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Sample records for anaerobic thermophiles final

  1. 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

  2. ANAEROBIC BIODEGRADATION OF A BIODEGRADABLE MATERIAL UNDER ANAEROBIC - THERMOPHILIC DIGESTION

    Directory of Open Access Journals (Sweden)

    RICARDO CAMACHO-MUÑOZ

    2014-12-01

    Full Text Available This paper dertermined the anaerobic biodegradation of a polymer obtained by extrusion process of native cassava starch, polylactic acid and polycaprolactone. Initially a thermophilic - methanogenic inoculum was prepared from urban solid waste. The gas final methane concentration and medium’s pH reached values of 59,6% and 7,89 respectively. The assay assembly was carried out according ASTM D5511 standard. The biodegradation percent of used materials after 15 day of digestion were: 77,49%, 61,27%, 0,31% for cellulose, sample and polyethylene respectively. Due cellulose showed biodegradation levels higher than 70% it’s deduced that the inoculum conditions were appropriate. A biodegradation level of 61,27%, 59,35% of methane concentration in sample’s evolved gas and a medium’s finale pH of 7,71 in sample’s vessels, reveal the extruded polymer´s capacity to be anaerobically degraded under thermophilic- high solid concentration conditions.

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

    Science.gov (United States)

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

    2015-02-01

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

  4. 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

  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

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

  6. Status on Science and Application of Thermophilic Anaerobic Digestion

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær

    1994-01-01

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

  7. Anaerobic thermophilic culture-system

    Energy Technology Data Exchange (ETDEWEB)

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

    1981-04-14

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

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

    Science.gov (United States)

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

    2010-12-01

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

  9. Thermophilic anaerobic digestion of Lurgi coal gasification wastewater in a UASB reactor

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.; Ma, W.C.; Han, H.J.; Li, H.Q.; Yuan, M. [Harbin Institute of Technology, Harbin (China)

    2011-02-15

    Lurgi coal gasification wastewater (LCGW) is a refractory wastewater, whose anaerobic treatment has been a severe problem due to its toxicity and poor biodegradability. Using a mesophilic (35 {+-} 2{sup o}C) reactor as a control, thermophilic anaerobic digestion (55 {+-} 2{sup o}C) of LCGW was investigated in a UASB reactor. After 120 days of operation, the removal of COD and total phenols by the thermophilic reactor could reach 50-55% and 50-60% respectively, at an organic loading rate of 2.5 kg COD/(m{sup 3} d) and HRT of 24h: the corresponding efficiencies were both only 20-30% in the mesophilic reactor. After thermophilic digestion, the wastewater concentrations of the aerobic effluent COD could reach below 200 mg/L compared with around 294 mg/L if mesophilic digestion was done and around 375 mg/L if sole aerobic pre-treatment was done. The results suggested that thermophilic anaerobic digestion improved significantly both anaerobic and aerobic biodegradation of LCGW.

  10. Mesophilic and thermophilic anaerobic digestion of biologically pretreated abattoir wastewaters in an upflow anaerobic filter

    International Nuclear Information System (INIS)

    Gannoun, H.; Bouallagui, H.; Okbi, A.; Sayadi, S.; Hamdi, M.

    2009-01-01

    The hydrolysis pretreatment of abattoir wastewaters (AW), rich in organic suspended solids (fats and protein) was studied in static and stirred batch reactors without aeration in the presence of natural microbial population acclimated in a storage tank of AW. Microbial analysis showed that the major populations which contribute to the pretreatment of AW belong to the genera Bacillus. Contrary to the static pretreatment, the stirred conditions favoured the hydrolysis and solubilization of 80% of suspended matter into soluble pollution. The pretreated AW, in continuous stirred tank reactor (CSTR) at a hydraulic retention time (HRT) of 2 days, was fed to an upflow anaerobic filter (UAF) at an HRT of 2 days. The performance of anaerobic digestion of biologically pretreated AW was examined under mesophilic (37 deg. C) and thermophilic (55 deg. C) conditions. The shifting from a mesophilic to a thermophilic environment in the UAF was carried out with a short start-up of thermophilic condition. The UAF ran at organic loading rates (OLRs) ranging from 0.9 to 6 g COD/L d in mesophilic conditions and at OLRs from 0.9 to 9 g COD/L d in thermophilic conditions. COD removal efficiencies of 80-90% were achieved for OLRs up to 4.5 g COD/L d in mesophilic conditions, while the highest OLRs i.e. 9 g COD/L d led to efficiencies of 70-72% in thermophilic conditions. The biogas yield in thermophilic conditions was about 0.32-0.45 L biogas/g of COD removed for OLRs up to 4.5 g COD/L d. For similar OLR, the UAF in mesophilic conditions showed lower percentage of methanization. Mesophilic anaerobic digestion has been shown to destroy pathogens partially, whereas the thermophilic process was more efficient in the removal of indicator microorganisms and pathogenic bacteria at different organic loading rates.

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

    NARCIS (Netherlands)

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

    2002-01-01

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

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Science.gov (United States)

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

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

  14. Performance of thermophilic anaerobic digesters using inoculum mixes with enhanced methanogenic diversity

    KAUST Repository

    Ghanimeh, Sophia; El-Fadel, Mutasem; Saikaly, Pascal

    2017-01-01

    Reportedly, various mixes of seeds were quasi-randomly selected to startup anaerobic digesters. In contrast, this study examines the impact of inoculating thermophilic anaerobic digesters with a designed mix of non-acclimated seeds based

  15. 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

    Hydrogen and methane production from desugared molasses by a two‐stage thermophilic anaerobic process was investigated in a series of two up‐flow anaerobic sludge blanket (UASB) reactors. The first reactor that was dominated with hydrogen‐producing bacteria of Thermoanaerobacterium thermosaccharo......Hydrogen and methane production from desugared molasses by a two‐stage thermophilic anaerobic process was investigated in a series of two up‐flow anaerobic sludge blanket (UASB) reactors. The first reactor that was dominated with hydrogen‐producing bacteria of Thermoanaerobacterium...... molasses. Furthermore, the mixed gas with a volumetric content of 16.5% H2, 38.7% CO2, and 44.8% CH4, containing approximately 15% energy by hydrogen is viable to be bio‐hythane....

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

    DEFF Research Database (Denmark)

    Georgieva, Tania I.

    2006-01-01

    and xylose and to tolerate the inhibitory compounds present in lignocellulosic hydrolysates is therefore apparent. Several thermophilic anaerobic xylan degrading bacteria from our culture collection (EMB group at BioCentrum-DTU) have been screened for a potential ethanol producer from hemicellulose...... hydrolysates, and out of the screening test, one particular strain (A10) was selected for the best performance. The strain was morphologically and physiologically characterized as Thermoanaerobacter mathranii strain A10. Unlike other thermophilic anaerobic bacteria, the wild-type strain Thermoanaerobacter...... Thermoanaerobacter BG1L1 was further studied. The experiments were carried out in a continuous immobilized reactor system (a fluidized bed reactor), which is likely to be the process design configuration for xylose fermentation in a Danish biorefinery concept for production of fuel ethanol. The immobilization...

  17. Azo dye reduction by mesophilic and thermophilic anaerobic consortia

    NARCIS (Netherlands)

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

    2005-01-01

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

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

    Science.gov (United States)

    Colleran, E; Pender, S

    2002-01-01

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

  19. In situ identification of the synthrophic protein fermentative Coprothermobacter spp. involved in the thermophilic anaerobic digestion process.

    Science.gov (United States)

    Gagliano, Maria Cristina; Braguglia, Camilla Maria; Rossetti, Simona

    2014-09-01

    Thermophilic bacteria have recently attracted great attention because of their potential application in improving different biochemical processes such as anaerobic digestion of various substrates, wastewater treatment or hydrogen production. In this study we report on the design of a specific 16S rRNA-targeted oligonucleotide probe for detecting members of Coprothermobacter genus characterized by a strong protease activity to degrade proteins and peptides. The newly designed CTH485 probe and helper probes hCTH429 and hCTH439 were optimized for use in fluorescence in situ hybridization (FISH) on thermophilic anaerobic sludge samples. In situ probing revealed that thermo-adaptive mechanisms shaping the 16S rRNA gene may affect the identification of thermophilic microorganisms. The novel developed FISH probe extends the possibility to study the widespread thermophilic syntrophic interaction of Coprothermobacter spp. with hydrogenotrophic methanogenic archaea, whose establishment is a great benefit for the whole anaerobic system. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  20. 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

    Changes in the redox metabolism in the anaerobic, extremely thermophilic, hydrogen-forming bacterium Caldicellulosiruptor saccharolyticus were probed for the first time in vivo using mediated amperometry with ferricyanide as a thermotolerant external mediator. Clear differences in the intracellul...... in the intracellular electron flow and to probe redox enzyme properties of a strictly anaerobic thermophile in vivo.......Changes in the redox metabolism in the anaerobic, extremely thermophilic, hydrogen-forming bacterium Caldicellulosiruptor saccharolyticus were probed for the first time in vivo using mediated amperometry with ferricyanide as a thermotolerant external mediator. Clear differences in the intracellular...... the NADH-dependent lactate dehydrogenase, upon which more NADH was directed to membrane-associated enzymes for ferricyanide reduction, leading to a higher electrochemical signal. The method is noninvasive and the results presented here demonstrate that this method can be used to accurately detect changes...

  1. 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

  2. Cellulosic ethanol production via consolidated bioprocessing by a novel thermophilic anaerobic bacterium isolated from a Himalayan hot spring.

    Science.gov (United States)

    Singh, Nisha; Mathur, Anshu S; Tuli, Deepak K; Gupta, Ravi P; Barrow, Colin J; Puri, Munish

    2017-01-01

    Cellulose-degrading thermophilic anaerobic bacterium as a suitable host for consolidated bioprocessing (CBP) has been proposed as an economically suited platform for the production of second-generation biofuels. To recognize the overall objective of CBP, fermentation using co-culture of different cellulolytic and sugar-fermenting thermophilic anaerobic bacteria has been widely studied as an approach to achieving improved ethanol production. We assessed monoculture and co-culture fermentation of novel thermophilic anaerobic bacterium for ethanol production from real substrates under controlled conditions. In this study, Clostridium sp. DBT-IOC-C19, a cellulose-degrading thermophilic anaerobic bacterium, was isolated from the cellulolytic enrichment cultures obtained from a Himalayan hot spring. Strain DBT-IOC-C19 exhibited a broad substrate spectrum and presented single-step conversion of various cellulosic and hemicellulosic substrates to ethanol, acetate, and lactate with ethanol being the major fermentation product. Additionally, the effect of varying cellulose concentrations on the fermentation performance of the strain was studied, indicating a maximum cellulose utilization ability of 10 g L -1 cellulose. Avicel degradation kinetics of the strain DBT-IOC-C19 displayed 94.6% degradation at 5 g L -1 and 82.74% degradation at 10 g L -1 avicel concentration within 96 h of fermentation. In a comparative study with Clostridium thermocellum DSM 1313, the ethanol and total product concentrations were higher by the newly isolated strain on pretreated rice straw at an equivalent substrate loading. Three different co-culture combinations were used on various substrates that presented two-fold yield improvement than the monoculture during batch fermentation. This study demonstrated the direct fermentation ability of the novel thermophilic anaerobic bacteria on various cellulosic and hemicellulosic substrates into ethanol without the aid of any exogenous enzymes

  3. Previously unclassified bacteria dominate during thermophilic and mesophilic anaerobic pre-treatment of primary sludge.

    Science.gov (United States)

    Pervin, Hasina M; Batstone, Damien J; Bond, Philip L

    2013-06-01

    Thermophilic biological pre-treatment enables enhanced anaerobic digestion for treatment of wastewater sludges but, at present, there is limited understanding of the hydrolytic-acidogenic microbial composition and its contribution to this process. In this study, the process was assessed by comparing the microbiology of thermophilic (50-65 °C) and mesophilic (35 °C) pre-treatment reactors treating primary sludge. A full-cycle approach for the 16S rRNA genes was applied in order to monitor the diversity of bacteria and their abundance in a thermophilic pre-treatment reactor treating primary sludge. For the thermophilic pre-treatment (TP), over 90% of the sequences were previously undetected and these had less than 97% sequence similarity to cultured organisms. During the first 83 days, members of the Betaproteobacteria dominated the community sequences and a newly designed probe was used to monitor a previously unknown bacterium affiliated with the genus Brachymonas. Between days 85 and 183, three phylotypes that affiliated with the genera Comamonas, Clostridium and Lysobacter were persistently dominant in the TP community, as revealed by terminal-restriction fragment length polymorphism (T-RFLP). Hydrolytic and fermentative functions have been speculated for these bacteria. Mesophilic pre-treatment (MP) and TP communities were different but they were both relatively dynamic. Statistical correlation analysis and the function of closely allied reference organisms indicated that previously unclassified bacteria dominated the TP community and may have been functionally involved in the enhanced hydrolytic performance of thermophilic anaerobic pre-treatment. This study is the first to reveal the diversity and dynamics of bacteria during anaerobic digestion of primary sludge. Copyright © 2013 Elsevier GmbH. All rights reserved.

  4. Thermophilic anaerobic acetate-utilizing methanogens and their metabolism

    DEFF Research Database (Denmark)

    Mladenovska, Zuzana

    Six strains of thermophilic anaerobic acetate-utilizing methanogens were isolated from different full-scale thermophilic biogas plants in China and Denmark. The strain isolated from the Chinese biogas plant was designated KN-6P and the isolates from the Danish full-scale biogas plants were......, utilizing the substrates acetate, methanol and methylamines but not hydrogen/carbon dioxide. Strain Methanosarcina sp. SO-2P was able to grow mixotrophically on methanol and hydrogen/carbon dioxide with methane formation from hydrogen and carbon dioxide occurring after methanol depletion. All six...... designated HG-1P, LVG-4P R1-1P, SO-2P and V-1P. The isolates were characterized morphologically and physiologically, and their immunological and phylogenetic relatedness to already known isolated strains were established. All isolated strains were identified as organisms belonging to genus Methanosarcina...

  5. Improving anaerobic sewage sludge digestion by implementation of a hyper-thermophilic prehydrolysis step

    DEFF Research Database (Denmark)

    Lu, Jingquan; Gavala, Hariklia N.; Skiadas, Ioannis V.

    2008-01-01

    The present study focuses on a two-step process for treatment and stabilisation of primary sludge. The process consists of a hyperthermophilic hydrolysis step operated at 70 degrees C and a hydraulic retention time (HRT) of 2 clays followed by a thermophilic (55 degrees C) anaerobic digestion step......) with and Without pre-treatment respectively) and up to 115% increase of the methane production rate. Finally it was shown that the extra energy requirements for the operation of a pre-treatment step would be covered by the energy Produced from the extra methane production and in addition there would...

  6. Methanomethylovorans thermophila sp. nov., a thermophilic, methylotrophic methanogen form an anaerobic reactor fed with methanol

    NARCIS (Netherlands)

    Jiang, B.; Parshina, S.N.; Doesburg, van W.C.J.; Lomans, B.P.; Stams, A.J.M.

    2005-01-01

    A novel thermophilic, obligately methylotrophic, methanogenic archaeon, strain L2FAWT, was isolated from a thermophilic laboratory-scale upflow anaerobic sludge blanket reactor fed with methanol as the carbon and energy source. Cells of strain L2FAWT were non-motile, irregular cocci, 0·7¿1·5 µm in

  7. Moorella stamsii sp. nov., a new anaerobic thermophilic hydrogenogenic carboxydotroph isolated from digester sludge

    NARCIS (Netherlands)

    Alves, J.I.; Gelder, van A.H.; Alves, M.M.; Sousa, D.Z.; Plugge, C.M.

    2013-01-01

    A novel anaerobic, thermophilic, carbon monoxide-utilizing bacterium, strain E3-O, was isolated from anaerobic sludge of a municipal solid waste digester. Cells were straight rods, 0.6 to 1µm in diameter and 2 to 3 µm in length, growing as single cells or in pairs. Cells formed round terminal

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

    International Nuclear Information System (INIS)

    Moset, V.; Bertolini, E.; Cerisuelo, A.; Cambra, M.; Olmos, A.; Cambra-López, M.

    2014-01-01

    Sludge physicochemical composition, methane (CH 4 ) 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 CH 4 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 CH 4 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

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

    NARCIS (Netherlands)

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

    2002-01-01

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

  10. Startup and stability of thermophilic anaerobic digestion of OFMSW

    KAUST Repository

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2014-10-01

    Over 258 Mt of solid waste are generated annually in Europe, a large fraction of which is biowaste. Sewage sludge is another major waste fraction. In this study, biowaste and sewage sludge were co-digested in an anaerobic digestion reactor (30% and 70% of total wet weight, respectively). The purpose was to investigate the biogas production and methanogenic archaeal community composition in the anaerobic digestion reactor under meso- (35-37 °C) and thermophilic (55-57 °C) processes and an increasing organic loading rate (OLR, 1-10 kg VS m(-3) d(-1)), and also to find a feasible compromise between waste treatment capacity and biogas production without causing process instability. In summary, more biogas was produced with all OLRs by the thermophilic process. Both processes showed a limited diversity of the methanogenic archaeal community which was dominated by Methanobacteriales and Methanosarcinales (e.g. Methanosarcina) in both meso- and thermophilic processes. Methanothermobacter was detected as an additional dominant genus in the thermophilic process. In addition to operating temperatures, the OLRs, the acetate concentration, and the presence of key substrates like propionate also affected the methanogenic archaeal community composition. A bacterial cell count 6.25 times higher than archaeal cell count was observed throughout the thermophilic process, while the cell count ratio varied between 0.2 and 8.5 in the mesophilic process. This suggests that the thermophilic process is more stable, but also that the relative abundance between bacteria and archaea can vary without seriously affecting biogas production. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Hydrolytic activities of extracellular enzymes in thermophilic and mesophilic anaerobic sequencing-batch reactors treating organic fractions of municipal solid wastes.

    Science.gov (United States)

    Kim, Hyun-Woo; Nam, Joo-Youn; Kang, Seok-Tae; Kim, Dong-Hoon; Jung, Kyung-Won; Shin, Hang-Sik

    2012-04-01

    Extracellular enzymes offer active catalysis for hydrolysis of organic solid wastes in anaerobic digestion. To evidence the quantitative significance of hydrolytic enzyme activities for major waste components, track studies of thermophilic and mesophilic anaerobic sequencing-batch reactors (TASBR and MASBR) were conducted using a co-substrate of real organic wastes. During 1day batch cycle, TASBR showed higher amylase activity for carbohydrate (46%), protease activity for proteins (270%), and lipase activity for lipids (19%) than MASBR. In particular, the track study of protease identified that thermophilic anaerobes degraded protein polymers much more rapidly. Results revealed that differences in enzyme activities eventually affected acidogenic and methanogenic performances. It was demonstrated that the superior nature of enzymatic capability at thermophilic condition led to successive high-rate acidogenesis and 32% higher CH(4) recovery. Consequently, these results evidence that the coupling thermophilic digestion with sequencing-batch operation is a viable option to promote enzymatic hydrolysis of organic particulates. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Enrichment of anaerobic syngas-converting bacteria from thermophilic bioreactor sludge.

    Science.gov (United States)

    Alves, Joana I; Stams, Alfons J M; Plugge, Caroline M; Alves, M Madalena; Sousa, Diana Z

    2013-12-01

    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 partial pressures from 0.09 to 0.88 bar. Culture T-Syn, after 4 successive transfers with syngas, was also incubated with CO and subsequently transferred (9 transfers) with solely this substrate - cultures T-Syn-CO. Incubation with syngas and CO caused a rapid decrease in the microbial diversity of the anaerobic consortium. T-Syn and T-Syn-CO showed identical microbial composition and were dominated by Desulfotomaculum and Caloribacterium species. Incubation initiated with CO resulted in the enrichment of bacteria from the genera Thermincola and Thermoanaerobacter. Methane was detected in the first two to three transfers of T-Syn, but production ceased afterward. Acetate was the main product formed by T-Syn and T-Syn-CO. Enriched T-CO cultures showed a two-phase conversion, in which H2 was formed first and then converted to acetate. This research provides insight into how thermophilic anaerobic communities develop using syngas/CO as sole energy and carbon source can be steered for specific end products and subsequent microbial synthesis of chemicals. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

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

    Science.gov (United States)

    Jang, Hyun Min; Ha, Jeong Hyub; Park, Jong Moon; Kim, Mi-Sun; Sommer, Sven G

    2015-04-15

    A combined mesophilic anaerobic-thermophilic aerobic process was used to treat high-strength food wastewater in this study. During the experimental period, most of solid residue from the mesophilic anaerobic reactor (R1) was separated by centrifugation and introduced into the thermophilic aerobic reactor (R2) for further digestion. Then, thermophilic aerobically-digested sludge was reintroduced into R1 to enhance reactor performance. The combined process was operated with two different Runs: Run I with hydraulic retention time (HRT) = 40 d (corresponding OLR = 3.5 kg COD/m(3) d) and Run II with HRT = 20 d (corresponding OLR = 7 kg COD/m(3)). For a comparison, a single-stage mesophilic anaerobic reactor (R3) was operated concurrently with same OLRs and HRTs as the combined process. During the overall digestion, all reactors showed high stability without pH control. The combined process demonstrated significantly higher 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 of phylum Actinobacteria in both R1 and R2, and a predominance of phyla Synergistetes and Firmicutes in R3 during Run II. Furthermore, R1 and R2 shared genera (Prevotella, Aminobacterium, Geobacillus and Unclassified Actinobacteria), which suggests synergy between mesophilic anaerobic digestion and thermophilic aerobic digestion. For archaea, in R1 methanogenic archaea shifted from genus Methanosaeta to Methanosarcina, whereas genera Methanosaeta, Methanobacterium and Methanoculleus were predominant in R3. The results demonstrated dynamics of key microbial populations that were highly consistent with an enhanced reactor performance of the combined process. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2015-10-19

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

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

    Science.gov (United States)

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

    2018-01-15

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

  17. New thermophilic anaerobes that decompose crystalline cellulose

    Energy Technology Data Exchange (ETDEWEB)

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

    1985-01-01

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

  18. Occurrence and molecular characterization of cultivable mesophilic and thermophilic obligate anaerobic bacteria isolated from paper mills.

    Science.gov (United States)

    Suihko, Maija-Liisa; Partanen, Laila; Mattila-Sandholm, Tiina; Raaska, Laura

    2005-08-01

    The aim of this work was to characterize the cultivable obligate anaerobic bacterial population in paper mill environments. A total of 177 anaerobically grown bacterial isolates were screened for aerotolerance, from which 67 obligate anaerobes were characterized by automated ribotyping and 41 were further identified by partial 16S rDNA sequencing. The mesophilic isolates indicated 11 different taxa (species) within the genus Clostridium and the thermophilic isolates four taxa within the genus Thermoanaerobacterium and one within Thermoanaerobacter (both formerly Clostridium). The most widespread mesophilic bacterium was closely related to C. magnum and occurred in three of four mills. One mill was contaminated with a novel mesophilic bacterium most closely related to C. thiosulfatireducens. The most common thermophile was T. thermosaccharolyticum, occurring in all four mills. The genetic relationships of the mill isolates to described species indicated that most of them are potential members of new species. On the basis of identical ribotypes clay could be identified to be the contamination source of thermophilic bacteria. Automated ribotyping can be a useful tool for the identification of clostridia as soon as comprehensive identification libraries are available.

  19. Multiple approaches to characterize the microbial community in a thermophilic anaerobic digester running on swine manure: a case study.

    Science.gov (United States)

    Tuan, Nguyen Ngoc; Chang, Yi-Chia; Yu, Chang-Ping; Huang, Shir-Ly

    2014-01-01

    In this study, the first survey of microbial community in thermophilic anaerobic digester using swine manure as sole feedstock was performed by multiple approaches including denaturing gradient gel electrophoresis (DGGE), clone library and pyrosequencing techniques. The integrated analysis of 21 DGGE bands, 126 clones and 8506 pyrosequencing read sequences revealed that Clostridia from the phylum Firmicutes account for the most dominant Bacteria. In addition, our analysis also identified additional taxa that were missed by the previous researches, including members of the bacterial phyla Synergistetes, Planctomycetes, Armatimonadetes, Chloroflexi and Nitrospira which might also play a role in thermophilic anaerobic digester. Most archaeal 16S rRNA sequences could be assigned to the order Methanobacteriales instead of Methanomicrobiales comparing to previous studies. In addition, this study reported that the member of Methanothermobacter genus was firstly found in thermophilic anaerobic digester. Copyright © 2014 Elsevier GmbH. All rights reserved.

  20. Cellulolytic properties of an extremely thermophilic anaerobe

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-09-01

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

  1. 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...

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

    DEFF Research Database (Denmark)

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

    2009-01-01

    The aim of this study was to enrich, characterize and identify strict anaerobic extreme thermophilic hydrogen (H-2) producers from digested household solid wastes. A strict anaerobic extreme thermophilic H-2 producing bacterial culture was enriched from a lab-scale digester treating household...... wastes at 70 degrees C. The enriched mixed culture consisted of two rod-shaped bacterial members growing at an optimal temperature of 80 degrees C and an optimal pH 8.1. The culture was able to utilize glucose, galactose, mannose, xylose, arabinose, maltose, sucrose, pyruvate and glycerol as carbon...... sources. Growth on glucose produced acetate, H-2 and carbon dioxide. Maximal H-2 production rate on glucose was 1.1 mmol l(-1) h(-1) with a maximum H-2 yield of 1.9 mole H-2 per mole glucose. 16S ribosomal DNA clone library analyses showed that the culture members were phylogenetically affiliated...

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

    Science.gov (United States)

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

    2010-10-01

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

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  5. Combined thermophilic aerobic process and conventional anaerobic digestion: effect on sludge biodegradation and methane production.

    Science.gov (United States)

    Dumas, C; Perez, S; Paul, E; Lefebvre, X

    2010-04-01

    The efficiency of hyper-thermophilic (65 degrees Celsius) aerobic process coupled with a mesophilic (35 degrees Celsius) digester was evaluated for the activated sludge degradation and was compared to a conventional mesophilic digester. For two Sludge Retention Time (SRT), 21 and 42 days, the Chemical Oxygen Demand (COD) solubilisation and biodegradation processes, the methanisation yield and the aerobic oxidation were investigated during 180 days. The best results were obtained at SRT of 44 days; the COD removal yield was 30% higher with the Mesophilic Anaerobic Digestion/Thermophilic Aerobic Reactor (MAD-TAR) co-treatment. An increase of the sludge intrinsic biodegradability is also observed (20-40%), showing that the unbiodegradable COD in mesophilic conditions becomes bioavailable. However, the methanisation yield was quite similar for both processes at a same SRT. Finally, such a process enables to divide by two the volume of digester with an equivalent efficiency. Copyright 2009 Elsevier Ltd. All rights reserved.

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

    NARCIS (Netherlands)

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

    2002-01-01

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

  7. Improving biogas production from anaerobic co-digestion of Thickened Waste Activated Sludge (TWAS) and fat, oil and grease (FOG) using a dual-stage hyper-thermophilic/thermophilic semi-continuous reactor.

    Science.gov (United States)

    Alqaralleh, Rania Mona; Kennedy, Kevin; Delatolla, Robert

    2018-07-01

    This paper investigates the feasibility and advantages of using a dual-stage hyper-thermophilic/thermophilic semi-continuous reactor system for the co-digestion of Thickened Waste Activated Sludge (TWAS) and Fat, Oil and Grease (FOG) to produce biogas in high quantity and quality. The performance of the dual-stage hyper-thermophilic (70°C)/thermophilic (55°C) anaerobic co-digestion system is evaluated and compared to the performance of a single-stage thermophilic (55°C) reactor that was used to co-digest the same FOG-TWAS mixtures. Both co-digestion reactors were compared to a control reactor (the control reactor was a single-stage thermophilic reactor that only digested TWAS). The effect of FOG% in the co-digestion mixture (based on total volatile solids) and the reactor hydraulic retention time (HRT) on the biogas/methane production and the reactors' performance were thoroughly investigated. The FOG% that led to the maximum methane yield with a stable reactor performance was determined for both reactors. The maximum FOG% obtained for the single-stage thermophilic reactor at 15 days HRT was found to be 65%. This 65% FOG resulted in 88.3% higher methane yield compared to the control reactor. However, the dual-stage hyper-thermophilic/thermophilic co-digestion reactor proved to be more efficient than the single-stage thermophilic co-digestion reactor, as it was able to digest up to 70% FOG with a stable reactor performance. The 70% FOG in the co-digestion mixture resulted in 148.2% higher methane yield compared to the control at 15 days HRT. 70% FOG (based on total volatile solids) is so far the highest FOG% that has been proved to be useful and safe for semi-continuous reactor application in the open literature. Finally, the dual-stage hyper-thermophilic/thermophilic co-digestion reactor also proved to be efficient and stable in co-digesting 40% FOG mixtures at lower HRTs (i.e., 9 and 12 days) and still produce high methane yields and Class A effluents

  8. 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.

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

    DEFF Research Database (Denmark)

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

    2007-01-01

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

  10. High performance biological methanation in a thermophilic anaerobic trickle bed reactor.

    Science.gov (United States)

    Strübing, Dietmar; Huber, Bettina; Lebuhn, Michael; Drewes, Jörg E; Koch, Konrad

    2017-12-01

    In order to enhance energy efficiency of biological methanation of CO 2 and H 2 , this study investigated the performance of a thermophilic (55°C) anaerobic trickle bed reactor (ATBR) (58.1L) at ambient pressure. With a methane production rate of up to 15.4m 3 CH4 /(m 3 trickle bed ·d) at methane concentrations above 98%, the ATBR can easily compete with the performance of other mixed culture methanation reactors. Control of pH and nutrient supply turned out to be crucial for stable operation and was affected significantly by dilution due to metabolic water production, especially during demand-orientated operation. Considering practical applications, inoculation with digested sludge, containing a diverse biocenosis, showed high adaptive capacity due to intrinsic biological diversity. However, no macroscopic biofilm formation was observed at thermophilic conditions even after 313days of operation. The applied approach illustrates the high potential of thermophilic ATBRs as a very efficient energy conversion and storage technology. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Dry co-digestion of sewage sludge and rice straw under mesophilic and thermophilic anaerobic conditions.

    Science.gov (United States)

    Chu, Xiangqian; Wu, Guangxue; Wang, Jiaquan; Hu, Zhen-Hu

    2015-12-01

    Dry anaerobic digestion of sewage sludge can recover biogas as energy; however, its low C/N ratio limits it as a single substrate in the anaerobic digestion. Rice straw is an abundant agricultural residue in China, which is rich in carbon and can be used as carbon source. In the present study, the performance of dry co-digestion of sewage sludge and rice straw was investigated under mesophilic (35 °C) and thermophilic (55 °C) conditions. The operational factors impacting dry co-digestion of sewage sludge and rice straw such as C/N ratio, moisture content, and initial pH were explored under mesophilic conditions. The results show that low C/N ratios resulted in a higher biogas production rate, but a lower specific biogas yield; low moisture content of 65 % resulted in the instability of the digestion system and a low specific biogas yield. Initial pH ranging 7.0-9.0 did not affect the performance of the anaerobic digestion. The C/N ratio of 26-29:1, moisture content of 70-80 %, and pH 7.0-9.0 resulted in good performance in the dry mesophilic co-digestion of sewage sludge and rice straw. As compared with mesophilic digestion, thermophilic co-digestion of sewage sludge and rice straw significantly enhanced the degradation efficiency of the substrates and the specific biogas yield (p sewage sludge under mesophilic and thermophilic conditions.

  12. 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

    did not affect egg survival during the first 48h and it took up to 10days before total elimination was reached. In general, anaerobic digestion in biogas plants seems an efficient way (thermophilic more efficient than mesophilic) to treat organic farm wastes in a way that suppresses animal parasites......, Ascaris suum, was assessed under conditions similar to biogas plants managed at meso- (37°C) and thermophilic (55°C) conditions. Cattle manure was used as digestion substrate and experimental units were sampled destructively over time. Regarding weed seeds, the effect of thermophilic conditions (55°C...

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

    International Nuclear Information System (INIS)

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

    1995-01-01

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

  14. Characterisation of community structure of bacteria in parallel mesophilic and thermophilic pilot scale anaerobe sludge digesters.

    Science.gov (United States)

    Tauber, T; Berta, Brigitta; Székely, Anna J; Gyarmati, I; Kékesi, Katalin; Márialigeti, K; Tóth, Erika M

    2007-03-01

    The aim of the present work was to compare the microbial communities of a mesophilic and a thermophilic pilot scale anaerobe sludge digester. For studying the communities cultivation independent chemotaxonomical methods (RQ and PLFA analyses) and T-RFLP were applied. Microbial communities of the mesophilic and thermophilic pilot digesters showed considerable differences, both concerning the species present, and their abundance. A Methanosarcina sp. dominated the thermophilic, while a Methanosaeta sp. the mesophilic digester among Archaea. Species diversity of Bacteria was reduced in the thermophilic digester. Based on the quinone patterns in both digesters the dominance of sulphate reducing respiratory bacteria could be detected. The PLFA profiles of the digester communities were similar though in minor components characteristic differences were shown. Level of branched chain fatty acids is slightly lower in the thermophilic digester that reports less Gram positive bacteria. The relative ratio of fatty acids characteristic to Enterobacteriaceae, Bacteroidetes and Clostridia shows differences between the two digesters: their importance generally decreased under thermophilic conditions. The sulphate reducer marker (15:1 and 17:1) fatty acids are present in low quantity in both digesters.

  15. 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

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

    DEFF Research Database (Denmark)

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

    1995-01-01

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

  17. 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

    solubilization was investigated. The two process parameters had little effect on the solubilization of hemicellulose. However alkaline conditions affected the furfural formation whereas oxygen had no effect. After pretreatment, the filtrate was used as a fermentation medium for thermophilic anaerobic bacterin...

  18. Biological hydrogen production by moderately thermophilic anaerobic bacteria

    International Nuclear Information System (INIS)

    HP Goorissen; AJM Stams

    2006-01-01

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

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

    Science.gov (United States)

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

    2018-05-01

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

  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. 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.

  2. 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

  3. Feasibility of thermophilic anaerobic processes for treating waste activated sludge under low HRT and intermittent mixing.

    Science.gov (United States)

    Leite, Wanderli; Magnus, Bruna Scandolara; Guimarães, Lorena Bittencourt; Gottardo, Marco; Belli Filho, Paulo

    2017-10-01

    Thermophilic anaerobic digestion (AD) arises as an optimized solution for the waste activated sludge (WAS) management. However, there are few feasibility studies using low solids content typically found in the WAS, and that consider uncommon operational conditions such as intermittent mixing and low hydraulic retention time (HRT). In this investigation, a single-stage pilot reactor was used to treat WAS at low HRT (13, 9, 6 and 5 days) and intermittent mixing (withholding mixing 2 h prior feeding). Thermophilic anaerobic digestion (55 °C) was initiated from a mesophilic digester (35 °C) by the one-step startup strategy. Although instabilities on partial alkalinity (1245-3000 mgCaCO 3 /L), volatile fatty acids (1774-6421 mg/L acetic acid) and biogas production (0.21-0.09 m 3 /m 3 reactor .d) were observed, methanogenesis started to recover in 18 days. The thermophilic treatment of WAS at 13 and 9 days HRT efficiently converted VS into biogas (22 and 21%, respectively) and achieved high biogas yield (0.24 and 0.22 m 3 /kgVS fed , respectively). Intermittent mixing improved the retention of methanogens inside the reactor and reduced the washout effect even at low HRT (5% TS). Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Silver Sulfidation in Thermophilic Anaerobic Digesters and Effects on Antibiotic Resistance Genes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bojeong; Miller, Jennifer H.; Monsegue, Niven; Levard, Clément; Hong, Yanjuan; Hull, Matthew S.; Murayama, Mitsuhiro; Brown, Gordon E.; Vikesland, Peter J.; Knocke, William R.; Pruden, Amy; Hochella, Michael F.

    2015-12-15

    Physical and chemical transformations and biological responses of silver nanoparticles (AgNPs) in wastewater treatment systems are of particular interest because of the extensive existing and continually growing uses of AgNPs in consumer products. In this study, we investigated the transformation of AgNPs and AgNO3 during thermophilic anaerobic digestion and effects on selection or transfer of antibiotic resistance genes (ARGs). Ag2S-NPs, sulfidation products of both AgNPs and AgNO3, were recovered from raw and digested sludges and were analyzed by analytical transmission electron microscopy (TEM) and X-ray absorption spectroscopy (XAS). TEM and XAS revealed rapid (≤20 min) Ag sulfidation for both Ag treatments. Once transformed, Ag2S-NPs (as individual NPs or an NP aggregate) persisted for the duration of the batch digestion. The digestion process produced Ag2S-NPs that were strongly associated with sludge organics and/or other inorganic precipitates. Ag treatments (up to 1,000 mg Ag/kg) did not have an impact on the performance of thermophilic anaerobic digesters or ARG response, as indicated by quantitative polymerase chain reaction measurements of sul1, tet(W), and tet(O) and also intI1, an indicator of horizontal gene transfer of ARGs. Thus, rapid Ag sulfidation and stabilization with organics effectively sequester Ag and prevent biological interactions with the digester microbial community that could induce horizontal gene transfer or adversely impact digester performance through antimicrobial activity. This finding suggests that sulfide-rich anaerobic environments, such as digesters, likely have a high buffer capacity to mitigate the biological effects of AgNPs.

  5. 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

  6. 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)

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

    International Nuclear Information System (INIS)

    Park, Y.J.; Hong, F.; Japan Science and Technology Agency, Tokyo; Tsuno, H.; Hidaka, T.; Cheon, J.H.; Japan Science and Technology Agency, Tokyo

    2004-01-01

    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

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

    Science.gov (United States)

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

    2011-12-01

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

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

    Science.gov (United States)

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

    2013-02-01

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

  10. 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.

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

    KAUST Repository

    Atallah, Nabil M.; El-Fadel, Mutasem E.; Ghanimeh, Sophia A.; Saikaly, Pascal; Abou Najm, Majdi R.

    2014-01-01

    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.

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

    International Nuclear Information System (INIS)

    Yang, Yingnan; Tsukahara, Kenichiro; Sawayama, Shigeki

    2007-01-01

    A newly developed anaerobic rotating disk reactor (ARDR) packed with polyurethane was used in continuous mode for organic waste removal under thermophilic (55 o C) 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

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

    Science.gov (United States)

    Atallah, Nabil M; El-Fadel, Mutasem; Ghanimeh, Sophia; Saikaly, Pascal; Abou-Najm, Majdi

    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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Optimization of micronutrient supplement for enhancing biogas production from food waste in two-phase thermophilic anaerobic digestion.

    Science.gov (United States)

    Menon, Ajay; Wang, Jing-Yuan; Giannis, Apostolos

    2017-01-01

    The aim of this study was to enhance the biogas productivity of two-phase thermophilic anaerobic digestion (AD) using food waste (FW) as the primary substrate. The influence of adding four trace metals (Ca, Mg, Co, and Ni) as micronutrient supplement in the methanogenic phase of the thermophilic system was investigated. Initially, Response Surface Methodology (RSM) was applied to determine the optimal concentration of micronutrients in batch experiments. The results showed that optimal concentrations of 303, 777, 7 and 3mg/L of Ca, Mg, Co and Ni, respectively, increased the biogas productivity as much as 50% and significantly reduced the processing time. The formulated supplement was tested in continuous two-phase thermophilic AD system with regard to process stability and productivity. It was found that a destabilized thermophilic AD process encountering high VFA accumulation recovered in less than two weeks, while the biogas production was improved by 40% yielding 0.46L CH 4 /gVS added /day. There was also a major increase in soluble COD utilization upon the addition of micronutrient supplement. The results of this study indicate that a micronutrient supplement containing Ca, Mg, Co and Ni could probably remedy any type of thermophilic AD process. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2015-05-01

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

  16. 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

  17. 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

    The degradation kinetics of normal and branched chain butyrate and valerate are important in protein-fed anaerobic systems, as a number of amino acids degrade to these organic acids. Including activated and primary wastewater sludge digesters, the majority of full-scale systems digest feeds...... is also addressed, extending previous pure-culture and batch studies. A previously published mathematical model was modified to allow competitive uptake of i-valerate, and used to model a thermophilic manure digester operated over 180 days. The digester was periodically pulsed with straight and branched...

