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Sample records for denitrifying enrichment cultures

  1. Degradation of toluene and m-xylene and transformation of o-xylene by denitrifying enrichment cultures.

    Science.gov (United States)

    Evans, P J; Mang, D T; Young, L Y

    1991-01-01

    Seven different sources of inocula that included sediments, contaminated soils, groundwater, process effluent, and sludge were used to establish enrichment cultures of denitrifying bacteria on benzene, toluene, and xylenes in the absence of molecular oxygen. All of the enrichment cultures demonstrated complete depletion of toluene and partial depletion of o-xylene within 3 months of incubation. The depletion of o-xylene was correlated to and dependent on the metabolism of toluene. No losses of benzene, p-xylene, or m-xylene were observed in these initial enrichment cultures. However, m-xylene was degraded by a subculture that was incubated on m-xylene alone. Complete carbon, nitrogen, and electron balances were determined for the degradation of toluene and m-xylene. These balances showed that these compounds were mineralized with greater than 50% conversion to CO2 and significant assimilation into biomass. Additionally, the oxidation of these compounds was shown to be dependent on nitrate reduction and denitrification. These microbial degradative capabilities appear to be widespread, since the widely varied inoculum sources all yielded similar results. PMID:2014990

  2. Anaerobic oxidation of cholesterol by a denitrifying enrichment.

    Science.gov (United States)

    Barrandeguy, E; Tarlera, S

    2001-01-01

    Sterols (e.g. cholesterol) present in wool scouring effluent represent the most recalcitrant fraction in anaerobic treatment. This study was conducted to examine the feasibility of removal of this organic load through a denitrifying post-treatment stage. A stable cholesterol-denitrifying enrichment (CHOL-1) was obtained from sludge of a bench-scale upflow sludge bed (USB) denitrifying reactor integrated to a carbon and nitrogen removal system for sanitary landfill leachate. According to the amounts of cholesterol degraded and of nitrite and nitrogen gas formed, the capacity for complete cholesterol oxidation under anaerobic conditions by CHOL-1 can be assumed. Nitrite accumulation observed at a low C/N ratio outlines the importance of determining the optimal C/N ratio for adequate denitrifying reactor performance. The enrichment was partly identified with molecular analysis of cloned 16S rDNA sequences revealing the presence of two groups of bacteria belonging to the beta subclass of the Proteobacteria. According to analysis of sequences, it can be inferred that a yet uncultivated new bacterium is the one responsible for cholesterol oxidation. Results of this study suggest that sludge from a denitrifying reactor treating leachate is potentially useful in a combined anaerobic-anoxic system for degradation of cholesterol that remains after methanogenic treatment. PMID:11575077

  3. Enrichment of denitrifying methanotrophic bacteria for application after direct low-temperature anaerobic sewage treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kampman, Christel, E-mail: christel.kampman@wur.nl [Sub-department of Environmental Technology, Wageningen University, P.O. Box 17, 6700 AA, Wageningen (Netherlands); Hendrickx, Tim L.G. [Sub-department of Environmental Technology, Wageningen University, P.O. Box 17, 6700 AA, Wageningen (Netherlands); Luesken, Francisca A.; Alen, Theo A. van; Op den Camp, Huub J.M.; Jetten, Mike S.M. [Department of Microbiology, Institute for Water and Wetland Research, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen (Netherlands); Zeeman, Grietje; Buisman, Cees J.N.; Temmink, Hardy [Sub-department of Environmental Technology, Wageningen University, P.O. Box 17, 6700 AA, Wageningen (Netherlands)

    2012-08-15

    Highlights: Black-Right-Pointing-Pointer A new concept for low-temperature anaerobic sewage treatment is proposed. Black-Right-Pointing-Pointer In this concept, denitrification and methane oxidation are performed by Methylomirabilis oxyfera. Black-Right-Pointing-Pointer The bacteria were enriched from fresh water sediment using sequencing fed-batch reactors. Black-Right-Pointing-Pointer The volumetric consumption rate has to be increased by an order of magnitude for practical application. Black-Right-Pointing-Pointer Further research should focus on systems with improved biomass retention. - Abstract: Despite many advantages of anaerobic sewage treatment over conventional activated sludge treatment, it has not yet been applied in temperate zones. This is especially because effluent from low-temperature anaerobic treatment contains nitrogen and dissolved methane. The presence of nitrogen and methane offers the opportunity to develop a reactor in which methane is used as electron donor for denitrification. Such a reactor could be used in a new concept for low-temperature anaerobic sewage treatment, consisting of a UASB-digester system, a reactor for denitrification coupled to anaerobic methane oxidation, and a nitritation reactor. In the present study denitrifying methanotrophic bacteria similar to 'Candidatus Methylomirabilis oxyfera' were enriched. Maximum volumetric nitrite consumption rates were 33.5 mg NO{sub 2}{sup -}-N/L d (using synthetic medium) and 37.8 mg NO{sub 2}{sup -}-N/L d (using medium containing effluent from a sewage treatment plant), which are similar to the maximum rate reported so far. Though the goal was to increase the rates, in both reactors, after reaching these maximum rates, volumetric nitrite consumption rates decreased in time. Results indicate biomass washout may have significantly decelerated enrichment. Therefore, to obtain higher volumetric consumption rates, further research should focus on systems with complete biomass retention.

  4. Enrichment of denitrifying methanotrophic bacteria for application after direct low-temperature anaerobic sewage treatment

    International Nuclear Information System (INIS)

    Highlights: ? A new concept for low-temperature anaerobic sewage treatment is proposed. ? In this concept, denitrification and methane oxidation are performed by Methylomirabilis oxyfera. ? The bacteria were enriched from fresh water sediment using sequencing fed-batch reactors. ? The volumetric consumption rate has to be increased by an order of magnitude for practical application. ? Further research should focus on systems with improved biomass retention. - Abstract: Despite many advantages of anaerobic sewage treatment over conventional activated sludge treatment, it has not yet been applied in temperate zones. This is especially because effluent from low-temperature anaerobic treatment contains nitrogen and dissolved methane. The presence of nitrogen and methane offers the opportunity to develop a reactor in which methane is used as electron donor for denitrification. Such a reactor could be used in a new concept for low-temperature anaerobic sewage treatment, consisting of a UASB-digester system, a reactor for denitrification coupled to anaerobic methane oxidation, and a nitritation reactor. In the present study denitrifying methanotrophic bacteria similar to ‘Candidatus Methylomirabilis oxyfera’ were enriched. Maximum volumetric nitrite consumption rates were 33.5 mg NO2?-N/L d (using synthetic medium) and 37.8 mg NO2?-N/L d (using medium containing effluent from a sewage treatment plant), which are similar to the maximum rate reported so far. Though the goal was to increase the rates, in both reactors, after reaching these maximum rates, volumetric nitrite consumption rates decreased in time. Results indicate biomass washout may have significantly decelerated enrichment. Therefore, to obtain higher volumetric consumption rates, further research should focus on systems with complete biomass retention.

  5. Acute and chronic responses of denitrifying culture to diclofenac.

    Science.gov (United States)

    Ozdemir, Gamze; Aydin, Egemen; Topuz, Emel; Yangin-Gomec, Cigdem; Okutman Tas, Didem

    2015-01-01

    Acute and chronic effect as well as biodegradation potential at different sludge retention times (SRTs) of a priority pollutant, diclofenac on denitrification process was assessed. The continuous amendment of the culture for 6months with 1?g/L diclofenac resulted in 30% decrease in gas production. The average diclofenac removal observed in the diclofenac-acclimated culture was less than 15%. Batch tests showed that nitrate was removed in diclofenac free-control reactor at a higher rate compared to diclofenac amended reactor. Although, SRT did not have any progressive effect on diclofenac degradation, the system operated at low SRT was more sensitive to diclofenac and resulted in an increase in N2O emission. Wastewater treatment plants (WWTPs) operated at higher SRTs may tolerate and recover from the adverse effects of such micropollutants. The study can lead to other researchers to understand the fate and effect of other emerging pollutants in the anoxic unit of WWTPs. PMID:25460991

  6. Anaerobic Toluene Activation by Benzylsuccinate Synthase in a Highly Enriched Methanogenic Culture

    OpenAIRE

    Beller, Harry R.; Edwards, Elizabeth A

    2000-01-01

    Permeabilized cells of a highly enriched, toluene-mineralizing, methanogenic culture catalyzed the addition of toluene to fumarate to form benzylsuccinate under anaerobic conditions. The specific in vitro rate of benzylsuccinate formation was >85% of the specific in vivo rate of toluene consumption. This is the first report of benzylsuccinate synthase activity in a methanogenic culture; the activity has previously been reported to occur in denitrifying, sulfate-reducing, and anoxygenic photot...

  7. IDENTIFICATION AND ECOPHYSIOLOGY OF ACTIVE DENITRIFIERS IN ACTIVATED SLUDGE

    DEFF Research Database (Denmark)

    Hansen, Aviaja Anna; Le-Quy, Vang; Nielsen, Kåre Lehmann; Nielsen, Jeppe Lund

    2010-01-01

    Denitrification is of crucial importance for nitrogen removal in wastewater treatment. However, due to the polyphyletic taxonomy of denitrifiers, little is known about their community composition and ecophysiology and the available knowledge derives mainly from culture-dependent studies or enriched reactor studies. To obtain better identification of active denitrifying communities in full-scale wastewater treatment plants (WWTPs) we applied DNA-SIP with 13C-labelled substrates, and RT-PCR of exp...

  8. Functional characterization of heterotrophic denitrifying bacteria in activated sludge

    Scientific Electronic Library Online (English)

    Nishani, Ramdhani; Faizal, Bux.

    2007-04-01

    Full Text Available Wastewater treatment facilities are largely accountable for the detrimental enrichment of water bodies with nitrogenous compounds, resulting in eutrophication. Denitrification is of interest as a means of removing nitrates and nitrites from water supplies because they are also hazardous to human hea [...] lth. The integration of biological nutrient removal into conventional wastewater treatment processes has, however, failed to take into sufficient consideration the role of key microorganisms present, specifically denitrifying bacteria. The purpose of the study reported here was to group such heterotrophic denitrifying bacteria using a series of biochemical and molecular analyses, to achieve an improved understanding of their functions. The role of the denitrifying bacteria in reducing nitrate and nitrite was monitored using the colorimetric nitrate reduction test. The genetic diversity of the culture collection was investigated by the use of denaturing gradient gel electrophoresis (DGGE), which enabled the creation of a microbial population profile of eight predominant isolates. Batch experiments were conducted on these isolates, the results of which ultimately confirmed their classification according to their respective functions, namely, incomplete denitrifiers, true denitrifiers, sequential denitrifiers, and exclusive nitrite reducers.

  9. Cultural Enrichment through Community Action.

    Science.gov (United States)

    Wilson, O. J.

    This project was conceived as a technique for helping to eliminate a cultural void in the areas of art, music, and theatre in the service area of Western Kentucky University. To implement this concept, demonstrations were conducted in art, music, theatre, and in library and lecture resources in 16 counties over a four-year period. The attendance…

  10. Enrichment of high ammonia tolerant methanogenic culture

    DEFF Research Database (Denmark)

    Fotidis, Ioannis; Karakashev, Dimitar Borisov

    Ammonia is the major toxicant in full scale anaerobic digesters of animal wastes which are rich in proteins and/or urea, such as pig or poultry wastes. Ammonia inhibition decreases methane production rates, increases volatile fatty acids concentration and leads to economic losses for the biogas plants. The methods used today to counteract ammonia inhibition are slow and costexpensive. A new biological approach to avoid or counteract ammonia inhibition by using ammonia tolerant methanogens, could provide a sustainable solution for cost-effective digestion of abundant ammonia-rich wastes. The aim of the current study was to isolate and identify methanogenic cultures tolerant to high ammonia concentrations. A mixed methanogenic population was stepwise exposed to ammonia concentrations (1 to 9.26 g NH4+-N L-1) during an enrichment process with successive batch cultivations. The methanogenic population was derived from a full scale biogas reactor (Hashøj, Denmark), fed with 75% animal manure and 25% food industries organic waste. Basal anaerobic medium was used for the enrichment along with sodium acetate (1 g HAc L-1) as a carbon source. Fluorescence insitu hybridization (FISH) was used to determine microbial community composition. The outcome of the enrichment process was a mesophilic aceticlastic methanogenic enriched culture able to withstand high ammonia loads and utilize acetate and form methane stoichiometrically. FISH analysis showed that the methanogens of the enriched culture belonged exclusively to strict aceticlastic methanogens. Results obtained in this study, demonstrated for the first time that strictly aceticlastic methanogens, derived from an enriched culture, can efficiently produce methane under high ammonia levels.

  11. Mineralization of Trichloroethylene by Heterotrophic Enrichment Cultures

    OpenAIRE

    Fliermans, C. B.; Phelps, T J; Ringelberg, D.; Mikell, A. T.; White, D C

    1988-01-01

    Microbial consortia capable of aerobically degrading more than 99% of exogenous trichloroethylene (TCE) (50 mg/liter) were collected from TCE-contaminated subsurface sediments and grown in enrichment cultures. TCE at concentrations greater than 300 mg/liter was not degraded, nor was TCE used by the consortia as a sole energy source. Energy sources which permitted growth included tryptone-yeast extract, methanol, methane, and propane. The optimum temperature range for growth and subsequent TCE...

  12. Highly enriched Betaproteobacteria growing anaerobically with p-xylene and nitrate

    DEFF Research Database (Denmark)

    Rotaru, Amelia-Elena; Probian, Christina; Wilkes, Heinz; Harder, Jens

    2010-01-01

    The identity of the microorganisms capable of anaerobic p-xylene degradation under denitrifying conditions is hitherto unknown. Here, we report highly enriched cultures of freshwater denitrifying bacteria that grow anaerobically with p-xylene as the sole organic carbon source and electron donor. Long curved rods, with 95% 16S rRNA gene sequence identity to Denitratisoma oestradiolicum, dominated the enrichment cultures (>91% of all cells), as detected by phylotype-specific probes. These Rhodocyc...

  13. Enrichment of high ammonia tolerant methanogenic culture

    DEFF Research Database (Denmark)

    Fotidis, Ioannis; Karakashev, Dimitar Borisov; Proietti, Nicolas; Angelidaki, Irini

    Ammonia is the major toxicant in full scale anaerobic digesters of animal wastes which are rich in proteins and/or urea, such as pig or poultry wastes. Ammonia inhibition decreases methane production rates, increases volatile fatty acids concentration and leads to economic losses for the biogas...... plants. The methods used today to counteract ammonia inhibition are slow and costexpensive. A new biological approach to avoid or counteract ammonia inhibition by using ammonia tolerant methanogens, could provide a sustainable solution for cost-effective digestion of abundant ammonia-rich wastes. The aim...... of the current study was to isolate and identify methanogenic cultures tolerant to high ammonia concentrations. A mixed methanogenic population was stepwise exposed to ammonia concentrations (1 to 9.26 g NH4+-N L-1) during an enrichment process with successive batch cultivations. The methanogenic...

  14. 21 CFR 866.2330 - Enriched culture medium.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Enriched culture medium. 866.2330 Section 866.2330 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2330 Enriched...

  15. Enrichment and Short Term Culture of the Ovine Gonocyte

    Directory of Open Access Journals (Sweden)

    Rongfeng Li

    2011-01-01

    Full Text Available The aim of this study was to investigate the effects of two types of ovine testis cells population as feeder cell on in vitro culture of the enriched ovine gonocytes. The feeder cell populations were prepared from 5-6 months old ovine testis. The 1-2 months old neonatal rams were used to isolate germ cells through a two step enzymatic digestion followed by differential plating for SSCs enrichment. Isolated and enriched cells were characterized by using PLZF and VASA antibody. During the 1st week of culture, gonocyte formed pairs and chains of type A spermatogonia. After 1 week, colonies started to increase in size. About 2 weeks later, more colonies in type II feeder group kept undifferentiated and looks more effective regarding colony formation of spermatogonia compared with type I feeder group in the ovine spermatogonial stem cell culture system.

  16. Enrichment and microbial characterization of syngas converting anaerobic cultures

    OpenAIRE

    Alves, J.I.; Visser, Michael; A. J. M. Stams; Plugge, Caroline M.; Alves, M. M.; Sousa, D. Z.

    2013-01-01

    Bioconversion of recalcitrant biomass/waste into bulk chemicals or biofuels is often not feasible. By gasification of these materials, syngas (mainly composed of CO2, CO and H2) is generated and can be used for the production of high value compounds by thermochemical or biotechnological processes. Here, three thermophilic cultures enriched with syngas mixtures or pure CO (T-Syn, T-Syn-CO and T-CO) were studied. Stable enriched cultures obtained by subsequent transfers for over a year, convert...

  17. Absence of microbial mineralization of lignin in anaerobic enrichment cultures.

    OpenAIRE

    Odier, E; Monties, B

    1983-01-01

    The existence of anaerobic biodegradation of lignin was examined in mixed microflora. Egyptian soil samples, in which rapid mineralization of organic matter takes place in the presence of an important anaerobic microflora, were used to obtain the anaerobic enrichment cultures for this study. Specifically, 14CO2 or [14C]lignin wood was used to investigate the release of labeled gaseous or soluble degradation products of lignin in microbial cultures. No conversion of 14C-labeled lignin to 14CO2...

  18. Methanogenic degradation of acetone by an enrichment culture

    OpenAIRE

    Platen, Harald; Schink, Bernhard

    1987-01-01

    An anaerobic enrichment culture degraded 1 mol of acetone to 2 tool of methane and 1 tool of carbon dioxide. Two microorganisms were involved in this process, a filament-forming rod similar to Methanothrix sp. and an unknown rod with round to slightly pointed ends. Both organisms formed aggregates up to 300 gm in diameter. No fluorescing bacteria were observed indicating that hydrogen or formate-utilizing methanogens are not involved in this process. Acetate was utilized in this culture by th...

  19. Immunological identification and distribution of dissimilatory heme cd1 and nonheme copper nitrite reductases in denitrifying bacteria.

    OpenAIRE

    Coyne, M S; Arunakumari, A; Averill, B A; Tiedje, J.M.

    1989-01-01

    Polyclonal antibodies were used to identify heme or copper nitrite reductases in the following groups: 23 taxonomically diverse denitrifiers from culture collections, 100 numerically dominant denitrifiers from geographically diverse environments, and 51 denitrifiers from a culture collection not selected for denitrification. Antisera were raised against heme nitrite reductases from Pseudomonas aeruginosa and Pseudomonas stutzeri and against copper nitrite reductase from Achromobacter cyclocla...

  20. Chloroform degradation in methanogenic methanol enrichment cultures and by Methanosarcina barkeri 227.

    OpenAIRE

    Bagley, D M; Gossett, J M

    1995-01-01

    The effects of methanol addition and consumption on chloroform degradation rate and product distribution in methanogenic methanol enrichment cultures and in cultures of Methanosarcina barkeri 227 were investigated. Degradation of chloroform with initial concentrations up to 27.3 microM in enrichment cultures and 4.8 microM in pure cultures was stimulated by the addition of methanol. However, methanol consumption was inhibited by as little as 2.5 microM chloroform in enrichment cultures and 0....

  1. Anaerobic oxidation of acetylene by estuarine sediments and enrichment cultures

    Science.gov (United States)

    Culbertson, Charles W.; Zehnder, Alexander J. B.; Oremland, Ronald S.

    1981-01-01

    Acetylene disappeared from the gas phase of anaerobically incubated estuarine sediment slurries, and loss was accompanied by increased levels of carbon dioxide. Acetylene loss was inhibited by chloramphenicol, air, and autoclaving. Addition of 14C2H2 to slurries resulted in the formation of 14CO2 and the transient appearance of 14C-soluble intermediates, of which acetate was a major component. Acetylene oxidation stimulated sulfate reduction; however, sulfate reduction was not required for the loss of C2H2 to occur. Enrichment cultures were obtained which grew anaerobically at the expense of C2H2.

  2. Anaerobic oxidation of acetylene by estuarine sediments and enrichment cultures

    International Nuclear Information System (INIS)

    Acetylene disappeared from the gas phase of anaerobically incubated estuarine sediment slurries, and loss was accompanied by increased levels of carbon dioxide. Acetylene loss was inhibited by chloroamphenicol, air, and autoclaving. Addition of 14C2H2 to slurries resulted in the formation of 14CO2 and the transient appearance of 14C-soluble intermediates, of which acetate was a major component. Acetylene oxidation stimulated sulfate reduction; however, sulfate reduction was not required for the loss of C2H2 to occur. Enrichment cultures were obtained which grew anaerobically at the expense of C2H2

  3. Dimethylamine biodegradation by mixed culture enriched from drinking water biofilter.

    Science.gov (United States)

    Liao, Xiaobin; Chen, Chao; Zhang, Jingxu; Dai, Yu; Zhang, Xiaojian; Xie, Shuguang

    2015-01-01

    Dimethylamine (DMA) is one of the important precursors of drinking water disinfection by-product N-nitrosodimethylamine (NDMA). Reduction of DMA to minimize the formation of carcinogenic NDMA in drinking water is of practical importance. Biodegradation plays a major role in elimination of DMA pollution in the environment, yet information on DMA removal by drinking water biofilter is still lacking. In this study, microcosms with different treatments were constructed to investigate the potential of DMA removal by a mixed culture enriched from a drinking water biofilter and the effects of carbon and nitrogen sources. DMA could be quickly mineralized by the enrichment culture. Amendment of a carbon source, instead of a nitrogen source, had a profound impact on DMA removal. A shift in bacterial community structure was observed with DMA biodegradation, affected by carbon and nitrogen sources. Proteobacteria was the predominant phylum group in DMA-degrading microcosms. Microorganisms from a variety of bacterial genera might be responsible for the rapid DMA mineralization. PMID:25280176

  4. Effect of Enrichment Medium on Real-time Detection of Salmonella enterica from Lettuce and Tomato Enrichment Cultures

    Science.gov (United States)

    vThree commonly used enrichment broths for detection of Salmonella (Buffered Peptone Water – BPW, Tryptic Soy Broth – TSB, and Universal Preenrichment Broth – UPB) were compared for use in real time SYBR Green PCR detection of Salmonella introduced into enrichment cultures made from store bought let...

  5. Complete Genome Sequence of Bacteroidales Strain CF from a Chloroform-Dechlorinating Enrichment Culture

    OpenAIRE

    Tang, Shuiquan; Edwards, Elizabeth A.

    2013-01-01

    Bacteroidales strain CF is the most abundant nondechlorinating organism in a Dehalobacter-containing enrichment culture that consistently reductively dechlorinates >50 mg/liter chloroform or 1,1,1-trichloroethane (methyl chloroform). We assembled and closed the complete genome sequence of this organism from the metagenomic sequencing data for enrichment cultures. This organism is predicted to ferment l-lactate and ethanol.

  6. Tetrachloroethene transformation to trichloroethene and cis-1,2-dichloroethene by sulfate-reducing enrichment cultures.

    OpenAIRE

    Bagley, D M; Gossett, J M

    1990-01-01

    Tetrachloroethene, also known as perchloroethylene, was reductively dechlorinated to trichloroethene and cis-1,2-dichloroethene by laboratory sulfate-reducing enrichment cultures. The causative organism or group was not identified. However, tetrachloroethene was dechlorinated to trichloroethene in 50 mM bromoethane-sulfonate-inhibited enrichments and to trichloroethene and cis-1,2-dichloroethene in 3 mM fluoroacetate-inhibited enrichments. Overall transformation varied from 92% tetrachloroeth...

  7. Utilization of aminoaromatic acids by a methanogenic enrichment culture and by a novel Citrobacter freundii strain

    OpenAIRE

    Savelieva, O.; Kotova, I.; Roelofsen, W; A. J. M. Stams; Netrusov, A.

    2004-01-01

    Following incubation of mesophilic methanogenic floccular sludge from a lab-scale upflow anaerobic sludge bed reactor used to treat cattle manure wastewater, a stable 5-aminosalicylate-degrading enrichment culture was obtained. Subsequently, a Citrobacter freundii strain, WA1, was isolated from the 5-aminosalicylate-degrading methanogenic consortium. The methanogenic enrichment culture degraded 5-aminosalicylate completely to CH4, CO2 and NH4 , while C. freundii strain WA1 reduced 5-aminosal...

  8. Enrichment methodology to increase the positivity of cultures from body fluids

    Scientific Electronic Library Online (English)

    Alessandra Valle, Daur; Francisco, Klimak Jr.; Laura Lúcia, Cogo; Gislene Diógenes, Botão; Cristina Leise Bastos, Monteiro; Libera Maria, Dalla Costa.

    2006-12-01

    Full Text Available Isolation and identification of etiological agents found in body fluids can be of critical importance for the recovery of patients suffering from potentially-severe infections, which are often followed by serious sequels. Eighty-two samples of different body fluids were analyzed using two different [...] methods: (1) the conventional culture method (agar plating) and (2) the enrichment culture technique, using the Bact/Alert® blood culture bottle. The number of positive cultures increased on average from 9.7% to 23.1% with the enrichment culture technique. Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus were the most frequently isolated bacteria. The enrichment method could provide a more accurate means the identifying etiological agents.

  9. Enrichment methodology to increase the positivity of cultures from body fluids

    Directory of Open Access Journals (Sweden)

    Alessandra Valle Daur

    2006-12-01

    Full Text Available Isolation and identification of etiological agents found in body fluids can be of critical importance for the recovery of patients suffering from potentially-severe infections, which are often followed by serious sequels. Eighty-two samples of different body fluids were analyzed using two different methods: (1 the conventional culture method (agar plating and (2 the enrichment culture technique, using the Bact/Alert® blood culture bottle. The number of positive cultures increased on average from 9.7% to 23.1% with the enrichment culture technique. Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus were the most frequently isolated bacteria. The enrichment method could provide a more accurate means the identifying etiological agents.

  10. Enhanced production and isotope enrichment of recombinant glycoproteins produced in cultured mammalian cells

    Energy Technology Data Exchange (ETDEWEB)

    Skelton, David; Goodyear, Abbey [Florida State University, Department of Chemistry and Biochemistry (United States); Ni, DaQun; Walton, Wendy J.; Rolle, Myron; Hare, Joan T. [Florida State University, Institute of Molecular Biophysics (United States); Logan, Timothy M., E-mail: tlogan@fsu.ed [Florida State University, Department of Chemistry and Biochemistry (United States)

    2010-10-15

    NMR studies of post-translationally modified proteins are complicated by the lack of an efficient method to produce isotope enriched recombinant proteins in cultured mammalian cells. We show that reducing the glucose concentration and substituting glutamate for glutamine in serum-free medium increased cell viability while simultaneously increasing recombinant protein yield and the enrichment of non-essential amino acids compared to culture in unmodified, serum-free medium. Adding dichloroacetate, a pyruvate dehydrogenase kinase inhibitor, further improves cell viability, recombinant protein yield, and isotope enrichment. We demonstrate the method by producing partially enriched recombinant Thy1 glycoprotein from Lec1 Chinese hamster ovary (CHO) cells using U-{sup 13}C-glucose and {sup 15}N-glutamate as labeled precursors. This study suggests that uniformly {sup 15}N,{sup 13}C-labeled recombinant proteins may be produced in cultured mammalian cells starting from a mixture of labeled essential amino acids, glucose, and glutamate.

  11. Enhanced production and isotope enrichment of recombinant glycoproteins produced in cultured mammalian cells

    International Nuclear Information System (INIS)

    NMR studies of post-translationally modified proteins are complicated by the lack of an efficient method to produce isotope enriched recombinant proteins in cultured mammalian cells. We show that reducing the glucose concentration and substituting glutamate for glutamine in serum-free medium increased cell viability while simultaneously increasing recombinant protein yield and the enrichment of non-essential amino acids compared to culture in unmodified, serum-free medium. Adding dichloroacetate, a pyruvate dehydrogenase kinase inhibitor, further improves cell viability, recombinant protein yield, and isotope enrichment. We demonstrate the method by producing partially enriched recombinant Thy1 glycoprotein from Lec1 Chinese hamster ovary (CHO) cells using U-13C-glucose and 15N-glutamate as labeled precursors. This study suggests that uniformly 15N,13C-labeled recombinant proteins may be produced in cultured mammalian cells starting from a mixture of labeled essential amino acids, glucose, and glutamate.

  12. Use of ?-hexachlorocyclohexane as a terminal electron acceptor by an anaerobic enrichment culture

    International Nuclear Information System (INIS)

    Highlights: ? Use of ?-hexachlorocyclohexane as a terminal electron acceptor was demonstrated. ? H2 served as the electron donor for an enrichment culture that dechlorinated ?-HCH. ? H2 consumption for acetogenesis and methanogenesis stopped in HEPES media. ? Addition of vancomycin significantly slowed the rate of ?-HCH dechlorination. ? Previously identified chlororespiring microbes were not detected in the enrichment. - Abstract: The use of ?-hexachlorocyclohexane (HCH) as a terminal electron acceptor via organohalide respiration was demonstrated for the first time with an enrichment culture grown in a sulfate-free HEPES-buffered anaerobic mineral salts medium. The enrichment culture was initially developed with soil and groundwater from an industrial site contaminated with HCH isomers, chlorinated benzenes, and chlorinated ethenes. When hydrogen served as the electron donor, 79–90% of the electron equivalents from hydrogen were used by the enrichment culture for reductive dechlorination of the ?-HCH, which was provided at a saturation concentration of approximately 10 mg/L. Benzene and chlorobenzene were the only volatile transformation products detected, accounting for 25% and 75% of the ?-HCH consumed (on a molar basis), respectively. The enrichment culture remained active with only hydrogen as the electron donor and ?-HCH as the electron acceptor through several transfers to fresh mineral salts medium for more than one year. Addition of vancomycin to the culture significantly slowed the rate of ?-HCH dechlorination, suggesting that a Gram-positive organism is responsible for the reduction of ?-HCH. Analysis of the ?-HCH dechlorinating enrichment culture did not detect any known chlororespiring genera, including Dehalobacter. In bicarbonate-buffered medium, reductive dechlorination of ?-HCH was accompanied by significant levels of acetogenesis as well as methanogenesis.

  13. Anaerobic degradation of isobutyrate by methanogenic enrichment cultures and by a Desuifococcus multivorans strain

    OpenAIRE

    Stieb, Marion; Schink, Bernhard

    1989-01-01

    Methanogenic enrichment cultures with isobuty-rate as sole source of carbon and energy were inoculated with sediment and sludge samples from freshwater and marine origin. Over more than 20 transfers, these cultures fermented 2 mol isobutyrate with 1 mol CO2 via an intermediate for-marion of n-butyrate to 4 mol acetate and 1 mol CH4. The primary isobutyrate-fermenting bacteria could not be purified. From one of the marine enrichment cultures, a sulfate-reducing bacterium was isolated which oxi...

  14. A strict anaerobic extreme thermophilic hydrogen-producing culture enriched from digested household waste

    DEFF Research Database (Denmark)

    Karakashev, Dimitar Borisov; Kotay, Shireen Meher; Trably, Eric; Angelidaki, Irini

    2009-01-01

    The aim of this study was to enrich, characterize and identify strict anaerobic extreme thermophilic hydrogen (H-2) producers from digested household solid wastes. A strict anaerobic extreme thermophilic H-2 producing bacterial culture was enriched from a lab-scale digester treating household...... wastes at 70 degrees C. The enriched mixed culture consisted of two rod-shaped bacterial members growing at an optimal temperature of 80 degrees C and an optimal pH 8.1. The culture was able to utilize glucose, galactose, mannose, xylose, arabinose, maltose, sucrose, pyruvate and glycerol as carbon...... from digested household wastes. This study provided a culture with a potential to be applied in reactor systems for extreme thermophilic H-2 production from complex organic wastes....

  15. Characteristics of enriched cultures for bio-huff-`n`-puff tests at Jilin oil field

    Energy Technology Data Exchange (ETDEWEB)

    Xiu-Yuan Wang; Gang Dai; Yan-Fen Xue; Shu-Hua Xie [Institute of Microbiology, Beijing (China)] [and others

    1995-12-31

    Three enriched cultures (48, 15a, and 26a), selected from more than 80 soil and water samples, could grow anaerobically in the presence of crude oil at 30{degrees}C and could ferment molasses to gases and organic acids. Oil recovery by culture 48 in the laboratory model experiment was enhanced by 25.2% over the original reserves and by 53.7% over the residual reserves. Enriched culture 48 was composed of at least 4 species belonging to the genera Eubacterium, Fusobacterium, and Bacteroides. This enriched culture was used as inoculum for MEOR field trials at Jilin oil field with satisfactory results. The importance of the role of these isolates in EOR was confirmed by their presence and behavior in the fluids produced from the microbiologically treated reservoir.

  16. Ca2+ enrichment in culture medium potentiates effect of oligonucleotides.

    Science.gov (United States)

    Hori, Shin-Ichiro; Yamamoto, Tsuyoshi; Waki, Reiko; Wada, Shunsuke; Wada, Fumito; Noda, Mio; Obika, Satoshi

    2015-10-30

    Antisense and RNAi-related oligonucleotides have gained attention as laboratory tools and therapeutic agents based on their ability to manipulate biological events in vitro and in vivo. We show that Ca(2+) enrichment of medium (CEM) potentiates the in vitro activity of multiple types of oligonucleotides, independent of their net charge and modifications, in various cells. In addition, CEM reflects in vivo silencing activity more consistently than conventional transfection methods. Microscopic analysis reveals that CEM provides a subcellular localization pattern of oligonucleotides resembling that obtained by unassisted transfection, but with quantitative improvement. Highly monodispersed nanoparticles ~100 nm in size are found in Ca(2+)-enriched serum-containing medium regardless of the presence or absence of oligonucleotides. Transmission electron microscopy analysis reveals that the 100-nm particles are in fact an ensemble of much smaller nanoparticles (ϕ ∼ 15 nm). The presence of these nanoparticles is critical for the efficient uptake of various oligonucleotides. In contrast, CEM is ineffective for plasmids, which are readily transfected via the conventional calcium phosphate method. Collectively, CEM enables a more accurate prediction of the systemic activity of therapeutic oligonucleotides, while enhancing the broad usability of oligonucleotides in the laboratory. PMID:26101258

  17. Effects of heat treatment on hydrogen production potential and microbial community of thermophilic compost enrichment cultures.

    Science.gov (United States)

    Nissilä, Marika E; Tähti, Hanne P; Rintala, Jukka A; Puhakka, Jaakko A

    2011-03-01

    Cellulosic plant and waste materials are potential resources for fermentative hydrogen production. In this study, hydrogen producing, cellulolytic cultures were enriched from compost material at 52, 60 and 70°C. Highest cellulose degradation and highest H(2) yield were 57% and 1.4 mol-H(2) mol-hexose(-1) (2.4 mol-H(2) mol-hexose-degraded(-1)), respectively, obtained at 52°C with the heat-treated (80°C for 20 min) enrichment culture. Heat-treatments as well as the sequential enrichments decreased the diversity of microbial communities. The enrichments contained mainly bacteria from families Thermoanaerobacteriaceae and Clostridiaceae, from which a bacterium closely related to Thermoanaerobium thermosaccharolyticum was mainly responsible for hydrogen production and bacteria closely related to Clostridium cellulosi and Clostridium stercorarium were responsible for cellulose degradation. PMID:21251819

  18. Transformations of Halogenated Aromatic Aldehydes by Metabolically Stable Anaerobic Enrichment Cultures

    OpenAIRE

    Neilson, Alasdair H.; Allard, Ann-Sofie; Hynning, Per-Åke; Remberger, Mikael

    1988-01-01

    Metabolically stable enrichment cultures of anaerobic bacteria obtained by elective enrichment of sediment samples from the Baltic Sea and Gulf of Bothnia have been used to study the oxidation and reduction of the aldehyde group of various halogenated aromatic aldehydes. During the transformation of 5- and 6-chlorovanillin, 6-bromovanillin, 3-chloro-4-hydroxybenzaldehyde, 3,5-dichloro-4-hydroxybenzaldehyde, and 3,5-dibromo-4-hydroxybenzaldehyde, it was shown that synthesis of the correspondin...

  19. Resource recovery from organic waste streams by microbial enrichment cultures:

    OpenAIRE

    Tamis, J.

    2015-01-01

    Polyhydroxyalkanoate (PHA) is a natural product that can potentially replace a part of the chemicals and plastics derived from fossil sources. One of the main barriers for market entry of PHA is its relatively high price compared to conventional (fossil) feedstocks. This high price is related to current industrial production methods which are based on the cultivation of pure microbial cultures of a single species that a.o. has to be protected from contaminations from unwanted microorganisms t...

  20. 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)

    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

  1. Two-stage mineralization of phenanthrene by estuarine enrichment cultures

    International Nuclear Information System (INIS)

    The polycyclic aromatic hydrocarbon phenanthrene was mineralized in two stages by soil, estuarine water, and sediment microbial populations. At high concentrations, phenanthrene was degraded, with the concomitant production of biomass and accumulation of Folin-Ciocalteau-reactive aromatic intermediates. Subsequent consumption of these intermediates resulted in a secondary increase in biomass. Analysis of intermediates by high-performance liquid chromatography, thin-layer chromatography, and UV absorption spectrometry showed 1-hydroxy-2-naphthoic acid (1H2NA) to be the predominant product. A less pronounced two-stage mineralization pattern was also observed by monitoring 14CO2 production from low concentrations (0.5 mg liter-1) of radiolabeled phenanthrene. Here, mineralization of 14C-labeled 1H2NA could explain the incremental 14CO2 produced during the later part of the incubations. Accumulation of 1H2NA by isolates obtained from enrichments was dependent on the initial phenanthrene concentration. The production of metabolites during polycyclic aromatic hydrocarbon biodegradation is discussed with regard to its possible adaptive significance and its methodological implications

  2. Anaerobic benzene degradation by iron- and sulfate-reducing enrichment cultures

    OpenAIRE

    Abu Laban, Nidal

    2010-01-01

    Anaerobic benzene degradation was studied with a sulfate- and an iron-reducing enrichment culture (BPL and BF). In culture BPL, molecular analysis revealed 95% dominance of a novel phylotype that is affiliated to the genus Pelotomaculum. To elucidate the initial activation mechanism of anaerobic benzene degradation, putative metabolites were screened revealing benzoate as a product of a carboxylation reaction. For identification of enzymes involved in anaerobic benzene degradation the whole p...

  3. CULTURAL ENRICHMENT THROUGH COMMUNITY ACTION PROJECT. ANNUAL REPORT FOR PERIOD ENDING JULY 1, 1967. (TITLE SUPPLIED).

    Science.gov (United States)

    WILSON, O.J.

    WESTERN KENTUCKY UNIVERSITY INITIATED A PROJECT TO DETERMINE THE CULTURAL NEEDS AND INTERESTS OF THE AREA IT SERVES. IN PHASE ONE, CITY AND COUNTY REPRESENTATIVES ATTENDED A SYMPOSIUM ON ART, MUSIC, LIBRARY, LECTURE, AND THEATER RESOURCES AND FORMED A REGIONAL ADVISORY COUNCIL FOR COMMUNITY ENRICHMENT. PHASE TWO WAS A WORKSHOP TO HELP COUNCIL…

  4. Who is actively denitrifying in activated sludge?

    DEFF Research Database (Denmark)

    Hansen, Aviaja Anna; Nielsen, Jeppe Lund

    2008-01-01

    Denitrification is of crucial importance in nitrogen removal from wastewater. However, due to the polyphyletic taxonomy of denitrifiers, little is known about the composition and ecophysiology of the actively denitrifying community in activated sludge. To identify the active denitrifiers in a full-scale wastewater treatment plant the transcripts (mRNA) of the nirS, nirK and nosZ denitrification genes expressed under acetate or amino acid consumption were amplified, sequenced and identified. This...

  5. BACTERIOLOGY OF BODY FLUIDS WITH AN EVALUATION OF ENRICHMENT TECHNIQUE TO INCREASE CULTURE POSITIVITY

    Directory of Open Access Journals (Sweden)

    Anasua

    2014-12-01

    Full Text Available BACKGROUND: Body fluids like ascitic fluids, pleural fluids, cerebrospinal fluids (CSF etc. are sent for culture in a clinical microbiology laboratory to achieve etiological diagnosis. However the yield of such cultures is usually very low. So, ongoing monitoring of prevalent pathogenic organisms and their sensitivities help the clinicians institute therapy in absence of a culture report. AIMS: The study was done to identify the common pathogens isolated from body fluids along with their antimicrobial susceptibility pattern and also to evaluate the impact of enrichment on their culture positivity. SETTING AND DESIGN: A 3-month prospective analytical study was done in a tertiary care hospital. MATERIALS AND METHODS: A total of 333 Body fluids were processed; 103 of them were ascitic fluids, 71 pleural fluids, 139 CSF and 20 other fluids. They were processed by plating the direct sample and after enrichment. Enrichment was done by two methods: in Soyabean-Caesin digest broth (274 samples and by BACTEC (59 samples.Isolates were identified by routine procedures & their antimicrobial susceptibility determined as per CLSI guidelines. The results were analyzed using Microsoft Excel® software using p<0.05 as the cut-off for significance. RESULTS: Gram negative isolate were obtained from 21.3% of the samples. The common isolates were Pseudomonas (20.7%, Acinetobacter (11.6%, Citrobacter (10.7% and E. coli (10.7%. The antibiotics most effective against Gram negative pathogens were Gentamicin (47.5%, Pipercillin-Tazobactam (51.6%, Amikacin (56.7% and Cefoperazone-Sulbactam(65.3%. Gram positive isolates, obtained from 9% of the samples, mostly consisted of MSSA, Enterococcus and CONS, for which Ciprofloxacin (48% followed by Cotrimoxazole (40% and Erythromycin (28.6% showed reasonable efficacy. The Culture positivity with direct plating, Soyabean-Caesin broth enrichment and BACTEC was 14.41%, 29.19% and 42.37% respectively. Increase in positivity by Soyabean-Casein broth was maximum for pleural fluids (12% followed by ascitic fluids (11.6% and CSF (11.52%.Using automated system the corresponding increases were 20.7%for ascitic fluids and 5.4%for pleural fluids. The mean time for identification using direct plating, enrichment method and BACTEC were 48 hours, 72 hours and 40 hours respectively. CONCLUSION: Gram negative isolates are commonly isolated pathogens from body fluids in our setup. Enrichment of body fluids improved yield of pathogens. In resource-poor settings simple enrichment in blood culture bottles can increase culture positivity of these precious samples.

  6. Identification of active denitrifiers in full-scale nutrient removal wastewater treatment systems.

    Science.gov (United States)

    McIlroy, Simon Jon; Starnawska, Anna; Starnawski, Piotr; Saunders, Aaron Marc; Nierychlo, Marta; Nielsen, Per Halkjaer; Nielsen, Jeppe Lund

    2016-01-01

    Denitrification is essential to the removal of nitrogen from wastewater during treatment, yet an understanding of the diversity of the active denitrifying bacteria responsible in full-scale wastewater treatment plants (WWTPs) is lacking. In this study, stable-isotope probing (SIP) was applied in combination with microautoradiography (MAR)-fluorescence in situ hybridization (FISH) to identify previously unrecognized active denitrifying phylotypes in a full-scale WWTP with biological N and P removal. Acknowledging that different denitrifiers will have specific carbon source preferences, a fully (13) C-labelled complex substrate was used for SIP incubations, under nitrite-reducing conditions, in order to maximize the capture of the potentially metabolically diverse denitrifiers likely present. Members of the Rhodoferax,?Dechloromonas, Sulfuritalea,?Haliangium and Thermomonas were represented in the 16S rRNA gene clone libraries from DNA enriched in (13) C, with FISH probes optimized here for their in situ characterization. FISH and MAR confirmed that they were all active denitrifiers in the community. The combined approach of SIP and MAR-FISH represents an excellent approach for identifying and characterizing an un-described diversity of active denitrifiers in full-scale systems. PMID:25181571

  7. Identification of active denitrifiers in full-scale nutrient removal wastewater treatment systems

    DEFF Research Database (Denmark)

    McIlroy, Simon Jon; Szyszka, Anna

    2015-01-01

    Denitrification is essential to the removal of nitrogen from wastewater during treatment, yet an understanding of the diversity of the active denitrifying bacteria responsible in full-scale wastewater treatment plants (WWTP) is lacking. In this study stable isotope probing (SIP) was applied in combination with microautoradiography (MAR)-fluorescence in situ hybridisation (FISH) to identify the active denitrifiers in a full-scale WWTP with biological N and P removal. Recognising that a range of carbon sources likely drive denitrification, a fully 13 C-labelled complex substrate was used for SIP incubations, under nitrite reducing conditions, in order to better capture the diversity of active denitrifiers present. Members of the Rhodoferax, Dechloromonas and Sulfuritalea were well represented in the 16S rRNA gene clone libraries from DNA enriched in 13 C, with FISH probes designed here for their in situ characterisation. FISH and MAR confirmed that they were core active denitrifiers in the community. The SIP clone library was additionally represented by a phylogenetically diverse group of organisms, with many previously not considered as important denitrifiers. The combined approach of SIP and MAR-FISH represents an excellent approach for identifying and characterising un-described diversity of active denitrifiers in full-scale systems.

  8. Oxygen regulation of nitrate uptake in denitrifying Pseudomonas aeruginosa.

    OpenAIRE

    Hernandez, D; Rowe, J J

    1987-01-01

    Oxygen had an immediate and reversible inhibitory effect on nitrate respiration by denitrifying cultures of Pseudomonas aeruginosa. Inhibition of nitrate utilization by oxygen appeared to be at the level of nitrate uptake, since nitrate reduction to nitrite in cell extracts was not affected by oxygen. The degree of oxygen inhibition was dependent on the concentration of oxygen, and increasing nitrate concentrations could not overcome the inhibition. The inhibitory effect of oxygen was maximal...

  9. Ammonia tolerant enriched methanogenic cultures as bioaugmentation inocula to alleviate ammonia inhibition in continuous anaerobic reactors

    DEFF Research Database (Denmark)

    Fotidis, Ioannis; Wang, Han; Angelidaki, Irini

    ammonia tolerant methanogen in a CSTR reactor could completely alleviate the ammonia inhibitory effect. Furthermore, it was found that bioaugmentation with the enriched culture resulted in 25% higher methane production compared to when the bioaugmentation was achieved with pure methanogenic strains. The...... methanogens are more robust to ammonia toxicity effect. It has been shown that bioaugmentation of a pure strain of a hydrogenotrophic methanogen (i.e. Methanoculleus bourgensis) in an ammonia inhibited continuous anaerobic reactor can improve methane production more than 30%. Nevertheless, cultivation of a...... tolerant methanogenic culture as potential bioaugmentation inoculum in a continuous stirred tank reactor (CSTR) operating under “inhibited steady-state”, triggered by high ammonia levels (5 g NH4+-N L-1). The results of the current study established for the first time that bioaugmentation of an enriched...

  10. Degradation of unsaturated hydrocarbons by methanogenic enrichment cultures : (Aromatic compounds; alcohol degradation; hexadecene; squalene; hydratation; carboxylation)

    OpenAIRE

    Schink, Bernhard

    1985-01-01

    The biodegradability of hydrocarbons under anaerobic conditions was studied in enrichment cultures using mineral media inoculated with sewage sludge or sediment samples of limnic and marine origin. No indication of methanogenic degradation was obtained with either n-hexane, n-hexadecane, n-heptadecane, 1-hexene, cis-2-hexene, trans-2-hexene, isoprene, 1-hexine, benzene, toluene, xylene, cyclohexene, cycloheptatriene, cyclopentadiene, styrene, naphthalene, azulene, or fl-carotene. Squalene was...

  11. Metabolic by-products of anaerobic toluene degradation by sulfate-reducing enrichment cultures.

    OpenAIRE

    Beller, H. R.; Reinhard, M.; Grbić-Galić, D

    1992-01-01

    Two dead-end metabolites of anaerobic toluene transformation, benzylsuccinic acid and benzylfumaric acid, accumulated in sulfate-reducing enrichment cultures that were fed toluene as the sole carbon source. Stable isotope-labeled toluene and gas chromatography-mass spectrometry were used to confirm that the compounds resulted from toluene metabolism. The two metabolites constituted less than 10% of the toluene carbon (over 80% was mineralized to carbon dioxide, according to a previous study)....

  12. Comparative analysis of metagenomes from three methanogenic hydrocarbon-degrading enrichment cultures with 41 environmental samples.

    Science.gov (United States)

    Tan, Boonfei; Fowler, S Jane; Abu Laban, Nidal; Dong, Xiaoli; Sensen, Christoph W; Foght, Julia; Gieg, Lisa M

    2015-09-01

    Methanogenic hydrocarbon metabolism is a key process in subsurface oil reservoirs and hydrocarbon-contaminated environments and thus warrants greater understanding to improve current technologies for fossil fuel extraction and bioremediation. In this study, three hydrocarbon-degrading methanogenic cultures established from two geographically distinct environments and incubated with different hydrocarbon substrates (added as single hydrocarbons or as mixtures) were subjected to metagenomic and 16S rRNA gene pyrosequencing to test whether these differences affect the genetic potential and composition of the communities. Enrichment of different putative hydrocarbon-degrading bacteria in each culture appeared to be substrate dependent, though all cultures contained both acetate- and H2-utilizing methanogens. Despite differing hydrocarbon substrates and inoculum sources, all three cultures harbored genes for hydrocarbon activation by fumarate addition (bssA, assA, nmsA) and carboxylation (abcA, ancA), along with those for associated downstream pathways (bbs, bcr, bam), though the cultures incubated with hydrocarbon mixtures contained a broader diversity of fumarate addition genes. A comparative metagenomic analysis of the three cultures showed that they were functionally redundant despite their enrichment backgrounds, sharing multiple features associated with syntrophic hydrocarbon conversion to methane. In addition, a comparative analysis of the culture metagenomes with those of 41 environmental samples (containing varying proportions of methanogens) showed that the three cultures were functionally most similar to each other but distinct from other environments, including hydrocarbon-impacted environments (for example, oil sands tailings ponds and oil-affected marine sediments). This study provides a basis for understanding key functions and environmental selection in methanogenic hydrocarbon-associated communities. PMID:25734684

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-08-01

    The degradation of several munitions compounds was studied. The compounds included 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine, octahydro-1,3,5,7-tetranitro-1,3,5,7-tetraazocine, 2,4,6-trinitrobenzene (TNB), and 2,4-dinitrotoluene. All of the compounds studied were degraded by the sulfate reducing bacterial (SRB) enrichment culture. The SRB culture did not use the munitions compounds as their sole source of carbon. However, all the munitions compounds tested served as the sole source of nitrogen for the SRB culture. Degradation of munitions compounds was achieved by a co-metabolic process. The SRB culture used a variety of carbon sources including pyruvate, ethanol, formate, lactate, and H{sub 2}-CO{sub 2}. The SRB culture was an incomplete oxidizer, unable to carry out the terminal oxidation of organic substrates to CO{sub 2} as the sole product, and it did not use acetate or methanol as a carbon source. In addition to serving as nitrogen sources, the munitions compounds also served as electron acceptors in the absence of sulfate. A soil slurry experiment with 5% and 10% munitions compounds-contaminated soil showed that the contaminant TNT was metabolized by the SRB culture in the presence of pyruvate as electron donor. This culture may be useful in decontaminating munitions compounds-contaminated soil and water under anaerobic conditions.

  14. Metabolic characteristics of an aerobe isolated from a methylotrophic methanogenic enrichment culture

    Indian Academy of Sciences (India)

    Stephen V Rapheal; K R Swaminathan; K Lalitha

    2003-03-01

    An anaerobic methylotrophic methanogenic enrichment culture, with sustained metabolic characteristics, including that of methanation for over a decade, was the choice of the present study on interspecies interactions. Growth and methanation by the enrichment were suppressed in the presence of antibiotics, and no methanogen grown on methanol could be isolated using stringent techniques. The present study confirmed syntrophic metabolic interactions in this enrichment with the isolation of a strain of Pseudomonas sp. The organism had characteristic metabolic versatility in metabolizing a variety of substrates including alcohols, aliphatic acids, amino acids, and sugars. Anaerobic growth was favoured with nitrate in the growth medium. Cells grown anaerobically with methanol, revealed maximal nitrate reductase activity. Constitutive oxidative activity of the membrane system emerged from the high-specific oxygen uptake and nitrate reductase activities of the aerobically and anerobically grown cells respectively. Cells grown anaerobically on various alcohols effectively oxidized methanol in the presence of flavins, cofactor FAD and the methanogenic cofactor F420, suggesting a constitutive alcohol oxidizing capacity. In cells grown anaerobically on methanol, the rate of methanol oxidation with F420 was three times that of FAD. Efficient utilization of alcohols in the presence of F420 is a novel feature of the present study. The results suggest that utilization of methanol by the mixed culture would involve metabolic interactions between the Pseudomonas sp. and the methanogen(s). Methylotrophic, methanogenic partnership involving an aerobe is a novel feature hitherto unreported among anaerobic syntrophic associations and is of ecological significance.

  15. Bacterial community analysis of cypermethrin enrichment cultures and bioremediation of cypermethrin contaminated soils.

    Science.gov (United States)

    Akbar, Shamsa; Sultan, Sikander; Kertesz, Michael

    2015-07-01

    Cypermethrin is widely used for insect control; however, its toxicity toward aquatic life requires its complete removal from contaminated areas where the natural degradation ability of microbes can be utilized. Agricultural soil with extensive history of CM application was used to prepare enrichment cultures using cypermethrin as sole carbon source for isolation of cypermethrin degrading bacteria and bacterial community analysis using PCR-DGGE of 16?S rRNA gene. DGGE analysis revealed that dominant members of CM enrichment culture were associated with ?-proteobacteria followed by ?-proteobacteria, Firmicutes, and Actinobacteria. Three potential CM-degrading isolates identified as Ochrobactrum anthropi JCm1, Bacillus megaterium JCm2, and Rhodococcus sp. JCm5 degraded 86-100% of CM (100?mg?L(-1) ) within 10 days. These isolates were also able to degrade other pyrethroids, carbofuran, and cypermethrin degradation products. Enzyme activity assays revealed that enzymes involved in CM-degradation were inducible and showed activity when strains were grown on cypermethrin. Degradation kinetics of cypermethrin (200?mg?kg(-1)) in soils inoculated with isolates JCm1, JCm2, and JCm5 suggested time-dependent disappearance of cypermethrin with rate constants of 0.0516, 0.0425, and 0.0807?d(-1), respectively, following first order rate kinetics. The isolated bacterial strains were among dominant genera selected under CM enriched conditions and represent valuable candidates for in situ bioremediation of contaminated soils and waters. PMID:25656248

  16. Tetrachloromethane-Degrading Bacterial Enrichment Cultures and Isolates from a Contaminated Aquifer

    Directory of Open Access Journals (Sweden)

    Christian Penny

    2015-07-01

    Full Text Available The prokaryotic community of a groundwater aquifer exposed to high concentrations of tetrachloromethane (CCl4 for more than three decades was followed by terminal restriction fragment length polymorphism (T-RFLP during pump-and-treat remediation at the contamination source. Bacterial enrichments and isolates were obtained under selective anoxic conditions, and degraded 10 mg·L?1 CCl4, with less than 10% transient formation of chloroform. Dichloromethane and chloromethane were not detected. Several tetrachloromethane-degrading strains were isolated from these enrichments, including bacteria from the Klebsiella and Clostridium genera closely related to previously described CCl4 degrading bacteria, and strain TM1, assigned to the genus Pelosinus, for which this property was not yet described. Pelosinus sp. TM1, an oxygen-tolerant, Gram-positive bacterium with strictly anaerobic metabolism, excreted a thermostable metabolite into the culture medium that allowed extracellular CCl4 transformation. As estimated by T-RFLP, phylotypes of CCl4-degrading enrichment cultures represented less than 7%, and archaeal and Pelosinus strains less than 0.5% of the total prokaryotic groundwater community.

  17. Establishment and Characterization of an Anaerobic Thermophilic (55 degrees C) Enrichment Culture Degrading Long-Chain Fatty Acids

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Ahring, Birgitte Kiær

    1995-01-01

    A thermophilic, long-chain fatty acid-oxidizing culture was enriched. Stearate was used as the substrate, and methane and carbon dioxide were the sole end products. Cultivation was possible only when a fed-batch system was used or with addition of activated carbon or bentonite. The enrichment...

  18. Integrated biogas upgrading and hydrogen utilization in an anaerobic reactor containing enriched hydrogenotrophic methanogenic culture

    DEFF Research Database (Denmark)

    Luo, Gang; Angelidaki, Irini

    2012-01-01

    existing natural gas grid. The current study presents a new biological method for biogas upgrading in a separate biogas reactor, containing enriched hydrogenotrophic methanogens and fed with biogas and hydrogen. Both mesophilic- and thermophilic anaerobic cultures were enriched to convert CO2 to CH4 by...... by PCR–DGGE. Nonetheless, they all belonged to the order Methanobacteriales, which can mediate hydrogenotrophic methanogenesis. Biogas upgrading was then tested in a thermophilic anaerobic reactor under various operation conditions. By continuous addition of hydrogen in the biogas reactor, high...... degree of biogas upgrading was achieved. The produced biogas had a CH4 content, around 95% at steady-state, at gas (mixture of biogas and hydrogen) injection rate of 6 L/(L day). The increase of gas injection rate to 12 L/(L day) resulted in the decrease of CH4 content to around 90%. Further study showed...

  19. Establishment and Characterization of an Anaerobic Thermophilic (55(deg)C) Enrichment Culture Degrading Long-Chain Fatty Acids

    OpenAIRE

    Angelidaki, I.; Ahring, B K

    1995-01-01

    A thermophilic, long-chain fatty acid-oxidizing culture was enriched. Stearate was used as the substrate, and methane and carbon dioxide were the sole end products. Cultivation was possible only when a fed-batch system was used or with addition of activated carbon or bentonite. The enrichment culture consisted of a short rod and two bacteria antigenically related to Methanobacterium thermoautotrophicum (Delta)H and Methanosarcina thermophila TM-1.

  20. Metatranscriptome of an Anaerobic Benzene-Degrading, Nitrate-Reducing Enrichment Culture Reveals Involvement of Carboxylation in Benzene Ring Activation

    OpenAIRE

    LUO, Fei; Gitiafroz, Roya; Devine, Cheryl E.; Gong, Yunchen; Hug, Laura A; Raskin, Lutgarde; Edwards, Elizabeth A.

    2014-01-01

    The enzymes involved in the initial steps of anaerobic benzene catabolism are not known. To try to elucidate this critical step, a metatranscriptomic analysis was conducted to compare the genes transcribed during the metabolism of benzene and benzoate by an anaerobic benzene-degrading, nitrate-reducing enrichment culture. RNA was extracted from the mixed culture and sequenced without prior mRNA enrichment, allowing simultaneous examination of the active community composition and the different...

  1. Establishment and Characterization of an Anaerobic Thermophilic (55 degrees C) Enrichment Culture Degrading Long-Chain Fatty Acids

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Ahring, Birgitte Kiær

    1995-01-01

    A thermophilic, long-chain fatty acid-oxidizing culture was enriched. Stearate was used as the substrate, and methane and carbon dioxide were the sole end products. Cultivation was possible only when a fed-batch system was used or with addition of activated carbon or bentonite. The enrichment culture consisted of a short rod and two bacteria antigenically related to Methanobacterium thermoautotrophicum DELTA-H and Methanosarcina thermophila TM-1.

  2. Establishment and Characterization of an Anaerobic Thermophilic (55 degrees C) Enrichment Culture Degrading Long-Chain Fatty Acids

    OpenAIRE

    Angelidaki, Irini; Ahring, Birgitte Kiær

    2012-01-01

    A thermophilic, long-chain fatty acid-oxidizing culture was enriched. Stearate was used as the substrate, and methane and carbon dioxide were the sole end products. Cultivation was possible only when a fed-batch system was used or with addition of activated carbon or bentonite. The enrichment culture consisted of a short rod and two bacteria antigenically related to Methanobacterium thermoautotrophicum DELTA-H and Methanosarcina thermophila TM-1.

  3. Inhibition of anaerobic ammonium oxidizing (anammox) enrichment cultures by substrates, metabolites and common wastewater constituents.

    Science.gov (United States)

    Carvajal-Arroyo, José M; Sun, Wenjie; Sierra-Alvarez, Reyes; Field, Jim A

    2013-03-01

    Anaerobic ammonium oxidation (anammox) is an emerging technology for nitrogen removal that provides a more environmentally sustainable and cost effective alternative compared to conventional biological treatment methods. The objective of this study was to investigate the inhibitory impact of anammox substrates, metabolites and common wastewater constituents on the microbial activity of two different anammox enrichment cultures (suspended and granular), both dominated by bacteria from the genus Brocadia. Inhibition was evaluated in batch assays by comparing the N(2) production rates in the absence or presence of each compound supplied in a range of concentrations. The optimal pH was 7.5 and 7.3 for the suspended and granular enrichment cultures, respectively. Among the substrates or products, ammonium and nitrate caused low to moderate inhibition, whereas nitrite caused almost complete inhibition at concentrations higher than 15 mM. The intermediate, hydrazine, either stimulated or caused low inhibition of anammox activity up to 3mM. Of the common constituents in wastewater, hydrogen sulfide was the most severe inhibitor, with 50% inhibitory concentrations (IC(50)) as low as 0.03 mM undissociated H(2)S. Dissolved O(2) showed moderate inhibition (IC(50)=2.3-3.8 mg L(-1)). In contrast, phosphate and salinity (NaCl) posed very low inhibition. The suspended- and granular anammox enrichment cultures had similar patterns of response to the various inhibitory stresses with the exception of phosphate. The findings of this study provide comprehensive insights on the tolerance of the anammox process to a wide variety of potential inhibiting compounds. PMID:23245574

  4. Large scale production of Blackleg vaccine by fermenter and enriched culture medium in Iran

    Directory of Open Access Journals (Sweden)

    Pilehchian Langroudi, R.

    2012-06-01

    Full Text Available In all biological systems growth is defined as increase of chemical compounds. Bacteria can achieve to balanced growth if they are growing in a medium, which are completely adapted to it. Clostridium chauvoei, (Clostridium feseri is an anaerobic, spore forming, motile, and polymorph bacteria, which its size varies from 0.5-1 to 3-8 micron and could be observed as individual bacterium, diplo, and rarely streptococcus. Blackleg is a fatal disease of young cattle. It produces an acute local infection, and the resulting blood poisoning leads to rapid death. Clostridium chauvoei and, less frequently, Clostridium septicum are the most commonly responsible organisms. Vaccination is the only effective means for controlling of blackleg disease. Several kinds of vaccine are available commercially. It is 4 decades that blackleg vaccine is produced in Razi institute and because of enhanced demand of country, decision was made to improve the production procedure of this vaccine using large-scale fermenter, so the aim of this study was adaptation of Clostridium chauvoei to growth and proliferation in fermenter for preparation of a potent vaccine. Accordingly attempts were made to prepare and formulate the ingredients in order to obtain high yield of Clostridium chauvoei in culture medium by fermenter. All experiments were done in two sets: A-growth in glass bottles using conventional culture medium and B-growth in fermenter using conventional culture medium similar to A and also enriched culture medium. Results showed high yield of Clostridium chauvoei suspension in fermenter after 10 hours, using enriched culture medium (more than 1,480,000,000 organisms/ml, but no significant changes was obtained in glass bottles conditions comparing to the fermenter conditions. The safety and potency of the prepared vaccine was determined in sheep and guinea pigs according to British pharmacopoeia (veterinary with satisfactory results. Since this research has been successfully done in Razi research institute, so the mono valent inactivated blackleg vaccine, using the enriched culture medium is currently producing by fermenter and is used for immunization of cattles in Iran.

  5. Denitrifying Bacteria in the Earthworm Gastrointestinal Tract and In Vivo Emission of Nitrous Oxide (N(inf2)O) by Earthworms

    OpenAIRE

    Karsten, G. R.; H. L. Drake

    1997-01-01

    Earthworms (Lumbricus rubellus and Octolasium lacteum) and gut homogenates did not produce CH(inf4), and methanogens were not readily culturable from gut material. In contrast, the numbers of culturable denitrifiers averaged 7 x 10(sup7) and 9 x 10(sup6) per g (dry weight) of gut material for L. rubellus and O. lacteum, respectively; these values were 256- and 35-fold larger than the numbers of culturable denitrifiers in the soil from which the earthworms were obtained. Anaerobically incubate...

  6. Comparison of bacterial enriched-broth culture, enzyme linked immunosorbent assay, and broth culture-polymerase chain reaction techniques for identifying asymptomatic infections with Salmonella in swine

    OpenAIRE

    Sibley, Jennifer; Yue, Binbin; Huang, Fei; Harding, John; Kingdon, Jill; Chirino-Trejo, Manuel; Appleyard, Greg D.

    2003-01-01

    A polymerase chain reaction (PCR) assay was combined with a broth-culture enrichment system to detect Salmonella shed in feces from subclinically infected swine. The effectiveness of the broth culture-polymerase chain reaction (BC-PCR) assay to identify pigs shedding Salmonella in feces was compared with a microbiological culture and a commercial enzyme linked immunosorbent assay (ELISA) kit to detect Salmonella-specific serum antibody. A total of 67 pigs were tested by each of the 3 methodol...

  7. Bacterial oxidation of dibromomethane and methyl bromide in natural waters and enrichment cultures

    Science.gov (United States)

    Goodwin, K.D.; Schaefer, J.K.; Oremland, R.S.

    1998-01-01

    Bacterial oxidation of 14CH2Br2 and 14CH3Br was measured in freshwater, estuarine, seawater, and hypersaline-alkaline samples. In general, bacteria from the various sites oxidized similar amounts of 14CH2Br2 and comparatively less 14CH3Br. Bacterial oxidation of 14CH3Br was rapid in freshwater samples compared to bacterial oxidation of 14CH3Br in more saline waters. Freshwater was also the only site in which methyl fluoride-sensitive bacteria (e.g., methanotrophs or nitrifiers) governed brominated methane oxidation. Half-life calculations indicated that bacterial oxidation of CH2Br2 was potentially significant in all of the waters tested. In contrast, only in freshwater was bacterial oxidation of CH3Br as fast as chemical removal. The values calculated for more saline sites suggested that bacterial oxidation of CH3Br was relatively slow compared to chemical and physical loss mechanisms. However, enrichment cultures demonstrated that bacteria in seawater can rapidly oxidize brominated methanes. Two distinct cultures of nonmethanotrophic methylotrophs were recovered; one of these cultures was able to utilize CH2Br2 as a sole carbon source, and the other was able to utilize CH3Br as a sole carbon source.

  8. Functional gene pyrosequencing and network analysis: an approach to examine the response of denitrifying bacteria to increased nitrogen supply in salt marsh sediments

    Directory of Open Access Journals (Sweden)

    JenniferL.Bowen

    2013-11-01

    Full Text Available Functional gene pyrosequencing is emerging as a useful tool to examine the diversity and abundance of microbes that facilitate key biogeochemical processes. One such process, denitrification, is of particular importance because it converts fixed nitrate (NO3- to N2 gas, which returns to the atmosphere. In N limited salt marshes, removal of NO3- prior to entering adjacent waters helps prevent eutrophication. Understanding the dynamics of salt marsh microbial denitrification is thus imperative for the maintenance of healthy coastal ecosystems. We used pyrosequencing of the nirS gene to examine the denitrifying community response to fertilization in experimentally enriched marsh plots. A key challenge in the analysis of sequence data derived from pyrosequencing is understanding whether small differences in gene sequences are ecologically meaningful. We apply a novel approach from information theory that determined that the optimal similarity level for clustering DNA sequences into OTUs, while still capturing the ecological complexity of the system, was 88% similarity. With this clustering, phylogenetic analysis yielded 6 dominant clades of denitrifiers, the largest of which, accounting for more than half of all the sequences collected, had no close cultured representatives. Of the 638 OTUs identified, only 11 were present in all plots and no single OTU was dominant. We did, however, find a large number of specialist OTUs that were present only in a single plot. The high degree of endemic OTUs, while accounting for a large proportion of the nirS diversity in the plots, were found in lower abundance than the generalist taxa. The proportion of specialist taxa increased with increasing supply of nutrients, suggesting that addition of fertilizer may create conditions that expand the niche space for denitrifying organisms and may enhance the genetic capacity for denitrification.

  9. Selective enrichment and production of highly urease active bacteria by non-sterile (open) chemostat culture.

    Science.gov (United States)

    Cheng, Liang; Cord-Ruwisch, Ralf

    2013-10-01

    In general, bioprocesses can be subdivided into naturally occurring processes, not requiring sterility (e.g., beer brewing, wine making, lactic acid fermentation, or biogas digestion) and other processes (e.g., the production of enzymes and antibiotics) that typically require a high level of sterility to avoid contaminant microbes overgrowing the production strain. The current paper describes the sustainable, non-sterile production of an industrial enzyme using activated sludge as inoculum. By using selective conditions (high pH, high ammonia concentration, and presence of urea) for the target bacterium, highly active ureolytic bacteria, physiologically resembling Sporosarcina pasteurii were reproducibly enriched and then continuously produced via chemostat operation of the bioreactor. When using a pH of 10 and about 0.2 M urea in a yeast extract-based medium, ureolytic bacteria developed under aerobic chemostat operation at hydraulic retention times of about 10 h with urease levels of about 60 ?mol min?¹ ml?¹ culture. For cost minimization at an industrial scale the costly protein-rich yeast extract medium could be replaced by commercial milk powder or by lysed activated sludge. Glutamate, molasses, or glucose-based media did not result in the enrichment of ureolytic bacteria by the chemostat. The concentration of intracellular urease was sufficiently high such that the produced raw effluent from the reactor could be used directly for biocementation in the field. PMID:23892419

  10. Fermentative bio-hydrogen production from cellulose by cow dung compost enriched cultures

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Nan-Qi; Xu, Ji-Fei; Gao, Ling-Fang; Xin, Liang; Qiu, Jie; Su, Dong-Xia [State Key Laboratory of Urban Water Resources and Environment, Harbin Institute of Technology, Harbin 150090 (China)

    2010-04-15

    The performance of hydrogen production from cellulose by the cow dung compost enriched continuously in defined medium containing cellulose was investigated. In the initial experiments, batch-fermentation was carried out to observe the effects of different substrate concentration conditions on the rate of cellulose-degrading, growth of bacteria and the capability of hydrogen-producing from cellulose. The result showed that the cellulose degradation decreased from 55% at 5 g/l to 22% at 30 g/l. The maximum cumulative hydrogen production and the rate of hydrogen production first increased from 828 ml/l at 5 g/l to 1251 ml/l at 10 g/l then remained constant beyond 10 g/l. The maximum hydrogen production potential, the rate of hydrogen production and the yield of hydrogen was 1525 ml/l, 33 ml/l.h, and 272 ml/g-cellulose (2.09 mol/mol-hexose) was obtained at substrate concentration 10 g/l, the hydrogen concentration in biogas was 47-50%(v/v) and there was no methane observed. During the conversion of cellulose into hydrogen, acetate and butyrate were main liquid end-products in the metabolism of hydrogen fermentation. These results proposed that cow dung compost enriched cultures were ideal microflora for hydrogen production from cellulose. (author)

  11. Selective enrichment yields robust ethene-producing dechlorinating cultures from microcosms stalled at cis-dichloroethene.

