding environment. Interaction between bacterial Desulfuromonas acetoxidans cells and different concentrations of ferrous Fe2+ and ferric Fe3+ ions possibly could cause the changes of cells' light scattering characteristics. The changes of cells relative content and their size distribution during five days of cultivation under the influence of FeSO4 and FeCl3×6H2O in concentration from 0.01 to 10 mM was investigated by the new method of measurement. It includes sounding of flow suspended bacterial cells by monochromatic coherent light, registration of signals of co-operation of sounding radiation with the explored microbiological objects by detects of the changes of amplitudes and durations of scattered light impulses. Under the influence from 0.01 to 10 mM of FeSO4 the maximum of cells' size distribution changed from 0.55 to 0.62 ?m and effect of investigated range of FeCl3×6H2O concentrations caused it changes from 0.43 to 0.49 ?m during five days of sulfurreducing Desulfuromonas acetoxidans bacteria growth.

  9. Dissolution of Arsenic Minerals Mediated by Dissimilatory Arsenate Reducing Bacteria: Estimation of the Physiological Potential for Arsenic Mobilization

    PubMed Central

    Lukasz, Drewniak; Liwia, Rajpert; Aleksandra, Mantur; Aleksandra, Sklodowska

    2014-01-01

    The aim of this study was characterization of the isolated dissimilatory arsenate reducing bacteria in the context of their potential for arsenic removal from primary arsenic minerals through reductive dissolution. Four strains, Shewanella sp. OM1, Pseudomonas sp. OM2, Aeromonas sp. OM4, and Serratia sp. OM17, capable of anaerobic growth with As (V) reduction, were isolated from microbial mats from an ancient gold mine. All of the isolated strains: (i) produced siderophores that promote dissolution of minerals, (ii) were resistant to dissolved arsenic compounds, (iii) were able to use the dissolved arsenates as the terminal electron acceptor, and (iii) were able to use copper minerals containing arsenic minerals (e.g., enargite) as a respiratory substrate. Based on the results obtained in this study, we postulate that arsenic can be released from some As-bearing polymetallic minerals (such as copper ore concentrates or middlings) under reductive conditions by dissimilatory arsenate reducers in indirect processes. PMID:24724102

  10. Desulfosoma profundi sp. nov., a thermophilic sulfate-reducing bacterium isolated from a deep terrestrial geothermal spring in France.

    PubMed

    Grégoire, Patrick; Fardeau, Marie-Laure; Guasco, Sophie; Lagière, Joël; Cambar, Jean; Michotey, Valérie; Bonin, Patricia; Ollivier, Bernard

    2012-03-01

    A novel strictly anaerobic bacterium designated SPDX02-08(T) was isolated from a deep terrestrial geothermal spring located in southwest France. Cells (1-2 × 2-6 ?m) were non-motile, non sporulating and stained Gram negative. Strain SPDX02-08(T) grew at a temperature between 40 and 60°C (optimum 55°C), pH between 6.3 and 7.3 (optimum 7.2) and a NaCl concentration between 0 and 5 g/l (optimum 2 g/l). Sulfate, thiosulfate and sulfite were used as terminal electron acceptors, but not elemental sulfur, nitrate, nitrite, Fe (III) or fumarate. In the presence of sulfate, strain SPDX02-08(T) completely oxidized pyruvate, propionate, butyrate, isobutyrate, valerate, isovalerate and hexadecanoate. Stoichiometric measurements revealed a complete oxidation of part of lactate (0.125 mol of acetate produced per mole lactate oxidized). Strain SPDX02-08(T) required yeast extract to oxidize formate and H(2) but did not grow autotrophically on H(2). Among the substrates tested, only pyruvate was fermented. The G+C content of the genomic DNA was 57.6 mol%. Major cellular fatty acids of strain SPDX02-08(T) were iso-C(15:0), C(15:0), and C(16:0). Phylogenetic analysis of the 16S small-subunit (SSU) ribosomal RNA gene sequence indicated that strain SPDX02-08(T) belongs to the genus Desulfosoma, family Syntrophobacteraceae, having Desulfosoma caldarium as its closest phylogenetic relative (97.6% similarity). The mean DNA/DNA reassociation value between strain SPDX02-08(T) and Desulfosoma caldarium was 16.9 ± 2.7%. Based on the polyphasic differences, strain SPDX02-08(T) is proposed to be assigned as a new species of the genus Desulfosoma, Desulfosoma profundi sp. nov. (DSM 22937(T) = JCM 16410(T)). GenBank accession number for the 16S rRNA gene sequence of strain SPDX02-08(T) is HM056226. PMID:22120904

  11. Effects of microbial activity and electron shuttles on the reduction of U(VI) under Fe(III)- and sulfate-reducing conditions

    NASA Astrophysics Data System (ADS)

    O'Loughlin, E. J.; Boyanov, M.; Kwon, M.; Long, P. E.; Williams, K. H.; Kemner, K. M.