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

    International Nuclear Information System (INIS)

    Zamalloa, Carlos; Boon, Nico; Verstraete, Willy

    2012-01-01

    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 (B 0 ) 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 CH 4 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.

  19. 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...

  20. Performance of thermophilic anaerobic digesters using inoculum mixes with enhanced methanogenic diversity

    KAUST Repository

    Ghanimeh, Sophia

    2017-05-30

    BACKGROUND Reportedly, various mixes of seeds were quasi-randomly selected to startup anaerobic digesters. In contrast, this study examines the impact of inoculating thermophilic anaerobic digesters with a designed mix of non-acclimated seeds based on their methanogen composition, using Quantitative Polymerase Chain Reaction (QPCR) of 16S rRNA gene, to achieve high abundance and diversity of methanogens. RESULTS Based on QPCR results, two seed mixes were selected to inoculate two anaerobic digesters: digester (A) was inoculated with a control seed consisting of digestate, manure, and activated sludge; and digester (B) was inoculated with a further methanogen-enriched seed consisting of the control seed with added compost and leachate. Both seed combinations yielded a balanced microflora that is able to achieve a successful startup. However, upon reaching steady state, digester B exhibited lower propionate levels, resulting in lower VFA concentration and increased buffering capacity, indicating greater stability. Acetotrophs and hydrogenotrophs were dominated by Methanosarcinaceae and Methanobacteriales, respectively, in both digesters, exhibiting an average ratio of 66-to-34% in A and 76-to-24% in B during steady state. CONCLUSION The inoculation strategy in digester B resulted in improved stability, lower propionate concentration and 10% higher relative abundance of acetotrophs.

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

    Science.gov (United States)

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

    2010-06-01

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

  2. The role of zero valent iron on the fate of tetracycline resistance genes and class 1 integrons during thermophilic anaerobic co-digestion of waste sludge and kitchen waste.

    Science.gov (United States)

    Gao, Pin; Gu, Chaochao; Wei, Xin; Li, Xiang; Chen, Hong; Jia, Hanzhong; Liu, Zhenhong; Xue, Gang; Ma, Chunyan

    2017-03-15

    Activated sludge has been identified as a potential significant source of antibiotic resistance genes (ARGs) to the environment. Anaerobic digestion is extensively used for sludge stabilization and resource recovery, and represents a crucial process for controlling the dissemination of ARGs prior to land application of digested sludge. The objective of this study is to investigate the effect of zero valent iron (Fe 0 ) on the attenuation of seven representative tetracycline resistance genes (tet, tet(A), tet(C), tet(G), tet(M), tet(O), tet(W), and tet(X)), and the integrase gene intI1 during thermophilic anaerobic co-digestion of waste sludge and kitchen waste. Significant decrease (P  0.05) were found for all gene targets between digesters with Fe 0 dosages of 5 and 60 g/L. A first-order kinetic model favorably described the trends in concentrations of tet and intI1 gene targets during thermophilic anaerobic digestion with or without Fe 0 . Notably, tet genes encoding different resistance mechanisms behaved distinctly in anaerobic digesters, although addition of Fe 0 could enhance their reduction. The overall results of this research suggest that thermophilic anaerobic digestion with Fe 0 can be a potential alternative technology for the attenuation of tet and intI1 genes in waste sludge. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. 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...

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

    Science.gov (United States)

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

    2015-06-01

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

  5. 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......) and Thermoanaerobacterium thermosaccharolyticum with a relative abundance of 36%, 27%, and 10% of total microorganisms, respectively. This study shows that hydrogen production could be efficiently facilitated by using anaerobic granules as a carrier, where microbes from mixed culture enriched in the DM batch cultivation....... The enriched hydrogen producing mixed culture achieved from the 16.7 g-sugars/L DM batch cultivation was immobilized on heat treated anaerobic sludge granules in an up-flow anaerobic sludge blanket (UASB) reactor. The UASB reactor, operated at a hydraulic retention time (HRT) of 24 h fed with 16.7 g...

  6. Action of amylolytic and pullulytic enzymes from various anaerobic thermophiles on linear and branched glucose polymers

    Energy Technology Data Exchange (ETDEWEB)

    Koch, R [Goettingen Univ. (Germany, F.R.). Inst. fuer Mikrobiologie; Antranikian, G [Technische Univ. Hamburg-Harburg, Hamburg (Germany, F.R.). Arbeitsbereich Biotechnologie 1

    1990-10-01

    A detailed study has been conducted on the action of starch hydrolyzing enzymes from thermophilic anaerobic bacteria belonging to the genera Clostridium, Thermoanaerobacter and Thermobacteroides. The appearance of multiple bands on polyacrylamide gels with amylolytic as well as pullulytic activities was shown to be a general feature of bacteria investigated. Analysis of the hydrolysis products of each protein band clearly demonstrated the capability of these organisms to hydrolyze {alpha}-1,4-glycosidic bonds in linear oligosaccharides and {alpha}-1,6-glycosidic linkages in pullulan. Furthermore, the enzyme system of thermophilic bacteria investigated was also capable of attacking in the {alpha}-1,6-linkages in branched oligosaccharides. Due to the action of these thermoactive enzymes with multiple specificity an almost complete hydrolysis of raw starch and maltodextrin could be achieved under the same conditions and in one step. (orig.).

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

    Science.gov (United States)

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

    2011-01-01

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

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

    Science.gov (United States)

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

    2006-10-01

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

  9. Upflow anaerobic sludge blanket-hollow centered packed bed (UASB-HCPB) reactor for thermophilic palm oil mill effluent (POME) treatment

    International Nuclear Information System (INIS)

    Poh, P.E.; Chong, M.F.

    2014-01-01

    Upflow anaerobic sludge blanket-hollow centered packed bed (UASB-HCPB) reactor was developed with the aim to minimize operational problems in the anaerobic treatment of Palm Oil Mill Effluent (POME) under thermophilic conditions. The performance of UASB-HCPB reactor on POME treatment was investigated at 55 °C. Subsequent to start-up, the performance of the UASB-HCPB reactor was evaluated in terms of i) effect of hydraulic retention time (HRT); ii) effect of organic loading rate (OLR); and iii) effect of mixed liquor volatile suspended solid (MLVSS) concentration on thermophilic POME treatment. Start-up up of the UASB-HCPB reactor was completed in 36 days, removing 88% COD and 90% BOD respectively at an OLR of 28.12 g L −1  d −1 , producing biogas with 52% of methane. Results from the performance study of the UASB-HCPB reactor on thermophilic POME treatment indicated that HRT of 2 days, OLR of 27.65 g L −1  d −1 and MLVSS concentration of 14.7 g L −1 was required to remove 90% of COD and BOD, 80% of suspended solid and at the same time produce 60% of methane. - Highlights: • UASB-HCPB was proposed for POME treatment under thermophilic conditions. • Start-up up of the UASB-HCPB reactor was completed in 36 days. • 88% COD and 90% BOD were removed at an OLR of 28.12 g COD/L.day during start-up. • HRT of 2 days and OLR of 27.65 g COD/L.day was required to produce 60% methane. • Methanosarcina sp. forms the majority of microbial population in the UASB section

  10. Evolution of microorganisms in thermophilic-dry anaerobic digestion.

    Science.gov (United States)

    Montero, B; Garcia-Morales, J L; Sales, D; Solera, R

    2008-05-01

    Microbial population dynamics were studied during the start-up and stabilization periods in thermophilic-dry anaerobic digestion at lab-scale. The experimental protocol was defined to quantify Eubacteria and Archaea using Fluorescent in situ hybridization (FISH) in a continuously stirred tank reactor (CSTR), without recycling solids. The reactor was subjected to a programme of steady-state operation over a range of the retention times from 40 to 25 days, with an organic loading rate between 4.42 and 7.50 kg volatile solid/m3/day. Changes in microbial concentrations were linked to traditional performance parameters such as biogas production and VS removal. The relations of Eubacteria:Archaea and H2-utilising methanogens:acetate-utilising methanogens were 88:12 and 11:1, respectively, during start-up stage. Hydrogenotrophic methanogens, although important in the initial phase of the reactor start-up, were displaced by acetoclastic methanogens at steady-state, thus their relation were 7:32, respectively. The methane yield coefficient, the methane content in the biogas and VS removal were stabilized around 0.30 LCH4/gCOD, 50% and 80%, respectively. Methanogenic population correlated well with performance measurements.

  11. Thermal pre-treatment of primary and secondary sludge at 70 °C prior to anaerobic digestion

    DEFF Research Database (Denmark)

    Skiadas, Ioannis; Gavala, Hariklia N.; Lu, J.

    2005-01-01

    In general, mesophilic anaerobic digestion of sewage sludge is more widely used compared tothermophilic digestion, mainly because of the lower energy requirements and higher stability of the process. However, the thermophilic anaerobic digestion process is usually characterised by accelerated...... studyinvestigates the effect of the pre-treatment at 70 °C on thermophilic (55 °C) anaerobic digestion of primaryand secondary sludge in continuously operated digesters. Thermal pre-treatment of primary and secondarysludge at 70 °C enhanced the removal of organic matter and the methane production during...... the subsequentanaerobic digestion step at 55 °C. It also greatly contributed to the destruction of pathogens present inprimary sludge. Finally it results in enhanced microbial activities of the subsequent anaerobic stepsuggesting that the same efficiencies in organic matter removal and methane recovery could be obtained...

  12. 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.

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

    KAUST Repository

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

    2013-01-01

    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.

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

    Science.gov (United States)

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

    2016-07-01

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

  15. 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

  16. 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.

  17. Survival of weed seeds and animal parasites as affected by anaerobic digestion at meso- and thermophilic conditions.

    Science.gov (United States)

    Johansen, Anders; Nielsen, Henrik B; Hansen, Christian M; Andreasen, Christian; Carlsgart, Josefine; Hauggard-Nielsen, Henrik; Roepstorff, Allan

    2013-04-01

    Anaerobic digestion of residual materials from animals and crops offers an opportunity to simultaneously produce bioenergy and plant fertilizers at single farms and in farm communities where input substrate materials and resulting digested residues are shared among member farms. A surplus benefit from this practice may be the suppressing of propagules from harmful biological pests like weeds and animal pathogens (e.g. parasites). In the present work, batch experiments were performed, where survival of seeds of seven species of weeds and non-embryonated eggs of the large roundworm of pigs, Ascaris suum, was assessed under conditions similar to biogas plants managed at meso- (37°C) and thermophilic (55°C) conditions. Cattle manure was used as digestion substrate and experimental units were sampled destructively over time. Regarding weed seeds, the effect of thermophilic conditions (55°C) 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 maintained low levels (~1%) of germination ability after 1 week. Chenopodium album was the only weed species which survived 1 week at substantial levels (7%) although after 11 d germination ability was totally lost. Similarly, at 55°C, no Ascaris eggs survived more than 3h of incubation. Incubation at 37°C did not affect egg survival during the first 48 h and it took up to 10 days before total elimination was reached. In general, anaerobic digestion in biogas plants seems an efficient way (thermophilic more efficient than mesophilic) to treat organic farm wastes in a way that suppresses animal parasites and weeds so that the digestates can be applied without risking spread of these pests. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. 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 re...... with highest similarity to DNA repair protein from Campylobacter jejuni (25% aa). Orf34 showed similarity to sigma factors with highest similarity (28% aa) to the sporulation specific Sigma factor, Sigma 28(K) from Bacillus thuringiensis....

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

    OpenAIRE

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

    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...

  20. Anaerobic digestion of nitrogen rich poultry manure: Impact of thermophilic biogas process on metal release and microbial resistances.

    Science.gov (United States)

    Anjum, Reshma; Grohmann, Elisabeth; Krakat, Niclas

    2017-02-01

    Poultry manure is a nitrogen rich fertilizer, which is usually recycled and spread on agricultural fields. Due to its high nutrient content, chicken manure is considered to be one of the most valuable animal wastes as organic fertilizer. However, when chicken litter is applied in its native form, concerns are raised as such fertilizers also include high amounts of antibiotic resistant pathogenic Bacteria and heavy metals. We studied the impact of an anaerobic thermophilic digestion process on poultry manure. Particularly, microbial antibiotic resistance profiles, mobile genetic elements promoting the resistance dissemination in the environment as well as the presence of heavy metals were focused in this study. The initiated heat treatment fostered a community shift from pathogenic to less pathogenic bacterial groups. Phenotypic and molecular studies demonstrated a clear reduction of multiple resistant pathogens and self-transmissible plasmids in the heat treated manure. That treatment also induced a higher release of metals and macroelements. Especially, Zn and Cu exceeded toxic thresholds. Although the concentrations of a few metals reached toxic levels after the anaerobic thermophilic treatment, the quality of poultry manure as organic fertilizer may raise significantly due to the elimination of antibiotic resistance genes (ARG) and self-transmissible plasmids. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. 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

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

    Science.gov (United States)

    Gebreeyessus, Getachew D.; Jenicek, Pavel

    2016-01-01

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

  3. Anaerobic digestion of spent mushroom substrate under thermophilic conditions: performance and microbial community analysis.

    Science.gov (United States)

    Xiao, Zheng; Lin, Manhong; Fan, Jinlin; Chen, Yixuan; Zhao, Chao; Liu, Bin

    2018-01-01

    Spent mushroom substrate (SMS) is the residue of edible mushroom production occurring in huge amounts. The SMS residue can be digested for biogas production in the mesophilic anaerobic digestion. In the present study, performance of batch thermophilic anaerobic digestion (TAD) of SMS was investigated as well as the interconnected microbial population structure changes. The analyzed batch TAD process lasted for 12 days with the cumulative methane yields of 177.69 mL/g volatile solid (VS). Hydrolytic activities of soluble sugar, crude protein, and crude fat in SMS were conducted mainly in the initial phase, accompanied by the excessive accumulation of volatile fatty acids and low methane yield. Biogas production increased dramatically from days 4 to 6. The degradation rates of cellulose and hemicellulose were 47.53 and 55.08%, respectively. The high-throughput sequencing of 16S rRNA gene amplicons revealed that Proteobacteria (56.7%-62.8%) was the dominant phylum in different fermentative stages, which was highly specific compared with other anaerobic processes of lignocellulosic materials reported in the literature. Crenarchaeota was abundant in the archaea. The most dominant genera of archaea were retrieved as Methanothermobacter and Methanobacterium, but the latter decreased sharply with time. This study shows that TAD is a feasible method to handle the waste SMS.

  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. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2017-10-01

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

  6. 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.

  7. Fate of antibiotic resistance genes in mesophilic and thermophilic anaerobic digestion of chemically enhanced primary treatment (CEPT) sludge.

    Science.gov (United States)

    Jang, Hyun Min; Shin, Jingyeong; Choi, Sangki; Shin, Seung Gu; Park, Ki Young; Cho, Jinwoo; Kim, Young Mo

    2017-11-01

    Anaerobic digestion (AD) of chemically enhanced primary treatment (CEPT) sludge and non-CEPT (conventional sedimentation) sludge were comparatively operated under mesophilic and thermophilic conditions. The highest methane yield (692.46±0.46mL CH 4 /g VS removed in CEPT sludge) was observed in mesophilic AD of CEPT sludge. Meanwhile, thermophilic conditions were more favorable for the removal of total antibiotic resistance genes (ARGs). In this study, no measurable difference in the fates and removal of ARGs and class 1 integrin-integrase gene (intI1) was observed between treated non-CEPT and CEPT sludge. However, redundancy analysis indicated that shifts in bacterial community were primarily accountable for the variations in ARGs and intI1. Network analysis further revealed potential host bacteria for ARGs and intI1. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Effect of alkaline pretreatment on mesophilic and thermophilic anaerobic digestion of a submerged macrophyte: Inhibition and recovery against dissolved lignin during semi-continuous operation.

    Science.gov (United States)

    Koyama, Mitsuhiko; Watanabe, Keiko; Kurosawa, Norio; Ishikawa, Kanako; Ban, Syuhei; Toda, Tatsuki

    2017-08-01

    The long-term effect of alkaline pretreatment on semi-continuous anaerobic digestion (AD) of the lignin-rich submerged macrophyte Potamogeton maackianus was investigated using mesophilic and thermophilic conditions. In pretreated reactors, dissolved lignin accumulated to high levels. CH 4 production under the pretreated condition was higher than that of the untreated condition, but decreased from Days 22 (mesophilic) and 42 (thermophilic). However, CH 4 production subsequently recovered, although dissolved lignin accumulated. Further, the change in the microbial community was observed between conditions. These results suggest that dissolved lignin temporarily inhibited AD, although acclimatization to dissolved lignin occurred during long-term operation. During the steady state period, mesophilic conditions achieved a 42% increase in the CH 4 yield using pretreatment, while thermophilic conditions yielded an 8% increment. Because volatile fatty acids accumulated even after acclimatization during the thermophilic pretreated condition and was discharged with the effluent, improvement of the methanogenic step would enable enhanced CH 4 recovery. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. A new approach for concurrently improving performance of South Korean food waste valorization and renewable energy recovery via dry anaerobic digestion under mesophilic and thermophilic conditions.

    Science.gov (United States)

    Nguyen, Dinh Duc; Yeop, Jeong Seong; Choi, Jaehoon; Kim, Sungsu; Chang, Soon Woong; Jeon, Byong-Hun; Guo, Wenshan; Ngo, Huu Hao

    2017-08-01

    Dry semicontinuous anaerobic digestion (AD) of South Korean food waste (FW) under four solid loading rates (SLRs) (2.30-9.21kg total solids (TS)/m 3 day) and at a fixed TS content was compared between two digesters, one each under mesophilic and thermophilic conditions. Biogas production and organic matter reduction in both digesters followed similar trends, increasing with rising SLR. Inhibitor (intermediate products of the anaerobic fermentation process) effects on the digesters' performance were not observed under the studied conditions. In all cases tested, the digesters' best performance was achieved at the SLR of 9.21kg TS/m 3 day, with 74.02% and 80.98% reduction of volatile solids (VS), 0.87 and 0.90m 3 biogas/kg VS removed , and 0.65 (65% CH 4 ) and 0.73 (60.02% CH 4 ) m 3 biogas/kg VS fed , under mesophilic and thermophilic conditions, respectively. Thermophilic dry AD is recommended for FW treatment in South Korea because it is more efficient and has higher energy recovery potential when compared to mesophilic dry AD. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. An innovative intermittent-vacuum assisted thermophilic anaerobic digestion process for effective animal manure utilization and treatment.

    Science.gov (United States)

    Zhang, Renchuan; Anderson, Erik; Addy, Min; Deng, Xiangyuan; Kabir, Fayal; Lu, Qian; Ma, Yiwei; Cheng, Yanling; Liu, Yuhuan; Chen, Paul; Ruan, Roger

    2017-11-01

    Intermittent-vacuum stripping (IVS) was developed as a pretreatment for thermophilic anaerobic digestion (TAD) to improve methanogenesis and hydrolysis activity through preventing free ammonia and hydrogen sulfide (H 2 S) inhibition from liquid swine manure (LSM). Over 98% of ammonia and 38% organic nitrogen were removed in 60min from 55°C to 85°C with vacuum pressure (from 100.63±3.79mmHg to 360.91±7.39mmHg) at initial pH 10.0 by IVS. Thermophilic methanogenesis and hydrolysis activity of pretreated LSM increased 52.25% (from 11.56±1.75% to 17.60±0.49%) in 25days and 40% (from 10days to 6days) in bio-methane potential assay. Over 80% H 2 S and total nitrogen were removed by IVS assistance, while around 70% nitrogen was recycled as ammonium sulfate. Therefore, IVS-TAD combination could be an effective strategy to improve TAD efficiency, whose elution is more easily utilized in algae cultivation and/or hydroponic system. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2009-09-01

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

  12. Influence of initial pH on thermophilic anaerobic co-digestion of swine manure and maize stalk.

    Science.gov (United States)

    Zhang, Tong; Mao, Chunlan; Zhai, Ningning; Wang, Xiaojiao; Yang, Gaihe

    2015-01-01

    The contradictions between the increasing energy demand and decreasing fossil fuels are making the use of renewable energy the key to the sustainable development of energy in the future. Biogas, a renewable clean energy, can be obtained by the anaerobic fermentation of manure waste and agricultural straw. This study examined the initial pH value had obvious effect on methane production and the process in the thermophilic anaerobic co-digestion. Five different initial pH levels with three different manure ratios were tested. All digesters in different initial pH showed a diverse methane production after 35 days. The VFA/alkalinity ratio of the optimum reaction condition for methanogens activity was in the range of 0.1-0.3 and the optimal condition that at the 70% dung ratio and initial pH 6.81, was expected to achieve maximum total biogas production (146.32 mL/g VS). Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. 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 unique method was developed and applied for monitoring methanogenesis pathways based on isotope labeled substrates combined with online membrane inlet quadrupole mass spectrometry (MIMS). In our study, a fermentation sample from a full-scale biogas plant fed with pig and cattle manure, maize...... silage, and deep litter was incubated with 100 mM of [2-13C] sodium acetate under thermophilic anaerobic conditions. MIMS was used to measure the isotopic distribution of dissolved CO2 and CH4 during the degradation of acetate, while excluding interference from water by applying a cold trap. After 6 days...... 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...

  14. Quantitative Metaproteomics Highlight the Metabolic Contributions of Uncultured Phylotypes in a Thermophilic Anaerobic Digester.

    Science.gov (United States)

    Hagen, Live H; Frank, Jeremy A; Zamanzadeh, Mirzaman; Eijsink, Vincent G H; Pope, Phillip B; Horn, Svein J; Arntzen, Magnus Ø

    2017-01-15

    In this study, we used multiple meta-omic approaches to characterize the microbial community and the active metabolic pathways of a stable industrial biogas reactor with food waste as the dominant feedstock, operating at thermophilic temperatures (60°C) and elevated levels of free ammonia (367 mg/liter NH 3 -N). The microbial community was strongly dominated (76% of all 16S rRNA amplicon sequences) by populations closely related to the proteolytic bacterium Coprothermobacter proteolyticus. Multiple Coprothermobacter-affiliated strains were detected, introducing an additional level of complexity seldom explored in biogas studies. Genome reconstructions provided metabolic insight into the microbes that performed biomass deconstruction and fermentation, including the deeply branching phyla Dictyoglomi and Planctomycetes and the candidate phylum "Atribacteria" These biomass degraders were complemented by a synergistic network of microorganisms that convert key fermentation intermediates (fatty acids) via syntrophic interactions with hydrogenotrophic methanogens to ultimately produce methane. Interpretation of the proteomics data also suggested activity of a Methanosaeta phylotype acclimatized to high ammonia levels. In particular, we report multiple novel phylotypes proposed as syntrophic acetate oxidizers, which also exert expression of enzymes needed for both the Wood-Ljungdahl pathway and β-oxidation of fatty acids to acetyl coenzyme A. Such an arrangement differs from known syntrophic oxidizing bacteria and presents an interesting hypothesis for future studies. Collectively, these findings provide increased insight into active metabolic roles of uncultured phylotypes and presents new synergistic relationships, both of which may contribute to the stability of the biogas reactor. Biogas production through anaerobic digestion of organic waste provides an attractive source of renewable energy and a sustainable waste management strategy. A comprehensive understanding

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

    NARCIS (Netherlands)

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

    2002-01-01

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

  16. Kinetics of butyrate, acetate, and hydrogen metabolism in a thermophilic, anaerobic, butyrate-degrading triculture.

    Science.gov (United States)

    Ahring, B K; Westermann, P

    1987-02-01

    Kinetics of butyrate, acetate, and hydrogen metabolism were determined with butyrate-limited, chemostat-grown tricultures of a thermophilic butyrate-utilizing bacterium together with Methanobacterium thermoautotrophicum and the TAM organism, a thermophilic acetate-utilizing methanogenic rod. Kinetic parameters were determined from progress curves fitted to the integrated form of the Michaelis-Menten equation. The apparent half-saturation constants, K(m), for butyrate, acetate, and dissolved hydrogen were 76 muM, 0.4 mM, and 8.5 muM, respectively. Butyrate and hydrogen were metabolized to a concentration of less than 1 muM, whereas acetate uptake usually ceased at a concentration of 25 to 75 muM, indicating a threshold level for acetate uptake. No significant differences in K(m) values for butyrate degradation were found between chemostat- and batch-grown tricultures, although the maximum growth rate was somewhat higher in the batch cultures in which the medium was supplemented with yeast extract. Acetate utilization was found to be the rate-limiting reaction for complete degradation of butyrate to methane and carbon dioxide in continuous culture. Increasing the dilution rate resulted in a gradual accumulation of acetate. The results explain the low concentrations of butyrate and hydrogen normally found during anaerobic digestion and the observation that acetate is the first volatile fatty acid to accumulate upon a decrease in retention time or increase in organic loading of a digestor.

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

    DEFF Research Database (Denmark)

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

    2002-01-01

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

  18. Characterization of the planktonic microbiome in upflow anaerobic sludge blanket reactors during adaptation of mesophilic methanogenic granules to thermophilic operational conditions

    DEFF Research Database (Denmark)

    Zhu, Xinyu; Treu, Laura; Kougias, Panagiotis

    2017-01-01

    Upflow anaerobic sludge blanket (UASB) technology refers to reactor technology where granules, i.e. self-immobilised microbial associations, are the biological catalysts involved in the anaerobic digestion process. During the start-up period, UASB reactors operate at relatively long HRT and there......Upflow anaerobic sludge blanket (UASB) technology refers to reactor technology where granules, i.e. self-immobilised microbial associations, are the biological catalysts involved in the anaerobic digestion process. During the start-up period, UASB reactors operate at relatively long HRT...... and therefore the liquid phase of the reactor becomes a favourable environment for microbial growth. The current study aimed to elucidate the dynamicity of the suspended microbial community in UASB reactors, during the transition from mesophilic to thermophilic conditions. High throughput 16S rRNA amplicon...... sequencing was used to characterize the taxonomic composition of the microbiome. The results showed that the microbial community was mainly composed by hydrolytic and fermentative bacteria. Results revealed relevant shifts in the microbial community composition, which is mainly determined by the operational...

  19. Improved anaerobic biodegradation of biosolids by the addition of food waste as a co-substrate

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H.-W.; Han, S.-K.; Song, Y.-C.; Baek, B.-C.; Yoo, K.-S.; Lee, J.-J.; Shin, H.-S.

    2003-07-01

    The temperature phased anaerobic digestion (TPAD) process was applied to increase the performance of anaerobic treatment of biosolids. Previously obtained results indicate that this system showed the advantages of thermophilic and mesophilic anaerobic digestion process. By comparing the performance of each reactor of the system, it was illustrated that the main stage of methane production was the thermophilic reactor which has faster microbial metabolism. However, the result revealed that substrate characteristics of low VS/TS limited the system performance. Therefore, to evaluate the effect of food waste as a co-substrate for improving anaerobic biodegradability, biochemical methane potential (BMP) tests were conducted in thermophilic conditions with biomass of thermophilic reactor. It was confirmed that the co-digestion of sewage sludge mixed with food waste had a distinct improvement on biodegradability. The most significant advantages were the preferable environment provided by food waste for the growth and activity of anaerobes and the mutual assistance between biosolids and food waste. (author)

  20. Analysis of methanogenic activity in a thermophilic-dry anaerobic reactor: Use of fluorescent in situ hybridization

    International Nuclear Information System (INIS)

    Montero, B.; Garcia-Morales, J.L.; Sales, D.; Solera, R.

    2009-01-01

    Methanogenic activity in a thermophilic-dry anaerobic reactor was determined by comparing the amount of methane generated for each of the organic loading rates with the size of the total and specific methanogenic population, as determined by fluorescent in situ hybridization. A high correlation was evident between the total methanogenic activity and retention time [-0.6988Ln(x) + 2.667] (R 2 0.8866). The total methanogenic activity increased from 0.04 x 10 -8 mLCH 4 cell -1 day -1 to 0.38 x 10 -8 mLCH 4 cell -1 day -1 while the retention time decreased, augmenting the organic loading rates. The specific methanogenic activities of H 2 -utilizing methanogens and acetate-utilizing methanogens increased until they stabilised at 0.64 x 10 -8 mLCH 4 cell -1 day -1 and 0.33 x 10 -8 mLCH 4 cell -1 day -1 , respectively. The methanogenic activity of H 2 -utilizing methanogens was higher than acetate-utilizing methanogens, indicating that maintaining a low partial pressure of hydrogen does not inhibit the acetoclastic methanogenesis or the anaerobic process

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

    Science.gov (United States)

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

    2013-12-01

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

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

    Science.gov (United States)

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

    2016-11-17

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

  3. Growing Chlorella vulgaris on thermophilic anaerobic digestion swine manure for nutrient removal and biomass production.

    Science.gov (United States)

    Deng, Xiang-Yuan; Gao, Kun; Zhang, Ren-Chuan; Addy, Min; Lu, Qian; Ren, Hong-Yan; Chen, Paul; Liu, Yu-Huan; Ruan, Roger

    2017-11-01

    Liquid swine manure was subjected to thermophilic anaerobic digestion, ammonia stripping and centrifugation in order to increase the available carbon sources and decrease the ammonia concentration and turbidity. Chlorella vulgaris (UTEX 2714) was grown on minimally diluted (2×, 3× and 4×) autoclaved and non-autoclaved pretreated anaerobic digestion swine manure (PADSM) in a batch-culture system for 7days. Results showed that C. vulgaris (UTEX 2714) grew best on 3× PADSM media, and effectively removed NH 4 + -N, TN, TP and COD by 98.5-99.8%, 49.2-55.4%, 20.0-29.7%, 31.2-34.0% and 99.8-99.9%, 67.4-70.8%, 49.3-54.4%, 73.6-78.7% in differently diluted autoclaved and non-autoclaved PADSM, respectively. Results of chemical compositions indicated that contents of pigment, carbohydrate, protein and lipid in C. vulgaris (UTEX 2714) changed with the culture conditions. Moreover, its fatty acid profiles suggested that this alga could be used as animal feed if cultivated in autoclaved PADSM or as good-quality biodiesel feedstock if cultivated in non-autoclaved PADSM. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    DEFF Research Database (Denmark)

    Uellendahl, Hinrich; Ahring, Birgitte Kiær

    2010-01-01

    ) and mesophilic (388C) operation of the UASB reactor was investigated. At an OLR of 3.5 kg- VS/(m3 day) a methane yield of 340 L/kg-VS was achieved for thermophilic operation (538C) while 270 L/kg-VS was obtained under mesophilic conditions (388C). For loading rates higher than 5 kg-VS/(m3 day) the methane yields...... 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...

  5. Bacteria and archaea communities in full-scale thermophilic and mesophilic anaerobic digesters treating food wastewater: Key process parameters and microbial indicators of process instability.

    Science.gov (United States)

    Lee, Joonyeob; Shin, Seung Gu; Han, Gyuseong; Koo, Taewoan; Hwang, Seokhwan

    2017-12-01

    In this study, four different mesophilic and thermophilic full-scale anaerobic digesters treating food wastewater (FWW) were monitored for 1-2years in order to investigate: 1) microbial communities underpinning anaerobic digestion of FWW, 2) significant factors shaping microbial community structures, and 3) potential microbial indicators of process instability. Twenty-seven bacterial genera were identified as abundant bacteria underpinning the anaerobic digestion of FWW. Methanosaeta harundinacea, M. concilii, Methanoculleus bourgensis, M. thermophilus, and Methanobacterium beijingense were revealed as dominant methanogens. Bacterial community structures were clearly differentiated by digesters; archaeal community structures of each digester were dominated by one or two methanogen species. Temperature, ammonia, propionate, Na + , and acetate in the digester were significant factors shaping microbial community structures. The total microbial populations, microbial diversity, and specific bacteria genera showed potential as indicators of process instability in the anaerobic digestion of FWW. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. 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.

  7. 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

    2016-07-22

    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.

  8. Mesophilic and thermophilic anaerobic co-digestion of winery wastewater sludge and wine lees: An integrated approach for sustainable wine production.

    Science.gov (United States)

    Da Ros, C; Cavinato, C; Pavan, P; Bolzonella, D

    2017-12-01

    In this work, winery wastes generated by a cellar producing approximately 300,000 hL of wine per year was monitored for a period of one year. On average, 196 L of wastewater, 0.1 kg of waste activated sludge (dry matter) and 1.6 kg of wine lees were produced per hectoliter of wine produced. Different winery wastes, deriving from different production steps, namely waste activated sludge from wastewater treatment and wine lees, were co-treated using an anaerobic digestion process. Testing was conducted on a pilot scale for both mesophilic and thermophilic conditions. The process was stable for a long period at 37 °C, with an average biogas production of 0.386 m 3 /kg COD fed . On the other hand, for thermophilic conditions, volatile fatty acids accumulated in the reactor and the process failed after one hydraulic retention time (23 days). In order to fix the biological process, trace elements (iron, cobalt and nickel) were added to the feed of the thermophilic reactor. Metals augmentation improved process stability and yields at 55 °C. The pH ranged between 7.8 and 8.0, and specific gas production was 0.450 m 3 /kg COD fed , which corresponded to dry matter and COD removals of 34% and 88%, respectively. Although the observed performances in terms of biogas production were good, the thermophilic process exhibited some limitations related to both the necessity of metals addition and the worse dewaterability properties. In fact, while the mesophilic digestates reached a good dewatering quality via the addition of 6.5 g of polymer per kg of dry matter, the required dosage for the thermophilic sludge was greater than 10 g/kg of dry matter. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Effects of hydrogen and formate on the degradation of propionate and butyrate in thermophilic granules from an upflow anaerobic sludge blanket reactor.

    OpenAIRE

    Schmidt, J E; Ahring, B K

    1993-01-01

    Degradation of propionate and butyrate in whole and disintegrated granules from a thermophilic (55 degrees C) upflow anaerobic sludge blanket reactor fed with acetate, propionate, and butyrate as substrates was examined. The propionate and butyrate degradation rates in whole granules were 1.16 and 4.0 mumol/min/g of volatile solids, respectively, and the rates decreased 35 and 25%, respectively, after disintegration of the granules. The effect of adding different hydrogen-oxidizing bacteria (...

  10. 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.

  11. 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

    2016-01-01

    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. PMID:27444518

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

    International Nuclear Information System (INIS)

    Sajeena Beevi, B.; Madhu, G.; Sahoo, Deepak Kumar

    2015-01-01

    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 −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 −1

  13. 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}.

  14. Hydrogenomics of the extremely thermophilic bacterium Caldicellulosiruptor saccharolyticus

    NARCIS (Netherlands)

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

    2008-01-01

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

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

    OpenAIRE

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

    1992-01-01

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

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

    Science.gov (United States)

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

    2014-01-15

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

  17. Recent developments in the thermophilic microbiology of deep-sea hydrothermal vents.

    Science.gov (United States)

    Miroshnichenko, Margarita L; Bonch-Osmolovskaya, Elizaveta A

    2006-04-01

    The diversity of thermophilic prokaryotes inhabiting deep-sea hot vents was actively studied over the last two decades. The ever growing interest is reflected in the exponentially increasing number of novel thermophilic genera described. The goal of this paper is to survey the progress in this field made in the years 2000-2005. In this period, representatives of several new taxa of hyperthermophilic archaea were obtained from deep-sea environments. Two of these isolates had phenotypic features new for this group of organisms: the presence of an outer cell membrane (the genus Ignicoccus) and the ability to grow anaerobically with acetate and ferric iron (the genus Geoglobus). Also, our knowledge on the diversity of thermophilic bacteria from deep-sea thermal environments extended significantly. The new bacterial isolates represented diverse bacterial divisions: the phylum Aquificae, the subclass Epsilonproteobacteria, the order Thermotogales, the families Thermodesulfobacteriaceae, Deferribacteraceae, and Thermaceae, and a novel bacterial phylum represented by the genus Caldithrix. Most of these isolates are obligate or facultative lithotrophs, oxidizing molecular hydrogen in the course of different types of anaerobic respiration or microaerobic growth. The existence and significant ecological role of some of new bacterial thermophilic isolates was initially established by molecular methods.

  18. 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

    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......Thermophilic ethanol fermentation of wet-exploded wheat straw hydrolysate was investigated in a continuous immobilized reactor system. The experiments were carried out in a lab-scale fluidized bed reactor (FBR) at 70C. Undetoxified wheat straw hydrolysate was used (3-12% dry matter), corresponding...... 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...

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

    Science.gov (United States)

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

    2018-01-01

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

  20. 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)

    Silvestre, G.; Illa, J.; Fernández, B.; Bonmatí, A.

    2014-01-01

    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 kg COD 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

  1. Ethanol and anaerobic conditions reversibly inhibit commercial cellulase activity in thermophilic simultaneous saccharification and fermentation (tSSF

    Directory of Open Access Journals (Sweden)

    Podkaminer Kara K

    2012-06-01

    Full Text Available Abstract Background A previously developed mathematical model of low solids thermophilic simultaneous saccharification and fermentation (tSSF with Avicel was unable to predict performance at high solids using a commercial cellulase preparation (Spezyme CP and the high ethanol yield Thermoanaerobacterium saccharolyticum strain ALK2. The observed hydrolysis proceeded more slowly than predicted at solids concentrations greater than 50 g/L Avicel. Factors responsible for this inaccuracy were investigated in this study. Results Ethanol dramatically reduced cellulase activity in tSSF. At an Avicel concentration of 20 g/L, the addition of ethanol decreased conversion at 96 hours, from 75% in the absence of added ethanol down to 32% with the addition of 34 g/L initial ethanol. This decrease is much greater than expected based on hydrolysis inhibition results in the absence of a fermenting organism. The enhanced effects of ethanol were attributed to the reduced, anaerobic conditions of tSSF, which were shown to inhibit cellulase activity relative to hydrolysis under aerobic conditions. Cellulose hydrolysis in anaerobic conditions was roughly 30% slower than in the presence of air. However, this anaerobic inhibition was reversed by exposing the cellulase enzymes to air. Conclusion This work demonstrates a previously unrecognized incompatibility of enzymes secreted by an aerobic fungus with the fermentation conditions of an anaerobic bacterium and suggests that enzymes better suited to industrially relevant fermentation conditions would be valuable. The effects observed may be due to inactivation or starvation of oxygen dependent GH61 activity, and manipulation or replacement of this activity may provide an opportunity to improve biomass to fuel process efficiency.

  2. Thermal pre-treatment of primary and secondary sludge at 70ºC prior to anaerobic digestion

    DEFF Research Database (Denmark)

    Skiadas, Ioannis V.; Gavala, H.N.; Lu, Jingquan

    2005-01-01

    . The present study investigates the effect of the pre-treatment at 70 degrees C on thermophilic (55 degrees C) anaerobic digestion of primary and secondary sludge in continuously operated digesters. Thermal pre-treatment of primary and secondary sludge at 70 degrees C enhanced the removal of organic matter...... and the methane production during the subsequent anaerobic digestion step at 55 degrees C. It also greatly contributed to the destruction of pathogens present in primary sludge. Finally it results in enhanced microbial activities of the subsequent anaerobic step suggesting that the same efficiencies in organic...... matter removal and methane recovery could be obtained at lower HRTs....

