WorldWideScience

Sample records for thermophilic temperature optimum

  1. NOAA Daily Optimum Interpolation Sea Surface Temperature

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The NOAA 1/4° daily Optimum Interpolation Sea Surface Temperature (or daily OISST) is an analysis constructed by combining observations from different platforms...

  2. Force-dependent melting of supercoiled DNA at thermophilic temperatures.

    Science.gov (United States)

    Galburt, E A; Tomko, E J; Stump, W T; Ruiz Manzano, A

    2014-01-01

    Local DNA opening plays an important role in DNA metabolism as the double-helix must be melted before the information contained within may be accessed. Cells finely tune the torsional state of their genomes to strike a balance between stability and accessibility. For example, while mesophilic life forms maintain negatively superhelical genomes, thermophilic life forms use unique mechanisms to maintain relaxed or even positively supercoiled genomes. Here, we use a single-molecule magnetic tweezers approach to quantify the force-dependent equilibrium between DNA melting and supercoiling at high temperatures populated by Thermophiles. We show that negatively supercoiled DNA denatures at 0.5 pN lower tension at thermophilic vs. mesophilic temperatures. This work demonstrates the ability to monitor DNA supercoiling at high temperature and opens the possibility to perform magnetic tweezers assays on thermophilic systems. The data allow for an estimation of the relative energies of base-pairing and DNA bending as a function of temperature and support speculation as to different general mechanisms of DNA opening in different environments. Lastly, our results imply that average in vivo DNA tensions range between 0.3 and 1.1 pN. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Properties of thermophilic microorganisms

    International Nuclear Information System (INIS)

    Ljungdahl, L.G.

    1984-01-01

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

  4. Temperature effects on sulfate permease in a thermophile and related mesophile

    International Nuclear Information System (INIS)

    Wang, J.L.; Woodin, T.

    1986-01-01

    The activity and stability of a specific membrane function, sulfate permease, from Penicillium duponti (PD) a thermophilic fungus capable of growth between 30 and 58 0 and from Pencilium chrysogenum (PC) a mesophial capable of growth between 4 and 33 0 were compared to determine whether such activity reflects actual or optimal growth temperature. Permease was assayed by incubating derepressed mycelia (grown in media containing 1.0 mg/l cysteic acid instead of 1.0 g/l SO 4 ) with radioactive sulfate, collecting mycelia at 30 sec intervals and counting the 35 S incorporated into mycelial pellets. Mycelia from cells grown at 8 0 (PC only), 30 0 (PC and PD) or 50 0 (PD only) were assayed. The temperature optimum from PC cells grown at either 8 or 30 0 is 25 0 , while the temperature optimum from PD cells grown at either 30 or 50 0 is 45 0 . However the specific activity of the permease, the shape of the temperature optimum curve and the stability of the permease vary dramatically with the growth temperature and growth stage of the mycelia. There is an apparent ability to compensate for growth at lower temperature by either an increase in permease specific activity in 30 0 grown PD cells or a broadening of the temperature optimum curve for 8 0 grown PC. Transfer of cells grown in complete media (citrate No. 3 containing 4% glucose and 1 g/l sodium sulfate) to media lacking sulfate also results in derepression for sulfate permease. The time course and maximum amount of derepression observed reflects fungal growth temperature

  5. Optimum Temperature and Thermal Stability of Crude Polyphenol ...

    African Journals Online (AJOL)

    The optimum temperature was found to be 300C for the enzyme extracted from guava, ... processing industries because during the processing ... enhance the brown colour produced (Valero et al., ... considerable economic and nutritional loss.

  6. 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.

  7. Optimum development temperature and duration for nuclear plate

    International Nuclear Information System (INIS)

    Nagoshi, Chieko.

    1975-01-01

    Sakura 100 μm thick nuclear plates have been employed to determine optimum temperature and duration of the Amidol developer for low energy protons (Ep 0 C were tried for periods of 15--35 min. For Ep 0 C and for development time less than 30 min. (auth.)

  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. Optimum hot water temperature for absorption solar cooling

    Energy Technology Data Exchange (ETDEWEB)

    Lecuona, A.; Ventas, R.; Venegas, M.; Salgado, R. [Dpto. Ingenieria Termica y de Fluidos, Universidad Carlos III de Madrid, Avda. Universidad 30, 28911 Leganes, Madrid (Spain); Zacarias, A. [ESIME UPA, IPN, Av. de las Granjas 682, Col. Santa Catarina, 02550, D.F. Mexico (Mexico)

    2009-10-15

    The hot water temperature that maximizes the overall instantaneous efficiency of a solar cooling facility is determined. A modified characteristic equation model is used and applied to single-effect lithium bromide-water absorption chillers. This model is based on the characteristic temperature difference and serves to empirically calculate the performance of real chillers. This paper provides an explicit equation for the optimum temperature of vapor generation, in terms of only the external temperatures of the chiller. The additional data required are the four performance parameters of the chiller and essentially a modified stagnation temperature from the detailed model of the thermal collector operation. This paper presents and discusses the results for small capacity machines for air conditioning of homes and small buildings. The discussion highlights the influence of the relevant parameters. (author)

  10. Dewaterability of thermophilically digested biosolids: effects of temperature and cellular polymeric substances

    International Nuclear Information System (INIS)

    Zhou, J.; Mavinic, D.S.; Kelly, H.G.; Ramey, W.D.

    2002-01-01

    Thermophilic processes digest sludge at high temperatures to produce Class A biosolids.Recent research work revealed that digestion temperature is the predominant factor affecting dewaterability of thermophilic biosolids. This paper presents findings of a laboratory study that investigated how various digestion temperatures affect dewaterability of digested biosolids, studied the phase partition of the substances affecting dewaterability in digested biosolids, and tested the role of cellular polymeric substances in affecting dewaterability.Secondary sludges were digested at 40-70 o C or 22 o C for up to 12 days. Centrate from thermophilically digested biosolids were treated with protease and boiling. This study found that, during the first few hours of digestion, higher temperatures resulted in more rapid and more significant deterioration in dewaterability than lower digestion temperatures. Continued digestion resulted in either improved (60 o C or 70 o C), or unchanged (40 o C or 50 o C), or gradually deteriorated dewaterability (22 o C). The substances affecting dewaterability were primarily located in the liquid phase of thermophilically digested biosolids. Boiling treatment did not result in significant changes in dewaterability. Protease treatment of the liquid phase of thermophilic biosolids improved dewaterability by 13-19%. Such an improvement confirmed the role of proteins in affecting dewaterability. (author)

  11. Empowering a mesophilic inoculum for thermophilic nitrification: Growth mode and temperature pattern as critical proliferation factors for archaeal ammonia oxidizers.

    Science.gov (United States)

    Courtens, Emilie N P; Vandekerckhove, Tom; Prat, Delphine; Vilchez-Vargas, Ramiro; Vital, Marius; Pieper, Dietmar H; Meerbergen, Ken; Lievens, Bart; Boon, Nico; Vlaeminck, Siegfried E

    2016-04-01

    Cost-efficient biological treatment of warm nitrogenous wastewaters requires the development of thermophilic nitrogen removal processes. Only one thermophilic nitrifying bioreactor was described so far, achieving 200 mg N L(-1) d(-1) after more than 300 days of enrichment from compost samples. From the practical point of view in which existing plants would be upgraded, however, a more time-efficient development strategy based on mesophilic nitrifying sludge is preferred. This study evaluated the adaptive capacities of mesophilic nitrifying sludge for two linear temperature increase patterns (non-oscillating vs. oscillating), two different slopes (0.25 vs. 0.08 °C d(-1)) and two different reactor types (floc vs. biofilm growth). The oscillating temperature pattern (0.25 °C d(-1)) and the moving bed biofilm reactor (0.08 °C d(-1)) could not reach nitrification at temperatures higher than 46 °C. However, nitrification rates up to 800 mg N L(-1) d(-1) and 150 mg N g(-1) volatile suspended solids d(-1) were achieved at a temperature as high as 49 °C by imposing the slowest linear temperature increase to floccular sludge. Microbial community analysis revealed that this successful transition was related with a shift in ammonium oxidizing archaea dominating ammonia oxidizing bacteria, while for nitrite oxidation Nitrospira spp. was constantly more abundant than Nitrobacter spp.. This observation was accompanied with an increase in observed sludge yield and a shift in maximal optimum temperature, determined with ex-situ temperature sensitivity measurements, predicting an upcoming reactor failure at higher temperature. Overall, this study achieved nitrification at 49 °C within 150 days by gradual adaptation of mesophilic sludge, and showed that ex-situ temperature sensitivity screening can be used to monitor and steer the transition process. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. 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......, as well as with the addition of freeze-dried Spirulina or individual high-molecular-weight polysaccharides. During 50°C incubation experiments, Arctic thermophiles catalysed extensive mineralization of the organic matter via extracellular enzymatic hydrolysis, fermentation and sulfate reduction. This high...... reactivity determined the extent of the thermophilic response. Fjord sediments with higher in situ SRR also supported higher SRR at 50°C. Amendment with Spirulina significantly increased volatile fatty acids production and SRR relative to unamended sediment in 50°C incubations. Spirulina amendment also...

  13. Catalytic properties of thermophilic lactate dehydrogenase and halophilic malate dehydrogenase at high temperature and low water activity.

    Science.gov (United States)

    Hecht, K; Wrba, A; Jaenicke, R

    1989-07-15

    Thermophilic lactate dehydrogenases from Thermotoga maritima and Bacillus stearothermophilus are stable up to temperature limits close to the optimum growth temperature of their parent organisms. Their catalytic properties are anomalous in that Km shows a drastic increase with increasing temperature. At low temperatures, the effect levels off. Extreme halophilic malate dehydrogenase from Halobacterium marismortui exhibits a similar anomaly. Increasing salt concentration (NaCl) leads to an optimum curve for Km, oxaloacctate while Km, NADH remains constant. Previous claims that the activity of halophilic malate dehydrogenase shows a maximum at 1.25 M NaCl are caused by limiting substrate concentration; at substrate saturation, specific activity of halophilic malate dehydrogenase reaches a constant value at ionic strengths I greater than or equal to 1 M. Non-halophilic (mitochondrial) malate dehydrogenase shows Km characteristics similar to those observed for the halophilic enzyme. The drastic decrease in specific activity of the mitochondrial enzyme at elevated salt concentrations is caused by the salt-induced increase in rigidity of the enzyme, rather than gross structural changes.

  14. Differences in the catalytic mechanisms of mesophilic and thermophilic indole-3-glycerol phosphate synthase enzymes at their adaptive temperatures.

    Science.gov (United States)

    Zaccardi, Margot J; Mannweiler, Olga; Boehr, David D

    2012-02-10

    Thermophilic enzymes tend to be less catalytically-active at lower temperatures relative to their mesophilic counterparts, despite having very similar crystal structures. An often cited hypothesis for this general observation is that thermostable enzymes have evolved a more rigid tertiary structure in order to cope with their more extreme, natural environment, but they are also less flexible at lower temperatures, leading to their lower catalytic activity under mesophilic conditions. An alternative hypothesis, however, is that complementary thermophilic-mesophilic enzyme pairs simply operate through different evolutionary-optimized catalytic mechanisms. In this communication, we present evidence that while the steps of the catalytic mechanisms for mesophilic and thermophilic indole-3-glycerol phosphate synthase (IGPS) enzymes are fundamentally similar, the identity of the rate-determining step changes as a function of temperature. Our findings indicate that while product release is rate-determining at 25°C for thermophilic IGPS, near its adaptive temperature (75°C), a proton transfer event, involving a general acid, becomes rate-determining. The rate-determining steps for thermophilic and mesophilic IGPS enzymes are also different at their respective, adaptive temperatures with the mesophilic IGPS-catalyzed reaction being rate-limited before irreversible CO2 release, and the thermophilic IGPS-catalyzed reaction being rate limited afterwards. Copyright © 2012 Elsevier Inc. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    Arnauld Vinçon-Laugier

    2017-08-01

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

  16. Effect of temperature on bacterial species diversity in thermophilic solid-waste composting.

    OpenAIRE

    Strom, P F

    1985-01-01

    Continuously thermophilic composting was examined with a 4.5-liter reactor placed in an incubator maintained at representative temperatures. Feed was a mixture of dried table scraps and shredded newspaper wetted to 55% moisture. One run at 49 degrees C (run A) employed a 1:4 feed-to-compost ratio, while the other runs used a 10:1 ratio and were incubated at 50, 55, 60, or 65 degrees C. Due to self-heating, internal temperatures of the composting mass were 0 to 7 degrees C hotter than the incu...

  17. Differences in the catalytic mechanisms of mesophilic and thermophilic indole-3-glycerol phosphate synthase enzymes at their adaptive temperatures

    International Nuclear Information System (INIS)

    Zaccardi, Margot J.; Mannweiler, Olga; Boehr, David D.

    2012-01-01

    Highlights: ► Catalytic mechanisms of thermophilic–mesophilic enzymes may differ. ► Product release is rate-determining for thermophilic IGPS at low temperatures. ► But at higher temperatures, proton transfer from the general acid is rate-limiting. ► Rate-determining step is different still for mesophilic IGPS. ► Both chemical and physical steps of catalysis are important for temperature adaptation. -- Abstract: Thermophilic enzymes tend to be less catalytically-active at lower temperatures relative to their mesophilic counterparts, despite having very similar crystal structures. An often cited hypothesis for this general observation is that thermostable enzymes have evolved a more rigid tertiary structure in order to cope with their more extreme, natural environment, but they are also less flexible at lower temperatures, leading to their lower catalytic activity under mesophilic conditions. An alternative hypothesis, however, is that complementary thermophilic–mesophilic enzyme pairs simply operate through different evolutionary-optimized catalytic mechanisms. In this communication, we present evidence that while the steps of the catalytic mechanisms for mesophilic and thermophilic indole-3-glycerol phosphate synthase (IGPS) enzymes are fundamentally similar, the identity of the rate-determining step changes as a function of temperature. Our findings indicate that while product release is rate-determining at 25 °C for thermophilic IGPS, near its adaptive temperature (75 °C), a proton transfer event, involving a general acid, becomes rate-determining. The rate-determining steps for thermophilic and mesophilic IGPS enzymes are also different at their respective, adaptive temperatures with the mesophilic IGPS-catalyzed reaction being rate-limited before irreversible CO 2 release, and the thermophilic IGPS-catalyzed reaction being rate limited afterwards.

  18. Thermophilic Fungi: Their Physiology and Enzymes†

    Science.gov (United States)

    Maheshwari, Ramesh; Bharadwaj, Girish; Bhat, Mahalingeshwara K.

    2000-01-01

    Thermophilic fungi are a small assemblage in mycota that have a minimum temperature of growth at or above 20°C and a maximum temperature of growth extending up to 60 to 62°C. As the only representatives of eukaryotic organisms that can grow at temperatures above 45°C, the thermophilic fungi are valuable experimental systems for investigations of mechanisms that allow growth at moderately high temperature yet limit their growth beyond 60 to 62°C. Although widespread in terrestrial habitats, they have remained underexplored compared to thermophilic species of eubacteria and archaea. However, thermophilic fungi are potential sources of enzymes with scientific and commercial interests. This review, for the first time, compiles information on the physiology and enzymes of thermophilic fungi. Thermophilic fungi can be grown in minimal media with metabolic rates and growth yields comparable to those of mesophilic fungi. Studies of their growth kinetics, respiration, mixed-substrate utilization, nutrient uptake, and protein breakdown rate have provided some basic information not only on thermophilic fungi but also on filamentous fungi in general. Some species have the ability to grow at ambient temperatures if cultures are initiated with germinated spores or mycelial inoculum or if a nutritionally rich medium is used. Thermophilic fungi have a powerful ability to degrade polysaccharide constituents of biomass. The properties of their enzymes show differences not only among species but also among strains of the same species. Their extracellular enzymes display temperature optima for activity that are close to or above the optimum temperature for the growth of organism and, in general, are more heat stable than those of the mesophilic fungi. Some extracellular enzymes from thermophilic fungi are being produced commercially, and a few others have commercial prospects. Genes of thermophilic fungi encoding lipase, protease, xylanase, and cellulase have been cloned and

  19. NOAA Optimum Interpolation 1/4 Degree Daily Sea Surface Temperature (OISST) Analysis, Version 2

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This high-resolution sea surface temperature (SST) analysis product was developed using an optimum interpolation (OI) technique. The SST analysis has a spatial grid...

  20. [Gradient elevation of temperature startup experiment of thermophilic ASBR treating thermal-hydrolyzed sewage sludge].

    Science.gov (United States)

    Ouyang, Er-Ming; Wang, Wei; Long, Neng; Li, Huai

    2009-04-15

    Startup experiment was conducted for thermophilic anaerobic sequencing batch reactor (ASBR) treating thermal-hydrolyzed sewage sludge using the strategy of the step-wise temperature increment: 35 degrees C-->40 degrees C-->47 degrees C-->53 degrees C. The results showed that the first step-increase (from 35 degrees C to 40 degrees C) and final step-increase (from 47 degrees C to 53 degrees C) had only a slight effect on the digestion process. The second step-increase (from 40 degrees C to 47 degrees C) resulted in a severe disturbance: the biogas production, methane content, CODeffluent and microorganism all have strong disturbance. At the steady stage of thermophilic ASBR treating thermal-hydrolyzed sewage sludge, the average daily gas production, methane content, specific methane production (CH4/CODinfluent), TCOD removal rate and SCOD removal rate were 2.038 L/d, 72.0%, 188.8 mL/g, 63.8%, 83.3% respectively. The results of SEM and DGGE indicated that the dominant species are obviously different at early stage and steady stage.

  1. Mesophilic and thermophilic anaerobic digestion of primary and secondary sludge. Effect of pre-treatment at elevated temperature

    DEFF Research Database (Denmark)

    Gavala, Hariklia N.; Yenal, U.; Skiadas, Ioannis V.

    2003-01-01

    Anaerobic digestion is an appropriate technique for the treatment of sludge before final disposal and it is employed worldwide as the oldest and most important process for sludge stabilization. In general, mesophilic anaerobic digestion of sewage sludge is more widely used compared to thermophilic...... digestion. Furthermore, thermal pre-treatment is suitable for the improvement of stabilization, enhancement of dewatering of the sludge, reduction of the numbers of pathogens and could be realized at relatively low cost especially at low temperatures. The present study investigates (a) the differences...... between mesophilic and thermophilic anaerobic digestion of sludge and (b) the effect of the pretreatment at 70 degreesC on mesophilic and thermophilic anaerobic digestion of primary and secondary sludge. The pretreatment step showed very positive effect on the methane potential and production rate upon...

  2. A rigidifying salt-bridge favors the activity of thermophilic enzyme at high temperatures at the expense of low-temperature activity.

    Science.gov (United States)

    Lam, Sonia Y; Yeung, Rachel C Y; Yu, Tsz-Ha; Sze, Kong-Hung; Wong, Kam-Bo

    2011-03-01

    Thermophilic enzymes are often less active than their mesophilic homologues at low temperatures. One hypothesis to explain this observation is that the extra stabilizing interactions increase the rigidity of thermophilic enzymes and hence reduce their activity. Here we employed a thermophilic acylphosphatase from Pyrococcus horikoshii and its homologous mesophilic acylphosphatase from human as a model to study how local rigidity of an active-site residue affects the enzymatic activity. Acylphosphatases have a unique structural feature that its conserved active-site arginine residue forms a salt-bridge with the C-terminal carboxyl group only in thermophilic acylphosphatases, but not in mesophilic acylphosphatases. We perturbed the local rigidity of this active-site residue by removing the salt-bridge in the thermophilic acylphosphatase and by introducing the salt-bridge in the mesophilic homologue. The mutagenesis design was confirmed by x-ray crystallography. Removing the salt-bridge in the thermophilic enzyme lowered the activation energy that decreased the activation enthalpy and entropy. Conversely, the introduction of the salt-bridge to the mesophilic homologue increased the activation energy and resulted in increases in both activation enthalpy and entropy. Revealed by molecular dynamics simulations, the unrestrained arginine residue can populate more rotamer conformations, and the loss of this conformational freedom upon the formation of transition state justified the observed reduction in activation entropy. Our results support the conclusion that restricting the active-site flexibility entropically favors the enzymatic activity at high temperatures. However, the accompanying enthalpy-entropy compensation leads to a stronger temperature-dependency of the enzymatic activity, which explains the less active nature of the thermophilic enzymes at low temperatures.

  3. A rigidifying salt-bridge favors the activity of thermophilic enzyme at high temperatures at the expense of low-temperature activity.

    Directory of Open Access Journals (Sweden)

    Sonia Y Lam

    2011-03-01

    Full Text Available Thermophilic enzymes are often less active than their mesophilic homologues at low temperatures. One hypothesis to explain this observation is that the extra stabilizing interactions increase the rigidity of thermophilic enzymes and hence reduce their activity. Here we employed a thermophilic acylphosphatase from Pyrococcus horikoshii and its homologous mesophilic acylphosphatase from human as a model to study how local rigidity of an active-site residue affects the enzymatic activity.Acylphosphatases have a unique structural feature that its conserved active-site arginine residue forms a salt-bridge with the C-terminal carboxyl group only in thermophilic acylphosphatases, but not in mesophilic acylphosphatases. We perturbed the local rigidity of this active-site residue by removing the salt-bridge in the thermophilic acylphosphatase and by introducing the salt-bridge in the mesophilic homologue. The mutagenesis design was confirmed by x-ray crystallography. Removing the salt-bridge in the thermophilic enzyme lowered the activation energy that decreased the activation enthalpy and entropy. Conversely, the introduction of the salt-bridge to the mesophilic homologue increased the activation energy and resulted in increases in both activation enthalpy and entropy. Revealed by molecular dynamics simulations, the unrestrained arginine residue can populate more rotamer conformations, and the loss of this conformational freedom upon the formation of transition state justified the observed reduction in activation entropy.Our results support the conclusion that restricting the active-site flexibility entropically favors the enzymatic activity at high temperatures. However, the accompanying enthalpy-entropy compensation leads to a stronger temperature-dependency of the enzymatic activity, which explains the less active nature of the thermophilic enzymes at low temperatures.

  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. Effects of selected thermophilic microorganisms on crude oils at elevated temperatures and pressures. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Premuzic, E.T.; Lin, M.S.

    1995-07-01

    During the past several years, a considerable amount of work has been carried out showing that microbially enhanced oil recovery (MEOR) is promising and the resulting biotechnology may be deliverable. At the Brookhaven National Laboratory (BNL), systematic studies have been conducted which dealt with the effects of thermophilic and thermoadapted bacteria on the chemical and physical properties of selected types of crude oils at elevated temperatures and pressures. Particular attention was paid to heavy crude oils from Venezuela, California, Alabama, Arkansas, Wyoming, Alaska, and other oil producing areas. Current studies indicate that during the biotreatment several chemical and physical properties of crude oils are affected. The oils are (1) emulsified; (2) acidified; (3) there is a qualitative and quantitative change in light and heavy fractions of the crudes; (4) there are chemical changes in fractions containing sulfur compounds; (5) there is an apparent reduction in the concentration of trace metals; (6) the qualitative and quantitative changes appear to be microbial species dependent; and (7) there is a distinction between {open_quotes}biodegraded{close_quotes} and {open_quotes}biotreated{close_quotes} oils. Preliminary results indicate the introduced microorganisms may become the dominant species in the bioconversion of oils. These studies also indicate the biochemical interactions between crude oils and microorganisms follow distinct trends, characterized by a group of chemical markers. Core-flooding experiments have shown significant additional crude oil recoveries are achievable with thermophilic microorganisms at elevated temperatures similar to those found in oil reservoirs. In addition, the biochemical treatment of crude oils has technological applications in downstream processing of crude oils such as in upgrading of low grade oils and the production of hydrocarbon based detergents.

  6. Temperature and pH optima of enzyme activities produced by cellulolytic thermophilic fungi in batch and solid-state cultures

    Energy Technology Data Exchange (ETDEWEB)

    Grajek, W

    1986-01-01

    The temperature and pH optima of cellulolytic activities produced by thermophilic fungi in liquid and solid-state cultures were established. Some differences in optimal conditions for enzyme activities, which depended on culture methods, were confirmed. 10 references.

  7. Effects of Mesophilic and Thermophilic Temperature Condition to Biogas Production (Methane from Palm Oil Mill Effluent (POME with Cow Manures

    Directory of Open Access Journals (Sweden)

    Muhammad Fajar Fajar

    2018-01-01

    Full Text Available Biogas is an environmentally friendly renewable energy source. Biogas can be used using Palm Oil Mill Effluents (POME. However, the % yield of biogas productivity is still not optimum due to the low conversion. The biogas productivity can be optimized by adding methanogen bacteria which increase the methane production through the anaerobic fermentation process. This study aims to utilize cow manures as the source of methanogen bacteria in methane production from POME. Furthermore, this study specifically aims to obtain the optimum productivity condition of biogas production by the composition ratio of POME and cow manures to the amount of fermentation time at 35oC and 50oC for mesophilic and thermophilic bacteria, respectively. The ratio of POME and cow mature were A1 (100:0, A2 (80:20, A3 (70:30, A4 (60:40, and A5 (0:100. The highest yield of biogas production was A2 ratio using the thermophilic condition which showed 51.33% mol with the total solid decline of 73.43%, COD removal of 77.01%, and BOD removal of 70.02%.

  8. Thermophilic nitrate-reducing microorganisms prevent sulfate reduction in cold marine sediments incubated at high temperature

    Science.gov (United States)

    Nepomnyashchaya, Yana; Rezende, Julia; Hubert, Casey

    2014-05-01

    Hydrogen sulphide produced during metabolism of sulphate-reducing microorganisms (SRM) is toxic, corrosive and causes detrimental oil reservoir souring. During secondary oil recovery, injecting oil reservoirs with seawater that is rich in sulphate and that also cools high temperature formations provides favourable growth conditions for SRM. Nitrate addition can prevent metabolism of SRM by stimulating nitrate-reducing microorganisms (NRM). The investigations of thermophilic NRM are needed to develop mechanisms to control the metabolism of SRM in high temperature oil field ecosystems. We therefore established a model system consisting of enrichment cultures of cold surface marine sediments from the Baltic Sea (Aarhus Bay) that were incubated at 60°C. Enrichments contained 25 mM nitrate and 40 mM sulphate as potential electron acceptors, and a mixture of the organic substrates acetate, lactate, propionate, butyrate (5 mM each) and yeast extract (0.01%) as potential carbon sources and electron donors. Slurries were incubated at 60°C both with and without initial pasteurization at 80°C for 2 hours. In the enrichments containing both nitrate and sulphate, the concentration of nitrate decreased indicating metabolic activity of NRM. After a four-hour lag phase the rate of nitrate reduction increased and the concentration of nitrate dropped to zero after 10 hours of incubation. The concentration of nitrite increased as the reduction of nitrate progressed and reached 16.3 mM after 12 hours, before being consumed and falling to 4.4 mM after 19-day of incubation. No evidence for sulphate reduction was observed in these cultures during the 19-day incubation period. In contrast, the concentration of sulphate decreased up to 50% after one week incubation in controls containing only sulphate but no nitrate. Similar sulfate reduction rates were seen in the pasteurized controls suggesting the presence of heat resistant SRM, whereas nitrate reduction rates were lower in the

  9. Optimum Temperature for Storage of Fruit and Vegetables with Reference to Chilling Injury

    Science.gov (United States)

    Murata, Takao

    Cold storage is an important technique for preserving fresh fruit and vegetables. Deterioration due to ripening, senescence and microbiological disease can be retarded by storage at optimum temperature being slightly above the freezing point of tissues of fruit and vegetables. However, some fruit and vegetables having their origins in tropical or subtropical regions of the world are subject to chilling injury during transportation, storage and wholesale distribution at low temperature above freezing point, because they are usually sensitive to low temperature in the range of 15&digC to 0°C. This review will focus on the recent informations regarding chilling injury of fruit and vegetables, and summarize the optimum temperature for transportation and storage of fruit and vegetables in relation to chilling injury.

  10. Computational design and characterization of a temperature-sensitive plasmid replicon for gram positive thermophiles

    Directory of Open Access Journals (Sweden)

    Olson Daniel G

    2012-05-01

    Full Text Available Abstract Background Temperature-sensitive (Ts plasmids are useful tools for genetic engineering, but there are currently none compatible with the gram positive, thermophilic, obligate anaerobe, Clostridium thermocellum. Traditional mutagenesis techniques yield Ts mutants at a low frequency, and therefore requires the development of high-throughput screening protocols, which are also not available for this organism. Recently there has been progress in the development of computer algorithms which can predict Ts mutations. Most plasmids currently used for genetic modification of C. thermocellum are based on the replicon of plasmid pNW33N, which replicates using the RepB replication protein. To address this problem, we set out to create a Ts plasmid by mutating the gene coding for the RepB replication protein using an algorithm designed by Varadarajan et al. (1996 for predicting Ts mutants based on the amino-acid sequence of the protein. Results A library of 34 mutant plasmids was designed, synthesized and screened, resulting in 6 mutants which exhibited a Ts phenotype. Of these 6, the one with the most temperature-sensitive phenotype (M166A was compared with the original plasmid. It exhibited lower stability at 48°C and was completely unable to replicate at 55°C. Conclusions The plasmid described in this work could be useful in future efforts to genetically engineer C. thermocellum, and the method used to generate this plasmid may be useful for others trying to make Ts plasmids.

  11. Optimum Temperatures for Net Primary Productivity of Three Tropical Seagrass Species

    OpenAIRE

    Collier, Catherine J.; Ow, Yan X.; Langlois, Lucas; Uthicke, Sven; Johansson, Charlotte L.; O'Brien, Katherine R.; Hrebien, Victoria; Adams, Matthew P.

    2017-01-01

    Rising sea water temperature will play a significant role in responses of the world's seagrass meadows to climate change. In this study, we investigated seasonal and latitudinal variation (spanning more than 1,500 km) in seagrass productivity, and the optimum temperatures at which maximum photosynthesis and net productivity (for the leaf and the whole plant) occurs, for three seagrass species (Cymodocea serrulata, Halodule uninervis, and Zostera muelleri). To obtain whole plant net production...

  12. Continuous Hydrogen Production from Agricultural Wastewaters at Thermophilic and Hyperthermophilic Temperatures.

    Science.gov (United States)

    Ramos, Lucas Rodrigues; Silva, Edson Luiz

    2017-06-01

    The objective of this study was to investigate the effects of hydraulic retention time (HRT) (8 to 0.5 h) and temperature (55 to 75 °C) in two anaerobic fluidized bed reactors (AFBR) using cheese whey (AFBR-CW = 10,000 mg sugars L -1 ) and vinasse (AFBR-V = 10,000 mg COD L -1 ) as substrates. Decreasing the HRT to 0.5 h increased the hydrogen production rates in both reactors, with maximum values of 5.36 ± 0.81 L H 2 h -1 L -1 in AFBR-CW and 0.71 ± 0.16 L H 2 h -1 L -1 in AFBR-V. The optimal conditions for hydrogen production were the HRT of 4 h and temperature of 65 °C in AFBR-CW, observing maximum hydrogen yield (HY) of 5.51 ± 0.37 mmol H 2 g COD -1 . Still, the maximum HY in AFBR-V was 1.64 ± 0.22 mmol H 2 g COD -1 at 4 h and 55 °C. However, increasing the temperature to 75 °C reduced the hydrogen production in both reactors. Methanol and butyric, acetic, and lactic acids were the main metabolites at temperatures of 55 and 65 °C, favoring the butyric and acetic metabolic pathways of hydrogen production. The increased productions of lactate, propionate, and methanol at 75 °C indicate that the hydrogen-producing bacteria in the thermophilic inoculum were inhibited under hyperthermophilic conditions.

  13. Confidence interval of intrinsic optimum temperature estimated using thermodynamic SSI model

    Institute of Scientific and Technical Information of China (English)

    Takaya Ikemoto; Issei Kurahashi; Pei-Jian Shi

    2013-01-01

    The intrinsic optimum temperature for the development of ectotherms is one of the most important factors not only for their physiological processes but also for ecological and evolutional processes.The Sharpe-Schoolfield-Ikemoto (SSI) model succeeded in defining the temperature that can thermodynamically meet the condition that at a particular temperature the probability of an active enzyme reaching its maximum activity is realized.Previously,an algorithm was developed by Ikemoto (Tropical malaria does not mean hot environments.Journal of Medical Entomology,45,963-969) to estimate model parameters,but that program was computationally very time consuming.Now,investigators can use the SSI model more easily because a full automatic computer program was designed by Shi et al.(A modified program for estimating the parameters of the SSI model.Environmental Entomology,40,462-469).However,the statistical significance of the point estimate of the intrinsic optimum temperature for each ectotherm has not yet been determined.Here,we provided a new method for calculating the confidence interval of the estimated intrinsic optimum temperature by modifying the approximate bootstrap confidence intervals method.For this purpose,it was necessary to develop a new program for a faster estimation of the parameters in the SSI model,which we have also done.

  14. Physiology of thermophilic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Ljungdahl, L G

    1979-01-01

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

  15. Study on the optimum PCM melting temperature for energy savings in residential buildings worldwide

    Science.gov (United States)

    Saffari, M.; de Gracia, A.; Fernández, C.; Zsembinszki, G.; Cabeza, L. F.

    2017-10-01

    To maintain comfort conditions in residential buildings along a full year period, the use of active systems is generally required to either supply heating or cooling. The heating and cooling demands strongly depend on the climatic conditions, type of building and occupants’ behaviour. The overall annual energy consumption of the building can be reduced by the use of renewable energy sources and/or passive systems. The use of phase change materials (PCM) as passive systems in buildings enhances the thermal mass of the envelope, and reduces the indoor temperature fluctuations. As a consequence, the overall energy consumption of the building is generally lower as compared to the case when no PCM systems are used. The selection of the PCM melting temperature is a key issue to reduce the energy consumption of the buildings. The main focus of this study is to determine the optimum PCM melting temperature for passive heating and cooling according to different weather conditions. To achieve that, numerical simulations were carried out using EnergyPlus v8.4 coupled with GenOpt® v3.1.1 (a generic optimization software). A multi-family residential apartment was selected from ASHRAE Standard 90.1- 2013 prototype building model, and different climate conditions were considered to determine the optimum melting temperature (in the range from 20ºC to 26ºC) of the PCM contained in gypsum panels. The results confirm that the optimum melting temperature of the PCM strongly depends on the climatic conditions. In general, in cooling dominant climates the optimum PCM temperature is around 26ºC, while in heating dominant climates it is around 20ºC. Furthermore, the results show that an adequate selection of the PCM as passive system in building envelope can provide important energy savings for both heating dominant and cooling dominant regions.

  16. Endangerment of thermophilous flora even under conditions of increasing environmental temperatures

    Directory of Open Access Journals (Sweden)

    Vladimír Růžička

    2004-01-01

    Full Text Available As mentioned earlier, it is not true that some bulbous species from the family Orchidaceae are able to survive only mycotrophically, i. e. without formation of stalk. Our observations, especially of Ophrys apifera, have demonstrated (in the Czech Republic that the durability of adult plants is very short so that their numbers are fluctuating. The dying can be caused by several factors. Frost damages followed by rotting of underground parts (roots and bulbs are relatively frequent. The leaf rosette, which is the most resistant, dies as the last, usually later in the spring of the following year. This means that the frost damage is often not identified during the cursory visually control in the spring. We observated very extensive damaging and dying of the Orchidaceae after the winter of 2002/03 - on the turn of November and December 2002, there was a rapid onset of very strong black frost after a long, wet and relatively mild autumn. Consequently 80% of population perished. None specimens of Ophrys apifera and/or Himantoglossum adriaticum came into blossom in 2003 and other species were strongly damaged. Our observations document that the general increase in air temperatures need not result in the occurrence of generally expected better growing conditions for some thermophilous species. It is very probable that the extremes climatic conditions could show greater effects than the general increase in average temperatures. Such phenomena are well-known but in practice they are not noticed and/or are explained in a different way. Such risks can exist in the whole Central European region. Negative effects of frosts in winter 2002/03 were further intensified by long and extreme droughts in the growing season of the year 2003. Combination of these extremes was crucial for the species Gentianella bohemica: In average, 95% of specimens in each population perished. If the fluctuations in climatic conditions will be more frequent, some species can become

  17. Effect of temperature and temperature fluctuation on thermophilic anaerobic digestion of cattle manure.

    Science.gov (United States)

    El-Mashad, Hamed M; Zeeman, Grietje; van Loon, Wilko K P; Bot, Gerard P A; Lettinga, Gatze

    2004-11-01

    The influence of temperature, 50 and 60 degrees C, at hydraulic retention times (HRTs) of 20 and 10 days, on the performance of anaerobic digestion of cow manure has been investigated in completely stirred tank reactors (CSTRs). Furthermore, the effect of both daily downward and daily upward temperature fluctuations has been studied. In the daily downward temperature fluctuation regime the temperatures of each reactor was reduced by 10 degrees C for 10 h while in the daily upward fluctuation regime the temperature of each reactor was increased 10 degrees C for 5 h. The results show that the methane production rate at 60 degrees C is lower than that at 50 degrees C at all experimental conditions of imposed HRT except when downward temperature fluctuations were applied at an HRT of 10 days. It also was found that the free ammonia concentration not only affects the acetate-utilising bacteria but also the hydrolysis and acidification process. The upward temperature fluctuation affects the maximum specific methanogenesis activity more severely as compared to imposed downward temperature fluctuations. The results clearly reveal the possibility of using available solar energy at daytime to heat up the reactor(s) without the need of heat storage during nights, especially at an operational temperature of 50 degrees C and at a 20 days HRT, and without the jeopardising of the overheating.

  18. Effect of temperature and temperature fluctuation on thermophilic anaerobic digestion of cattle manure

    Energy Technology Data Exchange (ETDEWEB)

    El-Mashad, H.M. [Mansoura University, El-Mansoura (Egypt). Faculty of Agriculture, Department of Agricultural Engineering; Zeeman, G.; Van Loon, W.K.P.; Bot, G.P.A.; Lettinga, G. [Wageningen University Agrotechnion (Netherlands). Department of Agrotechnology and Food Sciences

    2004-11-01

    The influence of temperature, 50 and 60 {sup o}C, at hydraulic retention times (HRTs) of 20 and 10 days, on the performance of anaerobic digestion of cow manure has been investigated in completely stirred tank reactors (CSTRs). Furthermore, the effect of both daily downward and daily upward temperature fluctuations has been studied. In the daily downward temperature fluctuation regime the temperatures of each reactor was reduced by 10 {sup o}C for 10 h while in the daily upward fluctuation regime the temperature of each reactor was increased 10 {sup o}C for 5 h. The results show that the methane production rate at 60 {sup o}C is lower than that at 50 {sup o}C at all experimental conditions of imposed HRT except when downward temperature fluctuations were applied at an HRT of 10 days. It also was found that the free ammonia concentration not only affects the acetate-utilising bacteria but also the hydrolysis and acidification process. The upward temperature fluctuation affects the maximum specific methanogenesis activity more severely as compared to imposed downward temperature fluctuations. The results clearly reveal the possibility of using available solar energy at daytime to heat up the reactor(s) without the need of heat storage during nights, especially at an operational temperature of 50 {sup o}C and at a 20 days HRT, and without the jeopardising of the overheating. (author)

  19. Effect of temperature and temperature fluctuation on thermophilic anaerobic digestion of cattle manure

    NARCIS (Netherlands)

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

    2004-01-01

    The influence of temperature, 50 and 60 °C, at hydraulic retention times (HRTs) of 20 and 10 days, on the performance of anaerobic digestion of cow manure has been investigated in completely stirred tank reactors (CSTRs). Furthermore, the effect of both daily downward and daily upward temperature

  20. Optimum Temperatures for Net Primary Productivity of Three Tropical Seagrass Species

    Directory of Open Access Journals (Sweden)

    Catherine J. Collier

    2017-08-01

    Full Text Available Rising sea water temperature will play a significant role in responses of the world's seagrass meadows to climate change. In this study, we investigated seasonal and latitudinal variation (spanning more than 1,500 km in seagrass productivity, and the optimum temperatures at which maximum photosynthesis and net productivity (for the leaf and the whole plant occurs, for three seagrass species (Cymodocea serrulata, Halodule uninervis, and Zostera muelleri. To obtain whole plant net production, photosynthesis, and respiration rates of leaves and the root/rhizome complex were measured using oxygen-sensitive optodes in closed incubation chambers at temperatures ranging from 15 to 43°C. The temperature-dependence of photosynthesis and respiration was fitted to empirical models to obtain maximum metabolic rates and thermal optima. The thermal optimum (Topt for gross photosynthesis of Z. muelleri, which is more commonly distributed in sub-tropical to temperate regions, was 31°C. The Topt for photosynthesis of the tropical species, H. uninervis and C. serrulata, was considerably higher (35°C on average. This suggests that seagrass species are adapted to water temperature within their distributional range; however, when comparing among latitudes and seasons, thermal optima within a species showed limited acclimation to ambient water temperature (Topt varied by 1°C in C. serrulata and 2°C in H. uninervis, and the variation did not follow changes in ambient water temperature. The Topt for gross photosynthesis were higher than Topt calculated from plant net productivity, which includes above- and below-ground respiration for Z. muelleri (24°C and H. uninervis (33°C, but remained unchanged at 35°C in C. serrulata. Both estimated plant net productivity and Topt are sensitive to the proportion of below-ground biomass, highlighting the need for consideration of below- to above-ground biomass ratios when applying thermal optima to other meadows. The

  1. Optimum Temperatures for Net Primary Productivity of Three Tropical Seagrass Species.

    Science.gov (United States)

    Collier, Catherine J; Ow, Yan X; Langlois, Lucas; Uthicke, Sven; Johansson, Charlotte L; O'Brien, Katherine R; Hrebien, Victoria; Adams, Matthew P

    2017-01-01

    Rising sea water temperature will play a significant role in responses of the world's seagrass meadows to climate change. In this study, we investigated seasonal and latitudinal variation (spanning more than 1,500 km) in seagrass productivity, and the optimum temperatures at which maximum photosynthesis and net productivity (for the leaf and the whole plant) occurs, for three seagrass species ( Cymodocea serrulata, Halodule uninervis , and Zostera muelleri ). To obtain whole plant net production, photosynthesis, and respiration rates of leaves and the root/rhizome complex were measured using oxygen-sensitive optodes in closed incubation chambers at temperatures ranging from 15 to 43°C. The temperature-dependence of photosynthesis and respiration was fitted to empirical models to obtain maximum metabolic rates and thermal optima. The thermal optimum ( T opt ) for gross photosynthesis of Z. muelleri , which is more commonly distributed in sub-tropical to temperate regions, was 31°C. The T opt for photosynthesis of the tropical species, H. uninervis and C. serrulata , was considerably higher (35°C on average). This suggests that seagrass species are adapted to water temperature within their distributional range; however, when comparing among latitudes and seasons, thermal optima within a species showed limited acclimation to ambient water temperature ( T opt varied by 1°C in C. serrulata and 2°C in H. uninervis , and the variation did not follow changes in ambient water temperature). The T opt for gross photosynthesis were higher than T opt calculated from plant net productivity, which includes above- and below-ground respiration for Z. muelleri (24°C) and H. uninervis ( 33°C), but remained unchanged at 35°C in C. serrulata . Both estimated plant net productivity and T opt are sensitive to the proportion of below-ground biomass, highlighting the need for consideration of below- to above-ground biomass ratios when applying thermal optima to other meadows. The

  2. Growth characteristics of selected thermophilic strains of cyanobacteria using crossed gradients of temperature and light

    Czech Academy of Sciences Publication Activity Database

    Hindák, F.; Kvíderová, Jana; Lukavský, Jaromír

    2013-01-01

    Roč. 68, č. 5 (2013), s. 830-837 ISSN 0006-3088 R&D Projects: GA TA ČR TE01020080 Institutional support: RVO:67985939 Keywords : cyanobacteria * thermophiles * growth characteristics Subject RIV: EI - Biotechnology ; Bionics Impact factor: 0.696, year: 2013

  3. Critical isothermal temperature and optimum mechanical behaviour of high Si-containing bainitic steels

    International Nuclear Information System (INIS)

    Misra, A.; Sharma, S.; Sangal, S.; Upadhyaya, A.; Mondal, K.

    2012-01-01

    The redistribution of carbon during partitioning between retained austenite and bainitic ferrite decides the stability of the retained austenite. The martensitic start temperature (M S ) based on the carbon enriched retained austenite is observed to be the deciding factor for the volume fraction of the constituent phases obtained on isothermal bainitic transformation. The volume fraction of the phases is also calculated on the basis of metastable equi-free energy (T 0 ) curve. A good agreement is found between experimentally and theoretically calculated fractions of the phases. The isothermal holding temperature and time, the fraction of phases based on initial carbon content of the steel and M S temperatures have a close relation with the optimum mechanical properties of bainitic steels.

  4. Critical isothermal temperature and optimum mechanical behaviour of high Si-containing bainitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Misra, A.; Sharma, S.; Sangal, S.; Upadhyaya, A. [Department of Materials Science and Engineering, Indian Institute of Technology, Kanpur 208016 (India); Mondal, K., E-mail: kallol@iitk.ac.in [Department of Materials Science and Engineering, Indian Institute of Technology, Kanpur 208016 (India)

    2012-12-15

    The redistribution of carbon during partitioning between retained austenite and bainitic ferrite decides the stability of the retained austenite. The martensitic start temperature (M{sub S}) based on the carbon enriched retained austenite is observed to be the deciding factor for the volume fraction of the constituent phases obtained on isothermal bainitic transformation. The volume fraction of the phases is also calculated on the basis of metastable equi-free energy (T{sub 0}) curve. A good agreement is found between experimentally and theoretically calculated fractions of the phases. The isothermal holding temperature and time, the fraction of phases based on initial carbon content of the steel and M{sub S} temperatures have a close relation with the optimum mechanical properties of bainitic steels.

  5. Biohydrogen production from pig slurry in a CSTR reactor system with mixed cultures under hyper-thermophilic temperature (70 oC)

    International Nuclear Information System (INIS)

    Kotsopoulos, Thomas A.; Fotidis, Ioannis A.; Tsolakis, Nikolaos; Martzopoulos, Gerassimos G.

    2009-01-01

    A continuous stirred tank reactor (CSTR) (750 cm 3 working volume) was operated with pig slurry under hyper-thermophilic (70 o C) temperature for hydrogen production. The hydraulic retention time (HRT) was 24 h and the organic loading rate was 24.9 g d -1 of volatile solid (VS). The inoculum used in the hyper-thermophilic reactor was sludge obtained from a mesophilic methanogenic reactor. The continuous feeding with active biomass (inoculum) from the mesophilic methanogenic reactor was necessary in order to achieve hydrogen production. The hyper-thermophilic reactor started to produce hydrogen after a short adapted period of 4 days. During the steady state period the mean hydrogen yield was 3.65 cm 3 g -1 of volatile solid added. The high operation temperature of the reactor enhanced the hydrolytic activity in pig slurry and increased the volatile fatty acids (VFA) production. The short HRT (24 h) and the hyper-thermophilic temperature applied in the reactor were enough to prevent methanogenesis. No pre-treatment methods or other control methods for preventing methanogenesis were necessary. Hyper-thermophilic hydrogen production was demonstrated for the first time in a CSTR system, fed with pig slurry, using mixed culture. The results indicate that this system is a promising one for biohydrogen production from pig slurry.

  6. Comparison of the microbial communities in solid-state anaerobic digestion (SS-AD) reactors operated at mesophilic and thermophilic temperatures.

    Science.gov (United States)

    Li, Yueh-Fen; Nelson, Michael C; Chen, Po-Hsu; Graf, Joerg; Li, Yebo; Yu, Zhongtang

    2015-01-01

    The microbiomes involved in liquid anaerobic digestion process have been investigated extensively, but the microbiomes underpinning solid-state anaerobic digestion (SS-AD) are poorly understood. In this study, microbiome composition and temporal succession in batch SS-AD reactors, operated at mesophilic or thermophilic temperatures, were investigated using Illumina sequencing of 16S rRNA gene amplicons. A greater microbial richness and evenness were found in the mesophilic than in the thermophilic SS-AD reactors. Firmicutes accounted for 60 and 82 % of the total Bacteria in the mesophilic and in the thermophilic SS-AD reactors, respectively. The genus Methanothermobacter dominated the Archaea in the thermophilic SS-AD reactors, while Methanoculleus predominated in the mesophilic SS-AD reactors. Interestingly, the data suggest syntrophic acetate oxidation coupled with hydrogenotrophic methanogenesis as an important pathway for biogas production during the thermophilic SS-AD. Canonical correspondence analysis (CCA) showed that temperature was the most influential factor in shaping the microbiomes in the SS-AD reactors. Thermotogae showed strong positive correlation with operation temperature, while Fibrobacteres, Lentisphaerae, Spirochaetes, and Tenericutes were positively correlated with daily biogas yield. This study provided new insight into the microbiome that drives SS-AD process, and the findings may help advance understanding of the microbiome in SS-AD reactors and the design and operation of SS-AD systems.

  7. Establishment of thermophilic anaerobic terephthalic acid degradation system through one-step temperature increase startup strategy - Revealed by Illumina Miseq Sequencing.

    Science.gov (United States)

    Ma, Kai-Li; Li, Xiang-Kun; Wang, Ke; Meng, Ling-Wei; Liu, Gai-Ge; Zhang, Jie

    2017-10-01

    Over recent years, thermophilic digestion was constantly focused owing to its various advantage over mesophilic digestion. Notably, the startup approach of thermophilic digester needs to be seriously considered as unsuitable startup ways may result in system inefficiency. In this study, one-step temperature increase startup strategy from 37 °C to 55 °C was applied to establish a thermophilic anaerobic system treating terephthalic acid (TA) contained wastewater, meanwhile, the archaeal and bacterial community compositions at steady periods of 37 °C and 55 °C during the experimental process was also compared using Illumina Miseq Sequencing. The process operation demonstrated that the thermophilic TA degradation system was successfully established at 55 °C with over 95% COD reduction. For archaea community, the elevation of operational temperature from 37 °C to 55 °C accordingly increase the enrichment of hydrogenotrophic methanogens but decrease the abundance of the acetotrophic ones. While for bacterial community, the taxonomic analysis suggested that Syntrophorhabdus (27.40%) was the dominant genus promoting the efficient TA degradation under mesophilic condition, whereas OPB95 (24.99%) and TA06 (14.01%) related populations were largely observed and probably take some crucial role in TA degradation under thermophilic condition. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Climate applications for NOAA 1/4° Daily Optimum Interpolation Sea Surface Temperature

    Science.gov (United States)

    Boyer, T.; Banzon, P. V. F.; Liu, G.; Saha, K.; Wilson, C.; Stachniewicz, J. S.

    2015-12-01

    Few sea surface temperature (SST) datasets from satellites have the long temporal span needed for climate studies. The NOAA Daily Optimum Interpolation Sea Surface Temperature (DOISST) on a 1/4° grid, produced at National Centers for Environmental Information, is based primarily on SSTs from the Advanced Very High Resolution Radiometer (AVHRR), available from 1981 to the present. AVHRR data can contain biases, particularly when aerosols are present. Over the three decade span, the largest departure of AVHRR SSTs from buoy temperatures occurred during the Mt Pinatubo and El Chichon eruptions. Therefore, in DOISST, AVHRR SSTs are bias-adjusted to match in situ SSTs prior to interpolation. This produces a consistent time series of complete SST fields that is suitable for modelling and investigating local climate phenomena like El Nino or the Pacific warm blob in a long term context. Because many biological processes and animal distributions are temperature dependent, there are also many ecological uses of DOISST (e.g., coral bleaching thermal stress, fish and marine mammal distributions), thereby providing insights into resource management in a changing ocean. The advantages and limitations of using DOISST for different applications will be discussed.

  9. Novel immobilization process of a thermophilic catalase: efficient purification by heat treatment and subsequent immobilization at high temperature.

    Science.gov (United States)

    Xu, Juan; Luo, Hui; López, Claudia; Xiao, Jing; Chang, Yanhong

    2015-10-01

    The main goal of the present work is to investigate a novel process of purification and immobilization of a thermophilic catalase at high temperatures. The catalase, originated from Bacillus sp., was overexpressed in a recombinant Escherichia coli BL21(DE3)/pET28-CATHis and efficiently purified by heat treatment, achieving a threefold purification. The purified catalase was then immobilized onto an epoxy support at different temperatures (25, 40, and 55 °C). The immobilizate obtained at higher temperatures reached its maximum activity in a shorter time than that obtained at lower temperatures. Furthermore, immobilization at higher temperatures required a lower ionic strength than immobilization at lower temperatures. The characteristics of immobilized enzymes prepared at different temperatures were investigated. The high-temperature immobilizate (55 °C) showed the highest thermal stability, followed by the 40 °C immobilizate. And the high-temperature immobilizate (55 °C) had slightly higher operational stability than the 25 °C immobilizate. All of the immobilized catalase preparations showed higher stability than the free enzyme at alkaline pH 10.0, while the alkali resistance of the 25 °C immobilizate was slightly better than that of the 40 and 55 °C immobilizates.

  10. Status on Science and Application of Thermophilic Anaerobic Digestion

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær

    1994-01-01

    Thermophilic anaerobic processes are often regarded as less stable than mesophilic processes. In the paper this postulate is examined and disproved based on real operational data from of full-scale mesophilic and thermophilic biogas plants. The start-up produce for the thermophilic plants was...... for thermophilic digestion along with the implications for the methanogenic bacteria active at these temperatures....

  11. An experimental evaluation of energy economics of biogas production at mesophilic and thermophilic temperatures

    International Nuclear Information System (INIS)

    Ezeonu, F. C.

    1997-01-01

    Process economy, with regard to and energy content predicts the potentialities of biogas production options. Experimental study reveal from the kinetic data of daily biogas production that biomethanation reaction is faster in thermophilic digestion, with a higher yield of gas per reactor volume per day. Energy calculations show that it will take 3.55*10 5 kWh to produce 1 m 3 of methane from our feedstock with biogas energy equivalent of 1.25 kWh. The cost implication of this is enormous amounting to US $2,641.95 for the production of 1 m 3 of methane using brewers spent grins

  12. Optimum Performance Enhancing Strategies of the Gas Turbine Based on the Effective Temperatures

    Directory of Open Access Journals (Sweden)

    Ibrahim Thamir K.

    2016-01-01

    Full Text Available Gas turbines (GT have come to play a significant role in distributed energy systems due to its multi-fuel capability, compact size and low environmental impact and reduced cost. Nevertheless, the low electrical efficiency, typically about 30% (LHV, is an important obstruction to the development of the GT plants. New strategies are designed for the GT plant, to increase the overall performance based on the operational modeling and optimization of GT power plants. The enhancing strategies effect on the GT power plant’s performance (with intercooler, two-shaft, reheat and regenerative based on the real power plant of GT. An analysis based on thermodynamics has been carried out on the modifications of the cycle configurations’ enhancements. Then, the results showed the effect of the ambient and turbine inlet temperatures on the performance of the GT plants to select an optimum strategy for the GT. The performance model code to compare the strategies of the GT plants were developed utilizing the MATLAB software. The results show that, the best thermal efficiency occurs in the intercooler-regenerative-reheated GT strategy (IRHGT; it decreased from 51.5 to 48%, when the ambient temperature increased (from 273 to 327K. Furthermore, the thermal efficiency of the GT for the strategies without the regenerative increased (about 3.3%, while thermal efficiency for the strategies with regenerative increased (about 22% with increased of the turbine inlet temperature. The lower thermal efficiency occurs in the IHGT strategy, while the higher thermal efficiency occurs in the IRHGT strategy. However, the power output variation is more significant at a higher value of the turbine inlet temperature. The simulation model gives a consistent result compared with Baiji GT plant. The extensive modeling performed in this study reveals that; the ambient temperature and turbine inlet temperature are strongly influenced on the performance of GT plant.

  13. Determination of Optimum Viewing Angles for the Angular Normalization of Land Surface Temperature over Vegetated Surface

    Directory of Open Access Journals (Sweden)

    Huazhong Ren

    2015-03-01

    Full Text Available Multi-angular observation of land surface thermal radiation is considered to be a promising method of performing the angular normalization of land surface temperature (LST retrieved from remote sensing data. This paper focuses on an investigation of the minimum requirements of viewing angles to perform such normalizations on LST. The normally kernel-driven bi-directional reflectance distribution function (BRDF is first extended to the thermal infrared (TIR domain as TIR-BRDF model, and its uncertainty is shown to be less than 0.3 K when used to fit the hemispheric directional thermal radiation. A local optimum three-angle combination is found and verified using the TIR-BRDF model based on two patterns: the single-point pattern and the linear-array pattern. The TIR-BRDF is applied to an airborne multi-angular dataset to retrieve LST at nadir (Te-nadir from different viewing directions, and the results show that this model can obtain reliable Te-nadir from 3 to 4 directional observations with large angle intervals, thus corresponding to large temperature angular variations. The Te-nadir is generally larger than temperature of the slant direction, with a difference of approximately 0.5~2.0 K for vegetated pixels and up to several Kelvins for non-vegetated pixels. The findings of this paper will facilitate the future development of multi-angular thermal infrared sensors.

  14. Drivers of microbial community composition in mesophilic and thermophilic temperature-phased anaerobic digestion pre-treatment reactors.

    Science.gov (United States)

    Pervin, Hasina M; Dennis, Paul G; Lim, Hui J; Tyson, Gene W; Batstone, Damien J; Bond, Philip L

    2013-12-01

    Temperature-phased anaerobic digestion (TPAD) is an emerging technology that facilitates improved performance and pathogen destruction in anaerobic sewage sludge digestion by optimising conditions for 1) hydrolytic and acidogenic organisms in a first-stage/pre-treatment reactor and then 2) methogenic populations in a second stage reactor. Pre-treatment reactors are typically operated at 55-65 °C and as such select for thermophilic bacterial communities. However, details of key microbial populations in hydrolytic communities and links to functionality are very limited. In this study, experimental thermophilic pre-treatment (TP) and control mesophilic pre-treatment (MP) reactors were operated as first-stages of TPAD systems treating activated sludge for 340 days. The TP system was operated sequentially at 50, 60 and 65 °C, while the MP rector was held at 35 °C for the entire period. The composition of microbial communities associated with the MP and TP pre-treatment reactors was characterised weekly using terminal-restriction fragment length polymorphism (T-RFLP) supported by clone library sequencing of 16S rRNA gene amplicons. The outcomes of this approach were confirmed using 454 pyrosequencing of gene amplicons and fluorescence in-situ hybridisation (FISH). TP associated bacterial communities were dominated by populations affiliated to the Firmicutes, Thermotogae, Proteobacteria and Chloroflexi. In particular there was a progression from Thermotogae to Lutispora and Coprothermobacter and diversity decreased as temperature and hydrolysis performance increased. While change in the composition of TP associated bacterial communities was attributable to temperature, that of MP associated bacterial communities was related to the composition of the incoming feed. This study determined processes driving the dynamics of key microbial populations that are correlated with an enhanced hydrolytic functionality of the TPAD system. Copyright © 2013 Elsevier Ltd. All rights

  15. Biohydrogen production from household solid waste (HSW) at extreme-thermophilic temperature (70 degrees C) - Influence of pH and acetate concentration

    DEFF Research Database (Denmark)

    Liu, Dawei; Min, Booki; Angelidaki, Irini

    2008-01-01

    Hydrogen production from household solid waste (HSW) was performed via dark fermentation by using an extreme-thermophilic mixed culture, and the effect of pH and acetate on the biohydrogen production was investigated. The highest hydrogen production yield was 257 +/- 25 mL/gVS(added) at the optimum...... pH of 7.0. Acetate was proved to be inhibiting the dark fermentation process at neutral pH, which indicates that the inhibition was caused by total acetate concentration not by undissociated acetate. Initial inhibition was detected at acetate concentration of 50 mM, while the hydrogen fermentation...

  16. 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...

  17. Cellulolytic properties of an extremely thermophilic anaerobe

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, J A; Morgan, H W; Daniel, R M [Waikato Univ., Hamilton (New Zealand). Microbial Biochemistry and Biotechnology Unit

    1990-09-01

    An extremely thermophilic anaerobe was isolated from a New Zealand hot spring by incubating bacterial mat strands in a medium containing xylan. The Gramreaction-negative organism that was subsequently purified had a temperature optimum of 70deg C and a pH optimum of 7.0. The isolate, designated strain H173, grew on a restricted range of carbon sources. In batch culture H173 could degrade Avicel completely when supplied at 5 or 10 g l{sup -1}. There was an initial growth phase, during which a cellulase complex was produced and carbohydrates fermented to form acetic and lactic acids, followed by a phase where cells were not metabolising but the cellulase complex actively converted cellulose to glucose. When co-cultered with strain Rt8.B1, an ethanologenic extreme thermophile, glucose was fermented to ethanol and acetate, and no reducing sugars accumulated in the medium. In pH controlled batch culture H173 produced an increased amount of lactate and acetate but there was again a phase when reducing sugars accumulated in the medium, and these were converted to ethanol by co-culture with Rt8.B1. (orig.).

  18. Optimum electron temperature and density for short-wavelength plasma-lasing from nickel-like ions

    International Nuclear Information System (INIS)

    Masoudnia, Leili; Bleiner, Davide

    2014-01-01

    Soft X-ray lasing across a Ni-like plasma gain-medium requires optimum electron temperature and density for attaining to the Ni-like ion stage and for population inversion in the 3d 9 4d 1 (J=0)→3d 9 4p 1 (J=1) laser transition. Various scaling laws, function of operating parameters, were compared with respect to their predictions for optimum temperatures and densities. It is shown that the widely adopted local thermodynamic equilibrium (LTE) model underestimates the optimum plasma-lasing conditions. On the other hand, non-LTE models, especially when complemented with dielectronic recombination, provided accurate prediction of the optimum plasma-lasing conditions. It is further shown that, for targets with Z equal or greater than the rare-earth elements (e.g. Sm), the optimum electron density for plasma-lasing is not accessible for pump-pulses at λ=1ω=1μm. This observation explains a fundamental difficulty in saturating the wavelength of plasma-based X-ray lasers below 6.8 nm, unless using 2ω pumping

  19. Insights into high-temperature nitrogen cycling from studies of the thermophilic ammonia-oxidizing archaeon Nitrosocaldus yellowstonii. (Invited)

    Science.gov (United States)

    de la Torre, J. R.

    2010-12-01

    Our understanding of the nitrogen cycle has advanced significantly in recent years with the discovery of new metabolic processes and the recognition that key processes such as aerobic ammonia oxidation are more broadly distributed among extant organisms and habitat ranges. Nitrification, the oxidation of ammonia to nitrite and nitrate, is a key component of the nitrogen cycle and, until recently, was thought to be mediated exclusively by the ammonia-oxidizing bacteria (AOB). The discovery that mesophilic marine archaea, some of the most abundant microorganisms on the planet, are capable of oxidizing ammonia to nitrite fundamentally changed our perception of the global nitrogen cycle. Ammonia-oxidizing archaea (AOA) are now thought to be significant drivers of nitrification in many marine and terrestrial environments. Most studies, however, have focused on the contribution of AOA to nitrogen cycling in mesophilic environments. Our recent discovery of a thermophilic AOA, Nitrosocaldus yellowstonii, has expanded the role and habitat range of AOA to include high temperature environments. Numerous studies have shown that AOA are widely distributed in geothermal habitats with a wide range of temperature and pH. The availability of multiple AOA genome sequences, combined with metagenomic studies from mesophilic and thermophilic environments gives us a better understanding of the physiology, ecology and evolution of these organisms. Recent studies have proposed that the AOA represent the most deeply branching lineage within the Archaea, the Thaumarchaeota. Furthermore, genomic comparisons between AOA and AOB reveal significant differences in the proposed pathways for ammonia oxidation. These genetic differences likely explain fundamental physiological differences such as the resistance of N. yellowstonii and other AOA to the classical nitrification inhibitors allylthiourea and acetylene. Physiological studies suggest that the marine AOA are adapted to oligotrophic

  20. Determination of an optimum reactor coolant system average temperature within the licensed operating window

    International Nuclear Information System (INIS)

    Thaulez, F.; Basic, I.; Vrbanic, I.

    2003-01-01

    The Krsko modernization power uprate analyses have been performed in such a way as to cover plant operation in a range of average reactor coolant temperatures (Tavg) of 301.7 deg C to 307.4 deg C, with steam generator tube plugging levels of up to 5%. The upper bound is temporarily restricted to 305.7 deg C, as long as Zirc-4 fuel is present in the core. (It is, however,acceptable to operate at 307.4 deg C with a few Zirc-4 assemblies, if meeting certain conditionsand subjected to a corrosion and rod internal pressure evaluation in the frame of the cyclespecificnuclear core design.) The Tavg optimization method takes into account two effects, that are opposed to each other: the impact of steam pressure on the electrical power output versus the impact of Tavg on the cost of reactor fuel. The positive economical impact of a Tavg increase through the increase in MWe output is around 6 to 8 times higher than the corresponding negative impact on the fuel cost. From this perspective, it is desirable to have Tavg as high as possible. This statement is not affected by a change in the relationship between steam pressure and Tavg level. However, there are also other considerations intervening in the definition of the optimum. This paper discusses the procedure for selection of optimal Tavg for the forthcoming cycle in relation to the impacts of change in Tavg level and/or variations of the steam pressure versus Tavg relationship. (author)

  1. 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.

