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Sample records for anaerobic thermophiles final

  1. Anaerobic thermophiles.

    Science.gov (United States)

    Canganella, Francesco; Wiegel, Juergen

    2014-01-01

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

  2. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Wiegel, J.

    1998-05-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Wiegel, J.

    1998-09-01

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

  5. Thermophilic anaerobic digestion for waste and wastewater treatment.

    NARCIS (Netherlands)

    Wiegant, W.M.

    1986-01-01

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

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

    Science.gov (United States)

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

    2010-03-01

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

  7. Status on Science and Application of Thermophilic Anaerobic Digestion

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær

    1994-01-01

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

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

    NARCIS (Netherlands)

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

    2009-01-01

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

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

    NARCIS (Netherlands)

    Lier, van J.B.

    1995-01-01

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

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

    NARCIS (Netherlands)

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

    2004-01-01

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

  11. Diversity and ecophysiological features of thermophilic carboxydotrophic anaerobes

    NARCIS (Netherlands)

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

    2009-01-01

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

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

    NARCIS (Netherlands)

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

    2004-01-01

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

  13. Startup and stability of thermophilic anaerobic digestion of OFMSW

    KAUST Repository

    El-Fadel, Mutasem E.

    2013-01-01

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

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

    DEFF Research Database (Denmark)

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

    2009-01-01

    The aim of this study was to enrich, characterize and identify strict anaerobic extreme thermophilic hydrogen (H-2) producers from digested household solid wastes. A strict anaerobic extreme thermophilic H-2 producing bacterial culture was enriched from a lab-scale digester treating household...... to the genera Bacillus and Clostridium. Relative abundance of the culture members, assessed by fluorescence in situ hybridization, were 87 +/- 5% and 13 +/- 5% for Bacillus and Clostridium, respectively. An extreme thermophilic, strict anaerobic, mixed microbial culture with H-2-producing potential was enriched...

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

    OpenAIRE

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

    2007-01-01

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

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

    Science.gov (United States)

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

    2010-12-01

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

  17. Innovative two-stage mesophilic/thermophilic anaerobic degradation of sonicated sludge: performances and energy balance.

    Science.gov (United States)

    Gianico, A; Braguglia, C M; Gallipoli, A; Mininni, G

    2015-05-01

    This study investigates for the first time, on laboratory scale, the possible application of an innovative enhanced stabilization process based on sequential mesophilic/thermophilic anaerobic digestion of waste-activated sludge, with low-energy sonication pretreatment. The first mesophilic digestion step was conducted at short hydraulic retention time (3-5 days), in order to favor volatile fatty acid production, followed by a longer thermophilic step of 10 days to enhance the bioconversion kinetics, assuring a complete pathogen removal. The high volatile solid removals, up to 55%, noticeably higher compared to the performances of a single-stage process carried out in same conditions, can guarantee the stability of the final digestate for land application. The ultrasonic pretreatment influenced significantly the fatty acid formation and composition during the first mesophilic step, improving consequently the thermophilic conversion of these compounds into methane. Methane yield from sonicated sludge digestion reached values up to 0.2 Nm(3)/kgVSfed. Positive energy balances highlighted the possible exploitation of this innovative two-stage digestion in place of conventional single-stage processes. PMID:24906832

  18. Strain and bioprocess improvement of a thermophilic anaerobe for the production of ethanol from wood

    OpenAIRE

    Herring, Christopher D; Kenealy, William R.; Joe Shaw, A.; Covalla, Sean F.; Olson, Daniel G; Zhang, Jiayi; Ryan Sillers, W.; Tsakraklides, Vasiliki; Bardsley, John S.; Rogers, Stephen R.; Thorne, Philip G.; Johnson, Jessica P.; Foster, Abigail; Shikhare, Indraneel D.; Klingeman, Dawn M

    2016-01-01

    Background The thermophilic, anaerobic bacterium Thermoanaerobacterium saccharolyticum digests hemicellulose and utilizes the major sugars present in biomass. It was previously engineered to produce ethanol at yields equivalent to yeast. While saccharolytic anaerobes have been long studied as potential biomass-fermenting organisms, development efforts for commercial ethanol production have not been reported. Results Here, we describe the highest ethanol titers achieved from T. saccharolyticum...

  19. 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.

  20. Hydrolysis and thermophilic anaerobic digestion of sewage sludge and organic fraction of municipal solid waste

    Energy Technology Data Exchange (ETDEWEB)

    Del Borghi, A.; Converti, A.; Palazzi, E.; Del Borghi, M. [Institute of Chemical and Process Engineering ``G.B. Bonino``, Genoa University, Via Opera Pia 15, 16145 Genoa (Italy)

    1999-06-01

    An attempt is presented and discussed to adapt a well-known process successfully employed in the U.S.A. for the simultaneous treatment of the organic fraction of municipal solid waste (MSWOF) and sewage sludge to the particular situation of water works in Italy. It consists of preliminary domestic grinding of MSWOF, its discharge into the sewer, screening, and final digestion of the resulting residue together with sewage sludge. In order to avoid extension work of the present activated sludge sections necessary to face the organic load increase, a fine screening is necessary, while the efficiency of anaerobic digestion can be improved by shifting the system from mesophilic (37 C) to thermophilic (55 C) conditions. The effects of thermal, chemical, and biological pretreatments of both MSWOF and sewage sludge on methane, carbon dioxide, and biogas productions are investigated either separately or jointly. During these pretreatments, volatile suspended solid (VSS) concentration remarkably decreased while soluble chemical oxygen demand (COD) increased as the result of the progressive hydrolysis of the polymeric materials present in the feed. Finally, the kinetic parameters of the hydrolysis of these materials are estimated and compared in order to provide useful information on the factors limiting the anaerobic digestion as well as to suggest the best way to carry out the process on a large scale. (orig.) With 8 figs., 7 tabs., 20 refs.

  1. Regularities of polymer substances transformation into methane by thermophilic anaerobic bacteria

    OpenAIRE

    V. І. Karpenko; L. S. Yastremska; І. G. Burun; Y. V. Lembey; O. S. Tatarchenko

    2006-01-01

    The paper shows the regularities of polymer substances transformation into methane by extracted thermophilic anaerobic bacteria. The sequence of substrate use by the methane generating bacteria corresponds to the energy efficiency of the methane genesis reactions as in the first place hydrogen is used and then acetate is. Combined cultivation of extracted different anaerobic cultures gives the opportunity to increase ethanol and hydrogen yield as well as the effectiveness of methane formation.

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

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

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

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

    DEFF Research Database (Denmark)

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

    2004-01-01

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

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

    NARCIS (Netherlands)

    Vogelaar, J.C.T.

    2002-01-01

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

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

    NARCIS (Netherlands)

    Henstra, A.M.; Stams, A.J.M.

    2011-01-01

    Carboxydothermus hydrogenoformans is a thermophilic strictly anaerobic bacterium that catalyses the water gas shift reaction, the conversion of carbon monoxide with water to molecular hydrogen and carbon dioxide. The thermodynamically favorable growth temperature, compared to existing industrial cat

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

    OpenAIRE

    Mashad, El, H.

    2003-01-01

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

  7. 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.

  8. Effects of total solids content on waste activated sludge thermophilic anaerobic digestion and its sludge dewaterability.

    Science.gov (United States)

    Wang, Tianfeng; Chen, Jie; Shen, Honglang; An, Dong

    2016-10-01

    The role of total solids content on sludge thermophilic anaerobic digestion was investigated in batch reactors. A range of total solids content from 2% to 10% was evaluated with two replicates. The lowest inhibitory concentration for free ammonia and total ammonia of sludge thermophilic anaerobic digestion was 110.9-171.4mg/L and 1313.1-1806.7mg/L, respectively. The volumetric biogas production rate increased with increasing of total solids content, but the corresponding biogas yield per gram volatile solid decreased. The result of normalized capillary suction time indicated that the dewaterability of digested sludge at high total solids content was poor, while solid content of sediment obtained by centrifuging sludge at 2000g for 10min increased with increasing of total solids content of sludge. The results suggest that thickened sludge mixed with dewatered sludge at an appropriate ratio could get high organic loading rate, high biogas yield and adequate dewatering effort. PMID:26897469

  9. Reductive Decouloristation of Dyes by Thermophilic Anaerobic Granular Sludge

    NARCIS (Netherlands)

    Bezerra Dos Santos, A.

    2005-01-01

    The colour removal achieved under anaerobic conditions is also called reductive decolourisation, which is composed of a biological part, i.e. the reducing equivalents are biologically generated, and a chemical part, i.e. the formed electrons reduce chemically the dyes. The overall objective of this

  10. The fate of methanol in thermophilic-anaerobic environments

    NARCIS (Netherlands)

    Paulo, P.L.

    2002-01-01

    Methanol is a simple C1-compound, which sustains a complex web of possible degradation routes under anaerobic conditions. Methanol can be the main pollutant in some specific wastewaters, but it is also a compound that may be formed under natural conditions, as intermediate in the decomposition of or

  11. Thermophilic anaerobic fermentation of olive pulp for hydrogen and methane production: modelling of the anaerobic digestion process

    DEFF Research Database (Denmark)

    Gavala, Hariklia N.; Skiadas, Ioannis V.; Ahring, Birgitte Kiær;

    2006-01-01

    The present study investigates the thermophilic biohydrogen and methane production from olive pulp, which is the semi-solid. residue coming from the two-phase processing of olives. It focussed on: a) production of methane from the raw olive pulp; b) anaerobic bio-production of hydrogen from...... were performed. The hydrogen potential of the olive pulp amounted to 1.6 mmole H-2 per g TS. The methane potential of the raw olive pulp and hydrogen-effluent was as high as 19 mmole CH4 per g TS suggesting that: a) olive pulp is a suitable substrate for methane production; and b) biohydrogen...

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

    Directory of Open Access Journals (Sweden)

    Anne M. Henstra

    2011-01-01

    Full Text Available 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 low levels of CO are reached. Here we study CO conversion and final CO levels in cultures of C. hydrogenoformans grown in batch cultures that were started with a 100% CO gas phase with and without removal of formed CO2. Final CO levels were 117 ppm without CO2 removal and below 2 ppm with CO2 removal. The Gibbs free energy change calculated with measured end concentrations and the detection of acetate suggest that C. hydrogenoformans shifted from a hydrogenogenic to an acetogenic metabolism.

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

    Energy Technology Data Exchange (ETDEWEB)

    Lier, J.B. van; Grolle, K.C.F.; Lettinga, G. (Wageningen Agricultural Univ. (Netherlands). Dept. of Environmental Technology); Stams, A.J.M. (Wageningen Agricultural Univ. (Netherlands). Dept. of Microbiology); Conway de Macario, E. (New York State Dept. of Health, Albany, NY (United States). Wadsworth Center for Laboratories and Research State Univ. of New York, Albany, NY (United States). School of Public Health)

    1992-04-01

    Fast start-up of thermophilic upflow anaerobic sludge bed (UASB) reactors was achieved at process temperatures of 46, 55 and 64deg C, using mesophilic granular sludge as inoculum and fatty acid mixtures as feed. The start-up was brought about by increasing the temperature of mesophilic UASB reactors in a single step, which initially led to a sharp drop in the methane-production rate. Thereafter, stable thermophilic methanogenesis was achieved within a period of 1 or 2 weeks depending on the temperature of operation. Mesophilic granules functioned initially as effective carrier material for thermophilic organisms. However, long-term operation led to disintegration of the granules, resulting in wash-out of thermophilic biomass. The temperature optima for acetotrophic methanogenic activity of the sludges cultivated at 46, 55 and 64deg C, were similar, but differed significantly from the temperature optimum of the mesophilic inoculum. All the sludges examined were dominated by Methanothrix-like rods. These could be distinguished by antigenic fingerprinting into two subpopulations, one predominant at 36deg C and the other predominant at 46deg C and above. (orig.).

  14. Study of thermophilic anaerobic cleaning systems; Studier av termofila anaeroba reningssystem

    Energy Technology Data Exchange (ETDEWEB)

    Boman, B.; Davisson, G.

    1994-11-01

    The aim of this study was to indicate how mesophile and thermophilic anaerobic systems differ in their capacity to degrade persistent organic compounds. The experiments were carried out in semi-batch lab.scale reactors working at 35, 55 and 70 degrees C and were evaluated by recording pH, COD, TSS, redox potential, fatty acids, gas production, methane concentration and the concentration of specific organic compounds. Totally, seven different reactors and four different specific organic compounds were used in this study. The microbial activity within the semi-batch reactors showed a pronounced tendency to oscillate in an irregular and unpredictable way. This behaviour stressed the difficulties in running the decided experiments. These experiences are unfortunately confirmed by many other investigators within the present field. The results do not indicate differences between mesophile and thermophilic anaerobic reactors in terms of `not degradable-degradable` but only as differences in degree of degradation rates. 6-chlorovanillin and 3,5-dinitrobenzoic acid showed increasing degradation rate in the thermophilic range while no differences could be detected for 4,5-dichloroguaiacol. In the case of {beta}-sitosterol the mesophile reference reactor crash. 14 refs, 6 figs, 3 tabs

  15. Start-up performances of dry anaerobic mesophilic and thermophilic digestions of organic solid wastes

    Institute of Scientific and Technical Information of China (English)

    LU Shu-guang; IMAI Tsuyoshi; UKITA Masao; SEKINE Masahiko

    2007-01-01

    Two dry anaerobic digestions of organic solid wastes were conducted for 6 weeks in a lab-scale batch experiment for investigating the start-up performances under mesophilic and thermophilic conditions. The enzymatic activities,i.e., β-glucosidase, β-glucosidase, N-α -benzoyl-L-argininamide (BAA)-hydrolysing protease, urease and phosphatase activities were analysed. The lower BAA-hydrolysing protease activity during the first 2-3 weeks was due to the inhibition of the low pH, but was enhanced simultaneously later with the pH increase. β-glucosidase activity showed the lowest values in weeks 1-2, and recovered simultaneously with the increase of BAA-hydrolysing protease activity. Acetic acid dominated most of the total VFAs in thermophilic digestion, while propionate and butyrate dominated in mesophilic digestion. Thermophilic digestion is confirmed more feasible for achieving better performance against misbalance, especially during the start-up period in a dry anaerobic digestion process.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-07-01

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

  17. Treatment efficiency and VFA composition of a thermophilic anaerobic contact reactor treating food industry wastewater

    International Nuclear Information System (INIS)

    The objective of this study was to examine the effects of organic loading rate and hydraulic retention time on volatile fatty acid composition and treatment efficiency of high rate thermophilic anaerobic contact reactor (TACR) treating potato-chips wastewaters. The operational performance of TACR was monitored from start-up by assessing chemical oxygen demand (COD) removal efficiencies, volatile fatty acid (VFA) production and biogas composition. The reactor was studied at different organic loading rates (OLRs) ranging from 0.6 to 8 kg COD/m3 d. The COD removal efficiencies were found to be 86-97% and the methane percentage of the biogas produced was 68-89% during the OLRs studied. The approximate methane yield was found to be 0.42 m3 CH4/kg CODremoved. The major intermediate products of anaerobic digestion were acetate, propionate, iso-butyrate, butyrate, iso-valerate, valerate, iso-caproate and caproate. The use of thermophilic anaerobic contact reactor offers a sustainable technology for the treatment of potato-chips wastewaters since high COD removal efficiencies and high methane percentage in the biogas produced can be attained even at high OLRs.

  18. Performance and methanogenic community of rotating disk reactor packed with polyurethane during thermophilic anaerobic digestion

    International Nuclear Information System (INIS)

    A newly developed anaerobic rotating disk reactor (ARDR) packed with polyurethane was used in continuous mode for organic waste removal under thermophilic (55 oC) anaerobic conditions. This paper reports the effects of the rotational speed on the methanogenic performance and community in an ARDR supplied with acetic acid synthetic wastewater as the organic substrate. The best performance was obtained from the ARDR with the rotational speed (ω) of 30 rpm. The average removal of dissolved organic carbon was 98.5%, and the methane production rate was 393 ml/l-reactor/day at an organic loading rate of 2.69 g/l-reactor/day. Under these operational conditions, the reactor had a greater biomass retention capacity and better reactor performance than those at other rotational speeds (0, 5 and 60 rpm). The results of 16S rRNA phylogenetic analysis indicated that the major methanogens in the reactor belonged to the genus Methanosarcina spp. The results of real-time polymerase chain reaction (PCR) analysis suggested that the cell density of methanogenic archaea immobilized on the polyurethane foam disk could be concentrated more than 2000 times relative to those in the original thermophilic sludge. Scanning electron microphotographs showed that there were more immobilized microbes at ω of 30 rpm than 60 rpm. A rotational speed on the outer layer of the disk of 6.6 m/min could be appropriate for anaerobic digestion using the polyurethane ARDR

  19. Treatment efficiency and VFA composition of a thermophilic anaerobic contact reactor treating food industry wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Sentuerk, E.; Ince, M. [Gebze Institute of Technology, Department of Environmental Engineering, Gebze, 41400, Kocaeli (Turkey); Onkal Engin, G., E-mail: guleda@gyte.edu.tr [Gebze Institute of Technology, Department of Environmental Engineering, Gebze, 41400, Kocaeli (Turkey)

    2010-04-15

    The objective of this study was to examine the effects of organic loading rate and hydraulic retention time on volatile fatty acid composition and treatment efficiency of high rate thermophilic anaerobic contact reactor (TACR) treating potato-chips wastewaters. The operational performance of TACR was monitored from start-up by assessing chemical oxygen demand (COD) removal efficiencies, volatile fatty acid (VFA) production and biogas composition. The reactor was studied at different organic loading rates (OLRs) ranging from 0.6 to 8 kg COD/m{sup 3} d. The COD removal efficiencies were found to be 86-97% and the methane percentage of the biogas produced was 68-89% during the OLRs studied. The approximate methane yield was found to be 0.42 m{sup 3} CH{sub 4}/kg COD{sub removed}. The major intermediate products of anaerobic digestion were acetate, propionate, iso-butyrate, butyrate, iso-valerate, valerate, iso-caproate and caproate. The use of thermophilic anaerobic contact reactor offers a sustainable technology for the treatment of potato-chips wastewaters since high COD removal efficiencies and high methane percentage in the biogas produced can be attained even at high OLRs.

  20. Conversion of hemicelluloses and D-xylose into ethanol by the use of thermophilic anaerobic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-05-01

    Ethanol is a CO{sub 2} neutral liquid fuel that can substitute the use of fossil fuels in the transportation sector, thereby reducing the CO{sub 2} emission to the atmosphere. CO{sub 2} emission is suspected to contribute significantly to the so-called greenhouse effect, the global heating. Substrates for production of ethanol must be cheap and plentiful. This can be met by the use of lignocellulosic biomass such as willow, wheat straw, hardwood and softwood. However, the complexity of these polymeric substrates and the presence of several types of carbohydrates (glucose, xylose, mannose, galactose, arabinose) require additional treatment to release the useful carbohydrates and ferment the major carbohydrates fractions. The costs related to the ethanol-production must be kept at a minimum to be price competitive compared to gasoline. Therefore all of the carbohydrates present in lignocellulose need to be converted into ethanol. Glucose can be fermented to ethanol by yeast strains such as Saccharomyces cerevisiae, which, however, is unable to ferment the other major carbohydrate fraction, D-xylose. Thermophilic anaerobic ethanol producing bacteria can be used for fermentation of the hemicelluloses fraction of lignocellulosic biomass. However, physiological studies of thermophilic anaerobic bacteria have shown that the ethanol yield decreases at increasing substrate concentration. The biochemical limitations causing this phenomenon are not known in detail. Physiological and biochemical studies of a newly characterized thermophilic anaerobic ethanol producing bacterium, Thermoanaerobacter mathranii, was performed. This study included extraction of intracellular metabolites and enzymes of the pentose phosphate pathway and glycolysis. These studies revealed several bottlenecks in the D-xylose metabolism. This knowledge makes way for physiological and genetic engineering of this strain to improve the ethanol yield and productivity at high concentration of D-xylose. (au)

  1. Mass and Energy Balances of Dry Thermophilic Anaerobic Digestion Treating Swine Manure Mixed with Rice Straw

    OpenAIRE

    Sheng Zhou; Jining Zhang; Guoyan Zou; Shohei Riya; Masaaki Hosomi

    2015-01-01

    To evaluate the feasibility of swine manure treatment by a proposed Dry Thermophilic Anaerobic Digestion (DT-AD) system, we evaluated the methane yield of swine manure treated using a DT-AD method with rice straw under different C/N ratios and solid retention time (SRT) and calculated the mass and energy balances when the DT-AD system is used for swine manure treatment from a model farm with 1000 pigs and the digested residue is used for forage rice production. A traditional swine manure trea...

  2. Macroscopic mass and energy balance of a pilot plant anaerobic bioreactor operated under thermophilic conditions.

    Science.gov (United States)

    Espinosa-Solares, Teodoro; Bombardiere, John; Chatfield, Mark; Domaschko, Max; Easter, Michael; Stafford, David A; Castillo-Angeles, Saul; Castellanos-Hernandez, Nehemias

    2006-01-01

    Intensive poultry production generates over 100,000 t of litter annually in West Virginia and 9 x 10(6) t nationwide. Current available technological alternatives based on thermophilic anaerobic digestion for residuals treatment are diverse. A modification of the typical continuous stirred tank reactor is a promising process being relatively stable and owing to its capability to manage considerable amounts of residuals at low operational cost. A 40-m3 pilot plant digester was used for performance evaluation considering energy input and methane production. Results suggest some changes to the pilot plant configuration are necessary to reduce power consumption although maximizing biodigester performance.

  3. Effect of oxygen on the microbial activities of thermophilic anaerobic biomass.

    Science.gov (United States)

    Pedizzi, C; Regueiro, L; Rodriguez-Verde, I; Lema, J M; Carballa, M

    2016-07-01

    Low oxygen levels (μgO2L(-1)) in anaerobic reactors are quite common and no relevant consequences are expected. On the contrary, higher concentrations could affect the process. This work aimed to study the influence of oxygen (4.3 and 8.8mgO2L(-1), respectively) on the different microbial activities (hydrolytic, acidogenic and methanogenic) of thermophilic anaerobic biomass and on the methanogenic community structure. Batch tests in presence of oxygen were conducted using specific substrates for each biological activity and a blank (with minimum oxygen) was included. No effect of oxygen was observed on the hydrolytic and acidogenic activities. In contrast, the methane production rate decreased by 40% in all oxygenated batches and the development of active archaeal community was slower in presence of 8.8mgO2L(-1). However, despite this sensitivity of methanogens to oxygen at saturation levels, the inhibition was reversible. PMID:27020398

  4. Performance optimization and validation of ADM1 simulations under anaerobic thermophilic conditions

    KAUST Repository

    Atallah, Nabil M.

    2014-12-01

    In this study, two experimental sets of data each involving two thermophilic anaerobic digesters treating food waste, were simulated using the Anaerobic Digestion Model No. 1 (ADM1). A sensitivity analysis was conducted, using both data sets of one digester, for parameter optimization based on five measured performance indicators: methane generation, pH, acetate, total COD, ammonia, and an equally weighted combination of the five indicators. The simulation results revealed that while optimization with respect to methane alone, a commonly adopted approach, succeeded in simulating methane experimental results, it predicted other intermediary outputs less accurately. On the other hand, the multi-objective optimization has the advantage of providing better results than methane optimization despite not capturing the intermediary output. The results from the parameter optimization were validated upon their independent application on the data sets of the second digester.

  5. Upflow anaerobic solid-state (UASS) digestion of horse manure: Thermophilic vs. mesophilic performance.

    Science.gov (United States)

    Böske, Janina; Wirth, Benjamin; Garlipp, Felix; Mumme, Jan; Van den Weghe, Herman

    2015-01-01

    Energetic use of complex lignocellulosic wastes has gained global interest. Thermophilic digestion of horse manure based on straw was investigated using the upflow anaerobic solid-state (UASS) process. Increasing the organic loading rate from 2.5 to 5.5gvsL(-)(1)d(-)(1) enhanced the average methane production rate from 0.387 to 0.687LCH4L(-)(1)d(-)(1), whereas the yield decreased from 154.8 to 124.8LCH4kgvs(-)(1). A single-stage and two-stage process design showed almost the same performance. Compared to prior experiments at mesophilic conditions, thermophilic conditions showed a significantly higher efficiency with an increase of 59.8% in methane yield and 58.1% in methane production rate. Additional biochemical methane potential (BMP) tests with two types of horse manure and four different bedding materials showed that wheat straw obtained the highest BMP. The results show that the thermophilic UASS process can be the key to an efficient energy recovery from straw-based manures.

  6. Upflow anaerobic solid-state (UASS) digestion of horse manure: Thermophilic vs. mesophilic performance.

    Science.gov (United States)

    Böske, Janina; Wirth, Benjamin; Garlipp, Felix; Mumme, Jan; Van den Weghe, Herman

    2015-01-01

    Energetic use of complex lignocellulosic wastes has gained global interest. Thermophilic digestion of horse manure based on straw was investigated using the upflow anaerobic solid-state (UASS) process. Increasing the organic loading rate from 2.5 to 5.5gvsL(-)(1)d(-)(1) enhanced the average methane production rate from 0.387 to 0.687LCH4L(-)(1)d(-)(1), whereas the yield decreased from 154.8 to 124.8LCH4kgvs(-)(1). A single-stage and two-stage process design showed almost the same performance. Compared to prior experiments at mesophilic conditions, thermophilic conditions showed a significantly higher efficiency with an increase of 59.8% in methane yield and 58.1% in methane production rate. Additional biochemical methane potential (BMP) tests with two types of horse manure and four different bedding materials showed that wheat straw obtained the highest BMP. The results show that the thermophilic UASS process can be the key to an efficient energy recovery from straw-based manures. PMID:25459798

  7. Start-up strategies for thermophilic anaerobic digestion of pig manure

    International Nuclear Information System (INIS)

    Sludge physicochemical composition, methane (CH4) yield, and methanogenic community structure and dynamics using quantitative real-time polymerase chain reaction were determined after start-up of anaerobic digestion of pig manure. Eight thermophilic continuous stirred anaerobic digesters were used during 126 days. Four management strategies were investigated: a feedless and a non-feedless period followed by a gradual or an abrupt addition of pig manure (two digesters per strategy). During the first 43 days, VFA (volatile fatty acids) accumulations and low CH4 yield were observed in all digesters. After this period, digesters recovered their initial status being propionic acid the last parameter to be re-established. Non-feedless digesters with an abrupt addition of pig manure showed the best performances (lower VFA accumulation and higher CH4 yield). Differences in microbial orders and dynamics, however, were less evident among treatments. Hydrogenotrophic methanogenesis, Methanomicrobiales first and Methanobacteriales second, was the dominant metabolic pathway in all digesters. Further research is needed to clarify the role and activity of hydrogenotrophic methanogens during the recovery start-up period and to identify the best molecular tools and methodologies to monitor microbial populations and dynamics reliably and accurately in anaerobic digesters. - Highlights: • Four start-up strategies for thermophilic anaerobic digestion of pig manure were tested. • Physicochemical composition, methane yield and methanogenic community were determined. • During the first 43 days, a decline in reactor's performance occurred. • The best start-up strategy was non-feedless with an abrupt addition of pig slurry. • Hydrogenotrophic methanogenesis was the dominant metabolic pathway

  8. Evaluation of two-phase thermophilic anaerobic methane fermentation for the treatment of garbage

    International Nuclear Information System (INIS)

    Municipal solid wastes (MSW) in Japan are generally incinerated. However, in recent years, garbage has been recognized as a renewable energy source. This has resulted in an increase in the use of biological processes, such as anaerobic digestion, to treat organic waste such as sewage sludge and garbage. The two phases of anaerobic digestion are the acidogenic phase and the methane producing phase. Both differ significantly in their nutritional and physiological requirements. This study evaluated the effectiveness of treating garbage with the two-phase thermophilic methane fermentation system (TPS). The performance of the acid fermentation phase in TPS was examined with particular reference to operational parameters such as pH, hydraulic retention time and organic loading rate on volatile fatty acid fermentation. It was shown that TPS was more efficient than the single-phase thermophilic methane fermentation system (SPS). Acidification control in the first stage resulted in better stability of methane fermentation in the second stage. VFA formation was optimized at a pH of 6. The recovery ratios of VFAs and methane were achieved in the range of 42 to 44 per cent and 88 to 91 per cent of garbage by high organic loading rate respectively. 12 refs., 6 tabs., 4 figs

  9. Effects of lipids on thermophilic anaerobic digestion and reduction of lipid inhibition upon addition of bentonite.

    Science.gov (United States)

    Angelidaki, I; Petersen, S P; Ahring, B K

    1990-07-01

    The effect of bentonite-bound oil on thermophilic anaerobic digestion of cattle manure was investigated. In digestor experiments, addition of oil was found to be inhibitory during start-up and the inhibitory effect was less pronounced when the oil was added in the form of bentonite-bound oil compared to when the oil was added alone. After adaptation of the digestors, very rapid degradation of oil was observed and more than 80% of the oil was degraded within a few hours after daily feeding. In batch experiments, glyceride trioleate was found to be inhibitory to thermophilic anaerobic digestion when the concentrations were higher than 2.0 g/l. However, addition of bentonite (a clay mineral) at concentrations of 0.15% and 0.45% was found to partly overcome this inhibition. Addition of calcium chloride in concentration of 3 mM (0.033% w/v) showed a similar positive effect on the utilization of oil, but the effect was lower than with bentonite. PMID:1366749

  10. 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

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

    Science.gov (United States)

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

    2014-09-01

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

  12. Thermophilic anaerobic digestion of sewage sludge: focus on the influence of the start-up. A review.

    Science.gov (United States)

    De la Rubia, M A; Riau, V; Raposo, F; Borja, R

    2013-12-01

    The thermophilic anaerobic digestion (TAD) of sewage sludge has often been found to be less stable than mesophilic treatment. In comparison to mesophilic digesters, thermophilic reactors treating sludge are generally characterized by relatively high concentrations of volatile fatty acids (VFA) in the effluent along with poor effluent quality, indicating a lower level of process stability. However, reviewing the literature related to the procedure for obtaining a thermophilic inoculum, it seems that most of the problems associated with the instability and the accumulation of organic intermediates are the result of the manner in which the thermophilic sludge has been obtained. In this paper, the different options available for obtaining an anaerobic digester operating at thermophilic temperature (55°C) have been reviewed. In this light, rapid heating to the target temperature followed by the development of thermophilic microorganisms, which can be determined by VFA dropping to ≤ 500 mg acetic acid L(-1) before increasing the organic loading rate (OLR), has been determined the most suitable means of establishing TAD.

  13. Formation of metabolites during biodegradation of linear alkylbenzene sulfonate in an upflow anaerobic sludge bed reactor under thermophilic conditions

    DEFF Research Database (Denmark)

    Mogensen, Anders Skibsted; Ahring, Birgitte Kiær

    2002-01-01

    Biodegradation of linear alkylbenzene sulfonate (LAS) was shown in an upflow anaerobic sludge blanket reactor under thermophilic conditions. The reactor was inoculated with granular biomass and fed with a synthetic medium and 3 mumol/L of a mixture of LAS with alkylchain length of 10 to 13 carbon...

  14. Enhancing the Electron Transfer Capacity and Subsequent Color Removal in Bioreactors by Applying Thermophilic Anaerobic Treatment and Redox Mediators

    NARCIS (Netherlands)

    Santos, dos A.B.; Traverse, J.; Cervantes, F.J.; Lier, van J.B.

    2005-01-01

    The effect of temperature, hydraulic retention time (HRT) and the redox mediator anthraquinone-2,6-disulfonate (AQDS), on electron transfer and subsequent color removal from textile wastewater was assessed in mesophilic and thermophilic anaerobic bioreactors. The results clearly show that compared w

  15. The contribution of fermentative bacteria and methanogenic archaea to azo dye reduction by a thermophilic anaerobic consortium

    NARCIS (Netherlands)

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

    2006-01-01

    The contribution of fermentative bacteria and methanogenic archaea to azo dye reduction by a thermophilic anaerobic consortium was studied. Additionally, the effects of different electron-donating substrates and the redox mediator riboflavin on dye reduction were assessed by using either a methanoge

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

    NARCIS (Netherlands)

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

    2004-01-01

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

  17. Conversion of hemicellulose and D-xylose into ethanol by the use of thermophilic anaerobic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, Peter

    1998-02-01

    Ethanol is a CO{sub 2} neutral liquid fuel that can substitute the use of fossil fuels in the transportation sector, thereby reducing the CO{sub 2} emission to the atmoshpere. CO{sub 2} emission is suspected to contribute significantly to the so-called greenhouse effect, the global heating. Substrates for production of ethanol must be cheap and plentiful. This can be met by the use of lignocellulosic biomass such as willow, wheat straw, hardwood and softwood. However, the complexity of these polymeric substrates and the presence of several types of carbohydrates (glucose, xylose, mannose, galactose, arabinose) require additional treatment to release the useful carbohydrates and ferment the major carbohydrates fractions. The costs related to the ethanol-production must be kept at a minimum to be price competitive compared to gasoline. Therefore all of the carbohydrates present in lignocellulose need to be converted into ethanol. Glucose can be fermented to ethanol by yeast strains such as Saccharomyces cerevisiae, which, however, is unable to ferment the other major carbohydrate fraction, D-xylose. The need for a microorganism able to ferment D-xylose is therefore apparent. Thermophilic anaerobic ethanol producing bacteria can therefore be considered for fermentation of D-xylose. Screening of 130 thermophilic anaerobic bacterial strains, from hot-springs, mesophilic and thermophilic biogas plants, paper pulp industries and brewery waste, were examined for production of ethanol from D-xylose and wet-oxidized hemicellulose hydrolysate. Several strains were isolated and one particular strain was selected for best performance during the screening test. This strain was characterized as a new species, Thermoanaerobacter mathranii. However, the ethanol yield on wet-oxidized hemicellulose hydrolysate was not satisfactory. The bacterium was adapted by isolation of mutant strains, now resistant to the inhibitory compounds present in the hydrolysate. Growth and ethanol yield

  18. Mesophilic and thermophilic anaerobic co-digestion of abattoir wastewater and fruit and vegetable waste in anaerobic sequencing batch reactors.

    Science.gov (United States)

    Bouallagui, Hassib; Rachdi, Boutheina; Gannoun, Hana; Hamdi, Moktar

    2009-06-01

    Anaerobic co-digestion of fruit and vegetable waste (FVW) and abattoir wastewater (AW) was investigated using anaerobic sequencing batch reactors (ASBRs). The effects of hydraulic retention time (HRT) and temperature variations on digesters performances were examined. At both 20 and 10 days biogas production for co-digestion was greater thanks to the improved balance of nutrients. The high specific gas productions for the different digestion processes were 0.56, 0.61 and 0.85 l g(-1) total volatile solids (TVS) removal for digesters treating AW, FVW and AW + FVW, respectively. At an HRT of 20 days, biogas production rates from thermophilic digesters were higher on average than from mesophilic AW, FVW and AW + FVW digestion by 28.5, 44.5 and 25%, respectively. However, at 10 days of HRT results showed a decrease of biogas production rate for AW and AW + FVW digestion processes due to the high amount of free ammonia at high organic loading rate (OLR).

  19. Cassava Stillage Treatment by Thermophilic Anaerobic Continuously Stirred Tank Reactor (CSTR)

    Science.gov (United States)

    Luo, Gang; Xie, Li; Zou, Zhonghai; Zhou, Qi

    2010-11-01

    This paper assesses the performance of a thermophilic anaerobic Continuously Stirred Tank Reactor (CSTR) in the treatment of cassava stillage under various organic loading rates (OLRs) without suspended solids (SS) separation. The reactor was seeded with mesophilic anaerobic granular sludge, and the OLR increased by increments to 13.80 kg COD/m3/d (HRT 5d) over 80 days. Total COD removal efficiency remained stable at 90%, with biogas production at 18 L/d (60% methane). Increase in the OLR to 19.30 kg COD/m3/d (HRT 3d), however, led to a decrease in TCOD removal efficiency to 79% due to accumulation of suspended solids and incomplete degradation after shortened retention time. Reactor performance subsequently increased after OLR reduction. Alkalinity, VFA and pH levels were not significantly affected by OLR variation, indicating that no additional alkaline or pH adjustment is required. More than half of the SS in the cassava stillage could be digested in the process when HRT was 5 days, which demonstrated the suitability of anaerobic treatment of cassava stillage without SS separation.

  20. Ultrasound-mediated DNA transformation in thermophilic gram-positive anaerobes.

    Directory of Open Access Journals (Sweden)

    Lu Lin

    Full Text Available BACKGROUND: Thermophilic, Gram-positive, anaerobic bacteria (TGPAs are generally recalcitrant to chemical and electrotransformation due to their special cell-wall structure and the low intrinsic permeability of plasma membranes. METHODOLOGY/PRINCIPAL FINDINGS: Here we established for any Gram-positive or thermophiles an ultrasound-based sonoporation as a simple, rapid, and minimally invasive method to genetically transform TGPAs. We showed that by applying a 40 kHz ultrasound frequency over a 20-second exposure, Texas red-conjugated dextran was delivered with 27% efficiency into Thermoanaerobacter sp. X514, a TGPA that can utilize both pentose and hexose for ethanol production. Experiments that delivered plasmids showed that host-cell viability and plasmid DNA integrity were not compromised. Via sonoporation, shuttle vectors pHL015 harboring a jellyfish gfp gene and pIKM2 encoding a Clostridium thermocellum β-1,4-glucanase gene were delivered into X514 with an efficiency of 6x10(2 transformants/µg of methylated DNA. Delivery into X514 cells was confirmed via detecting the kanamycin-resistance gene for pIKM2, while confirmation of pHL015 was detected by visualization of fluorescence signals of secondary host-cells following a plasmid-rescue experiment. Furthermore, the foreign β-1,4-glucanase gene was functionally expressed in X514, converting the host into a prototypic thermophilic consolidated bioprocessing organism that is not only ethanologenic but cellulolytic. CONCLUSIONS/SIGNIFICANCE: In this study, we developed an ultrasound-based sonoporation method in TGPAs. This new DNA-delivery method could significantly improve the throughput in developing genetic systems for TGPAs, many of which are of industrial interest yet remain difficult to manipulate genetically.

  1. ATP as an indicator of biomass activity in thermophilic upflow anaerobic sludge blanket reactor

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This work investigated the biomass activity in a thermophilic upflow anaerobic sludge blanket (UASB) reactor of wastewater treatment. Synthetic textile wastewater with pH 10-11, COD level of 2000-3000 mg/L was tested. Cellular adenosine triphosphate (ATP) in volatile solids (VS; mg ATP/gVS) was measured and expressed as specific ATP content to compare the biomass activity in up zone and lower zone in UASB reactor. The result shows that the specific ATP content based on total volatile solids (VS)in lower zone (0. 046 mgATP/gVS average) is much lower than that in up zone (0.62 mgATP/gVS average) due to high content of inactive biomass and high pH in lower zone. The SATP in up zone increases as HRT increases and approaches to a maximum value of 0.85 mgATP/gVS at HRT of 7h, then decreases. It shows most of the total VS in up zone represent active bacterial biomass at HRT of 7h. Rate of subtract utilization is directly related to the activity of microorganisms in the reactor. The effect of HRT on SATP in lower zone is not as significant as on SATP in up zone. The buffer capacity of the thermophilic UASB reactor is very good. It is the activity of sludge granules in lower zone that give the UASB reactor such a good buffer capacity to the inlet high pH.

  2. Strategies for recovering inhibition caused by long chain fatty acids on anaerobic thermophilic biogas reactors

    DEFF Research Database (Denmark)

    Palatsi, J.; Laureni, M.; Andres, M.V.;

    2009-01-01

    and reducing the bioavailable LCFA concentration, were found to be the best recovery strategies, improving the recovery time from 10 to 2 days, in semi-continuously fed systems. Moreover, acclimatization was introduced by repeated inhibition and process recovery. The subsequent exposure of the anaerobic......Long chain fatty acids (LCFA) concentrations over 1.0 g L1 were inhibiting manure thermophilic digestion, in batch and semi-continuous experiments, resulting in a temporary cease of the biogas production. The aim of the work was to test and evaluate several recovery actions, such as reactor feeding...... patterns, dilution and addition of adsorbents, in order to determine the most appropriate strategy for fast recovery of the reactor activity in manure based plants inhibited by LCFA. Dilution with active inoculum for increasing the biomass/LCFA ratio, or addition of adsorbents for adsorbing the LCFA...

  3. Anaerobic digestibility of Scenedesmus obliquus and Phaeodactylum tricornutum under mesophilic and thermophilic conditions

    International Nuclear Information System (INIS)

    Highlights: ► We investigate the digestion of two algae biomasses in hybrid flow-through reactors. ► We determine the bio-methane potential of these biomasses through batch assays. ► Conversion efficiencies of 20–50% with an HRT of 2.2 days are possible. ► We valorise microalgae biomass by anaerobic digestion in a high rate reactor. -- Abstract: Two types of non-axenic algal cultures, one dominated by the freshwater microalgae Scenedesmus obliquus and the other by the marine microalgae Phaeodactylum tricornutum, were cultivated in two types of simple photobioreactor systems. The production rates, expressed on dry matter (DM) basis, were in the order of 0.12 and 0.18 g DM L−1 d−1 for S. obliquus and P. tricornutum respectively. The biogas potential of algal biomass was assessed by performing standardized batch digestion as well as digestion in a hybrid flow-through reactor (combining a sludge blanket and a carrier bed), the latter under mesophilic and thermophilic conditions. Biomethane potential assays revealed the ultimate methane yield (B0) of P. tricornutum biomass to be about a factor of 1.5 higher than that of S. obliquus biomass, i.e. 0.36 and 0.24 L CH4 g−1 volatile solids (VS) added respectively. For S. obliquus biomass, the hybrid flow-through reactor tests operated at volumetric organic loading rate (Bv) of 2.8 gVS L−1 d−1 indicated low conversion efficiencies ranging between 26–31% at a hydraulic retention time (HRT) of 2.2 days for mesophilic and thermophilic conditions respectively. When digesting P. tricornutum at a Bv of 1.9 gVS L−1 d−1 at either mesophilic or thermophilic conditions and at an HRT of 2.2 days, an overall conversion efficiency of about 50% was obtained. This work indicated that the hydrolysis of the algae cells is limiting the anaerobic processing of intensively grown S. obliquus and P. tricornutum biomass.

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

    Science.gov (United States)

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

    2009-08-01

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

  5. Anaerobic fermentation of agricultural residue: potential for improvement and implementation. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Jewell, W. J.; Capener, H. R.; Dell& #x27; orto, S.

    1978-02-01

    The results of studies designed to evaluate the potential of rapidly improving the technology of anaerobic fermentation of agricultural residues and methods of implementing it in existing agricultural operations are reported. The main objectives of this study were to: identify simple and low cost anaerobic fermentor design criteria that would be appropriate in small agricultural operations, develop high rate fermentor concepts that would enable multiple product recovery from the reactor, expand the information base particularly in the area of temperature influence on the process, and to review sociological and economic issues relating to implementation of fermentation technology. This study has identified several major anaerobic fermentation concepts which illustrate that the technology may be rapidly improved. A simple reactor design utilizing an unmixed plug flow concept was shown to be comparable to the more complex completely mixed reactor when using dairy cow residue. A high rate thermophilic reactor designed to encourage flotation of particulate solids illustrated that liquid, solid, and gaseous products can be generated within the anaerobic fermentor thus eliminating an additional dewatering unit process. A third reactor concept involved extension of the anaerobic attached microbial film expanded bed to the treatment of cow manure slurries. A high rate of methane generation was recorded. Comprehensive thermophilic fermentation studies (60/sup 0/C) indicated that the increased temperature resulted in little improvement in total quantity or the rate of yield of gas over that obtained with mesophilic fermentation with reactor retention periods greater than 10 days. Finally, other areas where preliminary date were obtained are noted.

  6. Fate of selected emerging micropollutants during mesophilic, thermophilic and temperature co-phased anaerobic digestion of sewage sludge.

    Science.gov (United States)

    Samaras, Vasilios G; Stasinakis, Athanasios S; Thomaidis, Nikolaos S; Mamais, Daniel; Lekkas, Themistokles D

    2014-06-01

    The removal of endocrine disrupting compounds (EDCs) and non-steroidal anti-inflammatory drugs (NSAIDs) was studied in three lab-scale anaerobic digestion (AD) systems; a single-stage mesophilic, a single-stage thermophilic and a two-stage thermophilic/mesophilic. All micropollutants underwent microbial degradation. High removal efficiency (>80%) was calculated for diclofenac, ibuprofen, naproxen and ketoprofen; whereas triclosan, bisphenol A and the sum of nonylphenol (NP), nonylphenol monoethoxylate (NP1EO) and nonylphenol diethoxylate were moderately removed (40-80%). NSAIDs removal was not affected by the type of AD system used; whereas slightly higher EDCs removal was observed in two-stage system. In this system, most microcontaminants were removed in thermophilic digester. Biotransformation of NP1EO and NP was affected by the temperature applied to bioreactors. Under mesophilic conditions, higher removal of NP1EO and accumulation of NP was noticed; whereas the opposite was observed under thermophilic conditions. For most analytes, higher specific removal rates were calculated under thermophilic conditions and 20 days SRT. PMID:24768891

  7. Semi-continuous solid substrate anaerobic reactors for H{sub 2} production from organic waste: Mesophilic versus thermophilic regime

    Energy Technology Data Exchange (ETDEWEB)

    Valdez-Vazquez, Idania; Rios-Leal, Elvira; Esparza-Garcia, Fernando; Poggi-Varaldo, Hector M. [CINVESTAV-IPN, Department Biotechnology and Bioengineering, Environmental Biotechnology, P.O. Box 14-740, Mexico D.F. 07000 (Mexico); Cecchi, Franco [Universita degli Studi di Verona, Verona (Italy)

    2005-11-01

    We evaluated the influence of the operation temperature (mesophilic vs. thermophilic regime) of semicontinuous, acidogenic solid substrate anaerobic digestion (A-SSAD) of the organic fraction of municipal solid waste (OFMSW) at lab scale. The H{sub 2} percentage was higher in the thermophilic regime than in the mesophilic operation (58% and 42%, respectively). The H{sub 2} yield of thermophilic A-SSAD was significantly higher than in our mesophilic reactors (360 vs. 165NmL H{sub 2}/g VS{sub rem}) and other studies reported in the literature (range of 62-180mL/g VS). Mesophilic A-SSAD showed a yield of 37% of the maximum yield based on 4molH{sub 2}/mol hexose, while thermophilic A-SSAD exhibited a yield of 80% of the maximum yield. This result is similar to works with pure cultures of extremophile microorganisms where H{sub 2} yields of 83% of the maximum were reported. We found higher concentrations of acetic acid in the digestates of thermophilic A-SSAD, while butyrate was in higher proportion in mesophilic A-SSAD spent solids. The moderate-to-high yields obtained with the semicontinuous process used in this work are in disagreement with previous reports claiming that batch and semicontinuous processes are less efficient than continuous ones. (author)

  8. Thermophilic Anaerobic Biodegradation of [14C]Lignin, [14C]Cellulose, and [14C]Lignocellulose Preparations

    OpenAIRE

    Benner, Ronald; Hodson, Robert E.

    1985-01-01

    Thermophilic (55°C) anaerobic enrichment cultures were incubated with [14C-lignin]lignocellulose, [14C-polysaccharide]lignocellulose, and kraft [14C]lignin prepared from slash pine, Pinus elliottii, and 14C-labeled preparations of synthetic lignin and purified cellulose. Significant but low percentages (2 to 4%) of synthetic and natural pine lignin were recovered as labeled methane and carbon dioxide during 60-day incubations, whereas much greater percentages (13 to 23%) of kraft lignin were ...

  9. 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...

  10. Enhancement of thermophilic anaerobic digestion of thickened waste activated sludge by combined microwave and alkaline pretreatment

    Institute of Scientific and Technical Information of China (English)

    Yongzhi Chi; Yuyou Li; Xuening Fei; Shaopo Wang; Hongying Yun

    2011-01-01

    Pretreatment of thickened waste activated sludge (TWAS) by combined microwave and alkaline pretreatment (MAP) was studied to improve thermophilic anaerobic digestion efficiency.Uniform design was applied to determine the combination of target temperature (110-210℃),microwave holding time (1-51 min),and NaOH dose (0-2.5 g NaOH/g suspended solids (SS)) in terms of their effect on volatile suspended solids (VSS) solubilization.Maximum solubilization ratio (85.1%) of VSS was observed at 210℃ with 0.2 g-NaOH/g-SS and 35 min holding time.The effects of 12 different pretreatment methods were investigated in 28 thermophilic batch reactors by monitoring cumulative methane production (CMP).Improvements in methane production in the TWAS were directly related to the microwave and alkaline pretreatment of the sludge.The highest CMP was a 27% improvement over the control.In spite of the increase in soluble chemical oxygen demand concentration and the decrease in dewaterability of digested sludge,a semi-continuous thennophilic reactor fed with pretreated TWAS without neutralization (at 170℃ with 1 rain holding time and 0.05 g NaOH/g SS) was stable and functioned well,with volatile solid (VS) and total chemical oxygen demand (TCOD) reductions of 28% and 18%,respectively,which were higher than those of the control system.Additionally,methane yields (L@STP/g-CODadded,at standard temperature and pressure (STP) conditions of 0℃ and 101.325 kPa) and (L@STP/g VSadded) increased by 17% and 13%,respectively,compared to the control reactor.

  11. 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

  12. Elucidation of the thermophilic phenol biodegradation pathway via benzoate during the anaerobic digestion of municipal solid waste.

    Science.gov (United States)

    Hoyos-Hernandez, Carolina; Hoffmann, Marieke; Guenne, Angeline; Mazeas, Laurent

    2014-02-01

    Anaerobic digestion makes it possible to valorize municipal solid waste (MSW) into biogas and digestate which are, respectively, a renewable energy source and an organic amendment for soil. Phenols are persistent pollutants present in MSW that can inhibit the anaerobic digestion process and have a toxic effect on microbiota if they are applied to soil together with digestate. It is then important to define the operational conditions of anaerobic digestion which allow the complete degradation of phenol. In this context, the fate of phenol during the anaerobic digestion of MSW at 55°C was followed using an isotopic tracing approach ((13)C6-phenol) in experimental microcosms with inoculum from an industrial thermophilic anaerobic digester. With this approach, it was possible to demonstrate the complete phenol biodegradation into methane and carbon dioxide via benzoate. Benzoate is known to be a phenol metabolite under mesophilic conditions, but in this study it was found for the first time to be a phenol degradation product at thermophilic temperature.

  13. Elucidation of the thermophilic phenol biodegradation pathway via benzoate during the anaerobic digestion of municipal solid waste.

    Science.gov (United States)

    Hoyos-Hernandez, Carolina; Hoffmann, Marieke; Guenne, Angeline; Mazeas, Laurent

    2014-02-01

    Anaerobic digestion makes it possible to valorize municipal solid waste (MSW) into biogas and digestate which are, respectively, a renewable energy source and an organic amendment for soil. Phenols are persistent pollutants present in MSW that can inhibit the anaerobic digestion process and have a toxic effect on microbiota if they are applied to soil together with digestate. It is then important to define the operational conditions of anaerobic digestion which allow the complete degradation of phenol. In this context, the fate of phenol during the anaerobic digestion of MSW at 55°C was followed using an isotopic tracing approach ((13)C6-phenol) in experimental microcosms with inoculum from an industrial thermophilic anaerobic digester. With this approach, it was possible to demonstrate the complete phenol biodegradation into methane and carbon dioxide via benzoate. Benzoate is known to be a phenol metabolite under mesophilic conditions, but in this study it was found for the first time to be a phenol degradation product at thermophilic temperature. PMID:24238916

  14. Continuous live cell imaging of cellulose attachment by microbes under anaerobic and thermophilic conditions using confocal microscopy

    Institute of Scientific and Technical Information of China (English)

    Zhi-Wu Wang; Seung-Hwan Lee; James G.Elkins; Yongchao Li; Scott Hamilton-Brehm; Jennifer L.Morrell-Falvey

    2013-01-01

    Live cell imaging methods provide important insights into the dynamics of cellular processes that cannot be derived easily from population-averaged datasets.In the bioenergy field,much research is focused on fermentation of cellulosic biomass by thermophilic microbes to produce biofuels; however,little effort is dedicated to the development of imaging tools to monitor this dynamic biological process.This is,in part,due to the experimental challenges of imaging ceils under both anaerobic and thermophilic conditions.Here an imaging system is described that integrates confocal microscopy,a flow cell device,and a lipophilic dye to visualize cells.Solutions to technical obstacles regarding suitable fluorescent markers,photodamage during imaging,and maintenance of environmental conditions during imaging are presented.This system was utilized to observe cellulose colonization by Clostridium thermocellum under anaerobic conditions at 60℃.This method enables live cell imaging of bacterial growth under anaerobic and thermophilic conditions and should be widely applicable to visualizing different cell types or processes in real time.

