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Sample records for green sulfur bacteria

  1. Comparative Genomics of Green Sulfur Bacteria

    DEFF Research Database (Denmark)

    Ussery, David; Davenport, C; Tümmler, B

    2010-01-01

    Eleven completely sequenced Chlorobi genomes were compared in oligonucleotide usage, gene contents, and synteny. The green sulfur bacteria (GSB) are equipped with a core genome that sustains their anoxygenic phototrophic lifestyle by photosynthesis, sulfur oxidation, and CO(2) fixation. Whole-genome gene family and single gene sequence comparisons yielded similar phylogenetic trees of the sequenced chromosomes indicating a concerted vertical evolution of large gene sets. Chromosomal synteny of g...

  2. Comparative Genomics of Green Sulfur Bacteria

    DEFF Research Database (Denmark)

    Ussery, David; Davenport, C

    2010-01-01

    Eleven completely sequenced Chlorobi genomes were compared in oligonucleotide usage, gene contents, and synteny. The green sulfur bacteria (GSB) are equipped with a core genome that sustains their anoxygenic phototrophic lifestyle by photosynthesis, sulfur oxidation, and CO(2) fixation. Whole-genome gene family and single gene sequence comparisons yielded similar phylogenetic trees of the sequenced chromosomes indicating a concerted vertical evolution of large gene sets. Chromosomal synteny of genes is not preserved in the phylum Chlorobi. The accessory genome is characterized by anomalous oligonucleotide usage and endows the strains with individual features for transport, secretion, cell wall, extracellular constituents, and a few elements of the biosynthetic apparatus. Giant genes are a peculiar feature of the genera Chlorobium and Prosthecochloris. The predicted proteins have a huge molecular weight of 10(6), and are probably instrumental for the bacteria to generate their own intimate (micro)environment.

  3. Genomic Insights into the Sulfur Metabolism of Phototrophic Green Sulfur Bacteria

    DEFF Research Database (Denmark)

    Frigaard, Niels-Ulrik; Bryant, Donald A.

    2008-01-01

    Green sulfur bacteria (GSB) utilize various combinations of sulfide, elemental sulfur, thiosulfate, ferrous iron, and hydrogen for anaerobic photoautotrophic growth. Genome sequence data is currently available for 12 strains of GSB. We present here a genome-based survey of the distribution and phylogenies of genes involved in oxidation of sulfur compounds in these strains. Sulfide:quinone reductase, encoded by sqr, is the only known sulfur-oxidizing enzyme found in all strains. All sulfide-utili...

  4. Mechanisms and evolution of oxidative sulfur metabolism in green sulfur bacteria

    DEFF Research Database (Denmark)

    Gregersen, Lea Haarup; Bryant, Donald A.

    2011-01-01

    Green sulfur bacteria (GSB) constitute a closely related group of photoautotrophic and thiotrophic bacteria with limited phenotypic variation. They typically oxidize sulfide and thiosulfate to sulfate with sulfur globules as an intermediate. Based on genome sequence information from 15 strains, the distribution and phylogeny of enzymes involved in their oxidative sulfur metabolism was investigated. At least one homolog of sulfide:quinone oxidoreductase (SQR) is present in all strains. In all sulfur-oxidizing GSB strains except the earliest diverging Chloroherpeton thalassium, the sulfide oxidation product is further oxidized to sulfite by the dissimilatory sulfite reductase (DSR) system. This system consists of components horizontally acquired partly from sulfide-oxidizing and partly from sulfate-reducing bacteria. Depending on the strain, the sulfite is probably oxidized to sulfate by one of two different mechanisms that have different evolutionary origins: adenosine-5'-phosphosulfate reductase or polysulfide reductase-like complex 3. Thiosulfate utilization by the SOX system in GSB has apparently been acquired horizontally from Proteobacteria. SoxCD does not occur in GSB, and its function in sulfate formation in other bacteria has been replaced by the DSR system in GSB. Sequence analyses suggested that the conserved soxJXYZAKBW gene cluster was horizontally acquired by Chlorobium phaeovibrioides DSM 265 from the Chlorobaculum lineage and that this acquisition was mediated by a mobile genetic element. Thus, the last common ancestor of currently known GSB was probably photoautotrophic, hydrogenotrophic, and contained SQR but not DSR or SOX. In addition, the predominance of the Chlorobium-Chlorobaculum-Prosthecochloris lineage among cultured GSB could be due to the horizontally acquired DSR and SOX systems. Finally, based upon structural, biochemical, and phylogenetic analyses, a uniform nomenclature is suggested for sqr genes in prokaryotes.

  5. Sulfur metabolism in phototrophic sulfur bacteria

    DEFF Research Database (Denmark)

    Frigaard, Niels-Ulrik; Dahl, Christiane

    2008-01-01

    Phototrophic sulfur bacteria are characterized by oxidizing various inorganic sulfur compounds for use as electron donors in carbon dioxide fixation during anoxygenic photosynthetic growth. These bacteria are divided into the purple sulfur bacteria (PSB) and the green sulfur bacteria (GSB). They utilize various combinations of sulfide, elemental sulfur, and thiosulfate and sometimes also ferrous iron and hydrogen as electron donors. This review focuses on the dissimilatory and assimilatory metab...

  6. Chromatic acclimation and population dynamics of green sulfur bacteria grown with spectrally tailored light

    CERN Document Server

    Saikin, Semion K; Huh, Joonsuk; Hannout, Moataz; Wang, Yaya; Zare, Farrokh; Aspuru-Guzik, Alan; Tang, Joseph Kuo-Hsiang

    2014-01-01

    Living organisms have to adjust to their surrounding in order to survive in stressful conditions. We study this mechanism in one of most primitive creatures - photosynthetic green sulfur bacteria. These bacteria absorb photons very efficiently using the chlorosome antenna complexes and perform photosynthesis in extreme low-light environments. How the chlorosomes in green sulfur bacteria are acclimated to the stressful light conditions, for instance, if the spectrum of light is not optimal for absorption, is unknown. Studying Chlorobaculum tepidum cultures with far-red to near-infrared light-emitting diodes, we found that these bacteria react to changes in energy flow by regulating the amount of light-absorbing pigments and the size of the chlorosomes. Surprisingly, our results indicate that the bacteria can survive in near-infrared lights capturing low-frequency photons by the intermediate units of the light-harvesting complex. The latter strategy may be used by the species recently found near hydrothermal ve...

  7. Atomistic study of energy funneling in the light-harvesting complex of green sulfur bacteria

    CERN Document Server

    Huh, Joonsuk; Brookes, Jennifer C; Valleau, Stéphanie; Fujita, Takatoshi; Aspuru-Guzik, Alán

    2013-01-01

    Phototrophic organisms such as plants, photosynthetic bacteria and algae use microscopic complexes of pigment molecules to absorb sunlight. Within the light-harvesting complexes, which frequently have multiple functional and structural subunits, the energy is transferred in the form of molecular excitations with very high efficiency. Green sulfur bacteria are considered to be amongst the most efficient light-harvesting organisms. Despite multiple experimental and theoretical studies of these bacteria the physical origin of the efficient and robust energy transfer in their light-harvesting complexes is not well understood. To study excitation dynamics at the systems level we introduce an atomistic model that mimic a complete light-harvesting apparatus of green sulfur bacteria. The model contains about 4000 pigment molecules and comprises a double wall roll for the chlorosome, a baseplate and six Fenna-Matthews-Olson trimer complexes. We show that the fast relaxation within functional subunits combined with the...

  8. The green non-sulfur bacteria: a deep branching in the eubacterial line of descent

    Science.gov (United States)

    Oyaizu, H.; Debrunner-Vossbrinck, B.; Mandelco, L.; Studier, J. A.; Woese, C. R.

    1987-01-01

    Ribosomal RNA sequence comparisons define a phylogenetic grouping, the green non-sulfur bacteria and relatives (GNS), known to contain the genera Chloroflexus, Herpetosiphon and Thermomicrobium--organisms that have little phenotypic similarity. The unit is phylogenetically deep, but entirely distinct from any other eubacterial division (phylum). It is also relatively ancient--branching from the common eubacterial stem earlier than any other group of eubacteria reported thus far. The group phenotype is predominantly thermophilic, and its thermophilic members, especially Thermomicrobium, are more slowly evolving than Herpetosiphon, a mesophile. The GNS unit appears significantly older than either the green sulfur bacteria or the cyanobacteria--making it likely that organisms such as Chloroflexus, not the cyanobacteria, generated the oldest stromatolites, which formed over three billion years ago.

  9. Both Forward and Reverse TCA Cycles Operate in Green Sulfur Bacteria*

    OpenAIRE

    TANG, KUO-HSIANG; Blankenship, Robert E

    2010-01-01

    The anoxygenic green sulfur bacteria (GSBs) assimilate CO2 autotrophically through the reductive (reverse) tricarboxylic acid (RTCA) cycle. Some organic carbon sources, such as acetate and pyruvate, can be assimilated during the phototrophic growth of the GSBs, in the presence of CO2 or HCO3?. It has not been established why the inorganic carbonis required for incorporating organic carbon for growth and how the organic carbons are assimilated. In this report, we probed carbon flux during auto...

  10. 217 000-year-old DNA sequences of green sulfur bacteria in Mediterranean sapropels and their implications for the reconstruction of the paleoenvironment.

    Science.gov (United States)

    Coolen, Marco J L; Overmann, Jörg

    2007-01-01

    Deep-sea sediments of the eastern Mediterranean harbour a series of dark, organic carbon-rich layers, so-called sapropels. Within these layers, the carotenoid isorenieratene was detected. Since it is specific for the obligately anaerobic phototrophic green sulfur bacteria, the presence of isorenieratene may suggest that extended water column anoxia occurred in the ancient Mediterranean Sea during periods of sapropel formation. Only three carotenoids (isorenieratene, beta-isorenieratene and chlorobactene) are typical for green sulfur bacteria and thus do not permit to differentiate between the approximately 80 known phylotypes. In order to reconstruct the paleoecological conditions in more detail, we searched for fossil 16S rRNA gene sequences of green sulfur bacteria employing ancient DNA methodology. 540 bp-long fossil sequences could indeed be amplified from up to 217 000-year-old sapropels. In addition, such sequences were also recovered from carbon-lean intermediate sediment layers deposited during times of an entirely oxic water column. Unexpectedly, however, all the recovered 16S rRNA gene sequences grouped with freshwater or brackish, rather than truly marine, types of green sulfur bacteria. It is therefore feasible that the molecular remains of green sulfur bacteria originated from populations which thrived in adjacent freshwater or estuarine coastal environments rather than from an indigenous pelagic population. PMID:17227428

  11. Temperature and Carbon Assimilation Regulate the Chlorosome Biogenesis in Green Sulfur Bacteria

    CERN Document Server

    Tang, Joseph Kuo-Hsiang; Pingali, Sai Venkatesh; Enriquez, Miriam M; Huh, Joonsuk; Frank, Harry A; Urban, Volker S; Aspuru-Guzik, Alan

    2013-01-01

    Green photosynthetic bacteria adjust the structure and functionality of the chlorosome - the light absorbing antenna complex - in response to environmental stress factors. The chlorosome is a natural self-assembled aggregate of bacteriochlorophyll (BChl) molecules. In this study we report the regulation of the biogenesis of the Chlorobaculum tepidum chlorosome by carbon assimilation in conjunction with temperature changes. Our studies indicate that the carbon source and thermal stress culture of Cba. tepidum grows slower and incorporates less BChl c in the chlorosome. Compared with the chlorosome from other cultural conditions we investigated, the chlorosome from the carbon source and thermal stress culture displays: (a) smaller cross-sectional radius and overall size; (b) simplified BChl c homologues with smaller side chains; (c) blue-shifted Qy absorption maxima and (d) a sigmoid-shaped circular dichroism (CD) spectra. Using a theoretical model we analyze how the observed spectral modifications can be assoc...

  12. Characterization of a plant-like protochlorophyllide a divinyl reductase in green sulfur bacteria.

    Science.gov (United States)

    Chew, Aline Gomez Maqueo; Bryant, Donald A

    2007-02-01

    The green sulfur bacterium Chlorobium tepidum synthesizes three types of (bacterio)chlorophyll ((B)Chl): BChl a(P), Chl a(PD), and BChl c(F). During the synthesis of all three molecules, a C-8 vinyl substituent is reduced to an ethyl group, and in the case of BChl c(F), the C-8(2) carbon of this ethyl group is subsequently methylated once or twice by the radical S-adenosylmethionine enzyme BchQ. The C. tepidum genome contains homologs of two genes, bchJ (CT2014) and CT1063, that are highly homologous to genes, bchJ and AT5G18660, and that have been reported to encode C-8 vinyl reductases in Rhodobacter capsulatus and Arabidopsis thaliana, respectively. To determine which gene product actually encodes a C-8 vinyl reductase activity, the bchJ and CT1063 genes were insertionally inactivated in C. tepidum. All three Chls synthesized by the CT1063 mutant of C. tepidum have a C-8 vinyl group. Using NADPH but not NADH as reductant, recombinant BciA reduces the C-8 vinyl group of 3,8-divinyl-protochlorophyllide in vitro. These data demonstrate that CT1063, renamed bciA, encodes a C-8 divinyl reductase in C. tepidum. The bchJ mutant produces detectable amounts of Chl a(PD), BChl a(P), and BChl c(F), all of which have reduced C-8 substituents, but the mutant cells secrete large amounts of 3,8-divinyl-protochlorophyllide a into the growth medium and have a greatly reduced BChl c(F) content. The results suggest that BchJ may play an important role in substrate channeling and/or regulation of Chl biosynthesis but show that it is not a vinyl reductase. Because only some Chl-synthesizing organisms possess homologs of bciA, at least two types of C-8 vinyl reductases must occur. PMID:17148453

  13. Comparison of Optimal Thermodynamic Models of the Tricarboxylic Acid Cycle from Heterotrophs, Cyanobacteria, and Green Sulfur Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Dennis G.; Jaramillo Riveri, Sebastian I.; Baxter, Douglas J.; Cannon, William R.

    2014-12-15

    We have applied a new stochastic simulation approach to predict the metabolite levels, energy flow, and material flux in the different oxidative TCA cycles found in E. coli and Synechococcus sp. PCC 7002, and in the reductive TCA cycle typical of chemolithoautotrophs and phototrophic green sulfur bacteria such as Chlorobaculum tepidum. The simulation approach is based on equations of state and employs an assumption similar to that used in transition state theory. The ability to evaluate the thermodynamics of metabolic pathways allows one to understand the relationship between coupling of energy and material gradients in the environment and the selforganization of stable biological systems, and it is shown that each cycle operates in the direction expected due to its environmental niche. The simulations predict changes in metabolite levels and flux in response to changes in cofactor concentrations that would be hard to predict without an elaborate model based on the law of mass action. In fact, we show that a thermodynamically unfavorable reaction can still have flux in the forward direction when it is part of a reaction network. The ability to predict metabolite levels, energy flow and material flux should be significant for understanding the dynamics of natural systems and for understanding principles for engineering organisms for production of specialty chemicals, such as biofuels.

  14. Sulfur-oxidizing bacteria in environmental technology.

    Science.gov (United States)

    Pokorna, Dana; Zabranska, Jana

    2015-11-01

    Hydrogen sulfide is widely known as the most undesirable component of biogas that caused not only serious sensoric and toxic problems, but also corrosion of concrete and steel structures. Many agricultural and industrial waste used in biogas production, may contain a large amount of substances that serve as direct precursors to the formation of sulfide sulfur-sources of hydrogen sulfide in the biogas. Biological desulfurization methods are currently promoted to abiotic methods because they are less expensive and do not produce undesirable materials which must be disposed of. The final products of oxidation of sulfides are no longer hazardous. Biological removal of sulfide from a liquid or gaseous phase is based on the activity of sulfur-oxidizing bacteria. They need an oxidizing agent such as an acceptor of electrons released during the oxidation of sulfides-atmospheric oxygen or oxidized forms of nitrogen. Different genera of sulfur-oxidizing bacteria and their technological application are discussed. PMID:25701621

  15. Utilization of 'elemental' sulfur by different phototrophic sulfur bacteria (Chromatiaceae, Ectothiorhodospiraceae): A sulfur K-edge XANES spectroscopy study

    International Nuclear Information System (INIS)

    Phototrophic sulfur bacteria are generally able to use elemental sulfur as an electron donor for anoxygenic photosynthesis. Elemental sulfur is mainly a mixture of cyclo-octasulfur and polymeric sulfur. The purple sulfur bacterium Allochromatium vinosum strongly prefers the polymeric sulfur fraction showing that sulfur speciation has a strong influence on availability of elemental sulfur. X-ray absorption near edge structure (XANES) spectroscopy was used to investigate whether polymeric sulfur is also the preferred sulfur species in other purple sulfur bacteria belonging to the families Chromatiaceae and Ecothiorodospiraceae. The cultures were fed with 50 mM of elemental sulfur consisting of 68% polymeric sulfur and 30% cyclo-octasulfur. In all cultures, elemental sulfur was converted into intra- or extracellular sulfur globules, respectively, and further oxidized to sulfate. Sulfate concentrations were determined by HPLC and turbidometric assays, respectively. However, the added elemental sulfur was only partly used by the bacteria, one part of the 'elemental sulfur' remained in the cultures and was not taken up. XANES spectroscopy revealed that only the polymeric sulfur fraction was taken up by all cultures investigated. This strongly indicates that polymeric 'chain-like' sulfur is the form preferably used by phototrophic sulfur bacteria.

  16. Reduction of malachite green to leucomalachite green by intestinal bacteria.

    Science.gov (United States)

    Henderson, A L; Schmitt, T C; Heinze, T M; Cerniglia, C E

    1997-10-01

    Intestinal microfloras from human, rat, mouse, and monkey fecal samples and 14 pure cultures of anaerobic bacteria representative of those found in the human gastrointestinal tract metabolized the triphenylmethane dye malachite green to leucomalachite green. The reduction of malachite green to the leuco derivative suggests that intestinal microflora could play an important role in the metabolic activation of the triphenylmethane dye to a potential carcinogen. PMID:9327576

  17. Influence of Purple Sulfur Bacteria on the biogeochemistry of Carbon and Sulfur Isotopes in Crystal Lake, OH

    Science.gov (United States)

    Meyer, A.; Nichols, D. L.; Cheng, S.

    2013-12-01

    Crystal Lakes are a series of four interconnected mesotrophic, moulin-induced glacial lakes in west-central Ohio. The study site, Main Lake (a.k.a. Crystal Lake), is the largest and deepest lake among them. It is about 5 ha with a maximum depth of 11.9 meters and a mean depth of 3.8 meters. Thermal stratification develops during the warmer months. Photosynthesis, which preferentially uptakes lighter isotopes, is the primary pathway for carbon and sulfur isotope fractionation in natural waters. Photosynthesizers present at Crystal Lake include green algae, diatoms, cyanobacteria, and purple sulfur bacteria (PSB). Phytoplankton growth is limited by nutrient availability, influencing the extent of fractionation. Purple sulfur bacteria (PSB) utilize sulfide as an electron donor instead of water. The layer of concentrated PSB population exists between oxic and anoxic water in lakes where sufficient light and sulfide are present. These bacteria impact the levels of several sulfur compounds and isotopic composition within lake systems by oxidizing sulfide to sulfate. Field parameters collected in warmer months show turbidity and chlorophyll peaks around 6 m with variations caused by temperature, light, and nutrient availability. The dissolved oxygen minimum and the redox and sulfate maxima generally correspond with the turbidity and chlorophyll peaks, indicating the presence of a PSB layer. This layer occurs at the boundary between the metalimnion and hypolimnion. Sulfide concentrations increased from a maximum of 0.02 mg/L in May to a maximum of 9.25 mg/L in August. In May sulfide was only found at 10.4 m and below while in August it was present at 6 m and below. Sulfate values remain relatively constant with a maximum at the layer of PSB, then decline with depth where Sulfide is abundant. ?13C-DIC values peak at 6 m corresponding with the layer of PSB. This peak may be due to the influence of PSB on carbon isotope fractionation. The carbon isotope composition of phytoplankton is to be determined. The isotopic composition of different sulfur species, SO42- , S0 and S2-, and seasonal variation are being analyzed. Exploration of the potential role of PSB on sulfur isotopic composition and their affect on the sulfur isotopic distribution in the lake system is in progress. Currently, no sulfur isotopic composition measurements through PSB or systematic studies of the impact of fractionation between sulfate and sulfide by PSB exist in the literature. Since PSB affect the equilibrium of the system, more than just sulfate and sulfide should be considered.

  18. Motility patterns of filamentous sulfur bacteria, Beggiatoa spp

    DEFF Research Database (Denmark)

    Dunker, Rita; Røy, Hans; Kamp, Anja; Jørgensen, Bo Barker

    2011-01-01

    The large sulfur bacteria, Beggiatoa spp., live on the oxidation of sulfide with oxygen or nitrate, but avoid high concentrations of both sulfide and oxygen. As gliding filaments, they rely on reversals in the gliding direction to find their preferred environment, the oxygen–sulfide interface. We observed the chemotactic patterns of single filaments in a transparent agar medium and scored their reversals and the glided distances between reversals. Filaments within the preferred microenvironment ...

  19. Motility patterns of filamentous sulfur bacteria, Beggiatoa spp

    DEFF Research Database (Denmark)

    Dunker, Rita; Røy, Hans; Kamp, Anja; Jørgensen, Bo Barker

    2011-01-01

    The large sulfur bacteria, Beggiatoa spp., live on the oxidation of sulfide with oxygen or nitrate, but avoid high concentrations of both sulfide and oxygen. As gliding filaments, they rely on reversals in the gliding direction to find their preferred environment, the oxygen–sulfide interface.We observed the chemotactic patterns of single filaments in a transparent agar medium and scored their reversals and the glided distances between reversals. Filaments within the preferred microenvironment g...

  20. Thioploca spp: filamentous sulfur bacteria with nitrate vacuoles

    DEFF Research Database (Denmark)

    JØrgensen, BB; Gallardo, VA

    1999-01-01

    Thioploca spp. are multicellular, filamentous, colorless sulfur bacteria inhabiting freshwater and marine sediments. They have elemental sulfur inclusions similar to the phylogenetically closely related Beggiatoa, but in contrast to these they live in bundles surrounded by a common sheath. Vast communities of large Thioploca species live along the Pacific coast of South America and in other upwelling areas of high organic matter sedimentation with bottom waters poor in oxygen and rich in nitrate. Each cell of these thioplocas harbors a large liquid vacuole which is used as a storage for nitrate with a concentration of lip to 506 mM. The nitrate is used as an electron acceptor for sulfide oxidation and the bacteria may grow autotrophically or mixotrophically using acetate or other organic molecules as carbon source. The filaments stretch up into the overlying seawater, from which they take up nitrate, and then glide down 5-15 cm deep into the sediment through their sheaths to oxidize sulfide formed by intensive sulfate reduction. New major occurrences have bren found in recent years, both in lakes and in the ocean, and have stimulated the interest in these fascinating bacteria. (C) 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.

  1. Nitrogen fixation by the thermophilic green sulfur bacterium Chlorobium tepidum.

    OpenAIRE

    Wahlund, T M; Madigan, M T

    1993-01-01

    The thermophilic green sulfur bacterium Chlorobium tepidum grew with N2, NH4+, or glutamine as the sole nitrogen source under phototrophic (anaerobic-light) conditions. Growth on N2 required increased buffering capacity to stabilize uncharacterized pH changes that occurred during diazotrophic growth. Increased sulfide levels were stimulatory for growth on N2. Levels of nitrogenase activity (acetylene reduction) in N2-grown C. tepidum cells were very high, among the highest ever reported for a...

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

    Directory of Open Access Journals (Sweden)

    Raffaele PEDUZZI

    2004-08-01

    Full Text Available 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 cells ml-1. The most abundant taxa in the chemocline are large- and small-celled purple sulfur bacteria, which account for up to 35% of all bacteria, and sulfate- reducing bacteria that represent up to 23% of all bacteria. Depending on the season, as much as 45% of all bacteria in the chemocline are associated in aggregates consisting of different populations of small-celled purple sulfur bacteria of the genus Lamprocystis (up to 35% of all bacteria and sulfate-reducing bacteria of the family Desulfobulbaceae (up to 12% of all bacteria that are almost completely represented by bacteria closely related to Desulfocapsa thiozymogenes. Their association in aggregates is restricted to small-celled purple sulfur bacteria of the genus Lamprocystis, but not obligate since non-associated cells of bacteria related to D. thiozymogenes are frequently found, especially under limited light conditions in winter and early summer. Aggregate formation and concomitant growth enhancement of isolates of both partners of this association suggests synergistic interactions that might resemble a sulfide-based source-sink relationship between the sulfate-reducing bacterium that is able to sustain growth by a disproportionation of inorganic sulfur compounds (sulfur, thiosulfate, sulfite, with the purple sulfur bacteria acting as a biotic scavenger. The availability of these isolates opens up the door for future studies considering other facets of potential interactions in aggregates since both types of organisms are metabolically highly versatile and interactions may not be limited to sulfur compounds only.

  3. Motility patterns of filamentous sulfur bacteria, Beggiatoa spp.

    DEFF Research Database (Denmark)

    Dunker, Rita; RØy, Hans

    2011-01-01

    The large sulfur bacteria, Beggiatoa spp., live on the oxidation of sulfide with oxygen or nitrate, but avoid high concentrations of both sulfide and oxygen. As gliding filaments, they rely on reversals in the gliding direction to find their preferred environment, the oxygen–sulfide interface.We observed the chemotactic patterns of single filaments in a transparent agar medium and scored their reversals and the glided distances between reversals. Filaments within the preferred microenvironment glided distances shorter than their own length between reversals that anchored them in their position as a microbial mat. Filaments in the oxic region above the mat or in the sulfidic, anoxic region below the mat glided distances longer than the filament length between reversals. This reversal behavior resulted in a diffusion-like spreading of the filaments. A numerical model of such gliding filaments was constructed based on our observations. The model was applied to virtual filaments in the oxygen- and sulfide-free zone of the sediment, which is a main habitat of Beggiatoa in the natural environment. The model predicts a long residence time of the virtual filament in the suboxic zone and explains why Beggiatoa accumulate high nitrate concentrations in internal vacuoles as an alternative electron acceptor to oxygen.

  4. Motility patterns of filamentous sulfur bacteria, Beggiatoa spp

    DEFF Research Database (Denmark)

    Dunker, Rita; RØy, Hans

    2011-01-01

    The large sulfur bacteria, Beggiatoa spp., live on the oxidation of sulfide with oxygen or nitrate, but avoid high concentrations of both sulfide and oxygen. As gliding filaments, they rely on reversals in the gliding direction to find their preferred environment, the oxygen–sulfide interface. We observed the chemotactic patterns of single filaments in a transparent agar medium and scored their reversals and the glided distances between reversals. Filaments within the preferred microenvironment glided distances shorter than their own length between reversals that anchored them in their position as a microbial mat. Filaments in the oxic region above the mat or in the sulfidic, anoxic region below the mat glided distances longer than the filament length between reversals. This reversal behavior resulted in a diffusion-like spreading of the filaments. A numerical model of such gliding filaments was constructed based on our observations. The model was applied to virtual filaments in the oxygen- and sulfide-free zone of the sediment, which is a main habitat of Beggiatoa in the natural environment. The model predicts a long residence time of the virtual filament in the suboxic zone and explains why Beggiatoa accumulate high nitrate concentrations in internal vacuoles as an alternative electron acceptor to oxygen.

  5. Purple non-sulfur photosynthetic bacteria monitor environmental stresses.

    Science.gov (United States)

    Kis, Mariann; Sipka, Gábor; Asztalos, Emese; Rázga, Zsolt; Maróti, Péter

    2015-10-01

    Heavy metal ion pollution and oxygen deficiency are major environmental risks for microorganisms in aqueous habitat. The potential of purple non-sulfur photosynthetic bacteria for biomonitoring and bioremediation was assessed by investigating the photosynthetic capacity in heavy metal contaminated environments. Cultures of bacterial strains Rhodobacter sphaeroides, Rhodospirillum rubrum and Rubrivivax gelatinosus were treated with heavy metal ions in micromolar (Hg(2+)), submillimolar (Cr(6+)) and millimolar (Pb(2+)) concentration ranges. Functional assays (flash-induced absorption changes and bacteriochlorophyll fluorescence induction) and electron micrographs were taken to specify the harmful effects of pollution and to correlate to morphological changes of the membrane. The bacterial strains and functional tests showed differentiated responses to environmental stresses, revealing that diverse mechanisms of tolerance and/or resistance are involved. The microorganisms were vulnerable to the prompt effect of Pb(2+), showed weak tolerance to Hg(2+) and proved to be tolerant to Cr(6+). The reaction center controlled electron transfer in Rvx. gelatinosus demonstrated the highest degree of resistance against heavy metal exposure. PMID:26232748

  6. Oxygen uncouples light absorption by the chlorosome antenna and photosynthetic electron transfer in the green sulfur bacterium Chlorobium tepidum

    DEFF Research Database (Denmark)

    Frigaard, N-U; Matsuura, K

    1999-01-01

    In photosynthetic green sulfur bacteria excitation energy is transferred from large bacteriochlorophyll (BChl) c chlorosome antennas via small BChl a antennas to the reaction centers which then transfer electrons from cytochrome c to low-potential iron-sulfur proteins. Under oxidizing conditions a reversible mechanism is activated in the chlorosomes which quenches excited BChl c. We used flash-induced cytochrome c oxidation to investigate the effect of this quenching on photosynthetic electron t...

  7. Roles of thioredoxins in the obligate anaerobic green sulfur photosynthetic bacterium Chlorobaculum tepidum.

    Science.gov (United States)

    Hosoya-Matsuda, Naomi; Inoue, Kazuhito; Hisabori, Toru

    2009-03-01

    Thioredoxin is a small ubiquitous protein that is involved in the dithiol-disulfide exchange reaction, by way of two cysteine residues located on the molecule surface. In order to elucidate the role of thioredoxin in Chlorobaculum tepidum, an anaerobic green sulfur bacterium that uses various inorganic sulfur compounds and H(2)S as electron donors under strict anaerobic conditions for growth, we applied the thioredoxin affinity chromatography method (Motohashi et al., 2001). In this study, 37 cytoplasmic proteins were captured as thioredoxin target candidates, including proteins involved in sulfur assimilation. Furthermore, six of the candidate proteins were members of the reductive tricarboxylic acid cycle (pyruvate orthophosphate dikinase, pyruvate flavodoxin/ferredoxin oxidoreductase, alpha-oxoglutarate synthase, citrate lyase, citrate synthase, malate dehydrogenase). The redox sensitivity of three enzymes was then examined: citrate lyase, citrate synthase, and malate dehydrogenase, using their recombinant proteins. Based on the information relating to the target proteins, the significance of thioredoxin as a reductant for the metabolic pathway in the anaerobic photosynthetic bacteria is discussed. PMID:19825618

  8. [Fe]-hydrogenases in green algae: photo-fermentation and hydrogen evolution under sulfur deprivation

    Energy Technology Data Exchange (ETDEWEB)

    Winkler, M.; Hemschemeier, A.; Happe, T. [Botanisches Institut der Universitat Bonn (Germany); Gotor, C. [CSIC y Universidad de Sevilla (Spain). Instituto de Bioquimica Vegetal y Fotosintesis; Melis, A. [University of California, Berkeley, CA (United States). Department of Plant and Microbial Biology

    2002-12-01

    Recent studies indicate that [Fe]-hydrogenases and H{sub 2} metabolism are widely distributed among green algae. The enzymes are simple structured and catalyze H{sub 2} evolution with similar rates than the more complex [Fe]-hydrogenases from bacteria. Different green algal species developed diverse strategies to survive under sulfur deprivation. Chlamydomonas reinhardtii evolves large quantities of hydrogen gas in the absence of sulfur. In a sealed culture of C. reinhardtii, the photosynthetic O{sub 2} evolution rate drops below the rate of respiratory O{sub 2} consumption due to a reversible inhibition of photosystem II, thus leading to an intracellular anaerobiosis. The algal cells survive under these anaerobic conditions by switching their metabolism to a kind of photo-fermentation. Although possessing a functional [Fe]-hydrogenase gene, the cells of Scenedesmus obliquus produce no significant amounts of H{sub 2} under S-depleted conditions. Biochemical analyses indicate that S. obliquus decreases almost the complete metabolic activities while maintaining a low level of respiratory activity. (author)

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

    Science.gov (United States)

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

    2001-01-01

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

  10. Reduction of hexavalent chromium with elemental sulfur by sulfur-oxidizing bacteria. Bakuteria ni yoru rokka kuromu no kangen ni kansuru kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Nakazawa, Hiroshi; Murata, Hiroyuki; Sato, Hayato (Iwate Univ., Iwate (Japan) Faculty of Engineering)

    1989-11-25

    The reduction of hexavalent chromium (Cr{sub 6+}) by use of sulfurous acid formed by sulfur-oxidizing bacteria was investigated. The test bacteria were collected from a neutralization plant at the abandoned Matsuo mine and cultured for long period in iron free 9K medium with elemental sulfur, then the experiment on the reduction of Cr{sup 6+} was conducted. The bacteria oxidized elemental sulfur to sulfate, and main strains of them must be Thiobacillus ferrooxidans and Thiobacillus thiooxidans. Cr{sup 6+} was reduced when the bacteria were cultured on elemental sulfur. It could be due to sulfurous acid formed as a intermediate during the oxidation of elemental sulfur to sulfate by the bacteria. Cr{sup 6+} inhibited the sulfur-oxidizing ability of the bacteria, but the oxidation rate of elemental sulfur increased remarkably after the reduction of Cr{sup 6+}. The rate of Cr{sup 6+} reduction increased with heightening the inoculum size and the concentration of elemental sulfur, and with lowering the pH. 14 refs., 8 figs.

  11. Redox regulation of energy transfer efficiency in antennas of green photosynthetic bacteria

    Science.gov (United States)

    Blankenship, R. E.; Cheng, P.; Causgrove, T. P.; Brune, D. C.; Wang, J.

    1993-01-01

    The efficiency of energy transfer from the peripheral chlorosome antenna structure to the membrane-bound antenna in green sulfur bacteria depends strongly on the redox potential of the medium. The fluorescence spectra and lifetimes indicate that efficient quenching pathways are induced in the chlorosome at high redox potential. The midpoint redox potential for the induction of this effect in isolated chlorosomes from Chlorobium vibrioforme is -146 mV at pH 7 (vs the normal hydrogen electrode), and the observed midpoint potential (n = 1) decreases by 60 mV per pH unit over the pH range 7-10. Extraction of isolated chlorosomes with hexane has little effect on the redox-induced quenching, indicating that the component(s) responsible for this effect are bound and not readily extractable. We have purified and partially characterized the trimeric water-soluble bacteriochlorophyll a-containing protein from the thermophilic green sulfur bacterium Chlorobium tepidum. This protein is located between the chlorosome and the membrane. Fluorescence spectra of the purified protein indicate that it also contains groups that quench excitations at high redox potential. The results indicate that the energy transfer pathway in green sulfur bacteria is regulated by redox potential. This regulation appears to operate in at least two distinct places in the energy transfer pathway, the oligomeric pigments in the interior of the chlorosome and in the bacteriochlorophyll a protein. The regulatory effect may serve to protect the cell against superoxide-induced damage when oxygen is present. By quenching excitations before they reach the reaction center, reduction and subsequent autooxidation of the low potential electron acceptors found in these organisms is avoided.

  12. Taurine-Sulfur Assimilation and Taurine-Pyruvate Aminotransferase Activity in Anaerobic Bacteria

    OpenAIRE

    Chien, C; Leadbetter, E. R.; Godchaux, W

    1997-01-01

    We demonstrated the ability of strictly fermentative, as well as facultatively fermentative, bacteria to assimilate sulfonate sulfur for growth. Taurine (2-aminoethanesulfonate) can be utilized by Clostridium pasteurianum C1 but does not support fermentative growth of two Klebsiella spp. and two different Clostridium spp. However, the latter are able to assimilate the sulfur of a variety of other sulfonates (e.g., cysteate, 3-sulfopyruvate, and 3-sulfolactate) anaerobically. A novel taurine-p...

  13. A reconstituted light-harvesting complex from the green sulfur bacterium Chlorobium tepidum containing CsmA and bacteriochlorophyll a

    DEFF Research Database (Denmark)

    Pedersen, Marie Ø; Pham, Lan; Steensgaard, Dorte B; Miller, Mette

    2008-01-01

    Green sulfur bacteria possess two light-harvesting antenna systems, the chlorosome and the Fenna-Matthews-Olson (FMO) protein. In addition to self-aggregated bacteriochlorophyll (BChl) c, chlorosomes of Chlorobium tepidum contain a small amount of BChl a (ratio 100:1). The chlorosomal BChl a is associated with CsmA, a 6.2 kDa protein that accounts for more than 50% of the protein content of chlorosomes. This CsmA-BChl a complex is located in the chlorosome baseplate with the hydrophilic C-termin...

  14. Microbial ecology of halo-alkaliphilic sulfur bacteria:

    OpenAIRE

    Foti, M.J.

    2007-01-01

    The research of this thesis focussed on the investigation of the microbial diversity in soda lakes, giving a special attention to the micro-organisms involved in the sulphur cycle. The present PhD was part of a bigger project aiming to develop a biological process for the removal of hydrogen sulphide under halo-alkaliphilic conditions. In this new process, sulphide is mainly oxidized to elemental sulphur by sulphur-oxidizing bacteria (SOB). However, a small percentage of unwanted sulphate is ...

  15. Phylogenetic Evidence for the Existence of Novel Thermophilic Bacteria in Hot Spring Sulfur-Turf Microbial Mats in Japan

    OpenAIRE

    Yamamoto, Hiroyuki; Hiraishi, Akira; Kato, Kenji; Chiura, Hiroshi X.; Maki, Yonosuke; Shimizu, Akira

    1998-01-01

    So-called sulfur-turf microbial mats, which are macroscopic white filaments or bundles consisting of large sausage-shaped bacteria and elemental sulfur particles, occur in sulfide-containing hot springs in Japan. However, no thermophiles from sulfur-turf mats have yet been isolated as cultivable strains. This study was undertaken to determine the phylogenetic positions of the sausage-shaped bacteria in sulfur-turf mats by direct cloning and sequencing of 16S rRNA genes amplified from the bulk...

  16. Population study of the filamentous sulfur bacteria Thioploca spp. off the Bay of Concepcion, Chile

    DEFF Research Database (Denmark)

    Schulz, HN; Strotmann, B.; Gallardo, VA; Jørgensen, BB

    2000-01-01

    A population of filamentous sulfur bacteria Thioploca spp. living in the Bay of Concepcion, Chile, and the adjoining shelf area was sampled for 14 mo at 4 to 6 wk intervals to investigate the influence of seasonal variations in upwelling intensity and oxygen concentrations on the population dynamics. The Thioploca population was described by its biomass, total number and diameter of sheaths, number of trichomes and species per sheath, and abundance and depth distribution of different morphologic...

  17. Application of bacteria involved in the biological sulfur cycle for paper mill effluent purification

    OpenAIRE

    Janssen, A. J. H.; Lens, P.N.L.; A. J. M. Stams; Plugge, C. M.; Sorokin, D. Y.; Muyzer, G.; Dijkman, H; Zessen, E., van; Luimes, F.J.T.; Buisman, C. J. N.

    2009-01-01

    In anaerobic wastewater treatment, the occurrence of biological sulfate reduction results in the formation of unwanted hydrogen sulfide, which is odorous, corrosive and toxic. In this paper, the role and application of bacteria in anaerobic and aerobic sulfur transformations are described and exemplified for the treatment of a paper mill wastewater. The sulfate containing wastewater first passes an anaerobic UASB reactor for bulk COD removal which is accompanied by the formation of biogas and...

  18. Insights into the genome of large sulfur bacteria revealed by analysis of single filaments

    DEFF Research Database (Denmark)

    Mussmann, Marc; Hu, Fen Z.

    2007-01-01

    Marine sediments are frequently covered by mats of the filamentous Beggiatoa and other large nitrate-storing bacteria that oxidize hydrogen sulfide using either oxygen or nitrate, which they store in intracellular vacuoles. Despite their conspicuous metabolic properties and their biogeochemical importance, little is known about their genetic repertoire because of the lack of pure cultures. Here, we present a unique approach to access the genome of single filaments of Beggiatoa by combining whole genome amplification, pyrosequencing, and optical genome mapping. Sequence assemblies were incomplete and yielded average contig sizes of approximately 1 kb. Pathways for sulfur oxidation, nitrate and oxygen respiration, and CO2 fixation confirm the chemolithoautotrophic physiology of Beggiatoa. In addition, Beggiatoa potentially utilize inorganic sulfur compounds and dimethyl sulfoxide as electron acceptors. We propose a mechanism of vacuolar nitrate accumulation that is linked to proton translocation by vacuolar-type ATPases. Comparative genomics indicates substantial horizontal gene transfer of storage, metabolic, and gliding capabilities between Beggiatoa and cyanobacteria. These capabilities enable Beggiatoa to overcome non-overlapping availabilities of electron donors and acceptors while gliding between oxic and sulfidic zones. The first look into the genome of these filamentous sulfur-oxidizing bacteria substantially deepens the understanding of their evolution and their contribution to sulfur and nitrogen cycling in marine sediments.

  19. An integrated method incorporating sulfur-oxidizing bacteria and electrokinetics to enhance removal of copper from contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Maini, G.; Sharman, A.K.; Sunderland, G.; Knowles, C.J.; Jackman, S.A.

    2000-03-15

    The combination of bioleaching and electrokinetics for the remediation of metal contaminated land has been investigated. In bioleaching, bacteria convert reduced sulfur compounds to sulfuric acid, acidifying soil and mobilizing metal ions. In electrokinetics, DC current acidifies soil, and mobilized metals are transported to the cathode by electromigration. When bioleaching was applied to silt soil artificially contaminated with seven metals and amended with sulfur, bacterial activity was partially inhibited and limited acidification occurred. Electrokinetic treatment of silt soil contaminated solely with 1000 mg/kg copper nitrate showed 89% removal of copper from the soil within 15 days. To combine bioleaching and electrokinetics sequentially, preliminary partial acidification was performed by amending copper-contaminated soil with sulfur (to 5% w/w) and incubating at constant moisture (30% w/w) and temperature (20 C) for 90 days. Indigenous sulfur oxidizing bacteria partially acidified the soil from pH 8.1 to 5.4. This soil was then treated by electrokinetics yielding 86% copper removal in 16 days. In the combined process, electrokinetics stimulated sulfur oxidation, by removing inhibitory factors, yielding a 5.1-fold increase in soil sulfate concentration. Preacidification by sulfur-oxidizing bacteria increased the cost-effectiveness of the electrokinetic treatment by reducing the power requirement by 66%.

  20. Population study of the filamentous sulfur bacteria Thioploca spp. off the Bay of Concepcion, Chile

    DEFF Research Database (Denmark)

    Schulz, HN; Strotmann, B.

    2000-01-01

    A population of filamentous sulfur bacteria Thioploca spp. living in the Bay of Concepcion, Chile, and the adjoining shelf area was sampled for 14 mo at 4 to 6 wk intervals to investigate the influence of seasonal variations in upwelling intensity and oxygen concentrations on the population dynamics. The Thioploca population was described by its biomass, total number and diameter of sheaths, number of trichomes and species per sheath, and abundance and depth distribution of different morphological forms, e.g. trichome diameters and ratios of cell-length to diameter. Throughout the summer of 1996, oxygen concentrations in the bottom water were near zero, nitrate was 10 to 20 mu M and the biomass was high, up to 160 g m(-2) wet weight without sheaths. During winter, the biomass declined due to higher oxygen concentrations under reduced upwelling intensity. The depth distribution of Thioploca spp, changed strongly with seasonal variations, but the population structure remained mainly unchanged. During the 'El Nino' event in 1998, with high oxygen and low primary production the biomass was very low. In the Bay of Concepcion 2 populations of filamentous sulfur bacteria were observed, filaments with short cells in sheaths, populating the upper 7 cm of the sediment, and filaments without sheaths living at the sediment surface.

  1. Metabolic adaptation and trophic strategies of soil bacteria—C1- metabolism and sulfur chemolithotrophy in Starkeya novella

    OpenAIRE

    UlrikeKappler

    2013-01-01

    The highly diverse and metabolically versatile microbial communities found in soil environments are major contributors to the global carbon, nitrogen, and sulfur cycles. We have used a combination of genome –based pathway analysis with proteomics and gene expression studies to investigate metabolic adaptation in a representative of these bacteria, Starkeya novella, which was originally isolated from agricultural soil. This bacterium was the first facultative sulfur chemolithoautotroph that wa...

  2. Transcriptome for Photobiological Hydrogen Production Induced by Sulfur Deprivation in the Green Alga Chlamydomonas reinhardtii? †

    OpenAIRE

    Nguyen, Anh Vu; Thomas-Hall, Skye R.; Malnoë, Alizée; Timmins, Matthew; Mussgnug, Jan H; Rupprecht, Jens; Kruse, Olaf; Hankamer, Ben; Schenk, Peer M.

    2008-01-01

    Photobiological hydrogen production using microalgae is being developed into a promising clean fuel stream for the future. In this study, microarray analyses were used to obtain global expression profiles of mRNA abundance in the green alga Chlamydomonas reinhardtii at different time points before the onset and during the course of sulfur-depleted hydrogen production. These studies were followed by real-time quantitative reverse transcription-PCR and protein analyses. The present work provide...

  3. EFFECT OF LIGNIN ON ENZYMATIC SACCHARIFICATION OF HARDWOOD AFTER GREEN LIQUOR AND SULFURIC ACID PRETREATMENTS

    OpenAIRE

    Douyong Min,; Hasan Jameel,; Vincent Chiang,; Hou-min Chang

    2012-01-01

    Red maple, sweet gum, trembling aspen, red alder, and Eucalyptus globulus samples were pretreated with dilute sulfuric acid and green liquor before enzymatic saccharification. Substrates showed different levels of delignification and sugar recovery, depending on the applied pretreatments and the syringaldehyde/vanillin ratio (S/V). Three major conclusions were drawn in this research. First, lignin is the greatest contributor to recalcitrance of hardwood to enzymatic saccharification. Second, ...

  4. Genetic manipulation of carotenoid biosynthesis in the green sulfur bacterium Chlorobium tepidum

    DEFF Research Database (Denmark)

    Frigaard, Niels-Ulrik; Maresca, Julia A; Yunker, Colleen E; Jones, A Daniel; Bryant, Donald A

    2004-01-01

    The green sulfur bacterium Chlorobium tepidum is a strict anaerobe and an obligate photoautotroph. On the basis of sequence similarity with known enzymes or sequence motifs, nine open reading frames encoding putative enzymes of carotenoid biosynthesis were identified in the genome sequence of C. tepidum, and all nine genes were inactivated. Analysis of the carotenoid composition in the resulting mutants allowed the genes encoding the following six enzymes to be identified: phytoene synthase (crt...

  5. Metabolic Flux Analysis of the Mixotrophic Metabolisms in the Green Sulfur Bacterium Chlorobaculum tepidum*

    OpenAIRE

    Feng, Xueyang; TANG, KUO-HSIANG; Blankenship, Robert E; Tang, Yinjie J.

    2010-01-01

    The photosynthetic green sulfur bacterium Chlorobaculum tepidum assimilates CO2 and organic carbon sources (acetate or pyruvate) during mixotrophic growth conditions through a unique carbon and energy metabolism. Using a 13C-labeling approach, this study examined biosynthetic pathways and flux distributions in the central metabolism of C. tepidum. The isotopomer patterns of proteinogenic amino acids revealed an alternate pathway for isoleucine synthesis (via citramalate synthase, CimA, CT0612...

  6. Archaea, Bacteria, and Sulfur-Cycling in a Shallow-Sea Hydrothermal Ecosystem

    Science.gov (United States)

    Amend, J. P.; Huang, C.; Amann, R.; Bach, W.; Meyerdierks, A.; Price, R. E.; Schubotz, F.; Summons, R. E.; Wenzhoefer, F.

    2009-12-01

    Deep-sea hydrothermal systems are windows to the marine subsurface biosphere. It often is overlooked, however, that their far more accessible shallow-sea counterparts can serve the same purpose. To characterize the extent, diversity, and activity of the subsurface microbial community in the shallow vent ecosystem near Panarea Island (Italy), sediment cores were analyzed with a broad array of analytical techniques. Vent fluid and sediment temperatures reached up to 135 °C, with pHs in porewaters generally measuring 5-6. Microsensor profiles marked a very sharp oxic-anoxic transition, and when coupled to pH and H2S profiles, pointed to aerobic sulfide oxidation. With increasing depth from the sediment-water interface, porewater analyses showed a decrease in sulfate levels from ~30 mM to thermophilic sulfate reducing and acidophilic sulfide oxidizing bacteria. Results from several sites also showed that with increasing depth and temperature, biomass abundance of archaea generally increased relative to that of bacteria. Lastly, DGGE fingerprinting and 16S rRNA clone libraries from several depths at Hot Lake revealed a moderate diversity of bacteria, dominated by Epsilonproteobacteria; this class is known to catalyze both sulfur reduction and oxidation reactions, and to mediate the formation of iron-sulfides, including framboidal pyrite. Archaeal sequences at Hot Lake are dominated by uncultured Thermoplasmatales, plus several sequences in the Korarchaeota.

  7. Effects of stress hormones on the production of volatile sulfur compounds by periodontopathogenic bacteria

    Scientific Electronic Library Online (English)

    Caroline Morini, Calil; Gisele Mattos, Oliveira; Karina, Cogo; Antonio Carlos, Pereira; Fernanda Klein, Marcondes; Francisco Carlos, Groppo.

    2014-06-11

    Full Text Available Little is known about the effects of stress hormones on the etiologic agents of halitosis. Thus, the aim of this study was to evaluate in vitro the effects of adrenaline (ADR), noradrenaline (NA) and cortisol (CORT) on bacteria that produce volatile sulfur compounds (VSC), the major gases responsibl [...] e for bad breath. Cultures of Fusobacterium nucleatum (Fn), Porphyromonas endodontalis (Pe), Prevotella intermedia (Pi) and Porphyromonas gingivalis (Pg) were exposed to 50 µM ADR, NA and CORT or equivalent volumes of sterile water as controls for 12 and 24 h. Growth was evaluated based on absorbance at 660 nm. Portable gas chromatography was used to measure VSC concentrations. Kruskal-Wallis and the Dunn post-hoc test were used to compare the groups. For Fn, ADR, NA and CORT significantly reduced bacterial growth after 12 h and 24 h (p 0.05). In the Pi cultures, ADR, NA and CORT increased H2S (p

  8. Dynamic transition of chemolithotrophic sulfur-oxidizing bacteria in response to amendment with nitrate in deposited marine sediments.

    Science.gov (United States)

    Aoyagi, Tomo; Kimura, Makoto; Yamada, Namiha; Navarro, Ronald R; Itoh, Hideomi; Ogata, Atsushi; Sakoda, Akiyoshi; Katayama, Yoko; Takasaki, Mitsuru; Hori, Tomoyuki

    2015-01-01

    Although environmental stimuli are known to affect the structure and function of microbial communities, their impact on the metabolic network of microorganisms has not been well investigated. Here, geochemical analyses, high-throughput sequencing of 16S rRNA genes and transcripts, and isolation of potentially relevant bacteria were carried out to elucidate the anaerobic respiration processes stimulated by nitrate (20 mM) amendment of marine sediments. Marine sediments deposited by the Great East Japan Earthquake in 2011 were incubated anaerobically in the dark at 25?C for 5 days. Nitrate in slurry water decreased gradually for 2 days, then more rapidly until its complete depletion at day 5; production of N2O followed the same pattern. From day 2 to 5, the sulfate concentration significantly increased and the sulfur content in solid-phase sediments significantly decreased. These results indicated that denitrification and sulfur oxidation occurred simultaneously. Illumina sequencing revealed the proliferation of known sulfur oxidizers, i.e., Sulfurimonas sp. and Chromatiales bacteria, which accounted for approximately 43.5% and 14.8% of the total population at day 5, respectively. These oxidizers also expressed 16S rRNA to a considerable extent, whereas the other microorganisms, e.g., iron(III) reducers and methanogens, became metabolically active at the end of the incubation. Extinction dilution culture in a basal-salts medium supplemented with sulfur compounds and nitrate successfully isolated the predominant sulfur oxidizers: Sulfurimonas sp. strain HDS01 and Thioalkalispira sp. strain HDS22. Their 16S rRNA genes showed 95.2-96.7% sequence similarity to the closest cultured relatives and they grew chemolithotrophically on nitrate and sulfur. Novel sulfur-oxidizing bacteria were thus directly involved in carbon fixation under nitrate-reducing conditions, activating anaerobic respiration processes and the reorganization of microbial communities in the deposited marine sediments. PMID:26042094

  9. Genetic transfer by conjugation in the thermophilic green sulfur bacterium Chlorobium tepidum.

    OpenAIRE

    Wahlund, T M; Madigan, M T

    1995-01-01

    The broad-host-range IncQ group plasmids pDSK519 and pGSS33 were transferred by conjugation from Escherichia coli into the thermophilic green sulfur bacterium Chlorobium tepidum. C. tepidum exconjugants expressed the kanamycin and ampicillin-chloramphenicol resistances encoded by pDSK519 and pGSS33, respectively. Ampicillin resistance was a particularly good marker for selection in C. tepidum. Both pDSK519 and pGSS33 were stably maintained in C. tepidum at temperatures below 42 degrees C and ...

  10. Development of a real-time PCR method for the detection of fossil 16S rDNA fragments of phototrophic sulfur bacteria in the sediments of Lake Cadagno.

    Science.gov (United States)

    Ravasi, D F; Peduzzi, S; Guidi, V; Peduzzi, R; Wirth, S B; Gilli, A; Tonolla, M

    2012-05-01

    Lake Cadagno is a crenogenic meromictic lake situated in the southern range of the Swiss Alps characterized by a compact chemocline that has been the object of many ecological studies. The population dynamics of phototrophic sulfur bacteria in the chemocline has been monitored since 1994 with molecular methods such as 16S rRNA gene clone library analysis. To reconstruct paleo-microbial community dynamics, we developed a quantitative real-time PCR methodology for specific detection of 16S rRNA gene sequences of purple and green sulfur bacteria populations from sediment samples. We detected fossil 16S rDNA of nine populations of phototrophic sulfur bacteria down to 9-m sediment depth, corresponding to about 9500 years of the lake's biogeological history. These results provide the first evidence for the presence of 16S rDNA of anoxygenic phototrophic bacteria in Holocene sediments of an alpine meromictic lake and indicate that the water column stratification and the bacterial plume were already present in Lake Cadagno thousands of years ago. The finding of Chlorobium clathratiforme remains in all the samples analyzed shows that this population, identified in the water column only in 2001, was already a part of the lake's biota in the past. PMID:22433067

  11. Comparative proteomics and activity of a green sulfur bacterium across the water column of Lake Cadagno, Switzerland.

    DEFF Research Database (Denmark)

    Habicht, Kirsten Silvia; Miller, Mette

    2011-01-01

    Primary production in the meromictic Lake Cadagno, Switzerland, is dominated by anoxygenic photosynthesis. The green sulfur bacterium Chlorobium clathratiforme is the dominant phototrophic organism in the lake, comprising more than half of the bacterial population, and its biomass increases 3.8-fold over the summer. Cells from four positions in the water column were used for comparative analysis of the Chl. clathratiforme proteome in order to investigate changes in protein composition in response to the chemical and physical gradient in their environment, with special focus on how the bacteria survive in the dark. Although metagenomic data are not available for Lake Cadagno, proteome analysis was possible based on the completely sequenced genome of an isolated strain of Chl. clathratiforme. Using LC-MS/MS we identified 1321 Chl. clathratiforme proteins in Lake Cadagno and quantitatively compared 621 of these in the four samples. Our results showed that compared with cells obtained from the photic zone, cells collected from the dark part of the water column had the same expression level of key enzymes involved in carbon metabolism and photosynthetic light harvesting. However, most proteins participating in nitrogen and sulfur metabolism were twofold less abundant in the dark. From the proteome analysis we were able to show that Chl. clathratiforme in the photic zone contains enzymes for fixation of N2 and the complete oxidation of sulfide to sulfate while these processes are probably not active in the dark. Instead we propose that Chl. clathratiforme cells in the dark part of the water column obtain energy for maintenance from the fermentation of polyglucose. Based on the observed protein compositions we have constructed possible pathways for C, N and S metabolism in Chl. clathratiforme.

  12. Comparative proteomics and activity of a green sulfur bacterium across the water column of Lake Cadagno, Switzerland

    DEFF Research Database (Denmark)

    Habicht, Kirsten S.; Miller, Mette

    2011-01-01

    Primary production in the meromictic Lake Cadagno, Switzerland, is dominated by anoxygenic photosynthesis. The green sulfur bacterium Chlorobium clathratiforme is the dominant phototrophic organism in the lake, comprising more than half of the bacterial population, and its biomass increases 3.8-fold over the summer. Cells from four positions in the water column were used for comparative analysis of the Chl. clathratiforme proteome in order to investigate changes in protein composition in response to the chemical and physical gradient in their environment, with special focus on how the bacteria survive in the dark. Although metagenomic data are not available for Lake Cadagno, proteome analysis was possible based on the completely sequenced genome of an isolated strain of Chl. clathratiforme. Using LC-MS/MS we identified 1321 Chl. clathratiforme proteins in Lake Cadagno and quantitatively compared 621 of these in the four samples. Our results showed that compared with cells obtained from the photic zone, cells collected from the dark part of the water column had the same expression level of key enzymes involved in carbon metabolism and photosynthetic light harvesting. However, most proteins participating in nitrogen and sulfur metabolism were twofold less abundant in the dark. From the proteome analysis we were able to show that Chl. clathratiforme in the photic zone contains enzymes for fixation of N2 and the complete oxidation of sulfide to sulfate while these processes are probably not active in the dark. Instead we propose that Chl. clathratiforme cells in the dark part of the water column obtain energy for maintenance from the fermentation of polyglucose. Based on the observed protein compositions we have constructed possible pathways for C, N and S metabolism in Chl. clathratiforme

  13. EFFECT OF LIGNIN ON ENZYMATIC SACCHARIFICATION OF HARDWOOD AFTER GREEN LIQUOR AND SULFURIC ACID PRETREATMENTS

    Directory of Open Access Journals (Sweden)

    Douyong Min,

    2012-02-01

    Full Text Available Red maple, sweet gum, trembling aspen, red alder, and Eucalyptus globulus samples were pretreated with dilute sulfuric acid and green liquor before enzymatic saccharification. Substrates showed different levels of delignification and sugar recovery, depending on the applied pretreatments and the syringaldehyde/vanillin ratio (S/V. Three major conclusions were drawn in this research. First, lignin is the greatest contributor to recalcitrance of hardwood to enzymatic saccharification. Second, a high S/V ratio is a useful indicator of high delignification during a pretreatment process. Third, green liquor pretreatment is a promising pretreatment method because of a high delignification degree and sugar recovery. In addition, xylan also contributes to the recalcitrance of hardwoods toward enzymatic saccharification.

  14. Green electricity production with living plants and bacteria in a fuel cell

    OpenAIRE

    Strik, D.P.B.T.B.; Hamelers, H.V.M.; Snel, J.F.H.; Buisman, C.J.N.

    2008-01-01

    The world needs sustainable, efficient, and renewable energy production. We present the plant microbial fuel cell (plant-MFC), a concept that exploits a bioenergy source in situ. In the plant-MFC, plants and bacteria were present to convert solar energy into green electricity. The principal idea is that plants produce rhizodeposits, mostly in the form of carbohydrates, and the bacteria convert these rhizodeposits into electrical energy via the fuel cell. Here, we demonstrated the proof of pri...

  15. Application of bacteria involved in the biological sulfur cycle for paper mill effluent purification

    Energy Technology Data Exchange (ETDEWEB)

    Janssen, Albert J.H. [Sub-department of Environmental Technology, Wageningen University, Wageningen (Netherlands); Shell Global Solutions Int. B.V., Amsterdam (Netherlands)], E-mail: albert.janssen@wur.nl; Lens, Piet N.L. [Sub-department of Environmental Technology, Wageningen University, Wageningen (Netherlands); Stams, Alfons J.M.; Plugge, Caroline M. [Laboratory of Microbiology, Wageningen University, Wageningen (Netherlands); Sorokin, Dimitri Y. [Department of Biotechnology, Delft (Netherlands); Institute of Microbiology, Russian Academy of Science, Moscow (Russian Federation); Muyzer, Gerard [Department of Biotechnology, Delft (Netherlands); Dijkman, Henk; Van Zessen, Erik [Paques B.V., Balk (Netherlands); Luimes, Peter [Industriewater Eerbeek B.V. Eerbeek (Netherlands); Buisman, Cees J.N. [Sub-department of Environmental Technology, Wageningen University, Wageningen (Netherlands)

    2009-02-01

    In anaerobic wastewater treatment, the occurrence of biological sulfate reduction results in the formation of unwanted hydrogen sulfide, which is odorous, corrosive and toxic. In this paper, the role and application of bacteria in anaerobic and aerobic sulfur transformations are described and exemplified for the treatment of a paper mill wastewater. The sulfate containing wastewater first passes an anaerobic UASB reactor for bulk COD removal which is accompanied by the formation of biogas and hydrogen sulfide. In an aeration pond, the residual COD{sub organic} and the formed dissolved hydrogen sulfide are removed. The biogas, consisting of CH{sub 4} (80-90 vol.%), CO{sub 2} (10-20 vol.%) and H{sub 2}S (0.8-1.2 vol.%), is desulfurised prior to its combustion in a power generator thereby using a new biological process for H{sub 2}S removal. This process will be described in more detail in this paper. Biomass from the anaerobic bioreactor has a compact granular structure and contains a diverse microbial community. Therefore, other anaerobic bioreactors throughout the world are inoculated with biomass from this UASB reactor. The sludge was also successfully used in investigation on sulfate reduction with carbon monoxide as the electron donor and the conversion of methanethiol. This shows the biotechnological potential of this complex reactor biomass.

