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Sample records for aerobic co-oxidizing thermophile

  1. Aerobic Thermophilic Composting of Municipal Solid Waste

    Directory of Open Access Journals (Sweden)

    D V Wadkar

    2013-03-01

    Full Text Available Composting is a natural process that turns organic material into a dark rich substance called compost. Aerobic Composting is the creation of compost that depends on bacteria that thrive in an oxygen rich environment. Aerobic bacteria manage the chemical process by converting the inputs (i.e. air, water and carbon and nitrogen rich materials into heat, carbon dioxide and ammonium. The ammonium is further converted by bacteria into plant nourishing nitrites and nitrates through the process of nitrification. Thermophilic Composting is breaking down biological waste with thermophilic (heat loving bacteria. A cylindrical reactor was made. Organic wasteincluded dry vegetable waste collected from MSW ramp, Koregaon park, Pune. The characteristics of compost like pH, moisture content, temperature, C/N ratio and volume reduction were studied for the period of maturation (42days. It can be concluded that the values are within the desired limits and compost is suitable for ornamental plants. The setup of reactor is affordable and thus the compost obtained is effective and economical.

  2. Kinetic comparisons of mesophilic and thermophilic aerobic biomass

    NARCIS (Netherlands)

    Vogelaar, J.C.T.; Klapwijk, A.; Temmink, H.; Lier, van J.B.

    2003-01-01

    Kinetic parameters describing growth and decay of mesophilic (30degreesC) and thermophilic (55degreesC) aerobic biomass were determined in continuous and batch experiments by using oxygen uptake rate measurements
    Kinetic parameters describing growth and decay of mesophilic (30degreesC) and therm

  3. Solid-Phase Thermophilic Aerobic Reactor (STAR) Processing of Fecal, Food, and Plant Residues

    OpenAIRE

    2006-01-01

    A description of the Solid Waste Resource Recovery ALS-NSCORT projects: Solid Phase Thermophilic Aerobic Reactor (STAR), Nitrogen Cycling in Advanced Life Support Systems, and Plant-based Anaerobic-Aerobic Bioreactor Linked Operation (PAABLO). 26 pages.

  4. Habitat, applications and genomics of the aerobic, thermophilic genus Geobacillus.

    Science.gov (United States)

    McMullan, G; Christie, J M; Rahman, T J; Banat, I M; Ternan, N G; Marchant, R

    2004-04-01

    Thermophilic bacteria belonging to Bacillus genetic group 5 have been reclassified as being members of Geobacillus gen. nov., with G. stearothermophilus as the type strain. Geobacillus species, literally meaning earth or soil Bacillus, are widely distributed and readily isolated from natural and man-made thermophilic biotopes. Work within our group has however shown that an abundance of genetically distinct Geobacillus isolates can be obtained from temperate Irish soils. As with many thermophiles there is considerable interest in potential industrial application of these bacteria and their gene products. This review describes two novel applications for Geobacillus isolates, firstly in the metabolism of the herbicide glyphosate and secondly in the metabolism of quorum-sensing signal molecules from Gram-negative bacteria. Finally the current state of the art is described for Bacillus genomics, with details given of three independent genome-sequencing projects of Geobacillus isolates.

  5. Thermophilic aerobic post treatment of anaerobically pretreated paper process water

    NARCIS (Netherlands)

    Vogelaar, J.C.T.

    2002-01-01

    Thermophilic waste- or process water treatment increases in importance as industries shift from end-of-pipe treatment towards integrated process water treatment. The need for process water treatment becomes evident as the levels of pollutants in industrial water circuits need to be co

  6. Space agriculture for habitation on Mars with hyper-thermophilic aerobic composting bacteria

    Science.gov (United States)

    Kanazawa, S.; Ishikawa, Y.; Tomita-Yokotani, K.; Hashimoto, H.; Kitaya, Y.; Yamashita, M.; Nagatomo, M.; Oshima, T.; Wada, H.; Space Agriculture Task Force, J.

    Manned Mars exploration requires recycle of materials to support human life A conceptual design is developed for space agriculture which is driven by the biologically regenerative function Hyper-thermophilic aerobic composting bacterial ecology is the core of materials recycling system to process human metabolic waste and inedible biomass and convert them to fertilizer for plants cultivation A photosynthetic reaction of plants will be driven by solar energy Water will be recycled by cultivation of plants and passing it through plant bodies Sub-surface water and atmospheric carbon dioxide are the natural resource available on Mars and these resources will be converted to oxygen and foods We envision that the agricultural system will be scaled up by importing materials from Martian environment Excess oxygen will be obtained from growing trees for structural and other components Minor elements including N P K and other traces will be introduced as fertilizers or nutrients into the agricultural materials circulation Nitrogen will be collected from Martian atmosphere We will assess biological fixation of nitrogen using micro-organisms responsible in Earth biosphere Hyper-thermophilic aerobic bacterial ecology is effective to convert waste materials into useful forms to plants This microbial technology has been well established on ground for processing sewage and waste materials For instance the hyper-thermophilic bacterial system is applied to a composting machine in a size of a trash box in home kitchen Since such a home electronics

  7. Auto heated Thermophilic Aerobic Digestion of sewage sludge; Digestion aerobia termofila autosostenida de lodos urbanos

    Energy Technology Data Exchange (ETDEWEB)

    Garcia de las Heras, J. L.; Gutierrez, I.

    2002-07-01

    Auto heated Thermophilic Aerobic Digestion (ATAD) is one of the most promising technologies for applying the digested sludge to soil amendment. The system was studied in the 60's and developed mostly in Europe since the 70's. The full-scale facilities improvement ran in parallel to the scientific and legislative worry about the presence of pathogenic organisms both in the raw and the digested sewage sludge. ATAD is usually a two stage aerobic process working in the thermophilic temperature range (40 to 80 degree centigree) without any external heat source; the heat produced by the biochemical exergonic reactions during the aerobic degradation of the organic sludge holds the desired temperature values. A comparison of this system with the existing anaerobic stabilisation processes shows as main advantages a high hygienization capacity, small reactor volume for the same organic loading, is resistant to overloading and temperature shocks, is easily manageable, and is economically feasible for small.medium size populations. This process is specially suitable to fulfill the law requirements imposed by the most demanding countries regarding the application of treated sewage sludge to soil improvement. (Author) 19 refs.

  8. Space agriculture for habitation on Mars with hyper-thermophilic aerobic composting bacteria

    Science.gov (United States)

    Space Agriculture Task Force; Ishikawa, Y.; Tomita-Yokotani, K.; Hashimoto, H.; Kitaya, Y.; Yamashita, M.; Nagatomo, M.; Oshima, T.; Wada, H.

    Manned Mars exploration, especially for extended periods of time, will require recycle of materials to support human life. Here, a conceptual design is developed for a Martian agricultural system driven by biologically regenerative functions. One of the core biotechnologies function is the use of hyper-thermophilic aerobic composting bacterial ecology. These thermophilic bacteria can play an important role in increasing the effectiveness of the processing of human metabolic waste and inedible biomass and of converting them to fertilizer for the cultivation of plants. This microbial technology has been already well established for the purpose of processing sewage and waste materials for small local communities in Japan. One of the characteristics of the technology is that the metabolic heat release that occurs during bacterial fermentation raises the processing temperature sufficiently high at 80 100 °C to support hyper-thermophilic bacteria. Such a hyper-thermophilic system is found to have great capability of decomposing wastes including even their normally recalcitrant components, in a reasonably short period of time and of providing a better quality of fertilizer as an end-product. High quality compost has been shown to be a key element in creating a healthy regenerative food production system. In ground-based studies, the soil microbial ecology after the addition of high quality compost was shown to improve plant growth and promote a healthy symbiosis of arbuscular mycorrhizal fungi. Another advantage of such high processing temperature is the ability to sterilize the pathogenic organisms through the fermentation process and thus to secure the hygienic safety of the system. Plant cultivation is one of the other major systems. It should fully utilize solar energy received on the Martian surface for supplying energy for photosynthesis. Subsurface water and atmospheric carbon dioxide mined on Mars should be also used in the plant cultivation system. Oxygen and

  9. Aerobic moving bed biofilm reactor treating thermomechanical pulping whitewater under thermophilic conditions.

    Science.gov (United States)

    Jahren, Sigrun J; Rintala, Jukka A; Odegaard, Hallvard

    2002-02-01

    The continuously operated laboratory scale Kaldnes moving bed biofilm reactor (MBBR) was used for thermophilic (55 degrees C) aerobic treatment of TMP whitewater. In the MBBR, the biomass is grown on carrier elements that move along with the water in the reactor. Inoculation with mesophilic activated sludge gave 60-65% SCOD removal from the first day onwards. During the 107 days of experiment, the 60-65% SCOD removals were achieved at organic loading rates of 2.5-3.5 kg SCODm(-3) d(-1), the highest loading rates applied during the run and HRT of 13-22h. Carbohydrates, which contributed to 50-60% of the influent SCOD. were removed by 90-95%, while less than 15% of the lignin-like material (30-35% of SCODin) was removed. The sludge yield was 0.23g VSSg SCOD(-1)removed. The results show that the aerobic biofilm process can be successfully operated under thermophilic conditions. PMID:11848344

  10. Bacterial community analysis of swine manure treated with autothermal thermophilic aerobic digestion.

    Science.gov (United States)

    Han, Il; Congeevaram, Shankar; Ki, Dong-Won; Oh, Byoung-Taek; Park, Joonhong

    2011-02-01

    Due to the environmental problems associated with disposal of livestock sludge, many stabilization studies emphasizing on the sludge volume reduction were performed. However, little is known about the microbial risk present in sludge and its stabilized products. This study microbiologically explored the effects of anaerobic lagoon fermentation (ALF) and autothermal thermophilic aerobic digestion (ATAD) on pathogen-related risk of raw swine manure by using culture-independent 16S rDNA cloning and sequencing methods. In raw swine manure, clones closely related to pathogens such as Dialister pneumosintes, Erysipelothrix rhusiopathiae, Succinivibrioan dextrinosolvens, and Schineria sp. were detected. Meanwhile, in the mesophilic ALF-treated swine manure, bacterial community clones closely related to pathogens such as Schineria sp. and Succinivibrio dextrinosolvens were still detected. Interestingly, the ATAD treatment resulted in no detection of clones closely related to pathogens in the stabilized thermophilic bacterial community, with the predominance of novel Clostridia class populations. These findings support the superiority of ATAD in selectively reducing potential human and animal pathogens compared to ALF, which is a typical manure stabilization method used in livestock farms. PMID:20922382

  11. Dynamic analysis of a bio filter treating autothermal thermophilic aerobic digestion offgas

    Energy Technology Data Exchange (ETDEWEB)

    Shanchayan, B. [Carleton Univ., Ottawa, ON (Canada). Dept. of Civil and Environmental Engineering; Parker, W. [Waterloo Univ., ON (Canada). Dept. of Civil Engineering; Pride, C. [Ambio Biofiltration, Rockland, ON (Canada)

    2006-05-15

    Biofiltration has become the preferred technology to treat offgases from wastewater treatment facilities because of its low operating cost. However, the underlying principles of biofiltration have only recently begun to be understood. In this study, the dynamic variation in the composition of offgases from a full-scale autothermal thermophilic aerobic digestion (ATAD) was characterized, and the performance of a biofilter treating the offgases was examined. Gas and liquid phase streams in the biofilter were measured to identify the mechanisms responsible for the removal of odorants. ATAD is a sludge process that has been found to emit relatively high quantities of ammonia (NH{sub 3}) and reduced sulfur compounds (RSCs). An existing ATAD and biofilter system at a site in Oregon was used in the study. Gas flows were calculated from air velocities that were measured with a hotwire thermo-anemometer at the biofilter inlet. Sampling was performed on an hourly basis over a 24 hour period. Liquid flows were measured hourly at the biofilter leachate sump inlet. It was observed that the ATAD reactors released NH{sub 3} and RSCs in a cyclic pattern. Gas phase concentrations of NH{sub 3} increased with time and location along the digester sequence. A wet scrubber removed nearly 85 per cent of NH{sub 3} and 60 per cent of H{sub 2}S. The removal efficiencies in the biofilter were more than 99 per cent for hydrogen sulfide and methyl mercaptan, and more than 94 per cent for dimethyl sulfide and dimethyl disulfide. The removal efficiency of each compound demonstrated the effectiveness of the biofilter and wet scrubber combination for the ATAD offgas removal. 24 refs., 5 tabs., 9 figs.

  12. Thermaerobacter litoralis sp. nov., a strictly aerobic and thermophilic bacterium isolated from a coastal hydrothermal field

    DEFF Research Database (Denmark)

    Tanaka, Reiji; Kawaichi, Satoshi; Nishimura, Hiroshi;

    2006-01-01

    A novel thermophilic bacterium, strain KW1T, was isolated from a coastal hydrothermal field on the Satsuma Peninsula, Kagoshima Prefecture, Japan. The variably Gram-stained cells were motile rods with flagella, did not form spores and proliferated at 52-78°C (optimum, 70°C), pH 5-8 (optimum, pH 7...

  13. Evaluation of the removal of indicator bacteria from domestic sludge processed by Autothermal Thermophilic Aerobic Digestion (ATAD).

    Science.gov (United States)

    Piterina, Anna V; Bartlett, John; Pembroke, Tony J

    2010-09-01

    The degradation of sludge solids in an insulated reactor during Autothermal Thermophilic Aerobic Digestion (ATAD) processing results in auto-heating, thermal treatment and total solids reduction, however, the ability to eliminate pathogenic organisms has not been analysed under large scale process conditions. We evaluated the ATAD process over a period of one year in a two stage, full scale Irish ATAD plant established in Killarney and treating mixed primary and secondary sludge, by examining the sludge microbiologically at various stages during and following ATAD processing to determine its ability to eliminate indicator organisms. Salmonella spp. (pathogen) and fecal-coliform (indicator) densities were well below the limits used to validate class A biosolids in the final product. Enteric pathogens present at inlet were deactivated during the ATAD process and were not detected in the final product using both traditional microbial culture and molecular phylogenetic techniques. A high DNase activity was detected in the bulk sludge during the thermophilic digestion stage which may be responsible for the rapid turn over of DNA from lysed cells and the removal of mobile DNA. These results offer assurance for the safe use of ATAD sludge as a soil supplement following processing.

  14. Evaluation of the Removal of Indicator Bacteria from Domestic Sludge Processed by Autothermal Thermophilic Aerobic Digestion (ATAD

    Directory of Open Access Journals (Sweden)

    Tony J. Pembroke

    2010-09-01

    Full Text Available The degradation of sludge solids in an insulated reactor during Autothermal Thermophilic Aerobic Digestion (ATAD processing results in auto-heating, thermal treatment and total solids reduction, however, the ability to eliminate pathogenic organisms has not been analysed under large scale process conditions. We evaluated the ATAD process over a period of one year in a two stage, full scale Irish ATAD plant established in Killarney and treating mixed primary and secondary sludge, by examining the sludge microbiologically at various stages during and following ATAD processing to determine its ability to eliminate indicator organisms. Salmonella spp. (pathogen and fecal-coliform (indicator densities were well below the limits used to validate class A biosolids in the final product. Enteric pathogens present at inlet were deactivated during the ATAD process and were not detected in the final product using both traditional microbial culture and molecular phylogenetic techniques. A high DNase activity was detected in the bulk sludge during the thermophilic digestion stage which may be responsible for the rapid turn over of DNA from lysed cells and the removal of mobile DNA. These results offer assurance for the safe use of ATAD sludge as a soil supplement following processing.

  15. Molecular Analysis of Bacterial Community DNA in Sludge Undergoing Autothermal Thermophilic Aerobic Digestion (ATAD): Pitfalls and Improved Methodology to Enhance Diversity Recovery

    OpenAIRE

    Anna V. Piterina; John Bartlett; Tony Pembroke, J.

    2010-01-01

    Molecular analysis of the bacterial community structure associated with sludge processed by autothermal thermophilic aerobic digestion (ATAD), was performed using a number of extraction and amplification procedures which differed in yield, integrity, ability to amplify extracted templates and specificity in recovering species present. Interference to PCR and qPCR amplification was observed due to chelation, nuclease activity and the presence of thermolabile components derived from the ATAD sl...

  16. Microbial community structure in a thermophilic aerobic digester used as a sludge pretreatment process for the mesophilic anaerobic digestion and the enhancement of methane production.

    Science.gov (United States)

    Jang, Hyun Min; Park, Sang Kyu; Ha, Jeong Hyub; Park, Jong Moon

    2013-10-01

    An effective two-stage sewage sludge digestion process, consisting of thermophilic aerobic digestion (TAD) followed by mesophilic anaerobic digestion (MAD), was developed for efficient sludge reduction and methane production. Using TAD as a biological pretreatment, the total volatile suspended solid reduction (VSSR) and methane production rate (MPR) in the MAD reactor were significantly improved. According to denaturing gradient gel electrophoresis (DGGE) analysis, the results indicated that the dominant bacteria species such as Ureibacillus thermophiles and Bacterium thermus in TAD were major routes for enhancing soluble organic matter. TAD pretreatment using a relatively short SRT of 1 day showed highly increased soluble organic products and positively affected an increment of bacteria populations which performed interrelated microbial metabolisms with methanogenic species in the MAD; consequently, a quantitative real-time PCR indicated greatly increased Methanosarcinales (acetate-utilizing methanogens) in the MAD, resulting in enhanced methane production.

  17. Microbial community structure in a thermophilic aerobic digester used as a sludge pretreatment process for the mesophilic anaerobic digestion and the enhancement of methane production.

    Science.gov (United States)

    Jang, Hyun Min; Park, Sang Kyu; Ha, Jeong Hyub; Park, Jong Moon

    2013-10-01

    An effective two-stage sewage sludge digestion process, consisting of thermophilic aerobic digestion (TAD) followed by mesophilic anaerobic digestion (MAD), was developed for efficient sludge reduction and methane production. Using TAD as a biological pretreatment, the total volatile suspended solid reduction (VSSR) and methane production rate (MPR) in the MAD reactor were significantly improved. According to denaturing gradient gel electrophoresis (DGGE) analysis, the results indicated that the dominant bacteria species such as Ureibacillus thermophiles and Bacterium thermus in TAD were major routes for enhancing soluble organic matter. TAD pretreatment using a relatively short SRT of 1 day showed highly increased soluble organic products and positively affected an increment of bacteria populations which performed interrelated microbial metabolisms with methanogenic species in the MAD; consequently, a quantitative real-time PCR indicated greatly increased Methanosarcinales (acetate-utilizing methanogens) in the MAD, resulting in enhanced methane production. PMID:23419990

  18. Molecular Analysis of Bacterial Community DNA in Sludge Undergoing Autothermal Thermophilic Aerobic Digestion (ATAD: Pitfalls and Improved Methodology to Enhance Diversity Recovery

    Directory of Open Access Journals (Sweden)

    Anna V. Piterina

    2010-03-01

    Full Text Available Molecular analysis of the bacterial community structure associated with sludge processed by autothermal thermophilic aerobic digestion (ATAD, was performed using a number of extraction and amplification procedures which differed in yield, integrity, ability to amplify extracted templates and specificity in recovering species present. Interference to PCR and qPCR amplification was observed due to chelation, nuclease activity and the presence of thermolabile components derived from the ATAD sludge. Addition of selected adjuvant restored the ability to amplify community DNA, derived from the thermophilic sludge, via a number of primer sets of ecological importance and various DNA polymerases. Resolution of community profiles by molecular techniques was also influenced by the ATAD sludge extraction procedure as demonstrated by PCR-DGGE profiling and comparison of taxonomic affiliations of the most predominant members within 16S rRNA gene libraries constructed from ATAD DNA extracted by different methods. Several modifications have been shown to be necessary to optimize the molecular analysis of the ATAD thermal niche which may have general applicability to diversity recovery from similar environments.

  19. Thermolongibacillus altinsuensis gen. nov., sp. nov. and Thermolongibacillus kozakliensis sp. nov., aerobic, thermophilic, long bacilli isolated from hot springs.

    Science.gov (United States)

    Cihan, Arzu Coleri; Koc, Melih; Ozcan, Birgul; Tekin, Nilgun; Cokmus, Cumhur

    2014-01-01

    Two novel endospore-forming, aerobic bacilli, strains E173a(T) and E265(T), were isolated from soil and sediment samples from Kozakli and Altinsu hot springs, Nevsehir (Turkey). Their young cells in the exponential phase of growth were motile, Gram-stain-positive, straight rods, 0.6-1.1×3.0-8.0 µm in size, but they became strikingly long, approximately 0.6-1.2 by 9.0-35.0 µm, after the stationary phase of growth. Cells varied in tests for oxidase, and had a weakly positive reaction for catalase. Both strains could grow between 40 and 70 °C, with optimal growth at 60 °C (E173a(T)) and 55 °C (E265(T)). Growth occurred within the range pH 5.0-11.0 with optimal growth at pH 9.0 (E173a(T)) and pH 8.5 (E265(T)). Strain E173a(T) grew within a salinity range from 0 to1.5 % (w/v) NaCl with optimal growth at 0.5 %, while strain E265(T) grew within the range 0-5.0 % (w/v), with an optimum at 3.0 %. The new isolates differed from each other in some phenotypic and chemotaxonomic characters as well as repetitive extragenic palindromic element PCR (rep-PCR) fingerprints. 16S rRNA gene sequence similarities suggested distant relationships with other members of the family Bacillaceae (60 %), iso-C17 : 0 and C16 : 0] supported the consideration of these isolates as members of a novel genus. Based upon phenotypic, phylogenetic and chemotaxonomic characteristics, it is proposed that new isolates represent a novel genus, Thermolongibacillus gen. nov., with two novel species: Thermolongibacillus altinsuensis sp. nov. (type strain E265(T) = DSM 24979(T) = NCIMB 14850(T)) and Thermolongibacillus kozakliensis sp. nov. (type strain E173a(T) = DSM 24978(T) = NCIMB 14849(T)).

  20. 生活垃圾填埋场甲烷自然减排的新途径:厌氧与好氧的共氧化作用%A new way of natural mitigation of methane in a refuse landfill: Anaerobic and aerobic co-oxidation

    Institute of Scientific and Technical Information of China (English)

    韩丹; 石峰; 柴晓利; 陈浩泉; 赵由才

    2011-01-01

    The surface soil at 30 ~60 cm, refuse at 1.5 m depth and the aged refuse at the bottom of the refuse landfill were selected for experiments on sulfate-reducing bacteria (SRB). It was found that SRB existed in nearly all layers of the solid waste landfill, with aged refuse at the bottom containing the most and the surface soil the least SRB. Garbage samples with a 50%: 50% coarse:fine particle size proportion showed the best aerobic and anaerobic methane oxidation effect, and anaerobic oxidation accounted for above 20%. Microbial activity in aged refuse and co-oxidation rate of methane reached a maximum value with a 25% moisture content. Anaerobic oxidation rate could reach more than 30% as the moisture content approached 70%. Supplementation of exogenous methane could shorten the time of aerobic oxidation by 50%. However, both aerobic and anaerobic oxidation were weakened if the amount of exogenous methane was beyond 2 mL for the 20 g aged refuse. Therefore, a new way for natural mitigation of methane in a refuse landfill is put forward based on anaerobic and aerobic co-oxidation of methane.%采用暴雨过后垃圾填埋表层30~60 cm的覆土、表层1.5 m以下的垃圾,以及刚刚开挖出来的9年矿化垃圾进行硫酸盐还原菌阳性反应试验,结果表明生活垃圾填埋体不同填埋层都存在不同数量级的硫酸盐还原菌,且底层矿化垃圾中的硫酸盐还原菌的数量最多,表层覆土中最少.颗粒大小比例为50%:50%的垃圾样品表现出最佳的甲烷好氧与厌氧氧化效果,且厌氧氧化在共氧化作用中的比例达到20%以上.含水率为25%时,矿化垃圾中微生物活性最大,好氧与厌氧氧化甲烷速率均达到最大.当含水率接近70%时,甲烷厌氧氧化的贡献率可达30%以上.外源甲烷的补充可以驯化甲烷氧化微生物,其中甲烷好氧氧化时间最大可缩短50%;而初始甲烷一次通人量超过2 mL(20g矿化垃圾)后,甲烷好氧与厌氧氧化

  1. 生活垃圾填埋场甲烷自然减排的新途径——厌氧与好氧的共氧化作用%New Way for Natural Mitigation of Methane in Domestic Waste Landfill Sites: Co-oxidation of Anaerobic and Aerobic Oxidation

    Institute of Scientific and Technical Information of China (English)

    周海燕; 韩丹

    2011-01-01

    通过证实生活垃圾填埋场中甲烷厌氧氧化与好氧氧化的共存,提出了甲烷自然减排的新途径.分别选取暴雨过后垃圾填埋表层30~60 cm的覆土、1.5 m以下的垃圾以及底层矿化垃圾做硫酸盐还原菌阳性反应实验,结果表明:生活垃圾填埋体不同填埋层都存在不同数量级的硫酸盐还原菌,且底层矿化垃圾中的硫酸盐还原菌的数量最多,表层覆土中最少.颗粒大小比例为50%:50%的垃圾样品表现出最佳的甲烷好氧与厌氧氧化效果,且厌氧氧化在共氧化作用中的比例达到20%以上.含水率为25%时,矿化垃圾中微生物活性最大,好氧与厌氧氧化甲烷速率均达到最大;当含水率接近70%时,甲烷厌氧氧化的贡献率可达30%以上.外源甲烷的补充可以驯化甲烷氧化微生物,其中甲烷好氧氧化时间最大可缩短50%;而甲烷通入量超过2 mL后,甲烷好氧与厌氧氧化均受到抑制.%A new way for natural mitigation of methane was put forward by authenticating co-oxidation of anaerobic and aerobic oxidation of methane in domestic waste landfill sites. The soil at 30-60 cm, the waste below 1.5 m from the surface, and the aged waste at the bottom, were selected for the experiments of sulfate-reducing bacteria positive reaction. The results showed that sulfate-reducing bacteria nearly existed in all landfill layers of waste landfill bodies, and aged waste at the bottom contained most, the surface soil contained least. Waste samples with 50%: 50% of coarse and fine particle size proportion showed the best methane oxidation effect of aerobic and anaerobic oxidation, and anaerobic oxidation accounted for above 20%. Microbial activity in aged waste and its methane co-oxidation rate both reached the maximum value as moisture content was 25%. Anaerobic oxidation rate could reach more than 30% as moisture content was close to 70%. Supplement of exogenous methane could culture methane-oxidizing bacteria

  2. Influence of thermophilic aerobic digestion as a sludge pre-treatment and solids retention time of mesophilic anaerobic digestion on the methane production, sludge digestion and microbial communities in a sequential digestion process.

    Science.gov (United States)

    Jang, Hyun Min; Cho, Hyun Uk; Park, Sang Kyu; Ha, Jeong Hyub; Park, Jong Moon

    2014-01-01

    In this study, the changes in sludge reduction, methane production and microbial community structures in a process involving two-stage thermophilic aerobic digestion (TAD) and mesophilic anaerobic digestion (MAD) under different solid retention times (SRTs) between 10 and 40 days were investigated. The TAD reactor (RTAD) was operated with a 1-day SRT and the MAD reactor (RMAD) was operated at three different SRTs: 39, 19 and 9 days. For a comparison, control MAD (RCONTROL) was operated at three different SRTs of 40, 20 and 10 days. Our results reveal that the sequential TAD-MAD process has about 42% higher methane production rate (MPR) and 15% higher TCOD removal than those of RCONTROL when the SRT decreased from 40 to 20 days. Denaturing gradient gel electrophoresis (DGGE) and real-time PCR results indicate that RMAD maintained a more diverse bacteria and archaea population compared to RCONTROL, due to the application of the biological TAD pre-treatment process. In RTAD, Ureibacillus thermophiles and Bacterium thermus were the major contributors to the increase in soluble organic matter. In contrast, Methanosaeta concilii, a strictly aceticlastic methanogen, showed the highest population during the operation of overall SRTs in RMAD. Interestingly, as the SRT decreased to 20 days, syntrophic VFA oxidizing bacteria, Clostridium ultunense sp., and a hydrogenotrophic methanogen, Methanobacterium beijingense were detected in RMAD and RCONTROL. Meanwhile, the proportion of archaea to total microbe in RMAD and RCONTROL shows highest values of 10.5 and 6.5% at 20-d SRT operation, respectively. Collectively, these results demonstrate that the increased COD removal and methane production at different SRTs in RMAD might be attributed to the increased synergism among microbial species by improving the hydrolysis of the rate limiting step in sludge with the help of the biological TAD pre-treatment. PMID:23871253

  3. Anaerobic thermophiles.

    Science.gov (United States)

    Canganella, Francesco; Wiegel, Juergen

    2014-01-01

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

  4. Anaerobic Thermophiles

    Directory of Open Access Journals (Sweden)

    Francesco Canganella

    2014-02-01

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

  5. Chthonomonas calidirosea gen. nov., sp. nov., an aerobic, pigmented, thermophilic micro-organism of a novel bacterial class, Chthonomonadetes classis nov., of the newly described phylum Armatimonadetes originally designated candidate division OP10.

    Science.gov (United States)

    Lee, Kevin C-Y; Dunfield, Peter F; Morgan, Xochitl C; Crowe, Michelle A; Houghton, Karen M; Vyssotski, Mikhail; Ryan, Jason L J; Lagutin, Kirill; McDonald, Ian R; Stott, Matthew B

    2011-10-01

    An aerobic, saccharolytic, obligately thermophilic, motile, non-spore-forming bacterium, strain T49(T), was isolated from geothermally heated soil at Hell's Gate, Tikitere, New Zealand. On the basis of 16S rRNA gene sequence similarity, T49(T) is the first representative of a new class in the newly described phylum Armatimonadetes, formerly known as candidate division OP10. Cells of strain T49(T) stained Gram-negative and were catalase-positive and oxidase-negative. Cells possessed a highly corrugated outer membrane. The major fatty acids were 16 : 0, i17 : 0 and ai17 : 0. The G+C content of the genomic DNA was 54.6 mol%. Strain T49(T) grew at 50-73 °C with an optimum temperature of 68 °C, and at pH 4.7-5.8 with an optimum growth pH of 5.3. A growth rate of 0.012 h(-1) was observed under optimal temperature and pH conditions. The primary respiratory quinone was MK-8. Optimal growth was achieved in the absence of NaCl, although growth was observed at NaCl concentrations as high as 2 % (w/v). Strain T49(T) was able to utilize mono- and disaccharides such as cellobiose, lactose, mannose and glucose, as well as branched or amorphous polysaccharides such as starch, CM-cellulose, xylan and glycogen, but not highly linear polysaccharides such as crystalline cellulose or cotton. On the basis of its phylogenetic position and phenotypic characteristics, we propose that strain T49(T) represents a novel bacterial genus and species within the new class Chthonomonadetes classis nov. of the phylum Armatimonadetes. The type strain of Chthonomonas calidirosea gen. nov., sp. nov. is T49(T) ( = DSM 23976(T) = ICMP 18418(T)). PMID:21097641

  6. CO oxidation on gold nanoparticles: Theoretical studies

    DEFF Research Database (Denmark)

    Remediakis, Ioannis; Lopez, Nuria; Nørskov, Jens Kehlet

    2005-01-01

    We present a summary of our theoretical results regarding CO oxidation on both oxide-supported and isolated gold nanoparticles. Using Density Functional Theory we have studied the adsorption of molecules and the oxidation reaction of CO on gold clusters. Low-coordinated sites on the gold nanopart......We present a summary of our theoretical results regarding CO oxidation on both oxide-supported and isolated gold nanoparticles. Using Density Functional Theory we have studied the adsorption of molecules and the oxidation reaction of CO on gold clusters. Low-coordinated sites on the gold...... efficiency of Au-based catalysts. Finally, our theoretical simulations allow us to discuss the selectivity of supported Au nanoparticles....

  7. CO oxidation on PdO surfaces

    DEFF Research Database (Denmark)

    Hirvi, Janne T.; Kinnunen, Toni-Jani J.; Suvanto, Mika;

    2010-01-01

    Density functional calculations were performed in order to investigate CO oxidation on two of the most stable bulk PdO surfaces. The most stable PdO(100) surface, with oxygen excess, is inert against CO adsorption, whereas strong adsorption on the stoichiometric PdO(101) surface leads to favorable...... oxidation via the Langmuir–Hinshelwood mechanism. The reaction with a surface oxygen atom has an activation energy of 0.66 eV, which is comparable to the lowest activation energies observed on metallic surfaces. However, the reaction rate may be limited by the coverage of molecular oxygen. Actually...... adsorption, following the Eley–Rideal mechanism and taking advantage of the reaction tunnel provided by the adjacent palladium atom, has an activation energy of only 0.24 eV. The reaction mechanism and activation energy for the palladium activated CO oxidation on the most stable PdO(100)–O surface...

  8. Properties of thermophilic microorganisms

    International Nuclear Information System (INIS)

    Microorganisms are called thermophilic or extreme thermophilic (caldo-active) if they grow and reproduce over 470C and 700C, respectively. A survey of growth characteristics of thermophiles is presented and it includes those which also live at extreme pH. The prevalent but not completely emcompassing theory of the ability of thermophiles to grow at high temperatures is that they have macromolecules and cell organelles with high thermostability. Work on some proteins and cell organelles from thermophiles is reviewed. The thermostabilities of these components are compared with those of the living cells, and factors which may govern optimum as well as minimum growth temperatures of microorganisms are discussed. Examples are from the literature but also include enzymes involved in tetrahydrofolate metabolism and other proteins of acetogenic therhmophilic bacteria which are presently studied in the author's laboratory

  9. Thermophilic Biohydrogen Production

    DEFF Research Database (Denmark)

    Karakashev, Dimitar Borisov; Angelidaki, Irini

    2011-01-01

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

  10. Draft Genome Sequence of Geobacillus subterraneus Strain K, a Hydrocarbon-Oxidizing Thermophilic Bacterium Isolated from a Petroleum Reservoir in Kazakhstan

    Science.gov (United States)

    Poltaraus, Andrey B.; Sokolova, Diyana S.; Grouzdev, Denis S.; Ivanov, Timophey M.; Malakho, Sophia G.; Korshunova, Alena V.; Tourova, Tatiyana P.

    2016-01-01

    The draft genome sequence of Geobacillus subterraneus strain K, a thermophilic aerobic oil-oxidizing bacterium isolated from production water of the Uzen high-temperature oil field in Kazakhstan, is presented here. The genome is annotated for elucidation of the genomic and phenotypic diversity of thermophilic alkane-oxidizing bacteria. PMID:27491973

  11. Thermophilic microorganisms in biomining.

    Science.gov (United States)

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

    2016-11-01

    Biomining is an applied biotechnology for mineral processing and metal extraction from ores and concentrates. This alternative technology for recovering metals involves the hydrometallurgical processes known as bioleaching and biooxidation where the metal is directly solubilized or released from the matrix for further solubilization, respectively. Several commercial applications of biomining can be found around the world to recover mainly copper and gold but also other metals; most of them are operating at temperatures below 40-50 °C using mesophilic and moderate thermophilic microorganisms. Although biomining offers an economically viable and cleaner option, its share of the world´s production of metals has not grown as much as it was expected, mainly considering that due to environmental restrictions in many countries smelting and roasting technologies are being eliminated. The slow rate of biomining processes is for sure the main reason of their poor implementation. In this scenario the use of thermophiles could be advantageous because higher operational temperature would increase the rate of the process and in addition it would eliminate the energy input for cooling the system (bioleaching reactions are exothermic causing a serious temperature increase in bioreactors and inside heaps that adversely affects most of the mesophilic microorganisms) and it would decrease the passivation of mineral surfaces. In the last few years many thermophilic bacteria and archaea have been isolated, characterized, and even used for extracting metals. This paper reviews the current status of biomining using thermophiles, describes the main characteristics of thermophilic biominers and discusses the future for this biotechnology. PMID:27628339

  12. Study on the CO Oxidation over Ceria-Based Nanocatalysts.

    Science.gov (United States)

    Piumetti, Marco; Andana, Tahrizi; Bensaid, Samir; Russo, Nunzio; Fino, Debora; Pirone, Raffaele

    2016-12-01

    A series of ceria nanocatalysts have been prepared to study the structure dependency of the CO oxidation reaction. The ceria samples with well-defined nanostructures (nanocubes/Ce-NC and nanorods/Ce-NR) have been prepared using the hydrothermal method. Mesoporous ceria (Ce-MES) and ceria synthesized with solution combustion technique (Ce-SCS) have also been prepared for comparison. The lowest CO oxidation temperature has been reached by using ceria nanocubes (Ce-NC). This high activity draws immense contributions from the highly reactive (100) and (110) surfaces of the truncated nanocubes. The Ce-MES and Ce-SCS samples, despite their high surface areas, are unable to outdo the activity of Ce-NC and Ce-NR due to the abundant presence of (111) crystalline planes. This finding confirms the structure sensitivity of CO oxidation reaction catalyzed with ceria. PMID:27009532

  13. Hydrogen Production by Thermophilic Fermentation

    NARCIS (Netherlands)

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

    2012-01-01

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

  14. Trends in the Catalytic CO Oxidation Activity of Nanoparticles

    DEFF Research Database (Denmark)

    Nørskov, Jens Kehlet; Falsig, Hanne; Larsen, Britt Hvolbæk;

    2008-01-01

    Going for gold: Density functional calculations show how gold nanoparticles are more active catalysts for CO oxidation than other metal nanoparticles. The high catalytic activity of nanosized gold clusters at low temperature is found to be related to the ability of low-coordinate metal atoms...

  15. CO oxidation on fully oxygen covered Ru(0001)

    DEFF Research Database (Denmark)

    Sljivancanin, Zeljko; Hammer, Bjørk

    2010-01-01

    We present a reaction mechanism for CO oxidation at the Ru(0001)-(1×1) surface. By means of density-functional theory studies, we compare the reactivity of flat and stepped regions of the Ru(0001). We find that at saturation oxygen coverage, where the flat parts are unreactive toward CO adsorption...

  16. Thermophilic degradation of cellulosic biomass

    Science.gov (United States)

    Ng, T.; Zeikus, J. G.

    1982-12-01

    The conversion of cellulosic biomass to chemical feedstocks and fuel by microbial fermentation is an important objective of developing biotechnology. Direct fermentation of cellulosic derivatives to ethanol by thermophilic bacteria offers a promising approach to this goal. Fermentations at elevated temperatures lowers the energy demand for cooling and also facilitates the recovery of volatile products. In addition, thermophilic microorganisms possess enzymes with greater stability than those from mesophilic microorganisms. Three anaerobic thermophilic cocultures that ferment cellulosic substrate mainly to ethanol have been described: Clostridium thermocellum/Clostriidium thermohydrosulfuricum, C. thermocellum/Clostridium thermosaccharolyticum, and C. thermocellum/Thermoanaerobacter ethanolicus sp. nov. The growth characteristics and metabolic features of these cocultures are reviewed.

  17. Catalytic activity trends of CO oxidation – A DFT study

    DEFF Research Database (Denmark)

    Jiang, Tao

    There are two goals of this thesis, the first one is to understand the reactivity of noble metal nanoparticles for CO oxidation reaction. The second goal is to gain understanding to the second derivative (Hessian matrix) of the potential energy surfaces (PES) of adsorption systems, especially its...... eigenmodes and eigenvalues, and improving algorithms for geometry optimization in electronic structure calculations. The catalytic activity of gold nanoparticles has received wide attention since the discovery of their activity on CO oxidation by Professor Haruta in 1987. By using density functional theory...... oxidation by molecular O2 occurs via a different reaction pathway, which instead involves a meta-stable intermediate CO-O2. However, although the two oxidizing agents used proceeded via different reaction pathways on different active sites, the apparent overall activation barriers obtained from both theory...

  18. Thermophilic molds: Biology and applications.

    Science.gov (United States)

    Singh, Bijender; Poças-Fonseca, Marcio J; Johri, B N; Satyanarayana, Tulasi

    2016-11-01

    Thermophilic molds thrive in a variety of natural habitats including soils, composts, wood chip piles, nesting materials of birds and other animals, municipal refuse and others, and ubiquitous in their distribution. These molds grow in simple media containing carbon and nitrogen sources and mineral salts. Polyamines are synthesized in these molds and the composition of lipids varies considerably, predominantly containing palmitic, oleic and linoleic acids with low levels of lauric, palmiotoleic and stearic acids. Thermophilic molds are capable of efficiently degrading organic materials by secreting thermostable enzymes, which are useful in the bioremediation of industrial wastes and effluents that are rich in oil, heavy metals, anti-nutritional factors such as phytic acid and polysaccharides. Thermophilic molds synthesize several antimicrobial substances and biotechnologically useful miscellaneous enzymes. The analysis of genomes of thermophilic molds reveals high G:C contents, shorter introns and intergenic regions with lesser repetitive sequences, and further confirms their ability to degrade agro-residues efficiently. Genetic engineering has aided in ameliorating the characteristics of the enzymes of thermophilic molds. This review is aimed at focusing on the biology of thermophilic molds with emphasis on recent developments in the analysis of genomes, genetic engineering and potential applications. PMID:26777293

  19. Methanogenesis in Thermophilic Biogas Reactors

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær

    1995-01-01

    against Methanothrix soehngenii or Methanothrix CALS-I in any of the thermophilic biogas reactors examined. Studies using 2-14C-labeled acetate showed that at high concentrations (more than approx. 1 mM) acetate was metabolized via the aceticlastic pathway, transforming the methyl-group of acetate...... microorganism into methane. In thermophilic biogas reactors,, acetate oxidizing cultures occupied the niche of Methanothrix species, aceticlastic methanogens which dominate at low acetate concentrations in mesophilic systems. Normally, thermophilic biogas reactors are operated at temperatures from 52 to 560 C....... Experiments using biogas reactors fed with cow manure showed that the same biogas yield found at 550 C could be obtained at 610 C after a long adaptation period. However, propionate degradation was inhibited by increasing the temperature....

  20. Extremely thermophilic microorganisms as metabolic engineering platforms for production of fuels and industrial chemicals.

    Science.gov (United States)

    Zeldes, Benjamin M; Keller, Matthew W; Loder, Andrew J; Straub, Christopher T; Adams, Michael W W; Kelly, Robert M

    2015-01-01

    Enzymes from extremely thermophilic microorganisms have been of technological interest for some time because of their ability to catalyze reactions of industrial significance at elevated temperatures. Thermophilic enzymes are now routinely produced in recombinant mesophilic hosts for use as discrete biocatalysts. Genome and metagenome sequence data for extreme thermophiles provide useful information for putative biocatalysts for a wide range of biotransformations, albeit involving at most a few enzymatic steps. However, in the past several years, unprecedented progress has been made in establishing molecular genetics tools for extreme thermophiles to the point that the use of these microorganisms as metabolic engineering platforms has become possible. While in its early days, complex metabolic pathways have been altered or engineered into recombinant extreme thermophiles, such that the production of fuels and chemicals at elevated temperatures has become possible. Not only does this expand the thermal range for industrial biotechnology, it also potentially provides biodiverse options for specific biotransformations unique to these microorganisms. The list of extreme thermophiles growing optimally between 70 and 100°C with genetic toolkits currently available includes archaea and bacteria, aerobes and anaerobes, coming from genera such as Caldicellulosiruptor, Sulfolobus, Thermotoga, Thermococcus, and Pyrococcus. These organisms exhibit unusual and potentially useful native metabolic capabilities, including cellulose degradation, metal solubilization, and RuBisCO-free carbon fixation. Those looking to design a thermal bioprocess now have a host of potential candidates to choose from, each with its own advantages and challenges that will influence its appropriateness for specific applications. Here, the issues and opportunities for extremely thermophilic metabolic engineering platforms are considered with an eye toward potential technological advantages for high

  1. Solubilization of Waste Activated Sludge and Nitrogenous Compounds Transformation During Solubilization by Thermophilic Enzyme (S-TE) Process.

    Science.gov (United States)

    Yang, Qi; Luo, Kun; Li, Xiao-ming; Zhong, Yu; Chen, Hong-bo; Yang, Guo-jing; Shi, Yan-wei; Zeng, Guang-ming

    2015-06-01

    A representative thermophilic bacterial strain (AT06-1) capable of secreting protease was isolated from thermophilic aerobic digestion reactor, and 16S rRNA gene analysis indicated that it was Bacillus sp. The isolated strain was inoculated in waste activated sludge (WAS) to evaluate the performance of solubilization by thermophilic enzyme (S-TE) process under aerobic or microaerobic conditions at different temperatures (55-70 °C). Results showed that the inoculation of specific thermophilic strain significantly affected the volatile suspended solids (VSS) removal. At the optimal temperature of 65 °C, the maximum VSS removal of 43.6 % and highest SCOD of 4475 mg/L was achieved during microaerobic S-TE process. Compared to the noninoculation, more soluble protein was released during S-TE process due to the higher protease activity associated with the protein hydrolysis originated from cell lysis. The protease activity at aerobic and microaerobic S-TE process was respectively 1.73 and 1.88 times that of the noninoculation. Ammonia was the end nitrogenous compound of protein hydrolysis during S-TE process, which was stripped from the digestion system through continuous aeration.

  2. Co Oxidation Properties Of Selective Dissoluted Metallic Glass Composites

    Directory of Open Access Journals (Sweden)

    Kim S.-Y.

    2015-06-01

    Full Text Available Porous metallic materials have been widely used in many fields including aerospace, atomic energy, electro chemistry and environmental protection. Their unique structures make them very useful as lightweight structural materials, fluid filters, porous electrodes and catalyst supports. In this study, we fabricated Ni-based porous metallic glasses having uniformly dispersed micro meter pores by the sequential processes of ball-milling and chemical dissolution method. We investigated the application of our porous metal supported for Pt catalyst. The oxidation test was performed in an atmosphere of 1% CO and 3% O2. Microstructure observation was performed by using a scanning electron microscope. Oxidation properties and BET (Brunauer, Emmett, and Teller were analyzed to understand porous structure developments. The results indicated that CO Oxidation reaction was dependent on the specific surface area.

  3. Thermophilic anaerobic digestion for waste and wastewater treatment.

    NARCIS (Netherlands)

    Wiegant, W.M.

    1986-01-01

    This thesis deals with thermophilic anaerobic waste and wastewater treatment. A literature survey is presented, in which the thermophilic treatment processes are evaluated with respect to the loading rates and treatment efficiencies, and some relevant theoretical considerations concerning thermophil

  4. Ethanol production by engineered thermophiles.

    Science.gov (United States)

    Olson, Daniel G; Sparling, Richard; Lynd, Lee R

    2015-06-01

    We compare a number of different strategies that have been pursued to engineer thermophilic microorganisms for increased ethanol production. Ethanol production from pyruvate can proceed via one of four pathways, which are named by the key pyruvate dissimilating enzyme: pyruvate decarboxylase (PDC), pyruvate dehydrogenase (PDH), pyruvate formate lyase (PFL), and pyruvate ferredoxin oxidoreductase (PFOR). For each of these pathways except PFL, we see examples where ethanol production has been engineered with a yield of >90% of the theoretical maximum. In each of these cases, this engineering was achieved mainly by modulating expression of native genes. We have not found an example where a thermophilic ethanol production pathway has been transferred to a non-ethanol-producing organism to produce ethanol at high yield. A key reason for the lack of transferability of ethanol production pathways is the current lack of understanding of the enzymes involved. PMID:25745810

  5. Gold nanoparticles supported on magnesium oxide for CO oxidation

    Directory of Open Access Journals (Sweden)

    Bogdanchikova Nina

    2011-01-01

    Full Text Available Abstract Au was loaded (1 wt% on a commercial MgO support by three different methods: double impregnation, liquid-phase reductive deposition and ultrasonication. Samples were characterised by adsorption of N2 at -96°C, temperature-programmed reduction, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. Upon loading with Au, MgO changed into Mg(OH2 (the hydroxide was most likely formed by reaction with water, in which the gold precursor was dissolved. The size range for gold nanoparticles was 2-12 nm for the DIM method and 3-15 nm for LPRD and US. The average size of gold particles was 5.4 nm for DIM and larger than 6.5 for the other methods. CO oxidation was used as a test reaction to compare the catalytic activity. The best results were obtained with the DIM method, followed by LPRD and US. This can be explained in terms of the nanoparticle size, well known to determine the catalytic activity of gold catalysts.

  6. Mesophilic anaerobic stabilization of sewage sludge. Mesophile anaerobe Klaerschlammstabilisierung mit aerober Folgebehandlung

    Energy Technology Data Exchange (ETDEWEB)

    Stoll, U.

    1988-01-01

    Sludges treated in two stages in experiments - 7 days of anaerobic treatment and 2 days of aerobic-thermophilic treatment - can be judged to be completely stabilized because of the stabilization parameters BOD/sub 5//COD ratio and respiratory activity. The degradation results obtained are comparable to or better than those of the 20-day digestion (reference process). For all aerobic processes under investigation a clear temperature increase in the aerobic reactor was measured because of the exothermal metabolic processes of the aerobic biocenosis. There was a temperature rise of 15/sup 0/C in the tests in the aerobic reactor even after longer digestion times of 15 and 20 days. The results of the epidemics and hygiene investigations show that a secondary aerobic-thermophilic stage after the mesophilic digestion with adequate marginal conditions - germ retention time of 23 hours in the aerobic reactor at process temperatures higher than 50/sup 0/C as well as charging in batch quantities - leads to a safe and complete decontamination. Under these process and operation conditions all salmonellae were killed and the number of the enterobacteriaceae in 1 g of sludge was always less than 1.000. (orig./EF).

  7. CO oxidation on Pt-modified Rh(111) electrodes.

    Science.gov (United States)

    Housmans, T H M; Feliu, J M; Gómez, R; Koper, M T M

    2005-08-12

    The CO electro-oxidation reaction was studied on platinum-modified Rh(111) electrodes in 0.5 M H2SO4 using cyclic voltammetry and chronoamperometry. The Pt-Rh(111) electrodes were generated during voltammetric cycles at 50 mV s(-1) in a 30 microM H2PtCl6 and 0.5 M H2SO4 solution. Surfaces generated by n deposition cycles were investigated (Ptn-Rh(111) with n=2, 4, 6, 8, 10, and 16). The blank cyclic voltammograms of these surfaces are characterized by a pronounced sharpening of the hydrogen/(bi)sulfate adsorption/desorption peaks, typical for Rh(111), and the appearance of contributions between 0.1 and 0.4 V, which were ascribed to hydrogen/(bi)sulfate adsorption/desorption on the deposited platinum. At higher potentials, the surface oxidation of Rh(111) is enhanced by the presence of platinum. The structure of the Pt-modified electrodes was investigated by STM imaging. At low Pt coverages (Pt2-Rh(111)), monoatomically high islands are formed, which grow three dimensionally as the number of deposition cycles increases. After eight cycles, the monolayer islands have grown in diameter and range from mono- to multiatomic height. At even higher Pt coverage (Pt16-Rh(111)), the islands grow to particles of approx. 10 nm in diameter, which are 5-6 atoms high. The CO stripping voltammetry on these surfaces is characterized by two peaks: A low-potential, structure-insensitive peak, ascribed to CO reacting at the platinum monolayer islands, whose onset is shifted 150, 250, and 100 mV negatively with respect to pure Rh(111), Pt(111), and polycrystalline Pt, respectively, indicating the enhanced CO electro-oxidation properties of the Pt overlayer system. A peak at higher potentials displays strong structure sensitivity (particle-size effect) and was ascribed to CO reacting on the islands of multiatomic height. Current-time transients recorded on the surface with the highest amount of monolayer islands (Pt4-Rh(111)) also indicate enhanced CO-oxidation kinetics. Comparison of

  8. First principle identification of SiC monolayer as an efficient catalyst for CO oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Sinthika, S., E-mail: ranjit.t@res.srmuniv.ac.in, E-mail: sinthika90@gmail.com; Thapa, Ranjit, E-mail: ranjit.t@res.srmuniv.ac.in, E-mail: sinthika90@gmail.com [SRM Research Institute, SRM University, Kattankulathur 603203, Tamil Nadu (India); Reddy, C. Prakash [Department of Physics and Nanotechnology, SRM University, Kattankulathur 603203, Tamil Nadu (India)

    2015-06-24

    Using density functional theory, we investigated the electronic properties of SiC monolayer and tested its catalytic activity toward CO oxidation. The planar nature of a SiC monolayer is found to stable and is a high band gap semiconductor. CO interacts physically with SiC surface, whereas O{sub 2} is adsorbed with moderate binding. CO oxidation on SiC monolayer prefers the Eley Rideal mechanism over the Langmuir Hinshelwood mechanism, with an easily surmountable activation barrier during CO{sub 2} formation. Overall metal free SiC monolayer can be used as efficient catalyst for CO oxidation.

  9. Aerobic exercise (image)

    Science.gov (United States)

    Aerobic exercise gets the heart working to pump blood through the heart more quickly and with more force than ... must be oxygenated more quickly, which quickens respiration. Aerobic exercise strengthens the heart and boosts healthy cholesterol ...

  10. Acid-Tolerant Moderately Thermophilic Methanotrophs of the Class Gammaproteobacteria Isolated From Tropical Topsoil with Methane Seeps

    OpenAIRE

    Islam, Tajul; Torsvik, Vigdis; Larsen, Øivind; Bodrossy, Levente; Øvreås, Lise; Birkeland, Nils-Kåre

    2016-01-01

    Terrestrial tropical methane seep habitats are important ecosystems in the methane cycle. Methane oxidizing bacteria play a key role in these ecosystems as they reduce methane emissions to the atmosphere. Here, we describe the isolation and initial characterization of two novel moderately thermophilic and acid-tolerant obligate methanotrophs, assigned BFH1 and BFH2 recovered from a tropical methane seep topsoil habitat. The new isolates were strictly aerobic, non-motile, coccus-shaped and uti...

  11. Consolidated bioprocessing method using thermophilic microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Mielenz, Jonathan Richard

    2016-02-02

    The present invention is directed to a method of converting biomass to biofuel, and particularly to a consolidated bioprocessing method using a co-culture of thermophilic and extremely thermophilic microorganisms which collectively can ferment the hexose and pentose sugars produced by degradation of cellulose and hemicelluloses at high substrate conversion rates. A culture medium therefor is also provided as well as use of the methods to produce and recover cellulosic ethanol.

  12. CO oxidation catalyzed by silicon carbide (SiC) monolayer: A theoretical study.

    Science.gov (United States)

    Wang, Nan; Tian, Yu; Zhao, Jingxiang; Jin, Peng

    2016-05-01

    Developing metal-free catalysts for CO oxidation has been a key scientific issue in solving the growing environmental problems caused by CO emission. In this work, the potential of the silicon carbide (SiC) monolayer as a metal-free catalyst for CO oxidation was systematically explored by means of density functional theory (DFT) computations. Our results revealed that CO oxidation reaction can easily proceed on SiC nanosheet, and a three-step mechanism was proposed: (1) the coadsorption of CO and O2 molecules, followed by (2) the formation of the first CO2 molecule, and (3) the recovery of catalyst by a second CO molecule. The last step is the rate-determining one of the whole catalytic reaction with the highest barrier of 0.65eV. Remarkably, larger curvature is found to have a negative effect on the catalytic performance of SiC nanosheet for CO oxidation. Therefore, our results suggested that flat SiC monolayer is a promising metal-free catalyst for CO oxidation.

  13. Variations of culturable thermophilic microbe numbers and bacterial communities during the thermophilic phase of composting.

    Science.gov (United States)

    Li, Rong; Li, Linzhi; Huang, Rong; Sun, Yifei; Mei, Xinlan; Shen, Biao; Shen, Qirong

    2014-06-01

    Composting is a process of stabilizing organic wastes through the degradation of biodegradable components by microbial communities under controlled conditions. In the present study, genera and species diversities, amylohydrolysis, protein and cellulose degradation abilities of culturable bacteria in the thermophilic phase of composting of cattle manure with plant ash and rice bran were investigated. The number of culturable thermophilic bacteria and actinomyces decreased with the increasing temperature. At the initiation and end of the thermophilic phase, genera and specie diversities and number of bacteria possessing degradation abilities were higher than during the middle phase. During the thermophilic composting phase, Bacillus, Geobacillus and Ureibacillus were the dominant genera, and Geobacillus thermodenitrificans was the dominant species. In later thermophilic phases, Geobacillus toebii and Ureibacillus terrenus were dominant. Bacillus, at the initiation, and Ureibacillus and Geobacillus, at the later phase, contributed the multiple degradation abilities. These data will facilitate the control of composting in the future. PMID:24415499

  14. On the mechanism of hydrogen-promoted gold-catalyzed CO oxidation

    KAUST Repository

    Quinet, Elodie

    2009-12-10

    The kinetics of CO oxidation, H2 oxidation and preferential CO oxidation (PrOx) over Au/Al2O3 catalysts have been investigated. The catalysts with the smallest particles (∼2 nm) are the most active for all three reactions. As previously observed, the presence of H2 greatly promotes CO oxidation, which becomes faster than CO-free H2 oxidation at low temperature. From these results and on the basis of previous works, we propose a complete PrOx mechanism. The reaction involves Au-OOH, Au-OH and Au-H intermediates, also involved in H2 oxidation, and benefits from the presence of low-coordination sites. © 2009 Elsevier Inc. All rights reserved.

  15. Comparison of static, in-vessel composting of MSW with thermophilic anaerobic digestion and combinations of the two processes.

    Science.gov (United States)

    Walker, Lee; Charles, Wipa; Cord-Ruwisch, Ralf

    2009-08-01

    The biological stabilisation of the organic fraction of municipal solid waste (OFMSW) into a form stable enough for land application can be achieved via aerobic or anaerobic treatments. To investigate the rates of degradation (e.g. via electron equivalents removed, or via carbon emitted) of aerobic and anaerobic treatment, OFMSW samples were exposed to computer controlled laboratory-scale aerobic (static in-vessel composting), and anaerobic (thermophilic anaerobic digestion with liquor recycle) treatment individually and in combination. A comparison of the degradation rates, based on electron flow revealed that provided a suitable inoculum was used, anaerobic digestion was the faster of the two waste conversion process. In addition to faster maximum substrate oxidation rates, anaerobic digestion (followed by post-treatment aerobic maturation), when compared to static composting alone, converted a larger fraction of the organics to gaseous end-products (CO2 and CH4), leading to improved end-product stability and maturity, as measured by compost self-heating and root elongation tests, respectively. While not comparable to windrow and other mixed, highly aerated compost systems, our results show that in the thermophilic, in-vessel treatment investigated here, the inclusion of a anaerobic phase, rather than using composting alone, improved hydrolysis rates as well as oxidation rates and product stability. The combination of the two methods, as used in the DiCOM process, was also tested allowing heat generation to thermophilic operating temperature, biogas recovery and a low odour stable end-product within 19 days of operation. PMID:19345576

  16. Role of Mn2+ and Compatible Solutes in the Radiation Resistance of Thermophilic Bacteria and Archaea

    Directory of Open Access Journals (Sweden)

    Kimberly M. Webb

    2012-01-01

    Full Text Available Radiation-resistant bacteria have garnered a great deal of attention from scientists seeking to expose the mechanisms underlying their incredible survival abilities. Recent analyses showed that the resistance to ionizing radiation (IR in the archaeon Halobacterium salinarum is dependent upon Mn-antioxidant complexes responsible for the scavenging of reactive oxygen species (ROS generated by radiation. Here we examined the role of the compatible solutes trehalose, mannosylglycerate, and di-myo-inositol phosphate in the radiation resistance of aerobic and anaerobic thermophiles. We found that the IR resistance of the thermophilic bacteria Rubrobacter xylanophilus and Rubrobacter radiotolerans was highly correlated to the accumulation of high intracellular concentration of trehalose in association with Mn, supporting the model of Mn2+-dependent ROS scavenging in the aerobes. In contrast, the hyperthermophilic archaea Thermococcus gammatolerans and Pyrococcus furiosus did not contain significant amounts of intracellular Mn, and we found no significant antioxidant activity from mannosylglycerate and di-myo-inositol phosphate in vitro. We therefore propose that the low levels of IR-generated ROS under anaerobic conditions combined with highly constitutively expressed detoxification systems in these anaerobes are key to their radiation resistance and circumvent the need for the accumulation of Mn-antioxidant complexes in the cell.

  17. Bioleaching of marmatite using moderately thermophilic bacteria

    Institute of Scientific and Technical Information of China (English)

    ZHOU Hong-bo; LIU Fei-fei; ZOU Ying-qin; ZENG Xiao-xi; QIU Guan-zhou

    2008-01-01

    The process of bioleaching marmatite using moderately thermophilic bacteria was studied by comparing marmatite leaching performance of mesophiles and moderate thermophiles and valuating the effect of venting capacity as well as pulp density on marmatite leaching performance of moderate thermophiles. The results show that moderate thermophiles have more advantages over mesophilies in bioleaching marmatite at 45℃ and the pulp density of 50g/L, and the zinc extraction efficiency reaches 93.1% in 20d. Aeration agitation can improve the transfer of O2 and CO2 in solution and promote the growth of bacteria and therefore, enhance the leaching efficiency. Under the venting levels of 50, 200 and 800mL/min, the zinc extraction efficiencies by moderate thermophiles are 57.8%, 92.5% and 96.0%, respectively. With the increase of pulp density, the total leaching amount of valuable metals increases, however, the extraction efficiency decreases due to many reasons, such as increasing shear force leading to poorly growth condition for bacteria, etc. The zinc extraction decreases remarkably to 58.9% while the pulp density mounts up 20%.

  18. Status on Science and Application of Thermophilic Anaerobic Digestion

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær

    1994-01-01

    Thermophilic anaerobic processes are often regarded as less stable than mesophilic processes. In the paper this postulate is examined and disproved based on real operational data from of full-scale mesophilic and thermophilic biogas plants. The start-up produce for the thermophilic plants was, ho...

  19. PtRu colloid nanoparticles for CO oxidation in microfabricated reactors

    DEFF Research Database (Denmark)

    Klerke, Asbjørn; Saadi, Souheil; Toftegaard, Maja Bøg;

    2006-01-01

    The catalytic activity of PtRu colloid nanoparticles for CO oxidation is investigated in microfabricated reactors. The measured catalytic performance describes a volcano curve as a function of the Pt/Ru ratio. The apparent activation energies for the different alloy catalysts are between 21 and 117...

  20. Bioprospecting thermophiles for cellulase production: a review

    Directory of Open Access Journals (Sweden)

    Somen Acharya

    2012-09-01

    Full Text Available Most of the potential bioprospecting is currently related to the study of the extremophiles and their potential use in industrial processes. Recently microbial cellulases find applications in various industries and constitute a major group of industrial enzymes. Considerable amount of work has been done on microbial cellulases, especially with resurgence of interest in biomass ethanol production employing cellulases and use of cellulases in textile and paper industry. Most efficient method of lignocellulosic biomass hydrolysis is through enzymatic saccharification using cellulases. Significant information has also been gained about the physiology of thermophilic cellulases producers and process development for enzyme production and biomass saccharification. The review discusses the current knowledge on cellulase producing thermophilic microorganisms, their physiological adaptations and control of cellulase gene expression. It discusses the industrial applications of thermophilic cellulases, their cost of production and challenges in cellulase research especially in the area of improving process economics of enzyme production.

  1. Pyrinomonas methylaliphatogenes gen. nov., sp. nov., a novel group 4 thermophilic member of the phylum Acidobacteria from geothermal soils

    OpenAIRE

    Crowe, M.A.; Power, J.F.; Morgan, X.C.; Dunfield, P.F.; Lagutin, K.; Rijpstra, W.I.C.; Vyssotski, M.; Sinninghe Damsté, J.S.; Houghton, K.M.; Ryan, J.L.J.; Stott, M.B.

    2014-01-01

    An aerobic, thermophilic, moderately acidophilic non-spore-forming bacterium, strain K22T, wasisolated from geothermally heated soil at Mount Ngauruhoe, New Zealand. On the basis of 16SrRNA gene sequence similarity, K22T was shown to belong to subdivision 4 of the phylumAcidobacteria and to be most closely related to ‘Candidatus Chloracidobacterium thermophilum’(86 %) and Blastocatella fastidiosa (86 %). Cells stained Gram-negative and were catalase andoxidase-positive. The major fatty acids ...

  2. [Pilot study of thermal treatment/thermophilic anaerobic digestion process treating waste activated sludge of high solid content].

    Science.gov (United States)

    Wu, Jing; Wang, Guang-qi; Cao, Zhi-ping; Li, Zhong-hua; Hu, Yu-ying; Wang, Kai-jun; Zu, Jian-e

    2014-09-01

    A pilot-scale experiment about the process of "thermal pretreatment at 70°C/thermophilic anaerobic digestion" of waste activated sludge of high solid content (8% -9% ) was conducted. The process employed thermal treatment of 3 days to accelerate the hydrolysis and thermophilic digestion to enhance anaerobic reaction. Thus it was good at organic removal and stabilization. When the solid retention time (SRT) was longer than 20 days, the VSS removal rate was greater than 42. 22% and it was linearly correlated to the SRT of the aerobic digestion with the R2 of 0. 915 3. It was suggested that SRT of anaerobic digestion was 25 days in practice. VSS removal rate and biogas production rate of the pilot experiment were similar to those of the run-well traditional full-scale sludge anaerobic digestion plants (solid content 3% -5% ) and the plant of high solid content using German technique.

  3. What Is Aerobic Dancing?

    Science.gov (United States)

    ... after exercising, see a physician. Common Aerobics Injuries Plantar fasciitis (arch pain) -- Arch pain is often caused by ... rearfoot instability, with excessive pronation, may result in plantar fasciitis. Shoes with proper support in the arch often ...

  4. Are thermophilic microorganisms active in cold environments?

    Science.gov (United States)

    Cockell, Charles S.; Cousins, Claire; Wilkinson, Paul T.; Olsson-Francis, Karen; Rozitis, Ben

    2015-07-01

    The mean air temperature of the Icelandic interior is below 10 °C. However, we have previously observed 16S rDNA sequences associated with thermophilic lineages in Icelandic basalts. Measurements of the temperatures of igneous rocks in Iceland showed that solar insolation of these low albedo substrates achieved a peak surface temperature of 44.5 °C. We isolated seven thermophilic Geobacillus species from basalt with optimal growth temperatures of ~65 °C. The minimum growth temperature of these organisms was ~36 °C, suggesting that they could be active in the rock environment. Basalt dissolution rates at 40 °C were increased in the presence of one of the isolates compared to abiotic controls, showing its potential to be involved in active biogeochemistry at environmental temperatures. These data raise the possibility of transient active thermophilic growth in macroclimatically cold rocky environments, implying that the biogeographical distribution of active thermophiles might be greater than previously understood. These data show that temperatures measured or predicted over large scales on a planet are not in themselves adequate to assess niches available to extremophiles at micron scales.

  5. Thermophilic starter cultures: another set of problems

    OpenAIRE

    Oberg, C. J.; Broadbent, Jeffery R.

    1993-01-01

    Increased consumer demand for yogurt and Italian cheeses, particularly Mozzarella, over the past decade has intensified production demands on thermophilic starter cultures. Dramatically elevated production rates within existing facilities have created problems analogous to those experienced years ago by the dairy industry for mesophilic lactococci when Cheddar cheese production increased dramatically. In contrast to mesophilic lactococci, however, diversity among lactic genera that contain th...

  6. A thermophilic microbial fuel cell design

    Science.gov (United States)

    Carver, Sarah M.; Vuoriranta, Pertti; Tuovinen, Olli H.

    Microbial fuel cells (MFCs) are reactors able to generate electricity by capturing electrons from the anaerobic respiratory processes of microorganisms. While the majority of MFCs have been tested at ambient or mesophilic temperatures, thermophilic systems warrant evaluation because of the potential for increased microbial activity rates on the anode. MFC studies at elevated temperatures have been scattered, using designs that are already established, specifically air-cathode single chambers and two-chamber designs. This study was prompted by our previous attempts that showed an increased amount of evaporation in thermophilic MFCs, adding unnecessary technical difficulties and causing excessive maintenance. In this paper, we describe a thermophilic MFC design that prevents evaporation. The design was tested at 57 °C with an anaerobic, thermophilic consortium that respired with glucose to generate a power density of 375 mW m -2 after 590 h. Polarization and voltage data showed that the design works in the batch mode but the design allows for adoption to continuous operation.

