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Sample records for spore-forming thermophilic sulfate-reducing

  1. Desulfotomaculum arcticum sp. nov., a novel spore-forming, moderately thermophilic, sulfate-reducing bacterium isolated from a permanently cold fjord sediment of Svalbard

    DEFF Research Database (Denmark)

    Vandieken, Verona; Knoblauch, Christian; Jørgensen, Bo Barker

    2006-01-01

    Strain 15T is a novel spore-forming, sulfate-reducing bacterium isolated from a permanently cold fjord sediment of Svalbard. Sulfate could be replaced by sulfite or thiosulfate. Hydrogen, formate, lactate, propionate, butyrate, hexanoate, methanol, ethanol, propanol, butanol, pyruvate, malate...

  2. Thermophilic Sulfate-Reducing Bacteria in Cold Marine Sediment

    DEFF Research Database (Denmark)

    ISAKSEN, MF; BAK, F.; JØRGENSEN, BB

    1994-01-01

    sulfate-reducing bacteria was detected. Time course experiments showed constant sulfate reduction rates at 4 degrees C and 30 degrees C, whereas the activity at 60 degrees C increased exponentially after a lag period of one day. Thermophilic, endospore-forming sulfate-reducing bacteria, designated strain...... C to search for presence of psychrophilic, mesophilic and thermophilic sulfate-reducing bacteria. Detectable activity was initially only in the mesophilic range, but after a lag phase sulfate reduction by thermophilic sulfate-reducing bacteria were observed. No distinct activity of psychrophilic...... P60, were isolated and characterized as Desulfotomaculum kuznetsovii. The temperature response of growth and respiration of strain P60 agreed well with the measured sulfate reduction at 50 degrees-70 degrees C. Bacteria similar to strain P60 could thus be responsible for the measured thermophilic...

  3. Thermophilic Sulfate-Reducing Bacteria in Cold Marine Sediment

    DEFF Research Database (Denmark)

    ISAKSEN, MF; BAK, F.; JØRGENSEN, BB

    1994-01-01

    C to search for presence of psychrophilic, mesophilic and thermophilic sulfate-reducing bacteria. Detectable activity was initially only in the mesophilic range, but after a lag phase sulfate reduction by thermophilic sulfate-reducing bacteria were observed. No distinct activity of psychrophilic...... sulfate-reducing bacteria was detected. Time course experiments showed constant sulfate reduction rates at 4 degrees C and 30 degrees C, whereas the activity at 60 degrees C increased exponentially after a lag period of one day. Thermophilic, endospore-forming sulfate-reducing bacteria, designated strain...... P60, were isolated and characterized as Desulfotomaculum kuznetsovii. The temperature response of growth and respiration of strain P60 agreed well with the measured sulfate reduction at 50 degrees-70 degrees C. Bacteria similar to strain P60 could thus be responsible for the measured thermophilic...

  4. Development of a Quantitative PCR Assay for Thermophilic Spore-Forming Geobacillus stearothermophilus in Canned Food.

    Science.gov (United States)

    Nakano, Miyo

    2015-01-01

    The thermophilic spore forming bacteria Geobacillus stearothermophilus is recognized as a major cause of spoilage in canned food. A quantitative real-time PCR assay was developed to specifically detect and quantify the species G. stearothermophilus in samples from canned food. The selected primer pairs amplified a 163-bp fragment of the 16S rRNA gene in a specific PCR assay with a detection limit of 12.5 fg of pure culture DNA, corresponding to DNA extracted from approximately 0.7 CFU/mL of G. stearothermophilus. Analysis showed that the bacterial species G. stearothermophilus was not detected in any canned food sample. Our approach presented here will be useful for tracking or quantifying species G. stearotethermophilus in canned food and ingredients.

  5. PCR detection of thermophilic spore-forming bacteria involved in canned food spoilage.

    Science.gov (United States)

    Prevost, S; Andre, S; Remize, F

    2010-12-01

    Thermophilic bacteria that form highly heat-resistant spores constitute an important group of spoilage bacteria of low-acid canned food. A PCR assay was developed in order to rapidly trace these bacteria. Three PCR primer pairs were designed from rRNA gene sequences. These primers were evaluated for the specificity and the sensitivity of detection. Two primer pairs allowed detection at the species level of Geobacillus stearothermophilus and Moorella thermoacetica/thermoautrophica. The other pair allowed group-specific detection of anaerobic thermophilic bacteria of the genera Thermoanaerobacterium, Thermoanaerobacter, Caldanerobium and Caldanaerobacter. After a single enrichment step, these PCR assays allowed the detection of 28 thermophiles from 34 cans of spoiled low-acid food. In addition, 13 ingredients were screened for the presence of these bacteria. This PCR assay serves as a detection method for strains able to spoil low-acid canned food treated at 55°C. It will lead to better reactivity in the canning industry. Raw materials and ingredients might be qualified not only for quantitative spore contamination, but also for qualitative contamination by highly heat-resistant spores.

  6. Hydrothermal vents in Lake Tanganyika harbor spore-forming thermophiles with extremely rapid growth

    DEFF Research Database (Denmark)

    Elsgaard, Lars; Prieur, Daniel

    2010-01-01

    A thermophilic anaerobic bacterium was isolated from a sublacustrine hydrothermal vent site in Lake Tanganyika (East Africa) with recorded fluid temperatures of 66–103 °C and pH values of 7.7–8.9. The bacterium (strain TR10) was rod-shaped, about 1 by 5 μm in size, and readily formed distal...... and peptone. The optimum temperature for growth was 60 °C, while minimum and maximum temperatures were 40 and 75 °C. The pH response was alkalitolerant with optimum pH at 7.4 and 8.5 depending on the growth medium. The distinct feature of rapid proliferation and endospore formation may allow the novel...

  7. Growth characteristics of thermophile sulfate-reducing bacteria and its effect on carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Liu, T.; Liu, H.; Hu, Y.; Zhou, L.; Zheng, B. [Department of Chemistry and Engineering, Huazhong University of Science and Technology, Wuhan (China)

    2009-03-15

    Sulfate-reducing bacteria (SRB) have been identified as the main corrosive microorganisms causing unpredictable failure of materials. In this present work, a strain of thermophile SRB isolated from Bohai oilfield of China has been characterized and preliminarily identified. Furthermore, its effects on carbon steel at 60 C in SRB culture media were studied by electrochemical methods such as potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), and weight loss measurements. The results show that the bacteria belong to Desulfotomaculum. The optimum growth temperature and pH of the bacteria were 60 C and 7.0, respectively. Weight loss measurements suggested that the corrosion rate of carbon steel in the culture media inoculated with thermophile SRB at 60 C was 2.2 times less than that at 37 C. At 60 C, SRB shifted the freely corroding potential of carbon steel toward a more positive value in the first 10 days, which later change to a negative value. Results obtained from potentiodynamic polarization and EIS were in good agreement. The changes in biofilm structure with increase in bacteria supply offers some kind of protection to the base material in the early culture days at 60 C. Subsequently, it accelerated corrosion. Energy dispersive spectrometry (EDS) and X-ray diffraction (XRD) methods indicate that corrosion products such as iron sulfides (FeS{sub x}) in biofilm play an important role in the biocorrosion process. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  8. Leaching and accumulation of trace elements in sulfate reducing granular sludge under concomitant thermophilic and low pH conditions

    NARCIS (Netherlands)

    Gonzalez-Gil, G.; Lopes, S.I.C.; Saikaly, P.E.; Lens, P.N.L.

    2012-01-01

    The leaching and/or accumulation of trace elements in sulfate reducing granular sludge systems was investigated. Two thermophilic up-flow anaerobic sludge bed (UASB) reactors operated at pH 5 were fed with sucrose (4 g COD l(reactor)(-1) d(-1)) and sulfate at different COD/SO42- ratios. During the

  9. Temperature-Dependent Alkyl Glycerol Ether Lipid Composition of Mesophilic and Thermophilic Sulfate-Reducing Bacteria

    Directory of Open Access Journals (Sweden)

    Arnauld Vinçon-Laugier

    2017-08-01

    Full Text Available The occurrence of non-isoprenoid alkyl glycerol ether lipids in Bacteria and natural environments is increasingly being reported and the specificity and diagenetic stability of these lipids make them powerful biomarkers for biogeochemical and environmental studies. Yet the environmental controls on the biosynthesis of these peculiar membrane lipids remain poorly documented. Here, the lipid content of two mesophilic (Desulfatibacillum aliphaticivorans and Desulfatibacillum alkenivorans and one thermophilic (Thermodesulfobacterium commune sulfate-reducing bacteria—whose membranes are mostly composed of ether lipids—was investigated as a function of growth temperature (20–40°C and 54–84°C, respectively. For all strains, the cellular lipid content was lower at sub- or supra-optimal growth temperature, but the relative proportions of dialkyl glycerols, monoalkyl glycerols and fatty acids remained remarkably stable whatever the growth temperature. Rather than changing the proportions of the different lipid classes, the three strains responded to temperature changes by modifying the average structural composition of the alkyl and acyl chains constitutive of their membrane lipids. Major adaptive mechanisms concerned modifications of the level of branching and of the proportions of the different methyl branched lipids. Specifically, an increase in temperature induced mesophilic strains to produce less dimethyl branched dialkyl glycerols and 10-methyl branched lipids relative to linear structures, and the thermophilic strain to decrease the proportion of anteiso relative to iso methyl branched compounds. These modifications were in agreement with a regulation of the membrane fluidity. In one mesophilic and the thermophilic strains, a modification of the growth temperature further induced changes in the relative proportions of sn-2 vs sn-1 monoalkyl glycerols, suggesting an unprecedented mechanism of homeoviscous adaptation in Bacteria. Strong

  10. Propensity for biofilm formation by aerobic mesophilic and thermophilic spore forming bacteria isolated from Chinese milk powders.

    Science.gov (United States)

    Sadiq, Faizan A; Flint, Steve; Yuan, Lei; Li, Yun; Liu, TongJie; He, GuoQing

    2017-12-04

    Biofilms on the surface of dairy manufacturing plants are potential reservoirs of microbial contamination. These microbial aggregates may harbour pathogenic and spoilage organisms which contaminate dairy products. The biofilm forming capacity of many spore forming isolates of dairy origin has not been given much attention. The present study explored the biofilm forming potential of 148 isolates, comprising mesophilic and thermophilic bacteria, with particular emphasis on Bacillus licheniformis on polystyrene and stainless steel (SS) surfaces. We concluded that only four species are of significance for biofilm development on the surface of SS in the presence of skimmed milk, namely, B. licheniformis, Geobacillus stearothermophilus, Geobacillus thermoleovorans group and Anoxybacillus flavithermus. The maximum number of cells recovered from the biofilms developed on SS coupons in the presence of skimmed milk for these four species was as follows: 4.8, 5.2, 4.5 and 5.3logCFU/cm 2 , respectively. Number of cells recovered from biofilms on 1cm 2 SS coupons increased in the presence of tryptic soy broth (TSB) for all mesophiles including B. licheniformis, while decreased for G. stearothermophilus, G. thermoleovorans group and A. flavithermus. The crystal violet staining assay on polystyrene proved to be inadequate to predict cell counts on SS for the bacteria tested in our trial in the presence of either TSB or skimmed milk. The results support the idea that biofilm formation is an important part of bacterial survival strategy as only the most prevalent isolates from milk powders formed good biofilms on SS in the presence of skimmed milk. Biofilm formation also proved to be a strain-dependent characteristic and interestingly significant variation in biofilm formation was observed within the same RAPD groups of B. licheniformis which supports the previously reported genetic and phenotypic heterogeneity within the same RAPD based groups. The work reported in this manuscript

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-01-01

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

  12. Complete genome sequence of the thermophilic sulfate-reducing ocean bacterium Thermodesulfatator indicus type strain (CIR29812(T)).

    Science.gov (United States)

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

    2012-05-25

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

  13. Spore-Forming Thermophilic Bacterium within Artificial Meteorite Survives Entry into the Earth's Atmosphere on FOTON-M4 Satellite Landing Module.

    Science.gov (United States)

    Slobodkin, Alexander; Gavrilov, Sergey; Ionov, Victor; Iliyin, Vyacheslav

    2015-01-01

    One of the key conditions of the lithopanspermia hypothesis is that microorganisms situated within meteorites could survive hypervelocity entry from space through the Earth's atmosphere. So far, all experimental proof of this possibility has been based on tests with sounding rockets which do not reach the transit velocities of natural meteorites. We explored the survival of the spore-forming thermophilic anaerobic bacterium, Thermoanaerobacter siderophilus, placed within 1.4-cm thick basalt discs fixed on the exterior of a space capsule (the METEORITE experiment on the FOTON-M4 satellite). After 45 days of orbital flight, the landing module of the space vehicle returned to Earth. The temperature during the atmospheric transit was high enough to melt the surface of basalt. T. siderophilus survived the entry; viable cells were recovered from 4 of 24 wells loaded with this microorganism. The identity of the strain was confirmed by 16S rRNA gene sequence and physiological tests. This is the first report on the survival of a lifeform within an artificial meteorite after entry from space orbit through Earth's atmosphere at a velocity that closely approached the velocities of natural meteorites. The characteristics of the artificial meteorite and the living object applied in this study can serve as positive controls in further experiments on testing of different organisms and conditions of interplanetary transport.

  14. Spore-Forming Thermophilic Bacterium within Artificial Meteorite Survives Entry into the Earth's Atmosphere on FOTON-M4 Satellite Landing Module.

    Directory of Open Access Journals (Sweden)

    Alexander Slobodkin

    Full Text Available One of the key conditions of the lithopanspermia hypothesis is that microorganisms situated within meteorites could survive hypervelocity entry from space through the Earth's atmosphere. So far, all experimental proof of this possibility has been based on tests with sounding rockets which do not reach the transit velocities of natural meteorites. We explored the survival of the spore-forming thermophilic anaerobic bacterium, Thermoanaerobacter siderophilus, placed within 1.4-cm thick basalt discs fixed on the exterior of a space capsule (the METEORITE experiment on the FOTON-M4 satellite. After 45 days of orbital flight, the landing module of the space vehicle returned to Earth. The temperature during the atmospheric transit was high enough to melt the surface of basalt. T. siderophilus survived the entry; viable cells were recovered from 4 of 24 wells loaded with this microorganism. The identity of the strain was confirmed by 16S rRNA gene sequence and physiological tests. This is the first report on the survival of a lifeform within an artificial meteorite after entry from space orbit through Earth's atmosphere at a velocity that closely approached the velocities of natural meteorites. The characteristics of the artificial meteorite and the living object applied in this study can serve as positive controls in further experiments on testing of different organisms and conditions of interplanetary transport.

  15. Desulfotomaculum arcticum sp nov., a novel spore-formin, moderately thermophilic, sulfate-reducing bacterium isolated from a permanently cold fjord sediment of Svalbard

    DEFF Research Database (Denmark)

    Vandieken, V.; Knoblauch, C.; Jørgensen, BB

    2006-01-01

    Strain 15 T is a novel spore-forming, sulfate-reducing bacterium isolated from a permanently cold fjord sediment of Svalbard. Sulfate could be replaced by sulfite or thiosulfate. Hydrogen, formate, lactate, propionate, butyrate, hexanoate, methanol, ethanol, propanol, butanol, pyruvate, malate, s...... related to Desulfotomaculum thermosapovorans MLF(T) (93-5% 16S rRNA gene sequence similarity). Strain 15 T represents a novel species, for which the name Desulfotomaculurn arcticum sp. nov. is proposed. The type strain is strain 15 T (=DSM 17038(T)=jCM 12923(T))....

  16. Thermotoga lettingae sp. nov. : a novel thermophilic, methanol-degrading bacterium isolated from a thermophilic anaerobic reactor

    NARCIS (Netherlands)

    Balk, M.; Weijma, J.; Stams, A.J.M.

    2002-01-01

    A novel, anaerobic, non-spore-forming, mobile, Gram-negative, thermophilic bacterium, strain TMO(T), was isolated from a thermophilic sulfate-reducing bioreactor operated at 65 degrees C with methanol as the sole substrate. The G C content of the DNA of strain TMO(T) was 39.2 molÐThe optimum pH,

  17. Leaching and accumulation of trace elements in sulfate reducing granular sludge under concomitant thermophilic and low pH conditions

    KAUST Repository

    Gonzalez-Gil, Graciela; Lopes, Sí lvia I C; Saikaly, Pascal; Lens, Piet Nl L

    2012-01-01

    The leaching and/or accumulation of trace elements in sulfate reducing granular sludge systems was investigated. Two thermophilic up-flow anaerobic sludge bed (UASB) reactors operated at pH 5 were fed with sucrose (4gCODl reactor -1d -1) and sulfate at different COD/SO 4 2- ratios. During the start-up of such acidogenic systems, an initial leaching of trace elements from the inoculum sludge occurred regardless of trace elements supplementation in the reactor influent. The granular sludge maintained the physical structure despite high Fe leaching. After start-up and nonetheless the acidic conditions, Co, Ni, Cu, Zn, Mo and Se were retained or accumulated by the sludge when added. Particularly, Ni and Co accumulated in the carbonates and exchangeable fractions ensuring potential bioavailability. Otherwise, the initial stock in the inoculum sludge sufficed to operate the process for nearly 1year without supplementation of trace elements and no significant sludge wash-out occurred. © 2012 Elsevier Ltd.

  18. Leaching and accumulation of trace elements in sulfate reducing granular sludge under concomitant thermophilic and low pH conditions

    KAUST Repository

    Gonzalez-Gil, Graciela

    2012-12-01

    The leaching and/or accumulation of trace elements in sulfate reducing granular sludge systems was investigated. Two thermophilic up-flow anaerobic sludge bed (UASB) reactors operated at pH 5 were fed with sucrose (4gCODl reactor -1d -1) and sulfate at different COD/SO 4 2- ratios. During the start-up of such acidogenic systems, an initial leaching of trace elements from the inoculum sludge occurred regardless of trace elements supplementation in the reactor influent. The granular sludge maintained the physical structure despite high Fe leaching. After start-up and nonetheless the acidic conditions, Co, Ni, Cu, Zn, Mo and Se were retained or accumulated by the sludge when added. Particularly, Ni and Co accumulated in the carbonates and exchangeable fractions ensuring potential bioavailability. Otherwise, the initial stock in the inoculum sludge sufficed to operate the process for nearly 1year without supplementation of trace elements and no significant sludge wash-out occurred. © 2012 Elsevier Ltd.

  19. Effect of NaCl on thermophilic (55°C) methanol degradation in sulfate reducing granular sludge reactors

    NARCIS (Netherlands)

    Vallero, M.V.G.; Hulshoff Pol, L.W.; Lettinga, G.; Lens, P.N.L.

    2003-01-01

    The effect of NaCl on thermophilic (55degreesC) methanol conversion in the presence of excess of sulfate (COD/SO42-=0.5) was investigated in two 6.5L lab-scale upflow anaerobic sludge bed reactors inoculated with granular sludge previously not adapted to NaCl
    The effect of NaCl on thermophilic

  20. Thermophilic spore-forming bacteria isolated from spoiled canned food and their heat resistance. Results of a French ten-year survey.

    Science.gov (United States)

    André, S; Zuber, F; Remize, F

    2013-07-15

    Thermal processing of Low Acid Canned Foods (LACF), which are safe and shelf-stable at ambient temperature for several years, results in heat inactivation of all vegetative microorganisms and the partial or total inactivation of spores. Good Manufacturing Hygienic Practices include stability tests for managing the pathogen risk related to surviving mesophilic bacterial spores. LACF are also often submitted to additional incubation conditions, typically 55 °C for 7 days, to monitor spoilage by thermophiles. In this study we identified the bacterial species responsible for non-stability after prolonged at 55 °C of incubation of LACF from 455 samples collected from 122 French canneries over 10 years. Bacteria were identified by microsequencing or a recent developed tool for group-specific PCR detection (SporeTraQ™). A single species was identified for 93% of examined samples. Three genera were responsible for more than 80% of all non-stability cases: mostly Moorella (36%) and Geobacillus (35%), and less frequently Thermoanaerobacterium (10%). The other most frequent bacterial genera identified were Bacillus, Thermoanaerobacter, Caldanaerobius, Anoxybacillus, Paenibacillus and Clostridium. Species frequency was dependent on food category, i.e. vegetables, ready-made meals containing meat, seafood or other recipes, products containing fatty duck, and related to the intensity of the thermal treatment applied in these food categories. The spore heat resistance parameters (D or δ and z values) from 36 strains isolated in this study were determined. Taken together, our results single out the species most suitable for use as indicators for thermal process settings. This extensively-documented survey of the species that cause non-stability at 55 °C in LACF will help canneries to improve the management of microbial contamination. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Long-term adaptation of methanol-fed thermophilic (55°C) sulfate-reducing reactors to NaCl

    NARCIS (Netherlands)

    Vallero, M.V.G.; Lettinga, G.; Lens, P.N.L.

    2003-01-01

    A laboratory-scale upflow anaerobic sludge bed (UASB) reactor was operated during 273 days at increasing NaCl concentrations (0.5-12.5 g NaCl l(-1)) to assess whether the stepwise addition of the salt NaCl results in the acclimation of that sludge. The 6.5-1 thermophilic (55 degreesC), sulfidogenic

  2. Efforts to identify spore forming bacillus

    Energy Technology Data Exchange (ETDEWEB)

    Zuleiha, M.S.; Hilmy, N. (National Atomic Energy Agency, Jakarta (Indonesia). Pasar Djumat Research Centre)

    1982-04-01

    Efforts to identify 47 species of radioresistant spore forming bacillus sp. isolated from locally produced medical devices have been carried out. The identifications was conducted using 19 kinds of biochemical tests and compared to species to bacillus subtilis W. T.; bacillus pumilus E 601 and bacillus sphaericus Csub(I)A. The results showed that bacillus sp. examined could be divided into 6 groups, i.e. bacillus cereus; bacillus subtilis; bacillus stearothermophylus; bacillus coagulans; bacillus sphaericus and bacillus circulans.

  3. Efforts to identify spore forming bacillus

    International Nuclear Information System (INIS)

    Zuleiha, M.S.; Hilmy, Nazly

    1982-01-01

    Efforts to identify 47 species of radioresistant spore forming bacillus sp. isolated from locally produced medical devices have been carried out. The identifications was conducted using 19 kinds of biochemical tests and compared to species to bacillus subtilis W. T.; bacillus pumilus E 601 and bacillus sphaericus Csub(I)A. The results showed that bacillus sp. examined could be divided into 6 groups, i.e. bacillus cereus; bacillus subtilis; bacillus stearothermophylus; bacillus coagulans; bacillus sphaericus and bacillus circulans. (author)

  4. Contamination pathways of spore-forming bacteria in a vegetable cannery.

    Science.gov (United States)

    Durand, Loïc; Planchon, Stella; Guinebretiere, Marie-Hélène; André, Stéphane; Carlin, Frédéric; Remize, Fabienne

    2015-06-02

    Spoilage of low-acid canned food during prolonged storage at high temperatures is caused by heat resistant thermophilic spores of strict or facultative bacteria. Here, we performed a bacterial survey over two consecutive years on the processing line of a French company manufacturing canned mixed green peas and carrots. In total, 341 samples were collected, including raw vegetables, green peas and carrots at different steps of processing, cover brine, and process environment samples. Thermophilic and highly-heat-resistant thermophilic spores growing anaerobically were counted. During vegetable preparation, anaerobic spore counts were significantly decreased, and tended to remain unchanged further downstream in the process. Large variation of spore levels in products immediately before the sterilization process could be explained by occasionally high spore levels on surfaces and in debris of vegetable combined with long residence times in conditions suitable for growth and sporulation. Vegetable processing was also associated with an increase in the prevalence of highly-heat-resistant species, probably due to cross-contamination of peas via blanching water. Geobacillus stearothermophilus M13-PCR genotypic profiling on 112 isolates determined 23 profile-types and confirmed process-driven cross-contamination. Taken together, these findings clarify the scheme of contamination pathway by thermophilic spore-forming bacteria in a vegetable cannery. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Discrimination of Spore-Forming Bacilli Using spoIVA

    Science.gov (United States)

    Venkateswaran, Kasthuri; LaDuc, Myron; Stuecker, Tara

    2009-01-01

    A method of discriminating between spore-forming and non-spore-forming bacteria is based on a combination of simultaneous sporulation-specific and non-sporulation-specific quantitative polymerase chain reactions (Q-PCRs). The method was invented partly in response to the observation that for the purposes of preventing or reducing biological contamination affecting many human endeavors, ultimately, only the spore-forming portions of bacterial populations are the ones that are problematic (or, at least, more problematic than are the non-spore-forming portions). In some environments, spore-forming bacteria constitute small fractions of the total bacterial populations. The use of sporulation-specific primers in Q-PCR affords the ability to assess the spore-forming fraction of a bacterial population present in an environment of interest. This assessment can provide a more thorough and accurate understanding of the bacterial contamination in the environment, thereby making it possible to focus contamination- testing, contamination-prevention, sterilization, and decontamination resources more economically and efficiently. The method includes the use of sporulation-specific primers in the form of designed, optimized deoxyribonucleic acid (DNA) oligonucleotides specific for the bacterial spoIVA gene (see table). [In "spoIVA," "IV" signifies Roman numeral four and the entire quoted name refers to gene A for the fourth stage of sporulation.] These primers are mixed into a PCR cocktail with a given sample of bacterial cells. A control PCR cocktail into which are mixed universal 16S rRNA primers is also prepared. ["16S rRNA" denotes a ribosomal ribonucleic acid (rRNA) sequence that is common to all organisms.] Following several cycles of heating and cooling according to the PCR protocol to amplify amounts of DNA molecules, the amplification products can be analyzed to determine the types of bacterial cells present within the samples. If the amplification product is strong

  6. Draft Genome Sequence of the Sulfate-Reducing Bacterium Desulfotomaculum copahuensis Strain CINDEFI1 Isolated from the Geothermal Copahue System, Neuqu?n, Argentina

    OpenAIRE

    Willis Poratti, Graciana; Yaakop, Amira Suriaty; Chan, Chia Sing; Urbieta, M. Sof?a; Chan, Kok-Gan; Ee, Robson; Tan-Guan-Sheng, Adrian; Goh, Kian Mau; Donati, Edgardo R.

    2016-01-01

    Desulfotomaculum copahuensis strain CINDEFI1 is a novel spore-forming sulfate-reducing bacterium isolated from the Copahue volcano area, Argentina. Here, we present its draft genome in which we found genes related with the anaerobic respiration of sulfur compounds similar to those present in the Copahue environment.

  7. Draft Genome Sequence of the Sulfate-Reducing Bacterium Desulfotomaculum copahuensis Strain CINDEFI1 Isolated from the Geothermal Copahue System, Neuquén, Argentina.

    Science.gov (United States)

    Willis Poratti, Graciana; Yaakop, Amira Suriaty; Chan, Chia Sing; Urbieta, M Sofía; Chan, Kok-Gan; Ee, Robson; Tan-Guan-Sheng, Adrian; Goh, Kian Mau; Donati, Edgardo R

    2016-08-18

    Desulfotomaculum copahuensis strain CINDEFI1 is a novel spore-forming sulfate-reducing bacterium isolated from the Copahue volcano area, Argentina. Here, we present its draft genome in which we found genes related with the anaerobic respiration of sulfur compounds similar to those present in the Copahue environment. Copyright © 2016 Willis Poratti et al.

  8. Bactericide for sulfate-reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Shklyar, T F; Anoshina, G M; Blokhin, V Ye; Kisarrev, Ye L; Novikovsa, G M

    1981-01-01

    The aim of the invention is to find a bactericide for sulfate-reducing bacteria of oil fields in Western Siberia in order to suppress the biocorrosive activity on oil industry equipment. This goal is achieved by using M-nitroacetanylide as the bactericide of sulfate-reducing bacteria. This agent suppresses the activity of a stored culture of sulfate-reducing bacteria that comes from industrial waste waters injection wells of the Smotlor oil field.

  9. DNA fingerprinting of spore-forming bacterial isolates, using Bacillus ...

    African Journals Online (AJOL)

    Bc-repetitive extragenic palindromic polymerase chain reaction (Bc-Rep PCR) analysis was conducted on seven Bacillus thuringiensis isolates accessed from the Deutsche Sammlung von Mikroorganismen und Zellkulturen (DSMZ) culture collection and on five local isolates of entomopathogenic spore-forming bacteria.

  10. Methanol utilizing Desulfotomaculum species utilizes hydrogen in a methanol-fed sulfate-reducing bioreactor

    NARCIS (Netherlands)

    Balk, M.; Weijma, J.; Goorissen, H.P.; Ronteltap, M.; Hansen, T.A.; Stams, A.J.M.

    2007-01-01

    A sulfate-reducing bacterium, strain WW1, was isolated from a thermophilic bioreactor operated at 65 degrees C with methanol as sole energy source in the presence of sulfate. Growth of strain WW1 on methanol or acetate was inhibited at a sulfide concentration of 200 mg l(-1), while on H-2/CO2, no

  11. Desulfotomaculum spp. and related Gram-positive sulfate-reducing bacteria in deep subsurface environments.

    Directory of Open Access Journals (Sweden)

    Thomas eAullo

    2013-12-01

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

  12. Biocidal Energetic Materials for the Destruction of Spore Forming Bacteria

    Science.gov (United States)

    2015-07-01

    agent (GA). During a reaction the GA generates nucleation sites that promote the formation of bubbles. As the reaction wave passes, the gas pockets...studies have shown iodine producing reactive materials are effective against spore forming bacteria, but are sensitive to the relative humidity in the...testing environment. Results from tests run in relative high humidity environments show a decreased ability of iodine to effectively neutralize

  13. Microbial enhanced heavy oil recovery by the aid of inhabitant spore-forming bacteria: an insight review.

    Science.gov (United States)

    Shibulal, Biji; Al-Bahry, Saif N; Al-Wahaibi, Yahya M; Elshafie, Abdulkader E; Al-Bemani, Ali S; Joshi, Sanket J

    2014-01-01

    Crude oil is the major source of energy worldwide being exploited as a source of economy, including Oman. As the price of crude oil increases and crude oil reserves collapse, exploitation of oil resources in mature reservoirs is essential for meeting future energy demands. As conventional recovery methods currently used have become less efficient for the needs, there is a continuous demand of developing a new technology which helps in the upgradation of heavy crude oil. Microbial enhanced oil recovery (MEOR) is an important tertiary oil recovery method which is cost-effective and eco-friendly technology to drive the residual oil trapped in the reservoirs. The potential of microorganisms to degrade heavy crude oil to reduce viscosity is considered to be very effective in MEOR. Earlier studies of MEOR (1950s) were based on three broad areas: injection, dispersion, and propagation of microorganisms in petroleum reservoirs; selective degradation of oil components to improve flow characteristics; and production of metabolites by microorganisms and their effects. Since thermophilic spore-forming bacteria can thrive in very extreme conditions in oil reservoirs, they are the most suitable organisms for the purpose. This paper contains the review of work done with thermophilic spore-forming bacteria by different researchers.

  14. Microbial Enhanced Heavy Oil Recovery by the Aid of Inhabitant Spore-Forming Bacteria: An Insight Review

    Directory of Open Access Journals (Sweden)

    Biji Shibulal

    2014-01-01

    Full Text Available Crude oil is the major source of energy worldwide being exploited as a source of economy, including Oman. As the price of crude oil increases and crude oil reserves collapse, exploitation of oil resources in mature reservoirs is essential for meeting future energy demands. As conventional recovery methods currently used have become less efficient for the needs, there is a continuous demand of developing a new technology which helps in the upgradation of heavy crude oil. Microbial enhanced oil recovery (MEOR is an important tertiary oil recovery method which is cost-effective and eco-friendly technology to drive the residual oil trapped in the reservoirs. The potential of microorganisms to degrade heavy crude oil to reduce viscosity is considered to be very effective in MEOR. Earlier studies of MEOR (1950s were based on three broad areas: injection, dispersion, and propagation of microorganisms in petroleum reservoirs; selective degradation of oil components to improve flow characteristics; and production of metabolites by microorganisms and their effects. Since thermophilic spore-forming bacteria can thrive in very extreme conditions in oil reservoirs, they are the most suitable organisms for the purpose. This paper contains the review of work done with thermophilic spore-forming bacteria by different researchers.

  15. Sulfate reducing potential in an estuarine beach

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.; Chandramohan, D.

    Sulfate reducing bacteria (SRB) and their activity (SRA) together with total anaerobic and aerobic bacterial flora were estimated during July 1982-April 1983 and July-August 1984 from 1, 3 and 5 cm depths using core samples. The average number (no...

  16. Handling technique of spore-forming bacteria in radiation sterilization. 1. Preparation of spores

    International Nuclear Information System (INIS)

    Koshikawa, Tomihiko

    1994-01-01

    This paper deals with a handling technique of spore-forming bacteria in radiation sterilization. An explanation is given under three sections: (1) life cycle of spore-forming bacteria, medium to form bacterial spores, and colony and purification methods of bacterial spores; (2) methods for measuring the number of bacterial spores and resistance against gamma radiation (D values); and (3) a test method for identifying spore-forming bacteria and a simple identification method. (N.K.)

  17. Mechanisms and Effectivity of Sulfate Reducing Bioreactors ...

    Science.gov (United States)

    Mining-influenced water (MIW) is the main environmental challenges associated with the mining industry. Passive MIW remediation can be achieved through microbial activity in sulfate-reducing bioreactors (SRBRs), but their actual removal rates depend on different factors, one of which is the substrate composition. Chitinous materials have demonstrated high metal removal rates, particularly for the two recalcitrant MIW contaminants Zn and Mn, but their removal mechanisms need further study. We studied Cd, Fe, Zn, and Mn removal in bioactive and abiotic SRBRs to elucidate the metal removal mechanisms and the differences in metal and sulfate removal rates using a chitinous material as substrate. We found that sulfate-reducing bacteria are effective in increasing metal and sulfate removal rates and duration of operation in SRBRs, and that the main mechanism involved was metal precipitation as sulfides. The solid residues provided evidence of the presence of sulfides in the bioactive column, more specifically ZnS, according to XPS analysis. The feasibility of passive treatments with a chitinous substrate could be an important option for MIW remediation. Mining influenced water (MIW) remediation is still one of the top priorities for the agency because it addresses the most important environmental problem associated with the mining industry and that affects thousands of communities in the U.S. and worldwide. In this paper, the MIW bioremediation mechanisms are studied

  18. Molecular Characterization of Sulfate-Reducing Bacteria in the Guaymas Basin†

    Science.gov (United States)

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

    2003-01-01

    The Guaymas Basin (Gulf of California) is a hydrothermal vent site where thermal alteration of deposited planktonic and terrestrial organic matter forms petroliferous material which supports diverse sulfate-reducing bacteria. We explored the phylogenetic and functional diversity of the sulfate-reducing bacteria by characterizing PCR-amplified dissimilatory sulfite reductase (dsrAB) and 16S rRNA genes from the upper 4 cm of the Guaymas sediment. The dsrAB sequences revealed that there was a major clade closely related to the acetate-oxidizing delta-proteobacterial genus Desulfobacter and a clade of novel, deeply branching dsr sequences related to environmental dsr sequences from marine sediments in Aarhus Bay and Kysing Fjord (Denmark). Other dsr clones were affiliated with gram-positive thermophilic sulfate reducers (genus Desulfotomaculum) and the delta-proteobacterial species Desulforhabdus amnigena and Thermodesulforhabdus norvegica. Phylogenetic analysis of 16S rRNAs from the same environmental samples resulted in identification of four clones affiliated with Desulfobacterium niacini, a member of the acetate-oxidizing, nutritionally versatile genus Desulfobacterium, and one clone related to Desulfobacula toluolica and Desulfotignum balticum. Other bacterial 16S rRNA bacterial phylotypes were represented by non-sulfate reducers and uncultured lineages with unknown physiology, like OP9, OP8, as well as a group with no clear affiliation. In summary, analyses of both 16S rRNA and dsrAB clone libraries resulted in identification of members of the Desulfobacteriales in the Guaymas sediments. In addition, the dsrAB sequencing approach revealed a novel group of sulfate-reducing prokaryotes that could not be identified by 16S rRNA sequencing. PMID:12732547

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

    Science.gov (United States)

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

    2003-01-01

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

  20. Monitoring sulfide and sulfate-reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, R.S.

    1995-12-31

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

  1. Metabolic Flexibility of Sulfate Reducing Bacteria

    Directory of Open Access Journals (Sweden)

    Caroline M. Plugge

    2011-05-01

    Full Text Available Dissimilatory sulfate-reducing prokaryotes (SRB are a very diverse group of anaerobic bacteria that are omnipresent in nature and play an imperative role in the global cycling of carbon and sulfur. In anoxic marine sediments sulfate reduction accounts for up to 50% of the entire organic mineralization in coastal and shelf ecosystems where sulfate diffuses several meters deep into the sediment. As a consequence, SRB would be expected in the sulfate-containing upper sediment layers, whereas methanogenic Archaea would be expected to succeed in the deeper sulfate-depleted layers of the sediment. Where sediments are high in organic matter, sulfate is depleted at shallow sediment depths, and biogenic methane production will occur. In the absence of sulfate, many SRB ferment organic acids and alcohols, producing hydrogen, acetate, and carbon dioxide, and may even rely on hydrogen- and acetate-scavenging methanogens to convert organic compounds to methane. SRB can establish two different life styles, and these can be termed as sulfidogenic and acetogenic, hydrogenogenic metabolism. The advantage of having different metabolic capabilities is that it raises the chance of survival in environments when electron acceptors become depleted. In marine sediments, SRB and methanogens do not compete but rather complement each other in the degradation of organic matter.Also in freshwater ecosystems with sulfate concentrations of only 10-200 μM, sulfate is consumed efficiently within the top several cm of the sediments. Here, many of the δ-Proteobacteria present have the genetic machinery to perform dissimilatory sulfate reduction, yet they have an acetogenic, hydrogenogenic way of life.In this review we evaluate the physiology and metabolic mode of SRB in relation with their environment.

  2. Sulfate Transporters in Dissimilatory Sulfate Reducing Microorganisms: A Comparative Genomics Analysis

    Directory of Open Access Journals (Sweden)

    Angeliki Marietou

    2018-03-01

    Full Text Available The first step in the sulfate reduction pathway is the transport of sulfate across the cell membrane. This uptake has a major effect on sulfate reduction rates. Much of the information available on sulfate transport was obtained by studies on assimilatory sulfate reduction, where sulfate transporters were identified among several types of protein families. Despite our growing knowledge on the physiology of dissimilatory sulfate-reducing microorganisms (SRM there are no studies identifying the proteins involved in sulfate uptake in members of this ecologically important group of anaerobes. We surveyed the complete genomes of 44 sulfate-reducing bacteria and archaea across six phyla and identified putative sulfate transporter encoding genes from four out of the five surveyed protein families based on homology. We did not find evidence that ABC-type transporters (SulT are involved in the uptake of sulfate in SRM. We speculate that members of the CysP sulfate transporters could play a key role in the uptake of sulfate in thermophilic SRM. Putative CysZ-type sulfate transporters were present in all genomes examined suggesting that this overlooked group of sulfate transporters might play a role in sulfate transport in dissimilatory sulfate reducers alongside SulP. Our in silico analysis highlights several targets for further molecular studies in order to understand this key step in the metabolism of SRMs.

  3. Growth of sulfate reducers in deep-subseafloor sediments stimulated by crustal fluids

    Directory of Open Access Journals (Sweden)

    Katja eFichtel

    2012-02-01

    Full Text Available On a global scale, crustal fluids fuel a substantial part of the deep subseafloor biosphere by providing electron acceptors for microbial respiration. In this study, we examined bacterial cultures from a sediment column of the Juan de Fuca Ridge, Northeast Pacific (IODP Site U1301 which is divided into three distinctive compartments: an upper sulfate-containing zone, formed by bottom-seawater diffusion, a sulfate-depleted zone and a second (~140 m thick sulfate-containing zone influenced by fluid diffusion from the basaltic aquifer. Sulfate reducers were isolated from near-surface and near-basement sediments. All initial enrichments harboured specific communities of heterotrophic microorganisms. Among those, the number of isolated spore-forming Firmicutes decreased from 60% to 21% with sediment depth. Strains affiliated to Desulfosporosinus lacus, Desulfotomaculum sp. and Desulfovibrio aespoeensis were recovered from the upper sediment layers (1.3-9.1 meters below seafloor, mbsf. Several strains of Desulfovibrio indonesiensis and one relative of Desulfotignum balticum were isolated from near-basement sediments (240-262 mbsf. The physiological investigation of strains affiliated to D. aespoeensis, D. indonesiensis and D. balticum indicated that they were all able to use sulfate, thiosulfate and sulfite as electron acceptors. In the presence of sulfate, they grew strain-specifically on a few short-chain n-alcohols and fatty acids, only. The strains fermented either ethanol, pyruvate or betaine. Interestingly, all strains utilized hydrogen and the isolate affiliated to D. indonesiensis even exhibited an autotrophic life-mode. Thus, in the deep subseafloor where organic substrates are limited or hardly degradable, hydrogen might become an essential electron donor. The isolation of non-sporeforming sulfate reducers from fluid-influenced layers indicates that they have survived the long-term burial as active populations even after the separation from

  4. Metabolic interactions in methanogenic and sulfate-reducing bioreactors.

    Science.gov (United States)

    Stams, A J M; Plugge, C M; de Bok, F A M; van Houten, B H G W; Lens, P; Dijkman, H; Weijma, J

    2005-01-01

    In environments where the amount of electron acceptors is insufficient for complete breakdown of organic matter, methane is formed as the major reduced end product. In such methanogenic environments organic acids are degraded by syntrophic consortia of acetogenic bacteria and methanogenic archaea. Hydrogen consumption by methanogens is essential for acetogenic bacteria to convert organic acids to acetate and hydrogen. Several syntrophic cocultures growing on propionate and butyrate have been described. These syntrophic fatty acid-degrading consortia are affected by the presence of sulfate. When sulfate is present sulfate-reducing bacteria compete with methanogenic archaea for hydrogen and acetate, and with acetogenic bacteria for propionate and butyrate. Sulfate-reducing bacteria easily outcompete methanogens for hydrogen, but the presence of acetate as carbon source may influence the outcome of the competition. By contrast, acetoclastic methanogens can compete reasonably well with acetate-degrading sulfate reducers. Sulfate-reducing bacteria grow much faster on propionate and butyrate than syntrophic consortia.

  5. Structure, diversity and evolution of protein toxins from spore-forming entomopathogenic bacteria

    NARCIS (Netherlands)

    Maagd, de R.A.; Bravo, A.; Berry, C.; Crickmore, N.; Schnepf, H.E.

    2003-01-01

    Gram-positive spore-forming entomopathogenic bacteria can utilize a large variety of protein toxins to help them invade, infect, and finally kill their hosts, through their action on the insect midgut. These toxins belong to a number of homology groups containing a diversity of protein structures

  6. Active sulfur cycling by diverse mesophilic and thermophilic microorganisms in terrestrial mud volcanoes of Azerbaijan.

    Science.gov (United States)

    Green-Saxena, A; Feyzullayev, A; Hubert, C R J; Kallmeyer, J; Krueger, M; Sauer, P; Schulz, H-M; Orphan, V J

    2012-12-01

    Terrestrial mud volcanoes (TMVs) represent geochemically diverse habitats with varying sulfur sources and yet sulfur cycling in these environments remains largely unexplored. Here we characterized the sulfur-metabolizing microorganisms and activity in four TMVs in Azerbaijan. A combination of geochemical analyses, biological rate measurements and molecular diversity surveys (targeting metabolic genes aprA and dsrA and SSU ribosomal RNA) supported the presence of active sulfur-oxidizing and sulfate-reducing guilds in all four TMVs across a range of physiochemical conditions, with diversity of these guilds being unique to each TMV. The TMVs varied in potential sulfate reduction rates (SRR) by up to four orders of magnitude with highest SRR observed in sediments where in situ sulfate concentrations were highest. Maximum temperatures at which SRR were measured was 60°C in two TMVs. Corresponding with these trends in SRR, members of the potentially thermophilic, spore-forming, Desulfotomaculum were detected in these TMVs by targeted 16S rRNA analysis. Additional sulfate-reducing bacterial lineages included members of the Desulfobacteraceae and Desulfobulbaceae detected by aprA and dsrA analyses and likely contributing to the mesophilic SRR measured. Phylotypes affiliated with sulfide-oxidizing Gamma- and Betaproteobacteria were abundant in aprA libraries from low sulfate TMVs, while the highest sulfate TMV harboured 16S rRNA phylotypes associated with sulfur-oxidizing Epsilonproteobacteria. Altogether, the biogeochemical and microbiological data indicate these unique terrestrial habitats support diverse active sulfur-cycling microorganisms reflecting the in situ geochemical environment. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  7. The deep-subsurface sulfate reducer Desulfotomaculum kuznetsovii employs two methanol-degrading pathways.

    Science.gov (United States)

    Sousa, Diana Z; Visser, Michael; van Gelder, Antonie H; Boeren, Sjef; Pieterse, Mervin M; Pinkse, Martijn W H; Verhaert, Peter D E M; Vogt, Carsten; Franke, Steffi; Kümmel, Steffen; Stams, Alfons J M

    2018-01-16

    Methanol is generally metabolized through a pathway initiated by a cobalamine-containing methanol methyltransferase by anaerobic methylotrophs (such as methanogens and acetogens), or through oxidation to formaldehyde using a methanol dehydrogenase by aerobes. Methanol is an important substrate in deep-subsurface environments, where thermophilic sulfate-reducing bacteria of the genus Desulfotomaculum have key roles. Here, we study the methanol metabolism of Desulfotomaculum kuznetsovii strain 17 T , isolated from a 3000-m deep geothermal water reservoir. We use proteomics to analyze cells grown with methanol and sulfate in the presence and absence of cobalt and vitamin B12. The results indicate the presence of two methanol-degrading pathways in D. kuznetsovii, a cobalt-dependent methanol methyltransferase and a cobalt-independent methanol dehydrogenase, which is further confirmed by stable isotope fractionation. This is the first report of a microorganism utilizing two distinct methanol conversion pathways. We hypothesize that this gives D. kuznetsovii a competitive advantage in its natural environment.

  8. Methanol utilizing Desulfotomaculum species utilizes hydrogen in a methanol-fed sulfate-reducing bioreactor.

    Science.gov (United States)

    Balk, Melike; Weijma, Jan; Goorissen, Heleen P; Ronteltap, Mariska; Hansen, Theo A; Stams, Alfons J M

    2007-01-01

    A sulfate-reducing bacterium, strain WW1, was isolated from a thermophilic bioreactor operated at 65 degrees C with methanol as sole energy source in the presence of sulfate. Growth of strain WW1 on methanol or acetate was inhibited at a sulfide concentration of 200 mg l(-1), while on H2/CO2, no apparent inhibition occurred up to a concentration of 500 mg l(-1). When strain WW1 was co-cultured under the same conditions with the methanol-utilizing, non-sulfate-reducing bacteria, Thermotoga lettingae and Moorella mulderi, both originating from the same bioreactor, growth and sulfide formation were observed up to 430 mg l(-1). These results indicated that in the co-cultures, a major part of the electron flow was directed from methanol via H2/CO2 to the reduction of sulfate to sulfide. Besides methanol, acetate, and hydrogen, strain WW1 was also able to use formate, malate, fumarate, propionate, succinate, butyrate, ethanol, propanol, butanol, isobutanol, with concomitant reduction of sulfate to sulfide. In the absence of sulfate, strain WW1 grew only on pyruvate and lactate. On the basis of 16S rRNA analysis, strain WW1 was most closely related to Desulfotomaculum thermocisternum and Desulfotomaculum australicum. However, physiological properties of strain WW1 differed in some aspects from those of the two related bacteria.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-03-15

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

  10. Hygiene Aspects of the Biogas Process with Emphasis on Spore-Forming Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Bagge, Elisabeth

    2009-07-01

    Biogas is a renewable source of energy which can be obtained from processing of biowaste. The digested residues can be used as fertiliser. Biowaste intended for biogas production contains pathogenic micro-organisms. A pre-pasteurisation step at 70 deg C for 60 min before anaerobic digestion reduces non spore-forming bacteria such as Salmonella spp. To maintain the standard of the digested residues it must be handled in a strictly hygienic manner to avoid recontamination and re-growth of bacteria. The risk of contamination is particularly high when digested residues are transported in the same vehicles as the raw material. However, heat treatment at 70 deg C for 60 min will not reduce spore-forming bacteria such as Bacillus spp. and Clostridium spp. Spore-forming bacteria, including those that cause serious diseases, can be present in substrate intended for biogas production. The number of species and the quantity of Bacillus spp. and Clostridium spp. in manure, slaughterhouse waste and in samples from different stages during the biogas process were investigated. The number of species of clostridia seemed to decrease following digestion, likewise the quantity. However, Bacillus spp. seemed to pass unaffected through the biogas process. In laboratory-scale experiments the effects on clostridia during pasteurisation and digestion were investigated. Pathogenic clostridia were inoculated in substrates from homogenisation tanks and digester tanks. The inoculated clostridia remained after pasteurisation, but the impacts of digestion differ between different species. Culture followed by identification of C. chauvoei by PCR in samples from cattle died from blackleg, is faster and safer than culture followed by biochemical identification of C. chauvoei. However, for environmental samples the PCR method is not practically applicable for detection of C. chauvoei. To avoid spreading of diseases via biogas plants when digested residues are spread on arable land, a pasteurisation

  11. Transformation of carbon tetrachloride under sulfate reducing conditions

    NARCIS (Netherlands)

    Best, Jappe H. de; Salminen, E.; Doddema, Hans J.; Janssen, Dick B.; Harder, Wim

    1998-01-01

    The removal of carbon tetrachloride under sulfate reducing conditions was studied in an anaerobic packed-bed reactor. Carbon tetrachloride, up to a concentration of 30 µM, was completely converted. Chloroform and dichloromethane were the main transformation products, but part of the carbon

  12. Transformation of carbon tetrachloride under sulfate reducing conditions

    NARCIS (Netherlands)

    de Best, JH; Salminen, E; Doddema, HJ; Janssen, DB; Harder, W

    1997-01-01

    The removal of carbon tetrachloride under sulfate reducing conditions was studied in an anaerobic packed-bed reactor. Carbon tetrachloride, up to a concentration of 30 mu M, was completely converted. Chloroform and dichloromethane were the main transformation products, but part of the carbon

  13. Remediation of Acid Mine Drainage with Sulfate Reducing Bacteria

    Science.gov (United States)

    Hauri, James F.; Schaider, Laurel A.

    2009-01-01

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

  14. Mercury and lead tolerance in hypersaline sulfate-reducing bacteria

    Digital Repository Service at National Institute of Oceanography (India)

    Harithsa, S.; Kerkar, S.; LokaBharathi, P.A.

    -sporulating, non-motile rods lacking in desulfoviridin and cytochromes. Examination of these isolates for heavy metal tolerance and response studies in terms of growth and sulfate-reducing activity (SRA) were carried out using HgCl sub(2) and Pb(NO sub(3)) sub(2...

  15. Localized sulfate-reducing zones in a coastal plain aquifer

    Science.gov (United States)

    Brown, C.J.; Coates, J.D.; Schoonen, M.A.A.

    1999-01-01

    High concentrations of dissolved iron in ground water of coastal plain or alluvial aquifers contribute to the biofouling of public supply wells for which treatment and remediation is costly. Many of these aquifers, however, contain zones in which microbial sulfate reduction and the associated precipitation of iron-sulfide minerals decreases iron mobility. The principal water-bearing aquifer (Magothy Aquifer of Cretaceous age) in Suffolk County, New York, contains localized sulfate-reducing zones in and near lignite deposits, which generally are associated with clay lenses. Microbial analyses of core samples amended with [14C]-acetate indicate that microbial sulfate reduction is the predominant terminal-electron-accepting process (TEAP) in poorly permeable, lignite-rich sediments at shallow depths and near the ground water divide. The sulfate-reducing zones are characterized by abundant lignite and iron-sulfide minerals, low concentrations of Fe(III) oxyhydroxides, and by proximity to clay lenses that contain pore water with relatively high concentrations of sulfate and dissolved organic carbon. The low permeability of these zones and, hence, the long residence time of ground water within them, permit the preservation and (or) allow the formation of iron-sulfide minerals, including pyrite and marcasite. Both sulfate-reducing bacteria (SRB) and iron-reducing bacteria (IRB) are present beneath and beyond the shallow sulfate-reducing zones. A unique Fe(III)-reducing organism, MD-612, was found in core sediments from a depth of 187 m near the southern shore of Long Island. The distribution of poorly permeable, lignite-rich, sulfate-reducing zones with decreased iron concentration is varied within the principal aquifer and accounts for the observed distribution of dissolved sulfate, iron, and iron sulfides in the aquifer. Locating such zones for the placement of production wells would be difficult, however, because these zones are of limited aerial extent.

  16. Acid and bile tolerance of spore-forming lactic acid bacteria.

    Science.gov (United States)

    Hyronimus, B; Le Marrec, C; Sassi, A H; Deschamps, A

    2000-11-01

    Criteria for screening probiotics such as bile tolerance and resistance to acids were studied with 13 spore-forming lactic acid producing bacteria. Different strains of Sporolactobacillus, Bacillus laevolacticus, Bacillus racemilacticus and Bacillus coagulans grown in MRS broth were subjected to low pH conditions (2, 2.5 and 3) and increasing bile concentrations. Among these microorganisms, Bacillus laevolacticus DSM 6475 and all Sporolactobacillus strains tested except Sporolactobacillus racemicus IAM 12395, were resistant to pH 3. Only Bacillus racemilacticus and Bacillus coagulans strains were tolerant to bile concentrations over 0.3% (w/v).

  17. Diversity of sulfur isotope fractionations by sulfate-reducing prokaryotes

    DEFF Research Database (Denmark)

    Detmers, Jan; Brüchert, Volker; Habicht, K S

    2001-01-01

    Batch culture experiments were performed with 32 different sulfate-reducing prokaryotes to explore the diversity in sulfur isotope fractionation during dissimilatory sulfate reduction by pure cultures. The selected strains reflect the phylogenetic and physiologic diversity of presently known...... sulfate reducers and cover a broad range of natural marine and freshwater habitats. Experimental conditions were designed to achieve optimum growth conditions with respect to electron donors, salinity, temperature, and pH. Under these optimized conditions, experimental fractionation factors ranged from 2.......0 to 42.0 per thousand. Salinity, incubation temperature, pH, and phylogeny had no systematic effect on the sulfur isotope fractionation. There was no correlation between isotope fractionation and sulfate reduction rate. The type of dissimilatory bisulfite reductase also had no effect on fractionation...

  18. PHYLOGENETIC ANALYSIS AND AUTECOLOGY OF SPORE-FORMING BACTERIA FROM HYPERSALINE ENVIRONMENTS.

    Science.gov (United States)

    Gladka, G V; Romanovskaya, V A; Tashyreva, H O; Tashyrev, O B

    2015-01-01

    Multi-resistant to extreme factors spore-forming bacteria of Bacillus genus are isolated from hypersaline environments of the Crimea (Ukraine) and the Dead Sea (Israel). Phylogenetic analysis showed distinction of dominating extremophilic culturable species in studied regions. In Crimean environments they are B. mojavensis and B. simplex, in the Dead Sea ecosystem--B. subtilis subsp. spizizenii, B. subtilis subsp. subtilis, B. licheniformis and B. simplex. Isolates are simultaneously halotolerant and resistant to UV radiation. Strains isolated from the Dead Sea and the Crimea environments were resistant to UV: LD90 and LD99.99 made 100-170 J/m2 and 750-1500 J/m2 respectively. Spores showed higher UV-resistance (LD99.99-2500 J/m2) than the vegetative cells. However the number of spores made 0.02-0.007% of the whole cell population, and should not significantly affect the UV LD99.99 value. Isolates of both environments were halotolerant in the range of 0.1-10% NaCl and thermotolerant in the range of 20-50 °C, and didn't grow at 15 °C. Survival strategy of spore-forming bacteria from hypersaline environments under high UV radiation level can be performed by spore formation which minimize cell damage as well as efficient DNA-repair systems that remove damages.

  19. Thermophilic (55 - 65°C) and extreme thermophilic (70 - 80°C) sulfate reduction in methanol and formate-fed UASB reactors

    NARCIS (Netherlands)

    Vallero, M.V.G.; Camarero, E.; Lettinga, G.; Lens, P.N.L.

    2004-01-01

    The feasibility of thermophilic (55-65 degreesC) and extreme thermophilic (70-80 degreesC) sulfate-reducing processes was investigated in three lab-scale upflow anaerobic sludge bed (UASB) reactors fed with either methanol or formate as the sole substrates and inoculated with mesophilic granular

  20. Desulfothermobacter acidiphilus gen. nov., sp. nov., a thermoacidophilic sulfate-reducing bacterium isolated from a terrestrial hot spring.

    Science.gov (United States)

    Frolov, E N; Zayulina, K S; Kopitsyn, D S; Kublanov, I V; Bonch-Osmolovskaya, E A; Chernyh, N A

    2018-03-01

    An anaerobic sulfate-reducing micro-organism, strain 3408-1 T , was isolated from a terrestrial hot spring in Kamchatka peninsula (Russia). The cells were spore-forming rods with a Gram-positive type of cell wall. The new isolate was a moderately thermoacidophilic anaerobe able to grow either by sulfate or thiosulfate respiration with H2 or formate as substrates, or by fermenting yeast extract, maltose, sucrose, glucose and pyruvate. The fermentation products were acetate, CO2 and H2. The pH range for growth was 2.9-6.5, with an optimum at 4.5. The temperature range for growth was 42-70 °C, with an optimum at 55 °C. The G+C content of DNA was 58 mol%. Phylogenetic analysis of the 16S rRNA gene showed that strain 3408-1 T belongs to the family Thermoanaerobacteraceae, order Thermoanaerobacterales and was distantly related to the species of the genus Ammonifex(93-94 % sequence similarity). On the basis of physiological properties and results of phylogenetic analysis, strain 3408-1 T is considered to represent a novel species of a new genus, for which the name Desulfothermobacter acidiphilus gen. nov., sp. nov. is proposed. The type strain is 3408-1 T (=DSM 105356 T =VKM B-3183 T ).

  1. A simple identification method for spore-forming bacteria showing high resistance against γ-rays

    International Nuclear Information System (INIS)

    Koshikawa, Tomihiko; Sone, Koji; Kobayashi, Toshikazu

    1993-01-01

    A simple identification method was developed for spore-forming bacteria which are highly resistant against γ-rays. Among 23 species of Bacillus studied, the spores of Bacillus megaterium, B. cereus, B. thuringiensis, B. pumilus and B. aneurinolyticus showed high resistance against γ-rays as compared with other spores of Bacillus species. Combination of the seven kinds of biochemical tests, namely, the citrate utilization test, nitrate reduction test, starch hydrolysis test, Voges-Proskauer reaction test, gelatine hydrolysis test, mannitol utilization test and xylose utilization test showed a characteristic pattern for each species of Bacillus. The combination pattern of each the above tests with a few supplementary test, if necessary, was useful to identify Bacillus species showing high radiation resistance against γ-rays. The method is specific for B. megaterium, B. thuringiensis and B. pumilus, and highly selective for B. aneurinolyticus and B. cereus. (author)

  2. Investigation of spore forming bacterial flooding for enhanced oil recovery in a North Sea chalk Reservoir

    DEFF Research Database (Denmark)

    Halim, Amalia Yunita; Nielsen, Sidsel Marie; Eliasson Lantz, Anna

    2015-01-01

    Little has been done to study microbial enhanced oil recovery (MEOR) in chalk reservoirs. The present study focuses on core flooding experiments designed to see microbial plugging and its effect on oil recovery. A pressure tapped core holder was used for this purpose. A spore forming bacteria...... Bacillus licheniformis 421 was used as it was shown to be a good candidate in a previous study. Bacterial spore can penetrate deeper into the chalk rock, squeezing through the pore throats. Our results showed that injection of B. licheniformis 421 as a tertiary oil recovery method, in the residual oil...... saturation state, was able to produce additionally 1.0-2.3% original oil in place (OOIP) in homogeneous cores and 6.9-8.8% OOIP in heterogeneous cores. In addition, the pressure gradient was much higher in the heterogeneous cores, which confirms that bacterial selective plugging plays an important role...

  3. Distinguishing iron-reducing from sulfate-reducing conditions

    Science.gov (United States)

    Chapelle, F.H.; Bradley, P.M.; Thomas, M.A.; McMahon, P.B.

    2009-01-01

    Ground water systems dominated by iron- or sulfate-reducing conditions may be distinguished by observing concentrations of dissolved iron (Fe2+) and sulfide (sum of H2S, HS-, and S= species and denoted here as "H2S"). This approach is based on the observation that concentrations of Fe2+ and H2S in ground water systems tend to be inversely related according to a hyperbolic function. That is, when Fe2+ concentrations are high, H2S concentrations tend to be low and vice versa. This relation partly reflects the rapid reaction kinetics of Fe2+ with H2S to produce relatively insoluble ferrous sulfides (FeS). This relation also reflects competition for organic substrates between the iron- and the sulfate-reducing microorganisms that catalyze the production of Fe2+ and H 2S. These solubility and microbial constraints operate in tandem, resulting in the observed hyperbolic relation between Fe2+ and H 2S concentrations. Concentrations of redox indicators, including dissolved hydrogen (H2) measured in a shallow aquifer in Hanahan, South Carolina, suggest that if the Fe2+/H2S mass ratio (units of mg/L) exceeded 10, the screened interval being tapped was consistently iron reducing (H2 ???0.2 to 0.8 nM). Conversely, if the Fe 2+/H2S ratio was less than 0.30, consistent sulfate-reducing (H2 ???1 to 5 nM) conditions were observed over time. Concomitantly high Fe2+ and H2S concentrations were associated with H2 concentrations that varied between 0.2 and 5.0 nM over time, suggesting mixing of water from adjacent iron- and sulfate-reducing zones or concomitant iron and sulfate reduction under nonelectron donor-limited conditions. These observations suggest that Fe2+/H2S mass ratios may provide useful information concerning the occurrence and distribution of iron and sulfate reduction in ground water systems. ?? 2009 National Ground Water Association.

  4. Nitrate and sulfate reducers-retrievable number of bacteria and their activities in Indian waters

    Digital Repository Service at National Institute of Oceanography (India)

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

    Culturable heterotrophic, nitrate reducing and sulfate reducing bacteria (HB, NRB and SRB) were enumerated from 25, 50, 100 and 200 m depths at 15 stations and their potential activities viz. Nitrate reducing (NRA) and Sulfate reducing (SRA) were...

  5. The structural bases of long-term anabiosis in non-spore-forming bacteria

    Science.gov (United States)

    Suzina, Natalia E.; Mulyukin, Andrey L.; Dmitriev, Vladimir V.; Nikolaev, Yury A.; Shorokhova, Anna P.; Bobkova, Yulia S.; Barinova, Ekaterina S.; Plakunov, Vladimir K.; El-Registan, Galina I.; Duda, Vitalii I.

    2006-01-01

    Peculiarities of the structural organization in non-spore-forming bacteria associated with long-term anabiosis were revealed both in laboratory cultures and in natural populations isolated from 1 3-Myr-old Eastern Siberian permafrost and tundra soil. Different advanced methods were used, including (a) high-resolution electron microscopy; (b) simulation of in situ conditions in the laboratory by varying the composition of growth medium and cultivation conditions; (c) low-temperature fractionation to isolate and concentrate microbial cells from natural soils; (d) comparative morphological analysis of microbial cells in model cultures and natural soils (in situ). Under laboratory conditions, the intense formation of resting cells by representatives of various taxa of eubacteria and halophilic archaea occurred in 2 9-month-old cultures grown in carbon-, nitrogen-, or phosphorus-limited media, in starved cell suspensions in the presence of sodium silicate, or on soil agar. Among resting cells, we revealed cystlike forms having a complicated structure and common features. These included a thick capsule; a thickened and multiprofile cell wall; the presence of large intramembrane particles on PF- and EF-fracture surfaces; fine-grained or lumpy cytoplasm; and a condensed nucleoid. The general morphological properties, ultrastructural organization, physiological features of cystlike cells, and their ability to germinate under the appropriate conditions suggest the existence of constitutive dormancy in non-spore-forming bacteria. It was found that the majority of microorganisms in permafrost and tundra soil are cystlike cells, very similar to those in laboratory cultures. Anabiotic (resting) cystlike cells are responsible for the survival of non-spore-formers in extreme Earth habitats and may be regarded as possible analogs of extraterrestrial forms of microbial life.

  6. Thermophilic bacteria in Moroccan hot springs, salt marshes and desert soils

    OpenAIRE

    Aanniz,Tarik; Ouadghiri,Mouna; Melloul,Marouane; Swings,Jean; Elfahime,Elmostafa; Ibijbijen,Jamal; Ismaili,Mohamed; Amar,Mohamed

    2015-01-01

    The diversity of thermophilic bacteria was investigated in four hot springs, three salt marshes and 12 desert sites in Morocco. Two hundred and forty (240) thermophilic bacteria were recovered, identified and characterized. All isolates were Gram positive, rod-shaped, spore forming and halotolerant. Based on BOXA1R-PCR and 16S rRNA gene sequencing, the recovered isolates were dominated by the genus Bacillus (97.5%) represented by B. licheniformis (119), B. aerius (44), B. sonorensis (33), B. ...

  7. Gelria glutamica gen. nov., sp. a thermophilic oligately syntrophic glutamate-degrading anaerobe

    NARCIS (Netherlands)

    Plugge, C.M.; Balk, M.; Zoetendal, E.G.; Stams, A.J.M.