    Science.gov (United States)

    Delgado, Anca G; Kang, Dae-Wook; Nelson, Katherine G; Fajardo-Williams, Devyn; Miceli, Joseph F; Done, Hansa Y; Popat, Sudeep C; Krajmalnik-Brown, Rosa

    2014-01-01

    Dehalococcoides mccartyi strains are of particular importance for bioremediation due to their unique capability of transforming perchloroethene (PCE) and trichloroethene (TCE) to non-toxic ethene, through the intermediates cis-dichloroethene (cis-DCE) and vinyl chloride (VC). Despite the widespread environmental distribution of Dehalococcoides, biostimulation sometimes fails to promote dechlorination beyond cis-DCE. In our study, microcosms established with garden soil and mangrove sediment also stalled at cis-DCE, albeit Dehalococcoides mccartyi containing the reductive dehalogenase genes tceA, vcrA and bvcA were detected in the soil/sediment inocula. Reductive dechlorination was not promoted beyond cis-DCE, even after multiple biostimulation events with fermentable substrates and a lengthy incubation. However, transfers from microcosms stalled at cis-DCE yielded dechlorination to ethene with subsequent enrichment cultures containing up to 10(9) Dehalococcoides mccartyi cells mL(-1). Proteobacterial classes which dominated the soil/sediment communities became undetectable in the enrichments, and methanogenic activity drastically decreased after the transfers. We hypothesized that biostimulation of Dehalococcoides in the cis-DCE-stalled microcosms was impeded by other microbes present at higher abundances than Dehalococcoides and utilizing terminal electron acceptors from the soil/sediment, hence, outcompeting Dehalococcoides for H2. In support of this hypothesis, we show that garden soil and mangrove sediment microcosms bioaugmented with their respective cultures containing Dehalococcoides in high abundance were able to compete for H2 for reductive dechlorination from one biostimulation event and produced ethene with no obvious stall. Overall, our results provide an alternate explanation to consolidate conflicting observations on the ubiquity of Dehalococcoides mccartyi and occasional stalling of dechlorination at cis-DCE; thus, bringing a new perspective to better assess biological potential of different environments and to understand microbial interactions governing bioremediation. PMID:24950250

  12. Real-time PCR detection of Campylobacter spp.: A comparison to classic culturing and enrichment.

    Science.gov (United States)

    de Boer, P; Rahaoui, H; Leer, R J; Montijn, R C; van der Vossen, J M B M

    2015-10-01

    The major disadvantage of the current gold standard for detection of the food pathogen Campylobacter, i.e. culturing, is the lengthy procedure. In this study we assessed the use of real-time PCR for detection of Campylobacter. To this end, 926 poultry samples, taken from transport containers and broiler caeca in The Netherlands in 2007, were subjected to three different real-time PCR detection methods: one targeting the Campylobacter jejuni hipO gene, one targeting the Campylobacter coli glyA gene, and one generically targeting Campylobacter spp. 16S rDNA sequence. The PCR results from the three different PCR protocols were compared to the work of Nauta et al. (2009) who analyzed the same set of samples collected from 62 broiler flocks by means of enrichment culturing. The results indicate that the generic 16S campylobacter PCR detection is equally reliable but much faster (4 h instead of ?2 days) than detection by means of culturing. Moreover, PCR detection targeting the hipO and the glyA gene provide the possibility of C. jejuni and C. coli species discrimination. The generic Campylobacter spp. PCR analysis also confirmed the high incidence of Campylobacter spp. in poultry samples (?90%) and the species specific PCR showed the simultaneous presence of C. jejuni and C. coli in ?24% of the samples. Furthermore, the results from the three PCR analyses suggested the occurrence of alternative Campylobacter species in almost 10% of the samples. The campylobacter PCR detection methods reported here can replace traditional culturing because of being quicker and more reliable. PMID:26187833

  13. Enrichment and characterization of MTBE-degrading cultures under iron and sulfate reducing conditions

    Energy Technology Data Exchange (ETDEWEB)

    Raynal, M. [Univ. Nacional Autonoma de Mexico, Mexico City (Mexico). Inst. de Ingenieria; Crimi, B. [Delft Univ. of Technology (Netherlands). Dept. of Biotechnology; Pruden, A. [Virginia Tech, Blacksburg, VA (United States). Dept. of Civil and Environmental Engineering

    2010-04-15

    Methyl tert-butyl ether (MTBE) is widely used as an additive to gasoline. It has been exposed to the environment as a result of releases from underground storage tanks and pipelines. MTBE has been banned or limited in many areas of North America because of its high aqueous solubility and slow biodegradation rate. The aim of this study was to obtain highly enriched consortia capable of the anaerobic biodegradation of MTBE. Amplified 16S rDNA restriction-digest analysis (ARDRA) was used to identify the sequencing of unique 16S rRNA genes. The study examined sulfate- and iron-reducing conditions as electron acceptors in groundwater. The aqueous cultures were inoculated in 3 different growth media to examine the effect of biodegradation. Between 5 to 8 members were identified in 3 consortia. A clone was detected in cultures containing iron. Results indicated that the buildup of intermediates and the presence of sulfides inhibited biodegradation. The results may provide biomarkers to support current anaerobic MTBE biodegradation field studies. 80 refs., 1 tab., 3 figs.

  14. High yield derivation of enriched glutamatergic neurons from suspension-cultured mouse ESCs for neurotoxicology research

    Directory of Open Access Journals (Sweden)

    Hubbard Kyle S

    2012-10-01

    Full Text Available Abstract Background Recently, there has been a strong emphasis on identifying an in vitro model for neurotoxicity research that combines the biological relevance of primary neurons with the scalability, reproducibility and genetic tractability of continuous cell lines. Derived neurons should be homotypic, exhibit neuron-specific gene expression and morphology, form functioning synapses and consistently respond to neurotoxins in a fashion indistinguishable from primary neurons. However, efficient methods to produce neuronal populations that are suitable alternatives to primary neurons have not been available. Methods With the objective of developing a more facile, robust and efficient method to generate enriched glutamatergic neuronal cultures, we evaluated the neurogenic capacity of three mouse embryonic stem cell (ESC lines (R1, C57BL/6 and D3 adapted to feeder-independent suspension culture. Neurogenesis and neuronal maturation were characterized as a function of time in culture using immunological, genomic, morphological and functional metrics. The functional responses of ESNs to neurotropic toxins with distinctly different targets and mechanisms of toxicity, such as glutamate, ?-latrotoxin (LTX, and botulinum neurotoxin (BoNT, were also evaluated. Results Suspension-adapted ESCs expressed markers of pluripotency through at least 30 passages, and differentiation produced 97×106 neural progenitor cells (NPCs per 10-cm dish. Greater than 99% of embryonic stem cell-derived neurons (ESNs expressed neuron-specific markers by 96 h after plating and rapidly developed complex axodendritic arbors and appropriate compartmentalization of neurotypic proteins. Expression profiling demonstrated the presence of transcripts necessary for neuronal function and confirmed that ESN populations were predominantly glutamatergic. Furthermore, ESNs were functionally receptive to all toxins with sensitivities and responses consistent with primary neurons. Conclusions These findings demonstrate a cost-effective, scalable and flexible method to produce a highly enriched glutamatergic neuron population. The functional characterization of pathophysiological responses to neurotropic toxins and the compatibility with multi-well plating formats were used to demonstrate the suitability of ESNs as a discovery platform for molecular mechanisms of action, moderate-throughput analytical approaches and diagnostic screening. Furthermore, for the first time we demonstrate a cell-based model that is sensitive to all seven BoNT serotypes with EC50 values comparable to those reported in primary neuron populations. These data providing compelling evidence that ESNs offer a neuromimetic platform suitable for the evaluation of molecular mechanisms of neurotoxicity.

  15. Addition of novobiocin in pre-enrichment step can improve Salmonella culture protocol of modified semisolid Rappaport-Vassiliadis

    DEFF Research Database (Denmark)

    Jensen, Annette Nygaard; Sørensen, Gitte; Baggesen, Dorte Lau; Bødker, Rene; Hoorfar, Jeffrey

    2003-01-01

    , 90 samples opposed to 50 yielded a strong positive reading (+++) when Novobiocin was applied. Growth was on average 0.3 scores higher when pre-enriched with Novobiocin. The difference in growth score medians of the two methods was highly significant (Sign test; p <0.001). Despite the increased...... pre-enrichment broth with BPW made semi-selective by addition of Novobiocin. The semi-quantitative assessment of the Salmonella level showed that addition of Novobiocin in the pre-enrichment step on average increased the level of Salmonella 1.2 log dilution steps. When growth was scored at five levels...... sensitivity, 13 culture-positive samples were missed when using the Novobiocin-containing BPW. In conclusion, a simple addition of Novobiocin in the BPW pre-enrichment step of fecal samples may facilitate reading and thereby detection of Salmonella on MSRV. The increase of Salmonella in the semi...

  16. Chronic impact of tetracycline on nitrification kinetics and the activity of enriched nitrifying microbial culture.

    Science.gov (United States)

    Katipoglu-Yazan, Tugce; Merlin, Christophe; Pons, Marie-Noëlle; Ubay-Cokgor, Emine; Orhon, Derin

    2015-04-01

    This study evaluated the chronic impact of tetracycline on biomass with enriched nitrifying community sustained in a lab-scale activated sludge system. For this purpose, a fill and draw reactor fed with 100 mg COD/L of peptone mixture and 50 mg N/L of ammonia was sustained at a sludge age of 15 days. At steady-state, the reactor operation was continued with a daily tetracycline dosing of 50 mg/L for more than 40 days, with periodic monitoring of the microbial composition, the nitrifying bacteria abundance, as well as the amoA and 16S rRNA gene activity, using molecular techniques. Changes in the kinetics of nitrification were quantified by modelling concentration profiles of major nitrogen fractions and oxygen uptake rate profiles derived from parallel batch experiments. Activated sludge modeling results indicated inhibitory impact of tetracycline on the growth of nitrifiers with a significant increase of the half saturation coefficients in corresponding rate equations. Tetracycline also inactivated biomass components of the enriched culture at a gradually increasing rate with time of exposure, leading to total collapse of nitrification. Molecular analyses revealed significant changes in the composition of the microbial community throughout the observation period. They also showed that continuous exposure to tetracycline inflicted significant reduction in amoA mRNA and 16S rRNA levels directly affecting nitrification. The chronic impact was much more pronounced on the ammonia oxidizing bacteria (AOB) community. These observations explained the basis of numerical changes identified in the growth kinetics of nitrifiers under stress conditions. PMID:25616640

  17. High molecular weight dissolved organic matter enrichment selects for methylotrophs in dilution to extinction cultures.

    Science.gov (United States)

    Sosa, Oscar A; Gifford, Scott M; Repeta, Daniel J; DeLong, Edward F

    2015-12-01

    The role of bacterioplankton in the cycling of marine dissolved organic matter (DOM) is central to the carbon and energy balance in the ocean, yet there are few model organisms available to investigate the genes, metabolic pathways, and biochemical mechanisms involved in the degradation of this globally important carbon pool. To obtain microbial isolates capable of degrading semi-labile DOM for growth, we conducted dilution to extinction cultivation experiments using seawater enriched with high molecular weight (HMW) DOM. In total, 93 isolates were obtained. Amendments using HMW DOM to increase the dissolved organic carbon concentration 4x (280??M) or 10x (700??M) the ocean surface water concentrations yielded positive growth in 4-6% of replicate dilutions, whereas <1% scored positive for growth in non-DOM-amended controls. The majority (71%) of isolates displayed a distinct increase in cell yields when grown in increasing concentrations of HMW DOM. Whole-genome sequencing was used to screen the culture collection for purity and to determine the phylogenetic identity of the isolates. Eleven percent of the isolates belonged to the gammaproteobacteria including Alteromonadales (the SAR92 clade) and Vibrio. Surprisingly, 85% of isolates belonged to the methylotrophic OM43 clade of betaproteobacteria, bacteria thought to metabolically specialize in degrading C1 compounds. Growth of these isolates on methanol confirmed their methylotrophic phenotype. Our results indicate that dilution to extinction cultivation enriched with natural sources of organic substrates has a potential to reveal the previously unsuspected relationships between naturally occurring organic nutrients and the microorganisms that consume them. PMID:25978545

  18. Sustained growth of explants from Mediterranean sponge Crambe crambe cultured in vitro with enriched RPMI 1640.

    Science.gov (United States)

    Garcia Camacho, F; Chileh, T; Cerón García, M C; Sanchez Mirón, A; Belarbi, E H; Contreras Gómez, A; Molina Grima, E

    2006-01-01

    Marine sponges are potential sources of many unique metabolites, including cytotoxic and anticancer compounds. Natural sponge populations are insufficient or inaccessible for producing commercial quantities of metabolites of interest. It is commonly accepted that tissue (fragments, explants, and primmorphs) and in vitro cell cultivation show great potential. However, there is little knowledge of the nutritional requirements of marine sponges to carry out efficient and sustained in vitro culture and progress has been slow. In marine invertebrate fila many unsuccessful attempts have been made with in vitro cultures using typical commercial animal cell media based on sources of dissolved organic carbon (DOC) (e.g., DMEM, RPMI, M199, L-15, etc.). One of the reasons for this failure is the use of hardly identifiable growth promoters, based on terrestrial animal sera. An alternative is the use of extracts from marine animals, since they may contain nutrients necessary for growth. In this work we have cultivated in vitro explants of the encrusting marine sponge Crambe crambe. It is one of the most abundant sponges on the Mediterranean coastline and also possesses an array of potentially active metabolites (crambines and crambescidins). Initially a new approach was developed in order to show consumption of DOC by explants. Thus, different initial DOC concentrations (300, 400, 700 and 1200 mg DOC L(-1)) were assayed. Consumption was evident in all four assays and was more marked in the first 6 h. The DOC assimilation data were adjusted to an empirical model widely used for uptake kinetics of organic dissolved compounds in marine invertebrates. Second, a protocol was established to cultivate explants in vitro. Different medium formulations based on RPMI 1640 commercial medium enriched with amino acids and inorganic salts to emulate seawater salinity were assayed. The enrichment of this medium with an Octopus aqueous extract in the proportions of 10% and 20% (v/v) resulted in an evident sustained long-term growth of C. crambe explants. This growth enhancement produced high metabolic activity in the explants, as is confirmed by the high ammonium and lactate content in the medium a few days after its renewal and by the consumption of glucose. The lactate accumulation increased with the size and age of explants. Prior to these experiments, we successfully developed a robust new alternative method, based on digital image treatment, for accurate determination of the explant apparent volume as growth measure. PMID:16739962

  19. Vertical Distribution of Soil Denitrifying Communities in a Wet Sclerophyll Forest under Long-Term Repeated Burning.

    Science.gov (United States)

    Liu, Xian; Chen, Chengrong; Wang, Weijin; Hughes, Jane M; Lewis, Tom; Hou, Enqing; Shen, Jupei

    2015-11-01

    Soil biogeochemical cycles are largely mediated by microorganisms, while fire significantly modifies biogeochemical cycles mainly via altering microbial community and substrate availability. Majority of studies on fire effects have focused on the surface soil; therefore, our understanding of the vertical distribution of microbial communities and the impacts of fire on nitrogen (N) dynamics in the soil profile is limited. Here, we examined the changes of soil denitrification capacity (DNC) and denitrifying communities with depth under different burning regimes, and their interaction with environmental gradients along the soil profile. Results showed that soil depth had a more pronounced impact than the burning treatment on the bacterial community size. The abundance of 16S rRNA and denitrification genes (narG, nirK, and nirS) declined exponentially with soil depth. Surprisingly, the nosZ-harboring denitrifiers were enriched in the deeper soil layers, which was likely to indicate that the nosZ-harboring denitrifiers could better adapt to the stress conditions (i.e., oxygen deficiency, nutrient limitation, etc.) than other denitrifiers. Soil nutrients, including dissolved organic carbon (DOC), total soluble N (TSN), ammonium (NH4 (+)), and nitrate (NO3 (-)), declined significantly with soil depth, which probably contributed to the vertical distribution of denitrifying communities. Soil DNC decreased significantly with soil depth, which was negligible in the depths below 20 cm. These findings have provided new insights into niche separation of the N-cycling functional guilds along the soil profile, under a varied fire disturbance regime. PMID:26066514

  20. Platelet-activating factor increases prostaglandin E(2) release from astrocyte-enriched cortical cell cultures.

    Science.gov (United States)

    Teather, Lisa A; Lee, Robert K K; Wurtman, Richard J

    2002-08-01

    The phospholipid mediator platelet-activating factor (PAF) increased the release of prostaglandin E(2) (PGE(2)) from astrocyte-enriched cortical cell cultures in a concentration- and time-dependent manner. The nonhydrolyzable PAF analog methylcarbamyl-PAF (mc-PAF), the PAF intermediate lyso-PAF, and arachidonic acid (AA) also produced this effect. In contrast, phosphatidlycholine (PC) and lyso-PC, lipids that are structurally similar to PAF and lyso-PAF, had no effect on PGE(2) production, suggesting that PAF-induced PGE(2) release is not the consequence of nonspecific phospholipid-induced membrane perturbation. Antagonism of intracellular PAF binding sites completely abolished the ability of mc-PAF and lyso-PAF to mobilize PGE(2,) and attenuated the AA effect. Antagonism of the G-protein-coupled PAF receptor in plasma membranes had no significant effect on mc-PAF, lyso-PAF or AA-induced PGE(2) release. Based on the present findings, we hypothesize that intracellular PAF is a physiologic stimulus of PGE(2) production in astrocytes. PMID:12133598

  1. Diversity of reductive dehalogenase genes from environmental samples and enrichment cultures identified with degenerate primer PCR screens.

    Directory of Open Access Journals (Sweden)

    LauraAudreyHug

    2013-11-01

    Full Text Available Reductive dehalogenases are the critical enzymes for anaerobic organohalide respiration, a microbial metabolic process that has been harnessed for bioremediation efforts to resolve chlorinated solvent contamination in groundwater and is implicated in the global halogen cycle. Reductive dehalogenase sequence diversity is informative for the dechlorination potential of the site or enrichment culture. A suite of degenerate PCR primers targeting a comprehensive curated set of reductive dehalogenase genes was designed and applied to twelve DNA samples extracted from contaminated and pristine sites, as well as six enrichment cultures capable of reducing chlorinated compounds to non-toxic end-products. The amplified gene products from four environmental sites and two enrichment cultures were sequenced using Illumina HiSeq, and the reductive dehalogenase complement of each sample determined. The results indicate that the diversity of the reductive dehalogenase gene family is much deeper than is currently accounted for: one-third of the translated proteins have less than 70% pairwise amino acid identity to database sequences. Approximately 60% of the sequenced reductive dehalogenase genes were broadly distributed, being identified in four or more samples, and often in previously sequenced genomes as well. In contrast, 17% of the sequenced reductive dehalogenases were unique, present in only a single sample and bearing less than 90% pairwise amino acid identity to any previously identified proteins. Many of the broadly distributed reductive dehalogenases are uncharacterized in terms of their substrate specificity, making these intriguing targets for further biochemical experimentation. Finally, comparison of samples from a contaminated site and an enrichment culture derived from the same site eight years prior allowed examination of the effect of the enrichment process.

  2. Passive markers as a low-cost method of enriching cultural visits on user’s demand

    Directory of Open Access Journals (Sweden)

    Anestis Koutsoudis

    2014-01-01

    Full Text Available The idea of enriching a cultural heritage visitor’s experience by employing mobile devices such as smartphones and tablets is an active research domain. This is mainly due to the worldwide user penetration of such devices along with their continuous hardware performance enhancement. This work presents the experience and feedback gained by one year of operation of an experimental information system that aims in enhancing the experience of a visitor on his/her demand. The evaluated system is based on the use case-scenario where the a mobile device is used to capture and decode passive markers (such as QR-codes that are located on facades of selected important buildings in the old town of Xanthi, Greece, in order to enrich the visitor’s experience through a broad context of historical and architectural information delivered over the Web.   Keywords: On-demand information, Passive marker, QR-code, Smartphone, Visit enrichment.

  3. Distribution of nitrogenous nutrients and denitrifiers strains in estuarine sediment profiles of the Tanshui River, northern Taiwan

    Science.gov (United States)

    Fan, L. F.; Shieh, W. Y.; Wu, W. F.; Chen, C.-P.

    2006-09-01

    Chemical profiles of both oxidized (nitrate and sulfate) and reduced (ammonium, sulfide, acid-volatile sulfide [AVS], and pyrite) materials and the corresponding distribution of denitrifier microbial communities were measured at low tide in sediments at Guandu in the estuary of the Tanshui River, northern Taiwan in August 2002. Denitrifier strains were isolated for physiological and phylogenic analyses. Based on the distribution of nitrogenous compounds and denitrifier abundances, the vertical profile of Guandu sediments could be separated into four layers: a mixed layer (the top 1 cm of depth, respectively containing 0.82-2.37 and 535.9-475.0 ?M of nitrate and ammonium), a nitrate-concentrated layer (1-5 cm in depth, 2.37-0.53 and 475.0-1192.1 ?M, respectively), a denitrifier-aggregation layer (5-7 cm in depth, 0.53-0.72 and 1192.1-1430.1 ?M, respectively), and an ammonium-enriched layer (7-12 cm in depth, 0.72-0.78 and 1430.1-2196.6 ?M, respectively). Denitrifier strains were detected in all layers except for the mixed layer. A variety of metabolic processes by these strains may occur in different layers. Bacillus jeotgali-, Bacillus sphaericus-, and Bacillus firmus-related strains isolated from the nitrate-concentrated layer may be involved in the nitrification-denitrification coupling process due to the relatively low nitrate concentrations (maximum = 2.37 ?M), and may contribute to denitrification not nitrification. Bacillus bataviensis- and B. jeotgali-related strains isolated from the denitrifier-aggregation layer comprised the predominant denitrifier population (3.64 × 10 4 cells/g of denitrifier abundance). They possess the ability of dissimilatory nitrate reduction to ammonium (DNRA). Bacillus jeotgali-related strains and two newly identified strains of GD0705 and GD0706 isolated from the ammonium-enriched layer possibly use fermentative processes as the main metabolic pathway instead of denitrification when nitrate is scarce, and this further supports the high ammonium concentrations (up to 2.20 mM) found in the Guandu sediments. In addition, spore formation also enhances the chance of survival of these strains in the face with such a nitrate-deficient environment.

  4. PCR amplification of Bartonella koehlerae from human blood and enrichment blood cultures

    Directory of Open Access Journals (Sweden)

    Breitschwerdt Edward B

    2010-08-01

    Full Text Available Abstract Background Cats appear to be the primary reservoir host for Bartonella koehlerae, an alpha Proteobacteria that is most likely transmitted among cat populations by fleas (Ctenocephalides felis. Bartonella koehlerae has caused endocarditis in a dog and in one human patient from Israel, but other clinically relevant reports involving this bacterium are lacking. Despite publication of numerous, worldwide epidemiological studies designed to determine the prevalence of Bartonella spp. bacteremia in cats, B. koehlerae has never been isolated using conventional blood agar plates. To date, successful isolation of B. koehlerae from cats and from the one human endocarditis patient has consistently required the use of chocolate agar plates. Results In this study, Bartonella koehlerae bacteremia was documented in eight immunocompetent patients by PCR amplification and DNA sequencing, either prior to or after enrichment blood culture using Bartonella alpha Proteobacteria growth medium. Presenting symptoms most often included fatigue, insomnia, joint pain, headache, memory loss, and muscle pain. Four patients were also infected with Bartonella vinsonii subsp. berkhoffii genotype II. After molecular documentation of B. koehlerae infection in these patients, a serological test was developed and serum samples were tested retrospectively. Bartonella koehlerae antibodies were not detected (titers B. koehlerae antibody titers of 1:64 or greater. Conclusions Although biased by a study population consisting of individuals with extensive arthropod and animal exposure, the results of this study suggest that B. koehlerae bacteremia is more common in immunocompetent people than has been previously suspected. Future studies should more thoroughly define modes of transmission and risk factors for acquiring infection with B. koehlerae. In addition, studies are needed to determine if B. koehlerae is a cause or cofactor in the development of arthritis, peripheral neuropathies or tachyarrhythmias in patients.

  5. Bacterial community analysis in chlorpyrifos enrichment cultures via DGGE and use of bacterial consortium for CP biodegradation.

    Science.gov (United States)

    Akbar, Shamsa; Sultan, Sikander; Kertesz, Michael

    2014-10-01

    The organophosphate pesticide chlorpyrifos (CP) has been used extensively since the 1960s for insect control. However, its toxic effects on mammals and persistence in environment necessitate its removal from contaminated sites, biodegradation studies of CP-degrading microbes are therefore of immense importance. Samples from a Pakistani agricultural soil with an extensive history of CP application were used to prepare enrichment cultures using CP as sole carbon source for bacterial community analysis and isolation of CP metabolizing bacteria. Bacterial community analysis (denaturing gradient gel electrophoresis) revealed that the dominant genera enriched under these conditions were Pseudomonas, Acinetobacter and Stenotrophomonas, along with lower numbers of Sphingomonas, Agrobacterium and Burkholderia. Furthermore, it revealed that members of Bacteroidetes, Firmicutes, ?- and ?-Proteobacteria and Actinobacteria were present at initial steps of enrichment whereas ?-Proteobacteria appeared in later steps and only Proteobacteria were selected by enrichment culturing. However, when CP-degrading strains were isolated from this enrichment culture, the most active organisms were strains of Acinetobacter calcoaceticus, Pseudomonas mendocina and Pseudomonas aeruginosa. These strains degraded 6-7.4 mg L(-1) day(-1) of CP when cultivated in mineral medium, while the consortium of all four strains degraded 9.2 mg L(-1) day(-1) of CP (100 mg L(-1)). Addition of glucose as an additional C source increased the degradation capacity by 8-14 %. After inoculation of contaminated soil with CP (200 mg kg(-1)) disappearance rates were 3.83-4.30 mg kg(-1) day(-1) for individual strains and 4.76 mg kg(-1) day(-1) for the consortium. These results indicate that these organisms are involved in the degradation of CP in soil and represent valuable candidates for in situ bioremediation of contaminated soils and waters. PMID:25008559

  6. The influence of fertilization on the quantitative distribution of denitrifying bacteria in the soil

    OpenAIRE

    Simona Dunca; Marius Stefan; Mariana Murgoci

    2010-01-01

    Highlighting the processes by which the nitrogen compounds are reduced in the soil (i.e. denitrification) and which result in the increase of the ammonium level, is extremely important since denitrification is one of the effective mechanisms that reduce the nitrogen content in the soils rich in nitrites thus preventing soil pollution. The determination of the most probable number of denitrifying bacteria was carried out by the multiple tube technique using Allen’s culture medium, ...

  7. Assessing the influence of CH4 concentration during culture enrichment on the biodegradation kinetics and population structure.

    Science.gov (United States)

    López, Juan C; Quijano, Guillermo; Pérez, Rebeca; Muñoz, Raúl

    2014-12-15

    Methanotrophic communities were enriched in three stirred tank reactors continuously supplied with CH4-laden air at 20, 2 and 0.2 gCH4 m(-3) in order to evaluate the influence of CH4 concentration on the biodegradation kinetics, population structure and potential polyhydroxyalkanoate production under sequential nitrogen limitations. The population structure of the enriched cultures, dominated by type I methanotrophs, was influenced by CH4 concentration. No significant correlation between CH4 concentration and the maximum specific degradation rate (qmax) or the half-saturation constant (KS) was recorded, microorganisms enriched at 2 gCH4 m(-3) presenting the highest qmax and those enriched at 20 and 0.2 gCH4 m(-3) exhibiting the lowest KS. Maximum polyhydroxybutyrate (PHB) contents of 1.0% and 12.6% (w/w) were achieved at 20 and 2 g CH4 m(-3), respectively. Polyhydroxyvalerate (PHV) was also detected at PHV:PHB ratios of up to 12:1 and 4:1 in the communities enriched at 20 and 0.2 gCH4 m(-3), respectively. PMID:25169644

  8. Preparation of Glycerol-Enriched Yeast Culture and Its Effect on Blood Metabolites and Ruminal Fermentation in Goats

    OpenAIRE

    Ye, Gengping; Zhu, Yongxing; Liu, Jin; Chen, Xingxiang; Huang, Kehe

    2014-01-01

    The aim of this study was to isolate a glycerol-producing yeast strain from nature to prepare glycerol-enriched yeast culture (GY), and preliminarily evaluate the effects of GY on blood metabolites and ruminal fermentation in goats. During the trial, six isolates were isolated from unprocessed honey, and only two isolates with higher glycerol yield were identified by analysis of 26S ribosomal DNA sequences. One of the two isolates was identified as Saccharomyces cerevisiae, a direct-fed micro...

  9. Anaerobic Degradation of Benzene, Toluene, Ethylbenzene, and o-Xylene in Sediment-Free Iron-Reducing Enrichment Cultures

    OpenAIRE

    Jahn, Michael K.; Haderlein, Stefan B.; Meckenstock, Rainer U.

    2005-01-01

    Monoaromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene (BTEX) are widespread contaminants in groundwater. We examined the anaerobic degradation of BTEX compounds with amorphous ferric oxide as electron acceptor. Successful enrichment cultures were obtained for all BTEX substrates both in the presence and absence of AQDS (9,10-anthraquinone-2,6-disulfonic acid). The electron balances showed a complete anaerobic oxidation of the aromatic compounds to CO2. This is the first...

  10. Atrazine biodegradation efficiency, metabolite detection, and trzD gene expression by enrichment bacterial cultures from agricultural soil

    OpenAIRE

    Solomon, Robinson David Jebakumar; Kumar, Amit; Satheeja Santhi, Velayudhan

    2013-01-01

    Atrazine is a selective herbicide used in agricultural fields to control the emergence of broadleaf and grassy weeds. The persistence of this herbicide is influenced by the metabolic action of habituated native microorganisms. This study provides information on the occurrence of atrazine mineralizing bacterial strains with faster metabolizing ability. The enrichment cultures were tested for the biodegradation of atrazine by high-performance liquid chromatography (HPLC) and mass spectrometry. ...

  11. Formation of spontaneous hematopoietic colonies in semisolid cultures of lymphocyte enriched fractions of peripheral blood from beagles

    International Nuclear Information System (INIS)

    The formation of hematopoietic colonies in semisolid cultures derived from lymphocyte enriched fractions of canine peripheral blood is described. Such colonies occurred in the absence of either mitogens or colony stimulating factor. Although the mechanism(s) involved in such colony formation is not known, preliminary results suggest an increased tendency for spontaneous colony formation with age and a possible relationship to low-level irradiation and neoplasia. The observation underlines the importance of doing nonmitogen stimulated control cultures in order to determine the true influence of mitogens or growth factors on colony formation

  12. Degradation of polycyclic aromatic hydrocarbons by microbial consortia enriched from three soils using two different culture media

    International Nuclear Information System (INIS)

    A consortium composed of many different bacterial species is required to efficiently degrade polycyclic aromatic hydrocarbons (PAH) in oil-contaminated soil. We obtained six PAH-degrading microbial consortia from three oil-contaminated soils using two different isolation culture media. Denaturing gradient gel electrophoresis (DGGE) and sequence analyses of amplified 16s rRNA genes confirmed the bacterial community was greatly affected by both the culture medium and the soil from which the consortia were enriched. Three bacterial consortia enriched using malt yeast extract (MYE) medium showed higher degradation rates of PAHs than consortia enriched using Luria broth (LB) medium. Consortia obtained from a soil and then added back to that same soil was more effective in degrading PAHs than adding, to the same soil, consortia isolated from other, unrelated soils. This suggests that inoculum used for bioremediation should be from the same, or very similar nearby soils, as the soil that is actually being bioremediated. -- Highlights: •Six PAH-degrading microbial consortia were isolated from three oil-contaminated soils. •The bacterial community by 16s rRNA genes was affected by culture media and source soil. •Inoculum should be from the same or similar soil as the soil being bioremediated. -- Bioremediation of oil-contaminated soils was most effective when using inoculum of microbial consortia from the same or similar soil as the soil being bioremediated

  13. Building Learning Communities for Research Collaboration and Cross-Cultural Enrichment in Science Education

    Science.gov (United States)

    Sparrow, E. B.

    2003-12-01

    The GLOBE program has provided opportunities for environmental science research and education collaborations among scientists, teachers and K-12 students, and for cross-cultural enrichment nationally and abroad. In Alaska, GLOBE has also provided funding leverage in some cases, and a base for several other science education programs that share a common goal of increasing student interest, understanding, process skills and achievement in science, through involvement in ongoing research investigations. These programs that use GLOBE methodologies (standardized scientific measurements and learning activities developed by scientists and educators) are: Global Change Education Using Western Science and Native Knowledge also known as "Observing Locally, Connecting Globally" (OLCG); Alaska Earth System Science Education Alliance: Improving Understanding of Climate Variability and Its Relevance to Rural Alaska; Schoolyard Long Term Ecological Research; Alaska Rural Research Partnership; Alaska Partnership for Teacher Enhancement; Alaska Lake Ice and Snow Observatory Network; Alaska Boreal Forest Council Education Outreach; Calypso Farm and Ecology Center; Environmental Education Outreach; and also GLOBE Arctic POPs (persistent organic pollutants) a program that involves countries in the circumpolar North. The University of Alaska GLOBE Partnership has collaborated with the BLM Campbell Creek Science Center Globe Partnership in facilitating GLOBE Training Workshops and providing teacher support. GLOBE's extensive website including data entry, archive, analysis and visualization capabilities; GLOBE Teacher Guide, videos and other materials provided; excellent GLOBE science research and education staff, training support office, GLOBE help desk, alignment of GLOBE curriculum with national science education standards and GLOBE certification of teachers trained on even just one GLOBE investigation, have made it easier to implement GLOBE in the classroom. Using GLOBE, whole classes of students have engaged in and contributed data to science investigations. In Alaska, classes and individual students have conducted their own inquiry studies and have successfully presented their investigations and competed at science fairs and statewide high school science symposium and international conferences. Two students presented their research investigations at the GLOBE Learning Expedition in Croatia and four students presented their study at the GLOBE Arctic POPs Conference in Sweden. These students increased not only their understanding and knowledge of science but also in appreciation of people in other countries and their cultures. Friendships have also bloomed. The learning community in Alaska has expanded to include family and community members including Native elders (using OLCG), teachers, scientists and students from other countries. The following challenges remain: 1) getting funds to be able to provide GLOBE equipment and continuous support to GLOBE teachers and students throughout the year, 2) reaching teachers and students in remote areas, 3) rapid teacher turn-over rate in rural areas, 4) using inquiry-based pedagogies during GLOBE professional development workshops including the opportunity for teacher participants to conduct their own inquiries during the workshop, 5) time, school curriculum and national education requirement constraints, 6) involving school administrators, and more local scientists and community members, and 7) providing culturally relevant and responsive science education programs and life-long learning communities.

  14. Fermentative degradation of nonionic surfactants and polyethylene glycol by enrichment cultures and by pure cultures of homoacetogenic and propionate-forming bacteria.

    OpenAIRE

    WAGENER, Stefan; Schink, Bernhard

    1988-01-01

    Linear alkyl ethoxylates (polyethylene glycol alkyl ethers) were fermented completely to methane and CO2 in enrichment cultures inoculated with anoxic sewage sludge. Long-chain fatty acids were released as intermediates. No degradation was found with polypropylene glycol and polypropylene glycol-containing surfactants. Two types of primary ethoxylate-degrading bacteria were isolated and characterized. Both degraded polyethylene glycols with molecular weights of 1,000 completely. Strain KoB35 ...

  15. Characterization of diverse heterocyclic amine-degrading denitrifying bacteria from various environments.

    Science.gov (United States)

    Bae, Hee-Sung; Im, Wan-Taek; Suwa, Yuichi; Lee, James M; Lee, Sung-Taik; Chang, Young-Keun

    2009-04-01

    Although, there have been many published bacterial strains aerobically degrading the heterocyclic amine compounds, only one strain to date has been reported to degrade pyrrolidine under denitrifying conditions. In this study, denitrifying bacteria degrading pyrrolidine and piperidine were isolated from diverse geological and ecological origins through selective enrichment procedures. Based on the comparative sequence results of 16S rRNA genes, 30 heterocyclic amine-degrading isolates were grouped into ten distinct phylotypes belonging to the genera Thauera, Castellaniella, Rhizobium, or Paracoccus of the phylum Proteobacteria. The representative isolates of individual phylotypes were characterized by phylogenetic, phenotypic and chemotaxonomical traits, and dissimilatory nitrite reductase gene (nirK and nirS). All isolates completely degraded pyrrolidine and piperidine under both aerobic and anaerobic conditions. The anaerobic degradations were coupled to nitrate reduction. A metabolic pathway for the anaerobic degradation of pyrrolidine was proposed on the basis of enzyme activities implicated in pyrrolidine metabolism from three isolates. The three key pyrrolidine-metabolizing enzymes pyrrolidine dehydrogenase, gamma-aminobutyrate/alpha-ketoglutarate aminotransferase, and succinic semialdehyde dehydrogenase, were induced by heterocyclic amines under denitrifying conditions. They were also induced in cells grown aerobically on heterocyclic amines, suggesting that the anaerobic degradation of pyrrolidine shares the pathway with aerobic degradation. PMID:19183960

  16. Addition of novobiocin in pre-enrichment step can improve Salmonella culture protocol of modified semisolid Rappaport-Vassiliadis

    DEFF Research Database (Denmark)

    Jensen, Annette Nygaard; SØrensen, Gitte

    2003-01-01

    The aim was to investigate the effect of addition of Novobiocin to the non-selective buffered peptone water (BPW) for pre-enrichment of Salmonella in connection with plating on modified semisolid Rappaport-Vassiliadis (MSRV). In a semi-quantitative study, the level of Salmonella following pre-enrichment of 32 presumably naturally contaminated swine fecal samples were assessed for BPW with and without addition of Novobiocin (22 mug/ml). In another experiment, a total of 400 swine fecal samples were screened for the presence of Salmonella spp., in order to compare the performance of the nonselective pre-enrichment broth with BPW made semi-selective by addition of Novobiocin. The semi-quantitative assessment of the Salmonella level showed that addition of Novobiocin in the pre-enrichment step on average increased the level of Salmonella 1.2 log dilution steps. When growth was scored at five levels, 90 samples opposed to 50 yielded a strong positive reading (+++) when Novobiocin was applied. Growth was on average0.3 scores higher when pre-enriched with Novobiocin. The difference in growth score medians of the two methods was highly significant (Sign test; p <0.001). Despite the increased sensitivity, 13 culture-positive samples were missed when using the Novobiocin-containing BPW. In conclusion, a simple addition of Novobiocin in the BPW pre-enrichment step of fecal samples may facilitate reading and thereby detection of Salmonella on MSRV. The increase of Salmonella in the semi-quantitative study may be caused by a reduction in the number of competitive microorganisms.

  17. Site-specific variability in BTEX biodegradation under denitrifying conditions

    International Nuclear Information System (INIS)

    Laboratory microcosm experiments were conducted to evaluate the feasibility of benzene, toluene, ethylbenzene, m-xylene, and o-xylene (BTEX) biodegradation under denitrifying conditions. Nine different sources of inocula, including contaminated and uncontaminated soil cores from four different sites and activated sludge, were used to establish microcosms. BTEX was not degraded under denitrifying conditions in microcosms inoculated with aquifer material from Rocky Point and Traverse City. However, rapid depletion of glucose under denitrifying conditions was observed in microcosms containing Rocky Point aquifer material. TEX degradation was observed in microcosms containing Rocky Point aquifer material. TEX degradation was observed in microcosms containing aquifer material from Fort Bragg and Sleeping Bear Dunes and sewage sludge. Benzene was recalcitrant in all microcosms tested. The degradation of o-xylene ceased after toluene, ethylbenzene, and m-xylene were depleted in the Fort Bragg and sludge microcosms, but o-xylene continued to degrade in microcosms with contaminated Sleeping Bear Dunes soil. The most probable number (MPN) of denitrifiers in these nine different inocula were measured using a microtiter technique. There was no correlation between the MPN of denitrifiers and the TEX degradation rate under denitrifying conditions. Experimental results indicate that the degradation sequence and TEX degradation rate under denitrifying conditions may differ among sites. Results also indicate that denitrification alone may not be a suitable bioremediation technology for gasoline-contaminated aquifers because of the inability of denitrifiers to degrade benzene

  18. Enrichment strategy to select functional consortium from mixed cultures: Consortium from rumen liquor for simultaneous cellulose degradation and hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Aijie; Ren, Nanqi [State Key Lab of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); School of Environmental and Municipal Engineering, Harbin Institute of Technology, Harbin 150090 (China); Gao, Lingfang; Xu, Jifei; Liu, Chong; Lee, Duu-Jong [School of Environmental and Municipal Engineering, Harbin Institute of Technology, Harbin 150090 (China)

    2010-12-15

    Strain isolation using conventional roll tube/plating technique is time consuming and is able to culture in vitro only a small fraction of existing microbes in a natural microflora. This paper proposed a simple and rapid method to select the as-simple-as-possible biological consortium by serially diluting the original mixed culture. The diluted which remains, while the one diluted in serial loses the target function, is defined as the functional consortium of the original mixed culture. Since the microbial structure and the reaction pathway incorporated with the functional consortium is much simpler than its original mother liquor, detailed analysis on the strain interaction is possible without the risk of losing key functional strains as often caused from conventional isolation method. The rumen liquor that can degrade cellulose and produce hydrogen is used as a demonstration example. A ''rumen cellulose-degrading bacterial consortium'' (RCBC) was identified using the proposed enrichment strategy. (author)

  19. Differential requirements for enriched atmospheric carbon dioxide content for intracellular growth in cell culture among selected members of the genus Rickettsia.

    OpenAIRE

    Kopmans-Gargantiel, A I; Wisseman, C. L.

    1981-01-01

    In an in vitro chicken embryo cell culture system, strains of Rickettsia prowazekii, R. mooseri, and R. rickettsii, but not of R. tsutsugamushi, required an atmosphere enriched in CO2 for intracellular growth.

  20. Feasibility study of an alkaline-based chemical treatment for the purification of polyhydroxybutyrate produced by a mixed enriched culture.

    Science.gov (United States)

    Jiang, Yang; Mikova, Gizela; Kleerebezem, Robbert; van der Wielen, Luuk Am; Cuellar, Maria C

    2015-12-01

    This study focused on investigating the feasibility of purifying polyhydroxybutyrate (PHB) from mixed culture biomass by alkaline-based chemical treatment. The PHB-containing biomass was enriched on acetate under non-sterile conditions. Alkaline treatment (0.2 M NaOH) together with surfactant SDS (0.2 w/v% SDS) could reach 99% purity, with more than 90% recovery. The lost PHB could be mostly attributed to PHB hydrolysis during the alkaline treatment. PHB hydrolysis could be moderated by increasing the crystallinity of the PHB granules, for example, by biomass pretreatment (e.g. freezing or lyophilization) or by effective cell lysis (e.g. adjusting alkali concentration). The suitability of the purified PHB by alkaline treatment for polymer applications was evaluated by molecular weight and thermal stability. A solvent based purification method was also performed for comparison purposes. As result, PHB produced by mixed enriched cultures was found suitable for thermoplastic applications when purified by the solvent method. While the alkaline method resulted in purity, recovery yield and molecular weight comparable to values reported in literature for PHB produced by pure cultures, it was found unsuitable for thermoplastic applications. Given the potential low cost and favorable environmental impact of this method, it is expected that PHB purified by alkaline method may be suitable for other non-thermal polymer applications, and as a platform chemical. PMID:25642402

  1. An agarose gel-based neurosphere culture system leads to enrichment of neuronal lineage cells in vitro.

    Science.gov (United States)

    Park, Kyuhee; Nam, Yeonju; Choi, Yongmun

    2015-05-01

    Stem cell-based therapy holds great potential especially for neurological disorders. However, clinical applications await further understanding of many aspects of stem cell differentiation and development of technology enabling manipulation of stem cells into desired cell types in the central nervous system. Here, we developed a new method that leads to enrichment of neuronal lineage cells in neural stem cell cultures. The protocol involves cultivation of primary cells derived from the forebrains of rat E18 embryos above a layer of nonadhesive hard agarose gel in the form of neurospheres. In contrast to the neurospheres that were cultured above an anti-adhesive hydrogel layer, the primary cells that were cultured above a layer of agarose gel preferentially differentiated into ?-III tubulin-positive neurons when allowed to undergo differentiation in vitro.In an effort to investigate the mechanism behind this observation, we found that the gene expression of a vertebrate neuronal determination gene (neurogenin1) was enhanced in the neurospheres that proliferated above a layer of agarose gel as compared with the control, and the gene expression level of neurogenin1 was quite well correlated with the rigidity of agarose gel. These results indicate that agarose gel can contribute, at least in part, to enrich neuronal progenitors and immature postmitotic neurons during neurosphere formation and may provide additional information to establish efficient protocols for the neural stem cell-based study. PMID:25539864

  2. Effects of Temperature on Denitrifying Growth and Nitrate Reduction End Products of Comamonas testosteroni Isolated from Estuarine Sediment

    OpenAIRE

    IMAN RUSMANA

    2007-01-01

    Predictions of seasonal changes in N2O emission that occur in natural estuaries are important to anticipate the future implications of global warming. This study showed the effect of temperature on denitrifying growth and nitrate reduction end product of Comamonas testoteroni isolated from estuarine sediment using both batch and continuous cultures. The ?max values of Comamonas testosteroni grown in anaerobic batch culture were increased with increasing temperature, and the highest ?max was f...

  3. Rapid and Specific Detection of Salmonella spp. in Animal Feed Samples by PCR after Culture Enrichment

    OpenAIRE

    Löfström, Charlotta; Knutsson, Rickard; Axelsson, CE; Rådström, Peter

    2004-01-01

    A PCR procedure has been developed for routine analysis of viable Salmonella spp. in feed samples. The objective was to develop a simple PCR-compatible enrichment procedure to enable DNA amplification without any sample pretreatment such as DNA extraction or cell lysis. PCR inhibition by 14 different feed samples and natural background flora was circumvented by the use of the DNA polymerase Tth. This DNA polymerase was found to exhibit a high level of resistance to PCR inhibitors present in t...

  4. Enrichment and identification of ?9-Tetrahydrocannabinolic acid synthase from Pichia pastoris culture supernatants

    Directory of Open Access Journals (Sweden)

    Kerstin Lange

    2015-09-01

    Full Text Available This data article refers to the report ?9-Tetrahydrocannabinolic acid synthase (THCAS production in Pichia pastoris enables chemical synthesis of cannabinoids (Lange et. al. 2015 [2]. THCAS was produced on a 2 L lab scale using recombinant P. pastoris KM71 KE1. Enrichment of THCAS as a technically pure enzyme was realized using dialysis and cationic exchange chromatography. nLC-ESI-MS/MS analysis identified THCAS in different fractions obtained by cationic exchange chromatography.

  5. Microbial succession in response to pollutants in batch-enrichment culture

    Science.gov (United States)

    Jiao, Shuo; Chen, Weimin; Wang, Entao; Wang, Junman; Liu, Zhenshan; Li, Yining; Wei, Gehong

    2016-01-01

    As a global problem, environmental pollution is an important factor to shape the microbial communities. The elucidation of the succession of microbial communities in response to pollutants is essential for developing bioremediation procedures. In the present study, ten batches of soil-enrichment subcultures were subjected to four treatments: phenanthrene, n-octadecane, phenanthrene + n-octadecane, or phenanthrene + n-octadecane + CdCl2. Forty pollutant-degrading consortia, corresponding to each batch of the four treatments were obtained. High-throughput sequencing of the 16S rRNA gene revealed that the diversity, richness and evenness of the consortia decreased throughout the subculturing procedure. The well-known hydrocarbon degraders Acinetobacter, Gordonia, Sphingobium, Sphingopyxis, and Castellaniella and several other genera, including Niabella and Naxibacter, were detected in the enriched consortia. The predominant microbes varied and the microbial community in the consortia gradually changed during the successive subculturing depending on the treatment, indicating that the pollutants influenced the microbial successions. Comparison of the networks in the treatments indicated that organic pollutants and CdCl2 affected the co-occurrence patterns in enriched consortia. In conclusion, single environmental factors, such as the addition of nutrients or selection pressure, can shape microbial communities and partially explain the extensive differences in microbial community structures among diverse environments. PMID:26905741

  6. Macrofaunal Impact on the Denitrifying Bacterial Community in Freshwater Sediment

    DEFF Research Database (Denmark)

    Poulsen, Morten; Stief, Peter

    Sediment-dwelling macroinvertebrates alter their habitat by transporting oxic water into the sediment and enriching it for organic matter, thereby affecting microbial processes in the sediment. Here we report that burrowing macroinvertebrates can also have a pronounced effect on microbial diversity, with nitrate-reducing and denitrifying bacteria as examples. The diversity of these functional groups was compared in sediment microcosms with and without Chironomus plumosus larvae, using the genes encoding nitrate reductase (narG) and nitrous oxide reductase (nosZ) as functional markers. The estimated phylotype richness of narG increased from 68 in sediment without larvae to 170 in sediment with larvae. Part of this increase in narG diversity could be explained by metabolic activation of certain nitrate-reducing bacteria in the gut of C. plumosus, since 18.3 % of the additional phylotypes were found actively expressed in the gut contents of C. plumosus. The remaining increase may be due to the creationof a (on the microscale) more structured habitat by larval activities like burrow construction, bioturbation, and water pumping, possibly combined with a general activation of microbes by enriching the sediment with partly degraded organic material excreted by the larvae. In contrast to narG, nosZ phylotype richness was unaffected by the presence of chironomid larvae, and very few nosZ phylotypes were actively expressed in the larvae gut. Our results suggest that burrowing macroinvertebrates affect the microbial diversity in sediments, both indirectly by their behaviour and directly by activating certain functional groups of microorganisms passing through their gut.

  7. Evaluation of liquid and solid culture media for the recovery and enrichment of Burkholderia cenocepacia from distilled water.

    Science.gov (United States)

    Ahn, Youngbeom; Kim, Jeong Myeong; Ahn, Hyeri; Lee, Yong-Jin; LiPuma, John J; Hussong, David; Cerniglia, Carl E

    2014-07-01

    Burkholderia cepacia complex (BCC) presence has been the cause of recalls of both sterile and non-sterile pharmaceutical products since these opportunistic pathogens have been implicated to cause infections to susceptible individuals. BCC are ubiquitous in nature, but in pharmaceutical settings the most common source is contaminated water systems. Some strains of BCC, previously described as Pseudomonas cepacia, were not readily detected by standard culture methods. We have explored different strategies to recover and enrich Burkholderia cenocepacia previously cultured in distilled water for 40 days. Enrichment media of varied nutrient concentrations and composition were used, including modified Tryptic Soy Agar or Broth (TSA or TSB), Reasoner's 2nd Agar or Broth (R2A or R2AB), Brain-Heart Infusion Broth (BHIB), Mueller-Hinton Broth (MHB), and Ashdown's (ASH) medium. Of the various broth media tested, cell growth was significantly greater in TSB and R2AB than in BHIB, MHB, or ASH broth. TSB and R2AB were also compared for their recovery efficiency. Generally, there was no significant difference between the numbers of B. cenocepacia grown on 15 differently modified TSA and five modified R2A solid media. Overall, however, diluted TSA and TSB media, and R2A and R2AB showed better recovery efficiency than TSA and TSB for inocula containing small numbers of cells. All strains persisted in distilled water for 40 days. Broth media were more effective than solid media for recovery of B. cenocepacia from distilled water. These results may assist in improving detection assays with recovery and enrichment strategies to maximize recovery of these fastidious organisms. PMID:24756630

  8. Cultivation of Mesophilic Soil Crenarchaeotes in Enrichment Cultures from Plant Roots

    OpenAIRE

    Holly M Simon; Jahn, Courtney E.; Bergerud, Luke T.; Marek K. Sliwinski; Weimer, Paul J; Willis, David K.; Goodman, Robert M

    2005-01-01

    Because archaea are generally associated with extreme environments, detection of nonthermophilic members belonging to the archaeal division Crenarchaeota over the last decade was unexpected; they are surprisingly ubiquitous and abundant in nonextreme marine and terrestrial habitats. Metabolic characterization of these nonthermophilic crenarchaeotes has been impeded by their intractability toward isolation and growth in culture. From studies employing a combination of cultivation and molecular...

  9. Enrichment of mixed cultures capable of aerobic degradation of 1,2-dibromoethane.

    OpenAIRE

    Freitas dos Santos, L M; Leak, D.J.; Livingston, A.G.

    1996-01-01

    1,2-dibromoethane (DBE) is a common environmental contaminant; it is potentially carcinogenic and has been detected in soil and groundwater supplies. Most of the biodegradation studies to date have been performed under anaerobic conditions or in the context of soil remediation, where the pollutant concentration was in the parts per billion range. In this work a mixed bacterial culture capable of complete aerobic mineralization of concentrations of DBE up to 1 g liter(-1) under well-controlled...

  10. Stable Nitrogen and Oxygen Isotope Analysis of Nitrate using Denitrifying Bacteria

    Science.gov (United States)

    Edenburn, L.; Michalski, G. M.

    2009-12-01

    The total isotopic composition of nitrate is used for identifying the origin and fate of nitrate in atmospheric, terrestrial and aquatic systems. The analysis of ? 18O, ?15N, and ?17O values each give important and unique information about the sources and sinks of nitrate in these systems. Currently, there is no published method that allows for the simultaneous determination of ?18O, ?15N, and ?17O of nitrate. Cascotti designed a novel method for measurement of ?18O and ?15N in nitrate but not ?17O. This denitrifier method is based on the isotope ratio analysis of nitrous oxide generated by reduction of nitrate by cultured denitrifying bacteria. Kaiser then altered Cascotti's denitrifier method by converting N2O into O2 followed by the quantitative measurement ?18O and ?17O, however ?15N was not measured. Here we present preliminary data on ?15N, ?18O, ?17O values of N2 and O2 generated by the disproportionation of bacterial produced N2O. During the process of denitrification, nitrates are converted to nitrogen gas via a series of intermediate gaseous nitrogen oxide products. This is possible due to the presence of heterotrophic bacteria or autotrophic denitrifiers in select bacteria. Thus, we have chosen three distinct bacteria for the investigation of nitrate reduction for this study: Pseudomonas aureofaciens, Bacillus halodenitrificans, and Achromobacter cycloclastes. They each contain the copper-containing nitrite reductase necessary for the catalyzation of nitrate in order to complete the nitrogen cycle by returning N2 to the atmosphere. Bacillus halodenitrificans has the advantage of being an anaerobic halotolerant (salt-tolerant) denitrifier. Many of our samples have a high saline content; also, pre-concentration techniques using anion resin require elution using high ionic strength solutions. Further, high saline growth solutions limit contamination from other bacteria or organisms. Our efforts also focus on the conversion of N2O over a gold tube into both O2 and N2 using techniques adapted from Cascotti and Kaiser. Our instrument utilizes an extended 11-cup multi-collector feature which does not require a peak jump during analysis on the continuous flow IRMS. Although this is not the first method to study independent measurements of ?18O, ?17O, ?15N, or ?17O, this is first technique that simultaneously detects the stable isotope composition of oxygen and nitrogen in a given nitrate sample. Tests of the impact on isotopic composition by pre-concentration methods have been performed including freeze-drying/evaporation, column chromatography and ion chromatography.

  11. Drinking Water Denitrification using Autotrophic Denitrifying Bacteria in a Fluidized Bed Bioreactor 

    Directory of Open Access Journals (Sweden)

    Abdolmotaleb Seid-mohammadi

    2013-02-01

    Full Text Available Background and Objectives: Contamination of drinking water sources with nitrate may cause adverse effects on human health. Due to operational and maintenance problems of physicochemical nitrate removal processes, using biological denitrification processes have been performed. The aim of this study is to evaluate nitrate removal efficiency from drinking water using autotrophic denitrifying bacteria immobilized on sulfur impregnated activated carbon in a fluidized bed bioreactor. Materials and Methods: After impregnating activated carbon by sulfur as a microorganism carriers and enrichment and inoculation of denitrifying bacteria, a laboratory-scale fluidized bed bioreactor was operated. Nitrate removal efficiency, nitrite, turbidity, hardness and TOC in the effluent were examined during the whole experiment under various conditions including constant influent nitrate concentration as 90 mg NO3--N/l corresponding to different HRT ranging from 5.53 to 1.5 hr. Results: We found that  the denitrification rates was depended on the hydraulic retention time and the nitrate removal efficiency was up to 98%  and nitrite concentration was lower than 1mg/l at optimum HRT=2.4 hr respectively. Moreover, there was no difference in hardness between influent and effluent due to supplying sodium bicarbonate as carbon source for denitrifying bacteria.  However pH, TOC, hardness, and turbidity of the effluent met the W.H.O guidelines for drinking water.  Conclusion: This study demonstrated that an innovative carrier as sulfur impregnated activated carbon could be used as both the biofilm carrier and energy source for treating nitrate contaminated drinking water in the lab-scale fluidized bed bioreactor.

  12. Pilot-scale chitin extraction from shrimp shell waste by deproteination and decalcification with bacterial enrichment cultures.

    Science.gov (United States)

    Bajaj, Mini; Freiberg, Andrea; Winter, Josef; Xu, Youmei; Gallert, Claudia

    2015-11-01

    Extraction of chitin from mechanically pre-purified shrimp shells can be achieved by successive NaOH/HCl treatment, protease/HCl treatment or by environmentally friendly fermentation with proteolytic/lactic acid bacteria (LAB). For the last mentioned alternative, scale-up of shrimp shell chitin purification was investigated in 0.25 L (F1), 10 L (F2), and 300 L (F3) fermenters using an anaerobic, chitinase-deficient, proteolytic enrichment culture from ground meat for deproteination and a mixed culture of LAB from bio-yoghurt for decalcification. Protein removal in F1, F2, and F3 proceeded in parallel within 40 h at an efficiency of 89-91 %. Between 85 and 90 % of the calcit was removed from the shells by LAB in another 40 h in F1, F2, and F3. After deproteination of shrimp shells in F3, spent fermentation liquor was re-used for a next batch of 30-kg shrimp shells in F4 (300 L) which eliminated 85.5 % protein. The purity of the resulting chitin was comparable in F1, F2, F3, and F4. Viscosities of chitosan, obtained after chitin deacetylation and of chitin, prepared biologically or chemically in the laboratory, were much higher than those of commercially available chitin and chitosan. PMID:26227412

  13. Distribution of Microorganisms in Deep-Sea Hydrothermal Vent Chimneys Investigated by Whole-Cell Hybridization and Enrichment Culture of Thermophilic Subpopulations

    OpenAIRE

    Harmsen, H.; Prieur, D; Jeanthon, C.

    1997-01-01

    The microbial community structure of hydrothermal vent chimneys was evaluated by the combined use of enrichment cultures and whole-cell hybridizations with fluorescently labeled 16S rRNA-based oligonucleotide probes. Chimneys were collected during the Microsmoke cruise on the Mid-Atlantic Ridge and were subsampled on board and stored under reduced conditions or fixed. For estimation of culturable thermophiles, selective media were inoculated by dilution series of the samples and incubated at ...

  14. Proteins differentially expressed in human beta-cells-enriched pancreatic islet cultures and human insulinomas

    DEFF Research Database (Denmark)

    Terra, Letícia F; Teixeira, Priscila C

    2013-01-01

    In view of the great demand for human beta-cells for physiological and medical studies, we generated cell lines derived from human insulinomas which secrete insulin, C-peptide and express neuroendocrine and islet markers. In this study, we set out to characterize their proteomes, comparing them to those of primary beta-cells using DIGE followed by MS. The results were validated by Western blotting. An average of 1800 spots was detected with less than 1% exhibiting differential abundance. Proteins more abundant in human islets, such as Caldesmon, are involved in the regulation of cell contractility, adhesion dependent signaling, and cytoskeletal organization. In contrast, almost all proteins more abundant in insulinoma cells, such as MAGE2, were first described here and could be related to cell survival and resistance to chemotherapy. Our proteomic data provides, for the first time, a molecular snapshot of the orchestrated changes in expression of proteins involved in key processes which could be correlated with the altered phenotype of human beta-cells. Collectively our observations prompt research towards the establishment of bioengineered human beta-cells providing a new and needed source of cultured human beta-cells for beta-cell research, along with the development of new therapeutic strategies for detection, characterization and treatment of insulinomas.

  15. Accumulation of nitrite in denitrifying barriers when phosphate is limiting

    Science.gov (United States)

    Hunter, W. J.

    2003-10-01

    Permeable in situ denitrifying barriers can remove nitrate from groundwater. Barriers may be constructed by filling an excavated area with a porous mixture of sand, fine gravel, and substrate or by the injection of a nonaqueous phase substrate into an aquifer. The substrate stimulates the development of a denitrifying microbial community by providing an electron donor. The objective of this study was to determine the ability of denitrifying barriers to function under low-phosphate conditions. Sand columns injected with a soybean oil emulsion were used as laboratory models of denitrifying barriers. When a natural groundwater containing 17 mg l -1 nitrate-N and 0.009 mg l -1 phosphate-P was pumped through the columns, only a small amount of nitrate was removed from the water and, in some effluent fractions, 52% to 88% of the influent nitrate had converted to nitrite. Nitrite also accumulated when the phosphate concentration of the groundwater was increased to 0.040 or 0.080 mg l -1 phosphate-P. Only when a 0.160 mg l -1 phosphate-P supplement was added to the groundwater was there a loss of nitrate without a large accumulation of nitrite. The addition of solid calcium phosphate or rock phosphate to the sand columns was found to provide adequate phosphate for denitrification in short-term studies. These studies point out the need to ensure that adequate phosphate is present in denitrifying barriers especially when such barriers are used beneath phosphate-binding soils.

  16. Denitrifying capability and community dynamics of glycogen accumulating organisms during sludge granulation in an anaerobic-aerobic sequencing batch reactor

    Science.gov (United States)

    Bin, Zhang; Bin, Xue; Zhigang, Qiu; Zhiqiang, Chen; Junwen, Li; Taishi, Gong; Wenci, Zou; Jingfeng, Wang

    2015-08-01

    Denitrifying capability of glycogen accumulating organisms (GAOs) has received great attention in environmental science and microbial ecology. Combining this ability with granule processes would be an interesting attempt. Here, a laboratory-scale sequencing batch reactor (SBR) was operated to enrich GAOs and enable sludge granulation. The results showed that the GAO granules were cultivated successfully and the granules had denitrifying capability. The batch experiments demonstrated that all NO3--N could be removed or reduced, some amount of NO2--N were accumulated in the reactor, and N2 was the main gaseous product. SEM analysis suggested that the granules were tightly packed with a large amount of tetrad-forming organisms (TFOs); filamentous bacteria served as the supporting structures for the granules. The microbial community structure of GAO granules was differed substantially from the inoculant conventional activated sludge. Most of the bacteria in the seed sludge grouped with members of Proteobacterium. FISH analysis confirmed that GAOs were the predominant members in the granules and were distributed evenly throughout the granular space. In contrast, PAOs were severely inhibited. Overall, cultivation of the GAO granules and utilizing their denitrifying capability can provide us with a new approach of nitrogen removal and saving more energy.

  17. Characterization of bacterial diversity in an atrazine degrading enrichment culture and degradation of atrazine, cyanuric acid and biuret in industrial wastewater.

    Science.gov (United States)

    Dutta, Anirban; Vasudevan, Venugopal; Nain, Lata; Singh, Neera

    2016-01-01

    An enrichment culture was used to study atrazine degradation in mineral salt medium (MSM) (T1), MSM+soil extract (1:1, v/v) (T2) and soil extract (T3). Results suggested that enrichment culture required soil extract to degrade atrazine, as after second sequential transfer only partial atrazine degradation was observed in T1 treatment while atrazine was completely degraded in T2 and T3 treatments even after fourth transfer. Culture independent polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) technique confirmed selective enrichment of genus Bacillus along with Pseudomonas and Burkholderia. Degradation of atrazine/metabolites in the industrial wastewater was studied at different initial concentrations of the contaminants [wastewater-water (v/v) ratio: T1, 1:9; T2, 2:8; T3, 3:7; T4, 5:5 and T5, undiluted effluent]. The initial concentrations of atrazine, cyanuric acid and biuret ranged between 5.32 and 53.92 µg mL(-1), 265.6 and 1805.2 µg mL(-1) and 1.85 and 16.12 µg mL(-1), respectively. The enrichment culture was able to completely degrade atrazine, cyanuric acid and biuret up to T4 treatment, while no appreciable degradation of contaminants was observed in the undiluted effluent (T5). Inability of enrichment culture to degrade atrazine/metabolites might be due to high concentrations of cyanuric acid. Therefore, a separate study on cyanuric acid degradation suggested: (i) no appreciable cyanuric acid degradation with accumulation of an unidentified metabolite in the medium where cyanuric acid was supplemented as the sole source of carbon and nitrogen; (ii) partial cyanuric acid degradation with accumulation of unidentified metabolite in the medium containing additional nitrogen source; and (iii) complete cyanuric acid degradation in the medium supplemented with an additional carbon source. This unidentified metabolite observed during cyanuric acid degradation and also detected in the enrichment culture inoculated wastewater samples, however, was degraded up to T4 treatments and was persistent in the T5 treatment. Probably, accumulation of this metabolite inhibited atrazine/cyanuric acid degradation by the enrichment culture in undiluted wastewater. PMID:26479154

  18. Inhibitory Effect of Gamma-Irradiated Chitosan on the Growth of Denitrifiers

    Directory of Open Access Journals (Sweden)

    Javier Vilcáez

    2009-01-01

    Full Text Available In order to find an environmentally benign substitute to hazardous inhibitory agents, the inhibitory effect of ?-irradiated chitosans against a mixed culture of denitrifying bacteria was experimentally evaluated. Unlike other studies using pure aerobic cultures, the observed effect was not a complete inhibition but a transient inhibition reflected by prolonged lag phases and reduced growth rates. Raw chitosan under acid conditions (pH 6.3 exerted the strongest inhibition followed by the 100?kGy and 500?kGy irradiated chitosans, respectively. Therefore, because the molecular weight of chitosan decreases with the degree of ?-irradiation, the inhibitory properties of chitosan due to its high molecular weight were more relevant than the inhibitory properties gained due to the modification of the surface charge and/or chemical structure by ?-irradiation. High dosage of ?-irradiated appeared to increase the growth of mixed denitrifying bacteria in acid pH media. However, in neutral pH media, high dosage of ?-irradiation appeared to enhance the inhibitory effect of chitosan.

  19. Diversity and activity of denitrifiers of Chilean arid soil ecosystems

    Directory of Open Access Journals (Sweden)

    GescheBraker

    2012-04-01

    Full Text Available The Chilean sclerophyllous matorral is a Mediterranean semiarid ecosystem affected by erosion, with low soil fertility and limited by nitrogen. However, limitation of resources is even more severe for desert soils such as from the Atacama Desert, one of the most extreme arid deserts on Earth. Topsoil organic matter, nitrogen and moisture content were significantly higher in the semiarid soil compared to the desert soil. Although the most significant loss of biologically preferred nitrogen from terrestrial ecosystems occurs via denitrification, virtually nothing is known on the activity and composition of denitrifier communities thriving in arid soils. In this study, we explored denitrifier communities from two soils with profoundly distinct edaphic factors. While denitrification activity in the desert soil was below detection limit, the semiarid soil sustained denitrification activity. To elucidate the genetic potential of the soils to sustain denitrification processes we performed community analysis of denitrifiers based on nitrite reductase (nirK and nirS genes as functional marker genes for this physiological group. Presence of nirK-type denitrifiers in both soils was demonstrated but failure to amplify nirS from the desert soil suggests very low abundance of nirS-type denitrifiers shedding light on the lack of denitrification activity. Phylogenetic analysis showed a very low diversity of nirK with only three distinct genotypes in the desert soil which conditions presumably exert a high selection pressure. While nirK diversity was also limited to only few, albeit distinct genotypes, the semiarid matorral soil showed a surprisingly broad genetic variability of the nirS gene. The Chilean matorral is a shrub land plant community which form vegetational patches stabilizing the soil and increasing its nitrogen and carbon content. These islands of fertility may sustain the development and activity of the overall microbial community and of denitrifiers in particular.

  20. Cultivation and irradiation of human fibroblasts in a medium enriched with platelet lysate for obtaining feeder layer in epidermal cell culture

    International Nuclear Information System (INIS)

    For over 30 years, the use of culture medium, enriched with bovine serum, and murines fibroblasts, with the rate of proliferation controlled by irradiation or by share anticarcinogenic drugs, has been playing successfully its role in assisting in the development of keratinocytes in culture, for clinical purposes. However, currently there is a growing concern about the possibility of transmitting prions and animals viruses to transplanted patients. Taking into account this concern, the present work aims to cultivate human fibroblasts in a medium enriched with human platelets lysate and determine the irradiation dose of these cells, for obtaining feeder layer in epidermal cell culture. For carrying out the proposed objective, platelets lysis has standardized, this lysate was used for human fibroblasts cultivation and the irradiation dose enough to inhibit its duplication was evaluated. Human keratinocytes were cultivated in these feeder layers, in culture medium enriched with the lysate. With these results we conclude that the 10% platelets lysate promoted a better adhesion and proliferation of human fibroblasts and in all dose levels tested (60 to 300 Gy), these had their mitotic activity inactivated by ionizing irradiation, being that the feeder layers obtained with doses from 70 to 150 Gy were those that provided the best development of keratinocytes in medium containing 2.5% of human platelet lysate. Therefore, it was possible to standardize both the cultivation of human fibroblasts as its inactivation for use as feeder layer in culture of keratinocytes, so as to eliminate xenobiotics components. (author)

  1. Rate of denitrification and the accumulation of intermediates in a denitrifying bioreactor

    Science.gov (United States)

    Parsignault, D. R.; Gursky, H.; Kellogg, E. M.; Matilsky, T.; Murray, S.; Schreier, E.; Tananbaum, H.; Giacconi, R.; Brinkman, A. C.