  15. Comparison of microbial communities during the anaerobic digestion of Gracilaria under mesophilic and thermophilic conditions.

    Science.gov (United States)

    Azizi, Aqil; Kim, Wonduck; Lee, Jung Hyun

    2016-10-01

    Mesophilic and thermophilic anaerobic digesters (MD and TD, respectively) utilizing Gracilaria and marine sediment as the substrate and inoculum, respectively, were compared by analyzing their performances and microbial community changes. During three successive transfers, the average cumulative methane yields in the MD and TD were 222.6 ± 17.3 mL CH4/g volatile solids (VS) and 246.1 ± 11 mL CH4/g VS, respectively. The higher hydrolysis rate and acidogenesis in the TD resulted in a several fold greater accumulation of volatile fatty acids (acetate, propionate, and butyrate) followed by a larger pH drop with a prolonged recovery than in the MD. However, the operational stability between both digesters remained comparable. Pyrosequencing analyses revealed that the MD had more complex microbial diversity indices and microbial community changes than the TD. Interestingly, Methanomassiliicoccales, the seventh methanogen order was the predominant archaeal order in the MD along with bacterial orders of Clostridiales, Bacteriodales, and Synergistales. Meanwhile, Coprothermobacter and Methanobacteriales dominated the bacterial and archaeal community in the TD, respectively. Although the methane yield is comparable, both MD and TD show a different profile of pH, VFA and the microbial communities.

  16. 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.

  17. Mass and Energy Balances of Dry Thermophilic Anaerobic Digestion Treating Swine Manure Mixed with Rice Straw

    Directory of Open Access Journals (Sweden)

    Sheng Zhou

    2015-01-01

    Full Text Available To evaluate the feasibility of swine manure treatment by a proposed Dry Thermophilic Anaerobic Digestion (DT-AD system, we evaluated the methane yield of swine manure treated using a DT-AD method with rice straw under different C/N ratios and solid retention time (SRT and calculated the mass and energy balances when the DT-AD system is used for swine manure treatment from a model farm with 1000 pigs and the digested residue is used for forage rice production. A traditional swine manure treatment Oxidation Ditch system was used as the study control. The results suggest that methane yield using the proposed DT-AD system increased with a higher C/N ratio and shorter SRT. Correspondently, for the DT-AD system running with SRT of 80 days, the net energy yields for all treatments were negative, due to low biogas production and high heat loss of digestion tank. However, the biogas yield increased when the SRT was shortened to 40 days, and the generated energy was greater than consumed energy when C/N ratio was 20:1 and 30:1. The results suggest that with the correct optimization of C/N ratio and SRT, the proposed DT-AD system, followed by using digestate for forage rice production, can attain energy self-sufficiency.

  18. Biohydrogen production from arabinose and glucose using extreme thermophilic anaerobic mixed cultures

    DEFF Research Database (Denmark)

    De Abreu, Angela Alexandra Valente; Karakashev, Dimitar Borisov; Angelidaki, Irini;

    2012-01-01

    differences in reactor performance were observed for arabinose and glucose organic loading rates (OLR) ranging from 4.3 to 7.1 kgCOD m-3 d-1. However, for an OLR of 14.2 kgCOD m-3 d-1, hydrogen production rate and hydrogen yield were higher in Rarab than in Rgluc (average hydrogen production rate of 3.2 and 2......Background Second generation hydrogen fermentation technologies using organic agricultural and forestry wastes are emerging. The efficient microbial fermentation of hexoses and pentoses resulting from the pretreatment of lingocellulosic materials is essential for the success of these processes....... Results Conversion of arabinose and glucose to hydrogen, by extreme thermophilic anaerobic mixed cultures was studied in continuous (70oC, pH 5.5) and batch (70oC, pH 5.5 and pH 7) assays. Two EGSB reactors, Rarab and Rgluc, were continuously fed with arabinose and glucose, respectively. No significant...

  19. Mixing effect on thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste

    KAUST Repository

    Ghanimeh, Sophia A.

    2012-08-01

    This paper examines the effect of mixing on the performance of thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste during the start-up phase and in the absence of an acclimated seed. For this purpose, two digesters were used under similar starting conditions and operated for 235days with different mixing schemes. While both digesters exhibited a successful startup with comparable specific methane yield of 0.327 and 0.314l CH 4/gVS, continuous slow stirring improved stability by reducing average VFA accumulation from 2890 to 825mg HAc/l, propionate content from 2073 to 488mg/l, and VFA-to-alkalinity ratio from 0.32 to 0.07. As a result, the startup with slow mixing was faster and smoother accomplishing a higher loading capacity of 2.5gVS/l/d in comparison to 1.9gVS/l/d for non-mixing. Mixing equally improved microbial abundance from 6.6 to 10gVSS/l and enhanced solids and soluble COD removal. © 2012 Elsevier Ltd.

  20. A Novel Process Configuration for Anaerobic Digestion of Source-Sorted Household Waste Using Hyper-Thermophilic Post-Treatment

    DEFF Research Database (Denmark)

    Hartmann, H.; Ahring, Birgitte Kiær

    2005-01-01

    A novel reactor configuration was investigated for anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW). An anaerobic hyper-thermophilic (68°C) reactor R68 was implemented as a post–treatment step for the effluent of a thermophilic reactor R1 (55°C) in order to enhance...... hydrolysis of recalcitrant organic matter, improve sanitation and ease the stripping of ammonia from the reactor. The efficiency of the combined system was studied in terms of methane yield, volatile solids (VS) reduction and volatile fatty acid (VFA) production at different hydraulic retention times (HRT......). A single-stage thermophilic (55°C) reactor R2 was used as control. VS reduction and biogas yield of the combined system was 78 – 89% and 640 – 790 ml/g-VS, respectively. While the VS reduction in the combined system was up to 7% higher than in the single-stage treatment, no increase in methane yield...

  1. Mesophilic and thermophilic anaerobic digestion of the liquid fraction of pressed biowaste for high energy yields recovery.

    Science.gov (United States)

    Micolucci, Federico; Gottardo, Marco; Cavinato, Cristina; Pavan, Paolo; Bolzonella, David

    2016-02-01

    Deep separate collection of the organic fraction of municipal solid waste generates streams with relatively low content of inert material and high biodegradability. This material can be conveniently treated to recovery both energy and material by means of simplified technologies like screw-press and extruder: in this study, the liquid fraction generated from pressed biowaste from kerbside and door-to-door collection was anaerobically digested in both mesophilic and thermophilic conditions while for the solid fraction composting is suggested. Continuous operation results obtained both in mesophilic and thermophilic conditions indicated that the anaerobic digestion of pressed biowaste was viable at all operating conditions tested, with the greatest specific gas production of 0.92m(3)/kgVSfed at an organic loading rate of 4.7kgVS/m(3)d in thermophilic conditions. Based on calculations the authors found that the expected energy recovery is highly positive. The contents of heavy metals and pathogens of fed substrate and effluent digestates were analyzed, and results showed low levels (below End-of-Waste 2014 criteria limits) for both the parameters thus indicating the good quality of digestate and its possible use for agronomic purposes. Therefore, both energy and material were effectively recovered. PMID:26427935

  2. Microbial ecology of thermophilic anaerobic digestion. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Stephen H. Zinder

    2000-04-15

    This grant supported research on methanogenic archaea. The two major areas that were supported were conversion of acetic acid to methane and nitrogen fixation by Methanosarcina. Among the achievements of this research were the isolation of novel methanogenic cultures, elucidation of the pathways from acetate to methane, description of a specific DNA-binding complex in nitrogen fixing methanogens, and demonstration of an alternative nitrogenase in Methanosarcina.

  3. Thermophilic-anaerobic digestion to produce class A biosolids: initial full-scale studies at Hyperion Treatment Plant.

    Science.gov (United States)

    Iranpour, R; Cox, H H J; Oh, S; Fan, S; Kearney, R J; Abkian, V; Haug, R T

    2006-02-01

    The highest quality of biosolids is called exceptional quality. To qualify for this classification, biosolids must comply with three criteria: (1) metal concentrations, (2) vector-attraction reduction, and (3) the Class A pathogen-density requirements. The City of Los Angeles Bureau of Sanitation Hyperion Treatment Plant (HTP) (Playa del Rey, California) meets the first two requirements. Thus, the objective of this study was to ensure that HTP's biosolids production would meet the Class A pathogen-reduction requirements following the time-temperature regimen for batch processing (U.S. EPA, 1993; Subsection 32, Alternative 1). Because regulations require the pathogen limits to be met at the last point of plant control, biosolids sampling was not limited to immediately after the digesters, i.e., the digester outflows. The sampling extended to several locations in HTP's postdigestion train, in particular, the last points of plant control, i.e., the truck loading facility and the farm for land application. A two-stage, thermophilic-continuous-batch process, consisting of a battery of six egg-shaped digesters, was established in late 2001 for phase I of this study and modified in early 2002 for phase II. As the biosolids were discharged from the second-stage digesters, the Salmonella sp. (pathogen) and fecal-coliform (indicator) densities were well below the limits for Class A biosolids, even though the second-stage-digester temperatures were a few degrees below the temperature required by Alternative 1. Salmonella sp. densities remained below the Class A limit at all postdigestion sampling locations. Fecal-coliform densities were also below the Class A limit at postdigestion-sampling locations, except the truck-loading facility (phases I and II) and the farm for final use of the biosolids (phase II). Although federal regulations require one of the limits for either fecal coliforms or Salmonella sp. to be met, local regulations in Kern County, California, where the

  4. Biohydrogen production by anaerobic fermentation of waste. Final project report

    Energy Technology Data Exchange (ETDEWEB)

    Karakashev, D.; Angelidaki, I.

    2009-01-15

    The objective of this project was to investigate and increase dark fermentative hydrogen production from organic wastes by optimizing important process parameters (reactor type, pH, temperature, organic loading, retention time, inoculation strategy, microbial composition). Labscale experiments were carried out at the Department of Environmental Engineering, Technical University of Denmark. A two steps process for hydrogen production in the first step and methane production in the second step in serial connected fully mixed reactors was developed and could successfully convert organic matter to approx. 20-25 % hydrogen and 15-80 % to methane. Sparging with methane produced in the second stage could significantly increase the hydrogen production. Additionally it was shown that upflow anaerobic sludge blanket (UASB) reactor system was very promising for high effective biohydrogen production from glucose at 70 deg C. Glucose-fed biofilm reactors filled with plastic carriers demonstrated high efficient extreme thermophilic biohydrogen production with mixed cultures. Repeated batch cultivations via exposure of the cultures to increased concentrations of household solid waste was found to be most useful method to enhance hydrogen production rate and reduce lag phase of extreme thermophilic fermentation process. Low level of pH (5.5) at 3-day HRT was enough to inhibit completely the methanogenesis and resulted in stable extreme thermophilic hydrogen production. Homoacetogenisis was proven to be an alternative competitor to biohydrogen production from organic acids under thermophilic (55 deg. C) conditions. With respect to microbiology, 16S rRNA targeted oligonucleotide probes were designed to monitor the spatial distribution of hydrogen producing bacteria in sludge and granules from anaerobic reactors. An extreme thermophilic (70 deg. C), strict anaerobic, mixed microbial culture with high hydrogen producing potential was enriched from digested household waste. Culture

  5. 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

    subsequent thermophilic digestion of primary sludge. The methane production rate was mostly influenced by the pre-treatment of secondary sludge followed by mesophilic and thermophilic digestion whereas the methane potential only was positively influenced when mesophilic digestion followed. Our results...... 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...... suggest that the selection of the pre-treatment duration as well as the temperature of the subsequent anaerobic step for sludge stabilization should depend on the ratio of primary to secondary sludge....

  6. Improving the stability of thermophilic anaerobic digesters treating SS-OFMSW through enrichment with compost and leachate seeds

    KAUST Repository

    Ghanimeh, Sophia A.

    2013-03-01

    This paper examines the potential of improving the stability of thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste (SS-OFMSW) by adding leachate and compost during inoculation. For this purpose, two stable thermophilic digesters, A (control) and B (with added leachate and compost), were subjected to a sustained substrate shock by doubling the organic loading rate for one week. Feeding was suspended then gradually resumed to reach the pre-shock loading rate (2. gVS/l/d). Digester A failed, exhibiting excessive increase in acetate and a corresponding decrease in pH and methane generation, and lower COD and solids removal efficiencies. In contrast, digester B was able to restore its functionality with 90% recovery of pre-shock methane generation rate at stable pH, lower hydrogen levels, and reduced VFAs and ammonia accumulation. © 2012 Elsevier Ltd.

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

    DEFF Research Database (Denmark)

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

    2002-01-01

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

  8. High rate mesophilic, thermophilic, and temperature phased anaerobic digestion of waste activated sludge: A pilot scale study

    International Nuclear Information System (INIS)

    Highlights: ► High temperatures were tested in single and two-stage anaerobic digestion of waste activated sludge. ► The increased temperature demonstrated the possibility of improving typical yields of the conventional mesophilic process. ► The temperature phased anaerobic digestion process (65 + 55 °C) showed the best performances with yields of 0.49 m3/kgVSfed. ► Ammonia and phosphate released from solids destruction determined the precipitation of struvite in the reactor. - Abstract: The paper reports the findings of a two-year pilot scale experimental trial for the mesophilic (35 °C), thermophilic (55 °C) and temperature phased (65 + 55 °C) anaerobic digestion of waste activated sludge. During the mesophilic and thermophilic runs, the reactor operated at an organic loading rate of 2.2 kgVS/m3d and a hydraulic retention time of 20 days. In the temperature phased run, the first reactor operated at an organic loading rate of 15 kgVS/m3d and a hydraulic retention time of 2 days while the second reactor operated at an organic loading rate of 2.2 kgVS/m3d and a hydraulic retention time of 18 days (20 days for the whole temperature phased system). The performance of the reactor improved with increases in temperature. The COD removal increased from 35% in mesophilic conditions, to 45% in thermophilic conditions, and 55% in the two stage temperature phased system. As a consequence, the specific biogas production increased from 0.33 to 0.45 and to 0.49 m3/kgVSfed at 35, 55, and 65 + 55 °C, respectively. The extreme thermophilic reactor working at 65 °C showed a high hydrolytic capability and a specific yield of 0.33 gCOD (soluble) per gVSfed. The effluent of the extreme thermophilic reactor showed an average concentration of soluble COD and volatile fatty acids of 20 and 9 g/l, respectively. Acetic and propionic acids were the main compounds found in the acids mixture. Because of the improved digestion efficiency, organic nitrogen and phosphorus were

  9. Probing the redox metabolism in the strictly anaerobic, extremely thermophilic, hydrogen-producing Caldicellulosiruptor saccharolyticus using amperometry

    DEFF Research Database (Denmark)

    Kostesha, Natalie; Willquist, Karin; Emnéus, Jenny;

    2011-01-01

    flow between cells harvested in the exponential and stationary growth phases. The electron flow of C. saccharolyticus was dependent on the NADH- and reduced ferredoxin generation flux and the competitive behavior of cytosolic and membrane-associated oxidoreductases. Sodium oxamate was used to inhibit...... electron flow were observed when cells were supplied with different carbon sources. A higher electrochemical response was detected when cells were supplied with xylose than with sucrose or glucose. Moreover, using the mediated electrochemical method, it was possible to detect differences in the electron...... in the intracellular electron flow and to probe redox enzyme properties of a strictly anaerobic thermophile in vivo....

  10. Anaerobic fermentation of beef cattle manure. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, A.G.; Chen, Y.R.; Varel, V.H.

    1981-01-01

    The research to convert livestock manure and crop residues into methane and a high protein feed ingredient by thermophilic anaerobic fermentation are summarized. The major biological and operational factors involved in methanogenesis were discussed, and a kinetic model that describes the fermentation process was presented. Substrate biodegradability, fermentation temperature, and influent substrate concentration were shown to have significant effects on CH/sub 4/ production rate. The kinetic model predicted methane production rates of existing pilot and full-scale fermentation systems to within 15%. The highest methane production rate achieved by the fermenter was 4.7 L CH/sub 4//L fermenter day. This is the highest rate reported in the literature and about 4 times higher than other pilot or full-scale systems fermenting livestock manures. Assessment of the energy requirements for anaerobic fermentation systems showed that the major energy requirement for a thermophilic system was for maintaining the fermenter temperature. The next major energy consumption was due to the mixing of the influent slurry and fermenter liquor. An approach to optimizing anaerobic fermenter designs by selecting design criteria that maximize the net energy production per unit cost was presented. Based on the results, we believe that the economics of anaerobic fermentation is sufficiently favorable for farm-scale demonstration of this technology.

  11. A comparison of microbial characteristics between the thermophilic and mesophilic anaerobic digesters exposed to elevated food waste loadings.

    Science.gov (United States)

    Guo, Xiaohui; Wang, Cheng; Sun, Faqian; Zhu, Weijing; Wu, Weixiang

    2014-01-01

    Thermophilic and mesophilic anaerobic digestion reactors (TR and MR) using food waste as substrate were compared with emphasis on microbial responses to increasing organic loading rate (OLR). At OLR ranging from 1.0 to 2.5 g VS L(-1) d(-1), MR exhibited more stable performance compared to TR in terms of methane yield. Amplicons pyrosequencing results revealed the distinct microbial dynamics in the two reactors. Primarily, MR had greater richness and evenness of bacteria species. With OLR elevated, larger shifts of bacterial phylogeny were observed in MR; Methanosaeta dominated in archaeal community in MR while Methanothermobacter and Methanoculleus were favored in TR. The high functional redundancy in bacterial community integrated with acetoclastic methanogenesis in MR resulted in its better performance; whereas delicate interactions between hydrogen-producer and hydrogenotrophic methanogens in TR were much more prone to disruption. These results are conductive to understanding the microbial mechanisms of low methane yield during food waste anaerobic digestion.

  12. Caloramator quimbayensis sp. nov., an anaerobic, moderately thermophilic bacterium isolated from a terrestrial hot spring.

    Science.gov (United States)

    Rubiano-Labrador, Carolina; Baena, Sandra; Díaz-Cárdenas, Carolina; Patel, Bharat K C

    2013-04-01

    An anaerobic, moderately thermophilic, terminal-spore-forming bacterium, designated strain USBA A(T), was isolated from a terrestrial hot spring located at an altitude of 2683 m in the Andean region of Colombia (04° 50' 14.0″ N 75° 32' 53.4″ W). Cells of strain USBA A(T) were Gram-stain-positive, straight to slightly curved rods (0.9×2.5 µm), that were arranged singly or in pairs, and were motile by means of flagella. Growth occurred at 37-55 °C and pH 6.0-8.0, with a doubling time of 2 h under the optimal conditions (50 °C and pH 7.0). Glucose fermentation in strain USBA A(T) required yeast extract or peptone (each at 0.2 %, w/v). The novel strain fermented sugars, amino acids, Casamino acids, propanol, propionate, starch and dextrin, but no growth was observed on galactose, lactose, xylose, histidine, serine, threonine, benzoate, butyrate, lactate, pyruvate, succinate, methanol, ethanol, glycerol, casein, gelatin or xylan. The end products of glucose fermentation were formate, acetate, ethanol and lactate. Strain USBA A(T) did not grow autotrophically (with CO2 as carbon source and H2 as electron donor) and did not reduce thiosulfate, sulfate, elemental sulfur, sulfite, vanadium (V) or Fe (III) citrate. Growth of strain USBA A(T) was inhibited by ampicillin, chloramphenicol, kanamycin, penicillin and streptomycin (each at 10 µg ml(-1)). The predominant fatty acids were iso-C15 : 0, C16 : 0 and iso-C17 : 0 and the genomic DNA G+C content was 32.6 mol%. 16S rRNA gene sequence analysis indicated that strain USBA A(T) belonged in the phylum Firmicutes and that its closest relative was Caloramator viterbiensis JW/MS-VS5(T) (95.0 % sequence similarity). A DNA-DNA relatedness value of only 30 % was recorded in hybridization experiments between strain USBA A(T) and Caloramator viterbiensis DSM 13723(T). Based on the phenotypic, chemotaxonomic and phylogenetic evidence and the results of the DNA-DNA hybridization experiments, strain USBA A

  13. Fervidicella metallireducens gen. nov., sp. nov., a thermophilic, anaerobic bacterium from geothermal waters.

    Science.gov (United States)

    Ogg, Christopher D; Patel, Bharat K C

    2010-06-01

    A strictly anaerobic, thermophilic bacterium, designated strain AeB(T), was isolated from microbial mats colonizing a run-off channel formed by free-flowing thermal water from a bore well (registered number 17263) of the Great Artesian Basin, Australia. Cells of strain AeB(T) were slightly curved rods (2.5-6.0x1.0 mum) that stained Gram-negative and formed spherical terminal to subterminal spores. The strain grew optimally in tryptone-yeast extract-Casamino acids medium at 50 degrees C (range 37-55 degrees C) and pH 7 (range pH 5-9). Strain AeB(T) grew poorly on yeast extract (0.2 %) and tryptone (0.2 %) as sole carbon sources, which were obligately required for growth on other energy sources. Growth of strain AeB(T) increased in the presence of various carbohydrates and amino acids, but not organic acids. End products detected from glucose fermentation were ethanol, acetate, CO2 and H2. In the presence of 0.2 % yeast extract, iron(III), manganese(IV), vanadium(V) and cobalt(III) were reduced, but not sulfate, thiosulfate, sulfite, elemental sulfur, nitrate or nitrite. Iron(III) was also reduced in the presence of tryptone, peptone, Casamino acids and amyl media (Research Achievement), but not starch, xylan, chitin, glycerol, ethanol, pyruvate, benzoate, lactate, acetate, propionate, succinate, glycine, serine, lysine, threonine, arginine, glutamate, valine, leucine, histidine, alanine, aspartate, isoleucine or methionine. Growth was inhibited by chloramphenicol, streptomycin, tetracycline, penicillin, ampicillin and NaCl concentrations >2 %. The DNA G+C content was 35.4+/-1 mol%, as determined by the thermal denaturation method. 16S rRNA gene sequence analysis indicated that strain AeB(T) is a member of the family Clostridiaceae, class Clostridia, phylum 'Firmicutes', and is positioned approximately equidistantly between the genera Sarcina, Anaerobacter, Caloramator and Clostridium (16S rRNA gene similarity values of 87.8-90.9 %). On the basis of 16S rRNA gene

  14. Caloramator quimbayensis sp. nov., an anaerobic, moderately thermophilic bacterium isolated from a terrestrial hot spring.

    Science.gov (United States)

    Rubiano-Labrador, Carolina; Baena, Sandra; Díaz-Cárdenas, Carolina; Patel, Bharat K C

    2013-04-01

    An anaerobic, moderately thermophilic, terminal-spore-forming bacterium, designated strain USBA A(T), was isolated from a terrestrial hot spring located at an altitude of 2683 m in the Andean region of Colombia (04° 50' 14.0″ N 75° 32' 53.4″ W). Cells of strain USBA A(T) were Gram-stain-positive, straight to slightly curved rods (0.9×2.5 µm), that were arranged singly or in pairs, and were motile by means of flagella. Growth occurred at 37-55 °C and pH 6.0-8.0, with a doubling time of 2 h under the optimal conditions (50 °C and pH 7.0). Glucose fermentation in strain USBA A(T) required yeast extract or peptone (each at 0.2 %, w/v). The novel strain fermented sugars, amino acids, Casamino acids, propanol, propionate, starch and dextrin, but no growth was observed on galactose, lactose, xylose, histidine, serine, threonine, benzoate, butyrate, lactate, pyruvate, succinate, methanol, ethanol, glycerol, casein, gelatin or xylan. The end products of glucose fermentation were formate, acetate, ethanol and lactate. Strain USBA A(T) did not grow autotrophically (with CO2 as carbon source and H2 as electron donor) and did not reduce thiosulfate, sulfate, elemental sulfur, sulfite, vanadium (V) or Fe (III) citrate. Growth of strain USBA A(T) was inhibited by ampicillin, chloramphenicol, kanamycin, penicillin and streptomycin (each at 10 µg ml(-1)). The predominant fatty acids were iso-C15 : 0, C16 : 0 and iso-C17 : 0 and the genomic DNA G+C content was 32.6 mol%. 16S rRNA gene sequence analysis indicated that strain USBA A(T) belonged in the phylum Firmicutes and that its closest relative was Caloramator viterbiensis JW/MS-VS5(T) (95.0 % sequence similarity). A DNA-DNA relatedness value of only 30 % was recorded in hybridization experiments between strain USBA A(T) and Caloramator viterbiensis DSM 13723(T). Based on the phenotypic, chemotaxonomic and phylogenetic evidence and the results of the DNA-DNA hybridization experiments, strain USBA A

  15. Biohydrogen production from arabinose and glucose using extreme thermophilic anaerobic mixed cultures

    Directory of Open Access Journals (Sweden)

    Abreu Angela A

    2012-02-01

    Full Text Available Abstract Background Second generation hydrogen fermentation technologies using organic agricultural and forestry wastes are emerging. The efficient microbial fermentation of hexoses and pentoses resulting from the pretreatment of lingocellulosic materials is essential for the success of these processes. Results Conversion of arabinose and glucose to hydrogen, by extreme thermophilic, anaerobic, mixed cultures was studied in continuous (70°C, pH 5.5 and batch (70°C, pH 5.5 and pH 7 assays. Two expanded granular sludge bed (EGSB reactors, Rarab and Rgluc, were continuously fed with arabinose and glucose, respectively. No significant differences in reactor performance were observed for arabinose and glucose organic loading rates (OLR ranging from 4.3 to 7.1 kgCOD m-3 d-1. However, for an OLR of 14.2 kgCOD m-3 d-1, hydrogen production rate and hydrogen yield were higher in Rarab than in Rgluc (average hydrogen production rate of 3.2 and 2.0 LH2 L-1 d-1 and hydrogen yield of 1.10 and 0.75 molH2 mol-1substrate for Rarab and Rgluc, respectively. Lower hydrogen production in Rgluc was associated with higher lactate production. Denaturing gradient gel electrophoresis (DGGE results revealed no significant difference on the bacterial community composition between operational periods and between the reactors. Increased hydrogen production was observed in batch experiments when hydrogen partial pressure was kept low, both with arabinose and glucose as substrate. Sugars were completely consumed and hydrogen production stimulated (62% higher when pH 7 was used instead of pH 5.5. Conclusions Continuous hydrogen production rate from arabinose was significantly higher than from glucose, when higher organic loading rate was used. The effect of hydrogen partial pressure on hydrogen production from glucose in batch mode was related to the extent of sugar utilization and not to the efficiency of substrate conversion to hydrogen. Furthermore, at pH 7.0, sugars

  16. Thermophillic treatment by anaerobic granular sludge as an effective approach to accelerate the electron transfer and improve the reductive decolorization of azo dyes in bioreactors

    NARCIS (Netherlands)

    Santos, dos A.B.; Traverse, J.; Cervantes, F.J.; Lier, van J.B.

    2005-01-01

    The effects of temperature, hydraulic retention time (HRT), and the redox mediator, thraquinone- 2,6-disulfonate (AQDS), on electron transfer and subsequent reductive decolorization of dyes rom textile wastewater was assessed in mesophilic and thermophilic anaerobic bioreactors. The results clearly

  17. Effect of redox mediator, AQDS, on the decolourisation of a reactive azo dye containing triazine group in a thermophilic anaerobic EGSB reactor

    NARCIS (Netherlands)

    Bezerra Dos Santos, A.; Cervantes-Carillo, F.J.; Yaya Beas, R.E.; Lier, van J.B.

    2003-01-01

    The feasibility of thermophilic (55 degreesC) anaerobic treatment applied to colour removal of a triazine contained reactive azo dye was investigated in two 0.531 expanded granular sludge blanket (EGSB) reactors in parallel at a hydraulic retention time (HRT) of 10 h. Generally, this group of azo dy

  18. Performance and kinetic study of semi-dry thermophilic anaerobic digestion of organic fraction of municipal solid waste

    Energy Technology Data Exchange (ETDEWEB)

    Sajeena Beevi, B., E-mail: sajeenanazer@gmail.com [Department of Chemical Engineering, Govt. Engineering College, Thrissur, Kerala 680 009 (India); Madhu, G., E-mail: profmadhugopal@gmail.com [Division of Safety & Fire Engineering, School of Engineering, Cochin University of Science and Technology, Cochin, Kerala 682 022 (India); Sahoo, Deepak Kumar, E-mail: dksahoo@gmail.com [Division of Safety & Fire Engineering, School of Engineering, Cochin University of Science and Technology, Cochin, Kerala 682 022 (India)

    2015-02-15

    Highlights: • Performance of the reactor was evaluated by the degradation of volatile solids. • Biogas yield at the end of the digestion was 52.9 L/kg VS. • Value of reaction rate constant, k, obtained was 0.0249 day{sup −1}. • During the digestion 66.7% of the volatile solid degradation was obtained. - Abstract: Anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW) is promoted as an energy source and waste disposal. In this study semi dry anaerobic digestion of organic solid wastes was conducted for 45 days in a lab-scale batch experiment for total solid concentration of 100 g/L for investigating the start-up performances under thermophilic condition (50 °C). The performance of the reactor was evaluated by measuring the daily biogas production and calculating the degradation of total solids and the total volatile solids. The biogas yield at the end of the digestion was 52.9 L/kg VS (volatile solid) for the total solid (TS) concentration of 100 g/L. About 66.7% of the volatile solid degradation was obtained during the digestion. A first order model based on the availability of substrate as the limiting factor was used to perform the kinetic studies of batch anaerobic digestion system. The value of reaction rate constant, k, obtained was 0.0249 day{sup −1}.

  19. Candidatus Desulfofervidus auxilii, a hydrogenotrophic sulfate-reducing bacterium involved in the thermophilic anaerobic oxidation of methane.

    Science.gov (United States)

    Krukenberg, Viola; Harding, Katie; Richter, Michael; Glöckner, Frank Oliver; Gruber-Vodicka, Harald R; Adam, Birgit; Berg, Jasmine S; Knittel, Katrin; Tegetmeyer, Halina E; Boetius, Antje; Wegener, Gunter

    2016-09-01

    The anaerobic oxidation of methane (AOM) is mediated by consortia of anaerobic methane-oxidizing archaea (ANME) and their specific partner bacteria. In thermophilic AOM consortia enriched from Guaymas Basin, members of the ANME-1 clade are associated with bacteria of the HotSeep-1 cluster, which likely perform direct electron exchange via nanowires. The partner bacterium was enriched with hydrogen as sole electron donor and sulfate as electron acceptor. Based on phylogenetic, genomic and metabolic characteristics we propose to name this chemolithoautotrophic sulfate reducer Candidatus Desulfofervidus auxilii. Ca. D. auxilii grows on hydrogen at temperatures between 50°C and 70°C with an activity optimum at 60°C and doubling time of 4-6 days. Its genome draft encodes for canonical sulfate reduction, periplasmic and soluble hydrogenases and autotrophic carbon fixation via the reductive tricarboxylic acid cycle. The presence of genes for pili formation and cytochromes, and their similarity to genes of Geobacter spp., indicate a potential for syntrophic growth via direct interspecies electron transfer when the organism grows in consortia with ANME. This first ANME-free enrichment of an AOM partner bacterium and its characterization opens the perspective for a deeper understanding of syntrophy in anaerobic methane oxidation. PMID:26971539

  20. 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.

  1. A comparative study on the alternating mesophilic and thermophilic two-stage anaerobic digestion of food waste.

    Science.gov (United States)

    Ventura, Jey-R Sabado; Lee, Jehoon; Jahng, Deokjin

    2014-06-01

    An alternating mesophilic and thermophilic two stage anaerobic digestion (AD) process was conducted. The temperature of the acidogenic (A) and methanogenic (M) reactors was controlled as follows: System 1 (S1) mesophilic A-mesophilic M; (S2) mesophilic A-thermophilic M; and (S3) thermophilic A-mesophilic M. Initially, the AD reactor was acclimatized and inoculated with digester sludge. Food waste was added with the soluble chemical oxygen demand (SCOD) concentrations of 41.4-47.0 g/L and volatile fatty acids of 2.0-3.2 g/L. Based on the results, the highest total chemical oxygen demand removal (86.6%) was recorded in S2 while S3 exhibited the highest SCOD removal (96.6%). Comparing S1 with S2, total solids removal increased by 0.5%; S3 on the other hand decreased by 0.1 % as compared to S1. However, volatile solids (VS) removal in S1, S2, and S3 was 78.5%, 81.7%, and 79.2%, respectively. S2 also exhibited the highest CH4 content, yield, and production rate of 70.7%, 0.44 L CH4/g VSadded, and 1.23 L CH4/(L·day), respectively. Bacterial community structure revealed that the richness, diversity, evenness, and dominance of S2 were high except for the archaeal community. The terminal restriction fragments dendrogram also revealed that the microbial community of the acidogenic and methanogenic reactors in S2 was distinct. Therefore, S2 was the best among the systems for the operation of two-stage AD of food waste in terms of CH4 production, nutrient removal, and microbial community structure. PMID:25079836

  2. Thermophilic anaerobes in arctic marine sediments induced to mineralize complex organic matter at high temperature

    DEFF Research Database (Denmark)

    Hubert, Casey; Arnosti, Carol; Brüchert, Volker;

    2010-01-01

    Marine sediments harbour diverse populations of dormant thermophilic bacterial spores that become active in sediment incubation experiments at much higher than in situ temperature. This response was investigated in the presence of natural complex organic matter in sediments of two Arctic fjords, ...

  3. Pretreatment of wheat straw and conversion of xylose and xylan to ethanol by thermophilic anaerobic bacteria

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær; Jensen, K.; Nielsen, P.;

    1996-01-01

    . Of five different thermophilic bacteria used in this study only two strains produced ethanol with xylan as substrate, one of them being the strain A3 isolated from an Icelandic hot-spring. Probably other degradation products formed in the presence of oxygen might act as inhibitors. Adaptation...

  4. 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. PMID:27295255

  5. Increased temperature in the thermophilic stage in temperature phased anaerobic digestion (TPAD) improves degradability of waste activated sludge.

    Science.gov (United States)

    Ge, Huoqing; Jensen, Paul D; Batstone, Damien J

    2011-03-15

    Two-stage temperature phased anaerobic digestion (TPAD) is an increasingly popular method to improve stabilisation of sewage waste activated sludge, which normally has inherently poor and slow degradation. However, there has been limited systematic analysis of the impact of the initial thermophilic stage (temperature, pH and retention time) on performance in the main mesophilic stage. In this study, we demonstrate a novel two-stage batch test method for TPAD processes, and use it to optimize operating conditions of the thermophilic stage in terms of degradation extent and methane production. The method determines overall degradability and apparent hydrolysis coefficient in both stages. The overall process was more effective with short pre-treatment retention times (1-2 days) and neutral pH compared to longer retention time (4 days) and low pH (4-5). Degradabilities and apparent hydrolysis coefficients were 0.3-0.5 (fraction degradable) and 0.1-0.4d(-1), respectively, with a margin of error in each measurement of approximately 20% relative (95% confidence). Pre-treatment temperature had a strong impact on the whole process, increasing overall degradability from 0.3 to 0.5 as temperature increased from 50 to 65 °C, with apparent hydrolysis coefficient increasing from 0.1 to 0.4d(-1). PMID:21277081

  6. Thermostilla marina gen. nov., sp. nov., a thermophilic, facultatively anaerobic planctomycete isolated from a shallow submarine hydrothermal vent.

    Science.gov (United States)

    Slobodkina, Galina B; Panteleeva, Angela N; Beskorovaynaya, Darya A; Bonch-Osmolovskaya, Elizaveta A; Slobodkin, Alexander I

    2016-02-01

    A novel thermophilic planctomycete (strain SVX8T) was isolated from a shallow submarine hydrothermal vent, Vulcano Island, Italy. The temperature range for growth was 30-68 °C, with an optimum at 55 °C. The pH range for growth was 5.0-9.0, with an optimum at pH 7.0-8.0. Growth was observed at NaCl concentrations ranging from 0.8 to 4.5 % (w/v) with an optimum at 2.5-3.5 % (w/v). The isolate grew anaerobically using a number of mono-, di- and polysaccharides as electron donors and nitrate or elemental sulfur as electron acceptors or by fermentation. Nitrate was reduced to nitrite; sulfur was reduced to sulfide. Strain SVX8T did not grow at atmospheric concentration of oxygen but grew microaerobically (up to 2 % oxygen in the gas phase). The G+C content of the DNA of strain SVX8T was 58.5 mol%. Based on phylogenetic position and phenotypic features, the new isolate is considered to represent a novel species belonging to a new genus in the order Planctomycetales, for which the name Thermostilla marina gen. nov., sp. nov. is proposed. The type strain of Thermostilla marina is SVX8T ( = JCM 19992T = VKM B-2881T). Strain SVX8T is the first thermophilic planctomycete isolated from a marine environment. PMID:26559645

  7. Adaption of microbial community during the start-up stage of a thermophilic anaerobic digester treating food waste.

    Science.gov (United States)

    Wu, Bo; Wang, Xing; Deng, Ya-Yue; He, Xiao-Lan; Li, Zheng-Wei; Li, Qiang; Qin, Han; Chen, Jing-Tao; He, Ming-Xiong; Zhang, Min; Hu, Guo-Quan; Yin, Xiao-Bo

    2016-10-01

    A successful start-up enables acceleration of anaerobic digestion (AD) into steady state. The microbial community influences the AD performance during the start-up. To investigate how microbial communities changed during the start-up, microbial dynamics was analyzed via high-throughput sequencing in this study. The results confirmed that the AD was started up within 25 d. Thermophilic methanogens and bacterial members functioning in hydrolysis, acidogenesis, and syntrophic oxidation became predominant during the start-up stage, reflecting a quick adaption of microorganisms to operating conditions. Such predominance also indicated the great contribution of these members to the fast start-up of AD. Redundancy analysis confirmed that the bacterial abundance significantly correlated with AD conditions. The stable ratio of hydrogenotrophic methanogens to aceticlastic methanogens is also important to maintain the stability of the AD process. This work will be helpful to understand the contribution of microbial community to the start-up of AD. PMID:27251412

  8. Operational strategies for thermophilic anaerobic digestion of organic fraction of municipal solid waste in continuously stirred tank reactors

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Cui, J.; Chen, X.;

    2006-01-01

    Three operational strategies to reduce inhibition due to ammonia during thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste (SS-OFMSW) rich in proteins were investigated. Feed was prepared by diluting SS-OFMSW (ratio of 1:4) with tap water or reactor process...... water with or without stripping ammonia. Three continuously stirred tank reactors were operated at 55 degrees C with 11.4 gVS d(-1) loading rate and 15 d retention time. Total ammonia nitrogen (TAN) level in the reactor fed with recirculated water alone was spiked to 3.5 and 5.5 g-N l(-1) through...... ammonium bicarbonate additions. Dilution of SS-OFMSW with fresh water showed a stable performance with volatile fatty acids of water after stripping ammonia showed even better performance with a methane yield...

  9. Ammonia inhibition on hydrogen enriched anaerobic digestion of manure under mesophilic and thermophilic conditions

    DEFF Research Database (Denmark)

    Wang, Han; Zhang, Yifeng; Angelidaki, Irini

    2016-01-01

    Capturing of carbon dioxide by hydrogen derived from excess renewable energy (e.g., wind mills) to methane in a microbially catalyzed process offers an attractive technology for biogas production and upgrading. This bioconversion process is catalyzed by hydrogenotrophic methanogens, which are known...... to be sensitive to ammonia. In this study, the tolerance of the biogas process under supply of hydrogen, to ammonia toxicity was studied under mesophilic and thermophilic conditions. When the initial hydrogen partial pressure was 0.5 atm, the methane yield at high ammonia load (7 g NH4+-N L−1) was 41.0% and 22...... methanogens in the hydrogen enriched biogas production and upgrading processes. The highest methane production yield was achieved under 0.5 atm hydrogen partial pressure in batch reactors at all the tested ammonia levels. Furthermore, the thermophilic methanogens at 0.5 atm of hydrogen partial pressure were...

  10. Comparing mesophilic and thermophilic anaerobic digestion of chicken manure: Microbial community dynamics and process resilience

    Energy Technology Data Exchange (ETDEWEB)

    Niu, Qigui; Takemura, Yasuyuki; Kubota, Kengo [Department of Civil and Environmental Engineering, Graduate School of Engineering Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Li, Yu-You, E-mail: yyli@epl1.civil.tohoku.ac.jp [Department of Civil and Environmental Engineering, Graduate School of Engineering Tohoku University, 6-6-06 Aza-Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Key Lab of Northwest Water Resource, Environment and Ecology, MOE, Xi’an University of Architecture and Technology, Xi’an (China)

    2015-09-15

    Highlights: • Microbial community dynamics and process functional resilience were investigated. • The threshold of TAN in mesophilic reactor was higher than the thermophilic reactor. • The recoverable archaeal community dynamic sustained the process resilience. • Methanosarcina was more sensitive than Methanoculleus on ammonia inhibition. • TAN and FA effects the dynamic of hydrolytic and acidogenic bacteria obviously. - Abstract: While methane fermentation is considered as the most successful bioenergy treatment for chicken manure, the relationship between operational performance and the dynamic transition of archaeal and bacterial communities remains poorly understood. Two continuous stirred-tank reactors were investigated under thermophilic and mesophilic conditions feeding with 10%TS. The tolerance of thermophilic reactor on total ammonia nitrogen (TAN) was found to be 8000 mg/L with free ammonia (FA) 2000 mg/L compared to 16,000 mg/L (FA1500 mg/L) of mesophilic reactor. Biomethane production was 0.29 L/gV S{sub in} in the steady stage and decreased following TAN increase. After serious inhibition, the mesophilic reactor was recovered successfully by dilution and washing stratagem compared to the unrecoverable of thermophilic reactor. The relationship between the microbial community structure, the bioreactor performance and inhibitors such as TAN, FA, and volatile fatty acid was evaluated by canonical correspondence analysis. The performance of methanogenic activity and substrate removal efficiency were changed significantly correlating with the community evenness and phylogenetic structure. The resilient archaeal community was found even after serious inhibition in both reactors. Obvious dynamics of bacterial communities were observed in acidogenic and hydrolytic functional bacteria following TAN variation in the different stages.

  11. Optimization of key factors affecting hydrogen production from sugarcane bagasse by a thermophilic anaerobic pure culture

    OpenAIRE

    Lai, Zhicheng; Zhu, Muzi; Yang, Xiaofeng; Wang, JuFang; Li, Shuang

    2014-01-01

    Background Hydrogen is regarded as an attractive future energy carrier for its high energy content and zero CO2 emission. Currently, the majority of hydrogen is generated from fossil fuels. However, from an environmental perspective, sustainable hydrogen production from low-cost lignocellulosic biomass should be considered. Thermophilic hydrogen production is attractive, since it can potentially convert a variety of biomass-based substrates into hydrogen at high yields. Results Sugarcane baga...

  12. Comparing mesophilic and thermophilic anaerobic digestion of chicken manure: Microbial community dynamics and process resilience

    International Nuclear Information System (INIS)

    Highlights: • Microbial community dynamics and process functional resilience were investigated. • The threshold of TAN in mesophilic reactor was higher than the thermophilic reactor. • The recoverable archaeal community dynamic sustained the process resilience. • Methanosarcina was more sensitive than Methanoculleus on ammonia inhibition. • TAN and FA effects the dynamic of hydrolytic and acidogenic bacteria obviously. - Abstract: While methane fermentation is considered as the most successful bioenergy treatment for chicken manure, the relationship between operational performance and the dynamic transition of archaeal and bacterial communities remains poorly understood. Two continuous stirred-tank reactors were investigated under thermophilic and mesophilic conditions feeding with 10%TS. The tolerance of thermophilic reactor on total ammonia nitrogen (TAN) was found to be 8000 mg/L with free ammonia (FA) 2000 mg/L compared to 16,000 mg/L (FA1500 mg/L) of mesophilic reactor. Biomethane production was 0.29 L/gV Sin in the steady stage and decreased following TAN increase. After serious inhibition, the mesophilic reactor was recovered successfully by dilution and washing stratagem compared to the unrecoverable of thermophilic reactor. The relationship between the microbial community structure, the bioreactor performance and inhibitors such as TAN, FA, and volatile fatty acid was evaluated by canonical correspondence analysis. The performance of methanogenic activity and substrate removal efficiency were changed significantly correlating with the community evenness and phylogenetic structure. The resilient archaeal community was found even after serious inhibition in both reactors. Obvious dynamics of bacterial communities were observed in acidogenic and hydrolytic functional bacteria following TAN variation in the different stages

  13. Comparing mesophilic and thermophilic anaerobic digestion of chicken manure: Microbial community dynamics and process resilience.

    Science.gov (United States)

    Niu, Qigui; Takemura, Yasuyuki; Kubota, Kengo; Li, Yu-You

    2015-09-01

    While methane fermentation is considered as the most successful bioenergy treatment for chicken manure, the relationship between operational performance and the dynamic transition of archaeal and bacterial communities remains poorly understood. Two continuous stirred-tank reactors were investigated under thermophilic and mesophilic conditions feeding with 10%TS. The tolerance of thermophilic reactor on total ammonia nitrogen (TAN) was found to be 8000mg/L with free ammonia (FA) 2000mg/L compared to 16,000mg/L (FA1500mg/L) of mesophilic reactor. Biomethane production was 0.29 L/gVSin in the steady stage and decreased following TAN increase. After serious inhibition, the mesophilic reactor was recovered successfully by dilution and washing stratagem compared to the unrecoverable of thermophilic reactor. The relationship between the microbial community structure, the bioreactor performance and inhibitors such as TAN, FA, and volatile fatty acid was evaluated by canonical correspondence analysis. The performance of methanogenic activity and substrate removal efficiency were changed significantly correlating with the community evenness and phylogenetic structure. The resilient archaeal community was found even after serious inhibition in both reactors. Obvious dynamics of bacterial communities were observed in acidogenic and hydrolytic functional bacteria following TAN variation in the different stages. PMID:26054964

  14. Bio-hydrogen and bio-methane potentials of skim latex serum in batch thermophilic two-stage anaerobic digestion.

    Science.gov (United States)

    Jariyaboon, Rattana; O-Thong, Sompong; Kongjan, Prawit

    2015-12-01

    Anaerobic digestion by two-stage process, containing hydrogen-producing (acidogenic) first stage and methanogenic second stage, has been proposed to degrade substrates which are difficult to be treated by single stage anaerobic digestion process. This research was aimed to evaluate the bio-hydrogen and the bio-methane potentials (BHP and BMP) of skim latex serum (SLS) by using sequential batch hydrogen and methane cultivations at thermophilic conditions (55°C) and with initial SLS concentrations of 37.5-75.0% (v/v). The maximal 1.57 L H2/L SLS for BHP and 12.2L CH4/L SLS for BMP were both achieved with 60% (v/v) SLS. The dominant hydrogen-producing bacteria in the H2 batch reactor were Thermoanaerobacterium sp. and Clostrdium sp. Meanwhile, the CH4 batch reactor was dominated by the methanogens Methanosarcina mazei and Methanothermobacter defluvii. The results demonstrate that SLS can be degraded by conversion to form hydrogen and methane, waste treatment and bioenergy production are thus combined. PMID:26386423

  15. Population dynamics during startup of thermophilic anaerobic digesters: The mixing factor

    KAUST Repository

    Ghanimeh, Sophia A.

    2013-11-01

    Two thermophilic digesters were inoculated with manure and started-up under mixed and stagnant conditions. The Archaea in the mixed digester (A) were dominated by hydrogenotrophic Methanobateriaceae (61%) with most of the methane being produced via syntrophic pathways. Methanosarcinales (35%) were the only acetoclastic methanogens present. Acetate dissipation seems to depend on balanced hydrogenotrophic-to-acetotrophic abundance, which in turn was statistically correlated to free ammonia levels. Relative abundance of bacterial community was associated with the loading rate. However, in the absence of mixing (digester B), the relationship between microbial composition and operating parameters was not discernible. This was attributed to the development of microenvironments where environmental conditions are significantly different from average measured parameters. The impact of microenvironments was accentuated by the use of a non-acclimated seed that lacks adequate propionate degraders. Failure to disperse the accumulated propionate, and other organics, created high concentration niches where competitive and inhibiting conditions developed and favored undesired genera, such as Halobacteria (65% in B). As a result, digester B experienced higher acid levels and lower allowable loading rate. Mixing was found necessary to dissipate potential inhibitors, and improve stability and loading capacity, particularly when a non-acclimated seed, often lacking balanced thermophilic microflora, is used. © 2013 Elsevier Ltd.

  16. Potential for using thermophilic anaerobic bacteria for bioethanol production from hemicellulose

    DEFF Research Database (Denmark)

    Sommer, P.; Georgieva, Tania I.; Ahring, Birgitte Kiær

    2004-01-01

    anaerobic bacterial strains growing optimally at 70-80degreesC for their ethanol production from D-Xylose. The new isolates came from different natural and man-made systems such as hot springs, paper pulp mills and brewery waste water. The test was composed of three different steps; (i) test for conversion...

  17. 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 fl

  18. The use of ultrasound and {gamma}-irradiation as pre-treatments for the anaerobic digestion of waste activated sludge at mesophilic and thermophilic temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Lafitte-Trouque, S.; Forster, C.F. [The University of Birmingham (United Kingdom). School of Engineering

    2002-09-01

    The effect of ultrasound and {gamma}-irradiation used as pre-treatments for the anaerobic digestion of waste activated sludge at both mesophilic and thermophilic temperatures was examined. Untreated activated sludge was also subjected to anaerobic digestion at these temperatures as a control. The sonication time was 90 s using a Soniprep 150 (MSE Scientific Instruments) which operated at 23 kHz and had been adjusted to give an output of 47 W and the {gamma}-irradiation dose was 500 krad. The digesters were operated in a semi-continuous mode, being fed with fresh sludge every 24 h at hydraulic retention times (HRT) of 8, 10 and 12 days. Over the 24 h period the differences between the digesters, in terms of volatile solids (VS) reductions and biogas production, were not statistically significant for any particular set of conditions. Thermophilic digestion performed better than mesophilic digestion in terms of biogas production, VS reductions (except at HRT of 8 days) and specific methane yields and the optimum retention time was 10 days, at both temperatures. When gas production over the initial eight hours (probably the hydrolytic stage) was examined, it was found that the gas production rates for pre-treated sludges were higher than those for untreated sludges. This was most pronounced at thermophilic temperatures and a HRT of 10 days. Sonication did not affect the numbers of faecal coliforms in the sludge. However, {gamma}-irradiation caused a 3-log reduction and, when coupled with mesophilic digestion, gave a product which contained <100 g{sup -1} TS. Thermophilic anaerobic digestion produced sludges which contained <1 g{sup -1} TS irrespective of any pre-treatment. (author)

  19. Characterization of cellulolytic enzymes and bioH2 production from anaerobic thermophilic Clostridium sp. TCW1.

    Science.gov (United States)

    Lo, Yung-Chung; Huang, Chi-Yu; Cheng, Chieh-Lun; Lin, Chiu-Yue; Chang, Jo-Shu

    2011-09-01

    A thermophilic anaerobic bacterium Clostridium sp. TCW1 was isolated from dairy cow dung and was used to produce hydrogen from cellulosic feedstock. Extracellular cellulolytic enzymes produced from TCW1 strain were identified as endoglucanases (45, 53 and 70 kDa), exoglucanase (70 kDa), xylanases (53 and 60 kDa), and β-glucosidase (45 kDa). The endoglucanase and xylanase were more abundant. The optimal conditions for H2 production and enzyme production of the TCW1 strain were the same (60 °C, initial pH 7, agitation rate of 200 rpm). Ten cellulosic feedstock, including pure or natural cellulosic materials, were used as feedstock for hydrogen production by Clostridium strain TCW1 under optimal culture conditions. Using filter paper at 5.0 g/L resulted in the most effective hydrogen production performance, achieving a H2 production rate and yield of 57.7 ml/h/L and 2.03 mol H2/mol hexose, respectively. Production of cellulolytic enzyme activities was positively correlated with the efficiency of dark-H2 fermentation.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-01-01

    A novel, obligately anaerobic, extremely thermophilic, cellulolytic bacterium, designated OB47T, was isolated from Obsidian Pool, Yellowstone National Park, WY, USA. The isolate was a non-motile, non-spore forming, Gram-positive rod approximately 2 m long by 0.2 m wide and grew at temperatures between 55-85oC with the optimum at 78oC. The pH range for growth was 6.0-8.0 with values of near 7.0 being optimal. Growth on cellobiose produced the fastest specific growth rates at 0.75 hr-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, sorbital, 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 l batch fermentations. The G+C content of the DNA was 35 mol% and sequence analysis of the small subunit ribosomal RNA 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 OB47T is the type stain (ATCC = ____, JCM = ____).