  7. The superior catalytic CO oxidation capacity of a Cr-phthalocyanine porous sheet

    Science.gov (United States)

    Li, Yawei; Sun, Qiang

    2014-02-01

    Two-dimensional organometallic sheets containing regularly and separately distributed transition atoms (TMs) have received tremendous attentions due to their flexibility in synthesis, well-defined geometry and the promising applications in hydrogen storage, electronic circuits, quantum Hall effect, and spintronics. Here for the first time we present a study on the superior catalytic CO oxidation capacity of a Cr-phthalocyanine porous sheet proceeding first via Langmuir-Hinshelwood (LH) mechanism and then via Eley-Rideal (ER) mechanism. Compared to the noble metal based catalysts or graphene supported catalysts, our studied system has following unique features: without poisoning effect and clustering problem, having comparable reaction energy barrier for low-temperature oxidation, and low cost for large-scale catalytic CO oxidation in industry.

  8. Bond energies in polyunsaturated acids and kinetics of co-oxidation of protiated and deuterated acids

    Science.gov (United States)

    Andrianova, Z. S.; Breslavskaya, N. N.; Pliss, E. M.; Buchachenko, A. L.

    2016-10-01

    A computational program specially designed to analyze co-oxidation of substances in mixtures is suggested. The rigorous kinetic scheme of 32 reactions describing co-oxidation of isotope differing polyunsaturated fatty acids was computed to enlighten experimentally detected enormously large H/D isotope effects. The latter were shown to depend on the kinetic chain length and exhibit two extreme regimes of short and long chains which characterize isotope effects on the initiation and propagation chain reactions of hydrogen (deuterium) atom abstraction. No protective effect of deuterated polyunsaturated acids on the oxidation of protiated acids was detected. Protective effect of the deuterated compounds on the biologically important processes seems to be induced by the low yield of products formed in the chain termination reactions due to the low rate of initiation by deuterated compounds.

  9. Transition-Metal Doped Ceria Microspheres with Nanoporous Structures for CO Oxidation

    Science.gov (United States)

    Zhou, Lin; Li, Xiaoxiao; Yao, Ze; Chen, Zhuwen; Hong, Mei; Zhu, Rongshu; Liang, Yongye; Zhao, Jing

    2016-03-01

    Catalytic oxidation of carbon monoxide (CO) is of great importance in many different fields of industry. Until now it still remains challenging to use non-noble metal based catalysts to oxidize CO at low temperature. Herein, we report a new class of nanoporous, uniform, and transition metal-doped cerium (IV) oxide (ceria, CeO2) microsphere for CO oxidation catalysis. The porous and uniform microsphere is generated by sacrificed polymer template. Transition-metals, like Cu, Co, Ni, Mn and Fe, were doped into CeO2 microspheres. The combination of hierarchical structure and metal doping afford superior catalytic activities of the doped ceria microspheres, which could pave a new way to advanced non-precious metal based catalysts for CO oxidation.

  10. Formic Acid Modified Co3O4-CeO2 Catalysts for CO Oxidation

    Directory of Open Access Journals (Sweden)

    Ruishu Shang

    2016-03-01

    Full Text Available A formic acid modified catalyst, Co3O4-CeO2, was prepared via facile urea-hydrothermal method and applied in CO oxidation. The Co3O4-CeO2-0.5 catalyst, treated by formic acid at 0.5 mol/L, performed better in CO oxidation with T50 obtained at 69.5 °C and T100 obtained at 150 °C, respectively. The characterization results indicate that after treating with formic acid, there is a more porous structure within the Co3O4-CeO2 catalyst; meanwhile, despite of the slightly decreased content of Co, there are more adsorption sites exposed by acid treatment, as suggested by CO-TPD and H2-TPD, which explains the improvement of catalytic performance.

  11. CO oxidation catalyzed by Pt-embedded graphene: A first-principles investigation

    KAUST Repository

    Liu, Xin

    2014-01-01

    We addressed the potential catalytic role of Pt-embedded graphene in CO oxidation by first-principles-based calculations. We showed that the combination of highly reactive Pt atoms and defects over graphene makes the Pt-embedded graphene a superior mono-dispersed atomic catalyst for CO oxidation. The binding energy of a single Pt atom onto monovacancy defects is up to -7.10 eV, which not only ensures the high stability of the embedded Pt atom, but also vigorously excludes the possibility of diffusion and aggregation of embedded Pt atoms. This strong interfacial interaction also tunes the energy level of Pt-d states for the activation of O2, and promotes the formation and dissociation of the peroxide-like intermediate. The catalytic cycle of CO oxidation is initiated through the Langmuir-Hinshelwood mechanism, with the formation of a peroxide-like intermediate by the coadsorbed CO and O2, by the dissociation of which the CO2 molecule and an adsorbed O atom are formed. Then, another gaseous CO will react with the remnant O atom and make the embedded Pt atom available for the subsequent reaction. The calculated energy barriers for the formation and dissociation of the peroxide-like intermediate are as low as 0.33 and 0.15 eV, respectively, while that for the regeneration of the embedded Pt atom is 0.46 eV, indicating the potential high catalytic performance of Pt-embedded graphene for low temperature CO oxidation.

  12. Promotion of CO oxidation on PdO(101) by adsorbed H2O

    Science.gov (United States)

    Choi, Juhee; Pan, Li; Mehar, Vikram; Zhang, Feng; Asthagiri, Aravind; Weaver, Jason F.

    2016-08-01

    We investigated the influence of adsorbed H2O on the oxidation of CO on PdO(101) using temperature programmed reaction spectroscopy (TPRS), reflection absorption infrared spectroscopy (RAIRS) and density functional theory (DFT) calculations. We find that water inhibits CO adsorption on PdO(101) by site blocking, but also provides a more facile pathway for CO oxidation compared with the bare oxide surface. In the presence of adsorbed H2O, the oxidation of CO on PdO(101) produces a CO2 TPRS peak that is centered at a temperature ~ 50 K lower than the main CO2 TPRS peak arising from CO oxidation on clean PdO(101) (~ 330 vs. 380 K). RAIRS shows that CO continues to adsorb on atop-Pd sites of PdO(101) when H2O is co-adsorbed, and provides no evidence of other reactive intermediates. DFT calculations predict that the CO oxidation mechanism follows the same steps for CO adsorbed on PdO(101) with and without co-adsorbed H2O, wherein an atop-CO species recombines with an oxygen atom from the oxide surface lattice. According to DFT, hydrogen bonding interactions with adsorbed H2O species stabilize the carboxyl-like transition structure and intermediate that result from the initial recombination of CO and O on the PdO(101) surface. This stabilization lowers the energy barrier for CO oxidation on PdO(101) by ~ 10 kJ/mol, in good agreement with our experimental estimate.

  13. Session 4: Low-temperature CO oxidation on Ni-Pt/SiO{sub 2} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Arenas-Alatorre, J.; Gomez-Cortes, A.; Diaz, G. [Instituto de Fisica UNAM, Mexico, D.F. (Mexico); Avalos Borja, M [Centro de Cciencias de la Materia Condensada, Ensenada, B.C. (Mexico)

    2004-07-01

    In the present study a set of Ni-Pt catalysts supported on silica have been examined as catalysts for the CO oxidation in the presence of hydrogen. The obtained results show that bimetallic Ni{sub 25}Pt{sub 75} catalyst is very active; total conversion of CO is achieved at 70 C and no significant diminution is observed at higher temperatures. Hydrogen concentration in the gas phase did not changed significantly indicating a very good selectivity towards CO oxidation. Bimetallic Ni{sub 50}Pt{sub 50} and Ni{sub 75}Pt{sub 25} catalysts showed also a good activity but the selectivity for CO oxidation decreases in favor of hydrogen oxidation at higher temperatures. It is interesting to note the performance of mono-metallic Ni/SiO{sub 2} since nickel is known to be not very active for oxidation reactions; at 120 C more than 80% of the CO is converted. On the other hand, Pt/SiO{sub 2} performance is not so good in comparison. (authors)

  14. Gold-Iron Oxide Catalyst for CO Oxidation: Effect of Support Structure

    Directory of Open Access Journals (Sweden)

    Hui-Zhen Cui

    2016-03-01

    Full Text Available Gold-iron oxide (Au/FeOx is one of the highly active catalysts for CO oxidation, and is also a typical system for the study of the chemistry of gold catalysis. In this work, two different types of iron oxide supports, i.e., hydroxylated (Fe_OH and dehydrated iron oxide (Fe_O, have been used for the deposition of gold via a deposition-precipitation (DP method. The structure of iron oxide has been tuned by either selecting precipitated pH of 6.7–11.2 for Fe_OH or changing calcination temperature of from 200 to 600 °C for Fe_O. Then, 1 wt. % Au catalysts on these iron oxide supports were measured for low-temperature CO oxidation reaction. Both fresh and used samples have been characterized by multiple techniques including transmission electron microscopy (TEM and high-resolution TEM (HRTEM, X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, X-ray absorption near edge structure (XANES and temperature-programmed reduction by hydrogen (H2-TPR. It has been demonstrated that the surface properties of the iron oxide support, as well as the metal-support interaction, plays crucial roles on the performance of Au/FeOx catalysts in CO oxidation.

  15. CO oxidation on nanoporous gold: A combined TPD and XPS study of active catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Röhe, Sarah [Univ. of Bremen (Germany). Inst. of Applied and Physical Chemistry; Frank, Kristian [Univ. of Bremen (Germany). Inst. of Solid State Physics; Schaefer, Andreas [Univ. of Bremen (Germany). Inst. of Applied and Physical Chemistry; Wittstock, Arne [Univ. of Bremen (Germany). Inst. of Applied and Physical Chemistry; Zielasek, Volkmar [Univ. of Bremen (Germany). Inst. of Applied and Physical Chemistry; Rosenauer, Andreas [Univ. of Bremen (Germany). Inst. of Solid State Physics; Bäumer, Marcus [Univ. of Bremen (Germany). Inst. of Applied and Physical Chemistry

    2012-11-30

    Disks of nanoporous gold (np-Au), produced by leaching of silver from AgAu alloy and prepared as active catalysts for CO oxidation in a continuous-flow reactor, were investigated in detail by x-ray photoelectron spectroscopy and temperature-programmed desorption spectroscopy in ultra-high vacuum. Np-Au exhibits several oxygen species on and in the surface: Chemisorbed oxygen (Oact), probably generated at residual silver sites at the surface, is readily available after np-Au preparation and consumed by CO oxidation. It can be replenished on activated np-Au by exposure to O2. In addition, strongly bound oxygen, probably at subsurface sites, is present as a major species and not consumed by CO oxidation. Pronounced CO desorption at temperatures above 200 K observed after exposing np-Au to CO at 105 K indicates an additional, more stable type of CO binding sites on np-Au as compared to pure gold. Only CO at these binding sites is consumed by oxidation reaction with Oact. In conclusion, we propose that the presence of strongly bound subsurface oxygen stabilizes CO adsorption on np-Au, thereby being as crucial for the observed catalytic activity of np-Au as residual silver.

  16. Thermophilic, lignocellulolytic bacteria for ethanol production: current state and perspectives

    DEFF Research Database (Denmark)

    Chang, Tinghong; Yao, Shuo

    2011-01-01

    for efficient biomass hydrolysis. Secondly, thermophilic bacteria ferment a broad range of carbohydrates into ethanol, and some of them display potential for ethanologenic fermentation at high yield. Thirdly, the establishment of the genetic tools for thermophilic bacteria has allowed metabolic engineering...... of cellulolytic and saccharolytic thermophilic bacteria for lignocellulosic ethanol production because of their unique properties. First of all, thermophilic bacteria possess unique cellulolytic and hemicellulolytic systems and are considered as potential sources of highly active and thermostable enzymes......, in particular with emphasis on improving ethanol yield, and this facilitates their employment for ethanol production. Finally, different processes for second-generation ethanol production based on thermophilic bacteria have been proposed with the aim to achieve cost-competitive processes. However, thermophilic...

  17. Discrimination of thermophilic and mesophilic proteins

    Directory of Open Access Journals (Sweden)

    Vaisman Iosif I

    2010-05-01

    Full Text Available Abstract Background There is a considerable literature on the source of the thermostability of proteins from thermophilic organisms. Understanding the mechanisms for this thermostability would provide insights into proteins generally and permit the design of synthetic hyperstable biocatalysts. Results We have systematically tested a large number of sequence and structure derived quantities for their ability to discriminate thermostable proteins from their non-thermostable orthologs using sets of mesophile-thermophile ortholog pairs. Most of the quantities tested correspond to properties previously reported to be associated with thermostability. Many of the structure related properties were derived from the Delaunay tessellation of protein structures. Conclusions Carefully selected sequence based indices discriminate better than purely structure based indices. Combined sequence and structure based indices improve performance somewhat further. Based on our analysis, the strongest contributors to thermostability are an increase in ion pairs on the protein surface and a more strongly hydrophobic interior.

  18. Thermophilic biohydrogen production: how far are we?

    Science.gov (United States)

    Pawar, Sudhanshu S; van Niel, Ed W J

    2013-09-01

    Apart from being applied as an energy carrier, hydrogen is in increasing demand as a commodity. Currently, the majority of hydrogen (H2) is produced from fossil fuels, but from an environmental perspective, sustainable H2 production should be considered. One of the possible ways of hydrogen production is through fermentation, in particular, at elevated temperature, i.e. thermophilic biohydrogen production. This short review recapitulates the current status in thermophilic biohydrogen production through fermentation of commercially viable substrates produced from readily available renewable resources, such as agricultural residues. The route to commercially viable biohydrogen production is a multidisciplinary enterprise. Microbiological studies have pointed out certain desirable physiological characteristics in H2-producing microorganisms. More process-oriented research has identified best applicable reactor types and cultivation conditions. Techno-economic and life cycle analyses have identified key process bottlenecks with respect to economic feasibility and its environmental impact. The review has further identified current limitations and gaps in the knowledge, and also deliberates directions for future research and development of thermophilic biohydrogen production. PMID:23948723

  19. Thermophilic methane production and oxidation in compost.

    Science.gov (United States)

    Jäckel, Udo; Thummes, Kathrin; Kämpfer, Peter

    2005-04-01

    Methane cycling within compost heaps has not yet been investigated in detail. We show that thermophilic methane oxidation occurred after a lag phase of up to one day in 4-week old, 8-week old and mature (>10-week old) compost material. The potential rate of methane oxidation was between 2.6 and 4.1 micromol CH4(gdw)(-1)h(-1). Profiles of methane concentrations within heaps of different ages indicated that 46-98% of the methane produced was oxidised by methanotrophic bacteria. The population size of thermophilic methanotrophs was estimated at 10(9) cells (gdw)(-1), based on methane oxidation rates. A methanotroph (strain KTM-1) was isolated from the highest positive step of a serial dilution series. This strain belonged to the genus Methylocaldum, which contains thermotolerant and thermophilic methanotrophs. The closest relative organism on the basis of 16S rRNA gene sequence identity was M. szegediense (>99%), a species originally isolated from hot springs. The temperature optimum (45-55 degrees C) for methane oxidation within the compost material was identical to that of strain KTM-1, suggesting that this strain was well adapted to the conditions in the compost material. The temperatures measured in the upper layer (0-40 cm) of the compost heaps were also in this range, so we assume that these organisms are capable of effectively reducing the potential methane emissions from compost.

  20. Thermophilic biohydrogen production: how far are we?

    Science.gov (United States)

    Pawar, Sudhanshu S; van Niel, Ed W J

    2013-09-01

    Apart from being applied as an energy carrier, hydrogen is in increasing demand as a commodity. Currently, the majority of hydrogen (H2) is produced from fossil fuels, but from an environmental perspective, sustainable H2 production should be considered. One of the possible ways of hydrogen production is through fermentation, in particular, at elevated temperature, i.e. thermophilic biohydrogen production. This short review recapitulates the current status in thermophilic biohydrogen production through fermentation of commercially viable substrates produced from readily available renewable resources, such as agricultural residues. The route to commercially viable biohydrogen production is a multidisciplinary enterprise. Microbiological studies have pointed out certain desirable physiological characteristics in H2-producing microorganisms. More process-oriented research has identified best applicable reactor types and cultivation conditions. Techno-economic and life cycle analyses have identified key process bottlenecks with respect to economic feasibility and its environmental impact. The review has further identified current limitations and gaps in the knowledge, and also deliberates directions for future research and development of thermophilic biohydrogen production.

  1. Gold-catalyzed aerobic epoxidation of trans-stilbene in methylcyclohexane. Part II: Identification and quantification of a key reaction intermediate

    KAUST Repository

    Guillois, Kevin

    2013-03-01

    The gold-catalyzed aerobic oxidations of alkenes are thought to rely on the in situ synthesis of hydroperoxide species, which have however never been clearly identified. Here, we show direct experimental evidence for the presence of 1-methylcyclohexyl hydroperoxide in the aerobic co-oxidation of stilbene and methylcyclohexane catalyzed by the Au/SiO2-R972 optimized catalyst prepared in Part I. Determination of its response in gas chromatography, by triphenylphosphine titration followed by 31P NMR, allows to easily follow its concentration throughout the co-oxidation process and to clearly highlight the simultaneous existence of the methylcyclohexane autoxidation pathway and the stilbene epoxidation pathway. © 2012 Elsevier B.V. All rights reserved.

  2. Oscillations, period doublings, and chaos in CO oxidation and catalytic mufflers.

    Science.gov (United States)

    Marek, Milos; Schejbal, Matyás; Kocí, Petr; Nevoral, Vladislav; Kubícek, Milan; Hadac, Otto; Schreiber, Igor

    2006-09-01

    Early experimental observations of chaotic behavior arising via the period-doubling route for the CO catalytic oxidation both on Pt(110) and Ptgamma-Al(2)O(3) porous catalyst were reported more than 15 years ago. Recently, a detailed kinetic reaction scheme including over 20 reaction steps was proposed for the catalytic CO oxidation, NO(x) reduction, and hydrocarbon oxidation taking place in a three-way catalyst (TWC) converter, the most common reactor for detoxification of automobile exhaust gases. This reactor is typically operated with periodic variation of inlet oxygen concentration. For an unforced lumped model, we report results of the stoichiometric network analysis of a CO reaction subnetwork determining feedback loops, which cause the oscillations within certain regions of parameters in bifurcation diagrams constructed by numerical continuation techniques. For a forced system, numerical simulations of the CO oxidation reveal the existence of a period-doubling route to chaos. The dependence of the rotation number on the amplitude and period of forcing shows a typical bifurcation structure of Arnold tongues ordered according to Farey sequences, and positive Lyapunov exponents for sufficiently large forcing amplitudes indicate the presence of chaotic dynamics. Multiple periodic and aperiodic time courses of outlet concentrations were also found in simulations using the lumped model with the full TWC kinetics. Numerical solutions of the distributed model in two geometric coordinates with the CO oxidation subnetwork consisting of several tens of nonlinear partial differential equations show oscillations of the outlet reactor concentrations and, in the presence of forcing, multiple periodic and aperiodic oscillations. Spatiotemporal concentration patterns illustrate the complexity of processes within the reactor. PMID:17014241

  3. Parametric Investigation of Rate Enhancement during fast Temperature Cycling of CO Oxidation in Microreactors

    DEFF Research Database (Denmark)

    Jensen, Søren; Thorsteinsson, Sune; Hansen, Ole;

    2008-01-01

    A new microreactor that allows investigation of the effects of temperature oscillations at frequencies 10 times higher than in previous systems is presented. As an example, we investigate CO oxidation over a supported Pt catalyst subjected to a fast forced oscillation of the reactor temperature...... and confirm earlier findings of reaction rate enhancements. The enhancement is shown to increase at high frequencies. Varying the conversion and temperature oscillation amplitude is shown to have a large effect on the rate enhancement, and a large interaction between the two parameters is detected...

  4. Colored noise-enhanced intrinsic stochastic oscillations in CO oxidation on nanometer-sized Pd particles

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    How colored Gaussian noise (CN) affects the intrinsic stochastic oscillations (ISO) of CO oxidation on a nm-sized Pd particle is studied. It is found that the optimal ISO can be enhanced not only by a CN with appropriate noise intensity, but by a CN with appropriate correlation times. Moreover, the optimal ISO can be most greatly enhanced by the CN when the noise intensity or the correlation time is optimal. This result shows that external noise may, via its interplay with the internal noise of the system, play a constructive role in the ISO of the system, and the ISO can employ the external noise to reach a best oscillation performance.

  5. Canard explosion and internal signal stochastic bi-resonance in the CO oxidation on platinum surface

    Institute of Scientific and Technical Information of China (English)

    ZHAO; Gang; HOU; Zhonghuai

    2006-01-01

    Canard explosion is a kind of complex temporal behavior and is ubiquitous in excitable systems. It is associated with an abrupt change of amplitude and period of an oscillatory trajectory in a very narrow interval of a control parameter. We have analyzed in the present paper the behavior of canard explosion that is near a supercritical Hopf bifurcation and its response to white noise in a temporal model of CO oxidation on platinum surface. We have found that the presence of canard explosion gives rise to internal signal stochastic bi-resonance, thus demonstrating a novel functional feature of noise: selective amplifying signals with different periods.

  6. Nanoroses of nickel oxides: Synthesis, electron tomography study, and application in CO oxidation and energy storage

    KAUST Repository

    Fihri, Aziz

    2012-04-11

    Nickel oxide and mixed-metal oxide structures were fabricated by using microwave irradiation in pure water. The nickel oxide self-assembled into unique rose-shaped nanostructures. These nickel oxide roses were studied by performing electron tomography with virtual cross-sections through the particles to understand their morphology from their interior to their surface. These materials exhibited promising performance as nanocatalysts for CO oxidation and in energy storage devices. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Structure and reactivity of surface oxides on Pt(110) during catalytic CO oxidation

    OpenAIRE

    Ackermann, M. D.; Pedersen, T. M.; Hendriksen, B.L.M.; ROBACH, O.; Bobaru, S. C.; Quiros, C.; Kim, H.; Hammer, B; Ferrer Fàbregas, Salvador; Frenke, J. W. M.

    2005-01-01

    We present the first structure determination by surface x-ray diffraction during the restructuring of a model catalyst under reaction conditions, i.e., at high pressure and high temperature, and correlate the restructuring with a change in catalytic activity. We have analyzed the Pt(110) surface during CO oxidation at pressures up to 0.5 bar and temperatures up to 625 K. Depending on the O2/CO pressure ratio, we find three well-defined structures: namely, (i) the bulk-terminated Pt(110) surfa...

  8. Size Effect of Gold Sol/γ-Alumina on the Catalytic Activities of CO Oxidation

    Institute of Scientific and Technical Information of China (English)

    WANG Wei-Hua; GAO Geng-Yu

    2006-01-01

    The relationship between particle size and catalytic activity of gold nanoparticle catalysts with γ-Al2O3 as support has been investigated. The catalysts were prepared via the gold sol with different particle sizes by micelle method, and their structures were characterized by HRTEM and XRD, respectively. Furthermore, the catalytic activities were tested by CO oxidation. Experimental results showed that the catalytic activity became much weaker when gold particles were increased from 3.2 to 6.6 nm. Additionally, the particle size was also a key factor to govern catalytic activity with regard to gold supported on TiO2 prepared by the methods of deposition-precipitation.

  9. Acid-tolerant moderately thermophilic methanotrophs of the class Gammaproteobacteria isolated from tropical topsoil with methane seeps

    Directory of Open Access Journals (Sweden)

    Tajul eIslam

    2016-06-01

    Full Text Available Terrestrial tropical methane seep habitats are important ecosystems in the methane cycle. Methane oxidizing bacteria play a key role in these ecosystems as they reduce methane emissions to the atmosphere. Here we describe the isolation and initial characterization of two novel moderately thermophilic and acid-tolerant obligate methanotrophs, assigned BFH1 and BFH2 recovered from a tropical methane seep topsoil habitat. The new isolates were strictly aerobic, non-motile, coccus-shaped and utilized methane and methanol as sole carbon and energy source. Isolates grew at pH range 4.2–7.5 (optimal 5.5–6.0 and at a temperature range of 30–60oC (optimal 51–55oC. 16S rRNA gene phylogeny placed them in a well-separated branch forming a cluster together with the genus Methylocaldum as the closest relatives (93.1–94.1% sequence similarity. The genes pmoA, mxaF, and cbbL were detected, but mmoX was absent. Strains BFH1 and BFH2 are, to our knowledge, the first isolated acid-tolerant moderately thermophilic methane oxidizers of the class Gammaproteobacteria. Each strain probably denotes a novel species and they most likely represent a novel genus within the family Methylococcaceae of type I methanotrophs. Furthermore, the isolates increase our knowledge of acid-tolerant aerobic methanotrophs and signify a previously unrecognized biological methane sink in tropical ecosystems.

  10. Acid-Tolerant Moderately Thermophilic Methanotrophs of the Class Gammaproteobacteria Isolated From Tropical Topsoil with Methane Seeps

    Science.gov (United States)

    Islam, Tajul; Torsvik, Vigdis; Larsen, Øivind; Bodrossy, Levente; Øvreås, Lise; Birkeland, Nils-Kåre

    2016-01-01

    Terrestrial tropical methane seep habitats are important ecosystems in the methane cycle. Methane oxidizing bacteria play a key role in these ecosystems as they reduce methane emissions to the atmosphere. Here, we describe the isolation and initial characterization of two novel moderately thermophilic and acid-tolerant obligate methanotrophs, assigned BFH1 and BFH2 recovered from a tropical methane seep topsoil habitat. The new isolates were strictly aerobic, non-motile, coccus-shaped and utilized methane and methanol as sole carbon and energy source. Isolates grew at pH range 4.2–7.5 (optimal 5.5–6.0) and at a temperature range of 30–60°C (optimal 51–55°C). 16S rRNA gene phylogeny placed them in a well-separated branch forming a cluster together with the genus Methylocaldum as the closest relatives (93.1–94.1% sequence similarity). The genes pmoA, mxaF, and cbbL were detected, but mmoX was absent. Strains BFH1 and BFH2 are, to our knowledge, the first isolated acid-tolerant moderately thermophilic methane oxidizers of the class Gammaproteobacteria. Each strain probably denotes a novel species and they most likely represent a novel genus within the family Methylococcaceae of type I methanotrophs. Furthermore, the isolates increase our knowledge of acid-tolerant aerobic methanotrophs and signify a previously unrecognized biological methane sink in tropical ecosystems. PMID:27379029

  11. Acid-Tolerant Moderately Thermophilic Methanotrophs of the Class Gammaproteobacteria Isolated From Tropical Topsoil with Methane Seeps.

    Science.gov (United States)

    Islam, Tajul; Torsvik, Vigdis; Larsen, Øivind; Bodrossy, Levente; Øvreås, Lise; Birkeland, Nils-Kåre

    2016-01-01

    Terrestrial tropical methane seep habitats are important ecosystems in the methane cycle. Methane oxidizing bacteria play a key role in these ecosystems as they reduce methane emissions to the atmosphere. Here, we describe the isolation and initial characterization of two novel moderately thermophilic and acid-tolerant obligate methanotrophs, assigned BFH1 and BFH2 recovered from a tropical methane seep topsoil habitat. The new isolates were strictly aerobic, non-motile, coccus-shaped and utilized methane and methanol as sole carbon and energy source. Isolates grew at pH range 4.2-7.5 (optimal 5.5-6.0) and at a temperature range of 30-60°C (optimal 51-55°C). 16S rRNA gene phylogeny placed them in a well-separated branch forming a cluster together with the genus Methylocaldum as the closest relatives (93.1-94.1% sequence similarity). The genes pmoA, mxaF, and cbbL were detected, but mmoX was absent. Strains BFH1 and BFH2 are, to our knowledge, the first isolated acid-tolerant moderately thermophilic methane oxidizers of the class Gammaproteobacteria. Each strain probably denotes a novel species and they most likely represent a novel genus within the family Methylococcaceae of type I methanotrophs. Furthermore, the isolates increase our knowledge of acid-tolerant aerobic methanotrophs and signify a previously unrecognized biological methane sink in tropical ecosystems. PMID:27379029

  12. Thermophilic anaerobic waste water treatment, temperature aspects and process stability.

    NARCIS (Netherlands)

    Lier, van J.B.

    1995-01-01

    The main objective of this thesis was to assess the thermostability of thermophilic anaerobic wastewater treatment processes and the possibility to optimize the performance of thermophilic high-rate systems.Experiments were conducted to study the suitability of two types of seed material to start a

  13. Thermophillic Sidestream Anaerobic Membrane Bioreactors: The Shear Rate Dilemma

    NARCIS (Netherlands)

    Jeison, D.A.; Telkamp, P.; Lier, van J.B.

    2009-01-01

    Anaerobic biomass retention under thermophilic conditions has proven difficult. Membrane filtration can be used as alternative way to achieve high sludge concentrations. This research studied the feasibility of anaerobic membrane bioreactors (AnMBRs) under thermophilic conditions. A sidestream MBR w

  14. Thermophilic anaerobic digestion: the best option for waste treatment.

    Science.gov (United States)

    Suryawanshi, P C; Chaudhari, A B; Kothari, R M

    2010-03-01

    After introducing thermophilic anaerobic digestion (AD), characteristics of thermophilic methanogens are provided. Accordingly, (a) site of occurrence, (b) morphological characteristics (shape and motility), (c) biochemical characteristics (Gram character and % G+C profile), (d) nutritional characteristics (NaCl requirement and substrate specificity), and (e) growth characteristics (pH and temperature) of thermophilic methanogens are described. Some studies of the thermophilic AD are cited with their operational management problems. Subsequently, strategies to maximize net energy production are given, including mode of heating the bioreactors, role of agitation to promote AD performance and mode/intensity of mixing. Finally, advantages as well as drawbacks of AD under thermophilic conditions are given, concluding with its applications. PMID:20148754

  15. CO oxidation over ruthenium: identification of the catalytically active phases at near-atmospheric pressures

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Feng; Goodman, Wayne D.

    2012-05-21

    CO oxidation was carried out over Ru(0001) and RuO2(110) thin film grown on Ru(0001) at various O2/CO ratios near atmospheric pressures. Reaction kinetics, coupled with in situ polarization modulation infrared reflection absorption spectroscopy (PM-IRAS) and post-reaction Auger electron spectroscopy (AES) measurements were used to identify the catalytically relevant phases at different reaction conditions. Under stoichiometric and reducing conditions at all reaction temperatures, as well as net-oxidizing reaction conditions below {approx}475 K, a reduced metallic phase with chemisorbed oxygen is the thermodynamically stable and catalytically active phase. On this surface CO oxidation occurs at surface defect sites, for example step edges. Only at net-oxidizing reaction conditions and above {approx}475 K is the RuO2 thin film grown on metallic Ru stable and active. However, RuO2 is not active itself without the existence of the metal substrate, suggesting the importance of a strong metal-substrate interaction (SMSI).

  16. Theoretical study of the catalytic CO oxidation by Pt catalyst supported on Ge-doped grapheme.

    Science.gov (United States)

    Tang, Yanan; Yang, Zongxian; Dai, Xianqi; Lu, Zhansheng; Zhang, Yanxing; Fu, Zhaoming

    2014-09-01

    The geometry, electronic structure and catalytic properties of the anchored Pt atom on the Ge-doped graphene (Pt/Ge-graphene) substrates are investigated using the first-principles computations. It is found that Ge atoms can form strong covalent bonds with the carbon atoms at the vacancy site on the defective graphene. The Ge-graphene as substrate can effectively anchored Pt atoms and form supported Pt catalyst, which exhibits good catalytic activity for CO oxidation with a two-step route, starting with the Langmuir-Hinshelwood (LH) reaction followed by the Eley-Rideal (ER) reaction. The Ge dopant in graphene plays a vital role in enhancing the substrate-adsorbate interaction through facilitating the charge redistribution at their interfaces. The Ge-graphene can be used as the reactive support to control the stability and activity of the Pt catalysts. This work provides valuable guidance on fabricating carbon-based catalysts for CO oxidation, and validates the reactivity of single-atom catalyst for designing atomic-scale catalysts.

  17. Gold-TiO2-Nickel catalysts for low temperature-driven CO oxidation reaction

    Science.gov (United States)

    Hinojosa-Reyes, Mariana; Zanella, Rodolfo; Maturano-Rojas, Viridiana; Rodríguez-González, Vicente

    2016-04-01

    Nickel-doped-TiO2 catalysts were prepared by the sol-gel method and surface modified with gold nanoparticles (AuNPs) by the urea-deposition-precipitation technique. The as-synthesized catalysts were characterized by X-ray diffraction, Raman and XPS spectroscopies, N2 physisorption, STEM-HAADF microscopy and TPR hydrogen consumption. The Au/TiO2-Ni catalysts were evaluated catalytically performing CO oxidation reactions. The catalyst with nickel content of 1 wt. % (Au/TiO2-Ni 1) showed the highest CO conversion with respect to the high-nickel-content or bare/commercial TiO2 at 0 °C. In situ DRIFTS showed a strong participation of both nickel due to the presence of surface-nickel-metallic nanoparticles formed during the CO adsorption process at reaction temperatures above 200 °C, and surface-bridged-nickel-CO species. A minor deactivation rate was observed for the Au/TiO2-Ni 1 catalyst in comparison with the Au/TiO2 one. The oxygen vacancies that were created on the sol-gel-doped TiO2 improved the catalytic behavior during the performance of CO oxidation reactions, and inhibited the AuNP sintering.

  18. Insights into the dominant factors of porous gold for CO oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Kameoka, Satoshi, E-mail: kameoka@tagen.tohoku.ac.jp; Miyamoto, Kanji [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Tanabe, Toyokazu [Kanagawa University, Yokohama 221-8686 (Japan); Tsai, An Pang [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); National Institute of Materials Science (NIMS), Tsukuba 305-0047 (Japan)

    2016-01-21

    Three different porous Au catalysts that exhibit high catalytic activity for CO oxidation were prepared by the leaching of Al from an intermetallic compound, Al{sub 2}Au, with 10 wt. %-NaOH, HNO{sub 3}, or HCl aqueous solutions. The catalysts were investigated using Brunauer-Emmett-Teller measurements, synchrotron X-ray powder diffraction, hard X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and transmission electron microscopy (TEM). Broad diffraction peaks generated during the leaching process correlated with high activity for all the porous Au catalysts. CO oxidation catalyzed by porous Au leached with NaOH and HNO{sub 3} is considered to be dominated by different mechanisms at low (< 320 K) and high (> 370 K) temperatures. Activity in the low-temperature region is mainly attributed to the perimeter interface between residual Al species (AlO{sub x}) and porous Au, whereas activity in the high-temperature region results from a high density of lattice defects such as twins and dislocations, which were evident from diffraction peak broadening and were observed with high-resolution TEM in the porous Au leached with NaOH. It is proposed that atoms located at lattice defects on the surfaces of porous Au are the active sites for catalytic reactions.

  19. Synthesis of Catalysts and Its Application for Low-Temperature CO Oxidation

    Directory of Open Access Journals (Sweden)

    Der-Shing Lee

    2013-01-01

    Full Text Available A series of Au/-TiO2 with various Co/Ti ratios prepared. /TiO2 was prepared by incipient wetness impregnation with aqueous solution of cobalt nitrate. Au catalysts were prepared by deposition-precipitation (DP method at pH 7 and 338 K. The catalysts were characterized by inductively coupled plasma-mass spectrometry, temperature programming reduction, X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. The reaction was carried out in a fixed bed reactor with a feed containing 1% CO in air at weight hourly space velocities of 120,000 mL/h g and 180,000 mL/h g. High gold dispersion and narrow particle size distribution were obtained by DP method. The addition of into Au/TiO2 enhanced the activity of CO oxidation significantly. Au/5%  -TiO2 had the highest catalyst among all the catalysts. was mainly in the form of nanosize Co3O4 which could stabilize the Au nanoparticles. donated partial electrons to Au. The interactions among Au, , and TiO2 account for the high catalytic activity for CO oxidation.

  20. Time resolved FTIR study of the catalytic CO oxidation under periodic variation of the reactant concentration

    Energy Technology Data Exchange (ETDEWEB)

    Kritzenberger, J.; Wokaun, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    Oxidation of CO over palladium/zirconia catalyst obtained from an amorphous Pd{sub 25}Zr{sub 75} precursor was investigated by time resolved FTIR spectroscopy. Sine wave shaped modulation of the reactant concentration, i.e. variation of CO or O{sub 2} partial pressure, was used to induce variations of the IR signals of product (CO{sub 2}) and unconverted reactant (CO), which were detected in a multi-pass absorption cell. The phase shift {phi} between external perturbation and variation of the CO{sub 2} signal was examined in dependence on temperature (100{sup o}C{<=}T{<=}350{sup o}C) and modulation frequency (1.39x10{sup -4}Hz{<=}{omega}{<=}6.67x10{sup -2}Hz). From the phase shift values, a simple Eley-Rideal mechanism is excluded, and the rate limiting step of the Langmuir-Hinshelwood mechanism for the CO oxidation may be identified. Adsorption and possible surface movement of CO to the actual reaction site determine the rate of the CO oxidation on the palladium/zirconia catalyst used in our study. The introduction of an external perturbation is a first step towards the application of two-dimensional infrared spectroscopy to heterogeneous catalyzed reactions. (author) 3 figs., 4 refs.

  1. Thermophilic fermentation of acetoin and 2,3-butanediol by a novel Geobacillus strain

    Directory of Open Access Journals (Sweden)

    Xiao Zijun

    2012-12-01

    Full Text Available Abstract Background Acetoin and 2,3-butanediol are two important biorefinery platform chemicals. They are currently fermented below 40°C using mesophilic strains, but the processes often suffer from bacterial contamination. Results This work reports the isolation and identification of a novel aerobic Geobacillus strain XT15 capable of producing both of these chemicals under elevated temperatures, thus reducing the risk of bacterial contamination. The optimum growth temperature was found to be between 45 and 55°C and the medium initial pH to be 8.0. In addition to glucose, galactose, mannitol, arabionose, and xylose were all acceptable substrates, enabling the potential use of cellulosic biomass as the feedstock. XT15 preferred organic nitrogen sources including corn steep liquor powder, a cheap by-product from corn wet-milling. At 55°C, 7.7 g/L of acetoin and 14.5 g/L of 2,3-butanediol could be obtained using corn steep liquor powder as a nitrogen source. Thirteen volatile products from the cultivation broth of XT15 were identified by gas chromatography–mass spectrometry. Acetoin, 2,3-butanediol, and their derivatives including a novel metabolite 2,3-dihydroxy-3-methylheptan-4-one, accounted for a total of about 96% of all the volatile products. In contrast, organic acids and other products were minor by-products. α-Acetolactate decarboxylase and acetoin:2,6-dichlorophenolindophenol oxidoreductase in XT15, the two key enzymes in acetoin metabolic pathway, were found to be both moderately thermophilic with the identical optimum temperature of 45°C. Conclusions Geobacillus sp. XT15 is the first naturally occurring thermophile excreting acetoin and/or 2,3-butanediol. This work has demonstrated the attractive prospect of developing it as an industrial strain in the thermophilic fermentation of acetoin and 2,3-butanediol with improved anti-contamination performance. The novel metabolites and enzymes identified in XT15 also indicated its

  2. Chemisorption of CO and Mechanism of CO Oxidation on Supported Platinum Nanoclusters

    Energy Technology Data Exchange (ETDEWEB)

    Allian, Ayman D.; Takanabe, Kazuhiro; Fujdala, Kyle L.; Hao, Xianghong; Truex, Timothy J.; Cai, Juan; Buda, Corneliu; Neurock, Matthew; Iglesia, Enrique

    2011-03-30

    Kinetic, isotopic, and infrared studies on well-defined dispersed Pt clusters are combined here with first-principle theoretical methods on model cluster surfaces to probe the mechanism and structural requirements for CO oxidation catalysis at conditions typical of its industrial practice. CO oxidation turnover rates and the dynamics and thermodynamics of adsorption-desorption processes on cluster surfaces saturated with chemisorbed CO were measured on 1-20 nm Pt clusters under conditions of strict kinetic control. Turnover rates are proportional to O2 pressure and inversely proportional to CO pressure, consistent with kinetically relevant irreversible O2 activation steps on vacant sites present within saturated CO monolayers. These conclusions are consistent with the lack of isotopic scrambling in C16O-18O2-16O2 reactions, and with infrared bands for chemisorbed CO that did not change within a CO pressure range that strongly influenced CO oxidation turnover rates. Density functional theory estimates of rate and equilibrium constants show that the kinetically relevantO2 activation steps involve directO2* (or O2) reactions with CO* to form reactive O*-O-C*dO intermediates that decompose to form CO2 and chemisorbed O*, instead of unassisted activation steps involving molecular adsorption and subsequent dissociation of O2. These CO-assisted O2 dissociation pathways avoid the higher barriers imposed by the spin-forbidden transitions required for unassistedO2 dissociation on surfaces saturated with chemisorbed CO. Measured rate parameters for CO oxidation were independent of Pt cluster size; these parameters depend on the ratio of rate constants for O2 reactions with CO* and CO adsorption equilibrium constants, which reflect the respective activation barriers and reaction enthalpies for these two steps. Infrared spectra during isotopic displacement and thermal desorption with 12CO-13CO mixtures showed that the binding, dynamics, and thermodynamics of CO chemisorbed at

  3. Chemisorption of CO and mechanism of CO oxidation on supported platinum nanoclusters

    KAUST Repository

    Allian, Ayman Daoud

    2011-03-30

    Kinetic, isotopic, and infrared studies on well-defined dispersed Pt clusters are combined here with first-principle theoretical methods on model cluster surfaces to probe the mechanism and structural requirements for CO oxidation catalysis at conditions typical of its industrial practice. CO oxidation turnover rates and the dynamics and thermodynamics of adsorption-desorption processes on cluster surfaces saturated with chemisorbed CO were measured on 1-20 nm Pt clusters under conditions of strict kinetic control. Turnover rates are proportional to O2 pressure and inversely proportional to CO pressure, consistent with kinetically relevant irreversible O2 activation steps on vacant sites present within saturated CO monolayers. These conclusions are consistent with the lack of isotopic scrambling in C16O-18O2-16O 2 reactions, and with infrared bands for chemisorbed CO that did not change within a CO pressure range that strongly influenced CO oxidation turnover rates. Density functional theory estimates of rate and equilibrium constants show that the kinetically relevant O2 activation steps involve direct O2* (or O2) reactions with CO* to form reactive O*-O-C*=O intermediates that decompose to form CO 2 and chemisorbed O*, instead of unassisted activation steps involving molecular adsorption and subsequent dissociation of O2. These CO-assisted O2 dissociation pathways avoid the higher barriers imposed by the spin-forbidden transitions required for unassisted O2 dissociation on surfaces saturated with chemisorbed CO. Measured rate parameters for CO oxidation were independent of Pt cluster size; these parameters depend on the ratio of rate constants for O2 reactions with CO* and CO adsorption equilibrium constants, which reflect the respective activation barriers and reaction enthalpies for these two steps. Infrared spectra during isotopic displacement and thermal desorption with 12CO- 13CO mixtures showed that the binding, dynamics, and thermodynamics of CO

  4. Annular purpura and step aerobics.

    Science.gov (United States)

    Allan, S J; Humphreys, F; Buxton, P K

    1994-09-01

    Step aerobic classes are at present one of the most popular forms of exercise undertaken by young adults. To date no dermatological abnormalities have been described in people regularly performing step aerobics. We describe a case in which a healthy young woman developed an extensive pigmented purpuric eruption 4 weeks after commencing regular step aerobic classes. The eruption resolved completely 8 weeks after regular exercise was ceased. PMID:7955503

  5. Bio-hydrogen production in an EGSB reactor under mesophilic, thermophilic and hyperthermophilic conditions

    OpenAIRE

    Abreu, A. A.; Danko, Anthony S.; Alves, M. M.

    2007-01-01

    Mesophilic, thermophilic and hyperthermophilic bio-hydrogen production with an expanded granular sludge blanket (EGSB) fed with glucose and arabinose, without methane production, was demonstrated. Homoacetogenesis was observed on reactor when operated under mesophilic (37ºC) conditions but not under thermophilic (55ºC) and hyper-thermophilic conditions (70ºC). It was also found that under thermophilic and hyper-thermophilic conditions glucose is preferentially consumed than ara...

  6. Aerobic landfill bioreactor

    Science.gov (United States)

    Hudgins, Mark P; Bessette, Bernard J; March, John; McComb, Scott T.

    2000-01-01

    The present invention includes a method of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120.degree. F. and 140.degree. F. in steady state.

  7. Deactivation of selected noble metal catalysts during CO oxidation: An in-situ IR and kinetic study

    International Nuclear Information System (INIS)

    The deactivation of the oxidation of CO over supported Rh, Ru and Pd as a function of the reactant gas composition is discussed. On supported Rh we have found that the rate of CO oxidation is strongly dependent on the oxidation state of the metal. The rate of CO oxidation over supported Ru is strongly inhibited by the incorporation of sub-surface O2. The oxidation of CO on supported Pd is inhibited by the formation of PdO under conditions in which the CO/O2 reactant gas ratio is net oxidizing and by enhanced CO surface coverage following ignition when the reactant gas ratio is net reducing

  8. Comparison of the thermostability of cellulases from various thermophilic fungi

    Energy Technology Data Exchange (ETDEWEB)

    Wojtczak, G.; Breuil, C.; Yamada, J.; Saddler, J.N.

    1987-10-01

    The cellulase activities of six thermophilic fungi were compared. Although the thermophilic fungi grew at relatively high temperatures (> 45/sup 0/C) the optimum temperatures for assaying the various cellulase activities were only slightly higher than the optimum temperatures for the mesophilic fungi, Trichoderma harzianum. Over prolonged incubation (> 24 h) the thermophilic strains demonstrated a higher hydrolytic potential as a result of the greater thermostability of the cellulase components. Although the extracellular cellulase activities had similar pH and temperature optima, in some cases the thermostability of the extracellular components were considerably lower.

  9. Internal noise stochastic resonance in CO oxidation on nm-sized palladium particles

    Institute of Scientific and Technical Information of China (English)

    GONG Yubing; HOU Zhonghuai; XIN Houwen

    2005-01-01

    Based on a stochastic mesoscopic model, the influence of internal noise on the oscillatory kinetics of the catalytic oxidation of CO on nm-sized palladium particles is studied, using the chemical Langevin equations, Poisson approximation algorithm, and exact stochastic simulation algorithm. The reaction rate oscillations are of stochastic nature due to considerable internal noise in such mesoscopic systems. It is found that the performance of the stochastic oscillations undergoes a maximum with the variation of internal noise level for a given CO partial pressure, which demonstrates the occurrence of internal noise stochastic resonance. This phenomenon implies that optimal internal noise would favor the reaction rate oscillation of CO oxidation on nm particles. Such a phenomenon is robust to the change of external parameters, such as CO pressures.

  10. Gold nanocatalysts supported on heterostructured PbSO4-MCF mesoporous materials for CO oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lin [South Central Univ Nationalities China; Tian, Chengcheng [ORNL; Chai, Songhai [ORNL; Binder, Andrew J [ORNL; Brown, Suree [ORNL; Veith, Gabriel M [ORNL; Dai, Sheng [ORNL

    2014-01-01

    Metal oxides are commonly used as the supports of gold nanoparticles for catalytic CO oxidation, whereas metal salts are rarely considered suitable supports. In the present work, we developed a new kind of gold nanocatalyst supported on heterostructured PbSO4-MCF mesoporous materials that was prepared by an in situ growth method using dodecylbenzenesulfonate (SOBS) as a sulfonate precursor. It was found that an Au/PbSO4-MCF (SDBS) catalyst preheated at 300 degrees C showed high CO conversion below 100 degrees C. In addition, the stability of selected catalysts was studied as a function of time on stream. Because of the alteration of surface properties, these Au nanocatalysts were highly sinter-resistant. Published by Elsevier B.V.

  11. CeO2-Co3O4 Catalysts for CO Oxidation

    Institute of Scientific and Technical Information of China (English)

    Xu Xiuyan; Li Jinjun; Hao Zhengping

    2006-01-01

    CeO2-Co3O4 catalysts for low-temperature CO oxidation were prepared by a co-precipitation method.In combination with the characterization methods of N2 adsorption/desorption, XRD, temperature-programmed reduction (TPR), and FT-IR, the influence of the cerium content on the catalytic performance of CeO2-Co3O4 was investigated.The results indicate that the prepared CeO2-Co3O4 catalysts exhibit a better activity than that of pure CeO2 or pure Co3O4.The catalyst with the Ce/Co atomic ratio 1:16 exhibits the best activity, which converts 77% of CO at room temperature and completely oxidizes CO at 45 ℃.

  12. Graphene supported nano particles of Pt-Ni for CO oxidation

    Science.gov (United States)

    Zhang, Cheng; Lv, Wei; Yang, Quanhong; Liu, Yuan

    2012-08-01

    In this study, a series of graphene supported Pt, Ni and Pt-Ni nano particles were successfully synthesized by a simple impregnation method. The resultant composites were characterized using SEM, XRD, HRTEM, XPS and TPR techniques and their catalytic performance for the oxidation of carbon monoxide was tested. It was shown that in the prepared metal/graphene composite, metal particles were highly dispersed on the graphene sheets (GS) with an average particle size of 1-3 nm. The results of catalytic performance tests indicate that the activity decreases in the order of Pt-Ni/GS, Pt/GS and Ni/GS. In the sample of Pt-Ni/GS, Pt-Ni alloy was formed, which contributed to the high activity of Pt-Ni/GS for CO oxidation.

  13. Forced bursting and transition mechanism in CO oxidation with three time scales

    Institute of Scientific and Technical Information of China (English)

    Li Xiang-Hong; Bi Qin-Sheng

    2013-01-01

    The mathematical model of CO oxidation with three time scales on platinum group metals is investigated,in which order gaps between the time scales related to external perturbation and the rates associated with different chemical reaction steps exist.Forced bursters,such as point-point type forced bursting and point-cycle type forced bursting,are presented.The bifurcation mechanism of forced bursting is novel,and the phenomenon where two different kinds of spiking states coexist in point-cycle type forced bursting has not been reported in previous work.A double-parameter bifurcation set of the fast subsystem is explored to reveal the transition mechanisms of different forced bursters with parameter variation.

  14. Synthesis of porous hematite nanorods loaded with CuO nanocrystals as catalysts for CO oxidation

    Institute of Scientific and Technical Information of China (English)

    Jianliang Cao; Yan Wang; Tianyi Ma; Yuping Liu; Zhongyong Yuan

    2011-01-01

    Porous hematite (α-Fe2O3) nanorods with the diameter of 20-40 nm and the length of 80-300 nm were synthesized by a simple surfactantassisted method in the presence of cetyltrimethylammonium bromide (CTAB).The α-Fe2O3 nanorods possess a mesostructure with a pore size distribution in the range of 5-12 nm and high surface area,exhibiting high catalytic activity for CO oxidation.CuO nanocrystals were loaded on the surface of porous α-Fe2O3 nanorods by a deposition-precipitation method,and the catalysts exhibited superior activity for catalytic oxidation of CO,as compared with commercial α-Fe2O3 powders supported CuO catalyst.The enhanced catalytic activity was attributed to the strong interaction between the CuO nanocrystals and the support of porous α-Fe2O3 nanorods.

  15. Colored noise-enhanced intrinsic stochastic oscillations in CO oxidation on nanometer-sized Pd particles

    Institute of Scientific and Technical Information of China (English)

    XIE YanHang; GONG YuBing; XU Bo; SUN FuWen

    2009-01-01

    How colored Gaussian noise (CN) affects the intrinsic stochastic oscillations (ISO) of CO oxidation on a nm-sized Pd particle is studied.It is found that the optimal ISO can be enhanced not only by a CN with appropriate noise intensity,but by a CN with appropriate correlation times.Moreover,the optimal ISO can be most greatly enhanced by the CN when the noise intensity or the correlation time is optimal.This result shows that external noise may,via its interplay with the internal noise of the system,play a constructive role in the ISO of the system,and the ISO can employ the external noise to reach a best oscillation performance.

  16. Activity and deactivation behavior of Au/LaMnO3 catalysts for CO oxidation

    Institute of Scientific and Technical Information of China (English)

    JIA Meilin; LI Xu; Zhaorigetu; SHEN Yuenian; LI Yunxia

    2011-01-01

    Perovskite oxide LaMnO3 was prepared by sol-gel method and the nanosize Au/LaMnO3 catalyst was prepared by deposition- precipitation (DP) method in the paper. Characterization of the catalyst sample was made by X-ray diffractometer (XRD), atom absorption spectra (AAS) and X-ray photoelectron spectroscopy (XPS) instrumental methods. The activity, long-term stability and the reasons for deactivation of the gold catalyst in CO oxidation were investigated. The experiment results demonstrated that the Au/LaMnO3 catalyst exhibited high stability in the ambient storage process. However, the gradual decrease in initial activity during 100 h reaction was still observed, which could be ascribed to the aggregation of gold particles and the transfer from gold ion to the metal gold.

  17. Catalytic Behaviour of Mesoporous Cobalt-Aluminum Oxides for CO Oxidation

    Directory of Open Access Journals (Sweden)

    Ankur Bordoloi

    2014-01-01

    Full Text Available Ordered mesoporous materials are promising catalyst supports due to their uniform pore size distribution, high specific surface area and pore volume, tunable pore sizes, and long-range ordering of the pore packing. The evaporation-induced self-assembly (EISA process was applied to synthesize mesoporous mixed oxides, which consist of cobalt ions highly dispersed in an alumina matrix. The characterization of the mesoporous mixed cobalt-aluminum oxides with cobalt loadings in the range from 5 to 15 wt% and calcination temperatures of 673, 973, and 1073 K indicates that Co2+ is homogeneously distributed in the mesoporous alumina matrix. As a function of the Co loading, different phases are present comprising poorly crystalline alumina and mixed cobalt aluminum oxides of the spinel type. The mixed cobalt-aluminum oxides were applied as catalysts in CO oxidation and turned out to be highly active.

  18. Probing the transition state region in catalytic CO oxidation on Ru

    Energy Technology Data Exchange (ETDEWEB)

    Ostrom, H. [Stockholm Univ. (Sweden); Oberg, H. [Stockholm Univ. (Sweden); Xin, H. [SLAC National Accelerator Lab., Menlo Park, CA (United States); LaRue, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States); Beye, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Helmholtz Zentrum Berlin fur Materialien und Energie GmbH, Berlin (Germany); Dell' Angela, M. [Univ. of Hamburg and Center for Free Electron Laser Science, Hamburg (Germany); Gladh, J. [Stockholm Univ. (Sweden); Ng, M. L. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Sellberg, J. A. [Stockholm Univ. (Sweden); SLAC National Accelerator Lab., Menlo Park, CA (United States); Kaya, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Mercurio, G. [Univ. of Hamburg and Center for Free Electron Laser Science, Hamburg (Germany); Nordlund, D. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Hantschmann, M. [Helmholtz Zentrum Berlin fur Materialien und Energie GmbH, Berlin (Germany); Hieke, F. [Univ. of Hamburg and Center for Free Electron Laser Science, Hamburg (Germany); Kuhn, D. [Helmholtz Zentrum Berlin fur Materialien und Energie GmbH, Berlin (Germany); Schlotter, W. F. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Dakovski, G. L. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Turner, J. J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Minitti, M. P. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Mitra, A. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Moeller, S. P. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Fohlisch, A. [Helmholtz Zentrum Berlin fur Materialien und Energie GmbH, Berlin (Germany); Univ. Potsdam, Potsdam (Germany); Wolf, M. [Fritz-Haber Institute of the Max-Planck-Society, Berlin (Germany); Wurth, W. [Univ. of Hamburg and Center for Free Electron Laser Science, Hamburg (Germany); DESY Photon Science, Hamburg (Germany); Persson, M. [The Univ. of Liverpool, Liverpool (United Kingdom); Norskov, J. K. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States); Abild-Pedersen, F. [Stanford Univ., Stanford, CA (United States); Ogasawara, H. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Pettersson, L. G. M. [Stockholm Univ. (Sweden); Nilsson, A. [Stockholm Univ. (Sweden); SLAC National Accelerator Lab., Menlo Park, CA (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-02-12

    Femtosecond x-ray laser pulses are used to probe the CO oxidation reaction on ruthenium (Ru) initiated by an optical laser pulse. On a time scale of a few hundred femtoseconds, the optical laser pulse excites motions of CO and O on the surface, allowing the reactants to collide, and, with a transient close to a picosecond (ps), new electronic states appear in the O K-edge x-ray absorption spectrum. Density functional theory calculations indicate that these result from changes in the adsorption site and bond formation between CO and O with a distribution of OC–O bond lengths close to the transition state (TS). After 1 ps, 10% of the CO populate the TS region, which is consistent with predictions based on a quantum oscillator model.

  19. Thermophilic Sulfate-Reducing Bacteria in Cold Marine Sediment

    DEFF Research Database (Denmark)

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

    1994-01-01

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

  20. Global Association between Thermophilicity and Vancomycin Susceptibility in Bacteria.

    Science.gov (United States)

    Roy, Chayan; Alam, Masrure; Mandal, Subhrangshu; Haldar, Prabir K; Bhattacharya, Sabyasachi; Mukherjee, Trinetra; Roy, Rimi; Rameez, Moidu J; Misra, Anup K; Chakraborty, Ranadhir; Nanda, Ashish K; Mukhopadhyay, Subhra K; Ghosh, Wriddhiman

    2016-01-01

    Exploration of the aquatic microbiota of several circum-neutral (6.0-8.5 pH) mid-temperature (55-85°C) springs revealed rich diversities of phylogenetic relatives of mesophilic bacteria, which surpassed the diversity of the truly-thermophilic taxa. To gain insight into the potentially-thermophilic adaptations of the phylogenetic relatives of Gram-negative mesophilic bacteria detected in culture-independent investigations we attempted pure-culture isolation by supplementing the enrichment media with 50 μg ml(-1) vancomycin. Surprisingly, this Gram-positive-specific antibiotic eliminated the entire culturable-diversity of chemoorganotrophic and sulfur-chemolithotrophic bacteria present in the tested hot water inocula. Moreover, it also killed all the Gram-negative hot-spring isolates that were obtained in vancomycin-free media. Concurrent literature search for the description of Gram-negative thermophilic bacteria revealed that at least 16 of them were reportedly vancomycin-susceptible. While these data suggested that vancomycin-susceptibility could be a global trait of thermophilic bacteria (irrespective of their taxonomy, biogeography and Gram-character), MALDI Mass Spectroscopy of the peptidoglycans of a few Gram-negative thermophilic bacteria revealed that tandem alanines were present in the fourth and fifth positions of their muropeptide precursors (MPPs). Subsequent phylogenetic analyses revealed a close affinity between the D-alanine-D-alanine ligases (Ddl) of taxonomically-diverse Gram-negative thermophiles and the thermostable Ddl protein of Thermotoga maritima, which is well-known for its high specificity for alanine over other amino acids. The Ddl tree further illustrated a divergence between the homologs of Gram-negative thermophiles and mesophiles, which broadly coincided with vancomycin-susceptibility and vancomycin-resistance respectively. It was thus hypothesized that thermophilic Ddls have been evolutionarily selected to favor a D-ala-D-ala bonding

  1. Global association between thermophilicity and vancomycin susceptibility in bacteria

    Directory of Open Access Journals (Sweden)

    Chayan eRoy

    2016-03-01

    Full Text Available Exploration of the aquatic microbiota of several circum-neutral (6.0-8.5 pH mid-temperature (55-85 OC springs revealed rich diversities of phylogenetic relatives of mesophilic bacteria, which surpassed the diversity of the truly-thermophilic taxa. To gain insight into the potentially-thermophilic adaptations of the phylogenetic relatives of Gram-negative mesophilic bacteria detected in culture-independent investigations we attempted pure-culture isolation by supplementing the enrichment media with 50 µg ml-1 vancomycin. Surprisingly, this Gram-positive-specific antibiotic eliminated the entire culturable-diversity of chemoorganotrophic and sulfur-chemolithotrophic bacteria present in the tested hot water inocula. Moreover, it also killed all the Gram-negative hot-spring isolates that were obtained in vancomycin-free media. Concurrent literature search for the description of Gram-negative thermophilic bacteria revealed that at least 16 of them were reportedly vancomycin-susceptible. While these data suggested that vancomycin-susceptibility could be a global trait of thermophilic bacteria (irrespective of their taxonomy, biogeography and Gram-character, MALDI Mass Spectroscopy of the peptidoglycans of a few Gram-negative thermophilic bacteria revealed that tandem alanines were present in the fourth and fifth positions of their muropeptide precursors (MPPs. Subsequent phylogenetic analyses revealed a close affinity between the D-alanine-D-alanine ligases (Ddl of taxonomically-diverse Gram-negative thermophiles and the thermostable Ddl protein of Thermotoga maritima, which is well-known for its high specificity for alanine over other amino acids. The Ddl tree further illustrated a divergence between the homologs of Gram-negative thermophiles and mesophiles, which broadly coincided with vancomycin-susceptibility and vancomycin-resistance respectively. It was thus hypothesized that thermophilic Ddls have been evolutionarily selected to favor a D

  2. Optimization of preparation conditions of Fe-Co nanoparticles in low-temperature CO oxidation reaction by taguchi design method

    Institute of Scientific and Technical Information of China (English)

    Abolfazl Biabani; Mehran Rezaei; Zohreh Fattah

    2012-01-01

    Mixed iron-cobalt oxide (Co/Fe molar ratio=1/5) are prepared using a simple co-precipitation procedure and studied for the catalytic oxidation of carbon monoxide.In particular,the effects of a range of preparation variables such as pH value when precipitation,aging temperature,precipitation agent type and aging time are investigated on the catalytic performance of synthesized Fe-Co oxides in CO oxidation reaction.In addition,the preparation factors were optimized by Taguchi design method.The optimized sample was characterized by XRD,N2 adsorption/desorption,TEM and TGA/DTA techniques.The results reveal that the optimized sample shows a mesoporous structure with a narrow pore size distribution centered in the range of 2-7 nm.The sample prepared under optimized conditions has high activity and stability toward removal of carbon monoxide at lower temperatures.It is shown that different preparation variables influence the catalytic performance of Fe-Co oxide in CO oxidation reaction.

  3. Indication of non-thermal contribution to visible femtosecond laser-induced CO oxidation on Ru(0001)

    International Nuclear Information System (INIS)

    We studied CO oxidation on Ru(0001) induced by 400 nm and 800 nm femtosecond laser pulses where we find a branching ratio between CO oxidation and desorption of 1:9 and 1:31, respectively, showing higher selectivity towards CO oxidation for the shorter wavelength excitation. Activation energies computed with density functional theory show discrepancies with values extracted from the experiments, indicating both a mixture between different adsorbed phases and importance of non-adiabatic effects on the effective barrier for oxidation. We simulated the reactions using kinetic modeling based on the two-temperature model of laser-induced energy transfer in the substrate combined with a friction model for the coupling to adsorbate vibrations. This model gives an overall good agreement with experiment except for the substantial difference in yield ratio between CO oxidation and desorption at 400 nm and 800 nm. However, including also the initial, non-thermal effect of electrons transiently excited into antibonding states of the O-Ru bond yielded good agreement with all experimental results

  4. Indication of non-thermal contribution to visible femtosecond laser-induced CO oxidation on Ru(0001)

    Energy Technology Data Exchange (ETDEWEB)

    Öberg, H.; Gladh, J.; Marks, K.; Pettersson, L. G. M.; Öström, H., E-mail: ostrom@fysik.su.se [Department of Physics, AlbaNova University Center, Stockholm University, SE-10691 Stockholm (Sweden); Ogasawara, H. [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Nilsson, A. [Department of Physics, AlbaNova University Center, Stockholm University, SE-10691 Stockholm (Sweden); SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States)

    2015-08-21

    We studied CO oxidation on Ru(0001) induced by 400 nm and 800 nm femtosecond laser pulses where we find a branching ratio between CO oxidation and desorption of 1:9 and 1:31, respectively, showing higher selectivity towards CO oxidation for the shorter wavelength excitation. Activation energies computed with density functional theory show discrepancies with values extracted from the experiments, indicating both a mixture between different adsorbed phases and importance of non-adiabatic effects on the effective barrier for oxidation. We simulated the reactions using kinetic modeling based on the two-temperature model of laser-induced energy transfer in the substrate combined with a friction model for the coupling to adsorbate vibrations. This model gives an overall good agreement with experiment except for the substantial difference in yield ratio between CO oxidation and desorption at 400 nm and 800 nm. However, including also the initial, non-thermal effect of electrons transiently excited into antibonding states of the O-Ru bond yielded good agreement with all experimental results.

  5. Performance of mesophilic biohydrogen-producing cultures at thermophilic conditions.

    Science.gov (United States)

    Gupta, Medhavi; Gomez-Flores, Maritza; Nasr, Noha; Elbeshbishy, Elsayed; Hafez, Hisham; Hesham El Naggar, M; Nakhla, George

    2015-09-01

    In this study, batch tests were conducted to investigate the performance of mesophilic anaerobic digester sludge (ADS) at thermophilic conditions and estimate kinetic parameters for co-substrate fermentation. Starch and cellulose were used as mono-substrate and in combination as co-substrates (1:1 mass ratio) to conduct a comparative assessment between mesophilic (37 °C) and thermophilic (60 °C) biohydrogen production. Unacclimatized mesophilic ADS responded well to the temperature change. The highest hydrogen yield of 1.13 mol H2/mol hexose was observed in starch-only batches at thermophilic conditions. The thermophilic cellulose-only yield (0.42 mol H2/mol hexose) was three times the mesophilic yield (0.13 mol H2/mol hexose). Interestingly, co-fermentation of starch-cellulose at mesophilic conditions enhanced the hydrogen yield by 26% with respect to estimated mono-substrate yields, while under thermophilic conditions no enhancement in the overall yield was observed. Interestingly, the estimated overall Monod kinetic parameters showed higher rates at mesophilic than thermophilic conditions.

  6. First principles study of (Cd, Hg, In, Tl, Sn, Pb, As, Sb, Bi, Se) modified Pt(111), Pt(100) and Pt(211) electrodes as CO oxidation catalysts

    DEFF Research Database (Denmark)

    Tripkovic, Vladimir

    2015-01-01

    CO oxidation is a prototype reaction for studying oxidation of small organic molecules. Certain adatom modified Pt electrodes have a large promotional effect on CO oxidation. However, the effect is often coverage dependent, and has a limited effect due to short lifetimes of the adatoms. The cover...

  7. Brain Plasticity and Aerobic Fitness

    OpenAIRE

    Thomas, Adam G.; Johansen-Berg, Heidi; Bandettini, Peter

    2014-01-01

    Regular aerobic exercise has a wide range of positive effects on health and cognition. Exercise has been demonstrated to provide a particularly powerful and replicable method of triggering a wide range of structural changes within both human and animal brains. However, the details and mechanisms of these changes remain poorly understood. This thesis undertakes a comprehensive examination of the relationship between brain plasticity and aerobic exercise. A large, longitudinal experiment ...

  8. Identification of Subnanometric Ag Species, Their Interaction with Supports and Role in Catalytic CO Oxidation

    Directory of Open Access Journals (Sweden)

    Yulia Kotolevich

    2016-04-01

    Full Text Available The nature and size of the real active species of nanoparticulated metal supported catalysts is still an unresolved question. The technique of choice to measure particle sizes at the nanoscale, HRTEM, has a practical limit of 1 nm. This work is aimed to identify the catalytic role of subnanometer species and methods to detect and characterize them. In this frame, we investigated the sensitivity to redox pretreatments of Ag/Fe/TiO2, Ag/Mg/TiO2 and Ag/Ce/TiO2 catalysts in CO oxidation. The joint application of HRTEM, SR-XRD, DRS, XPS, EXAFS and XANES methods indicated that most of the silver in all samples is in the form of Ag species with size <1 nm. The differences in catalytic properties and sensitivity to pretreatments, observed for the studied Ag catalysts, could not be explained taking into account only the Ag particles whose size distribution is measured by HRTEM, but may be explained by the presence of the subnanometer Ag species, undetectable by HRTEM, and their interaction with supports. This result highlights their role as active species and the need to take them into account to understand integrally the catalysis by supported nanometals.