    2012-12-01

    Denitrifying bioreactors (DNBRs) are an emerging mechanism to mitigate the impact of excess reactive nitrogen by harnessing the activity of ubiquitous denitrifying soil microbes. DNBRs fundamentally consist of an organic carbon energy source sufficiently saturated to develop anaerobic conditions and support heterotrophic reduction of nitrate to dinitrogen. Although recent research has well established achievable nitrate removal in DNBRs upwards of 90%, few studies experimentally determine the fate of nitrogen in these systems. This study differentiates between denitrification to inert nitrogen gas, which permanently removes reactive nitrogen from an enriched ecosystem, and transformation of nitrate to another bioavailable form (such as N2O or NOX, powerful greenhouse gases). Previous research has failed to make this distinction and as both are perceived as a reduction in nitrate concentration at the outlet, the utility of DNBRs in reducing downstream reactive nitrogen has not been sufficiently established. In order to quantify the rate of nitrate removal and the products produced, dissolved gas samples are collected from the DNBR with passive diffusion gas samplers while the influent and effluent nitrate concentration and chemical oxygen demand are monitored in real time with spectrometer probes. Nitrate removal is compared with the denitrification rate and the ratio of dinitrogen to nitrous oxide is reported. Denitrification is quantified from the proportion of nitrogen gas products produced from the nitrate pool, indicated by the negative congruence of the regression of 15N enrichment in the nitrate pool and temporal depletion in the gaseous products. The proportion of nitrous oxide to dinitrogen is examined with respect to saturation and redox potential. This research informs the interpretation of previous studies as well as advises the focus of long-term system level monitoring that will provide further information on the design and application of DNBRs to mitigate nitrate pollution.

  2. Hydraulic flow characteristics of agricultural residues for denitrifying bioreactor media

    Science.gov (United States)

    Denitrifying bioreactors are a promising technology to mitigate agricultural subsurface drainage nitrate-nitrogen losses, a critical water quality goal for the Upper Mississippi River Basin. This study was conducted to evaluate the hydraulic properties of agricultural residues that are potential bio...

  3. Higher diversity and abundance of denitrifying microorganisms in environments than considered previously.

    Science.gov (United States)

    Wei, Wei; Isobe, Kazuo; Nishizawa, Tomoyasu; Zhu, Lin; Shiratori, Yutaka; Ohte, Nobuhito; Koba, Keisuke; Otsuka, Shigeto; Senoo, Keishi

    2015-09-01

    Denitrification is an important process in the global nitrogen cycle. The genes encoding NirK and NirS (nirK and nirS), which catalyze the reduction of nitrite to nitric oxide, have been used as marker genes to study the ecological behavior of denitrifiers in environments. However, conventional polymerase chain reaction (PCR) primers can only detect a limited range of the phylogenetically diverse nirK and nirS. Thus, we developed new PCR primers covering the diverse nirK and nirS. Clone library and qPCR analysis using the primers showed that nirK and nirS in terrestrial environments are more phylogenetically diverse and 2-6 times more abundant than those revealed with the conventional primers. RNA- and culture-based analyses using a cropland soil also suggested that microorganisms with previously unconsidered nirK or nirS are responsible for denitrification in the soil. PCR techniques still have a greater capacity for the deep analysis of target genes than PCR-independent methods including metagenome analysis, although efforts are needed to minimize the PCR biases. The methodology and the insights obtained here should allow us to achieve a more precise understanding of the ecological behavior of denitrifiers and facilitate more precise estimate of denitrification in environments. PMID:25756678

  4. Isotope effects and O-exchange with water during N2O production by denitrifying fungi

    Science.gov (United States)

    Rohe, Lena; Braker, Gesche; Well, Reinhard; Giesemann, Anette; Anderson, Traute-Heidi; Wrage-Mönnig, Nicole; Flessa, Heinz

    2013-04-01

    N2O from soil denitrification originates from bacteria and - to an unknown extent - also from fungi. In pure culture studies, bacterial and fungal denitrification showed differences in isotopomer ratios of N2O. Isotopomer ratios of N2O can be expressed as 15N site preference (SP), i.e. the difference between ?15N of the central and terminal N-position of the asymmetric N2O molecule and might be suitable to distinguish between bacterial and fungal N2O under denitrifying soil conditions. Oxygen exchange takes place between H2O and intermediates during the denitrification process. Several studies showed that O-exchange of bacterial denitrifiers varies, but information about fungal O-exchanges is lacking. The objectives of the study presented are i) to verify SP of fungal N2O reported for two strains from pure culture studies and ii) to analyze the oxygen exchange between intermediates and H2O during denitrification in fungal pure cultures. Six different fungal pure cultures known to be capable of denitrification were incubated under anaerobic conditions, either with nitrite or nitrate. Gas samples were analysed for concentration and isotopic signatures (SP, average ?15N, ?18O) of N2O. To investigate the oxygen exchange, both treatments were also established in a tracer experiment where 18O-labelled water was used in the medium. The fungal strains evaluated so far indicate similar SP as reported previously. Concerning the amount of N2O produced, the nitrite led to a higher yield than nitrate. O-exchange with 18O-labelled water during fungal denitrification was visible. Using nitrite, the exchange ranged amounted from 39% to full exchange while nitrate led to exchange rates between 13% and full exchange. Detailed results will be presented.

  5. Preparation of glycerol-enriched yeast culture and its effect on blood metabolites and ruminal fermentation in goats.

    Science.gov (United States)

    Ye, Gengping; Zhu, Yongxing; Liu, Jin; Chen, Xingxiang; Huang, Kehe

    2014-01-01

    The aim of this study was to isolate a glycerol-producing yeast strain from nature to prepare glycerol-enriched yeast culture (GY), and preliminarily evaluate the effects of GY on blood metabolites and ruminal fermentation in goats. During the trial, six isolates were isolated from unprocessed honey, and only two isolates with higher glycerol yield were identified by analysis of 26S ribosomal DNA sequences. One of the two isolates was identified as Saccharomyces cerevisiae, a direct-fed microbe permitted by the FDA. This isolate was used to prepare GY. The fermentation parameters were optimized through single-factor and orthogonal design methods to maximize the glycerol yield and biomass. The final GY contained 38.7±0.6 g/L glycerol and 12.6±0.5 g/L biomass. In vivo, eight castrated male goats with ruminal fistula were used in a replicated 4×4 Latin square experiment with four consecutive periods of 15 d. Treatments were as follows: control, LGY, MGY, and HGY with 0, 100, 200, and 300 mL GY per goat per day, respectively. The GY was added in two equal portions at 08?00 and 17?00 through ruminal fistula. Samples of blood and ruminal fluid were collected on the last one and two days of each period, respectively. Results showed that the plasma concentrations of triglyceride and total cholesterol were not affected by the supplemented GY. Compared with the control, goats supplemented with MGY and HGY had significantly higher (Pglucose and total protein, ruminal volatile fatty acid and molar proportion of propionate, and significantly lower (Peffects of glycerol and yeast for ruminants. PMID:24709881

  6. Comparative metagenomics of three Dehalococcoides-containing enrichment cultures: the role of the non-dechlorinating community

    Directory of Open Access Journals (Sweden)

    Hug Laura A

    2012-07-01

    Full Text Available Abstract Background The Dehalococcoides are strictly anaerobic bacteria that gain metabolic energy via the oxidation of H2 coupled to the reduction of halogenated organic compounds. Dehalococcoides spp. grow best in mixed microbial consortia, relying on non-dechlorinating members to provide essential nutrients and maintain anaerobic conditions. A metagenome sequence was generated for the dechlorinating mixed microbial consortium KB-1. A comparative metagenomic study utilizing two additional metagenome sequences for Dehalococcoides-containing dechlorinating microbial consortia was undertaken to identify common features that are provided by the non-dechlorinating community and are potentially essential to Dehalococcoides growth. Results The KB-1 metagenome contained eighteen novel homologs to reductive dehalogenase genes. The metagenomes obtained from the three consortia were automatically annotated using the MG-RAST server, from which statistically significant differences in community composition and metabolic profiles were determined. Examination of specific metabolic pathways, including corrinoid synthesis, methionine synthesis, oxygen scavenging, and electron-donor metabolism identified the Firmicutes, methanogenic Archaea, and the ?-Proteobacteria as key organisms encoding these pathways, and thus potentially producing metabolites required for Dehalococcoides growth. Conclusions Comparative metagenomics of the three Dehalococcoides-containing consortia identified that similarities across the three consortia are more apparent at the functional level than at the taxonomic level, indicating the non-dechlorinating organisms’ identities can vary provided they fill the same niche within a consortium. Functional redundancy was identified in each metabolic pathway of interest, with key processes encoded by multiple taxonomic groups. This redundancy likely contributes to the robust growth and dechlorination rates in dechlorinating enrichment cultures.

  7. Trace Gas Emission from in-Situ Denitrifying Bioreactors

    Science.gov (United States)

    Pluer, W.; Walter, M. T.; Geohring, L.

    2014-12-01

    Despite decades of concerted effort to mitigate nonpoint source nitrate (NO3-) pollution from agricultural lands, these efforts have not been sufficient to arrest eutrophication. A primary process for removing excess NO3- from water is denitrification, where denitrifying bacteria use NO3- for respiration in the absence of oxygen. Denitrification results in reduced forms of nitrogen, often dinitrogen gas (N2) but also nitrous oxide (N2O), an aggressive greenhouse gas. A promising solution to NO3- pollution is to intercept agricultural discharges with denitrifying bioreactors (DNBRs). DNBRs provide conditions ideal for denitrifiers: an anaerobic environment, sufficient organic matter, and excess NO3-. These conditions are also ideal for methanogens, which produce methane (CH4), another harmful trace gas. While initial results from bioreactor studies show that they can cost-effectively remove NO3-, trace gas emissions are an unintended consequence. This study's goal was to determine how bioreactor design promotes denitrification while limiting trace gas production. Reactor inflow and outflow water samples were tested for nutrients, including NO3-, and dissolved inflow and outflow gas samples were tested for N2O and CH4. NO3- reduction and trace gas production were evaluated at various residence times, pHs, and inflow NO3- concentrations in field and lab-scale reactors. Low NO3- reduction indicated conditions that stressed denitrifying bacteria while high reductions indicated designs that optimized pollutant treatment for water quality. Several factors influenced high N2O, suggesting non-ideal conditions for the final step of complete denitrification. High CH4 emissions pointed to reactor media choice for discouraging methanogens, which may remove competition with denitrifiers. It is critical to understand all of potential impacts that DNBRs may have, which means identifying processes and design specifications that may affect them.

  8. Distribution of Microorganisms in Deep-Sea Hydrothermal Vent Chimneys Investigated by Whole-Cell Hybridization and Enrichment Culture of Thermophilic Subpopulations

    Science.gov (United States)

    Harmsen, H.; Prieur, D.; Jeanthon, C.

    1997-01-01

    The microbial community structure of hydrothermal vent chimneys was evaluated by the combined use of enrichment cultures and whole-cell hybridizations with fluorescently labeled 16S rRNA-based oligonucleotide probes. Chimneys were collected during the Microsmoke cruise on the Mid-Atlantic Ridge and were subsampled on board and stored under reduced conditions or fixed. For estimation of culturable thermophiles, selective media were inoculated by dilution series of the samples and incubated at 65, 80, and 95(deg)C. To analyze the microbial diversity of the samples, cells were extracted from the fixed chimney structure samples and hybridized with domain- and kingdom-specific probes. Quantification of the extracted cells was assessed by whole-cell hybridization on membrane filters. By both methods, the largest amounts of microorganisms were found in the upper and outer parts of the chimneys, although even the inner parts contained culturable and detectable amounts of cells. Different morphotypes of thermophilic and hyperthermophilic microorganisms were enriched and detected in samples. Our data clearly indicate that the morphological diversity observed by using whole-cell hybridization is much larger than that assessed by use of culture-based enrichments. This new approach, including culture-independent and -dependent methods to study hydrothermal vent chimneys, showed an uneven distribution of a diverse microbial community. Application of lower-level specific probes for known families and genera within each domain by our approach will be useful to reveal the real extent and nature of the chimney microbial diversity and to support cultivation attempts. PMID:16535655

  9. Enhanced nitrate and phosphate removal in a denitrifying bioreactor with biochar.

    Science.gov (United States)

    Bock, Emily; Smith, Nick; Rogers, Mark; Coleman, Brady; Reiter, Mark; Benham, Brian; Easton, Zachary M

    2015-03-01

    Denitrifying bioreactors (DNBRs) are an emerging technology used to remove nitrate-nitrogen (NO) from enriched waters by supporting denitrifying microorganisms with organic carbon in an anaerobic environment. Field-scale investigations have established successful removal of NO from agricultural drainage, but the potential for DNBRs to remediate excess phosphorus (P) exported from agricultural systems has not been addressed. We hypothesized that biochar addition to traditional woodchip DNBRs would enhance NO and P removal and reduce nitrous oxide (NO) emissions based on previous research demonstrating reduced leaching of NO and P and lower greenhouse gas production associated with biochar amendment of agricultural soils. Nine laboratory-scale DNBRs, a woodchip control, and eight different woodchip-biochar treatments were used to test the effect of biochar on nutrient removal. The biochar treatments constituted a full factorial design of three factors (biochar source material [feedstock], particle size, and application rate), each with two levels. Statistical analysis by repeated measures ANOVA showed a significant effect of biochar, time, and their interaction on NO and dissolved P removal. Average P removal of 65% was observed in the biochar treatments by 18 h, after which the concentrations remained stable, compared with an 8% increase in the control after 72 h. Biochar addition resulted in average NO removal of 86% after 18 h and 97% after 72 h, compared with only 13% at 18 h and 75% at 72 h in the control. Biochar addition also resulted in significantly lower NO production. These results suggest that biochar can reduce the design residence time by enhancing nutrient removal rates. PMID:26023979

  10. 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.

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

    International Nuclear Information System (INIS)

    Highlights: â–º We started up microbial fuel cell (MFC) using enriched sulfate-reducing mixed culture. â–º Sulfate-reducing bacteria and anode-respiring bacteria were enriched in anodic biofilms. â–º The MFC effectively remove sulfate to elementary sulfur in the presence of lactate. â–º 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.

  12. N-acyl homoserine lactone-degrading microbial enrichment cultures isolated from Penaeus vannamei shrimp gut and their probiotic properties in Brachionus plicatilis cultures

    OpenAIRE

    Tinh, N.T.N.; Asanka Gunasekara, R.A.Y.S.; Boon, N.; Dierckens, K.; Sorgeloos, P.; Bossier, P

    2007-01-01

    Three bacterial enrichment cultures (ECs) were isolated from the digestive tract of Pacific white shrimp Penaeus vannamei, by growing the shrimp microbial communities in a mixture of N-acyl homoserine lactone (AHL) molecules. The ECs, characterized by denaturing gradient gel electrophoresis analysis and subsequent rRNA sequencing, degraded AHL molecules in the degradation assays. Apparently, the resting cells of the ECs also degraded one of the three types of quorum-sensing signal molecules p...

  13. Clustering and nonlinear regression analysis applied to the in vitro growing of Leucoagaricus gongylophorus (Singer Möller in a culture environment enriched with different botanical extracts

    Directory of Open Access Journals (Sweden)

    Marcelo Dias de Souza

    2011-12-01

    Full Text Available The study aimed to evaluate the in vitro growing of Leucoagaricus gongylophorus in a culture environment enriched with different extracts from botanical species, via multivariate statistical analysis of data clustering, besides identifying the fungus behavior through nonlinear regression equations. The fungus was inoculated into a BDA medium enriched with eight botanical extracts, along with two controls (with and without the addition of 20mL distilled water, in Petri plates. The plates were kept in a climatized chamber at a 25±1ºC temperature in the dark, during a 42 days period and the fungus growing was evaluated at weekly intervals. It was proved that the clustering analysis and the Chapman-Richards model are effi cient to verify the similarity of different botanical extracts in the fungus development, as well as to estimate and describe the growing of L. gongylophorus.

  14. Isolation and Molecular Identification of an Aerobic Denitrifier

    Directory of Open Access Journals (Sweden)

    Hongyu Wang

    2013-10-01

    Full Text Available Six bacteria strains of which total nitrogen removal efficiency is over 70% were isolated from the activated sludge after enrichment culture. The strain Z31 with higher nitrogen removal was selected and its characteristic of aerobic denitrification was confirmed by the nitrogen element track. The results showed that the nitrate in the culture could be efficiently removed by strain Z31 and the nitrate nitrogen removal rate was up to above 95%. There was obvious nitrite accumulation during the denitrification process. Moreover, medium pH was increased and medium ORP was decreased as a result of denitrification. According to the morphological observation, physiological biochemical test and sequence analysis of the 16S rDNA, strain Z31 was identified as Pseudomonas stutzeri. And the phylogentic position of the strain was performed based on the phylogenetic tree.

  15. Warming-induced changes in denitrifier community structure modulate the ability of phototrophic river biofilms to denitrify

    International Nuclear Information System (INIS)

    Microbial denitrification is the main nitrogen removing process in freshwater ecosystems. The aim of this study was to show whether and how water warming (+ 2.5 °C) drives bacterial diversity and structuring and how bacterial diversity affects denitrification enzymatic activity in phototrophic river biofilms (PRB). We used water warming associated to the immediate thermal release of a nuclear power plant cooling circuit to produce natural PRB assemblages on glass slides while testing 2 temperatures (mean temperature of 17 °C versus 19.5 °C). PRB were sampled at 2 sampling times during PRB accretion (6 and 21 days) in both temperatures. Bacterial community composition was assessed using ARISA. Denitrifier community abundance and denitrification gene mRNA levels were estimated by q-PCR and qRT-PCR, respectively, of 5 genes encoding catalytic subunits of the denitrification key enzymes. Denitrification enzyme activity (DEA) was measured by the acetylene-block assay at 20 °C. A mean water warming of 2.5 °C was sufficient to produce contrasted total bacterial and denitrifier communities and, therefore, to affect DEA. Indirect temperature effect on DEA may have varied between sampling time, increasing by up to 10 the denitrification rate of 6-day-old PRB and decreasing by up to 5 the denitrification rate of 21-day-old PRB. The present results suggest that indirect effects of warming through changes in bacterial community composition, coupled to the strong direct effect of temperature on DEA already demonstrated in PRB, could modulate dissolved nitrogen removal by denitrification in rivers and streams. - Highlights: •We produced river biofilms in 2 mean temperature conditions: 17 vs 19.5 °C. •We compared their denitrifiers' structuring and functioning in 6d- and 21d-old biofilms. •A difference of 2.5 °C produced contrasted denitrifier communities. •The indirect temperature effect on denitrification activity shifted between biofilm age. •Warming impact strongly depends on the bacterial successional trajectory

  16. Warming-induced changes in denitrifier community structure modulate the ability of phototrophic river biofilms to denitrify

    Energy Technology Data Exchange (ETDEWEB)

    Boulêtreau, Stéphanie, E-mail: stephanie.bouletreau@univ-tlse3.fr [Université de Toulouse, UPS, INP, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), 118 route de Narbonne, F-31062 Toulouse (France); CNRS, EcoLab, F-31062 Toulouse (France); Lyautey, Emilie [Université de Toulouse, UPS, INP, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), 118 route de Narbonne, F-31062 Toulouse (France); CNRS, EcoLab, F-31062 Toulouse (France); Dubois, Sophie [Université de Bordeaux, EPOC - OASU, UMR 5805, Station Marine d' Arcachon, 2 rue du Professeur Jolyet, 33120 Arcachon (France); Compin, Arthur [Université de Toulouse, UPS, INP, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), 118 route de Narbonne, F-31062 Toulouse (France); CNRS, EcoLab, F-31062 Toulouse (France); Delattre, Cécile; Touron-Bodilis, Aurélie [EDF Recherche et Développement, LNHE (Laboratoire National d' Hydraulique et Environnement), 6 quai Watier, F-78401 Chatou (France); Mastrorillo, Sylvain [Université de Toulouse, UPS, INP, EcoLab (Laboratoire Ecologie Fonctionnelle et Environnement), 118 route de Narbonne, F-31062 Toulouse (France); CNRS, EcoLab, F-31062 Toulouse (France); Garabetian, Frédéric [Université de Bordeaux, EPOC - OASU, UMR 5805, Station Marine d' Arcachon, 2 rue du Professeur Jolyet, 33120 Arcachon (France)

    2014-01-01

    Microbial denitrification is the main nitrogen removing process in freshwater ecosystems. The aim of this study was to show whether and how water warming (+ 2.5 °C) drives bacterial diversity and structuring and how bacterial diversity affects denitrification enzymatic activity in phototrophic river biofilms (PRB). We used water warming associated to the immediate thermal release of a nuclear power plant cooling circuit to produce natural PRB assemblages on glass slides while testing 2 temperatures (mean temperature of 17 °C versus 19.5 °C). PRB were sampled at 2 sampling times during PRB accretion (6 and 21 days) in both temperatures. Bacterial community composition was assessed using ARISA. Denitrifier community abundance and denitrification gene mRNA levels were estimated by q-PCR and qRT-PCR, respectively, of 5 genes encoding catalytic subunits of the denitrification key enzymes. Denitrification enzyme activity (DEA) was measured by the acetylene-block assay at 20 °C. A mean water warming of 2.5 °C was sufficient to produce contrasted total bacterial and denitrifier communities and, therefore, to affect DEA. Indirect temperature effect on DEA may have varied between sampling time, increasing by up to 10 the denitrification rate of 6-day-old PRB and decreasing by up to 5 the denitrification rate of 21-day-old PRB. The present results suggest that indirect effects of warming through changes in bacterial community composition, coupled to the strong direct effect of temperature on DEA already demonstrated in PRB, could modulate dissolved nitrogen removal by denitrification in rivers and streams. - Highlights: •We produced river biofilms in 2 mean temperature conditions: 17 vs 19.5 °C. •We compared their denitrifiers' structuring and functioning in 6d- and 21d-old biofilms. •A difference of 2.5 °C produced contrasted denitrifier communities. •The indirect temperature effect on denitrification activity shifted between biofilm age. •Warming impact strongly depends on the bacterial successional trajectory.

  17. Cr(VI) reduction under aerobic and denitrifying conditions by an aquifer-derived Pseudomonad

    Science.gov (United States)

    Beller, H. R.; Han, R.; Geller, J. T.

    2009-12-01

    Chromium contamination of groundwater is widespread within the Department of Energy (DOE) complex. For example, at DOE’s Hanford 100 Area in Washington state, the volume of Cr-contaminated groundwater is estimated to be 1.5 billion gallons. Bioremediation (in situ reductive immobilization) studies involving injection of a lactate-containing polymer have been conducted in the Hanford 100H area, where we have observed sequential use of the dissolved electron acceptors present in groundwater, namely, oxygen, nitrate, and sulfate. As part of an effort to explore Cr(VI) reduction under relevant electron-accepting conditions and with relevant bacteria, we have conducted studies with strain RCH2, a denitrifying bacterium similar to Pseudomonas stutzeri that was isolated from the Hanford 100H aquifer. Cell suspension studies with lactate demonstrated that Cr(VI) reduction could occur under either denitrifying or aerobic conditions (at comparable rates), and that reduction was much more rapid when the terminal electron acceptor (i.e., nitrate or O2) was present. It appears that, under both aerobic and denitrifying conditions, the chromate reductase gene(s) are not inducible by Cr; this conclusion is based on the fact that these cell suspension studies were conducted with cells grown in the absence of Cr and resuspended in a buffer that included chloramphenicol, which inhibits protein synthesis. As our studies indicate that anaerobic Cr(VI) reduction by strain RCH2 is much more rapid in the presence of nitrate (i.e., during denitrification) than in its absence, we explored molecular methods that could readily assess in situ denitrification. Specifically, we investigated whether the gene and transcript copy number of diagnostic denitrification genes (nirS and narG) in groundwater could be used to estimate in situ denitrification rates. Continuous culture (chemostat) studies showed strong correlations (r2 values > 0.93) between denitrification rate and either nirS or narG transcript copy number, suggesting that monitoring expression of such genes (and relevant chromate reductase genes, when characterized) in groundwater could provide valuable information for understanding the biogeochemical dynamics of in situ chromate reduction.

  18. Criteria and Methodology for Identifying Respiratory Denitrifiers

    OpenAIRE

    Mahne, I.; Tiedje, J.M.

    1995-01-01

    Respiratory denitrification is not always adequately established when bacteria are characterized. We have tested a simple method that allows one to evaluate whether the two necessary criteria to claim denitrification have been met, namely, that N(inf2) or N(inf2)O is produced from nitrate or nitrite and that this reduction is coupled to a growth yield increase. Microorganisms were cultured in sealed tubes under a helium headspace and in the presence of 0, 2, 4, 7, and 10 mM nitrate or nitrite...

  19. Azoarcus taiwanensis sp. nov., a denitrifying species isolated from a hot spring.

    Science.gov (United States)

    Lee, Duu-Jong; Wong, Biing-Teo; Adav, Sunil S

    2014-02-01

    The strain NSC3(T), a novel, facultative, chemolithotrophic, denitrifying, alkaliphilic, sulfide-oxidizing bacterium isolated from a hot spring in Yang-Ming Mountain, Taiwan, was Gram negative, rod shaped, and motile by single polar flagella and grew facultatively by adopting a denitrifying metabolism. The 16S rRNA sequence analysis revealed that strain NSC3(T) belongs to beta subclass of the Proteobacteria and most closely related to Azoarcus evansii KB740(T) (95.44 %), Azoarcus toluvorans Td-21(T) (95.21 %), Azoarcus tolulyticus Tol-4(T) (95.08 %), and Azoarcus toluclasticus MF63(T) (94.94 %). The phylogenetic analyses based on 16S rRNA gene sequences indicated that the strain NSC3(T) formed a distinct lineage in the Betaproteobacteria and that it exhibited the highest level of sequence similarity with species of the genera Azoarcus (95.28-93.13 %). The major fatty acids of the type strain were C16:0 (26.9 %), C16:1w7c (28.9 %), C18:0 (9.6 %), and C18:1w7c/w6c (29.9 %). The DNA G+C content of genomic DNA was 63.7 mol%. On the basis of the 16S rRNA sequence similarity, phenotypic and genotypic characteristics, and chemotaxonomic data, the strain NSC3(T) could be differentiated from other species of the genus Azoarcus. Therefore, strain NSC3(T) (equal to BCRC 80111(T) and DSM 24109(T)) is proposed as a novel species in genus Azoarcus, for which the name Azoarcus taiwanensis sp. nov. is proposed. The strain NSC3(T) is deposited in Bioresource Collection and Research Center, Taiwan, under the reference number BCRC 80111(T), and German Collection of Microorganisms and Cell Cultures, Germany (DSMZ), with DSM 24109(T). PMID:23695778

  20. Elimination of pharmaceuticals in single- and three-stage pre-denitrifying MBBR

    DEFF Research Database (Denmark)

    Polesel, Fabio; Torresi, Elena; Loreggian, L.; Escola Casas, Monica; Bester, Kai; Plósz, Benedek G.

    This study investigated the elimination of pharmaceuticals in pre-denitrifying moving bed biofilm reactors (MBBRs) in single- and three-stage configurations. Under batch conditions, biotransformation and retransformation of two pharmaceuticals (trimethoprim, sulfamethoxazole) occurred at comparable...... or higher rates than in denitrifying activated sludge. Based on estimated rate coefficients, concentrations in continuously operated MBBRs were predicted....

  1. Cultivo del nematodo Panagrellus redivivus (Goodey, 1945) en un medio de avena enriquecida con Spirulina sp. / Nematode culture of Panagrellus redivivus (Goodey, 1945) with Spirulina sp. - enriched oatmeal

    Scientific Electronic Library Online (English)

    Ramón, de Lara; Thalía, Castro; Jorge, Castro; Germán, Castro.

    2007-04-01

    Full Text Available El nematodo Panagrellus redivivus se cultivó en dos medios: uno con hojuelas de avena y otro con hojuelas de avena enriquecido con Spirulina sp., en recipientes de plástico de 15x15x5 cm de altura con 200 g de hojuela de avena y 300 mL de agua purificada. Se utilizaron 5 g de Spirulina en el medio. [...] Se utilizó el programa SYSTAT versión 10.2 para el análisis estadístico; para determinar las diferencias significativas entre los tratamientos, se usó un análisis de varianza unidireccional (ANDEVA) con una confiabilidad ?= 0,05. Los resultados obtenidos muestran que el crecimiento de las poblaciones de nematodos en el medio enriquecido con Spirulina presentó la mayor abundancia de individuos a la segunda semana del cultivo, mientras que la población que creció en el medio de avena, presentó su mayor registro a la quinta semana del cultivo y no alcanzó el número de organismos que tuvo la población cultivada en el medio con Spirulina. El contenido de aminoácidos de las poblaciones de ambos medios se comparó y se cotejaron con los reportados para Artemia alimentada con Spirulina, observándose que en la mayoría de los aminoácidos las cantidades fueron mayores en P. redivivus cultivado en el medio con Spirulina. La composición de ácidos grasos en los nematodos cultivados en ambos medios presentó diferencias significativas entre los ácidos grasos linoleico, araquidónico y eicosapentenoico los cuales fueron en mayor porcentaje que los reportados en P. redivivus cultivado en avena con aceite de girasol. Estos datos demuestran que la cianobacteria Spirulina sp. acelera el crecimiento de la población del nematodo y permite la presencia de aminoácidos y ácidos grasos, y hace que estos nematodos puedan cubrir los requerimientos nutritivos de larvas de peces dulceacuícolas, sin embargo, se requieren estudios que lo demuestren Abstract in english The nematode Pangrellus redivivus was cultured in two media: one with oat flakes and the other with Spirulina sp.-enriched oat flakes, in 15x15x5 cm plastic containers with 200 g oat flakes and 300 mL purified water. Five grams of Spirulina was used in the medium. SYSTAT version 10.2 was used for st [...] atistical analysis; to determine the significant differences between treatment a unidirectional analysis of variance (ANOVA) was used with a confidence level of ?= 0.05. The results show that growth of the nematode population in the Spirulina-enriched medium presented the highest abundance of individuals on the second week of culture, whereas the population grown in the oat flakes medium showed the highest abundance on the fifth week of culture and did not reach the number of organisms attained by the population cultured in the Spirulina-enriched medium. The amino acids content of the populations from both media were compared to those reported for Artemia fed with Spirulina, observing that the amounts were higher for most amino acids in P. redivivus cultured in the Spirulina-enriched medium. The composition of fatty acids in the nematode cultures in both media depicted significant differences for the linoleic, arachidonic, and eicosapentaenoic fatty acids, which were found in a higher percentage than reported for P. redivivus cultures in oat flakes supplemented with sunflower oil. These data reveal that the cyanobacterium Spirulina sp. accelerates growth of the nematode populations and allows the presence of amino and fatty acids, making these nematodes suitable to cover the nutritional requirements of freshwater fish larvae, but further studies are needed to demonstrate it

  2. Functional gene pyrosequencing reveals core proteobacterial denitrifiers in boreal lakes.

    Science.gov (United States)

    Saarenheimo, Jatta; Tiirola, Marja Annika; Rissanen, Antti J

    2015-01-01

    Denitrification is an important microbial process in aquatic ecosystems that can reduce the effects of eutrophication. Here, quantification and pyrosequencing of nirS, nirK, and nosZ genes encoding for nitrite and nitrous oxide reductases was performed in sediment samples from four boreal lakes to determine the structure and seasonal stability of denitrifying microbial populations. Sediment quality and nitrate concentrations were linked to the quantity and diversity of denitrification genes, the abundance of denitrifying populations (nirS and nosZ genes) correlated with coupled nitrification-denitrification (Dn), and the denitrification of the overlying water NO3 (-) (Dw) correlated with the nirS/nirK ratio. The number of core nirS, nirK, and nosZ operational taxonomical units (OTUs) was low (6, 7, and 3, respectively), and most of these core OTUs were shared among the lakes. Dominant nirK sequences matched best with those of the order Rhizobiales, which was one of the main bacterial orders present in the sediment microbiomes, whereas the dominant nirS sequences were affiliated with the order Burkholderiales. Over half of the nosZ sequences belonged to a single OTU of the order Burkholderiales, but coupled nitrification-denitrification rate correlated with another dominant nosZ OTU assigned to the order Rhodospirillales. The study indicates that a few core proteobacterial clusters may drive denitrification in boreal lake sediments, as the same Alpha- and Betaproteobacteria denitrifier clusters were present in different lakes and seasons. PMID:26191058

  3. Rapid in vitro regeneration method for Moringa oleifera and performance evaluation of field grown nutritionally enriched tissue cultured plants

    OpenAIRE

    R. K. Saini; Shetty, N.P.; Giridhar, P; Ravishankar, G. A.

    2012-01-01

    The present investigations were attempted to develop the rapid in vitro micropropagation protocol of Moringa oleifera (Variety-PKM-1) from nodal sections of young, aseptically grown seedlings. Benzyladenine (BA) at 4.44 ?M was found to be optimal in producing on maximum an average of 9.0 ± 1.0 axillary shoots per explant after 15 days of inoculation. A high multiplication rate was established through routine sub culturing of nodal sections explanted from in vitro shoot cultures. In vitro root...

  4. Interactions of deoxynivalenol and lipopolysaccharides on cytotoxicity protein synthesis and metabolism of DON in porcine hepatocytes and Kupffer cell enriched hepatocyte cultures.

    Science.gov (United States)

    Döll, Susanne; Schrickx, Jan A; Valenta, Hana; Dänicke, Sven; Fink-Gremmels, Johanna

    2009-09-10

    The cytotoxicity of deoxynivalenol (DON), effects on protein synthesis and albumin secretion was investigated in porcine hepatocytes and Kupffer cell-enriched hepatocyte cultures (co-cultures) in the presence and absence of lipopolysaccharides (LPS). Up to 16microM DON did not reduce the metabolic activity of hepatocytes. Lysosomal activity reacted more sensitively as neutral red uptake was decreased starting at 2 or 4microM DON irrespective of LPS exposure. The synthesis of secreted proteins was reduced to 31% and 42%, and of cellular proteins to 47% and 39%, in the absence and presence of LPS, respectively, when hepatocytes were exposed to 2microM DON. Reduced albumin secretion in response to DON was already observed after 3h in hepatocytes as well as co-cultures while LPS-mediated decrease was not evident until 24h, when interactions between DON and LPS resulted from a diminishing difference between LPS stimulated and non-stimulated cultures with increasing concentrations of DON. All observed effects may be biased by the cells' ability to conjugate DON to glucuronic acid as 54% and 64% of DON administered at 5nM were recovered as conjugates after 48h. Glucuronidation rate, as well as total DON recovery, decreased with increasing concentrations of DON, giving rise to assumptions on the formation of undetected metabolites. PMID:19477247

  5. Molecular and Stable Isotope Investigation of Nitrite Respiring Bacterial Communities Capable of Anaerobic Ammonium Oxidation (ANAMMOX) and Denitrifying Anaerobic Methane Oxidation (DAMO) in Nitrogen Contaminated Groundwater

    Science.gov (United States)

    Song, B.; Hirsch, M.; Taylor, J.; Smith, R. L.; Repert, D.; Tobias, C. R.

    2010-12-01

    Anaerobic ammonium oxidation (ANAMMOX) and denitrifying anaerobic methane oxidation (DAMO) are two recently discovered N2 production pathways in the microbial nitrogen cycle. ANAMMOX has been relatively well investigated in various aquatic ecosystems, while DAMO has been examined only in freshwater wetlands. However, neither ANAMMOX nor DAMO have been studied in groundwater ecosystems as microbial N removal processes where they could compliment or compete with denitrification to remediate N contaminated aquifers. Thus, we conducted molecular and stable isotope analyses to detect and measure ANAMMOX and DAMO in a nitrogen contaminated aquifer on Cape Cod, Massachusetts. The study site has a plume of nitrogen contaminated groundwater as a result of continuous discharge of treated wastewater over 60 years. Groundwater was collected from multiport sampling devices installed at two sites, near the waste-water disposal location (A) and more than 3 km down gradient (B) along the contamination plume. Biomass was collected from water samples for DNA extraction and 15N tracer incubation experiments. PCR with specific 16S rRNA gene primers detected the presence of ANAMMOX and DAMO bacteria at both sites. Phylogenetic analysis of 16S rRNA genes revealed that the ANAMMOX community at site A was most associated with Kuenenia spp. while site B had a community more closely related to Brocadia spp. The DAMO communities at the two sites were quite different based on 16S rRNA gene analysis. The communities at site B are closely associated with Candidatus “Methylomirabilis oxyfera”, which is the first enriched DAMO culture. Most of the 16S rRNA sequences detected in site A were related to those found in other DAMO enrichment cultures established from a eutrophic ditch sediment. In order to determine active members of ANAMMOX communities, the transcriptional expression of hydrazine oxidase (hzo) and hydrazine hydrolase (hh) genes was examined at both sites. In addition, 15N tracer incubation experiments were used to measure the rates of ANAMMOX and denitrification. ANAMMOX was found to be higher than denitrification at site A where ANAMMOX accounted for 60% of the 15N2 production. In contrast, denitrification was higher than ANAMMOX at site B where Methylomirabilis spp. were found. Thus, this study clearly demonstrates the potential importance of ANAMMOX and DAMO in the nitrogen removal from groundwater and suggests that detailed characterization of the processes under in situ subsurface conditions could provide new information regarding the ecology of these microbes.

  6. Effects of inorganic salts on denitrifying granular sludge: The acute toxicity and working mechanisms.

    Science.gov (United States)

    Wang, Ru; Zheng, Ping; Ding, A-Qiang; Zhang, Meng; Ghulam, Abbas; Yang, Cheng; Zhao, He-Ping

    2016-03-01

    It is highly significant to investigate the toxicity of inorganic salts to denitrifying granular sludge (DGS) and its mechanism since the application of high-rate denitrification is seriously limited in the treatment of saline nitrogen-rich wastewaters. The batch experiments showed that the IC50 (half inhibition concentration) and LC50 (half lethal concentration) of NaCl, Na2SO4 and Na3PO4 on DGS were 11.46, 21.72, 7.46g/L and 77.35, 100.58, 67.92g/L respectively. Based on the analysis of specific denitrifying activity, the live cell percentage, the cell structure, and the DNA leakage, the toxicity of low salinity was ascribed to the inhibition of denitrifying activity and the toxicity of high salinity was ascribed to both the inhibition of denitrifying activity and the lethality of denitrifying cell. PMID:26773376

  7. Complete genome sequence of Methylophilus sp. TWE2 isolated from methane oxidation enrichment culture of tap-water.

    Science.gov (United States)

    Xia, Fei; Zou, Bin; Shen, Cong; Zhu, Ting; Gao, Xin-Hua; Quan, Zhe-Xue

    2015-10-10

    The non-methane-utilizing methylotroph, Methylophilus sp. TWE2, was isolated from tap-water during the enrichment of methanotrophs with methane. The complete genome sequence of strain TWE2 showed that this bacterium may convert methanol to formaldehyde via catalysis of methanol dehydrogenase (MDH), after which formaldehyde would be assimilated to biomass through the ribulose monophosphate (RuMP) pathway or dissimilated via the tetrahydromethanopterin (H4MPT) pathway. The deficiency of glycolysis and the TCA cycle indicate that strain TWE2 may be an obligate methylotroph. This is the first complete genome sequence of the genus Methylophilus. PMID:26253961

  8. Thermo-acidophillic biohydrogen production from rice bran de-oiled wastewater by Selectively enriched mixed culture

    OpenAIRE

    D.Sivaramakrishna, D.Sreekanth, V.Himabindu, M.Lakshmi Narasu

    2010-01-01

    The present study focuses on the biohydrogen production in an anaerobic batch reactor operated at thermophillic (570C) and acidophilic conditions (pH 6) with rice bran de-oiled wastewater (RBOW) as substrate. The hydrogen generating mixed microflora was enriched from slaughter house sludge (SHS) through acid treatment (pH 3-4, for 24h) coupled with heat treatment (1h at 1000C) to eliminate non-spore forming bacteria and to inhibit the growth of methanogenic bacteria (MB) prior to inoculation ...

  9. Interactions of deoxynivalenol and lipopolysaccharides on cytokine excretion and mRNA expression in porcine hepatocytes and Kupffer cell enriched hepatocyte cultures.

    Science.gov (United States)

    Döll, Susanne; Schrickx, Jan A; Dänicke, Sven; Fink-Gremmels, Johanna

    2009-10-01

    The effects of deoxynivalenol (DON) on the mRNA expression of cytokines and inflammation-related genes, as well as the cytokine secretion of porcine hepatocytes and Kupffer cell enriched hepatocyte cultures (co-cultures), were investigated in the absence or presence of LPS. DON and LPS acted in a synergistic manner with regard to a significantly increased mRNA expression of TNF-alpha in hepatocytes exposed to 500 nM or 2000 nM DON, or non-significant increase in co-cultures after 3h of exposure. TNF-alpha supernatant concentrations were increased due to LPS but did not reflect the synergistic effects with DON as observed at mRNA level. IL-6 mRNA in hepatocyte cultures at 6h paralleled the TNF-alpha supernatant pattern at this time point. In co-cultures and hepatocytes, a DON dose dependent induction of IL-6 mRNA was detected in cells not exposed to LPS. Supernatant concentrations of LPS-induced IL-6 were significantly decreased by 2000 nM DON in both types of cell cultures. Also the mRNA expression of the anti-inflammatory IL-10 was increased by DON to various degrees depending on DON-dose, stimulation with LPS and time point of measurement. After 6h, expression of iNOS was only induced by 2000 nM DON, but not in LPS treated cells. Even if mRNA induction was not paralleled by related supernatant concentrations of TNF-alpha, IL-6 and IL-10 under the conditions of the present investigations, it was clearly demonstrated that DON has the potential to provoke and modulate immunological reactions of porcine liver cells. PMID:19607891

  10. A method for measuring the anoxic biodegradability under denitrifying conditions.

    Science.gov (United States)

    Vázquez-Rodríguez, Gabriela A; Beltrán-Hernández, Rosa Icela; Lucho-Constantino, Carlos Alexander; Blasco, José Luis

    2008-04-01

    A test for assessing the anoxic biodegradability of organic compounds under denitrifying conditions is proposed. The method is based on the recovery and quantification of the CO2 produced, which is evidence of complete biodegradation of the test compound (added as the sole carbon source). The tests were carried out in a mineral medium, with nitrate as electron acceptor. Whole lake sediments, sediment extracts and a commercial inoculum were assayed as a possible inoculum source by means of glucose biodegradability tests. It was found that the sediment extracts constitute a suitable and environmentally-relevant inoculum source, since they add non-significant amounts of carbon to the tests. Two xenobiotic compounds, namely, aniline and phenol, were tested in the aforementioned conditions as well as in a standard aerobic biodegradability test. Both aniline and phenol attained a biodegradation level higher than 60% in a short time period (biodegradable in denitrifying environments. Nevertheless, the kinetics obtained in the anoxic test were slower than in aerobic conditions, and even suggested the accumulation of intermediate metabolites in the case of phenol. The results of this study indicate that the fate of xenobiotic compounds under anoxic conditions differs from that observed in an oxic environment, and therefore it should be considered by standard biodegradability testing procedures. PMID:18096201

  11. An enrichment and acclimation procedure to obtain photo heterotrophic cultures for H{sub 2} production from organic effluents

    Energy Technology Data Exchange (ETDEWEB)

    Acevedo-Benitez, J. A.; Ponce-Noyola, M. T.; Poggi-Varaldo, H. M.

    2009-07-01

    Production of H{sub 2} via photo heterotrophic is an attractive alternative, due to the capacity of photo heterotrophic organisms to convert the organic matter of effluents into H{sub 2}. The objective of our work was to develop a protocol for selecting undefined mixed cultures of photo heterotrophic microorganism with the capability of producing of H{sub 2}. (Author)

  12. Effects of Temperature on Denitrifying Growth and Nitrate Reduction End Products of Comamonas testosteroni Isolated from Estuarine Sediment

    Directory of Open Access Journals (Sweden)

    IMAN RUSMANA

    2007-01-01

    Full Text Available Predictions of seasonal changes in N2O emission that occur in natural estuaries are important to anticipate the future implications of global warming. This study showed the effect of temperature on denitrifying growth and nitrate reduction end product of Comamonas testoteroni isolated from estuarine sediment using both batch and continuous cultures. The ?max values of Comamonas testosteroni grown in anaerobic batch culture were increased with increasing temperature, and the highest ?max was found at 26 °C. Concentrations of nitrate reduced (mg-1 dried weight cells were higher at low temperature. Concentrations of N2 produced were higher at low temperature and the production of N2 was higher than both NO2- and N2O productions

  13. Bacterial diversity of autotrophic enriched cultures from remote, glacial Antarctic, Alpine and Andean aerosol, snow and soil samples

    Science.gov (United States)

    González-Toril, E.; Amils, R.; Delmas, R. J.; Petit, J.-R.; Komárek, J.; Elster, J.

    2009-01-01

    Four different communities and one culture of autotrophic microbial assemblages were obtained by incubation of samples collected from high elevation snow in the Alps (Mt. Blanc area) and the Andes (Nevado Illimani summit, Bolivia), from Antarctic aerosol (French station Dumont d'Urville) and a maritime Antarctic soil (King George Island, South Shetlands, Uruguay Station Artigas), in a minimal mineral (oligotrophic) media. Molecular analysis of more than 200 16S rRNA gene sequences showed that all cultured cells belong to the Bacteria domain. Phylogenetic comparison with the currently available rDNA database allowed sequences belonging to Proteobacteria Alpha-, Beta- and Gamma-proteobacteria), Actinobacteria and Bacteroidetes phyla to be identified. The Andes snow culture was the richest in bacterial diversity (eight microorganisms identified) and the marine Antarctic soil the poorest (only one). Snow samples from Col du Midi (Alps) and the Andes shared the highest number of identified microorganisms (Agrobacterium, Limnobacter, Aquiflexus and two uncultured Alphaproteobacteria clones). These two sampling sites also shared four sequences with the Antarctic aerosol sample (Limnobacter, Pseudonocardia and an uncultured Alphaproteobacteriaclone). The only microorganism identified in the Antarctica soil (Brevundimonas sp.) was also detected in the Antarctic aerosol. Most of the identified microorganisms had been detected previously in cold environments, marine sediments soils and rocks. Air current dispersal is the best model to explain the presence of very specific microorganisms, like those identified in this work, in environments very distant and very different from each other.

  14. A Fungal Cytochrome P-450nor Confers Denitrifying Ability to Tobacco By-2 Cells

    Directory of Open Access Journals (Sweden)

    Babiker M.A. Abdel-Banat

    2008-01-01

    Full Text Available Reactive nitrogen gases progressively contribute to the global warming. Development of gas-gas denitrifying plants that can efficiently reduce reactive nitrogen gases to dinitrogen (N2 could help to mitigate the effect of these gases. Taking the advances in gene manipulation technology, tobacco BY-2 cells were transformed with the fungus Cylindrocarpon tonkinense cytochrome P-450nor2 (Cnor2 gene. The product of this gene acts as nitric oxide reductase (nor. Transgenic BY-2 cell clones cultured in 15N-labelled nitrate (15NO3- actively evolved 15N2O gas up to 35-folds compared to the wild-type cells. In 15N-labelled ammonium (15NH4+, the transgenic and wild-type cells produced comparable amounts of 15N2O. This indicates that ammonium is not a direct substrate for nor and the small amount of N2O observed may be due to the nitrification of ammonium to nitrite. Addition of tungstate (a nitrate reductase inhibitor and cyanide to the transgenic cell cultures strongly inhibited 15N2O production. Activity of nor enzyme was also confirmed by in vitro activity assay. These observations together suggest that Cnor2 is actively expressed and enhanced the reduction of nitrate to N2O in plant cells. This finding indicates that plant cells are capable to tackle the denitrification pathway.

  15. Enrichment of denitrifying methanotrophic bacteria for application after direct low-temperature anaerobic sewage treatment

    OpenAIRE

    Kampman, C.; Hendrickx, T.L.G.; Luesken, F.; van Alen, T. A.; Op den Camp, H. J. M.; Jetten, M. S. M.; Zeeman, G.; Buisman, C.J.N.; Temmink, B.G.

    2012-01-01

    Despite many advantages of anaerobic sewage treatment over conventional activated sludge treatment, it has not yet been applied in temperate zones. This is especially because effluent from low-temperature anaerobic treatment contains nitrogen and dissolved methane. The presence of nitrogen and methane offers the opportunity to develop a reactor in which methane is used as electron donor for denitrification. Such a reactor could be used in a new concept for low-temperature anaerobic sewage tre...

  16. Enrichment of denitrifying phosphorus accumulating organisms (DPAOs) in a continuous flow laboratory scale plant

    International Nuclear Information System (INIS)

    Enhanced Biological Phosphate Removal (EBPR) is a well established method for efficient removal of phosphate during wastewater treatment by using biological instead of chemical phenomena. EBPR is currently implemented at a number of Waste Water Treatment Plants (WWTPs) and usually phosphate removal occurs by recirculating activated sludge between an anaerobic and a aerobic tank. (Author)

  17. Pandoraea oxalativorans sp. nov., Pandoraea faecigallinarum sp. nov. and Pandoraea vervacti sp. nov., isolated from oxalate-enriched culture.

    Science.gov (United States)

    Sahin, Nurettin; Tani, Akio; Kotan, Recep; Sedlácek, Ivo; Kimbara, Kazuhide; Tamer, Abdurrahman U

    2011-09-01

    Five isolates, designated TA2, TA4, TA25(T), KOx(T) and NS15(T) were isolated in previous studies by enrichment in mineral medium with potassium oxalate as the sole carbon source and were characterized using a polyphasic approach. The isolates were Gram-reaction-negative, aerobic, non-spore-forming rods. Phylogenetic analyses based on 16S rRNA and DNA gyrase B subunit (gyrB) gene sequences confirmed that the isolates belonged to the genus Pandoraea and were most closely related to Pandoraea sputorum and Pandoraea pnomenusa (97.2-99.7?% 16S rRNA gene sequence similarity). The isolates could be differentiated from their closest relatives on the basis of several phenotypic characteristics. The major cellular fatty acid profiles of the isolates comprised C??:?, C??:??7c, C??:? cyclo and summed feature 3 (C??:??7c and/or iso-C??:? 2-OH). On the basis of DNA-DNA hybridization studies and phylogenetic analyses, the isolates represent three novel species within the genus Pandoraea, for which the names Pandoraea oxalativorans sp. nov. (TA25(T) ?=?NBRC 106091(T) ?=?CCM 7677(T) ?=?DSM 23570(T)), Pandoraea faecigallinarum sp. nov. (KOx(T) ?=?NBRC 106092(T) ?=?CCM 2766(T) ?=?DSM 23572(T)) and Pandoraea vervacti sp. nov. (NS15(T) ?=?NBRC 106088(T) ?=?CCM 7667(T) ?=?DSM 23571(T)) are proposed. PMID:20952546

  18. Thermo-acidophillic biohydrogen production from rice bran de-oiled wastewater by Selectively enriched mixed culture

    Directory of Open Access Journals (Sweden)

    D.Sivaramakrishna, D.Sreekanth, V.Himabindu, M.Lakshmi Narasu

    2010-07-01

    Full Text Available The present study focuses on the biohydrogen production in an anaerobic batch reactor operated at thermophillic (570C and acidophilic conditions (pH 6 with rice bran de-oiled wastewater (RBOW as substrate. The hydrogen generating mixed microflora was enriched from slaughter house sludge (SHS through acid treatment (pH 3-4, for 24h coupled with heat treatment (1h at 1000C to eliminate non-spore forming bacteria and to inhibit the growth of methanogenic bacteria (MB prior to inoculation in the reactor. The hydrogen production rate was maximum at 570C (1861±14ml/L-WW/d compared to 370C (651±30ml/L-ww/d. The Hydrogen yield increased with temperature from 1.1 to 2.2 molH2/mol of substrate respectively. The optimum pH range for hydrogen production in this system was observed in between 5.5 to 6. Acid-forming pathway with butyric acid as a major metabolite dominated the metabolic flow during the hydrogen production.

  19. Thermo-acidophillic biohydrogen production from rice bran de-oiled wastewater by Selectively enriched mixed culture

    Energy Technology Data Exchange (ETDEWEB)

    Sivaramakrishna, D.; Sreekanth, D.; Himabindu, V. [Centre for Environment, Institute of Science and Technology, Jawaharlal Nehru Technological University Hyderabad, Kukatpally Hyderabad-500 085 (India); Narasu, M. Lakshmi [Centre for Biotechnology, Institute of Science and Technology, Jawaharlal Nehru Technological University Hyderabad, Kukatpally Hyderabad-500 085 (India)

    2010-07-01

    The present study focuses on the biohydrogen production in an anaerobic batch reactor operated at thermophillic (570C) and acidophilic conditions (pH 6) with rice bran de-oiled wastewater (RBOW) as substrate. The hydrogen generating mixed microflora was enriched from slaughter house sludge (SHS) through acid treatment (pH 3-4, for 24h) coupled with heat treatment (1h at 1000C) to eliminate non-spore forming bacteria and to inhibit the growth of methanogenic bacteria (MB) prior to inoculation in the reactor. The hydrogen production rate was maximum at 570C (1861 +- 14ml/L-WW/d) compared to 370C (651 +- 30ml/L-ww/d). The Hydrogen yield increased with temperature from 1.1 to 2.2 molH2/mol of substrate respectively. The optimum pH range for hydrogen production in this system was observed in between 5.5 to 6. Acid-forming pathway with butyric acid as a major metabolite dominated the metabolic flow during the hydrogen production.

  20. Effects of resveratrol on enrichment of adipose-derived stem cells and their differentiation to osteoblasts in two-and three-dimensional cultures.

    Science.gov (United States)

    Erdman, Christopher P; Dosier, Christopher R; Olivares-Navarrete, Rene; Baile, Clifton; Guldberg, Robert E; Schwartz, Zvi; Boyan, Barbara D

    2012-12-01

    The goal of this study was to develop a method for increasing the yield of multipotent adipose-derived mesenchymal stem cells (ASCs) and osteoprogenitor cells (OPCs) from subcutaneous fat. After removing mature adipocytes and haematopoietic cells from rat inguinal fat, ASCs in the remaining cell population were verified by their attachment to plastic, surface marker profile (CD271(+), CD73(+) and CD45(-)) and ability to differentiate into adipocytes, chondrocytes and osteoblasts. OPCs were defined as E11(+) and OCN(+). Adherent cells were cultured in growth medium (GM) or osteogenic medium (OM) and treated with resveratrol (0, 12.5, and 25 µM) for 7 days; ASCs and OPCs were assessed by flow cytometry. Osteogenic potential was determined in two-dimensional (2D) cultures as a function of alkaline phosphatase-specific activity and osteocalcin production. In addition, cells were seeded onto three-dimensional (3D) poly-?-caprolactone scaffolds and cultured under dynamic conditions; mineralization was quantified by micro-CT at 4, 8 and 12 weeks. Resveratrol increased the percentage of ASCs in the population (population%) and number of ASCs in both GM and OM, but increased only the number of OPCs in GM. In both media types resveratrol increased alkaline phosphatase activity and osteocalcin levels. In 3D cultures, resveratrol-treated cells significantly increased mineralized matrix volume at early time points. Resveratrol exerted a biphasic effect on adherent cells by enriching the ASC and OPC populations and enhancing osteogenic differentiation. Resveratrol pretreatment induced more mineralization at earlier time points and represents a clinically viable technique for orthopaedic and dental applications for autologous stem cell therapy. PMID:22467433

  1. Enhanced performance of denitrifying sulfide removal process under micro-aerobic condition

    International Nuclear Information System (INIS)

    The denitrifying sulfide removal (DSR) process with bio-granules comprising both heterotrophic and autotrophic denitrifiers can simultaneously convert nitrate, sulfide and acetate into di-nitrogen gas, elementary sulfur and carbon dioxide, respectively, at high loading rates. This study determines the reaction rate of sulfide oxidized into sulfur, as well as the reduction of nitrate to nitrite, would be enhanced under a micro-aerobic condition. The presence of limited oxygen mitigated the inhibition effects of sulfide on denitrifier activities, and enhanced the performance of DSR granules. The advantages and disadvantages of applying the micro-aerobic condition to the DSR process are discussed.

  2. Aerobic and anaerobic growth of rifampin-resistant denitrifying bacteria in soil.

    OpenAIRE

    Murray, R E; Parsons, L L; Smith, M.S.

    1990-01-01

    The growth and survival of several rifampin-resistant isolates of denitrifying bacteria were examined under anaerobic (denitrifying) and aerobic conditions. Two isolates added to nonsterile Bruno soil at densities of between 10(4) and 10(6) CFU g dry soil-1 exhibited an initial period of growth followed by a gradual decline in numbers. After 28 days, both isolates maintained viable populations of between 10(4) and 10(5) CFU g dry soil-1 under both denitrifying and aerobic conditions. One of t...

  3. Greenhouse Gas Emission from In-situ Denitrifying Bioreactors

    Science.gov (United States)

    Pluer, W.; Walter, M. T.; Geohring, L.

    2013-12-01

    Despite decades of concerted effort to mitigate nonpoint source nitrate (NO3-) pollution from agricultural lands, these efforts have not been sufficient to arrest eutrophication, which continues to be a serious and chronic problem. Two primary processes for removing excess NO3- from water are biological assimilation and denitrification. Denitrifying bacteria use NO3- as the electron acceptor for respiration in the absence of oxygen. Denitrification results in reduced forms of nitrogen, often dinitrogen gas (N2) but also nitrous oxide (N2O), an aggressive greenhouse gas (GHG). A promising solution to NO3- pollution is to intercept agricultural discharges with denitrifying bioreactors (DNBRs), though research has been limited to NO3- level reduction and omitted process mechanisms. DNBRs work by providing an anaerobic environment with plenty of organic matter (commonly woodchips) for denitrifying bacteria to flourish. While, initial results from bioreactor studies show that they can cost-effectively remove NO3-, GHG emission could be an unintended consequence. The study's goal is to determine how bioreactor design promotes microbial denitrification while limiting N2O production. It specifically focuses on expanding the body of knowledge concerning DNBRs in the areas of design implications and internal processes by measuring intermediate compounds and not solely NO3-. Nutrient samples are collected at inflow and outflow structures and tested for NO3- and nitrite (NO2-). Dissolved and headspace gas samples are collected and tested for N2O. Additional gas samples will be analyzed for naturally-occurring isotopic N2 to support proposed pathways. Designs will be analyzed both through the N2O/N2 production ratio and NO2- production caused by various residence times and inflow NO3- concentrations. High GHG ratios and NO2- production suggest non-ideal conditions or flow patterns for complete denitrification. NO3- reduction is used for comparison with previous studies. Few studies have focused on the reactions and products of DNBRs and instead note NO3- reductions in outflows as evidence that this should be used to treat agricultural discharges. It is, however, critical to understand all of the potential impacts that this treatment solution may have, which means identifying processes and design specifications that may affect them. This study addresses this lack of mechanistic understanding of DNBRs by means of sampling for incomplete products. Results will quantify gaseous products and internal processes and present a more complete picture of the potential for widespread use of DNBRs.

  4. Bacterial diversity of autotrophic enriched cultures from remote, glacial Antarctic, Alpine and Andean aerosol, snow and soil samples

    Directory of Open Access Journals (Sweden)

    E. González-Toril

    2009-01-01

    Full Text Available Four different communities and one culture of autotrophic microbial assemblages were obtained by incubation of samples collected from high elevation snow in the Alps (Mt. Blanc area and the Andes (Nevado Illimani summit, Bolivia, from Antarctic aerosol (French station Dumont d'Urville and a maritime Antarctic soil (King George Island, South Shetlands, Uruguay Station Artigas, in a minimal mineral (oligotrophic media. Molecular analysis of more than 200 16S rRNA gene sequences showed that all cultured cells belong to the Bacteria domain. Phylogenetic comparison with the currently available rDNA database allowed sequences belonging to Proteobacteria Alpha-, Beta- and Gamma-proteobacteria, Actinobacteria and Bacteroidetes phyla to be identified. The Andes snow culture was the richest in bacterial diversity (eight microorganisms identified and the marine Antarctic soil the poorest (only one. Snow samples from Col du Midi (Alps and the Andes shared the highest number of identified microorganisms (Agrobacterium, Limnobacter, Aquiflexus and two uncultured Alphaproteobacteria clones. These two sampling sites also shared four sequences with the Antarctic aerosol sample (Limnobacter, Pseudonocardia and an uncultured Alphaproteobacteriaclone. The only microorganism identified in the Antarctica soil (Brevundimonas sp. was also detected in the Antarctic aerosol. Most of the identified microorganisms had been detected previously in cold environments, marine sediments soils and rocks. Air current dispersal is the best model to explain the presence of very specific microorganisms, like those identified in this work, in environments very distant and very different from each other.

  5. Isotope enrichment

    International Nuclear Information System (INIS)

    In this chapter of the textbook for chemists the isotope enrichment methods are overviewed. The subsections are: General characterization of the methods used for isotope enrichment, Distillation and chemical exchange, Electrochemical methods, Diffusion methods, Isotope enrichment through centrifugation, Single-stage methods, Cascades

  6. Determination of the cause of the symptoms on yellow yam (Dioscorea cayenensis Lam.) leaf tissue and their eradication, enriching the culture medium and using techniques of meristem culture, thermo and chemotherapy on in vitro conditions

    International Nuclear Information System (INIS)

    Yams (Dioscorea spp) has been cultivated for exportation in Costa Rica, in North Huetar region. In vitro culture technique has been used for multiplying planting material for many advantages. However, cleaning of viruses that affect has been ineffective. Viruses such as: the potyvirus, potexvirus, cucumovirus . Methods like meristem culture, chemotherapy, thermotherapy and combinations of these have been used for the elimination of virus in plant species. The plants were evaluated in indexing assays, observing symptoms, serological methods and electron microscopy, among others. Other problems that have been affecting in vitro plant are deficient culture media in some nutrient. The presence of some abnormal characteristics in leaf tissue was determined whether have been caused by a virus or a nutritional deficiency in the culture medium. The presence of the virus has tried to find using ELISA and electron microscopy. Tests meristem culture, thermotherapy and chemotherapy have been made for the eradication of a possible virus; which have been assessed by observation of symptomatology and ELISA. The efficiency of the culture medium was evaluated to enrich it with nitrogen or excess iron. None of the suspected virus found in ELISA tests. Filaments are presumably viral particles were found through analysis of ultrastructure, as well as alterations in chloroplasts which indicated the presence of a pathogen or toxicity. Thermotherapy and chemotherapy with the concentration of 40 mg/L of ribavirin have been the most effective for the elimination of symptoms in virus eradication treatments. Assessments nutrient concentrations have shown that the differences between the various treatments used were undetectable. The symptoms presented were caused, according to the conclusions, by a virus which should preferably deal with thermotherapy. (author)

  7. Denitrifying sulfide removal process on high-tetracycline wastewater.

    Science.gov (United States)

    Liu, Chunshuang; Xu, Jian; Lee, Duu-Jong; Yu, Daoyong; Liu, Lihong

    2016-04-01

    Antibiotics wastewater from tetracycline (TC) production unit can have high levels of chemical oxygen demand, ammonium and sulfate and up to a few hundreds of milligrams per liter of TC. Denitrifying sulfide removal (DSR) process is set up for simultaneously removal of sulfur, carbon and nitrogen from waters. The DSR process was for the first time studied for treating TC wastewaters. The TC stress has no adverse effects on removal rates of nitrate and acetate; however, it moderately deteriorated sulfide removal rates and S(0) accumulation rates when the concentration is higher than 100mgL(-1) TC. The Thauera sp., and Pseudomonas sp. present the heterotrophs and Sulfurovum sp. presented the autotroph for the present DSR reactions. The high tolerance of TC stress by the tested consortium was explained by the excess production of extracellular polymeric substances at high TC concentration, which can bind with TC for minimizing its inhibition effects. PMID:26810146

  8. Porównawcze badania nad wyst?powaniem bakterii w hydroponicznych uprawach sa?aty (Lactuca sativa L. z azotanowa? i amonow? form? azotu w po?ywce [Comparative studies on the occurrence of bacteria in hydroponic cultures of lettuce (Lactuca sativa L. enriched with nitrate or ammonia forms of nitrogen in the nutrient medium

    Directory of Open Access Journals (Sweden)

    Z. Kobierzy?ska-Go??b

    2015-06-01

    Full Text Available The experiment demonstrated the greatest number of bacteria on the surface of roots immersed in nutrient solution, next on the epidermis of the parts of roots remaining in the air space above the nutrient solution and on the roots growing in the seed-bed; a smaller number in the seed-bed itself and the smallest number in the nutrient solution. The population of bacteria consisted of up to 90% short rod of bacilli. The total number of bacteria in hydroponic culture with ammonium was higher than in that with nitrate. As a rule the bacteria belonging to the separate physiological groups, participating in nitrogen metabolism (ammonifying, proteolytic, proteinizing, denitrifying and oligonitrophilic bacteria appeared to be more numerus in the culture with ammonium than in that with nitrate. The growth of plants in hydroponic culture with ammonium was weaker than in that with nitrate.

  9. Heavy metal incorporation in foraminiferal calcite: results from multi-element enrichment culture experiments with Ammonia tepida

    Directory of Open Access Journals (Sweden)

    G.-J. Reichart

    2010-08-01

    Full Text Available The incorporation of heavy metals into carbonate tests of the shallow water benthic foraminifer Ammonia tepida was investigated under controlled laboratory conditions. Temperature, salinity, and pH of the culture solutions were kept constant throughout the duration of this experiment, while trace metal concentrations were varied. Concentrations of Ni, Cu, and Mn were set 5-, 10-, and 20 times higher than levels found in natural North Sea water; for reference, a control experiment with pure filtered natural North Sea water was also analysed. The concentrations of Cu and Ni from newly grown chambers were determined by means of both ?-synchrotron XRF and Laser Ablation Inductively Coupled Plasma Mass Spectroscopy (LA-ICP-MS. The results of both independent analytical techniques agreed within the analytical uncertainty. In general, the concentration of the analysed elements in the tests increased in line with their concentration in the culture solutions. Potential toxic and/or chemical competition effects might have resulted in the decreased incorporation of Ni and Cu into the calcite of the specimens exposed to the highest elemental concentrations. Mn incorporation exhibited large variability in the experiment with the 20-fold increased element concentrations, potentially due to antagonistic effects with Cu. The partition coefficients of Cu and Ni were calculated to be 0.14 ± 0.02 and 1.0 ± 0.5, respectively, whereas the partition coefficient of Mn was estimated to be least 2.4. These partition coefficients now open the way for reconstructing past concentrations for these elements in sea water.

  10. INHIBITION OF ALKYLBENZENE BIODEGRADATION UNDER DENITRIFYING CONDITIONS BY USING THE ACETYLENE BLOCK TECHNIQUE

    Science.gov (United States)

    Addition of acetylene to microcosms simultaneously amended with nitrate and alkylbenzenes resulted in inhibition of the rate of alkylbenzene biodegradation under denitrifying conditions. Toluene, xylenes, and 1,2,4-trimethylbenzene were recalcitrant, whereas ethylbenzene was degr...

  11. Properties and electron transfer specificity of copper proteins from the denitrifier "Achromobacter cycloclastes".

    OpenAIRE

    Liu, M. Y.; M. C. Liu; Payne, W. J.; LeGall, J.

    1986-01-01

    A blue copper protein (Mr 12,000) was purified from cells of "Achromobacter cycloclastes" grown as a denitrifier. When reduced, the blue copper protein transferred electrons to the copper protein nitrite reductase purified from the same cells, whereas a variety of cytochromes from denitrifiers failed to do so. Inclusion of a protease inhibitor, phenylmethylsulfonyl fluoride, in the buffers employed during preparation yielded purified blue copper protein with 18 more amino acid residues and tw...

  12. Soil Resources Influence Spatial Patterns of Denitrifying Communities at Scales Compatible with Land Management? †

    OpenAIRE

    Enwall, Karin; Throbäck, Ingela N.; Stenberg, Maria; Söderström, Mats; Hallin, Sara

    2010-01-01

    Knowing spatial patterns of functional microbial guilds can increase our understanding of the relationships between microbial community ecology and ecosystem functions. Using geostatistical modeling to map spatial patterns, we explored the distribution of the community structure, size, and activity of one functional group in N cycling, the denitrifiers, in relation to 23 soil parameters over a 44-ha farm divided into one organic and one integrated crop production system. The denitrifiers were...

  13. A Comparative Study of the Bacterial Community in Denitrifying and Traditional Enhanced Biological Phosphorus Removal Processes

    OpenAIRE

    Lv, Xiao-Mei; Shao, Ming-Fei; Li, Chao-Lin; Li, Ji; Gao, Xin-lei; Sun, Fei-Yun

    2014-01-01

    Denitrifying phosphorus removal is an attractive wastewater treatment process due to its reduced carbon source demand and sludge minimization potential. Two lab-scale sequencing batch reactors (SBRs) were operated in alternating anaerobic-anoxic (A-A) or anaerobic-oxic (A-O) conditions to achieve denitrifying enhanced biological phosphate removal (EBPR) and traditional EBPR. No significant differences were observed in phosphorus removal efficiencies between A-A SBR and A-O SBR, with phosphoru...

  14. Identification of active denitrifiers in full-scale nutrient removal wastewater treatment systems

    DEFF Research Database (Denmark)

    McIlroy, Simon Jon; Szyszka, Anna; Starnawski, Piotr Marian; Saunders, Aaron Marc; Nierychlo, Marta; Nielsen, Per Halkjær; Nielsen, Jeppe Lund

    2015-01-01

    Denitrification is essential to the removal of nitrogen from wastewater during treatment, yet an understanding of the diversity of the active denitrifying bacteria responsible in full-scale wastewater treatment plants (WWTP) is lacking. In this study stable isotope probing (SIP) was applied in combination with microautoradiography (MAR)-fluorescence in situ hybridisation (FISH) to identify the active denitrifiers in a full-scale WWTP with biological N and P removal. Recognising that a range of c...