  1. Thermophilic anaerobic co-digestion of sewage sludge with grease waste: Effect of long chain fatty acids in the methane yield and its dewatering properties

    International Nuclear Information System (INIS)

    Highlights: • Thermophilic anaerobic codigestion of sewage sludge and grease waste (GW) doubles methane yield. • High GW doses in the influent leads to instability and LCFA accumulation in the effluent. • GW addition promotes acetoclastic activity whilst worsening the hydrogenothrophic activity. • The mesophilic codigestion with GW performs better than the thermophilic one. - Abstract: Thermophilic co-digestion of sewage sludge with three different doses of trapped grease waste (GW) from the pre-treatment of a WWTP has been assessed in a CSTR bench-scale reactor. After adding 12% and 27% of grease waste (on COD basis), the organic loading rate increased from 2.2 to 2.3 and 2.8 kgCOD m−3 d−1 respectively, and the methane yield increased 1.2 and 2.2 times. Further GW increase (37% on COD basis) resulted in an unstable methane yield and in long chain fatty acids (LCFA) accumulation. Although this inestability, the presence of volatile fatty acids in the effluent was negligible, showing good adaptation to fats of the thermophilic biomass. Nevertheless, the presence of LCFA in the effluent worsens its dewatering properties. Specific methanogenic activity tests showed that the addition of grease waste ameliorates the acetoclastic activity in detriment of the hydrogenotrophic activity, and suggests that the tolerance to LCFA can be further enhanced by slowly increasing the addition of lipid-rich materials

  2. Microbial community structure of a pilot-scale thermophilic anaerobic digester treating poultry litter.

    Science.gov (United States)

    Smith, Ami M; Sharma, Deepak; Lappin-Scott, Hilary; Burton, Sara; Huber, David H

    2014-03-01

    The microbial community structure of a stable pilot-scale thermophilic continuous stirred tank reactor digester stabilized on poultry litter was investigated. This 40-m(3) digester produced biogas with 57% methane, and chemical oxygen demand removal of 54%. Bacterial and archaeal diversity were examined using both cloning and pyrosequencing that targeted 16S rRNA genes. The bacterial community was dominated by phylum Firmicutes, constituting 93% of the clones and 76% of the pyrotags. Of the Firmicutes, class Clostridia (52% pyrotags) was most abundant followed by class Bacilli (13% pyrotags). The bacterial libraries identified 94 operational taxonomic units (OTUs) and pyrosequencing identified 577 OTUs at the 97% minimum similarity level. Fifteen OTUs were dominant (≥2% abundance), and nine of these were novel unclassified Firmicutes. Several of the dominant OTUs could not be classified more specifically than Clostridiales, but were most similar to plant biomass degraders, including Clostridium thermocellum. Of the rare pyrotag OTUs (99% of the archaeal clones. Based on the primary methanogen, as well as digester chemistry (high VA and ammonia levels), we propose that bacterial acetate oxidation is the primary pathway in this digester for the control of acetate levels.

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

    Science.gov (United States)

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

    2013-10-01

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

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

    Science.gov (United States)

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

    2013-10-01

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

  5. Dark fermentation of complex waste biomass for biohydrogen production by pretreated thermophilic anaerobic digestate.

    Science.gov (United States)

    Ghimire, Anish; Frunzo, Luigi; Pontoni, Ludovico; d'Antonio, Giuseppe; Lens, Piet N L; Esposito, Giovanni; Pirozzi, Francesco

    2015-04-01

    The Biohydrogen Potential (BHP) of six different types of waste biomass typical for the Campania Region (Italy) was investigated. Anaerobic sludge pre-treated with the specific methanogenic inhibitor sodium 2-bromoethanesulfonic acid (BESA) was used as seed inoculum. The BESA pre-treatment yielded the highest BHP in BHP tests carried out with pre-treated anaerobic sludge using potato and pumpkin waste as the substrates, in comparison with aeration or heat shock pre-treatment. The BHP tests carried out with different complex waste biomass showed average BHP values in a decreasing order from potato and pumpkin wastes (171.1 ± 7.3 ml H2/g VS) to buffalo manure (135.6 ± 4.1 ml H2/g VS), dried blood (slaughter house waste, 87.6 ± 4.1 ml H2/g VS), fennel waste (58.1 ± 29.8 ml H2/g VS), olive pomace (54.9 ± 5.4 ml H2/g VS) and olive mill wastewater (46.0 ± 15.6 ml H2/g VS). The digestate was analyzed for major soluble metabolites to elucidate the different biochemical pathways in the BHP tests. These showed the H2 was produced via mixed type fermentation pathways. PMID:25617867

  6. Dark fermentation of complex waste biomass for biohydrogen production by pretreated thermophilic anaerobic digestate.

    Science.gov (United States)

    Ghimire, Anish; Frunzo, Luigi; Pontoni, Ludovico; d'Antonio, Giuseppe; Lens, Piet N L; Esposito, Giovanni; Pirozzi, Francesco

    2015-04-01

    The Biohydrogen Potential (BHP) of six different types of waste biomass typical for the Campania Region (Italy) was investigated. Anaerobic sludge pre-treated with the specific methanogenic inhibitor sodium 2-bromoethanesulfonic acid (BESA) was used as seed inoculum. The BESA pre-treatment yielded the highest BHP in BHP tests carried out with pre-treated anaerobic sludge using potato and pumpkin waste as the substrates, in comparison with aeration or heat shock pre-treatment. The BHP tests carried out with different complex waste biomass showed average BHP values in a decreasing order from potato and pumpkin wastes (171.1 ± 7.3 ml H2/g VS) to buffalo manure (135.6 ± 4.1 ml H2/g VS), dried blood (slaughter house waste, 87.6 ± 4.1 ml H2/g VS), fennel waste (58.1 ± 29.8 ml H2/g VS), olive pomace (54.9 ± 5.4 ml H2/g VS) and olive mill wastewater (46.0 ± 15.6 ml H2/g VS). The digestate was analyzed for major soluble metabolites to elucidate the different biochemical pathways in the BHP tests. These showed the H2 was produced via mixed type fermentation pathways.

  7. Chemical Hydrolysis and Thermophilic Anaerobic Digestion of Organic Fraction of Municipal Solid Waste

    Directory of Open Access Journals (Sweden)

    Yosvany Díaz Domínguez

    2014-03-01

    Full Text Available The hydrolysis of the macromolecules that compose the organic fraction of municipal solid waste canbe taken for chemical, physical and biological methods, having all as aim the unfolding of the complexmolecules in simplier monomer. Thereby the degradation of organic matter is enhanced and resultsmore efficient the process of biogas via anaerobic. Chemical pretreatments were employed in the workusing sodium hydroxide (NaOH and hydrogen peroxide (H2O2 as reagents.The soluble chemicaloxygen demand (COD, the maximum methane yield and the methane rates production were used toevaluate the pretreatment actions. The degradation of the waste was able to be increased by allowinga comparative analysis to determine the best working conditions for this stage and subsequently itsimpact in the generation of biogas, methane specifically.

  8. Ethanol and hydrogen production by two thermophilic, anaerobic bacteria isolated from Icelandic geothermal areas.

    Science.gov (United States)

    Koskinen, Perttu E P; Beck, Steinar R; Orlygsson, Jóhann; Puhakka, Jaakko A

    2008-11-01

    Microbial fermentations are potential producers of sustainable energy carriers. In this study, ethanol and hydrogen production was studied by two thermophilic bacteria (strain AK15 and AK17) isolated from geothermal springs in Iceland. Strain AK15 was affiliated with Clostridium uzonii (98.8%), while AK17 was affiliated with Thermoanaerobacterium aciditolerans (99.2%) based on the 16S rRNA gene sequence analysis. Both strains fermented a wide variety of sugar residues typically found in lignocellulosic materials, and some polysaccharides. In the batch cultivations, strain AK17 produced ethanol from glucose and xylose fermentations of up to 1.6 mol-EtOH/mol-glucose (80% of the theoretical maximum) and 1.1 mol-EtOH/mol-xylose (66%), respectively. The hydrogen yields by AK17 were up to 1.2 mol-H2/ mol-glucose (30% of the theoretical maximum) and 1.0 mol-H2/mol-xylose (30%). The strain AK15 produced hydrogen as the main fermentation product from glucose (up to 1.9 mol-H2/mol-glucose [48%]) and xylose (1.1 mol-H2/mol-xylose [33%]). The strain AK17 tolerated exogenously added ethanol up to 4% (v/v). The ethanol and hydrogen production performance from glucose by a co-culture of the strains AK15 and AK17 was studied in a continuous-flow bioreactor at 60 degrees C. Stable and continuous ethanol and hydrogen co-production was achieved with ethanol yield of 1.35 mol-EtOH/mol-glucose, and with the hydrogen production rate of 6.1 mmol/h/L (H2 yield of 0.80 mol-H2/mol-glucose). PCR-DGGE analysis revealed that the AK17 became the dominant bacterium in the bioreactor. In conclusion, strain AK17 is a promising strain for the co-production of ethanol and hydrogen with a wide substrate utilization spectrum, relatively high ethanol tolerance, and ethanol yields among the highest reported for thermoanaerobes.

  9. Thermotoga profunda sp. nov. and Thermotoga caldifontis sp. nov., anaerobic thermophilic bacteria isolated from terrestrial hot springs.

    Science.gov (United States)

    Mori, Koji; Yamazoe, Atsushi; Hosoyama, Akira; Ohji, Shoko; Fujita, Nobuyuki; Ishibashi, Jun-ichiro; Kimura, Hiroyuki; Suzuki, Ken-ichiro

    2014-06-01

    Two thermophilic, strictly anaerobic, Gram-negative bacteria, designated strains AZM34c06(T) and AZM44c09(T), were isolated from terrestrial hot springs in Japan. The optimum growth conditions for strain AZM34c06(T) were 60 °C, pH 7.4 and 0% additional NaCl, and those for strain AZM44c09(T) were 70 °C, pH 7.4 and 0% additional NaCl. Complete genome sequencing was performed for both strains, revealing genome sizes of 2.19 Mbp (AZM34c06(T)) and 2.01 Mbp (AZM44c09(T)). Phylogenetic analyses based on 16S rRNA gene sequences and the concatenated predicted amino acid sequences of 33 ribosomal proteins showed that both strains belonged to the genus Thermotoga. The closest relatives of strains AZM34c06(T) and AZM44c09(T) were the type strains of Thermotoga lettingae (96.0% similarity based on the 16S rRNA gene and 84.1% similarity based on ribosomal proteins) and Thermotoga hypogea (98.6 and 92.7% similarity), respectively. Using blast, the average nucleotide identity was 70.4-70.5% when comparing strain AZM34c06(T) and T. lettingae TMO(T) and 76.6% when comparing strain AZM44c09(T) and T. hypogea NBRC 106472(T). Both values are far below the 95% threshold value for species delineation. In view of these data, we propose the inclusion of the two isolates in the genus Thermotoga within two novel species, Thermotoga profunda sp. nov. (type strain AZM34c06(T) = NBRC 106115(T) = DSM 23275(T)) and Thermotoga caldifontis sp. nov. (type strain AZM44c09(T) = NBRC 106116(T) = DSM 23272(T)).

  10. Themoanaerobacterium calidifontis sp. nov., a novel anaerobic, thermophilic, ethanol-producing bacterium from hot springs in China.

    Science.gov (United States)

    Shang, Shu-mei; Qian, Long; Zhang, Xu; Li, Kun-zhi; Chagan, Irbis

    2013-06-01

    A novel thermophilic Gram staining positive strain Rx1 was isolated from hot springs in Baoshan of Yunnan Province, China. The strain was characterized as a hemicellulose-decomposing obligate anaerobe bacterium that is rod-shaped (diameter: 0.5-0.7 μm; length: 2.0-6.7 μm), spore-forming, and motile. Its growth temperature range is 38-68 °C (optimum 50-55 °C) and pH range is 4.5-8.0 (optimum 7.0). The maximum tolerance concentration of NaCl was 3 %. Rx1 converted thiosulfate to elemental sulfur and reduced sulfite to hydrogen sulfide. The bacterium grew by utilizing xylan and starch, as well as a wide range of monosaccharide and polysaccharides, including glucose and xylose. The main products of fermentation were ethanol, lactate, acetate, CO2, and H2. The maximum xylanase activity in the culture supernatant after 30 h of incubation at 55 °C was 16.2 U/ml. Rx1 DNA G + C content was 36 mol %. 16S rRNA gene sequence analysis indicated that strain Rx1 belonged to the genus Thermoanaerobacterium of the family 'Thermoanaerobacteriaceae' (Firmicutes), with Thermoanaerobacterium aciditolerans 761-119 (99.2 % 16S rRNA gene sequence similarity) being its closest relative. DNA-DNA hybridization between Rx1 and T. aciditolerans 761-119 showed 36 % relatedness. Based on its physiological and biochemical tests and DNA-DNA hybridization analyses, the isolate is considered to represent a novel species in the genus Thermoanaerobacterium, for which the name Thermoanaerobacterium calidifontis sp. nov. is proposed, with the type strain is Rx1 (=JCM 18270 = CCTCC M 2011109).

  11. Ethanol production from wet-exploded wheat straw hydrolysate by thermophilic anaerobic bacterium Thermoanaerobacter BG1L1 in a continuous immobilized reactor

    DEFF Research Database (Denmark)

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

    2008-01-01

    to sugar mixtures of glucose and xylose ranging from 12 to 41 g/l. The organism, thermophilic anaerobic bacterium Thermoanaerobacter BG1L1, exhibited significant resistance to high levels of acetic acid (up to 10 g/l) and other metabolic inhibitors present in the hydrolysate. Although the hydrolysate...... was not detoxified, ethanol yield in a range of 0.39-0.42 g/g was obtained. Overall, sugar efficiency to ethanol was 68-76%. The reactor was operated continuously for approximately 143 days, and no contamination was seen without the use of any agent for preventing bacterial infections. The tested microorganism has...

  12. 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. PMID:15246444

  13. Long-chain fatty acids inhibition and adaptation process in anaerobic thermophilic digestion: Batch tests, microbial community structure and mathematical modelling

    DEFF Research Database (Denmark)

    Paltsi, Jordi; Illa, J.; Prenafeta-Boldu, F.X.;

    2010-01-01

    . Population profiles of eubacterial and archaeal 16S rDNA genes revealed that no significant shift on microbial community composition took place upon biomass exposure to LCFA. DNA sequencing of predominant DGGE bands showed close phylogenetic affinity to ribotypes characteristic from specific beta......Biomass samples taken during the continuous operation of thermophilic anaerobic digestors fed with manure and exposed to successive inhibitory pulses of long-chain fatty acids (LCFA) were characterized in terms of specific metabolic activities and 16S rDNA DGGE profiling of the microbial community...... structure. Improvement of hydrogenotrophic and acidogenic (beta-oxidation) activity rates was detected upon successive LCFA pulses, while different inhibition effects over specific anaerobic trophic groups were observed. Bioreactor recovery capacity and biomass adaptation to LCFA inhibition were verified...

  14. Thermophilic sulfate reduction and methanogenesis with methanol in a high rate anaerobic reactor

    Energy Technology Data Exchange (ETDEWEB)

    Weijma, J.; Stams, A.J.M.; Pol, L.W.H.; Lettinga, G.

    2000-02-05

    Sulfate reduction outcompeted methanogenesis at 65 C and pH 7.5 in methanol and sulfate-fed expanded granular sludge bed reactors operated at hydraulic retention times (HRT) of 14 and 2.5 h, both under methanol-limiting and methanol-overloading conditions. After 100 and 50 days for the reactors operated at 14 and 3.5 h, respectively, sulfide production accounted for 80% of the methanol-COD consumed by the sludge. The specific methanogenic activity on methanol of the sludge from a reactor operated at HRTs of down to 3.5 h for a period of 4 months gradually decreased from 0.83 gCOD {sm_bullet} gVSS{sup {minus}1} {sm_bullet} day{sup {minus}1} at the start to a value of less than 0.05 gCOD {sm_bullet} gVSS{sup {minus}1} {sm_bullet} day{sup {minus}1}, showing that the relative number of methanogens decreased and eventually became very low. By contrast, the increase of the specific sulfidogenic activity of sludge from 0.22 gCOD {sm_bullet} gVSS{sup {minus}1} {sm_bullet} day{sup {minus}1} to a final value of 1.05 gCOD {sm_bullet} gVSS{sup {minus}1} {sm_bullet} day{sup {minus}1} showed that sulfate reducing bacteria were enriched. Methanol degradation by a methanogenic culture obtained from a reactor by serial dilution of the sludge was inhibited in the presence of vancomycin, indicating that methanogenesis directly from methanogenic culture obtained from a reactor by serial dilution of the sludge was inhibited in the presence of vancomycin, indicating that methanogenesis directly from methanol was not important. H{sub 2}/CO{sub 2} and formate, but not acetate, were degraded to methane in the presence of vancomycin. These results indicated that methanol degradation to methane occurs via the intermediates H{sub 2}/CO{sub 2} and formate. The high and low specific methanogenic activity of sludge on H{sub 2}/CO{sub 2} and formate, respectively, indicated that the former substrate probably acts as the main electron donor for the methanogens during methanol degradation. As

  15. Fervidicola ferrireducens gen. nov., sp. nov., a thermophilic anaerobic bacterium from geothermal waters of the Great Artesian Basin, Australia.

    Science.gov (United States)

    Ogg, Christopher D; Patel, Bharat K C

    2009-05-01

    A strictly anaerobic, thermophilic bacterium, designated strain Y170(T), was isolated from a microbial mat colonizing thermal waters of a run-off channel created by the free-flowing waters of a Great Artesian Basin (GAB) bore well (New Lorne bore; registered number 17263). Cells of strain Y170(T) were slightly curved rods (1.2-12x0.8-1.1 mum) and stained Gram-negative. The strain grew optimally in tryptone-yeast extract-glucose medium at 70 degrees C (temperature range for growth was 55-80 degrees C) and pH 7 (pH range for growth was 5-9). Strain Y170(T) grew poorly on yeast extract as a sole carbon source, but not on tryptone (0.2 %). Yeast extract could not be replaced by tryptone and was obligately required for growth on tryptone, peptone, glucose, fructose, galactose, cellobiose, mannose, sucrose, xylose, mannitol, formate, pyruvate, Casamino acids and threonine. No growth was observed on arabinose, lactose, maltose, raffinose, chitin, xylan, pectin, starch, acetate, benzoate, lactate, propionate, succinate, myo-inositol, ethanol, glycerol, amyl media, aspartate, leucine, glutamate, alanine, arginine, serine and glycine. End products detected from glucose fermentation were acetate, ethanol and presumably CO(2) and H(2). Iron(III), manganese(IV), thiosulfate and elemental sulfur, but not sulfate, sulfite, nitrate or nitrite, were used as electron acceptors in the presence of 0.2 % yeast extract. Iron(III) in the form of amorphous Fe(III) oxhydroxide and Fe(III) citrate was also reduced in the presence of tryptone, peptone and Casamino acids, but not with chitin, xylan, pectin, formate, starch, pyruvate, acetate, benzoate, threonine, lactate, propionate, succinate, inositol, ethanol, glycerol, mannitol, aspartate, leucine, glutamate, alanine, arginine, serine or glycine. Strain Y170(T) was not able to utilize molecular hydrogen and/or carbon dioxide in the presence or absence of iron(III). Chloramphenicol, streptomycin, tetracycline, penicillin and ampicillin and

  16. Biohydrogen production from desugared molasses (DM) using thermophilic mixed cultures immobilized on heat treated anaerobic sludge granules

    DEFF Research Database (Denmark)

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

    2011-01-01

    Hydrogen production from desugared molasses (DM) was investigated in both batch and continuous reactors using thermophilic mixed cultures enriched from digested manure by load shock (loading with DM concentration of 50.1 g-sugar/L) to suppress methanogens. H2 gas, free of methane, was produced du...

  17. FERMENTATION OF INULIN BY CLOSTRIDIUM-THERMOSUCCINOGENES SP-NOV, A THERMOPHILIC ANAEROBIC BACTERIUM ISOLATED FROM VARIOUS HABITATS

    NARCIS (Netherlands)

    DRENT, WJ; LAHPOR, GA; WIEGANT, WM; GOTTSCHAL, JC

    1991-01-01

    Four closely related strains of thermophilic bacteria were isolated via enrichment in batch and continuous culture with inulin as the sole source of carbon and energy by using inoculations from various sources. These new strains were isolated from beet pulp from a sugar refinery, soil around a Jerus

  18. Enrichment and detection of microorganisms involved in direct and indirect methanogenesis from methanol in an anaerobic thermophilic bioreactor

    NARCIS (Netherlands)

    Roest, de K.; Altinbas, M.; Paulo, P.L.; Heilig, H.G.H.J.; Akkermans, A.D.L.; Smidt, H.; Vos, de W.M.; Stams, A.J.M.

    2005-01-01

    To gain insight into the microorganisms involved in direct and indirect methane formation from methanol in a laboratory-scale thermophilic (55°C) methanogenic bioreactor, reactor sludge was disrupted and serial dilutions were incubated in specific growth media containing methanol and possible interm

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

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Ahring, Birgitte Kiær

    1995-01-01

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

  20. Effect of polyvinyl alcohol hydrogel as a biocarrier on volatile fatty acids production of a two-stage thermophilic anaerobic membrane bioreactor.

    Science.gov (United States)

    Chaikasem, Supawat; Abeynayaka, Amila; Visvanathan, Chettiyappan

    2014-09-01

    This work studied the effect of polyvinyl alcohol hydrogel (PVA-gel) beads, as an effective biocarrier for volatile fatty acid (VFA) production in hydrolytic reactor of a two-stage thermophilic anaerobic membrane bioreactor (TAnMBR). The two-stage TAnMBR, treating synthetic high strength particulate wastewater with influent chemical oxygen demand (COD) [16.4±0.8 g/L], was operated at 55 °C. Under steady state conditions, the reactor was operated at an organic loading rate of 8.2±0.4 kg COD/m(3) d. Operational performance of the system was monitored by assessing VFA composition and quantity, methane production and COD removal efficiency. Increment of VFA production was observed with PVA-gel addition. Hydrolytic effluent contained large amount of acetic acid and n-butyric acid. However, increase in VFA production adversely affected the methanogenic reactor performance due to lack of methanogenic archaea. PMID:24803272

  1. Elucidation of the thermophilic phenol biodegradation pathway via benzoate during the anaerobic digestion of municipal solid waste

    OpenAIRE

    Hoyos, C.; Hoffmann, M; Guenne, A.; Mazéas, L.

    2014-01-01

    International audience Anaerobic digestion makes it possible to valorize municipal solid waste (MSW) into biogas and digestate which are, respectively, a renewable energy source and an organic amendment for soil. Phenols are persistent pollutants present in MSW that can inhibit the anaerobic digestion process and have a toxic effect on microbiota if they are applied to soil together with digestate. It is then important to define the operational conditions of anaerobic digestion which allow...

  2. The Start-up of Hybrid, Anaerobic up-flow Sludge Blanket (HUASB under a Range of Mesophiclic and Thermophilic Temperatures

    Directory of Open Access Journals (Sweden)

    S. A. Habeeb

    2011-07-01

    Full Text Available We have examined the effect of gradual increase of the temperature on the performance of anaerobic process of palm oil mill effluent (POME, and sludge granules development. Two hybrid up-flow anaerobic sludge blanket (HUASB reactors R1 and R2 were employed to be run at 27±2 and 37±1°C, respectively. R1 was kept at room temperature for the whole experiment, where the temperature of R2 was increased up to 49ºC (3ºC after every steady-state occurrence. Maximum COD removal of 91% was obtained in R2 at optimum temperature of 46°C, while 84% was recorded in R1. Additional parameters were applied to evaluate the performance of the process, i.e. total suspended solids (TSS, Turbidity, and Color. The imaging of sludge aggregate has revealed the effect of temperature on granulation development during the experiment. Throughout the operation period, it can be seen that the microbial growth rate was significantly affected by temperature. Hence, the use of HUASB reactor could be productively implemented for POME treatment as an efficient system under the mesophilic and thermophilic temperatures.

  3. Comparison of two-stage thermophilic (68 degrees C/55 degrees C) anaerobic digestion with one-stage thermophilic (55 degrees C) digestion of cattle manure

    DEFF Research Database (Denmark)

    Nielsen, H.B.; Mladenovska, Zuzana; Westermann, Peter;

    2004-01-01

    A two-stage 68degreesC/55degreesC anaerobic degradation process for treatment of cattle manure was studied. In batch experiments, an increase of the specific methane yield, ranging from 24% to 56%, was obtained when cattle manure and its fractions (fibers and liquid) were pretreated at 68degrees......C for periods of 36, 108, and 168 h, and subsequently digested at 55degreesC. In a lab-scale experiment, the performance of a two-stage reactor system, consisting of a digester operating at 68degreesC with a hydraulic retention time (HRT) of 3 days, connected to a 55degreesC reactor with 12-day HRT, was...... compared with a conventional single-stage reactor running at 55degreesC with 15-days HRT. When an organic loading of 3 g volatile solids (VS) per liter per day was applied, the two-stage setup had a 6% to 8% higher specific methane yield and a 9% more effective VS-removal than the conventional single...

  4. Quantifying Contribution of Synthrophic Acetate Oxidation to Methane Production in Thermophilic Anaerobic Reactors by Membrane Inlet Mass Spectrometry

    DEFF Research Database (Denmark)

    Mulat, Daniel Girma; Ward, Alastair James; Adamsen, Anders Peter S.;

    2014-01-01

    a new approach for online quantification of the relative contribution of methanogenesis pathways to methane production with a time resolution shorter than one minute. The observed contribution of SAO-HM to methane production under the tested conditions challenges the current widely accepted anaerobic...

  5. Continuous Ethanol Fermentation of Pretreated Lignocellulosic Biomasses, Waste Biomasses, Molasses and Syrup Using the Anaerobic, Thermophilic Bacterium Thermoanaerobacter italicus Pentocrobe 411.

    Science.gov (United States)

    Andersen, Rasmus Lund; Jensen, Karen Møller; Mikkelsen, Marie Just

    2015-01-01

    Lignocellosic ethanol production is now at a stage where commercial or semi-commercial plants are coming online and, provided cost effective production can be achieved, lignocellulosic ethanol will become an important part of the world bio economy. However, challenges are still to be overcome throughout the process and particularly for the fermentation of the complex sugar mixtures resulting from the hydrolysis of hemicellulose. Here we describe the continuous fermentation of glucose, xylose and arabinose from non-detoxified pretreated wheat straw, birch, corn cob, sugar cane bagasse, cardboard, mixed bio waste, oil palm empty fruit bunch and frond, sugar cane syrup and sugar cane molasses using the anaerobic, thermophilic bacterium Thermoanaerobacter Pentocrobe 411. All fermentations resulted in close to maximum theoretical ethanol yields of 0.47-0.49 g/g (based on glucose, xylose, and arabinose), volumetric ethanol productivities of 1.2-2.7 g/L/h and a total sugar conversion of 90-99% including glucose, xylose and arabinose. The results solidify the potential of Thermoanaerobacter strains as candidates for lignocellulose bioconversion.

  6. Enhancement in hydrogen production by thermophilic anaerobic co-digestion of organic fraction of municipal solid waste and sewage sludge--optimization of treatment conditions.

    Science.gov (United States)

    Tyagi, Vinay Kumar; Angériz Campoy, Rubén; Álvarez-Gallego, C J; Romero García, L I

    2014-07-01

    Batch dry-thermophilic anaerobic co-digestion (55°C) of organic fraction of municipal solid waste (OFMSW) and sewage sludge (SS) for hydrogen production was studied under several sludge combinations (primary sludge, PS; waste activated sludge, WAS; and mixed sludge, MS), TS concentrations (10-25%) and mixing ratios of OFMSW and SS (1:1, 2.5:1, 5:1, 10:1). The co-digestion of OFMSW and SS showed a 70% improvement in hydrogen production rate over the OFMSW fermentation only. The co-digestion of OFMSW with MS showed 47% and 115% higher hydrogen production potential as compared with OFMSW+PS and OFMSW+WAS, respectively. The maximum hydrogen yield of 51 mL H2/g VS consumed was observed at TS concentration of 20% and OFMSW to MS mixing ratio of 5:1, respectively. The acetic and butyric acids were the main acids in VFAs evolution; however, the higher butyric acid evolution indicated that the H2 fermentation was butyrate type fermentation.

  7. Thermophilic anaerobic digestion of coffee grounds with and without waste activated sludge as co-substrate using a submerged AnMBR: system amendments and membrane performance.

    Science.gov (United States)

    Qiao, Wei; Takayanagi, Kazuyuki; Shofie, Mohammad; Niu, Qigui; Yu, Han Qing; Li, Yu-You

    2013-12-01

    Coffee grounds are deemed to be difficult for degradation by thermophilic anaerobic process. In this research, a 7 L AnMBR accepting coffee grounds was operated for 82 days and failed with pH dropping to 6.6. The deficiency of micronutrients in the reactor was identified. The system was recovered by supplying micronutrient, pH adjustment and influent ceasing for 22 days. In the subsequent 160 days of co-digestion experiment, waste activated sludge (15% in the mixture) was mixed into coffee grounds. The COD conversion efficiency of 67.4% was achieved under OLR of 11.1 kg-COD/m(3) d and HRT of 20 days. Tannins was identified affecting protein degradation by a batch experiment. Quantitative supplements of NH4HCO3 (0.12 g-N/g-TSin) were effective to maintain alkalinity and pH. The solid concentration in the AnMBR reached 75 g/L, but it did not significantly affect membrane filtration under a flux of 5.1 L/m(2) h. Soluble carbohydrate, lipid and protein were partially retained by the membrane. PMID:24177158

  8. Continuous Ethanol Fermentation of Pretreated Lignocellulosic Biomasses, Waste Biomasses, Molasses and Syrup Using the Anaerobic, Thermophilic Bacterium Thermoanaerobacter italicus Pentocrobe 411.

    Directory of Open Access Journals (Sweden)

    Rasmus Lund Andersen

    Full Text Available Lignocellosic ethanol production is now at a stage where commercial or semi-commercial plants are coming online and, provided cost effective production can be achieved, lignocellulosic ethanol will become an important part of the world bio economy. However, challenges are still to be overcome throughout the process and particularly for the fermentation of the complex sugar mixtures resulting from the hydrolysis of hemicellulose. Here we describe the continuous fermentation of glucose, xylose and arabinose from non-detoxified pretreated wheat straw, birch, corn cob, sugar cane bagasse, cardboard, mixed bio waste, oil palm empty fruit bunch and frond, sugar cane syrup and sugar cane molasses using the anaerobic, thermophilic bacterium Thermoanaerobacter Pentocrobe 411. All fermentations resulted in close to maximum theoretical ethanol yields of 0.47-0.49 g/g (based on glucose, xylose, and arabinose, volumetric ethanol productivities of 1.2-2.7 g/L/h and a total sugar conversion of 90-99% including glucose, xylose and arabinose. The results solidify the potential of Thermoanaerobacter strains as candidates for lignocellulose bioconversion.

  9. Changes in microbial community during hydrogen and methane production in two-stage thermophilic anaerobic co-digestion process from biowaste.

    Science.gov (United States)

    Zahedi, S; Solera, R; Micolucci, F; Cavinato, C; Bolzonella, D

    2016-03-01

    In this paper, the microbial community in a two-phase thermophilic anaerobic co-digestion process was investigated for its role in hydrogen and methane production, treating waste activated sludge and treating the organic fraction of municipal solid waste. In the acidogenic phase, in which hydrogen is produced, Clostridium sp. clusters represented 76% of total Firmicutes. When feeding the acidogenic effluent into the methanogenic reactors, these acidic conditions negatively influenced methanogenic microorganisms: Methanosaeta sp., (Methanobacteriales, Methanomicrobiales, Methanococcales) decreased by 75%, 50%, 38% and 52%, respectively. At the same time, methanogenic digestion lowered the numbers of Clostridium sp. clusters due to both pH increasing and substrate reduction, and an increase in both Firmicutes genera (non Clostridium) and methanogenic microorganisms, especially Methanosaeta sp. (208%). This was in accordance with the observed decrease in acetic (98%) and butyric (100%) acid contents. To ensure the activity of the acetate-utilizing methanogens (AUM) and the acetogens, high ratios of H2-utilizing methanogens (HUM)/AUM (3.6) were required. PMID:26810032

  10. Optimization of separate hydrogen and methane production from cassava wastewater using two-stage upflow anaerobic sludge blanket reactor (UASB) system under thermophilic operation.

    Science.gov (United States)

    Intanoo, Patcharee; Rangsanvigit, Pramoch; Malakul, Pomthong; Chavadej, Sumaeth

    2014-12-01

    The objective of this study was to investigate the separate hydrogen and methane productions from cassava wastewater by using a two-stage upflow anaerobic sludge blanket (UASB) system under thermophilic operation. Recycle ratio of the effluent from methane bioreactor-to-feed flow rate was fixed at 1:1 and pH of hydrogen UASB unit was maintained at 5.5. At optimum COD loading rate of 90 kg/m3 d based on the feed COD load and hydrogen UASB volume, the produced gas from the hydrogen UASB unit mainly contained H2 and CO2 which provided the maximum hydrogen yield (54.22 ml H2/g COD applied) and specific hydrogen production rate (197.17 ml/g MLVSSd). At the same optimum COD loading rate, the produced gas from the methane UASB unit mainly contained CH4 and CO2 without H2 which were also consistent with the maximum methane yield (164.87 ml CH4/g COD applied) and specific methane production rate (356.31 ml CH4/g MLVSSd). The recycling operation minimized the use of NaOH for pH control in hydrogen UASB unit. PMID:25306229

  11. Continuous Ethanol Fermentation of Pretreated Lignocellulosic Biomasses, Waste Biomasses, Molasses and Syrup Using the Anaerobic, Thermophilic Bacterium Thermoanaerobacter italicus Pentocrobe 411.

    Science.gov (United States)

    Andersen, Rasmus Lund; Jensen, Karen Møller; Mikkelsen, Marie Just

    2015-01-01

    Lignocellosic ethanol production is now at a stage where commercial or semi-commercial plants are coming online and, provided cost effective production can be achieved, lignocellulosic ethanol will become an important part of the world bio economy. However, challenges are still to be overcome throughout the process and particularly for the fermentation of the complex sugar mixtures resulting from the hydrolysis of hemicellulose. Here we describe the continuous fermentation of glucose, xylose and arabinose from non-detoxified pretreated wheat straw, birch, corn cob, sugar cane bagasse, cardboard, mixed bio waste, oil palm empty fruit bunch and frond, sugar cane syrup and sugar cane molasses using the anaerobic, thermophilic bacterium Thermoanaerobacter Pentocrobe 411. All fermentations resulted in close to maximum theoretical ethanol yields of 0.47-0.49 g/g (based on glucose, xylose, and arabinose), volumetric ethanol productivities of 1.2-2.7 g/L/h and a total sugar conversion of 90-99% including glucose, xylose and arabinose. The results solidify the potential of Thermoanaerobacter strains as candidates for lignocellulose bioconversion. PMID:26295944

  12. High organic loading rate on thermophilic hydrogen production and metagenomic study at an anaerobic packed-bed reactor treating a residual liquid stream of a Brazilian biorefinery.

    Science.gov (United States)

    Ferraz Júnior, Antônio Djalma Nunes; Etchebehere, Claudia; Zaiat, Marcelo

    2015-06-01

    This study evaluated the influence of a high organic loading rate (OLR) on thermophilic hydrogen production at an up-flow anaerobic packed-bed reactor (APBR) treating a residual liquid stream of a Brazilian biorefinery. The APBR, filled with low-density polyethylene, was operated at an OLR of 84.2 kg-COD m(-3) d(-1). This value was determined in a previous study. The maximum values of hydrogen production and yield were 5,252.6 mL-H2 d(-1) and 3.7 mol-H2 mol(-1)(total carbohydrates), respectively. However, whereas the OLR remained constant, the specific organic load rate (sOLR) decreased throughout operation from 1.38 to 0.72 g-Total carbohydratesg-VS(-1) h(-1), this decrease negatively affected hydrogen production. A sOLR of 0.98 g-Total carbohydratesg-VS(-1) h(-1) was optimal for hydrogen production. The microbial community was studied using 454-pyrosequencing analysis. Organisms belonging to the genera Caloramator, Clostridium, Megasphaera, Oxobacter, Thermoanaerobacterium, and Thermohydrogenium were detected in samples taken from the reactor at operation days 30 and 60, suggesting that these organisms contribute to hydrogen production.

  13. Thermophilic anaerobic co-digestion of organic fraction of municipal solid waste (OFMSW) with food waste (FW): Enhancement of bio-hydrogen production.

    Science.gov (United States)

    Angeriz-Campoy, Rubén; Álvarez-Gallego, Carlos J; Romero-García, Luis I

    2015-10-01

    Bio-hydrogen production from dry thermophilic anaerobic co-digestion (55°C and 20% total solids) of organic fraction of municipal solid waste (OFMSW) and food waste (FW) was studied. OFMSW coming from mechanical-biological treatment plants (MBT plants) presents a low organic matter concentration. However, FW has a high organic matter content but several problems by accumulation of volatile fatty acids (VFAs) and system acidification. Tests were conducted using a mixture ratio of 80:20 (OFSMW:FW), to avoid the aforementioned problems. Different solid retention times (SRTs) - 6.6, 4.4, 2.4 and 1.9 days - were tested. It was noted that addition of food waste enhances the hydrogen production in all the SRTs tested. Best results were obtained at 1.9-day SRT. It was observed an increase from 0.64 to 2.51 L H2/L(reactor) day in hydrogen productivity when SRTs decrease from 6.6 to 1.9 days. However, the hydrogen yield increases slightly from 33.7 to 38 mL H2/gVS(added). PMID:26210142

  14. Changes in microbial community during hydrogen and methane production in two-stage thermophilic anaerobic co-digestion process from biowaste.

    Science.gov (United States)

    Zahedi, S; Solera, R; Micolucci, F; Cavinato, C; Bolzonella, D

    2016-03-01

    In this paper, the microbial community in a two-phase thermophilic anaerobic co-digestion process was investigated for its role in hydrogen and methane production, treating waste activated sludge and treating the organic fraction of municipal solid waste. In the acidogenic phase, in which hydrogen is produced, Clostridium sp. clusters represented 76% of total Firmicutes. When feeding the acidogenic effluent into the methanogenic reactors, these acidic conditions negatively influenced methanogenic microorganisms: Methanosaeta sp., (Methanobacteriales, Methanomicrobiales, Methanococcales) decreased by 75%, 50%, 38% and 52%, respectively. At the same time, methanogenic digestion lowered the numbers of Clostridium sp. clusters due to both pH increasing and substrate reduction, and an increase in both Firmicutes genera (non Clostridium) and methanogenic microorganisms, especially Methanosaeta sp. (208%). This was in accordance with the observed decrease in acetic (98%) and butyric (100%) acid contents. To ensure the activity of the acetate-utilizing methanogens (AUM) and the acetogens, high ratios of H2-utilizing methanogens (HUM)/AUM (3.6) were required.

  15. Thermophilic degradation of cellulosic biomass

    Science.gov (United States)

    Ng, T.; Zeikus, J. G.

    1982-12-01

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

  16. Effect of increased load of high-strength food wastewater in thermophilic and mesophilic anaerobic co-digestion of waste activated sludge on bacterial community structure.

    Science.gov (United States)

    Jang, Hyun Min; Ha, Jeong Hyub; Kim, Mi-Sun; Kim, Jong-Oh; Kim, Young Mo; Park, Jong Moon

    2016-08-01

    In recent years, anaerobic co-digestion (AcoD) has been widely used to improve reactor performance, especially methane production. In this study, we applied two different operating temperatures (thermophilic and mesophilic) and gradually increased the load of food wastewater (FWW) to investigate the bacterial communities during the AcoD of waste activated sludge (WAS) and FWW. As the load of FWW was increased, methane production rate (MPR; L CH4/L d) and methane content (%) in both Thermophilic AcoD (TAcoD) and Mesophilic AcoD (MAcoD) increased significantly; the highest MPR and methane content in TAcoD (1.423 L CH4/L d and 68.24%) and MAcoD (1.233 L CH4/L d and 65.21%) were observed when the FWW mixing ratio was 75%. However, MPR and methane yield in both reactors decreased markedly and methane production in TAcoD ceased completely when only FWW was fed into the reactor, resulting from acidification of the reactor caused by accumulation of organic acids. Pyrosequencing analysis revealed a decrease in bacterial diversity in TAcoD and a markedly different composition of bacterial communities between TAcoD and MAcoD with an increase in FWW load. For example, Bacterial members belonging to two genera Petrotoga (assigned to phylum Thermotogae) and Petrimonas (assigned to phylum Bacteroidetes) became dominant in TAcoD and MAcoD with an increase in FWW load, respectively. In addition, quantitative real-time PCR (qPCR) results showed higher bacterial and archaeal populations (expressed as 16S rRNA gene concentration) in TAcoD than MAcoD with an increase in FWW load and showed maximum population when the FWW mixing ratio was 75% in both reactors. Collectively, this study demonstrated the dynamics of key bacterial communities in TAcoD and MAcoD, which were highly affected by the load of FWW. PMID:27155112

  17. Anaerobic digestion as final step of a cellulosic ethanol biorefinery:

    DEFF Research Database (Denmark)

    Uellendahl, Hinrich; Ahring, Birgitte Kiær

    2010-01-01

    of suspended matter reduced the degradation efficiency. The retention time of the anaerobic system could be reduced from 70 to 7 h by additional removal of suspended matter by clarification. Implementation of the biogas production from the fermentation effluent accounted for about 30% higher carbon utilization...

  18. Genetics of thermophilic bacteria. Final progress report, May 1, 1984--April 30, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Welker, N.E.

    1991-12-31

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

  19. Anaerobic thermophilic bacteria isolated from a Venezuelan oil field and its potential use in microbial improved oil recovery

    Energy Technology Data Exchange (ETDEWEB)

    Trebbau, G.; Fernandez, B.; Marin, A. [INTEVEP S.A., Caracas (Venezuela)

    1995-12-31

    The objective of this work is to determine the ability of indigenous bacteria from a Venezuelan oil field to grow under reservoir conditions inside a porous media, and to produce metabolites capable of recovering residual crude oil. For this purpose, samples of formation waters from a central-eastern Venezuelan oil reservoir were enriched with different carbon sources and a mineral basal media. Formation water was used as a source of trace metals. The enrichments obtained were incubated at reservoir temperature (71{degrees}C), reservoir pressure (1,200 psi), and under anaerobic conditions for both outside and inside porous media (Berea core). Growth and metabolic activity was followed outside porous media by measuring absorbance at 660 nm, increases in pressure, and decreases in pH. Inside porous media bacterial activity was determined by visual examination of the produced waters (gas bubbles and bacterial cells). All the carbohydrates tested outside porous media showed good growth at reservoir conditions. The pH was lowered, gases such as CO{sub 2} and CH{sub 4} were identified by GC. Surface tension was lowered in some enrichments by 30% when compared to controls. Growth was decreased inside porous media, but gases were produced and helped displace oil. In addition, 10% residual oil was recovered from the Berea core. Mathematical modeling was applied to the laboratory coreflood experiment to evaluate the reproducibility of the results obtained.

  20. Ammonia-methane two-stage anaerobic digestion of dehydrated waste-activated sludge

    OpenAIRE

    Nakashimada, Yutaka; Ohshima, Yasutaka; Minami, Hisao; Yabu, Hironori; Namba,Yuzaburo; Nishio, Naomichi

    2008-01-01

    In repeated batch-wise thermophilic anaerobic digestion of dehydrated waste-activated sludge with 80% (w/w) water content (DWAS), although methane production reached 30 % of total organic carbon in DWAS in the first run of 15d, it gradually decreased and finally stopped in the subsequent runs together with an increase in ammonia concentration. When the loading of DWAS on anaerobic digestion was investigated, methane production at 30d significantly decreased with the increase in the amount of ...

  1. Sulfate addition as an effective method to improve methane fermentation performance and propionate degradation in thermophilic anaerobic co-digestion of coffee grounds, milk and waste activated sludge with AnMBR.

    Science.gov (United States)

    Li, Qian; Li, Yu-You; Qiao, Wei; Wang, Xiaochang; Takayanagi, Kazuyuki

    2015-06-01

    This study was conducted to investigate the effects of sulfate on propionate degradation and higher organic loading rate (OLR) achievement in a thermophilic AnMBR for 373days using coffee grounds, milk and waste activated sludge (WAS) as the co-substrate. Without the addition of sulfate, the anaerobic system failed at an OLR of 14.6g-COD/L/d, with propionate accumulating to above 2.23g-COD/L, and recovery by an alkalinity supplement was not successful. After sulfate was added into substrates at a COD/SO4(2-) ratio of 200:1 to 350:1, biogas production increased proportionally with OLR increasing from 4.06 to 15.2g-COD/L/d. Propionic acid was maintained at less than 100mg-COD/L due to the effective conversion of propionic acid to methane after the sulfate supplement was added. The long-term stable performance of the AnMBR indicated that adding sulfate was beneficial for the degradation of propionate and achieving a higher OLR under the thermophilic condition. PMID:25791749

  2. 高温CSTR-中温UASB两级厌氧处理木薯酒精废水%Two-stage anaerobic treatment of cassava ethanol wastewater using thermophilic CSTR and mesophilic UASB

    Institute of Scientific and Technical Information of China (English)

    陈金荣; 谢丽; 罗刚; 周琪

    2011-01-01

    Since cassava ethanol wastewater is characterized by high temperature,high solid content and high organism concentration,the two-stage anaerobic treatment using thermophilic continuous stirred tank reactor (CSTR)and mesophilic upflow anaerobic sludge bed (UASB) has been conducted. Experimental results show that when the influent COD loading of thermophilic CSTR is controlled 14 kg/(m3·d) and COD loading of mesophilic UASB reactor is controlled 3 kg/(m3·d) ,the total removal rates of COD,SS,TN and TP are 94% ,96% ,44% and 87% ,respectively, after the two-stage anaerobic treatment.The life cycle of cassava ethanol production and economic benefits of such wastewater treatment are discussed,indicating that two-stage anaerobic treatment process can not only reduce the pollution resulted from cassava ethanol production, but also create economic benefits from the biogas produced in the course of treatment.%针对木薯酒精废水温度、固体含量及有机物浓度高的特点,采用高温CSTR-中温UASB两级厌氧工艺处理木薯酒精废水.小试结果表明,控制高温CSTR进水COD负荷为14 kg/(m3·d),中温UASB COD负荷为3 kg/(m3·d)时,两级厌氧对COD、SS、溶解性TN、溶解性TP的总去除率分别达94%、96%、44%和87%.对木薯酒精生产周期和废水处理经济效益的分析表明,采用两级厌氧工艺处理木薯酒精废水,不仅削减了木薯酒精生产过程中产生的污染物,其处理过程中产生的沼气还带来了一定的经济效益.

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

    OpenAIRE

    Asma Sattar; Chaudhry Arslan; Changying Ji; Sumiyya Sattar; Irshad Ali Mari; Haroon Rashid; Fariha Ilyas

    2016-01-01

    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 i...

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

    Science.gov (United States)

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

    2014-01-01

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

  5. Effect of solid-state NaOH pretreatment on methane production from thermophilic semi-dry anaerobic digestion of rose stalk.

    Science.gov (United States)

    Liang, Yue-Gan; Cheng, Beijiu; Si, You-Bin; Cao, De-Ju; Li, Dao-Lin; Chen, Jian-Feng

    2016-01-01

    The effects of solid-state NaOH pretreatment on the efficiency of methane production from semi-dry anaerobic digestion of rose (Rosa rugosa) stalk were investigated at various NaOH loadings (0, 1, 2, and 4% (w/w)). Methane production, process stability and energy balance were analyzed. Results showed that solid-state NaOH pretreatment significantly improved biogas and methane yields of 30-day anaerobic digestion, with increases from 143.7 mL/g volatile solids (VS) added to 157.1 mL/g VS -192.1 mL/g VS added and from 81.8 mL/g VS added to 88.8 mL/g VS-117.7 mL/g VS added, respectively. Solid-state NaOH pretreatment resulted in anaerobic digestion with higher VS reduction and lower technical digestion time. The 4% NaOH-treated group had the highest methane yield of 117.7 mL/g VS added, which was 144% higher compared to the no NaOH-treated group, and the highest net energy recovery. Higher rate of lignocellulose breakage and higher process stability of anaerobic digestion facilitated methane production in the NaOH-pretreated groups.

  6. Bioaugmentation of a Two-Stage Thermophilic (68°C/55°C) Anaerobic Digestion Concept for Improvement of the Methane Yield From Cattle Manure

    DEFF Research Database (Denmark)

    Bangsø Nielsen, Henrik; Mladenovska, Zuzana; Ahring, Birgitte Kiær

    2007-01-01

    The possibility of improving a two-stage (68°C/55°C) anaerobic digestion concept for treatment of cattle manure was studied. In batch experiments, a 10-24% increase of the specific methane yield from cattle manure and its fractions was obtained, when the substrates were inoculated with bacteria of...... of the two-stage setup....

  7. Effect of carbon monoxide, hydrogen and sulfate on thermophilic (55°C) hydrogenogenic carbon monoxide conversion in two anaerobic bioreactor sludges

    NARCIS (Netherlands)

    Sipma, J.; Meulepas, R.J.W.; Stams, A.J.M.; Lettinga, G.; Lens, P.N.L.

    2004-01-01

    The conversion routes of carbon monoxide (CO) at 55°C by full-scale grown anaerobic sludges treating paper mill and distillery wastewater were elucidated. Inhibition experiments with 2-bromoethanesulfonate (BES) and vancomycin showed that CO conversion was performed by a hydrogenogenic population an

  8. 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.

  9. The effects of micro-aeration on the phylogenetic diversity of microorganisms in a thermophilic anaerobic municipal solid-waste digester.

    Science.gov (United States)

    Tang, Yueqin; Shigematsu, Toru; Ikbal; Morimura, Shigeru; Kida, Kenji

    2004-05-01

    We demonstrated previously that micro-aeration allows construction of an effective thermophilic methane-fermentation system for treatment of municipal solid waste (MSW) without production of H(2)S. In the present study, we compared the microbial communities in a thermophilic MSW digester without aeration and with micro-aeration by fluorescence in situ hybridization (FISH), denaturing gradient gel electrophoresis (DGGE), phylogenetic analysis of libraries of 16S rRNA gene clones and quantitative real-time PCR. Moreover, we studied the activity of sulfate-reducing bacteria (SRB) by analysis of the transcription of the gene for dissimilatory sulfite reductase (dsr). Experiments using FISH revealed that microorganisms belonging to the domain Bacteria dominated in the digester both without aeration and with micro-aeration. Phylogenetic analysis based on 16S rRNA gene and analysis of bacteria by DGGE did not reveal any obvious difference within the microbial communities under the two aeration conditions, and bacteria affiliated with the phylum Firmicutes were dominant. In Archaea, the population of Methanosarcina decreased while the population of Methanoculleus increased as a result of micro-aerations as revealed by the analysis of 16S rRNA gene clones and quantitative real-time PCR. Reverse transcription and PCR (RT-PCR) demonstrated the transcription of dsrA not only in the absence of aeration but also in the presence of micro-aeration, even under conditions where no H(2)S was detected in the biogas. In conclusion, micro-aeration has no obvious effects on the phylogenetic diversity of microorganisms. Furthermore, the activity of SRBs in the digester was not repressed even though the concentration of H(2)S in the biogas was very low under the micro-aeration conditions. PMID:15159157

  10. Effect of different proportions on the thermophilic anaerobic digestion of food waste%不同原料配比对餐饮废弃物高温厌氧发酵的影响

    Institute of Scientific and Technical Information of China (English)

    常国璋; 席新明; 郭康权; 杨秀生

    2012-01-01

    【Objective】The study explored the effect of different proportions of food waste on the thermophilic anaerobic digestion to determine optimal parameter for more utilization of food waste.【Method】The organic ingredients of food waste in Yangling of Shanxi were tested.According to the test,the experiment was conducted with self-manufactured anaerobic equipment from the northwest station of biogas products and equipment quality center of ministry of agriculture.Effect of different proportions of food waste on the thermophilic anaerobic digestion was studied through measuring CH4 content and biogas production.【Result】Characteristics of biogas production in each group were significant.On the 1-3 days of the anaerobic digestion,the accumulative biogas production of group 6(m(rice)∶m(napkin)∶m(meat)=3∶4∶3)was the highest(5 410 mL),while group 11 was the lowest(3 150 mL).The CH4 content of group 3(m(rice)∶m(napkin)∶m(meat)=2∶4∶4)was the highest(16.7%) and the group 29 was the lowest(1.3%).In all days of the anaerobic digestion,the total biogas production(8 400 mL),biogas production rate(140.94 mL/g) and CH4 content(49.9%) of group 10 were the maximum,so proportion of m(rice)∶m(napkin)∶m(meat)=4∶4∶2 is the best.【Conclusion】This study provided optimum parameters for thermophilic anaerobic digestion of food waste,and it demonstrated how to achieve more utilization of food waste.%【目的】探索不同原料配比对餐饮废弃物高温厌氧发酵的影响,为餐饮废弃物最大资源化利用提供理论依据。【方法】用环境监测布点法检测陕西杨凌餐饮废弃物的有机成分含量,根据检测结果,采用农业部西北沼气分中心自行设计的厌氧发酵装置,选取产气量和甲烷含量作为指标,于55℃下考察不同原料配比对餐饮废弃物厌氧发酵的影响。【结果】各处理组产气

  11. Thermophilic two-phase anaerobic digestion of source-sorted organic fraction of municipal solid waste for bio-hythane production: effect of recirculation sludge on process stability and microbiology over a long-term pilot-scale experience.