  3. Modelling the competition between sulphate reducers and methanogens in a thermophilic methanol-fed bioreactor

    NARCIS (Netherlands)

    Spanjers, H.; Weijma, J.; Abusam, A.

    2002-01-01

    Sulphate can be removed from wastewater by means of biological anaerobic reduction to sulphide. The reduction requires the presence of a substrate that can serve as an electron donor. Methanol a suitable electron donor for sulphate reduction under thermophilic conditions. In an anaerobic system

  4. Moroccan rock phosphate solubilization during a thermo-anaerobic ...

    African Journals Online (AJOL)

    In order to investigate the presence of thermo-tolerant rock phosphate (RP) solubilizing anaerobic microbes during the fermentation process, we used grassland as sole organic substrate to evaluate the RP solubilization process under anaerobic thermophilic conditions. The result shows a significant decrease of pH from ...

  5. Comparison of bacterial community structure and dynamics during the thermophilic composting of different types of solid wastes: anaerobic digestion residue, pig manure and chicken manure

    OpenAIRE

    Song, Caihong; Li, Mingxiao; Jia, Xuan; Wei, Zimin; Zhao, Yue; Xi, Beidou; Zhu, Chaowei; Liu, Dongming

    2015-01-01

    This study investigated the impact of composting substrate types on the bacterial community structure and dynamics during composting processes. To this end, pig manure (PM), chicken manure (CM), a mixture of PM and CM (PM + CM), and a mixture of PM, CM and anaerobic digestion residue (ADR) (PM + CM + ADR) were selected for thermophilic composting. The bacterial community structure and dynamics during the composting process were detected and analysed by polymerase chain reaction–denaturing gra...

  6. Bicarbonate dosing: a tool to performance recovery of a thermophilic methanol-fed UASB reactor

    NARCIS (Netherlands)

    Paulo, P.L.; Lier, van J.B.; Lettinga, G.

    2003-01-01

    The thermophilic-anaerobic treatment of methanol-containing wastewater in an upflow anaerobic sludge blanket (UASB) reactor, was found to be quite sensitive to pH shocks, both acid and alkaline. The results of the recovery experiments of sludge exposed to an alkaline shock, indicated that the

  7. Economic Feasibility of Installing an Anaerobic Digester on a Department of Defense Installation

    Science.gov (United States)

    2010-03-01

    permits anaerobic bacteria and enzymes to affect more waste than a lagoon does, as well as preventing a film or layer of scum forming on top of the waste...temperature classifications for anaerobic digestion. The three classes listed are: psychrophilic (4- 20 C), mesophilic (20-45 C), and thermophilic (45-60...operated at 55º C, 30 focusing on an optimum temperature for thermophilic bacteria. Despite previously discussed percentages for total solids in

  8. Use of respirometer in evaluation of process and toxicity of thermophilic anaerobic digestion for treating kitchen waste.

    Science.gov (United States)

    Kuo, Wen-Chien; Cheng, Kae-Yiin

    2007-07-01

    A thermophilic anaerobic digestion (TAnD, 55 degrees C) system was adopted to hydrolyze the kitchen waste for 3 days, which was then fermented for a hydraulic retention time (HRT) of 10 days. The TAnD system performed much better than a similar system without thermal pre-treatment. A bubble respirometer was employed to study the effects of thermal pre-treatment, which showed that pre-treatment at 60 degrees C yielded the highest Total COD (TCOD) removal efficiency (79.2%) after 300h reaction. Respirometer results also indicated that oil and grease (O and G) began to inhibit the TAnD system at a concentration of approximately 1000mg/L and the gas production was inhibited by 50% at a concentration of approximately 7500mg/L of sodium.

  9. 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

  10. Inhibitory effects on anaerobic digestion of swine manure

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, P.W.S.; Zhou, H. [Univ. of Guelph, School of Engineering, Guelph, Ontario (Canada)]. E-mail: hzhou@uoguelph.ca; Hacker, R. [Univ. of Guelph, Dept. of Animal and Poultry Science, Guelph, Ontario (Canada)

    2002-06-15

    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)

  11. Inhibitory effects on anaerobic digestion of swine manure

    International Nuclear Information System (INIS)

    Cheung, P.W.S.; Zhou, H.; Hacker, R.

    2002-01-01

    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)

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

    DEFF Research Database (Denmark)

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

    2011-01-01

    The two-stage process for extreme thermophilic hydrogen and thermophilic methane production from wheat straw hydrolysate was investigated in up-flow anaerobic sludge bed (UASB) reactors. Specific hydrogen and methane yields of 89ml-H2/g-VS (190ml-H2/g-sugars) and 307ml-CH4/g-VS, respectively were...... energy of 13.4kJ/g-VS. Dominant hydrogen-producing bacteria in the H2-UASB reactor were Thermoanaerobacter wiegelii, Caldanaerobacter subteraneus, and Caloramator fervidus. Meanwhile, the CH4-UASB reactor was dominated with methanogens of Methanosarcina mazei and Methanothermobacter defluvii. The results...

  13. Comparison of multi-enzyme and thermophilic bacteria on the hydrolysis of mariculture organic waste (MOW).

    Science.gov (United States)

    Guo, Liang; Sun, Mei; Zong, Yan; Zhao, Yangguo; Gao, Mengchun; She, Zonglian

    2016-01-01

    Mariculture organic waste (MOW) is rich in organic matter, which is a potential energy resource for anaerobic digestion. In order to enhance the anaerobic fermentation, the MOW was hydrolyzed by multi-enzyme and thermophilic bacteria. It was advantageous for soluble chemical oxygen demand (SCOD) release at MOW concentrations of 6 and 10 g/L with multi-enzyme and thermophilic bacteria pretreatments. For multi-enzyme, the hydrolysis was not obvious at substrate concentrations of 1 and 3 g/L, and the protein and carbohydrate increased with hydrolysis time at substrate concentrations of 6 and 10 g/L. For thermophilic bacteria, the carbohydrate was first released at 2-4 h and then consumed, and the protein increased with hydrolysis time. The optimal enzyme hydrolysis for MOW was determined by measuring the changes of SCOD, protein, carbohydrate, ammonia and total phosphorus, and comparing with acid and alkaline pretreatments.

  14. 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

    A limited number of bacteria, yeast and fungi can convert hemicellulose or its monomers (xylose, arabinose, mannose and galactose) into ethanol with a satisfactory yield and productivity. In the present study we tested a number of thermophilic enrichment cultures, and new isolates of thermophilic...... Of D-Xylose into ethanol; (ii) test for viability and ethanol production in pretreated wheat straw hemicellulose hydrolysate; (iii) test for tolerance against high D-xylose concentrations. A total of 86 enrichment cultures and 58 pure cultures were tested and five candidates were selected which...

  15. 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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. The chemical properties and microbial community characterization of the thermophilic microaerobic pretreatment process.

    Science.gov (United States)

    Fu, Shan-Fei; He, Shuai; Shi, Xiao-Shuang; Katukuri, Naveen Reddy; Dai, Meng; Guo, Rong-Bo

    2015-12-01

    Thermophilic microaerobic pretreatment (TMP) was recently reported as an efficient pretreatment method of anaerobic digestion (AD). In this study, the chemical properties and microbial community were characterized to reveal how TMP working. Compared with thermophilic treatment under anaerobic condition (TMP0), cellulase activity obviously improved under microaerobic condition (TMP1), which was 10.9-49.0% higher than that of TMP0. Reducing sugar, SCOD and VFAs concentrations of TMP1 were 2.6-8.9%, 1.8-4.8% and 13.8-24% higher than those of TMP0, respectively. TMP gave obvious rise to phylum Firmicutes, which associated with extracellular enzymes production. The proportion of class Bacilli (belongs to phylum Firmicutes and mainly acts during hydrolysis) in TMP1 was 124.89% higher than that of TMP0, which reflected the greater hydrolytic ability under microaerobic condition. The improved abundance of phylum Firmicutes (especially class Bacilli, order Bacillales) under microaerobic condition could be the fundamental reason for the improved AD performance of thermophilic microaerobic pretreated corn straw. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Enrichment of acetogenic bacteria in high rate anaerobic reactors under mesophilic and thermophilic conditions.

    Science.gov (United States)

    Ryan, P; Forbes, C; McHugh, S; O'Reilly, C; Fleming, G T A; Colleran, E

    2010-07-01

    The objective of the current study was to expand the knowledge of the role of acetogenic Bacteria in high rate anaerobic digesters. To this end, acetogens were enriched by supplying a variety of acetogenic growth supportive substrates to two laboratory scale high rate upflow anaerobic sludge bed (UASB) reactors operated at 37 degrees C (R1) and 55 degrees C (R2). The reactors were initially fed a glucose/acetate influent. Having achieved high operational performance and granular sludge development and activity, both reactors were changed to homoacetogenic bacterial substrates on day 373 of the trial. The reactors were initially fed with sodium vanillate as a sole substrate. Although % COD removal indicated that the 55 degrees C reactor out performed the 37 degrees C reactor, effluent acetate levels from R2 were generally higher than from R1, reaching values as high as 5023 mg l(-1). Homoacetogenic activity in both reactors was confirmed on day 419 by specific acetogenic activity (SAA) measurement, with higher values obtained for R2 than R1. Sodium formate was introduced as sole substrate to both reactors on day 464. It was found that formate supported acetogenic activity at both temperatures. By the end of the trial, no specific methanogenic activity (SMA) was observed against acetate and propionate indicating that the methane produced was solely by hydrogenotrophic Archaea. Higher SMA and SAA values against H(2)/CO(2) suggested development of a formate utilising acetogenic population growing in syntrophy with hydrogenotrophic methanogens. Throughout the formate trial, the mesophilic reactor performed better overall than the thermophilic reactor. Copyright 2010 Elsevier Ltd. All rights reserved.

  18. Thermophilic fermentative hydrogen production from starch-wastewater with bio-granules

    Energy Technology Data Exchange (ETDEWEB)

    Akutsu, Yohei; Harada, Hideki [Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Sendai, Miyagi 980-8579 (Japan); Lee, Dong-Yeol [Research Center for Material Cycles and Waste Management, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 (Japan); Chi, Yong-Zhi [Department of Environmental and Municipal Engineering, Tianjin Institute of Urban Construction, Jinjinggonglu 26, Tianjin 300384 (China); Li, Yu-You [Department of Environmental and Municipal Engineering, Tianjin Institute of Urban Construction, Jinjinggonglu 26, Tianjin 300384 (China); Department of Environmental Science, Tohoku University, 6-6-06 Aoba, Sendai, Miyagi 980-8579 (Japan); Yu, Han-Qing [School of Chemistry, University of Science and Technology of China, Hefei 230026 (China)

    2009-06-15

    In this study, the effects of the hydraulic retention time (HRT), pH and substrate concentration on the thermophilic hydrogen production of starch with an upflow anaerobic sludge bed (UASB) reactor were investigated. Starch was used as a sole substrate. Continuous hydrogen production was stably attained with a maximum H{sub 2} yield of 1.7 mol H{sub 2}/mol glucose. A H{sub 2}-producing thermophilic granule was successfully formed with diameter in the range of 0.5-4.0 mm with thermally pretreated methanogenic granules as the nuclei. The metabolic pathway of the granules was drastically changed at each operational parameter. The production of formic or lactic acids is an indication of the deterioration of hydrogen production for H{sub 2}-producing thermophilic granular sludge. (author)

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

    NARCIS (Netherlands)

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

    2003-01-01

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

  20. 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.

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

    KAUST Repository

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

    2012-01-01

    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.

  2. 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...... ammonium bicarbonate additions. Dilution of SS-OFMSW with fresh water showed a stable performance with volatile fatty acids of solids (VS). Use of recirculated process water after stripping ammonia showed even better performance with a methane yield...... of 0.43 m(3) kg(-1)VS. Recirculation of process water alone on the other hand, resulted in process inhibition at both TAN levels of 3.5 and 5.5 g-N l(-1). However, after a short period, the process recovered and adapted to the tested TAN levels. Thus, use of recirculated process water after stripping...

  3. Fertilizer potential of liquid and solid effluent from thermophilic anaerobic digestion of poultry waste.

    Science.gov (United States)

    Liedl, B E; Bombardiere, J; Chaffield, J M

    2006-01-01

    Thermophilic anaerobic treatment of poultry litter produces an effluent stream of digested materials that can be separated into solid and liquid fractions for use as a crop fertilizer. The majority of the phosphorus is partitioned into the solid fraction while the majority of the nitrogen is present in the liquid fraction in the form of ammonium. These materials were tested over six years as an alternative fertilizer for the production of vegetable, fruit, and grassland crops. Application of the solids as a field crop fertilizer for vegetables and blueberries resulted in lower yields than the other fertilizer treatments, but an increase in soil phosphorus over a four-year period. Application of the digested liquids on grass and vegetable plots resulted in similar or superior yields to plots treated with commercially available nitrogen fertilizers. Hydroponic production of lettuce using liquid effluent was comparable to a commercial hydroponic fertilizer regime; however, the effluent treatment for hydroponic tomato production required supplementation and conversion of ammonium to nitrate. While not a total fertilizer solution, our research shows the effectiveness of digested effluent as part of a nutrient management program which could turn a livestock residuals problem into a crop nutrient resource.

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

    Science.gov (United States)

    Summit, Melanie; Baross, John A.

    1998-12-01

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

  5. Dry thermophilic semi-continuous anaerobic digestion of food waste: Performance evaluation, modified Gompertz model analysis, and energy balance

    International Nuclear Information System (INIS)

    Nguyen, Dinh Duc; Chang, Soon Woong; Jeong, Seong Yeob; Jeung, Jaehoon; Kim, Sungsu; Guo, Wenshan; Ngo, Huu Hao

    2016-01-01

    Highlights: • Energy self-sufficiency/energy recovery with thermophilic DScAD of FW was evaluated. • The maximum biogas production rate was positively influenced by OLRs. • Maximum (average) electrical energy recoverable from a 1 tons of FW was 1050 kW h. • Thermophilic DScAD can substantially reduce the VS and recover energy to serve itself. • A modified Gompertz model fitted well with the experimental results for all phases. - Abstract: A thermophilic, dry semi-continuous anaerobic digestion (DScAD) method was used to effectively transform food waste (FW) into renewable energy. This study aims to thoroughly evaluate the system performance and model simulation to predict biogas production, intermediate products and their outcomes, energy recovery potential, and energy balance, while operating with organic loading rates ranging from 2.3 to 9.21 kg-TS/m"3 day. The results indicate that volatile solids (VS) reduction and biogas production both improved as the organic loading rates (OLR) increased, and the cost of FW valorization remained low. The greatest VS reduction achieved was 87.01%, associated with 170 m"3 of biogas yield per ton of sludge (69% methane) at an ORL of 9.21 ± 0.89 kg-TS/m"3 day (8.62 ± 0.34 kg-VS/m"3 day) although the amounts of ammonia (3700 mg/L), hydrogen sulfide (420 ppm), and total volatile fatty acids (7101 mg/L) during fermentation were relatively high. Furthermore, 75% of total energy requirement for the system could be recovered via biomethane production, resulting in a considerably reduced specific energy supply (kW h/ton of treating FW). The results suggest that a modified Gompertz model is suitable for estimating the biogas and methane production potential and rate. The results also reveal that the DScAD of FW at 55 °C is a reliable, stable, and robust option for both solids reduction and energy recovery via biogas generation.

  6. Effect of temperature on removal of antibiotic resistance genes by anaerobic digestion of activated sludge revealed by metagenomic approach.

    Science.gov (United States)

    Zhang, Tong; Yang, Ying; Pruden, Amy

    2015-09-01

    As antibiotic resistance continues to spread globally, there is growing interest in the potential to limit the spread of antibiotic resistance genes (ARGs) from wastewater sources. In particular, operational conditions during sludge digestion may serve to discourage selection of resistant bacteria, reduce horizontal transfer of ARGs, and aid in hydrolysis of DNA. This study applied metagenomic analysis to examine the removal efficiency of ARGs through thermophilic and mesophilic anaerobic digestion using bench-scale reactors. Although the relative abundance of various ARGs shifted from influent to effluent sludge, there was no measureable change in the abundance of total ARGs or their diversity in either the thermophilic or mesophilic treatment. Among the 35 major ARG subtypes detected in feed sludge, substantial reductions (removal efficiency >90%) of 8 and 13 ARGs were achieved by thermophilic and mesophilic digestion, respectively. However, resistance genes of aadA, macB, and sul1 were enriched during the thermophilic anaerobic digestion, while resistance genes of erythromycin esterase type I, sul1, and tetM were enriched during the mesophilic anaerobic digestion. Efflux pump remained to be the major antibiotic resistance mechanism in sludge samples, but the portion of ARGs encoding resistance via target modification increased in the anaerobically digested sludge relative to the feed. Metagenomic analysis provided insight into the potential for anaerobic digestion to mitigate a broad array of ARGs.

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

    Science.gov (United States)

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

    2013-02-28

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

  8. Starch-degrading enzymes from anaerobic non-clostridial bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Weber, H; Schepers, H J; Troesch, W [Fraunhofer-Institut fuer Grenzflaechen- und Bioverfahrenstechnik (IGB), Stuttgart (Germany, F.R.)

    1990-08-01

    A number of meso- and thermophilic anaerobic starch-degrading non-spore-forming bacteria have been isolated. All the isolates belonging to different genera are strictly anaerobic, as indicated by a catalase-negative reaction, and produce soluble starch-degrading enzymes. Compared to enzymes of aerobic bacteria, those of anaerobic origin mainly show low molecular mass of about 25 000 daltons. Some of the enzymes may have useful applications in the starch industry because of their unusual product pattern, yielding maltotetraose as the main hydrolysis product. (orig.).

  9. Thermophilic anaerobic co-digestion of poultry litter and thin stillage.

    Science.gov (United States)

    Sharma, Deepak; Espinosa-Solares, Teodoro; Huber, David H

    2013-05-01

    The purpose of this study was to test whether the performance of a thermophilic CSTR digester that has been stabilized on poultry litter will be enhanced or diminished by the addition of thin stillage as co-substrate. Replicate laboratory digesters, derived from a stable pilot-scale digester, were operated with increasing ratios (w/w) of thin stillage/poultry litter feedstock. After a period of adaptation to 20% and 40% thin stillage, digester performance showed increases in biogas, percent methane and COD removal, as well as a decrease in volatile acids. Peak performance occurred with 60% thin stillage. However, 80% thin stillage caused significant reduction of performance, including declines of methanogenic activity and COD removal. In conclusion, supplementing the thermophilic digestion of poultry litter with thin stillage improved the bioenergy (methane) output, but thin stillage became inhibitory at high concentrations. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. γ-irradiation resistance and UV-sensitivity of extremely thermophilic archebacteria and eubacteria

    International Nuclear Information System (INIS)

    Kopylov, V.M.; Bonch-Osmolovskaya, E.A.; Svetlichnyi, V.A.; Miroshnichenko, M.L.; Skobkin, V.S.

    1993-01-01

    Cells of extremely thermophilic sulfur-dependent archebacteria Desulfurococcus amylolyticus Z533 and Thermococcus stelleri K15 are resistant to γ-irradiation. These archebacteria survive γ-irradiation at a dose of up to 5 kGy but are no longer viable after 8-9 kGy. Comparison of the survival profiles showed that archebacteria are 12 to 25 times more resistant to γ-irradiation at moderate doses (LD 50 and LD 90 ) than E. coli K12 but are 2 to 2.5 times more sensitive than D. radiodurans. γ-irradiation at a dose of 1 to 2.5 kGy killed extremely thermophilic anaerobic eubacteria Thermotoga maritima 2706 and Thermodesulfobacterium P. All extreme thermophiles studied were more sensitive to UV-irradiation than E. coli

  11. Characterization of technetium(vII) reduction by cell suspensions of thermophilic bacteria and archaea.

    Science.gov (United States)

    Chernyh, Nikolay A; Gavrilov, Sergei N; Sorokin, Vladimir V; German, Konstantin E; Sergeant, Claire; Simonoff, Monique; Robb, Frank; Slobodkin, Alexander I

    2007-08-01

    Washed cell suspensions of the anaerobic hyperthermophilic archaea Thermococcus pacificus and Thermoproteus uzoniensis and the anaerobic thermophilic gram-positive bacteria Thermoterrabacterium ferrireducens and Tepidibacter thalassicus reduced technetium [(99)Tc(VII)], supplied as soluble pertechnetate with molecular hydrogen as an electron donor, forming highly insoluble Tc(IV)-containing grayish-black precipitate. Apart from molecular hydrogen, T. ferrireducens reduced Tc(VII) with lactate, glycerol, and yeast extract as electron donors, and T. thalassicus reduced it with peptone. Scanning electron microscopy and X-ray microanalysis of cell suspensions of T. ferrireducens showed the presence of Tc-containing particles attached to the surfaces of non-lysed cells. This is the first report on the reduction in Tc(VII) by thermophilic microorganisms of the domain Bacteria and by archaea of the phylum Euryarchaeota.

  12. Complete Genome Sequence of the Anaerobic Halophilic Alkalithermophile Natranaerobius thermophilus JW/NM-WN-LFT

    Energy Technology Data Exchange (ETDEWEB)

    Mesbah, Noha [University of Georgia, Athens, GA; Dalin, Eileen [U.S. Department of Energy, Joint Genome Institute; Goodwin, Lynne A. [Los Alamos National Laboratory (LANL); Nolan, Matt [U.S. Department of Energy, Joint Genome Institute; Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Chertkov, Olga [Los Alamos National Laboratory (LANL); Han, James [U.S. Department of Energy, Joint Genome Institute; Larimer, Frank W [ORNL; Land, Miriam L [ORNL; Hauser, Loren John [ORNL; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Wiegel, Juergen [University of Georgia, Athens, GA

    2011-01-01

    The genome of the anaerobic halophilic alkalithermophile Natranaerobius thermophiles consists of one chromosome and two plasmids.The present study is the first to report the completely sequenced genome of polyextremophile and the harboring genes harboring genes associated with roles in regulation of intracellular osmotic pressure, pH homeostasis, and thermophilic stability.

  13. Effects of continuous addition of nitrate to a thermophilic anaerobic digestion system

    International Nuclear Information System (INIS)

    Rivard, C.J.

    1983-01-01

    The biodegradation of complex organic matter is regulated partially by the ability to dump electrons which build up in the form of reduced nicotinamide adenine dinucleotide (NAD). The effects of the continuous addition of the oxidant, nitrate, were investigated on a single-stage, thermophilic, anaerobic digester. The digester acclimated rapidly to nitrate addition. The continuous addition of nitrate resulted in a constant inhibition of total gas (30%) and methane production (36%). Reduction in total gas and methane production was accompanied by increases in sludge pH and acetate, propionate, and ammonium ion pools. Effluent particle size distribution revealed a shift to smaller particle sizes in the nitrate-pumped sludge. The continuous addition of nitrate resulted in lower numbers of methanogens and sulfate reducers in the sludge, with increases in nitrate-reducing and cellulose-degrading microorganisms. These findings indicate that added nitrate underwent dissimilatory reduction to ammonium ion, as determined from gas analysis, ammonium pools, and 15 N-nitrate-label experiments. Continuous nitrate addition to a single-phase digestion system was determined to inhibit methane production from biomass and wastes. Thus for the single-stage digestion system in which maximum methane production is desired, the addition of nitrate is not recommended. However, in a multistage digestion system, the continuous addition of nitrate in the primary stage to increase the rate and extent of degradation of organic matter to volatile fatty acids, which then would serve as feed to a second stage, may be advantageous

  14. 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.

  15. 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. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. 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

    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....... 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...... kinetics considering the relation between LCFA inhibitory substrate concentration and specific biomass content, as an approximation to the adsorption process, improved the model fitting and provided a better insight on the physical nature of the LCFA inhibition process. (C) 2009 Elsevier Ltd. All rights...

  17. Microbiological Hydrogen Production by Anaerobic Fermentation and Photosynthetic Process

    International Nuclear Information System (INIS)

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

    2009-01-01

    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)

  18. Proceedings of the 10. world congress on anaerobic digestion 2004 : anaerobic bioconversion, answer for sustainability

    International Nuclear Information System (INIS)

    2004-01-01

    This conference reviewed the broad scope of anaerobic process-related activities taking place globally and confirmed the possibilities of using anaerobic processes to add value to industrial wastewaters, municipal solid wastes and organic wastes while minimizing pollution and greenhouse gases. It focused on biomolecular tools, instrumentation of anaerobic digestion processes, anaerobic bioremediation of chlorinated organics, and thermophilic and mesophilic digestion. Several papers focused on the feasibility of using waste products to produce hydrogen and methane for electricity generation. The sessions of the conference were entitled acidogenesis; microbial ecology; process control; sulfur content; technical development; domestic wastewater; agricultural waste; organic municipal solid wastes; instrumentation; molecular biology; sludges; agricultural feedstock; bioremediation; industrial wastewater; hydrogen production; pretreatments; sustainability; and integrated systems. The conference featured 387 posters and 192 oral presentations, of which 111 have been indexed separately for inclusion in this database. refs., tabs., figs

  19. Kinetics of Butyrate, Acetate, and Hydrogen Metabolism in a Thermophilic, Anaerobic, Butyrate-Degrading Triculture

    OpenAIRE

    Ahring, Birgitte K.; Westermann, Peter

    1987-01-01

    Kinetics of butyrate, acetate, and hydrogen metabolism were determined with butyrate-limited, chemostat-grown tricultures of a thermophilic butyrate-utilizing bacterium together with Methanobacterium thermoautotrophicum and the TAM organism, a thermophilic acetate-utilizing methanogenic rod. Kinetic parameters were determined from progress curves fitted to the integrated form of the Michaelis-Menten equation. The apparent half-saturation constants, Km, for butyrate, acetate, and dissolved hyd...

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

    Science.gov (United States)

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

    2009-04-15

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

  1. Microbial community changes in methanogenic granules during the transition from mesophilic to thermophilic conditions

    DEFF Research Database (Denmark)

    Zhu, Xinyu; Kougias, Panagiotis; Treu, Laura

    2017-01-01

    Upflow anaerobic sludge blanket (UASB) reactor is one of the most applied technologies for various high-strength wastewater treatments. The present study analysed the microbial community changes in UASB granules during the transition from mesophilic to thermophilic conditions. Dynamicity...

  2. Microbial examination of anaerobic sludge adaptation to animal slurry.

    Science.gov (United States)

    Moset, V; Cerisuelo, A; Ferrer, P; Jimenez, A; Bertolini, E; Cambra-López, M

    2014-01-01

    The objective of this study was to evaluate changes in the microbial population of anaerobic sludge digesters during the adaptation to pig slurry (PS) using quantitative real-time polymerase chain reaction (qPCR) and qualitative scanning electron microscopy (SEM). Additionally, the relationship between microbial parameters and sludge physicochemical composition and methane yield was examined. Results showed that the addition of PS to an unadapted thermophilic anaerobic digester caused an increase in volatile fatty acids (VFA) concentration, a decrease in removal efficiency and CH4 yield. Additionally, increases in total bacteria and total archaea were observed using qPCR. Scanning electron micrographs provided a general overview of the sludge's cell morphology, morphological diversity and degree of organic matter degradation. A change in microbial morphotypes from homogeneous cell morphologies to a higher morphological diversity, similar to that observed in PS, was observed with the addition of PS by SEM. Therefore, the combination of qPCR and SEM allowed expanding the knowledge about the microbial adaptation to animal slurry in thermophilic anaerobic digesters.

  3. Utilization of steam- and explosion-decompressed aspen wood by some anaerobes

    Energy Technology Data Exchange (ETDEWEB)

    Khan, A W; Asther, M; Giuliano, C

    1984-01-01

    Tests made to study the suitability of using steam- and explosion-decompressed aspen wood as a substrate in anaerobic fermentations indicated that after washing with dilute NaOH it becomes less than 80% accessible to both mesophilic and thermophilic cellulolytic anaerobes and cellulases, compared with delignified, ball-milled pulp. After washing, this material was also suitable for the single-step conversion of cellulose to EtOH using cocultures consisting of cellulolytic and EtOH-producing saccharolytic anaerobes; and without and after washing by the use of cellulolytic enzymes and ethanologenic anaerobes.

  4. 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

    In this study, we focus on production of heterologous α-amylase in the yeast Saccharomyces cerevisiae under anaerobic conditions. We compare the metabolic fluxes and transcriptional regulation under aerobic and anaerobic conditions, with the objective of identifying the final electron acceptor...... 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...... provide a model for the molecular mechanism of anaerobic protein secretion using fumarate as the final electron acceptor, which may allow for further engineering of yeast for improved protein secretion under anaerobic growth conditions....

  5. Final report on the monitoring and optimization of the anaerobic digestion of whey at Millbank Cheese and Butter Ltd

    Energy Technology Data Exchange (ETDEWEB)

    Adams, G P

    1987-03-01

    A project is described in which a full-scale anaerobic digestion facility was used to produce biogas fuel from raw whey at a cheese factory. The purpose of the project was to optimize the operation of the full-scale facility through achievement of the design loadings, thereby generating the best economic return for the facility. Several nutrient/buffer supplement additions were evaluated at lab-scale in an attempt to devise a solution for the full-scale facility. The supplements used in this study included municipal digester supernatant from a municipal wastewater treatment plant, digested swine manure from a hog farm and caustic (NaOH). In addition, the project examines the effects of operating at thermophilic (55{sup 0}) temperature, the effect of daily additions of supplement versus weekly additions of supplement and the difference between complete mix operation and fixed film operation. The test with NaOH indicated that prolonged use caused sodium toxicity in the reactor. Loadings up to 75% of design loading were obtained with daily additives of 15% municipal digester supernatant, while those obtained with daily addition of 15% digested swine manure exceeded design loadings. Loadings obtained with thermophilic temperatures approximately equaled those obtained with mesophilic temperatures. Some initial difficulty was experienced with full-scale start-up. The optimized anaerobic digestion and energy recovery facility has an estimated net annual energy recovery of 5,252 GJ. 27 refs., 16 figs., 8 tabs

  6. Evaluation of the rotary drum reactor process as pretreatment technology of municipal solid waste for thermophilic anaerobic digestion and biogas production.

    Science.gov (United States)

    Gikas, Petros; Zhu, Baoning; Batistatos, Nicolas Ion; Zhang, Ruihong

    2018-06-15

    Municipal solid waste (MSW) contains a large fraction of biodegradable organic materials. When disposed in landfills, these materials can cause adverse environmental impact due to gaseous emissions and leachate generation. This study was performed with an aim of effectively separating the biodegradable materials from a Mechanical Biological Treatment (MBT) facility and treating them in well-controlled anaerobic digesters for biogas production. The rotary drum reactor (RDR) process (a sub-process of the MBT facilities studied in the present work) was evaluated as an MSW pretreatment technology for separating and preparing the biodegradable materials in MSW to be used as feedstock for anaerobic digestion. The RDR processes used in six commercial MSW treatment plants located in the USA were surveyed and sampled. The samples of the biodegradable materials produced by the RDR process were analyzed for chemical and physical characteristics as well as anaerobically digested in the laboratory using batch reactors under thermophilic conditions. The moisture content, TS, VS and C/N of the samples varied between 64.7 and 44.4%, 55.6 to 35.3%, 27.0 to 41.3% and 24.5 to 42.7, respectively. The biogas yield was measured to be between 533.0 and 675.6 mL g -1 VS after 20 days of digestion. Approximately 90% of the biogas was produced during the first 13 days. The average methane content of the biogas was between 58.0 and 59.9%. The results indicated that the biodegradable materials separated from MSW using the RDR processes could be used as an excellent feedstock for anaerobic digestion. The digester residues may be further processed for compost production or further energy recovery by using thermal conversion processes such as combustion or gasification. Copyright © 2017. Published by Elsevier Ltd.

  7. Quantification of viable but nonculturable Salmonella spp. and Shigella spp. during sludge anaerobic digestion and their reactivation during cake storage.

    Science.gov (United States)

    Fu, B; Jiang, Q; Liu, H-B; Liu, H

    2015-10-01

    The presence of viable but nonculturable (VBNC) bacterial pathogens which often fail to be detected by cultivation and can regain the cultivability if the living conditions improve were reported. The objective of this study was to determine the occurrence of VBNC Salmonella spp. and Shigella spp. in the biosolids during anaerobic digestion and its reactivation during the cake storage. The occurrence of VBNC Salmonella spp. and Shigella spp. during mesophilic, temperature-phased, thermophilic anaerobic digestion of sewage sludge and the subsequent storage were studied by RT-qPCR and most probable number (MPN) method. The VBNC incidence of Salmonella spp. and Shigella spp. during thermophilic digestion was four orders of magnitude higher than those of mesophilic digestion. Accordingly, higher resuscitation ratio of VBNC pathogens was also achieved in thermophilic digested sludge. As a result, the culturable Salmonella typhimurium contents in thermophilic digested sludge after cake storage were two orders of magnitude higher than mesophilic digestion. Both quantitative PCR and reverse transcription quantitative PCR assay results showed the two bacterial counting numbers remained stable throughout the cake storage. The results indicate that the increase in the culturable Salmonella spp. and Shigella spp. after centrifugal dewatering was attributed to the resuscitation from the VBNC state to the culturable state. Thermophilic anaerobic digestion mainly induced Salmonella spp. and Shigella spp. into VBNC state rather than killed them, suggesting that the biological safety of sewage sludge by temperature-phased anaerobic digestion should be carefully assessed. © 2015 The Society for Applied Microbiology.

  8. Degradation of organic pollutants in sewage sludge by aerobic-thermophilic sludge treatment. Final report; Abbau organischer Schadstoffe im Klaerschlamm durch aerob-thermophile Schlammbehandlung. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Prechtl, S.

    1999-07-01

    A process for reduction of organic polllutants in sewage sludge was to be developed and optimized. The organic fraction of the solid matter in sewage sludge containes more than 300 different pollutant. Apart from the substances classified in the Sewage Sludge Ordinance (dioxins/furans, PCB), there are others that have been considered relevant as well but for which no sufficient data base is available. The research project investigated whether aerobic-thermophilic treatment (AT) would improve the sewage sludge quality with regard to phthalates (di(2-ethylhexyl)phthalate, DEHP), PAH and 4-nonylphenol (4-NP, a degradation product of nonionic tensides). Pollutants were analzyed by HPLC and GC/MS. The concentration of DEHP and 4-NP was reduced by 70% resp. 50% in laboratory experiments with doped sludges and by 61% resp. 53% in undoped sludges. In semi-industrial tests, a 14% reduction was achieved for DEHP and a 68% reduction for 4-NP. In the case of pyrene, the degradation was up to 57% in the laboratory experiments and 22% in semi-industrial tests. A combined process of short-term anaerobic digestion and AT resulted in a 60% reduction in the case of DEHP. Up to anthracene, PAH were reduced as well. In the case of higher-condensed PAH (basic load in the ppb range) there was no clear result. In the case of 4-NP, the degradation effect was counterbalanced by the formation of new 4-NP from alkylphenol ethoxylates in both anaerobic and aerobic conditions. The results prove the correlation between sewage sludge hygienisation and the time of residue in the reactor system. No enterobacteriaceae were found after a treatment of 96 h, both in the semi-industrial and the laboratory reactors. In activated sludge, a phenol-degrading mixed bacteria culture could be isolated which was also capable of degrading 4-NP in thermophilic conditions. [German] Das Ziel des Forschungsvorhabens war die Entwicklung/Optimierung eines Verfahrens zur Reduktion organischer Schadstoffe im

  9. Elucidation of the pathways of catabolic glutamate conversion in three thermophilic anaerobic bacteria.

    Science.gov (United States)

    Plugge, C M; van Leeuwen, J M; Hummelen, T; Balk, M; Stams, A J

    2001-07-01

    The glutamate catabolism of three thermophilic syntrophic anaerobes was compared based on the combined use of [(13)C] glutamate NMR measurements and enzyme activity determinations. In some cases the uptake of intermediates from different pathways was studied. The three organisms, Caloramator coolhaasii, Thermanaerovibrio acidaminovorans and strain TGO, had a different stoichiometry of glutamate conversion and were dependent on the presence of a hydrogen scavenger (Methanobacterium thermoautotrophicum Z245) to a different degree for their growth. C. coolhaasii formed acetate, CO(2), NH(4)(+) and H(2) from glutamate. Acetate was found to be formed through the beta-methylaspartate pathway in pure culture as well as in coculture. T. acidaminovorans converted glutamate to acetate, propionate, CO(2), NH(4)(+) and H(2). Most likely, this organism uses the beta-methylaspartate pathway for acetate formation. Propionate formation occurred through a direct oxidation of glutamate via succinyl-CoA and methylmalonyl-CoA. The metabolism of T. acidaminovorans shifted in favour of propionate formation when grown in coculture with the methanogen, but this did not lead to the use of a different glutamate degradation pathway. Strain TGO, an obligate syntrophic glutamate-degrading organism, formed propionate, traces of succinate, CO(2), NH(4)(+) and H(2). Glutamate was converted to propionate oxidatively via the intermediates succinyl-CoA and methylmalonyl-CoA. A minor part of the succinyl-CoA was converted to succinate and excreted.

  10. Temperature-phased anaerobic digestion of food waste: A comparison with single-stage digestions based on performance and energy balance.

    Science.gov (United States)

    Xiao, Benyi; Qin, Yu; Zhang, Wenzhe; Wu, Jing; Qiang, Hong; Liu, Junxin; Li, Yu-You

    2018-02-01

    The temperature-phased anaerobic digestion (TPAD) of food waste was studied for the purpose of comparing with single-stage mesophilic and thermophilic anaerobic digestion. The biogas and methane yields in the TPAD during the steady period were 0.759 ± 0.115 L/g added VS and 0.454 ± 0.201 L/g added VS, which were lower than those in the two single-stage anaerobic digestion. The improper sludge retention time may be the reason for the lower biogas and methane production in TPAD. The removal of volatile solids in the TPAD was 78.55 ± 4.59% and the lowest among the three anaerobic digestion processes. The reaction ratios of the four anaerobic digestion steps in the TPAD were all lower than those in the two single-stage anaerobic digestion. The energy conversion efficiency of the degraded substrate in the TPAD was similar with those in single-stage mesophilic and thermophilic anaerobic digestion systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. 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

    Biogas produced by anaerobic digestion, is mainly used in a gas motor for heat and electricity production. However, after removal of CO2, 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 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...

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

    DEFF Research Database (Denmark)

    Hubert, Casey; Arnosti, Carol; Brüchert, Volker

    2010-01-01

    Marine sediments harbour diverse populations of dormant thermophilic bacterial spores that become active in sediment incubation experiments at much higher than in situ temperature. This response was investigated in the presence of natural complex organic matter in sediments of two Arctic fjords......, as well as with the addition of freeze-dried Spirulina or individual high-molecular-weight polysaccharides. During 50°C incubation experiments, Arctic thermophiles catalysed extensive mineralization of the organic matter via extracellular enzymatic hydrolysis, fermentation and sulfate reduction. This high...... reactivity determined the extent of the thermophilic response. Fjord sediments with higher in situ SRR also supported higher SRR at 50°C. Amendment with Spirulina significantly increased volatile fatty acids production and SRR relative to unamended sediment in 50°C incubations. Spirulina amendment also...

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

    DEFF Research Database (Denmark)

    Chang, Tinghong; Yao, Shuo

    2011-01-01

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

  14. Thermodynamics and economic feasibility of acetone production from syngas using the thermophilic production host Moorella thermoacetica

    NARCIS (Netherlands)

    Redl, Stephanie; Sukumara, Sumesh; Ploeger, Tom; Wu, Liang; Ølshøj Jensen, Torbjørn; Nielsen, Alex Toftgaard; Noorman, H.J.