  15. Identification of active denitrifiers in full-scale nutrient removal wastewater treatment systems

    DEFF Research Database (Denmark)

    Mcllroy, Simon; Starnawska, Anna; Starnawski, Piotr; Saunders, Aaron M.; Nierychlo, Marta; Nielsen, Per Halkjær; Nielsen, Jeppe Lund

    2015-01-01

    Denitrification is essential to the removal of nitrogen from wastewater during treatment, yet an understanding of the diversity of the active denitrifying bacteria responsible in full-scale wastewater treatment plants (WWTPs) is lacking. In this study, stable-isotope probing (SIP) was applied in combination with microautoradiography (MAR)-fluorescence in situ hybridization (FISH) to identify previously unrecognized active denitrifying phylotypes in a full-scale WWTP with biological N and P remov...

  16. Nitrogen removal from micro-polluted reservoir water by indigenous aerobic denitrifiers.

    Science.gov (United States)

    Huang, Ting-Lin; Zhou, Shi-Lei; Zhang, Hai-Han; Zhou, Na; Guo, Lin; Di, Shi-Yu; Zhou, Zi-Zhen

    2015-01-01

    Treatment of micro-polluted source water is receiving increasing attention because of environmental awareness on a global level. We isolated and identified aerobic denitrifying bacteria Zoogloea sp. N299, Acinetobacter sp. G107, and Acinetobacter sp. 81Y and used these to remediate samples of their native source water. We first domesticated the isolated strains in the source water, and the 48-h nitrate removal rates of strains N299, G107, and 81Y reached 33.69%, 28.28%, and 22.86%, respectively, with no nitrite accumulation. We then conducted a source-water remediation experiment and cultured the domesticated strains (each at a dry cell weight concentration of 0.4 ppm) together in a sample of source water at 20-26 °C and a dissolved oxygen concentration of 3-7 mg/L for 60 days. The nitrate concentration of the system decreased from 1.57 ± 0.02 to 0.42 ± 0.01 mg/L and that of a control system decreased from 1.63 ± 0.02 to 1.30 ± 0.01 mg/L, each with no nitrite accumulation. Total nitrogen of the bacterial system changed from 2.31 ± 0.12 to 1.09 ± 0.01 mg/L, while that of the control system changed from 2.51 ± 0.13 to 1.72 ± 0.06 mg/L. The densities of aerobic denitrification bacteria in the experimental and control systems ranged from 2.8 × 10(4) to 2 × 10(7) cfu/mL and from 7.75 × 10(3) to 5.5 × 10(5) cfu/mL, respectively. The permanganate index in the experimental and control systems decreased from 5.94 ± 0.12 to 3.10 ± 0.08 mg/L and from 6.02 ± 0.13 to 3.61 ± 0.11 mg/L, respectively, over the course of the experiment. Next, we supplemented samples of the experimental and control systems with additional bacteria or additional source water and cultivated the systems for another 35 days. The additional bacteria did little to improve the water quality. The additional source water provided supplemental carbon and brought the nitrate removal rate in the experimental system to 16.97%, while that in the control system reached only 3.01%, with no nitrite accumulation in either system. Our results show that aerobic denitrifying bacteria remain highly active after domestication and demonstrate the applicability of such organisms in the bioremediation of oligotrophic ecosystems. PMID:25867475

  17. The social cost of coastal erosion. Using cultural theory to enrich the interpretation of stated preference data.

    Science.gov (United States)

    Kontogianni, A.; Tourkolias, C.; Vousdoukas, M.; Skourtos, M.

    2012-04-01

    Natural coastal processes are to a great extent modified by proximity to man-made structures. Engineered interventions, port facilities, housing and industrial infrastructure, all can increase the coastline fluctuations significantly relative to those along a long unobstructed coastline. As a consequence, coastlines are increasingly exposed to coastal erosion, a phenomenon defined as the encroachment of land by the sea after averaging over a period, which is sufficiently long to eliminate the impacts of weather, storm events and local sediment dynamics. In order to provide cost effective management of coastal erosion it is crucial to estimate both the benefits and costs associated with various management alternatives. The initiatives on Integrated Coastal Zone Manegment in Europe, but also the upcoming Marine Strategy Framwork Directive would benefit greatly from a proliferation of socioeconomic information to assist decision makers who must weigh the impacts of various types of coastal improvement and the cost of beach protection/restoration. In that spirit, the objective of the present research is to report the results of a survey undertaken in two resort beaches on the island of Lesvos (Greece), designed to estimate public preferences for avoiding coastal erosion. A mixed methodological approach is employed by combining an open-ended contingent valuation survey with cultural theory of risk perception. The empirical models to analyze individual choices of erosion control programs and the associated welfare measures are presented, followed by the discussion of model specification and estimation issues, and the results of the data analysis. Some concluding remarks are then presented. By choosing this approach we aim at improving our understanding of preference structure for avoiding public risk, accepted level of risk and perceptions thereof. The framework can also be used for assessing the social cost of extreme weather events such as storm surges in the coastal zone, to get an insight for insurance values.

  18. Growth characteristics of aquatic macrophytes cultured in nutrient-enriched water. I. Water hyacinth, water lettuce, and pennywort

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, K.R.; DeBusk, W.F.

    Seasonal growth characteristics and biomass yield potential of 3 floating aquatic macrophytes cultured in nutrient nonlimiting conditions were evaluated in central Florida's climatic conditions. Growth cycle (growth curve) of the plants was found to be complete when maximum plant density was reached and no additional increase in growth was recorded. Biomass yield per unit area and time was found to be maximum in the linear phase of the growth curve; plant density in this phase was defined as operational plant density, a density range in which a biomass production system is operated to obtain the highest possible yields. Biomass yields were found to be 106, 72, and 41 t (dry wt) ha/sup -1/ yr/sup -1/, respectively, for water hyacinth (Eichhornia crassipes), water lettuce (Pistia stratiotes), and pennywort (Hydrocotyle umbellata). Operational plant density was found to be in the range of 500-2,000 g dry wt m/sup -2/ for water hyacinth, 200-700 g dry wt m/sup -2/ for water lettuce, and 250-650 g dry wt m/sup -2/ for pennywort. Seasonality was observed in growth rates but not in operational plant density. Specific growth rate (% increase per day) was found to maximum at low plant densities and decreased as the plant density increased. Results show that water hyacinth and water lettuce can be successfully grown for a period of about 10 mo, while pennywort, a cool season plant, can be integrated into water hyacinth/water lettuce biomass production system to obtain high yields in the winter.

  19. Growth characteristics of aquatic macrophytes cultured in nutrient-enriched water. I. Water hyacinth, water lettuce, and pennywort

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, K.R.; DeBusk, W.F.

    Seasonal growth characteristics and biomass yield potential of 3 floating aquatic macrophytes cultured in nutrient nonlimiting conditions were evaluated in central Florida's climatic conditions. Growth cycle (growth curve) of the plants was found to be complete when maximum plant density was reached and no additional increase in growth was recorded. Biomass yield per unit area and time was found to be maximum in the linear phase of the growth curve; plant density in this phase was defined as ''operational plant density,'' a density range in which a biomass production system is operated to obtain the highest possible yields. Biomass yields were found to be 106, 72, and 41 t(dry wt) ha/sup -1/yr/sup -1/, respectively, for water hyacinth (Eichhornia crassipes), water lettuce (Pistia stratiotes), and pennywort (Hydrocotyle umbellata). Operational plant density was found to be in the range of 500-2000 g dry wt m/sup -2/ for water hyacinth, 200-700 g dry wt m/sup -2/ for water lettuce, and 250-650 g dry wt/sup -2/ for pennywort. Seasonality was observed in growth rates but not in operational plant density. Specific growth rate (% increase per day) was found to maximum at low plant densities and decreased as the plant density increased. Results show that water hyacinth and water lettuce can be successfully grown for a period of about 10 mo, while pennywort, a cool season plant, can be integrated into water hyacinth/water lettuce biomass production system to obtain high yields in the winter.

  20. Spatial distribution of total, ammonia-oxidizing, and denitrifying bacteria in biological wastewater treatment reactors for bioregenerative life support

    Science.gov (United States)

    Sakano, Yuko; Pickering, Karen D.; Strom, Peter F.; Kerkhof, Lee J.; Janes, H. W. (Principal Investigator)

    2002-01-01

    Bioregenerative life support systems may be necessary for long-term space missions due to the high cost of lifting supplies and equipment into orbit. In this study, we investigated two biological wastewater treatment reactors designed to recover potable water for a spacefaring crew being tested at Johnson Space Center. The experiment (Lunar-Mars Life Support Test Project-Phase III) consisted of four crew members confined in a test chamber for 91 days. In order to recycle all water during the experiment, an immobilized cell bioreactor (ICB) was employed for organic carbon removal and a trickling filter bioreactor (TFB) was utilized for ammonia removal, followed by physical-chemical treatment. In this study, the spatial distribution of various microorganisms within each bioreactor was analyzed by using biofilm samples taken from four locations in the ICB and three locations in the TFB. Three target genes were used for characterization of bacteria: the 16S rRNA gene for the total bacterial community, the ammonia monooxygenase (amoA) gene for ammonia-oxidizing bacteria, and the nitrous oxide reductase (nosZ) gene for denitrifying bacteria. A combination of terminal restriction fragment length polymorphism (T-RFLP), sequence, and phylogenetic analyses indicated that the microbial community composition in the ICB and the TFB consisted mainly of Proteobacteria, low-G+C gram-positive bacteria, and a Cytophaga-Flexibacter-Bacteroides group. Fifty-seven novel 16S rRNA genes, 8 novel amoA genes, and 12 new nosZ genes were identified in this study. Temporal shifts in the species composition of total bacteria in both the ICB and the TFB and ammonia-oxidizing and denitrifying bacteria in the TFB were also detected when the biofilms were compared with the inocula after 91 days. This result suggests that specific microbial populations were either brought in by the crew or enriched in the reactors during the course of operation.

  1. Analysis of denitrifier community in a bioaugmented sequencing batch reactor for the treatment of coking wastewater containing pyridine and quinoline

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Yaohui; Xing, Rui; Wen, Donghui; Tang, Xiaoyan [Peking Univ., Beijing (CN). Key Lab. of Water and Sediment Sciences (Ministry of Education); Sun, Qinghua [Peking Univ., Beijing (CN). Key Lab. of Water and Sediment Sciences (Ministry of Education); Chinese Center for Disease Control and Prevention, Beijing (China). Inst. of Environmental Health and Related Product Safety

    2011-05-15

    The denitrifier community and associated nitrate and nitrite reduction in the bioaugmented and general sequencing batch reactors (SBRs) during the treatment of coking wastewater containing pyridine and quinoline were investigated. The efficiency and stability of nitrate and nitrite reduction in SBR was considerably improved after inoculation with four pyridine- or quinoline-degrading bacterial strains (including three denitrifying strains). Terminal restriction fragment length polymorphism (T-RFLP) based on the nosZ gene revealed that the structures of the denitrifier communities in bioaugmented and non-bioaugmented reactors were distinct and varied during the course of the experiment. Bioaugmentation protected indigenous denitrifiers from disruptions caused by pyridine and quinoline. Clone library analysis showed that one of the added denitrifiers comprised approximately 6% of the denitrifier population in the bioaugmented sludge. (orig.)

  2. Development and evaluation of a loop-mediated isothermal amplification assay combined with enrichment culture for rapid detection of very low numbers of Vibrio parahaemolyticus in seafood samples.

    Science.gov (United States)

    Di, Huiling; Ye, Lei; Neogi, Sucharit Basu; Meng, Hecheng; Yan, He; Yamasaki, Shinji; Shi, Lei

    2015-01-01

    The aim of this study was to develop and evaluate a rapid and effective method to detect Vibrio parahaemolyticus, a leading pathogen causing seafood-borne gastroenteritis. A newly designed loop-mediated isothermal amplification (LAMP) assay including a short enrichment period was optimized. This assay correctly detected all the target strains (n=61) but none of the non-target strains (n=34). Very low numbers of V. parahaemolyticus (2 colony forming unit (CFU) per gram of seafood) could be detected within 3 h and the minimum time of the whole assay was only 5 h. Comparative screening of various seafood samples (n=70) indicated that the LAMP assay is superior to polymerase chain reaction (PCR) and conventional culture methods because it is more rapid and less complex. This highly sensitive LAMP assay can be applicable as the method of choice in large-scale and rapid screening of seafood and environmental samples to detect V. parahaemolyticus strains. PMID:25744462

  3. CD133-enriched Xeno-Free human embryonic-derived neural stem cells expand rapidly in culture and do not form teratomas in immunodeficient mice

    Directory of Open Access Journals (Sweden)

    Daniel L. Haus

    2014-09-01

    Full Text Available Common methods for the generation of human embryonic-derived neural stem cells (hNSCs result in cells with potentially compromised safety profiles due to maintenance of cells in conditions containing non-human proteins (e.g. in bovine serum or on mouse fibroblast feeders. Additionally, sufficient expansion of resulting hNSCs for scaling out or up in a clinically relevant time frame has proven to be difficult. Here, we report a strategy that produces hNSCs in completely “Xeno-Free” culture conditions. Furthermore, we have enriched the hNSCs for the cell surface marker CD133 via magnetic sorting, which has led to an increase in the expansion rate and neuronal fate specification of the hNSCs in vitro. Critically, we have also confirmed neural lineage specificity upon sorted hNSC transplantation into the immunodeficient NOD-scid mouse brain. The future use or adaptation of these protocols has the potential to better facilitate the advancement of pre-clinical strategies from the bench to the bedside.

  4. Denitrifying bacteria from the terrestrial subsurface exposed to mixed waste contamination

    International Nuclear Information System (INIS)

    In terrestrial subsurface environments where nitrate is a critical groundwater contaminant, few cultivated representatives are available with which to verify the metabolism of organisms that catalyze denitrification. In this study, five species of denitrifying bacteria from three phyla were isolated from subsurface sediments exposed to metal radionuclide and nitrate contamination as part of the U.S. Department of Energy's Oak Ridge Integrated Field Research Challenge (OR-IFRC). Isolates belonged to the genera Afipia and Hyphomicrobium (Alphaproteobacteria), Rhodanobacter (Gammaproteobacteria), Intrasporangium (Actinobacteria) and Bacillus (Firmicutes). Isolates from the phylum Proteobacteria were confirmed as complete denitrifiers, whereas the Gram-positive isolates reduced nitrate to nitrous oxide. Ribosomal RNA gene analyses reveal that bacteria from the genus Rhodanobacter comprise a diverse population of circumneutral to moderately acidophilic denitrifiers at the ORIFRC site, with a high relative abundance in areas of the acidic source zone. Rhodanobacter species do not contain a periplasmic nitrite reductase and have not been previously detected in functional gene surveys of denitrifying bacteria at the OR-IFRC site. Sequences of nitrite and nitrous oxide reductase genes were recovered from the isolates and from the terrestrial subsurface by designing primer sets mined from genomic and metagenomic data and from draft genomes of two of the isolates. We demonstrate that a combination of cultivation, genomic and metagenomic data are essential to the in situ characterization of denitrifiers and that current PCR-based approaches are not suitable for deep coverage of denitrifying microorganisms. Our results indicate that the diversity of denitrifiers is significantly underestimated in the terrestrial subsurface.

  5. Microbial diversity in methanogenic hydrocarbon-degrading enrichment cultures isolated from a water-flooded oil reservoir (Dagang oil field, China)

    Science.gov (United States)

    Jiménez, Núria; Cai, Minmin; Straaten, Nontje; Yao, Jun; Richnow, Hans H.; Krüger, Martin

    2015-04-01

    Microbial transformation of oil to methane is one of the main degradation processes taking place in oil reservoirs, and it has important consequences as it negatively affects the quality and economic value of the oil. Nevertheless, methane could constitute a recovery method of carbon from exhausted reservoirs. Previous studies combining geochemical and isotopic analysis with molecular methods showed evidence for in situ methanogenic oil degradation in the Dagang oil field, China (Jiménez et al., 2012). However, the main key microbial players and the underlying mechanisms are still relatively unknown. In order to better characterize these processes and identify the main microorganisms involved, laboratory biodegradation experiments under methanogenic conditions were performed. Microcosms were inoculated with production and injection waters from the reservoir, and oil or 13C-labelled single hydrocarbons (e.g. n-hexadecane or 2-methylnaphthalene) were added as sole substrates. Indigenous microbiota were able to extensively degrade oil within months, depleting most of the n-alkanes in 200 days, and producing methane at a rate of 76 ± 6 µmol day-1 g-1 oil added. They could also produce heavy methane from 13C-labeled 2-methylnaphthalene, suggesting that further methanogenesis may occur from the aromatic and polyaromatic fractions of Dagang reservoir fluids. Microbial communities from oil and 2-methyl-naphthalene enrichment cultures were slightly different. Although, in both cases Deltaproteobacteria, mainly belonging to Syntrophobacterales (e.g. Syntrophobacter, Smithella or Syntrophus) and Clostridia, mostly Clostridiales, were among the most represented taxa, Gammaproteobacteria could be only identified in oil-degrading cultures. The proportion of Chloroflexi, exclusively belonging to Anaerolineales (e.g. Leptolinea, Bellilinea) was considerably higher in 2-methyl-naphthalene degrading cultures. Archaeal communities consisted almost exclusively of representatives of Methanomicrobia (mainly belonging to genera Methanosaeta and Methanoculleus). As both syntrophic Bacteria and methanogenic Archaea are abundant in Dagang, the studied areas of this oil field may have a significant potential to test the in situ conversion of oil into methane as a possible way to increase total hydrocarbon recovery.

  6. Anaerobic degradation of toluene by a denitrifying bacterium.

    Science.gov (United States)

    Evans, P J; Mang, D T; Kim, K S; Young, L Y

    1991-01-01

    A denitrifying bacterium, designated strain T1, that grew with toluene as the sole source of carbon under anaerobic conditions was isolated. The type of agar used in solid media and the toxicity of toluene were determinative factors in the successful isolation of strain T1. Greater than 50% of the toluene carbon was oxidized to CO2, and 29% was assimilated into biomass. The oxidation of toluene to CO2 was stoichiometrically coupled to nitrate reduction and denitrification. Strain T1 was tolerant of and grew on 3 mM toluene after a lag phase. The rate of toluene degradation was 1.8 mumol min-1 liter-1 (56 nmol min-1 mg of protein-1) in a cell suspension. Strain T1 was distinct from other bacteria that oxidize toluene anaerobically, but it may utilize a similar biochemical pathway of oxidation. In addition, o-xylene was transformed to a metabolite in the presence of toluene but did not serve as the sole source of carbon for growth of strain T1. This transformation was dependent on the degradation of toluene. Images PMID:2059037

  7. Nutrient removal efficiency in a rice-straw denitrifying bioreactor.

    Science.gov (United States)

    Liang, Xinqiang; Lin, Limin; Ye, Yushi; Gu, Jiatao; Wang, Zhibo; Xu, Lixian; Jin, Yi; Ru, Qiukai; Tian, Guangming

    2015-12-01

    Rice straw was used as a carbon source in a denitrifying bioreactor, for the removal of nutrients from agricultural drainage. Nutrient removal efficiency was evaluated by: (a) nutrient loading rates (low, medium, and high); (b) hydraulic retention time, and (c) comparison with another carbon source (woodchip). The results show that concentrations of nitrate nitrogen (NO3(-)-N), ammonia nitrogen (NH4(+)-N), total nitrogen (TN), and orthophosphate phosphorus (PO4(3-)-P) in the rice-straw bioreactor effluents were reduced by 53%, 25%, 40%, and 35%, respectively, compared with influents at the medium nutrient loading rate (NO3(-)-N: 10-15mgNL(-1), NH4(+)-N: 10-15mgNL(-1), PO4(3-)-P: 1.0-1.5mgPL(-1)) and long hydraulic retention time (HRT, 24h), with a corresponding denitrification rate (DR) of 0.40mgNL(-1)h(-1). Moreover, the rice-straw bioreactor showed significantly higher (p<0.05) nutrient removal efficiency than the woodchip bioreactor at the medium nutrient loading rate and 24h HRT. PMID:26454040

  8. Uranium enrichment

    International Nuclear Information System (INIS)

    Canada is the world's largest producer and exporter of uranium, most of which is enriched elsewhere for use as fuel in LWRs. The feasibility of a Canadian uranium-enrichment enterprise is therefore a perennial question. Recent developments in uranium-enrichment technology, and their likely impacts on separative work supply and demand, suggest an opportunity window for Canadian entry into this international market. The Canadian opportunity results from three particular impacts of the new technologies: 1) the bulk of the world's uranium-enrichment capacity is in gaseous diffusion plants which, because of their large requirements for electricity (more than 2000 kW·h per SWU), are vulnerable to competition from the new processes; 2) the decline in enrichment costs increases the economic incentive for the use of slightly-enriched uranium (SEU) fuel in CANDU reactors, thus creating a potential Canadian market; and 3) the new processes allow economic operation on a much smaller scale, which drastically reduces the investment required for market entry and is comparable with the potential Canadian SEU requirement. The opportunity is not open-ended. By the end of the century the enrichment supply industry will have adapted to the new processes and long-term customer/supplier relationships will have been established. In order to seize the opportunity, Canada must become a credible supplier during this century

  9. Uranium enrichment

    International Nuclear Information System (INIS)

    This report is a collection of chapters each outlining a different aspect of uranium enrichment. These include different technological procedures for enrichment with specific attention on: the Netherlands' ultracentrifuge; the market and economic situation; political and social implications as well as environmental problems; the history and decision-making at the governmental level which led to the treaty of Almelo; regional aspects; and finally a state-of-the-art evaluation. The report was composed solely on publicly-available data

  10. Improvement of sensitivity for Mycobacterium avium subsp. paratuberculosis (MAP) detection in bovine fecal samples by specific duplex F57/IC real-time and conventional IS900 PCRs after solid culture enrichment.

    Science.gov (United States)

    Fawzy, Ahmad; Eisenberg, Tobias; El-Sayed, Amr; Zschöck, Michael

    2015-04-01

    Mycobacterium avium subsp. paratuberculosis (MAP) is the etiological agent of Johne's disease in ruminants and a probable pathogen of Crohn's disease in humans. Accurate, cost-effective, and time-relevant diagnostics are the basis for efficient control programs. This study was conducted as an attempt to re-evaluate MAP detection improvement by coupling solid media enrichment to a more specific IS900 conventional PCR and a very specific F57/IC real-time PCR. In a spiking experiment, we investigated the improvement of molecular-based MAP detection in feces after a culture-based enrichment step into Herrold's egg yolk media with mycobactin J (HEYM-MJ) for different time intervals, when compared to traditional culture. Detection limit of culture was 0.33?×?10(4) bacteria?×?g(-1) (33 CFU g(-1)), while that of IS900 PCR when coupled with an enrichment step for 2, 4, and 6 weeks was 0.33?×?10(5) (0.33?×?10(3) CFU g(-1)), 0.33?×?10(4) (33 CFU g(-1)), and 33 (>3.3 CFU g(-1)) bacteria?×?g(-1), respectively. Whereas the detection limits of F57/IC real-time PCR after the enrichment step for the same time intervals were 0.33?×?10(5) (0.33?×?10(3) CFU g(-1)), 0.33?×?10(3) (3.3 CFU g(-1)), and 33 (>3.3 CFU g(-1)) bacteria?×?g(-1), respectively. Altogether, enrichment of bovine fecal samples into solid media increased the sensitivity of specific molecular detection of MAP using IS900 conventional PCR and duplex F57/IC real-time PCR and offers an expedited and accurate alternative for MAP detection in bovine feces. Validation of these results is further recommended using field bovine fecal samples. PMID:25716216

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

    Science.gov (United States)

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

    2014-08-01

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

  12. Differential isotopic fractionation during Cr(VI) reduction by an aquifer-derived bacterium under arobic versus denitrifying conditions

    Energy Technology Data Exchange (ETDEWEB)

    Han, R.; Qin, L.; Brown, S. T.; Christensen, J. N.; Beller, H. R.

    2012-02-01

    We studied Cr isotopic fractionation during Cr(VI) reduction by Pseudomonas stutzeri strain RCH2. Despite the fact that strain RCH2 reduces Cr(VI) co-metabolically under both aerobic and denitrifying conditions and at similar specific rates, fractionation was markedly different under these two conditions (ε ~2? aerobically and ~0.4? under denitrifying conditions).

  13. Draft Genome Sequence of Marinobacter sp. Strain P4B1, an Electrogenic Perchlorate-Reducing Strain Isolated from a Long-Term Mixed Enrichment Culture of Marine Bacteria

    Science.gov (United States)

    Stepanov, Victor G.; Xiao, Yeyuan; Lopez, April J.

    2016-01-01

    The perchlorate-reducing strain Marinobacter sp. strain P4B1 was isolated from a long-term perchlorate-degrading enrichment culture seeded with marine sediment. The draft genome of Marinobacter sp. P4B1 is comprised of the bacterial chromosome (3.60 Mbp, G+C 58.51%, 3,269 predicted genes) and its associated plasmid pMARS01 (0.14 Mbp, G+C 52.95%, 165 predicted genes). PMID:26798109

  14. Concurrent Activity of Anammox and Denitrifying Bacteria in the Black Sea

    Directory of Open Access Journals (Sweden)

    JohnB.Kirkpatrick

    2012-07-01

    Full Text Available After the discovery of ANaerobic AMMonium OXidation (anammox in the Black Sea in 2003, the role of heterotrophic denitrification as the main marine pathway for fixed N loss was questioned. A 3 part, 15 month time series investigating Black Sea nitrite reductase (nirS mRNA transcripts at a single location was conducted in order to better understand the activity of anammox and denitrifying bacteria. Here we show that both of these groups were active, as well as being concurrent in the lower suboxic zone over this time span. Their distributions, however, were fundamentally different; denitrification expression was much more variable. Depth profiles covering the suboxic zone showed that the four groups of anammox-type sequences were expressed consistently in the lower suboxic zone, and were consistent with anammox 16S rDNA gene profiles. By contrast, denitrifier-type nirS sequence groups were mixed; half of the groups exhibited consistent expression in the lower suboxic zone, while others varied between season and depth. Co-occurrence of both anammox and denitrifier expression was common and ongoing. Both types of transcripts were also found in samples with low concentrations of sulfide ( >2 ?M. 6 major groups of denitrifier-type nirS transcripts were identified, making these transcripts more diverse than previous DNA clone libraries. Several groups of denitrifier-type nirS transcripts were closely related to sequences from the Baltic Sea. An increase in denitrifier-type nirS transcript diversity and depth range in October 2007 corresponded to an increase in mixed layer net community productivity as measured by O2/Ar gas ratios, as well as to an increase in N2 concentrations in the upper suboxic zone. Taken together, the variations in expression patterns between anammox and denitrification provide one explanation as to how near instantaneous rate measurements, such as isotope spike experiments, may regularly detect anammox activity but underreport denitrification.

  15. Tillage Management and Seasonal Effects on Denitrifier Community Abundance, Gene Expression and Structure over Winter.

    Science.gov (United States)

    Tatti, Enrico; Goyer, Claudia; Burton, David L; Wertz, Sophie; Zebarth, Bernie J; Chantigny, Martin; Filion, Martin

    2015-10-01

    Tillage effects on denitrifier communities and nitrous oxide (N2O) emissions were mainly studied during the growing season. There is limited information for the non-growing season, especially in northern countries where winter has prolonged periods with sub-zero temperatures. The abundance and structure of the denitrifier community, denitrification gene expression and N2O emissions in fields under long-term tillage regimes [no-tillage (NT) vs conventional tillage (CT)] were assessed during two consecutive winters. NT exerted a positive effect on nirK and nosZ denitrifier abundance in both winters compared to CT. Moreover, the two contrasting managements had an opposite influence on nirK and nirS RNA/DNA ratios. Tillage management resulted in different denitrifier community structures during both winters. Seasonal changes were observed in the abundance and the structure of denitrifiers. Interestingly, the RNA/DNA ratios were greater in the coldest months for nirK, nirS and nosZ. N2O emissions were not influenced by management but changed over time with two orders of magnitude increase in the coldest month of both winters. In winter of 2009-2010, emissions were mainly as N2O, whereas in 2010-2011, when soil temperatures were milder due to persistent snow cover, most emissions were as dinitrogen. Results indicated that tillage management during the growing season induced differences in denitrifier community structure that persisted during winter. However, management did not affect the active cold-adapted community structure. PMID:25851442

  16. Effect of pyrene on denitrification activity and abundance and composition of denitrifying community in an agricultural soil

    Energy Technology Data Exchange (ETDEWEB)

    Guo Guangxia; Deng Huan; Qiao Min; Mu Yujing [State Key Lab of Regional and Urban Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Zhu Yongguan, E-mail: ygzhu@rcees.ac.cn [State Key Lab of Regional and Urban Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021 (China)

    2011-07-15

    Toxicity of pyrene on the denitrifiers was studied by spiking an agricultural soil with pyrene to a series of concentrations (0-500 mg kg{sup -1}) followed by dose-response and dynamic incubation experiments. Results showed a positive correlation between potential denitrification activity and copy numbers of denitrifying functional genes (nirK, nirS and nosZ), and were both negatively correlated with pyrene concentrations. Based on the comparison of EC{sub 50} values, denitrifiers harboring nirK, nirS or nosZ gene were more sensitive than denitrification activity, and denitrifiers harboring nirS gene were more sensitive than that harboring nirK or nosZ genes. Seven days after spiking with EC{sub 50} concentration of pyrene, denitrifiers diversity decreased and community composition changed in comparison with the control. Phylogenetic analyses of three genes showed that the addition of pyrene increased the proportion of Bradyrhizobiaceae, Rhodospirillales, Burkholderiales and Pseudomonadales. Some species belonging to these groups were reported to be able to degrade PAHs. - Highlights: > Toxicity of pyrene on the denitrifiers was studied by spiking an agricultural soil with pyrene. > PDA was positively correlated with the abundance of denitrifiers harboring nirK, nirS or nosZ gene. > Both PDA and the abundance of denitrifiers were negatively correlated with pyrene concentrations. > Denitrifiers harboring nirk, nirS or nosZ gene are more sensitive to pyrene than PDA in soils. - Denitrifiers harboring nirK, nirS or nosZ gene are more sensitive to pyrene contamination than potential denitrification activity in soils.

  17. Effect of pyrene on denitrification activity and abundance and composition of denitrifying community in an agricultural soil

    International Nuclear Information System (INIS)

    Toxicity of pyrene on the denitrifiers was studied by spiking an agricultural soil with pyrene to a series of concentrations (0-500 mg kg-1) followed by dose-response and dynamic incubation experiments. Results showed a positive correlation between potential denitrification activity and copy numbers of denitrifying functional genes (nirK, nirS and nosZ), and were both negatively correlated with pyrene concentrations. Based on the comparison of EC50 values, denitrifiers harboring nirK, nirS or nosZ gene were more sensitive than denitrification activity, and denitrifiers harboring nirS gene were more sensitive than that harboring nirK or nosZ genes. Seven days after spiking with EC50 concentration of pyrene, denitrifiers diversity decreased and community composition changed in comparison with the control. Phylogenetic analyses of three genes showed that the addition of pyrene increased the proportion of Bradyrhizobiaceae, Rhodospirillales, Burkholderiales and Pseudomonadales. Some species belonging to these groups were reported to be able to degrade PAHs. - Highlights: ? Toxicity of pyrene on the denitrifiers was studied by spiking an agricultural soil with pyrene. ? PDA was positively correlated with the abundance of denitrifiers harboring nirK, nirS or nosZ gene. ? Both PDA and the abundance of denitrifiers were negatively correlated with pyrene concentrations. ? Denitrifiers harboring nirk, nirS or nosZ gene are more sensitive to pyrene than PDA in soils. - Denitrifiers harboring nirK, nirS or nosZ gene are more sensitive to pyrene contamination than potential denitrification activity in soils.

  18. Comparison of alcohol shock enrichment and selective enrichment for the isolation of Clostridium difficile.

    OpenAIRE

    Riley, T. V.; Brazier, J. S.; Hassan, H.; Williams, K; Phillips, K D

    1987-01-01

    Two enrichment methods were compared for their ability to recover Clostridium difficile from stool samples. One method used selective enrichment in an antibiotic-containing broth followed by detection with a latex particle agglutination (LPA) reagent. The other used enrichment in a non-selective broth following treatment of the specimen with alcohol. With clinical specimens enrichment culture was significantly more successful at detecting C. difficile than direct plating. Alcohol shock enrich...

  19. Use of starter cultures of lactic acid bacteria and yeasts as inoculum enrichment for the production of gowé, a sour beverage from Benin

    DEFF Research Database (Denmark)

    Vieira-Dalodé, G.; Madodé, Y.E.; Hounhouigan, J.; Jespersen, Lene; Jakobsen, Mogens

    2008-01-01

    Lactobacillus fermentum, Weissella confusa, Kluyveromyces marxianus and Pichia anomala, previously isolated during natural fermentation of traditional gowé, were tested as inoculum enrichment for controlled fermentation of gowé. The final product was subjected to chemical analysis and sensory eva...

  20. Pyruvic oxime nitrification and copper and nickel resistance by a Cupriavidus pauculus, an active heterotrophic nitrifier-denitrifier.

    Science.gov (United States)

    Ramirez, Miguel; Obrzydowski, Jennifer; Ayers, Mary; Virparia, Sonia; Wang, Meijing; Stefan, Kurtis; Linchangco, Richard; Castignetti, Domenic

    2014-01-01

    Heterotrophic nitrifiers synthesize nitrogenous gasses when nitrifying ammonium ion. A Cupriavidus pauculus, previously thought an Alcaligenes sp. and noted as an active heterotrophic nitrifier-denitrifier, was examined for its ability to produce nitrogen gas (N2) and nitrous oxide (N2O) while heterotrophically nitrifying the organic substrate pyruvic oxime [CH3-C(NOH)-COOH]. Neither N2 nor N2O were produced. Nucleotide and phylogenetic analyses indicated that the organism is a member of a genus (Cupriavidus) known for its resistance to metals and its metabolism of xenobiotics. The microbe (a Cupriavidus pauculus designated as C. pauculus strain UM1) was examined for its ability to perform heterotrophic nitrification in the presence of Cu(2+) and Ni(2+) and to metabolize the xenobiotic phenol. The bacterium heterotrophically nitrified well when either 1?mM Cu(2+) or 0.5?mM Ni(2+) was present in either enriched or minimal medium. The organism also used phenol as a sole carbon source in either the presence or absence of 1?mM Cu(2+) or 0.5?mM Ni(2+). The ability of this isolate to perform a number of different metabolisms, its noteworthy resistance to copper and nickel, and its potential use as a bioremediation agent are discussed. PMID:25580463

  1. Environmental evaluation of coexistence of denitrifying anaerobic methane-oxidizing archaea and bacteria in a paddy field.

    Science.gov (United States)

    Ding, Jing; Fu, Liang; Ding, Zhao-Wei; Lu, Yong-Ze; Cheng, Shuk H; Zeng, Raymond J

    2016-01-01

    The nitrate-dependent denitrifying anaerobic methane oxidation (DAMO) process, which is metabolized together by anaerobic methanotrophic archaea and NC10 phylum bacteria, is expected to be important for the global carbon and nitrogen cycles. However, there are little studies about the existence of this process and the functional microbes in environments. Therefore, the coexistence of DAMO archaea and bacteria in a paddy field was evaluated in this study. Next-generation sequencing showed that the two orders, Methanosarcinales and Nitrospirales, to which DAMO archaea and DAMO bacteria belong, were detected in the four soil samples. Then the in vitro experiments demonstrated both of nitrite- and nitrate-dependent DAMO activities, which confirmed the coexistence of DAMO archaea and DAMO bacteria. It was the first report about the coexistence of DAMO archaea and bacteria in a paddy field. Furthermore, anammox bacteria were detected in two of the four samples. The in vitro experiments did not show anammox activity in the initial period but showed low anammox activity after 20 days' enrichment. These results implicated that anammox bacteria may coexist with DAMO microorganisms in this field, but at a very low percentage. PMID:26394860

  2. Job Enrichment

    Science.gov (United States)

    Sanders, Rick

    1970-01-01

    Job enrichment means giving people more decision-making power, more responsibility, more grasp of the totality of the job, and a sense of their own importance in the company. This article presents evidence of the successful working of this approach (Donnelly Mirrors), and the lack of success with an opposing approach (General Motors). (NL)

  3. Mapping spatial patterns of denitrifiers for bridging community ecology and microbial processes along environmental gradients.

    Czech Academy of Sciences Publication Activity Database

    Philippot, L.; ?uhel, Ji?í; Saby, N.P.A.; Chéneby, D.; Chro?áková, Alica; Bru, D.; Arrouays, D.; Martin-Laurent, F.; Šimek, Miloslav

    Uppsala : Swedish University of Agricultural Sciences, 2009. s. 110. [BAGECO 10. Bacterial Genetics and Ecology - Coexisting on a Changing Planet. 15.06.2009-19.06.2009, Uppsala] Institutional research plan: CEZ:AV0Z60660521 Keywords : spatial patterns * denitrifiers * microbial processes Subject RIV: EH - Ecology, Behaviour

  4. Cattle activities affect abundance and activity of nitrifying and denitrifying microbial communities in upland soil.

    Czech Academy of Sciences Publication Activity Database

    Chro?áková, Alica; Radl, V.; ?uhel, Ji?í; Gattinger, A.; Šimek, Miloslav; Elhottová, Dana; Schloter, M.

    Uppsala : Swedish University of Agriculture Sciences, 2007. [Achievements of COST 856. Denitrification and related aspects. Final meeting of the ESF COST Action 856 /14./. 05.12.2007-08.12.2007, Uppsala] Institutional research plan: CEZ:AV0Z60660521 Keywords : cattle activities * nitrifying and denitrifying microbial communities * upland soil Subject RIV: EH - Ecology, Behaviour

  5. Post-cold-storage conditioning time affects soil denitrifying enzyme activity

    DEFF Research Database (Denmark)

    Chirinda, Ngonidzashe; Olesen, Jørgen Eivind; Porter, John Roy

    2011-01-01

    Soil denitrifying enzyme activity (DEA) is often assessed after cold storage. Previous studies using the short-term acetylene inhibition method have not considered conditioning time (post-cold-storage warm-up time prior to soil analysis) as a factor influencing results. We observed fluctuations in...

  6. Post cold-storage conditioning time affects soil denitrifying enzyme activity

    DEFF Research Database (Denmark)

    Chirinda, Ngoni; Olesen, Jørgen E; Porter, John R.

    2011-01-01

    Soil denitrifying enzyme activity (DEA) is often assessed after cold storage. Previous studies using the short-term acetylene inhibition method have not considered conditioning time (post-cold-storage warm-up time prior to soil analysis) as a factor influencing results. We observed fluctuations in DEA following cold storage, suggesting a need to consider conditioning time when planning and interpreting results.

  7. Uranium enrichment

    International Nuclear Information System (INIS)

    This paper reports that in 1990 the Department of Energy began a two-year project to illustrate the technical and economic feasibility of a new uranium enrichment technology-the atomic vapor laser isotope separation (AVLIS) process. GAO believes that completing the AVLIS demonstration project will provide valuable information about the technical viability and cost of building an AVLIS plant and will keep future plant construction options open. However, Congress should be aware that DOE still needs to adequately demonstrate AVLIS with full-scale equipment and develop convincing cost projects. Program activities, such as the plant-licensing process, that must be completed before a plant is built, could take many years. Further, an updated and expanded uranium enrichment analysis will be needed before any decision is made about building an AVLIS plant. GAO, which has long supported legislation that would restructure DOE's uranium enrichment program as a government corporation, encourages DOE's goal of transferring AVLIS to the corporation. This could reduce the government's financial risk and help ensure that the decision to build an AVLIS plant is based on commercial concerns. DOE, however, has no alternative plans should the government corporation not be formed. Further, by curtailing a planned public access program, which would have given private firms an opportunity to learn about the technology during the demonstration project, DOE may limit its ability to transfer AVLIS to the private sector

  8. Self-protected nitrate reducing culture for intrinsic repair of concrete cracks

    Science.gov (United States)

    Er?an, Yusuf Ç.; Gruyaert, Elke; Louis, Ghislain; Lors, Christine; De Belie, Nele; Boon, Nico

    2015-01-01

    Attentive monitoring and regular repair of concrete cracks are necessary to avoid further durability problems. As an alternative to current maintenance methods, intrinsic repair systems which enable self-healing of cracks have been investigated. Exploiting microbial induced CaCO3 precipitation (MICP) using (protected) axenic cultures is one of the proposed methods. Yet, only a few of the suggested healing agents were economically feasible for in situ application. This study presents a NO3? reducing self-protected enrichment culture as a self-healing additive for concrete. Concrete admixtures Ca(NO3)2 and Ca(HCOO)2 were used as nutrients. The enrichment culture, grown as granules (0.5–2 mm) consisting of 70% biomass and 30% inorganic salts were added into mortar without any additional protection. Upon 28 days curing, mortar specimens were subjected to direct tensile load and multiple cracks (0.1–0.6 mm) were achieved. Cracked specimens were immersed in water for 28 days and effective crack closure up to 0.5 mm crack width was achieved through calcite precipitation. Microbial activity during crack healing was monitored through weekly NOx analysis which revealed that 92 ± 2% of the available NO3? was consumed. Another set of specimens were cracked after 6 months curing, thus the effect of curing time on healing efficiency was investigated, and mineral formation at the inner crack surfaces was observed, resulting in 70% less capillary water absorption compared to healed control specimens. In conclusion, enriched mixed denitrifying cultures structured in self-protecting granules are very promising strategies to enhance microbial self-healing. PMID:26583015

  9. Multiplex Real-Time PCR Assays for Screening of Shiga Toxin 1 and 2 Genes, Including All Known Subtypes, and Escherichia coli O26-, O111-, and O157-Specific Genes in Beef and Sprout Enrichment Cultures.

    Science.gov (United States)

    Harada, Tetsuya; Iguchi, Atsushi; Iyoda, Sunao; Seto, Kazuko; Taguchi, Masumi; Kumeda, Yuko

    2015-10-01

    Shiga toxin family members have recently been classified using a new nomenclature into three Stx1 subtypes (Stx1a, Stx1c, and Stx1d) and seven Stx2 subtypes (Stx2a, Stx2b, Stx2c, Stx2d, Stx2e, Stx2f, and Stx2g). To develop screening methods for Stx genes, including all of these subtype genes, and Escherichia coli O26-, O111-, and O157-specific genes in laboratory investigations of Shiga toxin-producing E. coli (STEC) foodborne cases, we developed multiplex real-time PCR assays and evaluated their specificity and quantitative accuracy using STEC and non-STEC isolates, recombinant plasmids, and food enrichment cultures and by performing STEC spiking experiments with beef and sprout enrichment cultures. In addition, we evaluated the relationship between the recovery rates of the target strains by direct plating and immunomagnetic separation and the cycle threshold (CT) values of the real-time PCR assays for the Stx subtypes and STEC O26, O111, and O157 serogroups. All three stx1- and seven stx2-subtype genes were detected by real-time PCR with high sensitivity and specificity, and the quantitative accuracy of this assay was confirmed using control plasmids and STEC spiking experiments. The results of the STEC spiking experiments suggest that it is not routinely possible to isolate STEC from enrichment cultures with real-time PCR CT values greater than 30 by direct plating on MacConkey agar, although highly selective media and immunomagnetic beads were able to isolate the inoculated strains from the enrichment cultures. These data suggest that CT values obtained from the highly quantitative real-time PCR assays developed in this study provide useful information to develop effective isolation strategies for STEC from food samples. The real-time PCR assays developed here are expected to aid in investigations of infections or outbreaks caused by STEC harboring any of the stx-subtype genes in the new Stx nomenclature, as well as STEC O26, O111, and O157. PMID:26408128

  10. cultural

    Directory of Open Access Journals (Sweden)

    Irene Kreutz

    2006-01-01

    Full Text Available Es un estudio cualitativo que adoptó como referencial teorico-motodológico la antropología y la etnografía. Presenta las experiencias vivenciadas por mujeres de una comunidad en el proceso salud-enfermedad, con el objetivo de comprender los determinantes sócio-culturales e históricos de las prácticas de prevención y tratamiento adoptados por el grupo cultural por medio de la entrevista semi-estructurada. Los temas que emergieron fueron: la relación entre la alimentación y lo proceso salud-enfermedad, las relaciones con el sistema de salud oficial y el proceso salud-enfermedad y lo sobrenatural. Los dados revelaron que los moradores de la comunidad investigada tienen un modo particular de explicar sus procedimientos terapéuticos. Consideramos que es papel de los profesionales de la salud en sus prácticas, la adopción de abordajes o enfoques que consideren al individuo en su dimensión sócio-cultural e histórica, considerando la enorme diversidad cultural en nuestro país.

  11. RELATIONSHIP BETWEEN THE CONCENTRATION OF DENITRIFIERS AND PSEUDOMONAS SPP. IN SOILS: IMPLICATIONS FOR BTX BIOREMEDIATION (R823420)

    Science.gov (United States)

    Aquifer microcosms were used to investigate the effect of stimulating denitrification on microbial population shifts and BTX degradation potential. Selective pressurefor facultative denitrifiers was applied to a treatment set by feeding acetate and nitrate, and cycling electr...

  12. Simultaneous removal of sulfide, nitrate and acetate under denitrifying sulfide removal condition: Modeling and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Xijun; Chen, Chuan; Wang, Aijie; Guo, Wanqian; Zhou, Xu [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Lee, Duu-Jong, E-mail: djlee@ntu.edu.tw [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan (China); Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Ren, Nanqi, E-mail: rnq@hit.edu.cn [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090 (China); Chang, Jo-Shu [Research Center for Energy Technology and Strategy, National Cheng Kung University, Tainan, Taiwan (China)

    2014-01-15

    Graphical abstract: Model evaluation applied to case study 1: (A-G) S{sup 2?}, NO{sub 3}{sup ?}-N, NO{sub 2}{sup ?}-N, and Ac{sup ?}-C profiles under initial sulfide concentrations of 156.2 (A), 539 (B), 964 (C), 1490 (D), 342.7 (E), 718 (F), and 1140.7 (G) mg L{sup ?1}. The solid line represents simulated result and scatter represents experimental result. -- Highlights: • This work developed a mathematical model for DSR process. • Kinetics of sulfur–nitrogen–carbon and interactions between denitrifiers were studied. • Kinetic parameters of the model were estimated via data fitting. • The model described kinetic behaviors of DSR processes over wide parametric range. -- Abstract: Simultaneous removal of sulfide (S{sup 2?}), nitrate (NO{sub 3}{sup ?}) and acetate (Ac{sup ?}) under denitrifying sulfide removal process (DSR) is a novel biological wastewater treatment process. This work developed a mathematical model to describe the kinetic behavior of sulfur–nitrogen–carbon and interactions between autotrophic denitrifiers and heterotrophic denitrifiers. The kinetic parameters of the model were estimated via data fitting considering the effects of initial S{sup 2?} concentration, S{sup 2?}/NO{sub 3}{sup ?}-N ratio and Ac{sup ?}-C/NO{sub 3}{sup ?}-N ratio. Simulation supported that the heterotrophic denitratation step (NO{sub 3}{sup ?} reduction to NO{sub 2}{sup ?}) was inhibited by S{sup 2?} compared with the denitritation step (NO{sub 2}{sup ?} reduction to N{sub 2}). Also, the S{sup 2?} oxidation by autotrophic denitrifiers was shown two times lower in rate with NO{sub 2}{sup ?} as electron acceptor than that with NO{sub 3}{sup ?} as electron acceptor. NO{sub 3}{sup ?} reduction by autotrophic denitrifiers occurs 3–10 times slower when S{sup 0} participates as final electron donor compared to the S{sup 2?}-driven pathway. Model simulation on continuous-flow DSR reactor suggested that the adjustment of hydraulic retention time is an efficient way to make the reactor tolerating high S{sup 2?} loadings. The proposed model properly described the kinetic behaviors of DSR processes over wide parametric ranges and which can offer engineers with basis to optimize bioreactor operation to improve the treatment capacity.

  13. Uranium enrichment policies

    International Nuclear Information System (INIS)

    A review of U enrichment policies is presented. Discussions are included on uranium resource assessment, uranium enrichment activities, DOE enrichment plants, tails assay, DOE natural uranium stockpile, DOE enrichment services, and nuclear fuel assurances

  14. Non-cultured adipose-derived CD45(-) side population cells are enriched for progenitors that give rise to myofibres in vivo

    DEFF Research Database (Denmark)

    Andersen, Ditte C; Schrøder, Henrik D; Jensen, Charlotte H

    2008-01-01

    Side population (SP) cells are highly able to exclude the Hoechst 33342 dye through membrane transporters, a feature associated with cell immaturity and therefore proposed as a marker of stem cells. Herein we demonstrate that the adipose tissue derived stromal vascular fraction (SVF) contains a novel population of non-haematopoietic "side population" (SPCD45(-)) cells. Simultaneous qRT-PCR of 64 genes revealed that the freshly isolated SPCD45(-) was highly enriched for cells expressing genes rel...

  15. Denitrification potential under different fertilization regimes is closely coupled with changes in the denitrifying community in a black soil.

    Science.gov (United States)

    Yin, Chang; Fan, Fenliang; Song, Alin; Cui, Peiyuan; Li, Tingqiang; Liang, Yongchao

    2015-07-01

    Preferable inorganic fertilization over the last decades has led to fertility degradation of black soil in Northeast China. However, how fertilization regimes impact denitrification and its related bacterial community in this soil type is still unclear. Here, taking advantage of a suit of molecular ecological tools in combination of assaying the potential denitrification (DP), we explored the variation of activity, community structure, and abundance of nirS and nirK denitrifiers under four different fertilization regimes, namely no fertilization control (N0M0), organic pig manure (N0M1), inorganic fertilization (N1M0), and combination of inorganic fertilizer and pig manure (N1M1). The results indicated that organic fertilization increased DP, but inorganic fertilization had no impacts. The increase of DP was mirrored by the shift of nirS denitrifiers' community structure but not by that of nirK denitrifiers'. Furthermore, the change of DP coincided with the variation of abundances of both denitrifiers. Shifts of community structure and abundance of nirS and nirK denitrifiers were correlated with the change of soil pH, total nitrogen (TN), organic matter (OM), C:P, total phosphorus (TP), and available phosphorus (Olsen P). Our results suggest that the change of DP under these four fertilization regimes was closely related to the shift of denitrifying bacteria communities resulting from the variation of properties in the black soil tested. PMID:25715781

  16. Nitrous oxide reductase (nosZ) gene-specific PCR primers for detection of denitrifiers and three nosZ genes from marine sediments.

    Science.gov (United States)

    Scala, D J; Kerkhof, L J

    1998-05-01

    Two PCR primer sets for the nitrous oxide reductase gene (nosZ) were developed. The initial primers were based on three sequences in GenBank and used to amplify nosZ from continental shelf sediments and from two denitrifiers in culture, Thiosphaera pantotropha and Pseudomonas denitrificans. Three unique marine sediment nosZ genes were identified and sequenced. The marine nosZ genes were most closely related to the nosZ genes of Paracoccus denitrificans or to Rhizobium meliloti. Alignment of all nosZ sequences currently available (n = 10) facilitated redesign of the PCR primers. Three new primer sets which amplify 1100 bp, 900 bp and 250 bp regions of the nosZ gene were designed and tested. The new primers robustly amplified nosZ fragments from samples in which the initial nosZ primers were only marginally successful. PMID:9595664

  17. Relative rates of nitric oxide and nitrous oxide production by nitrifiers, denitrifiers, and nitrate respirers

    Science.gov (United States)

    Anderson, I. C.; Levine, J. S.

    1986-01-01

    An account is given of the atmospheric chemical and photochemical effects of biogenic nitric and nitrous oxide emissions. The magnitude of the biogenic emission of NO is noted to remain uncertain. Possible soil sources of NO and N2O encompass nitrification by autotropic and heterotropic nitrifiers, denitrification by nitrifiers and denitrifiers, nitrate respiration by fermenters, and chemodenitrification. Oxygen availability is the primary determinant of these organisms' relative rates of activity. The characteristics of this major influence are presently investigated in light of the effect of oxygen partial pressure on NO and N2O production by a wide variety of common soil-nitrifying, denitrifying, and nitrate-respiring bacteria under laboratory conditions. The results obtained indicate that aerobic soils are primary sources only when there is sufficient moisture to furnish anaerobic microsites for denitrification.

  18. A denitrifying bacterium from the deep sea at 11,000-m depth.

    Science.gov (United States)

    Tamegai, H; Li, L; Masui, N; Kato, C

    1997-11-01

    The denitrifying bacterium strain MT-1 was isolated from the mud of the Mariana Trench. The optimal temperature and pressure for growth of this bacterium were found to be 30 degrees C and 0.1 MPa, respectively. However, it showed greater tolerance to low temperature (4 degrees C) and high hydrostatic pressure (50 MPa) as compared with denitrifiers obtained from land. From the results, it can be said that this organism is adapted to the environment of the deep sea. Strain MT-1 was shown to belong to the genus Pseudomonas by analysis of its 16S rDNA. The cytochrome contents of the bacterium were similar to those of Ps. stutzeri in spectrophotometric studies. PMID:9680302

  19. Anaerobic toluene oxidation to benzyl alcohol and benzaldehyde in a denitrifying Pseudomonas strain.

    OpenAIRE

    Altenschmidt, U; Fuchs, G.

    1992-01-01

    The denitrifying Pseudomonas strain K172 was grown with a generation time of 6 h to a cell density of 0.4 g (dry weight) per liter with toluene and nitrate as substrates. We found that anaerobic cell suspensions oxidize [14C]toluene first to [14C]benzyl alcohol and subsequently to [14C]benzaldehyde. This proves that the methyl group of toluene is oxidized without molecular oxygen to a hydroxymethyl group.

  20. Localization of the cytochrome cd1 and copper nitrite reductases in denitrifying bacteria.

    OpenAIRE

    Coyne, M S; Arunakumari, A; Pankratz, H S; Tiedje, J. M.

    1990-01-01

    The locations of cytochrome cd1 nitrite reductases in Pseudomonas aeruginosa and Pseudomonas fluorescens and copper nitrite reductases in Achromobacter cycloclastes and Achromobacter xylosoxidans were identified. Immunogold labeling with colloidal-gold probes showed that the nitrite reductases were synthesized exclusively in anaerobically grown (denitrifying) cells. Little immunogold label occurred in the cytoplasm of these four strains; most was found in the periplasmic space or was associat...

  1. Evaluation of the microbial diversity of denitrifying bacteria in batch reactor

    OpenAIRE

    S. I. Maintinguer; I. K. Sakamoto; M. A. T. Adorno; M. B. A. Varesche

    2013-01-01

    Microbial communities in an industrial activated sludge plant may contribute to the denitrification process, but the information on the microorganisms present in denitrifying reactors is still scarce. Removal of inorganic nitrogen compounds can be accomplished by the addition of carbon sources to the biological process of denitrification. Ethanol is an economically viable alternative as a carbon source in tropical countries like Brazil, with large-scale production from sugarcane. This paper r...

  2. Sediment denitrifier community composition and nirS gene expression investigated with functional gene microarrays

    DEFF Research Database (Denmark)

    Francis, C.A.; Jackson, G.A.; Ward, B.B.; Bülow, Steffen

    2008-01-01

    A functional gene microarray was used to investigate denitrifier community composition and nitrite reductase (nirS) gene expression in sediments along the estuarine gradient in Chesapeake Bay, USA. The nirS oligonucleotide probe set was designed to represent a sequence database containing 539 Chesapeake Bay clones, as well as sequences from many other environments. Greatest nirS diversity was detected at the freshwater station at the head of the bay and least diversity at the higher salinity sta...

  3. Coexistence of nitrifying, anammox and denitrifying bacteria in a sequencing batch reactor

    OpenAIRE

    MichelaLangone; JiaYan

    2014-01-01

    Elevated nitrogen removal efficiencies from ammonium-rich wastewaters have been demonstrated by several applications, that combine nitritation and anammox processes. Denitrification will occur simultaneously when organic carbon is also present. In this study, the activity of aerobic ammonia oxidizing, anammox and denitrifying bacteria in a full scale Sequencing Batch Reactor, treating digester supernatants, was studied by means of batch-assays. AOB and anammox activities were maximum at pH of...

  4. Denitrifying microbial consortium in pasture soil is influenced by the intensity of cattle-induced stress.

    Czech Academy of Sciences Publication Activity Database

    ?uhel, Ji?í; Šimek, Miloslav

    Nijmegen : Radboud University Nijmegen, 2006. s. 38. [ COST Action 856, Ecological Aspects of Denitrification, with Emphasis on Agriculture. Management Committee Meeting & Workshop, New developments in the N-cycle reactions in the first decade of the 21st century. 09.03.2006-11.03.2006, Nijmegen] Institutional research plan: CEZ:AV0Z60660521 Keywords : denitrifying microbial consortium * pasture soil * intensity of cattle-induced stress Subject RIV: EH - Ecology, Behaviour

  5. Impact of plant identity, diversity and composition on diversity, composition and function of nirK-type denitrifying microorganisms in temperate grassland soil

    OpenAIRE

    Bremer, Christina

    2007-01-01

    The impact of plant species, the number of plant species (diversity) and the composition of plant species on nirK-type denitrifying microorganisms in soil was studied. NirK encodes the enzyme nitrite reductase which is the key enzyme for dissimilatory nitrate reduction. As a measure for denitrifier function, net and gross dinitrogenoxide (N2O) production rates and denitrifier enzyme activity were determined. Plant identity, divers...

  6. Abundance, composition and activity of denitrifier communities in metal polluted paddy soils

    Science.gov (United States)

    Liu, Yuan; Liu, Yongzhuo; Zhou, Huimin; Li, Lianqing; Zheng, Jinwei; Zhang, Xuhui; Zheng, Jufeng; Pan, Genxing

    2016-01-01

    Denitrification is one of the most important soil microbial processes leading to the production of nitrous oxide (N2O). The potential changes with metal pollution in soil microbial community for N2O production and reduction are not well addressed. In this study, topsoil samples were collected both from polluted and non-polluted rice paddy fields and denitrifier communities were characterized with molecular fingerprinting procedures. All the retrieved nirK sequences could be grouped into neither α- nor β- proteobacteria, while most of the nosZ sequences were affiliated with α-proteobacteria. The abundances of the nirK and nosZ genes were reduced significantly in the two polluted soils. Thus, metal pollution markedly affected composition of both nirK and nosZ denitrifiers. While the total denitrifying activity and N2O production rate were both reduced under heavy metal pollution of the two sites, the N2O reduction rate showed no significant change. These findings suggest that N2O production activity could be sensitive to heavy metal pollution, which could potentially lead to a decrease in N2O emission in polluted paddies. Therefore, metal pollution could have potential impacts on soil N transformation and thus on N2O emission from paddy soils.

  7. Sediment denitrifier community composition and nirS gene expression investigated with functional gene microarrays

    DEFF Research Database (Denmark)

    Francis, C.A.; Jackson, G.A.

    2008-01-01

    A functional gene microarray was used to investigate denitrifier community composition and nitrite reductase (nirS) gene expression in sediments along the estuarine gradient in Chesapeake Bay, USA. The nirS oligonucleotide probe set was designed to represent a sequence database containing 539 Chesapeake Bay clones, as well as sequences from many other environments. Greatest nirS diversity was detected at the freshwater station at the head of the bay and least diversity at the higher salinity station near the mouth of the Bay. The most common OTUs from the sequence database were detected on the array with high signal strength in most samples. One of the most abundant OTUs, CB2-S-138, was identified as dominant at the mid-bay site by both microarray and quantitative PCR assays, but it comprised a much smaller fraction of the assemblage in the north and south bay samples. cDNA (transcribed from total RNA extracts) targets were hybridized to the same array to compare the profiles of community composition at the DNA (relative abundance) and mRNA (gene expression) levels. Only the three dominant denitrifying groups (in terms of relative strength of DNA hybridization signal) were detected at the mRNA level. These results suggest that the most actively denitrifying groups are responsible for most nirS expression as well Udgivelsesdato: 2008/11

  8. Abundance, composition and activity of denitrifier communities in metal polluted paddy soils

    Science.gov (United States)

    Liu, Yuan; Liu, Yongzhuo; Zhou, Huimin; Li, Lianqing; Zheng, Jinwei; Zhang, Xuhui; Zheng, Jufeng; Pan, Genxing

    2016-01-01

    Denitrification is one of the most important soil microbial processes leading to the production of nitrous oxide (N2O). The potential changes with metal pollution in soil microbial community for N2O production and reduction are not well addressed. In this study, topsoil samples were collected both from polluted and non-polluted rice paddy fields and denitrifier communities were characterized with molecular fingerprinting procedures. All the retrieved nirK sequences could be grouped into neither ?- nor ?- proteobacteria, while most of the nosZ sequences were affiliated with ?-proteobacteria. The abundances of the nirK and nosZ genes were reduced significantly in the two polluted soils. Thus, metal pollution markedly affected composition of both nirK and nosZ denitrifiers. While the total denitrifying activity and N2O production rate were both reduced under heavy metal pollution of the two sites, the N2O reduction rate showed no significant change. These findings suggest that N2O production activity could be sensitive to heavy metal pollution, which could potentially lead to a decrease in N2O emission in polluted paddies. Therefore, metal pollution could have potential impacts on soil N transformation and thus on N2O emission from paddy soils. PMID:26739424

  9. A comparative study of the bacterial community in denitrifying and traditional enhanced biological phosphorus removal processes.

    Science.gov (United States)

    Lv, Xiao-Mei; Shao, Ming-Fei; Li, Chao-Lin; Li, Ji; Gao, Xin-Lei; Sun, Fei-Yun

    2014-09-17

    Denitrifying phosphorus removal is an attractive wastewater treatment process due to its reduced carbon source demand and sludge minimization potential. Two lab-scale sequencing batch reactors (SBRs) were operated in alternating anaerobic-anoxic (A-A) or anaerobic-oxic (A-O) conditions to achieve denitrifying enhanced biological phosphate removal (EBPR) and traditional EBPR. No significant differences were observed in phosphorus removal efficiencies between A-A SBR and A-O SBR, with phosphorus removal rates being 87.9% and 89.0% respectively. The community structures in denitrifying and traditional EBPR processes were evaluated by high-throughput sequencing of the PCR-amplified partial 16S rRNA genes from each sludge. The results obtained showed that the bacterial community was more diverse in A-O sludge than in A-A sludge. Taxonomy and ?-diversity analyses indicated that a significant shift occurred in the dominant microbial community in A-A sludge compared with the seed sludge during the whole acclimation phase, while a slight fluctuation was observed in the abundance of the major taxonomies in A-O sludge. One Dechloromonas-related OTU outside the 4 known Candidatus "Accumulibacter" clades was detected as the main OTU in A-A sludge at the stationary operation, while Candidatus "Accumulibacter" dominated in A-O sludge. PMID:24964811

  10. Use of starter cultures of lactic acid bacteria and yeasts as inoculum enrichment for the production of gowé, a sour beverage from Benin

    DEFF Research Database (Denmark)

    Vieira-Dalodé, G.; Madodé, Y.E.

    2008-01-01

    Lactobacillus fermentum, Weissella confusa, Kluyveromyces marxianus and Pichia anomala, previously isolated during natural fermentation of traditional gowé, were tested as inoculum enrichment for controlled fermentation of gowé. The final product was subjected to chemical analysis and sensory evaluation. Growth of the lactic acid bacteria (LAB) and yeasts were verified by determination of colony forming units (CFU) and molecular biology techniques. A significant decrease in pH from 6.1 to 3.3, with a concomitant increase in titratable acidity (11 to 60 g/kg as lactic acid, dry weight), was observed after 24 h of fermentation when LAB was used either alone or in combination with yeasts. The LAB count increased significantly from 6.1 to 9.4 log CFU/ml, while the yeast count remained constant throughout fermentation. Repetitive-polymerase chain reaction (rep-PCR) assays performed on isolates during the fermentation confirmed the dominance of the added LAB strains. Sensory evaluation revealed that the product fermented for 7 h with L. fermentum alone or in combination with K. marxianus was as acceptable as the traditional product normally obtained after a minimum of 24 h of fermentation. Consequently, gowé can be obtained by controlled fermentation, using L. fermentum as inoculum enrichment, in a small scale industry.  

  11. Distribution of baroduric, psychrotrophic and culturable nitrifying and denitrifying bacteria in the Central Indian Basin

    Digital Repository Service at National Institute of Oceanography (India)

    LokaBharathi, P.A.; PradeepRam, A.S.; Nair, S.; Nath, B.N.; Chandramohan, D.

    minutes-76 degrees 05 minutes E, showed that nitrifying bacteria were present in layers of sediment 0-25 cm below sea floor (bsf) with maximum numbers at sub-surface layers. Their average numbers ranged from 4.0 x 10 sup(4) to 2.43 x 10 sup(8) CFU g sup(-1...

  12. Denitrifying phosphorus removal from municipal wastewater and dynamics of "Candidatus Accumulibacter" and denitrifying bacteria based on genes of ppk1, narG, nirS and nirK.

    Science.gov (United States)

    Zeng, Wei; Zhang, Jie; Wang, Anqi; Peng, Yongzhen

    2016-05-01

    Relevance of clade-level population dynamics of "Candidatus Accumulibacter" to performance of denitrifying phosphorus (P) removal from municipal wastewater was investigated. Stable denitrifying P removal in anoxic zone of continuous-flow reactor was achieved, accounting for 90% of total P removal. Clades IIC and IIF affiliated with Accumulibacter lineage were the dominant clades during denitrifying P removal, reaching 90% of ppk1 clone library. NarG gene library indicated Gamma and Beta-proteobacteria played an important role in nitrate reduction. Diversity and abundance of nirS library was much more than nirK, and thus became the main functional gene to execute nitrite reduction. Based on abundance of nirS, nirK and ppk1, the ratio of Accumulibacter capable of denitrifying P removal to total Accumulibacter was 22%. No matter whether Accumulibacter had narG gene or not, high abundance of narG at a level of 10(9)cells/(g dried-sludge) promoted nitrate reduced to nitrite, ensuring performance of denitrifying P removal. PMID:26896717

  13. Enrichment of Secondary Wastewater Sludge for Production of Hydrogen from Crude Glycerol and Comparative Evaluation of Mono-, Co- and Mixed-Culture Systems

    Directory of Open Access Journals (Sweden)

    Vinayak Laxman Pachapur

    2016-01-01

    Full Text Available Anaerobic digestion using mixed-culture with broader choice of pretreatments for hydrogen (H2 production was investigated. Pretreatment of wastewater sludge by five methods, such as heat, acid, base, microwave and chloroform was conducted using crude glycerol (CG as substrate. Results for heat treatment (100 °C for 15 min showed the highest H2 production across the pretreatment methods with 15.18 ± 0.26 mmol/L of medium at 30 °C in absence of complex media and nutrient solution. The heat-pretreated inoculum eliminated H2 consuming bacteria and produced twice as much as H2 as compared to other pretreatment methods. The fermentation conditions, such as CG concentration (1.23 to 24 g/L, percentage of inoculum size (InS (1.23% to 24% v/v along with initial pH (2.98 to 8.02 was tested using central composite design (CCD with H2 production as response parameter. The maximum H2 production of 29.43 ± 0.71 mmol/L obtained at optimum conditions of 20 g/L CG, 20% InS and pH 7. Symbiotic correlation of pH over CG and InS had a significant (p-value: 0.0011 contribution to H2 production. The mixed-culture possessed better natural acclimatization activity for degrading CG, at substrate inhibition concentration and provided efficient inoculum conditions in comparison to mono- and co-culture systems. The heat pretreatment step used across mixed-culture system is simple, cheap and industrially applicable in comparison to mono-/co-culture systems for H2 production.

  14. Enrichment of Secondary Wastewater Sludge for Production of Hydrogen from Crude Glycerol and Comparative Evaluation of Mono-, Co- and Mixed-Culture Systems.

    Science.gov (United States)

    Pachapur, Vinayak Laxman; Kutty, Prianka; Brar, Satinder Kaur; Ramirez, Antonio Avalos

    2016-01-01

    Anaerobic digestion using mixed-culture with broader choice of pretreatments for hydrogen (H?) production was investigated. Pretreatment of wastewater sludge by five methods, such as heat, acid, base, microwave and chloroform was conducted using crude glycerol (CG) as substrate. Results for heat treatment (100 °C for 15 min) showed the highest H? production across the pretreatment methods with 15.18 ± 0.26 mmol/L of medium at 30 °C in absence of complex media and nutrient solution. The heat-pretreated inoculum eliminated H? consuming bacteria and produced twice as much as H? as compared to other pretreatment methods. The fermentation conditions, such as CG concentration (1.23 to 24 g/L), percentage of inoculum size (InS) (1.23% to 24% v/v) along with initial pH (2.98 to 8.02) was tested using central composite design (CCD) with H? production as response parameter. The maximum H? production of 29.43 ± 0.71 mmol/L obtained at optimum conditions of 20 g/L CG, 20% InS and pH 7. Symbiotic correlation of pH over CG and InS had a significant (p-value: 0.0011) contribution to H? production. The mixed-culture possessed better natural acclimatization activity for degrading CG, at substrate inhibition concentration and provided efficient inoculum conditions in comparison to mono- and co-culture systems. The heat pretreatment step used across mixed-culture system is simple, cheap and industrially applicable in comparison to mono-/co-culture systems for H? production. PMID:26771607

  15. Enrichment of Secondary Wastewater Sludge for Production of Hydrogen from Crude Glycerol and Comparative Evaluation of Mono-, Co- and Mixed-Culture Systems

    Science.gov (United States)

    Pachapur, Vinayak Laxman; Kutty, Prianka; Brar, Satinder Kaur; Ramirez, Antonio Avalos

    2016-01-01

    Anaerobic digestion using mixed-culture with broader choice of pretreatments for hydrogen (H2) production was investigated. Pretreatment of wastewater sludge by five methods, such as heat, acid, base, microwave and chloroform was conducted using crude glycerol (CG) as substrate. Results for heat treatment (100 °C for 15 min) showed the highest H2 production across the pretreatment methods with 15.18 ± 0.26 mmol/L of medium at 30 °C in absence of complex media and nutrient solution. The heat-pretreated inoculum eliminated H2 consuming bacteria and produced twice as much as H2 as compared to other pretreatment methods. The fermentation conditions, such as CG concentration (1.23 to 24 g/L), percentage of inoculum size (InS) (1.23% to 24% v/v) along with initial pH (2.98 to 8.02) was tested using central composite design (CCD) with H2 production as response parameter. The maximum H2 production of 29.43 ± 0.71 mmol/L obtained at optimum conditions of 20 g/L CG, 20% InS and pH 7. Symbiotic correlation of pH over CG and InS had a significant (p-value: 0.0011) contribution to H2 production. The mixed-culture possessed better natural acclimatization activity for degrading CG, at substrate inhibition concentration and provided efficient inoculum conditions in comparison to mono- and co-culture systems. The heat pretreatment step used across mixed-culture system is simple, cheap and industrially applicable in comparison to mono-/co-culture systems for H2 production. PMID:26771607

  16. Effect of pyrene on denitrification activity and abundance and composition of denitrifying community in an agricultural soil.

