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Sample records for anaerobic thermophiles annual

  1. Anaerobic thermophiles.

    PubMed

    Canganella, Francesco; Wiegel, Juergen

    2014-02-26

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

  2. Anaerobic Thermophiles

    PubMed Central

    Canganella, Francesco; Wiegel, Juergen

    2014-01-01

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

  3. Anaerobic thermophilic culture

    DOEpatents

    Ljungdahl, Lars G.; Wiegel, Jurgen K. W.

    1981-01-01

    A newly discovered thermophilic anaerobe is described that was isolated in a biologically pure culture and designated Thermoanaerobacter ethanolicus ATCC 3/550. T. Ethanolicus is cultured in aqueous nutrient medium under anaerobic, thermophilic conditions and is used in a novel process for producing ethanol by subjecting carbohydrates, particularly the saccharides, to fermentation action of the new microorganism in a biologically pure culture.

  4. The hemicellulases from the ethanologenic thermophile, Thermoanaerobacter ethanolicus and similar anaerobic thermophiles. Annual technical progress report

    SciTech Connect

    Wiegel, J.

    1995-07-01

    A Xylanase was fractionated from Thermoanaerobacter ethanolicus, an ethanologenic thermophile, and the preparation so obtained was used to determined enzymatic parameters such as pH profile of enzyme activity. The ability of various mono- and di-saccharides as well as temperature variations to induce this enzyme activity were studied.

  5. Anaerobic thermophilic culture system

    DOEpatents

    Ljungdahl, Lars G.; Wiegel, Jurgen K. W.

    1981-01-01

    A mixed culture system of the newly discovered microorganism Thermoanaerobacter ethanolicus ATCC31550 and the microorganism Clostridium thermocellum ATCC31549 is described. In a mixed nutrient culture medium that contains cellulose, these microorganisms have been coupled and cultivated to efficiently ferment cellulose to produce recoverable quantities of ethanol under anaerobic, thermophilic conditions.

  6. Hemicellulases from anaerobic thermophiles. Progress report

    SciTech Connect

    Wiegel, J.

    1994-05-01

    The longterm goal of this research effort is to obtain an anaerobic thermophilic bacterium that efficiently converts various hemicellulose-containing biomass to ethanol over a broad pH range. The strategy is to modify the outfit and regulation of the rate-limiting xylanases, glycosidases and xylan esterases in the ethanologenic, anaerobic thermophile Thermoanaerobacter ethanolicus, which grows between pH 4.5 and 9.5. Although it utilizes xylans, the xylanase, acetyl(xylan) esterase and O-methylglucuronidase activities in T. ethanolicus are barely measurable and regarded as the rate limiting steps in its xylan utilization. Thus, and also due to the presently limited knowledge of hemicellulases in anaerobic thermophiles, we characterize the hemicellulolytic enzymes from this and other anaerobic thermophiles as enzyme donors. Beside the active xylosidase/arabinosidase from T. ethanolicus, exhibiting the two different activities, we characterized 2 xylosidases, two acetyl(xylan) esterases, and an O-methylglucuronidase from Thermoanaerobacterium spec. We will continue with the characterization of xylanases from novel isolated slightly acidophilic, neutrophilic and slightly alkalophilic thermophiles. We have cloned, subcloned and partially sequenced the 165,000 Da (2 x 85,000) xylosidase/arabinosidase from T. ethanolicus and started with the cloning of the esterases from Thermoanaerobacterium spec. Consequently, we will develop a shuttle vector and continue to apply electroporation of autoplasts as a method for cloning into T. ethanolicus.

  7. Evaluation of thermophilic anaerobic digestion

    SciTech Connect

    Shamskhorzani, R.

    1989-01-01

    The objectives of this study were to examine the effect of temperature on the digestion of a synthetic substrate, alone and with waste activated sludge (WAS), and to determine the effect of nickel, cobalt and molybdenum on thermophilic digestion. Two different types of reactors, batch fed and continuous flow, were operated in four separate phases for over two years. The data indicated that thermophilic digestion could be established from digesting mesophilic domestic sewage sludge by setting the temperature at 50C. An additional acclimation period of about 15 days was required for stimulation of thermophilic bacteria at 60C. Thermophilic digestion at temperatures up to 75C could easily be established in a few days, provided that the digester was well adapted at 60C. The rate of metabolism increased with temperature, reaching an optimum between 60C and 65C. It was possible to shift from 50C to 37C and back to thermophilic temperatures with a minimum of difficulties. Temperature fluctuation of less than 5C did not cause any upset in the performance of the thermophilic digesters operating at 50C to 65C. Addition of Ni, Co and Mo at 1 mg/L appeared to be satisfactory with the suspended solids maintained in the system at long SRT periods. The best substrate removal at 50C was 99.6% reduction at 10 g/L/d COD and 99.6% reduction at 14 g/L/d COD at 55C. The limits for COD loading under a once daily batch fed operations were 24 g/d at 50C and 33 g/d at 55C. The continuous flow fixed-film digester was able to digest WAS with liquid detention times as short as 8 hours. Thirty percent digestion of the volatile solids in WAS was obtained at a 3-day LDT and 16% at an 8-hr LDT.

  8. (Microbial ecology of thermophilic anaerobic digestion): (Progress report, Year 4)

    SciTech Connect

    Zinder, S.H.

    1988-01-01

    The goal of this project is to gain a more complete understanding of the microorganisms converting a lignocellulose waste to methane in a thermophilic (58/degree/C) anaerobic bioreactor. We have directly examined microbial populations in the bioreactor and have examined the properties of microorganisms isolated from the bioreactor. The primary focus has been on anaerobic thermophiles involved in the formation and degradation of acetic acid, the precursor of two-thirds of the methane produced in the bioreactor. Also, novel organisms of fundamental and practical significance have been isolated and characterized.

  9. The contribution of thermophilic anaerobic digestion to the stable operation of wastewater sludge treatment.

    PubMed

    Zábranská, J; Dohányos, M; Jenícek, P; Zaplatílková, P; Kutil, J

    2002-01-01

    Thermophilic anaerobic digestion of sewage sludge has been successfully operated in full-scale tanks almost three years. The higher loading capacity and specific biogas production rate in comparison with mesophilic digestion was proved. Thermophilic anaerobic sludge is also more resistant against foaming problems. Biogas from thermophilic tanks contains less hydrogen sulphide and other malodorous substances. Pathogens removal rate is apparently more efficient in the thermophilic process.

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

    PubMed

    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.

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

    PubMed

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

    2009-10-15

    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 degrees C) and thermophilic (55 degrees 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 6g COD/Ld in mesophilic conditions and at OLRs from 0.9 to 9 g COD/Ld in thermophilic conditions. COD removal efficiencies of 80-90% were achieved for OLRs up to 4.5 g COD/Ld in mesophilic conditions, while the highest OLRs i.e. 9 g COD/Ld 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/Ld. 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.

  12. Comparison of the mesophilic and thermophilic anaerobic digestion of spent cow bedding in leach-bed reactors.

    PubMed

    Riggio, S; Hernandéz-Shek, M A; Torrijos, M; Vives, G; Esposito, G; van Hullebusch, E D; Steyer, J P; Escudié, R

    2017-06-01

    Anaerobic digestion of spent cow bedding in batch leach-bed reactors (LBRs) was compared in mesophilic and thermophilic conditions for the first time. Results show that the use of thermophilic conditions enhanced only the degradation kinetics of easily-degradable matter during the first days of the digestion, whereas similar methane yields (80% of the Biomethane Potential) were reached after 42days at both temperatures. Therefore, the anaerobic digestion in LBRs of spent cow bedding, a substrate rich in slowly-degradable compounds, was not improved in term of methane production considering the overall digestion time. Moreover, the high initial biogas production rate in thermophilic reactors was found to significantly reduce the energetic performance of the cogeneration unit at industrial scale, leading to a 5.9% decrease in the annual electricity production when compared to a mesophilic one.

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

    PubMed

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

    2017-09-01

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

    PubMed

    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.

  15. Thermophilic anaerobic digester with ultrafilter for solids stabilization.

    PubMed

    Zitomer, D H; Bachman, T C; Vogel, D S

    2005-01-01

    A thermophilic anaerobic digester with ultrafilter (TADU) for solids separation offers potential advantages of higher VS destruction, biomass retention, and pathogen removal. However, potential disadvantages include ultrafilter fouling, decreasing flux, and high VFA concentrations. In this study, a thermophilic anaerobic digester coupled to a sintered titanium, cross-flow ultrafilter was operated for over five months. Dairy manure was digested (HRT of 23 days). The filtrate VFA concentration was low (220 mg/L as HAc), average VS destruction was 49%, and a low average effluent fecal coliform concentration of 10(2) MPN/100 mL was observed. The low coliform value may be beneficial if dewatered biosolids are used for livestock bedding since low pathogen counts help prevent mastitis. Ultrafilter fluxes of 40-80 L/m2-hr were maintained by cleaning using caustic (3.5% NaOH) followed by water and acid (3% phosphoric acid). Sand from livestock bedding was found to damage the pump and ultrafilter. If TADU were implemented at full scale, then replacing sand bedding with dewatered biosolids should be considered.

  16. Impact of ammonia and sulphate concentration on thermophilic anaerobic digestion.

    PubMed

    Siles, J A; Brekelmans, J; Martín, M A; Chica, A F; Martín, A

    2010-12-01

    The effect of increasing concentrations of ammonia and sulphate on thermophilic anaerobic digestion (52 degrees C) was studied at laboratory-scale. The substrate consisted of a synthetic solution supplemented with ammonia and sodium sulphate. In terms of biogas production, the results showed that the C/N and C/SO(4)(2-) thresholds were 4.40 and 1.60, respectively, corresponding to 620 mg FA (free ammonia)/L and 1400 mg SO(4)(2-)/L. No reduction in biogas production was observed until reaching the above concentration of sulphate in the sulphate toxicity test. However, when the concentration of ammonia was increased to 620 mg FA/L in the ammonia toxicity test, a gradual decrease of 21% was observed for the biogas. In order to characterise each set of experiments kinetically, a biogas production first-order kinetic model was used to fit the experimental data. The proposed model accurately predicted the behaviour of the microorganisms affecting the thermophilic anaerobic digestion, allowing its evolution to be predicted. 2010 Elsevier Ltd. All rights reserved.

  17. Rapid start-up of thermophilic anaerobic digestion with the turf fraction of MSW as inoculum.

    PubMed

    Suwannoppadol, Suwat; Ho, Goen; Cord-Ruwisch, Ralf

    2011-09-01

    This study aims to determine suitable start-up conditions and inoculum sources for thermophilic anaerobic digestion. Within days of incubation MSW at 55°C, methane was produced at a high rate. In an attempt to narrow down which components of typical MSW contained the thermophilic methanogens, vacuum cleaner dust, banana peel, kitchen waste, and garden waste were tested as inoculum for thermophilic methanogenesis with acetate as the substrate. Results singled out grass turf as the key source of thermophilic acetate degrading methanogenic consortia. Within 4 days of anaerobic incubation (55°C), anaerobically incubated grass turf samples produced methane accompanied by acetate degradation enabling successful start-up of thermophilic anaerobic digestion. Other essential start-up conditions are specified. Stirring of the culture was not conducive for successful start-up as it resulted specifically in propionate accumulation. Copyright © 2011 Elsevier Ltd. All rights reserved.

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

    PubMed

    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.

  19. Kinetics of thermophilic anaerobes in fixed-bed reactors.

    PubMed

    Perez, M; Romero, L I; Sales, D

    2001-08-01

    The main objective of this study is to estimate growth kinetic constants and the concentration of "active" attached biomass in two anaerobic thermophilic reactors which contain different initial sizes of immobilized anaerobic mixed cultures and decompose distillery wastewater. This paper studies the substrate decomposition in two lab-scale fixed-bed reactors operating at batch conditions with corrugated tubes as support media. It can be demonstrated that high micro-organisms-substrate ratios favor the degradation activity of the different anaerobic cultures, allowing the stable operation without lag-phases and giving better quality in effluent. The kinetic parameters obtained--maximum specific growth rates (mu(max)), non-biodegradable substrate (S(NB)) and "active or viable biomass" concentrations (X(V0))--were obtained by applying the Romero kinetic model [L.I. Romero, 1991. Desarrollo de un modelo matemático general para los procesos fermentativos, Cinética de la degradación anaerobia, Ph.D. Thesis, University of Cádiz (Spain), Serv. Pub. Univ. Cádiz], with COD as substrate and methane (CH4) as the main product of the anaerobic process. This method is suitable to calculate and to differentiate the main kinetic parameters of both the total anaerobic mixed culture and the methanogenic population. Comparison of experimental measured concentration of volatile attached solids (VS(att)) in both reactors with the estimated "active" biomass concentrations obtained by applying Romero kinetic model [L.I. Romero, 1991. Desarrollo de un modelo matemático general para los procesos fermentativos, Cinética de la degradación anaerobia, Ph.D. Thesis, University of Cádiz (Spain), Serv. Pub. Univ. Cádiz] shows that a large amount of inert matter is present in the fixed-bed reactor.

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

    PubMed

    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.

  1. Comparative mesophilic and thermophilic anaerobic digestion of palm oil mill effluent using upflow anaerobic sludge blanket.

    PubMed

    Khemkhao, Maneerat; Nuntakumjorn, Boonyarit; Techkarnjanaruk, Somkiet; Phalakornkule, Chantaraporn

    2012-07-01

    The effects of organic loading rate and operating temperature on the microbial diversity and performances of upflow anaerobic sludge blanket (UASB) reactors treating palm oil mill effluent (POME) were investigated. The following two UASB reactors were run in parallel for comparison: (1) under a mesophilic condition (37 degrees C) and (2) under a mesophilic condition in transition to a thermophilic condition (57 degrees C). A polymerase chain reaction (PCR)-based denaturing gradient gel electrophoresis (DGGE) analysis showed that the microbial population profiles significantly changed with the organic loading rate (OLR) and the temperature transition from the mesophilic to the thermophilic condition. Significant biomass washout was observed for the mesophilic UASB when operating at a high organic loading rate (OLR) of 9.5 g chemical oxygen demand (COD)/L.d. In contrast, the thermophilic UASB can be operated at this OLR and at a temperature of 57 degrees C with satisfactory COD removal and biogas production. The PCR-based DGGE analysis suggested that the thermophilic temperature of 57 degrees C was suitable for a number of hydrolytic, acidogenic, and acetogenic bacteria.

  2. High-rate thermophilic anaerobic digestion of agricultural wastes

    SciTech Connect

    Shelef, G.; Kimchie, S.; Grynberg, H.

    1980-01-01

    There are many settlements in Israel known as Kibbutzim which provide an interface between the agricultural sector, the industrial sector, and a community with a high per capita energy consumption. Hence, these settlements provide an ideal site for the operation of anaerobic digestion for the treatment of agricultural wastes and the utilization of the resultant energy supply. While the substrate initially used in this study was dairy-cow manure collected from the concrete floors of corrals, the contribution of other organic wastes such as straw, cotton plants, and chicken manure was also evaluated. It has been reported in the literature that some materials when added to the anaerobic digestion process lead to enhancement of gas production and improvement in digester operation. Hence, the effects on the performance of highly loaded thermophilic digesters of several materials such as activated carbon, cobalt salts, and calcium hydroxide were examined in this study. Pilot-plant units of 1000 and 10,000 liter were an intergral part of the study program. These units were used to verify results obtained with the 4-liter laboratory units. An energy survey was conducted on the larger units. These units were also used to supply large quantities of gas for utilization experiments and to provide the large quantities of digested sludge required for animal-feeding trials and fertilizer experiments. The pilot-plant units also afforded the opportunity to solve technical problems which would arise in full-size units.

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

    NASA Astrophysics Data System (ADS)

    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).

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

    SciTech Connect

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

    2016-06-16

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

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

    DOE PAGES

    Herring, Christopher D.; Kenealy, William R.; Shaw, A. Joe; ...

    2016-06-16

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

  6. Draft Genome of Thermanaerothrix daxensis GNS-1, a Thermophilic Facultative Anaerobe from the Chloroflexi Class Anaerolineae

    PubMed Central

    Pace, Laura A.; Ward, Lewis M.; Fischer, Woodward W.

    2015-01-01

    We present the draft genome of Thermanaerothrix daxensis GNS-1, a thermophilic member of the Chloroflexi phylum. This organism was initially characterized as a nonmotile, strictly anaerobic fermenter; however, genome analysis demonstrates that it encodes genes for a flagellum and multiple pathways for aerobic and anaerobic respiration. PMID:26586891

  7. Thermal adaptation in yeast: obligate psychrophiles are obligate aerobes, and obligate thermophiles are facultative anaerobes.

    PubMed Central

    Watson, K; Arthur, H; Morton, H

    1978-01-01

    The obligate psychrophilic yeasts Torulopsis psychrophila, T. austromarina, Leucosporidium frigidum, L. gelidum, and L. nivalis were obligate aerobes and were unable to grow anaerobically. In contrast, the obligate thermophilic yeasts T. bovina, T. pintolopesii, Candida slooffii, and Saccharomyces telluris were facultative anaerobes. PMID:568620

  8. Anaerobic treatment performance and microbial population of thermophilic upflow anaerobic filter reactor treating awamori distillery wastewater.

    PubMed

    Tang, Yue-Qin; Fujimura, Yutaka; Shigematsu, Toru; Morimura, Shigeru; Kida, Kenji

    2007-10-01

    Distillery wastewater from awamori making was anaerobically treated for one year using thermophilic upflow anaerobic filter (UAF) reactors packed with pyridinium group-containing nonwoven fabric material. The microbial structure and spatial distribution of microorganisms on the support material were characterized using molecular biological methods. The reactor steadily achieved a high TOC loading rate of 18 g/l/d with approximately 80% TOC removal efficiency when non-diluted wastewater was fed. The maximum TOC loading rate increased to 36 g/l/d when treating thrice-diluted wastewater. However, the TOC removal efficiency and gas evolution rate decreased compared with that when non-diluted wastewater was used. Methanogens closely related to Methanosarcina thermophila and Methanoculleus bourgensis and bacteria in the phyla Firmicutes and Bacteroidetes were predominant methanogens and bacteria in the thermophilic UFA reactor, as indicated by 16S rRNA gene clone analysis. Fluorescence in situ hybridization (FISH) results showed that a large quantity of bacterial cells adhered throughout the whole support, and Methanosarcina-like methanogens existed mainly in the relative outside region while Methanoculleus cells were located in the relative inner part of the support. The support material used proved to be an excellent carrier for microorganisms, and a UAF reactor using this kind of support can be used for high-rate treatment of awamori/shochu distillery wastewater.

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

    PubMed

    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.

  10. Treatment of brewery slurry in thermophilic anaerobic sequencing batch reactor.

    PubMed

    Zupancic, Gregor D; Straziscar, Matej; Ros, Milenko

    2007-10-01

    Treatment of brewery slurry in a thermophilic anaerobic sequencing batch reactor (ASBR) was studied using conventional fully mixed semi-continuous digestion as a control. The process phases were adapted to fit the brewery slurry discharge schedule. ASBR experiments were conducted under different organic loading rates (OLR) from 3.23 to 8.57 kg of COD/m(3)day of reactor and control was conducted with OLR of 3.0 kg of COD/m(3)day. The ASBR COD degradation efficiency was from 79.6% to 88.9%, control experiment efficiency was 65%. ASBR VSS removal efficiency was from 78.5% to 90.5%, control experiment efficiency was 54%. The ASBR methane production yield was from 371 to 418 L/kg COD inserted, control experiment methane yield was 248 L/kg COD inserted. The ASBR process was superior to conventional fully mixed digestion, and is fully adaptable to brewery slurry discharge, needs no additional collection and settling pools and experiences no solids settling problems.

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

    SciTech Connect

    Wiegel, J.

    1998-05-01

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

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

    SciTech Connect

    Wiegel, J.

    1998-09-01

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

  13. Monitoring of thermophilic adaptation of mesophilic anaerobe fermentation of sugar beet pressed pulp.

    PubMed

    Tukacs-Hájos, Annamária; Pap, Bernadett; Maróti, Gergely; Szendefy, Judit; Szabó, Piroska; Rétfalvi, Tamás

    2014-08-01

    Anaerobe fermentation of sugar beet pressed pulp was investigated in pilot-scale digesters. Thermophilic adaptation of mesophilic culture was monitored using chemical analysis and metagenomic characterization of the sludge. Temperature adaptation was achieved by increasing the temperature gradually (2 °C day(-1)) and by greatly decreasing the OLR. During stable run, the OLR was increased gradually to 11.29 kg VS m(-3)d(-1) and biogas yield was 5% higher in the thermophilic reactor. VFA levels increased in the thermophilic reactor with increased OLR (acetic acid 646 mg L(-1), propionic acid 596 mg L(-1)), then VFA decreased and the operation was manageable beside the relative high tVFA (1300-2000 mg L(-1)). The effect of thermophilic adaptation on the microbial communities was studied using a sequencing-based metagenomic approach. Connections between physico-chemical parameters and populations of bacteria and methanogen archaea were revealed.

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

    PubMed

    Wang, Wei; Ma, Wencheng; Han, Hongjun; Li, Huiqiang; Yuan, Min

    2011-02-01

    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°C) reactor as a control, thermophilic anaerobic digestion (55±2°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(3) d) and HRT of 24 h; 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 pretreatment was done. The results suggested that thermophilic anaerobic digestion improved significantly both anaerobic and aerobic biodegradation of LCGW.

  15. Anaerobic High-Throughput Cultivation Method for Isolation of Thermophiles Using Biomass-Derived Substrates

    SciTech Connect

    Hamilton-Brehm, Scott; Vishnivetskaya, Tatiana A; Allman, Steve L; Mielenz, Jonathan R; Elkins, James G

    2012-01-01

    Flow cytometry (FCM) techniques have been developed for sorting mesophilic organisms, but the difficulty increases if the target microbes are thermophilic anaerobes. We demonstrate a reliable, high-throughput method of screening thermophilic anaerobic organisms using FCM and 96-well plates for growth on biomass-relevant substrates. The method was tested using the cellulolytic thermophiles Clostridium ther- mocellum (Topt = 55 C), Caldicellulosiruptor obsidiansis (Topt = 78 C) and the fermentative hyperthermo- philes, Pyrococcus furiosus (Topt = 100 C) and Thermotoga maritima (Topt = 80 C). Multi-well plates were incubated at various temperatures for approximately 72 120 h and then tested for growth. Positive growth resulting from single cells sorted into individual wells containing an anaerobic medium was verified by OD600. Depending on the growth substrate, up to 80 % of the wells contained viable cultures, which could be transferred to fresh media. This method was used to isolate thermophilic microbes from Rabbit Creek, Yellowstone National Park (YNP), Wyoming. Substrates for enrichment cultures including crystalline cellulose (Avicel), xylan (from Birchwood), pretreated switchgrass and Populus were used to cultivate organisms that may be of interest to lignocellulosic biofuel production.

  16. Destruction by Anaerobic Mesophilic and Thermophilic Digestion of Viruses and Indicator Bacteria Indigenous to Domestic Sludges

    PubMed Central

    Berg, Gerald; Berman, Donald

    1980-01-01

    In raw sludges and in mesophilically and thermophilically digested anaerobic sludges, large variations in numbers of viruses occurred over narrow ranges of numbers of fecal coliforms, total coliforms, and fecal streptococci, demonstrating that the bacteria were poor quantitative reflectors of the numbers of the viruses detected. Mesophilic and thermophilic digestion of anaerobic sludges destroyed all three indicator bacteria more rapidly than such digestion destroyed the viruses. The relative rates for the destruction of viruses, fecal coliforms, and fecal streptococci in the digested sludges were consistent over the 17-month study. Fecal coliforms were 7 to 8 times more sensitive than the viruses to mesophilic digestion and 9 to 10 times more sensitive to thermophilic digestion. Total coliforms were even more sensitive. The rates at which fecal streptococci were destroyed by mesophilic and thermophilic digestion of anaerobic sludges approached those at which the viruses were destroyed by those processes; this suggested that the rates at which fecal streptococci in sludges are destroyed by those processes may serve as useful indicators for the rates at which viruses in sludges are destroyed by those processes. PMID:16345510

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

    PubMed

    Ahring, B K; Mladenovska, Z; Iranpour, R; Westermann, P

    2002-01-01

    The state 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 65 degrees C or more may be necessary in the future to meet the demands for full sanitation of the waste material before final disposal. We show data of anaerobic digestion at extreme thermophilic temperatures.

  18. Genome sequence of the polysaccharide-degrading, thermophilic anaerobe Spirochaeta thermophila DSM 6192.

    PubMed

    Angelov, Angel; Liebl, Susanne; Ballschmiter, Meike; Bömeke, Mechthild; Lehmann, Rüdiger; Liesegang, Heiko; Daniel, Rolf; Liebl, Wolfgang

    2010-12-01

    Spirochaeta thermophila is a thermophilic, free-living anaerobe that is able to degrade various α- and β-linked sugar polymers, including cellulose. We report here the complete genome sequence of S. thermophila DSM 6192, which is the first genome sequence of a thermophilic, free-living member of the Spirochaetes phylum. The genome data reveal a high density of genes encoding enzymes from more than 30 glycoside hydrolase families, a noncellulosomal enzyme system for (hemi)cellulose degradation, and indicate the presence of a novel carbohydrate-binding module.