  2. Exogenous cellulases of thermophilic micromycetes. Pt. 2. Thermostability of enzyme preparations

    Energy Technology Data Exchange (ETDEWEB)

    Kvesitadze, G; Gogilashvili, L; Svanidze, R; Buachidze, T; Chirgadze, L; Nizharadze, D

    1986-01-01

    The ability of a large number of higher fungi to form extracellular cellulases is investigated. Some representatives of these fungi grow at 40-50/sup 0/C, and form extracellular cellulases exceeding cellulases of mesophilic fungi in thermostability. It is shown that cellulases of higher thermophilic fungi differ by their thermostability. The temperature optimum of cellulase action of higher fungi occurs within 60-62/sup 0/C.

  3. Prediction of the optimum hybridization conditions of dot-blot-SNP analysis using estimated melting temperature of oligonucleotide probes.

    Science.gov (United States)

    Shiokai, Sachiko; Kitashiba, Hiroyasu; Nishio, Takeshi

    2010-08-01

    Although the dot-blot-SNP technique is a simple cost-saving technique suitable for genotyping of many plant individuals, optimization of hybridization and washing conditions for each SNP marker requires much time and labor. For prediction of the optimum hybridization conditions for each probe, we compared T (m) values estimated from nucleotide sequences using the DINAMelt web server, measured T (m) values, and hybridization conditions yielding allele-specific signals. The estimated T (m) values were comparable to the measured T (m) values with small differences of less than 3 degrees C for most of the probes. There were differences of approximately 14 degrees C between the specific signal detection conditions and estimated T (m) values. Change of one level of SSC concentrations of 0.1, 0.2, 0.5, and 1.0x SSC corresponded to a difference of approximately 5 degrees C in optimum signal detection temperature. Increasing the sensitivity of signal detection by shortening the exposure time to X-ray film changed the optimum hybridization condition for specific signal detection. Addition of competitive oligonucleotides to the hybridization mixture increased the suitable hybridization conditions by 1.8. Based on these results, optimum hybridization conditions for newly produced dot-blot-SNP markers will become predictable.

  4. Extremely thermophilic microorganisms for biomass conversion: status and prospects.

    Science.gov (United States)

    Blumer-Schuette, Sara E; Kataeva, Irina; Westpheling, Janet; Adams, Michael Ww; Kelly, Robert M

    2008-06-01

    Many microorganisms that grow at elevated temperatures are able to utilize a variety of carbohydrates pertinent to the conversion of lignocellulosic biomass to bioenergy. The range of substrates utilized depends on growth temperature optimum and biotope. Hyperthermophilic marine archaea (T(opt)>or=80 degrees C) utilize alpha- and beta-linked glucans, such as starch, barley glucan, laminarin, and chitin, while hyperthermophilic marine bacteria (T(opt)>or=80 degrees C) utilize the same glucans as well as hemicellulose, such as xylans and mannans. However, none of these organisms are able to efficiently utilize crystalline cellulose. Among the thermophiles, this ability is limited to a few terrestrial bacteria with upper temperature limits for growth near 75 degrees C. Deconstruction of crystalline cellulose by these extreme thermophiles is achieved by 'free' primary cellulases, which are distinct from those typically associated with large multi-enzyme complexes known as cellulosomes. These primary cellulases also differ from the endoglucanases (referred to here as 'secondary cellulases') reported from marine hyperthermophiles that show only weak activity toward cellulose. Many extremely thermophilic enzymes implicated in the deconstruction of lignocellulose can be identified in genome sequences, and many more promising biocatalysts probably remain annotated as 'hypothetical proteins'. Characterization of these enzymes will require intensive effort but is likely to generate new opportunities for the use of renewable resources as biofuels.

  5. Thermophilic amylase from Thermus sp. isolation and its potential application for bioethanol production

    Directory of Open Access Journals (Sweden)

    Amin Fatoni

    2012-11-01

    Full Text Available Limited reserves of fossil energy stimulate researchers to explore for a new alternative energy, such as bioethanol.A thermophilic amylase producing bacterium was isolated from local hot-springs and its characteristic and potential applicationfor bioethanol production was determined. The obtained amylase was studied to determine its optimum temperature, pH,enzymatic reaction time, and substrate concentration. Tapioca waste was used as the substrate to find the potential of theamylase for degrading starch into glucose, and then the process was continued by fermentation to produce bioethanol. Theamylase producer bacterium was proposed as genus Thermus sp. The crude amylase that was obtained has the optimumtemperature of 60°C and optimum pH of 8.0, optimum substrate concentration at 10% (w/w and optimum enzymatic reactiontime of 45 minutes. These enzymes convert the starches of waste tapioca at optimum conditions, with the result of 2.9%ethanol produced from raw materials.

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

    NARCIS (Netherlands)

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

    2002-01-01

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

  7. Bypass valve and coolant flow controls for optimum temperatures in waste heat recovery systems

    Science.gov (United States)

    Meisner, Gregory P

    2013-10-08

    Implementing an optimized waste heat recovery system includes calculating a temperature and a rate of change in temperature of a heat exchanger of a waste heat recovery system, and predicting a temperature and a rate of change in temperature of a material flowing through a channel of the waste heat recovery system. Upon determining the rate of change in the temperature of the material is predicted to be higher than the rate of change in the temperature of the heat exchanger, the optimized waste heat recovery system calculates a valve position and timing for the channel that is configurable for achieving a rate of material flow that is determined to produce and maintain a defined threshold temperature of the heat exchanger, and actuates the valve according to the calculated valve position and calculated timing.

  8. Thermophilic Fungi: Their Physiology and Enzymes†

    OpenAIRE

    Maheshwari, Ramesh; Bharadwaj, Girish; Bhat, Mahalingeshwara K.

    2000-01-01

    Thermophilic fungi are a small assemblage in mycota that have a minimum temperature of growth at or above 20 degrees C and a maximum temperature of growth extending Itp to 60 to 62 degrees C. As the only representatives of eukaryotic organisms that can grow at temperatures above 45 degrees C, the thermophilic fungi are valuable experimental systems for investigations of mechanisms that allow growth at moderately high temperature yet limit their growth beyond 60 to 62 degrees C. Although wides...

  9. Temperature optimum of algae living in the outfall of a power plant on Lake Monona

    International Nuclear Information System (INIS)

    Brock, T.D.; Hoffmann, J.

    1974-01-01

    Temperature optima for photosynthesis were measured for algal populations living in the outfall of a fossil-fuel electric power plant on Lake Monona and were compared with the temperature optima of algae living in a control area in the nearby Yahara River. The temperature of the power plant outfall averaged about 8 0 C higher than that of the Yahara River. In the winter, no differences in species composition between the two study areas could be detected, Cladophora and Ulothrix being the dominant algae. The temperature optima of the populations from the two locations were the same, around 27 0 C, although the habitat temperatures at both locations were considerably lower. The only difference in response to temperature seen between the two populations was that the population at the outfall was able to photosynthesize at higher temperature, still showing high photosynthesis at 35 0 C and detectable photosynthesis at 46 0 C, a temperature at which the population from the Yahara River showed no detectable photosynthesis. In the summer, the dominant algae at the power plant outfall were Stigeoclonium and filamentous blue-green algae (family Oscillatoriaceae), whereas at the Yahara River the algal population was almost exclusively Cladophora. The temperature optima of both summer populations were the same, 31.5 0 C, only slightly higher than the mid-winter optima. Again, the population from the power plant was able to photosynthesize at higher temperature than the control population, showing quite active photosynthesis at 42.5 0 C, a temperature at which the population from the Yahara River was completely inactive. (U.S.)

  10. Evaluation of the Optimum Composition of Low-Temperature Fuel Cell Electrocatalysts for Methanol Oxidation by Combinatorial Screening.

    Science.gov (United States)

    Antolini, Ermete

    2017-02-13

    Combinatorial chemistry and high-throughput screening represent an innovative and rapid tool to prepare and evaluate a large number of new materials, saving time and expense for research and development. Considering that the activity and selectivity of catalysts depend on complex kinetic phenomena, making their development largely empirical in practice, they are prime candidates for combinatorial discovery and optimization. This review presents an overview of recent results of combinatorial screening of low-temperature fuel cell electrocatalysts for methanol oxidation. Optimum catalyst compositions obtained by combinatorial screening were compared with those of bulk catalysts, and the effect of the library geometry on the screening of catalyst composition is highlighted.

  11. Fossil palm beetles refine upland winter temperatures in the Early Eocene Climatic Optimum.

    Science.gov (United States)

    Archibald, S Bruce; Morse, Geoffrey E; Greenwood, David R; Mathewes, Rolf W

    2014-06-03

    Eocene climate and associated biotic patterns provide an analog system to understand their modern interactions. The relationship between mean annual temperatures and winter temperatures-temperature seasonality-may be an important factor in this dynamic. Fossils of frost-intolerant palms imply low Eocene temperature seasonality into high latitudes, constraining average winter temperatures there to >8 °C. However, their presence in a paleocommunity may be obscured by taphonomic and identification factors for macrofossils and pollen. We circumvented these problems by establishing the presence of obligate palm-feeding beetles (Chrysomelidae: Pachymerina) at three localities (a fourth, tentatively) in microthermal to lower mesothermal Early Eocene upland communities in Washington and British Columbia. This provides support for warmer winter Eocene climates extending northward into cooler Canadian uplands.

  12. High-temperature crystallization of the secondary alcohol dehydrogenase from the extreme thermophilic bacteria Thermoanaerobacter ethanolicus, a bifunctional alcohol dehydrogenase-acetyl-CoA thio esterase

    International Nuclear Information System (INIS)

    Watanabe, L.; Arni, R.K.

    1996-01-01

    Full text. Ethanol fermentations from Saccharomyces sp. are used in industrial ethanol production and are performed at mesophilic temperatures where final ethanol concentrations must exceed 4% (v/v) to make the process industrially economic. In addition, distillation is required to recover ethanol. Thermophilic fermentations are very attractive since they enable separation of ethanol from continuous cultures at process temperature and reduced pressure. Two different ethanol-production pathways have been identified for thermophilic bacteria; type I from Clostridium thermocellum, which contains only NADH-linked primary-alcohol dehydrogeneases, and type II from Thermoanaerobacter brockii which in addition include NADPH-linked secondary-alcohol dehydrogenases. The thermophilic anaerobic bacterium T ethanolicus 39E produces ethanol as the major end product from starch, pentose and herose substrates. The 2 Adh has a lower catalytic efficiency for the oxidation of 1 alcohols, including ethanol, than for the oxidation of secondary (2) alcohols or the reduction of ketones or aldehydes and possesses a significant acetyl-CoA reductive thioesterase activity. Large single crystals (0.7 x 0.3 x 0.3 mn) of this enzyme have been obtained at 40 0 C and diffraction data to 2.7 A resolution has been collected (R merge = 10.44%). Attempts are currently underway to obtain higher resolution data and a search for heavy atom derivatives is currently underway. The crystals belong to the space group P2 1 2 1 2 with cell constants of a a= 170.0 A, b=125.7 A and c=80.5 A. The asymmetric unit contains a tetramer as in the case of the crystals of the secondary alcohol dehydrogenase from Thermoanaerobacter brockii with a V M of 2.85 A 3 /Da. (author)

  13. Towards an optimum silicon heterojunction solar cell configuration for high temperature and high light intensity environment

    KAUST Repository

    Abdallah, Amir

    2017-09-22

    We report on the performance of Silicon Heterojunction (SHJ) solar cell under high operating temperature and varying irradiance conditions typical to desert environment. In order to define the best solar cell configuration that resist high operating temperature conditions, two different intrinsic passivation layers were tested, namely, an intrinsic amorphous silicon a-SiO:H with CO/SiH ratio of 0.4 and a-SiOx:H with CO/SiH ratio of 0.8, and the obtained performance were compared with those of a standard SHJ cell configuration having a-Si:H passivation layer. Our results showed how the short circuit current density J, and fill factor FF temperature-dependency are impacted by the cell\\'s configuration. While the short circuit current density J for cells with a-SiO:H layers was found to improve as compared with that of standard a-Si:H layer, introducing the intrinsic amorphous silicon oxide (a-SiO:H) layer with CO/SiH ratio of 0.8 has resulted in a reduction of the FF at room temperature due to hindering the carrier transport by the band structure. Besides, this FF was found to improve as the temperature increases from 15 to 45°C, thus, a positive FF temperature coefficient.

  14. Towards an optimum silicon heterojunction solar cell configuration for high temperature and high light intensity environment

    KAUST Repository

    Abdallah, Amir; Daif, Ounsi El; Aï ssa, Brahim; Kivambe, Maulid; Tabet, Nouar; Seif, Johannes; Haschke, Jan; Cattin, Jean; Boccard, Mathieu; De Wolf, Stefaan; Ballif, Christophe

    2017-01-01

    We report on the performance of Silicon Heterojunction (SHJ) solar cell under high operating temperature and varying irradiance conditions typical to desert environment. In order to define the best solar cell configuration that resist high operating temperature conditions, two different intrinsic passivation layers were tested, namely, an intrinsic amorphous silicon a-SiO:H with CO/SiH ratio of 0.4 and a-SiOx:H with CO/SiH ratio of 0.8, and the obtained performance were compared with those of a standard SHJ cell configuration having a-Si:H passivation layer. Our results showed how the short circuit current density J, and fill factor FF temperature-dependency are impacted by the cell's configuration. While the short circuit current density J for cells with a-SiO:H layers was found to improve as compared with that of standard a-Si:H layer, introducing the intrinsic amorphous silicon oxide (a-SiO:H) layer with CO/SiH ratio of 0.8 has resulted in a reduction of the FF at room temperature due to hindering the carrier transport by the band structure. Besides, this FF was found to improve as the temperature increases from 15 to 45°C, thus, a positive FF temperature coefficient.

  15. Noise and optimum filtering in spectrometers with semiconductor detectors operating at elevated temperature

    International Nuclear Information System (INIS)

    Dabrowski, W.; Korbel, K.

    1983-01-01

    The importance of the excess noise in the semiconductor detectors operating at the elevated temperature is discussed. Under the assumption of a conventional CR-RC type filtration the variancy of the noise output is determined. The new term ''second noise-corner time constant'' was proposed. The expression for relative signal-to-noise ratio as the dependence on the noise as well as circuits time constants was derived. It was also presented in a graphical form. 12 refs., 6 figs. (author)

  16. Methanogenesis in Thermophilic Biogas Reactors

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær

    1995-01-01

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

  17. Carbohydrates in thermophile metabolism: calculation of the standard molal thermodynamic properties of aqueous pentoses and hexoses at elevated temperatures and pressures

    Science.gov (United States)

    Amend, Jan P.; Plyasunov, Andrey V.

    2001-11-01

    Experimental thermodynamic data for aqueous organic compounds can be combined with the revised Helgeson-Kirkham-Flowers (HKF) equations of state to generate parameters that can be used to estimate standard molal properties as functions of temperature and pressure. In this study, we regressed thermodynamic data for aqueous carbohydrates at temperatures up to 393 K reported in the literature to permit the calculation of the apparent standard molal Gibbs free energies and enthalpies of formation (ΔGo and ΔHo, respectively) and the standard molal entropies (S2o), heat capacities (CP,2o), and volumes (V2o) to 423 K and several hundred MPa of aqueous C5 aldoses (ribose, arabinose, xylose, lyxose) and C5 ketoses (ribulose, xylulose) as well as C6 aldoses (glucose, mannose, galactose) and C6 ketoses (fructose, sorbose). Values of ΔGo for these 11 aqueous carbohydrates are given as a function of temperature at the saturated water vapor pressure (PSAT) and at 50 MPa. Values of ΔGo for aqueous glucose are then combined with those of other aqueous organic and inorganic compounds to calculate values of the standard molal Gibbs free energies of 13 fermentation and respiration reactions (ΔGro) known or likely to be carried out by thermophilic microorganisms. Finally, values of the overall Gibbs free energies of these reactions (ΔGr) are calculated at the temperature, pressure, and chemical composition that obtain in the hydrothermal fluids of Vulcano Island, southern Italy, a site that is widely known for its tremendous diversity of organisms able to live at high temperatures. At likely activities of aqueous glucose, it is shown that thermophiles in the hot springs of Vulcano at 373 K and ∼0.1 MPa can gain between 400 and 3000 kJ per mole of glucose fermented or respired.

  18. Temperature Field-Wind Velocity Field Optimum Control of Greenhouse Environment Based on CFD Model

    Directory of Open Access Journals (Sweden)

    Yongbo Li

    2014-01-01

    Full Text Available The computational fluid dynamics technology is applied as the environmental control model, which can include the greenhouse space. Basic environmental factors are set to be the control objects, the field information is achieved via the division of layers by height, and numerical characteristics of each layer are used to describe the field information. Under the natural ventilation condition, real-time requirements, energy consumption, and distribution difference are selected as index functions. The optimization algorithm of adaptive simulated annealing is used to obtain optimal control outputs. A comparison with full-open ventilation shows that the whole index can be reduced at 44.21% and found that a certain mutual exclusiveness exists between the temperature and velocity field in the optimal course. All the results indicate that the application of CFD model has great advantages to improve the control accuracy of greenhouse.

  19. Study on the optimum design of a high temperature superconducting coil

    International Nuclear Information System (INIS)

    Ishiguri, Shinichi; Yamaguchi, Mitsugi; Fukui, Satoshi; Ogawa, Jun; Sato, Takao

    2005-01-01

    It is in particular of importance for HTS coils to secure a larger central magnetic field, a large stored energy, etc. with shorter length of HTS tapes. The critical current of an HTS tape depends on both the flux density and the flux angle with respect to tapes. In view of this, the performance improvement of HTS coils is taken into account with an analytical model. As a coil shape, the minimum volume coil derived from the Fabry Factor constant curve is taken up, which is often employed at low temperature coils. The electric field distribution within a coil cross-section is calculated to examine effects on a current carrying capability. It is clear that high electric field portions appear at the coil edge region due primarily to inclined magnetic fluxes against HTS tapes. Considering this, a grade winding method of a coil is proposed, where the winding density of conductors is reduced at coil edge portions. With this coil winding structure, the critical current of an HTS coil is improved since the magnetic field is reduced at edge portions. The stored energy per HTS tape length and the central magnetic field of the coil can be remarkably increased by this kind of grade winding method

  20. ESTIMATION OF EXTRACELLULAR LIPOLYTIC ENZYME ACTIVITY BY THERMOPHILIC BACILLUS SP. ISOLATED FROM ARID AND SEMI-ARID REGION OF RAJASTHAN, INDIA

    Directory of Open Access Journals (Sweden)

    Deeksha Gaur

    2012-10-01

    Full Text Available Thermophilic organisms can be defined as, micro-organisms which are adapted to survive at high temperatures. The enzymes secreted by thermophilic bacteria are capable of catalyzing biochemical reactions at high temperatures. Thermophilic bacteria are able to produce thermostable lipolytic enzymes (capable of degradation of lipid at temperatures higher than mesophilic bacteria. Therefore, the isolation of thermophilic bacteria from natural sources and their identification are quite beneficial in terms of discovering thermostable lipase enzymes. Due to great temperature fluctuation in hot arid and semi-arid region of Rajasthan, this area could serve as a good source for new thermophilic lipase producing bacteria with novel industrially important properties. The main objective of this research is the isolation and estimation of industrially important thermophilic lipase enzyme produced by thermophilic bacteria, isolated from arid and semi-arid region of Rajasthan. For this research purpose soil samples were collected from Churu, Sikar and Jhunjunu regions of Rajasthan. Total 16 bacterial strains were isolated and among only 2 thermostable lipolytic enzyme producing bacteria were charcterized. The thermostable lipolytic enzyme was estimated by qualitative and quantitative experiments. The isolates were identified as Bacillus sp. by microscopic, biochemical and molecular characterization. The optimum enzyme activity was observed at pH 8, temperature 60°C and 6% salt concentrations at 24 hrs time duration. Lipolytic enzyme find useful in a variety of biotechnological fields such as food and dairy (cheese ripening, flavour development, detergent, pharmaceutical (naproxen, ibuprofen, agrochemical (insecticide, pesticide and oleochemical (fat and oil hydrolysis, biosurfactant synthesis industries. Lipolytic enzyme can be further used in many newer areas where they can serve as potential biocatalysts.

  1. Growth media in anaerobic fermentative processes: The underestimated potential of thermophilic fermentation and anaerobic digestion.

    Science.gov (United States)

    Hendriks, A T W M; van Lier, J B; de Kreuk, M K

    Fermentation and anaerobic digestion of organic waste and wastewater is broadly studied and applied. Despite widely available results and data for these processes, comparison of the generated results in literature is difficult. Not only due to the used variety of process conditions, but also because of the many different growth media that are used. Composition of growth media can influence biogas production (rates) and lead to process instability during anaerobic digestion. To be able to compare results of the different studies reported, and to ensure nutrient limitation is not influencing observations ascribed to process dynamics and/or reaction kinetics, a standard protocol for creating a defined growth medium for anaerobic digestion and mixed culture fermentation is proposed. This paper explains the role(s) of the different macro- and micronutrients, as well as the choices for a growth medium formulation strategy. In addition, the differences in nutrient requirements between mesophilic and thermophilic systems are discussed as well as the importance of specific trace metals regarding specific conversion routes and the possible supplementary requirement of vitamins. The paper will also give some insight into the bio-availability and toxicity of trace metals. A remarkable finding is that mesophilic and thermophilic enzymes are quite comparable at their optimum temperatures. This has consequences for the trace metal requirements of thermophiles under certain conditions. Under non-limiting conditions, the trace metal requirement of thermophilic systems is about 3 times higher than for mesophilic systems. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Evaluation of base, optimum and ceiling temperature for (Kochia scoparia L. Schard with application of Five-Parameters-Beta Model

    Directory of Open Access Journals (Sweden)

    S. Sabouri Rad

    2016-05-01

    Full Text Available Kochia (Kochia scoparia L. Schard is an annual, halophyte and drought resistant plant, that it can be irrigated with saline water and a valuable source for forage under drought and saline ecosystems. In order to evaluate germination characteristics of kochia, an experiment was conducted at Physiology laboratory of Ferdowsi University of Mashhad, Iran, during 2009. This experiment was conducted in a completely randomized design with four replications. Germination was evaluated at 5, 10, 15, 20, 25, 30, 35 and 40°C under dark germinator with 50-60 percentage relative humidity. The results showed that the highest germination percentage was obtained at 20-30°C and the lowest obtained at 40°C. The longest and the shortest period to 20 and 50 germination percentage were recorded to 5-10°C and 20-30°C, respectively. The longest and the shortest period to 80 percentage germination were belonging to 15 and 30°C, respectively. Based on Five Parameters Beta model, base, optimum and ceiling temperatures for kochia estimated 3.4, 25 and 43.3°C, respectively. However, seed of this plant is able to germinate in wide temperature range.

  3. Influence of temperature on the fixation and penetration of silver during the chalcopyrite leaching using moderate thermophilic microorganisms

    International Nuclear Information System (INIS)

    Cancho, L.; Blazquez, M. L.; Munoz, J. A.; Gonzalez, F.; Ballester, A.

    2004-01-01

    Bio leaching of chalcopyrite using mesophilic microorganisms considerable improves in the presence of silver. However, the studies carried out with moderate thermophilic microorganisms do not show a significant improvement with regard to the use of mesophilic bacteria. The main objective of the present work has been to study the silver fixation on chalcopyrite ar 35 and 45 degree centigree and its influence on the microbiological attack. Different observations using SEM, EDS microanalysis and concentration profiles using electron microprobe have been carried out. The study of the different samples showed that silver fixation was more favourable at 35 degree centigree than at 45 degree centigree. In addition, bacterial action improved silver penetration through attack cracks. (Author)

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

    Science.gov (United States)

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

    2011-12-01

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

  5. Performance characteristics and parametric optimum criteria of a Brownian micro-refrigerator in a spatially periodic temperature field

    International Nuclear Information System (INIS)

    Lin Bihong; Chen Jincan

    2009-01-01

    It is shown that a microscopic system consisting of Brownian particles moving in a spatially asymmetric but periodic potential (ratchet) and contacting with the alternating hot and cold reservoirs along space coordinate and an external force applying on the particles may work as a refrigerator. In order to clarify the underlying physical pictures of the system, the heat flows via both the potential energy and the kinetic energy of the particles are considered simultaneously. Based on an Arrhenius' factor describing the forward and backward particle currents, expressions for some important performance parameters of the refrigerator, such as the coefficient of performance, cooling rate and power input, are derived analytically. The maximum coefficient of performance and cooling rate are numerically calculated for some given parameters. The influence of the main parameters such as the external force, barrier height of the potential, asymmetry of the potential and temperature ratio of the heat reservoirs on the performance of the Brownian refrigerator is discussed. The optimum criteria of some characteristic parameters are given. It is found that the Brownian refrigerator may be controlled to operate in different regions through the choice of several parameters

  6. The effect of noble metal additives on the optimum operating temperature of SnO2 gas sensors

    Science.gov (United States)

    Mohammad-Yousefi, S.; Rahbarpour, S.; Ghafoorifard, H.

    2017-12-01

    The effect of Pd and Au additives on gas sensing properties of SnO2 was investigated. SnO2 pallets were fabricated and sintered at 900 °C for 90 minutes. Several nanometer layers of Pd and Au were deposited on separate SnO2 pallets and were intentionally dispersed into the SnO2 pallets by long heat treatment (400 °C for 1 Day). All metal loaded samples showed significant enhancement in response level and optimum operating temperature compare to pure SnO2 gas sensors. The amount of enhancement was strongly dependent on the material and the thickness of deposited metal layer. Studying butanol response showed that increasing the thickness of metal causes the response level to increase. Further thickness increase caused contrary effect and decreased the performance of sensors. Best results were achieved at 10 nm-thick Au and 7 nm-thick Pd. Generally, Pd-SnO2 samples demonstrated better performance than Au-SnO2 ones, however, Au-SnO2 samples were proved to be good candidate to sense reducing gases with lower hydrogen atoms in their formula. Given experimental results were also good evidence of chemical activity of gold and simply confirms the relation between chemical activity and gold particle size. Results were qualitatively described by gas diffusion theory and surface reactions take place on metal particles.The first section in your paper

  7. Optimization of extracellular thermophilic highly alkaline lipase from thermophilic bacillus sp isolated from hotspring of Arunachal Pradesh, India

    Science.gov (United States)

    Bora, Limpon; Bora, Minakshi

    2012-01-01

    Studies on lipase production were carried out with a bacterial strain (Bacillus sp LBN 2) isolated from soil sample of hotspring of Arunachal Pradesh, India. The cells were cultivated in a mineral medium with maximum production at 1% groundnut oil. The optimum temperature and initial medium pH for lipase production by the organism were 500C and 9.0 respectively. The molecular mass was found to be 33KDa by SDS PAGE. The optimal pH and temperature for activity were 10 and 600C respectively. The enzyme was found to be stable in the pH range of 8–11 with 90% retention of activity at pH 11. The enzyme retained 90% activity at 600C and 70% of activity at 700C for 1h. The lipase was found to be stable in acetone followed by ethanol. The present findings suggested the enzyme to be thermophilic alkaline lipase. PMID:24031801

  8. Thermophilic and alkalophilic xylanases from several Dictyoglomus isolates

    Energy Technology Data Exchange (ETDEWEB)

    Mathrani, I M; Ahring, B K [Technical Univ. of Denmark, Lyngby (Denmark). Anaerobic Microbiology/Biotechnology Group

    1992-10-01

    Supernatant xylanases from three thermophilic and strictly anaerobic Dictyoglomus strains isolated from very different environments were examined: The type species, D. thermophilum[sup T], from a hot-spring in Japan; strain B1, a recently described strictly xylanutilizing Dictyoglomus from a paper-pulp factory in Finland; and strain B4a, isolated from a thermal pool on Iceland. The highest enzymatic activity observed from batch-culture supernatant with 4 g l[sup -1] of beech xylan as growth substrate was 3.8x10[sup -6] kat l[sup -1]. The K[sub m] for the xylanases of strain B1 was 4.7 g beech xylan l[sup -1]. The xylanases of all the isolates had a broad range of activity with respect to pH, showing good activity from pH 5.5 to near 9.0. The xylanases from the three isolates had a very high temperature optimum of 80deg C, maximum temperature for extended activity between 80 and 90deg C, and a thermal half-life of over 1 h at 90deg C for strain B1. The application of thermophilic alkalophilic xylanases to paper pulping was discussed. (orig.).

  9. OPTIMUM PROSESSENTRERING

    Directory of Open Access Journals (Sweden)

    K. Adendorff

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: The paper derives an expression for optimum process centreing for a given design specification and spoilage and/or rework costs.

    AFRIKAANSE OPSOMMING: Die problem Van prosessentrering vir n gegewe ontwerpspesifikasie en herwerk- en/of skrootkoste word behandel.

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

    DEFF Research Database (Denmark)

    Elsgaard, Lars; Prieur, Daniel

    2010-01-01

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

  11. Isolation and characterization of a heavy metal-resistant, thermophilic esterase from a Red Sea Brine Pool

    KAUST Repository

    Mohamed, Yasmine M.; Ghazy, Mohamed A.; Sayed, Ahmed; Ouf, Amged; El-Dorry, Hamza; Siam, Rania

    2013-01-01

    The Red Sea Atlantis II brine pool is an extreme environment that displays multiple harsh conditions such as high temperature, high salinity and high concentrations of multiple, toxic heavy metals. The survival of microbes in such an environment by utilizing resistant enzymes makes them an excellent source of extremophilic enzymes. We constructed a fosmid metagenomic library using DNA isolated from the deepest and most secluded layer of this pool. We report the isolation and biochemical characterization of an unusual esterase: EstATII. EstATII is thermophilic (optimum temperature, 65 C), halotolerant (maintains its activity in up to 4.5â€...M NaCl) and maintains at least 60% of its activity in the presence of a wide spectrum of heavy metals. The combination of biochemical characteristics of the Red Sea Atlantis II brine pool esterase, i.e., halotolerance, thermophilicity and resistance to heavy metals, makes it a potentially useful biocatalyst.

  12. Isolation and characterization of a heavy metal-resistant, thermophilic esterase from a Red Sea Brine Pool

    KAUST Repository

    Mohamed, Yasmine M.

    2013-11-28

    The Red Sea Atlantis II brine pool is an extreme environment that displays multiple harsh conditions such as high temperature, high salinity and high concentrations of multiple, toxic heavy metals. The survival of microbes in such an environment by utilizing resistant enzymes makes them an excellent source of extremophilic enzymes. We constructed a fosmid metagenomic library using DNA isolated from the deepest and most secluded layer of this pool. We report the isolation and biochemical characterization of an unusual esterase: EstATII. EstATII is thermophilic (optimum temperature, 65 C), halotolerant (maintains its activity in up to 4.5â€...M NaCl) and maintains at least 60% of its activity in the presence of a wide spectrum of heavy metals. The combination of biochemical characteristics of the Red Sea Atlantis II brine pool esterase, i.e., halotolerance, thermophilicity and resistance to heavy metals, makes it a potentially useful biocatalyst.

  13. Effect of temperature and pH on the actiity of ribulose 1,5-diphosphate carboxylase from the thermophilic hydrogen bacterium Pseudomonas thermophila

    Energy Technology Data Exchange (ETDEWEB)

    Romanova, A K; Emnova, E E; Zykalova, K A

    1980-01-01

    The activity of ribulose 1,5-diphosphate (RDP) carboxylase was found in the soluble fraction of the cytoplasm from sonicated Pseudomonas thermophila K-2 cells. The enzyme is relatively thermolabile and completey loses its activity at 80/sup 0/C. The activity of RDP carboxylase at 60/sup 0/C increases by 40% during the first 10 min of heating in the presence of Mg/sup 2 +/ ions, bicarbonate and dithiothreitol, and again decreases if the enzyme is heated over 20 min. The optimum temperature of the enzyme is 50 to 55/sup 0/C. The specific activity of the enzyme in fresh preparations under these conditions reaches 0.22 unit per 1 mg of protein in the extract. The calculated value of the activation energy for RDP carboxylase is 6.4 keal.mole/sup -1/, but 11.6 kcal.mole/sup -1/ in frozen preparations. The optimal pH is 7.0 to 7.3 depending on the buffer. The temperature optimum for the enzyme action does not depend on pH within the range of 7.3 to 8.8. Therefore, RDP carboxylase of Ps, thermophila K-2 differs from RDP carboxylases of mesophilic cultures studied earlier by a higher susceptibility to a decrease in temeprature (the enzyme activity is negligible at 30/sup 0/C), by a lower value of the activation energy at suboptimal temperatures, and by a lower pH optimum of the enzyme action.

  14. Energy transduction and transport processes in thermophilic bacteria

    NARCIS (Netherlands)

    Konings, W. N.; Tolner, B.; Speelmans, G.; Elferink, M. G. L.; de Wit, J. G.; Driessen, A. J. M.

    1992-01-01

    Bacterial growth at the extremes of temperature has remained a fascinating aspect in the study of membrane function and structure. The stability of the integral membrane proteins of thermophiles make them particularly amenable to study. Respiratory enzymes of thermophiles appear to be functionally

  15. Thermal effects on metabolic activities of thermophilic microorganisms from the thermal discharge point of Tuticorin thermal power plant area

    International Nuclear Information System (INIS)

    Muthukkannan, N.; Murugesan, A.G.

    2002-01-01

    Metabolic activities of thermophilic microorganisms isolated from the thermal water discharge point at Tuticorin thermal power station were studied by growing the microorganisms in sterile medium and at various temperature regimes of 25, 35, 45, 55 and 65degC. The optimum temperature for the growth of the bacterium isolated from the thermal power plant station was 45 degC and beyond 65 degC the growth was gradually decreased. The bacteria isolated from open sea water were mesophiles with their growth optimum at 35 degC and microbes inhabiting the thermal discharge area were thermopiles as they were tolerant even at 55 degC. The amylase production, carbohydrate metabolism and lactose fermentation activities were optimum at 45 degC. At 25 degC and beyond 65 degC biochemical activities of the organisms were inhibited to a greater extent. (author)

  16. 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.

  17. Simultaneous Production of Hydrogen and Methane from Sugar Beet Molasses in a Two Phase Anaerobic Digestion System in UASB Reactors under Thermophilic Temperature (55 Deg C)

    Energy Technology Data Exchange (ETDEWEB)

    Kongjan, P.; Villafa, S.; Beltran, P.; Min, B.; Angelidaki, I. (Dept. of Environmental Engineering, Technical Univ. of Denmark, DK-2800, Lyngby (Denmark)). e-mail: pak@env.dtu.dk

    2008-10-15

    Simultaneous production of hydrogen and methane in two sequential stages of acidogenic and methanogenic step was investigated in two serial operated up-flow anaerobic sludge bed (UASB) reactors at thermophilic temperature (55 deg C). Hydrogen production from molasses was carried out in the first reactor at the hydraulic retention time (HRT) of 1 day. Molasses were converted into hydrogen with the yield of 1.3 mole-H{sub 2}/mole-hexose{sub added} or 82.7 ml- H{sub 2}/g-VS{sub added} of molasses, and the hydrogen productivity was 2696 ml-H{sub 2}/dxl{sub reactor}. The effluent (mainly butyrate, acetate and lactate) after the acidogenic process was subsequently fed to the second reactor for methane production at HRT of 3 days. Methane production yield of 255 ml-H{sub 2}/g-VS{sub added} of influent or 130.1 ml-H{sub 2}/g-VS{sub added} of molasses and methane production rate of 1056 ml/dxl{sub reactor} were obtained. Significant decrease of volatile fatty acids (VFAs) was also observed in the effluent of the second reactor. A two phase anaerobic digestion was successfully demonstrated for molasses as a potential substrate to produce hydrogen and subsequent methane in the UASB reactors

  18. (Hyper)thermophilic Enzymes: Production and Purification

    NARCIS (Netherlands)

    Falcicchio, P.; Levisson, M.; Kengen, S.W.M.; Koutsopoulos, S.

    2014-01-01

    The discovery of thermophilic and hyperthermophilic microorganisms, thriving at environmental temperatures near or above 100 °C, has revolutionized our ideas about the upper temperature limit at which life can exist. The characterization of (hyper)thermostable proteins has broadened our

  19. Determination of the optimum temperature history of inlet water for minimizing thermal stresses in a pipe by the multiphysics inverse analysis

    International Nuclear Information System (INIS)

    Kubo, S; Uchida, K; Ishizaka, T; Ioka, S

    2008-01-01

    It is important to reduce the thermal stresses for managing and extending the lives of pipes in plants. In this problem, heat conduction, elastic deformation, heat transfer, liquid flow should be considered, and therefore the problem is of a multidisciplinary nature. An inverse method was proposed by the present authors for determining the optimum thermal load history which reduced transient thermal stress considering the multidisciplinary physics. But the obtained solution had a problem that the temperature increasing rate of inner surface of the pipe was discontinuous at the end time of heat up. In this study we introduce temperature history functions that ensure the continuity of the temperature increasing rate. The multidisciplinary complex problem is decomposed into a heat conduction problem, a heat transfer problem, and a thermal stress problem. An analytical solution of the temperature distribution of radial thickness and thermal hoop stress distribution is obtained. The maximum tensile and compressive hoop stresses are minimized for the case where inner surface temperature T s (t) is expressed in terms of the 4th order polynomial function of time t. Finally, from the temperature distributions, the optimum fluid temperature history is obtained for reducing the thermal stresses.

  20. PRODUCTION AND CHARACTERIZATION OF THERMOPHILIC CARBOXYMETHYL CELLULASE SYNTHESIZED BY Bacillus sp. GROWING ON SUGARCANE BAGASSE IN SUBMERGED FERMENTATION

    Directory of Open Access Journals (Sweden)

    I. Q. M. Padilha

    2015-03-01

    Full Text Available Abstract The production and characterization of cellulase from thermophilic strain Bacillus sp. C1AC5507 was studied. For enzyme production, sugarcane bagasse was used as carbon source. The produced carboxymethyl cellulase (CMCase had a molecular weight around 55 kDa and its activity varied between 0.14 and 0.37 IU mL-1 in conditions predicted by Response Surface Methodology. The optimum temperature and pH for the CMCase production were 70 °C and 7.0, respectively. The enzyme activity was inhibited mostly by Cu+2 and activated mostly by Co+2, Mn2+, Ca+2 and Fe+3. Our findings provide a contribution to the use of natural wastes such as sugarcane bagasse as substrate for growth and production of thermophilic CMCase. Further optimization to increase the production of cellulase enables the use in industrial applications.

  1. Thermophilic and unusually acidophilic amylase produced by a thermophilic acidophilic bacillus sp

    Energy Technology Data Exchange (ETDEWEB)

    Uchino, F

    1982-01-01

    Bacillus sp. 11-1S, a thermophilic acidophilic bacterial strain, produced an extracellular amylase with unusual characteristics. The enzyme was purified 40-fold by SE-Sephadex column chromatography. The pH optimum for activity was 2.0, and substantial activity was noted in the pH range of 1.5-3.5. The optimal temperature was 70 degrees C, but the activity decreased markedly in lower reaction temperatures. Arrhenius plots of the reaction showed two straight lines intersecting at about 50 degrees C. The activity or stability of the enzyme was not likely to depend on Ca2+. The molecular weight of the enzyme was 54,000 calculated from the electrophoretic mobility. The enzyme behaved like an alpha-amylase (1,4-alpha-D- glucan glucanohydrolase, E.C. 3.2.1.1). About 34% of glucosidic linkages of soluble starch was hydrolyzed at 65 degrees C and pH 2.0, in 24 hours, and the major products were maltotriose and maltose. (Refs. 14).

  2. Thermostable 𝜶-Amylase Activity from Thermophilic Bacteria Isolated from Bora Hot Spring, Central Sulawesi

    Science.gov (United States)

    Gazali, F. M.; Suwastika, I. N.

    2018-03-01

    α-Amylase is one of the most important enzyme in biotechnology field, especially in industrial application. Thermostability of α-Amylase produced by thermophilic bacteria improves industrial process of starch degradation in starch industry. The present study were concerned to the characterization of α-Amylase activity from indigenous thermophilic bacteria isolated from Bora hot spring, Central Sulawesi. There were 18 isolates which had successfully isolated from 90°C sediment samples of Bora hot spring and 13 of them showed amylolytic activity. The α-Amylase activity was measured qualitatively at starch agar and quantitatively based on DNS (3,5-Dinitrosalicylic acid) methods, using maltose as standard solution. Two isolates (out of 13 amylolytic bacteria), BR 002 and BR 015 showed amylolytic index of 0.8 mm and 0.5 mm respectively, after being incubated at 55°C in the 0.002% Starch Agar Medium. The α-Amylase activity was further characterized quantitatively which includes the optimum condition of pH and temperature of α-Amylase crude enzyme from each isolate. To our knowledge, this is the first report on isolation and characterization of a thermostable α-Amylase from thermophilic bacteria isolated from Central Sulawesi particularly from Bora hot spring.

  3. Measurement of temperature elevation in tissue for the optimum and safe use of scalpel-type ultrasonic surgery devices

    International Nuclear Information System (INIS)

    Koch, C; Nuernberger, H; Reimann, H P

    2004-01-01

    Using temperature sensors of specific design, the temperature elevation during application of a Harmonic Scalpel was determined in liver tissue. The influence of different treatment techniques and application parameters on the heat produced was determined. The measurements can be used to assess the risk of harmful bioeffects and to optimise performance and treatment techniques with respect to minimum thermal load

  4. Caldanaerobacter uzonensis sp. nov., an anaerobic, thermophilic, heterotrophic bacterium isolated from a hot spring.

    Science.gov (United States)

    Kozina, Irina V; Kublanov, Ilya V; Kolganova, Tatyana V; Chernyh, Nikolai A; Bonch-Osmolovskaya, Elizaveta A

    2010-06-01

    An anaerobic thermophilic bacterium, strain K67(T), was isolated from a terrestrial hot spring of Uzon Caldera, Kamchatka Peninsula. Analysis of the 16S rRNA gene sequence revealed that the novel isolate belongs to the genus Caldanaerobacter, with 95 % 16S rRNA gene sequence similarity to Caldanaerobacter subterraneus subsp. subterraneus SEBR 7858(T), suggesting that it represents a novel species of the genus Caldanaerobacter. Strain K67(T) was characterized as an obligate anaerobe, a thermophile (growth at 50-75 degrees capital ES, Cyrillic; optimum 68-70 degrees C), a neutrophile (growth at pH(25 degrees C) 4.8-8.0; optimum pH(25 degrees C) 6.8) and an obligate organotroph (growth by fermentation of various sugars, peptides and polysaccharides). Major fermentation products were acetate, H2 and CO2; ethanol, lactate and l-alanine were formed in smaller amounts. Thiosulfate stimulated growth and was reduced to hydrogen sulfide. Nitrate, sulfate, sulfite and elemental sulfur were not reduced and did not stimulate growth. Thus, according to the strain's phylogenetic position and phenotypic novelties (lower upper limit of temperature range for growth, the ability to grow on arabinose, the inability to reduce elemental sulfur and the formation of alanine as a minor fermentation product), the novel species Caldanaerobacter uzonensis sp. nov. is proposed, with the type strain K67(T) (=DSM 18923(T) =VKM capital VE, Cyrillic-2408(T)).

  5. Thermophilic lignocellulose deconstruction.

    Science.gov (United States)

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

    2014-05-01

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

  6. Estimation of extracellular lipase enzyme produced by thermophilic bacillus sp. isolated from arid and semi-arid region of Rajasthan, India

    OpenAIRE

    Deeksha Gaur; Pankaj Kumar Jain; Yamini Singh Sisodia; Vivek Bajpai

    2012-01-01

    Thermophilic organisms can be defined as microorganisms which are adapted to live at high temperatures. The enzymes produce by thermophilic bacteria are capable of catalyzing biochemical reactions at high temperatures. Thermophilic bacteria are able to produce thermostable lipase enzymes capable of degradation of lipid at temperatures higher than those of mesophilic bacteria. Therefore, the isolation of thermophilic bacteria from natural sources and their identification are quite useful in te...

  7. Effect of Temperature on Wettability and Optimum Wetting Conditions for Maximum Oil Recovery in Carbonate Reservoir System

    DEFF Research Database (Denmark)

    Sohal, Muhammad Adeel Nassar; Thyne, Geoffrey; Søgaard, Erik Gydesen

    2017-01-01

    The additional oil recovery from fractured & oil-wet carbonates by ionically modified water is principally based on changing wettability and often attributed to an improvement in water wetness. The influence of different parameters like dilution of salinity, potential anions, temperature, pressure......, lithology, pH, oil acid and base numbers to improve water wetting has been tested in recovery experiments. In these studies temperature is mainly investigated to observe the reactivity of potential anions (SO42-, PO33-, and BO33-) at different concentrations. But the influence of systematically increasing...... and 100 times. It was observed that as temperature increased the water-wetness decreased for seawater and seawater dilutions, however, the presence of elevated sulfate can somewhat counter this trend as sulfate increased oil wetting....

  8. Predicted optimum ambient temperatures for broiler chickens to dissipate metabolic heat do not affect performance or improve breast muscle quality.

    Science.gov (United States)

    Zahoor, I; Mitchell, M A; Hall, S; Beard, P M; Gous, R M; De Koning, D J; Hocking, P M

    2016-01-01

    An experiment was conducted to test the hypothesis that muscle damage in fast-growing broiler chickens is associated with an ambient temperature that does not permit the birds to lose metabolic heat resulting in physiological heat stress and a reduction in meat quality. The experiment was performed in 4 climate chambers and was repeated in 2 trials using a total of 200 male broiler chickens. Two treatments compared the recommended temperature profile and a cool regimen. The cool regimen was defined by a theoretical model that determined the environmental temperature that would enable heat generated by the bird to be lost to the environment. There were no differences in growth rate or feed intake between the two treatments. Breast muscles from birds on the recommended temperature regimen were lighter, less red and more yellow than those from the cool temperature regimen. There were no differences in moisture loss or shear strength but stiffness was greater in breast muscle from birds housed in the cool compared to the recommended regimen. Histopathological changes in the breast muscle were similar in both treatments and were characterised by mild to severe myofibre degeneration and necrosis with regeneration, fibrosis and adipocyte infiltration. There was no difference in plasma creatine kinase activity, a measure of muscle cell damage, between the two treatments consistent with the absence of differences in muscle pathology. It was concluded that breast muscle damage in fast-growing broiler chickens was not the result of an inability to lose metabolic heat at recommended ambient temperatures. The results suggest that muscle cell damage and breast meat quality concerns in modern broiler chickens are related to genetic selection for muscle yields and that genetic selection to address breast muscle integrity in a balanced breeding programme is imperative.

  9. 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...

  10. New thermophilic anaerobes that decompose crystalline cellulose

    Energy Technology Data Exchange (ETDEWEB)

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

    1985-01-01

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

  11. 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

  12. Determination of the Optimum Heat Transfer Coefficient and Temperature Rise Analysis for a Lithium-Ion Battery under the Conditions of Harbin City Bus Driving Cycles

    Directory of Open Access Journals (Sweden)

    Xiaogang Wu

    2017-10-01

    Full Text Available This study investigated the heat problems that occur during the operation of power batteries, especially thermal runaway, which usually take place in high temperature environments. The study was conducted on a ternary polymer lithium-ion battery. In addition, a lumped parameter thermal model was established to analyze the thermal behavior of the electric bus battery system under the operation conditions of the driving cycles of the Harbin city electric buses. Moreover, the quantitative relationship between the optimum heat transfer coefficient of the battery and the ambient temperature was investigated. The relationship between the temperature rise (Tr, the number of cycles (c, and the heat transfer coefficient (h under three Harbin bus cycles have been investigated at 30 °C, because it can provide a basis for the design of the battery thermal management system. The results indicated that the heat transfer coefficient that meets the requirements of the battery thermal management system is the cubic power function of the ambient temperature. Therefore, if the ambient temperature is 30 °C, the heat transfer coefficient should be at least 12 W/m2K in the regular bus lines, 22 W/m2K in the bus rapid transit lines, and 32 W/m2K in the suburban lines.

  13. Production and characterization of an acido-thermophilic, organic solvent stable cellulase from Bacillus sonorensis HSC7 by conversion of lignocellulosic wastes

    Directory of Open Access Journals (Sweden)

    Fatemeh Azadian

    2017-06-01

    Full Text Available The acidophilic and thermophilic cellulase would facilitate the conversion of lignocellulosic biomass to biofuel. In this study, Bacillus sonorensis HSC7 isolated as the best thermophilic cellulose degrading bacterium from Gorooh hot spring. 16S rRNA gene sequencing showed that, this strain closely related to the B. sonorensis. CMCase production was considered under varying environmental parameters. Results showed that, sucrose and (NH42SO4 were obtained as the best carbon and nitrogen sources for CMCase production. B. sonorensis HSC7 produced CMCase during the growth in optimized medium supplemented with agricultural wastes as sole carbon sources. The enzyme was active with optimum temperature of 70 °C and the optimum CMCase activity and stability observed at pH 4.0 and 5.0, respectively. These are characteristics indicating that, this enzyme could be an acidophilic and thermophilic CMCase. Furthermore, the CMCase activity improved by methanol (166%, chloroform (152%, while it was inhibited by DMF (61%. The CMCase activity was enhanced in the presence of Mg+2 (110%, Cu+2 (116%, Triton X-100 (118% and it retained 57% of its activity at 30% NaCl. The compatibility of HSC7 CMCase varied for each laundry detergent, with higher stability being observed in the presence of Taj® and darya®. This enzyme, that is able to work under extreme conditions, has potential applications in various industries.

  14. Thermophilic biofiltration of benzene and toluene.

    Science.gov (United States)

    Cho, Kyung-Suk; Yoo, Sun-Kyung; Ryu, Hee Wook

    2007-12-01

    In the current studies, we characterized the degradation of a hot mixture of benzene and toluene (BT) gases by a thermophilic biofilter using polyurethane as packing material and high-temperature compost as a microbial source. We also examined the effect of supplementing the biofilter with yeast extract (YE). We found that YE substantially enhanced microbial activity in the thermophilic biofilter. The degrading activity of the biofilter supplied with YE was stable during long-term operation (approximately 100 d) without accumulating excess biomass. The maximum elimination capacity (1,650 g x m(-3) h(-1)) in the biofilter supplemented with YE was 3.5 times higher than that in the biofilter without YE (470 g g x m(-3) h(-1)). At similar retention times, the capacity to eliminate BT for the YE-supplemented biofilter was higher than for previously reported mesophilic biofilters. Thus, thermophilic biofiltration can be used to degrade hydrophobic compounds such as a BT mixture. Finally, 16S rDNA polymerase chain reaction-DGGE (PCR-DGGE) fingerprinting revealed that the thermophilic bacteria in the biofilter included Rubrobacter sp. and Mycobacterium sp.

  15. A dye-decolorizing peroxidase from Bacillus subtilis exhibiting substrate-dependent optimum temperature for dyes and β-ether lignin dimer

    Science.gov (United States)

    Min, Kyoungseon; Gong, Gyeongtaek; Woo, Han Min; Kim, Yunje; Um, Youngsoon

    2015-01-01

    In the biorefinery using lignocellulosic biomass as feedstock, pretreatment to breakdown or loosen lignin is important step and various approaches have been conducted. For biological pretreatment, we screened Bacillus subtilis KCTC2023 as a potential lignin-degrading bacterium based on veratryl alcohol (VA) oxidation test and the putative heme-containing dye-decolorizing peroxidase was found in the genome of B. subtilis KCTC2023. The peroxidase from B. subtilis KCTC2023 (BsDyP) was capable of oxidizing various substrates and atypically exhibits substrate-dependent optimum temperature: 30°C for dyes (Reactive Blue19 and Reactive Black5) and 50°C for high redox potential substrates (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid [ABTS], VA, and veratryl glycerol-β-guaiacyl ether [VGE]) over +1.0 V vs. normal hydrogen electrode. At 50°C, optimum temperature for high redox potential substrates, BsDyP not only showed the highest VA oxidation activity (0.13 Umg−1) among the previously reported bacterial peroxidases but also successfully achieved VGE decomposition by cleaving Cα-Cβ bond in the absence of any oxidative mediator with a specific activity of 0.086 Umg−1 and a conversion rate of 53.5%. Based on our results, BsDyP was identified as the first bacterial peroxidase capable of oxidizing high redox potential lignin-related model compounds, especially VGE, revealing a previously unknown versatility of lignin degrading biocatalyst in nature. PMID:25650125

  16. Thermophilic Sulfate-Reducing Bacteria in Cold Marine Sediment

    DEFF Research Database (Denmark)

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

    1994-01-01

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

  17. Cellulolytic potential of thermophilic species from four fungal orders

    DEFF Research Database (Denmark)

    Busk, Peter Kamp; Lange, Lene

    2013-01-01

    and in characterization of their industrially useful enzymes. In the present study we investigated the cellulolytic potential of 16 thermophilic fungi from the three ascomycete orders Sordariales, Eurotiales and Onygenales and from the zygomycete order Mucorales thus covering all fungal orders that include thermophiles....... Thermophilic fungi are the only described eukaryotes that can grow at temperatures above 45 ºC. All 16 fungi were able to grow on crystalline cellulose but their secreted enzymes showed widely different cellulolytic activities, pH optima and thermostabilities. Interestingly, in contrast to previous reports, we......Elucidation of fungal biomass degradation is important for understanding the turnover of biological materials in nature and has important implications for industrial biomass conversion. In recent years there has been an increasing interest in elucidating the biological role of thermophilic fungi...

  18. Thermophilic Sulfate-Reducing Bacteria in Cold Marine Sediment

    DEFF Research Database (Denmark)

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

    1994-01-01

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

  19. Optimum Settings for a Compound Parabolic Concentrator with Wings Providing Increased Duration of Effective Temperature for Solar-Driven Systems: A Case Study for Tokyo

    Directory of Open Access Journals (Sweden)

    Muhammad Umair

    2013-12-01

    Full Text Available We designed a compound parabolic concentrator (CPC with wings angled toward the east and west. Normally, solar collectors are straight, facing south, and the effective temperature is only achieved for a short period of time at midday. In the proposed design, the collector is divided into three parts, with the ends angled and tilted at different orientations. The objective was to increase the duration of the effective temperature period by capturing the maximum solar energy in the morning and afternoon without tracking by the collector. A simulation model was developed to evaluate the performance of the proposed CPC. The tilt and bending angles of the CPC wings were optimized for year-round operation in Tokyo, Japan. A 35° tilt for the south-facing central part of the CPC and a 45° tilt for the wings with 50° angles toward the east and west were found to be optimal. Analyses were conducted at these optimum settings with temperatures of 70, 80, and 90 °C as minimum requirements. The effective duration increased by up to 2 h in the winter and up to 2.53 h in the summer using the proposed CPC. The proposed CPC will improve the efficiency of solar-driven systems by providing useful heat for longer periods of time with the same collector length and without the need for tracking.

  20. Molecular Characterization and Expression of a Phytase Gene from the Thermophilic Fungus Thermomyces lanuginosus

    Science.gov (United States)

    Berka, Randy M.; Rey, Michael W.; Brown, Kimberly M.; Byun, Tony; Klotz, Alan V.

    1998-01-01

    The phyA gene encoding an extracellular phytase from the thermophilic fungus Thermomyces lanuginosus was cloned and heterologously expressed, and the recombinant gene product was biochemically characterized. The phyA gene encodes a primary translation product (PhyA) of 475 amino acids (aa) which includes a putative signal peptide (23 aa) and propeptide (10 aa). The deduced amino acid sequence of PhyA has limited sequence identity (ca. 47%) with Aspergillus niger phytase. The phyA gene was inserted into an expression vector under transcriptional control of the Fusarium oxysporum trypsin gene promoter and used to transform a Fusarium venenatum recipient strain. The secreted recombinant phytase protein was enzymatically active between pHs 3 and 7.5, with a specific activity of 110 μmol of inorganic phosphate released per min per mg of protein at pH 6 and 37°C. The Thermomyces phytase retained activity at assay temperatures up to 75°C and demonstrated superior catalytic efficiency to any known fungal phytase at 65°C (the temperature optimum). Comparison of this new Thermomyces catalyst with the well-known Aspergillus niger phytase reveals other favorable properties for the enzyme derived from the thermophilic gene donor, including catalytic activity over an expanded pH range. PMID:9797301

  1. 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

  2. Mesophilic and thermophilic activated sludge post-treatment of paper mill process water

    NARCIS (Netherlands)

    Vogelaar, J.C.T.; Bouwhuis, E.; Klapwijk, A.; Spanjers, H.; Lier, van J.B.

    2002-01-01

    Increasing system closure in paper mills and higher process water temperatures make the applicability of thermophilic treatment systems increasingly important. The use of activated sludge as a suitable thermophilic post-treatment system for anaerobically pre-treated paper process water from a paper

  3. Discovery, cloning and characterisation of proline specific prolyl endopeptidase, a gluten degrading thermo-stable enzyme from Sphaerobacter thermophiles

    DEFF Research Database (Denmark)

    Shetty, Radhakrishna; Vestergaard, Mike; Jessen, Flemming

    2017-01-01

    processes occur at elevated temperature. We present in this paper, the discovery, cloning and characterisation of a novel recombinant thermostable gluten degrading enzyme, a proline specific prolyl endoprotease (PEP) from Sphaerobacter thermophiles. The molecular mass of the prolyl endopeptidase......Gluten free products have emerged during the last decades, as a result of a growing public concern and technological advancements allowing gluten reduction in food products. One approach is to use gluten degrading enzymes, typically at low or ambient temperatures, whereas many food production...... was estimated to be 77 kDa by using SDS-PAGE. Enzyme activity assays with a synthetic dipeptide Z-Gly-Pro-p-nitroanilide as the substrate revealed that the enzyme had optimal activity at pH 6.6 and was most active from pH 5.0-8.0. The optimum temperature was 63 °C and residual activity after one hour incubation...

  4. Thermophilic composting of municipal solid waste

    International Nuclear Information System (INIS)

    Elango, D.; Thinakaran, N.; Panneerselvam, P.; Sivanesan, S.

    2009-01-01

    Process of composting has been developed for recycling of organic fraction of municipal solid waste (MSW). The bioreactor design was modified to reduce the composting process time. The main goal of this investigation was to find the optimal value of time period for composting of MSW in thermophilic bioreactor under aerobic condition. The temperature profiles correlated well with experimental data obtained during the maturation process. During this period biological degraders are introduced in to the reactor to accelerate the composting process. The compost materials were analyzed at various stages and the environmental parameters were considered. The final composting materials contained large organic content with in a short duration of 40 days. The quantity of volume reduction of raw MSW was 78%. The test result shows that the final compost material from the thermophilic reactor provides good humus to build up soil characteristics and some basic plant nutrients

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-03-15

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

  6. ENDOSPORES OF THERMOPHILIC FERMENTATIVE BACTERIA

    DEFF Research Database (Denmark)

    Volpi, Marta

    2016-01-01

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

  7. 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

  8. Investigation of the Optimum Farming Temperature for Grifola frondosa and Growth Promotion using the Bio-Electric Potential as an Index

    Science.gov (United States)

    Yanagibashi, Hideyuki; Hirama, Junji; Matsuda, Masato; Miyamoto, Toshio

    The purpose of this study was to investigate the optimum farming conditions for mushrooms from the view point of engineering field. As the bio-electric potential of mushrooms is considered to be closely related to the activation of mushroom cells, this relationship has been used to analyze the dependence of the morphogenetic characteristics of Grifola frondosa on farming temperatures (from 16 to 22 degree C). The experimental results indicated that a maximum response was exhibited, with correspondingly favorable morphogenesis obtained at 18 degree C. Based on the experimental results, including those in a previous study, it was assumed that the larger the bio-electric potential becomes, the higher the growth yield reaches. In order to support this assumption, growth promotion was conducted by intentionally activating the bio-electric potential within the mushrooms by stimulating them with short bursts of illumination. The resulting observation of growth promotion permitted the conclusion that the bio-electric potential can, indeed, be regarded as an index of growth.

  9. The Optimum Feeding Frequency in Growing Korean Rockfish ( Rearing at the Temperature of 15°C and 19°C

    Directory of Open Access Journals (Sweden)

    Rahman Md Mizanur

    2014-09-01

    Full Text Available Two feeding trials were conducted to determine the optimum feeding frequency in growing Korean rockfish, (Sebastes schlegeli reared at the temperatures of 15°C and 19°C. Fish averaging 92.2±0.7 g (mean±standard deviation [SD] at 15.0±0.5°C and 100.2±0.4 g (mean±SD at 19.0±0.5°C water temperature were randomly distributed into each of 15 indoor tanks containing 250-L sea water from a semi-recirculation system. A total of five feeding frequency groups were set up in three replicates as follows: one meal in a day at 08:00 hour, two meals a day at 08:00 and 17:00 hours, three meals a day at 08:00, 14:00, and 20:00 hours, four meals a day at 08:00, 12:00, 16:00, and 20:00 hours, and one meal every 2 days at 08:00 hour. Fish were fed at the rate of 1.2% body weight (BW/d at 15°C and 1.5% BW/d at 19°C. At the end of 8 wks of feeding trial weight gain and specific growth rate were significantly higher at the fish fed groups of one meal a day and two meals a day at 15°C and fish fed groups of 1 meal every 2 days at 19°C were significantly lower than those of all other fish fed groups. Glutamic oxaloacetic transaminase and glutamic pyruvic transaminase of fish fed group at 1 meal every 2 days was significantly higher than those of all other fish fed groups in both experiments. Weight gain, specific growth rate and condition factor were gradually decreased as the feeding frequency increased. The results indicate that growing Korean rockfish 92 and 100 g perform better at 15°C than 19°C water temperature. As we expected, current results have indicated that a feeding frequency of 1 meal a day is optimal for the improvement of weight gain in growing Korean rockfish grown from 92 g to 133 g at 15°C and 100 g to 132 g at 19°C water temperature.

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

    DEFF Research Database (Denmark)

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

    2002-01-01

    The slate of the art of thermophilic digestion is discussed. Thermophilic digestion is a well established technology in Europe for treatment of mixtures of waste in common large scale biogas plants or for treatment of the organic fraction of municipal solid waste. Due to a large number of failures...... over time with thermophilic digestion of sewage sludge this process has lost its appeal in the USA. New demands on sanitation of biosolids before land use will, however, bring the attention back to the use of elevated temperatures during sludge stabilization. In the paper we show how the use of a start......-up strategy based on the actual activity of key microbes can be used to ensure proper and fast transfer of mesophilic digesters into thermophilic operation. Extreme thermophilic temperatures of 65degreesC or more may be necessary in the future to meet the demands for full sanitation of the waste material...

  11. Evaluation of Myceliopthora thermophila as an Enzyme Factory for the Production of Thermophilic Cellulolytic Enzymes

    Directory of Open Access Journals (Sweden)

    Leonidas Matsakas

    2015-07-01

    Full Text Available Enzymatic hydrolysis is a key step in bioethanol production. Efficient hydrolysis requires a consortium of different enzymes that are able to hydrolyze cellulose and hemicellulose into fermentable sugars. Myceliopthora thermophila is a promising candidate for the production of thermophilic cellulolytic enzymes, the use of which could reduce the cost of ethanol production. The growth conditions of the fungus were optimized in order to achieve increased secretion of extracellular cellulases. Optimal conditions were found to be 7.0% w/v brewer’s spent grain as the carbon source and 0.4% w/v ammonium sulfate as the nitrogen source. The cellulases obtained were characterized for their optimum activity. The optimum temperature and pH for cellulase activity are 65 °C and pH 5.5, respectively. Studies on thermal inactivation of the crude extract showed that the cellulases of M. thermophila are stable for temperatures up to 60 °C. At this temperature the half-life was found to be as high as 27 h. Enzymatic hydrolysis of cellulose resulted in 31.4% hydrolysis yield at 60 °C after 24 h of incubation. Finally, the recalcitrance constant for cellulose and cellulose pretreated with ionic liquids was calculated to be 5.46 and 2.69, respectively.

  12. Thermophilic xylanases: from bench to bottle.

    Science.gov (United States)

    Basit, Abdul; Liu, Junquan; Rahim, Kashif; Jiang, Wei; Lou, Huiqiang

    2018-01-17

    Lignocellulosic biomass is a valuable raw material. As technology has evolved, industrial interest in new ways to take advantage of this raw material has grown. Biomass is treated with different microbial cells or enzymes under ideal industrial conditions to produce the desired products. Xylanases are the key enzymes that degrade the xylosidic linkages in the xylan backbone of the biomass, and commercial enzymes are categorized into different glycoside hydrolase families. Thermophilic microorganisms are excellent sources of industrially relevant thermostable enzymes that can withstand the harsh conditions of industrial processing. Thermostable xylanases display high-specific activity at elevated temperatures and distinguish themselves in biochemical properties, structures, and modes of action from their mesophilic counterparts. Natural xylanases can be further improved through genetic engineering. Rapid progress with genome editing, writing, and synthetic biological techniques have provided unlimited potential to produce thermophilic xylanases in their natural hosts or cell factories including bacteria, yeasts, and filamentous fungi. This review will discuss the biotechnological potential of xylanases from thermophilic microorganisms and the ways they are being optimized and produced for various industrial applications.