    Science.gov (United States)

    Guo, Guang-Xia; Deng, Huan; Qiao, Min; Mu, Yu-Jing; Zhu, Yong-Guan

    2011-07-01

    Toxicity of pyrene on the denitrifiers was studied by spiking an agricultural soil with pyrene to a series of concentrations (0-500 mg kg(-1)) followed by dose-response and dynamic incubation experiments. Results showed a positive correlation between potential denitrification activity and copy numbers of denitrifying functional genes (nirK, nirS and nosZ), and were both negatively correlated with pyrene concentrations. Based on the comparison of EC(50) values, denitrifiers harboring nirK, nirS or nosZ gene were more sensitive than denitrification activity, and denitrifiers harboring nirS gene were more sensitive than that harboring nirK or nosZ genes. Seven days after spiking with EC(50) concentration of pyrene, denitrifiers diversity decreased and community composition changed in comparison with the control. Phylogenetic analyses of three genes showed that the addition of pyrene increased the proportion of Bradyrhizobiaceae, Rhodospirillales, Burkholderiales and Pseudomonadales. Some species belonging to these groups were reported to be able to degrade PAHs. PMID:21497968

  17. Simultaneous production of acetate and methane from glycerol by selective enrichment of hydrogenotrophic methanogens in extreme-thermophilic (70 °C) mixed culture fermentation

    International Nuclear Information System (INIS)

    Highlights: • Simultaneous production of acetate and methane from glycerol was investigated. • Acetate accounted for more than 90% of metabolites in liquid solutions. • The maximum concentration of acetate was above 13 g/L. • 93% of archaea were hydrogenotrophic methanogens. • Thermoanaerobacter was main bacterium and its percentage was 92%. - Abstract: The feasibility of simultaneous production of acetate and methane from glycerol was investigated by selective enrichment of hydrogenotrophic methanogens in an extreme-thermophilic (70 °C) fermentation. Fed-batch experiments showed acetate was produced at the concentration up to 13.0 g/L. A stable operation of the continuous stirred tank reactor (CSTR) was reached within 100 days. Acetate accounted for more than 90 w/w% of metabolites in the fermentation liquid. The yields of methane and acetate were close to the theoretical yields with 0.74–0.80 mol-methane/mol-glycerol and 0.63–0.70 mol-acetate/mol-glycerol. The obtained microbial community was characterized. Hydrogenotrophic methanogens, mainly Methanothermobacter thermautotrophicus formed 93% of the methanogenogenic community. This confirms that a high temperature (70 °C) could effectively select for hydrogenotrophic methanogenic archaea. Thermoanaerobacter spp. was the main bacterium forming 91.5% of the bacterial population. This work demonstrated the conversion of the byproduct of biodiesel production, glycerol, to acetate as a chemical and biogas for energy generation

  18. Nitrogen Removal by a Fungal Aerobic Denitrifier of Penicillium Strain

    Directory of Open Access Journals (Sweden)

    Chaocheng Zhao

    2012-01-01

    Full Text Available A kind of aerobic Penicillium that can remove ammonia, nitrite and nitrate was isolated through an improved bromothymol blue (BTB selective culture medium method in this experiment and then the nitrogen removal by the strain was detailedly investigated. The results showed that this strain was able to make use of many kinds of organic carbon compounds as sole carbon source for the removal of the three types of inorganic nitrogen compounds but the way of removal was different. Ammonia was assimilated for forming cell components such as amino acid and protein, different from which, nitrite and nitrate were eliminated by the aid of dual assimilation and denitrification. When the three types of nitrogen coexist, the removal order was as follows: ammonia>nitrite>nitrate. Type of carbon source, initial nitrogen concentration and carbon nitrogen ratio (C/N all had different effect on final solution pH, dry weight, nitrogen removal rate and removal ability of the strain. It was tested that non-polar organic carbon source containing -CH3 group like sucrose was inclined to be used by the strain. When sucrose was carbon source, the optimum C/N of ammonia, nitrite and nitrate removal were separate 4-6, 8-12 and 12-16. In addition, it was demonstrated with calculation that the removal abilities of the above mentioned three nitrogen of the strain were about 50, 60 and 90 mg g-1 respectively, showing its tremendous capability of nitrogen removal.

  19. Nitrogen Removal Characteristics of a Newly Isolated Indigenous Aerobic Denitrifier from Oligotrophic Drinking Water Reservoir, Zoogloea sp. N299

    Directory of Open Access Journals (Sweden)

    Ting-Lin Huang

    2015-05-01

    Full Text Available Nitrogen is considered to be one of the most widespread pollutants leading to eutrophication of freshwater ecosystems, especially in drinking water reservoirs. In this study, an oligotrophic aerobic denitrifier was isolated from drinking water reservoir sediment. Nitrogen removal performance was explored. The strain was identified by 16S rRNA gene sequence analysis as Zoogloea sp. N299. This species exhibits a periplasmic nitrate reductase gene (napA. Its specific growth rate was 0.22 h?1. Obvious denitrification and perfect nitrogen removal performances occurred when cultured in nitrate and nitrite mediums, at rates of 75.53% ± 1.69% and 58.65% ± 0.61%, respectively. The ammonia removal rate reached 44.12% ± 1.61% in ammonia medium. Zoogloea sp. N299 was inoculated into sterilized and unsterilized reservoir source waters with a dissolved oxygen level of 5–9 mg/L, pH 8–9, and C/N 1.14:1. The total nitrogen removal rate reached 46.41% ± 3.17% (sterilized and 44.88% ± 4.31% (unsterilized. The cell optical density suggested the strain could survive in oligotrophic drinking water reservoir water conditions and perform nitrogen removal. Sodium acetate was the most favorable carbon source for nitrogen removal by strain N299 (p < 0.05. High C/N was beneficial for nitrate reduction (p < 0.05. The nitrate removal efficiencies showed no significant differences among the tested inoculums dosage (p > 0.05. Furthermore, strain N299 could efficiently remove nitrate at neutral and slightly alkaline and low temperature conditions. These results, therefore, demonstrate that Zoogloea sp. N299 has high removal characteristics, and can be used as a nitrogen removal microbial inoculum with simultaneous aerobic nitrification and denitrification in a micro-polluted reservoir water ecosystem.

  20. Effect of CO2 enrichment and high photosynthetic photon flux densities (PPFD) on rubisco and PEP-case activities of in vitro cultured strawberry plants

    International Nuclear Information System (INIS)

    Standard growing conditions in vitro (low light and CO2) are not conducive to autotrophy. An experiment was conducted to improve photosynthesis in vitro in the hope of increasing survival in acclimatization. A factorial experiment was elaborated where CO2 and PPFD were supplied to in vitro cultured strawberry plants in the rooting stage. Activities of carboxylating enzymes were determined after 4 weeks of culture. The activities of non-activated and activated rubisco and PEP-Case were measured after extraction of the enzymes and a reaction with NaH14CO3 followed by scintillation counting spectroscopy. High CO2 concentration significantly increased net assimilation rates (NAR) by 165% over the control for both 1650 and 3000 ppm CO2. High PPFD only increased NAR by 12 and 35% for 150 and 250 ?mol·m-2·s-1 respectively over the control. Plants grown at 3000 ppm CO2 had the highest level of chlorophyll/g FW with 97% more than the control. The activity of PEP-Case was the highest at high light levels and high CO2 with rates of 1.65 for 1650 ppm versus 1.22 mmol CO2 mg-1 chl. h-1 at 250 ?mol·m-2·s-1. There was no difference in PEP activity at low light levels. The rubisco activity was lower at 1650 and 3000 ppm CO2. Increases in NAR correlate more closely to the PEP-Case than to Rubisco activity. Physiological significance of high activity of PEP-Case over rubisco will be discussed

  1. Other enrichment related contracts

    International Nuclear Information System (INIS)

    In addition to long-term enrichment contracts, DOE has other types of contracts: (1) short-term, fixed-commitment enrichment contract; (2) emergency sales agreement for enriched uranium; (3) feed material lease agreement; (4) enriched uranium storage agreement; and (5) feed material usage agreement

  2. Characterization of the denitrifying fraction of phosphate accumulating organisms in biological phosphate removal

    DEFF Research Database (Denmark)

    Meinhold, Jens; Filipe, Carlos D.M.

    1999-01-01

    Results of experimental investigations are presented that strongly support the hypothesis that PAO from activated sludge systems consist of two groups: a) denitrifying PAO (DNPAO) capable of using oxygen and nitrate and b) non-denitrifying PAO (non-DNPAO) only able to use oxygen. Batch experiments were performed in which activated sludge obtained from a pilot scale BIODENIPHO(TM) was submitted to a sequence of anaerobic/anoxic/aerobic, anaerobic/aerobic or anaerobic/anoxic conditions while monitoring the course of NOX-N, NH4-N, PO4-P, PHB and PHV. Several methods for the determination of the two fractions of PAO are performed and compared. This study extends on previously reported results (Kerrn-Jespersen and Henze, 1993) in that the pH was controlled to around pH 7 to assure that phosphate precipitation was minimal, and in the measurement of PHB and PHV. With regards to the latter, the paper also examines the influence of the size of the internal PHA pool on the anoxic phosphorus uptake rate. Simulations implementing existing models for the growth of non-DNPAO and DNPAO are used to confirm the experimental results and to gain a better understanding of some of the observations. (C) 1999 IAWQ Published by Elsevier Science Ltd. All rights reserved.

  3. Evaluation of the microbial diversity of denitrifying bacteria in batch reactor

    Scientific Electronic Library Online (English)

    S. I., Maintinguer; I. K., Sakamoto; M. A. T., Adorno; M. B. A., Varesche.

    2013-09-01

    Full Text Available Microbial communities in an industrial activated sludge plant may contribute to the denitrification process, but the information on the microorganisms present in denitrifying reactors is still scarce. Removal of inorganic nitrogen compounds can be accomplished by the addition of carbon sources to th [...] e biological process of denitrification. Ethanol is an economically viable alternative as a carbon source in tropical countries like Brazil, with large-scale production from sugarcane. This paper reports the successful aplication of activated sludge with nitrate and ethanol in a batch anaerobic reactor. The operation lasted 61.5 h with total consumption of nitrate in 42.5 h, nitrite generation (2.0 mg/L) and ethanol consumption (830.0 mg/L) in 23.5 h. Denitrifying cell counts by the most probable number at the start of the operation were lower than at the end, confirming the ability of the inoculum from activated sludge for the denitrification process. The samples from cell counts were identified as Acidovorax sp., Acinetobacter sp., Comamonas sp. and uncultured bacteria. Therefore, these species may be involved in nitrate reduction and ethanol consumption in the batch reactor.

  4. Identification of active denitrifiers in rice paddy soil by DNA- and RNA-based analyses.

    Science.gov (United States)

    Yoshida, Megumi; Ishii, Satoshi; Fujii, Daichi; Otsuka, Shigeto; Senoo, Keishi

    2012-01-01

    Denitrification occurs markedly in rice paddy fields; however, few microbes that are actively involved in denitrification in these environments have been identified. In this study, we used a laboratory soil microcosm system in which denitrification activity was enhanced. DNA and RNA were extracted from soil at six time points after enhancing denitrification activity, and quantitative PCR and clone library analyses were performed targeting the 16S rRNA gene and denitrification functional genes (nirS, nirK and nosZ) to clarify which microbes are actively involved in denitrification in rice paddy soil. Based on the quantitative PCR results, transcription levels of the functional genes agreed with the denitrification activity, although gene abundance did not change at the DNA level. Diverse denitrifiers were detected in clone library analysis, but comparative analysis suggested that only some of the putative denitrifiers, especially those belonging to the orders Neisseriales, Rhodocyclales and Burkholderiales, were actively involved in denitrification in rice paddy soil. PMID:22972387

  5. Molecular approaches to understand the regulation of N2O emission from denitrifying bacteria - model strains and soil communities (Invited)

    Science.gov (United States)

    Frostegard, A.; Bakken, L. R.

    2010-12-01

    Emissions of N2O from agricultural soils are largely caused by denitrifying bacteria. Field measurements of N2O fluxes show large variations and depend on several environmental factors, and possibly also on the composition of the denitrifying microbial community. The temporal and spatial variation of fluxes are not adequately captured by biogeochemical models, and few options for mitigations have been invented, which underscores the need to understand the mechanisms underlying the emissions of N2O. Analyses of denitrification genes and transcripts extracted from soils are important for describing the system, but may have limited value for prediction of N2O emissions. In contrast, phenotypic analyses are direct measures of the organisms’ responses to changing environmental conditions. Our approach is to combine phenotypic characterizations using high-resolution gas kinetics, with gene transcription analyses to study denitrification regulatory phenotypes (DRP) of bacterial strains or complex microbial communities. The rich data sets obtained provide a basis for refinement of biochemical and physiological research on this key process in the nitrogen cycle. The strength of this combined approach is illustrated by a series of experiments investigating effects of soil pH on denitrification. Soil pH emerges as a master variable determining the microbial community composition as well as its denitrification product ratio (N2O/N2), with higher ratio in acid than in alkaline soil. It is therefore likely that emissions of N2O from agro-ecosystems will increase in large parts of the world where soil pH is decreasing due to intensified management and increased use of chemical fertilizers. Considering its immense implications, surprisingly few attempts have been made to unravel the mechanisms involved in the pH-control of the product stoichiometry of denitrification. We investigated the kinetics of gas transformations (O2, NO, N2O and N2) and transcription of functional genes in intact soil samples from long-term liming experiments. Expression of nirS (encoding nitrite reductase) and nosZ (encoding N2OR) was generally lower at pH6 compared to pH8, but the nosZ/nirS transcript ratios were similar or even higher at pH6. These results were largely corroborated in refined experiments using extracted bacterial communities from the same soils, which allowed us to better control the pH levels experienced by the cells. The findings indicated that the higher N2O/N2 product ratios at pH6 were due to a post-transcriptional effect. Pure culture experiments using Paracoccus denitrificans demonstrated very low N2O/N2 ratios at pH7 while N2O reduction was severely inhibited by suboptimal pH, and that this inhibition occurred during protein synthesis/assembly rather than at the transcription level. The results are important for the understanding of main factors affecting N2O emissions from terrestrial ecosystems.

  6. Beyond Job Enrichment to Employment Enrichment

    Science.gov (United States)

    Werther, William B., Jr.

    1975-01-01

    Employment enrichment views the total work environment confronting employees as a system consisting of two overlapping areas: worker-job and worker-organization subsystems. Job enrichment has improved the worker-job subsystem. The focus of this article is on methods of improving the worker-organization relationship. (Author/JB)

  7. Genome Sequence of the Deep-Sea Denitrifier Pseudomonas sp. Strain MT-1, Isolated from the Mariana Trench.

    Science.gov (United States)

    Fujinami, Shun; Oikawa, Yuji; Araki, Takuma; Shinmura, Yui; Midorikawa, Ryota; Ishizaka, Hikari; Kato, Chiaki; Horikoshi, Koki; Ito, Masahiro; Tamegai, Hideyuki

    2014-01-01

    Pseudomonas sp. strain MT-1 was the first deep-sea denitrifier isolated and characterized from mud recovered from a depth of 11,000 m in the Mariana Trench. We report here the genome sequence of this bacterium, which contributes to our understanding of denitrification and bioenergetics in the deep sea. PMID:25523772

  8. Genome Sequence of the Deep-Sea Denitrifier Pseudomonas sp. Strain MT-1, Isolated from the Mariana Trench

    OpenAIRE

    Fujinami, Shun; Oikawa, Yuji; Araki, Takuma; Shinmura, Yui; Midorikawa, Ryota; Ishizaka, Hikari; Kato, Chiaki; Horikoshi, Koki; ITO, Masahiro; Tamegai, Hideyuki

    2014-01-01

    Pseudomonas sp. strain MT-1 was the first deep-sea denitrifier isolated and characterized from mud recovered from a depth of 11,000 m in the Mariana Trench. We report here the genome sequence of this bacterium, which contributes to our understanding of denitrification and bioenergetics in the deep sea.

  9. Diversity of nitrite reductase genes (nirS) in the denitrifying water column of the coastal Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Jayakumar, D.A.; Francis, C.A.; Naqvi, S.W.A.; Ward, B.B.

    and nitrate distribution in the Arabian Sea coastal denitrifying region are reported. Phylogenetic analysis grouped 132 nirS Arabian Sea sequences into 12 major clusters. Most of the nirS sequences from the coastal water column did not show a high level...

  10. Cultivation and irradiation of human fibroblasts in a medium enriched with platelet lysate for obtaining feeder layer in epidermal cell culture; Cultivo e irradiacao de fibroblastos humanos em meio enriquecido com lisado de plaquetas para obtencao de camada de sustentacao em culturas de celulas da epiderme

    Energy Technology Data Exchange (ETDEWEB)

    Yoshito, Daniele

    2011-07-01

    For over 30 years, the use of culture medium, enriched with bovine serum, and murines fibroblasts, with the rate of proliferation controlled by irradiation or by share anticarcinogenic drugs, has been playing successfully its role in assisting in the development of keratinocytes in culture, for clinical purposes. However, currently there is a growing concern about the possibility of transmitting prions and animals viruses to transplanted patients. Taking into account this concern, the present work aims to cultivate human fibroblasts in a medium enriched with human platelets lysate and determine the irradiation dose of these cells, for obtaining feeder layer in epidermal cell culture. For carrying out the proposed objective, platelets lysis has standardized, this lysate was used for human fibroblasts cultivation and the irradiation dose enough to inhibit its duplication was evaluated. Human keratinocytes were cultivated in these feeder layers, in culture medium enriched with the lysate. With these results we conclude that the 10% platelets lysate promoted a better adhesion and proliferation of human fibroblasts and in all dose levels tested (60 to 300 Gy), these had their mitotic activity inactivated by ionizing irradiation, being that the feeder layers obtained with doses from 70 to 150 Gy were those that provided the best development of keratinocytes in medium containing 2.5% of human platelet lysate. Therefore, it was possible to standardize both the cultivation of human fibroblasts as its inactivation for use as feeder layer in culture of keratinocytes, so as to eliminate xenobiotics components. (author)

  11. Nitrous oxide reductase genes (nosZ) of denitrifying populations in soil and the earthworm gut are phylogenetically similar

    DEFF Research Database (Denmark)

    Horn, Marcus A.; Drake, Harold L.; Schramm, Andreas

    2006-01-01

    Earthworms emit nitrous oxide (N2O) and dinitrogen (N2). It has been hypothesized that the in situ conditions of the earthworm gut activates ingested soil denitrifiers during gut passage and leads to these in vivo emissions (M. A. Horn, A. Schramm, and H. L. Drake, Appl. Environ. Microbiol. 69:1662-1669, 2003). This hypothesis implies that the denitrifiers in the earthworm gut are not endemic to the gut but rather are regular members of the soil denitrifier population. To test this hypothesis, t...

  12. Derived enriched uranium market

    International Nuclear Information System (INIS)

    The potential impact on the uranium market of highly enriched uranium from nuclear weapons dismantling in the Russian Federation and the USA is analyzed. Uranium supply, conversion, and enrichment factors are outlined for each country; inventories are also listed. The enrichment component and conversion components are expected to cause little disruption to uranium markets. The uranium component of Russian derived enriched uranium hexafluoride is unresolved; US legislation places constraints on its introduction into the US market

  13. Enrichment of recycled uranium

    International Nuclear Information System (INIS)

    The centrifuge enrichment process is well suited for the re-enrichment of uranium recovered during reprocessing. BNFL has participated fully with Urenco shareholders in studies which have enabled Urenco to offer commercial enrichment services on recycled uranium. The paper examines aspects of chemical and radiological purity of enrichment plant feed and product. Additionally the effects of programming the flow of reprocessed uranium throughout the fuel cycle are examined and the potential economic incentives quantified. (author)

  14. Denitrifying sulfide removal process on high-salinity wastewaters in the presence of Halomonas sp.

    Science.gov (United States)

    Liu, Chunshuang; Zhao, Dongfeng; Ma, Wenjuan; Guo, Yadong; Wang, Aijie; Wang, Qilin; Lee, Duu-Jong

    2016-02-01

    Biological conversion of sulfide, acetate, and nitrate to, respectively, elemental sulfur (S(0)), carbon dioxide, and nitrogen-containing gas (such as N2) at NaCl concentration of 35-70 g/L was achieved in an expanded granular sludge bed (EGSB) reactor. A C/N ratio of 1:1 was noted to achieve high sulfide removal and S(0) conversion rate at high salinity. The extracellular polymeric substance (EPS) quantities were increased with NaCl concentration, being 11.4-mg/g volatile-suspended solids at 70 mg/L NaCl. The denitrifying sulfide removal (DSR) consortium incorporated Thauera sp. and Halomonas sp. as the heterotrophs and Azoarcus sp. being the autotrophs at high salinity condition. Halomonas sp. correlates with the enhanced DSR performance at high salinity. PMID:26454867

  15. Continuous nitrous oxide abatement in a novel denitrifying off-gas bioscrubber.

    Science.gov (United States)

    Frutos, Osvaldo D; Arvelo, Ilan A; Pérez, Rebeca; Quijano, Guillermo; Muñoz, Raúl

    2015-04-01

    The potential of a bioscrubber composed of a packed bed absorption column coupled to a stirred tank denitrification bioreactor (STR) was assessed for 95 days for the continuous abatement of a diluted air emission of N2O at different liquid recycling velocities. N2O removal efficiencies of up to 40?±?1 % were achieved at the highest recirculation velocity (8 m h(-1)) at an empty bed residence time of 3 min using a synthetic air emission containing N2O at 104?±?12 ppmv. N2O was absorbed in the packed bed column and further reduced in the STR at efficiencies >80 % using methanol as electron donor. The long-term operation of the bioscrubber suggested that the specialized N2O degrading community established was not able to use N2O as nitrogen source. Additional nitrification assays showed that the activated sludge used as inoculum was not capable of aerobically oxidizing N2O to nitrate or nitrite, regardless of the inorganic carbon concentration tested. Denitrification assays confirmed the ability of non-acclimated activated sludge to readily denitrify N2O at a specific rate of 3.9 mg N2O g VSS h(-1) using methanol as electron donor. This study constitutes, to the best of our knowledge, the first systematic assessment of the continuous abatement of N2O in air emission. A characterization of the structure of the microbial population in the absorption column by DGGE-sequencing revealed a high microbial diversity and the presence of heterotrophic denitrifying methylotrophs. PMID:25547842

  16. [Denitrifying bacteria of constructed wetland system based on nitrous oxide reductase gene (nosZ)].

    Science.gov (United States)

    Wang, Xiao-Jun; Chen, Shao-Hua; Zhang, Zhao-Ji; Xiao, Jun-Chao

    2012-04-01

    A horizontal subsurface flow constructed wetland was used to treat micro-pollution surface water and its effluent flowed into a landscape river as the water supplement. The abundance of the nitrous oxide reductase gene nosZ and 16S rDNA was investigated for the rhizosphere soil of the constructed wetland and the sediment of the landscape river by quantitive PCR. The diversity and similarity of denitrifiers were studied by using PCR-DGGE technique targeting the functional gene nosZ. The quantitive PCR results showed that the copy number of 16S rDNA and nosZ gene of the rhizosphere soil of the constructed wetland and the sediment of the landscape river were 1.91E + 07, 1.26E + 06 and 2.68E + 07, 8.37E + 05 copies x ng(-1) (by DNA), and 1.45E + 11, 9.31E + 09 and 5.31E + 11, 1.45E + 10 copies x g(-1) (by dry soil), respectively. Generally, the total bacterial count and denitrifiers in the sediment of the landscape river was higher than that of the constructed wetland, but the relative abundance of nosZ of the latter (3.8% - 10.1%) was significantly higher than that of the former (1.7% - 4.1%). There was low similarity between the two niches in cluster analysis. The predominant species of rhizosphere soil were mainly contained Rhodobacearales, Rhizobiales and Burkholderiales, although the predominant species of sediment were uncultured bacteria. PMID:22720582

  17. Coexistence of nitrifying, anammox and denitrifying bacteria in a sequencing batch reactor.

    Science.gov (United States)

    Langone, Michela; Yan, Jia; Haaijer, Suzanne C M; Op den Camp, Huub J M; Jetten, Mike S M; Andreottola, Gianni

    2014-01-01

    Elevated nitrogen removal efficiencies from ammonium-rich wastewaters have been demonstrated by several applications, that combine nitritation and anammox processes. Denitrification will occur simultaneously when organic carbon is also present. In this study, the activity of aerobic ammonia oxidizing, anammox and denitrifying bacteria in a full scale sequencing batch reactor, treating digester supernatants, was studied by means of batch-assays. AOB and anammox activities were maximum at pH of 8.0 and 7.8-8.0, respectively. Short term effect of nitrite on anammox activity was studied, showing nitrite up to 42 mg/L did not result in inhibition. Both denitrification via nitrate and nitrite were measured. To reduce nitrite-oxidizing activity, high NH3-N (1.9-10 mg NH3-N/L) and low nitrite (3-8 mg TNN/L) are required conditions during the whole SBR cycle. Molecular analysis showed the nitritation-anammox sludge harbored a high microbial diversity, where each microorganism has a specific role. Using ammonia monooxygenase ?-subunit (amoA) gene as a marker, our analyses suggested different macro- and micro-environments in the reactor strongly affect the AOB community, allowing the development of different AOB species, such as N. europaea/eutropha and N. oligotropha groups, which improve the stability of nitritation process. A specific PCR primer set, used to target the 16S rRNA gene of anammox bacteria, confirmed the presence of the "Ca. Brocadia fulgida" type, able to grow in presence of organic matter and to tolerate high nitrite concentrations. The diversity of denitrifiers was assessed by using dissimilatory nitrite reductase (nirS) gene-based analyses, who showed denitifiers were related to different betaproteobacterial genera, such as Thauera, Pseudomonas, Dechloromonas and Aromatoleum, able to assist in forming microbial aggregates. Concerning possible secondary processes, no n-damo bacteria were found while NOB from the genus Nitrobacter was detected. PMID:24550899

  18. Coexistence of nitrifying, anammox and denitrifying bacteria in a sequencing batch reactor

    Directory of Open Access Journals (Sweden)

    MichelaLangone

    2014-02-01

    Full Text Available Elevated nitrogen removal efficiencies from ammonium-rich wastewaters have been demonstrated by several applications, that combine nitritation and anammox processes. Denitrification will occur simultaneously when organic carbon is also present. In this study, the activity of aerobic ammonia oxidizing, anammox and denitrifying bacteria in a full scale Sequencing Batch Reactor, treating digester supernatants, was studied by means of batch-assays. AOB and anammox activities were maximum at pH of 8.0 and 7.8-8.0, rispectively. Short term effect of nitrite on anammox activity was studied, showing nitrite up to 42 mg/L did not result in inhibition. Both denitrification via nitrate and nitrite were measured. To reduce nitrite-oxidizing activity, high of NH3 – N (1.9-10 mg N-NH3/L and low nitrite (3-8 mg TNN/L are required conditions during the whole SBR cycle.Molecular analysis showed the nitritation-anammox sludge harbored a high microbial diversity, where each microorganism has a specific role. Using ammonia monooxygenase ? –subunit (amoA gene as a marker, our analyses suggested different macro- and micro-environments in the reactor strongly affect the AOB community, allowing the development of different AOB species, such as N. europaea/eutropha and N. oligotropha groups, which improve the stability of nitritation process. A specific PCR primer set, used to target the 16S rRNA gene of anammox bacteria, confirmed the presence of the “Ca. Brocadia fulgida” type, able to grow in precence of organic matter and to tolerate high nitrite concentrations. The diversity of denitrifiers was assessed by using dissimilatory nitrite reductase (nirS gene-based analyses, who showed denitifiers were related to different betaproteobacterial genera, such as Thauera, Pseudomonas, Dechloromonas and Aromatoleum, able to assist in forming microbial aggregates. Concerning possible secondary processes, no n-damo bacteria were found while NOB from the genus of Nitrobacter was detected.

  19. Uranium Enrichment, an overview

    International Nuclear Information System (INIS)

    This general presentation on uranium enrichment will be followed by lectures on more specific topics including descriptions of enrichment processes and assessments of the prevailing commercial and industrial situations. I shall therefore avoid as much as possible duplications with these other lectures, and rather dwell on: some theoretical aspects of enrichment in general, underlying the differences between statistical and selective processes, a review and comparison between enrichment processes, remarks of general order regarding applications, the proliferation potential of enrichment. It is noteworthy that enrichment: may occur twice in the LWR fuel cycle: first by enriching natural uranium, second by reenriching uranium recovered from reprocessing, must meet LWR requirements, and in particular higher assays required by high burn up fuel elements, bears on the structure of the entire front part of the fuel cycle, namely in the conversion/reconversion steps only involving UF6 for the moment. (author). tabs., figs., 4 refs

  20. Enrichment of high ammonia tolerant methanogenic culture

    OpenAIRE

    Fotidis, Ioannis; Karakashev, Dimitar Borisov; Proietti, Nicolas; Angelidaki, Irini

    2012-01-01

    Ammonia is the major toxicant in full scale anaerobic digesters of animal wastes which are rich in proteins and/or urea, such as pig or poultry wastes. Ammonia inhibition decreases methane production rates, increases volatile fatty acids concentration and leads to economic losses for the biogas plants. The methods used today to counteract ammonia inhibition are slow and costexpensive. A new biological approach to avoid or counteract ammonia inhibition by using ammonia tolerant methanogens, co...

  1. The Role of plant type and salinity in the selection for the denitrifying community structure in the rhizosphere of wetland vegetation

    OpenAIRE

    Bañeras Vives, Lluís; Ruiz Rueda, Olaya; López i Flores, Rocío; Quintana Pou, Xavier; Hallin, Sara

    2012-01-01

    Coastal wetlands, as transient links from terrestrial to marine environments, are important for nitrogen removal by denitrification. Denitrification strongly depends on both the presence of emergent plants and the denitrifier communities selected by different plant species. In this study, the effects of vegetation and habitat heterogeneity on the community of denitrifying bacteria were investigated in nine coastal wetlands in two preserved areas of Spain. Sampling locations were selected to c...

  2. Advanced enrichment techniques

    International Nuclear Information System (INIS)

    BNFL is in a unique position in that it has commercial experience of diffusion enrichment, and of centrifuge enrichment through its associate company Urenco. In addition BNFL is developing laser enrichment techniques as part of a UK development programme in this area. The paper describes the development programme which led to the introduction of competitive centrifuge enrichment technology by Urenco and discusses the areas where improvements have and will continue to be made in the centrifuge process. It also describes the laser development programme currently being undertaken in the UK. The paper concludes by discussing the relative merits of the various methods of uranium enrichment, with particular reference to the enrichment market likely to obtain over the rest of the century. (author)

  3. [Effect of short-time drought process on denitrifying bacteria abundance and N2O emission in paddy soil].

    Science.gov (United States)

    Lu, Jing; Liu, Jin-Bo; Sheng, Rong; Liu, Yi; Chen, An-Lei; Wei, Wen-Xue

    2014-10-01

    In order to investigate the impact of drying process on greenhouse gas emissions and denitrifying microorganisms in paddy soil, wetting-drying process was simulated in laboratory conditions. N2O flux, redox potential (Eh) were monitored and narG- and nosZ-containing denitrifiers abundances were determined by real-time PCR. N2O emission was significantly increased only 4 h after drying process began, and it was more than 6 times of continuous flooding (CF) at 24 h. In addition, narG and nosZ gene abundances were increased rapidly with the drying process, and N2O emission flux was significantly correlated with narG gene abundance (P paddy soil. PMID:25796895

  4. The enrichment secondary market

    International Nuclear Information System (INIS)

    This paper will addresses two topics: the background to the present status of the enrichment secondary market and the future outlook of the secondary market in enrichment services, and the viability of the nuclear fuel brokerage industry. These two topics are inevitably connected, as most secondary market activity, not only in enrichment but also in natural uranium, has traditionally been conducted with the participation of brokers. Therefore, the author interrelates these topics

  5. Anaerobic Mineralization of Quaternary Carbon Atoms: Isolation of Denitrifying Bacteria on Pivalic Acid (2,2-Dimethylpropionic Acid)

    OpenAIRE

    Probian, Christina; Wülfing, Annika; Harder, Jens

    2003-01-01

    The degradability of pivalic acid was established by the isolation of several facultative denitrifying strains belonging to Zoogloea resiniphila, to Thauera and Herbaspirillum, and to Comamonadaceae, related to [Aquaspirillum] and Acidovorax, and of a nitrate-reducing bacterium affiliated with Moraxella osloensis. Pivalic acid was completely mineralized to carbon dioxide. The catabolic pathways may involve an oxidation to dimethylmalonate or a carbon skeleton rearrangement, a putative 2,2-dim...

  6. Pyruvic Oxime Nitrification and Copper and Nickel Resistance by a Cupriavidus pauculus, an Active Heterotrophic Nitrifier-Denitrifier

    OpenAIRE

    Miguel Ramirez; Jennifer Obrzydowski; Mary Ayers; Sonia Virparia; Meijing Wang; Kurtis Stefan; Richard Linchangco; Domenic Castignetti

    2014-01-01

    Heterotrophic nitrifiers synthesize nitrogenous gasses when nitrifying ammonium ion. A Cupriavidus pauculus, previously thought an Alcaligenes sp. and noted as an active heterotrophic nitrifier-denitrifier, was examined for its ability to produce nitrogen gas (N2) and nitrous oxide (N2O) while heterotrophically nitrifying the organic substrate pyruvic oxime [CH3–C(NOH)–COOH]. Neither N2 nor N2O were produced. Nucleotide and phylogenetic analyses indicated that the organism is a member of a ge...

  7. Structure and function of microbial communities in constructed wetlands - influence of environmental parameters and pesticides on denitrifying bacteria

    OpenAIRE

    Milenkovski, Susann

    2009-01-01

    This thesis addresses the interactions and relationships between natural aquatic bacterial communities, environmental parameters, anthropogenic chemicals and the denitrification pathway in the habitat of agricultural constructed wetlands. The main aim was to gain fundamental knowledge of the drivers behind the processes of the denitrification (i.e. nitrogen removal) in constructed wetlands, hence, the structure and function of the denitrifying bacterial community as efficient nitrogen removal...

  8. Aerobic and anoxic growth and nitrate removal capacity of a marine denitrifying bacterium isolated from a recirculation aquaculture system

    OpenAIRE

    Borges, Maria-Teresa; Sousa, André; de Marco, Paolo; De Matos, Ana,; Hönigova, Petra; Castro, Paula M. L

    2008-01-01

    Bacterial biofilters used in marine recirculation aquaculture systems need improvements to enhance nitrogen removal efficiency. Relatively little is known about biofilter autochthonous population structure and function. The present study was aimed at isolating and characterizing an Autochthonous denitrifying bacterium from a marine biofilter installed at a recirculation aquaculture system. Colonization of four different media in a marine fish farm was followed by isolation of various denit...

  9. Toxic effects exerted on methanogenic, nitrifying and denitrifying bacteria by chemicals used in a milk analysis laboratory

    OpenAIRE

    Lopez-Fiuza, J.; Buys, B.; Mosquera-Corral, A.; Omil, F.; Mendez, R.

    2002-01-01

    The toxic effects caused by the chemicals contained in wastewaters generated by laboratories involved in raw milk analyses were assessed using batch assays. These assays were carried out separately with methanogenic, ammonium-oxidizing, nitrite-oxidizing and denitrifying bacteria. Since sodium azide is one of the main components of the chemical mixture present in these streams, a set of assays was carried out with the whole chemical mixture, and another one was performed only with azide as th...

  10. Is soil fauna an important driver of key soil function ? the case of denitrifier communities in tropical soils

    OpenAIRE

    Brauman, Alain; Philippot, Laurent; Baudoin, Ezékiel; Djigal, Djibril; Gueye, M.; Rabary, B.; Assigbetse, K.; Lensi, R.; Villenave, Cécile; Blanchart, Eric

    2008-01-01

    According to recent estimations, soil animals represent as much as 23% of the total diversity of living organisms. If the importance of soil fauna on soil global microbial processes like mineralization is widely recognized, their impact on composition of soil microbial guilds, like denitrifiers, remains questionable. This study will resume several works undertaken on the influence of keystone tropical soil species (nematodes, termites, earthworms) on different parameters (activity- density an...

  11. Commercial developments in enrichment

    International Nuclear Information System (INIS)

    The significance of the dollars spent by government and industry so far on enrichment programs is enhanced by the number of engineering and component design and supply firms who have become involved in the public and private development and design projects. The knowhow gained from this experience provides the nucleus of the industrial manufacturing base for the unique enrichment technology necessary to build the future U.S. enrichment plants. The $1.5 billion CIP/CUP programs now under way and the $4.4 billion Portsmouth Add-On Plant are bringing the U.S. enrichment capacity to the capability to supply the contracted 323 GW of reactors, while conserving uranium by allowing operation at a lower, more nearly optimum tails assay. The government enrichment contract books have remained closed to new orders since July of 1975. Inevitably, new foreign enrichment projects are actively pursuing customers. Until the government or private U.S. enrichment ventures resume contracting activity, the foreign plants have no U.S. competition. The technology exists within ERDA and industry to maintain U.S. leadership in the world enrichment market if the institutional questions can be answered

  12. Uranium enrichment. Principles

    International Nuclear Information System (INIS)

    Uranium enrichment industry is a more than 60 years old history and has developed without practically no cost, efficiency or profit constraints. However, remarkable improvements have been accomplished since the Second World War and have led to the development of various competing processes which reflect the diversity of uranium compositions and of uranium needs. Content: 1 - general considerations: uranium isotopes, problem of uranium enrichment, first realizations (USA, Russia, Europe, Asia, other countries), present day situation, future needs and market evolution; 2 - principles of isotopic separation: processes classification (high or low enrichment), low elementary enrichment processes, equilibrium time, cascade star-up and monitoring, multi-isotopes case, uranium reprocessing; 3 - enrichment and proliferation. (J.S.)

  13. Biogeographical distribution of denitrifying anaerobic methane oxidizing bacteria in Chinese wetland ecosystems.

    Science.gov (United States)

    Zhu, Guibing; Zhou, Leiliu; Wang, Yu; Wang, Shanyun; Guo, Jianhua; Long, Xi-En; Sun, Xingbin; Jiang, Bo; Hou, Qiaoyun; Jetten, Mike S M; Yin, Chengqing

    2015-02-01

    The discovery of denitrifying anaerobic methane oxidation with nitrite as electron acceptor mediated by 'Candidatus?Methylomirabilis oxyfera' connected the biogeochemical carbon and nitrogen cycle in a new way. However, it is important to have a comprehensive understanding about the distribution of M.?oxyfera-like bacteria in the terrestrial realm, especially the wetland ecosystems that are known as the largest natural source of atmospheric methane. Here, our molecular evidence demonstrated that a wide geographical distribution of M.?oxyfera-like bacteria at oxic/anoxic interfaces of various wetlands (n?=?91) over the Chinese territory. Intriguingly, the M.?oxyfera-like bacteria were detected in some extreme environments, indicating that M.?oxyfera-like bacteria occupied a wide range of habitats. Quantitative polymerase chain reaction estimated that the abundance of M.?oxyfera-like bacteria ranged from 2.2?×?10(3) to 2.3?×?10(7) copies?g(-1) dry soil, and up to around 0.62% of the total number of bacteria. Moreover, the M.?oxyfera-like bacteria showed high biodiversity in wetland ecosystems based on the analysis of 462 pmoA and 287 16S rRNA gene sequences. The current study revealed the widespread distribution and biogeography of M.?oxyfera-like bacteria in the terrestrial system. PMID:25223900

  14. Quantity-activity relationship of denitrifying bacteria and environmental scaling in streams of a forested watershed

    Science.gov (United States)

    O'Connor, Ben L.; Hondzo, Miki; Dobraca, Dina; Lapara, Timothy M.; Finlay, Jacques C.; Brezonik, Patrick L.

    2006-12-01

    The spatial variability of subreach denitrification rates in streams was evaluated with respect to controlling environmental conditions, molecular examination of denitrifying bacteria, and dimensional analysis. Denitrification activities ranged from 0 and 800 ng-N gsed-1 d-1 with large variations observed within short distances (gene that encodes for nitrite reductase. Results showed a range of nirK quantities from 103 to 107 gene-copy-number gsed-1. A nonparametric statistical test showed no significant difference in nirK quantities among stream reaches, but revealed that samples with a high denitrification potential had significantly higher nirK quantities. Denitrification activity was positively correlated with nirK quantities with scatter in the data that can be attributed to varying environmental conditions along stream reaches. Dimensional analysis was used to evaluate denitrification activities according to environmental variables that describe fluid-flow properties, nitrate and organic material quantities, and dissolved oxygen flux. Buckingham's pi theorem was used to generate dimensionless groupings and field data were used to determine scaling parameters. The resulting expressions between dimensionless NO3- flux and dimensionless groupings of environmental variables showed consistent scaling, which indicates that the subreach variability in denitrification rates can be predicted by the controlling physical, chemical, and microbiological conditions.

  15. Evaluation of different culture media and enrichment in orange juice upon the growth of Alicyclobacillus spp. / Avaliação de diferentes meios de cultura e enriquecimento em suco de laranja sobre o crescimento de Alicyclobacillus spp.

    Scientific Electronic Library Online (English)

    Márcia Maria, Anjos; Suelen Pereira, Ruiz; Benício Alves, Abreu Filho.

    2014-04-01

    Full Text Available As bactérias do gênero Alicyiclobacillus spp. formam esporos e se desenvolvem em meios ácidos, podendo causar deterioração em sucos cítricos. O Brasil é o maior exportador de suco de laranja concentrado do mundo e, assim, este gênero vem sendo estudado por causar alterações de odor e sabor. Vários e [...] studos relatam diferentes meios de culturas empregados para a detecção e enumeração de Alicyclobacillus spp. Este estudo teve como objetivo avaliar a recuperação de esporos de Alicyclobacillus spp. nos meios ALI, BAT, K ágar e YSG, utilizando a metodologia indicada pela ABECitrus. Cinco inóculos diferentes foram utilizados, sendo dois de linhagens-referência e os outros três isolados de suco concentrado de laranja pasteurizado. Também foi verificada a recuperação das células após o enriquecimento em suco de laranja reconstituído. Foi inoculada uma população inicial de 6 log UFC/mL. Os meios ALI, BAT e YSG conseguiram recuperar esta população nos diferentes inóculos, não existindo diferenças significativas entre os resultados. Contudo, devido à facilidade do preparo, os meios ALI e YSG mostraram-se mais vantajosos quando comparados ao meio BAT. O meio K ágar apresentou recuperação inferior aos outros meios para todos os inóculos, porém, houve diferença significativa apenas para Alicyclobacillus acidocaldarius 0298 T (3,66 log UFC/mL) e Alicyclobacillus pomorum-like CBMAI 0278 (4,11 log UFC/mL). Abstract in english Bacteria of the genus Alicyiclobacillus spp. form spores and develop in acid media, leading to the spoilage of citrus juices. Brazil is the largest exporter of orange juice concentrate, and yet, it has been extensively studied due to changes in taste and smell. Several investigations have reported d [...] ifferent culture media used to detect and enumerate Alicyiclobacillus spp. The objective of the present study was to evaluate the recovery of Alicyiclobacillus spp. spores grown in ALI, BAT, K agar and YSG media using the methodology suggested by ABECitrus. Five inocula were used, two from reference strains and three from pasteurized concentrated orange juice. Cell recovery after the enrichment in reconstituted orange juice was also analyzed. An initial population of 6 log CFU/mL was inoculated. ALI, BAT and YSG media were able to recover the initial population of all different inocula, with no significant differences between the results. When compared to BAT, however, the preparation of ALI and YSG media was simpler and had more advantages. The recovery with K agar medium was lower than the other media for all the tested inocula, with significant differences found for Alicyclobacillus acidocaldarius 0298T (3.66 log CFU/mL) and Alicyclobacillus pomorum-like CBMAI 0278 (4.11 log CFU/mL).

  16. Developments in uranium enrichment

    International Nuclear Information System (INIS)

    The enrichment services market is still characterized by overcapacities. While consumption worldwide will rise by some 15% to 39,000 t SWU/a over the next ten years, capacities amount to nearly 50,000 t SWU/a. The price for enrichment services probably has reached its all time low. Prices below U.S. $ 100/kg SWU are not likely to cover costs even of the economically most advanced enrichment processes. Urenco has prepared for the difficult enrichment business in the years to come by streamlining and cost cutting measures. The company intends to hold and increase its share of more than 10% in the world market. The uranium enrichment plant of Gronau will be expanded further. Expansion beyond 1000 t is subject to another permit being granted under the Atomic Energy Act, an application for which was filed in December 1994. Centrifuge technology is the superior enrichment technology, i.e., there is still considerable potential for further development. Construction of enrichment plants employing the centrifuge technology in the United States and in France is being pursued in various phases, from feasibility studies to licensing procedures. Before these plants could be implemented, however, considerable problems of organization would have to be solved, and the market would have to change greatly, respectively. The laser process, at the present time, does not seem to be able to develop into a major industrial competitor. (orig.)

  17. TRIGA low enrichment fuel

    International Nuclear Information System (INIS)

    Sixty TRIGA reactors have been sold and the earliest of these are now passing twenty years of operation. All of these reactors use the uranium zirconium hydride fuel (UZrH) which provides certain unique advantages arising out of its large prompt negative temperature coefficient, very low fission product release, and high temperature capability. Eleven of these Sixty reactors are conversions from plate fuel to TRIGA fuel which were made as a result of these advantages. With only a few exceptions, TRIGA reactors have always used low-enriched uranium (LEU) fuel with an enrichment of 19.9%. The exceptions have either been converted from the standard low-enriched fuel to the 70% enriched FLIP fuel in order to achieve extended lifetime, or are higher powered reactors which were designed for long life using 93%-enriched uranium during the time when the use and export of highly enriched uranium (HEU) was not restricted. The advent of international policies focusing attention on nonproliferation and safeguards made the HEU fuels obsolete. General Atomic immediately undertook a development effort (nearly two years ago) in order to be in a position to comply with these policies for all future export sales and also to provide a low-enriched alternative to fully enriched plate-type fuels. This important work was subsequently partially supported by the U.S. Department of Energy. The laboratory and production tests have shown that higher uranium densities can be achieved to compensate for reducing the enrichment to 20%, and that the fuels maintain the characteristics of the very thoroughly proven standard TRIGA fuels. In May of 1978, General Atomic announced that these fuels were available for TRIGA reactors and for plate-type reactors with power levels up to 15 MW with General Atomic's standard commercial warranty

  18. TRIGA low enrichment fuel

    International Nuclear Information System (INIS)

    Sixty TRIGA reactors have been sold and the earliest of these are now passing twenty years of operation. All of these reactors use the uranium-zirconium hydride fuel (UZrH) which provides certain unique advantages arising out of its large prompt negative temperature coefficient, very low fission product release, and high temperature capability. Eleven of these Sixty reactors are conversions from plate fuel to TRIGA fuel which were made as a result of these advantages. With only a few exceptions, TRIGA reactors have always used low-enriched-uranium (LEU) fuel with an enrichment of 19.9%. The exceptions have either been converted from the standard low-enriched fuel to the 70% enriched FLIP fuel in order to achieve extended lifetime, or are higher powered reactors which were designed for long life using 93%-enriched uranium during the time when the use and export of highly enriched uranium (HEU) was not restricted. The advent of international policies focusing attention on nonproliferation and safeguards made the HEU fuels obsolete. General Atomic immediately undertook a development effort (nearly two years ago) in order to be in a position to comply with these policies for all future export sales and also to provide a low-enriched alternative to fully enriched plate-type fuels. This important work was subsequently partially supported by the U.S. Department of Energy. The laboratory and production tests have shown that higher uranium densities can be achieved to compensate for reducing the enrichment to 20%, and that the fuels maintain the characteristics of the very thoroughly proven standard TRIGA fuels. In May of 1978, General Atomic announced that these fuels were available for TRIGA reactors and for plate-type reactors with power levels up to 15 MW with GA's standard commercial warranty

  19. Metal enrichment processes

    CERN Document Server

    Schindler, S

    2008-01-01

    There are many processes that can transport gas from the galaxies to their environment and enrich the environment in this way with metals. These metal enrichment processes have a large influence on the evolution of both the galaxies and their environment. Various processes can contribute to the gas transfer: ram-pressure stripping, galactic winds, AGN outflows, galaxy-galaxy interactions and others. We review their observational evidence, corresponding simulations, their efficiencies, and their time scales as far as they are known to date. It seems that all processes can contribute to the enrichment. There is not a single process that always dominates the enrichment, because the efficiencies of the processes vary strongly with galaxy and environmental properties.

  20. Uranium conversion and enrichment

    International Nuclear Information System (INIS)

    A description is given of the Atomic Energy Corporation's uranium conversion and enrichment plants at Valinda ba, including a brief discussion of problems encountered and plans for future developments. (author)

  1. Enrich Project Final Report

    OpenAIRE

    Nixon, William

    2010-01-01

    The Enrich project was a 12 month JISC project funded as part of the Inf11 Programme (2009-11). It was conducted in partnership by the Library, Research and Enterprise and IT Services – with additional technical support from EPrints Services. This interdepartmental approach was critical to the success of the project and the repository’s long term sustainability as an institutional [not simply Library] service. At its heart, Enrich provided a clear focus for the integration and enhance...

  2. Uranium enrichment technology

    International Nuclear Information System (INIS)

    A comparison of different enrichment technologies and their economic aspects offers guiding information on criteria for selecting plants still to be erected. The diffusion, centrifuge, and separation nozzle methods are considered as well as the so-called South-African method and isotope separation by means of laser light. The existing enrichment plants, those under construction, and those being planned justify the assumption that there can be no real lack of separation capacity within the next ten years. (orig.)

  3. Denitrifying and diazotrophic community responses to artificial warming in permafrost and tallgrass prairie soils.

    Science.gov (United States)

    Penton, Christopher R; St Louis, Derek; Pham, Amanda; Cole, James R; Wu, Liyou; Luo, Yiqi; Schuur, E A G; Zhou, Jizhong; Tiedje, James M

    2015-01-01

    Increasing temperatures have been shown to impact soil biogeochemical processes, although the corresponding changes to the underlying microbial functional communities are not well understood. Alterations in the nitrogen (N) cycling functional component are particularly important as N availability can affect microbial decomposition rates of soil organic matter and influence plant productivity. To assess changes in the microbial component responsible for these changes, the composition of the N-fixing (nifH), and denitrifying (nirS, nirK, nosZ) soil microbial communities was assessed by targeted pyrosequencing of functional genes involved in N cycling in two major biomes where the experimental effect of climate warming is under investigation, a tallgrass prairie in Oklahoma (OK) and the active layer above permafrost in Alaska (AK). Raw reads were processed for quality, translated with frameshift correction, and a total of 313,842 amino acid sequences were clustered and linked to a nearest neighbor using reference datasets. The number of OTUs recovered ranged from 231 (NifH) to 862 (NirK). The N functional microbial communities of the prairie, which had experienced a decade of experimental warming were the most affected with changes in the richness and/or overall structure of NifH, NirS, NirK and NosZ. In contrast, the AK permafrost communities, which had experienced only 1 year of warming, showed decreased richness and a structural change only with the nirK-harboring bacterial community. A highly divergent nirK-harboring bacterial community was identified in the permafrost soils, suggesting much novelty, while other N functional communities exhibited similar relatedness to the reference databases, regardless of site. Prairie and permafrost soils also harbored highly divergent communities due mostly to differing major populations. PMID:26284038

  4. Nitrate reduction by denitrifying anaerobic methane oxidizing microorganisms can reach a practically useful rate.

    Science.gov (United States)

    Cai, Chen; Hu, Shihu; Guo, Jianhua; Shi, Ying; Xie, Guo-Jun; Yuan, Zhiguo

    2015-12-15

    Methane in biogas has been proposed to be an electron donor to facilitate complete nitrogen removal using denitrifying anaerobic methane oxidizing (DAMO) microorganisms in an anaerobic ammonium oxidation (anammox) reactor, by reducing the nitrate produced. However, the slow growth and the low activity of DAMO microorganisms cast a serious doubt about the practical usefulness of such a process. In this study, a previously established lab-scale membrane biofilm reactor (MBfR), with biofilms consisting of a coculture of DAMO and anammox microorganisms, was operated to answer if the DAMO reactor can achieve a nitrate reduction rate that can potentially be applied for wastewater treatment. Through progressively increasing nitrate and ammonium loading rates to the reactor, a nitrate removal rate of 684 ± 10 mg-N L(-1)d(-1) was achieved after 453 days of operation. This rate is, to our knowledge, by far the highest reported for DAMO reactors, and far exceeds what is predicted to be required for nitrate removal in a sidestream (5.6-135 mg-N L(-1)d(-1)) or mainstream anammox reactor (3.2-124 mg-N L(-1)d(-1)). Mass balance analysis showed that the nitrite produced by nitrate reduction was jointly reduced by anammox bacteria at a rate of 354 ± 3 mg-N L(-1)d(-1), accompanied by an ammonium removal rate of 268 ± 2 mg-N L(-1)d(-1), and DAMO bacteria at a rate of 330 ± 9 mg-N L(-1)d(-1). This study shows that the nitrate reduction rate achieved by the DAMO process can be high enough for removing nitrate produced by anammox process, which would enable complete nitrogen removal from wastewater. PMID:26414889

  5. Simultaneous electricity generation and pollutant removal in microbial fuel cell with denitrifying biocathode over nitrite

    International Nuclear Information System (INIS)

    Highlights: • An MFC was successfully started up using nitrite as cathodic electron acceptor. • The optimal HRT was deemed to be 8 h in this study. • The suitable temperature for power generation was found to be 20 °C. • The suitable temperature for pollutant removal was found to be 25 °C. • Free buffer led to 50% decrease of TN removal rate and power generation. - Abstract: The influences of hydraulic retention time, temperature and free buffer on the performance of short-cut denitrifying microbial fuel cell were investigated after it was successfully started up using nitrite as the cathodic electron acceptor. The results revealed that a power density of 8.3 ± 0.5 W m?3 NC was obtained after 15 days operation. The desirable hydraulic retention time was found in this study to be 8 h, with a COD removal rate of 2.117 ± 0.006 kg m?3 NC d?1 and a total nitrogen removal rate of 0.041 ± 0.002 kg m?3 NC d?1, respectively. It demonstrated that temperature had different effects on the electricity generation and pollutant removal performance of microbial fuel cell. The suitable temperature for power generation and pollutant removal was found to be 20 °C and 25 °C, respectively. Free buffer led to 50% decrease of both total nitrogen removal rate and power density of microbial fuel cell compared to that with phosphate buffer solution addition. The optimal total nitrogen removal rate obtained in the case with sodium azide addition (0.075 ± 0.008 kg m?3 NC d?1) increased by 50% as compared to that without sodium azide addition. It suggested that abolishing oxygen or inhibiting nitrite oxidizing bacteria would favor nitrogen removal

  6. Structure of a new azurin from the denitrifying bacterium Alcaligenes xylosoxidans at high resolution.

    Science.gov (United States)

    Dodd, F E; Hasnain, S S; Abraham, Z H; Eady, R R; Smith, B E

    1995-11-01

    It has been reported previously that Alcaligenes xylosoxidans (NC1MB 11015) grown under denitrifying conditions produces two azurins instead of the single previously identified azurin [Dodd, Hasnain, Hunter, Abraham, Debenham, Kanzler, Eldridge, Eady, Ambler & Smith (1995). Biochemistry. In the press]. The new azurin, called azurin II, has been crystallized as blue elongated rectangular prisms with the tetragonal space group P4(1)22 and unit-cell parameters a = b = 52.65, c = 100.63 A. X-ray crystallographic data extending to 1.9 A resolution were collected by the Weissenberg method using 200 x 400 mm image plates and synchrotron X-rays of wavelength 0.97 A. The three-dimensional structure of azurin II has been solved by the molecular-replacement method using the structure of azurin from Alcaligenes denitrificans NCTC 8582 with which this new azurin shows a close homology. The quality of the initial map was sufficient to predict a number of sequence differences. The model is currently refined to an R-factor of 18.8% with X-ray data between 8.5 and 1.9 A. The final model of 961 protein atoms, one Cu atom and 50 water molecules has r.m.s. deviations from ideality of 0.009 A for bond lengths and 1.7 degrees for bond angles. The overall structure is similar to that of the azurin from A. denitrificans NCTC 8582. It has a beta-barrel structure with the Cu atom located near the top end of the molecule. The Cu atom is coordinated to Ndelta of His46 and His117 at 2.02 A and to Sgamma of Cys112 at 2.12 A, while the carbonyl O atom of Gly45 and Sdelta atom of Met121 provide the additional interactions at 2.75 and 3.26 A, respectively. PMID:15299774

  7. Decaying cyanobacteria decrease N2O emissions related to diversity of intestinal denitrifiers of Chironomus plumosus

    Directory of Open Access Journals (Sweden)

    Xu Sun

    2014-10-01

    Full Text Available Nitrous oxide (N2O emission of fresh invertebrates has too long been neglected in eutrophic lakes, although the sediments these animals inhabit are presumably hot spots of N2O emission. Thus, the experiment in this research was designed to gain insight into the influence of cyanobacterial degradation on the N2O emission by fresh water invertebrates (Chironomus plumosus. The presence of decaying cyanobacteria in Lake Taihu decreased the N2O emission rate of Chironomus plumosus larvae from the larvae body by almost 400% for the larvae as a whole. The N2O emission rate decreased by 350% based on readings from studies of their gut, which was mostly due to stimulation of intestinal complete denitrification. The quantitative PCR results showed that intestinal gene abundance of nirK, nosZ (encoding the copper nitrite reductase and N2O reductase, respectively were significantly increased with the presence of decaying cyanobacteria. In contrast nirS (encoding the cytochrome cd1 heme nitrite reductase and the total bacteria decreased. In the gut of Chironomus plumosus, the diversity and richness of nosZ and nirK were lower with the cyanobacteria. Phylogenetic analysis of the intestinal function genes (nosZ and nirK showed that the nosZ- and nirK-type denitrifying bacterial sequences were related to different phylotypes. Hence, additional cyanobacteria increased the abundance, but decreased the richness and diversity of intestinal nitrate-reducing bacteria, probably by providing more carbon source in the gut. The data obtained in this study elucidates that the decaying cyanobacteria decreased the emissions of N2O by the aquatic invertebrates in freshwater sediment and could serve as a valuable resource for nitrogen removal affecting greenhouse gas emissions.

  8. Identification of the functional periplasmic nitrate reductase (nap) gene cluster from the deep-sea denitrifier Pseudomonas sp. strain MT-1.

    Science.gov (United States)

    Tamegai, Hideyuki; Ikeda, Eriko; Kato, Chiaki; Horikoshi, Koki

    2007-08-01

    The nap gene cluster encoding periplasmic nitrate reductase was identified from Pseudomonas sp. strain MT-1, a deep-sea denitrifier isolated from the Mariana Trench. The ORFs identified were highly homologous with those of Pseudomonas stutzeri, but the cluster included only four ORFs (napDABC), less than those in other organisms. For other bacteria, some additional small ORFs (such as napE, napF, napG, napH, and napK) are found in the nap gene cluster, although their physiological function is still unclear. The soluble fraction of MT-1 grown under denitrifying condition showed significant nitrate reductase activity. This observation suggests that the periplasmic nitrate reductase encoded by the gene cluster identified in this study is functional. The activity was highest when the organism was grown under denitrifying conditions, suggesting that the enzyme participates in dissimilatory nitrite reduction. PMID:17690469

  9. Denitrifiers in the surface zone are primarily responsible for the nitrous oxide emission of dairy manure compost

    International Nuclear Information System (INIS)

    Highlights: ? Nitrous oxide (N2O) productions of each compost zones were compared. ? The pile surface emitted significant fluxes of N2O. ? The isotopic signature of N2O from surface and NO2? amended core were different. ? The denitrifying gene abundance was significantly higher in pile surface than the pile core. -- Abstract: During the dairy manure composting process, significant nitrous oxide (N2O) emissions occur just after the pile turnings. To understand the characteristics of this N2O emission, samples were taken from the compost surface and core independently, and the N2O production was monitored in laboratory incubation experiments. Equal amounts of surface and core samples were mixed to simulate the turning, and the 15N isotope ratios within the molecules of produced N2O were analyzed by isotopomer analysis. The results showed that the surface samples emitted significant levels of N2O, and these emissions were correlated with NOx?-N accumulation. Moreover, the surface samples and surface-core mixed samples incubated at 30 °C produced N2O with a low site preference (SP) value (?0.9 to 7.0‰) that was close to bacteria denitrification (0‰), indicating that denitrifiers in the surface samples are responsible for this N2O production. On the other hand, N2O produced by NO2?-amended core samples and surface samples incubated at 60 °C showed unrecognized isotopic signatures (SP = 11.4–20.3‰). From these results, it was revealed that the N2O production occurring just after the turnings was mainly derived from bacterial denitrification (including nitrifier denitrification) of NOx?-N under mesophilic conditions, and surface denitrifying bacteria appeared to be the main contributor to this process

  10. Denitrifiers in the surface zone are primarily responsible for the nitrous oxide emission of dairy manure compost

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Koki, E-mail: k_maeda@affrc.go.jp [Dairy Research Division, National Agricultural Research Center for Hokkaido Region, National Agricultural and Food Research Organization, 1 Hitsujigaoka, Sapporo 062-8555 (Japan); Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan); Toyoda, Sakae [Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan); Hanajima, Dai [Dairy Research Division, National Agricultural Research Center for Hokkaido Region, National Agricultural and Food Research Organization, 1 Hitsujigaoka, Sapporo 062-8555 (Japan); Yoshida, Naohiro [Department of Environmental Chemistry and Engineering, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan)

    2013-03-15

    Highlights: ? Nitrous oxide (N{sub 2}O) productions of each compost zones were compared. ? The pile surface emitted significant fluxes of N{sub 2}O. ? The isotopic signature of N{sub 2}O from surface and NO{sub 2}{sup ?} amended core were different. ? The denitrifying gene abundance was significantly higher in pile surface than the pile core. -- Abstract: During the dairy manure composting process, significant nitrous oxide (N{sub 2}O) emissions occur just after the pile turnings. To understand the characteristics of this N{sub 2}O emission, samples were taken from the compost surface and core independently, and the N{sub 2}O production was monitored in laboratory incubation experiments. Equal amounts of surface and core samples were mixed to simulate the turning, and the {sup 15}N isotope ratios within the molecules of produced N{sub 2}O were analyzed by isotopomer analysis. The results showed that the surface samples emitted significant levels of N{sub 2}O, and these emissions were correlated with NO{sub x}{sup ?}-N accumulation. Moreover, the surface samples and surface-core mixed samples incubated at 30 °C produced N{sub 2}O with a low site preference (SP) value (?0.9 to 7.0‰) that was close to bacteria denitrification (0‰), indicating that denitrifiers in the surface samples are responsible for this N{sub 2}O production. On the other hand, N{sub 2}O produced by NO{sub 2}{sup ?}-amended core samples and surface samples incubated at 60 °C showed unrecognized isotopic signatures (SP = 11.4–20.3‰). From these results, it was revealed that the N{sub 2}O production occurring just after the turnings was mainly derived from bacterial denitrification (including nitrifier denitrification) of NO{sub x}{sup ?}-N under mesophilic conditions, and surface denitrifying bacteria appeared to be the main contributor to this process.

  11. Different response of nitrifiers and denitrifiers to re-wetting shape the NO release from soils in laboratory incubation experiments

    Science.gov (United States)

    Behrendt, Thomas; Wu, Dianming; Song, Guozheng; Pommerenke, Bianca; Braker, Gesche

    2014-05-01

    Laboratory incubation studies incubating soils at a wide range of soil moistures, soil temperatures and mixing ratios of NO in the headspace and inorganic nutrient contents (NH4+,NO3-, NO2-) showed that release rates of NO follow an exponential function with increasing soil temperature and an optimum function for soil moisture. This approach assumes that environmental factors play the dominant role in shaping an ecosystem and thereby microbial communities and control the NO release from soil. We determined the NO release rate for a dryland farming soil under flooding irrigation in Xinjiang, China, a mid-latitude agricultural soil (Mainz, Germany), and a rice paddy (Ambai, India) upon wetting and subsequent drying out of soils. Only the release rate for the mid-latitude agricultural soil followed an optimum function for soil moisture. Release rates for the dryland farming soil and rice paddy, however, followed a two maxima function with distinct maxima at higher and lower soil moisture. Acknowledgement of two distinct maxima is critical for more accurately assessing regional biogenic NO emissions of soils under field conditions. To analyse the response of nitrifiers and denitrifiers involved in NO turnover in more detail we linked molecular analysis of functional gene expression (nirK and nirS, bacterial and archaeal amoA) and microbial community composition to NO release rates. We could show that the maximal transcriptional activity of denitrifiers and ammonia oxidizers differs with soil moisture and that higher transcriptional activity of nirS-type denitrifiers at higher soil moisture and of archaeal ammonia oxidizers at lower soil moisture may explain the two maxima for NO release.

  12. Diversity of Nitrate-Reducing and Denitrifying Bacteria in a Marine Aquaculture Biofilter and their Response to Sulfide

    DEFF Research Database (Denmark)

    Krieger, Bärbel; Schwermer, Carsten U.; Rezakhani, Nastaran; Horn, Marcus A.; Gieseke, Armin; Cytryn, Eddie; Dror, Minz; van Rijn, Jaap; Drake, Harold L.; Schramm, Andreas

    2006-01-01

    DIVERSITY OF NITRATE-REDUCING AND DENITRIFYING BACTERIA IN A MARINE AQUACULTURE BIOFILTER AND THEIR RESPONSE TO SULFIDE B.U. Krieger 1,5, C. Schwermer 2, N. Rezakhani 5, M.A. Horn 1, A. Gieseke 2, E. Cytryn 3, D. Minz 3, J. van Rijn 4, H.L. Drake 1, A. Schramm 5 1 Dept. of Ecological Microbiology...... response to sulfide concentrations relevant for the system. Almost 500 nitrate-consuming isolates were screened by 16S rRNA gene-RFLP; for each RFLP pattern representatives were sequenced. In total, 40 different strains were identified, some of them novel species, mostly affiliating with...

  13. Functional diversity in the denitrifying biofilm of the methanol-fed marine denitrification system at the Montreal Biodome.

    Science.gov (United States)

    Auclair, Julie; Parent, Serge; Villemur, Richard

    2012-05-01

    Nitrate is a serious problem in closed-circuit public aquariums because its accumulation rapidly becomes toxic to many lifeforms. A moving bed biofilm denitrification reactor was installed at the Montreal Biodome to treat its 3,250-m(3) seawater system. Naturally occurring microorganisms from the seawater affluent colonized the reactor carriers to form a denitrifying biofilm. Here, we investigated the functional diversity of this biofilm by retrieving gene sequences related to narG, napA, nirK, nirS, cnorB, and nosZ. A total of 25 sequences related to these genes were retrieved from the biofilm. Among them, the corresponding napA1, nirK1, cnorB9, and nosZ3 sequences were identical to the corresponding genes found in Hyphomicrobium sp. NL23 while the narG1 and narG2 sequences were identical to the two corresponding narG genes found in Methylophaga sp. JAM1. These two bacterial strains were previously isolated from the denitrifying biofilm. To assess the abundance of denitrifiers and nitrate respirers in the biofilm, the gene copy number of all the narG, napA, nirS, and nirK sequences found in biofilm was determined by quantitative PCR. napA1, nirK1, narG1, and narG2, which were all associated with either Methylophaga sp. JAM1 or Hyphomicrobium sp. NL23, were the most abundant genes. The other genes were 10 to 10,000 times less abundant. nirK, cnorB, and nosZ but not napA transcripts from Hyphomicrobium sp. NL23 were detected in the biofilm, and only the narG1 transcripts from Methylophaga sp. JAM1 were detected in the biofilm. Among the 19 other genes, the transcripts of only two genes were detected in the biofilm. Our results show the predominance of Methylophaga sp. JAM1 and Hyphomicrobium sp. NL23 among the denitrifiers detected in the biofilm. The results suggest that Hyphomicrobium sp. NL23 could use the nitrite present in the biofilm generated by nitrate respirers such as Methylophaga sp. JAM1. PMID:22006549

  14. Uranium enrichment in Europe

    International Nuclear Information System (INIS)

    Until the mid 1970's, the USA had a monopoly of separation work. There is now sufficient capacity at the Eurodif and Urenco plants for fully servicing Europe, but the Americans still have a large proportion of the European market. In 1984/85, the international market was determined by a series of basic decisions by the American market leader, which in turn were determined by the world-wide marketing activities of the European concerns Eurodif and Urenco. The author deals with the present situation in the world market for separation work, the recent decisions by the US Department of Energy (DOE) in enrichment technology, the setting to work of the enrichment plant at Urenco Germany at Gronau, the successes of the Urenco centrifuge technique and the state of laser enrichment. (orig.)