  19. Genome Sequence of the Polysaccharide-Degrading, Thermophilic Anaerobe Spirochaeta thermophila DSM 6192▿

    PubMed Central

    Angelov, Angel; Liebl, Susanne; Ballschmiter, Meike; Bömeke, Mechthild; Lehmann, Rüdiger; Liesegang, Heiko; Daniel, Rolf; Liebl, Wolfgang

    2010-01-01

    Spirochaeta thermophila is a thermophilic, free-living anaerobe that is able to degrade various α- and β-linked sugar polymers, including cellulose. We report here the complete genome sequence of S. thermophila DSM 6192, which is the first genome sequence of a thermophilic, free-living member of the Spirochaetes phylum. The genome data reveal a high density of genes encoding enzymes from more than 30 glycoside hydrolase families, a noncellulosomal enzyme system for (hemi)cellulose degradation, and indicate the presence of a novel carbohydrate-binding module. PMID:20935097

  20. Anaerobic digestion of mixed microalgae cultivated in secondary effluent under mesophilic and thermophilic conditions.

    PubMed

    Cea-Barcia, Glenda; Moreno, Gloria; Buitrón, Germán

    2015-01-01

    The anaerobic digestion of mixed indigenous microalgae, grown in a secondary effluent, was evaluated in batch tests at mesophilic (35°C) and thermophilic (50°C) conditions. Under mesophilic conditions, specific methane production varied from 178 to 207 mL CH4/g volatile solids (VS) and the maximum production rate varied from 8.8 to 26.1 mL CH4/(gVS day), depending on the type of microalgae culture. Lower methane parameters were observed in those cultures where Scenedesmus represents more than 95% of the microalge. The culture with the lowest digestion performances under mesophilic conditions was studied under thermophilic conditions. The increase in the incubation temperature significantly increased the specific methane production (390 mL CH4/g VS) and rate (26.0 mL CH4/(gVS day)). However, under thermophilic conditions a lag period of 30 days was observed.

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

    PubMed

    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.

  2. Removal of helminth eggs and fecal coliforms by anaerobic thermophilic sludge digestion.

    PubMed

    Cabirol, N; Rojas Oropeza, M; Noyola, A

    2002-01-01

    Anaerobic digestion of two types of waste sludge was applied in order to assess the suitability of thermophilic conditions for the stabilization of organic matter and removal of fecal coliforms and helminth eggs. Feeding sludge was taken from an activated sludge municipal facility (BS) and from an enhanced primary treatment municipal plant (EPT). As an accompanying experiment, mesophilic digesters were also operated. The four digesters (M1, M2, T1, T2) had a 5 litre volume and an egg shape. A highly stabilized material was obtained at both temperatures with BS type of sludge, taking the reduction of volatile fraction of suspended solids (%Rvss) as indicator (84% for M1 and 74% for T1). In general, EPT sludge was a more difficult substrate, if compared with BS sludge; thermophilic condition was better adapted than mesophilic for this kind of sludge. Satisfactory reductions on counts of fecal coliforms and helminth eggs were achieved under thermophilic digestion for both types of feeding sludge. T1 digester, fed with biological sludge, removed fecal coliforms below 1000 MPN/gTS and helminth eggs down to 0.28 HELarval/gTS, at an HRT of 20 days. As a general conclusion, anaerobic thermophilic digestion may be an appropriate option for sludge stabilization, in order to meet EPA Class A biosolids final disposal regulations. However, further research is needed in order to consistently remove helminth eggs and fecal coliforms from waste sludge at shorter hydraulic retention times.

  3. Microbial diversity in innovative mesophilic/thermophilic temperature-phased anaerobic digestion of sludge.

    PubMed

    Gagliano, M C; Braguglia, C M; Gallipoli, A; Gianico, A; Rossetti, S

    2015-05-01

    Anaerobic digestion (AD) is one of the few sustainable technologies that both produce energy and treat waste streams. Driven by a complex and diverse community of microbes, AD may be affected by different factors, many of which also influence the composition and activity of the microbial community. In this study, the biodiversity of microbial populations in innovative mesophilic/thermophilic temperature-phased AD of sludge was evaluated by means of fluorescence in situ hybridization (FISH). The increase of digestion temperature drastically affected the microbial composition and selected specialized biomass. Hydrogenotrophic Methanobacteriales and the protein fermentative bacterium Coprothermobacter spp. were identified in the thermophilic anaerobic biomass. Shannon-Weaver diversity (H') and evenness (E) indices were calculated using FISH data. Species richness was lower under thermophilic conditions compared with the values estimated in mesophilic samples, and it was flanked by similar trend of the evenness indicating that thermophilic communities may be therefore more susceptible to sudden changes and less prompt to adapting to operative variations.

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

    PubMed

    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.

  5. Biodegradation of PAH and DEHP micro-pollutants in mesophilic and thermophilic anaerobic sewage sludge digestion.

    PubMed

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

    2006-01-01

    Anaerobic digestion for the treatment of sludge in wastewater treatment plants has been reported to produce a low organic loaded effluent with an acceptable economic cost. But in the last years, new regulations and the increasing sludge production invite us to find an alternative and/or to improve the process efficiency. Moreover, the use of the effluent as fertilizer in agriculture imposes more restrictions on digestion process product and its micropollutant contents to protect the environment. In this study, a performance of the anaerobic digestion under mesophilic and thermophilic conditions at different hydraulic retention times (HRT) is assessed and the removal efficiencies of two important compounds or family compounds (Polycyclic Aromatic Hydrocarbons, PAH, and Di-2-(Ethyl-Hexyl)-Phthalate, DEHP) are evaluated. A positive effect of thermophilic temperature was observed on both micropollutants' biodegradation. However, HRT effect also had an important role for DEHP and low molecular weighted PAH removal.

  6. Performance and energy economics of mesophilic and thermophilic digestion in anaerobic hybrid reactor treating coal wastewater.

    PubMed

    Ramakrishnan, Anushuya; Surampalli, Rao Y

    2013-01-01

    Two anaerobic hybrid AHRs (AHR), mesophilic (35 °C) and thermophilic (55 °C) were operated with coal wastewater at different hydraulic retention times (HRT) ranging from 3-0.5 to 3.12-0.6d with organic loading rates (OLR) of 1.12-6.72 g L(-1) d(-1). Synthetic coal wastewater with an average chemical oxygen demand (COD) of 2240 mg L(-1) and phenolics concentration of 752 mg L(-1) was used as substrate. At each HRT, the thermophilic AHR gave a better performance, measured in terms of phenolics/COD removal and gas production. The specific methane yield was also higher for thermophilic AHR at each HRT compared to mesophilic one. The volatile fatty acid concentration in the effluent increased with the lowering of HRT. The Stover-Kincannon model was applicable at both temperatures and showed higher substrate utilization in thermophilic AHR. Energy economic study of the AHRs revealed that 11,938 MJ d(-1) more energy can be generated using thermophilic AHR than mesophilic. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Evaluation of continuous mesophilic, thermophilic and temperature phased anaerobic digestion of microwaved activated sludge.

    PubMed

    Coelho, Nuno Miguel Gabriel; Droste, Ronald L; Kennedy, Kevin J

    2011-04-01

    The effects of microwave (MW) pretreatment, staging and digestion temperature on anaerobic digestion were investigated in a setup of ten reactors. A mesophilic reactor was used as a control. Its performance was compared to single-stage mesophilic and thermophilic reactors treating pretreated and non-pretreated sludge, temperature-phased (TPAD) thermophilic-mesophilic reactors treating pretreated and non-pretreated sludge and thermophilic-thermophilic reactors also treating pretreated and non-pretreated sludge. Four different sludge retention times (SRTs) (20, 15, 10 and 5 d) were tested for all reactors. Two-stage thermo-thermo reactors treating pretreated sludge produced more biogas than all other reactors and removed more volatile solids. Maximum volatile solids (VS) removal was 53.1% at an SRT of 15 d and maximum biogas increase relative to control was 106% at the shortest SRT tested. Both the maximum VS removal and biogas relative increase were measured for a system with thermophilic acidogenic reactor and thermophilic methanogenic reactor. All the two-stage systems treating microwaved sludge produced sludge free of pathogen indicator bacteria, at all tested conditions even at a total system SRT of only 5 d. MW pretreatment and staging reactors allowed the application of very short SRT (5 d) with no significant decrease in performance in terms of VS removal in comparison with the control reactor. MW pretreatment caused the solubilization of organic material in sludge but also allowed more extensive hydrolysis of organic material in downstream reactors. The association of MW pretreatment and thermophilic operation improves dewaterability of digested sludge. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Behavior of cellulose-degrading bacteria in thermophilic anaerobic digestion process.

    PubMed

    Syutsubo, K; Nagaya, Y; Sakai, S; Miya, A

    2005-01-01

    Previously, we found that the newly isolated Clostridium sp. strain JC3 became the dominant cellulose-degrading bacterium in thermophilic methanogenic sludge. In the present study, the behavior of strain JC3 in the thermophilic anaerobic digestion process was investigated quantitatively by molecular biological techniques. A cellulose-degrading experiment was conducted at 55 degrees C with a 9.5 L of anaerobic baffled reactor having three compartments (Nos. 1, 2, 3). Over 80% of the COD input was converted into methane when 2.5 kgCOD m(-3) d(-1) was loaded for an HRT of 27 days. A FISH probe specific for strain JC3 was applied to sludge samples harvested from the baffled reactor. Consequently, the ratio of JC3 cells to DAPI-stained cells increased from below 0.5% (undetectable) to 9.4% (compartment 1), 13.1% (compartment 2) and 21.6% (compartment 3) at day 84 (2.5 kgCOD m(-3)d(-1)). The strain JC3 cell numbers determined by FISH correlated closely with the cellulose-degrading methanogenic activities of retained sludge. A specific primer set targeting the cellulase gene (cellobiohydrolaseA: cbhA) of strain JC3 was designed and applied to digested sludge for treating solid waste such as coffee grounds, wastepaper, garbage, cellulose and so on. The strain JC3 cell numbers determined by quantitative PCR correlated closely with the cellulose-sludge loading of the thermophilic digester. Strain JC3 is thus important in the anaerobic hydrolysis of cellulose in thermophilic anaerobic digestion processes.

  9. Inactivation of Ascaris suum and poliovirus in biosolids under thermophilic anaerobic digestion conditions.

    PubMed

    Aitken, Michael D; Sobsey, Mark D; Blauth, Kimberly E; Shehee, Mina; Crunk, Phillip L; Walters, Glenn W

    2005-08-01

    There is considerable interest in the United States in production of Class A (low pathogen content) biosolids from the treatment of municipal wastewater sludge. Current requirements imposed by the U.S. Environmental Protection Agency make it difficult for thermophilic anaerobic digestion, in its simplest process configurations, to achieve Class A status. In particular, the time-temperature requirements necessitate long batch treatment times at temperatures associated with thermophilic anaerobic digestion. The time-temperature requirements are meant to ensure extensive inactivation of helminth eggs and enteric viruses, considered to be the most heat-resistant of the relevant pathogen classes. However, data on inactivation kinetics of these pathogens at precisely controlled and well-characterized temperatures are scarce. We measured inactivation of vaccine-strain poliovirus and eggs from the helminth Ascaris suum at temperatures from 49 to 55 degrees C in a lab-scale batch reactor containing biosolids from a continuous-flow thermophilic anaerobic digester. Both microbes were inactivated rapidly, with Ascaris more resistant to inactivation than poliovirus, and the relationships between inactivation rate and temperature were steep. The Arrhenius correlation between inactivation rate and temperature over the range 49-53 degrees C is consistent with protein denaturation as the inactivation mechanism for both microbes. The least stringent of the EPA time-temperature equations for thermal processes requires batch treatment times more than 2 orders of magnitude greater than would be required for three-log reduction of Ascaris at the rates we measured, suggesting an overly conservative regulatory approach. Such a grossly conservative approach can hinder full-scale implementation of thermophilic anaerobic digestion.

  10. Involvement of a novel fermentative bacterium in acidification in a thermophilic anaerobic digester.

    PubMed

    Hori, Tomoyuki; Akuzawa, Masateru; Haruta, Shin; Ueno, Yoshiyuki; Ogata, Atsushi; Ishii, Masaharu; Igarashi, Yasuo

    2014-12-01

    Acidification results from the excessive accumulation of volatile fatty acids and the breakthrough of buffering capacity in anaerobic digesters. However, little is known about the identity of the acidogenic bacteria involved. Here, we identified an active fermentative bacterium during acidification in a thermophilic anaerobic digester by sequencing and phylogenetic analysis of isotopically labeled rRNA. The digestion sludge retrieved from the beginning of pH drop in the laboratory-scale anaerobic digester was incubated anaerobically at 55 °C for 4 h during which (13)C-labeled glucose was supplemented repeatedly. (13)CH4 and (13)CO2 were produced after substrate addition. RNA extracts from the incubated sludge was density-separated by ultracentrifugation, and then bacterial communities in the density fractions were screened by terminal restriction fragment length polymorphism and clone library analyses based on 16S rRNA transcripts. Remarkably, a novel lineage within the genus Thermoanaerobacterium became abundant with increasing the buoyant density and predominated in the heaviest fraction of RNA. The results in this study indicate that a thermoacidophilic bacterium exclusively fermented the simple carbohydrate glucose, thereby playing key roles in acidification in the thermophilic anaerobic digester.

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

    PubMed

    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.

  12. Enhanced anaerobic degradability of highly polluted pesticides-bearing wastewater under thermophilic conditions.

    PubMed

    García-Mancha, N; Monsalvo, V M; Puyol, D; Rodriguez, J J; Mohedano, A F

    2017-10-05

    This work presents a sustainable and cost-competitive solution for hardly biodegradable pesticides-bearing wastewater treatment in an anaerobic expanded granular sludge bed (EGSB) reactor at mesophilic (35°C) and thermophilic (55°C). The reactor was operated in continuous mode during 160days, achieving an average COD removal of 33 and 44% under mesophilic and thermophilic conditions, respectively. The increase of temperature improved the biomass activity and the production of methane by 35%. Around 96% of pesticides identified in raw wastewater were not detected in both mesophilic and thermophilic effluents. A dramatic selection of the microbial population in anaerobic granules was caused by the presence of pesticides, which also changed significantly when the temperature was increased. Pesticides caused a significant inhibition on methanogenesis, especially over acetoclastic methanogens. Aerobic biodegradability tests of the resulting anaerobic effluents revealed that aerobic post-treatment is also a feasible and effective option, yielding more than 60% COD reduction. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Kinetic characterization of thermophilic and mesophilic anaerobic digestion for coffee grounds and waste activated sludge.

    PubMed

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

    2015-02-01

    This study was conducted to characterize the kinetics of an anaerobic process (hydrolysis, acetogenesis, acidogenesis and methanogenesis) under thermophilic (55 °C) and mesophilic (35 °C) conditions with coffee grounds and waste activated sludge (WAS) as the substrates. Special focus was given to the kinetics of propionic acid degradation to elucidate the accumulation of VFAs. Under the thermophilic condition, the methane production rate of all substrates (WAS, ground coffee and raw coffee) was about 1.5 times higher than that under the mesophilic condition. However, the effects on methane production of each substrate under the thermophilic condition differed: WAS increased by 35.8-48.2%, raw coffee decreased by 76.3-64.5% and ground coffee decreased by 74.0-57.9%. Based on the maximum reaction rate (Rmax) of each anaerobic stage obtained from the modified Gompertz model, acetogenesis was found to be the rate-limiting step for coffee grounds and WAS. This can be explained by the kinetics of propionate degradation under thermophilic condition in which a long lag-phase (more than 18 days) was observed, although the propionate concentration was only 500 mg/L. Under the mesophilic condition, acidogenesis and hydrolysis were found to be the rate-limiting step for coffee grounds and WAS, respectively. Even though reducing the particle size accelerated the methane production rate of coffee grounds, but did not change the rate-limiting step: acetogenesis in thermophilic and acidogenesis in mesophilic. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

    PubMed

    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 < 0.05) at the conditions of C/N ratio 26:1, moisture content 80 %, and natural initial pH. Although high concentrations of ammonia-nitrogen (NH4-N, 1500 mg/kg wet weight) were formed during thermophilic digestion, there was no obvious inhibition occurred. The results indicated that rice straw can be used as carbon source for the dry co-digestion of sewage sludge under mesophilic and thermophilic conditions.

  15. Thermophilic adaptation of a mesophilic anaerobic sludge for food waste treatment.

    PubMed

    Ortega, Luis; Barrington, Suzelle; Guiot, Serge R

    2008-08-01

    As opposed to mesophilic, thermophilic anaerobic digestion of food waste can increase the biogas output of reactors. To facilitate the transition of anaerobic digesters, this paper investigated the impact of adapting mesophilic sludge to thermophilic conditions. A 5L bench scale reactor was seeded with mesophilic granular sludge obtained from an up-flow anaerobic sludge blanket digester. After 13 days of operation at 35 degrees C, the reactor temperature was instantaneously increased to 55 degrees C and operated at this temperature until day 21. The biomass was then fed food waste on days 21, 42 and 63, each time with an F/M (Food/Microorganism) ratio increasing from 0.12 to 4.43 gVS/gVSS. Sludge samples were collected on days 0, 21, 42 and 63 to conduct substrate activity tests, and reactor biogas production was monitored during the full experimental period. The sludge collected on day 21 demonstrated that the abrupt temperature change had no pasteurization effect, but rather lead to a biomass with a fermentative activity of 3.58 g Glucose/gVSS/d and a methanogenic activity of 0.47 and 0.26 g Substrate/gVSS/d, related respectively, to acetoclastic and hydrogenophilic microorganisms. At 55 degrees C, an ultimate gas production (Go) and a biodegradation potential (Bo) of 0.2-1.4 L(STP)/gVS(fed) and of 0.1-0.84 L(STP) CH(4)/gVS(fed) were obtained, respectively. For the treatment of food waste, a fully adapted inoculum was developed by eliminating the initial time-consuming acclimatization stage from mesophilic to thermophilic conditions. The feeding stage was initiated within 20 days, but to increase the population of thermophilic methanogenic microorganisms, a substrate supply program must be carefully observed.

  16. Performance comparison between mesophilic and thermophilic anaerobic reactors for treatment of palm oil mill effluent.

    PubMed

    Jeong, Joo-Young; Son, Sung-Min; Pyon, Jun-Hyeon; Park, Joo-Yang

    2014-08-01

    The anaerobic digestion of palm oil mill effluent (POME) was carried out under mesophilic (37°C) and thermophilic (55°C) conditions without long-time POME storage in order to compare the performance of each condition in the field of Sumatra Island, Indonesia. The anaerobic treatment system was composed of anaerobic hybrid reactor and anaerobic baffled filter. Raw POME was pretreated by screw decanter to reduce suspended solids and residual oil. The total COD removal rate of 90-95% was achieved in both conditions at the OLR of 15kg[COD]/m(3)/d. The COD removal in thermophilic conditions was slightly better, however the biogas production was much higher than that in the mesophilic one at high OLR. The organic contents in pretreated POME were highly biodegradable in mesophilic under the lower OLRs. The biogas production was 13.5-20.0l/d at the 15kg[COD]/m(3)/d OLR, and the average content of carbon dioxide was 5-35% in both conditions.

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

    PubMed

    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.

  18. Entrapment of anaerobic thermophilic and hyperthermophilic marine micro-organisms in a gellan/xanthan matrix.

    PubMed

    Landreau, M; Duthoit, F; Claeys-Bruno, M; Vandenabeele-Trambouze, O; Aubry, T; Godfroy, A; Le Blay, G

    2016-06-01

    The aims of this study were (i) to develop a protocol for the entrapment of anaerobic (hyper)thermophilic marine micro-organisms; (ii) to test the use of the chosen polymers in a range of physical and chemical conditions and (iii) to validate the method with batch cultures. The best conditions for immobilization were obtained at 80°C with gellan and xanthan gums. After 5-week incubation, beads showed a good resistance to all tested conditions except those simultaneously including high temperature (100°C), low NaCl (<0∙5 mol l(-1) ) and extreme pH (4/8). To confirm the method efficiency, batch cultures with immobilized Thermosipho sp. strain AT1272 and Thermococcus kodakarensis strain KOD1 showed an absence of detrimental effect on cell viability and a good growth within and outside the beads. This suggests that entrapment in a gellan-xanthan matrix could be employed for the culture of anaerobic (hyper)thermophilic marine micro-organisms. (Hyper)thermophilic marine micro-organisms possess a high biotechnological potential. Generally microbial cells are grown as free-cell cultures. The use of immobilized cells may offer several advantages such as protection against phage attack, high cell biomass and better production rate of desired metabolites. © 2016 The Society for Applied Microbiology.

  19. Start-up of thermophilic-dry anaerobic digestion of OFMSW using adapted modified SEBAC inoculum.

    PubMed

    Fdéz-Güelfo, L A; Alvarez-Gallego, C; Sales Márquez, D; Romero García, L I

    2010-12-01

    The work presented here concerns the start-up and stabilization stages of a Continuous Stirred Tank Reactor (CSTR) semicontinuously fed for the treatment of the Organic Fraction of Municipal Solid Waste (OFMSW) through anaerobic digestion at thermophilic temperature range (55 degrees C) and dry conditions (30% Total Solids). The procedure reported involves two novel aspects with respect to other start-up and stabilization protocols reported in the literature. The novel aspects concern the adaptation of the inoculum to both the operating conditions (thermophilic and dry) and to the type of waste by employing a modified SEBAC (Sequential Batch Anaerobic Composting) system and, secondly, the direct start-up of the process in a thermophilic temperature regime and feeding of the system from the first day of operation. In this way a significant reduction in the start-up time and stabilization is achieved i.e. 110 days in comparison to 250 days for the processes reported by other authors for the same type of waste and digester. The system presents suitable operational conditions to stabilize the reactor at SRT of 35 days, with a maximum biogas production of 1.944 LR/L.d with a CH(4) and CO(2) percentage of 25.27% and 68.15%, respectively. 2010 Elsevier Ltd. All rights reserved.

  20. Strategies for changing temperature from mesophilic to thermophilic conditions in anaerobic CSTR reactors treating sewage sludge.

    PubMed

    Bousková, A; Dohányos, M; Schmidt, J E; Angelidaki, I

    2005-04-01

    Thermophilic anaerobic digestion presents an advantageous way for stabilization of sludge from wastewater treatment plants. Two different strategies for changing operational process temperature from mesophilic (37 degrees C) to thermophilic (55 degrees C) were tested using two continuous flow stirred tank reactors operated at constant organic loading rate of 1.38 g VS/l reactor/day and hydraulic retention time of 20 days. In reactor A, the temperature was increased step-wise: 37 degrees C-->42 degrees C-->47 degrees C-->51 degrees C-->55 degrees C. While in reactor B, the temperature was changed in one-step, from 37 degrees C to the desired temperature of 55 degrees C, The results showed that the overall adaptation of the process for the step-wise temperature increment took 70 days in total and a new change was applied when the process was stabilized as indicated by stable methane production and low volatile fatty acids concentrations. Although the one-step temperature increase caused a severe disturbance in all the process parameters, the system reached a new stable operation after only 30 days indicating that this strategy is the best in changing from mesophilic to thermophilic operation in anaerobic digestion plants.

  1. Thermophilic anaerobic digestion to increase the net energy balance of corn grain ethanol.

    PubMed

    Agler, Matthew T; Garcia, Marcelo L; Lee, Eric S; Schlicher, Martha; Angenent, Largus T

    2008-09-01

    U.S. production of fuel ethanol from corn grain has increased considerably over the last 10 years. Intense debate regarding the true environmental impact of the overall production process has been ongoing. The present study evaluated the utilization of thin stillage (a major byproduct of the dry-mill corn grain-to-ethanol process) in laboratory-scale thermophilic anaerobic sequencing batch reactors for conversion to methane. We found that augmentation of cobalt as a growth factor to the thermophilic anaerobic digestion process is required. After reaching sustainable operating performances, the methane potential in the reactors was 0.254 L CH4/g total chemical oxygen demand (TCOD) fed. Together with a reduction in the mass of solids that needs drying, methane generation translates to a 51% reduction of natural gas consumption at a conventional dry mill, which improves the net energy balance ratio from 1.26 to 1.70. At the design hydraulic retention time of 10 days, the digesters achieved TCOD, biodegradable COD, volatile solids, and total solids removal efficiencies of 90%, 75%, 89%, and 81%, respectively. We also found that struvite precipitation occurred in the thermophilic digesters during the course of the study, resulting in possibilities for nutrient recovery.

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

    PubMed Central

    Wu, Man-Chang; Sun, Ke-Wei; Zhang, Yong

    2006-01-01

    A laboratory-scale experiment was carried out to assess the influence of temperature fluctuation on thermophilic anaerobic digestion of municipal organic solid waste (MOSW). Heating failure was simulated by decreasing temperature suddenly from 55 °C to 20 °C suddenly; 2 h time is needed for temperature decrease and recovery. Under the conditions of 8.0 g/(L·d) and 15 d respectively for MOSW load and retention time, following results were noted: (1) biogas production almost stopped and VFA (volatile fatty acid) accumulated rapidly, accompanied by pH decrease; (2) with low temperature (20 °C) duration of 1, 5, 12 and 24 h, it took 3, 11, 56 and 72 h for the thermophilic anaerobic digestion system to reproduce methane after temperature fluctuation; (3) the longer the low temperature interval lasted, the more the methanogenic bacteria would decay; hydrolysis, acidification and methanogenesis were all influenced by temperature fluctuation; (4) the thermophilic microorganisms were highly resilient to temperature fluctuation. PMID:16502503

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

    PubMed

    Wu, Man-chang; Sun, Ke-wei; Zhang, Yong

    2006-03-01

    A laboratory-scale experiment was carried out to assess the influence of temperature fluctuation on thermophilic anaerobic digestion of municipal organic solid waste (MOSW). Heating failure was simulated by decreasing temperature suddenly from 55 degrees C to 20 degrees C suddenly; 2 h time is needed for temperature decrease and recovery. Under the conditions of 8.0 g/(L.d) and 15 d respectively for MOSW load and retention time, following results were noted: (1) biogas production almost stopped and VFA (volatile fatty acid) accumulated rapidly, accompanied by pH decrease; (2) with low temperature (20 degrees C) duration of 1, 5, 12 and 24 h, it took 3, 11, 56 and 72 h for the thermophilic anaerobic digestion system to reproduce methane after temperature fluctuation; (3) the longer the low temperature interval lasted, the more the methanogenic bacteria would decay; hydrolysis, acidification and methanogenesis were all influenced by temperature fluctuation; (4) the thermophilic microorganisms were highly resilient to temperature fluctuation.