    Science.gov (United States)

    Giuliano, A; Zanetti, L; Micolucci, F; Cavinato, C

    2014-01-01

    A two-stage thermophilic anaerobic digestion process for the concurrent production of hydrogen and methane through the treatment of the source-sorted organic fraction of municipal solid waste was carried out over a long-term pilot scale experience. Two continuously stirred tank reactors were operated for about 1 year. The results showed that stable production of bio-hythane without inoculum treatment could be obtained. The pH of the dark fermentation reactor was maintained in the optimal range for hydrogen-producing bacteria activity through sludge recirculation from a methanogenic reactor. An average specific bio-hythane production of 0.65 m(3) per kg of volatile solids fed was achieved when the recirculation flow was controlled through an evaporation unit in order to avoid inhibition problems for both microbial communities. Microbial analysis indicated that dominant bacterial species in the dark fermentation reactor are related to the Lactobacillus family, while the population of the methanogenic reactor was mainly composed of Defluviitoga tunisiensis. The archaeal community of the methanogenic reactor shifted, moving from Methanothermobacter-like to Methanobacteriales and Methanosarcinales, the latter found also in the dark fermentation reactor when a considerable methane production was detected. PMID:24901613

  12. Thermoanaerobacterium aotearoense sp. nov., a slightly acidophilic, anaerobic thermophile isolated from various hot springs in New Zealand, and emendation of the genus Thermoanaerobacterium

    Energy Technology Data Exchange (ETDEWEB)

    Shu-Ying Liu; Wiegel, J. [Univ. of Georiga, Athens, GA (United States); Rainey, F.A. [Deutsche Sammlung von Mikroorganismen und Zellkulturen, Braunschweig (Germany)] [and others

    1996-04-01

    Six moderately acidophilic, thermophilic bacterial strains with similar properties were isolated from geothermally heated water and sediment samples collected in New Zealand. These Gram stain-negative but Gram type-positive, rod-shaped bacteria formed oval terminal endospores. The cells were peritrichously flagellated and exhibited tumbling motility. At 60{degrees}C the pH range for growth was 3.8 to 6.8, and the optimum pH was 5.2 when the organisms were grown with xylose. At pH 5.2 the temperature range for growth was 35 to 66{degrees}C, and the optimum temperature was 60 to 63{degrees}C. The fermentation products from flucose or xylose were ethanol, acetate, lactate, CO{sub 2}, and H{sub 2}. The DNA G+C content was 34.5 to 35 mol%. On the basis of properties such as formation of elemental sulfur from thiosulfate, growth at acidic pH values at elevated temperatures, and the results of a 16S rRNA sequence comparison performed with previously validly published species belonging to the genus Thermoanaerobacterium, we propose that strain JW/SL-NZ613{sup T} (T = type strain) and five similar strains isolated from samples collected in New Zealand represent a new species, Thermoanaerobacterium aotearoense. Strain JW/SL-NZ613{sup T} (= DSM 10170) is the type strain of this species.

  13. Releasing the full potential of AIKAN - a dry anaerobic digestion biogas technology. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Joernsgaerd, B.; Broegger Kristensen, M.; Wittrup Hansen, M. [Solum Gruppen, Hedehusene (Denmark); Uellendahl, H. [Aalborg Univ. (AAU), Aalborg (Denmark)

    2013-07-15

    This final project report contains a summary of the findings and documentation which have been carried out as a part of the EUDP-supported project ''Documentation and En-ergy Yield Optimisation of AIKAN{sup }- a dry anaerobic digestion biogas technology''. The aim was to improve documentation of the AIKAN{sup }technology, improve performance of the AIKAN{sup }technology and thus remove important barriers for market entry on principal export markets caused by the lack of performance documentation. The final report also contains a description of the subsequent process and technology improvements which have been carried out in order to improve and optimize the production process at the full scale AIKAN{sup }biogas plant, Biovaekst, in Audebo, Denmark. The relevant analyses carried out as part of the different work packages are attached as appendixes to the report. It is the intention that the final report and the attached appendices should function as a work of reference for the employees involved in the day to day running and optimization of the AIKAN{sup }technology. (Author)

  14. Anaerobic α-Amylase Production and Secretion with Fumarate as the Final Electron Acceptor in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Liu, Zihe; Österlund, Tobias; Hou, Jin;

    2013-01-01

    reticulum are transferred to fumarate as the final electron acceptor. This model is supported by findings that the addition of fumarate under anaerobic (but not aerobic) conditions improves cell growth, specifically in the α-amylase-producing strain, in which it is not used as a carbon source. Our results...

  15. Effect of carbon monoxide, hydrogen and sulfate on thermophilic (55 degrees C) hydrogenogenic carbon monoxide conversion in two anaerobic bioreactor sludges.

    Science.gov (United States)

    Sipma, J; Meulepas, R J W; Parshina, S N; Stams, A J M; Lettinga, G; Lens, P N L

    2004-04-01

    The conversion routes of carbon monoxide (CO) at 55 degrees C by full-scale grown anaerobic sludges treating paper mill and distillery wastewater were elucidated. Inhibition experiments with 2-bromoethanesulfonate (BES) and vancomycin showed that CO conversion was performed by a hydrogenogenic population and that its products, i.e. hydrogen and CO2, were subsequently used by methanogens, homo-acetogens or sulfate reducers depending on the sludge source and inhibitors supplied. Direct methanogenic CO conversion occurred only at low CO concentrations [partial pressure of CO (PCO) hydrogen production from CO, especially since after 30 min exposure to 95 degrees C, the production of CH4 at 55 degrees C was negligible. The paper mill sludge was capable of sulfate reduction with hydrogen, tolerating and using high CO concentrations (PCO>1.6 bar), indicating that CO-rich synthesis gas can be used efficiently as an electron donor for biological sulfate reduction.

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

    NARCIS (Netherlands)

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

    2004-01-01

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

  17. 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...

  18. 嗜热厌氧纤维素分解菌的分离、鉴定及其酶学特性%Isolation, identification and enzyme characterization of a thermophilic cellulolytic anaerobic bacterium

    Institute of Scientific and Technical Information of China (English)

    赵银瓶; 马诗淳; 孙颖杰; 黄艳; 邓宇

    2012-01-01

    [目的]分离高效降解纤维素的嗜热厌氧菌,通过与嗜热产乙醇菌株联合培养的方式,为生产纤维素乙醇提供微生物资源.[方法]利用厌氧分离技术从降解纤维素的马粪富集物中分离到一株嗜热厌氧细菌HCp.采用形态学观察、生理生化鉴定、结合16S rDNA序列的系统发育学分析确定该菌株的分类地位,利用DNS酶活分析方法测定此分离菌株的酶学性质.[结果]分离菌株HCp革兰氏染色阴性,直杆,细胞单个或成对出现,菌体大小为(0.35 -0.50) μm×(2.42 -6.40) μm,严格厌氧,形成芽胞,能运动,对新霉素有一定的抗性.此菌能利用滤纸纤维素、纤维素粉、微晶纤维素、脱脂棉和水稻秸秆、明胶等,还可以利用葡萄糖、纤维二糖、木糖、木聚糖、果糖、蔗糖、核糖、半乳糖、麦芽糖、山梨糖、海藻糖、蜜二糖、甘露糖等.该菌株在pH6.5 -8.5、温度35 - 70℃、盐浓度0% - 1.0%范围内利用纤维素生长,最适pH为6.85,最适温度为60℃,最适NaCl浓度为0.2%,最佳生长条件下,在10 d内滤纸纤维素降解率可达90.40%.在HCp的纤维小体中,滤纸酶、羧甲基纤维素酶、β-葡萄糖苷酶、木聚糖酶的最适作用温度分别为70℃、70℃、70℃、60℃,并且羧甲基纤维素酶具有较高的热稳定性.部分长度的16S rDNA序列分析表明,分离菌株HCp与Acetivibrio cellulolyticus、A.cellulosolvens相似性为97.5%.[结论]分离菌株HCp是从马粪富集物中分离到的一株嗜热厌氧细菌,该菌具有较强的降解纤维素能力,生长温度范围广,酶的热稳定性好,纤维素底物利用广泛等特性,为纤维素降解产乙醇提供了良好的材料.%[Objective ] To identify a thermophilic bacterium from horse manure to degrade cellulose efficiently, and to enrich microbial resources producing cellulolytic ethanol by co-culturing with thermophilic ethanol producing bacterium. [Methods] We used Hungate anaerobic

  19. Impact of pH Management Interval on Biohydrogen Production from Organic Fraction of Municipal Solid Wastes by Mesophilic Thermophilic Anaerobic Codigestion.

    Science.gov (United States)

    Arslan, Chaudhry; Sattar, Asma; Changying, Ji; Nasir, Abdul; Mari, Irshad Ali; Bakht, Muhammad Zia

    2015-01-01

    The biohydrogen productions from the organic fraction of municipal solid wastes (OFMSW) were studied under pH management intervals of 12 h (PM12) and 24 h (PM24) for temperature of 37 ± 0.1°C and 55 ± 0.1°C. The OFMSW or food waste (FW) along with its two components, noodle waste (NW) and rice waste (RW), was codigested with sludge to estimate the potential of biohydrogen production. The biohydrogen production was higher in all reactors under PM12 as compared to PM24. The drop in pH from 7 to 5.3 was observed to be appropriate for biohydrogen production via mesophilic codigestion of noodle waste with the highest biohydrogen yield of 145.93 mL/g CODremoved under PM12. When the temperature was increased from 37°C to 55°C and pH management interval was reduced from 24 h to 12 h, the biohydrogen yields were also changed from 39.21 mL/g COD removed to 89.67 mL/g COD removed, 91.77 mL/g COD removed to 145.93 mL/g COD removed, and 15.36 mL/g COD removed to 117.62 mL/g COD removed for FW, NW, and RW, respectively. The drop in pH and VFA production was better controlled under PM12 as compared to PM24. Overall, PM12 was found to be an effective mean for biohydrogen production through anaerobic digestion of food waste.

  20. Impact of pH Management Interval on Biohydrogen Production from Organic Fraction of Municipal Solid Wastes by Mesophilic Thermophilic Anaerobic Codigestion

    Directory of Open Access Journals (Sweden)

    Chaudhry Arslan

    2015-01-01

    Full Text Available The biohydrogen productions from the organic fraction of municipal solid wastes (OFMSW were studied under pH management intervals of 12 h (PM12 and 24 h (PM24 for temperature of 37±0.1°C and 55±0.1°C. The OFMSW or food waste (FW along with its two components, noodle waste (NW and rice waste (RW, was codigested with sludge to estimate the potential of biohydrogen production. The biohydrogen production was higher in all reactors under PM12 as compared to PM24. The drop in pH from 7 to 5.3 was observed to be appropriate for biohydrogen production via mesophilic codigestion of noodle waste with the highest biohydrogen yield of 145.93 mL/g CODremoved under PM12. When the temperature was increased from 37°C to 55°C and pH management interval was reduced from 24 h to 12 h, the biohydrogen yields were also changed from 39.21 mL/g CODremoved to 89.67 mL/g CODremoved, 91.77 mL/g CODremoved to 145.93 mL/g CODremoved, and 15.36 mL/g CODremoved to 117.62 mL/g CODremoved for FW, NW, and RW, respectively. The drop in pH and VFA production was better controlled under PM12 as compared to PM24. Overall, PM12 was found to be an effective mean for biohydrogen production through anaerobic digestion of food waste.

  1. A thermophilic microbial fuel cell design

    Science.gov (United States)

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

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

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

    OpenAIRE

    2006-01-01

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

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

    DEFF Research Database (Denmark)

    Chang, Tinghong; Yao, Shuo

    2011-01-01

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

  4. Comparison and Selection Analysis of Heating System of Mesophilic and Thermophilic Anaerobic Fermentation by Ground-source Heat Pump%地源热泵式中、高温厌氧发酵加温系统比选分析

    Institute of Scientific and Technical Information of China (English)

    吕涛; 石惠娴; 朱洪光; 徐凯; 范旻; 马洁琼

    2013-01-01

    [目的]筛选沼气工程发酵系统.[方法]比较70 m3/d日产气量的中型沼气工程用的地源热泵式中温厌氧发酵加温系统(池容产气率1 m3/(m3· d))和地源热泵式高温厌氧发酵加温系统(池容产气率2.2 m3/(m3· d))2种加温方案,计算其沼气池理论加温负荷、系统初投资以及运行费用,并分析了2者的技术可行性和经济效益.[结果]高温厌氧发酵系统的初投资比中温厌氧发酵系统少8.3万元,年运行费用少2 711元,投资效益净现值为123 333元.[结论]分析表明在加温系统的生命周期内,高温厌氧发酵系统具有更好的投资效益.%[Objective] To screen biogas project fermentation system.[Method] Heating system of mesophilic (biogas productivity at 1 m3/(m3 · d) and thermophilic (biogas productivity at 2.2 m3/(m3 · d) anaerobic fermentation by ground-source heat pump were compared,based on 70 m3/d daily biogas production of medium-sized biogas projects.Theoretical heating load of fermentation tank,initial investment and operating costs were calculated,and the economic benefits and technical feasibility were analyzed.[Result] The initial investment of thermophilic fermentation is lower than that of mesophilic fermentation by 83 000 yuan and annual operating costs of the heat pump is lower than that of mesophilic fermentation by 2 711 yuan.Investment returns net present value of thermophilic anaerobic fermentation system is 123 333 yuan.[Conclusion] Thermophilic fermentation system has a better investment returns in the life cycle of the heating system.

  5. Comparison of long-term performances and final microbial compositions of anaerobic reactors treating landfill leachate

    NARCIS (Netherlands)

    Calli, B.; Mertoglu, B.; Roest, C.; Inanc, B.

    2006-01-01

    Laboratory scale anaerobic upflow filter, sludge blanket and hybrid bed reactors were operated for 860 days in the treatment of high ammonia landfill leachate. Organic loading was gradually increased from 1.3 to 23.5 kg COD/m3 day in the start-up period and then fluctuated according to the COD conce

  6. Properties of thermophilic microorganisms

    International Nuclear Information System (INIS)

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

  7. Isolation, identification and metabolic characterization of an anaerobic thermophilic bacterium%一嗜热厌氧杆菌的分离、鉴定及其代谢特征

    Institute of Scientific and Technical Information of China (English)

    兰贵红; 葛菊; 刘海昌; 唐全武; 张辉; 乔代容; 曹毅

    2012-01-01

    [Objective] To isolate, protect thermophilic microbial resources from petroleum reservoirs and analyze these main metabolic characterization. [Methods] The strain BF1 was isolated by Hungte anaerobic technique from Chenghai 1 Unit of Dagang oil field in China. Its taxonomic status determined by physiological, biochemical and 16S Rrna gene sequence analysis. Its effect of sulfur metabolism on the corrosion current was measured by electrochemical analysis. [Results] The strain BF1 was Gram-negative, strictly thermophilic anaerobic, top-sporulating, non-motile, rods, 0.42 μmx(l.6-5.4) μm, grew solitary, in pairs or in chains. Growth occurred at 45 °C-75 °C (optimum 60 °C), at Ph 4.5-8.5 (optimum 6.5). Specific growth rate (μm) was 0.99 h-1 and doubling time was 42 min. Substrates included glucose, melizitose, raffinose, mannose, lactose, fructose and ribose. The main products of glucose fermentation were CO2, H2, acetate and ethanol. The strain could reduce thiosulfate and sulfite to sulfide, and its tolerance limits were 75 mmol/L and 50 mmol/L, respectively. The electrochemical impedance reduced from 2 099 Ω/cm2 to 776 Ω/cm2 and the corrosion current increased from 9.936e-006 A to 3.25e-005 A after thiosulfate (50 mmol/L) was reduced. The fatty acids were mainly composed of saturated long chain fatty acids, with C15:0 the most, accounting for 70.6%. The G+C content of DNA was 34.0 mol%. The 16S Rrna gene sequence analysis indicated that the closest phylogenetic relatives were Thermoanaerobacter pseudethanolicus DSM2355T and T. Brockii subsp. Brockii DSM1457T, 98.3% and 98.0%, respectively. However, the strain BF1 was different with T. Pseudethanolicus DSM2355T and T. Brockii subsp. Brockii DSM1457T in doubling time, optimum temperature and substrates utilized, and different with T. Pseudethanolicus DSM 2355T in fatty acid profile. [Conclusion] The strain BF1 may be a new species of Thermoanaerobacter genus, the exact taxonomic status of it requires DNA

  8. Physiologically anaerobic microorganisms of the deep subsurface. Final performance report, June 1, 1990--August 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, S.E. Jr.; Chung, K.T.

    1993-10-01

    Anaerobic bacteria were isolated from deep subsurface sediment samples taken at study sites in Idaho (INEL) and Washington (HR) by culturing on dilute and concentrated medium. Morphologically distinct colonies were purified, and their responses to 21 selected physiological tests were determined. Although the number of isolates was small (18 INEL, 27 HR) some general patterns could be determined. Most strains could utilize all the carbon sources, however the glycerol and melizitose utilization was positive for 50% or less of the HR isolates. Catalase activity (27.78% at INEL, 74.07% at HR) and tryptophan metabolism (11.12% at INEL, 40.74% at HR) were significantly different between the two study sites. MPN and viable counts indicate that sediments near the water table yield the greatest numbers of anaerobes. Deeper sediments also appear to be more selective with the greatest number of viable counts on low-nutrient mediums. Likewise, only strictly obligate anaerobes were found in the deepest sediment samples. Selective media indicated the presence of methanogens, acetogens, and sulfate reducers at only the HR site.

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

    NARCIS (Netherlands)

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

    2003-01-01

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

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

    NARCIS (Netherlands)

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

    2003-01-01

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

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

    Science.gov (United States)

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

    2015-09-01

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

  12. Anaerobic biprocessing of low rank coals. Final technical report, September 12, 1990--August 10, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Jain, M.K.; Narayan, R.

    1993-08-05

    Coal solubilization under aerobic conditions results in oxygenated coal product which, in turn, makes the coal poorer fuel than the starting material. A novel approach has been made in this project is to remove oxygen from coal by reductive decarboxylation. In Wyodak subbituminous coal the major oxygen functionality is carboxylic groups which exist predominantly as carboxylate anions strongly chelating metal cations like Ca{sup 2+} and forming strong macromolecular crosslinks which contribute in large measure to network polymer structure. Removal of the carboxylic groups at ambient temperature by anaerobic organisms would unravel the macromoleculer network, resulting in smaller coal macromolecules with increased H/C ratio which has better fuel value and better processing prospects. These studies described here sought to find biological methods to remove carboxylic functionalities from low rank coals under ambient conditions and to assess the properties of these modified coals towards coal liquefaction. Efforts were made to establish anaerobic microbial consortia having decarboxylating ability, decarboxylate coal with the adapted microbial consortia, isolate the organisms, and characterize the biotreated coal products. Production of CO{sup 2} was used as the primary indicator for possible coal decarboxylation.

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

    Science.gov (United States)

    Luo, Gang; Angelidaki, Irini

    2012-11-01

    Biogas produced by anaerobic digestion, is mainly used in a gas motor for heat and electricity production. However, after removal of CO(2) , biogas can be upgraded to natural gas quality, giving more utilization possibilities, such as utilization as autogas, or distant utilization by using the existing natural gas grid. The current study presents a new biological method for biogas upgrading in a separate biogas reactor, containing enriched hydrogenotrophic methanogens and fed with biogas and hydrogen. Both mesophilic- and thermophilic anaerobic cultures were enriched to convert CO(2) to CH(4) by addition of H(2) . Enrichment at thermophilic temperature (55°C) resulted in CO(2) and H(2) bioconversion rate of 320 mL CH(4) /(gVSS h), which was more than 60% higher than that under mesophilic temperature (37°C). Different dominant species were found at mesophilic- and thermophilic-enriched cultures, as revealed by PCR-DGGE. Nonetheless, they all belonged to the order Methanobacteriales, which can mediate hydrogenotrophic methanogenesis. Biogas upgrading was then tested in a thermophilic anaerobic reactor under various operation conditions. By continuous addition of hydrogen in the biogas reactor, high degree of biogas upgrading was achieved. The produced biogas had a CH(4) content, around 95% at steady-state, at gas (mixture of biogas and hydrogen) injection rate of 6 L/(L day). The increase of gas injection rate to 12 L/(L day) resulted in the decrease of CH(4) content to around 90%. Further study showed that by decreasing the gas-liquid mass transfer by increasing the stirring speed of the mixture the CH(4) content was increased to around 95%. Finally, the CH(4) content around 90% was achieved in this study with the gas injection rate as high as 24 L/(L day).

  14. 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...

  15. Research on the Nature of Thermophilic Anaerobic Ethanol Producer Thermo anaerobacter sp DF3 in Petroleum Reservoirs%一株产乙醇嗜热厌氧油藏微生物ThermoanaerobacterspDF3的性质研究

    Institute of Scientific and Technical Information of China (English)

    兰贵红; 邢钰; 曹毅; 乔代蓉; 邹长军; 邓宇; 张辉; 尹小波

    2012-01-01

    [目的]了解油藏微生物ThermoanaerobacterspDF3的生理生化特性,优化木糖产乙醇培养方案。[方法]利用厌氧分离技术从大港油田油层采出液中分离到一株产乙醇厌氧杆菌DF3采用生理生化鉴定与16SrDNA序列的系统发育学分析其系统发育地位,用气相色谱分析其代谢产物。[结果]菌株DF3是一株严格厌氧的嗜热细菌,呈直杆状,G-菌体大小为O.42μm×(1.60~5.20)μm,单生成对或成串生,产顶端芽孢;生长温度为45~78℃(最适65℃),能利用葡萄糖、木糖、果糖、核糖、甘露糖、阿拉伯糖、蔗糖、半乳糖、乳糖、纤维二糖、松三糖、棉子糖、淀粉等作为底物;其16SrRNA与zpseud。ethanolicw相似性为99.7%发酵葡萄糖与木糖的主要产物为乙醇,培养方案优化后其代谢木糖产乙醇终浓度为2.0g/L。[结论]通过试验证明菌株DF3是目前已知菌株中产乙醇活性较强的菌株之一,在65℃时代谢木糖能产生2.0g/L的乙醇目前代谢木糖高产乙醇的菌株均由国外分离获得,菌株DF3的分离获得为我国研究木质纤维素产乙醇提供了优良的出发菌株。%[Objective] The aim was to study the physiological and biochemical char- acteristics of Thermoanaerobacter sp DF3 in petroleum reservoirs and optimize the culture plan of producing ethanol from xylose. [Method] DF3, an anaerobic bacillus producing ethanol, was isolated from produced liquid from oil layer of Dagang oil field with anaerobic isolation technique. The phylogenetic position was analyzed by physiological and biochemical identification and phylogeny of 16S rDNA sequence. The metabolites were analyzed by gas chromatograph. [Result] The strain DF3 was a strict anaerobic thermophilic bacterium, which was straight in rod shape,and gram negative. Besides, it was 0.42 μmx(1.60-5.20) iJm in length. The strains can be soli- tary,in pairs or string and apical spore usually

  16. Comparative Studies of Alternative Anaerobic Digestion Technologies

    OpenAIRE

    Inman, David C.

    2004-01-01

    Washington D.C. Water and Sewage Authority is planning to construct a new anaerobic digestion facility at its Blue Plains WWTP by 2008. The research conducted in this study is to aid the designers of this facility by evaluating alternative digestion technologies. Alternative anaerobic digestion technologies include thermophilic, acid/gas phased, and temperature phased digestion. In order to evaluate the relative merits of each, a year long study evaluated the performance of bench scale dig...

  17. Anaerobes beyond anaerobic digestion

    OpenAIRE

    Sousa, D. Z.; Pereira, M A; Alves, M.M.

    2009-01-01

    Anaerobic microorganisms are widespread in nature. Sediments, gastrointestinal tracks, volcanic vents, geothermal sources are examples of habitats where anaerobic metabolism prevail, in some cases at extreme temperature, pH and pressure conditions. In such microbial ecosystems waste of some is food for others in a true integrated structure. Anaerobic microorganisms are able to use a wide variety of organic and inorganic compounds. Recalcitrant compounds, such as hydrocarbons, a...

  18. Thermophilic microorganisms in biomining.

    Science.gov (United States)

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

    2016-11-01

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

  19. Aplicação conjunta de tratamento anaeróbio termofílico por lodo granular e de mediadores redox na remoção de cor de águas residuárias têxteis Applicability of both thermophilic treatment by anaerobic granular sludge and redox mediators on colour removal of textile wastewaters

    Directory of Open Access Journals (Sweden)

    André Bezerra dos Santos

    2005-09-01

    Full Text Available Investigou-se o efeito de diferentes mediadores redox na remoção de cor de corantes azo pelo uso de lodo granular anaeróbio sob condições mesofílicas (30ºC e termofílicas (55ºC. Adicionalmente, estudou-se em ambas temperaturas, o efeito de diferentes doadores de elétrons nos processos de descoloração. Comprovou-se em tais processos um impacto marcante da adição de concentrações catalíticas de mediadores redox, aumentando a cinética da reação em até 1 ordem de magnitude. Comparado com tratamento mesofílico, remoções de cor sob condições termofílicas foram extremamente aceleradas, além de o impacto dos mediadores redox ser consideravelmente diminuído à 55ºC. Por exemplo, em experimento de fluxo contínuo, eficiências de remoção em torno de 95% e 56% foram obtidas à 55ºC e 30ºC, respectivamente, na ausência de qualquer mediador redox. Hidrogênio se mostrou extremamente efetivo como doador de elétrons para o processo de descoloração redutiva de corantes azo quando comparado com glicose, formiato e acetato. Os resultados obtidos nesta investigação trazem boas perspectivas para o uso conjunto de reatores anaeróbios sob condições termofílicas e de mediadores redox no pré-tratamento das águas residuárias de indústrias têxteis.The use of different redox mediators on colour removal of azo dyes by anaerobic granular sludge was investigated under mesophilic (30ºC and thermophilic (55ºC conditions. Additionally, the use of different electron donors on the reductive decolourisation was studied in both temperatures. The addition of catalytic concentrations of redox mediators had an evident impact on the decolourisation process, enhancing the rates up to one order of magnitude. Compared to mesophilic conditions, colour removal under thermophilic conditions was extremely accelerated, and the impact of redox mediators on the decolourisation rates was considerably decreased at 55ºC. For instance, in a

  20. Investigations on the inactivation of selected bacteria and viruses during mesophilic and thermophilic anaerobic alkaline cofermentation of biological waste materials, food residues and other animal residues; Seuchenhygienische Untersuchungen zur Inaktivierung ausgewaehlter Bakterien und Viren bei der mesophilen und thermophilen anaeroben alkalischen Faulung von Bio- und Kuechenabfaellen sowie anderen Rest- und Abfallstoffen tierischer Herkunft

    Energy Technology Data Exchange (ETDEWEB)

    Hoferer, M. [Hohenheim Univ., Stuttgart (Germany). Inst. fuer Umwelt- und Tierhygiene sowie Tiermedizin mit Tierklinik

    2001-07-01

    The purpose of this study is to investigate the inactivation kinetics of a number of different bacteria (Salmonella Senftenberg, Escherichia coli O157, Enterococcus faecium) and viruses (Bovine Enterovirus (ECBO), Equine Rhinovirus (ERV), Poliovirus, Bovine Parvovirus (BPV)) during the process of anaerobic cofermentation. Experiments were conducted in a semi-technical biogas plant at the University of Hohenheim. The fermenter was fed with a mixture of slurry from pigs or cattle (75%) and leftovers (25%) and was run under mesophilic (30 C + 35 C) as well as under thermophilic temperature conditions (50 C + 55 C). Volume and filter-sandwich germ-carriers were specifically developed and/or optimised for these analyses. Parallel to the experiments at the University of Hohenheim and under almost identical process conditions, various viruses (African Swine Fever Virus, Pseudorabies Virus, Classical Swine Fever Virus, Foot and Mouth Disease Virus, Swine Vesicular Disease Virus) were examined at the Federal Research Centre for Virus Diseases of Animals in Tuebingen. The results obtained at each research institution are directly compared. (orig.)

  1. Biodegradation of poly(lactic acid), poly(hydroxybutyrate-co-hydroxyvalerate), poly(butylene succinate) and poly(butylene adipate-co-terephthalate) under anaerobic and oxygen limited thermophilic conditions

    OpenAIRE

    Jutakan Boonmee; Charnwit Kositanont; Thanawadee Leejarkpai

    2016-01-01

    In order to study the biodegradation behavior of biodegradable plastics in landfill conditions, four types of biodegradable plastics including poly(lactic acid) (PLA), poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV), poly(butylene succinate) (PBS), and poly(butylene adipate-co-terephthalate) (PBAT) were tested by burying in sludge mixed soil medium under anaerobic and oxygen limited conditions. The experiments were operated at 52 ± 2ºC in dark conditions according to ISO15985. The degree of b...

  2. Biodegradation of poly(lactic acid, poly(hydroxybutyrate-co-hydroxyvalerate, poly(butylene succinate and poly(butylene adipate-co-terephthalate under anaerobic and oxygen limited thermophilic conditions

    Directory of Open Access Journals (Sweden)

    Jutakan Boonmee

    2016-01-01

    Full Text Available In order to study the biodegradation behavior of biodegradable plastics in landfill conditions, four types of biodegradable plastics including poly(lactic acid (PLA, poly(hydroxybutyrate-co-hydroxyvalerate (PHBV, poly(butylene succinate (PBS, and poly(butylene adipate-co-terephthalate (PBAT were tested by burying in sludge mixed soil medium under anaerobic and oxygen limited conditions. The experiments were operated at 52 ± 2ºC in dark conditions according to ISO15985. The degree of biodegradation after 75 days was investigated by weight loss determination, visual examination, and surface appearance by scanning electronic microscopy (SEM. Under both anaerobic and oxygen limited conditions, the complete degradation (100% weight loss was found only in PHBV after 75 days. The plastic degradations were ranked in the order of PHBV> PLA> PBS> PBAT. The percentage of weight losses were significantly different at p ≤ 0.05. However, for all studied plastics, the degradation under anaerobic and oxygen limited conditions did not significantly different at 95% confidence.

  3. A Hybrid System of Thermophillic Anaerobic Digestion and Heat Pump for Sludge Stabilization and Cascade Utilization of Energy in Municipal Sewage Treatment Plant%基于污水源热泵的污泥高温厌氧消化系统实验研究

    Institute of Scientific and Technical Information of China (English)

    田磊; 史琳; 吴静; 赵鹏娟; 施汉昌

    2011-01-01

    将污水源热泵应用到污泥高温厌氧消化流程,搭建了一套可同时实现污水热能资源化、污泥化学能资源化的实验系统.实验系统中,污水源热泵以污水处理厂二级出水为热源回收其中废热,所产出60℃-70℃中温热能供给热需求约为50℃的污泥高温厌氧消化工艺;高温厌氧消化工艺可快速、有效去除污泥中有机污染物,并产出清洁型能源沼气,而沼气可进一步用于污水处理工艺.实验系统设计了配备板式换热器的间接式污水源热泵系统、加热与维温分立的分块化污泥供热系统,提出了与污泥高温厌氧消化反应需热特性相匹配的热泵分段变工况控制策略.结果显示污水源热泵在供热水温50℃-70℃区间内稳定工作,可为高温厌氧消化提供连续、稳定热环境;供热系统负荷分配均匀,可保持高温厌氧反应器内±1℃温差;污泥水力停留时间5.5d时,挥发性悬浮固体降解率为52.2%,产气率平均为12.4m3/m3污泥(96%含水率).同时进一步利用实测数据分析了二级出水水温及水质对系统运行效率及稳定性的影响.%Municipal sewage treatment plants combine sewage and sludge together. Both of which sewage and sludge can be useful resources. A pilot system was bulit by using a moderately-high temperature sewage source heat pump to thermophilic anaerobic sludge digestion at a municipal sewage treatment plant in Southern China, with the aim to simultaneously provide stabilize sludge and reuse water with the recovery of chemical energy in sludge and thermal energy in sewage simultaneously. By using secondary effluent as the heat source, the heat pump canproduce moderately-high grade thermal energy (60℃-70℃ supply the heating needed ( at about 50℃) for the thermophilic anaerobic digestion. The system was designed by using an indirect-type sewage source heat pump and a fast-adjusting sludge heating system. The results show that the

  4. 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...

  5. Anaerobic fermentation of beef cattle manure

    Science.gov (United States)

    Hashimoto, A. G.; Chen, Y. R.; Varel, V. H.

    1981-01-01

    The conversion of livestock manure and crop residues into methane and a high protein feed ingredient by thermophilic anaerobic fermentation is summarized. The major biological and operational factors involved in methanogenesis are discussed, and a kinetic model that describes the fermentation process is presented. Substrate biodegradability, fermentation temperature, and influent substrate concentration to have significant effects on CH4 production rate. Assessment of the energy requirements for anaerobic fermentation systems showed that the major energy requirement for a thermophilic system was for maintaining the fermenter temperature. The next major energy consumption was due to the mixing of the influent slurry and fermenter liquor. An approach to optimizing anaerobic fermenter s by selecting design criteria that maximize the net energy production per unit cost is presented.

  6. Biochemistry and physiology of anaerobic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-05-18

    We welcome you to The Power of Anaerobes. This conference serves two purposes. One is to celebrate the life of Harry D. Peck, Jr.,who was born May 18, 1927 and would have celebrated his 73rd birthday at this conference. He died November 20, 1998. The second is to gather investigators to exchange views within the realm of anaerobic microbiology, an area in which tremendous progress has been seen during recent years. It is sufficient to mention discoveries of a new form of life (the archaea), hyper or extreme thermophiles, thermophilic alkaliphiles and anaerobic fungi. With these discoveries has come a new realization about physiological and metabolic properties of microorganisms, and this in turn has demonstrated their importance for the development, maintenance and sustenance of life on Earth.

  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. Biohydrogen Production by the Thermophilic Bacterium Caldicellulosiruptor saccharolyticus: Current Status and Perspectives

    NARCIS (Netherlands)

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

    2013-01-01

    Caldicellulosiruptor saccharolyticus is one of the most thermophilic cellulolytic organisms known to date. This Gram-positive anaerobic bacterium ferments a broad spectrum of mono-, di- and polysaccharides to mainly acetate, CO2 and hydrogen. With hydrogen yields approaching the theoretical limit fo

  9. Microbiology and physiology of anaerobic fermentation of cellulose. Annual report for 1990, 1992, 1993 and final report

    Energy Technology Data Exchange (ETDEWEB)

    Ljungdahl, L.G.; Wiegel, J.; Peck, H.D. Jr.; Mortenson, L.E.

    1993-08-31

    This report focuses on the bioconversion of cellulose to methane by various anaerobes. The structure and enzymatic activity of cellulosome and polycellulosome was studied in Clostridium thermocellum. The extracellular enzymes involved in the degradation of plant material and the physiology of fermentation was investigated in anaerobic fungi. Enzymes dealing with CO, CO{sub 2}, H{sub 2}, CH{sub 3}OH, as well as electron transport and energy generation coupled to the acetyl-CoA autotrophic pathway was studied in acetogenic clostridia.

  10. Methane enrichment digestion experiments at the anaerobic experimental test unit at Walt Disney World. Final report, March 1989-August 1990

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, V.J.; Hill, A.H.

    1993-06-01

    The goal of the project was to determine the technical feasibility of utilizing a novel concept in anaerobic digestion, in-situ methane enrichment digestion or MED for producing utility-grade gas from a pilot-scale anaerobic digester. MED tests conducted during this program consistently achieved digester product gas with a methane (CH4) content of greater than 90% (on a dry-, nitrogen-free basis). The MED concept, because it requires relatively simple equipment and modest energy input, has the potential to simplify gas cleanup requirements and substantially reduce the cost of converting wastes and biomass to pipeline quality gas.

  11. Lytic process studies on anaerobic digestion of organic wastes. Etude des activites lytiques intervenant au cours de la digestion anaerobie des dechets organiques; Rapport final

    Energy Technology Data Exchange (ETDEWEB)

    Durecu, S.; Thauront, J. (PEC Engineering, 95 - Cergy Pontoise (France). Service de Recherche et Developpement); Festino, C.; Aubart, C.; Reisinger, O. (Nancy-1 Univ., 54 - Vandoeuvre-les-Nancy (France). Lab. d' Ecologie Microbienne)

    1990-01-01

    To improve anaerobic digestion of pig manure, solubilization of the solid fraction was studied as the rate limiting step in the biomethanation process in an experimental completely mixed digester. The performance of conventional digesters should anaerobic microflora were inefficient in degrading complex biopolymers such as plant fibers. For pectin or cellulose, the use of digestible co-substrates accelerated methanation by increasing the yield of methane and a doubling of the apparent first order solubilization rate constant (Kp = 0.090/d). Lignin should methanation by decreasing methane yield and reducing the rate constant (Kp = 0.035/d). This inhibition was unrelated to volatile fatty acid accumulation. Nine strains of pectinolytic and/or cellulolytic bacteria were isolated. Chitin, a structural constituent of many final species, was effectively solubilized dining anaerobic digestion of pig manure. Seven strains of chitinolytic bacteria were isolated by high chitnese activity. The mycolytic power of fermenting manure processes acting through lytic microflora has been shown to be an effective antagonist of soil borne phytopathogenic fungi, as well as a fertilizer. In greenhouse trails, this compiled fraction demonstrated its ability to control flux unit. Keratin enhanced methane production, and increased H{sub 2}S nearly six-fold. Bacterial strains able to solubilize keratin were also used in autoclawed feather meal to extract the amino acids. (KJD)

  12. Final Report: Molecular mechanisms and kinetics of microbial anaerobic nitrate-dependent U(IV) and Fe(II) oxidation

    Energy Technology Data Exchange (ETDEWEB)

    O' Day, Peggy A. [Univ. of California, Merced, CA (United States); Asta, Maria P. [Univ. of California, Merced, CA (United States); Kanematsu, Masakazu [Univ. of California, Merced, CA (United States); Beller, Harry [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Zhou, Peng [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Steefel, Carl [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-02-27

    In this project, we combined molecular genetic, spectroscopic, and microscopic techniques with kinetic and reactive transport studies to describe and quantify biotic and abiotic mechanisms underlying anaerobic, nitrate-dependent U(IV) and Fe(II) oxidation, which influences the long-term efficacy of in situ reductive immobilization of uranium at DOE sites. In these studies, Thiobacillus denitrificans, an autotrophic bacterium that catalyzes anaerobic U(IV) and Fe(II) oxidation, was used to examine coupled oxidation-reduction processes under either biotic (enzymatic) or abiotic conditions in batch and column experiments with biogenically produced UIVO2(s). Synthesis and quantitative analysis of coupled chemical and transport processes were done with the reactive transport modeling code Crunchflow. Research focused on identifying the primary redox proteins that catalyze metal oxidation, environmental factors that influence protein expression, and molecular-scale geochemical factors that control the rates of biotic and abiotic oxidation.

  13. Report on the design and operation of a full-scale anaerobic dairy manure digester. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Coppinger, E.; Brautigam, J.; Lenart, J.; Baylon, D.

    1979-12-01

    A full-scale anaerobic digester on the Monroe State Dairy Farm was operated and monitored for 24 months with funding provided by the United States Department of Energy, Fuels from Biomass Systems Branch. During the period of operation, operating parameters were varied and the impact of those changes is described. Operational experiences and system component performance are discussed. Internal digester mixing equipment was found to be unnecessary, and data supporting this conclusion are given. An influent/effluent heat exchanger was installed and tested, and results of the tests are included. Recommendations for digester design and operation are presented. Biological stability was monitored, and test results are given. Gas production rates and system net energy are analyzed. The economics of anaerobic digestion are evaluated based on various financing options, design scales, and expected benefits. Under many circumstances digesters are feasible today, and a means of analysis is given.

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

    Science.gov (United States)

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

    2004-04-01

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

  15. Thermophilic molds: Biology and applications.

    Science.gov (United States)

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

    2016-11-01

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

  16. Microbiological Hydrogen Production by Anaerobic Fermentation and Photosynthetic Process

    Energy Technology Data Exchange (ETDEWEB)

    Asada, Y.; Ohsawa, M.; Nagai, Y.; Fukatsu, M.; Ishimi, K.; Ichi-ishi, S.

    2009-07-01

    Hydrogen gas is a clean and renewable energy carrier. Microbiological hydrogen production from glucose or starch by combination used of an anaerobic fermenter and a photosynthetic bacterium, Rhodobacter spheroides RV was studied. In 1984, the co-culture of Clostridium butyricum and RV strain to convert glucose to hydrogen was demonstrated by Miyake et al. Recently, we studied anaerobic fermentation of starch by a thermophilic archaea. (Author)

  17. Life Cycle Assessment of different uses of biogas from anaerobic digestion of separately collected biodegradable waste in France. Final report

    International Nuclear Information System (INIS)

    In the first part of the study, Gaz de France (GdF) and the French Environment Energy Management Agency (ADEME) wished to identify the best method to use the biogas from anaerobic digestion of separately collected biodegradable waste (bio-waste). Secondly, GdF and ADEME wished to evaluate the strength and weaknesses of the two main different organic recycling: anaerobic digestion (methanization) and composting. The study is based on the life cycle assessment method. The life cycle assessment used for this study consists in quantifying the environmental impacts of all of the activities which are related to the chosen use method. This methodology involves compiling a detailed account of all substances and energy flows removed or emitted from or into the environment at each stage of the life cycle. These flows are then translated into indicators of potential environment impacts. This methodology is based on the international standards ISO14040 and ISO 14044. The life cycle assessment was performed by RDC Environnement. In this study, two questions were treated: - Which is the best valorisation method for biogas produced from the anaerobic digestion of separately collected biodegradable waste: fuel, heat or electricity? ('Biogas' question); - Which is the best treatment for the separately collected biodegradable waste: anaerobic digestion (methanization) or industrial composting? ('Composting' question). The field of the study includes the arrival of the separately collected biodegradable waste at the anaerobic unit as well as the utilisation of the biogas energy and the agricultural use of the digestate from anaerobic digestion. For each biogas utilisation, the environmental impacts of each life cycle stage were considered as well as the impacts that were avoided due to the substitution of the use of non-renewable energy ('conventional' procedures). The modelling of the direct composting of the biodegradable waste was realised taking into account the followings

  18. Anaerobic degradation of linear alkylbenzene sulfonate

    DEFF Research Database (Denmark)

    Mogensen, Anders Skibsted; Haagensen, Frank; Ahring, Birgitte Kiær

    2003-01-01

    Linear alkylbenzene sulfonate (LAS) found in wastewater is removed in the wastewater treatment facilities by sorption and aerobic biodegradation. The anaerobic digestion of sewage sludge has not been shown to contribute to the removal. The concentration of LAS based on dry matter typically increa...... under thermophilic conditions was 37% with LAS as sole carbon source. Benzaldehyde was produced in the UASB reactor during LAS transformation....

  19. Inhibitory effects on anaerobic digestion of swine manure

    International Nuclear Information System (INIS)

    This paper presents a laboratory study using anaerobic digestion for swine manure under both mesophilic and thermophilic conditions, with emphasis on the effects of inhibitory chemicals on biogas production. A series of batch tests were conducted to examine the effects of various process parameters by varying temperature, pH, ammonia and hydrogen sulfide concentrations. As well, continuous anaerobic digestion tests were conducted using a completely stirred reactor system with a sludge retention time of 15 days. The results showed that at the initial stage, biogas was generated rapidly in the thermophilic reactor, but was more and more inhibited during the later stage with the presence of ammonia and hydrogen sulfide. In contrast, the biogas production was initially delayed in the mesophilic reactor but afterwards had an even higher total gas production. In order to take advantages of both temperature effects in each reactor, the dual-stage system that consists of a thermophilic reactor followed by a mesophilic reactor was suggested. (author)

  20. Enrichment of anaerobic syngas converting bacteria from bioreactor sludges

    NARCIS (Netherlands)

    Alves, J.I.; Stams, A.J.M.; Plugge, C.M.; Alves, M.M.; Sousa, D.Z.

    2013-01-01

    Thermophilic (55°C) anaerobic microbial communities were enriched with a synthetic syngas mixture (composed of CO, H2 and CO2 ) or with CO alone. Cultures T-Syn and T-CO were incubated and successively transferred with syngas (16 transfers) or CO (9 transfers), respectively, with increasing CO parti

  1. Effect of hydraulic retention time on sulfate reduction in a carbon monoxide fed thermophilic gas lift reactor

    NARCIS (Netherlands)

    Sipma, J.; Osuna, M.B.; Lettinga, G.; Stams, A.J.M.; Lens, P.N.L.

    2007-01-01

    Thermophilic hydrogenogenic carbon monoxide (CO) converting microorganisms present in anaerobic sludge play a crucial role in the application of CO as electron donor for sulfate reduction. Hydrogenogenic CO conversion was investigated in a gas lift reactor (55 °C) at different hydraulic retention ti

  2. Effects of triclosan, diclofenac, and nonylphenol on mesophilic and thermophilic methanogenic activity and on the methanogenic communities

    DEFF Research Database (Denmark)

    Symsaris, Evangelos C.; Fotidis, Ioannis; Stasinakis, Athanasios S.;

    2015-01-01

    In this study, a toxicity assay using a mesophilic wastewater treatment plant sludge-based (SI) and a thermophilic manure-based inoculum (MI), under different biomass concentrations was performed to define the effects of diclofenac (DCF), triclosan (TCS), and nonylphenol (NP) on anaerobic digestion...

  3. Methanogenesis in Thermophilic Biogas Reactors

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær

    1995-01-01

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

  4. Mechanism and Effect of Temperature on Variations in Antibiotic Resistance Genes during Anaerobic Digestion of Dairy Manure

    Science.gov (United States)

    Sun, Wei; Qian, Xun; Gu, Jie; Wang, Xiao-Juan; Duan, Man-Li

    2016-07-01

    Animal manure comprises an important reservoir for antibiotic resistance genes (ARGs), but the variation in ARGs during anaerobic digestion at various temperatures and its underlying mechanism remain unclear. Thus, we performed anaerobic digestion using dairy manure at three temperature levels (moderate: 20 °C, mesophilic: 35 °C, and thermophilic: 55 °C), to analyze the dynamics of ARGs and bacterial communities by quantitative PCR and 16S rRNA gene sequencing. We found that 8/10 detected ARGs declined and 5/10 decreased more than 1.0 log during thermophilic digestion, whereas only four and five ARGs decreased during moderate and mesophilic digestion, respectively. The changes in ARGs and bacterial communities were similar under the moderate and mesophilic treatments, but distinct from those in the thermophilic system. Potential pathogens such as Bacteroidetes, Proteobacteria, and Corynebacterium were removed by thermophilic digestion but not by moderate and mesophilic digestion. The bacterial community succession was the dominant mechanism that influenced the variation in ARGs and integrons during anaerobic digestion. Thermophilic digestion decreased the amount of mesophilic bacteria (Bacteroidetes and Proteobacteria) carrying ARGs. Anaerobic digestion generally decreased the abundance of integrons by eliminating the aerobic hosts of integrons (Actinomycetales and Bacilli). Thermophilic anaerobic digestion is recommended for the treatment and reuse of animal manure.

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

    DEFF Research Database (Denmark)

    Luo, Gang; Angelidaki, Irini

    2012-01-01

    by PCR–DGGE. Nonetheless, they all belonged to the order Methanobacteriales, which can mediate hydrogenotrophic methanogenesis. Biogas upgrading was then tested in a thermophilic anaerobic reactor under various operation conditions. By continuous addition of hydrogen in the biogas reactor, high degree...... the existing natural gas grid. The current study presents a new biological method for biogas upgrading in a separate biogas reactor, containing enriched hydrogenotrophic methanogens and fed with biogas and hydrogen. Both mesophilic- and thermophilic anaerobic cultures were enriched to convert CO2 to CH4...... by addition of H2. Enrichment at thermophilic temperature (55°C) resulted in CO2 and H2 bioconversion rate of 320 mL CH4/(gVSS h), which was more than 60% higher than that under mesophilic temperature (37°C). Different dominant species were found at mesophilic- and thermophilic-enriched cultures, as revealed...

  6. 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

  7. Microbial influenced corrosion by thermophilic bacteria

    Science.gov (United States)

    Lata, Suman; Sharma, Chhaya; Singh, Ajay

    2012-03-01

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

  8. Biohydrogen Production by the Thermophilic Bacterium Caldicellulosiruptor saccharolyticus: Current Status and Perspectives

    OpenAIRE

    Kengen, Servé W. M.; Verhaart, Marcel R. A.; John van der Oost; Abraham A. M. Bielen

    2013-01-01

    Caldicellulosiruptor saccharolyticus is one of the most thermophilic cellulolytic organisms known to date. This Gram-positive anaerobic bacterium ferments a broad spectrum of mono-, di- and polysaccharides to mainly acetate, CO2 and hydrogen. With hydrogen yields approaching the theoretical limit for dark fermentation of 4 mol hydrogen per mol hexose, this organism has proven itself to be an excellent candidate for biological hydrogen production. This review provides an overview of the resear...

  9. Biohydrogen Production by the Thermophilic Bacterium Caldicellulosiruptor saccharolyticus: Current Status and Perspectives.

    Science.gov (United States)

    Bielen, Abraham A M; Verhaart, Marcel R A; van der Oost, John; Kengen, Servé W M

    2013-01-17

    Caldicellulosiruptor saccharolyticus is one of the most thermophilic cellulolytic organisms known to date. This Gram-positive anaerobic bacterium ferments a broad spectrum of mono-, di- and polysaccharides to mainly acetate, CO2 and hydrogen. With hydrogen yields approaching the theoretical limit for dark fermentation of 4 mol hydrogen per mol hexose, this organism has proven itself to be an excellent candidate for biological hydrogen production. This review provides an overview of the research on C. saccharolyticus with respect to the hydrolytic capability, sugar metabolism, hydrogen formation, mechanisms involved in hydrogen inhibition, and the regulation of the redox and carbon metabolism. Analysis of currently available fermentation data reveal decreased hydrogen yields under non-ideal cultivation conditions, which are mainly associated with the accumulation of hydrogen in the liquid phase. Thermodynamic considerations concerning the reactions involved in hydrogen formation are discussed with respect to the dissolved hydrogen concentration. Novel cultivation data demonstrate the sensitivity of C. saccharolyticus to increased hydrogen levels regarding substrate load and nitrogen limitation. In addition, special attention is given to the rhamnose metabolism, which represents an unusual type of redox balancing. Finally, several approaches are suggested to improve biohydrogen production by C. saccharolyticus.

  10. Biohydrogen Production by the Thermophilic Bacterium Caldicellulosiruptor saccharolyticus: Current Status and Perspectives

    Directory of Open Access Journals (Sweden)

    Servé W. M. Kengen

    2013-01-01

    Full Text Available Caldicellulosiruptor saccharolyticus is one of the most thermophilic cellulolytic organisms known to date. This Gram-positive anaerobic bacterium ferments a broad spectrum of mono-, di- and polysaccharides to mainly acetate, CO2 and hydrogen. With hydrogen yields approaching the theoretical limit for dark fermentation of 4 mol hydrogen per mol hexose, this organism has proven itself to be an excellent candidate for biological hydrogen production. This review provides an overview of the research on C. saccharolyticus with respect to the hydrolytic capability, sugar metabolism, hydrogen formation, mechanisms involved in hydrogen inhibition, and the regulation of the redox and carbon metabolism. Analysis of currently available fermentation data reveal decreased hydrogen yields under non-ideal cultivation conditions, which are mainly associated with the accumulation of hydrogen in the liquid phase. Thermodynamic considerations concerning the reactions involved in hydrogen formation are discussed with respect to the dissolved hydrogen concentration. Novel cultivation data demonstrate the sensitivity of C. saccharolyticus to increased hydrogen levels regarding substrate load and nitrogen limitation. In addition, special attention is given to the rhamnose metabolism, which represents an unusual type of redox balancing. Finally, several approaches are suggested to improve biohydrogen production by C. saccharolyticus.

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

    NARCIS (Netherlands)

    Mashad, El H.

    2003-01-01

    Liquid and solid cattle manures are major waste streams inEgypt. The main objective of

  12. Parameter identification of thermophilic anaerobic degradation of valerate

    DEFF Research Database (Denmark)

    Flotats, X.; Ahring, Birgitte Kiær; Angelidaki, Irini

    2003-01-01

    identification was done optimizing the sum of the multiple determination coefficients for all measured state variables and for all experiments simultaneously. The estimated values of kinetic parameters and stoichiometric coefficients were characterized by the parameter correlation matrix, the confidence interval......The considered mathematical model of the decomposition of valerate presents three unknown kinetic parameters, two unknown stoichiometric coefficients, and three unknown initial concentrations for biomass. Applying a structural identifiability study, we concluded that it is necessary to perform...