  9. Step dynamics and oxide formation during CO oxidation over a vicinal Pd surface.

    Science.gov (United States)

    Shipilin, Mikhail; Gustafson, Johan; Zhang, Chu; Merte, Lindsay Richard; Lundgren, Edvin

    2016-07-27

    In an attempt to bridge the material and pressure gaps - two major challenges for an atomic scale understanding of heterogeneous catalysis - we employed high-energy surface X-ray diffraction as a tool to study the Pd(553) surface in situ under changing reaction conditions during CO oxidation. The diffraction patterns recorded under CO rich reaction conditions are characteristic for the metallic state of the surface. In an environment with low excess of O2 over the reaction stoichiometry, the surface seems to accommodate oxygen atoms along the steps forming one or several subsequent adsorbate structures and rapidly transforms into a combination of (332), (111) and (331) facets likely providing the room for the formation of a surface oxide. For the case of large excess of O2, the diffraction data show the presence of a multilayer PdO with the [101] crystallographic direction parallel to the [111] and the [331] directions of the substrate. The reconstructions in O2 excess are to a large extent similar to those previously reported for pure O2 exposures by Westerström et al. [R. Westerström et al., Phys. Rev. B: Condens. Matter Mater. Phys., 2007, 76, 155410]. PMID:26805438

  10. CO oxidation catalyzed by ag nanoparticles supported on SnO/CeO2

    KAUST Repository

    Khan, Inayatali

    2015-01-01

    Ag-Sn/CeO2 catalysts were synthesized by the co-precipitation method with different Ag-Sn wt.% loadings and were tested for the oxidation of CO. The catalysts were characterized by powder X-ray diffractometry (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray spectroscopy (EDS), and selected area electron diffraction (SAED) techniques. UV-Vis measurements were carried out to elucidate the ionic states of the silver particles, and the temperature-programmed reduction (TPR) technique was employed to check the reduction temperature of the catalyst supported on CeO2. There are peaks for silver crystallites in the X-ray diffraction patterns and the presence of SnO was not well evidenced by the XRD technique due to sintering inside the 3D array channels of CeO2 during the calcination process. The Ag-Sn/CeO2 (4%) catalyst was the most efficient and exhibited 100% CO oxidation at 100 °C due to small particle size and strong electronic interaction with the SnO/CeO2 support. © 2015 Sociedade Brasileira de Química.

  11. CO Oxidation over Pd/ZrO2 Catalysts: Role of Support′s Donor Sites

    Directory of Open Access Journals (Sweden)

    Aleksey A. Vedyagin

    2016-09-01

    Full Text Available A series of supported Pd/ZrO2 catalysts with Pd loading from 0.2 to 2 wt % was synthesized. The ZrO2 material prepared by a similar technique was used as a reference sample. The samples have been characterized by means of transmission electron microscopy (TEM, X-ray diffraction analysis (XRD, X-ray photoelectron spectroscopy (XPS, temperature-programmed reduction (TPR, testing reaction of ethane hydrogenolysis (HGE, N2 adsorption, and electron paramagnetic resonance (EPR spectroscopy. 1,3,5-trinitrobenzene was used as a probe molecule for the EPR spin probe method. The catalytic performance of samples was tested in the model reaction of CO oxidation. It was shown that the concentration of donor sites of support measured by EPR spin probe correlates with catalytic behavior during light-off tests. Low concentration of donor sites on a support’s surface was found to be caused by the presence of the specific surface defects that are related to existence of coordinately unsaturated structures.

  12. CO oxidation on Ta-Modified SnO2 solid solution catalysts

    Science.gov (United States)

    Han, Xue; Xu, Xianglan; Liu, Wenming; Wang, Xiang; Zhang, Rongbin

    2013-06-01

    Co-precipitation method was adopted to prepare Sn-Ta mixed oxide catalysts with different Sn/Ta molar ratios and used for CO oxidation. The catalysts were investigated by N2-Brunauer-Emmett-Teller (N2-BET), X-ray diffraction patterns (XRD), H2-temperature programmed reduction (H2-TPR), Thermal Gravity Analysis - Differential Scanning Calorimetry (TGA-DSC) techniques. It is revealed that a small amount of Ta cations can be doped into SnO2 lattice to form solid solution by co-precipitation method, which resulted in samples having higher surface areas, improved thermal stability and more deficient oxygen species on the surface of SnO2. As a result, those Sn rich Sn-Ta solid solution catalysts with an Sn/Ta molar ratio higher than 4/2 showed significantly enhanced activity as well as good resistance to water deactivation. It is noted here that if tantala disperses onto SnO2 surface instead of doping into its lattice, it will then have negative effect on its activity.

  13. Activity of carbon supported Pt3Ru2 nanocatalyst in CO oxidation

    Directory of Open Access Journals (Sweden)

    KSENIJA DJ. POPOVIĆ

    2009-08-01

    Full Text Available The electrocatalytic activity of Pt3Ru2/C nanocatalyst toward the electro-oxidation of bulk CO was examined in acid and alkaline solution at ambient temperature using the thin-film, rotating disk electrode (RDE method. The catalyst was characterized by XRD analysis. The XRD pattern revealed that the Pt3Ru2/C catalyst consisted of two structures, i.e., Pt–Ru-fcc and Ru-hcp (a solid solution of Ru in Pt and a small amount of Ru or a solid solution of Pt in Ru. Electrocatalytic activities were measured by applying potentiodynamic and steady state techniques. The oxidation of CO on the Pt3Ru2/C catalyst was influenced by pH and anions from the supporting electrolytes. The Pt3Ru2/C was more active in alkaline than in acid solution, as well as in perchloric than in sulfuric acid. Comparison of CO oxidation on Pt3Ru2/C and Pt/C revealed that the Pt3Ru2/C was more active than Pt/C in acid solution, while both catalysts had a similar activity in alkaline solution.

  14. Enzymatic Screening and Molecular Characterization of Thermophilic Bacterial Strains Isolated from Hotspring of Tatopani, Bhurung, Nepal

    OpenAIRE

    Hriush Adhikari; Sangam Ghimire; Binod Khatri; Yuvraj K.C.

    2015-01-01

    Background and Aim: In Nepal not much of study of Thermophilic area and Thermophiles have been done. Thermophilic bacteria are less studied but are important group of microorganisms due to their ability to produce industrially important enzymes. Methods: In this study, thermophilic bacteria were isolated from hot spring of Bhurung, Nepal. Wide range of bacteria that could grow at high temperatures and tolerate extreme temperature were characterized by morphology, biochemistry and sequencing o...

  15. Microbial influenced corrosion by thermophilic bacteria

    Science.gov (United States)

    Lata, Suman; Sharma, Chhaya; Singh, Ajay

    2012-03-01

    The present study was undertaken to investigate microbial influenced corrosion (MIC) on stainless steels due to thermophilic bacteria Desulfotomaculum nigrificans. The objective of the study was to measure the extent of corrosion and correlate it with the growth of the biofilm by monitoring the composition of its extracellular polymeric substances (EPS). The toxic effect of heavy metals on MIC was also observed. For this purpose, stainless steels 304L, 316L and 2205 were subjected to electrochemical polarization and immersion tests in the modified Baar's media, control and inoculated, in anaerobic conditions at room temperature. Scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS) were used to identify the chemicals present in/outside the pit. The results show maximum corrosive conditions when bacterial activity is highest, which in turn minimizes the amount of carbohydrate and protein along with the increase in the fraction of uronic acid in carbohydrate in EPS of the biofilm. However, although bacterial activity and corrosion rate decreases, the amount of biofilm components continue to increase. It is also observed that the toxicity of metals ions affect the bacterial activity and EPS production. It was observed that Desulfotomaculum sp. has the ability to biodegrade its own EPS.

  16. An Immunological Assay for Detection and Enumeration of Thermophilic Biomining Microorganisms

    OpenAIRE

    Amaro, Ana M.; Hallberg, Kevin B.; Lindström, E. Börje; Jerez, Carlos A.

    1994-01-01

    A specific, fast, and sensitive nonradioactive immunobinding assay for the detection and enumeration of the moderate thermophile Thiobacillus caldus and the thermophilic archaeon Sulfolobus acidocaldarius was developed. It employs enhanced chemiluminescence or peroxidase-conjugated immunoglobulins in a dot or slot blotting system and is very convenient for monitoring thermophilic bioleaching microorganisms in effluents from industrial bioleaching processes.

  17. Improving water tolerance of Co3O4 by SnO2 addition for CO oxidation

    Science.gov (United States)

    Xu, Xianglan; Sun, Xiongfei; Han, Hong; Peng, Honggen; Liu, Wenming; Peng, Xing; Wang, Xiang; Yang, Xiangjie

    2015-11-01

    A series of Sn-modified Co3O4 catalysts with different Co/Sn molar ratios were prepared via co-precipitation method and characterized by N2-BET, XRD, H2-TPR, XPS and FTIR techniques. The addition of a small amount of Sn into Co3O4 has a mild influence on its CO oxidation activity, but promotes its water resistance evidently. The major reason is attributed to the effective suppressing of water adsorption on the catalyst surface by Sn addition, as testified by FTIR results. Co0.90Sn0.10, a catalyst with a Co/Sn molar ratio of 0.90/0.10, shows the potential to be used in some real emission control processes for CO oxidation due to its reasonable activity and evidently improved reaction stability in the presence of water vapour.

  18. Role of ammonia-oxidizing bacteria in micropollutant removal from wastewater with aerobic granular sludge.

    Science.gov (United States)

    Margot, Jonas; Lochmatter, Samuel; Barry, D A; Holliger, Christof

    2016-01-01

    Nitrifying wastewater treatment plants (WWTPs) are more efficient than non-nitrifying WWTPs to remove several micropollutants such as pharmaceuticals and pesticides. This may be related to the activity of nitrifying organisms, such as ammonia-oxidizing bacteria (AOBs), which could possibly co-metabolically oxidize micropollutants with their ammonia monooxygenase (AMO). The role of AOBs in micropollutant removal was investigated with aerobic granular sludge (AGS), a promising technology for municipal WWTPs. Two identical laboratory-scale AGS sequencing batch reactors (AGS-SBRs) were operated with or without nitrification (inhibition of AMOs) to assess their potential for micropollutant removal. Of the 36 micropollutants studied at 1 μg l(-1) in synthetic wastewater, nine were over 80% removed, but 17 were eliminated by less than 20%. Five substances (bisphenol A, naproxen, irgarol, terbutryn and iohexol) were removed better in the reactor with nitrification, probably due to co-oxidation catalysed by AMOs. However, for the removal of all other micropollutants, AOBs did not seem to play a significant role. Many compounds were better removed in aerobic condition, suggesting that aerobic heterotrophic organisms were involved in the degradation. As the AGS-SBRs did not favour the growth of such organisms, their potential for micropollutant removal appeared to be lower than that of conventional nitrifying WWTPs. PMID:26877039

  19. CO oxidation at nickel centres by N2O or O2 to yield a novel hexanuclear carbonate.

    Science.gov (United States)

    Horn, Bettina; Limberg, Christian; Herwig, Christian; Feist, Michael; Mebs, Stefan

    2012-08-25

    Reaction of a nickel(0) carbonyl complex, K(2)[L(tBu)NiCO](2), with N(2)O generates a cyclic carbonate compound composed of six [Ni(II)(CO(3))K](+) units. The same product can also be obtained using O(2) as the oxidant in a solid-state/gas reaction. These conversions represent unique examples of a nickel-bound CO oxidation by N(2)O and O(2), respectively. PMID:22785444

  20. Importance of trivalency and the eg1 configuration in the photocatalytic oxidation of water by Mn and Co oxides

    Science.gov (United States)

    Maitra, Urmimala; Naidu, B. S.; Govindaraj, A.; Rao, C. N. R.

    2013-01-01

    Prompted by the early results on the catalytic activity of LiMn2O4 and related oxides in the photochemical oxidation of water, our detailed study of several manganese oxides has shown that trivalency of Mn is an important factor in determining the catalytic activity. Thus, Mn2O3, LaMnO3, and MgMn2O4 are found to be very good catalysts with turnover frequencies of 5 × 10−4 s−1, 4.8 × 10−4 s−1, and 0.8 ×10−4 s−1, respectively. Among the cobalt oxides, Li2Co2O4 and LaCoO3—especially the latter—exhibit excellent catalytic activity, with the turnover frequencies being 9 × 10−4 s−1 and 1.4 × 10−3 s−1, respectively. The common feature among the catalytic Mn and Co oxides is not only that Mn and Co are in the trivalent state, but Co3+ in the Co oxides is in the intermediate t2g5eg1 state whereas Mn3+ is in the t2g3eg1 state. The presence of the eg1 electron in these Mn and Co oxides is considered to play a crucial role in the photocatalytic properties of the oxides. PMID:23818589

  1. Theoretical study on the Si-doped graphene as an efficient metal-free catalyst for CO oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Yanan, E-mail: yntang2010@hotmail.com [Department of Physics and Electronic Science, Zhengzhou Normal University, Zhengzhou, Henan 450044 (China); Quantum Materials Research Center, Zhengzhou Normal University, Henan 450044 (China); Liu, Zhiyong [College of Physics and Electronic Engineering, Henan Normal University, Xinxiang, Henan 453007 (China); Dai, Xianqi [Department of Physics and Electronic Science, Zhengzhou Normal University, Zhengzhou, Henan 450044 (China); Quantum Materials Research Center, Zhengzhou Normal University, Henan 450044 (China); College of Physics and Electronic Engineering, Henan Normal University, Xinxiang, Henan 453007 (China); Yang, Zongxian [College of Physics and Electronic Engineering, Henan Normal University, Xinxiang, Henan 453007 (China); Chen, Weiguang [Department of Physics and Electronic Science, Zhengzhou Normal University, Zhengzhou, Henan 450044 (China); Quantum Materials Research Center, Zhengzhou Normal University, Henan 450044 (China); Ma, Dongwei [College of Physics and Electrical Engineering, Anyang Normal University, Anyang, Henan 455000 (China); Lu, Zhansheng [College of Physics and Electronic Engineering, Henan Normal University, Xinxiang, Henan 453007 (China)

    2014-07-01

    The reduction of noble metal used in carbon monoxide (CO) oxidation remains a challenge. Based on the first-principle methods, the geometry, electronic structure and catalytic properties of Si-doped graphene (Si-graphene) are investigated. The Si adatom has smaller adsorption energy on pristine graphene as compared with that of the Si dopant in graphene. The large atomic radii of Si dopant in graphene can induce the local surface curvature and modulate the electronic structure through inducing the charge redistribution. Besides, the metal-free Si-graphene can weaken the CO adsorption and facilitates the O{sub 2} adsorption, thus enhancing the catalytic activity for CO oxidation. It is found that the preadsorbed O{sub 2} molecule on the Si-atom can greatly enhance the interaction with CO molecule. Moreover, the complete CO oxidation reactions on the Si-graphene include a two-step process of the Eley–Rideal (ER) reactions, in which the first step has a low energy barrier of 0.43 eV and the second step exhibits an even negligible energy barrier of 0.07 eV. The results validate the reactivity of catalysts on the atomic-scale and initiate a clue for fabricating metal-free catalysts with low cost and high activity.

  2. Theoretical study on the Si-doped graphene as an efficient metal-free catalyst for CO oxidation

    Science.gov (United States)

    Tang, Yanan; Liu, Zhiyong; Dai, Xianqi; Yang, Zongxian; Chen, Weiguang; Ma, Dongwei; Lu, Zhansheng

    2014-07-01

    The reduction of noble metal used in carbon monoxide (CO) oxidation remains a challenge. Based on the first-principle methods, the geometry, electronic structure and catalytic properties of Si-doped graphene (Si-graphene) are investigated. The Si adatom has smaller adsorption energy on pristine graphene as compared with that of the Si dopant in graphene. The large atomic radii of Si dopant in graphene can induce the local surface curvature and modulate the electronic structure through inducing the charge redistribution. Besides, the metal-free Si-graphene can weaken the CO adsorption and facilitates the O2 adsorption, thus enhancing the catalytic activity for CO oxidation. It is found that the preadsorbed O2 molecule on the Si-atom can greatly enhance the interaction with CO molecule. Moreover, the complete CO oxidation reactions on the Si-graphene include a two-step process of the Eley-Rideal (ER) reactions, in which the first step has a low energy barrier of 0.43 eV and the second step exhibits an even negligible energy barrier of 0.07 eV. The results validate the reactivity of catalysts on the atomic-scale and initiate a clue for fabricating metal-free catalysts with low cost and high activity.

  3. CTAB assisted hydrothermal synthesis, controlled conversion and CO oxidation properties of CeO2 nanoplates, nanotubes, and nanorods

    International Nuclear Information System (INIS)

    In this work, CeO2 nanoplates were synthesized by a hydrothermal reaction assisted by hexadecyltrimethylammonium bromide (CTAB) at 100-160 deg. C. The size of nanoplates was around 40 nm. Further experiment showed that the controlled conversion of nanoplates into nanotubes, and nanorods can be realized by changing the reaction time, temperature, and CTAB/Ce3+ ratio value. X-ray diffraction (XRD), transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) nitrogen adsorption-desorption measurements were employed to characterize the samples. The CO oxidation properties of nanorods, nanoplates, and nanotubes were investigated. An enhanced catalytic activity has been found for CO oxidation by using CeO2 nanoplates as compared with CeO2 nanotubes and nanorods, and the crystal surfaces (100) of CeO2 nanoplates were considered to play an important role in determining their catalytic oxidation properties. - Graphical abstract: CeO2 nanoplates were synthesized by hydrothermal reactions assisted by CTAB, and the controlled conversion of nanoplates into nanotubes, and nanorods were realized by changing the CTAB/Ce3+ ratio value, reaction time, and temperature. An excellent catalytic activity is found for CO oxidation using CeO2 nanoplates due to their exposed surface (100)

  4. Copper atoms embedded in hexagonal boron nitride as potential catalysts for CO oxidation: A first-principles investigation

    KAUST Repository

    Liu, Xin

    2014-01-01

    We addressed the electronic structure of Cu atoms embedded in hexagonal boron nitride (h-BN) and their catalytic role in CO oxidation by first-principles-based calculations. We showed that Cu atoms prefer to bind directly with the localized defects on h-BN, which act as strong trapping sites for Cu atoms and inhibit their clustering. The strong binding of Cu atoms at boron vacancy also up-shifts the energy level of Cu-d states to the Fermi level and promotes the formation of peroxide-like intermediate. CO oxidation over Cu atoms embedded in h-BN would proceed through the Langmuir-Hinshelwood mechanism with the formation of a peroxide-like complex by reaction of coadsorbed CO and O2, with the dissociation of which the a CO2 molecule and an adsorbed O atom are formed. Then, the embedded Cu atom is regenerated by the reaction of another gaseous CO with the remnant O atom. The calculated energy barriers for the formation and dissociation of peroxide complex and regeneration of embedded Cu atoms are as low as 0.26, 0.11 and 0.03 eV, respectively, indicating the potential high catalytic performance of Cu atoms embedded in h-BN for low temperature CO oxidation. © the Partner Organisations 2014.

  5. Monodisperse Pt atoms anchored on N-doped graphene as efficient catalysts for CO oxidation: A first-principles investigation

    KAUST Repository

    Liu, Xin

    2015-01-01

    We performed first-principles based calculations to investigate the electronic structure and the potential catalytic performance of Pt atoms monodispersed on N-doped graphene in CO oxidation. We showed that N-doping can introduce localized defect states in the vicinity of the Fermi level of graphene which will effectively stabilize the deposited Pt atoms. The binding energy of a single Pt atom onto a stable cluster of 3 pyridinic N (PtN3) is up to -4.47 eV, making the diffusion and aggregation of anchored Pt atoms difficult. Both the reaction thermodynamics and kinetics suggest that CO oxidation over PtN3 would proceed through the Langmuir-Hinshelwood mechanism. The reaction barriers for the formation and dissociation of the peroxide-like intermediate are determined to be as low as 0.01 and 0.08 eV, respectively, while that for the regeneration is only 0.15 eV, proving the potential high catalytic performance of PtN3 in CO oxidation, especially at low temperatures. The Pt-d states that are up-shifted by the Pt-N interaction account for the enhanced activation of O2 and the efficient formation and dissociation of the peroxide-like intermediate.

  6. Non-Gaussian noise-enhanced stochastic rate oscillations in CO oxidation on nanometer-sized Pd particles

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The effect of non-Gaussian colored noise(NGN),mainly its departure q from the Gaussian noise,on the optimal ISRO of CO oxidation on nanometer-sized Pd particles was studied.It was found that the ISRO in the absence of external noise can still be enhanced when the NGN is applied.Specifically,the ISRO varies with changing q and becomes more regular at an appropriate q value,and when q is optimal,the ISRO becomes the most regular.Because the departure q from the Gaussian noise determines the probability distribution function and hence may denote the types of noise,this result shows that different types of external noise can enhance the ISRO of CO oxidation,and non-Gaussian noise may enhance the ISRO more greatly than the Gaussian noise.Therefore,non-Gaussian noise could play more effective roles in the catalytic process of CO oxidation on nanometer-sized Pd particles.

  7. Low-cost step aerobics system with virtual aerobics trainer

    OpenAIRE

    Rosa, Alejandro; Barbancho, Isabel; Tardón, Lorenzo J.; Barbancho, Ana M.

    2014-01-01

    In this paper a low-cost step-aerobics instructor simulation system is presented. The proposed system analyses a given song to iden- tify its rhythmic pattern. Subsequently, this rhythmic pattern is used in order to issue a set of steps-aerobics commands to the user, thus simu- lating a training session. The system uses a Wii Balance Board to track exercises performed by users and runs on an Android smartphone. A set of tests were conducted to assess user experience and opin...

  8. THERMOPHILE ENDOSPORES HAVE RESPONSIVE EXOSPORIUM FOR ATTACHMENT

    Energy Technology Data Exchange (ETDEWEB)

    PANESSA-WARREN,B.; TORTORA,G.T.; WARREN,J.; SABATINI,R.

    1999-08-01

    Recently studies examining the colonization of Clostridial pathogens on agar and human tissue culture cells, demonstrated that (C. sporogenes ATCC 3584, C. difficile ATCC 43594 [patient isolate], C. difficile ATCC 9689 [non-clinical], C. clostridioforme [patient isolate]) bacterial spores (endospores) of the genus Clostridia have an outer membrane that becomes responsive at activation and exhibits extensions of the exosporial membrane that facilitate and maintain spore attachment to a nutritive substrate during germination and initial outgrowth of the newly developed bacterial cell. Therefore this attachment phenomenon plays an important role in insuring bacterial colonization of a surface and the initial stages of the infective process. To see if other non-clinical members of this genus also have this ability to attach to a substrate or food-source during spore germination, and how this attachment process in environmental thermophiles compares to the clinical paradigm (in relation to time sequence, exosporial membrane structure, type of attachment structures, composition of the membrane etc...), sediment samples were collected in sterile transport containers at 4 geothermal sites at Yellowstone National Park in Wyoming. Because spore forming bacteria will produce spores when conditions are unfavorable for growth, the samples were sealed and stored at 4 C. After 8 months the samples were screened for the presence of spores by light microscope examination using malachite green/safranin, and traditional endospores were identified in significant quantities from the Terrace Spring site (a 46 C lake with bacterial mats and a rapidly moving run-off channel leading to a traditional hot spring). The highest spore population was found in the top sediment and benthic water of the run-off channel, pH 8.1.

  9. Monitoring transitory profiles of leachate humic substances in landfill aeration reactors in mesophilic and thermophilic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Tong, Huanhuan [Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, 637141 (Singapore); School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Yin, Ke; Ge, Liya; Giannis, Apostolos [Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, 637141 (Singapore); Chuan, Valerie W.L. [School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore); Wang, Jing-Yuan, E-mail: JYWANG@ntu.edu.sg [Residues and Resource Reclamation Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, CleanTech One, 637141 (Singapore); School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore)

    2015-04-28

    Highlights: • Polymerization and condensation of humic substances (HS) were enhanced by aeration. • Carboxylic group was enriched in HS by aeration presenting improved hydrophilicity. • Mobility of humic acid, as a result was enhanced by aeration especially in young landfill. • Waste age plays an important role in leachate management during aeration. - Abstract: The presence of humic substances (HS) in landfill leachate is of great interest because of their structural stability and potential toxicity. This study examined the effects of temperature and waste age on the transformation of HS during in situ aeration of bioreactor landfills. By establishing aerobic conditions, dissolved organic carbon (DOC) rapidly accumulated in the bioreactor leachate. Fractional analysis showed that the elevated concentration of humic acids (HAs) was primarily responsible for the increment of leachate strength. Further structural characterization indicated that the molecular weight (MW) and aromacity of HS were enhanced by aeration in conjunction with thermophilic temperature. Interestingly, elevation of HAs concentration was not observed in the aeration reactor with a prolonged waste age, as the mobility of HAs was lowered by the high MW derived from extended waste age. Based on these results, aeration may be more favorable in aged landfills, since dissolution of HAs could be minimized by the evolution to larger MW compared to young landfills. Moreover, increased operation temperature during aeration likely offers benefits for the rapid maturation of HS.

  10. Melghiribacillus thermohalophilus gen. nov., sp. nov., a novel filamentous, endospore-forming, thermophilic and halophilic bacterium.

    Science.gov (United States)

    Addou, Nariman Ammara; Schumann, Peter; Spröer, Cathrin; Ben Hania, Wajdi; Hacene, Hocine; Fauque, Guy; Cayol, Jean-Luc; Fardeau, Marie-Laure

    2015-04-01

    A novel filamentous, endospore-forming, thermophilic and moderately halophilic bacterium designated strain Nari2A(T) was isolated from soil collected from an Algerian salt lake, Chott Melghir. The novel isolate was Gram-staining-positive, aerobic, catalase-negative and oxidase-positive. Optimum growth occurred at 50-55 °C, 7-10% (w/v) NaCl and pH 7-8. The strain exhibited 95.4, 95.4 and 95.2% 16S rRNA gene sequence similarity to Thalassobacillus devorans G19.1(T), Sediminibacillus halophilus EN8d(T) and Virgibacillus kekensis YIM-kkny16(T), respectively. The major menaquinone was MK-7. The polar lipid profile consisted of phosphatidylglycerol, diphosphatidylglycerol, three unknown phosphoglycolipids and two unknown phospholipids. The predominant cellular fatty acids were iso-C(15 : 0) and iso-C(17 : 0). The DNA G+C content was 41.9 mol%. Based on the phenotypic, chemotaxonomic and phylogenetic data, strain Nari2A(T) is considered to represent a novel species of a new genus in the family Bacillaceae , order Bacillales , for which the name Melghiribacillus thermohalophilus gen. nov., sp. nov. is proposed. The type strain of Melghiribacillus thermohalophilus is Nari2A(T) ( = DSM 25894(T) = CCUG 62543(T)). PMID:25604343

  11. [Biodegradation of organic pollutants by thermophiles and their applications: a review].

    Science.gov (United States)

    Cui, Jing-Lan; Chen, Chen; Qin, Zhi-Hui; Yu, Chun-Na; Shen, Hui; Shen, Chao-Feng; Chen, Ying-Xu

    2012-11-01

    Persistent organic pollutants have increasingly become a critical environmental concern, while thermophiles have the high potential of degrading various kinds of environmental organic pollutants. At high temperatures, thermophiles have higher metabolic activity, and the competition by mesophiles is reduced, meanwhile, the solubility and bioavailability of some persistent organic pollutants are greatly increased, and thus, the degradation of the pollutants by thermophiles is more rapid and complete. Therefore, thermophils are of great significance for the bio-treatment of organic wastewater and the bioremediation of organic pollutants-contaminated sites. This paper introduced the research progress on the degradation of organic pollutants by thermophiles in terms of the characteristics of thermophiles in degrading organic pollutants, the effects of temperature on the degradation, the degradation pathways, the degradation enzymes, their coding genes, and practical engineering applications. The future research directions including the degradation mechanisms of thermophiles, their resources reserve, related technology strategies and their applications were also prospected. PMID:23431811

  12. Aerobic exercise in pulmonary rehabilitation

    Directory of Open Access Journals (Sweden)

    Thiago Brasileiro de Vasconcelos

    2013-01-01

    Full Text Available The aim of this study was to conduct a literature review on the usefulness of aerobic exercise in pulmonary rehabilitation. This is an exploratory study of literature through the electronic databases Medline, Lilacs, Scielo, Pubmed and Google Scholar, published between 1996 and 2012, conducted during the period February to May 2012 with the following keywords: COPD, pulmonary rehabilitation, aerobic exercises, physical training, quality of life. The change in pulmonary function and dysfunction of skeletal muscles that result in exercise intolerance and reduced fitness and may cause social isolation, depression, anxiety and addiction. The training exercise is the most important component of the program of pulmonary rehabilitation where the aerobic training provides consistent results in clinical improvement in levels of exercise tolerance and decreased dyspnea generating more benefits to the body, reducing the chance of cardiovascular disease and improves quality and expectation of life. We demonstrated that the use of aerobic exercise in pulmonary rehabilitation program, allows an improvement of motor skills, decreased muscle fatigue and deconditioning, reducing sedentary lifestyle; however, has little or no effect on the reduction of strength and atrophy muscle.

  13. Design of A solar Thermophilic Anaerobic Reactor for Small Farms

    NARCIS (Netherlands)

    Mashad, El H.; Loon, van W.K.P.; Zeeman, G.; Bot, G.P.A.; Lettinga, G.

    2004-01-01

    A 10 m(3) completely stirred tank reactor has been designed for anaerobic treatment of liquid cow manure under thermophilic conditions (50degreesC), using a solar heating system mounted on the reactor roof. Simulation models for two systems have been developed. The first system consists of loose com

  14. Abiotic and microbiotic factors controlling biofilm formation by thermophilic sporeformers

    NARCIS (Netherlands)

    Zhao, Y.; Caspers, M.P.M.; Metselaar, K.I.; Boer, de P.; Roeselers, G.; Moezelaar, R.; Nierop Groot, M.N.; Montijn, R.C.; Abee, T.; Kort, R.

    2013-01-01

    One of the major concerns in the production of dairy concentrates is the risk of contamination by heat-resistant spores from thermophilic bacteria. In order to acquire more insight in the composition of microbial communities occurring in the dairy concentrate industry, a bar-coded 16S amplicon seque

  15. Abiotic and Microbiotic Factors Controlling Biofilm Formation by Thermophilic Sporeformers

    NARCIS (Netherlands)

    Zhao, Y.; Caspers, M.P.M.; Metselaar, K.I.; Boer, P. de; Roeselers, G.; Moezelaar, R.; Groot, M.N.; Montijn, R.C.; Abee, T.; Korta, R.

    2013-01-01

    One of the major concerns in the production of dairy concentrates is the risk of contamination by heat-resistant spores from thermophilic bacteria. In order to acquire more insight in the composition of microbial communities occurring in the dairy concentrate industry, a bar-coded 16S amplicon seque

  16. Diversity and ecophysiological features of thermophilic carboxydotrophic anaerobes

    NARCIS (Netherlands)

    Sokolova, T.G.; Henstra, A.M.; Sipma, J.; Parshina, S.N.; Stams, A.J.M.; Lebedinsky, A.V.

    2009-01-01

    Both natural and anthropogenic hot environments contain appreciable levels of carbon monoxide (CO). Anaerobic microbial communities play an important role in CO conversion in such environments. CO is involved in a number of redox reactions. It is biotransformed by thermophilic methanogens, acetogens

  17. Hydrophobic and Electrostatic Cell Surface Properties of Thermophilic Dairy Streptococci

    NARCIS (Netherlands)

    Van der Mei, HC; de Vries, Jacob; Busscher, HJ

    1993-01-01

    Microbial adhesion to hydrocarbons (MATH) and microelectrophoresis were done in 10 mM potassium phosphate solutions to characterize the surfaces of thermophilic dairy streptococci, isolated from pasteurizers. Regardless of whether they were grown (in M17 broth) with lactose, sucrose, or glucose adde

  18. Effect of cobalt on the Anaerobic Thermophilic Conversion of Methanol

    NARCIS (Netherlands)

    Paulo, P.L.; Jiang, B.; Cysneiros, D.; Stams, A.J.M.

    2004-01-01

    The importance of cobalt on the anaerobic conversion of methanol under thermophilic conditions was studied in three parallel lab-scale UASB-reactors and in cobalt-limited enriched cultures. Reactors R1, R2, and R3 were fed with methanol in a bicarbonate-buffered medium, supplied with iron and macron

  19. Survival of thermophilic and hyper-thermophilic microorganisms after exposure to UV-C, ionizing radiation and desiccation

    International Nuclear Information System (INIS)

    In this study, we investigated the ability of several (hyper-) thermophilic Archaea and phylo-genetically deep-branching thermophilic Bacteria to survive high fluences of monochromatic UV-C (254 nm) and high doses of ionizing radiation, respectively. Nine out of fourteen tested microorganisms showed a surprisingly high tolerance against ionizing radiation, and two species (Aquifex pyrophilus and Ignicoccus hospitalis) were even able to survive 20 kGy. Therefore, these species had a comparable survivability after exposure to ionizing radiation such as Deinococcus radiodurans. In contrast, there was nearly no difference in survival of the tested strains after exposure to UV-C under anoxic conditions. If the cells had been dried in advance of UV-C irradiation, they were more sensitive to UV-C radiation compared with cells irradiated in liquid suspension; this effect could be reversed by the addition of protective material like sulfidic ores before irradiation. By exposure to UV-C, photoproducts were formed in the DNA of irradiated Archaea and Bacteria. The distribution of the main photoproducts was species specific, but the amount of the photoproducts was only partly dependent on the applied fluence. Overall, our results show that tolerance to radiation seems to be a common phenomenon among thermophilic and hyper-thermophilic microorganisms. (authors)

  20. Thermophilic hydrogen production from sludge pretreated by thermophilic bacteria: analysis of the advantages of microbial community and metabolism.

    Science.gov (United States)

    Zheng, He-Shan; Guo, Wan-Qian; Yang, Shan-Shan; Feng, Xiao-Chi; Du, Juan-Shan; Zhou, Xian-Jiao; Chang, Jo-Shu; Ren, Nan-Qi

    2014-11-01

    In this study, the effects of thermophilic bacteria pretreatment and elevated fermentation temperature on hydrogen production from sludge were examined. The highest hydrogen yield of 19.9mlH2g(-1) VSS was achieved at 55°C by using pretreated sludge, which was 48.6% higher than raw sludge without pretreatment, and 28.39% higher than when fermented at 35°C. To explore the internal factors of this superior hydrogen production performance, the microbial community and the metabolism analysis were performed by using high-throughput sequencing and excitation-emission matrix. The pretreated sludge showed better utilization of dissolved organic matter and less inhibition of metabolism, especially at thermophilic condition. The 454 sequencing data indicated that microbial abundance was distinctly reduced and extremely high proportion of hydrogen-producing bacteria was found in the thermophilic community (Thermoanaerobacterium accounted for 93.75%). Thus, the pretreated sludge and thermophilic condition showed significant advantages in the hydrogen production using waste sludge as substrate.

  1. Understanding Trends in Catalytic Activity: The Effect of Adsorbate-Adsorbate Interactions for CO Oxidation Over Transition Metals

    DEFF Research Database (Denmark)

    Grabow, Lars; Larsen, Britt Hvolbæk; Nørskov, Jens Kehlet

    2010-01-01

    Using high temperature CO oxidation as the example, trends in the reactivity of transition metals are discussed on the basis of density functional theory (DFT) calculations. Volcano type relations between the catalytic rate and adsorption energies of important intermediates are introduced...... and the effect of adsorbate-adsorbate interaction on the trends is discussed. We find that adsorbate-adsorbate interactions significantly increase the activity of strong binding metals (left side of the volcano) but the interactions do not change the relative activity of different metals and have a very small...... influence on the position of the top of the volcano, that is, on which metal is the best catalyst....

  2. Analysis of Metabolic Pathways and Fluxes in a Newly Discovered Thermophilic and Ethanol-Tolerant Geobacillus Strain

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Yinjie J.; Sapra, Rajat; Joyner, Dominique; Hazen, Terry C.; Myers, Samuel; Reichmuth, David; Blanch, Harvey; Keasling, Jay D.

    2009-01-20

    A recently discovered thermophilic bacterium, Geobacillus thermoglucosidasius M10EXG, ferments a range of C5 (e.g., xylose) and C6 sugars (e.g., glucose) and istolerant to high ethanol concentrations (10percent, v/v). We have investigated the central metabolism of this bacterium using both in vitro enzyme assays and 13C-based flux analysis to provide insights into the physiological properties of this extremophile and explore its metabolism for bio-ethanol or other bioprocess applications. Our findings show that glucose metabolism in G. thermoglucosidasius M10EXG proceeds via glycolysis, the pentose phosphate pathway, and the TCA cycle; the Entner?Doudoroff pathway and transhydrogenase activity were not detected. Anaplerotic reactions (including the glyoxylate shunt, pyruvate carboxylase, and phosphoenolpyruvate carboxykinase) were active, but fluxes through those pathways could not be accuratelydetermined using amino acid labeling. When growth conditions were switched from aerobic to micro-aerobic conditions, fluxes (based on a normalized glucose uptake rate of 100 units (g DCW)-1 h-1) through the TCA cycle and oxidative pentose phosphate pathway were reduced from 64+-3 to 25+-2 and from 30+-2 to 19+-2, respectively. The carbon flux under micro-aerobic growth was directed formate. Under fully anerobic conditions, G. thermoglucosidasius M10EXG used a mixed acid fermentation process and exhibited a maximum ethanol yield of 0.38+-0.07 mol mol-1 glucose. In silico flux balance modeling demonstrates that lactate and acetate production from G. thermoglucosidasius M10EXG reduces the maximum ethanol yieldby approximately threefold, thus indicating that both pathways should be modified to maximize ethanol production.

  3. Digestion with initial thermophilic hydrolysis step for sanitation and enhanced methane extraction in wastewater treatment plants; Roetning med inledande termofilt hydrolyssteg foer hygienisering och utoekad metanutvinning paa avloppsreningsverk

    Energy Technology Data Exchange (ETDEWEB)

    Persson, Emelie; Ossiansson, Elin [BioMil AB, Lund (Sweden); Carlsson, My; Uldal, Martina; Johannesson, Sofia [AnoxKaldnes AB, Lund (Sweden)

    2012-02-15

    other sludge samples. The VS reduction increased more than the methane production as a result of thermophilic pre-hydrolysis prior to mesophilic AD. Possible explanations are loss of hydrogen gas and/or volatile organic compounds in the pre-hydrolysis step, partially aerobic degradation and errors in the gas flow measurements. None of the performed measurements or analyses can confirm the cause, but loss of methane potential through hydrogen release in the pre-hydrolysis step seems most likely. The study has shown that thermophilic pre-hydrolysis has a hygienising effect. In the pilot trial with pre-hydrolysis at 6 hours exposure time and 1.5 days hydraulic retention time the requirements for pathogen reduction that have been suggested for sewage sludge for Salmonella and E-coli were reached, but could not be reached with respect to Enterococcus. In the lab-scale trials with 24 h exposure time the same level of pathogen reduction could not be reached. The results were in these cases inconsequent and difficult to interpret, both from pasteurization and from thermophilic pre-hydrolysis. A possible explanation for this could be that the area of contact per volume is considerably larger in lab scale than in pilot scale. The gas produced in the pre-hydrolysis step needs to be introduced into the main digester in order for it to be fully utilized. If there is a risk that the concentration of hydrogen gas in the pre-hydrolysis step can exceed 25 % by volume, the safety requirements of the plant need to be revised. Simulations have shown that the hydrogen level may momentarily increase after intermittent feeding, so this should be further investigated.

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

    NARCIS (Netherlands)

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

    2004-01-01

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

  5. Performance and microbial community analysis of two-stage process with extreme thermophilic hydrogen and thermophilic methane production from hydrolysate in UASB reactors

    DEFF Research Database (Denmark)

    Kongjan, Prawit; O-Thong, Sompong; Angelidaki, Irini

    2011-01-01

    The two-stage process for extreme thermophilic hydrogen and thermophilic methane production from wheat straw hydrolysate was investigated in up-flow anaerobic sludge bed (UASB) reactors. Specific hydrogen and methane yields of 89ml-H2/g-VS (190ml-H2/g-sugars) and 307ml-CH4/g-VS, respectively were...

  6. Pathogen inactivation in liquid dairy manure during anaerobic and aerobic digestions

    Science.gov (United States)

    Biswas, S.; Pandey, P.; Castillo, A. R.; Vaddella, V. K.

    2014-12-01

    Controlling manure-borne pathogens such as E. coli O157:H7, Salmonella spp. and Listeria monocytogenes are crucial for protecting surface and ground water as well as mitigating risks to human health. In California dairy farms, flushing of dairy manure (mainly animal feces and urine) from freestall barns and subsequent liquid-solid manure separation is a common practice for handling animal waste. The liquid manure fraction is generally pumped into the settling ponds and it goes into aerobic and/or anaerobic lagoons for extended period of time. Considering the importance of controlling pathogens in animal waste, the objective of the study was to understand the effects of anaerobic and aerobic digestions on the survival of three human pathogens in animal waste. The pathogen inactivation was assessed at four temperatures (30, 35, 42, and 50 °C), and the relationships between temperature and pathogen decay were estimated. Results showed a steady decrease of E. coli levels in aerobic and anaerobic digestion processes over the time; however, the decay rates varied with pathogens. The effect of temperature on Salmonella spp. and Listeria monocytogenes survival was different than the E. coli survival. In thermophilic temperatures (42 and 50 °C), decay rate was considerable greater compared to the mesophilic temperatures (30 and 35°C). The E. coli log reductions at 50 °C were 2.1 in both aerobic and anaerobic digestions after 13 days of incubation. The Salmonella spp. log reductions at 50 °C were 5.5 in aerobic digestion, and 5.9 in anaerobic digestion. The Listeria monocytogenes log reductions at 50 °C were 5.0 in aerobic digestion, and 5.6 in anaerobic digestion. The log reduction of E. coli, Salmonella spp., and Listeria monocytogens at 30 °C in aerobic environment were 0.1, 4.7, and 5.6, respectively. In anaerobic environment, the corresponding reductions were 0.4, 4.3, and 5.6, respectively. We anticipate that the outcomes of the study will help improving the

  7. Aerobic microbial enhanced oil recovery

    Energy Technology Data Exchange (ETDEWEB)

    Torsvik, T. [Univ. of Bergen (Norway); Gilje, E.; Sunde, E.

    1995-12-31

    In aerobic MEOR, the ability of oil-degrading bacteria to mobilize oil is used to increase oil recovery. In this process, oxygen and mineral nutrients are injected into the oil reservoir in order to stimulate growth of aerobic oil-degrading bacteria in the reservoir. Experiments carried out in a model sandstone with stock tank oil and bacteria isolated from offshore wells showed that residual oil saturation was lowered from 27% to 3%. The process was time dependent, not pore volume dependent. During MEOR flooding, the relative permeability of water was lowered. Oxygen and active bacteria were needed for the process to take place. Maximum efficiency was reached at low oxygen concentrations, approximately 1 mg O{sub 2}/liter.

  8. Influence of Ce/Zr ratio on CO oxidation activity of ceria-zirconia supported Cu catalyst

    Science.gov (United States)

    Hattori, Masatomo; Haneda, Masaaki; Ozawa, Masakuni

    2016-01-01

    The influence of Ce/Zr ratios in the cerium-rich region on the dispersibility and reduction property of Cu catalysts supported on ceria-zirconia composite oxides was investigated. In the catalysts, the dispersibility of copper oxide species on ceria-zirconia supports was different depending on Ce/Zr ratio. The particle size of copper oxide species on Ce0.7Zr0.3O2 was smaller than that on Ce0.5Zr0.5O2. CO oxidation activity of 1.0 wt % Cu/Ce0.7Zr0.3O2 was higher than that of 1.0 wt % Cu/Ce0.5Zr0.5O2. Temperature programmed reduction by CO (CO-TPR) measurement revealed that the reducibility of Cu/Ce0.7Zr0.3O2 was higher than that of Cu/Ce0.5Zr0.5O2. The temperature of the first peak in CO-TPR profiles for both catalysts was in good agreement with the temperature at which the conversion of CO reached 50% (T50). It is suggested that the copper oxide species — ceria-zirconia interaction influences the activation of oxygen at the interface between copper oxide species and ceria-zirconia, resulting in different catalytic performance for CO oxidation.

  9. Modification of Pd-CeO 2 catalyst by different treatments: Effect on the structure and CO oxidation activity

    Science.gov (United States)

    Wang, Bin; Weng, Duan; Wu, Xiaodong; Ran, Rui

    2011-02-01

    To investigate the interaction between noble metal and CeO2, a Pd-doped CeO2 catalyst was prepared by sol-gel method, and the catalyst was then treated in static air and a H2/O2 alternating flow at 800 °C, respectively. It is found by step-scanning XRD that Pd ions migrate out of the ceria lattice during the redox treatment, while the exudation of Pd is not so obvious after the oxidative treatment. For the CO oxidation activity, the redox treated catalyst is seriously weakened compared with the oxidative-treated one. This difference is ascribed to the encapsulation of Pd crystallites by the CeO2 support during the redox treatment, which is confirmed by XPS and CO-TPR. Based on the activity and FTIR results, it is proposed that, CO oxidation at low temperatures proceeds mainly via the reaction between the adsorbed CO on Pd sites and the lattice oxygen of surface CeO2 at the Pd-Ce interface.

  10. A kinetic study of CO oxidation over the perovskite-like oxide LaSrNiO4

    Directory of Open Access Journals (Sweden)

    KEJUN WANG

    2010-02-01

    Full Text Available The effect of reactant/product concentrations, reaction temperature and contact time on CO oxidation was investigated, using the perovskite-like oxide LaSrNiO4 as the catalyst. It was found that the reaction order of CO (reactant, as well as that of CO2 (product, is negative, the reaction orders for CO and CO2 being –0.32 and –0.51, respectively. However, the reaction order for O2 is positive, having a value of 0.62. The negative reaction order of CO and CO2 might be due to their competitive adsorption with O2, preventing the proceeding of oxygen dissociation (the rate-determining step of the reaction. The activation energy (Ea of the reaction was calculated to be 49.3 kJ mol-1; this small activation energy suggests that LaSrNiO4 is a potential candidate for the CO oxidation reaction. The optimum weight hourly space velocity (WHSV of the reaction was found to be 0.6 g s cm-3. The reaction conditions in the present case were (0.5–1 % CO + 0.5–2 % O2 + 0–2 % CO2, with He as the balance gas.

  11. Room-temperature cataluminescence from CO oxidation in a non-thermal plasma-assisted catalysis system.

    Science.gov (United States)

    Han, Feifei; Yang, Yuhan; Han, Jiaying; Ouyang, Jin; Na, Na

    2015-08-15

    Cataluminescence (CTL) is a kind of chemiluminescence during catalytic reaction on surface of catalysts under a heated condition. Due to the low catalytic reactivity of CO, normally low intensity of CTL is obtained during heterogeneously catalytic oxidation of CO under heated conditions (normally higher than 150°C), even catalyzed by precious-metal-based catalysts. Therefore, seeking enhanced CTL of CO at room temperature and using low-cost catalysts becomes significant. Here, CTL generated from CO oxidation was firstly reported at room temperature, which was carried out in a non-thermal plasma-assisted (NTPA) catalysis system. With air acting as discharge gas, carrier gas as well as oxidant, a Mn/SiO2 nanomaterials-based NTPA catalysis system was fabricated for CO catalytic oxidation at room temperature, whose temperature was much lower than previous CTL methods. Relatively high and selective CTL responses were acquired during CO oxidation on surface of Mn/SiO2 nanomaterials, whereas no significant CTL signal was recorded without plasma assistance or on other metals-doped SiO2 catalysts. Without any excitation light source or heating element, a low cost and simple CO sensor was fabricated by using common and easily synthesized catalysts. The present work has greatly simplified the constructions, and enlarged CTL applications.

  12. Atomic layer deposition on Pd nanocrystals for forming Pd-TiO2 interface toward enhanced CO oxidation

    Directory of Open Access Journals (Sweden)

    Yu Bai

    2016-06-01

    Full Text Available Pd typically exhibits relatively low catalytic activity in CO oxidation, as CO is apt to be adsorbed on Pd to poison the surface for O2 activation. In this Letter, we report that this limitation can be overcome by integrating Pd with TiO2. The TiO2 was coated on Pd nanocubes with a controllable thickness using atomic layer deposition (ALD method. Given the different work functions of TiO2 and Pd, the electrons in TiO2 semiconductor will flow toward Pd. With the electron density increased on Pd, the adsorption of CO to Pd will be weakened while the oxygen activation can be facilitated. Meanwhile, the interface-confined sites at Pd-TiO2 may further enhance the oxygen activation. As the species adsorption and activation are strongly correlated with electron density, the performance of Pd-TiO2 in CO oxidation turns out to depend on the TiO2 thickness, which determines the number of transferred electrons, within a certain range (<1.8 nm. This work provides a new strategy for enhancing catalytic performance through tailoring charge densities in hybrid catalysts.

  13. Atomic layer deposition on Pd nanocrystals for forming Pd-TiO2 interface toward enhanced CO oxidation

    Institute of Scientific and Technical Information of China (English)

    Yu Bai; Chunlei Wang; Xingyi Zhou; Junling Lu; Yujie Xiong

    2016-01-01

    Pd typically exhibits relatively low catalytic activity in CO oxidation, as CO is apt to be adsorbed on Pd to poison the surface for O2 activation. In this Letter, we report that this limitation can be overcome by integrating Pd with TiO2. The TiO2 was coated on Pd nanocubes with a controllable thickness using atomic layer deposition (ALD) method. Given the different work functions of TiO2 and Pd, the electrons in TiO2 semiconductor will flow toward Pd. With the electron density increased on Pd, the adsorption of CO to Pd will be weakened while the oxygen activation can be facilitated. Meanwhile, the interface-confined sites at Pd-TiO2 may further enhance the oxygen activation. As the species adsorption and activation are strongly correlated with electron density, the performance of Pd-TiO2 in CO oxidation turns out to de-pend on the TiO2 thickness, which determines the number of transferred electrons, within a certain range ( o 1.8 nm). This work provides a new strategy for enhancing catalytic performance through tai-loring charge densities in hybrid catalysts.

  14. Aerobic conditioning for team sport athletes.

    Science.gov (United States)

    Stone, Nicholas M; Kilding, Andrew E

    2009-01-01

    Team sport athletes require a high level of aerobic fitness in order to generate and maintain power output during repeated high-intensity efforts and to recover. Research to date suggests that these components can be increased by regularly performing aerobic conditioning. Traditional aerobic conditioning, with minimal changes of direction and no skill component, has been demonstrated to effectively increase aerobic function within a 4- to 10-week period in team sport players. More importantly, traditional aerobic conditioning methods have been shown to increase team sport performance substantially. Many team sports require the upkeep of both aerobic fitness and sport-specific skills during a lengthy competitive season. Classic team sport trainings have been shown to evoke marginal increases/decreases in aerobic fitness. In recent years, aerobic conditioning methods have been designed to allow adequate intensities to be achieved to induce improvements in aerobic fitness whilst incorporating movement-specific and skill-specific tasks, e.g. small-sided games and dribbling circuits. Such 'sport-specific' conditioning methods have been demonstrated to promote increases in aerobic fitness, though careful consideration of player skill levels, current fitness, player numbers, field dimensions, game rules and availability of player encouragement is required. Whilst different conditioning methods appear equivalent in their ability to improve fitness, whether sport-specific conditioning is superior to other methods at improving actual game performance statistics requires further research.

  15. Methods to determine aerobic endurance.

    Science.gov (United States)

    Bosquet, Laurent; Léger, Luc; Legros, Patrick

    2002-01-01

    Physiological testing of elite athletes requires the correct identification and assessment of sports-specific underlying factors. It is now recognised that performance in long-distance events is determined by maximal oxygen uptake (V(2 max)), energy cost of exercise and the maximal fractional utilisation of V(2 max) in any realised performance or as a corollary a set percentage of V(2 max) that could be endured as long as possible. This later ability is defined as endurance, and more precisely aerobic endurance, since V(2 max) sets the upper limit of aerobic pathway. It should be distinguished from endurance ability or endurance performance, which are synonymous with performance in long-distance events. The present review examines methods available in the literature to assess aerobic endurance. They are numerous and can be classified into two categories, namely direct and indirect methods. Direct methods bring together all indices that allow either a complete or a partial representation of the power-duration relationship, while indirect methods revolve around the determination of the so-called anaerobic threshold (AT). With regard to direct methods, performance in a series of tests provides a more complete and presumably more valid description of the power-duration relationship than performance in a single test, even if both approaches are well correlated with each other. However, the question remains open to determine which systems model should be employed among the several available in the literature, and how to use them in the prescription of training intensities. As for indirect methods, there is quantitative accumulation of data supporting the utilisation of the AT to assess aerobic endurance and to prescribe training intensities. However, it appears that: there is no unique intensity corresponding to the AT, since criteria available in the literature provide inconsistent results; and the non-invasive determination of the AT using ventilatory and heart rate

  16. Thermophile-specific proteins: the gene product of aq_1292 from Aquifex aeolicus is an NTPase

    OpenAIRE

    Klinger, Claudia; Roßbach, Michael; Howe, Rebecca; Kaufmann, Michael

    2003-01-01

    Background To identify thermophile-specific proteins, we performed phylogenetic patterns searches of 66 completely sequenced microbial genomes. This analysis revealed a cluster of orthologous groups (COG1618) which contains a protein from every thermophile and no sequence from 52 out of 53 mesophilic genomes. Thus, COG1618 proteins belong to the group of thermophile-specific proteins (THEPs) and therefore we here designate COG1618 proteins as THEP1s. Since no THEP1 had been analyzed biochemic...

  17. Proteomic analysis of acetylation in thermophilic Geobacillus kaustophilus.

    Science.gov (United States)

    Lee, Dong-Woo; Kim, Dooil; Lee, Yong-Jik; Kim, Jung-Ae; Choi, Ji Young; Kang, Sunghyun; Pan, Jae-Gu

    2013-08-01

    Recent analysis of prokaryotic N(ε)-lysine-acetylated proteins highlights the posttranslational regulation of a broad spectrum of cellular proteins. However, the exact role of acetylation remains unclear due to a lack of acetylated proteome data in prokaryotes. Here, we present the N(ε)-lysine-acetylated proteome of gram-positive thermophilic Geobacillus kaustophilus. Affinity enrichment using acetyl-lysine-specific antibodies followed by LC-MS/MS analysis revealed 253 acetylated peptides representing 114 proteins. These acetylated proteins include not only common orthologs from mesophilic Bacillus counterparts, but also unique G. kaustophilus proteins, indicating that lysine acetylation is pronounced in thermophilic bacteria. These data complement current knowledge of the bacterial acetylproteome and provide an expanded platform for better understanding of the function of acetylation in cellular metabolism.

  18. Startup and stability of thermophilic anaerobic digestion of OFMSW

    KAUST Repository

    El-Fadel, Mutasem E.

    2013-01-01

    Anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) is promoted as an energy source and more recently as a greenhouse gas (GHG) mitigation measure. In this context, AD systems operating at thermophilic temperatures (55-60°C)-compared to mesophilic temperatures (35-40°C)-have the unique feature of producing hygienic soil conditioners with greater process efficiency, higher energy yield, and more GHG savings. Startup of AD systems is often constrained by the lack of acclimated seeds, leading to process instability and failure. The authors focus on strategies to startup thermophilic digesters treating OFMSW in the absence of acclimated seeds and examines constraints associated with process stability and ways to overcome them. Relevant gaps in the literature and future research needs are delineated. © 2013 Taylor & Francis Group, LLC.

  19. Bioleaching of multiple metals from contaminated sediment by moderate thermophiles.

    Science.gov (United States)

    Gan, Min; Jie, Shiqi; Li, Mingming; Zhu, Jianyu; Liu, Xinxing

    2015-08-15

    A moderately thermophilic consortium was applied in bioleaching multiple metals from contaminated sediment. The consortium got higher acidification and metals soubilization efficiency than that of the pure strains. The synergistic effect of the thermophilic consortium accelerated substrates utilization. The utilization of substrate started with sulfur in the early stage, and then the pH declined, giving rise to making use of the pyrite. Community dynamic showed that A. caldus was the predominant bacteria during the whole bioleaching process while the abundance of S. thermotolerans increased together with pyrite utilization. Solubilization efficiency of Zn, Cu, Mn and Cd reached 98%, 94%, 95%, and 89% respectively, while As, Hg, Pb was only 45%, 34%, 22%. Logistic model was used to simulate the bioleaching process, whose fitting degree was higher than 90%. Correlation analysis revealed that metal leaching was mainly an acid solubilization process. Fraction analysis revealed that metals decreased in mobility and bioavailability. PMID:26140749

  20. Widespread Disulfide Bonding in Proteins from Thermophilic Archaea

    Directory of Open Access Journals (Sweden)

    Julien Jorda

    2011-01-01

    Full Text Available Disulfide bonds are generally not used to stabilize proteins in the cytosolic compartments of bacteria or eukaryotic cells, owing to the chemically reducing nature of those environments. In contrast, certain thermophilic archaea use disulfide bonding as a major mechanism for protein stabilization. Here, we provide a current survey of completely sequenced genomes, applying computational methods to estimate the use of disulfide bonding across the Archaea. Microbes belonging to the Crenarchaeal branch, which are essentially all hyperthermophilic, are universally rich in disulfide bonding while lesser degrees of disulfide bonding are found among the thermophilic Euryarchaea, excluding those that are methanogenic. The results help clarify which parts of the archaeal lineage are likely to yield more examples and additional specific data on protein disulfide bonding, as increasing genomic sequencing efforts are brought to bear.

  1. Use of bacteriophage for the selective isolation of thermophilic actinomycetes from composted eucalyptus bark.

    Science.gov (United States)

    Kurtböke, D I; Murphy, N E; Sivasithamparam, K

    1993-01-01

    A method was developed to reduce the numbers of thermophilic bacteria on isolation plates, which in turn facilitated the detection and isolation of thermophilic actinomycetes. The method involves exposing the test material to bacteriophage suspensions prior to inoculation on isolation plates. This method was applied to composted eucalyptus bark samples, which were then inoculated on R8 and 1/2 TSA + 0.2% casein hydrolysate agar plates. The phage susceptibility of thermophilic bacteria provided a selective means of reducing their numbers on isolation plates and hence increased the numbers of Thermomonospora, Saccharopolyspora rectivirgula, and thermophilic Streptomyces spp. on these media in comparison with the numbers recorded from control plates.

  2. State of the art and future perspectives of thermophilic anaerobic digestion

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær; Mladenovska, Zuzana; Iranpour, R.;

    2002-01-01

    The slate of the art of thermophilic digestion is discussed. Thermophilic digestion is a well established technology in Europe for treatment of mixtures of waste in common large scale biogas plants or for treatment of the organic fraction of municipal solid waste. Due to a large number of failures......-up strategy based on the actual activity of key microbes can be used to ensure proper and fast transfer of mesophilic digesters into thermophilic operation. Extreme thermophilic temperatures of 65degreesC or more may be necessary in the future to meet the demands for full sanitation of the waste material...

  3. Solar Thermophilic Anaerobic Reactor (STAR) for Renewable Energy Production

    OpenAIRE

    Mashad, El, H.

    2003-01-01

    Liquid and solid cattle manures are major waste streams inEgypt. The main objective of this research was maximising the net energy production from these wastes by using a solar energy heating system. High concentration of ammonia can strongly affect the gross methane production via inhibition of methanogenesis and reduced hydrolysis. The latter is only limited addressed so far in literature and therefore taken as a second objective of this study.To be able to design a solar thermophilic anaer...

  4. Thermophilic biological nitrogen removal in industrial wastewater treatment.

    OpenAIRE

    Lopez-Vazquez, CM; Kubare, M.; Saroj, DP; Chikamba, C; Schwarz, J.; Daims, H.; Brdjanovic, D.

    2013-01-01

    Nitrification is an integral part of biological nitrogen removal processes and usually the limiting step in wastewater treatment systems. Since nitrification is often considered not feasible at temperatures higher than 40 °C, warm industrial effluents (with operating temperatures higher than 40 °C) need to be cooled down prior to biological treatment, which increases the energy and operating costs of the plants for cooling purposes. This study describes the occurrence of thermophilic biologic...

  5. Sulfur Reduction by the Extremely Thermophilic Archaebacterium Pyrodictium occultum

    OpenAIRE

    Parameswaran, A. K.; Provan, C. N.; Sturm, F. J.; Kelly, R.M.

    1987-01-01

    The relationship between growth and biological sulfur reduction for the extremely thermophilic archaebacterium Pyrodictium occultum was studied over a temperature range of 98 to 105°C. The addition of yeast extract (0.2 g/liter) to the medium was found to increase hydrogen sulfide production significantly, especially at higher temperatures. Sulfide production in uninoculated controls with and without yeast extract was noticeable but substantially below the levels observed in samples containin...

  6. Pt atoms stabilized on hexagonal boron nitride as efficient single-atom catalysts for CO oxidation: A first-principles investigation

    KAUST Repository

    Liu, Xin

    2015-01-01

    Taking CO oxidation as a probe, we investigated the electronic structure and reactivity of Pt atoms stabilized by vacancy defects on hexagonal boron nitride (h-BN) by first-principles-based calculations. As a joint effect of the high reactivity of both a single Pt atom and a boron vacancy defect (PtBV), the Pt-N interaction is -4.40 eV and is already strong enough to prohibit the diffusion and aggregation of the stabilized Pt atom. Facilitated by the upshifted Pt-d states originated from the Pt-N interaction, the barriers for CO oxidation through the Langmuir-Hinshelwood mechanism for formation and dissociation of peroxide-like intermediate and the regeneration are as low as 0.38, 0.10 and 0.04 eV, respectively, suggesting the superiority of PtBV as a catalyst for low temperature CO oxidation.

  7. Purification and characterization of a type B feruloyl esterase (StFAE-A) from the thermophilic fungus Sporotrichum thermophile

    DEFF Research Database (Denmark)

    Topakas, E.; Stamatis, H.; Biely, P.;

    2004-01-01

    . thermophile (a maximum of 34% total ferulic acid released after 1 h incubation). StFAE-A by itself could release FA, but at a level almost 47-fold lower than that obtained in the presence of xylanase. The potential of StFAE-A for the synthesis of various phenolic acid esters was tested using a ternary water......-organic mixture consisting of n-hexane, 1-butanol and water as a reaction system....

  8. Crenalkalicoccus roseus gen. nov., sp. nov., a thermophilic bacterium isolated from alkaline hot springs.

    Science.gov (United States)

    Ming, Hong; Duan, Yan-Yan; Yin, Yi-Rui; Meng, Xiao-Lin; Li, Shuai; Zhou, En-Min; Huang, Jian-Rong; Nie, Guo-Xing; Li, Wen-Jun

    2016-06-01

    Two closely related thermophilic bacterial strains, designated YIM 78023T and YIM 78058, were isolated from samples collected from two alkaline hot springs in Tengchong county, Yunnan province, south-west China. The novel isolates were Gram-stain-negative, non-motile, aerobic ovoid- to coccoid-shaped and non-spore-forming. Strain YIM 78023T grew at 20-60 ºC and pH 6.0-9.0 with optimal growth observed at 40-50 ºC and pH 8.0, while strain YIM 78058 grew at 25-60 ºC and pH 6.0-10.0 with optimal growth at 45-50 ºC and pH 8.0. Phylogenetic analysis based on 16S rRNA gene sequences affiliated these two isolates within the family Acetobacteraceae with high sequence similarities to members of the genera Roseomonas and Belnapia (all sequence similarities <94.5 %). In addition to the above two genera, these strains also clustered with the genera Craurococcus and Paracraurococcus (having sequence similarities <93.3 %) in the phylogenetic tree, but with a distinct lineage within the family Acetobacteraceae. The major ubiquinone was Q-10 and the major fatty acids observed were C18:1ω7c, summed feature 4 and C16:0. The genomic DNA G+C contents observed for strains YIM 78023T and YIM 78058 were 74.3 and 74.0 mol%, respectively. Morphological, phylogenetic and chemotaxonomic results suggest that strains YIM 78023T and YIM 78058 are representatives of a novel species of a new genus within the family Acetobacteraceae, for which the name Crenalkalicoccus roseus gen. nov., sp. nov. is proposed. The type strain of Crenalkalicoccus roseus is YIM 78023T (=JCM 19657T=KACC 17825T).

  9. Energetic and metabolic consequences of aerobic and an-aerobic ATP-production.

    NARCIS (Netherlands)

    Schreurs, V.V.A.M.; Aarts, M.J.; IJssennagger, N.; Hermans, J.; Hendriks, W.H.

    2007-01-01

    ATP, the currency of cellular energy metabolism, can be produced during aerobic and an-aerobic oxidation of metabolic substrates. The aerobic oxidation yields CO2 + H2O as metabolic end products while ATP is produced by oxidative phosphorylation in the mitochondria. Carbohydrate, protein and fat pro

  10. Hemicellulases from the ethanologenic thermophile Thermoanaerobacter ethanolicus and related anaerobic thermophiles. Final report, September 1992--June 1996

    Energy Technology Data Exchange (ETDEWEB)

    Wiegel, J.

    1998-05-01

    The SHORT TERM GOALS of this application were to characterize hemicellulases from anaerobic thermophiles on the biochemical and molecular level to extend the presently limited knowledge of hemicellulases in anaerobic thermophilic bacteria. This objective includes the following TASKS: (1) Traditional purification and biochemical/biophysical characterization of xylanases from the newly isolated, slightly alkalitolerant strain NDF190, and the slightly acid-tolerant strain YS485, both with high xylanolytic activities, and of the 4-0-methyl glucuronidase and arabinosidase from strain NDF190 and the acetyl (xylan) esterase from T. ethanolicus. This also includes determining the N-terminal sequences and obtaining gene probes. (2) Elucidation of the regulation of hemicellulolytic enzymes in anaerobic thermophiles. (3) To clone into E. coli and identify the multiplicity of the enzymes involved in hemicellulose degradation by T. ethanolicus and other suitable organisms. (4) To purify and characterize the recombinant enzymes with the goal of identifying the best enzymes for cloning into the ethanologenic T. ethanolicus to obtain an optimized hemicellulose utilization by this bacterium (one of our long term goals).

  11. Hemicellulases from the ethanologenic thermophile, Thermoanaerobacter ethanolicus and related anaerobic thermophiles. Final report, September 1992--June 1996

    Energy Technology Data Exchange (ETDEWEB)

    Wiegel, J.

    1998-09-01

    The short term goals of this application were to characterize hemicellulases from anaerobic thermophiles on the biochemical and molecular level to extend the presently limited knowledge of hemicellulases in anaerobic thermophilic bacteria. This objective includes the following tasks: (1) Traditional purification and biochemical/biophysical characterization of xylanases from the newly isolated, slightly alkalitolerant strain NDF190, and the slightly acid-tolerant strain YS485, both with high xylanolytic activities, and of the 4-O-methyl glucuronidase and arabinosidase from strain NDF190 and the acetyl (xylan) esterase from T. ethanolicus. This also includes determining the N-terminal sequences and obtaining gene probes. (2) Elucidation of the regulation of hemicellulolytic enzymes in anaerobic thermophiles. (3) To clone into E. coli and identify the multiplicity of the enzymes involved in hemicellulose degradation by T. ethanolicus and other suitable organisms. (4) To purify and characterize the recombinant enzymes with the goal of identifying the best enzymes for cloning into the ethanologenic T. ethanolicus to obtain an optimized hemicellulose utilization by this bacterium.

  12. Computer simulation of spatial coupling in chemical oscillations of CO oxidation on two Pd(110) single crystals

    Science.gov (United States)

    Park, I. J.; Woo, S. I.

    1993-09-01

    Gas-phase coupling between two Pd(110) single crystals in a UHV CO oxidation reaction in a continuous stirred tank reactor (CSTR) has been simulated by solving gas-phase mass balance equations with kinetic rate equations. This work was motivated by the experimental results which show that the frequency of partial pressure change in carbon monoxide is the same as the frequency of the work function change in the oscillation region and that the coupling between the two crystals occurred entirely via CO partial pressure. The computer simulation described here gives qualitative agreement with the experimental results. The change in the oscillatory region originating from the coupling of chemical oscillators which are slightly different to each other is successfully demonstrated by this model. The coupling of two oscillators having a simple periodic oscillation to produce mixed-mode oscillation was also successfully simulated.

  13. CO oxidation mechanism on the γ-Al2O3 supported single Pt atom: First principle study

    Science.gov (United States)

    Gao, Hongwei

    2016-08-01

    Understanding the role of metal-support interaction for the supported single-atom catalysts is very important in heterogeneous catalysis. Here, Three different CO oxidation mechanisms on Pt/γ-Al2O3 catalyst were probed by periodic density functional theory (DFT) calculations in detail, namely the reactive O*sbnd Osbnd C*dbnd O intermediate mechanism, the reactive CO3 intermediate mechanism and the Pt-Al3+ double sites mechanism. According to the calculated results analysis, we concluded that the dominant reaction pathway at the low temperatures is the reactive O*sbnd Osbnd C*dbnd O intermediate mechanism. Our results are in very good agreement with the experimental evidence for O*sbnd Osbnd C*dbnd O coverage on Pt/γ-Al2O3 at room temperature by an in situ diffuse reflectance infrared detector.