    2017-01-01

    Background: Syngas fermentation is a promising option for the production of biocommodities due to its abundance and compatibility with anaerobic fermentation. Using thermophilic production strains in a syngas fermentation process allows recovery of products with low boiling point from the off-gas

  15. Immobilization of anaerobic thermophilic bacteria for the production of cell-free thermostable. alpha. -amylases and pullulanases

    Energy Technology Data Exchange (ETDEWEB)

    Klingeberg, M [Goettingen Univ. (Germany, F.R.). Inst. fuer Mikrobiologie; Vorlop, K D [Technische Univ. Braunschweig (Germany, F.R.). Inst. fuer Technische Chemie; Antranikian, G [Technische Univ. Hamburg-Harburg, Hamburg (Germany, F. R.). Arbeitsbereich Biotechnologie 1

    1990-08-01

    For the production of cell-free thermostable {alpha}-amylases and pullulanases various anaerobic thermophilic bacteria that belong to the genera Clostridium and Thermoanaerobacter were immobilized in calcium alginate gel beads. The entrapment of bacteria was performed in full was well as in hollow spheres. An optimal limited medium, which avoided bacterial outgrowth, was developed for the cultivation of immobilized organisms at 60deg C using 0.4% starch as substrate. Compared to non-immobilized cells these techniques allowed a significant increase (up to 5.6-fold) in the specific activities of the extracellular enzymes formed. An increase in the productivity of extracellular enzymes was observed after immobilization of bacteria in full spheres. In the case of C. thermosaccharolyticum, for instance, the productivity was raised from 90 units (U)/10{sup 12} cells up to 700 U/10{sup 12} cells. Electrophoretic analysis of the secreted proteins showed that in all cases most of the amylolytic enzymes formed were released into the culture medium. Proteins that had a molecular mass of less than 450 000 daltons could easily diffuse through the gel matrix. Cultivation of immobilized bacteria in semi-continuous and fed-batch cultures was also accompanied by an elevation in the concentration of cell-free enzymes. (orig.).

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

    Science.gov (United States)

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

    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 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.

  17. Comparison of bacterial community structure and dynamics during the thermophilic composting of different types of solid wastes: anaerobic digestion residue, pig manure and chicken manure

    Science.gov (United States)

    Song, Caihong; Li, Mingxiao; Jia, Xuan; Wei, Zimin; Zhao, Yue; Xi, Beidou; Zhu, Chaowei; Liu, Dongming

    2014-01-01

    This study investigated the impact of composting substrate types on the bacterial community structure and dynamics during composting processes. To this end, pig manure (PM), chicken manure (CM), a mixture of PM and CM (PM + CM), and a mixture of PM, CM and anaerobic digestion residue (ADR) (PM + CM + ADR) were selected for thermophilic composting. The bacterial community structure and dynamics during the composting process were detected and analysed by polymerase chain reaction–denaturing gradient gel electrophoresis (DGGE) coupled with a statistic analysis. The physical-chemical analyses indicated that compared to single-material composting (PM, CM), co-composting (PM + CM, PM + CM + ADR) could promote the degradation of organic matter and strengthen the ability of conserving nitrogen. A DGGE profile and statistical analysis demonstrated that co-composting, especially PM + CM + ADR, could improve the bacterial community structure and functional diversity, even in the thermophilic stage. Therefore, co-composting could weaken the screening effect of high temperature on bacterial communities. Dominant sequencing analyses indicated a dramatic shift in the dominant bacterial communities from single-material composting to co-composting. Notably, compared with PM, PM + CM increased the quantity of xylan-degrading bacteria and reduced the quantity of human pathogens. PMID:24963997

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

    KAUST Repository

    Oosterkamp, Margreet J.; Mé ndez-Garcí a, Celia; Kim, Chang-H.; Bauer, Stefan; Ibá ñ ez, Ana B.; Zimmerman, Sabrina; Hong, Pei-Ying; Cann, Isaac K.; Mackie, Roderick I.

    2016-01-01

    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. Furthermore, we found that optimal conditions for biological treatment of thin stillage were similar for both mesophilic and thermophilic reactors. Bar-coded pyrosequencing of the 16S rRNA gene identified different microbial communities in mesophilic and thermophilic reactors and these differences in the microbial communities could be linked to the composition of the thin stillage.

  19. Continuous fermentative hydrogen production from cheese whey wastewater under thermophilic anaerobic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Azbar, Nuri; Cetinkaya Dokgoez, F. Tuba; Keskin, Tugba; Korkmaz, Kemal S.; Syed, Hamid M. [Bioengineering Department, Faculty of Engineering, Ege University, EBILTEM, Bornova, 35100 Izmir (Turkey)

    2009-09-15

    Hydrogen (H{sub 2}) production from cheese processing wastewater via dark anaerobic fermentation was conducted using mixed microbial communities under thermophilic conditions. The effects of varying hydraulic retention time (HRT: 1, 2 and 3.5 days) and especially high organic load rates (OLR: 21, 35 and 47 g chemical oxygen demand (COD)/l/day) on biohydrogen production in a continuous stirred tank reactor were investigated. The biogas contained 5-82% (45% on average) hydrogen and the hydrogen production rate ranged from 0.3 to 7.9 l H{sub 2}/l/day (2.5 l/l/day on average). H{sub 2} yields of 22, 15 and 5 mmol/g COD (at a constant influent COD of 40 g/l) were achieved at HRT values of 3.5, 2, and 1 days, respectively. On the other hand, H{sub 2} yields were monitored to be 3, 9 and 6 mmol/g COD, for OLR values of 47, 35 and 21 g COD/l/day, when HRT was kept constant at 1 day. The total measurable volatile fatty acid concentration in the effluent (as a function of influent COD) ranged between 118 and 27,012 mg/l, which was mainly composed of acetic acid, iso-butyric acid, butyric acid, propionic acid, formate and lactate. Ethanol and acetone production was also monitored from time to time. To characterize the microbial community in the bioreactor at different HRTs, DNA in mixed liquor samples was extracted immediately for PCR amplification of 16S RNA gene using eubacterial primers corresponding to 8F and 518R. The PCR product was cloned and subjected to DNA sequencing. The sequencing results were analyzed by using MegaBlast available on NCBI website which showed 99% identity to uncultured Thermoanaerobacteriaceae bacterium. (author)

  20. 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...

  1. Ability of industrial anaerobic ecosystems to produce methane from ethanol in psychrophilic, mesophilic and thermophilic conditions

    International Nuclear Information System (INIS)

    Mabala, Jojo Charlie

    2012-01-01

    The process of anaerobic degradation of organic matter is a natural phenomenon widespread in many ecosystems (eg, marshes, lakes, rice fields, digestive systems of animals and humans). A high microbial diversity is maintained during this process, reflecting a diversity of metabolic pathways involved. When complete, the anaerobic digestion results in the formation of biogas (mixture of methane and carbon dioxide). In terms of biotechnology, anaerobic treatment of organic pollution reduces the volume of waste and generates energy as methane recoverable in several forms (electricity, heat, natural gas, biofuels). Industrial digesters are mostly operated at 35 deg. C or 55 deg. C which requires exogenous energy. The objective of the thesis is to study the adaptability of ecosystems sourced from anaerobic industrial scale reactors treating different range of wastes from different processes to convert ethanol into biogas at various temperatures. The first phase of the study was to adapt, in laboratory reactors ecosystems to their original temperature with a readily biodegradable substrate (ethanol). Then, the performances of microbial communities (the maximum methanogenic potential and degradation kinetics) were estimated on a temperature gradient from 5 deg. C to 55 deg. C in batch reactors. The adaptation phase of the ecosystems in lab-scale reactors showed that the biogas averaged theoretical production and this production was followed by a decrease in reaction time with successive addition of the substrate. In addition, the kinetics of the biogas obtained varied greatly from one ecosystem to another. Molecular fingerprinting profiles (CE-SSCP) of bacterial and archaeal communities were performed at the beginning and at the end of conditioning. These community profiles were compared with each other by principal component analysis (PCA). Bacterial populations that ensured efficient performance were different from those that ensured a good adaptability. In addition, the

  2. Biokinetics and bacterial communities of propionate oxidizing bacteria in phased anaerobic sludge digestion systems.

    Science.gov (United States)

    Zamanzadeh, Mirzaman; Parker, Wayne J; Verastegui, Yris; Neufeld, Josh D

    2013-03-15

    Phased anaerobic digestion is a promising technology and may be a potential source of bio-energy production. Anaerobic digesters are widely used for sewage sludge stabilization and thus a better understanding of the microbial process and kinetics may allow increased volatile solids reduction and methane production through robust process operation. In this study, we analyzed the impact of phase separation and operational conditions on the bio-kinetic characteristics and communities of bacteria associated with four phased anaerobic digestion systems. In addition to significant differences between bacterial communities associated with different digester operating temperatures, our results also revealed that bacterial communities in the phased anaerobic digestion systems differed between the 1st and 2nd phase digesters and we identified strong community composition correlations with several measured physicochemical parameters. The maximum specific growth rates of propionate oxidizing bacteria (POB) in the mesophilic and thermophilic 1st phases were 11 and 23.7 mgCOD mgCOD(-1) d(-1), respectively, while those of the mesophilic and thermophilic 2nd-phase digesters were 6.7 and 18.6 mgCOD mgCOD(-1) d(-1), respectively. Hence, the biokinetic characteristics of the POB population were dependent on the digester loading. In addition, we observed that the temperature dependency factor (θ) values were higher for the less heavily loaded digesters as compared to the values obtained for the 1st-phase digesters. Our results suggested the appropriate application of two sets of POB bio-kinetic that reflect the differing growth responses as a function of propionate concentration (and/or organic loading rates). Also, modeling acetogenesis in phased anaerobic sludge digestion systems will be improved considering a population shift in separate phases. On the basis of the bio-kinetic values estimated in various digesters, high levels of propionate in the thermophilic digesters may be

  3. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Optimisation of the two-phase dry-thermophilic anaerobic digestion process of sulphate-containing municipal solid waste: population dynamics.

    Science.gov (United States)

    Zahedi, S; Sales, D; Romero, L I; Solera, R

    2013-11-01

    Microbial population dynamics and anaerobic digestion (AD) process to eight different hydraulic retention times (HRTs) (from 25d to 3.5d) in two-phase dry-thermophilic AD from sulphate-containing solid waste were investigated. Maximum values of gas production (1.9 ± 0.2 l H2/l/d; 5.4 ± 0.3 l CH4/l/d and 82 ± 9 ml H2S/l/d) and microbial activities were obtained at 4.5d HRT; where basically comprised hydrolysis step in the first phase (HRT=1.5d) and acidogenic step finished in the second phase as well as acetogenic-methanogenic steps (HRT=3d). In the first phase, hydrolytic-acidogenic bacteria (HABs) was the main group (44-77%) and Archaea, acetogens and sulphate-reducing bacteria (SRBs) contents were not significant; in the second phase (except to 2d HRT), microbial population was able to adapt to change in substrate and HRTs to ensure the proper functioning of the system and both acetogens and Archaea were dominated over SRBs. Decreasing HRT resulted in an increase in microbial activities. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. 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

  6. Thermophilic biofiltration of benzene and toluene.

    Science.gov (United States)

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

    2007-12-01

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

  7. 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 olive pulp; c) subsequent anaerobic treatment of the hydrogen-effluent with the simultaneous production of methane; and d) development of a mathematical model able to describe the anaerobic digestion of the olive pulp and the effluent of hydrogen producing process. Both continuous and batch experiments...

  8. Diversity, Localization, and Physiological Properties of Filamentous Microbes Belonging to Chloroflexi Subphylum I in Mesophilic and Thermophilic Methanogenic Sludge Granules

    Science.gov (United States)

    Yamada, Takeshi; Sekiguchi, Yuji; Imachi, Hiroyuki; Kamagata, Yoichi; Ohashi, Akiyoshi; Harada, Hideki

    2005-01-01

    We previously reported that the thermophilic filamentous anaerobe Anaerolinea thermophila, which is the first cultured representative of subphylum I of the bacterial phylum Chloroflexi, not only was one of the predominant constituents of thermophilic sludge granules but also was a causative agent of filamentous sludge bulking in a thermophilic (55°C) upflow anaerobic sludge blanket (UASB) reactor in which high-strength organic wastewater was treated (Y. Sekiguchi, H. Takahashi, Y. Kamagata, A. Ohashi, and H. Harada, Appl. Environ. Microbiol. 67:5740-5749, 2001). To further elucidate the ecology and function of Anaerolinea-type filamentous microbes in UASB sludge granules, we surveyed the diversity, distribution, and physiological properties of Chloroflexi subphylum I microbes residing in UASB granules. Five different types of mesophilic and thermophilic UASB sludge were used to analyze the Chloroflexi subphylum I populations. 16S rRNA gene cloning-based analyses using a 16S rRNA gene-targeted Chloroflexi-specific PCR primer set revealed that all clonal sequences were affiliated with the Chloroflexi subphylum I group and that a number of different phylotypes were present in each clone library, suggesting the ubiquity and vast genetic diversity of these populations in UASB sludge granules. Subsequent fluorescence in situ hybridization (FISH) of the three different types of mesophilic sludge granules using a Chloroflexi-specific probe suggested that all probe-reactive cells had a filamentous morphology and were widely distributed within the sludge granules. The FISH observations also indicated that the Chloroflexi subphylum I bacteria were not always the predominant populations within mesophilic sludge granules, in contrast to thermophilic sludge granules. We isolated two mesophilic strains and one thermophilic strain belonging to the Chloroflexi subphylum I group. The physiological properties of these isolates suggested that these populations may contribute to the

  9. Characterization of microbial biofilms in a thermophilic biogas system by high-throughput metagenome sequencing.

    Science.gov (United States)

    Rademacher, Antje; Zakrzewski, Martha; Schlüter, Andreas; Schönberg, Mandy; Szczepanowski, Rafael; Goesmann, Alexander; Pühler, Alfred; Klocke, Michael

    2012-03-01

    DNAs of two biofilms of a thermophilic two-phase leach-bed biogas reactor fed with rye silage and winter barley straw were sequenced by 454-pyrosequencing technology to assess the biofilm-based microbial community and their genetic potential for anaerobic digestion. The studied biofilms matured on the surface of the substrates in the hydrolysis reactor (HR) and on the packing in the anaerobic filter reactor (AF). The classification of metagenome reads showed Clostridium as most prevalent bacteria in the HR, indicating a predominant role for plant material digestion. Notably, insights into the genetic potential of plant-degrading bacteria were determined as well as further bacterial groups, which may assist Clostridium in carbohydrate degradation. Methanosarcina and Methanothermobacter were determined as most prevalent methanogenic archaea. In consequence, the biofilm-based methanogenesis in this system might be driven by the hydrogenotrophic pathway but also by the aceticlastic methanogenesis depending on metabolite concentrations such as the acetic acid concentration. Moreover, bacteria, which are capable of acetate oxidation in syntrophic interaction with methanogens, were also predicted. Finally, the metagenome analysis unveiled a large number of reads with unidentified microbial origin, indicating that the anaerobic degradation process may also be conducted by up to now unknown species. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

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

    International Nuclear Information System (INIS)

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

    2015-01-01

    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 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. 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.

  12. 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.

  13. Population dynamics during startup of thermophilic anaerobic digesters: the mixing factor.

    Science.gov (United States)

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

    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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Mesophilic and thermophilic anaerobic co-digestion of rendering plant and slaughterhouse wastes.

    Science.gov (United States)

    Bayr, Suvi; Rantanen, Marianne; Kaparaju, Prasad; Rintala, Jukka

    2012-01-01

    Co-digestion of rendering and slaughterhouse wastes was studied in laboratory scale semi-continuously fed continuously stirred tank reactors (CSTRs) at 35 and 55 °C. All in all, 10 different rendering plant and slaughterhouse waste fractions were characterised showing high contents of lipids and proteins, and methane potentials of 262-572 dm(3)CH(4)/kg volatile solids(VS)(added). In mesophilic CSTR methane yields of ca 720 dm(3) CH(4)/kg VS(fed) were obtained with organic loading rates (OLR) of 1.0 and 1.5 kg VS/m(3) d, and hydraulic retention time (HRT) of 50 d. For thermophilic process, the lowest studied OLR of 1.5 kg VS/m(3) d, turned to be unstable after operation of 1.5 HRT, due to accumulating ammonia, volatile fatty acids (VFAs) and probably also long chain fatty acids (LCFAs). In conclusion, mesophilic process was found to be more feasible for co-digestion than thermophilic process, methane yields being higher and process more stable in mesophilic conditions. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. 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.

  16. Role of Mn2+ and compatible solutes in the radiation resistance of thermophilic bacteria and archaea.

    Science.gov (United States)

    Webb, Kimberly M; DiRuggiero, Jocelyne

    2012-01-01

    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 Mn(2+)-dependent ROS scavenging in the aerobes. In contrast, the hyperthermophilic archaea Thermococcus gammatolerans and Pyrococcus furiosus did not contain significant amounts of intracellular Mn, and we found no significant antioxidant activity from mannosylglycerate and di-myo-inositol phosphate in vitro. We therefore propose that the low levels of IR-generated ROS under anaerobic conditions combined with highly constitutively expressed detoxification systems in these anaerobes are key to their radiation resistance and circumvent the need for the accumulation of Mn-antioxidant complexes in the cell.

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

    Science.gov (United States)

    Prevost, S; Andre, S; Remize, F

    2010-12-01

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

  18. Thermophilic Anaerobic Degradation of Butyrate by a Butyrate-Utilizing Bacterium in Coculture and Triculture with Methanogenic Bacteria

    OpenAIRE

    Ahring, Birgitte K.; Westermann, Peter

    1987-01-01

    We studied syntrophic butyrate degradation in thermophilic mixed cultures containing a butyrate-degrading bacterium isolated in coculture with Methanobacterium thermoautotrophicum or in triculture with M. thermoautotrophicum and the TAM organism, a thermophilic acetate-utilizing methanogenic bacterium. Butyrate was β-oxidized to acetate with protons as the electron acceptors. Acetate was used concurrently with its production in the triculture. We found a higher butyrate degradation rate in th...

  19. Thermophilic two-phase anaerobic digestion using an innovative fixed-bed reactor for enhanced organic matter removal and bioenergy recovery from sugarcane vinasse

    International Nuclear Information System (INIS)

    Fuess, Lucas Tadeu; Kiyuna, Luma Sayuri Mazine; Ferraz, Antônio Djalma Nunes; Persinoti, Gabriela Felix

    2017-01-01

    Highlights: • An innovative fixed-film anaerobic reactor was applied to sugarcane vinasse. • Stable operation was observed for OLRs as high as 30 kg COD m"−"3 day"−"1. • Propionate buildup did not impact the stability of the structured-bed reactor. • Enhanced bioenergy recovery was estimated from biodigestion with phase separation. • Energy extraction was over 20% higher compared to single-phase systems. - Abstract: This study considered the application of anaerobic digestion (AD) with phase separation combined with the use of an anaerobic structured-bed reactor (ASTBR) as the methanogenic phase for the treatment of sugarcane vinasse, a high-strength wastewater resulting from ethanol production. Two combined thermophilic acidogenic-methanogenic systems formed by one single acidogenic reactor followed by two methanogenic reactors operated in parallel were compared, namely, a conventional UASB reactor and an upflow ASTBR reactor. Increasing organic loading rate (OLR) conditions (15–30 kg COD m"−"3 d"−"1) were applied to the methanogenic reactors. The results highlighted the feasibility of applying the ASTBR to vinasse, indicating a global COD removal higher than 80%. The ASTBR exhibited a stable long-term operation (240 days), even for OLR values as high as 30 kg COD m"−"3 d"−"1. The application of similar conditions to the UASB reactor indicated severe performance losses, leading to the accumulation of acids for every increase in the OLR. An energetic potential of 181.5 MJ for each cubic meter of vinasse was estimated from both hydrogen and methane. The provision of bicarbonate alkalinity proved to be a key factor in obtaining stable performance, offsetting the limitations of relatively low hydraulic retention times (<24 h).

  20. Utilization of steam- and explosion-decompressed aspen wood by some anaerobes. [Acetivibrio cellulolyticus, Clostridium saccharolyticum, Zymomonas anaerobia

    Energy Technology Data Exchange (ETDEWEB)

    Khan, A W; Asther, M; Giuliano, C

    1984-01-01

    Tests made to study the suitability of using steam- and explosion-decompressed aspen wood as substrate in anaerobic fermentations indicated that after washing with dilute NaOH it becomes over 80% accessible to both mesophilic and thermophilic cellulolytic anaerobes and cellulases, compared with delignified, ball-milled pulp. After washing, this material was also found to be suitable for the single-step conversion of cellulose to ethanol using cocultures consisting of cellylolytic and ethanol-producing saccharolytic anaerobes; and without and after washing by the use of cellulolytic enzymes and ethanologenic anaerobes. 16 references, 3 tables.

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

    International Nuclear Information System (INIS)

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

    2014-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Benjamin M Zeldes

    2015-11-01

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

  3. 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

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

    NARCIS (Netherlands)

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

    2003-01-01

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

  5. 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.

  6. Taxonomy and functional roles of biogas microbiota binned from multiple metagenomes of anaerobic digestion systems

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Treu, Laura; Campanaro, Stefano

    Anaerobic digestion, a biologically mediated process, is a worldwide spread technology for biogas production. This work represents the first comprehensive catalogue of microbial genomes populating mesophilic and thermophilic biogas reactors treating manure, agro-industrial organic residues. High ...

  7. Defluviitalea phaphyphila sp. nov., a Novel Thermophilic Bacterium That Degrades Brown Algae.

    Science.gov (United States)

    Ji, Shi-Qi; Wang, Bing; Lu, Ming; Li, Fu-Li

    2016-02-01

    Brown algae are one of the largest groups of oceanic primary producers for CO2 removal and carbon sinks for coastal regions. However, the mechanism for brown alga assimilation remains largely unknown in thermophilic microorganisms. In this work, a thermophilic alginolytic community was enriched from coastal sediment, from which an obligate anaerobic and thermophilic bacterial strain, designated Alg1, was isolated. Alg1 shared a 16S rRNA gene identity of 94.6% with Defluviitalea saccharophila LIND6LT2(T). Phenotypic, chemotaxonomic, and phylogenetic studies suggested strain Alg1 represented a novel species of the genus Defluviitalea, for which the name Defluviitalea phaphyphila sp. nov. is proposed. Alg1 exhibited an intriguing ability to convert carbohydrates of brown algae, including alginate, laminarin, and mannitol, to ethanol and acetic acid. Three gene clusters participating in this process were predicted to be in the genome, and candidate enzymes were successfully expressed, purified, and characterized. Six alginate lyases were demonstrated to synergistically deconstruct alginate into unsaturated monosaccharide, followed by one uronic acid reductase and two 2-keto-3-deoxy-d-gluconate (KDG) kinases to produce pyruvate. A nonclassical mannitol 1-phosphate dehydrogenase, catalyzing D-mannitol 1-phosphate to fructose 1-phosphate in the presence of NAD(+), and one laminarase also were disclosed. This work revealed that a thermophilic brown alga-decomposing system containing numerous novel thermophilic alginate lyases and a unique mannitol 1-phosphate dehydrogenase was adopted by the natural ethanologenic strain Alg1 during the process of evolution in hostile habitats. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  8. Sugar Metabolism of the First Thermophilic Planctomycete Thermogutta terrifontis: Comparative Genomic and Transcriptomic Approaches

    Directory of Open Access Journals (Sweden)

    Alexander G. Elcheninov

    2017-11-01

    Full Text Available Xanthan gum, a complex polysaccharide comprising glucose, mannose and glucuronic acid residues, is involved in numerous biotechnological applications in cosmetics, agriculture, pharmaceuticals, food and petroleum industries. Additionally, its oligosaccharides were shown to possess antimicrobial, antioxidant, and few other properties. Yet, despite its extensive usage, little is known about xanthan gum degradation pathways and mechanisms. Thermogutta terrifontis, isolated from a sample of microbial mat developed in a terrestrial hot spring of Kunashir island (Far-East of Russia, was described as the first thermophilic representative of the Planctomycetes phylum. It grows well on xanthan gum either at aerobic or anaerobic conditions. Genomic analysis unraveled the pathways of oligo- and polysaccharides utilization, as well as the mechanisms of aerobic and anaerobic respiration. The combination of genomic and transcriptomic approaches suggested a novel xanthan gum degradation pathway which involves novel glycosidase(s of DUF1080 family, hydrolyzing xanthan gum backbone beta-glucosidic linkages and beta-mannosidases instead of xanthan lyases, catalyzing cleavage of terminal beta-mannosidic linkages. Surprisingly, the genes coding DUF1080 proteins were abundant in T. terrifontis and in many other Planctomycetes genomes, which, together with our observation that xanthan gum being a selective substrate for many planctomycetes, suggest crucial role of DUF1080 in xanthan gum degradation. Our findings shed light on the metabolism of the first thermophilic planctomycete, capable to degrade a number of polysaccharides, either aerobically or anaerobically, including the biotechnologically important bacterial polysaccharide xanthan gum.

  9. Sugar Metabolism of the First Thermophilic Planctomycete Thermogutta terrifontis: Comparative Genomic and Transcriptomic Approaches

    Science.gov (United States)

    Elcheninov, Alexander G.; Menzel, Peter; Gudbergsdottir, Soley R.; Slesarev, Alexei I.; Kadnikov, Vitaly V.; Krogh, Anders; Bonch-Osmolovskaya, Elizaveta A.; Peng, Xu; Kublanov, Ilya V.

    2017-01-01

    Xanthan gum, a complex polysaccharide comprising glucose, mannose and glucuronic acid residues, is involved in numerous biotechnological applications in cosmetics, agriculture, pharmaceuticals, food and petroleum industries. Additionally, its oligosaccharides were shown to possess antimicrobial, antioxidant, and few other properties. Yet, despite its extensive usage, little is known about xanthan gum degradation pathways and mechanisms. Thermogutta terrifontis, isolated from a sample of microbial mat developed in a terrestrial hot spring of Kunashir island (Far-East of Russia), was described as the first thermophilic representative of the Planctomycetes phylum. It grows well on xanthan gum either at aerobic or anaerobic conditions. Genomic analysis unraveled the pathways of oligo- and polysaccharides utilization, as well as the mechanisms of aerobic and anaerobic respiration. The combination of genomic and transcriptomic approaches suggested a novel xanthan gum degradation pathway which involves novel glycosidase(s) of DUF1080 family, hydrolyzing xanthan gum backbone beta-glucosidic linkages and beta-mannosidases instead of xanthan lyases, catalyzing cleavage of terminal beta-mannosidic linkages. Surprisingly, the genes coding DUF1080 proteins were abundant in T. terrifontis and in many other Planctomycetes genomes, which, together with our observation that xanthan gum being a selective substrate for many planctomycetes, suggest crucial role of DUF1080 in xanthan gum degradation. Our findings shed light on the metabolism of the first thermophilic planctomycete, capable to degrade a number of polysaccharides, either aerobically or anaerobically, including the biotechnologically important bacterial polysaccharide xanthan gum. PMID:29163426

  10. 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

  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. 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). Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Stable thermophilic anaerobic digestion of dissolved air flotation (DAF) sludge by co-digestion with swine manure.

    Science.gov (United States)

    Creamer, K S; Chen, Y; Williams, C M; Cheng, J J

    2010-05-01

    Environmentally sound treatment of by-products in a value-adding process is an ongoing challenge in animal agriculture. The sludge produced as a result of the dissolved air flotation (DAF) wastewater treatment process in swine processing facilities is one such low-value residue. The objective of this study was to determine the fundamental performance parameters for thermophilic anaerobic digestion of DAF sludge. Testing in a semi-continuous stirred tank reactor and in batch reactors was conducted to determine the kinetics of degradation and biogas yield. Stable operation could not be achieved using pure DAF sludge as a substrate, possibly due to inhibition by long-chain fatty acids or to nutrient deficiencies. However, in a 1:1 ratio (w/w, dry basis) with swine manure, operation was both stable and productive. In the semi-continuous stirred reactor at 54.5 degrees Celsius, a hydraulic residence time of 10 days, and an organic loading rate of 4.68 gVS/day/L, the methane production rate was 2.19 L/L/day and the specific methane production rate was 0.47 L/gVS (fed). Maximum specific methanogenic activity (SMA) in batch testing was 0.15 mmoles CH(4) h(-1) gVS(-1) at a substrate concentration of 6.9 gVS L(-1). Higher substrate concentrations cause an initial lag in methane production, possibly due to long-chain fatty acid or nitrogen inhibition. Copyright 2009 Elsevier Ltd. All rights reserved.

  14. 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

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

    Science.gov (United States)

    Oosterkamp, Margreet J; Méndez-García, Celia; Kim, Chang-H; Bauer, Stefan; Ibáñez, Ana B; Zimmerman, Sabrina; Hong, Pei-Ying; Cann, Isaac K; Mackie, Roderick I

    2016-01-01

    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. 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. 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. Furthermore, we found

  16. 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)

  17. 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.

  18. Anaerobic solid state fermentation of cellulosic substrates with possible application to cellulase production

    Energy Technology Data Exchange (ETDEWEB)

    Vandevoorde, L; Verstraete, W

    1987-08-01

    A solid state fermentation process was developed for the conversion of straw and cellulose under anaerobic conditions by a mixed culture of cellulolytic and methanogenic organisms. The bioconversion rate and efficiency were compared under mesophilic (35/sup 0/C) and thermophilic (55/sup 0/C) conditions. Cellulolytic activity was assayed in terms of sugar and overall soluble organic matter (chemical oxygen demand, COD) production. Maximum conversion rates were obtained under thermophilic conditions, i.e. 8.4 g and 14.2 g COD/kg.d, respectively, when wheat straw and cellulose were used as substrates. The cellulolytic activity of the reactor contents (23% dry matter), measured under substrate excess conditions, amounted to 50 g COD/kg.d. As a comparison, the activity of rumen contents (15 % dry matter) measured by the same assay amounted to 150 g COD/kg . d. The anaerobic cellulases appeared to be substrate bound. This and the relative low activity levels attained, limit the perspectives of producing cellulase enzymes by this type of process.

  19. Thermophilic composting of municipal solid waste

    International Nuclear Information System (INIS)

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

    2009-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-10-15

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

  1. Evaluation of pretreatment methods on mixed inoculum for both batch and continuous thermophilic biohydrogen production from cassava stillage.

    Science.gov (United States)

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

    2010-02-01

    Anaerobic sludges, pretreated by chloroform, base, acid, heat and loading-shock, as well as untreated sludge were evaluated for their thermophilic fermentative hydrogen-producing characters from cassava stillage in both batch and continuous experiments. Results showed that the highest hydrogen production was obtained by untreated sludge and there were significant differences (pstillage.

  2. Effect of silver nanoparticles and antibiotics on antibiotic resistance genes in anaerobic digestion.

    Science.gov (United States)

    Miller, Jennifer H; Novak, John T; Knocke, William R; Young, Katherine; Hong, Yanjuan; Vikesland, Peter J; Hull, Matthew S; Pruden, Amy

    2013-05-01

    Water resource recovery facilities have been described as creating breeding ground conditions for the selection, transfer, and dissemination of antibiotic resistance genes (ARGs) among various bacteria. The objective of this study was to determine the effect of direct addition of antibiotic and silver nanoparticles (Ag NPs, or nanosilver) on the occurrence of ARGs in thermophilic anaerobic digesters. Test thermophilic digesters were amended with environmentally-relevant concentrations of Ag NP (0.01, 0.1, and 1.0 mg-Ag/L; corresponding to approximately 0.7, 7.0, and 70 mg-Ag/kg total solids) and sulfamethoxazole (SMX) that span susceptible to resistant classifications (1, 5, and 50 mg/L) as potential selection pressures for ARGs. Tetracycline (tet(O), tet(W)) and sulfonamide (sulI, sulII) ARGs and the integrase enzyme gene (intI1) associated with Class 1 integrons were measured in raw sludge, test thermophilic digesters, a control thermophilic digester, and a control mesophilic digester. There was no apparent effect of Ag NPs on thermophilic anaerobic digester performance. The maximum SMX addition (50 mg/L) resulted in accumulation of volatile fatty acids and low pH, alkalinity, and volatile solids reduction. There was no significant difference between ARG gene copy numbers (absolute or normalized to 16S rRNA genes) in amended thermophilic digesters and the control thermophilic digester. Antibiotic resistance gene copy numbers in digested sludge ranged from 10(3) to 10(6) copies per microL (approximately 8 x10(1) to 8 x 10(4) copies per microg) of sludge as result of a 1-log reduction of ARGs (2-log reduction for intI1). Quantities of the five ARGs in raw sludge ranged from 10(4) to 10(8) copies per microL (approximately 4 x 10(2) to 4 x 10(6) per microg) of sludge. Test and control thermophilic digesters (53 degrees C, 12-day solids retention time [SRT]) consistently reduced but did not eliminate levels of all analyzed genes. The mesophilic digester (37 degrees C

  3. Optimisation of single-phase dry-thermophilic anaerobic digestion under high organic loading rates of industrial municipal solid waste: population dynamics.

    Science.gov (United States)

    Zahedi, S; Sales, D; Romero, L I; Solera, R

    2013-10-01

    Different high feed organic loading rates (OLRs) (from 5.7 g to 46.0 g TVS/l/d) or hydraulic retention times (HRTs) (from 15 d to 2 d) in single-phase dry-thermophilic anaerobic digestion (AD) of organic fraction municipal solid waste (OFMSW) were investigated. The specific gas production (SGP) values (0.25-0.53 m(3)/kg TVS) and the percentages of Eubacteria, Archaea, H2-utilising methanogens (HUMs) and acetate-utilising methanogens (AUMs) were stable within the ranges 80.2-91.1%, 12.4-18.5%, 4.4-9.8% and 5.5-10.9%, respectively. A HUM/AUM ratio greater than 0.7 seems to be necessary to maintain very low partial pressures of H2 required for dry AD process. Increasing OLR resulted in an increase in all the populations, except for propionate-utilising acetogens (PUAs). Optimal conditions were obtained at 3d HRT (OLR=30.7 g TVS/l/d), which is lower than the doubling time of acetogens and methanogens. The methane production (MP) was clearly higher than those reported in AD of OFMSW. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. 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......-VS/(m3•d) a methane yield of 340 L/kg-VS was achieved for thermophilic operation while 270 L/kg-VS was obtained under mesophilic conditions. Thermophilic operation was, however, less robust towards further increase of the loading rate and for loading rates higher than 5 kg-VS/(m3•d) the yield was higher...... 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...

  5. Evaluation of anaerobic digestion processes for short sludge-age waste activated sludge combined with anammox treatment of digestate liquor.

    Science.gov (United States)

    Ge, Huoqing; Batstone, Damien; Keller, Jurg

    2016-01-01

    The need to reduce energy input and enhance energy recovery from wastewater is driving renewed interest in high-rate activated sludge treatment (i.e. short hydraulic and solids retention times (HRT and SRT, respectively)). This process generates short SRT activated sludge stream, which should be highly degradable. However, the evaluation of anaerobic digestion of short SRT sludge has been limited. This paper assesses anaerobic digestion of short SRT sludge digestion derived from meat processing wastewater under thermophilic and mesophilic conditions. The thermophilic digestion system (55°C) achieved 60 and 68% volatile solids destruction at 8 day and 10 day HRT, respectively, compared with 50% in the mesophilic digestion system (35°C, 10 day HRT). The digestion effluents from the thermophilic (8-10 day HRT) and mesophilic systems were stable, as assessed by residual methane potentials. The ammonia rich sludge dewatering liquor was effectively treated by a batch anammox process, which exhibited comparable nitrogen removal rate as the tests using a control synthetic ammonia solution, indicating that the dewatering liquor did not have inhibiting/toxic effects on the anammox activity.

  6. Influence of two-phase anaerobic digestion on fate of selected antibiotic resistance genes and class I integrons in municipal wastewater sludge

    DEFF Research Database (Denmark)

    Wu, Ying; Cui, Erping; Zuo, Yiru

    2016-01-01

    The response of representative antibiotic resistance genes (ARGs) to lab-scale two-phase (acidogenic/methanogenic phase) anaerobic digestion processes under thermophilic and mesophilic conditions was explored. The associated microbial communities and bacterial pathogens were characterized by 16S ...... for ermB and blaTEM. ARGs patterns were correlated with Proteobacteria and Actinobacteria during the two-phase anaerobic digestion....

  7. Thermophilic co-digestion feasibility of distillers grains and swine manure: effect of C/N ratio and organic loading rate during high solid anaerobic digestion (HSAD).

    Science.gov (United States)

    Sensai, P; Thangamani, A; Visvanathan, C

    2014-01-01

    Anaerobic co-digestion of high solids containing distillers grains and swine manure (total solids, 27 +/- 2% and 18 +/- 2%, respectively) was evaluated in this study to assess the effect of C/N ratio and organic loading rate (OLR). Feed mixture was balanced to achieve a C/N ratio of 30/1 by mixing distillers grains and swine manure. Pilot-scale co-digestion of distillers grains and swine manure was carried out under thermophilic conditions in the continuous mode for seven different OLRs from R1 to R7 (3.5, 5, 6, 8, 10, 12 and 14 kg VS/m3 day) under high solid anaerobic digestion. The methane yield and volatile solid (VS) removal were consistent; ranging from 0.33 to 0.34 m3CH4/kg VS day and 50-53%, respectively, until OLR 8 kg VS/m3 day. After which methane yield and VS removal significantly decreased to 0.26 m3 CH4/kg VS day and 42%, respectively, when OLR was increased to 14 kg VS/m3 day. However, during operation, at OLR of 10 kg VS/m3 day, the methane yield and VS removal increased after the 19th day to 0.33 m3 CH4/kg VS day and 46%, respectively, indicating that a longer acclimatization period is required by methanogens at a higher loading rate.

  8. Thermophilic and alkalophilic xylanases from several Dictyoglomus isolates

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-10-01

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

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

    NARCIS (Netherlands)

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

    2012-01-01

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

  10. Brockia lithotrophica gen. nov., sp. nov., an anaerobic thermophilic bacterium from a terrestrial hot spring.

    Science.gov (United States)

    Perevalova, Anna A; Kublanov, Ilya V; Baslerov, R V; Zhang, Gengxin; Bonch-Osmolovskaya, Elizaveta A

    2013-02-01

    A novel thermophilic bacterium, strain Kam1851(T), was isolated from a terrestrial hot spring of the Uzon Caldera, Kamchatka Peninsula, Russia. Cells of strain Kam1851(T) were spore-forming rods with a gram-positive type of cell wall. Growth was observed between 46 and 78 °C, and pH 5.5-8.5. The optimal growth (doubling time, 6.0 h) was at 60-65 °C and pH 6.5. The isolate was an obligate anaerobe growing in pre-reduced medium only. It grew on mineral medium with molecular hydrogen or formate as electron donors, and elemental sulfur, thiosulfate or polysulfide as electron acceptors. The main cellular fatty acids were C(16 : 0) (34.2 %), iso-C(16 : 0) (18 %), C(18 : 0) (12.8 %) and iso-C(17 : 0) (11.1 %). The G+C content of the genomic DNA of strain Kam1851(T) was 63 mol%. 16S rRNA gene sequence analysis showed that strain Kam1851(T) belonged to the order Thermoanaerobacterales, but it was not closely related to representatives of any genera with validly published names. The most closely related strains, which had no more than 89.2 % sequence similarity, were members of the genera Ammonifex and Caldanaerobacter. On the basis of its phylogenetic position and novel phenotypic features, isolate Kam1851(T) is proposed to represent a novel species in a new genus, Brockia lithotrophica gen. nov., sp. nov.; the type strain of Brockia lithotrophica is Kam1851(T) ( = DSM 22653(T) = VKM B-2685(T)).