  15. Centrifuge enrichment program

    International Nuclear Information System (INIS)

    Exxon Nuclear has been active in privately funded research and development of centrifuge enrichment technology since 1972. In October of 1975, Exxon Nuclear submitted a proposal to design, construct, and operate a 3000-MT SWU/yr centrifuge enrichment plant, under the provisions of the proposed Nuclear Fuel Assurance Act of 1975. The U.S. Energy Research and Development Administration (ERDA) accepted the proposal as a basis for negotiation. It was proposed to build a 1000-MT SWU/yr demonstration increment to be operational in 1982; and after successful operation for about one year, expand the facilities into a 3000-MT SWU/yr plant. As part of the overall centrifuge enrichment plant, a dedicated centrifuge manufacturing plant would be constructed; sized to support the full 3000-MT SWU/yr plant. The selection of the centrifuge process by Exxon Nuclear was based on an extremely thorough evaluation of current and projected enrichment technology; results show that the technology is mature and the process will be cost effective. The substantial savings in energy (about 93%) from utilization of the centrifuge option rather than gaseous diffusion is a compelling argument. As part of this program, Exxon Nuclear has a large hardware R and D program, plus a prototype centrifuge manufacturing capability in Malta, New York. To provide a full-scale machine and limited cascade test capability, Exxon Nuclear is constructing a $4,000,000 Centrifuge Test Facility in Richland, Washington. This facility was to initiate operations in the Fall of 1976. Exxon Nuclear is convinced that the centrifuge enrichment process is the rational selection for emergence of a commercial enrichment industry

  16. Advanced uranium enrichment processes

    International Nuclear Information System (INIS)

    Three advanced Uranium enrichment processes are dealt with in the report: AVLIS (Atomic Vapour LASER Isotope Separation), MLIS (Molecular LASER Isotope Separation) and PSP (Plasma Separation Process). The description of the physical and technical features of the processes constitutes a major part of the report. If further presents comparisons with existing industrially used enrichment technologies, gives information on actual development programmes and budgets and ends with a chapter on perspectives and conclusions. An extensive bibliography of the relevant open literature is added to the different subjects discussed. The report was drawn up by the nuclear research Centre (CEA) Saclay on behalf of the Commission of the European Communities

  17. Isolation of the {epsilon}-caprolactam denitrifying bacteria from a wastewater treatment system manufactured with acrylonitrile-butadiene-styrene resin

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C.-C. [Department of Environmental Engineering, Hungkuang University, Shalu, Taichung 433, Taiwan (China)]. E-mail: chunchin@sunrise.hk.edu.tw; Lee, C.-M. [Department of Environmental Engineering, National Chung Hsing University, Taichung 402, Taiwan (China)

    2007-06-25

    {epsilon}-Caprolactam has high COD and toxicity, so its discharge to natural water and soil systems may lead to an adverse environmental effect on water quality, endangering public health and welfare. This investigation attempts to isolate {epsilon}-caprolactam denitrifying bacteria from a wastewater treatment system manufactured with acrylonitrile-butadiene-styrene (ABS) resin. The goal is to elucidate the effectiveness of isolated pure strain and ABS mixed strains in treating {epsilon}-caprolactam from synthetic wastewater. The results reveal that Paracoccus versutus MDC-3 was isolated from the wastewater treatment system manufactured with ABS resin. The ABS mixed strains and P. versutus MDC-3 can consume up to 1539 mg/l {epsilon}-caprolactam to denitrify from synthetic wastewater. Complete {epsilon}-caprolactam removal depended on the supply of sufficient electron acceptors (nitrate). Strain P. versutus MDC-3, Hyphomicrobium sp. HM, Methylosinus pucelana and Magnetospirillum sp. CC-26 are related closely, according to the phylogenetic analyses of 16S rDNA sequences.

  18. Effect of carbon dioxide and bicarbonate as inorganic carbon sources on growth and adaptation of autohydrogenotrophic denitrifying bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Ghafari, Shahin; Hasan, Masitah [Department of Chemical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia); Aroua, Mohamed Kheireddine [Department of Chemical Engineering, Faculty of Engineering, University of Malaya, 50603 Kuala Lumpur (Malaysia)], E-mail: mk_aroua@um.edu.my

    2009-03-15

    Acclimation of autohydrogenotrophic denitrifying bacteria using inorganic carbon source (CO{sub 2} and bicarbonate) and hydrogen gas as electron donor was performed in this study. In this regard, activated sludge was used as the seed source and sequencing batch reactor (SBR) technique was applied for accomplishing the acclimatization. Three distinct strategies in feeding of carbon sources were applied: (I) continuous sparging of CO{sub 2}, (II) bicarbonate plus continuous sparging of CO{sub 2}, and (III) only bicarbonate. The pH-reducing nature of CO{sub 2} showed an unfavorable impact on denitrification rate; however bicarbonate resulted in a buffered environment in the mixed liquor and provided a suitable mean to maintain the pH in the desirable range of 7-8.2. As a result, bicarbonate as the only carbon source showed a faster adaptation, while carbon dioxide as the only carbon source as well as a complementary carbon source added to bicarbonate resulted in longer acclimation period. Adapted hydrogenotrophic denitrifying bacteria, using bicarbonate and hydrogen gas in the aforementioned pH range, caused denitrification at a rate of 13.33 mg NO{sub 3}{sup -}-N/g MLVSS/h for degrading 20 and 30 mg NO{sub 3}{sup -}-N/L and 9.09 mg NO{sub 3}{sup -}-N/g MLVSS/h for degrading 50 mg NO{sub 3}{sup -}-N/L.

  19. Denitrifying bacteria from the genus Rhodanobacter dominate bacterial communities in the highly contaminated subsurface of a nuclear legacy waste site

    Energy Technology Data Exchange (ETDEWEB)

    Green, Stefan [Florida State University; Prakash, Om [Florida State University; Jasrotia, Puja [Florida State University; Overholt, Will [Florida State University; Cardenas, Erick [Michigan State University, East Lansing; Hubbard, Daniela [Florida State University; Tiedje, James M. [Michigan State University, East Lansing; Watson, David B [ORNL; Schadt, Christopher Warren [ORNL; Brooks, Scott C [ORNL; Kostka, Joel [Florida State University

    2011-01-01

    The effect of long-term mixed-waste contamination, particularly uranium and nitrate, on the microbial community in the terrestrial subsurface was investigated at the field scale at the Oak Ridge Integrated Field Research Challenge (ORIFRC) site in Oak Ridge, TN. The abundance, community composition, and distribution of groundwater microorganisms were examined across the site during two seasonal sampling events. At representative locations, subsurface sediment was also examined from two boreholes, one sampled from the most heavily contaminated area of the site and another from an area with low contamination. A suite of DNA- and RNA-based molecular tools were employed for community characterization, including quantitative PCR of ribosomal RNA and nitrite reductase genes, community composition fingerprinting analysis, and high-throughput pyrotag sequencing of rRNA genes. The results demonstrate that pH is a major driver of the subsurface microbial community structure, and denitrifying bacteria from the genus Rhodanobacter (class Gammaproteobacteria) dominate at low pH. The relative abundance of bacteria from this genus was positively correlated with lower pH conditions, and these bacteria were abundant and active in the most highly contaminated areas. Other factors, such as concentration of nitrogen species, oxygen and sampling season did not appear to strongly influence the distribution of Rhodanobacter. Results indicate that these organisms are acid-tolerant denitrifiers, well suited to the acidic, nitrate-rich subsurface conditions, and pH is confirmed as a dominant driver of bacterial community structure in this contaminated subsurface environment.

  20. Estimate of denitrifying microbiota in tertiary sewage treatment and kinetics of the denitrification process using different sources of carbon

    Directory of Open Access Journals (Sweden)

    Marchetto Margarida

    2003-01-01

    Full Text Available A study of the kinetics of denitrification was carried out in the laboratory based on the quantification of N2O, the final product of the activity of denitrifying microorganisms, when the enzymatic reduction of N2O to N2 was blocked by acetylene. Concentrated mixed liquor (sludge from a reactor with intermittent aeration used for sewage treatment was used as the inoculum, while methanol, acetic acid, glucose, effluent sewage from an anaerobic fluidized bed reactor and synthetic substrate simulating domestic sewage were used as carbon sources. The mean concentration of nitrate was 20 mg/L. Maxima of N2O production and NO3- consumption occurred between 0.5h and 2.0h of incubation using all the carbon sources, which characterized the denitrification process. Acetic acid and methanol were responsible for the highest rates of N2O production. The estimated number of denitrifying microorganisms in the reactor with intermittent aeration, using the MPN technique, varied from 10(9 to 10(10 MPN/g VSS, indicating a high potential for the occurrence of denitrification.

  1. Effect of carbon dioxide and bicarbonate as inorganic carbon sources on growth and adaptation of autohydrogenotrophic denitrifying bacteria

    International Nuclear Information System (INIS)

    Acclimation of autohydrogenotrophic denitrifying bacteria using inorganic carbon source (CO2 and bicarbonate) and hydrogen gas as electron donor was performed in this study. In this regard, activated sludge was used as the seed source and sequencing batch reactor (SBR) technique was applied for accomplishing the acclimatization. Three distinct strategies in feeding of carbon sources were applied: (I) continuous sparging of CO2, (II) bicarbonate plus continuous sparging of CO2, and (III) only bicarbonate. The pH-reducing nature of CO2 showed an unfavorable impact on denitrification rate; however bicarbonate resulted in a buffered environment in the mixed liquor and provided a suitable mean to maintain the pH in the desirable range of 7-8.2. As a result, bicarbonate as the only carbon source showed a faster adaptation, while carbon dioxide as the only carbon source as well as a complementary carbon source added to bicarbonate resulted in longer acclimation period. Adapted hydrogenotrophic denitrifying bacteria, using bicarbonate and hydrogen gas in the aforementioned pH range, caused denitrification at a rate of 13.33 mg NO3--N/g MLVSS/h for degrading 20 and 30 mg NO3--N/L and 9.09 mg NO3--N/g MLVSS/h for degrading 50 mg NO3--N/L

  2. Preliminary insights into ?15N and ?18O of nitrate in natural mosses: A new application of the denitrifier method

    International Nuclear Information System (INIS)

    Natural mosses have been employed as reactive and accumulative indicators of atmospheric pollutants. Using the denitrifier method, the concentration, ?15N and ?18O of moss nitrate (NO3?) were measured to elucidate the sources of NO3? trapped in natural mosses. Oven drying at 55–70 °C, not lyophilization, was recommended to dry mosses for NO3? analyses. An investigation from urban to mountain sites in western Tokyo suggested that moss [NO3?] can respond to NO3? availability in different habitats. NO3? in terricolous mosses showed isotopic ratios as close to those of soil NO3?, reflecting the utilization of soil NO3?. Isotopic signatures of NO3? in corticolous and epilithic mosses elucidated atmospheric NO3? sources and strength from the urban (vehicle NOx emission) to mountain area (wet-deposition NO3?). However, mechanisms and isotopic effects of moss NO3? utilization must be further verified to enable the application of moss NO3? isotopes for source identification. - Highlights: ? Plant [NO3?] has been used to get insights into forest N saturation. ? However, detailed protocols were not established for plant [NO3?] analysis. ? Moreover, nitrogen/oxygen isotopic ratios of plant NO3? cannot be measured. ? We developed a new protocol for concentration and isotopic measurement of plant NO3?. ? The new method can open a new window to use these parameters for NO3? physiology. - Plant nitrate isotopes can be measured using the denitrifier method and nitrate isotopes of mosses are useful to differentiate atmospheric nitrate sources.

  3. Effects of elevated CO2 concentrations on denitrifying and nitrifying popualtions at terrestrial CO2 leakeage analogous sites

    Science.gov (United States)

    Christine, Dictor Marie; Catherine, Joulian; Valerie, Laperche; Stephanie, Coulon; Dominique, Breeze

    2010-05-01

    CO2 capture and geological storage (CCS) is recognized to be an important option for carbon abatement in Europe. One of the risks of CCS is the leakage from storage site. A laboratory was conducted on soil samples sampled near-surface from a CO2 leakage analogous site (Latera, Italy) in order to evaluate the impact of an elevated soil CO2 concentration on terrestrial bacterial ecosystems form near surface terrestrial environments and to determine a potential bacterial indicator of CO2 leakage from storage site. Surveys were conducted along a 50m long transect across the vent centre, providing a spectrum of CO2 flux rates, soil gas concentrations and compositions (Beaubien et al., 2007). A bacterial diversity studies, performed by CE-SSCP technique, on a soil profile with increasing CO2 soil concentrations (from 0.3% to 100%) showed that a change on bacterial diversity was noted when CO2 concentration was above 50 % of CO2. From this result, 3 soil samples were taken at 70 cm depth in 3 distinct zones (background soil CO2 content, soil CO2 content of 20% and soil CO2 content of 50%). Then theses soil samples were incubated under closed jars flushed with different air atmospheres (20, 50 and 90 % of CO2) during 18 months. At initial, 3, 6, 12 and 18 months, some soil samples were collected in order to estimate the denitrifying, nitrifying activities as a function of CO2 concentration content and times. Theses enzymatic activities were chosen because one occurs under anaerobic conditions (denitrification) and the other occurs under aerobic conditions (nitrification). Both of them were involved in the nitrogen cycle and are major actors of soil function and groundwater quality preservation. Metabolic diversity using BIOLOG Ecoplates was determined on every soil samples. Physico-chemical parameters (e.g. pH, bulk chemistry, mineralogy) were analyzed to have some information about the evolution of the soil during the incubation with increasing soil CO2 concentrations. Statistical analyses were performed to correlate microbiological measures and physico-chemical parameters. For the soil sampled in a zone with background CO2 content, incubation under an atmosphere with 20% of CO2, induce a sharp decrease of denitrifying activity after 6 months of incubation and only after 3 months with an atmosphere of 50% of CO2. On the contrary, concerning the soil sampled in a zone with 25.5% of CO2, incubation with an atmosphere of 50% has no effect on denitrifying activity and moreover this activity was stimulated with an atmosphere of 90% of CO2.Last, with the soil sampled in an area with 65.8% of CO2, denitrifying activity was negatively impacted from the 3th month of incubation with 90% CO2.and the activity was 2 fold lower after 12th of incubation. Concerning the nitrifying activity, soil sampled in an area with background CO2 content, this one remains little affected by increasing CO2 incubation. At initial times, soil sampled in the areas with 25.5 and 65.8 % of CO2 showed low level of nitrifying activities and further CO2 incubations have no effect on these activities. At the end, denitrifying activities seems to be more sensitive to CO2 concentrations evolution in the soil. More studies need to be done as incubation with lower CO2 content (affect the near-surface bacterial activities and identify a possible candidate of CO2 leakage from deep reservoirs.

  4. An enriching industrial project

    International Nuclear Information System (INIS)

    The TRICASTIN industrial gas-diffusion uranium enrichment plant which supplies fuel to nuclear power stations is discussed. A concise history of the plant is given and this is followed by a discussion on what has been learnt during the development. Financial, commercial, constructional, and multinational aspects are pinpointed. (L.F.)

  5. Enriching the Catalog

    Science.gov (United States)

    Tennant, Roy

    2004-01-01

    After decades of costly and time-consuming effort, nearly all libraries have completed the retrospective conversion of their card catalogs to electronic form. However, bibliographic systems still are really not much more than card catalogs on wheels. Enriched content that Amazon.com takes for granted--such as digitized tables of contents, cover…

  6. Prospects for uranium enrichment

    International Nuclear Information System (INIS)

    The biggest technological barrier to practical laser enrichment of U isotopes is the lack of suitable lasers. The major motivation behind studies of laser-induced photochemical enrichment of uranium is the potential efficiency of the technique. A gaseous-diffusion plant requires ten million times more energy to separate fissionable uranium-235 from the more-common uranium-238 than the theoretical minimum of 60 joules per gram calculated from the entropy of mixing one gram of 235U with 140 g of 238U. The centrifuge process requires only one-tenth the energy needed for gaseous diffusion, but laser techniques promise to be 100 times more efficient than the centrifuge. The laser approach also can provide higher enrichment factors per stage, thereby reducing energy requirements and size of a uranium-enrichment plant. It is noted that laser-induced isotope separation has been shown to be feasible with a variety of conceptually different approaches. The major challenge now is to build lasers with reliability and efficiency adequate to move the emphasis to economic feasibility

  7. Everyone Vegetarian, World Enriching

    OpenAIRE

    John Y. Wu

    2014-01-01

    This essay advocates global vegetarian diet. Firstly, seven personal health benefits and four global benefits of vegetarian dinners are specified to enrich the entire globe, and then, secondly, I explore concretely how to overcome internal hurdle and external hurdle, so as to effectively propagate vegetarian dinners throughout the world. Everyone wins, including animals!

  8. Designing job enrichment projects.

    Science.gov (United States)

    Clakeley, G L

    1988-01-01

    This paper describes a management strategy for a job satisfaction program utilized in a large occupational therapy department. The goal of the program is to retain satisfied, productive employees and reduce attrition of therapists and assistants. The use of job enrichment projects for occupational therapy assistants will be presented with brief descriptions of two projects. PMID:23944880

  9. Job Enrichment in Extension.

    Science.gov (United States)

    Fourman, Louis S.; Jones, Jo

    1997-01-01

    Interviews with 10 participants in Ohio State University's job enrichment program for midcareer extension agents found that 5 returned to their same jobs after the experience but only 2 felt challenged/renewed. Part-time participation while working made it difficult to balance responsibilities. More information and a structured orientation were…

  10. INFLUENCE OF ALTERNATIVE ELECTRON ACCEPTORS ON THE ANAEROBIC BIODEGRADABILITY OF CHLORINATED PHENOLS AND BENZOIC ACIDS

    Science.gov (United States)

    Nitrate, sulfate, and carbonate were used as electron acceptors to examine the anaerobic biodegradability of chlorinated aromatic compounds in estuarine and freshwater sediments. he respective denitrifying, sulfidogenic, and methanogenic enrichment cultures were established on ea...

  11. Availability of enrichment services

    International Nuclear Information System (INIS)

    The report summarizes major uncertainties which are likely to influence future demands for uranium isotopic enrichment. Since for the next decade the development of nuclear power will be largely concerned with the increment in demand the timely need for enrichment capacity will be particularly sensitive to assumptions about growth rates. Existing worldwide capacity together with capacities under construction will be sufficient well into the 1980's. However, long decision and construction leadtime, uncertainty as to future demand as well as other factors, specifically high capital need, all of which entail financial risks, create hindrances to a timely development of increment. The adequacy of current technology is well demonstrated in plant operation and new technology is under way. Technology is, however, not freely available on a purely commercial basis. Commercial willingness, which anticipates a limited degree of financial risk, is requesting both long term back-up from the utilities that would parallel their firm decisions on the acquisition of nuclear power units, and a protective government umbrella. This situation depends on the symbiotic relationship that exists between the nuclear power generating organizations, the enrichment undertakings and the governments involved. The report accordingly stresses the need for a more cooperative approach and this, moreover, at the multinational level. There is otherwise a risk that proper resources and financing means will not be allocated to the enrichment sector. Export limitations that request the highest degree of industrial processing of nuclear fuel, i.e. the compulsory enrichment of natural uranium, do not serve the interests of overall industrial efficiency

  12. Availability of enrichment services

    International Nuclear Information System (INIS)

    The report summarizes major uncertainties which are likely to influence future demands for uranium isotopic enrichment. Since for the next decade the development of nuclear power will be largely concerned with the increase in demand the need for enrichment capacity will then be particularly sensitive to assumptions about growth-rates. Existing world-wide capacity, together with capacities under construction, will be sufficient well into the 1980s. However, long decision and construction lead-time, uncertainty regarding future demand as well as other factors, specifically high capital need, all of which entail financial risks, create hindrances to a timely development of incremental capacity. The adequacy of current technology is well demonstrated in plant operation and new technology is under way. Technology is, however, not freely available on a purely commercial basis. Commercial willingness, which anticipates a limited degree of financial risk, requests both long-term back-up from the utilities that would parallel their firm decisions on the acquisition of nuclear power units, and a protective government umbrella. This situation depends on the symbiotic relationship that exists between the nuclear power generating organizations, the enrichment undertakings and the governments involved. The report accordingly stresses the need for a more co-operative approach and this, moreover, at the multinational level. There is otherwise a risk that proper resources and financing means will not be allocated to the enrichment sector. Export limitations that lead to a high degree of industrial processing of nuclear fuel, i.e. the obligatory enrichment of natural uranium, do not serve the interests of overall industrial efficiency. (author)

  13. Promotion of uranium enrichment business

    International Nuclear Information System (INIS)

    The Committee on Nuclear Power has studied on the basic nuclear power policy, establishing its five subcommittees, entrusted by the Ministry of Nternational Trade and Industry. The results of examination by the subcommittee on uranium enrichment business are given along with a report in this connection by the Committee. In order to establish the nuclear fuel cycle, the aspect of uranium enrichment is essential. The uranium enrichment by centrifugal process has proceeded steadily in Power Reactor and Nuclear Fuel Development Corporation. The following matters are described: the need for domestic uranium enrichment, the outlook for overseas enrichment services and the schedule for establishing domestic enrichment business, the current state of technology development, the position of the prototype enrichment plant, the course to be taken to establish enrichment business the main organization operating the prototype and commercial plants, the system of supplying centrifuges, the domestic conversion of natural uranium the subsidies for uranium enrichment business. (J.P.N.)

  14. The Enriched Xenon Observatory

    International Nuclear Information System (INIS)

    The Enriched Xenon Observatory (EXO) experiment will search for neutrinoless double beta decay of 136Xe. The EXO Collaboration is actively pursuing both liquid-phase and gas-phase Xe detector technologies with scalability to the ton-scale. The search for neutrinoless double beta decay of 136Xe is especially attractive because of the possibility of tagging the resulting Ba daughter ion, eliminating all sources of background other than the two neutrino decay mode. EXO-200, the first phase of the project, is a liquid Xe time projection chamber with 200 kg of Xe enriched to 80% in 136Xe. EXO-200, which does not include Ba-tagging, will begin taking data in 2009, with two-year sensitivity to the half-life for neutrinoless double beta decay of 6.4x1025 years. This corresponds to an effective Majorana neutrino mass of 0.13 to 0.19 eV.

  15. South Australia, uranium enrichment

    International Nuclear Information System (INIS)

    The Report sets out the salient data relating to the establishment of a uranium processing centre at Redcliff in South Australia. It is conceived as a major development project for the Commonwealth, the South Australian Government and Australian Industry comprising the refining and enrichment of uranium produced from Australian mines. Using the data currently available in respect of markets, demand, technology and possible financial return from overseas sales, the project could be initiated immediately with hexafluoride production, followed rapidly in stages by enrichment production using the centrifuge process. A conceptual development plan is presented, involving a growth pattern that would be closely synchronised with the mining and production of yellowcake. The proposed development is presented in the form of an eight-and-half-year programme. Costs in this Report are based on 1975 values, unless otherwise stated. (Author)

  16. Microbial Enrichment of Vermicompost

    OpenAIRE

    Kuppuraj Rajasekar; Thilagavathy Daniel; Natchimuthu Karmegam

    2012-01-01

    The present study has been conducted to explore the possibility of enrichment of vermicompost with microbial inoculants (i.e., biofertilizer organisms), Azospirillum brasilense and Rhizobium leguminosarum, optimization of inoculum level, and time of inoculation during vermicomposting. The survival rate of each microbial inoculant, total microbial population in vermicompost, and their correlation with the microbial inoculants during the storage period (180 days) were assessed. The change in po...

  17. Diversity of Nitrate-Reducing and Denitrifying Bacteria in a Marine Aquaculture Biofilter and their Response to Sulfide

    DEFF Research Database (Denmark)

    Krieger, Bärbel; Schwermer, Carsten U.

    2006-01-01

    DIVERSITY OF NITRATE-REDUCING AND DENITRIFYING BACTERIA IN A MARINE AQUACULTURE BIOFILTER AND THEIR RESPONSE TO SULFIDE B.U. Krieger 1,5, C. Schwermer 2, N. Rezakhani 5, M.A. Horn 1, A. Gieseke 2, E. Cytryn 3, D. Minz 3, J. van Rijn 4, H.L. Drake 1, A. Schramm 5 1 Dept. of Ecological Microbiology, University of Bayreuth, Bayreuth, Germany; 2 Max Planck Institute for Marine Microbiology, Bremen, Germany; 3 Institute for Soil, Water and Environmental Sciences, ARO, The Volcani Center, Bet Dagan, Israel; 4 Faculty of Agricultural, Food And Environmental Quality Sciences, The Hebrew University of Jerusalem, Rehovot, Israel; 5 Dept of Biological Sciences, Microbiology, University of Aarhus, Denmark Conventional aquaculture systems release nitrogen compounds and organic matter into marine environments. As an environmentally-friendly alternative, a zero-discharge mariculture system recently was developed containing a 3-stage biofilter for nitrification, denitrification/anaerobic sludge digestion, and sulfide oxidation. Sulfate reduction in the anaerobic part of the system leads to sulfide concentrations exceeding 5 mM, which may affect nitrate reduction and denitrification. Sulfide can inhibit nitrous oxide reductase, trigger a shift from denitrification to dissimilatory nitrate reduction to ammonium (DNRA), or be used as electron donor for nitrate reduction. The goal of this study was to identify and isolate nitrate-reducing and denitrifying bacteria from the biofilter and to investigate their response to sulfide concentrations relevant for the system. Almost 500 nitrate-consuming isolates were screened by 16S rRNA gene-RFLP; for each RFLP pattern representatives were sequenced. In total, 40 different strains were identified, some of them novel species, mostly affiliating with Alphaproteobacteria but also including Beta- and Gammaproteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria. The diversity of the isolates was compared to the cultivation-independent diversity of nitrate-reducing and denitrifying bacteria based on narG and nosZ as functional marker genes. Growth experiments revealed great differences in sulfide-tolerance among isolates, ranging from < 50 µM to 5 mM; some strains were also able to oxidize sulfide. Increasing sulfide concentrations generally resulted in increased nitrous oxide production. Batch incubations of anaerobic sludge with 15N-nitrate confirmed the in situ relevance of these results and indicated a sulfide-induced shift from denitrification to DNRA.

  18. Centrifugal enrichment of sulfur isotopes

    International Nuclear Information System (INIS)

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

  19. Selection of denitrifying phosphorous accumulating organisms in IFAS systems: comparison of nitrite with nitrate as an electron acceptor.

    Science.gov (United States)

    Jabari, Pouria; Munz, Giulio; Oleszkiewicz, Jan A

    2014-08-01

    Nitrite and nitrate were compared as electron acceptors to select for denitrifying phosphorous accumulating organisms (DPAO) in two integrated fixed film activated sludge (IFAS 1 and IFAS 2) systems operated as sequencing batch reactors. The bench-scale experiment lasted one year and synthetic wastewater was used as feed. During anoxic conditions 20mgNO3(-)-NL(-1) were dosed into IFAS-1 and 20mgNO2(-)-NL(-1) were dosed into IFAS-2. Long term phosphorous and ammonia removal via nitritation were achieved in both systems and both attached and suspended biomass contributed to phosphorous and ammonia removal. DPAO showed no specific adaptation to the electron acceptor as evidenced by short term switch of feeding with nitrate or nitrite. Anoxic phosphorus uptake rate was significantly higher with nitrite than with nitrate. Results showed that DPAO activity with nitrite could be integrated into attached and suspended biomass of IFAS systems in long term operation. PMID:24873702

  20. Transitions in nirS-type Denitrifier Diversity, Community Composition, and Biogeochemical Activity along the Chesapeake Bay Estuary

    Directory of Open Access Journals (Sweden)

    ChristopherAFrancis

    2013-08-01

    Full Text Available Chesapeake Bay, the largest estuary in North America, can be characterized as having steep and opposing gradients in salinity and dissolved inorganic nitrogen along the main axis of the Bay. In this study, the diversity of nirS gene fragments (encoding cytochrome cd1-type nitrite reductase, physical/chemical parameters, and benthic N2-fluxes were analyzed in order to determine how denitrifier communities and biogeochemical activity vary along the estuary salinity gradient. The nirS gene fragments were PCR-amplified, cloned, and sequenced from sediment cores collected at five stations. Sequence analysis of 96 to 123 nirS clones from each station revealed extensive overall diversity in this estuary, as well as distinct spatial structure in the nirS sequence distributions. Both nirS-based richness and community composition varied among stations, with the most dramatic shifts occurring between low-salinity (oligohaline and moderate-salinity (mesohaline sites. For four samples collected in April, the nirS-based richness, nitrate concentrations, and N2-fluxes all decreased in parallel along the salinity gradient from the oligohaline northernmost station to the highest salinity (polyhaline station near the mouth of the Bay. The vast majority of the 550 nirS sequences were distinct from cultivated denitrifiers, although many were closely related to environmental clones from other coastal and estuarine systems. Interestingly, 8 of the 172 OTUs identified accounted for 42% of the total nirS clones, implying the presence of a few dominant and many rare genotypes, which were distributed in a non-random manner along the salinity gradient of Chesapeake Bay. These data, comprising the largest dataset to investigate nirS clone sequence diversity from an estuarine environment, also provided information that was required for the development of nirS microarrays to investigate the interaction of microbial diversity, environmental gradients, and biogeochemical activity.

  1. Whole-Genome Transcriptional Analysis of Chemolithoautotrophic Thiosulfate Oxidation by Thiobacillus denitrificans Under Aerobic vs. Denitrifying Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Beller, H R; Letain, T E; Chakicherla, A; Kane, S R; Legler, T C; Coleman, M A

    2006-04-22

    Thiobacillus denitrificans is one of the few known obligate chemolithoautotrophic bacteria capable of energetically coupling thiosulfate oxidation to denitrification as well as aerobic respiration. As very little is known about the differential expression of genes associated with ke chemolithoautotrophic functions (such as sulfur-compound oxidation and CO2 fixation) under aerobic versus denitrifying conditions, we conducted whole-genome, cDNA microarray studies to explore this topic systematically. The microarrays identified 277 genes (approximately ten percent of the genome) as differentially expressed using Robust Multi-array Average statistical analysis and a 2-fold cutoff. Genes upregulated (ca. 6- to 150-fold) under aerobic conditions included a cluster of genes associated with iron acquisition (e.g., siderophore-related genes), a cluster of cytochrome cbb3 oxidase genes, cbbL and cbbS (encoding the large and small subunits of form I ribulose 1,5-bisphosphate carboxylase/oxygenase, or RubisCO), and multiple molecular chaperone genes. Genes upregulated (ca. 4- to 95-fold) under denitrifying conditions included nar, nir, and nor genes (associated respectively with nitrate reductase, nitrite reductase, and nitric oxide reductase, which catalyze successive steps of denitrification), cbbM (encoding form II RubisCO), and genes involved with sulfur-compound oxidation (including two physically separated but highly similar copies of sulfide:quinone oxidoreductase and of dsrC, associated with dissimilatory sulfite reductase). Among genes associated with denitrification, relative expression levels (i.e., degree of upregulation with nitrate) tended to decrease in the order nar > nir > nor > nos. Reverse transcription, quantitative PCR analysis was used to validate these trends.

  2. Characterization of a murine neuron-enriched model of primary trigeminal ganglia cultures to study the interferon- ? antiviral effect against Herpes Simplex Virus type 1 / Caracterización de un modelo murino de cultivos primarios de ganglio trigeminal enriquecido en neuronas para el estudio del efecto antiviral del interferón- ? frente al virus Herpes simple tipo 1

    Scientific Electronic Library Online (English)

    Ana Maria, Low-Calle; Jeanette, Prada-Arismendy; Jaime E., Castellanos.

    2014-06-01

    Full Text Available Objetivo: Caracterizar un cultivo primario de ganglio trigeminal (GT) enriquecido en neuronas y evaluar la expresión de interferón- y su actividad frente a la infección con Herpes simple tipo 1 (HSV-1). Materiales y métodos: El porcentaje de neuronas fue determinado por inmunocitoquímica para neurof [...] ilamento. Los cultivos fueron tratados con interferón- ? e infectados con HSV-1, y se cuantificaron las células positivas para antígeno viral por inmunocitoquímica y la expresión de interferón- ? por PCR cuantitativa. Resultados: El cultivo presentó un 15% de neuronas y 85% de células no neuronales. Se encontró efecto citopático, asociado a una alta diseminación de la infección (72,9% neuronas y 48,3% de células no neuronales positivas para antígeno viral). El interferón- ? evitó la aparición de efecto citopático y disminuyó las células infectadas a 16,7% en neuronas y a 7,8% las células no neuronales. La infección viral incrementó la expresión de transcritos de interferón- ? 18,2 veces a las 6 h de infección, mientras que a las 18 h post infección el tratamiento con interferón incrementó esta expresión 3,7 veces. Discusión: Los cultivos presentaron un 15% de neuronas, lo cual es 10 veces más que en otros cultivos reportados. Las células no neuronales representan el 85% de las células del cultivo, y se evidenció que todos los tipos de células se infectaron; similar a lo que ha sido reportado durante infecciones agudas in vivo . Adicionalmente, el interferón- ? disminuyó el porcentaje de células infectadas y evitó la aparición de efecto citopático, similar a lo que ha sido reportado en cultivos de GT porcino. Conclusiones: Se caracterizó un modelo de cultivo primario de GT enriquecido en neuronas. Interferón- ? protegió las células del efecto citopático y la diseminación viral mientras que la infección viral incrementó la expresión de interferón- ?. Por lo tanto, el interferón- ? ejerció un papel antiviral importante frente al HSV-1 en estos cultivos. Abstract in english Objective: To characterize a neuron-enriched primary TG culture and evaluate interferon- ? expression and activity after HSV-1 infection. Materials and methods: The percentage of neurons present in cultures was assessed by neurofilament immunocytochemistry. Cultures were treated with interferon- ? a [...] nd infected with HSV-1, then viral antigen positive cells were counted and interferon- ?expression was assessed by quantitative PCR. Results: The culture contained 15% neurons and 85% non-neuronal cells. A cytopathic effect was observed, associated with high viral spread (72.9% neurons and 48.3% non-neuronal cells were positive for viral antigen). Interferon- ? treatment impaired the cytopathic effect and decreased the infected neurons to 16.7% and infected non-neuronal cells to 7.8%. Viral infection at 6 h postinfection significantly increased the interferon- ? transcripts by 18.2 fold, while at 18 h postinfection Interferon pre-treatment in infected cultures increased interferon- ? transcription by 3.7 fold. Discussion: This culture model contained 15% neurons, which is 10 times higher compared to other reported cultures, and non-neuronal cells comprised 85% of cells in this culture. All types of cells were found to be infected, which is similar to that reported during acute infections in vivo . Additionally, interferon- ?decreased the infected cells, avoiding the cytopathic effect, which is similar to that reported in swine TG cultures. Conclusions: A neuron-enriched primary TG model was characterized. Interferon- ? treatment protected cells from cytopathic effects and viral spread, while viral infection up-regulated interferon- ? expression. This result means that interferon- ? exerts an important antiviral effect against HSV-1 in these cultures.

  3. Fostering Earth Science Inquiry From Within a Native Hawaiian Cultural Framework In O`ahu (Hawai`i) Through A Multidisciplinary Place-Based High School Summer Enrichment Program

    Science.gov (United States)

    Moxey, L.; Dias, R.; Legaspi, E.

    2010-12-01

    During the summer of 2010, twenty-five public high school students from underrepresented communities and ethnicities (Hawaiian, part-Hawaiian, S?moan, Filipino, Pacific Islander) in O`ahu (Hawai`i) participated in the M?lama Ke Ahupua`a (protecting our watershed) program. This rigorous three-week hands-on, place-based multidisciplinary program provided students with the opportunity of visiting the M?noa Valley watershed (O`ahu, Hawaii) for learning and experiencing the Earth Science System dynamics that comprises it, while simultaneously exploring the significance of the ahupua`a (watershed) as related to native Hawaiian history and culture. While earning Hawaii DOE-approved academic credit, students utilized GPS/GIS technology, quantitative water quality testing equipment, and environmental monitoring tools for performing a watershed survey and water quality study of M?noa Stream (M?noa Valley) from its inception in the mountains, its advance through Honolulu’s urbanized areas, and its convergence with the Pacific Ocean. Through this hands-on field-based study, students documented changes in the watershed’s environment as reflected in declining water quality induced by anthropogenic pollution sources and urbanization. Students also visited relevant native Hawaiian cultural sites in M?noa, and explored their direct links with the historical sustainable usage of the watershed’s natural resources, both from a cultural and science-based perspective. Finally, traditional wa`a (native Hawaiian outrigger canoes) were used as both cultural resources for discussing ancient Polynesian exploration, as well as scientific research platforms for conducting near-shore reef surveys & assessments. This program served to promote not only Earth Science literacy and STEM skills, but also contributed to further environmental stewardship while fostering native Hawaiian & Polynesian cultural identities.

  4. Uranium enrichment by gas centrifuge

    International Nuclear Information System (INIS)

    After recalling the physical principles and the techniques of centrifuge enrichment the report describes the centrifuge enrichment programmes of the various countries concerned and compares this technology with other enrichment technologies like gaseous diffusion, laser, aerodynamic devices and chemical processes. The centrifuge enrichment process is said to be able to replace with advantage the existing enrichment facilities in the short and medium term. Future prospects of the process are also described, like recycled uranium enrichment and economic improvements; research and development needs to achieve the economic prospects are also indicated. Finally the report takes note of the positive aspect of centrifuge enrichment as far as safeguards and nuclear safety are concerned. 27 figs, 113 refs

  5. Modular enrichment measurement system for in-situ enrichment assay

    International Nuclear Information System (INIS)

    A modular enrichment measurement system has been designed and is in operation within General Electric's Nuclear Fuel Fabrication Facility for the in-situ enrichment assay of uranium-bearing materials in process containers. This enrichment assay system, which is based on the ''enrichment meter'' concept, is an integral part of the site's enrichment control program and is used in the in-situ assay of the enrichment of uranium dioxide (UO2) powder in process containers (five gallon pails). The assay system utilizes a commercially available modular counting system and a collimnator designed for compatability with process container transport lines and ease of operator access. The system has been upgraded to include a microprocessor-based controller to perform system operation functions and to provide data acquisition and processing functions. Standards have been fabricated and qualified for the enrichment assay of several types of uranium-bearing materials, including UO2 powders. The assay system has performed in excess of 20,000 enrichment verification measurements annually and has significantly contributed to the facility's enrichment control program

  6. Enrichment of boron 10

    International Nuclear Information System (INIS)

    A isotopic separation pilot plant with five ion exchange columns interconnected in series were designed and built in the IEN. The columns are charged with a strong anionic resin in its alkaline form. The boric acid solution is introduced in the separation columns until it reaches a absorbing zone length which is sufficient to obtain the desired boron-10 isotopic concentration. The boric acid absorbing zone movement is provided by the injection of a diluted hydrochloric acid solution, which replace the boric acid throughout the columns. The absorbing zone equilibrium length is proportional to its total length. The enriched boron-10 and the depleted boron are located in the final boundary and in the initial position of the absorbing zones, respectively. (author)

  7. Evaluation of the microbial diversity in sequencing batch reactor treating linear alkylbenzene sulfonate under denitrifying and mesophilic conditions using swine sludge as inoculum

    Scientific Electronic Library Online (English)

    Iolanda Cristina Silveira, Duarte; Lorena Lima de, Oliveira; Dagoberto Yukio, Okada; Pierre Ferreira do, Prado; Maria Bernadete Amâncio, Varesche.

    Full Text Available The objective of this study was to evaluate the degradation of Linear Alkylbenzene Sulfonate (LAS) in anaerobic sequencing batch reactor (ASBR) under denitrifying conditions using swine sludge as inoculum. The reactor was operated for 104 days with synthetic substrate containing nitrate, and LAS was [...] added later (22 mg/L). Considering the added mass of the LAS, the adsorbed mass in the sludge and discarded along with the effluent, degradation of the surfactant at the end of operation was 87%, removal of chemical oxygen demand was 86% and nitrate was 98%. The bacterial community was evaluated by cutting the bands and sequencing of polymerase chain reaction (PCR) fragments and denaturing gradient gel electrophoresis (DGGE). The sequences obtained were related to the phylum Proteobacteria and the alpha-and beta-proteobacteria classes, these bacteria were probably involved in the degradation of LAS. The efficiently degraded LAS in the reactor was operated in batch sequences in denitrifying conditions.

  8. Effects of Heavy Metal Contamination upon Soil Microbes: Lead-induced Changes in General and Denitrifying Microbial Communities as Evidenced by Molecular Markers

    Directory of Open Access Journals (Sweden)

    Maria Begonia

    2008-12-01

    Full Text Available Lead (Pb is a common environmental contaminant found in soils. Unlike other metals, Pb has no biological role, and is potentially toxic to microorganisms. Effects of low (1 ppm and high (500-2000 levels of lead (Pb upon the soil microbial community was investigated by the PCR/DGGE analysis of the 16S and nirK gene markers, indicative of general microbial community and denitrifying community, respectively. Community analysis by use of those markers had shown that Pb has detectable effects upon the community diversity even at the lowest concentration tested. Analysis of sample diversity and similarity between the samples suggested that there are several thresholds crossed as metal concentration increase, each causing a substantial change in microbial diversity. Preliminary data obtained in this study suggest that the denitrifying microbial community adapts to elevated levels of Pb by selecting for metal-resistant forms of nitrite reductases.

  9. Evaluation of the microbial diversity in sequencing batch reactor treating linear alkylbenzene sulfonate under denitrifying and mesophilic conditions using swine sludge as inoculum

    Scientific Electronic Library Online (English)

    Iolanda Cristina Silveira, Duarte; Lorena Lima de, Oliveira; Dagoberto Yukio, Okada; Pierre Ferreira do, Prado; Maria Bernadete Amâncio, Varesche.

    2015-06-01

    Full Text Available The objective of this study was to evaluate the degradation of Linear Alkylbenzene Sulfonate (LAS) in anaerobic sequencing batch reactor (ASBR) under denitrifying conditions using swine sludge as inoculum. The reactor was operated for 104 days with synthetic substrate containing nitrate, and LAS was [...] added later (22 mg/L). Considering the added mass of the LAS, the adsorbed mass in the sludge and discarded along with the effluent, degradation of the surfactant at the end of operation was 87%, removal of chemical oxygen demand was 86% and nitrate was 98%. The bacterial community was evaluated by cutting the bands and sequencing of polymerase chain reaction (PCR) fragments and denaturing gradient gel electrophoresis (DGGE). The sequences obtained were related to the phylum Proteobacteria and the alpha-and beta-proteobacteria classes, these bacteria were probably involved in the degradation of LAS. The efficiently degraded LAS in the reactor was operated in batch sequences in denitrifying conditions.

  10. Advanced Neutron Source enrichment study

    International Nuclear Information System (INIS)

    A study has been performed of the impact on performance of using low enriched uranium (20% 235U) or medium enriched uranium (35% 235U) as an alternative fuel for the Advanced Neutron Source, which is currently designed to use uranium enriched to 93% 235U. Higher fuel densities and larger volume cores were evaluated at the lower enrichments in terms of impact on neutron flux, safety, safeguards, technical feasibility, and cost. The feasibility of fabricating uranium silicide fuel at increasing material density was specifically addressed by a panel of international experts on research reactor fuels. The most viable alternative designs for the reactor at lower enrichments were identified and discussed. Several sensitivity analyses were performed to gain an understanding of the performance of the reactor at parametric values of power, fuel density, core volume, and enrichment that were interpolations between the boundary values imposed on the study or extrapolations from known technology

  11. Enrichment promotes learning in fish

    OpenAIRE

    Strand, David A.; Utne-Palm, Anne C.; Jakobsen, Per J.; Braithwaite, Victoria A.; Jensen, Knut Helge; Salvanes, Anne Gro Vea

    2010-01-01

    Captive birds and mammals reared in enriched rearing environments have been shown to behave more flexibly compared to animals reared in impoverished or plain environments. Recent evidence has shown that this is also true for fish; enrichment promotes faster recovery after a stressful experience, a higher propensity for exploration of novel areas and the development of more sophisticated social behaviour. Here we report how enrichment influences social learning in juvenile cod G...

  12. Abundance and Diversity of Bacterial Nitrifiers and Denitrifiers and Their Functional Genes in Tannery Wastewater Treatment Plants Revealed by High-Throughput Sequencing

    OpenAIRE

    Wang, Zhu; Zhang, Xu-Xiang; LU, Xin; LIU, Bo; LI, YAN; Long, Chao; Li, Aimin

    2014-01-01

    Biological nitrification/denitrification is frequently used to remove nitrogen from tannery wastewater containing high concentrations of ammonia. However, information is limited about the bacterial nitrifiers and denitrifiers and their functional genes in tannery wastewater treatment plants (WWTPs) due to the low-throughput of the previously used methods. In this study, 454 pyrosequencing and Illumina high-throughput sequencing, combined with molecular methods, were used to comprehensively ch...

  13. Heat Production by the Denitrifying Bacterium Pseudomonas fluorescens and the Dissimilatory Ammonium-Producing Bacterium Pseudomonas putrefaciens during Anaerobic Growth with Nitrate as the Electron Acceptor

    OpenAIRE

    Samuelsson, M.-O.; Cadez, P.; Gustafsson, L.

    1988-01-01

    The heat production rate and the simultaneous nitrate consumption and production and consumption of nitrite and nitrous oxide were monitored during the anaerobic growth of two types of dissimilatory nitrate reducers. Pseudomonas fluorescens, a denitrifier, consumed nitrate and accumulated small amounts of nitrite or nitrous oxide. The heat production rate increased steadily during the course of nitrate consumption and decreased rapidly concomitant with the depletion of the electron acceptors....

  14. Insights into the effect of soil pH on N2O and N2 emissions and denitrifier community size and activity.

    Czech Academy of Sciences Publication Activity Database

    ?uhel, Ji?í; Šimek, Miloslav; Laughlin, R.J.; Bru, D.; Chéneby, D.; Watson, C.J.; Philippot, L.

    2010-01-01

    Ro?. 76, ?. 6 (2010), s. 1870-1878. ISSN 0099-2240 R&D Projects: GA MŠk MEB020726; GA MŠk LC06066; GA AV ?R IAA600660605 Institutional research plan: CEZ:AV0Z60660521 Keywords : soil pH * N 2 O and N 2 emissions * denitrifier community Subject RIV: EH - Ecology, Behaviour Impact factor: 3.778, year: 2010

  15. Abundance and Diversity of Bacterial Nitrifiers and Denitrifiers and Their Functional Genes in Tannery Wastewater Treatment Plants Revealed by High-Throughput Sequencing

    Science.gov (United States)

    Wang, Zhu; Zhang, Xu-Xiang; Lu, Xin; Liu, Bo; Li, Yan; Long, Chao; Li, Aimin

    2014-01-01

    Biological nitrification/denitrification is frequently used to remove nitrogen from tannery wastewater containing high concentrations of ammonia. However, information is limited about the bacterial nitrifiers and denitrifiers and their functional genes in tannery wastewater treatment plants (WWTPs) due to the low-throughput of the previously used methods. In this study, 454 pyrosequencing and Illumina high-throughput sequencing, combined with molecular methods, were used to comprehensively characterize structures and functions of nitrification and denitrification bacterial communities in aerobic and anaerobic sludge of two full-scale tannery WWTPs. Pyrosequencing of 16S rRNA genes showed that Proteobacteria and Synergistetes dominated in the aerobic and anaerobic sludge, respectively. Ammonia-oxidizing bacteria (AOB) amoA gene cloning revealed that Nitrosomonas europaea dominated the ammonia-oxidizing community in the WWTPs. Metagenomic analysis showed that the denitrifiers mainly included the genera of Thauera, Paracoccus, Hyphomicrobium, Comamonas and Azoarcus, which may greatly contribute to the nitrogen removal in the two WWTPs. It is interesting that AOB and ammonia-oxidizing archaea had low abundance although both WWTPs demonstrated high ammonium removal efficiency. Good correlation between the qPCR and metagenomic analysis is observed for the quantification of functional genes amoA, nirK, nirS and nosZ, indicating that the metagenomic approach may be a promising method used to comprehensively investigate the abundance of functional genes of nitrifiers and denitrifiers in the environment. PMID:25420093

  16. Effects of warming and drought on potential N2O emissions and denitrifying bacteria abundance in grasslands with different land-use.

    Science.gov (United States)

    Keil, Daniel; Niklaus, Pascal A; von Riedmatten, Lars R; Boeddinghaus, Runa S; Dormann, Carsten F; Scherer-Lorenzen, Michael; Kandeler, Ellen; Marhan, Sven

    2015-07-01

    Increased warming in spring and prolonged summer drought may alter soil microbial denitrification. We measured potential denitrification activity and denitrifier marker gene abundances (nirK, nirS, nosZ) in grasslands soils in three geographic regions characterized by site-specific land-use indices (LUI) after warming in spring, at an intermediate sampling and after summer drought. Potential denitrification was significantly increased by warming, but did not persist over the intermediate sampling. At the intermediate sampling, the relevance of grassland land-use intensity was reflected by increased potential N2O production at sites with higher LUI. Abundances of total bacteria did not respond to experimental warming or drought treatments, displaying resilience to minor and short-term effects of climate change. In contrast, nirS- and nirK-type denitrifiers were more influenced by drought in combination with LUI and pH, while the nosZ abundance responded to the summer drought manipulation. Land-use was a strong driver for potential denitrification as grasslands with higher LUI also had greater potentials for N2O emissions. We conclude that both warming and drought affected the denitrifying communities and the potential denitrification in grassland soils. However, these effects are overruled by regional and site-specific differences in soil chemical and physical properties which are also related to grassland land-use intensity. PMID:26092950

  17. The activity and community structure of total bacteria and denitrifying bacteria across soil depths and biological gradients in estuary ecosystem.

    Science.gov (United States)

    Lee, Seung-Hoon; Kang, Hojeong

    2016-02-01

    The distribution of soil microorganisms often shows variations along soil depth, and even in the same soil layer, each microbial group has a specific niche. In particular, the estuary soil is intermittently flooded, and the characteristics of the surface soil layer are different from those of other terrestrial soils. We investigated the microbial community structure and activity across soil depths and biological gradients composed of invasive and native plants in the shallow surface layer of an estuary ecosystem by using molecular approaches. Our results showed that the total and denitrifying bacterial community structures of the estuarine wetland soil differed according to the short depth gradient. In growing season, gene copy number of 16S rRNA were 1.52(±0.23) × 10(11), 1.10(±0.06) × 10(11), and 4.33(±0.16) × 10(10) g(-1) soil; nirS were 5.41(±1.25) × 10(8), 4.93(±0.94) × 10(8), and 2.61(±0.28) × 10(8) g(-1) soil; and nirK were 9.67(±2.37) × 10(6), 3.42(±0.55) × 10(6), and 2.12(±0.19) × 10(6) g(-1) soil in 0 cm, 5 cm, and 10 cm depth layer, respectively. The depth-based difference was distinct in the vegetated sample and in the growing season, evidencing the important role of plants in structuring the microbial community. In comparison with other studies, we observed differences in the microbial community and functions even across very short depth gradients. In conclusion, our results suggested that (i) in the estuary ecosystem, the denitrifying bacterial community could maintain its abundance and function within shallow surface soil layers through facultative anaerobiosis, while the total bacterial community would be both quantitatively and qualitatively affected by the soil depth, (ii) the nirS gene community, rather than the nirK one, should be the first candidate used as an indicator of the microbial denitrification process in the estuary system, and (iii) as the microbial community is distributed and plays a certain niche role according to biogeochemical factors, the study of the microbial community even in surface soil should be performed in detail by considering the soil depth. PMID:26526456

  18. Nitrogen Removal by a Fungal Aerobic Denitrifier of Penicillium Strain

    OpenAIRE

    Chaocheng Zhao; Weisi Li

    2012-01-01

    A kind of aerobic Penicillium that can remove ammonia, nitrite and nitrate was isolated through an improved bromothymol blue (BTB) selective culture medium method in this experiment and then the nitrogen removal by the strain was detailedly investigated. The results showed that this strain was able to make use of many kinds of organic carbon compounds as sole carbon source for the removal of the three types of inorganic nitrogen compounds but the way of removal was different. Ammonia was assi...

  19. Earthquake forecast enrichment scores

    Directory of Open Access Journals (Sweden)

    Christine Smyth

    2012-03-01

    Full Text Available The Collaboratory for the Study of Earthquake Predictability (CSEP is a global project aimed at testing earthquake forecast models in a fair environment. Various metrics are currently used to evaluate the submitted forecasts. However, the CSEP still lacks easily understandable metrics with which to rank the universal performance of the forecast models. In this research, we modify a well-known and respected metric from another statistical field, bioinformatics, to make it suitable for evaluating earthquake forecasts, such as those submitted to the CSEP initiative. The metric, originally called a gene-set enrichment score, is based on a Kolmogorov-Smirnov statistic. Our modified metric assesses if, over a certain time period, the forecast values at locations where earthquakes have occurred are significantly increased compared to the values for all locations where earthquakes did not occur. Permutation testing allows for a significance value to be placed upon the score. Unlike the metrics currently employed by the CSEP, the score places no assumption on the distribution of earthquake occurrence nor requires an arbitrary reference forecast. In this research, we apply the modified metric to simulated data and real forecast data to show it is a powerful and robust technique, capable of ranking competing earthquake forecasts.

  20. Enrichment operations outlook

    International Nuclear Information System (INIS)

    The U. S. gaseous diffusion plants have achieved an admirable record of performance and reliability, and there is confidence it can be maintained through the rest of this century. In addition to aggressive regular maintenance, three specific programs are combined to maximize the reliability of the plants: A Deferred Maintenance Program to restore production equipment and associated auxiliary systems; a Cascade Improvement Program (CIP) to install new and improved technology such as rebuilt and more efficient compressors, piping and control valves with better aerodynamic characteristics, and new and improved barrier; and a Cascade Uprating Program (CUP) to refurbish and add capacity to electrical and process cooling systems. A three-plant steering committee has been formed to examine in detail all aspects of enrichment facilities not already covered by these three specific programs, and task forces have been assigned to investigate in depth long-term reliability in these areas. In many cases, specific testing programs have been designed to evaluate the potential life of components, and information from commercial industries is routinely used. Where deficiencies are found, capital budget items are submitted and corrective action planned. Existing experience is available to those industries concerned with new plant ventures, and the Industrial Participation Program is one example where private industry can take full advantage of this existing experience. (U.S.)

  1. Uranium enrichment and weapon proliferation

    International Nuclear Information System (INIS)

    The internationalization of the commercial enrichment industry under a unified authority is recommended. This would guarantee fuel supplies to all countries at fair prices, could arrange for equitable compensation of states with existing enrichment capabilities, and could enforce non-proliferation measures. (U.K.)

  2. Work Enrichment for Academic Libraries.

    Science.gov (United States)

    Martell, Charles; Untawale, Mercedes

    1983-01-01

    Explores important quality of work life strategy--job redesign--and discusses job enlargement and job enrichment. A case study of academic library personnel demonstrates how introduction of automated systems at University of California, Berkeley led to restructuring and enrichment of jobs. References and list of selected resources are appended.…

  3. Process evaluation by isotope enrichment

    International Nuclear Information System (INIS)

    An evaluation of an engineering or biological process or system can be made by treating the system with an isotopically-enriched substance which flows through the system intact or which is changed into another substance containing isotope-enrichment, and a gaseous sample thereof is analyzed at low pressure e.g. by infra-red spectroscopy to measure the intensity of a specific absorption line of the enriched isotopic species whereby the concentration of the species is calculated. The enrichment of the measured species furnishes information about the functioning of the process. In bio-medical testing, the tracer isotopic species used frequently are enriched values of CO, CO2, H2O or NH3 in the breath or derived from tissues or other specimens. (author)

  4. Importance of pre-enrichment media for isolation of Salmonella spp. from swine and poultry

    DEFF Research Database (Denmark)

    Hoorfar, Jeffrey; Baggesen, Dorte Lau

    1998-01-01

    The performance of two new (1-day) culture methods, Salmonella Enrichment Broth (SEB) and Revive, and an alternative pre-enrichment broth, designated Universal pre-enrichment broth (UB), was compared to the internationally accepted buffered peptone water (BPW). The study was directed towards detection of Salmonella in 100 faecal samples from porcine and 100 neck-skin samples from poultry. The sensitivity (number of positive cases per method among all the positive cases) of the conventional pre-e...

  5. 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...

  6. New generation enrichment monitoring technology for gas centrifuge enrichment plants

    Energy Technology Data Exchange (ETDEWEB)

    Ianakiev, Kiril D [Los Alamos National Laboratory; Alexandrov, Boian S. [Los Alamos National Laboratory; Boyer, Brian D. [Los Alamos National Laboratory; Hill, Thomas R. [Los Alamos National Laboratory; Macarthur, Duncan W. [Los Alamos National Laboratory; Marks, Thomas [Los Alamos National Laboratory; Moss, Calvin E. [Los Alamos National Laboratory; Sheppard, Gregory A. [Los Alamos National Laboratory; Swinhoe, Martyn T. [Los Alamos National Laboratory

    2008-06-13

    The continuous enrichment monitor, developed and fielded in the 1990s by the International Atomic Energy Agency, provided a go-no-go capability to distinguish between UF{sub 6} containing low enriched (approximately 4% {sup 235}U) and highly enriched (above 20% {sup 235}U) uranium. This instrument used the 22-keV line from a {sup 109}Cd source as a transmission source to achieve a high sensitivity to the UF{sub 6} gas absorption. The 1.27-yr half-life required that the source be periodically replaced and the instrument recalibrated. The instrument's functionality and accuracy were limited by the fact that measured gas density and gas pressure were treated as confidential facility information. The modern safeguarding of a gas centrifuge enrichment plant producing low-enriched UF{sub 6} product aims toward a more quantitative flow and enrichment monitoring concept that sets new standards for accuracy stability, and confidence. An instrument must be accurate enough to detect the diversion of a significant quantity of material, have virtually zero false alarms, and protect the operator's proprietary process information. We discuss a new concept for advanced gas enrichment assay measurement technology. This design concept eliminates the need for the periodic replacement of a radioactive source as well as the need for maintenance by experts. Some initial experimental results will be presented.

  7. [Influences of long-term application of organic and inorganic fertilizers on the composition and abundance of nirS-type denitrifiers in black soil].

    Science.gov (United States)

    Yin, Chang; Fan, Fen-Liang; Li, Zhao-Jun; Song, A-Lin; Zhu, Ping; Peng, Chang; Liang, Yong-Chao

    2012-11-01

    The objectives of this study were to explore the effects of long-term organic and inorganic fertilizations on the composition and abundance of nirS-type denitrifiers in black soil. Soil samples were collected from 4 treatments (i. e. no fertilizer treatment, CK; organic manure treatment, OM; chemical fertilizer treatment (NPK) and combination of organic and chemical fertilizers treatment (MNPK)) in Gongzhuling Long-term Fertilization Experiment Station. Composition and abundance of nirS-type denitrifiers were analyzed with terminal restriction fragment length polymorphism (T-RFLP) and real-time quantitative PCR (Q-PCR), respectively. Denitrification enzyme activity (DEA) and soil properties were also measured. Application of organic fertilizers (OM and MNPK) significantly increased the DEAs of black soil, with the DEAs in OM and MNPK being 5.92 and 6.03 times higher than that in CK treatment, respectively, whereas there was no significant difference between NPK and CK. OM and MNPK treatments increased the abundances of nirS-type denitrifiers by 2.73 and 3.83 times relative to that of CK treatment, respectively. The abundance of nirS-type denitrifiers in NPK treatment was not significantly different from that of CK. The T-RFLP analysis of nirS genes showed significant differences in community composition between organic and inorganic treatments, with the emergence of a 79 bp T-RF, a significant decrease in relative abundance of the 84 bp T-RF and a loss of the 99 bp T-RF in all organic treatments. Phylogenetic analysis indicated that the airS-type denitrifiers in the black soil were mainly composed of alpha, beta and gamma-Proteobacteria. The 79 bp-type denitrifiers inhabiting exclusively in organic treatments (OM and MNPK) were affiliated to Pseudomonadaceae in gamma-Proteobacteria and Burkholderiales in beta-Proteobacteria. The 84 bp-types were related to Burkholderiales and Rhodocyclales. Correlation analysis indicated that pH, concentrations of total nitrogen (TN), total phosphorus (TP), total organic carbon (TOC), nitrate (NO3(-) -N) and ammonia (NH4(+) -N) were significantly related to abundances of nirS-denitrifers (r = 0.724-0.922, P < 0.05) and the DEA (r = 0.453-0.938, P < 0.01). In addition, the DEAs were linearly and positively correlated with the abundances of nirS-type denitrifers (r = 0.85, P < 0.01). Redundancy analysis showed that except moisture, pH and concentrations of TP, TP, TOC, NH4(+) -N and NO3(-) -N were significantly correlated with the community structure of nirS-type denirifiers (r = 0.440-0.862, P < 0.01). Furthermore, the DEAs were significantly correlated with the compositions of nirS-denirifiers (r = 0.863, P < 0.01). In conclusion, the airS-type denitrifiers in the black soil are more responsive to the organic treatments than to the inorganic treatments in terms of community composition and abundance, both of which are correlated with the changes of DEAs. PMID:23323433

  8. Changes in bacterial community structure correlate with initial operating conditions of a field-scale denitrifying fluidized bed reactor.

    Science.gov (United States)

    Hwang, C; Wu, W-M; Gentry, T J; Carley, J; Carroll, S L; Schadt, C; Watson, D; Jardine, P M; Zhou, J; Hickey, R F; Criddle, C S; Fields, M W

    2006-08-01

    High levels of nitrate are present in groundwater migrating from the former waste disposal ponds at the Y-12 National Security Complex in Oak Ridge, TN. A field-scale denitrifying fluidized bed reactor (FBR) was designed, constructed, and operated with ethanol as an electron donor for the removal of nitrate. After inoculation, biofilms developed on the granular activated carbon particles. Changes in the bacterial community of the FBR were evaluated with clone libraries (n = 500 partial sequences) of the small-subunit rRNA gene for samples taken over a 4-month start-up period. Early phases of start-up operation were characterized by a period of selection, followed by low diversity and predominance by Azoarcus-like sequences. Possible explanations were high pH and nutrient limitations. After amelioration of these conditions, diversification increased rapidly, with the appearance of Dechloromonas, Pseudomonas, and Hydrogenophaga sequences. Changes in NO3, SO4, and pH also likely contributed to shifts in community composition. The detection of sulfate-reducing-bacteria-like sequences closely related to Desulfovibrio and Desulfuromonas in the FBR have important implications for downstream applications at the field site. PMID:16292532

  9. Isolation and Characterization of Novel Denitrifying Bacterium Geobacillus sp. SG-01 Strain from Wood Chips Composted with Swine Manure.

    Science.gov (United States)

    Yang, Seung-Hak; Cho, Jin-Kook; Lee, Soon-Youl; Abanto, Oliver D; Kim, Soo-Ki; Ghosh, Chiranjit; Lim, Joung-Soo; Hwang, Seong-Gu

    2013-11-01

    Nitrate contamination in ground and surface water is an increasingly serious environmental problem and only a few bacterial strains have been identified that have the ability to remove nitrogen pollutants from wastewater under thermophilic conditions. We therefore isolated thermophilic facultative bacterial strains from wood chips that had been composted with swine manure under aerated high temperature conditions so as to identify strains with denitrifying ability. Nine different colonies were screened and 3 long rod-shaped bacterial strains designated as SG-01, SG-02, and SG-03 were selected. The strain SG-01 could be differentiated from SG-02 and SG-03 on the basis of the method that it used for sugar utilization. The 16S rRNA genes of this strain also had high sequence similarity with Geobacillus thermodenitrificans 465(T) (99.6%). The optimal growth temperatures (55°C), pH values (pH 7.0), and NaCl concentrations (1%) required for the growth of strain SG-01 were established. This strain reduced 1.18 mM nitrate and 1.45 mM nitrite in LB broth after 48 h of incubation. These results suggest that the G. thermodenitrificans SG-01 strain may be useful in the removal of nitrates and nitrites from wastewater generated as a result of livestock farming. PMID:25049754

  10. Biodegradability of some nitrogenous heterocyclic compounds and co-degradation with phenol by denitrifiers in anoxic sludge reactor.

    Science.gov (United States)

    Wang, Zixing; Xu, Xiaochen; Yang, Fenglin; Tan, Zhongxia; Chen, Jie

    2015-01-01

    Phenol and nitrogenous heterocyclic compounds (NHCs) are typical organic pollutants in coal gasification wastewater which are difficult to deal with. Unlike phenol, the stable molecular structure of NHCs make them nearly impossible to degrade under aerobic or anaerobic condition. In this paper, biodegradation of phenol and NHCs as carbon sources for denitrification was studied in a laboratory-scale anoxic reactor. Denitrifiers could degrade 490 mg/L phenol and 321.5 mg/L NO3(-)-N within 12 hours with removal efficiencies of 99.8% and 99.6%, respectively. The inhibition of pyridine on the microbes could be reduced by adding phenol into influent and the experimental results showed that pyridine could be degraded as the sole carbon source with the maximum organic loading rate of 4.38 mg/(g MLSS·h) (MLSS: mixed liquor suspended solids). When phenol was included as a growth substrate, the degradation performance of quinoline and pyrrole was improved due to co-degradation, and removal rate of NHCs increased according with increment of phenol in influent. PMID:26204065

  11. Hydrogen-enriched fuels

    Energy Technology Data Exchange (ETDEWEB)

    Roser, R. [NRG Technologies, Inc., Reno, NV (United States)

    1998-08-01

    NRG Technologies, Inc. is attempting to develop hardware and infrastructure that will allow mixtures of hydrogen and conventional fuels to become viable alternatives to conventional fuels alone. This commercialization can be successful if the authors are able to achieve exhaust emission levels of less than 0.03 g/kw-hr NOx and CO; and 0.15 g/kw-hr NMHC at full engine power without the use of exhaust catalysts. The major barriers to achieving these goals are that the lean burn regimes required to meet exhaust emissions goals reduce engine output substantially and tend to exhibit higher-than-normal total hydrocarbon emissions. Also, hydrogen addition to conventional fuels increases fuel cost, and reduces both vehicle range and engine output power. Maintaining low emissions during transient driving cycles has not been demonstrated. A three year test plan has been developed to perform the investigations into the issues described above. During this initial year of funding research has progressed in the following areas: (a) a cost effective single-cylinder research platform was constructed; (b) exhaust gas speciation was performed to characterize the nature of hydrocarbon emissions from hydrogen-enriched natural gas fuels; (c) three H{sub 2}/CH{sub 4} fuel compositions were analyzed using spark timing and equivalence ratio sweeping procedures and finally; (d) a full size pick-up truck platform was converted to run on HCNG fuels. The testing performed in year one of the three year plan represents a baseline from which to assess options for overcoming the stated barriers to success.

  12. Mineralization of Diethylthiophosphoric Acid by an Enriched Consortium from Cattle Dip

    OpenAIRE

    Shelton, Daniel R.

    1988-01-01

    Enrichment cultures were initiated from cattle dip solution with diethylthiophosphoric acid (DETP) as the carbon and energy source. An enriched consortium consisting of at least six distinct bacterial species was subsequently obtained. The consortium mineralized DETP to sulfate and phosphate while utilizing ethyl moieties as a carbon and energy source. These data demonstrate that DETP can be metabolized under environmentally realistic conditions.

  13. New primers for detecting and quantifying denitrifying anaerobic methane oxidation archaea in different ecological niches.

    Science.gov (United States)

    Ding, Jing; Ding, Zhao-Wei; Fu, Liang; Lu, Yong-Ze; Cheng, Shuk H; Zeng, Raymond J

    2015-11-01

    The significance of ANME-2d in methane sink in the environment has been overlooked, and there was no any study evaluating the distribution of ANME-2d in the environment. New primers were thus needed to be designed for following research. In this paper, a pair of primers (DP397F and DP569R) was designed to quantify ANME-2d. The specificity and amplification efficiency of this primer pair were acceptable. PCR amplification of another pair of primers (DP142F and DP779R) generated a single, bright targeted band from the enrichment sample, but yielded faint, multiple bands from the environmental samples. Nested PCR was conducted using the primers DP142F/DP779R in the first round and DP142F/DP569R in the second round, which generated a bright targeted band. Further phylogenetic analysis showed that these targeted bands were ANME-2d-related sequences. Real-time PCR showed that the copies of the 16s ribosomal RNA gene of ANME-2d in these samples ranged from 3.72 × 10(4) to 2.30 × 10(5) copies ?g(-1) DNA, indicating that the percentage of ANME-2d was greatest in a polluted river sample and least in a rice paddy sample. These results demonstrate that the newly developed real-time PCR primers could sufficiently quantify ANME-2d and that nested PCR with an appropriate combination of the new primers could successfully detect ANME-2d in environmental samples; the latter finding suggests that ANME-2d may spread in environments. PMID:26300291

  14. High enrichment to low enrichment core's conversion. Technical securities

    International Nuclear Information System (INIS)

    This work presents the fulfillment of the technical securities subscribed by INVAP S.E. for the conversion of a high enriched uranium core. The reactor (of 5 thermal Mw), built in the 50's and 60's, is of the 'swimming pool' type, with light water and fuel elements of the curve plates MTR type, enriched at 93.15 %. These are neutronic and thermohydraulic securities. (Author)

  15. High enrichment to low enrichment core's conversion. Accidents analysis

    International Nuclear Information System (INIS)

    This work analyzes the different accidents that may occur in the reactor's facility after the 20% high-enriched uranium core's conversion. The reactor (of 5 thermal Mw), built in the 50's and 60's, is of the 'swimming pool' type, with light water and fuel elements of the curve plates MTR type, enriched at 93.15 %. This analysis includes: a) accidents by reactivity insertion; b) accidents by coolant loss; c) analysis by flow loss and d) fission products release. (Author)

  16. Poster 1. Enriched boron products

    International Nuclear Information System (INIS)

    Eagle-Picher can produce large quantities of isotopically enriched boron up to 99 at % boron 10. Two products are of particular interest for the water chemistry in nuclear reactors. Enriched sodium pentaborate can be stored in the standby liquid control tank of the boiling water reactors. It allows the operator to employ more active fuels and still have sufficient shut down capabilities. Enriched boric acid can be used as a chemical shim in the primary cooling system of pressurized water reactors. It provides the benefits associated with high pH without sacrificing the boron 10 content or increasing the lithium content. (author)

  17. Classification of positive blood cultures

    DEFF Research Database (Denmark)

    Gradel, Kim Oren; Knudsen, Jenny Dahl; Arpi, Magnus; Ostergaard, Christian; Schønheyder, Henrik C; Søgaard, Mette

    2012-01-01

    ABSTRACT: BACKGROUND: Information from blood cultures is utilized for infection control, public health surveillance, and clinical outcome research. This information can be enriched by physicians assessments of positive blood cultures, which are, however, often available from selected patient groups or pathogens only. The aim of this work was to determine whether patients with positive blood cultures can be classified effectively for outcome research in epidemiological studies by the use of admin...