  16. Application of bacteria involved in the biological sulfur cycle for paper mill effluent purification

    International Nuclear Information System (INIS)

    In anaerobic wastewater treatment, the occurrence of biological sulfate reduction results in the formation of unwanted hydrogen sulfide, which is odorous, corrosive and toxic. In this paper, the role and application of bacteria in anaerobic and aerobic sulfur transformations are described and exemplified for the treatment of a paper mill wastewater. The sulfate containing wastewater first passes an anaerobic UASB reactor for bulk COD removal which is accompanied by the formation of biogas and hydrogen sulfide. In an aeration pond, the residual CODorganic and the formed dissolved hydrogen sulfide are removed. The biogas, consisting of CH4 (80-90 vol.%), CO2 (10-20 vol.%) and H2S (0.8-1.2 vol.%), is desulfurised prior to its combustion in a power generator thereby using a new biological process for H2S removal. This process will be described in more detail in this paper. Biomass from the anaerobic bioreactor has a compact granular structure and contains a diverse microbial community. Therefore, other anaerobic bioreactors throughout the world are inoculated with biomass from this UASB reactor. The sludge was also successfully used in investigation on sulfate reduction with carbon monoxide as the electron donor and the conversion of methanethiol. This shows the biotechnological potential of this complex reactor biomass

  17. Carbon isotope fractionation by thermophilic phototrophic sulfur bacteria: evidence for autotrophic growth in natural populations

    Science.gov (United States)

    Madigan, M. T.; Takigiku, R.; Lee, R. G.; Gest, H.; Hayes, J. M.

    1989-01-01

    Purple phototrophic bacteria of the genus Chromatium can grow as either photoautotrophs or photoheterotrophs. To determine the growth mode of the thermophilic Chromatium species, Chromatium tepidum, under in situ conditions, we have examined the carbon isotope fractionation patterns in laboratory cultures of this organism and in mats of C. tepidum which develop in sulfide thermal springs in Yellowstone National Park. Isotopic analysis (13C/12C) of total carbon, carotenoid pigments, and bacteriochlorophyll from photoautotrophically grown cultures of C. tepidum yielded 13C fractionation factors near -20%. Cells of C. tepidum grown on excess acetate, wherein synthesis of the Calvin cycle enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase ribulose bisphosphate carboxylase) was greatly repressed, were isotopically heavier, fractionation factors of ca. -7% being observed. Fractionation factors determined by isotopic analyses of cells and pigment fractions of natural populations of C. tepidum growing in three different sulfide thermal springs in Yellowstone National Park were approximately -20%, indicating that this purple sulfur bacterium grows as a photoautotroph in nature.

  18. Filamentous sulfur bacteria, Beggiatoa spp., in arctic marine sediments (Svalbard, 79°N)

    DEFF Research Database (Denmark)

    JØrgensen, Bo Barker; Dunker, Rita

    2010-01-01

    Fjord sediments on the west coast of the arctic archipelago Svalbard were surveyed to understand whether large filamentous sulfur bacteria of the genus Beggiatoa thrive at seawater temperatures permanently near freezing. Two sediments had abundant populations of Beggiatoa, while at six sites, only sporadic occurrences were observed. We conclude that Beggiatoa, although previously unnoticed, are widespread in these arctic fjord sediments. Beggiatoa ranged in diameter from 2 to 52 ?m and, by those tested, stored nitrate in vacuoles at up to 260 mM. The 16S rRNA gene sequence of a 20-?m-wide filament is closely associated with other large, marine, nitrate-storing Beggiatoa. The Beggiatoa mostly occurred in the upper 2-5 cm of oxidized surface sediment between oxygen and the deeper sulfidic zone. In spite of a very low or an undetectable sulfide concentration, sulfate reduction provided abundant H2S in this zone. The total living biomass of Beggiatoa filaments at one study site varied over 3 years between 1.13 and 3.36 g m-2. Because of their large size, Beggiatoa accounted for up to 15% of the total prokaryotic biomass, even though the filament counts at this site were rather low, comprising <1/10 000 of the bacterial numbers on a cell basis.

  19. Sedimentary sulfur geochemistry of the Paleogene Green River Formation, western USA: Implications for interpreting depositional and diagenetic processes in saline alkaline lakes

    Science.gov (United States)

    Tuttle, Michele L.; Goldhaber, Martin B.

    1993-07-01

    The sulfur geochemistry of the lacustrine Paleogene Green River Formation (Colorado, Utah, and Wyoming, USA) is unlike that of most marine and other lacustrine rocks. Distinctive chemical, isotopic, and mineralogical characteristics of the formation are pyrrhotite and marcasite, high contents of iron mineral sulfides strikingly enriched in 34S, cyclical trends in sulfur abundance and ? 34S values, and long-term evolutionary trends in ? 34S values. Analyses that identified and quantified these characteristics include carbonate-free abundance of organic carbon (0.13-47 wt%), total iron (0.31-13 wt%), reactive iron (>70% of total iron), total sulfur (0.02-16 wt%), acid-volatile monosulfide (S Av), disulfide (S Di > 70% of total sulfur), sulfate (S SO4) and organosulfur (S Org); isotopic composition of separated sulfur phases (? 34S Di,Av up to +49‰); and mineralogy, morphology and paragenesis of sulfide minerals. Mineralogy, morphology, ? 34S Di,Av, and ? 34S Org have a distinctive relation, reflecting variable and unique depositional and early diagenetic conditions in the Green River lakes. When the lakes were brackish, dissimilatory sulfate-reducing bacteria in the sediment produced H 2S, which initially reacted with labile iron to form pyrite framboids and more gradually with organic matter to form organosulfur compounds. During a long-lived stage of saline lake water, the amount of sulfate supplied by inflow decreased and alkalinity and pH of lake waters increased substantially. Extensive bacterial sulfate reduction in the water column kept lake waters undersaturated with sulfate minerals. A very high H 2S:SO 4 ratio developed in stagnant bottom water aided by the high pH that kinetically inhibited iron sulfidization. Progressive removal of H 2S by coeval formation of iron sulfides and organosulfur compounds caused the isotopic composition of the entire dissolved sulfur reservoir to evolve to ? 34S values much greater than that of inflow sulfate, which is estimated to have been +20‰ A six-million-year interval within Lake Uinta cores records this evolution as well as smaller systematic changes in ? 34S, interpreted to reflect ~ 100,000-year lake-level cycles. When porewater was exceptionally reducing, unstable FeS phases eventually recrystallized to pyrrhotite during diagenesis. A much later reaction related to weathering altered pyrrhotite to marcasite.

  20. Green ruthenium(4) sulfate forming under electrochemical dissolution of Fe-Ru-S alloys in sulfuric acid solution

    International Nuclear Information System (INIS)

    Methods of gel-chromatography, spectrophotometry and redox reactions were used to study green ruthenium(4) sulfate, forming in sulfuric acid solutions under electrochemical dissolution of Fe-Ru-S alloys at Ea 1.7 V. 16 refs.; 2 figs

  1. Isolation of lactic acid bacteria for its possible use in the fermentation of green algerian olives

    Directory of Open Access Journals (Sweden)

    Nour-Eddine, Karam

    2004-12-01

    Full Text Available This study was undertaken with the aim of obtaining lactic acid bacteria with the ability to ferment olives for possible use as starter cultures. For this reason, 32 isolates of lactic acid bacteria isolated from the spontaneous fermentation of green olives were characterized and identified on the basis of morphological and biochemical criteria. 14 of them were identified as Lactococcus lactis, 11 isolates as Lactobacillus plantarum and 7 isolates as Enterococcus sp. Of the 18 isolates examined for antagonistic activity, 3 isolates of Lactobacillus plantarum and one isolate of Enterococcus sp. were able to give distinct zones of inhibition against 5 indicator strains of lactic acid bacteria isolated in this study. Cell free supernatant of Lactobacillus plantarum OL9 was active against Gram-positive bacteria (Lactobacillus, Enterococcus and Propionibacterium and also against one Gram-negative bacteria strain of spoilage significance (Erwinia.Este estudio se emprendió con el objetivo de obtener bacterias del ácido láctico con capacidad para utilizarse como cultivo iniciador en la fermentación de aceitunas. Por esta razón, 32 cepas de bacterias del ácido láctico procedentes de fermentaciones espontáneas de aceitunas verdes se caracterizaron e identificaron en función de criterios morfológicos y bioquímicos. Catorce cepas se identificaron como Lactococcus lactis, 11 cepas como Lactobacillus plantarum y 7 cepas como Enterococcus sp. De las 18 cepas que se examinaron para detectar actividades antagónicas, se encontró que 3 cepas de Lactobacillus plantarum y una de Enterococcus sp. mostraban zonas de inhibición contra 5 cepas indicadoras de bacterias del ácido láctico aisladas en este estudio. El sobrenadante libre de células Lactobacillus plantarum OL9 fue activo contra diversas bacterias Gram-positivas (Lactobacillus, Enterococcus y Propionibacterium y contra una cepa de bacteria Gram-negativa relacionada con alteraciones (Erwinia.

  2. Isotopically labeled sulfur compounds and synthetic selenium and tellurium analogues to study sulfur metabolism in marine bacteria

    Directory of Open Access Journals (Sweden)

    Nelson L. Brock

    2013-05-01

    Full Text Available Members of the marine Roseobacter clade can degrade dimethylsulfoniopropionate (DMSP via competing pathways releasing either methanethiol (MeSH or dimethyl sulfide (DMS. Deuterium-labeled [2H6]DMSP and the synthetic DMSP analogue dimethyltelluriopropionate (DMTeP were used in feeding experiments with the Roseobacter clade members Phaeobacter gallaeciensis DSM 17395 and Ruegeria pomeroyi DSS-3, and their volatile metabolites were analyzed by closed-loop stripping and solid-phase microextraction coupled to GC–MS. Feeding experiments with [2H6]DMSP resulted in the incorporation of a deuterium label into MeSH and DMS. Knockout of relevant genes from the known DMSP demethylation pathway to MeSH showed in both species a residual production of [2H3]MeSH, suggesting that a second demethylation pathway is active. The role of DMSP degradation pathways for MeSH and DMS formation was further investigated by using the synthetic analogue DMTeP as a probe in feeding experiments with the wild-type strain and knockout mutants. Feeding of DMTeP to the R. pomeroyi knockout mutant resulted in a diminished, but not abolished production of demethylation pathway products. These results further corroborated the proposed second demethylation activity in R. pomeroyi. Isotopically labeled [2H3]methionine and 34SO42?, synthesized from elemental 34S8, were tested to identify alternative sulfur sources besides DMSP for the MeSH production in P. gallaeciensis. Methionine proved to be a viable sulfur source for the MeSH volatiles, whereas incorporation of labeling from sulfate was not observed. Moreover, the utilization of selenite and selenate salts by marine alphaproteobacteria for the production of methylated selenium volatiles was explored and resulted in the production of numerous methaneselenol-derived volatiles via reduction and methylation. The pathway of selenate/selenite reduction, however, proved to be strictly separated from sulfate reduction.

  3. Tetrazolium Reduction-Malachite Green Method for Assessing the Viability of Filamentous Bacteria in Activated Sludge

    OpenAIRE

    Bitton, Gabriel; Koopman, Ben

    1982-01-01

    A method was developed to assess the activity of filamentous bacteria in activated sludge. It involves the incubation of activated sludge with 2(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride followed by staining with malachite green. Both cells and 2(p-iodophenyl)-3-(p-nitrophenyl)-5-phenyl tetrazolium chloride-formazan crystals can be observed in prepared specimens by using bright-field microscopy. This procedure allowed us to distinguish between inactive and actively metabol...

  4. Predictive and Interpretive Simulation of Green Fluorescent Protein Expression in Reporter Bacteria

    OpenAIRE

    Leveau, Johan H J; Lindow, Steven E.

    2001-01-01

    We have formulated a numerical model that simulates the accumulation of green fluorescent protein (GFP) in bacterial cells from a generic promoter-gfp fusion. The model takes into account the activity of the promoter, the time it takes GFP to mature into its fluorescent form, the susceptibility of GFP to proteolytic degradation, and the growth rate of the bacteria. From the model, we derived a simple formula with which promoter activity can be inferred easily and quantitatively from actual me...

  5. Sulfur Oxygenase Reductase (Sor in the Moderately Thermoacidophilic Leaching Bacteria: Studies in Sulfobacillus thermosulfidooxidans and Acidithiobacillus caldus

    Directory of Open Access Journals (Sweden)

    Claudia Janosch

    2015-10-01

    Full Text Available The sulfur oxygenase reductase (Sor catalyzes the oxygen dependent disproportionation of elemental sulfur, producing sulfite, thiosulfate and sulfide. Being considered an “archaeal like” enzyme, it is also encoded in the genomes of some acidophilic leaching bacteria such as Acidithiobacillus caldus, Acidithiobacillus thiooxidans, Acidithiobacillus ferrivorans and Sulfobacillus thermosulfidooxidans, among others. We measured Sor activity in crude extracts from Sb. thermosulfidooxidans DSM 9293T. The optimum temperature for its oxygenase activity was achieved at 75 °C, confirming the “thermophilic” nature of this enzyme. Additionally, a search for genes probably involved in sulfur metabolism in the genome sequence of Sb. thermosulfidooxidans DSM 9293T was done. Interestingly, no sox genes were found. Two sor genes, a complete heterodisulfidereductase (hdr gene cluster, three tetrathionate hydrolase (tth genes, three sulfide quinonereductase (sqr, as well as the doxD component of a thiosulfate quinonereductase (tqo were found. Seven At. caldus strains were tested for Sor activity, which was not detected in any of them. We provide evidence that an earlier reported Sor activity from At. caldus S1 and S2 strains most likely was due to the presence of a Sulfobacillus contaminant.

  6. CO2 assimilation in the chemocline of Lake Cadagno is dominated by a few types of phototrophic purple sulfur bacteria

    DEFF Research Database (Denmark)

    Storelli, Nicola; Peduzzi, Sandro; Saad, Maged; Frigaard, Niels-Ulrik; Perret, Xavier; Tonolla, Mauro

    2013-01-01

    Lake Cadagno is characterized by a compact chemocline that harbors high concentrations of various phototrophic sulfur bacteria. Four strains representing the numerically most abundant populations in the chemocline were tested in dialysis bags in situ for their ability to fix CO?. The purple sulfur bacterium Candidatus 'Thiodictyon syntrophicum' strain Cad16(T) had the highest CO? assimilation rate in the light of the four strains tested and had a high CO? assimilation rate even in the dark. The ...

  7. Iron minerals formed by dissimilatory iron-and sulfur reducing bacteria studied by Mössbauer spectrometry

    Science.gov (United States)

    Chistyakova, N. I.; Rusakov, V. S.; Nazarova, K. A.; Koksharov, Yu. A.; Zavarzina, D. G.; Greneche, J.-M.

    2008-02-01

    Zero-field and in-field Mössbauer investigations and electron paramagnetic resonance (EPR) measurements to follow the kinetics of the iron mineral formation by thermophilic dissimilatory anaerobic Fe(III)-reducing bacteria (strain Z-0001) and anaerobic alkaliphilic bacteria (strain Z-0531) were carried out.

  8. Iron minerals formed by dissimilatory iron-and sulfur reducing bacteria studied by Moessbauer spectrometry

    International Nuclear Information System (INIS)

    Zero-field and in-field Moessbauer investigations and electron paramagnetic resonance (EPR) measurements to follow the kinetics of the iron mineral formation by thermophilic dissimilatory anaerobic Fe(III)-reducing bacteria (strain Z-0001) and anaerobic alkaliphilic bacteria (strain Z-0531) were carried out.

  9. Comparative proteomics and activity of a green sulfur bacterium across the water column of Lake Cadagno, Switzerland

    DEFF Research Database (Denmark)

    Habicht, Kirsten Silvia; Miller, Mette; Cox, Raymond Pickett; Frigaard, Niels-Ulrik; Tonolla, Mauro; Peduzzi, Sandro; Falkenby, Lasse Gaarde; Andersen, Jens S.

    2011-01-01

    Primary production in the meromictic Lake Cadagno, Switzerland, is dominated by anoxygenic photosynthesis. The green sulfur bacterium Chlorobium clathratiforme is the dominant phototrophic organism in the lake, comprising more than half of the bacterial population, and its biomass increases 3.8-fold over the summer. Cells from four positions in the water column were used for comparative analysis of the Chl. clathratiforme proteome in order to investigate changes in protein composition in respons...

  10. Selection of oleuropein-degrading lactic acid bacteria strains isolated from fermenting Moroccan green olives

    Energy Technology Data Exchange (ETDEWEB)

    Ghabbour, N.; Lamzira, Z.; Thonart, P.; Cidalia, P.; Markaouid, M.; Asehraoua, A.

    2011-07-01

    A total of 177 strains of lactic acid bacteria (LAB) were isolated from early-stage Moroccan Picholine green olive fermentation, including Lactobacillus plantarum (44.63%), Lactobacillus pentosus (25.99%), Lactobacillus brevis (9.61%) and Pediococcus pentosaceus (19.77%). All the isolates were screened for their tolerance to olive leaf extract and oleuropein. Most of the isolates (85.3%) were found able to degrade oleuropein, when evaluated by either oleuropein or 5-Bromo-4-chloro-3-indolyl {beta}-D-glucuronide (X-Gluc) as substrates. The biodegradation capacity of the selected strains of each species was confirmed by HPLC analysis. (Author).

  11. Selection of oleuropein-degrading lactic acid bacteria strains isolated from fermenting Moroccan green olives

    International Nuclear Information System (INIS)

    A total of 177 strains of lactic acid bacteria (LAB) were isolated from early-stage Moroccan Picholine green olive fermentation, including Lactobacillus plantarum (44.63%), Lactobacillus pentosus (25.99%), Lactobacillus brevis (9.61%) and Pediococcus pentosaceus (19.77%). All the isolates were screened for their tolerance to olive leaf extract and oleuropein. Most of the isolates (85.3%) were found able to degrade oleuropein, when evaluated by either oleuropein or 5-Bromo-4-chloro-3-indolyl ?-D-glucuronide (X-Gluc) as substrates. The biodegradation capacity of the selected strains of each species was confirmed by HPLC analysis. (Author).

  12. Isolation of Sulfur Reducing and Oxidizing Bacteria Found in Contaminated Drywall

    OpenAIRE

    Frederick T. Guilford; Sutton, John S.; Kilburn, Kaye H; Vincent Bolton; John Shane; Straus, David C; Hooper, Dennis G.

    2010-01-01

    Drywall from China has been reported to release sulfur producing products which are corrosive to metals, result in noxious odors, and represent a significant health risk. It has been reported that these emissions produce medical symptoms such as respiratory or asthma type problems, sinusitis, gastrointestinal disorders, and vision problems in home owners and their household pets. We report here a method of identifying a causative agent for these emissions by sampling affected gypsum wallboard...

  13. Metabolic flux analysis of the mixotrophic metabolisms in the green sulfur bacterium Chlorobaculum tepidum.

    Science.gov (United States)

    Feng, Xueyang; Tang, Kuo-Hsiang; Blankenship, Robert E; Tang, Yinjie J

    2010-12-10

    The photosynthetic green sulfur bacterium Chlorobaculum tepidum assimilates CO(2) and organic carbon sources (acetate or pyruvate) during mixotrophic growth conditions through a unique carbon and energy metabolism. Using a (13)C-labeling approach, this study examined biosynthetic pathways and flux distributions in the central metabolism of C. tepidum. The isotopomer patterns of proteinogenic amino acids revealed an alternate pathway for isoleucine synthesis (via citramalate synthase, CimA, CT0612). A (13)C-assisted flux analysis indicated that carbons in biomass were mostly derived from CO(2) fixation via three key routes: the reductive tricarboxylic acid (RTCA) cycle, the pyruvate synthesis pathway via pyruvate:ferredoxin oxidoreductase, and the CO(2)-anaplerotic pathway via phosphoenolpyruvate carboxylase. During mixotrophic growth with acetate or pyruvate as carbon sources, acetyl-CoA was mainly produced from acetate (via acetyl-CoA synthetase) or citrate (via ATP citrate lyase). Pyruvate:ferredoxin oxidoreductase converted acetyl-CoA and CO(2) to pyruvate, and this growth-rate control reaction is driven by reduced ferredoxin generated during phototrophic growth. Most reactions in the RTCA cycle were reversible. The relative fluxes through the RTCA cycle were 80?100 units for mixotrophic cultures grown on acetate and 200?230 units for cultures grown on pyruvate. Under the same light conditions, the flux results suggested a trade-off between energy-demanding CO(2) fixation and biomass growth rate; C. tepidum fixed more CO(2) and had a higher biomass yield (Y(X/S), mole carbon in biomass/mole substrate) in pyruvate culture (Y(X/S) = 9.2) than in acetate culture (Y(X/S) = 6.4), but the biomass growth rate was slower in pyruvate culture than in acetate culture. PMID:20937805

  14. Exploring bacteria-induced growth and morphogenesis in the green macroalga order Ulvales (Chlorophyta)

    Science.gov (United States)

    Wichard, Thomas

    2015-01-01

    Green macroalgae, such as Ulvales, lose their typical morphology completely when grown under axenic conditions or in the absence of the appropriate microbiome. As a result, slow growing aberrant phenotypes or even callus-like morphotypes are observed in Ulvales. The cross-kingdom interactions between marine algae and microorganisms are hence not only restricted by the exchange of macronutrients, including vitamins and nutrients, but also by infochemicals such as bacterial morphogenetic compounds. The latter are a fundamental trait mediating the mutualism within the chemosphere where the organisms interact with each other via compounds in their surroundings. Approximately 60 years ago, pilot studies demonstrated that certain bacteria promote growth, whereas other bacteria induce morphogenesis; this is particularly true for the order of Ulvales. However, only slow progress was made towards the underlying mechanism due to the complexity of, for example, algal cultivation techniques, and the lack of standardized experiments in the laboratory. A breakthrough in this research was the discovery of the morphogenetic compound thallusin, which was isolated from an epiphytic bacterium and induces normal germination restoring the foliaceous morphotypes of Monostroma. Owing to the low concentration, the purification and structure elucidation of highly biologically active morphogenetic compounds are still challenging. Recently, it was found that only the combination of two specific bacteria from the Rhodobacteraceae and Flavobacteriaceae can completely recover the growth and morphogenesis of axenic Ulva mutabilis cultures forming a symbiotic tripartite community by chemical communication. This review combines literature detailing evidences of bacteria-induced morphogenesis in Ulvales. A set of standardized experimental approaches is further proposed for the preparation of axenic algal tissues, bacteria isolation, co-cultivation experiments, and the analysis of the chemosphere. PMID:25784916

  15. Existing and emerging technologies that exploit sulfur cycling bacteria in subsurface petroleum reservoir microbial communities (Invited)

    Science.gov (United States)

    Hubert, C. R.

    2013-12-01

    Fossil fuels remain by far our most important energy resources, providing around 90% of global primary energy supply. In the coming decadal transition between petroleum reliance and a more sustainable energy future we must increasingly view our vital petroleum reserves as microbial ecosystems that can be engineered to responsibly and creatively meet the energy needs of societies worldwide. In this way, the bioenergy agenda must interface with the traditional geoenergy industry and the challenges it faces. Bioengineering and deep biosphere geomicrobiology focus on the ecophysiology and biogeography of microorganisms in subsurface habitats including marine sediments and petroleum reservoirs. Understanding microbial communities in fossil fuel deposits will allow their distribution and catalytic potential to be exploited as geobiotechnologies that target known problem areas including sulfur cycle management related to biodesulfurization of heavy oils and reservoir souring control via nitrate injection, as well as promising emerging directions such as understanding subsurface geofluid dispersal vectors that could enable microbes to be used as bio-indicators in offshore oil and gas exploration. Results related to different research themes within contemporary petroleum geomicrobiology and bioengineering at Newcastle University will be presented with a focus on microorganisms involved in sulfur cycling that are commonly detected in different oil field microbial communities including mesophilic sulfide-oxidizing Epsilonproteobacteria and thermophilic sulfate-reducers belonging to the genus Desulfotomaculum.

  16. Anaerobic sulfide-oxidation in marine colorless sulfur-oxidizing bacteria

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.; Nair, S.; Chandramohan, D.

    ). Experiments under increased pressure were conducted using hydraulic pressure chambers manufactured by Tsurumi Seiki Co. Glass vials (2.5 ml) with suitable rubber bungs were used for all experiments conducted under pressure. Experiments were replicated... Loka Bharathi PA (1989) The occurrence of denitrifying colourless sulphur- could become better adapted to these stress factors. Inorganic oxidising bacteria in marine waters and sediments as shown by the agar salts such as sodium chloride were the most...

  17. Carbon isotope fractionation by thermophilic phototrophic sulfur bacteria: evidence for autotrophic growth in natural populations.

    OpenAIRE

    Madigan, M T; Takigiku, R; Lee, R G; Gest, H.; Hayes, J M

    1989-01-01

    Purple phototrophic bacteria of the genus Chromatium can grow as either photoautotrophs or photoheterotrophs. To determine the growth mode of the thermophilic Chromatium species, Chromatium tepidum, under in situ conditions, we have examined the carbon isotope fractionation patterns in laboratory cultures of this organism and in mats of C. tepidum which develop in sulfide thermal springs in Yellowstone National Park. Isotopic analysis (13C/12C) of total carbon, carotenoid pigments, and bacter...

  18. Molecular Characterization of Novel Red Green Nonsulfur Bacteria from Five Distinct Hot Spring Communities in Yellowstone National Park

    OpenAIRE

    Boomer, Sarah M.; Lodge, Daniel P.; DUTTON, BRYAN E.; Pierson, Beverly

    2002-01-01

    We characterized and compared five geographically isolated hot springs with distinct red-layer communities in Yellowstone National Park. Individual red-layer communities were observed to thrive in temperatures ranging from 35 to 60°C and at pH 7 to 9. All communities were dominated by red filamentous bacteria and contained bacteriochlorophyll a (Bchl a), suggesting that they represented novel green nonsulfur (GNS) bacteria. The in vivo absorption spectra of individual sites were different, wi...

  19. Synergy in Sulfur Cycle: The Biogeochemical Significance of Sulfate Reducing Bacteria in Syntrophic Associations

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.

    in the form of red water. Therefore, the occurrence of the bacterial red water phenomenon is rather an effect than a cause for precedent organic pollution. Without the intervention of the microorganisms the region would continue to remain toxic... DMSP. DMSP could release DMS by the intervention of SRB. This is known to have counter effective effect on global warming but also the potent green house gas methane (van der Maarel and Hansen, 1997). Extracts of Desulfovibrio acrylicus from anoxic...

  20. Rhizosphere heterogeneity shapes abundance and activity of sulfur-oxidizing bacteria in vegetated salt marsh sediments

    Directory of Open Access Journals (Sweden)

    FrançoisThomas

    2014-06-01

    Full Text Available Salt marshes are highly productive ecosystems hosting an intense sulfur (S cycle, yet little is known about S-oxidizing microorganisms in these ecosystems. Here, we studied the diversity and transcriptional activity of S-oxidizers in salt marsh sediments colonized by the plant Spartina alterniflora, and assessed variations with sediment depth and small-scale compartments within the rhizosphere. We combined next-generation amplicon sequencing of 16S rDNA and rRNA libraries with phylogenetic analyses of marker genes for two S-oxidation pathways (soxB and rdsrAB. Gene and transcript numbers of soxB and rdsrAB phylotypes were quantified simultaneously, using newly designed (RT-qPCR assays. We identified a diverse assemblage of S-oxidizers, with Chromatiales and Thiotrichales being dominant. The detection of transcripts from S-oxidizers was mostly confined to the upper 5 cm sediments, following the expected distribution of root biomass. A common pool of species dominated by Gammaproteobacteria transcribed S-oxidation genes across roots, rhizosphere, and surrounding sediment compartments, with rdsrAB transcripts prevailing over soxB. However, the root environment fine-tuned the abundance and transcriptional activity of the S-oxidizing community. In particular, the global transcription of soxB was higher on the roots compared to mix and rhizosphere samples. Furthermore, the contribution of Epsilonproteobacteria-related S-oxidizers tended to increase on Spartina roots compared to surrounding sediments. These data shed light on the under-studied oxidative part of the sulfur cycle in salt marsh sediments and indicate small-scale heterogeneities are important factors shaping abundance and potential activity of S-oxidizers in the rhizosphere.

  1. Transient electron paramagnetic resonance spectroscopy on green-sulfur bacteria and heliobacteria at two microwave frequencies.

    Science.gov (United States)

    van der Est, A; Hager-Braun, C; Leibl, W; Hauska, G; Stehlik, D

    1998-12-01

    Spin polarized transient EPR spectra taken at X-band (9 GHz) and K-band (24 GHz) of membrane fragments of Chlorobium tepidum and Heliobacillus mobilis are presented along with the spectra of two fractions obtained in the purification of reaction centers (RC) from C. tepidum. The lifetime of P+. is determined by measuring the decay of the EPR signals following relaxation of the initial spin polarization. All samples except one of the RC fractions show evidence of light induced charge separation and formation of chlorophyll triplet states. The lifetime of P+. is found to be biexponential with components of 1.5 ms and 30 ms for C. tepidum and 1.0 and 4.5 ms for Hc. mobilis at 100 K. In both cases, the rates are assigned to recombination from F-X. The spin polarized radical pair spectra for both species are similar and those from Hc. mobilis at room temperature and 100 K are identical. In all cases, an emission/absorption polarization pattern with a net absorption is observed. A slight narrowing of the spectra and a larger absorptive net polarization is found at K-band. No out-of-phase echo modulation is observed. Taken together, the recombination kinetics, the frequency dependence of the spin polarization and the absence of an out-of-phase echo signal lead to the assignment of the spectra to the contribution from P+. to the state P+.F-X. The origin of the net polarization and its frequency dependence are discussed in terms of singlet-triplet mixing in the precursor. It is shown that the field-dependent polarization expected to develop during the 600-700 ps lifetime of P+.A-.0 is in qualitative agreement with the observed spectra. The identity that the acceptor preceding FX and the conflicting evidence from EPR, optical methods and chemical analyses of the samples are discussed. PMID:9838060

  2. Theoretical characterization of excitation energy transfer in chlorosome light-harvesting antennae from green sulfur bacteria

    CERN Document Server

    Fujita, Takatoshi; Saikin, Semion K; Brookes, Jennifer C; Aspuru-Guzik, Alan

    2013-01-01

    Chlorosomes are the largest and most efficient natural light-harvesting antenna systems. They contain thousands of pigment molecules - bacteriochlorophylls (BChls)- that are organized into supramolecular aggregates and form a very efficient network for excitonic energy migration. Here, we present a theoretical study of excitation energy transfer (EET) in the chlorosome based on experimental evidence of the molecular assembly. Our model for the exciton dynamics throughout the antenna combines a stochastic time propagation of the excitonic wave function with molecular dynamics simulations of supramolecular structure, and electronic structure calculations of the excited states. The simulation results reveal a detailed picture of the EET in the chlorosome. Coherent energy transfer is significant only for the first 50 fs after the initial excitation, and the wavelike motion of the exciton is completely damped at 100 fs. Characteristic time constants of incoherent energy transfer, subsequently, vary from 1 ps to se...

  3. Green Synthesis and Characterization of Silver Nanoparticles for Antimicrobial Activity Against Burn Wounds Contaminating Bacteria

    Science.gov (United States)

    Rout, Anandini; Jena, Padan K.; Sahoo, Debasish; Parida, Umesh K.; Bindhani, Birendra K.

    2014-04-01

    Silver nanoparticles (AgNPs) were prepared from the plant extract of N. arbor-tristis under atmospheric conditions through green synthesis and characterized by various physicochemical techniques like UV-Visible spectroscopy, IR Spectra, energy dispersive X-ray spectrometry (EDS), X-ray diffraction and transmission electron microscopy (TEM) and the results confirmed the synthesis of homogeneous and stable AgNPs by the plant extracts. The antimicrobial activity of AgNPs was investigated against most common bacteria found in burn wound Staphylococcus epidermidis and Pseudomonas aeruginosa. In these tests, Mueller Hinton agar plates were used with AgNPs of various concentrations, supplemented in liquid systems. P. aeruginosa was inhibited at the low concentration of AgNPs, whereas the growth-inhibitory effect on S. epidermidis was mild. These results suggest that AgNPs can be used as effective growth inhibitors of various microorganisms, making them applicable to diverse medical devices and antimicrobial control systems.

  4. Selection of oleuropein-degrading lactic acid bacteria strains isolated from fermenting Moroccan green olives

    Directory of Open Access Journals (Sweden)

    Ghabbour, N.

    2011-03-01

    Full Text Available A total of 177 strains of lactic acid bacteria (LAB were isolated from early-stage Moroccan Picholine green olive fermentation, including Lactobacillus plantarum (44.63%, Lactobacillus pentosus (25.99%, Lactobacillus brevis (9.61% and Pediococcus pentosaceus (19.77%. All the isolates were screened for their tolerance to olive leaf extract and oleuropein. Most of the isolates (85.3% were found able to degrade oleuropein, when evaluated by either oleuropein or 5-Bromo- 4-chloro-3-indolyl ?-D-glucuronide (X-Gluc as substrates. The biodegradation capacity of the selected strains of each species was confirmed by HPLC analysis.

    Un total de 177 cepas de bacterias ácido lácticas (LAB fueron aisladas en las primeras etapas de la fermentación de aceitunas verdes marroquíes Picholine, incluyendo Lactobacillus plantarum (44.63%, Lactobacillus pentosus (25.99%, Lactobacillus brevis (9.61% y Pediococcus pentosaceus (19.77%. Todos los aislados fueron evaluados mediante su tolerancia a extractos de hojas de olivo y oleuropeína. La mayoría de los aislados (85,3% degradaron oleuropeína, cuando fueron evaluados usando oleuropeína o 5-Bromo-4-cloro- 3-indolil ?-D-glucuronido (X-Gluc como sustrato. La capacidad de biodegradación de las cepas seleccionadas para cada especie fue confirmada mediante análisis por HPLC.

  5. Natural polysulfides- reactive sulfur species from Allium with applications in medicine and agriculture

    OpenAIRE

    Anwar, Awais

    2009-01-01

    Natural sulfur compounds from plants, bacteria, fungi and animals frequently exhibit interesting biological activities, such as antioxidant, antimicrobial and anticancer activity. Considering the recent developments in medicine (e.g. oxidative stress in ageing, antibiotic resistant bacteria, and selective anticancer agents) and Agriculture (e.g. 'green'; pesticides), several of these compounds have become the focus of interdisciplinary research. Among the various sulfur agents isolated to dat...

  6. Circular dichroism measured on single chlorosomal light-harvesting complexes of green photosynthetic bacteria

    KAUST Repository

    Furumaki, Shu

    2012-12-06

    We report results on circular dichroism (CD) measured on single immobilized chlorosomes of a triple mutant of green sulfur bacterium Chlorobaculum tepidum. The CD signal is measured by monitoring chlorosomal bacteriochlorphyll c fluorescence excited by alternate left and right circularly polarized laser light with a fixed wavelength of 733 nm. The excitation wavelength is close to a maximum of the negative CD signal of a bulk solution of the same chlorosomes. The average CD dissymmetry parameter obtained from an ensemble of individual chlorosomes was gs = -0.025, with an intrinsic standard deviation (due to variations between individual chlorosomes) of 0.006. The dissymmetry value is about 2.5 times larger than that obtained at the same wavelength in the bulk solution. The difference can be satisfactorily explained by taking into account the orientation factor in the single-chlorosome experiments. The observed distribution of the dissymmetry parameter reflects the well-ordered nature of the mutant chlorosomes. © 2012 American Chemical Society.

  7. Screening of antagonistic bacteria against the green mold disease (Trichoderma harzianum Rifai of Grey Oyster Mushroom (Pleurotus pulmonarius (Fr. Quel.

    Directory of Open Access Journals (Sweden)

    Nualsri, C.

    2005-01-01

    Full Text Available A total of 174 strains of bacteria antagonistic against the green mold (Trichoderma harzianum, isolated from cultivating bags and fruiting bodies of the mushrooms, were screened for effects on mushroom mycelia and ability to control the green mold disease. Twenty-eight of them promoted the primodia formation of the Pleurotus pulmonarius mycelia on agar plates. Twenty-two isolates were selected and further tested in a mushroom house. Cell suspension of each isolate was prepared and sprayed onto the spawn surface of P. pulmonarius. Fifteen isolates shortened the times required from watering to 2nd and 3rd flushing and increased yield of the basidiocarps by 1.1-34.3% over 30 days. Six isolates of bacteria which showed an inhibitory effect against T. harzianum, enhanced primordia formation and increased yield of P. pulmonarius were selected and used for control testing in a cultivation house. The suspension of each isolate was sprayed onto the spawn surface immediately after exposure to the air in the mushroom house, followed by spore suspension of T. harzianum two days later. The number of infected bags was counted at 30 days after inoculation and the cumulative yield was compared after 60 days. The results showed that bacteria isolate B012-022 was highly effective in suppressing the green mold disease.Only 6.7% of the cultivating bags were found to be infected by T. harzianum when bacteria isolate B012-022 was applied. Cumulative yield obtained from 900 g of 94% sawdust + 5% rice bran + 1% Ca(OH2 was 300.0 g/bag after 60 days, 71.1% higher than the bags infected by the green mold and without bacterial spraying. Identification of the six bacterial isolates showed all to be Bacillus spp.

  8. Menaquinone-7 in the reaction center complex of the green sulfur bacterium Chlorobium vibrioforme functions as the electron acceptor A1

    DEFF Research Database (Denmark)

    Kjaer, B; Frigaard, N-U; Yang, F; Zybailov, B; Miller, M; Golbeck, J H; Scheller, H V

    1998-01-01

    Photosynthetically active reaction center complexes were prepared from the green sulfur bacterium Chlorobium vibrioforme NCIMB 8327, and the content of quinones was determined by extraction and high-performance liquid chromatography. The analysis showed a stoichiometry of 1.7 molecules of menaquinone-7/reaction center. No other quinones were detected in the isolated reaction centers, whereas membrane preparations also contained chlorobiumquinone. The possible involvement of quinones in electron ...

  9. Retrieved bacteria from Noctiluca miliaris (green) bloom of the northeastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Basu, S.; Matondkar, S.G.P.; Furtado, I.

    cohnii, Bacillus flexus, and Bacillus cereus. The approx. 2-3 fold higher plate counts of culturable bacteria from the open-waters of the NAS indicate that these bacteria could critically determine the biogeochemical dynamics of the bloom and its milieu...

  10. Preliminary investigations of hydrogen peroxide treatment of selected ornamental fishes and efficacy against external bacteria and parasites in green swordtails.

    Science.gov (United States)

    Russo, Riccardo; Curtis, Eric W; Yanong, Roy P E

    2007-06-01

    The objectives of these preliminary studies were to evaluate the use of hydrogen peroxide (H2O2) for the treatment of selected species of ornamental fishes and its efficacy in treating external bacteria and parasites. In the first part of the study, fish of five species (serpae tetra Hyphessobrycon eques (also known as Serpa tetra H. serpae), tiger barb Puntius tetrazona, blue gourami Trichogaster trichopterus, suckermouth catfish Hypostomus plecostomus, and green swordtail Xiphophorus hellerii) were exposed to H2O2 for 1 h at concentrations between 6 and 34 mg/L or for 24 h at concentrations between 1 and 6 mg/L. The results were species specific: green swordtails tolerated all of the treatments, serpae tetras and tiger barbs were sensitive only to the highest concentration, and mortalities of suckermouth catfish and blue gourami were recorded in every treatment. In the second part of the study, clinically healthy green swordtails and fish infested with external motile rod-shaped bacteria (i.e., Ichthyobodo spp., Trichodina spp., and Gyrodactylus spp.) were treated with several concentrations of H2O2. A single H2O2 treatment of 3.1 mg/L or more for 1 h effectively eliminated external bacteria, concentrations of 6.5 mg/L or more appeared to effectively kill Ichthyobodo spp., and none of the treatments tested was effective against Trichodina spp. or Gyrodactylus spp. These preliminary findings suggest that H2O2 is effective for treating certain external bacterial infections and flagellate infestations in some species of ornamental fish at the dosages tested. Other treatment regimens may need to be tested for effectiveness against Trichodina spp. and Dactylogyrus spp. PMID:18201053

  11. Augmentation of potential phosphate solubilizing bacteria (PSB stimulate growth of green mustard (Brasica caventis Oed. in marginal soil

    Directory of Open Access Journals (Sweden)

    SULIASIH

    2006-01-01

    Full Text Available The potential of phosphate solubilizing bacteria/PSB (Bacillus megaterium, B. pantothenticus, Chromobacterium lividum and Klebsiella aerogenes were used as biofertilizer to increase the fresh leaf production of green mustard (Brasica caventis Oed.. An experiment was conducted at green house condition. The experiment were used 18 treatments such as single isolate of potential PSB (A,B,C,D, inoculants contain two isolates of potential PSB (E,F,G,H,I,J, inoculants contain three isolates of potential PSB (K, L, M, N, inoculants contain four isolate of potential PSB (O, chemistry fertilizer (P = control 1, organic fertilizer (Q = control 2, and without fertilizer (R = control 3. The treatments were arranged in Completely Randomized Design (CRD with 5 replications. The result showed that the inoculants of potential PSB increased the fresh plant production of green mustard. The mix of four isolates of potential PSB (inoculants O was the best to increase the fresh plant production of green mustard until 32.87% than other PSB inoculants, 207.84% than control 1,217.23% than control 2, and 930.60% than control 3.

  12. Big bacteria

    DEFF Research Database (Denmark)

    Schulz, HN; Jørgensen, BB

    2001-01-01

    A small number of prokaryotic species have a unique physiology or ecology related to their development of unusually large size. The biomass of bacteria varies over more than 10 orders of magnitude, from the 0.2 mum wide nanobacteria to the largest cells of the colorless sulfur bacteria, Thiomargarita namibiensis, with a diameter of 750 mum. All bacteria, including those that swim around in the environment, obtain their food molecules by molecular diffusion. Only the fastest and largest swimmers ...

  13. New Unstable Variants of Green Fluorescent Protein for Studies of Transient Gene Expression in Bacteria

    OpenAIRE

    Andersen, Jens Bo; Sternberg, Claus; Poulsen, Lars Kongsbak; Bjørn, Sara Petersen; Givskov, Michael; Molin, Søren

    1998-01-01

    Use of the green fluorescent protein (Gfp) from the jellyfish Aequorea victoria is a powerful method for nondestructive in situ monitoring, since expression of green fluorescence does not require any substrate addition. To expand the use of Gfp as a reporter protein, new variants have been constructed by the addition of short peptide sequences to the C-terminal end of intact Gfp. This rendered the Gfp susceptible to the action of indigenous housekeeping proteases, resulting in protein variant...

  14. Utility of Green Fluorescent Nucleic Acid Dyes and Aluminum Oxide Membrane Filters for Rapid Epifluorescence Enumeration of Soil and Sediment Bacteria

    OpenAIRE

    Weinbauer, Markus G.; Beckmann, Christiane; Höfle, Manfred G.

    1998-01-01

    High background fluorescence and unspecific staining hampered the epifluorescence enumeration of bacteria in 45% of the tested soil and sediment samples with 4?,6-diamidino-2-phenylindole (DAPI) and polycarbonate membrane filters. These problems of the determination of total cell counts can be circumvented by using green fluorescent high-affinity nucleic acid dyes and aluminum oxide membrane filters. Due to the bright staining of cells, we recommend SYBR Green II as dye.

  15. Characterizing mechanisms of extracellular electron transport in sulfur and iron-oxidizing electrochemically active bacteria isolated from marine sediments

    Science.gov (United States)

    Rowe, A. R.; Bird, L. J.; Lam, B. R.; Nealson, K. H.

    2014-12-01

    Lithotrophic reactions, including the oxidation of mineral species, are often difficult to detect in environmental systems. This could be due to the nature of substrate or metabolite quantification or the rapid consumption of metabolic end products or intermediates by proximate biological or abiotic processes. Though recently genetic markers have been applied to detecting these processes in environmental systems, our knowledge of lithotrophic markers are limited to those processes catalyzed by organisms that have been cultured and physiologically characterized. Here we describe the use of electrochemical enrichment techniques to isolate marine sediment-dwelling microbes capable of the oxidation or insoluble forms of iron and sulfur including both the elemental species. All the organisms isolated fall within the Alphaproteobacteria and Gammaproteobacteria and are capable of acquiring electrons from an electrode while using either oxygen or nitrate as a terminal electron acceptor. Electrochemical analysis of these microbes has demonstrated that, though they have similar geochemical abilities (either sulfur or iron oxidation), they likely utilize different biochemical mechanisms demonstrated by the variability in dominant electron transfer modes or interactions (i.e., biofilm, planktonic or mediator facilitated interactions) and the wide range of midpoint potentials observed for dominant redox active cellular components (ranging from -293 to +50 mV vs. Ag/AgCl). For example, organisms isolated on elemental sulfur tended to have higher midpoint potentials than iron-oxidizing microbes. A variety of techniques are currently being applied to understanding the different mechanisms of extracellular electron transport for oxidizing an electrode or corresponding insoluble electron donor including both genomic and genetic manipulation experiments. The insight gained from these experiments is not limited to the physiology of the organisms isolated but will also aid in identification of genetic targets to better understand the ecologic importance of lithotrophs and the role solid substrates may play in their metabolism.

  16. Isolation and phylogenetic characterization of iron-sulfur-oxidizing heterotrophic bacteria indigenous to nickel laterite ores of Sulawesi, Indonesia: Implications for biohydrometallurgy

    Science.gov (United States)

    Chaerun, Siti Khodijah; Hung, Sutina; Mubarok, Mohammad Zaki; Sanwani, Edy

    2015-09-01

    The main objective of this study was to isolate and phylogenetically identify the indigenous iron-sulfur-oxidizing heterotrophic bacteria capable of bioleaching nickel from laterite mineral ores. The bacteria were isolated from a nickel laterite mine area in South Sulawesi Province, Indonesia. Seven bacterial strains were successfully isolated from laterite mineral ores (strains SKC/S-1 to SKC/S-7) and they were capable of bioleaching of nickel from saprolite and limonite ores. Using EzTaxon-e database, the 16S rRNA gene sequences of the seven bacterial strains were subjected to phylogenetic analysis, resulting in a complete hierarchical classification system, and they were identified as Pseudomonas taiwanensis BCRC 17751 (98.59% similarity), Bacillus subtilis subsp. inaquosorum BGSC 3A28 (99.14% and 99.32% similarities), Paenibacillus pasadenensis SAFN-007 (98.95% and 99.33% similarities), Bacillus methylotrophicus CBMB 205 (99.37% similarity), and Bacillus altitudinis 41KF2b (99.37% similarity). It is noteworthy that members of the phylum Firmicutes (in particular the genus Bacillus) predominated in this study, therefore making them to have the high potential to be candidates for the bioleaching of nickel from laterite mineral ores. To our knowledge, this is the first report on the predominance of the phylum Firmicutes in the Sulawesi laterite mineral ores.

  17. Bioenergetic studies of coal sulfur oxidation by extremely thermophilic bacteria. Final report, September 15, 1992--August 31, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, R.M.; Han, C.J.

    1997-12-31

    Thermoacidophilic microorganisms have been considered for inorganic sulfur removal from coal because of expected improvements in rates of both biotic and abiotic sulfur oxidation reactions with increasing temperature. In this study, the bioenergetic response of the extremely thermoacidophilic archaeon, Metallosphaera sedula, to environmental changes have been examined in relation to its capacity to catalyze pyrite oxidation in coal. Given an appropriate bioenergetic challenge, the metabolic response was to utilize additional amounts of energy sources (i.e., pyrite) to survive. Of particular interest were the consequences of exposing the organism to various forms of stress (chemical, nutritional, thermal, pH) in the presence of coal pyrite. Several approaches to take advantage of stress response to accelerate pyrite oxidation by this organism were examined, including attempts to promote acquired thermal tolerance to extend its functional range, exposure to chemical uncouplers and decouplers, and manipulation of heterotrophic and chemolithotrophic tendencies to optimize biomass concentration and biocatalytic activity. Promising strategies were investigated in a continuous culture system. This study identified environmental conditions that promote better coupling of biotic and abiotic oxidation reactions to improve biosulfurization rates of thermoacidophilic microorganisms.

  18. Formation of Fe(III)-containing mackinawite from hydroxysulphate green rust by sulphate reducing bacteria

    International Nuclear Information System (INIS)

    The interactions between Fe(II-III) hydroxysulphate GR(SO42-) and sulphate reducing bacteria (SRB) were studied. The considered SRB, Desulfovibrio desulfuricans subsp. aestuarii ATCC 29578, were added with GR(SO42-) to culture media. Different conditions were envisioned, corresponding to various concentrations of bacteria, various sources of sulphate (dissolved SO42- + GR(SO42-) or GR(SO42-) alone) and various atmospheres (N2:H2 or N2:CO2:H2). In the first part of the study, CO2 was deliberately omitted so as to avoid the formation of carbonated compounds, and GR(SO42-) was the only source of sulphate. Cell concentration increases from ?4 x 107 to ?7 x 108 cells/mL in 2 weeks. The evolution with time of the iron compounds, monitored by Raman spectroscopy and X-ray diffraction, showed the progressive formation of a FeS compound, the Fe(III)-containing mackinawite. This result is consistent with the association GR(SO42-)/SRB/FeS observed in rust layers formed on steel in seawater. In the presence of CO2 and additional dissolved sulphate species, a rapid growth of the bacteria could be observed, leading to the total transformation of GR(SO42-) into mackinawite, found in three physico-chemical states (nanocrystalline, crystalline stoichiometric FeS and Fe(III)-containing), and siderite FeCO3.

  19. New unstable variants of green fluorescent protein for studies of transient gene expression in bacteria

    DEFF Research Database (Denmark)

    Andersen, Jens Bo; Sternberg, Claus

    1998-01-01

    Use of the green fluorescent protein (Gfp) from the jellyfish Aequorea victoria ia is a powerful method for nondestructive in situ monitoring, since expression of green fluorescence does not require any substrate addition. To expand the use of Gfp as a reporter protein, new variants have been constructed by the addition of short peptide sequences to the C-terminal end of intact Gfp. This rendered the Gfp susceptible to the action of indigenous housekeeping proteases, resulting in protein variants with half-lives ranging from 40 min to a few hours when synthesized in Escherichia coli and Pseudomonas putida. The new Gfp variants should be useful for in situ studies of temporal gene expression.

  20. Use of green fluorescent protein to monitor survival of genetically engineered bacteria in aquatic environments.

    OpenAIRE

    Leff, L G; Leff, A A

    1996-01-01

    Many methods for detecting model genetically engineered microorganisms (GEMs) in experimental ecosystems rely on cultivation of introduced cells. In this study, survival of Escherichia coli was monitored with the green fluorescent protein (GFP) gene. This approach allowed enumeration of GEMs by both plating and microscopy. Use of the GFP-marked GEMs revealed that E. coli persisted in stream water at higher densities as determined microscopically than as determined by CFU enumeration. The GFP ...

  1. Exploring bacteria-induced growth and morphogenesis in the green macroalga order Ulvales (Chlorophyta)

    OpenAIRE

    Wichard, Thomas

    2015-01-01

    Green macroalgae, such as Ulvales, lose their typical morphology completely when grown under axenic conditions or in the absence of the appropriate microbiome. As a result, slow growing aberrant phenotypes or even callus-like morphotypes are observed in Ulvales. The cross-kingdom interactions between marine algae and microorganisms are hence not only restricted by the exchange of macronutrients, including vitamins and nutrients, but also by infochemicals such as bacterial morphogenetic compou...

  2. New aromatic biomarkers in sulfur-rich coal

    Energy Technology Data Exchange (ETDEWEB)

    Gorchs, R.; Olivella, M.A.; Heras, F.X.C. de las [Escola Universitaria Politecnica de Manresa, Catalonia (Spain)

    2003-12-01

    A molecular study of linear, branched and isoprenyl alkylbenzene skeletons and alkenylbenzenes in the soluble fraction extracted from a sulfur-rich Utrillas coal was carried out using gas chromatography-mass spectrometry (GC-MS). The presence of C{sub 24}-C{sub 28} diaromatic compounds, not previously reported in coals, suggests that photosynthetic green sulfur bacteria may have made an input of organic matter to these coals. The unsaturated linear alkenylbenzenes and isoprenyl (C{sub 15} and C{sub 20}) alkylbenzene skeletons are also described for the first time in the soluble fraction of geological samples. (author)

  3. Determination of antibacterial activity of green coffee bean extract on periodontogenic bacteria like Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans: An in vitro study

    Science.gov (United States)

    Bharath, Nagaraj; Sowmya, Nagur Karibasappa; Mehta, Dhoom Singh

    2015-01-01

    Background: The aim of this study was to evaluate the antibacterial activity of pure green coffee bean extract on periodonto pathogenic bacteria Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Fusobacterium nucleatum (Fn) and Aggregatibacter actinomycetemcomitans (Aa). Materials and Methods: Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBC) were used to assess the antibacterial effect of pure green coffee bean extract against periodonto pathogenic bacteria by micro dilution method and culture method, respectively. Results: MIC values of Pg, Pi and Aa were 0.2 ?g/ml whereas Fn showed sensitive at concentration of 3.125 ?g/ml. MBC values mirrors the values same as that of MIC. Conclusion: Antimicrobial activity of pure green coffee bean extract against Pg, Pi, Fn and Aa suggests that it could be recommended as an adjunct to mechanical therapy in the management of periodontal disease. PMID:26097349

  4. Antioxidant efficacy of crude methanol extract of ashitaba green tea against radiation induced oxidative stress in E.coli K12 bacteria

    International Nuclear Information System (INIS)

    This study was undertaken to evaluate the antioxidant activity of methanol crude extract of ashitaba green tea (G). The DPPH scavenging assay was evaluated for green tea extract to determine its radical scavenging capacity. The bacteria was pretreated with ashitaba green tea extract, quercetin (Q) and (-) epigallocatechin -3-gallate (E) at below MIC level. Oxidative stress was induced at 0.4 Gy using gamma radiation. The antioxidant efficacy of ashitaba green tea was evaluated through enzyme antioxidant studies like SOD (Superoxidedismutase) and CAT (Catalase). The oxidative stress marker Thiobarbituric acid-reactive substance (TBARS) was also evaluated. Further the protective efficacy of the(G) was confirmed by colony forming units (CFU) study. Among the tested compounds the crude extract of ashitaba (G) exhibited excellent antioxidant activity in comparison with quercetin and (-) epigallocatechin -3-gallate. (abstract)

  5. "Green preservatives": combating fungi in the food and feed industry by applying antifungal lactic acid bacteria.

    Science.gov (United States)

    Pawlowska, Agata M; Zannini, Emanuele; Coffey, Aidan; Arendt, Elke K

    2012-01-01

    Fungal food spoilage plays a pivotal role in the deterioration of food and feed systems and some of them are also able to produce toxic compounds for humans and animals. The mycotoxins produced by fungi can cause serious health hazards, including cancerogenic, immunotoxic, teratogenic, neurotoxic, nephrotoxic and hepatotoxic effects, and Kashin-Beck disease. In addition to this, fungal spoilage/pathogens are causing losses of marketable quality and hygiene of foodstuffs, resulting in major economic problem throughout the world. Nowadays, food spoilage can be prevented using physical and chemical methods, but no efficient strategy has been proposed so far to reduce the microbial growth ensuring public health. Therefore, lactic acid bacteria (LAB) can play an important role as natural preservatives. The protection of food products using LAB is mainly due to the production of antifungal compounds such as carboxylic acids, fatty acids, ethanol, carbon dioxide, hydrogen peroxide, and bacteriocins. In addition to this, LAB can also positively contribute to the flavor, texture, and nutritional value of food products. This review mainly focuses on the use of LAB for food preservation given their extensive industrial application in a wide range of foods and feeds. The attention points out the several industrial patents concerning the use of antifungal LAB as biocontrol agent against spoilage organisms in different fermented foods and feeds. PMID:22909981

  6. One-pot green synthesis of carbon dots by using Saccharum officinarum juice for fluorescent imaging of bacteria (Escherichia coli) and yeast (Saccharomyces cerevisiae) cells

    Energy Technology Data Exchange (ETDEWEB)

    Mehta, Vaibhavkumar N. [Applied Chemistry Department, S. V. National Institute of Technology, Surat, 395 007 (India); Jha, Sanjay [Gujarat Agricultural Biotechnology Institute, Navsari Agricultural University, Surat, 395007 (India); Kailasa, Suresh Kumar, E-mail: sureshkumarchem@gmail.com [Applied Chemistry Department, S. V. National Institute of Technology, Surat, 395 007 (India)

    2014-05-01

    We are reporting highly economical plant-based hydrothermal method for one-pot green synthesis of water-dispersible fluorescent carbon dots (CDs) by using Saccharum officinarum juice as precursor. The synthesized CDs were characterized by UV-visible, fluorescence, Fourier transform infrared (FT-IR), dynamic light scattering (DLS), high-resolution transmission electron microscopic (HR-TEM), and laser scanning confocal microscopic techniques. The CDs are well dispersed in water with an average size of ? 3 nm and showed bright blue fluorescence under UV-light (?{sub ex} = 365 nm). These CDs acted as excellent fluorescent probes in cellular imaging of bacteria (Escherichia coli) and yeast (Saccharomyces cerevisiae). - Highlights: • One-pot green synthesis was used for fluorescent CDs. • FT-IR, DLS, and TEM were used for the characterization of CDs. • The CDs are well dispersed in water with an average size of ? 3 nm. • The CDs acted as fluorescent probes for imaging of bacteria and yeast cells.

  7. AKTIVITAS ANTIBAKTERI FRAKSI-FRAKSI EKSTRAK SIRIH HIJAU (Piper betle Linn TERHADAP PATOGEN PANGAN [Antibacterial Activity of Fractionated Green Sirih (Piper betle Linn Extract Against Food Pathogenic Bacteria

    Directory of Open Access Journals (Sweden)

    Maggy T. Suhartono

    2012-12-01

    Full Text Available Fractionation of green sirih (Piper betle Linn extract by chromatography colom using the mixture of several solvents i.e. chloroform, ethanol and acetic acid (4:1:1 resulted in 17 fractions. All fractions showed antibacterial activities but only 2 fractions (fraction 3 and fraction 4 showed the highest inhibition towards the six tested bacteria Escherichia coli, Salmonella Typhimurium, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus and Listeria monocytogenes. Among the tested bacteria, all fractions of green sirih extracts showed the most effective inhibition against, Salmonella Typhimurium with inhibition zone diameters ranging from 10 mm to 26 mm. Identification using GC-MS found that fraction 3 and fraction 4 contained chavicol; dodecanoic acid, myristic, palmitic and oleic acid.

  8. One-pot green synthesis of carbon dots by using Saccharum officinarum juice for fluorescent imaging of bacteria (Escherichia coli) and yeast (Saccharomyces cerevisiae) cells

    International Nuclear Information System (INIS)

    We are reporting highly economical plant-based hydrothermal method for one-pot green synthesis of water-dispersible fluorescent carbon dots (CDs) by using Saccharum officinarum juice as precursor. The synthesized CDs were characterized by UV-visible, fluorescence, Fourier transform infrared (FT-IR), dynamic light scattering (DLS), high-resolution transmission electron microscopic (HR-TEM), and laser scanning confocal microscopic techniques. The CDs are well dispersed in water with an average size of ? 3 nm and showed bright blue fluorescence under UV-light (?ex = 365 nm). These CDs acted as excellent fluorescent probes in cellular imaging of bacteria (Escherichia coli) and yeast (Saccharomyces cerevisiae). - Highlights: • One-pot green synthesis was used for fluorescent CDs. • FT-IR, DLS, and TEM were used for the characterization of CDs. • The CDs are well dispersed in water with an average size of ? 3 nm. • The CDs acted as fluorescent probes for imaging of bacteria and yeast cells

  9. Developing a Biofilm of Sulfur Oxidizing Bacteria, Starting-up and Operating a Bioscrubber Treating H2S

    Directory of Open Access Journals (Sweden)

    Gholamreza Moussavi

    2007-01-01

    Full Text Available Development of an acclimatized SOB biofilm, startup and performance of a fixed bed bioscrubber packed with corrugated tube parts as a media having high specific surface area was investigated. Bioscrubber was a cylindrical Plexiglas air-and water-tight column with 10 L in working bed volume. Sludge from a tannery wastewater treatment plant was used as a seed for SOB separation, acclimation and enrichment. Enriched acclimatized SOB were applied as inoculum for biofilm development, which was carried out by recirculating the prepared microbial suspension through the bed. Thickness of the developed biofilm was 56 ?m in which active acidophilic autotrophic H2S oxidizing bacteria were completely predominated. Activity measurements showed highest biodegradation rate of biofilm at liquid pH around 3. Due to employing an efficient specialized biofilm, startup period of the reactor was quite short and H2S removal efficiency just 12 h after starting up reached above of 92% and increased to 96% at day 3 of starting up while inlet H2S concentration gradually was increased to around 30 ppm. At the end of start up pH of the recycle liquid was modified to the optimal value of 3±0.5 in which biofilm demonstrated the highest activity in terms of OUR after which removal efficiency increased around 3% while other operating conditions were consistent. Furthermore, performance of the bioscrubber was evaluated at various inlet H2S concentrations ranging from 30 to 150 ppmv. It was indicated that the inlet H2S concentrations in studied range did not affect the performance of the bioscrubber so that the removal efficiency of H2S was greater than 99.4% at all concentrations. These observations suggested that the development of an efficient specialized SOB biofilm on a media with high specific surface area will decrease the startup course and achieve high removal efficiency in the bioscrubber treating H2S. In addition, operation in acidic recycle liquid will overcome use of alkaline to adjust the pH, which reduce the operation cost of the control system.

  10. Green Fluorescent Protein-Labeled Monitoring Tool To Quantify Conjugative Plasmid Transfer between Gram-Positive and Gram-Negative Bacteria

    OpenAIRE

    Arends, Karsten; Schiwon, Katarzyna; Sakinc, Türkan; Hübner, Johannes; Grohmann, Elisabeth

    2012-01-01

    On the basis of pIP501, a green fluorescent protein (GFP)-tagged monitoring tool was constructed for quantifying plasmid mobilization among Gram-positive bacteria and between Gram-positive Enterococcus faecalis and Gram-negative Escherichia coli. Furthermore, retromobilization of the GFP-tagged monitoring tool was shown from E. faecalis OG1X into the clinical isolate E. faecalis T9.