  13. Parameter identification of thermophilic anaerobic degradation of valerate

    DEFF Research Database (Denmark)

    Flotats, X; Ahring, Birgitte Kiær; Angelidaki, Irini

    2002-01-01

    Mathematical model of the decomposition of valerate presents 3 unknown kinetic parameters, 2 unknown stoichiometric coefficients and 3 unknown initial concentrations for biomass. Applying a structural identifiability study, it is concluded that it is necessary to perform simultaneous batch experi...

  14. Production of Bioethanol From Lignocellulosic Biomass Using Thermophilic Anaerobic Bacteria

    DEFF Research Database (Denmark)

    Georgieva, Tania I.

    2006-01-01

    Bioethanol (ethanol produced from biomass) as a motor fuel is an attractive renewable fully sustainable energy sources as a means of lowering dependence on fossil fuels and air pollution towards greenhouse gasses, particularly CO2. Bioethanol, unlike gasoline, is an oxygenated fuel, which burns...... cleaner and thus lowers emissions of CO, NOx and unburned hydrocarbons pollutants, which are constituents in ground level ozone and particulate matter pollution (smog). In addition, bioethanol can replace currently used gasoline octane booster MTBE (methyl tertiary butyl ether), which causes serious...... are residual lignocellulose (wastes) created from forest industries or from agricultural food crops (wheat straw, corn stover, rice straw). The lignocellulose contains lignin, which binds carbohydrate polymers (cellulose and hemicellulose) forming together a rather resistant structure. In this regards, a pre...

  15. Thermophilic anaerobic acetate-utilizing methanogens and their metabolism

    DEFF Research Database (Denmark)

    Mladenovska, Zuzana

    , 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...

  16. Genomic characterization of Defluviitoga tunisiensis L3, a key hydrolytic bacterium in a thermophilic biogas plant and its abundance as determined by metagenome fragment recruitment.

    Science.gov (United States)

    Maus, Irena; Cibis, Katharina Gabriela; Bremges, Andreas; Stolze, Yvonne; Wibberg, Daniel; Tomazetto, Geizecler; Blom, Jochen; Sczyrba, Alexander; König, Helmut; Pühler, Alfred; Schlüter, Andreas

    2016-08-20

    The genome sequence of Defluviitoga tunisiensis L3 originating from a thermophilic biogas-production plant was established and recently published as Genome Announcement by our group. The circular chromosome of D. tunisiensis L3 has a size of 2,053,097bp and a mean GC content of 31.38%. To analyze the D. tunisiensis L3 genome sequence in more detail, a phylogenetic analysis of completely sequenced Thermotogae strains based on shared core genes was performed. It appeared that Petrotoga mobilis DSM 10674(T), originally isolated from a North Sea oil-production well, is the closest relative of D. tunisiensis L3. Comparative genome analyses of P. mobilis DSM 10674(T) and D. tunisiensis L3 showed moderate similarities regarding occurrence of orthologous genes. Both genomes share a common set of 1351 core genes. Reconstruction of metabolic pathways important for the biogas production process revealed that the D. tunisiensis L3 genome encodes a large set of genes predicted to facilitate utilization of a variety of complex polysaccharides including cellulose, chitin and xylan. Ethanol, acetate, hydrogen (H2) and carbon dioxide (CO2) were found as possible end-products of the fermentation process. The latter three metabolites are considered to represent substrates for methanogenic Archaea, the key organisms in the final step of the anaerobic digestion process. To determine the degree of relatedness between D. tunisiensis L3 and dominant biogas community members within the thermophilic biogas-production plant, metagenome sequences obtained from the corresponding microbial community were mapped onto the L3 genome sequence. This fragment recruitment revealed that the D. tunisiensis L3 genome is almost completely covered with metagenome sequences featuring high matching accuracy. This result indicates that strains highly related or even identical to the reference strain D. tunisiensis L3 play a dominant role within the community of the thermophilic biogas-production plant. PMID

  17. Ethanol production by engineered thermophiles.

    Science.gov (United States)

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

    2015-06-01

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

  18. Anaerobic digestion of slaughterhouse by-products

    DEFF Research Database (Denmark)

    Hejnfelt, Anette; Angelidaki, Irini

    2009-01-01

    hydrolysis (NaOH) had no effect on achieved methane yields. Mesophilic digestion was more stable than thermophilic digestion, and higher methane yield was noticed at high waste concentrations. The lower yield at thermophilic temperature and high waste concentration was due to ammonia inhibition. Co......Anaerobic digestion of animal by-products was investigated in batch and semi-continuously fed, reactor experiments at 55 degrees C and for some experiments also at 37 degrees C. Separate or mixed by-products from pigs were tested. The methane potential measured by batch assays for meat- and bone...... giving the best results. High concentrations of long-chain fatty acids and ammonia in the by-products were found to inhibit the biogas process at concentrations higher than 5 g lipids dm(-3) and 7 gN dm(-3) respectively. Pretreatment (pasteurization: 70 degrees C, sterilization: 133 degrees C, and alkali...

  19. Anaerobic co-digestion of sewage sludge. Application to the macroalgae from the Venice lagoon

    Energy Technology Data Exchange (ETDEWEB)

    Cecchi, F. [University of L`Aquila, Department of Chemistry, Chemical Engineering and Materials, Abruzzo (Italy); Pavan, P. [Environmental Sciences, University of Venice, Venice (Italy); Mata-Alvarez, J. [Department of Chemical Engineering, University of Barcelona, Barcelona (Spain)

    1996-07-05

    Possibilities of co-digestion of sewage sludge (SS) with other organic wastes are examined in this paper. Anaerobic co-digestion of macroalgae of the Venice lagoon (A) with SS, in wastewater treatment plants is studied in detail. This approach can contribute to the solution of the final disposal of the 50,000 m{sup 3} of macrophytes harvested each season. These are mainly Ulva rigida and Gracilaria confervoides. In the experiments A and SS were mixed at different ratios (20 - 40% algae, TS basis) and fed to mesophilic (37C) and thermophilic (55C) digesters which operated at 11- to 15-day hydraulic retention times and 1.7 - 4.4 kgTVS/ m{sup 3}/day organic loading rates. It was concluded that the mesophilic co-digestion process is applicable with potentialities of around 30% of the present SS flow-rate. Thermophilic digestion is not possible, because of the inhibition of methanogens probably due to the activity of sulphate-reducers

  20. Investigation of Poultry Waste for Anaerobic Digestion: A Case Study

    Science.gov (United States)

    Salam, Christopher R.

    Anaerobic Digestion (AD) is a biological conversion technology which is being used to produce bioenergy all over the world. This energy is created from biological feedstocks, and can often use waste products from various food and agricultural processors. Biogas from AD can be used as a fuel for heating or for co-generation of electricity and heat and is a renewable substitute to using fossil fuels. Nutrient recycling and waste reduction are additional benefits, creating a final product that can be used as a fertilizer in addition to energy benefits. This project was conducted to investigate the viability of three turkey production wastes as AD feedstock: two turkey litters and a material separated from the turkey processing wastewater using dissolved air flotation (DAF) process. The DAF waste contained greases, oils and other non-commodity portions of the turkey. Using a variety of different process methods, types of bacteria, loading rates and food-to-microorganism ratios, optimal loading rates for the digestion of these three materials were obtained. In addition, the co-digestion of these materials revealed additional energy benefits. In this study, batch digestion tests were carried out to treat these three feedstocks, using mesophilic and thermophilic bacteria, using loading rates of 3 and 6 gVS/L They were tested separately and also as a mixture for co-digestion. The batch reactor used in this study had total and working volumes of 1130 mL and 500 mL, respectively. The initial organic loading was set to be 3 gVS/L, and the food to microorganism ratio was either 0.6 or 1.0 for different treatments based on the characteristics of each material. Only thermophilic (50 +/- 2ºC) temperatures were tested for the litter and DAF wastes in continuous digestion, but mesophilic and thermophilic batch digestion experiments were conducted. The optimum digestion time for all experiments was 14 days. The biogas yields of top litter, mixed litter, and DAF waste under

  1. Anaerobic Process.

    Science.gov (United States)

    Yang, Qian; Ju, Mei-Ting; Li, Wei-Zun; Liu, Le; Wang, Yan-Nan; Chang, Chein-Chi

    2016-10-01

    A review of the literature published in 2015 on the focus of Anaerobic Process. It is divided into the following sections. Pretreatment Organic waste Multiple-stage co-digestion Process Methodology and Technology. PMID:27620085

  2. Anaerobic bacteria

    Science.gov (United States)

    Brook I, Goldstein EJ. Diseases caused by non-spore forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 297. Stedman's Online ...

  3. Anaerobic digestion of aliphatic polyesters.

    Science.gov (United States)

    Šmejkalová, Pavla; Kužníková, Veronika; Merna, Jan; Hermanová, Soňa

    2016-01-01

    Anaerobic processes for the treatment of plastic materials waste represent versatile and effective approach in environmental protection and solid waste management. In this work, anaerobic biodegradability of model aliphatic polyesters, poly(L-lactic acid) (PLA), and poly(ɛ-caprolactone) (PCL), in the form of powder and melt-pressed films with varying molar mass, was studied. Biogas production was explored in batch laboratory trials at 55 ± 1°C under a nitrogen atmosphere. The inoculum used was thermophilic digested sludge (total solids concentration of 2.9%) from operating digesters at the Central Waste Water Treatment Plant in Prague, Czech Republic. Methanogenic biodegradation of PCLs typically yielded from 54 to 60% of the theoretical biogas yield. The biodegradability of PLAs achieved from 56 to 84% of the theoretical value. High biogas yield (up to 677 mL/g TS) with high methane content (more than 60%), comparable with conventionally processed materials, confirmed the potential of polyester samples for anaerobic treatment in the case of their exploitation in agriculture or as a packaging material in the food industry. PMID:27191559

  4. 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)

  5. 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.

  6. Effect of COD/SO42- ratio and sulfide on thermophilic (55°C) sulfate reduction during the acidification of sucrose at pH 6

    NARCIS (Netherlands)

    Lopes, S.I.C.; Wang, X.; Capela, M.I.; Lens, P.N.L.

    2007-01-01

    This study investigated the effect of the COD/SO42¿ ratio (4 and 1) and the sulfide concentration on the performance of thermophilic (55 °C) acidifying (pH 6) upflow anaerobic sludge bed reactors fed with sucrose at an organic loading rate of 4.5 g COD lreactor¿1 day¿1. Sulfate reduction efficiencie

  7. Climatic change and health. Which problems are caused by thermophile hazardous organisms? Final report. Environment and health: climatic change; Klimawandel und Gesundheit. Welche Probleme verursachen Waerme liebende Schadorganismen? Abschlussbericht. Umwelt and Gesundheit: Klimawandel

    Energy Technology Data Exchange (ETDEWEB)

    Augustin, Jobst; Muecke, Hans-Guido (comps.)

    2010-03-15

    Climatic changes can cause health hazards due to thermophile harmful organisms, especially those with increased allergic potentials. The meeting covered the following topics: climatic change induced health hazards and the German adaptation strategies; the complex relation between climatic change and allergies; ambrosia propagation in Germany - hazards for health and biodiversity; climatic change induced reaction of hygienically precarious organism in urban regions; monitoring and abatement of Thaumetopoea processionea in Bavarian woods; climatic change and pollen flight dynamics; Thaumetopoea processionea as cause for non-distinctive respiratory systems diseases; risk and protection factors for the development of asthma and allergies during infancy; abatement of pathogenic or invasive harmful organisms in Switzerland; health hazards in connection with Thaumetopoea processionea - examples from Bavaria; retrospective analysis of EPS diseases during 2004 and 2005 in the region Kleve.

  8. Improvement of anaerobic digestion of sludge

    Energy Technology Data Exchange (ETDEWEB)

    Dohanyos, Michael; Zabranska, Jana; Kutil, Josef; Jenicek, Pavel

    2003-07-01

    Anaerobic digestion improvement can be accomplished by different methods. Besides optimization of process conditions is frequently used pretreatment of input sludge and increase of process temperature. Thermophilic process brings a higher solids reduction and biogas production, the high resistance to foaming, no problems with odour, the higher effect of destroying pathogens and the improvement of the energy balance of the whole treatment plant. Disintegration of excess activated sludge in lysate centrifuge was proved in full-scale conditions causing increase of biogas production. The rapid thermal conditioning of digested sludge is acceptable method of particulate matter disintegration and solubilization. (author)

  9. Digestion of cattle manure under mesophilic and thermophilic conditions: characterization of organic matter applying thermal analysis and 1H NMR.

    Science.gov (United States)

    Gómez, X; Blanco, D; Lobato, A; Calleja, A; Martínez-Núñez, F; Martin-Villacorta, J

    2011-06-01

    Digestion of cattle manure collected from a livestock farm together with bedding material (straw) has been studied under mesophilic and thermophilic conditions in batch reactors. The digestion was carried out for a prolonged period with the aim of evaluating the changes undergone by the organic matter. The mesophilic digestion carried out revealed a greater capacity to produce gas and transform organic matter, while a higher conversion rate, but a lower gas yield, was obtained under thermophilic conditions. Degradation of the organic matter was evaluated by means of thermal analysis and (1)H NMR. Stabilisation through anaerobic digestion (either mesophilic or thermophilic) resulted in an increase in the quality of the organic matter, as characterised by an enrichment in thermostable compounds, and an accumulation of long chain aliphatic materials. The experiments performed demonstrated the transformation of organic matter into complex materials under anaerobic conditions with an accumulation of aliphatic components under both types of conditions tested. Degradation through mesophilic digestion, in comparison to the thermophilic process, resulted in a greater destruction of straw particles. PMID:21082330

  10. Anaerobic Codigestion of Sludge: Addition of Butcher's Fat Waste as a Cosubstrate for Increasing Biogas Production.

    Science.gov (United States)

    Martínez, E J; Gil, M V; Fernandez, C; Rosas, J G; Gómez, X

    2016-01-01

    Fat waste discarded from butcheries was used as a cosubstrate in the anaerobic codigestion of sewage sludge (SS). The process was evaluated under mesophilic and thermophilic conditions. The codigestion was successfully attained despite some inhibitory stages initially present that had their origin in the accumulation of volatile fatty acids (VFA) and adsorption of long-chain fatty acids (LCFA). The addition of a fat waste improved digestion stability and increased biogas yields thanks to the higher organic loading rate (OLR) applied to the reactors. However, thermophilic digestion was characterized by an effluent of poor quality and high VFA content. Results from spectroscopic analysis suggested the adsorption of lipid components onto the anaerobic biomass, thus disturbing the complete degradation of substrate during the treatment. The formation of fatty aggregates in the thermophilic reactor prevented process failure by avoiding the exposure of biomass to the toxic effect of high LCFA concentrations. PMID:27071074

  11. A Model of Solar Energy Utilisation in the Anaerobic Digestion of Cattle Manure

    NARCIS (Netherlands)

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

    2003-01-01

    The anaerobic digestion of cow manure has a higher destruction of pathogens and weed seeds under thermophilic conditions compared to mesophilic conditions. To maintain such conditions, solar energy can be used. In this research, the consequences of the use of solar energy under Egyptian conditions a

  12. Evaluation of methods for preparing hydrogen-producing seed inocula under thermophilic condition by process performance and microbial community analysis.

    Science.gov (United States)

    O-Thong, Sompong; Prasertsan, Poonsuk; Birkeland, Nils-Kåre

    2009-01-01

    Five methods for preparation of hydrogen-producing seeds (base, acid, 2-bromoethanesulfonic acid (BESA), load-shock and heat shock treatments) as well as an untreated anaerobic digested sludge were compared for their hydrogen production performance and responsible microbial community structures under thermophilic condition (60 degrees C). The results showed that the load-shock treatment method was the best for enriching thermophilic hydrogen-producing seeds from mixed anaerobic cultures as it completely repressed methanogenic activity and gave the a maximum hydrogen production yield of 1.96 mol H(2) mol(-1) hexose with an hydrogen production rate of 11.2 mmol H(2) l(-1)h(-1). Load-shock and heat-shock treatments resulted in a dominance of Thermoanaerobacterium thermosaccharolyticum with acetic acid and butyric acid type of fermentation while base- and acid-treated seeds were dominated by Clostridium sp. and BESA-treated seeds were dominated by Bacillus sp. The comparative experimental results from hydrogen production performance and microbial community analysis showed that the load-shock treatment method was better than the other four methods for enriching thermophilic hydrogen-producing seeds from anaerobic digested sludge. Load-shock treated sludge was implemented in palm oil mill effluent (POME) fermentation and was found to give maximum hydrogen production rates of 13.34 mmol H(2) l(-1)h(-1) and resulted in a dominance of Thermoanaerobacterium spp. Load-shock treatment is an easy and practical method for enriching thermophilic hydrogen-producing bacteria from anaerobic digested sludge.

  13. Anaerobic biotransformation of estrogens

    Energy Technology Data Exchange (ETDEWEB)

    Czajka, Cynthia P. [Department of Microbiology, University of Manitoba, Winnipeg, MB, R3T 2N2 (Canada); Londry, Kathleen L. [Department of Microbiology, University of Manitoba, Winnipeg, MB, R3T 2N2 (Canada)]. E-mail: londryk@cc.umanitoba.ca

    2006-08-31

    Estrogens are important environmental contaminants that disrupt endocrine systems and feminize male fish. We investigated the potential for anaerobic biodegradation of the estrogens 17-{alpha}-ethynylestradiol (EE2) and 17-{beta}-estradiol (E2) in order to understand their fate in aquatic and terrestrial environments. Cultures were established using lake water and sediment under methanogenic, sulfate-, iron-, and nitrate-reducing conditions. Anaerobic degradation of EE2 (added at 5 mg/L) was not observed in multiple trials over long incubation periods (over three years). E2 (added at 5 mg/L) was transformed to estrone (E1) under all four anaerobic conditions (99-176 {mu}g L{sup -1} day{sup -1}), but the extent of conversion was different for each electron acceptor. The oxidation of E2 to E1 was not inhibited by E1. Under some conditions, reversible inter-conversion of E2 and E1 was observed, and the final steady state concentration of E2 depended on the electron-accepting condition but was independent of the total amount of estrogens added. In addition, racemization occurred and E1 was also transformed to 17-{alpha}-estradiol under all but nitrate-reducing conditions. Although E2 could be readily transformed to E1 and in many cases 17-{alpha}-estradiol under anaerobic conditions, the complete degradation of estrogens under these conditions was minimal, suggesting that they would accumulate in anoxic environments.

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

    Directory of Open Access Journals (Sweden)

    Kimberly M. Webb

    2012-01-01

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

  15. Biological hydrogen production from biomass by thermophilic bacteria

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-07-01

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

  16. Biological hydrogen production from biomass by thermophilic bacteria

    International Nuclear Information System (INIS)

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

  17. Consolidated bioprocessing method using thermophilic microorganisms

    Energy Technology Data Exchange (ETDEWEB)

    Mielenz, Jonathan Richard

    2016-02-02

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

  18. Anaerobic workout

    OpenAIRE

    McAdam, Ewan J.

    2010-01-01

    Anaerobic technology cannot directly replace current wastewater treatment processes exclusively. The UASB reactor configuration removes slightly less organic carbon by comparison as the process relies on lamella separation for passive clarification rather than using fine pores like anMBR. By contrast, whilst anMBR can operate as a single unit process for organic carbon removal, the membrane surface has to be cleaned using gas sparging to limit surface deposition, which requires extra energy. ...

  19. Continuous hydrogen production during fermentation of alpha-cellulose by the thermophillic bacterium Clostridium thermocellum.

    Science.gov (United States)

    Magnusson, Lauren; Cicek, Nazim; Sparling, Richard; Levin, David

    2009-02-15

    Continuous hydrogen (H2) production during fermentation of alpha-cellulose was established using the thermophillic, anaerobic bacterium Clostridium thermocellum ATCC 27405. The objectives of this work were to characterize growth of C. thermocellum, quantify H2 production and determine soluble end-product synthesis patterns during fermentation of a cellulosic substrate under continuous culture conditions. A 5 L working volume fermentor was established and growth experiments were maintained for over 3,000 h. Substrate concentrations were varied from 1 to 4 g/L and the feed was introduced with continuous nitrogen gas sparging to prevent clogging of the feed-line. The pH and temperature of the reactor were maintained at 7.0 and 600 degrees C, respectively, throughout the study. At concentrations above 4 g/L, the delivery of alpha-cellulose was impaired due to feed-line clogging and it became difficult to maintain a homogenous suspension. The highest total gas (H2 plus CO2) production rate, 56.6 mL L(-1) h(-1), was observed at a dilution rate of 0.042 h(-1) and substrate concentration of 4 g/L. Under these conditions, the H2 production rate was 5.06 mmol h(-1). Acetate and ethanol were the major soluble end-products, while lactate and formate were greatly reduced compared to production in batch cultures. Concentrations of all metabolites increased with increasing substrate concentration, with the exception of lactate. Despite a number of short-term electrical and mechanical failures during the testing period, the system recovered quickly, exhibiting substantial robustness. A carbon balance was completed to ensure that all end-products were accounted for, with final results indicating near 100% carbon recovery. This study shows that long-term, stable H2 production can be achieved during direct fermentation of an insoluble cellulosic substrate under continuous culture conditions.

  20. Complete genome sequence of thermophilic Bacillus smithii type strain DSM 4216T

    DEFF Research Database (Denmark)

    Bosma, Elleke Fenna; Koehorst, Jasper J.; van Hijum, Sacha A. F. T.;

    2016-01-01

    Bacillus smithii is a facultatively anaerobic, thermophilic bacterium able to use a variety of sugars that can be derived from lignocellulosic feedstocks. Being genetically accessible, it is a potential new host for biotechnological production of green chemicals from renewable resources. We...... determined the complete genomic sequence of the B. smithii type strain DSM 4216T, which consists of a 3,368,778 bp chromosome (GenBank accession number CP012024.1) and a 12,514 bp plasmid (GenBank accession number CP012025.1), together encoding 3880 genes. Genome annotation via RAST was complemented...

  1. Early Microbial Evolution: The Age of Anaerobes.

    Science.gov (United States)

    Martin, William F; Sousa, Filipa L

    2016-02-01

    In this article, the term "early microbial evolution" refers to the phase of biological history from the emergence of life to the diversification of the first microbial lineages. In the modern era (since we knew about archaea), three debates have emerged on the subject that deserve discussion: (1) thermophilic origins versus mesophilic origins, (2) autotrophic origins versus heterotrophic origins, and (3) how do eukaryotes figure into early evolution. Here, we revisit those debates from the standpoint of newer data. We also consider the perhaps more pressing issue that molecular phylogenies need to recover anaerobic lineages at the base of prokaryotic trees, because O2 is a product of biological evolution; hence, the first microbes had to be anaerobes. If molecular phylogenies do not recover anaerobes basal, something is wrong. Among the anaerobes, hydrogen-dependent autotrophs--acetogens and methanogens--look like good candidates for the ancestral state of physiology in the bacteria and archaea, respectively. New trees tend to indicate that eukaryote cytosolic ribosomes branch within their archaeal homologs, not as sisters to them and, furthermore tend to root archaea within the methanogens. These are major changes in the tree of life, and open up new avenues of thought. Geochemical methane synthesis occurs as a spontaneous, abiotic exergonic reaction at hydrothermal vents. The overall similarity between that reaction and biological methanogenesis fits well with the concept of a methanogenic root for archaea and an autotrophic origin of microbial physiology. PMID:26684184

  2. Anaerobic co-digestion of dairy manure and potato waste

    Science.gov (United States)

    Yadanaparthi, Sai Krishna Reddy

    Dairy and potato are two important agricultural commodities in Idaho. Both the dairy and potato processing industries produce a huge amount of waste which could cause environmental pollution. To minimize the impact of potential pollution associated with dairy manure (DM) and potato waste (PW), anaerobic co-digestion has been considered as one of the best treatment process. The purpose of this research is to evaluate the anaerobic co-digestion of dairy manure and potato waste in terms of process stability, biogas generation, construction and operating costs, and potential revenue. For this purpose, I conducted 1) a literature review, 2) a lab study on anaerobic co-digestion of dairy manure and potato waste at three different temperature ranges (ambient (20-25°C), mesophilic (35-37°C) and thermophilic (55-57°C) with five mixing ratios (DM:PW-100:0, 90:10, 80:20, 60:40, 40:60), and 3) a financial analysis for anaerobic digesters based on assumed different capital costs and the results from the lab co-digestion study. The literature review indicates that several types of organic waste were co-digested with DM. Dairy manure is a suitable base matter for the co-digestion process in terms of digestion process stability and methane (CH4) production (Chapter 2). The lab tests showed that co-digestion of DM with PW was better than digestion of DM alone in terms of biogas and CH4 productions (Chapter 3). The financial analysis reveals DM and PW can be used as substrate for full size anaerobic digesters to generate positive cash flow within a ten year time period. Based on this research, the following conclusions and recommendations were made: ▸ The ratio of DM:PW-80:20 is recommended at thermophilic temperatures and the ratio of DM:PW-90:10 was recommended at mesophilic temperatures for optimum biogas and CH4 productions. ▸ In cases of anaerobic digesters operated with electricity generation equipment (generators), low cost plug flow digesters (capital cost of 600/cow

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

    Science.gov (United States)

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

    2014-06-01

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

  4. Anaerobic biodegradability of macropollutants

    DEFF Research Database (Denmark)

    Angelidaki, Irini

    2002-01-01

    A variety of test procedures for determination of anaerobic biodegradability has been reported. This paper reviews the methods developed for determination of anaerobic biodegradability of macro-pollutants. Anaerobic biodegradability of micro-pollutants is not included. Furthermore, factors import...

  5. Renewable energy and reduction of emission of greenhouse gas by application of advanced techniques for wastewater and sludge treatment at small and medium size wastewater treatment plants. Final report; Erneuerbare Energie und Minderung der Emission von Treibhausgasen durch moderne Verfahren der Abwasser- und Schlammbehandlung auf kleinen und mittleren Klaeranlagen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Huber, A.; Tietze, R.; Luetzner, K.; Kuehn, V.; Barth, M.

    2004-03-19

    In terms of the 'Kreislaufwirtschaftsgesetz' accruing sludge of WWTP has to be minimized. Furthermore should the utilisation of matter and energy be preferred opposite to disposal. In the framework of this project the use of sludge for energy production at small and medium sized WWTP's has been investigated and the reduction of green house gas emission has been evaluated. For significant process steps within the wastewater and sludge treatment resulting potential of green house gas emission as been estimated. As one option in reducing this emission the anaerobe sludge stabilisation implicating use of bio gas can be applied. In this regard the mesophil and thermophil sludge digestion has been compared and evaluated. Emphasis has been put on the investigation with regard to amount of bio gas produced, degradation of organic matter, strain of process water and dewatering. Representative results have been derived from measures over a period of two years of a pilot plant using sludge of small and medium sized WWTP's. The investigation considered two-stage system i.e. mesophil/mesophil as well as thermophil/mesophil operation mode. Furthermore has the change from mesophil to thermophil operation mode been investigated for large WWTP's. For the pilot plant estimation for dimensioning have been developed considering significant aspects present at small and medium sized WWTP's. Finally has the anaerobe sludge stabilisation been economically evaluated allowing conclusions for similar systems in practice. (orig.)

  6. Enhancing ethanol production from thermophilic and mesophilic solid digestate using ozone combined with aqueous ammonia pretreatment.

    Science.gov (United States)

    Wang, Dianlong; Xi, Jiang; Ai, Ping; Yu, Liang; Zhai, Hong; Yan, Shuiping; Zhang, Yanlin

    2016-05-01

    Pretreatment with ozone combined with aqueous ammonia was used to recover residual organic carbon from recalcitrant solid digestate for ethanol production after anaerobic digestion (AD) of rice straw. Methane yield of AD at mesophilic and thermophilic conditions, and ethanol production of solid digestate were investigated. The results showed that the methane yield at thermophilic temperature was 72.2% higher than that at mesophilic temperature under the same conditions of 24days and 17% solid concentration. And also the ethanol production efficiency of solid digestate after thermophilic process was 24.3% higher than that of solid digestate after mesophilic process. In this study, the optimal conditions for integrated methane and ethanol processes were determined as 55°C, 17% solid concentration and 24days. 58.6% of glucose conversion, 142.8g/kg of methane yield and 65.2g/kg of ethanol yield were achieved, and the highest net energy balance was calculated as 6416kJ/kg.

  7. Comparative microbiological-hygienic studies in mesophilic and thermophilic fouling of sewage sludge

    Energy Technology Data Exchange (ETDEWEB)

    Pohlig-Schmitt, M.; Philipp, W.; Wekerle, J.; Strauch, D.

    Investigations concerning the inactivation of microbial pathogens (bacteria, viruses and parasites) during anaerobic, alkaline dignestion of sludge are described. A thermophilic (54/sup 0/C) and a mesophilic (34/sup 0/C) operated biogas model plant were compared from the point of view of hygiene. Is was found that in the thermophilic process Salmonella senftenberg survived 13,5 h, Streptococcus faecium 55 h, Streptococcus faecalis 42 h and Klebsiella pneumoniae 0,5 h. Within 30 min eggs of Ascaris suum lost their infectivity Bovine Parvovirus was inactivated after 1 d to 2 d treatment. Survival times under mesophilic conditions of 13 d for Salmonella senftenberg and more than 8 mouth for Streptococcus faecium were found. Poliovirus Type 1 was inactivated in 8 d while Bovine Parvovirus survived no longer than 15 d. The results obtained in the thermophilic process were compared to those after heat treatment of the test microorganisms in ampules exposed in a wather-bath under defined conditions to 54/sup 0/C. It was found, that the bacteria survived only about half the time in this case. Poliovirus Type 1 was inactivated after 0,75 h and Bovine Parvovirus after 7 d exposure. (orig.RB)

  8. Enhancing ethanol production from thermophilic and mesophilic solid digestate using ozone combined with aqueous ammonia pretreatment.

    Science.gov (United States)

    Wang, Dianlong; Xi, Jiang; Ai, Ping; Yu, Liang; Zhai, Hong; Yan, Shuiping; Zhang, Yanlin

    2016-05-01

    Pretreatment with ozone combined with aqueous ammonia was used to recover residual organic carbon from recalcitrant solid digestate for ethanol production after anaerobic digestion (AD) of rice straw. Methane yield of AD at mesophilic and thermophilic conditions, and ethanol production of solid digestate were investigated. The results showed that the methane yield at thermophilic temperature was 72.2% higher than that at mesophilic temperature under the same conditions of 24days and 17% solid concentration. And also the ethanol production efficiency of solid digestate after thermophilic process was 24.3% higher than that of solid digestate after mesophilic process. In this study, the optimal conditions for integrated methane and ethanol processes were determined as 55°C, 17% solid concentration and 24days. 58.6% of glucose conversion, 142.8g/kg of methane yield and 65.2g/kg of ethanol yield were achieved, and the highest net energy balance was calculated as 6416kJ/kg. PMID:26868156

  9. Bioleaching of marmatite using moderately thermophilic bacteria

    Institute of Scientific and Technical Information of China (English)

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

    2008-01-01

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

  10. Anaerobic biorefinery: Current status, challenges, and opportunities.

    Science.gov (United States)

    Sawatdeenarunat, Chayanon; Nguyen, Duc; Surendra, K C; Shrestha, Shilva; Rajendran, Karthik; Oechsner, Hans; Xie, Li; Khanal, Samir Kumar

    2016-09-01

    Anaerobic digestion (AD) has been in use for many decades. To date, it has been primarily aimed at treating organic wastes, mainly manures and wastewater sludge, and industrial wastewaters. However, with the current advancements, a more open mind is required to look beyond these somewhat restricted original applications of AD. Biorefineries are such concepts, where multiple products including chemicals, fuels, polymers etc. are produced from organic feedstocks. The anaerobic biorefinery concept is now gaining increased attention, utilizing AD as the final disposal step. This review aims at evaluating the potential significance of anaerobic biorefineries, including types of feedstocks, uses for the produced energy, as well as sustainable applications of the generated residual digestate. A comprehensive analysis of various types of anaerobic biorefineries has been developed, including both large-scale and household level applications. Finally, future directives are highlighted showing how anaerobic biorefinery concept could impact the bioeconomy in the near future. PMID:27005786

  11. Biodegradation of Aliphatic-aromatic Coplyester under Thermophilic Conditions

    Directory of Open Access Journals (Sweden)

    Elsayed B. Belal

    2013-11-01

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

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

    Science.gov (United States)

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

    2013-09-01

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

  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. Potential Application of Anaerobic Extremophiles for Hydrogen Production

    Science.gov (United States)

    Pikuta, Elena V.; Hoover, Richard B.

    2004-01-01

    During substrate fermentation many anaerobes produce the hydrogen as a waste product, which often regulates the growth of the cultures as an inhibitor. In nature the hydrogen is usually removed from the ecosystem due to its physical properties or by consumption of hydrogen by secondary anaerobes, which sometimes behave as competitors for electron donors as is seen in the classical example in anaerobic microbial communities via the interaction between methanogens and sulfate- or sulfur- reducers. It was demonstrated previously on mixed cultures of anaerobes at neutral pH that bacterial hydrogen production could provide an alternative energy source. But at neutral pH the original cultures can easily be contaminated by methanogens, a most unpleasant side effect of these conditions is the development of pathogenic bacteria. In both cases the rate of hydrogen production was dramatically decreased since some part of the hydrogen was transformed to methane, and the cultivation of human pathogens on a global scale is very dangerous. In our laboratory, experiments with obligately alkaliphilic bacteria that excrete hydrogen as the end metabolic product were performed at different temperature regimes. Mesophilic and moderately thermophilic bacterial cultures have been studied and compared for the most effective hydrogen production. For high-mineralized media with pH 9.5-10.0 not many methanogens are known to exist. Furthermore, the development of pathogenic contaminant microorganisms is virtually impossible: carbonate-saturated solutions are used as antiseptics in medicine. Therefore the cultivation of alkaliphilic hydrogen producing bacteria could be considered as most safe process for global Scale industry in future. Here we present experimental data on the rates of hydrogen productivity for mesophilic, alkaliphilic, obligately anaerobic bacterium Spirocheta americana ASpG1 and moderately thermophilic, alkaliphilic, facultative anaerobe Anoxybacillus pushchinoensis K1 and

  15. Oxygen tolerance capacity of upflow anaerobic solid-state (UASS) with anaerobic filter (AF) system.

    Science.gov (United States)

    Meng, Yao; Jost, Carsten; Mumme, Jan; Wang, Kaijun; Linke, Bernd

    2016-07-01

    In order to investigate the oxygen tolerance capacity of upflow anaerobic solid-state (UASS) with anaerobic filter (AF) system, the effect of microaeration on thermophilic anaerobic digestion of maize straw was investigated under batch conditions and in the UASS with AF system. Aeration intensities of 0-431mL O2/gvs were conducted as pretreatment under batch conditions. Aeration pretreatment obviously enhanced anaerobic digestion and an aeration intensity of 431mL O2/gvs increased the methane yield by 82.2%. Aeration intensities of 0-355mL O2/gvs were conducted in the process liquor circulation of the UASS with AF system. Dissolved oxygen (DO) of UASS and AF reactors kept around 1.39±0.27 and 0.99±0.38mg/L, respectively. pH was relatively stable around 7.11±0.04. Volatile fatty acids and soluble chemical oxygen demand concentration in UASS reactor were higher than those in AF reactor. Methane yield of the whole system was almost stable at 85±7mL/gvs as aeration intensity increased step by step. The UASS with AF system showed good oxygen tolerance capacity. PMID:27372134

  16. Strategies for the anaerobic digestion of the organic fraction of municipal solid waste: an overview

    DEFF Research Database (Denmark)

    Hartmann, H.; Ahring, Birgitte Kiær

    2006-01-01

    Different process strategies for anaerobic digestion of the organic fraction of municipal solid waste (OFMSW) are reviewed weighing high-solids versus low-solids, mesophilic versus thermophilic and single-stage versus multi-stage processes. The influence of different waste characteristics...... such as composition of biodegradable fractions, C:N ratio and particle size is described. Generally, source sorting of OFMSW and a high content of food waste leads to higher biogas yields than the use of mechanically sorted OFMSW. Thermophilic processes are more efficient than mesophilic processes in terms of higher...... biogas yields at different organic loading rates (OLR). Highest biogas yields are achieved by means of wet thermophilic processes at OLRs lower than 6 kg-VS(.)m(-3) d(-1). High-solids processes appear to be relatively more efficient when OLRs higher than 6 kg-VS(.)m(-3) d(-1) are applied. Multi...

  17. Low pH (6, 5, and 4) sulfate reduction during the acidification of sucrose under thermophilic (55°C) conditions

    NARCIS (Netherlands)

    Lopes, S.I.C.; Sulistyawati, I.; Capela, M.I.; Lens, P.N.L.

    2007-01-01

    The effect of a low pH (6, 5 and 4) and different COD/SO42¿ ratios (9 and 3.5) on thermophilic (55 °C) sulfate reduction and acidification of sucrose was investigated using three upflow anaerobic sludge bed reactors fed with sucrose at an organic loading rate of 3.5 gCOD (lreactor d)¿1. The three re

  18. Thermophilic co-digestion of organic fraction of municipal solid wastes with FOG wastes from a sewage treatment plant : reactor performance and microbial community monitoring

    OpenAIRE

    Martín-González, Lucia; Castro, Rita; M. A. PEREIRA; Alves, M. M.; Font, Xavier; Vicent, Teresa

    2012-01-01

    Working at thermophilic conditions instead of mesophilic, and also the addition of a co-substrate, are both ways to intend to improve the anaerobic digestion of the source-collected organic fraction of municipal solid wastes (SC-OFMSW). Addition of sewage treatment plant fat, oil and grease wastes (STP-FOGW), that are nowadays sent to landfill, would represent an opportunity to recover a wasted methane potential and, moreover, improve the whole process. In this study, after a first period fee...

  19. Are thermophilic microorganisms active in cold environments?

    Science.gov (United States)

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

    2015-07-01

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

  20. Thermophilic starter cultures: another set of problems

    OpenAIRE

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

    1993-01-01

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

  1. Prospects of Anaerobic Digestion Technology in China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    As the world's largest developing country, China must face the problem of managing municipal solid waste, and the challenge of organic waste disposal is even more serious. Considering the characteristics of traditional waste disposal technologies and the subsequent secondary pollution, anaerobic digestion has various advantages such as reduction in the land needed for disposal and preservation of environmental quality. In light of the energy crisis, this paper focuses on the potential production of biogas from biowaste through anaerobic digestion processes, the problems incurred by the waste collection system, and the efficiency of the anaerobic digestion process. Use of biogas in a combined heat and power cogeneration system is also discussed. Finally, the advantages of anaerobic digestion technology for the Chinese market are summarized. The anaerobic digestion is suggested to be a promising treating technology for the organic wastes in China.

  2. Anaerobic digestion of slaughterhouse by-products

    Energy Technology Data Exchange (ETDEWEB)

    Hejnfelt, Anette; Angelidaki, Irini [Department of Environmental Engineering, Technical University of Denmark, DTU, Building 113, DK-2800 Kgs. Lyngby (Denmark)

    2009-08-15

    Anaerobic digestion of animal by-products was investigated in batch and semi-continuously fed, reactor experiments at 55 C and for some experiments also at 37 C. Separate or mixed by-products from pigs were tested. The methane potential measured by batch assays for meat- and bone flour, fat, blood, hair, meat, ribs, raw waste were: 225, 497, 487, 561, 582, 575, 359, 619 dm{sup 3} kg{sup -1} respectively, corresponding to 50-100% of the calculated theoretical methane potential. Dilution of the by-products had a positive effect on the specific methane yield with the highest dilutions giving the best results. High concentrations of long-chain fatty acids and ammonia in the by-products were found to inhibit the biogas process at concentrations higher than 5 g lipids dm{sup -3} and 7 g N dm{sup -3} respectively. Pretreatment (pasteurization: 70 C, sterilization: 133 C), and alkali hydrolysis (NaOH) had no effect on achieved methane yields. Mesophilic digestion was more stable than thermophilic digestion, and higher methane yield was noticed at high waste concentrations. The lower yield at thermophilic temperature and high waste concentration was due to ammonia inhibition. Co-digestion of 5% pork by-products mixed with pig manure at 37 C showed 40% higher methane production compared to digestion of manure alone. (author)

  3. Early-warning process/control for anaerobic digestion and biological nitrogen transformation processes: Batch, semi-continuous, and/or chemostat experiments. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hickey, R. [Science Applications International Corp., McLean, VA (United States)

    1992-09-01

    The objective of this project was to develop and test an early-warning/process control model for anaerobic sludge digestion (AD). The approach was to use batch and semi-continuously fed systems and to assemble system parameter data on a real-time basis. Specific goals were to produce a real-time early warning control model and computer code, tested for internal and external validity; to determine the minimum rate of data collection for maximum lag time to predict failure with a prescribed accuracy and confidence in the prediction; and to determine and characterize any trends in the real-time data collected in response to particular perturbations to feedstock quality. Trends in the response of trace gases carbon monoxide and hydrogen in batch experiments, were found to depend on toxicant type. For example, these trace gases respond differently for organic substances vs. heavy metals. In both batch and semi-continuously feed experiments, increased organic loading lead to proportionate increases in gas production rates as well as increases in CO and H{sub 2} concentration. An analysis of variance of gas parameters confirmed that CO was the most sensitive indicator variable by virtue of its relatively larger variance compared to the others. The other parameters evaluated including gas production, methane production, hydrogen, carbon monoxide, carbon dioxide and methane concentration. In addition, a relationship was hypothesized between gaseous CO concentration and acetate concentrations in the digester. The data from semicontinuous feed experiments were supportive.

  4. Anaerobic digestion for simultaneous sewage sludge treatment and CO biomethanation: process performance and microbial ecology

    DEFF Research Database (Denmark)

    Luo, Gang; Wang, Wen; Angelidaki, Irini

    2013-01-01

    in an anaerobic reactor was presented. Batch experiments showed that CO was inhibitory to methanogens, but not to bacteria, at CO partial pressure between 0.25 and 1 atm under thermophilic conditions. During anaerobic digestion of sewage sludge supplemented with CO added through a hollow fiber membrane (HFM....... However, the two species were distributed differently in the liquid phase and in the biofilm. Although carboxidotrophic activities test showed that CO was converted by both archaea and bacteria, the bacterial species responsible for CO conversion are unknown....

  5. 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.

  6. Impact of sludge thickening on energy recovery from anaerobic digestion[Held jointly with the 4. Canadian organic residuals and biosolids managment conference

    Energy Technology Data Exchange (ETDEWEB)

    Puchajda, B. [Stantec Consulting Ltd., Winnipeg, MB (Canada); Oleszkiewicz, J. [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Civil Engineering

    2007-07-01

    The anaerobic digestion of wastewater sludge leads to production of a biogas mixture of methane and carbon dioxide. The technology of anaerobic digestion has been applied in various configurations and generally claims greater biogas production and additional stability to the process as compared to conventional mesophilic anaerobic digestion. However, biogas production is only one of many components of anaerobic digester energy balance. This paper presented energy balances for various digestion systems, including single mesophilic digestion; single thermophilic digestion; two-stage thermophilic-mesophilic digestion; and systems at elevated solids content in sludge. Energy balance included two components, namely energy demand and recoverable energy. Energy demand is defined as energy required for process operation such as heat requirement to elevate sludge temperature, and heat losses through digesters walls. Recoverable energy is defined as energy associated with methane content in biogas, that can be recovered either in the form of heat or electricity, and heat recovered through heat exchangers. The paper identified the assumptions used in all energy balance calculations. It presented the objectives and methods of the study as well as the results. It was concluded that two-stage thermophilic-mesophilic digestion system generate more available energy than single mesophilic digestion and single thermophilic digestion systems. Sludge thickening offers the greatest amount of available energy. However, that energy surplus is offset by the cost of thickening. 12 refs., 3 tabs., 6 figs.

  7. Thermophilic biohydrogen production: how far are we?

    Science.gov (United States)

    Pawar, Sudhanshu S; van Niel, Ed W J

    2013-09-01

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

  8. Thermophilic methane production and oxidation in compost.

    Science.gov (United States)

    Jäckel, Udo; Thummes, Kathrin; Kämpfer, Peter

    2005-04-01

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

  9. Thermophilic biohydrogen production: how far are we?

    Science.gov (United States)

    Pawar, Sudhanshu S; van Niel, Ed W J

    2013-09-01

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

  10. 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

  11. Anaerobic transformation of carbon monoxide by microbial communities of Kamchatka hot springs.

    Science.gov (United States)

    Kochetkova, Tatiana V; Rusanov, Igor I; Pimenov, Nikolay V; Kolganova, Tatyana V; Lebedinsky, Alexander V; Bonch-Osmolovskaya, Elizaveta A; Sokolova, Tatyana G

    2011-05-01

    Carbon monoxide (CO) is one of the common gaseous compounds found in hot volcanic environments. It is known to serve as the growth substrate for a number of thermophilic prokaryotes, both aerobic and anaerobic. The goal of this work was to study the process of anaerobic transformation of CO by microbial communities inhabiting natural thermal environments: hot springs of Uzon Caldera, Kamchatka. The anaerobic microbial community of Treshchinny Spring (80°C, pH 6.5) was found to exhibit two peaks of affinity for CO (K (S1) = 54 nM and K (S2) = 1 μM). The actual rate of anaerobic CO transformation by the microbial community of this spring, calculated after obtaining the concentration dependence curve and extrapolated to the natural concentration of CO dissolved in the hot spring water (20 nM), was found to be 120 μmol l(-1) of sediment day(-1). In all the hot springs studied, more than 90% of the carbon of (14)CO upon anaerobic incubation was recovered as (14)CO(2). From 1 to 5% of (14)CO was transformed to volatile fatty acids (VFA). The number of microorganisms capable of anaerobic CO oxidation determined by dilution-to-extinction method reached 10(6) cells ml(-1) of sediment. CO-transforming anaerobic thermophilic microorganisms isolated from the springs under study exhibited hydrogenogenic type of CO oxidation and belonged to the bacterial genera Carboxydocella and Dictyoglomus. These data suggest a significant role of hydrogenogenic carboxydotrophic prokaryotes in anaerobic CO transformation in Uzon Caldera hot springs.

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

    Energy Technology Data Exchange (ETDEWEB)

    Stoll, U.

    1988-01-01

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

  13. The anaerobic corrosion of carbon steel in concrete

    International Nuclear Information System (INIS)

    This is the final report of a 2 year programme aimed at (1) determining the rate of anaerobic corrosion of steel in concrete, (2) investigating the nature of the corrosion products formed on carbon steel embedded in cementitious material under anaerobic conditions and (3) evaluating the effect of hydrogen over-pressures on the rate of anaerobic corrosion. All experiments have been carried out at temperatures in the range 20-300C, ie ambient conditions. 4 refs.; 19 figs.; 6 tabs

  14. Boosting dark fermentation with co-cultures of extreme thermophiles for biohythane production from garden waste.

    Science.gov (United States)

    Abreu, Angela A; Tavares, Fábio; Alves, Maria Madalena; Pereira, Maria Alcina

    2016-11-01

    Proof of principle of biohythane and potential energy production from garden waste (GW) is demonstrated in this study in a two-step process coupling dark fermentation and anaerobic digestion. The synergistic effect of using co-cultures of extreme thermophiles to intensify biohydrogen dark fermentation is demonstrated using xylose, cellobiose and GW. Co-culture of Caldicellulosiruptor saccharolyticus and Thermotoga maritima showed higher hydrogen production yields from xylose (2.7±0.1molmol(-1) total sugar) and cellobiose (4.8±0.3molmol(-1) total sugar) compared to individual cultures. Co-culture of extreme thermophiles C. saccharolyticus and Caldicellulosiruptor bescii increased synergistically the hydrogen production yield from GW (98.3±6.9Lkg(-1) (VS)) compared to individual cultures and co-culture of T. maritima and C. saccharolyticus. The biochemical methane potential of the fermentation end-products was 322±10Lkg(-1) (CODt). Biohythane, a biogas enriched with 15% hydrogen could be obtained from GW, yielding a potential energy generation of 22.2MJkg(-1) (VS). PMID:27484669

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

    Science.gov (United States)

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

    2011-02-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2002-07-01

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

  17. Boosting dark fermentation with co-cultures of extreme thermophiles for biohythane production from garden waste.

    Science.gov (United States)

    Abreu, Angela A; Tavares, Fábio; Alves, Maria Madalena; Pereira, Maria Alcina

    2016-11-01

    Proof of principle of biohythane and potential energy production from garden waste (GW) is demonstrated in this study in a two-step process coupling dark fermentation and anaerobic digestion. The synergistic effect of using co-cultures of extreme thermophiles to intensify biohydrogen dark fermentation is demonstrated using xylose, cellobiose and GW. Co-culture of Caldicellulosiruptor saccharolyticus and Thermotoga maritima showed higher hydrogen production yields from xylose (2.7±0.1molmol(-1) total sugar) and cellobiose (4.8±0.3molmol(-1) total sugar) compared to individual cultures. Co-culture of extreme thermophiles C. saccharolyticus and Caldicellulosiruptor bescii increased synergistically the hydrogen production yield from GW (98.3±6.9Lkg(-1) (VS)) compared to individual cultures and co-culture of T. maritima and C. saccharolyticus. The biochemical methane potential of the fermentation end-products was 322±10Lkg(-1) (CODt). Biohythane, a biogas enriched with 15% hydrogen could be obtained from GW, yielding a potential energy generation of 22.2MJkg(-1) (VS).

  18. Saponification of fatty slaughterhouse wastes for enhancing anaerobic biodegradability.

    Science.gov (United States)

    Battimelli, Audrey; Carrère, Hélène; Delgenès, Jean-Philippe

    2009-08-01

    The thermochemical pretreatment by saponification of two kinds of fatty slaughterhouse waste--aeroflotation fats and flesh fats from animal carcasses--was studied in order to improve the waste's anaerobic degradation. The effect of an easily biodegradable compound, ethanol, on raw waste biodegradation was also examined. The aims of the study were to enhance the methanisation of fatty waste and also to show a link between biodegradability and bio-availability. The anaerobic digestion of raw waste, saponified waste and waste with a co-substrate was carried out in batch mode under mesophilic and thermophilic conditions. The results showed little increase in the total volume of biogas, indicating a good biodegradability of the raw wastes. Mean biogas volume reached 1200 mL/g VS which represented more than 90% of the maximal theoretical biogas potential. Raw fatty wastes were slowly biodegraded whereas pretreated wastes showed improved initial reaction kinetics, indicating a better initial bio-availability, particularly for mesophilic runs. The effects observed for raw wastes with ethanol as co-substrate depended on the process temperature: in mesophilic conditions, an initial improvement was observed whereas in thermophilic conditions a significant decrease in biodegradability was observed.

  19. Horse manure as feedstock for anaerobic digestion.

    Science.gov (United States)

    Hadin, Sa; Eriksson, Ola

    2016-10-01

    Horse keeping is of great economic, social and environmental benefit for society, but causes environmental impacts throughout the whole chain from feed production to manure treatment. According to national statistics, the number of horses in Sweden is continually increasing and is currently approximately 360,000. This in turn leads to increasing amounts of horse manure that have to be managed and treated. Current practices could cause local and global environmental impacts due to poor performance or lack of proper management. Horse manure with its content of nutrients and organic material can however contribute to fertilisation of arable land and recovery of renewable energy following anaerobic digestion. At present anaerobic digestion of horse manure is not a common treatment. In this paper the potential for producing biogas and biofertiliser from horse manure is analysed based on a thorough literature review in combination with mathematical modelling and simulations. Anaerobic digestion was chosen as it has a high degree of resource conservation, both in terms of energy (biogas) and nutrients (digestate). Important factors regarding manure characteristics and operating factors in the biogas plant are identified. Two crucial factors are the type and amount of bedding material used, which has strong implications for feedstock characteristics, and the type of digestion method applied (dry or wet process). Straw and waste paper are identified as the best materials in an energy point of view. While the specific methane yield decreases with a high amount of bedding, the bedding material still makes a positive contribution to the energy balance. Thermophilic digestion increases the methane generation rate and yield, compared with mesophilic digestion, but the total effect is negligible.