    2009-12-01

    Recent studies suggest that electron shuttles such as low molecular mass quinones and humic substances may play a role in many redox reactions involved in contaminant transformations and the biogeochemical cycling of redox active elements in aquatic and terrestrial environments. In an effort to better define the role(s) of electron shuttles in biogeochemical processes in natural and engineered subsurface environments, we are investigating the effects of 9,10-anthraquinone-2,6-disulfonate (AQDS), a synthetic electron shuttle often used as a surrogate for quinone moieties in humic substances, on transformations of Fe, S, and U under conditions favorable for dissimilatory iron and sulfate reduction. Experiments were conducted in serum bottles containing a defined mineral medium amended with 30 mM Fe(III), 5 mM sulfate, and 10 mM acetate. Duplicate bottles with and without 100 ?M AQDS were prepared. Fe(III) was provided as natural sienna, an iron-rich earth consisting primarily of quartz and goethite. The serum bottles were sparged with Ar and inoculated with sediment from the Rifle, CO Integrated Field Research Challenge (IFRC) site and monitored over time for Fe(II) production and sulfate and acetate consumption. After the system reached steady state with respect to Fe(III) and sulfate reduction, aliquots of suspension were collected from each system (i.e., with and without AQDS) for U(VI) reduction experiments. One set from each system was pasteurized at 70 °C for 1 hr; the other set was not pasteurized. The suspensions were spiked with 500 ?M U(VI). After 48 h, 100% of the added U was removed from solution in the non-pasteurized AQDS system. However, only 58%, 25%, and 11% of added U was removed in the no AQDS non-pasteurized, AQDS pasteurized, and no AQDS pasteurized systems, respectively. U XANES analysis of the solids in each of these suspensions indicated that, with the exception of the pasteurized system without AQDS, the majority (85-95%) of the U associated with the solids was reduced to U(IV). The results of U EXAFS analysis of the solids with and without AQDS (not pasteurized) are consistent with the formation of nanoparticulate uraninite. The results of this study suggest that microbial reduction was the dominant process contributing to the reduction of U(VI) over the timescale of this experiment and that the presence of AQDS enhanced both biotic and abtiotic/microbially mediated U(VI) reduction.

  12. Anaerobic biodegradation of o-, m- and p-cresol by sulfate-reducing bacterial enrichment cultures obtained from a shallow anoxic aquifer

    SciTech Connect

    Suflita, J.M.; Liang, L.; Saxena, A.

    1989-01-01

    Sulfate-reducing bacterial enrichments were obtained from a shallow anoxic aquifer for their ability to metabolize either o-, m-, or p-cresol. GC/MS and simultaneous adaptation experiments suggested that the anaerobic decomposition of p-cresol proceeds by the initial oxidation of the aryl methyl group to form p-hydroxybenzoic acid. The intermediate was then converted to benzoic acid. Benzoic acid and a hydroxybenzaldehyde were also found in spent culture fluids from an o-cresol-degrading enrichment culture. The result, in addition to others, suggested that o-cresol may also be anaerobically degraded by the oxidation of the methyl substituent. An alternate pathway for anaerobic m-cresol decomposition might exist. Enrichment cultures obtained with either p- or o-cresol degraded both of these substrates but not m-cresol. In contrast a m-cresol enrichment culture did not metabolize the ortho or para isomers. Anaerobic biodegradation in all enrichment cultures was inhibited by molybdate and oxygen, and was dependent on the presence of sulfate as a terminal electron acceptor.

  13. Bacteria and zymosan opsonized with histone, dextran sulfate, and polyanetholesulfonate trigger intense chemiluminescence in human blood leukocytes and platelets and in mouse macrophages

    Microsoft Academic Search

    Isaac Ginsburg; Ruth Borinsky; Meir Lahav; K. E. Gillert; Sabina Falkenberg; Michael Winkler; Sybille Muller

    1982-01-01

    Human blood leukocytes and platelets and mouse peritoneal macrophages emit very rapid and very intense Luminol-dependent chemiluminescence (CL) signals when treated with streptococci, staphylococci, or with zymosan, which have been preopsonized with arginine-rich histone, dextran sulfate or polyanetholesulfonate (liquoid). Liquoid alone at 10–30µg\\/2×105 leukocytes also triggers intense CL responses in the absence of a carrier. Strong CL can also be

  14. Application of molecular techniques to evaluate the methanogenic archaea and anaerobic bacteria in the presence of oxygen with different COD:Sulfate ratios in a UASB reactor

    Microsoft Academic Search

    Julia Sumiko Hirasawa; Arnaldo Sarti; Nora Katia Saavedra Del Aguila; Maria Bernadete A. Varesche

    2008-01-01

    In this paper, the microbial characteristics of the granular sludge in the presence of oxygen (3.0±0.7mgO2l?1) were analyzed using molecular biology techniques. The granules were provided by an upflow anaerobic sludge blanket (UASB) operated over 469 days and fed with synthetic substrate. Ethanol and sulfate were added to obtain different COD\\/SO42? ratios (3.0, 2.0, and 1.6). The results of fluorescent

  15. Are sulfur isotope ratios sufficient to determine the antiquity of sulfate reduction. [implications for chemical evolution

    NASA Technical Reports Server (NTRS)

    Ashendorf, D.