    2002-01-01

    A novel anaerobic, Gram-positive, thermophilic, spore-forming, obligately syntrophic, glutamate-degrading bacterium, strain TGO(T), was isolated from a propionate-oxidizing methanogenic enrichment culture. The axenic culture was obtained by growing the bacterium on pyruvate. Cells were rod-shaped

  8. Isolation and characterization of Caldicellulosiruptor lactoaceticus sp. nov., an extremely thermophilic, cellulolytic, anaerobic bacterium

    DEFF Research Database (Denmark)

    Mladenovska, Zuzana; Mathrani, Indra M.; Ahring, Birgitte Kiær

    1995-01-01

    An anaerobic, extremely thermophilic, cellulolytic, non-spore-forming bacterium, strain 6A, was isolated from an alkaline hot spring in Hverageroi, Iceland. The bacterium was non-motile, rod-shaped (1.5-3.5 x 0.7 mu m) and occurred singly, in pairs or in chains and stained gram-negative. The growth...

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

    NARCIS (Netherlands)

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

    2003-01-01

    This paper describes a novel bioscrubber concept for biological flue gas desulfurization, based on the recycling of a cell suspension of sulfite/sulfate reducing bacteria between a scrubber and a sulfite/sulfate reducing hydrogen fed bioreactor. Hydrogen metabolism in sulfite/sulfate reducing cell

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

    OpenAIRE

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

    2016-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Wall, Judy D. [Univ. of Missouri, Columbia, MO (United States)

    2015-02-16

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

  12. Toxigenic potential and heat survival of spore-forming bacteria isolated from bread and ingredients.

    Science.gov (United States)

    De Bellis, Palmira; Minervini, Fiorenza; Di Biase, Mariaelena; Valerio, Francesca; Lavermicocca, Paola; Sisto, Angelo

    2015-03-16

    Fifty-four spore-forming bacterial strains isolated from bread ingredients and bread, mainly belonging to the genus Bacillus (including Bacillus cereus), together with 11 reference strains were investigated to evaluate their cytotoxic potential and heat survival in order to ascertain if they could represent a risk for consumer health. Therefore, we performed a screening test of cytotoxic activity on HT-29 cells using bacterial culture filtrates after growing bacterial cells in Brain Heart Infusion medium and in the bread-based medium Bread Extract Broth (BEB). Moreover, immunoassays and PCR analyses, specifically targeting already known toxins and related genes of B. cereus, as well as a heat spore inactivation assay were carried out. Despite of strain variability, the results clearly demonstrated a high cytotoxic activity of B. cereus strains, even if for most of them it was significantly lower in BEB medium. Cytotoxic activity was also detected in 30% of strains belonging to species different from B. cereus, although, with a few exceptions (e.g. Bacillus simplex N58.2), it was low or very low. PCR analyses detected the presence of genes involved in the production of NHE, HBL or CytK toxins in B. cereus strains, while genes responsible for cereulide production were not detected. Production of NHE and HBL toxins was also confirmed by specific immunoassays only for B. cereus strains even if PCR analyses revealed the presence of related toxin genes also in some strains of other species. Viable spore count was ascertained after a heat treatment simulating the bread cooking process. Results indicated that B. amyloliquefaciens strains almost completely survived the heat treatment showing less than 2 log-cycle reductions similarly to two strains of B. cereus group III and single strains belonging to Bacillus subtilis, Bacillus mojavensis and Paenibacillus spp. Importantly, spores from strains of the B. cereus group IV exhibited a thermal resistance markedly lower than B

  13. Enhanced sulfate reduction with acidogenic sulfate-reducing bacteria

    International Nuclear Information System (INIS)

    Wang Aijie; Ren Nanqi; Wang Xu; Lee Duujong

    2008-01-01

    Sulfate reduction in a continuous flow, acidogenic reactor using molasses wastewater as the carbon source was studied at varying chemical oxygen demand/sulfate (COD/SO 4 2- ) ratios. At a critical COD/SO 4 2- ratio of 2.7, neither COD nor sulfate were in excess for extra production of ethanol or acetate in the reactor. An acetic-type microbial metabolism was established with sulfate-reducing bacteria (SRB) significantly consuming hydrogen and volatile fatty acids produced by acidogenic bacteria and hydrogen producing acetogens in degrading COD, thereby yielding sulfate removal rate >94.6%. A low critical COD/SO 4 2- ratio of 1.6 was also observed with the enriched ASRB population in reactor which overcomes the barrier to the treatment capability of sulfate-laden wastewater treatment with limited COD supply

  14. Effect of bactericides on sulfate-reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsova, T A; Gareyshina, A Z; Limanov, V Ye; Neizvestnoya, R G; Yalymova, A G

    1980-01-01

    A study was made of the effect on sulfate-reducing bacteria (SRD) of different bactericides under laboratory conditions. The tests were conducted according to the technique developed in the VNIISPTneft'. A total of 36 chemical reagents were checked. The majority of them completely suppressed the growth of the accumulating culture of the SRD with different concentration of bactericide. The reagents which have good bactericidal action were verified for anticorrosion properties and were tested on field water from well 520 and 6334 of the Aznakayevskiy UKPN. The study results indicated that in selecting the dosing of bactericides on the accumulation culture of the SRD, the bactericidal effect is observed with lower concentration than the SRD collected from the near-face well zones.

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

    Science.gov (United States)

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

    2010-05-01

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

  16. Differentiation between spore-forming and asporogenic bacteria using a PCR and southern hybridization based method

    Energy Technology Data Exchange (ETDEWEB)

    Brill, J.A.; Wiegel, J. [Univ. of Georgia, Athens, GA (United States)

    1997-12-31

    A set of molecular probes was devised to develop a method for screening for the presence of sequences homologous to three representative genes exclusively involved in endosporulation. Based on known gene sequences, degenerate PCR primers were designed against spo0A and ssp. Experimental conditions were devised under which homologs of both genes were consistently detected in endospore-forming bacteria, but not in asporogenic bacteria. The PCR amplification products and dpaA/B from Bacillus subtilis were used as hybridization probes for Southern blots. Identical conditions were used with the genomic DNA from endospore-forming and asporogenic bacteria. We therefore concluded that the probes specifically detect the targeted sporulation genes and we obtained no indication that genes homologous to ssp, spo0A and dpaA/B are present in asporogenic bacteria. Thus, this assay can potentially be used to detect spore-forming bacteria in various kinds of samples and to distinguish between bacteria containing sporulation genes and those who do not regardless of whether sporulation is observed or not. 43 refs., 3 figs., 1 tab.

  17. The prevalence and control of Bacillus and related spore-forming bacteria in the dairy industry

    Directory of Open Access Journals (Sweden)

    Nidhi eGopal

    2015-12-01

    Full Text Available Milk produced in udder cells is sterile but due to its high nutrient content, it can be a good growth substrate for contaminating bacteria. The quality of milk is monitored via somatic cell counts and total bacterial counts, with prescribed regulatory limits to ensure quality and safety. Bacterial contaminants can cause disease, or spoilage of milk and its secondary products. Aerobic spore-forming bacteria, such as those from the genera Sporosarcina, Paenisporosarcina, Brevibacillus, Paenibacillus, Geobacillus and Bacillus, are a particular concern in this regard as they are able to survive industrial pasteurisation and form biofilms within pipes and stainless steel equipment. These single or multiple-species biofilms become a reservoir of spoilage microorganisms and a cycle of contamination can be initiated. Indeed, previous studies have highlighted that these microorganisms are highly prevalent in dead ends, corners, cracks, crevices, gaskets, valves and the joints of stainless steel equipment used in the dairy manufacturing plants. Hence, adequate monitoring and control measures are essential to prevent spoilage and ensure consumer safety. Common controlling approaches include specific cleaning-in-place processes, chemical and biological biocides and other novel methods. In this review, we highlight the problems caused by these microorganisms, and discuss issues relating to their prevalence, monitoring thereof and control with respect to the dairy industry.

  18. Lipoquinones of some spore-forming rods, lactic-acid bacteria and actinomycetes.

    Science.gov (United States)

    Hess, A; Holländer, R; Mannheim, W

    1979-11-01

    The respiratory quinones of 73 strains of Gram-positive bacteria including spore-forming rods, lactic-acid bacteria and actinomyctes were examined. Menaquinones with seven isoprenoid units (MK-7) were the main quinone type found in representatives of the genus Bacillus and in Sporolactobacillus inulinus. However, a strain of B. thuringiensis produced MK-8 in addition to MK-7, and strains of B. lentus and B. pantothenticus appeared to produce MK-9 and MK-8, respectively, with no MK-7. In the clostridia and lactic-acid bacteria, no quinones were found, except in Pediococcus cerevisiae NCTC 8066 and Lactobacillus casei subsp. rhamnosus ATCC 7469, which contained menaquinones, and Streptococcus faecalis NCTC 775 and HIM 478-1, which contained demethylmenaquinones, in relatively low concentrations. Menaquinones were also found in the actinomycetes (except Actinomyces odontolyticus and Bifidobacterium bifidum which did not produce any quinones) and in Protaminobacter alboflavus ATCC 8458, the so-called Actinobacillus actinoides ATCC 15900 and Noguchia granulosis NCTC 10559.

  19. Management practices and forage quality affecting the contamination of milk with anaerobic spore-forming bacteria.

    Science.gov (United States)

    Zucali, Maddalena; Bava, Luciana; Colombini, Stefania; Brasca, Milena; Decimo, Marilù; Morandi, Stefano; Tamburini, Alberto; Crovetto, G Matteo

    2015-04-01

    Anaerobic spore-forming bacteria (ASFB) in milk derive from the farm environment, and the use of silages and management practices are the main responsible of milk ASFB contamination. The aim of this study was to evaluate the relationships between feeding, milking routine and cow hygiene and milk and Grana Padano cheese (produced with and without lysozyme) ASFB contamination. The study involved 23 dairy farms. ASFB in corn silage were on average 2.34 ± 0.87 log10 MPN g(-1). For grass, Italian ryegrass and alfalfa, ASFB (log10 MPN g(-1)) were numerically higher for silages (3.22) than hays (2.85). The use of corn silages of high quality (high lactic and acetic acids concentrations) decreased the milk ASFB contamination, whilst the use of herbage silages did not affect it. The presence (>40%) of cows with dirty udders increased the ASFB contamination of milk, while forestripping had a positive effect (-9% ASFB). Ripened Grana Padano had an ASFB count below the analytical limit; Clostridium tyrobutyricum DNA was found only in wheels produced without lysozyme, which also showed late blowing. The factors increasing milk spore contamination were corn silage quality, cow udder hygiene and inadequate milking routine. Late blowing was present only in cheeses without lysozyme. © 2014 Society of Chemical Industry.

  20. New thermophilic anaerobes that decompose crystalline cellulose

    Energy Technology Data Exchange (ETDEWEB)

    Taya, M; Hinoki, H; Suzuki, Y; Yagi, T; Yap, M G.S.; Kobayashi, T

    1985-01-01

    Two strains (designated as 25A and 3B) of cellulolytic, thermophilic, anaerobic, spore-forming bacteria were newly isolated from an alkaline hot spring through enrichment cultures at 60/sup 0/C. Though strain 25A was nearly identical to Clostridium thermocellum ATCC 27405 as a reference strain, strain 3B had some characteristics different from the reference; no flagellation, alkalophilic growth property (optimum pH of 7.5-8) and orange-colored pigmentation of the cell mass. Strain 3B effectively decomposed micro-crystalline cellulose (Avicel) and raw cellulosics (rice straw, newspaper, and bagasse) without physical or chemical pretreatments. 20 references, 2 figures, 2 tables.

  1. Long-term cryopreservation of non-spore-forming fungi in Microbank™ beads for plant pathological investigations.

    Science.gov (United States)

    Lakshman, Dilip K; Singh, Vimla; Camacho, Manuel E

    2018-05-01

    Long-term preservation of experimental fungi without genetic, morphological, and pathogenic changes is of paramount importance in mycological and plant pathological investigations. Several cryogenic and non-cryogenic methods are available for the preservation of fungi, but the methods can be cumbersome, hazardous, expensive, and often not suitable for long-term storage of non-spore-forming (sterile) fungi. A method of preservation of spore-forming fungi in commercially available porous beads (Micrbank™) under cryogenic condition was successfully tested for three non-spore-forming basidiomycetes genera: Rhizoctonia solani (teleomorph: Thanatephorus cucumeris) (n = 19), Ceratobasidium species (n = 1), and Waitea circinata (n = 3), and a non-spore forming ascomycetes, Sclerotinia sclerotiorum (n = 1). For comparison, spore-forming ascomycetous fungi, Alternaria alternata (n = 1), Bauveria basiana (n = 2), Botrytis cinerea (n = 1), Fusarium oxysporum f.sp. gladiolii (n = 1), Trichoderma spp. (n = 3), and Thielaviopsis basicola (n = 2) were also cryopreserved in Microbank beads. Viable fungal isolates of all test species were retrieved after five years of storage at -80 °C, which was longer than the viabilities of the corresponding isolates cryopreserved in agar plugs or colonized wheat seeds. Fungi revived from the Microbank beads maintained identical morphology and cultural characteristics of the parent isolates. Randomly selected Rhizoctonia isolates revived from the Microbank beads maintained respective pathological properties of the parent isolates; also, no mutation was detected in the internal transcribed spacer (ITS) ribosomal DNA when compared with respective cultures maintained at ambient temperature. This finding demonstrated the utility of cryopreservation in Microbank beads as a convenient alternative to conventional long-term preservation of a wide group of fungal cultures for plant pathological investigations

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

    Science.gov (United States)

    Barton, Larry L; Fauque, Guy D

    2009-01-01

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

  3. Linking Microbial Ecology to Geochemistry in Sulfate Reducing Systems

    Science.gov (United States)

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

    2013-12-01

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

  4. Isolation of thermophilic Desulfotomaculum strains with methanol and sulfite from solfataric mud pools, and characterization of Desulfotomaculum solfataficum sp nov

    NARCIS (Netherlands)

    Goorissen, H.P.; Boschker, H.T.S.; Stams, A.J.M.; Hansen, T.A.

    2003-01-01

    Four strains of thermophilic, endospore-forming, sulfate-reducing bacteria were enriched and isolated from hot solfataric fields in the Krafla area of north-east Iceland, using methanol and sulfite as substrates. Morphologically, these strains resembled thermophilic Desulfotomaculum species. The

  5. Isolation of thermophilic Desulfotomaculum strains with methanol and sulfite from solfataric mud pools, and characterization of Desulfotomaculum solfataficum sp nov

    NARCIS (Netherlands)

    Goorissen, HP; Boschker, HTS; Stams, AJM; Hansen, TA

    Four strains of thermophilic, endospore-forming, sulfate-reducing bacteria were enriched and isolated from hot solfataric fields in the Krafla area of north-east Iceland, using methanol and sulfite as substrates. Morphologically, these strains resembled thermophilic Desulfotomaculum species. The

  6. Isolation of thermophilic Desulfotomaculum strains with methanol and sulphite from solfataric mud pools, and characterization of Desulfotomaculum solfataricum

    NARCIS (Netherlands)

    Goorissen, H.P.; Stams, A.J.M.; Hansen, T.A.

    2003-01-01

    Four strains of thermophilic, endospore-forming, sulfate-reducing bacteria were enriched and isolated from hot solfataric fields in the Krafla area of north-east Iceland, using methanol and sulfite as substrates. Morphologically, these strains resembled thermophilic Desulfotomaculum species. The

  7. Characterization of sulfate reducing bacteria isolated from urban soil

    Science.gov (United States)

    Zhang, Mingliang; Wang, Haixia

    2017-05-01

    Sulfate reducing bacteria (SRB) was isolated from urban soil and applied for the remediation of heavy metals pollution from acid mine drainage. The morphology and physiological characteristics (e.g. pH and heavy metals tolerance) of SRB was investigated. The SRB was gram-negative bacteria, long rod with slight curve, cell size 0.5× (1.5-2.0) μm. The pH of medium had significant effect on SRB growth and the efficiency of sulfate reduction, and it showed that the suitable pH range was 5-9 and SRB could not survive at pH less than 4. The maximum tolerance of Fe (II), Zn (II), Cd (II), and Cu (II) under acidic condition (pH 5.0) was about 600 mg/L, 150 mg/L, 25 mg/L and 25 mg/L, respectively. The result indicated that SRB isolated in this study could be used for the bioremediation of acid mine drainage (pH>4) within the heavy metals concentrations tolerance.

  8. Microbial fuel cell based on electroactive sulfate-reducing biofilm

    International Nuclear Information System (INIS)

    Angelov, Anatoliy; Bratkova, Svetlana; Loukanov, Alexandre

    2013-01-01

    Highlights: ► Regulation and management of electricity generation by variation of residence time. ► Design of microbial fuel cell based on electroactive biofilm on zeolite. ► Engineering solution for removing of the obtained elemental sulfur. - abstract: A two chambered laboratory scale microbial fuel cell (MFC) has been developed, based on natural sulfate-reducing bacterium consortium in electroactive biofilm on zeolite. The MFC utilizes potassium ferricyanide in the cathode chamber as an electron acceptor that derives electrons from the obtained in anode chamber H 2 S. The molecular oxygen is finally used as a terminal electron acceptor at cathode compartment. The generated power density was 0.68 W m −2 with current density of 3.2 A m −2 at 150 Ω electrode resistivity. The hydrogen sulfide itself is produced by microbial dissimilative sulfate reduction process by utilizing various organic substrates. Finally, elemental sulfur was identified as the predominant final oxidation product in the anode chamber. It was removed from MFC through medium circulation and gathering in an external tank. This report reveals dependence relationship between the progress of general electrochemical parameters and bacterial sulfate-reduction rate. The presented MFC design can be used for simultaneous sulfate purification of mining drainage wastewater and generation of renewable electricity

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

    NARCIS (Netherlands)

    Ozuolmez, D.; Na, H.; Lever, M.A.; Kjeldsen, K.U.; Jørgensen, B.B.; Plugge, C.M.

    2015-01-01

    Acetate is a major product of fermentation processes and an important substrate for sulfate reducing bacteria and methanogenic archaea. Most studies on acetate catabolism by sulfate reducers and methanogens have used pure cultures. Less is known about acetate conversion by mixed pure cultures and

  10. Tracking spore-forming bacteria in food: from natural biodiversity to selection by processes.

    Science.gov (United States)

    Postollec, Florence; Mathot, Anne-Gabrielle; Bernard, Muriel; Divanac'h, Marie-Laure; Pavan, Sonia; Sohier, Danièle

    2012-08-01

    Sporeforming bacteria are ubiquitous in the environment and exhibit a wide range of diversity leading to their natural prevalence in foodstuff. The state of the art of sporeformer prevalence in ingredients and food was investigated using a multiparametric PCR-based tool that enables simultaneous detection and identification of various genera and species mostly encountered in food, i.e., Alicyclobacillus, Anoxybacillus flavithermus, Bacillus, B. cereus group, B. licheniformis, B. pumilus, B. sporothermodurans, B. subtilis, Brevibacillus laterosporus, Clostridium, Geobacillus stearothermophilus, Moorella and Paenibacillus species. In addition, 16S rDNA sequencing was used to extend identification to other possibly present contaminants. A total of 90 food products, with or without visible trace of spoilage were analysed, i.e., 30 egg-based products, 30 milk and dairy products and 30 canned food and ingredients. Results indicated that most samples contained one or several of the targeted genera and species. For all three tested food categories, 30 to 40% of products were contaminated with both Bacillus and Clostridium. The percentage of contaminations associated with Clostridium or Bacillus represented 100% in raw materials, 72% in dehydrated ingredients and 80% in processed foods. In the last two product types, additional thermophilic contaminants were identified (A. flavithermus, Geobacillus spp., Thermoanaerobacterium spp. and Moorella spp.). These results suggest that selection, and therefore the observed (re)-emergence of unexpected sporeforming contaminants in food might be favoured by the use of given food ingredients and food processing technologies. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Handling technique of spore-forming bacteria in radiation sterilization. 2. Determination of numbers and radiation resistance of spores

    International Nuclear Information System (INIS)

    Koshikawa, Tomihiko

    1994-01-01

    Stepwise ten-fold dilution of bacterial solution is required in the determination of bacterial spores. For this, the selection of diluted solution is important according to the purpose of experiment. First, the preparation of suspension of bacterial spores and selection of diluted solution are presented. Then, a method for determining the number of bacterial spores in materials is outlined in terms of dilution methods of bacterial solution (shaking and homogenization) and application method of diluted solution to the plating medium. Finally, a method for determining radiation resistance of spore-forming bacteria is explained according to the measurement conditions (suspension of bacterial spores and filters applied with bacterial spores). (N.K.)

  12. Handling technique of spore-forming bacteria in radiation sterilization. 2. Determination of numbers and radiation resistance of spores

    Energy Technology Data Exchange (ETDEWEB)

    Koshikawa, Tomihiko [Japan Radioisotope Association, Shiga (Japan). Koka Laboratory

    1994-12-01

    Stepwise ten-fold dilution of bacterial solution is required in the determination of bacterial spores. For this, the selection of diluted solution is important according to the purpose of experiment. First, the preparation of suspension of bacterial spores and selection of diluted solution are presented. Then, a method for determining the number of bacterial spores in materials is outlined in terms of dilution methods of bacterial solution (shaking and homogenization) and application method of diluted solution to the plating medium. Finally, a method for determining radiation resistance of spore-forming bacteria is explained according to the measurement conditions (suspension of bacterial spores and filters applied with bacterial spores). (N.K.).

  13. Community size and metabolic rates of psychrophilic sulfate-reducing bacteria in Arctic marine sediments

    DEFF Research Database (Denmark)

    Knoblauch, C.; Jørgensen, BB; Harder, J.

    1999-01-01

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

  14. Effect of hydraulic retention time on metal precipitation in sulfate reducing inverse fluidized bed reactors

    KAUST Repository

    Villa-Gó mez, Denys Kristalia; Enright, Anne Marie; Rini, Eki Listya; Buttice, Audrey L.; Kramer, Herman J M; Lens, Piet Nl L

    2014-01-01

    BACKGROUND: Metal sulfide recovery in sulfate reducing bioreactors is a challenge due to the formation of small precipitates with poor settling properties. The size of the metal sulfide precipitates with the change in operational parameters

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-04-01

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

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

    Science.gov (United States)

    Hamilton-Brehm, Scott D; Gibson, Robert A; Green, Stefan J; Hopmans, Ellen C; Schouten, Stefan; van der Meer, Marcel T J; Shields, John P; Damsté, Jaap S S; Elkins, James G

    2013-03-01

    A novel sulfate-reducing bacterium designated OPF15(T) was isolated from Obsidian Pool, Yellowstone National Park, Wyoming. The phylogeny of 16S rRNA and functional genes (dsrAB) placed the organism within the family Thermodesulfobacteriaceae. The organism displayed hyperthermophilic temperature requirements for growth with a range of 70-90 °C and an optimum of 83 °C. Optimal pH was around 6.5-7.0 and the organism required the presence of H2 or formate as an electron donor and CO2 as a carbon source. Electron acceptors supporting growth included sulfate, thiosulfate, and elemental sulfur. Lactate, acetate, pyruvate, benzoate, oleic acid, and ethanol did not serve as electron donors. Membrane lipid analysis revealed diacyl glycerols and acyl/ether glycerols which ranged from C14:0 to C20:0. Alkyl chains present in acyl/ether and diether glycerol lipids ranged from C16:0 to C18:0. Straight, iso- and anteiso-configurations were found for all lipid types. The presence of OPF15(T) was also shown to increase cellulose consumption during co-cultivation with Caldicellulosiruptor obsidiansis, a fermentative, cellulolytic extreme thermophile isolated from the same environment. On the basis of phylogenetic, phenotypic, and structural analyses, Thermodesulfobacterium geofontis sp. nov. is proposed as a new species with OPF15(T) representing the type strain.

  17. Thioarsenate Formation Coupled with Anaerobic Arsenite Oxidation by a Sulfate-Reducing Bacterium Isolated from a Hot Spring

    Directory of Open Access Journals (Sweden)

    Geng Wu

    2017-07-01

    Full Text Available Thioarsenates are common arsenic species in sulfidic geothermal waters, yet little is known about their biogeochemical traits. In the present study, a novel sulfate-reducing bacterial strain Desulfotomaculum TC-1 was isolated from a sulfidic hot spring in Tengchong geothermal area, Yunnan Province, China. The arxA gene, encoding anaerobic arsenite oxidase, was successfully amplified from the genome of strain TC-1, indicating it has a potential ability to oxidize arsenite under anaerobic condition. In anaerobic arsenite oxidation experiments inoculated with strain TC-1, a small amount of arsenate was detected in the beginning but became undetectable over longer time. Thioarsenates (AsO4-xSx2- with x = 1–4 formed with mono-, di- and tri-thioarsenates being dominant forms. Tetrathioarsenate was only detectable at the end of the experiment. These results suggest that thermophilic microbes might be involved in the formation of thioarsenates and provide a possible explanation for the widespread distribution of thioarsenates in terrestrial geothermal environments.

  18. Thioarsenate Formation Coupled with Anaerobic Arsenite Oxidation by a Sulfate-Reducing Bacterium Isolated from a Hot Spring.

    Science.gov (United States)

    Wu, Geng; Huang, Liuqin; Jiang, Hongchen; Peng, Yue'e; Guo, Wei; Chen, Ziyu; She, Weiyu; Guo, Qinghai; Dong, Hailiang

    2017-01-01

    Thioarsenates are common arsenic species in sulfidic geothermal waters, yet little is known about their biogeochemical traits. In the present study, a novel sulfate-reducing bacterial strain Desulfotomaculum TC-1 was isolated from a sulfidic hot spring in Tengchong geothermal area, Yunnan Province, China. The arxA gene, encoding anaerobic arsenite oxidase, was successfully amplified from the genome of strain TC-1, indicating it has a potential ability to oxidize arsenite under anaerobic condition. In anaerobic arsenite oxidation experiments inoculated with strain TC-1, a small amount of arsenate was detected in the beginning but became undetectable over longer time. Thioarsenates (AsO 4-x S x 2- with x = 1-4) formed with mono-, di- and tri-thioarsenates being dominant forms. Tetrathioarsenate was only detectable at the end of the experiment. These results suggest that thermophilic microbes might be involved in the formation of thioarsenates and provide a possible explanation for the widespread distribution of thioarsenates in terrestrial geothermal environments.

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

    Science.gov (United States)

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

    2015-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Derya eOzuolmez

    2015-05-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Boopathy, R. [Argonne National Lab., IL (United States); Kulpa, C.F. [Notre Dame Univ., IN (United States). Dept. of Biological Sciences

    1994-06-01

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

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

    International Nuclear Information System (INIS)

    Boopathy, R.; Kulpa, C.F.

    1994-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Juliana Pacheco da Rosa

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

  4. Sulfate-reducing bacteria in rice field soil and on rice roots.

    Science.gov (United States)

    Wind, T; Stubner, S; Conrad, R

    1999-05-01

    Rice plants that were grown in flooded rice soil microcosms were examined for their ability to exhibit sulfate reducing activity. Washed excised rice roots showed sulfate reduction potential when incubated in anaerobic medium indicating the presence of sulfate-reducing bacteria. Rice plants, that were incubated in a double-chamber (phylloshpere and rhizosphere separated), showed potential sulfate reduction rates in the anoxic rhizosphere compartment. These rates decreased when oxygen was allowed to penetrate through the aerenchyma system of the plants into the anoxic root compartment, indicating that sulfate reducers on the roots were partially inhibited by oxygen or that sulfate was regenerated by oxidation of reduced S-compounds. The potential activity of sulfate reducers on rice roots was consistent with MPN enumerations showing that H2-utilizing sulfate-reducing bacteria were present in high numbers on the rhizoplane (4.1 x 10(7) g-1 root fresh weight) and in the adjacent rhizosperic soil (2.5 x 10(7) g-1 soil dry weight). Acetate-oxidizing sulfate reducers, on the other hand, showed highest numbers in the unplanted bulk soil (1.9 x 10(6) g-1 soil dry weight). Two sulfate reducing bacteria were isolated from the highest dilutions of the MPN series and were characterized physiologically and phylogenetically. Strain F1-7b which was isolated from the rhizoplane with H2 as electron donor was related to subgroup II of the family Desulfovibrionaceae. Strain EZ-2C2, isolated from the rhizoplane on acetate, grouped together with Desulforhabdus sp. and Syntrophobacter wolinii. Other strains of sulfate-reducing bacteria originated from bulk soil of rice soil microcosms and were isolated using different electron donors. From these isolates, strains R-AcA1, R-IbutA1, R-PimA1 and R-AcetonA170 were Gram-positive bacteria which were affiliated with the genus Desulfotomaculum. The other isolates were members of subgroup II of the Desulfovibrionaceae (R-SucA1 and R-LacA1), were

  5. Effect of hydraulic retention time on metal precipitation in sulfate reducing inverse fluidized bed reactors

    KAUST Repository

    Villa-Gómez, Denys Kristalia

    2014-02-13

    BACKGROUND: Metal sulfide recovery in sulfate reducing bioreactors is a challenge due to the formation of small precipitates with poor settling properties. The size of the metal sulfide precipitates with the change in operational parameters such as pH, sulfide concentration and reactor configuration has been previously studied. The effect of the hydraulic retention time (HRT) on the metal precipitate characteristics such as particle size for settling has not yet been addressed. RESULTS: The change in size of the metal (Cu, Zn, Pb and Cd) sulfide precipitates as a function of the HRT was studied in two sulfate reducing inversed fluidized bed (IFB) reactors operating at different chemical oxygen demand concentrations to produce high and low sulfide concentrations. The decrease of the HRT from 24 to 9h in both IFB reactors affected the contact time of the precipitates formed, thus making differences in aggregation and particle growth regardless of the differences in sulfide concentration. Further HRT decrease to 4.5h affected the sulfate reducing activity for sulfide production and hence, the supersaturation level and solid phase speciation. Metal sulfide precipitates affected the sulfate reducing activity and community in the biofilm, probably because of the stronger local supersaturation causing metal sulfides accumulation in the biofilm. CONCLUSIONS: This study shows that the HRT is an important factor determining the size and thus the settling rate of the metal sulfides formed in bioreactors.

  6. One-carbon metabolism in acetogenic and sulfate-reducing bacteria

    NARCIS (Netherlands)

    Visser, M.

    2015-01-01

    ABSTRACT

    One-carbon metabolism in acetogenic and sulfate-reducing bacteria

    Life on earth is sustained by the constant cycling of six essential elements: oxygen, hydrogen, nitrogen,

  7. Mechanisms and Effectivity of Sulfate Reducing Bioreactors Using a Chitinous Substrate in Treating Mining Influenced Water

    Science.gov (United States)

    Mining-influenced water (MIW) is the main environmental challenge associated with the mining industry. Passive MIW remediation can be achieved through microbial activity in sulfate-reducing bioreactors (SRBRs), but their actual removal rates depend on different factors, one of wh...

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

    Science.gov (United States)

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

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

    NARCIS (Netherlands)

    Lenz, M.; Hullebusch, van E.D.; Hommes, G.; Corvini, P.F.X.; Lens, P.N.L.

    2008-01-01

    This paper evaluates the use of upflow anaerobic sludge bed (UASB) bioreactors (30 degrees C, pH = 7.0) to remove selenium oxyanions from contaminated waters (790 mu g Se L-1) under methanogenic and sulfate-reducing conditions using lactate as electron donor. One UASB reactor received sulfate at

  10. Sulfide response analysis for sulfide control using a pS electrode in sulfate reducing bioreactors

    NARCIS (Netherlands)

    Villa Gomez, D.K.; Cassidy, J.; Keesman, K.J.; Sampaio, R.M.; Lens, P.N.L.

    2014-01-01

    Step changes in the organic loading rate (OLR) through variations in the influent chemical oxygen demand (CODin) concentration or in the hydraulic retention time (HRT) at constant COD/SO4 2- ratio (0.67) were applied to create sulfide responses for the design of a sulfide control in sulfate reducing

  11. Response And Recovery Of Sulfate-Reducing Biochemical Reactors From Aerobic Stress Events

    Science.gov (United States)

    Microbially-mediated treatment of mining-influenced water (MIW) through the implementation of sulfate-reducing biochemical reactors (BCRs) is an attractive option for passive, in situ remediation with low operating costs and reduced maintenance requirements. However, BCRs can be...

  12. Response And Recovery Of Sulfate-Reducing Biochemical Reactors From Aerobic Stress Events (Presentation)

    Science.gov (United States)

    Microbially-mediated treatment of mining-influenced water (MIW) through the implementation of sulfate-reducing biochemical reactors (BCR) is an attractive option for passive, in situ remediation with low operating costs and reduced maintenance requirements. However, BCRs can be ...

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

    Science.gov (United States)

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

    2012-10-01

    Sulfate-reducing permeable reactive zones (SR-PRZs) depend upon a complex microbial community to utilize a lignocellulosic substrate and produce sulfides, which remediate mine drainage by binding heavy metals. To gain insight into the impact of the microbial community composition on the startup time and pseudo-steady-state performance, functional genes corresponding to cellulose-degrading (CD), fermentative, sulfate-reducing, and methanogenic microorganisms were characterized in columns simulating SR-PRZs using quantitative polymerase chain reaction (qPCR) and denaturing gradient gel electrophoresis (DGGE). Duplicate columns were bioaugmented with sulfate-reducing or CD bacteria or biostimulated with ethanol or carboxymethyl cellulose and compared with baseline dairy manure inoculum and uninoculated controls. Sulfate removal began after ~ 15 days for all columns and pseudo-steady state was achieved by Day 30. Despite similar performance, DGGE profiles of 16S rRNA gene and functional genes at pseudo-steady state were distinct among the column treatments, suggesting the potential to control ultimate microbial community composition via bioaugmentation and biostimulation. qPCR revealed enrichment of functional genes in all columns between the initial and pseudo-steady-state time points. This is the first functional gene-based study of CD, fermentative and sulfate-reducing bacteria and methanogenic archaea in a lignocellulose-based environment and provides new qualitative and quantitative insight into startup of a complex microbial system. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

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

    NARCIS (Netherlands)

    Païssé, S.; Ghiglione, J.-F.; Marty, F.; Abbas, B.; Gueuné, H.; Sanchez Amaya, J.; Muyzer, G.; Quillet, L.

    2013-01-01

    In the present study, investigations were conducted on natural corrosion deposits to better understand the role of sulfate-reducing bacteria (SRB) in the accelerated corrosion process of carbon steel sheet piles in port environments. We describe the abundance and diversity of total and metabolically

  15. Syntrophic growth of sulfate-reducing bacteria and colorless sulfur bacteria during oxygen limitation

    NARCIS (Netherlands)

    vandenEnde, FP; Meier, J; vanGemerden, H

    Stable co-cultures of the sulfate-reducing bacterium Desulfovibrio desulfuricans PA2805 and the colorless sulfur bacterium Thiobacillus thioparus T5 were obtained in continuous cultures supplied with limiting amounts of lactate and oxygen while sulfate was present in excess. Neither species could

  16. Sulfate-reducing bacteria colonize pouches formed for ulcerative colitis but not for familial adenomatous polyposis.

    LENUS (Irish Health Repository)

    Duffy, M

    2012-02-03

    PURPOSE: Ileal pouch-anal anastomosis remains the "gold standard" in surgical treatment of ulcerative colitis and familial adenomatous polyposis. Pouchitis occurs mainly in patients with a background of ulcerative colitis, although the reasons for this are unknown. The aim of this study was to characterize differences in pouch bacterial populations between ulcerative colitis and familial adenomatous pouches. METHODS: After ethical approval was obtained, fresh stool samples were collected from patients with ulcerative colitis pouches (n = 10), familial adenomatous polyposis (n = 7) pouches, and ulcerative colitis ileostomies (n = 8). Quantitative measurements of aerobic and anaerobic bacteria were performed. RESULTS: Sulfate-reducing bacteria were isolated from 80 percent (n = 8) of ulcerative colitis pouches. Sulfate-reducing bacteria were absent from familial adenomatous polyposis pouches and also from ulcerative colitis ileostomy effluent. Pouch Lactobacilli, Bifidobacterium, Bacteroides sp, and Clostridium perfringens counts were increased relative to ileostomy counts in patients with ulcerative colitis. Total pouch enterococci and coliform counts were also increased relative to ileostomy levels. There were no significant quantitative or qualitative differences between pouch types when these bacteria were evaluated. CONCLUSIONS: Sulfate-reducing bacteria are exclusive to patients with a background of ulcerative colitis. Not all ulcerative colitis pouches harbor sulfate-reducing bacteria because two ulcerative colitis pouches in this study were free of the latter. They are not present in familial adenomatous polyposis pouches or in ileostomy effluent collected from patients with ulcerative colitis. Total bacterial counts increase in ulcerative colitis pouches after stoma closure. Levels of Lactobacilli, Bifidobacterium, Bacteroides sp, Clostridium perfringens, enterococci, and coliforms were similar in both pouch groups. Because sulfate-reducing bacteria are

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-07-15

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

  18. Anaerobic Thermophiles

    Directory of Open Access Journals (Sweden)

    Francesco Canganella

    2014-02-01

    Full Text Available The term “extremophile” was introduced to describe any organism capable of living and growing under extreme conditions. With the further development of studies on microbial ecology and taxonomy, a variety of “extreme” environments have been found and an increasing number of extremophiles are being described. Extremophiles have also been investigated as far as regarding the search for life on other planets and even evaluating the hypothesis that life on Earth originally came from space. The first extreme environments to be largely investigated were those characterized by elevated temperatures. The naturally “hot environments” on Earth range from solar heated surface soils and water with temperatures up to 65 °C, subterranean sites such as oil reserves and terrestrial geothermal with temperatures ranging from slightly above ambient to above 100 °C, to submarine hydrothermal systems with temperatures exceeding 300 °C. There are also human-made environments with elevated temperatures such as compost piles, slag heaps, industrial processes and water heaters. Thermophilic anaerobic microorganisms have been known for a long time, but scientists have often resisted the belief that some organisms do not only survive at high temperatures, but actually thrive under those hot conditions. They are perhaps one of the most interesting varieties of extremophilic organisms. These microorganisms can thrive at temperatures over 50 °C and, based on their optimal temperature, anaerobic thermophiles can be subdivided into three main groups: thermophiles with an optimal temperature between 50 °C and 64 °C and a maximum at 70 °C, extreme thermophiles with an optimal temperature between 65 °C and 80 °C, and finally hyperthermophiles with an optimal temperature above 80 °C and a maximum above 90 °C. The finding of novel extremely thermophilic and hyperthermophilic anaerobic bacteria in recent years, and the fact that a large fraction of them belong

  19. Efficiency of boiling and four other methods for genomic DNA extraction of deteriorating spore-forming bacteria from milk

    Directory of Open Access Journals (Sweden)

    Jose Carlos Ribeiro Junior

    2016-10-01

    Full Text Available The spore-forming microbiota is mainly responsible for the deterioration of pasteurized milk with long shelf life in the United States. The identification of these microorganisms, using molecular tools, is of particular importance for the maintenance of the quality of milk. However, these molecular techniques are not only costly but also labor-intensive and time-consuming. The aim of this study was to compare the efficiency of boiling in conjunction with four other methods for the genomic DNA extraction of sporulated bacteria with proteolytic and lipolytic potential isolated from raw milk in the states of Paraná and Maranhão, Brazil. Protocols based on cellular lysis by enzymatic digestion, phenolic extraction, microwave-heating, as well as the use of guanidine isothiocyanate were used. This study proposes a method involving simple boiling for the extraction of genomic DNA from these microorganisms. Variations in the quality and yield of the extracted DNA among these methods were observed. However, both the cell lysis protocol by enzymatic digestion (commercial kit and the simple boiling method proposed in this study yielded sufficient DNA for successfully carrying out the Polymerase Chain Reaction (PCR of the rpoB and 16S rRNA genes for all 11 strains of microorganisms tested. Other protocols failed to yield sufficient quantity and quality of DNA from all microorganisms tested, since only a few strains have showed positive results by PCR, thereby hindering the search for new microorganisms. Thus, the simple boiling method for DNA extraction from sporulated bacteria in spoiled milk showed the same efficacy as that of the commercial kit. Moreover, the method is inexpensive, easy to perform, and much less time-consuming.

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

    OpenAIRE

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

    2013-01-01

    Sulfate-reducing bacteria (SRB) colonize the guts of ∼50% of humans. We used genome-wide transposon mutagenesis and insertion-site sequencing, RNA-Seq, plus mass spectrometry to characterize genetic and environmental factors that impact the niche of Desulfovibrio piger, the most common SRB in a surveyed cohort of healthy US adults. Gnotobiotic mice were colonized with an assemblage of sequenced human gut bacterial species with or without D. piger and fed diets with different levels and types ...

  1. Hydrocarbon-degrading sulfate-reducing bacteria in marine hydrocarbon seep sediments

    OpenAIRE

    Kleindienst, Sara

    2012-01-01

    Microorganisms are key players in our biosphere because of their ability to degrade various organic compounds including a wide range of hydrocarbons. At marine hydrocarbon seeps, more than 90% of sulfate reduction (SR) is potentially coupled to non-methane hydrocarbon oxidation. Several hydrocarbon-degrading sulfate-reducing bacteria (SRB) were enriched or isolated from marine sediments. However, in situ active SRB remained largely unknown. In the present thesis, the global distribution and a...

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

    Science.gov (United States)

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

    2013-12-01

    Hong Kong practices seawater toilet flushing covering 80% of the population. A sulfur cycle-based biological nitrogen removal process, the Sulfate reduction, Autotrophic denitrification and Nitrification Integrated (SANI(®)) process, had been developed to close the loop between the hybrid water supply and saline sewage treatment. To enhance this novel process, granulation of a Sulfate-Reducing Up-flow Sludge Bed (SRUSB) reactor has recently been conducted for organic removal and provision of electron donors (sulfide) for subsequent autotrophic denitrification, with a view to minimizing footprint and maximizing operation resilience. This further study was focused on the biological and physicochemical characteristics of the granular sulfate-reducing sludge. A lab-scale SRUSB reactor seeded with anaerobic digester sludge was operated with synthetic saline sewage for 368 days. At 1 h nominal hydraulic retention time (HRT) and 6.4 kg COD/m(3)-d organic loading rate, the SRUSB reactor achieved 90% COD and 75% sulfate removal efficiencies. Granular sludge was observed within 30 days, and became stable after 4 months of operation with diameters of 400-500 μm, SVI5 of 30 ml/g, and extracellular polymeric substances of 23 mg carbohydrate/g VSS. Fluorescence in situ hybridization (FISH) analysis revealed that the granules were enriched with abundant sulfate-reducing bacteria (SRB) as compared with the seeding sludge. Pyrosequencing analysis of the 16S rRNA gene in the sulfate-reducing granules on day 90 indicated that the microbial community consisted of a diverse SRB genera, namely Desulfobulbus (18.1%), Desulfobacter (13.6%), Desulfomicrobium (5.6%), Desulfosarcina (0.73%) and Desulfovibrio (0.6%), accounting for 38.6% of total operational taxonomic units at genera level, with no methanogens detected. The microbial population and physicochemical properties of the granules well explained the excellent performance of the granular SRUSB reactor. Copyright © 2013 Elsevier

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

    Science.gov (United States)

    Goevert, Dennis; Conrad, Ralf

    2008-11-01

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

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

    Science.gov (United States)

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

    2015-02-01

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

  5. Transient exposure to oxygen or nitrate reveals ecophysiology of fermentative and sulfate-reducing benthic microbial populations

    NARCIS (Netherlands)

    Saad, S.; Bhatnagar, S.; Tegetmeyer, H.E.; Geelhoed, J.S.; Strous, M.; Ruff, S.E.

    2017-01-01

    SummaryFor the anaerobic remineralization of organic matter inmarine sediments, sulfate reduction coupled to fer-mentation plays a key role. Here, we enriched sulfate-reducing/fermentative communities from intertidalsediments under defined conditions in continuousculture. We transiently exposed

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

    International Nuclear Information System (INIS)

    Fukunaga, S.; Fujiki, K.; Asano, H.; Yoshikawa, H.

    1995-01-01

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

  7. Anaerobic consortia of fungi and sulfate reducing bacteria in deep granite fractures.

    Science.gov (United States)

    Drake, Henrik; Ivarsson, Magnus; Bengtson, Stefan; Heim, Christine; Siljeström, Sandra; Whitehouse, Martin J; Broman, Curt; Belivanova, Veneta; Åström, Mats E

    2017-07-04

    The deep biosphere is one of the least understood ecosystems on Earth. Although most microbiological studies in this system have focused on prokaryotes and neglected microeukaryotes, recent discoveries have revealed existence of fossil and active fungi in marine sediments and sub-seafloor basalts, with proposed importance for the subsurface energy cycle. However, studies of fungi in deep continental crystalline rocks are surprisingly few. Consequently, the characteristics and processes of fungi and fungus-prokaryote interactions in this vast environment remain enigmatic. Here we report the first findings of partly organically preserved and partly mineralized fungi at great depth in fractured crystalline rock (-740 m). Based on environmental parameters and mineralogy the fungi are interpreted as anaerobic. Synchrotron-based techniques and stable isotope microanalysis confirm a coupling between the fungi and sulfate reducing bacteria. The cryptoendolithic fungi have significantly weathered neighboring zeolite crystals and thus have implications for storage of toxic wastes using zeolite barriers.Deep subsurface microorganisms play an important role in nutrient cycling, yet little is known about deep continental fungal communities. Here, the authors show organically preserved and partly mineralized fungi at 740 m depth, and find evidence of an anaerobic fungi and sulfate reducing bacteria consortium.

  8. BASE COMPOSITION OF THE DEOXYRIBONUCLEIC ACID OF SULFATE-REDUCING BACTERIA.

    Science.gov (United States)

    SIGAL, N; SENEZ, J C; LEGALL, J; SEBALD, M

    1963-06-01

    Sigal, Nicole (Laboratoire de Chimie Bactérienne du CNRS, Marseille, France), Jacques C. Senez, Jean Le Gall, and Madeleine Sebald. Base composition of the deoxyribonucleic acid of sulfate-reducing bacteria. J. Bacteriol. 85:1315-1318. 1963-The deoxyribonucleic acid constitution of several strains of sulfate-reducing bacteria has been analytically determined. The results of these studies show that this group of microorganisms includes at least four subgroups characterized by significantly different values of the adenine plus thymine to guanine plus cytosine ratio. The nonsporulated forms with polar flagellation, containing both cytochrome c(3) and desulfoviridin, are divided into two subgroups. One includes the fresh-water, nonhalophilic strains with base ratio from 0.54 to 0.59, and the other includes the halophilic or halotolerant strains with base ratio from 0.74 to 0.77. The sporulated, peritrichous strains without cytochrome and desulfoviridin ("nigrificans" and "orientis") are distinct from the above two types and differ from each other, having base ratios of 1.20 and 1.43, respectively.

  9. Successive changes in community structure of an ethylbenzene-degrading sulfate-reducing consortium.

    Science.gov (United States)

    Nakagawa, Tatsunori; Sato, Shinya; Yamamoto, Yoko; Fukui, Manabu

    2002-06-01

    The microbial community structure and successive changes in a mesophilic ethylbenzene-degrading sulfate-reducing consortium were for the first time clarified by the denaturing gradient gel electrophoresis (DGGE) analysis of the PCR amplified 16S rRNA gene fragments. At least ten bands on the DGGE gel were detected in the stationary phase. Phylogenetic analysis of the DGGE bands revealed that the consortium consisted of different eubacterial phyla including the delta subgroup of Proteobacteria, the order Sphingobacteriales, the order Spirochaetales, and the unknown bacterium. The most abundant band C was closely related to strain mXyS1, an m-xylene-degrading sulfate-reducing bacterium (SRB), and occurred as a sole band on DGGE gels in the logarithmic growth phase that 40% ethylbenzene was consumed accompanied by sulfide production. During further prolonged incubation, the dominancy of band C did not change. These results suggest that SRB corresponds to the most abundant band C and contributes mainly to the degradation of ethylbenzene coupled with sulfate reduction.

  10. Comparative study on disinfection potency of spore forming bacteria by electron-beam irradiation and gamma-ray irradiation

    International Nuclear Information System (INIS)

    Takizawa, Hironobu; Suzuki, Satoru; Suzuki, Tetsuya; Takama, Kozo; Hayashi, Toru; Yasumoto, Kyoden.

    1990-01-01

    Along with gamma-ray irradiation, electron-beam irradiation (EB) is a method to disinfect microorganisms which cause food decomposition and food-poisoning. The present study was undertaken to compare sterilization efficacy of EB and gamma-ray irradiation on bacterial spores and vegetative cells under various conditions. Spores of Bacillus pumilus, a marker strain for irradiation study, and Bacillus stearothermophilus known as a thermophilic bacteria were irradiated by electron-beam and gamma-ray separately at irradiation dose of 0 to 10 kGy on combination of wet/dry and aerobic/anaerobic conditions. Sterilization effect of irradiation on spores was evaluated by colony counting on agar plates. Results showed that both EB and gamma-ray irradiation gave sufficient sterilization effect on spores, and the sterilization effect increased exponentially with irradiation dose. The sterilization effect of gamma-ray irradiation was higher than that of EB in all cases. Higher disinfection effect was observed under aerobic condition. The present study suggests that oxygen supply in EB is more important than gamma-ray irradiation. No results suggesting that chlorine ion at 0.1 ppm (as available chlorine concentration) enhanced the sterilization efficacy of either EB or gamma-ray irradiation was obtained under any conditions examined. (author)

  11. Comparative study on disinfection potency of spore forming bacteria by electron-beam irradiation and gamma-ray irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Takizawa, Hironobu; Suzuki, Satoru; Suzuki, Tetsuya; Takama, Kozo [Hokkaido Univ., Hakodate (Japan). Faculty of Fisheries; Hayashi, Toru; Yasumoto, Kyoden

    1990-10-01

    Along with gamma-ray irradiation, electron-beam irradiation (EB) is a method to disinfect microorganisms which cause food decomposition and food-poisoning. The present study was undertaken to compare sterilization efficacy of EB and gamma-ray irradiation on bacterial spores and vegetative cells under various conditions. Spores of Bacillus pumilus, a marker strain for irradiation study, and Bacillus stearothermophilus known as a thermophilic bacteria were irradiated by electron-beam and gamma-ray separately at irradiation dose of 0 to 10 kGy on combination of wet/dry and aerobic/anaerobic conditions. Sterilization effect of irradiation on spores was evaluated by colony counting on agar plates. Results showed that both EB and gamma-ray irradiation gave sufficient sterilization effect on spores, and the sterilization effect increased exponentially with irradiation dose. The sterilization effect of gamma-ray irradiation was higher than that of EB in all cases. Higher disinfection effect was observed under aerobic condition. The present study suggests that oxygen supply in EB is more important than gamma-ray irradiation. No results suggesting that chlorine ion at 0.1 ppm (as available chlorine concentration) enhanced the sterilization efficacy of either EB or gamma-ray irradiation was obtained under any conditions examined. (author).

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

    Science.gov (United States)

    Dittmar, Thorsten; Lara, Rubén José

    2001-05-01

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

  13. Hydrogen isotopic messages in sulfate reducer lipids: a recorder of metabolic state?

    Science.gov (United States)

    Bradley, A. S.; Leavitt, W.; Zhou, A.; Cobban, A.; Suess, M.

    2017-12-01

    A significant range in microbial lipid 2H/1H ratios is observed in modern marine sediments. The magnitude of hydrogen isotope fractionation between microbial lipids and growth water (2ɛlipid-H2O) is hypothesized to relate to the central carbon and energy metabolism. These observations raise the possibility for culture independent identification of the dominant metabolic pathways operating in a given environment [Zhang et al. 2009]. One such metabolism we aim to track is microbial sulfate reduction. To-date, sulfate reducing bacteria have been observed to produce lipids that are depleted in fatty acid H-isotope composition, relative to growth water (2ɛlipid-H2O -50 to -175 ‰) [Campbell et al. 2009; Dawson et al. 2015; Osburn et al.], with recent work demonstrating a systematic relationship between lipid/water fractionation and growth rate when the electron-bifurcating NAD(P)(H) transhydrogenase (ebTH) activity was disrupted and the available electron requires the ebTH [Leavitt et al. 2016. Front Microbio]. Recent work in aerobic methylotrophs [Bradley et al. 2014. AGU] implicates non-bifurcating NAD(P)(H) transhydrogenase activity is a critical control on 2ɛlipid-H2O. This suggests a specific mechanism to control the range in fractionation is the ratio of intracellular NADPH/NADH/NADP/NAD in aerobes and perhaps the same in anaerobes with some consideration for FADH/FAD. Fundamentally this implies 2ɛlipid-H2O records intracellular redox state. In our sulfate reducer model system Desulfovibrio alaskensis strain G20 a key component of energy metabolism is the activity of ebTH. Nonetheless, this strain contains two independent copies of the genes, only one of which generates a distinctive isotopic phenotype [Leavitt et al. 2016. Front Microbio]. In this study we extend the recent work in G20 to continuous culture experiments comparing WT to nfnAB-2 transposon interruptions, where both organisms are cultivated continuously, at the rate of the slower growing mutant

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

    Science.gov (United States)

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

    2011-06-01

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

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

    Directory of Open Access Journals (Sweden)

    Xiaoliang Wang

    2009-07-01

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

  16. Adaptation of psychrophilic and psychrotrophic sulfate-reducing bacteria to permanently cold marine environments

    DEFF Research Database (Denmark)

    Isaksen, MF; Jørgensen, BB

    1996-01-01

    environments, In sediment slurries from Antarctica, the metabolic activity of psychrotrophic bacteria was observed with a respiration optimum at 18 to 19 degrees C during short-term incubations, However, over a 1-week incubation, the highest respiration rate was observed at 12.5 degrees C. Growth...... of the bacterial population at the optimal growth temperature could be an explanation for the low temperature optimum of the measured sulfate reduction, The potential for sulfate reduction was highest at temperatures well above the in situ temperature in all experiments, The results frorn sediment incubations were...... compared with those obtained from pure cultures of sulfate-reducing bacteria by using the psychrotrophic strain Itk10 and the mesophilic strain ak30. The psychrotrophic strain reduced sulfate optimally at 28 degrees C in short-term incubations, even though it could not grow at temperatures above 24 degrees...

  17. Growth and chemosensory behavior of sulfate-reducing bacteria in oxygen-sulfide gradients

    DEFF Research Database (Denmark)

    Sass, Andrea M.; Wieland, Andrea Eschemann; Kühl, Michael

    2002-01-01

    Growth and chemotactic behavior in oxic–anoxic gradients were studied with two freshwater and four marine strains of sulfate-reducing bacteria related to the genera Desulfovibrio, Desulfomicrobium or Desulfobulbus. Cells were grown in oxygen–sulfide counter-gradients within tubes filled with agar...... chemotactically to lactate, nitrate, sulfate and thiosulfate, and even sulfide functioned as an attractant. In oxic–anoxic gradients the bacteria moved away from high oxygen concentrations and formed bands at the outer edge of the oxic zone at low oxygen concentration (... to actively change the extension and slope of the gradients by oxygen reduction with lactate or even sulfide as electron donor. Generally, the chemotactic behavior was in agreement with a defense strategy that re-establishes anoxic conditions, thus promoting anaerobic growth and, in a natural community...

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

    Science.gov (United States)

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

    2008-11-01

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

  19. Isolation of sulfate-reducing bacteria from sediments above the deep-subseafloor aquifer.

    Science.gov (United States)

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

    2012-01-01

    On a global scale, crustal fluids fuel a large part of the deep-subseafloor biosphere by providing electron acceptors for microbial respiration. In this study, we examined bacterial cultures from sediments of the Juan de Fuca Ridge, Northeast Pacific (IODP Site U1301). The sediments comprise three distinctive compartments: an upper sulfate-containing zone, formed by bottom-seawater diffusion, a sulfate-depleted zone, and a second (∼140 m thick) sulfate-containing zone influenced by fluid diffusion from the basaltic aquifer. In order to identify and characterize sulfate-reducing bacteria, enrichment cultures from different sediment layers were set up, analyzed by molecular screening, and used for isolating pure cultures. The initial enrichments harbored specific communities of heterotrophic microorganisms. Strains affiliated to Desulfosporosinus lacus, Desulfotomaculum sp., and Desulfovibrio aespoeensis were isolated only from the top layers (1.3-9.1 meters below seafloor, mbsf), while several strains of Desulfovibrio indonesiensis and a relative of Desulfotignum balticum were obtained from near-basement sediments (240-262 mbsf). Physiological tests on three selected strains affiliated to Dv. aespoeensis, Dv. indonesiensis, and Desulfotignum balticum indicated that all reduce sulfate with a limited number of short-chain n-alcohols or fatty acids and were able to ferment either ethanol, pyruvate, or betaine. All three isolates shared the capacity of growing chemolithotrophically with H(2) as sole electron donor. Strain P23, affiliating with Dv. indonesiensis, even grew autotrophically in the absence of any organic compounds. Thus, H(2) might be an essential electron donor in the deep-subseafloor where the availability of organic substrates is limited. The isolation of non-sporeforming sulfate reducers from fluid-influenced layers indicates that they have survived the long-term burial as active populations even after the separation from the seafloor hundreds

  20. Immobilization of cobalt by sulfate-reducing bacteria in subsurface sediments

    Science.gov (United States)

    Krumholz, Lee R.; Elias, Dwayne A.; Suflita, Joseph M.

    2003-01-01

    We investigated the impact of sulfate-reduction on immobilization of metals in subsurface aquifers. Co 2+ was used as a model for heavy metals. Factors limiting sulfate-reduction dependent Co 2+ immobilization were tested on pure cultures of sulfate-reducing bacteria, and in sediment columns from a landfill leachate contaminated aquifer. In the presence of 1 mM Co 2+ , the growth of pure cultures of sulfate-reducing bacteria was not impacted. Cultures of Desulfovibrio desulfuricans, Desulfotomaculum gibsoniae , and Desulfomicrobium hypogeia removed greater than 99.99% of the soluble Co 2+ when CoCl 2 was used with no chelators. The above cultures and Desulfoarcula baarsi removed 98-99.94% of the soluble Co(II) when the metal was complexed with the model ligand nitrilotriacetate (Co-NTA). Factors controlling the rate of sulfate-reduction based Co 2+ precipitation were investigated in sediment-cobalt mixtures. Several electron donors were tested and all but toluene accelerated soluble Co 2+ loss. Ethanol and formate showed the greatest stimulation. All complex nitrogen sources tested slowed and decreased the extent of Co 2+ removal from solution relative to formate-amended sediment incubations. A range of pH values were tested (6.35-7.81), with the more alkaline incubations exhibiting the largest precipitation of Co 2+ . The immobilization of Co 2+ in sediments was also investigated with cores to monitor the flow of Co 2+ through undisturbed sediments. An increase in the amount of Co 2+ immobilized as CoS was observed as sulfate reduction activity was stimulated in flow through columns. Both pure culture and sediment incubation data indicate that stimulation of sulfate reduction is a viable strategy in the immobilization of contaminating metals in subsurface systems.

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

    Science.gov (United States)

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

    1994-01-01

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

  2. Microbiological method for radiation sterilization (III). Development of identification software of spore-forming bacteria by using BBL CRYSTAL GP identification kit

    International Nuclear Information System (INIS)

    Hironiwa, Takayuki; Yamamoto, Yoko; Koshikawa, Tomihiko

    2004-01-01

    The part III in this title series describes the development of software for identification of spore-forming bacteria using the commercially available BBL CRYSTAL GP Identification Kit (Becton, Dickinson and Co., Ltd.), which is essentially for identification of Gram positive bacteria and is not always suitable for the spore-former in the radiation sterilization of medical devices. Isolation and identification of a spore-forming bacterium have to be confirmed by phase-contrast microscopy. The bacteria cultured overnight are to be inoculated in the Kit and cultured for 18-24 hr at 35-37 deg C with the lid attached by substrates for identification. Here, 30 substrates and probability of positive reactions to the substrates have been tested for spore-formers to make the computer software for final identification. The system is possible to identify 13 spp. of Bacillus, 4 of Paenibacillus, 2 of Brevibaccilus and 1 of Virgibacillus, which are the usual bioburden. For possible misidentification, re-isolation of the bacterium, prolonged culture, concentrated inoculation and re-consideration for ranking of identification the software provides are necessary as well as other identification approaches. Thus, as described in this series, the radio-resistance of, and radiation dose for, the bioburden can be evaluated more easily than hitherto, with use of the kits in radiation sterilization. (N.I.)

  3. Transient exposure to oxygen or nitrate reveals ecophysiology of fermentative and sulfate-reducing benthic microbial populations.

    Science.gov (United States)

    Saad, Sainab; Bhatnagar, Srijak; Tegetmeyer, Halina E; Geelhoed, Jeanine S; Strous, Marc; Ruff, S Emil

    2017-12-01

    For the anaerobic remineralization of organic matter in marine sediments, sulfate reduction coupled to fermentation plays a key role. Here, we enriched sulfate-reducing/fermentative communities from intertidal sediments under defined conditions in continuous culture. We transiently exposed the cultures to oxygen or nitrate twice daily and investigated the community response. Chemical measurements, provisional genomes and transcriptomic profiles revealed trophic networks of microbial populations. Sulfate reducers coexisted with facultative nitrate reducers or aerobes enabling the community to adjust to nitrate or oxygen pulses. Exposure to oxygen and nitrate impacted the community structure, but did not suppress fermentation or sulfate reduction as community functions, highlighting their stability under dynamic conditions. The most abundant sulfate reducer in all cultures, related to Desulfotignum balticum, appeared to have coupled both acetate- and hydrogen oxidation to sulfate reduction. We describe a novel representative of the widespread uncultured candidate phylum Fermentibacteria (formerly candidate division Hyd24-12). For this strictly anaerobic, obligate fermentative bacterium, we propose the name ' U Sabulitectum silens' and identify it as a partner of sulfate reducers in marine sediments. Overall, we provide insights into the function of fermentative, as well as sulfate-reducing microbial communities and their adaptation to a dynamic environment. © 2017 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

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

    Science.gov (United States)

    Li, Yongchao; Hu, Xiaoxian; Ren, Bozhi

    2016-01-01

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

  5. Performance evaluation and microbial community analysis of the function and fate of ammonia in a sulfate-reducing EGSB reactor.

    Science.gov (United States)

    Wang, Depeng; Liu, Bo; Ding, Xinchun; Sun, Xinbo; Liang, Zi; Sheng, Shixiong; Du, Lingfeng

    2017-10-01

    Ammonia is widely distributed in sulfate-reducing bioreactor dealing with sulfate wastewater, which shows potential effect on the metabolic pathway of sulfate and ammonia. This study investigates the sulfate-reducing efficiency and microbial community composition in the sulfate-reducing EGSB reactor with the increasing ammonia loading. Results indicated that, compared with low ammonia loading (166-666 mg/L), the sulfate and organic matter removal efficiencies were improved gradually with the appropriate ammonia loading (1000-2000 mg/L), which increased from 63.58 ± 3.81 to 71.08 ± 1.36% and from 66.24 ± 1.32 to 81.88 ± 1.83%, respectively. Meanwhile, with the appropriate ratio of ammonia and sulfate (1.5-3.0) and hydraulic retention time (21 h), the sulfate-reducing anaerobic ammonia oxidation (SRAO) process was occurred efficiently, inducing the accumulation of S 0 (270 mg/L) and the simultaneous ammonia removal (70.83%) in EGSB reactor. Moreover, the key sulfate-reducing bacteria (SRB) (Desulfovibrio) and denitrification bacteria (Pseudomonas and Alcaligenes) were responsible for the sulfate and nitrogen removal in these phases, which accounted for 3.66-5.54 and 3.85-9.13%, respectively. However, as the ammonia loading higher than 3000 mg/L (phases 9 and 10), the sulfate-reducing efficiency was decreased to only 28.3 ± 1.26% with the ammonia removal rate of 18.4 ± 3.37% in the EGSB reactor. Meanwhile, the predominant SRB in phases 9 and 10 were Desulfomicrobium (1.22-1.99%) and Desulfocurvus (4.0-5.46%), and the denitrification bacteria accounted for only 0.88% (phase 10), indicating the low nitrogen removal rate.

  6. Sulfate-Reducing Prokaryotes from North Sea Oil reservoirs; organisms, distribution and origin

    Energy Technology Data Exchange (ETDEWEB)

    Beeder, Janiche

    1996-12-31

    During oil production in the North Sea, anaerobic seawater is pumped in which stimulates the growth of sulphate-reducing prokaryotes that produce hydrogen sulphide. This sulphide causes major health hazards, economical and operational problems. As told in this thesis, several strains of sulphate reducers have been isolated from North Sea oil field waters. Antibodies have been produced against these strains and used to investigate the distribution of sulphate reducers in a North Sea oil reservoir. The result showed a high diversity among sulphate reducers, with different strains belonging to different parts of the reservoir. Some of these strains have been further characterized. The physiological and phylogenetic characterization showed that strain 7324 was an archaean. Strain A8444 was a bacterium, representing a new species of a new genus. A benzoate degrading sulphate reducing bacterium was isolated from injection water, and later the same strain was detected in produced water. This is the first field observations indicating that sulphate reducers are able to penetrate an oil reservoir. It was found that the oil reservoir contains a diverse population of thermophilic sulphate reducers able to grow on carbon sources in the oil reservoir, and to live and grow in this extreme environment of high temperature and pressure. The mesophilic sulphate reducers are established in the injection water system and in the reservoir near the injection well during oil production. The thermophilic sulphate reducers are able to grow in the reservoir prior to, as well as during production. It appears that the oil reservoir is a natural habitat for thermophilic sulphate reducers and that they have been present in the reservoir long before production started. 322 refs., 9 figs., 11 tabs.