  4. Stability of antibiotics under growth conditions for thermophilic anaerobes

    SciTech Connect

    Peteranderl, R.; Shotts, E.B. Jr.; Wiegel, J. )

    1990-06-01

    It was shown that the inhibitory effect of kanamycin and streptomycin in a growing culture of Clostridium thermohydrosulfuricum JW 102 is of limited duration. To screen a large number of antibiotics, their stability during incubation under the growth conditions of thermophilic clostridia was determined at 72 and 50C by using a 0.2% yeast extract-amended prereduced mineral medium with a pH of 7.3 or 5.0. Half-lives were determined in a modified MIC test with Escherichia coli, Staphylococcus aureus, and Bacillus megaterium as indicator strains. All compounds tested were similar at the two temperatures or more stable at 50 than at 72C. The half-life (t{sub 1/2}) at pH 7.3 and 72C ranged from 3.3 h (k = 7.26 day{sup {minus}1}, where k (degradation constant) = 1/t{sub 1/2}) for ampicillin to no detectable loss of activity for kanamycin, neomycin, and other antibiotics. Apparently some compounds became more potent during incubation. A change to pH 5.0 caused some compounds to become more labile to become more stable than at pH 7.3.

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

    PubMed

    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 mgCaCO3/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)/kgVSfed, respectively). Intermittent mixing improved the retention of methanogens inside the reactor and reduced the washout effect even at low HRT (<9 days). The negative thermal balance found was influenced by the low solids content in the WAS (2.1% TS) and by the heat losses from the digester walls. The energy balance and economic analyses demonstrated the feasibility of thermophilic AD of WAS in a hypothetical full-scale system, when the heat energy could be recovered from methane in a scenario of higher solids concentration in the substrate (>5% TS). Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Inferring microbial interactions in thermophilic and mesophilic anaerobic digestion of hog waste

    PubMed Central

    Shaw, Grace Tzun-Wen; Liu, An-Chi; Weng, Chieh-Yin; Chou, Chu-Yang

    2017-01-01

    Anaerobic digestion (AnD) is a microbiological process that converts organic waste materials into biogas. Because of its high methane content, biogas is a combustible energy source and serves as an important environmental technology commonly used in the management of animal waste generated on large animal farms. Much work has been done on hardware design and process engineering for the generation of biogas. However, little is known about the complexity of the microbiology in this process. In particular, how microbes interact in the digester and eventually breakdown and convert organic matter into biogas is still regarded as a “black box.” We used 16S rRNA sequencing as a tool to study the microbial community in laboratory hog waste digesters under tightly controlled conditions, and systematically unraveled the distinct interaction networks of two microbial communities from mesophilic (MAnD) and thermophilic anaerobic digestion (TAnD). Under thermophilic conditions, the well-known association between hydrogen-producing bacteria, e.g., Ruminococcaceae and Prevotellaceae, and hydrotrophic methanogens, Methanomicrobiaceae, was reverse engineered by their interactive topological niches. The inferred interaction network provides a sketch enabling the determination of microbial interactive relationships that conventional strategy of finding differential taxa was hard to achieve. This research is still in its infancy, but it can help to depict the dynamics of microbial ecosystems and to lay the groundwork for understanding how microorganisms cohabit in the anaerobic digester. PMID:28732056

  7. Conventional mesophilic vs. thermophilic anaerobic digestion: a trade-off between performance and stability?

    PubMed

    Labatut, Rodrigo A; Angenent, Largus T; Scott, Norman R

    2014-04-15

    A long-term comparative study using continuously-stirred anaerobic digesters (CSADs) operated at mesophilic and thermophilic temperatures was conducted to evaluate the influence of the organic loading rate (OLR) and chemical composition on process performance and stability. Cow manure was co-digested with dog food, a model substrate to simulate a generic, multi-component food-like waste and to produce non-substrate specific, composition-based results. Cow manure and dog food were mixed at a lower - and an upper co-digestion ratio to produce a low-fiber, high-strength substrate, and a more recalcitrant, lower-strength substrate, respectively. Three increasing OLRs were evaluated by decreasing the CSADs hydraulic retention time (HRT) from 20 to 10 days. At longer HRTs and lower manure-to-dog food ratio, the thermophilic CSAD was not stable and eventually failed as a result of long-chain fatty acid (LCFA) accumulation/degradation, which was triggered by the compounded effects of temperature on reaction rates, mixing intensity, and physical state of LCFAs. At shorter HRTs and upper manure-to-dog food ratio, the thermophilic CSAD marginally outperformed the biomethane production rates and substrate stabilization of the mesophilic CSAD. The increased fiber content relative to lipids at upper manure-to-dog food ratios improved the stability and performance of the thermophilic process by decreasing the concentration of LCFAs in solution, likely adsorbed onto the manure fibers. Overall, results of this study show that stability of the thermophilic co-digestion process is highly dependent on the influent substrate composition, and particularly for this study, on the proportion of manure to lipids in the influent stream. In contrast, mesophilic co-digestion provided a more robust and stable process regardless of the influent composition, only with marginally lower biomethane production rates (i.e., 7%) for HRTs as short as 10 days (OLR = 3 g VS/L-d). Copyright © 2014

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

    PubMed

    Balk, Melike; Weijma, Jan; Stams, Alfons J M

    2002-07-01

    A novel, anaerobic, non-spore-forming, mobile, Gram-negative, thermophilic bacterium, strain TMOT, was isolated from a thermophilic sulfate-reducing bioreactor operated at 65 C with methanol as the sole substrate. The G+C content of the DNA of strain TMOT was 39.2 mol%. The optimum pH, NaCl concentration, and temperature for growth were 7.0, 1.0%, and 65 degrees C, respectively. Strain TMOT was able to degrade methanol to CO2 and H2 in syntrophic culture with Methanothermobacter thermautotrophicus AH or Thermodesulfovibrio yellowstonii. Thiosulfate, elemental sulfur, Fe(III) and anthraquinone-2,6-disulfonate were able to serve as electron acceptors during methanol degradation. In the presence of thiosulfate or elemental sulfur, methanol was converted to CO2 and partly to alanine. In pure culture, strain TMOT was also able to ferment methanol to acetate, CO2 and H2. However, this degradation occurred slower than in syntrophic cultures or in the presence of electron acceptors. Yeast extract was required for growth. Besides growing on methanol, strain TMOT grew by fermentation on a variety of carbohydrates including monomeric and oligomeric sugars, starch and xylan. Acetate, alanine, CO2, H2, and traces of ethanol, lactate and alpha-aminobutyrate were produced during glucose fermentation. Comparison of 16S rDNA genes revealed that strain TMOT is related to Thermotoga subterranea (98%) and Thermotoga elfii (98%). The type strain is TMOT (= DSM 14385T = ATCC BAA-301T). On the basis of the fact that these organisms differ physiologically from strain TMOT, it is proposed that strain TMOT be classified as a new species, within the genus Thermotoga, as Thermotoga lettingae.

  9. [Isolation, identification and enzyme characterization of a thermophilic cellulolytic anaerobic bacterium].

    PubMed

    Zhao, Yinping; Ma, Shichun; Sun, Yingjie; Huang, Yan; Deng, Yu

    2012-09-04

    To identify a thermophilic bacterium from horse manure to degrade cellulose efficiently, and to enrich microbial resources producing cellulolytic ethanol by co-culturing with thermophilic ethanol producing bacterium. We used Hungate anaerobic technique to isolate a strain named as HCp from horse manure mixed culture; its phylogeny was identified through 16S rDNA sequencing. Enzymatic assays were determined using DNS method. The isolated HCp cells were straight with rods size of(0.35-0.50) microm x (2.42-6.40) microm, in the form of single or paring. This strain belongs to a strictly anaerobic Gram-negative bacterium, it is able to form spores, shows motile ability and resistance to neomycin. The strain could degrade filter paper cellulose, cellulose powder, microcrystalline cellulose, cotton wool, rice straw and gelatin, and it was also able to utilize abundant saccharides as substrates such as cellobiose, glucose, xylose, xylan, raffinose, maltose, sorbose, fructose and galactose. The growth pH ranges from 6.5 to 8.5, temperature from 35 to 70 degrees C and concentration of NaCl on cellulose from 0% to 1.0%, while the optima of pH 6.85, 60 degreesC and 0.2% NaCl. Under the optimal growth conditions, the filter paper cellulose degradation rate was up to 90.40% after 10 days. The optimum temperatures for FPA, CMCase, beta-glucosidase and xylanase were 70 degrees C, 70 degrees C, 70 degrees C, and 60 degrees C respectively. CMCase activity was found with high thermal stability. The phylogenetic analysis based on partial 16S rDNA revealed that HCp was close to Acetivibrio cellulolyticus and A. cellulosolvens with 97.5% sequence similarities. Strain HCp is thermophilic, efficiently cellulolytic anaerobe. It is able to utilize vast substrates and produce highly thermostable enzymes. It is a potential bacterium that can be used for cellulolytic ethanol production.

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

    PubMed

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

    2015-01-01

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

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

    PubMed

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

    2015-05-01

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

  12. Escherichia coli inactivation kinetics in anaerobic digestion of dairy manure under moderate, mesophilic and thermophilic temperatures

    PubMed Central

    2011-01-01

    Batch anaerobic digestion experiments using dairy manure as feedstocks were performed at moderate (25°C), mesophilic (37°C), and thermophilic (52.5°C) temperatures to understand E. coli, an indicator organism for pathogens, inactivation in dairy manure. Incubation periods at 25, 37, and 52.5°C, were 61, 41, and 28 days respectively. Results were used to develop models for predicting E. coli inactivation and survival in anaerobic digestion. For modeling we used the decay of E. coli at each temperature to calculate the first-order inactivation rate coefficients, and these rates were used to formulate the time - temperature - E. coli survival relationships. We found the inactivation rate coefficient at 52.5°C was 17 and 15 times larger than the inactivation rate coefficients at 25 and 37°C, respectively. Decimal reduction times (D10; time to achieve one log removal) at 25, 37, and 52.5°C, were 9 -10, 7 - 8 days, and < 1 day, respectively. The Arrhenius correlation between inactivation rate coefficients and temperatures over the range 25 -52.5°C was developed to understand the impacts of temperature on E. coli inactivation rate. Using this correlation, the time - temperature - E. coli survival relationships were derived. Besides E. coli inactivation, impacts of temperature on biogas production, methane content, pH change, ORP, and solid reduction were also studied. At higher temperatures, biogas production and methane content was greater than that at low temperatures. While at thermophilic temperature pH was increased, at mesophilic and moderate temperatures pH were reduced over the incubation period. These results can be used to understand pathogen inactivation during anaerobic digestion of dairy manure, and impacts of temperatures on performance of anaerobic digesters treating dairy manure. PMID:21906374

  13. Description of a new anaerobic thermophilic bacterium, Thermoanaerobacterium butyriciformans sp. nov.

    PubMed

    López, G; Cañas-Duarte, S J; Pinzón-Velasco, A M; Vega-Vela, N E; Rodríguez, M; Restrepo, S; Baena, S

    2017-03-01

    Strain USBA-019(T), an anaerobic and thermophilic strain, was identified as a new member of the genus Thermoanaerobacterium. USBA-019(T) cells are gram-positive, strictly anaerobic, thermophilic, chemoorganotrophic, moderately acidophilic, non-motile, endospore-forming, slightly curved, and rod-shaped. Cells measure 0.4×3.0-7.0μm. Optimal growth occurs at 50-55°C (35-65°C). Optimum pH is 5.0-5.5 (4.0-8.5). Thiosulfate, elemental sulfur and nitrate were utilized as electron acceptors. Fermentation of glucose, lactose, cellobiose, galactose, arabinose, xylose, starch and xylan primarily produced acetate and butyrate. Xylan, starch and cellobiose produced ethanol and starch, cellobiose, galactose, arabinose and mannose produced lactic acid. Phylogenetic analyses based on 16S rRNA gene sequence comparison and genomic relatedness indices show the close relation of USBA-019(T) to Thermoanaerobacterium thermostercoris and Thermoanaerobacterium aotearoense (similarity value: 99%). Hybridization of USBA-019(T), Th. thermostercoris DSM22141(T) and Th. aotearoense DMS10170(T) found DNA-DNA relatedness of 33.2% and 18.2%, respectively. Based on phenotypic, chemotaxonomic and phylogenetic evidence, along with low identity at whole genome level, USBA-019(T) is a novel species of the genus Thermoanaerobacterium which we propose to name Thermoanaerobacterium butyriciformans sp. nov. The type strain is USBA-019(T) (=CMPUJ U-019(T)=DSM 101588(T)).

  14. Treatment of spent wash in anaerobic thermophilic suspended growth reactor (ATSGR).

    PubMed

    Banu, Rajesh; Kaliappan, S; Beck, Dieter

    2007-04-01

    Pollution through spent wash is a major problem in India. There is an urgent need to develop wastewater treatment technologies for safer disposal. In the present investigation, an attempt has been made to examine a few aspects of thermophilic anaerobic digestion of spent wash collected from a distillery. The study was carried out in a 4 liter laboratory scale anaerobic thermophilic suspended growth reactor After the successful startup, the organic loading was increased stepwise to assess the performance of the reactor. During the study period, biogas generated was recorded and the maximum gas generated was found to be 11.9 liter at an organic loading rate (OLR) of 29 g COD/l. A 500% increase in the volatile fatty acid (VFA) concentration (1850 mg/l) was observed, when the OLR was increased from 29 to 30 g COD/l. During the souring phase the removal of COD, total solids (TS) and volatile solids (VS) were in the order of 52%, 40% and 46% respectively The methane content in the biogas varied from 65% to 75%.

  15. Mesophilic versus thermophilic anaerobic digestion of cattle manure: methane productivity and microbial ecology

    PubMed Central

    Moset, Veronica; Poulsen, Morten; Wahid, Radziah; Højberg, Ole; Møller, Henrik Bjarne

    2015-01-01

    In this study, productivity and physicochemical and microbiological (454 sequencing) parameters, as well as environmental criteria, were investigated in anaerobic reactors to contribute to the ongoing debate about the optimal temperature range for treating animal manure, and expand the general knowledge on the relation between microbiological and physicochemical process indicators. For this purpose, two reactor sizes were used (10 m3 and 16 l), in which two temperature conditions (35°C and 50°C) were tested. In addition, the effect of the hydraulic retention time was evaluated (16 versus 20 days). Thermophilic anaerobic digestion showed higher organic matter degradation (especially fiber), higher pH and higher methane (CH4) yield, as well as better percentage of ultimate CH4 yield retrieved and lower residual CH4 emission, when compared with mesophilic conditions. In addition, lower microbial diversity was found in the thermophilic reactors, especially for Bacteria, where a clear intensification towards Clostridia class members was evident. Independent of temperature, some similarities were found in digestates when comparing with animal manure, including low volatile fatty acids concentrations and a high fraction of Euryarchaeota in the total microbial community, in which members of Methanosarcinales dominated for both temperature conditions; these indicators could be considered a sign of process stability. PMID:25737010

  16. Net energy production associated with pathogen inactivation during mesophilic and thermophilic anaerobic digestion of sewage sludge.

    PubMed

    Ziemba, Christopher; Peccia, Jordan

    2011-10-15

    The potential for anaerobic digester energy production must be balanced with the sustainability of reusing the resultant biosolids for land application. Mesophilic, thermophilic, temperature-phased, and high temperature (60 or 70 °C) batch pre-treatment digester configurations have been systematically evaluated for net energy production and pathogen inactivation potential. Energy input requirements and net energy production were modeled for each digester scheme. First-order inactivation rate coefficients for Escherichia coli, Enterococcus faecalis and bacteriophage MS-2 were measured at each digester temperature and full-scale pathogen inactivation performance was estimated for each indicator organism and each digester configuration. Inactivation rates were found to increase dramatically at temperatures above 55 °C. Modeling full-scale performance using retention times based on U.S. EPA time and temperature constraints predicts a 1-2 log inactivation in mesophilic treatment, and a 2-5 log inactivation in 50-55 °C thermophilic and temperature-phased treatments. Incorporating a 60 or 70 °C batch pre-treatment phase resulted in dramatically higher potency, achieving MS-2 inactivation of 14 and 16 logs respectively, and complete inactivation (over 100 log reduction) of E. coli and E. faecalis. For temperatures less than 70 °C, viability staining of thermally-treated E. coli showed significantly reduced inactivation relative to standard culture enumeration. Due to shorter residence times in thermophilic reactors, the net energy production for all digesters was similar (less than 20% difference) with the 60 or 70 °C batch treatment configurations producing the most net energy and the mesophilic treatment producing the least. Incorporating a 60 or 70 °C pre-treatment phase can dramatically increase pathogen inactivation performance without decreasing net energy capture from anaerobic digestion. Energy consumption is not a significant barrier against

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

    PubMed

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

    2013-12-01

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

  18. Thermophilic two-stage dry anaerobic digestion of model garbage with ammonia stripping.

    PubMed

    Yabu, Hironori; Sakai, Chikako; Fujiwara, Tomoko; Nishio, Naomichi; Nakashimada, Yutaka

    2011-03-01

    To avoid the inhibition of methane production by ammonia that occurs during the degradation of garbage, anaerobic digestion with prior ammonia production and subsequent stripping was investigated. In the ammonia production phase, the maximum ammonia concentration was approximately 2800 mg N/kg of total wet sludge in the range of 4 days of sludge retention time, indicating that only 43% of total nitrogen in the model garbage was converted to ammonia. The model garbage from which ammonia was produced and stripped was subjected to semi-continuous thermophilic dry anaerobic digestion over 180 days. The gas yield was in the range of 0.68 to 0.75 Nm(3)/kg volatile solid, and it decreased with the decrease of the sludge retention time. The ammonia-nitrogen concentration in the sludge was kept below 3000 mg N/kg total wet sludge. Microbial community structure analysis revealed that the phylum Firmicutes dominated in the ammonia production, but the community structure changed at different sludge retention times. In dry anaerobic digestion, the dominant bacteria shifted from the phylum Thermotogae to Firmicutes. The dominant archaeon was the genus Methanothermobacter, but the ratio of Methanosarcina increased during the process of dry anaerobic digestion.

  19. A study of two-stage anaerobic digestion of solid potato waste using reactors under mesophilic and thermophilic conditions.

    PubMed

    Parawira, W; Murto, M; Read, J S; Mattiasson, B

    2007-11-01

    A two-stage anaerobic digestion process operated under mesophilic and thermophilic conditions was investigated for the treatment of solid potato waste to determine optimal methane yield, efficiency of operation and process stability. A solid-bed reactor was used for hydrolysis/acidification stage while an upflow anaerobic sludge blanket (UASB) reactor was used in the second stage, for methanogenesis. Three sets of conditions were investigated: (1) mesophilic + mesophilic, (II) mesophilic + thermophilic and (III) thermophilic + thermophilic in the hydrolysis/acidification and methanogenesis reactors, respectively. The methane yield was higher under mesophilic conditions (0.49 l CH4 g COD(-1)degraded) than thermophilic conditions (0.41 l CH4 g COD(-1)degraded) with reference to the methanogenic reactors. (COD)--chemical oxygen demand. However, the digestion period was shorter in systems II and III than in system I. Also, in system III the UASB reactor (thermophilic conditions) could handle a higher organic loading rate (OLR) (36 g COD 1(-1)d(-1)) than in system I (11 g COD 1(-1)d(-1)) (mesophilic conditions) with stable operation. Higher OLRs in the methanogenic reactors resulted in reactor failure due to increasing total volatile fatty acid levels. In all systems, the concentration of propionate was one of the highest, higher than acetic acid, among the volatile fatty acids in the effluent. The results show the feasibility of using a two-stage system to treat solid potato waste under both mesophilic and thermophilic conditions. If the aim is to treat solid potato waste completely within a short period of time thermophilic conditions are to be preferred, but to obtain higher methane yield mesophilic conditions are preferable and therefore there is a need to balance methane yield and complete digestion period when dealing with large quantities of solid potato waste.

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

    SciTech Connect

    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.

  1. High-solids anaerobic mono-digestion of riverbank grass under thermophilic conditions.

    PubMed

    Andriamanohiarisoamanana, Fetra J; Matsunami, Nobuyuki; Yamashiro, Takaki; Iwasaki, Masahiro; Ihara, Ikko; Umetsu, Kazutaka

    2017-02-01

    The purpose of this study was to investigate the potential of high-solids anaerobic mono-digestion of riverbank grass under thermophilic conditions, focusing on the effects of the strength and the amount of inoculum. Ensiled grass was inoculated with three different inocula; inoculum from liquid anaerobic digester (LI), inoculum from dry anaerobic digester (DI), and mixture of LI and DI (MI), at feedstock-to-inoculum ratio (FIR) of 1, 2 and 4. The ensiling process of riverbank grass reduced moisture content (p>0.05), while the hemicellulose content was significantly increased from 30.88% to 35.15% (p<0.05), on dry matter basis. The highest methane production was at an FIR of 2 with MI (167L/kg VSadded), which was significantly higher (p<0.05) than with DI, but not significant compared to LI (p>0.05). At an FIR of 4, digesters inoculated with LI and DI failed to produce methane, whereas 135LCH4/kg VSadded was obtained with MI. The kinetic studies showed that at an FIR of 1 with LI and MI, the inoculum had less of effects on the hydrolysis rate constant (0.269day(-1) and 0.245day(-1)) and methane production (135 versus 149L/kg VSadded); rather, it affected the lag phase. In a thermophilic HS-AD of riverbank grass, the mixture of inoculum with low and high total solids content (TS) helps increase the TS of inoculum and digestion process. An FIR of 2 was deducted to be the limit for a better startup time and higher volumetric productivity of methane. Copyright © 2016. Published by Elsevier B.V.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed Central

    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

  4. Ultrasound-Mediated DNA Transformation in Thermophilic Gram-Positive Anaerobes

    PubMed Central

    Ji, Yuetong; He, Zhili; Pu, Yunting; Zhou, Jizhong; Xu, Jian

    2010-01-01

    Background Thermophilic, Gram-positive, anaerobic bacteria (TGPAs) are generally recalcitrant to chemical and electrotransformation due to their special cell-wall structure and the low intrinsic permeability of plasma membranes. Methodology/Principal Findings Here we established for any Gram-positive or thermophiles an ultrasound-based sonoporation as a simple, rapid, and minimally invasive method to genetically transform TGPAs. We showed that by applying a 40 kHz ultrasound frequency over a 20-second exposure, Texas red-conjugated dextran was delivered with 27% efficiency into Thermoanaerobacter sp. X514, a TGPA that can utilize both pentose and hexose for ethanol production. Experiments that delivered plasmids showed that host-cell viability and plasmid DNA integrity were not compromised. Via sonoporation, shuttle vectors pHL015 harboring a jellyfish gfp gene and pIKM2 encoding a Clostridium thermocellum β-1,4-glucanase gene were delivered into X514 with an efficiency of 6×102 transformants/µg of methylated DNA. Delivery into X514 cells was confirmed via detecting the kanamycin-resistance gene for pIKM2, while confirmation of pHL015 was detected by visualization of fluorescence signals of secondary host-cells following a plasmid-rescue experiment. Furthermore, the foreign β-1,4-glucanase gene was functionally expressed in X514, converting the host into a prototypic thermophilic consolidated bioprocessing organism that is not only ethanologenic but cellulolytic. Conclusions/Significance In this study, we developed an ultrasound-based sonoporation method in TGPAs. This new DNA-delivery method could significantly improve the throughput in developing genetic systems for TGPAs, many of which are of industrial interest yet remain difficult to manipulate genetically. PMID:20838444

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

    PubMed

    Chi, Yongzhi; Li, Yuyou; Fei, Xuening; Wang, Shaopo; Yuan, Hongying

    2011-01-01

    Abstract Pretreatment of thickened waste activated sludge (TWAS) by combined microwave and alkaline pretreatment (MAP) was studied to improve thermophilic anaerobic digestion efficiency. Uniform design was applied to determine the combination of target temperature (11 degrees-210 degrees C), microwave holding time (1-51 min), and NaOH dose (0-2.5 g NaOH/g suspended solids (SS)) in terms of their effect on volatile suspended solids (VSS) solubilization. Maximum solubilization ratio (85.1%) of VSS was observed at 210 degrees C with 0.2 g-NaOH/g-SS and 35 min holding time. The effects of 12 different pretreatment methods were investigated in 28 thermophilic batch reactors by monitoring cumulative methane production (CMP). Improvements in methane production in the TWAS were directly related to the microwave and alkaline pretreatment of the sludge. The highest CMP was a 27% improvement over the control. In spite of the increase in soluble chemical oxygen demand concentration and the decrease in dewaterability of digested sludge, a semi-continuous thermophilic reactor fed with pretreated TWAS without neutralization (at 170 degrees C with 1 min holding time and 0.05 g NaOH/g SS) was stable and functioned well, with volatile solid (VS) and total chemical oxygen demand (TCOD) reductions of 28% and 18%, respectively, which were higher than those of the control system. Additionally, methane yields (L@STP/g-CODadded, at standard temperature and pressure (STP) conditions of 0 degree C and 101.325 kPa) and (L@STP/g VSadded) increased by 17% and 13%, respectively, compared to the control reactor.