    1980-01-01

    Possible limitations on the use of sulfur isotope ratios in sedimentary sulfides to infer the evolution of microbial sulfate reduction are discussed. Current knowledge of the ways in which stable sulfur isotope ratios are altered by chemical and biological processes is examined, with attention given to the marine sulfur cycle involving various microbial populations, and sulfur reduction processes, and it is noted that satisfactory explanations of sulfur isotope ratios observed in live organisms and in sediments are not yet available. It is furthermore pointed out that all members of the same genus of sulfate reducing bacteria do not always fractionate sulfur to the same extent, that the extent of sulfur fractionation by many sulfate-reducing organisms has not yet been determined, and that inorganic processes can also affect sulfur isotope fractionation values. The information currently available is thus concluded to be insufficient to determine the time of initial appearance of biological sulfate reduction.

  16. Impact of Iron-Reducing Bacteria on the Corrosion Rate of Carbon Steel under Simulated Geological Disposal Conditions.

    PubMed

    Schütz, Marta K; Schlegel, Michel L; Libert, Marie; Bildstein, Olivier

    2015-06-16

    The current projects for the disposal of high-level radioactive waste rely on underground burial and confinement by metallic envelopes that are susceptible to corrosion processes. The impact of microbial activity must be fully clarified in order to provide biological parameters for predictive reactive transport models. This study investigates the impact of hydrogenotrophic iron-reducing bacteria (Shewanella oneidensis strain MR-1) on the corrosion rate of carbon steel under simulated geological disposal conditions by using a geochemical approach. It was found that corrosion damage changes mostly according to the experimental solution (i.e., chemical composition). Magnetite and vivianite were identified as the main corrosion products. In the presence of bacteria, the corrosion rate increased by a factor of 1.3 (according to weight loss analysis) to 1.8 (according to H2 measurements), and the detected amount of magnetite diminished. The mechanism likely to enhance corrosion is the destabilization and dissolution of the passivating magnetite layer by reduction of structural Fe(III) coupled to H2 oxidation. PMID:25988515

  17. The effect of various iron hydroxide concentrations on the anaerobic fermentation of sulfate-containing model wastewater

    Microsoft Academic Search

    V. P. Stabnikov; V. N. Ivanov

    2006-01-01

    The addition of iron hydroxide and iron-reducing bacteria into a reactor for anaerobic processing of sulfate-containing wastewater\\u000a was shown to decrease sulfate reduction and sulfide concentration, while increasing the total organic carbon (TOC) and methane\\u000a production. The effect of iron (III) in sulfate-containing wastewater depended on its dose, which can be expressed as molar\\u000a ratio Fe(III)\\/SO\\u000a 4\\u000a 2?\\u000a . Sulfide

  18. Remediation of chromium-contaminated water using biogenic nano-sized materials and metal-reducing bacteria.

    PubMed

    Seo, Hyunhee; Sun, Eunyoung; Roh, Yul

    2013-06-01

    As an environmental nanotechnology, nano-sized materials have the potential to create novel and effective in-situ and ex-situ treatments for contaminated groundwater due to its high catalytic reactivity, large surface area, and dispersibility. In this study the efficiency of Cr(VI) reduction and immobilization using biotic and abiotic nano-sized materials (NSMs) and metal-reducing bacteria (MRB) was evaluated to remediate Cr(VI)-contaminated groundwater in batch and column tests. The results of this study revealed that the combination of the mixed MRB and bio-FeS/siderite performed the highest efficiency of Cr(VI) reduction and immobilization. Cr(VI) reduction by MRB and NSMs could impact on solubility of Cr(VI) and geochemical changes favorable for precipitation and adsorption. PMID:23862512

  19. Significance of ? 34S and evaluation of its imprint on sedimentary organic matter: I. The role of reduced sulfur species in the diagenetic stage: A conceptual review

    Microsoft Academic Search

    Zeev Aizenshtat; Alon Amrani

    2004-01-01

    Both carbon and sulfur cycles in the geosphere are biogenically and chemically interwoven. Sulfate is the main source for sulfur in marine sediments. The incorporation of sulfur into biogenic organic matter (OM) via the assimilatory process has very little isotopic discrimination. The pioneering work by Kaplan and Rittenberg showed that sulfate-reducing bacteria (SRB) oxidize organic carbon to CO2 while producing

  20. Transformation of vivianite by anaerobic nitrate-reducing iron-oxidizing bacteria

    Microsoft Academic Search

    J. MIOT; K. BENZERARA; G. MORIN; S. BERNARD; O. BEYSSAC; E. LARQUET; A. KAPPLER; F. GUYOT

    2009-01-01

    In phosphate-rich environments, vivianite (FeII3(PO4)2 ,8 H2O) is an important sink for dissolved Fe(II) and is considered as a very stable mineral due to its low solubility at neutral pH. In the present study, we report the mineralogical transformation of vivianite in cultures of the nitrate-reducing iron-oxidizing bacterial strain BoFeN1 in the presence of dissolved Fe(II). Vivianite was first transformed