  7. Sulfate-Reducing Prokaryotes from North Sea Oil reservoirs; organisms, distribution and origin

    Energy Technology Data Exchange (ETDEWEB)

    Beeder, Janiche

    1997-12-31

    During oil production in the North Sea, anaerobic seawater is pumped in which stimulates the growth of sulphate-reducing prokaryotes that produce hydrogen sulphide. This sulphide causes major health hazards, economical and operational problems. As told in this thesis, several strains of sulphate reducers have been isolated from North Sea oil field waters. Antibodies have been produced against these strains and used to investigate the distribution of sulphate reducers in a North Sea oil reservoir. The result showed a high diversity among sulphate reducers, with different strains belonging to different parts of the reservoir. Some of these strains have been further characterized. The physiological and phylogenetic characterization showed that strain 7324 was an archaean. Strain A8444 was a bacterium, representing a new species of a new genus. A benzoate degrading sulphate reducing bacterium was isolated from injection water, and later the same strain was detected in produced water. This is the first field observations indicating that sulphate reducers are able to penetrate an oil reservoir. It was found that the oil reservoir contains a diverse population of thermophilic sulphate reducers able to grow on carbon sources in the oil reservoir, and to live and grow in this extreme environment of high temperature and pressure. The mesophilic sulphate reducers are established in the injection water system and in the reservoir near the injection well during oil production. The thermophilic sulphate reducers are able to grow in the reservoir prior to, as well as during production. It appears that the oil reservoir is a natural habitat for thermophilic sulphate reducers and that they have been present in the reservoir long before production started. 322 refs., 9 figs., 11 tabs.

  8. Synergistic action of cinnamaldehyde with silver nanoparticles against spore-forming bacteria: a case for judicious use of silver nanoparticles for antibacterial applications

    Directory of Open Access Journals (Sweden)

    Ghosh IN

    2013-12-01

    Full Text Available Indro Neil Ghosh,1,* Supriya Deepak Patil,1,* Tarun Kumar Sharma,1,2 Santosh Kumar Srivastava,1 Ranjana Pathania,1 Naveen Kumar Navani11Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand, 2Center for Biodesign and Diagnostics, Translational Health Science and Technology Institute, Gurgaon Haryana, India*These authors contributed equally to this workAbstract: Silver has long been advocated as an effective antimicrobial. However, toxicity issues with silver have led to limited use of silver in nanoform, especially for food preservation. With the aim of exploring combinatorial options that could increase the antibacterial potency of silver nanoparticles and reduce the effective dosage of silver, we evaluated the extent of synergy that a combination of silver nanoparticles and an essential oil representative (cinnamaldehyde could offer. A battery of gram-positive and gram-negative bacterial strains was utilized for antibacterial assays, and extents of synergism were calculated from fractional inhibitory concentration indices. The activity of nanoparticles was greatly enhanced when utilized in the presence of cinnamaldehyde. We observed combinatorial effects that were strongly additive against all the bacterial strains tested, and genuine synergy was found against spore forming Bacillus cereus and Clostridium perfringens – bacterial strains associated with release of cytotoxins in contaminated food and known for their persistence. Bacterial kill curve analysis revealed a very fast bactericidal action when a combination of two agents was used. The electron and atomic force microscopy also revealed extensive damage to the bacterial cell envelop in the presence of both agents. We also performed hemolysis assays to investigate and approximate the extent of toxicity exhibited by the two agents, and observed no adverse effect at the concentrations required for synergy. This study shows that safe levels of silver in

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

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hong; Yu, Tong, E-mail: tong.yu@ualberta.ca; Liu, Yang, E-mail: yang.liu@ualberta.ca

    2015-12-01

    Biofilm reactors were constructed to grow stratified multispecies biofilm in oil sands process-affected water (OSPW) supplemented with growth medium. The development of sulfate reducing bacteria (SRB) within the biofilm and the biofilm treatment of OSPW were evaluated. The community structure and potential activity of SRB in the biofilm were investigated with H{sub 2}S microsensor measurements, dsrB gene-based denaturing gradient gel electrophoresis (DGGE), and the real time quantitative polymerase chain reaction (qPCR). Multispecies biofilm with a thickness of 1000 μm was successfully developed on engineered biocarriers. H{sub 2}S production was observed in the deeper anoxic zone of the biofilm from around 750 μm to 1000 μm below the bulk water-biofilm interface, revealing sulfate reduction in the deeper zone of the stratified biofilm. The biofilm removed chemical oxygen demand (COD), sulfate, and nitrogen. The study expands current knowledge of biofilm treatment of OSPW and the function of anaerobic SRB in OSPW biofilm, and thus provides information for future bioreactor development in the reclamation of OSPW. - Graphical abstract: The development of sulfate reducing bacteria (SRB) within Oil Sands Process-affected Water (OSPW) biofilm and the biofilm treatment of OSPW were evaluated by Liu and coworkers. Combined microsensor and molecular biology techniques were utilized in this study. Their results demonstrated that multispecies biofilm with a thickness of 1000 μm was successfully developed on engineered biocarriers. H{sub 2}S production was observed in the deeper anoxic zone of the biofilm from around 750 μm to 1000 μm below the bulk water-biofilm interface, revealing sulfate reduction in the deeper zone of the biofilm. The biofilm removed chemical oxygen demand (COD), sulfate, and nitrogen. - Highlights: • Biofilm in oil sands wastewater was developed on engineered biocarriers. • Bacterial community and in situ activity of SRB were studied in the

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

    International Nuclear Information System (INIS)

    Liu, Hong; Yu, Tong; Liu, Yang

    2015-01-01

    Biofilm reactors were constructed to grow stratified multispecies biofilm in oil sands process-affected water (OSPW) supplemented with growth medium. The development of sulfate reducing bacteria (SRB) within the biofilm and the biofilm treatment of OSPW were evaluated. The community structure and potential activity of SRB in the biofilm were investigated with H 2 S microsensor measurements, dsrB gene-based denaturing gradient gel electrophoresis (DGGE), and the real time quantitative polymerase chain reaction (qPCR). Multispecies biofilm with a thickness of 1000 μm was successfully developed on engineered biocarriers. H 2 S production was observed in the deeper anoxic zone of the biofilm from around 750 μm to 1000 μm below the bulk water-biofilm interface, revealing sulfate reduction in the deeper zone of the stratified biofilm. The biofilm removed chemical oxygen demand (COD), sulfate, and nitrogen. The study expands current knowledge of biofilm treatment of OSPW and the function of anaerobic SRB in OSPW biofilm, and thus provides information for future bioreactor development in the reclamation of OSPW. - Graphical abstract: The development of sulfate reducing bacteria (SRB) within Oil Sands Process-affected Water (OSPW) biofilm and the biofilm treatment of OSPW were evaluated by Liu and coworkers. Combined microsensor and molecular biology techniques were utilized in this study. Their results demonstrated that multispecies biofilm with a thickness of 1000 μm was successfully developed on engineered biocarriers. H 2 S production was observed in the deeper anoxic zone of the biofilm from around 750 μm to 1000 μm below the bulk water-biofilm interface, revealing sulfate reduction in the deeper zone of the biofilm. The biofilm removed chemical oxygen demand (COD), sulfate, and nitrogen. - Highlights: • Biofilm in oil sands wastewater was developed on engineered biocarriers. • Bacterial community and in situ activity of SRB were studied in the biofilm.

  11. Sulfate-reducing bacteria influence the nucleation and growth of mackinawite and greigite

    Science.gov (United States)

    Picard, Aude; Gartman, Amy; Clarke, David R.; Girguis, Peter R.

    2018-01-01

    Sedimentary iron sulfide minerals play a key role in maintaining the oxygenation of Earth's atmosphere over geological timescales; they also record critical geochemical information that can be used to reconstruct paleo-environments. On modern Earth, sedimentary iron sulfide mineral formation takes places in low-temperature environments and requires the production of free sulfide by sulfate-reducing microorganisms (SRM) under anoxic conditions. Yet, most of our knowledge on the properties and formation pathways of iron sulfide minerals, including pyrite, derives from experimental studies performed in abiotic conditions, and as such the role of biotic processes in the formation of sedimentary iron sulfide minerals is poorly understood. Here we investigate the role of SRM in the nucleation and growth of iron sulfide minerals in laboratory experiments. We set out to test the hypothesis that SRM can influence Fe-S mineralization in ways other than providing sulfide through the comparison of the physical properties of iron sulfide minerals precipitated in the presence and in the absence of the sulfate-reducing bacterium Desulfovibrio hydrothermalis AM13 under well-controlled conditions. X-ray diffraction and microscopy analyses reveal that iron sulfide minerals produced in the presence of SRM exhibit unique morphology and aggregate differently than abiotic minerals formed in media without cells. Specifically, mackinawite growth is favored in the presence of both live and dead SRM, when compared to the abiotic treatments tested. The cell surface of live and dead SRM, and the extracellular polymers produced by live cells, provide templates for the nucleation of mackinawite and favor mineral growth. The morphology of minerals is however different when live and dead cells are provided. The transformation of greigite from mackinawite occurred after several months of incubation only in the presence of live SRM, suggesting that SRM might accelerate the kinetics of greigite

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

    International Nuclear Information System (INIS)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2013-10-01

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

  14. Deeply-sourced formate fuels sulfate reducers but not methanogens at Lost City hydrothermal field.

    Science.gov (United States)

    Lang, Susan Q; Früh-Green, Gretchen L; Bernasconi, Stefano M; Brazelton, William J; Schrenk, Matthew O; McGonigle, Julia M

    2018-01-15

    Hydrogen produced during water-rock serpentinization reactions can drive the synthesis of organic compounds both biotically and abiotically. We investigated abiotic carbon production and microbial metabolic pathways at the high energy but low diversity serpentinite-hosted Lost City hydrothermal field. Compound-specific 14 C data demonstrates that formate is mantle-derived and abiotic in some locations and has an additional, seawater-derived component in others. Lipids produced by the dominant member of the archaeal community, the Lost City Methanosarcinales, largely lack 14 C, but metagenomic evidence suggests they cannot use formate for methanogenesis. Instead, sulfate-reducing bacteria may be the primary consumers of formate in Lost City chimneys. Paradoxically, the archaeal phylotype that numerically dominates the chimney microbial communities appears ill suited to live in pure hydrothermal fluids without the co-occurrence of organisms that can liberate CO 2 . Considering the lack of dissolved inorganic carbon in such systems, the ability to utilize formate may be a key trait for survival in pristine serpentinite-hosted environments.

  15. Desulfotignum phosphitoxidans sp. nov., a new marine sulfate reducer that oxidizes phosphite to phosphate.

    Science.gov (United States)

    Schink, Bernhard; Thiemann, Volker; Laue, Heike; Friedrich, Michael W

    2002-05-01

    A new sulfate-reducing bacterium was isolated from marine sediment with phosphite as sole electron donor and CO(2) as the only carbon source. Strain FiPS-3 grew slowly, with doubling times of 3-4 days, and oxidized phosphite, hydrogen, formate, acetate, fumarate, pyruvate, glycine, glutamate, and other substrates nearly completely, with concomitant reduction of sulfate to sulfide. Acetate was formed as a side product to a small extent. Glucose, arabinose, and proline were partly oxidized and partly fermented to acetate plus propionate. Growth with phosphite, hydrogen, or formate was autotrophic. Also, in the presence of sulfate, CO dehydrogenase was present, and added acetate did not increase growth rates or growth yields. In the absence of sulfate, phosphite oxidation was coupled to homoacetogenic acetate formation, with growth yields similar to those in the presence of sulfate. Cells were small rods, 0.6 - 0.8 x 2-4 microm in size, and gram-negative, with a G+C content of 53.9 mol%. They contained desulforubidin, but no desulfoviridin. Based on sequence analysis of the 16S rRNA gene and the sulfite reductase genes dsrAB, strain FiPS-3 was found to be closely related to Desulfotignum balticum. However, physiological properties differed in many points from those of D. balticum. These findings justify the establishment of a new species, Desulfotignum phosphitoxidans.

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

    Science.gov (United States)

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

    2015-11-01

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

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

    Directory of Open Access Journals (Sweden)

    Ulrike eJaekel

    2015-02-01

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

  18. Accelerated methanogenesis from aliphatic and aromatic hydrocarbons under iron- and sulfate-reducing conditions.

    Science.gov (United States)

    Siegert, Michael; Cichocka, Danuta; Herrmann, Steffi; Gründger, Friederike; Feisthauer, Stefan; Richnow, Hans-Hermann; Springael, Dirk; Krüger, Martin

    2011-02-01

    The impact of four electron acceptors on hydrocarbon-induced methanogenesis was studied. Methanogenesis from residual hydrocarbons may enhance the exploitation of oil reservoirs and may improve bioremediation. The conditions to drive the rate-limiting first hydrocarbon-oxidizing steps for the conversion of hydrocarbons into methanogenic substrates are crucial. Thus, the electron acceptors ferrihydrite, manganese dioxide, nitrate or sulfate were added to sediment microcosms acquired from two brackish water locations. Hexadecane, ethylbenzene or 1-(13)C-naphthalene were used as model hydrocarbons. Methane was released most rapidly from incubations amended with ferrihydrite and hexadecane. Ferrihydrite enhanced only hexadecane-dependent methanogenesis. The rates of methanogenesis were negatively affected by sulfate and nitrate at concentrations of more than 5 and 1 mM, respectively. Metal-reducing Geobacteraceae and potential sulfate reducers as well as Methanosarcina were present in situ and in vitro. Ferrihydrite addition triggered the growth of Methanosarcina-related methanogens. Additionally, methane was removed concomitantly by anaerobic methanotrophy. ANME-1 and -2 methyl coenzyme M reductase genes were detected, indicating anaerobic methanotrophy as an accompanying process [Correction added 16 December after online publication: 'methyl coenzyme A' changed to 'methyl coenzyme M' in this sentence]. The experiments presented here demonstrate the feasibility of enhancing methanogenic alkane degradation by ferrihydrite or sulfate addition in different geological settings. © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

    Wall, Judy D. [Univ. of Missouri, Columbia, MO (United States)

    2014-12-23

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

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

    Science.gov (United States)

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

    2016-01-15

    CdS nanoparticles were synthesized with an environmentally friendly method by taking advantage of the characteristic metabolic process of sulfate-reducing bacteria (SRB), and used as fluorescence labels for SRB detection. The presence of CdS nanoparticles was observed within and immediately surrounded bacterial cells, indicating CdS nanoparticles were synthesized both intracellularly and extracellularly. Moreover, fluorescent properties of microbial synthesized CdS nanoparticles were evaluated for SRB detection, and a linear relationship between fluorescence intensity and the logarithm of bacterial concentration was obtained in the range of from 1.0×10(2) to 1.0×10(7)cfu mL(-1). The proposed SRB detection method avoided the use of biological bio-recognition elements which are easy to lose their specific recognizing abilities, and the bacterial detection time was greatly shortened compared with the widely used MPN method which would take up to 15 days to accomplish the detection process. Copyright © 2015 Elsevier B.V. All rights reserved.

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

    Science.gov (United States)

    Zhang, Mingliang; Wang, Haixia; Han, Xuemei

    2016-07-01

    Novel immobilized sulfate-reducing bacteria (SRB) beads were prepared for the treatment of synthetic acid mine drainage (AMD) containing high concentrations of Fe, Cu, Cd and Zn using up-flow anaerobic packed-bed bioreactor. The tolerance of immobilized SRB beads to heavy metals was significantly enhanced compared with that of suspended SRB. High removal efficiencies of sulfate (61-88%) and heavy metals (>99.9%) as well as slightly alkaline effluent pH (7.3-7.8) were achieved when the bioreactor was fed with acidic influent (pH 2.7) containing high concentrations of multiple metals (Fe 469 mg/L, Cu 88 mg/L, Cd 92 mg/L and Zn 128 mg/L), which showed that the bioreactor filled with immobilized SRB beads had tolerance to AMD containing high concentrations of heavy metals. Partially decomposed maize straw was a carbon source and stabilizing agent in the initial phase of bioreactor operation but later had to be supplemented by a soluble carbon source such as sodium lactate. The microbial community in the bioreactor was characterized by denaturing gradient gel electrophoresis (DGGE) and sequencing of partial 16S rDNA genes. Synergistic interaction between SRB (Desulfovibrio desulfuricans) and co-existing fermentative bacteria could be the key factor for the utilization of complex organic substrate (maize straw) as carbon and nutrients source for sulfate reduction. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2009-02-18

    Abundance and seasonal dynamics of sulfate-reducing bacteria (SRB), in general, and of extreme halophilic SRB (belonging to Desulfocella halophila) in particular, were examined in highly saline industrial wastewater evaporation ponds over a forty one month period. Industrial wastewater was sampled and the presence of SRB was determined by quantitative real-time PCR (qPCR) with a set of primers designed to amplify the dissimilatory sulfite reductase (dsrA) gene. SRB displayed higher abundance during the summer (10(6)-10(8) targets ml(-1)) and lower abundance from the autumn-spring (10(3)-10(5) targets ml(-1)). However, addition of concentrated dissolved organic matter into the evaporation ponds during winter immediately resulted in a proliferation of SRB, despite the lower wastewater temperature (12-14 degrees C). These results indicate that the qPCR approach can be used for rapid measurement of SRB to provide valuable information about the abundance of SRB in harsh environments, such as highly saline industrial wastewaters. Low level of H2S has been maintained over five years, which indicates a possible inhibition of SRB activity, following artificial salination (approximately 16% w/v of NaCl) of wastewater evaporation ponds, despite SRB reproduction being detected by qPCR.

  3. Isotope fractionation during the anaerobic consumption of acetate by methanogenic and sulfate-reducing microorganisms

    Science.gov (United States)

    Gövert, D.; Conrad, R.

    2009-04-01

    During the anaerobic degradation of organic matter in anoxic sediments and soils acetate is the most important substrate for the final step in production of CO2 and/or CH4. Sulfate-reducing bacteria (SRB) and methane-producing archaea both compete for the available acetate. Knowledge about the fractionation of 13C/12C of acetate carbon by these microbial groups is still limited. Therefore, we determined carbon isotope fractionation in different cultures of acetate-utilizing SRB (Desulfobacter postgatei, D. hydrogenophilus, Desulfobacca acetoxidans) and methanogens (Methanosarcina barkeri, M. acetivorans). Including literature values (e.g., Methanosaeta concilii), isotopic enrichment factors (epsilon) ranged between -35 and +2 permil, possibly involving equilibrium isotope effects besides kinetic isotope effects. The values of epsilon were dependent on the acetate-catabolic pathway of the particular microorganism, the methyl or carboxyl position of acetate, and the relative availability or limitation of the substrate acetate. Patterns of isotope fractionation in anoxic lake sediments and rice field soil seem to reflect the characteristics of the microorganisms actively involved in acetate catabolism. Hence, it might be possible using environmental isotopic information to determine the type of microbial metabolism converting acetate to CO2 and/or CH4.

  4. Both sulfate-reducing bacteria and Enterobacteriaceae take part in marine biocorrosion of carbon steel.

    Science.gov (United States)

    Bermont-Bouis, D; Janvier, M; Grimont, P A D; Dupont, I; Vallaeys, T

    2007-01-01

    In order to evaluate the part played in biocorrosion by microbial groups other than sulfate-reducing bacteria (SRB), we characterized the phylogenetic diversity of a corrosive marine biofilm attached to a harbour pile structure as well as to carbon steel surfaces (coupons) immersed in seawater for increasing time periods (1 and 8 months). We thus experimentally checked corroding abilities of defined species mixtures. Microbial community analysis was performed using both traditional cultivation techniques and polymerase chain reaction cloning-sequencing of 16S rRNA genes. Community structure of biofilms developing with time on immersed coupons tended to reach after 8 months, a steady state similar to the one observed on a harbour pile structure. Phylogenetic affiliations of isolates and cloned 16S rRNA genes (rrs) indicated that native biofilms (developing after 1-month immersion) were mainly colonized by gamma-proteobacteria. Among these, Vibrio species were detected in majority with molecular methods while cultivation techniques revealed dominance of Enterobacteriaceae such as Citrobacter, Klebsiella and Proteus species. Conversely, in mature biofilms (8-month immersion and pile structure), SRB, and to a lesser extent, spirochaetes were dominant. Corroding activity detection assays confirmed that Enterobacteriaceae (members of the gamma-proteobacteria) were involved in biocorrosion of metallic material in marine conditions. In marine biofilms, metal corrosion may be initiated by Enterobacteriaceae.

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

    Science.gov (United States)

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

    2011-06-01

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

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

    Science.gov (United States)

    Xu, Dake; Li, Yingchao; Gu, Tingyue

    2016-08-01

    Biocorrosion is also known as microbiologically influenced corrosion (MIC). Most anaerobic MIC cases can be classified into two major types. Type I MIC involves non-oxygen oxidants such as sulfate and nitrate that require biocatalysis for their reduction in the cytoplasm of microbes such as sulfate reducing bacteria (SRB) and nitrate reducing bacteria (NRB). This means that the extracellular electrons from the oxidation of metal such as iron must be transported across cell walls into the cytoplasm. Type II MIC involves oxidants such as protons that are secreted by microbes such as acid producing bacteria (APB). The biofilms in this case supply the locally high concentrations of oxidants that are corrosive without biocatalysis. This work describes a mechanistic model that is based on the biocatalytic cathodic sulfate reduction (BCSR) theory. The model utilizes charge transfer and mass transfer concepts to describe the SRB biocorrosion process. The model also includes a mechanism to describe APB attack based on the local acidic pH at a pit bottom. A pitting prediction software package has been created based on the mechanisms. It predicts long-term pitting rates and worst-case scenarios after calibration using SRB short-term pit depth data. Various parameters can be investigated through computer simulation. Copyright © 2016 Elsevier B.V. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Morgan N Price

    2014-10-01

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

  8. Hydrogen and acetate cycling in two sulfate-reducing sediments: Buzzards Bay and Town Cove, Massachusetts

    Energy Technology Data Exchange (ETDEWEB)

    Novelli, P.C. (SUNY, Stony Brook, NY (USA) Univ. of Colorado, Boulder (USA)); Michelson, A.R.; Scranton, M.I. (SUNY, Stony Brook, NY (USA)); Banta, G.T.; Hobbie, J.E. (Marine Biological Laboratory, Woods, Hole, MA (USA)); Howarth, R.W. (Cornell Univ., Ithaca, NY (USA))

    1988-10-01

    Molecular hydrogen and acetate are believed to be key intermediates in the anaerobic remineralization of organic carbon. The authors have made measurements of the cycling of both these compounds in two marine sediments: the bioturbated sediments of Buzzards Bay, Mass., and the much more reducing sediments of Town Cove, Orleans, Mass. Hydrogen concentrations are similar in these environments (from less than 5 to 30 nM), and are within the range previously reported for coastal sediments. However, apparent hydrogen production rates differ by a factor of 60 between these two sediments and at both sites show strong correlation with measured rates of sulfate reduction. Acetate concentrations generally increased with depth in both environments; this increase was greater in Buzzards Bay (22.5 to 71.5 {mu}M) than in Town Cove (26 to 44 {mu}M). Acetate oxidation rates calculated from measured concentrations and {sup 14}C-acetate consumption rate constants suggest that the measured acetate was not all available to sulfate-reducing bacteria. Using the measured sulfate reduction rates, they estimate that between 2% and 100% of the measured acetate pool is biologically available, and that the bioavailable pool decreases with depth. A diagenetic model of the total acetate concentration suggests that consumption may be first order with respect to only a fraction of the total pool.

  9. Initial cytotoxicity assays of media for sulfate-reducing bacteria: An endodontic biopharmaceutical product under development.

    Science.gov (United States)

    Heggendorn, Fabiano Luiz; Silva, Gabriela Cristina de Carvalho; Cardoso, Elisama Azevedo; Castro, Helena Carla; Gonçalves, Lúcio Souza; Dias, Eliane Pedra; Lione, Viviane de Oliveira Freitas; Lutterbach, Márcia Teresa Soares

    2016-01-01

    This study assessed the cell viability of the inoculation vehicle of BACCOR (a combination of sulfate-reducing bacteria plus a culture media for bacteria), a biopharmaceutical product under development for dental use as aid in fractured endodontic file removal from the root canal. Different culture media for bacteria were evaluated: modified Postgate E (MCP-E mod), Modified Postgate E without Agar-agar (MCP-E w/Ag), Postgate C with Agar-agar (MCP-C Ag) and Postgate C without Agar-agar (MCP-C w/Ag). Cytotoxicity was quantified by the MTT test, exposing L929 and Vero cell lines to the vehicles over 24 h. The exposure of L929 cell line to MCP-E w/Ag resulted in biocompatibility (52% cell viability), while the exposure of the Vero kidney line revealed only MCP-E mod as cytotoxic. When diluted, all the vehicles showed biocompatibility with both cell lines. MCP-E w/Ag was the vehicle chosen for BACCOR, because of its biocompatibility with the cells used.

  10. Sulfate reducing bacteria detection in gas pipelines; Deteccao de bacterias redutoras de sulfato em gasodutos

    Energy Technology Data Exchange (ETDEWEB)

    Lutterbach, Marcia Teresa S.; Oliveira, Ana Lucia C. de; Cavalcanti, Eduardo H. de S. [Instituto Nacional de Tecnologia (INT), Rio de Janeiro, RJ (Brazil). Div. de Corrosao e Degradacao]. E-mails: marciasl@int.gov.br; analucia@int.gov.br; eduardoh@int.gov.br

    2004-07-01

    Microbiology induced corrosion (MIC) process associated with sulfate reducing bacteria (BRS) are one of the most important matter of concern for the oil and gas industry as 77% of failures have been attributed this sort of degradation. Corrosion products found present in gas transportation pipelines, the so-called 'black-powder' problem, are also a nuisance and source of economic losses for the gas industry. According to the literature, the incidence of black-powder can be ascribed to the metabolism of BRS that can be found in the gas environment. Integrity monitoring programs of gas pipelines adopt pigging as an important tool for internal corrosion monitoring. Solid residue such as the black-powder, collected by pigging, as well as the condensed, can be seen as a very valuable samples for microbiological analyses that can be used to detect and quantify bacteria related to the incidence of MIC processes. In the present work results concerning samples collected by pigging and condensed are presented. Small populations of viable BRS have been found in the pipeline. It can be seen that the inclusion of microbiological analyses of solid and liquid residues as a complementary action in the integrity monitoring programs adopted by gas transportation industry can be very helpful on the decision making concerning preventive and corrective actions to be taken in order to maintain the CIM processes under control. (author)

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

    Science.gov (United States)

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

    2015-10-01

    Extracellular polymeric substances (EPS) play an important role in the treatment of acid mine drainage (AMD) by sulfate-reducing bacteria (SRB). In this paper, Desulfovibrio desulfuricans was used as the test strain to explore the effect of heavy metals on the components and adsorption ability of EPS. Fourier-transform infrared (FTIR) spectroscopy analysis results showed that heavy metals did not influence the type of functional groups of EPS. Potentiometric titration results indicated that the acidic constants (pKa) of the EPS fell into three ranges of 3.5-4.0, 5.9-6.7, and 8.9-9.8. The adsorption site concentrations of the surface functional groups also increased. Adsorption results suggested that EPS had a specific binding affinity for the dosed heavy metal, and that EPS extracted from the Zn(2+)-dosed system had a higher binding affinity for all heavy metals. Additionally, Zn(2+) decreased the inhibitory effects of Cd(2+) and Cu(2+) on the SRB. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    International Nuclear Information System (INIS)

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

    1999-01-01

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

  13. Inhibitory concentrations of 2,4D and its possible intermediates in sulfate reducing biofilms

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Cruz, Ulises [Department of Biotechnology, Environmental Science and Technology, Universidad Autonoma Metropolitana-Iztapalapa, Ave. San Rafael Atlixco 186, Vicentina, 09340 D.F. (Mexico); Celis, Lourdes B. [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica, Camino a la Presa San Jose 2055, Lomas 4a. Seccion, 78216 San Luis Potosi, S.L.P. (Mexico); Poggi, Hector [Department of Biotechnology and Bioengineering, CINVESTAV, Av. Instituto Politecnico Nacional 2508, Col. San Pedro Zacatenco, 07360 D.F. (Mexico); Meraz, Monica, E-mail: meraz@xanum.uam.mx [Department of Biotechnology, Environmental Science and Technology, Universidad Autonoma Metropolitana-Iztapalapa, Ave. San Rafael Atlixco 186, Vicentina, 09340 D.F. (Mexico)

    2010-07-15

    Different concentrations of the herbicide 2,4-dichlorophenoxyacetic acid (2,4D) and its possible intermediates such as 2,4-dichlorophenol (2,4DCP), 4-chlorophenol (4CP), 2-chlorophenol (2CP) and phenol, were assayed to evaluate the inhibitory effect on sulfate and ethanol utilization in a sulfate reducing biofilm. Increasing concentrations of the chlorophenolic compounds showed an adverse effect on sulfate reduction rate and ethanol conversion to acetate, being the intermediate 2,4DCP most toxic than the herbicide. The monochlorophenol 4CP (600 ppm) caused the complete cessation of sulfate reduction and ethanol conversion. The ratio of the electron acceptor to the electron donor utilized as well as the sulfate utilization volumetric rates, diminished when chlorophenols and phenol concentrations were increased, pointing out to the inhibition of the respiratory process and electrons transfer. The difference found in the IC{sub 50} values obtained was due to the chemical structure complexity of the phenolic compounds, the number of chlorine atoms as much as the chlorine atom position in the phenol ring. The IC{sub 50} values (ppm) indicated that the acute inhibition on the biofilm was caused by 2,4DCP (17.4) followed by 2,4D (29.0), 2CP (99.8), 4CP (108.0) and phenol (143.8).

  14. Comparison between sodium hypochlorite and copper sulfate reducer in lightening of overexposed working length radiographs

    Directory of Open Access Journals (Sweden)

    Fatemeh Ezoddini Ardakani

    2015-12-01

    Full Text Available Objectives: The aims of this study were to test whether lightening of the overexposed radiographs improve determination of endodontic files length and whether lightened radiographs are comparable with ideally exposed radiographs. Material and Methods: Four dried human skull coated with soft tissue-equivalent wax used for exposing radiographs of the upper molars. First, the endodontic file was placed in full length of the root and four series of radiographs obtained. The time to expose the first series was unchanged (standard group but increased for the other three series.  Two series of overexposed radiographs set as test groups (one lightened with copper sulfate reducer and the other lightened with sodium hypochlorite and one series set as control group. Then the endodontic file placed 2mm short in the root and four series of radiographs obtained like the former. A viewer evaluated radiographs. ROC curves were obtained and areas under the curves were calculated. Sensitivity, specificity and Cohen’s kappa was calculated. Results: The average area under ROC curves was 1, 0.995,1 and 0.643 for the standard, Copper sulfate, sodium hypochlorite and the control group, respectively. Sodium hypochlorite show a better performance in terms of sensitivity and specificity compared to Copper sulfate. Differences between the test radiographs and standard and control radiographs were significant (p

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

    Science.gov (United States)

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

    2011-12-01

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

  16. Cathodic protection of XL 52 steel under the influence of sulfate reducing bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Esquivel, R. Garcia [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas No. 152, Col. San Bartolo Atepehuacan, Mexico, D.F. 07730 (Mexico); Departamento de lngenieria Metalurgica, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, 04510 Mexico, D.F. (Mexico); Olivares, G. Zavala; Gayosso, M.J. Hernandez; Trejo, A. Gayosso [Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas No. 152, Col. San Bartolo Atepehuacan, Mexico, D.F. 07730 (Mexico)

    2011-01-15

    The effect of sulfate reducing bacteria (SRB) upon the cathodic protection of XL 52 steel was determined, in order to identify if the potential value of -0.950 V versus copper/copper sulfate electrode is good enough to protect the metal surface. During the experiments, different operational parameters were monitored: hydrogen sulfide production, iron concentration, electrolyte alkalinity, microorganisms' population, as well as the metal surface damage. At the same time, the corrosion rate was determined using two electrochemical techniques: polarization resistance (PR) and electrochemical impedance spectroscopy (EIS). According to the results, it was observed that the protection potential of -0.950 V versus copper/copper sulfate electrode is not enough to control the microbiologically induced corrosion. This situation is reinforced by the fact that significant iron concentration was found in the electrolyte. The microbiological activity is not affected by the protection potential. On the contrary, the population growth is slightly strengthened. The alkalinity generated by the applied potential did not stop the SRB growth. A type of localized corrosion was developed during the experiments with microorganisms, even when the protection potential was applied to the system. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

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

    Science.gov (United States)

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

  18. Influence of Sulfate-Reducing Bacteria on the Corrosion Residual Strength of an AZ91D Magnesium Alloy

    Science.gov (United States)

    Zhu, Xianyong; Liu, Yaohui; Wang, Qiang; Liu, Jiaan

    2014-01-01

    In this paper, the corrosion residual strength of the AZ91D magnesium alloy in the presence of sulfate-reducing bacteria is studied. In the experiments, the chemical composition of corrosion film was analyzed by a scanning electron microscope with energy dispersive X-ray spectroscopy. In addition, a series of instruments, such as scanning electronic microscope, pH-meter and an AG-10TA materials test machine, were applied to test and record the morphology of the corrosion product, fracture texture and mechanical properties of the AZ91D magnesium alloy. The experiments show that the sulfate-reducing bacteria (SRB) play an important role in the corrosion process of the AZ91D magnesium alloy. Pitting corrosion was enhanced by sulfate-reducing bacteria. Corrosion pits are important defects that could lead to a significant stress concentration in the tensile process. As a result, sulfate-reducing bacteria influence the corrosion residual strength of the AZ91D magnesium alloy by accelerating pitting corrosion. PMID:28788236

  19. Properties of thermophilic microorganisms

    International Nuclear Information System (INIS)

    Ljungdahl, L.G.

    1984-01-01

    Microorganisms are called thermophilic or extreme thermophilic (caldo-active) if they grow and reproduce over 47 0 C and 70 0 C, respectively. A survey of growth characteristics of thermophiles is presented and it includes those which also live at extreme pH. The prevalent but not completely emcompassing theory of the ability of thermophiles to grow at high temperatures is that they have macromolecules and cell organelles with high thermostability. Work on some proteins and cell organelles from thermophiles is reviewed. The thermostabilities of these components are compared with those of the living cells, and factors which may govern optimum as well as minimum growth temperatures of microorganisms are discussed. Examples are from the literature but also include enzymes involved in tetrahydrofolate metabolism and other proteins of acetogenic therhmophilic bacteria which are presently studied in the author's laboratory

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

    Directory of Open Access Journals (Sweden)

    D. Lovley

    2012-03-01

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

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

    Science.gov (United States)

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

    2013-08-13

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

  2. Diversity and characterization of sulfate-reducing bacteria in groundwater at a uranium mill tailings site

    International Nuclear Information System (INIS)

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

    2000-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Ayala-Parra, Pedro; Sierra-Alvarez, Reyes; Field, James A., E-mail: jimfield@email.arizona.edu

    2016-05-05

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

  4. Behavior of plutonium interacting with bentonite and sulfate-reducing anaerobic bacteria

    International Nuclear Information System (INIS)

    Kudo, A.; Zheng, J.; Cayer, I.; Fujikawa, Y.; Yoshikawa, H.; Ito, M.

    1997-01-01

    The interactions between sulfate reducing anaerobic bacteria and plutonium, with or without bentonite present, were investigated using distribution coefficients [Kd (ml/g)] as an index of the radionuclide behavior. Plutonium Kds for living bacteria varied within a large range, from 1,804 to 112,952, depending on the pH, while the Kds ranged from 1,180 to 5,931 for dead bacteria. In general, living bacteria had higher plutonium Kds than dead bacteria. Furthermore, the higher Kd values of 39,677 to 106,915 for living bacteria were obtained for a pH range between 6.83 and 8.25, while no visible pH effect was observed for dead bacteria. These Kd values were obtained using tracers for both 236 Pu and 239 Pu, which can check the experimental procedures and mass balance. Another comparison was conducted for plutonium Kd values of mixtures of living bacteria with bentonite and sterilized bacteria with bentonite. The range of Kd values for the non-sterilized bacteria with bentonite were 1,194 to 83,648 while Kd values for the sterilized bacteria with bentonite were from 624 to 17,236. Again, the Kd values for the living bacteria with bentonite were higher than those of sterilized bacteria with bentonite. In other words, the presence of living anaerobic bacteria with bentonite increased, by roughly 50 times, the Kd values of 239 Pu when compared to the mixture of dead bacteria with bentonite. The results indicate that the effects of anaerobic bacteria within the engineered barrier system (in this case bentonite) will play a significant role in the behavior of plutonium in geologic repositories

  5. CHROMIUM(VI REDUCTION BY A MIXED CULTURE OF SULFATE REDUCING BACTERIA DEVELOPED IN COLUMN REACTOR

    Directory of Open Access Journals (Sweden)

    Cynthia Henny

    2008-03-01

    Full Text Available A lactate enriched mixed sulfate reducing bacteria (SRB culture was examined for the reduction of Cr(VI in a continuous flow system. The influent was mineral salts media added with lactate and sulfate with amounts of 8 and 6 mM respectively as electron donor and electron acceptor. The SRB culture was allowed to stabilize in the column before adding the Cr(VI to the influent. Chromium and sulfate reduction and lactate oxidation were examined by measuring the concentrations of Cr(Vl, sulfate and lactate in the influent and the effluent over time. The experiment was discontinued when Cr(VI concentration in the effiuent was breakthrough. In the absence of Cr(VI, sulfate was not completely reduced in the column, although lactate was completely oxidized and acetate as an intermediate product was not often detected. Almost all of Cr(VI loaded was reduced in the column seeded with the SRB culture at influent Cr(VI concentrations of 192,385 and769 mM. There was no significant Cr(VI loss in the control column, indicating that Cr(VI removal was due to the reduction of Cr(VI to Cr (lll by the SRB culture. The instantaneous Cr(VI removal decreased to a minimum of 32%, 24 days after the influent Cr(VI concentration was increased to 1540 mM, ancl sulfate removal efficiency decreased to a minimum of 17%. The SRB population in the column decreased 100 days after C(VI was added to the column. The total mass of Cr(VI reduced was approximately 878 mmol out of 881 mmol of Cr(Vl loaded in 116 days. The results clearly show that our developed SRB culture could reduced Cr(Vl considerably.

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

    International Nuclear Information System (INIS)

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

    1991-01-01

    The biogeochemical cycling of mercury has received considerable attention because of the toxicity of methylmercury, its bioaccumulation in biota, and its biomagnification in aquatic food chains. The formation of methylmercury is mediated primarily by microorganisms. Demethylation of monomethylmercury in freshwater and estuarine sediments and in bacterial cultures was investigated with 14 CH 3 HgI. Under anaerobiosis, results with inhibitors indicated partial involvement of both sulfate reducers and methanogens, the former dominated estuarine sediments, while both were active in freshwaters. Aerobes were the most significant demethylators in estuarine sediments, but were unimportant in freshwater sediments. Products of anaerobic demthylation were mainly 14 CO 2 as well as lesser amounts of 14 CH 4 . Acetogenic activity resulted in fixation of some 14 CO 2 produced from 14 CH 3 HgI into acetate. Aerobic demethylation in estuarine sediments produced only 14 CH 4 , while aerobic demethylation in freshwater sediments produced small amounts of both 14 CH 4 and 14 CO 2 . Two species of Desulfovibrio produced only traces of 14 CH 4 from 14 CH 3 HgI, while a culture of a methylotrophic methanogen formed traces of 14 CO 2 and 14 CH 4 when grown on trimethylamine in the presence of the 14 CH 3 HgI. These results indicate that both aerobes and anaerobes demethylate mercury in sediments, but that either group may dominate in a particular sediment type. Aerobic demethylation in the estuarine sediments appeared to proceed by the previously characterized organomercurial-lyase pathway, because methane was the sole product. This indicates the presence of an oxidative pathway, possibly one in which methylmercury serves as an analog of one-carbon substrates

  7. Desulfofrigus sp. prevails in sulfate-reducing dilution cultures from sediments of the Benguela upwelling area.

    Science.gov (United States)

    Kraft, Beate; Engelen, Bert; Goldhammer, Tobias; Lin, Yu-Shih; Cypionka, Heribert; Könneke, Martin

    2013-04-01

    Sediments of coastal upwelling areas are generally characterized by a high content of organic carbon that is mainly degraded via anaerobic microbial processes including sulfate reduction as a major terminal oxidation step. Despite the high importance of sulfate reduction in these sediments, the identity of sulfate-reducing bacteria (SRB) has remained almost unknown. Here, we applied a cultivation-based approach using selective enrichment conditions to study the diversity and distribution of active SRB in sediments along a transect perpendicular to the continental slope off the coast of Namibia (Meteor-cruise M76/1). To promote growth of the most abundant SRB, dilution series were prepared and amended with hydrogen, acetate, or a mixture of monomers representing typical substrates for SRB. Growth of SRB could be detected in the presence of all electron donors and from sediment down to 4 m depth. 16S rRNA gene-based DGGE analysis and sequencing revealed the predominance of SRB related to psychrophiles in particular to the genus Desulfofrigus, which made up 1 % of the total microbial community, accounting for an absolute abundance of up to 4.8 × 10(7)  cells mL(-1) . In general, the abundance of cultured SRB changed with depth and between the different sampling sites and correlated with the content of organic carbon as previously reported. Growth of chemolithotrophic SRB in relatively high dilution steps and the enrichment of methanogens as well as acetogens from deeper sediment point to a competition between hydrogen-utilizing microbial processes and their biogeochemical significance in deep sediment layers of the Benguela upwelling area. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

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

    Science.gov (United States)

    Garrelfs, Julia

    2014-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Alawi, Mashal; Lerm, Stephanie; Wuerdemann, Hilke [Helmholtz-Zentrum Potsdam, GFZ Deutsches GeoForschungsZentrum, Internationales Geothermiezentrum, Potsdam (Germany); Vetter, Alexandra [Helmholtz-Zentrum Potsdam, GFZ Deutsches GeoForschungsZentrum, Organische Geochemie, Potsdam (Germany); Wolfgramm, Markus [Geothermie Neubrandenburg GmbH (GTN), Neubrandenburg (Germany); Seibt, Andrea [BWG Geochemische Beratung GbR, Neubrandenburg (Germany)

    2011-06-15

    Abstract Enhanced process understanding of engineered geothermal systems is a prerequisite to optimize plant reliability and economy. We investigated microbial, geochemical and mineralogical aspects of a geothermal groundwater system located in the Molasse Basin by fluid analysis. Fluids are characterized by temperatures ranging from 61 C to 103 C, salinities from 600 to 900 mg/l and a dissolved organic carbon content (DOC) between 6.4 to 19.3 mg C/l. The microbial population of fluid samples was analyzed by genetic fingerprinting techniques based on PCR-amplified 16S rRNA- and dissimilatory sulfite reductase genes. Despite of the high temperatures, microbes were detected in all investigated fluids. Fingerprinting and DNA sequencing enabled a correlation to metabolic classes and biogeochemical processes. The analysis revealed a broad diversity of sulfate-reducing bacteria. Overall, the detection of microbes known to be involved in biocorrosion and mineral precipitation indicates that microorganisms could play an important role for the understanding of processes in engineered geothermal systems. (orig.) [German] Die Verbesserung des Prozessverstaendnisses ist eine grundlegende Voraussetzung fuer eine Optimierung der Betriebssicherheit und der Oekonomie geothermischer Anlagen in Bezug auf die Partikelbildung und Korrosion. Daher wurden Prozessfluide einer Anlage im Molassebecken unter mikrobiologischen, geochemischen und mineralogischen Gesichtspunkten untersucht. Die Fluidtemperatur der vor und nach dem Waermetauscher entnommenen Fluide betrug zwischen 103 C und 61 C. Die Salinitaet variierte zwischen 600 und 900 mg/l und der geloeste organische Kohlenstoff (DOC) lag zwischen 6,4 und 19,3 mg C/l. Die mikrobielle Lebensgemeinschaft in der Anlage wurde mithilfe einer genetischen Fingerprinting-Methode charakterisiert. Hierzu wurde das 16S rRNA Gen sowie die fuer sulfatreduzierende Bakterien (SRB) spezifische dissimilatorische Sulfitreduktase untersucht. In allen

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

    Science.gov (United States)

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

    2012-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Jackson Z Lee

    2014-02-01

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

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

    Science.gov (United States)

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

    2015-07-21

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

  13. Sulfur isotopic and proteomic profiles of sulfate reducers grown under differential steady-states

    Science.gov (United States)

    Leavitt, W.; Venceslau, S.; Waldbauer, J.; Smith, D. A.; Boidi, F. J.; Bradley, A. S.

    2016-12-01

    Microbial sulfate reducers (MSR) drive the Earth's biogeochemical sulfur cycle. At the heart of this energy metabolism is a cascade of redox transformations coupling organic carbon and/or hydrogen oxidation to the dissimilatory reduction of sulfate to sulfide. The product sulfide is depleted in the heavier isotopes of sulfur, relative to the reactant sulfate, consistent with a normal kinetic isotope effect. However, the magnitude of the net fractionation during MSR can range over a range of 70 permil, consistent with a multi-step set of reactions. This range in MSR fractionation has been shown to mainly depend on: i) the cell-specific sulfate reduction rate (csSRR), and ii) the ambient sulfate concentration. However, the fractionation under identical conditions differs among strains (Bradley et al. 2016. Geobio), and so must also be mediated by strain-specific processes, such as the nature and quantity of individual proteins involved in sulfate reduction, electron transport, and growth. In recent work we have examined the influence of electron donor, electron acceptor, and co-limitation under controlled steady-state culture conditions in order better inform models of MSR isotope fractionation, and the physiological and isotopic response to differential environmental forcings (e.g. Leavitt et al. (2013) PNAS). Recent models of the fractionation response to MSR rate (c.f. Bradley 2016; Wing & Halevy, 2016) make specific predictions for the responses of the cellular metabolome and proteome. Here we compare the steady-state S-isotopic fractionation and proteome of `fast' versus `slow' grown D. vulgaris, using replicate chemostats under electron donor limitation. We observe clear and statistically robust changes in some key central MSR and C-metabolism enzymes, though a host of the critical energy-transfer enzymes show no statistically discernable change. We discuss these results in light of recent theoretical advances and their relevance to modern and ancient

  14. Disguised as a Sulfate Reducer: Growth of the Deltaproteobacterium Desulfurivibrio alkaliphilus by Sulfide Oxidation with Nitrate.

    Science.gov (United States)

    Thorup, Casper; Schramm, Andreas; Findlay, Alyssa J; Finster, Kai W; Schreiber, Lars

    2017-07-18

    This study demonstrates that the deltaproteobacterium Desulfurivibrio alkaliphilus can grow chemolithotrophically by coupling sulfide oxidation to the dissimilatory reduction of nitrate and nitrite to ammonium. Key genes of known sulfide oxidation pathways are absent from the genome of D. alkaliphilus Instead, the genome contains all of the genes necessary for sulfate reduction, including a gene for a reductive-type dissimilatory bisulfite reductase (DSR). Despite this, growth by sulfate reduction was not observed. Transcriptomic analysis revealed a very high expression level of sulfate-reduction genes during growth by sulfide oxidation, while inhibition experiments with molybdate pointed to elemental sulfur/polysulfides as intermediates. Consequently, we propose that D. alkaliphilus initially oxidizes sulfide to elemental sulfur, which is then either disproportionated, or oxidized by a reversal of the sulfate reduction pathway. This is the first study providing evidence that a reductive-type DSR is involved in a sulfide oxidation pathway. Transcriptome sequencing further suggests that nitrate reduction to ammonium is performed by a novel type of periplasmic nitrate reductase and an unusual membrane-anchored nitrite reductase. IMPORTANCE Sulfide oxidation and sulfate reduction, the two major branches of the sulfur cycle, are usually ascribed to distinct sets of microbes with distinct diagnostic genes. Here we show a more complex picture, as D. alkaliphilus , with the genomic setup of a sulfate reducer, grows by sulfide oxidation. The high expression of genes typically involved in the sulfate reduction pathway suggests that these genes, including the reductive-type dissimilatory bisulfite reductases, are also involved in as-yet-unresolved sulfide oxidation pathways. Finally, D. alkaliphilus is closely related to cable bacteria, which grow by electrogenic sulfide oxidation. Since there are no pure cultures of cable bacteria, D. alkaliphilus may represent an

  15. Sulfate-reducing bacteria slow intestinal transit in a bismuth-reversible fashion in mice.

    Science.gov (United States)

    Ritz, N L; Lin, D M; Wilson, M R; Barton, L L; Lin, H C

    2017-01-01

    Hydrogen sulfide (H 2 S) serves as a mammalian cell-derived gaseous neurotransmitter. The intestines are exposed to a second source of this gas by sulfate-reducing bacteria (SRB). Bismuth subsalicylate binds H 2 S rendering it insoluble. The aim of this study was to test the hypothesis that SRB may slow intestinal transit in a bismuth-reversible fashion. Eighty mice were randomized to five groups consisting of Live SRB, Killed SRB, SRB+Bismuth, Bismuth, and Saline. Desulfovibrio vulgaris, a common strain of SRB, was administered by gavage at the dose of 1.0 × 10 9 cells along with rhodamine, a fluorescent dye. Intestinal transit was measured 50 minutes after gavage by euthanizing the animals, removing the small intestine between the pyloric sphincter and the ileocecal valve and visualizing the distribution of rhodamine across the intestine using an imaging system (IVIS, Perkin-Elmer). Intestinal transit (n=50) was compared using geometric center (1=minimal movement, 100=maximal movement). H 2 S concentration (n=30) was also measured when small intestinal luminal content was allowed to generate this gas. The Live SRB group had slower intestinal transit as represented by a geometric center score of 40.2 ± 5.7 when compared to Saline: 73.6 ± 5.7, Killed SRB: 77.9 ± 6.9, SRB+Bismuth: 81.0 ± 2.0, and Bismuth: 73.3 ± 4.2 (Pfashion in mice. Our results demonstrate that intestinal transit is slowed by SRB and this effect could be abolished by H 2 S-binding bismuth. © 2016 John Wiley & Sons Ltd.

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

    International Nuclear Information System (INIS)

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

    2016-01-01

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

  17. Copper (II) Removal In Anaerobic Continuous Column Reactor System By Using Sulfate Reducing Bacteria

    Science.gov (United States)

    Bilgin, A.; Jaffe, P. R.

    2017-12-01

    Copper is an essential element for the synthesis of the number of electrons carrying proteins and the enzymes. However, it has a high level of toxicity. In this study; it is aimed to treat copper heavy metal in anaerobic environment by using anaerobic continuous column reactor. Sulfate reducing bacteria culture was obtained in anaerobic medium using enrichment culture method. The column reactor experiments were carried out with bacterial culture obtained from soil by culture enrichment method. The system is operated with continuous feeding and as parallel. In the first rector, only sand was used as packing material. The first column reactor was only fed with the bacteria nutrient media. The same solution was passed through the second reactor, and copper solution removal was investigated by continuously feeding 15-600 mg/L of copper solution at the feeding inlet in the second reactor. When the experiment was carried out by adding the 10 mg/L of initial copper concentration, copper removal in the rate of 45-75% was obtained. In order to determine the use of carbon source during copper removal of mixed bacterial cultures in anaerobic conditions, total organic carbon TOC analysis was used to calculate the change in carbon content, and it was calculated to be between 28% and 75%. When the amount of sulphate is examined, it was observed that it changed between 28-46%. During the copper removal, the amounts of sulphate and carbon moles were equalized and more sulfate was added by changing the nutrient media in order to determine the consumption of sulphate or carbon. Accordingly, when the concentration of added sulphate is increased, it is calculated that between 35-57% of sulphate is spent. In this system, copper concentration of up to 15-600 mg / L were studied.

  18. Physiology of thermophilic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Ljungdahl, L G

    1979-01-01

    Thermophilic micro-organisms have all of the properties normally found in mesophilic micro-organisms. These include metabolic pathways, regulatory mechanisms such as allosteric or feedback control, repression and induction of protein synthesis, growth yields and metabolic rates. The main difference between thermophiles and mesophiles is the former's capacity to grow at high temperatures. The basis for this capacity is the thermophile's capability to synthesize proteins, complex structures and membranes that are stable or are stabilized and functional at thermophilic temperatures. It is proposed that the maximum and minimum growth temperatures are normally determined by properties associated with proteins, and that the membrane plays a lesser role in determining these temperatures. Enzymes and other proteins from thermophiles, except for having higher thermostability, are very similar to corresponding proteins from mesophiles. The higher thermostability is generally dependent on subtle changes in the composition and sequence of the amino acids and rarely dependent on non-proteinaceous factors. Although over 100 proteins have been purified from thermophiles and compared with corresponding proteins from mesophiles, the exact nature of the higher thermostability has yet to be determined in a protein from a thermophile.

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

    Science.gov (United States)

    Chen, Guocun

    The influence of sulfate-reducing bacteria (SRB) on the passivity of type 304 and 317L stainless steels (SS) was investigated by x-ray photoelectron spectroscopy (XPS), microbiological and electrochemical techniques. Samples were exposed to SRB, and then the resultant surfaces were analyzed by XPS, and the corrosion resistance by potentiodynamic polarization in deaerated 0.1 M HCl. To further understand their passivity, the SRB-exposed samples were analyzed by XPS after potentiostatic polarization at a passive potential in the hydrochloric solution. The characterization was performed under two surface conditions: unrinsed and rinsed by deaerated alcohol and deionized water. Comparisons were made with control samples immersed in uninoculated medium. SRB caused a severe loss of the passivity of 304 SS through sulfide formation and possible additional activation to form hexavalent chromium. The sulfides included FeS, FeS_2, Cr_2S _3, NiS and possibly Fe_ {rm 1-x}S. The interaction took place nonuniformly, resulting in undercutting of the passive film and preferential hydration of inner surface layers. The bacterial activation of the Cr^{6+ }^ecies was magnified by subsequent potentiostatic polarization. In contrast, 317L SS exhibited a limited passivity. The sulfides were formed mainly in the outer layers. Although Cr^{6+}^ecies were observed after the exposure, they were dissolved upon polarization. Since 317L SS has a higher Mo content, its higher passivity was ascribed to Mo existing as molybdate on the surface and Mo^{5+} species in the biofilm. Consequently, the interaction of SRB with Mo was studied. It was observed that molybdate could be retained on the surfaces of Mo coupons by corrosion products. In the presence of SRB, however, a considerable portion of the molybdate interacted with intermediate sulfur -containing proteins, forming Mo(V)-S complexes and reducing bacterial growth and sulfate reduction. The limited insolubility of the Mo(V)-S complexes in 0

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

    Science.gov (United States)

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

    2012-12-01

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

  1. Slippery liquid-infused porous surfaces fabricated on aluminum as a barrier to corrosion induced by sulfate reducing bacteria

    International Nuclear Information System (INIS)

    Wang, Peng; Lu, Zhou; Zhang, Dun

    2015-01-01

    Highlights: • Slippery liquid-infused porous surfaces (SLIPS) were fabricated over aluminum. • SLIPS depress the adherence of sulfate reducing bacteria in static seawater. • SLIPS inhibit the microbiological corrosion of aluminum in static seawater. • The possible microbiological corrosion protection mechanism of SLIPS is proposed. - Abstract: Microbiological corrosion induced by sulfate reducing bacteria (SRB) is one of the main threatens to the safety of marine structure. To reduce microbiological corrosion, slippery liquid infused porous surfaces (SLIPS) were designed and fabricated on aluminum substrate by constructing rough aluminum oxide layer, followed by fluorination of the rough layer and infiltration with lubricant. The as-fabricated SLIPS were characterized with wettability measurement, SEM and XPS. Their resistances to microbiological corrosion induced by SRB were evaluated with fluorescence microscopy and electrochemical measurement. It was demonstrated that they present high resistance to bacteria adherence and the resultant microbiological corrosion in static seawater

  2. Synergetic treatment of uranium-bearing waste water with sulfate reducing bacteria and zero-valent iron

    International Nuclear Information System (INIS)

    Zhou Quanyu; Tan Kaixuan; Zeng Sheng; Liu Dong

    2009-01-01

    The treatment of uranium-bearing wastewater from uranium mine and using microorganism to treat wastewater were paid much attention to environmental researchers. Based on column experiments, we investigated the potential using sulfate reducing bacteria (SRB) and zero-valent iron (ZVI) to synergetic treat contamination in wastewater such as sulfate, uranium, etc. SRB+ZVI can effectively remove contamination U(VI) and SO 4 2- in wastewater. The removal rate is 99.4% and 86.2% for U(VI) and SO 4 2- , respectively. The pH of wastewater can be basified to neutral. U(VI) and SO 4 2- as electron acceptor of sulfate reducing bacteria are removed by biological reduction. The corrosion of ZVI is benefit to enhance the pH of wastewater, forms anaerobic reducing environment, strengthens survival and metabolism reaction of SRB, and plays a synergetic enhancement. (authors)

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

    Energy Technology Data Exchange (ETDEWEB)

    Rittman, Bruce; Zhou, Chen; Vannela, Raveender

    2013-12-31

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

  4. Microbial Corrosion of API 5L X-70 Carbon Steel by ATCC 7757 and Consortium of Sulfate-Reducing Bacteria

    OpenAIRE

    Abdullah, Arman; Yahaya, Nordin; Md Noor, Norhazilan; Mohd Rasol, Rosilawati

    2014-01-01

    Various cases of accidents involving microbiology influenced corrosion (MIC) were reported by the oil and gas industry. Sulfate reducing bacteria (SRB) have always been linked to MIC mechanisms as one of the major causes of localized corrosion problems. In this study, SRB colonies were isolated from the soil in suspected areas near the natural gas transmission pipeline in Malaysia. The effects of ATCC 7757 and consortium of isolated SRB upon corrosion on API 5L X-70 carbon steel coupon were i...

  5. Methanogenic H2 syntrophy among thermophiles: a model of metabolism, adaptation and survival in the subsurface

    Science.gov (United States)

    Topcuoglu, B. D.; Stewart, L. C.; Butterfield, D. A.; Huber, J. A.; Holden, J. F.

    2016-12-01

    Approximately 1 giga ton (Gt, 1015 g) of CH4 is formed globally per year from H2, CO2 and acetate through methanogenesis, largely by methanogens growing in syntrophic association with anaerobic microbes that hydrolyze and ferment biopolymers. However, our understanding of methanogenesis in hydrothermal regions of the subseafloor and potential syntrophic methanogenesis at thermophilic temperatures (i.e., >50°C) is nascent. In this study, the growth of natural assemblages of thermophilic methanogens from Axial Seamount was primarily limited by H2 availability. Heterotrophs supported thermophilic methanogenesis by H2 syntrophy in microcosm incubations of hydrothermal fluids at 55°C and 80°C supplemented with tryptone only. Based on 16S rRNA gene sequencing, only heterotrophic archaea that produce H2, H2-consuming methanogens, and sulfate reducing archaea were found in 80°C tryptone microcosms from Marker 113 vent. No bacteria were found. In 55°C tryptone microcosms, sequences were found from H2-producing bacteria and H2-consuming methanogens and sulfate-reducing bacteria. In order to model the impact of H2 syntrophy at hyperthemophilic temperatures, a co-culture was established consisting of the H2-producing hyperthermophilic heterotroph Thermococcus paralvinellae and a H2-consuming hyperthermophilic methanogen Methanocaldococcus bathoardescens. When grown alone in a chemostat, the growth rates and steady-state cell concentrations of T. paralvinellae decreased significantly when a high H2 (70 µM) background was present. H2 inhibition was ameliorated by the production of formate, but in silico modeling suggests less energetic yield for the cells. H2 syntrophy relieved H2 inhibition for both the heterotroph and the methanogenic partners. The results demonstrate that thermophilic H2 syntrophy can support methanogenesis within natural microbial assemblages and may be an important alternative energy source for thermophilic autotrophs in marine geothermal environments.

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

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhao; Yang, Yuyin; Dai, Yu; Xie, Shuguang, E-mail: xiesg@pku.edu.cn

    2015-04-09

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

  7. Temperature and pressure adaptation of a sulfate reducer from the deep subsurface

    Directory of Open Access Journals (Sweden)

    Katja eFichtel

    2015-10-01

    Full Text Available Microbial life in deep marine subsurface faces increasing temperatures and hydrostatic pressure with depth. In this study, we have examined growth characteristics and temperature-related adaptation of the Desulfovibrio indonesiensis strain P23 to the in situ pressure of 30 MPa. The strain originates from the deep subsurface of the eastern flank of the Juan de Fuca Ridge (IODP Site U1301. The organism was isolated at 20 °C and atmospheric pressure from ~61 °C-warm sediments approximately five meters above the sediment-basement interface. In comparison to standard laboratory conditions (20 °C and 0.1 MPa, faster growth was recorded when incubated at in situ pressure and high temperature (45 °C, while cell filamentation was induced by further compression. The maximum growth temperature shifted from 48°C at atmospheric pressure to 50°C under high-pressure conditions. Complementary cellular lipid analyses revealed a two-step response of membrane viscosity to increasing temperature with an exchange of unsaturated by saturated fatty acids and subsequent change from branched to unbranched alkyl moieties. While temperature had a stronger effect on the degree of fatty acid saturation and restructuring of main phospholipids, pressure mainly affected branching and length of side chains. The simultaneous decrease of temperature and pressure to ambient laboratory conditions allowed the cultivation of our moderately thermophilic strain. This may in turn be one key to a successful isolation of microorganisms from the deep subsurface adapted to high temperature and pressure.

  8. Biocorrosive Thermophilic Microbial Communities in Alaskan North Slope Oil Facilities

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, Kathleen E.; Gieg, Lisa M.; Parisi, Victoria A.; Tanner, Ralph S.; Green Tringe, Susannah; Bristow, Jim; Suflita, Joseph M.

    2009-09-16

    Corrosion of metallic oilfield pipelines by microorganisms is a costly but poorly understood phenomenon, with standard treatment methods targeting mesophilic sulfatereducing bacteria. In assessing biocorrosion potential at an Alaskan North Slope oil field, we identified thermophilic hydrogen-using methanogens, syntrophic bacteria, peptideand amino acid-fermenting bacteria, iron reducers, sulfur/thiosulfate-reducing bacteria and sulfate-reducing archaea. These microbes can stimulate metal corrosion through production of organic acids, CO2, sulfur species, and via hydrogen oxidation and iron reduction, implicating many more types of organisms than are currently targeted. Micromolar quantities of putative anaerobic metabolites of C1-C4 n-alkanes in pipeline fluids were detected, implying that these low molecular weight hydrocarbons, routinely injected into reservoirs for oil recovery purposes, are biodegraded and provide biocorrosive microbial communities with an important source of nutrients.

  9. Diversity and abundance of sulfate-reducing microorganisms in the sulfate and methane zones of a marine sediment, Black Sea RID A-8182-2008

    DEFF Research Database (Denmark)

    Leloup, Julie; Loy, Alexander; Knab, Nina J.

    2007-01-01

    branching sequences which might represent Gram-positive spore-forming sulfate- and/or sulfite-reducing microorganisms. We thus hypothesize that terminal carbon mineralization in surface sediments of the Black Sea is largely due to the sulfate reduction activity of previously hidden SRM. Although these novel...