  6. High-efficiency hydrogen production by an anaerobic, thermophilic enrichment culture from an Icelandic hot spring.

    PubMed

    Koskinen, Perttu E P; Lay, Chyi-How; Puhakka, Jaakko A; Lin, Ping-Jei; Wu, Shu-Yii; Orlygsson, Jóhann; Lin, Chiu-Yue

    2008-11-01

    Dark fermentative hydrogen production from glucose by a thermophilic culture (33HL), enriched from an Icelandic hot spring sediment sample, was studied in two continuous-flow, completely stirred tank reactors (CSTR1, CSTR2) and in one semi-continuous, anaerobic sequencing batch reactor (ASBR) at 58 degrees C. The 33HL produced H2 yield (HY) of up to 3.2 mol-H2/mol-glucose along with acetate in batch assay. In the CSTR1 with 33HL inoculum, H2 production was unstable. In the ASBR, maintained with 33HL, the H2 production enhanced after the addition of 6 mg/L of FeSO4 x H2O resulting in HY up to 2.51 mol-H2/mol-glucose (H2 production rate (HPR) of 7.85 mmol/h/L). The H2 production increase was associated with an increase in butyrate production. In the CSTR2, with ASBR inoculum and FeSO4 supplementation, stable, high-rate H2 production was obtained with HPR up to 45.8 mmol/h/L (1.1 L/h/L) and HY of 1.54 mol-H2/mol-glucose. The 33HL batch enrichment was dominated by bacterial strains closely affiliated with Thermobrachium celere (99.8-100%). T. celere affiliated strains, however, did not thrive in the three open system bioreactors. Instead, Thermoanaerobacterium aotearoense (98.5-99.6%) affiliated strains, producing H2 along with butyrate and acetate, dominated the reactor cultures. This culture had higher H2 production efficiency (HY and specific HPR) than reported for mesophilic mixed cultures. Further, the thermophilic culture readily formed granules in CSTR and ASBR systems. In summary, the thermophilic culture as characterized by high H2 production efficiency and ready granulation is considered very promising for H2 fermentation from carbohydrates.

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

    PubMed

    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.

  8. Transition of municipal sludge anaerobic digestion from mesophilic to thermophilic and long-term performance evaluation.

    PubMed

    Tezel, Ulas; Tandukar, Madan; Hajaya, Malek G; Pavlostathis, Spyros G

    2014-10-01

    Strategies for the transition of municipal sludge anaerobic digestion from mesophilic to thermophilic were assessed and the long-term stability and performance of thermophilic digesters operated at a solids retention time of 30days were evaluated. Transition from 36°C to 53.3°C at a rate of 3°C/day resulted in fluctuation of the daily gas and volatile fatty acids (VFAs) production. Steady-state was reached within 35days from the onset of temperature increase. Transitions from either 36 or 53.3°C to 60°C resulted in relatively stable daily gas production, but VFAs remained at very high levels (in excess of 5000mg COD/L) and methane production was lower than that of the mesophilic reactor. It was concluded that in order to achieve high VS and COD destruction and methane production, the temperature of continuous-flow, suspended growth digesters fed with mixed municipal sludge should be kept below 60°C.

  9. Effect of fillers on key characteristics of sludge thermophilic anaerobic digestion.

    PubMed

    Shao, Liming; Xu, Yuanshun; Wang, Tianfeng; Lü, Fan; He, Pinjing

    2015-10-01

    In anaerobic digestion (AD) of sludge, AD efficiency and digested sludge (DS) dewaterability are critical factors. In this study, polyester non-woven fabric fillers were integrated into a sludge digester. The effect of such fillers on digestion was investigated in thermophilic temperature range in semi-continuous mode. Methane production of filler system and control reactor were significantly different (P < 0.05, paired t-test). At hydraulic retention times of 18 days and 12 days, the corresponding methane yields from filler system were 140% and 161%, respectively, of the yields from control digester without filler. Improvement of DS dewaterability was uncertain during 110 days of operation. While after a longer period of digestion, filler system resulted in a lower normalized capillary suction time of DS (76.5 ± 21.6 s L/g total suspended solids) than control reactor (118.7 ± 32.9 s L/g total suspended solids). The results showed that the filler could improve thermophilic AD performance, except at too short hydraulic retention times. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Development of bioconcrete material using an enrichment culture of novel thermophilic anaerobic bacteria.

    PubMed

    Ghosh, P; Mandal, S; Pal, S; Bandyopadhyaya, G; Chattopadhyay, B D

    2006-04-01

    In the biosphere, bacteria can function as geo-chemical agents, promoting the dispersion, fractionation and/or concentration of materials. Microbial mineral precipitation is resulted from metabolic activities of microorganisms. Based on this biomineralogy concept, an attempt has been made to develop bioconcrete material incorporating of an enrichment culture of thermophilic and anaerobic bacteria within cement-sand mortar/concrete. The results showed a significant increase in compressive strength of both cement-sand mortar and concrete due to the development of filler material within the pores of cement sand matrix. Maximum strength was observed at concentration 10(5)cell/ml of water used in mortar/concrete. Addition of Escherichia coil or media composition on mortar showed no such improvement in strength.

  11. Reactor performance and microbial community dynamics during solid-state anaerobic digestion of corn stover at mesophilic and thermophilic conditions.

    PubMed

    Shi, Jian; Wang, Zhongjiang; Stiverson, Jill A; Yu, Zhongtang; Li, Yebo

    2013-05-01

    Reactor performance and microbial community dynamics were investigated during solid state anaerobic digestion (SS-AD) of corn stover at mesophilic and thermophilic conditions. Thermophilic SS-AD led to faster and greater reductions of cellulose and hemicelluloses during the first 12 days compared to mesophilic SS-AD. However, accumulation of volatile fatty acids (VFAs) was 5-fold higher at thermophilic than mesophilic temperatures, resulting in a large pH drop during days 6-12 in the thermophilic reactors. Culture-based enumeration revealed 10-50 times greater populations of cellulolytic and xylanolytic microbes during thermophilic SS-AD than mesophilic SS-AD. DGGE analysis of PCR amplified 16S rRNA genes showed dynamic shifts, especially during the thermophilic SS-AD, of bacterial and archaeal communities over the 38 days of SS-AD as a result of acclimation of the initial seed microbial consortia to the lignocellulosic feedstock. The findings of this study can guide future studies to improve efficiency and stability of SS-AD. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Bacterial community structure in treated sewage sludge with mesophilic and thermophilic anaerobic digestion.

    PubMed

    Stiborova, Hana; Wolfram, Jan; Demnerova, Katerina; Macek, Tomas; Uhlik, Ondrej

    2015-11-01

    Stabilized sewage sludge is applied to agricultural fields and farmland due to its high organic matter content. The aim of this study was to investigate the effects of two types of sludge stabilization, mesophilic anaerobic digestion (MAD) and thermophilic anaerobic digestion (TAD), on bacterial communities in sludge, including the presence of pathogenic microorganisms. Bacterial community structure and phylogenetic diversity were analyzed in four sewage sludge samples from the Czech Republic. Analysis of 16S ribosomal RNA (rRNA) genes showed that investigated sludge samples harbor diverse bacterial populations with only a few taxa present across all samples. Bacterial diversity was higher in sludge samples after MAD versus TAD treatment, and communities in MAD-treated sludge shared the highest genetic similarities. In all samples, the bacterial community was dominated by reads affiliated with Proteobacteria. The sludge after TAD treatment had considerably higher number of reads of thermotolerant/thermophilic taxa, such as the phyla Deinococcus-Thermus and Thermotogae or the genus Coprothermobacter. Only one operational taxonomic unit (OTU), which clustered with Rhodanobacter, was detected in all communities at a relative abundance >1 %. All of the communities were screened for the presence of 16S rRNA gene sequences of pathogenic bacteria using a database of 122 pathogenic species and ≥98 % identity threshold. The abundance of such sequences ranged between 0.23 and 1.57 % of the total community, with lower numbers present after the TAD treatment, indicating its higher hygienization efficiency. Sequences clustering with nontuberculous mycobacteria were present in all samples. Other detected sequences of pathogenic bacteria included Streptomyces somaliensis, Acinetobacter calcoaceticus, Alcaligenes faecalis, Gordonia spp., Legionella anisa, Bordetella bronchiseptica, Enterobacter aerogenes, Brucella melitensis, and Staphylococcus aureus.

  13. Screening of thermophilic anaerobic bacteria for solid substrate cultivation on lignocellulosic substrates.

    PubMed

    Chinn, Mari S; Nokes, Sue E; Strobel, Herbert J

    2006-01-01

    Interest in solid substrate cultivation (SSC) techniques is gaining for biochemical production from renewable resources; however, heat and mass transfer problems may limit application of this technique. The use of anaerobic thermophiles in SSC offers a unique solution to overcoming these challenges. The production potential of nine thermophilic anaerobic bacteria was examined on corn stover, sugar cane bagasse, paper pulp sludge, and wheat bran in submerged liquid cultivation (SmC) and SSC. Production of acetate, ethanol, and lactate was measured over a 10 day period, and total product concentrations were used to compare the performance of different organism-substrate combinations using the two cultivation methods. Overall microbial activity in SmC and SSC was dependent on the organism and growth substrate. Clostridium thermocellum strains JW20, LQRI, and 27405 performed significantly better in SSC when grown on sugar cane bagasse and paper pulp sludge, producing at least 70 and 170 mM of total products, respectively. Growth of C. thermocellum strains in SSC on paper pulp sludge proved to be most favorable, generating at least twice the concentration of total products produced in SmC (p-value < 0.05). Clostridium thermolacticum TC21 demonstrated growth on all substrates producing 30-80 and 60-116 mM of total product in SmC and SSC, respectively. Bacterial species with optimal growth temperatures of 70 degrees C grew best on wheat bran in SmC, producing total product concentrations of 45-75 mM. For some of the organism-substrate combinations total end product concentrations in SSC exceeded those in SmC, indicating that SSC may be a promising alternative for microbial activity and value-added biochemical production.

  14. Gelria glutamica gen. nov., sp. nov., a thermophilic, obligately syntrophic, glutamate-degrading anaerobe.

    PubMed

    Plugge, Caroline M; Balk, Melike; Zoetendal, Erwin G; Stams, Alfons J M

    2002-03-01

    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 and non-motile. The optimal temperature for growth was 50-55 degrees C and growth occurred between 37 and 60 degrees C. The pH range for growth was 5.5-8 with optimum growth at pH 7. In pure culture, strain TGO(T) could grow on pyruvate, lactate, glycerol and several sugars. In co-culture with the hydrogenotrophic methanogen Methanobacterium thermautotrophicum strain Z-245, strain TGO(T) could grow on glutamate, proline and Casamino acids. Glutamate was converted to H2, CO2, propionate and traces of succinate. Strain TGO(T) was not able to utilize sulphate, sulphite, thiosulphate, nitrate or fumarate as electron acceptors. The G+C content was 33.8 mol%. Sequence analysis of the 16S rDNA revealed that strain TGO(T) belongs to the thermophilic, endospore-forming anaerobes, though no close relations were found. Its closest relations were Moorella glycerini (92%) and Moorella thermoacetica (90%). Strain TGOT had an unusually long 16S rDNA of more than 1700 bp. The additional base pairs were found as long loops in the V1, V7 and V9 regions of the 16S rDNA. However, the loops were not found in the 16S rRNA. The name Gelria glutamica gen. nov., sp. nov. is proposed for strain TGO(T).

  15. Effect of limited air exposure and comparative performance between thermophilic and mesophilic solid-state anaerobic digestion of switchgrass.

    PubMed

    Sheets, Johnathon P; Ge, Xumeng; Li, Yebo

    2015-03-01

    Switchgrass is an attractive feedstock for biogas production via anaerobic digestion (AD). Many studies have used switchgrass for liquid anaerobic digestion (L-AD), but few have used switchgrass for solid-state anaerobic digestion (SS-AD). Limited air exposure to the reactor headspace has been adopted in commercial scale anaerobic digesters for different applications. However, little research has examined the effect of limited air exposure on biogas production during SS-AD. In this study, the effects of air exposure and total solids (TS) content on SS-AD performance were evaluated under mesophilic (36±1°C) and thermophilic (55±0.3°C) conditions. Limited air exposure did not significantly influence the methane yield during SS-AD. Thermophilic SS-AD had greater methane yields (102-145LCH4kg(-1)VSadded) than mesophilic SS-AD (88-113LCH4kg(-1)VSadded). Both mesophilic SS-AD (73-136GJ) and thermophilic SS-AD (2-95GJ) produced positive net energy based on a theoretical 'garage-type' SS-AD digester operating in a temperate climate. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Anaerobic Growth, a Property Horizontally Transferred by an Hfr-Like Mechanism among Extreme Thermophiles

    PubMed Central

    Ramírez-Arcos, Sandra; Fernández-Herrero, Luis A.; Marín, Irma; Berenguer, José

    1998-01-01

    Despite the fact that the extreme thermophilic bacteria belonging to the genus Thermus are classified as strict aerobes, we have shown that Thermus thermophilus HB8 (ATCC 27634) can grow anaerobically when nitrate is present in the growth medium. This strain-specific property is encoded by a respiratory nitrate reductase gene cluster (nar) whose expression is induced by anoxia and nitrate (S. Ramírez-Arcos, L. A. Fernández-Herrero, and J. Berenguer, Biochim. Biophys. Acta, 1396:215–1997). We show here that this nar operon can be transferred by conjugation to an aerobic Thermus strain, enabling it to grow under anaerobic conditions. We show that this transfer takes place through a DNase-insensitive mechanism which, as for the Hfr (high frequency of recombination) derivatives of Escherichia coli, can also mobilize other chromosomal markers in a time-dependent way. Three lines of evidence are presented to support a genetic linkage between nar and a conjugative plasmid integrated into the chromosome. First, the nar operon is absent from a plasmid-free derivative and from a closely related strain. Second, we have identified an origin for autonomous replication (oriV) overlapping the last gene of the nar cluster. Finally, the mating time required for the transfer of the nar operon is in good agreement with the time expected if the transfer origin (oriT) were located nearby and downstream of nar. PMID:9620963

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

    PubMed

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

    2016-07-01

    Low oxygen levels (μgO2L(-1)) in anaerobic reactors are quite common and no relevant consequences are expected. On the contrary, higher concentrations could affect the process. This work aimed to study the influence of oxygen (4.3 and 8.8mgO2L(-1), respectively) on the different microbial activities (hydrolytic, acidogenic and methanogenic) of thermophilic anaerobic biomass and on the methanogenic community structure. Batch tests in presence of oxygen were conducted using specific substrates for each biological activity and a blank (with minimum oxygen) was included. No effect of oxygen was observed on the hydrolytic and acidogenic activities. In contrast, the methane production rate decreased by 40% in all oxygenated batches and the development of active archaeal community was slower in presence of 8.8mgO2L(-1). However, despite this sensitivity of methanogens to oxygen at saturation levels, the inhibition was reversible. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Influence of bicarbonate buffer on the methanogenetic pathway during thermophilic anaerobic digestion.

    PubMed

    Lin, Yucheng; Lü, Fan; Shao, Liming; He, Pinjing

    2013-06-01

    To investigate the influence of bicarbonate on the metabolic pathway of methanogenesis, different concentrations of bicarbonate (0-0.2 mol/L) were applied during thermophilic anaerobic digestion of 2.5 and 5 g/L glucose. The stable carbon isotopic results demonstrated that, as the bicarbonate concentration increased, the proportion of total CH4 generated from hydrogenotrophic methanogenesis generally increased. Furthermore, methane production rates and acetate degradation rates were seriously reduced under high levels of bicarbonate (0.15 and 0.2 mol/L). Meanwhile, carbon isotope fractionation was more prominent in treatments with 5 g/L glucose than that of 2.5 g/L glucose. Increased concentrations of bicarbonate altered the dominant methanogens and bacteria and increased the microbial diversity. The inhibitory effects of high concentrations of bicarbonate suggested that bicarbonate should be used cautiously as a buffer salt in anaerobic processes, especially when methanogenetic pathways were studied. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Single-stage, batch, leach-bed, thermophilic anaerobic digestion of spent sugar beet pulp.

    PubMed

    Koppar, Abhay; Pullammanappallil, Pratap

    2008-05-01

    Spent sugar beet pulp as received was digested in a single-stage, batch, unmixed, leach-bed, laboratory scale thermophilic anaerobic digester. Biogasification of each 0.450 kg (wet weight) batch of spent pulp was initiated by inoculating with anaerobically digested liquor from previous run. The average methane yield was 0.336 m3 CH4 at STP (kgVS)(-1), the maximum methane production rate was 0.087 m3 CH4 at STP (kgVS)(-1)d(-1), average lag time to initiate methanogenesis was only 0.44 days and time required to achieve 95% methane yield was 8 days. The pH in the digesters ranged between 8.0 and 9.5. High rates of methane generation were sustained even at high pH values. The equivalent organic loading rate in the batch digesters was 4 kgCODm(-3)d(-1). The digestion process used here offers significant improvements over one-stage and two-stage systems reported in the literature with comparable performance as it is a single-stage system where the feedstock does not require size reduction, and mixing is not required in the digester.

  20. Anaerobic Digestion of Renewable Biomass: Thermophilic Temperature Governs Methanogen Population Dynamics ▿ †

    PubMed Central

    Krakat, Niclas; Westphal, A.; Schmidt, S.; Scherer, P.

    2010-01-01

    Beet silage and beet juice were digested continuously as representative energy crops in a thermophilic biogas fermentor for more than 7 years. Fluorescence microscopy of 15 samples covering a period of 650 days revealed that a decrease in temperature from 60°C to 55°C converted a morphologically uniform archaeal population (rods) into a population of methanogens exhibiting different cellular morphologies (rods and coccoid cells). A subsequent temperature increase back to 60°C reestablished the uniform morphology of methanogens observed in the previous 60°C period. In order to verify these observations, representative samples were investigated by amplified rRNA gene restriction analysis (ARDRA) and fluorescence in situ hybridization (FISH). Both methods confirmed the temperature-dependent population shift observed by fluorescence microscopy. Moreover, all samples investigated demonstrated that hydrogenotrophic Methanobacteriales dominated in the fermentor, as 29 of 34 identified operational taxonomic units (OTUs) were assigned to this order. This apparent discrimination of acetoclastic methanogens contradicts common models for anaerobic digestion processes, such as anaerobic digestion model 1 (ADM1), which describes the acetotrophic Euryarchaeota as predominant organisms. PMID:20097828

  1. Enrichment of thermophilic syntrophic anaerobic glutamate-degrading consortia using a dialysis membrane reactor.

    PubMed

    Plugge, C M; Stams, A J M

    2002-04-01

    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 inoculum originated from anaerobic methanogenic granular sludge bed reactors. The microbial population was monitored over a period of 2 years using the most probable number (MPN) technique. In the reactor glutamate was readily degraded to ammonium, methane, and carbon dioxide. Cell numbers of glutamate-degrading organisms increased 400-fold over the first year. In medium supplemented with bromoethane sulfonic acid (BES, an inhibitor of methanogenesis), tenfold lower cell numbers were counted, indicating the syntrophic nature of glutamate degradation. After 2 years of reactor operation the predominant organisms were isolated and characterized. Methanobacterium thermoautotrophicum (strain R43) and a Methanosaeta thermophila strain (strain A) were the predominant hydrogenotrophic and acetoclastic methanogens, respectively. The numbers in which the organisms were present in the reactor after 24 months of incubation were 8.6 x 10(9) and 3.8 x 10(7) mL(-1) sludge, respectively. The most predominant glutamate-degrading organism (8.6 x 10(7) mL(-1) sludge), strain Z, was identified as a new species, Caloramator coolhaasii. It converted glutamate to hydrogen, acetate, some propionate, ammonium, and carbon dioxide. Growth of this syntrophic organism on glutamate was strongly enhanced by the presence of methanogens.

  2. Two-phase (acidogenic-methanogenic) anaerobic thermophilic/mesophilic digestion system for producing Class A biosolids from municipal sludge.

    PubMed

    Rubio-Loza, L A; Noyola, A

    2010-01-01

    Two different arrangements of two-phase anaerobic sludge systems were operated treating a mixture of primary and secondary sludge. Two steady state periods were evaluated: the first acidogenic thermophilic phase was operated at hydraulic retention times of 3 and 2 days and the second methanogenic (mesophilic and thermophilic) phases at 13 and 10 days. The two-phase systems had an efficient removal of pathogens and parasites, achieving values lower than those specified for Class A biosolids, according to the Mexican Standard NOM-004-SEMARNAT-2002. The first thermophilic phase achieved almost complete destruction of pathogens and parasites by itself. During the second steady state period, volatile fatty acids accumulated in the second methanogenic phases (HRT of 10 days and an organic load of 3 kg VS/m(3)d) indicating that the systems were overloaded, mainly the mesophilic digester. In this case, the accumulation of propionic acid may be related to a deficiency of micronutrients. The results show that the two-phase thermophilic/mesophilic anaerobic sludge digestion may be considered as an adequate option for the production of Class A biosolids.

  3. Mesophilic and thermophilic anaerobic biodegradability of water hyacinth pre-treated at 80 {sup o}C

    SciTech Connect

    Ferrer, Ivet; Campos, Elena; Flotats, Xavier

    2010-10-15

    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 {sup o}C was also evaluated. To this end, anaerobic biodegradability tests were carried out at 35 {sup o}C and 55 {sup 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{sub 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{sub 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.

  4. The effect of shock loading on the performance of a thermophilic anaerobic contact reactor at constant organic loading rate

    PubMed Central

    2014-01-01

    The influences of organic loading disturbances on the process performance of a thermophilic anaerobic contact reactor treating potato-processing wastewater were investigated. For this purpose, while the reactor was operated at steady state conditions with organic loading rate of 5.5 kg COD/m3 · day, an instant acetate concentration increase (1 g/L) was introduced to the reactor. During the shock loading test of acetate, it was observed that the overall process performance was adversely affected by all the shock loading, however, the system reached steady state conditions less than 24 hours of operation indicating that thermophilic anaerobic contact reactor is resistant to shock loading and be capable of returning its normal conditions within a short time period. PMID:24872886

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

    PubMed

    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 CH4/gVSadded/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.

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

    PubMed

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

    2014-06-01

    The removal of endocrine disrupting compounds (EDCs) and non-steroidal anti-inflammatory drugs (NSAIDs) was studied in three lab-scale anaerobic digestion (AD) systems; a single-stage mesophilic, a single-stage thermophilic and a two-stage thermophilic/mesophilic. All micropollutants underwent microbial degradation. High removal efficiency (>80%) was calculated for diclofenac, ibuprofen, naproxen and ketoprofen; whereas triclosan, bisphenol A and the sum of nonylphenol (NP), nonylphenol monoethoxylate (NP1EO) and nonylphenol diethoxylate were moderately removed (40-80%). NSAIDs removal was not affected by the type of AD system used; whereas slightly higher EDCs removal was observed in two-stage system. In this system, most microcontaminants were removed in thermophilic digester. Biotransformation of NP1EO and NP was affected by the temperature applied to bioreactors. Under mesophilic conditions, higher removal of NP1EO and accumulation of NP was noticed; whereas the opposite was observed under thermophilic conditions. For most analytes, higher specific removal rates were calculated under thermophilic conditions and 20 days SRT. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Two-stage thermophilic-mesophilic anaerobic digestion of waste activated sludge from a biological nutrient removal plant.

    PubMed

    Watts, S; Hamilton, G; Keller, J

    2006-01-01

    A two-stage thermophilic-mesophilic anaerobic digestion pilot-plant was operated solely on waste activated sludge (WAS) from a biological nutrient removal (BNR) plant. The first-stage thermophilic reactor (HRT 2 days) was operated at 47, 54 and 60 degrees C. The second-stage mesophilic digester (HRT 15 days) was held at a constant temperature of 36-37 degrees C. For comparison with a single-stage mesophilic process, the mesophilic digester was also operated separately with an HRT of 17 days and temperature of 36-37 degrees C. The results showed a truly thermophilic stage (60 degrees C) was essential to achieve good WAS degradation. The lower thermophilic temperatures examined did not offer advantages over single-stage mesophilic treatment in terms of COD and VS removal. At a thermophilic temperature of 60 degrees C, the plant achieved 35% VS reduction, representing a 46% increase compared to the single-stage mesophilic digester. This is a significant level of degradation which could make such a process viable in situations where there is no primary sludge generated. The fate of the biologically stored phosphorus in this BNR sludge was also investigated. Over 80% of the incoming phosphorus remained bound up with the solids and was not released into solution during the WAS digestion. Therefore only a small fraction of phosphorus would be recycled to the main treatment plant with the dewatering stream.

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

    PubMed

    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.

  9. Thermobrachium celere gen. nov., sp. nov., a rapidly growing thermophilic, alkalitolerant, and proteolytic obligate anaerobe

    SciTech Connect

    Engle, M.; Youhong Li; DeBlois, S.