  18. Rectoanal Mucosal Swab Culture Is More Sensitive Than Fecal Culture and Distinguishes Escherichia coli O157:H7-Colonized Cattle and Those Transiently Shedding the Same Organism

    OpenAIRE

    Rice, Daniel H.; Sheng, Haiqing Q.; Wynia, Stacey A.; Carolyn J. Hovde

    2003-01-01

    Enrichment and direct (nonenrichment) rectoanal mucosal swab (RAMS) culture techniques were developed and compared to traditional fecal culture for the detection of Escherichia coli O157:H7 in experimentally infected and naturally infected cattle. Holstein steers (n = 16) orally dosed with E. coli O157:H7 were sampled after bacterial colonization starting 15 days postinoculation. Enrichment RAMS cultures (70.31% positive) were more sensitive than enrichment fecal cultures with 10 g of feces (...

  19. Isotopomeric characterization of nitrous oxide produced by reaction of enzymes extracted from nitrifying and denitrifying bacteria

    Directory of Open Access Journals (Sweden)

    T. Yamazaki

    2013-10-01

    Full Text Available Nitrous oxide (N2O is a potent greenhouse gas and produced in denitrification and nitrification in environmental nitrogen cycle by various microorganism. Site preference (SP of 15N in N2O, which is defined as the difference in the natural abundance of isotopomers 14N15NO and 15N14NO relative to 14N14NO, has been reported to be a useful tool to quantitatively distinguish N2O production pathway. To determine representative SP value for each microbial process, we firstly measured SP of N2O produced in the enzyme reaction of hydroxylamine oxidoreductase (HAO purified from two species of ammonia oxidizing bacteria (AOB, Nitrosomonas europaea and Nitrosococcus oceani, and that of nitric oxide reductase (NOR from Paracoccus denitrificans, respectively. The SP value for NOR reaction (?5.9 ± 2.1‰ showed nearly the same value as that reported for N2O produced by P. denitrificans in pure culture. In contrast, SP value for HAO reaction (36.3 ± 2.3‰ was a little higher than the values reported for N2O produced by AOB in aerobic pure culture. Using the SP values obtained by HAO and NOR reactions, we calculated relative contribution of the nitrite (NO2– reduction (which is followed by NO reduction to N2O production by N. oceani incubated under different O2 availability. Our calculations revealed that previous in vivo studies might have underestimated the SP value for NH2OH oxidation pathway possibly due to a small contribution of NO2– reduction pathway. Further evaluation of isotopomer signatures of N2O using common enzymes of other processes related to N2O would improve the isotopomer analysis of N2O in various environments.

  20. Isotopomeric characterization of nitrous oxide produced by reaction of enzymes extracted from nitrifying and denitrifying bacteria

    Science.gov (United States)

    Yamazaki, T.; Hozuki, T.; Arai, K.; Toyoda, S.; Koba, K.; Fujiwara, T.; Yoshida, N.

    2014-05-01

    Nitrous oxide (N2O) is a potent greenhouse gas and produced in denitrification and nitrification by various microorganisms. Site preference (SP) of 15N in N2O, which is defined as the difference in the natural abundance of isotopomers 14N15NO and 15N14NO relative to 14N14NO, has been reported to be a useful tool to quantitatively distinguish N2O production pathways. To determine representative SP values for each microbial process, we firstly measured SP of N2O produced in the enzyme reaction of hydroxylamine oxidoreductase (HAO) purified from two species of ammonia oxidizing bacteria (AOB), Nitrosomonas europaea and Nitrosococcus oceani, and that of nitric oxide reductase (NOR) from Paracoccus denitrificans. The SP value for NOR reaction (-5.9 ± 2.1‰) showed nearly the same value as that reported for N2O produced by P. denitrificans in pure culture. In contrast, SP value for HAO reaction (36.3 ± 2.3‰) was a little higher than the values reported for N2O produced by AOB in aerobic pure culture. Using the SP values obtained by HAO and NOR reactions, we calculated relative contribution of the nitrite (NO2-) reduction (which is followed by NO reduction) to N2O production by N. oceani incubated under different O2 availability. Our calculations revealed that previous in vivo studies might have underestimated the SP value for the NH2OH oxidation pathway possibly due to a small contribution of NO2- reduction pathway. Further evaluation of isotopomer signatures of N2O using common enzymes of other processes related to N2O would improve the isotopomer analysis of N2O in various environments.

  1. Uranium enrichment: an evolving market

    International Nuclear Information System (INIS)

    With over half of the world uranium enrichment market uncommitted to any supplier early in the next century, competition is certain to be fierce. In the meantime the outlood remains unclear, with the market dominated by a number of developments -privatisation of the United States Enrichment Corp (USEC), increasing availability of Russian and US military inventories, the deployment of advanced technology and the closure of nuclear power plants due to deregulation. (author)

  2. Uranium enrichment by displacement chromatography

    International Nuclear Information System (INIS)

    Natural Uranium contains 0.72% of fissile isotope 235U. Need for 235U enriched uranium for light water moderated reactors and other uses are well known. Uranium enrichment is a highly complex and tedious process owing to extremely small separation factor. Several processes have been tried; however, gaseous diffusion and centrifugation techniques based on mass dependent isotope effect are being exploited for producing enriched uranium. In the recent past, Isotope fractionation based on mass independent isotope effect such as LASER technique, ion exchange displacement chromatography etc. have drawn the attention of separation scientist and efforts are being made for development and industrial deployment of these technologies. Indian Nuclear Power Programme is based on use of natural uranium (PHWRs) and slightly enriched uranium (BWRs, PWRs) with emphasis on use of vast resources of thorium. Spent fuel from PHWRs, which is depleted in 235U (0.2 to 0.3%), appears to be a promising source of slightly enriched uranium (1 to 3% 235U). Harnessing this source for 235U enrichment would augment fuel supply for PHWR and light water reactors. Ion exchange displacement chromatography is a proliferation resistant novel technique for 235U enrichment. It is based on nuclear field shift - an isotope shift in orbital electrons resulting from the isotopic difference in nuclear size and shape. Due to this effect lighter isotope (235U) exhibits a stronger tendency for a higher valence i.e. UO22+ as compared to heavier isotope (238U). Preliminary laboratory study is being carried out at HWP, Manuguru for exploring feasibility of using ion exchange displacement chromatography for enriching 235U using 4-vinyl pyridine based anion exchange resin

  3. Carbon availability and the distribution of denitrifying organisms influence N2O production in the hyporheic zone

    Science.gov (United States)

    Farrell, T. B.; Quick, A. M.; Reeder, W. J.; Tonina, D.; Benner, S. G.; Feris, K. P.

    2013-12-01

    It has been estimated that 10% of greenhouse gas N2O emissions take place within river networks, with the majority of these processes occurring in the hyporheic zone (HZ). These emissions are the result of microbially-mediated nitrogen transformations (i.e. nitrification and denitrification) and yet the role of microbial distribution and function in this complex system is not well understood. We hypothesized that the concentration and availability of organic carbon influences the production of redox gradients, DIN (via mineralization, nitrification, and loss of DIN via denitrification), and ultimately N2O production in the HZ by controlling the distribution and activity of denitrifying microbial communities. Further, we hypothesized that by linking the distribution of denitrifying microbial communities and their associated functional genes (i.e. the relative abundance of N2O vs. N2 producing genetic elements) to flow dynamics and biogeochemical processes, we can begin to better understand what controls N2O production in hyporheic networks. To address these hypotheses we performed a series of column experiments designed to determine the influence of carbon concentration on redox gradient development and N2O flux along a one-dimensional flow path. Intact sediment cores were amended with 0.01%, 0.05%, 0.15%, and 0.5% dry mass riparian vegetation (>90% Populus sp.) to serve as an endogenous particulate organic matter (POM) source. During quasi-steady state conditions dissolved oxygen (DO), NH4+, NO3-, and N2O levels were measured. As predicted, a positive relationship between the level of POM amendment and development of a gradient of oxic and anoxic conditions was observed. There was negligible N2O production within columns inoculated with 0.01% and 0.05% DOC likely because these POC treatments were too low to create anoxic conditions necessary to stimulate denitrification. Maximum N2O flux was observed with the 0.15% POC treatment. Both oxic and anoxic conditions were present in this treatment; conditions suitable for both nitrification and denitrification. However, N2O production was only observed where DO was below detection indicating denitrification as the source of N2O rather than nitrification. Minimal N2O flux was observed in the 0.5% POC treatment. This column was mostly anoxic, likely not supporting nitrification, and thereby limiting denitrification potential. During denitrification, expression of nitrous oxide reductase can enzymatically mediate the reduction of N2O to N2 and is encoded for by the nosZ gene. On-going work includes quantifying the distribution of the nosZ gene within each treatment to determine if the relative abundance of this genetic element correlates with N2O production or if production is primarily controlled by carbon availability and redox conditions.

  4. Real-time PCR assay for the simultaneous quantification of nitrifying and denitrifying bacteria in activated sludge

    Energy Technology Data Exchange (ETDEWEB)

    Geets, J.; Cooman, M. de; Wittebolle, L.; Verstraete, W.; Boon, N. [Ghent Univ. (BE). Lab. of Microbial Ecology and Technology (LabMET); Heylen, K.; Vanparys, B.; Vos, P. de [Ghent Univ. (Belgium). Dept. of Biochemistry, Physiology and Microbiology

    2007-05-15

    In order to improve wastewater treatment processes, a need exists for tools that rapidly give detailed insight into the community structure of activated sludge, supplementary to chemical and physical data. In this study, the advantages of microarrays and quantitative polymerase chin reaction (PCR) methods were combined into a real-time PCR assay that allows the simultaneous quantification of phylogenetic and functional genes involved in nitrification and denitrification processes. Simultaneous quantification was possible along a 5-log dynamic range and with high linear correlation (R{sup 2}>0.98). The specificity of the assay was confirmed by cloning and sequencing analyses of PCR amplicons obtained from activated sludge. The real-time assay was validated on mixed liquid samples of different treatment plants, which varied in nitrogen removal rate. The abundance of ammonia oxidizers was in the order of magnitude of 10{sup 6} down to 10{sup 4} ml{sup -1}, whereas nitrite oxidizers were less abundant (10{sup 3}-10{sup 1} order of magnitude). The results were in correspondence with the nitrite oxidation rate in the sludge types. As for the nirS, nirK, and nosZ gene copy numbers, their abundance was generally in the order of magnitude of 10{sup 8}-10{sup 5}. When sludge samples were subjected to lab-scale perturbations, a decrease in nitrification rate was reflected within 18 h in the copy numbers of nitrifier genes (decrease with 1 to 5 log units), whereas denitrification genes remained rather unaffected. These results demonstrate that the method is a fast and accurate tool for the analysis of the (de)nitrifying community structure and size in both natural and engineered environmental samples. (orig.)

  5. Evaluation of droplet digital PCR for characterizing plasmid reference material used for quantifying ammonia oxidizers and denitrifiers.

    Science.gov (United States)

    Dong, Lianhua; Meng, Ying; Wang, Jing; Liu, Yingying

    2014-02-01

    DNA reference materials of certified value have a critical function in many analytical processes of DNA measurement. Quantification of amoA genes in ammonia oxidizing bacteria (AOB) and archaea (AOA), and of nirS and nosZ genes in the denitrifiers is very important for determining their distribution and abundance in the natural environment. A plasmid reference material containing nirS, nosZ, amoA-AOB, and amoA-AOA is developed to provide a DNA standard with copy number concentration for ensuring comparability and reliability of quantification of these genes. Droplet digital PCR (ddPCR) was evaluated for characterization of the plasmid reference material. The result revealed that restriction endonuclease digestion of plasmids can improve amplification efficiency and minimize the measurement bias of ddPCR. Compared with the conformation of the plasmid, the size of the DNA fragment containing the target sequence and the location of the restriction site relative to the target sequence are not significant factors affecting plasmid quantification by ddPCR. Liquid chromatography-isotope dilution mass spectrometry (LC-IDMS) was used to provide independent data for quantifying the plasmid reference material. The copy number concentration of the digested plasmid determined by ddPCR agreed well with that determined by LC-IDMS, improving both the accuracy and reliability of the plasmid reference material. The reference value, with its expanded uncertainty (k?=?2), of the plasmid reference material was determined to be (5.19?±?0.41)?×?10(9) copies ?L(-1) by averaging the results of two independent measurements. Consideration of the factors revealed in this study can improve the reliability and accuracy of ddPCR; thus, this method has the potential to accurately quantify DNA reference materials. PMID:24493332

  6. Effect of land use on the density of nitrifying and denitrifying bacteria in the Colombian Coffee Region

    Directory of Open Access Journals (Sweden)

    Vallejo Quintero Victoria Eugenia

    2011-12-01

    Full Text Available

    Soil microbial communities involved in the cycling of nitrogen (N are essential to maintaining and improving soil fertility, productivity and functionality of natural and agricultural ecosystems. However, some compounds generated during the metabolic processes performed by nitrifying (NB and denitrifying (DB bacteria are associated with the production of greenhouse gases, groundwater pollution and acidification. Therefore, the study of these bacteria is essential for economic and environmental sustainability. This study evaluated the effect of different land uses in two river basins (La Vieja and Otun on NB and DB densities. Two sampling events (SE were conducted by selecting the most representative land uses. Physicochemical (T °, pH, moisture and nitrate and microbiological properties (NB and DB densities were evaluated. In both SEs, significantly higher densities of NB and DB were observed in the land uses: pasture, guadua (DB only and unshaded coffee (La Vieja and onion (Otun. These land uses, excluding guadua, are dependent on nitrogen fertilizers, which together with the activities of grazing livestock on pastures may lead to greater availability of substrates for the NB. The use of agricultural machinery and overgrazing in pasture and onion uses generate compacted soil and other physical disturbances, encouraging the growth of DB. Forests had the lowest densities of NB and DB possibly due to a reduced availability of N and the releasing of allelopathic compounds from certain plants. Finally, the densities of ammonium-oxidizing bacteria had the greatest differences between the land uses evaluated, demonstrating its high sensitivity to agricultural management practices and livestock. We suggest that changes in the abundance of this community could serve as a relevant and cost-effective bioindicator for soil monitoring.

  7. Asymmetric reduction of ketones and β-keto esters by (S)-1-phenylethanol dehydrogenase from denitrifying bacterium Aromatoleum aromaticum.

    Science.gov (United States)

    Dudzik, A; Snoch, W; Borowiecki, P; Opalinska-Piskorz, J; Witko, M; Heider, J; Szaleniec, M

    2015-06-01

    Enzyme-catalyzed enantioselective reductions of ketones and keto esters have become popular for the production of homochiral building blocks which are valuable synthons for the preparation of biologically active compounds at industrial scale. Among many kinds of biocatalysts, dehydrogenases/reductases from various microorganisms have been used to prepare optically pure enantiomers from carbonyl compounds. (S)-1-phenylethanol dehydrogenase (PEDH) was found in the denitrifying bacterium Aromatoleum aromaticum (strain EbN1) and belongs to the short-chain dehydrogenase/reductase family. It catalyzes the stereospecific oxidation of (S)-1-phenylethanol to acetophenone during anaerobic ethylbenzene mineralization, but also the reverse reaction, i.e., NADH-dependent enantioselective reduction of acetophenone to (S)-1-phenylethanol. In this work, we present the application of PEDH for asymmetric reduction of 42 prochiral ketones and 11 β-keto esters to enantiopure secondary alcohols. The high enantioselectivity of the reaction is explained by docking experiments and analysis of the interaction and binding energies of the theoretical enzyme-substrate complexes leading to the respective (S)- or (R)-alcohols. The conversions were carried out in a batch reactor using Escherichia coli cells with heterologously produced PEDH as whole-cell catalysts and isopropanol as reaction solvent and cosubstrate for NADH recovery. Ketones were converted to the respective secondary alcohols with excellent enantiomeric excesses and high productivities. Moreover, the progress of product formation was studied for nine para-substituted acetophenone derivatives and described by neural network models, which allow to predict reactor behavior and provides insight on enzyme reactivity. Finally, equilibrium constants for conversion of these substrates were derived from the progress curves of the reactions. The obtained values matched very well with theoretical predictions. PMID:25549618

  8. Comparison of enrichment measurement techniques for gas centrifuge enrichment plants

    International Nuclear Information System (INIS)

    A comparison of enrichment techniques has been carried out using a small bank of gas centrifuge enrichment units to simulate conditions in a commercial plant. The detectors compared included an in-line version of the gas phase enrichment monitor and a prototype Go-NoGo monitor. In these comparisons it was found that the gas phase enrichment monitor had an ultimate precision of about 0.5% for all measurements of enrichment between natural and 20%. The Go-NoGo instrument developed in the present programme was based on previous studies, and took advantage of the experience gained in other support programmes. Two different methods of correcting for wall deposits were investigated. On the basis of these studies a versatile Go-NoGo instrument has been designed for usage on pipes varying in diameter from 30 to 120 mm. Further development of this instrument will be carried out using a UF6 test loop facility which is currently under construction. (author)

  9. Removal of NO3--N from polluted groundwater in decommissioned mining area in an in-situ leach uranium mine by denitrifying bacteria bioreactor

    International Nuclear Information System (INIS)

    The pollution of groundwater by NO3- in the decommissioned mining area in an in-situ leach uranium mine is being paid more and more attention. The denitrifying bacteria by domesticating the sludge taken from the decommissioned mining area in an in-situ leach uranium mine in North West of China were obtained. An up-flow fixed-bed denitrifying bacteria bioreactor was designed. The effects of pH, the ratio of carbon to nitrogen and HRT on the removal of NO3--N from the polluted groundwater in the decommissioned mining area in the in-situ leach uranium mine by the denitrifying bacteria bioreactor were investigated. The results show that when pH, the concentration of NO3--N and HRT are set to 6.50, 1000 mg/L and 2.3 h, respectively, the removal of the NO3--N amounts to 97%, the NO3--N degradation rate is 388 mg/(h · L) and the capacity of the bioreactor is 0. 35 m3/(h · m3). When pH , the concentration of NO3--N and HRT are set to 6.50, 550 mg/L and 1.4 h, respectively, the removal of the NO3--N amounts to 96% and the capacity of the bioreactor is 0.62 m3/(h · m3). The bioreactor should work on the operation conditions that pH is 5.00-8.00 and the ratio of carbon to nitrogen is 0.6-0.8. (authors)

  10. Draft genome sequence of the denitrifying strain Kiloniella sp. P1-1 isolated from the gut microflora of Pacific white shrimp, Litopenaeus vannamei.

    Science.gov (United States)

    Wang, Liping; Li, Xiaoyi; Shao, Zongze

    2015-12-01

    A denitrifying bacterium, Kiloniella sp. P1-1, was isolated from the intestinal tract contents of Pacific white shrimp (Litopenaeus vannamei) from the Taiwan Strait, China. Here we report the draft genome sequence of Kiloniella sp. P1-1, which comprised 4,312,146 bp in 85 contigs with a G+C content of 46.09%. Related genes involved in the denitrification process could be identified in this genome. The genome sequence of Kiloniella sp. P1-1 may provide insights into the mechanism of denitrification. PMID:26303669

  11. Why is Brazil enriching uranium?

    International Nuclear Information System (INIS)

    In Brazil construction began in 1971 on Angra 1, a 626 MW Westinghouse pressurized water reactor (PWR). It was completed in 1984. Later, Angra 2 (a Kraftwerk Union PWR) achieved commercial operation in 2000. Brazil is considering the construction of seven nuclear power plants over the next 15 years. In preparation for this nuclear industry expansion, Brazil is building a uranium enrichment facility to provide nuclear fuel for Angra 1 and 2 starting in 2010 at Resende in the state of Rio de Janeiro, and collated with nuclear fuel fabrication facilities. This paper investigates whether the Resende Enrichment Facility will be able to provide uranium enrichment services at a cost lower than the international market price. We find that while Brazil is unlikely to be internationally competitive in the enrichment market, the Resende Enrichment Facility completes the front end of Brazil's nuclear fuel cycle. This assures uninterrupted nuclear fuel to its currently operating light water reactors, while providing the option of expanding capacity, lowering cost, and competing in the international nuclear fuel market after 2020

  12. Why is Brazil enriching uranium?

    Energy Technology Data Exchange (ETDEWEB)

    Cabrera-Palmer, Belkis [Center for International Security and Cooperation (CISAC), Stanford University, Stanford, CA 94305-6165 (United States); Rothwell, Geoffrey [Department of Economics, Stanford University, Stanford, CA 94305-6072 (United States)

    2008-07-15

    In Brazil construction began in 1971 on Angra 1, a 626 MW Westinghouse pressurized water reactor (PWR). It was completed in 1984. Later, Angra 2 (a Kraftwerk Union PWR) achieved commercial operation in 2000. Brazil is considering the construction of seven nuclear power plants over the next 15 years. In preparation for this nuclear industry expansion, Brazil is building a uranium enrichment facility to provide nuclear fuel for Angra 1 and 2 starting in 2010 at Resende in the state of Rio de Janeiro, and collated with nuclear fuel fabrication facilities. This paper investigates whether the Resende Enrichment Facility will be able to provide uranium enrichment services at a cost lower than the international market price. We find that while Brazil is unlikely to be internationally competitive in the enrichment market, the Resende Enrichment Facility completes the front end of Brazil's nuclear fuel cycle. This assures uninterrupted nuclear fuel to its currently operating light water reactors, while providing the option of expanding capacity, lowering cost, and competing in the international nuclear fuel market after 2020. (author)

  13. Uranium enrichment: technology, economics, capacity

    International Nuclear Information System (INIS)

    Large-scale enrichment of uranium has now been carried out for 40 years. While the gaseous diffusion process was the original choice of several countries and continues today to provide the major component of the world production of separative work, the last two decades have witnessed the development of a number of alternative processes for enrichment. These processes, which are being studied and deployed around the world, offer a wide range of technical and economic characteristics which will be useful in assuring adequate capacity to meet projected reactor fuel market needs through the rest of this century at competitive prices. With present uncertainties in future enriched uranium needs, it is apparent that flexibility in the deployment and operation of any enrichment process will be one of the prime considerations for the future. More economical production of separative work not only can have a beneficial impact on reactor fuel costs, but also tends to conserve natural uranium resources. This paper reviews the world scene in the enrichment component of the fuel cycle, including existing or planned commercial-scale facilities and announced R and D efforts on various processes

  14. Observation of high seasonal variation in community structure of denitrifying bacteria in arable soil receiving artificial fertilizer and cattle manure by determining T-RFLP of nir gene fragments

    DEFF Research Database (Denmark)

    Priemé, Anders; Wolsing, Martin

    2004-01-01

    Temporal and spatial variation of communities of soil denitrifying bacteria at sites receiving mineral fertilizer (60 and 120 kg N ha-1 year-1) and cattle manure (75 and 150 kg N ha-1 year-1) were explored using terminal restriction fragment length polymorphism (T-RFLP) analyses of PCR amplified...... significant seasonal shift in the community structure of nirK-containing bacteria. Also, sites treated with mineral fertilizer or cattle manure showed different communities of nirK-containing denitrifying bacteria, since the T-RFLP patterns of soils treated with these fertilizers were significantly different...

  15. Enrichment of light hydrocarbon mixture

    Energy Technology Data Exchange (ETDEWEB)

    Yang; Dali (Los Alamos, NM); Devlin, David (Santa Fe, NM); Barbero, Robert S. (Santa Cruz, NM); Carrera, Martin E. (Naperville, IL); Colling, Craig W. (Warrenville, IL)

    2010-08-10

    Light hydrocarbon enrichment is accomplished using a vertically oriented distillation column having a plurality of vertically oriented, nonselective micro/mesoporous hollow fibers. Vapor having, for example, both propylene and propane is sent upward through the distillation column in between the hollow fibers. Vapor exits neat the top of the column and is condensed to form a liquid phase that is directed back downward through the lumen of the hollow fibers. As vapor continues to ascend and liquid continues to countercurrently descend, the liquid at the bottom of the column becomes enriched in a higher boiling point, light hydrocarbon (propane, for example) and the vapor at the top becomes enriched in a lower boiling point light hydrocarbon (propylene, for example). The hollow fiber becomes wetted with liquid during the process.

  16. Enrichment of light hydrocarbon mixture

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Dali (Los Alamos, NM); Devlin, David (Santa Fe, NM); Barbero, Robert S. (Santa Cruz, NM); Carrera, Martin E. (Naperville, IL); Colling, Craig W. (Warrenville, IL)

    2011-11-29

    Light hydrocarbon enrichment is accomplished using a vertically oriented distillation column having a plurality of vertically oriented, nonselective micro/mesoporous hollow fibers. Vapor having, for example, both propylene and propane is sent upward through the distillation column in between the hollow fibers. Vapor exits neat the top of the column and is condensed to form a liquid phase that is directed back downward through the lumen of the hollow fibers. As vapor continues to ascend and liquid continues to countercurrently descend, the liquid at the bottom of the column becomes enriched in a higher boiling point, light hydrocarbon (propane, for example) and the vapor at the top becomes enriched in a lower boiling point light hydrocarbon (propylene, for example). The hollow fiber becomes wetted with liquid during the process.

  17. A Systematic Approach to Marital Enrichment.

    Science.gov (United States)

    Dinkmeyer, Don; Carlson, Jon

    1986-01-01

    Presents a systematic approach to enriching marital relationships. The history and current status of marital enrichment is reviewed. An Adlerian approach to marital enrichment is described. Applications of the program in enrichment groups, marriage therapy and couple groups are included. (Author)

  18. Advances in uranium enrichment processes

    International Nuclear Information System (INIS)

    Advances in gas centrifuges and development of the atomic vapour laser isotope separation process promise substantial reductions in the cost of enriched uranium. The resulting reduction in LWR fuel costs could seriously erode the economic advantage of CANDU, and in combination with LWR design improvement, shortened construction times and increased operational reliability could allow the LWR to overtake CANDU. CANDU's traditional advantages of neutron economy and high reliability may no longer be sufficient - this is the challenge. The responses include: combining neutron economy and dollar economy by optimizing CANDU for slightly enriched uranium fuel; developing cost-reducing improvements in design, manufacture and construction; and reducing the cost of heavy water. Technology is a renewable resource which must be continually applied to a product for it to remain competitive in the decades to come. Such innovation is a prerequisite to Canada increasing her share of the international market for nuclear power stations. The higher burn-up achievable with enriched fuel in CANDU can reduce the fuel cycle costs by 20 to 40 percent for a likely range of costs for yellowcake and separative work. Alternatively, some of the benefits of a higher fissile content can take the form of a cheaper reactor core containing fewer fuel channels and less heavy water, and needing only a single fuelling machine. An opportunity that is linked to this need to introduce an enriched uranium fuel cycle into CANDU is to build an enrichment business in Canada. This could offer greater value added to our uranium exports, security of supply for enriched CANDUs, technological growth in Canada and new employment opportunities. AECL has a study in progress to define this opportunity

  19. Advances in uranium enrichment processes

    International Nuclear Information System (INIS)

    Advances in gas centrifuges and development of the atomic vapour laser isotope separation process promise substantial reductions in the cost of enriched uranium. The resulting reduction in LWR fuel costs could seriously erode the economic advantage of CANDU, and in combination with LWR design improvements, shortened construction times and increased operational reliability could allow the LWR to overtake CANDU. CANDU's traditional advantages of neutron economy and high reliability may no longer be sufficient - this is the challenge. The responses include: combining neutron economy and dollar economy by optimizing CANDU for slightly enriched uranium fuel; developing cost-reducing improvements in design, manufacture and construction; and reducing the cost of heavy water. Technology is a renewable resource which must be continually applied to a product for it to remain competitive in the decades to come. Such innovation is a prerequisite to Canada increasing her share of the international market for nuclear power stations. The higher burn-up achievable with enriched fuel in CANDU can reduce the fuel cycle costs by 20 to 40 percent for a likely range of costs for yellowcake and separative work. Alternatively, some of the benefits of a higher fissile content can take the form of a cheaper reactor core containing fewer fuel channels and less heavy water, and needing only a single fuelling machine. An opportunity that is linked to this need to introduce an enriched uranium fuel cycle into CANDU is to build an enrichment business in Canada. This could offer greater value added to our uranium exports, security of supply for enriched CANDUs, technological growth in Canada and new employment opportunities. AECL has a study in progress to define this opportunity

  20. Morita theory in enriched context

    OpenAIRE

    Segrt Ratkovic, Kruna

    2012-01-01

    We develop a homotopy theoretical version of classical Morita theory using the notion of a strong monad. It was Anders Kock who proved that a monad T in a monoidal category E is strong if and only if T is enriched in E. We prove that this correspondence between strength and enrichment follows from a 2-isomorphism of 2-categories. Under certain conditions on T, we prove that the category of T-algebras is Quillen equivalent to the category of modules over the endomorphism monoid of the T-algebr...

  1. Mixing Intensity Effects of Attached Growth on Enriched Anammox Cultures

    Directory of Open Access Journals (Sweden)

    Pongsak Noophan

    2015-01-01

    Full Text Available Anaerobic ammonium oxidation (anammox is a promising new technology for the treatment of wastewater with high ammonium and low carbon concentrations. Earlier work suggests that optimal processing would be realized within a sequencing batch reactor (SBR. However, the relatively slow growth of anammox bacteria inhibits the rates of nitrogen removal and biomass yielding. Improved anammox performance has been demonstrated when the bacteria are in granular form or attached to a growth medium. Little has been reported concerning the effect of mixing rate on nitrogen (N removal with attached anammox bacteria. This work subjected anammox bacteria attached to polystyrene sponge in SBR to various intensities of impeller mixing and studied the effect on NH4+ and NO2- removal. Nitrogen processing was virtually the same with velocity gradient values between 13.5 and 222 s-1. More vigorous mixing at 407 and 666 s-1 values significantly inhibited N removal, likely due to detachment of bacteria from the growth medium. Following the poor N removal at the two higher mixing intensities, agitation was reduced to 24.8 s-1 velocity gradient value. Recovery of N removal rates required 2-3 weeks, the slow time attributed to slow reattachment to the growth medium. Denaturing gradient gel electrophoresis (DGGE analysis identified the prominent anammox species in the experimental study as Candidatus Brocadia anammoxidans and Candidatus Kuenenia stuttgartiensis.

  2. Characterization of an anaerobic thermophilic glycerol-degrading enrichment culture

    OpenAIRE

    Cavaleiro, A.J.; Sousa, D. Z.; Alves, M. M.; A. J. M. Stams

    2015-01-01

    Background: The glycerol market was totally changed by the biodiesel industry, which resulted in the production of an excess of this compound as an industrial by-product. As a consequence, the price of glycerol dropped and a huge interest in alternatives for its valorisation emerged since then. In the field of Biotechnology research, glycerol is an attractive compound for the microbial production of chemical building blocks. Objectives: The aim of this work was to investigate thermophilic...

  3. Uranium enrichment in the United States

    International Nuclear Information System (INIS)

    History, improvement programs, status of electrical power availability, demands for uranium enrichment, operating plan for the U. S. enriching facilities, working inventory of enriched uranium, possible factors affecting deviations in the operating plan, status of gaseous diffusion technology, status of U. S. gas centrifuge advances, transfer of enrichment technology, gaseous diffusion--gas centrifuge comparison, new enrichment capacity, U. S. separative work pricing, and investment in nuclear energy are discussed. (LK)

  4. Bioaugmentation of nitrate-dependent anaerobic ferrous oxidation by heterotrophic denitrifying sludge addition: A promising way for promotion of chemoautotrophic denitrification.

    Science.gov (United States)

    Wang, Ru; Zheng, Ping; Zhang, Meng; Zhao, He-Ping; Ji, Jun-Yuan; Zhou, Xiao-Xin; Li, Wei

    2015-12-01

    Nitrate-dependent anaerobic ferrous oxidation (NAFO) is a new and valuable bio-process for the treatment of wastewaters with low C/N ratio, and the NAFO process is in state of the art. The heterotrophic denitrifying sludge (HDS), possessing NAFO activity, was used as bioaugmentation to enhance NAFO efficiency. At a dosage of 6% (V/V), the removal of nitrate and ferrous was 2.4 times and 2.3 times of as primary, and the volumetric removal rate (VRR) of nitrate and ferrous was 2.4 times and 2.2 times of as primary. Tracing experiments of HDS indicated that the bioaugmentation on NAFO reactor was resulted from the NAFO activity by HDS itself. The predominant bacteria in HDS were identified as Thauera (52.5%) and Hyphomicrobium (20.0%) which were typical denitrifying bacteria and had potential ability to oxidize ferrous. In conclusion, HDS could serve as bioaugmentation or a new seeding sludge for operating high-efficiency NAFO reactors. PMID:26348287

  5. Hydrogenotrophic denitrification process efficiency and the number of denitrifying bacteria (MPN) in the sequencing batch biofilm reactor (SBBR) with platinum and carbon anodes.

    Science.gov (United States)

    KÅ‚odowska, Izabella; Rodziewicz, Joanna; Janczukowicz, Wojciech; Gotkowska-PÅ‚achta, Anna; Cydzik-Kwiatkowska, Agnieszka

    2016-04-15

    This work reports on the effect of electric current density and anode material (platinum, carbon) on the concentration of oxidized and mineral forms of nitrogen, on physical parameters (pH, redox potential, electrical conductivity) and the number of denitrifying bacteria in the biofilm (MPN). Experiments were conducted under anaerobic conditions without and with the flow of electric current (with density of 79 mA·m(-2) and 132 mA·m(-2)). Results obtained in the study enabled concluding that increasing density of electric current caused a decreasing concentration of nitrate in the reactor with platinum anode (R1) and carbon anode (R2). Its concentration depended on anode material. The highest hydrogenotrophic denitrification efficiency was achieved in R2 in which the process was aided by inorganic carbon (CO2) that originated from carbon anode oxidation and the electrical conductivity of wastewater increased as a result of the presence of HCO3(-) and CO3(2-) ions. Strong oxidizing properties of the platinum anode (R1) prevented the accumulation of adverse forms of nitrogen, including nitrite and ammonia. The increase in electric current density affected also a lower number of denitrifying bacteria (MPN) in the biofilm in both reactors (R1 and R2). Metal oxides accumulated on the surface of the cathode had a toxic effect upon microorganisms and impaired the production of a hydrogen donor. PMID:26809836

  6. Two-step nitrification in a pure moving bed biofilm reactor-membrane bioreactor for wastewater treatment: nitrifying and denitrifying microbial populations and kinetic modeling.

    Science.gov (United States)

    Leyva-Díaz, J C; González-Martínez, A; Muñío, M M; Poyatos, J M

    2015-12-01

    The moving bed biofilm reactor-membrane bioreactor (MBBR-MBR) is a novel solution to conventional activated sludge processes and membrane bioreactors. In this study, a pure MBBR-MBR was studied. The pure MBBR-MBR mainly had attached biomass. The bioreactor operated with a hydraulic retention time (HRT) of 9.5 h. The kinetic parameters for heterotrophic and autotrophic biomasses, mainly nitrite-oxidizing bacteria (NOB), were evaluated. The analysis of the bacterial community structure of the ammonium-oxidizing bacteria (AOB), NOB, and denitrifying bacteria (DeNB) from the pure MBBR-MBR was carried out by means of pyrosequencing to detect and quantify the contribution of the nitrifying and denitrifying bacteria in the total bacterial community. The relative abundance of AOB, NOB, and DeNB were 5, 1, and 3 %, respectively, in the mixed liquor suspended solids (MLSS), and these percentages were 18, 5, and 2 %, respectively, in the biofilm density (BD) attached to carriers. The pure MBBR-MBR had a high efficiency of total nitrogen (TN) removal of 71.81 ± 16.04 %, which could reside in the different bacterial assemblages in the fixed biofilm on the carriers. In this regard, the kinetic parameters for autotrophic biomass had values of Y A  = 2.3465 mg O2 mg N(-1), ? m, A = 0.7169 h(-1), and K NH = 2.0748 mg N L(-1). PMID:26264139

  7. Relationship between N2O Fluxes from an Almond Soil and Denitrifying Bacterial Populations Estimated by Quantitative PCR

    Science.gov (United States)

    Matiasek, M.; Suddick, E. C.; Smart, D. R.; Scow, K. M.

    2008-12-01

    Cultivated soils emit substantial quantities of nitrous oxide (N2O), a greenhouse gas with almost 300 times the radiative forcing potential of CO2. Agriculture-related activities generate from 6 to 35 Tg N2O-N per year, or about 60 to 70% of global production. The microbial processes of nitrification, denitrification and nitrifier denitrification are major biogenic sources of N2O to the atmosphere from soils. Denitrification is considered the major source of N2O especially when soils are wet. The microbial N transformations that produce N2O depend primarily on nitrogen (N) fertilizer, with water content, available carbon and soil temperature being secondary controllers. Despite the fact that microbial processes are responsible for N2O emissions, very little is known about the numbers or types of populations involved. The objective of this study was to relate changes in denitrifying population densities, using quantitative PCR (qPCR) of functional genes, to N2O emissions in a fertilized almond orchard. Quantitative PCR targeted three specific genes involved in denitrification: nirS, nirK and nosZ. Copy numbers of the genes were related back to population densities and the portion of organisms likely to produce nitrous oxide. The study site, a 21.7 acre almond orchard fitted with micro-sprinklers, was fertigated (irrigated and fertilized simultaneously) with 50 lbs/acre sodium nitrate in late March 2008, then irrigated weekly. Immediately after the initial fertigation, fluxes of N2O and CO2, moisture content, inorganic N and denitrification gene copy numbers were measured 6 times over 24 days. Despite the fact that N2O emissions increased following fertigation, there was no consistent increase in any of the targeted genes. The genes nirK and nirS ranged from 0.4-1.4 × 107 and 0.4-1.4 × 108, whereas nosZ ranged from 2-8 × 106 copy numbers per g soil, respectively. Considerable variation, compounded by the small sample sizes used for DNA analysis, made it difficult to discern trends over time. High spatial variability was also observed with one of the field replicates have a substantially higher flux of N2O. This replicate also had the highest water filled pore space (WFPS) and water content, factors that likely favored denitrification. Water saturation of soil air space, optimal at >60% for denitrification to occur, was relatively low in the other field replicates. Thus, the low N2O flux measurements and gene copy numbers agreed in supporting the hypothesis denitrification was relatively low under the environmental conditions of these particular almond soils.

  8. Identification of the function of extracellular polymeric substances (EPS) in denitrifying phosphorus removal sludge in the presence of copper ion.

    Science.gov (United States)

    Wang, Yayi; Qin, Jian; Zhou, Shuai; Lin, Ximao; Ye, Liu; Song, Chengkang; Yan, Yuan

    2015-04-15

    Industrial wastewater containing heavy metals that enters municipal wastewater treatment plants inevitably has a toxic impact on biological treatment processes. In this study, the impact of Cu(II) (0, 1.5, 2, 2.5, 3 mg/L) on the performance of denitrifying phosphorus removal (DPR) and microbial community structures was investigated. Particularly, the dynamic change in the amount and composition of extracellular polymeric substances (EPS), and the role of EPS in P removal, were assessed using three-dimensional excitation-emission matrix fluorescence spectroscopy combined with parallel factor (PARAFAC) analysis. The results showed that, after long-term adjustment, the P removal efficiency was maintained at 95 ± 2.7% at Cu(II) addition up to 2.5 mg/L, but deteriorated when the Cu(II) addition was 3 mg/L. The EPS content, including proteins and humic substances, increased with increasing Cu(II) additions at concentrations ?2.5 mg/L. This property of EPS was beneficial for protecting phosphate-accumulating organisms (PAOs) against heavy metals, as both proteins and humic substances are strong ligands for Cu(II). Therefore, the PAOs abundance was still relatively high (67 ± 3%) when Cu(II) accumulation in sludge was up to 10 mg/g SS. PARAFAC confirmed that aromatic proteins could be transformed into soluble microbial byproduct-like material when microorganisms were subjected to Cu(II) stress, owing to their strong metal ion complexing capacity. The increase in the percentage of humic-like substances enhanced the detoxification function of the sludge EPS. EPS accounted for approximately 26-47% of P removed by adsorption when Cu(II) additions were between 0 and 2.5 mg/L. The EPS function, including binding toxic heavy metals and P storage, enhanced the operating stability of DPR systems. This study provides us with a better understanding of (1) the tolerance of DPR sludge to copper toxicity and (2) the function of sludge EPS in the presence of heavy metals in biological P removal systems. PMID:25697691

  9. Enriched Fell Bundles and Spaceoids

    CERN Document Server

    Bertozzini, Paolo; Lewkeeratiyutkul, Wicharn

    2011-01-01

    We propose a definition of involutive categorical bundle (Fell bundle) enriched in an involutive monoidal category and we argue that such a structure is a possible suitable environment for the formalization of different equivalent versions of spectral data for commutative C*-categories.

  10. Environmental Development Plan: uranium enrichment

    International Nuclear Information System (INIS)

    This Environmental Development Plan identifies and examines the environmental, health, safety, and socioeconomic concerns and corresponding requirements associated with the DOE research, development, demonstration, and operation of the Uranium Enrichment program, including the gaseous diffusion process, the centrifuge process, centrifuge rotor fabrication, and related research and development activities

  11. Enrichment reduction for research reactors

    International Nuclear Information System (INIS)

    The worldwide activities on enrichment reduction for research reactors are reviewed and the national and international programs are described. Especially the following points are discussed: Benchmark calculations, reactor safety, fuel element development, irradiation tests, post irradiation examinations, full core demonstrations, activities of the GKSS and economical questions. (orig.)

  12. Selective enrichment of a methanol-utilizing consortium using pulp & paper mill waste streams

    Energy Technology Data Exchange (ETDEWEB)

    Gregory R. Mockos; William A. Smith; Frank J. Loge; David N. Thompson

    2007-04-01

    Efficient utilization of carbon inputs is critical to the economic viability of the current forest products sector. Input carbon losses occur in various locations within a pulp mill, including losses as volatile organics and wastewater . Opportunities exist to capture this carbon in the form of value-added products such as biodegradable polymers. Waste activated sludge from a pulp mill wastewater facility was enriched for 80 days for a methanol-utilizing consortium with the goal of using this consortium to produce biopolymers from methanol-rich pulp mill waste streams. Five enrichment conditions were utilized: three high-methanol streams from the kraft mill foul condensate system, one methanol-amended stream from the mill wastewater plant, and one methanol-only enrichment. Enrichment reactors were operated aerobically in sequencing batch mode at neutral pH and 25°C with a hydraulic residence time and a solids retention time of four days. Non-enriched waste activated sludge did not consume methanol or reduce chemical oxygen demand. With enrichment, however, the chemical oxygen demand reduction over 24 hour feed/decant cycles ranged from 79 to 89 %, and methanol concentrations dropped below method detection limits. Neither the non-enriched waste activated sludge nor any of the enrichment cultures accumulated polyhydroxyalkanoates (PHAs) under conditions of nitrogen sufficiency. Similarly, the non-enriched waste activated sludge did not accumulate PHAs under nitrogen limited conditions. By contrast, enriched cultures accumulated PHAs to nearly 14% on a dry weight basis under nitrogen limited conditions. This indicates that selectively-enriched pulp mill waste activated sludge can serve as an inoculum for PHA production from methanol-rich pulp mill effluents.

  13. Community Structure Evolution and Enrichment of Glycogen-Accumulating Organisms Producing Polyhydroxyalkanoates from Fermented Molasses?

    OpenAIRE

    Pisco, Ana R.; Bengtsson, Simon; Werker, Alan; Maria A. M. Reis; Lemos, Paulo C.

    2009-01-01

    An open mixed culture was enriched with glycogen-accumulating organisms (GAOs) by using a sequencing batch reactor and treating an agroindustrial waste (sugar cane molasses) under cyclic anaerobic-aerobic conditions. Over a 1-year operating period, the culture exhibited a very stable GAO phenotype with an average polyhydroxyalkanoate (PHA) content of 17% total suspended solids. However, the GAO microbial community evolved over the course of operation to a culture exhibiting unusual characteri...

  14. Simulations of Cosmic Chemical Enrichment

    CERN Document Server

    Kobayashi, C; White, S D M; Kobayashi, Chiaki; Springel, Volker; White, Simon D. M.

    2006-01-01

    Using a new numerical model for cosmic chemical evolution, we study the influence of hypernova feedback on the star formation and metal enrichment history of the universe. For assumptions which produce plausible results in idealized collapse models of individual galaxies, our cosmological simulations of the standard Lambda-CDM cosmology show a peak of the cosmic star formation rate at z~4, with ~10% of the baryons turning into stars. We find that the majority of stars in present-day massive galaxies formed in much smaller galaxies at high redshifts, giving them a mean stellar age as old as 10 Gyr, despite their late assembly times. The hypernova feedback drives galactic outflows efficiently in low mass galaxies, and these winds eject heavy elements into the intergalactic medium. The ejected baryon fraction is larger for less massive galaxies, correlates well with stellar metallicity, and amounts to ~20% of all baryons in total. The resulting enrichment history is broadly consistent with the observed abundance...

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

    Science.gov (United States)

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

    2014-05-01

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

  16. Boron Enrichment in Martian Clay

    OpenAIRE

    Stephenson, James D.; Hallis, Lydia J.; Nagashima, Kazuhide; Freeland, Stephen J.

    2013-01-01

    We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest minera...

  17. Introducing Enriched Concrete Syntax Trees

    OpenAIRE

    Raki?, Gordana; Zoran BUDIMAC

    2013-01-01

    In our earlier research an area of consistent and systematic application of software metrics was explored. Strong dependency of applicability of software metrics on input programming language was recognized as one of the main weaknesses in this field. Introducing enriched Concrete Syntax Tree (eCST) for internal and intermediate representation of the source code resulted with step forward over this weakness. In this paper we explain innovation made by introducing eCST and pr...

  18. Enrichment techniques employed in phosphoproteomics.

    Czech Academy of Sciences Publication Activity Database

    Fíla, Jan; Honys, David

    2012-01-01

    Ro?. 43, ?. 3 (2012), s. 1025-1047. ISSN 0939-4451 R&D Projects: GA ?R(CZ) GAP501/11/1462; GA ?R GA522/09/0858; GA ?R GA525/09/0994; GA MŠk OC08011 Institutional research plan: CEZ:AV0Z50380511 Keywords : Phosphoproteomics * Enrichment * IMAC Subject RIV: ED - Physiology Impact factor: 3.914, year: 2012

  19. CNA Laboratory Enrichment By Virtualization

    OpenAIRE

    Adodo, Segun

    2011-01-01

    This study is related to networking and the aim is to enrich the laboratory work aspect of the networking study module as implemented by the school’s information technology department. The existing practice lab structures in the institution’s information technology degree programme rely more on Microsoft windows than other operating systems. As a result, experience in non-window operating systems is low in students. To increase the awareness of the Linux operating system among networking ...

  20. Microscale effects on denitrification: does the ability of denitrifying bacteria to reduce N2O depend on their position in the soil matrix?

    Science.gov (United States)

    Dörsch, Peter; Nadeem, Shahid; Almås, Åsgeir; Bakken, Lars R.

    2013-04-01

    Soil is a heterogeneous matrix with a variety of microhabitats which probably select for organisms with distinct functional traits. The composition and functioning of soil denitrifier communities (DC) has been studied intensely over the last decades, primarily because of their role in the emission of N2O from soil. The tacit assumption in such studies is that the soil microbial community is one "thing". In the present study, we challenge the concept of DC as a homogenous entity and suggest a stratification of denitrifier function based on the position within the soil matrix. We hypothesize that soil contains "inner" and "outer" habitats; the inner consisting of sites within crevices and cavities of the soil mineral material, structured organic materials and strong biofilms, the outer consisting of exposed surfaces and macropores within the soil matrix. We further believe that sequential dispersion/extraction by density gradient centrifugation (DGC) can be used to crudely separate the organisms residing in the two habitat types. We operationally define loosely attached cells (LAC) as those which are liberated from soil particles by moderate dispersion of soils. LAC were separated from the soil by DGC, and the pellets at the bottom of the gradients containing bacteria still attached to or embedded in soil material were then subjected to a stronger dispersion to release the more strongly attached cells (SAC) which were again separated from the soil by DGC. We hypothesized that SAC are cells situated deeper in biofilms or other protective structures within the soil matrix than LAC. We further hypothesized that the two habitats select for different characteristics regarding the regulation of denitrification. In short, SAC were expected to express N2O-reductase earlier than LAC, because SAC experience anoxia and lack of NOx more frequently than LAC. First results from incubations with LAC and SAC from different soils lend strong support to this hypothesis; in response to oxygen depletion, both denitrifying communities expressed similar apparent growth rates, both produced a mixture of NO, N2O and N2, but the relative amount of N2O produced was much higher for LAC than SAC. This reemphasizes the significance of soil structure, habitable pore space, predation and bacteria-mineral interactions as regulating factors for N2O emission in mineral soils and has implications for the understanding of selection pressures for sustained N2O-reductase activity in soil.

  1. Nitrite survival and nitrous oxide production of denitrifying phosphorus removal sludges in long-term nitrite/nitrate-fed sequencing batch reactors.

    Science.gov (United States)

    Wang, Yayi; Zhou, Shuai; Ye, Liu; Wang, Hong; Stephenson, Tom; Jiang, Xuxin

    2014-12-15

    Nitrite-based phosphorus (P) removal could be useful for innovative biological P removal systems where energy and carbon savings are a priority. However, using nitrite for denitrification may cause nitrous oxide (N2O) accumulation and emissions. A denitrifying nitrite-fed P removal system [Formula: see text] was successfully set up in a sequencing batch reactor (SBR) and was run for 210 days. The maximum pulse addition of nitrite to [Formula: see text] was 11 mg NO2(-)-N/L in the bulk, and a total of 34 mg NO2(-)-N/L of nitrite was added over three additions. Fluorescent in situ hybridization results indicated that the P-accumulating organisms (PAOs) abundance was 75 ± 1.1% in [Formula: see text] , approximately 13.6% higher than that in a parallel P removal SBR using nitrate [Formula: see text] . Type II Accumulibacter (PAOII) (unable to use nitrate as an electron acceptor) was the main PAOs species in [Formula: see text] , contributing 72% to total PAOs. Compared with [Formula: see text] , [Formula: see text] biomass had enhanced nitrite/free nitrous acid (FNA) endurance, as demonstrated by its higher nitrite denitrification and P uptake rates. N2O accumulated temporarily in [Formula: see text] after each pulse of nitrite. Peak N2O concentrations in the bulk for [Formula: see text] were generally 6-11 times higher than that in [Formula: see text] ; these accumulations were rapidly denitrified to nitrogen gases. N2O concentration increased rapidly in nitrate-cultivated biomass when 5 or 10 mg NO2(-)-N/L per pulse was added. Whereas, N2O accumulation did not occur in nitrite-cultivated biomass until up to 30 mg NO2(-)-N/L per pulse was added. Long-term acclimation to nitrite and pulse addition of nitrite in [Formula: see text] reduced the risk of nitrite accumulation, and mitigated N2O accumulation and emissions from denitrifying P removal by nitrite. PMID:25261626

  2. Uranium enrichment and public policy

    International Nuclear Information System (INIS)

    Alternative policies to the present government monopoly of the uranium enrichment process are discussed in this monograph. Alternative policies analyzed are continued government monopoly and operation by the Department of Energy, establishment of a government corporation, and complete relinquishing of government control with the private sector taking the risks of constructing additional capacity. The material is divided into 6 chapters. Chapter 1 describes the fuel cycle and the public policy issues involved. The enrichment process, current capacity, and the operation of the plants by the government are described in Chapter 2. Chapter 3 estimates future demand for electricity in the U.S. and forecasts the demand for nuclear power and for enrichment services. Chapter 4 describes the historical background, including the Nuclear Fuel Assurance Act, opposition to it, and its demise. The basic policy options the government faces with an analysis of the advantages and disadvantages of each are included in Chapter 5. The final chapter summarizes the findings and presents the conclusion that, from an economic efficiency viewpoint, selling the existing plants and turning the industry over to the private sector would be best. An appendix describes some of the issues involved in plutonium recycling

  3. Cascade device for enriching uranium

    International Nuclear Information System (INIS)

    Object: To separate and remove impure gas of light mass from a flow of UF6 gas and increase the UF6 gas in pressure to be fed into stages, thereby enhancing cascade effect. Structure: Raw gas supplied from a raw material supply pipe is introduced into a separator while mixed with waste gas fed from a first stage on the enriching side through a connection pipe and product gas fed from a first stage on the depletion side through another connection pipe. The separator has its function to separate light gas from heavy gas by the action of centrifugal force to increase pressure of the heavy gas. The thus separated light gas is discharged outside the system by means of a vacuum pump through a light gas discharge pipe, a light gas manifold and a cold trap, whereas the heavy gas (feed gas) is sent to the raw material supply stage. The product gas enriched in the raw material supply stage is mixed with waste gas discharged from another stage on the enriching side and flown into next separator. (Kamimura, M.)

  4. Nitrous oxide nitrification and denitrification 15N enrichment factors from Amazon forest soils.

    Science.gov (United States)

    Pérez, Tibisay; Garcia-Montiel, Diana; Trumbore, Susan; Tyler, Stanley; de Camargo, Plínio; Moreira, Marcelo; Piccolo, Marisa; Cerri, Carlos

    2006-12-01

    The isotopic signatures of 15N and 18O in N2O emitted from tropical soils vary both spatially and temporally, leading to large uncertainty in the overall tropical source signature and thereby limiting the utility of isotopes in constraining the global N2O budget. Determining the reasons for spatial and temporal variations in isotope signatures requires that we know the isotope enrichment factors for nitrification and denitrification, the two processes that produce N2O in soils. We have devised a method for measuring these enrichment factors using soil incubation experiments and report results from this method for three rain forest soils collected in the Brazilian Amazon: soil with differing sand and clay content from the Tapajos National Forest (TNF) near Santarém, Pará, and Nova Vida Farm, Rondônia. The 15N enrichment factors for nitrification and denitrification differ with soil texture and site: -111 per thousand +/- 12 per thousand and -31 per thousand +/- 11 per thousand for a clay-rich Oxisol (TNF), -102 per thousand +/- 5 per thousand and -45 per thousand +/- 5 per thousand for a sandier Ultisol (TNF), and -10.4 per thousand +/- 3.5 per thousand (enrichment factor for denitrification) for another Ultisol (Nova Vida) soil, respectively. We also show that the isotopomer site preference (delta15Nalpha - delta15Nbeta, where alpha indicates the central nitrogen atom and beta the terminal nitrogen atom in N2O) may allow differentiation between processes of production and consumption of N2O and can potentially be used to determine the contributions of nitrification and denitrification. The site preferences for nitrification and denitrification from the TNF-Ultisol incubated soils are: 4.2 per thousand +/- 8.4 per thousand and 31.6 per thousand +/- 8.1 per thousand, respectively. Thus, nitrifying and denitrifying bacteria populations under the conditions of our study exhibit significantly different 15N site preference fingerprints. Our data set strongly suggests that N2O isotopomers can be used in concert with traditional N2O stable isotope measurements as constraints to differentiate microbial N2O processes in soil and will contribute to interpretations of the isotopic site preference N2O values found in the free troposphere. PMID:17205894

  5. Job Enrichment and the Mentally Retarded Worker.

    Science.gov (United States)

    Morris, Jerry L.; And Others

    1981-01-01

    The effect of job enrichment on the production rate of 14 mentally retarded adult workers was evaluated. Job enrichment led to increases in standard rates of production for high IQ Ss and lower rates for low IQ Ss. (Author)

  6. Uranium enrichment (a strategy analysis overview)

    International Nuclear Information System (INIS)

    An analysis of available information on enrichment technology, separative work supply and demand, and SWU cost is presented. Estimates of present and future enrichment costs are provided for use in strategy analyses of alternate nuclear fuel cycles and systems. (auth)

  7. Evaluation of vitamin C-enriched Artemia nauplii for larvae of the giant freshwater prawn

    OpenAIRE

    Merchie, G.; Lavens, P.; Radull, J.; Nelis, H.; De Leenheer, A. P.; Sorgeloos, P.

    2000-01-01

    The effects of high levels of ascorbic acid (AA) delivered through enriched live food has been verified through the successful culture of larval giant freshwater prawn, Macrobrachium rosenbergii Two successive feeding trials were set up using a control (550 µg AA g-1 DW) and two different AA-enrichment levels in Artemia (1300 and 2750 µg AA g-1 DW). Under standard culture conditions, no differences in growth nor survival could be observed demonstrating that the nutritional requirements are be...

  8. Enriched uranium sales: effect on supply industry

    International Nuclear Information System (INIS)

    The subject is covered in sections: introduction (combined effect of low-enriched uranium (LEU) inventory sales and utility services enrichment contract terms); enrichment market overview; enrichment market dynamics; the reaction of the US Department of Energy; elimination of artificial demand; draw down of inventories; purchase and sale of LEU inventories; tails assay option; unfulfilled requirements for U3O8; conclusions. (U.K.)

  9. Perspectives on Job Enrichment and Productivity.

    Science.gov (United States)

    Suojanen, Waino W., Ed.; And Others

    The book of reading focuses on the state of job enrichment in the United States today, as well as some of its international implications. Featured in the book are 20 selected working papers analyzing the development and use of job enrichment in various types of organizations, union response to job enrichment, and its outlook for the future. The…

  10. Urenco's contribution to the enrichment market

    International Nuclear Information System (INIS)

    The paper deals with the Present status of Urenco Enrichment Plants and Order Book, Urenco's future development, The Western World enrichment supply situation, Urenco's Policy on the reliability of enrichment supplies, and its contribution to a reliable, stable and competitive world enrichment market. Urenco's current plant capacity and forward committed expansion plans up to 1990 and its present position in the western world enrichment market are described. The application of Urenco's centrifuge technology to the enrichment of recycles uranium and the relevance of laser enrichment development to Urenco are discussed. The paper next discusses the structure and main characteristics of the major sectional markets of the western world enrichment market, i.e. particularly in the United States, Western Europe and Asia (Japan, Korea and Taiwan). Urenco's contractual approach regarding the reliability of enrichment supplies is discussed, it is shown that Urenco's development of the centrifuge process to the point of economic maturity, Urenco's establishment of a multi-national commercial enrichment organization, Urenco's achievement in the world enrichment market by a commercial and competitive approach, Urenco's preparedness to negotiate suitable supply arrangements including the establishment of plants in other market areas have vastly contributed to a stabilisation of the world enrichment market. (J.P.N.)

  11. Anaerobic degradation of benzene by enriched consortia with humic acids as terminal electron acceptors

    International Nuclear Information System (INIS)

    Highlights: ? Enriched consortia were able to couple the anaerobic degradation of benzene to the reduction of humic acids. ? Electron-equivalents derived from anaerobic benzene oxidation were highly recovered as reduced humic acids. ? Several species from classes ?-, ?- and ?-Proteobacteria were enriched during the anaerobic degradation of benzene. - Abstract: The anaerobic degradation of benzene coupled to the reduction of humic acids (HA) was demonstrated in two enriched consortia. Both inocula were able to oxidize benzene under strict anaerobic conditions when the humic model compound, anthraquinone-2,6-disulfonate (AQDS), was supplied as terminal electron acceptor. An enrichment culture originated from a contaminated soil was also able to oxidize benzene linked to the reduction of highly purified soil humic acids (HPSHA). In HPSHA-amended cultures, 9.3 ?M of benzene were degraded, which corresponds to 279 ± 27 micro-electron equivalents (?Eq) L-1, linked to the reduction of 619 ± 81 ?Eq L-1 of HPSHA. Neither anaerobic benzene oxidation nor reduction of HPSHA occurred in sterilized controls. Anaerobic benzene oxidation did not occur in soil incubations lacking HPSHA. Furthermore, negligible reduction of HPSHA occurred in the absence of benzene. The enrichment culture derived from this soil was dominated by two ?-Proteobacteria phylotypes. A benzene-degrading AQDS-reducing enrichment originated from a sediment sample showed the prevalence of different species from classes ?-, ?- and ?-Proteobacteria. The present study provides clear quantitative demonstration of anaerobic degradation of benzene coupled to the reduction of HA.

  12. Vegetation, soil and hydrology management influence denitrification activity and the composition of nirK-type denitrifier communities in a newly afforested riparian buffer.

    Science.gov (United States)

    Boz, Bruno; Mizanur Rahman, Md; Bottegal, Mariangela; Basaglia, Marina; Squartini, Andrea; Gumiero, Bruna; Casella, Sergio

    2013-09-25

    Soil microbial community composition and activity could be affected by suitable manipulation of the environment they live in. If correctly applied such an approach could become a very effective way to remediate excess of chemicals. The concentration of nitrogen, especially nitrate deriving from agricultural managements, is generally found to increase in water flow. Therefore, by forcing the water flow through a buffer strip specifically designed and possibly afforested with suitable plant species, may result effective in reducing high nitrogen contents. The management of a riparian buffer may definitely affect the soil microbial activities, including denitrification, as well as the composition of the community. The present study reports on the changes occurred in terms of denitrifying microbial community composition, as compared to that of a neighbouring agricultural area, as a consequence of hydraulic management coupled to the suspension of farming practices and to the development of the woody and herbaceous vegetation. With this aim, denitrification was repeatedly measured and the data obtained were related to those deriving from a specific analysis of bacterial groups involved in denitrification. nirK, encoding for nitrite reductase, an enzyme essential for the conversion of nitrite to nitric oxide and considered the key step in the denitrification process, was chosen as the target gene. The main results obtained indicated that denitrification activity changes in riparian buffer as compared to agricultural soil and it is strongly influenced by carbon availability and soil depth. Although no significant differences on the community composition between superficial (0-15 cm) and medium (40-55 cm) layers were observed, the nirK-type denitrifier community was shown to significantly differ between riparian and agricultural soils in both surface and medium layers. PMID:23567981

  13. Diversity and distribution of amoA-type nitrifying and nirS-type denitrifying microbial communities in the Yangtze River estuary

    Science.gov (United States)

    Zhang, Y.; Xie, X.; Jiao, N.; Hsiao, S. S.-Y.; Kao, S.-J.

    2014-04-01

    Coupled nitrification-denitrification plays a critical role in the removal of excess nitrogen, which is chiefly caused by humans, to mitigate estuary and coastal eutrophication. Despite its obvious importance, limited information about the relationships between nitrifying and denitrifying microbial communities in estuaries, and their controlling factors have been documented. We investigated the nitrifying and denitrifying microbial communities in the estuary of turbid subtropical Yangtze River (YRE), the largest river in Asia, by analyzing the ammonia monooxygenase gene amoA, including archaeal and bacterial amoA, and the dissimilatory nitrite reductase gene nirS using clone libraries and quantitative PCR (qPCR). The diversity indices and rarefaction analysis revealed a quite low diversity for both ?-proteobacterial and archaeal amoA genes, but qPCR data showed significantly higher amoA gene copy numbers for archaea than ?-proteobacteria. Compared with the amoA gene, a significantly higher level of diversity but lower gene copy numbers were found for the nirS gene. Nitrification and denitrification rates based on 15N incubation experiments supported gene abundance data as denitrification rates were below detection limit, suggesting lower denitrification than nitrification potential. In general, the abundances of the amoA and nirS genes were significantly higher in the bottom samples than the surface ones, and in the high-turbidity river mouth, were significantly higher in the particle-associated (> 3 ?m) than the free-living (0.2 ~ 3 ?m) communities. Notably, positive correlations between the amoA and nirS gene abundances suggested potential gene-based coupling between nitrification and denitrification, especially for the particle-associated assemblages. Statistical analysis of correlations between the community structure, gene abundances and environmental variables further revealed that dissolved oxygen and total suspended material might be the key factors controlling community spatial structure and regulating nitrification and denitrification potentials in the YRE ecosystem.

  14. Nematode Indicators of Organic Enrichment

    Science.gov (United States)

    Ferris, Howard; Bongers, Tom

    2006-01-01

    The organisms of the soil food web, dependent on resources from plants or on amendment from other sources, respond characteristically to enrichment of their environment by organic matter. Primary consumers of the incoming substrate, including bacteria, fungi, plant-feeding nematodes, annelids, and some microarthropods, are entry-level indicators of enrichment. However, the quantification of abundance and biomass of this diverse group, as an indicator of resource status, requires a plethora of extraction and assessment techniques. Soluble organic compounds are absorbed by bacteria and fungi, while fungi also degrade more recalcitrant sources. These organisms are potential indicators of the nature of incoming substrate, but current methods of biomass determination do not reliably indicate their community composition. Guilds of nematodes that feed on bacteria (e.g., Rhabditidae, Panagrolaimidae) and fungi (e.g., Aphelenchidae, Aphelenchoididae) are responsive to changes in abundance of their food. Through direct herbivory, plant-feeding nematodes (e.g., many species of Tylenchina) also contribute to food web resources. Thus, analysis of the nematode community of a single sample provides indication of carbon flow through an important herbivore channel and through channels mediated by bacteria and fungi. Some nematode guilds are more responsive than others to resource enrichment. Generally, those bacterivores with short lifecycles and high reproductive potential (e.g., Rhabditidae) most closely mirror the bloom of bacteria or respond most rapidly to active plant growth. The feeding habits of some groups remain unclear. For example, nematodes of the Tylenchidae may constitute 30% or more of the individuals in a soil sample; further study is necessary to determine which resource channels they portray and the appropriate level of taxonomic resolution for this group. A graphic representation of the relative biomass of bacterivorous, fungivorous, and herbivorous nematodes provides a useful tool for assessing the importance of the bacterial, fungal, and plant resource channels in an extant food web. PMID:19259424

  15. Enrichment planting without soil treatment

    Energy Technology Data Exchange (ETDEWEB)

    Hagner, Mats

    1998-12-31

    Where enrichment planting had been carried out with either of the two species Picea abies and Pinus contorta, the survival of the planted seedlings was at least as good as after planting in a normal clear cut area treated with soil scarification. This was in spite of the fact that the seedlings were placed shallow in the humus layer without any soil treatment. However, they were sheltered from insects by treatment before planting. Where enrichment planting was carried out with Pinus sylvestris the survival in dense forest was poor, but in open forest the survival was good. The growth of planted seedlings was enhanced by traditional clearing and soil treatment. However, this was for Pinus sylvestris not enough to compensate for the loss of time, 1-2 years, caused by arrangement of soil scarification. The growth of seedlings planted under crown cover was directly related to basal area of retained trees. However, the variation in height growth among individual seedlings was very big, which meant that some seedlings grow well also under a fairly dense forest cover. The pioneer species Pinus sylvestris reacted more strongly to basal area of retained trees than did the shade tolerant species Picea abies. Enrichment planting seems to be a necessary tool for preserving volume productivity, at places where fairly intensive harvest of mature trees has been carried out in stands of ordinary forest type in central Sweden. If double seedlings, with one Picea abies and one Pinus sylvestris, are used, the probability for long term establishment is enhanced 13 refs, 20 figs, 4 tabs

  16. EMIS: Enrichment Management Information System

    International Nuclear Information System (INIS)

    The objective of the effort was the development of a calculational tool which would permit DOE to make realistic projections of the separative work demands of its customers as an aid in planning for the future operation of the enrichment facilities. The calculational methods were to recognize the flexibility in scheduling, etc., available to DOE customers under their enrichment contreacts as well as the ability to pool separative work withdrawn under two or more contracts. It was also to be designed to permit the user to add new customers or delete existing contracts as well as to allow variation of the estimated start-up dates for those reactors currently under construction. The output of the model was to display projections of separative work demand as SWU and in triplet form for several categories of reactors. These included, in addition to the total demand on the enrichment complex, separate totals for domestic and foreign customers, for reactors with Requirements and Adjustable Fixed Commitment contracts and for reactors in operation, under construction and projected new reactors designated by the user. The foundations upon which the system is based are described in this report. This includes a discussion of the available alternatives for customer management of separative work and the assumptions and guidelines established for development of the model. The report also contains a description of the computational procedures used in the model, and a description of the EMIS system itself, which also serves as a users' manual for the code. Finally, samples demonstrating the use of the system and indicating the form of the input and output are included

  17. Development of enrichment measurement technologies at the Ningyo-Toge uranium enrichment pilot plant

    International Nuclear Information System (INIS)

    The enrichment measurement of UF6 is one of the most important techniques for a gas centrifuge enrichment plant. Developments of enrichment measurements using non-destructive assay technologies have been carried out at the Ningyo-Toge Uranium Enrichment Pilot Plant, PNC. Included in these developments are an enrichment monitor on 30B type cylinders, a neutron monitor, in-line enrichment monitors, and those for pipework and for sample bottles, and the field test of the IAEA gas phase enrichment monitor. The evaluation applications of these monitors, used for both safeguards and process control, are described. (author)

  18. Producing deuterium-enriched products

    International Nuclear Information System (INIS)

    A method of producing an enriched deuterium product from a gaseous feed stream of mixed hydrogen and deuterium, comprises: (a) combining the feed stream with gaseous bromine to form a mixture of the feed stream and bromine and exposing the mixture to an electrical discharge effective to form deuterium bromide and hydrogen bromide with a ratio of D/H greater than the ratio of D/H in the feed stream; and (b) separating at least a portion of the hydrogen bromide and deuterium bromide from the mixture. (author)

  19. Boron enrichment in martian clay.

    Science.gov (United States)

    Stephenson, James D; Hallis, Lydia J; Nagashima, Kazuhide; Freeland, Stephen J

    2013-01-01

    We have detected a concentration of boron in martian clay far in excess of that in any previously reported extra-terrestrial object. This enrichment indicates that the chemistry necessary for the formation of ribose, a key component of RNA, could have existed on Mars since the formation of early clay deposits, contemporary to the emergence of life on Earth. Given the greater similarity of Earth and Mars early in their geological history, and the extensive disruption of Earth's earliest mineralogy by plate tectonics, we suggest that the conditions for prebiotic ribose synthesis may be better understood by further Mars exploration. PMID:23762242

  20. DOE enrichment plant hums ahead

    International Nuclear Information System (INIS)

    The Department of Energy's $10-billion gas centrifuge uranium enrichment plant, after three years of construction, is rising on schedule near Piketon, Ohio. A detailed conceptual design, smart management, liberal design fees, hungry contractors and cooperative unions are combining to get the job done. One reason for completing the task is that this will be a far more efficient process - 135 MW will be required to operate the centrifuge plant vs more than 2100 MW to produce the same amount of fuel at the mile-square diffusion plant near Portsmouth, Ohio

  1. Environmental enrichment for primates in laboratories

    Science.gov (United States)

    Buchanan-Smith, H. M.