  20. Horse manure as feedstock for anaerobic digestion.

    Science.gov (United States)

    Hadin, Sa; Eriksson, Ola

    2016-10-01

    Horse keeping is of great economic, social and environmental benefit for society, but causes environmental impacts throughout the whole chain from feed production to manure treatment. According to national statistics, the number of horses in Sweden is continually increasing and is currently approximately 360,000. This in turn leads to increasing amounts of horse manure that have to be managed and treated. Current practices could cause local and global environmental impacts due to poor performance or lack of proper management. Horse manure with its content of nutrients and organic material can however contribute to fertilisation of arable land and recovery of renewable energy following anaerobic digestion. At present anaerobic digestion of horse manure is not a common treatment. In this paper the potential for producing biogas and biofertiliser from horse manure is analysed based on a thorough literature review in combination with mathematical modelling and simulations. Anaerobic digestion was chosen as it has a high degree of resource conservation, both in terms of energy (biogas) and nutrients (digestate). Important factors regarding manure characteristics and operating factors in the biogas plant are identified. Two crucial factors are the type and amount of bedding material used, which has strong implications for feedstock characteristics, and the type of digestion method applied (dry or wet process). Straw and waste paper are identified as the best materials in an energy point of view. While the specific methane yield decreases with a high amount of bedding, the bedding material still makes a positive contribution to the energy balance. Thermophilic digestion increases the methane generation rate and yield, compared with mesophilic digestion, but the total effect is negligible. PMID:27396682

  1. Gender comparisons in anaerobic power and anaerobic capacity tests.

    OpenAIRE

    Maud, P. J.; Shultz, B B

    1986-01-01

    The purpose of the study was to compare anaerobic power and anaerobic capacity test scores between young active men and women. Three performance measures of anaerobic power and two of anaerobic capacity were administered to a sample comprising 52 male and 50 female college students (means age = 21.4 yrs). Results indicated significant differences between men and women in body height, weight and per cent fat, in fat free mass (FFM), anaerobic power, and anaerobic capacity when recorded as gros...

  2. Modelling of two-stage anaerobic digestion using the IWA Anaerobic Digestion Model No. 1 (ADM1).

    Science.gov (United States)

    Blumensaat, F; Keller, J

    2005-01-01

    The aim of the study presented was to implement a process model to simulate the dynamic behaviour of a pilot-scale process for anaerobic two-stage digestion of sewage sludge. The model implemented was initiated to support experimental investigations of the anaerobic two-stage digestion process. The model concept implemented in the simulation software package MATLAB/Simulink is a derivative of the IWA Anaerobic Digestion Model No.1 (ADM1) that has been developed by the IWA task group for mathematical modelling of anaerobic processes. In the present study the original model concept has been adapted and applied to replicate a two-stage digestion process. Testing procedures, including balance checks and 'benchmarking' tests were carried out to verify the accuracy of the implementation. These combined measures ensured a faultless model implementation without numerical inconsistencies. Parameters for both, the thermophilic and the mesophilic process stage, have been estimated successfully using data from lab-scale experiments described in literature. Due to the high number of parameters in the structured model, it was necessary to develop a customised procedure that limited the range of parameters to be estimated. The accuracy of the optimised parameter sets has been assessed against experimental data from pilot-scale experiments. Under these conditions, the model predicted reasonably well the dynamic behaviour of a two-stage digestion process in pilot scale. PMID:15607176

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

    OpenAIRE

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

    2007-01-01

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

  4. Thermophilic co-digestion of organic fraction of municipal solid wastes with FOG wastes from a sewage treatment plant: reactor performance and microbial community monitoring.

    Science.gov (United States)

    Martín-González, Lucia; Castro, Rita; Pereira, M Alcina; Alves, M Madalena; Font, Xavier; Vicent, Teresa

    2011-04-01

    Working at thermophilic conditions instead of mesophilic, and also the addition of a co-substrate, are both the ways to intend to improve the anaerobic digestion of the source-collected organic fraction of municipal solid wastes (SC-OFMSW). Addition of sewage treatment plant fat, oil and grease wastes (STP-FOGW), that are nowadays sent to landfill, would represent an opportunity to recover a wasted methane potential and, moreover, improve the whole process. In this study, after a first period feeding only SC-OFMSW, a co-digestion step was performed maintaining thermophilic conditions. During the co-digestion period enhancements in biogas production (52%) and methane yield (36%) were achieved. In addition, monitoring of microbial structure by using PCR-DGGE and cloning techniques showed that bacterial community profiles clustered in two distinct groups, before and after the extended contact with STP-FOGW, being more affected by the STP-FOGW addition than the archaeal one.

  5. Aerobic Thermophilic Composting of Municipal Solid Waste

    Directory of Open Access Journals (Sweden)

    D V Wadkar

    2013-03-01

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

  6. Anaerobic digestion of biowastes; Biojaetteen anaerobinen hajottaminen

    Energy Technology Data Exchange (ETDEWEB)

    Kymaelaeinen, M. [Haeme Polytechnic, Haemeenlinna (Finland)

    2005-07-01

    Caused by the demand for potential treatment options for biowastes, an interest on anaerobic digestion (AD) technology, i.e. biogasification, has clearly being increasing in Finland. There has been a need to increase knowledge and offer research facilities for the companies and other parties concerned. In this project, first, research and analytical facilities for AD studies were set up and tested. A mixture of a nitrogen rich waste (poultry slaughterhouse waste, PSHW) and a carbon rich waste (modified potato starch waste, PSW) was selected for the codigestion studies with sewage sludge (SS). The codigestion was studied in thermophilic lab-scale digesters (2x10 and 30 liters), and the startup of thermophilic digestion was clarified, in general. Typically, the PSHW must be treated at low load and long retention time due to the high concentration of lipids and proteins and their potential toxic degradation products such as long-chained fatty acids (LCFAs) and ammonia. The codigestion can help in lowering the effects of these toxic compounds. In this work, based on the experiments in 10 liters reactors fed with a fixed mixture of 2% PSHW, 8% PSW and 90% of SS, high loads of 2-4 kgVS/m3d and SRTs of 30 to 15 days could be applied. Good VS destruction could be achieved with 30 d SRT (76%) and 20 d SRT (55%). Based on the tests in 30 liters reactor fed with a varied mixture of the above mentioned wastes, high load of 4,8 kgVS/m{sup 3}d and SRT of 22 days with a mixture of 10% PSHW, 14% PSW and 76% of SS was also successfully applied. This resulted in the biogas production of about 0,7 Nm3/kgVSfed and VS reduction of around 70%. The critical process parameters were monitored in order to avoid the overloading of these digestion processes. The startup of thermophilic reactors with mesophilic digested sludge as inocula was successfully demonstrated. The findings increased the understanding and learned to control the startup and loading of AD processes thus encouraging the

  7. Anaerobic Digestion: Process

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Batstone, Damien J.

    2011-01-01

    with very little dry matter may also be called a digest. The digest should not be termed compost unless it specifically has been composted in an aerated step. This chapter describes the basic processes of anaerobic digestion. Chapter 9.5 describes the anaerobic treatment technologies, and Chapter 9...

  8. Anaerobic sludge granulation

    NARCIS (Netherlands)

    Hulshoff Pol, L.W.; Castro Lopes, de S.I.; Lettinga, G.; Lens, P.N.L.

    2004-01-01

    This paper reviews different theories on anaerobic sludge granulation in UASB-reactors that have been proposed during the past two decades
    This paper reviews different theories on anaerobic sludge granulation in UASB-reactors that have been proposed during the past two decades. The initial stage

  9. Enhanced mesophilic anaerobic digestion of food waste by thermal pretreatment: Substrate versus digestate heating.

    Science.gov (United States)

    Ariunbaatar, Javkhlan; Panico, Antonio; Yeh, Daniel H; Pirozzi, Francesco; Lens, Piet N L; Esposito, Giovanni

    2015-12-01

    Food waste (FW) represents a source of high potential renewable energy if properly treated with anaerobic digestion (AD). Pretreating the substrates could yield a higher biomethane production in a shorter time. In this study, the effects of thermal (heating the FW in a separate chamber) and thermophilic (heating the full reactor content containing both FW and inoculum) pretreatments at 50, 60, 70 and 80°C prior to mesophilic AD were studied through a series of batch experiments. Pretreatments at a lower temperature (50°C) and a shorter time (biomethane production with an increase by 44-46% was achieved with a thermophilic pretreatment at 50°C for 6-12h or a thermal pretreatment at 80°C for 1.5h. Thermophilic pretreatments at higher temperatures (>55°C) and longer operating times (>12h) yielded higher soluble chemical oxygen demand (CODs), but had a negative effect on the methanogenic activity. The thermal pretreatments at the same conditions resulted in a lower solubilization of COD. Based on net energy calculations, the enhanced biomethane production is sufficient to heat up the FW for the thermal, but not for the thermophilic pretreatment. PMID:26272711

  10. 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.

  11. Microbial community structure associated with the high loading anaerobic codigestion of olive mill and abattoir wastewaters.

    Science.gov (United States)

    Gannoun, Hana; Omri, Ilhem; Chouari, Rakia; Khelifi, Eltaief; Keskes, Sajiaa; Godon, Jean-Jacques; Hamdi, Moktar; Sghir, Abdelghani; Bouallagui, Hassib

    2016-02-01

    The effect of increasing the organic loading rates (OLRs) on the performance of the anaerobic codigestion of olive mill (OMW) and abattoir wastewaters (AW) was investigated under mesophilic and thermophilic conditions. The structure of the microbial community was also monitored. Increasing OLR to 9g of chemical oxygen demand (COD) L(-1)d(-1) affected significantly the biogas yield and microbial diversity at 35°C. However, at 55°C digester remained stable until OLR of 12g of CODL(-1)d(-1) with higher COD removal (80%) and biogas yield (0.52Lg(-1) COD removed). Significant differences in the bacterial communities were detected between mesophilic and thermophilic conditions. The dominant phyla detected in the digester at both phases were the Firmicutes, Actinobacteria, Bacteroidetes, Synergistetes and Spirochaete. However, Verrucomicrobia, Proteobacteria and the candidate division BRC1 were only detected at thermophilic conditions. The Methanobacteriales and the Thermoplasmales were found as a high predominant archaeal member in the anaerobic sludge. PMID:26687494

  12. Digester performance and microbial community changes in thermophilic and mesophilic sequencing batch reactors fed with the fine sieved fraction of municipal sewage.

    Science.gov (United States)

    Ghasimi, Dara S M; Tao, Yu; de Kreuk, Merle; Abbas, Ben; Zandvoort, Marcel H; van Lier, Jules B

    2015-12-15

    This study investigates the start-up and operation of bench-scale mesophilic (35 °C) and thermophilic (55 °C) anaerobic sequencing batch reactor (SBR) digesters treating the fine sieved fraction (FSF) from raw municipal sewage. FSF was sequestered from raw municipal wastewater, in the Netherlands, using a rotating belt filter equipped with a 350 micron mesh. For the given wastewater, the major component of FSF was toilet paper, which is estimated to be 10-14 kg per year per average person in the western European countries. A seven months adaptation time was allowed for the thermophilic and mesophilic digesters in order to adapt to FSF as the sole substrate with varying dry solids content of 10-25%. Different SBR cycle durations (14, 9 and 2 days) were applied for both temperature conditions to study methane production rates, volatile fatty acids (VFAs) dynamics, lag phases, as well as changes in microbial communities. The prevailing sludge in the two digesters consisted of very different bacterial and archaeal communities, with OP9 lineage and Methanothermobacter being pre-dominant in the thermophilic digester and Bacteroides and Methanosaeta dominating the mesophilic one. Eventually, decreasing the SBR cycle period, thus increasing the FSF load, resulted in improved digester performances, particularly with regard to the thermophilic digester, i.e. shortened lag phases following the batch feedings, and reduced VFA peaks. Over time, the thermophilic digester outperformed the mesophilic one with 15% increased volatile solids (VS) destruction, irrespective to lower species diversity found at high temperature.

  13. 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 endos...... organism to exploit the temporarily fluctuating growth conditions in the hydrothermal vent environments of Lake Tanganyika...... endospores. Based on the 16 S rDNA sequence the novel strain was homologous to Thermobrachium celere and Caloramator indicus, which are closely related. The novel strain was strictly anaerobic, fermentative and had a doubling time as short as 10 min during growth on complex substrates, such as yeast extract...... 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...

  14. Thermophilic Sulfate-Reducing Bacteria in Cold Marine Sediment

    DEFF Research Database (Denmark)

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

    1994-01-01

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

  15. Anaerobic Digestion and its Applications

    Science.gov (United States)

    Anaerobic digestion is a natural biological process. The initials "AD" may refer to the process of anaerobic digestion, or the built systems of anaerobic digesters. While there are many kinds of digesters, the biology is basically the same for all. Anaerobic digesters are built...

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

    Science.gov (United States)

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

    2016-01-01

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

  17. Global association between thermophilicity and vancomycin susceptibility in bacteria

    Directory of Open Access Journals (Sweden)

    Chayan eRoy

    2016-03-01

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

  18. Anaerobic treatment of poultry mortality in a temperature-phased leachbed-UASB system.

    Science.gov (United States)

    Chen, Ten-Hong; Huang, Jiun-Lin

    2006-08-01

    Anaerobic digestion has been proposed as an alternative to the conventional disposal methods of burial, incineration, rendering and aerobic composting. A temperature-phased system consisting of one UASB (at 55 degrees C) and three leach-bed reactors (at ambient temperatures) was tested for its efficiencies in treating poultry mortality. The thermophilic UASB was difficult to start-up. It also showed signs of inhibited methanogenesis. Chemical parameters such as long chain fatty acids, volatile fatty acids and ammonia concentrations were all very high for the thermophilic UASB. Lowering its temperature to 35 degrees C enhanced its stability and improved its performances. Lowering the pH of the 55 degrees C UASB also improved its chemical oxygen demand (COD) reduction efficiency as well as its methane production rate. The results were compared to that of another similar system where the UASB reactor was maintained at 35 degrees C instead of at 55 degrees C.

  19. The genes coding for the hsp70(dnaK) molecular chaperone machine occur in the moderate thermophilic archaeon Methanosarcina thermophila TM-1

    DEFF Research Database (Denmark)

    Hofman-Bang, H Jacob Peider; Lange, Marianne; Ahring, Birgitte Kiær

    1999-01-01

    The hsp70 (dnaK) locus of the moderate thermophilic archaeon Methanosarcina thermophila TM-1 was cloned, sequenced, and tested in vitro to measure gene induction by heat and ammonia, i.e., stressors pertinent to the biotechnological ecosystem of this methanogen that plays a key role in anaerobic......-negative bacteria - first described in the S-6 molecule and later found to be present in all homologs from archaea and Gram positives. The genes responded to a temperature elevation in a manner that demonstrated that they are heat-shock genes, functionally active in vivo. Ammonia also induced a heat-shock type...

  20. Nitrogen in the Process of Waste Activated Sludge Anaerobic Digestion

    Directory of Open Access Journals (Sweden)

    Suschka Jan

    2014-07-01

    Full Text Available Primary or secondary sewage sludge in medium and large WWTP are most often processed by anaerobic digestion, as a method of conditioning, sludge quantity minimization and biogas production. With the aim to achieve the best results of sludge processing several modifications of technologies were suggested, investigated and introduced in the full technical scale. Various sludge pretreatment technologies before anaerobic treatment have been widely investigated and partially introduced. Obviously, there are always some limitations and some negative side effects. Selected aspects have been presented and discussed. The problem of nitrogen has been highlighted on the basis of the carried out investigations. The single and two step - mesophilic and thermophilic - anaerobic waste activated sludge digestion processes, preceded by preliminary hydrolysis were investigated. The aim of lab-scale experiments was pre-treatment of the sludge by means of low intensive alkaline and hydrodynamic disintegration. Depending on the pretreatment technologies and the digestion temperature large ammonia concentrations, up to 1800 mg NH4/dm3 have been measured. Return of the sludge liquor to the main sewage treatment line means additional nitrogen removal costs. Possible solutions are discussed.

  1. Anaerobic carboxydotrophic bacteria in geothermal springs identified using stable isotope probing

    Directory of Open Access Journals (Sweden)

    Allyson Lee Brady

    2015-09-01

    Full Text Available Carbon monoxide (CO is a potential energy and carbon source for thermophilic bacteria in geothermal environments. Geothermal sites ranging in temperature from 45–65°C were investigated for the presence and activity of anaerobic CO-oxidizing bacteria. Anaerobic CO oxidation potentials were measured at up to 48.9 µmoles CO day-1 g (wet weight-1 within 5 selected sites. Active anaerobic carboxydotrophic bacteria were identified using 13CO DNA stable isotope probing (SIP combined with pyrosequencing of 16S rRNA genes amplified from labeled DNA. Bacterial communities identified in heavy DNA fractions were predominated by Firmicutes, which comprised up to 95% of all sequences in 13CO incubations. The predominant bacteria that assimilated 13C derived from CO were closely related (>98% to genera of known carboxydotrophs including Thermincola, Desulfotomaculum, Thermolithobacter and Carboxydocella, although a few species with lower similarity to known bacteria were also found that may represent previously unconfirmed CO-oxidizers. While the distribution was variable, many of the same OTUs were identified across sample sites from different temperature regimes. These results show that bacteria capable of using CO as a carbon source are common in geothermal springs, and that thermophilic carboxydotrophs are probably already quite well known from cultivation studies.

  2. Simplified mechanistic model for the two-stage anaerobic degradation of sewage sludge.

    Science.gov (United States)

    Donoso-Bravo, Andrés; Pérez-Elvira, Sara; Fdz-Polanco, Fernando

    2015-01-01

    Two-phase anaerobic systems are being increasingly implemented for the treatment of both sewage sludge and organic fraction of municipal solid waste. Despite the good amount of mathematical models in anaerobic digestion, few have been applied in two-phase systems. In this study, a three-reaction mechanistic model has been developed, implemented and validated by using experimental data from a long-term anaerobic two-phase (TPAD) digester treating sewage sludge. A sensitivity analysis shows that the most influential parameters of the model are the ones related to the hydrolysis reaction and the activity of methanogens in the thermophilic reactor. The calibration procedure highlights a noticeable growth rate of the thermophilic methanogens throughout the evaluation period. Overall, all the measured variables are properly predicted by the model during both the calibration and the cross-validation periods. The model's representation of the organic matter behaviour is quite good. The most important disagreements are observed for the biogas production especially during the validation period. The whole application procedure underlines the ability of the model to properly predict the behaviour of this bioprocess. PMID:25400016

  3. Potential of wastewater-treating anaerobic granules for biomethanation of synthesis gas.

    Science.gov (United States)

    Guiot, Serge R; Cimpoia, Ruxandra; Carayon, Gaël

    2011-03-01

    Gasification of biomass produces a mixture of gas (mainly carbon monoxide (CO), carbon dioxide (CO(2)), and hydrogen (H(2))) called synthesis gas, or syngas, by thermal degradation without combustion. Syngas can be used for heat or electricity production by thermochemical processes. This project aims at developing an alternative way to bioupgrade syngas into biogas (mainly methane), via anaerobic fermentation. Nonacclimated industrial granular sludge to be used as reactor inoculum was initially evaluated for mesophilic carboxydotrophic methanogenesis potential in batch tests at 4 and 8 mmol CO/g VSS.d, in the absence and presence of H(2) and CO(2), respectively. Granular sludge was then introduced into a 30 L gas-lift reactor and supplied with CO, to study the production of methane and other metabolites, at different gas dilutions as well as feeding and recirculation rates. A maximal CO conversion efficiency of 75%, which was gas-liquid mass transfer limited, occurred at a CO partial pressure of 0.6 atm combined with a gas recirculation ratio of 20:1. The anaerobic granule potential for methanogenesis from CO was likely hydrogenotrophic, combined with CO-dependent H(2) formation, either under mesophilic or thermophilic conditions. Thermophilic conditions provide the anaerobic granules with a CO-bioconversion potential significantly larger (5-fold) than under mesophilic conditions, so long as the gas-liquid transfer is alleviated.

  4. A novel ecological role of the Firmicutes identified in thermophilic microbial fuel cells.

    Science.gov (United States)

    Wrighton, Kelly C; Agbo, Peter; Warnecke, Falk; Weber, Karrie A; Brodie, Eoin L; DeSantis, Todd Z; Hugenholtz, Philip; Andersen, Gary L; Coates, John D

    2008-11-01

    Significant effort is currently focused on microbial fuel cells (MFCs) as a source of renewable energy. Most studies concentrate on operation at mesophilic temperatures. However, anaerobic digestion studies have reported on the superiority of thermophilic operation and demonstrated a net energy gain in terms of methane yield. As such, our studies focused on MFC operation and microbiology at 55 degrees C. Over a 100-day operation, these MFCs were stable and achieved a power density of 37 mW m(-2) with a coulombic efficiency of 89%. To infer activity and taxonomic identity of dominant members of the electricity-producing community, we performed phylogenetic microarray and clone library analysis with small subunit ribosomal RNA (16S rRNA) and ribosomal RNA gene (16S rDNA). The results illustrated the dominance (80% of clone library sequences) of the Firmicutes in electricity production. Similarly, rRNA sequences from Firmicutes accounted for 50% of those taxa that increased in relative abundance from current-producing MFCs, implying their functional role in current production. We complemented these analyses by isolating the first organisms from a thermophilic MFC. One of the isolates, a Firmicutes Thermincola sp. strain JR, not only produced more current than known organisms (0.42 mA) in an H-cell system but also represented the first demonstration of direct anode reduction by a member of this phylum. Our research illustrates the importance of using a variety of molecular and culture-based methods to reliably characterize bacterial communities. Consequently, we revealed a previously unidentified functional role for Gram-positive bacteria in MFC current generation. PMID:18769460

  5. Effect of temperature and pH on the kinetics of methane production, organic nitrogen and phosphorus removal in the batch anaerobic digestion process of cattle manure

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, E. [Consultores Ambientales (CONAM), Havanna (Cuba); Borja, R. [Instituto de la Grasa (C.S.I.C.)., Sevilla (Spain); Weiland, P. [Institute of Technology, Federal Research Center of Agriculture (FAL), Braunschweig (Germany); Travieso, L. [Departamento de Estudios sobre Contaminacion Ambiental (DECA-CNIC), Centro Nacional de Investigaciones Cientificas (CNIC), La Habana (Cuba); Martin, A. [Departamento de Ingenieria Quimica, Facultad de Ciencias, Cordoba (Spain)

    2000-03-01

    A study of the effect of temperature and pH on the kinetics of methane production and organic nitrogen and phosphorus degradation in the anaerobic digestion process of cattle manure was carried out. Two laboratory-scale batch completely mixed reactors, operating at 35 C (mesophilic temperature), and other two, operating at 60 C (thermophilic temperature) were used. For each temperature selected, the influent pH values were 7.6 (initial pH of the waste used) and 7.0. The apparent kinetic constants of the biomethanization process increased 2.3 times when the initial pH of the influent was increased from 7.0 to 7.6 at mesophilic temperature. The values found at thermophilic temperature were similar. The kinetic constants of methane production decreased 2.6 and 7.2 times when the operating temperature increased from 35 C to 60 C for the experiments carried out at initial pH of 7.0 and 7.6, respectively. The methane yield coefficient (l CH{sub 4} STP/g VS removed) also decreased when the temperature increased from 35 C to 60 C for the two initial pH values studied. This behaviour agreed with the major inhibition level observed at thermophilic temperature as a result of the higher organic nitrogen removal and ammonia nitrogen production observed at 60 C. Specifically, the specific rate constants for organic nitrogen removal and ammonia nitrogen production increased 3.6 and 12 times when the temperature was increased from 35 C to 60 C for the experiments carried out at initial pH values of 7.0 and 7.6, respectively. In the same way, the values of the kinetic constant for phosphorus removal were 44% and 80% higher than those obtained at 35 C for the two initial pH values above-mentioned, respectively. Finally, the experimental values of organic nitrogen and phosphorus concentrations were reproduced with deviations equal to or less than 10% and 15% in every case, respectively. (orig.)

  6. Dynamics of the anaerobic process: Effects of volatile fatty acids

    DEFF Research Database (Denmark)

    Pind, Peter Frode; Angelidaki, Irini; Ahring, Birgitte Kiær

    2003-01-01

    both CH4 yield, pH, and gas production and that a unique reaction pattern was seen for the higher VFAs as a result of these pulses. In this study, two thermophilic laboratory reactors were equipped with a novel VFA-sensor for monitoring specific VFAs online. Pulses of VFAs were shown to have a positive......A complex and fast dynamic response of the anaerobic biogas system was observed when the system was subjected to pulses of volatile fatty acids (VFAs). It was shown that a pulse of specific VFAs into a well-functioning continuous stirred tank reactor (CSTR) system operating on cow manure affected...... or inhibition was shown for the degradation of all VFAs tested. Based on the results, it was concluded that measurements of all specific VFAs are important for control purposes and increase and decrease in a specific VFA should always be evaluated in close relationship to the conversion of other VFAs...

  7. 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.

  8. 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

    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......% v/v, which is the concentration required in practice for economically efficient product recovery. For all ethanol concentrations tested, relatively high and stable ethanol yields (0.40 - 0.42 g/g) were seen. The strain demonstrated a remarkable, ethanol tolerance, which is the second highest...

  9. Kinetics of thermophilic, anaerobic oxidation of straight and branched chain butyrate and valerate

    DEFF Research Database (Denmark)

    Batstone, Damien J.; Pind, Peter Frode; Angelidaki, Irini

    2003-01-01

    in leucine (which produces i-valerate), and the modified model structure and stoichiometry as proposed here should be used. This requires no additional kinetic parameters and one additional dynamic concentration state variable (i-valerate) in addition to the variables in the base model. (C) 2003 Wiley...

  10. Effects of mixing on methane production during thermophilic anaerobic digestion of manure

    DEFF Research Database (Denmark)

    Kaparaju, Prasad Laxmi-Narasimha; Buendia, Inmaculada M.; Ellegaard, Lars;

    2008-01-01

    /feeding) on methane production was investigated in three lab-scale continuously stirred tank reactors. On comparison to continuous mixing, intermittent and minimal mixing strategies improved methane productions by 1.3% and 12.5%, respectively. Pilot-scale studies also supported the lab-scale results with an average 7...

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

    OpenAIRE

    I Irvan; Bambang Trisakti; Vivian Wongistani; Yoshimasa Tomiuchi

    2012-01-01

    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 resea...

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

    DEFF Research Database (Denmark)

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

    1995-01-01

    and ethanol occurred as minor fermentation products. Only a restricted number of carbon sources (cellulose, xylan, starch, pectin, cellobiose, xylose, maltose and lactose) were used as substrates. During growth on Avicel, the bacterium produced free cellulases with carboxymethylcellulase and avicelase...

  13. Cloning, expression and characterization of glycoside hydrolases from the thermophilic cellulolytic anaerobic bacterium Caldicellulosiruptor kristjanssonii

    OpenAIRE

    Skalman, Lars Nygård

    2010-01-01

    Lignocellulosic biomass has great potential as a substrate for ethanol production as it is a renewable and rather abundant energy source. However, the rigid and complex structure of lignocellulose is a major bottleneck preventing the development of cost-effective production methods. By the use of thermostable cellulolytic enzymes, hydrolysis of cellulose and fermentation of glucose to ethanol could be performed at high temperatures and this would lower the production cost of ethanol significa...

  14. Effects of volatile fatty acids on a thermophilic anaerobic hydrogen fermentation process degrading peptone.

    Science.gov (United States)

    Cheng, S S; Chang, S M; Chen, S T

    2002-01-01

    Hydrogen fermentation using glucose as a single substrate caused abrupt pH drops and the gradual losses of hydrogen producers, which in turn led to system failure. In this study the use of a proteinaceous substrate, peptone, avoided the abrupt pH drops in the reactive system and allowed for further exploration of volatile fatty acids (VFAs) and pH effects on the hydrogen fermentation process. Our results showed that: (1) during the hydrogen fermentation tests, the abrupt pH drops were avoided thus system stability increased due to the production of ammonia from the peptone fermented, (2) pH control was not necessary and the addition of acetate to the process had little effect on the hydrogen fermentation process, (3) at the extreme pHs the addition of acetate either lengthened the lag phase (pH hydrogen production rate (pH > or = 8), and both situations were not desired, and (4) high VFA content in the system sped up the consumption of hydrogen gas. Results of this study suggested that the hydrogen fermentation using the protein-containing substances as substrate was beneficial in maintaining the system pH. As long as the pH was maintained around 6-8, system inhibition due to VFAs accumulation was minimized. Thus, the optimal operation of a hydrogen fermentation process would be achievable via the control of substrate composition at a certain carbohydrate-to-protein ratio.

  15. Fermentative hydrogen production from hydrolyzed cellulosic feedstock prepared with a thermophilic anaerobic bacterial isolate

    Energy Technology Data Exchange (ETDEWEB)

    Lo, Yung Chung [Department of Chemical Engineering, National Cheng Kung University, No. 1 University Road, Tainan 701 (China); Huang, Chi-Yu.; Fu, Tzu-Ning [Department of Environmental Engineering and Science, Tunghai University, Taichung 407 (China); Chen, Chun-Yen; Chang, Jo-Shu [Department of Chemical Engineering, National Cheng Kung University, No. 1 University Road, Tainan 701 (China); Sustainable Environment Research Center, National Cheng Kung University, Tainan (China)

    2009-08-15

    Hydrogen gas was produced via dark fermentation from natural cellulosic materials and {alpha}-cellulose via a two-step process, in which the cellulosic substrates were first hydrolyzed by an isolated cellulolytic bacterium Clostridium strain TCW1, and the resulting hydrolysates were then used as substrate for fermentative H{sub 2} production. The TCW1 strain was able to hydrolyze all the cellulosic materials examined to produce reducing sugars (RS), attaining the best reducing sugar production yield of 0.65 g reducing sugar/g substrate from hydrolysis of {alpha}-cellulose. The hydrolysates of those cellulosic materials were successfully converted to H{sub 2} via dark fermentation using seven H{sub 2}-producing bacterial isolates. The bioH{sub 2} production performance was highly dependent on the type of cellulosic feedstock used, the initial reducing sugar concentration (C{sub RS,o}) (ranging from 0.7 to 4.5 mg/l), as well as the composition of sugar and soluble metabolites present in the cellulosic hydrolysates. It was found that Clostridium butyricum CGS5 displayed the highest H{sub 2}-producing efficiency with a cumulative H{sub 2} production of 270 ml/l from {alpha}-cellulose hydrolysate (C{sub RS,o} = 4.52 mg/l) and a H{sub 2} yield of 7.40 mmol/g RS (or 6.66 mmol/g substrate) from napier grass hydrolysate (C{sub RS,o} = 1.22 g/l). (author)

  16. Hydrogen and methane production from desugared molasses using a two‐stage thermophilic anaerobic process

    DEFF Research Database (Denmark)

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

    2013-01-01

    of 3380 mL CH4/day/L, corresponding to a yield of 239 mL CH4/g VS. Aceticlastic Methanosarcina mazei was the dominant methanogen in the methanogenesis stage. This work demonstrates that biohydrogen production can be very efficiently coupled with a subsequent step of methane production using desugared...

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

    OpenAIRE

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

    2015-01-01

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

  18. 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.

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

    OpenAIRE

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

    1994-01-01

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

  20. Lignocellulose-derived thin stillage composition and efficient biological treatment with a high-rate hybrid anaerobic bioreactor system

    KAUST Repository

    Oosterkamp, Margreet J.

    2016-06-06

    Background This study aims to chemically characterize thin stillage derived from lignocellulosic biomass distillation residues in terms of organic strength, nutrient, and mineral content. The feasibility of performing anaerobic digestion on these stillages at mesophilic (40 °C) and thermophilic (55 °C) temperatures to produce methane was demonstrated. The microbial communities involved were further characterized. Results Energy and sugar cane stillage have a high chemical oxygen demand (COD of 43 and 30 g/L, respectively) and low pH (pH 4.3). Furthermore, the acetate concentration in sugar cane stillage was high (45 mM) but was not detected in energy cane stillage. There was also a high amount of lactate in both types of stillage (35–37 mM). The amount of sugars was 200 times higher in energy cane stillage compared to sugar cane stillage. Although there was a high concentration of sulfate (18 and 23 mM in sugar and energy cane stillage, respectively), both thin stillages were efficiently digested anaerobically with high COD removal under mesophilic and thermophilic temperature conditions and with an organic loading rate of 15–21 g COD/L/d. The methane production rate was 0.2 L/g COD, with a methane percentage of 60 and 64, and 92 and 94 % soluble COD removed, respectively, by the mesophilic and thermophilic reactors. Although both treatment processes were equally efficient, there were different microbial communities involved possibly arising from the differences in the composition of energy cane and sugar cane stillage. There was more acetic acid in sugar cane stillage which may have promoted the occurrence of aceticlastic methanogens to perform a direct conversion of acetate to methane in reactors treating sugar cane stillage. Conclusions Results showed that thin stillage contains easily degradable compounds suitable for anaerobic digestion and that hybrid reactors can efficiently convert thin stillage to methane under mesophilic and thermophilic conditions

  1. Survival of Antibiotic Resistant Bacteria and Horizontal Gene Transfer Control Antibiotic Resistance Gene Content in Anaerobic Digesters

    Science.gov (United States)

    Miller, Jennifer H.; Novak, John T.; Knocke, William R.; Pruden, Amy

    2016-01-01

    Understanding fate of antibiotic resistant bacteria (ARB) vs. their antibiotic resistance genes (ARGs) during wastewater sludge treatment is critical in order to reduce the spread of antibiotic resistance through process optimization. Here, we spiked high concentrations of tetracycline-resistant bacteria, isolated from mesophilic (Iso M1-1—a Pseudomonas sp.) and thermophilic (Iso T10—a Bacillus sp.) anaerobic digested sludge, into batch digesters and monitored their fate by plate counts and quantitative polymerase chain reaction (QPCR) of their corresponding tetracycline ARGs. In batch studies, spiked ARB plate counts returned to baseline (thermophilic) or 1-log above baseline (mesophilic) while levels of the ARG present in the spiked isolate [tet(G)] remained high in mesophilic batch reactors. To compare results under semi-continuous flow conditions with natural influent variation, tet(O), tet(W), and sul1 ARGs, along with the intI1 integrase gene, were monitored over a 9-month period in the raw feed sludge and effluent sludge of lab-scale thermophilic and mesophilic anaerobic digesters. sul1 and intI1 in mesophilic and thermophilic digesters correlated positively (Spearman rho = 0.457–0.829, P < 0.05) with the raw feed sludge. There was no correlation in tet(O) or tet(W) ratios in raw sludge and mesophilic digested sludge or thermophilic digested sludge (Spearman rho = 0.130–0.486, P = 0.075–0.612). However, in the thermophilic digester, the tet(O) and tet(W) ratios remained consistently low over the entire monitoring period. We conclude that the influent sludge microbial composition can influence the ARG content of a digester, apparently as a result of differential survival or death of ARBs or horizontal gene transfer of genes between raw sludge ARBs and the digester microbial community. Notably, mesophilic digestion was more susceptible to ARG intrusion than thermophilic digestion, which may be attributed to a higher rate of ARB survival and

  2. Survival of Antibiotic Resistant Bacteria and Horizontal Gene Transfer Control Antibiotic Resistance Gene Content in Anaerobic Digesters.

    Science.gov (United States)

    Miller, Jennifer H; Novak, John T; Knocke, William R; Pruden, Amy

    2016-01-01

    Understanding fate of antibiotic resistant bacteria (ARB) vs. their antibiotic resistance genes (ARGs) during wastewater sludge treatment is critical in order to reduce the spread of antibiotic resistance through process optimization. Here, we spiked high concentrations of tetracycline-resistant bacteria, isolated from mesophilic (Iso M1-1-a Pseudomonas sp.) and thermophilic (Iso T10-a Bacillus sp.) anaerobic digested sludge, into batch digesters and monitored their fate by plate counts and quantitative polymerase chain reaction (QPCR) of their corresponding tetracycline ARGs. In batch studies, spiked ARB plate counts returned to baseline (thermophilic) or 1-log above baseline (mesophilic) while levels of the ARG present in the spiked isolate [tet(G)] remained high in mesophilic batch reactors. To compare results under semi-continuous flow conditions with natural influent variation, tet(O), tet(W), and sul1 ARGs, along with the intI1 integrase gene, were monitored over a 9-month period in the raw feed sludge and effluent sludge of lab-scale thermophilic and mesophilic anaerobic digesters. sul1 and intI1 in mesophilic and thermophilic digesters correlated positively (Spearman rho = 0.457-0.829, P < 0.05) with the raw feed sludge. There was no correlation in tet(O) or tet(W) ratios in raw sludge and mesophilic digested sludge or thermophilic digested sludge (Spearman rho = 0.130-0.486, P = 0.075-0.612). However, in the thermophilic digester, the tet(O) and tet(W) ratios remained consistently low over the entire monitoring period. We conclude that the influent sludge microbial composition can influence the ARG content of a digester, apparently as a result of differential survival or death of ARBs or horizontal gene transfer of genes between raw sludge ARBs and the digester microbial community. Notably, mesophilic digestion was more susceptible to ARG intrusion than thermophilic digestion, which may be attributed to a higher rate of ARB survival and/or horizontal gene

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-02-15

    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

  4. Yield and Quality of Biogas from Anaerobic Fermentation of Grass

    OpenAIRE

    Poláček, Jan

    2014-01-01

    Biogas is generally considered as a renewable source of energy. In fact, however, it is biodegradable organic material, that makes this source of energy renewable. Biogas is, then, the final product of anaerobic fermentation of these materials. Because energetically the most valuable component of biogas is methane (CH4) its relative volume stands as the measure of biogas quality. The process of anaerobic fermentation was characterized in the first part of this thesis. Organic materials ar...

  5. Anaerobic bacteria in otitis media.

    Science.gov (United States)

    Fulghum, R S; Daniel, H J; Yarborough, J G

    1977-01-01

    Anaerobic bacteria, Peptostrepotococcus intermedius and Propionibacterium acnes, were found in mixed culture specimens from four to ten tested cases of chronic secretory otitis media. These anaerobic bacteria were in a mixed infection flora with aerobic bacteria most often Staphylococcus epidermidis and Cornybacterium sp. which do not fit any established species. The findings of anaerobic bacteria in otitis media is consistent with the sporadic report of the involvement of anaerobic bacteria in otitis media in the literature since 1898.

  6. Anaerobic digestion in combination with 2nd generation ethanol production for maximizing biofuels yield from lignocellulosic biomass – testing in an integrated pilot-scale biorefinery plant

    DEFF Research Database (Denmark)

    Uellendahl, Hinrich; Ahring, Birgitte Kiær

    An integrated biorefinery concept for 2nd generation bioethanol production together with biogas production from the fermentation effluent was tested in pilot-scale. The pilot plant comprised pretreatment, enzymatic hydrolysis, hexose and pentose fermentation into ethanol and anaerobic digestion...... for mesophilic than for thermophilic operation. The effluent from the ethanol fermentation showed no signs of toxicity to the anaerobic microorganisms. Implementation of the biogas production from the fermentation effluent accounted for about 30% higher biofuels yield in the biorefinery compared to a system...

  7. Bio-hythane production from food waste by dark fermentation coupled with anaerobic digestion process: A long-term pilot scale experience

    OpenAIRE

    Cavinato, Cristina; Giuliano, Antonio; Bolzonella, David; Pavan, Paolo; Cecchi, Franco

    2012-01-01

    In this paper are presented the results of the investigation on optimal process operational conditions of thermophilic dark fermentation and anaerobic digestion of food waste, testing a long term run, applying an organic loading rate of 16.3 kgTVS/m3d in the first phase and 4.8 kgTVS/m3d in the second phase. The hydraulic retention times were maintained at 3.3 days and 12.6 days, respectively, for the first and second phase. Recirculation of anaerobic digested sludge, after a mild solid separ...

  8. Enhanced coproduction of hydrogen and methane from cornstalks by a three-stage anaerobic fermentation process integrated with alkaline hydrolysis.

    Science.gov (United States)

    Cheng, Xi-Yu; Liu, Chun-Zhao

    2012-01-01

    A three-stage anaerobic fermentation process including H(2) fermentation I, H(2) fermentation II, methane fermentation was developed for the coproduction of hydrogen and methane from cornstalks. Hydrogen production from cornstalks using direct microbial conversion by Clostridium thermocellum 7072 was markedly enhanced in the two-stage thermophilic hydrogen fermentation process integrated with alkaline treatment. The highest total hydrogen yield from cornstalks in the two-stage fermentation process reached 74.4 mL/g-cornstalk. The hydrogen fermentation effluents and alkaline hydrolyzate were further used for methane fermentation by anaerobic granular sludge, and the total methane yield reached 205.8 mL/g-cornstalk. The total energy recovery in the three-stage anaerobic fermentation process integrated with alkaline hydrolysis reached 70.0%.

  9. The role of anaerobic digestion in controlling the release of tetracycline resistance genes and class 1 integrons from municipal wastewater treatment plants.

    Science.gov (United States)

    Ghosh, Sudeshna; Ramsden, Sara J; LaPara, Timothy M

    2009-09-01

    In this study, the abilities of two anaerobic digestion processes used for sewage sludge stabilization were compared for their ability to reduce the quantities of three genes that encode resistance to tetracycline (tet(A), tet(O), and tet(X)) and one gene involved with integrons (intI1). A two-stage, thermophilic/mesophilic digestion process always resulted in significant decreases in the quantities of tet(X) and intI1, less frequently in decreases of tet(O), and no net decrease in tet(A). The thermophilic stage was primarily responsible for reducing the quantities of these genes, while the subsequent mesophilic stage sometimes caused a rebound in their quantities. In contrast, a conventional anaerobic digestion process rarely caused a significant decrease in the quantities of any of these genes, with significant increases occurring more frequently. Our results demonstrate that anaerobic thermophilic treatment was more efficient in reducing quantities of genes associated with the spread of antibiotic resistance compared to mesophilic digestion. PMID:19597810

  10. THERMOPHILE ENDOSPORES HAVE RESPONSIVE EXOSPORIUM FOR ATTACHMENT

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-08-01

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

  11. The anaerobic digestion process

    Energy Technology Data Exchange (ETDEWEB)

    Rivard, C.J. [National Renewable Energy Lab., Golden, CO (United States); Boone, D.R. [Oregon Graduate Inst., Portland, OR (United States)

    1996-01-01

    The microbial process of converting organic matter into methane and carbon dioxide is so complex that anaerobic digesters have long been treated as {open_quotes}black boxes.{close_quotes} Research into this process during the past few decades has gradually unraveled this complexity, but many questions remain. The major biochemical reactions for forming methane by methanogens are largely understood, and evolutionary studies indicate that these microbes are as different from bacteria as they are from plants and animals. In anaerobic digesters, methanogens are at the terminus of a metabolic web, in which the reactions of myriads of other microbes produce a very limited range of compounds - mainly acetate, hydrogen, and formate - on which the methanogens grow and from which they form methane. {open_quotes}Interspecies hydrogen-transfer{close_quotes} and {open_quotes}interspecies formate-transfer{close_quotes} are major mechanisms by which methanogens obtain their substrates and by which volatile fatty acids are degraded. Present understanding of these reactions and other complex interactions among the bacteria involved in anaerobic digestion is only now to the point where anaerobic digesters need no longer be treated as black boxes.

  12. Anaerobic biological treatment

    International Nuclear Information System (INIS)

    The Enso-Fenox process has been very successfully used to remove chlorinated phenolic compounds from pulp bleaching effluents. It is a two-stage anaerobic/aerobic process consisting of a nonmethanogenic anaerobic fluidized bed followed by a trickling filter. Studies have been conducted on reductive dechlorination of chlorinated aromatic compounds under anaerobic conditions with chlorinated phenols as the sole carbon and energy source. Approximately 40% of the added chlorophenols was converted to CH4 and CO2. Substrate loading rates were 20 mg/L/d at hydraulic detention times of 2-4 days with 90% substrate conversion efficiency. Reductive dechlorination of mono, di-, tri-, and pentachlorophenols has been demonstrated in anaerobic sewage sludge. The following constituents were tested in the laboratory at their approximate concentrations in coal conversion wastewater (CCWW) and were anaerobically degraded in serum bottles: 1,000 mg/L phenol; 500 mg/L resorcinol; 1,000 mg/L benzoic acid; 500 mg/L p-cresol; 200 mg/L pyridine; 2,000 mg/L benzoic acid; 250 mg/L 40 methylcatechol; 500 mg/L 4-ethylpyridine; and 2,000 mg/L hexanoic acid. A petrochemical may initially exhibit toxicity to an unacclimated population of methane-fermenting bacteria, but with acclimation the toxicity may be greatly reduced or disappear. In addition, the microorganisms may develop the capacity to actually degrade compounds which showed initial toxicity. Since biomass digestion requires a complete consortium of bacteria, it is relevant to study the effect of a given process as well as to individual steps within the process. A toxicant can inhibit the rate-limiting step and/or change the step that is rate-limiting. Both manifestations of toxicity can severely affect the overall process

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

    Science.gov (United States)

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

    2012-11-01

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

  14. Anaerobic Treatment of Municipal Solid Waste and Sludge for Energy Production and Recycling of Nutrients

    Science.gov (United States)

    Leinonen, S.

    This volume contains 18 papers presented at a Nordic workshop dealing with application of anaerobic decomposition processes on various types of organic wastes, held at the Siikasalmi Research and Experimental Station of the University of Joensuu on 1-2 Oct. 1992. Subject coverage of the presentations extends from the biochemical and microbiological principles of organic waste processing to descriptions and practical experiences of various types of treatment plants. The theoretical and experimental papers include studies on anaerobic and thermophilic degradation processes, methanogenesis, effects of hydrogen, treatment of chlorinated and phenolic compounds, and process modeling, while the practical examples range from treatment of various types of municipal, industrial, and mining wastes to agricultural and fish farm effluents. The papers provide technical descriptions of several biogas plants in operation. Geographically, the presentations span the Nordic and Baltic countries.

  15. Optimising the anaerobic co-digestion of urban organic waste using dynamic bioconversion mathematical modelling

    DEFF Research Database (Denmark)

    Fitamo, Temesgen Mathewos; Boldrin, Alessio; Dorini, G.;

    2016-01-01

    strategies for controlling and optimising the co-digestion process. The model parameters were maintained in the same way as the original dynamic bioconversion model, albeit with minor adjustments, to simulate the co-digestion of food and garden waste with mixed sludge from a wastewater treatment plant......Mathematical anaerobic bioconversion models are often used as a convenient way to simulate the conversion of organic materials to biogas. The aim of the study was to apply a mathematical model for simulating the anaerobic co-digestion of various types of urban organic waste, in order to develop...... in a continuously stirred tank reactor. The model's outputs were validated with experimental results obtained in thermophilic conditions, with mixed sludge as a single substrate and urban organic waste as a co-substrate at hydraulic retention times of 30, 20, 15 and 10 days. The predicted performance parameter...

  16. [Influence of Temperature on the Anaerobic Packed Bed Reactor Performance and Methanogenic Community].

    Science.gov (United States)

    Xie, Hai-ying; Wang, Xin; Li, Mu-yuan; Yan, Xu-you; Igarashi, Yasuo; Luo, Feng

    2015-11-01

    This study aimed to analyze the effect of temperature on performance and microbial community structure of an anaerobic packed bed reactor (APBR). The temperature was increased step-wise from room temperature (22 degrees C ± 1 degrees C) to psychrophilic (15 degrees C ± 1 degrees C), mesophilic (37 degrees C ± 1 degrees C) and thermophilic (55 degrees C ± 1 degrees C). The results showed that, in the temperature changing process, the higher the temperature of APBR was, the higher COD removal rate and daily gas production were. After temperature changed to psychrophilic, mesophilic and thermophilic, COD removal rate and daily gas production were 25%, 45%, 60% and 2.3 L x d(-1), 4.0 L x d(-1), 8.5 L x d(-1) respectively. However, there was no significant change in biogas composition (-60%). A sudden temperature change caused a simultaneous increase in the concentration of volatile fatty acids (VFA), which had been fluctuating. Using 16S rRNA gene clone library screening, Euryarchaeota was commonly found, including important methanogens: MBT (Methanobacteriales), Mst (Methanosaetaceae) , Msc (Methanosarcinaceae) and MMB (Methanomicrobiales), as well as thermophilic bacteria and few spring Archaea. However, the diversity of methanogenic groups was reduced, especially at mesophilic. The results of quantitative PCR showed that the 16S rRNA gene concentrations of Mst, MMB and Msc were reduced by temperature changes. Although the relative proportion of every kind of methanogen was significantly affected, Mst was the dominant methanogen. PMID:26911011

  17. Molecular phylogenetical studies of the thermophilic spore-forming desulfotomaculum isolated from oil-field

    Institute of Scientific and Technical Information of China (English)

    Chen Wu; Li Chunyan; Xiang Fu; Yu Longjiang

    2005-01-01

    A novel thermophilic and heterotrophic sulfate-reducing bacteria, strain CW-03, was isolated from crude oil well whose depth was 3.2 kilometer. The bacterium was strictly anaerobic; it does not endure acid and itsmaximum surviving temperature was 70℃. Many short chain organic compounds can be utilized as electron donors, which were acetate, formate, lactate, propionate, pyruvate, butyrate, succinate, malate, fumarate,valerate, caproate, heptanoate, octanoate, decanoate, tridecanoate, pentadecanoate, palmitate, heptadecanoate or ethanol, while sulfate and sulfite were used as electron acceptors. The following substrates were not utilized: benzoate undecanoate, dodecanoate, tetradecane, propanol, butanol, H2+CO2 (80/20%; v/v) and acetate (1mM)+ H2. When lactate was used as electron donors, sulfite and thiosulfate, but not sulfer and nitrate, can be used as electron acceptors. Strain CW-03 was motile, curved rod, Gram-positive, pole flagellum and spore-forming. On the basis of 16S rRNA sequence alignment (accession numbers: AY703032), CW-03 should be included in the genus Desulfotomaculum with BIAST analysis on line. However, some of its physiology and multiple sequence alignments were different from other members of this genus. Therefore, CW-03 should be recognized as a new species, for which we propose the name Desulfotomaculum chinamiddle (Bacteria, Firmicutes, Clostridia, Clostridiales, Peptococcaceae).

  18. 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.

  19. Encapsulated in silica: genome, proteome and physiology of the thermophilic bacterium Anoxybacillus flavithermus

    Energy Technology Data Exchange (ETDEWEB)

    Saw, Jimmy H [Los Alamos National Laboratory; Mountain, Bruce W [NEW ZEALAND; Feng, Lu [NANKAI UNIV; Omelchenko, Marina V [NCBI/NLM/NIH; Hou, Shaobin [UNIV OF HAWAII; Saito, Jennifer A [UNIV OF HAWAII; Stott, Matthew B [NEW ZEALAND; Li, Dan [NANKAI UNIV; Zhao, Guang [NANKAI UNIV; Wu, Junli [NANKAI UNIV; Galperin, Michael Y [NCBI/NLM/NIH; Koonin, Eugene V [NCBI/NLM/NIH; Makarova, Kira S [NCBI/NLM/NIH; Wolf, Yuri I [NCBI/NLM/NIH; Rigden, Daniel J [UNIV OF LIVERPOOL; Dunfield, Peter F [UNIV OF CALGARY; Wang, Lei [NANKAI UNIV; Alam, Maqsudul [UNIV OF HAWAII

    2008-01-01

    Gram-positive bacteria of the genus Anoxybacillus have been found in diverse thermophilic habitats, such as geothermal hot springs and manure, and in processed foods such as gelatin and milk powder. Anoxybacillus flavithermus is a facultatively anaerobic bacterium found in super-saturated silica solutions and in opaline silica sinter. The ability of A. flavithermus to grow in super-saturated silica solutions makes it an ideal subject to study the processes of sinter formation, which might be similar to the biomineralization processes that occurred at the dawn of life. We report here the complete genome sequence of A. flavithermus strain WK1, isolated from the waste water drain at the Wairakei geothermal power station in New Zealand. It consists of a single chromosome of 2,846,746 base pairs and is predicted to encode 2,863 proteins. In silico genome analysis identified several enzymes that could be involved in silica adaptation and biofilm formation, and their predicted functions were experimentally validated in vitro. Proteomic analysis confirmed the regulation of biofilm-related proteins and crucial enzymes for the synthesis of long-chain polyamines as constituents of silica nanospheres. Microbial fossils preserved in silica and silica sinters are excellent objects for studying ancient life, a new paleobiological frontier. An integrated analysis of the A. flavithermus genome and proteome provides the first glimpse of metabolic adaptation during silicification and sinter formation. Comparative genome analysis suggests an extensive gene loss in the Anoxybacillus/Geobacillus branch after its divergence from other bacilli.