  11. Synthesis of self-aggregative zinc chlorophylls possessing polymerizable esters as a atable model compound for main light-harvesting antennas of green photosynthetic bacteria

    OpenAIRE

    Reiko Shibata; Kazuya Nishihara; Hitoshi Tamiaki

    2006-01-01

    Zinc bacteriochlorophyll-d derivatives possessing a polymerizable moiety at the 17-propionate were prepared as model compounds of natural occurring chlorophylls in the main peripheral antennas of green photosynthetic bacteria (chlorosomes). The synthetic compounds self-aggregated in nonpolar organic solvents as well as in the solid state to give large oligomers similar to chlorosomal J-aggregates. Such introduction of the polymerizable groups in the ester did not suppress the ability of ...

  12. Big bacteria

    DEFF Research Database (Denmark)

    Schulz, HN; JØrgensen, BB

    2001-01-01

    A small number of prokaryotic species have a unique physiology or ecology related to their development of unusually large size. The biomass of bacteria varies over more than 10 orders of magnitude, from the 0.2 mum wide nanobacteria to the largest cells of the colorless sulfur bacteria, Thiomargarita namibiensis, with a diameter of 750 mum. All bacteria, including those that swim around in the environment, obtain their food molecules by molecular diffusion. Only the fastest and largest swimmers known, Thiovulum majus, are able to significantly increase their food supply by motility and by actively creating an advective flow through the entire population. Diffusion limitation generally restricts the maximal size of prokaryotic cells and provides a selective advantage for mum-sized cells at the normally low substrate concentrations in the environment. The largest heterotrophic bacteria, the 80 x 600 mum large Epulopiscium sp. from the gut of tropical fish, are presumably living in a very nutrient-rich medium. Many large bacteria contain numerous inclusions in the cells that reduce the volume of active cytoplasm. The most striking examples of competitive advantage from large cell size are found among the colorless sulfur bacteria that oxidize hydrogen sulfide to sulfate with oxygen or nitrate. The several-cm-long filamentous species can penetrate up through the ca 500-mum-thick diffusive boundary layer and may thereby reach into water containing their electron acceptor, oxygen or nitrate. By their ability to store vast quantities of both nitrate and elemental sulfur in the cells, these bacteria have become independent of the coexistence of their substrates. In fact, a close relative, T. namibiensis, can probably respire in the sulfidic mud for several months before again filling up their large vacuoles with nitrate.

  13. A Green and Highly Efficient Solvent-free Synthesis of Novel Calicx[4]resorcinarene Derivatives Using Tungstate Sulfuric Acid

    International Nuclear Information System (INIS)

    A facile and simple procedure for the synthesis of novel and known calix[4]resorcinarene derivatives were developed via a reaction of arylaldehydes with resorcinol in the presence of catalytic amounts of tungstate sulfuric acid (TSA) under solvent-free conditions. This eco-friendly method has many appealing attributes, such as excellent yields, short reactions times, use of safe and recoverable catalyst, and simple work-up procedures. TSA was characterized by powdered X-ray diffraction (XRD), X-ray fluorescence (XRF) and FTIR spectroscopy

  14. Skin Bacteria Diversity and Spatial Distribution in Litoria genimaculata (GREEN- EYED TREE FROG Body Parts and its Bd-Inhibitory Activity -abstract-

    Directory of Open Access Journals (Sweden)

    Martha L Silva-Velasco

    2014-12-01

    Full Text Available Several amphibian skin bacteria have shown inhibitory activity against the pathogenic fungus Batrachochytrium dendrobatidis (Bd. However‚ little is known about the spatial distribution of these inhibitory bacteria on amphibian skin‚ or their diversity. We looked at the diversity and distribution of skin bacteria of the green-eyed tree frog Litoria genimaculata. This stream-dwelling species from North Queensland rainforest declined in the early 1990s but has since recovered to pre-decline range population sizes. Swabs were taken from 5 body parts (hands‚ feet‚ legs and dorsal and ventral surfaces and inoculated onto agar plates for isolation of bacterial colonies. Bd- inhibitory activity was tested in challenge essays. Results show that feet had the highest number of bacterial isolates with Bd inhibitory activity followed by hands and legs with similar numbers of bacterial isolates and ventral body parts in that order. The dorsal surface had the lowest number of Bd inhibitory isolates. No sampled frogs were infected with Bd according to PCR assays‚ although Bd is endemic at the site. Information from morphological observations and Gram stains will be used to classify the bacterial isolates. Results will be analyzed for any patterns of distribution across the body of the frogs. Possible associations between body parts and bacterial isolates with and without Bd-inhibitory activity will be examined. This study will contribute to knowledge of the community structure of skin bacteria in frogs. Characterization of skin bacteria diversity is one of the first steps in understanding the role of amphibian skin bacteria in the resistance of the hosts to chytridiomycosis.

  15. Benevolent behavior of Kleinia grandiflora leaf extract as a green corrosion inhibitor for mild steel in sulfuric acid solution

    Science.gov (United States)

    Pitchaipillai, Muthukrishnan; Raj, Karthik; Balasubramanian, Jeyaprabha; Periakaruppan, Prakash

    2014-11-01

    The ethanolic extract of Kleinia grandiflora leaves was characterized and tested for its potential anticorrosion properties on mild steel in 1 M H2SO4 medium using mass-loss analysis, potentiodynamic polarization measurements, electrochemical impedance spectroscopy, Fourier-transform infrared spectroscopy, scanning electron microscopy, UV-visible spectroscopy, and X-ray diffraction analysis. The effect of temperature on the corrosion behavior of mild steel was studied in the range of 308 to 328 K. The inhibition efficiency was observed to increase with increasing concentration of the extract. Polarization curves revealed that the Kleinia grandiflora leaf extract is a mixed inhibitor. Impedance diagrams revealed that an increase of Kleinia grandiflora leaf extract concentration increased the charge transfer resistance and decreased the double-layer capacitance. The adsorption process obeys Langmuir's model, with a standard free energy of adsorption (? G ads) of -18.62 kJ/mol. The obtained results indicate that the Kleinia grandiflora leaf extract can serve as an effective inhibitor for the corrosion of mild steel in a sulfuric acid medium.

  16. Reconstitution of an Active Magnesium Chelatase Enzyme Complex from the bchI, -D, and -H Gene Products of the Green Sulfur Bacterium Chlorobium vibrioforme Expressed in Escherichia coli

    OpenAIRE

    Petersen, Bent L.; Jensen, Poul Erik; Gibson, Lucien C D; Stummann, Bjarne M.; Hunter, C. Neil; Henningsen, Knud W.

    1998-01-01

    Magnesium-protoporphyrin chelatase, the first enzyme unique to the (bacterio)chlorophyll-specific branch of the porphyrin biosynthetic pathway, catalyzes the insertion of Mg2+ into protoporphyrin IX. Three genes, designated bchI, -D, and -H, from the strictly anaerobic and obligately phototrophic green sulfur bacterium Chlorobium vibrioforme show a significant level of homology to the magnesium chelatase-encoding genes bchI, -D, and -H and chlI, -D, and -H of Rhodobacter sphaeroides and Synec...

  17. Microbiological analysis of the population of extremely haloalkaliphilic sulfur-oxidizing bacteria dominating in lab-scale sulfide-removing bioreactors

    OpenAIRE

    Sorokin, D. Y.; Bosch, P.L.F., van den; Abbas, B.; Janssen, A. J. H.; Muyzer, G.

    2008-01-01

    Thiopaq biotechnology for partial sulfide oxidation to elemental sulfur is an efficient way to remove H2S from biogases. However, its application for high-pressure natural gas desulfurization needs upgrading. Particularly, an increase in alkalinity of the scrubbing liquid is required. Therefore, the feasibility of sulfide oxidation into elemental sulfur under oxygen limitation was tested at extremely haloalkaline conditions in lab-scale bioreactors using mix sediments from hypersaline soda la...

  18. Microbiological analysis of the population of extremely haloalkaliphilic sulfur-oxidizing bacteria dominating in lab-scale sulfide-removing bioreactors :

    OpenAIRE

    Sorokin, D. Y.; Van den Bosch, P.L.F.; Abbas, B.; Janssen, A. J. H.; Muyzer, G.

    2008-01-01

    Thiopaq biotechnology for partial sulfide oxidation to elemental sulfur is an efficient way to remove H2S from biogases. However, its application for high-pressure natural gas desulfurization needs upgrading. Particularly, an increase in alkalinity of the scrubbing liquid is required. Therefore, the feasibility of sulfide oxidation into elemental sulfur under oxygen limitation was tested at extremely haloalkaline conditions in lab-scale bioreactors using mix sediments from hypersaline soda la...

  19. Green synthesis of protein capped silver nanoparticles from phytopathogenic fungus Macrophomina phaseolina (Tassi) Goid with antimicrobial properties against multidrug-resistant bacteria

    Science.gov (United States)

    Chowdhury, Supriyo; Basu, Arpita; Kundu, Surekha

    2014-07-01

    In recent years, green synthesis of nanoparticles, i.e., synthesizing nanoparticles using biological sources like bacteria, algae, fungus, or plant extracts have attracted much attention due to its environment-friendly and economic aspects. The present study demonstrates an eco-friendly and low-cost method of biosynthesis of silver nanoparticles using cell-free filtrate of phytopathogenic fungus Macrophomina phaseolina. UV-visible spectrum showed a peak at 450 nm corresponding to the plasmon absorbance of silver nanoparticles. Scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM) revealed the presence of spherical silver nanoparticles of the size range 5 to 40 nm, most of these being 16 to 20 nm in diameter. X-ray diffraction (XRD) spectrum of the nanoparticles exhibited 2 ? values corresponding to silver nanoparticles. These nanoparticles were found to be naturally protein coated. SDS-PAGE analysis showed the presence of an 85-kDa protein band responsible for capping and stabilization of the silver nanoparticles. Antimicrobial activities of the silver nanoparticles against human as well as plant pathogenic multidrug-resistant bacteria were assayed. The particles showed inhibitory effect on the growth kinetics of human and plant bacteria. Furthermore, the genotoxic potential of the silver nanoparticles with increasing concentrations was evaluated by DNA fragmentation studies using plasmid DNA.

  20. Characterization of Sulfur Compounds in Coffee Beans by Sulfur K-XANES Spectroscopy

    International Nuclear Information System (INIS)

    In this 'feasibility study' the influence of roasting on the sulfur speciation in Mexican coffee beans was investigated by sulfur K-XANES Spectroscopy. Spectra of green and slightly roasted beans could be fitted to a linear combination of 'standard' reference spectra for biological samples, whereas longer roasting obviously involves formation of additional sulfur compounds in considerable amounts

  1. Safe use of genetically modified lactic acid bacteria in food: Bridging the gap between consumers, green groups, and industry

    Scientific Electronic Library Online (English)

    Wilbert, Sybesma; Jeroen, Hugenholtz; Willem M., de Vos; Eddy J., Smid.

    2006-07-15

    Full Text Available Within the European Union (EU), the use of genetically modified organisms (GMOs) in food production is not widely applied and accepted. In contrast to the United States of America, the current EU legislation limits the introduction of functional foods derived from GMOs that may bring a clear benefit [...] to the consumer. Genetically modified lactic acid bacteria (GM-LAB) can be considered as a different class of GMOs, and the European Union is preparing regulations for the risk assessment of genetically modified microorganisms. Since these procedures are not yet implemented, the current risk assessment procedure is shared for GMOs derived from micro organisms, plants, or animals. At present, the use of organisms in food production that have uncontrolled genetic alterations made through random mutagenesis, is permitted, while similar applications with organisms that have controlled genetic alterations are not allowed. The current paper reviews the opportunities that genetically modified lactic acid bacteria may offer the food industry and the consumer. An objective risk profile is described for the use of GM-LAB in food production. To enhance the introduction of functional foods with proven health claims it is proposed to adapt the current safety assessment procedures for (GM)-LAB and suggestions are made for the related cost accountability. A qualified presumption of safety as proposed by SANCO (EU SANCO 2003), based on taxonomy and on the history of safe use of LAB applied in food, could in the near future be applied to any kind of LAB or GM-LAB provided that a series of modern profiling methods are used to verify the absence of unintended effects of altered LAB that may cause harm to the health of the consumer.

  2. Green chemistry methods in sulfur dyeing: application of various reducing D-sugars and analysis of the importance of optimum redox potential.

    Science.gov (United States)

    Blackburn, Richard S; Harvey, Anna

    2004-07-15

    The importance of sulfur dyeing of cellulosic fibers, particularly cotton, is realized economically throughout the dyeing industry. At the present time, dyeing with sulfur dyes requires the use of various auxiliaries, many of which have adverse effects on the environment. The most damaging of these is the reducing agent sodium sulfide, required to reduce the dye molecules to a water-soluble leuco form to enable adsorption and diffusion into the fiber. In this study, attempts have been made to replace the sodium sulfide used within the sulfur dyeing process with a variety of environmentally friendly reducing sugars. The redox potential of various hexose and pentose monosaccharides and reducing disaccharides was recorded and compared. Subsequently, cotton was dyed with the world's most important sulfur dye, C. I. Sulfur Black 1, using the reducing sugars under alkaline conditions, and compared to dyeings secured by employing commercial sulfide reducing agents. It was observed that reducing sugars gave comparable, and in many cases superior, color strength and wash fastness results, with respect to the commercial sulfide-based reducing agents, which still account for the vast majority of sulfur dyeing processes and that pose significant environmental concern. Employment of reducing sugars in sulfur dyeing could provide a sustainable, nontoxic, biodegradable, cost-effective alternative to sodium polysulfide and sodium hydrogen sulfide. Comparison of the redox potential of reducing sugars against the color strength of the dyeings secured demonstrated that there was an optimum redox potential of around -650 mV for maximum color strength achieved. The same redox potential also conferred the lowest color loss upon washing. These observations were attributed to reduction of the polymeric dye molecules to an optimum size for fiber affinity and diffusion into the fiber, but which would also confer maximum wash fastness upon oxidation. PMID:15298216

  3. Effects of combined action of ?-irradiation and sulfur dioxide or N-methyl-N'-nitro-N-nitrosoguanidin on bacteria and higher plants

    International Nuclear Information System (INIS)

    Effect of combined action of of gamma-irradiation and sulfur dioxide or N-methyl-N-nitro-N-nitrosoguanidin on baceria (Bacillus subtilis) and higher plants (Hordeum vulgare L., Pinus sylvestris L.) have been studied. The number of barley germ root cells with chromosomal aberrations depends on the order of treatment with the studied agents. The coefficients of SO2 and gamma-irradiation correlation fluctuate from 1,3 to 2,6 in the above experiments. In experiments with pine seedlings, these correlation coefficients were similar to additive ones. The data obtained suggest that the pattern of action of the agents is determined by the radiation sensitivity of objects and the order of action of the agents

  4. Physico-Chemical and Microbial Quality of Locally Composted and Imported Green Waste Composts in Oman

    OpenAIRE

    SAIFELDIN A.F. EL-NAGERABI; ABDULKADIR E. ELSHAFIE; Al-Bahry, Saif N.; Hasina S. AlRawahi; Huda AlBurashdi

    2011-01-01

    In this work the physical, chemical and microbial properties of four locally composted green waste composts (GWCs) namely Almukhasib, Growers, Plantex, and Super along with four imported GWC (Florabella, Mikskaar, Potgrond, and Shamrock) were studied to evaluate the quality of these composts with the acceptable standards. All composts showed normal physical properties, except the bad smell from sulfur reducing bacteria in Almukhasib, light brown color Plantex and one viable weed seed in Shamr...

  5. Growth of Thiobacillus ferrooxidans on Elemental Sulfur

    OpenAIRE

    Espejo, Romilio T.; Romero, Pedro

    1987-01-01

    Growth kinetics of Thiobacillus ferrooxidans in batch cultures, containing prills of elementary sulfur as the sole energy source, were studied by measuring the incorporation of radioactive phosphorus in free and adsorbed bacteria. The data obtained indicate an initial exponential growth of the attached bacteria until saturation of the susceptible surface was reached, followed by a linear release of free bacteria due to successive replication of a constant number of adsorbed bacteria. These ad...

  6. Microbiological study of naturally fermented Algerian green olives: isolation and identification of lactic acid bacteria and yeasts along with the effects of brine solutions obtained at the end of olive fermentation on Lactobacillus plantarum...

    Directory of Open Access Journals (Sweden)

    Nour-Eddine, Karam

    2006-09-01

    Full Text Available The microflora of naturally fermented green olives produced in Western Algeria was studied over 15, 60 and 90 day fermentation periods. Different microorganisms (aerobic bacteria, coliforms, staphylococci, lactic acid bacteria, lactobacilli, enterococci, yeasts, psychrotrophs and lipolytic bacteria were recorded at 15 and 60 days of fermentation. After 90 days (pH 4.40 of fermentation, the lactic acid bacteria population became dominant and persisted together with yeasts throughout the fermentation period. The lactic acid bacteria isolated (343 isolates were identified as L. casei, L. rhamnosus, L. paracasei, L. plantarum, L. lactis subsp. lactis, E. faecalis, E. faecium and E. durans. The dominant species was L. plantarum. Yeasts were isolated from all samples (32 isolates and were identified as Saccharomyces cerevisiae or Candida parapsilosis. Also, in this study we reported that brine solutions obtained at the end of olive fermentation were able to stimulate the growth of several L. plantarum strainsLa microflora de las aceitunas verdes fermentadas naturalmente elaboradas en Argelia Occidental fue estudiada en períodos de fermentación de 15, 60 y 90 días. Diferentes microorganismos (bacterias aeróbicas, coliformes, estafilococos, bacterias del ácido láctico, lactobacilos, enterococos, levaduras, psicotrofos y bacterias lipolíticas fueron detectados a los 15 y 60 días de fermentación. Después de 90 días de fermentación (pH 4.40, la población de bacterias lácticas se hizo dominante y persistió junto con las levaduras a lo largo de todo el proceso. Las bacterias lácticas aisladas (343 fueron identificadas como L. casei, L. rhamnosus, L. paracasei, L. plantarum, L. lactis subsp. lactis, E. faecalis, E. faecium y E. durans. La especie dominante fue L. plantarum. Las levaduras aisladas (32 de todas las muestras fueron identificadas como Saccharomyces cerevisiae o Candida parapsilosis. También se recoge en este estudio que las soluciones de salmuera obtenidas al final de fermentación de aceitunas verdes fueron capaces de estimular el crecimiento de varias cepas de L. plantarum.

  7. The Microbial Karst Sulfuric Acid Dynamo

    Science.gov (United States)

    Lyon, E.; Meyer, K.; Koffman, B.; Galdenzi, S.; Macalady, J.

    2004-12-01

    The original model for sulfuric acid speleogenesis attributes limestone dissolution to the oxidation of gaseous H2S to sulfuric acid on limestone cave walls (Egemeier 1981). This model has recently been reexamined in Lower Kane Cave, Wyoming (USA), where the most intense limestone dissolution appears to be the result of microbial colonization of limestone surfaces below the water table (Engel et al. 2004). In contrast, sulfuric acid speleogenesis in the Frasassi Caves (Italy) is equally intense above and below the water table, and is mediated not only by sulfur-oxidizing bacteria but by a complex community of sulfur cycling microorganisms including diverse sulfate-reducing bacteria. The sulfate-reducing bacteria were identified in 16S rDNA clone libraries from both cave walls and cave stream biofilms. These findings suggest a new model for sulfuric acid speleogenesis in which a full range of oxidants and reductants available to indigenous sulfur-cycling microbial communities control the extent of sulfur recycling and sulfuric acid production at limestone surfaces.

  8. Survival of potential probiotic lactic acid bacteria on fermented green table olives during packaging in polyethylene pouches at 4 and 20 °C.

    Science.gov (United States)

    Blana, Vasiliki A; Polymeneas, Napoleon; Tassou, Chrysoula C; Panagou, Efstathios Z

    2016-02-01

    The survival of selected lactic acid bacteria (LAB) with in vitro probiotic potential was studied during storage of cv. Halkidiki green olives previously subjected to inoculated Spanish-style fermentation. After fermentation olives were packed in polyethylene pouches, covered with freshly prepared brine (9%, w/v, NaCl), acidified with 2‰ (w/v) citric acid and 1.5‰ (w/v) ascorbic acid, and stored at 4 and 20 °C for 357 days. Four packing treatments were studied, namely olives previously fermented by (i) the indigenous microbiota (control); (ii) Lactobacillus pentosus B281; (iii) Lactobacillus plantarum B282; and (iv) a co-culture of both LAB strains. Microbiological analyses were performed on the olives in parallel with physicochemical changes (pH, titratable acidity, salt content, aw and colour) at the early (day 1), middle (day 197) and final stage (day 357) of storage, as well as sensory evaluation at the end of the storage. The survival of probiotic strains was confirmed by Pulsed Field Gel Electrophoresis (PFGE). LAB decreased throughout storage reaching a final population of ca. 3.5-4.0 log CFU/g and 4.5-5.0 log CFU/g at 4 and 20 °C, respectively. The pH values ranged between 3.90 and 4.61 during storage depending on packaging condition. PFGE analysis revealed that L. pentosus B281 and L. plantarum B282 showed a high survival rate with a recovery of 100 and 96%, respectively, at 4 °C, and less than 20% for both strains at 20 °C. Finally, in the packing treatment with a co-culture of both strains, L. pentosus dominated over L. plantarum throughout storage at both temperatures. PMID:26678132

  9. Sulfur Mustard

    Science.gov (United States)

    ... Case Definition: Caustic or Corrosive Agents Incapacitating Agents Metals Nerve Agents Pulmonary Agents Riot Control Agents Toxic ... is exposure to sulfur mustard vapor. Extensive skin burning can be fatal. Extensive breathing in of the ...

  10. Biological and Abiological Sulfur Reduction at High Temperatures †

    OpenAIRE

    Belkin, Shimshon; Wirsen, Carl O.; Jannasch, Holger W.

    1985-01-01

    Reduction of elemental sulfur was studied in the presence and absencè of thermophilic sulfur-reducing bacteria, at temperatures ranging from 65 to 110°C, in anoxic artificial seawater media. Above 80°C, significant amounts of sulfide were produced abiologically at linear rates, presumably by the disproportionation of sulfur. These rates increased with increasing temperature and pH and were enhanced by yeast extract. In the same medium, the sulfur respiration of two recent thermophilic isolate...

  11. Biodiversity, metabolism and applications of acidophilic sulfur-metabolizing microorganisms.

    Science.gov (United States)

    Dopson, Mark; Johnson, D Barrie

    2012-10-01

    Extremely acidic, sulfur-rich environments can be natural, such as solfatara fields in geothermal and volcanic areas, or anthropogenic, such as acid mine drainage waters. Many species of acidophilic bacteria and archaea are known to be involved in redox transformations of sulfur, using elemental sulfur and inorganic sulfur compounds as electron donors or acceptors in reactions involving between one and eight electrons. This minireview describes the nature and origins of acidic, sulfur-rich environments, the biodiversity of sulfur-metabolizing acidophiles, and how sulfur is metabolized and assimilated by acidophiles under aerobic and anaerobic conditions. Finally, existing and developing technologies that harness the abilities of sulfur-oxidizing and sulfate-reducing acidophiles to extract and capture metals, and to remediate sulfur-polluted waste waters are outlined. PMID:22510111

  12. Growth of Thiobacillus ferrooxidans on elemental sulfur

    International Nuclear Information System (INIS)

    Growth kinetics of Thiobacillus ferrooxidans in batch cultures, containing prills of elementary sulfur as the sole energy source, were studied by measuring the incorporation of radioactive phosphorus in free and adsorbed bacteria. The data obtained indicate an initial exponential growth of the attached bacteria until saturation of the susceptible surface was reached, followed by a linear release of free bacteria due to successive replication of a constant number of adsorbed bacteria. These adsorbed bacteria could continue replication provided the colonized prills were transferred to fresh medium each time the stationary phase was reached. The bacteria released from the prills were unable to multiply, and in the medium employed they lost viability with a half-live of 3.5 days. The spreading of the progeny on the surface was followed by staining the bacteria on the prills with crystal violet; this spreading was not uniform but seemed to proceed through distortions present in the surface. The specific growth rate of T. ferrooxidans ATCC 19859 was about 0.5 day-1, both before and after saturation of the sulfur surface. The growth of adsorbed and free bacteria in medium containing both ferrous iron and elementary sulfur indicated that T. ferrooxidans can simultaneously utilize both energy sources

  13. Marine Bacteria from Danish Coastal Waters Show Antifouling Activity against the Marine Fouling Bacterium Pseudoalteromonas sp. Strain S91 and Zoospores of the Green Alga Ulva australis Independent of Bacteriocidal Activity

    DEFF Research Database (Denmark)

    Bernbom, Nete; Ng, Yoke Yin

    2011-01-01

    The aims of this study were to determine if marine bacteria from Danish coastal waters produce antifouling compounds and if antifouling bacteria could be ascribed to specific niches or seasons. We further assess if antibacterial effect is a good proxy for antifouling activity. We isolated 110 bacteria with anti-Vibrio activity from different sample types and locations during a 1-year sampling from Danish coastal waters. The strains were identified as Pseudoalteromonas, Phaeobacter, and Vibrionaceae based on phenotypic tests and partial 16S rRNA gene sequence similarity. The numbers of bioactive bacteria were significantly higher in warmer than in colder months. While some species were isolated at all sampling locations, others were niche specific. We repeatedly isolated Phaeobacter gallaeciensis at surfaces from one site and Pseudoalteromonas tunicata at two others. Twenty-two strains, representing the major taxonomic groups, different seasons, and isolation strategies, were tested for antiadhesive effect against the marine biofilm-forming bacterium Pseudoalteromonas sp. strain S91 and zoospores of the green alga Ulva australis. The antiadhesive effects were assessed by quantifying the number of strain S91 or Ulva spores attaching to a preformed biofilm of each of the 22 strains. The strongest antifouling activity was found in Pseudoalteromonas strains. Biofilms of Pseudoalteromonas piscicida, Pseudoalteromonas tunicata, and Pseudoalteromonas ulvae prevented Pseudoalteromonas S91 from attaching to steel surfaces. P. piscicida killed S91 bacteria in the suspension cultures, whereas P. tunicata and P. ulvae did not; however, they did prevent adhesion by nonbactericidal mechanism(s). Seven Pseudoalteromonas species, including P. piscicida and P. tunicata, reduced the number of settling Ulva zoospores to less than 10% of the number settling on control surfaces. The antifouling alpP gene was detected only in P. tunicata strains (with purple and yellow pigmentation), so other compounds/mechanisms must be present in theother Pseudoalteromonas strains with antifouling activity.

  14. Sulfur cycle

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.

    Cowles HC (1899) The ecological relations of the vegetation on the sand Whittaker RJ, Bush MB, and Richards K (1989) Plant recolonization and Panaji, India Fluxes of the Global Biogeochemical Sulfur Cycle Summary Further Reading 3424 Global Ecology... of the Kenya coast. Palaeontology 23: 1–37. Drury WH and Nisbet ICT (1973) Succession. Journal of the Arnold Arboretum 54: 331–368. Egler FE (1954) Vegetation science concepts. I. Initial floristic composition, a factor in old-field development. Vegetatio 4...

  15. Electronic energy transfer involving carotenoid pigments in chlorosomes of two green bacteria: Chlorobium tepidum and Chloroflexus aurantiacus

    DEFF Research Database (Denmark)

    Melø, T B; Frigaard, N-U; Matsuura, K; Razi Naqvi, K

    2000-01-01

    Electronic energy transfer processes in chlorosomes isolated from the green sulphur bacterium Chlorobium tepidum and from the green filamentous bacterium Chloroflexus aurantiacus have been investigated. Steady-state fluorescence excitation spectra and time-resolved triplet-minus-singlet (TmS) spectra, recorded at ambient temperature and under non-reducing or reducing conditions, are reported. The carotenoid (Car) pigments in both species transfer their singlet excitation to bacteriochlorophyll c...

  16. Sulfur in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Uzhdavini, E.P.; Murzakaev, F.G.

    1984-02-01

    Various aspects of the problem of sulfur pollution of the environment are reviewed. Particular consideration is given to sources of sulfur pollution; the diffusion of sulfur-containing compounds in emissions from industrial plants; and applications of sulfur compounds in industry. Possible ways to control sulfur pollutants are examined. 6 references.

  17. The Microworld of Marine-Bacteria

    DEFF Research Database (Denmark)

    JØRGENSEN, BB

    1995-01-01

    Microsensor studies show that the marine environment in the size scale of bacteria is physically and chemically very different from the macroenvironment. The microbial world of the sediment-water interface is thus dominated by water viscosity and steep diffusion gradients. Because of the diverse metabolism types, bacteria in the mostly anoxic sea floor play an important role in the major element cycles of the ocean. The communities of giant, filamentous sulfur bacteria that live in the deep-sea ...

  18. Uses of lunar sulfur

    Energy Technology Data Exchange (ETDEWEB)

    Vaniman, D.T.; Pettit, D.R.; Heiken, G.

    1988-01-01

    Sulfur and sulfur compounds have a wide range of applications for their fluid, electrical, chemical and biochemical properties. Although low in abundance on the Moon (/approximately/0.1% in mare soils), sulfur is surface-correlated and relatively extractable. Co-production of sulfur during oxygen extraction from ilmenite-rich soils could yield sulfur in masses up to 10% of the mass of oxygen produced. Sulfur deserves serious consideration as a lunar resource. 29 refs., 3 figs.

  19. Effect of acidic pH on flow cytometric detection of bacteria stained with SYBR Green I and their distinction from background

    Science.gov (United States)

    Baldock, Daniel; Nebe-von-Caron, Gerhard; Bongaerts, Roy; Nocker, Andreas

    2013-12-01

    Unspecific background caused by biotic or abiotic particles, cellular debris, or autofluorescence is a well-known interfering parameter when applying flow cytometry to the detection of microorganisms in combination with fluorescent dyes. We present here an attempt to suppress the background signal intensity and thus to improve the detection of microorganisms using the nucleic acid stain SYBR® Green I. It has been observed that the fluorescent signals from SYBR Green I are greatly reduced at acidic pH. When lowering the pH of pre-stained samples directly prior to flow cytometric analysis, we hypothesized that the signals from particles and cells with membrane damage might therefore be reduced. Signals from intact cells, temporarily maintaining a neutral cytosolic pH, should not be affected. We show here that this principle holds true for lowering background interference, whereas the signals of membrane-compromised dead cells are only affected weakly. Signals from intact live cells at low pH were mostly comparable to signals without acidification. Although this study was solely performed with SYBR® Green I, the principle of low pH flow cytometry (low pH-FCM) might hold promise when analyzing complex matrices with an abundance of non-cellular matter, especially when expanded to non-DNA binding dyes with a stronger pH dependence of fluorescence than SYBR Green I and a higher pKa value.

  20. Effect of acidic pH on flow cytometric detection of bacteria stained with SYBR Green I and their distinction from background

    International Nuclear Information System (INIS)

    Unspecific background caused by biotic or abiotic particles, cellular debris, or autofluorescence is a well-known interfering parameter when applying flow cytometry to the detection of microorganisms in combination with fluorescent dyes. We present here an attempt to suppress the background signal intensity and thus to improve the detection of microorganisms using the nucleic acid stain SYBR® Green I. It has been observed that the fluorescent signals from SYBR Green I are greatly reduced at acidic pH. When lowering the pH of pre-stained samples directly prior to flow cytometric analysis, we hypothesized that the signals from particles and cells with membrane damage might therefore be reduced. Signals from intact cells, temporarily maintaining a neutral cytosolic pH, should not be affected. We show here that this principle holds true for lowering background interference, whereas the signals of membrane-compromised dead cells are only affected weakly. Signals from intact live cells at low pH were mostly comparable to signals without acidification. Although this study was solely performed with SYBR® Green I, the principle of low pH flow cytometry (low pH-FCM) might hold promise when analyzing complex matrices with an abundance of non-cellular matter, especially when expanded to non-DNA binding dyes with a stronger pH dependence of fluorescence than SYBR Green I and a higher pKa value. (paper)

  1. Vertical distribution of bacteria and intensity of microbiological processes in two stratified gypsum Karst Lakes in Lithuania

    Directory of Open Access Journals (Sweden)

    Krevs A.

    2011-08-01

    Full Text Available Physical-chemical parameters and the vertical distribution of bacteria and organic matter production-destruction processes were studied during midsummer stratification in two karst lakes (Kirkilai and Ramunelis located in northern Lithuania. The lakes were characterized by high sulfate concentrations (369–1248 mg·L-1. The O2/H2S intersection zone formed at 2–3 m depth. In Lake Kirkilai, the highest bacterial densities (up to 8.7 × 106 cell·mL-1 occurred at the O2/H2S intersection zone, whereas in Lake Ramunelis the highest densities were observed in the anoxic hypolimnion (up to 11 × 106 cell·mL-1. Pigment analysis revealed that green sulfur bacteria dominated in the microaerobic–anaerobic water layers in both lakes. The most intensive development of sulfate-reducing bacteria was observed in the anaerobic layer. Photosynthetic production of organic matter was highest in the upper layer. Rates of sulfate reduction reached 0.23 mg S2?·dm3·d-1 in the microaerobic-anaerobic water layer and 1.97 mg S2?·dm3·d-1 in sediments. Karst lakes are very sensitive to organic pollution, because under such impact in the presence of high sulfate amounts, sulfate reduction may become very intensive and, consequently, the increase in hydrogen sulfide and development of sulfur cycle bacteria may reduce the variety of other hydrobionts.

  2. An isotopic biogeochemical study of the Green River oil shale

    Science.gov (United States)

    Collister, J. W.; Summons, R. E.; Lichtfouse, E.; Hayes, J. M.

    1992-01-01

    Thirty-five different samples from three different sulfur cycles were examined in this stratigraphically oriented study of the Shell 22x-l well (U.S.G.S. C177 core) in the Piceance Basin, Colorado. Carbon isotopic compositions of constituents of Green River bitumens indicate mixing of three main components: products of primary photoautotrophs and their immediate consumers (delta approximately -30% vs PDB), products of methanotrophic bacteria (delta approximately -85%), and products of unknown bacteria (delta approximately -40%). For individual compounds synthesized by primary producers, delta-values ranged from -28 to -32%. 13C contents of individual primary products (beta-carotane, steranes, acyclic isoprenoids, tricyclic triterpenoids) were not closely correlated, suggesting diverse origins for these materials. 13C contents of numerous hopanoids were inversely related to sulfur abundance, indicating that they derived both from methanotrophs and from other bacteria, with abundances of methanotrophs depressed when sulfur was plentiful in the paleoenvironment. gamma-Cerane coeluted with 3 beta(CH3),17 alpha(H),21 beta(H)-hopane, but delta-values could be determined after deconvolution. gamma-Cerane (delta approximately -25%) probably derives from a eukaryotic heterotroph grazing on primary materials, the latter compound (delta approximately -90%) must derive from methanotrophic organisms. 13C contents of n-alkanes in bitumen differed markedly from those of paraffins generated pyrolytically. Isotopic and quantitative relationships suggest that alkanes released by pyrolysis derived from a resistant biopolymer of eukaryotic origin and that this was a dominant constituent of total organic carbon.

  3. Organic Sulfur Gas Production in Sulfidic Caves

    Science.gov (United States)

    Stern, L. A.; Engel, A. S.; Bennett, P. C.

    2001-12-01

    Lower Kane Cave, Big Horn Basin, WY, permits access to an environment where anaerobic sulfide-rich groundwater meets the aerobic vadose zone. At this interface microorganisms thrive on diverse metabolic pathways including autotrophic sulfur oxidation, sulfate reduction, and aerobic heterotrophy. Springs introduce groundwater rich in H2S to the cave where it both degasses into the cave atmosphere and is used by chemautotrophic sulfur oxidizing bacteria in the cave spring and stream habitat. The cave atmosphere in the immediate vicinity of the springs has elevated levels of CO2, H2S and methane, mirroring the higher concentration of H2S and methane in the spring water. The high CO2 concentrations are attenuated toward the two main sources of fresh air, the cave entrance and breathing holes at the rear of the cave. Conventional toxic gas monitors permit estimations of H2S concentrations, but they have severe cross sensitivity with other reduced sulfur gases, and thus are inadequate for characterization of sulfur cave gases. However employment of a field-based GC revealed elevated concentrations of carbonyl sulfide in cave atmosphere. Cultures of microorganisms collected from the cave optimized for enriching fermenters and autotrophic and heterophic sulfate reducing bacteria each produced carbonyl sulfide suggesting a biogenic in origin of the COS in addition to H2S. Enrichment cultures also produced methanethiol (methyl mercaptan) and an additional as yet undetermined volatile organic sulfur compound. In culture, the organo-sulfur compounds were less abundant than H2S, whereas in the cave atmosphere the organo-sulfur compounds were the dominant sulfur gases. Thus, these organo-sulfur gases may prove to be important sources of both reduced sulfur and organic carbon to microorganisms living on the cave wall in a subaerial habitat. Moreover groundwater has not yet been recognized as a source of sulfur gases to the atmosphere, but with the abundance of sulfidic groundwater, this environment may prove to be important to the global sulfur cycle and its influence of the global radiation budget.

  4. Split of sodium and sulfur in a Kraft mill and internal production of sulfuric acid and sodium hydroxide

    OpenAIRE

    Lundblad, Helena

    2012-01-01

    The removal of lignin in a Kraft pulp mill, with the aim to utilize the lignin as more value added green product than just firing lignin in black liquor, is possible with a LignoBoost plant. The LignoBoost plant uses sulfuric acid in the process and this results in an increased net input of sulfur to the pulp mills recovery cycle. The sodium/sulfur balance in a Kraft pulp mill is an important factor to be able to run a mill optimal. The increased input of sulfur into the mill when implementin...

  5. Methanotrophic bacteria.

    OpenAIRE

    Hanson, R. S.; Hanson, T E

    1996-01-01

    Methane-utilizing bacteria (methanotrophs) are a diverse group of gram-negative bacteria that are related to other members of the Proteobacteria. These bacteria are classified into three groups based on the pathways used for assimilation of formaldehyde, the major source of cell carbon, and other physiological and morphological features. The type I and type X methanotrophs are found within the gamma subdivision of the Proteobacteria and employ the ribulose monophosphate pathway for formaldehy...

  6. Autotrophy of green non-sulphur bacteria in hot spring microbial mats: biological explanations for isotopically heavy organic carbon in the geological record

    Science.gov (United States)

    van der Meer, M. T.; Schouten, S.; de Leeuw, J. W.; Ward, D. M.

    2000-01-01

    Inferences about the evidence of life recorded in organic compounds within the Earth's ancient rocks have depended on 13C contents low enough to be characteristic of biological debris produced by the well-known CO2 fixation pathway, the Calvin cycle. 'Atypically' high values have been attributed to isotopic alteration of sedimentary organic carbon by thermal metamorphism. We examined the possibility that organic carbon characterized by a relatively high 13C content could have arisen biologically from recently discovered autotrophic pathways. We focused on the green non-sulphur bacterium Chloroflexus aurantiacus that uses the 3-hydroxypropionate pathway for inorganic carbon fixation and is geologically significant as it forms modern mat communities analogous to stromatolites. Organic matter in mats constructed by Chloroflexus spp. alone had relatively high 13C contents (-14.9%) and lipids diagnostic of Chloroflexus that were also isotopically heavy (-8.9% to -18.5%). Organic matter in mats constructed by Chloroflexus in conjunction with cyanobacteria had a more typical Calvin cycle signature (-23.5%). However, lipids diagnostic of Chloroflexus were isotopically enriched (-15.1% to -24.1%) relative to lipids typical of cyanobacteria (-33.9% to -36.3%). This suggests that, in mats formed by both cyanobacteria and Chloroflexus, autotrophy must have a greater effect on Chloroflexus carbon metabolism than the photoheterotrophic consumption of cyanobacterial photosynthate. Chloroflexus cell components were also selectively preserved. Hence, Chloroflexus autotrophy and selective preservation of its products constitute one purely biological mechanism by which isotopically heavy organic carbon could have been introduced into important Precambrian geological features.

  7. Thermophilic Carbon-Sulfur-Bond-Targeted Biodesulfurization

    Science.gov (United States)

    Konishi, J.; Ishii, Y.; Onaka, T.; Okumura, K.; Suzuki, M.

    1997-01-01

    Petroleum contains many heterocyclic organosulfur compounds refractory to conventional hydrodesulfurization carried out with chemical catalysts. Among these, dibenzothiophene (DBT) and DBTs bearing alkyl substitutions are representative compounds. Two bacterial strains, which have been identified as Paenibacillus strains and which are capable of efficiently cleaving carbon-sulfur (C--S) bonds in DBT at high temperatures, have been isolated for the first time. Upon attacking DBT and its various methylated derivatives at temperatures up to 60(deg)C, both growing and resting cells of these bacteria can release sulfur atoms as sulfate ions and leave the monohydroxylated hydrocarbon moieties intact. Moreover, when either of these paenibacilli was incubated at 50(deg)C with light gas oil previously processed through hydrodesulfurization, the total sulfur content in the oil phase clearly decreased. PMID:16535672

  8. Chlamydomonas Flavodiiron Proteins Facilitate Acclimation to Anoxia During Sulfur Deprivation.

    Science.gov (United States)

    Jokel, Martina; Kosourov, Sergey; Battchikova, Natalia; Tsygankov, Anatoly A; Aro, Eva Mari; Allahverdiyeva, Yagut

    2015-08-01

    The flavodiiron proteins (FDPs) are involved in the detoxification of oxidative compounds, such as nitric oxide (NO) or O(2) in Archaea and Bacteria. In cyanobacteria, the FDPs Flv1 and Flv3 are essential in the light-dependent reduction of O(2) downstream of PSI. Phylogenetic analysis revealed that two genes (flvA and flvB) in the genome of Chlamydomonas reinhardtii show high homology to flv1 and flv3 genes of the cyanobacterium Synechocystis sp. PCC 6803. The physiological role of these FDPs in eukaryotic green algae is not known, but it is of a special interest since these phototrophic organisms perform oxygenic photosynthesis similar to higher plants, which do not possess FDP homologs. We have analyzed the levels of flvA and flvB transcripts in C. reinhardtii cells under various environmental conditions and showed that these genes are highly expressed under ambient CO(2) levels and during the early phase of acclimation to sulfur deprivation, just before the onset of anaerobiosis and the induction of efficient H(2) photoproduction. Importantly, the increase in transcript levels of the flvA and flvB genes was also corroborated by protein levels. These results strongly suggest the involvement of FLVA and FLVB proteins in alternative electron transport. PMID:26063391

  9. ADVANCED SULFUR CONTROL CONCEPTS

    Energy Technology Data Exchange (ETDEWEB)

    Apostolos A. Nikolopoulos; Santosh K. Gangwal; William J. McMichael; Jeffrey W. Portzer

    2003-01-01

    Conventional sulfur removal in integrated gasification combined cycle (IGCC) power plants involves numerous steps: COS (carbonyl sulfide) hydrolysis, amine scrubbing/regeneration, Claus process, and tail-gas treatment. Advanced sulfur removal in IGCC systems involves typically the use of zinc oxide-based sorbents. The sulfides sorbent is regenerated using dilute air to produce a dilute SO{sub 2} (sulfur dioxide) tail gas. Under previous contracts the highly effective first generation Direct Sulfur Recovery Process (DSRP) for catalytic reduction of this SO{sub 2} tail gas to elemental sulfur was developed. This process is currently undergoing field-testing. In this project, advanced concepts were evaluated to reduce the number of unit operations in sulfur removal and recovery. Substantial effort was directed towards developing sorbents that could be directly regenerated to elemental sulfur in an Advanced Hot Gas Process (AHGP). Development of this process has been described in detail in Appendices A-F. RTI began the development of the Single-step Sulfur Recovery Process (SSRP) to eliminate the use of sorbents and multiple reactors in sulfur removal and recovery. This process showed promising preliminary results and thus further process development of AHGP was abandoned in favor of SSRP. The SSRP is a direct Claus process that consists of injecting SO{sub 2} directly into the quenched coal gas from a coal gasifier, and reacting the H{sub 2}S-SO{sub 2} mixture over a selective catalyst to both remove and recover sulfur in a single step. The process is conducted at gasifier pressure and 125 to 160 C. The proposed commercial embodiment of the SSRP involves a liquid phase of molten sulfur with dispersed catalyst in a slurry bubble-column reactor (SBCR).

  10. Greening economy, greening people

    OpenAIRE

    Bandzeladze, T.

    2013-01-01

    Green economy is one that generates increasing prosperity while maintaining the natural systems that sustain us. The greening of economies is not generally a drag on growth but rather a new engine of growth; that it is a net generator of decent jobs, and that it is also a vital strategy for the elimination of persistent poverty. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/31039

  11. Advanced sulfur control concepts

    Energy Technology Data Exchange (ETDEWEB)

    Gangwal, S.K.; Turk, B.S.; Gupta, R.P.

    1995-11-01

    Regenerable metal oxide sorbents, such as zinc titanate, are being developed to efficiently remove hydrogen sulfide (H{sub 2}S) from coal gas in advanced power systems. Dilute air regeneration of the sorbents produces a tailgas containing a few percent sulfur dioxide (SO{sub 2}). Catalytic reduction of the SO{sub 2} to elemental sulfur with a coal gas slipstream using the Direct Sulfur Recovery Process (DSRP) is a leading first-generation technology. Currently the DSRP is undergoing field testing at gasifier sites. The objective of this study is to develop second-generation processes that produce elemental sulfur without coal gas or with limited use. Novel approaches that were evaluated to produce elemental sulfur from sulfided sorbents include (1) sulfur dioxide (SO{sub 2}) regeneration, (2) substoichiometric (partial) oxidation, (3) steam regeneration followed by H{sub 2}S oxidation, and (4) steam-air regeneration. Preliminary assessment of these approaches indicated that developing SO{sub 2} regeneration faced the fewest technical and economic problems among the four process options. Elemental sulfur is the only likely product of SO{sub 2} regeneration and the SO{sub 2} required for the regeneration can be obtained by burning a portion of the sulfur produced. Experimental efforts have thus been concentrated on SO{sub 2}-based regeneration processes. Results from laboratory investigations are presented and discussed.

  12. Marine Bacteria from Danish Coastal Waters Show Antifouling Activity against the Marine Fouling Bacterium Pseudoalteromonas sp. Strain S91 and Zoospores of the Green Alga Ulva australis Independent of Bacteriocidal Activity

    DEFF Research Database (Denmark)

    Bernbom, Nete; Ng, Yoke Yin; Kjelleberg, Staffan; Harder, Tilmann; Gram, Lone

    2011-01-01

    The aims of this study were to determine if marine bacteria from Danish coastal waters produce antifouling compounds and if antifouling bacteria could be ascribed to specific niches or seasons. We further assess if antibacterial effect is a good proxy for antifouling activity. We isolated 110 bacteria with anti-Vibrio activity from different sample types and locations during a 1-year sampling from Danish coastal waters. The strains were identified as Pseudoalteromonas, Phaeobacter, and Vibrionac...

  13. Biogenic hydroxysulfate green rust, a potential electron acceptor for SRB activity

    Science.gov (United States)

    Zegeye, Asfaw; Huguet, Lucie; Abdelmoula, Mustapha; Carteret, Cédric; Mullet, Martine; Jorand, Frédéric

    2007-11-01

    Microbiological reduction of a biogenic sulfated green rust (GR2(SO42-)), was examined using a sulfate reducing bacterium ( Desulfovibrio alaskensis). Experiments investigated whether GR2(SO42-) could serve as a sulfate source for D. alaskensis anaerobic respiration by analyzing mineral transformation. Batch experiments were conducted using lactate as the electron donor and biogenic GR2(SO42-) as the electron acceptor, at circumneutral pH in unbuffered medium. GR2(SO42-) transformation was monitored with time by X-ray diffraction (XRD), Transmission Mössbauer Spectroscopy (TMS), Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS), Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). The reduction of sulfate anions and the formation of iron sulfur mineral were clearly identified by XPS analyses. TMS showed the formation of additional mineral as green rust (GR) and vivianite. XRD analyses discriminated the type of the newly formed GR as GR1. The formed GR1 was GR1(CO32-) as indicated by DRIFTS analysis. Thus, the results presented in this study indicate that D. alaskensis cells were able to use GR2(SO42-) as an electron acceptor. GR1(CO32-), vivianite and an iron sulfur compound were formed as a result of GR2(SO42-) reduction by D. alaskensis. Hence, in environments where geochemical conditions promote biogenic GR2(SO42-) formation, this mineral could stimulate the anaerobic respiration of sulfate reducing bacteria.

  14. Fermentation, Hydrogen, and Sulfur Metabolism in Multiple Uncultivated Bacterial Phyla

    Energy Technology Data Exchange (ETDEWEB)

    Wrighton, Kelly C.; Thomas, Brian C.; Sharon, I.; Miller, Christopher S.; Castelle, Cindy; VerBerkmoes, Nathan C.; Wilkins, Michael J.; Hettich, Robert L.; Lipton, Mary S.; Williams, Kenneth H.; Long, Philip E.; Banfield, Jillian F.

    2012-09-27

    BD1-5, OP11, and OD1 bacteria have been widely detected in anaerobic environments, but their metabolisms remain unclear owing to lack of cultivated representatives and minimal genomic sampling. We uncovered metabolic characteristics for members of these phyla, and a new lineage, PER, via cultivation-independent recovery of 49 partial to near-complete genomes from an acetate-amended aquifer. All organisms were nonrespiring anaerobes predicted to ferment. Three augment fermentation with archaeal-like type II and III ribulose-1,5-bisphosphate carboxylase-oxygenase (RuBisCO) that couples adenosine monophosphate salvage with CO2 fixation, a pathway previously not described in Bacteria. Members of OD1 reduce sulfur and may pump protons using archaeal-type hydrogenases. For six organisms, the UGA stop codon is translated as tryptophan. All bacteria studied here may play previously unrecognized roles in hydrogen production, sulfur cycling, and fermentation of refractory sedimentary carbon.

  15. Sulfur Dioxide Emissions

    Science.gov (United States)

    This indicator presents regional and national sulfur dioxide (SO2) emissions data for 1990, 1996 to 2002, and 2005. SO2 emissions (combined with atmospheric fate and transport processes) determine corresponding ambient SO2 concentration levels ...

  16. Sulfur and climate changes

    International Nuclear Information System (INIS)

    The sulfur released by some industries and by the phytoplankton acts on the environment: it cools the earth while forming tiny particles which spread the solar light and send it back towards space. The resulting cooling compensates partly the global warming due to greenhouse effect. The sulfur compounds are also liable for the acid rains, the mist formation and the rarefaction of atmospheric ozone. 3 refs., 4 figs

  17. Dense populations of a giant sulfur bacterium in Namibian shelf sediments

    DEFF Research Database (Denmark)

    Schulz, HN; Brinkhoff, T.

    1999-01-01

    A previously unknown giant sulfur bacterium is abundant in sediments underlying the oxygen minimum zone of the Benguela Current upwelling system. The bacterium has a spherical cell that exceeds by up to 100-fold the biovolume of the largest known prokaryotes. On the basis of 16S ribosomal DNA sequence data, these bacteria are closely related to the marine filamentous sulfur bacteria Thioploca, abundant in the upwelling area off Chile and Peru. Similar to Thioploca, the giant bacteria oxidize sulfide with nitrate that is accumulated to less than or equal to 800 millimolar in a central vacuole.

  18. Production of sulfuric acid and installation therefor

    OpenAIRE

    Arpentinier, Philippe; Dumont, Marie-Noëlle; Kalitventzeff, Boris

    1998-01-01

    In the production of sulfuric acid by (a) oxidizing a sulfurous material with an oxidant to obtain sulfur dioxide, (b) catalytically oxidizing this with oxygen to obtain sulfur trioxide and (c) producing sulfuric acid and a waste gas, at least part of the waste gas is recycled to the first step. The fabrication of sulfuric acid consists of: (a) producing sulfur dioxide from a sulfur based material and an oxidant; (b) converting catalytically the sulfur dioxide into trioxide in a catalytic con...

  19. Quadruple sulfur isotope constraints on the origin and cycling of volatile organic sulfur compounds in a stratified sulfidic lake

    Science.gov (United States)

    Oduro, Harry; Kamyshny, Alexey; Zerkle, Aubrey L.; Li, Yue; Farquhar, James

    2013-11-01

    We have quantified the major forms of volatile organic sulfur compounds (VOSCs) distributed in the water column of stratified freshwater Fayetteville Green Lake (FGL), to evaluate the biogeochemical pathways involved in their production. The lake's anoxic deep waters contain high concentrations of sulfate (12-16 mmol L-1) and sulfide (0.12 ?mol L-1 to 1.5 mmol L-1) with relatively low VOSC concentrations, ranging from 0.1 nmol L-1 to 2.8 ?mol L-1. Sulfur isotope measurements of combined volatile organic sulfur compounds demonstrate that VOSC species are formed primarily from reduced sulfur (H2S/HS-) and zero-valent sulfur (ZVS), with little input from sulfate. Thedata support a role of a combination of biological and abiotic processes in formation of carbon-sulfur bonds between reactive sulfur species and methyl groups of lignin components. These processes are responsible for very fast turnover of VOSC species, maintaining their low levels in FGL. No dimethylsulfoniopropionate (DMSP) was detected by Electrospray Ionization Mass Spectrometry (ESI-MS) in the lake water column or in planktonic extracts. These observations indicate a pathway distinct from oceanic and coastal marine environments, where dimethylsulfide (DMS) and other VOSC species are principally produced via the breakdown of DMSP by plankton species.

  20. Rumen bacteria

    International Nuclear Information System (INIS)

    The rumen is the most extensively studied gut community and is characterized by its high population density, wide diversity and complexity of interactions. This complex, mixed microbial culture is comprised of prokaryote organisms including methane-producing archaebacteria, eukaryote organisms, such as ciliate and flagellate protozoa, anaerobic phycomycete fungi and bacteriophage. Bacteria are predominant (up to 1011 viable cells per g comprising 200 species) but a variety of ciliate protozoa occur widely (104-106/g distributed over 25 genera). The anaerobic fungi are also widely distributed (zoospore population densities of 102-104/g distributed over 5 genera). The occurrence of bacteriophage is well documented (107-109 particles/g). This section focuses primarily on the widely used methods for the cultivation and the enumeration of rumen microbes, especially bacteria, which grow under anaerobic conditions. Methods that can be used to measure hydrolytic enzymes (cellulases, xylanases, amylases and proteinases) are also described, along with cell harvesting and fractionation procedures. Brief reference is also made to fungi and protozoa, but detailed explanations for culturing and enumerating these microbes is presented in Chapters 2.4 and 2.5

  1. Metaphysical green

    DEFF Research Database (Denmark)

    Earon, Ofri

    “Sensation of Green is about the mental process like touching, seeing, hearing, or smelling, resulting from the immediate stimulation of landscape forms, plants, trees, wind and water. Sensation of Green triggers a feeling of scale, cheerfulness, calmness and peace. The spatial performance of Sensation of Green is created by a physical interaction between the language of space and the language of nature” The notion of Sensation of Green was developed through a previous study ‘Learning from the Summer House’ investigating the unique architectural characteristics of the Danish summer houses. The idea of the concept is a mutual participation of nature in architecture meaning that landscape features become tools to design a built space. The paper develops the concept further focusing on the scale of a single residential unit. The paper argues that the concept of Sensation of Green is flexible to adapt to urban environment. It explores the potential of Sensation of Green in the city. The paper questions whether the Sensation of Green could introduce a new spectrum of greens, beside the real green. It develops the term of metaphysical green – does green have to be green or can it be only the Sensation of Green? Three existing examples are agents to this discussion. The first example is a Danish summer house. The other two are international urban examples. While the summer house articulates the original meaning of Sensation of Green, the urban examples illustrate its urban context. The first example is a tiny Danish summer house from 1918 . The second example is ‘House before House’ , in Tokyo. The third example is a prefabricated house ‘CHU’ . The analysis evaluates the characteristics of diverse tones of green – from green image to green sensation. The analysis is based on the original definition of the concept defined during the summer house study. Learning from these single residential units, the paper ends by questioning the potential of the concept of Sensation of Green concerning a larger urban typology.

  2. Membrane damage of bacteria by silanols treatment

    Scientific Electronic Library Online (English)

    Yun-mi, Kim; Samuel, Farrah; Ronald H, Baney.

    2007-04-15

    Full Text Available Antimicrobial action of silanols, a new class of antimicrobials, was investigated by transmission electron microscopy and fluorescent dye studies. Gram-negative bacteria, Escherichia coli and Pseudomonas aeruginosa and Gram-positive bacteria, Staphylococcus aureus and Enterococcus faecalis were trea [...] ted by silanols at concentration of less than 0.2 wt% for one hour. Membrane damage of the bacteria by the silanol treatment was clearly observed by transmission electron microscopy. Separation of the cytoplasmic membrane from the outer membrane for E. coli and disorganized cytoplasmic membrane of the Gram-positive bacteria were observed when compared to the control. Fluorescent dyes, green-fluorescent nucleic acid stain (Syto 9) and the red-fluorescent nucleic acid stain (Propidium iodide), were used to monitor membrane damage of the bacteria by Confocal microscopy and Spectrophotometer. A reduction of the green fluorescent emission was detected for silanol treated bacteria indicating membrane damage of the bacteria and supporting the hypothesis that their viability loss may be due to their membrane damage analogus to alcohols

  3. Aircraft exhaust sulfur emissions

    Energy Technology Data Exchange (ETDEWEB)

    Brown, R.C.; Anderson, M.R.; Miake-Lye, R.C.; Kolb, C.E. [Aerodyne Research, Inc., Billerica, MA (United States). Center for Chemical and Environmental Physics; Sorokin, A.A.; Buriko, Y.I. [Scientific Research Center `Ecolen`, Moscow (Russian Federation)

    1997-12-31

    The extent to which fuel sulfur is converted to SO{sub 3} during combustion and the subsequent turbine flow in supersonic and subsonic aircraft engines is estimated numerically. The analysis is based on: a flamelet model with non-equilibrium sulfur chemistry for the combustor, and a one-dimensional, two-stream model with finite rate chemical kinetics for the turbine. The results indicate that between 2% and 10% of the fuel sulfur is emitted as SO{sub 3}. It is also shown that, for a high fuel sulfur mass loading, conversion in the turbine is limited by the level of atomic oxygen at the combustor exit, leading to higher SO{sub 2} oxidation efficiency at lower fuel sulfur loadings. While SO{sub 2} and SO{sub 3} are the primary oxidation products, the model results further indicate H{sub 2}SO{sub 4} levels on the order of 0.1 ppm for supersonic expansions through a divergent nozzle. This source of fully oxidized S(6) (SO{sub 3} + H{sub 2}SO{sub 4}) exceeds previously calculated S(6) levels due to oxidation of SO{sub 2} by OH in the exhaust plume outside the engine nozzle. (author) 26 refs.

  4. 40 CFR 50.17 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

    Science.gov (United States)

    2010-07-01

    ...standards for sulfur oxides (sulfur dioxide). 50.17 Section 50.17...standards for sulfur oxides (sulfur dioxide). (a) The level of the...measured in the ambient air as sulfur dioxide (SO2 ). (b) The...

  5. 40 CFR 50.4 - National primary ambient air quality standards for sulfur oxides (sulfur dioxide).

    Science.gov (United States)

    2010-07-01

    ...standards for sulfur oxides (sulfur dioxide). 50.4 Section 50.4...standards for sulfur oxides (sulfur dioxide). Link to an amendment published...measured in the ambient air as sulfur dioxide by the reference method...

  6. 40 CFR 50.5 - National secondary ambient air quality standard for sulfur oxides (sulfur dioxide).

    Science.gov (United States)

    2010-07-01

    ...quality standard for sulfur oxides (sulfur dioxide). 50.5 Section 50.5...quality standard for sulfur oxides (sulfur dioxide). (a) The level of...measured in the ambient air as sulfur dioxide by the reference method...

  7. Green tea

    Science.gov (United States)

    ... suggests that taking seven doses of a certain green tea chemical over three days improves some breathing tests in ... However, men who consume high amounts of phytoestrogens, chemicals found in green tea, have a lower risk of developing lung ...

  8. Green skills

    OpenAIRE

    Vona, Francesco; Marin, Giovanni; Consoli, Davide; Popp, David

    2015-01-01

    The catchword ‘green skills’ has been common parlance in policy circles for a while, yet there is little systematic empirical research to guide public intervention for meeting the demand for skills that will be needed to operate and develop green technology. The present paper proposes a data-driven methodology to identify green skills and to gauge the ways in which the demand for these competences responds to environmental regulation. Accordingly, we find that green skills are high-level anal...

  9. Metaphysical green

    DEFF Research Database (Denmark)

    Earon, Ofri

    2011-01-01

    “Sensation of Green is about the mental process like touching, seeing, hearing, or smelling, resulting from the immediate stimulation of landscape forms, plants, trees, wind and water. Sensation of Green triggers a feeling of scale, cheerfulness, calmness and peace. The spatial performance of Sensation of Green is created by a physical interaction between the language of space and the language of nature” The notion of Sensation of Green was developed through a previous study ‘Learning from the S...

  10. Green growth

    OpenAIRE

    Zysman, John; Huberty, Mark; Behrens, Arno; Colijn, Bert; Tol, Richard S.J.; Núñez Ferrer, Jorge.; Aglietta, Michel; Hourcade, Jean-Charles

    2012-01-01

    Green growth is now a central theme of the international climate change negotiations. The Rio+20 Conference in June will concentrate on green growth as one of its main priorities. The Europe 2020 strategy has identified green growth as a fundamental pillar of EU economic policy. This Forum takes stock of the academic discussion and examines the theoretical and empirical underpinning of the concepts of green growth and employment through environmental policy.

  11. Single cell visualization of sulfur cycling in intertidal microbial mats

    Science.gov (United States)

    Dawson, K.; Green, A.; Orphan, V. J.