    1996-10-01

    More than 40 isolates of a novel, ubiquitous, proteolytic, moderately alkaliphilic, thermophilic obligate anaerobe were obtained from geothermally and anthropogenically heated environments and mesobiotic environments located on three continents. Whole-cell protein sodium dodecyl sulfate gel electrophoresis revealed that most of these organisms are very similar. Eight of the isolates were characterized in detail; this analysis included 16S ribosomal DNA sequence analysis. The cells of those organisms are (depending on the isolate) 0.5 to 0.8 {mu}m long, exhibit tumbling motility, and have a positive Gram stain reaction. The temperature range for growth is 43{degrees} to 75{degrees}C (optimum temperature, 66{degrees}C), and the pH range for growth is 5.4 to 9.5 (optimum pH, 8.2); the shortest doubling time is around 10 min. Yeast extract is required for growth, and (depending on the strain) glucose, sucrose, fructose, galactose, and ribose are utilized. The fermentation products from glucose in the presence of yeast extract are CO{sub 2}, H{sub 2}, formate, and ethanol. The G+C content is 30 to 31 mol%. On the basis of these properties, which differentiate these strains from all alkalitolerant thermophiles described previously, and the results of a comparison of the 16S ribosomal DNA sequences of these organisms with previously described sequences, we propose that our isolates be placed in a single species of the new genus Thermobrachium; strain JW/YL-NZ35 is the type strain of the type species, Thermobrachium celere.

  10. Effect of moisture of municipal biowaste on start-up and efficiency of mesophilic and thermophilic dry anaerobic digestion.

    PubMed

    Li, Chaoran; Mörtelmaier, Christoph; Winter, Josef; Gallert, Claudia

    2014-09-01

    Methane production from biowaste with 20-30% dry matter (DM) by box-type dry anaerobic digestion and contributing bacteria were determined for incubation at 20, 37 and 55 °C. The same digestion efficiency as for wet anaerobic digestion of biowaste was obtained for dry anaerobic digestion with 20% DM content at 20, 37 and 55 °C and with 25% DM content at 37 and 55 °C. No or only little methane was produced in dry anaerobic reactors with 30% DM at 20, 37 or 55 °C. Population densities in the 20-30% DM-containing biowaste reactors were similar although in mesophilic and thermophilic biowaste reactors with 30% DM content significantly less but phylogenetically more diverse archaea existed. Biogas production in the 20% and 25% DM assays was catalyzed by Methanosarcinales and Methanomicrobiales. In all assays Pelotomaculum and Syntrophobacter species were dominant propionate degraders. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

    PubMed

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

    2014-02-01

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

  12. From mesophilic to thermophilic digestion: the transitions of anaerobic bacterial, archaeal, and fungal community structures in sludge and manure samples.

    PubMed

    Sun, Weimin; Yu, Guangwei; Louie, Tiffany; Liu, Tong; Zhu, Chengsheng; Xue, Gang; Gao, Pin

    2015-12-01

    The shift of microbial communities during a transition from mesophilic anaerobic digestion (MAD) to thermophilic anaerobic digestion (TAD) was characterized in two treatments. One treatment was inoculated with sludge and the other was inoculated with manure. In this study, methane was produced both in MAD and TAD, but TAD has slightly more methane produced than MAD. A broad phylogenetic spectrum of bacterial, archaeal, and fungal taxa at thermophilic conditions was detected. Coprothermobacter, Bacillus, Haloplasma, Clostridiisalibacter, Methanobacterium, Methanothermobacter, Saccharomycetales, Candida, Alternaria, Cladosporium, and Penicillium were found almost exclusively in TAD, suggesting their adaptation to thermophilic conditions and ecological roles in digesting the organic compounds. The characterization of the lesser-known fungal community revealed that fungi probably constituted an important portion of the overall community within TAD and contributed to this process by degrading complex organic compounds. The shift of the microbial communities between MAD and TAD implied that temperature drastically affected the microbial diversity in anaerobic digestion. In addition, the difference in microbial communities between sludge and manure indicated that different source of inoculum also affected the microbial diversity and community.

  13. [Conversion of acetic acid to methane by thermophiles]. Annual progress report

    SciTech Connect

    Zinder, S.H.

    1994-02-01

    Acetate is the precursor of approximately two-thirds of the methane produced by anaerobic bioreactors and many other methanogenic habitats. Besides their intrinsic interest, thermophilic acetotrophic methanogenic cultures usually grow at least twice as fast as their mesophilic counterparts, making them more amenable to study. In recent years, attention has been mainly focused on the thermophilic acetate utilizing methanogen Methanothrix strain CALS-1. Methanothrix, also called Methanosaeta, is one of only two methanogenic genera known to convert acetate to methane, the other being Methanosarcina. The faster-growing more versatile Methanosarcina has been better studied. However, when one examines anaerobic digestor contents, Methanothrix is often the dominant acetate-utilizing methanogen. As described in previous progress reports, the authors have achieved methanogenesis from acetate in cell-free extracts of Methanothrix strain CALS-1 grown in a pH auxostat. Using these cell extracts, specific activities for methanogenesis from acetate and ATP of 100--300 nmol/min were routinely obtained, levels comparable to the rate in whole cells, which is not usually the case in methanogenic extracts. Recently obtained results are given and discussed for the following: Methanogenesis in crude extracts; Role of the cell membrane in methanogenesis from acetate; Carbon monoxide dehydrogenase; Novel thermophilic cultures converting acetate to methane; and Methanol-utilizing methanogen.

  14. Removal of fecal indicator organisms and parasites (fecal coliforms and helminth eggs) from municipal biologic sludge by anaerobic mesophilic and thermophilic digestion.

    PubMed

    Rojas Oropeza, M; Cabirol, N; Ortega, S; Castro Ortiz, L P; Noyola, A

    2001-01-01

    In this work, two egg-shaped, 5L-volume, anaerobic sludge digesters were used, one under mesophilic conditions (35 degrees C, M1), and the other under thermophilic conditions (55 degrees C, T1). Both digesters were fed with the purged sludge from an anaerobic treatment plant (start-up period) and from an activated sludge plant (stabilization period), treating municipal wastewaters. The purpose of the study was to establish the technical feasibility of the anaerobic thermophilic sludge treatment comparatively, during the stages of start-up and stabilization of the process, for removing pathogenic microorganisms and parasites efficiently. The results show that, in both stages, the anaerobic thermophilic digester presents higher efficiency on the removal of pathogens and parasites, than the mesophilic digester. Anaerobic thermophilic digestion is close to complying with the EPA (1998) limits for "Class A" type biosolids, referring to the number of parasitic helminth eggs (0.25 HELarval/gTS), and to the pathogen indicator fecal coliforms (< 1000 MPN/gTS). Therefore, the results show that thermophilic anaerobic digestion of biologic sludge may be considered as a suitable technology for the production of Class A biosolids, for further use in agriculture without restrictions.

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

    PubMed

    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.

  16. Performance of anaerobic thermophilic fluidized bed in the treatment of cutting-oil wastewater.

    PubMed

    Perez, M; Rodriguez-Cano, R; Romero, L I; Sales, D

    2007-12-01

    This paper examines the effect of organic loading rate on the removal efficiency of COD and TOC anaerobic thermophilic fluidized bed reactor (AFBR) in the treatment of cutting-oil wastewater at different hydraulic retention time (HRT) conditions. The essays are development at laboratory scale using a porous support medium. The AFBR reactor was subjected to a programme of steady-state operation over a range of hydraulic retention times, HRTs, in the range 12-2h and organic loading rates, OLRs, between 11.9 and 51.3kgCOD/m(3)d. The highest efficiency was 95.9% for an OLR of 13kgCOD/m(3)d and HRT of 11h. Over an operating period of 92 days, an OLR of 51.3kgCOD/m(3)d was achieved with 67.1% COD removal efficiency (71.3% TOC) in the experimental AFBR reactor. Although the level of biogas generation was not high, the anaerobic fluidized bed technology provided significant advantages over the conventional physico-chemical treatment applied in the factory. The effluent had a better quality (lower organic loading) and it was possible to reuse it in different applications in the factory (e.g., irrigation of gardens). The biological treatment did not lead to the generation of oily sludge, which is considered as hazardous waste by legislation. Furthermore, a continuous stream is produced and this reduced the impact of large flows discharged 4-5 times per week to the urban collector and MWWTP (municipal wastewater treatment plant).

  17. Anaerobic co-digestion of food waste and chemically enhanced primary-treated sludge under mesophilic and thermophilic conditions.

    PubMed

    Obulisamy, Parthiba Karthikeyan; Chakraborty, Debkumar; Selvam, Ammaiyappan; Wong, Jonathan W C

    2016-12-01

    Anaerobic co-digestion of food waste with primary sewage sludge is beneficial for urban centers, while the optimized conditions reported in the literature are not locally suitable for Hong Kong. Therefore, the present study was aimed to develop an optimized mixing ratio of food waste to chemically enhanced primary-treated sewer sludge (CEPT) for co-digestion using batch tests under mesophilic (37°C) and thermophilic (55°C) conditions. The mixing ratios of 1:1, 1:2, 1:3, 2:1 and 3:1 (v v(-1)) of food waste to CEPT sludge was tested under the following conditions: temperature - 35°C and 55°C; pH - not regulated; agitation - 150 rpm and time - 20 days. The thermophilic incubations led a good hydrolysis rate and 2-12-fold higher enzyme activities than in mesophilic incubations for different mixing ratios. While the acidogenesis were found retarded that leading to 'sour and stuck' digestion for all mixing ratio of food waste to CEPT sludge from thermophilic incubations. The measured zeta potential was most favourable (-5 to -16.8 mV) for methane production under thermophilic incubations; however the CH4 recovery was less than that in mesophilic incubations. The results suggested that the quick hydrolysis and subsequent acid accumulation under thermophilic incubation lead to inhibited methanogenesis at the early stage than in mesophilic systems. It is concluded that buffer addition is therefore required for any mixing ratio of food waste to CEPT sludge for improved CH4 recovery for both mesophilic and thermophilic operations.

  18. Retooling the ethanol industry: thermophilic anaerobic digestion of thin stillage for methane production and pollution prevention.

    PubMed

    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.

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

    PubMed

    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.

  20. Molecular analysis of meso- and thermophilic microbiota associated with anaerobic biowaste degradation

    PubMed Central

    2012-01-01

    Background Microbial anaerobic digestion (AD) is used as a waste treatment process to degrade complex organic compounds into methane. The archaeal and bacterial taxa involved in AD are well known, whereas composition of the fungal community in the process has been less studied. The present study aimed to reveal the composition of archaeal, bacterial and fungal communities in response to increasing organic loading in mesophilic and thermophilic AD processes by applying 454 amplicon sequencing technology. Furthermore, a DNA microarray method was evaluated in order to develop a tool for monitoring the microbiological status of AD. Results The 454 sequencing showed that the diversity and number of bacterial taxa decreased with increasing organic load, while archaeal i.e. methanogenic taxa remained more constant. The number and diversity of fungal taxa increased during the process and varied less in composition with process temperature than bacterial and archaeal taxa, even though the fungal diversity increased with temperature as well. Evaluation of the microarray using AD sample DNA showed correlation of signal intensities with sequence read numbers of corresponding target groups. The sensitivity of the test was found to be about 1%. Conclusions The fungal community survives in anoxic conditions and grows with increasing organic loading, suggesting that Fungi may contribute to the digestion by metabolising organic nutrients for bacterial and methanogenic groups. The microarray proof of principle tests suggest that the method has the potential for semiquantitative detection of target microbial groups given that comprehensive sequence data is available for probe design. PMID:22727142

  1. Glycerol acts as alternative electron sink during syngas fermentation by thermophilic anaerobe Moorella thermoacetica.

    PubMed

    Kimura, Zen-ichiro; Kita, Akihisa; Iwasaki, Yuki; Nakashimada, Yutaka; Hoshino, Tamotsu; Murakami, Katsuji

    2016-03-01

    Moorella thermoacetica is an anaerobic thermophilic acetogen that is capable of fermenting sugars, H(2)/CO(2) and syngas (H(2)/CO). For this reason, this bacterium is potentially useful for biotechnology applications, particularly the production of biofuel from CO(2). A soil isolate of M. thermoacetica, strain Y72, produces both ethanol and acetate from H(2)/CO(2); however, the maximum concentrations of these two products are too low to enable commercialization of the syngas fermentation process. In the present study, glycerol was identified as a novel electron sink among the fermentation products of strain Y72. Notably, a 1.5-fold increase in the production of ethanol (1.4 mM) was observed in cultures supplemented with glycerol during syngas fermentation. This discovery is expected to aid in the development of novel methods that allow for the regulation of metabolic pathways to direct and increase the production of desirable fermentative compounds. Copyright © 2015. Published by Elsevier B.V.

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

    PubMed

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

    2016-10-01

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

  3. Molecular analysis of meso- and thermophilic microbiota associated with anaerobic biowaste degradation.

    PubMed

    Ritari, Jarmo; Koskinen, Kaisa; Hultman, Jenni; Kurola, Jukka M; Kymäläinen, Maritta; Romantschuk, Martin; Paulin, Lars; Auvinen, Petri

    2012-06-22

    Microbial anaerobic digestion (AD) is used as a waste treatment process to degrade complex organic compounds into methane. The archaeal and bacterial taxa involved in AD are well known, whereas composition of the fungal community in the process has been less studied. The present study aimed to reveal the composition of archaeal, bacterial and fungal communities in response to increasing organic loading in mesophilic and thermophilic AD processes by applying 454 amplicon sequencing technology. Furthermore, a DNA microarray method was evaluated in order to develop a tool for monitoring the microbiological status of AD. The 454 sequencing showed that the diversity and number of bacterial taxa decreased with increasing organic load, while archaeal i.e. methanogenic taxa remained more constant. The number and diversity of fungal taxa increased during the process and varied less in composition with process temperature than bacterial and archaeal taxa, even though the fungal diversity increased with temperature as well. Evaluation of the microarray using AD sample DNA showed correlation of signal intensities with sequence read numbers of corresponding target groups. The sensitivity of the test was found to be about 1%. The fungal community survives in anoxic conditions and grows with increasing organic loading, suggesting that Fungi may contribute to the digestion by metabolising organic nutrients for bacterial and methanogenic groups. The microarray proof of principle tests suggest that the method has the potential for semiquantitative detection of target microbial groups given that comprehensive sequence data is available for probe design.

  4. Thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste.

    PubMed

    Forster-Carneiro, T; Pérez, M; Romero, L I

    2008-10-01

    The influence of different organic fraction of municipal solid wastes during anaerobic thermophilic (55 degrees C) treatment of organic matter was studied in this work: food waste (FW), organic fraction of municipal solid waste (OFMSW) and shredded OFMSW (SH_OFMSW). All digester operated at dry conditions (20% total solids content) and were inoculated with 30% (in volume) of mesophilic digested sludge. Experimental results showed important different behaviours patterns in these wastes related with the organic matter biodegradation and biogas and methane production. The FW reactor showed the smallest waste biodegradation (32.4% VS removal) with high methane production (0.18 LCH4/gVS); in contrast the SH_OFMSW showed higher waste biodegradation (73.7% VS removal) with small methane production (0.05 LCH4/g VS). Finally, OFMSW showed the highest VS removal (79.5%) and the methane yield reached 0.08 LCH4/g VS. Therefore, the nature of organic substrate has an important influence on the biodegradation process and methane yield. Pre-treatment of waste is not necessary for OFMSW.

  5. Simultaneous hydrolysis and fermentation of unprocessed food waste into ethanol using thermophilic anaerobic bacteria.

    PubMed

    Dhiman, Saurabh Sudha; David, Aditi; Shrestha, Namita; Johnson, Glenn R; Benjamin, Kenneth M; Gadhamshetty, Venkataramana; Sani, Rajesh K

    2017-11-01

    The one-pot CRUDE (Conversion of Raw and Untreated Disposal into Ethanol) process was developed for simultaneous hydrolysis and fermentation of unprocessed food waste into ethanol using thermophilic (growing at 65°C) anaerobic bacteria. Unlike existing waste to energy technologies, the CRUDE process obviates the need for any pre-treatment or enzyme addition. A High-Temperature-High-Pressure (HTHP) distillation technique was also applied that facilitated efficient use of fermentation medium, inoculum recycling, and in-situ ethanol collection. For material balancing of the process, each characterized component was represented in terms of C-mol. Recovery of 94% carbon at the end confirmed the operational efficiency of CRUDE process. The overall energy retaining efficiency calculated from sugars to ethanol was 1262.7kJdryweightkg(-1) of volatile solids using HTHP. These results suggest that the CRUDE process can be a starting point for the development of a commercial ethanol production process. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    PubMed

    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.

  7. Dry-thermophilic anaerobic digestion of simulated organic fraction of municipal solid waste: process modeling.

    PubMed

    Fdez-Güelfo, L A; Álvarez-Gallego, C; Sales Márquez, D; Romero García, L I

    2011-01-01

    Solid retention time (SRT) is a very important operational variable in continuous and semicontinuous waste treatment processes since the organic matter removal efficiency--expressed in terms of percentage of Dissolved Organic Carbon (% DOC) or Volatile Solids (% VS) removed--and the biogas or methane production are closely related with the SRT imposed. Optimum SRT is depending on the waste characteristics and the microorganisms involved in the process and, hence, it should be determined specifically in each case. In this work a series of experiments were carried out to determine the effect of SRT, from 40 to 8 days, on the performance of the dry (30% Total Solids) thermophilic (55°C) anaerobic digestion of organic fraction of Municipal Solid Wastes (OFMSW) operating at semicontinuous regime of feeding. The experimental results show than 15days is the optimum SRT (the best between all proved) for this process. Besides, data of organic matter concentration and methane production versus SRT have been used to obtain the kinetic parameters of the kinetic model of Romero García (1991): the maximum specific growth rate of the microorganisms (μmax=0.580 days(-1)) and the fraction of substrate non-biodegradable (α=0.268).

  8. Reductive dechlorination of tetrachloroethene to cis-1, 2-dichloroethene by a thermophilic anaerobic enrichment culture.

    PubMed

    Kengen, S W; Breidenbach, C G; Felske, A; Stams, A J; Schraa, G; de Vos, W M

    1999-06-01

    Thermophilic anaerobic biodegradation of tetrachloroethene (PCE) was investigated with various inocula from geothermal and nongeothermal areas. Only polluted harbor sediment resulted in a stable enrichment culture that converted PCE via trichloroethene to cis-1, 2-dichloroethene at the optimum temperature of 60 to 65 degrees C. After several transfers, methanogens were eliminated from the culture. Dechlorination was supported by lactate, pyruvate, fructose, fumarate, and malate as electron donor but not by H2, formate, or acetate. Fumarate and L-malate led to the highest dechlorination rate. In the absence of PCE, fumarate was fermented to acetate, H2, CO2, and succinate. With PCE, less H2 was formed, suggesting that PCE competed for the reducing equivalents leading to H2. PCE dechlorination, apparently, was not outcompeted by fumarate as electron acceptor. At the optimum dissolved PCE concentration of approximately 60 microM, a high dechlorination rate of 1.1 micromol h-1 mg-1 (dry weight) was found, which indicates that the dechlorination is not a cometabolic activity. Microscopic analysis of the fumarate-grown culture showed the dominance of a long thin rod. Molecular analysis, however, indicated the presence of two dominant species, both belonging to the low-G+C gram positives. The highest similarity was found with the genus Dehalobacter (90%), represented by the halorespiring organism Dehalobacter restrictus, and with the genus Desulfotomaculum (86%).

  9. Reductive Dechlorination of Tetrachloroethene to cis-1,2-Dichloroethene by a Thermophilic Anaerobic Enrichment Culture

    PubMed Central

    Kengen, Servé W. M.; Breidenbach, Caroline G.; Felske, Andreas; Stams, Alfons J. M.; Schraa, Gosse; de Vos, Willem M.

    1999-01-01

    Thermophilic anaerobic biodegradation of tetrachloroethene (PCE) was investigated with various inocula from geothermal and nongeothermal areas. Only polluted harbor sediment resulted in a stable enrichment culture that converted PCE via trichloroethene to cis-1,2-dichloroethene at the optimum temperature of 60 to 65°C. After several transfers, methanogens were eliminated from the culture. Dechlorination was supported by lactate, pyruvate, fructose, fumarate, and malate as electron donor but not by H2, formate, or acetate. Fumarate and l-malate led to the highest dechlorination rate. In the absence of PCE, fumarate was fermented to acetate, H2, CO2, and succinate. With PCE, less H2 was formed, suggesting that PCE competed for the reducing equivalents leading to H2. PCE dechlorination, apparently, was not outcompeted by fumarate as electron acceptor. At the optimum dissolved PCE concentration of ∼60 μM, a high dechlorination rate of 1.1 μmol h−1 mg−1 (dry weight) was found, which indicates that the dechlorination is not a cometabolic activity. Microscopic analysis of the fumarate-grown culture showed the dominance of a long thin rod. Molecular analysis, however, indicated the presence of two dominant species, both belonging to the low-G+C gram positives. The highest similarity was found with the genus Dehalobacter (90%), represented by the halorespiring organism Dehalobacter restrictus, and with the genus Desulfotomaculum (86%). PMID:10347007

  10. Isolation and characterization of a moderately thermophilic anaerobic alkaliphile, Clostridium paradoxum sp. nov.

    SciTech Connect

    Youhong Li; Wiegel, J.; Mandelco, L.

    1993-07-01

    Alkaliphilic, moderately thermophilic anaerobic bacteria able to grow above pH 10.5 and 55{degrees}C were isolated from various sewage plants in the United States. The strains were motile with two to six peritrichous flagella and formed round to slightly oval terminal spores in terminally distended and slightly enlarged cells. Sporulated cells remained motile. The pH range for growth was between 7.0 and 11.1, with an optimum of around 10.1. At pH 10.1 the temperature range for growth was between 30 and 63{degrees}C, with an optimum of 56{degrees}C. The shortest observed doubling time (glucose) was around 16 min at 56{degrees}C and pH 10.1. No dissimilatory sulfate reduction was detected. The organism utilized glucose, fructose, sucrose, maltose, and pyruvate but required yeast extract or tryptone for growth. Optimal NaCl concentrations for growth were between 50 and 200 mM. The guanine-plus-cytosine content was 30.0 {+-} 0.10 mol%. On the basis of unique properties and 16S rRNA analysis, the strains are placed in a new species, Clostridium paradoxum, referring to the unusual retainment of motility by sporulated cells. Strain JW-YL-7 (DSM 7308) is designated as the type strain.

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

    PubMed Central

    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. PMID:26609436

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

    PubMed

    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.

  13. Survival of multidrug-resistant bacteria in thermophilic and mesophilic anaerobic co-digestion of dairy manure and waste milk.

    PubMed

    Beneragama, Nilmini; Iwasaki, Masahiro; Lateef, Suraju A; Yamashiro, Takaki; Ihara, Ikko; Umetsu, Kazutaka

    2013-05-01

    Anaerobic digestion is considered as a promising method to manage animal waste with antibiotic-resistant bacteria. Current research was conducted to investigate the survival of multidrug-resistant bacteria (MDRB) resistant to three groups of antibiotics: (i) cefazolin, neomycin, vancomycin, kanamycin (group 1); (ii) penicillin, oxytetracycline, ampicillin, streptomycin (group 2); and (iii) cefazolin, neomycin, vancomycin, kanamycin, penicillin, oxytetracycline, ampicillin, streptomycin (group 3), in anaerobic digestion of dairy manure and co-digestion of dairy manure and waste milk at 37°C and 55°C for 22 days, respectively. The population densities of three groups of MDRB on peptone, tryptone, yeast and glucose agar plates incubated at 30°C for 7 days before and after digestion showed 100% destruction in both digestates at thermophilic temperature. Overall reduction of more than 90% of three groups of MDRB was observed in mesophilic digestion with no significant differences (P > 0.05) between manure and milk mixture. Co-digestion of dairy manure and waste milk always produced significantly (P < 0.05) higher total gas and methane gas than digestion of manure alone at both temperatures. Gas production in each case was significantly (P < 0.05) higher in thermophilic digestion than in mesophilic digestion. The results demonstrate that thermophilic co-digestion of dairy manure and waste milk offers more benefits in terms of the environment and economy.

  14. Dry-thermophilic anaerobic digestion of organic fraction of the municipal solid waste: focusing on the inoculum sources.

    PubMed

    Forster-Carneiro, T; Pérez, M; Romero, L I; Sales, D

    2007-12-01

    The effect of inoculum source on anaerobic thermophilic digestion of separately collected organic fraction of municipal solid wastes (SC_OFMSW) has been studied. Performance of laboratory scale reactors (V: 1.1 L) were evaluated using six different inoculums sources: (1) corn silage (CS); (2) restaurant waste digested mixed with rice hulls (RH_OFMSW); (3) cattle excrement (CATTLE); (4) swine excrement (SWINE); (5) digested sludge (SLUDGE); and (6) SWINE mixed with SLUDGE (1:1) (SWINE/SLUDGE). The SC_OFMSW was separately and collected from university restaurant. The selected conditions were: 25% of inoculum, 30% of total solid and 55 degrees C of temperature, optimum in the thermophilic range. The six inoculum sources showed an initial start-up phase in the range between 2 and 4 days and the initial methane generation began over 10 days operational process. Results indicated that SLUDGE is the best inoculum source for anaerobic thermophilic digestion of the treatment of organic fraction of municipal solid waste at dry conditions (30%TS). Over 60 days operating period, it was confirmed that SLUDGE reactor can achieve 44.0%COD removal efficiency and 43.0%VS removal. In stabilization phase, SLUDGE reactor showed higher volumetric biogas generated of 78.9 mL/day (or 35.6 mLCH(4)/day) reaching a methane yield of 0.53 LCH(4)/gVS. Also, SWINE/SLUDGE and SWINE were good inoculums at these experimental conditions.