  10. Thermophilic lignocellulose deconstruction.

    Science.gov (United States)

    Blumer-Schuette, Sara E; Brown, Steven D; Sander, Kyle B; Bayer, Edward A; Kataeva, Irina; Zurawski, Jeffrey V; Conway, Jonathan M; Adams, Michael W W; Kelly, Robert M

    2014-05-01

    Thermophilic microorganisms are attractive candidates for conversion of lignocellulose to biofuels because they produce robust, effective, carbohydrate-degrading enzymes and survive under harsh bioprocessing conditions that reflect their natural biotopes. However, no naturally occurring thermophile is known that can convert plant biomass into a liquid biofuel at rates, yields and titers that meet current bioprocessing and economic targets. Meeting those targets requires either metabolically engineering solventogenic thermophiles with additional biomass-deconstruction enzymes or engineering plant biomass degraders to produce a liquid biofuel. Thermostable enzymes from microorganisms isolated from diverse environments can serve as genetic reservoirs for both efforts. Because of the sheer number of enzymes that are required to hydrolyze plant biomass to fermentable oligosaccharides, the latter strategy appears to be the preferred route and thus has received the most attention to date. Thermophilic plant biomass degraders fall into one of two categories: cellulosomal (i.e. multienzyme complexes) and noncellulosomal (i.e. 'free' enzyme systems). Plant-biomass-deconstructing thermophilic bacteria from the genera Clostridium (cellulosomal) and Caldicellulosiruptor (noncellulosomal), which have potential as metabolic engineering platforms for producing biofuels, are compared and contrasted from a systems biology perspective. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  11. Acetogenic and Sulfate-Reducing Bacteria Inhabiting the Rhizoplane and Deep Cortex Cells of the Sea Grass Halodule wrightii†

    Science.gov (United States)

    Küsel, Kirsten; Pinkart, Holly C.; Drake, Harold L.; Devereux, Richard

    1999-01-01

    Recent declines in sea grass distribution underscore the importance of understanding microbial community structure-function relationships in sea grass rhizospheres that might affect the viability of these plants. Phospholipid fatty acid analyses showed that sulfate-reducing bacteria and clostridia were enriched in sediments colonized by the sea grasses Halodule wrightii and Thalassia testudinum compared to an adjacent unvegetated sediment. Most-probable-number analyses found that in contrast to butyrate-producing clostridia, acetogens and acetate-utilizing sulfate reducers were enriched by an order of magnitude in rhizosphere sediments. Although sea grass roots are oxygenated in the daytime, colorimetric root incubation studies demonstrated that acetogenic O-demethylation and sulfidogenic iron precipitation activities were tightly associated with washed, sediment-free H. wrightii roots. This suggests that the associated anaerobes are able to tolerate exposure to oxygen. To localize and quantify the anaerobic microbial colonization, root thin sections were hybridized with newly developed 33P-labeled probes that targeted (i) low-G+C-content gram-positive bacteria, (ii) cluster I species of clostridia, (iii) species of Acetobacterium, and (iv) species of Desulfovibrio. Microautoradiography revealed intercellular colonization of the roots by Acetobacterium and Desulfovibrio species. Acetogenic bacteria occurred mostly in the rhizoplane and outermost cortex cell layers, and high numbers of sulfate reducers were detected on all epidermal cells and inward, colonizing some 60% of the deepest cortex cells. Approximately 30% of epidermal cells were colonized by bacteria that hybridized with an archaeal probe, strongly suggesting the presence of methanogens. Obligate anaerobes within the roots might contribute to the vitality of sea grasses and other aquatic plants and to the biogeochemistry of the surrounding sediment. PMID:10543830

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

    Science.gov (United States)

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

    2010-08-01

    The anaerobic oxidation of methane (AOM) with sulfate as terminal electron acceptor is mediated by consortia of methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB). Whereas three clades of ANME have been repeatedly studied with respect to phylogeny, key genes and genomic capabilities, little is known about their sulfate-reducing partner. In order to identify the partner of anaerobic methanotrophs of the ANME-2 clade, bacterial 16S rRNA gene libraries were constructed from cultures highly enriched for ANME-2a and ANME-2c in consortia with Deltaproteobacteria of the Desulfosarcina/Desulfococcus group (DSS). Phylogenetic analysis of those and publicly available sequences from AOM sites supported the hypothesis by Knittel and colleagues that the DSS partner belongs to the diverse SEEP-SRB1 cluster. Six subclusters of SEEP-SRB1, SEEP-SRB1a to SEEP-SRB1f, were proposed and specific oligonucleotide probes were designed. Using fluorescence in situ hybridization on samples from six different AOM sites, SEEP-SRB1a was identified as sulfate-reducing partner in up to 95% of total ANME-2 consortia. SEEP-SRB1a cells exhibited a rod-shaped, vibrioid, or coccoid morphology and were found to be associated with subgroups ANME-2a and ANME-2c. Moreover, SEEP-SRB1a was also detected in 8% to 23% of ANME-3 consortia in Haakon Mosby Mud Volcano sediments, previously described to be predominantly associated with SRB of the Desulfobulbus group. SEEP-SRB1a contributed to only 0.3% to 0.7% of all single cells in almost all samples indicating that these bacteria are highly adapted to a symbiotic relationship with ANME-2. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

  13. Differences in the behavior of 233Pa, 237Np and 239 Pu in bentonite contaminated by sulfate-reducing bacteria

    International Nuclear Information System (INIS)

    Kudo, A.; Fujikawa, Y.; Takigami, H.; Zheng, J.; Asano, H.; Arai, K.; Yoshikawa, H.; Ito, M.

    1998-01-01

    The behaviors of 233 Pa, 237 Np and 239 Pu in high level radioactive wastes from nuclear fuel reprocessing were investigated by a laboratory experiment. Radioactive wastes are glassified and disposed of in geological repositories encased in bentonite as an additional artificial barrier to protect the environment. There is, however, the possibility that some anaerobic bacteria, especially sulfate-reducing bacteria, may flourish within the bentonite during the long disposal period (more than a century). The effects of sulfate-reducing bacteria on the behavior of the radionuclides within bentonite were investigated using the distribution coefficient (Kd) of 233 Pa, 237 Np and 239 Pu. The Kd was obtained with a 0.22 m membrane filter separating radionuclide contents in solid and liquid phases. The anaerobic bacteria, including sulfate-reducing bacteria, used for this investigation originated from the anaerobic treatment of pulp and paper waste and operated for more than one year at Eh around -85 mV. The bentonite used for this study was produced in Japan. The active anaerobic bacteria clearly accumulates considerable amounts of 233 Pa and 239 Pu by producing high Kd values of nearly 100,000, while Kds of 233 Pa and 239 Pu for the sterilized anaerobic bacteria were less than 10,000. In other words, live anaerobic bacteria can hold considerably higher amounts of the radionuclides compared to dead bacteria. Furthermore, high Kd values were obtained for anaerobic bacteria at pH 5-9. In contrast, Kd values for the radionuclide 237 Np were not influenced by the anaerobic bacteria but were controlled by chemical environmental conditions such as like pH. Another comparison was conducted for the radionuclides for mixtures of non-sterilized bacteria with bentonite. (author)

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

    Science.gov (United States)

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

    2012-06-01

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

  15. Thermophilic bacteria in Moroccan hot springs, salt marshes and desert soils.

    Science.gov (United States)

    Aanniz, Tarik; Ouadghiri, Mouna; Melloul, Marouane; Swings, Jean; Elfahime, Elmostafa; Ibijbijen, Jamal; Ismaili, Mohamed; Amar, Mohamed

    2015-06-01

    The diversity of thermophilic bacteria was investigated in four hot springs, three salt marshes and 12 desert sites in Morocco. Two hundred and forty (240) thermophilic bacteria were recovered, identified and characterized. All isolates were Gram positive, rod-shaped, spore forming and halotolerant. Based on BOXA1R-PCR and 16S rRNA gene sequencing, the recovered isolates were dominated by the genus Bacillus (97.5%) represented by B. licheniformis (119), B. aerius (44), B. sonorensis (33), B. subtilis (subsp. spizizenii (2) and subsp. inaquosurum (6)), B. amyloliquefaciens (subsp. amyloliquefaciens (4) and subsp. plantarum (4)), B. tequilensis (3), B. pumilus (3) and Bacillus sp. (19). Only six isolates (2.5%) belonged to the genus Aeribacillus represented by A. pallidus (4) and Aeribacillus sp. (2). In this study, B. aerius and B. tequilensis are described for the first time as thermophilic bacteria. Moreover, 71.25%, 50.41% and 5.41% of total strains exhibited high amylolytic, proteolytic or cellulolytic activity respectively.

  16. Thermophilic bacteria in Moroccan hot springs, salt marshes and desert soils

    Directory of Open Access Journals (Sweden)

    Tarik Aanniz

    2015-06-01

    Full Text Available The diversity of thermophilic bacteria was investigated in four hot springs, three salt marshes and 12 desert sites in Morocco. Two hundred and forty (240 thermophilic bacteria were recovered, identified and characterized. All isolates were Gram positive, rod-shaped, spore forming and halotolerant. Based on BOXA1R-PCR and 16S rRNA gene sequencing, the recovered isolates were dominated by the genus Bacillus (97.5% represented by B. licheniformis (119, B. aerius (44, B. sonorensis (33, B. subtilis (subsp. spizizenii (2 and subsp. inaquosurum (6, B. amyloliquefaciens (subsp. amyloliquefaciens (4 and subsp. plantarum (4, B. tequilensis (3, B. pumilus (3 and Bacillus sp. (19. Only six isolates (2.5% belonged to the genus Aeribacillus represented by A. pallidus (4 and Aeribacillus sp. (2. In this study, B. aerius and B. tequilensis are described for the first time as thermophilic bacteria. Moreover, 71.25%, 50.41% and 5.41% of total strains exhibited high amylolytic, proteolytic or cellulolytic activity respectively.

  17. Thermophilic Biohydrogen Production

    DEFF Research Database (Denmark)

    Karakashev, Dimitar Borisov; Angelidaki, Irini

    2011-01-01

    Dark fermentative hydrogen production at thermophilic conditions is attractive process for biofuel production. From thermodynamic point of view, higher temperatures favor biohydrogen production. Highest hydrogen yields are always associated with acetate, or with mixed acetate- butyrate type...... fermentation. On the contrary the hydrogen yield decreases, with increasing concentrations of lactate, ethanol or propionate. Major factors affecting dark fermentative biohydrogen production are organic loading rate (OLR), pH, hydraulic retention time (HRT), dissolved hydrogen and dissolved carbon dioxide...... concentrations, and soluble metabolic profile (SMP). A number of thermophilic and extreme thermophilic cultures (pure and mixed) have been studied for biohydrogen production from different feedstocks - pure substrates and waste/wastewaters. Variety of process technologies (operational conditions...

  18. Distribution of benthic phototrophs, sulfate reducers, and methanogens in two adjacent saltern evaporation ponds in Eilat, Israel

    Czech Academy of Sciences Publication Activity Database

    Sørensen, K.; Řeháková, Klára; Zapomělová, Eliška; Oren, A.

    2009-01-01

    Roč. 56, 2-3 (2009), s. 275-284 ISSN 0948-3055. [GAP workshop /8./. Eilat, 30.03.2008-08.04.2008] R&D Projects: GA ČR(CZ) GA206/06/0462; GA AV ČR(CZ) KJB600960703; GA AV ČR(CZ) 1QS600170504 Institutional research plan: CEZ:AV0Z60170517; CEZ:AV0Z60050516 Keywords : salterns * microbial community * molecular ecology * phototrohs * sulfate reducers * methanogens Subject RIV: EH - Ecology, Behaviour Impact factor: 1.743, year: 2009

  19. Toward a rigorous network of protein-protein interactions of the model sulfate reducer Desulfovibrio vulgaris Hildenborough

    Energy Technology Data Exchange (ETDEWEB)

    Chhabra, S.R.; Joachimiak, M.P.; Petzold, C.J.; Zane, G.M.; Price, M.N.; Gaucher, S.; Reveco, S.A.; Fok, V.; Johanson, A.R.; Batth, T.S.; Singer, M.; Chandonia, J.M.; Joyner, D.; Hazen, T.C.; Arkin, A.P.; Wall, J.D.; Singh, A.K.; Keasling, J.D.

    2011-05-01

    Protein–protein interactions offer an insight into cellular processes beyond what may be obtained by the quantitative functional genomics tools of proteomics and transcriptomics. The aforementioned tools have been extensively applied to study E. coli and other aerobes and more recently to study the stress response behavior of Desulfovibrio 5 vulgaris Hildenborough, a model anaerobe and sulfate reducer. In this paper we present the first attempt to identify protein-protein interactions in an obligate anaerobic bacterium. We used suicide vector-assisted chromosomal modification of 12 open reading frames encoded by this sulfate reducer to append an eight amino acid affinity tag to the carboxy-terminus of the chosen proteins. Three biological replicates of the 10 ‘pulled-down’ proteins were separated and analyzed using liquid chromatography-mass spectrometry. Replicate agreement ranged between 35% and 69%. An interaction network among 12 bait and 90 prey proteins was reconstructed based on 134 bait-prey interactions computationally identified to be of high confidence. We discuss the biological significance of several unique metabolic features of D. vulgaris revealed by this protein-protein interaction data 15 and protein modifications that were observed. These include the distinct role of the putative carbon monoxide-induced hydrogenase, unique electron transfer routes associated with different oxidoreductases, and the possible role of methylation in regulating sulfate reduction.

  20. Influence of calcareous deposit on corrosion behavior of Q235 carbon steel with sulfate-reducing bacteria

    Science.gov (United States)

    Zhang, Jie; Li, Xiaolong; Wang, Jiangwei; Xu, Weichen; Duan, Jizhou; Chen, Shougang; Hou, Baorong

    2017-12-01

    Cathodic protection is a very effective method to protect metals, which can form calcareous deposits on metal surface. Research on the interrelationship between fouling organism and calcareous deposits is very important but very limited, especially sulfate-reducing bacteria (SRB). SRB is a kind of very important fouling organism that causes microbial corrosion of metals. A study of the influence of calcareous deposit on corrosion behavior of Q235 carbon steel in SRB-containing culture medium was carried out using electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and surface spectroscopy (EDS). The calcareous deposit was formed with good crystallinity and smooth surface under the gradient current density of -30 μA cm-2 in natural seawater for 72 h. Our results can help elucidate the formation of calcareous deposits and reveal the interrelationship between SRB and calcareous deposits under cathodic protection. The results indicate that the corrosion tendency of carbon steel was obviously affected by Sulfate-reducing Bacteria (SRB) metabolic activity and the calcareous deposit formed on the surface of carbon steel under cathodic protection was favourable to reduce the corrosion rate. Calcareous deposits can promote bacterial adhesion before biofilm formation. The results revealed the interaction between biofouling and calcareous deposits, and the anti-corrosion ability was enhanced by a kind of inorganic and organic composite membranes formed by biofilm and calcareous deposits.

  1. Determination of biocorrosion of low alloy steel by sulfate-reducing Desulfotomaculum sp. isolated from crude oil field

    Energy Technology Data Exchange (ETDEWEB)

    Cetin, D.; Doenmez, G. [Faculty of Science, Department of Biology, Ankara University, Tandogan, 06100, Ankara (Turkey); Bilgic, S. [Faculty of Science, Department of Chemistry, Ankara University, Tandogan, 06100, Ankara (Turkey); Doenmez, S. [Faculty of Engineering, Department of Food Engineering, Ankara University, Diskapi, 06110 Ankara (Turkey)

    2007-11-15

    In this study corrosion behavior of low alloy steel, in the presence of anaerobic sulfate-reducing Desulfotomaculum sp. which was isolated from an oil production well, was investigated. In order to determine corrosion rates and mechanisms, mass loss measurements and electrochemical polarization studies were performed without and with bacteria in the culture medium. Scanning electron microscopic observations and energy dispersive X-ray spectra (EDS) analysis were made on steel coupons. The effect of iron concentration on corrosion behavior was determined by Tafel extrapolation method. In a sterile culture medium, as the FeSO{sub 4} . 7H{sub 2}O concentration increased, corrosion potential (E{sub cor}) values shifted towards more anodic potentials and corrosion current density (I{sub cor}) values increased considerably. After inoculation of sulfate-reducing bacteria (SRB), E{sub cor} shifted towards cathodic values. I{sub cor} values increased with increasing incubation time for 10 and 100 mg/L concentrations of FeSO{sub 4} . 7H{sub 2}O. Results have shown that the corrosion activity changed due to several factors such as bacterial metabolites, ferrous sulfide, hydrogen sulfide, iron phosphide, and cathodic depolarization effect. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  2. Microbial Diversity in Sulfate-Reducing Marine Sediment Enrichment Cultures Associated with Anaerobic Biotransformation of Coastal Stockpiled Phosphogypsum (Sfax, Tunisia

    Directory of Open Access Journals (Sweden)

    Hana Zouch

    2017-08-01

    Full Text Available Anaerobic biotechnology using sulfate-reducing bacteria (SRB is a promising alternative for reducing long-term stockpiling of phosphogypsum (PG, an acidic (pH ~3 by-product of the phosphate fertilizer industries containing high amounts of sulfate. The main objective of this study was to evaluate, for the first time, the diversity and ability of anaerobic marine microorganisms to convert sulfate from PG into sulfide, in order to look for marine SRB of biotechnological interest. A series of sulfate-reducing enrichment cultures were performed using different electron donors (i.e., acetate, formate, or lactate and sulfate sources (i.e., sodium sulfate or PG as electron acceptors. Significant sulfide production was observed from enrichment cultures inoculated with marine sediments, collected near the effluent discharge point of a Tunisian fertilizer industry (Sfax, Tunisia. Sulfate sources impacted sulfide production rates from marine sediments as well as the diversity of SRB species belonging to Deltaproteobacteria. When PG was used as sulfate source, Desulfovibrio species dominated microbial communities of marine sediments, while Desulfobacter species were mainly detected using sodium sulfate. Sulfide production was also affected depending on the electron donor used, with the highest production obtained using formate. In contrast, low sulfide production (acetate-containing cultures was associated with an increase in the population of Firmicutes. These results suggested that marine Desulfovibrio species, to be further isolated, are potential candidates for bioremediation of PG by immobilizing metals and metalloids thanks to sulfide production by these SRB.

  3. Enzymes produced by halotolerant spore-forming gram-positive bacterial strains isolated from a resting habitat (Restinga de Jurubatiba) in Rio de Janeiro, Brazil: focus on proteases.

    Science.gov (United States)

    D Santos, Anderson Fragoso; Pacheco, Clarissa Almeida; Valle, Roberta D Santos; Seldin, Lucy; D Santos, André Luis Souza

    2014-12-01

    The screening for hydrolases-producing, halotolerant, and spore-forming gram-positive bacteria from the root, rhizosphere, and non-rhizosphere soil of Blutaparon portulacoides, a plant found in the Restinga de Jurubatiba located at the northern region of Rio de Janeiro State, Brazil, resulted in the isolation of 22 strains. These strains were identified as Halobacillus blutaparonensis (n = 2), Oceanobacillus picturae (n = 5), and Oceanobacillus iheyensis (n = 15), and all showed the ability to produce different extracellular enzymes. A total of 20 isolates (90.9 %) showed activity for protease, 5 (22.7 %) for phytase, 3 (13.6 %) for cellulase, and 2 (9.1 %) for amylase. Some bacterial strains were capable of producing three (13.6 %) or two (9.1 %) distinct hydrolytic enzymes. However, no bacterial strain with ability to produce esterase and DNase was observed. The isolate designated M9, belonging to the species H. blutaparonensis, was the best producer of protease and also yielded amylase and phytase. This strain was chosen for further studies regarding its protease activity. The M9 strain produced similar amounts of protease when grown either without or with different NaCl concentrations (from 0.5 to 10 %). A simple inspection of the cell-free culture supernatant by gelatin-sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed the presence of three major alkaline proteases of 40, 50, and 70 kDa, which were fully inhibited by phenylmethylsulfonyl fluoride (PMSF) and tosyl-L-phenylalanine chloromethyl ketone (TPCK) (two classical serine protease inhibitors). The secreted proteases were detected in a wide range of temperature (from 4 to 45 °C) and their hydrolytic activities were stimulated by NaCl (up to 10 %). The serine proteases produced by the M9 strain cleaved gelatin, casein, albumin, and hemoglobin, however, in different extensions. Collectively, these results suggest the potential use of the M9 strain in biotechnological

  4. Microbial methanogenesis in the sulfate-reducing zone of sediments in the Eckernförde Bay, SW Baltic Sea

    Science.gov (United States)

    Maltby, Johanna; Steinle, Lea; Löscher, Carolin R.; Bange, Hermann W.; Fischer, Martin A.; Schmidt, Mark; Treude, Tina

    2018-01-01

    Benthic microbial methanogenesis is a known source of methane in marine systems. In most sediments, the majority of methanogenesis is located below the sulfate-reducing zone, as sulfate reducers outcompete methanogens for the major substrates hydrogen and acetate. The coexistence of methanogenesis and sulfate reduction has been shown before and is possible through the usage of noncompetitive substrates by methanogens such as methanol or methylated amines. However, knowledge about the magnitude, seasonality, and environmental controls of this noncompetitive methane production is sparse. In the present study, the presence of methanogenesis within the sulfate reduction zone (SRZ methanogenesis) was investigated in sediments (0-30 cm below seafloor, cm b.s.f.) of the seasonally hypoxic Eckernförde Bay in the southwestern Baltic Sea. Water column parameters such as oxygen, temperature, and salinity together with porewater geochemistry and benthic methanogenesis rates were determined in the sampling area Boknis Eck quarterly from March 2013 to September 2014 to investigate the effect of seasonal environmental changes on the rate and distribution of SRZ methanogenesis, to estimate its potential contribution to benthic methane emissions, and to identify the potential methanogenic groups responsible for SRZ methanogenesis. The metabolic pathway of methanogenesis in the presence or absence of sulfate reducers, which after the addition of a noncompetitive substrate was studied in four experimental setups: (1) unaltered sediment batch incubations (net methanogenesis), (2) 14C-bicarbonate labeling experiments (hydrogenotrophic methanogenesis), (3) manipulated experiments with the addition of either molybdate (sulfate reducer inhibitor), 2-bromoethanesulfonate (methanogen inhibitor), or methanol (noncompetitive substrate, potential methanogenesis), and (4) the addition of 13C-labeled methanol (potential methylotrophic methanogenesis). After incubation with methanol, molecular

  5. Microbial methanogenesis in the sulfate-reducing zone of sediments in the Eckernförde Bay, SW Baltic Sea

    Directory of Open Access Journals (Sweden)

    J. Maltby

    2018-01-01

    Full Text Available Benthic microbial methanogenesis is a known source of methane in marine systems. In most sediments, the majority of methanogenesis is located below the sulfate-reducing zone, as sulfate reducers outcompete methanogens for the major substrates hydrogen and acetate. The coexistence of methanogenesis and sulfate reduction has been shown before and is possible through the usage of noncompetitive substrates by methanogens such as methanol or methylated amines. However, knowledge about the magnitude, seasonality, and environmental controls of this noncompetitive methane production is sparse. In the present study, the presence of methanogenesis within the sulfate reduction zone (SRZ methanogenesis was investigated in sediments (0–30 cm below seafloor, cm b.s.f. of the seasonally hypoxic Eckernförde Bay in the southwestern Baltic Sea. Water column parameters such as oxygen, temperature, and salinity together with porewater geochemistry and benthic methanogenesis rates were determined in the sampling area Boknis Eck quarterly from March 2013 to September 2014 to investigate the effect of seasonal environmental changes on the rate and distribution of SRZ methanogenesis, to estimate its potential contribution to benthic methane emissions, and to identify the potential methanogenic groups responsible for SRZ methanogenesis. The metabolic pathway of methanogenesis in the presence or absence of sulfate reducers, which after the addition of a noncompetitive substrate was studied in four experimental setups: (1 unaltered sediment batch incubations (net methanogenesis, (2 14C-bicarbonate labeling experiments (hydrogenotrophic methanogenesis, (3 manipulated experiments with the addition of either molybdate (sulfate reducer inhibitor, 2-bromoethanesulfonate (methanogen inhibitor, or methanol (noncompetitive substrate, potential methanogenesis, and (4 the addition of 13C-labeled methanol (potential methylotrophic methanogenesis. After incubation with

  6. Thermophilic microorganisms in biomining.

    Science.gov (United States)

    Donati, Edgardo Rubén; Castro, Camila; Urbieta, María Sofía

    2016-11-01

    Biomining is an applied biotechnology for mineral processing and metal extraction from ores and concentrates. This alternative technology for recovering metals involves the hydrometallurgical processes known as bioleaching and biooxidation where the metal is directly solubilized or released from the matrix for further solubilization, respectively. Several commercial applications of biomining can be found around the world to recover mainly copper and gold but also other metals; most of them are operating at temperatures below 40-50 °C using mesophilic and moderate thermophilic microorganisms. Although biomining offers an economically viable and cleaner option, its share of the world´s production of metals has not grown as much as it was expected, mainly considering that due to environmental restrictions in many countries smelting and roasting technologies are being eliminated. The slow rate of biomining processes is for sure the main reason of their poor implementation. In this scenario the use of thermophiles could be advantageous because higher operational temperature would increase the rate of the process and in addition it would eliminate the energy input for cooling the system (bioleaching reactions are exothermic causing a serious temperature increase in bioreactors and inside heaps that adversely affects most of the mesophilic microorganisms) and it would decrease the passivation of mineral surfaces. In the last few years many thermophilic bacteria and archaea have been isolated, characterized, and even used for extracting metals. This paper reviews the current status of biomining using thermophiles, describes the main characteristics of thermophilic biominers and discusses the future for this biotechnology.

  7. Thermophilic archaea activate butane via alkyl-coenzyme M formation.

    Science.gov (United States)

    Laso-Pérez, Rafael; Wegener, Gunter; Knittel, Katrin; Widdel, Friedrich; Harding, Katie J; Krukenberg, Viola; Meier, Dimitri V; Richter, Michael; Tegetmeyer, Halina E; Riedel, Dietmar; Richnow, Hans-Hermann; Adrian, Lorenz; Reemtsma, Thorsten; Lechtenfeld, Oliver J; Musat, Florin

    2016-11-17

    The anaerobic formation and oxidation of methane involve unique enzymatic mechanisms and cofactors, all of which are believed to be specific for C 1 -compounds. Here we show that an anaerobic thermophilic enrichment culture composed of dense consortia of archaea and bacteria apparently uses partly similar pathways to oxidize the C 4 hydrocarbon butane. The archaea, proposed genus 'Candidatus Syntrophoarchaeum', show the characteristic autofluorescence of methanogens, and contain highly expressed genes encoding enzymes similar to methyl-coenzyme M reductase. We detect butyl-coenzyme M, indicating archaeal butane activation analogous to the first step in anaerobic methane oxidation. In addition, Ca. Syntrophoarchaeum expresses the genes encoding β-oxidation enzymes, carbon monoxide dehydrogenase and reversible C 1 methanogenesis enzymes. This allows for the complete oxidation of butane. Reducing equivalents are seemingly channelled to HotSeep-1, a thermophilic sulfate-reducing partner bacterium known from the anaerobic oxidation of methane. Genes encoding 16S rRNA and methyl-coenzyme M reductase similar to those identifying Ca. Syntrophoarchaeum were repeatedly retrieved from marine subsurface sediments, suggesting that the presented activation mechanism is naturally widespread in the anaerobic oxidation of short-chain hydrocarbons.

  8. Phylogenomic re-assessment of the thermophilic genus Geobacillus.

    Science.gov (United States)

    Aliyu, Habibu; Lebre, Pedro; Blom, Jochen; Cowan, Don; De Maayer, Pieter

    2016-12-01

    Geobacillus is a genus of Gram-positive, aerobic, spore-forming obligate thermophiles. The descriptions and subsequent affiliations of the species in the genus have mostly been based on polyphasic taxonomy rules that include traditional sequence-based methods such as DNA-DNA hybridization and comparison of 16S rRNA gene sequences. Currently, there are fifteen validly described species within the genus. The availability of whole genome sequences has provided an opportunity to validate and/or re-assess these conventional estimates of genome relatedness. We have applied whole genome approaches to estimate the phylogenetic relatedness among the sixty-three Geobacillus strains for which genome sequences are currently publicly available, including the type strains of eleven validly described species. The phylogenomic metrics AAI (Average Amino acid Identity), ANI (Average Nucleotide Identity) and dDDH (digital DNA-DNA hybridization) indicated that the current genus Geobacillus is comprised of sixteen distinct genomospecies, including several potentially novel species. Furthermore, a phylogeny constructed on the basis of the core genes identified from the whole genome analyses indicated that the genus clusters into two monophyletic clades that clearly differ in terms of nucleotide base composition. The G+C content ranges for clade I and II were 48.8-53.1% and 42.1-44.4%, respectively. We therefore suggest that the Geobacillus species currently residing within clade II be considered as a new genus. Copyright © 2016 Elsevier GmbH. All rights reserved.

  9. Dispersal of thermophilic Desulfotomaculum endospores into Baltic Sea sediments over thousands of years.

    Science.gov (United States)

    de Rezende, Júlia Rosa; Kjeldsen, Kasper Urup; Hubert, Casey R J; Finster, Kai; Loy, Alexander; Jørgensen, Bo Barker

    2013-01-01

    Patterns of microbial biogeography result from a combination of dispersal, speciation and extinction, yet individual contributions exerted by each of these mechanisms are difficult to isolate and distinguish. The influx of endospores of thermophilic microorganisms to cold marine sediments offers a natural model for investigating passive dispersal in the ocean. We investigated the activity, diversity and abundance of thermophilic endospore-forming sulfate-reducing bacteria (SRB) in Aarhus Bay by incubating pasteurized sediment between 28 and 85 °C, and by subsequent molecular diversity analyses of 16S rRNA and of the dissimilatory (bi)sulfite reductase (dsrAB) genes within the endospore-forming SRB genus Desulfotomaculum. The thermophilic Desulfotomaculum community in Aarhus Bay sediments consisted of at least 23 species-level 16S rRNA sequence phylotypes. In two cases, pairs of identical 16S rRNA and dsrAB sequences in Arctic surface sediment 3000 km away showed that the same phylotypes are present in both locations. Radiotracer-enhanced most probable number analysis revealed that the abundance of endospores of thermophilic SRB in Aarhus Bay sediment was ca. 10(4) per cm(3) at the surface and decreased exponentially to 10(0) per cm(3) at 6.5 m depth, corresponding to 4500 years of sediment age. Thus, a half-life of ca. 300 years was estimated for the thermophilic SRB endospores deposited in Aarhus Bay sediments. These endospores were similarly detected in the overlying water column, indicative of passive dispersal in water masses preceding sedimentation. The sources of these thermophiles remain enigmatic, but at least one source may be common to both Aarhus Bay and Arctic sediments.

  10. A mathematical model for the interactive behavior of sulfate-reducing bacteria and methanogens during anaerobic digestion.

    Science.gov (United States)

    Ahammad, S Ziauddin; Gomes, James; Sreekrishnan, T R

    2011-09-01

    Anaerobic degradation of waste involves different classes of microorganisms, and there are different types of interactions among them for substrates, terminal electron acceptors, and so on. A mathematical model is developed based on the mass balance of different substrates, products, and microbes present in the system to study the interaction between methanogens and sulfate-reducing bacteria (SRB). The performance of major microbial consortia present in the system, such as propionate-utilizing acetogens, butyrate-utilizing acetogens, acetoclastic methanogens, hydrogen-utilizing methanogens, and SRB were considered and analyzed in the model. Different substrates consumed and products formed during the process also were considered in the model. The experimental observations and model predictions showed very good prediction capabilities of the model. Model prediction was validated statistically. It was observed that the model-predicted values matched the experimental data very closely, with an average error of 3.9%.

  11. BIOREMEDIATION FOR ACID MINE DRAINAGE: ORGANIC SOLID WASTE AS CARBON SOURCES FOR SULFATE-REDUCING BACTERIA: A REVIEW

    Directory of Open Access Journals (Sweden)

    I. N. Jamil

    2013-12-01

    Full Text Available Biological sulfate reduction has been slowly replacing chemical unit processes to treat acid mine drainage (AMD. Bioremediations for AMD treatment are favored due to their low capital and maintenance cost. This paper describes the available AMD treatment, current SRB commercialization such as THIOPAQ® and BioSulphide® technologies, and also the factors and limitations faced. THIOPAQ® and BioSulphide® technologies use expensive carbon sources such as hydrogen as the electron donor. This paper discusses the possibility of organic solid waste as an alternative substrate as it is cheaper and abundant. A possible AMD treatment system setup was also proposed to test the efficiency of sulfate-reducing bacteria utilizing organic solid substrate.

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

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  13. Bio-Reduction of Graphene Oxide Using Sulfate-Reducing Bacteria and Its Implication on Anti-Biocorrosion.

    Science.gov (United States)

    Song, Tian-Shun; Tan, Wei-Min; Xie, Jingjing

    2018-08-01

    In this paper, we developed an environmental friendly, cost effective, simple and green approach to reduce graphene oxide (GO) by a sulfate-reducing bacterium Desulfovibrio desulfuricans. The D. desulfuricans reduces exfoliated GO to reduced graphene oxide (rGO) at 25 °C in an aqueous solution without any toxic and environmentally harmful reducing agents. The rGO was characterized with X-ray Diffraction, Fourier Transform Infrared Spectroscopy, Scanning Electron Microscopy, Transmission Electron Microscope, X-ray Photoelectron Spectroscopy and Raman Spectroscopy. The analysis results showed that rGO had excellent properties and multi-layer graphene sheets structure. Furthermore, we demonstrated that D. desulfuricans, one of the primary bacteria responsible for the biocorrosion of various metals, might reduce GO to rGO on the surface of copper and prevented the corrosion of copper, which confirmed that electrophoretic deposition of GO on the surface of metals had great potential on the anti-biocorrosion applications.

  14. Community structure, cellular rRNA content, and activity of sulfate-reducing bacteria in marine Arctic sediments

    DEFF Research Database (Denmark)

    Ravenschlag, K.; Sahm, K.; Knoblauch, C.

    2000-01-01

    The community structure of sulfate-reducing bacteria (SRB) of a marine Arctic sediment (Smeerenburg-fjorden, Svalbard) a-as characterized by both fluorescence in situ hybridization (FISH) and rRNA slot blot hybridization by using group- and genus-specific 16S rRNA-targeted oligonucleotide probes...... that FISH and rRNA slot blot hybridization gave comparable results. Furthermore, a combination of the two methods allowed us to calculate specific cellular rRNA contents with respect to localization in the sediment profile. The rRNA contents of Desulfosarcina-Desulfococcus cells were highest in the first 5...... mm of the sediment (0.9 and 1.4 fg, respectively) and decreased steeply with depth, indicating that maximal metabolic activity occurred close to the surface, Based on SRB cell numbers, cellular sulfate reduction rates were calculated. The rates were highest in the surface layer (0.14 fmol cell(-1...

  15. Quorum Sensing and the Use of Quorum Quenchers as Natural Biocides to Inhibit Sulfate-Reducing Bacteria

    Directory of Open Access Journals (Sweden)

    Giantommaso Scarascia

    2016-12-01

    Full Text Available Sulfate-reducing bacteria (SRB are one of the main protagonist groups of biocorrosion in the seawater environment. Given their principal role in biocorrosion, it remains a crucial task to develop strategies to reduce the abundance of SRBs. Conventional approaches include the use of biocides and antibiotics, which can impose health, safety, and environmental concerns. This review examines an alternative approach to this problem. This is achieved by reviewing the role of quorum sensing (QS in SRB populations and its impact on the biofilm formation process. Genome databases of SRBs are mined to look for putative QS systems and homologous protein sequences representative of autoinducer receptors or synthases. Subsequently, this review puts forward the potential use of quorum quenchers as natural biocides against SRBs and outlines the potential strategies for the implementation of this approach.

  16. Quorum Sensing and the Use of Quorum Quenchers as Natural Biocides to Inhibit Sulfate-Reducing Bacteria

    KAUST Repository

    Scarascia, Giantommaso; Wang, Tiannyu; Hong, Pei-Ying

    2016-01-01

    Sulfate-reducing bacteria (SRB) are one of the main protagonist groups of biocorrosion in the seawater environment. Given their principal role in biocorrosion, it remains a crucial task to develop strategies to reduce the abundance of SRBs. Conventional approaches include the use of biocides and antibiotics, which can impose health, safety, and environmental concerns. This review examines an alternative approach to this problem. This is achieved by reviewing the role of quorum sensing (QS) in SRB populations and its impact on the biofilm formation process. Genome databases of SRBs are mined to look for putative QS systems and homologous protein sequences representative of autoinducer receptors or synthases. Subsequently, this review puts forward the potential use of quorum quenchers as natural biocides against SRBs and outlines the potential strategies for the implementation of this approach.

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

    Science.gov (United States)

    Dev, Subhabrata; Roy, Shantonu; Bhattacharya, Jayanta

    2016-07-15

    A novel marine waste extract (MWE) as alternative nitrogen source was explored for the growth of sulfate reducing bacteria (SRB). Variation of sulfate and nitrogen (MWE) showed that SRB growth follows an uncompetitive inhibition model. The maximum specific growth rates (μmax) of 0.085 and 0.124 h(-1) and inhibition constants (Ki) of 56 and 4.6 g/L were observed under optimized sulfate and MWE concentrations, respectively. The kinetic data shows that MWE improves the microbial growth by 27%. The packed bed bioreactor (PBR) under optimized sulfate and MWE regime showed sulfate removal efficiency of 62-66% and metals removal efficiency of 66-75% on using mine wastewater. The microbial community analysis using DGGE showed dominance of SRB (87-89%). The study indicated the optimum dosing of sulfate and cheap organic nitrogen to promote the growth of SRB over other bacteria. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Quorum Sensing and the Use of Quorum Quenchers as Natural Biocides to Inhibit Sulfate-Reducing Bacteria

    KAUST Repository

    Scarascia, Giantommaso

    2016-12-15

    Sulfate-reducing bacteria (SRB) are one of the main protagonist groups of biocorrosion in the seawater environment. Given their principal role in biocorrosion, it remains a crucial task to develop strategies to reduce the abundance of SRBs. Conventional approaches include the use of biocides and antibiotics, which can impose health, safety, and environmental concerns. This review examines an alternative approach to this problem. This is achieved by reviewing the role of quorum sensing (QS) in SRB populations and its impact on the biofilm formation process. Genome databases of SRBs are mined to look for putative QS systems and homologous protein sequences representative of autoinducer receptors or synthases. Subsequently, this review puts forward the potential use of quorum quenchers as natural biocides against SRBs and outlines the potential strategies for the implementation of this approach.

  19. Thermophilic anaerobic oxidation of methane by marine microbial consortia.

    Science.gov (United States)

    Holler, Thomas; Widdel, Friedrich; Knittel, Katrin; Amann, Rudolf; Kellermann, Matthias Y; Hinrichs, Kai-Uwe; Teske, Andreas; Boetius, Antje; Wegener, Gunter

    2011-12-01

    The anaerobic oxidation of methane (AOM) with sulfate controls the emission of the greenhouse gas methane from the ocean floor. AOM is performed by microbial consortia of archaea (ANME) associated with partners related to sulfate-reducing bacteria. In vitro enrichments of AOM were so far only successful at temperatures ≤25 °C; however, energy gain for growth by AOM with sulfate is in principle also possible at higher temperatures. Sequences of 16S rRNA genes and core lipids characteristic for ANME as well as hints of in situ AOM activity were indeed reported for geothermally heated marine environments, yet no direct evidence for thermophilic growth of marine ANME consortia was obtained to date. To study possible thermophilic AOM, we investigated hydrothermally influenced sediment from the Guaymas Basin. In vitro incubations showed activity of sulfate-dependent methane oxidation between 5 and 70 °C with an apparent optimum between 45 and 60 °C. AOM was absent at temperatures ≥75 °C. Long-term enrichment of AOM was fastest at 50 °C, yielding a 13-fold increase of methane-dependent sulfate reduction within 250 days, equivalent to an apparent doubling time of 68 days. The enrichments were dominated by novel ANME-1 consortia, mostly associated with bacterial partners of the deltaproteobacterial HotSeep-1 cluster, a deeply branching phylogenetic group previously found in a butane-amended 60 °C-enrichment culture of Guaymas sediments. The closest relatives (Desulfurella spp.; Hippea maritima) are moderately thermophilic sulfur reducers. Results indicate that AOM and ANME archaea could be of biogeochemical relevance not only in cold to moderate but also in hot marine habitats.

  20. Influence of sulfate-reducing bacteria on the corrosion of steel in seawater: laboratory and in situ study

    International Nuclear Information System (INIS)

    Benbouzid-Rollet, N.

    1993-01-01

    A fouling reactor was designed to study, the influence of a mixed bio-film on AISI 316 L stainless steel. The bio-film was formed on the steel surface by the fermentative bacterium Vibrio natriegens. The sulfate-reducing bacterium Desulfovibrio vulgaris was then introduced in the reactor and colonized the surface, constituting approximately 5 % of the total population. The settlement of an anaerobic bacterium in the bio-film shows in it the existence of anaerobic micro-niches. Stainless steel electrochemical behavior was analyzed using open circuit potential and potentiodynamic polarization curves. Growth of the bio-film does not induce corrosion, but seems to change the cathodic oxygen reduction kinetics, diminishing the corrosion hazard. This effect increases when D. vulgaris grows in the bio-film. An ennobling of the open circuit potential was observed, similar to field cases already described. A case of drilling corrosion of carbon steel in a harbour area showed the characteristics of anaerobic corrosion related to sulfate-reducing bacteria. The total cultivatable SRB population was quantified and metabolic types were enumerated using specific electron donors. A maximum cell density of 1,1 x 10 8 cells/ cm 2 was estimated, revealing a very important growth of SRB on surfaces. Population structure was different in corroded and non-corroded areas. In corroded area, SRB utilizing benzoate and propionate were more abundant. A strain belonging to the sporulating genus Desulfotomaculum was isolated using these substrates, suggesting a partial aeration in the area of hole appearance. However, in vitro corrosion assays showed that the bacterial population sampled in this area induced a consequent weight loss of steel coupons, in the absence of oxygen. This was observed only with a diversified population, similar to that present in situ. It could not be reproduced with a mixed culture of two purified strains. (author)

  1. ENDOSPORES OF THERMOPHILIC FERMENTATIVE BACTERIA

    DEFF Research Database (Denmark)

    Volpi, Marta

    2016-01-01

    solely based on endospores of sulphate-reducing bacteria (SRB), which presumably constitute only a small fraction of the total thermophilic endospore community reaching cold environments. My PhD project developed an experimental framework for using thermophilic fermentative endospores (TFEs) to trace...

  2. Hydrogen Production by Thermophilic Fermentation

    NARCIS (Netherlands)

    Niel, van E.W.J.; Willquist, K.; Zeidan, A.A.; Vrije, de T.; Mars, A.E.; Claassen, P.A.M.

    2012-01-01

    Of the many ways hydrogen can be produced, this chapter focuses on biological hydrogen production by thermophilic bacteria and archaea in dark fermentations. The thermophiles are held as promising candidates for a cost-effective fermentation process, because of their relatively high yields and broad

  3. Isolation and characterization of two novel ethanol-tolerant facultative-anaerobic thermophilic bacteria strains from waste compost.

    Science.gov (United States)

    Fong, Jiunn C N; Svenson, Charles J; Nakasugi, Kenlee; Leong, Caine T C; Bowman, John P; Chen, Betty; Glenn, Dianne R; Neilan, Brett A; Rogers, Peter L

    2006-10-01

    In a search for potential ethanologens, waste compost was screened for ethanol-tolerant thermophilic microorganisms. Two thermophilic bacterial strains, M5EXG and M10EXG, with tolerance of 5 and 10% (v/v) ethanol, respectively, were isolated. Both isolates are facultative anaerobic, non-spore forming, non-motile, catalase-positive, oxidase-negative, Gram-negative rods that are capable of utilizing a range of carbon sources including arabinose, galactose, mannose, glucose and xylose and produce low amounts of ethanol, acetate and lactate. Growth of both isolates was observed in fully defined minimal media within the temperature range 50-80 degrees C and pH 6.0-8.0. Phylogenetic analysis of the 16S rDNA sequences revealed that both isolates clustered with members of subgroup 5 of the genus Bacillus. G+C contents and DNA-DNA relatedness of M5EXG and M10EXG revealed that they are strains belonging to Geobacillus thermoglucosidasius. However, physiological and biochemical differences were evident when isolates M5EXG and M10EXG were compared with G. thermoglucosidasius type strain (DSM 2542(T)). The new thermophilic, ethanol-tolerant strains of G. thermoglucosidasius may be candidates for ethanol production at elevated temperatures.

  4. Production and properties of two novel exopolysaccharides synthesized by a thermophilic bacterium Aeribacillus pallidus 418.

    Science.gov (United States)

    Radchenkova, Nadja; Vassilev, Spasen; Panchev, Ivan; Anzelmo, Gianluca; Tomova, Iva; Nicolaus, Barbara; Kuncheva, Margarita; Petrov, Kaloyan; Kambourova, Margarita

    2013-09-01

    Synthesis of innovative exocellular polysaccharides (EPSs) was reported for few thermophilic microorganisms as one of the mechanisms for surviving at high temperature. Thermophilic aerobic spore-forming bacteria able to produce exopolysaccharides were isolated from hydrothermal springs in Bulgaria. They were referred to four species, such as Aeribacillus pallidus, Geobacillus toebii, Brevibacillus thermoruber, and Anoxybacillus kestanbolensis. The highest production was established for the strain 418, whose phylogenetic and phenotypic properties referred it to the species A. pallidus. Maltose and NH4Cl were observed to be correspondingly the best carbon and nitrogen sources and production yield was increased more than twofold in the process of culture condition optimization. After purification of the polymer fraction, a presence of two different EPSs, electroneutral EPS 1 and negatively charged EPS 2, in a relative weight ratio 3:2.2 was established. They were heteropolysaccharides consisting of unusual high variety of sugars (six for EPS 1 and seven for EPS 2). Six of the sugars were common for both EPSs. The main sugar in EPS 1 was mannose (69.3 %); smaller quantities of glucose (11.2 %), galactosamine (6.3 %), glucosamine (5.4 %), galactose (4.7 %), and ribose (2.9 %) were also identified. The main sugar in EPS 2 was also mannose (33.9 %), followed by galactose (17.9 %), glucose (15.5 %), galactosamine (11.7 %), glucosamine (8.1 %), ribose (5.3 %), and arabinose (4.9 %). Both polymers showed high molecular weight and high thermostability.

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

    Science.gov (United States)

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

    2000-01-01

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

  6. Growth Inhibition of Sulfate-Reducing Bacteria in Produced Water from the Petroleum Industry Using Essential Oils.

    Science.gov (United States)

    Souza, Pamella Macedo de; Goulart, Fátima Regina de Vasconcelos; Marques, Joana Montezano; Bizzo, Humberto Ribeiro; Blank, Arie Fitzgerald; Groposo, Claudia; Sousa, Maíra Paula de; Vólaro, Vanessa; Alviano, Celuta Sales; Moreno, Daniela Sales Alviano; Seldin, Lucy

    2017-04-19

    Strategies for the control of sulfate-reducing bacteria (SRB) in the oil industry involve the use of high concentrations of biocides, but these may induce bacterial resistance and/or be harmful to public health and the environment. Essential oils (EO) produced by plants inhibit the growth of different microorganisms and are a possible alternative for controlling SRB. We aimed to characterize the bacterial community of produced water obtained from a Brazilian petroleum facility using molecular methods, as well as to evaluate the antimicrobial activity of EO from different plants and their major components against Desulfovibrio alaskensis NCIMB 13491 and against SRB growth directly in the produced water. Denaturing gradient gel electrophoresis revealed the presence of the genera Pelobacter and Marinobacterium , Geotoga petraea , and the SRB Desulfoplanes formicivorans in our produced water samples. Sequencing of dsrA insert-containing clones confirmed the presence of sequences related to D. formicivorans . EO obtained from Citrus aurantifolia , Lippia alba LA44 and Cymbopogon citratus , as well as citral, linalool, eugenol and geraniol, greatly inhibited (minimum inhibitory concentration (MIC) = 78 µg/mL) the growth of D. alaskensis in a liquid medium. The same MIC was obtained directly in the produced water with EO from L. alba LA44 (containing 82% citral) and with pure citral. These findings may help to control detrimental bacteria in the oil industry.

  7. Microbial Corrosion of API 5L X-70 Carbon Steel by ATCC 7757 and Consortium of Sulfate-Reducing Bacteria

    Directory of Open Access Journals (Sweden)

    Arman Abdullah

    2014-01-01

    Full Text Available Various cases of accidents involving microbiology influenced corrosion (MIC were reported by the oil and gas industry. Sulfate reducing bacteria (SRB have always been linked to MIC mechanisms as one of the major causes of localized corrosion problems. In this study, SRB colonies were isolated from the soil in suspected areas near the natural gas transmission pipeline in Malaysia. The effects of ATCC 7757 and consortium of isolated SRB upon corrosion on API 5L X-70 carbon steel coupon were investigated using a weight loss method, an open circuit potential method (OCP, and a potentiodynamic polarization curves method in anaerobic conditions. Scanning electron microscopy (SEM and energy dispersive X-ray spectroscopy (EDS were then used to determine the corrosion morphology in verifying the SRB activity and corrosion products formation. Results from the study show that the corrosion rate (CR of weight loss method for the isolated SRB is recorded as 0.2017 mm/yr compared to 0.2530 mm/yr for ATCC 7757. The Tafel plot recorded the corrosion rate of 0.3290 mm/yr for Sg. Ular SRB and 0.2500 mm/yr for Desulfovibrio vulgaris. The results showed that the consortia of isolated SRB were of comparable effects and features with the single ATCC 7757 strain.

  8. TEM investigation of U6+ and Re7+ reduction by Desulfovibrio desulfuricans, a sulfate-reducing bacterium

    International Nuclear Information System (INIS)

    XU, HUIFANG; BARTON, LARRY L.; CHOUDHURY, KEKA; ZHANG, PENGCHU; WANG, YIFENG

    2000-01-01

    Uranium and its fission product Tc in aerobic environment will be in the forms of UO 2 2+ and TcO 4 - . Reduced forms of tetravalent U and Tc are sparingly soluble. As determined by transmission electron microscopy, the reduction of uranyl acetate by immobilized cells of Desulfovibrio desulfuricans results in the production of black uraninite nanocrystals precipitated outside the cell. Some nanocrystals are associated with outer membranes of the cell as revealed from cross sections of these metabolic active sulfate-reducing bacteria. The nanocrystals have an average diameter of 5 nm and have anhedral shape. The reduction of Re 7+ by cells of Desulfovibrio desulfuricans is fast in media containing H 2 an electron donor, and slow in media containing lactic acid. It is proposed that the cytochrome in these cells has an important role in the reduction of uranyl and Re 7+ is (a chemical analogue for Tc 7+ ) through transferring an electron from molecular hydrogen or lactic acid to the oxyions of UO 2 2+ and TcO 4 -

  9. Growth Inhibition of Sulfate-Reducing Bacteria in Produced Water from the Petroleum Industry Using Essential Oils

    Directory of Open Access Journals (Sweden)

    Pamella Macedo de Souza

    2017-04-01

    Full Text Available Strategies for the control of sulfate-reducing bacteria (SRB in the oil industry involve the use of high concentrations of biocides, but these may induce bacterial resistance and/or be harmful to public health and the environment. Essential oils (EO produced by plants inhibit the growth of different microorganisms and are a possible alternative for controlling SRB. We aimed to characterize the bacterial community of produced water obtained from a Brazilian petroleum facility using molecular methods, as well as to evaluate the antimicrobial activity of EO from different plants and their major components against Desulfovibrio alaskensis NCIMB 13491 and against SRB growth directly in the produced water. Denaturing gradient gel electrophoresis revealed the presence of the genera Pelobacter and Marinobacterium, Geotoga petraea, and the SRB Desulfoplanes formicivorans in our produced water samples. Sequencing of dsrA insert-containing clones confirmed the presence of sequences related to D. formicivorans. EO obtained from Citrus aurantifolia, Lippia alba LA44 and Cymbopogon citratus, as well as citral, linalool, eugenol and geraniol, greatly inhibited (minimum inhibitory concentration (MIC = 78 µg/mL the growth of D. alaskensis in a liquid medium. The same MIC was obtained directly in the produced water with EO from L. alba LA44 (containing 82% citral and with pure citral. These findings may help to control detrimental bacteria in the oil industry.

  10. Biologically-induced precipitation of sphalerite-wurtzite nanoparticles by sulfate-reducing bacteria: implications for acid mine drainage treatment.

    Science.gov (United States)

    Castillo, Julio; Pérez-López, Rafael; Caraballo, Manuel A; Nieto, José M; Martins, Mónica; Costa, M Clara; Olías, Manuel; Cerón, Juan C; Tucoulou, Rémi

    2012-04-15

    Several experiments were conducted to evaluate zinc-tolerance of sulfate-reducing bacteria (SRB) obtained from three environmental samples, two inocula from sulfide-mining districts and another inoculum from a wastewater treatment plant. The populations of SRB resisted zinc concentrations of 260 mg/L for 42 days in a sulfate-rich medium. During the experiments, sulfate was reduced to sulfide and concentrations in solution decreased. Zinc concentrations also decreased from 260 mg/L to values below detection limit. Both decreases were consistent with the precipitation of newly-formed sphalerite and wurtzite, two polymorphs of ZnS, forming <2.5-μm-diameter spherical aggregates identified by microscopy and synchrotron-μ-XRD. Sulfate and zinc are present in high concentrations in acid mine drainage (AMD) even after passive treatments based on limestone dissolution. The implementation of a SRB-based zinc removal step in these systems could completely reduce the mobility of all metals, which would improve the quality of stream sediments, water and soils in AMD-affected landscapes. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. Hybrid soliwave technique for mitigating sulfate-reducing bacteria in controlling biocorrosion: a case study on crude oil sample.

    Science.gov (United States)

    Mohd Ali, Muhammad Khairool Fahmy Bin; Abu Bakar, Akrima; Md Noor, Norhazilan; Yahaya, Nordin; Ismail, Mardhiah; Rashid, Ahmad Safuan

    2017-10-01

    Microbiologically influenced corrosion (MIC) is among the common corrosion types for buried and deep-water pipelines that result in costly repair and pipeline failure. Sulfate-reducing bacteria (SRB) are commonly known as the culprit of MIC. The aim of this work is to investigate the performance of combination of ultrasound (US) irradiation and ultraviolet (UV) radiation (known as Hybrid soliwave technique, HyST) at pilot scale to inactivate SRB. The influence of different reaction times with respect to US irradiation and UV radiation and synergistic effect toward SRB consortium was tested and discussed. In this research, the effect of HyST treatment toward SRB extermination and corrosion studies of carbon steel coupon upon SRB activity before and after the treatment were performed using weight loss method. The carbon steel coupons immersed in SRB sample were exposed to HyST treatment at different time of exposure. Additionally, Field Emission Scanning Electron Microscopy coupled with Energy Dispersive X-ray Spectroscopy were used to investigate the corrosion morphology in verifying the end product of SRB activity and corrosion formation after treatment. Results have shown that the US irradiation treatment gives a synergistic effect when combined with UV radiation in mitigating the SRB consortium.

  12. Production of biosurfactant from Bacillus licheniformis for microbial enhanced oil recovery and inhibition the growth of sulfate reducing bacteria

    Directory of Open Access Journals (Sweden)

    H.S. El-Sheshtawy

    2015-06-01

    Full Text Available In this study, the bacterium Bacillus licheniformis has been isolated from oil reservoir; the ability of this bacterium to produce a biosurfactant was detected. Surface properties of the produced biosurfactant were confirmed by determining the emulsification power as well as surface and interfacial tension. The crude biosurfactant has been extracted from supernatant culture growth, and the yield of crude biosurfactant was about 1 g/l. Also, chemical structure of the produced biosurfactant was confirmed using FTIR analysis. Results revealed that, the emulsification power has been increased up to 96% and the surface tension decreased from 72 of distilled water to 36 mN/m after 72 h of incubation. The potential application of this bacterial species in microbial-enhanced oil recovery (MEOR was investigated. The percent of oil recovery was 16.6% upon application in a sand pack column designed to stimulate an oil recovery. It also showed antimicrobial activity against the growth of different strains of SRB (sulfate reducing bacteria. Results revealed that a complete inhibition of SRB growth using 1.0% crude biosurfactant is achieved after 3 h.

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

    Energy Technology Data Exchange (ETDEWEB)

    Winderl, C.; Penning, H.; von Netzer, F.; Meckenstock, R.U.; Lueders, T. [Helmholtz Zentrum Munchen, Neuherberg (Germany)

    2010-10-15

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

  14. Desulfovibrio zosterae sp. nov., a new sulfate reducer isolated from surface-sterilized roots of the seagrass Zostera marina.

    Science.gov (United States)

    Nielsen, J T; Liesack, W; Finster, K

    1999-04-01

    A sulfate-reducing bacterium, designated strain lacT, was isolated from surface-sterilized roots of the benthic macrophyte Zostera marina. Cells were motile by means of a single polar flagellum. Strain lacT utilized lactate, pyruvate, malate, ethanol, L-alanine, fumarate, choline and fructose with sulfate as electron acceptor. In addition, fumarate, pyruvate and fructose were also degraded without an external electron acceptor. Sulfate could be substituted with thiosulfate, sulfite and elemental sulfur. Optimal growth was observed between 32.5 and 34.5 degrees C, at an NaCl concentration of 0.2 M and in a pH range between 6.8 and 7.3. The G + C content of the DNA was 42.7 +/- 0.2 mol%. Desulfoviridin and catalase were present. Strain lacT contained c-type cytochromes. Comparative 16S rRNA gene sequence analysis and the fatty acid pattern grouped this isolate into the genus Desulfovibrio. However, strain lacT differs from all other described Desulfovibrio species on the bases of its 16S rRNA gene sequence, the G + C content, its cellular lipid pattern and the utilization pattern of substrates. These characteristics establish strain lacT (= DSM 11974T) as a novel species of the genus Desulfovibrio, for which the name Desulfovibrio zosterae sp. nov. is proposed.

  15. Unusual Starch Degradation Pathway via Cyclodextrins in the Hyperthermophilic Sulfate-Reducing Archaeon Archaeoglobus fulgidus Strain 7324▿

    Science.gov (United States)

    Labes, Antje; Schönheit, Peter

    2007-01-01

    The hyperthermophilic archaeon Archaeoglobus fulgidus strain 7324 has been shown to grow on starch and sulfate and thus represents the first sulfate reducer able to degrade polymeric sugars. The enzymes involved in starch degradation to glucose 6-phosphate were studied. In extracts of starch-grown cells the activities of the classical starch degradation enzymes, α-amylase and amylopullulanase, could not be detected. Instead, evidence is presented here that A. fulgidus utilizes an unusual pathway of starch degradation involving cyclodextrins as intermediates. The pathway comprises the combined action of an extracellular cyclodextrin glucanotransferase (CGTase) converting starch to cyclodextrins and the intracellular conversion of cyclodextrins to glucose 6-phosphate via cyclodextrinase (CDase), maltodextrin phosphorylase (Mal-P), and phosphoglucomutase (PGM). These enzymes, which are all induced after growth on starch, were characterized. CGTase catalyzed the conversion of starch to mainly β-cyclodextrin. The gene encoding CGTase was cloned and sequenced and showed highest similarity to a glucanotransferase from Thermococcus litoralis. After transport of the cyclodextrins into the cell by a transport system to be defined, these molecules are linearized via a CDase, catalyzing exclusively the ring opening of the cyclodextrins to the respective maltooligodextrins. These are degraded by a Mal-P to glucose 1-phosphate. Finally, PGM catalyzes the conversion of glucose 1-phosphate to glucose 6-phosphate, which is further degraded to pyruvate via the modified Embden-Meyerhof pathway. PMID:17921308

  16. Towards a rigorous network of protein-protein interactions of the model sulfate reducer Desulfovibrio vulgaris Hildenborough.

    Directory of Open Access Journals (Sweden)

    Swapnil R Chhabra

    Full Text Available Protein-protein interactions offer an insight into cellular processes beyond what may be obtained by the quantitative functional genomics tools of proteomics and transcriptomics. The aforementioned tools have been extensively applied to study Escherichia coli and other aerobes and more recently to study the stress response behavior of Desulfovibrio vulgaris Hildenborough, a model obligate anaerobe and sulfate reducer and the subject of this study. Here we carried out affinity purification followed by mass spectrometry to reconstruct an interaction network among 12 chromosomally encoded bait and 90 prey proteins based on 134 bait-prey interactions identified to be of high confidence. Protein-protein interaction data are often plagued by the lack of adequate controls and replication analyses necessary to assess confidence in the results, including identification of potential false positives. We addressed these issues through the use of biological replication, exponentially modified protein abundance indices, results from an experimental negative control, and a statistical test to assign confidence to each putative interacting pair applicable to small interaction data studies. We discuss the biological significance of metabolic features of D. vulgaris revealed by these protein-protein interaction data and the observed protein modifications. These include the distinct role of the putative carbon monoxide-induced hydrogenase, unique electron transfer routes associated with different oxidoreductases, and the possible role of methylation in regulating sulfate reduction.

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

    Science.gov (United States)

    Omil, F; Lens, P; Visser, A; Hulshoff Pol, L W; Lettinga, G

    1998-03-20

    The competition between acetate utilizing methane-producing bacteria (MB) and sulfate-reducing bacteria (SRB) was studied in mesophilic (30 degrees C) upflow anaerobic sludge bed (UASB) reactors (upward velocity 1 m h-1; pH 8) treating volatile fatty acids and sulfate. The UASB reactors treated a VFA mixture (with an acetate:propionate:butyrate ratio of 5:3:2 on COD basis) or acetate as the sole substrate at different COD:sulfate ratios. The outcome of the competition was evaluated in terms of conversion rates and specific methanogenic and sulfidogenic activities. The COD:sulfate ratio was a key factor in the partitioning of acetate utilization between MB and SRB. In excess of sulfate (COD:sulfate ratio lower than 0.67), SRB became predominant over MB after prolonged reactor operation: 250 and 400 days were required to increase the amount of acetate used by SRB from 50 to 90% in the reactor treating, respectively, the VFA mixture or acetate as the sole substrate. The competition for acetate was further studied by dynamic simulations using a mathematical model based on the Monod kinetic parameters of acetate utilizing SRB and MB. The simulations confirmed the long term nature of the competition between these acetotrophs. A high reactor pH (+/-8), a short solid retention time (acetate-utilising SRB to outcompete MB. Copyright 1998 John Wiley & Sons, Inc.

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

    Science.gov (United States)

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

    2013-05-01

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

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

    Science.gov (United States)

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

    2015-12-01

    The influence of Cephalexin (CLX), Tetracycline (TC), Erythromycin (ERY) and Sulfathiazole (ST) on methane-producing archaea (MPA) and sulfate-reducing bacteria (SRB) in anaerobic sludge was investigated using acetate or ethanol as substrate. With antimicrobial concentrations below 400mgL(-1), the relative specific methanogenic activity (SMA) was above 50%, so that the antimicrobials exerted slight effects on archaea. However ERY and ST at 400mgL(-1) caused a 74.5% and 57.6% inhibition to specific sulfidogenic activity (SSA) when the sludge granules were disrupted and ethanol used as substrate. After disruption, microbial tolerance to antimicrobials decreased, but the rate at which MPA utilized acetate and ethanol increased from 0.95gCOD·(gVSS⋅d)(-1) to 1.45gCOD·(gVSS⋅d)(-1) and 0.90gCOD·(gVSS⋅d)(-1) to 1.15gCOD·(gVSS⋅d)(-1) respectively. The ethanol utilization rate for SRB also increased after disruption from 0.35gCOD·(gVSS⋅d)(-1) to 0.46gCOD·(gVSS⋅d)(-1). Removal rates for CLX approaching 20.0% and 25.0% were obtained used acetate and ethanol respectively. The disintegration of granules improved the CLX removal rate to 65% and 78%, but ST was not removed during this process. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  1. Desulfonatronovibrio halophilus sp. nov., a novel moderately halophilic sulfate-reducing bacterium from hypersaline chloride-sulfate lakes in Central Asia

    NARCIS (Netherlands)

    Sorokin, D.Y.; Tourova, T.P.; Abbas, B.; Suhacheva, M.V.; Muyzer, G.

    2012-01-01

    Four strains of lithotrophic sulfate-reducing bacteria (SRB) have been enriched and isolated from anoxic sediments of hypersaline chloride-sulfate lakes in the Kulunda Steppe (Altai, Russia) at 2 M NaCl and pH 7.5. According to the 16S rRNA gene sequence analysis, the isolates were closely related

  2. Desulfonatronovibrio halophilus sp. nov., a novel moderately halophilic sulfate-reducing bacterium from hypersaline chloride–sulfate lakes in Central Asia

    NARCIS (Netherlands)

    Sorokin, D.Y.; Tourova, T.P.; Abbas, B.; Suhacheva, M.V.; Muyzer, G.

    2012-01-01

    Four strains of lithotrophic sulfate-reducing bacteria (SRB) have been enriched and isolated from anoxic sediments of hypersaline chloride–sulfate lakes in the Kulunda Steppe (Altai, Russia) at 2 M NaCl and pH 7.5. According to the 16S rRNA gene sequence analysis, the isolates were closely related

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

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Duu-Jong, E-mail: cedean@mail.ntust.edu.tw [Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan (China); Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan (China); Lee, Chin-Yu [Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan (China); Chang, Jo-Shu [Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan (China); Center for Bioscience and Biotechnology, National Cheng Kung University, Tainan, Taiwan (China); Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan, Taiwan (China)

    2012-12-15

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

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

    Science.gov (United States)

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

    2013-09-01

    Sulfate-reducing bacteria (SRB) participate in microbially induced corrosion (MIC) of equipment and H2S-driven reservoir souring in oil field sites. Successful management of industrial processes requires methods that allow robust monitoring of microbial communities. This study investigated the applicability of denaturing high-performance liquid chromatography (DHPLC) targeting the dissimilatory sulfite reductase ß-subunit (dsrB) gene for monitoring SRB communities in oil field samples from the North Sea, the United States, and Brazil. Fifteen of the 28 screened samples gave a positive result in real-time PCR assays, containing 9 × 10(1) to 6 × 10(5) dsrB gene copies ml(-1). DHPLC and denaturing gradient gel electrophoresis (DGGE) community profiles of the PCR-positive samples shared an overall similarity; both methods revealed the same samples to have the lowest and highest diversity. The SRB communities were diverse, and different dsrB compositions were detected at different geographical locations. The identified dsrB gene sequences belonged to several phylogenetic groups, such as Desulfovibrio, Desulfococcus, Desulfomicrobium, Desulfobulbus, Desulfotignum, Desulfonatronovibrio, and Desulfonauticus. DHPLC showed an advantage over DGGE in that the community profiles were very reproducible from run to run, and the resolved gene fragments could be collected using an automated fraction collector and sequenced without a further purification step. DGGE, on the other hand, included casting of gradient gels, and several rounds of rerunning, excising, and reamplification of bands were needed for successful sequencing. In summary, DHPLC proved to be a suitable tool for routine monitoring of the diversity of SRB communities in oil field samples.

  5. Role of aqueous sulfide and sulfate-reducing bacteria in the kinetics and mechanisms of the reduction of uranyl ion

    International Nuclear Information System (INIS)

    Mohagheghi, A.