    2014-12-01

    Chemoautrophic microbial mats form in shallow intertidal pools adjacent to sulfidic hydrothermal vents in San Pedro, CA. Sulfide is primarily geologically derived. However, microscopy revealed deltaproteobacteria closely associated with Beggiatoa -like filaments, indicating an additional biogenic sulfide source, derived from sulfate reduction or sulfur disproportionation. At small scales the intercellular interaction of sulfide producing and sulfide consuming bacteria may play a important role in biogeochemical sulfur cycling. We explored the intracellular transfer of biologically derived sulfide in this system with triple and quadruple stable isotope labeling experiments: 13C, 15N, 33S, and 34S. Silicon wafers colonized by microbial mats in situ, were then incubated with 34SO42- or 34SO42- and 33S0 as well as 13C-acetate and 15NH4+and analyzed by fluorescent in situ hybridization (FISH) coupled to nanometer-scale secondary ion mass spectrometry (NanoSIMS). We observed enrichment of 34S and 33S in both deltaproteobacteria and sulfide oxidizing gammaproteobacteria. Greater enrichment relative to killed controls occurred in deltaproteobacteria than the sulfide oxidizers during both sulfate reducing (?34Sdelta-killed = 240‰, ?34Sgamma-killed = 40‰) and sulfur disproportionating incubations (?33Sdelta-killed = 1730‰, ?33Sgamma-killed = 1050‰). These results provide a direct visualization of interspecies sulfur transfer and indicate that biogenic sulfide derived from either sulfate or intermediate oxidation state sulfur species plays a role in sulfur cycling in this system.

  12. Lunar Sulfur Capture System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Lunar Sulfur Capture System (LSCS) is an innovative method to recover sulfur compounds from lunar soil using sorbents derived primarily from in-situ resources....

  13. Lunar Sulfur Capture System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Lunar Sulfur Capture System (LSCS) is an innovative method to capture greater than 90 percent of sulfur gases evolved during thermal treatment of lunar soils....

  14. Zeolites Remove Sulfur From Fuels

    Science.gov (United States)

    Voecks, Gerald E.; Sharma, Pramod K.

    1991-01-01

    Zeolites remove substantial amounts of sulfur compounds from diesel fuel under relatively mild conditions - atmospheric pressure below 300 degrees C. Extracts up to 60 percent of sulfur content of high-sulfur fuel. Applicable to petroleum refineries, natural-gas processors, electric powerplants, and chemical-processing plants. Method simpler and uses considerably lower pressure than current industrial method, hydro-desulfurization. Yields cleaner emissions from combustion of petroleum fuels, and protects catalysts from poisoning by sulfur.

  15. Accidents with sulfuric acid

    Directory of Open Access Journals (Sweden)

    Rajkovi? Miloš B.

    2006-01-01

    Full Text Available Sulfuric acid is an important industrial and strategic raw material, the production of which is developing on all continents, in many factories in the world and with an annual production of over 160 million tons. On the other hand, the production, transport and usage are very dangerous and demand measures of precaution because the consequences could be catastrophic, and not only at the local level where the accident would happen. Accidents that have been publicly recorded during the last eighteen years (from 1988 till the beginning of 2006 are analyzed in this paper. It is very alarming data that, according to all the recorded accidents, over 1.6 million tons of sulfuric acid were exuded. Although water transport is the safest (only 16.38% of the total amount of accidents in that way 98.88% of the total amount of sulfuric acid was exuded into the environment. Human factor was the common factor in all the accidents, whether there was enough control of the production process, of reservoirs or transportation tanks or the transport was done by inadequate (old tanks, or the accidents arose from human factor (inadequate speed, lock of caution etc. The fact is that huge energy, sacrifice and courage were involved in the recovery from accidents where rescue teams and fire brigades showed great courage to prevent real environmental catastrophes and very often they lost their lives during the events. So, the phrase that sulfuric acid is a real "environmental bomb" has become clearer.

  16. Sulfur Dioxide Pollution Monitor.

    Science.gov (United States)

    National Bureau of Standards (DOC), Washington, DC.

    The sulfur dioxide pollution monitor described in this document is a government-owed invention that is available for licensing. The background of the invention is outlined, and drawings of the monitor together with a detailed description of its function are provided. A sample stream of air, smokestack gas or the like is flowed through a…

  17. Bioleaching of spent hydro-processing catalyst using acidophilic bacteria and its kinetics aspect.

    Science.gov (United States)

    Mishra, Debaraj; Kim, Dong J; Ralph, David E; Ahn, Jong G; Rhee, Young H

    2008-04-15

    Bioleaching of metals from hazardous spent hydro-processing catalysts was attempted in the second stage after growing the bacteria with sulfur in the first stage. The first stage involved transformation of elemental sulfur particles to sulfuric acid through an oxidation process by acidophilic bacteria. In the second stage, the acidic medium was utilized for the leaching process. Nickel, vanadium and molybdenum contained within spent catalyst were leached from the solid materials to liquid medium by the action of sulfuric acid that was produced by acidophilic leaching bacteria. Experiments were conducted varying the reaction time, amount of spent catalysts, amount of elemental sulfur and temperature. At 50 g/L spent catalyst concentration and 20 g/L elemental sulfur, 88.3% Ni, 46.3% Mo, and 94.8% V were recovered after 7 days. Chemical leaching with commercial sulfuric acid of the similar amount that produced by bacteria was compared. Thermodynamic parameters were calculated and the nature of reaction was found to be exothermic. Leaching kinetics of the metals was represented by different reaction kinetic equations, however, only diffusion controlled model showed the best correlation here. During the whole process Mo showed low dissolution because of substantiate precipitation with leach residues as MoO3. Bioleach residues were characterized by EDX and XRD. PMID:17825485

  18. Bioleaching of spent hydro-processing catalyst using acidophilic bacteria and its kinetics aspect

    International Nuclear Information System (INIS)

    Bioleaching of metals from hazardous spent hydro-processing catalysts was attempted in the second stage after growing the bacteria with sulfur in the first stage. The first stage involved transformation of elemental sulfur particles to sulfuric acid through an oxidation process by acidophilic bacteria. In the second stage, the acidic medium was utilized for the leaching process. Nickel, vanadium and molybdenum contained within spent catalyst were leached from the solid materials to liquid medium by the action of sulfuric acid that was produced by acidophilic leaching bacteria. Experiments were conducted varying the reaction time, amount of spent catalysts, amount of elemental sulfur and temperature. At 50 g/L spent catalyst concentration and 20 g/L elemental sulfur, 88.3% Ni, 46.3% Mo, and 94.8% V were recovered after 7 days. Chemical leaching with commercial sulfuric acid of the similar amount that produced by bacteria was compared. Thermodynamic parameters were calculated and the nature of reaction was found to be exothermic. Leaching kinetics of the metals was represented by different reaction kinetic equations, however, only diffusion controlled model showed the best correlation here. During the whole process Mo showed low dissolution because of substantiate precipitation with leach residues as MoO3. Bioleach residues were characterized by EDX and XRD

  19. Growth kinetics of hydrogen sulfide oxidizing bacteria in corroded concrete from sewers

    International Nuclear Information System (INIS)

    Hydrogen sulfide oxidation by microbes present on concrete surfaces of sewer pipes is a key process in sewer corrosion. The growth of aerobic sulfur oxidizing bacteria from corroded concrete surfaces was studied in a batch reactor. Samples of corrosion products, containing sulfur oxidizing bacteria, were suspended in aqueous solution at pH similar to that of corroded concrete. Hydrogen sulfide was supplied to the reactor to provide the source of reduced sulfur. The removal of hydrogen sulfide and oxygen was monitored. The utilization rates of both hydrogen sulfide and oxygen suggested exponential bacterial growth with median growth rates of 1.25 d-1 and 1.33 d-1 as determined from the utilization rates of hydrogen sulfide and oxygen, respectively. Elemental sulfur was found to be the immediate product of the hydrogen sulfide oxidation. When exponential growth had been achieved, the addition of hydrogen sulfide was terminated leading to elemental sulfur oxidation. The ratio of consumed sulfur to consumed oxygen suggested that sulfuric acid was the ultimate oxidation product. To the knowledge of the authors, this is the first study to determine the growth rate of bacteria involved in concrete corrosion with hydrogen sulfide as source of reduced sulfur.

  20. Sulfur recovery - Cenovus, Foster Creek

    Energy Technology Data Exchange (ETDEWEB)

    Allende-Garcia, Roberto [Cenovus (Canada)

    2011-07-01

    Government regulations on sulfur levels in gas have constricted oil and gas industries to develop and implement facilities along their transportation and refining infrastructures capable of recovering sulfur efficiently from circulating gas and oil. This presentation shows the process of sulfur recovery with the issues and possible solutions applied at a Cenovus facility in Foster Creek. Sulfur recovery is made possible by use of scavenger products, which react with existing sulfur. These scavenger chemicals play a crucial role in efficiency and unwanted residual solid deposition in sulfur recovery units. Since January 2010, given a decrease in sulfur recovery efficiency, technical investigations have been conducted simultaneously in-situ and in an Alberta sulfur research facility to determine the most cost effective scavenger materials to use. Reasonable solid deposition is observed when the unit is opened. Future steps in improving sulfur recovery cover the selection of regenerative recovery systems with 90% sulfur removal, independent of sulfur species. Some suitable alternative processes are presented and compared as possible future possibilities.

  1. Biogenesis of iron-sulfur clusters in mammalian cells: new insights and relevance to human disease

    OpenAIRE

    Tracey A. Rouault

    2012-01-01

    Iron-sulfur (Fe-S) clusters are ubiquitous cofactors composed of iron and inorganic sulfur. They are required for the function of proteins involved in a wide range of activities, including electron transport in respiratory chain complexes, regulatory sensing, photosynthesis and DNA repair. The proteins involved in the biogenesis of Fe-S clusters are evolutionarily conserved from bacteria to humans, and many insights into the process of Fe-S cluster biogenesis have come from studies of model o...

  2. Molecular characterization of anaerobic sulfur-oxidizing microbial communities in up-flow anaerobic sludge blanket reactor treating municipal sewage.

    Science.gov (United States)

    Aida, Azrina A; Hatamoto, Masashi; Yamamoto, Masamitsu; Ono, Shinya; Nakamura, Akinobu; Takahashi, Masanobu; Yamaguchi, Takashi

    2014-11-01

    A novel wastewater treatment system consisting of an up-flow anaerobic sludge blanket (UASB) reactor and a down-flow hanging sponge (DHS) reactor with sulfur-redox reaction was developed for treatment of municipal sewage under low-temperature conditions. In the UASB reactor, a novel phenomenon of anaerobic sulfur oxidation occurred in the absence of oxygen, nitrite and nitrate as electron acceptors. The microorganisms involved in anaerobic sulfur oxidation have not been elucidated. Therefore, in this study, we studied the microbial communities existing in the UASB reactor that probably enhanced anaerobic sulfur oxidation. Sludge samples collected from the UASB reactor before and after sulfur oxidation were used for cloning and terminal restriction fragment length polymorphism (T-RFLP) analysis of the 16S rRNA genes of the bacterial and archaeal domains. The microbial community structures of bacteria and archaea indicated that the genus Smithella and uncultured bacteria within the phylum Caldiserica were the dominant bacteria groups. Methanosaeta spp. was the dominant group of the domain archaea. The T-RFLP analysis, which was consistent with the cloning results, also yielded characteristic fingerprints for bacterial communities, whereas the archaeal community structure yielded stable microbial community. From these results, it can be presumed that these major bacteria groups, genus Smithella and uncultured bacteria within the phylum Caldiserica, probably play an important role in sulfur oxidation in UASB reactors. PMID:24930844

  3. Green Jobs

    OpenAIRE

    Deschenes, Olivier

    2013-01-01

    In recent years the prospect of 'green jobs' or 'green growth' policies have become increasingly prominent, proposed to solve both the environmental challenges associated with global climate change and the persistent unemployment problems observed in many industrialized countries. This short article begins by describing the conceptual, definitional, and measurement issues related to green jobs. I then review the existing evidence from the primarily simulation-based studies that attempt to ass...

  4. Green Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Collison, Melanie

    2011-05-15

    Green chemistry is the science of chemistry used in a way that will not use or create hazardous substances. Dr. Rui Resendes is working in this field at GreenCentre Canada, an offshoot of PARTEQ Innovations in Kingston, Ontario. GreenCentre's preliminary findings suggest their licensed product {sup S}witchable Solutions{sup ,} featuring 3 classes of solvents and a surfactant, may be useful in bitumen oil sands extraction.

  5. Green facades:

    OpenAIRE

    van der Winden, J.; Smits, E

    2014-01-01

    This "designers' manual" is made during the TIDO-course AR0533 Innovation & Sustainability. Knowledge of living organisms applied in buildings can prevent crucial designer mistakes. Therefore this manual provides information on vegetated facades. Green facade, vertical green, green wall, vertical gardens, vegetation walls and living walls; these are all different terms used to describe a vegetated facade. To make things clear about the terminology, three main groups of vegetated facades a...

  6. ;Every dogma has its day': a personal look at carbon metabolism in photosynthetic bacteria.

    Science.gov (United States)

    Ormerod, John

    2003-01-01

    Dogmas are unscientific. What is perhaps the greatest biological dogma of all time, the 'unity of biochemistry' is, in the main, still having its day. According to present knowledge, the exceptions to this dogma are mere details when seen in relation to the biosystem as a whole. Nevertheless the exceptions are scientifically interesting and the understanding of them has led to a better comprehension of photosynthesis and ecology. Until the discovery of (14)C, photosynthetic CO(2) fixation was like a slightly opened black box. With (14)C in hand scientists mapped out the path of carbon in green plant photosynthesis in the course of a few years. The impressive reductive pentose phosphate cycle was almost immediately assumed to be universal in autotrophs, including anoxygenic phototrophs, in spite of the odd observation to the contrary. A new dogma was born and held the field for about two decades. Events began to turn when green sulfur bacteria were found to contain ferredoxin-coupled ketoacid-oxidoreductases. This led to the formulation of a novel CO(2)-fixing pathway, the reductive citric acid cycle, but its general acceptance required much work by many investigators. However, the ice had now been broken and after some years a third mechanism of CO(2) fixation was discovered, this time in Chloroflexus,and then a fourth in the same genus. One consequence of these discoveries is that it has become apparent that oxygen is an important factor that determines the kind of CO(2)-fixing mechanism an organism uses. With the prospect of the characterization of hordes of novel bacteria forecast by molecular ecologists we can expect further distinctive CO(2) fixation mechanisms to turn up. PMID:16228573

  7. Microbial stabilization of sulfur-laden sorbents. Technical report, March 1, 1994--May 31, 1994

    Energy Technology Data Exchange (ETDEWEB)

    Miller, K.W.

    1994-09-01

    Clean coal technologies that involve limestone for sulfur capture generate lime/limestone products laden with sulfur at various oxidation states. If sulfur is completely stabilized as sulfate, the spent sorbent is ready for commercial utilization as gypsum. However, the presence of reduced sulfur species requires additional processing. Thermal oxidation of reduced sulfur can result in undesirable release of SO{sub 2}. Microbial oxidation might provide an inexpensive and effective alternative. Sorbents laden with reduced forms of sulfur such as sulfide, sulfite, or various polythionate species serve as growth substrates for sulfur-oxidizing bacteria, which have the potential to convert all sulfur to sulfate. This quarter work continued with the solid phase of a spent slurry from an inhibited scrubber. The material was primarily CaSO{sub 3}{center_dot}1/2H{sub 2}O. The authors did not detect growth of any bacterial strain in salts medium with the solid phase as the source of sulfur. However, unlike strains of Thiobacillus neapolitanus, the isolate TQ, was not inhibited by the solid phase. Evidence suggests that this organism grows slowly on low concentrations of sulfite.

  8. Sulfur activation at Hiroshima

    International Nuclear Information System (INIS)

    After the atomic bomb explosion in Hiroshima, Yamasaki and Sugimoto were able to measure the fast neutron activation of sulfur in the mastic holding insulators on electric poles (Appendix 5-2). Details of the sample collection and measurement procedure have been described by Hamada. The activation reaction 32S(n,p) 32P has a neutron energy threshold of about 2.5 MeV. The 32P decays by beta-particle emission with a half-life of 14.2 days. In 1958, Yamasaki revised his original data by correcting for self-absorption in the samples and by using new half-life data. The revised sulfur activation data were first compared by Kerr to calculated sulfur activation versus ground range using the one-dimensional, isotropic source output provided for Hiroshima by Preeg. A comparison similar to Kerr's of the measured activation data with calculations is shown. The results were discouraging. The transport calculation using the Preeg source is higher than the measured data by over a factor of two close to the hypocenter. Another discouraging aspect is the scatter in the measured sulfur data points. For example, there are points at larger ground ranges that have higher activities than smaller ground ranges. One normally expects the variation to be a rather smooth, nearly exponential decrease with distance. Because the sulfur activation is by high-energy neutrons and because the geometry of the insulators on the electric poles is simple enough to permit accurate calculations, good agreement between calculation and measurement would lend credence to the procedures being used to reassess the doses to the survivors. Fortunately, a number of developments led to better agreement. The Preeg source was an early, one-dimensional model of the Hiroshima bomb. Whalen and his colleagues at LANL made two-dimensional, coupled radiation and hydrodynamic calculations for the Hiroshima bomb that were better suited to its cylindrical symmetry. They provided an energy- and angle-dependent output of neutrons and gamma rays from the Hiroshima weapon that is used as the source term for the calculation of the free-field, air-over-ground, neutron, prompt gamma ray, and secondary radiation fields in the new dosimetry system (chapter 2,3 and 9). Furthermore, since the comparison in 1981, Hamada made additional corrections to the sulfur activation data. These corrections include a more complete analysis of the self-absorption of the samples, an analysis of their purity, revised locations, and an estimate of the uncertainty in the reported activities. The work reported here uses the two-dimensional output calculation of the Hiroshima explosion to calculate the sulfur activation and compares the results with Hamada's revision of the measurements. Because the axis of the bomb was not vertical when it exploded, the sulfur activation is not simply a function of ground range; it is a function of both the range and the azimuthal location of the insulator with respect to the bomb trajectory

  9. Development of Efficient Flowsheet and Transient Modeling for Nuclear Heat Coupled Sulfur Iodine Cyclefor Hydrogen Production

    Energy Technology Data Exchange (ETDEWEB)

    Shripad T. Revankar; Nicholas R. Brown; Cheikhou Kane; Seungmin Oh

    2010-05-01

    The realization of the hydrogen as an energy carrier for future power sources relies on a practical method of producing hydrogen in large scale with no emission of green house gases. Hydrogen is an energy carrier which can be produced by a thermochemical water splitting process. The Sulfur-Iodine (SI) process is an example of a water splitting method using iodine and sulfur as recycling agents.

  10. Isolation and characterization of bacteria on the drainage water from Ratones mine and its behaviour on pyrite

    International Nuclear Information System (INIS)

    This paper describes some of the studies made about iron and sulfur oxidizing bacteria on the drainage water from Ratones mine. Different liquid and solid media were utilized as well as some energy sources, ferrous sulphate, thiosulfate and sulfur. Some experiment were al so realized on museum grade pyrite aimed at determining the possibilities of applying the mentioned bacteria on the leaching of pyrite and subsequently on the leaching of uranium ores. (Author) 27 refs

  11. Green tea

    Science.gov (United States)

    ... genital warts. Do not confuse green tea with oolong tea or black tea. Oolong tea and black tea are made from the same ... effects. Green tea is not fermented at all. Oolong tea is partially fermented, and black tea is fully ...

  12. Green energy

    International Nuclear Information System (INIS)

    The Norwegian Ministry of Petroleum and Energy is considering a compulsory, green certificate market for renewable energy. This market will stimulate the development of renewable energy sources. In some ways, green certificates is subsidising and instigating the development of energy sources that would otherwise be unprofitable. A green certificate proves that a certain quantity of energy, which is usually electricity, has been produced, and that it is based on renewable energy sources. In the EU there are two driving forces behind the concentration on green energy: the liberalization of the European energy market, and EU's quantitative emission restrictions. However, there is a difference of opinion about the usefulness of a green certificate market if the goal is to increase the production of renewable energy

  13. Rethinking the Ancient Sulfur Cycle

    Science.gov (United States)

    Fike, David A.; Bradley, Alexander S.; Rose, Catherine V.

    2015-05-01

    The sulfur biogeochemical cycle integrates the metabolic activity of multiple microbial pathways (e.g., sulfate reduction, disproportionation, and sulfide oxidation) along with abiotic reactions and geological processes that cycle sulfur through various reservoirs. The sulfur cycle impacts the global carbon cycle and climate primarily through the remineralization of organic carbon. Over geological timescales, cycling of sulfur is closely tied to the redox state of Earth's exosphere through the burial of oxidized (sulfate) and reduced (sulfide) sulfur species in marine sediments. Biological sulfur cycling is associated with isotopic fractionations that can be used to trace the fluxes through various metabolic pathways. The resulting isotopic data provide insights into sulfur cycling in both modern and ancient environments via isotopic signatures in sedimentary sulfate and sulfide phases. Here, we review the deep-time δ34S record of marine sulfates and sulfides in light of recent advances in understanding how isotopic signatures are generated by microbial activity, how these signatures are encoded in marine sediments, and how they may be altered following deposition. The resulting picture shows a sulfur cycle intimately coupled to ambient carbon cycling, where sulfur isotopic records preserved in sedimentary rocks are critically dependent on sedimentological and geochemical conditions (e.g., iron availability) during deposition.

  14. Green bonds

    OpenAIRE

    Söderström, Elias; Larsson Regnström, Alfred

    2014-01-01

    The Green Bond market in Sweden is still relatively new and the first companies to issue these new financial products in Sweden were companies on the real estate market. The purpose of this thesis is to examine the characteristic that makes a Green Bond different to other Bonds and to understand why this product is of interest to investors and issuers. Furthermore we try to estimate the future for this financial product. This descriptive study on Green Bonds at the real estate market derives...

  15. Process for removing sulfur from sulfur-containing gases

    International Nuclear Information System (INIS)

    This patent describes a process for reducing the level of sulfur dioxide in a sulfur dioxide- containing gas. It comprises preparing an aqueous slurry comprising a calcium alkali together with a calcium-reactive silica or alumina which are present in amounts sufficient to allow for the formation of a sulfur dioxide-absorbing component which includes a calcium silicate or calcium aluminate; heating the slurry to a temperature between about 120 degrees and 180 degrees C. to facilitate in the formation of the sulfur dioxide-absorbing component; contacting the gas with the slurry in a manner sufficient to allow for the absorption of sulfur dioxide by the absorbing component; and separating the absorbing component in the form of spent solids from the gas

  16. Process for removing sulfur from sulfur-containing gases

    International Nuclear Information System (INIS)

    This patent describes a process for reducing the level of sulfur dioxide in a sulfur dioxide- containing gas. It comprises preparing an aqueous slurry comprising a calcium alkali together with a calcium-reactive silica or alumina, the calcium alkali and calcium-reactive silica or alumina being introduced into the slurry in a form consisting essentially of a high calcium fly ash, which are present in amounts sufficient to allow for the formation of a sulfur dioxide-absorbing component which includes a calcium silicate or calcium aluminate; heating the slurry to a temperature between about 50 degrees and 200 degrees C. for between about 0.1 and about 24 hours to facilitate in the formation of the sulfur dioxide-absorbing component; contacting the gas with the slurry in a manner sufficient to allow for the absorption of sulfur dioxide by the absorbing component; and separating the absorbing component in the form of spent solids from the gas

  17. Emissions of biogenic sulfur gases from a danish estuary

    Science.gov (United States)

    Barker Jørgensen, Bo; Okholm-Hansen, Bolette

    The diurnal variations in sulfur emission were studied at seven sites in a Danish estuary, Norsminde Fjord. The sites comprised grass vegetation, intertidal mud flats, accretions of green algae, an exposed shore and a river outlet. Direct measurements of emission rates from soil and water were done by a dynamic flux chamber technique in connection with gas Chromatographie detection and separation of the cryogenically trapped sulfur gases. Sulfur gas concentrations in air and sea water were measured together with emission rates at 0.5-1 h intervals over 25-40 h periods. DMS was the most important sulfur gas released from grass and algae, while mostly H 2S was released from intertidal mud flats. OCS, CH 3SH and CS 2 were released from most sites at lower rates. Emission of DMS followed the daylight variations, often with a delay towards maximum emission rates in the evening. H 2S was mostly emitted at night or in short outbursts during low tides. Total sulfur emission rates were 1-10?mol Sm -2 d -1. Extreme rates of 335?mol DMSm -2 d -1 were measured over decomposing green algae ( Ulva lactuca). H 2S emission fractions were < 10 -6 to 2.10 -4. H 2S was detected, along with DMS, CH 3SH, OCS and CS 2, in the oxic seawater of the estuary at diurnal mean concentrations of 0.1-6.5nmol S/ol -1. This may indicate a more widespread occurrence of H 2S in shallow, near-shore waters at nanomolar levels.

  18. Emissions of biogenic sulfur gases from a Danish estuary

    Energy Technology Data Exchange (ETDEWEB)

    Joergensen, B.B.; Okholm-Hansen, B.

    1985-01-01

    The diurnal variations in sulfur emission were studied at seven sites in a Danish estuary, Norsminde Fjord. The sites comprised grass vegetation, intertidal mud flats, accretions of green algae, an exposed shore and a river outlet. Direct measurements of emission rates from soil and water were done by a dynamic flux chamber technique in connection with gas chromatographic detection and separation of the cryogenically trapped sulfur gases. Sulfur gas concentrations in air and seawater were measured together with emission rates at 0.5-1 h intervals over 25-40 h periods. DMS was the most important sulfur gas released from grass and algae, while mostly H2S was released from intertidal mud flats. OCS, CH3SH and CS2 were released from most sites at lower rates. Emission of DMS followed the daylight variations, often with a delay towards maximum emission rates in the evening. H2S was mostly emitted at night or in short outburst during low tides. Total sulfur emission rates were 1-10 mol S m S d . Extreme rates of 335 mol DMS m S d were measured over decomposing green algae (Ulva lactuca). H2S emission fractions were < 10 W to 2 x 10 U. H2S was detected, along with DMS, CH3SH, OCS and CS2, in the oxic seawater of the estuary at diurnal mean concentrations of 0.1-6.5 nmol Sl . This may indicate a more widespread occurrence of H2S in shallow, near-shore waters at nanomolar levels.

  19. Green Tea

    Science.gov (United States)

    ... evidence is not definitive, experts suggest that concentrated green tea extracts be taken with food, and that people discontinue use and consult a health care practitioner if they have a liver disorder or ...

  20. Green Roofs

    Energy Technology Data Exchange (ETDEWEB)

    None

    2004-08-01

    A New Technology Demonstration Publication Green roofs can improve the energy performance of federal buildings, help manage stormwater, reduce airborne emissions, and mitigate the effects of urban heat islands.

  1. Green towers and green walls

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, R. [Sharp and Diamond Landscape Architecture and Planning, Vancouver, BC (Canada)

    2006-07-01

    North American cities face many major environmental and health issues such as urban heat island effect, the intensity of storms, microclimate around buildings, imperviousness of sites, poor air quality and increases in respiratory disease. Several new technologies are starting to address global impacts and community level issues as well as the personal health and comfort of building occupants. These include green towers, living walls, vegetated rooftops and ecological site developments. This paper examined these forms of eco-development and presented their benefits. It discussed green walls in Japan; green towers in Malaysia, Singapore and Great Britain; green facades of climbing plants; active living walls in Canada; and passive living walls in France and Canada. It also discussed thermal walls; thematic walls; vertical gardens and structured wildlife habitat. Last, it presented testing, monitoring, research and conclusions. The Centre for the Advancement of Green Roof Technology is setting up a program to test thermal performance, to assess plant survival and to monitor green walls at the British Columbia Institute of Technology in Vancouver, Canada as much of the research out of Japan is only available in Japanese script. It was concluded that green architecture can provide shade, food, rainwater, shelter for wildlife and mimic natural systems. 15 refs.

  2. Centrifugal enrichment of sulfur isotopes

    International Nuclear Information System (INIS)

    This work contains the results of the research for the complete cycle of the centrifuge enrichment process of all sulfur isotopes. As a result of this work there was obtained, and made available (by centrifuge enrichment process), for the first time hundreds of grams of all the isotopes of sulfur to high enrichment. (author)

  3. Green lights

    DEFF Research Database (Denmark)

    Fisker, Peter Kielberg

    2014-01-01

    This study investigates the effect of drought on economic activity globally using remote sensing data. In particular, predicted variation in greenness is correlated with changes in the density of artificial light observed at night on a grid of 0.25 degree latitude-longitude pixels. I define drought as greenness estimated by lagged variation in monthly rainfall and temperature. This definition of drought performs well in identifying self-reported drought events since 2000 compared with measures o...

  4. Efeito de extratos de própolis verde sobre bactérias patogênicas isoladas do leite de vacas com mastite / Effect of green propolis extracts on patogenic bacteria isolated from milk of cows with mastitis

    Scientific Electronic Library Online (English)

    Marcelo Souza, PINTO; José Eurico de, FARIA; Dejair, MESSAGE; Sérvio Túlio Alves, CASSINI; Carmen Silva, PEREIRA; Marilú Martins, GIOSO.

    Full Text Available A sensibilidade, in vitro, de amostras de Staphylococcus aureus, Staphylococcus sp. coagulase negativos, Streptococcus agalactiae e bactérias do grupo dos coliformes, isoladas do leite de vacas com mastite, a diferentes extratos de própolis, na concentração de 100 mg/ml, foi avaliada pela técnica do [...] antibiograma em discos de papel de filtro com sobrecamada de meio de cultura. Os resultados mostraram que o extrato etanólico de própolis comercial, os extratos etanólico e, em menor proporção, o metanólico inibiram o crescimento das amostras de bactérias Gram-positivas, Staphylococcus aureus, Staphylococcus sp. coagulase negativos e Streptococcus agalactiae. Os extratos obtidos através da água, do acetato de etila e do clorofórmio não inibiram nenhuma amostra bacteriana, assim como os veículos etanol e metanol puros utilizados como controle. A bactéria Gram-negativa testada, do tipo coliforme, não apresentou sensibilidade a nenhum dos extratos. Verificaram-se diferenças significativas (p Abstract in english In vitro, the sensitivity to different propolis extracts, at a concentration of 100 mg/ml, of Staphylococcus aureus, Staphylococcus sp. coagulase negative, Streptococcus agalactiae and bacteria of the coliform group, isolated from the milk of cows with mastitis, was evaluated using the technique of [...] an agar disk diffusion with a medium doublelayer. The results showed that the commercial propolis, the ethanolic extract, and, in a minor proportion, the methanolic extract inhibited the growth of the Gram positive bacteria, Staphylococcus aureus, Staphylococcus sp. coagulase negative and Streptococcus agalactiae. The extracts obtained through water, etila acetate and chloroform did not inhibit any bacterial strains, nor did the pure ethanol and methanol vehicles that were utilized as controls. The Gram negative bacterium tested, from the coliform group, did not show sensitivity to any extract. Bacterial strains of the same species collected from different sources presented significant differences in sensitivity to the extracts (p

  5. Sulfur, ultraviolet radiation, and the early evolution of life.

    Science.gov (United States)

    Kasting, J F; Zahnle, K J; Pinto, J P; Young, A T

    1989-01-01

    The present biosphere is shielded from harmful solar near ultraviolet (UV) radiation by atmospheric ozone. We suggest here that elemental sulfur vapor could have played a similar role in an anoxic, ozone-free, primitive atmosphere. Sulfur vapor would have been produced photochemically from volcanogenic SO2 and H2S. It is composed of ring molecules, primarily S8, that absorb strongly throughout the near UV, yet are expected to be relatively stable against photolysis and chemical attack. It is also insoluble in water and would thus have been immune to rainout or surface deposition over the oceans. The concentration of S8 in the primitive atmosphere would have been limited by its saturation vapor pressure, which is a strong function of temperature. Hence, it would have depended on the magnitude of the atmospheric greenhouse effect. Surface temperatures of 45 degrees C or higher, corresponding to carbon dioxide partial pressures exceeding 2 bars, are required to sustain an effective UV screen. Two additional requirements are that the ocean was saturated with sulfite and bisulfite, and that linear S8 chains must tend to reform rings faster than they are destroyed by photolysis. A warm, sulfur-rich, primitive atmosphere is consistent with inferences drawn from molecular phylogeny, which suggest that some of the earliest organisms were thermophilic bacteria that metabolized elemental sulfur. PMID:2685712

  6. Sulfur meter speeds coal blending

    International Nuclear Information System (INIS)

    The sulfur content has become the most important criterion that industry looks at when purchasing coal. The exact amount of sulfur in coal being processed by a preparation plant must be known and, if possible, controlled by blending coal streams of various sulfur contents. Present techniques, however, of measuring the sulfur in coal involve laborious and time-consuming sampling and chemical analysis (12 to 24 hr), and the results usually are not available until the following day. By then, the coal barges or trains are already on the way to their destinations. A new nuclear sulfur meter is expected to overcome these difficulties and help lead to true automation in coal preparation plants. Initially developed by the Bureau of Mines' Morgantown Energy Research Center (MERC) at Morgantown, W. Va., and completed after reorganization of the center by the US Energy Research and Development Administration (ERDA), the meter can scan coal to produce a reading within 2 min to an accuracy of 0.04 percent sulfur. The meter is expected to soon result in an element-ash-moisture-Btu meter that would rapidly detect the sulfur, sodium, potassium, and overall mineral content of the coal, as well as its ash and Btu content

  7. Anaerobic degradation of benzoate by sulfate-reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Silva, S.P.; Adorno, M.A.T.; Moraes, E.M.; Varesche, M.B.A. [Sao Paulo Univ., Sao Carlos, SP (Brazil). Biological Processes Laboratory

    2004-07-01

    Anaerobic processes are an efficient way to degrade aromatic compounds in industrial wastewater, such as phenol, cresol and benzoate. This study characterized the bacteria that degrades benzoate, an anaerobic degradation intermediate of several complex aromatic compounds. In particular, the study assessed the capacity to use benzoate with sulfate reducing bacteria in mesophilic conditions. Biofilm from polyurethane foam matrices of a fixed bed reactor was used as the cellular inoculum to treat industrial wastewater containing organic peroxide. Dilution techniques were used to purify the material and obtain cultures of cocci. The benzoate consumption capacity in sulfidogenic conditions was observed when the purified inoculum was applied to batch reactors with different benzoate/sulfate relations. Results indicate that purification was positive to bacteria that can degrade aromatic compounds. Desulfococcus multivorans bacteria was identified following the physiologic and kinetic experiments. The 0.6 benzoate/sulfate relation was considered ideal for complete consumption of carbon and total use of sulfur. 10 refs., 3 figs.

  8. Metatranscriptomic analysis of sulfur oxidation genes in the endosymbiont of Solemya velum

    Directory of Open Access Journals (Sweden)

    FrankStewart

    2011-06-01

    Full Text Available Thioautotrophic endosymbionts in the Domain Bacteria mediate key sulfur transformations in marine reducing environments. However, the molecular pathways underlying symbiont metabolism and the extent to which these pathways are expressed in situ are poorly characterized for almost all symbioses. This is largely due to the difficulty of culturing symbionts apart from their hosts. Here, we use pyrosequencing of community RNA transcripts (i.e., the metatranscriptome to characterize enzymes of dissimilatory sulfur metabolism in the model symbiosis between the coastal bivalve Solemya velum and its intracellular thioautotrophic symbionts. High-throughput sequencing of total RNA from the symbiont-containing gill of a single host individual generated 1.6 million sequence reads (500 Mbp. Of these, 43,735 matched Bacteria protein-coding genes in BLASTX searches of the NCBI database. The taxonomic identities of the matched genes indicated relatedness to diverse species of sulfur-oxidizing Gammaproteobacteria, including other thioautotrophic symbionts and the purple sulfur bacterium Allochromatium vinosum. Manual querying of these data identified 28 genes from diverse pathways of sulfur energy metabolism, including the dissimilatory sulfite reductase (Dsr pathway for sulfide oxidation to sulfite, the APS pathway for sulfite oxidation, and the Sox pathway for thiosulfate oxidation. In total, reads matching sulfur energy metabolism genes represented 7% of the Bacteria mRNA pool. Together, these data highlight the dominance of thioautotrophy in the context of symbiont community metabolism, identify the likely pathways mediating sulfur oxidation, and illustrate the utility of metatranscriptome sequencing for characterizing community gene transcription of uncultured symbionts.

  9. Green banking

    Directory of Open Access Journals (Sweden)

    Maja Drobnjakovi?

    2013-07-01

    Full Text Available There is an urgent need to march towards “low - carbon economy”. Global challenges of diminishing fossil fuel reserves, climate change, environmental management and finite natural resources serving an expanding world population - these reasons mean that urgent action is required to transition to solutions which minimize environmental impact and are sustainable. We are at the start of the low - carbon revolution and those that have started on their low - carbon journey already are seeing benefits such as new markets and customers, improved economic, social and environmental performance, and reduced bills and risks. Green investment banks offer alternative financial services: green car loans, energy efficiency mortgages, alternative energy venture capital, eco - savings deposits and green credit cards. These items represent innovative financial products.

  10. Method of preparing graphene-sulfur nanocomposites for rechargeable lithium-sulfur battery electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jun; Lemmon, John P; Yang, Zhenguo; Cao, Yuliang; Li, Xiaolin

    2015-04-07

    A method of preparing a graphene-sulfur nanocomposite for a cathode in a rechargeable lithium-sulfur battery comprising thermally expanding graphite oxide to yield graphene layers, mixing the graphene layers with a first solution comprising sulfur and carbon disulfide, evaporating the carbon disulfide to yield a solid nanocomposite, and grinding the solid nanocomposite to yield the graphene-sulfur nanocomposite. Rechargeable-lithium-sulfur batteries having a cathode that includes a graphene-sulfur nanocomposite can exhibit improved characteristics. The graphene-sulfur nanocomposite can be characterized by graphene sheets with particles of sulfur adsorbed to the graphene sheets. The sulfur particles have an average diameter of less than 50 nm.

  11. Green times

    International Nuclear Information System (INIS)

    The authors, founding members of the ''Green Party'' have in mind to make a very personal contribution to a better understanding of the present political situation which, although it seems to have reached a deadlock, still offers positive chances and prospects. New approaches in policy are mentioned which may help to overcome the present state of resignation of many adolescents and adults. Among other things, they describe themselves setting out for new pathways, the ''Greens'' in Parliament, prospect for the future, opportunities of the ecologically oriented economic policy. Finally, they call upon the reader to think and develop further under the motto ''What we all can do''. (HSCH)

  12. Green networking

    CERN Document Server

    Krief, Francine

    2012-01-01

    This book focuses on green networking, which is an important topic for the scientific community composed of engineers, academics, researchers and industrialists working in the networking field. Reducing the environmental impact of the communications infrastructure has become essential with the ever increasing cost of energy and the need for reducing global CO2 emissions to protect our environment.Recent advances and future directions in green networking are presented in this book, including energy efficient networks (wired networks, wireless networks, mobile networks), adaptive networ

  13. DEGRADATION KINETICS OF MONOSACCHARIDES IN HYDROCHLORIC, SULFURIC, AND SULFUROUS ACID

    Directory of Open Access Journals (Sweden)

    Yan Shi,

    2012-07-01

    Full Text Available The degradation kinetics of monosaccharides during sulfurous acid treatment was compared to hydrochloric acid and to sulfuric acid treatments. Reaction conditions corresponded to the range found in previous research to allow for the production of hemicelluloses-derived monosaccharides through hydrolysis of wood. Degradation behavior of monosaccharides during treatment with each acid was expressed by a second-order reaction rate constant with respect to substrate and acid concentrations, and the activation energy and frequency factor were calculated using the Arrhenius equation. Results demonstrated that the second-order reaction rate of a monosaccharide was dependent on the type of acid, indicating that monosaccharides degrade at different rates under different acids, even when the molar concentration of the acid is the same. The degradation of monosaccharides in sulfurous acid was much slower than that in hydrochloric acid and in sulfuric acid. A comparison of two sequential treatments with sulfuric acid, with and without the bisulfite ion, showed that sulfurous acid has a protective effect on the degradation of monosaccharides.

  14. Darwin y las bacterias / Darwin and bacteria

    Scientific Electronic Library Online (English)

    Walter, Ledermann D.

    2009-02-01

    Full Text Available Con motivo de cumplirse 200 años del natalicio de Darwin y 150 desde la publicación de El Origen de las Especies, se revisa su obra buscando alguna mención de las bacterias, a las cuales el gran naturalista parece, o bien no haber conocido, algo muy difícil en un momento en que causaban sensación en [...] el mundo científico, o bien haber ignorado deliberadamente, porque no encontraba para ellas lugar en su teoría de la evolución. Las bacterias, por su parte, afectaron malamente su vida familiar, falleciendo uno de sus hijos de escarlatina y su hija favorita, Arme, de una tuberculosis agravada por el mismo mal que mató a su hermano. El propio Darwin, desde el regreso del Beagle afectado por una enfermedad crónica hasta ahora no dilucidada, podría haber sufrido de la enfermedad de Chagas, cuyo agente etiológico, si bien no es una bacteria, tiene un similar nivel en la escala evolutiva. Abstract in english As in 2009 the scientific world celebrates two hundreds years from the birthday of Charles Darwin and one hundred and fifty from the publication of The Origin of Species, an analysis of his complete work is performed, looking for any mention of bacteria. But it seems that the great naturahst never t [...] ook knowledge about its existence, something rather improbable in a time when the discovery of bacteria shook the medical world, or he deliberately ignored them, not finding a place for such microscopic beings into his theory of evolution. But the bacteria badly affected his familiar life, killing scarlet fever one of his children and worsening to death the evolution of tuberculosis of his favourite Annie. Darwin himself could suffer the sickness of Chagas, whose etiological agent has a similar level to bacteria in the scale of evolution.

  15. Darwin y las bacterias Darwin and bacteria

    Directory of Open Access Journals (Sweden)

    Walter Ledermann D

    2009-02-01

    Full Text Available Con motivo de cumplirse 200 años del natalicio de Darwin y 150 desde la publicación de El Origen de las Especies, se revisa su obra buscando alguna mención de las bacterias, a las cuales el gran naturalista parece, o bien no haber conocido, algo muy difícil en un momento en que causaban sensación en el mundo científico, o bien haber ignorado deliberadamente, porque no encontraba para ellas lugar en su teoría de la evolución. Las bacterias, por su parte, afectaron malamente su vida familiar, falleciendo uno de sus hijos de escarlatina y su hija favorita, Arme, de una tuberculosis agravada por el mismo mal que mató a su hermano. El propio Darwin, desde el regreso del Beagle afectado por una enfermedad crónica hasta ahora no dilucidada, podría haber sufrido de la enfermedad de Chagas, cuyo agente etiológico, si bien no es una bacteria, tiene un similar nivel en la escala evolutiva.As in 2009 the scientific world celebrates two hundreds years from the birthday of Charles Darwin and one hundred and fifty from the publication of The Origin of Species, an analysis of his complete work is performed, looking for any mention of bacteria. But it seems that the great naturahst never took knowledge about its existence, something rather improbable in a time when the discovery of bacteria shook the medical world, or he deliberately ignored them, not finding a place for such microscopic beings into his theory of evolution. But the bacteria badly affected his familiar life, killing scarlet fever one of his children and worsening to death the evolution of tuberculosis of his favourite Annie. Darwin himself could suffer the sickness of Chagas, whose etiological agent has a similar level to bacteria in the scale of evolution.

  16. Graphene-sulfur nanocomposites for rechargeable lithium-sulfur battery electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jun; Lemmon, John P; Yang, Zhenguo; Cao, Yuiliang; Li, Xiaolin

    2014-06-17

    Rechargeable lithium-sulfur batteries having a cathode that includes a graphene-sulfur nanocomposite can exhibit improved characteristics. The graphene-sulfur nanocomposite can be characterized by graphene sheets with particles of sulfur adsorbed to the graphene sheets. The sulfur particles have an average diameter less than 50 nm..

  17. New Fluorescein Precursors for Live Bacteria Detection.

    Science.gov (United States)

    Guilini, Celia; Baehr, Corinne; Schaeffer, Etienne; Gizzi, Patrick; Rufi, Frédéric; Haiech, Jacques; Weiss, Etienne; Bonnet, Dominique; Galzi, Jean-Luc

    2015-09-01

    Swiftness, reliability, and sensitivity of live bacteria detection in drinking water are key issues for human safety. The most widespread used indicator of live bacteria is a caged form of carboxyfluorescein in which 3' and 6' hydroxyl groups are masked as acetate esters (CFDA). This derivatization altogether abolishes fluorescein fluorescence and renders the molecule prone to passive diffusion through bacterial membranes. Once in the cytoplasm, acetate groups from CFDA are removed by bacterial hydrolases and fluorescence develops, rendering live but not dead cells detectable. Yet the reagent, carboxyfluorescein diacetate, still possesses a free carboxyl group whose ionization constant is such that the majority of the probe is charged at physiological pH. This unfavors probe permeation through membranes. Here, we prepare several chemical modifications of the carboxyl moiety of CFDA, in order to neutralize its charge and improve its passive diffusion through membranes. We show that the ethylamido derivative of the 5-carboxyl group from 5-carboxy-fluorescein diacetate or from Oregon green diacetate or from Oregon green diacetoxymethylester are stable molecules in biological media, penetrate into bacterial cells and are metabolized into fluorescent species. Only live bacteria are revealed since bleached samples are not labeled. Other derivatives with modification of the 5-carboxyl group with an ester group or with a thiourea-based moiety were almost inefficient probes. The most interesting probe, triembarine (5-ethylaminocarboxy-oregon green, 3',6'diacetoxymethyl ester) leads to 6-10 times more sensitive detection of bacteria as compared to CFDA. Addition of contrast agents (trypan blue or brilliant blue R) improve the signal-to-noise ratio by quenching extracellular fluorescence while bromophenol blue quenches both intracellular and extracellular fluorescence, allowing standardization of detections. PMID:26260548

  18. Discriminating Bacteria with Optical Sensors Based on Functionalized Nanoporous Xerogels

    Directory of Open Access Journals (Sweden)

    Sabine Crunaire

    2014-06-01

    Full Text Available An innovative and low-cost method is proposed for the detection and discrimination of indole-positive pathogen bacteria. The method allows the non-invasive detection of gaseous indole, released by bacteria, with nanoporous colorimetric sensors. The innovation comes from the use of nanoporous matrices doped with 4-(dimethylamino-cinnamaldehyde, which act as sponges to trap and concentrate the targeted analyte and turn from transparent to dark green, long before the colonies get visible with naked eyes. With such sensors, it was possible to discriminate E. coli from H. alvei, two indole-positive and negative bacteria after seven hours of incubation.

  19. Methanesulfonate (MSA) Catabolic Genes from Marine and Estuarine Bacteria

    OpenAIRE

    Henriques, Ana C.; Marco, Paolo De

    2015-01-01

    Quantitatively, methanesulfonate (MSA) is a very relevant compound in the global biogeochemical sulfur cycle. Its utilization by bacteria as a source of carbon and energy has been described and a specific enzyme, methanesulfonate monooxygenase (MSAMO), has been found to perform the first catabolic step of its oxidation. Other proteins seemingly involved in the import of MSA into bacterial cells have been reported. In this study, we obtained novel sequences of genes msmA and msmE from marine, ...

  20. Not everything green has green

    International Nuclear Information System (INIS)

    Last week (March 2009) Slovak government extended the preferential treatment of renewable energy. Companies that will produce electricity from biomass, water, wind, solar and underground thermal springs, have guaranteed that they will receive a decently paid at least the next 15 years. It promises them a new government bill on the promotion of renewable energy. So far, the State guaranteed the purchase of green power for only one year in advance. And because it is more expensive than electricity from coal or uranium, green investment firms feared. Fifteen guarantees give assurance. The government will guarantee only purchase green electricity, but also biomethane to produce heat. So, who wants an ordinary agrarian biogas from waste and adjust to such a gas. Slovak gas industry will have to buy it into its network. Biomethane is not in domestic terms only on paper.

  1. From green architecture to architectural green

    DEFF Research Database (Denmark)

    Earon, Ofri

    2011-01-01

    The paper investigates the topic of green architecture from an architectural point of view and not an energy point of view. The purpose of the paper is to establish a debate about the architectural language and spatial characteristics of green architecture. In this light, green becomes an adjective that describes the architectural exclusivity of this particular architecture genre. The adjective green expresses architectural qualities differentiating green architecture from none-green architectur...

  2. Buying Green

    Science.gov (United States)

    Layng, T. V. Joe

    2010-01-01

    In "Buying Green," Joe Layng recognizes that, like all choices we make, our decisions as consumers are more likely to be influenced by their short-term consequences for us as individuals (price, quality) than they are by their long-term consequences for society (environmental impact). He believes that the equation can be tilted in favor of greener…

  3. Going Green

    Centers for Disease Control (CDC) Podcasts

    2008-04-18

    This podcast is for a general audience and provides information on how to recycle, re-use, and restore. It also covers the benefits of â??Going Green" on the environment, health, and social interaction.  Created: 4/18/2008 by National Center for Environmental Health (NCEH), ATSDR.   Date Released: 5/8/2008.

  4. Sulfur metabolism in Beggiatoa alba.

    OpenAIRE

    Schmidt, T. M.; Arieli, B.; Cohen, Y.; Padan, E.; Strohl, W R

    1987-01-01

    The metabolism of sulfide, sulfur, and acetate by Beggiatoa alba was investigated under oxic and anoxic conditions. B. alba oxidized acetate to carbon dioxide with the stoichiometric reduction of oxygen to water. In vivo acetate oxidation was suppressed by sulfide and by several classic respiratory inhibitors, including dibromothymoquinone, an inhibitor specific for ubiquinones. B. alba also carried out an oxygen-dependent conversion of sulfide to sulfur, a reaction that was inhibited by seve...

  5. Interspecies communication in bacteria

    OpenAIRE

    Federle, Michael J.; Bonnie L Bassler

    2003-01-01

    Until recently, bacteria were considered to live rather asocial, reclusive lives. New research shows that, in fact, bacteria have elaborate chemical signaling systems that enable them to communicate within and between species. One signal, termed AI-2, appears to be universal and facilitates interspecies communication. Many processes, including virulence factor production, biofilm formation, and motility, are controlled by AI-2. Strategies that interfere with communication in bacteria are bein...

  6. Species Numbers in Bacteria

    OpenAIRE

    Dykhuizen, Daniel

    2005-01-01

    A modified biological species definition (BSD), i.e., that bacteria exchange genes within a species, but not usually between species, is shown to apply to bacteria. The formal definition of bacterial species, which is more conservative than the modified BSD, is framed in terms of DNA hybridization. From this I estimate there are a million species of bacteria in 30 grams of rich forest topsoil and propose that there will be at least a billion species worldwide.

  7. Nitrogen, carbon, and sulfur metabolism in natural Thioploca samples

    DEFF Research Database (Denmark)

    Otte, S.; Kuenen, JG

    1999-01-01

    Filamentous sulfur bacteria of the genus Thioploca occur as dense mats on the continental shelf off the coast of Chile and Peru. Since little is known about their nitrogen, sulfur, and carbon metabolism, this study was undertaken to investigate their (eco)physiology. Thioploca is able to store internally high concentrations of sulfur globules and nitrate. It has been previously hypothesized that these large vacuolated bacteria can oxidize sulfide by reducing their internally stored nitrate. We examined this nitrate reduction by incubation experiments of washed Thioploca sheaths,vith trichomes in combination with (15)N compounds and mass spectrometry and found that these Thioploca samples produce ammonium at a rate of 1 nmol min(-1) mg of protein(-1). Controls showed no significant activity. Sulfate was shown to be the end product of sulfide oxidation and was observed at a rate of 2 to 3 nmol min(-1) mg of protein(-1). The ammonium and sulfate production rates were not influenced by the addition of sulfide, suggesting that sulfide is first oxidized to elemental sulfur, and in a second independent step elemental sulfur is oxidized to sulfate. The average sulfide oxidation rate measured was 5 nmol min(-1) mg of protein(-1) and could be increased to 10.7 nmol min(-1) mg of protein(-1) after the trichomes were starved for 45 h. Incorporation of (14)CO(2) was at a rate of 0.4 to 0.8 nmol min(-1) mg of protein(-1), which is half the rate calculated from sulfide oxidation. [2-(14)C]acetate incorporation was 0.4 nmol min(-1) mg of protein(-1), which is equal to the CO(2) fixation rate, and no (14)CO(2) production was detected. These results suggest that Thioploca species are facultative chemolithoautotrophs capable of mixotrophic growth. Microautoradiography confirmed that Thioploca cells assimilated the majority of the radiocarbon from [2-(14)C]acetate, with only a minor contribution by epibiontic bacteria present in the samples.

  8. Bacteria-Antagonists

    International Science & Technology Center (ISTC)

    Development of Biological Control Agents Through Use of Recombinant Antagonistic Bacteria Possessing Variable Mechanisms of Antagonisms, High Colonizing Capacity and Marker Traits for their Monitoring in Nature

  9. Influence of heterogeneous sulfur atoms on the negative differential resistance effect in polythiophene

    International Nuclear Information System (INIS)

    In this work, we have carried out theoretical investigations aiming to clarify the effects of sulfur heteroatoms on the transport characteristics in polythiophene. Sulfur atoms in polythiophene are demonstrated to influence the structure and transport process by two aspects: the electron hopping between carbon atoms on both sides of the sulfur atom as well as the effective confinement of ? electrons from the sulfur atom. Based on the static Su-Schrieffer-Heeger model and the nonequilibrium Green's function formalism, we simulate the electron transportation in a metal/polythiophene/metal structure. The simulation results show that the electron hopping via sulfur atoms is responsible for the observed negative differential resistance (NDR) behavior in the I-V curves. The NDR disappears if the electron transport channels from carbon to carbon via sulfur atoms are forbidden. The weaker the effective confinement of ? electrons and the electron hopping between carbon atoms on both sides of the sulfur atom are, the higher is the peak-to-valley ratio of the NDR and the wider the voltage range where the current remains at low levels. These results can help in understanding the NDR effect in polythiophene

  10. Viability of bacteria in dental calculus - A microbiological study

    Directory of Open Access Journals (Sweden)

    Moolya Nikesh

    2010-01-01

    Full Text Available Aim: The aim of this study was (1 To investigate the viability of bacteria within supragingival and subgingival calculus, (2 To examine motility of bacteria, and (3 To identify bacterial morphotypes in calculus. Materials and Methods: Supra and subgingival calculus were harvested from 30 subjects having clinical evidence of chronic inflammatory periodontal disease and were divided into two groups . Samples from both groups were immediately transported to the Department of Microbiology for gram staining, acridine orange staining, bacterial culture and to the Department of Oral Pathology for dark field microscopy. Results: Gram staining revealed presence of bacteria within the samples. Dark field microscopic examination revealed presence of filamentous organisms, spirochetes, and motile short bacilli. Acridine orange fluorescent stain showed that the viable bacteria appeared apple green. Bacterial culture revealed presence of a variety of aerobic organisms. Conclusion: From the results, it appeared that viable bacteria were present within calculus especially within internal channels and lacunae.

  11. Formation of elemental sulfur upon radiolysis of aqueous sulfure dioxide solutions

    International Nuclear Information System (INIS)

    During radiation-chemical decomposition of sulfur dioxide in aqueous solutions the yield of elementary sulfur, depending on sulfur dioxide concentration, pH and introduced addition of sulfuric acid, was measured. The curve of sulfur accumulation features the presence of an induction period and a distinctly pronounced maximum. It has been shown experimentally that in the course of sulfur dioxide radiolysis the reactions of reducing particles and products of SO2 reduction play an essential role

  12. Analysis of the sulfur origin and sulfur isotopic compositions of acid rain

    International Nuclear Information System (INIS)

    Acid rain has been one of the most serious environment problems in the world and the study of sulfur isotope can help us find the sulfur source, composition and have important significance for research to harness acid rain. This paper mainly revolves around three aspects to introduce the significance of sulfur isotopic study, they are sulfur isotopes in coals, sulfur isotopic compositions of surface water and sulfur isotopes in wheat. (authors)

  13. Optimizing stratospheric sulfur geoengineering by seasonally changing sulfur injections

    Science.gov (United States)

    Laakso, Anton; Partanen, Antti-Ilari; Kokkola, Harri; Lehtinen, Kari; Korhonen, Hannele

    2015-04-01

    Solar radiation management (SRM) by stratospheric sulfur injection has been shown to have potential in counteracting global warming if reducing of greenhouse gases has not been achieved fast enough and if climate warming will continue. Injecting large amounts of sulfate particles to the stratosphere would increase the reflectivity of the atmosphere and less sunlight would reach the surface. However, the effectivity (per injected sulphur mass unit) of this kind of geoengineering would decrease when amount of injected sulfur is increased. When sulfur concentration increases, stratospheric particles would grow to larger sizes which have larger gravitational settling velocity and which do not reflect radiation as efficiently as smaller particles. In many previous studies, sulfur has been assumed to be injected along the equator where yearly mean solar intensity is the highest and from where sulfur is spread equally to both hemispheres. However, the solar intensity will change locally during the year and sulfate has been assumed to be injected and spread to the hemisphere also during winter time, when the solar intensity is low. Thus sulfate injection could be expected to be more effective, if sulfur injection area is changed seasonally. Here we study effects of the different SRM injection scenarios by using two versions of the MPI climate models. First, aerosol spatial and temporal distributions as well as the resulting radiative properties from the SRM are defined by using the global aerosol-climate model ECHAM6.1-HAM2.2-SALSA. After that, the global and regional climate effects from different injection scenarios are predicted by using the Max Planck Institute's Earth System Model (MPI-ESM). We carried out simulations, where 8 Tg of sulfur is injected as SO2 to the stratosphere at height of 20-22 km in an area ranging over a 20 degree wide latitude band. Results show that changing the sulfur injection area seasonally would lead to similar global mean shortwave radiative forcing (-4.41 W/m2 at top of atmosphere) as if sulfur is injected only to the equator (-4.40 W/m2). However zonal mean distribution would be different and forcing is concentrated relatively more to the midlatitudes and less to the equator. Cooling effect from the geoengineering and warming effect from the increased greenhouse gas has been shown in many studies to lead to cooling in the equator and warming in the poles compared the preindustrial conditions. Changing the injection area seasonally might prevent this from happening and lead globally to more homogeneous temperature change.

  14. Genomic analysis reveals versatile heterotrophic capacity of a potentially symbiotic sulfur-oxidizing bacterium in sponge

    KAUST Repository

    Tian, Renmao

    2014-08-29

    Sulfur-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB) play essential roles in marine sponges. However, the detailed characteristics and physiology of the bacteria are largely unknown. Here, we present and analyse the first genome of sponge-associated SOB using a recently developed metagenomic binning strategy. The loss of transposase and virulence-associated genes and the maintenance of the ancient polyphosphate glucokinase gene suggested a stabilized SOB genome that might have coevolved with the ancient host during establishment of their association. Exclusive distribution in sponge, bacterial detoxification for the host (sulfide oxidation) and the enrichment for symbiotic characteristics (genes-encoding ankyrin) in the SOB genome supported the bacterial role as an intercellular symbiont. Despite possessing complete autotrophic sulfur oxidation pathways, the bacterium developed a much more versatile capacity for carbohydrate uptake and metabolism, in comparison with its closest relatives (Thioalkalivibrio) and to other representative autotrophs from the same order (Chromatiales). The ability to perform both autotrophic and heterotrophic metabolism likely results from the unstable supply of reduced sulfur in the sponge and is considered critical for the sponge-SOB consortium. Our study provides insights into SOB of sponge-specific clade with thioautotrophic and versatile heterotrophic metabolism relevant to its roles in the micro-environment of the sponge body. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  15. Visualizing bacteria in nematodes using fluorescent microscopy.

    Science.gov (United States)

    Murfin, Kristen E; Chaston, John; Goodrich-Blair, Heidi

    2012-01-01

    Symbioses, the living together of two or more organisms, are widespread throughout all kingdoms of life. As two of the most ubiquitous organisms on earth, nematodes and bacteria form a wide array of symbiotic associations that range from beneficial to pathogenic (1-3). One such association is the mutually beneficial relationship between Xenorhabdus bacteria and Steinernema nematodes, which has emerged as a model system of symbiosis (4). Steinernema nematodes are entomopathogenic, using their bacterial symbiont to kill insects (5). For transmission between insect hosts, the bacteria colonize the intestine of the nematode's infective juvenile stage (6-8). Recently, several other nematode species have been shown to utilize bacteria to kill insects (9-13), and investigations have begun examining the interactions between the nematodes and bacteria in these systems (9). We describe a method for visualization of a bacterial symbiont within or on a nematode host, taking advantage of the optical transparency of nematodes when viewed by microscopy. The bacteria are engineered to express a fluorescent protein, allowing their visualization by fluorescence microscopy. Many plasmids are available that carry genes encoding proteins that fluoresce at different wavelengths (i.e. green or red), and conjugation of plasmids from a donor Escherichia coli strain into a recipient bacterial symbiont is successful for a broad range of bacteria. The methods described were developed to investigate the association between Steinernema carpocapsae and Xenorhabdus nematophila (14). Similar methods have been used to investigate other nematode-bacterium associations (9) (,) (15-18)and the approach therefore is generally applicable. The method allows characterization of bacterial presence and localization within nematodes at different stages of development, providing insights into the nature of the association and the process of colonization (14) (,) (16) (,) (19). Microscopic analysis reveals both colonization frequency within a population and localization of bacteria to host tissues (14) (,) (16) (,) (19-21). This is an advantage over other methods of monitoring bacteria within nematode populations, such as sonication (22)or grinding (23), which can provide average levels of colonization, but may not, for example, discriminate populations with a high frequency of low symbiont loads from populations with a low frequency of high symbiont loads. Discriminating the frequency and load of colonizing bacteria can be especially important when screening or characterizing bacterial mutants for colonization phenotypes (21) (,) (24). Indeed, fluorescence microscopy has been used in high throughput screening of bacterial mutants for defects in colonization (17) (,) (18), and is less laborious than other methods, including sonication (22) (,) (25-27)and individual nematode dissection (28) (,) (29). PMID:23117838

  16. Occurrence of Lactic Acid Bacteria During the Different Stages of Vinification and Conservation of Wines

    OpenAIRE

    Lafon-Lafourcade, S.; Carre, E.; Ribéreau-Gayon, P.

    1983-01-01

    We showed that the growth of lactic acid bacteria during alcoholic fermentation depends on the composition of the must. We illustrated how the addition of sulfur dioxide to the must before fermentation and the temperature of storage both affect the growth of these bacteria in the wine. Whereas species of Lactobacillus and Leuconostoc mesenteroides were isolated from grapes and must, Leuconostoc oenos was the only species isolated after alcoholic fermentation. This organism was responsible for...