  13. Thermophilic subseafloor microorganisms from the 1996 North Gorda Ridge eruption

    Science.gov (United States)

    Summit, Melanie; Baross, John A.

    1998-12-01

    High-temperature microbes were present in two hydrothermal event plumes (EP96A and B) resulting from the February-March 1996 eruptions along the North Gorda Ridge. Anaerobic thermophiles were cultured from 17 of 22 plume samples at levels exceeding 200 organisms per liter; no thermophiles were cultured from any of 12 samples of background seawater. As these microorganisms grow at temperatures of 50-90°C, they could not have grown in the event plume and instead most probably derived from a subseafloor environment tapped by the event plume source fluids. Event plumes are thought to derive from a pre-existing subseafloor fluid reservoir, which implies that these thermophiles are members of a native subseafloor community that was present before the eruptive event. Thermophiles also were cultured from continuous chronic-style hydrothermal plumes in April 1996; these plumes may have formed from cooling lava piles. To better understand the nutritional, chemical, and physical constraints of pre-eruptive crustal environments, seven coccoidal isolates from the two event plumes were partially characterized. Results from nutritional and phylogenetic studies indicate that these thermophiles are heterotrophic archaea that represent new species, and probably a new genus, within the Thermococcales.

  14. Thermophilic growth and enzymatic thermostability are polyphyletic traits within Chaetomiaceae.

    Science.gov (United States)

    van den Brink, Joost; Facun, Kryss; de Vries, Michel; Stielow, J Benjamin

    2015-12-01

    Thermophilic fungi have the potential to produce industrial-relevant thermostable enzymes, in particular for the degradation of plant biomass. Sordariales is one of the few fungal orders containing several thermophilic taxa, of which many have been associated with the production of thermostable enzymes. The evolutionary affiliation of Sordariales fungi, especially between thermophiles and non-thermophilic relatives, is however poorly understood. Phylogenetic analysis within the current study was based on sequence data, derived from a traditional Sanger and highly multiplexed targeted next generation sequencing approach of 45 isolates. The inferred phylogeny and detailed growth analysis rendered the trait 'thermophily' as polyphyletic within Chaetomiaceae (Sordariales, Sordariomycetes), and characteristic to: Myceliophthora spp., Thielavia terrestris, Chaetomium thermophilum, and Mycothermus thermophilus. Compared to mesophiles, the isolates within thermophilic taxa produced enzyme mixtures with the highest thermostability of known cellulase activities. Temperature profiles of the enzyme activities correlated strongly with the optimal growth temperatures of the isolates but not with their phylogenetic relationships. This strong correlation between growth and enzyme characteristics indicated that detailed analysis of growth does give predictive information on enzyme physiology. The variation in growth and enzyme characteristics reveals these fungi as an excellent platform to better understand fungal thermophily and enzyme thermostability. Copyright © 2015 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  15. In vitro production of thymine dimer by ultroviolet irradiation of DNA from mesophilic and thermophilic bacteria

    International Nuclear Information System (INIS)

    Yein, F.S.; Stenesh, J.

    1989-01-01

    Thymine dimer was produced in vitro by ultraviolet irradiation of DNA, isolated from the mesophile Bacillus licheniformis and the thermophile B. stearothermophilus. Irradiation was performed at three different temperaturs (35, 45 and 55 C) and the thymine dimer was isolated and determined. An HPLC procedure was developed that permitted temperature was greater for the thermophile than for the mesophile. Formation of thymine dimer increased with temperature for both organisms but more so for the thermophile; over the temperature range of 35-55 C, the average increase in thymine dimer production for the themrophile was about 4-times that for the mesophile. The melting out temperature, as a function of increasing irradiation temperature, was essentially unchanged for the mesophilic DNA, but decreased progressively for the thermophilic DNA. These results are discussed in terms of the macromolecular theory of to the macromolecular theory of the thermophily. (author). 31 refs.; 4 figs.; 3 tabs

  16. The cellulase activity of an extreme thermophile

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, J A [Meat Industry Research Inst. of New Zealand, Hamilton (New Zealand); Morgan, H W; Daniel, R M [Waikato Univ., Hamilton (New Zealand). Microbial Biochemistry and Biotechnology Unit

    1991-05-01

    The carboxymethylcellulase activity concentrated from the extremely thermophilic anaerobe H173 was found to have a pH optimum of 6.5-7.0. The enzyme activity was stabilised by the addition of dithiothreitol and CaCl{sub 2}.2H{sub 2}O and was very stable at 80deg C, retaining 77% of the inital activity after 120 min incubation. At 90deg C however, 50% activity remained after 9 min and after 120 min only 3% of the initial activity remained. With the enzyme dissolved in buffer, glucose and cellobiose were formed from the hydrolysis of Avicel. In culture medium the Avicel-solubilising activity was insensitive to the presence of up to 50 mM glucose and showed linear glucose accumulation over a period of days at 70deg C. HPLC analysis established that glucose was the major end-product of hydrolysis in the culture broths. (orig.).

  17. Structural studies on reaction centers from thermophilic photosynthetic bacteria and its functional utilizations. Tainetsusei kogosei saikin ni yuraisuru kogosei hanno chushin no kozo kaimei to kino kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Nozawa, T; Morishita, Y; Kobayashi, M; Kanno, S [Tohoku University, Sendai (Japan). Faculty of Engineering

    1992-10-31

    This paper describes the results of the experiment in which crystallization of protein of reactive center purified from the photosynthetic film of thermophilic purple sulfur photosynthetic bacterium Chromatium tepidum whose hyrogen donor in photosynthesis is H2S instead of H2O was attempted. Crystallization was carried out by the vapor diffusion method and particularly by using ethylene glycol as precipitator at 4[degree]C after various investigations on the conditions of crystallization. By X-ray diffraction, this crystal was found to belong to the rhombic system, and it was estimated that the lattice constants, a, b, c equal to 140[angstrom], 190[angstrom] and 80[angstrom] respectively. This bacterium is a thermophilic bacterium having the optimum growth temperature of 48-50 [degree]C and utilizes CO2 or H2CO3 as corbon source, ammonium, urea etc. as nitrogen source and thiosulfate as sulfur source. Moreover, another purpose of this investigation was to determine the thermophilic location by elucidating its configuration (although, as a result, the analysis of configuration had no sufficient resolution). It was confirmed that the enzyme system of photosynthetic film and its cytoplasm obtained by ultrasonic spallation of this cell have CO2 fixing activity utilizing light energy. 23 refs., 14 figs., 3 tabs.

  18. 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

    fermentation (24 h) and stopped at pH 4.5 due to the accumulation of organic acids. The maximum H(2) production yield and rate at sucrose concentration of 20 gl(-1), pH 6.25 and temperature 60 degrees C were 2.53 mol H(2) mol(-1) hexose and 12.12 mmol H(2) l(-1) h(-1), respectively. Organic nitrogen amended......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...... a high yield and production rate of H(2). Temperature optimum, pH optimum and substrate utilization for H(2) production were investigated in batch conditions. All of tested substrate was utilized for H(2) production, while sucrose, xylose and starch were the preferred substrates. The strain produced H(2...

  19. Extracellular production of avicelase by the thermophilic soil bacterium Bacillus sp. SMIA-2

    Directory of Open Access Journals (Sweden)

    Luciana Ribeiro Coutinho Oliveira

    2014-05-01

    Full Text Available Nowadays, the isolation of new bacterial strains that produce enzymes with novel properties is a subject of great relevance to the scientific community. This study, in order to search for producers of new cellulase strains, investigated the avicelase production by thermophilic Bacillus sp. strain SMIA-2. The best avicelase activity was observed in a culture medium containing 0.5% (w v-1 avicel and 0.5% (w v-1 corn steep liquor with initial pH 7.5-8.0 incubated at 50oC. When avicel was replaced in the medium by the treated sugarcane bagasse (0.5%, w v-1 the avicelase activity levels were not affected. Studies on the avicelase characterization revealed that the optimum pH of the enzyme was found to be 8.5 and the enzyme retained more than 80% of its activity after incubation at room temperature for 2h at pH 6.5-8.5. The optimum temperature of this enzyme was 70oC and the enzyme retained 67% of the original activity after 20 min. of heat treatment at 70oC. Avicelase was stimulated by Mn2+ and Co2+, whereas Hg2+ greatly inhibited the enzyme activity

  20. 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.

  1. Glycoside hydrolase activities of thermophilic bacterial consortia adapted to switchgrass.

    Science.gov (United States)

    Gladden, John M; Allgaier, Martin; Miller, Christopher S; Hazen, Terry C; VanderGheynst, Jean S; Hugenholtz, Philip; Simmons, Blake A; Singer, Steven W

    2011-08-15

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

  2. Ecology and biotechnological potential of the thermophilic fermentative Coprothermobacter spp.

    Science.gov (United States)

    Gagliano, M C; Braguglia, C M; Petruccioli, M; Rossetti, S

    2015-05-01

    Thermophilic bacteria have been isolated from several terrestrial, marine and industrial environments. Anaerobic digesters treating organic wastes are often an important source of these microorganisms, which catalyze a wide array of metabolic processes. Moreover, organic wastes are primarily composed of proteins, whose degradation is often incomplete. Coprothermobacter spp. are proteolytic anaerobic thermophilic microbes identified in several studies focused on the analysis of the microbial community structure in anaerobic thermophilic reactors. They are currently classified in the phylum Firmicutes; nevertheless, several authors showed that the Coprothermobacter group is most closely related to the phyla Dictyoglomi and Thermotoga. Since only a few proteolytic anaerobic thermophiles have been characterized so far, this microorganism has attracted the attention of researchers for its potential applications with high-temperature environments. In addition to proteolysis, Coprothermobacter spp. showed several metabolic abilities and may have a biotechnological application either as source of thermostable enzymes or as inoculum in anaerobic processes. Moreover, they can improve protein degradation by establishing a syntrophy with hydrogenotrophic archaea. To gain a better understanding of the phylogenesis, metabolic capabilities and adaptations of these microorganisms, it is of importance to better define the role in thermophilic environments and to disclose properties not yet investigated. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  3. Isolation of soil thermophilic strains of actinomycetes for the ...

    African Journals Online (AJOL)

    use

    2011-12-05

    Dec 5, 2011 ... to high fructose (Pandey et al., 2000; Asgher et al., 2007). *Corresponding ... can be increased by pH, temperature or substrates. ... The following media were used for isolating thermophilic strains of ... To observe the effect of different culture conditions on α-amylase .... Influence of pH on the inactivation of.

  4. Azo dye reduction by mesophilic and thermophilic anaerobic consortia

    NARCIS (Netherlands)

    Santos, dos A.B.; Madrid, de M.P.; Stams, A.J.M.; Lier, van J.B.; Cervantes, F.J.

    2005-01-01

    The reduction of the azo dye model compounds Reactive Red 2 (RR2) and Reactive Orange 14 (RO14) by mesophilic (30 C) and thermophilic (55 C) anaerobic consortia was studied in batch assays. The contribution of fermentative and methanogenic microorganisms in both temperatures was evaluated in the

  5. Nondissipative optimum charge regulator

    Science.gov (United States)

    Rosen, R.; Vitebsky, J. N.

    1970-01-01

    Optimum charge regulator provides constant level charge/discharge control of storage batteries. Basic power transfer and control is performed by solar panel coupled to battery through power switching circuit. Optimum controller senses battery current and modifies duty cycle of switching circuit to maximize current available to battery.

  6. (Hyper)thermophilic enzymes: production and purification.

    Science.gov (United States)

    Falcicchio, Pierpaolo; Levisson, Mark; Kengen, Servé W M; Koutsopoulos, Sotirios

    2014-01-01

    The discovery of thermophilic and hyperthermophilic microorganisms, thriving at environmental temperatures near or above 100 °C, has revolutionized our ideas about the upper temperature limit at which life can exist. The characterization of (hyper)thermostable proteins has broadened our understanding and presented new opportunities for solving one of the most challenging problems in biophysics: how is structural stability and biological function maintained at high temperatures where "normal" proteins undergo dramatic structural changes? In our laboratory we have purified and studied many thermostable and hyperthermostable proteins in an attempt to determine the molecular basis of heat stability. Here, we present methods to express such proteins and enzymes in E. coli and provide a general protocol for overproduction and purification. The ability to produce enzymes that retain their stability and activity at elevated temperatures creates exciting opportunities for a wide range of biocatalytic applications.

  7. Myceliophthora thermophila syn. Sporotrichum thermophile: a thermophilic mould of biotechnological potential.

    Science.gov (United States)

    Singh, Bijender

    2016-01-01

    Myceliophthora thermophila syn. Sporotrichum thermophile is a ubiquitous thermophilic mould with a strong ability to degrade organic matter during optimal growth at 45 °C. Both genome analysis and experimental data have suggested that the mould is capable of hydrolyzing all major polysaccharides found in biomass. The mould is able to secrete a large number of hydrolytic enzymes (cellulases, laccases, xylanases, pectinases, lipases, phytases and some other miscellaneous enzymes) employed in various biotechnological applications. Characterization of the biomass-hydrolyzing activity of wild and recombinant enzymes suggests that this mould is highly efficient in biomass decomposition at both moderate and high temperatures. The native enzymes produced by the mould are more efficient in activity than their mesophilic counterparts beside their low enzyme titers. The mould is able to synthesize various biomolecules, which are used in multifarious applications. Genome sequence data of M. thermophila also supported the physiological data. This review describes the biotechnological potential of thermophilic mould, M. thermophila supported by genomic and experimental evidences.

  8. Production and Characterization of an Extracellular Acid Protease from Thermophilic Brevibacillus sp. OA30 Isolated from an Algerian Hot Spring

    Directory of Open Access Journals (Sweden)

    Mohamed Amine Gomri

    2018-04-01

    Full Text Available Proteases have numerous biotechnological applications and the bioprospection for newly-thermostable proteases from the great biodiversity of thermophilic microorganisms inhabiting hot environments, such as geothermal sources, aims to discover more effective enzymes for processes at higher temperatures. We report in this paper the production and the characterization of a purified acid protease from strain OA30, a moderate thermophilic bacterium isolated from an Algerian hot spring. Phenotypic and genotypic study of strain OA30 was followed by the production of the extracellular protease in a physiologically-optimized medium. Strain OA30 showed multiple extracellular proteolytic enzymes and protease 32-F38 was purified by chromatographic methods and its biochemical characteristics were studied. Strain OA30 was affiliated with Brevibacillus thermoruber species. Protease 32-F38 had an estimated molecular weight of 64.6 kDa and was optimally active at 50 °C. It showed a great thermostability after 240 min and its optimum pH was 6.0. Protease 32-F38 was highly stable in the presence of different detergents and solvents and was inhibited by metalloprotease inhibitors. The results of this work suggest that protease 32-F38 might have interesting biotechnological applications.

  9. Production and Characterization of an Extracellular Acid Protease from Thermophilic Brevibacillus sp. OA30 Isolated from an Algerian Hot Spring.

    Science.gov (United States)

    Gomri, Mohamed Amine; Rico-Díaz, Agustín; Escuder-Rodríguez, Juan-José; El Moulouk Khaldi, Tedj; González-Siso, María-Isabel; Kharroub, Karima

    2018-04-12

    Proteases have numerous biotechnological applications and the bioprospection for newly-thermostable proteases from the great biodiversity of thermophilic microorganisms inhabiting hot environments, such as geothermal sources, aims to discover more effective enzymes for processes at higher temperatures. We report in this paper the production and the characterization of a purified acid protease from strain OA30, a moderate thermophilic bacterium isolated from an Algerian hot spring. Phenotypic and genotypic study of strain OA30 was followed by the production of the extracellular protease in a physiologically-optimized medium. Strain OA30 showed multiple extracellular proteolytic enzymes and protease 32-F38 was purified by chromatographic methods and its biochemical characteristics were studied. Strain OA30 was affiliated with Brevibacillus thermoruber species. Protease 32-F38 had an estimated molecular weight of 64.6 kDa and was optimally active at 50 °C. It showed a great thermostability after 240 min and its optimum pH was 6.0. Protease 32-F38 was highly stable in the presence of different detergents and solvents and was inhibited by metalloprotease inhibitors. The results of this work suggest that protease 32-F38 might have interesting biotechnological applications.

  10. NOAA Optimum Interpolation (OI) SST V2

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The optimum interpolation (OI) sea surface temperature (SST) analysis is produced weekly on a one-degree grid. The analysis uses in situ and satellite SST's plus...

  11. Sequence homolog-based molecular engineering for shifting the enzymatic pH optimum

    Directory of Open Access Journals (Sweden)

    Fuqiang Ma

    2016-09-01

    Full Text Available Cell-free synthetic biology system organizes multiple enzymes (parts from different sources to implement unnatural catalytic functions. Highly adaption between the catalytic parts is crucial for building up efficient artificial biosynthetic systems. Protein engineering is a powerful technology to tailor various enzymatic properties including catalytic efficiency, substrate specificity, temperature adaptation and even achieve new catalytic functions. However, altering enzymatic pH optimum still remains a challenging task. In this study, we proposed a novel sequence homolog-based protein engineering strategy for shifting the enzymatic pH optimum based on statistical analyses of sequence-function relationship data of enzyme family. By two statistical procedures, artificial neural networks (ANNs and least absolute shrinkage and selection operator (Lasso, five amino acids in GH11 xylanase family were identified to be related to the evolution of enzymatic pH optimum. Site-directed mutagenesis of a thermophilic xylanase from Caldicellulosiruptor bescii revealed that four out of five mutations could alter the enzymatic pH optima toward acidic condition without compromising the catalytic activity and thermostability. Combination of the positive mutants resulted in the best mutant M31 that decreased its pH optimum for 1.5 units and showed increased catalytic activity at pH < 5.0 compared to the wild-type enzyme. Structure analysis revealed that all the mutations are distant from the active center, which may be difficult to be identified by conventional rational design strategy. Interestingly, the four mutation sites are clustered at a certain region of the enzyme, suggesting a potential “hot zone” for regulating the pH optima of xylanases. This study provides an efficient method of modulating enzymatic pH optima based on statistical sequence analyses, which can facilitate the design and optimization of suitable catalytic parts for the construction

  12. Rapid establishment of thermophilic anaerobic microbial community during the one-step startup of thermophilic anaerobic digestion from a mesophilic digester.

    Science.gov (United States)

    Tian, Zhe; Zhang, Yu; Li, Yuyou; Chi, Yongzhi; Yang, Min

    2015-02-01

    The purpose of this study was to explore how fast the thermophilic anaerobic microbial community could be established during the one-step startup of thermophilic anaerobic digestion from a mesophilic digester. Stable thermophilic anaerobic digestion was achieved within 20 days from a mesophilic digester treating sewage sludge by adopting the one-step startup strategy. The succession of archaeal and bacterial populations over a period of 60 days after the temperature increment was followed by using 454-pyrosequencing and quantitative PCR. After the increase of temperature, thermophilic methanogenic community was established within 11 days, which was characterized by the fast colonization of Methanosarcina thermophila and two hydrogenotrophic methanogens (Methanothermobacter spp. and Methanoculleus spp.). At the same time, the bacterial community was dominated by Fervidobacterium, whose relative abundance rapidly increased from 0 to 28.52 % in 18 days, followed by other potential thermophilic genera, such as Clostridium, Coprothermobacter, Anaerobaculum and EM3. The above result demonstrated that the one-step startup strategy could allow the rapid establishment of the thermophilic anaerobic microbial community. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Geobacillus zalihae sp. nov., a thermophilic lipolytic bacterium isolated from palm oil mill effluent in Malaysia.

    Science.gov (United States)

    Abd Rahman, Raja Noor Zaliha Raja; Leow, Thean Chor; Salleh, Abu Bakar; Basri, Mahiran

    2007-08-10

    Thermophilic Bacillus strains of phylogenetic Bacillus rRNA group 5 were described as a new genus Geobacillus. Their geographical distribution included oilfields, hay compost, hydrothermal vent or soils. The members from the genus Geobacillus have a growth temperatures ranging from 35 to 78 degrees C and contained iso-branched saturated fatty acids (iso-15:0, iso-16:0 and iso-17:0) as the major fatty acids. The members of Geobacillus have similarity in their 16S rRNA gene sequences (96.5-99.2%). Thermophiles harboring intrinsically stable enzymes are suitable for industrial applications. The quest for intrinsically thermostable lipases from thermophiles is a prominent task due to the laborious processes via genetic modification. Twenty-nine putative lipase producers were screened and isolated from palm oil mill effluent in Malaysia. Of these, isolate T1T was chosen for further study as relatively higher lipase activity was detected quantitatively. The crude T1 lipase showed high optimum temperature of 70 degrees C and was also stable up to 60 degrees C without significant loss of crude enzyme activity. Strain T1T was a Gram-positive, rod-shaped, endospore forming bacterium. On the basic of 16S rDNA analysis, strain T1T was shown to belong to the Bacillus rRNA group 5 related to Geobacillus thermoleovorans (DSM 5366T) and Geobacillus kaustophilus (DSM 7263T). Chemotaxonomic data of cellular fatty acids supported the affiliation of strain T1T to the genus Geobacillus. The results of physiological and biochemical tests, DNA/DNA hybridization, RiboPrint analysis, the length of lipase gene and protein pattern allowed genotypic and phenotypic differentiation of strain T1T from its validly published closest phylogenetic neighbors. Strain T1T therefore represents a novel species, for which the name Geobacillus zalihae sp. nov. is proposed, with the type strain T1T (=DSM 18318T; NBRC 101842T). Strain T1T was able to secrete extracellular thermostable lipase into culture

  14. Geobacillus zalihae sp. nov., a thermophilic lipolytic bacterium isolated from palm oil mill effluent in Malaysia

    Directory of Open Access Journals (Sweden)

    Salleh Abu

    2007-08-01

    Full Text Available Abstract Background Thermophilic Bacillus strains of phylogenetic Bacillus rRNA group 5 were described as a new genus Geobacillus. Their geographical distribution included oilfields, hay compost, hydrothermal vent or soils. The members from the genus Geobacillus have a growth temperatures ranging from 35 to 78°C and contained iso-branched saturated fatty acids (iso-15:0, iso-16:0 and iso-17:0 as the major fatty acids. The members of Geobacillus have similarity in their 16S rRNA gene sequences (96.5–99.2%. Thermophiles harboring intrinsically stable enzymes are suitable for industrial applications. The quest for intrinsically thermostable lipases from thermophiles is a prominent task due to the laborious processes via genetic modification. Results Twenty-nine putative lipase producers were screened and isolated from palm oil mill effluent in Malaysia. Of these, isolate T1T was chosen for further study as relatively higher lipase activity was detected quantitatively. The crude T1 lipase showed high optimum temperature of 70°C and was also stable up to 60°C without significant loss of crude enzyme activity. Strain T1T was a Gram-positive, rod-shaped, endospore forming bacterium. On the basic of 16S rDNA analysis, strain T1T was shown to belong to the Bacillus rRNA group 5 related to Geobacillus thermoleovorans (DSM 5366T and Geobacillus kaustophilus (DSM 7263T. Chemotaxonomic data of cellular fatty acids supported the affiliation of strain T1T to the genus Geobacillus. The results of physiological and biochemical tests, DNA/DNA hybridization, RiboPrint analysis, the length of lipase gene and protein pattern allowed genotypic and phenotypic differentiation of strain T1T from its validly published closest phylogenetic neighbors. Strain T1T therefore represents a novel species, for which the name Geobacillus zalihae sp. nov. is proposed, with the type strain T1T (=DSM 18318T; NBRC 101842T. Conclusion Strain T1T was able to secrete extracellular

  15. Oxidative phosphorylation in a thermophilic, facultative chemoautotroph, Hydrogenophilus thermoluteolus, living prevalently in geothermal niches.

    Science.gov (United States)

    Wakai, Satoshi; Masanari, Misa; Ikeda, Takumi; Yamaguchi, Naho; Ueshima, Saori; Watanabe, Kaori; Nishihara, Hirofumi; Sambongi, Yoshihiro

    2013-04-01

    Hydrogenophilus is a thermophilic, facultative chemoautotroph, which lives prevalently in high temperature geothermal niches. Despite the environmental distribution, little is known about its oxidative phosphorylation. Here, we show that inverted membrane vesicles derived from Hydrogenophilus thermoluteolus cells autotrophically cultivated with H2 formed a proton gradient on the addition of succinate, dl-lactate, and NADH, and exhibited oxidation activity toward these three organic compounds. These indicate the capability of mixotrophic growth of this bacterium. Biochemical analysis demonstrated that the same vesicles contained an F-type ATP synthase. The F1 sector of the ATP synthase purified from H. thermoluteolus membranes exhibited optimal ATPase activity at 65°C. Transformed Escherichia coli membranes expressing H. thermoluteolus F-type ATP synthase exhibited the same temperature optimum for the ATPase. These findings shed light on H. thermoluteolus oxidative phosphorylation from the aspects of membrane bioenergetics and ATPase biochemistry, which must be fundamental and advantageous in the biogeochemical cycles occurred in the high temperature geothermal niches. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  16. Isolation and characterization of a radiation resistant thermophilic bacterium from radon hot spring

    International Nuclear Information System (INIS)

    Liang Xinle; Yang Long; Zhang Hong; Zhang Lei

    2011-01-01

    A radiation resistant and thermophilic bacterium strain R4-33 was isolated from radon hot spring water samples, pretreated with 60 Co γ-rays and UV irradiation. Tests on morphological, physiological and biochemical characters, fatty acid compositions, (G + C) mol% contents, and 16S rDNA sequencing were conducted. The results showed that strain R4-33 was of rod-shape, Gram-negative, atrichous, and endospore-forming. The optimum growth temperature and pH were 60 ℃ and 7.5, respectively. The strain utilized glucose, maltose and trehalose as carbon sources, and hydrolyzed casein and starch. Its catalase positive. The strain was sensitive to penicillin, neomycin, erythromycin, vancomycin, streptomycin, gentamycin, amikacin and ampicillin. The major cellular fatty acids were C 14:1 (48.8%) and C 15:1 (15.2%). The (G + C) mol% content of DNA was 58.2%. Phylogenetic tree based on 16S rDNA sequence showed R4-33 shared highly similarity to those of species in genus Anoxybacillus, especially to that of Anoxybacillus gonensis (99.5%). Based on the above, the strain R4-33 was proposed to the evolution branch of Anoxybacillus and designated as Anoxybacillu sp. R4-33. The UV and γ-radiation tests showed that the strain R4-33 had an ability of resistance to UV of 396 J/m 2 and 60 Co γ-rays irradiation of 14.0 kGy, indicating that the strain was a radiation resistant and thermophilic bacterium. (authors)

  17. In vitro bioconversion of chitin to pyruvate with thermophilic enzymes.

    Science.gov (United States)

    Honda, Kohsuke; Kimura, Keisuke; Ninh, Pham Huynh; Taniguchi, Hironori; Okano, Kenji; Ohtake, Hisao

    2017-09-01

    Chitin is the second most abundant organic compound on the planet and thus has been regarded as an alternative resource to petroleum feedstocks. One of the key challenges in the biological conversion of biomass-derived polysaccharides, such as cellulose and chitin, is to close the gap between optimum temperatures for enzymatic saccharification and microbial fermentation and to implement them in a single bioreactor. To address this issue, in the present study, we aimed to perform an in vitro, one-pot bioconversion of chitin to pyruvate, which is a precursor of a wide range of useful metabolites. Twelve thermophilic enzymes, including that for NAD + regeneration, were heterologously produced in Escherichia coli and semi-purified by heat treatment of the crude extract of recombinant cells. When the experimentally decided concentrations of enzymes were incubated with 0.5 mg mL -1 colloidal chitin (equivalent to 2.5 mM N-acetylglucosamine unit) and an adequate set of cofactors at 70°C, 0.62 mM pyruvate was produced in 5 h. Despite the use of a cofactor-balanced pathway, determination of the pool sizes of cofactors showed a rapid decrease in ATP concentration, most probably due to the thermally stable ATP-degrading enzyme(s) derived from the host cell. Integration of an additional enzyme set of thermophilic adenylate kinase and polyphosphate kinase led to the deceleration of ATP degradation, and the final product titer was improved to 2.1 mM. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  18. Structural and physicochemical properties of polar lipids from thermophilic archaea.

    Science.gov (United States)

    Ulrih, Natasa Poklar; Gmajner, Dejan; Raspor, Peter

    2009-08-01

    The essential general features required for lipid membranes of extremophilic archaea to fulfill biological functions are that they are in the liquid crystalline phase and have extremely low permeability of solutes that is much less temperature sensitive due to a lack of lipid-phase transition and highly branched isoprenoid chains. Many accumulated data indicate that the organism's response to extremely low pH is the opposite of that to high temperature. The high temperature adaptation does not require the tetraether lipids, while the adaptation of thermophiles to acidic environment requires the tetraether polar lipids. The presence of cyclopentane rings and the role of polar heads are not so straightforward regarding the correlations between fluidity and permeability of the lipid membrane. Due to the unique lipid structures and properties of archaeal lipids, they are a valuable resource in the development of novel biotechnological processes. This microreview focuses primarily on structural and physicochemical properties of polar lipids of (hyper)thermophilic archaea.

  19. Evolvability of thermophilic proteins from archaea and bacteria.

    Science.gov (United States)

    Takano, Kazufumi; Aoi, Atsushi; Koga, Yuichi; Kanaya, Shigenori

    2013-07-16

    Proteins from thermophiles possess high thermostability. The stabilization mechanisms differ between archaeal and bacterial proteins, whereby archaeal proteins are mainly stabilized via hydrophobic interactions and bacterial proteins by ion pairs. High stability is an important factor in promoting protein evolution, but the precise means by which different stabilization mechanisms affect the evolution process remain unclear. In this study, we investigated a random mutational drift of esterases from thermophilic archaea and bacteria at high temperatures. Our results indicate that mutations in archaeal proteins lead to improved function with no loss of stability, while mutant bacterial proteins are largely destabilized with decreased activity at high temperatures. On the basis of these findings, we suggest that archaeal proteins possess higher "evolvability" than bacterial proteins under temperature selection and are additionally able to evolve into eukaryotic proteins.

  20. Complete genome sequence of the thermophilic sulfur-reducer Desulfurobacterium thermolithotrophum type strain (BSAT) from a deep-sea hydrothermal vent

    Energy Technology Data Exchange (ETDEWEB)

    Goker, Markus [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Daligault, Hajnalka E. [Los Alamos National Laboratory (LANL); Mwirichia, Romano [Jomo Kenyatta University of Agriculture and Technology, Nairobi, Kenya; Lapidus, Alla L. [U.S. Department of Energy, Joint Genome Institute; Deshpande, Shweta [U.S. Department of Energy, Joint Genome Institute; Pagani, Ioanna [U.S. Department of Energy, Joint Genome Institute; Tapia, Roxanne [Los Alamos National Laboratory (LANL); Cheng, Jan-Fang [U.S. Department of Energy, Joint Genome Institute; Goodwin, Lynne A. [Los Alamos National Laboratory (LANL); Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Liolios, Konstantinos [U.S. Department of Energy, Joint Genome Institute; Ivanova, N [U.S. Department of Energy, Joint Genome Institute; Mavromatis, K [U.S. Department of Energy, Joint Genome Institute; Mikhailova, Natalia [U.S. Department of Energy, Joint Genome Institute; Pati, Amrita [U.S. Department of Energy, Joint Genome Institute; Chen, Amy [U.S. Department of Energy, Joint Genome Institute; Palaniappan, Krishna [U.S. Department of Energy, Joint Genome Institute; Han, Cliff [Los Alamos National Laboratory (LANL); Land, Miriam L [ORNL; Hauser, Loren John [ORNL; Pan, Chongle [ORNL; Brambilla, Evelyne-Marie [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Rohde, Manfred [HZI - Helmholtz Centre for Infection Research, Braunschweig, Germany; Spring, Stefan [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Sikorski, Johannes [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany; Wirth, Reinhard [Universitat Regensburg, Regensburg, Germany; Detter, J. Chris [U.S. Department of Energy, Joint Genome Institute; Woyke, Tanja [U.S. Department of Energy, Joint Genome Institute; Bristow, James [U.S. Department of Energy, Joint Genome Institute; Eisen, Jonathan [U.S. Department of Energy, Joint Genome Institute; Markowitz, Victor [U.S. Department of Energy, Joint Genome Institute; Hugenholtz, Philip [U.S. Department of Energy, Joint Genome Institute; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Klenk, Hans-Peter [DSMZ - German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany

    2011-01-01

    Desulfurobacterium thermolithotrophum L'Haridon et al. 1998 is the type species of the ge- nus Desulfurobacterium which belongs to the family Desulfurobacteriaceae. The species is of interest because it represents the first thermophilic bacterium that can act as a primary pro- ducer in the temperature range of 45-75 C (optimum 70 C) and is incapable of growing un- der microaerophilic conditions. Strain BSAT preferentially synthesizes high-melting-point fatty acids (C18 and C20) which is hypothesized to be a strategy to ensure the functionality of the membrane at high growth temperatures. This is the second completed genome sequence of a member of the family Desulfurobacteriaceae and the first sequence from the genus Desulfu- robacterium. The 1,541,968 bp long genome harbors 1,543 protein-coding and 51 RNA genes and is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

  1. Effect of pH, Temperature, and Chemicals on the Endoglucanases and β-Glucosidases from the Thermophilic Fungus Myceliophthora heterothallica F.2.1.4. Obtained by Solid-State and Submerged Cultivation

    Directory of Open Access Journals (Sweden)

    Vanessa de Cássia Teixeira da Silva

    2016-01-01

    Full Text Available This work reports endoglucanase and beta-glucosidase production by the thermophilic fungus Myceliophthora heterothallica in solid-state (SSC and submerged (SmC cultivation. Wheat bran and sugarcane bagasse were used for SSC and cardboard for SmC. Highest endoglucanase production in SSC occurred after 192 hours: 1,170.6 ± 0.8 U/g, and in SmC after 168 hours: 2,642 ± 561 U/g. The endoglucanases and beta-glucosidases produced by both cultivation systems showed slight differences concerning their optimal pH and temperature. The number of endoglucanases was also different: six isoforms in SSC and ten in SmC. Endoglucanase activity remained above 50% after incubation between pH 3.0 and 9.0 for 24 h for both cultivation systems. The effect of several chemicals displayed variation between SSC and SmC isoenzymes. Manganese activated the enzymes from SmC but inhibited those from SSC. For β-glucosidases, maximum production on SmC was 244 ± 48 U/g after 168 hours using cardboard as carbon source. In SSC maximum production reached 10.9 ± 0.3 U/g after 240 h with 1 : 1 wheat bran and sugarcane bagasse. Manganese exerted a significant activation on SSC β-glucosidases, and glucose inhibited the enzymes from both cultivation systems. FeCl3 exerted the strongest inhibition for endoglucanases and β-glucosidases.

  2. Startup and stability of thermophilic anaerobic digestion of OFMSW

    KAUST Repository

    El-Fadel, Mutasem E.; Saikaly, Pascal; Ghanimeh, Sophia A.

    2013-01-01

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

  3. On Optimum Stratification

    OpenAIRE

    M. G. M. Khan; V. D. Prasad; D. K. Rao

    2014-01-01

    In this manuscript, we discuss the problem of determining the optimum stratification of a study (or main) variable based on the auxiliary variable that follows a uniform distribution. If the stratification of survey variable is made using the auxiliary variable it may lead to substantial gains in precision of the estimates. This problem is formulated as a Nonlinear Programming Problem (NLPP), which turn out to multistage decision problem and is solved using dynamic programming technique.

  4. Evaluation of microbial community composition in thermophilic methane-producing incubation of production water from a high-temperature oil reservoir.

    Science.gov (United States)

    Zhou, Fang; Mbadinga, Serge Maurice; Liu, Jin-Feng; Gu, Ji-Dong; Mu, Bo-Zhong

    2013-01-01

    Investigation of petroleum microbes is fundamental for the development and utilization of oil reservoirs' microbial resources, and also provides great opportunities for research and development of bio-energy. Production water from a high-temperature oil reservoir was incubated anaerobically at 55 degrees C for more than 400 days without amendment of any nutrients. Over the time of incubation, about 1.6 mmol of methane and up to 107 micromol of hydrogen (H2) were detected in the headspace. Methane formation indicated that methanogenesis was likely the predominant process in spite of the presence of 23.4 mM SO4(2-) in the production water. Microbial community composition of the incubation was characterized by means of 16S rRNA gene clone libraries construction. Bacterial composition changed from Pseudomonales as the dominant population initially to Hydrogenophilales-related microorganisms affiliated to Petrobacter spp. closely. After 400 days of incubation, other bacterial members detected were related to Anareolineales, beta-, gamma-, and delta-Proteobacteria. The archaeal composition of the original production water was essentially composed of obligate acetoclastic methanogens of the genus Methanosaeta, but the incubation was predominantly composed of CO2-reducing methanogens of the genus Methanothermobacter and Crenarchaeotes-related microorganisms. Our results suggest that methanogenesis could be more active than expected in oil reservoir environments and methane formation from CO2-reduction played a significant role in the methanogenic community. This conclusion is consistent with the predominant role played by H2-oxidizing methanogens in the methanogenic conversion of organic matter in high-temperature petroleum reservoirs.

  5. Determination of the optimum contribution of Brahman genetics in an Angus-Brahman multibreed herd for regulation of body temperature during hot weather.

    Science.gov (United States)

    Dikmen, Serdal; Mateescu, Raluca G; Elzo, Mauricio A; Hansen, Peter J

    2018-06-04

    The objective was to evaluate the influence of varying amounts of Brahman genetics on body temperature under pasture conditions during hot weather. Vaginal temperatures were measured at 5-min intervals for 3 to 5 d on four occasions during August and September from a total of 190 pregnant cows that were either Angus, 2/8 Brahman (remainder Angus), Brangus (3/8 Brahman), 4/8 Brahman, 6/8 Brahman or Brahman. Vaginal temperature was higher for the first two replicates than for the second two replicates. In the first two replicates, average vaginal temperature did not differ between genetic groups, but average vaginal temperature from 1500 to 1900 h was lower for Brahman than other groups. In the second two replicates, average vaginal temperature was lower for cows that were 4/8 or higher Brahman than for cows that were 2/8 Brahman or Angus. Average vaginal temperature from 1500 to 1900 h was lower for cows that were 4/8 or higher Brahman than for cows that were 2/8 Brahman or Angus. In addition, Brahman cows had lower vaginal temperatures than cows that were 4/8 Brahman or 3/8 Brahman (i.e., Brangus). In one replicate, a tracking device was used to map cow location. At 1200 to 1300 h, cows that were 6/8 Brahman or Brahman had fewer observations near the tree line (i.e., in shade) than cows that were 4/8 Brahman or less. At 1500 to 1600 h, cows that were 4/8 or higher Brahman experienced fewer observations near the tree line than cows that contained a lower fraction of Brahman genetics. In summary, a minimum of 4/8 Brahman genetics was required to increase the ability to regulate body temperature and at least 6/8 Brahman when heat stress was severe. It is likely, therefore, that using Brahman genetics to optimize adaptation to thermal stress under conditions of severe heat stress requires a preponderance of Brahman genes.

  6. Anaerobic thermophilic culture-system

    Energy Technology Data Exchange (ETDEWEB)

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

    1981-04-14

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

  7. Diversity of Cultured Thermophilic Anaerobes in Hot Springs of Yunnan Province, China

    Science.gov (United States)

    Lin, L.; Lu, Y.; Dong, X.; Liu, X.; Wei, Y.; Ji, X.; Zhang, C.

    2010-12-01

    Thermophilic anaerobes including Archaea and Bacteria refer to those growing optimally at temperatures above 50°C and do not use oxygen as the terminal electron acceptor for growth. Study on thermophilic anaerobes will help to understand how life thrives under extreme conditions. Meanwhile thermophilic anaerobes are of importance in potential application and development of thermophilic biotechnology. We have surveyed culturable thermophilic anaerobes in hot springs (pH6.5-7.5; 70 - 94°C) in Rehai of Tengchong, Bangnazhang of Longlin, Eryuan of Dali,Yunnan, China. 50 strains in total were cultured from the hot springs water using Hungate anaerobic technique, and 30 strains were selected based on phenotypic diversity for analysis of 16S rDNA sequences. Phylogenetic analysis showed that 28 strains belonged to the members of five genera: Caldanaerobacter, Calaramator, Thermoanaerobacter, Dictyoglomus and Fervidobacterium, which formed five branches on the phylogenetic tree. Besides, 2 strains of methanogenic archaea were obtained. The majority of the isolates were the known species, however, seven strains were identified as novel species affiliated to the five genera based on the lower 16S rDNA sequence similarities (less than 93 - 97%) with the described species. This work would provide the future study on their diversity, distribution among different regions and the potential application of thermophilic enzyme. Supported by State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences(SKLMR-080605)and the Foundation of State Natural Science (30660009, 30960022, 31081220175).

  8. Optimum temperature of a northern population of Arctic charr (Salvelinus alpinus) using heart rate Arrhenius breakpoint analysis

    DEFF Research Database (Denmark)

    Hansen, Aslak Kappel; Byriel, David Bille; R. Jensen, Mads

    2017-01-01

    ± 0.4). The Q10 breakpoint occurred at an average of 7.1 °C ± 0.3. There was no significant difference between the breakpoint temperature found using Q10 and Arrhenius [two-sample t test, df = 16; p > 0.1]. The highest fHmax was found at 12.8 °C ± 1.0 reaching an average of 61.8 BPM ± 3.1. Arrhythmia...

  9. A thermophilic membrane bioreactor for treating and re-using paper mill effluent; Biorreactor de membrana termofilico para el tratamiento y reutilizacion de efluentes de papelera

    Energy Technology Data Exchange (ETDEWEB)

    Lopetegui Garnika, J.; Sancho Seuma, L.; Abad Oliva, A.

    2002-07-01

    Thermophilic operation of a membrane bioreactor offers many advantages; biodegradation rates increase with temperature and flux is higher because of water viscosity decrease. Therefore,poor sttleability related to thermophilic sludges is solved by ultrafiltration and a suspended solids and turbidity free effluent is obtained. That suppose a wider range of applications interns of water reuse. (Author) 18 refs.

  10. Extremely Thermophilic Microorganisms as Metabolic Engineering Platforms for Production of Fuels and Industrial Chemicals

    Directory of Open Access Journals (Sweden)

    Benjamin M Zeldes

    2015-11-01

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

  11. 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

  12. Growth and glucoamylase production by the thermophilic fungus Thermomyces lanuginosus in a synthetic medium

    Energy Technology Data Exchange (ETDEWEB)

    Haasum, I; Eriksen, S H; Jensen, B; Olsen, J [Copenhagen Univ. (Denmark). Dept. of General Microbiology

    1991-02-01

    The production of glucogenic amylase from the thermophilic fungus Thermomyces lanuginosus was studied in shake flasks and laboratory fermentors. As conidia were not able to germinate in media without yeast extract, pregerminated conidia were applied as inoculum. By this procedure it was possible to use different NH{sub 4}{sup +} salts as the sole source of nitrogen for growth and amylase formation in a synthetic medium. In pH-controlled fermentors a fourfold increase in the extracellular glucogenic amylase activity was obtained with (NH{sub 4})H{sub 2}PO{sub 4} as the nitrogen source as compared with yeast extract. However, by fractionation of these activities, comparable yields of partially purified glucoamylases were obtained. The glucoamylase preparation from fermentations with either of the nitrogen sources had a temperature optimum at 70deg C and showed similar thermal stability. By incubation without substrate at 60deg C, 90% of the activity was still present after 5 h. At 70deg C, 50% of the activity was retained after 30 min incubation. (orig.).

  13. The optimum spanning catenary cable

    Science.gov (United States)

    Wang, C. Y.

    2015-03-01

    A heavy cable spans two points in space. There exists an optimum cable length such that the maximum tension is minimized. If the two end points are at the same level, the optimum length is 1.258 times the distance between the ends. The optimum lengths for end points of different heights are also found.

  14. Choosing the optimum burnup

    International Nuclear Information System (INIS)

    Geller, L.; Goldstein, L.; Franks, W.A.

    1986-01-01

    This paper reviews some of the considerations utilities must evaluate when going to higher discharge burnups. The advantages and disadvantages of higher discharge burnups are described, as well as a consistent approach for evaluating optimum discharge burnup and its comparison to current practice. When an analysis is performed over the life of the plant, the design of the terminal cycles has significant impact on the lifetime savings from higher burnups. Designs for high burnup cycles have a greater average inventory value in the core. As one goes to higher burnup, there is a greater likelihood of discarding a larger value in unused fuel unless the terminal cycles are designed carefully. This effect can be large enough in some cases to wipe out the lifetime cost savings relative to operating with a higher discharge burnup cycle

  15. Review of optimum temperature, humidity, and vapour pressure deficit for microclimate evaluation and control in greenhouse cultivation of tomato: a review

    Science.gov (United States)

    Shamshiri, Redmond Ramin; Jones, James W.; Thorp, Kelly R.; Ahmad, Desa; Man, Hasfalina Che; Taheri, Sima

    2018-04-01

    Greenhouse technology is a flexible solution for sustainable year-round cultivation of Tomato (Lycopersicon esculentum Mill), particularly in regions with adverse climate conditions or limited land and resources. Accurate knowledge about plant requirements at different growth stages, and under various light conditions, can contribute to the design of adaptive control strategies for a more cost-effective and competitive production. In this context, different scientific publications have recommended different values of microclimate parameters at different tomato growth stages. This paper provides a detailed summary of optimal, marginal and failure air and root-zone temperatures, relative humidity and vapour pressure deficit for successful greenhouse cultivation of tomato. Graphical representations of the membership function model to define the optimality degrees of these three parameters are included with a view to determining how close the greenhouse microclimate is to the optimal condition. Several production constraints have also been discussed to highlight the short and long-term effects of adverse microclimate conditions on the quality and yield of tomato, which are associated with interactions between suboptimal parameters, greenhouse environment and growth responses.

  16. Potential and utilization of thermophiles and thermostable enzymes in biorefining

    Directory of Open Access Journals (Sweden)

    Karlsson Eva

    2007-03-01

    Full Text Available Abstract In today's world, there is an increasing trend towards the use of renewable, cheap and readily available biomass in the production of a wide variety of fine and bulk chemicals in different biorefineries. Biorefineries utilize the activities of microbial cells and their enzymes to convert biomass into target products. Many of these processes require enzymes which are operationally stable at high temperature thus allowing e.g. easy mixing, better substrate solubility, high mass transfer rate, and lowered risk of contamination. Thermophiles have often been proposed as sources of industrially relevant thermostable enzymes. Here we discuss existing and potential applications of thermophiles and thermostable enzymes with focus on conversion of carbohydrate containing raw materials. Their importance in biorefineries is explained using examples of lignocellulose and starch conversions to desired products. Strategies that enhance thermostablity of enzymes both in vivo and in vitro are also assessed. Moreover, this review deals with efforts made on developing vectors for expressing recombinant enzymes in thermophilic hosts.

  17. Comparing Residue Clusters from Thermophilic and Mesophilic Enzymes Reveals Adaptive Mechanisms.

    Directory of Open Access Journals (Sweden)

    Deanne W Sammond

    Full Text Available Understanding how proteins adapt to function at high temperatures is important for deciphering the energetics that dictate protein stability and folding. While multiple principles important for thermostability have been identified, we lack a unified understanding of how internal protein structural and chemical environment determine qualitative or quantitative impact of evolutionary mutations. In this work we compare equivalent clusters of spatially neighboring residues between paired thermophilic and mesophilic homologues to evaluate adaptations under the selective pressure of high temperature. We find the residue clusters in thermophilic enzymes generally display improved atomic packing compared to mesophilic enzymes, in agreement with previous research. Unlike residue clusters from mesophilic enzymes, however, thermophilic residue clusters do not have significant cavities. In addition, anchor residues found in many clusters are highly conserved with respect to atomic packing between both thermophilic and mesophilic enzymes. Thus the improvements in atomic packing observed in thermophilic homologues are not derived from these anchor residues but from neighboring positions, which may serve to expand optimized protein core regions.

  18. Comparing Residue Clusters from Thermophilic and Mesophilic Enzymes Reveals Adaptive Mechanisms.

    Science.gov (United States)

    Sammond, Deanne W; Kastelowitz, Noah; Himmel, Michael E; Yin, Hang; Crowley, Michael F; Bomble, Yannick J

    2016-01-01

    Understanding how proteins adapt to function at high temperatures is important for deciphering the energetics that dictate protein stability and folding. While multiple principles important for thermostability have been identified, we lack a unified understanding of how internal protein structural and chemical environment determine qualitative or quantitative impact of evolutionary mutations. In this work we compare equivalent clusters of spatially neighboring residues between paired thermophilic and mesophilic homologues to evaluate adaptations under the selective pressure of high temperature. We find the residue clusters in thermophilic enzymes generally display improved atomic packing compared to mesophilic enzymes, in agreement with previous research. Unlike residue clusters from mesophilic enzymes, however, thermophilic residue clusters do not have significant cavities. In addition, anchor residues found in many clusters are highly conserved with respect to atomic packing between both thermophilic and mesophilic enzymes. Thus the improvements in atomic packing observed in thermophilic homologues are not derived from these anchor residues but from neighboring positions, which may serve to expand optimized protein core regions.

  19. A family 5 β-mannanase from the thermophilic fungus Thielavia arenaria XZ7 with typical thermophilic enzyme features.

    Science.gov (United States)

    Lu, Haiqiang; Zhang, Huitu; Shi, Pengjun; Luo, Huiying; Wang, Yaru; Yang, Peilong; Yao, Bin

    2013-09-01

    A novel β-mannanase gene, man5XZ7, was cloned from thermophilic fungus Thielavia arenaria XZ7, and successfully expressed in Pichia pastoris. The gene (1,110 bp) encodes a 369-amino acid polypeptide with a molecular mass of approximately 40.8 kDa. The deduced sequence of Man5XZ7 consists of a putative 17-residue signal peptide and a catalytic module belonging to glycoside hydrolase (GH) family 5, and displays 76 % identity with the experimentally verified GH 5 endo-β-1,4-mannanase from Podospora anserina. Recombinant Man5XZ7 was optimally active at 75 °C and pH 5.0 and exhibited high activity at a wide temperature range (>50.0 % activity at 50-85 °C). Moreover, it had good adaptability to acidic to basic pH (>74.1 % activity at pH 4.0-7.0 and 25.6 % even at pH 9.0) and good stability from pH 3.0 to 10.0. These enzymatic properties showed that Man5XZ7 was a new thermophilic and alkali-tolerant β-mannanase. Further amino acid composition analysis indicated that Man5XZ7 has several characteristic features of thermophilic enzymes.

  20. Determination of the Morphology of the Starch Granules and the Optimum Internal Cooking Temperature of Four Andean Crops: Oca (Oxalis tuberosa Molina, Olluco (Ullucus tuberosus Loz, Isaño (Tropaeolum tuberosum Ruiz

    Directory of Open Access Journals (Sweden)

    Bellido-Valencia Omar

    2017-12-01

    Full Text Available Andean grains (i.e. quinoa, amaranth have been increasingly studied in recent times, mainly due to the increase in international consumption. However, Andean tubers other than potatoes have not been so widespread and are mainly studied for their starch, previously extracted. This work studied the morphology of native starch in four of these crops (oca, olluco, isaño and aracacha, during cooking and the evolution of their internal temperature in relation to sensory acceptability. Using scanning electron microscopy, it was determined that the size of crude starch granules was between 9 μm to 38.2 μm for oca, 4.48 to 24.9 μm for olluco, 4.45 to 22.9 μm for isaño, and 5.36 to 23.8 μm for arracacha. Sensorially, it was determined that the optimum cooking temperature for arracacha was 89.1°C, 90.9°C for oca, 91°C for isaño, and 91.4 °C for olluco. All samples had optimal cooking times shorter than potato, with the isaño having the best heat transfer.

  1. Functional expression of a penicillin acylase from the extreme thermophile Thermus thermophilus HB27 in Escherichia coli.

    Science.gov (United States)

    Torres, Leticia L; Ferreras, Eloy R; Cantero, Angel; Hidalgo, Aurelio; Berenguer, José

    2012-08-09

    Penicillin acylases (PACs) are enzymes of industrial relevance in the manufacture of β-lactam antibiotics. Development of a PAC with a longer half-life under the reaction conditions used is essential for the improvement of the operational stability of the process. A gene encoding a homologue to Escherichia coli PAC was found in the genome of the thermophilic bacterium Thermus thermophilus (Tth) HB27. Because of the nature of this PAC and its complex maturation that is crucial to reach its functional heterodimeric final conformation, the overexpression of this enzyme in a heterologous mesophilic host was a challenge. Here we describe the purification and characterization of the PAC protein from Tth HB27 overexpressed in Escherichia coli. Fusions to a superfolder green fluorescent protein and differential membrane solubilization assays indicated that the native enzyme remains attached through its amino-terminal end to the outer side of the cytoplasmic membrane of Tth cells. In order to overexpress this PAC in E. coli cells, a variant of the protein devoid of its membrane anchoring segment was constructed. The effect of the co-expression of chaperones and calcium supplementation of the culture medium was investigated. The total production of PAC was enhanced by the presence of DnaK/J and GrpE and even more by trigger factor and GroEL/ES. In addition, 10 mM calcium markedly improved both PAC specific and volumetric activities. Recombinant PAC was affinity-purified and proper maturation of the protein was confirmed by SDS-PAGE and MALDI-TOF analysis of the subunits. The recombinant protein was tested for activity towards several penicillins, cephalosporins and homoserine lactones. Hydrophobic acyl-chain penicillins were preferred over the rest of the substrates. Penicillin K (octanoyl penicillin) was the best substrate, with the highest specificity constant value (16.12 mM-1.seg-1). The optimum pH was aprox. 4 and the optimum temperature was 75 °C. The half-life of

  2. Functional expression of a penicillin acylase from the extreme thermophile Thermus thermophilus HB27 in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Torres Leticia L

    2012-08-01

    Full Text Available Abstract Background Penicillin acylases (PACs are enzymes of industrial relevance in the manufacture of β-lactam antibiotics. Development of a PAC with a longer half-life under the reaction conditions used is essential for the improvement of the operational stability of the process. A gene encoding a homologue to Escherichia coli PAC was found in the genome of the thermophilic bacterium Thermus thermophilus (Tth HB27. Because of the nature of this PAC and its complex maturation that is crucial to reach its functional heterodimeric final conformation, the overexpression of this enzyme in a heterologous mesophilic host was a challenge. Here we describe the purification and characterization of the PAC protein from Tth HB27 overexpressed in Escherichia coli. Results Fusions to a superfolder green fluorescent protein and differential membrane solubilization assays indicated that the native enzyme remains attached through its amino-terminal end to the outer side of the cytoplasmic membrane of Tth cells. In order to overexpress this PAC in E. coli cells, a variant of the protein devoid of its membrane anchoring segment was constructed. The effect of the co-expression of chaperones and calcium supplementation of the culture medium was investigated. The total production of PAC was enhanced by the presence of DnaK/J and GrpE and even more by trigger factor and GroEL/ES. In addition, 10 mM calcium markedly improved both PAC specific and volumetric activities. Recombinant PAC was affinity-purified and proper maturation of the protein was confirmed by SDS-PAGE and MALDI-TOF analysis of the subunits. The recombinant protein was tested for activity towards several penicillins, cephalosporins and homoserine lactones. Hydrophobic acyl-chain penicillins were preferred over the rest of the substrates. Penicillin K (octanoyl penicillin was the best substrate, with the highest specificity constant value (16.12 mM-1.seg-1. The optimum pH was aprox. 4 and the optimum

  3. Production of thermophilic and acidophilic endoglucanases by ...

    African Journals Online (AJOL)

    Production of thermophilic and acidophilic endoglucanases by mutant Trichoderma atroviride 102C1 using agro-industrial by-products. ... The effect of the carbon (sugarcane bagasse: SCB) and nitrogen (corn steep liquor: CSL) sources on ...

  4. Rapid startup of thermophilic anaerobic digester to remove tetracycline and sulfonamides resistance genes from sewage sludge.

    Science.gov (United States)

    Xu, Rui; Yang, Zhao-Hui; Wang, Qing-Peng; Bai, Yang; Liu, Jian-Bo; Zheng, Yue; Zhang, Yan-Ru; Xiong, Wei-Ping; Ahmad, Kito; Fan, Chang-Zheng

    2018-01-15

    Spread of antibiotic resistance genes (ARGs) originating from sewage sludge is highlighted as an eminent health threat. This study established a thermophilic anaerobic digester using one-step startup strategy to quickly remove tetracycline and sulfonamides resistance genes from sewage sludge. At least 20days were saved in the startup period from mesophilic to thermophilic condition. Based on the results of 16S rDNA amplicons sequencing and predicted metagenomic method, the successful startup largely relied on the fast colonization of core thermophilic microbial population (e.g. Firmicutes, Proteobacteria, Actinobacteria). Microbial metabolic gene pathways for substrate degradation and methane production was also increased by one-step mode. In addition, real-time quantitative PCR approach revealed that most targeted tetracycline and sulfonamides resistance genes ARGs (sulI, tetA, tetO, tetX) were substantially removed during thermophilic digestion (removal efficiency>80%). Network analysis showed that the elimination of ARGs was attributed to the decline of their horizontal (intI1 item) and vertical (potential hosts) transfer-related elements under high-temperature. This research demonstrated that rapid startup thermophilic anaerobic digestion of wastewater solids would be a suitable technology for reducing quantities of various ARGs. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. 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.

  6. Industrial relevance of thermophilic Archaea.

    Science.gov (United States)

    Egorova, Ksenia; Antranikian, Garabed

    2005-12-01

    The dramatic increase of newly isolated extremophilic microorganisms, analysis of their genomes and investigations of their enzymes by academic and industrial laboratories demonstrate the great potential of extremophiles in industrial (white) biotechnology. Enzymes derived from extremophiles (extremozymes) are superior to the traditional catalysts because they can perform industrial processes even under harsh conditions, under which conventional proteins are completely denatured. In particular, enzymes from thermophilic and hyperthermophilic Archaea have industrial relevance. Despite intensive investigations, our knowledge of the structure-function relationships of their enzymes is still limited. Information concerning the molecular properties of their enzymes and genes has to be obtained to be able to understand the mechanisms that are responsible for catalytic activity and stability at the boiling point of water.

  7. Production of D-xylanases by thermophilic fungi using different methods of culture

    Energy Technology Data Exchange (ETDEWEB)

    Grajek, W

    1986-01-01

    Seven thermophilic strains of fungi were examined for their ability to produce D-xylanase in liquid and solid-state fermentations. It was confirmed that the best producers of xylanase, among microorganisms used, were H. lanuginosa and S. thermophile in liquid fermentation, and T. aurantiacus and H. lanuginosa in solid-state fermentations. The higher productivity of xylanase, namely 18,72 IU/ml, was obtained in liquid culture of H. lanuginosa. The pH and temperature optima of enzymes from liquid and solid-state cultures of fungi used were also presented.

  8. Bacillus sp. JR3 esterase LipJ: A new mesophilic enzyme showing traces of a thermophilic past.

    Directory of Open Access Journals (Sweden)

    Judit Ribera

    Full Text Available A search for extremophile enzymes from ancient volcanic soils in El Hierro Island (Canary Islands, Spain allowed isolation of a microbial sporulated strain collection from which several enzymatic activities were tested. Isolates were obtained after sample cultivation under several conditions of nutrient contents and temperature. Among the bacterial isolates, supernatants from the strain designated JR3 displayed high esterase activity at temperatures ranging from 30 to 100°C, suggesting the presence of at least a hyper-thermophilic extracellular lipase. Sequence alignment of known thermophilic lipases allowed design of degenerated consensus primers for amplification and cloning of the corresponding lipase, named LipJ. However, the cloned enzyme displayed maximum activity at 30°C and pH 7, showing a different profile from that observed in supernatants of the parental strain. Sequence analysis of the cloned protein showed a pentapeptide motif -GHSMG- distinct from that of thermophilic lipases, and much closer to that of esterases. Nevertheless, the 3D structural model of LipJ displayed the same folding as that of thermophilic lipases, suggesting a common evolutionary origin. A phylogenetic study confirmed this possibility, positioning LipJ as a new member of the thermophilic family of bacterial lipases I.5. However, LipJ clusters in a clade close but separated from that of Geobacillus sp. thermophilic lipases. Comprehensive analysis of the cloned enzyme suggests a common origin of LipJ and other bacterial thermophilic lipases, and highlights the most probable divergent evolutionary pathway followed by LipJ, which during the harsh past times would have probably been a thermophilic enzyme, having lost these properties when the environment changed to more benign conditions.

  9. Bacillus sp. JR3 esterase LipJ: A new mesophilic enzyme showing traces of a thermophilic past.

    Science.gov (United States)

    Ribera, Judit; Estupiñán, Mónica; Fuentes, Alba; Fillat, Amanda; Martínez, Josefina; Diaz, Pilar

    2017-01-01

    A search for extremophile enzymes from ancient volcanic soils in El Hierro Island (Canary Islands, Spain) allowed isolation of a microbial sporulated strain collection from which several enzymatic activities were tested. Isolates were obtained after sample cultivation under several conditions of nutrient contents and temperature. Among the bacterial isolates, supernatants from the strain designated JR3 displayed high esterase activity at temperatures ranging from 30 to 100°C, suggesting the presence of at least a hyper-thermophilic extracellular lipase. Sequence alignment of known thermophilic lipases allowed design of degenerated consensus primers for amplification and cloning of the corresponding lipase, named LipJ. However, the cloned enzyme displayed maximum activity at 30°C and pH 7, showing a different profile from that observed in supernatants of the parental strain. Sequence analysis of the cloned protein showed a pentapeptide motif -GHSMG- distinct from that of thermophilic lipases, and much closer to that of esterases. Nevertheless, the 3D structural model of LipJ displayed the same folding as that of thermophilic lipases, suggesting a common evolutionary origin. A phylogenetic study confirmed this possibility, positioning LipJ as a new member of the thermophilic family of bacterial lipases I.5. However, LipJ clusters in a clade close but separated from that of Geobacillus sp. thermophilic lipases. Comprehensive analysis of the cloned enzyme suggests a common origin of LipJ and other bacterial thermophilic lipases, and highlights the most probable divergent evolutionary pathway followed by LipJ, which during the harsh past times would have probably been a thermophilic enzyme, having lost these properties when the environment changed to more benign conditions.

  10. Enzyme dynamics and hydrogen tunnelling in a thermophilic alcohol dehydrogenase

    Science.gov (United States)

    Kohen, Amnon; Cannio, Raffaele; Bartolucci, Simonetta; Klinman, Judith P.; Klinman, Judith P.

    1999-06-01

    Biological catalysts (enzymes) speed up reactions by many orders of magnitude using fundamental physical processes to increase chemical reactivity. Hydrogen tunnelling has increasingly been found to contribute to enzyme reactions at room temperature. Tunnelling is the phenomenon by which a particle transfers through a reaction barrier as a result of its wave-like property. In reactions involving small molecules, the relative importance of tunnelling increases as the temperature is reduced. We have now investigated whether hydrogen tunnelling occurs at elevated temperatures in a biological system that functions physiologically under such conditions. Using a thermophilic alcohol dehydrogenase (ADH), we find that hydrogen tunnelling makes a significant contribution at 65°C this is analogous to previous findings with mesophilic ADH at 25°C ( ref. 5). Contrary to predictions for tunnelling through a rigid barrier, the tunnelling with the thermophilic ADH decreases at and below room temperature. These findings provide experimental evidence for a role of thermally excited enzyme fluctuations in modulating enzyme-catalysed bond cleavage.

  11. State of the art review of biofuels production from lignocellulose by thermophilic bacteria.

    Science.gov (United States)

    Jiang, Yujia; Xin, Fengxue; Lu, Jiasheng; Dong, Weiliang; Zhang, Wenming; Zhang, Min; Wu, Hao; Ma, Jiangfeng; Jiang, Min

    2017-12-01

    Biofuels, including ethanol and butanol, are mainly produced by mesophilic solventogenic yeasts and Clostridium species. However, these microorganisms cannot directly utilize lignocellulosic materials, which are abundant, renewable and non-compete with human demand. More recently, thermophilic bacteria show great potential for biofuels production, which could efficiently degrade lignocellulose through the cost effective consolidated bioprocessing. Especially, it could avoid contamination in the whole process owing to its relatively high fermentation temperature. However, wild types thermophiles generally produce low levels of biofuels, hindering their large scale production. This review comprehensively summarizes the state of the art development of biofuels production by reported thermophilic microorganisms, and also concludes strategies to improve biofuels production including the metabolic pathways construction, co-culturing systems and biofuels tolerance. In addition, strategies to further improve butanol production are proposed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Comparing the Bio-Hydrogen Production Potential of Pretreated Rice Straw Co-Digested with Seeded Sludge Using an Anaerobic Bioreactor under Mesophilic Thermophilic Conditions

    Directory of Open Access Journals (Sweden)

    Asma Sattar

    2016-03-01

    Full Text Available Three common pretreatments (mechanical, steam explosion and chemical used to enhance the biodegradability of rice straw were compared on the basis of bio-hydrogen production potential while co-digesting rice straw with sludge under mesophilic (37 °C and thermophilic (55 °C temperatures. The results showed that the solid state NaOH pretreatment returned the highest experimental reduction of LCH (lignin, cellulose and hemi-cellulose content and bio-hydrogen production from rice straw. The increase in incubation temperature from 37 °C to 55 °C increased the bio-hydrogen yield, and the highest experimental yield of 60.6 mL/g VSremoved was obtained under chemical pretreatment at 55 °C. The time required for maximum bio-hydrogen production was found on the basis of kinetic parameters as 36 h–47 h of incubation, which can be used as a hydraulic retention time for continuous bio-hydrogen production from rice straw. The optimum pH range of bio-hydrogen production was observed to be 6.7 ± 0.1–5.8 ± 0.1 and 7.1 ± 0.1–5.8 ± 0.1 under mesophilic and thermophilic conditions, respectively. The increase in temperature was found useful for controlling the volatile fatty acids (VFA under mechanical and steam explosion pretreatments. The comparison of pretreatment methods under the same set of experimental conditions in the present study provided a baseline for future research in order to select an appropriate pretreatment method.