    1985-01-01

    Formation of sedimentary rock-hosted uranium ore deposits is thought to have resulted from the reduction by aqueous sulfide species of relatively soluble uranyl ion (U(VI)) to insoluble uranium(IV) oxides and silicates. The origin of this H 2 S in such deposits can be either biogenic or abiogenic. Therefore, the kinetics and mechanism of uranyl ion reduction by aqueous sulfide, and the effect of several key variables on the reduction process in non-bacterial (sterile) systems was studied. The role of both pure and mixed cultures of sulfate-reducing bacteria on the reduction process was also investigated. In sterile systems the reduction reaction generally occurred by a two step reaction sequence. Uranium(V) (as UO 2 + ) and U(IV) (as UO 2 the mineral uraninite) were the intermediate and final products, respectively. The initial concentration of uranyl ion required for reaction initiation had a minimum value of 0.8 ppm at pH 7, and was higher at pH values less than or greater than 7. An induction period was observed in all experiments. No reduction was observed after 8 hours at pH 8. Although increasing ionic strength increased the length of the induction period, it also increased the rate of the reduction of UO 2 + in the second step. No reaction was observed under any experimental conditions with initial UO 2 2+ concentration less than 0.1 ppm, which is thought to be typical for ore forming solutions. However, by absorbing uranyl ion onto kaolinite, the reduction by H 2 S occurred at lower UO 2 2+ concentrations (∼ 0.1 ppm) in that in the homogeneous system. Thus, adsorption may play a significant role in the reduction and therefore in the formation of ore deposits

  6. Enhanced biological stabilization of heavy metals in sediment using immobilized sulfate reducing bacteria beads with inner cohesive nutrient

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xin, E-mail: hgxlixin@hnu.edu.cn [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Dai, Lihua; Zhang, Chang; Zeng, Guangming; Liu, Yunguo [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China); Zhou, Chen [Swette Center for Environmental Biotechnology, Biodesign Institute, Arizona State University (United States); Xu, Weihua; Wu, Youe; Tang, Xinquan; Liu, Wei; Lan, Shiming [College of Environmental Science and Engineering, Hunan University, Changsha 410082 (China); Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082 (China)

    2017-02-15

    Highlights: • Nutrient beads of immobilized SRB were more effective in transforming heavy metals into the more stable bound phases. • Inner cohesive nutrient effectively promoted the stabilization process of heavy metals. • The excellent removal efficiencies of Cu, Zn, Pb and Cd were 76.3%, 95.6%, 100% and 91.2%, respectively. • Easy to recycle and avoid secondary pollution. - Abstract: A series of experiments were conducted for treating heavy metals contaminated sediments sampled from Xiangjiang River, which combined polyvinyl alcohol (PVA) and immobilized sulfate reducing bacteria (SRB) into beads. The sodium lactate was served as the inner cohesive nutrient. Coupling the activity of the SRB with PVA, along with the porous structure and huge specific surface area, provided a convenient channel for the transmission of matter and protected the cells against the toxicity of metals. This paper systematically investigated the stability of Cu, Zn, Pb and Cd and its mechanisms. The results revealed the performance of leaching toxicity was lower and the removal efficiencies of Cu, Zn, Pb and Cd were 76.3%, 95.6%, 100% and 91.2%, respectively. Recycling experiments showed the beads could be reused 5 times with superbly efficiency. These results were also confirmed by continuous extraction at the optimal conditions. Furthermore, X-ray diffraction (XRD) and energy-dispersive spectra (EDS) analysis indicated the heavy metals could be transformed into stable crystal texture. The stabilization of heavy metals was attributed to the carbonyl and acyl amino groups. Results presented that immobilized bacteria with inner nutrient were potentially and practically applied to multi-heavy-metal-contamination sediment.

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

    Directory of Open Access Journals (Sweden)

    Jemaneh eZeleke

    2013-08-01

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

  8. Microbial reduction of structural iron in interstratified illite-smectite minerals by a sulfate-reducing bacterium.

    Science.gov (United States)

    Liu, D; Dong, H; Bishop, M E; Zhang, J; Wang, H; Xie, S; Wang, S; Huang, L; Eberl, D D

    2012-03-01

    Clay minerals are ubiquitous in soils, sediments, and sedimentary rocks and could coexist with sulfate-reducing bacteria (SRB) in anoxic environments, however, the interactions of clay minerals and SRB are not well understood. The objective of this study was to understand the reduction rate and capacity of structural Fe(III) in dioctahedral clay minerals by a mesophilic SRB, Desulfovibrio vulgaris and the potential role in catalyzing smectite illitization. Bioreduction experiments were performed in batch systems, where four different clay minerals (nontronite NAu-2, mixed-layer illite-smectite RAr-1 and ISCz-1, and illite IMt-1) were exposed to D. vulgaris in a non-growth medium with and without anthraquinone-2,6-disulfonate (AQDS) and sulfate. Our results demonstrated that D. vulgaris was able to reduce structural Fe(III) in these clay minerals, and AQDS enhanced the reduction rate and extent. In the presence of AQDS, sulfate had little effect on Fe(III) bioreduction. In the absence of AQDS, sulfate increased the reduction rate and capacity, suggesting that sulfide produced during sulfate reduction reacted with the phyllosilicate Fe(III). The extent of bioreduction of structural Fe(III) in the clay minerals was positively correlated with the percentage of smectite and mineral surface area of these minerals. X-ray diffraction, and scanning and transmission electron microscopy results confirmed formation of illite after bioreduction. These data collectively showed that D. vulgaris could promote smectite illitization through reduction of structural Fe(III) in clay minerals. © 2011 Blackwell Publishing Ltd.

  9. Reduction of adsorbed As(V) on nano-TiO2 by sulfate-reducing bacteria.

    Science.gov (United States)

    Luo, Ting; Ye, Li; Ding, Cheng; Yan, Jinlong; Jing, Chuanyong

    2017-11-15

    Reduction of surface-bound arsenate [As(V)] and subsequent release into the aqueous phase contribute to elevated As in groundwater. However, this natural process is not fully understood, especially in the presence of sulfate-reducing bacteria (SRB). Gaining mechanistic insights into solid-As(V)-SRB interactions motivated our molecular level study on the fate of nano-TiO 2 bound As(V) in the presence of Desulfovibrio vulgaris DP4, a strain of SRB, using incubation and in situ ATR-FTIR experiments. The incubation results clearly revealed the reduction of As(V), either adsorbed on nano-TiO 2 or dissolved, in the presence of SRB. In contrast, this As(V) reduction was not observed in abiotic control experiments where sulfide was used as the reductant. Moreover, the reduction was faster for surface-bound As(V) than for dissolved As(V), as evidenced by the appearance of As(III) at 45h and 75h, respectively. ATR-FTIR results provided direct evidence that the surface-bound As(V) was reduced to As(III) on TiO 2 surfaces in the presence of SRB. In addition, the As(V) desorption from nano-TiO 2 was promoted by SRB relative to abiotic sulfide, due to the competition between As(V) and bacterial phosphate groups for TiO 2 surface sites. This competition was corroborated by the ATR-FTIR analysis, which showed inner-sphere surface complex formation by bacterial phosphate groups on TiO 2 surfaces. The results from this study highlight the importance of indirect bacteria-mediated As(V) reduction and release in geochemical systems. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Contribution to the study of the role of sulfate-reducing bacteria in bio-corrosion phenomenon

    International Nuclear Information System (INIS)

    Chatelus, C.

    1987-11-01

    By their metabolic activities of hydrogen consumption and of sulfides production, the sulfate-reducing bacteria are the main bacteria responsible of the metallic corrosion phenomena in the absence of oxygen. A physiological and enzymatic study of some Desulfovibrio has contributed to the understanding of the role of these bacteria in the anaerobic bio-corrosion phenomena. Desulfovibrio (D.) vulgaris in organic medium, after having oxidized the lactate, consumes the hydrogen formed by the electrochemical reaction of iron dissolution. The Desulfovibrio can be responsible either of a corrosion by a direct contact with the metal in using the H 2 layer formed at its surface, (bacteria are then adsorbed at the surface because of an iron sulfide crystalline lattice), or of a distant corrosion in consuming the dissolved or gaseous hydrogen. As their hydrogenases can be stable in time independently of the cellular structure (D. vulparis) and active at high temperatures (to 70 C - 75 C) (D. baculatus), these bacteria can act in conditions incompatible with the viability of cells but compatible with the enzymatic expression. A study in terms of temperature has shown that inside the mesophilic group of the Desulfovibrio, the behaviour towards this parameter is specific to each bacteria, that accounts for the permanent presence of the representatives of this population in sites where the temperature variations are important. A change of some degrees Celsius can induce modifications in the yields of bacteria growth and by a consequence in variations in the corrosion intensity. Moreover, sulfate D. multispirans can reduce with specific velocities of different growth, the nitrate, the nitrite and the fumarate. Some sulfato-reducing could then adapt themselves to the variations of concentrations in electron acceptors and metabolize the oxidized substances used as biocides too. The choice of an electron acceptor rather than another do not depend uniquely of the specificity of the

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

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, Kim F. [Univ. of Michigan, Ann Arbor, MI (United States); Bi, Yuqiang [Univ. of Michigan, Ann Arbor, MI (United States); Carpenter, Julian [Univ. of Michigan, Ann Arbor, MI (United States); Hyng, Sung Pil [Univ. of Michigan, Ann Arbor, MI (United States); Rittmann, Bruce E. [Arizona State Univ., Tempe, AZ (United States); Zhou, Chen [Arizona State Univ., Tempe, AZ (United States); Vannela, Raveender [Arizona State Univ., Tempe, AZ (United States); Davis, James A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2013-12-31

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

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

    Directory of Open Access Journals (Sweden)

    Korenblum Elisa

    2012-11-01

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

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

    Science.gov (United States)

    2012-01-01

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

  14. Homology modeling of dissimilatory APS reductases (AprBA of sulfur-oxidizing and sulfate-reducing prokaryotes.

    Directory of Open Access Journals (Sweden)

    Birte Meyer

    Full Text Available BACKGROUND: The dissimilatory adenosine-5'-phosphosulfate (APS reductase (cofactors flavin adenine dinucleotide, FAD, and two [4Fe-4S] centers catalyzes the transformation of APS to sulfite and AMP in sulfate-reducing prokaryotes (SRP; in sulfur-oxidizing bacteria (SOB it has been suggested to operate in the reverse direction. Recently, the three-dimensional structure of the Archaeoglobus fulgidus enzyme has been determined in different catalytically relevant states providing insights into its reaction cycle. METHODOLOGY/PRINCIPAL FINDINGS: Full-length AprBA sequences from 20 phylogenetically distinct SRP and SOB species were used for homology modeling. In general, the average accuracy of the calculated models was sufficiently good to allow a structural and functional comparison between the beta- and alpha-subunit structures (78.8-99.3% and 89.5-96.8% of the AprB and AprA main chain atoms, respectively, had root mean square deviations below 1 A with respect to the template structures. Besides their overall conformity, the SRP- and SOB-derived models revealed the existence of individual adaptations at the electron-transferring AprB protein surface presumably resulting from docking to different electron donor/acceptor proteins. These structural alterations correlated with the protein phylogeny (three major phylogenetic lineages: (1 SRP including LGT-affected Archaeoglobi and SOB of Apr lineage II, (2 crenarchaeal SRP Caldivirga and Pyrobaculum, and (3 SOB of the distinct Apr lineage I and the presence of potential APS reductase-interacting redox complexes. The almost identical protein matrices surrounding both [4Fe-4S] clusters, the FAD cofactor, the active site channel and center within the AprB/A models of SRP and SOB point to a highly similar catalytic process of APS reduction/sulfite oxidation independent of the metabolism type the APS reductase is involved in and the species it has been originated from. CONCLUSIONS: Based on the comparative

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

    Energy Technology Data Exchange (ETDEWEB)

    Truong, Hoang-Yen T. [Department of Biology, Laurentian University, Sudbury, Ontario, Canada P3E 2C6 (Canada); Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, Canada P3E 2C6 (Canada); Chen, Yu-Wei [Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, Canada P3E 2C6 (Canada); Belzile, Nelson, E-mail: nbelzile@laurentian.ca [Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, Canada P3E 2C6 (Canada); Cooperative Freshwater Ecology Unit, Laurentian University, Sudbury, Ontario, Canada P3E 2C6 (Canada)

    2013-04-01

    Cultures of the sulfate reducing bacteria Desulfovibrio desulfuricans were grown under anoxic conditions to study the effect of added sulfide, selenite and mercuric ions. A chemical trap consisting in a CuSO{sub 4} solution was used to control the poisoning effect induced by the bacterial production of hydrogen sulfide via the precipitation of CuS. Following the addition of Hg{sup 2+}, the formation of methylmercury (MeHg) was correlated to bacterial proliferation with most of MeHg found in the culture medium. A large fraction (50–80%) of added Hg{sup 2+} to a culture ended up in a solid phase (Hg{sup 0} and likely HgS) limiting its bioavailability to cells with elemental Hg representing ∼ 40% of the solid. Following the addition of selenite, a small fraction was converted into Se(0) inside the cells and, even though the conversion to this selenium species increased with the increase of added selenite, it never reached more than 49% of the added amount. The formation of volatile dimethylselenide is suggested as another detoxification mechanism. In cultures containing both added selenite and mercuric ions, elemental forms of the two compounds were still produced and the increase of selenium in the residual fraction of the culture suggests the formation of mercuric selenite limiting the bioavailability of both elements to cells. - Highlights: ► Detoxification mechanisms of D. desulfuricans were studied in presence of added sulfide, selenite and mercuric ions. ► The poisoning effect of H{sub 2}S added to or generated by cultures of D. desulfuricans can be controlled with a chemical trap. ► The addition of selenite to cultures triggered the formation of elemental Se and other forms of volatile and non-volatile Se. ► The addition of mercuric ions to cultures led to the production of methylmercury, volatile Hg and solid mercuric sulfide. ► With both Se and Hg added to cultures, fractionation of species in solid and liquid phases suggests the formation of HgSe.

  16. Desulfobacter psychrotolerans sp. nov., a new psychrotolerant sulfate-reducing bacterium and descriptions of its physiological response to temperature changes.

    Science.gov (United States)

    Tarpgaard, Irene H; Boetius, Antje; Finster, Kai

    2006-01-01

    A psychrotrolerant acetate-oxidizing sulfate-reducing bacterium (strain akvb(T)) was isolated from sediment from the northern part of The North Sea with annual temperature fluctuations between 8 and 14 degrees C. Of the various substrates tested, strain akvb(T) grew exclusively by the oxidation of acetate coupled to the reduction of sulfate. The cells were motile, thick rods with round ends and grew in dense aggregates. Strain akvb(T) grew at temperatures ranging from -3.6 to 26.3 degrees C. Optimal growth was observed at 20 degrees C. The highest cell specific sulfate reduction rate of 6.2 fmol cell(-1) d(-1) determined by the (35)SO(2-)(40) method was measured at 26 degrees C. The temperature range of short-term sulfate reduction rates exceeded the temperature range of growth by 5 degrees C. The Arrhenius relationship for the temperature dependence of growth and sulfate reduction was linear, with two distinct slopes below the optimum temperatures of both processes. The critical temperature was 6.4 degrees C. The highest growth yield (4.3-4.5 g dry weight mol(-1) acetate) was determined at temperatures between 5 and 15 degrees C. The cellular fatty acid composition was determined with cultures grown at 4 and 20 degrees C, respectively. The relative proportion of cellular unsaturated fatty acids (e.g. 16:1omega7c) was higher in cells grown at 4 degrees C than in cells grown at 20 degrees C. The physiological responses to temperature changes showed that strain akvb(T) was well adapted to the temperature regime of the environment from which it was isolated. Phylogenetic analysis showed that strain akvb(T) is closest related to Desulfobacter hydrogenophilus, with a 16S rRNA gene sequence similarity of 98.6%. DNA-DNA-hybridization showed a similarity of 32% between D. hydrogenophilus and strain akvb(T). Based on phenotypic and DNA-based characteristics we propose that strain akvb(T) is a member of a new species, Desulfobacter psychrotolerans sp. nov.

  17. Distribution of Sulfate-Reducing Bacteria, O2, and H2s in Photosynthetic Biofilms Determined by Oligonucleotide Probes and Microelectrodes Rid A-1977-2009

    DEFF Research Database (Denmark)

    RAMSING, NB; KUHL, M.; JØRGENSEN, BB

    1993-01-01

    The vertical distribution of sulfate-reducing bacteria (SRB) in photosynthetic biofilms from the trickling filter of a sewage treatment plant was investigated with oligonucleotide probes binding to 16S rRNA. To demonstrate the effect of daylight and photosynthesis and thereby of increased oxygen....... Fluorescent-dye-conjugated oligonucleotides were used as ''phylogenetic'' probes to identify single cells in the slices. Oligonucleotide sequences were selected which were complementary to short sequence elements (16 to 20 nucleotides) within the 16S rRNA of sulfate-reducing bacteria. The probes were labeled...... with fluorescein or rhodamine derivatives for subsequent visualization by epifluorescence microscopy. Five probes were synthesized for eukaryotes, eubacteria, SRB (including most species of the delta group of purple bacteria), Desulfobacter spp., and a nonhybridizing control. The SRB were unevenly distributed...

  18. Corrosion by sulfate-reducing bacteria in a HP gas line under a detached weld cladding; Korrosion durch sulfatreduzierende Bakterien an einer Hochdruckgasleitung unter abgeloester Schweissnahtnachumhuellung

    Energy Technology Data Exchange (ETDEWEB)

    Bette, Ulrich [Technische Akademie Wuppertal (Germany)

    2011-07-01

    Intelligent pig measurements detected several points of corrosion in a HP gas pipeline in northern Germany. Corrosion occurred in a pipe section buried in clay soil, under detached weld claddings. It was not detected in regular measurements and additional intensive measurements. When the pipes were dug up, sulfate-reducing bacteria were found as the cause of corrosion. Due to the location of the corrosion processes, cathodic protection was impossible, and IFO measurements were ineffective in the low-ohmic soil.

  19. Acetone utilization by sulfate-reducing bacteria: draft genome sequence of Desulfococcus biacutus and a proteomic survey of acetone-inducible proteins

    OpenAIRE

    Gutiérrez Acosta, Olga B; Schleheck, David; Schink, Bernhard

    2014-01-01

    Background The sulfate-reducing bacterium Desulfococcus biacutus is able to utilize acetone for growth by an inducible degradation pathway that involves a novel activation reaction for acetone with CO as a co-substrate. The mechanism, enzyme(s) and gene(s) involved in this acetone activation reaction are of great interest because they represent a novel and yet undefined type of activation reaction under strictly anoxic conditions. Results In this study, a draft genome sequence of D. biacutus ...

  20. Degradation of Phenol via Phenylphosphate and Carboxylation to 4-Hydroxybenzoate by a Newly Isolated Strain of the Sulfate-Reducing Bacterium Desulfobacterium anilini▿ †

    OpenAIRE

    Ahn, Young-Beom; Chae, Jong-Chan; Zylstra, Gerben J.; Häggblom, Max M.

    2009-01-01

    A sulfate-reducing phenol-degrading bacterium, strain AK1, was isolated from a 2-bromophenol-utilizing sulfidogenic estuarine sediment enrichment culture. On the basis of phylogenetic analysis of the 16S rRNA gene and DNA homology, strain AK1 is most closely related to Desulfobacterium anilini strain Ani1 (= DSM 4660T). In addition to phenol, this organism degrades a variety of other aromatic compounds, including benzoate, 2-hydroxybenzoate, 4-hydroxybenzoate, 4-hydroxyphenylacetate, 2-aminob...

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

    KAUST Repository

    Guan, Yue

    2015-11-01

    Oceanic deep hypersaline anoxic basins (DHABs) are characterized by drastic changes in physico-chemical conditions in the transition from overlaying seawater to brine body. Brine-seawater interfaces (BSIs) of several DHABs across the Mediterranean Sea have been shown to possess methanogenic and sulfate-reducing activities, yet no systematic studies have been conducted to address the potential functional diversity of methanogenic and sulfate-reducing communities in the Red Sea DHABs. Here, we evaluated the relative abundance of Bacteria and Archaea using quantitative PCR and conducted phylogenetic analyses of nearly full-length 16S rRNA genes as well as functional marker genes encoding the alpha subunits of methyl-coenzyme M reductase (mcrA) and dissimilatory sulfite reductase (dsrA). Bacteria predominated over Archaea in most locations, the majority of which were affiliated with Deltaproteobacteria, while Thaumarchaeota were the most prevalent Archaea in all sampled locations. The upper convective layers of Atlantis II Deep, which bear increasingly harsh environmental conditions, were dominated by members of the class Thermoplasmata (Marine Benthic Group E and Mediterranean Sea Brine Lakes Group 1). Our study revealed unique microbial compositions, the presence of niche-specific groups, and collectively, a higher diversity of sulfate-reducing communities compared to methanogenic communities in all five studied locations. © 2015 Institut Pasteur.

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

    KAUST Repository

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

    2015-01-01

    Oceanic deep hypersaline anoxic basins (DHABs) are characterized by drastic changes in physico-chemical conditions in the transition from overlaying seawater to brine body. Brine-seawater interfaces (BSIs) of several DHABs across the Mediterranean Sea have been shown to possess methanogenic and sulfate-reducing activities, yet no systematic studies have been conducted to address the potential functional diversity of methanogenic and sulfate-reducing communities in the Red Sea DHABs. Here, we evaluated the relative abundance of Bacteria and Archaea using quantitative PCR and conducted phylogenetic analyses of nearly full-length 16S rRNA genes as well as functional marker genes encoding the alpha subunits of methyl-coenzyme M reductase (mcrA) and dissimilatory sulfite reductase (dsrA). Bacteria predominated over Archaea in most locations, the majority of which were affiliated with Deltaproteobacteria, while Thaumarchaeota were the most prevalent Archaea in all sampled locations. The upper convective layers of Atlantis II Deep, which bear increasingly harsh environmental conditions, were dominated by members of the class Thermoplasmata (Marine Benthic Group E and Mediterranean Sea Brine Lakes Group 1). Our study revealed unique microbial compositions, the presence of niche-specific groups, and collectively, a higher diversity of sulfate-reducing communities compared to methanogenic communities in all five studied locations. © 2015 Institut Pasteur.

  3. Constraints on mechanisms and rates of anaerobic oxidation of methane by microbial consortia: process-based modeling of ANME-2 archaea and sulfate reducing bacteria interactions

    Directory of Open Access Journals (Sweden)

    B. Orcutt

    2008-11-01

    Full Text Available Anaerobic oxidation of methane (AOM is the main process responsible for the removal of methane generated in Earth's marine subsurface environments. However, the biochemical mechanism of AOM remains elusive. By explicitly resolving the observed spatial arrangement of methanotrophic archaea and sulfate reducing bacteria found in consortia mediating AOM, potential intermediates involved in the electron transfer between the methane oxidizing and sulfate reducing partners were investigated via a consortium-scale reaction transport model that integrates the effect of diffusional transport with thermodynamic and kinetic controls on microbial activity. Model simulations were used to assess the impact of poorly constrained microbial characteristics such as minimum energy requirements to sustain metabolism and cell specific rates. The role of environmental conditions such as the influence of methane levels on the feasibility of H2, formate and acetate as intermediate species, and the impact of the abundance of intermediate species on pathway reversal were examined. The results show that higher production rates of intermediates via AOM lead to increased diffusive fluxes from the methane oxidizing archaea to sulfate reducing bacteria, but the build-up of the exchangeable species can cause the energy yield of AOM to drop below that required for ATP production. Comparison to data from laboratory experiments shows that under the experimental conditions of Nauhaus et al. (2007, none of the potential intermediates considered here is able to support metabolic activity matching the measured rates.

  4. Acetone utilization by sulfate-reducing bacteria: draft genome sequence of Desulfococcus biacutus and a proteomic survey of acetone-inducible proteins.

    Science.gov (United States)

    Gutiérrez Acosta, Olga B; Schleheck, David; Schink, Bernhard

    2014-07-11

    The sulfate-reducing bacterium Desulfococcus biacutus is able to utilize acetone for growth by an inducible degradation pathway that involves a novel activation reaction for acetone with CO as a co-substrate. The mechanism, enzyme(s) and gene(s) involved in this acetone activation reaction are of great interest because they represent a novel and yet undefined type of activation reaction under strictly anoxic conditions. In this study, a draft genome sequence of D. biacutus was established. Sequencing, assembly and annotation resulted in 159 contigs with 5,242,029 base pairs and 4773 predicted genes; 4708 were predicted protein-encoding genes, and 3520 of these had a functional prediction. Proteins and genes were identified that are specifically induced during growth with acetone. A thiamine diphosphate-requiring enzyme appeared to be highly induced during growth with acetone and is probably involved in the activation reaction. Moreover, a coenzyme B12- dependent enzyme and proteins that are involved in redox reactions were also induced during growth with acetone. We present for the first time the genome of a sulfate reducer that is able to grow with acetone. The genome information of this organism represents an important tool for the elucidation of a novel reaction mechanism that is employed by a sulfate reducer in acetone activation.

  5. Methanogenesis in Thermophilic Biogas Reactors

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær

    1995-01-01

    Methanogenesis in thermophilic biogas reactors fed with different wastes is examined. The specific methanogenic activity with acetate or hydrogen as substrate reflected the organic loading of the specific reactor examined. Increasing the loading of thermophilic reactors stabilized the process as ....... Experiments using biogas reactors fed with cow manure showed that the same biogas yield found at 550 C could be obtained at 610 C after a long adaptation period. However, propionate degradation was inhibited by increasing the temperature.......Methanogenesis in thermophilic biogas reactors fed with different wastes is examined. The specific methanogenic activity with acetate or hydrogen as substrate reflected the organic loading of the specific reactor examined. Increasing the loading of thermophilic reactors stabilized the process...... as indicated by a lower concentration of volatile fatty acids in the effluent from the reactors. The specific methanogenic activity in a thermophilic pilot-plant biogas reactor fed with a mixture of cow and pig manure reflected the stability of the reactor. The numbers of methanogens counted by the most...

  6. Subcellular localization of proteins in the anaerobic sulfate reducer Desulfovibrio vulgaris via SNAP-tag labeling and photoconversion

    Energy Technology Data Exchange (ETDEWEB)

    Gorur, A.; Leung, C. M.; Jorgens, D.; Tauscher, A.; Remis, J. P.; Ball, D. A.; Chhabra, S.; Fok, V.; Geller, J. T.; Singer, M.; Hazen, T. C.; Juba, T.; Elias, D.; Wall, J.; Biggin, M.; Downing, K. H.; Auer, M.

    2010-06-01

    Systems Biology studies the temporal and spatial 3D distribution of macromolecular complexes with the aim that such knowledge will allow more accurate modeling of biological function and will allow mathematical prediction of cellular behavior. However, in order to accomplish accurate modeling precise knowledge of spatial 3D organization and distribution inside cells is necessary. And while a number of macromolecular complexes may be identified by its 3D structure and molecular characteristics alone, the overwhelming number of proteins will need to be localized using a reporter tag. GFP and its derivatives (XFPs) have been traditionally employed for subcelllar localization using photoconversion approaches, but this approach cannot be taken for obligate anaerobic bacteria, where the intolerance towards oxygen prevents XFP approaches. As part of the GTL-funded PCAP project (now ENIGMA) genetic tools have been developed for the anaerobe sulfate reducer Desulfovibrio vulgaris that allow the high-throughput generation of tagged-protein mutant strains, with a focus on the commercially available SNAP-tag cell system (New England Biolabs, Ipswich, MA), which is based on a modified O6-alkylguanine-DNA alkyltransferase (AGT) tag, that has a dead-end reaction with a modified O6-benzylguanine (BG) derivative and has been shown to function under anaerobic conditions. After initial challenges with respect to variability, robustness and specificity of the labeling signal we have optimized the labeling. Over the last year, as a result of the optimized labeling protocol, we now obtain robust labeling of 20 out of 31 SNAP strains. Labeling for 13 strains were confirmed at least five times. We have also successfully performed photoconversion on 5 of these 13 strains, with distinct labeling patterns for different strains. For example, DsrC robustly localizes to the periplasmic portion of the inner membrane, where as a DNA-binding protein localizes to the center of the cell, where the

  7. Molecular Analysis of the Diversity of Sulfate-Reducing and Sulfur-Oxidizing Prokaryotes in the Environment, Using aprA as Functional Marker Gene▿ †

    Science.gov (United States)

    Meyer, Birte; Kuever, Jan

    2007-01-01

    The dissimilatory adenosine-5′-phosposulfate reductase is a key enzyme of the microbial sulfate reduction and sulfur oxidation processes. Because the alpha- and beta-subunit-encoding genes, aprBA, are highly conserved among sulfate-reducing and sulfur-oxidizing prokaryotes, they are most suitable for molecular profiling of the microbial community structure of the sulfur cycle in environment. In this study, a new aprA gene-targeting assay using a combination of PCR and denaturing gradient gel electrophoresis is presented. The screening of sulfate-reducing and sulfur-oxidizing reference strains as well as the analyses of environmental DNA from diverse habitats (e.g., microbial mats, invertebrate tissue, marine and estuarine sediments, and filtered hydrothermal water) by the new primer pair revealed an improved microbial diversity coverage and less-pronounced template-to-PCR product bias in direct comparison to those of the previously published primer set (B. Deplancke, K. R. Hristova, H. A. Oakley, V. J. McCracken, R. Aminov, R. I. Mackie, and H. R. Gaskins, Appl. Environ. Microbiol. 66:2166-2174, 2000). The concomitant molecular detection of sulfate-reducing and sulfur-oxidizing prokaryotes was confirmed. The new assay was applied in comparison with the 16S rRNA gene-based analysis to investigate the microbial diversity of the sulfur cycle in sediment, seawater, and manganese crust samples from four study sites in the area of the Lesser Antilles volcanic arc, Caribbean Sea (Caribflux project). The aprA gene-based approach revealed putative sulfur-oxidizing Alphaproteobacteria of chemolithoheterotrophic lifestyle to have been abundant in the nonhydrothermal sediment and water column. In contrast, the sulfur-based microbial community that inhabited the surface of the volcanic manganese crust was more complex, consisting predominantly of putative chemolithoautotrophic sulfur oxidizers of the Betaproteobacteria and Gammaproteobacteria. PMID:17921272

  8. Molecular analysis of the diversity of sulfate-reducing and sulfur-oxidizing prokaryotes in the environment, using aprA as functional marker gene.

    Science.gov (United States)

    Meyer, Birte; Kuever, Jan

    2007-12-01

    The dissimilatory adenosine-5'-phosphosulfate reductase is a key enzyme of the microbial sulfate reduction and sulfur oxidation processes. Because the alpha- and beta-subunit-encoding genes, aprBA, are highly conserved among sulfate-reducing and sulfur-oxidizing prokaryotes, they are most suitable for molecular profiling of the microbial community structure of the sulfur cycle in environment. In this study, a new aprA gene-targeting assay using a combination of PCR and denaturing gradient gel electrophoresis is presented. The screening of sulfate-reducing and sulfur-oxidizing reference strains as well as the analyses of environmental DNA from diverse habitats (e.g., microbial mats, invertebrate tissue, marine and estuarine sediments, and filtered hydrothermal water) by the new primer pair revealed an improved microbial diversity coverage and less-pronounced template-to-PCR product bias in direct comparison to those of the previously published primer set (B. Deplancke, K. R. Hristova, H. A. Oakley, V. J. McCracken, R. Aminov, R. I. Mackie, and H. R. Gaskins, Appl. Environ. Microbiol. 66:2166-2174, 2000). The concomitant molecular detection of sulfate-reducing and sulfur-oxidizing prokaryotes was confirmed. The new assay was applied in comparison with the 16S rRNA gene-based analysis to investigate the microbial diversity of the sulfur cycle in sediment, seawater, and manganese crust samples from four study sites in the area of the Lesser Antilles volcanic arc, Caribbean Sea (Caribflux project). The aprA gene-based approach revealed putative sulfur-oxidizing Alphaproteobacteria of chemolithoheterotrophic lifestyle to have been abundant in the nonhydrothermal sediment and water column. In contrast, the sulfur-based microbial community that inhabited the surface of the volcanic manganese crust was more complex, consisting predominantly of putative chemolithoautotrophic sulfur oxidizers of the Betaproteobacteria and Gammaproteobacteria.

  9. Obligate sugar oxidation in Mesotoga spp., phylum Thermotogae, in the presence of either elemental sulfur or hydrogenotrophic sulfate-reducers as electron acceptor

    OpenAIRE

    Fadhlaoui, K.; Ben Hania, W.; Armougom, Fabrice; Bartoli, M.; Fardeau, Marie-Laure; Erauso, G.; Brasseur, G.; Aubert, C.; Hamdi, M.; Brochier-Armanet, C.; Dolla, A.; Ollivier, Bernard

    2018-01-01

    Mesotoga prima strain PhosAc3 is a mesophilic representative of the phylum Thermotogae comprising only fermentative bacteria so far. We show that while unable to ferment glucose, this bacterium is able to couple its oxidation to reduction of elemental sulfur. We demonstrate furthermore that M. prima strain PhosAc3 as well as M. prima strain MesG1 and Mesotoga infera are able to grow in syntrophic association with sulfate-reducing bacteria (SRB) acting as hydrogen scavengers through interspeci...

  10. Summary report on the aerobic degradation of diesel fuel and the degradation of toluene under aerobic, denitrifying and sulfate reducing conditions

    International Nuclear Information System (INIS)

    Coyne, P.; Smith, G.

    1995-01-01

    This report contains a number of studies that were performed to better understand the technology of the biodegradation of petroleum hydrocarbons. Topics of investigation include the following: diesel fuel degradation by Rhodococcus erythropolis; BTEX degradation by soil isolates; aerobic degradation of diesel fuel-respirometry; aerobic degradation of diesel fuel-shake culture; aerobic toluene degradation by A3; effect of HEPES, B1, and myo-inositol addition on the growth of A3; aerobic and anaerobic toluene degradation by contaminated soils; denitrifying bacteria MPNs; sulfate-reducing bacteria MPNs; and aerobic, DNB and SRB enrichments

  11. Anoxybacillus kamchatkensis subsp. asaccharedens subsp. nov., a thermophilic bacterium isolated from a hot spring in Batman.

    Science.gov (United States)

    Gul-Guven, Reyhan; Guven, Kemal; Poli, Annarita; Nicolaus, Barbara

    2008-12-01

    A new thermophilic spore-forming strain KG8(T) was isolated from the mud of Taslidere hot spring in Batman. Strain KG8(T) was aerobe, Gram-positive, rod-shaped, motile, occurring in pairs or filamentous. Growth was observed from 35-65 degrees C (optimum 55 degrees C) and at pH 5.5-9.5 (optimum pH 7.5). It was capable of utilizing starch, growth was observed until 3% NaCl (w/v) and it was positive for nitrate reduction. On the basis of 16S rRNA gene sequence similarity, strain KG8(T) was shown to be related most closely to Anoxybacillus species. Chemotaxonomic data (major isoprenoid quinone-menaquinone-7; major fatty acid-iso-C15:0 and iso-C17:0) supported the affiliation of strain KG8(T) to the genus Anoxybacillus. The results of DNA-DNA hybridization, physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain KG8(T). Based on these results we propose assigning a novel subspecies of Anoxybacillus kamchatkensis, to be named Anoxybacillus kamchatkensis subsp. asaccharedens subsp. nov. with the type strain KG8(T) (DSM 18475(T)=CIP 109280(T)).

  12. Production and properties of two types of xylanases from alkalophilic thermophilic Bacillus spp

    Energy Technology Data Exchange (ETDEWEB)

    Okazaki, W; Akahoshi, R; Akiba, T; Horikoshi, K

    1984-05-01

    Four strains (W1, W2, W3, and W4) of alkalophilic thermophilic bacteria which produced xylanase were isolated from soils. They were aerobic, spore-forming. Gram-positive, and rod-shaped bacteria and hence identified as the genus Bacillus. The optimal temperatures for growth of the four strains were between 45/sup 0/C and 50/sup 0/C and pH optima were between 9.0 and 10.0. No growth occurred below pH 7.0 or above 55/sup 0/C. The four strains produced xylanases in medium containing xylan or xylose under these conditions. The optimal pH and temperature for activities of the four xylanases ranged from 6.0 to 7.0 and from 65/sup 0/C to 70/sup 0/C, respectively. The four xylanases were stable in the wide pH range from 4.5 to 10.5 at 45/sup 0/C for 1 h. All xylanases split xylan to yield xylose and xylobiose.

  13. Spore-Forming Bacteria that Resist Sterilization

    Science.gov (United States)

    LaDuc, Myron; Venkateswaran, Kasthuri

    2003-01-01

    A report presents a phenotypic and genotypic characterization of a bacterial species that has been found to be of the genus Bacillus and has been tentatively named B. odysseensis because it was isolated from surfaces of the Mars Odyssey spacecraft as part of continuing research on techniques for sterilizing spacecraft to prevent contamination of remote planets by terrestrial species. B. odysseensis is a Gram-positive, facultatively anaerobic, rod-shaped bacterium that forms round spores. The exosporium has been conjectured to play a role in the elevated resistance to sterilization. Research on the exosporium is proposed as a path toward improved means of sterilization, medical treatment, and prevention of biofouling.

  14. Diversity and Composition of Sulfate-Reducing Microbial Communities Based on Genomic DNA and RNA Transcription in Production Water of High Temperature and Corrosive Oil Reservoir

    Directory of Open Access Journals (Sweden)

    Xiao-Xiao Li

    2017-06-01

    Full Text Available Deep subsurface petroleum reservoir ecosystems harbor a high diversity of microorganisms, and microbial influenced corrosion is a major problem for the petroleum industry. Here, we used high-throughput sequencing to explore the microbial communities based on genomic 16S rDNA and metabolically active 16S rRNA analyses of production water samples with different extents of corrosion from a high-temperature oil reservoir. Results showed that Desulfotignum and Roseovarius were the most abundant genera in both genomic and active bacterial communities of all the samples. Both genomic and active archaeal communities were mainly composed of Archaeoglobus and Methanolobus. Within both bacteria and archaea, the active and genomic communities were compositionally distinct from one another across the different oil wells (bacteria p = 0.002; archaea p = 0.01. In addition, the sulfate-reducing microorganisms (SRMs were specifically assessed by Sanger sequencing of functional genes aprA and dsrA encoding the enzymes adenosine-5′-phosphosulfate reductase and dissimilatory sulfite reductase, respectively. Functional gene analysis indicated that potentially active Archaeoglobus, Desulfotignum, Desulfovibrio, and Thermodesulforhabdus were frequently detected, with Archaeoglobus as the most abundant and active sulfate-reducing group. Canonical correspondence analysis revealed that the SRM communities in petroleum reservoir system were closely related to pH of the production water and sulfate concentration. This study highlights the importance of distinguishing the metabolically active microorganisms from the genomic community and extends our knowledge on the active SRM communities in corrosive petroleum reservoirs.

  15. Diversity and Composition of Sulfate-Reducing Microbial Communities Based on Genomic DNA and RNA Transcription in Production Water of High Temperature and Corrosive Oil Reservoir

    Science.gov (United States)

    Li, Xiao-Xiao; Liu, Jin-Feng; Zhou, Lei; Mbadinga, Serge M.; Yang, Shi-Zhong; Gu, Ji-Dong; Mu, Bo-Zhong

    2017-01-01

    Deep subsurface petroleum reservoir ecosystems harbor a high diversity of microorganisms, and microbial influenced corrosion is a major problem for the petroleum industry. Here, we used high-throughput sequencing to explore the microbial communities based on genomic 16S rDNA and metabolically active 16S rRNA analyses of production water samples with different extents of corrosion from a high-temperature oil reservoir. Results showed that Desulfotignum and Roseovarius were the most abundant genera in both genomic and active bacterial communities of all the samples. Both genomic and active archaeal communities were mainly composed of Archaeoglobus and Methanolobus. Within both bacteria and archaea, the active and genomic communities were compositionally distinct from one another across the different oil wells (bacteria p = 0.002; archaea p = 0.01). In addition, the sulfate-reducing microorganisms (SRMs) were specifically assessed by Sanger sequencing of functional genes aprA and dsrA encoding the enzymes adenosine-5′-phosphosulfate reductase and dissimilatory sulfite reductase, respectively. Functional gene analysis indicated that potentially active Archaeoglobus, Desulfotignum, Desulfovibrio, and Thermodesulforhabdus were frequently detected, with Archaeoglobus as the most abundant and active sulfate-reducing group. Canonical correspondence analysis revealed that the SRM communities in petroleum reservoir system were closely related to pH of the production water and sulfate concentration. This study highlights the importance of distinguishing the metabolically active microorganisms from the genomic community and extends our knowledge on the active SRM communities in corrosive petroleum reservoirs. PMID:28638372

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

    Science.gov (United States)

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

    2016-03-29

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

  17. Decontamination of acid mine water from Ronneburg/Thueringen which is high in sulfates and metals using sulfate-reducing bacteria. Final report of the preliminary phase

    International Nuclear Information System (INIS)

    Hard, B.; Friedrich, S.

    1995-01-01

    The mining in Eastern Europe, particularly in East-Germany, is a major source of pollution to the surrounding areas of the mines. With the end of the cold war the demand for uranium has drastically declined. Many of the pits have therefore been closed down or are in the process of closure such as the uranium mine in Ronneburg in Thueringen. One major problem is the safe-making of the pits and dumps as they are highly radioactive through naturally occurring uranium and other radioactive elements. Because of the leaching process through bacteria, drainage water is very acidic, with pH-values between 1-2. The water is very rich in magnesium, iron and aluminium sulfate. Here the application of a microbial process to decontaminate acid mine drainage was investigated. Decontamination of the water includes: - Increase in pH - decrease in sulfate concentrations - minimization of the metal and radionuclide load. Sulfate-reducing bacteria seem suitable for this process. In order for such a microbial process to be economically viable a cheap and widely available electron donar has to be used eg. methanol. The work carried out reports on the isolation, characterization and physiology of sulfate-reducing methylotrophic bacteria and their suitability for a decontamination process of sulfuric acid uranium mine water. (orig.) [de

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2016-03-01

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

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

    Science.gov (United States)

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

    2010-12-01

    Processes leading to the bioaccumulation of methylmercury (MeHg) in northern wetlands are largely unknown. We have studied various ecological niches within a remote, acidic forested lake ecosystem in the southwestern Adirondacks, NY, to discover that mats comprised of Sphagnum moss were a hot spot for mercury (Hg) and MeHg accumulation (190.5 and 18.6 ng g⁻¹ dw, respectively). Furthermore, significantly higher potential methylation rates were measured in Sphagnum mats as compared with other sites within Sunday Lake's ecosystem. Although MPN estimates showed a low biomass of sulfate-reducing bacteria (SRB), 2.8 × 10⁴ cells mL⁻¹ in mat samples, evidence consisting of (1) a twofold stimulation of potential methylation by the addition of sulfate, (2) a significant decrease in Hg methylation in the presence of the sulfate reduction inhibitor molybdate, and (3) presence of dsrAB-like genes in mat DNA extracts, suggested that SRB were involved in Hg methylation. Sequencing of dsrB genes indicated that novel SRB, incomplete oxidizers including Desulfobulbus spp. and Desulfovibrio spp., and syntrophs dominated the sulfate-reducing guild in the Sphagnum moss mat. Sphagnum, a bryophyte dominating boreal peatlands, and its associated microbial communities appear to play an important role in the production and accumulation of MeHg in high-latitude ecosystems. © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  1. The first genomic and proteomic characterization of a deep-sea sulfate reducer: insights into the piezophilic lifestyle of Desulfovibrio piezophilus.

    Directory of Open Access Journals (Sweden)

    Nathalie Pradel

    Full Text Available Desulfovibrio piezophilus strain C1TLV30(T is a piezophilic anaerobe that was isolated from wood falls in the Mediterranean deep-sea. D. piezophilus represents a unique model for studying the adaptation of sulfate-reducing bacteria to hydrostatic pressure. Here, we report the 3.6 Mbp genome sequence of this piezophilic bacterium. An analysis of the genome revealed the presence of seven genomic islands as well as gene clusters that are most likely linked to life at a high hydrostatic pressure. Comparative genomics and differential proteomics identified the transport of solutes and amino acids as well as amino acid metabolism as major cellular processes for the adaptation of this bacterium to hydrostatic pressure. In addition, the proteome profiles showed that the abundance of key enzymes that are involved in sulfate reduction was dependent on hydrostatic pressure. A comparative analysis of orthologs from the non-piezophilic marine bacterium D. salexigens and D. piezophilus identified aspartic acid, glutamic acid, lysine, asparagine, serine and tyrosine as the amino acids preferentially replaced by arginine, histidine, alanine and threonine in the piezophilic strain. This work reveals the adaptation strategies developed by a sulfate reducer to a deep-sea lifestyle.

  2. Comparative study in the induced corrosion by sulfate reducing microorganisms, in a stainless steel 304L sensitized and a carbon steel API X65

    International Nuclear Information System (INIS)

    Diaz S, A.; Gonzalez F, E.; Arganis J, C.; Luna C, P.; Carapia M, L.

    2004-01-01

    In spite of the operational experience related with the presence of the phenomenon of microbiological corrosion (MIC) in industrial components, it was not but until the decade of the 80 s when the nuclear industry recognized its influence in some systems of Nuclear Generating Power plants. At the moment, diverse studies that have tried to explain the generation mechanism of this phenomenon exist; however, they are even important queries that to solve, especially those related with the particularities of the affected metallic substrates. Presently work, the electrochemical behavior of samples of stainless steel AISI 304L sensitized is evaluated and the carbon steel APIX65, before the action of sulfate reducing microorganisms low the same experimental conditions; found that for the APIX65 the presence of this type of bacteria promoted the formation of a stable biofilm that allowed the maintenance of the microorganisms that damaged the material in isolated places where stings were generated; while in the AISI 304L, it was not detected damage associated to the inoculated media. The techniques of Resistance to the Polarization and Tafel Extrapolation, allowed the calculation of the speed of uniform corrosion, parameter that doesn't seem to be influenced by the presence of the microorganisms; while that noise electrochemical it distinguished in real time, the effect of the sulfate reducing in the steel APIX65. (Author)

  3. Obligate sugar oxidation in Mesotoga spp., phylum Thermotogae, in the presence of either elemental sulfur or hydrogenotrophic sulfate-reducers as electron acceptor.

    Science.gov (United States)

    Fadhlaoui, Khaled; Ben Hania, Wagdi; Armougom, Fabrice; Bartoli, Manon; Fardeau, Marie-Laure; Erauso, Gaël; Brasseur, Gaël; Aubert, Corinne; Hamdi, Moktar; Brochier-Armanet, Céline; Dolla, Alain; Ollivier, Bernard

    2018-01-01

    Mesotoga prima strain PhosAc3 is a mesophilic representative of the phylum Thermotogae comprising only fermentative bacteria so far. We show that while unable to ferment glucose, this bacterium is able to couple its oxidation to reduction of elemental sulfur. We demonstrate furthermore that M. prima strain PhosAc3 as well as M. prima strain MesG1 and Mesotoga infera are able to grow in syntrophic association with sulfate-reducing bacteria (SRB) acting as hydrogen scavengers through interspecies hydrogen transfer. Hydrogen production was higher in M. prima strain PhosAc3 cells co-cultured with SRB than in cells cultured alone in the presence of elemental sulfur. We propose that the efficient sugar-oxidizing metabolism by M. prima strain PhosAc3 in syntrophic association with a hydrogenotrophic sulfate-reducing bacterium can be extrapolated to all members of the Mesotoga genus. Genome comparison of Thermotogae members suggests that the metabolic difference between Mesotoga and Thermotoga species (sugar oxidation versus fermentation) is mainly due to the absence of the bifurcating [FeFe]-hydrogenase in the former. Such an obligate oxidative process for using sugars, unusual within prokaryotes, is the first reported within the Thermotogae. It is hypothesized to be of primary ecological importance for growth of Mesotoga spp. in the environments that they inhabit. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  4. Anaerobic thermophilic culture-system

    Energy Technology Data Exchange (ETDEWEB)

    Ljungdahl, L G; Wiegel, J K.W.

    1981-04-14

    A mixed culture system of Thermoanaerobacter ethanolicus and Clostridium thermocellum is employed for anaerobic, thermophilic ethanol fermentation of cellulose. By cellulase action, monosaccharides are formed which inhibit the growth of C. thermocellum, but are fermented by T. ethanolicus. Thus, at a regulated pH-value of 7.5, this mixed culture system of micro organisms results in a cellulose fermentation with a considerably higher ethanol yield.

  5. Hydrogen limitation and syntrophic growth among natural assemblages of thermophilic methanogens at deep-sea hydrothermal vents

    Directory of Open Access Journals (Sweden)

    Begüm D. Topçuoğlu

    2016-08-01

    Full Text Available Thermophilic methanogens are common autotrophs at hydrothermal vents, but their growth constraints and dependence on H2 syntrophy in situ are poorly understood. Between 2012 and 2015, methanogens and H2-producing heterotrophs were detected by growth at 80°C and 55°C at most diffuse (7-40°C hydrothermal vent sites at Axial Seamount. Microcosm incubations of diffuse hydrothermal fluids at 80°C and 55°C demonstrated that growth of thermophilic and hyperthermophilic methanogens is primarily limited by H2 availability. Amendment of microcosms with NH4+ generally had no effect on CH4 production. However, annual variations in abundance and CH4 production were observed in relation to the eruption cycle of the seamount. Microcosm incubations of hydrothermal fluids at 80°C and 55°C supplemented with tryptone and no added H2 showed CH4 production indicating the capacity in situ for methanogenic H2 syntrophy. 16S rRNA genes were found in 80°C microcosms from H2-producing archaea and H2-consuming methanogens, but not for any bacteria. In 55°C microcosms, sequences were found from the H2-producing bacteria and H2-consuming methanogens and sulfate-reducing bacteria. A co-culture of representative organisms showed that Thermococcus paralvinellae supported the syntrophic growth of Methanocaldococcus bathoardescens at 82°C and Methanothermococcus sp. strain BW11 at 60°C. The results demonstrate that modeling of subseafloor methanogenesis should focus primarily on H2 availability and temperature, and that thermophilic H2 syntrophy can support methanogenesis within natural microbial assemblages and may be an important energy source for thermophilic autotrophs in marine geothermal environments.

  6. The roles of the micro-organisms and chromium content in the corrosion of iron-chromium steels in the presence of sulfate-reducing bacteria

    International Nuclear Information System (INIS)

    Ferrante, V.

    1991-09-01

    If it is widely accepted that the presence of sulfate-reducing bacteria can increase the aqueous corrosion of steels, the induced mechanisms are still not definitively established. The aim of this work is to specify the roles, for corrosion, of the presence of bacteria (D. Vulgaris) in one part and of chemical parameters as the composition of the material and the accumulation of sulfides in another part. The use of experimental techniques coming from microbiology, electrochemistry or chemical analysis has revealed the interdependence which exists between the bacteria and the material, and the importance of the steel composition towards the adhesion of microorganisms and the generalized corrosion. The bacteria and the dissolved sulfides do not seem to influence remarkably the generalized corrosion. Nevertheless, the alterations of the surface state they induce could be the cause of localized corrosion phenomena. (O.M.)

  7. Prokaryotic community structure and activity of sulfate reducers in production water from high-temperature oil reservoirs with and without nitrate treatment

    DEFF Research Database (Denmark)

    Gittel, Antje; Sørensen, Ketil; Skovhus, Torben L.

    2009-01-01

    Sulfate-reducing prokaryotes (SRP) cause severe problems like microbial corrosion and reservoir souring in seawater-injected oil production systems. One strategy to control SRP activity is the addition of nitrate to the injection water. Production waters from two adjacent, hot (80°C) oil reservoirs......, one with and one without nitrate treatment, were compared for prokaryotic community structure and activity of SRP. Bacterial and archaeal 16S rRNA gene analyses revealed higher prokaryotic abundance but lower diversity for the nitrate-treated field. The 16S rRNA gene clone libraries from both fields...... were dominated by sequences affiliated with Firmicutes (Bacteria) and Thermococcales (Archaea). Potential heterotrophic nitrate reducers (Deferribacterales) were exclusively found at the nitrate-treated field, possibly stimulated by nitrate addition. Quantitative PCR of dsrAB genes revealed...

  8. The impact of temperature change on the activity and community composition of sulfate-reducing bacteria in arctic versus temperate marine sediments

    DEFF Research Database (Denmark)

    Robador, Alberto; Brüchert, Volker; Jørgensen, Bo Barker

    2009-01-01

    Arctic regions may be particularly sensitive to climate warming and, consequently, rates of carbon mineralization in warming marine sediment may also be affected. Using long-term (24 months) incubation experiments at 0°C, 10°C and 20°C, the temperature response of metabolic activity and community...... composition of sulfate-reducing bacteria were studied in the permanently cold sediment of north-western Svalbard (Arctic Ocean) and compared with a temperate habitat with seasonally varying temperature (German Bight, North Sea). Short-term 35S-sulfate tracer incubations in a temperature-gradient block...... (between -3.5°C and +40°C) were used to assess variations in sulfate reduction rates during the course of the experiment. Warming of arctic sediment resulted in a gradual increase of the temperature optima (Topt) for sulfate reduction suggesting a positive selection of psychrotolerant/mesophilic sulfate...

  9. Effect of nitrate addition on the diversity and activity of sulfate-reducing prokaryotes in high-temperature oil production systems

    DEFF Research Database (Denmark)

    Gittel, Antje; Wieczorek, Adam; Sørensen, Ketil

    Sulfate-reducing prokaryotes (SRP) producing hydrogen sulfide cause severe problems like microbial corrosion, souring and plugging in seawater-injected oil production systems. Adding nitrate to the injection water is a possible strategy to control the activity of SRP by favoring the growth of both...... heterotrophic, nitrate-reducing bacteria that outcompete SRP for substrates, and nitrate-reducing, sulfide-oxidizing bacteria (NR-SOB). To assess the effects of nitrate addition, microbial diversity (Bacteria, Archaea) and SRP activity were studied in the production waters of a nitrate-treated and a non...... their potential activity under pipeline (60°C), but not under oil reservoir conditions (80°C), indicating that the troublesome SRP were pipeline-derived. Consistent with the low amount of SRP, no activity could be shown for samples from the nitrate-treated system suggesting that SRP were inhibited by nitrate...

  10. Effect of nitrate addition on prokaryotic diversity and the activity of sulfate-reducing prokaryotes in high-temperature oil production systems

    DEFF Research Database (Denmark)

    Gittel, Antje; Wieczorek, Adam; Sørensen, Ketil

    Adding nitrate to injection water is a possible strategy to control the activity of sulfate-reducing prokaryotes (SRP) in oil production system. To assess the effects of nitrate addition, prokaryotic diversity (Bacteria, Archaea, SRP) and SRP activity were studied in the production waters......-treated site was additionally supported by demonstrating their potential activity at 58°C, indicating that the troublesome SRP were pipeline-derived. Consistent with the low frequency of SRP in the clone libraries, no activity could be shown for samples from the nitrate-treated system suggesting that SRP were...... inhibited by nitrate addition. Visualization and quantification of the identified troublesome prokaryotes and potential competitors using the CARD-FISH technique will be performed on production water from both sites....

  11. The roles of the micro-organisms and chromium content in the corrosion of iron-chromium steels in the presence of sulfate-reducing bacteria

    International Nuclear Information System (INIS)

    Ferrante, V.

    1991-12-01

    Although the ability of sulfate-reducing bacteria to enhance the corrosion of steel is now widely accepted, the actual processes involved in such phenomena are still discussed. This work is dedicated to the study of the exact roles played in corrosion processes firstly, by the presence of D. vulgaris cells and, secondly, by chemical factors such as the material composition and the accumulation of sulfide ions in the solution. The use of microbiological, electrochemical and analytical experimental techniques lead to results that show the interdependence of the bacteria and the material as well as the importance of the steel composition in the adhesion of the micro-organisms and the general corrosion rates. The bacteria cells and dissolved sulfide ions do not markedly influence the general corrosion rates. They however induce surface state modifications that can result in localized corrosion phenomena

  12. Microbial conversion of sulfur dioxide in flue gas to sulfide using bulk drug industry wastewater as an organic source by mixed cultures of sulfate reducing bacteria

    International Nuclear Information System (INIS)

    Rao, A. Gangagni; Ravichandra, P.; Joseph, Johny; Jetty, Annapurna; Sarma, P.N.

    2007-01-01

    Mixed cultures of sulfate reducing bacteria (SRB) were isolated from anaerobic cultures and enriched with SRB media. Studies on batch and continuous reactors for the removal of SO 2 with bulk drug industry wastewater as an organic source using isolated mixed cultures of SRB revealed that isolation and enrichment methodology adopted in the present study were apt to suppress the undesirable growth of anaerobic bacteria other than SRB. Studies on anaerobic reactors showed that process was sustainable at COD/S ratio of 2.2 and above with optimum sulfur loading rate (SLR) of 5.46 kg S/(m 3 day), organic loading rate (OLR) of 12.63 kg COD/(m 3 day) and at hydraulic residence time (HRT) of 8 h. Free sulfide (FS) concentration in the range of 300-390 mg FS/l was found to be inhibitory to mixed cultures of SRB used in the present studies

  13. Influence of Gamma Radiation on the Treatment of Sulfate Reducing Bacteria in the Injection Water Used for the Enhanced Oil Recovery

    International Nuclear Information System (INIS)

    El-Shahawy, M.R.; Ramzi, M.; Farag, R.M.

    2014-01-01

    The counts of sulfate reducing bacteria (SRB) in the water samples collected from the well head (formation water) and outlet of petroleum treatment plant (Produced water) in a petroleum field in middle delta- Egypt were determined. The data showed a low count of (SRB) in the collected formation water sample and there was an obvious increase in the bacterial counts which appeared in the produced water, that may reveal that the presence of appropriate conditions for the growth of (SRB) in the closed system in treatment plant. Two scale inhibitors were tested through jar test, the scale inhibitor I had maximum efficiency at 20 ppm, two SRB biocides were screened for their bactericidal activities. It was found that the biocides A was slightly superior in respect to the antibacterial efficacy compared to B in presence of 20 ppm scale inhibitor. These biocides were test for the study of the combined treatment with gamma radiation to maximize the efficiency on sulfate reducing bacteria using the minimum effective dose of both radiation and biocides to eliminate the negative impacts of the chemicals used and the radiation applied. The results demonstrated that, the lethal doses of biocides were (300 ppm) of biocides A or (400 ppm) of biocides B at 1 kGy irradiation dose. The treated produced water was evaluated in respect of enhanced oil recovery, the data showed increase of the recovery capacity by the irradiation and chemical treatment. This technology could be used for the water that are injected into reservoirs, and suitable for oil field and pipeline operators, and presented a viable bacteria control method

  14. Triterpenoid herbal saponins enhance beneficial bacteria, decrease sulfate-reducing bacteria, modulate inflammatory intestinal microenvironment and exert cancer preventive effects in ApcMin/+ mice

    Science.gov (United States)

    Chen, Lei; Brar, Manreetpal S.; Leung, Frederick C. C.; Hsiao, W. L. Wendy

    2016-01-01

    Saponins derived from medicinal plants have raised considerable interest for their preventive roles in various diseases. Here, we investigated the impacts of triterpenoid saponins isolated from Gynostemma pentaphyllum (GpS) on gut microbiome, mucosal environment, and the preventive effect on tumor growth. Six-week old ApcMin/+ mice and their wild-type littermates were fed either with vehicle or GpS daily for the duration of 8 weeks. The fecal microbiome was analyzed by enterobacterial repetitive intergenic consensus (ERIC)-PCR and 16S rRNA gene pyrosequencing. Study showed that GpS treatment significantly reduced the number of intestinal polyps in a preventive mode. More importantly, GpS feeding strikingly reduced the sulfate-reducing bacteria lineage, which are known to produce hydrogen sulfide and contribute to damage the intestinal epithelium or even promote cancer progression. Meanwhile, GpS also boosted the beneficial microbes. In the gut barrier of the ApcMin/+ mice, GpS treatment increased Paneth and goblet cells, up-regulated E-cadherin and down-regulated N-cadherin. In addition, GpS decreased the pro-oncogenic β-catenin, p-Src and the p-STAT3. Furthermore, GpS might also improve the inflamed gut epithelium of the ApcMin/+ mice by upregulating the anti-inflammatory cytokine IL-4, while downregulating pro-inflammatory cytokines TNF-β, IL-1β and IL-18. Intriguingly, GpS markedly stimulated M2 and suppressed M1 macrophage markers, indicating that GpS altered mucosal cytokine profile in favor of the M1 to M2 macrophages switching, facilitating intestinal tissue repair. In conclusion, GpS might reverse the host's inflammatory phenotype by increasing beneficial bacteria, decreasing sulfate-reducing bacteria, and alleviating intestinal inflammatory gut environment, which might contribute to its cancer preventive effects. PMID:27121311

  15. Desulfomusa hansenii gen. nov., sp. nov., a novel marine propionate-degrading, sulfate-reducing bacterium isolated from Zostera marina roots.

    Science.gov (United States)

    Finster, K; Thomsen, T R; Ramsing, N B

    2001-11-01

    The physiology and phylogeny of a novel sulfate-reducing bacterium, isolated from surface-sterilized roots of the marine macrophyte Zostera marina, are presented. The strain, designated P1T, was enriched and isolated in defined oxygen-free, bicarbonate-buffered, iron-reduced seawater medium with propionate as sole carbon source and electron donor and sulfate as electron acceptor. Strain P1T had a rod-shaped, slightly curved cell morphology and was motile by means of a single polar flagellum. Cells generally aggregated in clumps throughout the growth phase. High CaCl2 (10 mM) and MgCl2 (50 mM) concentrations were required for optimum growth. In addition to propionate, strain P1T utilized fumarate, succinate, pyruvate, ethanol, butanol and alanine. Oxidation of propionate was incomplete and acetate was formed in stoichiometric amounts. Strain P1T thus resembles members of the sulfate-reducing genera Desulfobulbus and Desulforhopalus, which both oxidize propionate incompletely and form acetate in addition to CO2. However, sequence analysis of the small-subunit rDNA and the dissimilatory sulfite reductase gene revealed that strain P1T was unrelated to the incomplete oxidizers Desulfobulbus and Desulforhopalus and that it constitutes a novel lineage affiliated with the genera Desulfococcus, Desulfosarcina, Desulfonema and 'Desulfobotulus'. Members of this branch, with the exception of 'Desulfobotulus sapovorans', oxidize a variety of substrates completely to CO2. Strain P1T (= DSM 12642T = ATCC 700811T) is therefore proposed as Desulfomusa hansenii gen. nov., sp. nov. Strain p1T thus illustrates the difficulty of extrapolating rRNA similarities to physiology and/or ecological function.

  16. Status on Science and Application of Thermophilic Anaerobic Digestion

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær

    1994-01-01

    Thermophilic anaerobic processes are often regarded as less stable than mesophilic processes. In the paper this postulate is examined and disproved based on real operational data from of full-scale mesophilic and thermophilic biogas plants. The start-up produce for the thermophilic plants was...... for thermophilic digestion along with the implications for the methanogenic bacteria active at these temperatures....

  17. A comparison of stable-isotope probing of DNA and phospholipid fatty acids to study prokaryotic functional diversity in sulfate-reducing marine sediment enrichment slurries.

    Science.gov (United States)

    Webster, Gordon; Watt, Lynsey C; Rinna, Joachim; Fry, John C; Evershed, Richard P; Parkes, R John; Weightman, Andrew J

    2006-09-01

    Marine sediment slurries enriched for anaerobic, sulfate-reducing prokaryotic communities utilizing glucose and acetate were used to provide the first comparison between stable-isotope probing (SIP) of phospholipid fatty acids (PLFA) and DNA (16S rRNA and dsrA genes) biomarkers. Different 13C-labelled substrates (glucose, acetate and pyruvate) at low concentrations (100 microM) were used over a 7-day incubation to follow and identify carbon flow into different members of the community. Limited changes in total PLFA and bacterial 16S rRNA gene DGGE profiles over 7 days suggested the presence of a stable bacterial community. A broad range of PLFA were rapidly labelled (within 12 h) in the 13C-glucose slurry but this changed with time, suggesting the presence of an active glucose-utilizing population and later development of another population able to utilize glucose metabolites. The identity of the major glucose-utilizers was unclear as 13C-enriched PLFA were common (16:0, 16:1, 18:1omega7, highest incorporation) and there was little difference between 12C- and 13C-DNA 16S rRNA gene denaturing gradient gel electrophoresis (DGGE) profiles. Seemingly glucose, a readily utilizable substrate, resulted in widespread incorporation consistent with the higher extent of 13C-incorporation (approximately 10 times) into PLFA compared with 13C-acetate or 13C-pyruvate. 13C-PLFA in the 13C-acetate and 13C-pyruvate slurries were similar to each other and to those that developed in the 13C-glucose slurry after 4 days. These were more diagnostic, with branched odd-chain fatty acids (i15:0, a15:0 and 15:1omega6) possibly indicating the presence of Desulfococcus or Desulfosarcina sulfate-reducing bacteria (SRB) and sequences related to these SRB were in the 13C-acetate-DNA dsrA gene library. The 13C-acetate-DNA 16S rRNA gene library also contained sequences closely related to SRB, but these were the acetate-utilizing Desulfobacter sp., as well as a broad range of uncultured Bacteria. In

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

    Science.gov (United States)

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

    2001-12-01

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

  19. Caldicellulosiruptor obsidiansis sp. nov., an anaerobic, extremely thermophilic, cellulolytic bacterium isolated from Obsidian Pool, Yellowstone National Park.