  17. Green Computing

    Directory of Open Access Journals (Sweden)

    K. Shalini

    2013-01-01

    Full Text Available Green computing is all about using computers in a smarter and eco-friendly way. It is the environmentally responsible use of computers and related resources which includes the implementation of energy-efficient central processing units, servers and peripherals as well as reduced resource consumption and proper disposal of electronic waste .Computers certainly make up a large part of many people lives and traditionally are extremely damaging to the environment. Manufacturers of computer and its parts have been espousing the green cause to help protect environment from computers and electronic waste in any way.Research continues into key areas such as making the use of computers as energy-efficient as Possible, and designing algorithms and systems for efficiency-related computer technologies.

  18. Green WSUS

    OpenAIRE

    Kadry, Seifedine; Joumaa, Chibli

    2012-01-01

    The new era of information and communication technology (ICT) calls for a greater understanding of the environmental impacts of recent technology. With increasing energy cost and growing environmental concerns, green IT is receiving more and more attention. Network and system design play a crucial role in both computing and telecommunication systems. Significant part of this energy cost goes to system update by downloading regularly patches and bug fixes to solve security pr...

  19. Green toxicology.

    Science.gov (United States)

    Maertens, Alexandra; Anastas, Nicholas; Spencer, Pamela J; Stephens, Martin; Goldberg, Alan; Hartung, Thomas

    2014-01-01

    Historically, early identification and characterization of adverse effects of industrial chemicals was difficult because conventional toxicological test methods did not meet R&D needs for rapid, relatively inexpensive methods amenable to small amounts of test material. The pharmaceutical industry now front-loads toxicity testing, using in silico, in vitro, and less demanding animal tests at earlier stages of product development to identify and anticipate undesirable toxicological effects and optimize product development. The Green Chemistry movement embraces similar ideas for development of less toxic products, safer processes, and less waste and exposure. Further, the concept of benign design suggests ways to consider possible toxicities before the actual synthesis and to apply some structure/activity rules (SAR) and in silico methods. This requires not only scientific development but also a change in corporate culture in which synthetic chemists work with toxicologists. An emerging discipline called Green Toxicology (Anastas, 2012) provides a framework for integrating the principles of toxicology into the enterprise of designing safer chemicals, thereby minimizing potential toxicity as early in production as possible. Green Toxicology`s novel utility lies in driving innovation by moving safety considerations to the earliest stage in a chemical`s lifecycle, i.e., to molecular design. In principle, this field is no different than other subdisciplines of toxicology that endeavor to focus on a specific area - for example, clinical, environmental or forensic toxicology. We use the same principles and tools to evaluate an existing substance or to design a new one. The unique emphasis is in using 21st century toxicology tools as a preventative strategy to "design out" undesired human health and environmental effects, thereby increasing the likelihood of launching a successful, sustainable product. Starting with the formation of a steering group and a series of workshops, the Green Toxicology concept is currently spreading internationally and is being refined via an iterative process. PMID:25061898

  20. Green citizenship

    OpenAIRE

    Dean, Hartley

    2001-01-01

    This paper firstly describes the influence that environmentalism and ecologism have had upon thinking about citizenship before secondly, moving on to discuss conventional models of citizenship and potential models of Green citizenship. The discussion focuses on the competing moral discourses that inform our understanding of citizenship and concludes by arguing in favour of an eco-socialist citizenship model that would embrace, on the one hand, an ethic of co-responsibility by which collective...

  1. Green Computing

    OpenAIRE

    Shalini, K; K. Naga Prasanthi

    2013-01-01

    Green computing is all about using computers in a smarter and eco-friendly way. It is the environmentally responsible use of computers and related resources which includes the implementation of energy-efficient central processing units, servers and peripherals as well as reduced resource consumption and proper disposal of electronic waste .Computers certainly make up a large part of many people lives and traditionally are extremely damaging to the environment. Manufacturers of computer a...

  2. Green shopping

    DEFF Research Database (Denmark)

    Thøgersen, John

    2011-01-01

    Findings suggesting that consumers buy “green” products, such as organic foods, for selfish reasons are usually accepted at face value. In this article, the author argues that the evidence backing this claim is questionable and that it reflects post hoc rationalizations and self-presentation biases on behalf of respondents. Knowing that one has incurred substantial personal costs by contributing to a worthy cause can create an uneasiness that one is motivated to relieve, especially when one is u...

  3. Automatically Green

    DEFF Research Database (Denmark)

    Sunstein, Cass R.; Reisch, Lucia

    2014-01-01

    Careful attention to choice architecture promises to open up new possibilities for environmental protection – possibilities that go well beyond, and that may be more effective than, the standard tools of economic incentives, mandates, and bans. How, for example, do consumers choose between environmentally-friendly products or services and alternatives that are potentially damaging to the environment but less expensive? The answer may well depend on the default rule. Indeed, green default rules m...

  4. Automatically Green

    DEFF Research Database (Denmark)

    S. Sunstein, Cass; Reisch, Lucia

    2013-01-01

    Careful attention to choice architecture promises to open up new possibilities for environmental protection – possibilities that go well beyond, and that may be more effective than, the standard tools of economic incentives, mandates, and bans. How, for example, do consumers choose between environmentally-friendly products or services and alternatives that are potentially damaging to the environment but less expensive? The answer may well depend on the default rule. Indeed, green default rules m...

  5. Green Gold

    International Nuclear Information System (INIS)

    The main purpose of this work is to offer a general panoramic of the processes or experiences pilot that are carried out in the Project Green Gold, as strategy of environmental sustainability and organizational invigoration in Choco, especially in the 12 communities of the municipalities of Tado and Condoto. It is also sought to offer a minimum of information on the techniques of handmade production and to show the possibilities to carry out in a rational way the use and use of the natural resources. The Project Green Gold is carried out by the Corporation Green Gold (COV) and co-financed with resources of international and national character, the intervention of the financial resources it achievement mainly for the use of clean processes in the extraction stages and metals benefit. The project is centered primarily in the absence of use of products or toxic substances as the mercury, fair trade, organizational invigoration, execution of 11 approaches and certification of the metals Gold and Platinum. The COV, it has come executing the proposal from the year 2001 with the premise of contributing to the balance between the rational exploitation of the natural resources and the conservation of the environment in the Choco. In the project they are used technical handmade characteristic of the region framed inside the mining activity and production activities are diversified in the productive family units. Those producing with the support of entities of juridical character, specify the necessary game rules for the extraction and products commercialization

  6. ALGAE-BACTERIA INTERACTION IN A LIGHT-DARK CYCLE (JOURNAL VERSION)

    Science.gov (United States)

    Nutrient and population dynamics accompanying algae-bacteria interaction were observed in unialgal, 18-liter batch cultures during a light-dark cycle. The green alga Chlorella vulgaris, and the nitrogen fixing blue-green Anabaena flos-aquae were inoculated with an aquatic communi...

  7. Metal and sulfur composition of iron-molybdenum cofactor of nitrogenase.

    OpenAIRE

    Nelson, M J; Levy, M A; Orme-Johnson, W.H.

    1983-01-01

    The sulfur content of N-methylformamide solutions of cofactor from Clostridium pasteurianum nitrogenase has been determined to be 11.9 (+/- 0.9) mol per mol of molybdenum. This number was determined radiochemically, using iron-molybdenum cofactor isolated from molybdenum-iron protein from bacteria grown on 35SO4. A total of 3.2 (+/- 0.2) mol of sulfur per mol of molybdenum was found to be present in cysteine and methionine, probably arising from contaminating proteins not intrinsic to the cof...

  8. Sulfur-doped graphene derived from cycled lithium-sulfur batteries as a metal-free electrocatalyst for the oxygen reduction reaction.

    Science.gov (United States)

    Ma, Zhaoling; Dou, Shuo; Shen, Anli; Tao, Li; Dai, Liming; Wang, Shuangyin

    2015-02-01

    Heteroatom-doped carbon materials have been extensively investigated as metal-free electrocatalysts to replace commercial Pt/C catalysts in oxygen reduction reactions in fuel cells and Li-air batteries. However, the synthesis of such materials usually involves high temperature or complicated equipment. Graphene-based sulfur composites have been recently developed to prolong the cycling life of Li-S batteries, one of the most attractive energy-storage devices. Given the high cost of graphene, there is significant demand to recycle and reuse graphene from Li-S batteries. Herein, we report a green and cost-effective method to prepare sulfur-doped graphene, achieved by the continuous charge/discharge cycling of graphene-sulfur composites in Li-S batteries. This material was used as a metal-free electrocatalyst for the oxygen reduction reaction and shows better electrocatalytic activity than pristine graphene and better methanol tolerance durability than Pt/C. PMID:25483872

  9. Inactivation of biofilm bacteria.

    OpenAIRE

    LeChevallier, M. W.; Cawthon, C D; Lee, R G

    1988-01-01

    The current project was developed to examine inactivation of biofilm bacteria and to characterize the interaction of biocides with pipe surfaces. Unattached bacteria were quite susceptible to the variety of disinfectants tested. Viable bacterial counts were reduced 99% by exposure to 0.08 mg of hypochlorous acid (pH 7.0) per liter (1 to 2 degrees C) for 1 min. For monochloramine, 94 mg/liter was required to kill 99% of the bacteria within 1 min. These results were consistent with those found ...

  10. Freeze-drying of lactic acid bacteria.

    Science.gov (United States)

    Fonseca, Fernanda; Cenard, Stéphanie; Passot, Stéphanie

    2015-01-01

    Lactic acid bacteria are of great importance for the food and biotechnology industry. They are widely used as starters for manufacturing food (e.g., yogurt, cheese, fermented meats, and vegetables) and probiotic products, as well as for green chemistry applications. Freeze-drying or lyophilization is a convenient method for preservation of bacteria. By reducing water activity to values below 0.2, it allows long-term storage and low-cost distribution at suprazero temperatures, while minimizing losses in viability and functionality. Stabilization of bacteria via freeze-drying starts with the addition of a protectant solution to the bacterial suspension. Freeze-drying includes three steps, namely, (1) freezing of the concentrated and protected cell suspension, (2) primary drying to remove ice by sublimation, and (3) secondary drying to remove unfrozen water by desorption. In this chapter we describe a method for freeze-drying of lactic acid bacteria at a pilot scale, thus allowing control of the process parameters for maximal survival and functionality recovery. PMID:25428024

  11. Biogeochemistry of sulfur and iron in Thioploca-colonized surface sediments in the upwelling area off central Chile

    DEFF Research Database (Denmark)

    Zopfi, Jakob; JØrgensen, Bo Barker

    2007-01-01

    The biogeochemistry of sedimentary sulfur was investigated on the continental shelf off central Chile at water depths between 24 and 88 m under partial influence of an oxygen minimum zone. Dissolved and solid iron and sulfur species, including the sulfur intermediates sulfite, thiosulfate, and elemental sulfur, were analyzed at high resolution in the top 20 cm. All stations were characterized by high rates of sulfate reduction, but only the sediments within the Bay of Concepción contained dissolved sulfide. Due to advection and/or in-situ reoxidation of sulfide, dissolved sulfate was close to bottom water values. Whereas the concentrations of sulfite and thiosulfate were mostly in the submicromolar range, elemental sulfur was by far the dominant sulfur intermediate. Although the large nitrate- and sulfur-storing bacteria Thioploca were abundant, the major part of S0 was located extracellularly. The distribution of sulfur species and dissolved iron suggests the reaction of sulfide with FeOOH as an important pathway for sulfide oxidation and sulfur intermediate formation. This is in agreement with the sulfur isotope composition of co-existing elemental sulfur and iron monosulfides. In the Bay of Concepción, sulfur isotope data suggest that pyrite formation proceeds via the reaction of FeS with polysulfides or H2S. At the shelf stations, on the other hand, pyrite was significantly depleted in 34S relative to its potential precursors FeS and S0. Isotope mass balance considerations suggest further that pyritization at depth includes light sulfide, potentially originating from bacterial sulfur disproportionation. The ?34S-values of pyrite down to -38‰ vs. V-CDT are among the lightest found in organic-rich marine sediments. Seasonal variations in the sulfur isotope composition of dissolved sulfate indicated a dynamic non-steady-state sulfur cycle in the surface sediments. The 18O content of porewater sulfate increased with depth at all sites compared to the bottom water composition due to intracellular isotope exchange reactions during microbial sulfur transformations.

  12. Biogeochemistry of sulfur and iron in Thioploca-colonized surface sediments in the upwelling area off central Chile.

    DEFF Research Database (Denmark)

    Zopfi, Jakob; Michael E., Böttcher

    2008-01-01

    The biogeochemistry of sedimentary sulfur was investigated on the continental shelf off central Chile at water depths between 24 and 88 m under partial influence of an oxygen minimum zone. Dissolved and solid iron and sulfur species, including the sulfur intermediates sulfite, thiosulfate, and elemental sulfur, were analyzed at high resolution in the top 20 cm. All stations were characterized by high rates of sulfate reduction, but only the sediments within the Bay of Concepción contained dissolved sulfide. Due to advection and/or in-situ reoxidation of sulfide, dissolved sulfate was close to bottom water values. Whereas the concentrations of sulfite and thiosulfate were mostly in the submicromolar range, elemental sulfur was by far the dominant sulfur intermediate. Although the large nitrate- and sulfur-storing bacteria Thioploca were abundant, the major part of S0 was located extracellularly. The distribution of sulfur species and dissolved iron suggests the reaction of sulfide with FeOOH as an important pathway for sulfide oxidation and sulfur intermediate formation. This is in agreement with the sulfur isotope composition of co-existing elemental sulfur and iron monosulfides. In the Bay of Concepción, sulfur isotope data suggest that pyrite formation proceeds via the reaction of FeS with polysulfides or H2S. At the shelf stations, on the other hand, pyrite was significantly depleted in 34S relative to its potential precursors FeS and S0. Isotope mass balance considerations suggest further that pyritization at depth includes light sulfide, potentially originating from bacterial sulfur disproportionation. The ?34S-values of pyrite down to -38‰ vs. V-CDT are among the lightest found in organic-rich marine sediments. Seasonal variations in the sulfur isotope composition of dissolved sulfate indicated a dynamic non-steady-state sulfur cycle in the surface sediments. The 18O content of porewater sulfate increased with depth at all sites compared to the bottom water composition due to intracellular isotope exchange reactions during microbial sulfur transformations.

  13. Green shipping management

    CERN Document Server

    Lun, Y H Venus; Wong, Christina W Y; Cheng, T C E

    2016-01-01

    This book presents theory-driven discussion on the link between implementing green shipping practices (GSP) and shipping firm performance. It examines the shipping industry’s challenge of supporting economic growth while enhancing environmental performance. Consisting of nine chapters, the book covers topics such as the conceptualization of green shipping practices (GSPs), measurement scales for evaluating GSP implementation, greening capability, greening and performance relativity (GPR), green management practice, green shipping network, greening capacity, and greening propensity. In view of the increasing quest for environment protection in the shipping sector, this book provides a good reference for firms to understand and evaluate their capability in carrying out green operations on their shipping activities.

  14. [Selective extraction of metals from zinc concentrate by association of chemolithotrophic bacteria].

    Science.gov (United States)

    Vardanian, N S; Vardanian, A K

    2011-01-01

    Ability for selective extraction of copper and zinc from zinc concentrate using association of chemolithotrophic bacteria was investigated. In the presence of bacterial association, the rate of desalinization of zinc, copper, and iron was increased 3-fold, 4-5-fold, and 2-fold, respectively. Zinc, copper, and iron were levigated with the most significant rate. It was revealed that addition of Fe3+ 2 g/l resulted in reduction of iron desalinization and in 3-fold increase of desalinization rate of copper at constant dissolution rate of mineral zinc. It is suggested that the intensification of copper desalinization is connected with the activity of sulfur-oxidizing bacteria able to activate the mineral surface via elimination of passivation layer of elemental sulfur. It was concluded that sulfur-oxidizing bacteria play a significant role in copper desalinization from zinc concentrate. A unique strain of mesophile sulfur-oxidizing bacteria was isolated from desalinization pulp of zinc concentrate; in the perspective, it may serve as efficient candidate for performing of selective extraction of copper from zinc concentrate. PMID:22232898

  15. Antibotulinal efficacy of sulfur dioxide in meat.

    OpenAIRE

    Tompkin, R. B.; Christiansen, L. N.; Shaparis, A B

    1980-01-01

    The addition of sodium metabisulfite as a source of sulfur dioxide delayed botulinal outgrowth in perishable canned comminuted pork when it was temperature abused at 27 degree C. The degree of inhibition was directly related to the level of sulfur dioxide. Levels greater than 100 microgram of sulfur dioxide per g were necessary to achieve significant inhibition when a target level of 100 botulinal spores per g was used. Sodium nitrite partially reduced the efficacy of the sulfur dioxide. Sulf...

  16. Efficient Electrolytes for Lithium–Sulfur Batteries

    OpenAIRE

    Angulakshmi, Natarajan; Stephan, Arul Manuel

    2015-01-01

    This review article mainly encompasses on the state-of-the-art electrolytes for lithium–sulfur batteries. Different strategies have been employed to address the issues of lithium–sulfur batteries across the world. One among them is identification of electrolytes and optimization of their properties for the applications in lithium–sulfur batteries. The electrolytes for lithium–sulfur batteries are broadly classified as (i) non-aqueous liquid electrolytes, (ii) ionic liquids, (iii) solid polyme...

  17. Anaerobic microbial degradation of methylated sulfur compounds

    OpenAIRE

    Maarel, Marc Jos Elise Cornelis van der,

    1996-01-01

    Dimethylsulfide (DMS) is one of the most abundant organic sulfur compounds in the marine environment and is thought to play an important role in the formation of cloud condensation nuclei through its atmospheric oxidation products methanesulfonic acid and sulfuric acid. DMS also forms a crucial link in the global sulfur cycle because it is the main sulfur species that is transported from marine to terrestrial environments. The precursor of DMS in marine environments is the osmolyte dimethylsu...

  18. Gut bacteria and cancer.

    Science.gov (United States)

    Erdman, Susan E; Poutahidis, Theofilos

    2015-08-01

    Microbiota on the mucosal surfaces of the gastrointestinal (GI) tract greatly outnumbers the cells in the human body. Effects of antibiotics indicate that GI tract bacteria may be determining the fate of distal cancers. Recent data implicate dysregulated host responses to enteric bacteria leading to cancers in extra-intestinal sites. Together these findings point to novel anti-cancer strategies aimed at promoting GI tract homeostasis. PMID:26050963

  19. Green urbanity

    Directory of Open Access Journals (Sweden)

    Alenka Fikfak

    2012-01-01

    Full Text Available Tourism and other culture-based types of small business, which are the leitmotif in the planning of the Europark Ruardi, are becoming the guiding motif in the spatial development of urban centres that are influenced by dynamic transformation processes. The system should build upon the exploitation of both local and regional environmental features. This would encourage the quest for special environmental features, with an emphasis on their conservation, i.e. sustainable development, and connections in a wider context.The Europark is seen as a new strategic point of the Zasavje Region (the region of the central Sava Valley, which is linked to other important points in a region relevant for tourism. Due to the "smallness" of the region and/or the proximity of such points, development can be fast and effective. The interaction of different activities in space yields endless opportunities for users, who choose their own goals and priorities in the use of space. Four theme areas of the Europark area planning are envisaged. The organisation of activities is based on the composition of the mosaic field patterns, where green fields intertwine with areas of different, existing and new, urban functions. The fields of urban and recreation programmes are connected with a network of green areas and walking trails, along which theme park settings are arranged.

  20. Green Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Patten, John

    2013-12-31

    Green Manufacturing Initiative (GMI): The initiative provides a conduit between the university and industry to facilitate cooperative research programs of mutual interest to support green (sustainable) goals and efforts. In addition to the operational savings that greener practices can bring, emerging market demands and governmental regulations are making the move to sustainable manufacturing a necessity for success. The funding supports collaborative activities among universities such as the University of Michigan, Michigan State University and Purdue University and among 40 companies to enhance economic and workforce development and provide the potential of technology transfer. WMU participants in the GMI activities included 20 faculty, over 25 students and many staff from across the College of Engineering and Applied Sciences; the College of Arts and Sciences' departments of Chemistry, Physics, Biology and Geology; the College of Business; the Environmental Research Institute; and the Environmental Studies Program. Many outside organizations also contribute to the GMI's success, including Southwest Michigan First; The Right Place of Grand Rapids, MI; Michigan Department of Environmental Quality; the Michigan Department of Energy, Labor and Economic Growth; and the Michigan Manufacturers Technical Center.

  1. Green chemistry

    International Nuclear Information System (INIS)

    The depletion of world fossil fuel reserves and the involvement of greenhouse gases in the global warming has led to change the industrial and energy policies of most developed countries. The goal is now to reserve petroleum to the uses where it cannot be substituted, to implement renewable raw materials obtained from plants cultivation, and to consider the biodegradability of molecules and of manufactured objects by integrating the lifetime concept in their expected cycle of use. The green chemistry includes the design, development and elaboration of chemical products and processes with the aim of reducing or eliminating the use and generation of harmful compounds for the health and the environment, by adapting the present day operation modes of the chemical industry to the larger framework of the sustainable development. In addition to biofuels, this book reviews the applications of green chemistry in the different industrial processes in concern. Part 1 presents the diversity of the molecules coming from renewable carbon, in particular lignocellulose and the biotechnological processes. Part 2 is devoted to materials and treats of the overall available technological solutions. Part 3 focusses on functional molecules and chemical intermediates, in particular in sugar- and fats-chemistry. Part 4 treats of biofuels under the aspects of their production and use in today's technologies. The last part deals with the global approaches at the environmental and agricultural levels. (J.S.)

  2. Green chemistry

    International Nuclear Information System (INIS)

    A grand challenge facing government, industry, and academia in the relationship of our technological society to the environment is reinventing the use of materials. To address this challenge, collaboration from an interdisciplinary group of stakeholders will be necessary. Traditionally, the approach to risk management of materials and chemicals has been through inerventions intended to reduce exposure to materials that are hazardous to health and the environment. In 1990, the Pollution Prevention Act encouraged a new tact-elimination of hazards at the source. An emerging approach to this grand challenge seeks to embed the diverse set of environmental perspectives and interests in the everyday practice of the people most responsible for using and creating new materials--chemists. The approach, which has come to be known as Green Chemistry, intends to eliminate intrinsic hazard itself, rather than focusing on reducing risk by minimizing exposure. This chapter addresses the representation of downstream environmental stakeholder interests in the upstream everyday practice that is reinventing chemistry and its material inputs, products, and waste as described in the '12 Principles of Green Chemistry'

  3. Sulfur cycling in contaminated aquifers: What can we learn from oxygen isotopes in sulfate? (Invited)

    Science.gov (United States)

    Knoeller, K.; Vogt, C.; Hoth, N.

    2009-12-01

    Bacterial reduction of dissolved sulfate (BSR) is a key process determining the natural attenuation in many contaminated aquifers. For example, in groundwater bodies affected by acid mine drainage (AMD) BSR reduces the contaminant load by producing alkalinity and facilitating a sustainable fixation of sulfur in the sediment. In aquifers contaminated with petroleum hydrocarbons sulfate may act as a terminal electron acceptor for the anaerobic oxidation of the organic contaminants to carbon dioxide and water. Due to the isotope selectivity of sulfate reducing bacteria, BSR shows the most pronounced isotope fractionation within the sulfur cycle. While sulfur displays a straightforward kinetic enrichment in the residual sulfate described by the enrichment factor epsilon (?), the mechanism of oxygen isotope fractionation is still being discussed controversially. Nevertheless, it is agreed on that oxygen isotope exchange between ambient water and residual sulfate occurs during BSR in natural environments. With respect to this potential isotope exchange, the fractionation parameter theta (?) is introduced instead of the kinetic enrichment factor epsilon (?). The dual isotope system considering both sulfate-sulfur and sulfate-oxygen isotope fractionation and the respective fractionation parameters ? and ? provides an excellent tool for the recognition and quantification of BSR. Beyond that, the dual isotope approach may help identify and estimate interfering sulfur transformations such as re-oxidation and disproportionation processes which is especially vital for the understanding of the overall natural attenuation potential of the investigated aquifers. We present two examples from different field studies showing the benefits of applying the combination of sulfur and oxygen isotopes in dissolved sulfate to reveal the details of the sulfur cycle. The first case study is concerned with the evaluation of the potential for BSR in an AMD-affected aquifer close to an abandoned lignite mine. Due to the heterogeneous isotopic composition of the sulfate source (oxidation of sedimentary sulfide), sulfur isotopes alone are inappropriate for the recognition of BSR. Only the application of oxygen isotopes in sulfate provides clear evidence for the activity of sulfate reducing bacteria. However, the obtained small ? value indicates a significant influence of sulfide re-oxidation. In the second example we applied the dual isotope system to investigate the relevance of BSR for natural biodegradation in an aquifer contaminated with BTEX. Isotope fractionation parameters were determined in column experiments operated under near in situ conditions. The differences between field derived and experimental fractionation parameters revealed essential information on the occurrence of sulfur transformations competing with the actual biodegradation reactions. Most important of those processes is the re-oxidation of reduced sulfur species consuming electron acceptors that would be relevant for contaminant oxidation.

  4. Evaluation of the Effect of Green Tea Extract on Mouth Bacterial Activity in the Presence of Propylene Glycol

    OpenAIRE

    Abdolhossein Moghbel; Ahmad Farjzadeh; Nasrin Aghel; Homaun Agheli; Nafiseh Raisi

    2012-01-01

    Background: Compounds present in green tea have proved to inhibit the growth and activity of bacteria associated with infections..Objectives: To assess the effects of green tea leaves extract in presence of propylene glycol on the aerobic mouth bacteria load..Materials and Methods: Saliva of 25 volunteer girl students aging 20-25 years were selected and evaluated by a mouthwash sample containing 1% tannin, as the most effective antibacterial complex in green tea. Comparative studies were also...

  5. 46 CFR 153.1046 - Sulfuric acid.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Sulfuric acid. 153.1046 Section 153.1046 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK....1046 Sulfuric acid. No person may liquefy frozen or congealed sulfuric acid other than by external...

  6. 21 CFR 184.1095 - Sulfuric acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sulfuric acid. 184.1095 Section 184.1095 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1095 Sulfuric acid. (a) Sulfuric acid (H2SO4, CAS Reg. No. 7664-93-9),...

  7. 21 CFR 582.1095 - Sulfuric acid.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Sulfuric acid. 582.1095 Section 582.1095 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS....1095 Sulfuric acid. (a) Product. Sulfuric acid. (b) Conditions of use. This substance is...

  8. Recovery of sulfur from native ores

    Energy Technology Data Exchange (ETDEWEB)

    Womack, J.T.; Wiewiorowski, T.K.; Astley, V.C.; Perez, J.W.; Headington, T.A.

    1992-03-17

    This patent describes a process for removing elemental sulfur from ores containing elemental sulfur. It comprises crushing a sulfur-containing ore to a coarse particle size wherein ore particles produced during crushing enable substantially all of the sulfur to be liberated during a heating step and to produce an ore gangue that is substantially not susceptible to flotation: forming an aqueous ore slurry containing about 50-80% by weight of solids from the crushed ore and adjusting the pH to at least a pH of about 8.0; heating the aqueous ore slurry formed in step (b) under elevated pressure to a temperature of about 240{degrees} - 315{degrees} F. for sufficient time to melt and liberate elemental sulfur contained in the ore to produce liberated molten sulfur and ore gangue, wherein the slurry is heated while agitating the slurry at sufficient velocity to substantially maintain the ore, ore gangue and liberated molten sulfur in suspension; cooling the heated slurry sufficiently to resolidify the liberated molten sulfur; conditioning the aqueous slurry of step (d) with a flotation aid; separating the condition aqueous slurry of ore gangue and resolidified sulfur in a flotation unit to produce a sulfur-rich flotation concentrate overstream; and recovering the sulfur-rich flotation concentrate and separating the sulfur therefrom.

  9. Diversity Profile of Microbes Associated with Anaerobic Sulfur Oxidation in an Upflow Anaerobic Sludge Blanket Reactor Treating Municipal Sewage.

    Science.gov (United States)

    Aida, Azrina A; Kuroda, Kyohei; Yamamoto, Masamitsu; Nakamura, Akinobu; Hatamoto, Masashi; Yamaguchi, Takashi

    2015-01-01

    We herein analyzed the diversity of microbes involved in anaerobic sulfur oxidation in an upflow anaerobic sludge blanket (UASB) reactor used for treating municipal sewage under low-temperature conditions. Anaerobic sulfur oxidation occurred in the absence of oxygen, with nitrite and nitrate as electron acceptors; however, reactor performance parameters demonstrated that anaerobic conditions were maintained. In order to gain insights into the underlying basis of anaerobic sulfur oxidation, the microbial diversity that exists in the UASB sludge was analyzed comprehensively to determine their identities and contribution to sulfur oxidation. Sludge samples were collected from the UASB reactor over a period of 2 years and used for bacterial 16S rRNA gene-based terminal restriction fragment length polymorphism (T-RFLP) and next-generation sequencing analyses. T-RFLP and sequencing results both showed that microbial community patterns changed markedly from day 537 onwards. Bacteria belonging to the genus Desulforhabdus within the phylum Proteobacteria and uncultured bacteria within the phylum Fusobacteria were the main groups observed during the period of anaerobic sulfur oxidation. Their abundance correlated with temperature, suggesting that these bacterial groups played roles in anaerobic sulfur oxidation in UASB reactors. PMID:25817585

  10. Sulfur Dioxide and Material Damage

    Science.gov (United States)

    Gillette, Donald G.

    1975-01-01

    This study relates sulfur dioxide levels with material damage in heavily populated or polluted areas. Estimates of loss were determined from increased maintenance and replacement costs. The data indicate a decrease in losses during the past five years probably due to decline in pollution levels established by air quality standards. (MR)

  11. Radiation induced sulfur dioxide removal

    International Nuclear Information System (INIS)

    The biggest source of air pollution is the combustion of fossil fuels, were pollutants such as particulate, sulfur dioxide (SO2), nitrogen oxides (NOx), and volatile organic compounds (VOC) are emitted. Among these pollutants, sulfur dioxide plays the main role in acidification of the environment. The mechanism of sulfur dioxide transformation in the environment is partly photochemical. This is not direct photooxidation, however, but oxidation through formed radicals. Heterogenic reactions play an important role in this transformation as well; therefore, observations from environmental chemistry can be used in air pollution control engineering. One of the most promising technologies for desulfurization of the flue gases (and simultaneous denitrification) is radiation technology with an electron accelerator application. Contrary to the nitrogen oxides (NOx) removal processes, which is based on pure radiation induced reactions, sulfur dioxide removal depends on two pathways: a thermochemical reaction in the presence of ammonia/water vapor and a radiation set of radiochemical reactions. The mechanism of these reactions and the consequent technological parameters of the process are discussed in this paper. The industrial application of this radiation technology is being implemented in an industrial pilot plant operated by INCT at EPS Kaweczyn. A full-scale industrial plant is currently in operation in China, and two others are under development in Japan and Poland. (author)

  12. Phylogenetic analysis on the soil bacteria distributed in karst forest

    Scientific Electronic Library Online (English)

    JunPei, Zhou; Ying, Huang; MingHe, Mo.

    2009-12-01

    Full Text Available Phylogenetic composition of bacterial community in soil of a karst forest was analyzed by culture-independent molecular approach. The bacterial 16S rRNA gene was amplified directly from soil DNA and cloned to generate a library. After screening the clone library by RFLP, 16S rRNA genes of representa [...] tive clones were sequenced and the bacterial community was analyzed phylogenetically. The 16S rRNA gene inserts of 190 clones randomly selected were analyzed by RFLP and generated 126 different RFLP types. After sequencing, 126 non-chimeric sequences were obtained, generating 113 phylotypes. Phylogenetic analysis revealed that the bacteria distributed in soil of the karst forest included the members assigning into Proteobacteria, Acidobacteria, Planctomycetes, Chloroflexi (Green nonsulfur bacteria), Bacteroidetes, Verrucomicrobia, Nitrospirae, Actinobacteria (High G+C Gram-positive bacteria), Firmicutes (Low G+C Gram-positive bacteria) and candidate divisions (including the SPAM and GN08).

  13. Improvement of Energy Capacity with Vitamin?C Treated Dual-Layered Graphene-Sulfur Cathodes in Lithium-Sulfur Batteries.

    Science.gov (United States)

    Kim, Jin Won; Ocon, Joey D; Kim, Ho-Sung; Lee, Jaeyoung

    2015-09-01

    A graphene-based cathode design for lithium-sulfur batteries (LSB) that shows excellent electrochemical performance is proposed. The dual-layered cathode is composed of a sulfur active layer and a polysulfide absorption layer, and both layers are based on vitamin?C treated graphene oxide at various degrees of reduction. By controlling the degree of reduction of graphene, the dual-layered cathode can increase sulfur utilization dramatically owing to the uniform formation of nanosized sulfur particles, the chemical bonding of dissolved polysulfides on the oxygen-rich sulfur active layer, and the physisorption of free polysulfides on the absorption layer. This approach enables a LSB with a high specific capacity of over 600?mAh?gsulfur (-1) after 100?cycles even under a high current rate of 1C (1675?mA?gsulfur (-1) ). An intriguing aspect of our work is the synthesis of a high-performance dual-layered cathode by a green chemistry method, which could be a promising approach to LSBs with high energy and power densities. PMID:25925659

  14. Green business will remain green

    International Nuclear Information System (INIS)

    It all started with two words. Climate change. The carbon dioxide trading scheme, which was the politicians' idea on solving the number one global problem, followed. Four years ago, when the project was begun, there was no data for project initiation. Quotas for polluters mainly from energy production and other energy demanding industries were distributed based on spreadsheets, maximum output and expected future development of economies. Slovak companies have had a chance to profit from these arrangements since 2005. Many of them took advantage of the situation and turned the excessive quotas into an extraordinary profit which often reached hundreds of million Sk. The fact that the price of free quotas offered for sale dropped basically to 0 in 2006 only proved that the initial distribution was too generous. And the market reacted to the first official measurements of emissions. Slovak companies also contributed to this development. However, when planning the maximum emission volumes for 2008-2012 period, in spite of the fact that actual data were available, their expectations were not realistic. A glance at the figures in the proposal of the Ministry of Environment is sufficient to realize that there will be no major change in the future. And so for many Slovak companies business with a green future will remain green for the next five years. The state decided to give to selected companies even more free space as far as emissions are concerned. The most privileged companies can expect quotas increased by tens of percent. (author)

  15. Green Roofs and Green Building Rating Systems

    Directory of Open Access Journals (Sweden)

    Liaw

    2015-01-01

    Full Text Available The environmental benefits for green building from the Leadership in Energy and Environment Design (LEED and Ecology, Energy, Waste, and Health (EEWH rating systems have been extensively investigated; however, the effect of green roofs on the credit-earning mechanisms is relatively unexplored. This study is concerned with the environmental benefits of green roofs with respect to sustainability, stormwater control, energy savings, and water resources. We focused on the relationship between green coverage and the credits of the rating systems, evaluated the credits efficiency, and performed cost analysis. As an example, we used a university building in Keelung, Northern Taiwan. The findings suggest that with EEWH, the proposed green coverage is 50–75%, whereas with LEED, the proposed green coverage is 100%. These findings have implications for the application of green roofs in green building.

  16. Widespread occurrence of bacterial thiol methyltransferases and the biogenic emission of methylated sulfur gases

    Energy Technology Data Exchange (ETDEWEB)

    Drotar, A.; Burton, G.A. Jr.; Tavernier, J.E.; Fall, R.

    1987-07-01

    A majority of heterotrophic bacteria isolated from soil, water, sediment, vegetation, and marine algae cultures methylated sulfide, producing methanethiol. This was demonstrated (i) with intact cells by measuring the emission of methanethiol with a sulfur-selective chemiluminescence detector, and (ii) in cell extracts by detection of sulfide-dependent thiol methyltransferase activity. Extracts of two Pseudomonas isolates were fractionated by gel-filtration and ion-exchange chromatography, and with sulfide as the substrate a single peak of thiol methyltransferase activity was seen in each case. Extracts of several bacterial strains also contained thiol methyltransferase activity with organic thiols as substrates. Thus, S-adenosylmethionine-dependent thiol methyltransferase activities are widespread in bacteria and may contribute to biogenic emissions of methylated sulfur gases and to the production of methyl thioethers.

  17. Central Region Green Infrastructure

    Data.gov (United States)

    Minnesota Department of Natural Resources — This Green Infrastructure data is comprised of 3 similar ecological corridor data layers ? Metro Conservation Corridors, green infrastructure analysis in counties...

  18. The green building envelope: vertical greening:

    OpenAIRE

    Ottelé, M.

    2011-01-01

    Planting on roofs and façades is one of the most innovative and fastest developing fields of green technologies with respect to the built environment and horticulture. This thesis is focused on vertical greening of structures and to the multi-scale benefits of vegetation. Vertical green can improve the environment in urban areas and is becoming a key design consideration in modern building developments. Vertical greening of structures offers large surfaces with vegetation and at the same time...

  19. Green’s Symmetries in Finite Digraphs

    Directory of Open Access Journals (Sweden)

    Allen D. Parks

    2011-08-01

    Full Text Available The semigroup DV of digraphs on a set V of n labeled vertices is defined. It is shown that DV is faithfully represented by the semigroup Bn of n ´ n Boolean matrices and that the Green’s L, R, H, and D equivalence classifications of digraphs in DV follow directly from the Green’s classifications already established for Bn. The new results found from this are: (i L, R, and H equivalent digraphs contain sets of vertices with identical neighborhoods which remain invariant under certain one-sided semigroup multiplications that transform one digraph into another within the same equivalence class, i.e., these digraphs exhibit Green’s isoneighborhood symmetries; and (ii D equivalent digraphs are characterized by isomorphic inclusion lattices that are generated by their out-neighborhoods and which are preserved under certain two-sided semigroup multiplications that transform digraphs within the same D equivalence class, i.e., these digraphs are characterized by Green’s isolattice symmetries. As a simple illustrative example, the Green’s classification of all digraphs on two vertices is presented and the associated Green’s symmetries are identified.

  20. Intracellular metabolite levels shape sulfur isotope fractionation during microbial sulfate respiration

    OpenAIRE

    Wing, Boswell A.; Halevy, Itay

    2014-01-01

    Microbes can discriminate among metabolites that differ only in the stable isotopes of the same element. This stable isotope fractionation responds systematically to environmental variables like extracellular metabolite concentrations and to physiological ones like cell-specific metabolic rates. These observable characteristics define a stable isotope phenotype, as exemplified by the rich database of experimental sulfur isotope fractionations from sulfate-respiring bacteria and archaea. We de...

  1. Microphysical simulations of sulfur burdens from stratospheric sulfur geoengineering

    OpenAIRE

    English, J. M.; Toon, O. B.; M. J. Mills

    2012-01-01

    Recent microphysical studies suggest that geoengineering by continuous stratospheric injection of SO2 gas may be limited by the growth of the aerosols. We study the efficacy of SO2, H2SO4 and aerosol injections on aerosol mass and optical depth using a three-dimensional general circulation model with sulfur chemistry and sectional aerosol microphysics (WACCM/CARMA). We find increasing injection rates o...

  2. Constitutive and Inducible Green Fluorescent Protein Expression in Bartonella henselae

    OpenAIRE

    Lee, Anthea K.; Falkow, Stanley

    1998-01-01

    The green fluorescent protein (GFP) gene was expressed on a plasmid in B. henselae, and GFP-expressing bacteria were visualized by fluorescence microscopy. HEp-2 cells infected with GFP-expressing bacteria were separated from uninfected cells with a fluorescence activated cell sorter. Promoter fusions of B. henselae chromosomal DNA to gfp were examined by flow cytometry, and a B. henselae groEL promoter fusion which induced expression at 37°C was isolated.

  3. Sulfur Nanoparticles Synthesis and Characterization from H2S Gas, Using Novel Biodegradable Iron Chelates in W/O Microemulsion

    Directory of Open Access Journals (Sweden)

    Harle Arti

    2008-01-01

    Full Text Available AbstractSulfur nanoparticles were synthesized from hazardous H2S gas using novel biodegradable iron chelates in w/o microemulsion system. Fe3+–malic acid chelate (0.05 M aqueous solution was studied in w/o microemulsion containing cyclohexane, Triton X-100 andn-hexanol as oil phase, surfactant, co-surfactant, respectively, for catalytic oxidation of H2S gas at ambient conditions of temperature, pressure, and neutral pH. The structural features of sulfur nanoparticles have been characterized by X-ray diffraction (XRD, transmission electron microscope (TEM, energy dispersive spectroscopy (EDS, diffused reflectance infra-red Fourier transform technique, and BET surface area measurements. XRD analysis indicates the presence of ?-sulfur. TEM analysis shows that the morphology of sulfur nanoparticles synthesized in w/o microemulsion system is nearly uniform in size (average particle size 10 nm and narrow particle size distribution (in range of 5–15 nm as compared to that in aqueous surfactant systems. The EDS analysis indicated high purity of sulfur (>99%. Moreover, sulfur nanoparticles synthesized in w/o microemulsion system exhibit higher antimicrobial activity (against bacteria, yeast, and fungi than that of colloidal sulfur.

  4. Ionizing radiation resistant bacteria

    International Nuclear Information System (INIS)

    The living being are not equal face to ionizing radiations. The palm of resistance goes to some bacteria. The champion at any category, the Deinococcus radiodurans, tolerates radiations doses whom one thousandth would kill a man. Two reasons to this fact: after irradiation, the DNA replication is stopped in order that the bacteria can use a repair process called multiple recombination. It cuts intact pieces of a injured chromosome and recombines them with other intact pieces, reconstituting a functional chromosome. It has also an ability to endure the extended action of oxygen, large source of damages for DNA. (N.C.)

  5. Bacterial viability and antibiotic susceptibility testing with SYTOX green nucleic acid stain.

    OpenAIRE

    Roth, B. L.; Poot, M.; Yue, S T; Millard, P J

    1997-01-01

    A fluorescent nucleic acid stain that does not penetrate living cells was used to assess the integrity of the plasma membranes of bacteria. SYTOX Green nucleic acid stain is an unsymmetrical cyanine dye with three positive charges that is completely excluded from live eukaryotic and prokaryotic cells. Binding of SYTOX Green stain to nucleic acids resulted in a > 500-fold enhancement in fluorescence emission (absorption and emission maxima at 502 and 523 nm, respectively), rendering bacteria w...

  6. Sulfur dioxide molecule sensors based on zigzag graphene nanoribbons with and without Cr dopant

    International Nuclear Information System (INIS)

    Structure, electronic, and transport properties of sulfur dioxide (SO2) molecule adsorbed on pure and Cr doped zigzag graphene nanoribbons (ZGNRs) are investigated by means of first principle density functional theory and nonequilibrium Green's function computations. It is found that Cr doped ZGNR is more sensitive to SO2 molecule than pure ZGNR. The pure ZGNRs with and without SO2 molecule show similar I–V curves, but the current of Cr doped ZGNR will significant increase after SO2 molecule adsorption.

  7. Green nanotechnology

    Science.gov (United States)

    Smith, Geoff B.

    2011-10-01

    Nanotechnology, in particular nanophotonics, is proving essential to achieving green outcomes of sustainability and renewable energy at the scales needed. Coatings, composites and polymeric structures used in windows, roof and wall coatings, energy storage, insulation and other components in energy efficient buildings will increasingly involve nanostructure, as will solar cells. Nanostructures have the potential to revolutionize thermoelectric power and may one day provide efficient refrigerant free cooling. Nanomaterials enable optimization of optical, opto-electrical and thermal responses to this urgent task. Optical harmonization of material responses to environmental energy flows involves (i) large changes in spectral response over limited wavelength bands (ii) tailoring to environmental dynamics. The latter includes engineering angle of incidence dependencies and switchable (or chromogenic) responses. Nanomaterials can be made at sufficient scale and low enough cost to be both economic and to have a high impact on a short time scale. Issues to be addressed include human safety and property changes induced during manufacture, handling and outdoor use. Unexpected bonuses have arisen in this work, for example the savings and environmental benefits of cool roofs extend beyond the more obvious benefit of reduced heat flows from the roof into the building.

  8. Glochidioboside Kills Pathogenic Bacteria by Membrane Perturbation.

    Science.gov (United States)

    Lee, Heejeong; Woo, Eun-Rhan; Lee, Dong Gun

    2015-07-01

    The aim of this study was to evaluate the antibacterial effects of glochidioboside and determine its mechanism of action. Glochidioboside has been reported to be isolated from some plants but the underlying biological properties have remained largely obscure until now. To identify the antibacterial activity of all biological properties, pathogenic bacteria susceptibility test was performed, and the result shows that the compound displays remarkable antibacterial activity against antibiotic-resistant bacteria not to mention general pathogen. To demonstrate membrane disruption and depolarization, SYTOX green and bis-(1,3-dibutylbarbituric acid) trimethine oxonol were used with Escherichia coli O157, and indicated that glochidioboside affected cytoplasmic membranes by permeabilization and depolarization, respectively. Calcein efflux was evident in a membrane model that encapsulated fluorescent dye, and supported the hypothesis of a membrane-active mechanism. To confirm the release of intracellular matrix owing to membrane damage, the movements of potassium ion were observed; the results indicated that the cells treated with glochidioboside leaked potassium ion, thus the damage induced by the compounds lead to leaking intracellular components. We propose that glochidioboside kills pathogenic bacteria via perturbation of integrity of the membrane. PMID:25820208

  9. Decoupling the Impacts of Heterotrophy and Autotrophy on Sulfuric Acid Speleogenesis

    Science.gov (United States)

    Jones, A. A.; Bennett, P.

    2013-12-01

    Within caves such as Movile Caves (Romania), the Frasassi Caves (Italy), and Lower Kane Cave (LKC, Wyoming, USA) the combination of abiotic autoxidation and microbiological oxidation of H2S produces SO42- and H+ that promotes limestone dissolution through sulfuric-acid speleogenesis (SAS). Microbial sulfide oxidation by sulfur-oxidizing bacteria (SOB) has been shown recently to be the dominant process leading to speleogenesis in these caves. However, due to the inherently large diversity of microbial communities within these environments, there are a variety of metabolic pathways that can impact limestone dissolution and carbon cycling to varying degrees. In order to investigate these variations we outfitted a continuous flow bioreactor with a Picarro Wavelength-Scanned Cavity Ring Down Spectrometer (WS-CRDS) that continuously monitored and logged 12CO2 and 13CO2 at ppmv sensitivity and isotope ratios at <0.3‰ precision in simulated cave atmospheres. Bioreactors containing Madison Limestone were inoculated with either a monoculture of the mixotrophic sulfur-oxidizing Thiothrix unzii or a mixed environmental (LKC) sulfur-metabolizing community. Ca2+ and pH were also continuously logged in order to quantify the impact of microbial metabolism on limestone dissolution rate. We found an order of magnitude of variability in limestone dissolution rates that were closely tied to microbial metabolism. In monocultures, limestone dissolution was inhibited by excessive reduced sulfur as T. unzii prefers to store sulfur internally as So under these conditions, generating no acidity. The headspace was depleted in 13C when sulfur was being stored as So and enriched in 13C when sulfur was being converted to SO42-. This suggests a preference for a heterotrophy during periods of high sulfur input and autotrophy when sulfur input is low. This was corroborated by an increase in SO42- during low sulfide input and microscope images showed loss of internal sulfur within the filaments during these periods. In both monoculture and LKC environmental cultures, dissolution rates were highest when sulfur-substrate was limited and CO2 was supplied with no organic carbon. Under these conditions ?13C values were as much as 20‰ higher than abiotic conditions and signifies autotrophic carbon fixation which discriminates against 13C. 16S rRNA sequences confirm that autotrophic SOB dominate within this reactor. In contrast, when acetate was supplied with no supplied CO2, ?13C was relatively constant, maintaining values between -31‰ and as low as -37‰. This signifies heterotrophic metabolism where lighter 12C is preferentially consumed resulting in lighter CO2 in the headspace. 16S rRNA sequences confirm that heterotrophic sulfur-reducing bacteria dominate the community within this reactor. When both acetate and CO2 were supplied the heterotrophic behavior appeared to dominate the system which resulted in a significant drop (15‰) in ?13C and a correlative drop in limestone dissolution rate. These results suggest that chemoautotrophy increases the rate of SAS and CO2 flux within the cave environment while heterotrophy leads to slower SAS or even calcite precipitation. Furthermore, changes in carbon substrate (CO2 vs. Acetate) or sulfur substrate concentrations caused an immediate microbial response that could be observed in all measured chemical variables.

  10. Immunity to Intracellular Bacteria.

    OpenAIRE

    Kaufmann, Stefan H. E.; Follows, George A.; Martin E. Munik

    2012-01-01

    Immunity to intracellular bacteria including Mycobacterium tuberculosis. Mycobacterium leprae, and Listeria monocytogenes depends on specific T cells. Evidence to be described suggests that CD4 (alpha/beta)T cells which interact with each other and with macrophages contribute to acquired resistence against as well as pathogenesis of intracellular bacterial infections.

  11. Polymerization of commercial Mexican sulfur

    Scientific Electronic Library Online (English)

    R.W, Gómez; J.L, Pérez M; V, Marquina; R, Ridaura; M.L, Marquina.

    2007-01-01

    Full Text Available Las características físicas del azufre cambian en forma notable cuando su temperatura es de alrededor de 160°C: a) Un cambio de cuatro órdenes de magnitud en la viscosidad laminar, en un intervalo de 25°C. b) Cambios en su densidad y en la velocidad del sonido. c) Su color se hace más oscuro y su ín [...] dice de refracción y permitividad eléctrica, muestran un mínimo, d) Además existe un interés especial en el proceso de polimerización que ocurre en torno a esa temperatura, debido a que el azufre polimerizado puede tener aplicaciones industriales. Estudios realizados en azufre extra puro (99.999 %) han permitido avanzar en el entendimiento de estos fenómenos, pero aún no se tiene una explicación completa de ellos. Las propiedades del azufre cambian mucho por la presencia de impurezas y gases disueltos en él, por lo que, si se quieren utilizar sus características para uso industrial, hay que proceder con azufre comercial y no de gran pureza. En este trabajo se reportan algunos resultados de espectroscopia infrarroja, espectroscopia Raman y difracción de rayos-X obtenidos en experimentos diseñados para obtener la polimerización de azufre mexicano comercial. Abstract in english As it is well known, the physical characteristics of sulfur exhibit a wide range of interesting phenomena around 160°C (1): a) A shear viscosity change of four orders of magnitude over a 25°C interval (2). b) Changes in density and in sound velocity. c) Its color becomes darker and its refractive in [...] dex and dielectric permittivity reach a minimum. d) Of special interest, because of its possible industrial applications, is the polymerization process that occurs at around 160°C. Studies made in ultra pure sulfur (99.999%) have shed some light on this phenomenon, but a coherent picture is still missing. The properties of sulfur are strongly affected by impurities and dissolved gases, so that a great deal of care is necessary when performing these experiments. If the purpose is to take advantages of these properties for industrial applications, one must rule out the use of ultra-pure sulfur and think in terms of a simple process with a commercial substance. In this work we shall report some infrared spectroscopy, Raman spectroscopy and X-ray diffraction results obtained in our attempts at the polymerization of commercial Mexican sulfur.

  12. Sulfur dioxide residue in sulfur-fumigated edible herbs: The fewer, the safer?

    Science.gov (United States)

    Duan, Su-Min; Xu, Jun; Bai, Ying-Jia; Ding, Yan; Kong, Ming; Liu, Huan-Huan; Li, Xiu-Yang; Zhang, Qing-Shan; Chen, Hu-Biao; Liu, Li-Fang; Li, Song-Lin

    2016-02-01

    The residual content of sulfur dioxide is frequently regarded as the exclusive indicator in the safety evaluation of sulfur-fumigated edible herbs. To examine the feasibility of such assessment criteria, here the variations in residual sulfur dioxide content during sulfur-fumigation and the potential mechanisms involved were investigated, using Angelicae Sinensis Radix (ASR) as a model herb. The residual sulfur dioxide content and ten major bioactive components in sulfur-fumigated ASR samples were dynamically examined at 13 successive time points within 72h sulfur-fumigation. The relationship between the content variation tendency of sulfur dioxide and the ten chemicals was discussed. The results suggested that sulfur dioxide-involved chemical transformation of the original components in ASR might cause large consumption of residual sulfur dioxide during sulfur-fumigation. It implies that without considering the induced chemical transformation of bioactive components, the residual sulfur dioxide content alone might be inadequate to comprehensively evaluate the safety of sulfur-fumigated herbs. PMID:26304328

  13. Effect of different sulfur levels from various sources on brassica napus growth and soil sulfur fractions

    International Nuclear Information System (INIS)

    A two year field study was conducted at two different locations in northern rain fed Punjab, Pakistan to assess the effect of different rates of sulfur application from various sources on soil sulfur fractions and growth of Brassica napus. The treatments included three sulfur sources i. e., single super phosphate, ammonium sulfate and gypsum each applied at five different rates (0, 10, 20, 30 and 40 kg S ha/sup -1/ ). Sulfur application had a significant positive effect on the growth and yield parameters of Brassica napus. Among the sulfur sources ammonium sulfate resulted in maximum increase in plant growth and yield parameters, followed by single super phosphate. Sulfur content and uptake by crop plants was significantly higher with ammonium sulfate application as compared to other two sulfur sources. Sulfur application also exerted a significant positive effect on different S fractions in the soils. On an average, 18.0% of the applied sulfur got incorporated into CaCl/sub 2/ extractable sulfur fraction, while 15.6% and 35.5% entered into adsorbed and organic sulfur fractions in the soils, respectively. The value cost ratio increased significantly by sulfur application up to 30 kg ha/sup -1/. Among sulfur sources, ammonium sulfate performed best giving the highest net return. (author)

  14. Oxidative stress enhances the expression of sulfur assimilation genes: preliminary insights on the Enterococcus faecalis iron-sulfur cluster machinery regulation

    Scientific Electronic Library Online (English)

    Gustavo Pelicioli, Riboldi; Christine Garcia, Bierhals; Eduardo Preusser de, Mattos; Ana Paula Guedes, Frazzon; Pedro Alves, d?Azevedo; Jeverson, Frazzon.

    2014-07-01

    Full Text Available The Firmicutes bacteria participate extensively in virulence and pathological processes. Enterococcus faecalis is a commensal microorganism; however, it is also a pathogenic bacterium mainly associated with nosocomial infections in immunocompromised patients. Iron-sulfur [Fe-S] clusters are inorgani [...] c prosthetic groups involved in diverse biological processes, whose in vivo formation requires several specific protein machineries. Escherichia coli is one of the most frequently studied microorganisms regarding [Fe-S] cluster biogenesis and encodes the iron-sulfur cluster and sulfur assimilation systems. In Firmicutes species, a unique operon composed of the sufCDSUB genes is responsible for [Fe-S] cluster biogenesis. The aim of this study was to investigate the potential of the E. faecalis sufCDSUB system in the [Fe-S] cluster assembly using oxidative stress and iron depletion as adverse growth conditions. Quantitative real-time polymerase chain reaction demonstrated, for the first time, that Gram-positive bacteria possess an OxyR component responsive to oxidative stress conditions, as fully described for E. coli models. Likewise, strong expression of the sufCDSUB genes was observed in low concentrations of hydrogen peroxide, indicating that the lowest concentration of oxygen free radicals inside cells, known to be highly damaging to [Fe-S] clusters, is sufficient to trigger the transcriptional machinery for prompt replacement of [Fe-S] clusters.

  15. Radiolysis of Sulfuric Acid, Sulfuric Acid Monohydrate, and Sulfuric Acid Tetrahydrate and Its Relevance to Europa

    Science.gov (United States)

    Loeffler, M. J.; Hudson, R. L.; Moore, M. H.; Carlson, R. W.

    2011-01-01

    We report laboratory studies on the 0.8 MeV proton irradiation of ices composed of sulfuric acid (H2SO4), sulfuric acid monohydrate (H2SO4 H2O), and sulfuric acid tetrahydrate (H2SO4 4H2O) between 10 and 180 K. Using infrared spectroscopy, we identify the main radiation products as H2O, SO2, (S2O3)x, H3O+, HSO4(exp -), and SO4(exp 2-). At high radiation doses, we find that H2SO4 molecules are destroyed completely and that H2SO4 H2O is formed on subsequent warming. This hydrate is significantly more stable to radiolytic destruction than pure H2SO4, falling to an equilibrium relative abundance of 50% of its original value on prolonged irradiation. Unlike either pure H2SO4 or H2SO4 H2O, the loss of H2SO4 4H2O exhibits a strong temperature dependence, as the tetrahydrate is essentially unchanged at the highest irradiation temperatures and completely destroyed at the lowest ones, which we speculate is due to a combination of radiolytic destruction and amorphization. Furthermore, at the lower temperatures it is clear that irradiation causes the tetrahydrate spectrum to transition to one that closely resembles the monohydrate spectrum. Extrapolating our results to Europa s surface, we speculate that the variations in SO2 concentrations observed in the chaotic terrains are a result of radiation processing of lower hydration states of sulfuric acid and that the monohydrate will remain stable on the surface over geological times, while the tetrahydrate will remain stable in the warmer regions but be destroyed in the colder regions, unless it can be reformed by other processes, such as thermal reactions induced by diurnal cycling.

  16. Sulfuric Acid Speleogenesis: Microbial Karst and Microbial Crust

    Science.gov (United States)

    Engel, A. S.; Bennett, P. C.; Stern, L. A.

    2001-12-01

    Sulfuric acid speleogenesis is a fundamental mechanism of karst formation, and is potentially responsible for the formation of some of the most extensive cave systems yet discovered. Speleogenesis occurs from the rapid dissolution of the host limestone by sulfuric acid produced from biotic and abiotic sulfide oxidation, and with the release of carbon dioxide, secondary gypsum crusts form. This crust develops predominately on the cave walls, often preserving original bedding indicators, until it finally collapses under its own weight to expose fresh limestone for dissolution. While this general speleogenetic process can be inferred from secondary residues in some caves, directly observing this process is difficult, and involves entry into an extreme environment with toxic atmospheres and low pH solutions. Kane Cave, Big Horn County, WY, offers the unique opportunity to study microbe-rock interactions directly. Kane Cave presently contains 3 springs that discharge hydrogen sulfide-rich waters, supporting thick subaqueous mats of diverse microbial communities in the stream passage. Condensation droplets and elemental sulfur form on subaerially exposed gypsum surfaces. Droplets have an average pH of 1.7, and are dominated by dissolved sulfate, Ca, Mg, Al, and Si, with minor Sr and Fe, and trace Mn and U. SEM and EDS examination of the crusts reveal the presence of C, O, and S, as well as authigenic, doubly-terminated quartz crystals. An average ? 13C value of -36 ‰ suggests that the crusts are biogenic and are composed of chemoautotrophic microorganisms. Enrichment cultures of biofilms and acid droplets rapidly produce sulfuric acid, demonstrating the dominance of sulfur-oxidizing bacteria. Colonization of gypsum surfaces by acidophilic microorganisms enhances acid dissolution of the limestone, and hence the growth of the cave itself. Limestone dissolution also results in mineralized crusts and biofilms that accumulate insoluble residues, which serve as sources of nutrient Fe, P, and N to the microbes. Other elements, such as Si, increase in concentration in the acid solutions and low-temperature mineral precipitation occurs. >http://www.geo.utexas.edu/chemhydro/Annette/karstgeo.htm

  17. 40 CFR 52.1881 - Control strategy: Sulfur oxides (sulfur dioxide).

    Science.gov (United States)

    2010-07-01

    ...introduced as fresh feed to the cracking unit. For sulfuric acid production units, the nitrogen in the air feed shall not be included... (xiv) Sulfuric acid production unit means...hydrogen sulfide, organic sulfides and...

  18. Spent fuel reprocessing process by selective sulfurization

    International Nuclear Information System (INIS)

    For the recovery of nuclear materials from spent oxide fuel, a novel reprocessing process by selective sulfurization method was examined. This process consists of 1) voloxidation, 2) selective sulfurization and 3) selective dissolution steps. The advantages of the process are, 1) low temperature sulfurization reaction, 2) consumption of reactants only for the sulfurization of fission products, 3) recycle of oxide fuel materials. Sulfurization behavior of uranium oxides and fission products such as rare-earths (Ln2O3), with CS2 was investigated by XRD analysis as well as thermodynamic consideration. The sulfurization behavior of PuO2 was also investigated by using CeO2 as a stand-in of PuO2. The results are summarized as follows; 1) At voloxidation step, UO2 was found to be oxidized to U3O8 by the heat treatment in air at 1273 K, while a part of U3O8 changed to rare-earth doped UO2 solid solution in the pressure of rare-earths. 2) Rare-earth oxides were selectively sulfurized by CS2 at temperatures lower than 775 K, while U3O8 was reduced to UO2 without sulfurization. 3) Cerium oxide CeO2 showed a similar sulfurization behavior to that of UO2 at temperature range from 573 to 773 K. 4) The sulfurized rare-earths selectively dissolved into nitric acid, while UO2 did not. 5) Sulfurization behaviors of other fission products such as cesium, strontium, platinum group were discussed by thermodynamic consideration. 6) From the above results, process for recycling nuclear materials as oxides (UO2 and PuO2) by selective sulfurization was proposed. (author)

  19. SULFUR COMPOUNDS IN PETROLEUM HYDROCARBON STREAMS

    OpenAIRE

    Antoaneta Pavlova; Pavlina Ivanova; Teodora Dimova

    2012-01-01

    Determination of concentrations of sulfur compounds in different petroleum samples is a true analytical challenge. Only analytical procedures based on gas chromatography can meet the sensitivity and accuracy requirements dictated by up-to-date petroleum industry.The objective of this work is to develop the method for the quantifying of sulfur compounds in petroleum hydrocarbon streams. The optimum parameters for the GC-SCD method are found in order to determine of sulfur compounds in petroleu...