  14. CO oxidation catalyzed by the single Co atom embedded hexagonal boron nitride nanosheet: a DFT-D study.

    Science.gov (United States)

    Lu, Zhansheng; Lv, Peng; Liang, Yanli; Ma, Dongwei; Zhang, Yi; Zhang, Wenjin; Yang, Xinwei; Yang, Zongxian

    2016-08-21

    A single metal atom stabilized on two dimensional materials (such as graphene and h-BN) exhibits extraordinary activity in the oxidation of CO. The oxidation of CO by molecular O2 on a single cobalt atom embedded in a hexagonal boron nitride monolayer (h-BN) is investigated using first-principles calculations with dispersion-correction. It is found that the single Co atom prefers to reside in a boron vacancy and possesses great stability. There are three mechanisms for CO oxidation: the traditional Eley-Rideal (ER) and Langmuir-Hinshelwood (LH) mechanisms and the termolecular Eley-Rideal (TER) mechanism proposed recently. Given the relatively small reaction barriers of the rate-limiting steps for the ER, LH and TER mechanisms (0.59, 0.55 and 0.41 eV, respectively), all three mechanisms are able to occur at low temperature. The current study may provide useful clues to develop low cost single atom catalysts.

  15. Density functional study on mechanism of CO oxidation with activated water on O/Au (111 ) surface

    Institute of Scientific and Technical Information of China (English)

    ZHANG WenHua; LI ZhenYu; LUO Yi; YANG JinLong

    2009-01-01

    With density functional theory, the mechanism of water-enhanced CO oxidation on oxygen pre-covered Au (111) surface is theoretically studied. First, water is activated by the pro-covered oxygen atom and dissociates to OHad. group. Then, OHads reacts with COads to form chemisorbed HOCOads. Finally, with the aid of water, HOCOads dissociates to CO2. The whole process can be described as 1/2H2Oads + H2Oads + 1/2Oads+ COads→H3Oads + CO2,gas. One CO2 is formed with only 1/2 pro-covered oxygen atom. That is why more CO2 is observed when water is present on oxygen pro-covered Au (111) surface. Activation energy of each elementary step is low enough to allow the reaction to proceed at low temperature.

  16. Elementary steps in Fischer-Tropsch synthesis: CO bond scission, CO oxidation and surface carbiding on Co(0001)

    Science.gov (United States)

    Weststrate, C. J.; van Helden, P.; van de Loosdrecht, J.; Niemantsverdriet, J. W.

    2016-06-01

    Dissociation of CO on a Co(0001) surface is explored in the context of Fischer-Tropsch synthesis on cobalt catalysts. Experiments show that CO dissociation can occur on defect sites around 330 K, with an estimated barrier between 90 and 104 kJ mol- 1. Despite the ease of CO dissociation on defect sites, extensive carbon deposition onto the cobalt surface up to 0.33 ML requires a combination of high surface temperature and a relatively high CO pressure. Experimental data on the CO oxidation reaction indicate a high reaction barrier for the CO + O reaction, and it is argued that, due to the rather strong Co-O bond, (i) oxygen removal is the rate-limiting step during surface carbidization and (ii) in the context of Fischer-Tropsch synthesis, removal of surface oxygen rather than CO bond scission might be limiting the overall reaction rate.

  17. Biosynthesis of fructo-oligosaccharides by Sporotrichum thermophile during submerged batch cultivation in high sucrose media

    DEFF Research Database (Denmark)

    Katapodis, P.; Kalogeris, E.; Kekos, D.;

    2004-01-01

    Biosynthesis of fructo-oligosaccharides (FOS) was observed during growth of the thermophilic fungus Sporotrichum thermophile on media containing high sucrose concentrations. Submerged batch cultivation with the optimum initial sucrose concentration of 250 g/l allowed the production of 12.5 g FOS...

  18. Aerobic rice mechanization: techniques for crop establishment

    Science.gov (United States)

    Khusairy, K. M.; Ayob, H.; Chan, C. S.; Fauzi, M. I. Mohamed; Mohamad Fakhrul, Z. O.; Shahril Shah, G. S. M.; Azlan, O.; Rasad, M. A.; Hashim, A. M.; Arshad, Z.; E, E. Ibrahim; Saifulizan, M. N.

    2015-12-01

    Rice being the staple food crops, hundreds of land races in it makes the diversity of rice crops. Aerobic rice production was introduced which requires much less water input to safeguard and sustain the rice production and conserve water due to decreasing water resources, climatic changes and competition from urban and industrial users. Mechanization system plays an important role for the success of aerobic rice cultivation. All farming activities for aerobic rice production are run on aerobic soil conditions. Row seeder mechanization system is developed to replace conventional seeding technique on the aerobic rice field. It is targeted for small and the large scale aerobic rice farmers. The aero - seeder machine is used for the small scale aerobic rice field, while the accord - seeder is used for the large scale aerobic rice field. The use of this mechanization machine can eliminate the tedious and inaccurate seeding operations reduce labour costs and increases work rate. The machine is easy to operate and it can increase crop establishment rate. It reduce missing hill, increasing planting and crop with high yield can be produce. This machine is designed for low costs maintenance and it is easy to dismantle and assemble during maintenance and it is safe to be used.

  19. Skeletal Muscle Hypertrophy after Aerobic Exercise Training

    OpenAIRE

    Konopka, Adam R.; Harber, Matthew P.

    2014-01-01

    Current dogma suggests aerobic exercise training has minimal effect on skeletal muscle size. We and others have demonstrated that aerobic exercise acutely and chronically alters protein metabolism and induces skeletal muscle hypertrophy. These findings promote an antithesis to the status quo by providing novel perspective on skeletal muscle mass regulation and insight into exercise-countermeasures for populations prone to muscle loss.

  20. Comprehensive microbial analysis of combined mesophilic anaerobic-thermophilic aerobic process treating high-strength food wastewater

    DEFF Research Database (Denmark)

    Jang, Hyun Min; Ha, Jeong Hyub; Park, Jong Moon;

    2015-01-01

    organic matter removal efficiencies (over 90%) of TS, VS and COD and methane production than did R3. Quantitative real-time PCR (qPCR) results indicated that higher populations of both bacteria and archaea were maintained in R1 than in R3. Pyrosequencing analysis revealed relatively high abundance...

  1. Comparative genomic analysis of the thermophilic biomass-degrading fungi Myceliophthora thermophila and Thielavia terrestris.

    Science.gov (United States)

    Berka, Randy M; Grigoriev, Igor V; Otillar, Robert; Salamov, Asaf; Grimwood, Jane; Reid, Ian; Ishmael, Nadeeza; John, Tricia; Darmond, Corinne; Moisan, Marie-Claude; Henrissat, Bernard; Coutinho, Pedro M; Lombard, Vincent; Natvig, Donald O; Lindquist, Erika; Schmutz, Jeremy; Lucas, Susan; Harris, Paul; Powlowski, Justin; Bellemare, Annie; Taylor, David; Butler, Gregory; de Vries, Ronald P; Allijn, Iris E; van den Brink, Joost; Ushinsky, Sophia; Storms, Reginald; Powell, Amy J; Paulsen, Ian T; Elbourne, Liam D H; Baker, Scott E; Magnuson, Jon; Laboissiere, Sylvie; Clutterbuck, A John; Martinez, Diego; Wogulis, Mark; de Leon, Alfredo Lopez; Rey, Michael W; Tsang, Adrian

    2011-10-02

    Thermostable enzymes and thermophilic cell factories may afford economic advantages in the production of many chemicals and biomass-based fuels. Here we describe and compare the genomes of two thermophilic fungi, Myceliophthora thermophila and Thielavia terrestris. To our knowledge, these genomes are the first described for thermophilic eukaryotes and the first complete telomere-to-telomere genomes for filamentous fungi. Genome analyses and experimental data suggest that both thermophiles are capable of hydrolyzing all major polysaccharides found in biomass. Examination of transcriptome data and secreted proteins suggests that the two fungi use shared approaches in the hydrolysis of cellulose and xylan but distinct mechanisms in pectin degradation. Characterization of the biomass-hydrolyzing activity of recombinant enzymes suggests that these organisms are highly efficient in biomass decomposition at both moderate and high temperatures. Furthermore, we present evidence suggesting that aside from representing a potential reservoir of thermostable enzymes, thermophilic fungi are amenable to manipulation using classical and molecular genetics.

  2. Comparative genomic analysis of the thermophilic biomass-degrading fungi Myceliophthora thermophila and thielavia terrestris

    Energy Technology Data Exchange (ETDEWEB)

    Berka, Randy; Grigoriev, Igor V.; Otillar, Robert P.; Salamov, Asaf; Grimwood, Jane; Reid, Ian; Ishmael, Nadeeza; john, tricia; Darmond, Corinne; Moisan, Marie-Claude; Henrissat, Bernard; Coutinho, Pedro M.; Lombard, Vincent; Natvig, Donald O.; Lindquist, Erika; Schmutz, Jeremy; Lucas, Susan; Harris, Paul; Powlowski, Justin; Bellemare, Annie; Taylor, David; Butler, Gregory; de Vries, Ronald P.; Allijn, Iris E.; van den Brink, Joost; Ushinsky, Sophia; Storms, Reginald; Powell, Amy J.; Paulsen, Ian T.; Elbourne, Liam D. H.; Baker, Scott E.; Magnuson, Jon K.; LaBoissiere, Sylvie; Martinez, Diego; Wogulis, Mark; Lopez de Leon, Alfredo; Rey, Michael; Tsang, Adrian

    2011-10-02

    Thermostable enzymes and thermophilic cell factories may afford economic advantages in the production of many chemicals and biomass-based fuels. Here we describe and compare the genomes of two thermophilic fungi, Myceliophthora thermophila and Thielavia terrestris. To our knowledge, these genomes are the first described for thermophilic eukaryotes and the first complete telomere-to-telomere genomes for filamentous fungi. Genome analyses and experimental data suggest that both thermophiles are capable of hydrolyzing all major polysaccharides found in biomass. Examination of transcriptome data and secreted proteins suggests that the two fungi use shared approaches in the hydrolysis of cellulose and xylan but distinct mechanisms in pectin degradation. Characterization of the biomass-hydrolyzing activity of recombinant enzymes suggests that these organisms are highly efficient in biomass decomposition at both moderate and high temperatures. Furthermore, we present evidence suggesting that aside from representing a potential reservoir of thermostable enzymes, thermophilic fungi are amenable to manipulation using classical and molecular genetics.

  3. Comparative genomic analysis of the thermophilic biomass-degrading fungi Myceliophthora thermophila and Thielavia terrestris

    Energy Technology Data Exchange (ETDEWEB)

    Berka, Randy M.; Grigoriev, Igor V.; Otillar, Robert; Salamov, Asaf; Grimwood, Jane; Reid, Ian; Ishmael, Nadeeza; John, Tricia; Darmond, Corinne; Moisan, Marie-Claude; Henrissat, Bernard; Coutinho, Pedro M.; Lombard, Vincent; Natvig, Donald O.; Lindquist, Erika; Schmutz, Jeremy; Lucas, Susan; Harris, Paul; Powlowski, Justin; Bellemare, Annie; Taylor, David; Butler, Gregory; de Vries, Ronald P.; Allijn, Iris E.; van den Brink, Joost; Ushinsky, Sophia; Storms, Reginald; Powell, Amy J.; Paulsen, Ian T.; Elbourne, Liam D. H.; Baker, Scott. E.; Magnuson, Jon; LaBoissiere, Sylvie; Clutterbuck, A. John; Martinez, Diego; Wogulis, Mark; Lopez de Leon, Alfredo; Rey, Michael W.; Tsang, Adrian

    2011-05-16

    Thermostable enzymes and thermophilic cell factories may afford economic advantages in the production of many chemicals and biomass-based fuels. Here we describe and compare the genomes of two thermophilic fungi, Myceliophthora thermophila and Thielavia terrestris. To our knowledge, these genomes are the first described for thermophilic eukaryotes and the first complete telomere-to-telomere genomes for filamentous fungi. Genome analyses and experimental data suggest that both thermophiles are capable of hydrolyzing all major polysaccharides found in biomass. Examination of transcriptome data and secreted proteins suggests that the two fungi use shared approaches in the hydrolysis of cellulose and xylan but distinct mechanisms in pectin degradation. Characterization of the biomass-hydrolyzing activity of recombinant enzymes suggests that these organisms are highly efficient in biomass decomposition at both moderate and high temperatures. Furthermore, we present evidence suggesting that aside from representing a potential reservoir of thermostable enzymes, thermophilic fungi are amenable to manipulation using classical and molecular genetics.

  4. Gold on Different Manganese Oxides : Ultra-Low-Temperature CO Oxidation over Colloidal Gold Supported on Bulk-MnO2 Nanomaterials

    NARCIS (Netherlands)

    Gu, Dong; Tseng, Jo-Chi; Weidenthaler, Claudia; Bongard, Hans-Josef; Spliethoff, Bernd; Schmidt, Wolfgang; Soulimani, Fouad; Weckhuysen, Bert M; Schüth, Ferdi

    2016-01-01

    Nanoscopic gold particles have gained very high interest because of their promising catalytic activity for various chemicals reactions. Among these reactions, low-temperature CO oxidation is the most extensively studied one due to its practical relevance in environmental applications and the fundame

  5. Selection and Evaluation of Reference Genes for Reverse Transcription-Quantitative PCR Expression Studies in a Thermophilic Bacterium Grown under Different Culture Conditions.

    Directory of Open Access Journals (Sweden)

    Kathleen D Cusick

    Full Text Available The phylum Deinococcus-Thermus is a deeply-branching lineage of bacteria widely recognized as one of the most extremophilic. Members of the Thermus genus are of major interest due to both their bioremediation and biotechnology potentials. However, the molecular mechanisms associated with these key metabolic pathways remain unknown. Reverse-transcription quantitative PCR (RT-qPCR is a high-throughput means of studying the expression of a large suite of genes over time and under different conditions. The selection of a stably-expressed reference gene is critical when using relative quantification methods, as target gene expression is normalized to expression of the reference gene. However, little information exists as to reference gene selection in extremophiles. This study evaluated 11 candidate reference genes for use with the thermophile Thermus scotoductus when grown under different culture conditions. Based on the combined stability values from BestKeeper and NormFinder software packages, the following are the most appropriate reference genes when comparing: (1 aerobic and anaerobic growth: TSC_c19900, polA2, gyrA, gyrB; (2 anaerobic growth with varied electron acceptors: TSC_c19900, infA, pfk, gyrA, gyrB; (3 aerobic growth with different heating methods: gyrA, gap, gyrB; (4 all conditions mentioned above: gap, gyrA, gyrB. The commonly-employed rpoC does not serve as a reliable reference gene in thermophiles, due to its expression instability across all culture conditions tested here. As extremophiles exhibit a tendency for polyploidy, absolute quantification was employed to determine the ratio of transcript to gene copy number in a subset of the genes. A strong negative correlation was found to exist between ratio and threshold cycle (CT values, demonstrating that CT changes reflect transcript copy number, and not gene copy number, fluctuations. Even with the potential for polyploidy in extremophiles, the results obtained via absolute

  6. Biodegradation of Aliphatic-aromatic Coplyester under Thermophilic Conditions

    Directory of Open Access Journals (Sweden)

    Elsayed B. Belal

    2013-11-01

    Full Text Available The biodegradation of poly (tetramethylene adipate-co-tetramethylene terephthalate (BTA-copolyester as synthetic polyester was investigated under thermophilic conditions. Two efficient BTA degrading actinomycetes were isolated from compost at thermophilic phase. These strains were identified as Thermobifida fusca and Thermobispora bispora. The degradation rate for BTA films within 7 days was 17.12 and 16.96 mg/week.cm2 by T. fusca and T. bispora, respectively. The optimum BTA40:60 degradation conditions are obtained as pH7 and 55°C. The both strains exhibited a wider substrate spectrum as they are able to degrade synthetic polyesters (BTA40:60, PCL-S MaterBi ZF03U/A and natural polymers (poly-&beta-hydroxybutyric acid (PHB and carboxymethyl cellulose. It was shown that the extracellular hydrolyases activity from the both strains was induced in the presence of BTA-copolyester, while the presence of additional carbon sources such as glucose or a complex medium suppressed enzyme formation. Tributyrin as triglycerides was degraded by the both crude concentrated BTA-hydrolases. In contrast the enzyme was not capable to depolymerize the natural polymers PHB and carboxymethyl cellulose, although the organism itself degraded both types of polymers. The obtained results showed that the degradation rate with T. fusca BTA40:60-hydrolase was 3.67 mg/day.cm2 and was 3.5 mg/day.cm2 with T. bispora BTA40:60-hydrolase. The pH optimum for BTA-hydrolases was 7 with 20 and 100 mM phosphate buffer and it was 6 with 150 mM citrate buffer. Finally, it could be concluded that actinomycetes and their hydrolases play an outstanding role in recycling of biodegradable plastics under thermophilic phase during composting process.

  7. Abiotic and microbiotic factors controlling biofilm formation by thermophilic sporeformers.

    Science.gov (United States)

    Zhao, Yu; Caspers, Martien P M; Metselaar, Karin I; de Boer, Paulo; Roeselers, Guus; Moezelaar, Roy; Nierop Groot, Masja; Montijn, Roy C; Abee, Tjakko; Kort, Remco

    2013-09-01

    One of the major concerns in the production of dairy concentrates is the risk of contamination by heat-resistant spores from thermophilic bacteria. In order to acquire more insight in the composition of microbial communities occurring in the dairy concentrate industry, a bar-coded 16S amplicon sequencing analysis was carried out on milk, final products, and fouling samples taken from dairy concentrate production lines. The analysis of these samples revealed the presence of DNA from a broad range of bacterial taxa, including a majority of mesophiles and a minority of (thermophilic) spore-forming bacteria. Enrichments of fouling samples at 55°C showed the accumulation of predominantly Brevibacillus and Bacillus, whereas enrichments at 65°C led to the accumulation of Anoxybacillus and Geobacillus species. Bacterial population analysis of biofilms grown using fouling samples as an inoculum indicated that both Anoxybacillus and Geobacillus preferentially form biofilms on surfaces at air-liquid interfaces rather than on submerged surfaces. Three of the most potent biofilm-forming strains isolated from the dairy factory industrial samples, including Geobacillus thermoglucosidans, Geobacillus stearothermophilus, and Anoxybacillus flavithermus, have been characterized in detail with respect to their growth conditions and spore resistance. Strikingly, Geobacillus thermoglucosidans, which forms the most thermostable spores of these three species, is not able to grow in dairy intermediates as a pure culture but appears to be dependent for growth on other spoilage organisms present, probably as a result of their proteolytic activity. These results underscore the importance of abiotic and microbiotic factors in niche colonization in dairy factories, where the presence of thermophilic sporeformers can affect the quality of end products. PMID:23851093

  8. DECENTRALIZED THERMOPHILIC BIOHYDROGEN: A MORE EFFICIENT AND COST EFFECTIVE PROCESS

    Directory of Open Access Journals (Sweden)

    Rajesh K. Sani

    2011-11-01

    Full Text Available Nonfood lignocellulosic biomass is an ideal substrate for biohydrogen production. By avoiding pretreatment steps (acid, alkali, or enzymatic, there is potential to make the process economical. Utilization of regional untreated lignocellulosic biomass by cellulolytic and fermentative thermophiles in a consolidated mode using a single reactor is one of the ways to achieve economical and sustainable biohydrogen production. Employing these potential microorganisms along with decentralized biohydrogen energy production will lead us towards regional and national independence having a positive influence on the bioenergy sector.

  9. Extremely thermophilic microorganisms and their polymer-hidrolytic enzymes

    Directory of Open Access Journals (Sweden)

    Andrade Carolina M.M.C.

    1999-01-01

    Full Text Available Thermophilic and hyperthermophilic microorganisms are found as normal inhabitants of continental and submarine volcanic areas, geothermally heated sea-sediments and hydrothermal vents and thus are considered extremophiles. Several present or potential applications of extremophilic enzymes are reviewed, especially polymer-hydrolysing enzymes, such as amylolytic and hemicellulolytic enzymes. The purpose of this review is to present the range of morphological and metabolic features among those microorganisms growing from 70oC to 100°C and to indicate potential opportunities for useful applications derived from these features.

  10. Iron-embedded C2N monolayer: a promising low-cost and high-activity single-atom catalyst for CO oxidation.

    Science.gov (United States)

    He, B L; Shen, J S; Tian, Z X

    2016-09-21

    An Fe-embedded C2N monolayer as a promising single-atom catalyst for CO oxidation by O2 has been investigated based on first-principles calculations. It is found that the single Fe atom can be strongly trapped in the cavity of the C2N monolayer with a large adsorption energy of 4.55 eV and a high diffusion barrier of at least 3.00 eV to leave the cavity, indicating that Fe should exist in the isolated single-atom form. Due to the localized metal 3d orbitals near the Fermi level, the embedded Fe single-atom catalyst has a high chemical activity for the adsorption of CO and O2 molecules. CO oxidation by O2 on the catalyst would proceed via a two-step mechanism. The first step of the CO oxidation reaction has been studied via the Langmuir-Hinshelwood and Eley-Rideal mechanisms with energy barriers of 0.46 and 0.65 eV, respectively. The second step of the CO oxidation reaction follows the Eley-Rideal mechanism with a much smaller energy barrier of 0.24 eV. For both the steps, the CO2 molecules produced are weakly adsorbed on the substrates, suggesting that the proposed catalyst will not be poisoned by the generated CO2. Our results indicate that the Fe-embedded C2N monolayer is a promising single-atom catalyst for CO oxidation by O2 at low temperatures.

  11. Phytotoxicity Evolution of Biowastes Undergoing Aerobic Decomposition

    OpenAIRE

    M. R. Soares; Matsinhe, C.; Belo, S; M. J. Quina; Quinta-Ferreira, R.

    2013-01-01

    This study is mainly focused on the phytotoxicity improvement within five to six weeks of thermophilic composting of biowastes. Two sets of experiments were conducted involving both sawdust and rice husk as bulking agents, which were composted in self-heating reactors with potato-peel industrial waste and grass clippings as organic materials. The main variables observed over time were temperature, oxygen uptake rate (OUR), biodegradability, and germination index (GI). The effects of compo...

  12. Low aerobic fitness in Brazilian adolescents

    Directory of Open Access Journals (Sweden)

    Diego Augusto Santos Silva

    2015-04-01

    Full Text Available INTRODUCTION: aerobic fitness is considered one of the most important components of health-related physical fitness, with low levels related to increased risk of premature death from all causes, especially cardiovascular diseases. OBJECTIVE: to identify the characteristics of adolescents at higher risk of low levels of aerobic fitness. METHODS: the study included 696 adolescents 15-17 years of age enrolled in public high schools of Florianópolis, southern Brazil. This cross-sectional epidemiological study was conducted in Florianópolis, Santa Catarina, Brazil. Aerobic fitness was measured using the modified Canadian Aerobic Fitness Test mCAFT. Sociodemographic gender, age, school grade, paternal and maternal schooling, socioeconomic status, and anthropometric variables body weight, height, triceps and subscapular skinfold thickness, sexual maturation, physical activity, sedentary behavior, and eating habits were collected. RESULTS: it was found that 31.5% of adolescents had low aerobic fitness levels, being higher in boys 49.2% compared to girls 20.6%. Moreover, girls with sedentary behavior, overweight and high body fat percentage were the groups most likely to have inadequate aerobic fitness. In males, the groups most likely to have inadequate aerobic fitness were those whose parents studied more than eight years, those with low levels of physical activity, and those with inadequate nutrition and excessive body fat. CONCLUSION: low aerobic fitness levels were present in one third of adolescents and was more prevalent in boys. Lifestyle changes, including replacement of sedentary behaviors by physical and sport activities , may assist in improving the aerobic fitness of Brazilian adolescents.

  13. Bioleaching of chalcopyrite by mixed culture of moderately thermophilic microorganisms

    Institute of Scientific and Technical Information of China (English)

    WU Chang-bin; ZENG Wei-min; ZHOU Hong-bo; FU Bo; HUANG Ju-fang; QIU Guan-zhou; WANG Dian-zuo

    2007-01-01

    A mixed culture of moderately thermophilic microorganisms was enriched from acid mine drainages(AMDs) samples collected from several sulphide mines in China, and the bioleaching of chalcopyrite was conducted both in shake flask and bioreactor.The results show that in the shake flask, the mixture can tolerate 50 g/L chalcopyrite after being acclimated to gradually increased concentrations of chalcopyrite. The copper extraction increases obviously in bioleaching of chalcopyrite with moderately thermophilic microorganisms supplemented with 0.4 g/L yeast extract at 180 r/min, 74% copper can be extracted in the pulp of 50 g/L chalcopyrite after 20 d. Compared with copper extractions of mesophilic culture, unacclimated culture and acclimated culture without addition of yeast extract, that of accliniated culture with addition of yeast extract is increased by 53%, 44% and 16%,respectively. In a completely stirred tank reactor, the mass fraction of copper and total iron extraction reach up to 81% and 56%,respectively. The results also indicate that it is necessary to add a large amount of acid to the pulp to extract copper from chalcopyrite effectively.

  14. Hydrolytic bacteria in mesophilic and thermophilic degradation of plant biomass

    Energy Technology Data Exchange (ETDEWEB)

    Zverlov, Vladimir V.; Hiegl, Wolfgang; Koeck, Daniela E.; Koellmeier, Tanja; Schwarz, Wolfgang H. [Department of Microbiology, Technische Universitaet Muenchen, Freising-Weihenstephan (Germany); Kellermann, Josef [Max Planck Institute for Biochemistry, Am Klopferspitz, Martinsried (Germany)

    2010-12-15

    Adding plant biomass to a biogas reactor, hydrolysis is the first reaction step in the chain of biological events towards methane production. Maize silage was used to enrich efficient hydrolytic bacterial consortia from natural environments under conditions imitating those in a biogas plant. At 55-60 C a more efficient hydrolyzing culture could be isolated than at 37 C. The composition of the optimal thermophilic bacterial consortium was revealed by sequencing clones from a 16S rRNA gene library. A modified PCR-RFLP pre-screening method was used to group the clones. Pure anaerobic cultures were isolated. 70% of the isolates were related to Clostridium thermocellum. A new culture-independent method for identification of cellulolytic enzymes was developed using the isolation of cellulose-binding proteins. MALDI-TOF/TOF analysis and end-sequencing of peptides from prominent protein bands revealed cellulases from the cellulosome of C. thermocellum and from a major cellulase of Clostridium stercorarium. A combined culture of C. thermocellum and C. stercorarium was shown to excellently degrade maize silage. A spore preparation method suitable for inoculation of maize silage and optimal hydrolysis was developed for the thermophilic bacterial consortium. This method allows for concentration and long-term storage of the mixed culture for instance for inoculation of biogas fermenters. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Report: antibiotic production by thermophilic Bacillus specie SAT-4.

    Science.gov (United States)

    Muhammad, Syed Aun; Ahmad, Safia; Hameed, Abdul

    2009-07-01

    Production of antimicrobial compounds seems to be a general phenomenon for most bacteria. The prevalence of antimicrobial resistance among key microbial pathogens is increasing at an alarming rate worldwide. Current solutions involve development of a more rationale approach to antibiotic use and discover of new antimicrobials. Bacillus species produce a large number of biological compounds active against bacteria, fungi, protozoa and viruses. The process of production usually involves screening of wide range of microorganisms, testing and modification. Production is carried out using fermentation. Thermophilic spore-forming, gram positive, motile rod bacterial strains were isolated from the Thar Desserts, Sindh Province, Pakistan. These strains were screened and checked for antibacterial activity. The best activity was observed by SAT4 against Micrococcus luteus, Staphylococcus aureus and Pseudomonas aeroginosa. The activity was only observed against gram positive bacteria and no activity was seen against Pseudomonas aeroginosa. Thermophilic Bacillus specie SAT4 was found to be active in the fermentation process to produce the antimicrobial agents. Further optimizations of different conditions (time of incubation, media, pH, glucose concentrations, nitrogen concentrations, and temperature) for antimicrobial production by the selected bacterial strain was performed. Agar diffusion assay was performed to evaluate the antibacterial activity. Optimum conditions for the production of antimicrobials by selected isolate were observed to be 48 hour, pH 5, temperature 55 degrees C, 2% glucose and 1.5% nitrogen concentration. This newly isolated bacterial strain has great potential for antimicrobial production at industrial scale. PMID:19553186

  16. Biomass production and energy source of thermophiles in a Japanese alkaline geothermal pool.

    Science.gov (United States)

    Kimura, Hiroyuki; Mori, Kousuke; Nashimoto, Hiroaki; Hattori, Shohei; Yamada, Keita; Koba, Keisuke; Yoshida, Naohiro; Kato, Kenji

    2010-02-01

    Microbial biomass production has been measured to investigate the contribution of planktonic bacteria to fluxations in dissolved organic matter in marine and freshwater environments, but little is known about biomass production of thermophiles inhabiting geothermal and hydrothermal regions. The biomass production of thermophiles inhabiting an 85 degrees C geothermal pool was measured by in situ cultivation using diffusion chambers. The thermophiles' growth rates ranged from 0.43 to 0.82 day(-1), similar to those of planktonic bacteria in marine and freshwater habitats. Biomass production was estimated based on cellular carbon content measured directly from the thermophiles inhabiting the geothermal pool, which ranged from 5.0 to 6.1 microg C l(-1) h(-1). This production was 2-75 times higher than that of planktonic bacteria in other habitats, because the cellular carbon content of the thermophiles was much higher. Quantitative PCR and phylogenetic analysis targeting 16S rRNA genes revealed that thermophilic H2-oxidizing bacteria closely related to Calderobacterium and Geothermobacterium were dominant in the geothermal pool. Chemical analysis showed the presence of H2 in gases bubbling from the bottom of the geothermal pool. These results strongly suggested that H2 plays an important role as a primary energy source of thermophiles in the geothermal pool.

  17. Knowledge-based discovery for designing CRISPR-CAS systems against invading mobilomes in thermophiles.

    Science.gov (United States)

    Chellapandi, P; Ranjani, J

    2015-09-01

    Clustered regularly interspaced short palindromic repeats (CRISPRs) are direct features of the prokaryotic genomes involved in resistance to their bacterial viruses and phages. Herein, we have identified CRISPR loci together with CRISPR-associated sequences (CAS) genes to reveal their immunity against genome invaders in the thermophilic archaea and bacteria. Genomic survey of this study implied that genomic distribution of CRISPR-CAS systems was varied from strain to strain, which was determined by the degree of invading mobiloms. Direct repeats found to be equal in some extent in many thermopiles, but their spacers were differed in each strain. Phylogenetic analyses of CAS superfamily revealed that genes cmr, csh, csx11, HD domain, devR were belonged to the subtypes of cas gene family. The members in cas gene family of thermophiles were functionally diverged within closely related genomes and may contribute to develop several defense strategies. Nevertheless, genome dynamics, geological variation and host defense mechanism were contributed to share their molecular functions across the thermophiles. A thermophilic archaean, Thermococcus gammotolerans and thermophilic bacteria, Petrotoga mobilis and Thermotoga lettingae have shown superoperons-like appearance to cluster cas genes, which were typically evolved for their defense pathways. A cmr operon was identified with a specific promoter in a thermophilic archaean, Caldivirga maquilingensis. Overall, we concluded that knowledge-based genomic survey and phylogeny-based functional assignment have suggested for designing a reliable genetic regulatory circuit naturally from CRISPR-CAS systems, acquired defense pathways, to thermophiles in future synthetic biology.

  18. How "healthful" are aerobics classes? Exploring the health and wellness messages in aerobics classes for women.

    Science.gov (United States)

    D'Abundo, Michelle Lee

    2007-01-01

    The purpose of this study was to explore the health messages communicated by aerobics instructors in aerobics classes for women. A theoretical framework influenced by adult learning theory and feminist pedagogy was used in this qualitative study. Over a 3-month period, the practices of five aerobics instructors working at one nonprofit fitness center and one wellness facility were explored. The methods of data collection were one interview with each aerobics instructor and 14 site visits to conduct participant observations and to retrieve of documents. Despite the nonprofit and wellness-based environment of the exercise facilities in this research, there was still an overemphasis on the physical aspect of aerobics classes. Therefore, the potential wellness-related benefits of aerobics classes for women, especially in environments that identified themselves as promoting wellness, were not fully realized. PMID:17148107

  19. Synthesis of LaxK1-xCoO3 nanorod and their catalytic performances for CO oxidation

    Institute of Scientific and Technical Information of China (English)

    刘坚; 王季秋; 赵震; 徐春明; 韦岳长; 段爱军; 姜桂元

    2014-01-01

    A series of LaxK1-xCoO3 nanorod oxides with perovskite structure were synthesized by sol-gel method using polyvinyl al-cohol (PVA) as additive. These perovskite-type complex oxide catalysts were characterized by the techniques of X-ray diffraction (XRD), infrared (IR), Brumauer-Emmett-Teller (BET) and scanning electron microscopy (SEM). And the results showed that nano-rods of La1-xKxCoO3 perovskite-type complex oxides were fabricated by sol-gel method when the mass concentration of PVA was 4%and the calcined temperature kept at 700 ℃ for 4 h. The catalytic results of CO oxidation showed that the LaxK1-xCoO3 catalysts had high activity. LaCoO3 nanorods exposed more{110}plane than LaCoO3 nanoparticles, which was beneficial to the catalytic oxi-dation of CO. LaCoO3 nanorods had the best catalytic performance for the oxidation of CO. At 200 ºC, the CO conversion could reach 100%.

  20. Pollution Control Meets Sustainability: Structure-Activity Studies on New Iron Oxide-Based CO Oxidation Catalysts.

    Science.gov (United States)

    Schoch, Roland; Bauer, Matthias

    2016-08-01

    A new class of catalysts for the oxidation of CO based on iron oxide as a biocompatible, earth-abundant and non-toxic metal is presented. The catalytic activities achieved with these catalysts provide promising milestones towards the substitution of noble metals in CO oxidation catalysts. The catalysts can be obtained by using iron core-shell nanoparticle precursors. The metal used for the shell material determines whether the iron core is integrated in or isolated from the support. The active iron site is effectively integrated into the γ-Al2 O3 support if an aluminum shell is present in the core-shell precursor. When the metal used for the shell is different from the support, an isolated structure is formed. Using this directed synthesis approach, different iron oxide species can be obtained and their structural differences are linked to distinct catalytic activities, as demonstrated by combined in-depth analytical studies using XRD, X-ray absorption spectroscopy (XAS), UV/Vis, and Brunauer-Emmett-Teller (BET) analysis. The key species responsible for high catalytic activity is identified as isolated tetrahedrally coordinated Fe(III) centers, whereas aggregation leads to a reduction in activity. PMID:27440425

  1. CO oxidation on CuO/CeO{sub 2} catalyst prepared by solvothermal synthesis: influence of catalyst activation temperature

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Yuling; Mao, Dongsen, E-mail: dsmao@sit.edu.cn; Sun, Shuaishuai; Fu, Guangying [Shanghai Institute of Technology, Research Institute of Applied Catalysis, School of Chemical and Environmental Engineering (China)

    2015-12-15

    A series of CuO/CeO{sub 2} catalysts were prepared using a solvothermal method and a subsequent activation process. The influences of activation temperature (300–600 °C) on physicochemical properties and catalytic behavior of the prepared CuO/CeO{sub 2} catalysts have been investigated by XRD, SEM, Raman spectroscopy, S{sub BET} measurement, XPS surface analysis, H{sub 2}-TPR, CO-TPD techniques, and CO oxidation testing. The catalyst activated at 450 °C was found to have the highest catalytic activity, which can be ascribed to its higher dispersion of Cu species, higher concentration of oxygen vacancies, and larger amount of more active lattice oxygen. The lower activity of the CuO/CeO{sub 2} catalysts activated at lower (<450 °C) and higher (>450 °C) temperatures are attributed to the weaker interaction between CuO and CeO{sub 2}, and to the sintering of CuO nanoparticles, respectively.

  2. CO oxidation catalyzed by the single Co atom embedded hexagonal boron nitride nanosheet: a DFT-D study.

    Science.gov (United States)

    Lu, Zhansheng; Lv, Peng; Liang, Yanli; Ma, Dongwei; Zhang, Yi; Zhang, Wenjin; Yang, Xinwei; Yang, Zongxian

    2016-08-21

    A single metal atom stabilized on two dimensional materials (such as graphene and h-BN) exhibits extraordinary activity in the oxidation of CO. The oxidation of CO by molecular O2 on a single cobalt atom embedded in a hexagonal boron nitride monolayer (h-BN) is investigated using first-principles calculations with dispersion-correction. It is found that the single Co atom prefers to reside in a boron vacancy and possesses great stability. There are three mechanisms for CO oxidation: the traditional Eley-Rideal (ER) and Langmuir-Hinshelwood (LH) mechanisms and the termolecular Eley-Rideal (TER) mechanism proposed recently. Given the relatively small reaction barriers of the rate-limiting steps for the ER, LH and TER mechanisms (0.59, 0.55 and 0.41 eV, respectively), all three mechanisms are able to occur at low temperature. The current study may provide useful clues to develop low cost single atom catalysts. PMID:27436673

  3. Synthesis, Characterization and Shape-Dependent Catalytic CO Oxidation Performance of Ruthenium Oxide Nanomaterials: Influence of Polymer Surfactant

    Directory of Open Access Journals (Sweden)

    Antony Ananth

    2015-08-01

    Full Text Available Ruthenium oxide nano-catalysts supported on mesoporous γ-Al2O3 have been prepared by co-precipitation method and tested for CO oxidation. The effect of polyethylene glycol (PEG on the properties of the catalyst was studied. Addition of the PEG surfactant acted as a stabilizer and induced a change in the morphology of ruthenium oxide from spherical nanoparticles to one-dimensional nanorods. Total CO conversion was measured as a function of morphology at 175 °C and 200 °C with 1.0 wt.% loading for PEG-stabilized and un-stabilized catalysts, respectively. Conversion routinely increased with temperature but in each case, the PEG-stabilized catalyst exhibited a notably higher catalytic activity as compared to the un-stabilized equivalent. It can be assumed that the increase in the activity is due to the changes in porosity, shape and dispersion of the catalyst engendered by the use of PEG.

  4. Combinations of synergistic interactions and additive behavior during the co-oxidation of chars from lignite and biomass

    Energy Technology Data Exchange (ETDEWEB)

    Haykiri-Acma, H.; Yaman, S. [Istanbul Technical University, Chemical and Metallurgical Engineering Faculty, Chemical Engineering Department, 34469, Maslak, Istanbul (Turkey)

    2008-02-15

    The aim of this study is to investigate the co-combustion behavior of two different pyrolytic chars. For this purpose, Elbistan lignite and woody shells of hazelnut were pyrolysed in a tube furnace by heating to 900 C with a heating rate of 40 C min{sup -} {sup 1} under dynamic nitrogen flow of 400 mL min{sup -} {sup 1} to obtain pyrolytic char. These chars were mixed to obtain blends having the biomass char in the ratios of 5, 10, and 20 wt.%. Non-isothermal DTA and TGA profiles of the chars were obtained from ambient to 900 C with a heating rate of 40 C min{sup -} {sup 1} under the static ambient atmosphere. DTA and TGA profiles of the blend chars were interpreted considering the thermal characteristics such as ignition point, burnout at a given temperature, maximum burning rate, the end of combustion etc. Relations between the fraction of the biomass char in the blends and the thermal behavior of the blends were evaluated according to the synergistic approach. It was found that addition of biomass char led to important variations in some thermal properties which can not be explained by the additive behavior. However it can be concluded in general that the combinations of synergistic interactions and additive behavior govern the thermal properties of the blend chars during co-oxidation. (author)

  5. A comparative theoretical study of CO oxidation reaction by O2 molecule over Al- or Si-decorated graphene oxide.

    Science.gov (United States)

    Esrafili, Mehdi D; Sharifi, Fahimeh; Nematollahi, Parisa

    2016-09-01

    Using density functional theory calculations, the probable CO oxidation reaction mechanisms are investigated over Al- or Si-decorated graphene oxide (GO). The equilibrium geometry and electronic structure of these metal decorated-GOs along with the O2/CO adsorption configurations are studied in detail. The relatively large adsorption energies reveal that both Al and Si atoms can disperse on GO quite stably without clustering problem. Hence, both Al- and Si-decorated GOs are stable enough to be utilized in catalytic oxidation of CO by molecular O2. The two possible reaction pathways proposed for the oxidation of CO with O2 molecule are as follows: O2+CO→CO2+Oads and CO+Oads→CO2. The estimated energy barriers of the first oxidation reaction on Si-decorated GOs, following the Eley-Rideal (ER) reaction, are lower than that on Al-decorated ones. This is most likely due to the larger atomic charge on the Si atom than the Al one, which tends to stabilize the corresponding transition state structure. The results of this study can be useful for better understanding the chemical properties of Al- and Si-decorated GOs, and are valuable for the development of an automobile catalytic converter in order to remove the toxic CO molecule.

  6. Seedless Polyol Synthesis and CO Oxidation Activity of Monodisperse (111) and (100)-Oriented Rhodium Nanocrystals in Sub-10 nm Sizes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yawen; Grass, Michael E.; Huang, Wenyu; Somorjai, Gabor A.

    2010-03-15

    Monodisperse sub-10 nm (6.5 nm) sized Rh nanocrystals with (111) and (100) surface structures were synthesized by a seedless polyol reduction in ethylene glycol, with poly(vinylpyrrolidone) as a capping ligand. When using [Rh(Ac){sub 2}]{sub 2} as the metal precursor, (111)-oriented Rh nanopolyhedra containing 76% (111)-twined hexagons (in 2D projection) were obtained; whereas, when employing RhCl{sub 3} as the metal precursor in the presence of alkylammonium bromide, such as tetramethylammonium bromide and trimethyl(tetradecyl)ammonium bromide, (100)-oriented Rh nanocubes were obtained with 85% selectivity. The {l_brace}100{r_brace} faces of the Rh nanocrystals are stabilized by chemically adsorbed Br{sup -} ions from alkylammonium bromides, which led to (100)-oriented nanocubes. Monolayer films of the (111)-oriented Rh nanopolyhedra and (100)-oriented Rh nanocubes were deposited on silicon wafers in a Langmuir-Blodgett trough to make model 2D nanoarray catalysts. These nanocatalysts were active for CO oxidation by O{sub 2}, and the turnover frequency was independent of nanoparticle shape, consistent with that previously observed for Rh(111) and Rh(100) single crystals.

  7. Neuromodulation of Aerobic Exercise—A Review

    Directory of Open Access Journals (Sweden)

    Saskia eHeijnen

    2016-01-01

    Full Text Available Running, and aerobic exercise in general, is a physical activity that increasingly many people engage in but that also has become popular as a topic for scientific research. Here we review the available studies investigating whether and to which degree aerobic exercise modulates hormones, amino acids, and neurotransmitters levels. In general, it seems that factors such as genes, gender, training status, and hormonal status need to be taken into account to gain a better understanding of the neuromodular underpinnings of aerobic exercise. More research using longitudinal studies and considering individual differences is necessary to determine actual benefits. We suggest that, in order to succeed, aerobic exercise programs should include optimal periodization, prevent overtraining and be tailored to interindividual differences, including neuro-developmental and genetically-based factors.

  8. 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;

    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...... to the genera Bacillus and Clostridium. Relative abundance of the culture members, assessed by fluorescence in situ hybridization, were 87 +/- 5% and 13 +/- 5% for Bacillus and Clostridium, respectively. An extreme thermophilic, strict anaerobic, mixed microbial culture with H-2-producing potential was enriched...

  9. Collection of "strengthening sets" of aerobics lesson.\\\\

    OpenAIRE

    CAKL, Vojtěch

    2011-01-01

    The aim of this bachelor study was to create a strengthening sets for aerobic lessons including showing these possisions in practice on selective aerobic lessons . Based on special literature the author had chosen suitable muscle development exercises to increase the body strenth. These exercises were there practised for six weeks continuously. Before and after the research were selected individuals who were compared by 4 exact same tests to detect static and dynamic body strength. The result...

  10. Evaluation of A "Floating" Aerobics Floor

    OpenAIRE

    Favor, Craig M.

    1997-01-01

    Aerobics dance floors often produce annoying floor vibrations in adjacent parts of a building due to the rhythmic impact of the aerobicists. Various types of shock absorbing aerobics and dance floors are widely used to prevent injuries to the participants, but the floors may not prevent vibrations in adjacent areas of the building. The purpose of this investigation is to evaluate a temporary "floating" concrete a...

  11. Temperature effect on aerobic denitrification and nitrification

    Institute of Scientific and Technical Information of China (English)

    XIE Shu-guang; ZHANG Xiao-jian; WANG Zhan-sheng

    2003-01-01

    Nitrogen loss without organic removal in biofilter was observed and its possible reason was explained. A lower hydraulic loading could improve aerobic denitrification rate. Aerobic denitrification was seriously affected by low temperature(below 10oC). However, nitrification rate remained high when the temperature dropped from 15oC to5oC. It seemed the autotrophic biofilm in BAF could alleviate the adverse effect of low temperature.

  12. Enhanced in situ aerobic bioremediation

    Energy Technology Data Exchange (ETDEWEB)

    Sharfe, K. [CleanEARTH Solutions Ltd., Concord, ON (Canada)

    2007-07-01

    An enhanced in situ aerobic bioremediation process was described. The process used microbe supporting emulsifications to enhance bioavailability as well as to attenuate microbe competition and boost microbial production. Microbes were added prior to application and rapidly initiated bioremediation once applied to impacted areas. The microbe supporting emulsifiers were metabolically active. The study showed that exposed surface areas increased as hydrocarbon masses were divided, which in turn increased the water/substrate interface where microbial action occurred. Nutrients were used to ensure that crowding and waste accumulation were attenuated in order to ensure that the speed of growth and reproduction progressed exponentially. Water-carrying bacteria, enzymes and nutrients were adsorbed to the soil's particle surface and then diffused between particles. The sequestered hydrocarbons were then emulsified and removed in order to be bioremediated. It was concluded that biological catalysts were used to increase microbial activity and to trigger anabolic responses in microbes. Details of a biocatalyst laboratory solution analysis were also included. tabs., figs.

  13. Microbial community dynamics in thermophilic undefined milk starter cultures.

    Science.gov (United States)

    Parente, Eugenio; Guidone, Angela; Matera, Attilio; De Filippis, Francesca; Mauriello, Gianluigi; Ricciardi, Annamaria

    2016-01-18

    Model undefined thermophilic starter cultures were produced from raw milk of nine pasta-filata cheesemaking plants using a selective procedure based on pasteurization and incubation at high temperature with the objective of studying the microbial community dynamics and the variability in performances under repeated (7-13) reproduction cycles with backslopping. The traditional culture-dependent approach, based on random isolation and molecular characterization of isolates was coupled to the determination of pH and the evaluation of the ability to produce acid and fermentation metabolites. Moreover, a culture-independent approach based on amplicon-targeted next-generation sequencing was employed. The microbial diversity was evaluated by 16S rRNA gene sequencing (V1-V3 regions), while the microdiversity of Streptococcus thermophilus populations was explored by using novel approach based on sequencing of partial amplicons of the phosphoserine phosphatase gene (serB). In addition, the occurrence of bacteriophages was evaluated by qPCR and by multiplex PCR. Although it was relatively easy to select for a community dominated by thermophilic lactic acid bacteria (LAB) within a single reproduction cycle, final pH, LAB populations and acid production activity fluctuated over reproduction cycles. Both culture-dependent and -independent methods showed that the cultures were dominated by either S. thermophilus or Lactobacillus delbrueckii subsp. lactis or by both species. Nevertheless, subdominant mesophilic species, including lactococci and spoilage organisms, persisted at low levels. A limited number of serB sequence types (ST) were present in S. thermophilus populations. L. delbrueckii and Lactococcus lactis bacteriophages were below the detection limit of the method used and high titres of cos type S. thermophilus bacteriophages were detected in only two cases. In one case a high titre of bacteriophages was concurrent with a S. thermophilus biotype shift in the culture

  14. Geometric and electronic structure of Au on Au/CeO2 catalysts during the CO oxidation: Deactivation by reaction induced particle growth

    Science.gov (United States)

    Abdel-Mageed, Ali M.; Kučerová, Gabriela; Abd El-Moemen, Ayman; Bansmann, Joachim; Widmann, Daniel; Jürgen Behm, R.

    2016-05-01

    Changes of the geometric and electronic structure of gold on Au/CeO2 catalysts induced by different pre-treatments (oxidative and reductive) and by the CO oxidation reaction at 80°C were followed by operando XANES / EXAFS measurements. The results showed that i) oxidative pre-treatment (O2) leads to larger Au nanoparticles than reductive pre-treatment (CO), that ii) Au is predominantly metallic during CO oxidation, irrespective of the preceding pre-treatment, and that iii) there is a reaction induced Au particle growth. Correlations with the activity of the respective catalysts and its temporal evolution give insights into the origin of deactivation of these catalysts under reaction conditions, in particular on reaction induced changes in the Au particle size.

  15. Catalytic activity of CuO-Gd0.1Ti0.1Zr0.1Ce0.7O2 in CO oxidation

    Indian Academy of Sciences (India)

    IGOR V ZAGAYNOV; ELENA YU LIBERMAN

    2016-06-01

    (1-10wt.%) CuO-Gd0.1Ti0.1Zr0.1Ce0.7O2 mesoporous catalysts were prepared by simple coprecipitationmethod with sonication and tested for CO oxidation. The catalysts show the highest activity dueto better dispersion of CuO species as well as enhanced interaction between CuO and the developed support. Itwas shown that these systems have full conversion at temperature of 60–65◦C.

  16. Effect of surface nanostructure on temperature programmed reaction spectroscopy: First-principles kinetic Monte Carlo simulations of CO oxidation at RuO2(110)

    OpenAIRE

    Rieger, M.(RWTH Aachen University, III. Physikalisches Institut A, Aachen, Germany); Rogal, J.; Reuter, K.

    2008-01-01

    Using the catalytic CO oxidation at RuO2(110) as a showcase, we employ first-principles kinetic Monte Carlo simulations to illustrate the intricate effects on temperature programmed reaction spectroscopy data brought about by the mere correlations between the locations of the active sites at a nanostructured surface. Even in the absence of lateral interactions, this nanostructure alone can cause inhomogeneities that cannot be grasped by prevalent mean-field data analysis procedures, which thu...

  17. Facile synthesis of PbTiO3 truncated octahedra via solid-state reaction and their application in low-temperature CO oxidation by loading Pt nanoparticles

    KAUST Repository

    Yin, Simin

    2014-01-01

    Perovskite PbTiO3 (PTO) nanocrystals with a truncated octahedral morphology have been prepared by a facile solid-state reaction. Pt nanoparticles preferentially nucleated on the {111} facet of PTO nanocrystals exhibit a remarkable low-temperature catalytic activity towards CO oxidation from a temperature as low as 30 °C and achieve 100% conversion at ∼50 °C. © 2014 the Partner Organisations.

  18. Carbohydrate utilization patterns for the extremely thermophilic bacterium Caldicellulosiruptor saccharolyticus reveal broad growth substrate preferences

    NARCIS (Netherlands)

    Vanfossen, A.L.; Verhaart, M.R.A.; Kengen, S.W.M.; Kelly, R.M.

    2009-01-01

    Co-utilization of hexoses and pentoses derived from lignocellulose is an attractive trait in microorganisms considered for consolidated biomass processing to biofuels. This issue was examined for the H2-producing, extremely thermophilic bacterium Caldicellulosiruptor saccharolyticus growing on indiv

  19. Pyrophosphate as a central energy carrier in the hydrogen-producing extremely thermophilic Caldicellulosiruptor saccharolyticus

    NARCIS (Netherlands)

    Bielen, A.A.M.; Willquist, K.; Engman, J.; Oost, van der J.; Niel, van E.W.J.; Kengen, S.W.M.

    2010-01-01

    The role of inorganic pyrophosphate (PPi) as an energy carrier in the central metabolism of the extremely thermophilic bacterium Caldicellulosiruptor saccharolyticus was investigated. In agreement with its annotated genome sequence, cell extracts were shown to exhibit PPi-dependent phosphofructokina

  20. Bioleaching of metals from electronic scrap by moderately thermophilic acidophilic bacteria

    NARCIS (Netherlands)

    Ilyas, Sadia; Anwar, Munir A.; Niazi, Shahida B.; Ghauri, M. Afzal

    2007-01-01

    The present work was aimed at studying the bioleachability of metals from electronic scrap by the selected moderately thermophilic strains of acidophilic chemolithotrophic and acidophilic heterotrophic bacteria. These included Sulfobacillus thermosulfidooxidans and an unidentified acidophilic hetero

  1. A novel membrane distillation-thermophilic bioreactor system: biological stability and trace organic compound removal.

    Science.gov (United States)

    Wijekoon, Kaushalya C; Hai, Faisal I; Kang, Jinguo; Price, William E; Guo, Wenshan; Ngo, Hao H; Cath, Tzahi Y; Nghiem, Long D

    2014-05-01

    The removal of trace organic compounds (TrOCs) by a novel membrane distillation-thermophilic bioreactor (MDBR) system was examined. Salinity build-up and the thermophilic conditions to some extent adversely impacted the performance of the bioreactor, particularly the removal of total nitrogen and recalcitrant TrOCs. While most TrOCs were well removed by the thermophilic bioreactor, compounds containing electron withdrawing functional groups in their molecular structure were recalcitrant to biological treatment and their removal efficiency by the thermophilic bioreactor was low (0-53%). However, the overall performance of the novel MDBR system with respect to the removal of total organic carbon, total nitrogen, and TrOCs was high and was not significantly affected by the conditions of the bioreactor. All TrOCs investigated here were highly removed (>95%) by the MDBR system. Biodegradation, sludge adsorption, and rejection by MD contribute to the removal of TrOCs by MDBR treatment. PMID:24658107

  2. Hydrogen production by hyperthermophilic and extremely thermophilic bacteria and archaea: mechanisms for reductant disposal

    NARCIS (Netherlands)

    Verhaart, M.R.A.; Bielen, A.A.M.; Oost, van der J.; Stams, A.J.M.; Kengen, S.W.M.

    2010-01-01

    Hydrogen produced from biomass by bacteria and archaea is an attractive renewable energy source. However, to make its application more feasible, microorganisms are needed with high hydrogen productivities. For several reasons, hyperthermophilic and extremely thermophilic bacteria and archaea are pro

  3. Physiological plasticity of the thermophilic ammonia oxidizing archaeon Nitrosocaldus yellowstonii in response to a changing environment

    Science.gov (United States)

    Jewell, T.; Johnson, A.; Gelsinger, D.; de la Torre, J. R.

    2012-12-01

    Our understanding of nitrogen biogeochemical cycling in high temperature environments underwent a dramatic revision with the discovery of ammonia oxidizing archaea (AOA). The importance of AOA to the global nitrogen cycle came to light when recent studies of marine AOA demonstrated the dominance of these organisms in the ocean microbiome and their role as producers of the greenhouse gas nitrous oxide (N2O). Understanding how AOA respond to fluctuating environments is crucial to fully comprehending their contribution to global biogeochemical cycling and climate change. In this study we use the thermophilic AOA Nitrosocaldus yellowstonii strain HL72 to explore the physiological plasticity of energy metabolism in these organisms. Previous studies have shown that HL72 grows autotrophically by aerobically oxidizing ammonia (NH3) to nitrite (NO2-). Unlike studies of marine AOA, we find that HL72 can grow over a wide ammonia concentration range (0.25 - 10 mM NH4Cl) with comparable generation times when in the presence of 0.25 to 4 mM NH4Cl. However, preliminary data indicate that amoA, the alpha subunit of ammonia monooxygenase (AMO), is upregulated at low ammonia concentrations (urea transporter. Urea ((NH2)2CO) is an organic compound ubiquitous to aquatic and soil habitats that, when hydrolyzed, forms NH3 and CO2. We examined urea as an alternate source of ammonia for the ammonia oxidation pathway. HL72 grows over a wide range of urea concentrations (0.25 - 10 mM) at rates comparable to growth on ammonia. In a substrate competition experiment HL72 preferentially consumed NH3 from NH4Cl when both substrates were provided in equal molar concentrations. However, the urease alpha subunit ureC was expressed in both the presence and absence of urea. One consequence of urea hydrolysis is consumption of intracellular protons during the reaction. As ammonia oxidation produces H+, leading to a decrease in pH, the hydrolysis of urea prior to ammonia oxidation may help alleviate

  4. Kinetic Monte Carlo Simulation of the oscillatory catalytic CO oxidation using a modified Ziff-Gulari-Barshad model

    Science.gov (United States)

    Sinha, Indrajit; Mukherjee, Ashim K.

    2014-03-01

    The oxidation of CO on Pt-group metal surfaces has attracted widespread attention since a long time due to its interesting oscillatory kinetics and spatiotemporal behavior. The use of STM in conjunction with other experimental data has confirmed the validity of the surface reconstruction (SR) model under low pressure and the more recent surface oxide (SO) model which is possible under sub-atmospheric pressure conditions [1]. In the SR model the surface is periodically reconstructed below a certain low critical CO-coverage and this reconstruction is lifted above a second, higher critical CO-coverage. Alternatively the SO model proposes periodic switching between a low-reactivity metallic surface and a high-reactivity oxide surface. Here we present an overview of our recent kinetic Monte Carlo (KMC) simulation studies on the oscillatory kinetics of surface catalyzed CO oxidation. Different modifications of the lattice gas Ziff-Gulari-Barshad (ZGB) model have been utilized or proposed for this purpose. First we present the effect of desorption on the ZGB reactive to poisoned irreversible phase transition in the SR model. Next we discuss our recent research on KMC simulation of the SO model. The ZGB framework is utilized to propose a new model incorporating not only the standard Langmuir-Hinshelwood (LH) mechanism, but also introducing the Mars-van Krevelen (MvK) mechanism for the surface oxide phase [5]. Phase diagrams, which are plots between long time averages of various oscillating quantities against the normalized CO pressure, show two or three transitions depending on the CO coverage critical threshold (CT) value beyond which all adsorbed oxygen atoms are converted to surface oxide.

  5. Gold on Different Manganese Oxides: Ultra-Low-Temperature CO Oxidation over Colloidal Gold Supported on Bulk-MnO2 Nanomaterials.

    Science.gov (United States)

    Gu, Dong; Tseng, Jo-Chi; Weidenthaler, Claudia; Bongard, Hans-Josef; Spliethoff, Bernd; Schmidt, Wolfgang; Soulimani, Fouad; Weckhuysen, Bert M; Schüth, Ferdi

    2016-08-01

    Nanoscopic gold particles have gained very high interest because of their promising catalytic activity for various chemicals reactions. Among these reactions, low-temperature CO oxidation is the most extensively studied one due to its practical relevance in environmental applications and the fundamental problems associated with its very high activity at low temperatures. Gold nanoparticles supported on manganese oxide belong to the most active gold catalysts for CO oxidation. Among a variety of manganese oxides, Mn2O3 is considered to be the most favorable support for gold nanoparticles with respect to catalytic activity. Gold on MnO2 has been shown to be significantly less active than gold on Mn2O3 in previous work. In contrast to these previous studies, in a comprehensive study of gold nanoparticles on different manganese oxides, we developed a gold catalyst on MnO2 nanostructures with extremely high activity. Nanosized gold particles (2-3 nm) were supported on α-MnO2 nanowires and mesoporous β-MnO2 nanowire arrays. The materials were extremely active at very low temperature (-80 °C) and also highly stable at 25 °C (70 h) under normal conditions for CO oxidation. The specific reaction rate of 2.8 molCO·h(-1)·gAu(-1) at a temperature as low as -85 °C is almost 30 times higher than that of the most active Au/Mn2O3 catalyst. PMID:27392203

  6. Importance of trivalency and the e(g)(1) configuration in the photocatalytic oxidation of water by Mn and Co oxides.

    Science.gov (United States)

    Maitra, Urmimala; Naidu, B S; Govindaraj, A; Rao, C N R

    2013-07-16

    Prompted by the early results on the catalytic activity of LiMn2O4 and related oxides in the photochemical oxidation of water, our detailed study of several manganese oxides has shown that trivalency of Mn is an important factor in determining the catalytic activity. Thus, Mn2O3, LaMnO3, and MgMn2O4 are found to be very good catalysts with turnover frequencies of 5 × 10(-4) s(-1), 4.8 × 10(-4) s(-1), and 0.8 × 10(-4) s(-1), respectively. Among the cobalt oxides, Li2Co2O4 and LaCoO3--especially the latter--exhibit excellent catalytic activity, with the turnover frequencies being 9 × 10(-4) s(-1) and 1.4 × 10(-3) s(-1), respectively. The common feature among the catalytic Mn and Co oxides is not only that Mn and Co are in the trivalent state, but Co(3+) in the Co oxides is in the intermediate t2g(5)e(g)(1) state whereas Mn(3+) is in the t2g(3e(g)(1) state. The presence of the e(g)(1) electron in these Mn and Co oxides is considered to play a crucial role in the photocatalytic properties of the oxides.

  7. Atmospheric-Pressure DBD Cold Plasma for Preparation of High Active Au/P25 Catalysts for Low-Temperature CO Oxidation

    Institute of Scientific and Technical Information of China (English)

    DI Lanbo; ZHAN Zhibin; ZHANG Xiuling; QI Bin; XU Weijie

    2016-01-01

    Cold plasma generated by dielectric barrier discharge (DBD) at atmospheric pressure was adopted for preparation of commercial TiO2 Degussa P25 supported Au catalysts (Au/P25-P) with the assistance of the deposition-precipitation procedure.The influences of the plasma reduction time and calcination on the performance of the Au/P25-P catalysts were investigated.CO oxidation was performed to investigate the catalytic activity of thc Au/P25 catalysts.The results show that DBD cold plasma for the fabrication of Au/P25-P catalysts is a fast process,and Au/P25-P (4 min) exhibited the highest CO oxidation activity due to the complete reduction of Au compounds and less consumption of oxygen vacancies.In order to form more oxygen vacancies active species,Au/P25-P was calcined to obtain Au/P25-PC catalysts.Interestingly,Au/P25-PC exhibited the highest activity for CO oxidation among the Au/P25 samples.The results of transmission electron microscopy (TEM) indicated that the smaller size and high distribution of Au nanoparticles are the mean reasons for a high performance of Au/P25-PC.Atmospheric-pressure DBD cold plasma was proved to be of great efficiency in preparing high performance supported Au catalysts.

  8. A high-throughput study of the redox properties of Nb-Ni oxide catalysts by low temperature CO oxidation: Implications in ethane ODH

    KAUST Repository

    Laveille, Paco

    2013-03-01

    CO oxidation is used as a probe reaction to evaluate the redox properties of catalysts for the low temperature oxidative dehydrogenation (ODH) of ethane. Three series of Nb1-x-NixO nanocomposites with various Nb contents (x = 1, 0.95, 0.90, 0.85, 0.80) are prepared by a sol-gel route based on citrate and tested in a 16 parallel fixed-bed unit. Reductive and oxidative pre-treatments are shown to influence both the activity and the stability of the catalysts in CO oxidation. The extent of this effect depends on the Nb content of the composites, the Nb-rich samples being generally the most affected. However, the order of reactivity in CO oxidation is the same for the three series and is maintained whatever the conditions of the pre-treatment. It is the same as that observed in Nb1-x-NixO-catalyzed ethane ODH. © 2012 Elsevier B.V. All rights reserved.

  9. Iridium ultrasmall nanoparticles, worm-like chain nanowires, and porous nanodendrites: One-pot solvothermal synthesis and catalytic CO oxidation activity

    Science.gov (United States)

    Zhang, Tao; Li, Shuai-Chen; Zhu, Wei; Ke, Jun; Yu, Jing-Wen; Zhang, Zhi-Ping; Dai, Lin-Xiu; Gu, Jun; Zhang, Ya-Wen

    2016-06-01

    We report a facile one-pot solvothermal synthesis of monodisperse iridium (Ir) ultrasmall (1.5-2.5 nm in diameter) nanoparticles (NPs), worm-like chain nanowires (NWs), and porous nanodendrites (NDs), for which CO oxidation reaction has been employed as a probe reaction to investigate the effects of nanoparticle size and surface-capping organics on the catalytic activities. Time-dependent experiments revealed that an oriented attachment mechanism induced by the strong adsorption of halide anions (Br- and I-) on specific facet of Ir nanoclusters or by decreasing the reduction rate of Ir precursors with changing their concentrations during the synthesis was responsible for the formation of Ir NWs and NDs. Annealing tests indicated that an O2-H2 atmosphere treatment turned out to be an effective measure to clean up the surface-capping organics of Ir NPs supported on commercial SiO2. Catalytic CO oxidation reaction illustrated that a significant improvement in the catalytic activity of CO oxidation reaction was achieved together with the changing of activation energies after such atmosphere treatment for the supported catalysts of the ultrasmall Ir NPs. It is noteworthy that this enhancement in catalytic activity could be ascribed to the changes in the surface status (including populations of Ir species in metallic and oxidized states, removal of surface capping organics, the variety of active sites, and total effective active site number) for the supported nanocatalysts during the atmosphere treatment.

  10. Synthesis of MnFe2O4@Mn-Co oxide core-shell nanoparticles and their excellent performance for heavy metal removal.

    Science.gov (United States)

    Ma, Zichuan; Zhao, Dongyuan; Chang, Yongfang; Xing, Shengtao; Wu, Yinsu; Gao, Yuanzhe

    2013-10-21

    Magnetic nanomaterials that can be easily separated and recycled due to their magnetic properties have received considerable attention in the field of water treatment. However, these nanomaterials usually tend to aggregate and alter their properties. Herein, we report an economical and environmentally friendly method for the synthesis of magnetic nanoparticles with core-shell structure. MnFe2O4 nanoparticles have been successfully coated with amorphous Mn-Co oxide shells. The synthesized MnFe2O4@Mn-Co oxide nanoparticles have highly negatively charged surface in aqueous solution over a wide pH range, thus preventing their aggregation and enhancing their performance for heavy metal cation removal. The adsorption isotherms are well fitted to a Langmuir adsorption model, and the maximal adsorption capacities of Pb(II), Cu(II) and Cd(II) on MnFe2O4@Mn-Co oxide are 481.2, 386.2 and 345.5 mg g(-1), respectively. All the metal ions can be completely removed from the mixed metal ion solutions in a short time. Desorption studies confirm that the adsorbent can be effectively regenerated and reused.