    Science.gov (United States)

    Hamilton-Brehm, Scott D; Mosher, Jennifer J; Vishnivetskaya, Tatiana; Podar, Mircea; Carroll, Sue; Allman, Steve; Phelps, Tommy J; Keller, Martin; Elkins, James G

    2010-02-01

    A novel, obligately anaerobic, extremely thermophilic, cellulolytic bacterium, designated OB47(T), was isolated from Obsidian Pool, Yellowstone National Park, WY. The isolate was a nonmotile, non-spore-forming, Gram-positive rod approximately 2 microm long by 0.2 microm wide and grew at temperatures between 55 and 85 degrees C, with the optimum at 78 degrees C. The pH range for growth was 6.0 to 8.0, with values of near 7.0 being optimal. Growth on cellobiose produced the fastest specific growth rate at 0.75 h(-1). The organism also displayed fermentative growth on glucose, maltose, arabinose, fructose, starch, lactose, mannose, sucrose, galactose, xylose, arabinogalactan, Avicel, xylan, filter paper, processed cardboard, pectin, dilute acid-pretreated switchgrass, and Populus. OB47(T) was unable to grow on mannitol, fucose, lignin, Gelrite, acetate, glycerol, ribose, sorbitol, carboxymethylcellulose, and casein. Yeast extract stimulated growth, and thiosulfate, sulfate, nitrate, and sulfur were not reduced. Fermentation end products were mainly acetate, H2, and CO2, although lactate and ethanol were produced in 5-liter batch fermentations. The G+C content of the DNA was 35 mol%, and sequence analysis of the small subunit rRNA gene placed OB47(T) within the genus Caldicellulosiruptor. Based on its phylogenetic and phenotypic properties, the isolate is proposed to be designated Caldicellulosiruptor obsidiansis sp. nov. and OB47 is the type strain (ATCC BAA-2073).

  20. Caldicellulosiruptor obsidiansis sp. nov., an Anaerobic, Extremely Thermophilic, Cellulolytic Bacterium Isolated from Obsidian Pool, Yellowstone National Park▿

    Science.gov (United States)

    Hamilton-Brehm, Scott D.; Mosher, Jennifer J.; Vishnivetskaya, Tatiana; Podar, Mircea; Carroll, Sue; Allman, Steve; Phelps, Tommy J.; Keller, Martin; Elkins, James G.

    2010-01-01

    A novel, obligately anaerobic, extremely thermophilic, cellulolytic bacterium, designated OB47T, was isolated from Obsidian Pool, Yellowstone National Park, WY. The isolate was a nonmotile, non-spore-forming, Gram-positive rod approximately 2 μm long by 0.2 μm wide and grew at temperatures between 55 and 85°C, with the optimum at 78°C. The pH range for growth was 6.0 to 8.0, with values of near 7.0 being optimal. Growth on cellobiose produced the fastest specific growth rate at 0.75 h−1. The organism also displayed fermentative growth on glucose, maltose, arabinose, fructose, starch, lactose, mannose, sucrose, galactose, xylose, arabinogalactan, Avicel, xylan, filter paper, processed cardboard, pectin, dilute acid-pretreated switchgrass, and Populus. OB47T was unable to grow on mannitol, fucose, lignin, Gelrite, acetate, glycerol, ribose, sorbitol, carboxymethylcellulose, and casein. Yeast extract stimulated growth, and thiosulfate, sulfate, nitrate, and sulfur were not reduced. Fermentation end products were mainly acetate, H2, and CO2, although lactate and ethanol were produced in 5-liter batch fermentations. The G+C content of the DNA was 35 mol%, and sequence analysis of the small subunit rRNA gene placed OB47T within the genus Caldicellulosiruptor. Based on its phylogenetic and phenotypic properties, the isolate is proposed to be designated Caldicellulosiruptor obsidiansis sp. nov. and OB47 is the type strain (ATCC BAA-2073). PMID:20023107

  1. Production of thermophilic and acidophilic endoglucanases by ...

    African Journals Online (AJOL)

    Production of thermophilic and acidophilic endoglucanases by mutant Trichoderma atroviride 102C1 using agro-industrial by-products. ... The effect of the carbon (sugarcane bagasse: SCB) and nitrogen (corn steep liquor: CSL) sources on ...

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

    Directory of Open Access Journals (Sweden)

    Lilia Montoya

    2011-01-01

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

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

    Science.gov (United States)

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

    2011-01-01

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

  4. Effects of ferrous ions on the metabolism of sulfate-reducing bacteria; Ryusan`en kangenkin no taisha ni oyobosu tetsu ion no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Baba, F.; Suzuki, T. [Ajinomoto Co. Inc., Tokyo (Japan). Technology and Engineering Lab.]: Seo, M. [Hokkaido Univ., Sapporo (Japan). Graduate School

    1995-11-15

    The grave damages due to microorganisms occur occasionally to the ironic piping and the like when river water is used as industrial water. In the present researches, the effects of Fe{sup 2+} on the amount and activity of sulfate-reducing bacteria in the culture medium with the concentration of Fe{sup 2+} changed by stages from 3.6{times}10{sup -4} M to 0.7M are examined. Further, the relations between the activity of the bacteria and the amount of FeS generated in the medium are investigated as an in-site means to observe the activity of the bacteria in the medium wherein the produced S{sup 2-} is converted into FeS once it is generated. The following conclusions are drawn therefrom. In the initial medium with the Fe{sup 2+} concentration from 3.6{times}10{sup -4} M to 0.7M, the growth of the bacteria is maximum at the concentration of 1.0{times}10{sup -2}. Over this concentration the growth is weakened due to the osmotic pressure, lowering of nutriment and the deposit of waste, and the bacteria are extirpated due to the direct effect of osmotic press when the concentration is 0.7M. The total amount of FeS produced due to the bacteria is in conformity with the tendency of growth of bacteria till 30 hours of culture. 18 refs., 6 figs., 2 tabs.

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

    Science.gov (United States)

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

    2004-04-01

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

  6. Isolation and characterization of a mesophilic heavy-metals-tolerant sulfate-reducing bacterium Desulfomicrobium sp. from an enrichment culture using phosphogypsum as a sulfate source

    International Nuclear Information System (INIS)

    Azabou, Samia; Mechichi, Tahar; Patel, Bharat K.C.; Sayadi, Sami

    2007-01-01

    A sulfate-reducing bacterium, was isolated from a 6 month trained enrichment culture in an anaerobic media containing phosphogypsum as a sulfate source, and, designated strain SA2. Cells of strain SA2 were rod-shaped, did not form spores and stained Gram-negative. Phylogenetic analysis of the 16S rRNA gene sequence of the isolate revealed that it was related to members of the genus Desulfomicrobium (average sequence similarity of 98%) with Desulfomicrobium baculatum being the most closely related (sequence similarity of 99%). Strain SA2 used thiosulfate, sulfate, sulfite and elemental sulfur as electron acceptors and produced sulfide. Strain SA2 reduced sulfate contained in 1-20 g/L phosphogypsum to sulfide with reduction of sulfate contained in 2 g/L phosphogypsum being the optimum concentration. Strain SA2 grew with metalloid, halogenated and non-metal ions present in phosphogypsum and with added high concentrations of heavy metals (125 ppm Zn and 100 ppm Ni, W, Li and Al). The relative order for the inhibitory metal concentrations, based on the IC 50 values, was Cu, Te > Cd > Fe, Co, Mn > F, Se > Ni, Al, Li > Zn

  7. Impacts of human activities on distribution of sulfate-reducing prokaryotes and antibiotic resistance genes in marine coastal sediments of Hong Kong.

    Science.gov (United States)

    Guo, Feng; Li, Bing; Yang, Ying; Deng, Yu; Qiu, Jian-Wen; Li, Xiangdong; Leung, Kenneth My; Zhang, Tong

    2016-09-01

    Sulfate-reducing prokaryotes (SRPs) and antibiotic resistance genes (ARGs) in sediments could be biomarkers for evaluating the environmental impacts of human activities, although factors governing their distribution are not clear yet. By using metagenomic approach, this study investigated the distributions of SRPs and ARGs in marine sediments collected from 12 different coastal locations of Hong Kong, which exhibited different pollution levels and were classified into two groups based on sediment parameters. Our results showed that relative abundances of major SRP genera to total prokaryotes were consistently lower in the more seriously polluted sediments (P-value human impacts. Moreover, a unimodel distribution pattern for SRPs along with the pollution gradient was observed. Although total ARGs were enriched in sediments from the polluted sites, distribution of single major ARG types could be explained neither by individual sediment parameters nor by corresponding concentration of antibiotics. It supports the hypothesis that the persistence of ARGs in sediments may not need the selection of antibiotics. In summary, our study provided important hints of the niche differentiation of SRPs and behavior of ARGs in marine coastal sediment. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Effects of bacterially produced precipitates on the metabolism of sulfate reducing bacteria during the bio-treatment process of copper-containing wastewater

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A large volume of bacterially produced precipitates are generated during the bio-treatment of heavy metal wastewater.The composition of the bacterially produced precipitates and its effects on sulfate reducing bacteria (SRB) in copper-containing waste stream were evaluated in this study.The elemental composition of the microbial precipitate was studied using electrodispersive X-ray spectroscopy (EDX),and it was found that the ratio of S:Cu was 1.12.Combining with the results of copper distribution in the SRB metabolism culture,which was analyzed by the sequential extraction procedure,copper in the precipitates was determined as covellite (CuS).The bacterially produced precipitates caused a decrease of the sulfate reduction rate,and the more precipitates were generated,the lower the sulfate reduction rate was.The particle sizes of bacterially generated covellite were ranging from 0.03 to 2 m by particles size distribution (PSD) analysis,which was smaller than that of the SRB cells.Transmission electron microscopy (TEM) analysis showed that the microbial covellite was deposited on the surface of the cell.The effects of the microbial precipitate on SRB metabolism were found to be weakened by increasing the precipitation time and adding microbial polymeric substances in later experiments.These results provided direct evidence that the SRB activity was inhibited by the bacterially produced covellite,which enveloped the bacterium and thus affected the metabolism of SRB on mass transfer.

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

    Science.gov (United States)

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

    2013-08-10

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

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

    Science.gov (United States)

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

    2016-05-01

    Sulfate-reducing bacteria (SRB) are widely existed in oil production system, and its H2S product inhibits rhamnolipid producing bacteria. In-situ production of rhamnolipid is promising for microbial enhanced oil recovery. Inhibition of SRB, removal of H2S and production of rhamnolipid by recombinant Pseudomonas stutzeri Rhl were investigated. Strain Rhl can simultaneously remove S(2-) (>92%) and produce rhamnolipid (>136mg/l) under S(2-) stress below 33.3mg/l. Rhl reduced the SRB numbers from 10(9) to 10(5)cells/ml, and the production of H2S was delayed and decreased to below 2mg/l. Rhl also produced rhamnolipid and removed S(2-) under laboratory simulated oil reservoir conditions. High-throughput sequencing data demonstrated that addition of strain Rhl significantly changed the original microbial communities of oilfield production water and decreased the species and abundance of SRB. Bioaugmentation of strain Rhl in oilfield is promising for simultaneous control of SRB, removal of S(2-) and enhance oil recovery. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Biocorrosion of carbon steel alloys by an hydrogenotrophic sulfate-reducing bacterium Desulfovibrio capillatus isolated from a Mexican oil field separator

    Energy Technology Data Exchange (ETDEWEB)

    Miranda, E. [IRD, Institut de Recherche pour le Developement, Universites de Provence et de la Mediterranee, ESIL Case 925, 163 Avenue de Luminy, F-13288 Marseille, Cedex 09 (France); Bethencourt, M. [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica y Quimica Inorganica, CASEM, Universidad de Cadiz, Poligono Rio San Pedro s/n, 11510 Puerto Real (Spain)]. E-mail: manuel.bethencourt@uca.es; Botana, F.J. [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica y Quimica Inorganica, CASEM, Universidad de Cadiz, Poligono Rio San Pedro s/n, 11510 Puerto Real (Spain); Cano, M.J. [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica y Quimica Inorganica, CASEM, Universidad de Cadiz, Poligono Rio San Pedro s/n, 11510 Puerto Real (Spain); Sanchez-Amaya, J.M. [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica y Quimica Inorganica, CASEM, Universidad de Cadiz, Poligono Rio San Pedro s/n, 11510 Puerto Real (Spain); Corzo, A. [Departamento de Biologia, CASEM, Universidad de Cadiz, Poligono Rio San Pedro s/n, 11510 Puerto Real (Spain); Garcia de Lomas, J. [Departamento de Biologia, CASEM, Universidad de Cadiz, Poligono Rio San Pedro s/n, 11510 Puerto Real (Spain); Fardeau, M.L. [IRD, Institut de Recherche pour le Developement, Universites de Provence et de la Mediterranee, ESIL Case 925, 163 Avenue de Luminy, F-13288 Marseille, Cedex 09 (France); Ollivier, B. [IRD, Institut de Recherche pour le Developement, Universites de Provence et de la Mediterranee, ESIL Case 925, 163 Avenue de Luminy, F-13288 Marseille, Cedex 09 (France)

    2006-09-15

    The hydrogenotrophic sulfate-reducing bacterium (SRB) Desulfovibrio capillatus (DSM14982{sup T}) was isolated from an oil field separator with serious corrosion problems; this is the study of its role in the corrosion of carbon steels under anaerobic conditions. Immersion tests with two steel alloys, St-35.8 (typical carbon steel employed in European naval industry), and API-5XL52 (weathering alloy steel employed in Mexican oil industries) were performed. Total exposure was 45 days and different concentrations of thiosulfate as electron acceptor for bacterial growth were employed. The samples immersed in media with SRB undergo fast activation and numerous active sites form on the surface. Microscopic observations were made by environmental scanning electron microscopy (ESEM). Weight loss and electrochemical testing included open circuit potential (E {sub corr}), polarization resistance (R {sub p}), electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) were measured with and without bacteria in the culture medium in order to determine corrosion rates and mechanisms. All electrochemical techniques have shown that after the end of the exponential phase the corrosion activity notably increased due to the high concentration of bacterial metabolites. Finally, the corrosion behavior of API-5XL52 was worse than St-35.8.

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

    Science.gov (United States)

    2013-01-01

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

  13. Bioassessment of heavy metal toxicity and enhancement of heavy metal removal by sulfate-reducing bacteria in the presence of zero valent iron.

    Science.gov (United States)

    Guo, Jing; Kang, Yong; Feng, Ying

    2017-12-01

    A simple and valid toxicity evaluation of Zn 2+ , Mn 2+ and Cr 6+ on sulfate-reducing bacteria (SRB) and heavy metal removal were investigated using the SRB system and SRB+Fe 0 system. The heavy metal toxicity coefficient (β) and the heavy metal concentration resulting in 50% inhibition of sulfate reduction (I) from a modeling process were proposed to evaluate the heavy metal toxicity and nonlinear regression was applied to search for evaluation indices β and I. The heavy metal toxicity order was Cr 6+  > Mn 2+  > Zn 2+ . Compared with the SRB system, the SRB+Fe 0 system exhibited a better capability for sulfate reduction and heavy metal removal. The heavy metal removal was above 99% in the SRB+Fe 0 system, except for Mn 2+ . The energy-dispersive spectroscopy (EDS) analysis showed that the precipitates were removed primarily as sulfide for Zn 2+ and hydroxide for Mn 2+ and Cr 6+ .The method of evaluating the heavy metal toxicity on SRB was of great significance to understand the fundamentals of the heavy metal toxicity and inhibition effects on the microorganism and regulate the process of microbial sulfate reduction. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Biocorrosion of carbon steel alloys by an hydrogenotrophic sulfate-reducing bacterium Desulfovibrio capillatus isolated from a Mexican oil field separator

    International Nuclear Information System (INIS)

    Miranda, E.; Bethencourt, M.; Botana, F.J.; Cano, M.J.; Sanchez-Amaya, J.M.; Corzo, A.; Garcia de Lomas, J.; Fardeau, M.L.; Ollivier, B.

    2006-01-01

    The hydrogenotrophic sulfate-reducing bacterium (SRB) Desulfovibrio capillatus (DSM14982 T ) was isolated from an oil field separator with serious corrosion problems; this is the study of its role in the corrosion of carbon steels under anaerobic conditions. Immersion tests with two steel alloys, St-35.8 (typical carbon steel employed in European naval industry), and API-5XL52 (weathering alloy steel employed in Mexican oil industries) were performed. Total exposure was 45 days and different concentrations of thiosulfate as electron acceptor for bacterial growth were employed. The samples immersed in media with SRB undergo fast activation and numerous active sites form on the surface. Microscopic observations were made by environmental scanning electron microscopy (ESEM). Weight loss and electrochemical testing included open circuit potential (E corr ), polarization resistance (R p ), electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) were measured with and without bacteria in the culture medium in order to determine corrosion rates and mechanisms. All electrochemical techniques have shown that after the end of the exponential phase the corrosion activity notably increased due to the high concentration of bacterial metabolites. Finally, the corrosion behavior of API-5XL52 was worse than St-35.8

  15. Degradation of phenol via phenylphosphate and carboxylation to 4-hydroxybenzoate by a newly isolated strain of the sulfate-reducing bacterium Desulfobacterium anilini.

    Science.gov (United States)

    Ahn, Young-Beom; Chae, Jong-Chan; Zylstra, Gerben J; Häggblom, Max M

    2009-07-01

    A sulfate-reducing phenol-degrading bacterium, strain AK1, was isolated from a 2-bromophenol-utilizing sulfidogenic estuarine sediment enrichment culture. On the basis of phylogenetic analysis of the 16S rRNA gene and DNA homology, strain AK1 is most closely related to Desulfobacterium anilini strain Ani1 (= DSM 4660(T)). In addition to phenol, this organism degrades a variety of other aromatic compounds, including benzoate, 2-hydroxybenzoate, 4-hydroxybenzoate, 4-hydroxyphenylacetate, 2-aminobenzoate, 2-fluorophenol, and 2-fluorobenzoate, but it does not degrade aniline, 3-hydroxybenzoate, 4-cyanophenol, 2,4-dihydroxybenzoate, monohalogenated phenols, or monohalogenated benzoates. Growth with sulfate as an electron acceptor occurred with acetate and pyruvate but not with citrate, propionate, butyrate, lactate, glucose, or succinate. Strain AK1 is able to use sulfate, sulfite, and thiosulfate as electron acceptors. A putative phenylphosphate synthase gene responsible for anaerobic phenol degradation was identified in strain AK1. In phenol-grown cultures inducible expression of the ppsA gene was verified by reverse transcriptase PCR, and 4-hydroxybenzoate was detected as an intermediate. These results suggest that the pathway for anaerobic degradation of phenol in D. anilini strain AK1 proceeds via phosphorylation of phenol to phenylphosphate, followed by carboxylation to 4-hydroxybenzoate. The details concerning such reaction pathways in sulfidogenic bacteria have not been characterized previously.

  16. Thermophilic Fungi: Their Physiology and Enzymes†

    OpenAIRE

    Maheshwari, Ramesh; Bharadwaj, Girish; Bhat, Mahalingeshwara K.

    2000-01-01

    Thermophilic fungi are a small assemblage in mycota that have a minimum temperature of growth at or above 20 degrees C and a maximum temperature of growth extending Itp to 60 to 62 degrees C. As the only representatives of eukaryotic organisms that can grow at temperatures above 45 degrees C, the thermophilic fungi are valuable experimental systems for investigations of mechanisms that allow growth at moderately high temperature yet limit their growth beyond 60 to 62 degrees C. Although wides...

  17. Industrial relevance of thermophilic Archaea.

    Science.gov (United States)

    Egorova, Ksenia; Antranikian, Garabed

    2005-12-01

    The dramatic increase of newly isolated extremophilic microorganisms, analysis of their genomes and investigations of their enzymes by academic and industrial laboratories demonstrate the great potential of extremophiles in industrial (white) biotechnology. Enzymes derived from extremophiles (extremozymes) are superior to the traditional catalysts because they can perform industrial processes even under harsh conditions, under which conventional proteins are completely denatured. In particular, enzymes from thermophilic and hyperthermophilic Archaea have industrial relevance. Despite intensive investigations, our knowledge of the structure-function relationships of their enzymes is still limited. Information concerning the molecular properties of their enzymes and genes has to be obtained to be able to understand the mechanisms that are responsible for catalytic activity and stability at the boiling point of water.

  18. Brockia lithotrophica gen. nov., sp. nov., an anaerobic thermophilic bacterium from a terrestrial hot spring.

    Science.gov (United States)

    Perevalova, Anna A; Kublanov, Ilya V; Baslerov, R V; Zhang, Gengxin; Bonch-Osmolovskaya, Elizaveta A

    2013-02-01

    A novel thermophilic bacterium, strain Kam1851(T), was isolated from a terrestrial hot spring of the Uzon Caldera, Kamchatka Peninsula, Russia. Cells of strain Kam1851(T) were spore-forming rods with a gram-positive type of cell wall. Growth was observed between 46 and 78 °C, and pH 5.5-8.5. The optimal growth (doubling time, 6.0 h) was at 60-65 °C and pH 6.5. The isolate was an obligate anaerobe growing in pre-reduced medium only. It grew on mineral medium with molecular hydrogen or formate as electron donors, and elemental sulfur, thiosulfate or polysulfide as electron acceptors. The main cellular fatty acids were C(16 : 0) (34.2 %), iso-C(16 : 0) (18 %), C(18 : 0) (12.8 %) and iso-C(17 : 0) (11.1 %). The G+C content of the genomic DNA of strain Kam1851(T) was 63 mol%. 16S rRNA gene sequence analysis showed that strain Kam1851(T) belonged to the order Thermoanaerobacterales, but it was not closely related to representatives of any genera with validly published names. The most closely related strains, which had no more than 89.2 % sequence similarity, were members of the genera Ammonifex and Caldanaerobacter. On the basis of its phylogenetic position and novel phenotypic features, isolate Kam1851(T) is proposed to represent a novel species in a new genus, Brockia lithotrophica gen. nov., sp. nov.; the type strain of Brockia lithotrophica is Kam1851(T) ( = DSM 22653(T) = VKM B-2685(T)).

  19. Thermophilic Fungi: Their Physiology and Enzymes†

    Science.gov (United States)

    Maheshwari, Ramesh; Bharadwaj, Girish; Bhat, Mahalingeshwara K.

    2000-01-01

    Thermophilic fungi are a small assemblage in mycota that have a minimum temperature of growth at or above 20°C and a maximum temperature of growth extending up to 60 to 62°C. As the only representatives of eukaryotic organisms that can grow at temperatures above 45°C, the thermophilic fungi are valuable experimental systems for investigations of mechanisms that allow growth at moderately high temperature yet limit their growth beyond 60 to 62°C. Although widespread in terrestrial habitats, they have remained underexplored compared to thermophilic species of eubacteria and archaea. However, thermophilic fungi are potential sources of enzymes with scientific and commercial interests. This review, for the first time, compiles information on the physiology and enzymes of thermophilic fungi. Thermophilic fungi can be grown in minimal media with metabolic rates and growth yields comparable to those of mesophilic fungi. Studies of their growth kinetics, respiration, mixed-substrate utilization, nutrient uptake, and protein breakdown rate have provided some basic information not only on thermophilic fungi but also on filamentous fungi in general. Some species have the ability to grow at ambient temperatures if cultures are initiated with germinated spores or mycelial inoculum or if a nutritionally rich medium is used. Thermophilic fungi have a powerful ability to degrade polysaccharide constituents of biomass. The properties of their enzymes show differences not only among species but also among strains of the same species. Their extracellular enzymes display temperature optima for activity that are close to or above the optimum temperature for the growth of organism and, in general, are more heat stable than those of the mesophilic fungi. Some extracellular enzymes from thermophilic fungi are being produced commercially, and a few others have commercial prospects. Genes of thermophilic fungi encoding lipase, protease, xylanase, and cellulase have been cloned and

  20. Thermophillic Sidestream Anaerobic Membrane Bioreactors: The Shear Rate Dilemma

    NARCIS (Netherlands)

    Jeison, D.A.; Telkamp, P.; Lier, van J.B.

    2009-01-01

    Anaerobic biomass retention under thermophilic conditions has proven difficult. Membrane filtration can be used as alternative way to achieve high sludge concentrations. This research studied the feasibility of anaerobic membrane bioreactors (AnMBRs) under thermophilic conditions. A sidestream MBR

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jiemin [National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, P.O. Box 353, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhou, Xuemei; Li, Yuguang [101 Institute, Ministry of Civil Affairs, Beijing 100070 (China); Xing, Jianmin, E-mail: jmxing@ipe.ac.cn [National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, P.O. Box 353, Beijing 100190 (China)

    2015-09-15

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

  2. Removal of Arsenic Using Acid/Metal-Tolerant Sulfate Reducing Bacteria: A New Approach for Bioremediation of High-Arsenic Acid Mine Waters

    Directory of Open Access Journals (Sweden)

    Jennyfer Serrano

    2017-12-01

    Full Text Available Fluvial sediments, soils, and natural waters in northern Chile are characterized by high arsenic (As content. Mining operations in this area are potential sources of As and other metal contaminants, due to acid mine drainage (AMD generation. Sulfate Reducing Bacteria (SRB has been used for the treatment of AMD, as they allow for the reduction of sulfate, the generation of alkalinity, and the removal of dissolved heavy metals and metalloids by precipitation as insoluble metal sulfides. Thus, SRB could be used to remove As and other heavy metals from AMD, however the tolerance of SRB to high metal concentrations and low pH is limited. The present study aimed to quantify the impact of SRB in As removal under acidic and As-Fe-rich conditions. Our results show that SRB tolerate low pH (up to 3.5 and high concentrations of As (~3.6 mg·L−1. Batch experiments showed As removal of up to 73%, Iron (Fe removal higher than 78% and a neutralization of pH from acidic to circum-neutral conditions (pH 6–8. In addition, XRD analysis showed the dominance of amorphous minerals, while Scanning Electron Microscopy/Energy Dispersive X-ray Spectroscopy (SEM-EDX analysis showed associations between As, Fe, and sulfur, indicating the presence of Fe-S-As compounds or interaction of As species with amorphous and/or nanocrystalline phases by sorption processes. These results indicate that the As removal was mediated by acid/metal-tolerant SRB and open the potential for the application of new strains of acid/metal-tolerant SRB for the remediation of high-As acid mine waters.

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

    Directory of Open Access Journals (Sweden)

    Yu-Chen eLing

    2015-07-01

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

  4. Characterization of the marine propionate-degrading, sulfate-reducing bacterium Desulfofaba fastidiosa sp. nov. and reclassification of Desulfomusa hansenii as Desulfofaba hansenii comb. nov.

    Science.gov (United States)

    Abildgaard, Lone; Ramsing, Niels Birger; Finster, Kai

    2004-03-01

    A rod-shaped, slightly curved sulfate reducer, designated strain P2(T), was isolated from the sulfate-methane transition zone of a marine sediment. Cells were motile by means of a single polar flagellum. The strain reduced sulfate, thiosulfate and sulfite to sulfide and used propionate, lactate and 1-propanol as electron donors. Strain P2(T) also grew by fermentation of lactate. Propionate was oxidized incompletely to acetate and CO(2). The DNA G+C content was 48.8 mol%. Sequence analysis of the small-subunit rDNA and the dissimilatory sulfite reductase gene revealed that strain P2(T) was related to the genera Desulfonema, Desulfococcus, Desulfosarcina, 'Desulfobotulus', Desulfofaba, Desulfomusa and Desulfofrigus. These genera include incomplete as well as complete oxidizers of substrates. Strain P2(T) shared important morphological and physiological traits with Desulfofaba gelida and Desulfomusa hansenii, including the ability to oxidize propionate incompletely to acetate. The 16S rRNA gene similarities of P2(T) to Desulfofaba gelida and Desulfomusa hansenii were respectively 92.9 and 91.5 %. Combining phenotypic and genotypic traits, we propose strain P2(T) to be a member of the genus Desulfofaba. The name Desulfofaba fastidiosa sp. nov. (type strain P2(T)=DSM 15249(T)=ATCC BAA-815(T)) is proposed, reflecting the limited number of substrates consumed by the strain. In addition, the reclassification of Desulfomusa hansenii as a member of the genus Desulfofaba, Desulfofaba hansenii comb. nov., is proposed. A common line of descent and a number of shared phenotypic traits support this reclassification.

  5. Spatio-temporal dynamics of sulfate-reducing bacteria in extreme environment of Rogoznica Lake revealed by 16S rRNA analysis

    Science.gov (United States)

    Čanković, Milan; Petrić, Ines; Marguš, Marija; Ciglenečki, Irena

    2017-08-01

    Highly eutrophic and euxinic seawater system of Rogoznica Lake (Croatia) was used as a study site for investigation of distribution, diversity and abundance of sulfate-reducing bacteria (SRB) during stratified conditions in the summer and winter season, by targeting 6 phylogenetic subgroups of SRB. 16S rRNA gene sequences indicated that community cannot be directly related to cultured SRB species but rather that Rogoznica Lake harbors habitat-specific SRB populations associated to bacteria belonging to δ-Proteobacteria with few Firmicutes and Verrucomicrobium-related populations. Clear spatial-temporal shifts in the SRB community structure were observed. Results implied existence of distinct SRB populations between the water column and sediment, as well as higher diversity of the SRB occupying water layer then the ones found in the sediment. Likewise, seasonal variations in populations were observed. While SRB community was more diverse in the winter compared to the summer season in the water layer, situation was opposite in the sediment. Water layer communities seem to be more susceptible to changes of physico-chemical parameters, while those in the sediment have prorogated response to these changes. Results indicate that SRB diversity is still highly underestimated in natural environments, especially in specific habitats such as Rogoznica Lake. Presented data show a complex SRB diversity and distribution supporting the idea that habitat-specific SRB communities are important part of the anaerobic food chain in degradation of organic matter as well as cycling of sulfur and carbon species in the Lake and similar anoxic environment.

  6. Effects of continuous addition of nitrate to a thermophilic anaerobic digestion system

    International Nuclear Information System (INIS)

    Rivard, C.J.

    1983-01-01

    The biodegradation of complex organic matter is regulated partially by the ability to dump electrons which build up in the form of reduced nicotinamide adenine dinucleotide (NAD). The effects of the continuous addition of the oxidant, nitrate, were investigated on a single-stage, thermophilic, anaerobic digester. The digester acclimated rapidly to nitrate addition. The continuous addition of nitrate resulted in a constant inhibition of total gas (30%) and methane production (36%). Reduction in total gas and methane production was accompanied by increases in sludge pH and acetate, propionate, and ammonium ion pools. Effluent particle size distribution revealed a shift to smaller particle sizes in the nitrate-pumped sludge. The continuous addition of nitrate resulted in lower numbers of methanogens and sulfate reducers in the sludge, with increases in nitrate-reducing and cellulose-degrading microorganisms. These findings indicate that added nitrate underwent dissimilatory reduction to ammonium ion, as determined from gas analysis, ammonium pools, and 15 N-nitrate-label experiments. Continuous nitrate addition to a single-phase digestion system was determined to inhibit methane production from biomass and wastes. Thus for the single-stage digestion system in which maximum methane production is desired, the addition of nitrate is not recommended. However, in a multistage digestion system, the continuous addition of nitrate in the primary stage to increase the rate and extent of degradation of organic matter to volatile fatty acids, which then would serve as feed to a second stage, may be advantageous

  7. Hexavalent uranium reduction from solid phase by thermophilic bacterium Thermoterrabacterium ferrireducens

    International Nuclear Information System (INIS)

    Khijniak, T.V.; Slobodkin, A.I.; Bonch-Osmolovskaya, E.A.; Medvedeva-Lyalikova, N.N.; Coker, V.; Lloyd, J.R.; Birkeland, N.K.

    2005-01-01

    Full text of publication follows: It has been reported that in uranium-contaminated sites, solid-phase U(VI) present in sediments is resistant to microbial reduction. Also, it was demonstrated that mesophilic iron and sulfate-reducing bacteria can reduce hexavalent uranium and sulphate-reducing bacteria were able to grow via uranium reduction. Among thermophilic microorganisms reduction of hexavalent uranium has been demonstrated only for cell suspensions of two genera: Pyrobaculum and Thermus. In the present study, Thermoterrabacterium ferrireducens was tested for reduction of U(VI), a thermophilic, gram-positive anaerobic bacterium capable for growth with the reduction of various electron acceptors including Fe(III). Kinetic of bacterial growth, uranium reduction and influence of different uranium concentrations were investigated at 65 deg. C. Due to presence of phosphate in the basal medium yellow uranium phosphate precipitate was formed after addition of uranyl acetate. After 68 h of incubation control tubes without bacteria were contained yellow precipitate whereas in presence of bacteria precipitate turned to the grey color. In the control tubes uranium phosphates and other elements formed a uniform mixture of crystals, but in presence of bacteria the round shape particles, containing uranium, were found by Environmental Scan Electron Microscopy of air-dried or frozen samples. To determine valent state speciation spectroscopic investigations were performed also. Initial yellow uranium phosphate precipitate was separated and identified as uramphite - (NH 4 )(UO 2 )(PO 4 )*3H 2 O by X-Ray Powder Diffraction. Grey precipitate, which was formed by bacterial reduction, was identified as ningyoite - CaU(PO 4 ) 2 *H 2 O. The fact that final grey precipitate contain U(IV) was also confirmed by EXAFS investigation. High concentration of uranium has toxic effect. 1 and 2.5 mM of uranium (VI) support bacterial growth and bacterial biomass was accumulated, but if 5 or 10

  8. Bioprospecting thermophiles for cellulase production: a review.

    Science.gov (United States)

    Acharya, Somen; Chaudhary, Anita

    2012-07-01

    Most of the potential bioprospecting is currently related to the study of the extremophiles and their potential use in industrial processes. Recently microbial cellulases find applications in various industries and constitute a major group of industrial enzymes. Considerable amount of work has been done on microbial cellulases, especially with resurgence of interest in biomass ethanol production employing cellulases and use of cellulases in textile and paper industry. Most efficient method of lignocellulosic biomass hydrolysis is through enzymatic saccharification using cellulases. Significant information has also been gained about the physiology of thermophilic cellulases producers and process development for enzyme production and biomass saccharification. The review discusses the current knowledge on cellulase producing thermophilic microorganisms, their physiological adaptations and control of cellulase gene expression. It discusses the industrial applications of thermophilic cellulases, their cost of production and challenges in cellulase research especially in the area of improving process economics of enzyme production.

  9. Bioprospecting thermophiles for cellulase production: a review

    Directory of Open Access Journals (Sweden)

    Somen Acharya

    2012-09-01

    Full Text Available Most of the potential bioprospecting is currently related to the study of the extremophiles and their potential use in industrial processes. Recently microbial cellulases find applications in various industries and constitute a major group of industrial enzymes. Considerable amount of work has been done on microbial cellulases, especially with resurgence of interest in biomass ethanol production employing cellulases and use of cellulases in textile and paper industry. Most efficient method of lignocellulosic biomass hydrolysis is through enzymatic saccharification using cellulases. Significant information has also been gained about the physiology of thermophilic cellulases producers and process development for enzyme production and biomass saccharification. The review discusses the current knowledge on cellulase producing thermophilic microorganisms, their physiological adaptations and control of cellulase gene expression. It discusses the industrial applications of thermophilic cellulases, their cost of production and challenges in cellulase research especially in the area of improving process economics of enzyme production.

  10. Heavy metal speciation in solid-phase materials from a bacterial sulfate reducing bioreactor using sequential extraction procedure combined with acid volatile sulfide analysis.

    Science.gov (United States)

    Jong, Tony; Parry, David L

    2004-04-01

    Heavy metal mobility, bioavailability and toxicity depends largely on the chemical form of metals and ultimately determines potential for environmental pollution. For this reason, determining the chemical form of heavy metals and metalloids, immobilized in sludges by biological mediated sulfate reduction, is important to evaluate their mobility and bioavailability. A modified Tessier sequential extraction procedure (SEP), complemented with acid volatile sulfide (AVS) and simultaneous extracted metals (SEM) measurements, were applied to determine the partitioning of five heavy metals (defined as Fe, Ni, Zn and Cu, and the metalloid As) in anoxic solid-phase material (ASM) from an anaerobic, sulfate reducing bioreactor into six operationally defined fractions. These fractions were water soluble, exchangeable, bound to carbonates (acid soluble), bound to Fe-Mn oxides (reducible), bound to organic matter and sulfides (oxidizable) and residual. It was found that the distribution of Fe, Ni, Zn, Cu and As in ASM was strongly influenced by its association with the above solid fractions. The fraction corresponding to organic matter and sulfides appeared to be the most important scavenging phases of As, Fe, Ni, Zn and Cu in ASM (59.8-86.7%). This result was supported by AVS and SEM (Sigma Zn, Ni and Cu) measurements, which indicated that the heavy metals existed overwhelmingly as sulfides in the organic matter and sulfide fraction. A substantial amount of Fe and Ni at 16.4 and 20.1%, respectively, were also present in the carbonate fraction, while an appreciable portion of As (18.3%) and Zn (19.4%) was bound to Fe-Mn oxides. A significant amount of heavy metals was also associated with the residual fraction, ranging from 2.1% for Zn to 18.8% for As. Based on the average total extractable heavy metal (TEHM) values, the concentration of heavy metals in the ASM was in the order of Cu > Ni > Zn > Fe > As. If the mobility and bioavailability of heavy metals are assumed to be

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

    Directory of Open Access Journals (Sweden)

    Elizabeth Trembath-Reichert

    2016-04-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

  13. Implications from distinct sulfate-reducing bacteria populations between cattle manure and digestate in the elucidation of H2S production during anaerobic digestion of animal slurry.

    Science.gov (United States)

    St-Pierre, Benoit; Wright, André-Denis G

    2017-07-01

    Biogas produced from the anaerobic digestion of animal slurry consists mainly of methane (CH 4 ) and carbon dioxide (CO 2 ), but also includes other minor gases, such as hydrogen sulfide (H 2 S). Since it can act as a potent corrosive agent and presents a health hazard even at low concentrations, H 2 S is considered an undesirable by-product of anaerobic digestion. Sulfate-reducing bacteria (SRBs) have been identified as the main biological source of H 2 S in a number of natural, biological, and human-made habitats, and thus represent likely candidate microorganisms responsible for the production of H 2 S in anaerobic manure digesters. Phylogenetically, SRBs form a divergent group of bacteria that share a common anaerobic respiration pathway that allows them to use sulfate as a terminal electron acceptor. While the composition and activity of SRBs have been well documented in other environments, their metabolic potential remains largely uncharacterized and their populations poorly defined in anaerobic manure digesters. In this context, a combination of in vitro culture-based studies and DNA-based approaches, respectively, were used to gain further insight. Unexpectedly, only low to nondetectable levels of H 2 S were produced by digestate collected from a manure biogas plant documented to have persistently high concentrations of H 2 S in its biogas (2000-3000 ppm). In contrast, combining digestate with untreated manure (a substrate with comparatively lower sulfate and SRB cell densities than digestate) was found to produce elevated H 2 S levels in culture. While a 16S rRNA gene-based community composition approach did not reveal likely candidate SRBs in digestate or untreated manure, the use of the dsrAB gene as a phylogenetic marker provided more insight. In digestate, the predominant SRBs were found to be uncharacterized species likely belonging to the genus Desulfosporosinus (Peptococcaceae, Clostridiales, Firmicutes), while Desulfovibrio-related SRBs

  14. Impact of elevated CO_2 concentrations on carbonate mineral precipitation ability of sulfate-reducing bacteria and implications for CO_2 sequestration

    International Nuclear Information System (INIS)

    Paul, Varun G.; Wronkiewicz, David J.; Mormile, Melanie R.

    2017-01-01

    Interest in anthropogenic CO_2 release and associated global climatic change has prompted numerous laboratory-scale and commercial efforts focused on capturing, sequestering or utilizing CO_2 in the subsurface. Known carbonate mineral precipitating microorganisms, such as the anaerobic sulfate-reducing bacteria (SRB), could enhance the rate of conversion of CO_2 into solid minerals and thereby improve long-term storage of captured gasses. The ability of SRB to induce carbonate mineral precipitation, when exposed to atmospheric and elevated pCO_2, was investigated in laboratory scale tests with bacteria from organic-rich sediments collected from hypersaline Lake Estancia, New Mexico. The enriched SRB culture was inoculated in continuous gas flow and batch reactors under variable headspace pCO_2 (0.0059 psi to 20 psi). Solution pH, redox conditions, sulfide, calcium and magnesium concentrations were monitored in the reactors. Those reactors containing SRB that were exposed to pCO_2 of 14.7 psi or less showed Mg-calcite precipitation. Reactors exposed to 20 psi pCO_2 did not exhibit any carbonate mineralization, likely due to the inhibition of bacterial metabolism caused by the high levels of CO_2. Hydrogen, lactate and formate served as suitable electron donors for the SRB metabolism and related carbonate mineralization. Carbon isotopic studies confirmed that ∼53% of carbon in the precipitated carbonate minerals was derived from the CO_2 headspace, with the remaining carbon being derived from the organic electron donors, and the bicarbonate ions available in the liquid medium. The ability of halotolerant SRB to induce the precipitation of carbonate minerals can potentially be applied to the long-term storage of anthropogenic CO_2 in saline aquifers and other ideal subsurface rock units by converting the gas into solid immobile phases. - Highlights: • SRB under study are capable of precipitating calcite up to 14.7 psi pCO_2. • At 20 psi pCO_2, bacterial activity

  15. Potential of nitrate addition to control the activity of sulfate-reducing prokaryotes in high-temperature oil production systems - a comparative study on a nitrate-treated and an untreated system

    DEFF Research Database (Denmark)

    Gittel, Antje; Sørensen, Ketil; Skovhus, Torben L.

    Sulfate-reducing prokaryotes (SRP) cause severe problems like microbial corrosion and reservoir souring in seawater-injected oil production systems. Adding nitrate to the injection water is applied to control SRP activity by favoring the growth of heterotrophic, nitrate-reducing bacteria (h......NRB) and nitrate-reducing, sulfide-oxidizing bacteria (NR-SOB). Microbial diversity, abundance of Bacteria, Archaea and sulfate-reducing prokaryotes (SRP) and the potential activity of SRP were studied in production water samples from a nitrate-treated and an untreated system. The reservoirs and the produced water......) and Desulfotomaculum (system with nitrate). In samples from the untreated site, the presence of active SRP was supported by demonstrating their activity (incubations with 35S-sulfate) and growth in batch cultures at pipeline temperature. No SRP activity was detected at reservoir temperature and in samples from...

  16. Characterization of 16S rRNA genes from oil field microbial communities indicates the presence of a variety of sulfate-reducing, fermentative, and sulfide-oxidizing bacteria.

    OpenAIRE

    Voordouw, G; Armstrong, S M; Reimer, M F; Fouts, B; Telang, A J; Shen, Y; Gevertz, D

    1996-01-01

    Oil field bacteria were characterized by cloning and sequencing of PCR-amplified 16S rRNA genes. A variety of gram-negative, sulfate-reducing bacteria was detected (16 members of the family Desulfovibrionaceae and 8 members of the family Desulfobacteriaceae). In contrast, a much more limited number of anaerobic, fermentative, or acetogenic bacteria was found (one Clostridium sp., one Eubacterium sp., and one Synergistes sp.). Potential sulfide oxidizers and/or microaerophiles (Thiomicrospira,...

  17. Molecular characterization of thermophilic Campylobacter species ...

    African Journals Online (AJOL)

    We identified two species of thermophilic Campylobacter in companion dogs in Jos. Majority of C. jejuni were isolated from mucoid faeces while mixed infections of the two species were more common among diarrhoeic dogs. Pet owners should observe strict hand hygiene especially after handling dogs or their faeces to ...

  18. Thermophilic biofiltration of benzene and toluene.

    Science.gov (United States)

    Cho, Kyung-Suk; Yoo, Sun-Kyung; Ryu, Hee Wook

    2007-12-01

    In the current studies, we characterized the degradation of a hot mixture of benzene and toluene (BT) gases by a thermophilic biofilter using polyurethane as packing material and high-temperature compost as a microbial source. We also examined the effect of supplementing the biofilter with yeast extract (YE). We found that YE substantially enhanced microbial activity in the thermophilic biofilter. The degrading activity of the biofilter supplied with YE was stable during long-term operation (approximately 100 d) without accumulating excess biomass. The maximum elimination capacity (1,650 g x m(-3) h(-1)) in the biofilter supplemented with YE was 3.5 times higher than that in the biofilter without YE (470 g g x m(-3) h(-1)). At similar retention times, the capacity to eliminate BT for the YE-supplemented biofilter was higher than for previously reported mesophilic biofilters. Thus, thermophilic biofiltration can be used to degrade hydrophobic compounds such as a BT mixture. Finally, 16S rDNA polymerase chain reaction-DGGE (PCR-DGGE) fingerprinting revealed that the thermophilic bacteria in the biofilter included Rubrobacter sp. and Mycobacterium sp.

  19. (Hyper)thermophilic Enzymes: Production and Purification

    NARCIS (Netherlands)

    Falcicchio, P.; Levisson, M.; Kengen, S.W.M.; Koutsopoulos, S.

    2014-01-01

    The discovery of thermophilic and hyperthermophilic microorganisms, thriving at environmental temperatures near or above 100 °C, has revolutionized our ideas about the upper temperature limit at which life can exist. The characterization of (hyper)thermostable proteins has broadened our

  20. Screening of complex thermophilic microbial community and ...

    African Journals Online (AJOL)

    Screening of complex thermophilic microbial community and application during municipal solid waste aerobic composting. ... African Journal of Biotechnology ... Complex microbial community HP83 and HC181 were applied during municipal solid waste aerobic composting that was carried out in a composting reactor under ...

  1. Thermophilic, lignocellulolytic bacteria for ethanol production: current state and perspectives

    DEFF Research Database (Denmark)

    Chang, Tinghong; Yao, Shuo

    2011-01-01

    of cellulolytic and saccharolytic thermophilic bacteria for lignocellulosic ethanol production because of their unique properties. First of all, thermophilic bacteria possess unique cellulolytic and hemicellulolytic systems and are considered as potential sources of highly active and thermostable enzymes...... for efficient biomass hydrolysis. Secondly, thermophilic bacteria ferment a broad range of carbohydrates into ethanol, and some of them display potential for ethanologenic fermentation at high yield. Thirdly, the establishment of the genetic tools for thermophilic bacteria has allowed metabolic engineering......, in particular with emphasis on improving ethanol yield, and this facilitates their employment for ethanol production. Finally, different processes for second-generation ethanol production based on thermophilic bacteria have been proposed with the aim to achieve cost-competitive processes. However, thermophilic...

  2. Investigation of isotopic and biomolecular approaches as new bio-indicators for long term natural attenuation of monoaromatic compounds in deep terrestrial aquifers by gram-positive sporulated sulfate-reducing bacteria of the genus Desulfotomaculum.

    Directory of Open Access Journals (Sweden)

    Thomas eAüllo

    2016-02-01

    Full Text Available Deep subsurface aquifers despite difficult access, represent important water resources and, at the same time, are key locations for subsurface engineering activities for the oil and gas industries, geothermal energy and CO2 or energy storage. Formation water originating from a 760 meter-deep geological gas storage aquifer was sampled and microcosms were set up to test the biodegradation potential of BTEX by indigenous microorganisms. After a long incubation period, with several subcultures, a sulfate-reducing consortium composed of only two Desulfotomaculum populations was observed able to degrade benzene, toluene and ethylbenzene, extending the number of hydrocarbonoclastic–related species among the Desulfotomaculum genus. Furthermore, we were able to couple specific carbon and hydrogen isotopic fractionation during benzene removal and the results obtained by dual compound specific isotope analysis (εC = -2.4 ‰ ± 0.3 ‰; εH = -57 ‰ ± 0.98 ‰; AKIEC: 1.0146 ± 0.0009 and AKIEH: 1.5184 ± 0.0283 were close to those obtained previously in sulfate-reducing conditions: this finding could confirm the existence of a common enzymatic reaction involving sulfate-reducers to activate benzene anaerobically. Although we cannot assign the role of each population of Desulfotomaculum in the mono-aromatic hydrocarbon degradation, this study suggests an important role of the genus Desulfotomaculum as potential biodegrader among indigenous populations in subsurface habitats. This community represents the simplest model of benzene-degrading anaerobes originating from the deepest subterranean settings ever described. As Desulfotomaculum species are often encountered in subsurface environments, this study provides some interesting results for assessing the natural response of these specific hydrologic systems in response to BTEX contamination during remediation projects.

  3. Efficient utilization of xylanase and lipase producing thermophilic ...

    African Journals Online (AJOL)

    Efficient utilization of xylanase and lipase producing thermophilic marine actinomycetes ( Streptomyces albus and Streptomyces hygroscopicus ) in the production of ecofriendly alternative energy from waste.

  4. Cellulases from Thermophilic Fungi: Recent Insights and Biotechnological Potential

    Directory of Open Access Journals (Sweden)

    Duo-Chuan Li

    2011-01-01

    Full Text Available Thermophilic fungal cellulases are promising enzymes in protein engineering efforts aimed at optimizing industrial processes, such as biomass degradation and biofuel production. The cloning and expression in recent years of new cellulase genes from thermophilic fungi have led to a better understanding of cellulose degradation in these species. Moreover, crystal structures of thermophilic fungal cellulases are now available, providing insights into their function and stability. The present paper is focused on recent progress in cloning, expression, regulation, and structure of thermophilic fungal cellulases and the current research efforts to improve their properties for better use in biotechnological applications.

  5. Real-time PCR quantification and diversity analysis of the functional genes aprA and dsrA of sulfate-reducing bacteria in marine sediments of the Peru continental margin and the Black Sea

    OpenAIRE

    Axel eSchippers; Anna eBlazejak

    2011-01-01

    A quantitative, real-time PCR (Q-PCR) assay for the functional gene adenosine 5´-phosphosulfate reductase (aprA) of sulfate-reducing bacteria (SRB) was designed. This assay was applied together with described Q-PCR assays for dissimilatory sulfite reductase (dsrA) and the 16S rRNA gene of total Bacteria to marine sediments from the Peru margin (0 – 121 meters below seafloor (mbsf)) and the Black Sea (0 – 6 mbsf). Clone libraries of aprA show that all isolated sequences originate from SRB...

  6. Thermophilic composting of municipal solid waste

    International Nuclear Information System (INIS)

    Elango, D.; Thinakaran, N.; Panneerselvam, P.; Sivanesan, S.

    2009-01-01

    Process of composting has been developed for recycling of organic fraction of municipal solid waste (MSW). The bioreactor design was modified to reduce the composting process time. The main goal of this investigation was to find the optimal value of time period for composting of MSW in thermophilic bioreactor under aerobic condition. The temperature profiles correlated well with experimental data obtained during the maturation process. During this period biological degraders are introduced in to the reactor to accelerate the composting process. The compost materials were analyzed at various stages and the environmental parameters were considered. The final composting materials contained large organic content with in a short duration of 40 days. The quantity of volume reduction of raw MSW was 78%. The test result shows that the final compost material from the thermophilic reactor provides good humus to build up soil characteristics and some basic plant nutrients

  7. Discrimination of thermophilic and mesophilic proteins

    Directory of Open Access Journals (Sweden)

    Vaisman Iosif I

    2010-05-01

    Full Text Available Abstract Background There is a considerable literature on the source of the thermostability of proteins from thermophilic organisms. Understanding the mechanisms for this thermostability would provide insights into proteins generally and permit the design of synthetic hyperstable biocatalysts. Results We have systematically tested a large number of sequence and structure derived quantities for their ability to discriminate thermostable proteins from their non-thermostable orthologs using sets of mesophile-thermophile ortholog pairs. Most of the quantities tested correspond to properties previously reported to be associated with thermostability. Many of the structure related properties were derived from the Delaunay tessellation of protein structures. Conclusions Carefully selected sequence based indices discriminate better than purely structure based indices. Combined sequence and structure based indices improve performance somewhat further. Based on our analysis, the strongest contributors to thermostability are an increase in ion pairs on the protein surface and a more strongly hydrophobic interior.

  8. Thermophilic xylanases: from bench to bottle.

    Science.gov (United States)

    Basit, Abdul; Liu, Junquan; Rahim, Kashif; Jiang, Wei; Lou, Huiqiang

    2018-01-17

    Lignocellulosic biomass is a valuable raw material. As technology has evolved, industrial interest in new ways to take advantage of this raw material has grown. Biomass is treated with different microbial cells or enzymes under ideal industrial conditions to produce the desired products. Xylanases are the key enzymes that degrade the xylosidic linkages in the xylan backbone of the biomass, and commercial enzymes are categorized into different glycoside hydrolase families. Thermophilic microorganisms are excellent sources of industrially relevant thermostable enzymes that can withstand the harsh conditions of industrial processing. Thermostable xylanases display high-specific activity at elevated temperatures and distinguish themselves in biochemical properties, structures, and modes of action from their mesophilic counterparts. Natural xylanases can be further improved through genetic engineering. Rapid progress with genome editing, writing, and synthetic biological techniques have provided unlimited potential to produce thermophilic xylanases in their natural hosts or cell factories including bacteria, yeasts, and filamentous fungi. This review will discuss the biotechnological potential of xylanases from thermophilic microorganisms and the ways they are being optimized and produced for various industrial applications.

  9. Metabolism of pure sulfate-reducing bacteria in the presence of ferrous ions and environmental chages of the medium; Tetsu ion sonzaika ni okeru junsuina ryusan`en kangenkin no taisha to baichi no kankyo henka

    Energy Technology Data Exchange (ETDEWEB)

    Baba, F.; Suzuki, T. [Ajinomoto Co. Inc., Kawasaki (Japan). Technology and Engineering Lab.; Seo, M. [Hokkaido Univ., Sapporo (Japan). Graduate School of Engineering

    1996-10-15

    In this study, the pure sulfate-reducing bacteria were cultured in the medium with different Fe{sup 2+} concentration; shape and activity of the bacteria, the evolution amount of hydrogen sulfide directly related to the breath of the sulfuric acid and the change of the pH value in the medium were investigated during every time interval; and influence on the metabolism of the sulfate-reducing bacteria with Fe{sup 2+} was examined. As a result, the conclusions were obtained as follows: in the case of a medium with high Fe{sup 2+} concentration containing Fe{sup 2+} of 1.0{times}10{sup -2} molkg{sup -1}, the colloidal substance in which the main composition was considered as Fe(OH)2 were present, and they provided a comfortable place for the bacteria to grow. Correspondingly, in the case of a medium with low Fe{sup 2+} concentration containing Fe{sup 2+} of 3.6{times}10{sup -4} molkg{sup -1}, the colloidal substance was small and the number of bacteria was also few. The four kinds of shape of bacteria coexisted in the medium with increasing the culturing time. The hydrogen sulfide was mainly evolved by the bacteria with the comma like shape. During a period that this comma like bacteria actively moved, the hydrogen sulfide evolution increased. 13 refs., 6 figs., 1 tab.

  10. Metabolism of sulfate-reducing bacteria and corrosion behavior of carbon steel in the continuous culturing medium; Renzoku baiyo baichichu ni okeru ryusan`en kangen no taisha to tansoko no fushoku kyodo

    Energy Technology Data Exchange (ETDEWEB)

    Baba, F.; Suzuki, T. [Ajinomoto Co. Inc., Tokyo (Japan); Seo, M. [Hokkaido University, Sapporo (Japan)

    1997-08-25

    Investigations were made on metabolism of sulfate-reducing bacteria and corrosion behavior of carbon steel in the continuous culturing medium. Sulfate-reducing bacteria were cultured for 50 days by supplying the culturing medium prepared to a prescribed chemical composition (containing Fe {sup 2+} at 0.01 mol/kg) at a rate of 10 cm {sup 3}/h, and drawing them out at the same rate. Test carbon steel pieces were immersed into this culturing medium. As a result, the following matters were clarified: the number of bacteria is maintained at more than 10 {sup 10}/cm{sup 3} after several days since inauguration of the immersion, with the bacteria stably producing H2S and FeS until the culturing is finished; comma-shaped bacteria which move actively and rod-shaped bacteria which do not move very actively exist in the culturing medium; a black film has been produced on surface of the test pieces throughout the culturing period, and satin-like corrosion was found underneath the surface; and weight increase of this film and weight decrease of the lower layer progress as the time lapses (the weight decrease of the lower layer has reached 40 mg/cm{sup 2} in 50 days). 28 refs., 8 figs., 1 tab.

  11. Reverse sample genome probing, a new technique for identification of bacteria in environmental samples by DNA hybridization, and its application to the identification of sulfate-reducing bacteria in oil field samples

    International Nuclear Information System (INIS)

    Voordouw, G.; Voordouw, J.K.; Karkhoff-Schweizer, R.R.; Fedorak, P.M.; Westlake, D.W.S.

    1991-01-01

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

  12. Alcohol dehydrogenases from thermophilic and hyperthermophilic archaea and bacteria.

    Science.gov (United States)

    Radianingtyas, Helia; Wright, Phillip C

    2003-12-01

    Many studies have been undertaken to characterise alcohol dehydrogenases (ADHs) from thermophiles and hyperthermophiles, mainly to better understand their activities and thermostability. To date, there are 20 thermophilic archaeal and 17 thermophilic bacterial strains known to have ADHs or similar enzymes, including the hypothetical proteins. Some of these thermophiles are found to have multiple ADHs, sometimes of different types. A rigid delineation of amino acid sequences amongst currently elucidated thermophilic ADHs and similar proteins is phylogenetically apparent. All are NAD(P)-dependent, with one exception that utilises the cofactor F(420) instead. Within the NAD(P)-dependent group, the thermophilic ADHs are orderly clustered as zinc-dependent ADHs, short-chain ADHs, and iron-containing/activated ADHs. Distance matrix calculations reveal that thermophilic ADHs within one type are homologous, with those derived from a single genus often showing high similarities. Elucidation of the enzyme activity and stability, coupled with structure analysis, provides excellent information to explain the relationship between them, and thermophilic ADHs diversity.

  13. Energy transduction and transport processes in thermophilic bacteria

    NARCIS (Netherlands)

    Konings, W. N.; Tolner, B.; Speelmans, G.; Elferink, M. G. L.; de Wit, J. G.; Driessen, A. J. M.

    1992-01-01

    Bacterial growth at the extremes of temperature has remained a fascinating aspect in the study of membrane function and structure. The stability of the integral membrane proteins of thermophiles make them particularly amenable to study. Respiratory enzymes of thermophiles appear to be functionally

  14. Thermophilic slurry-phase treatment of petroleum hydrocarbon waste sludges

    International Nuclear Information System (INIS)

    Castaldi, F.J.; Bombaugh, K.J.; McFarland, B.

    1995-01-01

    Chemoheterotrophic thermophilic bacteria were used to achieve enhanced hydrocarbon degradation during slurry-phase treatment of oily waste sludges from petroleum refinery operations. Aerobic and anaerobic bacterial cultures were examined under thermophilic conditions to assess the effects of mode of metabolism on the potential for petroleum hydrocarbon degradation. The study determined that both aerobic and anaerobic thermophilic bacteria are capable of growth on petroleum hydrocarbons. Thermophilic methanogenesis is feasible during the degradation of hydrocarbons when a strict anaerobic condition is achieved in a slurry bioreactor. Aerobic thermophilic bacteria achieved the largest apparent reduction in chemical oxygen demand, freon extractable oil, total and volatile solid,s and polycyclic aromatic hydrocarbons (PAHs) when treating oily waste sludges. The observed shift with time in the molecular weight distribution of hydrocarbon material was more pronounced under aerobic metabolic conditions than under strict anaerobic conditions. The changes in the hydrocarbon molecular weight distribution, infrared spectra, and PAH concentrations during slurry-phase treatment indicate that the aerobic thermophilic bioslurry achieved a higher degree of hydrocarbon degradation than the anaerobic thermophilic bioslurry during the same time period

  15. Thermophilic fungi in the new age of fungal taxonomy.

    Science.gov (United States)

    de Oliveira, Tássio Brito; Gomes, Eleni; Rodrigues, Andre

    2015-01-01

    Thermophilic fungi are of wide interest due to their potential to produce heat-tolerant enzymes for biotechnological processes. However, the taxonomy of such organisms remains obscure, especially given new developments in the nomenclature of fungi. Here, we examine the taxonomy of the thermophilic fungi most commonly used in industry in light of the recent taxonomic changes following the adoption of the International Code of Nomenclature for Algae, Fungi and Plants and also based on the movement One Fungus = One Name. Despite the widespread use of these fungi in applied research, several thermotolerant fungi still remain classified as thermophiles. Furthermore, we found that while some thermophilic fungi have had their genomes sequenced, many taxa still do not have barcode sequences of reference strains available in public databases. This lack of basic information is a limiting factor for the species identification of thermophilic fungi and for metagenomic studies in this field. Based on next-generation sequencing, such studies generate large amounts of data, which may reveal new species of thermophilic fungi in different substrates (composting systems, geothermal areas, piles of plant material). As discussed in this study, there are intrinsic problems associated with this method, considering the actual state of the taxonomy of thermophilic fungi. To overcome such difficulties, the taxonomic classification of this group should move towards standardizing the commonly used species names in industry and to assess the possibility of including new systems for describing species based on environmental sequences.

  16. Effect of pH buffering capacity and sources of dietary sulfur on rumen fermentation, sulfide production, methane production, sulfate reducing bacteria, and total Archaea in in vitro rumen cultures.

    Science.gov (United States)

    Wu, Hao; Meng, Qingxiang; Yu, Zhongtang

    2015-06-01

    The effects of three types of dietary sulfur on in vitro fermentation characteristics, sulfide production, methane production, and microbial populations at two different buffer capacities were examined using in vitro rumen cultures. Addition of dry distilled grain with soluble (DDGS) generally decreased total gas production, degradation of dry matter and neutral detergent fiber, and concentration of total volatile fatty acids, while increasing ammonia concentration. High buffering capacity alleviated these adverse effects on fermentation. Increased sulfur content resulted in decreased methane emission, but total Archaea population was not changed significantly. The population of sulfate reducing bacteria was increased in a sulfur type-dependent manner. These results suggest that types of dietary sulfur and buffering capacity can affect rumen fermentation and sulfide production. Diet buffering capacity, and probably alkalinity, may be increased to alleviate some of the adverse effects associated with feeding DDGS at high levels. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Thermophilic archaeal enzymes and applications in biocatalysis.

    Science.gov (United States)

    Littlechild, Jennifer A

    2011-01-01

    Thermophilic enzymes have advantages for their use in commercial applications and particularly for the production of chiral compounds to produce optically pure pharmaceuticals. They can be used as biocatalysts in the application of 'green chemistry'. The thermophilic archaea contain enzymes that have already been used in commercial applications such as the L-aminoacylase from Thermococcus litoralis for the resolution of amino acids and amino acid analogues. This enzyme differs from bacterial L-aminoacylases and has similarities to carboxypeptidases from other archaeal species. An amidase/γ-lactamase from Sulfolobus solfataricus has been used for the production of optically pure γ-lactam, the building block for antiviral carbocyclic nucleotides. This enzyme has similarities to the bacterial signature amidase family. An alcohol dehydrogenase from Aeropyrum pernix has been used for the production of optically pure alcohols and is related to the zinc-containing eukaryotic alcohol dehydrogenases. A transaminase and a dehalogenase from Sulfolobus species have also been studied. The archaeal transaminase is found in a pathway for serine synthesis which is found only in eukaryotes and not in bacteria. It can be used for the asymmetric synthesis of homochiral amines of high enantioselective purity. The L-2-haloacid dehalogenase has applications both in biocatalysis and in bioremediation. All of these enzymes have increased thermostability over their mesophilic counterparts.

  18. Cellulolytic properties of an extremely thermophilic anaerobe

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, J A; Morgan, H W; Daniel, R M [Waikato Univ., Hamilton (New Zealand). Microbial Biochemistry and Biotechnology Unit

    1990-09-01

    An extremely thermophilic anaerobe was isolated from a New Zealand hot spring by incubating bacterial mat strands in a medium containing xylan. The Gramreaction-negative organism that was subsequently purified had a temperature optimum of 70deg C and a pH optimum of 7.0. The isolate, designated strain H173, grew on a restricted range of carbon sources. In batch culture H173 could degrade Avicel completely when supplied at 5 or 10 g l{sup -1}. There was an initial growth phase, during which a cellulase complex was produced and carbohydrates fermented to form acetic and lactic acids, followed by a phase where cells were not metabolising but the cellulase complex actively converted cellulose to glucose. When co-cultered with strain Rt8.B1, an ethanologenic extreme thermophile, glucose was fermented to ethanol and acetate, and no reducing sugars accumulated in the medium. In pH controlled batch culture H173 produced an increased amount of lactate and acetate but there was again a phase when reducing sugars accumulated in the medium, and these were converted to ethanol by co-culture with Rt8.B1. (orig.).

  19. Comparison of the thermostability of cellulases from various thermophilic fungi

    Energy Technology Data Exchange (ETDEWEB)

    Wojtczak, G; Breuil, C; Yamada, J; Saddler, J N

    1987-10-01

    The cellulase activities of six thermophilic fungi were compared. Although the thermophilic fungi grew at relatively high temperatures (> 45/sup 0/C) the optimum temperatures for assaying the various cellulase activities were only slightly higher than the optimum temperatures for the mesophilic fungi, Trichoderma harzianum. Over prolonged incubation (> 24 h) the thermophilic strains demonstrated a higher hydrolytic potential as a result of the greater thermostability of the cellulase components. Although the extracellular cellulase activities had similar pH and temperature optima, in some cases the thermostability of the extracellular components were considerably lower.

  20. DNA fingerprinting of spore-forming bacterial isolates, using Bacillus ...

    African Journals Online (AJOL)

    User

    Full Length Research Paper ... resulted in a search for better techniques for classifying ... only a few laboratories worldwide are able to perform a ... MATERIALS AND METHODS. Bacterial ... s with distilled water and blotted dry with tissue paper (Kimberly- ... A test on the quality and quantity of DNA extracted was conducted.