  20. Thiophenic Sulfur Compounds Released During Coal Pyrolysis.

    Science.gov (United States)

    Xing, Mengwen; Kong, Jiao; Dong, Jie; Jiao, Haili; Li, Fan

    2013-06-01

    Thiophenic sulfur compounds are released during coal gasification, carbonization, and combustion. Previous studies indicate that thiophenic sulfur compounds degrade very slowly in the environment, and are more carcinogenic than polycyclic aromatic hydrocarbons and nitrogenous compounds. Therefore, it is very important to study the principle of thiophenic sulfur compounds during coal conversion, in order to control their emission and promote clean coal utilization. To realize this goal and understand the formation mechanism of thiophenic sulfur compounds, this study focused on the release behavior of thiophenic sulfur compounds during coal pyrolysis, which is an important phase for all coal thermal conversion processes. The pyrolyzer (CDS-5250) and gas chromatography-mass spectrometry (Focus GC-DSQII) were used to analyze thiophenic sulfur compounds in situ. Several coals with different coal ranks and sulfur contents were chosen as experimental samples, and thiophenic sulfur compounds of the gas produced during pyrolysis under different temperatures and heating rates were investigated. Levels of benzothiophene and dibenzothiophene were obtained during pyrolysis at temperatures ranging from 200°C to 1300°C, and heating rates ranging from 6°C/ms to 14°C/ms and 6°C/s to 14°C/s. Moreover, the relationship between the total amount of benzothiophene and dibenzothiophene released during coal pyrolysis and the organic sulfur content in coal was also discussed. This study is beneficial for understanding the formation and control of thiophenic sulfur compounds, since it provides a series of significant results that show the impact that operation conditions and organic sulfur content in coal have on the amount and species of thiophenic sulfur compounds produced during coal pyrolysis. PMID:23781126

  1. Thiophenic Sulfur Compounds Released During Coal Pyrolysis

    OpenAIRE

    Xing, Mengwen; Kong, Jiao; Dong, Jie; Jiao, Haili; Li, Fan

    2013-01-01

    Thiophenic sulfur compounds are released during coal gasification, carbonization, and combustion. Previous studies indicate that thiophenic sulfur compounds degrade very slowly in the environment, and are more carcinogenic than polycyclic aromatic hydrocarbons and nitrogenous compounds. Therefore, it is very important to study the principle of thiophenic sulfur compounds during coal conversion, in order to control their emission and promote clean coal utilization. To realize this goal and und...

  2. Can bacteria save the planet?

    OpenAIRE

    Hunter, Philip

    2010-01-01

    Bacteria might just hold the key to preserving the environment for our great grandchildren. Philip Hunter explores some of the novel ways in which systems biology and biotechnology are harnessing bacteria to produce renewable energy and clean up pollution.

  3. Interactions between diatoms and bacteria in laboratory biofilm model communities

    OpenAIRE

    Buhmann, Matthias Torben

    2015-01-01

    Sunlit zones of benthic shallow water habitats belong to the most diverse and productive ecosystems on earth. Here, almost all submerged surfaces are covered by photoautotrophic biofilms that form the basis of benthic food-webs. These biofilms consist of microbial communities that are comprised of photoautotrophic microorganisms, such as diatoms, green algae or cyanobacteria, which via photosynthesis provide the energy for associated heterotrophic microorganisms, mostly bacteria. In this clos...

  4. GREEN MARKETING : GREEN ENVIRONMENT - STRATEGIES AND CHALLENGES

    OpenAIRE

    Bhurelal Patidar; Dinesh Kumar Gupta; Prakash Garg

    2014-01-01

    -Green marketing is a phenomenon which has developed particular import in the modern market. This concept has enabled for the re-marketing and packing of existing products which already adhere to such guidelines. Additionally, the development of green marketing has opened the door of opportunity for companies to co-brand their products into separate line, lauding the green-friendliness of some while ignoring that of others. Such marketing techniques as will be explained are as...

  5. Cable Bacteria in Freshwater Sediments

    DEFF Research Database (Denmark)

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus; Lindequist Dittmer, Anders; Bjerg, Jesper Jensen; Trojan, Daniela; Schreiber, Lars; Damgaard, Lars Riis; Schramm, Andreas; Nielsen, Lars Peter

    2015-01-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshw...

  6. Quenching of fluorescence by crystal violet and its use to differentiate between surface-bound and internalized bacteria

    Science.gov (United States)

    Mathew, S.; Lim, Y. C.; Kishen, A.

    2008-06-01

    Phagocytosis is a complex process involving attachment, ingestion and intracellular processing of bacteria by phagocytes. A great difficulty in the evaluation of this process is to differentiate between attachment of the particles to the cell surface and internalization of the particles by the cells. Various techniques have been used to differentiate internalized and surface-attached bacteria in cultured cells, but only a few permit differentiations between surface-bound and internalized bacteria. In this study the quenching of fluorescence by crystal violet on acridine orange stained bacterial biofilm and planktonic bacterial cells is used to differentiate between surface-bound and internalized bacteria within macrophages. Method: One week old Enterococcus faecalis biofilm was grown on perspex and glass substrates in All-Culture medium (nutrient-rich condition) and phosphate buffered saline (nutrient-deprived condition). As model systems, human monocytic (THP-1) and histiocytic (U937) cell lines were used. These cell lines were incubated with the biofilm bacteria for 4 hrs in CO II incubator at 37 °C. The cells and bacteria were stained with acridine orange and quenched with crystal violet to distinguish between surface-bound and internalized bacteria. Results: The presence of green-fluorescing internalized bacteria was detected within the macrophages under the planktonic, nutrient-rich and nutrient-deprived biofilm conditions. All infecting bacteria take up acridine orange and fluoresced green, crystal violet quenched the fluorescence of extra-cellular adhering bacteria so that only fluorescent intracellular bacteria would be visible under fluorescent light microscopy.

  7. Bacterial Disproportionation of Elemental Sulfur Inferred from a Field Study of Stable-Isotope Fractionations between Elemental Sulfur and Pyrite

    Science.gov (United States)

    Hardisty, D.; Pratt, L. M.; Olyphant, G. A.; Bell, J.; Johnson, A.

    2011-12-01

    Elemental sulfur (ES) is a common product of pyrite oxidation during acid mine drainage (AMD), but bacterial disproportionation of ES has not previously been inferred in acidic environments. Pore water profiles were collected seasonally within a coal-mine waste deposit, Minnehaha, in Southwest Indiana that has been abandoned for over 30 years. Geochemical characterization and modeling were used to assess how the interactions between the sulfur and iron cycle are affected by seasonally dynamic hydrologic conditions. Pore waters were collected seasonally and concentrations of Fe-species and sulfur isotopic compositions of sulfate were determined. Additionally, a sediment core was collected and used for sequential extraction and isotopic characterization of solid-phase sulfur species including elemental sulfur (?34Ses), pyrite (?34Spy), acid-volatile sulfides, water-soluble sulfates, and acid-soluble sulfates. The dominant disulfide phase was found to be pyrite through x-ray diffraction of an additional sediment core. Sulfur isotope fractionations between ?34Spy and ?34Ses (?34Ses-py) of up to -33% are inferred to indicate bacterial disproportionation of ES in the presence of a non-limiting sulfide 'scrub' Fe(III). The initial isotopic composition, following formation from pyrite oxidation, is inferred from ?34Spy, found to be ? 8.75% at the study site. Although ES has previously been found to accumulate in acidic Fe(III)-rich pore waters, ES is typically assumed to account for less than 1% of the oxidized sulfur pool and measurements of the ES isotopic composition are often neglected during field studies of acid AMD. The pore waters at Minnehaha were seasonally suboxic with sharp transitions from Fe(III)- to Fe(II)- dominated conditions near the phreatic surface. It is hypothesized that the sulfide product of ES disproportionation, fractionated by up to -8.6%, is immediately re-oxidized to ES near the redox gradient via reaction with Fe(III). Sulfide re-oxidation allows for the accumulation of isotopically light ES that can then become subject to further sulfur disproportionation. A mass-balance model for ES, incorporating seasonally varying rates for pyrite oxidation, ES disproportionation, and ES oxidation, was developed in order to determine the potential and conditions necessary for extensive recycling of ES by disproportionating bacteria to produce ES enriched in 32S compared to the pyrite source. Simulations run for 32 seasonal cycles resulted in a ?34Ses-py of -16.4.% and an ES concentration of 170 ppm, which is consistent with average values obtained from the sediment core. The findings suggest that ES disproportionation is likely an important microbial process in AMD that should be considered at similar mining waste deposits experiencing seasonally varying hydrologic conditions and that ?34Ses-py can be used to estimate multiple cycles of ES disproportionation in oxic settings where the original source of ES is pyrite oxidation.

  8. Isotopically labeled sulfur compounds and synthetic selenium and tellurium analogues to study sulfur metabolism in marine bacteria

    OpenAIRE

    Brock, Nelson L.; Citron, Christian A; Zell, Claudia; Berger, Martine; Wagner-Döbler, Irene; Petersen, Jörn; Brinkhoff, Thorsten; Simon, Meinhard; Dickschat, Jeroen S

    2013-01-01

    Members of the marine Roseobacter clade can degrade dimethylsulfoniopropionate (DMSP) via competing pathways releasing either methanethiol (MeSH) or dimethyl sulfide (DMS). Deuterium-labeled [2H6]DMSP and the synthetic DMSP analogue dimethyltelluriopropionate (DMTeP) were used in feeding experiments with the Roseobacter clade members Phaeobacter gallaeciensis DSM 17395 and Ruegeria pomeroyi DSS-3, and their volatile metabolites were analyzed by closed-loop stripping and solid-phase microextra...

  9. Manufacture of Probiotic Bacteria

    Science.gov (United States)

    Muller, J. A.; Ross, R. P.; Fitzgerald, G. F.; Stanton, C.

    Lactic acid bacteria (LAB) have been used for many years as natural biopreservatives in fermented foods. A small group of LAB are also believed to have beneficial health effects on the host, so called probiotic bacteria. Probiotics have emerged from the niche industry from Asia into European and American markets. Functional foods are one of the fastest growing markets today, with estimated growth to 20 billion dollars worldwide by 2010 (GIA, 2008). The increasing demand for probiotics and the new food markets where probiotics are introduced, challenges the industry to produce high quantities of probiotic cultures in a viable and stable form. Dried concentrated probiotic cultures are the most convenient form for incorporation into functional foods, given the ease of storage, handling and transport, especially for shelf-stable functional products. This chapter will discuss various aspects of the challenges associated with the manufacturing of probiotic cultures.

  10. Exopolysaccharides from marine bacteria

    Science.gov (United States)

    Chi, Zhenming; Fang, Yan

    2005-01-01

    Microbial polysaccharides represent a class of important products of growing interest for many sectors of industry. In recent years, there has been a growing interest in isolating new exopolysaccharides (EPSs)-producing bacteria from marine environments, particularly from various extreme marine environments. Many new marine microbial EPSs with novel chemical compositions, properties and structures have been found to have potential applications in fields such as adhesives, textiles, Pharmaceuticals and medicine for anti-cancer, food additives, oil recovery and metal removal in mining and industrial waste treatments, etc This paper gives a brief summary of the information about the EPSs produced by marine bacteria, including their chemical compositions, properties and structures, together with their potential applications in industry.

  11. Extracellular communication in bacteria

    DEFF Research Database (Denmark)

    Chhabra, S.R.; Philipp, B.; Eberl, L.; Givskov, Michael Christian; Williams, P.; Camara, M.

    2005-01-01

    Populations of bacterial cells often coordinate their responses to changes in their local environmental conditions through "quorum sensing", a cell-to-cell communication system employing small diffusible signal molecules. While there is considerable diversity in the chemistry of such signal molecules, in different Gram-positive and Gram-negative bacteria they control pathogenicity, secondary metabolite production, biofilm differentiation, DNA transfer and bioluminescence. The development of bios...

  12. Synbiobacther : engineering ???therapeutic??? bacteria

    OpenAIRE

    Rodrigues, L. R.; Rodrigues, Joana L??cia; Machado, C. D.; Kluskens, Leon; M. Mota; Rocha, I.; Ferreira, E.C.

    2012-01-01

    SYNBIOBACTHER ??? Engineering ???therapeutic??? bacteria Rodrigues LR, Rodrigues JL, Machado CD, Kluskens L, Mota M, Rocha I, Ferreira EC IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal Statistics show that over 1.3 million persons will be diagnosed with breast cancer worldwide this year, hence this is an enormously important health risk, and progress leading to enhanced survival...

  13. Blue-green algae

    Science.gov (United States)

    ... liver poisons (microcystins) produced by certain bacteria, and heavy metals. Choose only products that have been tested and ... contaminants, such as liver-damaging substances called microcystins, toxic metals, and harmful bacteria, are POSSIBLY SAFE for most ...

  14. Titanospirillum velox: a huge, speedy, sulfur-storing spirillum from Ebro Delta microbial mats

    Science.gov (United States)

    Guerrero, R.; Haselton, A.; Sole, M.; Wier, A.; Margulis, L.

    1999-01-01

    A long (20-30 micrometer), wide (3-5 micrometer) microbial-mat bacterium from the Ebro Delta (Tarragona, Spain) was grown in mixed culture and videographed live. Intracellular elemental sulfur globules and unique cell termini were observed in scanning-electron-microprobe and transmission-electron micrographs. A polar organelle underlies bundles of greater than 60 flagella at each indented terminus. These Gram-negative bacteria bend, flex, and swim in a spiral fashion; they translate at speeds greater than 10 body lengths per second. The large size of the spirillum permits direct observation of cell motility in single individual bacteria. After desiccation (i.e., absence of standing water for at least 24 h), large populations developed in mat samples remoistened with sea water. Ultrastructural observations reveal abundant large sulfur globules irregularly distributed in the cytoplasm. A multilayered cell wall, pliable and elastic yet rigid, distends around the sulfur globules. Details of the wall, multiflagellated termini, and large cytoplasmic sulfur globules indicate that these fast-moving spirilla are distinctive enough to warrant a genus and species designation: Titanospirillum velox genus nov., sp. nov. The same collection techniques at a similar habitat in the United States (Plum Island, northeast Essex County, Massachusetts) also yielded large populations of the bacterium among purple phototrophic and other inhabitants of sulfurous microbial-mat muds. The months-long survival of T. velox from Spain and from the United States in closed jars filled with mud taken from both localities leads us to infer that this large spirillum has a cosmopolitan distribution.

  15. Graphene-wrapped sulfur nanospheres with ultra-high sulfur loading for high energy density lithium-sulfur batteries

    Science.gov (United States)

    Liu, Ya; Guo, Jinxin; Zhang, Jun; Su, Qingmei; Du, Gaohui

    2015-01-01

    Lithium-sulfur (Li-S) battery with high theoretical energy density is one of the most promising energy storage systems for electric vehicles and intermittent renewable energy. However, due to the poor conductivity of the active material, considerable weight of the electrode is occupied by the conductive additives. Here we report a graphene-wrapped sulfur nanospheres composite (S-nanosphere@G) with sulfur content up to 91 wt% as the high energy density cathode material for Li-S battery. The sulfur nanospheres with diameter of 400-500 nm are synthesized through a solution-based approach with the existence of polyvinylpyrrolidone (PVP). Then the sulfur nanospheres are uniformly wrapped by conductive graphene sheets through the electrostatic interaction between graphene oxide and PVP, followed by reducing of graphene oxide with hydrazine. The design of graphene wrapped sulfur nanoarchitecture provides flexible conductive graphene coating with void space to accommodate the volume expansion of sulfur and to minimize polysulfide dissolution. As a result, the S-nanosphere@G nanocomposite with 91 wt% sulfur shows a reversible initial capacity of 970 mA h g-1 and an average columbic efficiency > 96% over 100 cycles at a rate of 0.2 C. Taking the total mass of electrode into account, the S-nanosphere@G composite is a promising cathode material for high energy density Li-S batteries.

  16. 40 CFR 52.795 - Control strategy: Sulfur dioxide.

    Science.gov (United States)

    2010-07-01

    ...2010-07-01 false Control strategy: Sulfur dioxide. 52.795 Section 52.795...52.795 Control strategy: Sulfur dioxide. (a) Revised APC-13...Pollution Control regulations (sulfur dioxide emission limitation) is...

  17. 40 CFR 180.444 - Sulfur dioxide; tolerances for residues.

    Science.gov (United States)

    2010-07-01

    ...2010-07-01 2010-07-01 false Sulfur dioxide; tolerances for residues. ...Specific Tolerances § 180.444 Sulfur dioxide; tolerances for residues. ...sulfite residues of the fungicide sulfur dioxide (determined as (SO2 ))...

  18. 40 CFR 52.2575 - Control strategy: Sulfur dioxide.

    Science.gov (United States)

    2010-07-01

    ...2010-07-01 false Control strategy: Sulfur dioxide. 52.2575 Section 52.2575...52.2575 Control strategy: Sulfur dioxide. (a) Part D—Approval...Administrator approved the Wisconsin sulfur dioxide control plan. (1) Part...

  19. 40 CFR 52.724 - Control strategy: Sulfur dioxide.

    Science.gov (United States)

    2010-07-01

    ...2010-07-01 false Control strategy: Sulfur dioxide. 52.724 Section 52.724...52.724 Control strategy: Sulfur dioxide. (a) Part D—Conditional...attainment and maintenance of the sulfur dioxide standard, and the...

  20. Pepsin homologues in bacteria

    Directory of Open Access Journals (Sweden)

    Bateman Alex

    2009-09-01

    Full Text Available Abstract Background Peptidase family A1, to which pepsin belongs, had been assumed to be restricted to eukaryotes. The tertiary structure of pepsin shows two lobes with similar folds and it has been suggested that the gene has arisen from an ancient duplication and fusion event. The only sequence similarity between the lobes is restricted to the motif around the active site aspartate and a hydrophobic-hydrophobic-Gly motif. Together, these contribute to an essential structural feature known as a psi-loop. There is one such psi-loop in each lobe, and so each lobe presents an active Asp. The human immunodeficiency virus peptidase, retropepsin, from peptidase family A2 also has a similar fold but consists of one lobe only and has to dimerize to be active. All known members of family A1 show the bilobed structure, but it is unclear if the ancestor of family A1 was similar to an A2 peptidase, or if the ancestral retropepsin was derived from a half-pepsin gene. The presence of a pepsin homologue in a prokaryote might give insights into the evolution of the pepsin family. Results Homologues of the aspartic peptidase pepsin have been found in the completed genomic sequences from seven species of bacteria. The bacterial homologues, unlike those from eukaryotes, do not possess signal peptides, and would therefore be intracellular acting at neutral pH. The bacterial homologues have Thr218 replaced by Asp, a change which in renin has been shown to confer activity at neutral pH. No pepsin homologues could be detected in any archaean genome. Conclusion The peptidase family A1 is found in some species of bacteria as well as eukaryotes. The bacterial homologues fall into two groups, one from oceanic bacteria and one from plant symbionts. The bacterial homologues are all predicted to be intracellular proteins, unlike the eukaryotic enzymes. The bacterial homologues are bilobed like pepsin, implying that if no horizontal gene transfer has occurred the duplication and fusion event might be very ancient indeed, preceding the divergence of bacteria and eukaryotes. It is unclear whether all the bacterial homologues are derived from horizontal gene transfer, but those from the plant symbionts probably are. The homologues from oceanic bacteria are most closely related to memapsins (or BACE-1 and BACE-2, but are so divergent that they are close to the root of the phylogenetic tree and to the division of the A1 family into two subfamilies.

  1. Sulfur-carbon nanocomposites and their application as cathode materials in lithium-sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Chengdu; Dudney, Nancy J; Howe, Jane Y

    2015-05-05

    The invention is directed in a first aspect to a sulfur-carbon composite material comprising: (i) a bimodal porous carbon component containing therein a first mode of pores which are mesopores, and a second mode of pores which are micropores; and (ii) elemental sulfur contained in at least a portion of said micropores. The invention is also directed to the aforesaid sulfur-carbon composite as a layer on a current collector material; a lithium ion battery containing the sulfur-carbon composite in a cathode therein; as well as a method for preparing the sulfur-composite material.

  2. Graphene-wrapped sulfur nanospheres with ultra-high sulfur loading for high energy density lithium–sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ya; Guo, Jinxin; Zhang, Jun, E-mail: zhangjun@zjnu.cn; Su, Qingmei; Du, Gaohui, E-mail: gaohuidu@zjnu.edu.cn

    2015-01-01

    Graphical abstract: - Highlights: • A graphene-wrapped sulfur nanospheres composite with 91 wt% S is prepared. • It shows highly improved electrochemical performance as cathode for Li–S cell. • The PVP coating and conductive graphene minimize polysulfides dissolution. • The flexible coatings with void space accommodate the volume expansion of sulfur. - Abstract: Lithium–sulfur (Li–S) battery with high theoretical energy density is one of the most promising energy storage systems for electric vehicles and intermittent renewable energy. However, due to the poor conductivity of the active material, considerable weight of the electrode is occupied by the conductive additives. Here we report a graphene-wrapped sulfur nanospheres composite (S-nanosphere@G) with sulfur content up to 91 wt% as the high energy density cathode material for Li–S battery. The sulfur nanospheres with diameter of 400–500 nm are synthesized through a solution-based approach with the existence of polyvinylpyrrolidone (PVP). Then the sulfur nanospheres are uniformly wrapped by conductive graphene sheets through the electrostatic interaction between graphene oxide and PVP, followed by reducing of graphene oxide with hydrazine. The design of graphene wrapped sulfur nanoarchitecture provides flexible conductive graphene coating with void space to accommodate the volume expansion of sulfur and to minimize polysulfide dissolution. As a result, the S-nanosphere@G nanocomposite with 91 wt% sulfur shows a reversible initial capacity of 970 mA h g{sup ?1} and an average columbic efficiency > 96% over 100 cycles at a rate of 0.2 C. Taking the total mass of electrode into account, the S-nanosphere@G composite is a promising cathode material for high energy density Li–S batteries.

  3. Graphene-wrapped sulfur nanospheres with ultra-high sulfur loading for high energy density lithium–sulfur batteries

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • A graphene-wrapped sulfur nanospheres composite with 91 wt% S is prepared. • It shows highly improved electrochemical performance as cathode for Li–S cell. • The PVP coating and conductive graphene minimize polysulfides dissolution. • The flexible coatings with void space accommodate the volume expansion of sulfur. - Abstract: Lithium–sulfur (Li–S) battery with high theoretical energy density is one of the most promising energy storage systems for electric vehicles and intermittent renewable energy. However, due to the poor conductivity of the active material, considerable weight of the electrode is occupied by the conductive additives. Here we report a graphene-wrapped sulfur nanospheres composite (S-nanosphere@G) with sulfur content up to 91 wt% as the high energy density cathode material for Li–S battery. The sulfur nanospheres with diameter of 400–500 nm are synthesized through a solution-based approach with the existence of polyvinylpyrrolidone (PVP). Then the sulfur nanospheres are uniformly wrapped by conductive graphene sheets through the electrostatic interaction between graphene oxide and PVP, followed by reducing of graphene oxide with hydrazine. The design of graphene wrapped sulfur nanoarchitecture provides flexible conductive graphene coating with void space to accommodate the volume expansion of sulfur and to minimize polysulfide dissolution. As a result, the S-nanosphere@G nanocomposite with 91 wt% sulfur shows a reversible initial capacity of 970 mA h g?1 and an average columbic efficiency > 96% over 100 cycles at a rate of 0.2 C. Taking the total mass of electrode into account, the S-nanosphere@G composite is a promising cathode material for high energy density Li–S batteries

  4. The isotopic composition of sulfur and the genesis of mirabilite from the Miocene Oya formation, Tochigi Prefecture

    International Nuclear Information System (INIS)

    The sulfur isotope ratios of mirabilite and gypsum from a pumice tuff formation of the Miocene ''green tuff'' group in Oya, Tochigi Prefecture, are remarkably light, being -16 to -20 in delta 34S per mil value relative to the meteoritic sulfur. Comparative isotopic values are observed for pyrites in the formation, which are considered to be of the syngenetic or diagenetic origin. The SO42- in the sulfate minerals is possibly derived from the near-surface oxidation of the biogenic sulfides. (Mori, K.)

  5. Sulfur turnover and emissions during storage of cattle slurry

    DEFF Research Database (Denmark)

    Eriksen, Jørgen; Andersen, Astrid J; Poulsen, Henrik Vestergaard; Adamsen, Anders Peter; Petersen, Søren O

    2012-01-01

    Slurry acidification using sulfuric acid reduces ammonia emissions but also affects sulfur (S) cycling. Emission of sulfur is a source of malodor and reduces the sulfur fertilizer value of the slurry. We investigated the effect of sulfate and methionine amendments, alone or in combination with acidification, on sulfur transformations in slurry and emissions of volatile sulfur compounds (VSC) during storage of fresh and aged cattle slurry. When pH was lowered to 5.5 it resulted in an almost compl...

  6. Characterization of Lactic Acid Bacteria Isolated from Sauce-type Kimchi

    OpenAIRE

    Jung, Suk Hee; Park, Joung Whan; Cho, Il Jae; Lee, Nam Keun; Yeo, In-Cheol; Kim, Byung Yong; Kim, Hye Kyung; Hahm, Young Tae

    2012-01-01

    This study was carried out to investigate the isolation and characterization of lactic acid bacteria (LAB) from naturally fermented sauce-type kimchi. Sauce-type kimchi was prepared with fresh, chopped ingredients (Korean cabbage, radish, garlic, ginger, green onion, and red pepper). The two isolated bacteria from sauce-type kimchi were identified as Pediococcus pentosaceus and Lactobacillus brevis by 16S rDNA sequencing and tentatively named Pediococcus sp. IJ-K1 and Lactobacillus sp. IJ-K2,...

  7. Selection and Characterization of Endophytic Bacteria as Biocontrol Agents of Tomato Bacterial Wilt Disease

    OpenAIRE

    ABDJAD ASIH NAWANGSIH; IKA DAMAYANTI; SURYO WIYONO; JUANG GEMA KARTIKA

    2011-01-01

    Biological control of bacterial wilt pathogen (Ralstonia solanacearum) of tomato using endophytic bacteria is one of the alternative control methods to support sustainable agriculture. This study was conducted to select and characterize endophytic bacteria isolated from healthy tomato stems and to test their ability to promote plant growth and suppress bacterial wilt disease. Among 49 isolates successfully isolated, 41 were non-plant pathogenic. Green house test on six selected isolates based...

  8. Stability of sulfur slopes on Io

    Science.gov (United States)

    Clow, G. D.; Carr, M. H.

    1980-01-01

    The mechanical properties of elemental sulfur are such that the upper crust of Io cannot be primarily sulfur. For heat flows in the range 100-1000 ergs/sq cm sec sulfur becomes ductile within several hundred meters of the surface and would prevent the formation of calderas with depths greater than this. However, the one caldera for which precise depth data are available is 2 km deep, and this value may be typical. A study of the mechanical equilibrium of simple slopes shows that the depth to the zone of rapid ductile flow strongly controls the maximum heights for sulfur slopes. Sulfur scarps with heights greater than 1 km will fail for all heat flows greater than 180 ergs/sq cm sec and slope angles greater than 22.5 deg. The observed relief on Io is inconsistent with that anticipated for a predominantly sulfur crust. However, a silicate crust with several percent sulfur included satisfies both the mechanical constraints and the observed presence of sulfur on Io.

  9. Pyrolysis of high sulfur Indian coals

    Energy Technology Data Exchange (ETDEWEB)

    B.P. Baruah; Puja Khare [RRL Jorhat, Assam (India). Coal Chemistry Division

    2007-12-15

    Pyrolysis experiments under laboratory conditions for five numbers of high sulfur coal samples from the states of Meghalaya and Nagaland, India, were carried out at temperatures of 450, 600, 850, and 1000{sup o}C, respectively. The yield of products and thermal release of sulfur from these coals are investigated. The distribution of sulfur in the pyrolyzed products, i.e., char/coke, gas, and tar, is also reported. Hydrocarbon and sulfurous gases released at different temperatures were analyzed by a gas chromatograph (GC) with an FID (flame ionized detector) and an FPD (flame photometric detector), respectively. H{sub 2}S evolution during coal pyrolysis was found to be a function of temperature up to 850{sup o}C. The low concentration of SO{sub 2} detected for some of the samples is due to decomposition of inorganic sulphates present. Evolution of methane for the coals tested increases with the increase of temperature. Maximum sulfur release was found in the range of 600-850{sup o}C and has a decreasing tendency from 850-1000{sup o}C, which might be due to the incorporation of sulfur released into the coal matrix. Activation energies for sulfur release were found in the range of 38-228 kJ mol{sup -1}, which were higher than the reported activation energies for lignites and bituminous coals mainly due to highly stable organic sulfur functionalities. 52 refs., 9 figs., 6 tabs.

  10. Sulfur removal from a gas stream

    International Nuclear Information System (INIS)

    There is disclosed a process for removing sulfur compounds from a gas stream. The process involves passing the gas stream containing the sulfur compounds through a mass of porous material that has deposited upon it a metal oxide, the improvement comprises the continuous or intermittent addition of an oxidizing agent and an amine

  11. Stabilized sulfur binding using activated fillers

    Energy Technology Data Exchange (ETDEWEB)

    Kalb, Paul D.; Vagin, Vyacheslav P.; Vagin, Sergey P.

    2015-07-21

    A method of making a stable, sulfur binding composite comprising impregnating a solid aggregate with an organic modifier comprising unsaturated hydrocarbons with at least one double or triple covalent bond between adjacent carbon atoms to create a modifier-impregnated aggregate; heating and drying the modifier-impregnated aggregate to activate the surface of the modifier-impregnated aggregate for reaction with sulfur.

  12. Ambient Air Monitoring for Sulfur Compounds

    Science.gov (United States)

    Forrest, Joseph; Newman, Leonard

    1973-01-01

    A literature review of analytical techniques available for the study of compounds at low concentrations points up some of the areas where further research is needed. Compounds reviewed are sulfur dioxide, sulfuric acid, ammonium sulfate and bisulfate, metal sulfates, hydrogen sulfide, and organic sulfides. (BL)

  13. Blue-green algae

    Science.gov (United States)

    “Blue-green algae” describes a large and diverse group of simple, plant-like organisms found in salt water and some large fresh water lakes. Blue-green algae products are used for many conditions, ...

  14. Metabolic Engineering and Modeling of Metabolic Pathways to Improve Hydrogen Production by Photosynthetic Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Y. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Navid, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2014-12-19

    Rising energy demands and the imperative to reduce carbon dioxide (CO2) emissions are driving research on biofuels development. Hydrogen gas (H2) is one of the most promising biofuels and is seen as a future energy carrier by virtue of the fact that 1) it is renewable, 2) does not evolve the “greenhouse gas” CO2 in combustion, 3) liberates large amounts of energy per unit weight in combustion (having about 3 times the energy content of gasoline), and 4) is easily converted to electricity by fuel cells. Among the various bioenergy strategies, environmental groups and others say that the concept of the direct manufacture of alternative fuels, such as H2, by photosynthetic organisms is the only biofuel alternative without significant negative criticism [1]. Biological H2 production by photosynthetic microorganisms requires the use of a simple solar reactor such as a transparent closed box, with low energy requirements, and is considered as an attractive system to develop as a biocatalyst for H2 production [2]. Various purple bacteria including Rhodopseudomonas palustris, can utilize organic substrates as electron donors to produce H2 at the expense of solar energy. Because of the elimination of energy cost used for H2O oxidation and the prevention of the production of O2 that inhibits the H2-producing enzymes, the efficiency of light energy conversion to H2 by anoxygenic photosynthetic bacteria is in principle much higher than that by green algae or cyanobacteria, and is regarded as one of the most promising cultures for biological H2 production [3]. Here implemented a simple and relatively straightforward strategy for hydrogen production by photosynthetic microorganisms using sunlight, sulfur- or iron-based inorganic substrates, and CO2 as the feedstock. Carefully selected microorganisms with bioengineered beneficial traits act as the biocatalysts of the process designed to both enhance the system efficiency of CO2 fixation and the net hydrogen production rate. Additionally we applied metabolic engineering approaches guided by computational modeling for the chosen model microorganisms to enable efficient hydrogen production.

  15. Depositional environment and sulfur distribution of high sulfur coal in Wuda mining area

    Energy Technology Data Exchange (ETDEWEB)

    Dai, S.; Ai, T.; Zhou, Q.; Ma, F.; Li, B. [China University of Mining and Technology (China)

    2000-10-01

    The horizontal distribution of depositional facies, coal facies and sulfur of high-sulfur coals in the Wuda coal mining area are analysed in this paper. The results show that there was a distinct influence of paleodrainage pattern on the sulfur distribution during the peat accumulating of coal seam No. 10. The sulfur distribution of coal seam No. 9 was influenced by the paleoenvironment during peat accumulation. The coal formed in shallow shelf or inter-distributary bay has high values of GI, TPI and sulfur content, whereas the coal formed in barrier sand bar has high content of sulfur and low values of GI and V/I, and the coal formed in lagoon has high values of GI and V/I and relatively low sulfur content. 3 refs., 7 figs.

  16. GREEN MARKETING - AN OVERVIEW

    OpenAIRE

    Arthi; S. Bulomine Reg; Anthony Rahul Golden.S

    2014-01-01

    In today's business world environmental issues plays an important role in marketing. All most all the governments around the world have concerned about green marketing activities that they have attempted to regulate them. There has been little attempt to academically examine environmental or green marketing. It introduces the terms and concepts of green marketing, briefly discuss why going green is important and also examine some of the reason that organizations are adopting a...

  17. Magnetotactic bacteria. Promising biosorbents for heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Wei; Zhang, Yanzong; Ding, Xiaohui; Liu, Yan; Shen, Fei; Zhang, Xiaohong; Deng, Shihuai; Xiao, Hong; Yang, Gang; Peng, Hong [Sichuan Agricultural Univ., Chengdu (China). Provincial Key Lab. of Agricultural Environmental Engineering

    2012-09-15

    Magnetotactic bacteria (MTB), which can orient and migrate along a magnetic line of force due to intracellular nanosized magnetosomes, have been a subject of research in the medical field, in dating environmental changes, and in environmental remediation. This paper reviews the recent development of MTB as biosorbents for heavy metals. Ultrastructures and taxis of MTB are investigated. Adsorptions in systems of unitary and binary ions are highlighted, as well as adsorption conditions (temperature, pH value, biomass concentration, and pretreatments). The separation and desorption of MTB in magnetic separators are also discussed. A green method to produce metal nanoparticles is provided, and an energy-efficient way to recover precious metals is put forward during biosorption. (orig.)

  18. The green agenda

    CERN Document Server

    Calder, Alan

    2009-01-01

    This business guide to Green IT was written to introduce, to a business audience, the opposing groups and the key climate change concepts, to provide an overview of a Green IT strategy and to set out a straightforward, bottom line-orientated Green IT action plan.

  19. EPA's Green Roof Research

    Science.gov (United States)

    This is a presentation on the basics of green roof technology. The presentation highlights some of the recent ORD research projects on green roofs and provices insight for the end user as to the benefits for green roof technology. It provides links to currently available EPA re...

  20. Sulfur and oxygen isotope study of sulfate reduction in experiments with natural populations from Fællestrand, Denmark

    Science.gov (United States)

    Farquhar, James; Canfield, Don E.; Masterson, Andrew; Bao, Huiming; Johnston, David

    2008-06-01

    This study investigates the sulfur and oxygen isotope fractionations of dissimilatory sulfate reduction and works to reconcile the relationships between the oxygen and sulfur isotopic and elemental systems. We report results of experiments with natural populations of sulfate-reducing bacteria using sediment and seawater from a marine lagoon at Fællestrand on the northern shore of the island of Fyn, Denmark. The experiments yielded relatively large magnitude sulfur isotope fractionations for dissimilatory sulfate reduction (up to approximately 45‰ for 34S/32S) with higher ?18O accompanying higher ?34S, similar to that observed in previous studies. The seawater used in the experiments was spiked by addition of 17O-labeled water and the 17O content of residual sulfate was found to depend on the fraction of sulfate reduced in the experiments. The 17O data provides evidence for recycling of sulfur from metabolic intermediates and for an 18O/16O fractionation of ?25-30‰ for dissimilatory sulfate reduction. The close correlation between the 17O data and the sulfur isotope data suggests that isotopic exchange between cell water and external water (reactor water) was rapid under experimental conditions. The molar ratio of oxygen exchange to sulfate reduction was found to be about 2.5. This value is slightly lower than observed in studies of natural ecosystems [e.g., Wortmann U. G., Chernyavsky B., Bernasconi S. M., Brunner B., Böttcher M. E. and Swart P. K. (2007) Oxygen isotope biogeochemistry of pore water sulfate in the deep biosphere: dominance of isotope exchange reactions with ambient water during microbial sulfate reduction (ODP Site 1130). Geochim. Cosmochim. Acta71, 4221-4232]. Using recent models of sulfur isotope fractionations we find that our combined sulfur and oxygen isotopic data places constraints on the proportion of sulfate recycled to the medium (78-96%), the proportion of sulfur intermediate sulfite that was recycled by way of APS to sulfate and released back to the external sulfate pool (?70%), and also that a fraction of the sulfur intermediates between sulfite and sulfide were recycled to sulfate. These parameters can be constrained because of the independent information provided by ?18O, ?34S, ?17O labels, and ?33S.

  1. Simultaneous bioreduction of nitrate and chromate using sulfur-based mixotrophic denitrification process

    Energy Technology Data Exchange (ETDEWEB)

    Sahinkaya, Erkan, E-mail: erkansahinkaya@yahoo.com [Istanbul Medeniyet University, Bioengineering Department, Goztepe, Istanbul (Turkey); Kilic, Adem [Harran University, Environmental Engineering Department, Osmanbey Campus, 63000 Sanliurfa (Turkey); Calimlioglu, Beste; Toker, Yasemin [Istanbul Medeniyet University, Bioengineering Department, Goztepe, Istanbul (Turkey)

    2013-11-15

    Highlights: • Simultaneous heterotrophic and autotrophic denitrification was stimulated. • Simultaneous bioreduction of nitrate and chromate was achieved. • Total chromium decreased <50 ?g/L when the influent Cr(VI) was ?5 mg/L. -- Abstract: This study aims at evaluating simultaneous chromate and nitrate reduction using sulfur-based mixotrophic denitrification process in a column reactor packed with elemental sulfur and activated carbon. The reactor was supplemented with methanol at C/N ratio of 1.33 or 2. Almost complete denitrification was achieved at influent NO{sub 3}{sup ?}–N and Cr(VI) concentrations of 75 mg/L and 10 mg/L, respectively, and 3.7 h HRT. Maximum denitrification rate was 0.5 g NO{sub 3}{sup ?}–N/(L.d) when the bioreactor was fed with 75 mg/L NO{sub 3}{sup ?}–N, 150 mg/L methanol and 10 mg/L Cr(VI). The share of autotrophic denitrification was between 12% and 50% depending on HRT, C/N ratio and Cr(VI) concentration. Effluent total chromium was below 50 ?g/L provided that influent Cr(VI) concentration was equal or below 5 mg/L. DGGE results showed stable microbial community throughout the operation and the presence of sulfur oxidizing denitrifying bacteria (Thiobacillus denitrificans) and Cr(VI) reducing bacteria (Exiguobacterium spp.) in the column bed.

  2. Tail tip proteins related to bacteriophage ? gpL coordinate an iron-sulfur cluster.

    Science.gov (United States)

    Tam, William; Pell, Lisa G; Bona, Diane; Tsai, Alex; Dai, Xiao Xian; Edwards, Aled M; Hendrix, Roger W; Maxwell, Karen L; Davidson, Alan R

    2013-07-24

    The assembly of long non-contractile phage tails begins with the formation of the tail tip complex (TTC). TTCs are multi-functional protein structures that mediate host cell adsorption and genome injection. The TTC of phage ? is assembled from multiple copies of eight different proteins, including gpL. Purified preparations of gpL and several homologues all displayed a distinct reddish color, suggesting the binding of iron by these proteins. Further characterization of the gpL homologue from phage N15, which was most amenable to in vitro analyses, showed that it contains two domains. The C-terminal domain was demonstrated to coordinate an iron-sulfur cluster, providing the first example of a viral structural protein binding to this type of metal group. We characterized the iron-sulfur cluster using inductively coupled plasma-atomic emission spectroscopy, absorbance spectroscopy, and electron paramagnetic resonance spectroscopy and found that it is an oxygen-sensitive [4Fe-4S](2+) cluster. Four highly conserved cysteine residues were shown to be required for coordinating the iron-sulfur cluster, and substitution of any of these Cys residues with Ser or Ala within the context of ? gpL abolished biological activity. These data imply that the intact iron-sulfur cluster is required for function. The presence of four conserved Cys residues in the C-terminal regions of very diverse gpL homologues suggest that utilization of an iron-sulfur cluster is a widespread feature of non-contractile tailed phages that infect Gram-negative bacteria. In addition, this is the first example of a viral structural protein that binds an iron-sulfur cluster. PMID:23542343

  3. Bacteria in solitary confinement.

    Science.gov (United States)

    Mullineaux, Conrad W

    2015-02-15

    Even in clonal bacterial cultures, individual bacteria can show substantial stochastic variation, leading to pitfalls in the interpretation of data derived from millions of cells in a culture. In this issue of the Journal of Bacteriology, as part of their study on osmoadaptation in a cyanobacterium, Nanatani et al. describe employing an ingenious microfluidic device that gently cages individual cells (J Bacteriol 197:676-687, 2015, http://dx.doi.org/10.1128/JB.02276-14). The device is a welcome addition to the toolkit available to probe the responses of individual cells to environmental cues. PMID:25488297

  4. Bacteria in Solitary Confinement

    OpenAIRE

    Mullineaux, Conrad W

    2014-01-01

    Even in clonal bacterial cultures, individual bacteria can show substantial stochastic variation, leading to pitfalls in the interpretation of data derived from millions of cells in a culture. In this issue of the Journal of Bacteriology, as part of their study on osmoadaptation in a cyanobacterium, Nanatani et al. describe employing an ingenious microfluidic device that gently cages individual cells (J Bacteriol 197:676–687, 2015, http://dx.doi.org/10.1128/JB.02276-14). The device is a welco...

  5. Improving green roofs and rail road greening systems using Bacillus subtilis and Lactobacillus ssp.

    Science.gov (United States)

    Grüneberg, H; Oschmann, C; Dunya, S; Ulrichs, C

    2006-01-01

    Aim of the present study was the improvement of existing methods for green roof and rail road greening systems using soil borne bacteria. Bacillus subtilis and Lactobacillus ssp. alone and in combination with vinasse applied to different growing substrates were tested. The substrates were brick chips, textile mats, mineral wool mats, and a commercial available substrate for the Swedish company VegTech. All four substrates were tested along an artificial rail track on the experimental station at Humboldt University Berlin, and partly on an existing rail track in Munich, Germany. Plants selected for the experiments belong to the genus Sedum, which is relatively tolerant to dry conditions. Inoculation of plants with bacteria had no effect on plant growth parameters and on coverage of different mobile bedding systems with Sedum plants. There was no significant difference between the various treatments in Munich. In both experiments, the addition of vinasse alone improved plant growth. Plant growth was significantly different on all substrates, whereas brick chips and the commercial roof soil was the best substrate. Brick chips are a cheap substrate which can be used for rail track greening. The results indicate that the quality of the substrate is the most important factor for remediation and greening of rail tracks and roof tops. The rapid growth of plants can be influenced by the application of vinasse as additional nutrient solution (potash (K) source) or nutrient enriched substrate. PMID:17390783

  6. A mesoporous carbon–sulfur composite as cathode material for high rate lithium sulfur batteries

    International Nuclear Information System (INIS)

    Highlights: • CMK-3 mesoporous carbon was synthesized as conducting reservoir for housing sulfur. • Sulfur/CMK-3 composites were prepared by two-stage thermal treatment. • The composite at 300 °C for 20 h shows improved electrochemical properties. - Abstract: Sulfur composite was prepared by encapsulating sulfur into CMK-3 mesoporous carbon with different heating times and then used as the cathode material for lithium sulfur batteries. Thermal treatment at 300 °C plays an important role in the sulfur encapsulation process. With 20 h of heating time, a portion of sulfur remained on the surface of carbon, whereas with 60 h of heating time, sulfur is confined deeply in the small pores of carbon that cannot be fully exploited in the redox reaction, thus causing low capacity. The S/CMK-3 composite with thermal treatment for 40 h at 300 °C contained 51.3 wt.% sulfur and delivered a high initial capacity of 1375 mA h g?1 at 0.1 C. Moreover, it showed good capacity retention of 704 mA h g?1 at 0.1 C and 578 mA h g?1 at 2 C even after 100 cycles, which proves its potential as a cathode material for high capability lithium sulfur batteries

  7. Sulfur isotope studies of biogenic sulfur emissions at Wallops Island, Virginia

    International Nuclear Information System (INIS)

    This research attempted to determine whether it is possible to measure the stable sulfur isotope distributions of atmospheric particulate and gaseous sulphur, and to use this information together with measurements of the ambient levels of sulfur gases and particulate sulfate and sodium in testing certain hypotheses. Sulfur dioxide and particulate sulfur samples were collected at a coastal marine location and their delta (34)S values were determined. These data were used together with sodium concentrations to determine the presence of biogenic sulfur and the identity of the biological processes producing it. Excess (non-seasalt) sulfate levels ranged from 2 to 26 micrograms/cu m and SO2 from 1 to 9 ppb. Analyses of air mass origins and lead concentrations indicated that some anthropogenic contaminants were present on all days, but the isotope data revealed that most of the atmospheric sulfur originated locally from the metabolism of bacterial sulfate reducers on all days, and that the atmospheric reactions leading to the production of sulfate from this biogenic sulfur source are extremely rapid. Delta34S values of atmospheric sulfur dioxide correlated well with those of excess sulfate, and implied little or no sulfur isotope fractionation during the oxidation of sulfur gases to sulfate

  8. A Flow-Cytometric Gram-Staining Technique for Milk-Associated Bacteria

    OpenAIRE

    Holm, Claus; Jespersen, Lene

    2003-01-01

    A Gram-staining technique combining staining with two fluorescent stains, Oregon Green-conjugated wheat germ agglutinin (WGA) and hexidium iodide (HI) followed by flow-cytometric detection is described. WGA stains gram-positive bacteria while HI binds to the DNA of all bacteria after permeabilization by EDTA and incubation at 50°C for 15 min. For WGA to bind to gram-positive bacteria, a 3 M potassium chloride solution was found to give the highest fluorescence intensity. A total of 12 strains...

  9. Determination of Poly-b-hydroxybutyrate (PHB) Production by Some Mesophilic and Thermophilic Lactic Acid Bacteria

    OpenAIRE

    Yüksekda?, Zehra Nur; BEYATLI, Yavuz; ASLIM, Belma

    2003-01-01

    Accumulated poly-b-hydroxybutyrate (PHB) was determined in lactic acid bacteria belonging to the genera Lactobacillus, Lactococcus and Streptococcus. Lactobacilli were grown in MRS broth and the others were grown in Elliker broth medium. Cell biomass was obtained by centrifugation. The cell walls were lysed with sodium hypochlorite. Poly-b-hydroxybutyrate was extracted using chloroform in a Soxhlet system. Then it was converted to crotonic acid using sulfuric acid and the amount of crotonic a...

  10. Microbial contributions to cave formation: New insights into sulfuric acid speleogenesis

    Science.gov (United States)

    Summers Engel, Annette; Stern, Libby A.; Bennett, Philip C.

    2004-05-01

    The sulfuric acid speleogenesis (SAS) model was introduced in the early 1970s from observations of Lower Kane Cave, Wyoming, and was proposed as a cave-enlargement process due to primarily H2S autoxidation to sulfuric acid and subaerial replacement of carbonate by gypsum. Here we present a reexamination of the SAS type locality in which we make use of uniquely applied geochemical and microbiological methods. Little H2S escapes to the cave atmosphere, or is lost by abiotic autoxidation, and instead the primary H2S loss mechanism is by subaqueous sulfur-oxidizing bacterial communities that consume H2S. Filamentous “Epsilonproteobacteria” and Gammaproteobacteria, characterized by fluorescence in situ hybridization, colonize carbonate surfaces and generate sulfuric acid as a metabolic byproduct. The bacteria focus carbonate dissolution by locally depressing pH, compared to bulk cave waters near equilibrium or slightly supersaturated with calcite. These findings show that SAS occurs in subaqueous environments and potentially at much greater phreatic depths in carbonate aquifers, thereby offering new insights into the microbial roles in subsurface karstification.

  11. Interactions between Diatoms and Bacteria

    OpenAIRE

    Amin, Shady A.; Parker, Micaela S; Armbrust, E Virginia

    2012-01-01

    Summary: Diatoms and bacteria have cooccurred in common habitats for hundreds of millions of years, thus fostering specific associations and interactions with global biogeochemical consequences. Diatoms are responsible for one-fifth of the photosynthesis on Earth, while bacteria remineralize a large portion of this fixed carbon in the oceans. Through their coexistence, diatoms and bacteria cycle nutrients between oxidized and reduced states, impacting bioavailability and ultimately feeding hi...

  12. Trail following by gliding bacteria.

    OpenAIRE

    Burchard, R P

    1982-01-01

    Slime trails, which are deposited on surfaces by gliding bacteria and which serve as preferential pathways for gliding motility, were tested for the species specificity of their support of movement. Among the pairs of bacteria tested, a variety of gliding bacteria and a flagellated bacterium moved along trails of unrelated species. Thus, the trails did not serve as pheromones. Rather, they may have guided gliding elasticotactically. Some biological implications of this finding are considered.

  13. Active skeleton for bacteria modeling

    OpenAIRE

    Jacob, Jean-Pascal; Dimiccoli, Mariella; Moisan, Lionel

    2015-01-01

    The investigation of spatio-temporal dynamics of bacterial cells and their molecular components requires automated image analysis tools to track cell shape properties and molecular component locations inside the cells. In the study of bacteria aging, the molecular components of interest are protein aggregates accumulated near bacteria boundaries. This particular location makes very ambiguous the correspondence between aggregates and cells, since computing accurately bacteria...

  14. Bacteria transport under unsaturated conditions

    OpenAIRE

    Gargiulo, G

    2006-01-01

    The aim of this work was to study the bacteria transport behaviour in different conditions using an unsaturated porous media. A column based system able to keep the unsaturated conditions was designed and developed to perform the experiments. Two bacteria strains Deinococcus radiodurans and Rhodococcus rhodochrous strongly different in hydrophobicity were employed. During the experiments the bacteria concentration in the outflow was continuously on-line measured and after the experiment the c...

  15. Engineered bacteria as therapeutic agents.

    Science.gov (United States)

    Piñero-Lambea, Carlos; Ruano-Gallego, David; Fernández, Luis Ángel

    2015-12-01

    Although bacteria are generally regarded as the causative agents of infectious diseases, most bacteria inhabiting the human body are non-pathogenic and some of them can be turned, after proper engineering, into 'smart' living therapeutics of defined properties for the treatment of different illnesses. This review focuses on recent developments to engineer bacteria for the treatment of diverse human pathologies, including inflammatory bowel diseases, autoimmune disorders, cancer, metabolic diseases and obesity, as well as to combat bacterial and viral infections. We discuss significant advances provided by synthetic biology to fully reprogram bacteria as human therapeutics, including novel measures for strict biocontainment. PMID:26070111

  16. Investigation of sugar sulfur carrier in nickel

    International Nuclear Information System (INIS)

    For the purposes of galvanotechnics it is necessary to have nickel which is easely subjected to the anode dissolving (the so called depolarized nickel). In the industry, nickel of such a quality is produced by the method of electrolytic sedimentation from the nickel solution in the presence of sulfur carriers, usually in the presence of saccharin. To study behaviour of saccharin in the process of electrolysis, investigations of saccharin labelled by sulfur-35 have been done. These investigations have permitted to determine the type and quantity of products of decomposition formed, as well as to determine possibilities for rising the quantity of introducer sulfur due to the variants of technological process

  17. Electronic structure of sulfur under high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Nishikawa, A [Chiba-Keizai College, 4-3-30 Todoroki-cho, Inage-ku, Chiba 263-0021 (Japan)], E-mail: nisikawa@chiba-kc.ac.jp

    2008-07-15

    We have calculated the bandstructures and the total energies of the high-pressure phases of sulfur by means of the full potential linearized APW (FP-LAPW) method to investigate the structural stability. The tetragonal sulfur-II phase with spiral chain structure is a semiconductor with narrow energy gap, whereas the monoclinic sulfur-III with incommensurate modulation is metallic and the modulation yields a large dip near the Fermi-level of the density of states and contributes to the lowering of the bandstructure energy.

  18. Carbon and sulfur relationships in Devonian shales from the Appalachian Basin as an indicator of environment of deposition.

    Science.gov (United States)

    Leventhal, J.S.

    1987-01-01

    Interprets the covariance of organic carbon and sulfide sulfur in core samples. This covariance results from the catabolism of organic carbon and concomitant reduction of sulfate by sulfate reducing bacteria to form aqueous sulfide which reacts with iron. Defines a central basin area that was the most anoxic-sulfidic (euxinic). This part of the basin is similar to the area of thickest, most organic carbon-rich sediments and has the greatest source-rock potential for petroleum. -from Author

  19. Sulfurized carbon: a class of cathode materials for high performance lithium/sulfur batteries

    Directory of Open Access Journals (Sweden)

    ShengS.Zhang

    2013-12-01

    Full Text Available Liquid electrolyte lithium/sulfur (Li/S batteries cannot come into practical applications because of many problems such as low energy efficiency, short cycle life, and fast self-discharge. All these problems are related to the dissolution of lithium polysulfide, a series of sulfur reduction intermediates, in the liquid electrolyte, and resulting parasitic reactions with the Li anode. Covalently binding sulfur onto carbon surface is a solution to completely eliminate the dissolution of lithium polysulfide and make the Li/S battery viable for practical applications. This can be achieved by replacing elemental sulfur with sulfurized carbon as the cathode material. This article reviews the current efforts on this subject and discusses the syntheses, electrochemical properties, and prospects of the sulfurized carbon as a cathode material in the rechargeable Li/S batteries.

  20. Sulfur-K? /sub emission studies on sulfur-bearing heterocycles

    International Nuclear Information System (INIS)

    Sulfur-K/? /sub x-ray fluorescence spectroscopy (XFS) has been used to study the electronic structure and bonding in sulfur-bearing heterocycles. XFS not only has the capability of experimentally measuring valence electron energies in molecular species, but can also provide intensity data which can help define the nature of the molecular orbitals defined by the electrons. This report discusses the feasibility of using XFS as an analytical tool for the determination of total and specific sulfur heterocycle content in samples. A variety of compounds were studied. These include thiophene, thiophene derivatives, tetranydrothiophene, several more complex saturated and unsaturated sulfur heterocycles, and heterocycles containing both sulfur and nitrogen. The sulfur-K/? /sub spectra were obtained using a double crystal spectrometer which provided an instrumental resolution of about 0.7 eV

  1. 46 CFR 151.50-21 - Sulfuric acid.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Sulfuric acid. 151.50-21 Section 151.50-21 Shipping... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-21 Sulfuric acid. (a) How sulfuric acid may be carried. (1) Sulfuric acid of concentration of 77.5 percent (1.7019 specific gravity)...

  2. Extracellular communication in bacteria

    DEFF Research Database (Denmark)

    Chhabra, S.R.; Philipp, B.

    2005-01-01

    Populations of bacterial cells often coordinate their responses to changes in their local environmental conditions through "quorum sensing", a cell-to-cell communication system employing small diffusible signal molecules. While there is considerable diversity in the chemistry of such signal molecules, in different Gram-positive and Gram-negative bacteria they control pathogenicity, secondary metabolite production, biofilm differentiation, DNA transfer and bioluminescence. The development of biosensors for the detection of these signal molecules has greatly facilitated their subsequent chemical analysis which in turn has resulted in significant progress in understanding the molecular basis of quorum sensing-dependent gene expression. Consequently, the discovery and characterisation of natural molecules which antagonize quorum sensing-mediated responses has created new opportunities for the design of novel anti-infective agents which control infection through the attenuation of bacterial virulence.

  3. Effect of sulfur dioxide partial pressure on the reaction of iodine, sulfur dioxide and water

    International Nuclear Information System (INIS)

    Effect of sulfur dioxide partial pressure on the reaction of iodine, sulfur dioxide and water, which is a unit reaction in the IS process for thermochemical hydrogen production, was studied experimentally at 323 K under iodine saturation. Quasi-equilibrium state was observed in the presence of sulfur dioxide gas at constant pressure. The composition of the poly-hydriodic acid solution formed was discussed assuming an ideal desulfurization by the reverse reaction of the Bunsen reaction. The value of HI/(HI+H2O) of the desulfurized solution was large at high sulfur dioxide pressure and reached the maximum of 15.7 ± 0.3 mol%. (author)

  4. ROE Total Sulfur Deposition 2011-2013

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset identifies the amount of wet, dry, and total deposition of sulfur in kilograms per hectare from 2011 to 2013 at a set of point locations across the...

  5. ROE Total Sulfur Deposition 1989-1991

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset identifies the amount of wet, dry, and total deposition of sulfur in kilograms per hectare from 1989 to 1991 at a set of point locations across the...

  6. Effects of sulfur dioxide and heavy metals

    International Nuclear Information System (INIS)

    Produced from burning coal, sulfur dioxide persists not so much from home heating as in the furnaces of coal-fired, electric power-generating plants. Particulate emissions may be over 99% controlled, and sulfur dioxide may be 70-90% controlled in some countries, but older plants or newer facilities in developing countries often lack such technology. Even where controls exist, the tremendous amounts of coal burned still result in the emission of significant quantities of sulfur dioxide. And despite pollution control equipment in modern smelters, the sulfur dioxide and heavy metal particulate emissions can still damage neighboring vegetation. The problem is especially critical in developing countries where control technology is lacking, or in developed countries where control has a low priority

  7. SULFUR COMPOUNDS IN PETROLEUM HYDROCARBON STREAMS

    Directory of Open Access Journals (Sweden)

    Antoaneta Pavlova

    2012-03-01

    Full Text Available Determination of concentrations of sulfur compounds in different petroleum samples is a true analytical challenge. Only analytical procedures based on gas chromatography can meet the sensitivity and accuracy requirements dictated by up-to-date petroleum industry.The objective of this work is to develop the method for the quantifying of sulfur compounds in petroleum hydrocarbon streams. The optimum parameters for the GC-SCD method are found in order to determine of sulfur compounds in petroleum fractions. The present study is limited to fractions with final boiling point up to 100°C from the refining unit. Twelve petroleum samples are analyzed. The total sulfur contents of these samples are determined by GC-SCD and UV fluorescence detection. The data obtained are agreement.

  8. Environmental behavior and analysis of agricultural sulfur.

    Science.gov (United States)

    Griffith, Corey M; Woodrow, James E; Seiber, James N

    2015-11-01

    Sulfur has been widely used for centuries as a staple for pest and disease management in agriculture. Presently, it is the largest-volume pesticide in use worldwide. This review describes the sources and recovery methods for sulfur, its allotropic forms and properties and its agricultural uses, including development and potential advantages of nanosulfur as a fungicide. Chemical and microbial reactivity, interactions in soil and water and analytical methods for determination in environmental samples and foodstuffs, including inexpensive analytical methods for sulfur residues in wine, beer and other food/beverage substrates, will be reviewed. The toxicology of sulfur towards humans and agriculturally important fungi is included, with some restrictions on use to promote safety. The review concludes with areas for which more research is warranted. © 2015 Society of Chemical Industry. PMID:26108794

  9. Sulfur Dioxide variability in the Venus Atmosphere

    Science.gov (United States)

    Vandaele, A. C.; Korablev, O.; Mahieux, A.; Wilquet, V.; Chamberlain, S.; Belayev, D.; Encrenaz, Th.; Esposito, L.; Jessup, K. L.; Lefèvre, F.; Limaye, S.; Marcq, E.; Mils, F.; Parkinson, C.; Sandor, B.; Stolzenbach, A.; Wilson, C.

    2015-10-01

    Recent observations of sulfur oxides (SO2, SO, OCS, and H2 SO4) in Venus' mesosphere have generated controversy and great interest in the scientific community. These observations revealed u nexpected spatial patterns and spatial/temporal variability that have not been satisfactorily explained by models. Particularly intriguing are the layer of enhanced gas-phase SO2 and SO in the upper mesosphere, and variability in the maximum observed SO2 a bundance and the equator -to-pole SO2 abundance gradient, seemingly on multi-year cycles, that is not uniquely linked to local time variations. Sulfur oxide chemistry on Venus is closely linked to the global-scale cloud and haze layers, which are composed primarily of concentrated sulfuric acid. Consequently, sulfur oxide observations provide important insight into the ongoing chemical evolution of Venus' atmosphere, atmospheric dynamics, and possible volcanism.

  10. Rapid method for detection of adherent bacteria on Foley urinary catheters.

    OpenAIRE

    Ladd, T I; Schmiel, D; Nickel, J C; Costerton., J.W.

    1985-01-01

    An accurate, rapid, and inexpensive method was developed for detecting and enumerating bacteria adherent to Foley urinary catheters based on malachite green staining of acridine orange-prestained specimens. This method has proven to be quick and reliable and will find application in quantitative studies of biomaterial-related sepsis.

  11. Microbiological disproportionation of inorganic sulfur compounds

    DEFF Research Database (Denmark)

    Finster, Kai

    2008-01-01

    The disproportionation of inorganic sulfur intermediates at moderate temperatures (0-80 °C) is a microbiologically catalyzed chemolithotrophic process in which compounds like elemental sulfur, thiosulfate, and sulfite serve as both electron donor and acceptor, and generate hydrogen sulfide and sulfate. Thus the overall process is comparable to the fermentation of organic compounds such as glucose and is consequently often described as 'inorganic fermentation'. The process is primarily carried ou...

  12. Anthropogenic sulfur dioxide emissions: 1850–2005

    OpenAIRE

    Smith, S.J.; J. Van Aardenne; Klimont, Z.; Andres, R.; A. Volke; S. Delgado Arias

    2010-01-01

    Sulfur aerosols impact human health, ecosystems, agriculture, and global and regional climate. A new annual estimate of anthropogenic global and regional sulfur dioxide emissions has been constructed spanning the period 1850–2005 using a bottom-up mass balance method, calibrated to country-level inventory data. Global emissions peaked in the early 1970s and decreased until 2000, with an increase in recent years due to increased emissions in China, international shipping, and developing...

  13. Polymer Electrolytes for Lithium/Sulfur Batteries

    OpenAIRE

    The Nam Long Doan; Denise Gosselink; Yongguang Zhang; Mikhail Sadhu; Ho-Jae Cheang; Pu Chen; Yan Zhao

    2012-01-01

    This review evaluates the characteristics and advantages of employing polymer electrolytes in lithium/sulfur (Li/S) batteries. The main highlights of this study constitute detailed information on the advanced developments for solid polymer electrolytes and gel polymer electrolytes, used in the lithium/sulfur battery. This includes an in-depth analysis conducted on the preparation and electrochemical characteristics of the Li/S batteries based on these polymer electrolytes.