  11. Synthesis of MnFe2O4@Mn-Co oxide core-shell nanoparticles and their excellent performance for heavy metal removal.

    Science.gov (United States)

    Ma, Zichuan; Zhao, Dongyuan; Chang, Yongfang; Xing, Shengtao; Wu, Yinsu; Gao, Yuanzhe

    2013-10-21

    Magnetic nanomaterials that can be easily separated and recycled due to their magnetic properties have received considerable attention in the field of water treatment. However, these nanomaterials usually tend to aggregate and alter their properties. Herein, we report an economical and environmentally friendly method for the synthesis of magnetic nanoparticles with core-shell structure. MnFe2O4 nanoparticles have been successfully coated with amorphous Mn-Co oxide shells. The synthesized MnFe2O4@Mn-Co oxide nanoparticles have highly negatively charged surface in aqueous solution over a wide pH range, thus preventing their aggregation and enhancing their performance for heavy metal cation removal. The adsorption isotherms are well fitted to a Langmuir adsorption model, and the maximal adsorption capacities of Pb(II), Cu(II) and Cd(II) on MnFe2O4@Mn-Co oxide are 481.2, 386.2 and 345.5 mg g(-1), respectively. All the metal ions can be completely removed from the mixed metal ion solutions in a short time. Desorption studies confirm that the adsorbent can be effectively regenerated and reused. PMID:23945878

  12. Hetero-metal cation control of CuO nanostructures and their high catalytic performance for CO oxidation

    Science.gov (United States)

    Huang, Hongwen; Zhang, Liqiang; Wu, Kewei; Yu, Qing; Chen, Ru; Yang, Hangsheng; Peng, Xinsheng; Ye, Zhizhen

    2012-11-01

    A controllable synthesis of various morphologies of CuO nanostructures with tuning by hetero-metal cations has been developed in aqueous solution at room temperature. The morphologies of CuO can be engineered from nanosheets to nanoparticles with different length ratios of the long axis to the short axis. The formation of many metal-ion complexes plays an important role in slowing the release rate of OH- and affects the reaction kinetics further. We found that the effect of hetero-metal cations on the final morphology of the CuO nanostructures was the same as that of the cooling temperature. A series of temperature-controlled experiments demonstrated this. Furthermore, among all the synthesized CuO nanostructures, the fascinating colloidal mesoporous CuO quasi-monocrystalline nanosheets prepared at 25 °C with a thickness of ca. 10 nm and large specific surface area of 80.32 m2 g-1 is investigated intensively. These CuO nanosheets demonstrate a superior catalytic activity for CO oxidation, with features of high CO conversion efficiency (47.77 mmolCO g-1CuO h-1 at 200 °C), which is close to that reported for previously investigated supported-CuO catalysts, and a low apparent activation energy Ea (53.3 kJ mol-1).A controllable synthesis of various morphologies of CuO nanostructures with tuning by hetero-metal cations has been developed in aqueous solution at room temperature. The morphologies of CuO can be engineered from nanosheets to nanoparticles with different length ratios of the long axis to the short axis. The formation of many metal-ion complexes plays an important role in slowing the release rate of OH- and affects the reaction kinetics further. We found that the effect of hetero-metal cations on the final morphology of the CuO nanostructures was the same as that of the cooling temperature. A series of temperature-controlled experiments demonstrated this. Furthermore, among all the synthesized CuO nanostructures, the fascinating colloidal mesoporous Cu

  13. Genetics of thermophilic bacteria. [Bacillus stearothermophilus:a2

    Energy Technology Data Exchange (ETDEWEB)

    Welker, N.E.

    1991-01-01

    Organisms adapted to high temperature have evolved a variety of unique solutions to the biochemical problems imposed by this environment. Adaptation is commonly used to describe the biochemical properties of organisms which have become adapted to their environment (genetic adaptation). It can also mean the direct response-at the cellular level-of an organism to changes in temperature (physiological adaptation). Thermophilic bacilli (strains of Bacillus stearothermophilus) can exhibit a variety of biochemical adaptations in response to changes in temperature. These include changes in the composition and stability of the membrane, metabolic potential, the transport of amino acids, regulatory mechanisms, ribose methylation of tRNA, protein thermostability, and nutritional requirements. The objectives of the research were to develop efficient and reliable genetic systems to analyze and manipulate B. Stearothermophilus, and to use these systems initiate a biochemical, molecular, and genetic investigations of genes that are required for growth at high temperature.

  14. Characterization of a thermophilic bacteriophage of Geobacillus kaustophilus.

    Science.gov (United States)

    Marks, Timothy J; Hamilton, Paul T

    2014-10-01

    GBK2 is a bacteriophage, isolated from a backyard compost pile, that infects the thermophile Geobacillus kaustophilus. GBK2 has a circularly permuted genome of 39,078 bp with a G+C content of 43 %. Annotation of the genome reveals 62 putative open reading frames (ORFs), 25 of which (40.3 %) show homology to known proteins and 37 of which (59.7 %) are proteins with unknown functions. Twelve of the identified ORFs had the greatest homology to genes from the phage SPP1, a phage that infects the mesophile Bacillus subtilis. The overall genomic arrangement of GBK2 is similar to that of SPP1, with the majority of GBK2 SPP1-like genes coding for proteins involved in DNA replication and metabolism.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-09-16

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

  16. Ribotyping Identification of Thermophilic Bacterium from Papandayan Crater

    Directory of Open Access Journals (Sweden)

    Akhmaloka

    2006-05-01

    Full Text Available A few thermophilic bacteria were isolated from a hot spring located in Papandayan Crater, Garut. One of the organisms showed a well growth at temperature of up to 80oC. Chromosomal DNA from the organism was isolated and used to amplify 16S rRNA gene fragment. The gene was amplified by a set of universal primers (27F and 1492R resulting in a 1.5 kb DNA fragment. The gene was cloned and sequenced. The phylogenetic tree, homological analysis, and detailed comparison of the sequences showed that 16S rRNA gene sequence of the Papandayan isolate is unique compared to other known strains, however the sequence had closest similarities with Bacillus caldolyticus and Bacillus caldotenax.

  17. Pathway engineering to improve ethanol production by thermophilic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Lynd, L.R.

    1998-12-31

    Continuation of a research project jointly funded by the NSF and DOE is proposed. The primary project goal is to develop and characterize strains of C. thermocellum and C. thermosaccharolyticum having ethanol selectivity similar to more convenient ethanol-producing organisms. An additional goal is to document the maximum concentration of ethanol that can be produced by thermophiles. These goals build on results from the previous project, including development of most of the genetic tools required for pathway engineering in the target organisms. As well, we demonstrated that the tolerance of C. thermosaccharolyticum to added ethanol is sufficiently high to allow practical utilization should similar tolerance to produced ethanol be demonstrated, and that inhibition by neutralizing agents may explain the limited concentrations of ethanol produced in studies to date. Task 1 involves optimization of electrotransformation, using either modified conditions or alternative plasmids to improve upon the low but reproducible transformation, frequencies we have obtained thus far.

  18. Bioleaching of pollymetallic sulphide concentrate using thermophilic bacteria

    Directory of Open Access Journals (Sweden)

    Vuković Milovan

    2014-01-01

    Full Text Available An extreme thermophilic, iron-sulphur oxidising bacterial culture was isolated and adapted to tolerate high metal and solids concentrations at 70°C. Following isolation and adaptation, the culture was used in a batch bioleach test employing a 5-l glass standard magnetic agitated and aerated reactor, for the bioleaching of a copper-lead-zinc collective concentrate. The culture exhibited stable leach performance over the period of leach operation and overall copper and zinc extractions higher than 97%. Lead sulphide is transformed into lead sulphate remaining in the bioleach residue due to the low solubility in sulphate media. Brine leaching of bioleach residue yields 95% lead extraction. [Projekat Ministarstva nauke Republike Srbije, br. 34023

  19. The bioleaching of different sulfide concentrates using thermophilic bacteria

    Science.gov (United States)

    Torres, F.; Blázquez, M. L.; González, F.; Ballester, A.; Mier, J. L.

    1995-05-01

    The bioleaching of different mineral sulfide concentrates with thermophilic bacteria (genus Sulfolobus @#@) was studied. Since the use of this type of bacteria in leaching systems involves stirring and the control of temperature, the influence of the type of stirring and the pulp density on dissolution rates was studied in order to ascertain the optimum conditions for metal recovery. At low pulp densities, the dissolution kinetic was favored by pneumatic stirring, but for higher pulp densities, orbital stirring produced the best results. A comparative study of three differential concentrates, one mixed concentrate, and one global concentrate was made. Copper and iron extraction is directly influenced by bacterial activity, while zinc dissolution is basically due to an indirect mechanism that is activated in the presence of copper ions. Galvanic interactions between the different sulfides favors the selective bioleaching of some phases (sphalerite and chalcopyrite) and leads to high metal recovery rates. However, the formation of galvanic couples depends on the type of concentrate.

  20. Draft Genome Sequences of Four Thermophilic Spore Formers Isolated from a Dairy-Processing Environment

    Science.gov (United States)

    Caspers, Martien P. M.; Boekhorst, Jos; de Jong, Anne; Kort, Remco; Nierop Groot, Masja

    2016-01-01

    Spores of thermophilic spore-forming bacteria are a common cause of contamination in dairy products. Here, we report draft genome sequences of four thermophilic strains from a milk-processing plant or standard milk, namely, a Geobacillus thermoglucosidans isolate (TNO-09.023), Geobacillus stearothermophilus TNO-09.027, and two Anoxybacillus flavithermus isolates (TNO-09.014 and TNO-09.016). PMID:27516503

  1. Draft Genome Sequences of Four Thermophilic Spore Formers Isolated from a Dairy-Processing Environment.

    Science.gov (United States)

    Caspers, Martien P M; Boekhorst, Jos; de Jong, Anne; Kort, Remco; Nierop Groot, Masja; Abee, Tjakko

    2016-01-01

    Spores of thermophilic spore-forming bacteria are a common cause of contamination in dairy products. Here, we report draft genome sequences of four thermophilic strains from a milk-processing plant or standard milk, namely, a Geobacillus thermoglucosidans isolate (TNO-09.023), Geobacillus stearothermophilus TNO-09.027, and two Anoxybacillus flavithermus isolates (TNO-09.014 and TNO-09.016). PMID:27516503

  2. Cloning and sequencing of the gene encoding thermophilic beta-amylase of Clostridium thermosulfurogenes.

    OpenAIRE

    Kitamoto, N; Yamagata, H; Kato, T; Tsukagoshi, N; Udaka, S

    1988-01-01

    A gene coding for thermophilic beta-amylase of Clostridium thermosulfurogenes was cloned into Bacillus subtilis, and its nucleotide sequence was determined. The nucleotide sequence suggested that the thermophilic beta-amylase is translated from monocistronic mRNA as a secretory precursor with a signal peptide of 32 amino acid residues. The deduced amino acid sequence of the mature beta-amylase contained 519 residues with a molecular weight of 57,167. The amino acid sequence of the C. thermosu...

  3. [The thermophilic streptomycetes flora in milk powders and condensed milk products (author's transl)].

    Science.gov (United States)

    Falkowski, J

    1978-08-01

    247 specimens of powdered milk and 165 of condensed milk were tested for their contamination with thermophile Streptomycetes. Colonies of these contaminants were isolated from all specimens of powdered milk and from 73 samples of condensed sweeted milk. The isolated strains corresponded with the following species of thermophilic Streptomycetes: Thermoactinomyces vulgaris, Tsiklinsky 1899, Thermoactinomyces vulgaris, Tsiklinsky 1899 "giant colonies", Micromonospora sp. (Agre et al., 1).

  4. Aerobic methylcyclohexane-promoted epoxidation of stilbene over gold nanoparticles supported on Gd-doped titania

    KAUST Repository

    Mendez, Violaine

    2010-01-01

    Aerobic partial oxidations of alkanes and alkenes are important processes of the petrochemical industry. The radical mechanisms involved can be catalyzed by soluble salts of transition metals (Co, Cu, Mn...). We show here that the model methylcyclohexane/stilbene co-oxidation reaction can be efficiently catalyzed at lower temperature by supported gold nanoparticles. The support has little influence on gold intrinsic activity but more on the apparent reaction rates which are a combination of catalytic activity and diffusion limitations. These are here minimized by using gadolinium-doped titania nanocrystallites as support for gold nanoparticles. This material is obtained by mild hydrolysis of a new Gd4TiO(OiPr)14 bimetallic oxoalkoxide. It leads to enhanced wettability of the < 3 nm gold particles in the tert-butyl hydroperoxide (TBHP)-initiated epoxidation of stilbene in methylcyclohexane; Au/TiO2:Gd3+ is in turn as active as the state-of-the-art hydrophobic Au/SiO2 catalyst. The rate-determining step of this reaction is identified as the gold-catalyzed homolytic decomposition of TBHP generating radicals and initiating the methylcyclohexane-mediated epoxidation of stilbene, yielding a methylcyclohexan-1-ol/trans-stilbene oxide mixture. Methylcyclohexan-1-ol can also be obtained in the absence of the alkene in the gold-catalyzed solvent-free autoxidation of methylcyclohexane, evidencing the catalytic potential of gold nanoparticles for low temperature C-H activation. © 2010 The Royal Society of Chemistry.

  5. Presence and potential role of thermophilic bacteria in temperate terrestrial environments

    Science.gov (United States)

    Portillo, M. C.; Santana, M.; Gonzalez, J. M.

    2012-01-01

    Organic sulfur and nitrogen are major reservoirs of these elements in terrestrial systems, although their cycling remains to be fully understood. Both sulfur and nitrogen mineralization are directly related to microbial metabolism. Mesophiles and thermophiles were isolated from temperate environments. Thermophilic isolates were classified within the Firmicutes, belonging to the Geobacillus, Brevibacillus, and Ureibacillus genera, and showed optimum growth temperatures between 50°C and 60°C. Sulfate and ammonium produced were higher during growth of thermophiles both for isolated strains and natural bacterial assemblages. They were positively related to organic nutrient load. Temperature also affected the release of sulfate and ammonium by thermophiles. Quantitative, real-time reverse-transcription polymerase chain reaction on environmental samples indicated that the examined thermophilic Firmicutes represented up to 3.4% of the total bacterial community RNA. Temperature measurements during summer days showed values above 40°C for more than 10 h a day in soils from southern Spain. These results support a potential role of thermophilic bacteria in temperate terrestrial environments by mineralizing organic sulfur and nitrogen ruled by the existence and length of warm periods.

  6. Active Gold-Ceria and Gold-Ceria/titania Catalysts for CO Oxidation. From Single-Crystal Model Catalysts to Powder Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Jose A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Si, Rui [Brookhaven National Lab. (BNL), Upton, NY (United States); Evans, Jaime [Central Univ. of Venezuela, Caracas (Venezuela); Xu, Wenqian [Brookhaven National Lab. (BNL), Upton, NY (United States); Hanson, Jonathan C. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tao, Jing [Brookhaven National Lab. (BNL), Upton, NY (United States); Zhu, Yimei [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2014-07-23

    We studied CO oxidation on model and powder catalysts of Au-CeO2 and Au-CeOx/TiO2. Phenomena observed in Au-CeO2(1 1 1) and Au-CeO2/TiO2(1 1 0) provided useful concepts for designing and preparing highly active and stable Au-CeOx/TiO2 powder catalysts for CO oxidation. Small particles of Au dispersed on CeO2(1 1 1) displayed high catalytic activity, making Au-CeO2(1 1 1) a better CO oxidation catalyst than Au-TiO2(1 1 0) or Au-MgO(1 0 0). An excellent support for gold was found after depositing nanoparticles of ceria on TiO2(1 1 0). The CeOx nanoparticles act as nucleation centers for gold, improving dispersion of the supported metal and helping in the creation of reaction sites efficient for the adsorption of CO and the dissociation of the O2 molecule. High-surface area catalysts were prepared by depositing gold on ceria nanorods and CeOx/TiO2 powders. The samples were tested for the low-temperature (10–70 °C) oxygen-rich (1%CO/4%O2/He) CO oxidation reaction after pre-oxidation (20%O2/He, 300 °C) and pre-reduction (5%H2/He, 300 °C) treatments. Moreover, synchrotron-based operando X-ray diffraction (XRD) and X-ray absorption (XAS) spectroscopy were used to study the Au-CeO2 and Au-CeOx/TiO2 catalysts under reaction conditions. Our operando findings indicate that the most active phase of these catalysts for low-temperature CO oxidation consist of small particles of metallic Au dispersed on CeO2 or CeOx/TiO2.

  7. Start-up and HRT Influence in Thermophilic and Mesophilic Anaerobic Digesters Seeded with Waste Activated Sludge

    OpenAIRE

    Benabdallah, El-Hadj T.; Dosta, J.; Mata-Alvarez, J.

    2007-01-01

    Since thermophilic anaerobic digestion represents an efficient alternative to mesophilic anaerobic digestion, multiple studies have been developed to compare their performance and viability. One of the problems related to thermophilic anaerobic digestion is the availability of an adequate seed to start-up the process. The goal of this study is to evaluate the possibility of using waste activated sludge (WAS) as a seed for both mesophilic (35 °C) and thermophilic (55 °C) anaerobic digesters...

  8. Conjugative plasmid transfer from Escherichia coli is a versatile approach for genetic transformation of thermophilic Bacillus and Geobacillus species.

    Science.gov (United States)

    Tominaga, Yurie; Ohshiro, Takashi; Suzuki, Hirokazu

    2016-05-01

    We previously demonstrated efficient transformation of the thermophile Geobacillus kaustophilus HTA426 using conjugative plasmid transfer from Escherichia coli BR408. To evaluate the versatility of this approach to thermophile transformation, this study examined genetic transformation of various thermophilic Bacillus and Geobacillus spp. using conjugative plasmid transfer from E. coli strains. E. coli BR408 successfully transferred the E. coli-Geobacillus shuttle plasmid pUCG18T to 16 of 18 thermophiles with transformation efficiencies between 4.1 × 10(-7) and 3.8 × 10(-2)/recipient. Other E. coli strains that are different from E. coli BR408 in intracellular DNA methylation also generated transformants from 9 to 15 of the 18 thermophiles, including one that E. coli BR408 could not transform, although the transformation efficiencies of these strains were generally lower than those of E. coli BR408. The conjugation was performed by simple incubation of an E. coli donor and a thermophile recipient without optimization of experimental conditions. Moreover, thermophile transformants were distinguished from abundant E. coli donor only by high temperature incubation. These observations suggest that conjugative plasmid transfer, particularly using E. coli BR408, is a facile and versatile approach for plasmid introduction into thermophilic Bacillus and Geobacillus spp., and potentially a variety of other thermophiles.

  9. [Anaerobic-aerobic infection in acute appendicitis].

    Science.gov (United States)

    Mamchich, V I; Ulitovskiĭ, I V; Savich, E I; Znamenskiĭ, V A; Beliaeva, O A

    1998-01-01

    362 patients with acute appendicitis (AA) were examined. For microbiological diagnosis of aerobic and anaerobic nonclostridial microflora we used complex accelerated methods (including evaluation of gram-negative microorganisms in comparison with tinctorial-fermentative method of differential staining according to oxygen sensitivity of catalasopositive together with aerobic and cathalasonegative anaerobic microorganisms) as well as complete bacteriologic examination with determination of sensitivity of the above microorganism to antimicrobial remedies. High rate of aerobic-anaerobic microbial associations and substantial identity of microflora from appendicis and exudate from abdominal cavity was revealed, which evidenced the leading role of endogenous microorganisms in etiology and pathogenesis of AA and peritonitis i. e. autoinfection. In patients with destructive forms of AA, complicated by peritonitis it is recommended to use the accelerated method of examination of pathologic material as well as the complete scheme of examination with the identification of the isolated microorganisms and the correction of antibiotic treatment. PMID:9511291

  10. Drying and recovery of aerobic granules.

    Science.gov (United States)

    Hu, Jianjun; Zhang, Quanguo; Chen, Yu-You; Lee, Duu-Jong

    2016-10-01

    To dehydrate aerobic granules to bone-dry form was proposed as a promising option for long-term storage of aerobic granules. This study cultivated aerobic granules with high proteins/polysaccharide ratio and then dried these granules using seven protocols: drying at 37°C, 60°C, 4°C, under sunlight, in dark, in a flowing air stream or in concentrated acetone solutions. All dried granules experienced volume shrinkage of over 80% without major structural breakdown. After three recovery batches, although with loss of part of the volatile suspended solids, all dried granules were restored most of their original size and organic matter degradation capabilities. The strains that can survive over the drying and storage periods were also identified. Once the granules were dried, they can be stored over long period of time, with minimal impact yielded by the applied drying protocols. PMID:27392096

  11. Mechanism of Kenaf Retting Using Aerobes

    Institute of Scientific and Technical Information of China (English)

    卢士森; 陈季华; 黄秀宝

    2001-01-01

    The experimental results showed that the duration of microbial retting processing of kenaf fibers by using aerobic microbe was four times shorter than that by using anaerobic microbe. The residual gum percentage,breaking strength, breaking elongation and linear density of aerobic retted kenaf bundle fibers did not show significantly difference with that of anaerobic retted kenaf bundle fibers by ANOVA-Tukey's studentized test at a = 5% except for the softness. The bioenergetic principle and the calculation of the amount of ATP produced during the decomposition processing of kenaf gums were used to explain why the retting duration in the case of using aerobic microbes was much shorter than that of using anaerobic microbes.

  12. Phytotoxicity Evolution of Biowastes Undergoing Aerobic Decomposition

    Directory of Open Access Journals (Sweden)

    M. R. Soares

    2013-01-01

    Full Text Available This study is mainly focused on the phytotoxicity improvement within five to six weeks of thermophilic composting of biowastes. Two sets of experiments were conducted involving both sawdust and rice husk as bulking agents, which were composted in self-heating reactors with potato-peel industrial waste and grass clippings as organic materials. The main variables observed over time were temperature, oxygen uptake rate (OUR, biodegradability, and germination index (GI. The effects of compost water extracts on seed germination and primary root growth of garden cress (Lepidium sativum were measured to calculate the germination index (GI. The biodegradability was well assessed by measuring lignin content, using the Klason method. The experimental results showed that initial compositions strongly determined the profiles of phytotoxicity and the period of maturation. The phytotoxicity assessment in the experiments with sawdust revealed that after 39 days of composting, the GI attained the maximum value of 30%, but using rice husk, it was possible to reach 70% in the same period of time. Our findings showed that, at a certain point, higher cumulative OUR led to lower germination index, and proportional relationship between the cumulative OUR and GI was observed, after thermophilic phase.

  13. A culture-dependent survey of thermophilic bacteria from hot springs in Xiamen area in China

    Institute of Scientific and Technical Information of China (English)

    YANG Bo; OUYANG Jianping; AO Jingqun; CHEN Xinhua

    2009-01-01

    Microbes are believed to play important roles in ecosystem function in many environments. The hot springs of Xiamen Island are close to the Xiamen Sea, and may have some characteristics different from those of inland hot springs. Microbes living in the hot springs of Xiamen may have new characteristics. However, little is known about microbial communities of hot springs close to the Xiamen Sea. A cuhure-dependent survey of microbial population in the Xiamen hot springs was pcrformed by using an approach combining total cellular protein profile identification and 16S rRNA gene sequencing. A total of 328 isolates of bacteria were obtained from liquid and sediment samples from the Xiamen hot springs, including neutrophilie thermophilic bacteria and moderately thermophilic acidophiles. Neutrophilic thermophilic bacteria, which grow at a temperature range of 55-90℃ including Rhodothermus marinus (Strain 1) , Thermus thermophilus (Strain 2), Thermus thiopara (Strain 3) , Geobacillus stearothermophilus(Strain 4) , Geobacillus thermoleovorans (Strain 5) , and Pseudomonas pseudoal-caligenes (Strain 6), were recovered by 2216E plates. Moderately thermophilic acidophiles, which can grow at temperatures above 50℃ and a pH range of 1. 8-3.5 such as Alicyclobacillus acidoterrestris (Strain 8) , Sul-fobacillus acidophilus (Strain 9), and Sulfobacillus thermosulfidooxidans (Strain 10), were isolated on selective solid medium containing sulfur and Fe2+. Among these strains, Rhodothermus marinus, Thermus thermophilus and Geobacillus stearothermophilus are not only thermophilcs, but also halophiles. One bacterium strain (Strain 6) shared 99% nucleotide sequence homology with Pseudomonas pseudoalcaligenes on the 16S rRNA gene se-quence, but was quite different from Pseudomonas pseudoalcaligenes in biological characteristics, suggesting that it may represent a novel thermophilic species. Results indicated that various species of neutrophilic thermophiles and moderately thermophilic

  14. ANAEROBIC AND AEROBIC TREATMENT OF CHLORINATED ALIPHATIC COMPOUNDS

    Science.gov (United States)

    Biological degradation of 12 chlorinated aliphatic compounds (CACs) was assessed in bench-top reactors and in serum bottle tests. Three continuously mixed daily batch-fed reactor systems were evaluated: anaerobic, aerobic, and sequential-anaerobic-aerobic (sequential). Glucose,...

  15. Alicyclobacillus dauci sp. nov., a slightly thermophilic, acidophilic bacterium isolated from a spoiled mixed vegetable and fruit juice product.

    Science.gov (United States)

    Nakano, Chisa; Takahashi, Naoto; Tanaka, Naoto; Okada, Sanae

    2015-02-01

    A novel, moderately thermophilic, acidophilic, Gram-variable, rod-shaped, endospore-forming bacterium was isolated from a spoiled mixed vegetable and fruit juice product that had the off-flavour of guaiacol. The bacterium, strain 4F(T), grew aerobically at 20-50 °C (optimum 40 °C) and pH 3.0-6.0 (optimum pH 4.0) and produced acid from glycerol, d-galactose and d-glucose. It contained menaquinone-7 (MK-7) as the major isoprenoid quinone and the DNA G+C content was 49.6 mol%. The predominant cellular fatty acids of strain 4F(T) were ω-alicyclic (ω-cyclohexane fatty acids), which are characteristic of the genus Alicyclobacillus. Phylogenetic analyses based on 16S rRNA gene sequences showed that the strain belongs to the Alicyclobacillus cluster, and is related most closely to the type strains of Alicyclobacillus acidoterrestris (97.4 % similarity) and Alicyclobacillus fastidiosus (97.3 %). Strain 4F(T) produced guaiacol from vanillic acid. It can be distinguished from related species by its acid production type and guaiacol production. On the basis of phenotypic characteristics, phylogenetic analysis and DNA-DNA relatedness values, it can be concluded that the strain represents a novel species of the genus Alicyclobacillus, for which the name Alicyclobacillus dauci sp. nov. is proposed; the type strain is 4F(T) ( = DSM 28700(T) = NBRC 108949(T) = NRIC 0938(T)). PMID:25505343

  16. Purification and partial characterization of bacillocin 490, a novel bacteriocin produced by a thermophilic strain of Bacillus licheniformis

    Directory of Open Access Journals (Sweden)

    De Felice Maurilio

    2002-04-01

    Full Text Available Abstract Background Applications of bacteriocins as food preservatives have been so far limited, principally because of their low antimicrobial activity in foods. Nisin is the only bacteriocin of significant use, but applications are restricted principally because of its very low activity at neutral or alkaline pH. Thus the isolation of new bacteriocins active in foods is desirable. Results We isolated a Bacillus licheniformis thermophilic strain producing a bacteriocin with some novel features, named here bacillocin 490. This bacteriocin was inactivated by pronase E and proteinase K and was active against closely related Bacillus spp. both in aerobic and in anaerobic conditions. Bactericidal activity was kept during storage at 4°C and was remarkably stable in a wide pH range. The bacteriocin was partially purified by elution after adhesion to cells of the food-isolated strain Bacillus smithii and had a rather low mass (2 KDa. Antimicrobial activity against B. smithii was observed also when this organism was grown in water buffalo milk. Conclusions Bacillocin 490 is a novel candidate as a food anti-microbial agent since it displays its activity in milk, is stable to heat treatment and during storage, is active in a wide pH range and has bactericidal activity also at high temperature. These features may allow the use of bacillocin 490 during processes performed at high temperature and as a complementary antimicrobial agent of nisin against some Bacillus spp. in non-acidic foods. The small size suggests its use on solid foods.

  17. Reduction of hexavalent chromium by the thermophilic methanogen Methanothermobacter thermautotrophicus

    Science.gov (United States)

    Singh, Rajesh; Dong, Hailiang; Liu, Deng; Zhao, Linduo; Marts, Amy R.; Farquhar, Erik; Tierney, David L.; Almquist, Catherine B.; Briggs, Brandon R.

    2015-01-01

    Despite significant progress on iron reduction by thermophilic microorganisms, studies on their ability to reduce toxic metals are still limited, despite their common co-existence in high temperature environments (up to 70 °C). In this study, Methanothermobacter thermautotrophicus, an obligate thermophilic methanogen, was used to reduce hexavalent chromium. Experiments were conducted in a growth medium with H2/CO2 as substrate with various Cr6+ concentrations (0.2, 0.4, 1, 3, and 5 mM) in the form of potassium dichromate (K2Cr2O7). Time-course measurements of aqueous Cr6+ concentrations using 1,5-diphenylcarbazide colorimetric method showed complete reduction of the 0.2 and 0.4 mM Cr6+ solutions by this methanogen. However, much lower reduction extents of 43.6%, 13.0%, and 3.7% were observed at higher Cr6+ concentrations of 1, 3 and 5 mM, respectively. These lower extents of bioreduction suggest a toxic effect of aqueous Cr6+ to cells at this concentration range. At these higher Cr6+ concentrations, methanogenesis was inhibited and cell growth was impaired as evidenced by decreased total cellular protein production and live/dead cell ratio. Likewise, Cr6+ bioreduction rates decreased with increased initial concentrations of Cr6+ from 13.3 to 1.9 μM h-1. X-ray absorption near-edge structure (XANES) spectroscopy revealed a progressive reduction of soluble Cr6+ to insoluble Cr3+ precipitates, which was confirmed as amorphous chromium hydroxide by selected area electron diffraction pattern. However, a small fraction of reduced Cr occurred as aqueous Cr3+. Scanning and transmission electron microscope observations of M. thermautotrophicus cells after Cr6+ exposure suggest both extra- and intracellular chromium reduction mechanisms. Results of this study demonstrate the ability of M. thermautotrophicus cells to reduce toxic Cr6+ to less toxic Cr3+ and its potential application in metal bioremediation, especially at high temperature subsurface radioactive waste disposal

  18. Biological hydrogen production from biomass by thermophilic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Claassen, P.A.M.; Mars, A.E.; Budde, M.A.W.; Lai, M.; de Vrije, T. [Wageningen UR, Agrotechnology and Food Sciences Group (AFSG), Business Unit Biobased Products, P.O. Box 17, 6700 AA Wageningen, (Netherlands); van Niel, E.W.J. [Lund University, Applied microbiology, P.O. Box 124, 221 000 Lund, (Sweden)

    2006-07-01

    To meet the reduction of the emission of CO{sub 2} imposed by the Kyoto protocol, hydrogen should be produced from renewable primary energy. Besides the indirect production of hydrogen by electrolysis using electricity from renewable resources, such as sunlight, wind and hydropower, hydrogen can be directly produced from biomass. At present, there are two strategies for the production of hydrogen from biomass: the thermochemical technology, such as gasification, and the biotechnological approach using micro-organisms. Biological hydrogen production delivers clean hydrogen with an environmental-friendly technology and is very suitable for the conversion of wet biomass in small-scale applications, thus having a high chance of becoming an economically feasible technology. Many micro-organisms are able to produce hydrogen from mono- and disaccharides, starch and (hemi)cellulose under anaerobic conditions. The anaerobic production of hydrogen is a common phenomenon, occurring during the process of anaerobic digestion. Here, hydrogen producing micro-organisms are in syn-trophy with methanogenic bacteria which consume the hydrogen as soon as it is produced. In this way, hydrogen production remains obscure and methane is the end-product. By uncoupling hydrogen production from methane production, hydrogen becomes available for recovery and exploitation. This study describes the use of extreme thermophilic bacteria, selected because of a higher hydrogen production efficiency as compared to mesophilic bacteria, for the production of hydrogen from renewable resources. As feedstock energy crops like Miscanthus and Sorghum bicolor and waste streams like domestic organic waste, paper sludge and potato steam peels were used. The feedstock was pretreated and/or enzymatically hydrolyzed prior to fermentation to make a fermentable substrate. Hydrogen production by Caldicellulosiruptor saccharolyticus, Thermotoga elfii and T. neapolitana on all substrates was observed. Nutrient

  19. Biological hydrogen production from biomass by thermophilic bacteria

    International Nuclear Information System (INIS)

    To meet the reduction of the emission of CO2 imposed by the Kyoto protocol, hydrogen should be produced from renewable primary energy. Besides the indirect production of hydrogen by electrolysis using electricity from renewable resources, such as sunlight, wind and hydropower, hydrogen can be directly produced from biomass. At present, there are two strategies for the production of hydrogen from biomass: the thermochemical technology, such as gasification, and the biotechnological approach using micro-organisms. Biological hydrogen production delivers clean hydrogen with an environmental-friendly technology and is very suitable for the conversion of wet biomass in small-scale applications, thus having a high chance of becoming an economically feasible technology. Many micro-organisms are able to produce hydrogen from mono- and disaccharides, starch and (hemi)cellulose under anaerobic conditions. The anaerobic production of hydrogen is a common phenomenon, occurring during the process of anaerobic digestion. Here, hydrogen producing micro-organisms are in syn-trophy with methanogenic bacteria which consume the hydrogen as soon as it is produced. In this way, hydrogen production remains obscure and methane is the end-product. By uncoupling hydrogen production from methane production, hydrogen becomes available for recovery and exploitation. This study describes the use of extreme thermophilic bacteria, selected because of a higher hydrogen production efficiency as compared to mesophilic bacteria, for the production of hydrogen from renewable resources. As feedstock energy crops like Miscanthus and Sorghum bicolor and waste streams like domestic organic waste, paper sludge and potato steam peels were used. The feedstock was pretreated and/or enzymatically hydrolyzed prior to fermentation to make a fermentable substrate. Hydrogen production by Caldicellulosiruptor saccharolyticus, Thermotoga elfii and T. neapolitana on all substrates was observed. Nutrient requirements

  20. Pyrinomonas methylaliphatogenes gen. nov., sp. nov., a novel group 4 thermophilic member of the phylum Acidobacteria from geothermal soils.

    Science.gov (United States)

    Crowe, M A; Power, J F; Morgan, X C; Dunfield, P F; Lagutin, K; Rijpstra, W I C; Rijpstra, I C; Vyssotski, G N S; Sinninghe Damste, J S; Houghton, K M; Ryan, J L J; Stott, M B

    2014-01-01

    An aerobic, thermophilic, moderately acidophilic non-spore-forming bacterium, strain K22(T), was isolated from geothermally heated soil at Mount Ngauruhoe, New Zealand. On the basis of 16S rRNA gene sequence similarity, K22(T) was shown to belong to subdivision 4 of the phylum Acidobacteria and to be most closely related to 'Candidatus Chloracidobacterium thermophilum' (86 %) and Blastocatella fastidiosa (86 %). Cells stained Gram-negative and were catalase and oxidase-positive. The major fatty acids detected were iso-C15 : 0, iso-C17 : 0, iso-C19 : 0 and iso-C21 : 0 when standard lipid extraction protocols were employed. Analysis of the total cell lipid acid hydrolysate also detected membrane-spanning and ether lipids, which made up approximately 40 % of the total membrane composition. These lipids included dicarboxylic (iso-diabolic) acid and the glyceryl ether of alkyl analogues of iso-C15 : 0 and iso-diabolic acid. The G+C content of the genomic DNA was 59.6 mol% and the primary respiratory quinone was MK-8. Strain K22(T) grew at 50-69 °C with an optimum temperature of 65 °C and at pH 4.1-7.8 with an optimum growth pH of 6.5. NaCl tolerance was up to 1 % (w/v). Cells displayed a chemoheterotrophic and obligately aerobic metabolism. Cells grew on nutrient broth, alginate, arabinose, Casamino acids, glucose, lactate, formate, mannose, sodium alginate, peptone, sucrose, tryptone, xanthan, xylan, xylose and yeast extract. Nitrogen sources included nitrate, ammonium, urea, yeast extract and Casamino acids, but not dinitrogen gas. The distinct phylogenetic position and the phenotypic characteristics separate strain K22(T) from all other members of the class Acidobacteria and indicate that it represents a novel species and genus, for which the name Pyrinomonas methylaliphatogenes gen. nov., sp. nov. is proposed. The type strain of the type species is K22(T) ( = DSM 25857(T) = ICMP 18710(T)). PMID:24048862

  1. THE RATE AND NATURE OF WOMEN INJURIES IN STEP AEROBICS

    OpenAIRE

    Gholam Ali Ghasemi; Vahid Zolaktaf; Fereshteh Kazemi

    2011-01-01

    Step aerobics is a form of aerobic exercise that utilizes a 90×45×20 centimeter platform. ItsInternational competitions are held annually. This sport is popular in Iranian specialist femalesport clubs and its national competitions are growing gradually. The purpose of this survey wasto determine the rate and nature of sport injury in Iranian athletes of step aerobics. Weadministered a structured interview using a modified version of standard questionnaire of"Aerobics Pathology". The populatio...

  2. Reflections on Psychotherapy and Aerobic Exercise.

    Science.gov (United States)

    Silverman, Wade

    This document provides a series of reflections by a practicing psychologist on the uses of aerobic workouts in psychotherapy. Two case histories are cited to illustrate the contention that the mode of exercise, rather than simply its presence or absence, is the significant indicator of a patient's emotional well-being or psychopathology. The first…

  3. Glycogen metabolism in aerobic mixed cultures

    DEFF Research Database (Denmark)

    Dircks, Klaus; Beun, J.J.; van Loosdrecht, M.C.M.;

    2001-01-01

    In this study, the metabolism of glycogen storage and consumption in mixed cultures under aerobic conditions is described. The experimental results are used to calibrate a metabolic model, which as sole stoichiometric variables has the efficiency of oxidative phosphorylation (delta) and maintenan...

  4. Coating SiO2 Support with TiO2 or ZrO2 and Effects on Structure and CO Oxidation Performance of Pt Catalysts

    Directory of Open Access Journals (Sweden)

    Mi-Young Kim

    2013-02-01

    Full Text Available In this work, we studied how TiO2 and ZrO2 coatings enhance the CO oxidation performance of SiO2-supported Pt catalysts under conditions relevant to automotive emissions control. SiO2 was coated with metal oxides TiO2 or ZrO2 by sol-gel method and the subsequent Pt loading was done by incipient wetness method. The prepared catalysts Pt/TiO2-SiO2 and Pt/ZrO2-SiO2 were compared with Pt/SiO2 and Pt/Al2O3 in fresh, sulfated, and hydrothermally aged states. The structure of the catalysts was characterized with BET, XRD, TEM, EDS, EXAFS, XANES, TPD and TPR to help interpret the CO oxidation performance. Higher dispersion, stability, and oxidation state of Pt were achieved on TiO2-SiO2 and ZrO2-SiO2 supports due to stronger metal-support interaction leading to superior CO oxidation performance compared to Pt/SiO2 and Pt/Al2O3. TiO2 and ZrO2 coatings introduced surface acidity but negligible basicity, which is a likely reason for the weak and low adsorption of SO2. The results suggest that the sol-gel coating of SiO2 with metal oxides could be an attractive strategy for designing automotive oxidation catalysts with enhanced performance such as low-temperature activity, sulfur tolerance, and hydrothermal stability.

  5. Atmospheric-Pressure DBD Cold Plasma for Preparation of High Active Au/P25 Catalysts for Low-Temperature CO Oxidation

    Science.gov (United States)

    Di, Lanbo; Zhan, Zhibin; Zhang, Xiuling; Qi, Bin; Xu, Weijie

    2016-05-01

    Cold plasma generated by dielectric barrier discharge (DBD) at atmospheric pressure was adopted for preparation of commercial TiO2 Degussa P25 supported Au catalysts (Au/P25-P) with the assistance of the deposition-precipitation procedure. The influences of the plasma reduction time and calcination on the performance of the Au/P25-P catalysts were investigated. CO oxidation was performed to investigate the catalytic activity of the Au/P25 catalysts. The results show that DBD cold plasma for the fabrication of Au/P25-P catalysts is a fast process, and Au/P25-P (4 min) exhibited the highest CO oxidation activity due to the complete reduction of Au compounds and less consumption of oxygen vacancies. In order to form more oxygen vacancies active species, Au/P25-P was calcined to obtain Au/P25-PC catalysts. Interestingly, Au/P25-PC exhibited the highest activity for CO oxidation among the Au/P25 samples. The results of transmission electron microscopy (TEM) indicated that the smaller size and high distribution of Au nanoparticles are the mean reasons for a high performance of Au/P25-PC. Atmospheric-pressure DBD cold plasma was proved to be of great efficiency in preparing high performance supported Au catalysts. supported by National Natural Science Foundation of China (Nos. 11505019, 21173028), the Science and Technology Research Project of Liaoning Provincial Education Department (No. L2013464), the Scientific Research Foundation for the Doctor of Liaoning Province (No. 20131004), and the Dalian Jinzhou New District Science and Technology Plan Project (No. KJCX-ZTPY-2014-0001)

  6. Effect of Preparation Methods on Al2O3 Supported CuO-CeO2-ZrO2 Catalysts for CO Oxidation

    Directory of Open Access Journals (Sweden)

    Gaurav Rattan

    2012-12-01

    Full Text Available To examine the effect of preparation methods, four catalyst samples having same composition (CuCe5.17Zr3.83Ox/g-Al2O3 (15wt% were prepared by four different methods for CO oxidation. The catalysts were prepared by co-impregnation, citric acid sol-gel, urea nitrate combustion and urea gelation co-precipitation methods, and characterized by BET, XRD, TGA/DSC and SEM. The The air oxidation of CO was carried out in a tubular fixed bed reactor under the following operating conditions: catalyst weight - 100 mg, temperature - ambient to 250 oC, pressure - atmospheric, 2.5% CO in air, total feed rate - 60 ml/min.  It was observed that the catalytic activity greatly influenced by the preparation methods. The highest activity of the catalyst prepared by the sol gel method appeared to be associated with its largest BET surface area. All the four catalysts were active for CO oxidation and did not show deactivation of catalytic activity for 50 hours of continuous runs. The ranking order of the preparation methods of the catalyst is as follows: sol-gel > co-impregnation > urea gelation > urea nitrate combustion. Copyright © 2012 by BCREC UNDIP. All rights reservedReceived: 14th June 2012, Revised: 8th September 2012, Accepted: 19th September 2012[How to Cite: G. Rattan, R. Prasad, R.C.Katyal. (2012. Effect of Preparation Methods on Al2O3 Supported CuO-CeO2-ZrO2 Catalysts for CO Oxidation. Bulletin of Chemical Reaction Engineering & Catalysis, 7(2: 112-123. doi:10.9767/bcrec.7.2.3646.112-123] [How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.2.3646.112-123 ] | View in 

  7. Effect of different redox mediators during thermophilic azo dye reduction by anaerobic granular sludge and comparative study between mesophilic (30C) and thermophilic (55C) treatments for decolourisation of textile wastewaters

    NARCIS (Netherlands)

    Bezerra Dos Santos, A.; Bisschops, I.A.E.; Cervantes, F.J.; Lier, van J.B.

    2004-01-01

    The impact of different redox mediators on colour removal of azo dye model compounds and textile wastewater by thermophilic anaerobic granular sludge (55 C) was investigated in batch assays. Additionally, a comparative study between mesophilic (30 C) and thermophilic (55 C) colour removal was perfor

  8. EFFECTS OF AQUA AEROBICS AND FLOOR AEROBICS ON BREATH HOLDING TIME AMONG SCHOOL GIRLS

    OpenAIRE

    P.V. Shelvam; S. Arunadevi

    2013-01-01

    The purpose of the study was to find out the effects of aqua aerobics and floor aerobics on breath holding time among school girls. To achieve this purpose of the study, ninety school girls were selected as subjects who were studied Cornation Higher Secondary School, Sivakasi. The selected subjects were aged between 15 to 17 years. The selected subjects were randomly divided into three groups of 30 subjects each group. Group one acted as experimental group I and group two acted as experimenta...

  9. Use of periodic variations of reactant concentrations in time resolved ftir studies of CO oxidation on Pd/ZrO{sub 2} catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ortelli, E.; Wokaun, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    Sine wave modulation of feed concentrations was used to induce dynamic variations in the concentrations of products, intermediates and reactants, which were monitored in a diffuse reflectance FTIR (DRIFT) cell. The phase shift {Delta}{phi} between the external perturbation of the feed and the signals of products, intermediates and reactants was examined in dependence on the modulation frequency {omega}. Reaction constants of a simplified model mechanism were estimated for a Pd{sub 25}Zr{sub 75} based catalyst for CO oxidation. (author) 1 fig., 2 refs.

  10. Catalytic performance and structural characterization of ferric oxide and its composite oxides supported gold catalysts for low-temperature CO oxidation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The preparation and catalytic activity of ferric oxide and its composite oxides supported gold catalysts for Iow-temperature CO oxidation were investigated detailedly, and characterized extensively by XRD, XPS, TPR, EC and XAFS techniques. It was found that containing highly dis persed Au of partially oxidized state, these nano-structured oxides supported Au/Fe2O3 and Au/NiFe2O4 catalysts had higher Iow-temperature activities. The possible catalytic active center is the gold of partially oxidized state (Auζ+).

  11. In Situ X-ray Absorption Analysis of ~1.8 nm Dendrimer-Encapsulated Platinum Nanoparticles During Electrochemical CO Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Weir, M.; Myers, V; Frenkel, A; Crooks, R

    2010-01-01

    We report an in situ X-ray absorption-fine structure (XAFS) spectroscopic analysis of {approx}1.8 nm Pt dendrimer-encapsulated nanoparticles (DENs) during electrocatalytic oxidation of CO. The results indicate that Pt nanoparticles encapsulated within poly(amidoamine) (PAMAM) dendrimers and immobilized on a carbon electrode retain their electrocatalytic activity and are structurally stable for extended periods during CO oxidation. This is a significant finding, because nanoparticles in this size range are good experimental models for comparison to first-principles calculations if they remain stable.

  12. A Single-Site Platinum CO Oxidation Catalyst in Zeolite KLTL: Microscopic and Spectroscopic Determination of the Locations of the Platinum Atoms

    Energy Technology Data Exchange (ETDEWEB)

    Kistler, Joseph D.; Chotigkrai, Nutchapon; Xu, Pinghong; Enderle, Bryan; Praserthdam, Piyasan; Chen, Cong-Yan; Browning, Nigel D.; Gates, Bruce C.

    2014-07-01

    A stable site-isolated mononuclear platinum catalyst with a well-defined structure is presented. Platinum complexes supported in zeolite KLTL were synthesized from [Pt(NH3)4](NO3)2, oxidized at 633 K, and used to catalyze CO oxidation. Finally, IR and X-ray absorption spectra and electron micrographs determine the structures and locations of the platinum complexes in the zeolite pores, demonstrate the platinum-support bonding, and show that the platinum remained site isolated after oxidation and catalysis.

  13. Enzymatic Screening and Molecular Characterization of Thermophilic Bacterial Strains Isolated from Hotspring of Tatopani, Bhurung, Nepal

    Directory of Open Access Journals (Sweden)

    Hriush Adhikari

    2015-09-01

    Full Text Available Background and Aim: In Nepal not much of study of Thermophilic area and Thermophiles have been done. Thermophilic bacteria are less studied but are important group of microorganisms due to their ability to produce industrially important enzymes. Methods: In this study, thermophilic bacteria were isolated from hot spring of Bhurung, Nepal. Wide range of bacteria that could grow at high temperatures and tolerate extreme temperature were characterized by morphology, biochemistry and sequencing of its 16S rRNA gene sequence. The isolates were screened for production of extracellular enzymes like protease, amylase, lipase, cellulase, caseinase, pectinase and xylanase activity. Phylogenetic tree construction and G+C content evaluation of the isolate was also studied. Results: 15 isolates with ability to tolerate high temperatures were identified as Bacillus sp. by morphology, biochemistry and sequencing of its 16S rRNA gene sequence. BLAST search analysis of the sequence was performed and result showed maximum identity (99% similarity with Bacillus licheniformis, Bacillus subtilis and Bacillus pumilus. Isolated strains exhibited considerable amount of extracellular exozymes activity. Phylogenetic analysis of the isolates revealed the relatedness among the species. The G+C content of each species was also evaluated and was found to be in range of 54.87 to 55.54%. Conclusion: The study of isolates confirmed that the isolated Bacillus sp. to be a true thermophile and could be a source of various thermostable exozymes which can be exploited for pharmaceutical and industrials applications. Much detailed study of the isolates can

  14. Effect of salinity and acidity on bioleaching activity of mesophilic and extremely thermophilic bacteria

    Institute of Scientific and Technical Information of China (English)

    H.DEVECI; M.A.JORDAN; N.POWELL; I.ALP

    2008-01-01

    The effects of bacterial strain,salinity and pH on the bioleaching of a complex ore using mesophilic and extremely thermophilic bacteria were investigated and the statistical analysis of the results was performed using ERGUN's test.The extreme thermophiles were shown to display superior kinetics of dissolution of zinc compared with the mesophiles as confirmed by the statistical analysis.Bioleaching performance of the extreme thermophiles is found to improve in response to the increase in acidity (pH from 2.0 to 1.0) whilst the activity of the mesophiles is adversely affected by decreasing pH.Statistical analysis of the bioleaching data indicates that the effect of pH is insignificant in the range of pH 1.0-1.2 for the extreme thermophiles and pH 1.4-2.0 for the mesophiles.Salinity is shown to have a suppressing effect on the mesophiles.However,the extreme thermophiles appear to be halophilic in character as they could operate efficiently under saline conditions (1%-4%C1- (w/v)).

  15. Community dynamics and glycoside hydrolase activities of thermophilic bacterial consortia adapted to switchgrass

    Energy Technology Data Exchange (ETDEWEB)

    Gladden, J.M.; Allgaier, M.; Miller, C.S.; Hazen, T.C.; VanderGheynst, J.S.; Hugenholtz, P.; Simmons, B.A.; Singer, S.W.

    2011-05-01

    Industrial-scale biofuel production requires robust enzymatic cocktails to produce fermentable sugars from lignocellulosic biomass. Thermophilic bacterial consortia are a potential source of cellulases and hemicellulases adapted to harsher reaction conditions than commercial fungal enzymes. Compost-derived microbial consortia were adapted to switchgrass at 60 C to develop thermophilic biomass-degrading consortia for detailed studies. Microbial community analysis using small-subunit rRNA gene amplicon pyrosequencing and short-read metagenomic sequencing demonstrated that thermophilic adaptation to switchgrass resulted in low-diversity bacterial consortia with a high abundance of bacteria related to thermophilic paenibacilli, Rhodothermus marinus, and Thermus thermophilus. At lower abundance, thermophilic Chloroflexi and an uncultivated lineage of the Gemmatimonadetes phylum were observed. Supernatants isolated from these consortia had high levels of xylanase and endoglucanase activities. Compared to commercial enzyme preparations, the endoglucanase enzymes had a higher thermotolerance and were more stable in the presence of 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]), an ionic liquid used for biomass pretreatment. The supernatants were used to saccharify [C2mim][OAc]-pretreated switchgrass at elevated temperatures (up to 80 C), demonstrating that these consortia are an excellent source of enzymes for the development of enzymatic cocktails tailored to more extreme reaction conditions.

  16. Isobutanol production at elevated temperatures in thermophilic Geobacillus thermoglucosidasius.

    Science.gov (United States)

    Lin, Paul P; Rabe, Kersten S; Takasumi, Jennifer L; Kadisch, Marvin; Arnold, Frances H; Liao, James C

    2014-07-01

    The potential advantages of biological production of chemicals or fuels from biomass at high temperatures include reduced enzyme loading for cellulose degradation, decreased chance of contamination, and lower product separation cost. In general, high temperature production of compounds that are not native to the thermophilic hosts is limited by enzyme stability and the lack of suitable expression systems. Further complications can arise when the pathway includes a volatile intermediate. Here we report the engineering of Geobacillus thermoglucosidasius to produce isobutanol at 50°C. We prospected various enzymes in the isobutanol synthesis pathway and characterized their thermostabilities. We also constructed an expression system based on the lactate dehydrogenase promoter from Geobacillus thermodenitrificans. With the best enzyme combination and the expression system, 3.3g/l of isobutanol was produced from glucose and 0.6g/l of isobutanol from cellobiose in G. thermoglucosidasius within 48h at 50°C. This is the first demonstration of isobutanol production in recombinant bacteria at an elevated temperature.

  17. Biogeography of thermophilic phototrophic bacteria belonging to Roseiflexus genus.

    Science.gov (United States)

    Gaisin, Vasil A; Grouzdev, Denis S; Namsaraev, Zorigto B; Sukhacheva, Marina V; Gorlenko, Vladimir M; Kuznetsov, Boris B

    2016-03-01

    Isolated environments such as hot springs are particularly interesting for studying the microbial biogeography. These environments create an 'island effect' leading to genetic divergence. We studied the phylogeographic pattern of thermophilic anoxygenic phototrophic bacteria, belonging to the Roseiflexus genus. The main characteristic of the observed pattern was geographic and geochronologic fidelity to the hot springs within Circum-Pacific and Alpine-Himalayan-Indonesian orogenic belts. Mantel test revealed a correlation between genetic divergence and geographic distance among the phylotypes. Cluster analysis revealed a regional differentiation of the global phylogenetic pattern. The phylogeographic pattern is in correlation with geochronologic events during the break up of Pangaea that led to the modern configuration of continents. To our knowledge this is the first geochronological scenario of intercontinental prokaryotic taxon divergence. The existence of the modern phylogeographic pattern contradicts with the existence of the ancient evolutionary history of the Roseiflexus group proposed on the basis of its deep-branching phylogenetic position. These facts indicate that evolutionary rates in Roseiflexus varied over a wide range.

  18. Isolation and characterization of novel thermophilic lipase-secreting bacteria

    Directory of Open Access Journals (Sweden)

    Mohammed Rabbani

    2013-12-01

    Full Text Available The purpose of the present study was to screen and identify the lipase-producing microorganisms from various regions of Iran. Samples collected from hot spring, Persian Gulf, desert area and oil-contaminated soil, were analyzed for thermophilic extracellular-lipase producing organisms. Six strains with high activity on rhodamine B plates were selected for chemical identification and further study. Among these isolated bacteria, four strains show higher activity in pH-Stat method at 55 °C. These strains were identified by PCR amplification of 16s rRNA genes using universal primers. Fermentation increased the activity up to 50%. The growth medium, designed for lipase production, increased the activity up to 4.55 folds. The crude supernatant of ZR-5 after fermentation and separation the cells, was lyophilized and the activity was measured. Total activity of this strain was 12 kU/g that shows its potential for industrial uses. Further study is required for purification of enzyme and calculation its specific activity. Immobilization is another approach should be considered.

  19. Isolation and characterization of novel thermophilic lipase-secreting bacteria.

    Science.gov (United States)

    Rabbani, Mohammed; Bagherinejad, Mohammad Reza; Sadeghi, Hamid MirMohammad; Shariat, Ziaedin Samsam; Etemadifar, Zahra; Moazen, Fatemeh; Rahbari, Manizheh; Mafakher, Ladan; Zaghian, Saeideh

    2013-12-01

    The purpose of the present study was to screen and identify the lipase-producing microorganisms from various regions of Iran. Samples collected from hot spring, Persian Gulf, desert area and oil-contaminated soil, were analyzed for thermophilic extracellular-lipase producing organisms. Six strains with high activity on rhodamine B plates were selected for chemical identification and further study. Among these isolated bacteria, four strains show higher activity in pH-Stat method at 55 °C. These strains were identified by PCR amplification of 16s rRNA genes using universal primers. Fermentation increased the activity up to 50%. The growth medium, designed for lipase production, increased the activity up to 4.55 folds. The crude supernatant of ZR-5 after fermentation and separation the cells, was lyophilized and the activity was measured. Total activity of this strain was 12 kU/g that shows its potential for industrial uses. Further study is required for purification of enzyme and calculation its specific activity. Immobilization is another approach should be considered. PMID:24688500

  20. Single gene insertion drives bioalcohol production by a thermophilic archaeon

    Energy Technology Data Exchange (ETDEWEB)

    Basen, M; Schut, GJ; Nguyen, DM; Lipscomb, GL; Benn, RA; Prybol, CJ; Vaccaro, BJ; Poole, FL; Kelly, RM; Adams, MWW

    2014-12-09

    Bioethanol production is achieved by only two metabolic pathways and only at moderate temperatures. Herein a fundamentally different synthetic pathway for bioalcohol production at 70 degrees C was constructed by insertion of the gene for bacterial alcohol dehydrogenase (AdhA) into the archaeon Pyrococcus furiosus. The engineered strain converted glucose to ethanol via acetate and acetaldehyde, catalyzed by the host-encoded aldehyde ferredoxin oxidoreductase (AOR) and heterologously expressed AdhA, in an energy-conserving, redox-balanced pathway. Furthermore, the AOR/AdhA pathway also converted exogenously added aliphatic and aromatic carboxylic acids to the corresponding alcohol using glucose, pyruvate, and/or hydrogen as the source of reductant. By heterologous coexpression of a membrane-bound carbon monoxide dehydrogenase, CO was used as a reductant for converting carboxylic acids to alcohols. Redirecting the fermentative metabolism of P. furiosus through strategic insertion of foreign genes creates unprecedented opportunities for thermophilic bioalcohol production. Moreover, the AOR/AdhA pathway is a potentially game-changing strategy for syngas fermentation, especially in combination with carbon chain elongation pathways.

  1. A novel thermophilic endoglucanase from a mesophilic fungus Fusarium oxysporum

    Institute of Scientific and Technical Information of China (English)

    LIU Shuyan; DUAN Xinyuan; LU Xuemei; GAO Peiji

    2006-01-01

    A novel thermophilic endoglucanase (EGt) was extracted from a mesophilic fungus (Fusarium oxysporum L19). We invoked conventional kinetic enzyme reactions using the sodium salt of carboxymethyl cellulose (CMC-Na) as substrate. EGt displayed optimal activity at 75℃ when kept running 30 min in the temperature range of 30―85℃. Thermal stability curve measured at 70℃ suggested that its half-life time is 15.1 min. The activity was enhanced in the presence of Co2+ or Mg2+ but inhibited by Pb2+ and Fe3+. Moreover, N-bromosuccinimide (NBS) modification resulted in a complete loss of EGt activity, suggesting that tryptophan residues 5 be involved in the enzyme active site. Amino acid composition analysis demonstrated that EGt contains more proline residues. EGt lacks activity towards p-nitrophenyl cellobiose (pNPC). The N-terminal amino acid sequence of EGt is SYRVPAANGFPNP- DASQEKQ, and the gene of EGt was sequenced and analyzed. Extensive sequence alignments failed to show any homology between EGt and any known endoglucanases. This is the first report addressing the thermal adaptation of a cellulolytic enzyme from the mesophilic fungus F. oxysporum. 5be the expression of multiple isoenzyme in an organism helps it adapt to complex living environments.

  2. Biogeography of thermophilic phototrophic bacteria belonging to Roseiflexus genus.

    Science.gov (United States)

    Gaisin, Vasil A; Grouzdev, Denis S; Namsaraev, Zorigto B; Sukhacheva, Marina V; Gorlenko, Vladimir M; Kuznetsov, Boris B

    2016-03-01

    Isolated environments such as hot springs are particularly interesting for studying the microbial biogeography. These environments create an 'island effect' leading to genetic divergence. We studied the phylogeographic pattern of thermophilic anoxygenic phototrophic bacteria, belonging to the Roseiflexus genus. The main characteristic of the observed pattern was geographic and geochronologic fidelity to the hot springs within Circum-Pacific and Alpine-Himalayan-Indonesian orogenic belts. Mantel test revealed a correlation between genetic divergence and geographic distance among the phylotypes. Cluster analysis revealed a regional differentiation of the global phylogenetic pattern. The phylogeographic pattern is in correlation with geochronologic events during the break up of Pangaea that led to the modern configuration of continents. To our knowledge this is the first geochronological scenario of intercontinental prokaryotic taxon divergence. The existence of the modern phylogeographic pattern contradicts with the existence of the ancient evolutionary history of the Roseiflexus group proposed on the basis of its deep-branching phylogenetic position. These facts indicate that evolutionary rates in Roseiflexus varied over a wide range. PMID:26826142

  3. Kinetics of inactivation of indicator pathogens during thermophilic anaerobic digestion.

    Science.gov (United States)

    Popat, Sudeep C; Yates, Marylynn V; Deshusses, Marc A

    2010-12-01

    Thermophilic anaerobic sludge digestion is a promising process to divert waste to beneficial use, but an important question is the required temperature and holding time to achieve a given degree of pathogen inactivation. In this study, the kinetics of inactivation of Ascaris suum and vaccine strain poliovirus type 1 (PVS-1), selected as indicators for helminth ova and enteric viruses respectively, were determined during anaerobic digestion at temperatures ranging from 51 to 56 °C. Inactivation of both indicator organisms was fast with greater than two log reductions achieved within 2 h for A. suum and three log reductions for PVS-1, suggesting that the current U.S. regulations are largely conservative. The first-order inactivation rate constants k followed Arrhenius relationship with activation energies of 105 and 39 KJ mol(-1) for A. suum and PVS-1, respectively indicating that A. suum was more sensitive to temperature. Although inactivation was fast, the presence of compounds in the sludge that are known to be protective of pathogen inactivation was observed, suggesting that composition-dependent time-temperature relationships are necessary. PMID:20692678

  4. Characterization of thermophilic consortia from two souring oil reservoirs.

    Science.gov (United States)

    Mueller, R F; Nielsen, P H

    1996-09-01

    The microbial consortia from produced water at two different oil fields in Alaska (Kuparuk) and the North Sea (Ninian) were investigated for sulfate-reducing and methanogenic activity over a range of temperatures and for a variety of substrates. The consortia were sampled on site, and samples were either incubated on site at 60(deg)C with various substrates or frozen for later incubation and analyses. Temperature influenced the rates of sulfate reduction, hydrogen sulfide production, and substrate oxidation, as well as the cell morphology. The highest rates of sulfate reduction and substrate oxidation were found between 50 and 60(deg)C. Formate and n-butyrate were the most favorable electron donors at any tested temperature. Acetate was utilized at 35(deg)C but not at 50 or 70(deg)C and was produced at 60(deg)C. This indicates that the high levels of acetate found in produced water from souring oil formations are due mainly to an incomplete oxidation of volatile fatty acids to acetate. The cell size distribution of the microbial consortium indicated a nonuniform microbial composition in the original sample from the Kuparuk field. At different temperatures, different microbial morphologies and physiologies were observed. Methane-producing activity at thermophilic temperatures (60(deg)C) was found only for the Kuparuk consortium when hydrogen and carbon dioxide were present. No methane production from acetate was observed. Suppression of methanogenic activity in the presence of sulfate indicated a competition with sulfate-reducing bacteria for hydrogen.

  5. Involvement of thermophilic archaea in the biocorrosion of oil pipelines.

    Science.gov (United States)

    Davidova, Irene A; Duncan, Kathleen E; Perez-Ibarra, B Monica; Suflita, Joseph M

    2012-07-01

    Two thermophilic archaea, strain PK and strain MG, were isolated from a culture enriched at 80°C from the inner surface material of a hot oil pipeline. Strain PK could ferment complex organic nitrogen sources (e.g. yeast extract, peptone, tryptone) and was able to reduce elemental sulfur (S°), Fe(3+) and Mn(4+) . Phylogenetic analysis revealed that the organism belonged to the order Thermococcales. Incubations of this strain with elemental iron (Fe°) resulted in the abiotic formation of ferrous iron and the accumulation of volatile fatty acids during yeast extract fermentation. The other isolate, strain MG, was a H(2) :CO(2) -utilizing methanogen, phylogenetically affiliated with the genus Methanothermobacter family. Co-cultures of the strains grew as aggregates that produced CH(4) without exogenous H(2) amendment. The co-culture produced the same suite but greater concentrations of fatty acids from yeast extract than did strain PK alone. Thus, the physiological characteristics of organisms both alone and in combination could conceivably contribute to pipeline corrosion. The Thermococcus strain PK could reduce elemental sulfur to sulfide, produce fatty acids and reduce ferric iron. The hydrogenotrophic methanogen strain MG enhanced fatty acid production by fermentative organisms but could not couple the dissolution Fe° with the consumption of water-derived H(2) like other methanogens.

  6. Thermophilic hydrogen fermentation from Korean rice straw by Thermotoga neapolitana

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Tam-Anh D.; Kim, Kyoung-Rok; Sim, Sang Jun [Department of Chemical Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kim, Mi Sun [Bioenergy Research Center, Korea Institute of Energy Research, Daejeon 305-343 (Korea, Republic of)

    2010-12-15

    Rice straw, a low-cost lignocellulosic biomass was used as feedstock for thermophilic hydrogen fermentation by Thermotoga neapolitana. Hydrogen production, the growth and cellulose digestibility of the hyperthermophile in batch mode from untreated as well as chemically pretreated (ammonia and dilute sulfuric acid) Korean rice straws were investigated. Pretreatment method using combination of 10% ammonia and 1.0% dilute sulfuric acid was developed to increase the digestibility of rice straw for the hyperthermophilic H{sub 2} fermentation and to decrease the time consumption. In a typical fermentation using raw rice straw, 29% of the substrate was digested and 2.3 mmol H{sub 2}/g straw of hydrogen yield was consistently obtained. Compared with the pretreatments using only ammonia or dilute sulfuric acid, the combined pretreatment method using both chemical agents significantly increases the digestibility of rice straw with 85.4% of substrate consumption. H{sub 2} production on rice straw from this combined pretreatment showed the highest yield (2.7 mmol H{sub 2}/g straw) and the highest sugar conversions (72.9% of glucose and 95.7% of xylose). (author)

  7. Modeling temperature variations in a pilot plant thermophilic anaerobic digester.

    Science.gov (United States)

    Valle-Guadarrama, Salvador; Espinosa-Solares, Teodoro; López-Cruz, Irineo L; Domaschko, Max

    2011-05-01

    A model that predicts temperature changes in a pilot plant thermophilic anaerobic digester was developed based on fundamental thermodynamic laws. The methodology utilized two simulation strategies. In the first, model equations were solved through a searching routine based on a minimal square optimization criterion, from which the overall heat transfer coefficient values, for both biodigester and heat exchanger, were determined. In the second, the simulation was performed with variable values of these overall coefficients. The prediction with both strategies allowed reproducing experimental data within 5% of the temperature span permitted in the equipment by the system control, which validated the model. The temperature variation was affected by the heterogeneity of the feeding and extraction processes, by the heterogeneity of the digestate recirculation through the heating system and by the lack of a perfect mixing inside the biodigester tank. The use of variable overall heat transfer coefficients improved the temperature change prediction and reduced the effect of a non-ideal performance of the pilot plant modeled.

  8. Selecting the best inoculation for anaerobic thermophilic treatment in sewage plants; Seleccion de inoculo para el tratamiento anaerobio termofilico de lodos de depuradora

    Energy Technology Data Exchange (ETDEWEB)

    Riau, V.; Rubia, M. A. de la; Forster, T.; Perez, M.

    2009-07-01

    The objective of the present work is to propose a suitable method to obtain an thermophilic inoculum source able for the anaerobic thermophilic digestion of sludge raw. Also, the acclimatization period to the temperature and the substrate is study as well as the thermophilic process at different solids retention of solids is analyzed. (Author) 18 refs.

  9. Complete genome sequence of Geobacillus thermoglucosidans TNO-09.020, a thermophilic sporeformer associated with a dairy-processing environment

    NARCIS (Netherlands)

    Zhao, Y.; Caspers, M.P.; Abee, T.; Siezen, R.J.; Kort, R.

    2012-01-01

    Thermophilic spore-forming bacteria are a common cause of contamination in dairy products. We isolated the thermophilic strain Geobacillus thermoglucosidans TNO-09.020 from a milk processing plant and report the complete genome of a dairy plant isolate consisting of a single chromosome of 3.75 Mb.

  10. Complete Genome Sequence of Geobacillus thermoglucosidans TNO-09.020, a Thermophilic Sporeformer Associated with a Dairy-Processing Environment.

    NARCIS (Netherlands)

    Zhao, Y.; Caspers, M.P.; Abee, T.; Siezen, R.J.; Kort, R.

    2012-01-01

    Thermophilic spore-forming bacteria are a common cause of contamination in dairy products. We isolated the thermophilic strain Geobacillus thermoglucosidans TNO-09.020 from a milk processing plant and report the complete genome of a dairy plant isolate consisting of a single chromosome of 3.75 Mb.

  11. Complete genome sequence of Geobacillus thermoglucosidans TNO-09.020, a thermophilic sporeformer associated with a dairy-processing environment

    NARCIS (Netherlands)

    Zhao, Y.; Caspers, M.P.; Abee, T.; Siezen, R.J.; Kort, R.

    2012-01-01

    Thermophilic spore-forming bacteria are a common cause of contamination in dairy products. We isolated the thermophilic strain Geobacillus thermoglucosidans TNO-09.020 from a milk processing plant and report the complete genome of a dairy plant isolate consisting of a single chromosome of 3.75 Mb. ©

  12. Group-specific 16S rRNA-targeted oligonucleotide probes to identify thermophilic bacteria in marine hydrothermal vents

    NARCIS (Netherlands)

    Harmsen, HJM; Prieur, D; Jeanthon, C

    1997-01-01

    Four 16S rRNA-targeted oligonucleotide probes were designed for the detection of thermophilic members of the domain Bacteria known to thrive in marine hydrothermal systems, We developed and characterized probes encompassing most of the thermophilic members of the genus Bacillus, most species of the

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

    NARCIS (Netherlands)

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

    2003-01-01

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

  14. Methanol coneversion by a novel thermophilic homoacetogenic bacterium Moorella mulderi sp.nov. isolated from a bioreactor

    NARCIS (Netherlands)

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

    2003-01-01

    A thermophilic, anaerobic, spore-forming bacterium (strain TMS) was isolated from a thermophilic bioreactor operated at 65 degreesC with methanol as the energy source. Cells were gram-positive straight rods, 0.4-0.6 mum x 2-8 mum, growing as single cells or in pairs. The temperature range for growth

  15. Insight into structure and assembly of the nuclear pore complex by utilizing the genome of a eukaryotic thermophile

    DEFF Research Database (Denmark)

    Amlacher, Stefan; Sarges, Phillip; Flemming, Dirk;

    2011-01-01

    Despite decades of research, the structure and assembly of the nuclear pore complex (NPC), which is composed of ~30 nucleoporins (Nups), remain elusive. Here, we report the genome of the thermophilic fungus Chaetomium thermophilum (ct) and identify the complete repertoire of Nups therein. The the...... of a thermophilic eukaryote for studying complex molecular machines....