    2010-06-01

    Environmental enrichment is a critical component of Refinement, one of the 3Rs underlying humane experimentation on animals. In this paper I discuss why primates housed in laboratories, which often have constraints of space and study protocols, are a special case for enrichment. I outline a framework for categorising the different types of enrichment, using the marmoset as a case study, and summarise the methods used to determine what animals want/prefer. I briefly review the arguments that enrichment does not negatively affect experimental outcomes. Finally I focus on complexity and novelty, choice and control, the underlying features of enrichment that makes it successful, and how combined with a thorough understanding of natural history we can put effective enrichment into practice in laboratories. Throughout the paper I emphasise the need to evaluate enrichment to ensure it is having the desired effect.

  2. Using Salt-Enriched Diets to Reduce Stress in Trout

    Directory of Open Access Journals (Sweden)

    Amanda E. Smith

    2005-01-01

    Full Text Available Chronically stressful conditions in fish culture facilities can lead to outbreaks of disease and reductions in growth and performance. A secondary response to stress in fish is the sudden and significant loss of plasma chloride ions, a condition known as hypochloremia. This loss of plasma chloride has been implicated as a cause of mortality in severely stressed fish. The effect of increased dietary salt on reducing hypochloremia in rainbow trout (Onchorynchus mykiss subjected to a confinement challenge was investigated. Experimental diets included added NaCl or CaCl2. Trout fed salt-enriched diets suffered less hypochloremia in the early hours or confinement. Trout fed a higher level of NaCl had significantly higher recovery plasma chloride levels post-stress. Salt-enriched diets containing moderate levels of NaCl may offer some benefit in recovering trout that have been exposed to stress.

  3. Fecal culture

    Science.gov (United States)

    Stool culture; Culture - stool ... stool tests are done in addition to the culture, such as: Gram stain of stool Fecal smear ... RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods . 22nd ed. Philadelphia, PA: Saunders ...

  4. Business History : A Cultural and Narrative Approach

    DEFF Research Database (Denmark)

    Hansen, Per H.

    2012-01-01

    This article argues that a cultural and narrative perspective can enrich the business history field, encourage new and different questions and answers, and provide new ways of thinking about methods and empirical material. It discusses what culture is and how it relates to narratives. Taking a cultural and narrative approach may affect questions, sources, and methodologies, as well as the status of our results. Finally, a narrative approach may contribute to our historical understanding of entrepreneurship and globalization.

  5. Using metagenomic analyses to estimate the consequences of enrichment bias for pathogen detection

    Directory of Open Access Journals (Sweden)

    Pettengill James B

    2012-07-01

    Full Text Available Abstract Background Enriching environmental samples to increase the probability of detection has been standard practice throughout the history of microbiology. However, by its very nature, the process of enrichment creates a biased sample that may have unintended consequences for surveillance or resolving a pathogenic outbreak. With the advent of next-generation sequencing and metagenomic approaches, the possibility now exists to quantify enrichment bias at an unprecedented taxonomic breadth. Findings We investigated differences in taxonomic profiles of three enriched and unenriched tomato phyllosphere samples taken from three different tomato fields (n?=?18. 16S rRNA gene meteganomes were created for each of the 18 samples using 454/Roche’s pyrosequencing platform, resulting in a total of 165,259 sequences. Significantly different taxonomic profiles and abundances at a number of taxonomic levels were observed between the two treatments. Although as many as 28 putative Salmonella sequences were detected in enriched samples, there was no significant difference in the abundance of Salmonella between enriched and unenriched treatments. Conclusions Our results illustrate that the process of enriching greatly alters the taxonomic profile of an environmental sample beyond that of the target organism. We also found evidence suggesting that enrichment may not increase the probability of detecting a target. In conclusion, our results further emphasize the need to develop metagenomics as a validated culture independent method for pathogen detection.

  6. Safeguards Culture

    Energy Technology Data Exchange (ETDEWEB)

    Frazar, Sarah L.; Mladineo, Stephen V.

    2012-07-01

    The concepts of nuclear safety and security culture are well established; however, a common understanding of safeguards culture is not internationally recognized. Supported by the National Nuclear Security Administration, the authors prepared this report, an analysis of the concept of safeguards culture, and gauged its value to the safeguards community. The authors explored distinctions between safeguards culture, safeguards compliance, and safeguards performance, and evaluated synergies and differences between safeguards culture and safety/security culture. The report concludes with suggested next steps.

  7. Organizational Culture

    Directory of Open Access Journals (Sweden)

    Adrian HUDREA

    2006-02-01

    Full Text Available Cultural orientations of an organization can be its greatest strength, providing the basis for problem solving, cooperation, and communication. Culture, however, can also inhibit needed changes. Cultural changes typically happen slowly – but without cultural change, many other organizational changes are doomed to fail. The dominant culture of an organization is a major contributor to its success. But, of course, no organizational culture is purely one type or another. And the existence of secondary cultures can provide the basis for change. Therefore, organizations need to understand the cultural environments and values.

  8. Enrichment and specific quantification of Methanocalculus in anaerobic digestion.

    Science.gov (United States)

    Chen, Si; He, Qiang

    2015-12-01

    Members of the genus Methanocalculus are characterized as hydrogenotrophic methanogens and present in diverse natural and engineered environments. Methanocalculus populations were enriched from anaerobic digesters treating dairy waste using formate as the substrate. Methanocalculus sequences retrieved from the enrichment cultures were subsequently used to develop a Methanocalculus-specific TaqMan qPCR assay to determine the abundance of Methanocalculus populations in the environment, representing the first quantitative tool specifically targeting Methanocalculus. The Methanocalculus-specific primer/probe set was shown to have high coverage with perfect match to >80% of all Methanocalculus 16S rRNA gene sequences in the Ribosomal Database Project (RDP). High specificity of the qPCR assay was also validated by both in silico and experimental analyses. Amplification efficiency of the qPCR assay was determined to be 91.9%, which is satisfactory for quantitative applications. Results from the Methanocalculus-specific qPCR analysis of formate-enriched methanogenic cultures were consistent with those from clone library analysis of the same cultures, validating the accuracy of the qPCR assay. Subsequent field application of the qPCR assay found low relative abundance of Methanocalculus in anaerobic digesters treating dairy waste, accounting for 0.01% of the archaeal populations. The qPCR results were consistent with the lack of detection of Methanocalculus in previous studies of the same anaerobic digesters with clone library analyses, which are less sensitive than qPCR. Thus, the Methanocalculus-specific qPCR assay developed in this study is a highly sensitive tool for the rapid and efficient quantification of Methanocalculus populations in methanogenic environments and understanding of the ecological functions of these methanogens. PMID:26059102

  9. Classification of positive blood cultures

    DEFF Research Database (Denmark)

    Gradel, Kim O; Knudsen, Inge Jenny Dahl; Arpi, Rolf Magnus; Ostergaard, Christian; Schønheyder, Henrik Carl; Søgaard, Mette

    2012-01-01

    ABSTRACT: BACKGROUND: Information from blood cultures is utilized for infection control, public health surveillance, and clinical outcome research. This information can be enriched by physicians assessments of positive blood cultures, which are, however, often available from selected patient groups...... or pathogens only. The aim of this work was to determine whether patients with positive blood cultures can be classified effectively for outcome research in epidemiological studies by the use of administrative data and computer algorithms, taking physicians assessments as reference. METHODS......: Physicians assessments of positive blood cultures were routinely recorded at two Danish hospitals from 2006 through 2008. The physicians assessments classified positive blood cultures as: a) contamination or bloodstream infection; b) bloodstream infection as mono- or polymicrobial; c) bloodstream infection...

  10. Gasket for uranium enrichment plant

    International Nuclear Information System (INIS)

    Purpose: To obtain a gasket to be inserted between flange joints in the equipments and pipe lines of an uranium enrichment plant having neither permeability nor adsorptivity to water while maintaining mechanical, physical and chemical properties of an elastomer gasket. Constitution: A gasket made of an elastomeric material such as a polymer is integratedly formed at its surface with anti-slip projections. The gasket is further surrounded at its upper and lower peripheral sides, as well as outer circumferential portion with an U-sectioned cover (enclosure) made of fluoro-plastics. In this arrangement, the gasket main body shows a gas-tightness for uranium hexafluoride gas and the cover exhibits a gas-tightness for other component gases such as moisture to thereby prevent degradation of the gasket due to absorption and permeation of the moisture. (Furukawa, Y.)

  11. Enriched natural zeolites ? mineral fertilizer

    Directory of Open Access Journals (Sweden)

    Rybárová Lucia

    2001-12-01

    Full Text Available Clinoptilolit belongs to the big group of minerals called zeolites. Chemically they are alumosilicates and have a very difficult crystal structure. Nature zeolites are used as sorbents, molecular sieves and catalyzators. Their application is also in agriculture and horticulture. Endeavour of all agricurtural subjects from the plant area is to reach a maximum efficiency and production.Charges for the fertilization are 14 ? 40% of all charges depending on the structure of product, intensity of production and share of nutrition in soil. For the elimination of the loss in the nutrition matter, it is possible to use a ?porter?, which secures a regular and inteligent supply of nutrition to plants.Regarding the physical and chemical properties is good to use natural zeolites as a ?porter?.The experiments were made with enriched zeolites, and their influences an vegetables and flowers roots was reserched. Results were positive.

  12. Uranium enrichment and the environment

    International Nuclear Information System (INIS)

    The three gaseous diffusion plants comprise one of the largest industrial complexes in the free world. Since all of the enrichment is done inside a very large plumbing maze, the control of radioactivity does not present a serious problem. Conventional, nonexotic engineering and administrative measures adequately control the minor levels of radioactivity associated with support activities such as equipment decontamination and maintenance. The treatment and control of chemical waste streams to comply with Federal and state regulations has required the commitment of 47 million dollars since 1974. Through 1982, an additional 84 million dollars may be required. The high cost is not a reflection of initially poor conditions but is rather the result of providing large treatment systems to meet very low discharge limits. Examples that will be discussed include airborne particulate removal, recirculating cooling water treatment, and hazardous waste disposal concepts

  13. Enrichment of carbon monoxide utilising microorganisms from methanogenic bioreactor sludge

    OpenAIRE

    Pereira, Ana Luísa; A. J. M. Stams; Alves, M. M.; Sousa, D. Z.

    2015-01-01

    Conversion of CO is the rate limiting step during anaerobic conversion of syngas (a gaseous mixture mainly composed of CO, CO2 and H2). In this work we study the microbial diversity in anaerobic sludge submitted to extended contact to syngas in a multi-orifice baffled bioreactor (MOBB). Methane was the main product resulting from syngas conversion in the MOBB. Enrichment cultures started with this sludge produced methane as final product, but also acetate. 16S rRNA gene analysis revealed a pr...

  14. IPNS enriched uranium booster target

    International Nuclear Information System (INIS)

    Since startup in 1981, IPNS has operated on a fully depleted 238U target. With the booster as in the present system, high energy protons accelerated to 450 MeV by the Rapid Cycling Synchrotron are directed at the target and by mechanisms of spallation and fission of the uranium, produce fast neutrons. The neutrons from the target pass into adjacent moderator where they slow down to energies useful for spectroscopy. The target cooling systems and monitoring systems have operated very reliably and safely during this period. To provide higher neutron intensity, we have developed plans for an enriched uranium (booster) target. HETC-VIM calculations indicate that the target will produce approx.90 kW of heat, with a nominal x5 gain (k/sub eff/ = 0.80). The neutron beam intensity gain will be a factor of approx.3. Thermal-hydraulic and heat transport calculations indicate that approx.1/2 in. thick 235U discs are subject to about the same temperatures as the present 238U 1 in. thick discs. The coolant will be light demineralized water (H2O) and the coolant flow rate must be doubled. The broadening of the fast neutron pulse width should not seriously affect the neutron scattering experiments. Delayed neutrons will appear at a level about 3% of the total (currently approx.0.5%). This may affect backgrounds in some experiments, so that we are assessing measures to control and correct for this (e.g., beam tube choppers). Safety analyses and neutronic calculations are nearing completion. Construction of the 235U discs at the ORNL Y-12 facility is scheduled to begin late 1985. The completion of the booster target and operation are scheduled for late 1986. No enriched uranium target assembly operating at the projected power level now exists in the world. This effort thus represents an important technological experiment as well as being a ''flux enhancer''

  15. Enrichment of chromium isotopes by gas centrifugation

    Science.gov (United States)

    Szady, A. J.

    1989-10-01

    Recently, chromium isotopes have been enriched using gas centrifuges that were developed by the United States Department of Energy for the purpose of enriching uranium in the fissionable isotope 235U. The process gas employed was chromyl-fluoride. The enrichment was carried out using a single gas centrifuge that was set up to emphasize the enrichment of the light isotope 50Cr, which has a natural abundance of 4.35%. The highest enrichment tested to date is 21.4%. Higher values are possible with additional repasses. The heavy isotope 54Cr can be enriched instead of the 50Cr with an adjustment to the machine flows. Currently, work is under way to refine the cost projections associated with feed production and conversion back to an oxide and to optimize the centrifuge separative performance.

  16. Industrial cultures

    DEFF Research Database (Denmark)

    Rasmussen, Lauge Baungaard

    The chapter deals with different paradigms andtheories of cultural development. The problem toexplain change and methods to analyse developmentin different cultures are presented and discussed.......The chapter deals with different paradigms andtheories of cultural development. The problem toexplain change and methods to analyse developmentin different cultures are presented and discussed....

  17. Learning Culture.

    Science.gov (United States)

    Jones, David

    Adult and continuing education in the arts can and does play a role in the development of cultural identity. Dimensions of culture include ethnicity, location, age, social class, and time. This definition of culture leads to the conclusion that cultures are generally small and are dynamic rather than static. Research shows that individuals in what…

  18. EURODIF: the uranium enrichment by gaseous diffusion

    International Nuclear Information System (INIS)

    During the seventies the nuclear power programme had an extremely rapid growth rate which entailed to increase the world uranium enrichment capacity. EURODIF is the largest undertaking in this field. This multinational joint venture built and now operates and enrichment plant using the gaseous diffusion process at Tricastin (France). This plant is delivering low enriched uranium since two years and has contracted about 110 million SWU's till 1990. Description, current activity and prospects are given in the paper. (Author)

  19. Uranium Enrichment Associates - a private initiative

    International Nuclear Information System (INIS)

    The status of the activities of Uranium Enrichment Associates, a private organisation for the production of enriched uranium, is described. The issues involved in deciding upon gaseous diffusion as the process to be adopted are considered. Plans for financing the project, the method of costing for enrichment, and marketing prospects are described. The structure of the organisation and its relations with the US government are also discussed. (U.K.)

  20. Extended Finite Element Method with Global Enrichment

    OpenAIRE

    Agathos, Konstantinos; Chatzi, Eleni; Bordas, Stéphane; Talaslidis, Demosthenes

    2015-01-01

    A variant of the extended finite element method is presented which facilitates the use of enriched elements in a fixed volume around the crack front (geometrical enrichment) in 3D fracture problems. The major problem associated with geometrical enrichment is that it significantly deteriorates the conditioning of the resulting system matrices, thus increasing solution times and in some cases making the systems unsolvable. For 2D problems this can be dealt with by employing degree of freedom ga...

  1. Environmental enrichment in farm, zoo, companion and experimental animals

    Directory of Open Access Journals (Sweden)

    Vu?ini? Marijana

    2009-01-01

    Full Text Available The paper deals with environmental enrichment for domestic animals at farms, animals in zoos, experimental animals and pet animals. Also, the paper defines and describes different strategies of environmental enrichment. Environmental enrichment is a simple and effective mean of prevention of boredom, behavioral disorders as well as an effective mean of improving animal welfare in farm, zoo, companion and experimental animals. Different items and materials may be used for environmental enrichment. They need to be evaluated for use by taking into account the following: the species of an animal, its needs, habits and capabilities, the type of an enrichment device, the device's ability to stimulate the animal's interest and the safety of the device. Enrichment programmes should always include two forms of enrichment: behavioral enrichment and environmental enrichment. Enrichment comes in many forms such as structural or physical enrichment, sensory enrichment (auditory and olfactory stimulation, dietary enrichment, manipulatable enrichment and social enrichment.

  2. Evaluación del crecimiento de un cultivo de Daphnia magna alimentado con Saccharomyces cereviseae y un enriquecimiento con avena soya / Growth culture evaluation of Daphnia magna feed with Saccharomyces cereviseae enrichment with oat soy / Avaliação do crescimento de um cultivo de Daphnia magna alimentada con Saccharomyces cereviseae e um meio enrriquecido com aveia soja

    Scientific Electronic Library Online (English)

    Lucía E, Ocampo; Mónica C, Botero; Luis F, Restrepo.

    2010-03-01

    Full Text Available O objetivo do experimento foi avaliar o efeito das gorduras saturadas e insaturadas e seu grau de proteção (protegidas e sem proteção) sob a cinética e a extensão da degradação in vitro da matéria seca (MS) em dietas para ruminantes. Quatro dietas foram formuladas para conter o mesmo nível de energi [...] a (3200 Kcal ED /Kg MS) e proteína (13%PC) a ração total misturada (RTM), de acordo com as necessidades nutricionais de ovelhas em fase de finalização, quatro tipos de gorduras foram feitas com 8% de MS e foram testados tipos de gorduras foram testados: 1) gordura saturada sem proteção (GSSP), 2) gordura saturada protegida (GSP), 3) gordura insaturada sem proteção (GISP) e 4) gordura insaturada protegida (GIP). Para estimar a cinética e a extensão da degradação da MS e cinética da produção de gás, as rações foram avaliadas mediante a técnica in vitro de produção de gás, seguindo os modelos propostos por Orskov e McDonald (1979) y France et al (1993), para isto foi empregado o procedimento PROC NLIN de SAS (2001). Ao mesmo tempo, foi realizado um analise de medidas repetidas no tempo para verificar o efeito dos tratamentos sobre a produção de gás e a degradação da MS no tempo com ajuda do procedimento PROC MIXED do SAS (2001.) Neste experimento verificou-se que a utilização de gorduras insaturadas protegidas não afetou a degradação de MS quando comparadas com as não protegidas. No caso das gorduras saturadas, não houve um claro efeito da proteção sob a degradação e a cinética de fermentação da MS. Abstract in spanish Se realizó el cultivo experimental de cladócero Daphnia magna alimentado con probióticos. Se realizaron 16 ensayos experimentales, en el laboratorio de larvicultura de peces y alimento vivo (Larpeali) de la Facultad de Ciencias Agrarias de la Universidad de Antioquia, bajo condiciones controladas de [...] temperatura ambiente (21 - 25 °C), temperatura del agua (22 - 23 °C) y pH (7.6). Empleando una dieta de Saccharomyces cereviseae y un medio de enriquecimiento con ácidos grasos (n-6) proveniente de harina avena-soya. Las concentraciones de dieta y enriquecimiento fueron de 25 ppm y 12.5 ppm, en arreglo factorial 2x2 (2 niveles de dieta con levadura y 2 niveles dieta con avena de soya), los cultivos de Daphnia por tratamiento se realizaron con cuatro replicas con el fin de determinar su efecto sobre el desempeño de la población. Se alimentaron cada tercer día, durante 15 días, evaluándose el número de organismos al final del período. Se obtuvieron diferencias altamente significativas (p0.05). Se evidenció que la combinación de estos componentes en sus concentraciones más altas potenció el crecimiento de la Daphnia magna, alcanzando un número de microcrustáceos de 826ª Daphnias/L ± 9.57. Se puede concluir que los cladóceros por sus características de crecimiento en cultivo, presentan adaptación favorable a las condiciones de manejo para la producción de biomasa útil como alimento vivo en acuicultura. Abstract in english Experimental cultivate cladocerans Daphnia magna feed with probiotics was realized. At University of Antioquia, Faculty of Agrarian Science, Larviculture, fish and food live Laboratory (Larpeali), under controlled conditions of environmental temperature between (21 - 25 °C), water temperature (22 - [...] 23°C) and pH (7.6), were performed. One diet of Saccharomyces cereviseae was used and one enriched medium of oat-soy flour (fatty acid, n-6) to concentrations of diet and enriched medium were the same, 25 ppm and 12.5 ppm, 2x2 factorial treatment arrangements (2 levels of Saccharomyces cereviseae and 2 levels of oat-soy flour, diets was fed to four replicates of Daphnia culture per treatment in order to determine their effects on the populations cultivated. A 15-days feeding, each third day, trial were conducted, to assess the organisms at final period. The results showed significant high difference (p0.05). The results showed that the combination of their high concentrations of components enhan

  3. Evaluación del crecimiento de un cultivo de Daphnia magna alimentado con Saccharomyces cereviseae y un enriquecimiento con avena soya Avaliação do crescimento de um cultivo de Daphnia magna alimentada con Saccharomyces cereviseae e um meio enrriquecido com aveia soja Growth culture evaluation of Daphnia magna feed with Saccharomyces cereviseae enrichment with oat soy

    Directory of Open Access Journals (Sweden)

    Lucía E Ocampo

    2010-03-01

    Full Text Available Se realizó el cultivo experimental de cladócero Daphnia magna alimentado con probióticos. Se realizaron 16 ensayos experimentales, en el laboratorio de larvicultura de peces y alimento vivo (Larpeali de la Facultad de Ciencias Agrarias de la Universidad de Antioquia, bajo condiciones controladas de temperatura ambiente (21 - 25 °C, temperatura del agua (22 - 23 °C y pH (7.6. Empleando una dieta de Saccharomyces cereviseae y un medio de enriquecimiento con ácidos grasos (n-6 proveniente de harina avena-soya. Las concentraciones de dieta y enriquecimiento fueron de 25 ppm y 12.5 ppm, en arreglo factorial 2x2 (2 niveles de dieta con levadura y 2 niveles dieta con avena de soya, los cultivos de Daphnia por tratamiento se realizaron con cuatro replicas con el fin de determinar su efecto sobre el desempeño de la población. Se alimentaron cada tercer día, durante 15 días, evaluándose el número de organismos al final del período. Se obtuvieron diferencias altamente significativas (p0.05. Se evidenció que la combinación de estos componentes en sus concentraciones más altas potenció el crecimiento de la Daphnia magna, alcanzando un número de microcrustáceos de 826ª Daphnias/L ± 9.57. Se puede concluir que los cladóceros por sus características de crecimiento en cultivo, presentan adaptación favorable a las condiciones de manejo para la producción de biomasa útil como alimento vivo en acuicultura.O objetivo do experimento foi avaliar o efeito das gorduras saturadas e insaturadas e seu grau de proteção (protegidas e sem proteção sob a cinética e a extensão da degradação in vitro da matéria seca (MS em dietas para ruminantes. Quatro dietas foram formuladas para conter o mesmo nível de energia (3200 Kcal ED /Kg MS e proteína (13%PC a ração total misturada (RTM, de acordo com as necessidades nutricionais de ovelhas em fase de finalização, quatro tipos de gorduras foram feitas com 8% de MS e foram testados tipos de gorduras foram testados: 1 gordura saturada sem proteção (GSSP, 2 gordura saturada protegida (GSP, 3 gordura insaturada sem proteção (GISP e 4 gordura insaturada protegida (GIP. Para estimar a cinética e a extensão da degradação da MS e cinética da produção de gás, as rações foram avaliadas mediante a técnica in vitro de produção de gás, seguindo os modelos propostos por Orskov e McDonald (1979 y France et al (1993, para isto foi empregado o procedimento PROC NLIN de SAS (2001. Ao mesmo tempo, foi realizado um analise de medidas repetidas no tempo para verificar o efeito dos tratamentos sobre a produção de gás e a degradação da MS no tempo com ajuda do procedimento PROC MIXED do SAS (2001. Neste experimento verificou-se que a utilização de gorduras insaturadas protegidas não afetou a degradação de MS quando comparadas com as não protegidas. No caso das gorduras saturadas, não houve um claro efeito da proteção sob a degradação e a cinética de fermentação da MS.Experimental cultivate cladocerans Daphnia magna feed with probiotics was realized. At University of Antioquia, Faculty of Agrarian Science, Larviculture, fish and food live Laboratory (Larpeali, under controlled conditions of environmental temperature between (21 - 25 °C, water temperature (22 - 23°C and pH (7.6, were performed. One diet of Saccharomyces cereviseae was used and one enriched medium of oat-soy flour (fatty acid, n-6 to concentrations of diet and enriched medium were the same, 25 ppm and 12.5 ppm, 2x2 factorial treatment arrangements (2 levels of Saccharomyces cereviseae and 2 levels of oat-soy flour, diets was fed to four replicates of Daphnia culture per treatment in order to determine their effects on the populations cultivated. A 15-days feeding, each third day, trial were conducted, to assess the organisms at final period. The results showed significant high difference (p0.05. The results showed that the combination of their high concentrations of components enhanced the population growth of Daphnia magna, reaching a number of micr

  4. Fluxes in PHA-storing microbial communities during enrichment and biopolymer accumulation processes.

    Science.gov (United States)

    Janarthanan, Om Murugan; Laycock, Bronwyn; Montano-Herrera, Liliana; Lu, Yang; Arcos-Hernandez, Monica V; Werker, Alan; Pratt, Steven

    2016-01-25

    The use of mixed microbial cultures for the production of polyhydroxyalkanoates (PHAs) is emerging as a viable technology. In this study, 16S rRNA gene amplicon pyrosequencing was used to analyse fluctuations in populations over a 63-day period within a PHA-storing mixed microbial community enriched on fermented whey permeate. This community was dominated by the genera Flavisolibacter and Zoogloea as well as an unidentified organism belonging to the phylum Bacteroidetes. The population was observed to cycle through an increase in Zoogloea followed by a return to a community composition similar to the initial one (highly enriched in Flavisolibacter). It was found that the PHA accumulation capacity of the community was robust to population flux during enrichment and even PHA accumulation, with final polymer composition dependent on the overall proportion of acetic to propionic acids in the feed. This community adaptation suggests that mixed culture PHA production is a robust process. PMID:26257140

  5. Basic uranium-235 enrichment by the Asahi Chemical Enrichment Process (ACEP)

    International Nuclear Information System (INIS)

    The development of Asahi Chemical Enrichment Process (ACEP) led to the establishment of basic process technology permitting attainment of 3% enrichment within several months of operation by the mid-1980s, through advances which brought increased electron-exchange and adsorption-desorption reaction rates, effective uranium adsorption band formation and maintenance, and equilibrium plate height reductions based on the elucidation of mobile-phase dispersion. The theoretical and experimental development of redox agent self-regeneration led to a new 'Super Process' characterized by greater simplicity and efficiency than previously thought possible. A semi-commercial plant with enrichment columns of 1 m in diameter and 3 m in height, constructed at Hyuga City in Miyazaki Prefecture, demonstrated 3% uranium enrichment in April 1988. Through the improvement of enrichment efficiency, overall enrichment costs have been greatly lowered. The advantage of the chemical enrichment process, and its low cost of enrichment, have now been clearly demonstrated. (author)

  6. Ethyl tert-butyl ether (ETBE)-degrading microbial communities in enrichments from polluted environments.

    Science.gov (United States)

    Le Digabel, Yoann; Demanèche, Sandrine; Benoit, Yves; Fayolle-Guichard, Françoise; Vogel, Timothy M

    2014-08-30

    The ethyl tert-butyl ether (ETBE) degradation capacity and phylogenetic composition of five aerobic enrichment cultures with ETBE as the sole carbon and energy source were studied. In all cases, ETBE was entirely degraded to biomass and CO2. Clone libraries of the 16S rRNA gene were prepared from each enrichment. The analyses of the DNA sequences obtained showed different taxonomic compositions with a majority of Proteobacteria in three cases. The two other enrichments have different microbiota with an abundance of Acidobacteria in one case, whereas the microbiota in the second was more diverse (majority of Actinobacteria, Chlorobi and Gemmatimonadetes). Actinobacteria were detected in all five enrichments. Several bacterial strains were isolated from the enrichments and five were capable of degrading ETBE and/or tert-butyl alcohol (TBA), a degradation intermediate. The five included three Rhodococcus sp. (IFP 2040, IFP 2041, IFP 2043), one Betaproteobacteria (IFP 2047) belonging to the Rubrivivax/Leptothrix/Ideonella branch, and one Pseudonocardia sp. (IFP 2050). Quantification of these five strains and two other strains, Rhodococcus sp. IFP 2042 and Bradyrhizobium sp. IFP2049, which had been previously isolated from one of the enrichments was carried out on the different enrichments based on quantitative PCR with specific 16S rRNA gene primers and the results were consistent with the hypothesized role of Actinobacteria and Betaproteobacteria in the degradation of ETBE and the possible role of Bradyrhizobium strains in the degradation of TBA. PMID:25108826

  7. Use of an Interculturally Enriched Collaboration Script in Computer-Supported Collaborative Learning in Higher Education

    Science.gov (United States)

    Popov, Vitaliy; Biemans, Harm J. A.; Kuznetsov, Andrei N.; Mulder, Martin

    2014-01-01

    In this exploratory study, the authors introduced an interculturally enriched collaboration script (IECS) for working in culturally diverse groups within a computer-supported collaborative learning (CSCL) environment and then assessed student online collaborative behaviour, learning performance and experiences. The question was if and how these…

  8. Virtual Interaction through Video-Web Communication: A Step towards Enriching and Internationalizing Language Learning Programs

    Science.gov (United States)

    Jauregi, Kristi; Banados, Emerita

    2008-01-01

    This paper describes an intercontinental project with the use of interactive tools, both synchronous and asynchronous, which was set up to internationalize academic learning of Spanish language and culture. The objective of this case study was to investigate whether video-web communication tools can contribute to enriching the quality of foreign…

  9. EFFECTS OF NUTRIENT ENRICHMENT, LIGHT INTENSITY AND TEMPERATURE ON GROWTH OF PHYTOPLANKTON FROM LAKE HURON

    Science.gov (United States)

    This report contains a seasonal study on effects of nutrient enrichment, light and temperature on the growth of natural phytoplankton and three species of cultured diatoms. Natural phytoplankton assemblages collected monthly from April to December 1975, in southern Lake Huron wer...

  10. Decoding cultural landscapes: guiding principles for the management of interpretation in cultural world heritage sites

    OpenAIRE

    Kamel, Ehab

    2011-01-01

    Conserving the cultural significance of heritage sites - as the guardians of social unity, place identity, and national pride - plays an essential role in maintaining sustainable social development, as well as preserving the variations identifying cultural groups and enriching the interaction between them. Consequently, and considering the importance of the built environment in communicating, as well as documenting, cultural messages, this research project, started in 2007, develops a set of ...

  11. Cultural Neuroscience.

    Science.gov (United States)

    Ames, Daniel L; Fiske, Susan T

    2010-06-01

    Cultural neuroscience issues from the apparently incompatible combination of neuroscience and cultural psychology. A brief literature sampling suggests, instead, several preliminary topics that demonstrate proof of possibilities: cultural differences in both lower-level processes (e.g. perception, number representation) and higher-order processes (e.g. inferring others' emotions, contemplating the self) are beginning to shed new light on both culture and cognition. Candidates for future cultural neuroscience research include cultural variations in the default (resting) network, which may be social; regulation and inhibition of feelings, thoughts, and actions; prejudice and dehumanization; and neural signatures of fundamental warmth and competence judgments. PMID:23874143

  12. Student science enrichment training program

    Energy Technology Data Exchange (ETDEWEB)

    Sandhu, S.S.

    1994-08-01

    This is a report on the Student Science Enrichment Training Program, with special emphasis on chemical and computer science fields. The residential summer session was held at the campus of Claflin College, Orangeburg, SC, for six weeks during 1993 summer, to run concomitantly with the college`s summer school. Fifty participants selected for this program, included high school sophomores, juniors and seniors. The students came from rural South Carolina and adjoining states which, presently, have limited science and computer science facilities. The program focused on high ability minority students, with high potential for science engineering and mathematical careers. The major objective was to increase the pool of well qualified college entering minority students who would elect to go into science, engineering and mathematical careers. The Division of Natural Sciences and Mathematics and engineering at Claflin College received major benefits from this program as it helped them to expand the Departments of Chemistry, Engineering, Mathematics and Computer Science as a result of additional enrollment. It also established an expanded pool of well qualified minority science and mathematics graduates, which were recruited by the federal agencies and private corporations, visiting Claflin College Campus. Department of Energy`s relationship with Claflin College increased the public awareness of energy related job opportunities in the public and private sectors.

  13. Enriching the hot circumgalactic medium

    CERN Document Server

    Crain, Robert A; Schaye, Joop; Frenk, Carlos S; Theuns, Tom

    2013-01-01

    Models of galaxy formation in a CDM universe predict that massive galaxies are surrounded by a hot, quasi-hydrostatic circumgalactic corona of slowly cooling gas, predominantly accreted from the IGM. This prediction is borne out by the cosmological hydrodynamical simulations of Crain et al., which reproduce scaling relations between the X-ray and optical properties of nearby disc galaxies. Such coronae are metal poor, but observations of the X-ray emitting circumgalactic medium (CGM) of local galaxies typically indicate enrichment to near-solar iron abundance, potentially signalling a shortcoming in galaxy formation models. We show here that, while the hot CGM of galaxies formed in the simulations is metal poor in a mass-weighted sense, its X-ray luminosity-weighted metallicity is often close to solar. This bias arises because the soft X-ray emissivity of a typical 0.1 keV corona is dominated by collisionally-excited metal ions that are synthesised in stars and recycled into the hot CGM. We find that these me...

  14. Nutraceutical enriched Indian traditional chikki.

    Science.gov (United States)

    Ramakrishna, Chetana; Pamisetty, Aruna; Reddy, Sunki Reddy Yella

    2015-08-01

    Chikki or peanut brittle, a traditional sweet snack was chosen as vehicle for enrichment with added natural nutraceuticals through herbs. The formulation and process for preparation of chikki with added herbs like ashwagandha (Withania somenifera), tulasi (Ocimumsanctum L.) and ajwain (Trachyspermum ammi S.) were standardized. The polyphenol content of chikki with added herbs ranged 0.29-0.46 g/100 g. Among the herbs, ajwain showed more potent antioxidant activity followed by tulasi, whereas ashwagandha and product prepared with it showed the least activity. Total carotenoid contents of chikki with added herbs ranged between 1.5 and 4.3 mg/100 g. Storage studies showed that chikki prepared with tulasi and ajwain were sensorily acceptable up to 90 days, while rancid notes were observed in control and chikki with added ashwagandha at the end of 30 days. Thus chikki with added herbs in addition to containing natural nutraceuticals like polyphenols and carotenoids had improved storage stability compared to control. PMID:26243935

  15. Mortality among uranium enrichment workers

    International Nuclear Information System (INIS)

    A retrospective cohort mortality study was conducted on workers at the Portsmouth Uranium Enrichment facility in Pike County, Ohio, in response to a request from the Oil, Chemical and Atomic Workers International Local 3-689 for information on long-term health effects. Primary hazards included inhalation exposure to uranyl fluoride containing uranium-235 and uranium-234, technetium-99 compounds, and hydrogen-fluoride. Uranium-238 presented a nephrotoxic hazard. Statistically significant mortality deficits based on U.S. death rates were found for all causes, accidents, violence, and diseases of nervous, circulatory, respiratory, and digestive systems. Standardized mortality rates were 85 and 54 for all malignant neoplasms and for other genitourinary diseases, respectively. Deaths from stomach cancer and lymphatic/hematopoietic cancers were insignificantly increased. A subcohort selected for greatest potential uranium exposure has reduced deaths from these malignancies. Insignificantly increased stomach cancer mortality was found after 15 years employment and after 15 years latency. Routine urinalysis data suggested low internal uranium exposures

  16. 76 FR 11523 - Atomic Safety and Licensing Board; AREVA Enrichment Services, LLC (Eagle Rock Enrichment Facility...

    Science.gov (United States)

    2011-03-02

    ... Rock Enrichment Facility), 74 FR 38,052, 38,055 (Jul. 30, 2009) (CLI-09- 15, 70 NRC 1, 10-11 (2009... of Enrichment Facility Licensing Proceeding), 75 FR 63,213 (Oct. 14, 2010), which was the subject of... Interested Governmental Entities Regarding Environmental Portion of Enrichment Facility Licensing...

  17. 76 FR 53494 - In the Matter of United States Enrichment Corporation; Paducah Gaseous Enrichment Plant...

    Science.gov (United States)

    2011-08-26

    ... From the Federal Register Online via the Government Publishing Office NUCLEAR REGULATORY COMMISSION In the Matter of United States Enrichment Corporation; Paducah Gaseous Enrichment Plant; Confirmatory Order (Effective Immediately) I The United States Enrichment Corporation (USEC), a subsidiary of USEC Inc., is the holder of the United...

  18. Perspectives for the uranium enrichment in Brazil

    International Nuclear Information System (INIS)

    Through an analysis of the electrical energy future in Brazil, the needs for enriched uranium are discussed, and therefore the importance of developing local capability for self-production. A description of the production processes that are well established is given first, then the analysis itself is performed and finally a visualization of the International Market for enriched uranium is shown. (author)

  19. 21 CFR 137.350 - Enriched rice.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Enriched rice. 137.350 Section 137.350 Food and... Related Products § 137.350 Enriched rice. (a) The foods for which definitions and standards of identity are prescribed by this section are forms of milled rice (except rice coated with talc and glucose...

  20. Tritium enrichment of environmental waters by electrolysis

    International Nuclear Information System (INIS)

    In order to enrich the tritium in the water samples by minimum 10 times, we have developed a battery of 5 electrolysis cells. The procedure for electrolytic tritium enrichment of water requires that both isotopic fractionation during the sample treatment and contamination with other water, possibly of high 3H concentration, be excluded. The procedure includes, before the enrichment run, a primary distillation of the samples and after the enrichment a final distillation. During distillation the temperature should be about 150 deg C and the recovery of water total. We have used a method known from the literature for the estimation of the enrichment factor for the tritium content in the water samples after electrolysis (?) by means of the enrichment factor for the deuterium content (?) that is measured before and after the electrolysis by mass spectrometry. The tritium enrichment factor, ?, is determined by using the Bigeleisen relation, lg? = 1.41 lg?, in the limits of ±5% errors. In order to obtain a desired final volume in every cell we have developed a programmable electronic system that can interrupt the current through any cell in which the desired volume of electrolyte is attained. We have obtained an enrichment factor of 20 for the water samples after electrolysis. (author)

  1. Providing incentives to buy US enrichment

    International Nuclear Information System (INIS)

    The U.S. Department of Energy is making a series of commercial and technological decisions crucial to its future as an enriching enterprise. The state of US enrichment, as revealed in this years AIF Fuel Cycle conference, is reported. (U.K.)

  2. Uranium enrichment : global view and Brazilian perspectives

    International Nuclear Information System (INIS)

    A global view of isotope enrichment involving a general description of process (technical-economical aspects and policy) and status in developing countries is done. An enrichment demand in function of the Brazilian Nuclear Program is evaluated, analyzing a probable market and a low market. The perspectives to attend this demand, are studied. (E.G.)

  3. Study on the radiotoxicology of enriched uranium

    International Nuclear Information System (INIS)

    A study on the retentive peculiarity of soluble enriched uranium UO2F2 were observed after iv once or consecutive ip qd x 3d to Wistar male rats. The dynamic retention of radioactivity in the body showed that the enriched uranium UO2F2 was chiefly localized in kidney, and then in skeleton and liver. The radioactivity of the enriched uranium UO2F2 in skeleton rose steadily while the concentratoin in kidney and liver droped. When enriched uranium UO2F2 was accumulated in organism, it caused chromosome aberrations on bone marrow cells. Results indicated that the chromosome aberration rates were elevated when the dose of the enriched uranium UO2F2 was increased, at the same time, the cell division was depressed. Accumulation of insoluble enriched uranium U3O8 in gastrointestinal tract was well described by a two exponential expression. Values of retention estimate for fast component, T1 = 0.34 d, and for relatively long term component, T2 = 4.05 d. The deposition of UO2F2 in the intact skin was only 0.16 to 0.18% of the total contaminated UO2F2. Penetration of the enriched uranium UO2F2 was dominantly increased in abraded skin. This value is about 25 to 32 times as compaired with that in intact skin. Retention of the enriched uranium UO2F2 through abraded skins was dominantly localized in kidney and skeleton

  4. A Duality of Quantale-Enriched Categories

    OpenAIRE

    Hofmann, Dirk; Waszkiewicz, Pawel

    2010-01-01

    We describe a duality for quantale-enriched categories that extends the Lawson duality for continuous dcpos: for any saturated class J of modules that commute with certain weighted limits, and under an appropriate choice of morphisms, the category of J-cocomplete and J-continuous quantale-enriched categories is self-dual.

  5. Cultural Heritage Content Re-Use: An Aggregators's Point of View

    Science.gov (United States)

    Gavrilis, D.; Ioannides, M.; Theofanous, E.

    2015-08-01

    This paper introduces a use case of re-using aggregated and enriched metadata for the tourism creative industry. The MORe aggregation and enrichment framework is presented along with an example for enriching cultural heritage objects harvested from a number of Omeka repositories. The enriched content is then published both to the EU Digital Library Europeana (http://www.europeana.eu) and to an Elastic Search component that feeds a portal aimed at providing tourists with interesting information.

  6. Uranium enrichment capacity: public versus private ownership

    International Nuclear Information System (INIS)

    Continual growth of conventional nuclear capacity requires an assured supply of enriched uranium and, hence, potential expansion of domestic uranium enrichment capacity. The question of ownership of new enrichment capacity, i.e., public or private, entails not only the social-opportunity costs of alternative investments but also technical parameters of uranium utilization and advanced reactor development. Inclusion of risk preferences in both the public and private sectors produces interesting results in terms of optimal investment strategies with respect to choice of technology and scale of investment. Utilization of a nuclear fuel cycle requirements process model allows explicit specification of production technology. Integration of process model output with a least-cost investment model permits flexibility in parametric analysis. Results indicate minimum incentive for Government subsidy of a private enrichment sector through 2000 given moderate to low nuclear growth assumptions. The long-run scenario, to 2020, exhibits potentially greater incentives for private enrichment investment

  7. Stable isotope inventory requirements and enrichment capabilities

    International Nuclear Information System (INIS)

    The electromagnetic isotope enrichment program established in 1945 has since then continued to provide enriched stable, actinide, and selected radioactive isotopes. These unique materials used in research and medicine and for industrial applications are made available throughout the world by direct sales and/or on a loan basis. In recent years, the primary effort of the program has been directed toward providing enriched stable isotopes necessary to replenish the sales inventory. This document presents a summary of the stable isotope sales requirements and the capabilities of the electromagnetic isotope separators for providing the quantity and quality of enriched products to meet those needs. Special enrichment and actinide separations or Research Materials Collection (loan program) needs are not addressed

  8. Enriching an effect calculus with linear types

    DEFF Research Database (Denmark)

    Egger, Jeff; Møgelberg, Rasmus Ejlers; Simpson, Alex

    2009-01-01

    We define an ``enriched effect calculus'' by conservatively extending  a type theory for computational effects with primitives from linear logic. By doing so, we obtain a generalisation of linear type theory, intended as a formalism for expressing linear aspects of effects. As a worked example, we...... formulate  linearly-used continuations in the enriched effect calculus. These are captured by a fundamental translation of the enriched effect calculus into itself, which extends existing call-by-value and call-by-name linearly-used CPS translations. We show that our translation is involutive. Full...... completeness results for the various linearly-used CPS translations  follow. Our main results, the conservativity of enriching the effect calculus with linear primitives, and the involution property of the fundamental translation, are proved using a category-theoretic semantics for the enriched effect calculus...

  9. Current perspective of the uranium enrichment market

    International Nuclear Information System (INIS)

    Over the past several years, developments in the uranium enrichment market have required the Department of Energy (DOE) to make a number of changes in the U.S. enrichment enterprise. These changes have been made to allow DOE to conduct our enrichment business so as to be more responsive to changing market forces. Needless to say, some of these changes have been difficult, but they have been necessary if they are to conduct a healthy and competitive uranium enrichment business in the United States. This paper discusses several topics, including: The Uranium Enrichment Market, Utility Services (US) Contracts, Reduced Prices, Incentive Pricing, Better Customer Services, and Advanced Technology. In addition to these topics, information is provided on the recent court action regarding the US Contracts and the viability finding on the uranium mining industry

  10. Enrichment of Acinetobacter spp. from food samples.

    Science.gov (United States)

    Carvalheira, Ana; Ferreira, Vânia; Silva, Joana; Teixeira, Paula

    2016-05-01

    Relatively little is known about the role of foods in the chain of transmission of acinetobacters and the occurrence of different Acinetobacter spp. in foods. Currently, there is no standard procedure to recover acinetobacters from food in order to gain insight into the food-related ecology and epidemiology of acinetobacters. This study aimed to assess whether enrichment in Dijkshoorn enrichment medium followed by plating in CHROMagar™ Acinetobacter medium is a useful method for the isolation of Acinetobacter spp. from foods. Recovery of six Acinetobacter species from food spiked with these organisms was compared for two selective enrichment media (Baumann's enrichment and Dijkshoorn's enrichment). Significantly (p analysis as belonging to the species Acinetobacter johnsonii, Acinetobacter calcoaceticus, Acinetobacter guillouiae and Acinetobacter gandensis. It was not possible to identify the species level of one strain which may suggests that it represents a distinct species. PMID:26742623

  11. Culturing Protozoa.

    Science.gov (United States)

    Stevenson, Paul

    1980-01-01

    Compares various nutrient media, growth conditions, and stock solutions used in culturing protozoa. A hay infusion in Chalkey's solution maintained at a stable temperature is recommended for producing the most dense and diverse cultures. (WB)

  12. Gastric culture

    Science.gov (United States)

    Gastric culture is a test to check a child's stomach contents for the bacteria that cause tuberculosis (TB). ... is placed in a special dish called a culture medium and watched for the growth of bacteria.

  13. Throat Culture

    Science.gov (United States)

    ... limited. Home Visit Global Sites Search Help? Throat Culture Share this page: Was this page helpful? Collecting | ... treatment | Getting results | see BLOOD SAMPLE Collecting A culture is a test that is often used to ...

  14. Priming tissue cultured propagules

    International Nuclear Information System (INIS)

    Priming of in vitro propagules refers to the manipulation of the growing environment, prior to and upon transplanting, and is an integral part of tissue culture propagation. Tissue-cultured propagules are produced under controlled environment. Such plantlets have small juvenile leaves with reduced photosynthetic capacity, and malfunctioning stomata. Priming for rooting, shooting, and improved photosynthesis can be achieved with growth regulators and simple adjustment to the growing conditions that affect the post-transplanting performance of the propagules. Vented closures with microbial filters have been used to facilitate gas exchange to reduce ethylene build-up that stunts plant growth, reduces leaf-size, and causes leaf drop in tissue culture containers. Plantlets produced under photoautotrophic culture systems on media with or without sucrose but CO2-enrichment, increased light intensity, good gas exchange and reduced humidity are more vigorous, have larger root- systems, and are less susceptible to microbial contamination. Plants adapted gradually to the ex-vitro environment have improved survival upon transfer to soil. Plants in their natural environment are colonized with many bacteria, fungi, and mycorrhizae. In-vitro or ex-vitro biopriming of micropropagated plants with such organisms can improve plant performance under stress environments, and consequently enhances yield. (author)

  15. Cultural Neuroscience

    OpenAIRE

    Ames, Daniel L.; Fiske, Susan T

    2010-01-01

    Cultural neuroscience issues from the apparently incompatible combination of neuroscience and cultural psychology. A brief literature sampling suggests, instead, several preliminary topics that demonstrate proof of possibilities: cultural differences in both lower-level processes (e.g. perception, number representation) and higher-order processes (e.g. inferring others’ emotions, contemplating the self) are beginning to shed new light on both culture and cognition. Candidates for future cultu...

  16. Safety culture

    International Nuclear Information System (INIS)

    Safety culture has become a topic of increasing interest for industry and regulators as issues are raised on safety problems around the world. The keys to safety culture are organizational effectiveness, effective communications, organizational learning, and a culture that encourages the identification and resolution of safety issues. The necessity of a strong safety culture places an onus on all of us to continually question whether the safety measures already in place are sufficient, and are being applied. (author)

  17. Nitrogen-removal efficiency of a novel aerobic denitrifying bacterium, Pseudomonas stutzeri strain ZF31, isolated from a drinking-water reservoir.

    Science.gov (United States)

    Huang, Tinglin; Guo, Lin; Zhang, Haihan; Su, Junfeng; Wen, Gang; Zhang, Kai

    2015-11-01

    An aerobic denitrifier, identified as Pseudomonas stutzeri strain ZF31, was isolated from the Zhoucun drinking-water reservoir. Strain ZF31 removed 97% of nitrate nitrogen after 16h, without nitrite accumulation. Sequence amplification indicated the presence of the denitrification genes napA, nirS, norB, and nosZ. Nitrogen balance analysis revealed that approximately 75% of the initial nitrogen was removed as gas products. Response surface methodology (RSM) experiments showed that maximum removal of total nitrogen (TN) occurred at pH 8.23, a C/N ratio of 6.68, temperature of 27.72°C, and with shaking at 54.15rpm. The TN removal rate at low C/N ratio (i.e., 3) and low temperature (i.e., 10°C) was 73.30% and 60.08%, respectively. These results suggest that strain ZF31 has potential applications for the bioremediation of slightly polluted drinking-water reservoirs. PMID:26241840

  18. Profile of World Uranium Enrichment Programs-2009

    International Nuclear Information System (INIS)

    It is generally agreed that the most difficult step in building a nuclear weapon is acquiring fissile material, either plutonium or highly enriched uranium (HEU). Plutonium is produced in a nuclear reactor, whereas HEU is produced using a uranium enrichment process. Enrichment is also an important step in the civil nuclear fuel cycle, in producing low enriched uranium (LEU) for use as fuel for nuclear reactors to generate electricity. However, the same equipment used to produce LEU for nuclear reactor fuel can also be used to produce HEU for weapons. Safeguards at an enrichment plant are the array of assurances and verification techniques that ensure uranium is not diverted or enriched to HEU. There are several techniques for enriching uranium. The two most prevalent are gaseous diffusion, which uses older technology and requires a lot of energy, and gas centrifuge separation, which uses more advanced technology and is more energy efficient. Gaseous diffusion plants (GDPs) provide about 40% of current world enrichment capacity but are being phased out as newer gas centrifuge enrichment plants (GCEPs) are constructed. Estimates of current and future enrichment capacity are always approximate, due to the constant upgrades, expansions, and shutdowns occurring at enrichment plants, largely determined by economic interests. Currently, the world enrichment capacity is approximately 56 million kilogram separative work units (SWU) per year, with 22.5 million in gaseous diffusion and more than 33 million in gas centrifuge plants. Another 34 million SWU/year of capacity is under construction or planned for the near future, almost entirely using gas centrifuge separation. Other less-efficient techniques have also been used in the past, including electromagnetic and aerodynamic separations, but these are considered obsolete, at least from a commercial perspective. Laser isotope separation shows promise as a possible enrichment technique of the future but has yet to be demonstrated commercially. In the early 1980s, six countries developing gas centrifuge technology (United States, United Kingdom, Germany, the Netherlands, Japan, and Australia) along with the International Atomic Energy Agency and the European Atomic Energy Community began developing effective safeguards techniques for GCEPs. This effort was known as the Hexapartite Safeguards Project (HSP). The HSP had the goal of maximizing safeguards effectiveness while minimizing the cost to the operator and inspectorate, and adopted several recommendations, such as the acceptance of limited-frequency unannounced access inspections in cascade halls, and the use of nondestructive assay measurements and tamper-indicating seals. While only the HSP participants initially committed to implementing all the measures of the approach, it has been used as a model for the safeguards applied to GCEPs in additional states. Uranium enrichment capacity has continued to expand on all fronts in the last few years. GCEP capacity is expanding in anticipation of the eventual shutdown of the less-efficient GDPs, the termination of the U.S.-Russia HEU blend-down program slated for 2013, and the possible resurgence of nuclear reactor construction as part of an expected 'Nuclear Renaissance'. Overall, a clear trend in the world profile of uranium enrichment plant operation is the continued movement towards multinational projects driven by commercial and economic interests. Along this vein, the safeguards community is continuing to develop new safeguards techniques and technologies that are not overly burdensome to enrichment plant operators while delivering more effective and efficient results. This report provides a snapshot overview of world enrichment capacity in 2009, including profiles of the uranium enrichment programs of individual states. It is a revision of a 2007 report on the same topic; significant changes in world enrichment programs between the previous and current reports are emphasized. It is based entirely on open-source information, which is dependent on published sources and may theref

  19. CULTURAL VALUES

    OpenAIRE

    Harun, Sudarmin,Dr.S.Arts.SS.M.Hum

    2012-01-01

    This study aimed at finding and elaborating: (1) the cultural symbols, their kinds, their morphemic, literal, and idiomatic meanings, applied in BTS; (2) the aspect of values and their significant meanings, reflected by the cultural symbols in BTS; (3) The significant meanings and the aims of cultural symbols used by Buginese community, which are still relevant in marriage, inauguration, and political contexts.

  20. Italian activities in uranium enrichment

    International Nuclear Information System (INIS)

    The paper describes Italian activities in uranium enrichment, which have mainly developed along the lines of the two classical processes: gaseous diffusion and centrifuges. Research, development and industrial activities play different roles in the two methods, and a special working group, GIAU, was established by CNEN to help co-ordinate this activity. In the field of gaseous diffusion, R and D effort was, from the start of the programme in 1968, mainly devoted to barriers and compressors, with the object of fully understanding the process and of demonstrating that it was capable of overcoming the main problems in this technology. Isotope separation of UF6 was demonstrated in 1974 at experimental plant level. Cost-sharing contracts were signed between CNEN and industries to build prototypes and ''first-of-a-kind'' components; small production lines have been set up to evaluate economics and assess production quality. Eurodif is partially associated with the development of this activity. On the industrial level, AGIP Nucleare and CNEN were among the promoters of the Eurodif venture from the beginning in 1973 and now own 25% of the shares. In the field of ultracentrifugation, work is still devoted mainly to R and D on the machines. The separation process was demonstrated in 1973 at laboratory level with a Zippe type centrifuge. Later activities aimed at developing high-capacity machines; different solutions are under close scrutiny. Carbon fibres and multiplerotor machines have been mechanically tested, and the first reference design of a small cascade plant has been completed. In the field of laser separation, after a complete and critical survey of different processes under development in other countries, experimental research work is now being undertaken, and experiments on basic aspects of the process are in progress. (author)

  1. Internet culture

    CERN Document Server

    Porter, David

    2013-01-01

    The internet has recently grown from a fringe cultural phenomenon to a significant site of cultural production and transformation. Internet Culture maps this new domain of language, politics and identity, locating it within the histories of communication and the public sphere. Internet Culture offers a critical interrogation of the sustaining myths of the virtual world and of the implications of the current mass migration onto the electronic frontier. Among the topics discussed in Internet Culture are the virtual spaces and places created by the citizens of the Net and their claims to the hot

  2. Spatial Culture

    DEFF Research Database (Denmark)

    Reeh, Henrik

    2012-01-01

    Spatial Culture – A Humanities Perspective Abstract of introductory essay by Henrik Reeh Secured by alliances between socio-political development and cultural practices, a new field of humanistic studies in spatial culture has developed since the 1990s. To focus on links between urban culture and...... the years 2002 – 2006. The essays published here allow us to subdivide the field of spatial culture into five major domains, summarized in the titles of chapters in the book: ”Perception and Strategies: Architecture”, ”Politics and Poetics: Urban Spaces”, ”Movements and Cityscape: Textuality”, ”Crisis...

  3. Developments in world enrichment supply and economics

    International Nuclear Information System (INIS)

    The paper discusses the supply and demand situation for enriched uranium in the 1990s, how advanced technology can impact the market and the restructuring of the United States uranium enrichment enterprise. In the 1990s, utilities are expected to spend about US $2.5 billion per year for enrichment services. (One billion = 109). Enrichment demand in the world outside centrally planned economies area should increase through the 1990s, from 25 million separate work units today to over 30 million by 2000. However, there should be a plentiful supply of enriched uranium at reasonable prices in the 1990s. It appears that the world enrichment market will become even more competitive, with additional suppliers entering the market. The United States of America and other countries are actively developing advanced technology, since it promises lower prices. There is a strong incentive to be the first to develop and deploy advanced technology. The USA is in the process of restructuring its enrichment enterprise to give it added stability and flexibility. (author). 8 figs

  4. DOE enrichment plants-safeguards means business

    International Nuclear Information System (INIS)

    The Portsmouth Gaseous Diffusion Plant, owned by the US Department of Energy (DOE) and operated by Martin Marietta Energy Systems, Inc., is a full service enrichment plant. Its long enriching cascade can process uranium hexafluoride (UF6) feeds at almost any 235U level and can produce UF6 over the complete spectrum from depleted to very highly enriched uranium. The DOE uranium enrichment program is a government-owned enterprise operating as a business. The operating concerns of the DOE uranium enrichment plants and their safeguards programs have evolved together over the past three decades, and that evolution will likely continue. As the risk associated with possession, processing, and shipment of strategic nuclear material increased, the protection and control of it increased; as the value of the product grew with time, better ways were found to measure and conserve it. In each of these areas, safeguards objectives and the business requirements of the plant are complementary, and the progress made in one area has been reflected by progress in the other. The plant's material control and accountability program has become crucial to such business requirements as quantifying the enriched uranium (separative work units) produced in each monthly period and convincing financial auditors that the multibillion dollar enriched uranium assets located at the Portsmouth plant are properly stated

  5. Isotopically enriched additions in nuclear fuel

    International Nuclear Information System (INIS)

    In the report one of the main problems of nuclear energetics - preparation of isotopically enriched additions to nuclear fuel - is in consideration. At some NPP new types of fuels with integrated burning out absorber on the base of gadolinium and erbium are utilized. For compensation of the excessive reactivity neutron absorbers in the form of burning out additions are situated in fuel pellets directly. Gadolinium, erbium, hafnium, boron and dysprosium ca be used as burning out additions. The key problem in production of fuel with isotopically enriched additions is economically expedient method of enrichment

  6. Metal enrichment of the CGM through outflows

    Science.gov (United States)

    Christensen, Charlotte

    2016-01-01

    Galactic outflows enrich the circumgalactic medium through the redistribution of metals from the disks of galaxies. We examine the history of this enrichment by analyzing the outflows of twenty high-resolution simulated galaxies spanning two and a half orders of magnitude in halo mass. These simulations match many observed trends, including the mass-metallicity relation. By tracking particles in the simulations, we follow the removal and reaccretion of metals between redshift 3.5 and 0. We also determine the enrichment of the outflowing gas compared to the local interstellar media. Finally we compare the redshift zero metal census to observed values.

  7. The US Enrichment Corp.. Looking towards privatisation

    International Nuclear Information System (INIS)

    The United States Enrichment Corporation (USEC) was launched in 1993 with the intention of bringing private sector disciplines into the US enrichment industry. It is charged with operating as a business enterprise on a profitable and efficient basis, with maximizing the long term value of the Corporation to the Treasury and taxpayer, and with maintaining a reliable and economic source of enriched uranium. Though acting like a commercial business, it remains for the moment in US government ownership. The directors have an obligation, however, to recommend to the government in 1995 if, how and when the Corporation should be privatized. (UK)

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

    OpenAIRE

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

    2012-01-01

    The short-chain, non-methane hydrocarbons propane and butane can contribute significantly to the carbon and sulfur cycles in marine environments affected by oil or natural gas seepage. In the present study, we enriched and identified novel propane and butane-degrading sulfate reducers from marine oil and gas cold seeps in the Gulf of Mexico and Hydrate Ridge. The enrichment cultures obtained were able to degrade simultaneously propane and butane, but not other gaseous alkanes. They were cold-...

  9. Anaerobic degradation of benzene by enriched consortia with humic acids as terminal electron acceptors

    Energy Technology Data Exchange (ETDEWEB)

    Cervantes, Francisco J., E-mail: fjcervantes@ipicyt.edu.mx [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico); Mancilla, Ana Rosa; Toro, E. Emilia Rios-del [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico); Alpuche-Solis, Angel G.; Montoya-Lorenzana, Lilia [Division de Biologia Molecular, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico)

    2011-11-15

    Highlights: {yields} Enriched consortia were able to couple the anaerobic degradation of benzene to the reduction of humic acids. {yields} Electron-equivalents derived from anaerobic benzene oxidation were highly recovered as reduced humic acids. {yields} Several species from classes {beta}-, {delta}- and {gamma}-Proteobacteria were enriched during the anaerobic degradation of benzene. - Abstract: The anaerobic degradation of benzene coupled to the reduction of humic acids (HA) was demonstrated in two enriched consortia. Both inocula were able to oxidize benzene under strict anaerobic conditions when the humic model compound, anthraquinone-2,6-disulfonate (AQDS), was supplied as terminal electron acceptor. An enrichment culture originated from a contaminated soil was also able to oxidize benzene linked to the reduction of highly purified soil humic acids (HPSHA). In HPSHA-amended cultures, 9.3 {mu}M of benzene were degraded, which corresponds to 279 {+-} 27 micro-electron equivalents ({mu}Eq) L{sup -1}, linked to the reduction of 619 {+-} 81 {mu}Eq L{sup -1} of HPSHA. Neither anaerobic benzene oxidation nor reduction of HPSHA occurred in sterilized controls. Anaerobic benzene oxidation did not occur in soil incubations lacking HPSHA. Furthermore, negligible reduction of HPSHA occurred in the absence of benzene. The enrichment culture derived from this soil was dominated by two {gamma}-Proteobacteria phylotypes. A benzene-degrading AQDS-reducing enrichment originated from a sediment sample showed the prevalence of different species from classes {beta}-, {delta}- and {gamma}-Proteobacteria. The present study provides clear quantitative demonstration of anaerobic degradation of benzene coupled to the reduction of HA.

  10. Enrichment of Mouse Spermatogonial Stem Cells by the Stem Cell Dye CDy1.

    Science.gov (United States)

    Kanatsu-Shinohara, Mito; Morimoto, Hiroko; Shinohara, Takashi

    2016-12-01

    Spermatogonial stem cells (SSCs) comprise a small population of germ cells with self-renewal potential. Previous studies have shown that SSCs share several common features with stem cells in other self-renewing tissues, including surface markers and proliferative machinery. However, studies of SSCs are severely handicapped by the small number of SSCs and the lack of SSC-specific markers. In the present study, we examined the utility of CDy1 and Rh123, both of which are used for the collection of stem cells in several self-renewing tissues. CDy1 stained germline stem (GS) cells, cultured spermatogonia enriched for SSC activity, after in vitro incubation without exerting toxic effects. Unlike previously reported stem cell-specific dyes, CDy1 was also useful for enrichment of SSCs in both GS cell culture and mature adult testes. Spermatogonial transplantation showed that ∼1 in 66.7 cells exhibited SSC activity after CDH1-based magnetic cell selection and CDy1 staining. In contrast, although Rh123 was previously used successfully to collect SSCs from cryptorchid testes, it was not possible to recover SSCs from both GS cell cultures and wild-type testes. Thus, CDy1 staining will provide a useful strategy for the enrichment of SSCs and may be used in conjunction with other reagents for the enrichment of SSCs. PMID:26607720

  11. Enrichment and isolation of Flavobacterium strains with tolerance to high concentrations of cesium ion.

    Science.gov (United States)

    Kato, Souichiro; Goya, Eri; Tanaka, Michiko; Kitagawa, Wataru; Kikuchi, Yoshitomo; Asano, Kozo; Kamagata, Yoichi

    2016-01-01

    Interest in the interaction of microorganisms with cesium ions (Cs(+)) has arisen, especially in terms of their potent ability for radiocesium bioaccumulation and their important roles in biogeochemical cycling. Although high concentrations of Cs(+) display toxic effects on microorganisms, there have been only limited reports for Cs(+)-tolerant microorganisms. Here we report enrichment and isolation of Cs(+)-tolerant microorganisms from soil microbiota. Microbial community analysis revealed that bacteria within the phylum Bacteroidetes, especially Flavobacterium spp., dominated in enrichment cultures in the medium supplemented with 50 or 200?mM Cs(+), while Gammaproteobacteria was dominant in the control enrichment cultures (in the presence of 50 and 200?mM K(+) instead of Cs(+)). The dominant Flavobacterium sp. was successfully isolated from the enrichment culture and was closely related to Flavobacterium chungbukense with 99.5% identity. Growth experiments clearly demonstrated that the isolate has significantly higher tolerance to Cs(+) compared to its close relatives, suggesting the Cs(+)-tolerance is a specific trait of this strain, but not a universal trait in the genus Flavobacterium. Measurement of intracellular K(+) and Cs(+) concentrations of the Cs(+)-tolerant isolate and its close relatives suggested that the ability to maintain low intracellular Cs(+) concentration confers the tolerance against high concentrations of external Cs(+). PMID:26883718

  12. Development of a bacterial cell enrichment method and its application to the community analysis in soybean stems.

    Science.gov (United States)

    Ikeda, Seishi; Kaneko, Takakazu; Okubo, Takashi; Rallos, Lynn E E; Eda, Shima; Mitsui, Hisayuki; Sato, Shusei; Nakamura, Yasukazu; Tabata, Satoshi; Minamisawa, Kiwamu

    2009-11-01

    A method was developed for enriching bacterial cells from soybean stems which was recalcitrant for a culture-independent analysis of bacterial community due to the interference with plant DNA. Stem homogenates were fractionated by a series of differential centrifugations followed by a Nycodenz density gradient centrifugation. The efficiency of bacterial cell enrichment was assessed by ribosomal intergenic spacer analysis (RISA). The intensity and the number of bacterial amplicons of RISA were markedly increased in the DNA extracted from the enriched bacterial cells compared to that in the DNA directly extracted from soybean stems. The phylogenetic diversity of the enriched bacterial cells was evaluated by analyzing a clone library of 16S rRNA gene in comparison with those of the culturable fractions of the enriched and non-enriched stem-associated bacteria, endophytic bacteria, and epiphytic bacteria. The results indicated that the method was able to enrich both endophytic and epiphytic bacteria from soybean stems, and was useful to assess the bacterial diversity based on a 16S rRNA gene clone library. When the sequence data from all clones (1,332 sequences) were combined, 72 operational taxonomic units were affiliated with Proteobacteria (Alpha-, Beta-, and Gammaproteobacteria), Actinobacteria, Firmicutes, and Bacteroidetes, which also provided the most comprehensive set of data on the bacterial diversity in the aerial parts of soybeans. PMID:19662454

  13. A Guide to Job Enrichment and Redesign.

    Science.gov (United States)

    Cunningham, J. Barton; Eberle, Ted

    1990-01-01

    Describes job design alternatives--job enrichment, the job characteristics model, Japanese style management, and quality-of-worklife approaches. Focuses on the problems that human resources professionals may encounter when attempting to implement these approaches. (Author/JOW)

  14. Safety aspects of gas centrifuge enrichment plants

    International Nuclear Information System (INIS)

    Uranium enrichment by gas centrifuge is a commercially proven, viable technology. Gas centrifuge enrichment plant operations pose hazards that are also found in other industries as well as unique hazards as a result of processing and handling uranium hexafluoride and the handling of enriched uranium. Hazards also found in other industries included those posed by the use of high-speed rotating equipment and equipment handling by use of heavy-duty cranes. Hazards from high-speed rotating equipment are associated with the operation of the gas centrifuges themselves and with the operation of the uranium hexafluoride compressors in the tail withdrawal system. These and related hazards are discussed. It is included that commercial gas centrifuge enrichment plants have been designed to operate safely

  15. Stable Isotope Enrichment Capabilities at ORNL

    Energy Technology Data Exchange (ETDEWEB)

    Egle, Brian [ORNL; Aaron, W Scott [ORNL; Hart, Kevin J [ORNL

    2013-01-01

    The Oak Ridge National Laboratory (ORNL) and the US Department of Energy Nuclear Physics Program have built a high-resolution Electromagnetic Isotope Separator (EMIS) as a prototype for reestablishing a US based enrichment capability for stable isotopes. ORNL has over 60 years of experience providing enriched stable isotopes and related technical services to the international accelerator target community, as well as medical, research, industrial, national security, and other communities. ORNL is investigating the combined use of electromagnetic and gas centrifuge isotope separation technologies to provide research quantities (milligram to several kilograms) of enriched stable isotopes. In preparation for implementing a larger scale production facility, a 10 mA high-resolution EMIS prototype has been built and tested. Initial testing of the device has simultaneously collected greater than 98% enriched samples of all the molybdenum isotopes from natural abundance feedstock.

  16. Management's Ecstasy and Disparity Over Job Enrichment

    Science.gov (United States)

    King, Albert S.

    1976-01-01

    A case study analyzing job enrichment schemes and manager expectations of increased productivity is presented. It was found that it was the managers' expectations of increased productivity, not the reorganization of work, that led to higher productivity. (EC)

  17. Job Enrichment: How to Avoid the Pitfalls

    Science.gov (United States)

    Tregoe, Benjamin B., Jr.

    1974-01-01

    While many job enrichment programs fail, a program called Analytical Trouble Shooting has been successful in training people to increase their problem-solving capabilities and to communicate readily with persons in other areas and on different levels. (AG)

  18. The role of work-family enrichment in work-life balance & career success

    OpenAIRE

    Shah, Shalaka Sharad

    2014-01-01

    The issue of work-life balance is becoming increasingly important for employers and employees globally. The clearer becomes our understanding about this issue; the better it will be for an effective and positive integration of these dynamic domains of our lives. Work-family enrichment is a positive way of integrating work and family and it helps to achieve work-life balance. In this Indo-German study, work-life balance, work-family enrichment, work-family culture and career success are analys...

  19. Principles and techniques of uranium enrichment

    International Nuclear Information System (INIS)

    The main separation processes already used industrially or likely to be used before the end of century (gas diffusion, ultracentrifugation, laser, the nozzle process, a process developed in South Africa) are presented. Some data on the costs of the enrichment are clarified. The main characteristics of the enrichment market in which the Eurodif plant is called upon, on the expiration of five years, to take a foremost place are reported

  20. Uranium enrichment activities: the SILVA project

    International Nuclear Information System (INIS)

    In the general frame of a long term R and D uranium enrichment approach, the French laser isotope separation program (SILVA) is presented including fundamentals of the process, an overview of its organization and activities. The main areas of basic research, subsystems assessment, enrichment demonstrations and plant design are described. The general schedule leading to a future commercial plant is outlined. 11 refs., 7 figs