  11. 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

  12. Correlation between system performance and bacterial composition under varied mixing intensity in thermophilic anaerobic digestion of food waste

    KAUST Repository

    Ghanimeh, Sophia A.; Al-Sanioura, Dana N.; Saikaly, Pascal; El-Fadel, Mutasem

    2017-01-01

    This study examines the stability and efficiency of thermophilic anaerobic digesters treating food waste under various mixing velocities (50–160 rpm). The results showed that high velocities (120 and 160 rpm) were harmful to the digestion process with 18–30% reduction in methane generation and 1.8 to 3.8 times increase in volatile fatty acids (VFA) concentrations, compared to mild mixing (50 and 80 rpm). Also, the removal rate of soluble COD dropped from 75 to 85% (at 50–80 rpm) to 20–59% (at 120–160 rpm). Similarly, interrupted mixing caused adverse impacts and led to near-failure conditions with excessive VFA accumulation (15.6 g l), negative removal rate of soluble COD and low methane generation (132 ml gVS). The best efficiency and stability were achieved under mild mixing (50 and 80 rpm). In particular, the 50 rpm stirring speed resulted in the highest methane generation (573 ml gVS). High-throughput sequencing of 16S rRNA genes revealed that the digesters were dominated by one bacterial genus (Petrotoga; phylym Thermotogae) at all mixing velocities except at 0 rpm, where the community was dominated by one bacterial genus (Anaerobaculum; phylum Synergistetes). The Petrotoga genus seems to have played a major role in the degradation of organic matter.

  13. Correlation between system performance and bacterial composition under varied mixing intensity in thermophilic anaerobic digestion of food waste

    KAUST Repository

    Ghanimeh, Sophia A.

    2017-12-07

    This study examines the stability and efficiency of thermophilic anaerobic digesters treating food waste under various mixing velocities (50–160 rpm). The results showed that high velocities (120 and 160 rpm) were harmful to the digestion process with 18–30% reduction in methane generation and 1.8 to 3.8 times increase in volatile fatty acids (VFA) concentrations, compared to mild mixing (50 and 80 rpm). Also, the removal rate of soluble COD dropped from 75 to 85% (at 50–80 rpm) to 20–59% (at 120–160 rpm). Similarly, interrupted mixing caused adverse impacts and led to near-failure conditions with excessive VFA accumulation (15.6 g l), negative removal rate of soluble COD and low methane generation (132 ml gVS). The best efficiency and stability were achieved under mild mixing (50 and 80 rpm). In particular, the 50 rpm stirring speed resulted in the highest methane generation (573 ml gVS). High-throughput sequencing of 16S rRNA genes revealed that the digesters were dominated by one bacterial genus (Petrotoga; phylym Thermotogae) at all mixing velocities except at 0 rpm, where the community was dominated by one bacterial genus (Anaerobaculum; phylum Synergistetes). The Petrotoga genus seems to have played a major role in the degradation of organic matter.

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2010-02-01

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

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

    Science.gov (United States)

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

    2010-01-01

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

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

    NARCIS (Netherlands)

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

    2018-01-01

    Fermentation and anaerobic digestion of organic waste and wastewater is broadly studied and applied. Despite widely available results and data for these processes, comparison of the generated results in literature is difficult. Not only due to the used variety of process conditions, but also

  18. 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).

  19. Dissimilatory oxidation and reduction of elemental sulfur in thermophilic archaea.

    Science.gov (United States)

    Kletzin, Arnulf; Urich, Tim; Müller, Fabian; Bandeiras, Tiago M; Gomes, Cláudio M

    2004-02-01

    The oxidation and reduction of elemental sulfur and reduced inorganic sulfur species are some of the most important energy-yielding reactions for microorganisms living in volcanic hot springs, solfataras, and submarine hydrothermal vents, including both heterotrophic, mixotrophic, and chemolithoautotrophic, carbon dioxide-fixing species. Elemental sulfur is the electron donor in aerobic archaea like Acidianus and Sulfolobus. It is oxidized via sulfite and thiosulfate in a pathway involving both soluble and membrane-bound enzymes. This pathway was recently found to be coupled to the aerobic respiratory chain, eliciting a link between sulfur oxidation and oxygen reduction at the level of the respiratory heme copper oxidase. In contrast, elemental sulfur is the electron acceptor in a short electron transport chain consisting of a membrane-bound hydrogenase and a sulfur reductase in (facultatively) anaerobic chemolithotrophic archaea Acidianus and Pyrodictium species. It is also the electron acceptor in organoheterotrophic anaerobic species like Pyrococcus and Thermococcus, however, an electron transport chain has not been described as yet. The current knowledge on the composition and properties of the aerobic and anaerobic pathways of dissimilatory elemental sulfur metabolism in thermophilic archaea is summarized in this contribution.

  20. Biological hydrogen production from biomass by thermophilic bacteria

    International Nuclear Information System (INIS)

    Claassen, P.A.M.; Mars, A.E.; Budde, M.A.W.; Lai, M.; de Vrije, T.; van Niel, E.W.J.

    2006-01-01

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

  1. Microbial population dynamics during startup of a full-scale anaerobic digester treating industrial food waste in Kyoto eco-energy project.

    Science.gov (United States)

    Ike, Michihiko; Inoue, Daisuke; Miyano, Tomoki; Liu, Tong Tong; Sei, Kazunari; Soda, Satoshi; Kadoshin, Shiro

    2010-06-01

    The microbial community in a full-scale anaerobic digester (2300m3) treating industrial food waste in the Kyoto Eco-Energy Project was analyzed using terminal restriction fragment length polymorphism for eubacterial and archaeal 16S rRNA genes. Both thermophilic and mesophilic sludge of treated swine waste were seeded to the digestion tank. During the 150-day startup period, coffee grounds as a main food waste, along with potato, kelp and boiled beans, tofu, bean curd lees, and deep-fried bean curd were fed to the digestion process step-by-step (max. 40t/d). Finally, the methane yield reached 360m3/t-feed with 40days' retention time, although temporary accumulation of propionate was observed. Eubacterial communities that formed in the thermophilic digestion tank differed greatly from both thermophilic and mesophilic types of seed sludge. Results suggest that the Actinomyces/Thermomonospora and Ralstonia/Shewanella were contributors for hydrolyzation and degradation of food waste into volatile fatty acids. Acetate-utilizing methanogens, Methanosaeta, were dominant in seed sludges of both types, but they decreased drastically during processing in the digestion tank. Methanosarcina and Methanobrevibacter/Methanobacterium were, respectively, possible main contributors for methane production from acetate and H2 plus CO2. Copyright 2010 Elsevier Ltd. All rights reserved.

  2. 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

  3. Influence of two-phase anaerobic digestion on fate of selected antibiotic resistance genes and class I integrons in municipal wastewater sludge.

    Science.gov (United States)

    Wu, Ying; Cui, Erping; Zuo, Yiru; Cheng, Weixiao; Rensing, Christopher; Chen, Hong

    2016-07-01

    The response of representative antibiotic resistance genes (ARGs) to lab-scale two-phase (acidogenic/methanogenic phase) anaerobic digestion processes under thermophilic and mesophilic conditions was explored. The associated microbial communities and bacterial pathogens were characterized by 16S rRNA gene sequencing. A two-phase thermophilic digestion reduced the presence of tetA, tetG, tetX, sul1, ermB, dfrA1, dfrA12 and intI1 exhibiting 0.1-0.72 log unit removal; in contrast, tetO, tetW, sul3, ermF and blaTEM even increased relative to the feed, and sul2 showed no significant decrease. The acidogenic phase of thermophilic digestion was primarily responsible for reducing the quantity of these genes, while the subsequent methanogenic phase caused a rebound in their quantity. In contrast, a two-phase mesophilic digestion process did not result in reducing the quantity of all ARGs and intI1 except for ermB and blaTEM. ARGs patterns were correlated with Proteobacteria and Actinobacteria during the two-phase anaerobic digestion. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Physiology of thermophilic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Ljungdahl, L G

    1979-01-01

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

  5. Long-term stability of thermophilic co-digestion submerged anaerobic membrane reactor encountering high organic loading rate, persistent propionate and detectable hydrogen in biogas.

    Science.gov (United States)

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

    2013-12-01

    The performance of thermophilic anaerobic co-digestion of coffee grounds and sludge using membrane reactor was investigated for 148 days, out of a total research duration of 263 days. The OLR was increased from 2.2 to 33.7 kg-COD/m(3)d and HRT was shortened from 70 to 7 days. A significant irreversible drop in pH confirmed the overload of reactor. Under a moderately high OLR of 23.6 kg-COD/m(3)d, and with HRT and influent total solids of 10 days and 150 g/L, respectively, the COD removal efficiency was 44.5%. Hydrogen in biogas was around 100-200 ppm, which resulted in the persistent propionate of 1.0-3.2g/L. The VFA consumed approximately 60% of the total alkalinity. NH4HCO3 was supplemented to maintain alkalinity. The stability of system relied on pH management under steady state. The 16SrDNA results showed that hydrogen-utilizing methanogens dominates the archaeal community. The propionate-oxidizing bacteria in bacterial community was insufficient. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Development of an efficient anaerobic co-digestion process for garbage, excreta, and septic tank sludge to create a resource recycling-oriented society.

    Science.gov (United States)

    Sun, Zhao-Yong; Liu, Kai; Tan, Li; Tang, Yue-Qin; Kida, Kenji

    2017-03-01

    In order to develop a resource recycling-oriented society, an efficient anaerobic co-digestion process for garbage, excreta and septic tank sludge was studied based on the quantity of each biomass waste type discharged in Ooki machi, Japan. The anaerobic digestion characteristics of garbage, excreta and 5-fold condensed septic tank sludge (hereafter called condensed sludge) were determined separately. In single-stage mesophilic digestion, the excreta with lower C/N ratios yielded lower biogas volumes and accumulated higher volumes of volatile fatty acid (VFA). On the other hand, garbage allowed for a significantly larger volatile total solid (VTS) digestion efficiency as well as biogas yield by thermophilic digestion. Thus, a two-stage anaerobic co-digestion process consisting of thermophilic liquefaction and mesophilic digestion phases was proposed. In the thermophilic liquefaction of mixed condensed sludge and household garbage (wet mass ratio of 2.2:1), a maximum VTS loading rate of 24g/L/d was achieved. In the mesophilic digestion of mixed liquefied material and excreta (wet mass ratio of 1:1), biogas yield reached approximately 570ml/g-VTS fed with a methane content of 55% at a VTS loading rate of 1.0g/L/d. The performance of the two-stage process was evaluated by comparing it with a single-stage process in which biomass wastes were treated separately. Biogas production by the two-stage process was found to increase by approximately 22.9%. These results demonstrate the effectiveness of a two-stage anaerobic co-digestion process in enhancement of biogas production. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. 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...

  8. Carboxydobrachium pacificum gen. nov., sp. nov., a new anaerobic, thermophilic, CO-utilizing marine bacterium from Okinawa Trough.

    Science.gov (United States)

    Sokolova, T G; González, J M; Kostrikina, N A; Chernyh, N A; Tourova, T P; Kato, C; Bonch-Osmolovskaya, E A; Robb, F T

    2001-01-01

    A new anaerobic, thermophilic, CO-utilizing marine bacterium, strain JMT, was isolated from a submarine hot vent in Okinawa Trough. Cells of strain JMT were non-motile thin straight rods, sometimes branching, with a cell wall of the Gram-positive type, surrounded with an S-layer. Chains of three to five cells were often observed. The isolate grew chemolithotrophically on CO, producing equimolar quantities of H2 and CO2 (according to the equation CO+H2O-->CO2+H2) and organotrophically on peptone, yeast extract, starch, cellobiose, glucose, galactose, fructose and pyruvate, producing H2, acetate and CO2. Growth was observed from 50 to 80 degrees C with an optimum at 70 degrees C. The optimum pH was 6.8-7.1. The optimum concentration of sea salts in the medium was 20.5-25.5 g l(-1). The generation time under optimal conditions was 7.1 h. The DNA G+C content was 33 mol %. Growth of isolate JMT was not inhibited by penicillin, but ampicillin, streptomycin, kanamycin and neomycin completely inhibited growth. The results of 16S rDNA sequence analysis revealed that strain JMT belongs to the Thermoanaerobacter phylogenetic group within the Bacillus-Clostridium subphylum of Gram-positive bacteria but represents a separate branch of this group. On the basis of morphological and physiological features and phylogenetic data, this isolate should be assigned to a new genus, for which the name Carboxydobrachium is proposed. The type species is Carboxydobrachium pacificum; the type strain is JMT (= DSM 12653T).

  9. Properties of thermophilic microorganisms

    International Nuclear Information System (INIS)

    Ljungdahl, L.G.

    1984-01-01

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

  10. 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)

  11. Biogas final digestive byproduct applied to croplands as fertilizer contains high levels of steroid hormones

    International Nuclear Information System (INIS)

    Rodriguez-Navas, Carlos; Björklund, Erland; Halling-Sørensen, Bent; Hansen, Martin

    2013-01-01

    In this study we evaluate and demonstrate the occurrence of nine natural and one synthetic steroid hormone, including estrogens, androgens and progestagens in biogas final digestate byproduct (digestion liquid) commonly used as an agricultural fertilizer. We investigated two biogas sites that utilize different anaerobic digestion technologies (mesophilic and thermophilic) from swine manure and other organic wastes. Individual hormone concentration levels were observed up to 1478 ng g −1 dry weight or 22.5 mg kg −1 N with estrone and progesterone reaching highest concentration levels. Evaluation of the potential environmental burden through the application in agriculture was also assessed on the basis of predicted environmental concentrations. This study indicates that the biogas digestion process does not completely remove steroid hormones from livestock manure and use of final digestate byproduct on croplands contributes to the environmental emission of hormones. -- Eight steroid hormones were found in biogas digestate byproduct in the ng g −1 dm levels. Anaerobic digestion processes do not completely remove steroid hormones from organic waste residues

  12. Application of the thermostable β-galactosidase, BgaB, from Geobacillus stearothermophilus as a versatile reporter under anaerobic and aerobic conditions

    DEFF Research Database (Denmark)

    Jensen, Torbjørn Ølshøj; Pogrebnyakov, Ivan; Falkenberg, Kristoffer Bach

    2017-01-01

    Use of thermophilic organisms has a range of advantages, but the significant lack of engineering tools limits their applications. Here we show that β-galactosidase from Geobacillus stearothermophilus (BgaB) can be applicable in a range of conditions, including different temperatures and oxygen...... and encompassed fivefold variation. The experimental pipeline allowed construction and measurement of expression levels of the library in just 4 days. This β-galactosidase provides a promising tool for engineering of aerobic, anaerobic, and thermophilic production organisms such as Geobacillus species....

  13. Optimization of the purification process of wine lees through anaerobic filter reactors. Optimizacion del proceso de depuracion de vinazas de vino mediante reactores tipo filtro anaerobio

    Energy Technology Data Exchange (ETDEWEB)

    Nebot Sanz, E.; Romero Garcia, L.I.; Quiroga Alonso, J.M.; Sales Marquez, D. (Departamento de Ingenieria Quimica, Universidad de Cadiz, Cadiz (Spain))

    1994-01-01

    In this work, the optimization of thermophilic anaerobic process, using Anaerobic Filter technology was studied. Feed of the Anaerobic Filter was wine-distillery wastewaters. The experiments developed were carried out at lab-scale downflow anaerobic filter reactors. Reactors were filled with a high porous plastic media (Flocor-R). The media support entities have a high surface/volume ratio. Test were run to determine the maximum organic load attainable in the system for wich both, the depurative efficiency and the methane production were optimum. Likewise, the effect of organic load on the anaerobic filter performance were studied. (Author) 15 refs. (Author)

  14. Hexavalent uranium reduction from solid phase by thermophilic bacterium Thermoterrabacterium ferrireducens

    International Nuclear Information System (INIS)

    Khijniak, T.V.; Slobodkin, A.I.; Bonch-Osmolovskaya, E.A.; Medvedeva-Lyalikova, N.N.; Coker, V.; Lloyd, J.R.; Birkeland, N.K.

    2005-01-01

    Full text of publication follows: It has been reported that in uranium-contaminated sites, solid-phase U(VI) present in sediments is resistant to microbial reduction. Also, it was demonstrated that mesophilic iron and sulfate-reducing bacteria can reduce hexavalent uranium and sulphate-reducing bacteria were able to grow via uranium reduction. Among thermophilic microorganisms reduction of hexavalent uranium has been demonstrated only for cell suspensions of two genera: Pyrobaculum and Thermus. In the present study, Thermoterrabacterium ferrireducens was tested for reduction of U(VI), a thermophilic, gram-positive anaerobic bacterium capable for growth with the reduction of various electron acceptors including Fe(III). Kinetic of bacterial growth, uranium reduction and influence of different uranium concentrations were investigated at 65 deg. C. Due to presence of phosphate in the basal medium yellow uranium phosphate precipitate was formed after addition of uranyl acetate. After 68 h of incubation control tubes without bacteria were contained yellow precipitate whereas in presence of bacteria precipitate turned to the grey color. In the control tubes uranium phosphates and other elements formed a uniform mixture of crystals, but in presence of bacteria the round shape particles, containing uranium, were found by Environmental Scan Electron Microscopy of air-dried or frozen samples. To determine valent state speciation spectroscopic investigations were performed also. Initial yellow uranium phosphate precipitate was separated and identified as uramphite - (NH 4 )(UO 2 )(PO 4 )*3H 2 O by X-Ray Powder Diffraction. Grey precipitate, which was formed by bacterial reduction, was identified as ningyoite - CaU(PO 4 ) 2 *H 2 O. The fact that final grey precipitate contain U(IV) was also confirmed by EXAFS investigation. High concentration of uranium has toxic effect. 1 and 2.5 mM of uranium (VI) support bacterial growth and bacterial biomass was accumulated, but if 5 or 10

  15. Supplementary Material for: Lignocellulose-derived thin stillage composition and efficient biological treatment with a high-rate hybrid anaerobic bioreactor system

    KAUST Repository

    Oosterkamp, Margreet

    2016-01-01

    Abstract 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

  16. Characterization of Probiotic Fermented Milk Prepared by Different Inoculation Size of Mesophilic and Thermophilic Lactic Acid Bacteria

    Directory of Open Access Journals (Sweden)

    Sara Nasiri Boosjin

    2016-10-01

    Full Text Available Background and Objectives: Importance of development of novel probiotic fermented milk and challenge made for its acceptability is well known. In this research, the impact of different inoculation sizes of yogurt and DL-type starter culture (mesophilic and thermophilic LAB on titratable acidity, viscosity, sensorial and microbial properties of fermented milk was investigated; and finally, probiotic Langfil was produced.Materials and Methods: Fermented milk produced by 1, 2 and 3% v v-1 inocula consisting thermophilic: mesophilic starter cultures 10:90 (Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cremoris, Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. lactis biovar. diacetylactis and Leuconostoc mesenteroides subsp. cremoris. Streptococcus thermophilus and Lactobacillus delbrueckii subsp. Bulgaricus were analyzed for determination of titratable acidity, viscosity, viability of mesophilic starter cultures and sensory properties on days 5, 10, and 15 of storage at 4°C. Then, the most suitable treatments were selected for the producing probiotic Langfil, containing probiotic starter culture (2% v v-1 inoculums with equal ratio of Lactobacillus acidophilus and Bifidobacterium bifidum. Lactococcus lactis and L. cremoris were counted on M17 agar, while Leuconostoc and Lactobacillus were counted aerobically on tomato juice agar and MRS bile agar, respectively. Bifidobacterium was cultured anaerobically on MRS bile agar. Sensory evaluation was carried out by ten trained panelists, based on a nine-point hedonic scale during the cold storage.Results and Conclusion: According to results, the best organoleptic properties were achieved in the product prepared with 2% the mesophilic and thermophilic starter cultures and 2% probiotic. This product had a high viscosity. An Iranian probiotic Langfil with desired properties was produced using the best treatment prepared.Conflict of interests: The authors declare no conflict of

  17. Cellulose- and xylan-degrading thermophilic anaerobic bacteria from biocompost.

    Science.gov (United States)

    Sizova, M V; Izquierdo, J A; Panikov, N S; Lynd, L R

    2011-04-01

    Nine thermophilic cellulolytic clostridial isolates and four other noncellulolytic bacterial isolates were isolated from self-heated biocompost via preliminary enrichment culture on microcrystalline cellulose. All cellulolytic isolates grew vigorously on cellulose, with the formation of either ethanol and acetate or acetate and formate as principal fermentation products as well as lactate and glycerol as minor products. In addition, two out of nine cellulolytic strains were able to utilize xylan and pretreated wood with roughly the same efficiency as for cellulose. The major products of xylan fermentation were acetate and formate, with minor contributions of lactate and ethanol. Phylogenetic analyses of 16S rRNA and glycosyl hydrolase family 48 (GH48) gene sequences revealed that two xylan-utilizing isolates were related to a Clostridium clariflavum strain and represent a distinct novel branch within the GH48 family. Both isolates possessed high cellulase and xylanase activity induced independently by either cellulose or xylan. Enzymatic activity decayed after growth cessation, with more-rapid disappearance of cellulase activity than of xylanase activity. A mixture of xylan and cellulose was utilized simultaneously, with a significant synergistic effect observed as a reduction of lag phase in cellulose degradation.

  18. Thermophilic lignocellulose deconstruction.

    Science.gov (United States)

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

    2014-05-01

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

  19. Microbial Ecology of Thermophilic Anaerobic Digestion. Final Report

    Science.gov (United States)

    Zinder, Stephen H.

    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.

  20. 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.

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

  2. 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.

  3. 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

    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

  4. Anaerobic digestion of macroalgal biomass and sediments sourced from the Orbetello lagoon, Italy

    International Nuclear Information System (INIS)

    Migliore, G.; Alisi, C.; Sprocati, A.R.; Massi, E.; Ciccoli, R.; Lenzi, M.; Wang, A.; Cremisini, C.

    2012-01-01

    The anaerobic digestion of marine macroalgae biomass could meet two currently important needs, the mitigation of the eutrophication effects and the production of renewable energy. Because of the abundance of seaweed biomass its conversion can be highly desirable and convenient, mostly for countries with long coastlines or eutrophic environments. The aim of the present work is to carry out an exploratory study of biogas production from macroalgal biomass collected from the Orbetello lagoon (Tuscany, Italy) by solely exploiting the intrinsic degradation potential of the ecosystem. A fresh algae mix and sediments has been used, as both feed and inoculum of an anaerobic digestion process under psychro-mesophilic, mesophilic and thermophilic conditions, in batch reactors, without any washing and drying treatment. The presence of sediment proved to be crucial in order to achieve a good methane yield (methane yield of 380 dm 3 kg −1 VS added ) comparable with literature data obtained through different approaches. The results gave evidence that such an approach will have to be considered when planning a selective anaerobic digestion of macroalgae that could be useful in local applications for coasts and eutrophic lagoons affected by seasonal or frequent algal blooms. -- Highlights: ► Biogas production from macroalgal biomass with minimal energy input is proposed. ► Psychro-mesophilic, mesophilic and thermophilic conditions were compared. ► Highly adapted bacterial pool was crucial to achieve a good methane yield. ► The applied process exploits the intrinsic degradation potential of the ecosystem.

  5. Biogeochemical evidence that thermophilic Archaea mediate the anaerobic oxidation of methane

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Schouten, S.; Wakeham, S.G.; Hopmans, E.C.

    2003-01-01

    Distributions and isotopic analyses of lipids from sediment cores at a hydrothermally active site in the Guaymas Basin with a steep sedimentary temperature gradient revealed the presence of archaea that oxidize methane anaerobically. The presence of strongly 13C-depleted lipids at greater depths in

  6. Genomic Analysis of Caldithrix abyssi, the Thermophilic Anaerobic Bacterium of the Novel Bacterial Phylum Calditrichaeota.

    Science.gov (United States)

    Kublanov, Ilya V; Sigalova, Olga M; Gavrilov, Sergey N; Lebedinsky, Alexander V; Rinke, Christian; Kovaleva, Olga; Chernyh, Nikolai A; Ivanova, Natalia; Daum, Chris; Reddy, T B K; Klenk, Hans-Peter; Spring, Stefan; Göker, Markus; Reva, Oleg N; Miroshnichenko, Margarita L; Kyrpides, Nikos C; Woyke, Tanja; Gelfand, Mikhail S; Bonch-Osmolovskaya, Elizaveta A

    2017-01-01

    The genome of Caldithrix abyssi , the first cultivated representative of a phylum-level bacterial lineage, was sequenced within the framework of Genomic Encyclopedia of Bacteria and Archaea (GEBA) project. The genomic analysis revealed mechanisms allowing this anaerobic bacterium to ferment peptides or to implement nitrate reduction with acetate or molecular hydrogen as electron donors. The genome encoded five different [NiFe]- and [FeFe]-hydrogenases, one of which, group 1 [NiFe]-hydrogenase, is presumably involved in lithoheterotrophic growth, three other produce H 2 during fermentation, and one is apparently bidirectional. The ability to reduce nitrate is determined by a nitrate reductase of the Nap family, while nitrite reduction to ammonia is presumably catalyzed by an octaheme cytochrome c nitrite reductase εHao. The genome contained genes of respiratory polysulfide/thiosulfate reductase, however, elemental sulfur and thiosulfate were not used as the electron acceptors for anaerobic respiration with acetate or H 2 , probably due to the lack of the gene of the maturation protein. Nevertheless, elemental sulfur and thiosulfate stimulated growth on fermentable substrates (peptides), being reduced to sulfide, most probably through the action of the cytoplasmic sulfide dehydrogenase and/or NAD(P)-dependent [NiFe]-hydrogenase (sulfhydrogenase) encoded by the genome. Surprisingly, the genome of this anaerobic microorganism encoded all genes for cytochrome c oxidase, however, its maturation machinery seems to be non-operational due to genomic rearrangements of supplementary genes. Despite the fact that sugars were not among the substrates reported when C. abyssi was first described, our genomic analysis revealed multiple genes of glycoside hydrolases, and some of them were predicted to be secreted. This finding aided in bringing out four carbohydrates that supported the growth of C. abyssi : starch, cellobiose, glucomannan and xyloglucan. The genomic analysis

  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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. 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...

  9. 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.

  10. Anaerobic digestion of vinasses: determination of biomass; Digestion anaerobia de vinazas de vino: determinacion de la biomasa viable

    Energy Technology Data Exchange (ETDEWEB)

    Solera, R.; Romero, L.; Salles, D.

    2002-07-01

    In this paper, we studied the thermophilic anaerobic treatment of vinasses. The viable bacterial population was quantified by soil medium plating techniques, employing an anaerobic chamber for spreading into plates and subsequent incubation of inoculated plates. This technique has been applied to the measurement of the microbial population contained in both single and tow-stage, laboratory-scale reactors. In the single-stage process the main reaction steps-acidogenesis and methano genesis-take place in the same reactor, while in the two-stage process they take place in separate reactors. (Author) 11 refs.

  11. Biogas final digestive byproduct applied to croplands as fertilizer contains high levels of steroid hormones

    DEFF Research Database (Denmark)

    Rodriguez-Navas, Carlos; Björklund, Erland; Halling-Sørensen, Bent

    2013-01-01

    that utilize different anaerobic digestion technologies (mesophilic and thermophilic) from swine manure and other organic wastes. Individual hormone concentration levels were observed up to 1478 ng g(-1) dry weight or 22.5 mg kg(-1) N with estrone and progesterone reaching highest concentration levels....... Evaluation of the potential environmental burden through the application in agriculture was also assessed on the basis of predicted environmental concentrations. This study indicates that the biogas digestion process does not completely remove steroid hormones from livestock manure and use of final digestate......In this study we evaluate and demonstrate the occurrence of nine natural and one synthetic steroid hormone, including estrogens, androgens and progestagens in biogas final digestate byproduct (digestion liquid) commonly used as an agricultural fertilizer. We investigated two biogas sites...

  12. The cellulase activity of an extreme thermophile

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-05-01

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

  13. Methanogenesis in Thermophilic Biogas Reactors

    DEFF Research Database (Denmark)

    Ahring, Birgitte Kiær

    1995-01-01

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

  14. 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...

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

    Science.gov (United States)

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

    2016-12-01

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

  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

    The extremely thermophilic ethanol-producing strain A3 was isolated from a hot spring in Iceland, The cells were rod-shaped, motile, and had terminal spores: cells from the mid-to-late exponential growth phase stained gram-variable but had a gram-positive cell wall structure when viewed...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-07-01

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

  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

  19. Winery waste recycling through anaerobic co-digestion with waste activated sludge.

    Science.gov (United States)

    Da Ros, C; Cavinato, C; Pavan, P; Bolzonella, D

    2014-11-01

    In this study biogas and high quality digestate were recovered from winery waste (wine lees) through anaerobic co-digestion with waste activated sludge both in mesophilic and thermophilic conditions. The two conditions studied showed similar yields (0.40 m(3)/kgCODfed) but different biological process stability: in fact the mesophilic process was clearly more stable than the thermophilic one in terms of bioprocess parameters. The resulting digestates showed good characteristics for both the tested conditions: heavy metals, dioxins (PCDD/F), and dioxin like bi-phenyls (PCBs) were concentred in the effluent if compared with the influent because of the important reduction of the solid dry matter, but remained at levels acceptable for agricultural reuse. Pathogens in digestate decreased. Best reductions were observed in thermophilic condition, while at 37°C the concentration of Escherichia coli was at concentrations level as high as 1000 UFC/g. Dewatering properties of digestates were evaluated by means of the capillary suction time (CST) and specific resistance to filtration (SRF) tests and it was found that a good dewatering level was achievable only when high doses of polymer (more than 25 g per kg dry solids) were added to sludge. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. 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). Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. 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

    The effect of mixing on anaerobic digestion of manure was evaluated in lab-scale and pilot-scale experiments at 55 °C. The effect of continuous (control), minimal (mixing for 10 min prior to extraction/feeding) and intermittent mixing (withholding mixing for 2 h prior to extraction/feeding) on me...

  2. 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)

  3. ENDOSPORES OF THERMOPHILIC FERMENTATIVE BACTERIA

    DEFF Research Database (Denmark)

    Volpi, Marta

    2016-01-01

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

  4. 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.

  5. 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.

  6. Early Microbial Evolution: The Age of Anaerobes.

    Science.gov (United States)

    Martin, William F; Sousa, Filipa L

    2015-12-18

    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. Copyright © 2016 Cold Spring Harbor Laboratory Press; all rights reserved.

  7. Thermophilic Fungi: Their Physiology and Enzymes†

    Science.gov (United States)

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

    2000-01-01

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

  8. 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

  9. 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)

  10. Anaerobic composting of waste organic fraction. Compostaje anaerobico de la fraccion organica de los residuos

    Energy Technology Data Exchange (ETDEWEB)

    Baere, L. de; Verdonck, O.; Verstraete, W.

    1994-01-01

    The dry anaerobic composting can be carried out in mesophilic and thermophilic conditions. Gas production of 6,2 and 8.5 m''3 biogas m''3 daily in laboratory fermenters was obtained. The quality of waste is higher than obtained in aerobic process. The streptococcus sludge was destroyed. This experimental can be applied for big scale and it permits energy recovery and organic compost of municipal solid wastes. (Author)

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

    Science.gov (United States)

    Singh, Bijender

    2016-01-01

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

  12. 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.

  13. Biohydrogen and methane production by co-digestion of cassava stillage and excess sludge under thermophilic condition.

    Science.gov (United States)

    Wang, Wen; Xie, Li; Chen, Jinrong; Luo, Gang; Zhou, Qi

    2011-02-01

    Thermophilic anaerobic hydrogen and methane production by co-digestion of cassava stillage (CS) and excess sludge (ES) was investigated in this study. The improved hydrogen and subsequent methane production were observed by co-digestion of CS with certain amount of ES in batch experiments. Compared with one phase anaerobic digestion, two phase anaerobic digestion offered an attractive alternative with more abundant biogas production and energy yield, e.g., the total energy yield in two phase obtained at VS(CS)/VS(ES) of 3:1 was 25% higher than the value of one phase. Results from continuous experiments further demonstrated that VS(CS)/VS(ES) of 3:1 was optimal for hydrogen production with the highest hydrogen yield of 74 mL/gtotal VS added, the balanced nutrient condition with C/N ratio of 1.5 g carbohydrate-COD/gprotein-COD or 11.9 g C/gN might be the main reason for such enhancement. VS(CS)/VS(ES) of 3:1 was also optimal for continuous methane production considering the higher methane yield of 350 mL/gtotal VS added and the lower propionate concentration in the effluent. Copyright © 2010 Elsevier Ltd. All rights reserved.

  14. 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.

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

    Science.gov (United States)

    Radianingtyas, Helia; Wright, Phillip C

    2003-12-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-01-01

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

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

    DEFF Research Database (Denmark)

    Elsgaard, Lars; Prieur, Daniel

    2010-01-01

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

  18. 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%. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Anaerobic digestion of food waste - Effect of recirculation and temperature on performance and microbiology.

    Science.gov (United States)

    Zamanzadeh, Mirzaman; Hagen, Live H; Svensson, Kine; Linjordet, Roar; Horn, Svein J

    2016-06-01

    Recirculation of digestate was investigated as a strategy to dilute the food waste before feeding to anaerobic digesters, and its effects on microbial community structure and performance were studied. Two anaerobic digesters with digestate recirculation were operated at 37 °C (MD + R) and 55 °C (TD + R) and compared to two additional digesters without digestate recirculation operated at the same temperatures (MD and TD). The MD + R digester demonstrated quite stable and similar performance to the MD digester in terms of the methane yield (around 480 mL CH4 per gVSadded). In both MD and MD + R Methanosaeta was the dominant archaea. However, the bacterial community structure was significantly different in the two digesters. Firmicutes dominated in the MD + R, while Chloroflexi was the dominant phylum in the MD. Regarding the thermophilic digesters, the TD + R showed the lowest methane yield (401 mL CH4 per gVSadded) and accumulation of VFAs. In contrast to the mesophilic digesters, the microbial communities in the thermophilic digesters were rather similar, consisting mainly of the phyla Firmicutes, Thermotoga, Synergistetes and the hydrogenotrophic methanogen Methanothermobacter. The impact of ammonia inhibition was different depending on the digesters configurations and operating temperatures. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    OpenAIRE

    Oosterkamp, Margreet J.; M?ndez-Garc?a, Celia; Kim, Chang-H.; Bauer, Stefan; Ib??ez, Ana B.; Zimmerman, Sabrina; Hong, Pei-Ying; Cann, Isaac K.; Mackie, Roderick I.

    2016-01-01

    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 o...

  1. Factors controlling pathogen destruction during anaerobic digestion of biowastes

    International Nuclear Information System (INIS)

    Smith, S.R.; Lang, N.L.; Cheung, K.H.M.; Spanoudaki, K.

    2005-01-01

    Anaerobic digestion is the principal method of stabilising biosolids from urban wastewater treatment in the UK, and it also has application for the treatment of other types of biowaste. Increasing awareness of the potential risks to human and animal health from environmental sources of pathogens has focused attention on the efficacy of waste treatment processes at destroying pathogenic microorganisms in biowastes recycled to agricultural land. The degree of disinfection achieved by a particular anaerobic digester is influenced by a variety of interacting operational variables and conditions, which can often deviate from the ideal. Experimental investigations demonstrate that Escherichia coli and Salmonella spp. are not damaged by mesophilic temperatures, whereas rapid inactivation occurs by thermophilic digestion. A hydraulic, biokinetic and thermodynamic model of pathogen inactivation during anaerobic digestion showed that a 2 log 10 reduction in E. coli (the minimum removal required for agricultural use of conventionally treated biosolids) is likely to challenge most conventional mesophilic digesters, unless strict maintenance and management practices are adopted to minimise dead zones and by-pass flow. Efficient mixing and organic matter stabilisation are the main factors controlling the rate of inactivation under mesophilic conditions and not a direct effect of temperature per se on pathogenic organisms

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

    International Nuclear Information System (INIS)

    Watanabe, L.; Arni, R.K.

    1996-01-01

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

  3. Anaerobic digestion of slaughterhouse by-products

    International Nuclear Information System (INIS)

    Hejnfelt, Anette; Angelidaki, Irini

    2009-01-01

    Anaerobic digestion of animal by-products was investigated in batch and semi-continuously fed, reactor experiments at 55 o C and for some experiments also at 37 o 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 3 kg -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 -3 and 7 g N dm -3 respectively. Pretreatment (pasteurization: 70 o C, sterilization: 133 o 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 o C showed 40% higher methane production compared to digestion of manure alone.

  4. 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)

  5. 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

  6. Thermophilic anaerobic degradation of butyrate by a butyrate-utilizing bacterium in coculture and triculture with methanogenic bacteria.

    Science.gov (United States)

    Ahring, B K; Westermann, P

    1987-02-01

    We studied syntrophic butyrate degradation in thermophilic mixed cultures containing a butyrate-degrading bacterium isolated in coculture with Methanobacterium thermoautotrophicum or in triculture with M. thermoautotrophicum and the TAM organism, a thermophilic acetate-utilizing methanogenic bacterium. Butyrate was beta-oxidized to acetate with protons as the electron acceptors. Acetate was used concurrently with its production in the triculture. We found a higher butyrate degradation rate in the triculture, in which both hydrogen and acetate were utilized, than in the coculture, in which acetate accumulated. Yeast extract, rumen fluid, and clarified digestor fluid stimulated butyrate degradation, while the effect of Trypticase was less pronounced. Penicillin G, d-cycloserine, and vancomycin caused complete inhibition of butyrate utilization by the cultures. No growth or degradation of butyrate occurred when 2-bromoethanesulfonic acid or chloroform, specific inhibitors of methanogenic bacteria, was added to the cultures and common electron acceptors such as sulfate, nitrate, and fumarate were not used with butyrate as the electron donor. Addition of hydrogen or oxygen to the gas phase immediately stopped growth and butyrate degradation by the cultures. Butyrate was, however, metabolized at approximately the same rate when hydrogen was removed from the cultures and was metabolized at a reduced rate in the cultures previously exposed to hydrogen.

  7. Microbial conversion of food wastes for biofertilizer production with thermophilic lipolytic microbes

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Shu-Hsien; Yang, Shang-Shyng [Institute of Microbiology and Biochemistry, National Taiwan University, Taipei 10617, (Taiwan); Liu, Ching-Piao [Department of Biological Science and Technology, Meiho Institute of Technology, Pingtung 91201, (Taiwan)

    2007-05-15

    Food waste is approximately one quarter of the total garbage in Taiwan. To investigate the feasibility of microbial conversion of food waste to multiple functional biofertilizer, food waste was mixed with bulking materials, inoculated with thermophilic and lipolytic microbes and incubated at 50{sup o}C in a mechanical composter. Microbial inoculation enhanced the degradation of food wastes, increased the total nitrogen and the germination rate of alfalfa seed, shortened the maturity period and improved the quality of biofertilizer. In food waste inoculated with thermophilic and lipolytic Brevibacillus borstelensis SH168 for 28 days, total nitrogen increased from 2.01% to 2.10%, ash increased from 24.94% to 29.21%, crude fat decreased from 4.88% to 1.34% and the C/N ratio decreased from 18.02 to 17.65. Each gram of final product had a higher population of thermophilic microbes than mesophilic microbes. Microbial conversion of food waste to biofertilizer is a feasible and potential technology in the future to maintain the natural resources and to reduce the impact on environmental quality. (author)

  8. Anaerobic codigestion of municipal, farm, and industrial organic wastes: A survey of recent literature

    DEFF Research Database (Denmark)

    Alatriste-Mondragon, Felipe; Samar, P.; Cox, H.H.J.