  16. Characteristics of Recombinant Phytase (rSt-Phy) of the Thermophilic mold Sporotrichum thermophile and its applicability in dephytinizing foods.

    Science.gov (United States)

    Ranjan, Bibhuti; Singh, Bijender; Satyanarayana, T

    2015-12-01

    Sporotrichum thermophile produces very low titres of phytase (St-Phy) extracellularly, which is acidstable, thermostable, and protease insensitive with broad substrate specificity, and therefore, the gene encoding phytase (St-Phy) has been cloned and expressed in E. coli. The purified recombinant phytase (rSt-Phy) has the molecular mass of 55 kDa with Km and Vmax (calcium phytate), kcat and kcat/Km of 0.143 mM, 185.05 nmoles mg(-1)  s(-1), 5.1 × 10(3) s(-1), and 3.5 × 10(7) M(-1) s(-1), respectively. Mg(2+) and Ba(2+) display slight stimulatory effect on the enzyme, while it is inhibited by other ions to a varied extent. The enzyme is also inhibited by chaotropic agents (guanidinium hydrochloride, potassium iodide, and urea), Woodward's reagent K, and 2,3-butanedione but resistant to both pepsin and trypsin. The rSt-Phy is useful in dephytinization of tandoori and naan (unleavened flat Indian breads), and bread, liberating soluble inorganic phosphate that mitigates anti-nutrient effects of phytic acid. PMID:26433599

  17. Influence of temperature fluctuation on thermophilic anaerobic digestion of municipal organic solid waste

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A laboratory-scale experiment was carried out to assess the influence of temperature fluctuation on thermophilic anaerobic digestion of municipal organic solid waste (MOSW). Heating failure was simulated by decreasing temperature suddenly from 55 ℃ to 20 ℃ suddenly; 2 h time is needed for temperature decrease and recovery. Under the conditions ofS.0 g/(L·d) and 15 d respectively for MOSW load and retention time, following results were noted: (1) biogas production almost stopped and VFA (volatile fatty acid) accumulated rapidly, accompanied by pH decrease; (2) with low temperature (20 ℃) duration of 1, 5, 12 and 24 h, it took 3, 11, 56 and 72 h for the thermophilic anaerobic digestion system to reproduce methane after temperature fluctuation;(3) the longer the low temperature interval lasted, the more the methanogenic bacteria would decay; hydrolysis, acidification and methanogenesis were all influenced by temperature fluctuation; (4) the thermophilic microorganisms were highly resilient to temperature fluctuation.

  18. Over-expression of carboxypeptidase of extreme thermophile pyrococcus furiosus in escherichia coli

    International Nuclear Information System (INIS)

    Thermophiles and extreme thermophiles are potential source of thermostable proteases for economical application. This study deals with cloning and over-expression of a carboxypeptidase (CBP) from the extreme thermophile archaeon Pyrococcus furiosus in E. coli. Using the forward and the reverse primers designed according to the putative CBP gene sequence analysed from the published genome sequence of P. furiosus, 1.5 kb fragment of CBP gene was PCR amplified. After TA-cloning in pTZ57R/T vector, the gene was ligated into pET-22b(+) and the recombinant plasmid thus obtained was used to transform E. coli BL21 (DE3)RIPL. On induction with IPTG for 6-8 hours CBP was expressed up to 30% of the total cell proteins. The enzyme, however, was expressed in an insoluble form which was refolded to an active state by treatment with urea. (author)

  19. Thermophilic Sulfate Reduction in Hydrothermal Sediment of Lake Tanganyika, East-Africa

    DEFF Research Database (Denmark)

    ELSGAARD, L.; PRIEUR, D.; MUKWAYA, GM;

    1994-01-01

    In environments with temperatures above 60 degrees C, thermophilic prokaryotes are the only metabolically active life-forms. By using the (SO42-)-S-35 tracer technique, we studied the activity of sulfate-reducing microorganisms (SRM) in hot sediment from a hydrothermal vent site in the northern...... population of SRM in the hydrothermal sediment. Thermophilic sulfate reduction had a pH optimum of about 7 and was completely inhibited at pH 8.8 to 9.2. SRM could be enriched from hydrothermal chimney and sediment samples at 60 and 75 degrees C. In lactate-grown enrichments, sulfide production occurred...... at up to 70 and 75 degrees C, with optima at 63 and 71 degrees C, respectively. Several sporulating thermophilic enrichments were morphologically similar to Desulfotomaculum spp. Dissimilatory sulfate reduction in the studied hydrothermal area of Lake Tanganyika apparently has an upper temperature limit...

  20. Metagenomics of Thermophiles with a Focus on Discovery of Novel Thermozymes

    Science.gov (United States)

    DeCastro, María-Eugenia; Rodríguez-Belmonte, Esther; González-Siso, María-Isabel

    2016-01-01

    Microbial populations living in environments with temperatures above 50°C (thermophiles) have been widely studied, increasing our knowledge in the composition and function of these ecological communities. Since these populations express a broad number of heat-resistant enzymes (thermozymes), they also represent an important source for novel biocatalysts that can be potentially used in industrial processes. The integrated study of the whole-community DNA from an environment, known as metagenomics, coupled with the development of next generation sequencing (NGS) technologies, has allowed the generation of large amounts of data from thermophiles. In this review, we summarize the main approaches commonly utilized for assessing the taxonomic and functional diversity of thermophiles through metagenomics, including several bioinformatics tools and some metagenome-derived methods to isolate their thermozymes. PMID:27729905

  1. Competition of CO and H2 for Active Oxygen Species during the Preferential CO Oxidation (PROX on Au/TiO2 Catalysts

    Directory of Open Access Journals (Sweden)

    Yeusy Hartadi

    2016-01-01

    Full Text Available Aiming at an improved mechanistic understanding of the preferential oxidation of CO on supported Au catalysts, we have investigated the competition between CO and H2 for stable, active oxygen (Oact species on a Au/TiO2 catalyst during the simultaneous exposure to CO and H2 with various CO/H2 ratios at 80 °C and 400 °C by quantitative temporal analysis of products (TAP reactor measurements. It is demonstrated that, at both higher and lower temperature, the maximum amount of active oxygen removal is (i independent of the CO/H2 ratio and (ii identical to the amount of active oxygen removal by CO or H2 alone. Hence, under preferential CO oxidation (PROX reaction conditions, in the simultaneous presence of CO and H2, CO and H2 compete for the same active oxygen species. In addition, also the dependency of the selectivity towards CO oxidation on the CO/H2 ratio was evaluated from these measurements. Consequences of these findings on the mechanistic understanding of the PROX reaction on Au/TiO2 will be discussed.

  2. Biomolecule-assisted synthesis of In(OH)₃ nanocubes and In₂O₃ nanoparticles: photocatalytic degradation of organic contaminants and CO oxidation.

    Science.gov (United States)

    Nayak, Arpan Kumar; Lee, Seungwon; Sohn, Youngku; Pradhan, Debabrata

    2015-12-01

    The synthesis of nanostructured materials without any hazardous organic chemicals and expensive capping reagents is one of the challenges in nanotechnology. Here we report on the L-arginine (a biomolecule)-assisted synthesis of single crystalline cubic In(OH)3 nanocubes of a size in the range of 30-60 nm along the diagonal using hydrothermal methods. Upon calcining at 750 °C for 1 h in air, In(OH)3 nanocubes are transformed into In2O3 nanoparticles (NPs) with voids. The morphology transformation and formation of voids with the increase of the calcination temperature is studied in detail. The possible mechanism of the voids' formation is discussed on the basis of the Kirkendall effect. The photocatalytic properties of In(OH)3 nanocubes and In2O3 NPs are studied for the degradation of rhodamin B and alizarin red S. Furthermore, the CO oxidation activity of In(OH)3 nanocubes and In2O3 NPs is examined. The photocatalytic and CO oxidation activity are measured to be higher for In2O3 NPs than for In(OH)3 nanocubes. This is attributed to the lower energy gap and higher specific surface area of the former. The present green synthesis has potential for the synthesis of other inorganic nanomaterials.

  3. Biomolecule-assisted synthesis of In(OH)3 nanocubes and In2O3 nanoparticles: photocatalytic degradation of organic contaminants and CO oxidation

    Science.gov (United States)

    Nayak, Arpan Kumar; Lee, Seungwon; Sohn, Youngku; Pradhan, Debabrata

    2015-12-01

    The synthesis of nanostructured materials without any hazardous organic chemicals and expensive capping reagents is one of the challenges in nanotechnology. Here we report on the L-arginine (a biomolecule)-assisted synthesis of single crystalline cubic In(OH)3 nanocubes of a size in the range of 30-60 nm along the diagonal using hydrothermal methods. Upon calcining at 750 °C for 1 h in air, In(OH)3 nanocubes are transformed into In2O3 nanoparticles (NPs) with voids. The morphology transformation and formation of voids with the increase of the calcination temperature is studied in detail. The possible mechanism of the voids’ formation is discussed on the basis of the Kirkendall effect. The photocatalytic properties of In(OH)3 nanocubes and In2O3 NPs are studied for the degradation of rhodamin B and alizarin red S. Furthermore, the CO oxidation activity of In(OH)3 nanocubes and In2O3 NPs is examined. The photocatalytic and CO oxidation activity are measured to be higher for In2O3 NPs than for In(OH)3 nanocubes. This is attributed to the lower energy gap and higher specific surface area of the former. The present green synthesis has potential for the synthesis of other inorganic nanomaterials.

  4. Design of a core–shell Pt–SiO2 catalyst in a reverse microemulsion system: Distinctive kinetics on CO oxidation at low temperature

    KAUST Repository

    Al Mana, Noor

    2016-06-28

    The mechanism of formation of Pt@SiO2 as a model of core–shell nanoparticles via water-in-oil reverse microemulsions was studied in detail. By controlling the time of growth of Pt precursors, Pt(OH)x, after hydrolysis in NH3 aq. before adding SiO2 precursor (TEOS), Pt nanoparticles with a narrow size distribution were produced, from ultrafine metal nanoparticles (<1 nm) to 6 nm nanocrystals. Separately, the thickness of SiO2 was controllably synthesized from 1 to 15 nm to yield different Pt@SiO2 materials. The Pt@SiO2 core–shell catalysts exhibited a higher rate of CO oxidation by one order of magnitude with a positive order regarding CO pressure. The SiO2 shell did not perturb the Pt chemical nature, but it provided different coverage of CO in steady-state CO oxidation. © 2016 Elsevier Inc.

  5. Biogas production and methanogenic archaeal community in mesophilic and thermophilic anaerobic co-digestion processes.

    Science.gov (United States)

    Yu, D; Kurola, J M; Lähde, K; Kymäläinen, M; Sinkkonen, A; Romantschuk, M

    2014-10-01

    Over 258 Mt of solid waste are generated annually in Europe, a large fraction of which is biowaste. Sewage sludge is another major waste fraction. In this study, biowaste and sewage sludge were co-digested in an anaerobic digestion reactor (30% and 70% of total wet weight, respectively). The purpose was to investigate the biogas production and methanogenic archaeal community composition in the anaerobic digestion reactor under meso- (35-37 °C) and thermophilic (55-57 °C) processes and an increasing organic loading rate (OLR, 1-10 kg VS m(-3) d(-1)), and also to find a feasible compromise between waste treatment capacity and biogas production without causing process instability. In summary, more biogas was produced with all OLRs by the thermophilic process. Both processes showed a limited diversity of the methanogenic archaeal community which was dominated by Methanobacteriales and Methanosarcinales (e.g. Methanosarcina) in both meso- and thermophilic processes. Methanothermobacter was detected as an additional dominant genus in the thermophilic process. In addition to operating temperatures, the OLRs, the acetate concentration, and the presence of key substrates like propionate also affected the methanogenic archaeal community composition. A bacterial cell count 6.25 times higher than archaeal cell count was observed throughout the thermophilic process, while the cell count ratio varied between 0.2 and 8.5 in the mesophilic process. This suggests that the thermophilic process is more stable, but also that the relative abundance between bacteria and archaea can vary without seriously affecting biogas production.

  6. Interconversion of functional motions between mesophilic and thermophilic adenylate kinases.

    Directory of Open Access Journals (Sweden)

    Michael D Daily

    2011-07-01

    Full Text Available Dynamic properties are functionally important in many proteins, including the enzyme adenylate kinase (AK, for which the open/closed transition limits the rate of catalytic turnover. Here, we compare our previously published coarse-grained (double-well Gō simulation of mesophilic AK from E. coli (AKmeso to simulations of thermophilic AK from Aquifex aeolicus (AKthermo. In AKthermo, as with AKmeso, the LID domain prefers to close before the NMP domain in the presence of ligand, but LID rigid-body flexibility in the open (O ensemble decreases significantly. Backbone foldedness in O and/or transition state (TS ensembles increases significantly relative to AKmeso in some interdomain backbone hinges and within LID. In contact space, the TS of AKthermo has fewer contacts at the CORE-LID interface but a stronger contact network surrounding the CORE-NMP interface than the TS of AKmeso. A "heated" simulation of AKthermo at 375K slightly increases LID rigid-body flexibility in accordance with the "corresponding states" hypothesis. Furthermore, while computational mutation of 7 prolines in AKthermo to their AKmeso counterparts produces similar small perturbations, mutation of these sites, especially positions 8 and 155, to glycine is required to achieve LID rigid-body flexibility and hinge flexibilities comparable to AKmeso. Mutating the 7 sites to proline in AKmeso reduces some hinges' flexibilities, especially hinge 2, but does not reduce LID rigid-body flexibility, suggesting that these two types of motion are decoupled in AKmeso. In conclusion, our results suggest that hinge flexibility and global functional motions alike are correlated with but not exclusively determined by the hinge residues. This mutational framework can inform the rational design of functionally important flexibility and allostery in other proteins toward engineering novel biochemical pathways.

  7. Interaction of gaseous aromatic and aliphatic compounds in thermophilic biofilters.

    Science.gov (United States)

    Hu, Qing-yuan; Wang, Can

    2015-12-30

    Two thermophilic biofilters were applied in treating a mixture of gaseous aromatic (benzene) and aliphatic compounds (hexane) to evaluate the interaction of the compounds. The performance of the biofilters was investigated in terms of removal efficiencies, elimination capacity, kinetic analysis, interaction indices, and microbial metabolic characteristics. Results showed that the removal performance of benzene was unaffected by the addition of hexane. The removal efficiencies of benzene were maintained at approximately 80% and the biodegradation rate constant was maintained at 120 h(-1). However, the removal efficiencies of hexane decreased significantly from 60% to 20% and the biodegradation rate constant exhibited a distinct decrease from 93.59 h(-1) to 56.32 h(-1). The interaction index of benzene with the addition of hexane was -0.029, which indicated that hexane had little effect on the degradation of benzene. By contrast, the interaction index of hexane by benzene was -0.557, which showed that benzene inhibited the degradation of hexane significantly. Similar conclusions were obtained about the substrate utilization. Moreover, the utilization degree of carbon sources and the microbial metabolic activities in the biofilter treating hexane were significantly improved with the addition of benzene, whereas the addition of hexane had a slight effect on the microbial communities in the biofilter treating benzene. Conclusions could be obtained that when mixtures of benzene and hexane were treated using biofilters, the degradation of benzene, which was more easily degradable, was dominant and unaffected; whereas the degradation of hexane, which was less easily degradable, was inhibited because of the changing of microbes.

  8. Isolation and identification of the thermophilic alkaline desulphuricant strain

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A desulfurization strain that belongs to the thermophilic alkaline desulphuricant is designated as strain GDJ-3 and isolated from Inner Mongolia, China. The colony of the strain shows tiny, yellow, or white-yellow, and it becomes henna with the protracting of cultivated time. The cells are bacilliform (0.3 -0.6 × 1.0-1.2 μm), motive, and Gram negative. The strain GDJ-3 is able to utilize respectively the thiosulphate, sulfate, sulfite, or sulfide as sulfur source, utilize the carbon dioxide as the carbon source, and utilize the ammonium or nitrate as the nitrogen source. According to GenBank data, 16s RNA results of GDJ-3 are in good agreement with Alpha proteobacterrium sp. (97%) and Ochrobactrum sp. (98%). For GDJ-3, the optimum growth temperature is at 45℃, the optimum pH is at 8.5-8.8, and the optimum rocking speed of sorting table is at 150 r/min. Under the optimum culture condition, the cells of the strain can live for about 18 h. In the desulfurization solution, which is prepared according to the composition of DDS solution, the objectionable constituents of sodium thiosulphate and sodium sulfide were added factitiously, and the bacterial cell concentration was set at 107/mL. After the regeneration of the above desulfurization solution by the strain cells, the concentration of sodium thiosulphate was decreased by 14.75 g/L (percentage loss of content 13.21%), the concentration of sodium sulfide was decreased by 0.76 g/L (percentage loss of content 87.36%) in the desulfurization solution in 9.5 hours, and sulfur appeared. Maybe, this kind of strain can be used as the regeneration’s bacterial source of DDS solution.

  9. Experimental evidence for aerobic bio-denitrification

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Nitrate pollution of groundwater is paid more and more attention for its hazardous to environments and human health. A strain of DN11 was isolated from soil and used in the laboratory columns filled with various media for nitrate removal. The experimental results showed that DN11could reduce nitrate at different rates in different media under the aerobic condition. The mechanism for nitrate removal with DN11 is explained meanwhile.

  10. Acute effects of aerobic exercise promote learning

    OpenAIRE

    Renza Perini; Marta Bortoletto; Michela Capogrosso; Anna Fertonani; Carlo Miniussi

    2016-01-01

    The benefits that physical exercise confers on cardiovascular health are well known, whereas the notion that physical exercise can also improve cognitive performance has only recently begun to be explored and has thus far yielded only controversial results. In the present study, we used a sample of young male subjects to test the effects that a single bout of aerobic exercise has on learning. Two tasks were run: the first was an orientation discrimination task involving the primary visual cor...

  11. Complete genome sequence, metabolic model construction and phenotypic characterization of Geobacillus LC300, an extremely thermophilic, fast growing, xylose-utilizing bacterium.

    Science.gov (United States)

    Cordova, Lauren T; Long, Christopher P; Venkataramanan, Keerthi P; Antoniewicz, Maciek R

    2015-11-01

    We have isolated a new extremely thermophilic fast-growing Geobacillus strain that can efficiently utilize xylose, glucose, mannose and galactose for cell growth. When grown aerobically at 72 °C, Geobacillus LC300 has a growth rate of 2.15 h(-1) on glucose and 1.52 h(-1) on xylose (doubling time less than 30 min). The corresponding specific glucose and xylose utilization rates are 5.55 g/g/h and 5.24 g/g/h, respectively. As such, Geobacillus LC300 grows 3-times faster than E. coli on glucose and xylose, and has a specific xylose utilization rate that is 3-times higher than the best metabolically engineered organism to date. To gain more insight into the metabolism of Geobacillus LC300 its genome was sequenced using PacBio's RS II single-molecule real-time (SMRT) sequencing platform and annotated using the RAST server. Based on the genome annotation and the measured biomass composition a core metabolic network model was constructed. To further demonstrate the biotechnological potential of this organism, Geobacillus LC300 was grown to high cell-densities in a fed-batch culture, where cells maintained a high xylose utilization rate under low dissolved oxygen concentrations. All of these characteristics make Geobacillus LC300 an attractive host for future metabolic engineering and biotechnology applications.

  12. Nitrification and aerobic denitrification in anoxic-aerobic sequencing batch reactor.

    Science.gov (United States)

    Alzate Marin, Juan C; Caravelli, Alejandro H; Zaritzky, Noemí E

    2016-01-01

    The aim of this study was to evaluate the feasibility of achieving nitrogen (N) removal using a lab-scale sequencing batch reactor (SBR) exposed to anoxic/aerobic (AN/OX) phases, focusing to achieve aerobic denitrification. This process will minimize emissions of N2O greenhouse gas. The effects of different operating parameters on the reactor performance were studied: cycle duration, AN/OX ratio, pH, dissolved oxygen concentration (DOC), and organic load. The highest inorganic N removal (NiR), close to 70%, was obtained at pH=7.5, low organic load (440mgCOD/(Lday)) and high aeration given by 12h cycle, AN/OX ratio=0.5:1.0 and DOC higher than 4.0mgO2/L. Nitrification followed by high-rate aerobic denitrification took place during the aerobic phase. Aerobic denitrification could be attributed to Tetrad-forming organisms (TFOs) with phenotype of glycogen accumulating organisms using polyhydroxyalkanoate and/or glycogen storage. The proposed AN/OX system constitutes an eco-friendly N removal process providing N2 as the end product. PMID:26512862

  13. Isolation of cultivable thermophilic lactic acid bacteria from cheeses made with mesophilic starter and molecular comparison with dairy-related Lactobacillus helveticus strains

    DEFF Research Database (Denmark)

    Jensen, Marie Elisabeth Penderup; Ardö, Ylva Margareta; Vogensen, Finn Kvist

    2009-01-01

    Aims: To isolate cultivable thermophilic lactic acid bacteria from cheeses made with mesophilic starter and compare them with dairy-related Lactobacillus helveticus strains using molecular typing methods. Methods and Results: The number of thermophilic bacteria in seven commercial cheeses manufac...... and thermophilic adjunct cultures by using an enumeration step. Significance and Impact of the Study: Isolation of cultivable thermophilic bacteria from ripened cheeses made with mesophilic starters offers an original source for new dairy-relevant cultures.......Aims: To isolate cultivable thermophilic lactic acid bacteria from cheeses made with mesophilic starter and compare them with dairy-related Lactobacillus helveticus strains using molecular typing methods. Methods and Results: The number of thermophilic bacteria in seven commercial cheeses...... manufactured with mesophilic starters was estimated to be enumeration step in the isolation method made it possible to isolate one thermophilic strain from each of five of seven cheeses. Comparing repetitive sequence PCR (rep-PCR) profiles of the isolates with dairy...

  14. CO oxidation on PtSn nanoparticle catalysts occurs at the interface of Pt and Sn oxide domains formed under reaction conditions

    KAUST Repository

    Michalak, William D.

    2014-04-01

    The barrier to CO oxidation on Pt catalysts is the strongly bound adsorbed CO, which inhibits O2 adsorption and hinders CO2 formation. Using reaction studies and in situ X-ray spectroscopy with colloidally prepared, monodisperse ∼2 nm Pt and PtSn nanoparticle catalysts, we show that the addition of Sn to Pt provides distinctly different reaction sites and a more efficient reaction mechanism for CO oxidation compared to pure Pt catalysts. To probe the influence of Sn, we intentionally poisoned the Pt component of the nanoparticle catalysts using a CO-rich atmosphere. With a reaction environment comprised of 100 Torr CO and 40 Torr O2 and a temperature range between 200 and 300 C, Pt and PtSn catalysts exhibited activation barriers for CO2 formation of 133 kJ/mol and 35 kJ/mol, respectively. While pure Sn is readily oxidized and is not active for CO oxidation, the addition of Sn to Pt provides an active site for O2 adsorption that is important when Pt is covered with CO. Sn oxide was identified as the active Sn species under reaction conditions by in situ ambient pressure X-ray photoelectron spectroscopy measurements. While chemical signatures of Pt and Sn indicated intermixed metallic components under reducing conditions, Pt and Sn were found to reversibly separate into isolated domains of Pt and oxidic Sn on the nanoparticle surface under reaction conditions of 100 mTorr CO and 40 mTorr O2 between temperatures of 200-275 C. Under these conditions, PtSn catalysts exhibited apparent reaction orders in O2 for CO 2 production that were 0.5 and lower with increasing partial pressures. These reaction orders contrast the first-order dependence in O 2 known for pure Pt. The differences in activation barriers, non-first-order dependence in O2, and the presence of a partially oxidized Sn indicate that the enhanced activity is due to a reaction mechanism that occurs at a Pt/Sn oxide interface present at the nanoparticle surface. © 2014 Published by Elsevier Inc.

  15. Dissecting and engineering metabolic and regulatory networks of thermophilic bacteria for biofuel production.

    Science.gov (United States)

    Lin, Lu; Xu, Jian

    2013-11-01

    Interest in thermophilic bacteria as live-cell catalysts in biofuel and biochemical industry has surged in recent years, due to their tolerance of high temperature and wide spectrum of carbon-sources that include cellulose. However their direct employment as microbial cellular factories in the highly demanding industrial conditions has been hindered by uncompetitive biofuel productivity, relatively low tolerance to solvent and osmic stresses, and limitation in genome engineering tools. In this work we review recent advances in dissecting and engineering the metabolic and regulatory networks of thermophilic bacteria for improving the traits of key interest in biofuel industry: cellulose degradation, pentose-hexose co-utilization, and tolerance of thermal, osmotic, and solvent stresses. Moreover, new technologies enabling more efficient genetic engineering of thermophiles were discussed, such as improved electroporation, ultrasound-mediated DNA delivery, as well as thermo-stable plasmids and functional selection systems. Expanded applications of such technological advancements in thermophilic microbes promise to substantiate a synthetic biology perspective, where functional parts, module, chassis, cells and consortia were modularly designed and rationally assembled for the many missions at industry and nature that demand the extraordinary talents of these extremophiles.

  16. Draft Genome Sequence of a Thermophilic Desulfurization Bacterium, Geobacillus thermoglucosidasius Strain W-2

    Science.gov (United States)

    Zhu, Lin; Li, Mingchang; Guo, Shuyi

    2016-01-01

    Geobacillus thermoglucosidasius strain W-2 is a thermophilic bacterium isolated from a deep-subsurface oil reservoir in northern China, which is capable of degrading organosulfur compounds. Here, we report the draft genome sequence of G. thermoglucosidasius strain W-2, which may help to elucidate the genetic basis of biodegradation of organosulfur pollutants under heated conditions. PMID:27491977

  17. Cloning, sequencing, and sequence analysis of two novel plasmids from the thermophilic anaerobic bacterium Anaerocellum thermophilum

    DEFF Research Database (Denmark)

    Clausen, Anders; Mikkelsen, Marie Just; Schrøder, I.;

    2004-01-01

    The nucleotide sequence of two novel plasmids isolated from the extreme thermophilic anaerobic bacterium Anaerocellum thermophilum DSM6725 (A. thermophilum), growing optimally at 70degreesC, has been determined. pBAS2 was found to be a 3653 bp plasmid with a GC content of 43%, and the sequence...

  18. Dissecting and engineering metabolic and regulatory networks of thermophilic bacteria for biofuel production.

    Science.gov (United States)

    Lin, Lu; Xu, Jian

    2013-11-01

    Interest in thermophilic bacteria as live-cell catalysts in biofuel and biochemical industry has surged in recent years, due to their tolerance of high temperature and wide spectrum of carbon-sources that include cellulose. However their direct employment as microbial cellular factories in the highly demanding industrial conditions has been hindered by uncompetitive biofuel productivity, relatively low tolerance to solvent and osmic stresses, and limitation in genome engineering tools. In this work we review recent advances in dissecting and engineering the metabolic and regulatory networks of thermophilic bacteria for improving the traits of key interest in biofuel industry: cellulose degradation, pentose-hexose co-utilization, and tolerance of thermal, osmotic, and solvent stresses. Moreover, new technologies enabling more efficient genetic engineering of thermophiles were discussed, such as improved electroporation, ultrasound-mediated DNA delivery, as well as thermo-stable plasmids and functional selection systems. Expanded applications of such technological advancements in thermophilic microbes promise to substantiate a synthetic biology perspective, where functional parts, module, chassis, cells and consortia were modularly designed and rationally assembled for the many missions at industry and nature that demand the extraordinary talents of these extremophiles. PMID:23510903

  19. Start-up of a thermophilic upflow anaerobic sludge bed (UASB) reactor with mesophilic granular sludge

    Energy Technology Data Exchange (ETDEWEB)

    Lier, J.B. van; Grolle, K.C.F.; Lettinga, G. (Wageningen Agricultural Univ. (Netherlands). Dept. of Environmental Technology); Stams, A.J.M. (Wageningen Agricultural Univ. (Netherlands). Dept. of Microbiology); Conway de Macario, E. (New York State Dept. of Health, Albany, NY (United States). Wadsworth Center for Laboratories and Research State Univ. of New York, Albany, NY (United States). School of Public Health)

    1992-04-01

    Fast start-up of thermophilic upflow anaerobic sludge bed (UASB) reactors was achieved at process temperatures of 46, 55 and 64deg C, using mesophilic granular sludge as inoculum and fatty acid mixtures as feed. The start-up was brought about by increasing the temperature of mesophilic UASB reactors in a single step, which initially led to a sharp drop in the methane-production rate. Thereafter, stable thermophilic methanogenesis was achieved within a period of 1 or 2 weeks depending on the temperature of operation. Mesophilic granules functioned initially as effective carrier material for thermophilic organisms. However, long-term operation led to disintegration of the granules, resulting in wash-out of thermophilic biomass. The temperature optima for acetotrophic methanogenic activity of the sludges cultivated at 46, 55 and 64deg C, were similar, but differed significantly from the temperature optimum of the mesophilic inoculum. All the sludges examined were dominated by Methanothrix-like rods. These could be distinguished by antigenic fingerprinting into two subpopulations, one predominant at 36deg C and the other predominant at 46deg C and above. (orig.).

  20. Draft Genome Sequence of the Moderately Thermophilic Bacterium Schleiferia thermophila Strain Yellowstone (Bacteroidetes)

    OpenAIRE

    Thiel, Vera; Hamilton, Trinity L.; Tomsho, Lynn P.; Burhans, Richard; Gay, Scott E.; Ramaley, Robert F.; Stephan C Schuster; Steinke, Laurey; Bryant, Donald A.

    2014-01-01

    The draft genome sequence of the moderately thermophilic bacterium Schleiferia thermophila strain Yellowstone (Bacteroidetes), isolated from Octopus Spring (Yellowstone National Park, WY, USA) was sequenced and comprises 2,617,694 bp in 35 contigs. The draft genome is predicted to encode 2,457 protein coding genes and 37 tRNA encoding genes and two rRNA operons.

  1. Strain and bioprocess improvement of a thermophilic anaerobe for the production of ethanol from wood

    OpenAIRE

    Herring, Christopher D; Kenealy, William R.; Joe Shaw, A.; Covalla, Sean F.; Olson, Daniel G; Zhang, Jiayi; Ryan Sillers, W.; Tsakraklides, Vasiliki; Bardsley, John S.; Rogers, Stephen R.; Thorne, Philip G.; Johnson, Jessica P.; Foster, Abigail; Shikhare, Indraneel D.; Klingeman, Dawn M

    2016-01-01

    Background The thermophilic, anaerobic bacterium Thermoanaerobacterium saccharolyticum digests hemicellulose and utilizes the major sugars present in biomass. It was previously engineered to produce ethanol at yields equivalent to yeast. While saccharolytic anaerobes have been long studied as potential biomass-fermenting organisms, development efforts for commercial ethanol production have not been reported. Results Here, we describe the highest ethanol titers achieved from T. saccharolyticum...

  2. Thermophilic anaerobes in arctic marine sediments induced to mineralize complex organic matter at high temperature

    DEFF Research Database (Denmark)

    Hubert, Casey; Arnosti, Carol; Brüchert, Volker;

    2010-01-01

    Marine sediments harbour diverse populations of dormant thermophilic bacterial spores that become active in sediment incubation experiments at much higher than in situ temperature. This response was investigated in the presence of natural complex organic matter in sediments of two Arctic fjords, ...

  3. Treatment of sewage sludge in a thermophilic membrane reactor (TMR) with alternate aeration cycles.

    Science.gov (United States)

    Collivignarelli, Maria Cristina; Castagnola, Federico; Sordi, Marco; Bertanza, Giorgio

    2015-10-01

    The management of sewage sludge is becoming a more and more important issue, both at national and international level, in particular due to the uncertain recovery/disposal future options. Therefore, it is clear that the development of new technologies that can mitigate the problem at the source by reducing sludge production is necessary, such as the European Directive 2008/98/EC prescribes. This work shows the results obtained with a thermophilic membrane reactor, for processing a biological sludge derived from a wastewater treatment plant (WWTP) that treats urban and industrial wastewater. Sewage sludge was treated in a thermophilic membrane reactor (TMR), at pilot-scale (1 m(3) volume), with alternate aeration cycles. The experimentation was divided into two phases: a "startup phase" during which, starting with a psychrophilic/mesophilic biomass, thermophilic conditions were progressively reached, while feeding a highly biodegradable substrate; the obtained thermophilic biomass was then used, in the "regime phase", to digest biological sludge which was fed to the plant. Good removal yields were observed: 64% and 57% for volatile solids (VS) and total COD (CODtot), respectively, with an average hydraulic retention time (HRT) equal to 20 d, an organic loading rate (OLR) of about 1.4-1.8 kg COD m(-3) d(-1) and aeration/non aeration cycles alternated every 4 h.

  4. First Insights into the Genome of the Moderately Thermophilic Bacterium Clostridium tepidiprofundi SG 508T.

    Science.gov (United States)

    Poehlein, Anja; Friedrich, Ines; Krüger, Larissa; Daniel, Rolf

    2016-01-01

    The moderately thermophilic bacterium Clostridium tepidiprofundi is Gram-positive and belongs to clostridial cluster I. It was isolated from a hydrothermal vent chimney. Substrates utilized by C. tepidiprofundi include casein, peptone, tryptone, yeast extract, beef extract, starch, maltose, and glucose. The genome consists of one replicon (3.06 Mb). PMID:27174286

  5. First Insights into the Genome of the Moderately Thermophilic Bacterium Clostridium tepidiprofundi SG 508T

    OpenAIRE

    Poehlein, Anja; Friedrich, Ines; Krüger, Larissa; Daniel, Rolf

    2016-01-01

    The moderately thermophilic bacterium Clostridium tepidiprofundi is Gram-positive and belongs to clostridial cluster I. It was isolated from a hydrothermal vent chimney. Substrates utilized by C. tepidiprofundi include casein, peptone, tryptone, yeast extract, beef extract, starch, maltose, and glucose. The genome consists of one replicon (3.06 Mb).

  6. Growth characteristics of the thermophilic fungus Scytalidium thermophilum in relation to production of mushroom compost.

    NARCIS (Netherlands)

    Wiegant, W.M.

    1992-01-01

    Scytalidium thermophilum is an important thermophilic fungus in the production of mushroom compost. I investigated the characteristics of this organism and present a simple model with which fungal growth in compost can be described. The model is used to predict better circumstances for rapid indoor

  7. Mesophilic and thermophilic alkaline fermentation of waste activated sludge for hydrogen production: Focusing on homoacetogenesis

    DEFF Research Database (Denmark)

    Wan, Jingjing; Jing, Yuhang; Zhang, Shicheng;

    2016-01-01

    The present study compared the mesophilic and thermophilic alkaline fermentation of waste activated sludge (WAS) for hydrogen production with focus on homoacetogenesis, which mediated the consumption of H2 and CO2 for acetate production. Batch experiments showed that hydrogen yield of WAS increased...

  8. Pretreatment of wheat straw and conversion of xylose and xylan to ethanol by thermophilic anaerobic bacteria

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær; Jensen, K.; Nielsen, P.;

    1996-01-01

    . Of five different thermophilic bacteria used in this study only two strains produced ethanol with xylan as substrate, one of them being the strain A3 isolated from an Icelandic hot-spring. Probably other degradation products formed in the presence of oxygen might act as inhibitors. Adaptation...

  9. Biohydrogen Production by the Thermophilic Bacterium Caldicellulosiruptor saccharolyticus: Current Status and Perspectives

    NARCIS (Netherlands)

    Bielen, A.A.M.; Verhaart, M.R.A.; Oost, van der J.; Kengen, S.W.M.

    2013-01-01

    Caldicellulosiruptor saccharolyticus is one of the most thermophilic cellulolytic organisms known to date. This Gram-positive anaerobic bacterium ferments a broad spectrum of mono-, di- and polysaccharides to mainly acetate, CO2 and hydrogen. With hydrogen yields approaching the theoretical limit fo

  10. Electron transfer kinetics of caa(3) oxidase from Bacillus stearothermophilus : A hypothesis for thermophilicity

    NARCIS (Netherlands)

    Giuffre, A; Watmough, NJ; Giannini, S; Brunori, M; Konings, WN; Greenwood, C

    1999-01-01

    The O-2 reaction and the reverse electron transfer of the thermophilic caa, terminal oxidase of Bacillus stearothermophilus have been studied by laser flash-photolysis. The results show that both reactions, although studied at a temperature of 20 degrees C, far from the optimal temperature of > 60 d

  11. Production and partial characterisation of feruloyl esterase by Sporotrichum thermophile in solid-state fermentation

    DEFF Research Database (Denmark)

    Topakas, E.; Kalogeris, E.; Kekos, D.;

    2003-01-01

    A number of factors affecting production of feruloyl esterase an enzyme that hydrolyse ester linkages of ferulic acid (FA) in plant cell walls, by the thermophylic fungus Sporotrichum thermophile under solid state fermentation (SSF) were investigated. Initial moisture content and type of carbon...

  12. Sexual crossing of thermophilic fungus Myceliophthora heterothallica improved enzymatic degradation of sugar beet pulp

    NARCIS (Netherlands)

    Aguilar-Pontes, Maria Victoria; Zhou, Miaomiao; van der Horst, Sjors; Theelen, Bart; de Vries, Ronald P.; van den Brink, Joost

    2016-01-01

    Background Enzymatic degradation of plant biomass requires a complex mixture of many different enzymes. Like most fungi, thermophilic Myceliophthora species therefore have a large set of enzymes targeting different linkages in plant polysaccharides. The majority of these enzymes have not been functi

  13. Thermophilic Campylobacter spp. in turkey samples: evaluation of two automated enzyme immunoassays and conventional microbiological techniques

    DEFF Research Database (Denmark)

    Borck, Birgitte; Stryhn, H.; Ersboll, A.K.;

    2002-01-01

    Aims: To determine the sensitivity and specificity of two automated enzyme immunoassays (EIA), EiaFoss and Minividas, and a conventional microbiological culture technique for detecting thermophilic Campylobacter spp. in turkey samples. Methods and Results: A total of 286 samples (faecal, meat...

  14. Thermophilic fermentative hydrogen production by the newly isolated Thermoanaerobacterium thermosaccharolyticum PSU-2

    DEFF Research Database (Denmark)

    O-Thong, Sompong; Prasertsan, P.; Karakashev, Dimitar Borisov;

    2008-01-01

    A thermophilic H(2)-producing bacterial strain was isolated from a biohydrogen reactor fed with palm oil mill effluent (POME) and identified as Thermoanaerobacterium thermosaccharolyticum using 16S rRNA gene analysis. The isolated bacterium, designated as T thermosaccharolyticum PSU-2, showed...

  15. Glycolytic pathway and hydrogen yield studies of the extreme thermophile Caldicellulosiruptor saccharolyticus

    NARCIS (Netherlands)

    Vrije, de G.J.; Mars, A.E.; Budde, M.A.W.; Lai, M.H.; Dijkema, C.; Waard, de P.; Claassen, P.A.M.

    2007-01-01

    NMR analysis of 13C-labelling patterns showed that the Embden¿Meyerhof (EM) pathway is the main route for glycolysis in the extreme thermophile Caldicellulosiruptor saccharolyticus. Glucose fermentation via the EM pathway to acetate results in a theoretical yield of 4 mol of hydrogen and 2 mol of ac

  16. Optimisation of sulphate reduction in a methanol-fed thermophilic bioreactor

    NARCIS (Netherlands)

    Weijma, J.; Bots, E.A.A.; Tandlinger, G.; Stams, A.J.M.; Hulshoff Pol, L.W.; Lettinga, G.

    2002-01-01

    Several methods were tested to optimise sulphate reduction and minimise methane formation in thermophilic (65°) expanded granular sludge bed reactors fed with a medium containing sulphate and methanol. Lowering the pH from 7.5 to 6.75 resulted in a rapid decrease of methane formation and a concomita

  17. Biogas Upgrading via Hydrogenotrophic Methanogenesis in Two-Stage Continuous Stirred Tank Reactors at Mesophilic and Thermophilic Conditions

    DEFF Research Database (Denmark)

    Bassani, Ilaria; Kougias, Panagiotis; Treu, Laura;

    2015-01-01

    This study proposes an innovative setup composed by two stage reactors to achieve biogas upgrading coupling the CO2 in the biogas with external H2 and subsequent conversion into CH4 by hydrogenotrophic methanogenesis. In this configuration, the biogas produced in the first reactor was transferred...... to the second one, where H2 was injected. This configuration was tested at both mesophilic and thermophilic conditions. After H2 addition, the produced biogas was upgraded to average CH4 content of 89% in the mesophilic reactor and 85% in the thermophilic. At thermophilic conditions, a higher efficiency of CH4...

  18. Weed competitiveness and yielding ability of aerobic rice genotypes

    OpenAIRE

    Zhao, D.L.

    2006-01-01

    Keywords:    Broad-sense heritability; Crop vigour; Genetic correlation; Indirect selection index; Plant erectness; Rice germplasm; Seeding rate; Vegetative growth; Weed-suppressive ability.Aerobic rice, grown under aerobic soil conditions like maize or wheat, is an innovative way to cope with the growing demand for rice and the increasing water scarcity. Weeds are the most severe constraint to aerobic rice. The use of herbicides causes environmental pollution and induces the proliferation of...

  19. Perfection aerobic possibilities of athletes in sport dance.

    Directory of Open Access Journals (Sweden)

    Lee Bo

    2011-04-01

    Full Text Available The organized analysis to functions of the aerobic metabolism of the sport dancers. They are determined reduced components of the aerobic metabolism of partners (male and female. The motivated directivity of the training means and program for development component of the aerobic functions skilled athlete in sport dance. It is proved that loading that is used in training process by sport dances must have a character of cardiorespiratory system.

  20. The influences of microwave irradiation and polyol precursor pH on Cu/AC catalyst and its CO oxidation performance

    Energy Technology Data Exchange (ETDEWEB)

    Chuang, Kui-Hao [National Chung Hsing University, Department of Environmental Engineering (China); Shih, Kaimin [The University of Hong Kong, Department of Civil Engineering (China); Wey, Ming-Yen, E-mail: mywey@dragon.nchu.edu.tw [National Chung Hsing University, Department of Environmental Engineering (China)

    2012-10-15

    This study evaluated the effects of microwave irradiation parameters and the pH of the polyol precursor on the morphological features and catalytic performances of Cu/activated carbon (AC) catalysts. Experimental results of carbon monoxide (CO) oxidation indicated that the highest catalytic activity is achieved when the Cu/AC catalyst is prepared with microwave irradiation at 700 W for 60 s. Scanning electron microscopy revealed the presence of beneficial small copper aciculae on the Cu/AC catalyst under such a microwave irradiation scheme. Further investigation of operational parameters found that the performance of Cu/AC catalysts is enhanced by adopting a pH = 12 polyol precursor solution. With the observation that small cube copper ({approx}16 nm) aggregates form when a pH = 12 polyol precursor solution is used, this study also demonstrated the importance of controlling the morphology of metal nanoparticles on Cu/AC catalysts when using the microwave-assisted polyol method.

  1. Atomic Resolution Observation of a Size-Dependent Change in the Ripening Modes of Mass-Selected Au Nanoclusters Involved in CO Oxidation.

    Science.gov (United States)

    Hu, Kuo-Juei; Plant, Simon R; Ellis, Peter R; Brown, Christopher M; Bishop, Peter T; Palmer, Richard E

    2015-12-01

    Identifying the ripening modes of supported metal nanoparticles used in heterogeneous catalysis can provide important insights into the mechanisms that lead to sintering. We report the observation of a crossover from Smoluchowski to Ostwald ripening, under realistic reaction conditions, for monomodal populations of precisely defined gold particles in the nanometer size range, as a function of decreasing particle size. We study the effects of the CO oxidation reaction on the size distributions and atomic structures of mass-selected Au(561±13), Au(923±20) and Au(2057±45) clusters supported on amorphous carbon films. Under the same conditions, Au(561±13) and Au(923±20) clusters are found to exhibit Ostwald ripening, whereas Au(2057±45) ripens through cluster diffusion and coalescence only (Smoluchowski ripening). The Ostwald ripening is not activated by thermal annealing or heating in O2 alone. PMID:26544914

  2. Preparation,Characterization of CuO/CeO2 and Cu/CeO2 Catalysts and Their Applications in Low-Temperature CO Oxidation

    Institute of Scientific and Technical Information of China (English)

    Zheng Xiucheng; Han Dongzhan; Wang Shuping; Zhang Shoumin; Wang Shurong; Huang Weiping; Wu Shihua

    2005-01-01

    CeO2 was synthesized via sol-gel process and used as supporter to prepare CuO/CeO2, Cu/CeO2 catalysts by impregnation method. The catalytic properties and characterization of CeO2, CuO/CeO2 and Cu/CeO2 catalysts were examined by means of a microreactor-GC system, HRTEM, XRD, TPR and XPS techniques. The results show that CuO has not catalytic activity and the activity of CeO2 is quite low for CO oxidation. However, the catalytic activity of CuO/CeO2 and Cu/CeO2 catalysts increases significantly. Furthermore, the activity of CuO/CeO2 is higher than that of Cu/CeO2 catalysts.

  3. Influence of CeO2 morphology on the catalytic activity of CeO2-Pt hybrids for CO oxidation.

    Science.gov (United States)

    Singhania, Nisha; Anumol, E A; Ravishankar, N; Madras, Giridhar

    2013-11-21

    Ceria, because of its excellent redox behavior and oxygen storage capacity, is used as a catalyst for several technologically important reactions. In the present study, different morphologies of nano-CeO2 (rods, cubes, octahedra) were synthesized using the hydrothermal route. An ultrafast microwave-assisted method was used to efficiently attach Pt particles to the CeO2 polyhedra. These nanohybrids were tested as catalysts for the CO oxidation reaction. The CeO2/Pt catalyst with nanorods as the support was found to be the most active catalyst. XPS and IR spectroscopy measurements were carried out in order to obtain a mechanistic understanding and it was observed that the adsorbed carbonates with lower stability on the reactive planes of nanorods and cubes are the major contributor to this enhanced catalytic activity.

  4. Structure sensitivity in oxide catalysis: First-principles kinetic Monte Carlo simulations for CO oxidation at RuO2(111)

    International Nuclear Information System (INIS)

    We present a density-functional theory based kinetic Monte Carlo study of CO oxidation at the (111) facet of RuO2. We compare the detailed insight into elementary processes, steady-state surface coverages, and catalytic activity to equivalent published simulation data for the frequently studied RuO2(110) facet. Qualitative differences are identified in virtually every aspect ranging from binding energetics over lateral interactions to the interplay of elementary processes at the different active sites. Nevertheless, particularly at technologically relevant elevated temperatures, near-ambient pressures and near-stoichiometric feeds both facets exhibit almost identical catalytic activity. These findings challenge the traditional definition of structure sensitivity based on macroscopically observable turnover frequencies and prompt scrutiny of the applicability of structure sensitivity classifications developed for metals to oxide catalysis

  5. Nanosize Control on Porous β-MnO2 and Their Catalytic Activity in CO Oxidation and N2O Decomposition

    Directory of Open Access Journals (Sweden)

    Yu Ren

    2014-05-01

    Full Text Available A major challenge in the synthesis of porous metal oxides is the control of pore size and/or wall thickness that may affect the performance of these materials. Herein, nanoporous β-MnO2 samples were prepared using different hard templates, e.g., ordered mesoporous silica SBA-15 and KIT-6, disordered mesoporous silica, and colloidal silica. These samples were characterized by Powder X-Ray Diffraction (PXRD, Transmission Electron Microscopy (TEM, and N2 adsorption-desorption. The pore size distribution of β-MnO2 was tuned by the different hard templates and their preparation details. Catalytic activities in CO oxidation and N2O decomposition were tested and the mesoporous β-MnO2 samples demonstrated superior catalytic activities compared with their bulk counterpart.

  6. Structure sensitivity in oxide catalysis: First-principles kinetic Monte Carlo simulations for CO oxidation at RuO{sub 2}(111)

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Tongyu [Chair for Theoretical Chemistry and Catalysis Research Center, Technische Universität München, Lichtenbergstr. 4, D-85747 Garching (Germany); Reuter, Karsten, E-mail: karsten.reuter@ch.tum.de [Chair for Theoretical Chemistry and Catalysis Research Center, Technische Universität München, Lichtenbergstr. 4, D-85747 Garching (Germany); SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory and Stanford University, 443 Via Ortega, Stanford, California 94035-4300 (United States)

    2015-11-28

    We present a density-functional theory based kinetic Monte Carlo study of CO oxidation at the (111) facet of RuO{sub 2}. We compare the detailed insight into elementary processes, steady-state surface coverages, and catalytic activity to equivalent published simulation data for the frequently studied RuO{sub 2}(110) facet. Qualitative differences are identified in virtually every aspect ranging from binding energetics over lateral interactions to the interplay of elementary processes at the different active sites. Nevertheless, particularly at technologically relevant elevated temperatures, near-ambient pressures and near-stoichiometric feeds both facets exhibit almost identical catalytic activity. These findings challenge the traditional definition of structure sensitivity based on macroscopically observable turnover frequencies and prompt scrutiny of the applicability of structure sensitivity classifications developed for metals to oxide catalysis.

  7. Experimental and model analysis of the co-oxidative behavior of syngas feed in an Intermediate Temperature Solid Oxide Fuel Cell

    Science.gov (United States)

    Donazzi, A.; Rahmanipour, M.; Maestri, M.; Groppi, G.; Bardini, L.; Pappacena, A.; Boaro, M.

    2016-02-01

    By means of model analysis, we show that, in the presence of syngas, the electro-oxidation of H2 and that of CO occur in parallel and contemporarily on Samaria-doped Ceria (Sm0.2Ce0.8O1.9, SDC) Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFCs). The activation of a co-oxidative route is a most distinguishing feature of Ce-based cells, compared to traditional SOFCs. SDC electrolyte supported IT-SOFCs with Cu-Pd-CZ80 composite anodes and LSCF cathodes were tested under a wide range of operating conditions. Polarization and EIS measurements were collected at 600 °C and 650 °C with syngas mixtures (2.3-0.4H2/CO ratio), H2/N2 mixtures (from 97 to 30% H2 v/v) and CO/CO2 mixtures (from 97 to 50% CO v/v). A 1D, dynamic and heterogeneous model of the cell was applied to analyze the polarization and the EIS curves. The kinetics of the reactions of H2 electro-oxidation, CO electro-oxidation and O2 reduction were individually investigated and global power law rates were derived. The syngas experiments were simulated on a fully predictive basis and no parameter adjustment, confirming that the polarization behavior could be best reproduced exclusively by assuming the presence of the co-oxidative route. The IT-SOFCs were also exposed to biogas mixtures, revealing that the dry-reforming reaction was active.

  8. Anchoring High-Concentration Oxygen Vacancies at Interfaces of CeO(2-x)/Cu toward Enhanced Activity for Preferential CO Oxidation.

    Science.gov (United States)

    Chen, Shaoqing; Li, Liping; Hu, Wanbiao; Huang, Xinsong; Li, Qi; Xu, Yangsen; Zuo, Ying; Li, Guangshe

    2015-10-21

    Catalysts are urgently needed to remove the residual CO in hydrogen feeds through selective oxidation for large-scale applications of hydrogen proton exchange membrane fuel cells. We herein propose a new methodology that anchors high concentration oxygen vacancies at interface by designing a CeO2-x/Cu hybrid catalyst with enhanced preferential CO oxidation activity. This hybrid catalyst, with more than 6.1% oxygen vacancies fixed at the favorable interfacial sites, displays nearly 100% CO conversion efficiency in H2-rich streams over a broad temperature window from 120 to 210 °C, strikingly 5-fold wider than that of conventional CeO2/Cu (i.e., CeO2 supported on Cu) catalyst. Moreover, the catalyst exhibits a highest cycling stability ever reported, showing no deterioration after five cycling tests, and a super long-time stability beyond 100 h in the simulated operation environment that involves CO2 and H2O. On the basis of an arsenal of characterization techniques, we clearly show that the anchored oxygen vacancies are generated as a consequence of electron donation from metal copper atoms to CeO2 acceptor and the subsequent reverse spillover of oxygen induced by electron transfer in well controlled nanoheterojunction. The anchored oxygen vacancies play a bridging role in electron capture or transfer and drive molecule oxygen into active oxygen species to interact with the CO molecules adsorbed at interfaces, thus leading to an excellent preferential CO oxidation performance. This study opens a window to design a vast number of high-performance metal-oxide hybrid catalysts via the concept of anchoring oxygen vacancies at interfaces. PMID:26444246

  9. Research on aerobics classes influence on physical prepareduess of students.

    Directory of Open Access Journals (Sweden)

    Krasulia M. А.

    2011-04-01

    Full Text Available Physical skills of female students doing aerobics have been studied. 165 female students aged 17-18 divided into three groups of 55 each have taken part in the experiment. Groups have been trained according to different methods conventionally called 'power aerobics', 'dance aerobics' and 'jump aerobics'. Level of female students' physical skills has been determined by the results of seven tests in the beginning of an academic year and after six-months term. Mathematical treatment of the results has been carried out. The most preferable as to improving physical skills level method has been discovered to be the one aimed on power abilities development method.

  10. Aerobic capacity related to cardiac size in young children

    DEFF Research Database (Denmark)

    Dencker, M; Wollmer, P; Karlsson, M;

    2013-01-01

    Aerobic capacity, defined as peak oxygen uptake (VO2PEAK), is generally considered to be the best single marker for aerobic fitness. We assessed if VO2PEAK is related to different cardiac dimensions in healthy young children on a population base.......Aerobic capacity, defined as peak oxygen uptake (VO2PEAK), is generally considered to be the best single marker for aerobic fitness. We assessed if VO2PEAK is related to different cardiac dimensions in healthy young children on a population base....

  11. Effects of aerobic training on heart rate

    Directory of Open Access Journals (Sweden)

    Marcos B. Almeida

    2003-04-01

    Full Text Available Regular physical exercise is an important factor to reduce the indexes of cardiovascular and all causes morbimortality. However, there is, apparently, additional and independent benefits of the regular practice of physical exercise and the improvement of the level of aerobic condition. Heart rate (HR is mediated primarily by the direct activity of the autonomic nervous system (ANS, specifically through the sympathetic and parasympathetic branches activities over the sinus node autorhythmicity, with predominance of the vagal activity (parasympathetic at rest, that is progressively inhibited since the onset of the exercise. The HR behavior has been widely studied during different conditions and protocols associated to the exercise. A reduction of the cardiac vagal tone (parasympathetic function and consequently a diminished HR variability in rest, independently of the protocol of measurement used, is related to an autonomic dysfunction, chronic-degenerative diseases and increased mortality risk. Individuals with high levels of aerobic condition have a lower resting HR, along with a larger parasympathetic activity or smaller sympathetic activity, but it is not necessarily a direct consequence of the exercise training, as long as other inherent adaptations to the aerobic conditioning can influence the resting HR. The HR response in the onset of the exercise represents the integrity of the vagus nerve, and the HR recovery on the post-exercise transient also denotes important prognostic information; by the way, individuals that have a slow HR recovery in the first minute post-exercise have increased mortality risk. In conclusion, the physiological mechanisms modulating HR during or after an exercise program are not totally clear, and further studies are needed.

  12. Aerobic Biostabilization of Old MSW Landfills

    Directory of Open Access Journals (Sweden)

    M. C. Zanetti

    2008-01-01

    Full Text Available Many years after the end of the cultivation phase, landfills may generate intense odours, toxic and explosive gases and heavily-polluted leachate. A wide-spreading trend in the management of MSW landfills is represented by the forced aeration of wastes in order to achieve the stabilization, reducing the negative environmental impact of uncontrolled sites (old landfills which can be definitely considered as contaminated sites and the management costs of controlled and working facilities. One of the most interesting challenges is the in situ waste aerobic stabilization, obtained by insufflating air into the wastes. The aerobic metabolism is energetically convenient in comparison with the anaerobic one, it is characterized by a higher degradation rate and a temperature increase (like in the compost production. In order to obtain an aerobic biostabilization of waste in landfills, several air injection systems have been developed and applied in the last years, like Biopuster© or AEROflott® patented systems. The feasibility of the application of in situ biostabilization must be evaluated by means of different tests, in order to evaluate the main characteristics of the wastes. The main parameters to be evaluated are the biological stability and the air permeability of the wastes. In March 2006, the biological stability of the wastes located in the Trinitapoli Landfill, Italy, has been evaluated by the Politecnico di Torino. Black Index Test and Static Respirometric Index Test have been performed in the laboratories of the Politecnico. On the basis of the obtained results, the potential biogas production from the examined landfill was estimated together with the potential volume reduction.

  13. Dancing the aerobics "Hearing loss choreography"

    OpenAIRE

    Beatriz M. Pinto; Carvalho, A.; Sérgio Oliveira

    2002-01-01

    This paper presents an overview of the health clubs acoustic problems when used for aerobics exercises classes (and similar) with loud noise levels in sound amplified music. A sample of five schools in Portugal was chosen for this survey. Noise levels in each room were measured and analyzed to calculate the standardized daily personal noise exposure levels (Leq8). Leq8 values up to 96 dB(A) were found in this type of room inducing a health risk for its occupants. This type of gymnasium is usu...

  14. [Heterotrophic Nitrification and Aerobic Denitrification of the Hypothermia Aerobic Denitrification Bacterium: Arthrobacter arilaitensis].

    Science.gov (United States)

    He, Teng-xia; Ni, Jiu-pai; Li, Zhen-lun; Sun, Quan; Ye Qing; Xu, Yi

    2016-03-15

    High concentrations of ammonium, nitrate and nitrite nitrogen were employed to clarify the abilities of heterotrophic nitrification and aerobic denitrification of Arthrobacter arilaitensis strain Y-10. Meanwhile, by means of inoculating the strain suspension into the mixed ammonium and nitrate, ammonium and nitrite nitrogen simulated wastewater, we studied the simultaneous nitrification and denitrification ability of Arthrobacter arilaitensis strain Y-10. In addition, cell optical density was assayed in each nitrogen removal process to analyze the relationship of cell growth and nitrogen removal efficiency. The results showed that the hypothermia denitrification strain Arthrobacter arilaitensis Y-10 exhibited high nitrogen removal efficiency during heterotrophic nitrification and aerobic denitrification. The ammonium, nitrate and nitrite removal rates were 65.0%, 100% and 61.2% respectively when strain Y-10 was cultivated for 4 d at 15°C with initial ammonium, nitrate and nitrite nitrogen concentrations of 208.43 mg · L⁻¹, 201.16 mg · L⁻¹ and 194.33 mg · L⁻¹ and initial pH of 7.2. Nitrite nitrogen could only be accumulated in the medium containing nitrate nitrogen during heterotrophic nitrification and aerobic denitrification process. Additionally, the ammonium nitrogen was mainly removed in the inorganic nitrogen mixed synthetic wastewater. In short, Arthrobacter arilaitensis Y-10 could conduct nitrification and denitrification effectively under aerobic condition and the ammonium nitrogen removal rate was more than 80.0% in the inorganic nitrogen mixed synthetic wastewater. PMID:27337904

  15. Aerobic/anoxic post-treatment of anaerobically digested sewage sludge as an alternative to biological nitrogen removal from reject water.

    Science.gov (United States)

    Morras, Mikel; Dosta, J; García-Heras, J L

    2015-05-01

    Stabilisation and biological nitrogen removal (BNR) of anaerobically digested sewage sludge were studied in a post-aeration reactor at pilot scale working under alternating anoxic-aerobic conditions. Digested sludge came from a two-stage anaerobic digestion (thermophilic + mesophilic). The best post-aerator performance was achieved when working at an HRT of 10 days (4 days aerobic; dissolved oxygen of 1.8 mg L(-1)) and VS content in the feed no lower than 6.7 g L(-1). Free ammonia concentration values in the effluent above 1.5 mg N L(-1) (around 150 mg NH4 (+)-N L(-1) at pH 7) were necessary to promote the BNR over nitrite. Removal efficiencies up to 80 % NH4 (+)-N, 50-55 % total nitrogen and 15-20 % VS were recorded in this study, with no external addition of chemicals. A nitrogen mass balance revealed that the high percent of NH4 (+)-N assimilated in heterotrophic growth was counteracted with that released in ammonification and fermentation, leading to a NH4 (+)-N removal mainly related to biological nitritation/denitritation. PMID:25407727

  16. Deep Conversion of Carbon Monoxide to Hydrogen and Formation of Acetate by the Anaerobic Thermophile Carboxydothermus hydrogenoformans

    NARCIS (Netherlands)

    Henstra, A.M.; Stams, A.J.M.

    2011-01-01

    Carboxydothermus hydrogenoformans is a thermophilic strictly anaerobic bacterium that catalyses the water gas shift reaction, the conversion of carbon monoxide with water to molecular hydrogen and carbon dioxide. The thermodynamically favorable growth temperature, compared to existing industrial cat

  17. Characterization and aerobic biodegradation of selected monoterpenes

    Energy Technology Data Exchange (ETDEWEB)

    Misra, G.; Pavlostathis, S.G.; Li, J.; Purdue, E.M. [Georgia Institute of Technology, Atlanta, GA (United States)

    1996-12-31

    Monoterpenes are biogenic chemicals and occur in abundance in nature. Large-scale industrial use of these chemicals has recently been initiated in an attempt to replace halogenated solvents and chlorofluorocarbons which have been implicated in the stratospheric depletion of ozone. This study examined four hydrocarbon monoterpenes (d-limonene, {alpha}-pinene, {gamma}-terpinene, and terpinolene) and four alcohols (arbanol, linalool, plinol, and {alpha}-terpineol). Water solubility, vapor pressure, and octanol/water partition coefficients were estimated. Aerobic biodegradability tests were conducted in batch reactors by utilizing forest soil extract and enriched cultures as inoculum. The hydrophobic nature and high volatility of the hydrocarbons restricted the investigation to relatively low aqueous concentrations. Each monoterpene was analyzed with a gas chromatograph equipped with a flame ionization detector after extraction from the aqueous phase with isooctane. Terpene mineralization was tested by monitoring liquid-phase carbon, CO{sub 2} production and biomass growth. All four hydrocarbons and two alcohols readily degraded under aerobic conditions. Plinol resisted degradation in assays using inocula from diverse sources, while arbanol degraded very slowly. The intrinsic biokinetics coefficients for the degradation of d-limonene and {alpha}-terpineol were estimated by using cultures enriched with the respective monoterpenes. Monoterpene biodegradation followed Monod kinetics.

  18. Constant growth rate can be supported by decreasing energy flux and increasing aerobic glycolysis

    NARCIS (Netherlands)

    Slavov, Nikolai; Budnik, Bogdan A; Schwab, David; Airoldi, Edoardo M; van Oudenaarden, Alexander

    2014-01-01

    Fermenting glucose in the presence of enough oxygen to support respiration, known as aerobic glycolysis, is believed to maximize growth rate. We observed increasing aerobic glycolysis during exponential growth, suggesting additional physiological roles for aerobic glycolysis. We investigated such ro

  19. Tryptophan Oxidative Metabolism Catalyzed by Geobacillus Stearothermophilus: A Thermophile Isolated from Kuwait Soil Contaminated with Petroleum Hydrocarbons

    OpenAIRE

    Al-Hassan, Jassim M.; Samira Al-Awadi; Sosamma Oommen; Abdulaziz Alkhamis; Mohammad Afzal

    2011-01-01

    Tryptophan metabolism has been extensively studied in humans as well as in soil. Its metabolism takes place mainly through kynurenine pathway yielding hydroxylated, deaminated and many other products of physiological significance. However, tryptophan metabolism has not been studied in an isolated thermophilic bacterium. Geobacillus stearothermophilus is a local thermophile isolated from Kuwait desert soil contaminated with petroleum hydrocarbons. The bacterium grows well at 65 °C in 0.05 M ph...

  20. Ecology of Thermophilic Fungi in Mushroom Compost, with Emphasis on Scytalidium thermophilum and Growth Stimulation of Agaricus bisporus Mycelium

    OpenAIRE

    Straatsma, Gerben; Samson, Robert A.; Olijnsma, Tineke W.; Op den Camp, Huub J. M.; Gerrits, Jan P. G.; Van Griensven, Leo J. L. D.

    1994-01-01

    Twenty-two species of thermophilic fungi were isolated from mushroom compost. Scytalidium thermophilum was present in the compost ingredients, fresh straw, horse droppings, and drainage from compost and dominated the fungal biota of compost after preparation. Of 34 species of thermophilic fungi tested, 9 promoted mycelial growth of Agaricus bisporus on sterilized compost: Chaetomium thermophilum, an unidentified Chaetomium sp., Malbranchea sulfurea, Myriococcum thermophilum, S. thermophilum, ...

  1. Differential production of slime under aerobic and anaerobic conditions.

    OpenAIRE

    Barker, L P; Simpson, W A; Christensen, G D

    1990-01-01

    A series of 37 clinical isolates of coagulase-negative staphylococci previously identified as negative for slime production by the tube test were reexamined by the tissue culture plate test under aerobic and anaerobic conditions. None of the strains produced slime under anaerobic conditions; however, five strains (13%) produced slime under aerobic conditions.

  2. Longitudinal Predictors of Aerobic Performance in Adolescent Soccer Players

    NARCIS (Netherlands)

    Valente-dos-Santos, Joao; Coelho-e-Silva, Manuel J.; Duarte, Joao; Figueiredo, Antonio J.; Liparotti, Joao R.; Sherar, Lauren B.; Elferink-Gemser, Marije T.; Malina, Robert M.

    2012-01-01

    Background. The importance of aerobic performance in youth soccer is well established. The aim of the present study was to evaluate the contributions of chronological age (CA), skeletal age (SA), body size, and training to the longitudinal development of aerobic performance in youth male soccer play

  3. Aerobic Fitness Thresholds Associated with Fifth Grade Academic Achievement

    Science.gov (United States)

    Wittberg, Richard; Cottrell, Lesley A.; Davis, Catherine L.; Northrup, Karen L.

    2010-01-01

    Background: Whereas effects of physical fitness and physical activity on cognitive function have been documented, little is known about how they are related. Purpose: This study assessed student aerobic fitness measured by FITNESSGRAM Mile times and/or Pacer circuits and whether the nature of the association between aerobic fitness and…

  4. Water Aerobics as a Form of Health Activities

    OpenAIRE

    Anna S. Batrak; Antonina V. Polyakova

    2013-01-01

    The offered literature review considers water aerobics as a form of health activities. Water aerobics is wide spread and popular, especially among women, because it is also the form of adaptive and health activities. It enlarges general physiological effect of physical exercises on the human body. Regular exercises improve physical fitness and physical development, health, mood, sleep, intensify activities and working efficiency.

  5. Aerobic Digestion. Student Manual. Biological Treatment Process Control.

    Science.gov (United States)

    Klopping, Paul H.

    This manual contains the textual material for a single-lesson unit on aerobic sludge digestion. Topic areas addressed include: (1) theory of aerobic digestion; (2) system components; (3) performance factors; (4) indicators of stable operation; and (5) operational problems and their solutions. A list of objectives, glossary of key terms, and…

  6. Thermophilic anaerobic digestion of sewage sludge: focus on the influence of the start-up. A review.

    Science.gov (United States)

    De la Rubia, M A; Riau, V; Raposo, F; Borja, R

    2013-12-01

    The thermophilic anaerobic digestion (TAD) of sewage sludge has often been found to be less stable than mesophilic treatment. In comparison to mesophilic digesters, thermophilic reactors treating sludge are generally characterized by relatively high concentrations of volatile fatty acids (VFA) in the effluent along with poor effluent quality, indicating a lower level of process stability. However, reviewing the literature related to the procedure for obtaining a thermophilic inoculum, it seems that most of the problems associated with the instability and the accumulation of organic intermediates are the result of the manner in which the thermophilic sludge has been obtained. In this paper, the different options available for obtaining an anaerobic digester operating at thermophilic temperature (55°C) have been reviewed. In this light, rapid heating to the target temperature followed by the development of thermophilic microorganisms, which can be determined by VFA dropping to ≤ 500 mg acetic acid L(-1) before increasing the organic loading rate (OLR), has been determined the most suitable means of establishing TAD.