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

    PubMed

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

    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.

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

    SciTech Connect

    Bolzonella, David; Cavinato, Cristina; Fatone, Francesco; Pavan, Paolo; Cecchi, Franco

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer High temperatures were tested in single and two-stage anaerobic digestion of waste activated sludge. Black-Right-Pointing-Pointer The increased temperature demonstrated the possibility of improving typical yields of the conventional mesophilic process. Black-Right-Pointing-Pointer The temperature phased anaerobic digestion process (65 + 55 Degree-Sign C) showed the best performances with yields of 0.49 m{sup 3}/kgVS{sub fed}. Black-Right-Pointing-Pointer Ammonia and phosphate released from solids destruction determined the precipitation of struvite in the reactor. - Abstract: The paper reports the findings of a two-year pilot scale experimental trial for the mesophilic (35 Degree-Sign C), thermophilic (55 Degree-Sign C) and temperature phased (65 + 55 Degree-Sign C) anaerobic digestion of waste activated sludge. During the mesophilic and thermophilic runs, the reactor operated at an organic loading rate of 2.2 kgVS/m{sup 3}d and a hydraulic retention time of 20 days. In the temperature phased run, the first reactor operated at an organic loading rate of 15 kgVS/m{sup 3}d and a hydraulic retention time of 2 days while the second reactor operated at an organic loading rate of 2.2 kgVS/m{sup 3}d and a hydraulic retention time of 18 days (20 days for the whole temperature phased system). The performance of the reactor improved with increases in temperature. The COD removal increased from 35% in mesophilic conditions, to 45% in thermophilic conditions, and 55% in the two stage temperature phased system. As a consequence, the specific biogas production increased from 0.33 to 0.45 and to 0.49 m{sup 3}/kgVS{sub fed} at 35, 55, and 65 + 55 Degree-Sign C, respectively. The extreme thermophilic reactor working at 65 Degree-Sign C showed a high hydrolytic capability and a specific yield of 0.33 gCOD (soluble) per gVS{sub fed}. The effluent of the extreme thermophilic reactor showed an average concentration of soluble COD and volatile

  17. Thermovenabulum ferriorganovorum gen. nov., sp. nov., a novel thermophilic, anaerobic, endospore-forming bacterium.

    PubMed

    Zavarzina, D G; Tourova, T P; Kuznetsov, B B; Bonch-Osmolovskaya, E A; Slobodkin, A I

    2002-09-01

    A thermophilic, anaerobic, spore-forming bacterium (strain Z-9801T) was isolated from a terrestrial hydrothermal source in the Uzon caldera on the Kamchatka peninsula. Cells of strain Z-9801T were straight, sometimes branched rods, 0.5-0.6 microm in diameter and 1.5-7.0 microm in length, with peritrichous flagella. The temperature range for growth was 45-76 degrees C, with an optimum at 63-65 degrees C. The pH range for growth was 4.8-8.2, with an optimum at 6.7-6.9. The substrates utilized by strain Z-9801T included peptone, yeast extract, beef extract, Casamino acids, starch, pyruvate, melibiose, sucrose, fructose, maltose, xylose and ribose. The fermentation products from melibiose were ethanol, acetate, H2 and CO2. Strain Z-9801T used H2 in the presence of Fe(III) and an organic electron donor. Strain Z-9801T reduced Fe(III), Mn(IV), nitrate, fumarate, sulfite, thiosulfate, elemental sulfur and 9,10-anthraquinone 2,6-disulfonate. The G+C content of strain Z-9801T DNA was 36 mol%. 16S rDNA sequence analysis revealed that the isolated organism forms a separate branch within the Bacillus/Clostridium group. On the basis of physiological properties and phylogenetic analysis, it is proposed that strain Z-9801T (= DSM 14006T = UNIQEM 210T) should be assigned to a novel species of a new genus, Thermovenabulum ferriorganovorum gen. nov., sp. nov.

  18. Fermentation of particulate organic matter to methane in a thermophilic anaerobic attached film expanded bed reactor

    SciTech Connect

    Clarkson, W.W.

    1986-01-01

    The anaerobic attached film expanded bed (AAFEB) has been applied to dilute sewage at low temperatures and to soluble organics at thermophilic temperatures. In this study, microcrystalline cellulose was used to determine the sites and rates of particle conversion to methane in bench-scale AAFEB reactors at 55/sup 0/C. The reactors had expanded bed volumes of 500 ml composed of inert diatomaceous earth grains approximately 0.4 mm in diameter supporting thin films. Methanogenic biofilms could be established on soluble feed within 30 days. Over a 27-month experimental period, cellulose was fed to the expanded beds at volumetric loads from 2 to 69 g COD/lxd. Total COD conversion efficiencies were 90 to 20% and cellulose solubilization efficiencies were 92 to 53% in the methane forming reactors. Hydrolysis was mediated by suspended bacteria colonizing the cellulose particles. High slug cellulose loads to the AAFEB indicated a maximum potential hydrolysis rate in excess of 75 g COD/lxd, which exceeds the maximum reported methanogenesis rate. Suspended-growth reactors were used to determine kinetic parameters of the hydrolytic bacteria at 55/sup 0/C. Specific cellulose conversion rate was 4.8 g COD/g cellsxd, equivalent to values calculated from the AAFEB data. Yield of hydrolyzers = 0.22 g VS/g CODxd, and decay coefficients = 0.05 d/sup -1/. A small amount of methane was produced at SRT as low as 1.5 days at pH 6. Biofilm reactors were found to be stable and capable of efficient conversion of high loadings of organic suspended solids. Biofilm and suspended bacteria play unique roles in the process.

  19. Biogas Production from Distilled Grain Waste by Thermophilic Dry Anaerobic Digestion: Pretreatment of Feedstock and Dynamics of Microbial Community.

    PubMed

    Wang, Ting-Ting; Sun, Zhao-Yong; Huang, Yu-Lian; Tan, Li; Tang, Yue-Qin; Kida, Kenji

    2017-08-24

    Distilled grain waste (DGW) eluted from the Chinese liquor making process poses potential serious environmental problems. The objective of this study is to evaluate the feasibility of converting DGW to biogas by thermophilic dry anaerobic digestion. To improve biogas production, the effects of dilute H2SO4 and thermal pretreatment on DGW were evaluated by biochemical methane potential (BMP) tests. The results indicate that 90 °C thermal pretreatment provided the highest methane production at 212.7 mL/g-VTSadd. The long-term thermophilic dry anaerobic digestion process was conducted in a 5-L separable flask for more than 3 years at a volatile total solid (VTS) loading rate of 1 g/kg-sludge/d, using synthetic waste, untreated and 90 °C thermal pretreated DGW as the feedstock, respectively. A higher methane production, 451.6 mL/g-VTSadd, was obtained when synthetic waste was used; the methane production decreased to 139.4 mL/g-VTSadd when the untreated DGW was used. The 90 °C thermal pretreated DGW increased the methane production to 190.5 mL/g-VTSadd, showing an increase of 36.7% in methane production compared with that using untreated DGW. The microbial community structure analysis indicates that the microbial community in the thermophilic dry anaerobic digestion system maintained a similar structure when untreated or pretreated DGW was used, whereas the structure differed significantly when synthetic waste was used as the feedstock.

  20. Effect of temperature on ethanol tolerance of a thermophilic anaerobic ethanol producer Thermoanaerobacter A10: modeling and simulation.

    PubMed

    Georgieva, Tania I; Skiadas, Ioannis V; Ahring, Birgitte K

    2007-12-15

    The low ethanol tolerance of thermophilic anaerobic bacteria (<2%, v/v) is a major obstacle for their industrial exploitation for ethanol production. The ethanol tolerance of the thermophilic anaerobic ethanol-producing strain Thermoanaerobacter A10 was studied during batch tests of xylose fermentation at a temperature range of 50-70 degrees C with exogenously added ethanol up to approximately 6.4% (v/v). At the optimum growth temperature of 70 degrees C, the strain was able to tolerate 4.7% (v/v) ethanol, and growth was completely inhibited at 5.6% (v/v). A higher ethanol tolerance was found at lower temperatures. At 60 degrees C, the strain was able to tolerate at least 5.1% (v/v) ethanol. A generalized form of Monod kinetic equation proposed by Levenspiel was used to describe the ethanol (product) inhibition. The model predicted quite well the experimental data for the temperature interval 50-70 degrees C, and the maximum specific growth rate and the toxic power (n), which describes the order of ethanol inhibition at each temperature, were estimated. The toxic power (n) was 1.33 at 70 degrees C, and corresponding critical inhibitory product concentration (P(crit)) above which no microbial growth occurs was determined to be 5.4% (v/v). An analysis of toxic power (n) and P(crit) showed that the optimum temperature for combined microbial growth and ethanol tolerance was 60 degrees C. At this temperature, the toxic power (n), and P(crit) were 0.50, and 6.5% (v/v) ethanol, respectively. From a practical point of view, the model may be applied to compare the ethanol inhibition (ethanol tolerance) on microbial growth of different thermophilic anaerobic bacterial strains.

  1. Mesophilic and thermophilic anaerobic digestion of municipal sludge and fat, oil, and grease.

    PubMed

    Kabouris, John C; Tezel, Ulas; Pavlostathis, Spyros G; Engelmann, Michael; Dulaney, James A; Todd, Allen C; Gillette, Robert A

    2009-05-01

    The anaerobic biodegradability of municipal primary sludge, thickened waste activated sludge (TWAS), and fat, oil, and grease (FOG) was assessed using semi-continuous-feed, laboratory-scale anaerobic digesters and compared with the ultimate degradability obtained from 120-day batch digestion at 35 degrees C. In run 1, combined primary sludge and TWAS (40/60%, volatile solids [VS] basis) were fed to digesters operated at mesophilic (35 degrees C) and thermophilic (52 degrees C) temperatures at loading rates of 0.99 and 1.46 g-VS/L x d for primary sludge and TWAS, respectively, and a hydraulic retention time (HRT) of 12 days. The volatile solids destruction values were 25.3 and 30.7% (69 and 83% biodegradable volatile solids destruction) at 35 degrees C and 52 degrees C, respectively. The methane (CH4) yields were 159 and 197 mL at the standard temperature and pressure (STP) conditions of 0 degree C and 1 atm/g-VS added or 632 and 642 mL @ STP/g-VS destroyed at 35 degrees C and 52 degrees C, respectively. In run 2, a mix of primary sludge, TWAS, and FOG (21/31/48%, volatile solids basis) was fed to an acid digester operated at a 1-day HRT, at 35 degrees C, and a loading rate of 52.5 g-VS/L x d. The acid-reactor effluent was fed to two parallel methane-phase reactors operated at an HRT of 12 days and maintained at 35 degrees C and 52 degrees C, respectively. After an initial period of 20 days with near-zero gas production in the acid reactor, biogas production increased and stabilized to approximately 2 mL CH4 @ STP/g-VS added, corresponding to a volatile solids destruction of 0.4%. The acid-phase reactor achieved a 43% decrease in nonsaturated fat and a 16, 26, and 20% increase of soluble COD, volatile fatty acids, and ammonia, respectively. The methane-phase volatile solids destruction values in run 2 were 45 and 51% (85 and 97% biodegradable volatile solids destruction) at 35 degrees C and 52 degrees C, respectively. The methane yields for the methane

  2. Anaerobic co-digestion of steam-treated Quercus serrata chips and sewage sludge under mesophilic and thermophilic conditions.

    PubMed

    Wang, Feng; Hidaka, Taira; Sakurai, Kensuke; Tsumori, Jun

    2014-08-01

    The biodegradation of Quercus serrata chips was evaluated by anaerobic digestion under various steam explosion conditions. In continuous experiments, untreated chips (W₀) and chips steam-treated at less than 1.0 MPa (W₁) and 2.0 MPa (W₄) were co-digested with sewage sludge (S₁ and S₂) taken from two different wastewater treatment plants. The apparent methane yield of W₁ and W₄ co-digested with S₁ (thermophilic) was 261 dm(3)/kgVS (volatile solids) and 248 dm(3)/kgVS, respectively. The apparent methane yield of W₄ co-digested with S₂ was 258 dm(3)/kgVS (mesophilic) and 271 dm(3)/kgVS (thermophilic). Methane production was inhibited by W₀ due to components released during hydrolysis. The methane conversion ratio of pretreated chips obtained in batch experiments varied from 40.5% to 53.8% (mesophilic) and from 49.0% to 63.7% (thermophilic). The methane conversion ratio increased with decreasing acid-soluble lignin content in the chips.

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

    PubMed

    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.

  4. Novel chemolithotrophic, thermophilic, anaerobic bacteria Thermolithobacter ferrireducens gen. nov., sp. nov. and Thermolithobacter carboxydivorans sp. nov.

    PubMed

    Sokolova, T; Hanel, J; Onyenwoke, R U; Reysenbach, A-L; Banta, A; Geyer, R; González, J M; Whitman, W B; Wiegel, J

    2007-01-01

    Three thermophilic strains of chemolithoautotrophic Fe(III)-reducers were isolated from mixed sediment and water samples (JW/KA-1 and JW/KA-2(T): Calcite Spring, Yellowstone N.P., WY, USA; JW/JH-Fiji-2: Savusavu, Vanu Levu, Fiji). All were Gram stain positive rods (approximately 0.5 x 1.8 microm). Cells occurred singly or in V-shaped pairs, and they formed long chains in complex media. All utilized H(2) to reduce amorphous iron (III) oxide/hydroxide to magnetite at temperatures from 50 to 75 degrees C (opt. approximately 73 degrees C). Growth occurred within the pH(60C) range of 6.5-8.5 (opt. pH(60C) 7.1-7.3). Magnetite production by resting cells occurred at pH(60C) 5.5-10.3 (opt. 7.3). The iron (III) reduction rate was 1.3 mumol Fe(II) produced x h(-1) x ml(-1) in a culture with 3 x 10(7) cells, one of the highest rates reported. In the presence or absence of H(2), JW/KA-2(T) did not utilize CO. The G + C content of the genomic DNA of the type strain is 52.7 +/- 0.3 mol%. Strains JW/KA-1 and JW/KA-2(T) each contain two different 16S rRNA gene sequences. The 16S rRNA gene sequences from JW/KA-1, JW/KA-2(T), or JW/JH-Fiji-2 possessed >99% similarity to each other but also 99% similarity to the 16S rRNA gene sequence from the anaerobic, thermophilic, hydrogenogenic CO-oxidizing bacterium 'Carboxydothermus restrictus' R1. DNA-DNA hybridization between strain JW/KA-2(T) and strain R1(T) yielded 35% similarity. Physiological characteristics and the 16S rRNA gene sequence analysis indicated that the strains represent two novel species and are placed into the novel genus Thermolithobacter within the phylum 'Firmicutes'. In addition, the levels of 16S rRNA gene sequence similarity between the lineage containing the Thermolithobacter and well-established members of the three existing classes of the 'Firmicutes' is less than 85%. Therefore, Thermolithobacter is proposed to constitute the first genus within a novel class of the 'Firmicutes', Thermolithobacteria. The Fe

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

    PubMed

    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.

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

    PubMed

    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.

  7. Thermanaeromonas burensis sp. nov., a thermophilic anaerobe isolated from a subterranean clay environment.

    PubMed

    Gam, Zouhaier Ben Ali; Daumas, Sylvie; Casalot, Laurence; Bartoli-Joseph, Manon; Necib, Sophia; Linard, Yannick; Labat, Marc

    2016-01-01

    A strictly anaerobic, thermophilic and halotolerant strain, designated IA106T, was isolated from the seepage water collected in a metal biocorrosion test at a depth of 490 m, in a 130-160 m thick, subterranean Callovo-Oxfordian clay formation (158-152 million years old) in northern France. This geological formation has been selected as the potential host rock for the French high-level nuclear waste repository. Cells of strain IA106T stained Gram-positive and were non-motile, spore-forming, straight rods (0.5 × 2-6 μm). The five major fatty acids were C16 : 0 (15.9 %), C18 : 0 (15.4 %), iso-C17 : 1 I and/or anteiso-C17 : 1 B(14.8 %), iso-C17 : 0 (14.7 %) and iso-C15 : 0 (13.0 %). Growth was observed at temperatures ranging from 55 to 70 °C and at pH 5.5-9. The salinity range for growth was 0-20 g NaCl 1- 1. Yeast extract was required for growth. Strain IA106T was able to grow on lactate and various sugars in the presence of thiosulfate as electron acceptor. Sulfate, sulfite, elemental sulfur, fumarate, nitrate and nitrite were not reduced. The DNA G+C content was 60.2 mol%. 16S rRNA gene sequence analysis indicated that strain IA106T belonged to the family Thermoanaerobacteraceae, class Clostridia, phylum Firmicutes, and was most closely related to Thermanaeromonas toyohensis DSM 14490T (95.16 % 16S rRNA gene sequence similarity). On the basis of 16S rRNA gene sequence comparisons and physiological characteristics, strain IA106T represents a novel species of the genus Thermanaeromonas, for which the name Thermanaeromonas burensis sp. nov. is proposed. The type strain is IA106T ( = DSM 26576T = JCM 18718T).

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

    PubMed

    Ogg, Christopher D; Patel, Bharat K C

    2010-06-01

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

  9. Dry-thermophilic anaerobic digestion of organic fraction of municipal solid waste: Methane production modeling

    SciTech Connect

    Fdez-Gueelfo, L.A.; Alvarez-Gallego, C.; Sales, D.; Romero Garcia, L.I.

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Methane generation may be modeled by means of modified product generation model of Romero Garcia (1991). Black-Right-Pointing-Pointer Organic matter content and particle size influence the kinetic parameters. Black-Right-Pointing-Pointer Higher organic matter content and lower particle size enhance the biomethanization. - Abstract: The influence of particle size and organic matter content of organic fraction of municipal solid waste (OFMSW) in the overall kinetics of dry (30% total solids) thermophilic (55 Degree-Sign C) anaerobic digestion have been studied in a semi-continuous stirred tank reactor (SSTR). Two types of wastes were used: synthetic OFMSW (average particle size of 1 mm; 0.71 g Volatile Solids/g waste), and OFMSW coming from a composting full scale plant (average particle size of 30 mm; 0.16 g Volatile Solids/g waste). A modification of a widely-validated product-generation kinetic model has been proposed. Results obtained from the modified-model parameterization at steady-state (that include new kinetic parameters as K, Y{sub pMAX} and {theta}{sub MIN}) indicate that the features of the feedstock strongly influence the kinetics of the process. The overall specific growth rate of microorganisms ({mu}{sub max}) with synthetic OFMSW is 43% higher compared to OFMSW coming from a composting full scale plant: 0.238 d{sup -1} (K = 1.391 d{sup -1}; Y{sub pMAX} = 1.167 L CH{sub 4}/gDOC{sub c}; {theta}{sub MIN} = 7.924 days) vs. 0.135 d{sup -1} (K = 1.282 d{sup -1}; Y{sub pMAX} = 1.150 L CH{sub 4}/gDOC{sub c}; {theta}{sub MIN} = 9.997 days) respectively. Finally, it could be emphasized that the validation of proposed modified-model has been performed successfully by means of the simulation of non-steady state data for the different SRTs tested with each waste.

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

    PubMed Central

    2012-01-01

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

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

    PubMed

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

    2013-04-01

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

  12. Distribution of methanogenic potential in fractions of turf grass used as inoculum for the start-up of thermophilic anaerobic digestion.

    PubMed

    Suwannoppadol, Suwat; Ho, Goen; Cord-Ruwisch, Ralf

    2012-08-01

    This study aims to investigate thermophilic methanogens in turf used as an inoculum. Results showed that Methanoculleus sp. regarded as hydrogenotrophic and Methanosarcina sp. regarded as acetoclastic methanogens were present in turf tested. However, active acetoclastic methanogens were present in turf soil only. The current study showed that thermophilic methanogens were present in various turf grass species: Stenotaphrum secundatum, Cynodon dactylon, and Zoysia japonica. Severe treatments of grass leaves under oxic conditions, including blending, drying and pulverizing did not affect the thermophilic hydrogenotrophic methanogenic activity of the grass. A dried and pulverized grass extract could be generated that can serve as a readily storable methanogenic inoculum for thermophilic anaerobic digestion. The methanogens could also be physically extracted into an aqueous suspension, suitable as an inoculum. The possible contribution of the presence of methanogens on grass plants to global greenhouse emissions is briefly discussed.

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

    PubMed

    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.

  14. Draft Genome Sequence of Paenibacillus Strain P1XP2, a Polysaccharide-Degrading, Thermophilic, Facultative Anaerobic Bacterium Isolated from a Commercial Bioreactor Degrading Food Waste

    PubMed Central

    Adelskov, Joseph

    2015-01-01

    The analysis of the ~5.8-Mb draft genome sequence of a moderately thermophilic, heterotrophic, facultative anaerobic bacterium, Paenibacillus strain P1XP2, identified genes for enzymes with the potential for degrading complex food wastes, a property consistent with the ecological habitat of the isolate. PMID:25635015

  15. Draft Genome Sequence of Paenibacillus Strain P1XP2, a Polysaccharide-Degrading, Thermophilic, Facultative Anaerobic Bacterium Isolated from a Commercial Bioreactor Degrading Food Waste.

    PubMed

    Adelskov, Joseph; Patel, Bharat K C

    2015-01-29

    The analysis of the ~5.8-Mb draft genome sequence of a moderately thermophilic, heterotrophic, facultative anaerobic bacterium, Paenibacillus strain P1XP2, identified genes for enzymes with the potential for degrading complex food wastes, a property consistent with the ecological habitat of the isolate.

  16. Comparison of mesophilic and thermophilic anaerobic digestion of sugar beet pulp: performance, dewaterability and foam control.

    PubMed

    Suhartini, Sri; Heaven, Sonia; Banks, Charles J

    2014-01-01

    Digestion of sugar beet pulp was assessed in relation to biogas and methane production, foaming potential, and digestate dewaterability. Four 4-litre working volume digesters were operated mesophilically (37±0.5 °C) and four thermophilically (55±0.5 °C) over three hydraulic retention times. Digesters were operated in duplicate at organic loading rates (OLR) of 4 and 5 g volatile solids l(-1) day(-1) without water addition. Thermophilic digestion gave higher biogas and methane productivity than mesophilic and was able to operate at the higher OLR, where mesophilic digestion showed signs of instability. Digestate dewaterability was assessed using capillary suction time and frozen image centrifugation. The occurrence of, or potential for, stable foam formation was assessed using a foaming potential test. Thermophilic operation allowed higher loadings to be applied without loss of performance, and gave a digestate with superior dewatering characteristics and very little foaming potential.

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

    PubMed

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

    2015-02-01

    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 100g/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 52.9L/kg VS (volatile solid) for the total solid (TS) concentration of 100g/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).

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

    SciTech Connect

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

    2015-02-15

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

  19. Thermophilic anaerobic digestion of pulp and paper mill primary sludge and co-digestion of primary and secondary sludge.

    PubMed

    Bayr, Suvi; Rintala, Jukka

    2012-10-01

    Anaerobic digestion of pulp and paper mill primary sludge and co-digestion of primary and secondary sludge were studied for the first time in semi-continuously fed continuously stirred tank reactors (CSTR) in thermophilic conditions. Additionally, in batch experiments, methane potentials of 210 and 230 m³CH₄/t volatile solids (VS)(added) were obtained for primary, and 50 and 100 m³CH₄/tVS(added) for secondary sludge at 35 °C and 55 °C, respectively. Anaerobic digestion of primary sludge was shown to be feasible with organic loading rates (OLR) of 1-1.4 kgVS/m³d and hydraulic retention times (HRT) of 16-32 d resulting in methane yields of 190-240 m³CH₄/tVS(fed). Also the highest tested OLR of 2 kgVS/m³d and the shortest HRT of 14-16 d could be feasible, if pH stability is confirmed. Co-digestion of primary and secondary sludge with an OLR of 1 kgVS/m³d and HRTs of 25-31 d resulted in methane yields of 150-170 m³CH₄/tVS(fed). In the digestion processes, cellulose and hemicellulose degraded while lignin did not. pH adjustment and nitrogen deficiency needs to be considered when planning anaerobic digestion of pulp and paper mill wastewater sludges.

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

    PubMed

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

    2016-09-01

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

  1. Thermophilic anaerobic digestion of thermal pretreated sludge: role of microbial community structure and correlation with process performances.