    2006-01-01

    increase digester gas production and provide savings in the overall energy costs of plant operations. Methane recovery also helps to reduce the emission of greenhouse gases to the atmosphere. The goal of this literature survey was to summarize the research conducted in the last four years on anaerobic......-stage processes), and the operation temperature (e.g., mesophilic or thermophilic). Only a few reports on pilot; and full-scale studies were found. These evaluate general process performance and pretreatment of codigestates, energy production, and treatment costs....

  9. Microbial Insight into a Pilot-Scale Enhanced Two-Stage High-Solid Anaerobic Digestion System Treating Waste Activated Sludge.

    Science.gov (United States)

    Wu, Jing; Cao, Zhiping; Hu, Yuying; Wang, Xiaolu; Wang, Guangqi; Zuo, Jiane; Wang, Kaijun; Qian, Yi

    2017-11-30

    High solid anaerobic digestion (HSAD) is a rapidly developed anaerobic digestion technique for treating municipal sludge, and has been widely used in Europe and Asia. Recently, the enhanced HSAD process with thermal treatment showed its advantages in both methane production and VS reduction. However, the understanding of the microbial community is still poor. This study investigated microbial communities in a pilot enhanced two-stage HSAD system that degraded waste activated sludge at 9% solid content. The system employed process "thermal pre-treatment (TPT) at 70 °C, thermophilic anaerobic digestion (TAD), and mesophilic anaerobic digestion (MAD)". Hydrogenotrophic methanogens Methanothermobacter spp. dominated the system with relative abundance up to about 100% in both TAD and MAD. Syntrophic acetate oxidation (SAO) bacteria were discovered in TAD, and they converted acetate into H₂ and CO₂ to support hydrogenotrophic methanogenesis. The microbial composition and conversion route of this system are derived from the high solid content and protein content in raw sludge, as well as the operational conditions. This study could facilitate the understanding of the enhanced HSAD process, and is of academic and industrial importance.

  10. 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

    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...... (methane productivity and yield) and operational parameter (concentration of ammonia and volatile fatty acid) values were reasonable and displayed good correlation and accuracy. The model was later applied to identify optimal scenarios for an urban organic waste co-digestion process. The simulation...

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

    Directory of Open Access Journals (Sweden)

    Geng Wu

    2017-07-01

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

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

    Science.gov (United States)

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

    2017-01-01

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

  13. Purification and characterization of an endoglucanase from a newly isolated thermophilic anaerobic bacterium

    Energy Technology Data Exchange (ETDEWEB)

    Creuzet, N; Frixon, C [Laboratoire de Chimie Bacterienne, C.N.R.S., 13 - Marseille (France)

    1983-02-01

    An endoglucanase (1,4-..beta..-D-glucan glucanohydrolase, EC 3.2.1.4) from a new cellulotytic thermophilic bacterium was purified to apparent homogeneity after being separated from a xylanase. Little carbohydrate was associated with the endoglucanase. A molecular weight of 91,000 and 99,000 was determined by SDS-polyacrylamide gel electrophoresis and by gel filtration of the native enzyme on Ultrogel ACA 34. The optimal pH was approximately 6.4 and the enzyme was isoelectric at pH 3.85. The enzyme was found highly thermostable: it retained 50% of its activity after 1 hour at 85/sup 0/C. Hydrolysis of CMC took place with a rapid decrease in viscosity but a slow liberation of reducing sugars, indicating to hydrolyze highly ordered cellulose. Cellobiose inhibited the activity of the endoglucanase. None of the metal ions tested stimulated the activity. The enzyme was completely inactivated by 1 mM Hg/sup 2 +/ and was inhibited by thiol reagents.

  14. Evaluation of biogas production potential by dry anaerobic digestion of switchgrass--animal manure mixtures.

    Science.gov (United States)

    Ahn, H K; Smith, M C; Kondrad, S L; White, J W

    2010-02-01

    Anaerobic digestion is a biological method used to convert organic wastes into a stable product for land application with reduced environmental impacts. The biogas produced can be used as an alternative renewable energy source. Dry anaerobic digestion [>15% total solid (TS)] has an advantage over wet digestion (anaerobic digestion of animal manure-switchgrass mixture was evaluated under dry (15% TS) and thermophilic conditions (55 degrees C). Three different mixtures of animal manure (swine, poultry, and dairy) and switchgrass were digested using batch-operated 1-L reactors. The swine manure test units showed 52.9% volatile solids (VS) removal during the 62-day trial, while dairy and poultry manure test units showed 9.3% and 20.2%, respectively. Over the 62 day digestion, the swine manure test units yielded the highest amount of methane 0.337 L CH4/g VS, while the dairy and poultry manure test units showed very poor methane yield 0.028 L CH4/g VS and 0.002 L CH4/g VS, respectively. Although dairy and poultry manure performed poorly, they may still have high potential as biomass for dry anaerobic digestion if appropriate designs are developed to prevent significant volatile fatty acid (VFA) accumulation and pH drop.

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

    Science.gov (United States)

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

    2012-05-25

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

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

    Science.gov (United States)

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

    2015-01-01

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

  17. Anaerobic digestion for treatment of stillage from cellulosic bioethanol production.

    Science.gov (United States)

    Tian, Zhuoli; Mohan, Gayathri Ram; Ingram, Lonnie; Pullammanappallil, Pratap

    2013-09-01

    Thermophilic anaerobic digestion of stillage from a cellulosic ethanol process that uses sugarcane bagasse as feedstock was investigated. A biochemical methane potential (BMP) of 200 ml CH4 at STP (g VS)(-1) was obtained. The whole stillage was separated into two fractions: a fraction retained on 0.5 mm screen called residue and a fraction passing through 0.5 mm screen called filtrate. About 70% of total methane yield of stillage was produced from the filtrate. The filtrate was anaerobically digested in a 15 L semi-continuously fed digester operated for 91 days at HRTs of 21 and 14 days and organic loading rate (OLR) of 1.85 and 2.39 g COD L(-1) d(-1). The methane yield from the stillage from the digester was about 90% of the yield from the BMP assays. The influent soluble COD (sCOD) was reduced from between 35.4 and 38.8 g COD (L(-1)) to between 7.5 and 8 g COD (L(-1)). Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. 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.

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

    Directory of Open Access Journals (Sweden)

    Duo-Chuan Li

    2011-01-01

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

  20. Coupling of anaerobic waste treatment to produce protein- and lipid-rich bacterial biomass

    Science.gov (United States)

    Steinberg, Lisa M.; Kronyak, Rachel E.; House, Christopher H.

    2017-11-01

    Future long-term manned space missions will require effective recycling of water and nutrients as part of a life support system. Biological waste treatment is less energy intensive than physicochemical treatment methods, yet anaerobic methanogenic waste treatment has been largely avoided due to slow treatment rates and safety issues concerning methane production. However, methane is generated during atmosphere regeneration on the ISS. Here we propose waste treatment via anaerobic digestion followed by methanotrophic growth of Methylococcus capsulatus to produce a protein- and lipid-rich biomass that can be directly consumed, or used to produce other high-protein food sources such as fish. To achieve more rapid methanogenic waste treatment, we built and tested a fixed-film, flow-through, anaerobic reactor to treat an ersatz wastewater. During steady-state operation, the reactor achieved a 97% chemical oxygen demand (COD) removal rate with an organic loading rate of 1740 g d-1 m-3 and a hydraulic retention time of 12.25 d. The reactor was also tested on three occasions by feeding ca. 500 g COD in less than 12 h, representing 50x the daily feeding rate, with COD removal rates ranging from 56-70%, demonstrating the ability of the reactor to respond to overfeeding events. While investigating the storage of treated reactor effluent at a pH of 12, we isolated a strain of Halomonas desiderata capable of acetate degradation under high pH conditions. We then tested the nutritional content of the alkaliphilic Halomonas desiderata strain, as well as the thermophile Thermus aquaticus, as supplemental protein and lipid sources that grow in conditions that should preclude pathogens. The M. capsulatus biomass consisted of 52% protein and 36% lipids, the H. desiderata biomass consisted of 15% protein and 7% lipids, and the Thermus aquaticus biomass consisted of 61% protein and 16% lipids. This work demonstrates the feasibility of rapid waste treatment in a compact reactor design

  1. 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

  2. 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

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

    DEFF Research Database (Denmark)

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

    2018-01-01

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

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

    International Nuclear Information System (INIS)

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

    2011-01-01

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

  5. Thermophilic Sulfate-Reducing Bacteria in Cold Marine Sediment

    DEFF Research Database (Denmark)

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

    1994-01-01

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

  6. Thermophilic Sulfate-Reducing Bacteria in Cold Marine Sediment

    DEFF Research Database (Denmark)

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

    1994-01-01

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

  7. 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

  8. Exploring optimal conditions for thermophilic fermentative hydrogen production from cassava stillage

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Gang; Zou, Zhonghai; Wang, Wen [Key Laboratory of Yangtze River Water Environment, Ministry(Tongji University), Siping Road no 1239, Shanghai 200092 (China); Xie, Li; Zhou, Qi [Key Laboratory of Yangtze River Water Environment, Ministry(Tongji University), Siping Road no 1239, Shanghai 200092 (China); UNEP-Tongji University Institute of Environment for Sustainable Development, Siping Road no 1239, Shanghai 200092 (China)

    2010-06-15

    This study investigated the effects of seed sludges, alkalinity and HRT on the thermophilic fermentative hydrogen production from cassava stillage. Five different kinds of sludges were used as inocula without any pretreatment. Though batch experiments showed that mesophilic anaerobic sludge was the best inoculum, the hydrogen yields with different seed sludges were quite similar in continuous experiments in the range of 82.9-92.3 ml H{sub 2}/gVS without significant differences which could be attributed to the establishment of Uncultured Thermoanaerobacteriaceae bacterium-dominant microbial communities in all reactors. It is indicated that results obtained from batch experiments are not consistent with those from continuous experiments and all the tested seed sludges are good sources for continuous thermophilic hydrogen production from cassava stillage. The influent alkalinity of 6 g NaHCO{sub 3}/L and HRT 24 h were optimal for hydrogen production with hydrogen yield of 76 ml H{sub 2}/gVS and hydrogen production rate of 3215 ml H{sub 2}/L/d. Butyrate was the predominant metabolite in all experiments. With the increase in alkalinity of more than 6 g/L, the concentration of VFA/ethanol increased while hydrogen yield decreased due to the higher concentration of acetate and propionate. The decrease in HRT resulted in the higher hydrogen production rate but lower hydrogen yield. Variation of hydrogen yields were quite correlated with butyrate/acetate (B/A) ratio with different influent alkalinities, however, butyrate was important parameter to justify the hydrogen yields with various HRTs. (author)

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

    Science.gov (United States)

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

    2015-01-01

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

  10. 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)

  11. 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.

  12. 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

    of phylum Actinobacteria in both R1 and R2, and a predominance of phyla Synergistetes and Firmicutes in R3 during Run II. Furthermore, R1 and R2 shared genera (Prevotella, Aminobacterium, Geobacillus and Unclassified Actinobacteria), which suggests synergy between mesophilic anaerobic digestion...

  13. 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.

  14. Thermophilic Alkaline Fermentation Followed by Mesophilic Anaerobic Digestion for Efficient Hydrogen and Methane Production from Waste-Activated Sludge: Dynamics of Bacterial Pathogens as Revealed by the Combination of Metagenomic and Quantitative PCR Analyses.

    Science.gov (United States)

    Wan, Jingjing; Jing, Yuhang; Rao, Yue; Zhang, Shicheng; Luo, Gang

    2018-03-15

    Thermophilic alkaline fermentation followed by mesophilic anaerobic digestion (TM) for hydrogen and methane production from waste-activated sludge (WAS) was investigated. The TM process was also compared to a process with mesophilic alkaline fermentation followed by a mesophilic anaerobic digestion (MM) and one-stage mesophilic anaerobic digestion (M) process. The results showed that both hydrogen yield (74.5 ml H 2 /g volatile solids [VS]) and methane yield (150.7 ml CH 4 /g VS) in the TM process were higher than those (6.7 ml H 2 /g VS and 127.8 ml CH 4 /g VS, respectively) in the MM process. The lowest methane yield (101.2 ml CH 4 /g VS) was obtained with the M process. Taxonomic results obtained from metagenomic analysis showed that different microbial community compositions were established in the hydrogen reactors of the TM and MM processes, which also significantly changed the microbial community compositions in the following methane reactors compared to that with the M process. The dynamics of bacterial pathogens were also evaluated. For the TM process, the reduced diversity and total abundance of bacterial pathogens in WAS were observed in the hydrogen reactor and were further reduced in the methane reactor, as revealed by metagenomic analysis. The results also showed not all bacterial pathogens were reduced in the reactors. For example, Collinsella aerofaciens was enriched in the hydrogen reactor, which was also confirmed by quantitative PCR (qPCR) analysis. The study further showed that qPCR was more sensitive for detecting bacterial pathogens than metagenomic analysis. Although there were some differences in the relative abundances of bacterial pathogens calculated by metagenomic and qPCR approaches, both approaches demonstrated that the TM process was more efficient for the removal of bacterial pathogens than the MM and M processes. IMPORTANCE This study developed an efficient process for bioenergy (H 2 and CH 4 ) production from WAS and elucidates the

  15. 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. Copyright © 2016. Published by Elsevier Ltd.

  16. Energy transduction and transport processes in thermophilic bacteria

    NARCIS (Netherlands)

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

    1992-01-01

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

  17. 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)

  18. Thermophilic anaerobic co-digestion of garbage, screened swine and dairy cattle manure.

    Science.gov (United States)

    Liu, Kai; Tang, Yue-Qin; Matsui, Toru; Morimura, Shigeru; Wu, Xiao-Lei; Kida, Kenji

    2009-01-01

    Methane fermentation characteristics of garbage, swine manure (SM), dairy cattle manure (DCM) and mixtures of these wastes were studied. SM and DCM showed much lower volatile total solid (VTS) digestion efficiencies and methane yield than those of garbage. VTS digestion efficiency of SM was significantly increased when it was co-digested with garbage (Garbage: SM=1:1). Co-digestion of garbage, SM and DCM with respect to the relative quantity of each waste discharged in the Kikuchi (1: 16: 27) and Aso (1: 19: 12) areas indicated that co-digestion with garbage would improve the digestion characteristic of SM and DCM as far as the ratio of DCM in the wastes was maintained below a certain level. When the mixed waste (Garbage: SM: DCM=1:19:12) was treated using a thermophilic UAF reactor, methanogens responsible for the methane production were Methanoculleus and Methanosarcina species. Bacterial species in the phylum Firmicutes were dominant bacteria responsible for the digestion of these wastes. As the percentage of garbage in the mixed wastes used in this study was low (2-3%) and the digestion efficiency of DCM was obviously improved, the co-digestion of SM and DCM with limited garbage was a prospective method to treat the livestock waste effectively and was an attractive alternative technology for the construction of a sustainable environment and society in stock raising area.

  19. Anaerobic co-digestion of municipal organic wastes and pre-treatment to enhance biogas production from waste.

    Science.gov (United States)

    Li, Chenxi; Champagne, Pascale; Anderson, Bruce C

    2014-01-01

    Co-digestion and pre-treatment have been recognized as effective, low-cost and commercially viable approaches to reduce anaerobic digestion process limitations and improve biogas yields. In our previous batch-scale study, fat, oil, and grease (FOG) was investigated as a suitable potential co-substrate, and thermo-chemical pre-treatment (TCPT) at pH = 10 and 55 °C improved CH4 production from FOG co-digestions. In this project, co-digestions with FOG were studied in bench-scale two-stage thermophilic semi-continuous flow co-digesters with suitable TCPT (pH = 10, 55 °C). Overall, a 25.14 ± 2.14 L/d (70.2 ± 1.4% CH4) biogas production was obtained, which was higher than in the two-stage system without pre-treatment. The results could provide valuable fundamental information to support full-scale investigations of anaerobic co-digestion of municipal organic wastes.

  20. Comparative economic assessment of ethanol production under mesophilic and thermophilic conditions

    International Nuclear Information System (INIS)

    Mistry, P.B.

    1991-01-01

    Key technical factors affecting the economics of bioethanol production are critically analyzed with special reference to the relative merits of thermophilic and mesophilic fermentation. A number of novel process schemes to take advantage of thermophilic operation are discussed. Analysis of the capital and operating costs for a range of flowsheets then provides a basis for critical study. Estimates for thermophilic production are compared with those for a sugar cane based mesophilic process (using S. cerevisiae). For the thermophilic fermentation, the basic kinetic and yield constants are based on projected values for a strain of B. stearothermophilus. Compared to mesophilic operation, thermophilic operation results in reduced capital, operating and feed costs. The feed cost still accounts for a large proportion (75%) of the total production cost. However, on a feed-cost-free basis, a reduction in production cost of up to 32% could be realized by changing to thermophilic operation from existing yeast-based processes, after minor process modifications. 20 refs., 10 figs., 8 tabs

  1. Cellulolytic potential of thermophilic species from four fungal orders

    DEFF Research Database (Denmark)

    Busk, Peter Kamp; Lange, Lene

    2013-01-01

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

  2. 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)

  3. Thermophilic Fungi: Their Physiology and Enzymes†

    OpenAIRE

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

    2000-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Muhammad Fajar Fajar

    2018-01-01

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

  5. 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

  6. Hydrophobic environment is a key factor for the stability of thermophilic proteins.

    Science.gov (United States)

    Gromiha, M Michael; Pathak, Manish C; Saraboji, Kadhirvel; Ortlund, Eric A; Gaucher, Eric A

    2013-04-01

    The stability of thermophilic proteins has been viewed from different perspectives and there is yet no unified principle to understand this stability. It would be valuable to reveal the most important interactions for designing thermostable proteins for such applications as industrial protein engineering. In this work, we have systematically analyzed the importance of various interactions by computing different parameters such as surrounding hydrophobicity, inter-residue interactions, ion-pairs and hydrogen bonds. The importance of each interaction has been determined by its predicted relative contribution in thermophiles versus the same contribution in mesophilic homologues based on a dataset of 373 protein families. We predict that hydrophobic environment is the major factor for the stability of thermophilic proteins and found that 80% of thermophilic proteins analyzed showed higher hydrophobicity than their mesophilic counterparts. Ion pairs, hydrogen bonds, and interaction energy are also important and favored in 68%, 50%, and 62% of thermophilic proteins, respectively. Interestingly, thermophilic proteins with decreased hydrophobic environments display a greater number of hydrogen bonds and/or ion pairs. The systematic elimination of mesophilic proteins based on surrounding hydrophobicity, interaction energy, and ion pairs/hydrogen bonds, led to correctly identifying 95% of the thermophilic proteins in our analyses. Our analysis was also applied to another, more refined set of 102 thermophilic-mesophilic pairs, which again identified hydrophobicity as a dominant property in 71% of the thermophilic proteins. Further, the notion of surrounding hydrophobicity, which characterizes the hydrophobic behavior of residues in a protein environment, has been applied to the three-dimensional structures of elongation factor-Tu proteins and we found that the thermophilic proteins are enriched with a hydrophobic environment. The results obtained in this work highlight the

  7. Amino Acid Transport in the Thermophilic Anaerobe Clostridium fervidus Is Driven by an Electrochemical Sodium Gradient

    NARCIS (Netherlands)

    SPEELMANS, G; POOLMAN, B; KONINGS, WN

    Amino acid transport was studied in membranes of the peptidolytic, thermophitic, anaerobic bacterium Clostridium fervidus. Uptake of the negatively charged amino acid L-glutamate, the neutral amino acid L-serine, and the positively charged amino acid L-arginine was examined in membrane vesicles

  8. Deletion of the hfsB gene increases ethanol production in Thermoanaerobacterium saccharolyticum and several other thermophilic anaerobic bacteria.

    Science.gov (United States)

    Eminoğlu, Ayşenur; Murphy, Sean Jean-Loup; Maloney, Marybeth; Lanahan, Anthony; Giannone, Richard J; Hettich, Robert L; Tripathi, Shital A; Beldüz, Ali Osman; Lynd, Lee R; Olson, Daniel G

    2017-01-01

    With the discovery of interspecies hydrogen transfer in the late 1960s (Bryant et al. in Arch Microbiol 59:20-31, 1967), it was shown that reducing the partial pressure of hydrogen could cause mixed acid fermenting organisms to produce acetate at the expense of ethanol. Hydrogen and ethanol are both more reduced than glucose. Thus there is a tradeoff between production of these compounds imposed by electron balancing requirements; however, the mechanism is not fully known. Deletion of the hfsA or B subunits resulted in a roughly 1.8-fold increase in ethanol yield. The increase in ethanol production appears to be associated with an increase in alcohol dehydrogenase activity, which appears to be due, at least in part, to increased expression of the adhE gene, and may suggest a regulatory linkage between hfsB and adhE . We studied this system most intensively in the organism Thermoanaerobacterium saccharolyticum ; however, deletion of hfsB also increases ethanol production in other thermophilic bacteria suggesting that this could be used as a general technique for engineering thermophilic bacteria for improved ethanol production in organisms with hfs -type hydrogenases. Since its discovery by Shaw et al. (JAMA 191:6457-64, 2009), the hfs hydrogenase has been suspected to act as a regulator due to the presence of a PAS domain. We provide additional support for the presence of a regulatory phenomenon. In addition, we find a practical application for this scientific insight, namely increasing ethanol yield in strains that are of interest for ethanol production from cellulose or hemicellulose. In two of these organisms ( T. xylanolyticum and T. thermosaccharolyticum ), the ethanol yields are the highest reported to date.

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

    Science.gov (United States)

    Roest, Kees; Altinbas, Mahmut; Paulo, Paula L; Heilig, H G H J; Akkermans, Antoon D L; Smidt, Hauke; de Vos, Willem M; Stams, Alfons J M

    2005-10-01

    To gain insight into the microorganisms involved in direct and indirect methane formation from methanol in a laboratory-scale thermophilic (55 degrees C) methanogenic bioreactor, reactor sludge was disrupted and serial dilutions were incubated in specific growth media containing methanol and possible intermediates of methanol degradation as substrates. With methanol, growth was observed up to a dilution of 10(8). However, when Methanothermobacter thermoautotrophicus strain Z245 was added for H2 removal, growth was observed up to a 10(10)-fold dilution. With H2/CO2 and acetate, growth was observed up to dilutions of 10(9) and 10(4), respectively. Dominant microorganisms in the different dilutions were identified by 16S rRNA-gene diversity and sequence analysis. Furthermore, dilution polymerase chain reaction (PCR) revealed a similar relative abundance of Archaea and Bacteria in all investigated samples, except in enrichment with acetate, which contained 100 times less archaeal DNA than bacterial DNA. The most abundant bacteria in the culture with methanol and strain Z245 were most closely related to Moorella glycerini. Thermodesulfovibrio relatives were found with high sequence similarity in the H2/CO2 enrichment, but also in the original laboratory-scale bioreactor sludge. Methanothermobacter thermoautotrophicus strains were the most abundant hydrogenotrophic archaea in the H2/CO2 enrichment. The dominant methanol-utilizing methanogen, which was present in the 10(8)-dilution, was most closely related to Methanomethylovorans hollandica. Compared to direct methanogenesis, results of this study indicate that syntrophic, interspecies hydrogen transfer-dependent methanol conversion is equally important in the thermophilic bioreactor, confirming previous findings with labeled substrates and specific inhibitors.

  10. 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.

  11. 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...... thermoautotrophicum Delta H, from another genus, in which trkA is not part of the locus. The proteins encoded in the TM-1 genes are very similar to the S-6 homologs, but considerably less similar to the Delta H proteins. The TM-1 Hsp70(DnaK) protein has the 23-amino acid deletion-by comparison with homologs from Gram...

  12. Thermophilic xylanases: from bench to bottle.

    Science.gov (United States)

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

    2018-01-17

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

  13. Thermincola carboxydiphila gen. nov., sp. nov., a novel anaerobic, carboxydotrophic, hydrogenogenic bacterium from a hot spring of the Lake Baikal area.

    Science.gov (United States)

    Sokolova, Tatyana G; Kostrikina, Nadezhda A; Chernyh, Nikolai A; Kolganova, Tatjana V; Tourova, Tatjana P; Bonch-Osmolovskaya, Elizaveta A

    2005-09-01

    A novel anaerobic, thermophilic, alkalitolerant bacterium, strain 2204(T), was isolated from a hot spring of the Baikal Lake region. The cells of strain 2204(T) were straight rods of variable length, Gram-positive with an S-layer, motile with one to two lateral flagella, and often formed aggregates of 3-15 cells. The isolate was shown to be an obligate anaerobe oxidizing CO and producing equimolar quantities of H(2) and CO(2) according to the equation CO+H(2)O-->CO(2)+H(2). No organic substrates were used as energy sources. For lithotrophic growth on CO, 0.2 g acetate or yeast extract l(-1) was required but did not support growth in the absence of CO. Growth was observed in the temperature range 37-68 degrees C, the optimum being 55 degrees C. The pH range for growth was 6.7-9.5, the optimum pH being 8.0. The generation time under optimal conditions was 1.3 h. The DNA G+C content was 45 mol%. Penicillin, erythromycin, streptomycin, rifampicin, vancomycin and tetracycline completely inhibited both growth and CO utilization by strain 2204(T). Thus, isolate 2204(T) was found to be the first known moderately thermophilic and alkalitolerant H(2)-producing anaerobic carboxydotroph. The novel bacterium fell within the cluster of the family Peptococcaceae within the low-G+C-content Gram-positive bacteria, where it formed a separate branch. On the basis of morphological, physiological and phylogenetic features, strain 2204(T) should be assigned to a novel genus and species, for which the name Thermincola carboxydiphila gen. nov., sp. nov. is proposed. The type strain is strain 2204(T) (=DSM 17129(T)=VKM B-2283(T)=JCM 13258(T)).

  14. Genomic Analysis of Caldithrix abyssi, the Thermophilic Anaerobic Bacterium of the Novel Bacterial Phylum Calditrichaeota

    OpenAIRE

    Kublanov, Ilya V.; Sigalova, Olga M.; Gavrilov, Sergey N.; Lebedinsky, Alexander V.; Rinke, Christian; Kovaleva, Olga; Chernyh, Nikolai A.; Ivanova, Natalia; Daum, Chris; Reddy, T.B.K.; Klenk, Hans-Peter; Spring, Stefan; G?ker, Markus; Reva, Oleg N.; Miroshnichenko, Margarita L.

    2017-01-01

    © 2017 Kublanov, Sigalova, Gavrilov, Lebedinsky, Rinke, Kovaleva, Chernyh, Ivanova, Daum, Reddy, Klenk, Spring, Göker, Reva, Miroshnichenko, Kyrpides, Woyke, Gelfand, Bonch-Osmolovskaya. The genome of Caldithrix abyssi, the first cultivated representative of a phylum-level bacterial lineage, was sequenced within the framework of Genomic Encyclopedia of Bacteria and Archaea (GEBA) project. The genomic analysis revealed mechanisms allowing this anaerobic bacterium to ferment peptides or to impl...

  15. Deferribacter thermophilus gen. nov., sp. nov., a novel thermophilic manganese- and iron-reducing bacterium isolated from a petroleum reservoir.

    Science.gov (United States)

    Greene, A C; Patel, B K; Sheehy, A J

    1997-04-01

    A thermophilic anaerobic bacterium, designated strain BMAT (T = type strain), was isolated from the production water of Beatrice oil field in the North Sea (United Kingdom). The cells were straight to bent rods (1 to 5 by 0.3 to 0.5 microns) which stained gram negative. Strain BMAT obtained energy from the reduction of manganese (IV), iron(III), and nitrate in the presence of yeast extract, peptone, Casamino Acids, tryptone, hydrogen, malate, acetate, citrate, pyruvate, lactate, succinate, and valerate. The isolate grew optimally at 60 degrees C (temperature range for growth, 50 to 65 degrees C) and in the presence of 2% (wt/vol) NaCl (NaCl range for growth, 0 to 5% [wt/vol]). The DNA base composition was 34 mol% G + C. Phylogenetic analyses of the 16S rRNA gene indicated that strain BMAT is a member of the domain Bacteria. The closest known bacterium is the moderate thermophile Flexistipes sinusarabici (similarity value, 88%). Strain BMAT possesses phenotypic and phylogenetic traits that do not allow its classification as a member of any previously described genus; therefore, we propose that this isolate should be described as a member of a novel species of a new genus, Deferribacter thermophilus gen. nov., sp. nov.

  16. 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

  17. Bioprospecting thermophiles for cellulase production: a review.

    Science.gov (United States)

    Acharya, Somen; Chaudhary, Anita

    2012-07-01

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

  18. Relationship between microbial community dynamics and process performance during thermophilic sludge bioleaching.

    Science.gov (United States)

    Chen, Shen-Yi; Chou, Li-Chieh

    2016-08-01

    Heavy metals can be removed from the sludge using bioleaching technologies at thermophilic condition, thereby providing an option for biotreatment of wasted sludge generated from wastewater treatment. The purposes of this study were to establish a molecular biology technique, real-time PCR, for the detection and enumeration of the sulfur-oxidizing bacteria during the thermophilic sludge bioleaching. The 16S rRNA gene for real-time PCR quantification targeted the bioleaching bacteria: Sulfobacillus thermosulfidooxidans, Sulfobacillus acidophilus, and Acidithiobacillus caldus. The specificity and stringency for thermophilic sulfur-oxidizing bacteria were tested before the experiments of monitoring the bacterial community, bacterial number during the thermophilic sludge bioleaching and the future application on testing various environmental samples. The results showed that S. acidophilus was identified as the dominant sulfur-oxidizing bacteria, while A. caldus and S. thermosulfidooxidans occurred in relatively low numbers. The total number of the sulfur-oxidizing bacteria increased during the thermophilic bioleaching process. Meanwhile, the decrease of pH, production of sulfate, degradation of SS/VSS, and solubilization of heavy metal were found to correlate well with the population of thermophilic sulfur-oxidizing bacteria during the bioleaching process. The real-time PCR used in this study is a suitable method to monitor numbers of thermophilic sulfur-oxidizing bacteria during the bioleaching process.

  19. The anaerobic corrosion of carbon steel in concrete

    International Nuclear Information System (INIS)

    Naish, C.C.; Balkwill, P.H.; O'Brien, T.M.; Taylor, K.J.; Marsh, G.P.

    1991-01-01

    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 20-30 0 C, ie ambient conditions. 4 refs.; 19 figs.; 6 tabs

  20. Single stage anaerobic digestion process. Megas process. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Malarich, M.

    1985-12-01

    The rate-limiting step in the anaerobic digestion of domestic sewage sludge and agricultural manures is usually considered the conversion of acetate to methane and carbon dioxide. Some reports have suggested that phase transfer of endproduct carbon dioxide from the liquid to gaseous state may be the overall rate-limiting step. Research to date has focused on batch fermentation studies at varying carbon dioxide partial pressures (pCO/sub 2/) using simple substrates such as glucose or acetate. The results indicate that lowering the pCO/sub 2/ may increase methane production and waste stabilization rates. This research was conducted using continuous fermentations. Continuous fermentations using a complex synthetic waste were performed over a five-month period. The results obtained failed to support the findings of earlier batch studies where methane production increased as pCO/sub 2/ decreased. No significant difference in methane production was found between anaerobic digestion at low pCO/sub 2/ (0.1 to 0.15 atm) and normal pCO/sub 2/ (0.4 to 0.5 atm). 15 refs., 8 figs., 2 tabs.

  1. 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)

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

    Science.gov (United States)

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

    2016-01-01

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

  3. Microbial community shifts in a farm-scale anaerobic digester treating swine waste: Correlations between bacteria communities associated with hydrogenotrophic methanogens and environmental conditions.

    Science.gov (United States)

    Cho, Kyungjin; Shin, Seung Gu; Kim, Woong; Lee, Joonyeob; Lee, Changsoo; Hwang, Seokhwan

    2017-12-01

    Microbial community structure in a farm-scale anaerobic digester treating swine manure was investigated during three process events: 1) prolonged starvation, and changes of 2) operating temperature (between meso- and thermophilic) and 3) hydraulic retention time (HRT). Except during the initial period, the digester was dominated by hydrogenotrophic methanogens (HMs). The bacterial community structure significantly shifted with operating temperature and HRT but not with long-term starvation. Clostridiales (26.5-54.4%) and Bacteroidales (2.5-13.7%) became dominant orders in the digester during the period of HM dominance. Abundance of diverse meso- and thermophilic bacteria increased during the same period; many of these species may be H 2 producers, and/or syntrophic acetate oxidizers. Some of these species showed positive correlations with [NH 4 + -N] (panaerobic digesters treating swine manure that contains high ammonia content. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. 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.

  5. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-07-01

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

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

    Directory of Open Access Journals (Sweden)

    Deanne W Sammond

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

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

    Science.gov (United States)

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

    2011-08-15

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

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

    Science.gov (United States)

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

    2015-12-01

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

  10. 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.

  11. 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.

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

    Science.gov (United States)

    Itoh, Takashi; Yoshikawa, Naoto; Takashina, Tomonori

    2005-09-01

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

  13. Application of Biofilm Covered Activated Carbon Particles as a Microbial Inoculum Delivery System for Enhanced Bioaugmentation of PCBs in Contaminated Sediment

    Science.gov (United States)

    2013-09-01

    after anaerobic digestion at thermophilic conditions (60- 70C). Application of biofilm covered activated carbon particles as a microbial inoculum...Sludge Thickener; Sludge = Sludge after anaerobic digestion at thermophilic conditions (60- 70C). C3. Microscopic evaluation of dechlorinating...associated enzymes are capable of opening the biphenyl ring structure and transform the molecule into a linear structure, this changed structure was not

  14. Versatile transformations of hydrocarbons in anaerobic bacteria: substrate ranges and regio- and stereo-chemistry of activation reactions†

    Science.gov (United States)

    Jarling, René; Kühner, Simon; Basílio Janke, Eline; Gruner, Andrea; Drozdowska, Marta; Golding, Bernard T.; Rabus, Ralf; Wilkes, Heinz

    2015-01-01

    Anaerobic metabolism of hydrocarbons proceeds either via addition to fumarate or by hydroxylation in various microorganisms, e.g., sulfate-reducing or denitrifying bacteria, which are specialized in utilizing n-alkanes or alkylbenzenes as growth substrates. General pathways for carbon assimilation and energy gain have been elucidated for a limited number of possible substrates. In this work the metabolic activity of 11 bacterial strains during anaerobic growth with crude oil was investigated and compared with the metabolite patterns appearing during anaerobic growth with more than 40 different hydrocarbons supplied as binary mixtures. We show that the range of co-metabolically formed alkyl- and arylalkyl-succinates is much broader in n-alkane than in alkylbenzene utilizers. The structures and stereochemistry of these products are resolved. Furthermore, we demonstrate that anaerobic hydroxylation of alkylbenzenes does not only occur in denitrifiers but also in sulfate reducers. We propose that these processes play a role in detoxification under conditions of solvent stress. The thermophilic sulfate-reducing strain TD3 is shown to produce n-alkylsuccinates, which are suggested not to derive from terminal activation of n-alkanes, but rather to represent intermediates of a metabolic pathway short-cutting fumarate regeneration by reverse action of succinate synthase. The outcomes of this study provide a basis for geochemically tracing such processes in natural habitats and contribute to an improved understanding of microbial activity in hydrocarbon-rich anoxic environments. PMID:26441848

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

    Science.gov (United States)

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

    2007-08-15

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

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

    Science.gov (United States)

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

    2014-01-01

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

  17. Genome analysis of the anaerobic thermohalophilic bacterium Halothermothrix orenii.

    Directory of Open Access Journals (Sweden)

    Konstantinos Mavromatis

    Full Text Available Halothermothirx orenii is a strictly anaerobic thermohalophilic bacterium isolated from sediment of a Tunisian salt lake. It belongs to the order Halanaerobiales in the phylum Firmicutes. The complete sequence revealed that the genome consists of one circular chromosome of 2578146 bps encoding 2451 predicted genes. This is the first genome sequence of an organism belonging to the Haloanaerobiales. Features of both Gram positive and Gram negative bacteria were identified with the presence of both a sporulating mechanism typical of Firmicutes and a characteristic Gram negative lipopolysaccharide being the most prominent. Protein sequence analyses and metabolic reconstruction reveal a unique combination of strategies for thermophilic and halophilic adaptation. H. orenii can serve as a model organism for the study of the evolution of the Gram negative phenotype as well as the adaptation under thermohalophilic conditions and the development of biotechnological applications under conditions that require high temperatures and high salt concentrations.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1986-01-01

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

  19. Characterization of the arabinoxylan-degrading machinery of the thermophilic bacterium Herbinix hemicellulosilytica-Six new xylanases, three arabinofuranosidases and one xylosidase.

    Science.gov (United States)

    Mechelke, M; Koeck, D E; Broeker, J; Roessler, B; Krabichler, F; Schwarz, W H; Zverlov, V V; Liebl, W

    2017-09-10

    Herbinix hemicellulosilytica is a newly isolated, gram-positive, anaerobic bacterium with extensive hemicellulose-degrading capabilities obtained from a thermophilic biogas reactor. In order to exploit its potential as a source for new industrial arabinoxylan-degrading enzymes, six new thermophilic xylanases, four from glycoside hydrolase family 10 (GH10) and two from GH11, three arabinofuranosidases (1x GH43, 2x GH51) and one β-xylosidase (GH43) were selected. The recombinantly produced enzymes were purified and characterized. All enzymes were active on different xylan-based polysaccharides and most of them showed temperature-vs-activity profiles with maxima around 55-65°C. HPAEC-PAD analysis of the hydrolysates of wheat arabinoxylan and of various purified xylooligosaccharides (XOS) and arabinoxylooligosaccharides (AXOS) was used to investigate their substrate and product specificities: among the GH10 xylanases, XynB showed a different product pattern when hydrolysing AXOS compared to XynA, XynC, and XynD. None of the GH11 xylanases was able to degrade any of the tested AXOS. All three arabinofuranosidases, ArfA, ArfB and ArfC, were classified as type AXH-m,d enzymes. None of the arabinofuranosidases was able to degrade the double-arabinosylated xylooligosaccharides XA 2+3 XX. β-Xylosidase XylA (GH43) was able to degrade unsubstituted XOS, but showed limited activity to degrade AXOS. Copyright © 2017. Published by Elsevier B.V.

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

    Science.gov (United States)

    Svetlitshnyi, V; Rainey, F; Wiegel, J

    1996-10-01

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

  1. Reduction of Fe(III) oxides by phylogenetically and physiologically diverse thermophilic methanogens.

    Science.gov (United States)

    Yamada, Chihaya; Kato, Souichiro; Kimura, Satoshi; Ishii, Masaharu; Igarashi, Yasuo

    2014-09-01

    Three thermophilic methanogens (Methanothermobacter thermautotrophicus, Methanosaeta thermophila, and Methanosarcina thermophila) were investigated for their ability to reduce poorly crystalline Fe(III) oxides (ferrihydrite) and the inhibitory effects of ferrihydrite on their methanogenesis. This study demonstrated that Fe(II) generation from ferrihydrite occurs in the cultures of the three thermophilic methanogens only when H2 was supplied as the source of reducing equivalents, even in the cultures of Mst. thermophila that do not grow on and produce CH4 from H2/CO2. While supplementation of ferrihydrite resulted in complete inhibition or suppression of methanogenesis by the thermophilic methanogens, ferrihydrite reduction by the methanogens at least partially alleviates the inhibitory effects. Microscopic and crystallographic analyses on the ferrihydrite-reducing Msr. thermophila cultures exhibited generation of magnetite on its cell surfaces through partial reduction of ferrihydrite. These findings suggest that at least certain thermophilic methanogens have the ability to extracellularly transfer electrons to insoluble Fe(III) compounds, affecting their methanogenic activities, which would in turn have significant impacts on materials and energy cycles in thermophilic anoxic environments. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  2. Anaerobic digestion of organic solid poultry slaughterhouse waste--a review.