  1. Determination of the Persistence of Non-Spore-Forming ...

    Science.gov (United States)

    Report This report presents the results of an investigation to evaluate the persistence (or natural attenuation) of Yersinia pestis (Y. pestis), Francisella tularensis (F. tularensis), and Burkholderia mallei (B. mallei) on glass and soil under multiple environmental conditions and time points.

  2. LEVELS AND TYPES OF AEROBIC SPORE FORMING BACTERIA ...

    African Journals Online (AJOL)

    The four companies whose packaged product were studied had an average plate total spore counts as follows: Company A=6.2x 103; Company B= 3.1x 104; Company C= 6.0x 104 and Company D= 3.1x102 colony forming units per gram, respectively. Identification tests showed that among the aerobic spore formers were ...

  3. Radiosensitivity of bacteriophages of aerobic spore-forming microorganisms

    International Nuclear Information System (INIS)

    Polkhovskij, V.A.

    1978-01-01

    Under conditions of direct radiation effect on seven original phages of aerobic sporeforming bacteria and four standard phages of E. coli it has been established, that all of them had different sensitivity to gamma radiation and were divided into four groups. The phages of E. coli of T series and in particular the T2 phage turned out the most sensitive. The phages of aerobic sporeforming bacilli were more resistant to gamma radiation effect, which is connected, apparently, with a lower DNA content in phages of Bacillus in comparison with the T phages

  4. Mosquitocidal toxins of spore forming bacteria: recent advancement ...

    African Journals Online (AJOL)

    Mosquito borne diseases form a major component of vector borne diseases from all over the world. Several control strategies have been adopted to control diseases transmitted by mosquitoes. The discovery of highly potential bacteriocides like Bacillus sphaericus (Bs) and Bacillus thuringiensis subsp. israelensis (Bti) have ...

  5. Xylanase, CM-cellulase and avicelase production by the thermophilic fungus Sporotrichum thermophile

    Energy Technology Data Exchange (ETDEWEB)

    Margaritis, A; Merchant, R; Yaguchi, M

    1983-01-01

    When wheat straw was used as C source, S. thermophile produced large amounts of xylanase extracellularly in addition to CM-cellulase and Avicelase. These enzymes were isolated by alcohol precipitation, desalting, and column chromatography. The molecular weights were estimated to be 25,0065,000 and 84,000 for xylanase, CM-cellulase, and Avicelase, respectively. Serine and threonine were the most abundant amino acids and these enzymes are very acidic proteins.

  6. Myceliophthora thermophila syn. Sporotrichum thermophile: a thermophilic mould of biotechnological potential.

    Science.gov (United States)

    Singh, Bijender

    2016-01-01

    Myceliophthora thermophila syn. Sporotrichum thermophile is a ubiquitous thermophilic mould with a strong ability to degrade organic matter during optimal growth at 45 °C. Both genome analysis and experimental data have suggested that the mould is capable of hydrolyzing all major polysaccharides found in biomass. The mould is able to secrete a large number of hydrolytic enzymes (cellulases, laccases, xylanases, pectinases, lipases, phytases and some other miscellaneous enzymes) employed in various biotechnological applications. Characterization of the biomass-hydrolyzing activity of wild and recombinant enzymes suggests that this mould is highly efficient in biomass decomposition at both moderate and high temperatures. The native enzymes produced by the mould are more efficient in activity than their mesophilic counterparts beside their low enzyme titers. The mould is able to synthesize various biomolecules, which are used in multifarious applications. Genome sequence data of M. thermophila also supported the physiological data. This review describes the biotechnological potential of thermophilic mould, M. thermophila supported by genomic and experimental evidences.

  7. Diversity of thermophilic archaeal isolates from hot springs in Japan

    Science.gov (United States)

    Itoh, Takashi; Yoshikawa, Naoto; Takashina, Tomonori

    2005-09-01

    In the light of the significance of extremophiles as model organisms to access possible extraterrestiral life, we provide a short review of the systematics of thermophilic Archaea, and introduce our exploratory research of novel thermophilic Archaea from hot springs in Japan. Up to date, we have isolated 162 strains of the thermophilic Archaea from hot springs in Japan by the enrichment method or the most probable number/PCR method, and the 16S rRNA gene sequences were determined to reveal their phylogenetic diversity. The sequence comparison illustrated that the isolates belonged to the orders Sulfolobales (117 isolates) , Thermoproteales (29 isolates), Desulfurococcales (8 isolates) and Thermoplasmatales (8 isolates), and there were six separate lineages representing new genera, and at least seven new species as predicted by the phylogenetic distance to known species. The collection of isolates not only included novel taxa but would give some implication for a necessity to reevaluate the current taxonomy of the thermophilic Archaea.

  8. Cellulolytic potential of thermophilic species from four fungal orders

    DEFF Research Database (Denmark)

    Busk, Peter Kamp; Lange, Lene

    2013-01-01

    and in characterization of their industrially useful enzymes. In the present study we investigated the cellulolytic potential of 16 thermophilic fungi from the three ascomycete orders Sordariales, Eurotiales and Onygenales and from the zygomycete order Mucorales thus covering all fungal orders that include thermophiles....... Thermophilic fungi are the only described eukaryotes that can grow at temperatures above 45 ºC. All 16 fungi were able to grow on crystalline cellulose but their secreted enzymes showed widely different cellulolytic activities, pH optima and thermostabilities. Interestingly, in contrast to previous reports, we......Elucidation of fungal biomass degradation is important for understanding the turnover of biological materials in nature and has important implications for industrial biomass conversion. In recent years there has been an increasing interest in elucidating the biological role of thermophilic fungi...

  9. The effects of micro-aeration on the phylogenetic diversity of microorganisms in a thermophilic anaerobic municipal solid-waste digester.

    Science.gov (United States)

    Tang, Yueqin; Shigematsu, Toru; Ikbal; Morimura, Shigeru; Kida, Kenji

    2004-05-01

    We demonstrated previously that micro-aeration allows construction of an effective thermophilic methane-fermentation system for treatment of municipal solid waste (MSW) without production of H(2)S. In the present study, we compared the microbial communities in a thermophilic MSW digester without aeration and with micro-aeration by fluorescence in situ hybridization (FISH), denaturing gradient gel electrophoresis (DGGE), phylogenetic analysis of libraries of 16S rRNA gene clones and quantitative real-time PCR. Moreover, we studied the activity of sulfate-reducing bacteria (SRB) by analysis of the transcription of the gene for dissimilatory sulfite reductase (dsr). Experiments using FISH revealed that microorganisms belonging to the domain Bacteria dominated in the digester both without aeration and with micro-aeration. Phylogenetic analysis based on 16S rRNA gene and analysis of bacteria by DGGE did not reveal any obvious difference within the microbial communities under the two aeration conditions, and bacteria affiliated with the phylum Firmicutes were dominant. In Archaea, the population of Methanosarcina decreased while the population of Methanoculleus increased as a result of micro-aerations as revealed by the analysis of 16S rRNA gene clones and quantitative real-time PCR. Reverse transcription and PCR (RT-PCR) demonstrated the transcription of dsrA not only in the absence of aeration but also in the presence of micro-aeration, even under conditions where no H(2)S was detected in the biogas. In conclusion, micro-aeration has no obvious effects on the phylogenetic diversity of microorganisms. Furthermore, the activity of SRBs in the digester was not repressed even though the concentration of H(2)S in the biogas was very low under the micro-aeration conditions.

  10. (Hyper)thermophilic enzymes: production and purification.

    Science.gov (United States)

    Falcicchio, Pierpaolo; Levisson, Mark; Kengen, Servé W M; Koutsopoulos, Sotirios

    2014-01-01

    The discovery of thermophilic and hyperthermophilic microorganisms, thriving at environmental temperatures near or above 100 °C, has revolutionized our ideas about the upper temperature limit at which life can exist. The characterization of (hyper)thermostable proteins has broadened our understanding and presented new opportunities for solving one of the most challenging problems in biophysics: how is structural stability and biological function maintained at high temperatures where "normal" proteins undergo dramatic structural changes? In our laboratory we have purified and studied many thermostable and hyperthermostable proteins in an attempt to determine the molecular basis of heat stability. Here, we present methods to express such proteins and enzymes in E. coli and provide a general protocol for overproduction and purification. The ability to produce enzymes that retain their stability and activity at elevated temperatures creates exciting opportunities for a wide range of biocatalytic applications.

  11. The cellulase activity of an extreme thermophile

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, J A [Meat Industry Research Inst. of New Zealand, Hamilton (New Zealand); Morgan, H W; Daniel, R M [Waikato Univ., Hamilton (New Zealand). Microbial Biochemistry and Biotechnology Unit

    1991-05-01

    The carboxymethylcellulase activity concentrated from the extremely thermophilic anaerobe H173 was found to have a pH optimum of 6.5-7.0. The enzyme activity was stabilised by the addition of dithiothreitol and CaCl{sub 2}.2H{sub 2}O and was very stable at 80deg C, retaining 77% of the inital activity after 120 min incubation. At 90deg C however, 50% activity remained after 9 min and after 120 min only 3% of the initial activity remained. With the enzyme dissolved in buffer, glucose and cellobiose were formed from the hydrolysis of Avicel. In culture medium the Avicel-solubilising activity was insensitive to the presence of up to 50 mM glucose and showed linear glucose accumulation over a period of days at 70deg C. HPLC analysis established that glucose was the major end-product of hydrolysis in the culture broths. (orig.).

  12. Mesophilic and thermophilic anaerobic digestion of sulphate-containing wastewaters.

    Science.gov (United States)

    Colleran, E; Pender, S

    2002-01-01

    The effect of sulphate at an influent chemical oxygen demand (COD):sulphate ratio of 4 on the operational performance of anaerobic hybrid reactors treating molasses wastewater was investigated under mesophilic and thermophilic conditions in a long-term laboratory-scale study over a 1,081 day period. The presence of sulphate reduced the COD removal efficiency under both mesophilic and thermophilic conditions. At 55 degrees C, effluent acetate levels were consistently greater than 4000 mg l(-1) indicating that thermophilic acetate-utilising methane-producing bacteria (MPB) or sulphate-reducing bacteria (SRB) had not developed in the reactor under the conditions applied. At 37 degrees C, acetate was exclusively utilised by acetoclastic methanogens, whereas H2-utilising SRB predominated over H2-utilising MPB in the competition for hydrogen. By contrast, hydrogenotrophic MPB were shown to outcompete H2-utilising SRB during long-term thermophilic operation. 16SrDNA analysis of the seed sludge and reactor biomass on conclusion of the 37 degrees C and 55 degrees C trials illustrated that the dominant methanogen present on conclusion of the thermophilic trial in the absence of influent sulphate was related to Methanocorpusculum parvuum, and was capable of growth on both acetate and hydrogen. By contrast, an organism closely related to Methanobacterium thermoautotrophicum was the dominant methanogen present in the sulphate-fed reactor on completion of the thermophilic trial.

  13. Thermosyntropha lipolytica gen. nov., sp. nov., a lipolytic, anaerobic, alkalitolerant, thermophilic bacterium utilizing short- and long-chain fatty acids in syntrophic coculture with a methanogenic archaeum.

    Science.gov (United States)

    Svetlitshnyi, V; Rainey, F; Wiegel, J

    1996-10-01

    Three strains of an anaerobic thermophilic organoheterotrophic lipolytic alkalitolerant bacterium, Thermosyntropha lipolytica gen. nov., sp. nov. (type strain JW/VS-265T; DSM 11003), were isolated from alkaline hot springs of Lake Bogoria (Kenya). The cells were nonmotile, non-spore forming, straight or slightly curved rods. At 60 degrees C the pH range for growth determined at 25 degrees C [pH25 degrees C] was 7.15 to 9.5, with an optimum between 8.1 and 8.9 (pH60 degrees C of 7.6 and 8.1). At a pH25 degrees C of 8.5 the temperature range for growth was from 52 to 70 degrees C, with an optimum between 60 and 66 degrees C. The shortest doubling time was around 1 h. In pure culture the bacterium grew in a mineral base medium supplemented with yeast extract, tryptone, Casamino Acids, betaine, and crotonate as carbon sources, producing acetate as a major product and constitutively a lipase. During growth in the presence of olive oil, free long-chain fatty acids were accumulated in the medium but the pure culture could not utilize olive oil, triacylglycerols, short- and long-chain fatty acids, and glycerol for growth. In syntrophic coculture (Methanobacterium strain JW/VS-M29) the lipolytic bacteria grew on triacylglycerols and linear saturated and unsaturated fatty acids with 4 to 18 carbon atoms, but glycerol was not utilized. Fatty acids with even numbers of carbon atoms were degraded to acetate and methane, while from odd-numbered fatty acids 1 mol of propionate per mol of fatty acid was additionally formed. 16S rDNA sequence analysis identified Syntrophospora and Syntrophomonas spp. as closest phylogenetic neighbors.

  14. Sulfate-reducing bacteria in anaerobic bioreactors

    NARCIS (Netherlands)

    Oude Elferink, S.J.W.H.

    1998-01-01

    The treatment of industrial wastewaters containing high amounts of easily degradable organic compounds in anaerobic bioreactors is a well-established process. Similarly, wastewaters which in addition to organic compounds also contain sulfate can be treated in this way. For a long time, the

  15. Optimizing substrate for sulfate-reducing bacteria

    International Nuclear Information System (INIS)

    Chang, L.K.; Updegraff, D.M.; Wildeman, T.R.

    1991-01-01

    Microbial sulfate reduction followed by sulfide precipitation effectively removes heavy metals from wastewaters. The substrate in the anaerobic zone in a constructed wetland can be designed to emphasize this removal process. This group of bacteria requires CH 2 O, P, N, and SO 4 =, reducing conditions, and pH range of 5-9 (pH=7 is optimum). The objective of this study was to find an inexpensive source of nutrients that would give the best initial production of sulfide and make a good wetland substrate. All tested materials contain sufficient P and N; mine drainage provides sulfate. Thus, tests focused on finding organic material that provides the proper nutrients and does not cause the culture to fall below pH of 5. Among chemical nutrients, sodium lactate combined with (NH 4 ) 2 HPO 4 were the only compounds that produced sulfide after 11 days. Among complex nutrients, only cow manure produced sulfide after 26 days. Among complex carbohydrates, cracked corn and raw rice produced sulfide after 10 days. Most substrates failed to produce sulfide because anaerobic fermentation reduced the pH below 5. Presently, cracked corn is the best candidate for a substrate. Five grams of cow manure produced 0.14 millimole of sulfide whereas 0.1 g of cracked corn produced 0.22 millimole

  16. Corrosion behavior of carbon steel exposed for long time to an inoculation medium of sulfate-reducing bacteria; Ryusan`en kangenkin ga seisokusuru baichi ni chokikan shinshinshita tansoko no fushoku kyodo

    Energy Technology Data Exchange (ETDEWEB)

    Baba, F.; Suzuki, T. [Ajinomoto Co. Inc., Kawasaki (Japan). Technology and Engineering Lab.; Seo, M. [Hokkaido Univ., Sapporo (Japan). Graduate School of Engineering

    1996-10-15

    In this paper, carbon steel was exposed more than six weeks to an inoculation medium of the sulfate-reducing bacteria in which the Fe{sup 2+} concentration was adjusted to a fixed value, the corrosion behavior of carbon steel was investigated by measuring the weight change and surface analysis using EPMA. As a result, the conclusions were obtained as follows: in the case of the medium with high Fe{sup 2+} concentration, the corrosion rate reached a maximum. In this case, the corrosion rate was suppressed to be low during the exposure for up to three weeks, and was increased above four weeks. The corrosion rate became 0.06 mm year{sup -1} by extrapolating the weight loss during the exposure up to six weeks. This value was higher than the average corrosion rate of carbon steel in a neutral solution with deaeration. It was shown from the analysis results using the EPMA that the FeS scale area covered on the surface of carbon steel would act as a cathode, and the other area would act as an anode. The formation of a scale effectively acting as a cathode depended on the exposure time and the formation of FeS in the medium. 15 refs., 10 figs., 1 tab.

  17. Characterization of 16S rRNA genes from oil field microbial communities indicates the presence of a variety of sulfate-reducing, fermentative, and sulfide-oxidizing bacteria.

    Science.gov (United States)

    Voordouw, G; Armstrong, S M; Reimer, M F; Fouts, B; Telang, A J; Shen, Y; Gevertz, D

    1996-05-01

    Oil field bacteria were characterized by cloning and sequencing of PCR-amplified 16S rRNA genes. A variety of gram-negative, sulfate-reducing bacteria was detected (16 members of the family Desulfovibrionaceae and 8 members of the family Desulfobacteriaceae). In contrast, a much more limited number of anaerobic, fermentative, or acetogenic bacteria was found (one Clostridium sp., one Eubacterium sp., and one Synergistes sp.). Potential sulfide oxidizers and/or microaerophiles (Thiomicrospira, Arcobacter, Campylobacter, and Oceanospirillum spp.) were also detected. The first two were prominently amplified from uncultured production water DNA and represented 28 and 47% of all clones, respectively. Growth on media containing sulfide as the electron donor and nitrate as the electron acceptor and designed for the isolation of Thiomicrospira spp. gave only significant enrichment of the Campylobacter sp., which was shown to be present in different western Canadian oil fields. This newly discovered sulfide oxidizer may provide a vital link in the oil field sulfur cycle by reoxidizing sulfide formed by microbial sulfate or sulfur reduction.

  18. Conductive iron oxides accelerate thermophilic methanogenesis from acetate and propionate.

    Science.gov (United States)

    Yamada, Chihaya; Kato, Souichiro; Ueno, Yoshiyuki; Ishii, Masaharu; Igarashi, Yasuo

    2015-06-01

    Anaerobic digester is one of the attractive technologies for treatment of organic wastes and wastewater, while continuous development and improvements on their stable operation with efficient organic removal are required. Particles of conductive iron oxides (e.g., magnetite) are known to facilitate microbial interspecies electron transfer (termed as electric syntrophy). Electric syntrophy has been reported to enhance methanogenic degradation of organic acids by mesophilic communities in soil and anaerobic digester. Here we investigated the effects of supplementation of conductive iron oxides (magnetite) on thermophilic methanogenic microbial communities derived from a thermophilic anaerobic digester. Supplementation of magnetite accelerated methanogenesis from acetate and propionate under thermophilic conditions, while supplementation of ferrihydrite also accelerated methanogenesis from propionate. Microbial community analysis revealed that supplementation of magnetite drastically changed bacterial populations in the methanogenic acetate-degrading cultures, in which Tepidoanaerobacter sp. and Coprothermobacter sp. dominated. These results suggest that supplementation of magnetite induce electric syntrophy between organic acid-oxidizing bacteria and methanogenic archaea and accelerate methanogenesis even under thermophilic conditions. Findings from this study would provide a possibility for the achievement of stably operating thermophilic anaerobic digestion systems with high efficiency for removal of organics and generation of CH4. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  19. Thermophilic subseafloor microorganisms from the 1996 North Gorda Ridge eruption

    Science.gov (United States)

    Summit, Melanie; Baross, John A.

    1998-12-01

    High-temperature microbes were present in two hydrothermal event plumes (EP96A and B) resulting from the February-March 1996 eruptions along the North Gorda Ridge. Anaerobic thermophiles were cultured from 17 of 22 plume samples at levels exceeding 200 organisms per liter; no thermophiles were cultured from any of 12 samples of background seawater. As these microorganisms grow at temperatures of 50-90°C, they could not have grown in the event plume and instead most probably derived from a subseafloor environment tapped by the event plume source fluids. Event plumes are thought to derive from a pre-existing subseafloor fluid reservoir, which implies that these thermophiles are members of a native subseafloor community that was present before the eruptive event. Thermophiles also were cultured from continuous chronic-style hydrothermal plumes in April 1996; these plumes may have formed from cooling lava piles. To better understand the nutritional, chemical, and physical constraints of pre-eruptive crustal environments, seven coccoidal isolates from the two event plumes were partially characterized. Results from nutritional and phylogenetic studies indicate that these thermophiles are heterotrophic archaea that represent new species, and probably a new genus, within the Thermococcales.

  20. Glycoside hydrolase activities of thermophilic bacterial consortia adapted to switchgrass.

    Science.gov (United States)

    Gladden, John M; Allgaier, Martin; Miller, Christopher S; Hazen, Terry C; VanderGheynst, Jean S; Hugenholtz, Philip; Simmons, Blake A; Singer, Steven W

    2011-08-15

    Industrial-scale biofuel production requires robust enzymatic cocktails to produce fermentable sugars from lignocellulosic biomass. Thermophilic bacterial consortia are a potential source of cellulases and hemicellulases adapted to harsher reaction conditions than commercial fungal enzymes. Compost-derived microbial consortia were adapted to switchgrass at 60°C to develop thermophilic biomass-degrading consortia for detailed studies. Microbial community analysis using small-subunit rRNA gene amplicon pyrosequencing and short-read metagenomic sequencing demonstrated that thermophilic adaptation to switchgrass resulted in low-diversity bacterial consortia with a high abundance of bacteria related to thermophilic paenibacilli, Rhodothermus marinus, and Thermus thermophilus. At lower abundance, thermophilic Chloroflexi and an uncultivated lineage of the Gemmatimonadetes phylum were observed. Supernatants isolated from these consortia had high levels of xylanase and endoglucanase activities. Compared to commercial enzyme preparations, the endoglucanase enzymes had a higher thermotolerance and were more stable in the presence of 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]), an ionic liquid used for biomass pretreatment. The supernatants were used to saccharify [C2mim][OAc]-pretreated switchgrass at elevated temperatures (up to 80°C), demonstrating that these consortia are an excellent source of enzymes for the development of enzymatic cocktails tailored to more extreme reaction conditions.

  1. Thermophilic growth and enzymatic thermostability are polyphyletic traits within Chaetomiaceae.

    Science.gov (United States)

    van den Brink, Joost; Facun, Kryss; de Vries, Michel; Stielow, J Benjamin

    2015-12-01

    Thermophilic fungi have the potential to produce industrial-relevant thermostable enzymes, in particular for the degradation of plant biomass. Sordariales is one of the few fungal orders containing several thermophilic taxa, of which many have been associated with the production of thermostable enzymes. The evolutionary affiliation of Sordariales fungi, especially between thermophiles and non-thermophilic relatives, is however poorly understood. Phylogenetic analysis within the current study was based on sequence data, derived from a traditional Sanger and highly multiplexed targeted next generation sequencing approach of 45 isolates. The inferred phylogeny and detailed growth analysis rendered the trait 'thermophily' as polyphyletic within Chaetomiaceae (Sordariales, Sordariomycetes), and characteristic to: Myceliophthora spp., Thielavia terrestris, Chaetomium thermophilum, and Mycothermus thermophilus. Compared to mesophiles, the isolates within thermophilic taxa produced enzyme mixtures with the highest thermostability of known cellulase activities. Temperature profiles of the enzyme activities correlated strongly with the optimal growth temperatures of the isolates but not with their phylogenetic relationships. This strong correlation between growth and enzyme characteristics indicated that detailed analysis of growth does give predictive information on enzyme physiology. The variation in growth and enzyme characteristics reveals these fungi as an excellent platform to better understand fungal thermophily and enzyme thermostability. Copyright © 2015 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  2. Ecology and biotechnological potential of the thermophilic fermentative Coprothermobacter spp.

    Science.gov (United States)

    Gagliano, M C; Braguglia, C M; Petruccioli, M; Rossetti, S

    2015-05-01

    Thermophilic bacteria have been isolated from several terrestrial, marine and industrial environments. Anaerobic digesters treating organic wastes are often an important source of these microorganisms, which catalyze a wide array of metabolic processes. Moreover, organic wastes are primarily composed of proteins, whose degradation is often incomplete. Coprothermobacter spp. are proteolytic anaerobic thermophilic microbes identified in several studies focused on the analysis of the microbial community structure in anaerobic thermophilic reactors. They are currently classified in the phylum Firmicutes; nevertheless, several authors showed that the Coprothermobacter group is most closely related to the phyla Dictyoglomi and Thermotoga. Since only a few proteolytic anaerobic thermophiles have been characterized so far, this microorganism has attracted the attention of researchers for its potential applications with high-temperature environments. In addition to proteolysis, Coprothermobacter spp. showed several metabolic abilities and may have a biotechnological application either as source of thermostable enzymes or as inoculum in anaerobic processes. Moreover, they can improve protein degradation by establishing a syntrophy with hydrogenotrophic archaea. To gain a better understanding of the phylogenesis, metabolic capabilities and adaptations of these microorganisms, it is of importance to better define the role in thermophilic environments and to disclose properties not yet investigated. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Protease Production by Different Thermophilic Fungi

    Science.gov (United States)

    Macchione, Mariana M.; Merheb, Carolina W.; Gomes, Eleni; da Silva, Roberto

    A comparative study was carried out to evaluate protease production in solid-state fermentation (SSF) and submerged fermentation (SmF) by nine different thermophilic fungi — Thermoascus aurantiacus Miehe, Thermomyces lanuginosus, T. lanuginosus TO.03, Aspergillus flavus 1.2, Aspergillus sp. 13.33, Aspergillus sp. 13.34, Aspergillus sp. 13.35, Rhizomucor pusillus 13.36 and Rhizomucor sp. 13.37 — using substrates containing proteins to induce enzyme secretion. Soybean extract (soybean milk), soybean flour, milk powder, rice, and wheat bran were tested. The most satisfactory results were obtained when using wheat bran in SSF. The fungi that stood out in SSF were T. lanuginosus, T. lanuginosus TO.03, Aspergillus sp. 13.34, Aspergillus sp. 13.35, and Rhizomucor sp. 13.37, and those in SmF were T. aurantiacus, T. lanuginosus TO.03, and 13.37. In both fermentation systems, A. flavus 1.2 and R. pusillus 13.36 presented the lowest levels of proteolytic activity.

  4. Exogenous cellulases of thermophilic micromycetes. Pt. 1. Selection of producers

    Energy Technology Data Exchange (ETDEWEB)

    Kvesitadze, G; Kvachadze, L; Aleksidze, T; Chartishvili, D K

    1986-01-01

    More than 600 micromycetes - representatives of different genera have been investigated for their ability to produce exogenous cellulases. Most of the investigated cultures were found to produce these enzymes, 24 cultures being thermophilic, and 18 thermotolerant. Cellulase or its derivatives proved to be the most favourable carbon source for cellulase secretion. None of the thermophilic cultures studied manifested the ability of exogenous exoglucanase biosynthesis. Using UV-rays as mutagen, a mutant strain A. terreus T-49 has been obtained being characterized by an increased endo-glucanase and cellobiase activity, as compared to the initial strains. The cellulase preparations of thermophilic micromycetes contain one cellulasic component: endo-glucanase, or two: endo-glucanase and cellobiase.

  5. Contribution to the study of the role of sulfate-reducing bacteria in bio-corrosion phenomenon; Contribution a l'etude du role des bacteries sulfato-reductrices dans les phenomenes de biocorrosion

    Energy Technology Data Exchange (ETDEWEB)

    Chatelus, C

    1987-11-15

    By their metabolic activities of hydrogen consumption and of sulfides production, the sulfate-reducing bacteria are the main bacteria responsible of the metallic corrosion phenomena in the absence of oxygen. A physiological and enzymatic study of some Desulfovibrio has contributed to the understanding of the role of these bacteria in the anaerobic bio-corrosion phenomena. Desulfovibrio (D.) vulgaris in organic medium, after having oxidized the lactate, consumes the hydrogen formed by the electrochemical reaction of iron dissolution. The Desulfovibrio can be responsible either of a corrosion by a direct contact with the metal in using the H{sub 2} layer formed at its surface, (bacteria are then adsorbed at the surface because of an iron sulfide crystalline lattice), or of a distant corrosion in consuming the dissolved or gaseous hydrogen. As their hydrogenases can be stable in time independently of the cellular structure (D. vulparis) and active at high temperatures (to 70 C - 75 C) (D. baculatus), these bacteria can act in conditions incompatible with the viability of cells but compatible with the enzymatic expression. A study in terms of temperature has shown that inside the mesophilic group of the Desulfovibrio, the behaviour towards this parameter is specific to each bacteria, that accounts for the permanent presence of the representatives of this population in sites where the temperature variations are important. A change of some degrees Celsius can induce modifications in the yields of bacteria growth and by a consequence in variations in the corrosion intensity. Moreover, sulfate D. multispirans can reduce with specific velocities of different growth, the nitrate, the nitrite and the fumarate. Some sulfato-reducing could then adapt themselves to the variations of concentrations in electron acceptors and metabolize the oxidized substances used as biocides too. The choice of an electron acceptor rather than another do not depend uniquely of the specificity of

  6. Contribution to the study of the role of sulfate-reducing bacteria in bio-corrosion phenomenon; Contribution a l'etude du role des bacteries sulfato-reductrices dans les phenomenes de biocorrosion

    Energy Technology Data Exchange (ETDEWEB)

    Chatelus, C

    1987-11-15

    By their metabolic activities of hydrogen consumption and of sulfides production, the sulfate-reducing bacteria are the main bacteria responsible of the metallic corrosion phenomena in the absence of oxygen. A physiological and enzymatic study of some Desulfovibrio has contributed to the understanding of the role of these bacteria in the anaerobic bio-corrosion phenomena. Desulfovibrio (D.) vulgaris in organic medium, after having oxidized the lactate, consumes the hydrogen formed by the electrochemical reaction of iron dissolution. The Desulfovibrio can be responsible either of a corrosion by a direct contact with the metal in using the H{sub 2} layer formed at its surface, (bacteria are then adsorbed at the surface because of an iron sulfide crystalline lattice), or of a distant corrosion in consuming the dissolved or gaseous hydrogen. As their hydrogenases can be stable in time independently of the cellular structure (D. vulparis) and active at high temperatures (to 70 C - 75 C) (D. baculatus), these bacteria can act in conditions incompatible with the viability of cells but compatible with the enzymatic expression. A study in terms of temperature has shown that inside the mesophilic group of the Desulfovibrio, the behaviour towards this parameter is specific to each bacteria, that accounts for the permanent presence of the representatives of this population in sites where the temperature variations are important. A change of some degrees Celsius can induce modifications in the yields of bacteria growth and by a consequence in variations in the corrosion intensity. Moreover, sulfate D. multispirans can reduce with specific velocities of different growth, the nitrate, the nitrite and the fumarate. Some sulfato-reducing could then adapt themselves to the variations of concentrations in electron acceptors and metabolize the oxidized substances used as biocides too. The choice of an electron acceptor rather than another do not depend uniquely of the specificity of

  7. An efficient Azorean thermophilic consortium for lignocellulosic biomass degradation

    OpenAIRE

    Martins, Rita; Teixeira, Mário; Toubarro, Duarte; Simões, Nelson; Domingues, Lucília; Teixeira, J. A.

    2015-01-01

    [Excerpt] Lignocellulosic plant biomass is being envisioned by biorefinery industry as an alternative to current petroleum platform because of the large scale availability, low cost and environmentally benign production. The industrial bioprocessing designed to transform lignocellulosic biomass into biofuels are harsh and the enzymatic reactions may be severely compromised reducing the production of fermentable sugars from lignocellulosic biomass. Thermophilic bacteria consortium are a potent...

  8. Design of A solar Thermophilic Anaerobic Reactor for Small Farms

    NARCIS (Netherlands)

    Mashad, El H.; Loon, van W.K.P.; Zeeman, G.; Bot, G.P.A.; Lettinga, G.

    2004-01-01

    A 10 m(3) completely stirred tank reactor has been designed for anaerobic treatment of liquid cow manure under thermophilic conditions (50degreesC), using a solar heating system mounted on the reactor roof. Simulation models for two systems have been developed. The first system consists of loose

  9. Isolation of soil thermophilic strains of actinomycetes for the ...

    African Journals Online (AJOL)

    use

    2011-12-05

    Dec 5, 2011 ... to high fructose (Pandey et al., 2000; Asgher et al., 2007). *Corresponding ... can be increased by pH, temperature or substrates. ... The following media were used for isolating thermophilic strains of ... To observe the effect of different culture conditions on α-amylase .... Influence of pH on the inactivation of.

  10. Force-dependent melting of supercoiled DNA at thermophilic temperatures.

    Science.gov (United States)

    Galburt, E A; Tomko, E J; Stump, W T; Ruiz Manzano, A

    2014-01-01

    Local DNA opening plays an important role in DNA metabolism as the double-helix must be melted before the information contained within may be accessed. Cells finely tune the torsional state of their genomes to strike a balance between stability and accessibility. For example, while mesophilic life forms maintain negatively superhelical genomes, thermophilic life forms use unique mechanisms to maintain relaxed or even positively supercoiled genomes. Here, we use a single-molecule magnetic tweezers approach to quantify the force-dependent equilibrium between DNA melting and supercoiling at high temperatures populated by Thermophiles. We show that negatively supercoiled DNA denatures at 0.5 pN lower tension at thermophilic vs. mesophilic temperatures. This work demonstrates the ability to monitor DNA supercoiling at high temperature and opens the possibility to perform magnetic tweezers assays on thermophilic systems. The data allow for an estimation of the relative energies of base-pairing and DNA bending as a function of temperature and support speculation as to different general mechanisms of DNA opening in different environments. Lastly, our results imply that average in vivo DNA tensions range between 0.3 and 1.1 pN. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Hydrogenomics of the extremely thermophilic bacterium Caldicellulosiruptor saccharolyticus

    NARCIS (Netherlands)

    Werken, van de H.J.G.; Verhaart, M.R.A.; Vanfossen, A.L.; Willquist, K.; Lewis, D.L.; Nichols, J.D.; Goorissen, H.P.; Mongodin, E.F.; Nelson, K.E.; Niel, van E.W.J.; Stams, A.J.M.; Ward, D.E.; Vos, de W.M.; Oost, van der J.; Kelly, R.M.; Kengen, S.W.M.

    2008-01-01

    Caldicellulosiruptor saccharolyticus is an extremely thermophilic, gram-positive anaerobe which ferments cellulose-, hemicellulose- and pectin-containing biomass to acetate, CO(2), and hydrogen. Its broad substrate range, high hydrogen-producing capacity, and ability to coutilize glucose and xylose

  12. Production of α-amylase from some thermophilic Aspergillus species ...

    African Journals Online (AJOL)

    In this study, thermostable amylase activities of some thermophilic Aspergillus species were evaluated. The suitable medium and microorganisms for α-amylase synthesis were selected. Subsequently, the α-amylase activity of the microorganism was researched. In the measurements made on the 7th day of production on ...

  13. Azo dye reduction by mesophilic and thermophilic anaerobic consortia

    NARCIS (Netherlands)

    Santos, dos A.B.; Madrid, de M.P.; Stams, A.J.M.; Lier, van J.B.; Cervantes, F.J.

    2005-01-01

    The reduction of the azo dye model compounds Reactive Red 2 (RR2) and Reactive Orange 14 (RO14) by mesophilic (30 C) and thermophilic (55 C) anaerobic consortia was studied in batch assays. The contribution of fermentative and methanogenic microorganisms in both temperatures was evaluated in the

  14. Real-Time PCR Quantification and Diversity Analysis of the Functional Genes aprA and dsrA of Sulfate-Reducing Prokaryotes in Marine Sediments of the Peru Continental Margin and the Black Sea.

    Science.gov (United States)

    Blazejak, Anna; Schippers, Axel

    2011-01-01

    Sulfate-reducing prokaryotes (SRP) are ubiquitous and quantitatively important members in many ecosystems, especially in marine sediments. However their abundance and diversity in subsurface marine sediments is poorly understood. In this study, the abundance and diversity of the functional genes for the enzymes adenosine 5'-phosphosulfate reductase (aprA) and dissimilatory sulfite reductase (dsrA) of SRP in marine sediments of the Peru continental margin and the Black Sea were analyzed, including samples from the deep biosphere (ODP site 1227). For aprA quantification a Q-PCR assay was designed and evaluated. Depth profiles of the aprA and dsrA copy numbers were almost equal for all sites. Gene copy numbers decreased concomitantly with depth from around 10(8)/g sediment close to the sediment surface to less than 10(5)/g sediment at 5 mbsf. The 16S rRNA gene copy numbers of total bacteria were much higher than those of the functional genes at all sediment depths and used to calculate the proportion of SRP to the total Bacteria. The aprA and dsrA copy numbers comprised in average 0.5-1% of the 16S rRNA gene copy numbers of total bacteria in the sediments up to a depth of ca. 40 mbsf. In the zone without detectable sulfate in the pore water from about 40-121 mbsf (Peru margin ODP site 1227), only dsrA (but not aprA) was detected with copy numbers of less than 10(4)/g sediment, comprising ca. 14% of the 16S rRNA gene copy numbers of total bacteria. In this zone, sulfate might be provided for SRP by anaerobic sulfide oxidation. Clone libraries of aprA showed that all isolated sequences originate from SRP showing a close relationship to aprA of characterized species or form a new cluster with only distant relation to aprA of isolated SRP. For dsrA a high diversity was detected, even up to 121 m sediment depth in the deep biosphere.

  15. Real-time PCR quantification and diversity analysis of the functional genes aprA and dsrA of sulfate-reducing bacteria in marine sediments of the Peru continental margin and the Black Sea

    Directory of Open Access Journals (Sweden)

    Axel eSchippers

    2011-12-01

    Full Text Available A quantitative, real-time PCR (Q-PCR assay for the functional gene adenosine 5´-phosphosulfate reductase (aprA of sulfate-reducing bacteria (SRB was designed. This assay was applied together with described Q-PCR assays for dissimilatory sulfite reductase (dsrA and the 16S rRNA gene of total Bacteria to marine sediments from the Peru margin (0 – 121 meters below seafloor (mbsf and the Black Sea (0 – 6 mbsf. Clone libraries of aprA show that all isolated sequences originate from SRB showing a close relationship to aprA of characterised species or form a new cluster with only distant relation to aprA of isolated SRB. Below 40 mbsf no aprA genes could be amplified. This finding corresponds with results of the applied new Q-PCR assay for aprA. In contrast to the aprA the dsrA gene could be amplified up to sediment depths of 121 mbsf. Even in such an extreme environment a high diversity of this gene was detected. The 16S rRNA gene copy numbers of total Bacteria were much higher than those of the functional genes at all sediment depths and used to calculate the proportion of SRB to the total Bacteria. The aprA and dsrA copy numbers comprised in average 0.5 - 1 % of the 16S rRNA gene copy numbers of total Bacteria in the sediments up to a depth of ca. 40 mbsf. Depth profiles of the aprA and dsrA copy numbers were almost equal for all sites. Gene copy numbers decreased concomitantly with depth from around 108 / g sediment close to the sediment surface to less than 105 / g sediment at 5 mbsf. In the zone without detectable sulfate in the pore water from ca. 40 – 121 mbsf (Peru margin ODP site 1227, only dsrA (but not aprA was detected with copy numbers of less than 104 / g sediment, comprising ca. 14 % of the 16S rRNA gene copy numbers of total Bacteria. In this zone sulfate might be provided for SRB by anaerobic sulfide oxidation.

  16. Desulfovibrio oceani subsp. oceani sp. nov., subsp. nov. and Desulfovibrio oceani subsp. galateae subsp. nov., novel sulfate-reducing bacteria isolated from the oxygen minimum zone off the coast of Peru.

    Science.gov (United States)

    Finster, Kai W; Kjeldsen, Kasper U

    2010-03-01

    Two deltaproteobacterial sulfate reducers, designated strain I.8.1(T) and I.9.1(T), were isolated from the oxygen minimum zone water column off the coast of Peru at 400 and 500 m water depth. The strains were Gram-negative, vibrio-shaped and motile. Both strains were psychrotolerant, grew optimally at 20 degrees C at pH 7.0-8.0 and at 2.5-3.5% NaCl (w/v). The strains grew by utilizing hydrogen/acetate, C(3-4) fatty acids, amino acids and glycerol as electron acceptors for sulfate reduction. Fumarate, lactate and pyruvate supported fermentative growth. Sulfate, sulfite, thiosulfate and taurin supported growth as electron acceptors. Both strains were catalase-positive and highly oxygen-tolerant, surviving 24 days of exposure to atmospheric concentrations. MK6 was the only respiratory quinone. The most prominent cellular fatty acid was iso-17:1-omega9c (18%) for strain I.8.1(T) and iso-17:0-omega9c (14%) for strain I.9.1(T). The G+C contents of their genomic DNA were 45-46 mol%. Phylogenetic analysis of 16S rRNA and dsrAB gene sequences showed that both strains belong to the genus Desulfovibrio. Desulfovibrio acrylicus DSM 10141(T) and Desulfovibrio marinisediminis JCM 14577(T) represented their closest validly described relatives with pairwise 16S rRNA gene sequence identities of 98-99%. The level of DNA-DNA hybridization between strains I.8.1(T) and I.9.1(T) was 30-38%. The two strains shared 10-26% DNA-DNA relatedness with D. acrylicus. Based on a polyphasic investigation it is proposed that strains I.8.1(T) and I.9.1(T) represent a novel species for which the name Desulfovibrio oceani sp. nov. is proposed with the two subspecies D. oceani subsp. oceani (type strain, I.8.1(T) = DSM 21390(T) = JCM 15970(T)) and D. oceani subsp. galateae (type strain, I.9.1(T) = DSM 21391(T) = JCM 15971(T)).

  17. Survival of thermophilic and hyper-thermophilic microorganisms after exposure to UV-C, ionizing radiation and desiccation

    International Nuclear Information System (INIS)

    Beblo, K.; Wirth, R.; Huber, H.; Douki, T.; Schmalz, G.; Rachel, R.

    2011-01-01

    In this study, we investigated the ability of several (hyper-) thermophilic Archaea and phylo-genetically deep-branching thermophilic Bacteria to survive high fluences of monochromatic UV-C (254 nm) and high doses of ionizing radiation, respectively. Nine out of fourteen tested microorganisms showed a surprisingly high tolerance against ionizing radiation, and two species (Aquifex pyrophilus and Ignicoccus hospitalis) were even able to survive 20 kGy. Therefore, these species had a comparable survivability after exposure to ionizing radiation such as Deinococcus radiodurans. In contrast, there was nearly no difference in survival of the tested strains after exposure to UV-C under anoxic conditions. If the cells had been dried in advance of UV-C irradiation, they were more sensitive to UV-C radiation compared with cells irradiated in liquid suspension; this effect could be reversed by the addition of protective material like sulfidic ores before irradiation. By exposure to UV-C, photoproducts were formed in the DNA of irradiated Archaea and Bacteria. The distribution of the main photoproducts was species specific, but the amount of the photoproducts was only partly dependent on the applied fluence. Overall, our results show that tolerance to radiation seems to be a common phenomenon among thermophilic and hyper-thermophilic microorganisms. (authors)

  18. Enrichment of Thermophilic Propionate-Oxidizing Bacteria in Syntrophy with Methanobacterium thermoautotrophicum or Methanobacterium thermoformicicum

    OpenAIRE

    Stams, Alfons J. M.; Grolle, Katja C. F.; Frijters, Carla T. M.; Van Lier, Jules B.

    1992-01-01

    Thermophilic propionate-oxidizing, proton-reducing bacteria were enriched from the granular methanogenic sludge of a bench-scale upflow anaerobic sludge bed reactor operated at 55°C with a mixture of volatile fatty acids as feed. Thermophilic hydrogenotrophic methanogens had a high decay rate. Therefore, stable, thermophilic propionate-oxidizing cultures could not be obtained by using the usual enrichment procedures. Stable and reproducible cultivation was possible by enrichment in hydrogen-p...

  19. Thermophilic and unusually acidophilic amylase produced by a thermophilic acidophilic bacillus sp

    Energy Technology Data Exchange (ETDEWEB)

    Uchino, F

    1982-01-01

    Bacillus sp. 11-1S, a thermophilic acidophilic bacterial strain, produced an extracellular amylase with unusual characteristics. The enzyme was purified 40-fold by SE-Sephadex column chromatography. The pH optimum for activity was 2.0, and substantial activity was noted in the pH range of 1.5-3.5. The optimal temperature was 70 degrees C, but the activity decreased markedly in lower reaction temperatures. Arrhenius plots of the reaction showed two straight lines intersecting at about 50 degrees C. The activity or stability of the enzyme was not likely to depend on Ca2+. The molecular weight of the enzyme was 54,000 calculated from the electrophoretic mobility. The enzyme behaved like an alpha-amylase (1,4-alpha-D- glucan glucanohydrolase, E.C. 3.2.1.1). About 34% of glucosidic linkages of soluble starch was hydrolyzed at 65 degrees C and pH 2.0, in 24 hours, and the major products were maltotriose and maltose. (Refs. 14).

  20. Bioleaching of multiple metals from contaminated sediment by moderate thermophiles.

    Science.gov (United States)

    Gan, Min; Jie, Shiqi; Li, Mingming; Zhu, Jianyu; Liu, Xinxing

    2015-08-15

    A moderately thermophilic consortium was applied in bioleaching multiple metals from contaminated sediment. The consortium got higher acidification and metals soubilization efficiency than that of the pure strains. The synergistic effect of the thermophilic consortium accelerated substrates utilization. The utilization of substrate started with sulfur in the early stage, and then the pH declined, giving rise to making use of the pyrite. Community dynamic showed that A. caldus was the predominant bacteria during the whole bioleaching process while the abundance of S. thermotolerans increased together with pyrite utilization. Solubilization efficiency of Zn, Cu, Mn and Cd reached 98%, 94%, 95%, and 89% respectively, while As, Hg, Pb was only 45%, 34%, 22%. Logistic model was used to simulate the bioleaching process, whose fitting degree was higher than 90%. Correlation analysis revealed that metal leaching was mainly an acid solubilization process. Fraction analysis revealed that metals decreased in mobility and bioavailability. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. [Conversion of acetic acid to methane by thermophiles

    Energy Technology Data Exchange (ETDEWEB)

    Zinder, S.H.

    1993-01-01

    The primary goal of this project is to obtain a better understanding of thermophilic microorganisms which convert acetic acid to CH[sub 4]. The previous funding period represents a departure from earlier research in this laboratory, which was more physiological and ecological. The present work is centered on the biochemistry of the thermophile Methanothrix sp. strain CALS-1. this organism presents a unique opportunity, with its purity and relatively rapid growth, to do comparative biochemical studies with the other major acetotrophic genus Methanosarcina. We previously found that Methanothrix is capable of using acetate at concentrations 100 fold lower than Methanosarcina. This finding suggests that there are significant differences in the pathways of methanogenesis from acetate in the two genera.

  2. Structural and physicochemical properties of polar lipids from thermophilic archaea.

    Science.gov (United States)

    Ulrih, Natasa Poklar; Gmajner, Dejan; Raspor, Peter

    2009-08-01

    The essential general features required for lipid membranes of extremophilic archaea to fulfill biological functions are that they are in the liquid crystalline phase and have extremely low permeability of solutes that is much less temperature sensitive due to a lack of lipid-phase transition and highly branched isoprenoid chains. Many accumulated data indicate that the organism's response to extremely low pH is the opposite of that to high temperature. The high temperature adaptation does not require the tetraether lipids, while the adaptation of thermophiles to acidic environment requires the tetraether polar lipids. The presence of cyclopentane rings and the role of polar heads are not so straightforward regarding the correlations between fluidity and permeability of the lipid membrane. Due to the unique lipid structures and properties of archaeal lipids, they are a valuable resource in the development of novel biotechnological processes. This microreview focuses primarily on structural and physicochemical properties of polar lipids of (hyper)thermophilic archaea.

  3. Widespread Disulfide Bonding in Proteins from Thermophilic Archaea

    Directory of Open Access Journals (Sweden)

    Julien Jorda

    2011-01-01

    Full Text Available Disulfide bonds are generally not used to stabilize proteins in the cytosolic compartments of bacteria or eukaryotic cells, owing to the chemically reducing nature of those environments. In contrast, certain thermophilic archaea use disulfide bonding as a major mechanism for protein stabilization. Here, we provide a current survey of completely sequenced genomes, applying computational methods to estimate the use of disulfide bonding across the Archaea. Microbes belonging to the Crenarchaeal branch, which are essentially all hyperthermophilic, are universally rich in disulfide bonding while lesser degrees of disulfide bonding are found among the thermophilic Euryarchaea, excluding those that are methanogenic. The results help clarify which parts of the archaeal lineage are likely to yield more examples and additional specific data on protein disulfide bonding, as increasing genomic sequencing efforts are brought to bear.

  4. Widespread disulfide bonding in proteins from thermophilic archaea.

    Science.gov (United States)

    Jorda, Julien; Yeates, Todd O

    2011-01-01

    Disulfide bonds are generally not used to stabilize proteins in the cytosolic compartments of bacteria or eukaryotic cells, owing to the chemically reducing nature of those environments. In contrast, certain thermophilic archaea use disulfide bonding as a major mechanism for protein stabilization. Here, we provide a current survey of completely sequenced genomes, applying computational methods to estimate the use of disulfide bonding across the Archaea. Microbes belonging to the Crenarchaeal branch, which are essentially all hyperthermophilic, are universally rich in disulfide bonding while lesser degrees of disulfide bonding are found among the thermophilic Euryarchaea, excluding those that are methanogenic. The results help clarify which parts of the archaeal lineage are likely to yield more examples and additional specific data on protein disulfide bonding, as increasing genomic sequencing efforts are brought to bear.

  5. Evolvability of thermophilic proteins from archaea and bacteria.

    Science.gov (United States)

    Takano, Kazufumi; Aoi, Atsushi; Koga, Yuichi; Kanaya, Shigenori

    2013-07-16

    Proteins from thermophiles possess high thermostability. The stabilization mechanisms differ between archaeal and bacterial proteins, whereby archaeal proteins are mainly stabilized via hydrophobic interactions and bacterial proteins by ion pairs. High stability is an important factor in promoting protein evolution, but the precise means by which different stabilization mechanisms affect the evolution process remain unclear. In this study, we investigated a random mutational drift of esterases from thermophilic archaea and bacteria at high temperatures. Our results indicate that mutations in archaeal proteins lead to improved function with no loss of stability, while mutant bacterial proteins are largely destabilized with decreased activity at high temperatures. On the basis of these findings, we suggest that archaeal proteins possess higher "evolvability" than bacterial proteins under temperature selection and are additionally able to evolve into eukaryotic proteins.

  6. Gas Fermentation using Thermophilic Moorella Species for production of Biochemicals

    DEFF Research Database (Denmark)

    Redl, Stephanie Maria Anna

    Gas fermentation is a promising technology which gained increasing attention over the last years. In this process, acetogenic bacteria convert gases rich in H2, CO2, and CO, into compounds of higher value. The gas can derive from industrial off-gas or from waste streams via gasification. In the gas...... fermentation processes that are nearly on commercial level, mesophilic acetogens are used to mainly produce ethanol and butanediol. However, thermophilic acetogens, such as Moorella thermoacetica would allow for easy downstream processing when producing volatile products such as acetone. This thesis starts...... with a review of the feedstock potential for gas fermentation and how thermophilic production strains as well as unconventional fermentation processes such as mixotrophy can help to exploit this potential. I analyzed a process with respect to thermodynamic and economic considerations, in which acetone...

  7. Chlorophyll a with a farnesyl tail in thermophilic cyanobacteria.

    Science.gov (United States)

    Wiwczar, Jessica M; LaFountain, Amy M; Wang, Jimin; Frank, Harry A; Brudvig, Gary W

    2017-11-01

    Photosystem II (PSII) of oxygenic photosynthetic organisms normally contains exclusively chlorophyll a (Chl a) as its major light-harvesting pigment. Chl a canonically consists of the chlorin headgroup with a 20-carbon, 4-isoprene unit, phytyl tail. We have examined the 1.9 Å crystal structure of PSII from thermophilic cyanobacteria reported by Shen and coworkers in 2012 (PDB accession of 3ARC/3WU2). A newly refined electron density map from this structure, presented here, reveals that some assignments of the cofactors may be different from those modeled in the 3ARC/3WU2 structure, including a specific Chl a that appears to have a truncated tail by one isoprene unit. We provide experimental evidence using high-performance liquid chromatography and mass spectrometry for a small population of Chl a esterified to a 15-carbon farnesyl tail in PSII of thermophilic cyanobacteria.

  8. Production of Bioethanol From Lignocellulosic Biomass Using Thermophilic Anaerobic Bacteria

    DEFF Research Database (Denmark)

    Georgieva, Tania I.

    2006-01-01

    and xylose and to tolerate the inhibitory compounds present in lignocellulosic hydrolysates is therefore apparent. Several thermophilic anaerobic xylan degrading bacteria from our culture collection (EMB group at BioCentrum-DTU) have been screened for a potential ethanol producer from hemicellulose...... hydrolysates, and out of the screening test, one particular strain (A10) was selected for the best performance. The strain was morphologically and physiologically characterized as Thermoanaerobacter mathranii strain A10. Unlike other thermophilic anaerobic bacteria, the wild-type strain Thermoanaerobacter...... Thermoanaerobacter BG1L1 was further studied. The experiments were carried out in a continuous immobilized reactor system (a fluidized bed reactor), which is likely to be the process design configuration for xylose fermentation in a Danish biorefinery concept for production of fuel ethanol. The immobilization...

  9. Startup and stability of thermophilic anaerobic digestion of OFMSW

    KAUST Repository

    El-Fadel, Mutasem E.; Saikaly, Pascal; Ghanimeh, Sophia A.

    2013-01-01

    Anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) is promoted as an energy source and more recently as a greenhouse gas (GHG) mitigation measure. In this context, AD systems operating at thermophilic temperatures (55-60°C)-compared to mesophilic temperatures (35-40°C)-have the unique feature of producing hygienic soil conditioners with greater process efficiency, higher energy yield, and more GHG savings. Startup of AD systems is often constrained by the lack of acclimated seeds, leading to process instability and failure. The authors focus on strategies to startup thermophilic digesters treating OFMSW in the absence of acclimated seeds and examines constraints associated with process stability and ways to overcome them. Relevant gaps in the literature and future research needs are delineated. © 2013 Taylor & Francis Group, LLC.

  10. Thermophilic anaerobic acetate-utilizing methanogens and their metabolism

    DEFF Research Database (Denmark)

    Mladenovska, Zuzana

    Six strains of thermophilic anaerobic acetate-utilizing methanogens were isolated from different full-scale thermophilic biogas plants in China and Denmark. The strain isolated from the Chinese biogas plant was designated KN-6P and the isolates from the Danish full-scale biogas plants were......, utilizing the substrates acetate, methanol and methylamines but not hydrogen/carbon dioxide. Strain Methanosarcina sp. SO-2P was able to grow mixotrophically on methanol and hydrogen/carbon dioxide with methane formation from hydrogen and carbon dioxide occurring after methanol depletion. All six...... designated HG-1P, LVG-4P R1-1P, SO-2P and V-1P. The isolates were characterized morphologically and physiologically, and their immunological and phylogenetic relatedness to already known isolated strains were established. All isolated strains were identified as organisms belonging to genus Methanosarcina...

  11. Sequential Detection of Thermophilic Lipase and Protease by Zymography.

    Science.gov (United States)

    Kurz, Liliana; Hernández, Zully; Contreras, Lellys M; Wilkesman, Jeff

    2017-01-01

    Lipase and protease present in cell-free fractions of thermophilic Bacillus sp. cultures were analyzed by polyacrylamide gel (PAG) electrophoresis. After run, the gel is electrotransferred to another PAG copolymerized with glycerol tributyrate, olive oil, and gelatin. This multi-substrate gel was incubated first for lipase detection, until bands appeared, and then stained with Coomassie for protease detection. Advantages of this sequential procedure are the detection of two different enzyme activities on a single PAG, beside time and resource saving.

  12. Widespread Disulfide Bonding in Proteins from Thermophilic Archaea

    OpenAIRE

    Jorda, Julien; Yeates, Todd O.

    2011-01-01

    Disulfide bonds are generally not used to stabilize proteins in the cytosolic compartments of bacteria or eukaryotic cells, owing to the chemically reducing nature of those environments. In contrast, certain thermophilic archaea use disulfide bonding as a major mechanism for protein stabilization. Here, we provide a current survey of completely sequenced genomes, applying computational methods to estimate the use of disulfide bonding across the Archaea. Microbes belonging to the Crenarchaea...

  13. Extremely thermophilic microorganisms for biomass conversion: status and prospects.

    Science.gov (United States)

    Blumer-Schuette, Sara E; Kataeva, Irina; Westpheling, Janet; Adams, Michael Ww; Kelly, Robert M

    2008-06-01

    Many microorganisms that grow at elevated temperatures are able to utilize a variety of carbohydrates pertinent to the conversion of lignocellulosic biomass to bioenergy. The range of substrates utilized depends on growth temperature optimum and biotope. Hyperthermophilic marine archaea (T(opt)>or=80 degrees C) utilize alpha- and beta-linked glucans, such as starch, barley glucan, laminarin, and chitin, while hyperthermophilic marine bacteria (T(opt)>or=80 degrees C) utilize the same glucans as well as hemicellulose, such as xylans and mannans. However, none of these organisms are able to efficiently utilize crystalline cellulose. Among the thermophiles, this ability is limited to a few terrestrial bacteria with upper temperature limits for growth near 75 degrees C. Deconstruction of crystalline cellulose by these extreme thermophiles is achieved by 'free' primary cellulases, which are distinct from those typically associated with large multi-enzyme complexes known as cellulosomes. These primary cellulases also differ from the endoglucanases (referred to here as 'secondary cellulases') reported from marine hyperthermophiles that show only weak activity toward cellulose. Many extremely thermophilic enzymes implicated in the deconstruction of lignocellulose can be identified in genome sequences, and many more promising biocatalysts probably remain annotated as 'hypothetical proteins'. Characterization of these enzymes will require intensive effort but is likely to generate new opportunities for the use of renewable resources as biofuels.

  14. Genetic Tools and Techniques for Recombinant Expression in Thermophilic Bacillaceae

    Directory of Open Access Journals (Sweden)

    Eivind B. Drejer

    2018-05-01

    Full Text Available Although Escherichia coli and Bacillus subtilis are the most prominent bacterial hosts for recombinant protein production by far, additional species are being explored as alternatives for production of difficult-to-express proteins. In particular, for thermostable proteins, there is a need for hosts able to properly synthesize, fold, and excrete these in high yields, and thermophilic Bacillaceae represent one potentially interesting group of microorganisms for such purposes. A number of thermophilic Bacillaceae including B. methanolicus, B. coagulans, B. smithii, B. licheniformis, Geobacillus thermoglucosidasius, G. kaustophilus, and G. stearothermophilus are investigated concerning physiology, genomics, genetic tools, and technologies, altogether paving the way for their utilization as hosts for recombinant production of thermostable and other difficult-to-express proteins. Moreover, recent successful deployments of CRISPR/Cas9 in several of these species have accelerated the progress in their metabolic engineering, which should increase their attractiveness for future industrial-scale production of proteins. This review describes the biology of thermophilic Bacillaceae and in particular focuses on genetic tools and methods enabling use of these organisms as hosts for recombinant protein production.

  15. Potential and utilization of thermophiles and thermostable enzymes in biorefining

    Directory of Open Access Journals (Sweden)

    Karlsson Eva

    2007-03-01

    Full Text Available Abstract In today's world, there is an increasing trend towards the use of renewable, cheap and readily available biomass in the production of a wide variety of fine and bulk chemicals in different biorefineries. Biorefineries utilize the activities of microbial cells and their enzymes to convert biomass into target products. Many of these processes require enzymes which are operationally stable at high temperature thus allowing e.g. easy mixing, better substrate solubility, high mass transfer rate, and lowered risk of contamination. Thermophiles have often been proposed as sources of industrially relevant thermostable enzymes. Here we discuss existing and potential applications of thermophiles and thermostable enzymes with focus on conversion of carbohydrate containing raw materials. Their importance in biorefineries is explained using examples of lignocellulose and starch conversions to desired products. Strategies that enhance thermostablity of enzymes both in vivo and in vitro are also assessed. Moreover, this review deals with efforts made on developing vectors for expressing recombinant enzymes in thermophilic hosts.

  16. Hydrophobic environment is a key factor for the stability of thermophilic proteins.

    Science.gov (United States)

    Gromiha, M Michael; Pathak, Manish C; Saraboji, Kadhirvel; Ortlund, Eric A; Gaucher, Eric A

    2013-04-01

    The stability of thermophilic proteins has been viewed from different perspectives and there is yet no unified principle to understand this stability. It would be valuable to reveal the most important interactions for designing thermostable proteins for such applications as industrial protein engineering. In this work, we have systematically analyzed the importance of various interactions by computing different parameters such as surrounding hydrophobicity, inter-residue interactions, ion-pairs and hydrogen bonds. The importance of each interaction has been determined by its predicted relative contribution in thermophiles versus the same contribution in mesophilic homologues based on a dataset of 373 protein families. We predict that hydrophobic environment is the major factor for the stability of thermophilic proteins and found that 80% of thermophilic proteins analyzed showed higher hydrophobicity than their mesophilic counterparts. Ion pairs, hydrogen bonds, and interaction energy are also important and favored in 68%, 50%, and 62% of thermophilic proteins, respectively. Interestingly, thermophilic proteins with decreased hydrophobic environments display a greater number of hydrogen bonds and/or ion pairs. The systematic elimination of mesophilic proteins based on surrounding hydrophobicity, interaction energy, and ion pairs/hydrogen bonds, led to correctly identifying 95% of the thermophilic proteins in our analyses. Our analysis was also applied to another, more refined set of 102 thermophilic-mesophilic pairs, which again identified hydrophobicity as a dominant property in 71% of the thermophilic proteins. Further, the notion of surrounding hydrophobicity, which characterizes the hydrophobic behavior of residues in a protein environment, has been applied to the three-dimensional structures of elongation factor-Tu proteins and we found that the thermophilic proteins are enriched with a hydrophobic environment. The results obtained in this work highlight the

  17. Sulfate reduction with methanol by a thermophilic consortium obtained from a methanogenic reactor

    Energy Technology Data Exchange (ETDEWEB)

    Davidova, I.A. [Wageningen Agricultural Univ. (Netherlands). Dept. of Microbiology; Stams, A.J.M. [Wageningen Agricultural Univ. (Netherlands). Dept. of Microbiology

    1996-12-31

    An enrichment culture obtained from anaerobic granular sludge of a bench-scale anarobic reactor degraded methanol at 65 C via sulfate reduction and acetogenesis. Sulfate reduction was the dominant process (S{sup 2-}/acetate=2.5). No methane formation was observed. Approximately 30% of the methanol was converted by acetogenic bacteria to acetate, while the remainder was degraded by these bacteria to H{sub 2} and CO{sub 2} in syntrophy with hydrogen-consuming sulfate-reducing bacteria. Pure cultures of sulfate-reducing and acetogenic bacteria were isolated and characterized. (orig.)

  18. A family 5 β-mannanase from the thermophilic fungus Thielavia arenaria XZ7 with typical thermophilic enzyme features.

    Science.gov (United States)

    Lu, Haiqiang; Zhang, Huitu; Shi, Pengjun; Luo, Huiying; Wang, Yaru; Yang, Peilong; Yao, Bin

    2013-09-01

    A novel β-mannanase gene, man5XZ7, was cloned from thermophilic fungus Thielavia arenaria XZ7, and successfully expressed in Pichia pastoris. The gene (1,110 bp) encodes a 369-amino acid polypeptide with a molecular mass of approximately 40.8 kDa. The deduced sequence of Man5XZ7 consists of a putative 17-residue signal peptide and a catalytic module belonging to glycoside hydrolase (GH) family 5, and displays 76 % identity with the experimentally verified GH 5 endo-β-1,4-mannanase from Podospora anserina. Recombinant Man5XZ7 was optimally active at 75 °C and pH 5.0 and exhibited high activity at a wide temperature range (>50.0 % activity at 50-85 °C). Moreover, it had good adaptability to acidic to basic pH (>74.1 % activity at pH 4.0-7.0 and 25.6 % even at pH 9.0) and good stability from pH 3.0 to 10.0. These enzymatic properties showed that Man5XZ7 was a new thermophilic and alkali-tolerant β-mannanase. Further amino acid composition analysis indicated that Man5XZ7 has several characteristic features of thermophilic enzymes.

  19. Methanomethylovorans thermophila sp. nov., a thermophilic, methylotrophic methanogen form an anaerobic reactor fed with methanol

    NARCIS (Netherlands)

    Jiang, B.; Parshina, S.N.; Doesburg, van W.C.J.; Lomans, B.P.; Stams, A.J.M.

    2005-01-01

    A novel thermophilic, obligately methylotrophic, methanogenic archaeon, strain L2FAWT, was isolated from a thermophilic laboratory-scale upflow anaerobic sludge blanket reactor fed with methanol as the carbon and energy source. Cells of strain L2FAWT were non-motile, irregular cocci, 0·7¿1·5 µm in

  20. Mesophilic and thermophilic activated sludge post-treatment of paper mill process water

    NARCIS (Netherlands)

    Vogelaar, J.C.T.; Bouwhuis, E.; Klapwijk, A.; Spanjers, H.; Lier, van J.B.

    2002-01-01

    Increasing system closure in paper mills and higher process water temperatures make the applicability of thermophilic treatment systems increasingly important. The use of activated sludge as a suitable thermophilic post-treatment system for anaerobically pre-treated paper process water from a paper

  1. Supplement to thermophilic hydrolysis of liquid manures. Bilag til termofil hydrolyse af gylle

    Energy Technology Data Exchange (ETDEWEB)

    1990-07-01

    A supplement to ''Thermophilic hydrolysis of liquid manures'' which contains descriptions of testing methods and results for determining the influence of additives such as propionic acid or triolein on chemical reactions in connection with the decomposition of liquid manures under thermophilic conditions. (AB).