    PubMed

    Gagliano, M C; Braguglia, C M; Gianico, A; Mininni, G; Nakamura, K; Rossetti, S

    2015-01-01

    Thermal hydrolysis pretreatment coupled with Thermophilic Anaerobic Digestion (TAD) for Waste Activated Sludge (WAS) treatment is a promising combination to improve biodegradation kinetics during stabilization. However, to date there is a limited knowledge of the anaerobic biomass composition and its impact on TAD process performances. In this study, the structure and dynamics of the microbial communities selected in two semi-continuous anaerobic digesters, fed with untreated and thermal pretreated sludge, were investigated. The systems were operated for 250 days at different organic loading rate. 16S rRNA gene clonal analysis and Fluorescence In Situ Hybridization (FISH) analyses allowed us to identify the majority of bacterial and archaeal populations. Proteolytic Coprothermobacter spp. and hydrogenotrophic Methanothermobacter spp. living in strict syntrophic association were found to dominate in TAD process. The establishment of a syntrophic proteolytic pathway was favoured by the high temperature of the process and enhanced by the thermal pretreatment of the feeding sludge. Proteolytic activity, alone or with thermal pretreatment, occurred during TAD as proven by increasing concentration of soluble ammonia and soluble COD (sCOD) during the process. However, the availability of a readily biodegradable substrate due to pretreatment allowed to significant sCOD removals (more than 55%) corresponding to higher biogas production in the reactor fed with thermal pretreated sludge. Microbial population dynamics analysed by FISH showed that Coprothermobacter and Methanothermobacter immediately established a stable syntrophic association in the reactor fed with pretreated sludge in line with the overall improved TAD performances observed under these conditions.

  2. Anaerobic Biodegradation Tests of Poly(lactic acid) under Mesophilic and Thermophilic Conditions Using a New Evaluation System for Methane Fermentation in Anaerobic Sludge

    PubMed Central

    Yagi, Hisaaki; Ninomiya, Fumi; Funabashi, Masahiro; Kunioka, Masao

    2009-01-01

    Anaerobic biodegradation tests of poly(lactic acid) (PLA) powder were done at the thermophilic (55 °C) and mesophilic temperature (35 °C) under aquatic conditions [total solid concentrations of the used sludge were 2.07% (at 55 °C) and 2.24% (at 35 °C)] using a newly developed evaluation system. With this system, the evolved biogas is collected in a gas sampling bag at atmospheric pressure. This method is more convenient than using a pressure transducer or inverted graduated cylinder submerged in water. PLA was degraded about 60% in 30 days, about 80% in 40 days and about 90% in 60 days at 55 °C. On the other hand, the PLA degradation started in 55 days at 35 °C and degradation rate was much slower than at 55 °C. PMID:19865521

  3. Anaerobic biodegradation tests of poly(lactic acid) under mesophilic and thermophilic conditions using a new evaluation system for methane fermentation in anaerobic sludge.

    PubMed

    Yagi, Hisaaki; Ninomiya, Fumi; Funabashi, Masahiro; Kunioka, Masao

    2009-09-02

    Anaerobic biodegradation tests of poly(lactic acid) (PLA) powder were done at the thermophilic (55 degrees C) and mesophilic temperature (35 degrees C) under aquatic conditions [total solid concentrations of the used sludge were 2.07% (at 55 degrees C) and 2.24% (at 35 degrees C)] using a newly developed evaluation system. With this system, the evolved biogas is collected in a gas sampling bag at atmospheric pressure. This method is more convenient than using a pressure transducer or inverted graduated cylinder submerged in water. PLA was degraded about 60% in 30 days, about 80% in 40 days and about 90% in 60 days at 55 degrees C. On the other hand, the PLA degradation started in 55 days at 35 degrees C and degradation rate was much slower than at 55 degrees C.

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

    PubMed

    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.

  5. Caloramator australicus sp. nov., a thermophilic, anaerobic bacterium from the Great Artesian Basin of Australia.

    PubMed

    Ogg, Christopher D; Patel, Bharat K C

    2009-01-01

    A strictly anaerobic, thermophilic bacterium, designated strain RC3T, was isolated from microbial mats colonizing thermal waters of a run-off channel formed by free-flowing waters from a bore well (registered no. 17263) of the Great Artesian Basin, Australia. The slightly curved rods (2.5-4.2x0.8-1.0 microm) of strain RC3T stained Gram-positive and grew optimally in tryptone-yeast extract-glucose medium at 60 degrees C (range 45-70 degrees C) and pH 7 (range pH 5-9). Strain RC3T grew poorly on yeast extract (0.2 %) but did not grow on tryptone (0.2 %) as a sole carbon source; yeast extract was required for growth on other energy sources, which included glucose, fructose, galactose, xylose, maltose, sucrose, raffinose, mannose, cellobiose, cellulose, starch, amylopectin, xylan, peptone, amyl media (Research Achievement), threonine and pyruvate but did not include arabinose, ribose, lactose, CM-cellulose, myo-inositol, mannitol, chitin, casein, formate, acetate, succinate, propionate, lactate, benzoate, glycerol, ethanol, Casamino acids, arginine, alanine, serine, glycine, glutamine, leucine, isoleucine, methionine or aspartate. The end products of glucose fermentation were ethanol and acetate. In the presence of 0.2 % yeast extract, iron(III), manganese(IV) and elemental sulfur were reduced but not sulfate, sulfite, thiosulfate, nitrate or nitrite. Iron(III) was also reduced in the presence of peptone, tryptone, amyl media, threonine and glycerol but not chitin, xylan, pectin, starch, pyruvate, acetate, benzoate, lactate, propionate, succinate, inositol, ethanol, mannitol, arginine, glutamine or serine. Strain RC3T was not able to utilize molecular hydrogen and/or carbon dioxide in the presence or absence of iron(III). In the presence of iron(III) and glycerol, increased concentrations of Fe(II) corresponded to increased cell numbers, demonstrating that strain RC3(T) was able to conserve energy to support growth from the reduction of Fe(III) to Fe

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

    PubMed

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

    2014-06-01

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

  7. Conventional heating vs. microwave sludge pretreatment comparison under identical heating/cooling profiles for thermophilic advanced anaerobic digestion.

    PubMed

    Hosseini Koupaie, E; Eskicioglu, C

    2016-07-01

    This research evaluates whether there is any advantage of selecting one of the thermal methods of sludge pretreatment, conventional heating (CH) and microwave hydrolysis (MW), over another to enhance municipal sludge disintegration and performance of thermophilic anaerobic digestion (AD). For this purpose, a custom-built CH system simulating MW hydrolysis under identical heating and cooling profiles was used. The effects of three main pretreatment parameters including pretreatment method (CH and MW), heating ramp rate (3, 6 and 11°C/min) and final temperature (80, 120 and 160°C) on sludge solubilization and performance of thermophilic batch AD were evaluated. The effects of CH and MW hydrolysis were observed to be similar for sludge disintegration and digester performance (p-value>0.05), while the effects of final temperature and heating ramp rate were proven to be different (p-value<0.05). According to the results, it is essential to apply MW and CH pretreatments under identical experimental condition for an unbiased comparison which supports the findings of the author's earlier study under mesophilic condition. Failing to address this issue explains the significant inconsistency observed among the findings of the previous CH vs. MW comparison studies that were unable to implement identical thermal profiles (between CH and MW) during sludge pretreatment. In comparison with mesophilic AD, thermophilic AD revealed lower biodegradation rate constant at the highest pretreatment temperature tested (160°C), suggesting its higher sensitivity to the inhibitory effects of thermal pretreatment at the elevated temperatures. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Evaluation of biodegradability of phenol and bisphenol A during mesophilic and thermophilic municipal solid waste anaerobic digestion using 13C-labeled contaminants.

    PubMed

    Limam, Intissar; Mezni, Mohamed; Guenne, Angéline; Madigou, Céline; Driss, Mohamed Ridha; Bouchez, Théodore; Mazéas, Laurent

    2013-01-01

    In this paper, the isotopic tracing using (13)C-labeled phenol and bisphenol A was used to study their biodegradation during anaerobic digestion of municipal solid waste. Microcosms were incubated anaerobically at 35 °C (mesophilic conditions) and 55 °C (thermophilic conditions) without steering. A continuous follow-up of the production of biogas (CH(4) and CO(2)), was carried out during 130 d until the establishment of stable methanogenesis. Then (13)C(12)-BPA, and (13)C(6)-phenol were injected in microcosms and the follow-up of their degradation was performed simultaneously by gas chromatography isotope-ratio mass spectrometry (GC-IRMS) and gas chromatography mass spectrometry (GC-MS). Moreover, Carbon-13 Nuclear Magnetic Resonance ((13)C-NMR) Spectroscopy is used in the identification of metabolites. This study proves that the mineralization of phenol to CO(2) and CH(4) occurs during anaerobic digestion both in mesophilic and thermophilic conditions with similar kinetics. In mesophilic condition phenol degradation occurs through the benzoic acid pathway. In thermophilic condition it was not possible to identify the complete metabolic pathway as only acetate was identified as metabolite. Our results suggest that mineralization of phenol under thermophilic condition is instantaneous explaining why metabolites are not observed as they do not accumulate. No biodegradation of BPA was observed.

  9. Population dynamics of anaerobic microbial consortia in thermophilic granular sludge in response to feed composition change.

    PubMed

    Syutsubo, K; Sinthurat, N; Ohashi, A; Harada, H

    2001-01-01

    A thermophilic UASB reactor was operated at 55 degrees C for greater than 470 days in order to investigate the effects of feed composition on the changes in microbial community structure where thermophilic granular sludge was used as the inoculum source. The feed compositions were changed with cultivation days; phase 1 (1-70 days), alcohol distillery wastewater; phase 2 (71-281 days), artificial acetate wastewater; phase 3 (282-474 days), artificial sucrose wastewater. During the first one month of each phase, the methanogenic activity and cell density of methanogens quantified by fluorescence in situ hybridization (FISH) drastically changed as a result of shift in feed composition. When artificial acetate wastewater was used as feed, retained granular sludge was partially disintegrated due to a decrease in the number of symbiotic bacterial community members: acetogens (acidogens) and hydrogenotrophic methanogens. In contrast, when the feed was shifted to sucrose (phase 3), granulation of biomass was promoted by a remarkable proliferation of the symbiotic community. The presence of hydrogen-utilizing methanogens and acetogens (acidogens) are shown to be effective for the enhancement of thermophilic granulation. The cell density of methanogens determined by FISH was strongly correlated with the methane-producing potential of the retained thermophilic granular sludge.

  10. Change of PCBs and forms of heavy metals in sewage sludge during thermophilic anaerobic digestion.

    PubMed

    Dąbrowska, Lidia; Rosińska, Agata

    2012-06-01

    Determination of seven congeners of PCBs was carried out for sewage sludge before, during and after thermophilic digestion. The overall content of heavy metals (Zn, Cu, Ni, Cd, Pb, Cr) in sludge before and after digestion was determined. Moreover the concentration of heavy metals in particular chemical fractions of the sludge was analyzed. After the thermophilic digestion total concentration of seven PCBs was reduced by 47%, which suggests that thermophilic digestion affects PCB reduction positively. On the 10th d of the process, concentration of lower chlorinated PCBs increased, whereas those of higher chlorinated PCBs decreased. The thermophilic digestion process showed no accumulation of the studied heavy metals in the mobile fractions (exchangeable and carbonate) of the stabilized sewage sludge, except for nickel. The highest increase in zinc, copper, cadmium, and chromium concentration was observed in the organic-sulfide fraction, whereas the highest increase in lead was found in the residual fraction of the sludge. In case of nickel both fractions of organic-sulfide and exchangeable-carbonate fractions were enriched.

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

    PubMed

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

    2016-02-01

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

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

    PubMed

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

    2011-03-15

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

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

    PubMed

    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 (H2S) 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% H2S 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.

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

    PubMed

    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.

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

    PubMed Central

    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 low levels of CO are reached. Here we study CO conversion and final CO levels in cultures of C. hydrogenoformans grown in batch cultures that were started with a 100% CO gas phase with and without removal of formed CO2. Final CO levels were 117 ppm without CO2 removal and below 2 ppm with CO2 removal. The Gibbs free energy change calculated with measured end concentrations and the detection of acetate suggest that C. hydrogenoformans shifted from a hydrogenogenic to an acetogenic metabolism. PMID:21754940

  16. Diversity of anaerobic heterotrophic thermophiles isolated from deep-sea hydrothermal vents of the Mid-Atlantic Ridge.

    PubMed

    Wery, Nathalie; Cambon-Bonavita, Marie-Anne; Lesongeur, Françoise; Barbier, Georges

    2002-08-01

    Abstract During the 'MARVEL' oceanographical cruise performed in September 1997, samples were collected from the deep-sea vents of hydrothermal sites on the Mid-Atlantic Ridge. Eighty-four thermophilic and hyperthermophilic heterotrophic microorganisms were isolated using different culture media containing cellobiose, xylan, starch, lipidic or proteic substrates. These isolates were obtained in anaerobic conditions, at 65 degrees C, 85 degrees C and 95 degrees C. Fifty of them were classified using amplified ribosomal DNA restriction analysis, random amplified polymorphic DNA and 16S rDNA sequencing. The strains classified have been assigned to the archaeal order Thermococcales and to the bacterial orders Thermotogales and Clostridiales. Variations in growth temperature and carbon sources were efficient enough to generate taxonomic diversity within enrichment cultures. Presumptive new genera and new species were isolated. Two isolates were confirmed as type strains of new species of new genera recently described: Marinitoga camini and Caloranaerobacter azorensis.

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

    PubMed

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

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

    PubMed

    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

  19. Chemical Changes during Anaerobic Decomposition of Hardwood, Softwood, and Old Newsprint under Mesophilic and Thermophilic Conditions

    Treesearch

    Florentino B. De la Cruz; Daniel J. Yelle; Hanna S. Gracz; Morton A. Barlaz

    2014-01-01

    The anaerobic decomposition of plant biomass is an important aspect of global organic carbon cycling. While the anaerobic metabolism of cellulose and hemicelluloses to methane and carbon dioxide are well-understood, evidence for the initial stages of lignin decomposition is fragmentary. The objective of this study was to look for evidence of chemical transformations of...

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

    SciTech Connect

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

    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.

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

    PubMed

    Wang, Han; Zhang, Yifeng; Angelidaki, Irini

    2016-11-15

    Capturing of carbon dioxide by hydrogen derived from excess renewable energy (e.g., wind mills) to methane in a microbially catalyzed process offers an attractive technology for biogas production and upgrading. This bioconversion process is catalyzed by hydrogenotrophic methanogens, which are known to be sensitive to ammonia. In this study, the tolerance of the biogas process under supply of hydrogen, to ammonia toxicity was studied under mesophilic and thermophilic conditions. When the initial hydrogen partial pressure was 0.5 atm, the methane yield at high ammonia load (7 g NH4(+)-N L(-1)) was 41.0% and 22.3% lower than that at low ammonia load (1 g NH4(+)-N L(-1)) in mesophilic and thermophilic condition, respectively. Meanwhile no significant effect on the biogas composition was observed. Moreover, we found that hydrogentrophic methanogens were more tolerant to the ammonia toxicity than acetoclastic methanogens in the hydrogen enriched biogas production and upgrading processes. The highest methane production yield was achieved under 0.5 atm hydrogen partial pressure in batch reactors at all the tested ammonia levels. Furthermore, the thermophilic methanogens at 0.5 atm of hydrogen partial pressure were more tolerant to high ammonia levels (≥5 g NH4(+)-N L(-1)), compared with mesophilic methanogens. The present study offers insight in developing resistant hydrogen enriched biogas production and upgrading processes treating ammonia-rich waste streams.

  2. Respiratory Ammonification of Nitrate Coupled to Anaerobic Oxidation of Elemental Sulfur in Deep-Sea Autotrophic Thermophilic Bacteria

    PubMed Central

    Slobodkina, Galina B.; Mardanov, Andrey V.; Ravin, Nikolai V.; Frolova, Anastasia A.; Chernyh, Nikolay A.; Bonch-Osmolovskaya, Elizaveta A.; Slobodkin, Alexander I.

    2017-01-01

    Respiratory ammonification of nitrate is the microbial process that determines the retention of nitrogen in an ecosystem. To date, sulfur-dependent dissimilatory nitrate reduction to ammonium has been demonstrated only with sulfide as an electron donor. We detected a novel pathway that couples the sulfur and nitrogen cycles. Thermophilic anaerobic bacteria Thermosulfurimonas dismutans and Dissulfuribacter thermophilus, isolated from deep-sea hydrothermal vents, grew autotrophically with elemental sulfur as an electron donor and nitrate as an electron acceptor producing sulfate and ammonium. The genomes of both bacteria contain a gene cluster that encodes a putative nitrate ammonification enzyme system. Nitrate reduction occurs via a Nap-type complex. The reduction of produced nitrite to ammonium does not proceed via the canonical Nrf system because nitrite reductase NrfA is absent in the genomes of both microorganisms. The genome of D. thermophilus encodes a complete sulfate reduction pathway, while the Sox sulfur oxidation system is missing, as shown previously for T. dismutans. Thus, in high-temperature environments, nitrate ammonification with elemental sulfur may represent an unrecognized route of primary biomass production. Moreover, the anaerobic oxidation of sulfur compounds coupled to growth has not previously been demonstrated for the members of Thermodesulfobacteria or Deltaproteobacteria, which were considered exclusively as participants of the reductive branch of the sulfur cycle. PMID:28194142

  3. Quantifying contribution of synthrophic acetate oxidation to methane production in thermophilic anaerobic reactors by membrane inlet mass spectrometry.

    PubMed

    Mulat, Daniel Girma; Ward, Alastair James; Adamsen, Anders Peter S; Voigt, Niels Vinther; Nielsen, Jeppe Lund; Feilberg, Anders

    2014-02-18

    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-(13)C] 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 of incubation, the proportion of methane derived from reduction of CO2 had increased significantly and reached up to 87% of total methane, suggesting that synthrophic acetate oxidation coupled to hydrogenotrophic methanogenesis (SAO-HM) played an important role in the degradation of acetate. This study provided 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 digestion model (ADM1), which strongly emphasizes the importance of the acetoclastic methanogenesis.

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

    PubMed

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

    2014-01-01

    Thermophilic and mesophilic anaerobic digestion reactors (TR and MR) using food waste as substrate were compared with emphasis on microbial responses to increasing organic loading rate (OLR). At OLR ranging from 1.0 to 2.5 g VS L(-1) d(-1), MR exhibited more stable performance compared to TR in terms of methane yield. Amplicons pyrosequencing results revealed the distinct microbial dynamics in the two reactors. Primarily, MR had greater richness and evenness of bacteria species. With OLR elevated, larger shifts of bacterial phylogeny were observed in MR; Methanosaeta dominated in archaeal community in MR while Methanothermobacter and Methanoculleus were favored in TR. The high functional redundancy in bacterial community integrated with acetoclastic methanogenesis in MR resulted in its better performance; whereas delicate interactions between hydrogen-producer and hydrogenotrophic methanogens in TR were much more prone to disruption. These results are conductive to understanding the microbial mechanisms of low methane yield during food waste anaerobic digestion. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

    PubMed

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

    2015-12-01

    Anaerobic digestion by two-stage process, containing hydrogen-producing (acidogenic) first stage and methanogenic second stage, has been proposed to degrade substrates which are difficult to be treated by single stage anaerobic digestion process. This research was aimed to evaluate the bio-hydrogen and the bio-methane potentials (BHP and BMP) of skim latex serum (SLS) by using sequential batch hydrogen and methane cultivations at thermophilic conditions (55°C) and with initial SLS concentrations of 37.5-75.0% (v/v). The maximal 1.57 L H2/L SLS for BHP and 12.2L CH4/L SLS for BMP were both achieved with 60% (v/v) SLS. The dominant hydrogen-producing bacteria in the H2 batch reactor were Thermoanaerobacterium sp. and Clostrdium sp. Meanwhile, the CH4 batch reactor was dominated by the methanogens Methanosarcina mazei and Methanothermobacter defluvii. The results demonstrate that SLS can be degraded by conversion to form hydrogen and methane, waste treatment and bioenergy production are thus combined. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    PubMed Central

    Benner, Ronald; Hodson, Robert E.

    1985-01-01

    Thermophilic (55°C) anaerobic enrichment cultures were incubated with [14C-lignin]lignocellulose, [14C-polysaccharide]lignocellulose, and kraft [14C]lignin prepared from slash pine, Pinus elliottii, and 14C-labeled preparations of synthetic lignin and purified cellulose. Significant but low percentages (2 to 4%) of synthetic and natural pine lignin were recovered as labeled methane and carbon dioxide during 60-day incubations, whereas much greater percentages (13 to 23%) of kraft lignin were recovered as gaseous end products. Percentages of label recovered from lignin-labeled substrates as dissolved degradation products were approximately equal to percentages recovered as gaseous end products. High-pressure liquid chromatographic analyses of CuO oxidation products of sound and degraded pine lignin indicated that no substantial chemical modifications of the remaining lignin polymer, such as demethoxylation and dearomatization, occurred during biodegradation. The polysaccharide components of pine lignocellulose and purified cellulose were relatively rapidly mineralized to methane and carbon dioxide; 31 to 37% of the pine polysaccharides and 56 to 63% of the purified cellulose were recovered as labeled gaseous end products. An additional 10 to 20% of the polysaccharide substrates was recovered as dissolved degradation products. Overall, these results indicate that elevated temperatures can greatly enhance rates of anaerobic degradation of lignin and lignified substrates to methane and low-molecular-weight aromatic compounds. PMID:16346924

  7. Changes in bacterial community during fermentative hydrogen and acid production from organic waste by thermophilic anaerobic microflora.

    PubMed

    Ueno, Y; Sasaki, D; Fukui, H; Haruta, S; Ishii, M; Igarashi, Y

    2006-08-01

    Changes in fermentation pattern during the treatment of organic wastes containing solid materials by thermophilic anaerobic microflora were investigated with respect to product formation and bacterial community structure during hydrogen production. Anaerobic microflora enriched from sludge compost was cultivated using artificial garbage slurry in a continuous flow-stirred tank reactor. Product formation varied depending on pH and hydraulic retention time (HRT) applied. Community analysis by terminal restriction fragment length polymorphism and clone library analysis of polymerase chain reaction-amplified bacterial 16S rDNA indicated that difference in the fermentative product distribution could be caused by different populations of micro-organisms in the microflora. Hydrogen fermentation with acetate/butyrate formation was optimized at <1.0 d HRT at pH 5.0 and 6.0. Thermoanaerobacterium thermosaccharolyticum was the dominant hydrogen-producing micro-organism. Conversely, unidentified organisms became dominant after 4.0 d HRT at pH 7.0 and 8.0, where relatively high-solubilization efficiency of solid materials was observed with no production of hydrogen. This is the first report describing product formation in the fermentation of solid organic wastes by a mixed population of micro-organisms. Various fermentation patterns including hydrogen fermentation were characterized and evaluated from engineering and microbial aspects.

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

    PubMed

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

    2009-03-01

    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 0.04x10(-8) mLCH(4) cell(-1)day(-1) to 0.38x10(-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 0.64x10(-8) mLCH(4) cell(-1)day(-1) and 0.33x10(-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.

  9. Volume ratios between the thermophilic and the mesophilic digesters of a temperature-phased anaerobic digestion system affect their performance and microbial communities.

    PubMed

    Lv, Wen; Zhang, Wenfei; Yu, Zhongtang

    2016-01-25

    An experimental temperature-phased anaerobic digestion (TPAD) system, with the thermophilic digester operated at neutral pH and with a balanced acidogenesis and methanogenesis (referred to as NT-TPAD), was evaluated with respect to the microbial communities and population dynamics of methanogens when digesting dairy cattle manure at 15-day overall system hydraulic retention time (HRT). When fed a manure slurry of 10% total solid (TS), similar system performance, 36-38% volatile solid (VS) removal and 0.21-0.22 L methane g(-1) VS fed, was achieved between a 5-day and 7.5-day HRT for the thermophilic digester. However, the thermophilic digester achieved a greater volumetric biogas yield when operated at a 5-day RT than at a 7.5-day HRT (6.3 vs. 4.7 L/L/d), while the mesophilic digester had a stable volumetric biogas yield (about 1.0 L/L/d). Each of the digesters harbored distinct yet dynamic microbial populations, and some of the methanogens were significantly correlated with methane productions. Methanosarcina and Methanosaeta were the most important methanogenic genera in the thermophilic and the mesophilic digesters, respectively. The microbiological findings may help understand the metabolism that underpins the anaerobic processes within each of the two digesters of TPAD systems when fed dairy manure. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Addition of crude glycerine as strategy to balance the C/N ratio on sewage sludge thermophilic and mesophilic anaerobic co-digestion.

    PubMed

    Silvestre, G; Fernández, B; Bonmatí, A

    2015-10-01

    The effect of adding crude glycerine during continuous sewage sludge anaerobic digestion was investigated under thermophilic and mesophilic temperatures. Addition of CGY at thermophilic temperature range showed a negative impact on stability and performance of the process, even at low doses. The extreme pH values of CGY, together with the rapid release of VFA, causes SS alkalinity fail to control pH drop. On the contrary, at mesophilic temperature range the process performs steadily, with 148% increase in methane production when CGY represented 1% v/v of the influent (27% of influent COD). Further CGY percentages did not show any added improvement; the biomass shift, due to a high C/N ratio, could explain this behaviour. Results suggested that CGY can be used as co-substrate of SS anaerobic digestion though, depending on the characteristics of CGY, and on operational conditions, different parameters should be taken into account to achieve a steady and consistent operation.

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

    PubMed

    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.