  14. Polymer Electrolytes for Lithium/Sulfur Batteries

    Directory of Open Access Journals (Sweden)

    The Nam Long Doan

    2012-08-01

    Full Text Available This review evaluates the characteristics and advantages of employing polymer electrolytes in lithium/sulfur (Li/S batteries. The main highlights of this study constitute detailed information on the advanced developments for solid polymer electrolytes and gel polymer electrolytes, used in the lithium/sulfur battery. This includes an in-depth analysis conducted on the preparation and electrochemical characteristics of the Li/S batteries based on these polymer electrolytes.

  15. Reactions between Methanethiol and Biologically Produced Sulfur

    OpenAIRE

    van Leerdam, R. C.; Bosch, P.L.F., van den; Lens, P.; Janssen, A. J. H.

    2011-01-01

    Recently, new biotechnological processes have been developed to enable the sustainable removal of organic and inorganic sulfur compounds from liquid and gaseous hydrocarbon streams. In comparison to existing technologies (e.g., caustic scrubbing or iron based redox technologies) far less chemicals are consumed, while reusable elemental sulfur is formed as the main end-product. This research shows that in these processes a number of consecutive reactions occur between methanethiol (MT) from th...

  16. Biologically produced sulfur particles and polysulfide ions

    OpenAIRE

    Kleinjan, W. E.

    2005-01-01

    This thesis deals with the effects of particles of biologically produced sulfur (or 'biosulfur') on a biotechnological process for the removal of hydrogen sulfide from gas streams. Particular emphasis is given to the role of polysulfide ions in such a process. These polysulfide ions are formed from reaction of sulfide with biologically produced sulfur. The basic concepts of this H 2 S removal process were developed at the department of Environmental Technology of Wageningen University and the...

  17. Removing sulfur oxides from a gas

    Energy Technology Data Exchange (ETDEWEB)

    Bertolacini, R.J.; Hirschberg, E.H.; Modica, F.S.

    1983-03-08

    Sulfur oxides are removed from a gas with absorbents and then are removed from the absorbents by contact with a hydrocarbon in the presence of a cracking catalyst. The absorbents comprise an exhaustively-exchanged rare-earth-form zeolite and a free form of an inorganic oxide selected from the group consisting of the oxides of aluminum, magnesium, zinc, titanium, and calcium. The sulfur oxides are removed from the absorbents as a sulfurcontaining gas which comprises hydrogen sulfide.

  18. Manufacturing Green Consensus

    DEFF Research Database (Denmark)

    Gulsrud, Natalie Marie; Ooi, Can Seng

    2014-01-01

    In an increasingly global economy, being green, or having an environmentally sustainbale place brand, provides a competitive advantage. Singapore, long known as the ``garden city´´ has been a leader in green city imaging since the founding of the equatorial city-state, contributing, in large part to the city’s profile as the economic giant of Southeast Asia. Using a political ecology lens, the paper aims to uncover the contested socio-economic narratives of green city imaging by examining the ev...

  19. Measuring green jobs?

    DEFF Research Database (Denmark)

    Zandersen, Marianne; Martinsen, Louise

    2012-01-01

    The report reviews the different initiatives aiming to measure aspects of “green” sectors, jobs and technologies. The report discusses whether the statistics collected under the present initiatives aimed at measuring these aspects increase insights into the fundamental questions motivating the initiatives. An alternative framework is suggested, as it appears fundamentally impossible to make consistent frameworks for a division of the economy into “green” and “non-green” activities. The analysis ...

  20. Green growth in fisheries

    DEFF Research Database (Denmark)

    Nielsen, Max; Ravensbeck, Lars; Nielsen, Rasmus

    2014-01-01

    Climate change and economic growth have gained a substantial amount of attention over the last decade. Hence, in order to unite the two fields of interest, the concept of green growth has evolved. The concept of green growth focuses on how to achieve growth in environment-dependent sectors, without harming the environment. Fishery is an environment-dependent sector and it has been argued that there is no potential for green growth in the sector owing to global overexploitation, leaving no scope ...

  1. Green tobacco sickness

    OpenAIRE

    McBride, J.; Altman, D; Klein, M.; White, W

    1998-01-01

    OBJECTIVE—To describe the health impact of harvesting tobacco and to suggest prevention and risk reduction strategies to avoid contracting green tobacco sickness (GTS).?DATA SOURCES—A literature search of Medline, Toxline, and Toxline65 with the terms "green", "tobacco", and "sickness" covering the years 1966-1998.?STUDY SELECTION—All studies, reviews, and commentaries that provided information on the health effects of harvesting green tobacco and disease prevention strategies.?DATA SYNTHESIS...

  2. Sulfur "Concrete" for Lunar Applications - Sublimation Concerns

    Science.gov (United States)

    Grugel, Richard N.; Toutanji, Houssam

    2006-01-01

    Melting sulfur and mixing it with an aggregate to form "concrete" is commercially well established and constitutes a material that is particularly well-suited for use in corrosive environments. Discovery of the mineral troilite (FeS) on the moon poses the question of extracting the sulfur for use as a lunar construction material. This would be an attractive alternative to conventional concrete as it does not require water. However, the viability of sulfur concrete in a lunar environment, which is characterized by lack of an atmosphere and extreme temperatures, is not well understood. Here it is assumed that the lunar ore can be mined, refined, and the raw sulfur melded with appropriate lunar regolith to form, for example, bricks. This study evaluates pure sulfur and two sets of small sulfur concrete samples that have been prepared using JSC-1 lunar stimulant and SiO2 powder as aggregate additions. Each set was subjected to extended periods in a vacuum environment to evaluate sublimation issues. Results from these experiments are presented and discussed within the context of the lunar environment.

  3. Sulfur isotope homogeneity of lunar mare basalts

    Science.gov (United States)

    Wing, Boswell A.; Farquhar, James

    2015-12-01

    We present a new set of high precision measurements of relative 33S/32S, 34S/32S, and 36S/32S values in lunar mare basalts. The measurements are referenced to the Vienna-Canyon Diablo Troilite (V-CDT) scale, on which the international reference material, IAEA-S-1, is characterized by ?33S = -0.061‰, ?34S ? -0.3‰ and ?36S = -1.27‰. The present dataset confirms that lunar mare basalts are characterized by a remarkable degree of sulfur isotopic homogeneity, with most new and published SF6-based sulfur isotope measurements consistent with a single mass-dependent mean isotopic composition of ?34S = 0.58 ± 0.05‰, ?33S = 0.008 ± 0.006‰, and ?36S = 0.2 ± 0.2‰, relative to V-CDT, where the uncertainties are quoted as 99% confidence intervals on the mean. This homogeneity allows identification of a single sample (12022, 281) with an apparent 33S enrichment, possibly reflecting cosmic-ray-induced spallation reactions. It also reveals that some mare basalts have slightly lower ?34S values than the population mean, which is consistent with sulfur loss from a reduced basaltic melt prior to eruption at the lunar surface. Both the sulfur isotope homogeneity of the lunar mare basalts and the predicted sensitivity of sulfur isotopes to vaporization-driven fractionation suggest that less than ?1-10% of lunar sulfur was lost after a potential moon-forming impact event.

  4. Improving the stability of probiotic bacteria in model fruit juices using vitamins and antioxidants.

    Science.gov (United States)

    Shah, N P; Ding, W K; Fallourd, M J; Leyer, G

    2010-06-01

    This study examined the survival of probiotic bacteria in a model fruit juice system. Three different strains of probiotic bacteria were used in this study: HOWARU Lactobacillus rhamnosus HN001, HOWARU Bifidobacterium lactis HN001, and Lactobacillus paracasei LPC 37. The probiotic bacteria were inoculated into model juice with various vitamins and antioxidants, namely white grape seed extract, green tea extract, vitamin B2, vitamin B3, vitamin B6, vitamin C, and vitamin E. The model juice without any additives was used as a control. Their viability was assessed on a weekly basis using plate count method. The model juice was made with sucrose, sodium citrate, citric acid powder, and distilled water and was pasteurized before use. Our findings showed that probiotic bacteria did not survive well in the harsh environment of the model fruit juice. However, the model juice containing vitamin C, grape extract, and green tea extract showed better survival of probiotic bacteria. The model juice containing grape seed extract, green tea extract, and vitamin C had the same initial population of 8.32 log CFU/mL, and at the end of the 6-wk storage period it had an average viability of 4.29 log CFU/mL, 7.41 log CFU/mL, and 6.44 log CFU/mL, respectively. Juices containing all other ingredients tested had viable counts of <10 CFU/mL at the end of the 6-wk storage period. PMID:20629884

  5. Green electricity buyer's guide

    International Nuclear Information System (INIS)

    The electricity produced in whole or in large part from renewable energy sources like wind, small hydro electricity and solar energy, is generally referred to as green electricity. The authors designed this buyer's guide to assist customers in their understanding of green electricity, as the customers can now choose their electricity supplier. The considerations and steps involved in the purchasse of green electricity are identified, and advice is provided on ways to maximize the benefits from the purchase of green electricity. In Alberta and Ontario, customers have access to a competitive electricity market. The emphasis when developing this guide was placed firmly on the large buyers, as they can have enormous positive influence on the new market for green electricity. The first chapter of the document provides general information on green electricity. In chapter two, the authors explore the opportunity for environmental leadership. Chapter three reviews the basics of green electricity, which provides the link to chapter four dealing with the creation of a policy. Purchasing green electricity is dealt with in Chapter five, and maximizing the benefits of green electricity are examined in Chapter Six. 24 refs., 3 tabs

  6. Microphysical simulations of sulfur burdens from stratospheric sulfur geoengineering

    Directory of Open Access Journals (Sweden)

    J. M. English

    2012-01-01

    Full Text Available Recent microphysical studies suggest that geoengineering by continuous stratospheric injection of SO2 gas may be limited by the growth of the aerosols. We study the efficacy of SO2, H2SO4 and aerosol injections on aerosol mass and optical depth using a three-dimensional general circulation model with sulfur chemistry and sectional aerosol microphysics (WACCM/CARMA. We find increasing injection rates of SO2 in a narrow band around the equator to have limited efficacy while broadening the injecting zone as well as injecting particles instead of SO2 gas increases the sulfate burden for a given injection rate, in agreement with previous work. We find that injecting H2SO4 gas instead of SO2 does not discernibly alter sulfate size or mass, in contrast with a previous study using a plume model with a microphysical model. However, the physics and chemistry in aircraft plumes, which are smaller than climate model grid cells, need to be more carefully considered. We find equatorial injections increase aerosol optical depth in the Northern Hemisphere more than the Southern Hemisphere, potentially inducing regional climate changes. We also find significant perturbations to tropospheric aerosol for all injections studied, particularly in the upper troposphere and near the poles, where sulfate burden increases by up to 100 times. This enhanced burden could have implications for tropospheric radiative forcing and chemistry. These results highlight the need to mitigate greenhouse gas emissions through means other than geoengineering, and to further study geoengineering before it can be seriously considered as a climate intervention option.

  7. Microphysical simulations of sulfur burdens from stratospheric sulfur geoengineering

    Directory of Open Access Journals (Sweden)

    J. M. English

    2012-05-01

    Full Text Available Recent microphysical studies suggest that geoengineering by continuous stratospheric injection of SO2 gas may be limited by the growth of the aerosols. We study the efficacy of SO2, H2SO4 and aerosol injections on aerosol mass and optical depth using a three-dimensional general circulation model with sulfur chemistry and sectional aerosol microphysics (WACCM/CARMA. We find increasing injection rates of SO2 in a narrow band around the equator to have limited efficacy while broadening the injecting zone as well as injecting particles instead of SO2 gas increases the sulfate burden for a given injection rate, in agreement with previous work. We find that injecting H2SO4 gas instead of SO2 does not discernibly alter sulfate size or mass, in contrast with a previous study using a plume model with a microphysical model. However, the physics and chemistry in aircraft plumes, which are smaller than climate model grid cells, need to be more carefully considered. We also find significant perturbations to tropospheric aerosol for all injections studied, particularly in the upper troposphere and near the poles, where sulfate burden increases by up to 100 times. This enhanced burden could have implications for tropospheric radiative forcing and chemistry. These results highlight the need to mitigate greenhouse gas emissions rather than attempt to cool the planet through geoengineering, and to further study geoengineering before it can be seriously considered as a climate intervention option.

  8. Predatory prokaryotes: predation and primary consumption evolved in bacteria

    Science.gov (United States)

    Guerrero, R.; Pedros-Alio, C.; Esteve, I.; Mas, J.; Chase, D.; Margulis, L.

    1986-01-01

    Two kinds of predatory bacteria have been observed and characterized by light and electron microscopy in samples from freshwater sulfurous lakes in northeastern Spain. The first bacterium, named Vampirococcus, is Gram-negative and ovoidal (0.6 micrometer wide). An anaerobic epibiont, it adheres to the surface of phototrophic bacteria (Chromatium spp.) by specific attachment structures and, as it grows and divides by fission, destroys its prey. An important in situ predatory role can be inferred for Vampirococcus from direct counts in natural samples. The second bacterium, named Daptobacter, is a Gram-negative, facultatively anaerobic straight rod (0.5 x 1.5 micrometers) with a single polar flagellum, which collides, penetrates, and grows inside the cytoplasm of its prey (several genera of Chromatiaceae). Considering also the well-known case of Bdellovibrio, a Gram-negative, aerobic curved rod that penetrates and divides in the periplasmic space of many chemotrophic Gram-negative bacteria, there are three types of predatory prokaryotes presently known (epibiotic, cytoplasmic, and periplasmic). Thus, we conclude that antagonistic relationships such as primary consumption, predation, and scavenging had already evolved in microbial ecosystems prior to the appearance of eukaryotes. Furthermore, because they represent methods by which prokaryotes can penetrate other prokaryotes in the absence of phagocytosis, these associations can be considered preadaptation for the origin of intracellular organelles.

  9. Customers’ Intention to Use Green Products: the Impact of Green Brand Dimensions and Green Perceived Value

    Directory of Open Access Journals (Sweden)

    Doszhanov Aibek

    2015-01-01

    Full Text Available This study aimed to identify the relationships between green brand dimension (green brand awareness, green brand image, and green brand trust, green perceived value and customer’s intention to use green products. Data was collected through structured survey questionnaire from 384 customers of three hypermarkets in Kuala-Lumpur. Data was analyzed based on multiple regression analysis. The results indicate that there are significant relationships between green brand awareness, green brand trust, green perceived value, and customer’s intention to use green products. However, green brand image was not found to have significant relationship with customer’s intention to use green products. The discussion presented suggestions for marketers and researchers interested in green branding.

  10. Interactions between diatoms and bacteria.

    Science.gov (United States)

    Amin, Shady A; Parker, Micaela S; Armbrust, E Virginia

    2012-09-01

    Diatoms and bacteria have cooccurred in common habitats for hundreds of millions of years, thus fostering specific associations and interactions with global biogeochemical consequences. Diatoms are responsible for one-fifth of the photosynthesis on Earth, while bacteria remineralize a large portion of this fixed carbon in the oceans. Through their coexistence, diatoms and bacteria cycle nutrients between oxidized and reduced states, impacting bioavailability and ultimately feeding higher trophic levels. Here we present an overview of how diatoms and bacteria interact and the implications of these interactions. We emphasize that heterotrophic bacteria in the oceans that are consistently associated with diatoms are confined to two phyla. These consistent bacterial associations result from encounter mechanisms that occur within a microscale environment surrounding a diatom cell. We review signaling mechanisms that occur in this microenvironment to pave the way for specific interactions. Finally, we discuss known interactions between diatoms and bacteria and exciting new directions and research opportunities in this field. Throughout the review, we emphasize new technological advances that will help in the discovery of new interactions. Deciphering the languages of diatoms and bacteria and how they interact will inform our understanding of the role these organisms have in shaping the ocean and how these interactions may change in future oceans. PMID:22933565

  11. Interactions between Diatoms and Bacteria

    Science.gov (United States)

    Amin, Shady A.; Parker, Micaela S.

    2012-01-01

    Summary: Diatoms and bacteria have cooccurred in common habitats for hundreds of millions of years, thus fostering specific associations and interactions with global biogeochemical consequences. Diatoms are responsible for one-fifth of the photosynthesis on Earth, while bacteria remineralize a large portion of this fixed carbon in the oceans. Through their coexistence, diatoms and bacteria cycle nutrients between oxidized and reduced states, impacting bioavailability and ultimately feeding higher trophic levels. Here we present an overview of how diatoms and bacteria interact and the implications of these interactions. We emphasize that heterotrophic bacteria in the oceans that are consistently associated with diatoms are confined to two phyla. These consistent bacterial associations result from encounter mechanisms that occur within a microscale environment surrounding a diatom cell. We review signaling mechanisms that occur in this microenvironment to pave the way for specific interactions. Finally, we discuss known interactions between diatoms and bacteria and exciting new directions and research opportunities in this field. Throughout the review, we emphasize new technological advances that will help in the discovery of new interactions. Deciphering the languages of diatoms and bacteria and how they interact will inform our understanding of the role these organisms have in shaping the ocean and how these interactions may change in future oceans. PMID:22933565

  12. Metal-Sulfur Battery Cathodes Based on PAN-Sulfur Composites.

    Science.gov (United States)

    Wei, Shuya; Ma, Lin; Hendrickson, Kenville E; Tu, Zhengyuan; Archer, Lynden A

    2015-09-23

    Sulfur/polyacrylonitrile composites provide a promising route toward cathode materials that overcome multiple, stubborn technical barriers to high-energy, rechargeable lithium-sulfur (Li-S) cells. Using a facile thermal synthesis procedure in which sulfur and polyacrylonitrile (PAN) are the only reactants, we create a family of sulfur/PAN (SPAN) nanocomposites in which sulfur is maintained as S3/S2 during all stages of the redox process. By entrapping these smaller molecular sulfur species in the cathode through covalent bonding to and physical confinement in a conductive host, these materials are shown to completely eliminate polysulfide dissolution and shuttling between lithium anode and sulfur cathode. We also show that, in the absence of any of the usual salt additives required to stabilize the anode in traditional Li-S cells, Li-SPAN cells cycle trouble free and at high Coulombic efficiencies in simple carbonate electrolytes. Electrochemical and spectroscopic analysis of the SPAN cathodes at various stages of charge and discharge further show a full and reversible reduction and oxidation between elemental sulfur and Li-ions in the electrolyte to produce Li2S as the only discharge product over hundreds of cycles of charge and discharge at fixed current densities. PMID:26325146

  13. Infiltrating sulfur into a highly porous carbon sphere as cathode material for lithium–sulfur batteries

    International Nuclear Information System (INIS)

    Highlights: • A highly porous carbon (HPC) with regular spherical morphology was synthesized. • Sulfur/HPC composites were prepared by melt–diffusion method. • Sulfur/HPC composites showed improved cyclablity and long-term cycle life. - Abstract: Sulfur composite material with a highly porous carbon sphere as the conducting container was prepared. The highly porous carbon sphere was easily synthesized with resorcinol–formaldehyde precursor as the carbon source. The morphology of the carbon was observed with field emission scanning electron microscope and transmission electron microscope, which showed a well-defined spherical shape. Brunauer–Emmett–Teller analysis indicated that it possesses a high specific surface area of 1563 m2 g?1 and a total pore volume of 2.66 cm3 g?1 with a bimodal pore size distribution, which allow high sulfur loading and easy transportation of lithium ions. Sulfur carbon composites with varied sulfur contents were prepared by melt–diffusion method and lithium sulfur cells with the sulfur composites showed improved cyclablity and long-term cycle life

  14. Green Chemistry and Education.

    Science.gov (United States)

    Hjeresen, Dennis L.; Schutt, David L.; Boese, Janet M.

    2000-01-01

    Many students today are profoundly interested in the sustainability of their world. Introduces Green Chemistry and its principles with teaching materials. Green Chemistry is the use of chemistry for pollution prevention and the design of chemical products and processes that are environmentally benign. (ASK)

  15. Green by Default

    DEFF Research Database (Denmark)

    Sunstein, Cass R.; Reisch, Lucia

    2013-01-01

    The article offers information on the two sources of energy including green energy and gray energy. It discusses several facts which includes lower levels of greenhouse gases and conventional pollutants, relationship between economic incentives and underlying preferences and potential effects of green default rules..

  16. Greening the Future

    Science.gov (United States)

    Williamson, Norma Velia

    2011-01-01

    Because educators vicariously touch the future through their students, the author believes that they sometimes have the uncanny ability to see the future. One common future forecast is the phenomenal growth of green jobs in the emerging green economy, leading to the creation of the "Reach of the Sun" Solar Energy Academy at La Mirada High School…

  17. Direct Observation of Sulfur Radicals as Reaction Media in lithium Sulfur Batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qiang; Zheng, Jianming; Walter, Eric D.; Pan, Huilin; Lu, Dongping; Zuo, Pengjian; Chen, Honghao; Deng, Zhiqun; Liaw, Bor Yann; Yu, Xiqian; Yang, Xiaoning; Zhang, Jiguang; Liu, Jun; Xiao, Jie

    2014-12-09

    Lithium sulfur (Li-S) battery has been regaining tremendous interest in recent years because of its attractive attributes such as high gravimetric energy, low cost and environmental benignity. However, it is still not conclusively known how polysulfide ring/chain participates in the whole cycling and whether the discharge and charge process follow the same pathway. Herein, we demonstrate the direct observation of sulfur radicals by using in situ electron paramagnetic resonance (EPR) technique. Based on the concentration changes of sulfur radicals at different potentials, it is revealed that the chemical and electrochemical reactions in Li-S cell are driven each other to proceed through sulfur radicals, leading to two completely different reaction pathways during discharge and charge. The proposed radical mechanism may provide new insights to investigate the interactions between sulfur species and the electrolyte, inspiring novel strategies to develop Li-S battery technology.

  18. On Maximal Green Sequences

    CERN Document Server

    Brüstle, Thomas; Pérotin, Matthieu

    2012-01-01

    Maximal green sequences are particular sequences of quiver mutations which were introduced by Keller in the context of quantum dilogarithm identities and independently by Cecotti-Cordova-Vafa in the context of supersymmetric gauge theory. Our aim is to initiate a systematic study of these sequences from a combinatorial point of view. Interpreting maximal green sequences as paths in various natural posets arising in representation theory, we prove the finiteness of the number of maximal green sequences for cluster finite quivers, affine quivers and acyclic quivers with at most three vertices. We also give results concerning the possible numbers and lengths of these maximal green sequences. Finally we describe an algorithm for computing maximal green sequences for arbitrary valued quivers which we used to obtain numerous explicit examples that we present.

  19. Green Valley Galaxies

    CERN Document Server

    Salim, Samir

    2015-01-01

    The "green valley" is a wide region separating the blue and the red peaks in the ultraviolet-optical color magnitude diagram, first revealed using GALEX UV photometry. The term was coined by Christopher Martin in 2005. Green valley highlights the discriminating power of UV to very low relative levels of ongoing star formation, to which the optical colors, including u-r, are insensitive. It corresponds to massive galaxies below the star-forming "main" sequence, and therefore represents a critical tool for the study of the quenching of star formation and its possible resurgence in otherwise quiescent galaxies. This article reviews the results pertaining to morphology, structure, environment, dust content and gas properties of green valley galaxies in the local universe. Their relationship to AGN is also discussed. Attention is given to biases emerging from defining the "green valley" using optical colors. We review various evolutionary scenarios and we present evidence for a new, quasi-static view of the green ...

  20. Biharmonic Green functions

    Directory of Open Access Journals (Sweden)

    Heinrich Begehr

    2006-11-01

    Full Text Available The harmonic Green and Neumann function and a particular Robin function are used to construct bi-harmonic Green, Neumann and particular Robin functions. Moreover hybrid bi-harmonic Green functions are given. They all are constructed via a convolution of the mentioned harmonic particular fundamental solutions. In case of the unit disc they are explicitly expressed. Besides these 9 bi-harmonic Green functions there is another bi-harmonic Green function in explicit form for the unit disc not defined by convolution. Related boundary value problems are not all well posed. In case they are, the unique solutions are given. For the other cases solvability conditions are determined and the unique solutions found. There are all together 12 Dirichlet kind boundary value problems for the inhomogeneous bi-harmonic equation treated. The investigation is restricted to the two dimensional case and complex notation is used.

  1. Sulfur vesicles from Thermococcales: A possible role in sulfur detoxifying mechanisms.

    Science.gov (United States)

    Gorlas, A; Marguet, E; Gill, S; Geslin, C; Guigner, J-M; Guyot, F; Forterre, P

    2015-11-01

    The euryarchaeon Thermococcus prieurii inhabits deep-sea hydrothermal vents, one of the most extreme environments on Earth, which is reduced and enriched with heavy metals. Transmission electron microscopy and cryo-electron microscopy imaging of T. prieurii revealed the production of a plethora of diverse membrane vesicles (MVs) (from 50 nm to 400 nm), as is the case for other Thermococcales. T. prieurii also produces particularly long nanopods/nanotubes, some of them containing more than 35 vesicles encased in a S-layer coat. Notably, cryo-electron microscopy of T. prieurii cells revealed the presence of numerous intracellular dark vesicles that bud from the host cells via interaction with the cytoplasmic membrane. These dark vesicles are exclusively found in conjunction with T. prieurii cells and never observed in the purified membrane vesicles preparations. Energy-Dispersive-X-Ray analyses revealed that these dark vesicles are filled with sulfur. Furthermore, the presence of these sulfur vesicles (SVs) is exclusively observed when elemental sulfur was added into the growth medium. In this report, we suggest that these atypical vesicles sequester the excess sulfur not used for growth, thus preventing the accumulation of toxic levels of sulfur in the host's cytoplasm. These SVs transport elemental sulfur out of the cell where they are rapidly degraded. Intriguingly, closely related archaeal species, Thermococcus nautili and Thermococcus kodakaraensis, show some differences about the production of sulfur vesicles. Whereas T. kodakaraensis produces less sulfur vesicles than T. prieurii, T. nautili does not produce such sulfur vesicles, suggesting that Thermococcales species exhibit significant differences in their sulfur metabolic pathways. PMID:26234734

  2. Sulfur vesicles from Thermococcales: A possible role in sulfur detoxifying mechanisms

    Science.gov (United States)

    Gorlas, A.; Marguet, E.; Gill, S.; Geslin, C.; Guigner, J.-M.; Guyot, F.; Forterre, P.

    2015-01-01

    The euryarchaeon Thermococcus prieurii inhabits deep-sea hydrothermal vents, one of the most extreme environments on Earth, which is reduced and enriched with heavy metals. Transmission electron microscopy and cryo-electron microscopy imaging of T. prieurii revealed the production of a plethora of diverse membrane vesicles (MVs) (from 50 nm to 400 nm), as is the case for other Thermococcales. T. prieurii also produces particularly long nanopods/nanotubes, some of them containing more than 35 vesicles encased in a S-layer coat. Notably, cryo-electron microscopy of T. prieurii cells revealed the presence of numerous intracellular dark vesicles that bud from the host cells via interaction with the cytoplasmic membrane. These dark vesicles are exclusively found in conjunction with T. prieurii cells and never observed in the purified membrane vesicles preparations. Energy-Dispersive-X-Ray analyses revealed that these dark vesicles are filled with sulfur. Furthermore, the presence of these sulfur vesicles (SVs) is exclusively observed when elemental sulfur was added into the growth medium. In this report, we suggest that these atypical vesicles sequester the excess sulfur not used for growth, thus preventing the accumulation of toxic levels of sulfur in the host's cytoplasm. These SVs transport elemental sulfur out of the cell where they are rapidly degraded. Intriguingly, closely related archaeal species, Thermococcus nautili and Thermococcus kodakaraensis, show some differences about the production of sulfur vesicles. Whereas T. kodakaraensis produces less sulfur vesicles than T. prieurii, T. nautili does not produce such sulfur vesicles, suggesting that Thermococcales species exhibit significant differences in their sulfur metabolic pathways. PMID:26234734

  3. Sulfur 'Concrete' for Lunar Applications - Environmental Considerations

    Science.gov (United States)

    Grugel, R. N.

    2008-01-01

    Commercial use of sulfur concrete on Earth is well established, particularly in corrosive, e.g., acid and salt, environments. Having found troilite (FeS) on the Moon raises the question of using extracted sulfur as a lunar construction material, an attractive alternative to conventional concrete as it does not require water. For the purpose of this Technical Memorandum, it is assumed that lunar ore is mined, refined, and the raw sulfur processed with appropriate lunar regolith to form, for example, bricks. With this stipulation, it is then noted that the viability of sulfur concrete in a lunar environment, which is characterized by lack of an atmosphere and extreme temperatures, is not well understood. The work presented here evaluates two sets of small sulfur concrete samples that have been prepared using JSC-1 lunar simulant as an aggregate addition. One set was subjected to extended periods in high vacuum to evaluate sublimation issues, and the other was cycled between room and liquid nitrogen temperatures to investigate their subsequent mechanical integrity. Results are presented from both investigations, discussed, and put into the context of the lunar environment.

  4. Digestion of Bangka monazite with sulfuric acid

    International Nuclear Information System (INIS)

    Technology of Bangka monazite processing with alkaline method has been mastered by PPGN BATAN with the product in the form of RE (Rare Earth) which is contain U < 2 ppm and Th 12 - 16 ppm. Hence, as comparator, the research of Bangka monazite processing with acid method using sulfuric acid has been done. The aim of this research is to obtain the optimal condition of Bangka monazite's digestion using sulfuric acid so that all elements contained in the monazite that are U, Th, RE, PO4 dissolved as much as possible. The research parameter's arc monazite particle's size, sulfuric acid consumption (weight ratio of monazite ore : sulfuric acid), digestion temperature, digestion time and consumption of wash water. The results showed that the optimal conditions of digestion are 250+ 325 mesh of monazite particle's size, 1 : 2.5 of weight ratio of monazite ore: sulfuric acid, 190°C of digestion temperature, 3 hours of digestion time and 8 times of weight monazite's feed of wash water with the recovery of digested U = 99.90 %, Th = 99.44 %, RE = 98.64 % and PO4 = 99.88 %. (author)

  5. An Aerosol Condensation Model for Sulfur Trioxide

    Energy Technology Data Exchange (ETDEWEB)

    Grant, K E

    2008-02-07

    This document describes a model for condensation of sulfuric acid aerosol given an initial concentration and/or source of gaseous sulfur trioxide (e.g. fuming from oleum). The model includes the thermochemical effects on aerosol condensation and air parcel buoyancy. Condensation is assumed to occur heterogeneously onto a preexisting background aerosol distribution. The model development is both a revisiting of research initially presented at the Fall 2001 American Geophysical Union Meeting [1] and a further extension to provide new capabilities for current atmospheric dispersion modeling efforts [2]. Sulfuric acid is one of the most widely used of all industrial chemicals. In 1992, world consumption of sulfuric acid was 145 million metric tons, with 42.4 Mt (mega-tons) consumed in the United States [10]. In 2001, of 37.5 Mt consumed in the U.S., 74% went into producing phosphate fertilizers [11]. Another significant use is in mining industries. Lawuyi and Fingas [7] estimate that, in 1996, 68% of use was for fertilizers and 5.8% was for mining. They note that H{sub 2}SO{sub 4} use has been and should continue to be very stable. In the United States, the elimination of MTBE (methyl tertiary-butyl ether) and the use of ethanol for gasoline production are further increasing the demand for petroleum alkylate. Alkylate producers have a choice of either a hydrofluoric acid or sulfuric acid process. Both processes are widely used today. Concerns, however, over the safety or potential regulation of hydrofluoric acid are likely to result in most of the growth being for the sulfuric acid process, further increasing demand [11]. The implication of sulfuric acid being a pervasive industrial chemical is that transport is also pervasive. Often, this is in the form of oleum tankers, having around 30% free sulfur trioxide. Although sulfuric acid itself is not a volatile substance, fuming sulfuric acid (referred to as oleum) is [7], the volatile product being sulfur trioxide. Sulfate aerosols and mist may form in the atmosphere on tank rupture. From chemical spill data from 1990-1996, Lawuyi02 and Fingas [7] prioritize sulfuric acid as sixth most serious. During this period, they note 155 spills totaling 13 Mt, out of a supply volume of 3700 Mt. Lawuyi and Fingas [7] summarize information on three major sulfuric acid spills. On 12 February 1984, 93 tons of sulfuric acid were spilled when 14 railroad cars derailed near MacTier, Parry Sound, Ontario. On 13 December 1978, 51 railroad cars derailed near Springhill, Nova Scotia. One car, containing 93% sulfuric acid, ruptured, spilling nearly its entire contents. In July 1993, 20 to 50 tons of fuming sulfuric acid spilled at the General Chemical Corp. plant in Richmond, California, a major industrial center near San Francisco. The release occurred when oleum was being loaded into a nonfuming acid railroad tank car that contained only a rupture disk as a safety device. The tank car was overheated and this rupture disk blew. The resulting cloud of sulfuric acid drifted northeast with prevailing winds over a number of populated areas. More than 3,000 people subsequently sought medical attention for burning eyes, coughing, headaches, and nausea. Almost all were treated and released on the day of the spill. By the day after the release, another 5,000 people had sought medical attention. The spill forced the closure of five freeways in the region as well as some Bay Area Rapid Transit System stations. Apart from corrosive toxicity, there is the additional hazard that the reactions of sulfur trioxide and sulfuric acid vapors with water are extremely exothermic [10, 11]. While the vapors are intrinsically denser than air, there is thus the likelihood of strong, warming-induced buoyancy from reactions with ambient water vapor, water-containing aerosol droplets, and wet environmental surface. Nordin [12] relates just such an occurrence following the Richmond, CA spill, with the plume observed to rise to 300 m. For all practical purposes, sulfur trioxide was the constituent released from the heated tank

  6. Lithium-sulfur batteries: progress and prospects.

    Science.gov (United States)

    Manthiram, Arumugam; Chung, Sheng-Heng; Zu, Chenxi

    2015-03-25

    Development of advanced energy-storage systems for portable devices, electric vehicles, and grid storage must fulfill several requirements: low-cost, long life, acceptable safety, high energy, high power, and environmental benignity. With these requirements, lithium-sulfur (Li-S) batteries promise great potential to be the next-generation high-energy system. However, the practicality of Li-S technology is hindered by technical obstacles, such as short shelf and cycle life and low sulfur content/loading, arising from the shuttling of polysulfide intermediates between the cathode and anode and the poor electronic conductivity of S and the discharge product Li2 S. Much progress has been made during the past five years to circumvent these problems by employing sulfur-carbon or sulfur-polymer composite cathodes, novel cell configurations, and lithium-metal anode stabilization. This Progress Report highlights recent developments with special attention toward innovation in sulfur-encapsulation techniques, development of novel materials, and cell-component design. The scientific understanding and engineering concerns are discussed at the end in every developmental stage. The critical research directions needed and the remaining challenges to be addressed are summarized in the Conclusion. PMID:25688969

  7. Sulfur sources in protein supplements for ruminants

    Scientific Electronic Library Online (English)

    Cássio José da, Silva; Fernando de Paula, Leonel; José Carlos, Pereira; Marcone Geraldo, Costa; Leonardo Marmo, Moreira; Tadeu Silva de, Oliveira; Claudilene Lima de, Abreu.

    2014-10-01

    Full Text Available The present study evaluates the efficiency of different sulfur sources for ruminant nutrition. The fiber digestibility and the amino acid profile were analyzed in the duodenal digesta of crossbred steers fed Brachiaria dictyoneura hay. The sources utilized were elemental sulfur (ES70S), elemental su [...] lfur (ES98S); calcium sulfate in hydrated (HCS), CaSO4.2H2O, and anhydrous (ACS), CaSO4, forms; and ammonium sulfate (AS), (NH4)2SO4, keeping a nitrogen:sulfur ratio of 11:1. The iso-protein supplements had 50% of protein in the total dry matter (DM). Five Holstein × Zebu steers, which were fistulated in the rumen and abomasum, were distributed in a 5 × 5 Latin square. The different sulfur sources in the supplement did not affect any of the evaluated nutritional factors, such as intake of hay dry matter and protein supplement, crude protein (CP), neutral detergent fiber corrected for ash and protein (NDFap), organic matter (OM), non-fibrous carbohydrate (NFC), ether extract (EE), total digestible nutrients (TDN), NDFap and CP digestibility coefficients, ruminal pH, and ruminal ammonia concentration. The concentrations of amino acids available in the abomasal digesta did not differ significantly in the tested diets. The sulfur sources evaluated in the present study are suitable as supplement for cattle, and their employment may be important to avoid environmental contaminations.

  8. Superoxide dismutase in ruminal bacteria.

    OpenAIRE

    Fulghum, R S; Worthington, J M

    1984-01-01

    Of 13 species of anaerobic ruminal bacteria examined, 11 were found to contain measurable levels of superoxide dismutase activity. Four of five other strict anaerobic species studied for comparison were found to contain superoxide dismutase activity.

  9. Chitin Degradation In Marine Bacteria

    DEFF Research Database (Denmark)

    Paulsen, Sara; Machado, Henrique; Gram, Lone

    2015-01-01

    Introduction: Chitin is the most abundant polymer in the marine environment and the second most abundant in nature. Chitin does not accumulate on the ocean floor, because of microbial breakdown. Chitin degrading bacteria could have potential in the utilization of chitin as a renewable carbon and nitrogen source in the fermentation industry.Methods: Here, whole genome sequenced marine bacteria were screened for chitin degradation using phenotypic and in silico analyses.Results: The in silico anal...

  10. Thymidine kinase diversity in bacteria

    DEFF Research Database (Denmark)

    Sandrini, Michael; Clausen, A.R.; Munch-Petersen, B.; Piskur, Jure

    2006-01-01

    Thymidine kinases (TKs) appear to be almost ubiquitous and are found in nearly all prokaryotes, eukaryotes, and several viruses. They are the key enzymes in thymidine salvage and activation of several anti-cancer and antiviral drugs. We show that bacterial TKs can be subdivided into 2 groups. The TKs from Gram-positive bacteria are more closely related to the eukaryotic TK1 enzymes than are TKs from Gram-negative bacteria.

  11. Immunomodulatory properties of probiotic bacteria

    DEFF Research Database (Denmark)

    Fink, Lisbeth Nielsen

    2007-01-01

    Certain lactic acid bacteria (LAB) are part of the commensal intestinal flora and considered beneficial for health, as they compete with pathogens for adhesion sites in the intestine and ferment otherwise indigestible compounds. Another important property of these so-called probiotic bacteria is the ability to modulate the immune response. This thesis describes the immunomodulatory properties of gut-derived bacterial strains on different antigen-presenting cells, and the effector cell responses ...

  12. Money and transmission of bacteria

    OpenAIRE

    Gedik, Habip; Voss, Timothy A; Voss, Andreas

    2013-01-01

    Money is one of the most frequently passed items in the world. The aim of this study was to ascertain the survival status of bacteria including Staphylococcus aureus, Escherichia coli, and Vancomycin- Resistant Enterococci (VRE) on banknotes from different countries and the transmission of bacteria to people who come in contact with the banknotes. The survival rate was highest for the Romanian Leu yielding all three microorganisms used after both three and six hours of drying. Furthermore, th...

  13. The mechanical world of bacteria.

    Science.gov (United States)

    Persat, Alexandre; Nadell, Carey D; Kim, Minyoung Kevin; Ingremeau, Francois; Siryaporn, Albert; Drescher, Knut; Wingreen, Ned S; Bassler, Bonnie L; Gitai, Zemer; Stone, Howard A

    2015-05-21

    In the wild, bacteria are predominantly associated with surfaces as opposed to existing as free-swimming, isolated organisms. They are thus subject to surface-specific mechanics, including hydrodynamic forces, adhesive forces, the rheology of their surroundings, and transport rules that define their encounters with nutrients and signaling molecules. Here, we highlight the effects of mechanics on bacterial behaviors on surfaces at multiple length scales, from single bacteria to the development of multicellular bacterial communities such as biofilms. PMID:26000479

  14. Cryptic carbon and sulfur cycling between surface ocean plankton.

    Science.gov (United States)

    Durham, Bryndan P; Sharma, Shalabh; Luo, Haiwei; Smith, Christa B; Amin, Shady A; Bender, Sara J; Dearth, Stephen P; Van Mooy, Benjamin A S; Campagna, Shawn R; Kujawinski, Elizabeth B; Armbrust, E Virginia; Moran, Mary Ann

    2015-01-13

    About half the carbon fixed by phytoplankton in the ocean is taken up and metabolized by marine bacteria, a transfer that is mediated through the seawater dissolved organic carbon (DOC) pool. The chemical complexity of marine DOC, along with a poor understanding of which compounds form the basis of trophic interactions between bacteria and phytoplankton, have impeded efforts to identify key currencies of this carbon cycle link. Here, we used transcriptional patterns in a bacterial-diatom model system based on vitamin B12 auxotrophy as a sensitive assay for metabolite exchange between marine plankton. The most highly up-regulated genes (up to 374-fold) by a marine Roseobacter clade bacterium when cocultured with the diatom Thalassiosira pseudonana were those encoding the transport and catabolism of 2,3-dihydroxypropane-1-sulfonate (DHPS). This compound has no currently recognized role in the marine microbial food web. As the genes for DHPS catabolism have limited distribution among bacterial taxa, T. pseudonana may use this sulfonate for targeted feeding of beneficial associates. Indeed, DHPS was both a major component of the T. pseudonana cytosol and an abundant microbial metabolite in a diatom bloom in the eastern North Pacific Ocean. Moreover, transcript analysis of the North Pacific samples provided evidence of DHPS catabolism by Roseobacter populations. Other such biogeochemically important metabolites may be common in the ocean but difficult to discriminate against the complex chemical background of seawater. Bacterial transformation of this diatom-derived sulfonate represents a previously unidentified and likely sizeable link in both the marine carbon and sulfur cycles. PMID:25548163

  15. Cable Bacteria in Freshwater Sediments

    DEFF Research Database (Denmark)

    Risgaard-Petersen, Nils; Kristiansen, Michael

    2015-01-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures and electric fields indicated electron transfer between vertically separated anodic and cathodic half-reactions. Fluorescence in situ hybridization revealed the presence of Desulfobulbaceae filaments. In addition, in situ measurements of oxygen, pH, and electric potential distributions in the waterlogged banks of Giber Å demonstrated the presence of distant electric redox coupling in naturally occurring freshwater sediment. At the same site, filamentous Desulfobulbaceae with cable bacterium morphology were found to be present. Their 16S rRNA gene sequence placed them as a distinct sister group to the known marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary origin of the cable phenotype within Desulfobulbaceae with subsequent diversification into a freshwater and a marine lineage.

  16. Filtrating forms of soil bacteria

    Science.gov (United States)

    Van'kova, A. A.; Ivanov, P. I.; Emtsev, V. T.

    2013-03-01

    Filtrating (ultramicroscopic) forms (FF) of bacteria were studied in a soddy-podzolic soil and the root zone of alfalfa plants as part of populations of the most widespread physiological groups of soil bacteria. FF were obtained by filtering soil solutions through membrane filters with a pore diameter of 0.22 ?m. It was established that the greater part of the bacteria in the soil and in the root zone of the plants has an ultramicroscopic size: the average diameter of the cells is 0.3 ?m, and their length is 0.6 ?m, which is significantly less than the cell size of banal bacteria. The number of FF varies within a wide range depending on the physicochemical conditions of the habitat. The FF number's dynamics in the soil is of a seasonal nature; i.e., the number of bacteria found increases in the summer and fall and decreases in the winter-spring period. In the rhizosphere of the alfalfa, over the vegetation period, the number of FF and their fraction in the total mass of the bacteria increase. A reverse tendency is observed in the rhizoplane. The morphological particularities (identified by an electron microscopy) and the nature of the FF indicate their physiological activity.

  17. Cable Bacteria in Freshwater Sediments.

    Science.gov (United States)

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus B; Dittmer, Anders Lindequist; Bjerg, Jesper Tataru; Trojan, Daniela; Schreiber, Lars; Damgaard, Lars Riis; Schramm, Andreas; Nielsen, Lars Peter

    2015-09-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures and electric fields indicated electron transfer between vertically separated anodic and cathodic half-reactions. Fluorescence in situ hybridization revealed the presence of Desulfobulbaceae filaments. In addition, in situ measurements of oxygen, pH, and electric potential distributions in the waterlogged banks of Giber Å demonstrated the presence of distant electric redox coupling in naturally occurring freshwater sediment. At the same site, filamentous Desulfobulbaceae with cable bacterium morphology were found to be present. Their 16S rRNA gene sequence placed them as a distinct sister group to the known marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary origin of the cable phenotype within Desulfobulbaceae with subsequent diversification into a freshwater and a marine lineage. PMID:26116678

  18. Bioreporter bacteria for landmine detection

    Energy Technology Data Exchange (ETDEWEB)

    Burlage, R.S. [Oak Ridge National Lab., TN (United States); Youngblood, T. [Frisby Technologies, Aiken, SC (United States); Lamothe, D. [American Technologies, Inc., Huntsville, AL (United States). Ordnance/Explosives Environmental Services Div.

    1998-04-01

    Landmines (and other UXO) gradually leak explosive chemicals into the soil at significant concentrations. Bacteria, which have adapted to scavenge low concentrations of nutrients, can detect these explosive chemicals. Uptake of these chemicals results in the triggering of specific bacterial genes. The authors have created genetically recombinant bioreporter bacteria that detect small concentrations of energetic chemicals. These bacteria are genetically engineered to produce a bioluminescent signal when they contact specific explosives. A gene for a brightly fluorescent compound can be substituted for increased sensitivity. By finding the fluorescent bacteria, you find the landmine. Detection might be accomplished using stand-off illumination of the minefield and GPS technology, which would result in greatly reduced risk to the deminers. Bioreporter technology has been proven at the laboratory scale, and will be tested under field conditions in the near future. They have created a bacterial strain that detects sub-micromolar concentrations of o- and p-nitrotoluene. Related bacterial strains were produced using standard laboratory protocols, and bioreporters of dinitrotoluene and trinitrotoluene were produced, screening for activity with the explosive compounds. Response time is dependent on the growth rate of the bacteria. Although frill signal production may require several hours, the bacteria can be applied over vast areas and scanned quickly, producing an equivalent detection speed that is very fast. This technology may be applicable to other needs, such as locating buried explosives at military and ordnance/explosive manufacturing facilities.

  19. Green growth in fisheries

    DEFF Research Database (Denmark)

    Nielsen, Max; Ravensbeck, Lars

    2014-01-01

    Climate change and economic growth have gained a substantial amount of attention over the last decade. Hence, in order to unite the two fields of interest, the concept of green growth has evolved. The concept of green growth focuses on how to achieve growth in environment-dependent sectors, without harming the environment. Fishery is an environment-dependent sector and it has been argued that there is no potential for green growth in the sector owing to global overexploitation, leaving no scope for production growth. The purpose of this paper is to explain what green growth is and to develop a conceptual framework. Furthermore, the aim is to show that a large green growth potential actually exists in fisheries and to show how this potential can be achieved. The potential green growth appears as value-added instead of production growth. The potential can be achieved by reducing overcapacity, investing in the rebuilding of fish stocks and a coordinated regulation of marine activities that interact with fisheries. Incentive-based regulation of fisheries that counterbalances services of the ecosystems is an important instrument to achieve green growth.

  20. Anthropogenic sulfur dioxide emissions: 1850–2005

    Directory of Open Access Journals (Sweden)

    S. J. Smith

    2011-02-01

    Full Text Available Sulfur aerosols impact human health, ecosystems, agriculture, and global and regional climate. A new annual estimate of anthropogenic global and regional sulfur dioxide emissions has been constructed spanning the period 1850–2005 using a bottom-up mass balance method, calibrated to country-level inventory data. Global emissions peaked in the early 1970s and decreased until 2000, with an increase in recent years due to increased emissions in China, international shipping, and developing countries in general. An uncertainty analysis was conducted including both random and systemic uncertainties. The overall global uncertainty in sulfur dioxide emissions is relatively small, but regional uncertainties ranged up to 30%. The largest contributors to uncertainty at present are emissions from China and international shipping. Emissions were distributed on a 0.5° grid by sector for use in coordinated climate model experiments.

  1. Reinforced Conductive Confinement of Sulfur for Robust and High-Performance Lithium-Sulfur Batteries.

    Science.gov (United States)

    Lai, Chao; Wu, Zhenzhen; Gu, Xingxing; Wang, Chao; Xi, Kai; Kumar, R Vasant; Zhang, Shanqing

    2015-11-01

    Sulfur is an attractive cathode material in energy storage devices due to its high theoretical capacity of 1672 mAh g(-1). However, practical application of lithium-sulfur (Li-S) batteries can be achieved only when the major barriers, including the shuttling effect of polysulfides (Li2Sx, x = 3-8), significant volume change (?80%), and the resultant rapid deterioration of electrodes, are tackled. Here, we propose an "inside-out" synthesis strategy by mimicking the structure of the pomegranate fruit to achieve conductive confinement of sulfur to address these issues. In the proposed pomegranate-like structure, sulfur and carbon nanotubes composite is encapsulated by the in situ formed amorphous carbon network, which allows the regeneration of electroactive material sulfur and the confinement of the sulfur as well as the lithium polysulfide within the electrical conductive carbon network. Consequently, a highly robust sulfur cathode is obtained, delivering remarkable performance in a Li-S battery. The obtained composite cathode shows a reversible capacity of 691 mAh g(-1) after 200 cycles with impressive cycle stability at the current density of 1600 mA g(-1). PMID:26470838

  2. Confine sulfur in mesoporous metal–organic framework @ reduced graphene oxide for lithium sulfur battery

    International Nuclear Information System (INIS)

    Highlights: • Metal organic framework @ reduced graphene oxide was applied for sulfur cathode. • MIL-101(Cr)@rGO/S composites are synthesized by a facile two-step liquid method. • Cycling stability of MIL-101(Cr)@rGO/S sulfur cathode was improved. -- Abstract: Mesoporous metal organic framework @ reduced graphene oxide (MIL-101(Cr)@rGO) materials have been used as a host material to prepare the multi-composite sulfur cathode through a facile and effective two-step liquid phase method successfully, which is different from the simple MIL-101(Cr)/S mixed preparation method. The successful reduced graphene oxide coating in the MIL-101(Cr)@rGO improve the electronic conductivity of meso-MOFs effectively. The discharge capacity and capacity retention rate of MIL-101(Cr)@rGO/S composite sulfur cathode are as high as 650 mAh g?1 and 66.6% at the 50th cycle at the current density of 335 mA g?1. While the discharge capacity and capacity retention rate of MIL-101(Cr)/S mixed sulfur cathode is 458 mAh g?1 and 37.3%. Test results indicate that the MIL-101(Cr)@rGO is a promising host material for the sulfur cathode in the lithium–sulfur battery applications

  3. Sulfur isotope in nature. Determination of sulfur isotope ratios in coal and petroleum by mass spectrometry

    International Nuclear Information System (INIS)

    Elementary sulfur or in chemical compounds is one of the elements widespread in the earth's crust and biosphere. Its participation in earth's crust amounts to 0.26 % by weight. Measurement of isotope composition of natural samples can deliver many information about origin, creation and transformation ranges of rocks and minerals. Sulfur isotope ratio contained in minerals is variable and for this reason investigation of isotope sulfur composition can deliver useful information about the geochemistry of each component. Therefore in the investigated sample it is necessary to determine not only the content of sulfur but also the isotope composition of each component. Differentiation of contents of sulfur-34 in natural sulfur compounds can reach up to 110 per mile. So large divergences can be explained by a kinetic effect or by bacterial reduction of sulphates. In this report a wide review of the results of investigations of isotope sulfur compositions in coal and petroleum are presented as well as the methods for the preparation of samples for mass spectrometry analysis are proposed. (author)

  4. Sulfur turnover and emissions during storage of cattle slurry : Effects of acidification and sulfur addition

    DEFF Research Database (Denmark)

    Eriksen, JØrgen; Andersen, Astrid J

    2012-01-01

    Slurry acidification using sulfuric acid reduces ammonia emissions but also affects sulfur (S) cycling. Emission of sulfur is a source of malodor and reduces the sulfur fertilizer value of the slurry. We investigated the effect of sulfate and methionine amendments, alone or in combination with acidification, on sulfur transformations in slurry and emissions of volatile sulfur compounds (VSC) during storage of fresh and aged cattle slurry. When pH was lowered to 5.5 it resulted in an almost complete inhibition of sulfate reduction. There was a huge emission of hydrogen sulfide (H2S) with addition of sulfate and methionine (P < 0.01). Methanethiol (MT) was emitted in treatments with addition of methionine, especially when simultaneously acidified (P < 0.01). The large H2S production in the sulfate-amended slurries resulted in little accumulation of MT and dimethyl sulfide (DMS) under neutral conditions, in contrast to acidic conditions where the degradation was inhibited and both MT and DMS accumulated. Based on odor activity values, untreated slurry had little odor development from S compounds, especially the aged slurry. Acidification did not significantly increase odor contribution from any of the compounds in fresh or aged slurry. Generally, addition of a sulfate increased the contribution from H2S dramatically, whereas acidification lowered the H2S contribution but increased that of MT. Thus, acidification of slurry with sulfuric acid may potentially produce more odor from S compounds than untreated slurry.

  5. The signal based relationship between the green seaweed Ulva and its indigenous bacterial community

    OpenAIRE

    Twigg, Matthew

    2013-01-01

    This project has focused on the relationship between the green seaweed Ulva, commonly found in the intertidal zone of the UK coastline and its cognate bacterial community. It has previously been reported that motile Ulva zoospores are attracted to N-Acylhomoserine lactones (AHLs), signalling molecules utilised by Gram-negative bacteria in a density dependent form of cellular communication termed quorum sensing (QS) and produced by several biofilm dwelling species of marine bacteria. The speci...

  6. Human impact on the atmospheric sulfur balance

    Science.gov (United States)

    Rodhe, Henning

    1999-02-01

    The paper reviews the development in our understanding of the atmospheric part of the global sulfur cycle, including the role played by C.-G. Rossby and his colleagues in the 1950s, and presents a brief assessment of the current knowledge. Measurements of the concentrations of sulfur compounds in air, precipitation, ice cores and sea water during the past 25years, together with recent development in three-dimensional tracer transport modeling, have resulted in a reasonably consistent picture of the burdens and fluxes of the main sulfur compounds in the atmosphere. It is clear that man's activities, in particular the burning of fossil fuels, are having a large impact on the atmospheric sulfur balance. Even on a global scale, the man-made emissions of gaseous sulfur compounds are likely to be two to three times as large as the natural sources. In and around the most heavily industrialized regions this ratio exceeds ten over extended areas. Nevertheless, there are several important issues that need to be resolved. Some of these are directly linked to the urgent problem of reducing the uncertainty in the estimate of direct and, in particular, indirect climate forcing due to man-made sulfate aerosols. One such issue is the magnitude of the wet scavenging of SO2 and aerosol sulfate during upward transport into and within the free troposphere in connection with convective and frontal cloud systems which has a decisive influence on the sulfate concentrations in the upper troposphere. Another uncertain process is the rate of oxidation of SO2 in cloud droplets and on aerosol particles. A fundamental question that remains to be answered is to what degree man-made sulfur emissions have increased the number of aerosol particles that can act as cloud condensation nuclei.

  7. Green or golden landscapes

    OpenAIRE

    Ponte e Sousa, Clara; Castro, Maria da Conceição

    2012-01-01

    In Mediterranean urban green spaces the green colour of lawns is the image that marks in the landscape. The Mediterranean gardens were invaded by turfgrass. The same green “carpet” is present in front of the Prado museum in Madrid, in front of the Eiffel Tower in Paris, or in front of the Jerónimos Monastery in Lisbon. However, in the driest climates like the Portuguese as Mediterranean one, the landscape summer colour is golden. Since a long time the anglo-saxonic image of gardens with perfe...

  8. Selling the green dream

    International Nuclear Information System (INIS)

    The article discusses the marketing and sales of energy generated from renewable energy sources. To purchase environmental energy in the USA, the consumer need do no more than tick a box on a sheet of paper. But, it is not just households that opt for green energy: businesses are also willing customers. A factor in the success in selling green energy to big business is that the retail price of wind power can be held constant over periods of several years, whereas fossil fuel prices can fluctuate wildly. Details of sources and sales of the top ten companies selling green energy are given

  9. White is green

    Science.gov (United States)

    Glicksman, Hal

    1998-12-01

    Green is the center of the visible spectrum and the hue to which we are most sensitive. In RGB color, green is 60 percent of white. When we look through a prism at a white square, as Goethe did, we see white between yellow and cyan, just where green appears in the spectrum of Newton. Additional arguments were published previously and appear at www.csulb.edu/-percept, along with the Percept color chart of the hue/value relationships. A new argument, derived from the perception of leaves, is presented here. The Percept color chart transformed into a color wheel is also presented.

  10. Effect of green tea supplementation on the microbiological, antioxidant, and sensory properties of probiotic milks

    OpenAIRE

    Najgebauer-Lejko, Dorota

    2014-01-01

    Green tea and its constituents are known for a wide range of health-promoting properties. They may exert antimicrobial action but without altering lactic acid bacteria. The aim of the present study was to estimate the effect of green tea addition on the selected properties of probiotic milks. Bioyogurts (fermented with ABT-1 coculture of Streptococcus thermophilus, Lactobacillus acidophilus LA-5, Bifidobacterium animalis subsp. lactis BB-12) and acidophilus milks (fermented with pure L. acido...

  11. 40 CFR 52.2525 - Control strategy: Sulfur dioxide.

    Science.gov (United States)

    2010-07-01

    ...2010-07-01 2010-07-01 false Control strategy: Sulfur dioxide. 52.2525 Section 52.2525 Protection of Environment... West Virginia § 52.2525 Control strategy: Sulfur dioxide. (a) The provisions of §...

  12. Total Sulfur Deposition (wet+dry) from the Atmosphere

    Data.gov (United States)

    U.S. Environmental Protection Agency — Sulfur Dioxide (SO2) is emitted primarily as a by-product of coal combustion from power plants. Sulfur Dioxide reacts in the atmosphere to form other chemical such...

  13. Acquisition of useful and high ability genes for acidophilic bacteria; Kosansei saikin ni takai noryoku wo fuyosuru idenshi no kakutoku

    Energy Technology Data Exchange (ETDEWEB)

    Senda, T.; Inoue, C.; Shinbori, Y. [Tohoku University, Sendai (Japan)

    1997-02-01

    This effort aims at the development of high-performance bacteria usable in bio-leaching in metal smelting by acquiring genes capable of realizing such. A method is used of choosing some isolated strains exhibiting high-performance traits and acquiring target genes therefrom by use of genetic engineering. Approximately 200 kinds in the aggregate of acidophilic bacteria are currently available for the study, including isolated iron-oxidizing and sulfur-oxidizing bacteria, standard species acquired for the study, and strains previously isolated by the laboratory. The bacteria are tested with respect to their Fe{sup 2+}-oxidizing rates, sulfur-oxidizing capabilities, and strength to withstand inhibiting substances (Ag{sup +}, Cl{sup -}, Mo{sup 6+}, etc.), which results in the nomination of 8 strains. The study planned to follow includes processes involving the extraction of chromosome DNAs from the 8 strains and their refinement, gene cloning by the Southern hybridization method, determination of their base sequences, determination of the difference between the strains in point of gene expression, and investigations of the relations that the results of these processes bear toward the said high-performance traits. Also under way is a study about the infuence-exerting factors revealed during the evaluation of the abilities of acidphlic bacteria. 2 refs., 2 tabs.

  14. From green architecture to architectural green : Facade versus space

    DEFF Research Database (Denmark)

    Earon, Ofri

    The paper investigates the topic of green architecture from an architectural point of view and not an energy point of view. The purpose of the paper is to establish a debate about the architectural language and spatial characteristics of green architecture. In this light, green becomes an adjective that describes the architectural exclusivity of this particular architecture genre. The adjective green expresses architectural qualities differentiating green architecture from none-green architecture. Currently, adding trees and vegetation to the building’s facade is the main architectural characteristics of green architecture. The paper argues that this greenification of facades is insufficient. The green is only a skin cladding the exterior envelope without having a spatial significance. Through the paper it is proposed to flip the order of words from green architecture to architectural green. Architectural green could signify green architecture with inclusive interrelations between green and space, built andunbuilt, inside and outside. The aim of the term is to reflect a new focus in green architecture – its architectural performance. Ecological issues are not underestimated or ignored, but so far they have overshadowed the architectural potential of green architecture. The paper questions how a green space should perform, look like and function. Two examples are chosen to demonstrate thorough integrations between green and space. The examples are public buildings categorized as pavilions. One is Dutch pavilion at Hannover (MVRDV, 2000). The second is MFO Park (Burckhardt + Partner AG, 2002). By the means of the examples, possible characteristics and performance of architectural green are discussed and evaluated. The paper argues that the notion of green as an architectural quality is not limited to the architecture of pavilions and can be applied in other architectural forms and functions. The paper ends by questioning the potential of architectural green in urbanity.

  15. Toward the green economy: Assessing countries' green power

    OpenAIRE

    Never, Babette

    2013-01-01

    The green power potential of a country is a central factor in the transformation to a green economy. This paper argues that green power will become a decisive factor for global change. Green power combines sustainability, innovation and power into one concept. By merging insights from political science, economics and innovation research, this paper develops a multidimensional, multilevel concept of green power that takes both resources and processes into account. A first empirical assessment ...

  16. Green Turtle Trophic Ecology

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — SWFSC is currently conducting a study of green sea turtle (Chelonia mydas) trophic ecology in the eastern Pacific. Tissue samples and stable carbon and stable...

  17. Green Turtle Critical Habitat

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data represent the critical habitat for green turtle as designated by Federal Register Vol. 63, No. 46701, September 2, 1998, Rules and Regulations.

  18. No More Green Thumbs!

    Science.gov (United States)

    Bland, Judith A.

    1977-01-01

    An alternative method of bacterial spore staining using malachite green is described. This technique is designed to save time and expense by a less messy procedure. Advantages and adaptations of the technique are also given. (MR)

  19. Compliance for Green IT

    CERN Document Server

    Calder, Alan

    2009-01-01

    The growing range of Green IT regulations are challenging more and more organisations to take specific steps to ensure they are in compliance with sometimes complex regulations, ranging from cap & trade requirements through to regulations concerning IT equipment disposal.