    Science.gov (United States)

    Salminen, E; Rintala, J

    2002-05-01

    This work reviews the potential of anaerobic digestion for material recovery and energy production from poultry slaughtering by-products and wastes. First, we describe and quantify organic solid by-products and wastes produced in poultry farming and poultry slaughterhouses and discuss their recovery and disposal options. Then we review certain fundamental aspects of anaerobic digestion considered important for the digestion of solid slaughterhouse wastes. Finally, we present an overview of the future potential and current experience of the anaerobic digestion treatment of these materials.

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

    Science.gov (United States)

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

    2013-09-01

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

  4. Effect of Recycle Sludge on Anaerobic Digestion of Palm Oil Mill Effluent in A Thermophilic Continuous Digester

    Science.gov (United States)

    Irvan; Trisakti, B.; Tomiuchi, Y.; Harahap, U.; Daimon, H.

    2017-06-01

    The objective of this research is to maintain short retention time and high degradation of palm oil mill effluent (POME) to biogas by applying recycle sludge. Fresh POME from Rambutan Mill without further treatment was used as feed. Two lab-scale digesters supported from Metawater Co. Ltd. have been applied to treat POME at thermophilic (55°C) condition. Both digesters were operated under intermittent operation mode. Experiments were performed in two methods: with and without recycle sludge. Hydraulic retention time (HRT) of both methods was maintained at 6 days, while sludge retention time (SRT) was maintained at various days. The result showed that by extending SRT in return sludge process where 25% of digested slurry recycled to the digester, improvement of volatile solid (VS) decomposition was obtained around 84% at HRT of 6 days and SRT of 21 days. Then, chemical oxygen demand (COD) removal efficiency could be reached until 85% by using recycle sludge.

  5. Continuous thermal hydrolysis and energy integration in sludge anaerobic digestion plants.

    Science.gov (United States)

    Fdz-Polanco, F; Velazquez, R; Perez-Elvira, S I; Casas, C; del Barrio, D; Cantero, F J; Fdz-Polanco, M; Rodriguez, P; Panizo, L; Serrat, J; Rouge, P

    2008-01-01

    A thermal hydrolysis pilot plant with direct steam injection heating was designed and constructed. In a first period the equipment was operated in batch to verify the effect of sludge type, pressure and temperature, residence time and solids concentration. Optimal operation conditions were reached for secondary sludge at 170 degrees C, 7 bar and 30 minutes residence time, obtaining a disintegration factor higher than 10, methane production increase by 50% and easy centrifugation In a second period the pilot plant was operated working with continuous feed, testing the efficiency by using two continuous anaerobic digester operating in the mesophilic and thermophilic range. Working at 12 days residence time, biogas production increases by 40-50%. Integrating the energy transfer it is possible to design a self-sufficient system that takes advantage of this methane increase to produce 40% more electric energy. (c) IWA Publishing 2008.

  6. Fervidicoccus fontis gen. nov., sp. nov., an anaerobic, thermophilic crenarchaeote from terrestrial hot springs, and proposal of Fervidicoccaceae fam. nov. and Fervidicoccales ord. nov.

    Science.gov (United States)

    Perevalova, Anna A; Bidzhieva, Salima Kh; Kublanov, Ilya V; Hinrichs, Kai-Uwe; Liu, Xiaolei L; Mardanov, Andrey V; Lebedinsky, Alexander V; Bonch-Osmolovskaya, Elizaveta A

    2010-09-01

    Two novel thermophilic and slightly acidophilic strains, Kam940(T) and Kam1507b, which shared 99 % 16S rRNA gene sequence identity, were isolated from terrestrial hot springs of the Uzon caldera on the Kamchatka peninsula. Cells of both strains were non-motile, regular cocci. Growth was observed between 55 and 85 degrees C, with an optimum at 65-70 degrees C (doubling time, 6.1 h), and at pH 4.5-7.5, with optimum growth at pH 5.5-6.0. The isolates were strictly anaerobic organotrophs and grew on a narrow spectrum of energy-rich substrates, such as beef extract, gelatin, peptone, pyruvate, sucrose and yeast extract, with yields above 10(7) cells ml(-1). Sulfate, sulfite, thiosulfate and nitrate added as potential electron acceptors did not stimulate growth when tested with peptone. H(2) at 100 % in the gas phase inhibited growth on peptone. Glycerol dibiphytanyl glycerol tetraethers (GDGTs) with zero to four cyclopentyl rings were present in the lipid fraction of isolate Kam940(T). The G+C content of the genomic DNA of strain Kam940(T) was 37 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolates were archaea of the phylum Crenarchaeota, only distantly related to the cultured members of the class Thermoprotei (no more than 89 % identity), and formed an independent lineage adjacent to the orders Desulfurococcales and Acidilobales and clustering only with uncultured clones from hot springs of Yellowstone National Park and Iceland as the closest relatives. On the basis of their phylogenetic position and novel phenotypic features, isolates Kam940(T) and Kam1507b are proposed to be assigned to a new genus and species, Fervidicoccus fontis gen. nov., sp. nov. The type strain of Fervidicoccus fontis is strain Kam940(T) (=DSM 19380(T) =VKM B-2539(T)). The phylogenetic data as well as phenotypic properties suggest that the novel crenarchaeotes form the basis of a new family, Fervidicoccaceae fam. nov., and order, Fervidicoccales ord. nov

  7. Bioleaching of metals from spent refinery petroleum catalyst using moderately thermophilic bacteria: effect of particle size.

    Science.gov (United States)

    Srichandan, Haragobinda; Singh, Sradhanjali; Pathak, Ashish; Kim, Dong-Jin; Lee, Seoung-Won; Heyes, Graeme

    2014-01-01

    The present work investigated the leaching potential of moderately thermophilic bacteria in the recovery of metals from spent petroleum catalyst of varying particle sizes. The batch bioleaching experiments were conducted by employing a mixed consortium of moderate thermophilic bacteria at 45°C and by using five different particle sizes (from 45 to >2000 μm) of acetone-washed spent catalyst. The elemental mapping by FESEM confirmed the presence of Al, Ni, V and Mo along with sulfur in the spent catalyst. During bioleaching, Ni (92-97%) and V (81-91%) were leached in higher concentrations, whereas leaching yields of Al (23-38%) were found to be lowest in all particle sizes investigated. Decreasing the particle size from >2000 μm to 45-106 μm caused an increase in leaching yields of metals during initial hours. However, the final metals leaching yields were almost independent of particle sizes of catalyst. Leaching kinetics was observed to follow the diffusion-controlled model showing the linearity more close than the chemical control. The results of the present study suggested that bioleaching using moderate thermophilic bacteria was highly effective in removing the metals from spent catalyst. Moreover, bioleaching can be conducted using spent catalyst of higher particle size (>2000 μm), thus saving the grinding cost and making process attractive for larger scale application.

  8. Phenols in anaerobic digestion processes and inhibition of ammonia oxidising bacteria (AOB) in soil

    International Nuclear Information System (INIS)

    Leven, Lotta; Nyberg, Karin; Korkea-aho, Lena; Schnuerer, Anna

    2006-01-01

    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 (EC 5 = 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 (EC 5 = 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Margaritis, A; Merchant, R; Yaguchi, M

    1983-01-01

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

  10. 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.

  11. Efficient Genome Editing of a Facultative Thermophile Using Mesophilic spCas9

    NARCIS (Netherlands)

    Mougiakos, Ioannis; Bosma, Elleke F.; Weenink, Koen; Vossen, Eric; Goijvaerts, Kirsten; Oost, van der John; Kranenburg, van Richard

    2017-01-01

    Well-developed genetic tools for thermophilic microorganisms are scarce, despite their industrial and scientific relevance. Whereas highly efficient CRISPR/Cas9-based genome editing is on the rise in prokaryotes, it has never been employed in a thermophile. Here, we apply Streptococcus pyogenes

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

    International Nuclear Information System (INIS)

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

    2002-01-01

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

  14. 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.

  15. Application of high rate, high temperature anaerobic digestion to fungal thermozyme hydrolysates from carbohydrate wastes.

    Science.gov (United States)

    Forbes, C; O'Reilly, C; McLaughlin, L; Gilleran, G; Tuohy, M; Colleran, E

    2009-05-01

    The objective of this study was to examine the feasibility of using a two-step, fully biological and sustainable strategy for the treatment of carbohydrate rich wastes. The primary step in this strategy involves the application of thermostable enzymes produced by the thermophilic, aerobic fungus, Talaromyces emersonii, to carbohydrate wastes producing a liquid hydrolysate discharged at elevated temperatures. To assess the potential of thermophilic treatment of this hydrolysate, a comparative study of thermophilic and mesophilic digestion of four sugar rich thermozyme hydrolysate waste streams was conducted by operating two high rate upflow anaerobic hybrid reactors (UAHR) at 37 degrees C (R1) and 55 degrees C (R2). The operational performance of both reactors was monitored from start-up by assessing COD removal efficiencies, volatile fatty acid (VFA) discharge and % methane of the biogas produced. Rapid start-up of both R1 and R2 was achieved on an influent composed of the typical sugar components of the organic fraction of municipal solid waste (OFMSW). Both reactors were subsequently challenged in terms of volumetric loading rate (VLR) and it was found that a VLR of 9 gCOD l(-1)d(-1) at a hydraulic retention time (HRT) of 1 day severely affected the thermophilic reactor with instability characterised by a build up of volatile fatty acid (VFA) intermediates in the effluent. The influent to both reactors was changed to a simple glucose and sucrose-based influent supplied at a VLR of 4.5 gCOD l(-1)d(-1) and HRT of 2 days prior to the introduction of thermozyme hydrolysates. Four unique thermozyme hydrolysates were subsequently supplied to the reactors, each for a period of 10 HRTs. The applied hydrolysates were derived from apple pulp, bread, carob powder and cardboard, all of which were successfully and comparably converted by both reactors. The % total carbohydrate removal by both reactors was monitored during the application of the sugar rich thermozyme

  16. Anaerobic biotransformation of estrogens

    International Nuclear Information System (INIS)

    Czajka, Cynthia P.; Londry, Kathleen L.

    2006-01-01

    Estrogens are important environmental contaminants that disrupt endocrine systems and feminize male fish. We investigated the potential for anaerobic biodegradation of the estrogens 17-α-ethynylestradiol (EE2) and 17-β-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 μg L -1 day -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-α-estradiol under all but nitrate-reducing conditions. Although E2 could be readily transformed to E1 and in many cases 17-α-estradiol under anaerobic conditions, the complete degradation of estrogens under these conditions was minimal, suggesting that they would accumulate in anoxic environments

  17. Genomic analysis of Melioribacter roseus, facultatively anaerobic organotrophic bacterium representing a novel deep lineage within Bacteriodetes/Chlorobi group.

    Directory of Open Access Journals (Sweden)

    Vitaly V Kadnikov

    Full Text Available Melioribacter roseus is a moderately thermophilic facultatively anaerobic organotrophic bacterium representing a novel deep branch within Bacteriodetes/Chlorobi group. To better understand the metabolic capabilities and possible ecological functions of M. roseus and get insights into the evolutionary history of this bacterial lineage, we sequenced the genome of the type strain P3M-2(T. A total of 2838 open reading frames was predicted from its 3.30 Mb genome. The whole proteome analysis supported phylum-level classification of M. roseus since most of the predicted proteins had closest matches in Bacteriodetes, Proteobacteria, Chlorobi, Firmicutes and deeply-branching bacterium Caldithrix abyssi, rather than in one particular phylum. Consistent with the ability of the bacterium to grow on complex carbohydrates, the genome analysis revealed more than one hundred glycoside hydrolases, glycoside transferases, polysaccharide lyases and carbohydrate esterases. The reconstructed central metabolism revealed pathways enabling the fermentation of complex organic substrates, as well as their complete oxidation through aerobic and anaerobic respiration. Genes encoding the photosynthetic and nitrogen-fixation machinery of green sulfur bacteria, as well as key enzymes of autotrophic carbon fixation pathways, were not identified. The M. roseus genome supports its affiliation to a novel phylum Ignavibateriae, representing the first step on the evolutionary pathway from heterotrophic ancestors of Bacteriodetes/Chlorobi group towards anaerobic photoautotrophic Chlorobi.

  18. (Hyper)thermophilic Enzymes: Production and Purification

    NARCIS (Netherlands)

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

    2014-01-01

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

  19. Enzyme activity screening of thermophilic bacteria isolated from Dusun Tua Hot Spring, Malaysia

    Science.gov (United States)

    Msarah, Marwan; Ibrahim, Izyanti; Aqma, Wan Syaidatul

    2018-04-01

    Thermophilic bacteria have biotechnological importance due to the availability of unique enzymes which are stable in extreme circumstances. The aim of this study includes to isolate thermophilic bacteria from hot spring and screen for important enzyme activities. Water samples from the Dusun Tua Hot Spring were collected and the physiochemical characterisation of water was measured. Eight thermophilic bacteria were isolated and determined to have at least three strong enzyme activity including protease, lipase, amylase, cellulase, pectinase and xylanase. The results showed that HuluC2 displayed all the enzyme activities and can be further studied.

  20. 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

  1. Kinetic study of thermophilic anaerobic digestion of solid wastes from potato processing

    International Nuclear Information System (INIS)

    Linke, Bernd

    2006-01-01

    Anaerobic treatment of solid wastes from potato processing was studied in completely stirred tank reactors (CSTR) at 55 o C. Special attention was paid to the effect of increased organic loading rate (OLR) on the biogas yield in long-term experiments. Both biogas yield and CH 4 in the biogas decreased with the increase in OLR. For OLR in the range of 0.8 gl -1 d -1 -3.4 gl -1 d -1 , biogas yield and CH 4 obtained were 0.85 l g -1 -0.65 l g -1 and 58%-50%, respectively. Biogas yield y as a function of maximum biogas yield y m , reaction rate constant k and HRT are described on the basis of a mass balance in a CSTR and a first order kinetic. The value of y m can be obtained from curve fitting or a simple batch test and k results from plotting y/(y m -y) against 1/OLR from long-term experiments. In the present study values for y m and k were obtained as 0.88 l g -1 and 0.089 d -1 , respectively. The simple model equations can apply for dimensioning completely stirred tank reactors (CSTR) digesting organic wastes from food processing industries, animal waste slurries or biogas crops

  2. Methane production by anaerobic digestion of algae. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Nyns, E.J.; Naveau, H.P.

    Methane is produced experimentally by anaerobic fermentation of algae, principally of species Hydrodictyon and Cladophora, grown in cooling water from nuclear power plants. The accumulation of fatty acids, by-products of fermentation, is found to have an inhibitory effect on methane production. Methods to remove fatty acids and stabilise the reaction are investigated. An economic analysis is presented using a financial model processor based on data from experimental digesters. The experimental work is described and the results are presented in an Appendix (in French). Seven relevant papers, of which two are in French are also annexed.

  3. Anaerobic hydrogen production from unhydrolyzed mushroom farm waste by indigenous microbiota.

    Science.gov (United States)

    Lin, Chiu-Yue; Lay, Chyi-How; Sung, I-Yuan; Sen, Biswarup; Chen, Chin-Chao

    2017-10-01

    The cultivation of mushrooms generates large amounts of waste polypropylene bags stuffed with wood flour and bacterial nutrients that makes the mushroom waste (MW) a potential feedstock for anaerobic bioH 2 fermentation. MW indigenous bacteria were enriched using thermophilic temperature (55°C) for use as the seed inoculum without any external seeding. The peak hydrogen production rate (6.84 mmol H 2 /L-d) was obtained with cultivation pH 8 and substrate concentration of 60 g MW/L in batch fermentation. Hydrogen production yield (HY) is pH and substrate concentration dependent with an HY decline occurring at pH and substrate concentration increasing from pH 8 to 10 and 60 to 80 g MW/L, respectively. The fermentation bioH 2 production from MW is in an acetate-type metabolic path. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  4. [Anaerobic bacteria isolated from patients with suspected anaerobic infections].

    Science.gov (United States)

    Ercis, Serpil; Tunçkanat, Ferda; Hasçelik, Gülşen

    2005-10-01

    The study involved 394 clinical samples sent to the Clinical Microbiology Laboratory of Hacettepe University Adult Hospital between January 1997 and May 2004 for anaerobic cultivation. Since multiple cultures from the same clinical samples of the same patient were excluded, the study was carried on 367 samples. The anaerobic cultures were performed in anaerobic jar using AnaeroGen kits (Oxoid, Basingstoke, U.K.) or GENbox (bioMérieux, Lyon, France). The isolates were identified by both classical methods and "BBL Crystal System" (Becton Dickinson, U.S.A.). While no growth was detected in 120 (32.7%) of the clinical samples studied, in 144 samples (39.2%) only aerobes, in 28 (7.6%) only anaerobes and in 75 (20.5%) of the samples both aerobes and anaerobes were isolated. The number of the anaerobic isolates was 217 from 103 samples with anaerobic growth. Of these 103 samples 15 showed single bacterial growth whereas in 88 samples multiple bacterial isolates were detected. Anaerobic isolates consisted of 92 Gram negative bacilli (Bacteroides spp. 50, Prevotella spp. 14, Porphyromonas spp. 10, Fusobacterium spp. 7, Tisierella spp. 2, unidentified 9), 57 Gram positive bacilli (Clostridium spp.17, Propionibacterium spp. 16, Lactobacillus spp. 8, Actinomyces spp. 5, Eubacterium spp. 2, Bifidobacterium adolescentis 1, Mobiluncus mulieris 1, unidentified nonspore forming rods 7), 61 Gram positive cocci (anaerobic cocci 44, microaerophilic cocci 17), and 7 Gram negative cocci (Veillonella spp.). In conclusion, in the samples studied with prediagnosis of anaerobic infection, Bacteroides spp. (23%) were the most common bacteria followed by anaerobic Gram positive cocci (20.3%) and Clostridium spp (7.8%).

  5. Supplement to thermophilic hydrolysis of liquid manures. Bilag til termofil hydrolyse af gylle

    Energy Technology Data Exchange (ETDEWEB)

    1990-07-01

    A supplement to ''Thermophilic hydrolysis of liquid manures'' which contains descriptions of testing methods and results for determining the influence of additives such as propionic acid or triolein on chemical reactions in connection with the decomposition of liquid manures under thermophilic conditions. (AB).

  6. Characteristics of residues from thermally treated anaerobic sludges

    International Nuclear Information System (INIS)

    Friedman, A.A.; Smith, J.E.; De Santis, J.; Ptak, T.; Ganley, R.C.

    1988-01-01

    Sludge management and disposal are probably the most difficult and expensive operations involved in wastewater treatment today. To minimize final disposal costs many waste treatment facilities practice some form of anaerobic digestion and dewatering to reduce the volume and offensiveness of their by-product sludges. One potential alternative for reducing sludge volumes consists of high temperature, partial oxidation of these previously digested sludges (PDS) and subsequent anaerobic biological conversion of resulting soluble organics to methane. This paper describes solids destruction, residue characteristics and biodegradability factors that should be considered in the design of liquid thermal treatment processes for the management of anaerobic sludges. To date only very limited information is available concerning the suitability of thermally treated PDS to serve as a substrate for the generation of methane. The primary objective of this research was to determine the feasibility of producing methane efficiently from the residual VSS in anaerobically digested sludges. Secondary goals were to establish the ''best'' conditions for thermal treatment for solubilizing PDS, to observe the effect of the soluble products on methanogenesis and to evaluate process sidestreams for dewaterability and anaerobic biodegradability

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

    African Journals Online (AJOL)

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

  8. [Application of anaerobic bacteria detection in oral and maxillofacial infection].

    Science.gov (United States)

    Bao, Zhen-ying; Lin, Qin; Meng, Yan-hong; He, Chun; Su, Jia-zeng; Peng, Xin

    2016-02-18

    To investigate the distribution and drug resistance of anaerobic bacteria in the patients with oral and maxillofacial infection. Aerobic and anaerobic bacteria cultures from 61 specimens of pus from the patients with oral and maxillofacial infection in the Department of Oral and Maxillofacial Surgery, Peking University School of Stomatology were identified. The culture type was evaluated by API 20A kit and drug resistance test was performed by Etest method. The clinical data and antibacterial agents for the treatment of the 61 cases were collected, and the final outcomes were recorded. The bacteria cultures were isolated from all the specimens, with aerobic bacteria only in 6 cases (9.8%), anaerobic bacteria only in 7 cases (11.5%), and both aerobic and anaerobic bacteria in 48 cases (78.7%). There were 55 infected cases (90.2%) with anaerobic bacteria, and 81 anaerobic bacteria stains were isolated. The highest bacteria isolation rate of Gram positive anaerobic bacteria could be found in Peptostreptococcus, Bifidobacterium and Pemphigus propionibacterium. No cefoxitin, amoxicillin/carat acid resistant strain was detected in the above three Gram positive anaerobic bacteria. The highest bacteria isolation rate of Gram negative anaerobic bacteria could be detected in Porphyromonas and Prevotella. No metronidazole, cefoxitin, amoxicillin/carat acid resistant strain was found in the two Gram negative anaerobic bacteria. In the study, 48 patients with oral and maxillofacial infection were treated according to the results of drug resistance testing, and the clinical cure rate was 81.3%. Mixed aerobic and anaerobic bacteria cultures are very common in most oral and maxillofacial infection patients. Anaerobic bacteria culture and drug resistance testing play an important role in clinical treatment.

  9. Clostridium thermocellum: adhesion and sporulation while adhered to cellulose and hemicellulose

    Energy Technology Data Exchange (ETDEWEB)

    Wiegel, J.; Dykstra, M.

    1984-01-01

    During growth in the presence of fibers composed of cellulose or hemicellulose, various strains of the thermophilic soil bacterium Clostridium thermocellum and several newly isolated thermophilic anaerobic soil bacteria adhered to the fibers. Attachment occurred via a fibrous ruthenium red-staining material. C. thermocellum sporulated while attached to the fibers when the pH dropped below 6.4. It is postulated that the attachment is involved in cellulose breakdown and that C. thermocellum gaines an advantage by remaining attached to its insoluble substrates when the environment is not suitable for rapid growth. The tendency to adhere to cellulose fibers was used in the purification of thermophilic cellulolytic anaerobes. 27 references, 7 figures.

  10. Anaerobic co-digestion of winery waste and waste activated sludge: assessment of process feasibility.

    Science.gov (United States)

    Da Ros, C; Cavinato, C; Cecchi, F; Bolzonella, D

    2014-01-01

    In this study the anaerobic co-digestion of wine lees together with waste activated sludge in mesophilic and thermophilic conditions was tested at pilot scale. Three organic loading rates (OLRs 2.8, 3.3 and 4.5 kgCOD/m(3)d) and hydraulic retention times (HRTs 21, 19 and 16 days) were applied to the reactors, in order to evaluate the best operational conditions for the maximization of the biogas yields. The addition of lee to sludge determined a higher biogas production: the best yield obtained was 0.40 Nm(3)biogas/kgCODfed. Because of the high presence of soluble chemical oxygen demand (COD) and polyphenols in wine lees, the best results in terms of yields and process stability were obtained when applying the lowest of the three organic loading rates tested together with mesophilic conditions.

  11. Fate of pathogens and micro-pollutants during organic wastes and by-products anaerobic digestion - a review; Etat des connaissances sur le devenir des germes pathogenes et des micropolluants au cours de la methanisation des dechets et sous-produits organiques

    Energy Technology Data Exchange (ETDEWEB)

    Couturier, Ch; Galtier, L

    1998-09-01

    Based on 300 scientific papers, the following bibliographical research deals with the fate of micro-pollutants (pathogens, heavy metals, organic pollutants) during anaerobic digestion. Different biological and chemical mechanisms allow organic compounds elimination, except from some Polycyclic Aromatic Hydrocarbons (PAHs) and heavy metals which are fixed to the solid biomass, permitting water contamination risks attenuation. Unlike mesophilic digestion, thermophilic digestion is a 'sanitation' process regarding pathogens elimination. However, mesophilic digestion offers an important reliability compared with competitive or complementary processes. In particular, energy recovery from anaerobic digestion allows temperature control and makes easier further sanitation heat treatments. In general, anaerobic digestion represents a tool which can be included in an organic waste treatment line assuming waste selection and good agricultural practices. Otherwise, sanitation problem is still badly handled by waste operators and constructors which have been consulted. Research orientations seem especially interesting in improving knowledge of real industrial processes performances. (author)

  12. 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.

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

    African Journals Online (AJOL)

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

  14. 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.

  15. [Conversion of acetic acid to methane by thermophiles

    Energy Technology Data Exchange (ETDEWEB)

    Zinder, S.H.

    1993-01-01

    The primary goal of this project is to obtain a better understanding of thermophilic microorganisms which convert acetic acid to CH[sub 4]. The previous funding period represents a departure from earlier research in this laboratory, which was more physiological and ecological. The present work is centered on the biochemistry of the thermophile Methanothrix sp. strain CALS-1. this organism presents a unique opportunity, with its purity and relatively rapid growth, to do comparative biochemical studies with the other major acetotrophic genus Methanosarcina. We previously found that Methanothrix is capable of using acetate at concentrations 100 fold lower than Methanosarcina. This finding suggests that there are significant differences in the pathways of methanogenesis from acetate in the two genera.

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

    Directory of Open Access Journals (Sweden)

    Karlsson Eva

    2007-03-01

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

  17. Kinetics of thermophilic acidogenesis of typical Brazilian sugarcane vinasse

    International Nuclear Information System (INIS)

    Koyama, Mirian Harumi; Araújo Júnior, Moacir Messias; Zaiat, Marcelo

    2016-01-01

    The kinetics of the acidogenic phase during anaerobic digestion of sugarcane vinasse in differential reactors containing immobilized cells was investigated. The maximum substrate conversion rate (r_m_a_x), substrate saturation constant (K_s) and constant of inhibition by excess substrate (K_i_s) were determined using vinasse with and without pH adjustment. Simulation and scaling-up of a thermophilic-hydrogen production system were performed. The r_m_a_x values obtained at different pH were similar and near 0.9 mg-Total carbohydrates g-VS"−"1 h"−"1. The K_s obtained from the system without pH adjustment was 10,762.3 mg-Total carbohydrates L"−"1 (i.e., 2.5 times higher than the system with pH adjustment). No inhibition by excess substrate was achieved in the system without pH adjustment, indicating that sugarcane vinasse can be used to produce hydrogen without input costs. The simulation revealed that hydrogen production is a sensitive process that requires careful balancing of various operational parameters. The payback for the investment in system implementation is 4.4 years. - Highlights: • Sugarcane vinasse can be used to produce hydrogen without pH adjustment. • Excess substrate inhibition was observed when vinasse with pH adjusted was used. • A careful balancing of operational conditions is required to produce hydrogen. • The payback for the investment in system implementation is four years.

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

    Science.gov (United States)

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

    2006-03-01

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

  19. Combining high-rate aerobic wastewater treatment with anaerobic digestion of waste activated sludge at a pulp and paper mill.

    Science.gov (United States)

    Magnusson, Björn; Ekstrand, Eva-Maria; Karlsson, Anna; Ejlertsson, Jörgen

    2018-05-01

    The activated sludge process within the pulp and paper industry is generally run to minimize the production of waste activated sludge (WAS), leading to high electricity costs from aeration and relatively large basin volumes. In this study, a pilot-scale activated sludge process was run to evaluate the concept of treating the wastewater at high rate with a low sludge age. Two 150 L containers were used, one for aeration and one for sedimentation and sludge return. The hydraulic retention time was decreased from 24 hours to 7 hours, and the sludge age was lowered from 12 days to 2-4 days. The methane potential of the WAS was evaluated using batch tests, as well as continuous anaerobic digestion (AD) in 4 L reactors in mesophilic and thermophilic conditions. Wastewater treatment capacity was increased almost four-fold at maintained degradation efficiency. The lower sludge age greatly improved the methane potential of the WAS in batch tests, reaching 170 NmL CH 4 /g VS at a sludge age of 2 days. In addition, the continuous AD showed a higher methane production at thermophilic conditions. Thus, the combination of high-rate wastewater treatment and AD of WAS is a promising option for the pulp and paper industry.

  20. Exceptional thermal stability and organic solvent tolerance of an esterase expressed from a thermophilic host

    DEFF Research Database (Denmark)

    Mei, Yuxia; Peng, Nan; Zhao, Shumiao

    2012-01-01

    , giving SisEstA. Upon Escherichia coli expression, only the thioredoxin-tagged EstA recombinant protein was soluble. The fusion protein was then purified, and removing the protein tag yielded EcSisEstA. Both forms of the thermophilic EstA enzyme were characterized. We found that SisEstA formed dimer...... that of EcSisEstA at 90°C. This indicated that thermophilic enzymes yielded from homologous expression should be better biocatalysts than those obtained from mesophilic expression.......A protein expression system recently developed for the thermophilic crenarchaeon Sulfolobus islandicus was employed to produce recombinant protein for EstA, a thermophilic esterase encoded in the same organism. Large amounts of protein were readily obtained by an affinity protein purification...

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

    Science.gov (United States)

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

    2013-01-01

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

  2. Concomitant production of cellulase and xylanase by thermophilic mould Sporotrichum thermophile in solid state fermentation and their applicability in bread making.

    Science.gov (United States)

    Bala, Anju; Singh, Bijender

    2017-06-01

    Sporotrichum thermophile BJAMDU5 secreted high titres of xylanolytic and cellulolytic enzymes in solid state fermentation using mixture of wheat straw and cotton oil cake (ratio 1:1) at 45 °C, pH 5.0 after 72 h inoculated with 2.9 × 10 7  CFU/mL conidiospores. Supplementation of solid medium with lactose and ammonium sulphate further enhanced the production of hydrolytic enzymes. Among different surfactants studied, Tween 80 enhanced the production of all enzymes [3455 U/g DMR (dry mouldy residue), 879.26 U/g DMR, 976.28 U/g DMR and 35.10 U/g DMR for xylanase, CMCase (Carboxymethylcellulase), FPase (Filter paper activity) and β-glucosidase, respectively] as compared to other surfactants. Recycling of solid substrate reduced the production of all these enzymes after second cycle. End products analysis by TLC showed the ability of hydrolytic enzymes of S. thermophile to liberate monomeric (xylose and glucose) as well as oligomeric (xylobiose, cellobiose and higher ones) sugars. Supplementation of enzyme resulted in improved nutritional properties of the bread. Formation of oligomeric sugars by xylanase enzyme of S. thermophile BJAMDU5 make it a good candidate in food industry.

  3. A Unique Autothermal Thermophilic Aerobic Digestion Process Showing a Dynamic Transition of Physicochemical and Bacterial Characteristics from the Mesophilic to the Thermophilic Phase.

    Science.gov (United States)

    Tashiro, Yukihiro; Kanda, Kosuke; Asakura, Yuya; Kii, Toshihiko; Cheng, Huijun; Poudel, Pramod; Okugawa, Yuki; Tashiro, Kosuke; Sakai, Kenji

    2018-03-15

    A unique autothermal thermophilic aerobic digestion (ATAD) process has been used to convert human excreta to liquid fertilizer in Japan. This study investigated the changes in physicochemical and bacterial community characteristics during the full-scale ATAD process operated for approximately 3 weeks in 2 different years. After initiating simultaneous aeration and mixing using an air-inducing circulator (aerator), the temperature autothermally increased rapidly in the first 1 to 2 days with exhaustive oxygen consumption, leading to a drastic decrease and gradual increase in oxidation-reduction potential in the first 2 days, reached >50°C in the middle 4 to 6 days, and remained steady in the final phase. Volatile fatty acids were rapidly consumed and diminished in the first 2 days, whereas the ammonia nitrogen concentration was relatively stable during the process, despite a gradual pH increase to 9.3. Principal-coordinate analysis of 16S rRNA gene amplicons using next-generation sequencing divided the bacterial community structures into distinct clusters corresponding to three phases, and they were similar in the final phase in both years despite different transitions in the middle phase. The predominant phyla (closest species, dominancy) in the initial, middle, and final phases were Proteobacteria ( Arcobacter trophiarum , 19 to 43%; Acinetobacter towneri , 6.3 to 30%), Bacteroidetes ( Moheibacter sediminis , 43 to 54%), and Firmicutes ( Thermaerobacter composti , 11 to 28%; Heliorestis baculata , 2.1 to 16%), respectively. Two predominant operational taxonomic units (OTUs) in the final phase showed very low similarities to the closest species, indicating that the process is unique compared with previously published ones. This unique process with three distinctive phases would be caused by the aerator with complete aeration. IMPORTANCE Although the autothermal thermophilic aerobic digestion (ATAD) process has several advantages, such as a high degradation

  4. Molecular characterization of thermophilic Campylobacter species ...

    African Journals Online (AJOL)

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

  5. Towards a sustainable paradigm of waste-to-energy process: Enhanced anaerobic digestion of sludge with woody biochar

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Yanwen; Linville, Jessica L.; Ignacio-de Leon, Patricia Anne A.; Schoene, Robin P.; Urgun-Demirtas, Meltem

    2016-11-01

    This study presents an integrated waste-to-energy process, using two waste streams, sludge generated from the municipal wastewater treatment plants (WWTPs) and biochar generated from the biomass gasification systems, to produce fungible biomethane and nutrient-rich digestate with fertilizer value. Two woody biochar, namely pinewood (PBC) and white oak biochar (WOBC) were used as additives during anaerobic digestion (AD) of WWTP sludge to enhance methane production at mesophilic and thermophilic temperatures. The PBC and WOBC have porous structure, large surface area and desirable chemical properties to be used as AD amendment material to sequester CO2 from biogas in the digester. The biochar-amended digesters achieved average methane content in biogas of up to 92.3% and 79.0%, corresponding to CO2 sequestration by up to 66.2% and 32.4% during mesophilic and thermophilic AD, respectively. Biochar addition enhanced process stability by increasing the alkalinity, but inhibitory effects were observed at high dosage. It also alleviated free ammonia inhibition by up to 10.5%. The biochar-amended digesters generated digestate rich in macro- and micronutrients including K (up to 300 m/L), Ca (up to 750 mg/L), Mg (up to 1800 mg/L) and Fe (up to 390 mg/L), making biochar-amended digestate a potential alternative used as agricultural lime fertilizer.

  6. Novel thermophilic hemicellulases for the conversion of lignocellulose for second generation biorefineries.

    Science.gov (United States)

    Cobucci-Ponzano, Beatrice; Strazzulli, Andrea; Iacono, Roberta; Masturzo, Giuseppe; Giglio, Rosa; Rossi, Mosè; Moracci, Marco

    2015-10-01

    The biotransformation of lignocellulose biomasses into fermentable sugars is a very complex procedure including, as one of the most critical steps, the (hemi) cellulose hydrolysis by specific enzymatic cocktails. We explored here, the potential of stable glycoside hydrolases from thermophilic organisms, so far not used in commercial enzymatic preparations, for the conversion of glucuronoxylan, the major hemicellulose of several energy crops. Searches in the genomes of thermophilic bacteria led to the identification, efficient production, and detailed characterization of novel xylanase and α-glucuronidase from Alicyclobacillus acidocaldarius (GH10-XA and GH67-GA, respectively) and a α-glucuronidase from Caldicellulosiruptor saccharolyticus (GH67-GC). Remarkably, GH10-XA, if compared to other thermophilic xylanases from this family, coupled good specificity on beechwood xylan and the best stability at 65 °C (3.5 days). In addition, GH67-GC was the most stable α-glucuronidases from this family and the first able to hydrolyse both aldouronic acid and aryl-α-glucuronic acid substrates. These enzymes, led to the very efficient hydrolysis of beechwood xylan by using 7- to 9-fold less protein (concentrations thermophilic enzymes. In addition, remarkably, together with a thermophilic β-xylosidase, they catalyzed the production of xylose from the smart cooking pre-treated biomass of one of the most promising energy crops for second generation biorefineries. We demonstrated that search by the CAZy Data Bank of currently available genomes and detailed enzymatic characterization of recombinant enzymes allow the identification of glycoside hydrolases with novel and interesting properties and applications. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. 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.

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

    OpenAIRE

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

    2015-01-01

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

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

    KAUST Repository

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

    2012-01-01

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

  10. 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.

  11. Aspergillus fumigatus and other thermophilic fungi in nests of wetland birds.

    Science.gov (United States)

    Korniłłowicz-Kowalska, Teresa; Kitowski, Ignacy

    2013-02-01

    A study was performed on the numbers and species diversity of thermophilic fungi (growing at 45 °C in vitro) in 38 nests of 9 species of wetland birds, taking into account the physicochemical properties of the nests and the bird species. It was found that in nests with the maximum weight (nests of Mute Swan), the number and diversity of thermophilic fungi were significantly greater than in other nests, with lower weight. The diversity of the thermophilic biota was positively correlated with the individual mass of bird and with the level of phosphorus in the nests. The dominant species within the mycobiota under study was Aspergillus fumigatus which inhabited 95% of the nests under study, with average frequency of ca. 650 cfu g(-1) of dry mass of the nest material. In a majority of the nests studied (nests of 7 bird species), the share of A. fumigatus exceeded 50% of the total fungi growing at 45 °C. Significantly higher frequencies of the fungal species were characteristic of the nests of small and medium-sized piscivorous species, compared with the other bird species. The number of A. fumigatus increased with increase in the moisture level of the nests, whereas the frequency of occurrence of that opportunistic pathogen, opposite to the general frequency of thermophilic mycobiota, was negatively correlated with the level of phosphorus in the nest material, and with the body mass and length of the birds. The authors indicate the causes of varied growth of thermophilic fungi in nests of wetland birds and, in particular, present a discussion of the causes of accumulation of A. fumigatus, the related threats to the birds, and its role as a source of transmission in the epidemiological chain of aspergillosis.

  12. Fate of pathogens and micro-pollutants during organic wastes and by-products anaerobic digestion - a review; Etat des connaissances sur le devenir des germes pathogenes et des micropolluants au cours de la methanisation des dechets et sous-produits organiques

    Energy Technology Data Exchange (ETDEWEB)

    Couturier, Ch.; Galtier, L.

    1998-09-01

    Based on 300 scientific papers, the following bibliographical research deals with the fate of micro-pollutants (pathogens, heavy metals, organic pollutants) during anaerobic digestion. Different biological and chemical mechanisms allow organic compounds elimination, except from some Polycyclic Aromatic Hydrocarbons (PAHs) and heavy metals which are fixed to the solid biomass, permitting water contamination risks attenuation. Unlike mesophilic digestion, thermophilic digestion is a 'sanitation' process regarding pathogens elimination. However, mesophilic digestion offers an important reliability compared with competitive or complementary processes. In particular, energy recovery from anaerobic digestion allows temperature control and makes easier further sanitation heat treatments. In general, anaerobic digestion represents a tool which can be included in an organic waste treatment line assuming waste selection and good agricultural practices. Otherwise, sanitation problem is still badly handled by waste operators and constructors which have been consulted. Research orientations seem especially interesting in improving knowledge of real industrial processes performances. (author)

  13. ANAEROBIC BIOREMEDIATION OF PAH-CONTAMINATED SOIL: ASSESSMENT OF THE DEGRADATION OF CONTAMINANTS AND BIOGAS PRODUCTION UNDER THERMOPHILIC AND MESOPHILIC CONDITIONS

    Czech Academy of Sciences Publication Activity Database

    Sayara, T.; Čvančarová, Monika; Cajthaml, Tomáš; Sarra, M.; Sánchez, A.