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

    DEFF Research Database (Denmark)

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

    1994-01-01

    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...

  14. Enrichment of Thermophilic Syntrophic Anaerobic Glutamate-Degrading Consortia using a Dialysis Membrane Reactor

    NARCIS (Netherlands)

    Plugge, C.M.; Stams, A.J.M.

    2002-01-01

    A dialysis cultivation system was used to enrich slow-growing moderately thermophilic anaerobic bacteria at high cell densities. Bicarbonate buffered mineral salts medium with 5 mM glutamate as the sole carbon and energy source was used and the incubation temperature was 55 degrees C. The reactor

  15. Energetic and hydrogen limitations of thermophilic and hyperthermophilic methanogens

    Science.gov (United States)

    Stewart, L. C.; Holden, J. F.

    2013-12-01

    Deep-sea hydrothermal vents are a unique ecosystem, based ultimately not on photosynthesis but chemosynthetic primary production. This makes them an excellent analog environment for the early Earth, and for potential extraterrestrial habitable environments, such as those on Mars and Europa. The habitability of given vent systems for chemoautotrophic prokaryotes can be modeled energetically by estimating the available Gibbs energy for specific modes of chemoautotrophy, using geochemical data and mixing models for hydrothermal fluids and seawater (McCollom and Shock, 1997). However, modeling to date has largely not taken into account variation in organisms' energy demands in these environments. Controls on maintenance energies are widely assumed to be temperature-dependent, rising with increasing temperature optima (Tijhuis et al., 1993), and species-independent. The impacts of other environmental stressors and particular energy-gathering strategies on maintenance energies have not been investigated. We have undertaken culture-based studies of growth and maintenance energies in thermophilic and hyperthermophilic methanogenic (hydrogenotrophic) archaea from deep-sea hydrothermal vents to investigate potential controls on energy demands in hydrothermal vent microbes, and to quantify their growth and maintenance energies for future bioenergetic modeling. We have investigated trends in their growth energies over their full temperature range and a range of nitrogen concentrations, and in their maintenance energies at different hydrogen concentrations. Growth energies in these organisms appear to rise with temperature, but do not vary between hyperthermophilic and thermophilic methanogens. Nitrogen availability at tested levels (40μM - 9.4 mM) does not appear to affect growth energies in all but one tested organism. In continuous chemostat culture, specific methane production varied with hydrogen availability but was similar between a thermophilic and a hyperthermophilic

  16. Changes of resistome, mobilome and potential hosts of antibiotic resistance genes during the transformation of anaerobic digestion from mesophilic to thermophilic.

    Science.gov (United States)

    Tian, Zhe; Zhang, Yu; Yu, Bo; Yang, Min

    2016-07-01

    This study aimed to reveal how antibiotic resistance genes (ARGs) and their horizontal and vertical transfer-related items (mobilome and bacterial hosts) respond to the transformation of anaerobic digestion (AD) from mesophilic to thermophilic using one-step temperature increase. The resistomes and mobilomes of mesophilic and thermophilic sludge were investigated using metagenome sequencing, and the changes in 24 representative ARGs belonging to three categories, class 1 integron and bacterial genera during the transition period were further followed using quantitative PCR and 454-pyrosequencing. After the temperature increase, resistome abundance in the digested sludge decreased from 125.97 ppm (day 0, mesophilic) to 50.65 ppm (day 57, thermophilic) with the reduction of most ARG types except for the aminoglycoside resistance genes. Thermophilic sludge also had a smaller mobilome, including plasmids, insertion sequences and integrons, than that of mesophilic sludge, suggesting the lower horizontal transfer potential of ARGs under thermophilic conditions. On the other hand, the total abundance of 18 bacterial genera, which were suggested as the possible hosts for 13 ARGs through network analysis, decreased from 23.27% in mesophilic sludge to 11.92% in thermophilic sludge, indicating fewer hosts for the vertical expansion of ARGs after the increase in temperature. These results indicate that the better reduction of resistome abundance by thermophilic AD might be associated with the decrease of both the horizontal and vertical transferability of ARGs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Single-step ethanol production from lignocellulose using novel extremely thermophilic bacteria.

    Science.gov (United States)

    Svetlitchnyi, Vitali A; Kensch, Oliver; Falkenhan, Doris A; Korseska, Svenja G; Lippert, Nadine; Prinz, Melanie; Sassi, Jamaleddine; Schickor, Anke; Curvers, Simon

    2013-02-28

    Consolidated bioprocessing (CBP) of lignocellulosic biomass to ethanol using thermophilic bacteria provides a promising solution for efficient lignocellulose conversion without the need for additional cellulolytic enzymes. Most studies on the thermophilic CBP concentrate on co-cultivation of the thermophilic cellulolytic bacterium Clostridium thermocellum with non-cellulolytic thermophilic anaerobes at temperatures of 55°C-60°C. We have specifically screened for cellulolytic bacteria growing at temperatures >70°C to enable direct conversion of lignocellulosic materials into ethanol. Seven new strains of extremely thermophilic anaerobic cellulolytic bacteria of the genus Caldicellulosiruptor and eight new strains of extremely thermophilic xylanolytic/saccharolytic bacteria of the genus Thermoanaerobacter isolated from environmental samples exhibited fast growth at 72°C, extensive lignocellulose degradation and high yield ethanol production on cellulose and pretreated lignocellulosic biomass. Monocultures of Caldicellulosiruptor strains degraded up to 89-97% of the cellulose and hemicellulose polymers in pretreated biomass and produced up to 72 mM ethanol on cellulose without addition of exogenous enzymes. In dual co-cultures of Caldicellulosiruptor strains with Thermoanaerobacter strains the ethanol concentrations rose 2- to 8.2-fold compared to cellulolytic monocultures. A co-culture of Caldicellulosiruptor DIB 087C and Thermoanaerobacter DIB 097X was particularly effective in the conversion of cellulose to ethanol, ethanol comprising 34.8 mol% of the total organic products. In contrast, a co-culture of Caldicellulosiruptor saccharolyticus DSM 8903 and Thermoanaerobacter mathranii subsp. mathranii DSM 11426 produced only low amounts of ethanol. The newly discovered Caldicellulosiruptor sp. strain DIB 004C was capable of producing unexpectedly large amounts of ethanol from lignocellulose in fermentors. The established co-cultures of new Caldicellulosiruptor

  18. Influence of temperature on the fixation and penetration of silver during the chalcopyrite leaching using moderate thermophilic microorganisms; Influencia de la temperatura en la fijacion y penetracion de la plata durante la lixiviacion de calcopirita con microorganismos termofilos moderados

    Energy Technology Data Exchange (ETDEWEB)

    Cancho, L.; Blazquez, M. L.; Munoz, J. A.; Gonzalez, F.; Ballester, A.

    2004-07-01

    Bio leaching of chalcopyrite using mesophilic microorganisms considerable improves in the presence of silver. However, the studies carried out with moderate thermophilic microorganisms do not show a significant improvement with regard to the use of mesophilic bacteria. The main objective of the present work has been to study the silver fixation on chalcopyrite ar 35 and 45 degree centigree and its influence on the microbiological attack. Different observations using SEM, EDS microanalysis and concentration profiles using electron microprobe have been carried out. The study of the different samples showed that silver fixation was more favourable at 35 degree centigree than at 45 degree centigree. In addition, bacterial action improved silver penetration through attack cracks. (Author)

  19. 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

  20. Highly Stable l-Lysine 6-Dehydrogenase from the Thermophile Geobacillus stearothermophilus Isolated from a Japanese Hot Spring: Characterization, Gene Cloning and Sequencing, and Expression

    Science.gov (United States)

    Heydari, Mojgan; Ohshima, Toshihisa; Nunoura-Kominato, Naoki; Sakuraba, Haruhiko

    2004-01-01

    l-Lysine dehydrogenase, which catalyzes the oxidative deamination of l-lysine in the presence of NAD, was found in the thermophilic bacterium Geobacillus stearothermophilus UTB 1103 and then purified about 3,040-fold from a crude extract of the organism by using four successive column chromatography steps. This is the first report showing the presence of a thermophilic NAD-dependent lysine dehydrogenase. The product of the enzyme catalytic activity was determined to be Δ1-piperideine-6-carboxylate, indicating that the enzyme is l-lysine 6-dehydrogenase (LysDH) (EC 1.4.1.18). The molecular mass of the purified protein was about 260 kDa, and the molecule was determined to be a homohexamer with subunit molecular mass of about 43 kDa. The optimum pH and temperature for the catalytic activity of the enzyme were about 10.1 and 70°C, respectively. No activity was lost at temperatures up to 65°C in the presence of 5 mM l-lysine. The enzyme was relatively selective for l-lysine as the electron donor, and either NAD or NADP could serve as the electron acceptor (NADP exhibited about 22% of the activity of NAD). The Km values for l-lysine, NAD, and NADP at 50°C and pH 10.0 were 0.73, 0.088, and 0.48 mM, respectively. When the gene encoding this LysDH was cloned and overexpressed in Escherichia coli, a crude extract of the recombinant cells had about 800-fold-higher enzyme activity than the extract of G. stearothermophilus. The nucleotide sequence of the LysDH gene encoded a peptide containing 385 amino acids with a calculated molecular mass of 42,239 Da. PMID:14766574

  1. Comparative study of two purified inulinases from thermophile Thielavia Terrestris NRRL 8126 and mesophile Aspergillus Foetidus NRRL 337 grown on Cichorium Intybus l

    Directory of Open Access Journals (Sweden)

    Eman Mohamed Fawzi

    2011-06-01

    Full Text Available Thirty fungal species grown on Cichorium intybus L. root extract as a sole carbon source, were screened for the production of exo-inulinase activities. The thermophile Thielavia terrestris NRRL 8126 and mesophile Aspergillus foetidus NRRL 337 gave the highest production levels of inulinases I & II at 50 and 24 ºC respectively. Yeast extract and peptone were the best nitrogen sources for highest production of inulinases I & II at five and seven days of incubation respectively. The two inulinases I & II were purified to homogeneity by gel-filtration and ion-exchange chromatography with 66.0 and 42.0 fold of purification respectively. The optimum temperatures of purified inulinases I & II were 75 and 50 ºC respectively. Inulinase I was more thermostable than the other one. The optimum pH for activity was found to be 4.5 and 5.5 for inulinases I & II respectively. A comparatively lower Michaelis-Menten constant (2.15 mg/ml and higher maximum initial velocity (115 µmol/min/mg of protein for inulinase I on inulin demonstrated the exoinulinase's greater affinity for inulin substrate. These findings are significant for its potential industrial application. The molecular mass of the inulinases I & II were estimated to be 72 & 78 kDa respectively by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

  2. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Experimental assessment of factors influencing dewatering properties of thermophilically digested biosolids

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jianpeng; Mavinic, Donald S.; Kelly, Harlan G.; Ramey, William D.

    2003-07-01

    Beneficial land application of processed wastewater sludges (biosolids) is a cost-effective, and environmentally sustainable option for the final disposal of sludges, because nutrients and organic matters in the sludge are recovered and reused as a resource. Thermophilic sludge digestion produces Class A biosolids, which can be reused without restrictions. Recent experience from full-scale thermophilic sludge digestion facilities in North America revealed that, dewatering thermophilically digested biosolids required more polymers to condition than mesophilically digested biosolids. This paper reports a laboratory study that investigated factors having significant impacts on dewatering properties of digested biosolids, and assessed the relationship among digestion, dewatering properties, and characteristics of thermophilically digested biosolids. The experimental work used batch-operated, bench-scale aerobic sludge digesters. Dewaterability was measured as Capillary Suction Time (CST). The study found that feed sludge composition significantly affected dewaterability of digested sludge. Higher percentage of the secondary sludge in the feed sludge corresponded to more significant deterioration in dewaterability. The effect of thermophilic digestion temperatures on dewaterabilty was rapid, occurred within 3-hour of digestion, indicting a heat shock effect, rather than a microbiological effect. When a high shear was applied to the sludge in digesters, it resulted In a significant deterioration in dewaterability in the digested sludge. It appears there was a strong correlation between dewaterability and extracellular biopolymers. Enzymes (protease) treatment confirmed that role of extracellular proteins in affecting the dewatering properties of thermophilic biosolids, also revealed the complex nature of biopolymers' effect on dewaterability. Such effects might be due to protein-polysaccharides interactions, hydrogen bonding, or hydrophilic and hydrophobic

  4. Mesophilic and thermophilic biotreatment of BTEX-polluted air in reactors.

    Science.gov (United States)

    Mohammad, Balsam T; Veiga, María C; Kennes, Christian

    2007-08-15

    This study compares the removal of a mixture of benzene, toluene, ethylbenzene, and all three xylene isomers (BTEX) in mesophilic and thermophilic (50 degrees C) bioreactors. In the mesophilic reactor fungi became dominant after long-term operation, while bacteria dominated in the thermophilic unit. Microbial acclimation was achieved by exposing the biofilters to initial BTEX loads of 2-15 g m(-3) h(-1), at an empty bed residence time of 96 s. After adaptation, the elimination capacities ranged from 3 to 188 g m(-3) h(-1), depending on the inlet load, for the mesophilic biofilter with removal efficiencies reaching 96%. On the other hand, in the thermophilic reactor the average removal efficiency was 83% with a maximum elimination capacity of 218 g m(-3) h(-1). There was a clear positive relationship between temperature gradients as well as CO(2) production and elimination capacities across the biofilters. The gas phase was sampled at different depths along the reactors observing that the percentage pollutant removal in each section was strongly dependant on the load applied. The fate of individual alkylbenzene compounds was checked, showing the unusually high biodegradation rate of benzene at high loads under thermophilic conditions (100%) compared to its very low removal in the mesophilic reactor at such load (<10%). Such difference was less pronounced for the other pollutants. After 210 days of operation, the dry biomass content for the mesophilic and thermophilic reactors were 0.300 and 0.114 g g(-1) (support), respectively, reaching higher removals under thermophilic conditions with a lower biomass accumulation, that is, lower pressure drop. (c) 2007 Wiley Periodicals, Inc.

  5. Optimum Design of Plasma Focus

    International Nuclear Information System (INIS)

    Ramos, Ruben; Gonzalez, Jose; Clausse, Alejandro

    2000-01-01

    The optimum design of Plasma Focus devices is presented based in a lumped parameter model of the MHD equations.Maps in the design parameters space are obtained, which determine the length and deuterium pressure required to produce a given neutron yield.Sensitivity analyses of the main effective numbers (sweeping efficiencies) was performed, and lately the optimum values were determined in order to set a basis for the conceptual design

  6. Caldicellulosiruptor obsidiansis sp. nov., an anaerobic, extremely thermophilic, cellulolytic bacterium isolated from Obsidian Pool, Yellowstone National Park.

    Science.gov (United States)

    Hamilton-Brehm, Scott D; Mosher, Jennifer J; Vishnivetskaya, Tatiana; Podar, Mircea; Carroll, Sue; Allman, Steve; Phelps, Tommy J; Keller, Martin; Elkins, James G

    2010-02-01

    A novel, obligately anaerobic, extremely thermophilic, cellulolytic bacterium, designated OB47(T), was isolated from Obsidian Pool, Yellowstone National Park, WY. The isolate was a nonmotile, non-spore-forming, Gram-positive rod approximately 2 microm long by 0.2 microm wide and grew at temperatures between 55 and 85 degrees C, with the optimum at 78 degrees C. The pH range for growth was 6.0 to 8.0, with values of near 7.0 being optimal. Growth on cellobiose produced the fastest specific growth rate at 0.75 h(-1). The organism also displayed fermentative growth on glucose, maltose, arabinose, fructose, starch, lactose, mannose, sucrose, galactose, xylose, arabinogalactan, Avicel, xylan, filter paper, processed cardboard, pectin, dilute acid-pretreated switchgrass, and Populus. OB47(T) was unable to grow on mannitol, fucose, lignin, Gelrite, acetate, glycerol, ribose, sorbitol, carboxymethylcellulose, and casein. Yeast extract stimulated growth, and thiosulfate, sulfate, nitrate, and sulfur were not reduced. Fermentation end products were mainly acetate, H2, and CO2, although lactate and ethanol were produced in 5-liter batch fermentations. The G+C content of the DNA was 35 mol%, and sequence analysis of the small subunit rRNA gene placed OB47(T) within the genus Caldicellulosiruptor. Based on its phylogenetic and phenotypic properties, the isolate is proposed to be designated Caldicellulosiruptor obsidiansis sp. nov. and OB47 is the type strain (ATCC BAA-2073).

  7. Caldicellulosiruptor obsidiansis sp. nov., an Anaerobic, Extremely Thermophilic, Cellulolytic Bacterium Isolated from Obsidian Pool, Yellowstone National Park▿

    Science.gov (United States)

    Hamilton-Brehm, Scott D.; Mosher, Jennifer J.; Vishnivetskaya, Tatiana; Podar, Mircea; Carroll, Sue; Allman, Steve; Phelps, Tommy J.; Keller, Martin; Elkins, James G.

    2010-01-01

    A novel, obligately anaerobic, extremely thermophilic, cellulolytic bacterium, designated OB47T, was isolated from Obsidian Pool, Yellowstone National Park, WY. The isolate was a nonmotile, non-spore-forming, Gram-positive rod approximately 2 μm long by 0.2 μm wide and grew at temperatures between 55 and 85°C, with the optimum at 78°C. The pH range for growth was 6.0 to 8.0, with values of near 7.0 being optimal. Growth on cellobiose produced the fastest specific growth rate at 0.75 h−1. The organism also displayed fermentative growth on glucose, maltose, arabinose, fructose, starch, lactose, mannose, sucrose, galactose, xylose, arabinogalactan, Avicel, xylan, filter paper, processed cardboard, pectin, dilute acid-pretreated switchgrass, and Populus. OB47T was unable to grow on mannitol, fucose, lignin, Gelrite, acetate, glycerol, ribose, sorbitol, carboxymethylcellulose, and casein. Yeast extract stimulated growth, and thiosulfate, sulfate, nitrate, and sulfur were not reduced. Fermentation end products were mainly acetate, H2, and CO2, although lactate and ethanol were produced in 5-liter batch fermentations. The G+C content of the DNA was 35 mol%, and sequence analysis of the small subunit rRNA gene placed OB47T within the genus Caldicellulosiruptor. Based on its phylogenetic and phenotypic properties, the isolate is proposed to be designated Caldicellulosiruptor obsidiansis sp. nov. and OB47 is the type strain (ATCC BAA-2073). PMID:20023107

  8. Mesophilic and thermophilic anaerobic biodegradability of water hyacinth pre-treated at 80 degrees C.

    Science.gov (United States)

    Ferrer, Ivet; Palatsi, Jordi; Campos, Elena; Flotats, Xavier

    2010-10-01

    Water hyacinth (Eichornia crassipes) is a fast growing aquatic plant which causes environmental problems in continental water bodies. Harvesting and handling this plant becomes an issue, and focus has been put on the research of treatment alternatives. Amongst others, energy production through biomethanation has been proposed. The aim of this study was to assess the anaerobic biodegradability of water hyacinth under mesophilic and thermophilic conditions. The effect of a thermal sludge pre-treatment at 80 degrees C was also evaluated. To this end, anaerobic biodegradability tests were carried out at 35 degrees C and 55 degrees C, with raw and pre-treated water hyacinth. According to the results, the thermal pre-treatment enhanced the solubilisation of water hyacinth (i.e. increase in the soluble to total chemical oxygen demand (COD)) from 4% to 12% after 30 min. However, no significant effect was observed on the methane yields (150-190 L CH(4)/kg volatile solids). Initial methane production rates for thermophilic treatments were two fold those of mesophilic ones (6-6.5L vs. 3-3.5 L CH(4)/kg COD x day). Thus, higher methane production rates might be expected from thermophilic reactors working at short retention times. The study of longer low temperature pre-treatments or pre-treatments at elevated temperatures coupled to thermophilic reactors should be considered in the future. (c) 2009 Elsevier Ltd. All rights reserved.

  9. Mesophilic and thermophilic anaerobic biodegradability of water hyacinth pre-treated at 80 oC

    International Nuclear Information System (INIS)

    Ferrer, Ivet; Palatsi, Jordi; Campos, Elena; Flotats, Xavier

    2010-01-01

    Water hyacinth (Eichornia crassipes) is a fast growing aquatic plant which causes environmental problems in continental water bodies. Harvesting and handling this plant becomes an issue, and focus has been put on the research of treatment alternatives. Amongst others, energy production through biomethanation has been proposed. The aim of this study was to assess the anaerobic biodegradability of water hyacinth under mesophilic and thermophilic conditions. The effect of a thermal sludge pre-treatment at 80 o C was also evaluated. To this end, anaerobic biodegradability tests were carried out at 35 o C and 55 o C, with raw and pre-treated water hyacinth. According to the results, the thermal pre-treatment enhanced the solubilisation of water hyacinth (i.e. increase in the soluble to total chemical oxygen demand (COD)) from 4% to 12% after 30 min. However, no significant effect was observed on the methane yields (150-190 L CH 4 /kg volatile solids). Initial methane production rates for thermophilic treatments were two fold those of mesophilic ones (6-6.5 L vs. 3-3.5 L CH 4 /kg COD.day). Thus, higher methane production rates might be expected from thermophilic reactors working at short retention times. The study of longer low temperature pre-treatments or pre-treatments at elevated temperatures coupled to thermophilic reactors should be considered in the future.

  10. Inactivation of Clostridium difficile in sewage sludge by anaerobic thermophilic digestion.

    Science.gov (United States)

    Xu, Changyun; Salsali, Hamidreza; Weese, Scott; Warriner, Keith

    2016-01-01

    There has been an increase in community-associated Clostridium difficile infections with biosolids derived from wastewater treatment being identified as one potential source. The current study evaluated the efficacy of thermophilic digestion in decreasing levels of C. difficile ribotype 078 associated with sewage sludge. Five isolates of C. difficile 078 were introduced (final density of 5 log CFU/g) into digested sludge and subjected to anaerobic digestion at mesophilic (36 or 42 °C) or thermophilic (55 °C) temperatures for up to 60 days. It was found that mesophilic digestion at 36 °C did not result in a significant reduction in C. difficile spore levels. In contrast, thermophilic sludge digestion reduced endospore levels at a rate of 0.19-2.68 log CFU/day, depending on the strain tested. The mechanism of lethality was indirect - by stimulating germination then inactivating the resultant vegetative cells. Acidification of sludge by adding acetic acid (6 g/L) inhibited the germination of spores regardless of the sludge digestion temperature. In conclusion, thermophilic digestion can be applied to reduce C. difficile in biosolids, thereby reducing the environmental burden of the enteric pathogen.

  11. Characterization of thermophilic fungal community associated with pile fermentation of Pu-erh tea.

    Science.gov (United States)

    Zhang, Wei; Yang, Ruijuan; Fang, Wenjun; Yan, Liang; Lu, Jun; Sheng, Jun; Lv, Jie

    2016-06-16

    This study aimed to characterize the thermophilic fungi in pile-fermentation process of Pu-erh tea. Physicochemical analyses showed that the high temperature and low pH provided optimal conditions for propagation of fungi. A number of fungi, including Blastobotrys adeninivorans, Thermomyces lanuginosus, Rasamsonia emersonii, Aspergillus fumigatus, Rhizomucor pusillus, Rasamsonia byssochlamydoides, Rasamsonia cylindrospora, Aspergillus tubingensis, Aspergillus niger, Candida tropicalis and Fusarium graminearum were isolated as thermophilic fungi under combination of high temperature and acid culture conditions from Pu-erh tea pile-fermentation. The fungal communities were analyzed by PCR-DGGE. Results revealed that those fungi are closely related to Debaryomyces hansenii, Cladosporium cladosporioides, A. tubingensis, R. emersonii, R. pusillus, A. fumigatus and A. niger, and the last four presented as dominant species in the pile process. These four preponderant thermophilic fungi reached the order of magnitude of 10(7), 10(7), 10(7) and 10(6)copies/g dry tea, respectively, measured by real-time quantitative PCR (q-PCR). The results indicate that the thermophilic fungi play an important role in Pu-erh tea pile fermentation. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Bioprospecting thermophiles for cellulase production: a review.

    Science.gov (United States)

    Acharya, Somen; Chaudhary, Anita

    2012-07-01

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

  13. 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.

  14. Diversity and ubiquity of thermophilic methanogenic archaea in temperate anoxic soils.

    Science.gov (United States)

    Wu, Xiao-Lei; Friedrich, Michael W; Conrad, Ralf

    2006-03-01

    Temperate rice field soil from Vercelli (Italy) contains moderately thermophilic methanogens of the yet uncultivated rice cluster I (RC-I), which become prevalent upon incubation at temperatures of 45-50 degrees C. We studied whether such thermophilic methanogens were ubiquitously present in anoxic soils. Incubation of different rice field soils (from Italy, China and the Philippines) and flooded riparian soils (from the Netherlands) at 45 degrees C resulted in vigorous CH(4) production after a lag phase of about 10 days. The archaeal community structure in the soils was analysed by terminal restriction fragment length polymorphism (T-RFLP) targeting the SSU rRNA genes retrieved from the soil, and by cloning and sequencing. Clones of RC-I methanogens mostly exhibited T-RF of 393 bp, but also terminal restriction fragment (T-RF) of 158 and 258 bp length, indicating a larger diversity than previously assumed. No RC-I methanogens were initially found in flooded riparian soils. However, these archaea became abundant upon incubation of the soil at 45 degrees C. Thermophilic RC-I methanogens were also found in the rice field soils from Pavia, Pila and Gapan. However, the archaeal communities in these soils also contained other methanogenic archaea at high temperature. Rice field soil from Buggalon, on the other hand, only contained thermophilic Methanomicrobiales rather than RC-I methanogens, and rice field soil from Jurong mostly Methanomicrobiales and only a few RC-I methanogens. The archaeal community of rice field soil from Zhenjiang almost exclusively consisted of Methanosarcinaceae when incubated at high temperature. Our results show that moderately thermophilic methanogens are common in temperate soils. However, RC-I methanogens are not always dominating or ubiquitous.

  15. Protein dynamics and stability: The distribution of atomic fluctuations in thermophilic and mesophilic dihydrofolate reductase derived using elastic incoherent neutron scattering

    International Nuclear Information System (INIS)

    Meinhold, Lars; Clement, David; Tehei, M.; Daniel, R.M.; Finney, J.L.; Smith, Jeremy C.

    2008-01-01

    The temperature dependence of the dynamics of mesophilic and thermophilic dihydrofolate reductase is examined using elastic incoherent neutron scattering. It is demonstrated that the distribution of atomic displacement amplitudes can be derived from the elastic scattering data by assuming a (Weibull) functional form that resembles distributions seen in molecular dynamics simulations. The thermophilic enzyme has a significantly broader distribution than its mesophilic counterpart. Furthermore, although the rate of increase with temperature of the atomic mean-square displacements extracted from the dynamic structure factor is found to be comparable for both enzymes, the amplitudes are found to be slightly larger for the thermophilic enzyme. Therefore, these results imply that the thermophilic enzyme is the more flexible of the two

  16. Effects of pH and hydraulic retention time on hydrogen production versus methanogenesis during anaerobic fermentation of organic household solid waste under extreme-thermophilic temperature (70ºC)

    DEFF Research Database (Denmark)

    Liu, Dawei; Zeng, Raymond Jianxiong; Angelidaki, Irini

    2008-01-01

    Two continuously stirred tank reactors were operated with household solid waste at 70°C, for hydrogen and methane production. The individual effect of hydraulic retention time (HRT as 1, 2, 3, 4, and 6 days) at pH 7 or pH (5, 5.5, 6, 6.5, 7) at 3-day HRT was investigated on the hydrogen production...... versus methanogenesis. It was found that at pH 7, the maximum hydrogen yield was 107 mL-H2/g VSadded (volatile solid added) but no stable hydrogen production was obtained as after some time methanogenesis was initiated at all tested HRTs. This demonstrated that sludge retention time alone was not enough...... for washing out the methanogens at pH 7 under extreme-thermophilic conditions. Oppositely, we showed that keeping the pH level at 5.5 was enough to inhibit methane and produce hydrogen stably at 3-day HRT. However, the maximum stable hydrogen yield was low at 21 mL-H2/g VSadded. Biotechnol. Bioeng. 2008...

  17. Thermal Comfort and Optimum Humidity Part 1

    Directory of Open Access Journals (Sweden)

    M. V. Jokl

    2002-01-01

    Full Text Available The hydrothermal microclimate is the main component in indoor comfort. The optimum hydrothermal level can be ensured by suitable changes in the sources of heat and water vapor within the building, changes in the environment (the interior of the building and in the people exposed to the conditions inside the building. A change in the heat source and the source of water vapor involves improving the heat - insulating properties and the air permeability of the peripheral walls and especially of the windows. The change in the environment will bring human bodies into balance with the environment. This can be expressed in terms of an optimum or at least an acceptable globe temperature, an adequate proportion of radiant heat within the total amount of heat from the environment (defined by the difference between air and wall temperature, uniform cooling of the human body by the environment, defined a by the acceptable temperature difference between head and ankles, b by acceptable temperature variations during a shift (location unchanged, or during movement from one location to another without a change of clothing. Finally, a moisture balance between man and the environment is necessary (defined by acceptable relative air humidity. A change for human beings means a change of clothes which, of course, is limited by social acceptance in summer and by inconvenient heaviness in winter. The principles of optimum heating and cooling, humidification and dehumidification are presented in this paper.Hydrothermal comfort in an environment depends on heat and humidity flows (heat and water vapors, occurring in a given space in a building interior and affecting the total state of the human organism.

  18. Thermal Comfort and Optimum Humidity Part 2

    Directory of Open Access Journals (Sweden)

    M. V. Jokl

    2002-01-01

    Full Text Available The hydrothermal microclimate is the main component in indoor comfort. The optimum hydrothermal level can be ensured by suitable changes in the sources of heat and water vapor within the building, changes in the environment (the interior of the building and in the people exposed to the conditions inside the building. A change in the heat source and the source of water vapor involves improving the heat - insulating properties and the air permeability of the peripheral walls and especially of the windows. The change in the environment will bring human bodies into balance with the environment. This can be expressed in terms of an optimum or at least an acceptable globe temperature, an adequate proportion of radiant heat within the total amount of heat from the environment (defined by the difference between air and wall temperature, uniform cooling of the human body by the environment, defined a by the acceptable temperature difference between head and ankles, b by acceptable temperature variations during a shift (location unchanged, or during movement from one location to another without a change of clothing. Finally, a moisture balance between man and the environment is necessary (defined by acceptable relative air humidity. A change for human beings means a change of clothes which, of course, is limited by social acceptance in summer and by inconvenient heaviness in winter. The principles of optimum heating and cooling, humidification and dehumidification are presented in this paper.Hydrothermal comfort in an environment depends on heat and humidity flows (heat and water vapors, occurring in a given space in a building interior and affecting the total state of the human organism.

  19. Optimum Safety Levels for Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Sørensen, John Dalsgaard

    2005-01-01

    Optimum design safety levels for rock and cube armoured rubble mound breakwaters without superstructure are investigated by numerical simulations on the basis of minimization of the total costs over the service life of the structure, taking into account typical uncertainties related to wave...... statistics and structure response. The study comprises the influence of interest rate, service lifetime, downtime costs and damage accumulation. Design limit states and safety classes for breakwaters are discussed. The results indicate that optimum safety levels are somewhat higher than the safety levels...

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

    Science.gov (United States)

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

    2016-12-01

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

  1. Molecular characterization of thermophilic Campylobacter species ...

    African Journals Online (AJOL)

    We identified two species of thermophilic Campylobacter in companion dogs in Jos. Majority of C. jejuni were isolated from mucoid faeces while mixed infections of the two species were more common among diarrhoeic dogs. Pet owners should observe strict hand hygiene especially after handling dogs or their faeces to ...

  2. Screening of complex thermophilic microbial community and ...

    African Journals Online (AJOL)

    Screening of complex thermophilic microbial community and application during municipal solid waste aerobic composting. ... African Journal of Biotechnology ... Complex microbial community HP83 and HC181 were applied during municipal solid waste aerobic composting that was carried out in a composting reactor under ...

  3. Optimum target thickness for polarimeters

    International Nuclear Information System (INIS)

    Sitnik, I.M.

    2003-01-01

    Polarimeters with thick targets are a tool to measure the proton polarization. But the question about the optimum target thickness is still the subject of discussion. An attempt to calculate the most common parameters concerning this problem, in a few GeV region, is made

  4. Temperature-driven adaptation of the bacterial community in peat measured by using thymidine and leucine incorporation.

    Science.gov (United States)

    Ranneklev, S B; Bååth, E

    2001-03-01

    The temperature-driven adaptation of the bacterial community in peat was studied, by altering temperature to simulate self-heating and a subsequent return to mesophilic conditions. The technique used consisted of extracting the bacterial community from peat using homogenization-centrifugation and measuring the rates of thymidine (TdR) or leucine (Leu) incorporation by the extracted bacterial community at different temperatures. Increasing the peat incubation temperature from 25 degrees C to 35, 45, or 55 degrees C resulted in a selection of bacterial communities whose optimum temperatures for activity correlated to the peat incubation temperatures. Although TdR and Leu incorporations were significantly correlated, the Leu/TdR incorporation ratios were affected by temperature. Higher Leu/TdR incorporation ratios were found at higher temperatures of incubation of the extracted bacterial community. Higher Leu/TdR incorporation ratios were also found for bacteria in peat samples incubated at higher temperatures. The reappearance of the mesophilic community and disappearance of the thermophilic community when the incubation temperature of the peat was shifted down were monitored by measuring TdR incorporation at 55 degrees C (thermophilic activity) and 25 degrees C (mesophilic activity). Shifting the peat incubation temperature from 55 to 25 degrees C resulted in a recovery of the mesophilic activity, with a subsequent disappearance of the thermophilic activity. The availability of substrate for bacterial growth varied over time and among different peat samples. To avoid confounding effects of substrate availability, a temperature adaptation index was calculated. This index consisted of the log(10) ratio of TdR incorporation at 55 and 25 degrees C. The temperature index decreased linearly with time, indicating that no thermophilic activity would be detected by the TdR technique 1 month after the temperature downshift. There were no differences between the slopes of the

  5. Response of chironomid species (Diptera, Chironomidae to water temperature: effects on species distribution in specific habitats

    Directory of Open Access Journals (Sweden)

    L. Marziali

    2013-09-01

    Full Text Available The response of 443 chironomid species to water temperature was analyzed, with the aim of defining their thermal optimum, tolerance limits and thermal habitat. The database included 4442 samples mainly from Italian river catchments collected from the 1950s up to date. Thermal preferences were calculated separately for larval and pupal specimens and for different habitats: high altitude and lowland lakes in the Alpine ecoregion; lowland lakes in the Mediterranean ecoregion; heavily modified water bodies; kryal, krenal, rhithral and potamal in running waters. Optimum response was calculated as mean water temperature, weighted by species abundances; tolerance as weighted standard deviation; skewness and kurtosis as 3rd and 4th moment statistics. The responses were fitted to normal uni- or plurimodal Gaussian models. Cold stenothermal species showed: i unimodal response, ii tolerance for a narrow temperature range, iii optima closed to their minimum temperature values, iv leptokurtic response. Thermophilous species showed: i optima at different temperature values, ii wider tolerance, iii optima near their maximum temperature values, iv platikurtic response, often fitting a plurimodal model. As expected, lower optima values and narrower tolerance were obtained for kryal and krenal, than for rhithral, potamal and lakes. Thermal response curves were produced for each species and were discussed according to species distribution (i.e. altitudinal range in running water and water depth in lakes, voltinism and phylogeny. Thermal optimum and tolerance limits and the definition of the thermal habitat of species can help predicting the impact of global warming on freshwater ecosystems.

  6. Structural adaptation of the subunit interface of oligomeric thermophilic and hyperthermophilic enzymes.

    Science.gov (United States)

    Maugini, Elisa; Tronelli, Daniele; Bossa, Francesco; Pascarella, Stefano

    2009-04-01

    Enzymes from thermophilic and, particularly, from hyperthermophilic organisms are surprisingly stable. Understanding of the molecular origin of protein thermostability and thermoactivity attracted the interest of many scientist both for the perspective comprehension of the principles of protein structure and for the possible biotechnological applications through application of protein engineering. Comparative studies at sequence and structure levels were aimed at detecting significant differences of structural parameters related to protein stability between thermophilic and hyperhermophilic structures and their mesophilic homologs. Comparative studies were useful in the identification of a few recurrent themes which the evolution utilized in different combinations in different protein families. These studies were mostly carried out at the monomer level. However, maintenance of a proper quaternary structure is an essential prerequisite for a functional macromolecule. At the environmental temperatures experienced typically by hyper- and thermophiles, the subunit interactions mediated by the interface must be sufficiently stable. Our analysis was therefore aimed at the identification of the molecular strategies adopted by evolution to enhance interface thermostability of oligomeric enzymes. The variation of several structural properties related to protein stability were tested at the subunit interfaces of thermophilic and hyperthermophilic oligomers. The differences of the interface structural features observed between the hyperthermophilic and thermophilic enzymes were compared with the differences of the same properties calculated from pairwise comparisons of oligomeric mesophilic proteins contained in a reference dataset. The significance of the observed differences of structural properties was measured by a t-test. Ion pairs and hydrogen bonds do not vary significantly while hydrophobic contact area increases specially in hyperthermophilic interfaces. Interface

  7. Optimum design of steel structures

    CERN Document Server

    Farkas, József

    2013-01-01

    This book helps designers and manufacturers to select and develop the most suitable and competitive steel structures, which are safe, fit for production and economic. An optimum design system is used to find the best characteristics of structural models, which guarantee the fulfilment of design and fabrication requirements and minimize the cost function. Realistic numerical models are used as main components of industrial steel structures. Chapter 1 containts some experiences with the optimum design of steel structures Chapter 2 treats some newer mathematical optimization methods. Chapter 3 gives formulae for fabrication times and costs. Chapters 4 deals with beams and columns. Summarizes the Eurocode rules for design. Chapter 5 deals with the design of tubular trusses. Chapter 6 gives the design of frame structures and fire-resistant design rules for a frame. In Chapters 7 some minimum cost design problems of stiffened and cellular plates and shells are worked out for cases of different stiffenings and loads...

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

    DEFF Research Database (Denmark)

    Chang, Tinghong; Yao, Shuo

    2011-01-01

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

  9. Thermoascus aurantiacus is a promising source of enzymes for biomass deconstruction under thermophilic conditions

    Directory of Open Access Journals (Sweden)

    McClendon Shara D

    2012-07-01

    Full Text Available Abstract Background Thermophilic fungi have attracted increased interest for their ability to secrete enzymes that deconstruct biomass at high temperatures. However, development of thermophilic fungi as enzyme producers for biomass deconstruction has not been thoroughly investigated. Comparing the enzymatic activities of thermophilic fungal strains that grow on targeted biomass feedstocks has the potential to identify promising candidates for strain development. Thielavia terrestris and Thermoascus aurantiacus were chosen for characterization based on literature precedents. Results Thermoascus aurantiacus and Thielavia terrestris were cultivated on various biomass substrates and culture supernatants assayed for glycoside hydrolase activities. Supernatants from both cultures possessed comparable glycoside hydrolase activities when incubated with artificial biomass substrates. In contrast, saccharifications of ionic liquid pretreated switchgrass (Panicum virgatum revealed that T. aurantiacus enzymes released more glucose than T. terrestris enzymes over a range of protein mass loadings and temperatures. Temperature-dependent saccharifications demonstrated that the T. aurantiacus proteins retained higher levels of activity compared to a commercial enzyme mixture sold by Novozymes, Cellic CTec2, at elevated temperatures. Enzymes secreted by T. aurantiacus released glucose at similar protein loadings to CTec2 on dilute acid, ammonia fiber expansion, or ionic liquid pretreated switchgrass. Proteomic analysis of the T. aurantiacus culture supernatant revealed dominant glycoside hydrolases from families 5, 7, 10, and 61, proteins that are key enzymes in commercial cocktails. Conclusions T. aurantiacus produces a complement of secreted proteins capable of higher levels of saccharification of pretreated switchgrass than T. terrestris enzymes. The T. aurantiacus enzymatic cocktail performs at the same level as commercially available enzymatic cocktail for

  10. Thermoascus aurantiacus is a promising source of enzymes for biomass deconstruction under thermophilic conditions.

    Science.gov (United States)

    McClendon, Shara D; Batth, Tanveer; Petzold, Christopher J; Adams, Paul D; Simmons, Blake A; Singer, Steven W

    2012-07-28

    Thermophilic fungi have attracted increased interest for their ability to secrete enzymes that deconstruct biomass at high temperatures. However, development of thermophilic fungi as enzyme producers for biomass deconstruction has not been thoroughly investigated. Comparing the enzymatic activities of thermophilic fungal strains that grow on targeted biomass feedstocks has the potential to identify promising candidates for strain development. Thielavia terrestris and Thermoascus aurantiacus were chosen for characterization based on literature precedents. Thermoascus aurantiacus and Thielavia terrestris were cultivated on various biomass substrates and culture supernatants assayed for glycoside hydrolase activities. Supernatants from both cultures possessed comparable glycoside hydrolase activities when incubated with artificial biomass substrates. In contrast, saccharifications of ionic liquid pretreated switchgrass (Panicum virgatum) revealed that T. aurantiacus enzymes released more glucose than T. terrestris enzymes over a range of protein mass loadings and temperatures. Temperature-dependent saccharifications demonstrated that the T. aurantiacus proteins retained higher levels of activity compared to a commercial enzyme mixture sold by Novozymes, Cellic CTec2, at elevated temperatures. Enzymes secreted by T. aurantiacus released glucose at similar protein loadings to CTec2 on dilute acid, ammonia fiber expansion, or ionic liquid pretreated switchgrass. Proteomic analysis of the T. aurantiacus culture supernatant revealed dominant glycoside hydrolases from families 5, 7, 10, and 61, proteins that are key enzymes in commercial cocktails. T. aurantiacus produces a complement of secreted proteins capable of higher levels of saccharification of pretreated switchgrass than T. terrestris enzymes. The T. aurantiacus enzymatic cocktail performs at the same level as commercially available enzymatic cocktail for biomass deconstruction, without strain development or

  11. Biological hydrogen production by moderately thermophilic anaerobic bacteria

    International Nuclear Information System (INIS)

    HP Goorissen; AJM Stams

    2006-01-01

    This study focuses on the biological production of hydrogen at moderate temperatures (65-75 C) by anaerobic bacteria. A survey was made to select the best (moderate) thermophiles for hydrogen production from cellulolytic biomass. From this survey we selected Caldicellulosiruptor saccharolyticus (a gram-positive bacterium) and Thermotoga elfii (a gram-negative bacterium) as potential candidates for biological hydrogen production on mixtures of C 5 -C 6 sugars. Xylose and glucose were used as model substrates to describe growth and hydrogen production from hydrolyzed biomass. Mixed substrate utilization in batch cultures revealed differences in the sequence of substrate consumption and in catabolites repression of the two microorganisms. The regulatory mechanisms of catabolites repression in these microorganisms are not known yet. (authors)

  12. Efficient utilization of xylanase and lipase producing thermophilic ...

    African Journals Online (AJOL)

    Efficient utilization of xylanase and lipase producing thermophilic marine actinomycetes ( Streptomyces albus and Streptomyces hygroscopicus ) in the production of ecofriendly alternative energy from waste.

  13. Cellulases from Thermophilic Fungi: Recent Insights and Biotechnological Potential

    Directory of Open Access Journals (Sweden)

    Duo-Chuan Li

    2011-01-01

    Full Text Available Thermophilic fungal cellulases are promising enzymes in protein engineering efforts aimed at optimizing industrial processes, such as biomass degradation and biofuel production. The cloning and expression in recent years of new cellulase genes from thermophilic fungi have led to a better understanding of cellulose degradation in these species. Moreover, crystal structures of thermophilic fungal cellulases are now available, providing insights into their function and stability. The present paper is focused on recent progress in cloning, expression, regulation, and structure of thermophilic fungal cellulases and the current research efforts to improve their properties for better use in biotechnological applications.

  14. Avoiding dangerous missense: thermophiles display especially low mutation rates.

    Directory of Open Access Journals (Sweden)

    John W Drake

    2009-06-01

    Full Text Available Rates of spontaneous mutation have been estimated under optimal growth conditions for a variety of DNA-based microbes, including viruses, bacteria, and eukaryotes. When expressed as genomic mutation rates, most of the values were in the vicinity of 0.003-0.004 with a range of less than two-fold. Because the genome sizes varied by roughly 10(4-fold, the mutation rates per average base pair varied inversely by a similar factor. Even though the commonality of the observed genomic rates remains unexplained, it implies that mutation rates in unstressed microbes reach values that can be finely tuned by evolution. An insight originating in the 1920s and maturing in the 1960s proposed that the genomic mutation rate would reflect a balance between the deleterious effect of the average mutation and the cost of further reducing the mutation rate. If this view is correct, then increasing the deleterious impact of the average mutation should be countered by reducing the genomic mutation rate. It is a common observation that many neutral or nearly neutral mutations become strongly deleterious at higher temperatures, in which case they are called temperature-sensitive mutations. Recently, the kinds and rates of spontaneous mutations were described for two microbial thermophiles, a bacterium and an archaeon. Using an updated method to extrapolate from mutation-reporter genes to whole genomes reveals that the rate of base substitutions is substantially lower in these two thermophiles than in mesophiles. This result provides the first experimental support for the concept of an evolved balance between the total genomic impact of mutations and the cost of further reducing the basal mutation rate.

  15. 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.

  16. 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

  17. Development of a gene cloning system in a fast-growing and moderately thermophilic Streptomyces species and heterologous expression of Streptomyces antibiotic biosynthetic gene clusters

    Science.gov (United States)

    2011-01-01

    Background Streptomyces species are a major source of antibiotics. They usually grow slowly at their optimal temperature and fermentation of industrial strains in a large scale often takes a long time, consuming more energy and materials than some other bacterial industrial strains (e.g., E. coli and Bacillus). Most thermophilic Streptomyces species grow fast, but no gene cloning systems have been developed in such strains. Results We report here the isolation of 41 fast-growing (about twice the rate of S. coelicolor), moderately thermophilic (growing at both 30°C and 50°C) Streptomyces strains, detection of one linear and three circular plasmids in them, and sequencing of a 6996-bp plasmid, pTSC1, from one of them. pTSC1-derived pCWH1 could replicate in both thermophilic and mesophilic Streptomyces strains. On the other hand, several Streptomyces replicons function in thermophilic Streptomyces species. By examining ten well-sporulating strains, we found two promising cloning hosts, 2C and 4F. A gene cloning system was established by using the two strains. The actinorhodin and anthramycin biosynthetic gene clusters from mesophilic S. coelicolor A3(2) and thermophilic S. refuineus were heterologously expressed in one of the hosts. Conclusions We have developed a gene cloning and expression system in a fast-growing and moderately thermophilic Streptomyces species. Although just a few plasmids and one antibiotic biosynthetic gene cluster from mesophilic Streptomyces were successfully expressed in thermophilic Streptomyces species, we expect that by utilizing thermophilic Streptomyces-specific promoters, more genes and especially antibiotic genes clusters of mesophilic Streptomyces should be heterologously expressed. PMID:22032628

  18. A comparative study of thermophilic and mesophilic anaerobic co-digestion of food waste and wheat straw: Process stability and microbial community structure shifts.

    Science.gov (United States)

    Shi, Xuchuan; Guo, Xianglin; Zuo, Jiane; Wang, Yajiao; Zhang, Mengyu

    2018-05-01

    Renewable energy recovery from organic solid waste via anaerobic digestion is a promising way to provide sustainable energy supply and eliminate environmental pollution. However, poor efficiency and operational problems hinder its wide application of anaerobic digestion. The effects of two key parameters, i.e. temperature and substrate characteristics on process stability and microbial community structure were studied using two lab-scale anaerobic reactors under thermophilic and mesophilic conditions. Both the reactors were fed with food waste (FW) and wheat straw (WS). The organic loading rates (OLRs) were maintained at a constant level of 3 kg VS/(m 3 ·d). Five different FW:WS substrate ratios were utilized in different operational phases. The synergetic effects of co-digestion improved the stability and performance of the reactors. When FW was mono-digested, both reactors were unstable. The mesophilic reactor eventually failed due to volatile fatty acid accumulation. The thermophilic reactor had better performance compared to mesophilic one. The biogas production rate of the thermophilic reactor was 4.9-14.8% higher than that of mesophilic reactor throughout the experiment. The shifts in microbial community structures throughout the experiment in both thermophilic and mesophilic reactors were investigated. With increasing FW proportions, bacteria belonging to the phylum Thermotogae became predominant in the thermophilic reactor, while the phylum Bacteroidetes was predominant in the mesophilic reactor. The genus Methanosarcina was the predominant methanogen in the thermophilic reactor, while the genus Methanothrix remained predominant in the mesophilic reactor. The methanogenesis pathway shifted from acetoclastic to hydrogenotrophic when the mesophilic reactor experienced perturbations. Moreover, the population of lignocellulose-degrading microorganisms in the thermophilic reactor was higher than those in mesophilic reactor, which explained the better

  19. High ethanol tolerance of the thermophilic anaerobic ethanol producer Thermoanaerobacter BG1L1

    DEFF Research Database (Denmark)

    Georgieva, Tania I.; Mikkelsen, Marie Just; Ahring, Birgitte Kiær

    2007-01-01

    The low ethanol tolerance of thermophilic anaerobic bacteria, generally less than 2% (v/v) ethanol, is one of the main limiting factors for their potential use for second generation fuel ethanol production. In this work, the tolerance of thermophilic anaerobic bacterium Thermoanaerobacter BG 1L1...... to exogenously added ethanol was studied in a continuous immobilized reactor system at a growth temperature of 70 degrees C. Ethanol tolerance was evaluated based on inhibition of fermentative performance e.g.. inhibition of substrate conversion. At the highest ethanol concentration tested (8.3% v/v), the strain...... was able to convert 42% of the xylose initially present, indicating that this ethanol concentration is not the upper limit tolerated by the strain. Long-term strain adaptation to high ethanol concentrations (6 - 8.3%) resulted in an improvement of xylose conversion by 25% at an ethanol concentration of 5...

  20. 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......, fermentation, and sulfate reduction upon induction at 50°C. The closest relatives to these bacteria come from warm subsurface petroleum reservoir and ocean crust ecosystems, suggesting that seabed fluid flow from these environments is delivering thermophiles to the cold ocean. These transport pathways may...

  1. The Activity of Cellulase from Thermophilic Fungi Isolated from CaneBagasses

    International Nuclear Information System (INIS)

    Aris-Toharisman; Akyunul-Jannah

    2000-01-01

    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 o C. 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 o C. However,thermophilic fungi may be potential to be exploited in lignocellulosedegradation at the tropical areas as the process usually needs temperature ofabove 50 o C. (author)

  2. 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...... wastes at 70 degrees C. The enriched mixed culture consisted of two rod-shaped bacterial members growing at an optimal temperature of 80 degrees C and an optimal pH 8.1. The culture was able to utilize glucose, galactose, mannose, xylose, arabinose, maltose, sucrose, pyruvate and glycerol as carbon...... sources. Growth on glucose produced acetate, H-2 and carbon dioxide. Maximal H-2 production rate on glucose was 1.1 mmol l(-1) h(-1) with a maximum H-2 yield of 1.9 mole H-2 per mole glucose. 16S ribosomal DNA clone library analyses showed that the culture members were phylogenetically affiliated...

  3. Novel Anoxybacillus flavithermus AK1: A Thermophile Isolated from a Hot Spring in Saudi Arabia

    KAUST Repository

    Khalil, Amjad

    2017-06-14

    Anoxybacillus flavithermus AK1 is a thermophilic bacterium that is able to survive at temperatures ranging from 55 to 60∘C. The AK1 strain was isolated from the hot spring “Al-Ain Alhara” located at a distance of 50 km southeast of the city of Gazan, Saudi Arabia. This study presents the morphological characterization of A. flavithermus AK1, including a detailed description of its complete genome sequence. A total of 50 contigs were used to produce a genome sequence of 2,630,664 bp that includes 2724 protein-coding genes and 75 RNA genes, 18 of which are rRNA genes. A comparison of this genome sequence with those of Anoxybacillus flavithermus strains that were previously submitted to NCBI revealed that the AK1 strain has the smallest genome size with the highest GC content. The strain can therefore be exploited for several biotechnological applications based on its high thermophilic potential.

  4. Community phylogenetic analysis of moderately thermophilic cyanobacterial mats from China, the Philippines and Thailand.

    Science.gov (United States)

    Hongmei, Jing; Aitchison, Jonathan C; Lacap, Donnabella C; Peerapornpisal, Yuwadee; Sompong, Udomluk; Pointing, Stephen B

    2005-08-01

    Most community molecular studies of thermophilic cyanobacterial mats to date have focused on Synechococcus occurring at temperatures of approximately 50-65 degrees C. These reveal that molecular diversity exceeds that indicated by morphology, and that phylogeographic lineages exist. The moderately thermophilic and generally filamentous cyanobacterial mat communities occurring at lower temperatures have not previously been investigated at the community molecular level. Here we report community diversity in mats of 42-53 degrees C recovered from previously unstudied geothermal locations. Separation of 16S rRNA gene-defined genotypes from community DNA was achieved by DGGE. Genotypic diversity was greater than morphotype diversity in all mats sampled, although genotypes generally corresponded to observed morphotypes. Thirty-six sequences were recovered from DGGE bands. Phylogenetic analyses revealed these to form novel thermophilic lineages distinct from their mesophilic counterparts, within Calothrix, Cyanothece, Fischerella, Phormidium, Pleurocapsa, Oscillatoria and Synechococcus. Where filamentous cyanobacterial sequences belonging to the same genus were recovered from the same site, these were generally closely affiliated. Location-specific sequences were observed for some genotypes recovered from geochemically similar yet spatially separated sites, thus providing evidence for phylogeographic lineages that evolve in isolation. Other genotypes were more closely affiliated to geographically remote counterparts from similar habitats suggesting that adaptation to certain niches is also important.

  5. 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.

  6. Screening of thermotolerant and thermophilic fungi aiming β-xylosidase and arabinanase production.

    Science.gov (United States)

    Benassi, Vivian Machado; de Lucas, Rosymar Coutinho; Jorge, João Atílio; Polizeli, Maria de Lourdes Teixeira de Moraes

    2014-01-01

    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 °C, suggesting a thermophilic or thermotolerant character. Additionally Aspergillus thermomutatus anamorph of Neosartorya and A. parasiticus grew at 50 °C. 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 °C), while the correspondent extracellular activities were favorably secreted from cultures at 30 °C. 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.

  7. The Feasibility of Thermophilic Caldimonas manganoxidans as a Platform for Efficient PHB Production.

    Science.gov (United States)

    Hsiao, Li-Jung; Lin, Ji-Hong; Sankatumvong, Pantitra; Wu, Tzong-Ming; Li, Si-Yu

    2016-11-01

    Recently, poly(3-hydroxybutyrate) (PHB) has been found in a few thermophilic strains where several advantages can be gained from running fermentation at high temperatures. Caldimonas manganoxidans, a thermophilic gram-negative bacterium, was investigated for the feasibility as a PHB-producing strain. It is suggested that the best fermentation strategy for achieving the highest PHB concentration of 5.4 ± 1.1 g/L (from 20 g/L glucose) in 24 h is to use the fermentation conditions that are favored for the bacterial growth, yet temperature and pH should be chosen at conditions that are favored for the PHB content. Besides, the above fermentation conditions produce PHB that has a high molecular weight of 1274 kDa with a low polydispersity index (PDI) of 1.45, where the highest Mw of PHB of 1399 kDa (PDI of 1.32) is obtained in this study. To the best knowledge of authors, C. manganoxidans has the best PHB productivity among the thermophiles and is comparable to those common PHB-producing mesophiles.

  8. Screening of thermotolerant and thermophilic fungi aiming β-xylosidase and arabinanase production

    Science.gov (United States)

    Benassi, Vivian Machado; de Lucas, Rosymar Coutinho; Jorge, João Atílio; Polizeli, Maria de Lourdes Teixeira de Moraes

    2014-01-01

    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 °C, suggesting a thermophilic or thermotolerant character. Additionally Aspergillus thermomutatus anamorph of Neosartorya and A. parasiticus grew at 50 °C. 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 °C), while the correspondent extracellular activities were favorably secreted from cultures at 30 °C. 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. PMID:25763055

  9. Heat Stable Enzymes from Thermophiles

    Science.gov (United States)

    1998-02-01

    activity fell dramatically, as would be expected. Envirofirst is sodium carbonate peroxyhydrate produced by Solvay . It is an inorganic peroxide and was...Mix and hold at room temperature for 5 min. 2. Add 2.5 ml 20% NaCl. 3. Mix gently for 30 min at 55 °C. 4. Add 0.25 gm sodium carbonate . 5. Mix gently...from the literature 28 Carbon source 28 Nitrogen source 32 Trace elements 33 Other components 34 Fermentation temperature 38 Time course 38 Inoculation

  10. Alcohol dehydrogenases from thermophilic and hyperthermophilic archaea and bacteria.

    Science.gov (United States)

    Radianingtyas, Helia; Wright, Phillip C

    2003-12-01

    Many studies have been undertaken to characterise alcohol dehydrogenases (ADHs) from thermophiles and hyperthermophiles, mainly to better understand their activities and thermostability. To date, there are 20 thermophilic archaeal and 17 thermophilic bacterial strains known to have ADHs or similar enzymes, including the hypothetical proteins. Some of these thermophiles are found to have multiple ADHs, sometimes of different types. A rigid delineation of amino acid sequences amongst currently elucidated thermophilic ADHs and similar proteins is phylogenetically apparent. All are NAD(P)-dependent, with one exception that utilises the cofactor F(420) instead. Within the NAD(P)-dependent group, the thermophilic ADHs are orderly clustered as zinc-dependent ADHs, short-chain ADHs, and iron-containing/activated ADHs. Distance matrix calculations reveal that thermophilic ADHs within one type are homologous, with those derived from a single genus often showing high similarities. Elucidation of the enzyme activity and stability, coupled with structure analysis, provides excellent information to explain the relationship between them, and thermophilic ADHs diversity.

  11. Domestic sewage sludge composting in a rotary drum reactor: optimizing the thermophilic stage.

    Science.gov (United States)

    Rodríguez, Luis; Cerrillo, María I; García-Albiach, Valentín; Villaseñor, José

    2012-12-15

    The aim of this paper was to study the influence of four process variables (turning frequency, gas-phase oxygen level, type of bulking agent and sludge/bulking agent mixing ratio) on the performance of the sewage sludge composting process using a rotary drum pilot scale reactor, in order to optimize the thermophilic stage and reduce the processing time. Powdered sawdust, wood shavings, wood chips, prunings waste and straw were used as bulking agents and the thermophilic stage temperature profile was used as the main indicator for gauging if the composting process was developing correctly. Our results showed that a 12 h(-1) turning frequency and an oxygen concentration of 10% were the optimal conditions for the composting process to develop. The best results were obtained by mixing the sewage sludge with wood shavings in a 3:1 w/w ratio (on a wet basis), which adapted the initial moisture content and porosity to an optimal range and led to a maximum temperature of 70 °C being reached thus ensuring the complete removal of pathogens. Moisture, C:N ratio, pH, organic matter, heavy metals, pathogens and stability were all analysed for every mixture obtained at the end of the thermophilic stage. These parameters were compared with the limits established by the Spanish regulation on fertilizers (RD 824/2005) in order to assess if the compost obtained could be used on agricultural soils. The right combination of having optimal process variables combined with an appropriate reactor design allowed the thermophilic stage of the composting process to be speeded up, hence obtaining a compost product, after just two weeks of processing that (with the exception of the moisture content) complied with the Spanish legal requirements for fertilizers, without requiring a later maturation stage. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Optimum coolant chemistry in BWRs

    International Nuclear Information System (INIS)

    Lin, C.C.; Cowan, R.L.; Kiss, E.

    2004-01-01

    LWR water chemistry parameters are directly or indirectly related to the plant's operational performance and for a significant amount of Operation and Maintenance (O and M) costs. Obvious impacts are the operational costs associated with water treatment, monitoring and associated radwaste generation. Less obvious is the important role water chemistry plays in the magnitude of drywell shutdown dose rates, fuel corrosion performance and, (probably most importantly) materials degradation such as from stress corrosion cracking of piping and Reactor Pressure Vessel (RPV) internal components. To improve the operational excellence of the BWR and to minimize the impact of water chemistry on O and M costs. General Electric has developed the concept of Optimum Water Chemistry (OWC). The 'best practices' and latest technology findings from the U.S., Asia and Europe are integrated into the suggested OWC Specification. This concept, together with cost effective ways to meet the requirement, are discussed. (author)

  13. Characterization of poly(L-lactide)-degrading enzyme produced by thermophilic filamentous bacteria Laceyella sacchari LP175.

    Science.gov (United States)

    Hanphakphoom, Srisuda; Maneewong, Narisara; Sukkhum, Sukhumaporn; Tokuyama, Shinji; Kitpreechavanich, Vichien

    2014-01-01

    Eleven strains of poly(L-lactide) (PLLA)-degrading thermophilic bacteria were isolated from forest soils and selected based on clear zone formation on an emulsified PLLA agar plate at 50°C. Among the isolates, strain LP175 showed the highest PLLA-degrading ability. It was closely related to Laceyella sacchari, with 99.9% similarity based on the 16S rRNA gene sequence. The PLLA-degrading enzyme produced by the strain was purified to homogeneity by 48.1% yield and specific activity of 328 U·mg-protein-1 with a 15.3-fold purity increase. The purified enzyme was strongly active against specific substrates such as casein and gelatin and weakly active against Suc-(Ala)₃-pNA. Optimum enzyme activity was exhibited at a temperature of 60°C with thermal stability up to 50°C and a pH of 9.0 with pH stability in a range of 8.5-10.5. Molecular weight of the enzyme was approximately 28.0 kDa, as determined by gel filtration and SDS-PAGE. The inhibitors phenylmethylsulfonyl fluoride (PMSF), ethylenediaminetetraacetate (EDTA), and ethylene glycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA) strongly inhibited enzyme activity, but the activity was not inhibited by 1 mM 1,10-phenanthroline (1,10-phen). The N-terminal amino acid sequences had 100% homology with thermostable serine protease (thermitase) from Thermoactinomyces vulgaris. The results obtained suggest that the PLLA-degrading enzyme produced by L. sacchari strain LP175 is serine protease.

  14. Purification and Properties of Polygalacturonase Produced by Thermophilic Fungus Thermoascus aurantiacus CBMAI-756 on Solid-State Fermentation

    Directory of Open Access Journals (Sweden)

    Eduardo da Silva Martins

    2013-01-01

    Full Text Available Polygalacturonases are enzymes involved in the degradation of pectic substances, being extensively used in food industries, textile processing, degumming of plant rough fibres, and treatment of pectic wastewaters. Polygalacturonase (PG production by thermophilic fungus Thermoascus aurantiacus on solid-state fermentation was carried out in culture media containing sugar cane bagasse and orange bagasse in proportions of 30% and 70% (w/w at 45°C for 4 days. PG obtained was purified by gel filtration and ion-exchange chromatography. The highest activity was found between pH 4.5 and 5.5, and the enzyme preserved more than 80% of its activity at pH values between 5.0 and 6.5. At pH values between 3.0 and 4.5, PG retained about 73% of the original activity, whereas at pH 10.0 it remained around 44%. The optimum temperature was 60–65°C. The enzyme was completely stable when incubated for 1 hour at 50°C. At 55°C and 60°C, the activity decreased 55% and 90%, respectively. The apparent molecular weight was 29.3 kDa, Km of 1.58 mg/mL and Vmax of 1553.1 μmol/min/mg. The presence of Zn+2, Mn+2, and Hg+2 inhibited 59%, 77%, and 100% of enzyme activity, respectively. The hydrolysis product suggests that polygalacturonase was shown to be an endo/exoenzyme.

  15. Thermosyntropha lipolytica gen. nov., sp. nov., a lipolytic, anaerobic, alkalitolerant, thermophilic bacterium utilizing short- and long-chain fatty acids in syntrophic coculture with a methanogenic archaeum.