  7. Decontamination of heavy metal laden sewage sludge with simultaneous solids reduction using thermophilic sulfur and ferrous oxidizing species.

    Science.gov (United States)

    Mehrotra, A; Kundu, K; Sreekrishnan, T R

    2016-02-01

    A possibility of using simultaneous sewage sludge digestion and metal leaching (SSDML) process at the thermophilic temperature to remove heavy metals and suspended solids from sewage sludge is explored in this study. Though thermophilic sludge digestion efficiently produces a stable sludge, its inability to remove heavy metals requires it to be used in tandem with another process like bioleaching for metal reduction. Previously, different temperature optima were known for the heterotrophs (thermophilic) responsible for the sludge digestion and the autotrophs involved in bioleaching (mesophilic), because of which the metal concentration was brought down separately in a different reactor. In our study, SSDML process was carried out at 50 °C (thermophilic) by using ferrous sulfate (batch-1) and sulfur (batch-2) as the energy source in two reactors. The concentration of volatile suspended solids reduced by >40% in both batches, while that of heavy metals zinc, copper, chromium, cadmium and nickel decreased by >50% in both batch-1 and batch-2. Lead got leached out only in batch-1. Using 16S rRNA gene-based PCR-denaturing gradient gel electrophoresis analysis, Alicyclobacillus tolerans was found to be the microorganism responsible for lowering the pH in both the reactors at thermophilic temperature. The indicator organism count was also below the maximum permissible limit making sludge suitable for agricultural use. Our results indicate that SSDML at thermophilic temperature can be effectively used for reduction of heavy metals and suspended solids from sewage sludge. PMID:26686075

  8. Decontamination of heavy metal laden sewage sludge with simultaneous solids reduction using thermophilic sulfur and ferrous oxidizing species.

    Science.gov (United States)

    Mehrotra, A; Kundu, K; Sreekrishnan, T R

    2016-02-01

    A possibility of using simultaneous sewage sludge digestion and metal leaching (SSDML) process at the thermophilic temperature to remove heavy metals and suspended solids from sewage sludge is explored in this study. Though thermophilic sludge digestion efficiently produces a stable sludge, its inability to remove heavy metals requires it to be used in tandem with another process like bioleaching for metal reduction. Previously, different temperature optima were known for the heterotrophs (thermophilic) responsible for the sludge digestion and the autotrophs involved in bioleaching (mesophilic), because of which the metal concentration was brought down separately in a different reactor. In our study, SSDML process was carried out at 50 °C (thermophilic) by using ferrous sulfate (batch-1) and sulfur (batch-2) as the energy source in two reactors. The concentration of volatile suspended solids reduced by >40% in both batches, while that of heavy metals zinc, copper, chromium, cadmium and nickel decreased by >50% in both batch-1 and batch-2. Lead got leached out only in batch-1. Using 16S rRNA gene-based PCR-denaturing gradient gel electrophoresis analysis, Alicyclobacillus tolerans was found to be the microorganism responsible for lowering the pH in both the reactors at thermophilic temperature. The indicator organism count was also below the maximum permissible limit making sludge suitable for agricultural use. Our results indicate that SSDML at thermophilic temperature can be effectively used for reduction of heavy metals and suspended solids from sewage sludge.

  9. Heart rate during aerobics classes in women with different previous experience of aerobics.

    Science.gov (United States)

    Laukkanen, R M; Kalaja, M K; Kalaja, S P; Holmala, E B; Paavolainen, L M; Tummavuori, M; Virtanen, P; Rusko, H K

    2001-01-01

    This study measured heart rate during floor and step aerobic classes at three intensity levels. A group of 20 female occasional exercisers [mean age 33 (SD 8) years, mean body mass index 21 (SD 2) kg.m-2 volunteered to participate in six aerobic classes (three floor classes, three step classes) and in a laboratory test as members of one of two groups according to their prestudy regular participation in aerobics classes. Subjects in group A had participated four or more times a week and those of group B less than twice a week. The characteristics of the groups were as follows: group A, n = 10, mean maximal oxygen uptake (VO2max) 38.7 (SD 3.6) ml.kg-1.min-1, mean maximal heart rate (HRmax) 183 (SD 8) beats.min-1; group B, n = 10, VO2max 36.1 (SD 3.6) ml.kg-1.min-1, HRmax 178 (SD 7) beats.min-1. Each class consisted of a warm-up, a 20 min period of structured aerobic exercise (cardiophase) and a cool-down. The cardiophase was planned and guided as light, (rate of perceived exertion, RPE 11-12), moderate (RPE 13-14) or heavy (RPE 15-17) by an experienced instructor. The mean heart rates during the light classes were 72 (step) and 74 (floor) %HRmax in group A and 75 (step) and 79 (floor) %HRmax in group B; during the moderate classes, 84 (step) and 80 (floor) %HRmax in group A and 82 (step) and 83 (floor) %HRmax in group B, and during the heavy classes 89 (step and floor) %HRmax in group A and 88 (step) and 92 (floor) %HRmax in group B. Differences in heart rate and %HRmax were not statistically significant between the groups. However, differences in heart rate and %HRmax between the intensities (light vs moderate, moderate vs heavy and light vs heavy) were significant within both groups (all, P < 0.01). Based on the results, we conclude that intensity management during the aerobics classes was generally successful regardless of the participants' prior participation in aerobics. However, some individuals who were older and/or had less prior participation tended to

  10. Is aerobic workload positively related to ambulatory blood pressure?

    DEFF Research Database (Denmark)

    Korshøj, Mette; Clays, Els; Lidegaard, Mark;

    2016-01-01

    PURPOSE: Cardiovascular disease is prevalent among workers with high levels of occupational physical activity. The increased risk may be due to a high relative aerobic workload, possibly leading to increased blood pressure. However, studies investigating the relation between relative aerobic...... workload and ambulatory blood pressure (ABP) are lacking. The aim was to explore the relationship between objectively measured relative aerobic workload and ABP. METHODS: A total of 116 cleaners aged 18-65 years were included after informed consent was obtained. A portable device (Spacelabs 90217...... relative aerobic workload and ABP were significant. CONCLUSIONS: Because workers may have an elevated relative aerobic workload for several hours each working day, this relationship may elucidate a mechanism behind the increased risk for cardiovascular disease among workers exposed to high levels...

  11. Aerobic rice: crop performance and water use efficiency

    Directory of Open Access Journals (Sweden)

    Chiara Grassi

    2011-11-01

    Full Text Available Rice (Oryza sativa production largely depends on traditional flooded rice systems whose sustainability is threatened by a progressive decrease in water availability and a constant increase in rice demand due to strong demographic boom in world population. A newly developed water-saving rice system is aerobic rice in which rice grows in nonflooded and unsaturated soil. From 2001, at the International Rice Research Institute in the Philippines, this system has been monitored to identify potentially promising varieties of rice able to grow as an irrigated upland crop and quantify yield potential and water use efficiency. This study reports on the results of cultivating the upland rice variety Apo under different water conditions in 2004-2005 at the IRRI farm in both the dry and wet seasons. The water treatments considered were: aerobic and flooded conditions, alternated flooded and aerobic conditions and aerobic after fallow. Yield and water productivity were compared between aerobic and flooded treatment in both seasons, with the objective of analysing the differences between water treatments. In the experiment the effect of different nitrogen (N application is also considered. The results indicate that the aerobic rice yield was lower than rice production under flood treatment, confirming that observed over past years. Nevertheless, when the aerobic condition is alternated with the anaerobic condition, or a fallow period, the production under aerobic treatment provides good yields (respectively 4.2 and 4.4 ha-1. The fallow period was introduced to observe the response of rice grown under this management. Water productivity was higher in aerobic fields, especially after fallow (0.88 g kg-1. The nitrogen application induced an increase in yield and water productivity, partially compensating for the lack of water in aerobic fields.

  12. Draft genome sequence of Herbinix hemicellulosilytica T3/55 T, a new thermophilic cellulose degrading bacterium isolated from a thermophilic biogas reactor.

    Science.gov (United States)

    Koeck, Daniela E; Maus, Irena; Wibberg, Daniel; Winkler, Anika; Zverlov, Vladimir V; Liebl, Wolfgang; Pühler, Alfred; Schwarz, Wolfgang H; Schlüter, Andreas

    2015-11-20

    A novel bacterial species was isolated from an industrial-scale biogas plant. The isolate Herbinix hemicellulosilytica T3/55(T) is able to degrade crystalline cellulose. Comparative 16S rRNA gene sequencing demonstrated that the isolate is closely related to environmental samples forming a hitherto unknown sub-cluster within the family Lachnospiraceae. The draft genome sequence of strain T3/55(T) was established and now provides the genetic basis for application of this microorganism in thermophilic degradation of lignocellulosic biomass.

  13. Thermophile-specific proteins: the gene product of aq_1292 from Aquifex aeolicus is an NTPase

    OpenAIRE

    Howe Rebecca; Roßbach Michael; Klinger Claudia; Kaufmann Michael

    2003-01-01

    Abstract Background To identify thermophile-specific proteins, we performed phylogenetic patterns searches of 66 completely sequenced microbial genomes. This analysis revealed a cluster of orthologous groups (COG1618) which contains a protein from every thermophile and no sequence from 52 out of 53 mesophilic genomes. Thus, COG1618 proteins belong to the group of thermophile-specific proteins (THEPs) and therefore we here designate COG1618 proteins as THEP1s. Since no THEP1 had been analyzed ...

  14. Selectivity of Chemisorbed Oxygen in C–H Bond Activation and CO Oxidation and Kinetic Consequences for CH₄–O₂ Catalysis on Pt and Rh Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Chin, Ya-Huei; Buda, Corneliu; Neurock, Matthew; Iglesia, Enrique

    2011-10-06

    Rate measurements, density functional theory (DFT) within the framework of transition state theory, and ensemble-averaging methods are used to probe oxygen selectivities, defined as the reaction probability ratios for O* reactions with CO and CH₄, during CH₄–O₂ catalysis on Pt and Rh clusters. CO₂ and H₂O are the predominant products, but small amounts of CO form as chemisorbed oxygen atoms (O*) are depleted from cluster surfaces. Oxygen selectivities, measured using ¹²CO–¹³CH₄–O₂ reactants, increase with O₂/ CO ratio and O* coverage and are much larger than unity at all conditions on Pt clusters. These results suggest that O* reacts much faster with CO than with CH₄, causing any CO that forms and desorbs from metal cluster surfaces to react along the reactor bed with other O* to produce CO₂ at any residence time required for detectable extents of CH₄ conversion. O* selectivities were also calculated by averaging DFTderived activation barriers for CO and CH₄ oxidation reactions over all distinct surface sites on cubo-octahedral Pt clusters (1.8 nm diameter, 201 Pt atoms) at low O* coverages, which are prevalent at low O₂ pressures during catalysis. CO oxidation involves non-activated molecular CO adsorption as the kinetically relevant step on exposed Pt atoms vicinal of chemisorbed O* atoms (on *–O* site pairs). CH₄ oxidation occurs via kinetically relevant C–H bond activation on *–* site pairs involving oxidative insertion of a Pt atom into one of the C–H bonds in CH₄, forming a three-centered HC₃–Pt–H transition state. C–H bond activation barriers reflect the strength of Pt–CH₃ and Pt–H interactions at the transition state, which correlates, in turn, with the Pt coordination and with CH₃ * binding energies. Ensemble-averaged O* selectivities increase linearly with O₂/CO ratios, which define the O* coverages, via a proportionality constant. The proportionality constant is given by the ratio of rate

  15. Aerobics trainer, health club settle discrimination lawsuit.

    Science.gov (United States)

    1995-04-01

    A health club settled out-of-court, agreeing to pay an undisclosed sum of money and to train its managers on the legal obligations of people with HIV and other disabilities, following litigation brought by an aerobics instructor at the club. The instructor filed the suit after he was forced to either disclose his HIV status to the 3,000 members or be fired. He was fired after he refused to sign a letter drafted by the club's manager. Six months later the club's president gave club employees the letter which the plaintiff argued violated his right to privacy. This is the second time a health club has settled an AIDS discrimination case. Both cases focused on the Americans with Disabilities Act (ADA). In settling the case, the club denied any wrongdoing and said they settled out of court to avoid the costs of litigation. PMID:11362274

  16. Aerobic exercises: their cardiovascular and other benefits

    International Nuclear Information System (INIS)

    Aerobic exercise can help prevent ischemic heart disease and other diseases. Physical inactivity is a major factor for developing Coronary Artery Disease (CAD) which is characterized by deposit of cholesterol, calcium and other substances in the inner lining of the arteries, that supply to cardiac muscle. It also contributes to other risk factors including obesity, hypertension, increased triglycerides, low level of HDL cholesterol and diabetes. The essential components of a systematic individualized exercise prescription include the appropriate mode, intensity, duration, frequency and progression of physical activity. There are four components of exercise program; a warm up, an endurance phase, optional recreational activity and a cool down. For sedentary individuals, exercise should start at 60% of maximum heart rare. Benefits of physical activity depend on the total amount of exercise. Vigorous leisure time activity should be promoted in order to give way to healthy living. (author)

  17. Aerobic growth at nanomolar oxygen concentrations

    DEFF Research Database (Denmark)

    Stolper, Daniel; Revsbech, Niels Peter; Canfield, Donald Eugene

    2010-01-01

    known. These capabilities also provide a framework for reconstructing a critical period in the history of life, because low, but not negligible, atmospheric oxygen levels could have persisted before the "Great Oxidation" of the Earth's surface about 2.3 to 2.4 billion years ago. Here, we show......Molecular oxygen (O2) is the second most abundant gas in the Earth's atmosphere, but in many natural environments, its concentration is reduced to low or even undetectable levels. Although low-oxygen-adapted organisms define the ecology of low-oxygen environments, their capabilities are not fully...... that Escherichia coli K-12, chosen for its well-understood biochemistry, rapid growth rate, and low-oxygen-affinity terminal oxidase, grows at oxygen levels of ≤ 3 nM, two to three orders of magnitude lower than previously observed for aerobes. Our study expands both the environmental range and temporal history...

  18. Aerobic growth at nanomolar oxygen concentrations

    DEFF Research Database (Denmark)

    Stolper, Daniel Aaron; Revsbech, Niels Peter; Canfield, Donald Eugene

    2010-01-01

    known. These capabilities also provide a framework for reconstructing a critical period in the history of life, because low, but not negligible, atmospheric oxygen levels could have persisted before the “Great Oxidation” of the Earth’s surface about 2.3 to 2.4 billion years ago. Here, we show......Molecular oxygen (O2) is the second most abundant gas in the Earth’s atmosphere, but in many natural environments, its concentration is reduced to low or even undetectable levels. Although low-oxygen-adapted organisms define the ecology of low-oxygen environments, their capabilities are not fully...... that Escherichia coli K-12, chosen for its well-understood biochemistry, rapid growth rate, and low-oxygen-affinity terminal oxidase, grows at oxygen levels of ≤ 3 nM, two to three orders of magnitude lower than previously observed for aerobes. Our study expands both the environmental range and temporal history...

  19. Ag_2~-催化CO氧化反应机理的理论研究%Theoretical Study on Mechanism of CO Oxidation Catalyzed by Ag_2~-

    Institute of Scientific and Technical Information of China (English)

    唐典勇; 胡建平; 张元勤; 胡常伟

    2009-01-01

    The mechanism of Ag_2~--catalyzed CO oxidation was investigated at the level of B3LYP theory.The computational results indicate that the absorption energy of O_2 on Ag_2~- is close tp that of O_2 on Au_2~-,while the absorption of CO on Ag_2~- is stronger than that of CO on Au_2~-,There are four reaction pathways for CO oxidation catalyzed by Ag_2~-.The most feasible pathway is the CO insertion into the Ag-O bond of Ag_2~- to produce an intermediate [Ag-AgC(O-O)O]~-,and then the intermediate [Ag-AgC(O-O)Q]~-decomposes into product CO_2 and Ag_2~-,or another CO molecule attacks [Ag-AgC(O-O)O]~- to form two C0_2 molecules and Ag_2 anion.The most difficult pathway is the di-silver carbonate intermediate pathway,which needs to overcome a total energy barrier of about 0.24 eV.Since for gold,the carbonate-like intermediate pathway requires an activation barrier of 0.61 eV,silver proves to be a better catalyst than gold.%用密度泛函理论B3LYP方法详细研究了Ag_2~-催化CO氧化反应的机理.计算结果表明,O_2分子在Ag_2~-和Au_2~-上吸附能相差不大,而CO分子在Ag_2~-上吸附要比在Au_2~-上弱得多.Ag_2~-催化CO氧化反应共有四条反应途径.最可能反应通道为CO插入Ag_2O_2~-中的Ag-O键形成中间体[Ag-AgC(O-O)O]-,然后直接分解形成产物CO_2和Ag_2O~-,或另一分子CO进攻中间体[Ag-Agc(O-O)O]-1形成两分子产物CO_2和Ag_2~-在动力学上最难进行的反应通道为经历碳酸根双银中间体,需要克服约0.24 ev的能垒.Ag_2~-催化CO氧化反应活性要高于Au_2~-.

  20. Identification and characterization of diverse xylanases from thermophilic and thermotolerant fungi

    Directory of Open Access Journals (Sweden)

    Bhat, M. K.

    2006-07-01

    Full Text Available Thirteen fungal isolates included in this study expressed multiple xylanase isoforms as observed by xylan zymograms of polyacrylamide gel electrophoresis (PAGE and isoelectrofocussing (IEF fractionated proteins. Eighty-three xylanases produced by these thermophilic and thermotolerant strains were detected using the IEF profiling technique. Xylanases identified on the basis of their isoelectric points (pI were functionally diverse and exhibited differential catalytic activities against various xylan types (birch wood xylan, larch wood xylan, oat spelt xylan, rye arabino xylan and wheat arabino xylan as well as debranched arabinan. Thermophilic isolates, Chaetomium thermophilum, Humicola insolens, Melanocarpus sp., Malbranchea sp. and Thermoascus aurantiacus, were found to produce alkaline active xylanases that showed a bleach boosting effect on Decker pulp resulting in increased brightness (1.60-2.04 ISO units.

  1. Effects of total solids content on waste activated sludge thermophilic anaerobic digestion and its sludge dewaterability.

    Science.gov (United States)

    Wang, Tianfeng; Chen, Jie; Shen, Honglang; An, Dong

    2016-10-01

    The role of total solids content on sludge thermophilic anaerobic digestion was investigated in batch reactors. A range of total solids content from 2% to 10% was evaluated with two replicates. The lowest inhibitory concentration for free ammonia and total ammonia of sludge thermophilic anaerobic digestion was 110.9-171.4mg/L and 1313.1-1806.7mg/L, respectively. The volumetric biogas production rate increased with increasing of total solids content, but the corresponding biogas yield per gram volatile solid decreased. The result of normalized capillary suction time indicated that the dewaterability of digested sludge at high total solids content was poor, while solid content of sediment obtained by centrifuging sludge at 2000g for 10min increased with increasing of total solids content of sludge. The results suggest that thickened sludge mixed with dewatered sludge at an appropriate ratio could get high organic loading rate, high biogas yield and adequate dewatering effort. PMID:26897469

  2. The Activity of Cellulase from Thermophilic Fungi Isolated from CaneBagasses

    International Nuclear Information System (INIS)

    The activity of cellulase from thermophilic fungi isolated from canebagasses has been measured. This wild strain, named fungal strain PJ-2,secreted a large amount of cellulolytic enzyme components consisting of 0.46units of avicelase, 0.8 units of carboxymethyl cellulose hydrolizing enzyme(CMCase) and 0.5 units of β-glucosidase per ml of culture broth oncultivation in Mandels Reese medium for 7 days at 500 oC. These cellulasesproduction was lower than that of Trichoderma reesei NRRL 3653 producing 0.5units/ml avicelase, 1.6 units/ml CMCase and 0.4 units/ml ofβ-glucosidase cultivated in the same medium at 30 oC. However,thermophilic fungi may be potential to be exploited in lignocellulosedegradation at the tropical areas as the process usually needs temperature ofabove 50 oC. (author)

  3. An integrated approach for genome annotation of the eukaryotic thermophile Chaetomium thermophilum.

    Science.gov (United States)

    Bock, Thomas; Chen, Wei-Hua; Ori, Alessandro; Malik, Nayab; Silva-Martin, Noella; Huerta-Cepas, Jaime; Powell, Sean T; Kastritis, Panagiotis L; Smyshlyaev, Georgy; Vonkova, Ivana; Kirkpatrick, Joanna; Doerks, Tobias; Nesme, Leo; Baßler, Jochen; Kos, Martin; Hurt, Ed; Carlomagno, Teresa; Gavin, Anne-Claude; Barabas, Orsolya; Müller, Christoph W; van Noort, Vera; Beck, Martin; Bork, Peer

    2014-12-16

    The thermophilic fungus Chaetomium thermophilum holds great promise for structural biology. To increase the efficiency of its biochemical and structural characterization and to explore its thermophilic properties beyond those of individual proteins, we obtained transcriptomics and proteomics data, and integrated them with computational annotation methods and a multitude of biochemical experiments conducted by the structural biology community. We considerably improved the genome annotation of Chaetomium thermophilum and characterized the transcripts and expression of thousands of genes. We furthermore show that the composition and structure of the expressed proteome of Chaetomium thermophilum is similar to its mesophilic relatives. Data were deposited in a publicly available repository and provide a rich source to the structural biology community. PMID:25398899

  4. Ammonia inhibition on hydrogen enriched anaerobic digestion of manure under mesophilic and thermophilic conditions

    DEFF Research Database (Denmark)

    Wang, Han; Zhang, Yifeng; Angelidaki, Irini

    2016-01-01

    Capturing of carbon dioxide by hydrogen derived from excess renewable energy (e.g., wind mills) to methane in a microbially catalyzed process offers an attractive technology for biogas production and upgrading. This bioconversion process is catalyzed by hydrogenotrophic methanogens, which are known...... to be sensitive to ammonia. In this study, the tolerance of the biogas process under supply of hydrogen, to ammonia toxicity was studied under mesophilic and thermophilic conditions. When the initial hydrogen partial pressure was 0.5 atm, the methane yield at high ammonia load (7 g NH4+-N L−1) was 41.0% and 22...... methanogens in the hydrogen enriched biogas production and upgrading processes. The highest methane production yield was achieved under 0.5 atm hydrogen partial pressure in batch reactors at all the tested ammonia levels. Furthermore, the thermophilic methanogens at 0.5 atm of hydrogen partial pressure were...

  5. Effects of Kettlebell Training on Aerobic Capacity.

    Science.gov (United States)

    Falatic, J Asher; Plato, Peggy A; Holder, Christopher; Finch, Daryl; Han, Kyungmo; Cisar, Craig J

    2015-07-01

    This study examined the effects of a kettlebell training program on aerobic capacity. Seventeen female National Collegiate Athletic Association Division I collegiate soccer players (age: 19.7 ± 1.0 years, height: 166.1 ± 6.4 cm, weight: 64.2 ± 8.2 kg) completed a graded exercise test to determine maximal oxygen consumption (V̇O2max). Participants were assigned to a kettlebell intervention group (KB) (n = 9) or a circuit weight-training (CWT) control group (n = 8). Participants in the KB group completed a kettlebell snatch test to determine individual snatch repetitions. Both groups trained 3 days a week for 4 weeks in addition to their off-season strength and conditioning program. The KB group performed the 15:15 MVO2 protocol (20 minutes of kettlebell snatching with 15 seconds of work and rest intervals). The CWT group performed multiple free-weight and dynamic body-weight exercises as part of a continuous circuit program for 20 minutes. The 15:15 MVO2 protocol significantly increased V̇O2max in the KB group. The average increase was 2.3 ml·kg⁻¹·min⁻¹, or approximately a 6% gain. There was no significant change in V̇O2max in the CWT control group. Thus, the 4-week 15:15 MVO2 kettlebell protocol, using high-intensity kettlebell snatches, significantly improved aerobic capacity in female intercollegiate soccer players and could be used as an alternative mode to maintain or improve cardiovascular conditioning. PMID:26102260

  6. A Highly Stable d-Amino Acid Oxidase of the Thermophilic Bacterium Rubrobacter xylanophilus

    OpenAIRE

    Takahashi, Shouji; Furukawara, Makoto; Omae, Keishi; Tadokoro, Namiho; Saito, Yayoi; Abe, Katsumasa; Kera, Yoshio

    2014-01-01

    d-Amino acid oxidase (DAO) is a biotechnologically attractive enzyme that can be used in a variety of applications, but its utility is limited by its relatively poor stability. A search of a bacterial genome database revealed a gene encoding a protein homologous to DAO in the thermophilic bacterium Rubrobacter xylanophilus (RxDAO). The recombinant protein expressed in Escherichia coli was a monomeric protein containing noncovalently bound flavin adenine dinucleotide as a cofactor. This protei...

  7. Regularities of polymer substances transformation into methane by thermophilic anaerobic bacteria

    OpenAIRE

    V. І. Karpenko; L. S. Yastremska; І. G. Burun; Y. V. Lembey; O. S. Tatarchenko

    2006-01-01

    The paper shows the regularities of polymer substances transformation into methane by extracted thermophilic anaerobic bacteria. The sequence of substrate use by the methane generating bacteria corresponds to the energy efficiency of the methane genesis reactions as in the first place hydrogen is used and then acetate is. Combined cultivation of extracted different anaerobic cultures gives the opportunity to increase ethanol and hydrogen yield as well as the effectiveness of methane formation.

  8. Evaluation of dairy powder products implicates thermophilic sporeformers as the primary organisms of interest.

    Science.gov (United States)

    Watterson, M J; Kent, D J; Boor, K J; Wiedmann, M; Martin, N H

    2014-01-01

    Dairy powder products (e.g., sweet whey, nonfat dry milk, acid whey, and whey protein concentrate-80) are of economic interest to the dairy industry. According to the US Dairy Export Council, customers have set strict tolerances (dairy powders; therefore, understanding proliferation and survival of sporeforming organisms within dairy powder processing plants is necessary to control and reduce sporeformer counts. Raw, work-in-process, and finished product samples were collected from 4 dairy powder processing facilities in the northeastern United States over a 1-yr period. Two separate spore treatments: (1) 80°C for 12min (to detect sporeformers) and (2) 100°C for 30min (to detect highly heat resistant sporeformers) were applied to samples before microbiological analyses. Raw material, work-in-process, and finished product samples were analyzed for thermophilic, mesophilic, and psychrotolerant sporeformers, with 77.5, 71.0, and 4.6% of samples being positive for those organisms, respectively. Work-in-process and finished product samples were also analyzed for highly heat resistant thermophilic and mesophilic sporeformers, with 63.7 and 42.6% of samples being positive, respectively. Sporeformer prevalence and counts varied considerably by product and plant; sweet whey and nonfat dry milk showed a higher prevalence of thermophilic and mesophilic sporeformers compared with acid whey and whey protein concentrate-80. Unlike previous reports, we found limited evidence for increased spore counts toward the end of processing runs. Our data provide important insight into spore contamination patterns associated with production of different types of dairy powders and support that thermophilic sporeformers are the primary organism of concern in dairy powders.

  9. Thermophile-specific proteins: the gene product of aq_1292 from Aquifex aeolicus is an NTPase

    Directory of Open Access Journals (Sweden)

    Howe Rebecca

    2003-09-01

    Full Text Available Abstract Background To identify thermophile-specific proteins, we performed phylogenetic patterns searches of 66 completely sequenced microbial genomes. This analysis revealed a cluster of orthologous groups (COG1618 which contains a protein from every thermophile and no sequence from 52 out of 53 mesophilic genomes. Thus, COG1618 proteins belong to the group of thermophile-specific proteins (THEPs and therefore we here designate COG1618 proteins as THEP1s. Since no THEP1 had been analyzed biochemically thus far, we characterized the gene product of aq_1292 which is THEP1 from the hyperthermophilic bacterium Aquifex aeolicus (aaTHEP1. Results aaTHEP1 was cloned in E. coli, expressed and purified to homogeneity. At a temperature optimum between 70 and 80°C, aaTHEP1 shows enzymatic activity in hydrolyzing ATP to ADP + Pi with kcat = 5 × 10-3 s-1 and Km = 5.5 × 10-6 M. In addition, the enzyme exhibits GTPase activity (kcat = 9 × 10-3 s-1 and Km= 45 × 10-6 M. aaTHEP1 is inhibited competitively by CTP, UTP, dATP, dGTP, dCTP, and dTTP. As shown by gel filtration, aaTHEP1 in its purified state appears as a monomer. The enzyme is resistant to limited proteolysis suggesting that it consists of a single domain. Although THEP1s are annotated as "predicted nucleotide kinases" we could not confirm such an activity experimentally. Conclusion Since aaTHEP1 is the first member of COG1618 that is characterized biochemically and functional information about one member of a COG may be transferred to the entire COG, we conclude that COG1618 proteins are a family of thermophilic NTPases.

  10. Engineering pyruvate decarboxylase-mediated ethanol production in the thermophilic host Geobacillus thermoglucosidasius.

    Science.gov (United States)

    Van Zyl, L J; Taylor, M P; Eley, K; Tuffin, M; Cowan, D A

    2014-02-01

    This study reports the expression, purification, and kinetic characterization of a pyruvate decarboxylase (PDC) from Gluconobacter oxydans. Kinetic analyses showed the enzyme to have high affinity for pyruvate (120 μM at pH 5), high catalytic efficiency (4.75 × 10(5) M(-1) s(-1) at pH 5), a pHopt of approximately 4.5 and an in vitro temperature optimum at approximately 55 °C. Due to in vitro thermostablity (approximately 40 % enzyme activity retained after 30 min at 65 °C), this PDC was considered to be a suitable candidate for heterologous expression in the thermophile Geobacillus thermoglucosidasius for ethanol production. Initial studies using a variety of methods failed to detect activity at any growth temperature (45-55 °C). However, the application of codon harmonization (i.e., mimicry of the heterogeneous host's transcription and translational rhythm) yielded a protein that was fully functional in the thermophilic strain at 45 °C (as determined by enzyme activity, Western blot, mRNA detection, and ethanol productivity). Here, we describe the first successful expression of PDC in a true thermophile. Yields as high as 0.35 ± 0.04 g/g ethanol per gram of glucose consumed were detected, highly competitive to those reported in ethanologenic thermophilic mutants. Although activities could not be detected at temperatures approaching the growth optimum for the strain, this study highlights the possibility that previously unsuccessful expression of pdcs in Geobacillus spp. may be the result of ineffective transcription/translation coupling.

  11. Survey of thermophilic Campylobacter species in cats and dogs in north-western Nigeria

    OpenAIRE

    Adewale Kolawale; Junaidu U. Abdulkadir; Abdullahi A. Magaji; Mohammed D. Salihu

    2010-01-01

    This study was conducted in north-western Nigeria to investigate the role of cats and dogs as potential reservoirs of thermophilic Campylobacter species. Faecal samples were analysed from 104 cats and 141 dogs between March 2007 and March 2009. The samples were collected from animals in households, those presented to veterinary premises and feline colonies. Campylobacter spp. were isolated from 39 (27.7%) and 19 (18.3%) dogs and cats, respectively. There was no significant difference in isola...

  12. A constant flux of diverse thermophilic bacteria into the cold arctic seabed

    DEFF Research Database (Denmark)

    Hubert, Casey; Loy, Alexander; Nickel, Maren;

    2009-01-01

    Microorganisms have been repeatedly discovered in environments that do not support their metabolic activity. Identifying and quantifying these misplaced organisms can reveal dispersal mechanisms that shape natural microbial diversity. Using endospore germination experiments, we estimated a stable...... supply of thermophilic bacteria into permanently cold Arctic marine sediment at a rate exceeding 108 spores per square meter per year. These metabolically and phylogenetically diverse Firmicutes show no detectable activity at cold in situ temperatures but rapidly mineralize organic matter by hydrolysis...

  13. A study of the oxygen and carbon dioxide requirements of thermophilic campylobacters.

    OpenAIRE

    Bolton, F J; Coates, D.

    1983-01-01

    The oxygen and carbon dioxide requirements of different biotypes of thermophilic campylobacters were investigated by means of (a) quantitative studies, and (b) total growth studies. Oxygen tolerance of the five test organisms differed markedly and varied with the carbon dioxide concentration. At most carbon dioxide concentrations tested, Campylobacter jejuni strains NCTC 11168 and NCTC 11392 tolerated 21% oxygen (growth reduced), C coli NCTC 11353 tolerated 15% oxygen (growth reduced), and C ...

  14. Growth-promoting effect of thermophilic fungi on the mycelium of the edible mushroom Agaricus bisporus.

    OpenAIRE

    Wiegant, W.M.; Wery, J.; E. T. Buitenhuis; de Bont, J A

    1992-01-01

    The growth-promoting effect of the thermophilic fungus Scytalidium thermophilum in mushroom compost on the mycelium of the edible mushroom Agaricus bisporus was investigated. Results obtained by others were confirmed by showing that S. thermophilum leads to an increased hyphal extension rate of the mushroom mycelium. However, it was demonstrated that hyphal extension rates were not clearly related to mushroom biomass increase rates. A number of experiments pointed strongly towards CO2 as the ...

  15. Comparing mesophilic and thermophilic anaerobic digestion of chicken manure: Microbial community dynamics and process resilience

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Qigui; Takemura, Yasuyuki; Kubota, Kengo [Department of Civil and Environmental Engineering, Graduate School of Engineering Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Li, Yu-You, E-mail: yyli@epl1.civil.tohoku.ac.jp [Department of Civil and Environmental Engineering, Graduate School of Engineering Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi’an University of Architecture and Technology, Xi’an (China)

    2015-09-15

    Highlights: • Microbial community dynamics and process functional resilience were investigated. • The threshold of TAN in mesophilic reactor was higher than the thermophilic reactor. • The recoverable archaeal community dynamic sustained the process resilience. • Methanosarcina was more sensitive than Methanoculleus on ammonia inhibition. • TAN and FA effects the dynamic of hydrolytic and acidogenic bacteria obviously. - Abstract: While methane fermentation is considered as the most successful bioenergy treatment for chicken manure, the relationship between operational performance and the dynamic transition of archaeal and bacterial communities remains poorly understood. Two continuous stirred-tank reactors were investigated under thermophilic and mesophilic conditions feeding with 10%TS. The tolerance of thermophilic reactor on total ammonia nitrogen (TAN) was found to be 8000 mg/L with free ammonia (FA) 2000 mg/L compared to 16,000 mg/L (FA1500 mg/L) of mesophilic reactor. Biomethane production was 0.29 L/gV S{sub in} in the steady stage and decreased following TAN increase. After serious inhibition, the mesophilic reactor was recovered successfully by dilution and washing stratagem compared to the unrecoverable of thermophilic reactor. The relationship between the microbial community structure, the bioreactor performance and inhibitors such as TAN, FA, and volatile fatty acid was evaluated by canonical correspondence analysis. The performance of methanogenic activity and substrate removal efficiency were changed significantly correlating with the community evenness and phylogenetic structure. The resilient archaeal community was found even after serious inhibition in both reactors. Obvious dynamics of bacterial communities were observed in acidogenic and hydrolytic functional bacteria following TAN variation in the different stages.

  16. Biohydrogen Production by the Thermophilic Bacterium Caldicellulosiruptor saccharolyticus: Current Status and Perspectives

    OpenAIRE

    Kengen, Servé W. M.; Verhaart, Marcel R. A.; John van der Oost; Abraham A. M. Bielen

    2013-01-01

    Caldicellulosiruptor saccharolyticus is one of the most thermophilic cellulolytic organisms known to date. This Gram-positive anaerobic bacterium ferments a broad spectrum of mono-, di- and polysaccharides to mainly acetate, CO2 and hydrogen. With hydrogen yields approaching the theoretical limit for dark fermentation of 4 mol hydrogen per mol hexose, this organism has proven itself to be an excellent candidate for biological hydrogen production. This review provides an overview of the resear...

  17. Production, purification and characterization of xylanase using alkalo-thermophilic Bacillus halodurans KR-1

    OpenAIRE

    Krityanand Kumar Mahatman; Neha Garg; Ranjeeta Chauhan; Anil Kumar

    2010-01-01

    Xylanase (EC. 3.2.1.8) has been isolated from an alkalo-thermophilic bacteria, Bacillus halodurans strain KR-1 isolated from the soil near river bed at Indore. The bacteria secreted xylanase in the growth medium in the presence of xylan. The production of the enzyme was induced in the presence of glucose, mannose, lactose and maltose whereas presence of starch, cellulose and sucrose retarded in enzyme production. The presence of casein, peptone, sodium nitrate and potassium nitrate as nitroge...

  18. Autohydrolysis of plant xylans by apoplastic expression of thermophilic bacterial endo-xylanases

    DEFF Research Database (Denmark)

    Borkhardt, Bernhard; Harholt, Jesper; Ulvskov, Peter Bjarne;

    2010-01-01

    The genes encoding the two endo-xylanases XynA and XynB from the thermophilic bacterium Dictyoglomus thermophilum were codon optimized for expression in plants. Both xylanases were designed to be constitutively expressed under the control of the CaMV 35S promoter and targeted to the apoplast. Tra...... treatment of wildtype and transgenic extracts from dry stems showed a decrease in the molecular weight of xylans from transgenic stems....

  19. Bioleaching of electronic scrap by mixed culture of moderately thermophilic microorganisms

    OpenAIRE

    Ivănuş D.; Ivănuş R.C.; Călmuc F.

    2010-01-01

    A process for the metal recovery from electronic scrap using bacterial leaching was investigated. A mixed culture of moderately thermophilic microorganisms was enriched from acid mine drainages (AMDs) samples collected from several sulphide mines in Romania, and the bioleaching of electronic scrap was conducted both in shake flask and bioreactor. The results show that in the shake flask, the mixture can tolerate 50 g/L scrap after being acclimated to gradually increased concentrations o...

  20. Optimization of key factors affecting hydrogen production from sugarcane bagasse by a thermophilic anaerobic pure culture

    OpenAIRE

    Lai, Zhicheng; Zhu, Muzi; Yang, Xiaofeng; Wang, JuFang; Li, Shuang

    2014-01-01

    Background Hydrogen is regarded as an attractive future energy carrier for its high energy content and zero CO2 emission. Currently, the majority of hydrogen is generated from fossil fuels. However, from an environmental perspective, sustainable hydrogen production from low-cost lignocellulosic biomass should be considered. Thermophilic hydrogen production is attractive, since it can potentially convert a variety of biomass-based substrates into hydrogen at high yields. Results Sugarcane baga...

  1. Physiological characteristics of the extreme thermophile Caldicellulosiruptor saccharolyticus: an efficient hydrogen cell factory

    OpenAIRE

    Zeidan Ahmad A; Willquist Karin; van Niel Ed WJ

    2010-01-01

    Abstract Global concerns about climate changes and their association with the use of fossil fuels have accelerated research on biological fuel production. Biological hydrogen production from hemicellulose-containing waste is considered one of the promising avenues. A major economical issue for such a process, however, is the low substrate conversion efficiency. Interestingly, the extreme thermophilic bacterium Caldicellulosiruptor saccharolyticus can produce hydrogen from carbohydrate-rich su...

  2. Comparing mesophilic and thermophilic anaerobic digestion of chicken manure: Microbial community dynamics and process resilience

    International Nuclear Information System (INIS)

    Highlights: • Microbial community dynamics and process functional resilience were investigated. • The threshold of TAN in mesophilic reactor was higher than the thermophilic reactor. • The recoverable archaeal community dynamic sustained the process resilience. • Methanosarcina was more sensitive than Methanoculleus on ammonia inhibition. • TAN and FA effects the dynamic of hydrolytic and acidogenic bacteria obviously. - Abstract: While methane fermentation is considered as the most successful bioenergy treatment for chicken manure, the relationship between operational performance and the dynamic transition of archaeal and bacterial communities remains poorly understood. Two continuous stirred-tank reactors were investigated under thermophilic and mesophilic conditions feeding with 10%TS. The tolerance of thermophilic reactor on total ammonia nitrogen (TAN) was found to be 8000 mg/L with free ammonia (FA) 2000 mg/L compared to 16,000 mg/L (FA1500 mg/L) of mesophilic reactor. Biomethane production was 0.29 L/gV Sin in the steady stage and decreased following TAN increase. After serious inhibition, the mesophilic reactor was recovered successfully by dilution and washing stratagem compared to the unrecoverable of thermophilic reactor. The relationship between the microbial community structure, the bioreactor performance and inhibitors such as TAN, FA, and volatile fatty acid was evaluated by canonical correspondence analysis. The performance of methanogenic activity and substrate removal efficiency were changed significantly correlating with the community evenness and phylogenetic structure. The resilient archaeal community was found even after serious inhibition in both reactors. Obvious dynamics of bacterial communities were observed in acidogenic and hydrolytic functional bacteria following TAN variation in the different stages

  3. Trends in occurrence of thermophilous dragonfly species in North Rhine-Westphalia (NRW

    Directory of Open Access Journals (Sweden)

    Klaus-Jürgen Conze

    2010-12-01

    Full Text Available Since 1996 the “Workgroup Odonata in North Rhine-Westphalia” (“AK Libellen NRW” has built up a data base including about 150.000 data sets concerning the occurrence of dragonflies in North Rhine-Westphalia (NRW. This data confirms an increase and spread of some thermophilous dragonfly species in NRW, and the effects of climate change evidenced by an increasing average temperature, are considered to be important reasons for this process.

  4. High stability of apo-cytochrome c' from thermophilic Hydrogenophilus thermoluteolus.

    Science.gov (United States)

    Fujii, Sotaro; Masanari, Misa; Yamanaka, Masaru; Wakai, Satoshi; Sambongi, Yoshihiro

    2014-01-01

    Apo-cytochomes c without heme are usually unstructured. Here we showed that apo-form of thermophilic Hydrogenophilus thermoluteolus cytochrome c' (PHCP) was a monomeric protein with high helix content. Apo-PHCP was thermally stable, possibly due to the hydrophobic residues and ion pairs. PHCP is the first example of a structured apo-cytochrome c', which will expand our view of hemoprotein structure formation.

  5. Upflow anaerobic solid-state (UASS) digestion of horse manure: Thermophilic vs. mesophilic performance.

    Science.gov (United States)

    Böske, Janina; Wirth, Benjamin; Garlipp, Felix; Mumme, Jan; Van den Weghe, Herman

    2015-01-01

    Energetic use of complex lignocellulosic wastes has gained global interest. Thermophilic digestion of horse manure based on straw was investigated using the upflow anaerobic solid-state (UASS) process. Increasing the organic loading rate from 2.5 to 5.5gvsL(-)(1)d(-)(1) enhanced the average methane production rate from 0.387 to 0.687LCH4L(-)(1)d(-)(1), whereas the yield decreased from 154.8 to 124.8LCH4kgvs(-)(1). A single-stage and two-stage process design showed almost the same performance. Compared to prior experiments at mesophilic conditions, thermophilic conditions showed a significantly higher efficiency with an increase of 59.8% in methane yield and 58.1% in methane production rate. Additional biochemical methane potential (BMP) tests with two types of horse manure and four different bedding materials showed that wheat straw obtained the highest BMP. The results show that the thermophilic UASS process can be the key to an efficient energy recovery from straw-based manures.

  6. Genetics of thermophilic bacteria: Progress report, May 1, 1986--June 30, 1988

    Energy Technology Data Exchange (ETDEWEB)

    Welker, N.E.

    1988-01-01

    Efficient and reliable protoplasting, regeneration and fusion techniques have been established for a prototrophic strain of Bacillus stearothermophilus. A variety of auxotrophic mutants and a restriction-deficient mutant were isolated and protoplast fusion was used to construct isogenic strains and for chromosomal mapping. Two linkage groups (hom thr and his gly pur-1) were established using this system. The order of the markers is similar to analagous markers on the Bacillus subtilis chromosome. We have evidence that this genetic exchange system can be used for linear chromosomal DNA transformation of protoplasts. Investigations have recently been initiated to develop a transducing system in this strain. Attempts to introduce a thermophile plasmid into strain NUB36 by transformation of protoplasts or protoplast fusion were unsuccessful. We think that the lack of success encountered in these studies is because this plasmid is not stably maintained at high temperature and/or is incompatible with the cryptic plasmids contained in this strain. This is the first report of a reliable genetic exchange system in B. stearothermophilus. This system can be used for the genetic analysis of this organism and for molecular cloning. The development of a host-vector system for cloning in B. stearothermophilus will make it possible to clone genes encoding cellulose hydrolysis, alcohol formation, or methane production. In addition, information gained from the genetic analysis of thermophilic bacilli may be of value in developing genetic systems in thermophilic eubacteria and archaebacteria. 3 tabs.

  7. Comparing mesophilic and thermophilic anaerobic digestion of chicken manure: Microbial community dynamics and process resilience.

    Science.gov (United States)

    Niu, Qigui; Takemura, Yasuyuki; Kubota, Kengo; Li, Yu-You

    2015-09-01

    While methane fermentation is considered as the most successful bioenergy treatment for chicken manure, the relationship between operational performance and the dynamic transition of archaeal and bacterial communities remains poorly understood. Two continuous stirred-tank reactors were investigated under thermophilic and mesophilic conditions feeding with 10%TS. The tolerance of thermophilic reactor on total ammonia nitrogen (TAN) was found to be 8000mg/L with free ammonia (FA) 2000mg/L compared to 16,000mg/L (FA1500mg/L) of mesophilic reactor. Biomethane production was 0.29 L/gVSin in the steady stage and decreased following TAN increase. After serious inhibition, the mesophilic reactor was recovered successfully by dilution and washing stratagem compared to the unrecoverable of thermophilic reactor. The relationship between the microbial community structure, the bioreactor performance and inhibitors such as TAN, FA, and volatile fatty acid was evaluated by canonical correspondence analysis. The performance of methanogenic activity and substrate removal efficiency were changed significantly correlating with the community evenness and phylogenetic structure. The resilient archaeal community was found even after serious inhibition in both reactors. Obvious dynamics of bacterial communities were observed in acidogenic and hydrolytic functional bacteria following TAN variation in the different stages. PMID:26054964

  8. Enhancing ethanol production from thermophilic and mesophilic solid digestate using ozone combined with aqueous ammonia pretreatment.

    Science.gov (United States)

    Wang, Dianlong; Xi, Jiang; Ai, Ping; Yu, Liang; Zhai, Hong; Yan, Shuiping; Zhang, Yanlin

    2016-05-01

    Pretreatment with ozone combined with aqueous ammonia was used to recover residual organic carbon from recalcitrant solid digestate for ethanol production after anaerobic digestion (AD) of rice straw. Methane yield of AD at mesophilic and thermophilic conditions, and ethanol production of solid digestate were investigated. The results showed that the methane yield at thermophilic temperature was 72.2% higher than that at mesophilic temperature under the same conditions of 24days and 17% solid concentration. And also the ethanol production efficiency of solid digestate after thermophilic process was 24.3% higher than that of solid digestate after mesophilic process. In this study, the optimal conditions for integrated methane and ethanol processes were determined as 55°C, 17% solid concentration and 24days. 58.6% of glucose conversion, 142.8g/kg of methane yield and 65.2g/kg of ethanol yield were achieved, and the highest net energy balance was calculated as 6416kJ/kg.

  9. Mineralization of a Proterozoic Sulfide Black Smoker Chimney and Thermophilous Microorganisms in Eastern Hebei, China

    Institute of Scientific and Technical Information of China (English)

    XIA Xuehui; LIAN Wei; YUAN Congjian; YAN Fei; YUAN Jiazhong

    2008-01-01

    A sulfide black smoker chimney exists in the Gaobanhe seabed exhalation massive sulfidedeposit in the Xinglong-Kuancheng secondary fault basin of the Proterozoic Yanliao rift trough inHebei Province, taking the shape of mounds, individually about 2-3 cm high. Abundant fossils ofthermophilous bacteria and algae in perfect preservation are found in the ore surrounding the blacksmoker chimney. Scanning electron microscopy (SEM) and molecular biomarker studies on themicroorganismal ore fabric show that the microorganism in the sulfide ore is in fact a sedimentaryproduct of probiotic bacteria and algae. In the special food chain based on black smoker chimney atancient seabed- thermophilous bacteria, the thermophilons bacteria and algae reproduce in largequantity. Intermittently erupting of fluid from the chimney creats conditions for formation of sulfidedeposit. In the process of exhalation action of hot fluid, thermophilous bacteria and algae grow andreproduce around the sulfide black smoker chimney, absorbing mineralizing substances brought bythe fluid. Massive sulfide deposits are formed in this process of absorption of seabed black smokerchimney exhalation-mineralizing fluid puisation.thermophilous microorganism.

  10. Investigating the potential of thermophilic species for ethanol production from industrial spent sulfite liquor

    Directory of Open Access Journals (Sweden)

    Michaela Weissgram

    2015-10-01

    Full Text Available Thermophilic microorganisms hold a great potential for bioethanol production on waste biomass, due to their ability to utilize pentoses and hexoses alike. However, to date hardly any data on thermophiles growing directly on industrial substrates like spent sulfite liquor (SSL are available. This contribution investigates the ability of Thermoanaerobacter species to utilize the main sugars in the used SSL (mannose, glucose and xylose and the effect of process parameters (pH, temperature and sugar concentration on their growth. Based on these results the strain T. mathranii was chosen for further studies. The ability of T. mathranii to grow directly on SSL was investigated and the effect of several inhibiting substances on growth was elucidated. Furthermore it was tested whether pretreatment with activated charcoal can increase the fermentability of SSL. The fermentations were evaluated based on yields and specific rates. It could be shown that T. mathranii was able to ferment all sugars in the investigated softwood SSL and fermented diluted, untreated SSL (up to 2.7% (w/w dry matter. Pretreatment with activated charcoal could slightly reduce the amount of phenols in the substrate and thus facilitate growth and ethanol production on higher SSL concentrations (up to 4.7% (w/v dry matter. Ethanol yields of 0.29-0.44 Cmmol of ethanol per Cmmol sugar were obtained on untreated and pretreated spent sulfite liquor, respectively. These results on an industrial substrate strengthen the claim that thermophilic microorganisms might be the optimal candidates for forest biorefinery.

  11. Comparative microbiological-hygienic studies in mesophilic and thermophilic fouling of sewage sludge

    Energy Technology Data Exchange (ETDEWEB)

    Pohlig-Schmitt, M.; Philipp, W.; Wekerle, J.; Strauch, D.

    Investigations concerning the inactivation of microbial pathogens (bacteria, viruses and parasites) during anaerobic, alkaline dignestion of sludge are described. A thermophilic (54/sup 0/C) and a mesophilic (34/sup 0/C) operated biogas model plant were compared from the point of view of hygiene. Is was found that in the thermophilic process Salmonella senftenberg survived 13,5 h, Streptococcus faecium 55 h, Streptococcus faecalis 42 h and Klebsiella pneumoniae 0,5 h. Within 30 min eggs of Ascaris suum lost their infectivity Bovine Parvovirus was inactivated after 1 d to 2 d treatment. Survival times under mesophilic conditions of 13 d for Salmonella senftenberg and more than 8 mouth for Streptococcus faecium were found. Poliovirus Type 1 was inactivated in 8 d while Bovine Parvovirus survived no longer than 15 d. The results obtained in the thermophilic process were compared to those after heat treatment of the test microorganisms in ampules exposed in a wather-bath under defined conditions to 54/sup 0/C. It was found, that the bacteria survived only about half the time in this case. Poliovirus Type 1 was inactivated after 0,75 h and Bovine Parvovirus after 7 d exposure. (orig.RB)

  12. Characterization of a novel non-specific nuclease from thermophilic bacteriophage GBSV1

    Directory of Open Access Journals (Sweden)

    Zhang Xiaobo

    2008-04-01

    Full Text Available Abstract Background Thermostable enzymes from thermophiles have attracted extensive studies. In this investigation, a nuclease-encoding gene (designated as GBSV1-NSN was obtained from a thermophilic bacteriophage GBSV1 for the first time. Results After recombinant expression in Escherichia coli, the purified GBSV1-NSN exhibited non-specific nuclease activity, being able to degrade various nucleic acids, including RNA, single-stranded DNA and double-stranded DNA that was circular or linear. Based on sequence analysis, the nuclease shared no homology with any known nucleases, suggesting that it was a novel nuclease. The characterization of the recombinant GBSV1-NSN showed that its optimal temperature and pH were 60°C and 7.5, respectively. The results indicated that the enzymatic activity was inhibited by enzyme inhibitors or detergents, such as ethylene diamine tetraacetic acid, citrate, dithiothreitol, β-mercaptoethanol, guanidine hydrochloride, urea and SDS. In contrast, the nuclease activity was enhanced by TritonX-100, Tween-20 or chaps to approximately 124.5% – 141.6%. The Km of GBSV1-NSN nuclease was 231, 61 and 92 μM, while its kcat was 1278, 241 and 300 s-1 for the cleavage of dsDNA, ssDNA and RNA, respectively. Conclusion Our study, therefore, presented a novel thermostable non-specific nuclease from thermophilic bacteriophage and its overexpression and purification for scientific research and applications.

  13. Innovative two-stage mesophilic/thermophilic anaerobic degradation of sonicated sludge: performances and energy balance.

    Science.gov (United States)

    Gianico, A; Braguglia, C M; Gallipoli, A; Mininni, G

    2015-05-01

    This study investigates for the first time, on laboratory scale, the possible application of an innovative enhanced stabilization process based on sequential mesophilic/thermophilic anaerobic digestion of waste-activated sludge, with low-energy sonication pretreatment. The first mesophilic digestion step was conducted at short hydraulic retention time (3-5 days), in order to favor volatile fatty acid production, followed by a longer thermophilic step of 10 days to enhance the bioconversion kinetics, assuring a complete pathogen removal. The high volatile solid removals, up to 55%, noticeably higher compared to the performances of a single-stage process carried out in same conditions, can guarantee the stability of the final digestate for land application. The ultrasonic pretreatment influenced significantly the fatty acid formation and composition during the first mesophilic step, improving consequently the thermophilic conversion of these compounds into methane. Methane yield from sonicated sludge digestion reached values up to 0.2 Nm(3)/kgVSfed. Positive energy balances highlighted the possible exploitation of this innovative two-stage digestion in place of conventional single-stage processes. PMID:24906832

  14. Study of thermophilic anaerobic cleaning systems; Studier av termofila anaeroba reningssystem

    Energy Technology Data Exchange (ETDEWEB)

    Boman, B.; Davisson, G.

    1994-11-01

    The aim of this study was to indicate how mesophile and thermophilic anaerobic systems differ in their capacity to degrade persistent organic compounds. The experiments were carried out in semi-batch lab.scale reactors working at 35, 55 and 70 degrees C and were evaluated by recording pH, COD, TSS, redox potential, fatty acids, gas production, methane concentration and the concentration of specific organic compounds. Totally, seven different reactors and four different specific organic compounds were used in this study. The microbial activity within the semi-batch reactors showed a pronounced tendency to oscillate in an irregular and unpredictable way. This behaviour stressed the difficulties in running the decided experiments. These experiences are unfortunately confirmed by many other investigators within the present field. The results do not indicate differences between mesophile and thermophilic anaerobic reactors in terms of `not degradable-degradable` but only as differences in degree of degradation rates. 6-chlorovanillin and 3,5-dinitrobenzoic acid showed increasing degradation rate in the thermophilic range while no differences could be detected for 4,5-dichloroguaiacol. In the case of {beta}-sitosterol the mesophile reference reactor crash. 14 refs, 6 figs, 3 tabs

  15. Upflow anaerobic solid-state (UASS) digestion of horse manure: Thermophilic vs. mesophilic performance.

    Science.gov (United States)

    Böske, Janina; Wirth, Benjamin; Garlipp, Felix; Mumme, Jan; Van den Weghe, Herman

    2015-01-01

    Energetic use of complex lignocellulosic wastes has gained global interest. Thermophilic digestion of horse manure based on straw was investigated using the upflow anaerobic solid-state (UASS) process. Increasing the organic loading rate from 2.5 to 5.5gvsL(-)(1)d(-)(1) enhanced the average methane production rate from 0.387 to 0.687LCH4L(-)(1)d(-)(1), whereas the yield decreased from 154.8 to 124.8LCH4kgvs(-)(1). A single-stage and two-stage process design showed almost the same performance. Compared to prior experiments at mesophilic conditions, thermophilic conditions showed a significantly higher efficiency with an increase of 59.8% in methane yield and 58.1% in methane production rate. Additional biochemical methane potential (BMP) tests with two types of horse manure and four different bedding materials showed that wheat straw obtained the highest BMP. The results show that the thermophilic UASS process can be the key to an efficient energy recovery from straw-based manures. PMID:25459798

  16. A Numerical Evaluation on the Viability of Heap Thermophilic Bioleaching of Chalcopyrite

    Science.gov (United States)

    Vilcaez, J.; Suto, K.; Inoue, C.

    2007-03-01

    The present numerical evaluation explores into the interactions among the many variables governing the mass and heat transport processes that take place in a heap thermophilic bioleaching system. The necessity of using mesophiles together with thermophiles is proved by tracing the activity of both microorganisms individually at each point throughout the heap. The role of key variables such as the fraction of FeS2 per CuFeS2 leached was quantified and its importance highlighted. In this evaluation, the heat transfer process plays the main role because of the heat accumulation required to maintain the heap temperature within the range of 60 °C to 80 °C where thermophilic microorganisms are capable of completing the unfinished dissolution of copper started by mesophilic microorganisms at 30 °C. The evaluation was done taking into consideration: biological activity as function of the temperature in the heap, heat loss due to conduction and advection from the top and bottom of the heap, and mass transfer between the gas and liquid phases as a function of temperature. The exothermic nature of the leaching reactions of CuFeS2 and FeS2 makes the system auto-thermal.

  17. Enhancing ethanol production from thermophilic and mesophilic solid digestate using ozone combined with aqueous ammonia pretreatment.

    Science.gov (United States)

    Wang, Dianlong; Xi, Jiang; Ai, Ping; Yu, Liang; Zhai, Hong; Yan, Shuiping; Zhang, Yanlin

    2016-05-01

    Pretreatment with ozone combined with aqueous ammonia was used to recover residual organic carbon from recalcitrant solid digestate for ethanol production after anaerobic digestion (AD) of rice straw. Methane yield of AD at mesophilic and thermophilic conditions, and ethanol production of solid digestate were investigated. The results showed that the methane yield at thermophilic temperature was 72.2% higher than that at mesophilic temperature under the same conditions of 24days and 17% solid concentration. And also the ethanol production efficiency of solid digestate after thermophilic process was 24.3% higher than that of solid digestate after mesophilic process. In this study, the optimal conditions for integrated methane and ethanol processes were determined as 55°C, 17% solid concentration and 24days. 58.6% of glucose conversion, 142.8g/kg of methane yield and 65.2g/kg of ethanol yield were achieved, and the highest net energy balance was calculated as 6416kJ/kg. PMID:26868156

  18. Potential use of thermophilic dark fermentation effluents in photofermentative hydrogen production by Rhodobacter capsulatus

    Energy Technology Data Exchange (ETDEWEB)

    Ozgura, E.; Afsar, N.; Eroglu, I. [Middle East Technical University, Department of Chemical Engineering, 06531 Ankara (Turkey); De Vrije, T.; Claassen, P.A.M. [Wageningen UR, Agrotechnology and Food Sciences Group, Wageningen UR, P.O. Box 17, 6700 AA Wageningen (Netherlands); Yucel, M.; Gunduz, U. [Middle East Technical University, Department of Biology, 06531 Ankara (Turkey)

    2010-12-15

    Biological hydrogen production by a sequential operation of dark and photofermentation is a promising route to produce hydrogen. The possibility of using renewable resources, like biomass and agro-industrial wastes, provides a dual effect of sustainability in biohydrogen production and simultaneous waste removal. In this study, photofermentative hydrogen production on effluents of thermophilic dark fermentations on glucose, potato steam peels (PSP) hydrolysate and molasses was investigated in indoor, batch operated bioreactors. An extreme thermophile Caldicellulosiruptor saccharolyticus was used in the dark fermentation step, and Rhodobacter capsulatus (DSM1710) was used in the photofermentation step. Addition of buffer, Fe and Mo to dark fermentor effluents (DFEs) improved the overall efficiency of hydrogen production. The initial acetate concentration in the DFE needed to be adjusted to 30-40 mM by dilution to increase the yield of hydrogen in batch light-supported fermentations. The thermophilic DFEs are suitable for photofermentative hydrogen production, provided that they are supplemented with buffer and nutrients. The overall hydrogen yield of the two-step fermentations was higher than the yield of single step dark fermentations.

  19. Screening of thermotolerant and thermophilic fungi aiming β-xylosidase and arabinanase production

    Directory of Open Access Journals (Sweden)

    Vivian Machado Benassi

    2014-12-01

    Full Text Available Plant cell wall is mainly composed by cellulose, hemicellulose and lignin. The heterogeneous structure and composition of the hemicellulose are key impediments to its depolymerization and subsequent use in fermentation processes. Thus, this study aimed to perform a screening of thermophilic and thermotolerant filamentous fungi collected from different regions of the São Paulo state, and analyze the production of β-xylosidase and arabinanase at different temperatures. These enzymes are important to cell wall degradation and synthesis of end products as xylose and arabinose, respectively, which are significant sugars to fermentation and ethanol production. A total of 12 fungal species were analyzed and 9 of them grew at 45 ºC, suggesting a thermophilic or thermotolerant character. Additionally Aspergillus thermomutatus anamorph of Neosartorya and A. parasiticus grew at 50 ºC. Aspergillus niger and Aspergillus thermomutatus were the filamentous fungi with the most expressive production of β-xylosidase and arabinanase, respectively. In general for most of the tested microorganisms, β-xylosidase and arabinanase activities from mycelial extract (intracellular form were higher in cultures grown at high temperatures (35-40 ºC, while the correspondent extracellular activities were favorably secreted from cultures at 30 ºC. This study contributes to catalogue isolated fungi of the state of São Paulo, and these findings could be promising sources for thermophilic and thermotolerant microorganisms, which are industrially important due to their enzymes.

  20. Proteins responsible for lysogeny of deep-sea thermophilic bacteriophage GVE2 at high temperature.

    Science.gov (United States)

    Song, Qing; Ye, Ting; Zhang, Xiaobo

    2011-06-15

    The lytic and lysogenic life cycle switch of bacteriophages plays very important roles in virus-host interactions. However, the lysogeny of thermophilic bacteriophage infecting thermophile at high temperatures has not been addressed. In this study, two lysogeny-related genes encoding the CI protein and recombinase of GVE2, a thermophilic bacteriophage obtained from a deep-sea hydrothermal vent, were characterized. Temporal analyses showed that the two genes were expressed at early stages of GVE2 infection. Based on chromatin immunoprecipitation (ChIP) assay and electrophoretic mobility shift assay (EMSA), the GVE2 CI protein was bound with only one DNA fragment located at 24264-24036 bp in the GVE2 genome. This location might be the original transcription site and the lysis-lysogeny switch site, which was very different from mesophilic bacteriophages. The GVE2 CI and recombinase proteins could function only at high temperatures. Therefore our study improved our understanding of the lysogeny process of bacteriophages at high temperatures. PMID:21303688

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

    Directory of Open Access Journals (Sweden)

    Tarik Aanniz

    2015-06-01

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

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

    Science.gov (United States)

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

    2015-06-01

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

  3. Start-up performances of dry anaerobic mesophilic and thermophilic digestions of organic solid wastes

    Institute of Scientific and Technical Information of China (English)

    LU Shu-guang; IMAI Tsuyoshi; UKITA Masao; SEKINE Masahiko

    2007-01-01

    Two dry anaerobic digestions of organic solid wastes were conducted for 6 weeks in a lab-scale batch experiment for investigating the start-up performances under mesophilic and thermophilic conditions. The enzymatic activities,i.e., β-glucosidase, β-glucosidase, N-α -benzoyl-L-argininamide (BAA)-hydrolysing protease, urease and phosphatase activities were analysed. The lower BAA-hydrolysing protease activity during the first 2-3 weeks was due to the inhibition of the low pH, but was enhanced simultaneously later with the pH increase. β-glucosidase activity showed the lowest values in weeks 1-2, and recovered simultaneously with the increase of BAA-hydrolysing protease activity. Acetic acid dominated most of the total VFAs in thermophilic digestion, while propionate and butyrate dominated in mesophilic digestion. Thermophilic digestion is confirmed more feasible for achieving better performance against misbalance, especially during the start-up period in a dry anaerobic digestion process.

  4. Developing a thermophilic hydrogen-producing co-culture for efficient utilization of mixed sugars

    Energy Technology Data Exchange (ETDEWEB)

    Zeidan, Ahmad A.; Van Niel, Ed W.J. [Department of Applied Microbiology, Lund University, P.O. Box 124, SE-221 00 Lund (Sweden)

    2009-05-15

    Previous studies on the extreme thermophile Caldicellulosiruptor saccharolyticus revealed that the organism produces high yields of hydrogen on glucose and xylose, the major components of lignocellulosic hydrolysates. Preliminary experiments on mixed sugar substrates, however, indicated that xylose was preferred over glucose. The sugar preference of some other extreme thermophiles, including Caldicellulosiruptor owensensis, Caldicellulosiruptor kristjanssonii and newly enriched, thermophilic compost sludge microflora, was investigated in an attempt to find complementary organisms to C. saccharolyticus for rapid and efficient utilization of lignocellulosic sugars. The behavior of C. owensensis and C. kristjanssonii appeared to be similar to that of C. saccharolyticus, either in pure cultures or in co-cultures with the latter. Co-culturing C. saccharolyticus with the enriched compost microflora resulted in fast, simultaneous consumption of both glucose and xylose in the medium with a relatively high specific hydrogen production rate, 40 mmol (gCDW){sup -1} h{sup -1}, and high volumetric productivity, 22.5 mmol l{sup -1} h{sup -1}. (author)

  5. High-solids enrichment of thermophilic microbial communities and their enzymes on bioenergy feedstocks

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, A. P.; Allgaier, M.; Singer, S.W.; Hazen, T.C.; Simmons, B.A.; Hugenholtz, P.; VanderGheynst, J.S.

    2011-04-01

    Thermophilic microbial communities that are active in a high-solids environment offer great potential for the discovery of industrially relevant enzymes that efficiently deconstruct bioenergy feedstocks. In this study, finished green waste compost was used as an inoculum source to enrich microbial communities and associated enzymes that hydrolyze cellulose and hemicellulose during thermophilic high-solids fermentation of the bioenergy feedstocks switchgrass and corn stover. Methods involving the disruption of enzyme and plant cell wall polysaccharide interactions were developed to recover xylanase and endoglucanase activity from deconstructed solids. Xylanase and endoglucanase activity increased by more than a factor of 5, upon four successive enrichments on switchgrass. Overall, the changes for switchgrass were more pronounced than for corn stover; solids reduction between the first and second enrichments increased by a factor of four for switchgrass while solids reduction remained relatively constant for corn stover. Amplicon pyrosequencing analysis of small-subunit ribosomal RNA genes recovered from enriched samples indicated rapid changes in the microbial communities between the first and second enrichment with the simplified communities achieved by the third enrichment. The results demonstrate a successful approach for enrichment of unique microbial communities and enzymes active in a thermophilic high-solids environment.

  6. Differential expression of extracellular thiol groups of moderately thermophilic Sulfobacillus thermosulfidooxidans and extremely thermophilic Acidianus manzaensis grown on S(0) and Fe (2.).