    2015-01-01

    Roč. 14, č. 1 (2015), s. 153-165 ISSN 1582-9596 R&D Projects: GA ČR GA525/09/1058 Institutional support: RVO:61388971 Keywords : anaerobic digestion * central composite design * PAH-contaminated soil Subject RIV: EE - Microbiology, Virology Impact factor: 1.008, year: 2015

  14. A novel enzymatic system against oxidative stress in the thermophilic hydrogen-oxidizing bacterium Hydrogenobacter thermophilus.

    Directory of Open Access Journals (Sweden)

    Yuya Sato

    Full Text Available Rubrerythrin (Rbr is a non-heme iron protein composed of two distinctive domains and functions as a peroxidase in anaerobic organisms. A novel Rbr-like protein, ferriperoxin (Fpx, was identified in Hydrogenobacter thermophilus and was found not to possess the rubredoxin-like domain that is present in typical Rbrs. Although this protein is widely distributed among aerobic organisms, its function remains unknown. In this study, Fpx exhibited ferredoxin:NADPH oxidoreductase (FNR-dependent peroxidase activity and reduced both hydrogen peroxide (H(2O(2 and organic hydroperoxide in the presence of NADPH and FNR as electron donors. The calculated K(m and V(max values of Fpx for organic hydroperoxides were comparable to that for H(2O(2, demonstrating a multiple reactivity of Fpx towards hydroperoxides. An fpx gene disruptant was unable to grow under aerobic conditions, whereas its growth profiles were comparable to those of the wild-type strain under anaerobic and microaerobic conditions, clearly indicating the indispensability of Fpx as an antioxidant of H. thermophilus in aerobic environments. Structural analysis suggested that domain-swapping occurs in Fpx, and this domain-swapped structure is well conserved among thermophiles, implying the importance of structural stability of domain-swapped conformation for thermal environments. In addition, Fpx was located on a deep branch of the phylogenetic tree of Rbr and Rbr-like proteins. This finding, taken together with the wide distribution of Fpx among Bacteria and Archaea, suggests that Fpx is an ancestral type of Rbr homolog that functions as an essential antioxidant and may be part of an ancestral peroxide-detoxification system.

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

    Directory of Open Access Journals (Sweden)

    Judit Ribera

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

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

    Science.gov (United States)

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

    2017-01-01

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

  17. Stable isotope probing of acetate fed anaerobic batch incubations shows a partial resistance of acetoclastic methanogenesis catalyzed by Methanosarcina to sudden increase of ammonia level.

    Science.gov (United States)

    Hao, Liping; Lü, Fan; Mazéas, Laurent; Desmond-Le Quéméner, Elie; Madigou, Céline; Guenne, Angéline; Shao, Liming; Bouchez, Théodore; He, Pinjing

    2015-02-01

    Ammonia inhibition represents a major operational issue for anaerobic digestion. In order to refine our understanding of the terminal catabolic steps in thermophilic anaerobic digestion under ammonia stress, we studied batch thermophilic acetate fed experiments at low (0.26 g L(-1)) and high (7.00 g L(-1)) Total Ammonia Nitrogen concentrations (TAN). Although methane production started immediately for all incubations and resulted in methane yields close to stoichiometric expectations, a 62-72% decrease of methanogenic rate was observed throughout the incubation at 7.00 g L(-1) of TAN compared to 0.26 g L(-1). Stable Isotope Probing analysis of active microbial communities in (13)C-acetate fed experiments coupled to automated ribosomal intergenic spacer analysis and 16S rDNA pyrotag sequencing confirmed that microbial communities were similar for both TAN conditions. At both TAN levels, the (13)C-labeled bacterial community was mainly affiliated to Clostridia-relatives, with OPB54 bacteria being the most abundant sequence in the heavy DNA 16S rDNA pyrotag library. Sequences closely related to Methanosarcina thermophila were also abundantly retrieved in the heavy DNA fractions, showing that this methanogen was still actively assimilating labeled carbon from acetate at free ammonia nitrogen concentrations up to 916 mg L(-1). Stable isotopic signature analysis of biogas, measured in unlabeled acetate fed experiments that were conducted in parallel, confirmed that acetoclastic methanogenic pathway was dominant at both ammonia concentrations. Our work demonstrates that, besides the syntrophic acetate oxidation pathway, acetoclastic methanogenesis catalyzed by Methanosarcina can also play a major role in methane production at high ammonia levels. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Genetic Tools and Techniques for Recombinant Expression in Thermophilic Bacillaceae

    Directory of Open Access Journals (Sweden)

    Eivind B. Drejer

    2018-05-01

    Full Text Available Although Escherichia coli and Bacillus subtilis are the most prominent bacterial hosts for recombinant protein production by far, additional species are being explored as alternatives for production of difficult-to-express proteins. In particular, for thermostable proteins, there is a need for hosts able to properly synthesize, fold, and excrete these in high yields, and thermophilic Bacillaceae represent one potentially interesting group of microorganisms for such purposes. A number of thermophilic Bacillaceae including B. methanolicus, B. coagulans, B. smithii, B. licheniformis, Geobacillus thermoglucosidasius, G. kaustophilus, and G. stearothermophilus are investigated concerning physiology, genomics, genetic tools, and technologies, altogether paving the way for their utilization as hosts for recombinant production of thermostable and other difficult-to-express proteins. Moreover, recent successful deployments of CRISPR/Cas9 in several of these species have accelerated the progress in their metabolic engineering, which should increase their attractiveness for future industrial-scale production of proteins. This review describes the biology of thermophilic Bacillaceae and in particular focuses on genetic tools and methods enabling use of these organisms as hosts for recombinant protein production.

  19. Anaerobic Digestion: Process

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Batstone, Damien J.

    2011-01-01

    Organic waste may degrade anaerobically in nature as well as in engineered systems. The latter is called anaerobic digestion or biogasification. Anaerobic digestion produces two main outputs: An energy-rich gas called biogas and an effluent. The effluent, which may be a solid as well as liquid...... 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...

  20. Molecular diversity of thermophilic bacteria isolated from Pasinler hot spring (Erzurum, Turkey)

    OpenAIRE

    ADIGÜZEL, Ahmet; İNAN, Kadriye; ŞAHİN, Fikrettin; ARASOĞLU, Tulin; GÜLLÜCE, Medine

    2011-01-01

    The present study was conducted to determine the phenotypic and genotypic characterization of thermophilic bacteria isolated from Pasinler hot spring, Erzurum, Turkey. Fatty acid profiles, BOX PCR fingerprints, and 16S rDNA sequence data were used for the phenotypic and genotypic characterization of thermophilic bacteria. Totally 9 different bacterial strains were selected based on morphological, physiological, and biochemical tests. These strains were characterized by molecular tests includi...

  1. Long-term effects of operating temperature and sulphate addition on the methanogenic community structure of anaerobic hybrid reactors.

    Science.gov (United States)

    Pender, Seán; Toomey, Margaret; Carton, Micheál; Eardly, Dónal; Patching, John W; Colleran, Emer; O'Flaherty, Vincent

    2004-02-01

    The diversity, population dynamics, and activity profiles of methanogens in anaerobic granular sludges from two anaerobic hybrid reactors treating a molasses wastewater both mesophilically (37 degrees C) and thermophilically (55 degrees C) during a 1081 day trial were determined. The influent to one of the reactors was supplemented with sulphate, after an acclimation period of 112 days, to determine the effect of competition with sulphate-reducing bacteria on the methanogenic community structure. Sludge samples were removed from the reactors at intervals throughout the operational period and examined by amplified ribosomal DNA (rDNA) restriction analysis (ARDRA) and partial sequencing of 16S rRNA genes. In total, 18 operational taxonomic units (OTUs) were identified, 12 of which were sequenced. The methanogenic communities in both reactors changed during the operational period. The seed sludge and the reactor biomass sampled during mesophilic operation, both in the presence and absence of sulphate, was characterised by a predominance of Methanosaeta spp. Following temperature elevation, the dominant methanogenic sequences detected in the non-sulphate supplemented reactor were closely related to Methanocorpusculum parvum. By contrast, the dominant OTUs detected in the sulphate-supplemented reactor upon temperature increase were related to the hydrogen-utilising methanogen, Methanobacterium thermoautotrophicum. The observed methanogenic community structure in the reactors correlated with the operational performance of the reactors during the trial and with physiological measurements of the reactor biomass. Both reactors achieved chemical oxygen demand (COD) removal efficiencies of over 90% during mesophilic operation, with or without sulphate supplementation. During thermophilic operation, the presence of sulphate resulted in decreased reactor performance (effluent acetate concentrations of >3000 mg/l and biogas methane content of acetate at 55 degrees C was

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

    OpenAIRE

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

    2012-01-01

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

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

    African Journals Online (AJOL)

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

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

    Science.gov (United States)

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

    2015-06-01

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

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

    Directory of Open Access Journals (Sweden)

    Tarik Aanniz

    2015-06-01

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

  6. PENGOLAHAN LIMBAH CAIR INDUSTRI FARMASI FORMULASI DENGAN METODE ANAEROB-AEROB DAN ANAEROB-KOAGULASI

    OpenAIRE

    Farida Crisnaningtyas; Hanny Vistanty

    2016-01-01

    Studi ini membahas mengenai pengolahan limbah cair industri farmasi dalam skala laboratorium dengan menggunakan konsep anaerob-kimia-fisika dan anaerob-aerob. Proses anaerob dilakukan dengan menggunakan reaktor Upflow Anaerobic Sludge Bed reactor (UASBr) pada kisaran OLR (Organic Loading Rate) 0,5 – 2 kg COD/m3hari, yang didahului dengan proses aklimatisasi menggunakan substrat gula. Proses anaerob mampu memberikan efisiensi penurunan COD hingga 74%. Keluaran dari proses anaerob diolah lebih ...

  7. 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.

  8. Widespread disulfide bonding in proteins from thermophilic archaea.

    Science.gov (United States)

    Jorda, Julien; Yeates, Todd O

    2011-01-01

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

  9. Evolvability of thermophilic proteins from archaea and bacteria.

    Science.gov (United States)

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

    2013-07-16

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

  10. Anaerobes in pleuropulmonary infections

    Directory of Open Access Journals (Sweden)

    De A

    2002-01-01

    Full Text Available A total of 76 anaerobes and 122 aerobes were isolated from 100 patients with pleuropulmonary infections, e.g. empyema (64, pleural effusion (19 and lung abscess (13. In 14% of the patients, only anaerobes were recovered, while a mixture of aerobes and anaerobes was encountered in 58%. From all cases of lung abscess, anaerobic bacteria were isolated, alone (04 or along with aerobic bacteria (13. From empyema and pleural effusion cases, 65.6% and 68.4% anaerobes were recovered respectively. Amongst anaerobes, gram negative anaerobic bacilli predominated (Prevotella melaninogenicus 16, Fusobacterium spp. 10, Bacteroides spp. 9, followed by gram positive anaerobic cocci (Peptostreptococcus spp. 31. Coliform bacteria (45 and Pseudomonas aeruginosa (42 were the predominant aerobic isolates.

  11. Insight into glycoside hydrolases for debranched xylan degradation from extremely thermophilic bacterium Caldicellulosiruptor lactoaceticus.

    Directory of Open Access Journals (Sweden)

    Xiaojing Jia

    Full Text Available Caldicellulosiruptor lactoaceticus 6A, an anaerobic and extremely thermophilic bacterium, uses natural xylan as carbon source. The encoded genes of C. lactoaceticus 6A for glycoside hydrolase (GH provide a platform for xylan degradation. The GH family 10 xylanase (Xyn10A and GH67 α-glucuronidase (Agu67A from C. lactoaceticus 6A were heterologously expressed, purified and characterized. Both Xyn10A and Agu67A are predicted as intracellular enzymes as no signal peptides identified. Xyn10A and Agu67A had molecular weight of 47.0 kDa and 80.0 kDa respectively as determined by SDS-PAGE, while both appeared as homodimer when analyzed by gel filtration. Xyn10A displayed the highest activity at 80 °C and pH 6.5, as 75 °C and pH 6.5 for Agu67A. Xyn10A had good stability at 75 °C, 80 °C, and pH 4.5-8.5, respectively, and was sensitive to various metal ions and reagents. Xyn10A possessed hydrolytic activity towards xylo-oligosaccharides (XOs and beechwood xylan. At optimum conditions, the specific activity of Xyn10A was 44.6 IU/mg with beechwood xylan as substrate, and liberated branched XOs, xylobiose, and xylose. Agu67A was active on branched XOs with methyl-glucuronic acids (MeGlcA sub-chains, and primarily generated XOs equivalents and MeGlcA. The specific activity of Agu67A was 1.3 IU/mg with aldobiouronic acid as substrate. The synergistic action of Xyn10A and Agu67A was observed with MeGlcA branched XOs and xylan as substrates, both backbone and branched chain of substrates were degraded, and liberated xylose, xylobiose, and MeGlcA. The synergism of Xyn10A and Agu67A provided not only a thermophilic method for natural xylan degradation, but also insight into the mechanisms for xylan utilization of C. lactoaceticus.

  12. New Strategy for a Suitable Fast Stabilization of the Biomethanization Performance

    Science.gov (United States)

    Fernández-Güelfo, L. A.; Álvarez-Gallego, C. J.; Sales Márquez, D.; Romero García, L. I.

    2012-01-01

    The start-up strategies for thermophilic anaerobic reactors usually consist of an initial mesophilic stage (35°C), with an approximate duration of 185 days, and a subsequent thermophilic stage (55°C), which normally requires around 60 days to achieve the system stabilizatio. During the first 8–10 days of the mesophilic stage, the reactor is not fed so that the inoculum, which is generally a mesophilic anaerobic sludge, may be adapted to the organic solid waste. Between mesophilic and thermophilic conditions the reactor is still not fed in an effort to prevent possible imbalances in the proces. As a consequence, the start-up and stabilization of the biomethanization performance described in the literature require, at least, around 245 days. In this sense, a new strategy for the start-up and stabilization phases is presented in this study. This approach allows an important reduction in the overall time necessary for these stages in an anaerobic continuous stirred tank reactor (CSTR) operated at thermophilic-dry conditions for treating the organic fraction of the municipal solid waste (OFMSW): 60 days versus 245 days of conventional strategies. The new strategy uses modified SEBAC technology to adapt an inoculum to the OFMSW and the operational conditions prior to seeding the CSTR. PMID:23193374

  13. Occurrence and Detection of Thermoanaerobacterium and Thermoanaerobacter in Canned Food

    Directory of Open Access Journals (Sweden)

    Christian Dotzauer

    2002-01-01

    Full Text Available In order to determine the reason for loss of vacuum in canned food, obligately anaerobic, spore forming thermophilic organisms were isolated from shelf-stable canned food containing vegetables, noodles and potatoes as main ingredients. Thermophilic bacteria from 44 canned food samples that had been stored under anaerobic conditions at 37 °C for at least 7 days were isolated. In addition, organic fertilizer used for the cultivation of some of the foods’ ingredients was examined and anaerobic, thermophilic bacteria could also be isolated from this source. Identification of bacterial strains was carried out by partial and complete 16S-rRNA-gene sequencing. Some of the obtained gene sequences showed a high level of similarity to existing 16S-rRNA gene sequences towards strains of the genera Thermoanaerobacter, Thermoanaerobium and Thermoanaerobacterium respectively, which have not yet been reported to be of importance as food spoilers. In the course of identification of these thermophilic bacteria we developed genera specific PCR-based approaches for detecting isolates belonging to the genera Thermoanaeroacterium and Thermoanaerobacter. Direct capturing of free DNA from contaminated samples using oligonucleotides coupled with paramagentic beads allowed the reduction of the detection time to six hours with a lower limit of 104 cells/mL.

  14. New Strategy for a Suitable Fast Stabilization of the Biomethanization Performance

    Directory of Open Access Journals (Sweden)

    L. A. Fernández-Güelfo

    2012-01-01

    Full Text Available The start-up strategies for thermophilic anaerobic reactors usually consist of an initial mesophilic stage (35°C, with an approximate duration of 185 days, and a subsequent thermophilic stage (55°C, which normally requires around 60 days to achieve the system stabilizatio. During the first 8–10 days of the mesophilic stage, the reactor is not fed so that the inoculum, which is generally a mesophilic anaerobic sludge, may be adapted to the organic solid waste. Between mesophilic and thermophilic conditions the reactor is still not fed in an effort to prevent possible imbalances in the proces. As a consequence, the start-up and stabilization of the biomethanization performance described in the literature require, at least, around 245 days. In this sense, a new strategy for the start-up and stabilization phases is presented in this study. This approach allows an important reduction in the overall time necessary for these stages in an anaerobic continuous stirred tank reactor (CSTR operated at thermophilic-dry conditions for treating the organic fraction of the municipal solid waste (OFMSW: 60 days versus 245 days of conventional strategies. The new strategy uses modified SEBAC technology to adapt an inoculum to the OFMSW and the operational conditions prior to seeding the CSTR.

  15. Growth of the facultative anaerobe Shewanella putrefaciens by elemental sulfur reduction

    Science.gov (United States)

    Moser, D. P.; Nealson, K. H.

    1996-01-01

    The growth of bacteria by dissimilatory elemental sulfur reduction is generally associated with obligate anaerobes and thermophiles in particular. Here we describe the sulfur-dependent growth of the facultatively anaerobic mesophile Shewanella putrefaciens. Six of nine representative S. putrefaciens isolates from a variety of environments proved able to grow by sulfur reduction, and strain MR-1 was chosen for further study. Growth was monitored in a minimal medium (usually with 0.05% Casamino Acids added as a growth stimulant) containing 30 mM lactate and limiting concentrations of elemental sulfur. When mechanisms were provided for the removal of the metabolic end product, H2S, measurable growth was obtained at sulfur concentrations of from 2 to 30 mM. Initial doubling times were ca. 1.5 h and substrate independent over the range of sulfur concentrations tested. In the cultures with the highest sulfur concentrations, cell numbers increased by greater than 400-fold after 48 h, reaching a maximum density of 6.8 x 10(8) cells ml-1. Yields were determined as total cell carbon and ranged from 1.7 to 5.9 g of C mol of S(0) consumed-1 in the presence of the amino acid supplement and from 0.9 to 3.4 g of C mol of S(0-1) in its absence. Several lines of evidence indicate that cell-to-sulfur contact is not required for growth. Approaches for the culture of sulfur-metabolizing bacteria and potential ecological implications of sulfur reduction in Shewanella-like heterotrophs are discussed.

  16. Effects of sludge inoculum and organic feedstock on active microbial communities and methane yield during anaerobic digestion

    Directory of Open Access Journals (Sweden)

    David eWilkins

    2015-10-01

    Full Text Available Anaerobic digestion (AD is a widespread microbial technology used to treat organic waste and recover energy in the form of methane (biogas. While most AD systems have been designed to treat a single input, mixtures of digester sludge and solid organic waste are emerging as a means to improve efficiency and methane yield. We examined laboratory anaerobic cultures of AD sludge from two sources amended with food waste, xylose, and xylan at mesophilic temperatures, and with cellulose at meso- and thermophilic temperatures, to determine whether and how the inoculum and substrate affect biogas yield and community composition. All substrate and inoculum combinations yielded methane, with food waste most productive by mass. Pyrosequencing of transcribed bacterial and archaeal 16S rRNA showed that community composition varied across substrates and inocula, with differing ratios of hydrogenotrophic/acetoclastic methanogenic archaea associated with syntrophic partners. While communities did not cluster by either inoculum or substrate, additional sequencing of the bacterial 16S rRNA gene in the source sludge revealed that the bacterial communities were influenced by their inoculum. These results suggest that complete and efficient AD systems could potentially be assembled from different microbial inocula and consist of taxonomically diverse communities that nevertheless perform similar functions.

  17. Indigenous microbial capability in solid manure residues to start-up solid-phase anaerobic digesters.

    Science.gov (United States)

    Yap, S D; Astals, S; Jensen, P D; Batstone, D J; Tait, S

    2017-06-01

    Batch solid-phase anaerobic digestion is a technology for sustainable on-farm treatment of solid residues, but is an emerging technology that is yet to be optimised with respect to start-up and inoculation. In the present study, spent bedding from two piggeries (site A and B) were batch digested at total solids (TS) concentration of 5, 10 and 20% at mesophilic (37°C) and thermophilic (55°C) temperatures, without adding an external inoculum. The results showed that the indigenous microbial community present in spent bedding was able to recover the full methane potential of the bedding (140±5 and 227±6L CH 4 kgVS fed -1 for site A and B, respectively), but longer treatment times were required than for digestion with an added external inoculum. Nonetheless, at high solid loadings (i.e. TS level>10%), the digestion performance was affected by chemical inhibition due to ammonia and/or humic acid. Thermophilic temperatures did not influence digestion performance but did increase start-up failure risk. Further, inoculation of residues from the batch digestion to subsequent batch enhanced start-up and achieved full methane potential recovery of the bedding. Inoculation with liquid residue (leachate) was preferred over a solid residue, to preserve treatment capacity for fresh substrate. Overall, the study highlighted that indigenous microbial community in the solid manure residue was capable of recovering full methane potential and that solid-phase digestion was ultimately limited by chemical inhibition rather than lack of suitable microbial community. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2016-06-16

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

  19. Amixicile, a novel strategy for targeting oral anaerobic pathogens.

    Science.gov (United States)

    Hutcherson, Justin A; Sinclair, Kathryn M; Belvin, Benjamin R; Gui, Qin; Hoffman, Paul S; Lewis, Janina P

    2017-09-05

    The oral microflora is composed of both health-promoting as well as disease-initiating bacteria. Many of the disease-initiating bacteria are anaerobic and include organisms such as Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Tannerella forsythia. Here we investigated a novel therapeutic, amixicile, that targets pyruvate:ferredoxin oxidoreductase (PFOR), a major metabolic enzyme involved in energy generation through oxidative decarboxylation of pyruvate. PFOR is present in these anaerobic pathogenic bacteria and thus we hypothesized that amixicile would effectively inhibit their growth. In general, PFOR is present in all obligate anaerobic bacteria, while oral commensal aerobes, including aerotolerant ones, such as Streptococcus gordonii, use pyruvate dehydrogenase to decarboxylate pyruvate. Accordingly, we observed that growth of the PFOR-containing anaerobic periodontal pathogens, grown in both monospecies as well as multispecies broth cultures was inhibited in a dose-dependent manner while that of S. gordonii was unaffected. Furthermore, we also show that amixicile is effective against these pathogens grown as monospecies and multispecies biofilms. Finally, amixicile is the first selective therapeutic agent active against bacteria internalized by host cells. Together, the results show that amixicile is an effective inhibitor of oral anaerobic bacteria and as such, is a good candidate for treatment of periodontal diseases.

  20. Odor from anaerobic digestion of swine slurry: influence of pH, temperature and organic loading

    Directory of Open Access Journals (Sweden)

    Gerardo Ortiz

    2014-12-01

    Full Text Available Farm slurry management from storage and/or treatment is the main source of odors from swine production, which are determined by factors such as operational variations (organic loading, cleaning of facilities and animal diet (pH or environmental conditions (temperature. The aim of this study was to evaluate the influence of pH, temperature and organic loading on odor generation during anaerobic digestion of swine slurry. The methodology employed batch experimental units under controlled pH (6.0, 6.5, 7.0 and 8.0 and temperature (20, 35 and 55 °C conditions. Additionally, an Upflow Anaerobic Sludge Blanket (UASB system was operated under two Organic Loading Rate (OLR conditions as Chemical Oxygen Demand (COD (Phase I: 0.4 g L-1 d-1 of COD, Phase II: 1.1 g L-1 d-1 of COD. Odor (batch and UASB reactor was evaluated by detection and recognition threshold as Dilution Threshold (D-T. Acidic conditions (pH 6.0 and thermophilic temperatures (55 °C increased odors (1,358 D-T and acidified the system (Intermediate/Total Alkalinity ratio (IT/TA: 0.85 in batch experiments. Increasing OLR on UASB reactor reduced odors from 6.3 to 9.6 D-T d-1 due to an increase in the production of biogas (0.4 to 0.6 g g-1 COD removed of biogas.

  1. The utility of anaerobic blood culture in detecting facultative anaerobic bacteremia in children.

    Science.gov (United States)

    Shoji, Kensuke; Komuro, Hisako; Watanabe, Yasushi; Miyairi, Isao

    2013-08-01

    Routine anaerobic blood culture is not recommended in children because obligate anaerobic bacteremia is rare in the pediatric population. However, a number of facultative anaerobic bacteria can cause community and hospital acquired infections in children and the utility of anaerobic blood culture for detection of these organisms is still unclear. We conducted a retrospective analysis of all blood culture samples (n = 24,356) at a children's hospital in Japan from October 2009 to June 2012. Among the samples that had paired aerobic and anaerobic blood cultures, 717 samples were considered clinically significant with 418 (58%) organisms detected from both aerobic and anaerobic cultures, 167 (23%) detected only from aerobic culture and 132 (18%) detected only from anaerobic culture. While most facultative anaerobes were detectable by aerobic culture, over 25% of Enterobacteriaceae and 15% of Staphylococcus sp. were detected from anaerobic cultures bottles only, suggesting its potential role in selected settings. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. 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......, 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......-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...

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

    Science.gov (United States)

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

    2009-04-01

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

  4. Anaerobic degradation of organic municipal solid waste together with liquid manure. Part 1; Anaerob nedbrydning af organisk husholdningsaffald sammen med gylle. Del 1

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, H.; Angelidaki, I.; Ahring, B.K.

    2001-01-01

    This project includes preliminary investigations about anaerobic degradation of organic municipal waste together with liquid manure. Investigations consist of characterization of organic municipal waste and preliminary test of anaerobic degradation of the waste. Characterization is related especially to the contents of environmentally hazardous substances, while the degradation process is characterized by means of determination of biogas potential in batch test and methane yield, organic VS (volatile solids) reduction and process stability in reactor test. In relation to environmentally hazardous substances the content of NPE and LAS in all tests of organic municipal waste was insignificant. The main problem was the content of DEHP, concentration of which is half of the cut-off value in the municipal waste. By TS (Total solid) reduction through the biogas process the DEHP concentration will thus exceed the cut-off value pr kg TS in the effluent if DEHP is not removed at the same time. The PAH concentration in the collected waste was only in one case at the level of the cut-off value which would exceed the cut-off value if no removal happens through the anaerobic degradation. The biogas potential of municipal waste was determined to be 187 m{sup 3}biogas/m{sup 3}waste, which makes organic municipal waste a very attractive waste type for biogas plants. No direct restraint by degradation of clean waste in batch test could be demonstrated. In the reactor test a stable degradation of organic municipal waste with an increasing supply of waste in mixture with manure could be established. By treatment of a mixture of municipal waste and manure in ratio to 50 : 50 a methane yield on 350 lCH{sub 4} kg VS and a VS-reduction between 50% and 60% could be obtained. Using clean municipal waste diluted with water the methane yield was higher than in the batch test and a VS reduction of up to 80% could be obtained. The analyses of DEHP and PAH in influent and effluent of the

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

    DEFF Research Database (Denmark)

    Rezende, Julia Rosa de; Kjeldsen, Kasper Urup; Hubert, Casey RJ

    2013-01-01

    S rRNA and of the dissimilatory (bi)sulfite reductase (dsrAB) genes within the endospore-forming SRB genus Desulfotomaculum. The thermophilic Desulfotomaculum community in Aarhus Bay sediments consisted of at least 23 species-level 16S rRNA sequence phylotypes. In two cases, pairs of identical 16S r......RNA and dsrAB sequences in Arctic surface sediment 3000km away showed that the same phylotypes are present in both locations. Radiotracer-enhanced most probable number analysis revealed that the abundance of endospores of thermophilic SRB in Aarhus Bay sediment was ca. 104 per cm3 at the surface and decreased...... in water masses preceding sedimentation. The sources of these thermophiles remain enigmatic, but at least one source may be common to both Aarhus Bay and Arctic sediments....

  6. Microbiology of Kamchatka Peninsula Hot Springs

    Science.gov (United States)

    Bonch-Osmolovsk, E.

    2005-12-01

    Hot springs of Uzon Caldera, Geyser Valley, Moutnovsky Volcano (Kamchatka Peninsula) served as the sources of isolation of numerous thermophilic prokaryotes, many of them representing new taxa. Among new isolates there were hyperthermophilic archaea - neutrophilic or acidophilic anaerobic organotrophs, able to use a wide range of polymeric organic substrates. Bacterial isolates were in majority represented by moderate thermophiles - organotrophs and lithoautotrophs. Latter group consisted of anaerobes oxidizing molecular hydrogen in the course of sulfate, sulfur or iron reduction, and of anaerobic CO-oxidizing, hydrogen-producing bacteria. Some of new isolates represented deep phylogenetic lineages in Bacteria domain. Microbial activity in Kamchatka hot springs was studied by means of radioisotopic tracing. The rates of methanogenesis, acetogenesis, inorganic carbon assimilation, acetate oxidation were determined in three different hot springs with pH ranging from 3.0 to 8.5 and water temeperature being in the range from 55 to 85oC. The results indicated the presence and activity of novel metabolic groups of thermophilic prokaryotes that so far have not been known in laboratory cultures.

  7. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2004-11-01

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

  9. Design and Fabrication of an Anaerobic Digester

    Directory of Open Access Journals (Sweden)

    M. S. Abubakar

    2017-02-01

    Full Text Available Anaerobic digester is a physical structure that provides a conducive environment for the multiplication of micro-organisms that degrades organic matter to generate biogas energy. Energy is required in agriculture for crop production, processing and storage, poultry production and electricity for farmstead and farm settlements. It is energy that propels agricultural mechanization, which minimizes the use of human and animal muscles and its inherent drudgery in agriculture. The energy demand required to meet up with the agricultural growth in Nigeria is high and growing every year. In this study the design and fabrication of an anaerobic digester was reported which is an attempt to boost energy requirement for small and medium dryland farmers in Nigeria. The design of the digester includes the following concept; the basic principles of anaerobic digestion processes, socio-economic status of the dryland farmers, amount of biogas to be produced. Finally, the digester was fabricated using locally available raw materials within the dryland area of Nigeria. At the end, preliminary flammability test was conducted and the biogas produced was found to be flammable.

  10. PENGOLAHAN LIMBAH CAIR INDUSTRI FARMASI FORMULASI DENGAN METODE ANAEROB-AEROB DAN ANAEROB-KOAGULASI

    Directory of Open Access Journals (Sweden)

    Farida Crisnaningtyas

    2016-05-01

    Full Text Available Studi ini membahas mengenai pengolahan limbah cair industri farmasi dalam skala laboratorium dengan menggunakan konsep anaerob-kimia-fisika dan anaerob-aerob. Proses anaerob dilakukan dengan menggunakan reaktor Upflow Anaerobic Sludge Bed reactor (UASBr pada kisaran OLR (Organic Loading Rate 0,5 – 2 kg COD/m3hari, yang didahului dengan proses aklimatisasi menggunakan substrat gula. Proses anaerob mampu memberikan efisiensi penurunan COD hingga 74%. Keluaran dari proses anaerob diolah lebih lanjut dengan menggunakan dua opsi proses: (1 fisika-kimia, dan (2 aerob. Koagulan alumunium sulfat dan flokulan kationik memberikan efisiensi penurunan COD tertinggi (73% pada kecepatan putaran masing-masing 100 rpm dan 40 rpm. Uji coba aerob dilakukan pada kisaran MLSS antara 4000-5000 mg/L dan mampu memberikan efisiensi penurunan COD hingga 97%. Hasil uji coba menunjukkan bahwa efisiensi penurunan COD total yang dapat dicapai dengan menggunakan teknologi anaerob-aerob adalah 97%, sedangkan kombinasi anaerob-koagulasi-flokulasi hanya mampu menurunkan COD total sebesar 72,53%. Berdasarkan hasil tersebut, kombinasi proses anaerob-aerob merupakan teknologi yang potensial untuk diaplikasikan dalam sistem pengolahan limbah cair industri farmasi. 

  11. Direct bioconversion of brown algae into ethanol by thermophilic bacterium Defluviitalea phaphyphila.

    Science.gov (United States)

    Ji, Shi-Qi; Wang, Bing; Lu, Ming; Li, Fu-Li

    2016-01-01

    Brown algae are promising feedstocks for biofuel production with inherent advantages of no structural lignin, high growth rate, and no competition for land and fresh water. However, it is difficult for one microorganism to convert all components of brown algae with different oxidoreduction potentials to ethanol. Defluviitalea phaphyphila Alg1 is the first characterized thermophilic bacterium capable of direct utilization of brown algae. Defluviitalea phaphyphila Alg1 can simultaneously utilize mannitol, glucose, and alginate to produce ethanol, and high ethanol yields of 0.47 g/g-mannitol, 0.44 g/g-glucose, and 0.3 g/g-alginate were obtained. A rational redox balance system under obligate anaerobic condition in fermenting brown algae was revealed in D. phaphyphila Alg1 through genome and redox analysis. The excess reducing equivalents produced from mannitol metabolism were equilibrated by oxidizing forces from alginate assimilation. Furthermore, D. phaphyphila Alg1 can directly utilize unpretreated kelp powder, and 10 g/L of ethanol was accumulated within 72 h with an ethanol yield of 0.25 g/g-kelp. Microscopic observation further demonstrated the deconstruction process of brown algae cell by D. phaphyphila Alg1. The integrated biomass deconstruction system of D. phaphyphila Alg1, as well as its high ethanol yield, provided us an excellent alternative for brown algae bioconversion at elevated temperature.

  12. [First Argentine consensus guidelines for in vitro antimicrobial susceptibility testing of clinically relevant anaerobic bacteria in humans/ Anaerobic Subcommittee of the Asociación Argentina de Microbiología].

    Science.gov (United States)

    Legaria, María C; Bianchini, Hebe M; Castello, Liliana; Carloni, Graciela; Di Martino, Ana; Fernández Canigia, Liliana; Litterio, Mirta; Rollet, Raquel; Rossetti, Adelaida; Predari, Silvia C

    2011-01-01

    Through time, anaerobic bacteria have shown good susceptibility to clinically useful antianaerobic agents. Nevertheless, the antimicrobial resistance profile of most of the anaerobic species related to severe infections in humans has been modified in the last years and different kinds of resistance to the most active agents have emerged, making their effectiveness less predictable. With the aim of finding an answer and for the purpose of facilitating the detection of anaerobic antimicrobial resistance, the Anaerobic Subcommittee of the Asociación Argentina de Microbiología developed the First Argentine consensus guidelines for in vitro antimicrobial susceptibility testing of clinically relevant anaerobic bacteria in humans. This document resulted from the compatibilization of the Clinical and Laboratory Standards Institute recommendations, the international literature and the work and experience of the Subcommittee. The Consensus document provides a brief taxonomy review, and exposes why and when anaerobic antimicrobial susceptibility tests should be conducted, and which antimicrobial agents can be used according to the species involved. The recommendations on how to perform, read and interpret in vitro anaerobic antimicrobial susceptibility tests with each method are exposed. Finally, the antibiotic susceptibility profile, the classification of antibiotics according to their in vitro activities, the natural and acquired mechanisms of resistance, the emerging resistance and the regional antibiotic resistance profile of clinically relevant anaerobic species are shown.

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

    Science.gov (United States)

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

    2017-09-01

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

  14. Increased saccharification of kallar grass using ultrafiltrated enzyme from sporrotrichum thermophile

    International Nuclear Information System (INIS)

    Latif, F.; Rajoka, M.I.; Malik, K.A.

    1991-01-01

    The local wild type strain of sporotrichum thermophile when grown on untreated lingo cellulose was found to produce a greater level of B-glucosidase component along with other cellulase/xylanase components than most of the reported wild type potent strains. Culture filtrate obtained, when grown on 4% leptochloa fusca (kallar grass) was used as such and after concentration by ultrafiltration technique for saccharification purpose. Concentrated enzymes titre was increased to 1.2 and 4.0 U/ml for Fp-ase and B-glucosidase, respectively. There were losses in the enzyme titre obtained through ultrafiltration possibly due to adsorption on to the ultrafiltration membrane. Enzyme preparations used, saccharifide 5% kallar grass to 70, 55, 75 and 60% (theoretical basis) from cellulases of S. thermophile concentrate, dilute, T. reesei alone and in supplementation with B-glucosidase from A. niger, respectively. Analysis by HPLC revealed slightly higher glucose yield from S. thermophile enzyme preparations, whereas higher level of xylose was attained from T. reesei preparations. Rest of the sugars pooled as Oligo-sugars were found in almost similar concentrations. (author)

  15. Iron minerals formed by dissimilatory iron-and sulfur reducing bacteria studied by Moessbauer spectrometry

    International Nuclear Information System (INIS)

    Chistyakova, N. I.; Rusakov, V. S.; Nazarova, K. A.; Koksharov, Yu. A.; Zavarzina, D. G.; Greneche, J.-M.

    2008-01-01

    Zero-field and in-field Moessbauer investigations and electron paramagnetic resonance (EPR) measurements to follow the kinetics of the iron mineral formation by thermophilic dissimilatory anaerobic Fe(III)-reducing bacteria (strain Z-0001) and anaerobic alkaliphilic bacteria (strain Z-0531) were carried out.

  16. Farm-scale thermophilic co-digestion of dairy manure with a biodiesel byproduct in cold regions

    International Nuclear Information System (INIS)

    Andriamanohiarisoamanana, Fetra J.; Yamashiro, Takaki; Ihara, Ikko; Iwasaki, Masahiro; Nishida, Takehiro; Umetsu, Kazutaka

    2016-01-01

    Highlights: • Co-digestion of dairy manure and crude glycerin was conducted using a 60 m"3 reactor. • The highest methane yield was 0.323 m"3/kgVS obtained at 4.2% (v/v) of crude glycerin. • The optimum organic loading rate for crude glycerol was 1.32 kgVS_C_G/m"3 d. • Reactor energy self-sufficiency was observed with net energy output of 25 kW h/d. - Abstract: Conversion of organic wastes into applicable energy sources is the best way to improve organic waste management. In this study, the performance of thermophilic co-digestion of dairy manure (DM) and crude glycerol (CG) in a 60-m"3 farm-scale biogas digester located in a cold region was investigated during the winter. Compared to the anaerobic digestion of DM alone, the methane production increased by approximately twofold during co-digestion of DM and CG. The highest methane yield was 0.323 m"3/kgVS obtained at 4.2% (v/v) of CG. Despite the increase in methane production with organic loading rate, the methane yield of CG reduced remarkably at 2.64 kgVS_C_G/m"3 d, while the highest was at 1.32 kgVS_C_G/m"3 d. During the co-digestion, a net energy at an average of 25 kWh/d was obtained for farm operation, whereas a supply of kerosene and electricity from national grid were required for the digester and farm operations during anaerobic digestion of DM. During winter, the improvement of biogas yield through the addition of CG enabled the sustainability of a farm-scale biogas production system and reduced its environmental impact.

  17. 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.

  18. 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)

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

    Science.gov (United States)

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

    2008-06-01

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

  20. Anaerobic Co-digestion of Fresh Maize Leaves with Elephant Grass ...

    African Journals Online (AJOL)

    MICHAEL HORSFALL

    antagonistic effect of co-digestion of the substrates on biogas production in order to establish the best blend. Six different ... obligate hydrogen-producing acetogens. Finally in .... Impact of food industrial waste on anaerobic co- digestion of ...