    Science.gov (United States)

    Svetlitshnyi, V; Rainey, F; Wiegel, J

    1996-10-01

    Three strains of an anaerobic thermophilic organoheterotrophic lipolytic alkalitolerant bacterium, Thermosyntropha lipolytica gen. nov., sp. nov. (type strain JW/VS-265T; DSM 11003), were isolated from alkaline hot springs of Lake Bogoria (Kenya). The cells were nonmotile, non-spore forming, straight or slightly curved rods. At 60 degrees C the pH range for growth determined at 25 degrees C [pH25 degrees C] was 7.15 to 9.5, with an optimum between 8.1 and 8.9 (pH60 degrees C of 7.6 and 8.1). At a pH25 degrees C of 8.5 the temperature range for growth was from 52 to 70 degrees C, with an optimum between 60 and 66 degrees C. The shortest doubling time was around 1 h. In pure culture the bacterium grew in a mineral base medium supplemented with yeast extract, tryptone, Casamino Acids, betaine, and crotonate as carbon sources, producing acetate as a major product and constitutively a lipase. During growth in the presence of olive oil, free long-chain fatty acids were accumulated in the medium but the pure culture could not utilize olive oil, triacylglycerols, short- and long-chain fatty acids, and glycerol for growth. In syntrophic coculture (Methanobacterium strain JW/VS-M29) the lipolytic bacteria grew on triacylglycerols and linear saturated and unsaturated fatty acids with 4 to 18 carbon atoms, but glycerol was not utilized. Fatty acids with even numbers of carbon atoms were degraded to acetate and methane, while from odd-numbered fatty acids 1 mol of propionate per mol of fatty acid was additionally formed. 16S rDNA sequence analysis identified Syntrophospora and Syntrophomonas spp. as closest phylogenetic neighbors.

  16. 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.

  17. Use of thermophilic bacteria for bioremediation of petroleum contaminants

    International Nuclear Information System (INIS)

    Al-Maghrabi, I.M.A.; Bin Aqil, A.O.; Chaalal, O.; Islam, M.R.

    1999-01-01

    Several strains of thermophilic bacteria were isolated from the environment of the United Arab Emirates. These bacteria show extraordinary resistance to heat and have their maximum growth rate around 60--80 C. This article investigates the potential of using these facultative bacteria for both in situ and ex situ bioremediation of petroleum contaminants. In a series of batch experiments, bacterial growth was observed using a computer image analyzer following a recently developed technique. These experiments showed clearly that the growth rate is enhanced in the presence of crude oil. This is coupled with a rapid degradation of the crude oil. These bacteria were found to be ideal for breaking down long-chain organic molecules at a temperature of 40 C, which is the typical ambient temperature of the Persian Gulf region. The same strains of bacteria are also capable of surviving in the presence of the saline environment that can prevail in both sea water and reservoir connate water. This observation prompted further investigation into the applicability of the bacteria in microbial enhanced oil recovery. In the United Arab Emirates, the reservoirs are typically at a temperature of around 85 C. Finally, the performance of the bacteria is tested in a newly developed bioreactor that uses continuous aeration through a transverse slotted pipe. This reactor also uses mixing without damaging the filamentous bacteria. In this process, the mechanisms of bioremediation are identified

  18. Nicotinamidase from the thermophilic archaeon Acidilobus saccharovorans: structural and functional characteristics.

    Science.gov (United States)

    Stekhanova, T N; Bezsudnova, E Y; Mardanov, A V; Osipov, E M; Ravin, N V; Skryabin, K G; Popov, V O

    2014-01-01

    Nicotinamidase is involved in the maintenance of NAD+ homeostasis and in the NAD+ salvage pathway of most prokaryotes, and it is considered as a possible drug target. The gene (ASAC_0847) encoding a hypothetical nicotinamidase has been found in the genome of the thermophilic archaeon Acidilobus saccharovorans. The product of this gene, NA_As0847, has been expressed in Escherichia coli, isolated, and characterized as a Fe(2+)-containing nicotinamidase (k(cat)/K(m) = 427 mM(-1)·sec(-1))/pyrazinamidase (k(cat)/K(m) = 331 mM(-1)·sec(-1)). NA_As0847 is a homodimer with molecular mass 46.4 kDa. The enzyme has high thermostability (T(1/2) (60°C) = 180 min, T(1/2) (80°C) = 35 min) and thermophilicity (T(opt) = 90°C, E(a) = 30.2 ± 1.0 kJ/mol) and broad pH interval of activity, with the optimum at pH 7.5. Special features of NA_As0847 are the presence of Fe2+ instead of Zn2+ in the active site of the enzyme and inhibition of the enzyme activity by Zn2+ at micromolar concentrations. Analysis of the amino acid sequence revealed a new motif of the metal-binding site (DXHXXXDXXEXXXWXXH) for homological archaeal nicotinamidases.

  19. Effects of constant and stepwise changes in temperature on the species abundance dynamics of four cladocera species

    Directory of Open Access Journals (Sweden)

    Verbitsky V. B.

    2011-09-01

    Full Text Available Laboratory experiments with natural zooplankton communities were carried out to study the effects of two contrasting temperature regimes: constant temperature (15, 20, and 25 °C and graded changes in temperature. The graded regime consisted of repeated sustained (three weeks controlled stepwise temperature changes of 5 or 10 °C within 15–25 °C on the population dynamics of four dominant species of lake littoral zooplankton, Daphnia longispina (Müller, 1785, Diaphanosoma brachyurum (Lievin, 1848, Simocephalus vetulus (Müller, 1776 and Chydorus sphaericus (Müller, 1785. The results show that controlled stepwise changes (positive or negative in temperature within the ranges of 15–20, 20–25, and 15–25 °C can exert either stimulating or inhibitory effect (direct or delayed on the development of D. longispina and S. vetulus populations. The development of D. brachyurum and Ch. sphaericus, both more steno-thermophile, was only stimulated by a stable elevated temperature (25 °C. These results support the previously formulated hypothesis that, in determining the ecological temperature optimum of a species within a natural community, it is not enough to define its optimum from constant, cyclic or random temperature fluctuations, but also from unidirectional stepwise changes in temperature. These stepwise changes may also induce prolonged or delayed effects.

  20. 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.

  1. Genome sequence and transcriptome analyses of the thermophilic zygomycete fungus Rhizomucor miehei.

    Science.gov (United States)

    Zhou, Peng; Zhang, Guoqiang; Chen, Shangwu; Jiang, Zhengqiang; Tang, Yanbin; Henrissat, Bernard; Yan, Qiaojuan; Yang, Shaoqing; Chen, Chin-Fu; Zhang, Bing; Du, Zhenglin

    2014-04-21

    The zygomycete fungi like Rhizomucor miehei have been extensively exploited for the production of various enzymes. As a thermophilic fungus, R. miehei is capable of growing at temperatures that approach the upper limits for all eukaryotes. To date, over hundreds of fungal genomes are publicly available. However, Zygomycetes have been rarely investigated both genetically and genomically. Here, we report the genome of R. miehei CAU432 to explore the thermostable enzymatic repertoire of this fungus. The assembled genome size is 27.6-million-base (Mb) with 10,345 predicted protein-coding genes. Even being thermophilic, the G + C contents of fungal whole genome (43.8%) and coding genes (47.4%) are less than 50%. Phylogenetically, R. miehei is more closerly related to Phycomyces blakesleeanus than to Mucor circinelloides and Rhizopus oryzae. The genome of R. miehei harbors a large number of genes encoding secreted proteases, which is consistent with the characteristics of R. miehei being a rich producer of proteases. The transcriptome profile of R. miehei showed that the genes responsible for degrading starch, glucan, protein and lipid were highly expressed. The genome information of R. miehei will facilitate future studies to better understand the mechanisms of fungal thermophilic adaptation and the exploring of the potential of R. miehei in industrial-scale production of thermostable enzymes. Based on the existence of a large repertoire of amylolytic, proteolytic and lipolytic genes in the genome, R. miehei has potential in the production of a variety of such enzymes.

  2. Acquired thermotolerance and heat shock in the extremely thermophilic archaebacterium Sulfolobus sp. strain B12.

    OpenAIRE

    Trent, J D; Osipiuk, J; Pinkau, T

    1990-01-01

    The extreme thermophile Sulfolobus sp. strain B12 exhibits an acquired thermotolerance response. Thus, survival of cells from a 70 degrees C culture at the lethal temperature of 92 degrees C was enhanced by as much as 6 orders of magnitude over a 2-h period if the culture was preheated to 88 degrees C for 60 min or longer before being exposed to the lethal temperature. In eubacteria and eucaryotes, acquired thermotolerance correlates with the induced synthesis of a dozen or so proteins known ...

  3. On the optimum energy mix

    International Nuclear Information System (INIS)

    Fujii, Yasumasa

    2011-01-01

    After the Fukushima accident occurred in March 2011, reform of Japan's basic energy plan and energy supply system was reported to be under discussion such as to reduce dependence on nuclear power. Planning of energy policy should be considered based on four evaluation indexes of 'economics'. 'environmental effects', 'stable supply of energy' and 'sustainability'. 'Stable supply of energy' should include stability of domestic energy supply infrastructure against natural disasters in addition to stable supply of overseas resources. 'Sustainability' meant long-term availability of resources. Since there did not exist an almighty energy source and energy supply system superior in terms of every above-mentioned evaluation index, it would be wise to use combining various energy sources and supply system in rational way. This combination lead to optimum energy mix, so-called 'Energy Best Mix'. The author evaluated characteristics of energy sources and energy supply system in terms of four indexes and showed best energy mix from short-, medium- and long-term perspectives. Since fossil fuel resources would deplete anyhow, it would be inevitable for human being to be dependent on non-fossil energy resources regardless of greenhouse effects. At present it would be difficult and no guarantee to establish society fully dependent on renewable energy, then it would be probable to need utilization of nuclear energy in the long term. (T. Tanaka)

  4. 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

  5. Thermophilic slurry-phase treatment of petroleum hydrocarbon waste sludges

    International Nuclear Information System (INIS)

    Castaldi, F.J.; Bombaugh, K.J.; McFarland, B.

    1995-01-01

    Chemoheterotrophic thermophilic bacteria were used to achieve enhanced hydrocarbon degradation during slurry-phase treatment of oily waste sludges from petroleum refinery operations. Aerobic and anaerobic bacterial cultures were examined under thermophilic conditions to assess the effects of mode of metabolism on the potential for petroleum hydrocarbon degradation. The study determined that both aerobic and anaerobic thermophilic bacteria are capable of growth on petroleum hydrocarbons. Thermophilic methanogenesis is feasible during the degradation of hydrocarbons when a strict anaerobic condition is achieved in a slurry bioreactor. Aerobic thermophilic bacteria achieved the largest apparent reduction in chemical oxygen demand, freon extractable oil, total and volatile solid,s and polycyclic aromatic hydrocarbons (PAHs) when treating oily waste sludges. The observed shift with time in the molecular weight distribution of hydrocarbon material was more pronounced under aerobic metabolic conditions than under strict anaerobic conditions. The changes in the hydrocarbon molecular weight distribution, infrared spectra, and PAH concentrations during slurry-phase treatment indicate that the aerobic thermophilic bioslurry achieved a higher degree of hydrocarbon degradation than the anaerobic thermophilic bioslurry during the same time period

  6. Thermophilic fungi in the new age of fungal taxonomy.

    Science.gov (United States)

    de Oliveira, Tássio Brito; Gomes, Eleni; Rodrigues, Andre

    2015-01-01

    Thermophilic fungi are of wide interest due to their potential to produce heat-tolerant enzymes for biotechnological processes. However, the taxonomy of such organisms remains obscure, especially given new developments in the nomenclature of fungi. Here, we examine the taxonomy of the thermophilic fungi most commonly used in industry in light of the recent taxonomic changes following the adoption of the International Code of Nomenclature for Algae, Fungi and Plants and also based on the movement One Fungus = One Name. Despite the widespread use of these fungi in applied research, several thermotolerant fungi still remain classified as thermophiles. Furthermore, we found that while some thermophilic fungi have had their genomes sequenced, many taxa still do not have barcode sequences of reference strains available in public databases. This lack of basic information is a limiting factor for the species identification of thermophilic fungi and for metagenomic studies in this field. Based on next-generation sequencing, such studies generate large amounts of data, which may reveal new species of thermophilic fungi in different substrates (composting systems, geothermal areas, piles of plant material). As discussed in this study, there are intrinsic problems associated with this method, considering the actual state of the taxonomy of thermophilic fungi. To overcome such difficulties, the taxonomic classification of this group should move towards standardizing the commonly used species names in industry and to assess the possibility of including new systems for describing species based on environmental sequences.

  7. Temperature of optimum generation in facilities of solar cold making use of the equation characteristic; Temperatura de generacion optima en instalaciones de frio solar haciendo uso de la ecuacion caracteristica

    Energy Technology Data Exchange (ETDEWEB)

    Leucona, A.; Ventas, R.; Venegas, M. del C.; Zacarias, A.; Salgado, R.

    2008-07-01

    Absorption machines show a similar response as a function of the external temperatures, which can be approximated by a single functional dependence of the named characteristic temperature. This equation and the normalization curve of the solar thermal collector field driving the chiller and some more approximations allow determining the driving temperature that maximizes the cooling power at any time. This results in a simple equation. It is offered for the design of solar cooling facilities and their control algorithms. Some results are offered and discussed. (Author)

  8. Influence of variable feeding on mesophilic and thermophilic co-digestion of Laminaria digitata and cattle manure

    International Nuclear Information System (INIS)

    Sarker, Shiplu; Møller, Henrik Bjarne; Bruhn, Annette

    2014-01-01

    Highlights: • Anaerobic co-digestion of L. digitata and cattle manure, at ∼35 and ∼50 °C. • Mesophilic co-digestion showed somewhat stable specific methane, but increased volumetric yield. • Thermophilic co-digester yielded higher methane at higher input of algae compared to control. • Mesophilic co-digester performed better in terms of various parameters except methane yield. - Abstract: In this study the effect of various feeding ratios on mesophilic (∼35 °C) and thermophilic (∼50 °C) co-digestion of brown algae Laminaria digitata and cattle manure was investigated. Algae input of 15% VS caused no influence on specific methane yield from mesophilic co-digester while deteriorated the process parameters such as the development of propionic acid in total volatile fatty acids (tVFA) pattern of the thermophilic co-digester. The accumulation of tVFA continued for the latter reactor as the feeding ratio of algae enhanced to 24% VS, but the specific methane yield improved dramatically. Same rise in feeding once again showed no improvement in specific methane yield from mesophilic co-digester even though the other process parameters stabilized or, enriched such as the gain in average volumetric methane yield. For the last feeding ratio at 41% VS algae, specific methane yield from mesophilic co-digester slightly increased which however was not still comparable with the ultimate methane yield from the cattle manure alone. The thermophilic co-digestion on the other hand yielded maximum specific methane, together with the improvement in different process characteristics, as the feeding of algae maximized at the final stage. The trend of methane production from this reactor nevertheless was sharply downward towards the end of the experiment suggesting that the optimum feeding ratio has already been achieved for the present experimental conditions

  9. Biochemical characterization of a thermophilic β-mannanase from Talaromyces leycettanus JCM12802 with high specific activity.

    Science.gov (United States)

    Wang, Caihong; Luo, Huiying; Niu, Canfang; Shi, Pengjun; Huang, Huoqing; Meng, Kun; Bai, Yingguo; Wang, Kun; Hua, Huifang; Yao, Bin

    2015-02-01

    Thermophilic β-mannanases are of increasing importance for wide industrial applications. In the current study, gene cloning, functional expression in Pichia pastoris, and characterization of a thermophilic β-mannanase (Man5A) from thermophilic Talaromyces leycettanus JCM12802 are reported. Deduced Man5A exhibits the highest identity with a putative β-mannanase from Talaromyces stipitatus ATCC10500 (70.3 %) and is composed of an N-terminal signal peptide, a fungal-type carbohydrate-binding module (CBM) of family 1, and a catalytic domain of glycosyl hydrolase (GH) family 5 at the C-terminus. Two recombinant proteins with different glycosylation levels, termed Man5A1 (72 kDa) and Man5A2 (60 kDa), were identified after purification. Both enzymes were thermophilic, exhibiting optimal activity at 85-90 °C, and were highly stable at 70 °C. Man5A1 and Man5A2 had a pH optimum of 4.5 and 4.0, respectively, and were highly stable over the broad pH range of 3.0-10.0. Most metal ions and sodium dodecyl sulfate (SDS) had no effect on the enzymatic activities. Man5A1 and Man5A2 exhibited high specific activity (2,160 and 1,800 U/mg, respectively) when using locust bean gum as the substrate. The CBM1 and two key residues D191 and R286 were found to affect Man5A thermostability. Man5A displays a classical four-site-binding mode, hydrolyzing mannooligosaccharides into smaller units, galactomannan into mannose and mannobiose, and glucomanman into mannose, mannobiose, and mannopentaose, respectively. All these properties make Man5A a good candidate for extensive applications in the bioconversion, pulp bleaching, textile, food, and feed industries.

  10. Bioleaching of chalcopyrite and bornite by moderately thermophilic bacteria: an emphasis on their interactions

    Science.gov (United States)

    Zhao, Hong-bo; Wang, Jun; Gan, Xiao-wen; Qin, Wen-qing; Hu, Ming-hao; Qiu, Guan-zhou

    2015-08-01

    Interactions between chalcopyrite and bornite during bioleaching by moderately thermophilic bacteria were investigated mainly by X-ray diffraction, scanning electron microscopy, and electrochemical measurements performed in conjunction with bioleaching experiments. The results showed that a synergistic effect existed between chalcopyrite and bornite during bioleaching by both Acidithiobacillus caldus and Leptospirillum ferriphilum and that extremely high copper extraction could be achieved when chalcopyrite and bornite coexisted in a bioleaching system. Bornite dissolved preferentially because of its lower corrosion potential, and its dissolution was accelerated by the galvanic current during the initial stage of bioleaching. The galvanic current and optimum redox potential of 390-480 mV vs. Ag/AgCl promoted the reduction of chalcopyrite to chalcocite (Cu2S), thus accelerating its dissolution.

  11. Thermophilic archaeal enzymes and applications in biocatalysis.

    Science.gov (United States)

    Littlechild, Jennifer A

    2011-01-01

    Thermophilic enzymes have advantages for their use in commercial applications and particularly for the production of chiral compounds to produce optically pure pharmaceuticals. They can be used as biocatalysts in the application of 'green chemistry'. The thermophilic archaea contain enzymes that have already been used in commercial applications such as the L-aminoacylase from Thermococcus litoralis for the resolution of amino acids and amino acid analogues. This enzyme differs from bacterial L-aminoacylases and has similarities to carboxypeptidases from other archaeal species. An amidase/γ-lactamase from Sulfolobus solfataricus has been used for the production of optically pure γ-lactam, the building block for antiviral carbocyclic nucleotides. This enzyme has similarities to the bacterial signature amidase family. An alcohol dehydrogenase from Aeropyrum pernix has been used for the production of optically pure alcohols and is related to the zinc-containing eukaryotic alcohol dehydrogenases. A transaminase and a dehalogenase from Sulfolobus species have also been studied. The archaeal transaminase is found in a pathway for serine synthesis which is found only in eukaryotes and not in bacteria. It can be used for the asymmetric synthesis of homochiral amines of high enantioselective purity. The L-2-haloacid dehalogenase has applications both in biocatalysis and in bioremediation. All of these enzymes have increased thermostability over their mesophilic counterparts.

  12. 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

  13. Thermal adaptation of mesophilic and thermophilic FtsZ assembly by modulation of the critical concentration.

    Directory of Open Access Journals (Sweden)

    Luis Concha-Marambio

    Full Text Available Cytokinesis is the last stage in the cell cycle. In prokaryotes, the protein FtsZ guides cell constriction by assembling into a contractile ring-shaped structure termed the Z-ring. Constriction of the Z-ring is driven by the GTPase activity of FtsZ that overcomes the energetic barrier between two protein conformations having different propensities to assemble into polymers. FtsZ is found in psychrophilic, mesophilic and thermophilic organisms thereby functioning at temperatures ranging from subzero to >100°C. To gain insight into the functional adaptations enabling assembly of FtsZ in distinct environmental conditions, we analyzed the energetics of FtsZ function from mesophilic Escherichia coli in comparison with FtsZ from thermophilic Methanocaldococcus jannaschii. Presumably, the assembly may be similarly modulated by temperature for both FtsZ orthologs. The temperature dependence of the first-order rates of nucleotide hydrolysis and of polymer disassembly, indicated an entropy-driven destabilization of the FtsZ-GTP intermediate. This destabilization was true for both mesophilic and thermophilic FtsZ, reflecting a conserved mechanism of disassembly. From the temperature dependence of the critical concentrations for polymerization, we detected a change of opposite sign in the heat capacity, that was partially explained by the specific changes in the solvent-accessible surface area between the free and polymerized states of FtsZ. At the physiological temperature, the assembly of both FtsZ orthologs was found to be driven by a small positive entropy. In contrast, the assembly occurred with a negative enthalpy for mesophilic FtsZ and with a positive enthalpy for thermophilic FtsZ. Notably, the assembly of both FtsZ orthologs is characterized by a critical concentration of similar value (1-2 μM at the environmental temperatures of their host organisms. These findings suggest a simple but robust mechanism of adaptation of FtsZ, previously shown

  14. Xylanase, CM-cellulase and avicelase production by the thermophilic fungus Sporotrichum thermophile

    Energy Technology Data Exchange (ETDEWEB)

    Margaritis, A; Merchant, R; Yaguchi, M

    1983-01-01

    When wheat straw was used as C source, S. thermophile produced large amounts of xylanase extracellularly in addition to CM-cellulase and Avicelase. These enzymes were isolated by alcohol precipitation, desalting, and column chromatography. The molecular weights were estimated to be 25,0065,000 and 84,000 for xylanase, CM-cellulase, and Avicelase, respectively. Serine and threonine were the most abundant amino acids and these enzymes are very acidic proteins.

  15. Optimum Thermal Processing for Extended Shelf-Life (ESL) Milk.

    Science.gov (United States)

    Deeth, Hilton

    2017-11-20

    Extended shelf-life (ESL) or ultra-pasteurized milk is produced by thermal processing using conditions between those used for traditional high-temperature, short-time (HTST) pasteurization and those used for ultra-high-temperature (UHT) sterilization. It should have a refrigerated shelf-life of more than 30 days. To achieve this, the thermal processing has to be quite intense. The challenge is to produce a product that has high bacteriological quality and safety but also very good organoleptic characteristics. Hence the two major aims in producing ESL milk are to inactivate all vegetative bacteria and spores of psychrotrophic bacteria, and to cause minimal chemical change that can result in cooked flavor development. The first aim is focused on inactivation of spores of psychrotrophic bacteria, especially Bacillus cereus because some strains of this organism are pathogenic, some can grow at ≤7 °C and cause spoilage of milk, and the spores of some strains are very heat-resistant. The second aim is minimizing denaturation of β-lactoglobulin (β-Lg) as the extent of denaturation is strongly correlated with the production of volatile sulfur compounds that cause cooked flavor. It is proposed that the heating should have a bactericidal effect, B * (inactivation of thermophilic spores), of >0.3 and cause ≤50% denaturation of β-Lg. This can be best achieved by heating at high temperature for a short holding time using direct heating, and aseptically packaging the product.

  16. Optimum Thermal Processing for Extended Shelf-Life (ESL Milk

    Directory of Open Access Journals (Sweden)

    Hilton Deeth

    2017-11-01

    Full Text Available Extended shelf-life (ESL or ultra-pasteurized milk is produced by thermal processing using conditions between those used for traditional high-temperature, short-time (HTST pasteurization and those used for ultra-high-temperature (UHT sterilization. It should have a refrigerated shelf-life of more than 30 days. To achieve this, the thermal processing has to be quite intense. The challenge is to produce a product that has high bacteriological quality and safety but also very good organoleptic characteristics. Hence the two major aims in producing ESL milk are to inactivate all vegetative bacteria and spores of psychrotrophic bacteria, and to cause minimal chemical change that can result in cooked flavor development. The first aim is focused on inactivation of spores of psychrotrophic bacteria, especially Bacillus cereus because some strains of this organism are pathogenic, some can grow at ≤7 °C and cause spoilage of milk, and the spores of some strains are very heat-resistant. The second aim is minimizing denaturation of β-lactoglobulin (β-Lg as the extent of denaturation is strongly correlated with the production of volatile sulfur compounds that cause cooked flavor. It is proposed that the heating should have a bactericidal effect, B* (inactivation of thermophilic spores, of >0.3 and cause ≤50% denaturation of β-Lg. This can be best achieved by heating at high temperature for a short holding time using direct heating, and aseptically packaging the product.

  17. Diversity of thermophilic archaeal isolates from hot springs in Japan

    Science.gov (United States)

    Itoh, Takashi; Yoshikawa, Naoto; Takashina, Tomonori

    2005-09-01

    In the light of the significance of extremophiles as model organisms to access possible extraterrestiral life, we provide a short review of the systematics of thermophilic Archaea, and introduce our exploratory research of novel thermophilic Archaea from hot springs in Japan. Up to date, we have isolated 162 strains of the thermophilic Archaea from hot springs in Japan by the enrichment method or the most probable number/PCR method, and the 16S rRNA gene sequences were determined to reveal their phylogenetic diversity. The sequence comparison illustrated that the isolates belonged to the orders Sulfolobales (117 isolates) , Thermoproteales (29 isolates), Desulfurococcales (8 isolates) and Thermoplasmatales (8 isolates), and there were six separate lineages representing new genera, and at least seven new species as predicted by the phylogenetic distance to known species. The collection of isolates not only included novel taxa but would give some implication for a necessity to reevaluate the current taxonomy of the thermophilic Archaea.

  18. Modeling the fate of antibiotic resistance genes and class 1 integrons during thermophilic anaerobic digestion of municipal wastewater solids.

    Science.gov (United States)

    Burch, Tucker R; Sadowsky, Michael J; LaPara, Timothy M

    2015-10-19

    This study investigated the use of thermophilic anaerobic digestion for removing antibiotic resistance genes (ARGs) from residual municipal wastewater solids. Four laboratory-scale anaerobic digesters were operated in 8-day batch cycles at temperatures of 40, 56, 60, and 63 °C. Two tetracycline resistance genes (tet(W) and tet(X)), a fluoroquinolone resistance gene (qnrA), the integrase gene of class 1 integrons (intI1), 16S rRNA genes of all Bacteria, and 16S rRNA genes of methanogens were quantified using real-time quantitative PCR. ARG and intI1 quantities decreased at all temperatures and were described well by a modified form of the Collins-Selleck disinfection kinetic model. The magnitudes of Collins-Selleck kinetic parameters were significantly greater at thermophilic temperatures compared to 40 °C, but few statistically significant differences were observed among these parameters for the thermophilic anaerobic digesters. This model allows for the direct comparison of different operating conditions (e.g., temperature) on anaerobic digestion performance in mitigating the quantity of ARGs in wastewater solids and could be used to design full-scale anaerobic digesters to specifically treat for ARGs as a "pollutant" of concern.

  19. CT4 - Cost-Optimum Procedures

    DEFF Research Database (Denmark)

    Thomsen, Kirsten Engelund; Wittchen, Kim Bjarne

    This report collects the status in European member states regarding implementation of the cos optimum procedure for setting energy performance requirements to new and existing buildings.......This report collects the status in European member states regarding implementation of the cos optimum procedure for setting energy performance requirements to new and existing buildings....

  20. Investigation of the thermophilic mechanism in the genus Porphyrobacter by comparative genomic analysis.

    Science.gov (United States)

    Xu, Lin; Wu, Yue-Hong; Zhou, Peng; Cheng, Hong; Liu, Qian; Xu, Xue-Wei

    2018-05-23

    Type strains of the genus Porphyrobacter belonging to the family Erythrobacteraceae and the class Alphaproteobacteria have been isolated from various environments, such as swimming pools, lake water and hot springs. P. cryptus DSM 12079 T and P. tepidarius DSM 10594 T out of all Erythrobacteraceae type strains, are two type strains that have been isolated from geothermal environments. Next-generation sequencing (NGS) technology offers a convenient approach for detecting situational types based on protein sequence differences between thermophiles and mesophiles; amino acid substitutions can lead to protein structural changes, improving the thermal stabilities of proteins. Comparative genomic studies have revealed that different thermal types exist in different taxa, and few studies have been focused on the class Alphaproteobacteria, especially the family Erythrobacteraceae. In this study, eight genomes of Porphyrobacter strains were compared to elucidate how Porphyrobacter thermophiles developed mechanisms to adapt to thermal environments. P. cryptus DSM 12079 T grew optimally at 50 °C, which was higher than the optimal growth temperature of other Porphyrobacter type strains. Phylogenomic analysis of the genus Porphyrobacter revealed that P. cryptus DSM 12079 T formed a distinct and independent clade. Comparative genomic studies uncovered that 1405 single-copy genes were shared by Porphyrobacter type strains. Alignments of single-copy proteins showed that various types of amino acid substitutions existed between P. cryptus DSM 12079 T and the other Porphyrobacter strains. The primary substitution types were changes from glycine/serine to alanine. P. cryptus DSM 12079 T was the sole thermophile within the genus Porphyrobacter. Phylogenomic analysis and amino acid frequencies indicated that amino acid substitutions might play an important role in the thermophily of P. cryptus DSM 12079 T . Bioinformatic analysis revealed that major amino acid substitutional types

  1. Mesophilic and thermophilic anaerobic digestion of sulphate-containing wastewaters.

    Science.gov (United States)

    Colleran, E; Pender, S

    2002-01-01

    The effect of sulphate at an influent chemical oxygen demand (COD):sulphate ratio of 4 on the operational performance of anaerobic hybrid reactors treating molasses wastewater was investigated under mesophilic and thermophilic conditions in a long-term laboratory-scale study over a 1,081 day period. The presence of sulphate reduced the COD removal efficiency under both mesophilic and thermophilic conditions. At 55 degrees C, effluent acetate levels were consistently greater than 4000 mg l(-1) indicating that thermophilic acetate-utilising methane-producing bacteria (MPB) or sulphate-reducing bacteria (SRB) had not developed in the reactor under the conditions applied. At 37 degrees C, acetate was exclusively utilised by acetoclastic methanogens, whereas H2-utilising SRB predominated over H2-utilising MPB in the competition for hydrogen. By contrast, hydrogenotrophic MPB were shown to outcompete H2-utilising SRB during long-term thermophilic operation. 16SrDNA analysis of the seed sludge and reactor biomass on conclusion of the 37 degrees C and 55 degrees C trials illustrated that the dominant methanogen present on conclusion of the thermophilic trial in the absence of influent sulphate was related to Methanocorpusculum parvuum, and was capable of growth on both acetate and hydrogen. By contrast, an organism closely related to Methanobacterium thermoautotrophicum was the dominant methanogen present in the sulphate-fed reactor on completion of the thermophilic trial.

  2. The formation of illite from nontronite by mesophilic and thermophilic bacterial reaction

    Science.gov (United States)

    Jaisi, Deb P.; Eberl, Dennis D.; Dong, Hailiang; Kim, Jinwook

    2011-01-01

    The formation of illite through the smectite-to-illite (S-I) reaction is considered to be one of the most important mineral reactions occurring during diagenesis. In biologically catalyzed systems, however, this transformation has been suggested to be rapid and to bypass the high temperature and long time requirements. To understand the factors that promote the S-I reaction, the present study focused on the effects of pH, temperature, solution chemistry, and aging on the S-I reaction in microbially mediated systems. Fe(III)-reduction experiments were performed in both growth and non-growth media with two types of bacteria: mesophilic (Shewanella putrefaciens CN32) and thermophilic (Thermus scotoductus SA-01). Reductive dissolution of NAu-2 was observed and the formation of illite in treatment with thermophilic SA-01 was indicated by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). A basic pH (8.4) and high temperature (65°C) were the most favorable conditions for the formation of illite. A long incubation time was also found to enhance the formation of illite. K-nontronite (non-permanent fixation of K) was also detected and differentiated from the discrete illite in the XRD profiles. These results collectively suggested that the formation of illite associated with the biologically catalyzed smectite-to-illite reaction pathway may bypass the prolonged time and high temperature required for the S-I reaction in the absence of microbial activity.

  3. Draft Genome Sequence of Aeribacillus pallidus Strain 8m3, a Thermophilic Hydrocarbon-Oxidizing Bacterium Isolated from the Dagang Oil Field (China).

    Science.gov (United States)

    Poltaraus, Andrey B; Sokolova, Diyana S; Grouzdev, Denis S; Ivanov, Timophey M; Malakho, Sophia G; Korshunova, Alena V; Rozanov, Aleksey S; Tourova, Tatiyana P; Nazina, Tamara N

    2016-06-09

    The draft genome sequence of Aeribacillus pallidus strain 8m3, a thermophilic aerobic oil-oxidizing bacterium isolated from production water from the Dagang high-temperature oil field, China, is presented here. The genome is annotated to provide insights into the genomic and phenotypic diversity of the genus Aeribacillus. Copyright © 2016 Poltaraus et al.

  4. Draft Genome Sequence of Aeribacillus pallidus Strain 8m3, a Thermophilic Hydrocarbon-Oxidizing Bacterium Isolated from the Dagang Oil Field (China)

    OpenAIRE

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

    2016-01-01

    The draft genome sequence of Aeribacillus pallidus strain 8m3, a thermophilic aerobic oil-oxidizing bacterium isolated from production water from the Dagang high-temperature oil field, China, is presented here. The genome is annotated to provide insights into the genomic and phenotypic diversity of the genus Aeribacillus.

  5. Deep Conversion of Carbon Monoxide to Hydrogen and Formation of Acetate by the Anaerobic Thermophile Carboxydothermus hydrogenoformans

    OpenAIRE

    Henstra, Anne M.; Stams, Alfons 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 catalytic processes, makes this organism an interesting alternative for production of cheap hydrogen gas suitable to fuel CO-sensitive fuel cells in a future hydrogen economy, provided sufficiently lo...

  6. Comparative study on the selective chalcopyrite bioleaching of a molybdenite concentrate with mesophilic and thermophilic bacteria.

    Science.gov (United States)

    Romano, P; Blázquez, M L; Alguacil, F J; Muñoz, J A; Ballester, A; González, F

    2001-03-01

    This study evaluates different bioleaching treatments of a molybdenite concentrate using mesophilic and thermophilic bacterial cultures. Further studies on the chemical leaching and the electrochemical behavior of the MoS(2) concentrate were carried out. Bioleaching tests showed a progressive removal of chalcopyrite from the molybdenite concentrate with an increase in temperature. Chemical leaching tests support the idea of an indirect attack of the concentrate. Electrochemical tests indicate that chalcopyrite dissolution is favored when molybdenite is present. Therefore, this type of bioleaching treatment could be applied to purify molybdenite flotation concentrates by selectively dissolving chalcopyrite.

  7. Xylanases of thermophilic bacteria from Icelandic hot springs

    Energy Technology Data Exchange (ETDEWEB)

    Pertulla, M; Raettoe, M; Viikari, L [VTT, Biotechnical Lab., Espoo (Finland); Kondradsdottir, M [Dept. of Biotechnology, Technological Inst. of Iceland, Reykjavik (Iceland); Kristjansson, J K [Dept. of Biotechnology, Technological Inst. of Iceland, Reykjavik (Iceland) Inst. of Biotechnology, Iceland Univ., Reykjavik (Iceland)

    1993-02-01

    Thermophilic, aerobic bacteria isolated from Icelandic hot springs were screened for xylanase activity. Of 97 strains tested, 14 were found to be xylanase positive. Xylanase activities up to 12 nkat/ml were produced by these strains in shake flasks on xylan medium. The xylanases of the two strains producing the highest activities (ITI 36 and ITI 283) were similar with respect to temperature and pH optima (80deg C and pH 8.0). Xylanase production of strain ITI 36 was found to be induced by xylan and xylose. Xylanase activity of 24 nkat/ml was obtained with this strain in a laboratory-scale-fermentor cultivation on xylose medium. [beta]-Xylosidase activity was also detected in the culture filtrate. The thermal half-life of ITI 36 xylanase was 24 h at 70deg C. The highest production of sugars from hydrolysis of beech xylan was obtained at 70deg C, although xylan depolymerization was detected even up to 90deg C. (orig.).

  8. 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.

  9. PRODUCTION AND CHARACTERIZATION OF AN ALKALOTHERMOSTABLE, ORGANIC SOLVENT TOLERANT AND SURFACTANT TOLERANT ESTERASE PRODUCED BY A THERMOPHILIC BACTERIUM GEOBACILLUS SP. AGP-04, ISOLATED FROM BAKRESHWAR HOT SPRING, INDIA

    Directory of Open Access Journals (Sweden)

    Amit Ghati

    2013-10-01

    Full Text Available A thermophilic bacteria, Geobacillus sp. AGP-04, isolated from Surya Kund hot spring, Bakreshwar, West Bengal, India was studied in terms of capability of tributyrin hydrolysis and characterization of its thermostable esterase activity using p-nitrophenyl butyrate (PNPB as substrate. The extracellular crude preparation was characterized in terms of pH and temperature optima and stability, organic solvent tolerance capacity and stability, substrate specificity, surfactant tolerance capacity, kinetic parameters and activation/inhibition behavior towards some metal ions and chemicals. Tributyrin agar assay exhibited that Geobacillus sp. AGP-04 secretes an extracellular esterase. The Vmax and Km values of the esterase were found to be 5099 U/Land 103.5µM, respectively in the presence of PNPB as substrate. The optimum temperature and pH, for Geobacillus sp. AGP-04 esterase was 60oC and 8.0, respectively. Although the enzyme activity was not significantly altered by incubating crude extract solution at 20-70oC for 1 hour, the enzyme activity was fully lost at 90oC for same incubation period. The pH stability profile showed that original crude esterase activity is stable at a broad range (pH 5.0-10.0. Moreover, the enzyme was highly organic solvent and surfactant tolerant. The effect of some chemical on crude esterase activity indicated that Geobacillus sp. AGP-04 produce an esterase which contains a serine residue in active site and for its activity -SH groups are essential. Besides, enzyme production was highly induced if fermentation medium contain polysaccharides and oil as carbon source.

  10. Bioprocess for the production of recombinant HAP phytase of the thermophilic mold Sporotrichum thermophile and its structural and biochemical characteristics.

    Science.gov (United States)

    Maurya, Anay Kumar; Parashar, Deepak; Satyanarayana, T

    2017-01-01

    Thermophilc mold Sporotrichum thermophile secretes an acidstable and thermostable phytase, which finds application as a food and feed additive because of its adequate thermostability, acid stability, protease insensitivity and broad substrate spectrum. Low extracellular phytase production by the mold is a major bottleneck for its application on a commercial scale. We have successfully overcome this problem by constitutive secretary expression of codon optimized rStPhy under glyceraldehyde phosphate dehydrogenase (GAP) promoter in Pichia pastoris. A ∼41-fold improvement in rStPhy production has been achieved. Circular Dichroism (CD) spectra revealed that rStPhy is composed of 26.65% α-helices, 5.26% β-sheets and 68.09% random coils at pH 5.0 and 60°C, the optima for the enzyme activity. The melting temperature (T m ) of the enzyme is ∼73°C. The 3D structure of rStPhy displayed characteristic signature sequences (RHGXRXP and HD) of HAP phytase. The catalytically important amino acids (Arg74, His75, Arg78, His368 and Asp369) were identified by docking and site directed mutagenesis. Fluorescence quenching by N-bromosuccinimide (NBS) and CsCl exposed tryptophan residues surrounded by negative charges, which play a key role in maintaining structural integrity of rStPhy. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Temporal change of composition and potential activity of the thermophilic archaeal community during the composting of organic material.

    Science.gov (United States)

    Thummes, Kathrin; Kämpfer, Peter; Jäckel, Udo

    2007-07-01

    To date, composting has been regarded as an aerobic process but it has been shown that composting piles are often sources of atmospheric methane. In order to gain a more comprehensive view on the diversity of methanogenic Archaea in compost, gas chromatographical methods and molecular cloning were used to study relationships of thermophilic archaeal communities and changes in methane production potential during compost maturation. According to the thermophilic methane production potential, wide differences could be detected between differently aged compost materials. In material derived from 3- and 4-week-old piles, low and no thermophilic methane production potential, respectively, was observed at 50 degrees C. Material from a 6-week-old pile showed the maximum methane production. With compost maturation, the production slowly decreased again with 6 weeks, 8 weeks, and mature compost showing an optimum methane production potential at 60 degrees C. At 70 degrees C, only 6-week-old material showed a comparable high production of methane. The 16S rRNA-based phylogenetic surveys revealed an increase of archaeal diversity with compost maturation. In the 6-week-old material, 86% of the sequences in the archaeal 16S rRNA library had the highest sequence similarities to Methanothermobacter spp. and the remaining 14% of the clones were related to Methanosarcina thermophila. Quantification of methanogens in 6-week-old material, on the basis of the methane production rate, resulted in values of about 2x10(7) cells per gram fresh weight. In 8-week-old and mature compost material, the proportion of sequences similar to Methanothermobacter spp. decreased to 34% and 0%, respectively. The mature compost material showed the highest variation in identified sequences, although 33% could be assigned to as yet uncultured Archaea (e.g. Rice cluster I, III, and IV). Our results indicate that compost harbours a diverse community of thermophilic methanogens, with changing composition

  12. Thermophilic versus Mesophilic Anaerobic Digestion of Sewage Sludge: A Comparative Review

    Science.gov (United States)

    Gebreeyessus, Getachew D.; Jenicek, Pavel

    2016-01-01

    During advanced biological wastewater treatment, a huge amount of sludge is produced as a by-product of the treatment process. Hence, reuse and recovery of resources and energy from the sludge is a big technological challenge. The processing of sludge produced by Wastewater Treatment Plants (WWTPs) is massive, which takes up a big part of the overall operational costs. In this regard, anaerobic digestion (AD) of sewage sludge continues to be an attractive option to produce biogas that could contribute to the wastewater management cost reduction and foster the sustainability of those WWTPs. At the same time, AD reduces sludge amounts and that again contributes to the reduction of the sludge disposal costs. However, sludge volume minimization remains, a challenge thus improvement of dewatering efficiency is an inevitable part of WWTP operation. As a result, AD parameters could have significant impact on sludge properties. One of the most important operational parameters influencing the AD process is temperature. Consequently, the thermophilic and the mesophilic modes of sludge AD are compared for their pros and cons by many researchers. However, most comparisons are more focused on biogas yield, process speed and stability. Regarding the biogas yield, thermophilic sludge AD is preferred over the mesophilic one because of its faster biochemical reaction rate. Equally important but not studied sufficiently until now was the influence of temperature on the digestate quality, which is expressed mainly by the sludge dewateringability, and the reject water quality (chemical oxygen demand, ammonia nitrogen, and pH). In the field of comparison of thermophilic and mesophilic digestion process, few and often inconclusive research, unfortunately, has been published so far. Hence, recommendations for optimized technologies have not yet been done. The review presented provides a comparison of existing sludge AD technologies and the gaps that need to be filled so as to optimize

  13. Morphological and phylogenetic diversity of thermophilic cyanobacteria in Algerian hot springs.

    Science.gov (United States)

    Amarouche-Yala, Samia; Benouadah, Ali; El Ouahab Bentabet, Abd; López-García, Purificación

    2014-11-01

    Geothermal springs in Algeria have been known since the Roman Empire. They mainly locate in Eastern Algeria and are inhabited by thermophilic organisms, which include cyanobacteria forming mats and concretions. In this work, we have investigated the cyanobacterial diversity of these springs. Cyanobacteria were collected from water, concretions and mats in nine hot springs with water temperatures ranging from 39 to 93 °C. Samples were collected for isolation in culture, microscopic morphological examination, and molecular diversity analysis based on 16S rRNA gene sequences. Nineteen different cyanobacterial morphotypes were identified, the most abundant of which were three species of Leptolyngbya, accompanied by members of the genera Gloeocapsa, Gloeocapsopsis, Stigonema, Fischerella, Synechocystis, Microcoleus, Cyanobacterium, Chroococcus and Geitlerinema. Molecular diversity analyses were in good general agreement with classical identification and allowed the detection of additional species in three springs with temperatures higher than 50 °C. They corresponded to a Synechococcus clade and to relatives of the intracellularly calcifying Candidatus Gloeomargarita lithophora. The hottest springs were dominated by members of Leptolyngbya, Synechococcus-like cyanobacteria and Gloeomargarita, whereas Oscillatoriales other than Leptolyngbya, Chroococcales and Stigonematales dominated lower temperature springs. The isolation of some of these strains sets the ground for future studies on the biology of thermophilic cyanobacteria.

  14. Ion permeability of the cytoplasmic membrane limits the maximum growth temperature of bacteria and archaea

    NARCIS (Netherlands)

    van de Vossenberg, J.L C M; Ubbink-Kok, T.; Elferink, M.G.L.; Driessen, A.J.M.; Konings, W.N

    1995-01-01

    Protons and sodium ions are the most commonly used coupling ions in energy transduction in bacteria and archaea. At their growth temperature, the permeability of the cytoplasmic membrane of thermophilic bacteria to protons is high compared with that of sodium ions. In some thermophiles, sodium is

  15. Effect of temperature and hydraulic retention time on hydrogen producing granules: Homoacetogenesis and morphological characteristics

    International Nuclear Information System (INIS)

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

    2009-01-01

    The effect of temperature and hydraulic retention time (HRT) on the homoacetogenesisi and on the morphological characteristics of hydrogen producing granules was investigated. Hydrogen was produced using an expanded granular sludge blanket (EGSB) reactor, fed with glucose and L-arabinose, under mesophilic (37 degree centigrade), thermophilic (55 degree centigrade), and hyper thermophilic (70 degree centigrade) conditions. (Author)

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

    Science.gov (United States)

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

    2008-12-01

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

  17. On Optimum Safety Levels of Breakwaters

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Sørensen, John Dalsgaard

    2006-01-01

    The paper presents results from numerical simulations performed with the objective of identifying optimum design safety levels of conventional rubble mound and caisson breakwaters, corresponding to the lowest costs over the service life of the structures. The work is related to the PIANC Working...... Group 47 on "Selection of type of breakwater structures". The paper summaries results given in Burcharth and Sorensen (2005) related to outer rubble mound breakwaters but focus on optimum safety levels for outer caisson breakwaters on low and high rubble foundations placed on sea beds strong enough...... to resist geotechnical slip failures. Optimum safety levels formulated for use both in deterministic and probabilistic design procedures are given. Results obtained so far indicate that the optimum safety levels for caisson breakwaters are much higher than for rubble mound breakwaters....

  18. Optimum Stratification of a Skewed Population

    OpenAIRE

    D.K. Rao; M.G.M. Khan; K.G. Reddy

    2014-01-01

    The focus of this paper is to develop a technique of solving a combined problem of determining Optimum Strata Boundaries(OSB) and Optimum Sample Size (OSS) of each stratum, when the population understudy isskewed and the study variable has a Pareto frequency distribution. The problem of determining the OSB isformulated as a Mathematical Programming Problem (MPP) which is then solved by dynamic programming technique. A numerical example is presented to illustrate the compu...

  19. Fractionation of carbon isotopes by thermophilic methanogenic bacteria

    International Nuclear Information System (INIS)

    Ivanov, M.V.; Belyaev, S.S.; Zyakun, A.M.; Bondar, V.A.; Shipin, O.P.; Laurinavichus, K.S.

    1985-01-01

    The authors investigated the pattern of fractionation of stable carbon isotopes by the thermophilic methane-forming bacteria under different growth conditions and at various rates of formation of methane. A pure culture of Methanobacterium thermoautotrophicum was used in the experiments under the following growth conditions: temperature 65-70 0 C; pH 7.2-7.6; NaCl content 0-0.9 g/liter. The methanogenic bacteria were cultivated in 0.15 liter flasks in mineral medium. A mixture of CO 2 and H 2 in a 1:4 ratio by volume served as the sole carbon and energy source. In all experiments, not more than 5% of the initial CO 2 level was utilized. The rate of methane generation was altered by adjusting the physicochemical growth parameters (temperature from 45-70 0 C, salinity from 0.9 to 40 g/liter NaCl, pH from 6.3 to 7.2). Methane in the samples was quantitatively determined in a chromatograph which had a flame-ionization detector and a column containing Porapak Q sorbent at T = 120 0 C. The carrier gas was CO 2 . The average specific rate of methane formation was calculated as ml CH 4 per mg dry biomass of bacteria per h. Soluble mineral carbon was isolated form the acidified culture liquid in the form of CO 2 and was quantitatively determined in a Chrom-4 chromatography provided with a katharometer and a column containing activated charcoal at T = 150 0 . The gas carrier was helium. The isotopic composition of carbon was determined in a CH-7 mass-spectrometer and was expressed in 13 C values (per thousand) with respect to the international PDB standard

  20. Cellulolytic and xylanolytic enzymes from thermophilic Aspergillus terreus RWY.

    Science.gov (United States)

    Sharma, Reetika; Kocher, Gurvinder Singh; Bhogal, Ravinder Singh; Oberoi, Harinder Singh

    2014-12-01

    Thermophilic Aspergillus terreus RWY produced cellulases and xylanases in optimal concentrations at 45 °C in solid state fermentation process, though enzyme production was also observed at 50 and 55 °C. Filter paper cellulase (FP), endoglucanase (EG), β-glucosidase (BGL), cellobiohydrolase (CBH), xylanase, β-xylosidase, α-L-arabinofuranosidase and xylan esterase activities for A. terreus RWY at 45 °C in 72 h were 11.3 ± 0.65, 103 ± 6.4, 122.5 ± 8.7, 10.3 ± 0.66, 872 ± 22.5, 22.1 ± 0.75, 126.4 ± 8.4 and 907 ± 15.5 U (g-ds)(-1) , respectively. Enzyme was optimally active at temperatures and pH ranging between 50-60 °C and 4.0-6.0, respectively. The half life (T1/2 ) of 270 and 240 min at 70 and 75 °C, respectively for the enzyme indicates its stability at higher temperatures. The addition of MnCl2 , CoCl2 , and FeCl3 significantly enhanced cellulase activity. Enzyme demonstrated multiplicity by having seven, one and three isoform(s) for EG, CBH and BGL, respectively. Significant production of functionally active consortium of cellulolytic and xylanolytic enzymes from A. terreus RWY makes it a potential candidate in bioprocessing applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Effect of feed to microbe ratios on anaerobic digestion of Chinese cabbage waste under mesophilic and thermophilic conditions: biogas potential and kinetic study.

    Science.gov (United States)

    Kafle, Gopi Krishna; Bhattarai, Sujala; Kim, Sang Hun; Chen, Lide

    2014-01-15

    The objective of this study was to investigate the effect of the feed-to-microbe (F/M) ratios on anaerobic digestion of Chinese cabbage waste (CCW) generated from a kimchi factory. The batch test was conducted for 96 days under mesophilic (36.5 °C) (Experiment I) and thermophilic (55 °C) conditions (Experiment II) at F/M ratios of 0.5, 1.0 and 2.0. The first-order kinetic model was evaluated for methane yield. The biogas yield in terms of volatile solids (VS) added increased from 591 to 677 mL/g VS under mesophilic conditions and 434 to 639 mL/g VS under thermophilic conditions when the F/M ratio increased from 0.5 to 2.0. Similarly, the volumetric biogas production increased from 1.479 to 6.771 L/L under mesophilic conditions and from 1.086 to 6.384 L/L under thermophilic conditions when F/M ratio increased from 0.5 to 2.0. The VS removal increased from 59.4 to 75.6% under mesophilic conditions and from 63.5 to 78.3% under thermophilic conditions when the F/M ratio increased from 0.5 to 2.0. The first-order kinetic constant (k, 1/day) decreased under the mesophilic temperature conditions and increased under thermophilic conditions when the F/M ratio increased from 0.5 to 2.0. The difference between the experimental and predicted methane yield was in the range of 3.4-14.5% under mesophilic conditions and in the range of 1.1-3.0% under thermophilic conditions. The predicted methane yield derived from the first-order kinetic model was in good agreement with the experimental results. Published by Elsevier Ltd.

  2. Diversity of thermophiles in a Malaysian hot spring determined using 16S rRNA and shotgun metagenome sequencing.

    Science.gov (United States)

    Chan, Chia Sing; Chan, Kok-Gan; Tay, Yea-Ling; Chua, Yi-Heng; Goh, Kian Mau

    2015-01-01

    The Sungai Klah (SK) hot spring is the second hottest geothermal spring in Malaysia. This hot spring is a shallow, 150-m-long, fast-flowing stream, with temperatures varying from 50 to 110°C and a pH range of 7.0-9.0. Hidden within a wooded area, the SK hot spring is continually fed by plant litter, resulting in a relatively high degree of total organic content (TOC). In this study, a sample taken from the middle of the stream was analyzed at the 16S rRNA V3-V4 region by amplicon metagenome sequencing. Over 35 phyla were detected by analyzing the 16S rRNA data. Firmicutes and Proteobacteria represented approximately 57% of the microbiome. Approximately 70% of the detected thermophiles were strict anaerobes; however, Hydrogenobacter spp., obligate chemolithotrophic thermophiles, represented one of the major taxa. Several thermophilic photosynthetic microorganisms and acidothermophiles were also detected. Most of the phyla identified by 16S rRNA were also found using the shotgun metagenome approaches. The carbon, sulfur, and nitrogen metabolism within the SK hot spring community were evaluated by shotgun metagenome sequencing, and the data revealed diversity in terms of metabolic activity and dynamics. This hot spring has a rich diversified phylogenetic community partly due to its natural environment (plant litter, high TOC, and a shallow stream) and geochemical parameters (broad temperature and pH range). It is speculated that symbiotic relationships occur between the members of the community.

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

    Science.gov (United States)

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

    2006-10-01

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

  4. Conductive iron oxides accelerate thermophilic methanogenesis from acetate and propionate.

    Science.gov (United States)

    Yamada, Chihaya; Kato, Souichiro; Ueno, Yoshiyuki; Ishii, Masaharu; Igarashi, Yasuo

    2015-06-01

    Anaerobic digester is one of the attractive technologies for treatment of organic wastes and wastewater, while continuous development and improvements on their stable operation with efficient organic removal are required. Particles of conductive iron oxides (e.g., magnetite) are known to facilitate microbial interspecies electron transfer (termed as electric syntrophy). Electric syntrophy has been reported to enhance methanogenic degradation of organic acids by mesophilic communities in soil and anaerobic digester. Here we investigated the effects of supplementation of conductive iron oxides (magnetite) on thermophilic methanogenic microbial communities derived from a thermophilic anaerobic digester. Supplementation of magnetite accelerated methanogenesis from acetate and propionate under thermophilic conditions, while supplementation of ferrihydrite also accelerated methanogenesis from propionate. Microbial community analysis revealed that supplementation of magnetite drastically changed bacterial populations in the methanogenic acetate-degrading cultures, in which Tepidoanaerobacter sp. and Coprothermobacter sp. dominated. These results suggest that supplementation of magnetite induce electric syntrophy between organic acid-oxidizing bacteria and methanogenic archaea and accelerate methanogenesis even under thermophilic conditions. Findings from this study would provide a possibility for the achievement of stably operating thermophilic anaerobic digestion systems with high efficiency for removal of organics and generation of CH4. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  5. Optimum heat power cycles for specified boundary conditions

    International Nuclear Information System (INIS)

    Ibrahim, O.M.; Klein, S.A.; Mitchell, J.W.

    1991-01-01

    In this paper optimization of the power output of Carnot and closed Brayton cycles is considered for both finite and infinite thermal capacitance rates of the external fluid streams. The method of Lagrange multipliers is used to solve for working fluid temperatures that yield maximum power. Analytical expressions for the maximum power and the cycle efficiency at maximum power are obtained. A comparison of the maximum power from the two cycles for the same boundary conditions, i.e., the same heat source/sink inlet temperatures, thermal capacitance rates, and heat exchanger conductances, shows that the Brayton cycle can produce more power than the Carnot cycle. This comparison illustrates that cycles exist that can produce more power than the Carnot cycle. The optimum heat power cycle, which will provide the upper limit of power obtained from any thermodynamic cycle for specified boundary conditions and heat exchanger conductances is considered. The optimum heat power cycle is identified by optimizing the sum of the power output from a sequence of Carnot cycles. The shape of the optimum heat power cycle, the power output, and corresponding efficiency are presented. The efficiency at maximum power of all cycles investigated in this study is found to be equal to (or well approximated by) η = 1 - sq. root T L.in /φT H.in where φ is a factor relating the entropy changes during heat rejection and heat addition

  6. Acquired thermotolerance and heat shock in the extremely thermophilic archaebacterium Sulfolobus sp. strain B12.

    Science.gov (United States)

    Trent, J D; Osipiuk, J; Pinkau, T

    1990-03-01

    The extreme thermophile Sulfolobus sp. strain B12 exhibits an acquired thermotolerance response. Thus, survival of cells from a 70 degrees C culture at the lethal temperature of 92 degrees C was enhanced by as much as 6 orders of magnitude over a 2-h period if the culture was preheated to 88 degrees C for 60 min or longer before being exposed to the lethal temperature. In eubacteria and eucaryotes, acquired thermotolerance correlates with the induced synthesis of a dozen or so proteins known as heat shock proteins. In this Sulfolobus species, it correlates with the preferential synthesis of primarily one major protein (55 kilodaltons) and, to a much lesser extent, two minor proteins (28 and 35 kilodaltons). Since the synthesis of all other proteins was radically reduced and these proteins were apparently not degraded or exported, their relative abundance within the cell increased during the time the cells were becoming thermotolerant. They could not yet be related to known heat shock proteins. In immunoassays, they were not cross-reactive with antibodies against heat shock proteins from Escherichia coli (DnaK and GroE), which are highly conserved between eubacteria and eucaryotes. However, it appears that if acquired thermotolerance depends on the synthesis of protective proteins, then in this extremely thermophilic archaebacterium it depends primarily on one protein.

  7. Protease Production by Different Thermophilic Fungi

    Science.gov (United States)

    Macchione, Mariana M.; Merheb, Carolina W.; Gomes, Eleni; da Silva, Roberto

    A comparative study was carried out to evaluate protease production in solid-state fermentation (SSF) and submerged fermentation (SmF) by nine different thermophilic fungi — Thermoascus aurantiacus Miehe, Thermomyces lanuginosus, T. lanuginosus TO.03, Aspergillus flavus 1.2, Aspergillus sp. 13.33, Aspergillus sp. 13.34, Aspergillus sp. 13.35, Rhizomucor pusillus 13.36 and Rhizomucor sp. 13.37 — using substrates containing proteins to induce enzyme secretion. Soybean extract (soybean milk), soybean flour, milk powder, rice, and wheat bran were tested. The most satisfactory results were obtained when using wheat bran in SSF. The fungi that stood out in SSF were T. lanuginosus, T. lanuginosus TO.03, Aspergillus sp. 13.34, Aspergillus sp. 13.35, and Rhizomucor sp. 13.37, and those in SmF were T. aurantiacus, T. lanuginosus TO.03, and 13.37. In both fermentation systems, A. flavus 1.2 and R. pusillus 13.36 presented the lowest levels of proteolytic activity.

  8. Methane Emission from Digestion of Palm Oil Mill Effluent (POME in a Thermophilic Anaerobic Reactor

    Directory of Open Access Journals (Sweden)

    I Irvan

    2012-04-01

    Full Text Available As the issue of global warming draws increasing concern, many studies to reduce CO2 and CH4 gases (greenhouse gases, GHG have been implemented in several countries, including in Indonesia. Considering that Indonesia has a huge numbers of palm oil mills, no doubt if their waste water treatment as one of the major sources in GHG.  This paper presents the results from a research project between Metawater Co., Ltd.-Japan and University of Sumatera Utara-Indonesia. The objective of the research is to study the methane emission of thermophilic fermentation in the treatment of palm oil mill effluent (POME on a laboratory scale. Anaerobic digestion was performed in two-litre water jacketed biodigester type continuous stirred tank reactor (CSTR and operated at a thermophilic temperature (55 oC. As raw material, a real liquid waste (POME from palm oil mill was used. Fresh POME was obtained from seeding pond of PTPN II waste water treatment facility which has concentration of 39.7 g of VS/L and COD value of 59,000 mg/L. To gain precise results, complete recording and reliable equipment of reactor was employed. As the experimental results, for hydraulic retention time (HRT 8 days, VS decomposition rate of 63.5% and gas generation of 6.05-9.82 L/day were obtained, while for HRT 6 and 4 days, VS decomposition rate of 61.2, 53.3% and gas generation of  6.93-8.94  and  13.95-16.14 L/day were obtained respectively. Keywords—methane (CH4, palm oil mill effluent (POME, anaerobic digestion, thermophilic, green house gases (GHG

  9. Screening of Thermophilic Bacteria Produce Xylanase from Sapan Sungai Aro Hot Spring South Solok

    Science.gov (United States)

    Irdawati, I.; Syamsuardi, S.; Agustien, A.; Rilda, Y.

    2018-04-01

    xylanase is one of the enzymes with great prospects as hemicellulose hydrolyzing enzyme. Global annual market demand for this enzyme reach US 200 million. This enzyme catalyzes the xylan (hemicellulose) reactions breaking into xilooligosakarida and xylose. Xylanase can be applied to various industrial sectors such as bread, sugar xylose, biofuels, especially in bleaching paper (bleaching) pulp. Xylanase Isable to replace conventional chemical bleaching using chlorine that is not friendly for the environment. Currently xylanase production is extracted from the thermophilic bacteria for enzyme stability at high temperatures that are suitable for industrial applications. Thermophilic bacteria can be isolated from a hot spring, one of the which is a source of Sapan Sungai Aro Hot Spring, located in the district South Solok. The aim of this study was to select and identification of thermophilic bacteria can produce xylanase.This roomates is a descriptive study, which was Carried out in the Laboratory of Microbiology, Mathematic and Science Faculty of Padang State University, and Laboratory of Bacteriology, BasoVeterinary Research Center. The research procedure consisted of the preparation and sterilization of materials and tools, medium manufacturing, regeneration, selection and identification. Selection is performed by using a semiquantitative screening plate that contains xylan substrate. Identification is based on microscopic and biochemical characteristics until the genus level.Selection results Showed 12 out of 16 isolates had xilanolitik activity, with the highest activity is SSA2 with xilanolitik index of 0.74. The top five index producehigestxilanolitik isolates that are SSA2, SSA3 and SSA4 identified as Bacillus sp. 1., and SSAS6 and SSA7 is Bacillus sp. 2.

  10. Optimum Conditions for Uricase Enzyme Production by Gliomastix gueg

    Directory of Open Access Journals (Sweden)

    Atalla, M. M.

    2009-01-01

    Full Text Available Nineteen strains of microorganisms were screened for uricase production. Gliomastix gueg was recognized to produce high levels of the enzyme. The optimum fermentation conditions for uricase production by Gliomastix gueg were examined. Results showed that uric acid medium was the most favorable one, the optimum temperature was at 30ºC, and incubation period required for maximum production was 8 days with aeration level at 150 rpm and at pH 8.0. Sucrose proved to be the best carbon source, uric acid was found to be the best nitrogen source. Both, dipotassium hydrogen phosphate and ferrous chloride as well as some vitamins gave the highest amount of uricase by Gliomastix gueg.

  11. Co-digestion of bovine slaughterhouse wastes, cow manure, various crops and municipal solid waste at thermophilic conditions: a comparison with specific case running at mesophilic conditions.

    Science.gov (United States)

    Pagés-Díaz, J; Sárvári-Horváth, I; Pérez-Olmo, J; Pereda-Reyes, I

    2013-01-01

    A co-digestion process was evaluated when mixing different ratios of agro-industrial residues, i.e. bovine slaughterhouse waste (SB); cow manure (M); various crop residues (VC); and municipal solid waste (MSW) by anaerobic batch digestion under thermophilic conditions (55 °C). A selected study case at mesophilic condition (37 °C) was also investigated. The performance of the co-digestion was evaluated by kinetics (k(0)). The best kinetic results were obtained under thermophilic operation when a mixture of 22% w/w SB, 22% w/w M, 45% w/w VC and 11% w/w MSW was co-digested, which showed a proper combination of high values in r(s)CH(4) and k(0) (0.066 Nm(3)CH(4)/kgVS*d, 0.336 d(-1)) during the anaerobic process. The effect of temperature on methane yield (Y(CH4)), specific methane rate (r(s)CH(4)) and k(0) was also analyzed for a specific study case; there a mixture of 25% w/w of SB, 37.5% w/w of M, 37.5% of VC and 0% of MSW was used. Response variables were severely affected by mesophilic conditions, diminishing to at least 45% of the thermophilic values obtained for a similar mixture. The effect of temperature suggested that thermophilic conditions are suitable to treat these residues.

  12. Exogenous cellulases of thermophilic micromycetes. Pt. 1. Selection of producers

    Energy Technology Data Exchange (ETDEWEB)

    Kvesitadze, G; Kvachadze, L; Aleksidze, T; Chartishvili, D K

    1986-01-01

    More than 600 micromycetes - representatives of different genera have been investigated for their ability to produce exogenous cellulases. Most of the investigated cultures were found to produce these enzymes, 24 cultures being thermophilic, and 18 thermotolerant. Cellulase or its derivatives proved to be the most favourable carbon source for cellulase secretion. None of the thermophilic cultures studied manifested the ability of exogenous exoglucanase biosynthesis. Using UV-rays as mutagen, a mutant strain A. terreus T-49 has been obtained being characterized by an increased endo-glucanase and cellobiase activity, as compared to the initial strains. The cellulase preparations of thermophilic micromycetes contain one cellulasic component: endo-glucanase, or two: endo-glucanase and cellobiase.