  20. Bench-scale Analysis of Surrogates for Anaerobic Digestion Processes.

    Science.gov (United States)

    Carroll, Zachary S; Long, Sharon C

    2016-05-01

    Frequent monitoring of anaerobic digestion processes for pathogen destruction is both cost and time prohibitive. The use of surrogates to supplement regulatory monitoring may be one solution. To evaluate surrogates, a semi-batch bench-scale anaerobic digester design was tested. Bench-scale reactors were operated under mesophilic (36 °C) and thermophilic (53-55 °C) conditions, with a 15 day solids retention time. Biosolids from different facilities and during different seasons were examined. USEPA regulated pathogens and surrogate organisms were enumerated at different times throughout each experiment. The surrogate organisms included fecal coliforms, E. coli, enterococci, male-specific and somatic coliphages, Clostridium perfringens, and bacterial spores. Male-specific coliphages tested well as a potential surrogate organism for virus inactivation. None of the tested surrogate organisms correlated well with helminth inactivation under the conditions studied. There were statistically significant differences in the inactivation rates between the facilities in this study, but not between seasons. PMID:27131309

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

    NARCIS (Netherlands)

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

    2013-01-01

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

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

    NARCIS (Netherlands)

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

    2013-01-01

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

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

    NARCIS (Netherlands)

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

    1993-01-01

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

  4. Kinetic comparisons of mesophilic and thermophilic aerobic biomass

    NARCIS (Netherlands)

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

    2003-01-01

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

  5. Sequential anaerobic-adsorption treatment of chemical industry wastewater.

    Science.gov (United States)

    Daga, Kailash; Pallavi, V; Patel, Dharmendra

    2011-10-01

    Treatment technologies needed to reduce the pollutant load of chemical industry effluent have been found to involve exorbitantly high costs. The present investigation aimed to treat the wastewater from chemical industry by cost effective sequential anaerobic-adsorption treatment. Wastewaters from chemical industry that are rich in biodegradable organics are tested for anaerobic treatability. The efficiency of anaerobic reactor is relatively lower 79.3%, and therefore post treatment of effluent was done by adsorption using Poly vinyl alcohol coated Datura stramonium (PVAC-DS) as an adsorbent. An overall COD removal of 93.8 % was achieved after sequential Anaerobic-Adsorption treatment, which lead to a better final effluent and a more economical treatment system.

  6. Characteristic features in the structure and collagen-binding ability of a thermophilic collagenolytic protease from the thermophile Geobacillus collagenovorans MO-1.

    Science.gov (United States)

    Itoi, Yuichi; Horinaka, Mano; Tsujimoto, Yoshiyuki; Matsui, Hiroshi; Watanabe, Kunihiko

    2006-09-01

    A collagen-degrading thermophile, Geobacillus collagenovorans MO-1, extracellularly produces a collagenolytic protease with a large molecular mass. Complete nucleotide sequencing of this gene after gene cloning revealed that the collagenolytic protease is a member of the subtilisin family of serine proteases and consists of a signal sequence for secretion, a prosequence for maturation, a catalytic region, 14 direct repeats of 20 amino acids at the C terminus, and a region with unknown function intervening between the catalytic region and the numerous repeats. Since the unusual repeats are most likely to be cleaved in the secreted form of the enzyme, the intervening region was investigated to determine whether it participates in collagen binding to facilitate collagen degradation. It was found that the mature collagenolytic protease containing the intervening region at the C terminus bound collagen but not the other insoluble proteins, elastin and keratin. Furthermore, the intervening region fused with glutathione S-transferase showed a collagen-binding ability comparable to that of the mature collagenolytic protease. The collagen-binding ability was finally attributed to two-thirds of the intervening region which is rich in beta-strands and is approximately 35 kDa in molecular mass. In the collagenolytic protease from strain MO-1, hydrogen bonds most likely predominate over the hydrophobic interaction for collagen binding, since a higher concentration of NaCl released collagen from the enzyme surface but a nonionic detergent could not. To the best of our knowledge, this is the first report of a thermophilic collagenolytic protease containing the collagen-binding segment.

  7. Anaerobic digestion of sulfate-acidified cattle slurry: One-stage vs. two-stage.

    Science.gov (United States)

    Moset, Veronica; Ottosen, Lars Ditlev Mørck; Xavier, Cristiane de Almeida Neves; Møller, Henrik Bjarne

    2016-05-15

    Two strategies to include acidified cattle manure (AcCM) in co-digestion with normal cattle manure (CM) are presented in this work. The strategies are a single thermophilic (50 °C) continuous stirred tank reactor (CSTR) anaerobic digestion and a two-step (65 °C + 50 °C) CSTR process. In both strategies, two different inclusion levels of H2SO4-acidified CM (10% and 20%) in co-digestion with normal CM were tested and compared with a control CSTR fed only CM. Important enhancement of methane (CH4) yield and solid reductions were observed in the thermophilic one-step CSTR working with 10% AcCM. However, a higher inclusion level of AcCM (20%) caused volatile fatty acid accumulation in the reactor and a more than 30% reduction in CH4 production. In terms of CH4 production, when 10% of AcCM was co-digested with 90% of CM, the two-step anaerobic co-digestion yielded less than the single step. During the first step of the two-step CSTR process, acidogenesis and a partial sulfate reduction were achieved. However, sulfide stripping between the first and the second step must be promoted in order to advance this technology.

  8. Anaerobic digestion of sulfate-acidified cattle slurry: One-stage vs. two-stage.

    Science.gov (United States)

    Moset, Veronica; Ottosen, Lars Ditlev Mørck; Xavier, Cristiane de Almeida Neves; Møller, Henrik Bjarne

    2016-05-15

    Two strategies to include acidified cattle manure (AcCM) in co-digestion with normal cattle manure (CM) are presented in this work. The strategies are a single thermophilic (50 °C) continuous stirred tank reactor (CSTR) anaerobic digestion and a two-step (65 °C + 50 °C) CSTR process. In both strategies, two different inclusion levels of H2SO4-acidified CM (10% and 20%) in co-digestion with normal CM were tested and compared with a control CSTR fed only CM. Important enhancement of methane (CH4) yield and solid reductions were observed in the thermophilic one-step CSTR working with 10% AcCM. However, a higher inclusion level of AcCM (20%) caused volatile fatty acid accumulation in the reactor and a more than 30% reduction in CH4 production. In terms of CH4 production, when 10% of AcCM was co-digested with 90% of CM, the two-step anaerobic co-digestion yielded less than the single step. During the first step of the two-step CSTR process, acidogenesis and a partial sulfate reduction were achieved. However, sulfide stripping between the first and the second step must be promoted in order to advance this technology. PMID:26985731

  9. Anaerobic azo dye reduction

    OpenAIRE

    Zee, van der, KG Kristoffer

    2002-01-01

    Azo dyes, aromatic moieties linked together by azo (-N=N-) chromophores, represent the largest class of dyes used in textile-processing and other industries. The release of these compounds into the environment is undesirable, not only because of their colour, but also because many azo dyes and their breakdown products are toxic and/or mutagenic to life. To remove azo dyes from wastewater, a biological treatment strategy based on anaerobic reduction of the azo dyes, followed by aerobic transfo...

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

    International Nuclear Information System (INIS)

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

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

    Science.gov (United States)

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

    2014-11-01

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

  12. Nitrogen availability and indirect measurements of greenhouse gas emissions from aerobic and anaerobic biowaste digestates applied to agricultural soils

    International Nuclear Information System (INIS)

    Highlights: • Nitrogen release in digestate-amended soil depends on the digestate type. • Overall N release is modulated by digestate mineral and mineralisable N contents. • Microbial immobilisation does not influence overall release of digestate N in soil. • Digestate physical properties and soil type interact to affect overall N recovery. • High labile C inputs in digestate may promote denitrification in fine-textured soil. - Abstract: Recycling biowaste digestates on agricultural land diverts biodegradable waste from landfill disposal and represents a sustainable source of nutrients and organic matter (OM) to improve soil for crop production. However, the dynamics of nitrogen (N) release from these organic N sources must be determined to optimise their fertiliser value and management. This laboratory incubation experiment examined the effects of digestate type (aerobic and anaerobic), waste type (industrial, agricultural and municipal solid waste or sewage sludge) and soil type (sandy loam, sandy silt loam and silty clay) on N availability in digestate-amended soils and also quantified the extent and significance of the immobilisation of N within the soil microbial biomass, as a possible regulatory mechanism of N release. The digestate types examined included: dewatered, anaerobically digested biosolids (DMAD); dewatered, anaerobic mesophilic digestate from the organic fraction of municipal solid waste (DMADMSW); liquid, anaerobic co-digestate of food and animal slurry (LcoMAD) and liquid, thermophilic aerobic digestate of food waste (LTAD). Ammonium chloride (NH4Cl) was included as a reference treatment for mineral N. After 48 days, the final, maximum net recoveries of mineral N relative to the total N (TN) addition in the different digestates and unamended control treatments were in the decreasing order: LcoMAD, 68%; LTAD, 37%, DMAD, 20%; and DMADMSW, 11%. A transient increase in microbial biomass N (MBN) was observed with LTAD application

  13. North Western Spain hot springs are a source of lipolytic enzyme-producing thermophilic microorganisms.

    Science.gov (United States)

    Deive, Francisco J; Alvarez, María S; Sanromán, M Angeles; Longo, Maria A

    2013-02-01

    Several hot springs in Galicia (North Western Spain) have been investigated as potential sources of lipolytic enzyme-producing thermophilic microorganisms. After isolating 12 esterase producing strains, 9 of them were assured to be true lipase producers, and consequently grown in submerged cultures, obtaining high extracellular activities by two of them. Furthermore, a preliminary partial characterization of the crude lipase, obtained by ultrafiltration of the cell-free culture supernatant, was carried out at several pH and temperature values. It is outstanding that several enzymes turned out to be multiextremozymes, since they had their optimum temperature and pH at typical values from thermoalkalophiles. The thermal stability in aqueous solution of the crude enzymes was also assayed, and the influence of some potential enzyme stabilizing compounds was tested. Finally, the viability of the selected microorganisms has been demonstrated at bioreactor scale.

  14. Quantitative risk assessment of human campylobacteriosis associated with thermophilic Campylobacter species in chickens

    DEFF Research Database (Denmark)

    Rosenquist, Hanne; Nielsen, N. L.; Sommer, Helle Mølgaard;

    2003-01-01

    A quantitative risk assessment comprising the elements hazard identification, hazard characterization, exposure assessment, and risk characterization has been prepared to assess the effect of different mitigation strategies on the number of human cases in Denmark associated with thermophilic...... Campylobacter spp. in chickens. To estimate the human exposure to Campylobacter from a chicken meal and the number of human cases associated with this exposure, a mathematical risk model was developed. The model details the spread and transfer of Campylobacter in chickens from slaughter to consumption and the...... covers the transfer of Campylobacter during food handling in private kitchens. The age and sex of consumers were included in this module to introduce variable hygiene levels during food preparation and variable sizes and compositions of meals. Finally, the outcome of the exposure assessment modules was...

  15. Effect of food to microorganism ratio on biohydrogen production from food waste via anaerobic fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Jinming [Department of Biosystems Engineering, Zhejiang University, Hangzhou 310029 (China); Department of Biological and Agricultural Engineering, University of California at Davis, One Shields Avenue, Davis, CA 95616 (United States); Zhang, Ruihong; Sun, Huawei [Department of Biological and Agricultural Engineering, University of California at Davis, One Shields Avenue, Davis, CA 95616 (United States); El-Mashad, Hamed M. [Department of Biological and Agricultural Engineering, University of California at Davis, One Shields Avenue, Davis, CA 95616 (United States); Department of Agricultural Engineering, Mansoura University, El-Mansoura (Egypt); Ying, Yibin [Department of Biosystems Engineering, Zhejiang University, Hangzhou 310029 (China)

    2008-12-15

    The effect of different food to microorganism ratios (F/M) (1-10) on the hydrogen production from the anaerobic batch fermentation of mixed food waste was studied at two temperatures, 35 {+-} 2 C and 50 {+-} 2 C. Anaerobic sludge taken from anaerobic reactors was used as inoculum. It was found that hydrogen was produced mainly during the first 44 h of fermentation. The F/M between 7 and 10 was found to be appropriate for hydrogen production via thermophilic fermentation with the highest yield of 57 ml-H{sub 2}/g VS at an F/M of 7. Under mesophilic conditions, hydrogen was produced at a lower level and in a narrower range of F/Ms, with the highest yield of 39 ml-H{sub 2}/g VS at the F/M of 6. A modified Gompertz equation adequately (R{sup 2} > 0.946) described the cumulative hydrogen production yields. This study provides a novel strategy for controlling the conditions for production of hydrogen from food waste via anaerobic fermentation. (author)

  16. New perspectives in anaerobic digestion

    DEFF Research Database (Denmark)

    van Lier, J.B.; Tilche, A.; Ahring, Birgitte Kiær;

    2001-01-01

    requirements. In fact, most advances were achieved during the last three decades, when high-rate reactor systems were developed and a profound insight was obtained in the microbiology of the anaerobic communities. This insight led to a better understanding of anaerobic treatment and, subsequently, to a broader......The IWA specialised group on anaerobic digestion (AD) is one of the oldest working groups of the former IAWQ organisation. Despite the fact that anaerobic technology dates back more than 100 years, the technology is still under development, adapting novel treatment systems to the modern...

  17. Targeted modification of organic components of municipal solid waste by short-term pre-aeration and its enhancement on anaerobic degradation in simulated landfill bioreactors.

    Science.gov (United States)

    Ni, Zhe; Liu, Jianguo; Girotto, Francesca; Cossu, Raffaello; Qi, Guangxia

    2016-09-01

    Pre-aeration is effective on regulating subsequent anaerobic degradation of municipal solid waste (MSW) with high organic fractions during landfilling. The strength of pre-aeration should be optimized to intentionally remove some easily biodegradable fractions while conserve bio-methane potential as much as possible. This study investigates the evolution of organic components in MSW during 2-14days pre-aeration process and its impacts on subsequent anaerobic degradation in simulated landfill bioreactors. Results showed that a 6-day pre-aeration enabled to develop a thermophilic stage, which significantly accelerated biodegradation of organics except lignocelluloses, with removal rates of 42.8%, 76.7% and 25.1% for proteins, carbohydrates and lipids, respectively. Particularly, ammonia from accelerated ammonification in the thermophilic stage neutralized VFAs generated from anaerobic landfilling. As a result, the MSW with 6-day pre-aeration obtained the highest methane yield 123.4NL/kg dry matter. Therefore, it is recommended to interrupt pre-aeration before its cooling stage to switch to anaerobic landfilling. PMID:27243602

  18. Targeted modification of organic components of municipal solid waste by short-term pre-aeration and its enhancement on anaerobic degradation in simulated landfill bioreactors.

    Science.gov (United States)

    Ni, Zhe; Liu, Jianguo; Girotto, Francesca; Cossu, Raffaello; Qi, Guangxia

    2016-09-01

    Pre-aeration is effective on regulating subsequent anaerobic degradation of municipal solid waste (MSW) with high organic fractions during landfilling. The strength of pre-aeration should be optimized to intentionally remove some easily biodegradable fractions while conserve bio-methane potential as much as possible. This study investigates the evolution of organic components in MSW during 2-14days pre-aeration process and its impacts on subsequent anaerobic degradation in simulated landfill bioreactors. Results showed that a 6-day pre-aeration enabled to develop a thermophilic stage, which significantly accelerated biodegradation of organics except lignocelluloses, with removal rates of 42.8%, 76.7% and 25.1% for proteins, carbohydrates and lipids, respectively. Particularly, ammonia from accelerated ammonification in the thermophilic stage neutralized VFAs generated from anaerobic landfilling. As a result, the MSW with 6-day pre-aeration obtained the highest methane yield 123.4NL/kg dry matter. Therefore, it is recommended to interrupt pre-aeration before its cooling stage to switch to anaerobic landfilling.

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

    OpenAIRE

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

    2003-01-01

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

  20. Anaerobic wastewater treatment using anaerobic baffled bioreactor: a review

    Science.gov (United States)

    Hassan, Siti; Dahlan, Irvan

    2013-09-01

    Anaerobic wastewater treatment is receiving renewed interest because it offers a means to treat wastewater with lower energy investment. Because the microorganisms involved grow more slowly, such systems require clever design so that the microbes have sufficient time with the substrate to complete treatment without requiring enormous reactor volumes. The anaerobic baffled reactor has inherent advantages over single compartment reactors due to its circulation pattern that approaches a plug flow reactor. The physical configuration of the anaerobic baffled reactor enables significant modifications to be made; resulting in a reactor which is proficient of treating complex wastewaters which presently require only one unit, ultimately significant reducing capital costs. This paper also concerns about mechanism, kinetic and hydrodynamic studies of anaerobic digestion for future application of the anaerobic baffled reactor for wastewater treatment.

  1. Biochemistry of methyl-coenzyme M reductase: the nickel metalloenzyme that catalyzes the final step in synthesis and the first step in anaerobic oxidation of the greenhouse gas methane.

    Science.gov (United States)

    Ragsdale, Stephen W

    2014-01-01

    Methane, the major component of natural gas, has been in use in human civilization since ancient times as a source of fuel and light. Methanogens are responsible for synthesis of most of the methane found on Earth. The enzyme responsible for catalyzing the chemical step of methanogenesis is methyl-coenzyme M reductase (MCR), a nickel enzyme that contains a tetrapyrrole cofactor called coenzyme F430, which can traverse the Ni(I), (II), and (III) oxidation states. MCR and methanogens are also involved in anaerobic methane oxidation. This review describes structural, kinetic, and computational studies aimed at elucidating the mechanism of MCR. Such studies are expected to impact the many ramifications of methane in our society and environment, including energy production and greenhouse gas warming.

  2. Proteomic analysis of acetylation in thermophilic Geobacillus kaustophilus.

    Science.gov (United States)

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

    2013-08-01

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

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

    Science.gov (United States)

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

    2015-08-15

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

  4. 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.

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

    Science.gov (United States)

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

    1993-01-01

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

  6. Economic viability of anaerobic digestion

    Energy Technology Data Exchange (ETDEWEB)

    Wellinger, A. [INFOENERGIE, Ettenhausen (Switzerland)

    1996-01-01

    The industrial application of anaerobic digestion is a relatively new, yet proven waste treatment technology. Anaerobic digestion reduces and upgrades organic waste, and is a good way to control air pollution as it reduces methane and nitrous gas emissions. For environmental and energy considerations, anaerobic digestion is a nearly perfect waste treatment process. However, its economic viability is still in question. A number of parameters - type of waste (solid or liquid), digester system, facility size, product quality and end use, environmental requirements, cost of alternative treatments (including labor), and interest rates - define the investment and operating costs of an anaerobic digestion facility. Therefore, identical facilities that treat the same amount and type of waste may, depending on location, legislation, and end product characteristics, reveal radically different costs. A good approach for evaluating the economics of anaerobic digestion is to compare it to treatment techniques such as aeration or conventional sewage treatment (for industrial wastewater), or composting and incineration (for solid organic waste). For example, the cost (per ton of waste) of in-vessel composting with biofilters is somewhat higher than that of anaerobic digestion, but the investment costs 1 1/2 to 2 times more than either composting or anaerobic digestion. Two distinct advantages of anaerobic digestion are: (1) it requires less land than either composting or incinerating, which translates into lower costs and milder environmental and community impacts (especially in densely populated areas); and (2) it produces net energy, which can be used to operate the facility or sold to nearby industries.

  7. Anaerobic Digestion of Piggery Waste

    NARCIS (Netherlands)

    Velsen, van A.F.M.

    1981-01-01

    Anaerobic digestion is a biological process by which organic matter is converted to methane and carbon dioxide by microbes in the absence of air (oxygen). In nature, anaerobic conversions occur at all places where organic material accumulates and the supply of oxygen is deficient, e.g. in marshes an

  8. Thermophilic biological nitrogen removal in industrial wastewater treatment.

    OpenAIRE

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

    2013-01-01

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

  9. Sulfur Reduction by the Extremely Thermophilic Archaebacterium Pyrodictium occultum

    OpenAIRE

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

    1987-01-01

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

  10. On the kinetics of anaerobic power

    Directory of Open Access Journals (Sweden)

    Moxnes John F

    2012-07-01

    Full Text Available Abstract Background This study investigated two different mathematical models for the kinetics of anaerobic power. Model 1 assumes that the work power is linear with the work rate, while Model 2 assumes a linear relationship between the alactic anaerobic power and the rate of change of the aerobic power. In order to test these models, a cross country skier ran with poles on a treadmill at different exercise intensities. The aerobic power, based on the measured oxygen uptake, was used as input to the models, whereas the simulated blood lactate concentration was compared with experimental results. Thereafter, the metabolic rate from phosphocreatine break down was calculated theoretically. Finally, the models were used to compare phosphocreatine break down during continuous and interval exercises. Results Good similarity was found between experimental and simulated blood lactate concentration during steady state exercise intensities. The measured blood lactate concentrations were lower than simulated for intensities above the lactate threshold, but higher than simulated during recovery after high intensity exercise when the simulated lactate concentration was averaged over the whole lactate space. This fit was improved when the simulated lactate concentration was separated into two compartments; muscles + internal organs and blood. Model 2 gave a better behavior of alactic energy than Model 1 when compared against invasive measurements presented in the literature. During continuous exercise, Model 2 showed that the alactic energy storage decreased with time, whereas Model 1 showed a minimum value when steady state aerobic conditions were achieved. During interval exercise the two models showed similar patterns of alactic energy. Conclusions The current study provides useful insight on the kinetics of anaerobic power. Overall, our data indicate that blood lactate levels can be accurately modeled during steady state, and suggests a linear

  11. Inactivation of a bovine enterovirus and a bovine parvovirus in cattle manure by anaerobic digestion, heat treatment, gamma irradiation, ensilage and composting

    Energy Technology Data Exchange (ETDEWEB)

    Monteith, H.D.; Shannon, E.E.; Derbyshire, J.B.

    1986-08-01

    A bovine enterovirus and a bovine parvovirus seeded into liquid cattle manure were rapidly inactivated by anaerobic digestion under thermophilic conditions (55/sup 0/C), but the same viruses survived for up to 13 and 8 days respectively under mesophilic conditions (35/sup 0/C). The enterovirus was inactivated in digested liquid manure heated to 70/sup 0/C for 30 min, but the parvovirus was not inactivated by this treatment. The enterovirus, seeded into single cell protein (the solids recovered by centrifugation of digested liquid manure), was inactivated by a gamma irradiation dose of 1.0 Mrad, but the parvovirus survived this dose. When single cell protein seeded with bovine enterovirus or bovine parvovirus was ensiled with cracked corn, the enterovirus was inactivated after a period of 30 days, while the parvovirus survived for 30 days in one of two experiments. Neither the enterovirus nor the parvovirus survived composting for 28 days in a thermophilic aerobic environment when seeded into the solid fraction of cattle manure. It was concluded that, of the procedures tested, only anaerobic digestion under thermophilic conditions appeared to be reliable method of viral inactivation to ensure the safety of single cell protein for refeeding to livestock. Composting appeared to be a suitable method for the disinfection of manure for use as a soil conditioner.

  12. The inactivation of a bovine enterovirus and a bovine parvovirus in cattle manure by anaerobic digestion, heat treatment, gamma irradiation, ensilage and composting.

    Science.gov (United States)

    Monteith, H D; Shannon, E E; Derbyshire, J B

    1986-08-01

    A bovine enterovirus and a bovine parvovirus seeded into liquid cattle manure were rapidly inactivated by anaerobic digestion under thermophilic conditions (55 degrees C), but the same viruses survived for up to 13 and 8 days respectively under mesophilic conditions (35 degrees C). The enterovirus was inactivated in digested liquid manure heated to 70 degrees C for 30 min, but the parvovirus was not inactivated by this treatment. The enterovirus, seeded into single cell protein (the solids recovered by centrifugation of digested liquid manure), was inactivated by a gamma irradiation dose of 1.0 Mrad, but the parvovirus survived this dose. When single cell protein seeded with bovine enterovirus or bovine parvovirus was ensiled with cracked corn, the enterovirus was inactivated after a period of 30 days, while the parvovirus survived for 30 days in one of two experiments. Neither the enterovirus nor the parvovirus survived composting for 28 days in a thermophilic aerobic environment when seeded into the solid fraction of cattle manure. It was concluded that, of the procedures tested, only anaerobic digestion under thermophilic conditions appeared to be reliable method of viral inactivation to ensure the safety of single cell protein for refeeding to livestock. Composting appeared to be a suitable method for the disinfection of manure for use as a soil conditioner.

  13. Monitoring and control of anaerobic reactors

    DEFF Research Database (Denmark)

    Pind, Peter Frode; Angelidaki, Irini; Ahring, Birgitte Kiær;

    2003-01-01

    measurements are reviewed in detail. In the sequel, possible manipulated variables, such as the hydraulic retention time, the organic loading rate, the sludge retention time, temperature, pH and alkalinity are evaluated with respect to the two main reactor types: high-rate and low-rate. Finally, the different......The current status in monitoring and control of anaerobic reactors is reviewed. The influence of reactor design and waste composition on the possible monitoring and control schemes is examined. After defining the overall control structure, and possible control objectives, the possible process...

  14. Anaerobic Digestion. Instructor's Guide. Biological Treatment Process Control.

    Science.gov (United States)

    Carnegie, John W., Ed.

    This instructor's guide contains materials needed to teach a four-lesson unit on anaerobic digestion control. These materials include: (1) unit overview; (2) lesson plans; (3) lecture outlines; (4) student worksheets for each lesson (with answers); and (5) two copies of a final quiz (with and without answers). Lesson 1 is a review of the theory of…

  15. Hydrogenosomes : convergent adaptations of mitochondria to anaerobic environments

    NARCIS (Netherlands)

    Hackstein, JHP; Akhmanova, A; Voncken, F; van Hoek, A; van Alen, T; Boxma, B; Moon-van der Staay, SY; van der Staay, G; Leunissen, J; Huynen, M; Rosenberg, J; Veenhuis, M; Hackstein, Johannes H.P.; Moon-van der Staay, Seung Yeo

    2001-01-01

    Hydrogenosomes are membrane-bound organelles that compartmentalise the Final steps of energy metabo I is in in a number of anaerobic eukaryotes. They produce hydrogen and ATP. Here we will review the data, which are relevant for the questions: how did the hydrogenosomes originate, and what was their

  16. Comparison of two-stage thermophilic (68 degrees C/55 degrees C) anaerobic digestion with one-stage thermophilic (55 degrees C) digestion of cattle manure

    DEFF Research Database (Denmark)

    Nielsen, H.B.; Mladenovska, Zuzana; Westermann, Peter;

    2004-01-01

    -stage reactor. The 68degreesC reactor generated 7% to 9% of the total amount of methane of the two-stage system and maintained a volatile fatty acids (VFA) concentration of 4.0 to 4.4 g acetate per liter. Population size and activity of aceticlastic methanogens, syntrophic bacteria, and hydrolytic....../fermentative bacteria were significantly lower in the 68degreesC reactor than in the 55degreesC reactors. The density levels of methanogens utilizing H-2/CO2 or formate were, however, in the same range for all reactors, although the degradation of these substrates was significantly lower in the 68degreesC reactor than...

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

    DEFF Research Database (Denmark)

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

    2004-01-01

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

  18. Anaerobic fungal populations

    International Nuclear Information System (INIS)

    The development of molecular techniques has greatly broadened our view of microbial diversity and enabled a more complete detection and description of microbial communities. The application of these techniques provides a simple means of following community changes, for example, Ishii et al. described transient and more stable inhabitants in another dynamic microbial system, compost. Our present knowledge of anaerobic gut fungal population diversity within the gastrointestinal tract is based upon isolation, cultivation and observations in vivo. It is likely that there are many species yet to be described, some of which may be non-culturable. We have observed a distinct difference in the ease of cultivation between the different genera, for example, Caecomyes isolates are especially difficult to isolate and maintain in vitro, a feature that is likely to result in the under representation of this genera in culture-based enumerations. The anaerobic gut fungi are the only known obligately anaerobic fungi. For the majority of their life cycles, they are found tightly associated with solid digesta in the rumen and/or hindgut. They produce potent fibrolytic enzymes and grow invasively on and into the plant material they are digesting making them important contributors to fibre digestion. This close association with intestinal digesta has made it difficult to accurately determine the amount of fungal biomass present in the rumen, with Orpin suggesting 8% contribution to the total microbial biomass, whereas Rezaeian et al. more recently gave a value of approximately 20%. It is clear that the rumen microbial complement is affected by dietary changes, and that the fungi are more important in digestion in the rumens of animals fed with high-fibre diets. It seems likely that the gut fungi play an important role within the rumen as primary colonizers of plant fibre, and so we are particularly interested in being able to measure the appearance and diversity of fungi on the plant

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

    Science.gov (United States)

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

    2010-09-01

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

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

    Directory of Open Access Journals (Sweden)

    Tony J. Pembroke

    2010-09-01

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

  1. Optimisation of 16S rDNA amplicon sequencing protocols for microbial community profiling of anaerobic digesters

    DEFF Research Database (Denmark)

    Kirkegaard, Rasmus Hansen; McIlroy, Simon Jon; Larsen, Poul;

    of the community composition. As such sample specific optimisation and standardisation of DNA extraction, as well PCR primer selection, are essential to minimising the potential for such biases. The aim of this study was to develop a protocol for optimized community profiling of anaerobic digesters. The FastDNA......RNA gene amplicon sequencing is rapid, cheap, high throughput, and has high taxonomic resolution. However, biases are introduced in multiple steps of this approach, including non-representative DNA extraction and uneven taxonomic coverage of selected PCR primers, potentially giving a skewed view...... SPIN kit was selected and the mechanical lysis parameters optimised for extraction of genomic DNA from mesophilic and thermophilic anaerobic digester samples. Different primer sets were compared for targeting the archaea and bacteria, both together and individually. Shotgun sequencing of a TruSeq PCR...

  2. Obtaining representative community profiles of anaerobic digesters through optimisation of 16S rRNA amplicon sequencing protocols

    DEFF Research Database (Denmark)

    Kirkegaard, Rasmus Hansen; McIlroy, Simon Jon; Karst, Søren Michael;

    of the community composition . As such sample specific optimisation and standardisation of DNA extraction, as well PCR primer selection, are essential to minimising the potential for such biases. The aim of this study was to develop a protocol for optimized community profiling of anaerobic digesters. The FastDNA......RNA gene amplicon sequencing is rapid, cheap, high throughput, and has high taxonomic resolution. However, biases are introduced in multiple steps of this approach, including non-representative DNA extraction and uneven taxonomic coverage of selected PCR primers, potentially giving a skewed view...... SPIN kit was selected and the mechanical lysis parameters optimised for extraction of genomic DNA from mesophilic and thermophilic anaerobic digester samples. Different primer sets were compared for targeting the archaea and bacteria, both together and individually . Shotgun sequencing...

  3. Fermentative hydrogen production from cassava stillage by mixed anaerobic microflora: Effects of temperature and pH

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Gang; Xie, Li; Zou, Zhonghai; Zhou, Qi [Key Laboratory of Yangtze River Water Environment, Ministry of Education (Tongji University), UNEP-Tongji, Tongji University, Siping Road No. 1239, Shanghai 200092 (China); Wang, Jing-Yuan (School of Civil and Environmental Engineering, Nanyang Technological University, N1-01b-45, 50 Nanyang Avenue, 639798 Singapore)

    2010-12-15

    Fermentative hydrogen production from cassava stillage was conducted to investigate the influences of temperature (37 C, 60 C, 70 C) and initial pH (4-10) in batch experiments. Although the seed sludge was mesophilic anaerobic sludge, maximum hydrogen yield (53.8 ml H{sub 2}/gVS) was obtained under thermophilic condition (60 C), 53.5% and 198% higher than the values under mesophilic (37 C) and extreme-thermophilic (70 C) conditions respectively. The difference was mainly due to the different VFA and ethanol distributions. Higher hydrogen production corresponded with higher ratios of butyrate/acetate and butyrate/propionate. Similar hydrogen yields of 66.3 and 67.8 ml H{sub 2}/gVS were obtained at initial pH 5 and 6 respectively under thermophilic condition. The total amount of VFA and ethanol increased from 3536 to 7899 mg/l with the increase of initial pH from 4 to 10. Initial pH 6 was considered as the optimal pH due to its 19% higher total VFA and ethanol concentration than that of pH 5. Homoacetogenesis and methonogenesis were very dependent on the initial pH and temperature even when the inoculum was heat-pretreated. Moreover, a difference between measured and theoretical hydrogen was observed in this study, which could be attributed to homoacetogenesis, methanogenesis and the degradation of protein. (author)

  4. Thermophilic co-digestion of organic fraction of municipal solid wastes with FOG wastes from a sewage treatment plant: reactor performance and microbial community monitoring.

    Science.gov (United States)

    Martín-González, Lucia; Castro, Rita; Pereira, M Alcina; Alves, M Madalena; Font, Xavier; Vicent, Teresa

    2011-04-01

    Working at thermophilic conditions instead of mesophilic, and also the addition of a co-substrate, are both the ways to intend to improve the anaerobic digestion of the source-collected organic fraction of municipal solid wastes (SC-OFMSW). Addition of sewage treatment plant fat, oil and grease wastes (STP-FOGW), that are nowadays sent to landfill, would represent an opportunity to recover a wasted methane potential and, moreover, improve the whole process. In this study, after a first period feeding only SC-OFMSW, a co-digestion step was performed maintaining thermophilic conditions. During the co-digestion period enhancements in biogas production (52%) and methane yield (36%) were achieved. In addition, monitoring of microbial structure by using PCR-DGGE and cloning techniques showed that bacterial community profiles clustered in two distinct groups, before and after the extended contact with STP-FOGW, being more affected by the STP-FOGW addition than the archaeal one. PMID:21320771

  5. Clostridium tepidiprofundi sp. nov., a moderately thermophilic bacterium from a deep-sea hydrothermal vent.

    Science.gov (United States)

    Slobodkina, G B; Kolganova, T V; Tourova, T P; Kostrikina, N A; Jeanthon, C; Bonch-Osmolovskaya, E A; Slobodkin, A I

    2008-04-01

    A moderately thermophilic, anaerobic bacterium (strain SG 508T) was isolated from a hydrothermal vent chimney located at 1 degrees N on the East Pacific Rise at a depth of 2650 m. Cells of strain SG 508T were straight to slightly curved rods, 0.4-0.6 microm in diameter and 2.0-3.0 microm in length. Spore formation was observed only below pH 5.5. The temperature range for growth was 22-60 degrees C, with optimum growth at 50 degrees C. The pH range for growth was 4.0-8.5, with optimum growth at pH 6.0-6.8. Growth of strain SG 508T was observed at NaCl concentrations ranging from 1.0 to 6.0 % (w/v), with optimum growth at 2.5 % (w/v). Substrates utilized by strain SG 508T included casein, peptone, tryptone, yeast extract, beef extract, starch, maltose and glucose. The products of glucose fermentation were ethanol, acetate, H2, formate and CO2. Strain SG 508T was able to reduce elemental sulfur to hydrogen sulfide. The DNA G+C content of strain SG 508T was 30.9 mol%. 16S rRNA gene sequence analysis revealed that the isolated organism belonged to cluster I of the genus Clostridium. On the basis of its physiological properties and data from phylogenetic analyses, strain SG 508T is considered to represent a novel species of the genus Clostridium, for which the name Clostridium tepidiprofundi sp. nov. is proposed. The type strain is SG 508T (=DSM 19306T =VKM B-2459T).

  6. Hybrid alkali-hydrodynamic disintegration of waste-activated sludge before two-stage anaerobic digestion process.

    Science.gov (United States)

    Grübel, Klaudiusz; Suschka, Jan

    2015-05-01

    The first step of anaerobic digestion, the hydrolysis, is regarded as the rate-limiting step in the degradation of complex organic compounds, such as waste-activated sludge (WAS). The aim of lab-scale experiments was to pre-hydrolyze the sludge by means of low intensive alkaline sludge conditioning before applying hydrodynamic disintegration, as the pre-treatment procedure. Application of both processes as a hybrid disintegration sludge technology resulted in a higher organic matter release (soluble chemical oxygen demand (SCOD)) to the liquid sludge phase compared with the effects of processes conducted separately. The total SCOD after alkalization at 9 pH (pH in the range of 8.96-9.10, SCOD = 600 mg O2/L) and after hydrodynamic (SCOD = 1450 mg O2/L) disintegration equaled to 2050 mg/L. However, due to the synergistic effect, the obtained SCOD value amounted to 2800 mg/L, which constitutes an additional chemical oxygen demand (COD) dissolution of about 35 %. Similarly, the synergistic effect after alkalization at 10 pH was also obtained. The applied hybrid pre-hydrolysis technology resulted in a disintegration degree of 28-35%. The experiments aimed at selection of the most appropriate procedures in terms of optimal sludge digestion results, including high organic matter degradation (removal) and high biogas production. The analyzed soft hybrid technology influenced the effectiveness of mesophilic/thermophilic anaerobic digestion in a positive way and ensured the sludge minimization. The adopted pre-treatment technology (alkalization + hydrodynamic cavitation) resulted in 22-27% higher biogas production and 13-28% higher biogas yield. After two stages of anaerobic digestion (mesophilic conditions (MAD) + thermophilic anaerobic digestion (TAD)), the highest total solids (TS) reduction amounted to 45.6% and was received for the following sample at 7 days MAD + 17 days TAD. About 7% higher TS reduction was noticed compared with the sample after 9

  7. 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.

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

    DEFF Research Database (Denmark)

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

    2004-01-01

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

  9. Anaerobic Biodegradation of Reactive Red KE-3B%活性红KE-3B的厌氧降解

    Institute of Scientific and Technical Information of China (English)

    王天广; 王新海; 马同森; 马骏; 李德亮

    2012-01-01

    考察了活性红KE-3B在中温(35℃)、高温(55℃)条件下的厌氧降解性,从产气量、脱色率、VFAs、CODcr去除率等方面研究了其处理效果和降解机理.结果表明,活性红KE-3B不易被完全矿化,只是发生了初级降解;中温条件下有利于提高生物气中的甲烷比率,但VFAs积累较多,对最终生化降解起到了抑制作用;高温条件下,脱色率随染料的浓度增大而减小,并且在同等条件下比中温时脱色率高,最高达到97.40%,同时高温时的CODCr去除率也相对较高,达到了84.53%.活性红KE-3B废水更适合低浓度高温处理,理想处理浓度≤80 mg/L(以C计).%The anaerobic biodegradability of reactive red KE-3B was studied in batch experiments under mesophilic (35 'C)and thermophilic(55 ℃)conditions, and the factors such as decolorization rate, VFAs,CODr.r removal rate etc, were detected to evaluate its treatment effects and degradation mechanism. The results showed that the reactive red KE-3B was difficult to be anaerobic biodegraded into CO2 and CH4 ultimately, and further to say the decolorization was just due to primary degradation. The ratio of CH4 in biogas was higher under mesophilic condition, but the value of VFAs was high, which had inhibited the ultimate biodegradation. The decolorization rate decreased as the dye concentration increased under thermophilic condition. Compared with the mesophilic tests, the higher decolorization rate was obtained in the thermophilic tests under the same conditions, with the highest decolorization rate of 97. 40 %. The highest CODcr removal rate, which was also higher under thermophilic condition, could attain 84. 53 %. Based on these results, the conclusion to be made was that the treatment of reactive red KE-3B wastewater, was more suitable for low concentration under thermophilic condition, which ideal treatment concentration was ≤80 mg/L(calculated by C).

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

    Science.gov (United States)

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

    2011-10-02

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-10-02

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

  12. 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.

  13. The isolation and characterization of new C. thermocellum strains and the evaluation of multiple anaerobic digestion systems

    Science.gov (United States)

    Lv, Wen

    The overall objective of my research was to improve the efficiencies of bioconversions that produce renewable energy from lignocellulosic biomass. To this end, my studies addressed issues important to two promising strategies: consolidated bioprocessing (CBP) and anaerobic digestion (AD). CBP achieves saccharolytic enzyme production, hydrolysis, and fermentation in a single step and is considered to be the most cost-effective model. Anaerobic bacteria that can be used in CBP are highly desirable. To that end, two thermophilic and cellulolytic bacterial strains were isolated and characterized (Chapter 3). Based on 16S rRNA gene sequence analysis, both strains CS7 and CS8 are closely related to Clostridium thermocellum ATCC 27405. However, they had significantly higher specific cellulase activities and ethanol/acetate ratios than C. thermocellum ATCC 27405. As a result, CS7 and CS8 are two new highly cellulolytic and ethanologenic C. thermocellum strains, with application potentials in research and development of CBP. As some of the most promising AD processes, two temperature-phased AD (TPAD) systems, in comparison with a thermophilic single-stage AD (TSAD) system and a mesophilic two-stage AD (MTAD) system, were studied in treating high-strength dairy cattle manure. The TPAD systems, with the thermophilic digesters acidified (AT-TPAD, Chapter 4) or operated at neutral pH (NT-TPAD, Chapter 5), were optimized at the thermophilic temperature of 50°C and a volume ratio between the thermophilic and the mesophilic digesters of 1:2. Despite similar methane productions, the NT-TPAD system achieved significantly higher volatile solid (VS) removal than the AT-TPAD system and needed no external pH adjustments (Chapter 6). At the same overall OLR, the TSAD system achieved the highest performance, followed by the NT-TPAD and the MTAD systems (Chapter 7). Each digester harbored distinct yet dynamic microbial populations, some of which were significantly correlated or associated

  14. Defining Anaerobic Digestion Stability-Full Scale Study

    Science.gov (United States)

    Demitry, M. E., Sr.

    2014-12-01

    A full-scale anaerobic digester receiving a mixture of primary and secondary sludge was monitored for one hundred days. A chemical oxygen demand, COD, and a volatile solids, VS, mass balance was conducted to evaluate the stability of the digester and its capability of producing methane gas. The COD mass balance could account for nearly 90% of the methane gas produced while the VS mass balance showed that 91% of the organic matter removed resulted in biogas formation. Other parameters monitored included: pH, alkalinity, VFA, and propionic acid. The values of these parameters showed that steady state had occurred. Finally, at mesophilic temperature and at steady state performance, the anaerobic digester stability was defined as a constant ratio of methane produced per substrate of ΔVS (average ratio=0.404 l/g). This ratio can be used as universal metric to determine the anaerobic digester stability in an easy and inexpensive way.

  15. Enhanced Versus Conventional Sludge Anaerobic Processes: Performances and Techno-Economic Assessment.

    Science.gov (United States)

    Gianico, Andrea; Bertanza, Giorgio; Braguglia, Camilla M; Canato, Matteo; Gallipoli, Agata; Laera, Giuseppe; Levantesi, Caterina; Mininni, Giuseppe

    2016-05-01

    Sewage sludge processing is a key issue in water resource recovery facilities due to the inefficacy of conventional treatments to produce high quality biosolids to be safely used in agriculture. Under this framework, the performances of several enhanced stabilization processes, namely ultrasound-pretreated Mesophilic Anaerobic Digestion (US+MAD), thermophilic anaerobic digestion (TAD), thermal-pretreated TAD (TH+TAD) and ultrasound-pretreated inverse Temperature Phased Anaerobic Digestion (US+iTPAD) have been investigated. Such enhanced processes resulted in higher biogas yields and higher destruction of pathogens with respect to conventional MAD process, thus suggesting their feasibility in full-scale implementation perspectives. A procedure for technical-economic comparison of new sludge processing lines against conventional ones (benchmarking) was developed, based on the definition of technical issues (e.g. reliability, complexity, etc.) which are rated for each situation. Moreover, capital and operating costs were estimated. The enhanced processes analyzed in this work showed some potentially critical items, mainly related to energy balance and reagent consumption. PMID:27131310

  16. Biological methods for increasing the biogas yield of livestock waste. Final report; Biologiske metoder til foroegelse af husdyrgoednings biogaspotentiale. Slutrapport

    Energy Technology Data Exchange (ETDEWEB)

    Mladenovska, Z.; Ahring, B.K.

    2001-01-01

    Danish full-scale biogas plants operate with manure as a primary substrate, of which cattle manure represents a significant fraction. Conversion of the lignocellulosic fibre fraction of manure was shown to be the rate-degrading step of the anaerobic digestion. The aim of this project was to investigate if the biological methods, such as bioaugmentation of the reactor with specific anaerobic, hydrolytic bacteria would improve hydrolysis of fibres and result in an increase of the methane yield of cattle manure. Results of this study showed, that there is a potential for an increase of the methane yield of manure by inoculating the fibre-containing substrate with cellulose- and alkaliphilic xylane-hydrolyzing bacterial cultures. The highest increase of methane yield in batch experiment was obtained at 37 deg. C and 68 deg. C, while the effect at 55 deg. C was poor. Direct inoculation of a mesophilic reactor with Clostridium cellulovorans (DSM 3052) was not successful. The fate of the organism, followed by 16S rRNA probing, proved that DSM 3052 was not a member of the indigenous microflora, and that the active population of DSM 3052 could not be established within the reactor. On the other hand, inoculation of a reactor with our own isolate, a new clostridial strain, Clostridium sp. SA 14, resulted in a significant increase of the methane yield from 220 ml CH{sub 4}/g VS up to 330 ml CH{sub 4}/g VS. However, during the continuous reactor operation in the period of one retention time, the effect was reduced and finally disappeared. Therefore, it would be necessary in the future to develop a new strategy for establishment of this strain within the reactor environment. Anaerobic digestion of manure was also studied in a two-step process, where manure was first hydrolyzed at 68 deg. C, and thereafter digested in a conventional methanogenic step at 55 deg. C. Investigation from batch experiment resulted in a 24%- increase in methane yield for the two-step digestion compared

  17. Investigation into the effect of high concentrations of volatile fatty acids in anaerobic digestion on methanogenic communities

    Energy Technology Data Exchange (ETDEWEB)

    Franke-Whittle, Ingrid H., E-mail: ingrid.whittle@uibk.ac.at [Institut für Mikrobiologie, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck (Austria); Walter, Andreas [Institut für Mikrobiologie, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck (Austria); Ebner, Christian [Abwasserverband Zirl und Umgebung, Meilbrunnen 5, 6170 Zirl (Austria); Insam, Heribert [Institut für Mikrobiologie, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck (Austria)

    2014-11-15

    Highlights: • Different methanogenic communities in mesophilic and thermophilic reactors. • High VFA levels do not cause major changes in archaeal communities. • Real-time PCR indicated greater diversity than ANAEROCHIP microarray. - Abstract: A study was conducted to determine whether differences in the levels of volatile fatty acids (VFAs) in anaerobic digester plants could result in variations in the indigenous methanogenic communities. Two digesters (one operated under mesophilic conditions, the other under thermophilic conditions) were monitored, and sampled at points where VFA levels were high, as well as when VFA levels were low. Physical and chemical parameters were measured, and the methanogenic diversity was screened using the phylogenetic microarray ANAEROCHIP. In addition, real-time PCR was used to quantify the presence of the different methanogenic genera in the sludge samples. Array results indicated that the archaeal communities in the different reactors were stable, and that changes in the VFA levels of the anaerobic digesters did not greatly alter the dominating methanogenic organisms. In contrast, the two digesters were found to harbour different dominating methanogenic communities, which appeared to remain stable over time. Real-time PCR results were inline with those of microarray analysis indicating only minimal changes in methanogen numbers during periods of high VFAs, however, revealed a greater diversity in methanogens than found with the array.

  18. The influence of the temperature regime on the formation of methane in a two-phase anaerobic digestion process

    Energy Technology Data Exchange (ETDEWEB)

    Schoenberg, Mandy; Linke, Bernd

    2012-06-15

    The influence of different temperature levels on the formation of methane in a two-phase anaerobic digestion process using rye silage and barley straw as feedstocks was investigated in this study. This process comprised a leach-bed reactor (LBR), a reservoir for leachate from the LBR, and a separate downstream fixed-film anaerobic filter (AF), with immobilized micro biocoenosises. The degree of degradation of the volatile solids was similar in both studies and was almost equal at 75 Ma.-%{sub VS}. When both reactor phases were operated at thermophilic conditions, the main substrate turnover was observed in the LBR(58% of the total methane yield, with an average methane content of 41 Vol.-%). Only the excess of organic fraction in the process-liquid was transformed in the AF(42% of the total methane yield, with an average methane content of 74 Vol.-%). When the parts of the reactor system operated at different temperature regimes, thermophilic hydrolysis/acidogenesis phase and mesophilic methanization, a separation of carbon dioxide and methane production, was observed. A total methane yield of 88%, with an average methane content of 85 Vol.-%, was formed in the AF. The generated biogas with high methane concentrations is suitable for feeding the purified biomethane into the natural gas grid. Furthermore, it can be used as fuel for cars and tractors. (copyright 2012 WILEY-VCH Verlag GmbH 8 Co. KGaA, Weinheim)

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

    Directory of Open Access Journals (Sweden)

    Rajesh K. Sani

    2011-11-01

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

  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. Microbial community in anaerobic hydrogen-producing microflora enriched from sludge compost.

    Science.gov (United States)

    Ueno, Y; Haruta, S; Ishii, M; Igarashi, Y

    2001-11-01

    Hydrogen production by thermophilic anaerobic microflora enriched from sludge compost was studied by using an artificial medium containing cellulose powder. Hydrogen gas was evolved with the formation of acetate, ethanol, and butyrate by decomposition of the cellulose powder. The hydrogen production yield was 2.0 mol/mol-hexose by either batch or chemostat cultivation. A medium that did not contain peptone demonstrated a lower hydrogen production yield of 1.0 mol/mol-hexose with less formation of butyrate. The microbial community in the microflora was investigated through isolation of the microorganisms by both plating and denaturing gradient gel electrophoresis (DGGE) of the' PCR-amplified V3 region of 16S rDNA. Sixty-eight microorganisms were isolated from the microflora and classified into nine distinct groups by genetic fingerprinting of the PCR-DGGE or by a random amplified polymorphic DNA analysis and determination of the partial sequence of 16S rDNA. Most of the isolates belonged to the cluster of the thermophilic Clostridium/Bacillus subphylum of low G+C gram-positive bacteria. Product formation by most of the isolated strains corresponded to that produced by the microflora. Thermoanaerobacterium thermosaccharolyticium was isolated in the enrichment culture with or without added peptone. and was detected with strong intensity by PCR-DGGE. Two other thermophilic cellulolytic microorganisms, Clostridium thermocellum and Clostridium cellulosi, were also detected by PCR-DGGE, although they could not be isolated. These findings imply that hydrogen production from cellulose by microflora is performed by a consortium of several species of microorganisms.

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

    Directory of Open Access Journals (Sweden)

    Kathleen D Cusick

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

  3. Comparing the value of bioproducts from different stages of anaerobic membrane bioreactors.

    Science.gov (United States)

    Khan, M A; Ngo, H H; Guo, W S; Liu, Y W; Zhou, J L; Zhang, J; Liang, S; Ni, B J; Zhang, X B; Wang, J

    2016-08-01

    The anaerobic digestion process in anaerobic membrane bioreactors is an effective way for waste management, energy sustainability and pollution control in the environment. This digestion process basically involves the production of volatile fatty acids and biohydrogen as intermediate products and methane as a final product. This paper compares the value of bioproducts from different stages of anaerobic membrane bioreactors through a thorough assessment. The value was assessed in terms of technical feasibility, economic assessment, environmental impact and impact on society. Even though the current research objective is more inclined to optimize the production of methane, the intermediate products could also be considered as economically attractive and environment friendly options. Hence, this is the first review study to correlate the idea into an anaerobic membrane bioreactor which is expected to guide future research pathways regarding anaerobic process and its bioproducts. PMID:27233838

  4. Hydrogen and thiosulfate limits for growth of a thermophilic, autotrophic Desulfurobacterium species from a deep-sea hydrothermal vent.

    Science.gov (United States)

    Stewart, Lucy C; Llewellyn, James G; Butterfield, David A; Lilley, Marvin D; Holden, James F

    2016-04-01

    Hydrothermal fluids (341°C and 19°C) were collected < 1 m apart from a black smoker chimney and a tubeworm mound on the Boardwalk edifice at the Endeavour Segment in the northeastern Pacific Ocean to study anaerobic microbial growth in hydrothermal mineral deposits. Geochemical modelling of mixed vent fluid and seawater suggests the mixture was anoxic above 55°C and that low H2 concentrations (79 μmol kg(-1) in end-member hydrothermal fluid) limit anaerobic hydrogenotrophic growth above this temperature. A thermophilic, hydrogenotrophic sulfur reducer, Desulfurobacterium strain HR11, was isolated from the 19°C fluid raising questions about its H2 -dependent growth kinetics. Strain HR11 grew at 40-77°C (Topt 72-75°C), pH 5-8.5 (pHopt 6-7) and 1-5% (wt vol(-1) ) NaCl (NaClopt 3-4%). The highest growth rates occurred when S2 O3 (2-) and S° were reduced to H2 S. Modest growth occurred by NO3 (-) reduction. Monod constants for its growth were Ks of 30 μM for H2 and Ks of 20 μM for S2 O3 (2-) with a μmax of 2.0 h(-1) . The minimum H2 and S2 O3 (2-) concentrations for growth were 3 μM and 5 μM respectively. Possible sources of S2 O3 (2-) and S° are from abiotic dissolved sulfide and pyrite oxidation by O2 .