  20. Green Office 2015; Green Office 2015

    Energy Technology Data Exchange (ETDEWEB)

    Ubachs, H.J.G. [Imtech, Eindhoven (Netherlands)

    2009-06-15

    The project Green Office 2015 is an integral, sustainable and multiple district development in which urban development, landscape, architecture, indoor and technology are integrated. The participants in this project show that integral design has an added value in comparison to a traditional design process. They want to enrich the building and building services sector with their shared knowledge and expertise on sustainable office buildings. [Dutch] Dit artikel beschrijft Het Green Office 2015 project: een integrale, duurzame en meervoudige gebiedsontwikkeling waarin stedenbouw, landschap, architectuur, interieur en technologie samengaan. Met dit project willen de participanten aantonen dat integraal ontwerpen meerwaarde oplevert ten opzichte van de traditionele manier van werken. Alle partijen willen ook, met hun gezamenlijke kennis en expertise, de bouw- en installatiesector verrijken met ideeen voor duurzame kantoorgebouwen.

  1. Sulfur and Nitrogen Co-Doped Graphene for Metal-Free Catalytic Oxidation Reactions.

    Science.gov (United States)

    Duan, Xiaoguang; O'Donnell, Kane; Sun, Hongqi; Wang, Yuxian; Wang, Shaobin

    2015-07-01

    Sulfur and nitrogen co-doped reduced graphene oxide (rGO) is synthesized by a facile method and demonstrated remarkably enhanced activities in metal-free activation of peroxymonosulfate (PMS) for catalytic oxidation of phenol. Based on first-order kinetic model, S-N co-doped rGO (SNG) presents an apparent reaction rate constant of 0.043 ± 0.002 min(-1) , which is 86.6, 22.8, 19.7, and 4.5-fold as high as that over graphene oxide (GO), rGO, S-doped rGO (S-rGO), and N-doped rGO (N-rGO), respectively. A variety of characterization techniques and density functional theory calculations are employed to investigate the synergistic effect of sulfur and nitrogen co-doping. Co-doping of rGO at an optimal sulfur loading can effectively break the inertness of carbon systems, activate the sp(2) -hybridized carbon lattice and facilitate the electron transfer from covalent graphene sheets for PMS activation. Moreover, both electron paramagnetic resonance (EPR) spectroscopy and classical quenching tests are employed to investigate the generation and evolution of reactive radicals on the SNG sample for phenol catalytic oxidation. This study presents a novel metal-free catalyst for green remediation of organic pollutants in water. PMID:25786381

  2. The Greening Dutchman

    DEFF Research Database (Denmark)

    Arnold, Marlen Gabriele; Hockerts, Kai

    2011-01-01

    Sustainability innovation research often focuses on the interrelation and the interaction of influencing factors and actors while neglecting the importance of firm internal initiatives. Based on a longitudinal case study of the Dutch company Royal Philips Electronics, we develop the concept of ‘green flagging’ as a groundbreaking corporate sustainability innovation strategy. This paper describes how Philips uses this approach in its Green Flagship Program (GFP). Philips' GFP is particularly inte...

  3. Green growth and transport

    OpenAIRE

    Perkins, Stephen

    2011-01-01

    Transport figures prominently on green growth agendas. The reason is twofold. First, transport has major environmental impacts in terms of greenhouse gas emissions, local air emissions and noise. And managing congestion more effectively is part of the broader agenda for more sustainable development and better use of resources invested in infrastructure. Second, a large part of public expenditure to stimulate green growth is directed at transport sector industries. This concerns most notably a...

  4. Green space as classroom

    DEFF Research Database (Denmark)

    Bentsen, Peter; Schipperijn, Jasper; Jensen, Frank Søndergaard

    2013-01-01

    More and more Danish teachers have started introducing curriculum-based outdoor learning as a weekly or biweekly ‘outdoor school’ day for school children. This move towards schooling in non-classroom spaces presents a challenge for green space managers. Basic managerial knowledge related to what, who, when and where has thus far only been supported by anecdotal evidence, but seems fundamental to the decision-making of a range of green space providers. The present study aims to describe, characte...

  5. Green buildings pay

    DEFF Research Database (Denmark)

    Naboni, Emanuele; Edwards, Brian

    2012-01-01

    The new edition of ‘Green Buildings Pay’ authored by Brian Edwards and Emanuele Naboni explores the business and professional benefits which derive from architectural design driven by sustainability. With a new sub-title ‘Green Buildings Pay: design, productivity and ecology’ the book argues that environmental design has altered how we design, construct and manage buildings. The book has relevance to those who not only design and engineer buildings but to those who commission architecture and th...

  6. Discretized Thermal Green's Functions

    OpenAIRE

    Granath, Mats; Sabashvili, Andro; Strand, Hugo U. R.; Östlund, Stellan

    2011-01-01

    We present a spectral weight conserving formalism for Fermionic thermal Green's functions that are discretized in imaginary time and thus periodic in imaginary ("Matsubara") frequency. The formalism requires a generalization of the Dyson equation and the Baym-Kadanoff-Luttinger-Ward functional for the free energy. A conformal transformation is used to analytically continue the periodized Matsubara Green's function to the continuous real axis in a way that conserves the disco...

  7. Phytomass production and nutrient accumulation by green manure species

    Directory of Open Access Journals (Sweden)

    José Carlos Soares Mangaravite

    2014-10-01

    Full Text Available Green manuring is recognized as a viable alternative to improve nutrient cycling in soils. The aim of this study was to evaluate the phytomass production and nutrient accumulation in shoots of the summer green manures jack bean [Canavalia ensiformis (L. DC.], dwarf pigeon pea (Cajanus cajanvar var. Flavus DC., dwarf mucuna [Mucuna deeringiana (Bort Merr] and sunn hemp (Crotalaria juncea L., under nitrogen fertilization and/or inoculation with N-fixing bacteria. A split plot design was arranged with the four Fabaceae species as main plots and nitrogen fertilization (with and without and inoculation with diazotrophic bacteria (with and without as the subplots, in a 2² factorial. The experiment was arranged as a randomized complete block design with four replications. In the conditions of this trial, the sunn hemp had the highest production of shoot phytomass (12.4 Mg ha-1 and nutrient accumulation, while the dwarf mucuna had the lowest production of shoot phytomass (3.9 Mg ha-1 and nutrient accumulation. The results showed no effect of nitrogen fertilization or inoculation with N-fixing bacteria on the production of shoot phytomass and nutrient accumulation, except for inoculation without nitrogen fertilization, resulting in greater P accumulation (p <0.05 in the sunn hemp and greater Zn and Mn accumulation in the dwarf mucuna. These findings indicate that N fertilization or inoculation with N2-fixing bacteria for Fabaceae are low efficiency practices in the edaphoclimatic conditions of this study.

  8. IDENTIFICATION OF BACTERIA IN LATEX PAINTS

    Directory of Open Access Journals (Sweden)

    Rojas, J.

    2008-01-01

    Full Text Available The bacteria are prokaryote organisms with a high capacity to colonize many types of habits. This research was developed with the object to identify extremophiles bacteria presents in latex paint. The bacteria were cultivated in culture mediums TSA, Blood Agar, Mc Conkey and finally the biochemical proof API-NF® for bacteria's isolation and identification, respectively. Characterization showed bacterial profile of Pasteurella sp. Hypothesis that could be found extremophiles bacteria in latex paint were demonstrated.

  9. [Genetic resources of nodule bacteria].

    Science.gov (United States)

    Rumiantseva, M L

    2009-09-01

    Nodule bacteria (rhizobia) form highly specific symbiosis with leguminous plants. The efficiency of accumulation of biological nitrogen depends on molecular-genetic interaction between the host plant and rhizobia. Genetic characteristics of microsymbiotic strains are crucial in developing highly productive and stress-resistant symbiotic pairs: rhizobium strain-host plant cultivar (species). The present review considers the issue of studying genetic resources of nodule bacteria to identify genes and their blocks, responsible for the ability of rhizobia to form highly effective symbiosis in various agroecological conditions. The main approaches to investigation of intraspecific and interspecific genetic and genomic diversity of nodule bacteria are considered, from MLEE analysis to the recent methods of genomic DNA analysis using biochips. The data are presented showing that gene centers of host plants are centers of genetic diversification of nodule bacteria, because the intraspecific polymorphism of genetic markers of the core and the accessory rhizobial genomes is extremely high in them. Genotypic features of trapped and nodule subpopulations of alfalfa nodule bacteria are discussed. A survey of literature showed that the genomes of natural strains in alfalfa gene centers exhibit significant differences in genes involved in control of metabolism, replication, recombination, and the formation of defense response (hsd genes). Natural populations of rhizobia are regarded as a huge gene pool serving as a source of evolutionary innovations. PMID:19824536

  10. Relationship between corrosion and the biological sulfur cycle: A review

    Energy Technology Data Exchange (ETDEWEB)

    Little, B.J.; Ray, R.I.; Pope, R.K.

    2000-04-01

    Sulfur and sulfur compounds can produce pitting, crevice corrosion, dealloying, stress corrosion cracking, and stress-oriented hydrogen-induced cracking of susceptible metals and alloys. Even though the metabolic by-products of the biological sulfur cycle are extremely corrosive, there are no correlations between numbers and types of sulfur-related organisms and the probability or rate of corrosion, Determination of specific mechanisms for corrosion caused by microbiologically mediated oxidation and reduction of sulfur and sulfur compounds is complicated by the variety of potential metabolic-energy sources and by-products; the coexistence of reduced and oxidized sulfur species; competing reactions with inorganic and organic compounds; and the versatility and adaptability of microorganisms in biofilms. The microbial ecology of sulfur-rich environments is poorly understood because of the association of aerobes and anaerobes and the mutualism or succession of heterotrophs to autotrophs. The physical scale over which the sulfur cycle influences corrosion varies with the environment. The complete sulfur cycle of oxidation and reduction reactions can take place in macroenvironments, including sewers and polluted harbors, or within the microenvironment of biofilms. In this review, reactions of sulfur and sulfur compounds resulting in corrosion were discussed in the context of environmental processes important to corrosion.

  11. 40 CFR 60.183 - Standard for sulfur dioxide.

    Science.gov (United States)

    2010-07-01

    ...2010-07-01 false Standard for sulfur dioxide. 60.183 Section 60.183...Smelters § 60.183 Standard for sulfur dioxide. (a) On and after the...converter gases which contain sulfur dioxide in excess of 0.065 percent...

  12. 46 CFR 151.50-84 - Sulfur dioxide.

    Science.gov (United States)

    2010-10-01

    ...5 2010-10-01 2010-10-01 false Sulfur dioxide. 151.50-84 Section 151.50-84 Shipping...CARGOES Special Requirements § 151.50-84 Sulfur dioxide. (a) Sulfur dioxide that is transported under the provisions...

  13. 40 CFR 60.173 - Standard for sulfur dioxide.

    Science.gov (United States)

    2010-07-01

    ...2010-07-01 false Standard for sulfur dioxide. 60.173 Section 60.173...Smelters § 60.173 Standard for sulfur dioxide. (a) On and after the...roaster any gases which contain sulfur dioxide in excess of 0.065 percent...

  14. 40 CFR 60.333 - Standard for sulfur dioxide.

    Science.gov (United States)

    2010-07-01

    ...2010-07-01 false Standard for sulfur dioxide. 60.333 Section 60.333...Turbines § 60.333 Standard for sulfur dioxide. On and after the date...turbine any gases which contain sulfur dioxide in excess of 0.015...

  15. 40 CFR 60.82 - Standard for sulfur dioxide.

    Science.gov (United States)

    2010-07-01

    ...2010-07-01 false Standard for sulfur dioxide. 60.82 Section 60.82...Plants § 60.82 Standard for sulfur dioxide. (a) On and after the...facility any gases which contain sulfur dioxide in excess of 2 kg per...

  16. 40 CFR 60.163 - Standard for sulfur dioxide.

    Science.gov (United States)

    2010-07-01

    ...2010-07-01 false Standard for sulfur dioxide. 60.163 Section 60.163...Smelters § 60.163 Standard for sulfur dioxide. (a) On and after the...converter any gases which contain sulfur dioxide in excess of 0.065...

  17. 40 CFR 60.642 - Standards for sulfur dioxide.

    Science.gov (United States)

    2010-07-01

    ...2010-07-01 false Standards for sulfur dioxide. 60.642 Section 60.642...Emissions § 60.642 Standards for sulfur dioxide. (a) During the initial...determined from table 1 based on the sulfur feed rate (X) and the...

  18. Annotated bibliography of methods for determining sulfur and forms of sulfur in coal and coal-related materials

    Energy Technology Data Exchange (ETDEWEB)

    Chriswell, C.D.; Norton, G.A.; Akhtar, S.S.; Straszheim, W.E.; Markuszewski, R.

    1993-01-01

    Over 400 published papers, presentations at scientific meetings, and reports relating to the determination of sulfur and sulfur forms in coal-related materials have been accumulated, classified, and an evaluation made of their content.

  19. Enhanced bioleaching on attachment of indigenous acidophilic bacteria to pyrite surface

    Science.gov (United States)

    Wi, D. W.; Cho, K. H.; Kim, B. J.; Choi, N. C.; Park, C. Y.

    2012-04-01

    In recent years, bioleaching has been widely applied on an industrial scale due to the advantages of low cost and environment friendliness. The direct contact mechanism of bioleaching assumes the action of a metal sulfide-attached cell oxidizing the mineral by an enzyme system with oxygen to sulfate and metal cations. Fundamental surface properties of sulfide particles and leaching-bacteria in bioleaching play the key role in the efficiency of this process. The aim of this work is to investigate of direct contact bioleaching mechanism on pyrite through attachment properties between indigenous acidophilic bacteria and pyrite surfaces. The bacteria were obtained from sulfur hot springs, Hatchobaru thermal electricity plant in Japan. And pyrite was collected from mine waste from Gwang-yang abandoned gold mines, Korea. In XRD analyses of the pyrite, x-ray diffracted d-value belong to pyrite was observed. The indigenous acidophilic bacteria grew well in a solution and over the course of incubation pH decreased and Eh increased. In relation to a bacterial growth-curve, the lag phase was hardly shown while the exponential phase was very fast. Bioleaching experiment result was showed that twenty days after the indigenous acidophilic bacteria were inoculated to a pyrite-leaching medium, the bacterial sample had a greater concentration of Fe and Zn than within the control sample. In SEM-EDS analyses, rod-shaped bacteria and round-shaped microbes were well attached to the surface of pyrite. The size of the rod-shaped bacteria ranged from 1.05~1.10 ? to 4.01~5.38 ?. Round-shaped microbes were more than 3.0 ? in diameter. Paired cells of rod-shaped bacteria were attached to the surface of pyrite linearly.

  20. Vertical Distribution of Heterotrophic Bacteria and Their Culturability In The Northeastern Atlantic (pomme 0 Cruise)

    Science.gov (United States)

    Denis, M.; Moumas, M.; Bianchi, M.

    In the frame of POMME (Programme Océanographie Multidisciplinaire Méso- Echelle) a French oceanographic programme in the Northeastern Atlantic (39-45N and 15-21W), the vertical distribution of heterotrophic bacteria and their culturability were investigated by combining different independent approaches during the POMME 0 cruise in fall 2000. Bacterial abundances and biomasses were determined by flow cytometric analysis of seawater samples, fixed, frozen and stored in liquid nitrogen un- til their analysis in the laboratory. Cells were stained with the green fluorescent probe SYBR Green IIZ´ (Molecular Probes), a specific probe for nucleic acids. The enumer- ated bacteria were pooled into two fractions according to their DNA content. Bacteria with the higher DNA content (HDNA) are considered as the fraction potentially able of undergoing division, whereas cells with the lower DNA content (LDNA) constitute an inactive fraction (Gasol et al., 1999). The viability of the collected bacteria was determined by using the method of Bianchi &Giuliano (1996) based on the formation of micro-colonies. The percentages of dividing bacteria were calculated with respect to the numbers of HDNA bacteria instead of the total counts which contained the irrel- evant LDNA cells. The percentage of dividing bacteria was larger when the bacteria population was dominated by HDNA bacteria. This result suggests that a bacterial population composed mainly of HDNA cells will have a larger capacity to divide than otherwise. The distribution of the bacterial activity at the sampled stations showed that conditions for the heterotrophic bacteria development were more favorable in the south western zone of the study area. The observed bacterial abundances were in the range 3.7 104 - 5.3 105 cells cm-3. The percentages of the LDNA fractions were in the range 40 - 90%, suggesting the occurrence of a declining ecosystem. The installa- tion of an oligotrophic system was supported by the observation of high abundances of Prochlorococcus, the dominant species in oligotrophic waters of the Atlantic or the Pacific Oceans. Bianchi A., Giuliano L. (1996) Enumeration of viable bacteria in the marine pelagic environment. Appl. Environ. Microb. 62 : 174-177. Gasol J.M., Zweifel U.I., Peters F., Furhman J.A., Hagström A. (1999) Significance of size and nucleic acid content heterogeneity as measured by flow cytometry in natural planktonic bacteria. Appl. 1 Environ. Microb. 65 : 4475-4483. 2

  1. Green tea yogurt: major phenolic compounds and microbial growth.

    Science.gov (United States)

    Amirdivani, Shabboo; Baba, Ahmad Salihin Hj

    2015-07-01

    The purpose of this study was to evaluate fermentation of milk in the presence of green tea (Camellia sinensis) with respect to changes in antioxidant activity, phenolic compounds and the growth of lactic acid bacteria. Pasteurized full fat cow's milk and starter culture were incubated at 41 °C in the presence of two different types of green tea extracts. The yogurts formed were refrigerated (4 °C) for further analysis. The total phenolic content was highest (p?yogurt (MGT) followed by steam-treated green tea (JGT) and plain yogurts. Four major compounds in MGTY and JGTY were detected. The highest concentration of major phenolic compounds in both samples was related to quercetin-rhamnosylgalactoside and quercetin-3-O-galactosyl-rhamnosyl-glucoside for MGTY and JGTY respectively during first 7 day of storage. Diphenyl picrylhydrazyl and ferric reducing antioxidant power methods showed highest antioxidant capacity in MGTY, JGTY and PY. Streptococcus thermophillus and Lactobacillus spp. were highest in MGTY followed by JGTY and PY. This paper evaluates the implementation of green tea yogurt as a new product with functional properties and valuable component to promote the growth of beneficial yogurt bacteria and prevention of oxidative stress by enhancing the antioxidant activity of yogurt. PMID:26139940

  2. Sulfur and selen clusters in nanoporous carbon

    International Nuclear Information System (INIS)

    The results of X-ray diffraction, X-ray photoelectron spectroscopy, electrical, and galvanomagnetic studies of nanoporous carbon with sulfur and selenium nanoclusters introduced into pores are analyzed. Conclusions are drawn concerning the short-range order in the introduced clusters and their interaction with carbon

  3. SULFUR DIOXIDE OXIDATION REACTIONS IN AQUEOUS SOLUTIONS

    Science.gov (United States)

    This is the final report on a three year project to study the kinetics and mechanisms of some 105 reactions involving the aqueous oxidation of sulfur dioxide and nitrogen oxides in mixed catalyst-oxidant systems at low pH (0-3). The 105 systems involve six redox reaction types: S...

  4. Obtainment of sodium vanadate in sulfuric medium

    International Nuclear Information System (INIS)

    This paper presents the result of a some of the operational variables, in the precipitation of sodium vanadates in sulfuric medium at temperature of 600C, such as: initial Ph of precipitation, solution aging, intensity of agitation, H2SO4 concentration of titration solutions, cooling rate solution after neutralization and addition rate of neutralization solution. (author)

  5. Hot-Gas Desulfurization with Sulfur Recovery

    International Nuclear Information System (INIS)

    The objective of this study is to develop a second generation HGD process that regenerates the sulfided sorbent directly to elemental sulfur using SO2, with minimal consumption of coal gas. The goal is to have better overall economics than DSRP when integrated with the overall IGCC system

  6. Helium and Sulfur Hexafluoride in Musical Instruments

    Science.gov (United States)

    Forinash, Kyle; Dixon, Cory L.

    2014-01-01

    The effects of inhaled helium on the human voice were investigated in a recent article in "The Physics Teacher." As mentioned in that article, demonstrations of the effect are a popular classroom activity. If the number of YouTube videos is any indication, the effects of sulfur hexafluoride on the human voice are equally popular.…

  7. RETENTION OF SULFUR DIOXIDE BY NYLON FILTERS

    Science.gov (United States)

    Based on laboratory studies, recovery efficiencies of sulfur dioxide (SO2) were determined for nylon filters. The nylon filters used in these experiments were found to retain SO2. A relatively uniform amount (1.7%) was recoverable from each nylon filter, independent of relative...

  8. Sulfur and selenium isotope separation by distillation

    International Nuclear Information System (INIS)

    Sulfur and selenium isotopes are used for labeled compounds and as precursors for radioisotope production; however, both limited availability and high costs are problems. A new method is needed for large-scale separation of theses isotopes. Experimental distillation columns were used to measure isotopic separations for sulfur and selenium compounds. The maximum total isotope separations of 32S vs. 34S were 1.127 for H2S, 1.048 for COS, 0.838 for SF4, and 1.058 for CH3SH. Relative volatilities of 32S and 34S are 1.0006 for COS and 0.9976 for SF4. There is a reverse isotope effect for carbon in COS. No isotopic separation was observed for dimethyl selenide. The lower mass selenium isotopes in H2Se are more volatile. Distillation is a promising method for separating sulfur isotopes on a production scale. Existing distillation technology produces separated isotopes with an effect similar to that found for sulfur in SF4. (author). 8 refs.; 2 tabs

  9. Sulfur and selenium isotope separation by distillation

    International Nuclear Information System (INIS)

    Sulfur and selenium isotopes are used for labeled compounds and as precursors for radioisotope production; however, both limited availability and high costs are problems. A new method is needed for large-scale separation of these isotopes. Experimental distillation columns were used to measure isotopic separations for sulfur and selenium compounds. The maximum total isotope separation of 32S vs. 34S were 1.127 for H2S, 1.048 for COS, 0.838 for SF4, and 1.058 for CH3SH. Relative volatilities of 32S vs. 34S are 1.0006 for COS and 0.9976 for SF4. There is a reverse isotope effect for carbon in COS. No isotopic separation was observed for dimethyl selenide. The lower mass selenium isotopes in H2Se are more volatile. Distillation is a promising method for separating sulfur isotopes on a production scale. Existing distillation technology produced separated isotopes with an effect similar to that found for sulfur in SF4. 8 refs., 2 tabs

  10. Development of enhanced sulfur rejection processes

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, R.H.; Luttrell, G.H.; Adel, G.T.; Richardson, P.E.

    1996-03-01

    Research at Virginia Tech led to the development of two complementary concepts for improving the removal of inorganic sulfur from many eastern U.S. coals. These concepts are referred to as Electrochemically Enhanced Sulfur Rejection (EESR) and Polymer Enhanced Sulfur Rejection (PESR) processes. The EESR process uses electrochemical techniques to suppress the formation of hydrophobic oxidation products believed to be responsible for the floatability of coal pyrite. The PESR process uses polymeric reagents that react with pyrite and convert floatable middlings, i.e., composite particles composed of pyrite with coal inclusions, into hydrophilic particles. These new pyritic-sulfur rejection processes do not require significant modifications to existing coal preparation facilities, thereby enhancing their adoptability by the coal industry. It is believed that these processes can be used simultaneously to maximize the rejection of both well-liberated pyrite and composite coal-pyrite particles. The project was initiated on October 1, 1992 and all technical work has been completed. This report is based on the research carried out under Tasks 2-7 described in the project proposal. These tasks include Characterization, Electrochemical Studies, In Situ Monitoring of Reagent Adsorption on Pyrite, Bench Scale Testing of the EESR Process, Bench Scale Testing of the PESR Process, and Modeling and Simulation.

  11. Graphene-Wrapped Sulfur Particles as a Rechargeable Lithium-Sulfur-Battery Cathode Material with High Capacity and Cycling Stability

    OpenAIRE

    WANG, HAILIANG; Yang, Yuan; Liang, Yongye; Robinson, Joshua Tucker; Li, Yanguang; Jackson, Ariel; Cui, Yi; Dai, Hongjie

    2011-01-01

    We report the synthesis of a graphene-sulfur composite material by wrapping polyethyleneglycol (PEG) coated submicron sulfur particles with mildly oxidized graphene oxide sheets decorated by carbon black nanoparticles. The PEG and graphene coating layers are important to accommodating volume expansion of the coated sulfur particles during discharge, trapping soluble polysulfide intermediates and rendering the sulfur particles electrically conducting. The resulting graphene-s...

  12. Sulfur and oxygen isotope insights into sulfur cycling in shallow-sea hydrothermal vents, Milos, Greece

    OpenAIRE

    Gilhooly, William P; Fike, David A; Druschel, Gregory K; Kafantaris, Fotios-Christos A; Price, Roy E.; Amend, Jan P.

    2014-01-01

    Shallow-sea (5 m depth) hydrothermal venting off Milos Island provides an ideal opportunity to target transitions between igneous abiogenic sulfide inputs and biogenic sulfide production during microbial sulfate reduction. Seafloor vent features include large (>1 m2) white patches containing hydrothermal minerals (elemental sulfur and orange/yellow patches of arsenic-sulfides) and cells of sulfur oxidizing and reducing microorganisms. Sulfide-sensitive film deployed in the vent and non-vent s...

  13. The Influence of Environmental Friendliness on Green Trust: The Mediation Effects of Green Satisfaction and Green Perceived Quality

    Directory of Open Access Journals (Sweden)

    Yu-Shan Chen

    2015-07-01

    Full Text Available As global green trends became more prevalent, green marketing also developed into an important issue. Although prior literature explored the main factors affecting green trust, it was inconclusive as to how environmental friendliness could affect the green trust in green marketing. This study aims to focus on the positive influence of environmental friendliness on green trust, and explore the mediation effects of green satisfaction and green perceived quality. This study undertakes an empirical study by means of questionnaire survey. The respondents are consumers who have experience purchasing green products. This study applies structural equation modeling (SEM to test the hypotheses. The findings of this study indicate that (1 environmental friendliness has a significant positive impact on green satisfaction, green perceived quality, and green trust; (2 both green satisfaction and green perceived quality positively affect green trust; and (3 green satisfaction and green perceived quality partially mediate the positive relationship between environmental friendliness and green trust.

  14. Effects of sulfur oxides on eicosanoids

    International Nuclear Information System (INIS)

    Ultrafine metal oxides and SO2 react during coal combustion or smelting operations to form primary emissions coated with an acidic SOx layer. Ongoing work in this laboratory has examined the effects of sulfur oxides on pulmonary functions of guinea pigs. We have previously reported that 20 micrograms/m3 acidic sulfur oxide as a surface layer on ultrafine ZnO particles decreases lung volumes, decreases carbon monoxide diffusing capacity, and causes lung inflammation in guinea pigs after 4 daily 3-h exposures. It also produces bronchial hypersensitivity following a single 1-h exposure. The importance of this surface layer is demonstrated by our observation that 200 micrograms/m3 of sulfuric acid droplets of equivalent size are needed to produce the same degree of hypersensitivity. This study characterized the concentration-dependent effects of in vivo exposures to sulfur oxides on arachidonic acid metabolism in the guinea pig lung, and investigated the time course and the relation between eicosanoid composition and pulmonary functions. We focused specifically on four cyclooxygenase metabolites of arachidonic acid, that is, prostaglandins (PG) E1, F2 alpha, 6-keto prostaglandin F1 alpha, and thromboxane (Tx) B2, and two groups of sulfidopeptide leukotrienes (C4, D4, E4, and F4). Guinea pigs were exposed to ultrafine ZnO aerosol (count median diameter = 0.05 microns, sigma g = 1.80) with a layer of acidic sulfur oxide on the surface of the particles. Lung lavage was collected after exposures, and the levels of arachidonic acid metabolites were determined using radioimmunoassay (RIA). Concentration-dependent promotion of PGF2 alpha and concentration-dependent suppression of LtB4 were observed. The increased PGF2 alpha was associated with depressed vital capacity and diffusing capacity of the lungs measured in guinea pigs exposed to the same atmosphere described in a previous study

  15. Hydrolysis of Sulfur Dioxide in Small Clusters of Sulfuric Acid: Mechanistic and Kinetic Study.

    Science.gov (United States)

    Liu, Jingjing; Fang, Sheng; Wang, Zhixiu; Yi, Wencai; Tao, Fu-Ming; Liu, Jing-Yao

    2015-11-17

    The deposition and hydrolysis reaction of SO2 + H2O in small clusters of sulfuric acid and water are studied by theoretical calculations of the molecular clusters SO2-(H2SO4)n-(H2O)m (m = 1,2; n = 1,2). Sulfuric acid exhibits a dramatic catalytic effect on the hydrolysis reaction of SO2 as it lowers the energy barrier by over 20 kcal/mol. The reaction with monohydrated sulfuric acid (SO2 + H2O + H2SO4 - H2O) has the lowest energy barrier of 3.83 kcal/mol, in which the cluster H2SO4-(H2O)2 forms initially at the entrance channel. The energy barriers for the three hydrolysis reactions are in the order SO2 + (H2SO4)-H2O > SO2 + (H2SO4)2-H2O > SO2 + H2SO4-H2O. Furthermore, sulfurous acid is more strongly bonded to the hydrated sulfuric acid (or dimer) clusters than the corresponding reactant (monohydrated SO2). Consequently, sulfuric acid promotes the hydrolysis of SO2 both kinetically and thermodynamically. Kinetics simulations have been performed to study the importance of these reactions in the reduction of atmospheric SO2. The results will give a new insight on how the pre-existing aerosols catalyze the hydrolysis of SO2, leading to the formation and growth of new particles. PMID:26450714

  16. Consistency Between Measurements and Theory for Sulfur Gases and Oxidants During the Pacific Atmospheric Sulfur Experiment

    Science.gov (United States)

    Heikes, B. G.; Higbie, A.; O'Sullivan, D. W.; Bandy, A. R.; Mauldin, L.; Cantrell, C.; Anderson, R. S.; Campos, T.; Huebert, B.; Bloomquist, B.; Wang, Y.; Heizer, C. G.; Pollack, I. B.; Weinheimer, A. J.

    2008-12-01

    Airborne gas phase measurements of sulfur dioxide, dimethylsulfide, dimethylsulfoxide, methane sulfonic acid, sulfuric acid, hydroxyl, perhydroxyl, hydrogen peroxide, methylhydroperoxide, ozone, and carbon monoxide together with aerosol microphysical properties and bulk and size-dependent aerosol composition are examined for consistency with photochemical theory. The observations come from 14 research flights using the NCAR C-130 flown mostly southeast of Kiritimati in relatively cloud-free marine boundary layer air. This region was chosen because of its extremely low nitrogen oxide mixing ratios and minimal horizontal gradients in composition. A size-dependent gas-particle mass-transfer model is used to calculate the exchange rates of dimethylsulfoxide, methanesulfonic acid and sulfuric acid between the gas and aerosol. Gas kinetic reactions, aqueous reactions, and heterogeneous processes are used in the evaluation. Mass accommodation coefficients, Henry's Law solubilities, and the effective yields of methanesulfonic acid, sulfur dioxide, sulfuric acid and dimethylsulfoxide from dimethylsulfide are estimated and consistent with the literature. Gas phase hydroxyl chemistry alone is sufficient to explain observed methanesulfonic acid and sulfuric acid vapor concentrations.

  17. Preparation and electrochemical performance of sulfur-alumina cathode material for lithium-sulfur batteries

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Kang [Faculty of Material Science and Chemistry, China University of Geosciences, 388 Lumo Road, 430074 Wuhan (China); Wang, Shengping, E-mail: spwang@cug.edu.cn [Faculty of Material Science and Chemistry, China University of Geosciences, 388 Lumo Road, 430074 Wuhan (China); Zhang, Hanyu; Wu, Jinping [Faculty of Material Science and Chemistry, China University of Geosciences, 388 Lumo Road, 430074 Wuhan (China)

    2013-06-01

    Highlights: ? Micron-sized alumina was synthesized as adsorbent for lithium-sulfur batteries. ? Sulfur-alumina material was synthesized via crystallizing nucleation. ? The Al{sub 2}O{sub 3} can provide surface area for the deposition of Li{sub 2}S and Li{sub 2}S{sub 2}. ? The discharge capacity of the battery is improved during the first several cycles. - Abstract: Nano-sized sulfur particles exhibiting good adhesion with conducting acetylene black and alumina composite materials were synthesized by means of an evaporated solvent and a concentrated crystallization method for use as the cathodes of lithium-sulfur batteries. The composites were characterized and examined by X-ray diffraction, environmental scanning electron microscopy and electrochemical methods, such as cyclic voltammetry, electrical impedance spectroscopy and charge–discharge tests. Micron-sized flaky alumina was employed as an adsorbent for the cathode material. The initial discharge capacity of the cathode with the added alumina was 1171 mAh g{sup ?1}, and the remaining capacity was 585 mAh g{sup ?1} after 50 cycles at 0.25 mA cm{sup ?2}. Compared with bare sulfur electrodes, the electrodes containing alumina showed an obviously superior cycle performance, confirming that alumina can contribute to reducing the dissolution of polysulfides into electrolytes during the sulfur charge–discharge process.

  18. Preparation and electrochemical performance of sulfur-alumina cathode material for lithium-sulfur batteries

    International Nuclear Information System (INIS)

    Highlights: ? Micron-sized alumina was synthesized as adsorbent for lithium-sulfur batteries. ? Sulfur-alumina material was synthesized via crystallizing nucleation. ? The Al2O3 can provide surface area for the deposition of Li2S and Li2S2. ? The discharge capacity of the battery is improved during the first several cycles. - Abstract: Nano-sized sulfur particles exhibiting good adhesion with conducting acetylene black and alumina composite materials were synthesized by means of an evaporated solvent and a concentrated crystallization method for use as the cathodes of lithium-sulfur batteries. The composites were characterized and examined by X-ray diffraction, environmental scanning electron microscopy and electrochemical methods, such as cyclic voltammetry, electrical impedance spectroscopy and charge–discharge tests. Micron-sized flaky alumina was employed as an adsorbent for the cathode material. The initial discharge capacity of the cathode with the added alumina was 1171 mAh g?1, and the remaining capacity was 585 mAh g?1 after 50 cycles at 0.25 mA cm?2. Compared with bare sulfur electrodes, the electrodes containing alumina showed an obviously superior cycle performance, confirming that alumina can contribute to reducing the dissolution of polysulfides into electrolytes during the sulfur charge–discharge process

  19. Pathways of sulfide oxidation by haloalkaliphilic bacteria in limited-oxygen gas lift bioreactors.

    Science.gov (United States)

    Klok, Johannes B M; van den Bosch, Pim L F; Buisman, Cees J N; Stams, Alfons J M; Keesman, Karel J; Janssen, Albert J H

    2012-07-17

    Physicochemical processes, such as the Lo-cat and Amine-Claus process, are commonly used to remove hydrogen sulfide from hydrocarbon gas streams such as landfill gas, natural gas, and synthesis gas. Biodesulfurization offers environmental advantages, but still requires optimization and more insight in the reaction pathways and kinetics. We carried out experiments with gas lift bioreactors inoculated with haloalkaliphilic sulfide-oxidizing bacteria. At oxygen-limiting levels, that is, below an O(2)/H(2)S mole ratio of 1, sulfide was oxidized to elemental sulfur and sulfate. We propose that the bacteria reduce NAD(+) without direct transfer of electrons to oxygen and that this is most likely the main route for oxidizing sulfide to elemental sulfur which is subsequently oxidized to sulfate in oxygen-limited bioreactors. We call this pathway the limited oxygen route (LOR). Biomass growth under these conditions is significantly lower than at higher oxygen levels. These findings emphasize the importance of accurate process control. This work also identifies a need for studies exploring similar pathways in other sulfide oxidizers such as Thiobacillus bacteria. PMID:22697609

  20. Sulfur dimers adsorbed on Au(111) as building blocks for sulfur octomers formation: A density functional study

    International Nuclear Information System (INIS)

    Experimental scanning tunneling microscopy (STM) studies have shown for more than two decades rectangular formations when sulfur atoms are deposited on Au(111) surfaces. The precursors have ranged from simple molecules or ions, such as SO2 gas or sulfide anions, to more complex organosulfur compounds. We investigated, within the framework of the Density Functional Theory, the structure of these rectangular patterns assuming them entirely composed of sulfur atoms as the experimental evidence suggests. The sulfur coverage at which the simulations were carried out (0.67 ML or higher) provoked that the sulfur-sulfur association had to be taken into account for achieving a good agreement between the sets of simulated and experimental STM images. A combination of four sulfur dimers per rectangular formation properly explained the trends obtained by the experimental STM analysis which were related with the rectangles' size and shape fluctuations together with sulfur-sulfur distances within these rectangles. Finally, a projected density of states analysis showed that the dimers were capable of altering the Au(5d) electronic states at the same level as atomic sulfur adsorbed at low coverage. Besides, sulfur dimers states were perfectly distinguished, whose presence near and above the Fermi level can explain both: sulfur-sulfur bond elongation and dimers stability when they stayed adsorbed on the surface at high coverage

  1. Frontispiece: Hollow Carbon Nanofibers Filled with MnO2 Nanosheets as Efficient Sulfur Hosts for Lithium-Sulfur Batteries.

    Science.gov (United States)

    Li, Zhen; Zhang, Jintao; Lou, Xiong Wen David

    2015-10-26

    Lithium-Sulfur Batteries Hollow carbon nanofibers filled with MnO2 nanosheets were synthesized by X.?W. Lou and co-workers in their Communication on page?12886?ff., and shown to be a suitable sulfur host for lithium-sulfur batteries. PMID:26480342

  2. ADAPTATIONS OF INDIGENOUS BACTERIA TO FUEL CONTAMINATION IN KARST AQUIFERS IN SOUTH-CENTRAL KENTUCKY

    Science.gov (United States)

    Byl, Thomas D.; Metge, David W.; Daniel T. Agymang; Bradley, Michael W.; Hileman, Gregg; Harvey, Ronald W.

    2014-01-01

    The karst aquifer systems in southern Kentucky can be dynamic and quick to change. Microorganisms that live in these unpredictable aquifers are constantly faced with environmental changes. Their survival depends upon adaptations to changes in water chemistry, taking advantage of positive stimuli and avoiding negative environmental conditions. The U.S. Geological Survey conducted a study in 2001 to determine the capability of bacteria to adapt in two distinct regions of water quality in a karst aquifer, an area of clean, oxygenated groundwater and an area where the groundwater was oxygen depleted and contaminated by jet fuel. Water samples containing bacteria were collected from one clean well and two jet fuel contaminated wells in a conduit-dominated karst aquifer. Bacterial concentrations, enumerated through direct count, ranged from 500,000 to 2.7 million bacteria per mL in the clean portion of the aquifer, and 200,000 to 3.2 million bacteria per mL in the contaminated portion of the aquifer over a twelve month period. Bacteria from the clean well ranged in size from 0.2 to 2.5 mm, whereas bacteria from one fuel-contaminated well were generally larger, ranging in size from 0.2 to 3.9 mm. Also, bacteria collected from the clean well had a higher density and, consequently, were more inclined to sink than bacteria collected from contaminated wells. Bacteria collected from the clean portion of the karst aquifer were predominantly (,95%) Gram-negative and more likely to have flagella present than bacteria collected from the contaminated wells, which included a substantial fraction (,30%) of Gram-positive varieties. The ability of the bacteria from the clean portion of the karst aquifer to biodegrade benzene and toluene was studied under aerobic and anaerobic conditions in laboratory microcosms. The rate of fuel biodegradation in laboratory studies was approximately 50 times faster under aerobic conditions as compared to anaerobic, sulfur-reducing conditions. The optimum pH for fuel biodegradation ranged from 6 to 7. These findings suggest that bacteria have adapted to water-saturated karst systems with a variety of active and passive transport mechanisms.

  3. Characteristics of sulfur isotope during the epigenetic alteration of oil-gas and coalbed methane in the southeastern Songliao Basin

    International Nuclear Information System (INIS)

    Through studying the characteristics of pyrite and sulfur isotope in the rock of Upper Cretaceous Quantou Formation, Yaojia Formation and Nenjiang Formation in the southeastern Songliao Basin, occurrence features of pyrite and characteristics of sulfur isotope in gray and grayish-green sandstone produced by epigenetic reducing decoloration of Quantou Formation and Yaojia Formation indicate the characteristics of organic fluid composition in deep-seated oil-gas and coalbed methane. ?34SV-CDT of sulfur isotope in original sedimentary diagenite is positive, ?34SV-CDT of organic fluid in oil-gas and coalbed methane is negative. Reduction of oil-gas and coalbed methane not only makes mottled and purplish-red original oxidized sandstone reduce to grey and grayish-green reducing sandstone, which makes the reducing capacities of rocks increase greatly, but also uranium is superimposed and enriched during the interaction of rocks with organic fluid of oil-gas and coalbed methane and uranium content increases generally, which results in the forming of uranium anomaly and mineralization in some areas. Stockwork damouritization is discovered in the ore-bearing sandstone of Yaojia Formation in Menda area at the first time, which shows the uranium mineralization is characterized by low temperature hydrothermal alteration and is related with low temperature hydrothermal fluid. (authors)

  4. Estimation of the production rate of bacteria in the rumen of buffalo calves

    International Nuclear Information System (INIS)

    The rate of bacterial cell growth in the rumen of buffalo calves has been measured applying the isotope dilution technique by injecting labelled mixed rumen bacteria into the rumen, and expressing the specific radioactivity either per mg dry bacterial cells or per ?g DAPA in whole rumen samples. The animals were fed daily about 15-20 kg chopped green maize in 12 equal amounts at 2-h intervals. There was no significant difference in the rate of production of bacteria estimated by either method. (author)

  5. Method to prevent sulfur accumulation in membrane electrode assembly

    Science.gov (United States)

    Steimke, John L; Steeper, Timothy J; Herman, David T

    2014-04-29

    A method of operating a hybrid sulfur electrolyzer to generate hydrogen is provided that includes the steps of providing an anolyte with a concentration of sulfur dioxide, and applying a current. During steady state generation of hydrogen a plot of applied current density versus concentration of sulfur dioxide is below a boundary line. The boundary line may be linear and extend through the origin of the graph with a slope of 0.001 in which the current density is measured in mA/cm2 and the concentration of sulfur dioxide is measured in moles of sulfur dioxide per liter of anolyte.

  6. Experiments on contrail formation from fuels with different sulfur content

    Energy Technology Data Exchange (ETDEWEB)

    Busen, R.; Kuhn, M.; Petzold, A.; Schroeder, F.; Schumann, U. [Deutsche Forschungs- und Versuchsanstalt fuer Luft- und Raumfahrt e.V., Oberpfaffenhofen (Germany); Baumgardner, D. [National Center for Atmospheric Research, Boulder, CO (United States); Borrmann, S. [Mainz Univ. (Germany); Hagen, D.; Whitefield, Ph. [Missouri Univ., Rolla, MO (United States). Bureau of Mines; Stroem, J. [Stockholm Univ. (Sweden)

    1997-12-31

    A series of both flight tests and ground experiments has been performed to evaluate the role of the sulfur contained in kerosene in condensation trail (contrail) formation processes. The results of the first experiments are compiled briefly. The last SULFUR 4 experiment dealing with the influence of the fuel sulfur content and different appertaining conditions is described in detail. Different sulfur mass fractions lead to different particle size spectra. The number of ice particles in the contrail increases by about a factor of 2 for 3000 ppm instead of 6 ppm sulfur fuel content. (author) 10 refs.

  7. Reactivity of elemental sulfur nanoparticles and their role on the formation of sulfur intermediates

    Science.gov (United States)

    Kafantaris, F. C. A.; Druschel, G.

    2014-12-01

    Sulfur biogeochemical cycling involves a vast network of chemical reactions including oxidation, reduction and disproportionation, polymerization (S-S bonding), and aggregation that leads to nanoparticulate elemental sulfur (S8(nano)) and eventually the most stable bulk mineral form, a-S8. These reactions can occur in aqueous systems inorganically, intracellularly as assimilatory or dissimilatory reactions in microbial cells, or in presence of microbial organic exudates (e.g. surfactants). Elemental sulfur participates in nucleophilic and hydrolysis reactions to form sulfur intermediates, such as polysulfide ions. The nucleophilic reaction with sulfide (as H2S or HS-, reaction 1), is a key process in the dissolution of elemental sulfur: xS8 + H2S = Sx2- + 2 H+ (1) Polysulfides are inherently unstable in acidic conditions, experiencing a series of chain elongation reactions to form the S8 ring form of molecular elemental sulfur (overall this is the reverse of reaction 1). S8 rings are also inherently insoluble in water and undergo a very rapid coarsening process to form S8nano that then coarsens more slowly via an Ostwald ripening process to form colloidal particles of a-S8. Coarsening kinetics are influenced by temperature, and the presence/absence and type of surfactants [1]. The amount of polysulfide at any point is thus a balance between the forward and reverse overall reactions represented in reaction 1, and influenced by microbial generation of reduced sulfide and/or microbial production of organic surfactants, and the size of the elemental sulfur particles. Here we present some preliminary data on the kinetics of elemental sulfur consumption (reaction 1) that have been tested in various sizes and surface properties of the sulfur nanoparticles. The surface area and presence (or absence) of surfactant molecules influences the kinetics of polysulfide formation. The cycling of that reaction may play a significant role to the element's bioavailability to microorganisms, which incorporate the nanoparticulate (rather than the bulk a-S8) form of elemental sulfur or polysulfides in their specific metabolisms [2]. 1. Garcia and Druschel (2014) Submitted Manuscript 2. Boyd and Druschel (2013) Appl. Environ. Microbiol. 79 (6) 2061-2068

  8. Transient Studies of a Sodium Sulfur Cell

    Science.gov (United States)

    Caprio, Sarah

    Modern grids will include input from fossil-fueled power generation facilities as well as renewable energy sources, and these are expected to work together actively. One major problem with this integrated power production is that most renewable energy sources are intermittent and variable, and thus introduce a very challenging situation with regard to grid stability and reliability. Also, fossil-fueled power generation facilities have load cycles based on expected usage. A non-reliable power source cannot feasibly be used to supply the grid with proper amounts of energy needed in peak times. A solution to this dilemma is power storage. The sodium-sulfur battery has high potential for electrical storage at the grid level due to its high energy density, low cost of the reactants, and high open-circuit voltage. However, the use of sodium-sulfur batteries at the grid level requires high current density operation that can cause cell deterioration, leading to lower sulfur utilization and lower energy efficiency. In addition, it can result in undesired thermal runaway leading to potentially hazardous situations. A rigorous, dynamic model of a sodium-sulfur battery can be used to study these phenomena, design the battery for optimal transient performance, and develop mitigation strategies. Most literature on sodium-sulfur batteries is concerned the dynamics of the sulfur electrode (a sodium-polysulfide melt). There is limited data in the open literature for dynamics of an entire cell. With this motivation, a first-principles dynamic model of a sodium-sulfur cell (with beta"-alumina electrolyte) has been developed. The state of discharge (SOD) of a sodium-sulfur cell significantly affects the heat generation rate, rates of electrochemical reactions, and internal resistance. To capture these phenomena correctly, a fully coupled thermal-electrochemical model has been developed. The thermal model considers heat generation due to Ohmic loss, Peltier heat, and heat due to the entropy change. Species conservation equations are written in the sulfur electrode by considering the phase transition and change in the composition depending on the SOD. The electrochemical reactions are modeled by using Arrhenius-type rate equations with temperature-dependent terms and varying species concentration depending on the SOD. Species conservation equations are written in the beta"-alumina electrolyte for the ionic species by considering the change in composition due to diffusion and migration. In addition, the potential distribution, and the cell resistance for this spatially distributed system has been modeled. The physicochemical properties are considered to be temperature-dependent. The model is used to study both charging and discharging characteristics of the cell at varying current densities. The PDE-based model is solved in Aspen Custom Modeler by using method of lines. Our work shows that an appropriate thermal management strategy is necessary for high current-density operation, especially in the case of high penetration of the renewable energy into the grid.

  9. Sustainable Hydrogen Photoproduction by Phosphorus-Deprived Marine Green Microalgae Chlorella sp.

    Directory of Open Access Journals (Sweden)

    Khorcheska Batyrova

    2015-01-01

    Full Text Available Previously it has been shown that green microalga Chlamydomonas reinhardtii is capable of prolonged H2 photoproduction when deprived of sulfur. In addition to sulfur deprivation (-S, sustained H2 photoproduction in C. reinhardtii cultures can be achieved under phosphorus-deprived (-P conditions. Similar to sulfur deprivation, phosphorus deprivation limits O2 evolving activity in algal cells and causes other metabolic changes that are favorable for H2 photoproduction. Although significant advances in H2 photoproduction have recently been realized in fresh water microalgae, relatively few studies have focused on H2 production in marine green microalgae. In the present study phosphorus deprivation was applied for hydrogen production in marine green microalgae Chlorella sp., where sulfur deprivation is impossible due to a high concentration of sulfates in the sea water. Since resources of fresh water on earth are limited, the possibility of hydrogen production in seawater is more attractive. In order to achieve H2 photoproduction in P-deprived marine green microalgae Chlorella sp., the dilution approach was applied. Cultures diluted to about 0.5–1.8 mg Chl·L?1 in the beginning of P-deprivation were able to establish anaerobiosis, after the initial growth period, where cells utilize intracellular phosphorus, with subsequent transition to H2 photoproduction stage. It appears that marine microalgae during P-deprivation passed the same stages of adaptation as fresh water microalgae. The presence of inorganic carbon was essential for starch accumulation and subsequent hydrogen production by microalgae. The H2 accumulation was up to 40 mL H2 gas per 1iter of the culture, which is comparable to that obtained in P-deprived C. reinhardtii culture.

  10. Plant sulfur nutrition: From Sachs to Big Data.

    Science.gov (United States)

    Kopriva, Stanislav

    2015-09-01

    Together with water and carbon dioxide plants require 14 essential mineral nutrients to finish their life cycle. The research in plant nutrition can be traced back to Julius Sachs, who was the first to experimentally prove the essentiality of mineral nutrients for plants. Among those elements Sachs showed to be essential is sulfur. Plant sulfur nutrition has been not as extensively studied as the nutrition of nitrogen and phosphate, probably because sulfur was not limiting for agriculture. However, with the reduction of atmospheric sulfur dioxide emissions sulfur deficiency has become common. The research in sulfur nutrition has changed over the years from using yeast and algae as experimental material to adopting Arabidopsis as the plant model as well as from simple biochemical measurements of individual parameters to system biology. Here the evolution of sulfur research from the times of Sachs to the current Big Data is outlined. PMID:26305261

  11. Construction of arsB and tetH Mutants of the Sulfur-Oxidizing Bacterium Acidithiobacillus caldus by Marker Exchange?

    OpenAIRE

    van Zyl, Leonardo J.; van Munster, Jolanda M.; Rawlings, Douglas E

    2008-01-01

    Acidithiobacillus caldus is a moderately thermophilic, acidophilic bacterium that has been reported to be the dominant sulfur oxidizer in stirred-tank processes used to treat gold-bearing arsenopyrite ores. It is also widely distributed in heap reactors used for the extraction of metals from ores. Not only are these bacteria commercially important, they have an interesting physiology, the study of which has been restricted by the nonavailability of defined mutants. A recently reported conjuga...

  12. Deodorant bacteria; Des bacteries desodorisantes

    Energy Technology Data Exchange (ETDEWEB)

    Fanlo, J.L. [Ecole Nationale Superieure des Mines, 30 - Ales (France)

    1998-02-01

    Purifying bacteria: if this concept is not new, its application to gases cleansing has only been developed recently. This method allows to eliminate the volatile organic compounds and the gaseous effluents odors which come from industrial sites. Three bioreactors types exist at the present time. Their principles are explained. (O.M.) 6 refs.

  13. Biogeochemical Cycling of Sulfur in Soil

    Science.gov (United States)

    Lehmann, J.; Solomon, D.; Janzen, H.; Amelung, W.; Lobe, I.; Martinez, C. E.; Dupreez, C.; Machado, S.

    2002-12-01

    Sulfur is an important element of the global biogeochemical cycle, since it is highly reactive and moves freely among the lithosphere, atmosphere and hydrosphere. Climatic and environmental changes affecting sulfur in the pedosphere will inevitably change the rate and forms of global sulfur cycling which are intertwined with that of carbon, nitrogen and phosphorus. In soil, inorganic sulfur derived from atmospheric deposition or fertilization is largely immobilized and incorporated into soil organic matter (>95%). During the last decades, however, these emissions have been significantly reduced in North America and Europe, and S deficiency can increasingly be observed in crops. This process was accelerated by a change to low-S-containing fertilizers. Therefore, we studied the long-term dynamics of S forms in relation to organic C to evaluate its impact on the soil cycle. Synchrotron-based sulfur K-edge X-ray Absorption Near-Edge Structure spectroscopy (XANES) was used to speciate and quantify the different oxidation states of soil sulfur (organic and inorganic forms of S). Direct measurement of S species in bulk soil indicated the presence of large background on the spectra, which could not easily be corrected without affecting the results. However, humic acid extractions using 0.1 M NaOH/0.4 M NaF mixtures produced better signals, which can even be improved by additional filtration using a 0.2mm membrane filter under pressure. Traditional wet chemical analyses of soil S using hydriodic acid (HI) reduction showed that the major proportion (98%) of total S was present in organic forms, out of which 77-84% were C-bonded S, whereas ester SO4 -S constituted merely 16-23% of the organic S pool in bulk soils. These values were constant regardless of major soil disturbances by landuse and did not change between different particle size fractions. S-XANES spectroscopy, however, showed clear differences of S oxidation states after environmental disturbance of soil and between physical soil separates making it a useful tool to assess S cycling in soil.

  14. Monitoring of sulfuric acid episodes in St. Louis, Missouri

    International Nuclear Information System (INIS)

    During July 1977 and again in February 1978 in St. Louis, Missouri, episodes of about 3-day duration occurred in which sulfuric acid persisted as part of the regional haze aerosol. These sulfuric acid episodes were monitored with 15-min time resolution by a thermal analysis--flame photometric detection particulate sulfur monitor. The measurement technique detects the concentration of total particulate sulfur as well as the fraction as H2SO4. However, it cannot distinguish between (NH4)2SO4 and NH4HSO4; thus it is not specific for the detection of total hydrogen ion concentration associated with particulate sulfur. In the summer, July--August 1977, total particulate sulfur average was 3.8 ?gS/m3, and the H2SO4 (measured as sulfur) average was below 0.5 ?gS/m3, while in the winter, February--March 1978, it was 3.2 and 0.8 ?gS/m3, respectively. During the summer episode the H2SO4 (as sulfur) peaked at about 10 ?gS/m3, compared to a total particulate sulfur peak concentration of 20 ?gS/m3. During the winter episode the H2SO4 concentration peaked at about 4 ?gS/m3, compared to a particulate sulfur peak concentration of 6 ?gS/m3. Daily average particulate sulfur and light scattering from July--August 1977 and February--March 1978 show a strong correlation (r>0.8). There were several general differences between the summer and winter data which suggest chemical and physical changes in the atmospheric aerosol. Analysis of the summer data revealed overall diurnal patterns in particulate sulfur and acidity, but these patterns did not show up with the winter data. The strong correlation between light scattering and particulate sulfur indicates that sulfur compounds play a prominent role in visibility degradation by fine particles

  15. Are we getting enough sulfur in our diet?

    Directory of Open Access Journals (Sweden)

    Han Bo

    2007-11-01

    Full Text Available Abstract Sulfur, after calcium and phosphorus, is the most abundant mineral element found in our body. It is available to us in our diets, derived almost exclusively from proteins, and yet only 2 of the 20 amino acids normally present in proteins contains sulfur. One of these amino acids, methionine, cannot be synthesized by our bodies and therefore has to be supplied by the diet. Cysteine, another sulfur containing amino acid, and a large number of key metabolic intermediates essential for life, are synthesized by us, but the process requires a steady supply of sulfur. Proteins contain between 3 and 6% of sulfur amino acids. A very small percentage of sulfur comes in the form of inorganic sulfates and other forms of organic sulfur present in foods such as garlic, onion, broccoli, etc. The minimal requirements (RDA for all the essential amino acids have always been estimated in terms of their ability to maintain a nitrogen balance. This method asses amino acid requirements for protein synthesis, only one of the pathways that methionine follows after ingestion. To adequately evaluate the RDA for methionine, one should perform, together with a nitrogen balance a sulfur balance, something never done, neither in humans nor animals. With this in mind we decided to evaluate the dietary intake of sulfur (as sulfur amino acids in a random population and perform sulfur balance studies in a limited number of human volunteers. Initially this was done to try and gain some information on the possible mode of action of a variety of sulfur containing compounds (chondroitin sulfate, glucosamine sulfate, and others, used as dietary supplements to treat diseases of the joints. Out of this study came information that suggested that a significant proportion of the population that included disproportionally the aged, may not be receiving sufficient sulfur and that these dietary supplements, were very likely exhibiting their pharmacological actions by supplying inorganic sulfur.

  16. Drinking Water Denitrification using Autotrophic Denitrifying Bacteria in a Fluidized Bed Bioreactor 

    Directory of Open Access Journals (Sweden)

    Abdolmotaleb Seid-mohammadi

    2013-02-01

    Full Text Available Background and Objectives: Contamination of drinking water sources with nitrate may cause adverse effects on human health. Due to operational and maintenance problems of physicochemical nitrate removal processes, using biological denitrification processes have been performed. The aim of this study is to evaluate nitrate removal efficiency from drinking water using autotrophic denitrifying bacteria immobilized on sulfur impregnated activated carbon in a fluidized bed bioreactor. Materials and Methods: After impregnating activated carbon by sulfur as a microorganism carriers and enrichment and inoculation of denitrifying bacteria, a laboratory-scale fluidized bed bioreactor was operated. Nitrate removal efficiency, nitrite, turbidity, hardness and TOC in the effluent were examined during the whole experiment under various conditions including constant influent nitrate concentration as 90 mg NO3--N/l corresponding to different HRT ranging from 5.53 to 1.5 hr. Results: We found that  the denitrification rates was depended on the hydraulic retention time and the nitrate removal efficiency was up to 98%  and nitrite concentration was lower than 1mg/l at optimum HRT=2.4 hr respectively. Moreover, there was no difference in hardness between influent and effluent due to supplying sodium bicarbonate as carbon source for denitrifying bacteria.  However pH, TOC, hardness, and turbidity of the effluent met the W.H.O guidelines for drinking water.  Conclusion: This study demonstrated that an innovative carrier as sulfur impregnated activated carbon could be used as both the biofilm carrier and energy source for treating nitrate contaminated drinking water in the lab-scale fluidized bed bioreactor.

  17. Green IT technologies and applications

    CERN Document Server

    Kim, Jae H

    2011-01-01

    This book is the first of its kind in presenting comprehensive technical issues and solutions for rapidly growing Green IT. It brings together in a single volume both green communications and green computing under the theme of Green IT, and presents exciting research and developments taking place therein in a survey style. Written by the subject matter experts consisting of an international team of recognized researchers and practitioners in the field, ""Green IT: Technologies and Applications"" will serve as an excellent source of information on the latest technical trend of Green IT for grad

  18. Green Logistics Management

    Science.gov (United States)

    Chang, Yoon S.; Oh, Chang H.

    Nowadays, environmental management becomes a critical business consideration for companies to survive from many regulations and tough business requirements. Most of world-leading companies are now aware that environment friendly technology and management are critical to the sustainable growth of the company. The environment market has seen continuous growth marking 532B in 2000, and 590B in 2004. This growth rate is expected to grow to 700B in 2010. It is not hard to see the environment-friendly efforts in almost all aspects of business operations. Such trends can be easily found in logistics area. Green logistics aims to make environmental friendly decisions throughout a product lifecycle. Therefore for the success of green logistics, it is critical to have real time tracking capability on the product throughout the product lifecycle and smart solution service architecture. In this chapter, we introduce an RFID based green logistics solution and service.

  19. Why Green Taxation

    DEFF Research Database (Denmark)

    HjØllund, Lene; Svendsen, Gert Tinggaard

    2001-01-01

    According to economists solving environmental problems is simple. Politicians should simply impose a uniform tax on harmful emissions. However, the actual design of such green taxation shows that politicians do not follow their advice. CO2 taxation in OECD, for example, is highly differentiated and much in favour of industry. In fact, CO2 tax rates for industry are, on average, six times lower than those for households. We argue that the reason for this tax differentiation is that industry, in contrast to households, has a strong capability to lobby. Therefore, green taxation is effectively blocked and the desired environmental results are not being achieved. Why then is green taxation persistently applied in relation to industry? We argue that strong fiscal incentives drive this policy choice at the expense of environmental concerns because it allows environmental bureaucracies to budget-maximize.

  20. Fuzzy species among recombinogenic bacteria

    Directory of Open Access Journals (Sweden)

    Fraser Christophe

    2005-03-01

    Full Text Available Abstract Background It is a matter of ongoing debate whether a universal species concept is possible for bacteria. Indeed, it is not clear whether closely related isolates of bacteria typically form discrete genotypic clusters that can be assigned as species. The most challenging test of whether species can be clearly delineated is provided by analysis of large populations of closely-related, highly recombinogenic, bacteria that colonise the same body site. We have used concatenated sequences of seven house-keeping loci from 770 strains of 11 named Neisseria species, and phylogenetic trees, to investigate whether genotypic clusters can be resolved among these recombinogenic bacteria and, if so, the extent to which they correspond to named species. Results Alleles at individual loci were widely distributed among the named species but this distorting effect of recombination was largely buffered by using concatenated sequences, which resolved clusters corresponding to the three species most numerous in the sample, N. meningitidis, N. lactamica and N. gonorrhoeae. A few isolates arose from the branch that separated N. meningitidis from N. lactamica leading us to describe these species as 'fuzzy'. Conclusion A multilocus approach using large samples of closely related isolates delineates species even in the highly recombinogenic human Neisseria where individual loci are inadequate for the task. This approach should be applied by taxonomists to large samples of other groups of closely-related bacteria, and especially to those where species delineation has historically been difficult, to determine whether genotypic clusters can be delineated, and to guide the definition of species.