  13. Optimum burnup of BAEC TRIGA research reactor

    International Nuclear Information System (INIS)

    Lyric, Zoairia Idris; Mahmood, Mohammad Sayem; Motalab, Mohammad Abdul; Khan, Jahirul Haque

    2013-01-01

    Highlights: ► Optimum loading scheme for BAEC TRIGA core is out-to-in loading with 10 fuels/cycle starting with 5 for the first reload. ► The discharge burnup ranges from 17% to 24% of U235 per fuel element for full power (3 MW) operation. ► Optimum extension of operating core life is 100 MWD per reload cycle. - Abstract: The TRIGA Mark II research reactor of BAEC (Bangladesh Atomic Energy Commission) has been operating since 1986 without any reshuffling or reloading yet. Optimum fuel burnup strategy has been investigated for the present BAEC TRIGA core, where three out-to-in loading schemes have been inspected in terms of core life extension, burnup economy and safety. In considering different schemes of fuel loading, optimization has been searched by only varying the number of fuels discharged and loaded. A cost function has been defined and evaluated based on the calculated core life and fuel load and discharge. The optimum loading scheme has been identified for the TRIGA core, the outside-to-inside fuel loading with ten fuels for each cycle starting with five fuels for the first reload. The discharge burnup has been found ranging from 17% to 24% of U235 per fuel element and optimum extension of core operating life is 100 MWD for each loading cycle. This study will contribute to the in-core fuel management of TRIGA reactor

  14. Archaeoglobus infectus sp. nov., a novel thermophilic, chemolithoheterotrophic archaeon isolated from a deep-sea rock collected at Suiyo Seamount, Izu-Bonin Arc, western Pacific Ocean.

    Science.gov (United States)

    Mori, Koji; Maruyama, Akihiko; Urabe, Tetsuro; Suzuki, Ken-Ichiro; Hanada, Satoshi

    2008-04-01

    A novel thermophilic, strictly anaerobic archaeon, designated strain Arc51T, was isolated from a rock sample collected from a deep-sea hydrothermal field in Suiyo Seamount, Izu-Bonin Arc, western Pacific Ocean. Cells of the isolate were irregular cocci with single flagella and exhibited blue-green fluorescence at 436 nm. The optimum temperature, pH and NaCl concentration for growth were 70 degrees C, pH 6.5 and 3 % (w/v), respectively. Strain Arc51T could grow on thiosulfate or sulfite as an electron acceptor in the presence of hydrogen. This strain required acetate as a carbon source for its growth, suggesting that the reductive acetyl CoA pathway for CO2 fixation was incomplete. In addition, coenzyme M (2-mercaptoethanesulfonic acid), which is a known methyl carrier in methanogenesis, was also a requirement for growth of the strain. Analysis of the 16S rRNA gene sequence revealed that the isolate was similar to members of the genus Archaeoglobus, with sequence similarities of 93.6-97.2 %; the closest relative was Archaeoglobus veneficus. Phylogenetic analyses of the dsrAB and apsA genes, encoding the alpha and beta subunits of dissimilatory sulfite reductase and the alpha subunit of adenosine-5'-phosphosulfate reductase, respectively, produced results similar to those inferred from comparisons based on the 16S rRNA gene sequence. On the basis of phenotypic and phylogenetic data, strain Arc51T represents a novel species of the genus Archaeoglobus, for which the name Archaeoglobus infectus sp. nov. is proposed. The type strain is Arc51T (=NBRC 100649T=DSM 18877T).

  15. Purification and biochemical characterization of a detergent-stable keratinase from a newly thermophilic actinomycete Actinomadura keratinilytica strain Cpt29 isolated from poultry compost.

    Science.gov (United States)

    Habbeche, Amina; Saoudi, Boudjema; Jaouadi, Bassem; Haberra, Soumaya; Kerouaz, Bilal; Boudelaa, Mokhtar; Badis, Abdelmalek; Ladjama, Ali

    2014-04-01

    An extracellular thermostable keratinase (KERAK-29) was purified and biochemically characterized from a thermophilic actinomycete Actinomadura keratinilytica strain Cpt29 newly isolated from Algerian poultry compost. The isolate exhibited high keratinase production when grown in chicken feather meal media (24,000 U/ml). Based on matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS) analysis, the purified enzyme is a monomer with a molecular mass of 29,233.10-Da. The data revealed that the 25 N-terminal residue sequence displayed by KERAK-29 was TQADPPSWGLNNIDRQTAFTKATSI, which showed high homology with those of Streptomyces proteases. This keratinase was completely inhibited by phenylmethanesulfonyl fluoride (PMSF) and diiodopropyl fluorophosphates (DFP), which suggests that it belongs to the serine protease family. Using keratin azure as a substrate, the optimum pH and temperature values for keratinase activity were pH 10 and 70°C, respectively. KERAK-29 was stable between 20 and 60°C and pH 3 and 10 for 5 and 120 h, respectively, and its thermoactivity and thermostability were enhanced in the presence of 5 mM Mn(2+). Its catalytic efficiency was higher than that of the KERAB keratinase from Streptomyces sp. strain AB1. KERAK-29 was also noted to show high keratinolytic activity and significant stability in the presence of detergents, which made it able to accomplish the entire feather-biodegradation process on its own. The ability of the A. keratinilytica strain Cpt29 to grow and produce substantial levels of keratinase using feather as a substrate could open new promising opportunities for the valorization of keratin-containing wastes and reduction of its impacts on the environment. Copyright © 2013 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  16. Indoor temperatures for optimum thermal comfort and human performance

    DEFF Research Database (Denmark)

    de Dear, R.; Arens, E. A.; Candido, C.

    2014-01-01

    A response by R. J. de Dear et al to a letter to the editor in response to their article "Progress in thermal comfort research over the last 20 years," published in a 2013 issue.......A response by R. J. de Dear et al to a letter to the editor in response to their article "Progress in thermal comfort research over the last 20 years," published in a 2013 issue....

  17. Effect of temperature on biodegradation of crude oil

    International Nuclear Information System (INIS)

    Zekri, A.; Chaalal, O.

    2005-01-01

    An active strain of anaerobic thermophilic bacteria was isolated from the environment of the United Arab Emirates. This project studied the effect of temperature, salinity and oil concentration on biodegradation of crude oil. Oil weight loss, microbial growth and the changes of the crude oil asphaltene concentration are used to evaluate the oil degradation by this strain. A series of batch experiments was performed to study the effects of bacteria on the degradation of crude oil. The effects of oil concentration, bacteria concentration, temperature and salinity on the biodegradation were investigated. The temperatures of the studied systems were varied between 35 and 75 o C and the salt concentrations were varied between 0 and 10%. Oil concentrations were ranged from 5 to 50% by volume. Experimental work showed the bacteria employed in this project were capable of surviving the harsh environment and degrading the crude oil at various conditions. Increasing the temperature increases the rate of oil degradation by bacteria. Increasing the oil concentration in general decreases the rate of bacteria oil degradation. Salinity plays a major role on the acceleration of biodegradation process of crude oil. An optimum salinity should be determined for every studied system. The finding of this project could be used in either the treatment of oil spill or in-situ stimulation of heavy oil wells. (author)

  18. Optimum Tilt Angle at Tropical Region

    Directory of Open Access Journals (Sweden)

    S Soulayman

    2015-02-01

    Full Text Available : One of the important parameters that affect the performance of a solar collector is its tilt angle with the horizon. This is because of the variation of tilt angle changes the amount of solar radiation reaching the collector surface. Meanwhile, is the rule of thumb, which says that solar collector Equator facing position is the best, is valid for tropical region? Thus, it is required to determine the optimum tilt as for Equator facing and for Pole oriented collectors. In addition, the question that may arise: how many times is reasonable for adjusting collector tilt angle for a definite value of surface azimuth angle? A mathematical model was used for estimating the solar radiation on a tilted surface, and to determine the optimum tilt angle and orientation (surface azimuth angle for the solar collector at any latitude. This model was applied for determining optimum tilt angle and orientation in the tropical zones, on a daily basis, as well as for a specific period. The optimum angle was computed by searching for the values for which the radiation on the collector surface is a maximum for a particular day or a specific period. The results reveal that changing the tilt angle 12 times in a year (i.e. using the monthly optimum tilt angle maintains approximately the total amount of solar radiation near the maximum value that is found by changing the tilt angle daily to its optimum value. This achieves a yearly gain in solar radiation of 11% to 18% more than the case of a solar collector fixed on a horizontal surface.

  19. Ethanol fermentation from molasses at high temperature by thermotolerant yeast Kluyveromyces sp. IIPE453 and energy assessment for recovery.

    Science.gov (United States)

    Dasgupta, Diptarka; Ghosh, Prasenjit; Ghosh, Debashish; Suman, Sunil Kumar; Khan, Rashmi; Agrawal, Deepti; Adhikari, Dilip K

    2014-10-01

    High temperature ethanol fermentation from sugarcane molasses B using thermophilic Crabtree-positive yeast Kluyveromyces sp. IIPE453 was carried out in batch bioreactor system. Strain was found to have a maximum specific ethanol productivity of 0.688 g/g/h with 92 % theoretical ethanol yield. Aeration and initial sugar concentration were tuning parameters to regulate metabolic pathways of the strain for either cell mass or higher ethanol production during growth with an optimum sugar to cell ratio 33:1 requisite for fermentation. An assessment of ethanol recovery from fermentation broth via simulation study illustrated that distillation-based conventional recovery was significantly better in terms of energy efficiency and overall mass recovery in comparison to coupled solvent extraction-azeotropic distillation technique for the same.

  20. Anaerobic digestion of whole stillage from dry-grind corn ethanol plant under mesophilic and thermophilic conditions.

    Science.gov (United States)

    Eskicioglu, Cigdem; Kennedy, Kevin J; Marin, Juan; Strehler, Benjamin

    2011-01-01

    Anaerobic digestion of whole stillage from a dry-grind corn-based ethanol plant was evaluated by batch and continuous-flow digesters under thermophilic and mesophilic conditions. At whole corn stillage concentrations of 6348 to 50,786 mg total chemical oxygen demand (TCOD)/L, at standard temperature (0 °C) and pressure (1 atm), preliminary biochemical methane potential assays produced 88±8 L (49±5 L CH4) and 96±19 L (65±14 L CH4) biogas per L stillage from mesophilic and thermophilic digesters, respectively. Continuous-flow studies for the full-strength stillage (TCOD=254 g/L) at organic loadings of 4.25, 6.30 and 9.05 g TCOD/L days indicated unstable performance for the thermophilic digester. Among the sludge retention times (SRTs) of 60, 45 and 30 days tested, the mesophilic digestion was successful only at 60 days-SRT which does not represent a practical operation time for a large scale bioethanol plant. Future laboratory studies will focus on different reactor configurations to reduce the SRT needed in the digesters. Copyright © 2010 Elsevier Ltd. All rights reserved.

  1. The Genetically Remote Pathogenic Strain NVH391-98 of the Bacillus cereus Group Represents the Cluster of Thermophilic Strains

    Energy Technology Data Exchange (ETDEWEB)

    Auger, Sandrine; Galleron, Nathalie; Bidnenko, Elena; Ehrlich, S. Dusko; Lapidus, Alla; Sorokin, Alexei

    2007-10-02

    Bacteria of the Bacillus cereus group are known to cause food poisoning. A rare phylogenetically remote strain, NVH391-98, was recently characterized to encode a particularly efficient cytotoxin K presumably responsible for food poisoning. This pathogenic strain and its close relatives can be phenotypically distinguished from other strains of the B. cereus group by the inability to grow at temperatures below 17 degrees C and by the ability to grow at temperatures from 48 to 53 degrees C. A temperate phage, phBC391A2, residing in the genome of NVH391-98 allows us to distinguish the three known members of this thermophilic strain cluster.

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

    Directory of Open Access Journals (Sweden)

    Begüm D. Topçuoğlu

    2016-08-01

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

  3. Developing an optimum protocol for thermoluminescence dosimetry with gr-200 chips using Taguchi method

    International Nuclear Information System (INIS)

    Sadeghi, Maryam; Faghihi, Reza; Sina, Sedigheh

    2017-01-01

    Thermoluminescence dosimetry (TLD) is a powerful technique with wide applications in personal, environmental and clinical dosimetry. The optimum annealing, storage and reading protocols are very effective in accuracy of TLD response. The purpose of this study is to obtain an optimum protocol for GR-200; LiF: Mg, Cu, P, by optimizing the effective parameters, to increase the reliability of the TLD response using Taguchi method. Taguchi method has been used in this study for optimization of annealing, storage and reading protocols of the TLDs. A number of 108 GR-200 chips were divided into 27 groups, each containing four chips. The TLDs were exposed to three different doses, and stored, annealed and read out by different procedures as suggested by Taguchi Method. By comparing the signal-to-noise ratios the optimum dosimetry procedure was obtained. According to the results, the optimum values for annealing temperature (de.C), Annealing Time (s), Annealing to Exposure time (d), Exposure to Readout time (d), Pre-heat Temperature (de.C), Pre-heat Time (s), Heating Rate (de.C/s), Maximum Temperature of Readout (de.C), readout time (s) and Storage Temperature (de.C) are 240, 90, 1, 2, 50, 0, 15, 240, 13 and -20, respectively. Using the optimum protocol, an efficient glow curve with low residual signals can be achieved. Using optimum protocol obtained by Taguchi method, the dosimetry can be effectively performed with great accuracy. (authors)

  4. Optimum moisture levels for biodegradation of mortality composting envelope materials.

    Science.gov (United States)

    Ahn, H K; Richard, T L; Glanville, T D

    2008-01-01

    Moisture affects the physical and biological properties of compost and other solid-state fermentation matrices. Aerobic microbial systems experience different respiration rates (oxygen uptake and CO2 evolution) as a function of moisture content and material type. In this study the microbial respiration rates of 12 mortality composting envelope materials were measured by a pressure sensor method at six different moisture levels. A wide range of respiration (1.6-94.2mg O2/g VS-day) rates were observed for different materials, with alfalfa hay, silage, oat straw, and turkey litter having the highest values. These four envelope materials may be particularly suitable for improving internal temperature and pathogen destruction rates for disease-related mortality composting. Optimum moisture content was determined based on measurements across a range that spans the maximum respiration rate. The optimum moisture content of each material was observed near water holding capacity, which ranged from near 60% to over 80% on a wet basis for all materials except a highly stabilized soil compost blend (optimum around 25% w.b.). The implications of the results for moisture management and process control strategies during mortality composting are discussed.

  5. Rheology and Microbiology of Sludge from a Thermophilic Aerobic Membrane Reactor

    Directory of Open Access Journals (Sweden)

    Alessandro Abbà

    2017-01-01

    Full Text Available A thermophilic aerobic membrane reactor (TAMR treating high-strength COD liquid wastes was submitted to an integrated investigation, with the aim of characterizing the biomass and its rheological behaviour. These processes are still scarcely adopted, also because the knowledge of their biology as well as of the physical-chemical properties of the sludge needs to be improved. In this paper, samples of mixed liquor were taken from a TAMR and submitted to fluorescent in situ hybridization for the identification and quantification of main bacterial groups. Measurements were also targeted at flocs features, filamentous bacteria, and microfauna, in order to characterize the sludge. The studied rheological properties were selected as they influence significantly the performances of membrane bioreactors (MBR and, in particular, of the TAMR systems that operate under thermophilic conditions (i.e., around 50°C with high MLSS concentrations (up to 200 gTS L−1. The proper description of the rheological behaviour of sludge represents a useful and fundamental aspect that allows characterizing the hydrodynamics of sludge suspension devoted to the optimization of the related processes. Therefore, in this study, the effects on the sludge rheology produced by the biomass concentration, pH, temperature, and aeration were analysed.

  6. Screening and characterization of phosphate solubilizing bacteria from isolate of thermophilic bacteria

    Science.gov (United States)

    Yulianti, Evy; Rakhmawati, Anna

    2017-08-01

    The aims of this study were to select bacteria that has the ability to dissolve phosphate from thermophilic bacteria isolates after the Merapi eruption. Five isolates of selected bacteria was characterized and continued with identification. Selection was done by using a pikovskaya selective medium. Bacterial isolates were grown in selective medium and incubated for 48 hours at temperature of 55 ° C. Characterization was done by looking at the cell and colony morphology, physiological and biochemical properties. Identification was done with the Profile Matching method based on the reference genus Oscillospira traced through Bergey's Manual of Determinative Bacteriology. Dendogram was created based on similarity index SSM. The results showed there were 14 isolates of bacteria that were able to dissolve phosphate indicated by a clear zone surrounding the bacterial colony on selective media. Five isolates were selected with the largest clear zone. Isolates D79, D92, D110a, D135 and D75 have different characters. The result of phenotypic characters identification with Genus Oscillospira profile has a percentage of 100% similarity to isolate D92 and D110a; 92.31% for isolates D79, and 84.6% for isolates D75 and D135. Dendogram generated from average linkage algorithm / UPGMA using the Simple Matching Coefficient (SSM) algorithms showed, isolate thermophilic bacteria D75 and D135 are combined together to form cluster 1. D110a and D92 form a sub cluster A. Sub cluster A and D79 form cluster 2

  7. Thermophilic enzymes and their applications in biocatalysis: a robust aldo-keto reductase.

    Science.gov (United States)

    Willies, Simon; Isupov, Misha; Littlechild, Jennifer

    2010-09-01

    Extremophiles are providing a good source of novel robust enzymes for use in biocatalysis for the synthesis of new drugs. This is particularly true for the enzymes from thermophilic organisms which are more robust than their mesophilic counterparts to the conditions required for industrial bio-processes. This paper describes a new aldo-keto reductase enzyme from a thermophilic eubacteria, Thermotoga maritima which can be used for the production of primary alcohols. The enzyme has been cloned and over-expressed in Escherichia coli and has been purified and subjected to full biochemical characterization. The aldo-keto reductase can be used for production of primary alcohols using substrates including benzaldehyde, 1,2,3,6-tetrahydrobenzaldehyde and para-anisaldehyde. It is stable up to 80 degrees C, retaining over 60% activity for 5 hours at this temperature. The enzyme at pH 6.5 showed a preference for the forward, carbonyl reduction. The enzyme showed moderate stability with organic solvents, and retained 70% activity in 20% (v/v) isopropanol or DMSO. These properties are favourable for its potential industrial applications.

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

    Science.gov (United States)

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

    2013-09-01

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

  9. Dispersal of thermophilic beetles across the intercontinental Arctic forest belt during the early Eocene.

    Science.gov (United States)

    Brunke, Adam J; Chatzimanolis, Stylianos; Metscher, Brian D; Wolf-Schwenninger, Karin; Solodovnikov, Alexey

    2017-10-11

    Massive biotic change occurred during the Eocene as the climate shifted from warm and equable to seasonal and latitudinally stratified. Mild winter temperatures across Arctic intercontinental land bridges permitted dispersal of frost-intolerant groups until the Eocene-Oligocene boundary, while trans-Arctic dispersal in thermophilic groups may have been limited to the early Eocene, especially during short-lived hyperthermals. Some of these lineages are now disjunct between continents of the northern hemisphere. Although Eocene climate change may have been one of the most important drivers of these ancient patterns in modern animal and plant distributions, its particular events are rarely implicated or correlated with group-specific climatic requirements. Here we explored the climatic and geological drivers of a particularly striking Neotropical-Oriental disjunct distribution in the rove beetle Bolitogyrus, a suspected Eocene relict. We integrated evidence from Eocene fossils, distributional and climate data, paleoclimate, paleogeography, and phylogenetic divergence dating to show that intercontinental dispersal of Bolitogyrus ceased in the early Eocene, consistent with the termination of conditions required by thermophilic lineages. These results provide new insight into the poorly known and short-lived Arctic forest community of the Early Eocene and its surviving lineages.

  10. Developed Hybrid Model for Propylene Polymerisation at Optimum Reaction Conditions

    Directory of Open Access Journals (Sweden)

    Mohammad Jakir Hossain Khan

    2016-02-01

    Full Text Available A statistical model combined with CFD (computational fluid dynamic method was used to explain the detailed phenomena of the process parameters, and a series of experiments were carried out for propylene polymerisation by varying the feed gas composition, reaction initiation temperature, and system pressure, in a fluidised bed catalytic reactor. The propylene polymerisation rate per pass was considered the response to the analysis. Response surface methodology (RSM, with a full factorial central composite experimental design, was applied to develop the model. In this study, analysis of variance (ANOVA indicated an acceptable value for the coefficient of determination and a suitable estimation of a second-order regression model. For better justification, results were also described through a three-dimensional (3D response surface and a related two-dimensional (2D contour plot. These 3D and 2D response analyses provided significant and easy to understand findings on the effect of all the considered process variables on expected findings. To diagnose the model adequacy, the mathematical relationship between the process variables and the extent of polymer conversion was established through the combination of CFD with statistical tools. All the tests showed that the model is an excellent fit with the experimental validation. The maximum extent of polymer conversion per pass was 5.98% at the set time period and with consistent catalyst and co-catalyst feed rates. The optimum conditions for maximum polymerisation was found at reaction temperature (RT 75 °C, system pressure (SP 25 bar, and 75% monomer concentration (MC. The hydrogen percentage was kept fixed at all times. The coefficient of correlation for reaction temperature, system pressure, and monomer concentration ratio, was found to be 0.932. Thus, the experimental results and model predicted values were a reliable fit at optimum process conditions. Detailed and adaptable CFD results were capable

  11. Common Core: Teaching Optimum Topic Exploration (TOTE)

    Science.gov (United States)

    Karge, Belinda Dunnick; Moore, Roxane Kushner

    2015-01-01

    The Common Core has become a household term and yet many educators do not understand what it means. This article explains the historical perspectives of the Common Core and gives guidance to teachers in application of Teaching Optimum Topic Exploration (TOTE) necessary for full implementation of the Common Core State Standards. An effective…

  12. Optimum fiber distribution in singlewall corrugated fiberboard

    Science.gov (United States)

    Millard W. Johnson; Thomas J. Urbanik; William E. Denniston

    1979-01-01

    Determining optimum distribution of fiber through rational design of corrugated fiberboard could result in significant reductions in fiber required to meet end-use conditions, with subsequent reductions in price pressure and extension of the softwood timber supply. A theory of thin plates under large deformations is developed that is both kinematically and physically...

  13. Calculations enable optimum design of magnetic brake

    Science.gov (United States)

    Kosmahl, H. G.

    1966-01-01

    Mathematical analysis and computations determine optimum magnetic coil configurations for a magnetic brake which controllably decelerates a free falling load to a soft stop. Calculations on unconventionally wound coils determine the required parameters for the desired deceleration with minimum electrical energy supplied to the stationary coil.

  14. Genotype x environment interaction and optimum resource ...

    African Journals Online (AJOL)

    ... x E) interaction and to determine the optimum resource allocation for cassava yield trials. The effects of environment, genotype and G x E interaction were highly significant for all yield traits. Variations due to G x E interaction were greater than those due to genotypic differences for all yield traits. Genotype x location x year ...

  15. Determination of the Optimum Thickness of Approximately ...

    African Journals Online (AJOL)

    In an attempt to conserve the world's scarce energy and material resources, a balance between the cost of heating a material and the optimum thickness of the material becomes vey essential. One of such materials is the local cast aluminium pot commonly used as cooking ware in Nigeria. This paper therefore sets up a ...

  16. Development of the optimum rotor theories

    DEFF Research Database (Denmark)

    Okulov, Valery; Sørensen, Jens Nørkær; van Kuik, Gijs A.M.

    The purpose of this study is the examination of optimum rotor theories with ideal load distributions along the blades, to analyze some of the underlying ideas and concepts, as well as to illuminate them. The book gives the historical background of the issue and presents the analysis of the problems...

  17. Discovery and characterization of thermophilic limonene-1,2-epoxide hydrolases from hot spring metagenomic libraries

    DEFF Research Database (Denmark)

    Ferrandi, Erica Elisa; Sayer, Christopher; Isupov, Michail N.

    2015-01-01

    thermophilic sources, have higher optimal temperatures and apparent melting temperatures than Re-LEH. The new LEH enzymes have been crystallized and their structures solved to high resolution in the native form and in complex with the inhibitor valpromide for Tomsk-LEH and poly(ethylene glycol) for CH55-LEH......,2-epoxide hydrolase (LEH) family of enzymes. These two LEHs (Tomsk-LEH and CH55-LEH) show EH activities towards different epoxide substrates, differing in most cases from those previously identified for Rhodococcus erythropolis (Re-LEH) in terms of stereoselectivity. Tomsk-LEH and CH55-LEH, both from....... The structural analysis has provided insights into the LEH mechanism, substrate specificity and stereoselectivity of these new LEH enzymes, which has been supported by mutagenesis studies....

  18. A Combination of Stable Isotope Probing, Illumina Sequencing, and Co-occurrence Network to Investigate Thermophilic Acetate- and Lactate-Utilizing Bacteria.

    Science.gov (United States)

    Sun, Weimin; Krumins, Valdis; Dong, Yiran; Gao, Pin; Ma, Chunyan; Hu, Min; Li, Baoqin; Xia, Bingqing; He, Zijun; Xiong, Shangling

    2018-01-01

    Anaerobic digestion is a complicated microbiological process that involves a wide diversity of microorganisms. Acetate is one of the most important intermediates, and interactions between acetate-oxidizing bacteria and archaea could play an important role in the formation of methane in anoxic environments. Anaerobic digestion at thermophilic temperatures is known to increase methane production, but the effects on the microbial community are largely unknown. In the current study, stable isotope probing was used to characterize acetate- and lactate-oxidizing bacteria in thermophilic anaerobic digestion. In microcosms fed 13 C-acetate, bacteria related to members of Clostridium, Hydrogenophaga, Fervidobacterium, Spirochaeta, Limnohabitans, and Rhodococcus demonstrated elevated abundances of 13 C-DNA fractions, suggesting their activities in acetate oxidation. In the treatments fed 13 C-lactate, Anaeromyxobacter, Desulfobulbus, Syntrophus, Cystobacterineae, and Azospira were found to be the potential thermophilic lactate utilizers. PICRUSt predicted that enzymes related to nitrate and nitrite reduction would be enriched in 13 C-DNA fractions, suggesting that the acetate and lactate oxidation may be coupled with nitrate and/or nitrite reduction. Co-occurrence network analysis indicated bacterial taxa not enriched in 13 C-DNA fractions that may also play a critical role in thermophilic anaerobic digestion.

  19. An efficient Azorean thermophilic consortium for lignocellulosic biomass degradation

    OpenAIRE

    Martins, Rita; Teixeira, Mário; Toubarro, Duarte; Simões, Nelson; Domingues, Lucília; Teixeira, J. A.

    2015-01-01

    [Excerpt] Lignocellulosic plant biomass is being envisioned by biorefinery industry as an alternative to current petroleum platform because of the large scale availability, low cost and environmentally benign production. The industrial bioprocessing designed to transform lignocellulosic biomass into biofuels are harsh and the enzymatic reactions may be severely compromised reducing the production of fermentable sugars from lignocellulosic biomass. Thermophilic bacteria consortium are a potent...

  20. 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

  1. Hydrogenomics of the extremely thermophilic bacterium Caldicellulosiruptor saccharolyticus

    NARCIS (Netherlands)

    Werken, van de H.J.G.; Verhaart, M.R.A.; Vanfossen, A.L.; Willquist, K.; Lewis, D.L.; Nichols, J.D.; Goorissen, H.P.; Mongodin, E.F.; Nelson, K.E.; Niel, van E.W.J.; Stams, A.J.M.; Ward, D.E.; Vos, de W.M.; Oost, van der J.; Kelly, R.M.; Kengen, S.W.M.

    2008-01-01

    Caldicellulosiruptor saccharolyticus is an extremely thermophilic, gram-positive anaerobe which ferments cellulose-, hemicellulose- and pectin-containing biomass to acetate, CO(2), and hydrogen. Its broad substrate range, high hydrogen-producing capacity, and ability to coutilize glucose and xylose

  2. Production of α-amylase from some thermophilic Aspergillus species ...

    African Journals Online (AJOL)

    In this study, thermostable amylase activities of some thermophilic Aspergillus species were evaluated. The suitable medium and microorganisms for α-amylase synthesis were selected. Subsequently, the α-amylase activity of the microorganism was researched. In the measurements made on the 7th day of production on ...

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

    International Nuclear Information System (INIS)

    Beblo, K.; Wirth, R.; Huber, H.; Douki, T.; Schmalz, G.; Rachel, R.

    2011-01-01

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

  4. Bayesian prediction of bacterial growth temperature range based on genome sequences

    DEFF Research Database (Denmark)

    Jensen, Dan Børge; Vesth, Tammi Camilla; Hallin, Peter Fischer

    2012-01-01

    Background: The preferred habitat of a given bacterium can provide a hint of which types of enzymes of potential industrial interest it might produce. These might include enzymes that are stable and active at very high or very low temperatures. Being able to accurately predict this based...... on a genomic sequence, would thus allow for an efficient and targeted search for production organisms, reducing the need for culturing experiments. Results: This study found a total of 40 protein families useful for distinction between three thermophilicity classes (thermophiles, mesophiles and psychrophiles...... that protein families associated with specific thermophilicity classes can provide effective input data for thermophilicity prediction, and that the naive Bayesian approach is effective for such a task. The program created for this study is able to efficiently distinguish between thermophilic, mesophilic...

  5. 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

  6. Optimum Operational Parameters for Yawed Wind Turbines

    Directory of Open Access Journals (Sweden)

    David A. Peters

    2011-01-01

    Full Text Available A set of systematical optimum operational parameters for wind turbines under various wind directions is derived by using combined momentum-energy and blade-element-energy concepts. The derivations are solved numerically by fixing some parameters at practical values. Then, the interactions between the produced power and the influential factors of it are generated in the figures. It is shown that the maximum power produced is strongly affected by the wind direction, the tip speed, the pitch angle of the rotor, and the drag coefficient, which are specifically indicated by figures. It also turns out that the maximum power can take place at two different optimum tip speeds in some cases. The equations derived herein can also be used in the modeling of tethered wind turbines which can keep aloft and deliver energy.

  7. OPTIMUM PROGRAMMABLE CONTROL OF UNMANNED FLYING VEHICLE

    Directory of Open Access Journals (Sweden)

    A. А. Lobaty

    2012-01-01

    Full Text Available The paper considers an analytical synthesis problem pertaining to programmable control of an unmanned flying vehicle while steering it to the fixed space point. The problem has been solved while applying a maximum principle which takes into account a final control purpose and its integral expenses. The paper presents an optimum law of controlling overload variation of a flying vehicle that has been obtained analytically

  8. Techniques for evaluating optimum data center operation

    Science.gov (United States)

    Hamann, Hendrik F.; Rodriguez, Sergio Adolfo Bermudez; Wehle, Hans-Dieter

    2017-06-14

    Techniques for modeling a data center are provided. In one aspect, a method for determining data center efficiency is provided. The method includes the following steps. Target parameters for the data center are obtained. Technology pre-requisite parameters for the data center are obtained. An optimum data center efficiency is determined given the target parameters for the data center and the technology pre-requisite parameters for the data center.

  9. Probabilistic studies for safety at optimum cost

    International Nuclear Information System (INIS)

    Pitner, P.

    1999-01-01

    By definition, the risk of failure of very reliable components is difficult to evaluate. How can the best strategies for in service inspection and maintenance be defined to limit this risk to an acceptable level at optimum cost? It is not sufficient to design structures with margins, it is also essential to understand how they age. The probabilistic approach has made it possible to develop well proven concepts. (author)

  10. Detection of putatively thermophilic anaerobic methanotrophs in diffuse hydrothermal vent fluids.

    Science.gov (United States)

    Merkel, Alexander Y; Huber, Julie A; Chernyh, Nikolay A; Bonch-Osmolovskaya, Elizaveta A; Lebedinsky, Alexander V

    2013-02-01

    The anaerobic oxidation of methane (AOM) is carried out by a globally distributed group of uncultivated Euryarchaeota, the anaerobic methanotrophic arachaea (ANME). In this work, we used G+C analysis of 16S rRNA genes to identify a putatively thermophilic ANME group and applied newly designed primers to study its distribution in low-temperature diffuse vent fluids from deep-sea hydrothermal vents. We found that the G+C content of the 16S rRNA genes (P(GC)) is significantly higher in the ANME-1GBa group than in other ANME groups. Based on the positive correlation between the P(GC) and optimal growth temperatures (T(opt)) of archaea, we hypothesize that the ANME-1GBa group is adapted to thrive at high temperatures. We designed specific 16S rRNA gene-targeted primers for the ANME-1 cluster to detect all phylogenetic groups within this cluster, including the deeply branching ANME-1GBa group. The primers were successfully tested both in silico and in experiments with sediment samples where ANME-1 phylotypes had previously been detected. The primers were further used to screen for the ANME-1 microorganisms in diffuse vent fluid samples from deep-sea hydrothermal vents in the Pacific Ocean, and sequences belonging to the ANME-1 cluster were detected in four individual vents. Phylotypes belonging to the ANME-1GBa group dominated in clone libraries from three of these vents. Our findings provide evidence of existence of a putatively extremely thermophilic group of methanotrophic archaea that occur in geographically and geologically distinct marine hydrothermal habitats.

  11. The optimum lead thickness for lead-activation detectors

    International Nuclear Information System (INIS)

    Si Fenni; Hu Qingyuan

    2009-01-01

    The optimum lead thickness for lead-activation detectors has been studied in this paper. First existence of the optimum lead thickness is explained theoretically. Then the optimum lead thickness is obtained by two methods, MCNP5 calculation and mathematical estimation. At last factors which affect the optimum lead thickness are discussed. It turns out that the optimum lead thickness is irrelevant to incident neutron energies. It is recommended 2.5 cm generally.

  12. Temperatura óptima de germinación y patrones de imbibición de las semillas de Albizia lebbeck, Gliricidia sepium y Bauhinia purpurea Optimum germination temperature and imbibition patterns of the seeds from Albizia lebbeck, Gliricidia sepium and Bauhinia purpurea

    Directory of Open Access Journals (Sweden)

    J Reino

    2008-09-01

    substratum (constant 25ºC and three alternate ones: 25/30ºC, 25/35ºC and 25/40ºC. Before seeding the seeds of A. lebbeck were scarified (water at 80ºC/2'. For the imbibition pattern the seeds were put on filter paper moist with purified water according to the optimum germination temperature, under white fluorescent light and at different imbibition times. In the fresh seeds of all the species the highest percentages of final germination were obtained at alternate temperature of 25/35ºC and in the aged ones at 25/30ºC. With regards to the imbibition pattern they all followed a three-phase pattern of water absorption. The fresh and aged seeds of G. sepium showed a very similar imbibition pattern, however the fresh seeds of the other species presented higher hydration rate than the aged ones and consequently they reached faster the start of phase III of the imbibition pattern (i.e. visible germination. The range of optimum temperature for the germination of aged seeds was concluded to be 25/30 ºC and for the fresh ones it was 25/35 ºC and both showed a three-phase pattern of water absorption when the seeding was carried out at optimum germination temperature.

  13. Cloning, sequencing, and expression of dnaK-operon proteins from the thermophilic bacterium Thermus thermophilus.

    Science.gov (United States)

    Osipiuk, J; Joachimiak, A

    1997-09-12

    We propose that the dnaK operon of Thermus thermophilus HB8 is composed of three functionally linked genes: dnaK, grpE, and dnaJ. The dnaK and dnaJ gene products are most closely related to their cyanobacterial homologs. The DnaK protein sequence places T. thermophilus in the plastid Hsp70 subfamily. In contrast, the grpE translated sequence is most similar to GrpE from Clostridium acetobutylicum, a Gram-positive anaerobic bacterium. A single promoter region, with homology to the Escherichia coli consensus promoter sequences recognized by the sigma70 and sigma32 transcription factors, precedes the postulated operon. This promoter is heat-shock inducible. The dnaK mRNA level increased more than 30 times upon 10 min of heat shock (from 70 degrees C to 85 degrees C). A strong transcription terminating sequence was found between the dnaK and grpE genes. The individual genes were cloned into pET expression vectors and the thermophilic proteins were overproduced at high levels in E. coli and purified to homogeneity. The recombinant T. thermophilus DnaK protein was shown to have a weak ATP-hydrolytic activity, with an optimum at 90 degrees C. The ATPase was stimulated by the presence of GrpE and DnaJ. Another open reading frame, coding for ClpB heat-shock protein, was found downstream of the dnaK operon.

  14. Expression and properties of the highly alkalophilic phenylalanine ammonia-lyase of thermophilic Rubrobacter xylanophilus.

    Directory of Open Access Journals (Sweden)

    Klaudia Kovács

    Full Text Available The sequence of a phenylalanine ammonia-lyase (PAL; EC: 4.3.1.24 of the thermophilic and radiotolerant bacterium Rubrobacter xylanophilus (RxPAL was identified by screening the genomes of bacteria for members of the phenylalanine ammonia-lyase family. A synthetic gene encoding the RxPAL protein was cloned and overexpressed in Escherichia coli TOP 10 in a soluble form with an N-terminal His6-tag and the recombinant RxPAL protein was purified by Ni-NTA affinity chromatography. The activity assay of RxPAL with l-phenylalanine at various pH values exhibited a local maximum at pH 8.5 and a global maximum at pH 11.5. Circular dichroism (CD studies showed that RxPAL is associated with an extensive α-helical character (far UV CD and two distinctive near-UV CD peaks. These structural characteristics were well preserved up to pH 11.0. The extremely high pH optimum of RxPAL can be rationalized by a three-dimensional homology model indicating possible disulfide bridges, extensive salt-bridge formation and an excess of negative electrostatic potential on the surface. Due to these properties, RxPAL may be a candidate as biocatalyst in synthetic biotransformations leading to unnatural l- or d-amino acids or as therapeutic enzyme in treatment of phenylketonuria or leukemia.

  15. [Isolation and identification of seven thermophilic and anaerobic bacteria from hot springs in Tengchong Rehai].

    Science.gov (United States)

    Lu, Yueqing; Chen, Bo; Liu, Xiaoli; Ji, Xiuling; Wei, Yunlin; Lin, Lianbing

    2009-09-01

    In order to study the taxonomic characteristic and physiological, biochemical properties of anaerobic bacteria from hot springs in Tengchong Rehai, Yunnan Province, China. Using Hungate anaerobic technique We isolated seven strains from hot springs in Tengchong Rehai, Yunnan province, and analyzed their 16S rRNA gene sequences. The seven isolates were rod-shaped, Gram-negative, obligate anaerobe, and spores formation was not observed. All strains could grow well at 70 degrees C. Growth of strain RH0802 occurred between 60 and 80 degrees C, optimally around 70 degrees C. The pH range for its growth was between 5.5 and 8.5, with an optimum around 7.0. Strain RH0802 grew on a wide range of carbon sources, including glucose, starch, mannitol, mannose, ribose, maltose, cellobiose, xylose, fructose, galactose, xylan and glycerol, but it could not utilize sucrose or pyruvate. 16S rRNA gene phylogenetic analysis showed that the maximum similarity between the five strains and the strains of genus Caldanaerobacter was up to 98%, except RH0804 and RH0806, which reached to 96% and 93%, respectively. The two isolates were presumed to be potential novel species. The GenBank accession numbers of RH0802 to RH0808 were FJ748766, FJ748762, FJ748761, FJ748763, FJ748765, FJ748764 and FJ748767. The results showed that the seven thermophilic anaerobes belonged to the genus Caldanaerobacter.

  16. Mesophilic and thermophilic conditions select for unique but highly parallel microbial communities to perform carboxylate platform biomass conversion.

    Directory of Open Access Journals (Sweden)

    Emily B Hollister

    Full Text Available The carboxylate platform is a flexible, cost-effective means of converting lignocellulosic materials into chemicals and liquid fuels. Although the platform's chemistry and engineering are well studied, relatively little is known about the mixed microbial communities underlying its conversion processes. In this study, we examined the metagenomes of two actively fermenting platform communities incubated under contrasting temperature conditions (mesophilic 40°C; thermophilic 55 °C, but utilizing the same inoculum and lignocellulosic feedstock. Community composition segregated by temperature. The thermophilic community harbored genes affiliated with Clostridia, Bacilli, and a Thermoanaerobacterium sp, whereas the mesophilic community metagenome was composed of genes affiliated with other Clostridia and Bacilli, Bacteriodia, γ-Proteobacteria, and Actinobacteria. Although both communities were able to metabolize cellulosic materials and shared many core functions, significant differences were detected with respect to the abundances of multiple Pfams, COGs, and enzyme families. The mesophilic metagenome was enriched in genes related to the degradation of arabinose and other hemicellulose-derived oligosaccharides, and the production of valerate and caproate. In contrast, the thermophilic community was enriched in genes related to the uptake of cellobiose and the transfer of genetic material. Functions assigned to taxonomic bins indicated that multiple community members at either temperature had the potential to degrade cellulose, cellobiose, or xylose and produce acetate, ethanol, and propionate. The results of this study suggest that both metabolic flexibility and functional redundancy contribute to the platform's ability to process lignocellulosic substrates and are likely to provide a degree of stability to the platform's fermentation processes.

  17. Bio-hydrolysis and bio-hydrogen production from food waste by thermophilic and hyperthermophilic anaerobic process.

    Science.gov (United States)

    Algapani, Dalal E; Qiao, Wei; Su, Min; di Pumpo, Francesca; Wandera, Simon M; Adani, Fabrizio; Dong, Renjie

    2016-09-01

    High-temperature pretreatment plays a key role in the anaerobic digestion of food waste (FW). However, the suitable temperature is not yet determined. In this work, a long-term experiment was conducted to compare hydrolysis, acidogenesis, acetogenesis, and hydrogen production at 55°C and 70°C, using real FW in CSTR reactors. The results obtained indicated that acidification was the rate-limiting step at both temperatures with similar process kinetics characterizations. However, the thermophilic pretreatment was more advantageous than the hyperthermophilic with suspended solids solubilization of 47.7% and 29.5% and total VFA vs. soluble COD ratio of 15.2% and 4.9%, for thermophilic and hyperthermophilic treatment, respectively, with a hydrolytic reaction time (HRT) of 10days and an OLR of 14kgCOD/m(3)d. Moreover, stable hydrogen yield (70.7ml-H2/gVSin) and content in off gas (58.6%) was achieved at HRT 5days, pH 5.5, and temperature of 55°C, as opposed to 70°C. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Enrichment of Thermophilic Propionate-Oxidizing Bacteria in Syntrophy with Methanobacterium thermoautotrophicum or Methanobacterium thermoformicicum

    OpenAIRE

    Stams, Alfons J. M.; Grolle, Katja C. F.; Frijters, Carla T. M.; Van Lier, Jules B.

    1992-01-01

    Thermophilic propionate-oxidizing, proton-reducing bacteria were enriched from the granular methanogenic sludge of a bench-scale upflow anaerobic sludge bed reactor operated at 55°C with a mixture of volatile fatty acids as feed. Thermophilic hydrogenotrophic methanogens had a high decay rate. Therefore, stable, thermophilic propionate-oxidizing cultures could not be obtained by using the usual enrichment procedures. Stable and reproducible cultivation was possible by enrichment in hydrogen-p...

  19. Thermophilic versus Mesophilic Anaerobic Digestion of Sewage Sludge: A Comparative Review

    Directory of Open Access Journals (Sweden)

    Getachew D. Gebreeyessus

    2016-06-01

    Full Text Available During advanced biological wastewater treatment, a huge amount of sludge is produced as a by-product of the treatment process. Hence, reuse and recovery of resources and energy from the sludge is a big technological challenge. The processing of sludge produced by Wastewater Treatment Plants (WWTPs is massive, which takes up a big part of the overall operational costs. In this regard, anaerobic digestion (AD of sewage sludge continues to be an attractive option to produce biogas that could contribute to the wastewater management cost reduction and foster the sustainability of those WWTPs. At the same time, AD reduces sludge amounts and that again contributes to the reduction of the sludge disposal costs. However, sludge volume minimization remains, a challenge thus improvement of dewatering efficiency is an inevitable part of WWTP operation. As a result, AD parameters could have significant impact on sludge properties. One of the most important operational parameters influencing the AD process is temperature. Consequently, the thermophilic and the mesophilic modes of sludge AD are compared for their pros and cons by many researchers. However, most comparisons are more focused on biogas yield, process speed and stability. Regarding the biogas yield, thermophilic sludge AD is preferred over the mesophilic one because of its faster biochemical reaction rate. Equally important but not studied sufficiently until now was the influence of temperature on the digestate quality, which is expressed mainly by the sludge dewateringability, and the reject water quality (chemical oxygen demand, ammonia nitrogen, and pH. In the field of comparison of thermophilic and mesophilic digestion process, few and often inconclusive research, unfortunately, has been published so far. Hence, recommendations for optimized technologies have not yet been done. The review presented provides a comparison of existing sludge AD technologies and the gaps that need to be filled so

  20. Deposition uniformity, particle nucleation and the optimum conditions for CVD in multi-wafer furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Griffiths, S.K.; Nilson, R.H.

    1996-06-01

    A second-order perturbation solution describing the radial transport of a reactive species and concurrent deposition on wafer surfaces is derived for use in optimizing CVD process conditions. The result is applicable to a variety of deposition reactions and accounts for both diffusive and advective transport, as well as both ordinary and Knudsen diffusion. Based on the first-order approximation, the deposition rate is maximized subject to a constraint on the radial uniformity of the deposition rate. For a fixed reactant mole fraction, the optimum pressure and optimum temperature are obtained using the method of Lagrange multipliers. This yields a weak one-sided maximum; deposition rates fall as pressures are reduced but remain nearly constant at all pressures above the optimum value. The deposition rate is also maximized subject to dual constraints on the uniformity and particle nucleation rate. In this case, the optimum pressure, optimum temperature and optimum reactant fraction are similarly obtained, and the resulting maximum deposition rate is well defined. These results are also applicable to CVI processes used in composites manufacturing.

  1. Determination of Optimum Condition of Leucine Content in Beef Protein Hydrolysate using Response Surface Methodology

    International Nuclear Information System (INIS)

    Siti Roha Ab Mutalib; Zainal Samicho; Noriham Abdullah

    2016-01-01

    The aim of this study is to determine the optimum condition of leucine content in beef hydrolysate. Beef hydrolysate was prepared by enzymatic hydrolysis using bromelain enzyme produced from pineapple peel. Parameter conditions such as concentration of bromelain, hydrolysis temperature and hydrolysis time were assessed to obtain the optimum leucine content of beef hydrolysate according to experimental design which was recommended by response surface methodology (RSM). Leucine content in beef hydrolysate was determined using AccQ. Tag amino acid analysis method using high performance liquid chromatography (HPLC). The condition of optimum leucine content was at bromelain concentration of 1.38 %, hydrolysis temperature of 42.5 degree Celcius and hydrolysis time of 31.59 hours with the predicted leucine content of 26.57 %. The optimum condition was verified with the leucine value obtained was 26.25 %. Since there was no significant difference (p>0.05) between the predicted and verified leucine values, thus it indicates that the predicted optimum condition by RSM can be accepted to predict the optimum leucine content in beef hydrolysate. (author)

  2. Isolation and Phylogenetic Analysis of Thermophile Community Within Tanjung Sakti Hot Spring, South Sumatera, Indonesia

    Directory of Open Access Journals (Sweden)

    Heni Yohandini

    2015-07-01

    Full Text Available A community of thermophiles within Tanjung Sakti Hot Spring (South Sumatera have been cultivated and identified based on 16S ribosomal RNA gene sequence. The hot spring has temperature 80 °C–91 °C and pH 7–8. We used a simple method for culturing the microbes, by enriching the spring water with nutrient broth media. Phylogenetic analysis showed that the method could recover microbes, which clustered within four distinct taxonomic groups: Anoxybacillus, Geobacillus, Brevibacillus, and Bacillus. These microbes closely related to Anoxybacillus rupiensis, Anoxybacillus flavithermus, Geobacillus pallidus, Brevibacillus thermoruber, Bacillus licheniformis, and Bacillus thermoamylovorans. The 16S ribosomal RNA gene sequence of one isolate only had 96% similarity with Brevibacillus sequence in GenBank.

  3. Converting mesophilic upflow sludge blanket (UASB) reactors to thermophilic by applying axenic methanogenic culture bioaugmentation

    DEFF Research Database (Denmark)

    Zhu, Xinyu; Treu, Laura; Kougias, Panagiotis G.

    2018-01-01

    on the microbial consortium. The adaptation of microbial community to a new environment or condition can be accelerated by a process known as “bioaugmentation” or “microbial community manipulation”, during which exogenous microorganisms harbouring specific metabolic activities are introduced to the reactor....... The aim of the current study was to rapidly convert the operational temperature of up-flow anaerobic sludge blanket (UASB) reactors from mesophilic to thermophilic conditions by applying microbial community manipulation techniques. Three different bioaugmentation strategies were compared and it was proven...... that the injection of axenic methanogenic culture was the most efficient approach leading to improved biomethanation process with 40% higher methane production rate compared to the control reactor. Microbial community analyses revealed that during bioaugmentation, the exogenous hydrogenotrophic methanogen could...

  4. 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....... Transient expression in tobacco and stable expression in transgenic Arabidopsis showed that both enzymes were expressed in an active form with temperature optima at 85 °C. Transgenic Arabidopsis accumulating heterologous endo-xylanases appeared phenotypically normal and were fully fertile. The highest...... xylanase activity in Arabidopsis was found in dry stems indicating that the enzymes were not degraded during stem senescence. High levels of enzyme activity were maintained in cell-free extracts from dry transgenic stems during incubation at 85 °C for 24 h. Analysis of cell wall polysaccharides after heat...

  5. Improved lignocellulose conversion to biofuels with thermophilic bacteria and thermostable enzymes.

    Science.gov (United States)

    Bhalla, Aditya; Bansal, Namita; Kumar, Sudhir; Bischoff, Kenneth M; Sani, Rajesh K

    2013-01-01

    Second-generation feedstock, especially nonfood lignocellulosic biomass is a potential source for biofuel production. Cost-intensive physical, chemical, biological pretreatment operations and slow enzymatic hydrolysis make the overall process of lignocellulosic conversion into biofuels less economical than available fossil fuels. Lignocellulose conversions carried out at ≤ 50 °C have several limitations. Therefore, this review focuses on the importance of thermophilic bacteria and thermostable enzymes to overcome the limitations of existing lignocellulosic biomass conversion processes. The influence of high temperatures on various existing lignocellulose conversion processes and those that are under development, including separate hydrolysis and fermentation, simultaneous saccharification and fermentation, and extremophilic consolidated bioprocess are also discussed. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. Hydrogen evolution by a thermophilic blue-green alga. Mastigocladus laminosus

    Energy Technology Data Exchange (ETDEWEB)

    Mirua, Y; Yokoyama, H; Kanaoka, K; Saito, S; Iwasa, K; Okazaki, M; Komemushi, S

    1980-01-01

    The thermophillic blue-green alga (cyanobacterium), Mastigocladus laminosus isolated from a hot spring, evolved hydrogen gas under nitrogen-starved conditions in light when algal cells were grown in a nitrate-free medium. Cells grown in a nitrate-medium evolved no detectable hydrogen gas in light. The optimal temperature and pH for hydrogen evolution were 44-49 degrees C and 7.0-7.5. High activity of hydrogen evolution, 1.6 ml H/sub 2//mg chl.hr, was induced when algal cells grown in the nitrate medium were actively forming heterocysts in the nitrate-free medium in air. Hydrogen evolution in light was depressed by nitrogen gas and inhibited by salicylaldoxime or DNP. This hydrogen evolution by M. laminosus is attributed to the action of nitrogenase.

  7. Computer Simulation Study of the Stability Mechanism of Thermophile, MJ0305

    Science.gov (United States)

    Song, Hyundeok; Beck, Thomas

    2011-04-01

    Methanococcus jannaschii (MJ) is a methane-producing thermophile, which was discovered in a 2600m-deep Pacific Ocean vent in 1983. It has the ability to thrive at high temperatures and high pressures, which are unfavorable for most life forms. There have been some experiments to study its stability under extreme conditions, but still the origin of the stability of MJ is not exactly known. MJ0305 is MJ's chloride channel protein. The structure of MJ0305 was built by homology modeling. We compared the stability of MJ0305 with mesophilic Ecoli at 300K, 330K, and 360K by computer simulation to test the effects of temperature. Our results show that high temperatures significantly affect the number of salt bridges and hydrogen bonds. High temperatures decreased the average number of hydrogen bonds for Ecoli and MJ0305. Increased salt bridges at 330K make MJ0305 more stable. Network analysis of MJ0305 showed an increase in the number of hubs at high temperatures. In contrast, the number of hubs of Ecoli was decreased at high temperatures. Calculated network entropy is proportional to the number of hubs. Increased network entropy of MJ0305 at 330K implies increased robustness.

  8. A selection that reports on protein-protein interactions within a thermophilic bacterium.

    Science.gov (United States)

    Nguyen, Peter Q; Silberg, Jonathan J

    2010-07-01

    Many proteins can be split into fragments that exhibit enhanced function upon fusion to interacting proteins. While this strategy has been widely used to create protein-fragment complementation assays (PCAs) for discovering protein-protein interactions within mesophilic organisms, similar assays have not yet been developed for studying natural and engineered protein complexes at the temperatures where thermophilic microbes grow. We describe the development of a selection for protein-protein interactions within Thermus thermophilus that is based upon growth complementation by fragments of Thermotoga neapolitana adenylate kinase (AK(Tn)). Complementation studies with an engineered thermophile (PQN1) that is not viable above 75 degrees C because its adk gene has been replaced by a Geobacillus stearothermophilus ortholog revealed that growth could be restored at 78 degrees C by a vector that coexpresses polypeptides corresponding to residues 1-79 and 80-220 of AK(Tn). In contrast, PQN1 growth was not complemented by AK(Tn) fragments harboring a C156A mutation within the zinc-binding tetracysteine motif unless these fragments were fused to Thermotoga maritima chemotaxis proteins that heterodimerize (CheA and CheY) or homodimerize (CheX). This enhanced complementation is interpreted as arising from chemotaxis protein-protein interactions, since AK(Tn)-C156A fragments having only one polypeptide fused to a chemotaxis protein did not complement PQN1 to the same extent. This selection increases the maximum temperature where a PCA can be used to engineer thermostable protein complexes and to map protein-protein interactions.

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

    Science.gov (United States)

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

    2015-08-15

    A moderately thermophilic consortium was applied in bioleaching multiple metals from contaminated sediment. The consortium got higher acidification and metals soubilization efficiency than that of the pure strains. The synergistic effect of the thermophilic consortium accelerated substrates utilization. The utilization of substrate started with sulfur in the early stage, and then the pH declined, giving rise to making use of the pyrite. Community dynamic showed that A. caldus was the predominant bacteria during the whole bioleaching process while the abundance of S. thermotolerans increased together with pyrite utilization. Solubilization efficiency of Zn, Cu, Mn and Cd reached 98%, 94%, 95%, and 89% respectively, while As, Hg, Pb was only 45%, 34%, 22%. Logistic model was used to simulate the bioleaching process, whose fitting degree was higher than 90%. Correlation analysis revealed that metal leaching was mainly an acid solubilization process. Fraction analysis revealed that metals decreased in mobility and bioavailability. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. [Conversion of acetic acid to methane by thermophiles

    Energy Technology Data Exchange (ETDEWEB)

    Zinder, S.H.

    1993-01-01

    The primary goal of this project is to obtain a better understanding of thermophilic microorganisms which convert acetic acid to CH[sub 4]. The previous funding period represents a departure from earlier research in this laboratory, which was more physiological and ecological. The present work is centered on the biochemistry of the thermophile Methanothrix sp. strain CALS-1. this organism presents a unique opportunity, with its purity and relatively rapid growth, to do comparative biochemical studies with the other major acetotrophic genus Methanosarcina. We previously found that Methanothrix is capable of using acetate at concentrations 100 fold lower than Methanosarcina. This finding suggests that there are significant differences in the pathways of methanogenesis from acetate in the two genera.

  11. 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.

  12. Widespread disulfide bonding in proteins from thermophilic archaea.

    Science.gov (United States)

    Jorda, Julien; Yeates, Todd O

    2011-01-01

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

  13. Gas Fermentation using Thermophilic Moorella Species for production of Biochemicals

    DEFF Research Database (Denmark)

    Redl, Stephanie Maria Anna

    Gas fermentation is a promising technology which gained increasing attention over the last years. In this process, acetogenic bacteria convert gases rich in H2, CO2, and CO, into compounds of higher value. The gas can derive from industrial off-gas or from waste streams via gasification. In the gas...... fermentation processes that are nearly on commercial level, mesophilic acetogens are used to mainly produce ethanol and butanediol. However, thermophilic acetogens, such as Moorella thermoacetica would allow for easy downstream processing when producing volatile products such as acetone. This thesis starts...... with a review of the feedstock potential for gas fermentation and how thermophilic production strains as well as unconventional fermentation processes such as mixotrophy can help to exploit this potential. I analyzed a process with respect to thermodynamic and economic considerations, in which acetone...

  14. Chlorophyll a with a farnesyl tail in thermophilic cyanobacteria.

    Science.gov (United States)

    Wiwczar, Jessica M; LaFountain, Amy M; Wang, Jimin; Frank, Harry A; Brudvig, Gary W

    2017-11-01

    Photosystem II (PSII) of oxygenic photosynthetic organisms normally contains exclusively chlorophyll a (Chl a) as its major light-harvesting pigment. Chl a canonically consists of the chlorin headgroup with a 20-carbon, 4-isoprene unit, phytyl tail. We have examined the 1.9 Å crystal structure of PSII from thermophilic cyanobacteria reported by Shen and coworkers in 2012 (PDB accession of 3ARC/3WU2). A newly refined electron density map from this structure, presented here, reveals that some assignments of the cofactors may be different from those modeled in the 3ARC/3WU2 structure, including a specific Chl a that appears to have a truncated tail by one isoprene unit. We provide experimental evidence using high-performance liquid chromatography and mass spectrometry for a small population of Chl a esterified to a 15-carbon farnesyl tail in PSII of thermophilic cyanobacteria.

  15. Production of Bioethanol From Lignocellulosic Biomass Using Thermophilic Anaerobic Bacteria

    DEFF Research Database (Denmark)

    Georgieva, Tania I.

    2006-01-01

    and xylose and to tolerate the inhibitory compounds present in lignocellulosic hydrolysates is therefore apparent. Several thermophilic anaerobic xylan degrading bacteria from our culture collection (EMB group at BioCentrum-DTU) have been screened for a potential ethanol producer from hemicellulose...... hydrolysates, and out of the screening test, one particular strain (A10) was selected for the best performance. The strain was morphologically and physiologically characterized as Thermoanaerobacter mathranii strain A10. Unlike other thermophilic anaerobic bacteria, the wild-type strain Thermoanaerobacter...... Thermoanaerobacter BG1L1 was further studied. The experiments were carried out in a continuous immobilized reactor system (a fluidized bed reactor), which is likely to be the process design configuration for xylose fermentation in a Danish biorefinery concept for production of fuel ethanol. The immobilization...

  16. Thermophilic anaerobic acetate-utilizing methanogens and their metabolism

    DEFF Research Database (Denmark)

    Mladenovska, Zuzana

    Six strains of thermophilic anaerobic acetate-utilizing methanogens were isolated from different full-scale thermophilic biogas plants in China and Denmark. The strain isolated from the Chinese biogas plant was designated KN-6P and the isolates from the Danish full-scale biogas plants were......, utilizing the substrates acetate, methanol and methylamines but not hydrogen/carbon dioxide. Strain Methanosarcina sp. SO-2P was able to grow mixotrophically on methanol and hydrogen/carbon dioxide with methane formation from hydrogen and carbon dioxide occurring after methanol depletion. All six...... designated HG-1P, LVG-4P R1-1P, SO-2P and V-1P. The isolates were characterized morphologically and physiologically, and their immunological and phylogenetic relatedness to already known isolated strains were established. All isolated strains were identified as organisms belonging to genus Methanosarcina...

  17. Design issues for optimum solar cell configuration

    Science.gov (United States)

    Kumar, Atul; Thakur, Ajay D.

    2018-05-01

    A computer based simulation of solar cell structure is performed to study the optimization of pn junction configuration for photovoltaic action. The fundamental aspects of photovoltaic action viz, absorption, separation collection, and their dependence on material properties and deatails of device structures is discussed. Using SCAPS 1D we have simulated the ideal pn junction and shown the effect of band offset and carrier densities on solar cell performance. The optimum configuration can be achieved by optimizing transport of carriers in pn junction under effect of field dependent recombination (tunneling) and density dependent recombination (SRH, Auger) mechanisms.

  18. Sequential Detection of Thermophilic Lipase and Protease by Zymography.

    Science.gov (United States)

    Kurz, Liliana; Hernández, Zully; Contreras, Lellys M; Wilkesman, Jeff

    2017-01-01

    Lipase and protease present in cell-free fractions of thermophilic Bacillus sp. cultures were analyzed by polyacrylamide gel (PAG) electrophoresis. After run, the gel is electrotransferred to another PAG copolymerized with glycerol tributyrate, olive oil, and gelatin. This multi-substrate gel was incubated first for lipase detection, until bands appeared, and then stained with Coomassie for protease detection. Advantages of this sequential procedure are the detection of two different enzyme activities on a single PAG, beside time and resource saving.

  19. Widespread Disulfide Bonding in Proteins from Thermophilic Archaea

    OpenAIRE

    Jorda, Julien; Yeates, Todd O.

    2011-01-01

    Disulfide bonds are generally not used to stabilize proteins in the cytosolic compartments of bacteria or eukaryotic cells, owing to the chemically reducing nature of those environments. In contrast, certain thermophilic archaea use disulfide bonding as a major mechanism for protein stabilization. Here, we provide a current survey of completely sequenced genomes, applying computational methods to estimate the use of disulfide bonding across the Archaea. Microbes belonging to the Crenarchaea...

  20. Widespread distribution of archaeal reverse gyrase in thermophilic bacteria suggests a complex history of vertical inheritance and lateral gene transfers

    Directory of Open Access Journals (Sweden)

    Céline Brochier-Armanet

    2006-01-01

    Full Text Available Reverse gyrase, an enzyme of uncertain funtion, is present in all hyperthermophilic archaea and bacteria. Previous phylogenetic studies have suggested that the gene for reverse gyrase has an archaeal origin and was transferred laterally (LGT to the ancestors of the two bacterial hyperthermophilic phyla, Thermotogales and Aquificales. Here, we performed an in-depth analysis of the evolutionary history of reverse gyrase in light of genomic progress. We found genes coding for reverse gyrase in the genomes of several thermophilic bacteria that belong to phyla other than Aquificales and Thermotogales. Several of these bacteria are not, strictly speaking, hyperthermophiles because their reported optimal growth temperatures are below 80 °C. Furthermore, we detected a reverse gyrase gene in the sequence of the large plasmid of Thermus thermophilus strain HB8, suggesting a possible mechanism of transfer to the T. thermophilus strain HB8 involving plasmids and transposases. The archaeal part of the reverse gyrase tree is congruent with recent phylogenies of the archaeal domain based on ribosomal proteins or RNA polymerase subunits. Although poorly resolved, the complete reverse gyrase phylogeny suggests an ancient acquisition of the gene by bacteria via one or two LGT events, followed by its secondary distribution by LGT within bacteria. Finally, several genes of archaeal origin located in proximity to the reverse gyrase gene in bacterial genomes have bacterial homologues mostly in thermophiles or hyperthermophiles, raising the possibility that they were co-transferred with the reverse gyrase gene. Our new analysis of the reverse gyrase history strengthens the hypothesis that the acquisition of reverse gyrase may have been a crucial evolutionary step in the adaptation of bacteria to high-temperature environments. However, it also questions the role of this enzyme in thermophilic bacteria and the selective advantage its presence could provide.

  1. Widespread distribution of archaeal reverse gyrase in thermophilic bacteria suggests a complex history of vertical inheritance and lateral gene transfers.