  2. Efficient Genome Editing of a Facultative Thermophile Using Mesophilic spCas9

    NARCIS (Netherlands)

    Mougiakos, Ioannis; Bosma, Elleke F.; Weenink, Koen; Vossen, Eric; Goijvaerts, Kirsten; Oost, van der John; Kranenburg, van Richard

    2017-01-01

    Well-developed genetic tools for thermophilic microorganisms are scarce, despite their industrial and scientific relevance. Whereas highly efficient CRISPR/Cas9-based genome editing is on the rise in prokaryotes, it has never been employed in a thermophile. Here, we apply Streptococcus pyogenes

  3. State of the art and future perspectives of thermophilic anaerobic digestion

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær; Mladenovska, Zuzana; Iranpour, R.

    2002-01-01

    The slate of the art of thermophilic digestion is discussed. Thermophilic digestion is a well established technology in Europe for treatment of mixtures of waste in common large scale biogas plants or for treatment of the organic fraction of municipal solid waste. Due to a large number of failures...... over time with thermophilic digestion of sewage sludge this process has lost its appeal in the USA. New demands on sanitation of biosolids before land use will, however, bring the attention back to the use of elevated temperatures during sludge stabilization. In the paper we show how the use of a start......-up strategy based on the actual activity of key microbes can be used to ensure proper and fast transfer of mesophilic digesters into thermophilic operation. Extreme thermophilic temperatures of 65degreesC or more may be necessary in the future to meet the demands for full sanitation of the waste material...

  4. Comparative genomic analysis of the thermophilic biomass-degrading fungi Myceliophthora thermophila and Thielavia terrestris

    Energy Technology Data Exchange (ETDEWEB)

    Berka, Randy M.; Grigoriev, Igor V.; Otillar, Robert; Salamov, Asaf; Grimwood, Jane; Reid, Ian; Ishmael, Nadeeza; John, Tricia; Darmond, Corinne; Moisan, Marie-Claude; Henrissat, Bernard; Coutinho, Pedro M.; Lombard, Vincent; Natvig, Donald O.; Lindquist, Erika; Schmutz, Jeremy; Lucas, Susan; Harris, Paul; Powlowski, Justin; Bellemare, Annie; Taylor, David; Butler, Gregory; de Vries, Ronald P.; Allijn, Iris E.; van den Brink, Joost; Ushinsky, Sophia; Storms, Reginald; Powell, Amy J.; Paulsen, Ian T.; Elbourne, Liam D. H.; Baker, Scott. E.; Magnuson, Jon; LaBoissiere, Sylvie; Clutterbuck, A. John; Martinez, Diego; Wogulis, Mark; Lopez de Leon, Alfredo; Rey, Michael W.; Tsang, Adrian

    2011-05-16

    Thermostable enzymes and thermophilic cell factories may afford economic advantages in the production of many chemicals and biomass-based fuels. Here we describe and compare the genomes of two thermophilic fungi, Myceliophthora thermophila and Thielavia terrestris. To our knowledge, these genomes are the first described for thermophilic eukaryotes and the first complete telomere-to-telomere genomes for filamentous fungi. Genome analyses and experimental data suggest that both thermophiles are capable of hydrolyzing all major polysaccharides found in biomass. Examination of transcriptome data and secreted proteins suggests that the two fungi use shared approaches in the hydrolysis of cellulose and xylan but distinct mechanisms in pectin degradation. Characterization of the biomass-hydrolyzing activity of recombinant enzymes suggests that these organisms are highly efficient in biomass decomposition at both moderate and high temperatures. Furthermore, we present evidence suggesting that aside from representing a potential reservoir of thermostable enzymes, thermophilic fungi are amenable to manipulation using classical and molecular genetics.

  5. Rapid establishment of thermophilic anaerobic microbial community during the one-step startup of thermophilic anaerobic digestion from a mesophilic digester.

    Science.gov (United States)

    Tian, Zhe; Zhang, Yu; Li, Yuyou; Chi, Yongzhi; Yang, Min

    2015-02-01

    The purpose of this study was to explore how fast the thermophilic anaerobic microbial community could be established during the one-step startup of thermophilic anaerobic digestion from a mesophilic digester. Stable thermophilic anaerobic digestion was achieved within 20 days from a mesophilic digester treating sewage sludge by adopting the one-step startup strategy. The succession of archaeal and bacterial populations over a period of 60 days after the temperature increment was followed by using 454-pyrosequencing and quantitative PCR. After the increase of temperature, thermophilic methanogenic community was established within 11 days, which was characterized by the fast colonization of Methanosarcina thermophila and two hydrogenotrophic methanogens (Methanothermobacter spp. and Methanoculleus spp.). At the same time, the bacterial community was dominated by Fervidobacterium, whose relative abundance rapidly increased from 0 to 28.52 % in 18 days, followed by other potential thermophilic genera, such as Clostridium, Coprothermobacter, Anaerobaculum and EM3. The above result demonstrated that the one-step startup strategy could allow the rapid establishment of the thermophilic anaerobic microbial community. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Energetic and hydrogen limitations of thermophilic and hyperthermophilic methanogens

    Science.gov (United States)

    Stewart, L. C.; Holden, J. F.

    2013-12-01

    Deep-sea hydrothermal vents are a unique ecosystem, based ultimately not on photosynthesis but chemosynthetic primary production. This makes them an excellent analog environment for the early Earth, and for potential extraterrestrial habitable environments, such as those on Mars and Europa. The habitability of given vent systems for chemoautotrophic prokaryotes can be modeled energetically by estimating the available Gibbs energy for specific modes of chemoautotrophy, using geochemical data and mixing models for hydrothermal fluids and seawater (McCollom and Shock, 1997). However, modeling to date has largely not taken into account variation in organisms' energy demands in these environments. Controls on maintenance energies are widely assumed to be temperature-dependent, rising with increasing temperature optima (Tijhuis et al., 1993), and species-independent. The impacts of other environmental stressors and particular energy-gathering strategies on maintenance energies have not been investigated. We have undertaken culture-based studies of growth and maintenance energies in thermophilic and hyperthermophilic methanogenic (hydrogenotrophic) archaea from deep-sea hydrothermal vents to investigate potential controls on energy demands in hydrothermal vent microbes, and to quantify their growth and maintenance energies for future bioenergetic modeling. We have investigated trends in their growth energies over their full temperature range and a range of nitrogen concentrations, and in their maintenance energies at different hydrogen concentrations. Growth energies in these organisms appear to rise with temperature, but do not vary between hyperthermophilic and thermophilic methanogens. Nitrogen availability at tested levels (40μM - 9.4 mM) does not appear to affect growth energies in all but one tested organism. In continuous chemostat culture, specific methane production varied with hydrogen availability but was similar between a thermophilic and a hyperthermophilic

  7. Thermophilic and alkaliphilic Actinobacteria: Biology and potential applications

    Directory of Open Access Journals (Sweden)

    L eShivlata

    2015-09-01

    Full Text Available Microbes belonging to the phylum Actinobacteria are prolific sources of antibiotics, clinically useful bioactive compounds and industrially important enzymes. The focus of the current review is on the diversity and potential applications of thermophilic and alkaliphilic actinobacteria, which are highly diverse in their taxonomy and morphology with a variety of adaptations for surviving and thriving in hostile environments. The specific metabolic pathways in these actinobacteria are activated for elaborating pharmaceutically, agriculturally and biotechnologically relevant biomolecules/bioactive compounds, which find multifarious applications.

  8. Extremely thermophilic microorganisms and their polymer-hidrolytic enzymes

    Directory of Open Access Journals (Sweden)

    Andrade Carolina M.M.C.

    1999-01-01

    Full Text Available Thermophilic and hyperthermophilic microorganisms are found as normal inhabitants of continental and submarine volcanic areas, geothermally heated sea-sediments and hydrothermal vents and thus are considered extremophiles. Several present or potential applications of extremophilic enzymes are reviewed, especially polymer-hydrolysing enzymes, such as amylolytic and hemicellulolytic enzymes. The purpose of this review is to present the range of morphological and metabolic features among those microorganisms growing from 70oC to 100°C and to indicate potential opportunities for useful applications derived from these features.

  9. Thermophilic and alkaliphilic Actinobacteria: biology and potential applications

    Science.gov (United States)

    Shivlata, L.; Satyanarayana, Tulasi

    2015-01-01

    Microbes belonging to the phylum Actinobacteria are prolific sources of antibiotics, clinically useful bioactive compounds and industrially important enzymes. The focus of the current review is on the diversity and potential applications of thermophilic and alkaliphilic actinobacteria, which are highly diverse in their taxonomy and morphology with a variety of adaptations for surviving and thriving in hostile environments. The specific metabolic pathways in these actinobacteria are activated for elaborating pharmaceutically, agriculturally, and biotechnologically relevant biomolecules/bioactive compounds, which find multifarious applications. PMID:26441937

  10. Comparative study in the induced corrosion by sulfate reducing microorganisms, in a stainless steel 304L sensitized and a carbon steel API X65; Estudio comparativo de la corrosion inducida por microorganismos sulfatorreductores, en un acero inoxidable 304L sensibilizado y un acero al carbono API X65

    Energy Technology Data Exchange (ETDEWEB)

    Diaz S, A.; Gonzalez F, E.; Arganis J, C.; Luna C, P.; Carapia M, L. [ININ, Carretera Mexico-Toluca Km. 36.5, 52045 Estado de Mexico (Mexico)]. e-mail: ads@nuclear.inin.mx

    2004-07-01

    In spite of the operational experience related with the presence of the phenomenon of microbiological corrosion (MIC) in industrial components, it was not but until the decade of the 80 s when the nuclear industry recognized its influence in some systems of Nuclear Generating Power plants. At the moment, diverse studies that have tried to explain the generation mechanism of this phenomenon exist; however, they are even important queries that to solve, especially those related with the particularities of the affected metallic substrates. Presently work, the electrochemical behavior of samples of stainless steel AISI 304L sensitized is evaluated and the carbon steel APIX65, before the action of sulfate reducing microorganisms low the same experimental conditions; found that for the APIX65 the presence of this type of bacteria promoted the formation of a stable biofilm that allowed the maintenance of the microorganisms that damaged the material in isolated places where stings were generated; while in the AISI 304L, it was not detected damage associated to the inoculated media. The techniques of Resistance to the Polarization and Tafel Extrapolation, allowed the calculation of the speed of uniform corrosion, parameter that doesn't seem to be influenced by the presence of the microorganisms; while that noise electrochemical it distinguished in real time, the effect of the sulfate reducing in the steel APIX65. (Author)

  11. Biomass production and energy source of thermophiles in a Japanese alkaline geothermal pool.

    Science.gov (United States)

    Kimura, Hiroyuki; Mori, Kousuke; Nashimoto, Hiroaki; Hattori, Shohei; Yamada, Keita; Koba, Keisuke; Yoshida, Naohiro; Kato, Kenji

    2010-02-01

    Microbial biomass production has been measured to investigate the contribution of planktonic bacteria to fluxations in dissolved organic matter in marine and freshwater environments, but little is known about biomass production of thermophiles inhabiting geothermal and hydrothermal regions. The biomass production of thermophiles inhabiting an 85 degrees C geothermal pool was measured by in situ cultivation using diffusion chambers. The thermophiles' growth rates ranged from 0.43 to 0.82 day(-1), similar to those of planktonic bacteria in marine and freshwater habitats. Biomass production was estimated based on cellular carbon content measured directly from the thermophiles inhabiting the geothermal pool, which ranged from 5.0 to 6.1 microg C l(-1) h(-1). This production was 2-75 times higher than that of planktonic bacteria in other habitats, because the cellular carbon content of the thermophiles was much higher. Quantitative PCR and phylogenetic analysis targeting 16S rRNA genes revealed that thermophilic H2-oxidizing bacteria closely related to Calderobacterium and Geothermobacterium were dominant in the geothermal pool. Chemical analysis showed the presence of H2 in gases bubbling from the bottom of the geothermal pool. These results strongly suggested that H2 plays an important role as a primary energy source of thermophiles in the geothermal pool.

  12. Relationship between microbial community dynamics and process performance during thermophilic sludge bioleaching.

    Science.gov (United States)

    Chen, Shen-Yi; Chou, Li-Chieh

    2016-08-01

    Heavy metals can be removed from the sludge using bioleaching technologies at thermophilic condition, thereby providing an option for biotreatment of wasted sludge generated from wastewater treatment. The purposes of this study were to establish a molecular biology technique, real-time PCR, for the detection and enumeration of the sulfur-oxidizing bacteria during the thermophilic sludge bioleaching. The 16S rRNA gene for real-time PCR quantification targeted the bioleaching bacteria: Sulfobacillus thermosulfidooxidans, Sulfobacillus acidophilus, and Acidithiobacillus caldus. The specificity and stringency for thermophilic sulfur-oxidizing bacteria were tested before the experiments of monitoring the bacterial community, bacterial number during the thermophilic sludge bioleaching and the future application on testing various environmental samples. The results showed that S. acidophilus was identified as the dominant sulfur-oxidizing bacteria, while A. caldus and S. thermosulfidooxidans occurred in relatively low numbers. The total number of the sulfur-oxidizing bacteria increased during the thermophilic bioleaching process. Meanwhile, the decrease of pH, production of sulfate, degradation of SS/VSS, and solubilization of heavy metal were found to correlate well with the population of thermophilic sulfur-oxidizing bacteria during the bioleaching process. The real-time PCR used in this study is a suitable method to monitor numbers of thermophilic sulfur-oxidizing bacteria during the bioleaching process.

  13. ANAEROBIC BIODEGRADATION OF A BIODEGRADABLE MATERIAL UNDER ANAEROBIC - THERMOPHILIC DIGESTION

    Directory of Open Access Journals (Sweden)

    RICARDO CAMACHO-MUÑOZ

    2014-12-01

    Full Text Available This paper dertermined the anaerobic biodegradation of a polymer obtained by extrusion process of native cassava starch, polylactic acid and polycaprolactone. Initially a thermophilic - methanogenic inoculum was prepared from urban solid waste. The gas final methane concentration and medium’s pH reached values of 59,6% and 7,89 respectively. The assay assembly was carried out according ASTM D5511 standard. The biodegradation percent of used materials after 15 day of digestion were: 77,49%, 61,27%, 0,31% for cellulose, sample and polyethylene respectively. Due cellulose showed biodegradation levels higher than 70% it’s deduced that the inoculum conditions were appropriate. A biodegradation level of 61,27%, 59,35% of methane concentration in sample’s evolved gas and a medium’s finale pH of 7,71 in sample’s vessels, reveal the extruded polymer´s capacity to be anaerobically degraded under thermophilic- high solid concentration conditions.

  14. Thermophilic and alkalophilic xylanases from several Dictyoglomus isolates

    Energy Technology Data Exchange (ETDEWEB)

    Mathrani, I M; Ahring, B K [Technical Univ. of Denmark, Lyngby (Denmark). Anaerobic Microbiology/Biotechnology Group

    1992-10-01

    Supernatant xylanases from three thermophilic and strictly anaerobic Dictyoglomus strains isolated from very different environments were examined: The type species, D. thermophilum[sup T], from a hot-spring in Japan; strain B1, a recently described strictly xylanutilizing Dictyoglomus from a paper-pulp factory in Finland; and strain B4a, isolated from a thermal pool on Iceland. The highest enzymatic activity observed from batch-culture supernatant with 4 g l[sup -1] of beech xylan as growth substrate was 3.8x10[sup -6] kat l[sup -1]. The K[sub m] for the xylanases of strain B1 was 4.7 g beech xylan l[sup -1]. The xylanases of all the isolates had a broad range of activity with respect to pH, showing good activity from pH 5.5 to near 9.0. The xylanases from the three isolates had a very high temperature optimum of 80deg C, maximum temperature for extended activity between 80 and 90deg C, and a thermal half-life of over 1 h at 90deg C for strain B1. The application of thermophilic alkalophilic xylanases to paper pulping was discussed. (orig.).

  15. Enzyme dynamics and hydrogen tunnelling in a thermophilic alcohol dehydrogenase

    Science.gov (United States)

    Kohen, Amnon; Cannio, Raffaele; Bartolucci, Simonetta; Klinman, Judith P.; Klinman, Judith P.

    1999-06-01

    Biological catalysts (enzymes) speed up reactions by many orders of magnitude using fundamental physical processes to increase chemical reactivity. Hydrogen tunnelling has increasingly been found to contribute to enzyme reactions at room temperature. Tunnelling is the phenomenon by which a particle transfers through a reaction barrier as a result of its wave-like property. In reactions involving small molecules, the relative importance of tunnelling increases as the temperature is reduced. We have now investigated whether hydrogen tunnelling occurs at elevated temperatures in a biological system that functions physiologically under such conditions. Using a thermophilic alcohol dehydrogenase (ADH), we find that hydrogen tunnelling makes a significant contribution at 65°C this is analogous to previous findings with mesophilic ADH at 25°C ( ref. 5). Contrary to predictions for tunnelling through a rigid barrier, the tunnelling with the thermophilic ADH decreases at and below room temperature. These findings provide experimental evidence for a role of thermally excited enzyme fluctuations in modulating enzyme-catalysed bond cleavage.

  16. Efficient plant biomass degradation by thermophilic fungus Myceliophthora heterothallica.

    Science.gov (United States)

    van den Brink, Joost; van Muiswinkel, Gonny C J; Theelen, Bart; Hinz, Sandra W A; de Vries, Ronald P

    2013-02-01

    Rapid and efficient enzymatic degradation of plant biomass into fermentable sugars is a major challenge for the sustainable production of biochemicals and biofuels. Enzymes that are more thermostable (up to 70°C) use shorter reaction times for the complete saccharification of plant polysaccharides compared to hydrolytic enzymes of mesophilic fungi such as Trichoderma and Aspergillus species. The genus Myceliophthora contains four thermophilic fungi producing industrially relevant thermostable enzymes. Within this genus, isolates belonging to M. heterothallica were recently separated from the well-described species M. thermophila. We evaluate here the potential of M. heterothallica isolates to produce efficient enzyme mixtures for biomass degradation. Compared to the other thermophilic Myceliophthora species, isolates belonging to M. heterothallica and M. thermophila grew faster on pretreated spruce, wheat straw, and giant reed. According to their protein profiles and in vitro assays after growth on wheat straw, (hemi-)cellulolytic activities differed strongly between M. thermophila and M. heterothallica isolates. Compared to M. thermophila, M. heterothallica isolates were better in releasing sugars from mildly pretreated wheat straw (with 5% HCl) with a high content of xylan. The high levels of residual xylobiose revealed that enzyme mixtures of Myceliophthora species lack sufficient β-xylosidase activity. Sexual crossing of two M. heterothallica showed that progenies had a large genetic and physiological diversity. In the future, this will allow further improvement of the plant biomass-degrading enzyme mixtures of M. heterothallica.

  17. Electricity production and microbial characterization of thermophilic microbial fuel cells.

    Science.gov (United States)

    Dai, Kun; Wen, Jun-Li; Zhang, Fang; Ma, Xi-Wen; Cui, Xiang-Yu; Zhang, Qi; Zhao, Ting-Jia; Zeng, Raymond J

    2017-11-01

    Thermophilic microbial fuel cell (TMFC) offers many benefits, but the investigations on the diversity of exoelectrogenic bacteria are scarce. In this study, a two-chamber TMFC was constructed using ethanol as an electron donor, and the microbial dynamics were analyzed by high-throughput sequencing and 16S rRNA clone-library sequencing. The open-circuit potential of TMFC was approximately 650mV, while the maximum voltage was around 550mV. The maximum power density was 437mW/m 2 , and the columbic efficiency in this work was 20.5±6.0%. The Firmicutes bacteria, related to the uncultured bacterium clone A55_D21_H_B_C01 with a similarity of 99%, accounted for 90.9% of all bacteria in the TMFC biofilm. This unknown bacterium has the potential to become a new thermophilic exoelectrogenic bacterium that is yet to be cultured. The development of TMFC-involved biotechnologies will be beneficial for the production of valuable chemicals and generation of energy in the future. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Global transport of thermophilic bacteria in atmospheric dust.

    Science.gov (United States)

    Perfumo, Amedea; Marchant, Roger

    2010-04-01

    Aerosols from dust storms generated in the Sahara-Sahel desert area of Africa are transported north over Europe and periodically result in dry dust precipitation in the Mediterranean region. Samples of dust collected in Turkey and Greece following two distinct desert storm events contained viable thermophilic organisms of the genus Geobacillus, namely G. thermoglucosidasius and G. thermodenitrificans, and the recently reclassified Aeribacillus pallidus (formerly Geobacillus pallidus). We present here evidence that African dust storms create an atmospheric bridge between distant geographical regions and that they are also probably the source of thermophilic geobacilli later deposited over northern Europe by rainfall or dust plumes themselves. The same organisms (99% similarity in the 16S rDNA sequence) were found in dust collected in the Mediterranean region and inhabiting cool soils in Northern Ireland. This study also contributes new insights to the taxonomic identification of Geobacillus sp. Attempts to identify these organisms using 16S rRNA gene sequences have revealed that they contain multiple and diverse copies of the ribosomal RNA operon (up to 10 copies with nine different sequences), which dictates care in interpreting data about the systematics of this genus. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

  19. Hydrolytic bacteria in mesophilic and thermophilic degradation of plant biomass

    Energy Technology Data Exchange (ETDEWEB)

    Zverlov, Vladimir V.; Hiegl, Wolfgang; Koeck, Daniela E.; Koellmeier, Tanja; Schwarz, Wolfgang H. [Department of Microbiology, Technische Universitaet Muenchen, Freising-Weihenstephan (Germany); Kellermann, Josef [Max Planck Institute for Biochemistry, Am Klopferspitz, Martinsried (Germany)

    2010-12-15

    Adding plant biomass to a biogas reactor, hydrolysis is the first reaction step in the chain of biological events towards methane production. Maize silage was used to enrich efficient hydrolytic bacterial consortia from natural environments under conditions imitating those in a biogas plant. At 55-60 C a more efficient hydrolyzing culture could be isolated than at 37 C. The composition of the optimal thermophilic bacterial consortium was revealed by sequencing clones from a 16S rRNA gene library. A modified PCR-RFLP pre-screening method was used to group the clones. Pure anaerobic cultures were isolated. 70% of the isolates were related to Clostridium thermocellum. A new culture-independent method for identification of cellulolytic enzymes was developed using the isolation of cellulose-binding proteins. MALDI-TOF/TOF analysis and end-sequencing of peptides from prominent protein bands revealed cellulases from the cellulosome of C. thermocellum and from a major cellulase of Clostridium stercorarium. A combined culture of C. thermocellum and C. stercorarium was shown to excellently degrade maize silage. A spore preparation method suitable for inoculation of maize silage and optimal hydrolysis was developed for the thermophilic bacterial consortium. This method allows for concentration and long-term storage of the mixed culture for instance for inoculation of biogas fermenters. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Enzyme activity screening of thermophilic bacteria isolated from Dusun Tua Hot Spring, Malaysia

    Science.gov (United States)

    Msarah, Marwan; Ibrahim, Izyanti; Aqma, Wan Syaidatul

    2018-04-01

    Thermophilic bacteria have biotechnological importance due to the availability of unique enzymes which are stable in extreme circumstances. The aim of this study includes to isolate thermophilic bacteria from hot spring and screen for important enzyme activities. Water samples from the Dusun Tua Hot Spring were collected and the physiochemical characterisation of water was measured. Eight thermophilic bacteria were isolated and determined to have at least three strong enzyme activity including protease, lipase, amylase, cellulase, pectinase and xylanase. The results showed that HuluC2 displayed all the enzyme activities and can be further studied.

  1. A Genetic System for the Thermophilic Acetogenic Bacterium Thermoanaerobacter kivui.

    Science.gov (United States)

    Basen, Mirko; Geiger, Irina; Henke, Laura; Müller, Volker

    2018-02-01

    Thermoanaerobacter kivui is one of the very few thermophilic acetogenic microorganisms. It grows optimally at 66°C on sugars but also lithotrophically with H 2 + CO 2 or with CO, producing acetate as the major product. While a genome-derived model of acetogenesis has been developed, only a few physiological or biochemical experiments regarding the function of important enzymes in carbon and energy metabolism have been carried out. To address this issue, we developed a method for targeted markerless gene deletions and for integration of genes into the genome of T. kivui The strain naturally took up plasmid DNA in the exponential growth phase, with a transformation frequency of up to 3.9 × 10 -6 A nonreplicating plasmid and selection with 5-fluoroorotate was used to delete the gene encoding the orotate phosphoribosyltransferase ( pyrE ), resulting in a Δ pyrE uracil-auxotrophic strain, TKV002. Reintroduction of pyrE on a plasmid or insertion of pyrE into different loci within the genome restored growth without uracil. We subsequently studied fructose metabolism in T. kivui The gene fruK (TKV_c23150) encoding 1-phosphofructosekinase (1-PFK) was deleted, using pyrE as a selective marker via two single homologous recombination events. The resulting Δ fruK strain, TKV003, did not grow on fructose; however, growth on glucose (or on mannose) was unaffected. The combination of pyrE as a selective marker and the natural competence of the strain for DNA uptake will be the basis for future studies on CO 2 reduction and energy conservation and their regulation in this thermophilic acetogenic bacterium. IMPORTANCE Acetogenic bacteria are currently the focus of research toward biotechnological applications due to their potential for de novo synthesis of carbon compounds such as acetate, butyrate, or ethanol from H 2 + CO 2 or from synthesis gas. Based on available genome sequences and on biochemical experiments, acetogens differ in their energy metabolism. Thus, there is an

  2. Microbial community dynamics in thermophilic undefined milk starter cultures.

    Science.gov (United States)

    Parente, Eugenio; Guidone, Angela; Matera, Attilio; De Filippis, Francesca; Mauriello, Gianluigi; Ricciardi, Annamaria

    2016-01-18

    Model undefined thermophilic starter cultures were produced from raw milk of nine pasta-filata cheesemaking plants using a selective procedure based on pasteurization and incubation at high temperature with the objective of studying the microbial community dynamics and the variability in performances under repeated (7-13) reproduction cycles with backslopping. The traditional culture-dependent approach, based on random isolation and molecular characterization of isolates was coupled to the determination of pH and the evaluation of the ability to produce acid and fermentation metabolites. Moreover, a culture-independent approach based on amplicon-targeted next-generation sequencing was employed. The microbial diversity was evaluated by 16S rRNA gene sequencing (V1-V3 regions), while the microdiversity of Streptococcus thermophilus populations was explored by using novel approach based on sequencing of partial amplicons of the phosphoserine phosphatase gene (serB). In addition, the occurrence of bacteriophages was evaluated by qPCR and by multiplex PCR. Although it was relatively easy to select for a community dominated by thermophilic lactic acid bacteria (LAB) within a single reproduction cycle, final pH, LAB populations and acid production activity fluctuated over reproduction cycles. Both culture-dependent and -independent methods showed that the cultures were dominated by either S. thermophilus or Lactobacillus delbrueckii subsp. lactis or by both species. Nevertheless, subdominant mesophilic species, including lactococci and spoilage organisms, persisted at low levels. A limited number of serB sequence types (ST) were present in S. thermophilus populations. L. delbrueckii and Lactococcus lactis bacteriophages were below the detection limit of the method used and high titres of cos type S. thermophilus bacteriophages were detected in only two cases. In one case a high titre of bacteriophages was concurrent with a S. thermophilus biotype shift in the culture

  3. Bioleaching of metals from electronic scrap by moderately thermophilic acidophilic bacteria

    NARCIS (Netherlands)

    Ilyas, Sadia; Anwar, Munir A.; Niazi, Shahida B.; Ghauri, M. Afzal

    The present work was aimed at studying the bioleachability of metals from electronic scrap by the selected moderately thermophilic strains of acidophilic chemolithotrophic and acidophilic heterotrophic bacteria. These included Sulfobacillus thermosulfidooxidans and an unidentified acidophilic

  4. Microbial community changes in methanogenic granules during the transition from mesophilic to thermophilic conditions

    DEFF Research Database (Denmark)

    Zhu, Xinyu; Kougias, Panagiotis; Treu, Laura

    2017-01-01

    Upflow anaerobic sludge blanket (UASB) reactor is one of the most applied technologies for various high-strength wastewater treatments. The present study analysed the microbial community changes in UASB granules during the transition from mesophilic to thermophilic conditions. Dynamicity...

  5. Hydrogen production by hyperthermophilic and extremely thermophilic bacteria and archaea: mechanisms for reductant disposal

    NARCIS (Netherlands)

    Verhaart, M.R.A.; Bielen, A.A.M.; Oost, van der J.; Stams, A.J.M.; Kengen, S.W.M.

    2010-01-01

    Hydrogen produced from biomass by bacteria and archaea is an attractive renewable energy source. However, to make its application more feasible, microorganisms are needed with high hydrogen productivities. For several reasons, hyperthermophilic and extremely thermophilic bacteria and archaea are

  6. Carbohydrate utilization patterns for the extremely thermophilic bacterium Caldicellulosiruptor saccharolyticus reveal broad growth substrate preferences

    NARCIS (Netherlands)

    Vanfossen, A.L.; Verhaart, M.R.A.; Kengen, S.W.M.; Kelly, R.M.

    2009-01-01

    Co-utilization of hexoses and pentoses derived from lignocellulose is an attractive trait in microorganisms considered for consolidated biomass processing to biofuels. This issue was examined for the H2-producing, extremely thermophilic bacterium Caldicellulosiruptor saccharolyticus growing on

  7. In vitro production of thymine dimer by ultroviolet irradiation of DNA from mesophilic and thermophilic bacteria

    International Nuclear Information System (INIS)

    Yein, F.S.; Stenesh, J.

    1989-01-01

    Thymine dimer was produced in vitro by ultraviolet irradiation of DNA, isolated from the mesophile Bacillus licheniformis and the thermophile B. stearothermophilus. Irradiation was performed at three different temperaturs (35, 45 and 55 C) and the thymine dimer was isolated and determined. An HPLC procedure was developed that permitted temperature was greater for the thermophile than for the mesophile. Formation of thymine dimer increased with temperature for both organisms but more so for the thermophile; over the temperature range of 35-55 C, the average increase in thymine dimer production for the themrophile was about 4-times that for the mesophile. The melting out temperature, as a function of increasing irradiation temperature, was essentially unchanged for the mesophilic DNA, but decreased progressively for the thermophilic DNA. These results are discussed in terms of the macromolecular theory of to the macromolecular theory of the thermophily. (author). 31 refs.; 4 figs.; 3 tabs

  8. Exceptional thermal stability and organic solvent tolerance of an esterase expressed from a thermophilic host

    DEFF Research Database (Denmark)

    Mei, Yuxia; Peng, Nan; Zhao, Shumiao

    2012-01-01

    , giving SisEstA. Upon Escherichia coli expression, only the thioredoxin-tagged EstA recombinant protein was soluble. The fusion protein was then purified, and removing the protein tag yielded EcSisEstA. Both forms of the thermophilic EstA enzyme were characterized. We found that SisEstA formed dimer...... that of EcSisEstA at 90°C. This indicated that thermophilic enzymes yielded from homologous expression should be better biocatalysts than those obtained from mesophilic expression.......A protein expression system recently developed for the thermophilic crenarchaeon Sulfolobus islandicus was employed to produce recombinant protein for EstA, a thermophilic esterase encoded in the same organism. Large amounts of protein were readily obtained by an affinity protein purification...

  9. Pyrophosphate as a central energy carrier in the hydrogen-producing extremely thermophilic Caldicellulosiruptor saccharolyticus

    NARCIS (Netherlands)

    Bielen, A.A.M.; Willquist, K.; Engman, J.; Oost, van der J.; Niel, van E.W.J.; Kengen, S.W.M.

    2010-01-01

    The role of inorganic pyrophosphate (PPi) as an energy carrier in the central metabolism of the extremely thermophilic bacterium Caldicellulosiruptor saccharolyticus was investigated. In agreement with its annotated genome sequence, cell extracts were shown to exhibit PPi-dependent

  10. Hydrogen production from carrot pulp by the extreme thermophiles Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana

    NARCIS (Netherlands)

    Vrije, de G.J.; Budde, M.A.W.; Lips, S.J.J.; Bakker, R.R.; Mars, A.E.; Claassen, P.A.M.

    2010-01-01

    Hydrogen was produced from carrot pulp hydrolysate, untreated carrot pulp and (mixtures of) glucose and fructose by the extreme thermophiles Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana in pH-controlled bioreactors. Carrot pulp hydrolysate was obtained after enzymatic hydrolysis

  11. Substrate and product inhibition of hydrogen production by the extreme thermophile, Caldicellulosiruptor saccharolyticus

    NARCIS (Netherlands)

    Niel, van E.W.J.; Claassen, P.A.M.; Stams, A.J.M.

    2003-01-01

    Substrate and product inhibition of hydrogen production during sucrose fermentation by the extremely thermophilic bacterium Caldicellulosiruptor saccharolyticus was studied. The inhibition kinetics were analyzed with a noncompetitive, nonlinear inhibition model. Hydrogen was the most severe

  12. Performance of thermophilic anaerobic digesters using inoculum mixes with enhanced methanogenic diversity

    KAUST Repository

    Ghanimeh, Sophia; El-Fadel, Mutasem; Saikaly, Pascal

    2017-01-01

    Reportedly, various mixes of seeds were quasi-randomly selected to startup anaerobic digesters. In contrast, this study examines the impact of inoculating thermophilic anaerobic digesters with a designed mix of non-acclimated seeds based

  13. Up-Streaming Process for Glucose Oxidase by Thermophilic Penicillium sp. in Shake Flask

    OpenAIRE

    Muhammad Mohsin JAVED; Aroosh SHABIR; Sana ZAHOOR; Ikram UL-HAQ

    2012-01-01

    The present study is concerned with the production of glucose oxidase (GOD) from thermophilic Penicillium sp. in 250 mL shake flask. Fourteen different strains of thermophilic Penicillium sp. were isolated from the soil and were screened for glucose oxidase production. IIBP-13 strain gave maximum extra-cellular glucose oxidase production as compared to other isolates. Effect of submerged fermentation in shaking and static conditions, different carbon sources and incubation period on the produ...

  14. Molecular diversity of thermophilic bacteria isolated from Pasinler hot spring (Erzurum, Turkey)

    OpenAIRE

    ADIGÜZEL, Ahmet; İNAN, Kadriye; ŞAHİN, Fikrettin; ARASOĞLU, Tulin; GÜLLÜCE, Medine

    2011-01-01

    The present study was conducted to determine the phenotypic and genotypic characterization of thermophilic bacteria isolated from Pasinler hot spring, Erzurum, Turkey. Fatty acid profiles, BOX PCR fingerprints, and 16S rDNA sequence data were used for the phenotypic and genotypic characterization of thermophilic bacteria. Totally 9 different bacterial strains were selected based on morphological, physiological, and biochemical tests. These strains were characterized by molecular tests includi...

  15. Kinetics of Butyrate, Acetate, and Hydrogen Metabolism in a Thermophilic, Anaerobic, Butyrate-Degrading Triculture

    OpenAIRE

    Ahring, Birgitte K.; Westermann, Peter

    1987-01-01

    Kinetics of butyrate, acetate, and hydrogen metabolism were determined with butyrate-limited, chemostat-grown tricultures of a thermophilic butyrate-utilizing bacterium together with Methanobacterium thermoautotrophicum and the TAM organism, a thermophilic acetate-utilizing methanogenic rod. Kinetic parameters were determined from progress curves fitted to the integrated form of the Michaelis-Menten equation. The apparent half-saturation constants, Km, for butyrate, acetate, and dissolved hyd...

  16. Desulfovibrio oceani subsp. oceani sp. nov., subsp. nov and Desulfovibrio oceani subsp. galateae subsp. nov., novel sulfate-reducing bacteria isolated from the oxygen minimum zone off the coast of Peru

    DEFF Research Database (Denmark)

    Finster, Kai; Kjeldsen, Kasper Urup

    2010-01-01

    Two deltaproteobacterial sulfate reducers, designated strain I.8.1T and I.9.1T, were isolated from the oxygen minimum zone water column off the coast of Peru at 400 and 500 m water depth. The strains were Gram-negative, vibrio-shaped and motile. Both strains were psychrotolerant, grew optimally...... growth as electron acceptors. Both strains were catalase-positive and highly oxygen-tolerant, surviving 24 days of exposure to atmospheric concentrations. MK6 was the only respiratory quinone. The most prominent cellular fatty acid was iso-17:1-ω9c (18%) for strain I.8.1T and iso-17:0-ω9c (14...

  17. Pathway engineering to improve ethanol production by thermophilic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Lynd, L.R.

    1998-12-31

    Continuation of a research project jointly funded by the NSF and DOE is proposed. The primary project goal is to develop and characterize strains of C. thermocellum and C. thermosaccharolyticum having ethanol selectivity similar to more convenient ethanol-producing organisms. An additional goal is to document the maximum concentration of ethanol that can be produced by thermophiles. These goals build on results from the previous project, including development of most of the genetic tools required for pathway engineering in the target organisms. As well, we demonstrated that the tolerance of C. thermosaccharolyticum to added ethanol is sufficiently high to allow practical utilization should similar tolerance to produced ethanol be demonstrated, and that inhibition by neutralizing agents may explain the limited concentrations of ethanol produced in studies to date. Task 1 involves optimization of electrotransformation, using either modified conditions or alternative plasmids to improve upon the low but reproducible transformation, frequencies we have obtained thus far.

  18. Hybrid biogas upgrading in a two-stage thermophilic reactor

    DEFF Research Database (Denmark)

    Corbellini, Viola; Kougias, Panagiotis; Treu, Laura

    2018-01-01

    The aim of this study is to propose a hybrid biogas upgrading configuration composed of two-stage thermophilic reactors. Hydrogen is directly injected in the first stage reactor. The output gas from the first reactor (in-situ biogas upgrade) is subsequently transferred to a second upflow reactor...... (ex-situ upgrade), in which enriched hydrogenotrophic culture is responsible for the hydrogenation of carbon dioxide to methane. The overall objective of the work was to perform an initial methane enrichment in the in-situ reactor, avoiding deterioration of the process due to elevated pH levels......, and subsequently, to complete the biogas upgrading process in the ex-situ chamber. The methane content in the first stage reactor reached on average 87% and the corresponding value in the second stage was 91%, with a maximum of 95%. A remarkable accumulation of volatile fatty acids was observed in the first...

  19. Bioleaching of pollymetallic sulphide concentrate using thermophilic bacteria

    Directory of Open Access Journals (Sweden)

    Vuković Milovan

    2014-01-01

    Full Text Available An extreme thermophilic, iron-sulphur oxidising bacterial culture was isolated and adapted to tolerate high metal and solids concentrations at 70°C. Following isolation and adaptation, the culture was used in a batch bioleach test employing a 5-l glass standard magnetic agitated and aerated reactor, for the bioleaching of a copper-lead-zinc collective concentrate. The culture exhibited stable leach performance over the period of leach operation and overall copper and zinc extractions higher than 97%. Lead sulphide is transformed into lead sulphate remaining in the bioleach residue due to the low solubility in sulphate media. Brine leaching of bioleach residue yields 95% lead extraction. [Projekat Ministarstva nauke Republike Srbije, br. 34023

  20. Synthetic polyester-hydrolyzing enzymes from thermophilic actinomycetes.

    Science.gov (United States)

    Wei, Ren; Oeser, Thorsten; Zimmermann, Wolfgang

    2014-01-01

    Thermophilic actinomycetes produce enzymes capable of hydrolyzing synthetic polyesters such as polyethylene terephthalate (PET). In addition to carboxylesterases, which have hydrolytic activity predominantly against PET oligomers, esterases related to cutinases also hydrolyze synthetic polymers. The production of these enzymes by actinomycetes as well as their recombinant expression in heterologous hosts is described and their catalytic activity against polyester substrates is compared. Assays to analyze the enzymatic hydrolysis of synthetic polyesters are evaluated, and a kinetic model describing the enzymatic heterogeneous hydrolysis process is discussed. Structure-function and structure-stability relationships of actinomycete polyester hydrolases are compared based on molecular dynamics simulations and recently solved protein structures. In addition, recent progress in enhancing their activity and thermal stability by random or site-directed mutagenesis is presented. © 2014 Elsevier Inc. All rights reserved.

  1. Biological hydrogen production by moderately thermophilic anaerobic bacteria

    International Nuclear Information System (INIS)

    HP Goorissen; AJM Stams

    2006-01-01

    This study focuses on the biological production of hydrogen at moderate temperatures (65-75 C) by anaerobic bacteria. A survey was made to select the best (moderate) thermophiles for hydrogen production from cellulolytic biomass. From this survey we selected Caldicellulosiruptor saccharolyticus (a gram-positive bacterium) and Thermotoga elfii (a gram-negative bacterium) as potential candidates for biological hydrogen production on mixtures of C 5 -C 6 sugars. Xylose and glucose were used as model substrates to describe growth and hydrogen production from hydrolyzed biomass. Mixed substrate utilization in batch cultures revealed differences in the sequence of substrate consumption and in catabolites repression of the two microorganisms. The regulatory mechanisms of catabolites repression in these microorganisms are not known yet. (authors)

  2. Characterisation of community structure of bacteria in parallel mesophilic and thermophilic pilot scale anaerobe sludge digesters.

    Science.gov (United States)

    Tauber, T; Berta, Brigitta; Székely, Anna J; Gyarmati, I; Kékesi, Katalin; Márialigeti, K; Tóth, Erika M

    2007-03-01

    The aim of the present work was to compare the microbial communities of a mesophilic and a thermophilic pilot scale anaerobe sludge digester. For studying the communities cultivation independent chemotaxonomical methods (RQ and PLFA analyses) and T-RFLP were applied. Microbial communities of the mesophilic and thermophilic pilot digesters showed considerable differences, both concerning the species present, and their abundance. A Methanosarcina sp. dominated the thermophilic, while a Methanosaeta sp. the mesophilic digester among Archaea. Species diversity of Bacteria was reduced in the thermophilic digester. Based on the quinone patterns in both digesters the dominance of sulphate reducing respiratory bacteria could be detected. The PLFA profiles of the digester communities were similar though in minor components characteristic differences were shown. Level of branched chain fatty acids is slightly lower in the thermophilic digester that reports less Gram positive bacteria. The relative ratio of fatty acids characteristic to Enterobacteriaceae, Bacteroidetes and Clostridia shows differences between the two digesters: their importance generally decreased under thermophilic conditions. The sulphate reducer marker (15:1 and 17:1) fatty acids are present in low quantity in both digesters.

  3. Diversity of Cultured Thermophilic Anaerobes in Hot Springs of Yunnan Province, China

    Science.gov (United States)

    Lin, L.; Lu, Y.; Dong, X.; Liu, X.; Wei, Y.; Ji, X.; Zhang, C.

    2010-12-01

    Thermophilic anaerobes including Archaea and Bacteria refer to those growing optimally at temperatures above 50°C and do not use oxygen as the terminal electron acceptor for growth. Study on thermophilic anaerobes will help to understand how life thrives under extreme conditions. Meanwhile thermophilic anaerobes are of importance in potential application and development of thermophilic biotechnology. We have surveyed culturable thermophilic anaerobes in hot springs (pH6.5-7.5; 70 - 94°C) in Rehai of Tengchong, Bangnazhang of Longlin, Eryuan of Dali,Yunnan, China. 50 strains in total were cultured from the hot springs water using Hungate anaerobic technique, and 30 strains were selected based on phenotypic diversity for analysis of 16S rDNA sequences. Phylogenetic analysis showed that 28 strains belonged to the members of five genera: Caldanaerobacter, Calaramator, Thermoanaerobacter, Dictyoglomus and Fervidobacterium, which formed five branches on the phylogenetic tree. Besides, 2 strains of methanogenic archaea were obtained. The majority of the isolates were the known species, however, seven strains were identified as novel species affiliated to the five genera based on the lower 16S rDNA sequence similarities (less than 93 - 97%) with the described species. This work would provide the future study on their diversity, distribution among different regions and the potential application of thermophilic enzyme. Supported by State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences(SKLMR-080605)and the Foundation of State Natural Science (30660009, 30960022, 31081220175).

  4. Comparative economic assessment of ethanol production under mesophilic and thermophilic conditions

    International Nuclear Information System (INIS)

    Mistry, P.B.

    1991-01-01

    Key technical factors affecting the economics of bioethanol production are critically analyzed with special reference to the relative merits of thermophilic and mesophilic fermentation. A number of novel process schemes to take advantage of thermophilic operation are discussed. Analysis of the capital and operating costs for a range of flowsheets then provides a basis for critical study. Estimates for thermophilic production are compared with those for a sugar cane based mesophilic process (using S. cerevisiae). For the thermophilic fermentation, the basic kinetic and yield constants are based on projected values for a strain of B. stearothermophilus. Compared to mesophilic operation, thermophilic operation results in reduced capital, operating and feed costs. The feed cost still accounts for a large proportion (75%) of the total production cost. However, on a feed-cost-free basis, a reduction in production cost of up to 32% could be realized by changing to thermophilic operation from existing yeast-based processes, after minor process modifications. 20 refs., 10 figs., 8 tabs

  5. Avoiding dangerous missense: thermophiles display especially low mutation rates.

    Directory of Open Access Journals (Sweden)

    John W Drake

    2009-06-01

    Full Text Available Rates of spontaneous mutation have been estimated under optimal growth conditions for a variety of DNA-based microbes, including viruses, bacteria, and eukaryotes. When expressed as genomic mutation rates, most of the values were in the vicinity of 0.003-0.004 with a range of less than two-fold. Because the genome sizes varied by roughly 10(4-fold, the mutation rates per average base pair varied inversely by a similar factor. Even though the commonality of the observed genomic rates remains unexplained, it implies that mutation rates in unstressed microbes reach values that can be finely tuned by evolution. An insight originating in the 1920s and maturing in the 1960s proposed that the genomic mutation rate would reflect a balance between the deleterious effect of the average mutation and the cost of further reducing the mutation rate. If this view is correct, then increasing the deleterious impact of the average mutation should be countered by reducing the genomic mutation rate. It is a common observation that many neutral or nearly neutral mutations become strongly deleterious at higher temperatures, in which case they are called temperature-sensitive mutations. Recently, the kinds and rates of spontaneous mutations were described for two microbial thermophiles, a bacterium and an archaeon. Using an updated method to extrapolate from mutation-reporter genes to whole genomes reveals that the rate of base substitutions is substantially lower in these two thermophiles than in mesophiles. This result provides the first experimental support for the concept of an evolved balance between the total genomic impact of mutations and the cost of further reducing the basal mutation rate.

  6. Performance and microbial community analysis of two-stage process with extreme thermophilic hydrogen and thermophilic methane production from hydrolysate in UASB reactors

    DEFF Research Database (Denmark)

    Kongjan, Prawit; O-Thong, Sompong; Angelidaki, Irini

    2011-01-01

    The two-stage process for extreme thermophilic hydrogen and thermophilic methane production from wheat straw hydrolysate was investigated in up-flow anaerobic sludge bed (UASB) reactors. Specific hydrogen and methane yields of 89ml-H2/g-VS (190ml-H2/g-sugars) and 307ml-CH4/g-VS, respectively were...... energy of 13.4kJ/g-VS. Dominant hydrogen-producing bacteria in the H2-UASB reactor were Thermoanaerobacter wiegelii, Caldanaerobacter subteraneus, and Caloramator fervidus. Meanwhile, the CH4-UASB reactor was dominated with methanogens of Methanosarcina mazei and Methanothermobacter defluvii. The results...

  7. Optimization of extracellular thermophilic highly alkaline lipase from thermophilic bacillus sp isolated from hotspring of Arunachal Pradesh, India

    Science.gov (United States)

    Bora, Limpon; Bora, Minakshi

    2012-01-01

    Studies on lipase production were carried out with a bacterial strain (Bacillus sp LBN 2) isolated from soil sample of hotspring of Arunachal Pradesh, India. The cells were cultivated in a mineral medium with maximum production at 1% groundnut oil. The optimum temperature and initial medium pH for lipase production by the organism were 500C and 9.0 respectively. The molecular mass was found to be 33KDa by SDS PAGE. The optimal pH and temperature for activity were 10 and 600C respectively. The enzyme was found to be stable in the pH range of 8–11 with 90% retention of activity at pH 11. The enzyme retained 90% activity at 600C and 70% of activity at 700C for 1h. The lipase was found to be stable in acetone followed by ethanol. The present findings suggested the enzyme to be thermophilic alkaline lipase. PMID:24031801

  8. Extremely Thermophilic Microorganisms as Metabolic Engineering Platforms for Production of Fuels and Industrial Chemicals

    Directory of Open Access Journals (Sweden)

    Benjamin M Zeldes

    2015-11-01

    Full Text Available Enzymes from extremely thermophilic microorganisms have been of technological interest for some time because of their ability to catalyze reactions of industrial significance at elevated temperatures. Thermophilic enzymes are now routinely produced in recombinant mesophilic hosts for use as discrete biocatalysts. Genome and metagenome sequence data for extreme thermophiles provide useful information for putative biocatalysts for a wide range of biotransformations, albeit involving at most a few enzymatic steps. However, in the past several years, unprecedented progress has been made in establishing molecular genetics tools for extreme thermophiles to the point that the use of these microorganisms as metabolic engineering platforms has become possible. While in its early days, complex metabolic pathways have been altered or engineered into recombinant extreme thermophiles, such that the production of fuels and chemicals at elevated temperatures has become possible. Not only does this expand the thermal range for industrial biotechnology, it also potentially provides biodiverse options for specific biotransformations unique to these microorganisms. The list of extreme thermophiles growing optimally between 70 and 100°C with genetic toolkits currently available includes archaea and bacteria, aerobes and anaerobes, coming from genera such as Caldicellulosiruptor, Sulfolobus, Thermotoga, Thermococcus and Pyrococcus. These organisms exhibit unusual and potentially useful native metabolic capabilities, including cellulose degradation, metal solubilization, and RuBisCO-free carbon fixation. Those looking to design a thermal bioprocess now have a host of potential candidates to choose from, each with its own advantages and challenges that will influence its appropriateness for specific applications. Here, the issues and opportunities for extremely thermophilic metabolic engineering platforms are considered with an eye towards potential technological

  9. Extremely thermophilic microorganisms as metabolic engineering platforms for production of fuels and industrial chemicals

    Science.gov (United States)

    Zeldes, Benjamin M.; Keller, Matthew W.; Loder, Andrew J.; Straub, Christopher T.; Adams, Michael W. W.; Kelly, Robert M.

    2015-01-01

    Enzymes from extremely thermophilic microorganisms have been of technological interest for some time because of their ability to catalyze reactions of industrial significance at elevated temperatures. Thermophilic enzymes are now routinely produced in recombinant mesophilic hosts for use as discrete biocatalysts. Genome and metagenome sequence data for extreme thermophiles provide useful information for putative biocatalysts for a wide range of biotransformations, albeit involving at most a few enzymatic steps. However, in the past several years, unprecedented progress has been made in establishing molecular genetics tools for extreme thermophiles to the point that the use of these microorganisms as metabolic engineering platforms has become possible. While in its early days, complex metabolic pathways have been altered or engineered into recombinant extreme thermophiles, such that the production of fuels and chemicals at elevated temperatures has become possible. Not only does this expand the thermal range for industrial biotechnology, it also potentially provides biodiverse options for specific biotransformations unique to these microorganisms. The list of extreme thermophiles growing optimally between 70 and 100°C with genetic toolkits currently available includes archaea and bacteria, aerobes and anaerobes, coming from genera such as Caldicellulosiruptor, Sulfolobus, Thermotoga, Thermococcus, and Pyrococcus. These organisms exhibit unusual and potentially useful native metabolic capabilities, including cellulose degradation, metal solubilization, and RuBisCO-free carbon fixation. Those looking to design a thermal bioprocess now have a host of potential candidates to choose from, each with its own advantages and challenges that will influence its appropriateness for specific applications. Here, the issues and opportunities for extremely thermophilic metabolic engineering platforms are considered with an eye toward potential technological advantages for high

  10. Mesophilic and thermophilic anaerobic digestion of biologically pretreated abattoir wastewaters in an upflow anaerobic filter

    International Nuclear Information System (INIS)

    Gannoun, H.; Bouallagui, H.; Okbi, A.; Sayadi, S.; Hamdi, M.

    2009-01-01

    The hydrolysis pretreatment of abattoir wastewaters (AW), rich in organic suspended solids (fats and protein) was studied in static and stirred batch reactors without aeration in the presence of natural microbial population acclimated in a storage tank of AW. Microbial analysis showed that the major populations which contribute to the pretreatment of AW belong to the genera Bacillus. Contrary to the static pretreatment, the stirred conditions favoured the hydrolysis and solubilization of 80% of suspended matter into soluble pollution. The pretreated AW, in continuous stirred tank reactor (CSTR) at a hydraulic retention time (HRT) of 2 days, was fed to an upflow anaerobic filter (UAF) at an HRT of 2 days. The performance of anaerobic digestion of biologically pretreated AW was examined under mesophilic (37 deg. C) and thermophilic (55 deg. C) conditions. The shifting from a mesophilic to a thermophilic environment in the UAF was carried out with a short start-up of thermophilic condition. The UAF ran at organic loading rates (OLRs) ranging from 0.9 to 6 g COD/L d in mesophilic conditions and at OLRs from 0.9 to 9 g COD/L d in thermophilic conditions. COD removal efficiencies of 80-90% were achieved for OLRs up to 4.5 g COD/L d in mesophilic conditions, while the highest OLRs i.e. 9 g COD/L d led to efficiencies of 70-72% in thermophilic conditions. The biogas yield in thermophilic conditions was about 0.32-0.45 L biogas/g of COD removed for OLRs up to 4.5 g COD/L d. For similar OLR, the UAF in mesophilic conditions showed lower percentage of methanization. Mesophilic anaerobic digestion has been shown to destroy pathogens partially, whereas the thermophilic process was more efficient in the removal of indicator microorganisms and pathogenic bacteria at different organic loading rates.

  11. Estimation of extracellular lipase enzyme produced by thermophilic bacillus sp. isolated from arid and semi-arid region of Rajasthan, India

    OpenAIRE

    Deeksha Gaur; Pankaj Kumar Jain; Yamini Singh Sisodia; Vivek Bajpai

    2012-01-01

    Thermophilic organisms can be defined as microorganisms which are adapted to live at high temperatures. The enzymes produce by thermophilic bacteria are capable of catalyzing biochemical reactions at high temperatures. Thermophilic bacteria are able to produce thermostable lipase enzymes capable of degradation of lipid at temperatures higher than those of mesophilic bacteria. Therefore, the isolation of thermophilic bacteria from natural sources and their identification are quite useful in te...

  12. Biological hydrogen production from biomass by thermophilic bacteria

    International Nuclear Information System (INIS)

    Claassen, P.A.M.; Mars, A.E.; Budde, M.A.W.; Lai, M.; de Vrije, T.; van Niel, E.W.J.

    2006-01-01

    To meet the reduction of the emission of CO 2 imposed by the Kyoto protocol, hydrogen should be produced from renewable primary energy. Besides the indirect production of hydrogen by electrolysis using electricity from renewable resources, such as sunlight, wind and hydropower, hydrogen can be directly produced from biomass. At present, there are two strategies for the production of hydrogen from biomass: the thermochemical technology, such as gasification, and the biotechnological approach using micro-organisms. Biological hydrogen production delivers clean hydrogen with an environmental-friendly technology and is very suitable for the conversion of wet biomass in small-scale applications, thus having a high chance of becoming an economically feasible technology. Many micro-organisms are able to produce hydrogen from mono- and disaccharides, starch and (hemi)cellulose under anaerobic conditions. The anaerobic production of hydrogen is a common phenomenon, occurring during the process of anaerobic digestion. Here, hydrogen producing micro-organisms are in syn-trophy with methanogenic bacteria which consume the hydrogen as soon as it is produced. In this way, hydrogen production remains obscure and methane is the end-product. By uncoupling hydrogen production from methane production, hydrogen becomes available for recovery and exploitation. This study describes the use of extreme thermophilic bacteria, selected because of a higher hydrogen production efficiency as compared to mesophilic bacteria, for the production of hydrogen from renewable resources. As feedstock energy crops like Miscanthus and Sorghum bicolor and waste streams like domestic organic waste, paper sludge and potato steam peels were used. The feedstock was pretreated and/or enzymatically hydrolyzed prior to fermentation to make a fermentable substrate. Hydrogen production by Caldicellulosiruptor saccharolyticus, Thermotoga elfii and T. neapolitana on all substrates was observed. Nutrient

  13. Reduction of hexavalent chromium by the thermophilic methanogen Methanothermobacter thermautotrophicus

    Science.gov (United States)

    Singh, Rajesh; Dong, Hailiang; Liu, Deng; Zhao, Linduo; Marts, Amy R.; Farquhar, Erik; Tierney, David L.; Almquist, Catherine B.; Briggs, Brandon R.

    2015-01-01

    Despite significant progress on iron reduction by thermophilic microorganisms, studies on their ability to reduce toxic metals are still limited, despite their common co-existence in high temperature environments (up to 70 °C). In this study, Methanothermobacter thermautotrophicus, an obligate thermophilic methanogen, was used to reduce hexavalent chromium. Experiments were conducted in a growth medium with H2/CO2 as substrate with various Cr6+ concentrations (0.2, 0.4, 1, 3, and 5 mM) in the form of potassium dichromate (K2Cr2O7). Time-course measurements of aqueous Cr6+ concentrations using 1,5-diphenylcarbazide colorimetric method showed complete reduction of the 0.2 and 0.4 mM Cr6+ solutions by this methanogen. However, much lower reduction extents of 43.6%, 13.0%, and 3.7% were observed at higher Cr6+ concentrations of 1, 3 and 5 mM, respectively. These lower extents of bioreduction suggest a toxic effect of aqueous Cr6+ to cells at this concentration range. At these higher Cr6+ concentrations, methanogenesis was inhibited and cell growth was impaired as evidenced by decreased total cellular protein production and live/dead cell ratio. Likewise, Cr6+ bioreduction rates decreased with increased initial concentrations of Cr6+ from 13.3 to 1.9 μM h-1. X-ray absorption near-edge structure (XANES) spectroscopy revealed a progressive reduction of soluble Cr6+ to insoluble Cr3+ precipitates, which was confirmed as amorphous chromium hydroxide by selected area electron diffraction pattern. However, a small fraction of reduced Cr occurred as aqueous Cr3+. Scanning and transmission electron microscope observations of M. thermautotrophicus cells after Cr6+ exposure suggest both extra- and intracellular chromium reduction mechanisms. Results of this study demonstrate the ability of M. thermautotrophicus cells to reduce toxic Cr6+ to less toxic Cr3+ and its potential application in metal bioremediation, especially at high temperature subsurface radioactive waste disposal

  14. Rapid startup of thermophilic anaerobic digester to remove tetracycline and sulfonamides resistance genes from sewage sludge.

    Science.gov (United States)

    Xu, Rui; Yang, Zhao-Hui; Wang, Qing-Peng; Bai, Yang; Liu, Jian-Bo; Zheng, Yue; Zhang, Yan-Ru; Xiong, Wei-Ping; Ahmad, Kito; Fan, Chang-Zheng

    2018-01-15

    Spread of antibiotic resistance genes (ARGs) originating from sewage sludge is highlighted as an eminent health threat. This study established a thermophilic anaerobic digester using one-step startup strategy to quickly remove tetracycline and sulfonamides resistance genes from sewage sludge. At least 20days were saved in the startup period from mesophilic to thermophilic condition. Based on the results of 16S rDNA amplicons sequencing and predicted metagenomic method, the successful startup largely relied on the fast colonization of core thermophilic microbial population (e.g. Firmicutes, Proteobacteria, Actinobacteria). Microbial metabolic gene pathways for substrate degradation and methane production was also increased by one-step mode. In addition, real-time quantitative PCR approach revealed that most targeted tetracycline and sulfonamides resistance genes ARGs (sulI, tetA, tetO, tetX) were substantially removed during thermophilic digestion (removal efficiency>80%). Network analysis showed that the elimination of ARGs was attributed to the decline of their horizontal (intI1 item) and vertical (potential hosts) transfer-related elements under high-temperature. This research demonstrated that rapid startup thermophilic anaerobic digestion of wastewater solids would be a suitable technology for reducing quantities of various ARGs. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Community dynamics and glycoside hydrolase activities of thermophilic bacterial consortia adapted to switchgrass

    Energy Technology Data Exchange (ETDEWEB)

    Gladden, J.M.; Allgaier, M.; Miller, C.S.; Hazen, T.C.; VanderGheynst, J.S.; Hugenholtz, P.; Simmons, B.A.; Singer, S.W.

    2011-05-01

    Industrial-scale biofuel production requires robust enzymatic cocktails to produce fermentable sugars from lignocellulosic biomass. Thermophilic bacterial consortia are a potential source of cellulases and hemicellulases adapted to harsher reaction conditions than commercial fungal enzymes. Compost-derived microbial consortia were adapted to switchgrass at 60 C to develop thermophilic biomass-degrading consortia for detailed studies. Microbial community analysis using small-subunit rRNA gene amplicon pyrosequencing and short-read metagenomic sequencing demonstrated that thermophilic adaptation to switchgrass resulted in low-diversity bacterial consortia with a high abundance of bacteria related to thermophilic paenibacilli, Rhodothermus marinus, and Thermus thermophilus. At lower abundance, thermophilic Chloroflexi and an uncultivated lineage of the Gemmatimonadetes phylum were observed. Supernatants isolated from these consortia had high levels of xylanase and endoglucanase activities. Compared to commercial enzyme preparations, the endoglucanase enzymes had a higher thermotolerance and were more stable in the presence of 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]), an ionic liquid used for biomass pretreatment. The supernatants were used to saccharify [C2mim][OAc]-pretreated switchgrass at elevated temperatures (up to 80 C), demonstrating that these consortia are an excellent source of enzymes for the development of enzymatic cocktails tailored to more extreme reaction conditions.

  16. Reduction of Fe(III) oxides by phylogenetically and physiologically diverse thermophilic methanogens.

    Science.gov (United States)

    Yamada, Chihaya; Kato, Souichiro; Kimura, Satoshi; Ishii, Masaharu; Igarashi, Yasuo

    2014-09-01

    Three thermophilic methanogens (Methanothermobacter thermautotrophicus, Methanosaeta thermophila, and Methanosarcina thermophila) were investigated for their ability to reduce poorly crystalline Fe(III) oxides (ferrihydrite) and the inhibitory effects of ferrihydrite on their methanogenesis. This study demonstrated that Fe(II) generation from ferrihydrite occurs in the cultures of the three thermophilic methanogens only when H2 was supplied as the source of reducing equivalents, even in the cultures of Mst. thermophila that do not grow on and produce CH4 from H2/CO2. While supplementation of ferrihydrite resulted in complete inhibition or suppression of methanogenesis by the thermophilic methanogens, ferrihydrite reduction by the methanogens at least partially alleviates the inhibitory effects. Microscopic and crystallographic analyses on the ferrihydrite-reducing Msr. thermophila cultures exhibited generation of magnetite on its cell surfaces through partial reduction of ferrihydrite. These findings suggest that at least certain thermophilic methanogens have the ability to extracellularly transfer electrons to insoluble Fe(III) compounds, affecting their methanogenic activities, which would in turn have significant impacts on materials and energy cycles in thermophilic anoxic environments. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  17. Dewaterability of thermophilically digested biosolids: effects of temperature and cellular polymeric substances

    International Nuclear Information System (INIS)

    Zhou, J.; Mavinic, D.S.; Kelly, H.G.; Ramey, W.D.

    2002-01-01

    Thermophilic processes digest sludge at high temperatures to produce Class A biosolids.Recent research work revealed that digestion temperature is the predominant factor affecting dewaterability of thermophilic biosolids. This paper presents findings of a laboratory study that investigated how various digestion temperatures affect dewaterability of digested biosolids, studied the phase partition of the substances affecting dewaterability in digested biosolids, and tested the role of cellular polymeric substances in affecting dewaterability.Secondary sludges were digested at 40-70 o C or 22 o C for up to 12 days. Centrate from thermophilically digested biosolids were treated with protease and boiling. This study found that, during the first few hours of digestion, higher temperatures resulted in more rapid and more significant deterioration in dewaterability than lower digestion temperatures. Continued digestion resulted in either improved (60 o C or 70 o C), or unchanged (40 o C or 50 o C), or gradually deteriorated dewaterability (22 o C). The substances affecting dewaterability were primarily located in the liquid phase of thermophilically digested biosolids. Boiling treatment did not result in significant changes in dewaterability. Protease treatment of the liquid phase of thermophilic biosolids improved dewaterability by 13-19%. Such an improvement confirmed the role of proteins in affecting dewaterability. (author)

  18. Comparing Residue Clusters from Thermophilic and Mesophilic Enzymes Reveals Adaptive Mechanisms.

    Directory of Open Access Journals (Sweden)

    Deanne W Sammond

    Full Text Available Understanding how proteins adapt to function at high temperatures is important for deciphering the energetics that dictate protein stability and folding. While multiple principles important for thermostability have been identified, we lack a unified understanding of how internal protein structural and chemical environment determine qualitative or quantitative impact of evolutionary mutations. In this work we compare equivalent clusters of spatially neighboring residues between paired thermophilic and mesophilic homologues to evaluate adaptations under the selective pressure of high temperature. We find the residue clusters in thermophilic enzymes generally display improved atomic packing compared to mesophilic enzymes, in agreement with previous research. Unlike residue clusters from mesophilic enzymes, however, thermophilic residue clusters do not have significant cavities. In addition, anchor residues found in many clusters are highly conserved with respect to atomic packing between both thermophilic and mesophilic enzymes. Thus the improvements in atomic packing observed in thermophilic homologues are not derived from these anchor residues but from neighboring positions, which may serve to expand optimized protein core regions.