    Science.gov (United States)

    Liu, Hong-Chang; Xia, Jin-Lan; Nie, Zhen-Yuan; Zhen, Xiang-Jun; Zhang, Li-Juan

    2015-08-01

    Bio-oxidation of elemental sulfur (S(0)) is very important in bioleaching and sulfur cycle. S(0) was proposed to be first activated by reacting with reactive thiol groups (-SH) of outer membrane proteins, forming -S n H (n ≥ 2) complexes. The differential expression of -SH of moderately thermophilic Sulfobacillus thermosulfidooxidans and extremely thermophilic Acidianus manzaensis grown on Fe(2+) and S(0) was investigated by synchrotron radiation-based scanning transmission X-ray microscopy (STXM) imaging and micro-beam X-ray fluorescence (μ-XRF) mapping. The STXM imaging and μ-XRF mapping of extracellular -SH were based on the analysis of Ca(2+) bound on the cell. By comparing Ca(2+) of the cells with and without labeling by Ca(2+), the distribution and content of thiol groups were obtained. The results showed that, for both S. thermosulfidooxidans and A. manzaensis, the expression of extracellular -SH of S(0)-grown cells was higher than that of Fe(2+)-grown cells. Statistical analysis indicated that the expression of extracellular -SH for S. thermosulfidooxidans and A. manzaensis grown on S(0) was 2.37 times and 2.14 times, respectively, to that on Fe(2+). These results evidently demonstrate that the extracellular thiol groups are most probably involved in elemental sulfur activation and oxidation of the acidophilic sulfur-oxidizing microorganisms. PMID:25983134

  7. Differential expression of extracellular thiol groups of moderately thermophilic Sulfobacillus thermosulfidooxidans and extremely thermophilic Acidianus manzaensis grown on S(0) and Fe (2.).

    Science.gov (United States)

    Liu, Hong-Chang; Xia, Jin-Lan; Nie, Zhen-Yuan; Zhen, Xiang-Jun; Zhang, Li-Juan

    2015-08-01

    Bio-oxidation of elemental sulfur (S(0)) is very important in bioleaching and sulfur cycle. S(0) was proposed to be first activated by reacting with reactive thiol groups (-SH) of outer membrane proteins, forming -S n H (n ≥ 2) complexes. The differential expression of -SH of moderately thermophilic Sulfobacillus thermosulfidooxidans and extremely thermophilic Acidianus manzaensis grown on Fe(2+) and S(0) was investigated by synchrotron radiation-based scanning transmission X-ray microscopy (STXM) imaging and micro-beam X-ray fluorescence (μ-XRF) mapping. The STXM imaging and μ-XRF mapping of extracellular -SH were based on the analysis of Ca(2+) bound on the cell. By comparing Ca(2+) of the cells with and without labeling by Ca(2+), the distribution and content of thiol groups were obtained. The results showed that, for both S. thermosulfidooxidans and A. manzaensis, the expression of extracellular -SH of S(0)-grown cells was higher than that of Fe(2+)-grown cells. Statistical analysis indicated that the expression of extracellular -SH for S. thermosulfidooxidans and A. manzaensis grown on S(0) was 2.37 times and 2.14 times, respectively, to that on Fe(2+). These results evidently demonstrate that the extracellular thiol groups are most probably involved in elemental sulfur activation and oxidation of the acidophilic sulfur-oxidizing microorganisms.

  8. Effect of Addition of Base on Ceria and Reactivity of CuO/CeO2 Catalysts for Low-Temperature CO Oxidation

    Institute of Scientific and Technical Information of China (English)

    Xiucheng Zheng; Xiaoli Zhang; Shuping Wang; Xiangyu Wang; Shihua Wu

    2007-01-01

    In this work, we have reported the influence of the addition of base (KOH) on the physicochemical property of ceria synthesized by alcohothermal process, and the alcohothermal mechanism was also put forward. Furthermore, the prepared CeO2 was used as the support to prepare CuO/CeO2 catalysts via the wet impregnation method. The samples were characterized by N2 adsorption-desorption, X-ray powder diffraction (XRD), high resolution transmission electron microscopy (HRTEM), and temperatureprogrammed reduction by H2 (H2-TPR). The catalytic properties of the CuO/CeO2 catalysts for lowtemperature CO oxidation were studied using a microreactor-GC system. The crystal size of CeO2-A was much smaller than that of CeO2-B, and the corresponding copper oxide catalysts exhibited higher catalytic activity than that of the CeO2-B-supported catalysts under the same reaction conditions. The alcohothermal mechanism indicated that KOH plays a key role in determining the physicochemical and catalytic properties of ceria-based materials.

  9. Monte Carlo Simulation of CO Oxidation Reaction on Fractal Surface%分形表面上CO氧化反应的蒙特卡罗模拟

    Institute of Scientific and Technical Information of China (English)

    曾健青; 张镜澄; 钟炳

    1999-01-01

    The CO oxidation reaction on DLA fractal surface has been studied in detail by Monte Carlo method.It was found that (1) when only adsorption and surface reaction were considered the O atoms and CO molecules on surface would self-organize after a reation period,which greatly decreased the touching chance among different reactant molecules and consequently decreased the reaction rate.Furthermore,O atoms tended to be adsorbed at the center or the inner area of DLA surface while CO molecules could exist only at the exterior; (2) the clusters of O atoms could be cut off by vacant active sites after the introduction of CO diffusion on surface,which would further give rise to accelerateion of the reaction rate;(3) when the reversible adsorption of CO was introduced O atoms and CO molecules could adsorb evenly on the whole DLA surface and then the reaction would be speeded up greatly,which suggested that for a good catalyst the adsorbing strength should be moderate.

  10. Preparation of Hollow CuO@SiO2 Spheres and Its Catalytic Performances for the NO + CO and CO Oxidation

    Science.gov (United States)

    Niu, Xiaoyu; Zhao, Tieying; Yuan, Fulong; Zhu, Yujun

    2015-03-01

    The hollow CuO@SiO2 spheres with a mean diameter of 240 nm and a thin shell layer of about 30 nm in thickness was synthesized using an inorganic SiO2 shell coating on the surface of Cu@C composite that was prepared by a two-step hydrothermal method. The obtained hollow CuO@SiO2 spheres were characterized by ICP-AES, nitrogen adsorption-desorption, SEM, TEM, XRD, H2-TPR, CO-TPR, CO-TPD and NO-TPD. The results revealed that the hollow CuO@SiO2 spheres consist of CuO uniformly inserted into SiO2 layer. The CuO@SiO2 sample exhibits particular catalytic activities for CO oxidation and NO + CO reactions compared with CuO supported on SiO2 (CuO/SiO2). The higher catalytic activity is attributed to the special hollow shell structure that possesses much more highly dispersed CuO nanocluster that can be easy toward the CO and NO adsorption and the oxidation of CO on its surface.

  11. Active sites over CuO/CeO2 and inverse CeO2/CuO catalysts for preferential CO oxidation

    Science.gov (United States)

    Zeng, Shanghong; Wang, Yan; Ding, Suping; Sattler, Jesper J. H. B.; Borodina, Elena; Zhang, Lu; Weckhuysen, Bert M.; Su, Haiquan

    2014-06-01

    A series of CuO/CeO2 and inverse CeO2/CuO catalysts are prepared by the surfactant-templated method and characterized via XRD, HRTEM, H2-TPR, SEM, XPS, in situ XRD, in situ UV-Vis and N2 adsorption-desorption techniques. It is found that there are two kinds of surface sites in the CuO-CeO2 system, including CuO surface sites for CO chemisorption and CeO2 surface sites with oxygen vacancies for oxygen sorption. The active sites for CO oxidation are located on the contact interface of two-kind surface sites and the lattice oxygen can make a significant contribution to the CO-PROX reaction. The resistance to H2O and CO2 is related to BET surface area, the crystallite sizes of CuO and the reduction behavior of catalysts. The Ce4Cu4 and Ce4Cu1 catalysts exhibit the best resistance against H2O and CO2.

  12. Modeling mass transfer in solid oxide fuel cell anode: II. H2/CO co-oxidation and surface diffusion in synthesis-gas operation

    Science.gov (United States)

    Bao, Cheng; Jiang, Zeyi; Zhang, Xinxin

    2016-08-01

    Following the previous work on comparing performance of Fickian, Stefan-Maxwell and dusty-gas model for mass transfer in single fuel system, this article is focused on the electrochemistry and transport in the anode of solid oxide fuel cell using H2sbnd H2Osbnd COsbnd CO2sbnd N2 hybrid fuel. Under the standard framework of the dusty-gas model combined with the Butler-Volmer equation, it carries out a macroscopic area-specific modeling work. More specifically, two variables of hydrogen current fraction and enhancement factor are well defined and solved for the electrochemical co-oxidation of H2 and CO, and the diffusion equivalent circuit model is introduced to describe more comprehensively the resistance of mass transfer including molecular/Knudsen diffusion and surface diffusion. The model has been validated well in full region of Vsbnd I performance of an experimental anode-supported button cell. An approximate analytical solution of the hydrogen current fraction is also presented for explicit computation. Comparison between the results by different approaches for the effective diffusivity shows the importance of right mass-transfer modeling.

  13. A comparative DFT study on the CO oxidation reaction over Al- and Ge-embedded graphene as efficient metal-free catalysts

    Science.gov (United States)

    Esrafili, Mehdi D.; Nematollahi, Parisa; Abdollahpour, Hadi

    2016-08-01

    In the present study, by means of density functional theory (DFT) calculations, the catalytic oxidation of CO by O2 molecule is investigated over Al- and Ge-embedded graphene. The large atomic radius of these dopant atoms can induce a local surface curvature and modulate the electronic structure properties of the graphene sheet through the charge redistribution. It is found that the adsorption of molecular O2 over Al- or Ge-embedded graphene is stronger than that of CO molecule. The CO oxidation reaction by molecular O2 on Al- and Ge-embedded graphene is comparably studied. The results indicate that a two-step process can occur, namely, CO + O2 → CO2 + Oads and CO + Oads → CO2. Furthermore, the computed activation energy (Eact) for the first reaction on Ge-doped graphene is lower than that of Al-doped one, and the formation of second CO2 molecule on both surfaces can occur rapidly due to its low energy barrier (0.1 eV).

  14. SiO2–Ag–SiO2 core/shell structure with a high density of Ag nanoparticles for CO oxidation catalysis

    Science.gov (United States)

    Feng, Xiaoqian; Li, Hongmo; Zhang, Qing; Zhang, Peng; Song, Xuefeng; Liu, Jing; Zhao, Liping; Gao, Lian

    2016-11-01

    SiO2–Ag–SiO2, a sandwiched core/shell structure with a layer of Ag nanoparticles (∼4 nm) encapsulated between a shallow SiO2 surface layer and a SiO2 submicrosphere substrate (∼200 nm), has been synthesized from {{Ag}}{{({{{NH}}}3)}2}+ and SiO2 spheres by a facile one-pot hydrothermal method. The composite is proposed to result from the dynamic balance between the {{Ag}}{{({{{NH}}}3)}2}+ reduction and the dissolution-redeposition of SiO2 in mild basic media. The synthetic mechanism and the roles of the reaction time, temperature, and the amount of ammonia in the formation of this unique structure are investigated and discussed. The composite structure shows superior catalytic performance in CO oxidation to the control Ag/SiO2 structure prepared by impregnation. Pre-treatment by O2 at 600 °C significantly improves the catalytic performance of the composite structure and preserves the nanocomposite structure well.

  15. Physicochemical properties of manganese dioxide synthesized using C2–C5 alcohols as reducing agents and their catalytic activities for CO oxidation

    KAUST Repository

    Lee, Young-Ho

    2015-09-26

    MnO2 catalysts were synthesized in an aqueous solution of KMnO4 and C2–C5 alcohols using a simple redox method at room temperature. The crystalline structure of all samples was δ-MnO2 after being calcined at 300 °C. However, other physicochemical properties of the samples varied depending on the symmetry of the alcohols used. For the catalytic oxidation of CO, MnO2 catalysts prepared with 1° alcohols performed better than the samples prepared in 2° alcohols. Catalytic activities were correlated to the quantity of labile oxygen species of the catalysts. In CO-TPD analysis, the relative area of desorbed radical dotCO2, which is the product of the reaction between adsorbed CO and lattice oxygen species, becomes larger for MnO2 prepared with 1° alcohols than with 2° alcohols. These results were primarily resulted from the innate hydrogen dissociation behavior of alcohol in solution. The pKa was found to be an important factor in determining the physicochemical properties and catalytic activity toward CO oxidation of MnO2.

  16. Catalytic activity of nanostructured Au: Scale effects versus bimetallic/bifunctional effects in low-temperature CO oxidation on nanoporous Au

    Directory of Open Access Journals (Sweden)

    Lu-Cun Wang

    2013-02-01

    Full Text Available The catalytic properties of nanostructured Au and their physical origin were investigated by using the low-temperature CO oxidation as a test reaction. In order to distinguish between structural effects (structure–activity correlations and bimetallic/bifunctional effects, unsupported nanoporous gold (NPG samples prepared from different Au alloys (AuAg, AuCu by selective leaching of a less noble metal (Ag, Cu were employed, whose structure (surface area, ligament size as well as their residual amount of the second metal were systematically varied by applying different potentials for dealloying. The structural and chemical properties before and after 1000 min reaction were characterized by scanning electron microscopy (SEM, X-ray diffraction (XRD and X-ray photoelectron spectroscopy (XPS. The catalytic behavior was evaluated by kinetic measurements in a conventional microreactor and by dynamic measurements in a temporal analysis of products (TAP reactor. The data reveal a clear influence of the surface contents of residual Ag and Cu species on both O2 activation and catalytic activity, while correlations between activity and structural parameters such as surface area or ligament/crystallite size are less evident. Consequences for the mechanistic understanding and the role of the nanostructure in these NPG catalysts are discussed.

  17. Structure-activity relationship of Au-ZrO2 catalyst on formation of hydroxyl groups and its influence on CO oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Karwacki, Christopher J [US Army Aberdeen Proving Ground; Ganesh, Panchapakesan [ORNL; Kent, P. R. C. [University of Tennessee, Knoxville (UTK); Gordon, Wesley O [ORNL; Peterson, Gregory W [US Army Aberdeen Proving Ground; Niu, Jun Jie [Drexel University; Gogotsi, Yury G. [Drexel University

    2013-01-01

    The effect of changes in morphology and surface hydroxyl species upon thermal treatment of zirconia on the oxidation activity of Au/ZrO2 catalyst was studied. We observed using transmission Fourier transform infrared (FTIR) spectroscopy progressive changes in the presence of monodentate (type I), bidentate (type II) and hydrogen bridged species (type III) for each of the thermally treated (85 to 500 C) supports consisting of bare zirconia and Au/ZrO2 catalysts. Furthermore, structural changes in zirconia were accompanied by an increase in crystal size (7 to 58 nm) and contraction of the supports porosity (SSA 532 to 7 m2 g 1) with increasing thermal treatment. Deposition of gold nanoparticles under similar preparation conditions on different thermally treated zirconia resulted in changes in the mean gold cluster size, ranging from 3.7 to 5.6 nm. Changes in the surface hydroxyl species, support structure and size of the gold centers are important parameters responsible for the observed decrease (>90%) in CO conversion activity for the Au/ZrO2 catalysts. Density functional theory calculations provide evidence of increased CO binding to Au nanoclusters in the presence of surface hydroxyls on zirconia, which increases charge transfer at the perimeter of the gold nanocluster on zirconia support. This further helps in reducing a model CO-oxidation reaction barrier in the presence of surface hydroxyls. This work demonstrates the need to understand the structure activity relationship of both the support and active particles for the design of catalytic materials.

  18. The Distribution of Thermophilic Sulfate-reducing Bacteria Along an Estuarine Gradient Reveals Multiple Origins of Endospores in Estuarine Sediments

    Science.gov (United States)

    Bell, E.

    2015-12-01

    Cold marine sediments harbour inactive spores of thermophilic bacteria. These misplaced thermophiles are genetically similar to microorganisms detected in deep biosphere environments, leading to the hypothesis that seabed fluid flow transports thermophiles out of warm subsurface environments and into the ocean. Estuaries form the transition between the marine and the terrestrial biosphere and are influenced by tidal currents, surface run-off and groundwater seepage. Endospores from thermophilic bacteria present in estuarine sediments could therefore originate from a number of sources that may influence the estuary differently. We have therefore tested the hypothesis that this will lead to a gradient in the composition of thermophilic endospore populations in estuarine sediments. The distribution of thermophilic spore-forming sulfate-reducing bacteria along an estuarine gradient from freshwater (River Tyne, UK) to marine (North Sea) was investigated. Microbial community analysis by 16S rRNA gene amplicon sequencing revealed changes in the thermophilic population enriched at different locations within the estuary. Certain species were only detected at the marine end, highlighting possible links to deep marine biosphere habitats such as oil reservoirs that harbour closely related Desulfotomaculum spp. Conversely, other taxa were predominantly observed in the freshwater reaches of the estuary indicating dispersal from an upstream or terrestrial source. Different endospore populations were enriched dependent on incubation temperature and spore heat-resistance. Microcosms incubated at 50, 60 or 70°C showed a shift in the dominant species of Desulfotomaculum enriched as the temperature increased. Microcosms triple-autoclaved at 121°C prior to incubation still showed rapid and reproducible sulfate-reduction and some Desulfotomaculum spp. remained active after autoclaving at 130°C. These results show that temperature physiology and biogeographic patterns can be used to

  19. Heritability of aerobic power of individuals in northeast Brazil.

    Science.gov (United States)

    Alonso, L; Souza, Ec; Oliveira, Mv; do Nascimento, Lfe; Dantas, Pms

    2014-12-01

    The objective of this study was to evaluate the genetic and environmental contribution to variation in aerobic power in monozygotic (MZ) and dizygotic (DZ) twins. The sample consisted of 20 MZ individuals (12 females and 8 males) and 16 DZ individuals (12 females and 4 males), aged from 8 to 26 years, residents in Natal, Rio Grande do Norte. The twins were assessed by a multistage fitness test. The rate of heritability found for aerobic power was 77%. Based on the results, the estimated heritability was largely responsible for the differences in aerobic power. This implies that such measures are under strong genetic influence.

  20. Kallotenue papyrolyticum gen. nov., sp. nov., a cellulolytic and filamentous thermophile that represents a novel lineage (Kallotenuales ord. nov., Kallotenuaceae fam. nov.) within the class Chloroflexia

    Energy Technology Data Exchange (ETDEWEB)

    Cole, Jesse; Gieler, Brandon; Heisler, Devon; Palisoc, Maryknoll; Williams, Amanda; Dohnalkova, Alice; Ming, Hong; Yu, Tian T.; Dodsworth, Jeremy A.; Li, Wen J.; Hedlund, Brian P.

    2013-08-15

    Several closely-related, thermophilic, and cellulolytic bacterial strains, designated JKG1T, JKG2, JKG3, JKG4, and JKG5, were isolated from a cellulolytic enrichment (corn stover) incubated in the water column of Great Boiling Spring, NV. Strain JKG1T had cells of a diameter of 0.7 - 0.9 μm and length of ~2.0 μm that formed non-branched multicellular filaments reaching >300 μm. Spores were not formed and dense liquid cultures were red. The temperature range for growth was 45-65 °C, with an optimum of 55 °C. The pH range for growth was 5.6-9.0, with an optimum of 7.5. JKG1T grew as an aerobic heterotroph, utilizing glucose, sucrose, xylose, arabinose, cellobiose, carboxymethylcellulose, filter paper, microcrystalline cellulose, xylan, starch, casamino acids, tryptone, peptone, yeast extract, acetate, citrate, lactate, pyruvate, and glycerol as sole carbon sources, and was not observed to photosynthesize. The cells stained Gram-negative. Phylogenetic analysis using 16S rRNA gene sequences placed the new isolates in the class Chloroflexia, but distant from other cultivated members, with the highest sequence identity of 82.5% to Roseiflexus castenholzii. The major quinone was menaquinone-9; no ubiquinones were detected. The major cellular fatty acids (>5%) were C18:0, anteiso-C17:0, iso-C18:0, and iso-C17:0. C16:0, iso-C16:0, and C17:0. The peptidoglycan amino acids were alanine, ornithine, glutamic acid, serine, and asparagine. Whole-cell sugars included mannose, rhamnose, glucose, galactose, ribose, arabinose, and xylose. Morphological, phylogenetic, and chemotaxonomic results suggest that JKG1T is representative of a new lineage within the class Chloroflexia, which we propose to designate Kallotenue papyrolyticum gen. nov., sp. nov., Kallotenuaceae fam. nov., Kallotenuales ord. nov.

  1. Biochemical characterization of thermophilic lignocellulose degrading enzymes and their potential for biomass bioprocessing

    Directory of Open Access Journals (Sweden)

    Vasudeo Zambare, Archana Zambare, Kasiviswanath Muthukumarappan, Lew P. Christopher

    2011-01-01

    Full Text Available A thermophilic microbial consortium (TMC producing hydrolytic (cellulolytic and xylanolytic enzymes was isolated from yard waste compost following enrichment with carboxymethyl cellulose and birchwood xylan. When grown on 5% lignocellulosic substrates (corn stover and prairie cord grass at 600C, the thermophilic consortium produced more xylanase (up to 489 U/l on corn stover than cellulase activity (up to 367 U/l on prairie cord grass. Except for the carboxymethyl cellulose-enriched consortium, thermo-mechanical extrusion pretreatment of these substrates had a positive effect on both activities with up to 13% and 21% increase in the xylanase and cellulase production, respectively. The optimum temperatures of the crude cellulase and xylanase were 600C and 700C with half-lives of 15 h and 18 h, respectively, suggesting higher thermostability for the TMC xylanase. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the crude enzyme exhibited protein bands of 25-77 kDa with multiple enzyme activities containing 3 cellulases and 3 xylanases. The substrate specificity declined in the following descending order: avicel>birchwood xylan>microcrystalline cellulose>filter paper>pine wood saw dust>carboxymethyl cellulose. The crude enzyme was 77% more active on insoluble than soluble cellulose. The Km and Vmax values were 36.49 mg/ml and 2.98 U/mg protein on avicel (cellulase, and 22.25 mg/ml and 2.09 U/mg protein, on birchwood xylan (xylanase. A total of 50 TMC isolates were screened for cellulase and xylanase secretion on agar plates. All single isolates showed significantly lower enzyme activities when compared to the thermophilic consortia. This is indicative of the strong synergistic interactions that exist within the thermophilic microbial consortium and enhance its hydrolytic capabilities. It was further demonstrated that the thermostable enzyme-generated lignocellulosic hydrolyzates can be fermented to bioethanol by a recombinant strain of

  2. Biochemical characterization of thermophilic lignocellulose degrading enzymes and their potential for biomass bioprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Zambare, Vasudeo; Zambare, Archana; Christopher, Lew P. [Center for Bioprocessing Research & Development, South Dakota School of Mines and Technology, Rapid City 57701, SD (United States); Muthukumarappan, Kasiviswanath [Center for Bioprocessing Research & Development, South Dakota State University, Brookings 57007, SD (United States)

    2011-07-01

    A thermophilic microbial consortium (TMC) producing hydrolytic (cellulolytic and xylanolytic) enzymes was isolated from yard waste compost following enrichment with carboxymethyl cellulose and birchwood xylan. When grown on 5% lignocellulosic substrates (corn stover and prairie cord grass) at 60C, the thermophilic consortium produced more xylanase (up to 489 U/l on corn stover) than cellulase activity (up to 367 U/l on prairie cord grass). Except for the carboxymethyl cellulose-enriched consortium, thermo-mechanical extrusion pretreatment of these substrates had a positive effect on both activities with up to 13% and 21% increase in the xylanase and cellulase production, respectively. The optimum temperatures of the crude cellulase and xylanase were 60C and 70C with half-lives of 15 h and 18 h, respectively, suggesting higher thermostability for the TMC xylanase. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the crude enzyme exhibited protein bands of 25-77 kDa with multiple enzyme activities containing 3 cellulases and 3 xylanases. The substrate specificity declined in the following descending order: avicel>birchwood xylan>microcrystalline cellulose>filter paper>pine wood saw dust>carboxymethyl cellulose. The crude enzyme was 77% more active on insoluble than soluble cellulose. The Km and Vmax values were 36.49 mg/ml and 2.98 U/mg protein on avicel (cellulase), and 22.25 mg/ml and 2.09 U/mg protein, on birchwood xylan (xylanase). A total of 50 TMC isolates were screened for cellulase and xylanase secretion on agar plates. All single isolates showed significantly lower enzyme activities when compared to the thermophilic consortia. This is indicative of the strong synergistic interactions that exist within the thermophilic microbial consortium and enhance its hydrolytic capabilities. It was further demonstrated that the thermostable enzyme-generated lignocellulosic hydrolyzates can be fermented to bioethanol by a recombinant strain of Escherichia coli

  3. Enhanced aerobic nitrifying granulation by static magnetic field.

    Science.gov (United States)

    Wang, Xin-Hua; Diao, Mu-He; Yang, Ying; Shi, Yi-Jing; Gao, Ming-Ming; Wang, Shu-Guang

    2012-04-01

    One of the main challenging issues for aerobic nitrifying granules in treating high strength ammonia wastewater is the long granulation time required for activated sludge to transform into aerobic granules. The present study provides a novel strategy for enhancing aerobic nitrifying granulation by applying an intensity of 48.0mT static magnetic field. The element analysis showed that the applied magnetic field could promote the accumulation of iron compounds in the sludge. And then the aggregation of iron decreased the full granulation time from 41 to 25days by enhancing the setting properties of granules and stimulating the secretion of extracellular polymeric substances (EPS). Long-term, cycle experiments and fluorescence in-situ hybridization (FISH) analysis proved that an intensity of 48.0mT magnetic field could enhance the activities and growth of nitrite-oxidizing bacteria (NOB). These findings suggest that magnetic field is helpful and reliable for accelerating the aerobic nitrifying granulation.

  4. THE RELATIONSHIP OF CHOREOGRAPHY PREPARATION AND ARTISTRY IN AEROBIC GYMNASTICS

    Directory of Open Access Journals (Sweden)

    I. V. Sokolova

    2015-02-01

    Full Text Available Examines the impact choreography training in sports aerobics on artistic skills.Objective to investigate whether the use of funds choreo-graphy in training athletes involved in sports aerobics, to find the relationship between choreographic training and asses-sment for artistry.Method or methodology of work methods of studying the theoretical ski works of scientific content, analysis and processing of scientific texts.The results revealed the relationship between estimates for artistry and means-you dance training in sports aerobics. The scope of the results, the materials may be used by coaches in sports aerobics, for further research on the problem of constructing workout.

  5. WAYS TO IMPROVE THE PHYSICAL FITNESS THROUGH AEROBIC GYMNASTICS MEANS

    Directory of Open Access Journals (Sweden)

    Zaharia A.M.

    2013-07-01

    Full Text Available This research aimed to study the probable effects that aerobic gymnastics could have on the body, for improving the physical fitness. The main goal of the research was to identify the effects the aerobic gymnastics has in improving physical fitness.This research was conducted on 15 subjects between 18 and 30 years old, who participated in aerobic gymnastics fitness-type lessons, three times a week. The programs comprised exercises of physical development , stretching and elasticity, of relaxation, of coordination, and not in the least, of muscle strengthening. In order to evaluate the effectiveness of the applied means, the Ruffier test was used to assess the physical fitness of the subjects, and the Dorgo Index, to assess the cool-down response. The research data emphasized the subjects' interest for their physical fitness through a dynamic activity, constituting an argument for the practice of aerobic gymnastics throughout one's entire life, as a mean to preserve one's youth and beauty.

  6. Aerobic training and postexercise protein in facioscapulohumeral muscular dystrophy

    DEFF Research Database (Denmark)

    Andersen, Grete; Prahm, Kira P; Dahlqvist, Julia R;

    2015-01-01

    OBJECTIVE: To investigate the effect of regular aerobic training and postexercise protein-carbohydrate supplementation in patients with facioscapulohumeral muscular dystrophy (FSHD). METHODS: In this randomized, double-blind, placebo-controlled parallel study, we randomized untrained men (n = 21...

  7. Nitrifying and denitrifying bacteria in aerobic granules formed in sequencing batch airlift reactors

    Institute of Scientific and Technical Information of China (English)

    WANG Fang; YANG Fenglin; QI Aijiu

    2007-01-01

    The purpose of this study was to investigate nitrifying bacteria and denitrifying bacteria isolated from aerobic granules.Aerobic granules were formed in an internal-circulate sequencing batch airlift reactor(SBAR)and biodegradation of NH3 -N was analyzed in the reactor.Bacteria were isolated and determined from aerobic granules using selected media.The growth properties and morphology of bacteria colonies were observed by controlling aerobic or anaerobic conditions in the culture medium.It was found that bacteria in aerobic granules were diverse and some of them were facultative aerobes.The diversity of bacteria in aerobic granules was a premise of simultaneous nitrification and denitrification.

  8. Fate of selected emerging micropollutants during mesophilic, thermophilic and temperature co-phased anaerobic digestion of sewage sludge.

    Science.gov (United States)

    Samaras, Vasilios G; Stasinakis, Athanasios S; Thomaidis, Nikolaos S; Mamais, Daniel; Lekkas, Themistokles D

    2014-06-01

    The removal of endocrine disrupting compounds (EDCs) and non-steroidal anti-inflammatory drugs (NSAIDs) was studied in three lab-scale anaerobic digestion (AD) systems; a single-stage mesophilic, a single-stage thermophilic and a two-stage thermophilic/mesophilic. All micropollutants underwent microbial degradation. High removal efficiency (>80%) was calculated for diclofenac, ibuprofen, naproxen and ketoprofen; whereas triclosan, bisphenol A and the sum of nonylphenol (NP), nonylphenol monoethoxylate (NP1EO) and nonylphenol diethoxylate were moderately removed (40-80%). NSAIDs removal was not affected by the type of AD system used; whereas slightly higher EDCs removal was observed in two-stage system. In this system, most microcontaminants were removed in thermophilic digester. Biotransformation of NP1EO and NP was affected by the temperature applied to bioreactors. Under mesophilic conditions, higher removal of NP1EO and accumulation of NP was noticed; whereas the opposite was observed under thermophilic conditions. For most analytes, higher specific removal rates were calculated under thermophilic conditions and 20 days SRT. PMID:24768891

  9. Semi-continuous solid substrate anaerobic reactors for H{sub 2} production from organic waste: Mesophilic versus thermophilic regime

    Energy Technology Data Exchange (ETDEWEB)

    Valdez-Vazquez, Idania; Rios-Leal, Elvira; Esparza-Garcia, Fernando; Poggi-Varaldo, Hector M. [CINVESTAV-IPN, Department Biotechnology and Bioengineering, Environmental Biotechnology, P.O. Box 14-740, Mexico D.F. 07000 (Mexico); Cecchi, Franco [Universita degli Studi di Verona, Verona (Italy)

    2005-11-01

    We evaluated the influence of the operation temperature (mesophilic vs. thermophilic regime) of semicontinuous, acidogenic solid substrate anaerobic digestion (A-SSAD) of the organic fraction of municipal solid waste (OFMSW) at lab scale. The H{sub 2} percentage was higher in the thermophilic regime than in the mesophilic operation (58% and 42%, respectively). The H{sub 2} yield of thermophilic A-SSAD was significantly higher than in our mesophilic reactors (360 vs. 165NmL H{sub 2}/g VS{sub rem}) and other studies reported in the literature (range of 62-180mL/g VS). Mesophilic A-SSAD showed a yield of 37% of the maximum yield based on 4molH{sub 2}/mol hexose, while thermophilic A-SSAD exhibited a yield of 80% of the maximum yield. This result is similar to works with pure cultures of extremophile microorganisms where H{sub 2} yields of 83% of the maximum were reported. We found higher concentrations of acetic acid in the digestates of thermophilic A-SSAD, while butyrate was in higher proportion in mesophilic A-SSAD spent solids. The moderate-to-high yields obtained with the semicontinuous process used in this work are in disagreement with previous reports claiming that batch and semicontinuous processes are less efficient than continuous ones. (author)

  10. Aerobic and Anaerobic Starvation Metabolism in Methanotrophic Bacteria

    OpenAIRE

    Roslev, P.; King, G. M.

    1995-01-01

    The capacity for anaerobic metabolism of endogenous and selected exogenous substrates in carbon- and energy-starved methanotrophic bacteria was examined. The methanotrophic isolate strain WP 12 survived extended starvation under anoxic conditions while metabolizing 10-fold less endogenous substrate than did parallel cultures starved under oxic conditions. During aerobic starvation, the cell biomass decreased by 25% and protein and lipids were the preferred endogenous substrates. Aerobic prote...

  11. p53 aerobics: the major tumor suppressor fuels your workout.

    Science.gov (United States)

    Kruse, Jan-Philipp; Gu, Wei

    2006-07-01

    In addition to its role as the central regulator of the cellular stress response, p53 can regulate aerobic respiration via the novel transcriptional target SCO2, a critical regulator of the cytochrome c oxidase complex (Matoba et al., 2006). Loss of p53 results in decreased oxygen consumption and aerobic respiration and promotes a switch to glycolysis, thereby reducing endurance during physical exercise. PMID:16814724

  12. Dosing method of physical activity in aerobics classes for students

    OpenAIRE

    Beliak Yu. I.; Zinchenko N.M.

    2014-01-01

    Purpose : reasons for the method of dosing of physical activity in aerobics classes for students. The basis of the method is the evaluation of the metabolic cost of funds used in them. Material : experiment involved the assessment of the pulse response of students to load complexes classical and step aerobics (n = 47, age 20-23 years). In complexes used various factors regulating the intensity: perform combinations of basic steps, involvement of movements with his hands, holding in hands dumb...

  13. Water aerobics in pregnancy: cardiovascular response, labor and neonatal outcomes

    OpenAIRE

    Braga Angelica F; Cecatti Jose G; Pereira Rosa I; Baciuk Erica P; Cavalcante Sergio R

    2008-01-01

    Abstract Background To evaluate the association between water aerobics, maternal cardiovascular capacity during pregnancy, labor and neonatal outcomes. Methods A randomized, controlled clinical trial was carried out in which 34 pregnant women were allocated to a water aerobics group and 37 to a control group. All women were submitted to submaximal ergometric tests on a treadmill at 19, 25 and 35 weeks of pregnancy and were followed up until delivery. Oxygen consumption (VO2 max), cardiac outp...

  14. Audio Processing Solution for Video Conference Based Aerobics

    OpenAIRE

    Berggren, Magnus; Stjernberg, Louise; Lindström, Fredric; Claesson, Ingvar

    2010-01-01

    In this paper an audio processing solution for video conference based aerobics is presented. The proposed solution leaves the workout music unaltered by separating it from the speech and processing each signal separately. The speech signal processing is also performed at a lower sample rate, which saves computational power. Real time evaluation of the system shows that high quality music as well as a good two-way communication is maintained during the aerobic session.

  15. Fetal cardiotocography before and after water aerobics during pregnancy

    OpenAIRE

    Silveira Carla; Pereira Belmiro G; Cecatti Jose G; Cavalcante Sergio R; Pereira Rosa I

    2010-01-01

    Abstract Objective To evaluate the effect of moderate aerobic physical activity in water on fetal cardiotocography patterns in sedentary pregnant women. Method In a non-randomized controlled trial, 133 previously sedentary pregnant women participated in multiple regular sessions of water aerobics in a heated swimming pool. Cardiotocography was performed for 20 minutes before and just after the oriented exercise. Cardiotocography patterns were analyzed pre- and post-exercise according to gesta...

  16. Impact of brisk walking and aerobics in overweight women

    OpenAIRE

    Melam, Ganeswara Rao; Alhusaini, Adel A.; Buragadda, Syamala; Kaur, Taranpreet; Khan, Imran Ali

    2016-01-01

    [Purpose] Lack of physical activity and an uncontrolled diet cause excessive weight gain, which leads to obesity and other metabolic disorders. Studies have indicated that brisk walking and aerobics are the best methods for controlling and reducing weight and body mass composition. [Subjects and Methods] In this study, 45 overweight women were enrolled and divided into 3 groups. Women not involved in brisk walking or aerobics were included in group A (n = 15) as control subjects; women involv...

  17. THE RELATIONSHIP OF CHOREOGRAPHY PREPARATION AND ARTISTRY IN AEROBIC GYMNASTICS

    OpenAIRE

    I. V. Sokolova

    2015-01-01

    Examines the impact choreography training in sports aerobics on artistic skills.Objective to investigate whether the use of funds choreo-graphy in training athletes involved in sports aerobics, to find the relationship between choreographic training and asses-sment for artistry.Method or methodology of work methods of studying the theoretical ski works of scientific content, analysis and processing of scientific texts.The results revealed the relationship between estimates for artistry and me...

  18. The medically important aerobic actinomycetes: epidemiology and microbiology.

    OpenAIRE

    McNeil, M. M.; Brown, J. M.

    1994-01-01

    The aerobic actinomycetes are soil-inhabiting microorganisms that occur worldwide. In 1888, Nocard first recognized the pathogenic potential of this group of microorganisms. Since then, several aerobic actinomycetes have been a major source of interest for the commercial drug industry and have proved to be extremely useful microorganisms for producing novel antimicrobial agents. They have also been well known as potential veterinary pathogens affecting many different animal species. The medic...

  19. Water Aerobics as a Form of Health Activities

    Directory of Open Access Journals (Sweden)

    Anna S. Batrak

    2013-09-01

    Full Text Available The offered literature review considers water aerobics as a form of health activities. Water aerobics is wide spread and popular, especially among women, because it is also the form of adaptive and health activities. It enlarges general physiological effect of physical exercises on the human body. Regular exercises improve physical fitness and physical development, health, mood, sleep, intensify activities and working efficiency.

  20. Maximal aerobic exercise following prolonged sleep deprivation.

    Science.gov (United States)

    Goodman, J; Radomski, M; Hart, L; Plyley, M; Shephard, R J

    1989-12-01

    The effect of 60 h without sleep upon maximal oxygen intake was examined in 12 young women, using a cycle ergometer protocol. The arousal of the subjects was maintained by requiring the performance of a sequence of cognitive tasks throughout the experimental period. Well-defined oxygen intake plateaus were obtained both before and after sleep deprivation, and no change of maximal oxygen intake was observed immediately following sleep deprivation. The endurance time for exhausting exercise also remained unchanged, as did such markers of aerobic performance as peak exercise ventilation, peak heart rate, peak respiratory gas exchange ratio, and peak blood lactate. However, as in an earlier study of sleep deprivation with male subjects (in which a decrease of treadmill maximal oxygen intake was observed), the formula of Dill and Costill (4) indicated the development of a substantial (11.6%) increase of estimated plasma volume percentage with corresponding decreases in hematocrit and red cell count. Possible factors sustaining maximal oxygen intake under the conditions of the present experiment include (1) maintained arousal of the subjects with no decrease in peak exercise ventilation or the related respiratory work and (2) use of a cycle ergometer rather than a treadmill test with possible concurrent differences in the impact of hematocrit levels and plasma volume expansion upon peak cardiac output and thus oxygen delivery to the working muscles. PMID:2628360

  1. Personality, metabolic rate and aerobic capacity.

    Directory of Open Access Journals (Sweden)

    Antonio Terracciano

    Full Text Available Personality traits and cardiorespiratory fitness in older adults are reliable predictors of health and longevity. We examined the association between personality traits and energy expenditure at rest (basal metabolic rate and during normal and maximal sustained walking. Personality traits and oxygen (VO(2 consumption were assessed in 642 participants from the Baltimore Longitudinal Study of Aging. Results indicate that personality traits were mostly unrelated to resting metabolic rate and energy expenditure at normal walking pace. However, those who scored lower on neuroticism (r = -0.12 and higher on extraversion (r = 0.11, openness (r = 0.13, and conscientiousness (r = 0.09 had significantly higher energy expenditure at peak walking pace. In addition to greater aerobic capacity, individuals with a more resilient personality profile walked faster and were more efficient in that they required less energy per meter walked. The associations between personality and energy expenditure were not moderated by age or sex, but were in part explained by the proportion of fat mass. In conclusion, differences in personality may matter the most during more challenging activities that require cardiorespiratory fitness. These findings suggest potential pathways that link personality to health outcomes, such as obesity and longevity.

  2. Aerobic training in children with cerebral palsy.

    Science.gov (United States)

    Nsenga, A L; Shephard, R J; Ahmaidi, S; Ahmadi, S

    2013-06-01

    Rehabilitation is a major goal for children with cerebral palsy, although the potential to enhance cardio-respiratory fitness in such individuals remains unclear. This study thus compared current cardio-respiratory status between children with cerebral palsy and able-bodied children, and examined the ability to enhance the cardio-respiratory fitness of children with cerebral palsy by cycle ergometer training. 10 children with cerebral palsy (Gross Motor Function Classification System levels I and II) participated in thrice-weekly 30 min cycle ergometer training sessions for 8 weeks (mean age: 14.2±1.9 yrs). 10 additional subjects with cerebral palsy (mean age: 14.2±1.8 yrs) and 10 able-bodied subjects (mean age: 14.1±2.1 yrs) served as controls, undertaking no training. All subjects undertook a progressive cycle ergometer test of cardio-respiratory fitness at the beginning and end of the 8-week period. Cardio-respiratory parameters [oxygen intake V˙O2), ventilation V ˙ E) and heart rate (HR)] during testing were measured by Cosmed K4 b gas analyzer. The children with cerebral palsy who engaged in aerobic training improved their peak oxygen consumption, heart rate and ventilation significantly (pchildren with cerebral palsy can benefit significantly from cardio-respiratory training, and such training should be included in rehabilitation programs.

  3. Energy efficient aerobic treatment of forest industry wastewaters; Energieffektiv aerob rening av skogsindustriella avloppsvatten

    Energy Technology Data Exchange (ETDEWEB)

    Sandberg, Maria; From-Aldaron, Mattias

    2011-01-15

    There is great potential to reduce energy requirements in aerobic biological purification if the oxygen demand can be reduced and oxygen delivery, when process water is aerated, is made more efficient. A model was developed to estimate the possible reduction in oxygen demand. Model variables were COD reduction, sludge withdrawal, oxygen, and alpha-value. Attempts made in an aerator in the lab-scale process shows that water content strongly affects oxygen transport and alpha-value. Surface active extract substances such as fatty acids and resin acids have greatest significance. The effect increases with the concentration of extract substances and decreases with added sodium chloride content

  4. Effect of thermal additions on the density and distribution of thermophilic amoebae and pathogenic Naegleria fowleri in a newly created cooling lake

    Energy Technology Data Exchange (ETDEWEB)

    Tyndall, R.L.; Ironside, K.S.; Metler, P.L.; Tan, E.L. (Univ. of Tennessee, Knoxville (USA)); Hazen, T.C.; Fliermans, C.B. (E.I. du Pont de Nemours and Co., Inc., Aiken, SC (USA))

    1989-03-01

    Pathogenic Naegleria fowleri is the causative agent of fatal human amoebic meningoencephalitis. The protozoan is ubiquitous in nature, and its presence is enhanced by thermal additions. In this investigation, water and sediments from a newly created cooling lake were quantitatively analyzed for the presence of thermophilic amoebae, thermophilic Naegleria spp., and the pathogen Naegleria fowleri. During periods of thermal additions, the concentrations of thermophilic amoebae and thermophilic Naegleria spp. increased as much as 5 orders of magnitude, and the concentration of the pathogen N. fowleri increased as much as 2 orders of magnitude. Concentrations of amoebae returned to prior thermal perturbation levels within 30 to 60 days after cessation of thermal additions. Increases in the thermophilic amoeba concentrations were noted in Savannah River oxbows downriver from the Savannah River plant discharge streams as compared with oxbows upriver from the discharges. Concentrations of thermophilic amoebae and thermophilic Naegleria spp. correlated significantly with temperature and conductivity. Air samples taken proximal to the lade during periods of thermal addition showed no evidence of thermophilic Naegleria spp. Isoenzyme patterns of the N. fowleri isolated from the cooling lake were identical to patterns of N. fowleri isolated from other sites in the United States and Belgium.

  5. The Training Effects of Dance Aerobics: A Review with an Emphasis on the Perspectives of Investigations

    OpenAIRE

    Zaletel, Petra; Gabrilo, Goran; Perić, Mia

    2013-01-01

    The training effects of contemporary aerobics programmes (hi lo, dance aerobics, step aerobics, aqua aerobics etc.) have been frequently investigated. However, we found no recent paper which reviewed aerobic programmes with regard to their training effectiveness, characteristics of the subjects involved, variables of interest and experimental design. In this paper we summarise the findings of more than 40 studies published in the 2000–2011 period that investigated the training effects of diff...

  6. Oxygen vacancy promoted CO oxidation over Pt/CeO{sub 2} catalysts: A reaction at Pt–CeO{sub 2} interface

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Huan-Huan; Wang, Yu; Jia, Ai-Pin; Wang, Shu-Yuan; Luo, Meng-Fei; Lu, Ji-Qing, E-mail: jiqinglu@zjnu.cn

    2014-09-30

    Graphical abstract: - Highlights: • The reaction rate r = k{sub app}[CO]{sup 0}[O{sub 2}]{sup 0} was independent of CO and O{sub 2} partial pressure. • A Mars van-Krevelen model was proposed for the elementary steps. • A reaction between chemisorbed CO on Pt and lattice oxygen at Pt–CeO{sub 2} interface. • Turnover frequencies increased with Pt particle size for the Pt/CeO{sub 2} catalysts. • Higher concentration of oxygen vacancies was important for the enhanced activity. - Abstract: A series of Pt/CeO{sub 2} catalysts with different Pt contents were prepared using an incipient wetness impregnation method and tested for CO oxidation. Kinetic study on the catalysts indicated that the reaction rate was independent of the partial pressures of CO and O{sub 2} (r = k{sub app}[CO]{sup 0}[O{sub 2}]{sup 0}). The derived reaction pathways involved chemisorption of CO on surface Pt atoms and reacting with lattice oxygen provided by the CeO{sub 2} support at the Pt–CeO{sub 2} interface, suggesting a Mars van-Krevelen type reaction on these catalysts and the interfacial Pt–O–Ce ensembles being the active sites. Also, turnover frequencies (TOFs) calculated based on Pt dispersion and periphery Pt atoms were found to be proportional to the Pt particle size, with the large Pt particles possessing higher TOF than the small ones. Such a trend was interpreted by the important role of the oxygen vacancies via the formation of Pt–Ce–O solid solution, which could accelerate the mobility of lattice oxygen and consequently the activity.

  7. Oxygen vacancy promoted CO oxidation over Pt/CeO2 catalysts: A reaction at Pt–CeO2 interface

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • The reaction rate r = kapp[CO]0[O2]0 was independent of CO and O2 partial pressure. • A Mars van-Krevelen model was proposed for the elementary steps. • A reaction between chemisorbed CO on Pt and lattice oxygen at Pt–CeO2 interface. • Turnover frequencies increased with Pt particle size for the Pt/CeO2 catalysts. • Higher concentration of oxygen vacancies was important for the enhanced activity. - Abstract: A series of Pt/CeO2 catalysts with different Pt contents were prepared using an incipient wetness impregnation method and tested for CO oxidation. Kinetic study on the catalysts indicated that the reaction rate was independent of the partial pressures of CO and O2 (r = kapp[CO]0[O2]0). The derived reaction pathways involved chemisorption of CO on surface Pt atoms and reacting with lattice oxygen provided by the CeO2 support at the Pt–CeO2 interface, suggesting a Mars van-Krevelen type reaction on these catalysts and the interfacial Pt–O–Ce ensembles being the active sites. Also, turnover frequencies (TOFs) calculated based on Pt dispersion and periphery Pt atoms were found to be proportional to the Pt particle size, with the large Pt particles possessing higher TOF than the small ones. Such a trend was interpreted by the important role of the oxygen vacancies via the formation of Pt–Ce–O solid solution, which could accelerate the mobility of lattice oxygen and consequently the activity

  8. Kinetic Study of Oxygen Adsorption over Nanosized Au/γ-Al2O3 Supported Catalysts under Selective CO Oxidation Conditions

    Directory of Open Access Journals (Sweden)

    George Karaiskakis

    2012-04-01

    Full Text Available O2 adsorption is a key process for further understanding the mechanism of selective CO oxidation (SCO on gold catalysts. Rate constants related to the elementary steps of O2 adsorption, desorption and surface bonding, as well as the respective activation energies, over a nanosized Au/γ-Al2O3 catalyst, were determined by Reversed-Flow Inverse Gas Chromatography (RF-IGC. The present study, carried-out in a wide temperature range (50–300 °C, both in excess as well as in the absence of H2, resulted in mechanistic insights and kinetic as well as energetic comparisons, on the sorption processes of SCO reactants. In the absence of H2, the rate of O2 binding, over Au/γ-Al2O3, drastically changes with rising temperature, indicating possible O2 dissociation at elevated temperatures. H2 facilitates stronger O2 bonding at higher temperatures, while low temperature binding remains practically unaffected. The lower energy barriers observed, under H2 rich conditions, can be correlated to O2 dissociation after hydrogenation. Although, H2 enhances both selective CO reactant’s desorption, O2 desorption is more favored than that of CO, in agreement with the well-known mild bonding of SCO reactant’s at lower temperatures. The experimentally observed drastic change in the strength of CO and O2 binding is consistent both with well-known high activity of SCO at ambient temperatures, as well as with the loss of selectivity at higher temperatures.

  9. Kinetic Study of Oxygen Adsorption over Nanosized Au/γ-Al2O3 Supported Catalysts under Selective CO Oxidation Conditions

    Directory of Open Access Journals (Sweden)

    George Karaiskakis

    2012-04-01

    Full Text Available O2 adsorption is a key process for further understanding the mechanism of selective CO oxidation (SCO on gold catalysts. Rate constants related to the elementary steps of O2 adsorption, desorption and surface bonding, as well as the respective activation energies, over a nanosized Au/γ-Al2O3 catalyst, were determined by Reversed-Flow Inverse Gas Chromatography (RF-IGC. The present study, carried-out in a wide temperature range (50–300 °C, both in excess as well as in the absence of H2, resulted in mechanistic insights and kinetic as well as energetic comparisons, on the sorption processes of SCO reactants. In the absence of H2, the rate of O2 binding, over Au/γ-Al2O3, drastically changes with rising temperature, indicating possible O2 dissociation at elevated temperatures. H2 facilitates stronger O2 bonding at higher temperatures, while low temperature binding remains practically unaffected. The lower energy barriers observed, under H2 rich conditions, can be correlated to O2 dissociation after hydrogenation. Although, H2 enhances both selective CO reactant’s desorption, O2 desorption is more favored than that of CO, in agreement with the well-known mild bonding of SCO reactant’s at lower temperatures. The experimentally observed drastic change in the strength of CO and O2 binding is consistent both with well-known high activity of SCO at ambient temperatures, as well as with the loss of selectivity at higher temperatures.

  10. Unique properties of ceria nanoparticles supported on metals: novel inverse ceria/copper catalysts for CO oxidation and the water-gas shift reaction.

    Science.gov (United States)

    Senanayake, Sanjaya D; Stacchiola, Dario; Rodriguez, Jose A

    2013-08-20

    a standard catalyst for reactions such as CO oxidation and the water-gas shift (WGS). This metal serves as an ideal replacement for other noble metals that are neither abundant nor cost effective. To prepare the inverse system we deposited nanoparticles (2-20 nm) of cerium oxide onto the Cu(111) surface. During this process, the Cu(111) surface grows an oxide layer that is characteristic of Cu₂O (Cu¹⁺). This oxide can influence the growth of ceria nanoparticles. Evidence suggests triangular-shaped CeO₂(111) grows on Cu₂O(111) surfaces while rectangular CeO₂(100) grows on Cu₄O₃(111) surfaces. We used the CeOx/Cu₂O/Cu(111) inverse system to study two catalytic processes: the WGS (CO + H₂O → CO₂ + H₂) and CO oxidation (2CO + O₂ → 2CO₂). We discovered that the addition of small amounts of ceria nanoparticles can activate the Cu(111) surface and achieve remarkable enhancement of catalytic activity in the investigated reactions. In the case of the WGS, the CeOx nanoparticle facilitated this process by acting at the interface with Cu to dissociate water. In the CO oxidation case, an enhancement in the dissociation of O₂ by the nanoparticles was a key factor. The strong interaction between CeOx nanoparticles and Cu(111) when preoxidized and reduced in CO resulted in a massive surface reconstruction of the copper substrate with the introduction of microterraces that covered 25-35% of the surface. This constitutes a new mechanism for surface reconstruction not observed before. These microterraces helped to facilitate a further enhancement of activity towards the WGS by opening an additional channel for the dissociation of water. In summary, inverse catalysts of CeOx/Cu(111) and CeO₂/Cu₂O/Cu(111) demonstrate the versatility of a model system to obtain insightful knowledge of catalytic processes. These systems will continue to offer a unique opportunity to probe key catalytic components and elucidate the relationship between structure and

  11. Supplementary Low-Intensity Aerobic Training Improves Aerobic Capacity and Does Not Affect Psychomotor Performance in Professional Female Ballet Dancers

    OpenAIRE

    Smol, Ewelina; Fredyk, Artur

    2012-01-01

    We investigated whether 6-week low-intensity aerobic training program used as a supplement to regular dance practice might improve both the aerobic capacity and psychomotor performance in female ballet dancers. To assess their maximal oxygen uptake (VO2max) and anaerobic threshold (AT), the dancers performed a standard graded bicycle ergometer exercise test until volitional exhaustion prior to and after the supplementary training. At both these occasions, the psychomotor performance (assessed...

  12. Cooperative role of electrical stimulation on microbial metabolism and selection of thermophilic communities for p-fluoronitrobenzene treatment.

    Science.gov (United States)

    Zhang, Xueqin; Shen, Dongsheng; Feng, Huajun; Wang, Yanfeng; Li, Na; Han, Jingyi; Long, Yuyang

    2015-01-01

    A novel thermophilic bioelectrochemical system (TBES) based on electrical stimulation was established for the enhanced treatment of p-fluoronitrobenzene (p-FNB) wastewater. p-FNB removal rate constant in the TBES was 78.6% higher than that of the mesophilic BES (MBES), the elevation of which owing to high-temperature overtook the rate improvement of 50.8% in the electrocatalytic system (ECS). Additionally, an overwhelming mineralization efficiency of 91.96% ± 5.70% was obtained in the TBES. The superiority of TBES was attributed to the integrated role of electrical stimulation and high-temperature. Electrical stimulation provided an alternative for the microbial growth independent energy requirements, compensating insufficient energy support from p-FNB metabolism under the high-temperature stress. Besides, electrical stimulation facilitated microbial community evolution to form specific thermophilic biocatalysis. The uniquely selected thermophilic microorganisms including Coprothermobacter sp. and other ones cooperated to enhance p-FNB mineralization.

  13. Study on the production of enzymes from thermophiles%嗜热菌产酶现状的研究

    Institute of Scientific and Technical Information of China (English)

    潘丽贞; 陆利霞; 熊晓辉

    2012-01-01

    嗜热菌是应用最广泛的一种极端微生物,而其产生的酶在工业催化中有着广泛的应用。阐述了嗜热菌产脂肪酶、脱卤酶以及葡糖醛酸酯酶等几种酶的研究现状。%Thermophiles are a kind of extremophiles which are most widely used,and the enzymes produced by thermophiles are also widely used in industrial catalysis.The recent studies on the production of enzymes from thermophiles,such as lipase,dehalogenase,glucuronoyl esterase etc were summarized.

  14. Formation and functions of aerobic microbial granula; Entstehung und Funktionen aerober mikrobieller Granula

    Energy Technology Data Exchange (ETDEWEB)

    Etterer, T.; Wilderer, P.A. [Technische Univ. Muenchen, Garching (Germany). Lehrstuhl und Pruefamt fuer Wasserguete- und Abfallwirtschaft

    1999-07-01

    The present project investigates the phenomenon of the formation of aerobic microbial granula and their properties. To generate granula, sequencing batch reactors fed in batches were used. As shown by microbiological assays, fungi played an above-average role in granula formation and build-up. In first degradation experiments, furthermore, chemical oxygen demand (COD) could be reduced by over 90 %. The determination yielded comparable values to activated sludge, standing on average at 1.044g/ml. (orig.) [German] Im Rahmen des hier vorgestellten Projekts wurde das Phaenomen der Bildung aerober mikrobieller Granula sowie deren Eigenschaften untersucht. Zur Erzeugung von Granula wurden schubweise beschickte Reaktoren, sogenannte Sequencing-Batch-Reaktoren (SBR) verwendet. Wie mikrobiologische Untersuchungen zeigten spielen Pilze bei der Entstehung und beim Aufbau eine ueberdurchschnittliche Rolle. Des weiteren konnte in ersten Abbauversuchen der chemische Sauerstoff-Bedarf (CSB) um ueber 90% gesenkt werden. Die Dichtebestimmung ergab vergleichbare Werte zu Belebtschlamm und zwar im Durchschnitt 1,044 g/ml. (orig.)

  15. Enhanced selection of micro-aerobic pentachlorophenol degrading granular sludge

    International Nuclear Information System (INIS)

    Graphical abstract: In this work, an aerobic column reactor was placed before the USB to maintain micro-oxygen condition in the reactor and the micro-aerobic pentachlorophenol (PCP) degrading granular sludge under oxygen-limited conditions (0.1–0.2 mg L−1) was successfully obtained. PCP degradation by the micro-aerobic system was studied and the variance of microbial community was also discussed by using PCR-DGGE analysis. - Highlights: • Micro-aerobic granular sludge was cultivated in column-type combined reactors. • PCP biodegradation, VFA accumulation and biogas production were studied. • The function of Methanogenic archaeon in the system was investigated. • Fluctuation and diversity of microbial community were discussed by DGGE analysis. • The dominated microorganisms were identified by 16S rDNA sequences. - Abstract: Column-type combined reactors were designed to cultivate micro-aerobic pentachlorophenol (PCP) degrading granular sludge under oxygen-limited conditions (0.1–0.2 mg L−1) over 39-day experimental period. Micro-aerobic granular had both anaerobic activity (SMA: 2.34 mMCH4/h g VSS) and aerobic activity (SOUR: 2.21 mMO2/h g VSS). Metabolite analysis results revealed that PCP was sequentially dechlorinated to TCP, DCP, and eventually to MCP. Methanogens were not directly involved in the dechlorination of PCP, but might played a vital role in stabilizing the overall structure of the granule sludge. For Eubacteria, the Shannon Index (2.09 in inoculated granular sludge) increased both in micro-aerobic granular sludge (2.61) and PCP-degradation granular sludge (2.55). However, for Archaea, it decreased from 2.53 to 1.85 and 1.84, respectively. Although the Shannon Index demonstrated slight difference between micro-aerobic granular sludge and PCP-degradation granular sludge, the Principal Component Analysis (PCA) indicated obvious variance of the microbial composition, revealing significant effect of micro-aerobic condition and PCP on

  16. Enhanced selection of micro-aerobic pentachlorophenol degrading granular sludge

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Yuancai, E-mail: donkey1204@hotmail.com [State Key Laboratory of Pulp and Paper Engineering, College of Light Industry and Food Science, South China University of Technology, Guangzhou 510640 (China); Chen, Yuancai, E-mail: chenyc@scut.edu.cn [State Key Laboratory of Pulp and Paper Engineering, College of Light Industry and Food Science, South China University of Technology, Guangzhou 510640 (China); Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, College of Environment and Energy, South China University of Technology, Guangzhou 510006 (China); Song, Wenzhe, E-mail: songwenzhe007@126.com [Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, College of Environment and Energy, South China University of Technology, Guangzhou 510006 (China); Hu, Yongyou, E-mail: ppyyhu@scut.edu.cn [State Key Laboratory of Pulp and Paper Engineering, College of Light Industry and Food Science, South China University of Technology, Guangzhou 510640 (China); Ministry of Education Key Laboratory of Pollution Control and Ecological Remediation for Industrial Agglomeration Area, College of Environment and Energy, South China University of Technology, Guangzhou 510006 (China)

    2014-09-15

    Graphical abstract: In this work, an aerobic column reactor was placed before the USB to maintain micro-oxygen condition in the reactor and the micro-aerobic pentachlorophenol (PCP) degrading granular sludge under oxygen-limited conditions (0.1–0.2 mg L{sup −1}) was successfully obtained. PCP degradation by the micro-aerobic system was studied and the variance of microbial community was also discussed by using PCR-DGGE analysis. - Highlights: • Micro-aerobic granular sludge was cultivated in column-type combined reactors. • PCP biodegradation, VFA accumulation and biogas production were studied. • The function of Methanogenic archaeon in the system was investigated. • Fluctuation and diversity of microbial community were discussed by DGGE analysis. • The dominated microorganisms were identified by 16S rDNA sequences. - Abstract: Column-type combined reactors were designed to cultivate micro-aerobic pentachlorophenol (PCP) degrading granular sludge under oxygen-limited conditions (0.1–0.2 mg L{sup −1}) over 39-day experimental period. Micro-aerobic granular had both anaerobic activity (SMA: 2.34 mMCH{sub 4}/h g VSS) and aerobic activity (SOUR: 2.21 mMO{sub 2}/h g VSS). Metabolite analysis results revealed that PCP was sequentially dechlorinated to TCP, DCP, and eventually to MCP. Methanogens were not directly involved in the dechlorination of PCP, but might played a vital role in stabilizing the overall structure of the granule sludge. For Eubacteria, the Shannon Index (2.09 in inoculated granular sludge) increased both in micro-aerobic granular sludge (2.61) and PCP-degradation granular sludge (2.55). However, for Archaea, it decreased from 2.53 to 1.85 and 1.84, respectively. Although the Shannon Index demonstrated slight difference between micro-aerobic granular sludge and PCP-degradation granular sludge, the Principal Component Analysis (PCA) indicated obvious variance of the microbial composition, revealing significant effect of micro-aerobic

  17. Characteristic features in the structure and collagen-binding ability of a thermophilic collagenolytic protease from the thermophile Geobacillus collagenovorans MO-1.

    Science.gov (United States)

    Itoi, Yuichi; Horinaka, Mano; Tsujimoto, Yoshiyuki; Matsui, Hiroshi; Watanabe, Kunihiko

    2006-09-01

    A collagen-degrading thermophile, Geobacillus collagenovorans MO-1, extracellularly produces a collagenolytic protease with a large molecular mass. Complete nucleotide sequencing of this gene after gene cloning revealed that the collagenolytic protease is a member of the subtilisin family of serine proteases and consists of a signal sequence for secretion, a prosequence for maturation, a catalytic region, 14 direct repeats of 20 amino acids at the C terminus, and a region with unknown function intervening between the catalytic region and the numerous repeats. Since the unusual repeats are most likely to be cleaved in the secreted form of the enzyme, the intervening region was investigated to determine whether it participates in collagen binding to facilitate collagen degradation. It was found that the mature collagenolytic protease containing the intervening region at the C terminus bound collagen but not the other insoluble proteins, elastin and keratin. Furthermore, the intervening region fused with glutathione S-transferase showed a collagen-binding ability comparable to that of the mature collagenolytic protease. The collagen-binding ability was finally attributed to two-thirds of the intervening region which is rich in beta-strands and is approximately 35 kDa in molecular mass. In the collagenolytic protease from strain MO-1, hydrogen bonds most likely predominate over the hydrophobic interaction for collagen binding, since a higher concentration of NaCl released collagen from the enzyme surface but a nonionic detergent could not. To the best of our knowledge, this is the first report of a thermophilic collagenolytic protease containing the collagen-binding segment.

  18. Highly thermostable xylanase production from a thermophilic Geobacillus sp. strain WSUCF1 utilizing lignocellulosic biomass

    Directory of Open Access Journals (Sweden)

    Aditya eBhalla

    2015-06-01

    Full Text Available AbstractEfficient enzymatic hydrolysis of lignocellulose to fermentable sugars requires a complete repertoire of biomass deconstruction enzymes. Hemicellulases play an important role in hydrolyzing hemicellulose component of lignocellulose to xylo-oligosaccharides and xylose. Thermostable xylanases have been a focus of attention as industrially important enzymes due to their long shelf life at high temperatures. Geobacillus sp. strain WSUCF1 produced thermostable xylanase activity (crude xylanase cocktail when grown on xylan or various inexpensive untreated and pretreated lignocellulosic biomasses such as prairie cord grass and corn stover. The optimum pH and temperature for the crude xylanase cocktail were 6.5 and 70ºC, respectively. The WSUCF1 crude xylanase was found to be highly thermostable with half-lives of 18 and 12 days at 60 and 70ºC, respectively. At 70ºC, rates of xylan hydrolysis were also found to be better with the WSUCF1 secretome than those with commercial enzymes, i.e., for WSUCF1 crude xylanase, CellicHTec2, and AccelleraseXY, the percent xylan conversions were 68.9, 49.4, and 28.92, respectively. To the best of our knowledge, WSUCF1 crude xylanase cocktail is among the most thermostable xylanases produced by thermophilic Geobacillus spp. and other thermophilic microbes (optimum growth temperature ≤70ºC. High thermostability, activity over wide range of temperatures, and better xylan hydrolysis than commercial enzymes make WSUCF1 crude xylanase suitable for thermophilic lignocellulose bioconversion processes.

  19. High yield simultaneous hydrogen and ethanol production under extreme-thermophilic (70 C) mixed culture environment

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Chenxi [Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084 (China); Department of Environmental Engineering, Technical University of Denmark, DK-2800, Kgs Lyngby (Denmark); O-Thong, Sompong [Department of Biology, Faculty of Science, Thaksin University, Patthalung 93110 (Thailand); Karakashev, Dimitar; Angelidaki, Irini [Department of Environmental Engineering, Technical University of Denmark, DK-2800, Kgs Lyngby (Denmark); Lu, Wenjing; Wang, Hongtao [Department of Environmental Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2009-07-15

    The effect of pH and medium composition on extreme-thermophilic (70 C) dark fermentative simultaneous hydrogen and ethanol production (process performance and microbial ecology) was investigated. Hydrogen and ethanol yields were optimized with respect to glucose, peptone, FeSO{sub 4}, NaHCO{sub 3}, yeast extract, trace mineral salts, vitamins, and phosphate buffer concentrations as well as initial pH as independent variables. A combination of low levels of both glucose ({<=}2 g/L) and vitamin solutions ({<=}1 mL/L) and high levels of initial pH ({>=}7), mineral salts solution ({>=}5 mL/L) and FeSO{sub 4} ({>=}100 mg/L) stimulated the hydrogen production, while high level of glucose ({>=}5 g/L) and low levels of both initial pH ({<=}5.5) and mineral salts solution ({<=}1 mL/L) enhanced the ethanol production. High yield of simultaneous hydrogen and ethanol production (1.58 mol H{sub 2}/mol glucose combined with an ethanol yield of 0.90 mol ethanol/mol glucose) was achieved under extreme-thermophilic mixed culture environment. Results obtained showed that the shift of the metabolic pathways favouring either hydrogen or ethanol production was affected by the change in cultivation conditions (pH and medium composition). The mixed culture in this study demonstrated flexible ability for simultaneous hydrogen and ethanol production, depending on pH and nutrients formulation. The microorganisms involved could be regarded as simultaneous hydrogen/ethanol producers, as hydrogen and ethanol fermentation under all conditions was carried out by a group of extreme-thermophilic bacterial species related to Thermoanaerobacter, Thermoanaerobacterium and Caldanaerobacter. (author)

  20. Ultrasound-mediated DNA transformation in thermophilic gram-positive anaerobes.

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    Lu Lin

    Full Text Available BACKGROUND: Thermophilic, Gram-positive, anaerobic bacteria (TGPAs are generally recalcitrant to chemical and electrotransformation due to their special cell-wall structure and the low intrinsic permeability of plasma membranes. METHODOLOGY/PRINCIPAL FINDINGS: Here we established for any Gram-positive or thermophiles an ultrasound-based sonoporation as a simple, rapid, and minimally invasive method to genetically transform TGPAs. We showed that by applying a 40 kHz ultrasound frequency over a 20-second exposure, Texas red-conjugated dextran was delivered with 27% efficiency into Thermoanaerobacter sp. X514, a TGPA that can utilize both pentose and hexose for ethanol production. Experiments that delivered plasmids showed that host-cell viability and plasmid DNA integrity were not compromised. Via sonoporation, shuttle vectors pHL015 harboring a jellyfish gfp gene and pIKM2 encoding a Clostridium thermocellum β-1,4-glucanase gene were delivered into X514 with an efficiency of 6x10(2 transformants/µg of methylated DNA. Delivery into X514 cells was confirmed via detecting the kanamycin-resistance gene for pIKM2, while confirmation of pHL015 was detected by visualization of fluorescence signals of secondary host-cells following a plasmid-rescue experiment. Furthermore, the foreign β-1,4-glucanase gene was functionally expressed in X514, converting the host into a prototypic thermophilic consolidated bioprocessing organism that is not only ethanologenic but cellulolytic. CONCLUSIONS/SIGNIFICANCE: In this study, we developed an ultrasound-based sonoporation method in TGPAs. This new DNA-delivery method could significantly improve the throughput in developing genetic systems for TGPAs, many of which are of industrial interest yet remain difficult to manipulate genetically.