    Science.gov (United States)

    Brochier-Armanet, Céline; Forterre, Patrick

    2007-05-01

    Reverse gyrase, an enzyme of uncertain funtion, is present in all hyperthermophilic archaea and bacteria. Previous phylogenetic studies have suggested that the gene for reverse gyrase has an archaeal origin and was transferred laterally (LGT) to the ancestors of the two bacterial hyperthermophilic phyla, Thermotogales and Aquificales. Here, we performed an in-depth analysis of the evolutionary history of reverse gyrase in light of genomic progress. We found genes coding for reverse gyrase in the genomes of several thermophilic bacteria that belong to phyla other than Aquificales and Thermotogales. Several of these bacteria are not, strictly speaking, hyperthermophiles because their reported optimal growth temperatures are below 80 degrees C. Furthermore, we detected a reverse gyrase gene in the sequence of the large plasmid of Thermus thermophilus strain HB8, suggesting a possible mechanism of transfer to the T. thermophilus strain HB8 involving plasmids and transposases. The archaeal part of the reverse gyrase tree is congruent with recent phylogenies of the archaeal domain based on ribosomal proteins or RNA polymerase subunits. Although poorly resolved, the complete reverse gyrase phylogeny suggests an ancient acquisition of the gene by bacteria via one or two LGT events, followed by its secondary distribution by LGT within bacteria. Finally, several genes of archaeal origin located in proximity to the reverse gyrase gene in bacterial genomes have bacterial homologues mostly in thermophiles or hyperthermophiles, raising the possibility that they were co-transferred with the reverse gyrase gene. Our new analysis of the reverse gyrase history strengthens the hypothesis that the acquisition of reverse gyrase may have been a crucial evolutionary step in the adaptation of bacteria to high-temperature environments. However, it also questions the role of this enzyme in thermophilic bacteria and the selective advantage its presence could provide.

  2. Diversity of thermophiles in a Malaysian hot spring determined using 16S rRNA and shotgun metagenome sequencing

    Directory of Open Access Journals (Sweden)

    Chia Sing eChan

    2015-03-01

    Full Text Available The Sungai Klah (SK hot spring is the second hottest geothermal spring in Malaysia. This hot spring is a shallow, 150-meter-long, fast-flowing stream, with temperatures varying from 50 to 110°C and a pH range of 7.0 to 9.0. Hidden within a wooded area, the SK hot spring is continually fed by plant litter, resulting in a relatively high degree of total organic content (TOC. In this study, a sample taken from the middle of the stream was analyzed at the 16S rRNA V3−V4 region by amplicon metagenome sequencing. Over 35 phyla were detected by analyzing the 16S rRNA data. Firmicutes and Proteobacteria represented approximately 57% of the microbiome. Approximately 70% of the detected thermophiles were strict anaerobes; however, Hydrogenobacter spp., obligate chemolithotrophic thermophiles, represented one of the major taxa. Several thermophilic photosynthetic microorganisms and acidothermophiles were also detected. Most of the phyla identified by 16S rRNA were also found using the shotgun metagenome approaches. The carbon, sulfur, and nitrogen metabolism within the SK hot spring community were evaluated by shotgun metagenome sequencing, and the data revealed diversity in terms of metabolic activity and dynamics. This hot spring has a rich diversified phylogenetic community partly due to its natural environment (plant litter, high TOC, and a shallow stream and geochemical parameters (broad temperature and pH range. It is speculated that symbiotic relationships occur between the members of the community.

  3. Stability of the 'L12 stalk' in ribosomes from mesophilic and (hyper)thermophilic Archaea and Bacteria.

    Science.gov (United States)

    Shcherbakov, D; Dontsova, M; Tribus, M; Garber, M; Piendl, W

    2006-01-01

    The ribosomal stalk complex, consisting of one molecule of L10 and four or six molecules of L12, is attached to 23S rRNA via protein L10. This complex forms the so-called 'L12 stalk' on the 50S ribosomal subunit. Ribosomal protein L11 binds to the same region of 23S rRNA and is located at the base of the 'L12 stalk'. The 'L12 stalk' plays a key role in the interaction of the ribosome with translation factors. In this study stalk complexes from mesophilic and (hyper)thermophilic species of the archaeal genus Methanococcus and from the Archaeon Sulfolobus solfataricus, as well as from the Bacteria Escherichia coli, Geobacillus stearothermophilus and Thermus thermophilus, were overproduced in E.coli and purified under non-denaturing conditions. Using filter-binding assays the affinities of the archaeal and bacterial complexes to their specific 23S rRNA target site were analyzed at different pH, ionic strength and temperature. Affinities of both archaeal and bacterial complexes for 23S rRNA vary by more than two orders of magnitude, correlating very well with the growth temperatures of the organisms. A cooperative effect of binding to 23S rRNA of protein L11 and the L10/L12(4) complex from mesophilic and thermophilic Archaea was shown to be temperature-dependent.

  4. Genetic Tools and Techniques for Recombinant Expression in Thermophilic Bacillaceae

    Directory of Open Access Journals (Sweden)

    Eivind B. Drejer

    2018-05-01

    Full Text Available Although Escherichia coli and Bacillus subtilis are the most prominent bacterial hosts for recombinant protein production by far, additional species are being explored as alternatives for production of difficult-to-express proteins. In particular, for thermostable proteins, there is a need for hosts able to properly synthesize, fold, and excrete these in high yields, and thermophilic Bacillaceae represent one potentially interesting group of microorganisms for such purposes. A number of thermophilic Bacillaceae including B. methanolicus, B. coagulans, B. smithii, B. licheniformis, Geobacillus thermoglucosidasius, G. kaustophilus, and G. stearothermophilus are investigated concerning physiology, genomics, genetic tools, and technologies, altogether paving the way for their utilization as hosts for recombinant production of thermostable and other difficult-to-express proteins. Moreover, recent successful deployments of CRISPR/Cas9 in several of these species have accelerated the progress in their metabolic engineering, which should increase their attractiveness for future industrial-scale production of proteins. This review describes the biology of thermophilic Bacillaceae and in particular focuses on genetic tools and methods enabling use of these organisms as hosts for recombinant protein production.

  5. REGARDING "TRAGIC ECONOMIC OPTIMUM" FROM HOLISTIC+ PERSPECTIVE

    Directory of Open Access Journals (Sweden)

    Constantin Popescu

    2010-12-01

    Full Text Available Communication aims to discuss the new scientific vision of "the entire integrated" as it follows the recent achievements of quantum physics, psychology and biology. From this perspective, economy is seen as a living organism, part of the social organism and together with de bright ecology. The optimum of the economy as a living organism is based on dynamic compatibilities with all common living requirements. The evolution of economic life is organically linked to the unavoidable circumstances contained in the form of V. Frankl ‘s tragic triad consisting of: pain, guilt and death. In interaction with the holistic triad circumscribed by limitations, uncertainties and open interdependencies, the tragic economic optimum (TEO is formed. It can be understood as that state of economic life in which freedom of choice of scarce resources under uncertainty has in the compatibility of rationality and hope the development criteria of MEANING. TEO means to say YES to economic life even in conditions of resource limitations, bankruptcies and unemployment, negative externalities, stress, etc. By respiritualization of responsibility using scientific knowledge. TEO - involves multicriteria modeling of economic life by integrating human demands, community, environmental, spiritual and business development in the assessment predicting human GDP as a variable wave aggregate.

  6. Optimum body size of Holstein replacement heifers.

    Science.gov (United States)

    Hoffman, P C

    1997-03-01

    Criteria that define optimum body size of replacement heifers are required by commercial dairy producers to evaluate replacement heifer management programs. Historically recommended body size criteria have been based on live BW measurements. Numerous research studies have observed a positive relationship between BW at first calving and first lactation milk yield, which has served as the impetus for using live BW to define body size of replacement heifers. Live BW is, however, not the only available measurement to define body size. Skeletal measurements such as wither height, length, and pelvic area have been demonstrated to be related to first lactation performance and (or) dystocia. Live BW measurements also do not define differences in body composition. Differences in body composition of replacement heifers at first calving are also related to key performance variables. An updated research data base is available for the modern Holstein genotype to incorporate measures of skeletal growth and body composition with BW when defining body size. These research projects also lend insight into the relative importance of measurements that define body size of replacement heifers. Incorporation of these measurements from current research into present BW recommendations should aid commercial dairy producers to better define replacement heifer growth and management practices. This article proposes enhancements in defining optimum body size and growth characteristics of Holstein replacement heifers.

  7. Insight into glycoside hydrolases for debranched xylan degradation from extremely thermophilic bacterium Caldicellulosiruptor lactoaceticus.

    Directory of Open Access Journals (Sweden)

    Xiaojing Jia

    Full Text Available Caldicellulosiruptor lactoaceticus 6A, an anaerobic and extremely thermophilic bacterium, uses natural xylan as carbon source. The encoded genes of C. lactoaceticus 6A for glycoside hydrolase (GH provide a platform for xylan degradation. The GH family 10 xylanase (Xyn10A and GH67 α-glucuronidase (Agu67A from C. lactoaceticus 6A were heterologously expressed, purified and characterized. Both Xyn10A and Agu67A are predicted as intracellular enzymes as no signal peptides identified. Xyn10A and Agu67A had molecular weight of 47.0 kDa and 80.0 kDa respectively as determined by SDS-PAGE, while both appeared as homodimer when analyzed by gel filtration. Xyn10A displayed the highest activity at 80 °C and pH 6.5, as 75 °C and pH 6.5 for Agu67A. Xyn10A had good stability at 75 °C, 80 °C, and pH 4.5-8.5, respectively, and was sensitive to various metal ions and reagents. Xyn10A possessed hydrolytic activity towards xylo-oligosaccharides (XOs and beechwood xylan. At optimum conditions, the specific activity of Xyn10A was 44.6 IU/mg with beechwood xylan as substrate, and liberated branched XOs, xylobiose, and xylose. Agu67A was active on branched XOs with methyl-glucuronic acids (MeGlcA sub-chains, and primarily generated XOs equivalents and MeGlcA. The specific activity of Agu67A was 1.3 IU/mg with aldobiouronic acid as substrate. The synergistic action of Xyn10A and Agu67A was observed with MeGlcA branched XOs and xylan as substrates, both backbone and branched chain of substrates were degraded, and liberated xylose, xylobiose, and MeGlcA. The synergism of Xyn10A and Agu67A provided not only a thermophilic method for natural xylan degradation, but also insight into the mechanisms for xylan utilization of C. lactoaceticus.

  8. Nitrogen and Oxygen Isotope Effects of Ammonia Oxidation by Thermophilic Thaumarchaeota from a Geothermal Water Stream.

    Science.gov (United States)

    Nishizawa, Manabu; Sakai, Sanae; Konno, Uta; Nakahara, Nozomi; Takaki, Yoshihiro; Saito, Yumi; Imachi, Hiroyuki; Tasumi, Eiji; Makabe, Akiko; Koba, Keisuke; Takai, Ken

    2016-08-01

    Ammonia oxidation regulates the balance of reduced and oxidized nitrogen pools in nature. Although ammonia-oxidizing archaea have been recently recognized to often outnumber ammonia-oxidizing bacteria in various environments, the contribution of ammonia-oxidizing archaea is still uncertain due to difficulties in the in situ quantification of ammonia oxidation activity. Nitrogen and oxygen isotope ratios of nitrite (δ(15)NNO2- and δ(18)ONO2-, respectively) are geochemical tracers for evaluating the sources and the in situ rate of nitrite turnover determined from the activities of nitrification and denitrification; however, the isotope ratios of nitrite from archaeal ammonia oxidation have been characterized only for a few marine species. We first report the isotope effects of ammonia oxidation at 70°C by thermophilic Thaumarchaeota populations composed almost entirely of "Candidatus Nitrosocaldus." The nitrogen isotope effect of ammonia oxidation varied with ambient pH (25‰ to 32‰) and strongly suggests the oxidation of ammonia, not ammonium. The δ(18)O value of nitrite produced from ammonia oxidation varied with the δ(18)O value of water in the medium but was lower than the isotopic equilibrium value in water. Because experiments have shown that the half-life of abiotic oxygen isotope exchange between nitrite and water is longer than 33 h at 70°C and pH ≥6.6, the rate of ammonia oxidation by thermophilic Thaumarchaeota could be estimated using δ(18)ONO2- in geothermal environments, where the biological nitrite turnover is likely faster than 33 h. This study extended the range of application of nitrite isotopes as a geochemical clock of the ammonia oxidation activity to high-temperature environments. Because ammonia oxidation is generally the rate-limiting step in nitrification that regulates the balance of reduced and oxidized nitrogen pools in nature, it is important to understand the biological and environmental factors underlying the regulation of

  9. Hydrophobic environment is a key factor for the stability of thermophilic proteins.

    Science.gov (United States)

    Gromiha, M Michael; Pathak, Manish C; Saraboji, Kadhirvel; Ortlund, Eric A; Gaucher, Eric A

    2013-04-01

    The stability of thermophilic proteins has been viewed from different perspectives and there is yet no unified principle to understand this stability. It would be valuable to reveal the most important interactions for designing thermostable proteins for such applications as industrial protein engineering. In this work, we have systematically analyzed the importance of various interactions by computing different parameters such as surrounding hydrophobicity, inter-residue interactions, ion-pairs and hydrogen bonds. The importance of each interaction has been determined by its predicted relative contribution in thermophiles versus the same contribution in mesophilic homologues based on a dataset of 373 protein families. We predict that hydrophobic environment is the major factor for the stability of thermophilic proteins and found that 80% of thermophilic proteins analyzed showed higher hydrophobicity than their mesophilic counterparts. Ion pairs, hydrogen bonds, and interaction energy are also important and favored in 68%, 50%, and 62% of thermophilic proteins, respectively. Interestingly, thermophilic proteins with decreased hydrophobic environments display a greater number of hydrogen bonds and/or ion pairs. The systematic elimination of mesophilic proteins based on surrounding hydrophobicity, interaction energy, and ion pairs/hydrogen bonds, led to correctly identifying 95% of the thermophilic proteins in our analyses. Our analysis was also applied to another, more refined set of 102 thermophilic-mesophilic pairs, which again identified hydrophobicity as a dominant property in 71% of the thermophilic proteins. Further, the notion of surrounding hydrophobicity, which characterizes the hydrophobic behavior of residues in a protein environment, has been applied to the three-dimensional structures of elongation factor-Tu proteins and we found that the thermophilic proteins are enriched with a hydrophobic environment. The results obtained in this work highlight the

  10. Characterization Of A Novel Hydrolytic Enzyme Producing Thermophilic Bacterium Isolated From The Hot Spring Of Azad Kashmir-Pakistan

    Directory of Open Access Journals (Sweden)

    Sana Zahoor

    Full Text Available ABSTRACT A thermophilic bacterium (TP-2 was isolated from the Tatta Pani hot spring in Azad Kashmir and was characterized using phenotypic and genotypic characters. The strain developed cream colored, round, smooth, flat and slimy colonies while the cells were Gram positive rods that ranged in size from about 2.1-3.6 μm to 0.2-0.3 μm in width. Sequence analysis of its 16S rRNA gene showed that isolate TP-2 had 89% homology with Geobacillus debilis. It grew within pH range of 5.5 to 8.5 with optimum growth at pH 7.0. The isolate showed optimum growth at 65ºC and gave positive results for gelatin hydrolysis (GEL, ortho nitrophenyl-β-D-galactopyranosidase (ONPG, and nitrate production and produced acid from sucrose, glucose and maltose. It utilized glucose, fructose, maltose, lactose, sucrose, xylan, starch, filter paper and carboxymethylcellulose as sole carbon source. Isolate TP-2 produced significant amount of industrially important enzymes i.e. extracellular α-amylase, CMCase, FPase, Xylanase, Protease and Lipase and intracellular CMCase and FPase.

  11. Thermoactinomyces guangxiensis sp. nov., a thermophilic actinomycete isolated from mushroom compost.

    Science.gov (United States)

    Wu, Hao; Liu, Bin; Pan, Shangli

    2015-09-01

    A novel thermophilic actinomycete, designated strain CD-1(T), was isolated from mushroom compost in Nanning, Guangxi province, China. The strain grew at 37-55 °C (optimum 45-50 °C), pH 6.0-11.0 (optimum pH 7.0-9.0) and with 0-2.0% NaCl (optimum 0-1.0%), formed well-developed white aerial mycelium and pale-yellow vegetative mycelium, and single endospores (0.8-1.0 μm diameter) were borne on long sporophores (2-3 μm length). The endospores were spherical-polyhedron in shape with smooth surface. Based on its phenotypic and phylogenetic characteristics, strain CD-1(T) is affiliated to the genus Thermoactinomyces. It contained meso-diaminopimelic acid as the diagnostic diamino acid; the whole-cell sugars were ribose and glucose. Major fatty acids were iso-C15 :  0, C16 : 0, anteiso-C15  : 0 and iso-C17  : 0. MK-7 was the predominant menaquinone. The polar phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylethanolamine containing hydroxylated fatty acids, ninhydrin-positive glycophospholipid, an unknown phospholipid and glycolipids. The G+C content of the genomic DNA was 48.8%. 16S rRNA gene sequence analysis showed that the organism was closely related to Lihuaxuella thermophila YIM 77831(T) (95.69% sequence similarity), Thermoactinomyces daqus H-18(T) (95.49%), Laceyella putida KCTC 3666(T) (95.05%), Thermoactinomyces vulgaris KCTC 9076(T) (95.01%) and Thermoactinomyces intermedius JCM 3312(T) (94.55%). Levels of DNA-DNA relatedness between strain CD-1T and Lihuaxuella thermophila JCM 18059(T), Thermoactinomyces daqus DSM 45914(T), Laceyella putida JCM 8091(T), Thermoactinomyces vulgaris JCM 3162(T) and Thermoactinomyces intermedius JCM 3312(T) were low (22.8, 33.3, 24.7, 29.4 and 30.0%, respectively). A battery of phenotypic, genotypic and DNA-DNA relatedness data indicated that strain CD-1T represented a novel species of the genus Thermoactinomyces, for which the name Thermoactinomyces guangxiensis sp. nov

  12. DETERMINATION of OPTIMUM CONDITION of PAPAIN ENZYME FROM PAPAYA VAR JAVA (Carica papaya

    Directory of Open Access Journals (Sweden)

    Aline Puspita Kusumadjaja

    2010-06-01

    Full Text Available A study to investigate the optimum condition of papain enzyme has been carried out. The condition that are investigated are pH and temperature, based on measurement of enzyme activity which is defined as mmole tyrosin that are released in reaction between papain enzyme and casein as substrat per minute. In this research, the papain enzyme was isolated from pepaya burung varietas Java. The enzyme was partially purified by precipitation method using 30% - 50% saturated acetone. The result showed that the optimum conditions of papain enzyme are in pH 6 with activity 2,606 U/mL, and temperature at 50 oC with activity 2,469 U/mL. Keywords : Papaya var Java, papain, optimum condition, enzymatic activity

  13. Anaerobic digestion of the vinasses from the fermentation of Agave tequilana Weber to tequila: The effect of pH, temperature and hydraulic retention time on the production of hydrogen and methane

    Energy Technology Data Exchange (ETDEWEB)

    Espinoza-Escalante, Froylan M.; Pelayo-Ortiz, Carlos; Navarro-Corona, Jose; Gonzalez-Garcia, Yolanda [Department of Chemical Engineering, University of Guadalajara, Blvd. M. Garcia Barragan No. 1421, Guadalajara CP 44430 (Mexico); Bories, Andre [INRA-Unite Experimentale de Pech-Rouge, 11430 Gruissan (France); Gutierrez-Pulido, Humberto [Department of Mathematics, University of Guadalajara, Blvd. M. Garcia Barragan No. 1421, Guadalajara CP 44430 (Mexico)

    2009-01-15

    The objective of this work was to study the effect of three operational parameters (pH, hydraulic retention time (HRT) and growing temperature) on a semi-continuous bioreactor treating Tequila's vinasses by anaerobic digestion (AD). The response was measured through four response variables: total reducing sugars (TRS) consumption, VFA's, hydrogen and methane production. Trials were done according to a factorial design. The experimental results were studied through a multiple response optimization (MRO) analysis to find single and multiple optimums for the above-mentioned variables. Mathematical models that can describe the effect of the operational parameters on each response variable were found. In this study it is shown that hydrogen production is favored at thermophilic growth (55 C), operating the reactor at a slight acidic pH range and at the higher HRT in the boundaries of the experimental region. (author)

  14. Anaerobic digestion of the vinasses from the fermentation of Agave tequilana Weber to tequila: The effect of pH, temperature and hydraulic retention time on the production of hydrogen and methane

    International Nuclear Information System (INIS)

    Espinoza-Escalante, Froylan M.; Pelayo-Ortiz, Carlos; Navarro-Corona, Jose; Gonzalez-Garcia, Yolanda; Bories, Andre; Gutierrez-Pulido, Humberto

    2009-01-01

    The objective of this work was to study the effect of three operational parameters (pH, hydraulic retention time (HRT) and growing temperature) on a semi-continuous bioreactor treating Tequila's vinasses by anaerobic digestion (AD). The response was measured through four response variables: total reducing sugars (TRS) consumption, VFA's, hydrogen and methane production. Trials were done according to a factorial design. The experimental results were studied through a multiple response optimization (MRO) analysis to find single and multiple optimums for the above-mentioned variables. Mathematical models that can describe the effect of the operational parameters on each response variable were found. In this study it is shown that hydrogen production is favored at thermophilic growth (55 deg. C), operating the reactor at a slight acidic pH range and at the higher HRT in the boundaries of the experimental region

  15. Structural prediction and comparative docking studies of psychrophilic β- Galactosidase with lactose, ONPG and PNPG against its counter parts of mesophilic and thermophilic enzymes.

    Science.gov (United States)

    Kumar, Ponnada Suresh; Pulicherla, Kk; Ghosh, Mrinmoy; Kumar, Anmol; Rao, Krs Sambasiva

    2011-01-01

    Enzymes from psychrophiles catalyze the reactions at low temperatures with higher specific activity. Among all the psychrophilic enzymes produced, cold active β-galactosidase from marine psychrophiles revalorizes a new arena in numerous areas at industrial level. The hydrolysis of lactose in to glucose and galactose by cold active β-galactosidase offers a new promising approach in removal of lactose from milk to overcome the problem of lactose intolerance. Herein we propose, a 3D structure of cold active β-galactosidase enzyme sourced from Pseudoalteromonas haloplanktis by using Modeler 9v8 and best model was developed having 88% of favourable region in ramachandran plot. Modelling was followed by docking studies with the help of Auto dock 4.0 against the three substrates lactose, ONPG and PNPG. In addition, comparative docking studies were also performed for the 3D model of psychrophilic β-galactosidase with mesophilic and thermophilic enzymes. Docking studies revealed that binding affinity of enzyme towards the three different substrates is more for psychrophilic enzyme when compared with mesophilic and thermophilic enzymes. It indicates that the enzyme has high specific activity at low temperature when compared with mesophilic and thermophilic enzymes.

  16. Optimum conditions for aging of stainless maraging steels

    International Nuclear Information System (INIS)

    Mironenko, P.A.; Krasnikova, S.I.; Drobot, A.V.

    1980-01-01

    Aging kinetics of two 0Kh11N10M2T type steels in which 3 % Mo (steel 1), and 3 % Mo and 11 % Co (steel 2) had been additionally introduced instead of titanium were investigated. Electron microscopy and X-ray methods were used. It was ascertained that the process of steel aging proceeded in 3 stages. Steel 2 was hardened more intensively during the aging, had a higher degree of hardness and strength after the aging, weakened more slowly if overaged than steel 1. The intermetallide hcp-phase Fe 2 Mo was the hardening phase on steels extended aging. Optimum combination of impact strength and strength was was achieved using two-stage aging: the first stage - maximum strength aging was achieved, the second stage - aging at minimum temperatures of two-phase α+γ region

  17. Alcohol Selectivity in a Synthetic Thermophilic n-Butanol Pathway Is Driven by Biocatalytic and Thermostability Characteristics of Constituent Enzymes.

    Science.gov (United States)

    Loder, Andrew J; Zeldes, Benjamin M; Garrison, G Dale; Lipscomb, Gina L; Adams, Michael W W; Kelly, Robert M

    2015-10-01

    n-Butanol is generated as a natural product of metabolism by several microorganisms, but almost all grow at mesophilic temperatures. A synthetic pathway for n-butanol production from acetyl coenzyme A (acetyl-CoA) that functioned at 70°C was assembled in vitro from enzymes recruited from thermophilic bacteria to inform efforts for engineering butanol production into thermophilic hosts. Recombinant versions of eight thermophilic enzymes (β-ketothiolase [Thl], 3-hydroxybutyryl-CoA dehydrogenase [Hbd], and 3-hydroxybutyryl-CoA dehydratase [Crt] from Caldanaerobacter subterraneus subsp. tengcongensis; trans-2-enoyl-CoA reductase [Ter] from Spirochaeta thermophila; bifunctional acetaldehyde dehydrogenase/alcohol dehydrogenase [AdhE] from Clostridium thermocellum; and AdhE, aldehyde dehydrogenase [Bad], and butanol dehydrogenase [Bdh] from Thermoanaerobacter sp. strain X514) were utilized to examine three possible pathways for n-butanol. These pathways differed in the two steps required to convert butyryl-CoA to n-butanol: Thl-Hbd-Crt-Ter-AdhE (C. thermocellum), Thl-Hbd-Crt-Ter-AdhE (Thermoanaerobacter X514), and Thl-Hbd-Crt-Ter-Bad-Bdh. n-Butanol was produced at 70°C, but with different amounts of ethanol as a coproduct, because of the broad substrate specificities of AdhE, Bad, and Bdh. A reaction kinetics model, validated via comparison to in vitro experiments, was used to determine relative enzyme ratios needed to maximize n-butanol production. By using large relative amounts of Thl and Hbd and small amounts of Bad and Bdh, >70% conversion to n-butanol was observed in vitro, but with a 60% decrease in the predicted pathway flux. With more-selective hypothetical versions of Bad and Bdh, >70% conversion to n-butanol is predicted, with a 19% increase in pathway flux. Thus, more-selective thermophilic versions of Bad, Bdh, and AdhE are needed to fully exploit biocatalytic n-butanol production at elevated temperatures. Copyright © 2015, American Society for

  18. In vivo and in vitro protein imaging in thermophilic archaea by exploiting a novel protein tag.

    Science.gov (United States)

    Visone, Valeria; Han, Wenyuan; Perugino, Giuseppe; Del Monaco, Giovanni; She, Qunxin; Rossi, Mosè; Valenti, Anna; Ciaramella, Maria

    2017-01-01

    Protein imaging, allowing a wide variety of biological studies both in vitro and in vivo, is of great importance in modern biology. Protein and peptide tags fused to proteins of interest provide the opportunity to elucidate protein location and functions, detect protein-protein interactions, and measure protein activity and kinetics in living cells. Whereas several tags are suitable for protein imaging in mesophilic organisms, the application of this approach to microorganisms living at high temperature has lagged behind. Archaea provide an excellent and unique model for understanding basic cell biology mechanisms. Here, we present the development of a toolkit for protein imaging in the hyperthermophilic archaeon Sulfolobus islandicus. The system relies on a thermostable protein tag (H5) constructed by engineering the alkylguanine-DNA-alkyl-transferase protein of Sulfolobus solfataricus, which can be covalently labeled using a wide range of small molecules. As a suitable host, we constructed, by CRISPR-based genome-editing technology, a S. islandicus mutant strain deleted for the alkylguanine-DNA-alkyl-transferase gene (Δogt). Introduction of a plasmid-borne H5 gene in this strain led to production of a functional H5 protein, which was successfully labeled with appropriate fluorescent molecules and visualized in cell extracts as well as in Δogt live cells. H5 was fused to reverse gyrase, a peculiar thermophile-specific DNA topoisomerase endowed with positive supercoiling activity, and allowed visualization of the enzyme in living cells. To the best of our knowledge, this is the first report of in vivo imaging of any protein of a thermophilic archaeon, filling an important gap in available tools for cell biology studies in these organisms.

  19. Design chart of optimum current leads

    International Nuclear Information System (INIS)

    Ishibashi, K.; Katase, A.; Maechata, K.

    1986-01-01

    The heat flow through current leads is one of major heat losses in a superconducting magnet system. To reduce the heat flow, current leads have been optimized in a complex way by varying such quantities as conductor length, cross-sectional area, heat transfer coefficient and cooling perimeter. Therefore, this study is made to simplify the design procedure, and to explain the general characteristics of the current leads. A new combined parameter which takes turbulent flow into account is introduced in the present work to enable us to draw a useful design chart. This chart gives, to a wide variety of current leads, detailed information about the optimum design-viz. geometric dimensions, heat flow into liquid helium, and pressure drop of the cooling gas. Change of the cross-sectional area along the conductor may improve the current lead performance. The effects of this area change are examined in detail

  20. Optimum Maintenance Strategies for Highway Bridges

    DEFF Research Database (Denmark)

    Frangopol, Dan M.; Thoft-Christensen, Palle; Das, Parag C.

    As bridges become older and maintenance costs become higher, transportation agencies are facing challenges related to implementation of optimal bridge management programs based on life cycle cost considerations. A reliability-based approach is necessary to find optimal solutions based on minimum...... expected life-cycle costs or maximum life-cycle benefits. This is because many maintenance activities can be associated with significant costs, but their effects on bridge safety can be minor. In this paper, the program of an investigation on optimum maintenance strategies for different bridge types...... is described. The end result of this investigation will be a general reliability-based framework to be used by the UK Highways Agency in order to plan optimal strategies for the maintenance of its bridge network so as to optimize whole-life costs....

  1. Optimum design of a nuclear heat supply

    International Nuclear Information System (INIS)

    Borel, J.P.

    1984-01-01

    This paper presents an economic analysis for the optimum design of a nuclear heat supply to a given district-heating network. First, a general description of the system is given, which includes a nuclear power plant, a heating power plant and a district-heating network. The heating power plant is fed with steam from the nuclear power plant. It is assumed that the heating network is already in operation and that the nuclear power plant was previously designed to supply electricity. Second, a technical definition of the heat production and transportation installations is given. The optimal power of these installations is examined. The main result is a relationship between the network capacity and the level of the nuclear heat supply as a substitute for oil under the best economic conditions. The analysis also presents information for choosing the best operating mode. Finally, the heating power plant is studied in more detail from the energy, technical and economic aspects. (author)

  2. Optimum utilisation of the uranium resource

    International Nuclear Information System (INIS)

    Ion, S. E.; Wilson, P.D.

    1998-01-01

    The nuclear industry faces many challenges, notably to maximise safety, secure an adequate energy supply, manage wastes satisfactorily and achieve political acceptability. One way forward is to optimise together the various interdependent stages of the fuel cycle - the now familiar 'holistic approach'. Many of the issues will demand large R and D expenditure, most effectively met through international collaboration. Sustainable development requires optimum utilisation of energy potential, to which the most accessible key is recycling uranium and the plutonium bred from it. Realising anything like this full potential requires fast-neutron reactors, and therefore BNFL continues to sustain the UK involvement in their international development. Meanwhile, current R and D programmes must aim to make the nuclear option more competitive against fossil resources, while maintaining and developing the necessary skills for more advanced technologies The paper outlines the strategies being pursued and highlights BNFL 's programmes. (author)

  3. Methanomethylovorans thermophila sp. nov., a thermophilic, methylotrophic methanogen form an anaerobic reactor fed with methanol

    NARCIS (Netherlands)

    Jiang, B.; Parshina, S.N.; Doesburg, van W.C.J.; Lomans, B.P.; Stams, A.J.M.

    2005-01-01

    A novel thermophilic, obligately methylotrophic, methanogenic archaeon, strain L2FAWT, was isolated from a thermophilic laboratory-scale upflow anaerobic sludge blanket reactor fed with methanol as the carbon and energy source. Cells of strain L2FAWT were non-motile, irregular cocci, 0·7¿1·5 µm in

  4. Supplement to thermophilic hydrolysis of liquid manures. Bilag til termofil hydrolyse af gylle

    Energy Technology Data Exchange (ETDEWEB)

    1990-07-01

    A supplement to ''Thermophilic hydrolysis of liquid manures'' which contains descriptions of testing methods and results for determining the influence of additives such as propionic acid or triolein on chemical reactions in connection with the decomposition of liquid manures under thermophilic conditions. (AB).

  5. Efficient Genome Editing of a Facultative Thermophile Using Mesophilic spCas9

    NARCIS (Netherlands)

    Mougiakos, Ioannis; Bosma, Elleke F.; Weenink, Koen; Vossen, Eric; Goijvaerts, Kirsten; Oost, van der John; Kranenburg, van Richard

    2017-01-01

    Well-developed genetic tools for thermophilic microorganisms are scarce, despite their industrial and scientific relevance. Whereas highly efficient CRISPR/Cas9-based genome editing is on the rise in prokaryotes, it has never been employed in a thermophile. Here, we apply Streptococcus pyogenes

  6. Developing an Optimum Protocol for Thermoluminescence Dosimetry with GR-200 Chips using Taguchi Method.

    Science.gov (United States)

    Sadeghi, Maryam; Faghihi, Reza; Sina, Sedigheh

    2017-06-15

    Thermoluminescence dosimetry (TLD) is a powerful technique with wide applications in personal, environmental and clinical dosimetry. The optimum annealing, storage and reading protocols are very effective in accuracy of TLD response. The purpose of this study is to obtain an optimum protocol for GR-200; LiF: Mg, Cu, P, by optimizing the effective parameters, to increase the reliability of the TLD response using Taguchi method. Taguchi method has been used in this study for optimization of annealing, storage and reading protocols of the TLDs. A number of 108 GR-200 chips were divided into 27 groups, each containing four chips. The TLDs were exposed to three different doses, and stored, annealed and read out by different procedures as suggested by Taguchi Method. By comparing the signal-to-noise ratios the optimum dosimetry procedure was obtained. According to the results, the optimum values for annealing temperature (°C), Annealing Time (s), Annealing to Exposure time (d), Exposure to Readout time (d), Pre-heat Temperature (°C), Pre-heat Time (s), Heating Rate (°C/s), Maximum Temperature of Readout (°C), readout time (s) and Storage Temperature (°C) are 240, 90, 1, 2, 50, 0, 15, 240, 13 and -20, respectively. Using the optimum protocol, an efficient glow curve with low residual signals can be achieved. Using optimum protocol obtained by Taguchi method, the dosimetry can be effectively performed with great accuracy. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  7. Thermophilic Fungi to Dominate Aflatoxigenic/Mycotoxigenic Fungi on Food under Global Warming.

    Science.gov (United States)

    Paterson, Robert Russell M; Lima, Nelson

    2017-02-17

    Certain filamentous fungi produce mycotoxins that contaminate food. Mycotoxin contamination of crops is highly influenced by environmental conditions and is already affected by global warming, where there is a succession of mycotoxigenic fungi towards those that have higher optimal growth temperatures. Aflatoxigenic fungi are at the highest limit of temperature although predicted increases in temperature are beyond that constraint. The present paper discusses what will succeed these fungi and represents the first such consideration. Aflatoxins are the most important mycotoxins and are common in tropical produce, much of which is exported to temperate regions. Hot countries may produce safer food under climate change because aflatoxigenic fungi will be inhibited. The same situation will occur in previously temperate regions where these fungi have recently appeared, although decades later. Existing thermotolerant and thermophilic fungi (TTF) will dominate, in contrast to the conventional mycotoxigenic fungi adapting or mutating, as it will be quicker. TTF produce a range of secondary metabolites, or potential mycotoxins and patulin which may become a new threat. In addition, Aspergillus fumigatus will appear more frequently, a serious human pathogen, because it is (a) thermotolerant and (b) present on crops: hence this is an even greater problem. An incubation temperature of 41 °C needs employing forthwith to detect TTF. Finally, TTF in crops requires study because of the potential for diseases in humans and animals under climate change.

  8. Thermophilic Fungi to Dominate Aflatoxigenic/Mycotoxigenic Fungi on Food under Global Warming

    Directory of Open Access Journals (Sweden)

    Robert Russell M. Paterson

    2017-02-01

    Full Text Available Certain filamentous fungi produce mycotoxins that contaminate food. Mycotoxin contamination of crops is highly influenced by environmental conditions and is already affected by global warming, where there is a succession of mycotoxigenic fungi towards those that have higher optimal growth temperatures. Aflatoxigenic fungi are at the highest limit of temperature although predicted increases in temperature are beyond that constraint. The present paper discusses what will succeed these fungi and represents the first such consideration. Aflatoxins are the most important mycotoxins and are common in tropical produce, much of which is exported to temperate regions. Hot countries may produce safer food under climate change because aflatoxigenic fungi will be inhibited. The same situation will occur in previously temperate regions where these fungi have recently appeared, although decades later. Existing thermotolerant and thermophilic fungi (TTF will dominate, in contrast to the conventional mycotoxigenic fungi adapting or mutating, as it will be quicker. TTF produce a range of secondary metabolites, or potential mycotoxins and patulin which may become a new threat. In addition, Aspergillus fumigatus will appear more frequently, a serious human pathogen, because it is (a thermotolerant and (b present on crops: hence this is an even greater problem. An incubation temperature of 41 °C needs employing forthwith to detect TTF. Finally, TTF in crops requires study because of the potential for diseases in humans and animals under climate change.

  9. Complete genome of the cellyloytic thermophile Acidothermus cellulolyticus 11B provides insights into its ecophysiological and evloutionary adaptations

    Energy Technology Data Exchange (ETDEWEB)

    Barabote, Ravi D.; Xie, Gary; Leu, David H.; Normand, Philippe; Necsulea, Anamaria; Daubin, Vincent; Medigue, Claudine; Adney, William S.; Xu,Xin Clare; Lapidus, Alla; Detter, Chris; Pujic, Petar; Bruce, David; Lavire, Celine; Challacombe, Jean F.; Brettin, Thomas S.; Berry, Alison M.

    2009-01-01

    We present here the complete 2.4 Mb genome of the cellulolytic actinobacterial thermophile, Acidothermus cellulolyticus 11B. New secreted glycoside hydrolases and carbohydrate esterases were identified in the genome, revealing a diverse biomass-degrading enzyme repertoire far greater than previously characterized, and significantly elevating the industrial value of this organism. A sizable fraction of these hydrolytic enzymes break down plant cell walls and the remaining either degrade components in fungal cell walls or metabolize storage carbohydrates such as glycogen and trehalose, implicating the relative importance of these different carbon sources. A novel feature of the A. cellulolyticus secreted cellulolytic and xylanolytic enzymes is that they are fused to multiple tandemly arranged carbohydrate binding modules (CBM), from families 2 and 3. Interestingly, CBM3 was found to be always N-terminal to CBM2, suggesting a functional constraint driving this organization. While the catalytic domains of these modular enzymes are either diverse or unrelated, the CBMs were found to be highly conserved in sequence and may suggest selective substrate-binding interactions. For the most part, thermophilic patterns in the genome and proteome of A. cellulolyticus were weak, which may be reflective of the recent evolutionary history of A. cellulolyticus since its divergence from its closest phylogenetic neighbor Frankia, a mesophilic plant endosymbiont and soil dweller. However, ribosomal proteins and non-coding RNAs (rRNA and tRNAs) in A. cellulolyticus showed thermophilic traits suggesting the importance of adaptation of cellular translational machinery to environmental temperature. Elevated occurrence of IVYWREL amino acids in A. cellulolyticus orthologs compared to mesophiles, and inverse preferences for G and A at the first and third codon positions also point to its ongoing thermoadaptation. Additional interesting features in the genome of this cellulolytic, hot

  10. Complete genome of the cellulolytic thermophile Acidothermus cellulolyticus 11B provides insights into its ecophysiological and evolutionary adaptations

    Science.gov (United States)

    Barabote, Ravi D.; Xie, Gary; Leu, David H.; Normand, Philippe; Necsulea, Anamaria; Daubin, Vincent; Médigue, Claudine; Adney, William S.; Xu, Xin Clare; Lapidus, Alla; Parales, Rebecca E.; Detter, Chris; Pujic, Petar; Bruce, David; Lavire, Celine; Challacombe, Jean F.; Brettin, Thomas S.; Berry, Alison M.

    2009-01-01

    We present here the complete 2.4-Mb genome of the cellulolytic actinobacterial thermophile Acidothermus cellulolyticus 11B. New secreted glycoside hydrolases and carbohydrate esterases were identified in the genome, revealing a diverse biomass-degrading enzyme repertoire far greater than previously characterized and elevating the industrial value of this organism. A sizable fraction of these hydrolytic enzymes break down plant cell walls, and the remaining either degrade components in fungal cell walls or metabolize storage carbohydrates such as glycogen and trehalose, implicating the relative importance of these different carbon sources. Several of the A. cellulolyticus secreted cellulolytic and xylanolytic enzymes are fused to multiple tandemly arranged carbohydrate binding modules (CBM), from families 2 and 3. For the most part, thermophilic patterns in the genome and proteome of A. cellulolyticus were weak, which may be reflective of the recent evolutionary history of A. cellulolyticus since its divergence from its closest phylogenetic neighbor Frankia, a mesophilic plant endosymbiont and soil dweller. However, ribosomal proteins and noncoding RNAs (rRNA and tRNAs) in A. cellulolyticus showed thermophilic traits suggesting the importance of adaptation of cellular translational machinery to environmental temperature. Elevated occurrence of IVYWREL amino acids in A. cellulolyticus orthologs compared to mesophiles and inverse preferences for G and A at the first and third codon positions also point to its ongoing thermoadaptation. Additional interesting features in the genome of this cellulolytic, hot-springs-dwelling prokaryote include a low occurrence of pseudogenes or mobile genetic elements, an unexpected complement of flagellar genes, and the presence of three laterally acquired genomic islands of likely ecophysiological value. PMID:19270083

  11. Determination of optimum insulation thickness in pipe for exergetic life cycle assessment

    International Nuclear Information System (INIS)

    Keçebaş, Ali

    2015-01-01

    Highlights: • It is aimed to determine optimum insulation thickness in pipe. • A new methodology is used as exergetic life cycle assessment for this purpose. • It is evaluated for various fuels, different pipe diameters and some combustion parameters. • This methodology is not suitable for determining optimum insulation thickness of a pipe. • There are benefits to our understanding of the need for insulation use in pipes. - Abstract: The energy saving and the environmental impacts’ reduction in the world building sector have gained great importance. Therefore, great efforts have been invested to create energy-saving green buildings. To do so, one of the many things to be done is the insulation of cylindrical pipes, canals and tanks. In the current study, the main focus is on the determination of the optimum insulation thickness of the pipes with varying diameters when different fuels are used. Therefore, through a new method combining exergy analysis and life cycle assessment, optimum insulation thickness of the pipes, total exergetic environmental impact, net saving and payback period were calculated. The effects of the insulation thickness on environmental and combustion parameters were analyzed in a detailed manner. The results revealed that optimum insulation thickness was affected by the temperature of the fuel when it enters into the combustion chamber, the temperature of the stack gas and the temperature of the combustion chamber. Under these optimum effects, the optimum insulation thickness of a 100 mm pipe was determined to be 55.7 cm, 57.2 cm and 59.3 cm for coal, natural gas and fuel–oil, respectively with the ratios of 76.32%, 81.84% and 84.04% net savings in the exergetic environmental impact. As the environmental impacts of the fuels and their products are bigger than those of the insulation material, the values of the optimum insulation thickness of the method used this study was found greater. Moreover, in the pipes with greater

  12. Carboxydobrachium pacificum gen. nov., sp. nov., a new anaerobic, thermophilic, CO-utilizing marine bacterium from Okinawa Trough.

    Science.gov (United States)

    Sokolova, T G; González, J M; Kostrikina, N A; Chernyh, N A; Tourova, T P; Kato, C; Bonch-Osmolovskaya, E A; Robb, F T

    2001-01-01

    A new anaerobic, thermophilic, CO-utilizing marine bacterium, strain JMT, was isolated from a submarine hot vent in Okinawa Trough. Cells of strain JMT were non-motile thin straight rods, sometimes branching, with a cell wall of the Gram-positive type, surrounded with an S-layer. Chains of three to five cells were often observed. The isolate grew chemolithotrophically on CO, producing equimolar quantities of H2 and CO2 (according to the equation CO+H2O-->CO2+H2) and organotrophically on peptone, yeast extract, starch, cellobiose, glucose, galactose, fructose and pyruvate, producing H2, acetate and CO2. Growth was observed from 50 to 80 degrees C with an optimum at 70 degrees C. The optimum pH was 6.8-7.1. The optimum concentration of sea salts in the medium was 20.5-25.5 g l(-1). The generation time under optimal conditions was 7.1 h. The DNA G+C content was 33 mol %. Growth of isolate JMT was not inhibited by penicillin, but ampicillin, streptomycin, kanamycin and neomycin completely inhibited growth. The results of 16S rDNA sequence analysis revealed that strain JMT belongs to the Thermoanaerobacter phylogenetic group within the Bacillus-Clostridium subphylum of Gram-positive bacteria but represents a separate branch of this group. On the basis of morphological and physiological features and phylogenetic data, this isolate should be assigned to a new genus, for which the name Carboxydobrachium is proposed. The type species is Carboxydobrachium pacificum; the type strain is JMT (= DSM 12653T).

  13. A Unique Autothermal Thermophilic Aerobic Digestion Process Showing a Dynamic Transition of Physicochemical and Bacterial Characteristics from the Mesophilic to the Thermophilic Phase.

    Science.gov (United States)

    Tashiro, Yukihiro; Kanda, Kosuke; Asakura, Yuya; Kii, Toshihiko; Cheng, Huijun; Poudel, Pramod; Okugawa, Yuki; Tashiro, Kosuke; Sakai, Kenji

    2018-03-15

    A unique autothermal thermophilic aerobic digestion (ATAD) process has been used to convert human excreta to liquid fertilizer in Japan. This study investigated the changes in physicochemical and bacterial community characteristics during the full-scale ATAD process operated for approximately 3 weeks in 2 different years. After initiating simultaneous aeration and mixing using an air-inducing circulator (aerator), the temperature autothermally increased rapidly in the first 1 to 2 days with exhaustive oxygen consumption, leading to a drastic decrease and gradual increase in oxidation-reduction potential in the first 2 days, reached >50°C in the middle 4 to 6 days, and remained steady in the final phase. Volatile fatty acids were rapidly consumed and diminished in the first 2 days, whereas the ammonia nitrogen concentration was relatively stable during the process, despite a gradual pH increase to 9.3. Principal-coordinate analysis of 16S rRNA gene amplicons using next-generation sequencing divided the bacterial community structures into distinct clusters corresponding to three phases, and they were similar in the final phase in both years despite different transitions in the middle phase. The predominant phyla (closest species, dominancy) in the initial, middle, and final phases were Proteobacteria ( Arcobacter trophiarum , 19 to 43%; Acinetobacter towneri , 6.3 to 30%), Bacteroidetes ( Moheibacter sediminis , 43 to 54%), and Firmicutes ( Thermaerobacter composti , 11 to 28%; Heliorestis baculata , 2.1 to 16%), respectively. Two predominant operational taxonomic units (OTUs) in the final phase showed very low similarities to the closest species, indicating that the process is unique compared with previously published ones. This unique process with three distinctive phases would be caused by the aerator with complete aeration. IMPORTANCE Although the autothermal thermophilic aerobic digestion (ATAD) process has several advantages, such as a high degradation

  14. Intercontinental dispersal of giant thermophilic ants across the Arctic during early Eocene hyperthermals.

    Science.gov (United States)

    Archibald, S Bruce; Johnson, Kirk R; Mathewes, Rolf W; Greenwood, David R

    2011-12-22

    Early Eocene land bridges allowed numerous plant and animal species to cross between Europe and North America via the Arctic. While many species suited to prevailing cool Arctic climates would have been able to cross throughout much of this period, others would have found dispersal opportunities only during limited intervals when their requirements for higher temperatures were met. Here, we present Titanomyrma lubei gen. et sp. nov. from Wyoming, USA, a new giant (greater than 5 cm long) formiciine ant from the early Eocene (approx. 49.5 Ma) Green River Formation. We show that the extinct ant subfamily Formiciinae is only known from localities with an estimated mean annual temperature of about 20°C or greater, consistent with the tropical ranges of almost all of the largest living ant species. This is, to our knowledge, the first known formiciine of gigantic size in the Western Hemisphere and the first reported cross-Arctic dispersal by a thermophilic insect group. This implies intercontinental migration during one or more brief high-temperature episodes (hyperthermals) sometime between the latest Palaeocene establishment of intercontinental land connections and the presence of giant formiciines in Europe and North America by the early middle Eocene.

  15. Thermophilic Adaptation in Prokaryotes Is Constrained by Metabolic Costs of Proteostasis

    Science.gov (United States)

    Venev, Sergey V; Zeldovich, Konstantin B

    2018-01-01

    Abstract Prokaryotes evolved to thrive in an extremely diverse set of habitats, and their proteomes bear signatures of environmental conditions. Although correlations between amino acid usage and environmental temperature are well-documented, understanding of the mechanisms of thermal adaptation remains incomplete. Here, we couple the energetic costs of protein folding and protein homeostasis to build a microscopic model explaining both the overall amino acid composition and its temperature trends. Low biosynthesis costs lead to low diversity of physical interactions between amino acid residues, which in turn makes proteins less stable and drives up chaperone activity to maintain appropriate levels of folded, functional proteins. Assuming that the cost of chaperone activity is proportional to the fraction of unfolded client proteins, we simulated thermal adaptation of model proteins subject to minimization of the total cost of amino acid synthesis and chaperone activity. For the first time, we predicted both the proteome-average amino acid abundances and their temperature trends simultaneously, and found strong correlations between model predictions and 402 genomes of bacteria and archaea. The energetic constraint on protein evolution is more apparent in highly expressed proteins, selected by codon adaptation index. We found that in bacteria, highly expressed proteins are similar in composition to thermophilic ones, whereas in archaea no correlation between predicted expression level and thermostability was observed. At the same time, thermal adaptations of highly expressed proteins in bacteria and archaea are nearly identical, suggesting that universal energetic constraints prevail over the phylogenetic differences between these domains of life. PMID:29106597

  16. 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.

  17. Intercontinental dispersal of giant thermophilic ants across the Arctic during early Eocene hyperthermals

    Science.gov (United States)

    Archibald, S. Bruce; Johnson, Kirk R.; Mathewes, Rolf W.; Greenwood, David R.

    2011-01-01

    Early Eocene land bridges allowed numerous plant and animal species to cross between Europe and North America via the Arctic. While many species suited to prevailing cool Arctic climates would have been able to cross throughout much of this period, others would have found dispersal opportunities only during limited intervals when their requirements for higher temperatures were met. Here, we present Titanomyrma lubei gen. et sp. nov. from Wyoming, USA, a new giant (greater than 5 cm long) formiciine ant from the early Eocene (approx. 49.5 Ma) Green River Formation. We show that the extinct ant subfamily Formiciinae is only known from localities with an estimated mean annual temperature of about 20°C or greater, consistent with the tropical ranges of almost all of the largest living ant species. This is, to our knowledge, the first known formiciine of gigantic size in the Western Hemisphere and the first reported cross-Arctic dispersal by a thermophilic insect group. This implies intercontinental migration during one or more brief high-temperature episodes (hyperthermals) sometime between the latest Palaeocene establishment of intercontinental land connections and the presence of giant formiciines in Europe and North America by the early middle Eocene. PMID:21543354

  18. Directed evolution of a β-mannanase from Rhizomucor miehei to improve catalytic activity in acidic and thermophilic conditions.

    Science.gov (United States)

    Li, Yan-Xiao; Yi, Ping; Yan, Qiao-Juan; Qin, Zhen; Liu, Xue-Qiang; Jiang, Zheng-Qiang

    2017-01-01

    β-Mannanase randomly cleaves the β-1,4-linked mannan backbone of hemicellulose, which plays the most important role in the enzymatic degradation of mannan. Although the industrial applications of β-mannanase have tremendously expanded in recent years, the wild-type β-mannanases are still defective for some industries. The glycoside hydrolase (GH) family 5 β-mannanase ( Rm Man5A) from Rhizomucor miehei shows many outstanding properties, such as high specific activity and hydrolysis property. However, owing to the low catalytic activity in acidic and thermophilic conditions, the application of Rm Man5A to the biorefinery of mannan biomasses is severely limited. To overcome the limitation, Rm Man5A was successfully engineered by directed evolution. Through two rounds of screening, a mutated β-mannanase (m Rm Man5A) with high catalytic activity in acidic and thermophilic conditions was obtained, and then characterized. The mutant displayed maximal activity at pH 4.5 and 65 °C, corresponding to acidic shift of 2.5 units in optimal pH and increase by 10 °C in optimal temperature. The catalytic efficiencies ( k cat / K m ) of m Rm Man5A towards many mannan substrates were enhanced more than threefold in acidic and thermophilic conditions. Meanwhile, the high specific activity and excellent hydrolysis property of Rm Man5A were inherited by the mutant m Rm Man5A after directed evolution. According to the result of sequence analysis, three amino acid residues were substituted in m Rm Man5A, namely Tyr233His, Lys264Met, and Asn343Ser. To identify the function of each substitution, four site-directed mutations (Tyr233His, Lys264Met, Asn343Ser, and Tyr233His/Lys264Met) were subsequently generated, and the substitutions at Tyr233 and Lys264 were found to be the main reason for the changes of m Rm Man5A. Through directed evolution of Rm Man5A, two key amino acid residues that controlled its catalytic efficiency under acidic and thermophilic conditions were identified

  19. Thermophilic and alkaliphilic Actinobacteria: Biology and potential applications

    Directory of Open Access Journals (Sweden)

    L eShivlata

    2015-09-01

    Full Text Available Microbes belonging to the phylum Actinobacteria are prolific sources of antibiotics, clinically useful bioactive compounds and industrially important enzymes. The focus of the current review is on the diversity and potential applications of thermophilic and alkaliphilic actinobacteria, which are highly diverse in their taxonomy and morphology with a variety of adaptations for surviving and thriving in hostile environments. The specific metabolic pathways in these actinobacteria are activated for elaborating pharmaceutically, agriculturally and biotechnologically relevant biomolecules/bioactive compounds, which find multifarious applications.

  20. 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.

  1. Thermophilic and alkaliphilic Actinobacteria: biology and potential applications

    Science.gov (United States)

    Shivlata, L.; Satyanarayana, Tulasi

    2015-01-01

    Microbes belonging to the phylum Actinobacteria are prolific sources of antibiotics, clinically useful bioactive compounds and industrially important enzymes. The focus of the current review is on the diversity and potential applications of thermophilic and alkaliphilic actinobacteria, which are highly diverse in their taxonomy and morphology with a variety of adaptations for surviving and thriving in hostile environments. The specific metabolic pathways in these actinobacteria are activated for elaborating pharmaceutically, agriculturally, and biotechnologically relevant biomolecules/bioactive compounds, which find multifarious applications. PMID:26441937

  2. An Optimum Solution for Electric Power Theft

    Directory of Open Access Journals (Sweden)

    Aamir Hussain Memon

    2013-07-01

    Full Text Available Electric power theft is a problem that continues to plague power sector across the whole country. Every year, the electricity companies face the line losses at an average 20-30% and according to power ministry estimation WAPDA companies lose more than Rs. 125 billion. Significantly, it is enough to destroy the entire power sector of country. According to sources 20% losses means the masses would have to pay extra 20% in terms of electricity tariffs. In other words, the innocent consumers pay the bills of those who steal electricity. For all that, no any permanent solution for this major issue has ever been proposed. We propose an applicable and optimum solution for this impassable problem. In our research, we propose an Electric power theft solution based on three stages; Transmission stage, Distribution stage, and User stage. Without synchronization among all, the complete solution can not be achieved. The proposed solution is simulated on NI (National Instruments Circuit Design Suite Multisim v.10.0. Our research work is an implicit and a workable approach towards the Electric power theft, as for conditions in Pakistan, which is bearing the brunt of power crises already

  3. Mesh networks: an optimum solution for AMR

    Energy Technology Data Exchange (ETDEWEB)

    Mimno, G.

    2003-12-01

    Characteristics of mesh networks and the advantage of using them in automatic meter reading equipment (AMR) are discussed. Mesh networks are defined as being similar to a fishing net made of knots and links. In mesh networks the knots represent meter sites and the links are the radio paths between the meter sites and the neighbourhood concentrator. In mesh networks any knot in the communications chain can link to any other and the optimum path is calculated by the network by hopping from meter to meter until the radio message reaches a concentrator. This mesh communications architecture is said to be vastly superior to many older types of radio-based meter reading technologies; its main advantage is that it not only significantly improves the economics of fixed network deployment, but also supports time-of-use metering, remote disconnect services and advanced features, such as real-time pricing, demand response, and other efficiency measures, providing a better return on investment and reliability.

  4. Optimum harvest maturity for Leymus chinensis seed

    Directory of Open Access Journals (Sweden)

    Jixiang Lin

    2016-06-01

    Full Text Available Timely harvest is critical to achieve maximum seed viability and vigour in agricultural production. However, little information exists concerning how to reap the best quality seeds of Leymus chinensis, which is the dominant and most promising grass species in the Songnen Grassland of Northern China. The objective of this study was to investigate and evaluate possible quality indices of the seeds at different days after peak anthesis. Seed quality at different development stages was assessed by the colours of the seed and lemmas, seed weight, moisture content, electrical conductivity of seed leachate and germination indices. Two consecutive years of experimental results showed that the maximum seed quality was recorded at 39 days after peak anthesis. At this date, the colours of the seed and lemmas reached heavy brown and yellow, respectively. The seed weight was highest and the moisture content and the electrical conductivity of seed leachate were lowest. In addition, the seed also reached its maximum germination percentage and energy at this stage, determined using a standard germination test (SGT and accelerated ageing test (AAT. Thus, Leymus chinensis can be harvested at 39 days after peak anthesis based on the changes in parameters. Colour identification can be used as an additional indicator to provide a more rapid and reliable measure of optimum seed maturity; approximately 10 days after the colour of the lemmas reached yellow and the colour of the seed reached heavy brown, the seed of this species was suitable for harvest.

  5. Designing from minimum to optimum functionality

    Science.gov (United States)

    Bannova, Olga; Bell, Larry

    2011-04-01

    This paper discusses a multifaceted strategy to link NASA Minimal Functionality Habitable Element (MFHE) requirements to a compatible growth plan; leading forward to evolutionary, deployable habitats including outpost development stages. The discussion begins by reviewing fundamental geometric features inherent in small scale, vertical and horizontal, pressurized module configuration options to characterize applicability to meet stringent MFHE constraints. A proposed scenario to incorporate a vertical core MFHE concept into an expanded architecture to provide continuity of structural form and a logical path from "minimum" to "optimum" design of a habitable module. The paper describes how habitation and logistics accommodations could be pre-integrated into a common Hab/Log Module that serves both habitation and logistics functions. This is offered as a means to reduce unnecessary redundant development costs and to avoid EVA-intensive on-site adaptation and retrofitting requirements for augmented crew capacity. An evolutionary version of the hard shell Hab/Log design would have an expandable middle section to afford larger living and working accommodations. In conclusion, the paper illustrates that a number of cargo missions referenced for NASA's 4.0.0 Lunar Campaign Scenario could be eliminated altogether to expedite progress and reduce budgets. The plan concludes with a vertical growth geometry that provides versatile and efficient site development opportunities using a combination of hard Hab/Log modules and a hybrid expandable "CLAM" (Crew Lunar Accommodations Module) element.

  6. Achieving optimum diffraction based overlay performance

    Science.gov (United States)

    Leray, Philippe; Laidler, David; Cheng, Shaunee; Coogans, Martyn; Fuchs, Andreas; Ponomarenko, Mariya; van der Schaar, Maurits; Vanoppen, Peter

    2010-03-01

    Diffraction Based Overlay (DBO) metrology has been shown to have significantly reduced Total Measurement Uncertainty (TMU) compared to Image Based Overlay (IBO), primarily due to having no measurable Tool Induced Shift (TIS). However, the advantages of having no measurable TIS can be outweighed by increased susceptibility to WIS (Wafer Induced Shift) caused by target damage, process non-uniformities and variations. The path to optimum DBO performance lies in having well characterized metrology targets, which are insensitive to process non-uniformities and variations, in combination with optimized recipes which take advantage of advanced DBO designs. In this work we examine the impact of different degrees of process non-uniformity and target damage on DBO measurement gratings and study their impact on overlay measurement accuracy and precision. Multiple wavelength and dual polarization scatterometry are used to characterize the DBO design performance over the range of process variation. In conclusion, we describe the robustness of DBO metrology to target damage and show how to exploit the measurement capability of a multiple wavelength, dual polarization scatterometry tool to ensure the required measurement accuracy for current and future technology nodes.

  7. Optimum copper to superconductor ratio in cables for superconducting magnets at 1.9 K

    International Nuclear Information System (INIS)

    Wolf, R.

    1994-01-01

    In this paper the optimum copper to superconducting ratio is calculated to prevent quenching for superconducting cables used in accelerator magnets like the LHC dipoles, operating in superfluid helium at 1.9K. The duration of the perturbations leading to a quench are estimated from flux measurements made with pickup coils in the LHC dipole models. The optimum copper to superconducting ratio is then found by studying the minimum quench energy and the influence of the length and the duration or the perturbation and heat transfer to the surroundings. A comparison is made of the behavior at temperatures of 1.9 and 4.3 K

  8. Optimum solar collector fluid flow rates

    DEFF Research Database (Denmark)

    Furbo, Simon; Shah, Louise Jivan

    1996-01-01

    Experiments showed that by means of a standard electronically controlled pump, type UPE 2000 from Grundfos it is possible to control the flow rate in a solar collector loop in such a way that the flow rate is strongly influenced by the temperature of the solar collector fluid passing the pump....... The flow rate is increasing for increasing temperature.The flow rate at the high temperature level is typically 70 % greater than the flow rate at the low temperature level.Further, the energy consumption for the electronically controlled pump in a solar heating system will be somewhat smaller than...... the energy consumption of a normal ciculation pump in the solar heating system.Calculations showed that the highest thermal performances for small SDHW systems based on mantle tanks with constant volume flow rates in the solar collector loops are achieved if the flow rate is situated in the interval from 0...

  9. Aeribacillus composti sp. nov., a thermophilic bacillus isolated from olive mill pomace compost.

    Science.gov (United States)

    Finore, Ilaria; Gioiello, Alessia; Leone, Luigi; Orlando, Pierangelo; Romano, Ida; Nicolaus, Barbara; Poli, Annarita

    2017-11-01

    A Gram-stain-positive, aerobic, endospore-forming, thermophilic bacterium, strain N.8 T , was isolated from the curing step of an olive mill pomace compost sample, collected at the Composting Experimental Centre (CESCO, Salerno, Italy). Strain N.8 T , based on 16S rRNA gene sequence similarities, was most closely related to Aeribacillus pallidus strain H12 T (=DSM 3670 T ) (99.8 % similarity value) with a 25 % DNA-DNA relatedness value. Cells were rod-shaped, non-motile and grew optimally at 60 °C and pH 9.0, forming cream colonies. Strain N.8 was able to grow on medium containing up to 9.0 % (w/v) NaCl with an optimum at 6.0 % (w/v) NaCl. The cellular membrane contained MK-7, and C16 : 0 (48.4 %), iso-C17 : 0 (19.4 %) and anteiso-C17 : 0 (14.6 %) were the major cellular fatty acids. The DNA G+C content was 40.5 mol%. Based on phenotypic characteristics, 16S rRNA gene sequences, DNA-DNA hybridization values and chemotaxonomic characteristics, strain N.8 T represents a novel species of the genus Aeribacillus, for which the name Aeribacillus composti sp. nov. is proposed. The type strain is N.8 T (=KCTC 33824 T =JCM 31580 T ).

  10. Effects of Calcium Ions on the Thermostability and Spectroscopic Properties of the LH1-RC Complex from a New Thermophilic Purple Bacterium Allochromatium tepidum.

    Science.gov (United States)

    Kimura, Yukihiro; Lyu, Shuwen; Okoshi, Akira; Okazaki, Koudai; Nakamura, Natsuki; Ohashi, Akira; Ohno, Takashi; Kobayashi, Manami; Imanishi, Michie; Takaichi, Shinichi; Madigan, Michael T; Wang-Otomo, Zheng-Yu

    2017-05-18

    The light harvesting-reaction center (LH1-RC) complex from a new thermophilic purple sulfur bacterium Allochromatium (Alc.) tepidum was isolated and characterized by spectroscopic and thermodynamic analyses. The purified Alc. tepidum LH1-RC complex showed a high thermostability comparable to that of another thermophilic purple sulfur bacterium Thermochromatium tepidum, and spectroscopic characteristics similar to those of a mesophilic bacterium Alc. vinosum. Approximately 4-5 Ca 2+ per LH1-RC were detected by inductively coupled plasma atomic emission spectroscopy and isothermal titration calorimetry. Upon removal of Ca 2+ , the denaturing temperature of the Alc. tepidum LH1-RC complex dropped accompanied by a blue-shift of the LH1 Q y absorption band. The effect of Ca 2+ was also observed in the resonance Raman shift of the C3-acetyl νC═O band of bacteriochlorophyll-a, indicating changes in the hydrogen-bonding interactions between the pigment and LH1 polypeptides. Thermodynamic parameters for the Ca 2+ -binding to the Alc. tepidum LH1-RC complex indicated that this reaction is predominantly driven by the largely favorable electrostatic interactions that counteract the unfavorable negative entropy change. Our data support a hypothesis that Alc. tepidum may be a transitional organism between mesophilic and thermophilic purple bacteria and that Ca 2+ is one of the major keys to the thermostability of LH1-RC complexes in purple bacteria.