  5. Life Cycle Assessment of different uses of biogas from anaerobic digestion of separately collected biodegradable waste in France. Final report; Analyse du Cycle de Vie des modes de valorisation energetique du biogaz issu de methanisation de la Fraction Fermentescible des Ordures Menageres collectee selectivement en France. Rapport Final

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-01

    In the first part of the study, Gaz de France (GdF) and the French Environment Energy Management Agency (ADEME) wished to identify the best method to use the biogas from anaerobic digestion of separately collected biodegradable waste (bio-waste). Secondly, GdF and ADEME wished to evaluate the strength and weaknesses of the two main different organic recycling: anaerobic digestion (methanization) and composting. The study is based on the life cycle assessment method. The life cycle assessment used for this study consists in quantifying the environmental impacts of all of the activities which are related to the chosen use method. This methodology involves compiling a detailed account of all substances and energy flows removed or emitted from or into the environment at each stage of the life cycle. These flows are then translated into indicators of potential environment impacts. This methodology is based on the international standards ISO14040 and ISO 14044. The life cycle assessment was performed by RDC Environnement. In this study, two questions were treated: - Which is the best valorisation method for biogas produced from the anaerobic digestion of separately collected biodegradable waste: fuel, heat or electricity? ('Biogas' question); - Which is the best treatment for the separately collected biodegradable waste: anaerobic digestion (methanization) or industrial composting? ('Composting' question). The field of the study includes the arrival of the separately collected biodegradable waste at the anaerobic unit as well as the utilisation of the biogas energy and the agricultural use of the digestate from anaerobic digestion. For each biogas utilisation, the environmental impacts of each life cycle stage were considered as well as the impacts that were avoided due to the substitution of the use of non-renewable energy ('conventional' procedures). The modelling of the direct composting of the biodegradable waste was realised taking into

  6. Thermophilic fermentative bacteria from a deep borehole in granitic rock in Sweden

    Science.gov (United States)

    Szewzyk, Ulrich; Szewzyk, Regine; Stenstroem, Thor-Axel

    1997-07-01

    A borehole drilled to a final depth of 6779 m in granitic rock in Gravberg, Sweden, was sampled and examined for the presence and activity of anaerobic bacteria. The application of anaerobic enrichment and isolation techniques resulted in pure cultures of various fermenting bacteria. Growth in enrichment cultures was observed only in those cultures inoculated from water samples from a depth of 3500 m. Pure cultures of anaerobic, fermenting bacteria were obtained with the following substrates: glucose, starch, xylane, ethanol, and lactate. All isolated bacteria were so far undiscribed bacteria by means of their physiological properties. One strain of the glucose fermenting bacteria was further characterized concerning its phylogenetic position and was found to be closest related to Clostridium thermohydrosulfuricum. However, by means of its characteristic metabolism, it was clearly separated from C. thermohydrosulfuricum. No sulfate-reducing or methanogenic bacteria were found in any of the samples. Fermentative bacteria growing in the presence of hematite often reduced the iron and induced the formation and deposition of insoluble iron sulfides.

  7. Comparison of solid-state anaerobic digestion and composting of yard trimmings with effluent from liquid anaerobic digestion.

    Science.gov (United States)

    Lin, Long; Yang, Liangcheng; Xu, Fuqing; Michel, Frederick C; Li, Yebo

    2014-10-01

    Solid-state anaerobic digestion (SS-AD) and composting of yard trimmings with effluent from liquid AD were compared under thermophilic condition. Total solids (TS) contents of 22%, 25%, and 30% were studied for SS-AD, and 35%, 45%, and 55% for composting. Feedstock/effluent (F/E) ratios of 2, 3, 4, 5, and 6 were tested. In composting, the greatest carbon loss was obtained at 35% TS, which was 2-3 times of that at 55% TS and was up to 50% higher than that in SS-AD. In SS-AD, over half of the degraded carbon was converted to methane with the greatest methane yield of 121 L/kg VS(feedstock). Methane production from SS-AD was low at F/E ratios of 2 and 3, likely due to the inhibitory effect of high concentrations of ammonia nitrogen (up to 5.6g/kg). The N-P-K values were similar for SS-AD digestate and compost with different dominant nitrogen forms.

  8. Anaerobic wastewater treatment and membrane filtration: a one night stand or a sustainable relationship?

    Science.gov (United States)

    Jeison, D; van Lier, J B

    2008-01-01

    Several anaerobic membrane bioreactors (AnMBR) were operated, under various conditions, applying different reactor configurations. Applicable fluxes were strongly determined by the physical properties of the sludge present in the reactors. Results show that particle size is a key determining factor for the attainable fluxes. Under thermophilic conditions, small sludge particle size was observed, resulting in low critical fluxes reaching 6-7 L/m2h for the submerged configuration and acidified substrate. In contrast, under mesophilic conditions critical fluxes of 20 L/m2h were obtained. The acidification level also showed a strong effect. Under thermophilic conditions, the presence of a significant fraction of non-acidified organic matter induced the growth of suspended acidogenic biomass that seriously affected the applicable fluxes, both in submerged and side-stream configurations. Under all conditions tested cake formation showed to be the limiting factor determining the applicable fluxes. Only low levels of irreversible fouling were observed. Due to technical and economical considerations, most interesting perspectives for the application of AnMBR are expected with the treatment of high-strength particulate wastewaters, and with extreme wastewaters characterised by high temperature, salinity, etc. PMID:18359991

  9. Biokinetic and molecular studies of methanogens in phased anaerobic digestion systems.

    Science.gov (United States)

    Zamanzadeh, Mirzaman; Parker, Wayne J; Verastegui, Yris; Neufeld, Josh D

    2013-12-01

    The influence of differing operational conditions of two-stage digesters on biokinetic characteristics and communities of methanogenic archaea was evaluated. Operating temperature of each phase influenced the archaeal communities significantly. Also, a strong correlation was observed between community composition and temperature and pH. The maximum specific substrate utilization rates (k max) of acetoclastic methanogens in the mesophilic and thermophilic 1st phases were 11.4 and 22.0 mgCOD mgCOD(-1)d(-1), respectively, whereas significantly lower k max values were estimated for the mesophilic and thermophilic 2nd-phase digesters which were 7.6 and 16.6 mgCOD mgCOD(-1)d(-1), respectively. It appeared that the biokinetic characteristics of the acetoclastic methanogen communities were reliant on digester loading rates. Also, higher temperature dependency coefficients (θ) were observed for the long retention time digesters when compared to the values computed for the 1st-phase digesters. Accordingly, the implementation of two sets of biokinetic parameters for acetoclastic methanogen will improve modeling of phased anaerobic digesters. PMID:24125797

  10. Industrial applications of the IWA anaerobic digestion model No. 1 (ADM1).

    Science.gov (United States)

    Batstone, D J; Keller, J

    2003-01-01

    In this paper, the IWA anaerobic digestion model No. 1 (ADM1) is applied to two case studies from contract work on industrial treatment plants. The first was the assessment of acid addition for pH decrease and avoidance of calcium carbonate (CaCO3) precipitation in a paper mill fed UASB. The simulation work found, with a high degree of confidence, that acid dosing was neither economical for pH control, nor had any real effect on the CaCO3 levels present in the reactor. A specific calcium carbonate precipitation equation was added to the ADM1 to undertake this study. The second case study was an assessment of the benefits of thermophilic (as opposed to mesophilic operation) for reduced ammonia inhibition, improved stability and gas production in a solids digester at a gelatine production facility. Here, it was predicted that thermophilic operation could not attain either goal to a satisfactory extent. In addition to demonstrating the application of the ADM1 to the two systems, we have also assessed the predictions generated in the case studies in terms of quality and utility. PMID:12926689

  11. [Characteristics of anaerobic sequencing batch reactor for the treatment of high-solids-content waste].

    Science.gov (United States)

    Wang, Zhi-jun; Wang, Wei; Zhang, Xi-hui

    2006-06-01

    Based on the experiments of digestion of thermo-hydrolyzed sewage sludge in both mesophilic and thermophilic anaerobic sequencing batch reactors (ASBRs) with 20, 10, 7.5, 5d hydraulic retention time (HRT), operating characteristics of ASBR for treatment of high-solids-content waste were investigated. ASBR can efficiently accumulates suspended solids and keep high concentration solids, however there exists a "critical point" of ASBR, which means the maximum capability to accumulate suspended solids without negative effects on ASBR stability, and beyond which the performance deteriorates. Under steady condition, ASBR can sustains high solid retention time (SRT) and mean cell retention time (MCRT), the SRT and MCRT is 2.53 approximately 3.73 and 2.03 approximately 3.14 times of hydraulic retention time (HRT) when treating thermo-hydrolyzed sludge, respectively. Therefore, compared to traditional continuous-flow stirred tank reactor (CSTR), the efficiency of ASBR enhances about 7.13% approximately 34.68%.

  12. Optimizing anaerobic digestion by selection of the immobilizing surface for enhanced methane production.

    Science.gov (United States)

    Adu-Gyamfi, Nicholas; Ravella, Sreenivas Rao; Hobbs, Phil J

    2012-09-01

    Maximizing methane production while maintaining an appreciable level of process stability is a crucial challenge in the anaerobic digestion industry. In this study, the role of six parameters: the type of immobilizing supports, loading rate, inoculum levels, C:N ratio, trace nutrients concentrations and mixing rate, on methane production were investigated under thermophilic conditions (55 ± 1°C) with synthetic substrate medium. The immobilizing supports were Silica gel, Sand, Molecular Sieve and Dowex Marathon beads. A Taguchi Design of Experiment (DOE) methodology was employed to determine the effects of different parameters using an L(16) orthogonal array. Overall, immobilizing supports influenced methane production substantially (contributing 61.3% of the observed variation in methane yield) followed by loading rate and inoculum which had comparable influence (17.9% and 17.7% respectively). Optimization improved methane production by 153% (from 183 to 463 ml CH(4)l(-1)d(-1)).

  13. Biogas Production by Anaerobic Digestion of Date PalmPulp Waste

    Directory of Open Access Journals (Sweden)

    Khalidah A. Jaafar

    2010-01-01

    Full Text Available The purpose of this preliminary study is to verify the possibility of using Iraqi Zahdi date palm biomass as a resource for biogas production, methane in particular using thermophilic anaerobic digestion with waste water treatment activated sludge. Moreover, is to investigate the influence of extra nutrients addition to the digestion mixture. Biogas was captured in sealed jars with remote sensing modules connected to computer with integrated program to record the gas pressure continuously. A total gas pressure with 67% Methane was produced from date pulp waste fermentation with a yield of 0.57 Lit for each gram volatile solid of substrate. Addition of 1% yeast extract solution as nutrient increased Methane yield in liters by 5.9%. This is the first time in literature to record biogas production data from Iraqi date palm biomass.

  14. The glucose transport system of the hyperthermophilic anaerobic bacterium Thermotoga neapolitana

    Energy Technology Data Exchange (ETDEWEB)

    Galperin, M.Y.; Noll, K.M.; Romano, A.H. [Univ. of Connecticut, Storrs, CT (United States)

    1996-08-01

    The glucose transport system of the extremely thermophilic anaerobic bacterium Thermotoga neapolitana was studied with the nonmetabolizable glucose analog 2-deoxy-D-glucose (2-DOG). T. neapolitana accumulated 2-DOG against a concentration gradient in an intracellular free sugar pool that was exchangeable with external D-glucose. This active transport of 2-DOG was dependent upon the presence of sodium ion and an external source of energy, such as pyruvate, and was inhibited by arsenate and gramicidin D. There was no phosphoenolpyruvate-dependent phosphorylation of glucose, 2-DOG, or fructose by cell extracts or toluene-treated cells, indicating the absence of a phosphoenolpyruvate:sugar phosphotransferase system. These data indicate that D-glucose is taken up by T.neapolitana via an active transport system that is energized by an ion gradient generated by ATP, derived from substrate-level phosphorylation. 33 refs., 3 figs., 1 tab.

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

    Institute of Scientific and Technical Information of China (English)

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

    2007-01-01

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

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

    Science.gov (United States)

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

    2009-07-01

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

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

    KAUST Repository

    Gonzalez-Gil, Graciela

    2012-12-01

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

  18. 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.

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

    Science.gov (United States)

    Chellapandi, P; Ranjani, J

    2015-09-01

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

  20. Strategies for the dewatering of anaerobic digested biowastes with the regard of the quality of the biowastes and process water. Final report; Strategien zur Entwaesserung von Gaerschlaemmen aus der Bioabfallfermentation unter Beruecksichtigung der Gaerproduktqualitaet und Prozesswasserbelastung. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Dohmann, M.; Buer, T.; Kuepper, R.; Yamamoto, K.

    1998-12-01

    Aim of the research project was to develop strategies for the dewatering of fermentation sludges from the fermentation of biowastes. The quality of the fermentation product as well as the process water load was to be studied in dependence of the flocculation and a downstream-arranged dewatering stage. A membrane filter press and a sieve screw press in semi-technical scale as well as a lab-scale centrifuge were used as dewatering aggregates. The fermentation sludge used for the dewatering experiments came from a semi-technical fermentation plant for biowastes with a total anaerobic reactor volume of 8 m{sup 2}. It turned out that quality and pollution load of the dewatered product and the process water can be decisively influenced by the choice of the flocculant and of the dewatering aggregate. It depends on the separation efficiency whether the resulting waste water can be discharged into the municipal sewer system without expensive pre-treatment (centrifuge, membrane chamber filter press). However, with high separation efficiency the heavy metals adsorbing preferentially at fine particles are kept back together with them, resulting in deterioration of the fermentation product quality. Thus the total dissolved heavy metal load in the digested sludge, which had to be dewatered, was low. Moreover, at least particular constituents should be removed from the process water of a biowaste fermentation plant when dewatering with a sieve screw press before it is reused for mashing the raw biowaste. In this way it can be avoided that heavy metals adsorbed at solid matter concentrate in the fermentation reactor and thus in the fermentation product. (orig.) [Deutsch] Ziel des Untersuchungsvorhabens war es, Strategien fuer die Entwaesserung von Gaerschlaemmen aus der Bioabfallfermentation zu entwickeln. Hierbei sollte insbesondere die Gaerproduktqualitaet als auch die Prozesswasserbelastung in Abhaengigkeit der Flockung und einer nachgeschalteten Entwaesserungsstufe betrachtet

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

    Science.gov (United States)

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

    2014-12-01

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

  2. Genome sequence of the moderately thermophilic sulfur-reducing bacterium Thermanaerovibrio velox type strain (Z-9701(T)) and emended description of the genus Thermanaerovibrio.

    Science.gov (United States)

    Palaniappan, Krishna; Meier-Kolthoff, Jan P; Teshima, Hazuki; Nolan, Matt; Lapidus, Alla; Tice, Hope; Del Rio, Tijana Glavina; Cheng, Jan-Fang; Han, Cliff; Tapia, Roxanne; Goodwin, Lynne A; Pitluck, Sam; Liolios, Konstantinos; Mavromatis, Konstantinos; Pagani, Ioanna; Ivanova, Natalia; Mikhailova, Natalia; Pati, Amrita; Chen, Amy; Rohde, Manfred; Mayilraj, Shanmugam; Spring, Stefan; Detter, John C; Göker, Markus; Bristow, James; Eisen, Jonathan A; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C; Klenk, Hans-Peter; Woyke, Tanja

    2013-10-16

    Thermanaerovibrio velox Zavarzina et al. 2000 is a member of the Synergistaceae, a family in the phylum Synergistetes that is already well-characterized at the genome level. Members of this phylum were described as Gram-negative staining anaerobic bacteria with a rod/vibrioid cell shape and possessing an atypical outer cell envelope. They inhabit a large variety of anaerobic environments including soil, oil wells, wastewater treatment plants and animal gastrointestinal tracts. They are also found to be linked to sites of human diseases such as cysts, abscesses, and areas of periodontal disease. The moderately thermophilic and organotrophic T. velox shares most of its morphologic and physiologic features with the closely related species, T. acidaminovorans. In addition to Su883(T), the type strain of T. acidaminovorans, stain Z-9701(T) is the second type strain in the genus Thermanaerovibrio to have its genome sequence published. Here we describe the features of this organism, together with the non-contiguous genome sequence and annotation. The 1,880,838 bp long chromosome (non-contiguous finished sequence) with its 1,751 protein-coding and 59 RNA genes is a part of the G enomic E ncyclopedia of Bacteria and Archaea project. PMID:24501645

  3. Arsenic, Anaerobes, and Astrobiology

    Science.gov (United States)

    Stolz, J. F.; Oremland, R. S.; Switzer Blum, J.; Hoeft, S. E.; Baesman, S. M.; Bennett, S.; Miller, L. G.; Kulp, T. R.; Saltikov, C.

    2013-12-01

    Arsenic is an element best known for its highly poisonous nature, so it is not something one would associate with being a well-spring for life. Yet discoveries made over the past two decades have delineated that not only are some microbes resistant to arsenic, but that this element's primary redox states can be exploited to conserve energy and support prokaryotic growth ('arsenotrophy') in the absence of oxygen. Hence, arsenite [As(III)] can serve as an electron donor for chemo- or photo-autotrophy while arsenate [As(V)] will serve as an electron acceptor for chemo-heterotrophs and chemo-autotrophs. The phylogenetic diversity of these microbes is broad, encompassing many individual species from diverse taxonomic groups in the Domain Bacteria, with fewer representatives in the Domain Archaea. Speculation with regard to the evolutionary origins of the key functional genes in anaerobic arsenic transformations (arrA and arxA) and aerobic oxidation (aioB) has led to a disputation as to which gene and function is the most ancient and whether arsenic metabolism extended back into the Archaean. Regardless of its origin, robust arsenic metabolism has been documented in extreme environments that are rich in their arsenic content, such as hot springs and especially hypersaline soda lakes associated with volcanic regions. Searles Lake, CA is an extreme, salt-saturated end member where vigorous arsenic metabolism occurs, but there is no detectable sulfate-reduction or methanogenesis. The latter processes are too weak bio-energetically to survive as compared with arsenotrophy, and are also highly sensitive to the abundance of borate ions present in these locales. These observations have implications with respect to the search for microbial life elsewhere in the Solar System where volcanic-like processes have been operative. Hence, because of the likelihood of encountering dense brines in the regolith of Mars (formed by evapo-concentration) or beneath the ice layers of Europa

  4. Anaerobic Digestion of Piggery Waste

    OpenAIRE

    Velsen, van, L.S.

    1981-01-01

    Anaerobic digestion is a biological process by which organic matter is converted to methane and carbon dioxide by microbes in the absence of air (oxygen). In nature, anaerobic conversions occur at all places where organic material accumulates and the supply of oxygen is deficient, e.g. in marshes and lake sediments. Microbial formation of methane also plays a role in the ruminant digestion.In digestion units, the external conditions acting upon the process can be regulated to speed it up as c...

  5. Molecular genetic studies on obligate anaerobic bacteria

    International Nuclear Information System (INIS)

    Molecular genetic studies on obligate anaerobic bacteria have lagged behind similar studies in aerobes. However, the current interest in biotechnology, the involvement of anaerobes in disease and the emergence of antibioticresistant strains have focused attention on the genetics of anaerobes. This article reviews molecular genetic studies in Bacteroides spp., Clostridium spp. and methanogens. Certain genetic systems in some anaerobes differ from those in aerobes and illustrate the genetic diversity among bacteria

  6. Psychrophilic dry anaerobic digestion of dairy cow feces: Long-term operation

    Energy Technology Data Exchange (ETDEWEB)

    Massé, Daniel I., E-mail: Daniel.masse@agr.gc.ca; Cata Saady, Noori M.

    2015-02-15

    Highlights: • Psychrophilic dry anaerobic digestion (PDAD) of cow feces (CF) is feasible. • PDAD of CF is as efficient as mesophilic and thermophilic AD at TCL 21 days. • CF (13–16% TS at OLR 5.0 g TCOD{sub fed} kg{sup −1} inoculum d{sup −1}) yielded 222 ± 27 {sub N}L CH{sub 4} kg{sup −1} VS fed. - Abstract: This paper reports experimental results which demonstrate psychrophilic dry anaerobic digestion of cow feces during long-term operation in sequence batch reactor. Cow feces (13–16% total solids) has been anaerobically digested in 12 successive cycles (252 days) at 21 days treatment cycle length (TCL) and temperature of 20 °C using psychrotrophic anaerobic mixed culture. An average specific methane yield (SMY) of 184.9 ± 24.0, 189.9 ± 27.3, and 222 ± 27.7 {sub N}L CH{sub 4} kg{sup −1} of VS fed has been achieved at an organic loading rate of 3.0, 4.0, and 5.0 g TCOD kg{sup −1} inoculum d{sup −1} and TCL of 21 days, respectively. The corresponding substrate to inoculum ratio (SIR) was 0.39 ± 0.06, 0.48 ± .02, 0.53 ± 0.05, respectively. Average methane production rate of 10 ± 1.4 {sub N}L CH{sub 4} kg{sup −1} VS fed d{sup −1} has been obtained. The low concentration of volatile fatty acids indicated that hydrolysis was the reaction limiting step.

  7. Phenols in anaerobic digestion processes and inhibition of ammonia oxidising bacteria (AOB) in soil

    International Nuclear Information System (INIS)

    This study focuses on the presence of phenols in digestate from seven Swedish large-scale anaerobic digestion processes and their impact on the activity of ammonia oxidising bacteria (AOB) in soil. In addition, the importance of feedstock composition and phenol degradation capacity for the occurrence of phenols in the digestate was investigated in the same processes. The results revealed that the content of phenols in the digestate was related to the inhibition of the activity of AOB in soil (EC5 = 26 μg phenols g-1 d.w. soil). In addition, five pure phenols (phenol, o-, p-, m-cresol and 4-ethylphenol) inhibited the AOB to a similar extent (EC5 = 43-110 μg g-1 d.w. soil). The phenol content in the digestate was mainly dependent on the composition of the feedstock, but also to some extent by the degradation capacity in the anaerobic digestion process. Swine manure in the feedstock resulted in digestate containing higher amounts of phenols than digestate from reactors with less or no swine manure in the feedstock. The degradation capacity of phenol and p-cresol was studied in diluted small-scale batch cultures and revealed that anaerobic digestion at mesophilic temperatures generally exhibited a higher degradation capacity compared to digestion at thermophilic temperature. Although phenol, p-cresol and 4-ethylphenol were quickly degraded in soil, the phenols added with the digestate constitute an environmental risk according to the guideline values for contaminated soils set by the Swedish Environmental Protection Agency. In conclusion, the management of anaerobic digestion processes is of decisive importance for the production of digestate with low amounts of phenols, and thereby little risks for negative effects of the phenols on the soil ecosystem

  8. The phenomenon of granulation of anaerobic sludge.

    NARCIS (Netherlands)

    Hulshoff Pol, L.W.

    1989-01-01

    Successful high-rate anaerobic wastewater treatment can only be accomplished when the slowgrowing anaerobic biomass is efficiently held back in the anaerobic treatment system. This biomass retention can be achieved in various ways including immobilization of the organisms on fixed materials and immo

  9. Viscosity evolution of anaerobic granular sludge

    NARCIS (Netherlands)

    Pevere, A.; Guibaud, G.; Hullebusch, van E.D.; Lens, P.N.L.; Baudu, M.

    2006-01-01

    The evolution of the apparent viscosity at steady shear rate of sieved anaerobic granular sludge (20¿315 ¿m diameter) sampled from different full-scale anaerobic reactors was recorded using rotation tests. The ¿limit viscosity¿ of sieved anaerobic granular sludge was determined from the apparent vis

  10. Kinetics and modeling of anaerobic digestion process

    DEFF Research Database (Denmark)

    Gavala, Hariklia N.; Angelidaki, Irini; Ahring, Birgitte Kiær

    2003-01-01

    Anaerobic digestion modeling started in the early 1970s when the need for design and efficient operation of anaerobic systems became evident. At that time not only was the knowledge about the complex process of anaerobic digestion inadequate but also there were computational limitations. Thus, th...

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

    NARCIS (Netherlands)

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

    2009-01-01

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

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

    NARCIS (Netherlands)

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

    2010-01-01

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

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

    NARCIS (Netherlands)

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

    2007-01-01

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

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

    Science.gov (United States)

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

    2014-05-01

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

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

    NARCIS (Netherlands)

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

    2010-01-01

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

  16. Monitoring and control of anaerobic reactors

    DEFF Research Database (Denmark)

    Pind, Peter Frode; Angelidaki, Irini; Ahring, Birgitte Kiær;

    2003-01-01

    The current status in monitoring and control of anaerobic reactors is reviewed. The influence of reactor design and waste composition on the possible monitoring and control schemes is examined. After defining the overall control structure, and possible control objectives, the possible process...... measurements are reviewed in detail. In the sequel, possible manipulated variables, such as the hydraulic retention time, the organic loading rate, the sludge retention time, temperature, pH and alkalinity are evaluated with respect to the two main reactor types: high-rate and low-rate. Finally, the different...... control approaches that have been used are comprehensively described. These include simple and adaptive controllers, as well as more recent developments such as fuzzy controllers, knowledge-based controllers and controllers based on neural networks....

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

    Energy Technology Data Exchange (ETDEWEB)

    Welker, N.E.

    1991-01-01

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

  18. Characterization of a thermophilic bacteriophage of Geobacillus kaustophilus.

    Science.gov (United States)

    Marks, Timothy J; Hamilton, Paul T

    2014-10-01

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

  19. Ribotyping Identification of Thermophilic Bacterium from Papandayan Crater

    Directory of Open Access Journals (Sweden)

    Akhmaloka

    2006-05-01

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

  20. 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.

  1. 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

  2. The bioleaching of different sulfide concentrates using thermophilic bacteria

    Science.gov (United States)

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

    1995-05-01

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

  3. Anaerobic Metabolism: Linkages to Trace Gases and Aerobic Processes

    Science.gov (United States)

    Megonigal, J. P.; Hines, M. E.; Visscher, P. T.

    2003-12-01

    's surface area, they have a profound influence on the biogeochemistry of the planet. This is evident from the observation that the O2 and CH4 content of Earth's atmosphere are in extreme disequilibrium (Sagan et al., 1993). The combination of high aerobic primary production and anoxic sediments provided the large deposits of fossil fuels that have become vital and contentious sources of energy for modern industrialized societies. Anaerobic metabolism is responsible for the abundance of N2 in the atmosphere; otherwise N2-fixing bacteria would have consumed most of the N2 pool long ago (Schlesinger, 1997). Anaerobic microorganisms are common symbionts of termites, cattle, and many other animals, where they aid digestion. Nutrient and pollutant chemistry are strongly modified by the reduced conditions that prevail in wetland and aquatic ecosystems.This review of anaerobic metabolism emphasizes aerobic oxidation, because the two processes cannot be separated in a complete treatment of the topic. It is process oriented and highlights the fascinating microorganisms that mediate anaerobic biogeochemistry. We begin this review with a brief discussion of CO2 assimilation by autotrophs, the source of most of the reducing power on Earth, and then consider the biological processes that harness this potential energy. Energy liberation begins with the decomposition of organic macromolecules to relatively simple compounds, which are simplified further by fermentation. Methanogenesis is considered next because CH4 is a product of acetate fermentation, and thus completes the catabolism of organic matter, particularly in the absence of inorganic electron acceptors. Finally, the organisms that use nitrogen, manganese, iron, and sulfur for terminal electron acceptors are considered in order of decreasing free-energy yield of the reactions.

  4. Investigation of factors influencing biogas production in a large-scale thermophilic municipal biogas plant

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, Agnes; Jerome, Valerie; Freitag, Ruth [Bayreuth Univ. (Germany). Chair for Process Biotechnology; Burghardt, Diana; Likke, Likke; Peiffer, Stefan [Bayreuth Univ. (Germany). Dept. of Hydrology; Hofstetter, Eugen M. [RVT Process Equipment GmbH, Steinwiesen (Germany); Gabler, Ralf [BKW Biokraftwerke Fuerstenwalde GmbH, Fuerstenwalde (Germany)

    2009-10-15

    A continuously operated, thermophilic, municipal biogas plant was observed over 26 months (sampling twice per month) in regard to a number of physicochemical parameters and the biogas production. Biogas yields were put in correlation to parameters such as the volatile fatty acid concentration, the pH and the ammonium concentration. When the residing microbiota was classified via analysis of the 16S rRNA genes, most bacterial sequences matched with unidentified or uncultured bacteria from similar habitats. Of the archaeal sequences, 78.4% were identified as belonging to the genus Methanoculleus, which has not previously been reported for biogas plants, but is known to efficiently use H{sub 2} and CO{sub 2} produced by the degradation of fatty acids by syntrophic microorganisms. In order to further investigate the influence of varied amounts of ammonia (2-8 g/L) and volatile fatty acids on biogas production and composition (methane/CO{sub 2}), laboratory scale satellite experiments were performed in parallel to the technical plant. Finally, ammonia stripping of the process water of the technical plant was accomplished, a measure through which the ammonia entering the biogas reactor via the mash could be nearly halved, which increased the energy output of the biogas plant by almost 20%. (orig.)

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    OpenAIRE

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

    1988-01-01

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

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

    Science.gov (United States)

    Falkowski, J

    1978-08-01

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

  9. Oxygen Effects in Anaerobic Digestion

    Directory of Open Access Journals (Sweden)

    Deshai Botheju

    2009-10-01

    Full Text Available Interaction of free oxygen in bio-gasification is a sparsely studied area, apart from the common argument of oxygen being toxic and inhibitory for anaerobic micro-cultures. Some studies have, however, revealed increased solubilisation of organic matter in the presence of some free oxygen in anaerobic digestion. This article analyses these counterbalancing phenomena with a mathematical modelling approach using the widely accepted biochemical model ADM 1. Aerobic oxidation of soluble carbon and inhibition of obligatory anaerobic organisms are modelled using standard saturation type kinetics. Biomass dependent first order hydrolysis kinetics is used to relate the increased hydrolysis rate with oxygen induced increase in biomass growth. The amended model, ADM 1-Ox (oxygen, has 25 state variables and 22 biochemical processes, presented in matrix form. The computer aided simulation tool AQUASIM 2.1 is used to simulate the developed model. Simulation predictions are evaluated against experimental data obtained using a laboratory batch test array comprising miniature anaerobic bio-reactors of 100 ml total volume each, operated under different initial air headspaces giving rise to the different oxygen loading conditions. The reactors were initially fed with a glucose solution and incubated at 35 Celsius, for 563 hours. Under the oxygen load conditions of 22, 44 and 88 mg/L, the ADM1-Ox model simulations predicted the experimental methane potentials quite adequately. Both the experimental data and the simulations suggest a linear reduction of methane potential with respect to the increase in oxygen load within this range.

  10. Anaerobic Treatment of Methanolic Wastes

    NARCIS (Netherlands)

    Lettinga, G.; Geest, van der A.Th.; Hobma, S.W.; Laan, van der J.B.R.

    1979-01-01

    Although it is well known that methanol can be fermented directly by a specific species of methane bacteria, viz. Methanosarcina barkeri, until now little information was available about the effect of important environmental factors on the anaerobic fermentation of methanol. As methanol can be the m

  11. Fate of 17β-estradiol in anaerobic lagoon digesters.

    Science.gov (United States)

    Hakk, Heldur; Sikora, Lawrence; Casey, Francis X M; Larsen, Gerald L

    2014-03-01

    The fate of [C]17β-estradiol ([C]E2) was monitored for 42 d in triplicate 10-L anaerobic digesters. Total radioactive residues decreased rapidly in the liquid layer of the digesters and reached a steady-state value of 22 to 26% of the initial dose after 5 d. High-performance liquid chromatography and liquid chromatography-tandem mass spectrometry analyses of the liquid layer of the anaerobic digesters indicated a rapid degradation of E2 to estrone (E1), which readily adsorbed to the sludge layer subsequent to its formation. Estrone was the predominant steroid identified under anaerobic digestion in the liquid layer or sorbed to sludge at 42 d. Methane formation represented 11.1 ± 5.7% of the initial E2 fortification with 0.3 to 0.5% of the starting E2 mineralized to carbon dioxide. Maximum [C]methane production appeared between Days 4 and 7. An estimate of estrogenicity of the final product based on reported estrogen equivalents for E1 and E2 was 2% of the original in active digesters. Anaerobic digestion of swine waste has several management benefits; moreover, this study demonstrated that it reduces the potential of environmental release of estrogens, which are known endocrine disruptors. PMID:25602671

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

    Science.gov (United States)

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

    2012-01-01

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

  13. Thermoanaerobacter pentosaceus sp. nov., an anaerobic, extreme thermophilic, high ethanol-yielding bacterium isolated from household waste

    DEFF Research Database (Denmark)

    Tomás, Ana Faria; Karakashev, Dimitar Borisov; Angelidaki, Irini

    2013-01-01

    and xylose, but not cellulose, Avicel®, mannitol, inositol, glycerol, acetate, lactate, ethanol, butanol or peptone. Ethanol was the major fermentation product and a maximum yield of 1.39 mol of ethanol per mol xylose was achieved when sulphite was added to the cultivation medium. Thiosulphite...

  14. Thermophilic anaerobic co-digestion of oil palm empty fruit bunches with palm oil mill effluent for efficient biogas production

    DEFF Research Database (Denmark)

    O-Thong, Sompong; Boe, Kanokwan; Angelidaki, Irini

    2012-01-01

    The effect of pretreatment methods for improved biodegradability and biogas production of oil palm empty fruit bunches (EFB) and its co-digestion with palm oil mill effluent (POME) was investigated. The maximum methane potential of POME was 502mL CH4/gVS-added corresponding to 33.2m3 CH4/ton POME...

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

    DEFF Research Database (Denmark)

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

    2015-01-01

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

  16. Thermoanaerobacter mathranii sp. nov., an ethanol-producing, extremely thermophilic anaerobic bacterium from a hot spring in Iceland

    DEFF Research Database (Denmark)

    Larsen, L.; Nielsen, P.; Ahring, B.K.

    1997-01-01

    occurred in the range of 50-75 degrees C. The pH range for growth was 4.7-8.8, with an optimum at pH 7.0. Strain A3 was sensitive to tetracycline, chloramphenicol, penicillin G. neomycin, and vancomycin at 100 mg/l but was not sensitive to chloramphenicol and neomycin at 10 mg/l, which indicates...

  17. Survival of weed seeds and animal parasites as affected by anaerobic digestion at meso- and thermophilic conditions

    DEFF Research Database (Denmark)

    Johansen, Anders; Bangsø Nielsen, Henrik; Hansen, Christian M.;

    2013-01-01

    ) was very clear as complete mortality, irrespective of weed species, was reached after less than 2 days. At mesophilic conditions, seeds of Avena fatua, Sinapsis arvensis, Solidago canadensis had completely lost germination ability, while Brassica napus, Fallopia convolvulus and Amzinckia micrantha still...

  18. Methanocella conradii sp. nov., a thermophilic, obligate hydrogenotrophic methanogen, isolated from Chinese rice field soil.

    Directory of Open Access Journals (Sweden)

    Zhe Lü

    Full Text Available BACKGROUND: Methanocellales contributes significantly to anthropogenic methane emissions that cause global warming, but few pure cultures for Methanocellales are available to permit subsequent laboratory studies (physiology, biochemistry, etc.. METHODOLOGY/PRINCIPAL FINDINGS: By combining anaerobic culture and molecular techniques, a novel thermophilic methanogen, strain HZ254(T was isolated from a Chinese rice field soil located in Hangzhou, China. The phylogenetic analyses of both the 16S rRNA gene and mcrA gene (encoding the α subunit of methyl-coenzyme M reductase confirmed its affiliation with Methanocellales, and Methanocella paludicola SANAE(T was the most closely related species. Cells were non-motile rods, albeit with a flagellum, 1.4-2.8 µm long and by 0.2-0.3 µm in width. They grew at 37-60 °C (optimally at 55 °C and salinity of 0-5 g NaCl l(-1 (optimally at 0-1 g NaCl l(-1. The pH range for growth was 6.4-7.2 (optimum 6.8. Under the optimum growth condition, the doubling time was 6.5-7.8 h, which is the shortest ever observed in Methanocellales. Strain HZ254(T utilized H(2/CO(2 but not formate for growth and methane production. The DNA G+C content of this organism was 52.7 mol%. The sequence identities of 16S rRNA gene and mcrA gene between strain HZ254(T and SANAE(T were 95.0 and 87.5% respectively, and the genome based Average Nucleotide Identity value between them was 74.8%. These two strains differed in phenotypic features with regard to substrate utilization, possession of a flagellum, doubling time (under optimal conditions, NaCl and temperature ranges. Taking account of the phenotypic and phylogenetic characteristics, we propose strain HZ254(T as a representative of a novel species, Methanocella conradii sp. nov. The type strain is HZ254(T ( = CGMCC 1.5162(T = JCM 17849(T = DSM 24694(T. CONCLUSIONS/SIGNIFICANCE: Strain HZ254(T could potentially serve as an excellent laboratory model for studying Methanocellales due to its

  19. Anaerobic granular sludge and biofilm reactors

    DEFF Research Database (Denmark)

    Skiadas, Ioannis V.; Gavala, Hariklia N.; Schmidt, Jens Ejbye;

    2003-01-01

    by the immobilization of the biomass, which forms static biofilms, particle-supported biofilms, or granules depending on the reactor's operational conditions. The advantages of the high-rate anaerobic digestion over the conventional aerobic wastewater treatment methods has created a clear trend for the change......-rate anaerobic treatment systems based on anaerobic granular sludge and biofilm are described in this chapter. Emphasis is given to a) the Up-flow Anaerobic Sludge Blanket (UASB) systems, b) the main characteristics of the anaerobic granular sludge, and c) the factors that control the granulation process...

  20. Anaerobic treatment of cassava stillage for hydrogen and methane production in continuously stirred tank reactor (CSTR) under high organic loading rate (OLR)

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Gang; Xie, Li; Zou, Zhonghai; Wang, Wen; Zhou, Qi [Key Laboratory of Yangtze River Water Environment, Ministry of Education (Tongji University), UNEP-Tongji, Tongji University, Siping Road No. 1239, Shanghai 200092 (China); Shim, Hojae [Department of Civil and Environmental Engineering, Faculty of Science and Technology, University of Macau, Macau SAR 999078 (China)

    2010-11-15

    Anaerobic hydrogen and methane production from cassava stillage in continuously stirred tank reactor (CSTR) were investigated in this study. Results showed that the heat-pretreatment of inoculum did not enhance hydrogen yield compared to raw inoculum under mesophilic condition after continuous operation. However, the hydrogen yield increased from about 14 ml H{sub 2}/gVS under mesophilic condition to 69.6 ml H{sub 2}/gVS under thermophilic condition due to the decrease of propionate concentration and inhibition of homoacetogens. Therefore, temperature was demonstrated to be more important than pretreatment of inoculum to enhance the hydrogen production. Under high organic loading rate (OLR) (>10 gVS/(L.d)), the two-phase thermophilic CSTR for hydrogen and methane production was stable with hydrogen and methane yields of 56.6 mlH{sub 2}/gVS and 249 mlCH{sub 4}/gVS. The one-phase thermophilic CSTR for methane production failed due to the accumulation of both acetate and propionate, leading to the pH lower than 6. Instead of propionate alone, the accumulations of both acetate and propionate were found to be related to the breakdown of methane reactor. (author)

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

    Science.gov (United States)

    Tominaga, Yurie; Ohshiro, Takashi; Suzuki, Hirokazu

    2016-05-01

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

  2. Effect of incubation conditions on anaerobic susceptibility testing results.

    OpenAIRE

    Murray, P R; Niles, A C

    1982-01-01

    We determined the effect of performing antimicrobial susceptibility tests in five different anaerobic incubation systems: GasPak jar, large GasPak jar, evacuated-gassed anaerobic jar, anaerobic chamber, and Bio-Bag. Growth of the anaerobes was equivalent in all five incubation systems. The results of testing 38 anaerobes against 11 antimicrobial agents were comparable for the anaerobic jars and anaerobic chamber. However, discordant results were observed for metronidazole and cefamandole test...

  3. Anaerobic digestion of solid biomass and biowaste

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-07-01

    Within the International Trade Fair for Biogas Plant Technology from 23rd to 24th February, 2012 in Berlin, the following lectures were held: (1) Presentation and results of the EU project 24biomass'' (Claudia Lutsyuk); (2) The Polish biogas market (Tomasz Surowiec); (3) Presence and future of the biogas sector in Poland - EBE project (Eugeniusz Jedrysik); (4) Modern biogas generation in Poland - Case studies of the company Poldanor (Jens Bo Holm-Nielsen); (5) Low space requirement - The challenge in the integration of biogas plants in existing composting facilities - examples from real life (Michael Oertig); (6) Integration of biogas plants in composting facilities by partial-flow fermentation (Bruno Mattheeuws); (7) The significance of an efficient removal of foreign matter from biomass before fermentation in a waste incinerator for municipal wastes (Stephan Schulte); (8) Sustainable enhancement of the anaerobic degradation and increase of the biogas production by means of ultrasonic treatment - examples from real life (Silvana Velten); (9) Cultivation of energy plants on sandy soils in the northeastern part of Germany (Gunter Ebel); (10) Topinambur, a new sustainable energy crop for biogas generation (Vito Pignatelli); (11) Potential of biogas generation from reed (Vilis Dubrovskis); (12) Biogas generation from maize straw - a new procedure of harvesting and processing (Thomas Amon); (13) Generation of biogas by cofermentation of pig manure and grass silage: a pilot study (Ximmin Zhan); (14) Thermophilic dry fermentation of poultry litter and energy crops for the generation of biogas, organic fertilizer and protection of water resources from environmental damages in the Mid-Atlantic region of the USA (John Intersoll); (15) Energetic utilisation of horse manure (Saskia Oldenburg); (16) Realization of the greatest and most modern Hungarian biogas plant in Szarvas (Ludwig Dinkloh); (16) Biogas in Russia - The investment program of the cooperation &apos

  4. Biohydrogen production from dual digestion pretreatment of poultry slaughterhouse sludge by anaerobic self-fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Sittijunda, Sureewan [Department of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002 (Thailand); Reungsang, Alissara [Department of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002 (Thailand); Fermentation Research Center for Value Added Agricultural Products, Khon Kaen University, Khon Kaen 40002 (Thailand); O-thong, Sompong [Department of Biology, Faculty of Science, Thaksin University, Patthalung 93110 (Thailand)

    2010-12-15

    Poultry slaughterhouse sludge from chicken processing wastewater treatment plant was tested for their suitability as a substrate and inoculum source for fermentation hydrogen production. Dual digestion of poultry slaughterhouse sludge was employed to produce hydrogen by batch anaerobic self-fermentation without any extra-seeds. The sludge (5% TS) was dual digested by aerobic thermophilic digestion at 55 C with the varying retention time before using as substrate in anaerobic self-fermentation. The best digestion time for enriching hydrogen-producing seeds was 48 h as it completely repressed methanogenic activity and gave the maximum hydrogen yield of 136.9 mL H{sub 2}/g TS with a hydrogen production rate of 2.56 mL H{sub 2}/L/h. The hydrogen production of treated sludge at 48 h (136.9 mL H{sub 2}/g TS) was 15 times higher than that of the raw sludge (8.83 mL H{sub 2}/g TS). With this fermentation process, tCOD value in the activated sludge could be reduced up to 30%. (author)

  5. Anaerobic digestion technologies for closing the domestic water, carbon and nutrient cycles.

    Science.gov (United States)

    Hammes, F; Kalogo, Y; Verstraete, W

    2000-01-01

    Sustainable wastewater treatment requires that household wastewater is collected and treated separately from industrial wastewater and rainwater run-offs. This separate treatment is, however, still inadequate, as more than 70% of the nutrients and much of the chemical oxygen demand (COD) and potential pathogens of a domestic sewage system are confined to the few litres of black water (faeces, urine and toilet water). Whilst grey water can easily be filter treated and re-used for secondary household purposes, black water requires more intensive treatment due to its high COD and microbial (pathogens) content. Recently developed vacuum/dry toilets produce a nutrient rich semi-solid waste stream, which, with proper treatment, offers the possibility of nutrient, carbon, water and energy recovery. This study investigates the terrestrial applicability of Life Support System (LSS) concepts as a framework for future domestic waste management. The possibilities of treating black water together with other types of human-generated solid waste (biowastes/mixed wastes) in an anaerobic reactor system at thermophilic conditions, as well as some post treatment alternatives for product recovery and re-use, are considered. Energy can partially be recovered in the form of biogas produced during anaerobic digestion. The system is investigated in the form of theoretical mass balances, together with an assessment of the current feasibility of this technology and other post-treatment alternatives. PMID:11381993

  6. Application of acidic thermal treatment for one- and two-stage anaerobic digestion of sewage sludge.

    Science.gov (United States)

    Takashima, M; Tanaka, Y

    2010-01-01

    The effectiveness of acidic thermal treatment (ATT) was examined in a 106-day continuous experiment, when applied to one- or two-stage anaerobic digestion of sewage sludge (4.3% TS). The ATT was performed at 170 °C and pH 5 for 1 hour (sulfuric acid for lowering pH). The one-stage process was mesophilic at 20 days hydraulic retention time (HRT), and incorporated the ATT as pre-treatment. The two-stage process consisted of a thermophilic digester at 5 days HRT and a mesophilic digester at 15 days HRT, and incorporated the ATT as interstage-treatment. On average, VSS reduction was 48.7% for the one-stage control, 65.8% for the one-stage ATT, 52.7% for the two-stage control and 67.6% for the two-stage ATT. Therefore, VSS reduction was increased by 15-17%, when the ATT was combined in both one- and two-stage processes. In addition, the dewaterability of digested sludge was remarkably improved, and phosphate release was enhanced. On the other hand, total methane production did not differ significantly, and color generation was noted in the digested sludge solutions with the ATT. In conclusion, the anaerobic digestion with ATT can be an attractive alternative for sludge reduction, handling, and phosphorus recovery. PMID:21099053

  7. Anaerobic biofilm reactors for dark fermentative hydrogen production from wastewater: A review.

    Science.gov (United States)

    Barca, Cristian; Soric, Audrey; Ranava, David; Giudici-Orticoni, Marie-Thérèse; Ferrasse, Jean-Henry

    2015-06-01

    Dark fermentation is a bioprocess driven by anaerobic bacteria that can produce hydrogen (H2) from organic waste and wastewater. This review analyses a relevant number of recent studies that have investigated dark fermentative H2 production from wastewater using two different types of anaerobic biofilm reactors: anaerobic packed bed reactor (APBR) and anaerobic fluidized bed reactor (AFBR). The effect of various parameters, including temperature, pH, carrier material, inoculum pretreatment, hydraulic retention time, substrate type and concentration, on reactor performances was investigated by a critical discussion of the results published in the literature. Also, this review presents an in-depth study on the influence of the main operating parameters on the metabolic pathways. The aim of this review is to provide to researchers and practitioners in the field of H2 production key elements for the best operation of the reactors. Finally, some perspectives and technical challenges to improve H2 production were proposed. PMID:25746594

  8. Characteristics of hydrogen and methane production from cornstalks by an augmented two- or three-stage anaerobic fermentation process.

    Science.gov (United States)

    Lu, Yuan; Lai, Qiheng; Zhang, Chong; Zhao, Hongxin; Ma, Kun; Zhao, Xuebing; Chen, Hongzhang; Liu, Dehua; Xing, Xin-Hui

    2009-06-01

    This paper presents the co-production of hydrogen and methane from cornstalks by a two- or three-stage anaerobic fermentation process augmented with effective artificial microbial community. Two-stage fermentation by using the anaerobic sludge and DGGE analysis showed that effective and stable strains should be introduced into the system. We introduced Enterobacter aerogens or Clostridium paraputrificum into the hydrogen stage, and C. paraputrificum was proven to be more effective. In the three-stage process consisting of the improved hydrolysis, hydrogen and methane production stages, the highest soluble sugars (0.482 kg/kg cornstalks) were obtained after the introduction of Clostridium thermocellum in the hydrolysis stage, under the thermophilic (55 degrees C) and acidic (pH 5.0) conditions. Hydrolysates from 1 kg of cornstalks could produce 2.61 mol (63.7 l) hydrogen by augmentation with C. paraputrificum and 4.69 mol (114.6 l) methane by anaerobic granular sludge, corresponding to 54.1% energy recovery.

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

    Institute of Scientific and Technical Information of China (English)

    YANG Bo; OUYANG Jianping; AO Jingqun; CHEN Xinhua

    2009-01-01

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

  10. Anaerobic digestion of solid material

    DEFF Research Database (Denmark)

    Vavilin, V.A.; Lokshina, L.Y.; Flotats, X.;

    2007-01-01

    A new multidimensional (3 and 2D) anaerobic digestion model for cylindrical reactor with non-uniform influent concentration distributions was developed to study the way in which mixing intensity affects the efficiency of continuous-flow anaerobic digestion. Batch experiments reported and simulated...... earlier by Vavilin and Angelidaki (2005) were used to modernize a kinetic scheme and to obtain the corresponding kinetic coefficients. In the new models, hydrolytic microorganisms were included using Contois kinetics for the hydrolysis/acidogenesis degradation of municipal solid waste (MSW). Monod...... kinetics was applied for description of methanogenesis. Both hydrolytic and methanogenic microorganisms were assumed to be inhibited by high volatile fatty acids (VFA) concentration. According to the new distributed models, the mixing level reduction expressed by increasing dimensionless Peclet number may...

  11. Anaerobic procedures of wastewater treatment

    OpenAIRE

    Zupančič, Tadeja

    2013-01-01

    Highly polluted wastewater is formed in dairies, pig farms and slaughterhouses. Before released into watercourses, wastewater should be properly processed with different treatment procedures in wastewater treatment plants. The thesis deals with the descriptions of mechanical, physical and chemical, and biological wastewater treatment procedures and the description of the factors which affect the reactions in wastewater treatment plants. I give special emphasis on anaerobic wastewater treatmen...

  12. 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

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

    Directory of Open Access Journals (Sweden)

    De Felice Maurilio

    2002-04-01

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

  14. Optimization and microbial community analysis for production of biohydrogen from palm oil mill effluent by thermophilic fermentative process

    Energy Technology Data Exchange (ETDEWEB)

    Prasertsan, Poonsuk [Department of Industrial Biotechnology, Faculty of Agro-Industry, Prince of Songkla University, Songkhla 90112 (Thailand); Palm Oil Product and Technology Research Center, Faculty of Agro-Industry, Prince of Songkla University, Songkhla 90112 (Thailand); O-Thong, Sompong [Department of Biology, Faculty of Science, Thaksin University, Phatthalung 93110 (Thailand); Birkeland, Nils-Kaare [Department of Biology and Centre for Geobiology, University of Bergen, P.O. Box 7800, N-5020 Bergen (Norway)

    2009-09-15

    The optimum values of hydraulic retention time (HRT) and organic loading rate (OLR) of an anaerobic sequencing batch reactor (ASBR) for biohydrogen production from palm oil mill effluent (POME) under thermophilic conditions (60 C) were investigated in order to achieve the maximum process stability. Microbial community structure dynamics in the ASBR was studied by denaturing gradient gel electrophoresis (DGGE) aiming at improved insight into the hydrogen fermentation microorganisms. The optimum values of 2-d HRT with an OLR of 60 gCOD l{sup -1} d{sup -1} gave a maximum hydrogen yield of 0.27 l H{sub 2} g COD{sup -1} with a volumetric hydrogen production rate of 9.1 l H{sub 2} l{sup -1} d{sup -1} (16.9 mmol l{sup -1}h{sup -1}). The hydrogen content, total carbohydrate consumption, COD (chemical oxygen demand) removal and suspended solids removal were 55 {+-} 3.5%, 92 {+-} 3%, 57 {+-} 2.5% and 78 {+-} 2%, respectively. Acetic acid and butyric acid were the major soluble end-products. The microbial community structure was strongly dependent on the HRT and OLR. DGGE profiling illustrated that Thermoanaerobacterium spp., such as Thermoanaerobacterium thermosaccharolyticum and Thermoanaerobacterium bryantii, were dominant and probably played an important role in hydrogen production under the optimum conditions. The shift in the microbial community from a dominance of T. thermosaccharolyticum to a community where also Caloramator proteoclasticus constituted a major component occurred at suboptimal HRT (1 d) and OLR (80 gCOD l{sup -1} d{sup -1}) conditions. The results showed that the hydrogen production performance was closely correlated with the bacterial community structure. This is the first report of a successful ASBR operation achieving a high hydrogen production rate from real wastewater (POME). (author)

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

    Directory of Open Access Journals (Sweden)

    Hriush Adhikari

    2015-09-01

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

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

    Institute of Scientific and Technical Information of China (English)

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

    2008-01-01

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

  17. 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.

  18. Potential for anaerobic conversion of xenobiotics

    DEFF Research Database (Denmark)

    Mogensen, Anders Skibsted; Dolfing, J.; Haagensen, Frank;

    2003-01-01

    This review covers the latest research on the anaerobic biodegradation of aromatic xenobiotic compounds, with emphasis on surfactants, polycyclic aromatic hydrocarbons, phthalate esters, polychlorinated biphenyls, halogenated phenols, and pesticides. The versatility of anaerobic reactor systems...... regarding the treatment of xenobiotics is shown with the focus on the UASB reactor, but the applicability of other reactor designs for treatment of hazardous waste is also included. Bioaugmentation has proved to be a viable technique to enhance a specific activity in anaerobic reactors and recent research...

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

    Science.gov (United States)

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

    2014-07-01

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

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

    Science.gov (United States)

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

    2016-03-01

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