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

    Science.gov (United States)

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

    2010-02-01

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

  12. Relationship between microbial community dynamics and process performance during thermophilic sludge bioleaching.

    Science.gov (United States)

    Chen, Shen-Yi; Chou, Li-Chieh

    2016-08-01

    Heavy metals can be removed from the sludge using bioleaching technologies at thermophilic condition, thereby providing an option for biotreatment of wasted sludge generated from wastewater treatment. The purposes of this study were to establish a molecular biology technique, real-time PCR, for the detection and enumeration of the sulfur-oxidizing bacteria during the thermophilic sludge bioleaching. The 16S rRNA gene for real-time PCR quantification targeted the bioleaching bacteria: Sulfobacillus thermosulfidooxidans, Sulfobacillus acidophilus, and Acidithiobacillus caldus. The specificity and stringency for thermophilic sulfur-oxidizing bacteria were tested before the experiments of monitoring the bacterial community, bacterial number during the thermophilic sludge bioleaching and the future application on testing various environmental samples. The results showed that S. acidophilus was identified as the dominant sulfur-oxidizing bacteria, while A. caldus and S. thermosulfidooxidans occurred in relatively low numbers. The total number of the sulfur-oxidizing bacteria increased during the thermophilic bioleaching process. Meanwhile, the decrease of pH, production of sulfate, degradation of SS/VSS, and solubilization of heavy metal were found to correlate well with the population of thermophilic sulfur-oxidizing bacteria during the bioleaching process. The real-time PCR used in this study is a suitable method to monitor numbers of thermophilic sulfur-oxidizing bacteria during the bioleaching process.

  13. Optimum Image Formation for Spaceborne Microwave Radiometer Products.

    Science.gov (United States)

    Long, David G; Brodzik, Mary J

    2016-05-01

    This paper considers some of the issues of radiometer brightness image formation and reconstruction for use in the NASA-sponsored Calibrated Passive Microwave Daily Equal-Area Scalable Earth Grid 2.0 Brightness Temperature Earth System Data Record project, which generates a multisensor multidecadal time series of high-resolution radiometer products designed to support climate studies. Two primary reconstruction algorithms are considered: the Backus-Gilbert approach and the radiometer form of the scatterometer image reconstruction (SIR) algorithm. These are compared with the conventional drop-in-the-bucket (DIB) gridded image formation approach. Tradeoff study results for the various algorithm options are presented to select optimum values for the grid resolution, the number of SIR iterations, and the BG gamma parameter. We find that although both approaches are effective in improving the spatial resolution of the surface brightness temperature estimates compared to DIB, SIR requires significantly less computation. The sensitivity of the reconstruction to the accuracy of the measurement spatial response function (MRF) is explored. The partial reconstruction of the methods can tolerate errors in the description of the sensor measurement response function, which simplifies the processing of historic sensor data for which the MRF is not known as well as modern sensors. Simulation tradeoff results are confirmed using actual data.

  14. Structural Insights into the Thermophilic Adaption Mechanism of Endo-1,4-β-Xylanase from Caldicellulosiruptor owensensis.

    Science.gov (United States)

    Liu, Xin; Liu, Tengfei; Zhang, Yuebin; Xin, Fengjiao; Mi, Shuofu; Wen, Boting; Gu, Tianyi; Shi, Xinyuan; Wang, Fengzhong; Sun, Lichao

    2018-01-10

    Xylanases (EC 3.2.1.8) are a kind of enzymes degrading xylan to xylooligosaccharides (XOS) and have been widely used in a variety of industrial applications. Among them, xylanases from thermophilic microorganisms have distinct advantages in industries that require high temperature conditions. The CoXynA gene, encoding a glycoside hydrolase (GH) family 10 xylanase, was identified from thermophilic Caldicellulosiruptor owensensis and was overexpressed in Escherichia coli. Recombinant CoXynA showed optimal activity at 90 °C with a half-life of about 1 h at 80 °C and exhibited highest activity at pH 7.0. The activity of CoXynA activity was affected by a variety of cations. CoXynA showed distinct substrate specificities for beechwood xylan and birchwood xylan. The crystal structure of CoXynA was solved and a molecular dynamics simulation of CoXynA was performed. The relatively high thermostability of CoXynA was proposed to be due to the increased overall protein rigidity resulting from the reduced length and fluctuation of Loop 7.

  15. Deferribacter thermophilus gen. nov., sp. nov., a novel thermophilic manganese- and iron-reducing bacterium isolated from a petroleum reservoir.

    Science.gov (United States)

    Greene, A C; Patel, B K; Sheehy, A J

    1997-04-01

    A thermophilic anaerobic bacterium, designated strain BMAT (T = type strain), was isolated from the production water of Beatrice oil field in the North Sea (United Kingdom). The cells were straight to bent rods (1 to 5 by 0.3 to 0.5 microns) which stained gram negative. Strain BMAT obtained energy from the reduction of manganese (IV), iron(III), and nitrate in the presence of yeast extract, peptone, Casamino Acids, tryptone, hydrogen, malate, acetate, citrate, pyruvate, lactate, succinate, and valerate. The isolate grew optimally at 60 degrees C (temperature range for growth, 50 to 65 degrees C) and in the presence of 2% (wt/vol) NaCl (NaCl range for growth, 0 to 5% [wt/vol]). The DNA base composition was 34 mol% G + C. Phylogenetic analyses of the 16S rRNA gene indicated that strain BMAT is a member of the domain Bacteria. The closest known bacterium is the moderate thermophile Flexistipes sinusarabici (similarity value, 88%). Strain BMAT possesses phenotypic and phylogenetic traits that do not allow its classification as a member of any previously described genus; therefore, we propose that this isolate should be described as a member of a novel species of a new genus, Deferribacter thermophilus gen. nov., sp. nov.

  16. Implementation of optimum solar electricity generating system

    International Nuclear Information System (INIS)

    Singh, Balbir Singh Mahinder; Karim, Samsul Ariffin A.; Sivapalan, Subarna; Najib, Nurul Syafiqah Mohd; Menon, Pradeep

    2014-01-01

    Under the 10 th Malaysian Plan, the government is expecting the renewable energy to contribute approximately 5.5% to the total electricity generation by the year 2015, which amounts to 98MW. One of the initiatives to ensure that the target is achievable was to establish the Sustainable Energy Development Authority of Malaysia. SEDA is given the authority to administer and manage the implementation of the feed-in tariff (FiT) mechanism which is mandated under the Renewable Energy Act 2011. The move to establish SEDA is commendable and the FiT seems to be attractive but there is a need to create awareness on the implementation of the solar electricity generating system (SEGS). In Malaysia, harnessing technologies related to solar energy resources have great potential for implementation. However, the main issue that plagues the implementation of SEGS is the intermittent nature of this source of energy. The availability of sunlight is during the day time, and there is a need for electrical energy storage system, so that there is electricity available during the night time as well. The meteorological condition such as clouds, haze and pollution affects the SEGS as well. The PV based SEGS is seems to be promising electricity generating system that can contribute towards achieving the 5.5% target and will be able to minimize the negative effects of utilizing fossil fuels for electricity generation on the environment. Malaysia is committed to Kyoto Protocol, which emphasizes on fighting global warming by achieving stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. In this paper, the technical aspects of the implementation of optimum SEGS is discussed, especially pertaining to the positioning of the PV panels

  17. Implementation of optimum solar electricity generating system

    Science.gov (United States)

    Singh, Balbir Singh Mahinder; Sivapalan, Subarna; Najib, Nurul Syafiqah Mohd; Menon, Pradeep; Karim, Samsul Ariffin A.

    2014-10-01

    Under the 10th Malaysian Plan, the government is expecting the renewable energy to contribute approximately 5.5% to the total electricity generation by the year 2015, which amounts to 98MW. One of the initiatives to ensure that the target is achievable was to establish the Sustainable Energy Development Authority of Malaysia. SEDA is given the authority to administer and manage the implementation of the feed-in tariff (FiT) mechanism which is mandated under the Renewable Energy Act 2011. The move to establish SEDA is commendable and the FiT seems to be attractive but there is a need to create awareness on the implementation of the solar electricity generating system (SEGS). In Malaysia, harnessing technologies related to solar energy resources have great potential for implementation. However, the main issue that plagues the implementation of SEGS is the intermittent nature of this source of energy. The availability of sunlight is during the day time, and there is a need for electrical energy storage system, so that there is electricity available during the night time as well. The meteorological condition such as clouds, haze and pollution affects the SEGS as well. The PV based SEGS is seems to be promising electricity generating system that can contribute towards achieving the 5.5% target and will be able to minimize the negative effects of utilizing fossil fuels for electricity generation on the environment. Malaysia is committed to Kyoto Protocol, which emphasizes on fighting global warming by achieving stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. In this paper, the technical aspects of the implementation of optimum SEGS is discussed, especially pertaining to the positioning of the PV panels.

  18. Implementation of optimum solar electricity generating system

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Balbir Singh Mahinder, E-mail: balbir@petronas.com.my; Karim, Samsul Ariffin A., E-mail: samsul-ariffin@petronas.com.my [Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS, 31750 Bandar Seri Iskandar, Perak (Malaysia); Sivapalan, Subarna, E-mail: subarna-sivapalan@petronas.com.my [Department of Management and Humanities, Universiti Teknologi PETRONAS, 31750 Bandar Seri Iskandar, Perak (Malaysia); Najib, Nurul Syafiqah Mohd; Menon, Pradeep [Department of Electrical and Electronics Engineering, Universiti Teknologi PETRONAS, 31750 Bandar Seri Iskandar, Perak (Malaysia)

    2014-10-24

    Under the 10{sup th} Malaysian Plan, the government is expecting the renewable energy to contribute approximately 5.5% to the total electricity generation by the year 2015, which amounts to 98MW. One of the initiatives to ensure that the target is achievable was to establish the Sustainable Energy Development Authority of Malaysia. SEDA is given the authority to administer and manage the implementation of the feed-in tariff (FiT) mechanism which is mandated under the Renewable Energy Act 2011. The move to establish SEDA is commendable and the FiT seems to be attractive but there is a need to create awareness on the implementation of the solar electricity generating system (SEGS). In Malaysia, harnessing technologies related to solar energy resources have great potential for implementation. However, the main issue that plagues the implementation of SEGS is the intermittent nature of this source of energy. The availability of sunlight is during the day time, and there is a need for electrical energy storage system, so that there is electricity available during the night time as well. The meteorological condition such as clouds, haze and pollution affects the SEGS as well. The PV based SEGS is seems to be promising electricity generating system that can contribute towards achieving the 5.5% target and will be able to minimize the negative effects of utilizing fossil fuels for electricity generation on the environment. Malaysia is committed to Kyoto Protocol, which emphasizes on fighting global warming by achieving stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. In this paper, the technical aspects of the implementation of optimum SEGS is discussed, especially pertaining to the positioning of the PV panels.

  19. A portable anaerobic microbioreactor reveals optimum growth conditions for the methanogen Methanosaeta concilii.

    Science.gov (United States)

    Steinhaus, Benjamin; Garcia, Marcelo L; Shen, Amy Q; Angenent, Largus T

    2007-03-01

    Conventional studies of the optimum growth conditions for methanogens (methane-producing, obligate anaerobic archaea) are typically conducted with serum bottles or bioreactors. The use of microfluidics to culture methanogens allows direct microscopic observations of the time-integrated response of growth. Here, we developed a microbioreactor (microBR) with approximately 1-microl microchannels to study some optimum growth conditions for the methanogen Methanosaeta concilii. The microBR is contained in an anaerobic chamber specifically designed to place it directly onto an inverted light microscope stage while maintaining a N2-CO2 environment. The methanogen was cultured for months inside microchannels of different widths. Channel width was manipulated to create various fluid velocities, allowing the direct study of the behavior and responses of M. concilii to various shear stresses and revealing an optimum shear level of approximately 20 to 35 microPa. Gradients in a single microchannel were then used to find an optimum pH level of 7.6 and an optimum total NH4-N concentration of less than 1,100 mg/liter (<47 mg/liter as free NH3-N) for M. concilii under conditions of the previously determined ideal shear stress and pH and at a temperature of 35 degrees C.

  20. ANAEROBIC BIODEGRADATION OF A BIODEGRADABLE MATERIAL UNDER ANAEROBIC - THERMOPHILIC DIGESTION

    Directory of Open Access Journals (Sweden)

    RICARDO CAMACHO-MUÑOZ

    2014-12-01

    Full Text Available This paper dertermined the anaerobic biodegradation of a polymer obtained by extrusion process of native cassava starch, polylactic acid and polycaprolactone. Initially a thermophilic - methanogenic inoculum was prepared from urban solid waste. The gas final methane concentration and medium’s pH reached values of 59,6% and 7,89 respectively. The assay assembly was carried out according ASTM D5511 standard. The biodegradation percent of used materials after 15 day of digestion were: 77,49%, 61,27%, 0,31% for cellulose, sample and polyethylene respectively. Due cellulose showed biodegradation levels higher than 70% it’s deduced that the inoculum conditions were appropriate. A biodegradation level of 61,27%, 59,35% of methane concentration in sample’s evolved gas and a medium’s finale pH of 7,71 in sample’s vessels, reveal the extruded polymer´s capacity to be anaerobically degraded under thermophilic- high solid concentration conditions.

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

    Science.gov (United States)

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

    2016-11-17

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

  2. Efficient plant biomass degradation by thermophilic fungus Myceliophthora heterothallica.

    Science.gov (United States)

    van den Brink, Joost; van Muiswinkel, Gonny C J; Theelen, Bart; Hinz, Sandra W A; de Vries, Ronald P

    2013-02-01

    Rapid and efficient enzymatic degradation of plant biomass into fermentable sugars is a major challenge for the sustainable production of biochemicals and biofuels. Enzymes that are more thermostable (up to 70°C) use shorter reaction times for the complete saccharification of plant polysaccharides compared to hydrolytic enzymes of mesophilic fungi such as Trichoderma and Aspergillus species. The genus Myceliophthora contains four thermophilic fungi producing industrially relevant thermostable enzymes. Within this genus, isolates belonging to M. heterothallica were recently separated from the well-described species M. thermophila. We evaluate here the potential of M. heterothallica isolates to produce efficient enzyme mixtures for biomass degradation. Compared to the other thermophilic Myceliophthora species, isolates belonging to M. heterothallica and M. thermophila grew faster on pretreated spruce, wheat straw, and giant reed. According to their protein profiles and in vitro assays after growth on wheat straw, (hemi-)cellulolytic activities differed strongly between M. thermophila and M. heterothallica isolates. Compared to M. thermophila, M. heterothallica isolates were better in releasing sugars from mildly pretreated wheat straw (with 5% HCl) with a high content of xylan. The high levels of residual xylobiose revealed that enzyme mixtures of Myceliophthora species lack sufficient β-xylosidase activity. Sexual crossing of two M. heterothallica showed that progenies had a large genetic and physiological diversity. In the future, this will allow further improvement of the plant biomass-degrading enzyme mixtures of M. heterothallica.

  3. Electricity production and microbial characterization of thermophilic microbial fuel cells.

    Science.gov (United States)

    Dai, Kun; Wen, Jun-Li; Zhang, Fang; Ma, Xi-Wen; Cui, Xiang-Yu; Zhang, Qi; Zhao, Ting-Jia; Zeng, Raymond J

    2017-11-01

    Thermophilic microbial fuel cell (TMFC) offers many benefits, but the investigations on the diversity of exoelectrogenic bacteria are scarce. In this study, a two-chamber TMFC was constructed using ethanol as an electron donor, and the microbial dynamics were analyzed by high-throughput sequencing and 16S rRNA clone-library sequencing. The open-circuit potential of TMFC was approximately 650mV, while the maximum voltage was around 550mV. The maximum power density was 437mW/m 2 , and the columbic efficiency in this work was 20.5±6.0%. The Firmicutes bacteria, related to the uncultured bacterium clone A55_D21_H_B_C01 with a similarity of 99%, accounted for 90.9% of all bacteria in the TMFC biofilm. This unknown bacterium has the potential to become a new thermophilic exoelectrogenic bacterium that is yet to be cultured. The development of TMFC-involved biotechnologies will be beneficial for the production of valuable chemicals and generation of energy in the future. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Global transport of thermophilic bacteria in atmospheric dust.

    Science.gov (United States)

    Perfumo, Amedea; Marchant, Roger

    2010-04-01

    Aerosols from dust storms generated in the Sahara-Sahel desert area of Africa are transported north over Europe and periodically result in dry dust precipitation in the Mediterranean region. Samples of dust collected in Turkey and Greece following two distinct desert storm events contained viable thermophilic organisms of the genus Geobacillus, namely G. thermoglucosidasius and G. thermodenitrificans, and the recently reclassified Aeribacillus pallidus (formerly Geobacillus pallidus). We present here evidence that African dust storms create an atmospheric bridge between distant geographical regions and that they are also probably the source of thermophilic geobacilli later deposited over northern Europe by rainfall or dust plumes themselves. The same organisms (99% similarity in the 16S rDNA sequence) were found in dust collected in the Mediterranean region and inhabiting cool soils in Northern Ireland. This study also contributes new insights to the taxonomic identification of Geobacillus sp. Attempts to identify these organisms using 16S rRNA gene sequences have revealed that they contain multiple and diverse copies of the ribosomal RNA operon (up to 10 copies with nine different sequences), which dictates care in interpreting data about the systematics of this genus. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

  5. 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)

  6. Optimum operating regimes of common paramagnetic refrigerants

    CERN Document Server

    Wikus, P; Figueroa-Feliciano, E

    2011-01-01

    Adiabatic Demagnetization Refrigerators (ADRs) are commonly used in cryogenic laboratories to achieve subkelvin temperatures. ADRs are also the technology of choice for several space borne instruments which make use of cryogenic microcalorimeters or bolometers {[}1-4]. For these applications, refrigerants with high ratios of cooling capacity to volume, or cooling capacity to mass are usually required. In this manuscript, two charts for the simple selection of the most suitable of several common refrigerants (CAA, CMN, CPA, DGG, FAA, GGG, GLF and MAS) are presented. These graphs are valid for single stage cycles. The selection of the refrigerants is uniquely dependent on the starting conditions of the refrigeration cycle (temperature and magnetic field density) and the desired final temperature. Only thermodynamic properties of the refrigerants have been taken into account, and other important factors such as availability and manufacturability have not been considered. (C) 2011 Elsevier Ltd. All rights reserve...

  7. Enzyme activity screening of thermophilic bacteria isolated from Dusun Tua Hot Spring, Malaysia

    Science.gov (United States)

    Msarah, Marwan; Ibrahim, Izyanti; Aqma, Wan Syaidatul

    2018-04-01

    Thermophilic bacteria have biotechnological importance due to the availability of unique enzymes which are stable in extreme circumstances. The aim of this study includes to isolate thermophilic bacteria from hot spring and screen for important enzyme activities. Water samples from the Dusun Tua Hot Spring were collected and the physiochemical characterisation of water was measured. Eight thermophilic bacteria were isolated and determined to have at least three strong enzyme activity including protease, lipase, amylase, cellulase, pectinase and xylanase. The results showed that HuluC2 displayed all the enzyme activities and can be further studied.

  8. Optimum gain and phase for stochastic cooling systems

    International Nuclear Information System (INIS)

    Meer, S. van der.

    1984-01-01

    A detailed analysis of optimum gain and phase adjustment in stochastic cooling systems reveals that the result is strongly influenced by the beam feedback effect and that for optimum performance the system phase should change appreciably across each Schottky band. It is shown that the performance is not greatly diminished if a constant phase is adopted instead. On the other hand, the effect of mixing between pick-up and kicker (which produces a phase change similar to the optimum one) is shown to be less perturbing than is usually assumed, provided that the absolute value of the gain is not too far from the optimum value. (orig.)

  9. Fermentation Process of Cocoa Based on Optimum Condition of Pulp PectinDepolymerization by Endogenous Pectolityc Enzymes

    OpenAIRE

    Ganda-Putra, G.P; Wrasiati, L.P; Wartini, N.M

    2010-01-01

    Pulp degradation during cocoa fermentation can be carried out by depolymerization process of pulp pectin using endogenous pectolytic enzymes at optimum condition. The objectives of this research were to study the effect of fermentation process based on optimum condition in terms of temperature and pH of pulp pectin depolymerization using endogenous pectolytic enzymes polygalakturonase (PG) and pectin metyl esterase (PME) and fermentation period in cocoa processing on quality characteristics o...

  10. 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

    Thermophilic (55 deg) pre-hydrolysis has been shown to improve methane yield, organics reduction and/or treatment capacity when applied to anaerobic digestion (Persson m. fl. 2010). The method has also proven to kill off pathogens, making it an interesting hygienisation alternative to pasteurisation. The Swedish Environmental Protection Agency has opened up for the possibility to validate new methods for hygienisation, if the pathogen reduction can be proven to be efficient enough. Thermophilic pre-hydrolysis has several possible advantages to pasteurization; e. g. district heating of lower temperature can be used, the stability of the process may increase, as well as the efficiency and extent of the digestion process. The objective of this study is to evaluate the effect of thermophilic pre-hydrolysis on anaerobic digestion (AD) of sewage sludge with respect to: 1. Biogas/methane production and solids reduction. 2. Correlations between substrate properties, process conditions and effect on the AD process. 3. Pathogen reduction efficiency. 4. Operational consequences. Laboratory trials in continuous and batch mode were conducted on sewage sludge from four Swedish wastewater treatment plants. In the trials thermophilic pre-hydrolysis with consecutive mesophilic AD was compared to conventional one-step mesophilic AD, as well as pre-pasteurisation with consecutive AD. For all the tested sludge samples the reduction of TS and VS increased as a result of thermophilic pre-hydrolysis prior to mesophilic AD. The results with respect to methane yield were not as straightforward. Increased production of biogas was achieved in pilot scale, but the methane production did not improve. In the laboratory trials the effect on methane production varied from -8 % till +18 % for the sludge samples tested. The most positive results were achieved in the test that had the highest organic load and that was fed with a sludge that was low in fat and high in carbohydrates, compared to the

  11. Thermophilic archaeal community succession and function change associated with the leaching rate in bioleaching of chalcopyrite.

    Science.gov (United States)

    Zhu, Wei; Xia, Jin-lan; Yang, Yi; Nie, Zhen-yuan; Peng, An-an; Liu, Hong-chang; Qiu, Guan-zhou

    2013-04-01

    The community succession and function change of thermophilic archaea Acidianus brierleyi, Metallosphaera sedula, Acidianus manzaensis and Sulfolobus metallicus were studied by denaturing gradient gel electrophoresis (DGGE) analysis of amplifying 16S rRNA genes fragments and real-time qPCR analysis of amplifying sulfur-oxidizing soxB gene associated with chalcopyrite bioleaching rate at different temperatures and initial pH values. The analysis results of the community succession indicated that temperature and initial pH value had a significant effect on the consortium, and S. metallicus was most sensitive to the environmental change, A. brierleyi showed the best adaptability and sulfur oxidation ability and predominated in various leaching systems. Meanwhile, the leaching rate of chalcopyrite closely related to the consortium function embodied by soxB gene, which could prove a desirable way for revealing microbial sulfur oxidation difference and tracking the function change of the consortium, and for optimizing the leaching parameters and improving the recovery of valuable metals. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1984-05-01

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

  13. Characterization of a Y-Family DNA Polymerase eta from the Eukaryotic Thermophile Alvinella pompejana

    Science.gov (United States)

    Kashiwagi, Sayo; Kuraoka, Isao; Fujiwara, Yoshie; Hitomi, Kenichi; Cheng, Quen J.; Fuss, Jill O.; Shin, David S.; Masutani, Chikahide; Tainer, John A.; Hanaoka, Fumio; Iwai, Shigenori

    2010-01-01

    Human DNA polymerase η (HsPolη) plays an important role in translesion synthesis (TLS), which allows for replication past DNA damage such as UV-induced cis-syn cyclobutane pyrimidine dimers (CPDs). Here, we characterized ApPolη from the thermophilic worm Alvinella pompejana, which inhabits deep-sea hydrothermal vent chimneys. ApPolη shares sequence homology with HsPolη and contains domains for binding ubiquitin and proliferating cell nuclear antigen. Sun-induced UV does not penetrate Alvinella's environment; however, this novel DNA polymerase catalyzed efficient and accurate TLS past CPD, as well as 7,8-dihydro-8-oxoguanine and isomers of thymine glycol induced by reactive oxygen species. In addition, we found that ApPolη is more thermostable than HsPolη, as expected from its habitat temperature. Moreover, the activity of this enzyme was retained in the presence of a higher concentration of organic solvents. Therefore, ApPolη provides a robust, human-like Polη that is more active after exposure to high temperatures and organic solvents. PMID:20936172

  14. Cloning, Expression, and Characterization of a Novel Thermophilic Monofunctional Catalase from Geobacillus sp. CHB1

    Science.gov (United States)

    2016-01-01

    Catalases are widely used in many scientific areas. A catalase gene (Kat) from Geobacillus sp. CHB1 encoding a monofunctional catalase was cloned and recombinant expressed in Escherichia coli (E. coli), which was the first time to clone and express this type of catalase of genus Geobacillus strains as far as we know. This Kat gene was 1,467 bp in length and encoded a catalase with 488 amino acid residuals, which is only 81% similar to the previously studied Bacillus sp. catalase in terms of amino acid sequence. Recombinant catalase was highly soluble in E. coli and made up 30% of the total E. coli protein. Fermentation broth of the recombinant E. coli showed a high catalase activity level up to 35,831 U/mL which was only lower than recombinant Bacillus sp. WSHDZ-01 among the reported catalase production strains. The purified recombinant catalase had a specific activity of 40,526 U/mg and K m of 51.1 mM. The optimal reaction temperature of this recombinant enzyme was 60°C to 70°C, and it exhibited high activity over a wide range of reaction temperatures, ranging from 10°C to 90°C. The enzyme retained 94.7% of its residual activity after incubation at 60°C for 1 hour. High yield and excellent thermophilic properties are valuable features for this catalase in industrial applications. PMID:27579320

  15. Cloning, Expression, and Characterization of a Novel Thermophilic Monofunctional Catalase from Geobacillus sp. CHB1.

    Science.gov (United States)

    Jia, Xianbo; Chen, Jichen; Lin, Chenqiang; Lin, Xinjian

    2016-01-01

    Catalases are widely used in many scientific areas. A catalase gene (Kat) from Geobacillus sp. CHB1 encoding a monofunctional catalase was cloned and recombinant expressed in Escherichia coli (E. coli), which was the first time to clone and express this type of catalase of genus Geobacillus strains as far as we know. This Kat gene was 1,467 bp in length and encoded a catalase with 488 amino acid residuals, which is only 81% similar to the previously studied Bacillus sp. catalase in terms of amino acid sequence. Recombinant catalase was highly soluble in E. coli and made up 30% of the total E. coli protein. Fermentation broth of the recombinant E. coli showed a high catalase activity level up to 35,831 U/mL which was only lower than recombinant Bacillus sp. WSHDZ-01 among the reported catalase production strains. The purified recombinant catalase had a specific activity of 40,526 U/mg and K m of 51.1 mM. The optimal reaction temperature of this recombinant enzyme was 60°C to 70°C, and it exhibited high activity over a wide range of reaction temperatures, ranging from 10°C to 90°C. The enzyme retained 94.7% of its residual activity after incubation at 60°C for 1 hour. High yield and excellent thermophilic properties are valuable features for this catalase in industrial applications.

  16. Production and localization of cellulases and. beta. -glucosidase from the thermophilic fungus Thielavia terrestris

    Energy Technology Data Exchange (ETDEWEB)

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

    1986-01-01

    The enzyme production and localization of Thielavia terrestris strains C464 and NRRL 8126 were compared to determine their optimum temperature and pH for cellulase activity. High levels of intracellular ..beta..-glucosidase activity were detected in the former strain. The intracellular ..beta..-glucosidase of both strains were more thermostable than the extra-cellular enzyme; the half life of T. terrestris (C464) endoglucanase activity at 60 degrees C was greater than 96 hours. 12 references.

  17. Quantitative Metaproteomics Highlight the Metabolic Contributions of Uncultured Phylotypes in a Thermophilic Anaerobic Digester.

    Science.gov (United States)

    Hagen, Live H; Frank, Jeremy A; Zamanzadeh, Mirzaman; Eijsink, Vincent G H; Pope, Phillip B; Horn, Svein J; Arntzen, Magnus Ø

    2017-01-15

    In this study, we used multiple meta-omic approaches to characterize the microbial community and the active metabolic pathways of a stable industrial biogas reactor with food waste as the dominant feedstock, operating at thermophilic temperatures (60°C) and elevated levels of free ammonia (367 mg/liter NH 3 -N). The microbial community was strongly dominated (76% of all 16S rRNA amplicon sequences) by populations closely related to the proteolytic bacterium Coprothermobacter proteolyticus. Multiple Coprothermobacter-affiliated strains were detected, introducing an additional level of complexity seldom explored in biogas studies. Genome reconstructions provided metabolic insight into the microbes that performed biomass deconstruction and fermentation, including the deeply branching phyla Dictyoglomi and Planctomycetes and the candidate phylum "Atribacteria" These biomass degraders were complemented by a synergistic network of microorganisms that convert key fermentation intermediates (fatty acids) via syntrophic interactions with hydrogenotrophic methanogens to ultimately produce methane. Interpretation of the proteomics data also suggested activity of a Methanosaeta phylotype acclimatized to high ammonia levels. In particular, we report multiple novel phylotypes proposed as syntrophic acetate oxidizers, which also exert expression of enzymes needed for both the Wood-Ljungdahl pathway and β-oxidation of fatty acids to acetyl coenzyme A. Such an arrangement differs from known syntrophic oxidizing bacteria and presents an interesting hypothesis for future studies. Collectively, these findings provide increased insight into active metabolic roles of uncultured phylotypes and presents new synergistic relationships, both of which may contribute to the stability of the biogas reactor. Biogas production through anaerobic digestion of organic waste provides an attractive source of renewable energy and a sustainable waste management strategy. A comprehensive understanding

  18. Development of optimum conditions for modification of Kpautagi clay for application in petroleum refinery wastewater treatment

    Directory of Open Access Journals (Sweden)

    Matthew A. ONU

    2015-12-01

    Full Text Available Kautagi clay is a kaolin type deposit that is abundantly available in Niger State, Nigeria with potential for application in pollution control such as wastewater treatment. This study investigates the optimum conditions for modification of Kpautagi clay for application in refinery wastewater treatment. Sulphuric acid was used in the modification of the clay and the modification variables considered were acid concentration, activation time and temperature. To develop the optimum conditions for the modification variables, the sulphuric acid modified Kpautagi clay was applied in the treatment of refinery wastewater in column mode at a fixed flow rate and mass of adsorbent. The results obtained indicate that the optimum conditions for modification of Kpautagi clay for application in the treatment of petroleum refinery wastewater are: acid concentration of 4M; activation time of 120min and activation temperature of 100°C. Therefore, the optimum conditions developed in this study for modification of Kpautagi clay could be applied for improved performance in the treatment of petroleum refinery wastewater.

  19. Ability of industrial anaerobic ecosystems to produce methane from ethanol in psychrophilic, mesophilic and thermophilic conditions

    International Nuclear Information System (INIS)

    Mabala, Jojo Charlie

    2012-01-01

    potential for adaptation depended on the presence of very specific methanogenic Archaea populations. When placing the adapted ecosystems in temperatures different from the original temperature, only mesophilic ecosystems adapted to psychrophilic temperatures. As expected, specific methanogenic activity was always obtained at the original temperature of the ecosystem. Analysis of bacterial and archaeal communities at the end of the acclimation period revealed that acclimation of thermophilic and mesophilic ecosystems to lower temperatures only modified slightly the structure of microbial communities. On the other hand, more significant changes were obtained when the incubation temperature was increased in comparison to the original temperature of the ecosystem. In summary, the study of the effect of incubation temperature (5 deg. C to 55 deg. C) on the fermentation activity and microbial population structure is a good model for laboratory study to understand the impact of abiotic factor on the structural and functional dynamics of a complex microbial community. (author) [fr

  20. The optimum decision rules for the oddity task

    NARCIS (Netherlands)

    Versfeld, N.J.; Dai, H.; Green, D.M.

    1996-01-01

    This paper presents the optimum decision rule for an m-interval oddity task in which m-1 intervals contain the same signal and one is different or odd. The optimum decision rule depends on the degree of correlation among observations. The present approach unifies the different strategies that occur

  1. Optimum mobility’ facelift. Part 2 – the technique

    OpenAIRE

    Fanous, Nabil; Karsan, Naznin; Zakhary, Kristina; Tawile, Carolyne

    2006-01-01

    In the first of this two-part article on the ‘optimum mobility’ facelift, facial tissue mobility was analyzed, and three theories or mechanisms emerged: ‘intrinsic mobility’, ‘surgically induced mobility’ and ‘optimum mobility points’.

  2. Problem of determining optimum geological and technical measures

    Energy Technology Data Exchange (ETDEWEB)

    Osipov, G N; Roste, Z A; Salimzhanov, E S

    1968-01-01

    This article is concerned with the mathematical simulation of oilfield operation, particularly the use of linear programing to determine optimum conditions for exploitation of a field. The basic approach is to define the field operation by a series of equations, apply boundary conditions and through an iterative computer technique find optimum operating conditions. Application of the method to Tuimazy field is illustrated.

  3. Optimum material gradient composition for the functionally graded ...

    African Journals Online (AJOL)

    This study investigates the relation between the material gradient properties and the optimum sensing/actuation design of the functionally graded piezoelectric beams. Three-dimensional (3D) finite element analysis has been employed for the prediction of an optimum composition profile in these types of sensors and ...

  4. Optimum unambiguous discrimination of linearly independent pure state

    DEFF Research Database (Denmark)

    Pang, Shengshi; Wu, Shengjun

    2009-01-01

    be satisfied by the optimum solution in different situations. We also provide the detailed steps to find the optimum measurement strategy. The method and results we obtain are given a geometrical illustration with a numerical example. Furthermore, using these equations, we derive a formula which shows a clear...

  5. A Genetic System for the Thermophilic Acetogenic Bacterium Thermoanaerobacter kivui.

    Science.gov (United States)

    Basen, Mirko; Geiger, Irina; Henke, Laura; Müller, Volker

    2018-02-01

    Thermoanaerobacter kivui is one of the very few thermophilic acetogenic microorganisms. It grows optimally at 66°C on sugars but also lithotrophically with H 2 + CO 2 or with CO, producing acetate as the major product. While a genome-derived model of acetogenesis has been developed, only a few physiological or biochemical experiments regarding the function of important enzymes in carbon and energy metabolism have been carried out. To address this issue, we developed a method for targeted markerless gene deletions and for integration of genes into the genome of T. kivui The strain naturally took up plasmid DNA in the exponential growth phase, with a transformation frequency of up to 3.9 × 10 -6 A nonreplicating plasmid and selection with 5-fluoroorotate was used to delete the gene encoding the orotate phosphoribosyltransferase ( pyrE ), resulting in a Δ pyrE uracil-auxotrophic strain, TKV002. Reintroduction of pyrE on a plasmid or insertion of pyrE into different loci within the genome restored growth without uracil. We subsequently studied fructose metabolism in T. kivui The gene fruK (TKV_c23150) encoding 1-phosphofructosekinase (1-PFK) was deleted, using pyrE as a selective marker via two single homologous recombination events. The resulting Δ fruK strain, TKV003, did not grow on fructose; however, growth on glucose (or on mannose) was unaffected. The combination of pyrE as a selective marker and the natural competence of the strain for DNA uptake will be the basis for future studies on CO 2 reduction and energy conservation and their regulation in this thermophilic acetogenic bacterium. IMPORTANCE Acetogenic bacteria are currently the focus of research toward biotechnological applications due to their potential for de novo synthesis of carbon compounds such as acetate, butyrate, or ethanol from H 2 + CO 2 or from synthesis gas. Based on available genome sequences and on biochemical experiments, acetogens differ in their energy metabolism. Thus, there is an

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

    NARCIS (Netherlands)

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

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

  7. Microbial community changes in methanogenic granules during the transition from mesophilic to thermophilic conditions

    DEFF Research Database (Denmark)

    Zhu, Xinyu; Kougias, Panagiotis; Treu, Laura

    2017-01-01

    Upflow anaerobic sludge blanket (UASB) reactor is one of the most applied technologies for various high-strength wastewater treatments. The present study analysed the microbial community changes in UASB granules during the transition from mesophilic to thermophilic conditions. Dynamicity...

  8. 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

  9. 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

  10. Exceptional thermal stability and organic solvent tolerance of an esterase expressed from a thermophilic host

    DEFF Research Database (Denmark)

    Mei, Yuxia; Peng, Nan; Zhao, Shumiao

    2012-01-01

    , giving SisEstA. Upon Escherichia coli expression, only the thioredoxin-tagged EstA recombinant protein was soluble. The fusion protein was then purified, and removing the protein tag yielded EcSisEstA. Both forms of the thermophilic EstA enzyme were characterized. We found that SisEstA formed dimer...... that of EcSisEstA at 90°C. This indicated that thermophilic enzymes yielded from homologous expression should be better biocatalysts than those obtained from mesophilic expression.......A protein expression system recently developed for the thermophilic crenarchaeon Sulfolobus islandicus was employed to produce recombinant protein for EstA, a thermophilic esterase encoded in the same organism. Large amounts of protein were readily obtained by an affinity protein purification...

  11. 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

  12. Hydrogen production from carrot pulp by the extreme thermophiles Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana

    NARCIS (Netherlands)

    Vrije, de G.J.; Budde, M.A.W.; Lips, S.J.J.; Bakker, R.R.; Mars, A.E.; Claassen, P.A.M.

    2010-01-01

    Hydrogen was produced from carrot pulp hydrolysate, untreated carrot pulp and (mixtures of) glucose and fructose by the extreme thermophiles Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana in pH-controlled bioreactors. Carrot pulp hydrolysate was obtained after enzymatic hydrolysis

  13. Substrate and product inhibition of hydrogen production by the extreme thermophile, Caldicellulosiruptor saccharolyticus

    NARCIS (Netherlands)

    Niel, van E.W.J.; Claassen, P.A.M.; Stams, A.J.M.

    2003-01-01

    Substrate and product inhibition of hydrogen production during sucrose fermentation by the extremely thermophilic bacterium Caldicellulosiruptor saccharolyticus was studied. The inhibition kinetics were analyzed with a noncompetitive, nonlinear inhibition model. Hydrogen was the most severe

  14. Performance of thermophilic anaerobic digesters using inoculum mixes with enhanced methanogenic diversity

    KAUST Repository

    Ghanimeh, Sophia; El-Fadel, Mutasem; Saikaly, Pascal

    2017-01-01

    Reportedly, various mixes of seeds were quasi-randomly selected to startup anaerobic digesters. In contrast, this study examines the impact of inoculating thermophilic anaerobic digesters with a designed mix of non-acclimated seeds based

  15. What is the effect of optimum independent parameters on solar heating systems?

    International Nuclear Information System (INIS)

    Kaçan, Erkan; Ulgen, Koray; Kaçan, Erdal

    2015-01-01

    Highlights: • The efficiency effect of 4 independent parameters over the solar heating system are examined. • 3 of 4 independent parameters are found as decisive parameter for system design. • Maximum exergetic efficiency exceeded 11% at optimized process. • Maximum environmental efficiency reached up to 95% at optimized process. • The optimum outside temperature and solar radiation are found as 22 °C and 773 W/m"2 for all responses. - Abstract: Researchers are rather closely involved in Solar Combisystems recently, but there is lack of study that presents the optimum design parameters. Therefore, in this study the influence of the four major variables, namely; outside, inside temperature, solar radiation on horizontal surface and instantaneous efficiency of solar collector on the energetic, exergetic and environmental efficiencies of Solar Combisystems are investigated and system optimization is done by a combination of response surface methodology. Measured parameters and energetic–exergetic and environmental performance curves are found and statistical model is created parallel with the actual data. It is found that statistical model is significant and all “lack-of-fit” values are non-significant. Thus, it is proved that statistical model strongly represents the design model. Outside temperature, solar radiation on horizontal surface and instantaneous efficiency of solar collector are the decisive parameters for all responses but instantaneous efficiency of solar collector is not for environmental efficiency. Maximum exergetic efficiency exceeded 11%, maximum environmental efficiency reached up to 95% at optimized process. The optimum value of the outside temperature and solar radiation are found as 22 °C and 773 W/m"2 for all responses, on the other hand optimum collector efficiency is found around 60% for energetic and exergetic efficiency values. Inside temperature is not a decisive parameter for all responses.

  16. Improved cellulose conversion to bio-hydrogen with thermophilic bacteria and characterization of microbial community in continuous bioreactor

    International Nuclear Information System (INIS)

    Jiang, Hongyu; Gadow, Samir I.; Tanaka, Yasumitsu; Cheng, Jun; Li, Yu-You

    2015-01-01

    Thermophilic hydrogen fermentation of cellulose was evaluated by a long term continuous experiment and batch experiments. The continuous experiment was conducted under 55 °C using a continuously stirred tank reactor (CSTR) at a hydraulic retention time (HRT) of 10 day. A stable hydrogen yield of 15.4 ± 0.23 mol kg −1 of cellulose consumed was maintained for 190 days with acetate and butyrate as the main soluble byproducts. An analysis of the 16S rRNA sequences showed that the hydrogen-producing thermophilic cellulolytic microorganisms (HPTCM) were close to Thermoanaerobacterium thermosaccharolyticum, Clostridium sp. and Enterobacter cloacae. Batch experiment demonstrated that the highest H 2 producing activity was obtained at 55 °C and the ultimate hydrogen yield and the metabolic by-products were influenced greatly by temperatures. The effect of temperature variation showed that the activation energy for cellulose and glucose were estimated at 103 and 98.8 kJ mol −1 , respectively. - Highlights: • Continuous cellulosic-hydrogen fermentation was conducted at 55 °C. • Hydrogen yield was improved to 15.4 mol kg −1 of consumed-cellulose. • The cellulosic hydrogen bacteria were close to Clostridia and Enterobacter genus. • The mixed microflora produced H 2 within a wide range of temperatures (35 °C–65 °C). • Activation energy of cellulose and glucose were 103 and 98.8 kJ mol −1 , respectively

  17. Up-Streaming Process for Glucose Oxidase by Thermophilic Penicillium sp. in Shake Flask

    OpenAIRE

    Muhammad Mohsin JAVED; Aroosh SHABIR; Sana ZAHOOR; Ikram UL-HAQ

    2012-01-01

    The present study is concerned with the production of glucose oxidase (GOD) from thermophilic Penicillium sp. in 250 mL shake flask. Fourteen different strains of thermophilic Penicillium sp. were isolated from the soil and were screened for glucose oxidase production. IIBP-13 strain gave maximum extra-cellular glucose oxidase production as compared to other isolates. Effect of submerged fermentation in shaking and static conditions, different carbon sources and incubation period on the produ...

  18. Molecular diversity of thermophilic bacteria isolated from Pasinler hot spring (Erzurum, Turkey)

    OpenAIRE

    ADIGÜZEL, Ahmet; İNAN, Kadriye; ŞAHİN, Fikrettin; ARASOĞLU, Tulin; GÜLLÜCE, Medine

    2011-01-01

    The present study was conducted to determine the phenotypic and genotypic characterization of thermophilic bacteria isolated from Pasinler hot spring, Erzurum, Turkey. Fatty acid profiles, BOX PCR fingerprints, and 16S rDNA sequence data were used for the phenotypic and genotypic characterization of thermophilic bacteria. Totally 9 different bacterial strains were selected based on morphological, physiological, and biochemical tests. These strains were characterized by molecular tests includi...

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

    OpenAIRE

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

    2015-01-01

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

  20. Kinetics of Butyrate, Acetate, and Hydrogen Metabolism in a Thermophilic, Anaerobic, Butyrate-Degrading Triculture

    OpenAIRE

    Ahring, Birgitte K.; Westermann, Peter

    1987-01-01

    Kinetics of butyrate, acetate, and hydrogen metabolism were determined with butyrate-limited, chemostat-grown tricultures of a thermophilic butyrate-utilizing bacterium together with Methanobacterium thermoautotrophicum and the TAM organism, a thermophilic acetate-utilizing methanogenic rod. Kinetic parameters were determined from progress curves fitted to the integrated form of the Michaelis-Menten equation. The apparent half-saturation constants, Km, for butyrate, acetate, and dissolved hyd...

  1. Exact Optimum Design of Segmented Thermoelectric Generators

    Directory of Open Access Journals (Sweden)

    M. Zare

    2016-01-01

    Full Text Available A considerable difference between experimental and theoretical results has been observed in the studies of segmented thermoelectric generators (STEGs. Because of simplicity, the approximate methods are widely used for design and optimization of the STEGs. This study is focused on employment of exact method for design and optimization of STEGs and comparison of exact and approximate results. Thus, using new highly efficient thermoelectric materials, four STEGs are proposed to operate in the temperature range of 300 to 1300 kelvins. The proposed STEGs are optimally designed to achieve maximum efficiency. Design and performance characteristics of the optimized generators including maximum conversion efficiency and length of elements are calculated through both exact and approximate methods. The comparison indicates that the approximate method can cause a difference up to 20% in calculation of some design characteristics despite its appropriate results in efficiency calculation. The results also show that the maximum theoretical efficiency of 23.08% is achievable using the new proposed STEGs. Compatibility factor of the selected materials for the proposed STEGs is also calculated using both exact and approximate methods. The comparison indicates a negligible difference in calculation of compatibility factor, despite the considerable difference in calculation of reduced efficiency (temperature independence efficiency.

  2. Influence of initial pH on thermophilic anaerobic co-digestion of swine manure and maize stalk.

    Science.gov (United States)

    Zhang, Tong; Mao, Chunlan; Zhai, Ningning; Wang, Xiaojiao; Yang, Gaihe

    2015-01-01

    The contradictions between the increasing energy demand and decreasing fossil fuels are making the use of renewable energy the key to the sustainable development of energy in the future. Biogas, a renewable clean energy, can be obtained by the anaerobic fermentation of manure waste and agricultural straw. This study examined the initial pH value had obvious effect on methane production and the process in the thermophilic anaerobic co-digestion. Five different initial pH levels with three different manure ratios were tested. All digesters in different initial pH showed a diverse methane production after 35 days. The VFA/alkalinity ratio of the optimum reaction condition for methanogens activity was in the range of 0.1-0.3 and the optimal condition that at the 70% dung ratio and initial pH 6.81, was expected to achieve maximum total biogas production (146.32 mL/g VS). Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Properties of an amylase from thermophilic Bacillus SP. Propriedades de uma amilase de um termofílico Bacillus sp

    Directory of Open Access Journals (Sweden)

    Raquel Vieira de Carvalho

    2008-03-01

    Full Text Available alpha-Amylase production by thermophilic Bacillus sp strain SMIA-2 cultivated in liquid cultures containing soluble starch as a carbon source and supplemented with 0.05% whey protein and 0.2% peptone reached a maximum activity at 32 h, with levels of 37 U/mL. Studies on the amylase characterization revealed that the optimum temperature of this enzyme was 90ºC. The enzyme was stable for 1 h at temperatures ranging from 40-50ºC while at 90ºC, 66% of its maximum activity was lost. However, in the presence of 5 mM CaCl2, the enzyme was stable at 90ºC for 30 min and retained about 58% residual activity after 1 h. The optimum pH of the enzyme was found to be 8.5. After incubation of enzyme for 2 h at pH 9.5 and 11.0 was observed a decrease of about 6.3% and 16.5% of its original activity. At pH 6.0 the enzyme lost about 36% of its original activity. The enzyme was strongly inhibited by Co2+, Cu2+ and Ba2+, but less affected by Mg2+, Na+ and K+. In the presence of 2.0 M NaCl, 63% of amylase activity was retained after 2 h incubation at 45ºC. The amylase exhibited more than 70% activity when incubated for 1 h at 50ºC with sodium dodecyl sulphate. However, very little residual activity was obtained with sodium hypochlorite and with hydrogen peroxide the enzyme was completely inhibited. The compatibility of Bacillus sp SMIA-2 amylase with certain commercial detergents was shown to be good as the enzyme retained 86%, 85% and 75% of its activity after 20 min incubation at 50ºC in the presence of the detergent brands Omo®, Campeiro® and Tide®, respectively.A produção de alfa-amilase por um termofilico, Bacillus sp SMIA-2, cultivado em meio líquido contendo amido solúvel como fonte de carbono, alcançou uma atividade máxima de 37 U/mL em 32 horas. Estudos sobre a caracterização da amilase revelaram que a temperatura ótima desta enzima foi 90ºC. A enzima foi estável por 1 hora a temperaturas de 40 e 50ºC enquanto a 90ºC, 66% da atividade

  4. 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.

  5. Hybrid biogas upgrading in a two-stage thermophilic reactor

    DEFF Research Database (Denmark)

    Corbellini, Viola; Kougias, Panagiotis; Treu, Laura

    2018-01-01

    The aim of this study is to propose a hybrid biogas upgrading configuration composed of two-stage thermophilic reactors. Hydrogen is directly injected in the first stage reactor. The output gas from the first reactor (in-situ biogas upgrade) is subsequently transferred to a second upflow reactor...... (ex-situ upgrade), in which enriched hydrogenotrophic culture is responsible for the hydrogenation of carbon dioxide to methane. The overall objective of the work was to perform an initial methane enrichment in the in-situ reactor, avoiding deterioration of the process due to elevated pH levels......, and subsequently, to complete the biogas upgrading process in the ex-situ chamber. The methane content in the first stage reactor reached on average 87% and the corresponding value in the second stage was 91%, with a maximum of 95%. A remarkable accumulation of volatile fatty acids was observed in the first...

  6. 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

  7. Synthetic polyester-hydrolyzing enzymes from thermophilic actinomycetes.

    Science.gov (United States)

    Wei, Ren; Oeser, Thorsten; Zimmermann, Wolfgang

    2014-01-01

    Thermophilic actinomycetes produce enzymes capable of hydrolyzing synthetic polyesters such as polyethylene terephthalate (PET). In addition to carboxylesterases, which have hydrolytic activity predominantly against PET oligomers, esterases related to cutinases also hydrolyze synthetic polymers. The production of these enzymes by actinomycetes as well as their recombinant expression in heterologous hosts is described and their catalytic activity against polyester substrates is compared. Assays to analyze the enzymatic hydrolysis of synthetic polyesters are evaluated, and a kinetic model describing the enzymatic heterogeneous hydrolysis process is discussed. Structure-function and structure-stability relationships of actinomycete polyester hydrolases are compared based on molecular dynamics simulations and recently solved protein structures. In addition, recent progress in enhancing their activity and thermal stability by random or site-directed mutagenesis is presented. © 2014 Elsevier Inc. All rights reserved.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-09-16

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

  9. Characterisation of community structure of bacteria in parallel mesophilic and thermophilic pilot scale anaerobe sludge digesters.

    Science.gov (United States)

    Tauber, T; Berta, Brigitta; Székely, Anna J; Gyarmati, I; Kékesi, Katalin; Márialigeti, K; Tóth, Erika M

    2007-03-01

    The aim of the present work was to compare the microbial communities of a mesophilic and a thermophilic pilot scale anaerobe sludge digester. For studying the communities cultivation independent chemotaxonomical methods (RQ and PLFA analyses) and T-RFLP were applied. Microbial communities of the mesophilic and thermophilic pilot digesters showed considerable differences, both concerning the species present, and their abundance. A Methanosarcina sp. dominated the thermophilic, while a Methanosaeta sp. the mesophilic digester among Archaea. Species diversity of Bacteria was reduced in the thermophilic digester. Based on the quinone patterns in both digesters the dominance of sulphate reducing respiratory bacteria could be detected. The PLFA profiles of the digester communities were similar though in minor components characteristic differences were shown. Level of branched chain fatty acids is slightly lower in the thermophilic digester that reports less Gram positive bacteria. The relative ratio of fatty acids characteristic to Enterobacteriaceae, Bacteroidetes and Clostridia shows differences between the two digesters: their importance generally decreased under thermophilic conditions. The sulphate reducer marker (15:1 and 17:1) fatty acids are present in low quantity in both digesters.

  10. Comparative economic assessment of ethanol production under mesophilic and thermophilic conditions

    International Nuclear Information System (INIS)

    Mistry, P.B.

    1991-01-01

    Key technical factors affecting the economics of bioethanol production are critically analyzed with special reference to the relative merits of thermophilic and mesophilic fermentation. A number of novel process schemes to take advantage of thermophilic operation are discussed. Analysis of the capital and operating costs for a range of flowsheets then provides a basis for critical study. Estimates for thermophilic production are compared with those for a sugar cane based mesophilic process (using S. cerevisiae). For the thermophilic fermentation, the basic kinetic and yield constants are based on projected values for a strain of B. stearothermophilus. Compared to mesophilic operation, thermophilic operation results in reduced capital, operating and feed costs. The feed cost still accounts for a large proportion (75%) of the total production cost. However, on a feed-cost-free basis, a reduction in production cost of up to 32% could be realized by changing to thermophilic operation from existing yeast-based processes, after minor process modifications. 20 refs., 10 figs., 8 tabs

  11. Screening and characterization of thermo-active enzymes of biotechnological interest produced by thermophilic Bacillus isolated from hot springs in Tunisia.

    Science.gov (United States)

    Thebti, Wajdi; Riahi, Yosra; Gharsalli, Rawand; Belhadj, Omrane

    2016-01-01

    As part of the contribution to the global efforts in research of thermostable enzymes being of industrial interest, we focus on the isolation of thermophilic bacteria from Tunisian hot springs. Among the collection of 161 strains of thermophilic Bacillus isolated from different samples of thermal water in Tunisia, 20% are capable of growing at 100°C and the rest grow at 70°C or above. Preliminary activity tests on media supplemented with enzyme-substrates confirmed that 35 strains produced amylases, 37 - proteases, 43 - cellulases, 31 - xylanases and 37 - mannanases. The study of the effect of temperature on enzyme activity led to determination of the optimal temperatures of activities that vary between 60 and 100°C. Several enzymes were active at high temperatures (80, 90 and 100°C) and kept their activity even at 110°C. Several isolated strains producing enzymes with high optimal temperatures of activity were described for the first time in this study. Both strains B62 and B120 are producers of amylase, protease, cellulase, xylanase, and mannanase. The sequencing of 16S DNA identified isolated strains as Geobacillus kaustophillus, Aeribacillus pallidus, Geobacillus galactosidasus and Geobacillus toebii.

  12. Design of slurry bubble column reactors: novel technique for optimum catalyst size selection contractual origin of the invention

    Science.gov (United States)

    Gamwo, Isaac K [Murrysville, PA; Gidaspow, Dimitri [Northbrook, IL; Jung, Jonghwun [Naperville, IL

    2009-11-17

    A method for determining optimum catalyst particle size for a gas-solid, liquid-solid, or gas-liquid-solid fluidized bed reactor such as a slurry bubble column reactor (SBCR) for converting synthesis gas into liquid fuels considers the complete granular temperature balance based on the kinetic theory of granular flow, the effect of a volumetric mass transfer coefficient between the liquid and the gas, and the water gas shift reaction. The granular temperature of the catalyst particles representing the kinetic energy of the catalyst particles is measured and the volumetric mass transfer coefficient between the gas and liquid phases is calculated using the granular temperature. Catalyst particle size is varied from 20 .mu.m to 120 .mu.m and a maximum mass transfer coefficient corresponding to optimum liquid hydrocarbon fuel production is determined. Optimum catalyst particle size for maximum methanol production in a SBCR was determined to be in the range of 60-70 .mu.m.

  13. Optimum design of vaporizer fin with liquefied natural gas by numerical analysis

    International Nuclear Information System (INIS)

    Jeong, Hyo Min; Chung, Han Shik; Lee, Sang Chul; Kong, Tae Woo; Yi, Chung Seub

    2006-01-01

    Generally, the temperature drop under 0 .deg. C on vaporizer surface creates frozen dews. This problem seems to increase as the time progress and humidity rises. In addition, the frozen dews create frost deposition. Consequently, heat transfer on vaporizer decreases because frost deposition causes adiabatic condition. Therefore, it is very important to solve this problem. This paper aims to study of the optimum design of used vaporizer at local LNG station. In this paper, experimental results were compared with numerical results. Geometries of numerical and experimental vaporizers were identical. Studied parameters of vaporizer are angle between two fins (Φ) and fin thickness (TH F ). Numerical analysis results were presented through the correlations between the ice layer thickness (TH ICE ) on the vaporizer surface to the temperature distribution of inside vaporizer (T IN ), fin thickness (TH F ), and angle between two fins (Φ). Numerical result shows good agreement with experimental outcome. Finally, the correlations for optimum design of vaporizer are proposed on this paper

  14. Champagne Pool (New Zealand) Thermophiles Yield Insights into the Evolution of Microbial Arsenic Resistance

    Science.gov (United States)

    Hug, K.; Krikowa, F.; Morgan, X.; Maher, W. A.; Stott, M. B.; Moreau, J. W.

    2011-12-01

    Arsenic is a highly toxic metalloid typically enriched in geothermal waters due to aqueous weathering of arsenic-bearing minerals. Investigation of enzymatic pathways by which thermophilic microorganisms cope with toxic arsenic levels may yield insights into the evolution of arsenic resistance mechanisms on the early Earth. At Wai-O-Tapu in the Taupo Volcanic Zone on the North Island of New Zealand, hot springs with temperatures of 30-90°C and elemental sulfur concentrations (expressed as equivalent sulfate) from 340 to 850 mg/l establish a range of environmental conditions. Total arsenic concentrations varied from 0.083 mg/l to 56 mg/l. Arsenic speciation analysis elucidated various biogeochemical arsenic transformations occurring within different springs. For example, in the Alum Cliff spring oxidizing conditions (Eh = 225 mV) were expected to stabilize dissolved arsenate (AsO43-). However, HPLC-ICPMS analyses yielded dissolved arsenate and arsenite (AsO33-) concentrations of 0.25 mg/l versus 43.3 mg/l, respectively, and point towards microbial arsenate reduction as the likely mechanism for arsenic redox transformation. 16S rRNA gene cloning of Alum Cliff DNA showed a predominantly archaeal population with the dominant clone "AC1_A1" most closely related (99% sequence similarity, NCBI BLAST°) to the uncultured Sulfolobus clone "ChP_97P" found in Champagne Pool (Childs et al., 2008). The closest isolated relative to AC1_A1 is Sulfolobus tokodaii str. TW with a sequence similarity of 94%. Arsenic speciation measurements from the Alum Cliff spring suggest that clone AC1_A1 features the arsenate reduction resistance mechanism, and we hypothesize therefore that an arsC (homolog or analog) provides this functionality. The organic arsenic species monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), detected via HPLC-ICPMS at concentrations ranging from 1 μg/l to 12 μg/l in various springs, may also implicate microbial methyl-group transfers as an active

  15. Optimum input leads for cryogenic apparatus

    International Nuclear Information System (INIS)

    Der Nigohossian, G.

    1967-02-01

    The electrical leads used to introduce a current into a cryostat cause a heat influx due to thermal conduction and to Joule heating. It is very important to be able to minimize this flux. Theoretical calculation of optimized leads takes into account the varying heat and electrical conductivities of the leads as well as the heat exchange coefficient with the effluent gas. Practical results have been summarized in different tables which permit for a specific material i.e. copper, aluminium, brass, stainless steel with the intensity and end temperatures being known (i.e. 4,2 or 18,5 deg. K at the cold end; 77,295 or 320 deg. K at the warm end) to deduce the minimum heat flow and the length-cross section ratio of the optimized leads. A general method is indicated, which would allow to solve the same problem for other materials. (author) [fr

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

    DEFF Research Database (Denmark)

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

    2011-01-01

    The two-stage process for extreme thermophilic hydrogen and thermophilic methane production from wheat straw hydrolysate was investigated in up-flow anaerobic sludge bed (UASB) reactors. Specific hydrogen and methane yields of 89ml-H2/g-VS (190ml-H2/g-sugars) and 307ml-CH4/g-VS, respectively were...... energy of 13.4kJ/g-VS. Dominant hydrogen-producing bacteria in the H2-UASB reactor were Thermoanaerobacter wiegelii, Caldanaerobacter subteraneus, and Caloramator fervidus. Meanwhile, the CH4-UASB reactor was dominated with methanogens of Methanosarcina mazei and Methanothermobacter defluvii. The results...

  17. Retooling the ethanol industry: thermophilic anaerobic digestion of thin stillage for methane production and pollution prevention.

    Science.gov (United States)

    Schaefer, Scott H; Sung, Shihwu

    2008-02-01

    Anaerobic digestion of corn ethanol thin stillage was tested at thermophilic temperature (55 degrees C) with two completely stirred tank reactors. The thin stillage wastestream was organically concentrated with 100 g/L total chemical oxygen demand and 60 g/L volatiles solids and a low pH of approximately 4.0. Steady-state was achieved at 30-, 20-, and 15-day hydraulic retention times (HRTs) and digester failure at a 12-day HRT. Significant reduction of volatile solids was achieved, with a maximum reduction (89.8%) at the 20-day HRT. Methane yield ranged from 0.6 to 0.7 L methane/g volatile solids removed during steady-state operation. Effluent volatile fatty acids below 200 mg/L as acetic acid were achieved at 20- and 30-day HRTs. Ultrasonic pretreatment was used for one digester, although no significant improvement was observed. Ethanol plant natural gas consumption could be reduced 43 to 59% with the methane produced, while saving an estimated $7 to $17 million ($10 million likely) for a facility producing 360 million L ethanol/y.

  18. Biochemical and structural insights into xylan utilization by the thermophilic bacterium Caldanaerobius polysaccharolyticus.

    Science.gov (United States)

    Han, Yejun; Agarwal, Vinayak; Dodd, Dylan; Kim, Jason; Bae, Brian; Mackie, Roderick I; Nair, Satish K; Cann, Isaac K O

    2012-10-12

    Hemicellulose is the next most abundant plant cell wall component after cellulose. The abundance of hemicellulose such as xylan suggests that their hydrolysis and conversion to biofuels can improve the economics of bioenergy production. In an effort to understand xylan hydrolysis at high temperatures, we sequenced the genome of the thermophilic bacterium Caldanaerobius polysaccharolyticus. Analysis of the partial genome sequence revealed a gene cluster that contained both hydrolytic enzymes and also enzymes key to the pentose-phosphate pathway. The hydrolytic enzymes in the gene cluster were demonstrated to convert products from a large endoxylanase (Xyn10A) predicted to anchor to the surface of the bacterium. We further use structural and calorimetric studies to demonstrate that the end products of Xyn10A hydrolysis of xylan are recognized and bound by XBP1, a putative solute-binding protein, likely for transport into the cell. The XBP1 protein showed preference for xylo-oligosaccharides as follows: xylotriose > xylobiose > xylotetraose. To elucidate the structural basis for the oligosaccharide preference, we solved the co-crystal structure of XBP1 complexed with xylotriose to a 1.8-Å resolution. Analysis of the biochemical data in the context of the co-crystal structure reveals the molecular underpinnings of oligosaccharide length specificity.

  19. Direct bioconversion of brown algae into ethanol by thermophilic bacterium Defluviitalea phaphyphila.

    Science.gov (United States)

    Ji, Shi-Qi; Wang, Bing; Lu, Ming; Li, Fu-Li

    2016-01-01

    Brown algae are promising feedstocks for biofuel production with inherent advantages of no structural lignin, high growth rate, and no competition for land and fresh water. However, it is difficult for one microorganism to convert all components of brown algae with different oxidoreduction potentials to ethanol. Defluviitalea phaphyphila Alg1 is the first characterized thermophilic bacterium capable of direct utilization of brown algae. Defluviitalea phaphyphila Alg1 can simultaneously utilize mannitol, glucose, and alginate to produce ethanol, and high ethanol yields of 0.47 g/g-mannitol, 0.44 g/g-glucose, and 0.3 g/g-alginate were obtained. A rational redox balance system under obligate anaerobic condition in fermenting brown algae was revealed in D. phaphyphila Alg1 through genome and redox analysis. The excess reducing equivalents produced from mannitol metabolism were equilibrated by oxidizing forces from alginate assimilation. Furthermore, D. phaphyphila Alg1 can directly utilize unpretreated kelp powder, and 10 g/L of ethanol was accumulated within 72 h with an ethanol yield of 0.25 g/g-kelp. Microscopic observation further demonstrated the deconstruction process of brown algae cell by D. phaphyphila Alg1. The integrated biomass deconstruction system of D. phaphyphila Alg1, as well as its high ethanol yield, provided us an excellent alternative for brown algae bioconversion at elevated temperature.

  20. Cloning, Expression and Characterization of a Novel Thermophilic Polygalacturonase from Caldicellulosiruptor bescii DSM 6725

    Directory of Open Access Journals (Sweden)

    Yanyan Chen

    2014-04-01

    Full Text Available We cloned the gene ACM61449 from anaerobic, thermophilic Caldicellulosiruptor bescii, and expressed it in Escherichia coli origami (DE3. After purification through thermal treatment and Ni-NTA agarose column extraction, we characterized the properties of the recombinant protein (CbPelA. The optimal temperature and pH of the protein were 72 °C and 5.2, respectively. CbPelA demonstrated high thermal-stability, with a half-life of 14 h at 70 °C. CbPelA also showed very high activity for polygalacturonic acid (PGA, and released monogalacturonic acid as its sole product. The Vmax and Km of CbPelA were 384.6 U·mg−1 and 0.31 mg·mL−1, respectively. CbPelA was also able to hydrolyze methylated pectin (48% and 10% relative activity on 20%–34% and 85% methylated pectin, respectively. The high thermo-activity and methylated pectin hydrolization activity of CbPelA suggest that it has potential applications in the food and textile industry.