  12. Mesophilic and thermophilic anaerobic laboratory-scale digestion of Nannochloropsis microalga residues.

    PubMed

    Kinnunen, H V; Koskinen, P E P; Rintala, J

    2014-03-01

    This paper studies methane production using a marine microalga, Nannochloropsis sp. residue from biodiesel production. Residue cake from Nannochloropsis, oils wet-extracted, had a methane potential of 482LCH4kg(-1) volatile solids (VS) in batch assays. However, when dry-extracted, the methane potential of residue cake was only 194LCH4kg(-1) VS. In semi-continuous reactor trials with dry-extracted residue cake, a thermophilic reactor produced 48% higher methane yield (220LCH4kg(-1)VS) than a mesophilic reactor (149LCH4kg(-1)VS). The thermophilic reactor was apparently inhibited due to ammonia with organic loading rate (OLR) of 2kgVSm(-3)d(-1) (hydraulic retention time (HRT) 46d), whereas the mesophilic reactor performed with OLR of 3kgVSm(-3)d(-1) (HRT 30d). Algal salt content did not inhibit digestion. Additional methane (18-33% of primary digester yield) was produced during 100d post-digestion.

  13. Biogeochemical Evidence that Thermophilic Archaea Mediate the Anaerobic Oxidation of Methane

    PubMed Central

    Schouten, Stefan; Wakeham, Stuart G.; Hopmans, Ellen C.; Sinninghe Damsté, Jaap S.

    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 the sediments suggests that microbes involved in anaerobic oxidation of methane are present and presumably active at environmental temperatures of >30°C, indicating that this process can occur not only at cold seeps but also at hydrothermal sites. The distribution of the membrane tetraether lipids of the methanotrophic archaea shows that these organisms have adapted their membrane composition to these high environmental temperatures. PMID:12620859

  14. Reorganization of the bacterial and archaeal populations associated with organic loading conditions in a thermophilic anaerobic digester.

    PubMed

    Hori, Tomoyuki; Haruta, Shin; Sasaki, Daisuke; Hanajima, Dai; Ueno, Yoshiyuki; Ogata, Atsushi; Ishii, Masaharu; Igarashi, Yasuo

    2015-03-01

    Organic loading conditions are an important factor influencing reactor performances in methanogenic bioreactors. Yet the underlying microbiological basis of the process stability, deterioration, and recovery remains to be understood. Here, structural responses of the bacterial and archaeal populations to the change of organic loading conditions in a thermophilic anaerobic digester were investigated by process analyses and 16S rRNA gene-based molecular approaches. The biogas was produced stably without the accumulation of volatile fatty acids (VFAs) at low organic loading rates (OLRs) in the beginning of reactor operation. Increasing OLR in stages disrupted the stable reactor performance, and high OLR conditions continued the deteriorated performance with slight biogas production and high accumulation of VFAs. Thereafter, the gradual decrease of OLR resulted in the recovery from the deterioration, giving rise to the stable performance again. The stable performances before and after the high OLR conditions conducted were associated with compositionally similar but not identical methanogenic consortia. The bacterial and archaeal populations were synchronously changed at both the transient phases toward the deteriorated performance and in recovery process, during which the dynamic shift of aceticlastic and hydrogenotrophic methanogens including the recently identified Methanomassiliicoccus might contribute to the maintenance of the methanogenic activity. The distinctive bacterial population with a high predominance of Methanobacterium formicicum as archaeal member was found for the deteriorated performance. The results in this study indicate the coordinated reorganization of the bacterial and archaeal populations in response to functional states induced by the change of organic loading conditions in the anaerobic digester. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

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

    SciTech Connect

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

    2010-01-01

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

  16. Unravelling the active microbial community in a thermophilic anaerobic digester-microbial electrolysis cell coupled system under different conditions.

    PubMed

    Cerrillo, Míriam; Viñas, Marc; Bonmatí, August

    2017-03-01

    Thermophilic anaerobic digestion (AD) of pig slurry coupled to a microbial electrolysis cell (MEC) with a recirculation loop was studied at lab-scale as a strategy to increase AD stability when submitted to organic and nitrogen overloads. The system performance was studied, with the recirculation loop both connected and disconnected, in terms of AD methane production, chemical oxygen demand removal (COD) and volatile fatty acid (VFA) concentrations. Furthermore, the microbial population was quantitatively and qualitatively assessed through DNA and RNA-based qPCR and high throughput sequencing (MiSeq), respectively to identify the RNA-based active microbial populations from the total DNA-based microbial community composition both in the AD and MEC reactors under different operational conditions. Suppression of the recirculation loop reduced the AD COD removal efficiency (from 40% to 22%) and the methane production (from 0.32 to 0.03 m(3) m(-3) d(-1)). Restoring the recirculation loop led to a methane production of 0.55 m(3) m(-3) d(-1) concomitant with maximum MEC COD and ammonium removal efficiencies of 29% and 34%, respectively. Regarding microbial analysis, the composition of the AD and MEC anode populations differed from really active microorganisms. Desulfuromonadaceae was revealed as the most active family in the MEC (18%-19% of the RNA relative abundance), while hydrogenotrophic methanogens (Methanobacteriaceae) dominated the AD biomass. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    PubMed

    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).

  18. Thermophilic treatment of acidified and partially acidified wastewater using an anaerobic submerged MBR: Factors affecting long-term operational flux.

    PubMed

    Jeison, D; van Lier, J B

    2007-09-01

    The long-term operation of two thermophilic anaerobic submerged membrane bioreactors (AnSMBRs) was studied using acidified and partially acidified synthetic wastewaters. In both reactors, cake formation was identified as the key factor governing critical flux. Even though cake formation was observed to be mostly reversible, particle deposition proceeds fast once the critical flux is exceeded. Very little irreversible fouling was observed during long-term operation, irrespective of the substrate. Critical flux values at the end of the reactors operation were 7 and 3L/m(2)h for the AnSMBRs fed with acidified and partially acidified wastewaters, respectively, at a gas superficial velocity of 70m/h. Small particle size was identified as the responsible parameter for the low observed critical flux values. The degree of wastewater acidification significantly affected the physical properties of the sludge, determining the attainable flux. Based on the fluxes observed in this research, the membrane costs would be in the range of 0.5euro/m(3) of treated wastewater. Gas sparging was ineffective in increasing the critical flux values. However, preliminary tests showed that cross-flow operation may be a feasible alternative to reduce particle deposition.

  19. Anaerobic thermophilic fermentation for carboxylic acid production from in-storage air-lime-treated sugarcane bagasse.

    PubMed

    Fu, Zhihong; Holtzapple, Mark T

    2011-06-01

    Wet storage and in situ lime pretreatment (50 °C, 1-atm air, 56 days, excess lime loading of 0.3 g Ca(OH)(2)/g dry biomass) of sugarcane bagasse (4,000 g dry weight) was performed in a bench-scale pile pretreatment system. Under thermophilic conditions (55 °C, NH(4)HCO(3) buffer, methane inhibitors), air-lime-treated bagasse (80 wt.%) and chicken manure (20 wt.%) were anaerobically co-digested in 1-L rotary fermentors by a mixed culture of marine microorganisms (Galveston, TX). During four-stage countercurrent fermentation, the resulting carboxylic acids consisted of primarily acetate (average 87.7 wt.%) and butyrate (average 9.0 wt.%). The experimental fermentation trains had the highest yield (0.47 g total acids/g volatile solids (VS) fed) and highest selectivity (0.79 g total acids/g VS digested) at a total acid concentration of 28.3 g/L, which is equivalent to an ethanol yield of 105.2 gal/(tonne VS fed). Both high total acid concentrations (>44.7 g/L) and high substrate conversions (>77.5%) are predicted for countercurrent fermentations of bagasse at commercial scale, allowing for an efficient conversion of air-lime-treated biomass to liquid transportation fuels and chemicals via the carboxylate platform.

  20. Thermodynamically enhancing propionic acid degradation by using sulfate as an external electron acceptor in a thermophilic anaerobic membrane reactor.

    PubMed

    Qiao, Wei; Takayanagi, Kazuyuki; Li, Qian; Shofie, Mohammad; Gao, Fang; Dong, Renjie; Li, Yu-You

    2016-12-01

    In this study, sulfate was employed as an external electron acceptor for enhancing the degradation of propionate in a thermophilic anaerobic membrane reactor (AnMBR). The organic loading rate (OLR) was increased gradually from the initial 3.9 kg-COD/m(3)d to the inhibiting OLR of 14.6 kg-COD/m(3)d. Feeding was stopped for 98 days but the process did not recover until 500 mg/L of sulfate was added into the AnMBR. After that, the enhanced propionate degradation was achieved up to an OLR of 15 kg-COD/m(3)d with a reduced sulfate addition of 300 mg/L. However, the thermodynamic calculation indicated that the syntrophic propionic acid degradation, coupled with methanogenesis, was unfavorable with a △G of +3 kJ/mol under the enhanced conditions. Conversely, the utilization of propionic acid by sulfate reduction bacterial (SRB) would be more favourable by having a much lower △G of -180 kJ/mol. The hydrogen conversion was presumed to go through the methanogenesis pathway according to the thermodynamic results. The mechanism of the propionic and hydrogen metabolism was supported as well by comparing the microbial communities with and without sulfate addition. As a result, the role of the sulfate enhancing propionic degradation can be concluded by combining the process performance, thermodynamic, and microbiology results. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    PubMed Central

    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

  2. Optimization of two-phase thermophilic anaerobic digestion of biowaste for hydrogen and methane production through reject water recirculation.

    PubMed

    Cavinato, C; Bolzonella, D; Fatone, F; Cecchi, F; Pavan, P

    2011-09-01

    The optimization of a two-phase thermophilic anaerobic process treating biowaste for hydrogen and methane production was carried out at pilot scale using two stirred reactors (CSTRs) and without any physical/chemical pre-treatment of inoculum. During the experiment the hydrogen production at low hydraulic retention time (3d) was tested, both with and without reject water recirculation and at two organic loading rate (16 and 21 kgTVS/m3 d). The better yields were obtained with recirculation where the pH reached an optimal value (5.5) thanks to the buffering capacity of the recycle stream. The specific gas production of the first reactor was 51 l/kgVS(fed) and H2 content in biogas 37%. The mixture of gas obtained from the two reactors met the standards for the biohythane mix only when lower loading rate were applied to the first reactor, with a composition of 6.7% H2, 40.1% CO2 and 52.3% CH4 the overall SGP being 0.78 m3/kgVS(fed).

  3. Caldimicrobium rimae gen. nov., sp. nov., an extremely thermophilic, facultatively lithoautotrophic, anaerobic bacterium from the Uzon Caldera, Kamchatka.

    PubMed

    Miroshnichenko, Margarita L; Lebedinsky, Alexander V; Chernyh, N A; Tourova, Tatyana P; Kolganova, Tatyana V; Spring, Stefan; Bonch-Osmolovskaya, Elizaveta A

    2009-05-01

    An extremely thermophilic, strictly anaerobic, facultatively chemolithoautotrophic bacterium designated strain DS(T) was isolated from Treshchinnyi Spring, one of the hottest springs of the Uzon Caldera (Kamchatka, Russia). Cells of the novel organism were Gram-negative rods, about 1.0-1.2 microm long and 0.5 microm wide. The temperature range for growth was 52-82 degrees C, with an optimum at 75 degrees C. Growth was observed at pH 6.8-7.4, and the optimum pH was 7.0-7.2. Strain DS(T) was able to grow lithoautotrophically with hydrogen in the presence of CO(2) as a carbon source and thiosulfate or elemental sulfur as an electron acceptor. It also grew well with ethanol, fumarate, succinate or malate in the presence of thiosulfate. Yeast extract was not required for growth and did not stimulate growth. The genomic DNA G+C content was 35.2 mol%. Phylogenetic analysis of the 16S rRNA gene sequence indicated that the novel organism was a member of the family Thermodesulfobacteriaceae. On the basis of phylogenetic and physiological considerations, it is proposed that strain DS(T) represents a new genus and species, Caldimicrobium rimae gen. nov., sp. nov. The type strain of Caldimicrobium rimae is DS(T) (=DSM 19393(T) =VKM B-2460(T)).

  4. Yearlong semi-continuous operation of thermophilic two-stage anaerobic digesters amended with biochar for enhanced biomethane production

    DOE PAGES

    Shen, Yanwen; Forrester, Sara; Koval, Jason; ...

    2017-05-29

    This study aimed to scale up an integrated waste-to-energy system for producing pipelinequality biomethane from shake flasks experiments to two-stage digester systems with semicontinuous operation. The yearlong operation was successfully conducted to compare the performance of thermophilic anaerobic digestion (AD) of sewage sludge amended with corn stover biochar (CSBC) and pine biochar (PBC) to the control under various conditions. Both CSBC and PBC promoted the substrate utilization, methane productivity, and process stability of AD, while CSBC showed superior potential. CSBC enhanced methane content in biogas (CH4%) and methane production rate (PCHmore » $$_4$$) by up to 25% and 37% respectively in comparison to the control, with maximum CH4% of 95% and CH4 yield of 0.34 L/g volatile solid (VS)-added being achieved at steady state. The biochar supplementation also led to a substantial increase of the macro- and micro-nutrients (P, K, Ca, Mg, Fe) by up to 33 times in the digestate, increasing its fertilizer value. Finally, microbial community structure and dynamics were also investigated and compared, and in particular, CSBC promoted the abundance of Clostridia and Methanosarcina. Collectively, this study proves that pyro-biochar as an effective additive material enhances AD performance with continuous operation and that CSBC shows greater potential.« less

  5. An extremely thermophilic anaerobic bacterium Caldicellulosiruptor sp. F32 exhibits distinctive properties in growth and xylanases during xylan hydrolysis.

    PubMed

    Ying, Yu; Meng, Dongdong; Chen, Xiaohua; Li, Fuli

    2013-08-15

    An anaerobic, extremely thermophilic, and cellulose- and xylan-degrading bacterium F32 was isolated from biocompost. Sequence analysis of the 16S rRNA gene of this strain showed that it was closely related to Caldicellulosiruptor saccharolyticus DSM 8903 (99.0% identity). Physiological and biochemical data also supported that identification of strain F32 as a Caldicellulosiruptor species. The proteins secreted by Caldicellulosiruptor sp. F32 grown on xylan showed a xylanase activity of 7.74U/mg, which was 2.5 times higher than that of C. saccharolyticus DSM 8903. Based on the genomic sequencing data, 2 xylanase genes, JX030400 and JX030401, were identified in Caldicellulosiruptor sp. F32. The xylanase encoded by JX030401 shared 97% identity with Csac_0696 of C. saccharolyticus DSM 8903, while that encoded by JX030400 shared 94% identity with Athe_0089 of C. bescii DSM 6725, which was not found in the genome of strain DSM 8903. Xylanse encoded by JX030400 had 9-fold higher specific activity than JX030401. Our results indicated that although the 2 strains shared high identity, the xylanase system in Caldicellulosiruptor sp. F32 was more efficient than that in C. saccharolyticus DSM 8903.

  6. Isolation and characterization of Keratinibaculum paraultunense gen. nov., sp. nov., a novel thermophilic, anaerobic bacterium with keratinolytic activity.

    PubMed

    Huang, Yan; Sun, Yingjie; Ma, Shichun; Chen, Lu; Zhang, Hui; Deng, Yu

    2013-08-01

    A novel thermophilic, anaerobic, keratinolytic bacterium designated KD-1 was isolated from grassy marshland. Strain KD-1 was a spore-forming rod with a Gram-positive type cell wall, but stained Gram-negative. The temperature, pH, and NaCl concentration range necessary for growth was 30-65 °C (optimum 55 °C), 6.0-10.5 (optimum 8.0-8.5), and 0-6% (optimum 0.2%) (w/v), respectively. Strain KD-1 possessed extracellular keratinase, and the optimum activity of the crude enzyme was pH 8.5 and 70 °C. The enzyme was identified as a thermostable serine-type protease. The strain was sensitive to rifampin, chloramphenicol, kanamycin, and tetracycline and was resistant to erythromycin, neomycin, penicillin, and streptomycin. The main cellular fatty acid was predominantly C15:0 iso (64%), and the G+C content was 28 mol%. Morphological and physiological characterization, together with phylogenetic analysis based on 16S rRNA gene sequencing identified KD-1 as a new species of a novel genus of Clostridiaceae with 95.3%, 93.8% 16S rRNA gene sequence similarity to Clostridium ultunense BS(T) (DSM 10521(T)) and Tepidimicrobium xylanilyticum PML14(T) (= JCM 15035(T)), respectively. We propose the name Keratinibaculum paraultunense gen. nov., sp. nov., with KD-1 (=JCM 18769(T) =DSM 26752(T)) as the type strain.

  7. Thermosipho affectus sp. nov., a thermophilic, anaerobic, cellulolytic bacterium isolated from a Mid-Atlantic Ridge hydrothermal vent.

    PubMed

    Podosokorskaya, O A; Kublanov, I V; Reysenbach, A-L; Kolganova, T V; Bonch-Osmolovskaya, E A

    2011-05-01

    A novel obligately anaerobic, extremely thermophilic, organotrophic bacterium, strain ik275mar(T), was isolated from a Mid-Atlantic Ridge deep-sea hydrothermal vent. Cells were rods surrounded by a sheath-like structure (toga), 0.4-0.9 µm in width and 1.2-6.0 µm in length. Strain ik275mar(T) grew at 37-75 °C, pH 5.6-8.2 and at NaCl concentrations of 10-55 g l(-1). Under optimum conditions (70 °C, pH 6.6, NaCl 20 g l(-1)), doubling time was 32 min. The isolate was able to ferment carbohydrates including starch, cellulose and cellulose derivatives. Acetate, H(2) and CO(2) were the main products of glucose fermentation. G+C content of DNA was 27 mol%. Phylogenetic analysis of 16S rRNA gene sequences showed that strain ik275mar(T) is a member of the genus Thermosipho. 16S rRNA gene sequence identity with the other species of the genus Thermosipho ranged from 93.7 to 94.5 %. Based on the phylogenetic analysis and physiological properties of the novel isolate, we propose a novel species, Thermosipho affectus sp. nov., with type strain ik275mar(T) ( = DSM 23112(T)  = VKM B-2574(T)).

  8. Mitigating ammonia inhibition of thermophilic anaerobic treatment of digested piggery wastewater: use of pH reduction, zeolite, biomass and humic acid.

    PubMed

    Ho, L; Ho, G

    2012-09-15

    High free ammonia released during anaerobic digestion of livestock wastes is widely known to inhibit methanogenic microorganisms and result in low methane production. This was encountered during our earlier thermophilic semi-continuously fed continuously-stirred tank reactor (CSTR) treatment of piggery wastewater. This study explored chemical and biological means to mitigate ammonia inhibition on thermophilic anaerobic treatment of piggery wastewater with the aim to increase organic volatile carbon reduction and methane production. A series of thermophilic anaerobic batch experiments were conducted on the digested piggery effluent to investigate the effects of pH reduction (pH 8.3 to 7.5, 7.0 and 6.5) and additions of biomass (10% v/v and 19% v/v anaerobic digested piggery biomass and aerobic-anaerobic digested municipal biomass), natural zeolite (10, 15 and 20 g/L) and humic acid (1, 5 and 10 g/L) on methane production at 55 °C for 9-11 days. Reduction of the wastewater pH from its initial pH of 8.3 to 6.5 produced the greatest stimulation of methane production (3.4 fold) coupled with reductions in free ammonia (38 fold) and total volatile fatty acids (58% TVFA), particularly acetate and propionate. Addition of 10-20 g/L zeolite to piggery wastewater with and without pH reduction to 6.5 further enhanced total VFA reduction and methane production over their respective controls, with 20 g/L zeolite producing the highest enhancement effect despite the ammonia-nitrogen concentrations of the treated wastewaters remaining high. Without pH reduction, zeolite concentration up to 20 g/L was required to achieve comparable methane enhancement as the pH-reduced wastewater at pH 6.5. Although biomass (10% v/v piggery and municipal wastes) and low humic acid (1 and 5 g/L) additions enhanced total VFA reduction and methane production, they elevated the residual effluent total COD concentrations over the control wastewaters (pH-unadjusted and pH-reduced) unlike zeolite

  9. Thermophilic, anaerobic co-digestion of microalgal biomass and cellulose for H2 production.

    PubMed

    Carver, Sarah M; Hulatt, Chris J; Thomas, David N; Tuovinen, Olli H

    2011-07-01

    Microalgal biomass has been a focus in the sustainable energy field, especially biodiesel production. The purpose of this study was to assess the feasibility of treating microalgal biomass and cellulose by anaerobic digestion for H2 production. A microbial consortium, TC60, known to degrade cellulose and other plant polymers, was enriched on a mixture of cellulose and green microalgal biomass of Dunaliella tertiolecta, a marine species, or Chlorella vulgaris, a freshwater species. After five enrichment steps at 60°C, hydrogen yields increased at least 10% under all conditions. Anaerobic digestion of D. tertiolecta and cellulose by TC60 produced 7.7 mmol H2/g volatile solids (VS) which were higher than the levels (2.9-4.2 mmol/g VS) obtained with cellulose and C. vulgaris biomass. Both microalgal slurries contained satellite prokaryotes. The C. vulgaris slurry, without TC60 inoculation, generated H2 levels on par with that of TC60 on cellulose alone. The biomass-fed anaerobic digestion resulted in large shifts in short chain fatty acid concentrations and increased ammonium levels. Growth and H2 production increased when TC60 was grown on a combination of D. tertiolecta and cellulose due to nutrients released from algal cells via lysis. The results indicated that satellite heterotrophs from C. vulgaris produced H2 but the Chlorella biomass was not substantially degraded by TC60. To date, this is the first study to examine H2 production by anaerobic digestion of microalgal biomass. The results indicate that H2 production is feasible but higher yields could be achieved by optimization of the bioprocess conditions including biomass pretreatment.

  10. Ethanol Production from Wet-Exploded Wheat Straw Hydrolysate by Thermophilic Anaerobic Bacterium Thermoanaerobacter BG1L1 in a Continuous Immobilized Reactor

    NASA Astrophysics Data System (ADS)

    Georgieva, Tania I.; Mikkelsen, Marie J.; Ahring, Birgitte K.

    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 70°C. Undetoxified wheat straw hydrolysate was used (3-12% dry matter), corresponding to sugar mixtures of glucose and xylose ranging from 12 to 41 g/1. The organism, thermophilic anaerobic bacterium Thermoanaerobacter BG1L1, exhibited significant resistance to high levels of acetic acid (up to 10 g/1) and other metabolic inhibitors present in the hydrolysate. Although the hydrolysate was not detoxified, ethanol yield in a range of 0.39-0.42 g/g was obtained. Overall, sugar efficiency to ethanol was 68-76%. The reactor was operated continuously for approximately 143 days, and no contamination was seen without the use of any agent for preventing bacterial infections. The tested microorganism has considerable potential to be a novel candidate for lignocellulose bioconversion into ethanol. The work reported here also demonstrates that the use of FBR configuration might be a viable approach for thermophilic anaerobic ethanol fermentation.

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

    PubMed

    Georgieva, Tania I; Mikkelsen, Marie J; Ahring, Birgitte K

    2008-03-01

    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 70 degrees C. 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 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 considerable potential to be a novel candidate for lignocellulose bioconversion into ethanol. The work reported here also demonstrates that the use of FBR configuration might be a viable approach for thermophilic anaerobic ethanol fermentation.

  12. 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.

    PubMed

    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 VSremoved, and 0.65 (65% CH4) and 0.73 (60.02% CH4) m(3) biogas/kg VSfed, 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.

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

    PubMed

    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.

  14. High Ethanol Titers from Cellulose by Using Metabolically Engineered Thermophilic, Anaerobic Microbes ▿ † ‡

    PubMed Central

    Argyros, D. Aaron; Tripathi, Shital A.; Barrett, Trisha F.; Rogers, Stephen R.; Feinberg, Lawrence F.; Olson, Daniel G.; Foden, Justine M.; Miller, Bethany B.; Lynd, Lee R.; Hogsett, David A.; Caiazza, Nicky C.

    2011-01-01

    This work describes novel genetic tools for use in Clostridium thermocellum that allow creation of unmarked mutations while using a replicating plasmid. The strategy employed counter-selections developed from the native C. thermocellum hpt gene and the Thermoanaerobacterium saccharolyticum tdk gene and was used to delete the genes for both lactate dehydrogenase (Ldh) and phosphotransacetylase (Pta). The Δldh Δpta mutant was evolved for 2,000 h, resulting in a stable strain with 40:1 ethanol selectivity and a 4.2-fold increase in ethanol yield over the wild-type strain. Ethanol production from cellulose was investigated with an engineered coculture of organic acid-deficient engineered strains of both C. thermocellum and T. saccharolyticum. Fermentation of 92 g/liter Avicel by this coculture resulted in 38 g/liter ethanol, with acetic and lactic acids below detection limits, in 146 h. These results demonstrate that ethanol production by thermophilic, cellulolytic microbes is amenable to substantial improvement by metabolic engineering. PMID:21965408

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

    PubMed

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

    2006-02-01

    biosolids are land-applied, require compliance with both bacterial limits. Additional work identified dewatering, cooling of biosolids after the dewatering centrifuges, and contamination as possible factors in the rise in density of fecal coliforms. These results provided the basis for the full conversion of HTP to the Los Angeles continuous-batch, thermophilic-anaerobic-digestion process. During later phases of testing, this process was demonstrated to produce fully disinfected biosolids at the farm for land application.

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

    PubMed

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

    2013-10-01

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

  17. Biohydrogen production in granular up-flow anaerobic sludge blanket (UASB) reactors with mixed cultures under hyper-thermophilic temperature (70 degrees C).

    PubMed

    Kotsopoulos, Thomas A; Zeng, Raymond J; Angelidaki, Irini

    2006-06-05

    Hyper-thermophilic hydrogen production without methane was demonstrated for the first time in granular up-flow anaerobic sludge blanket (UASB) system fed with glucose using mixed cultures. The maximum hydrogen yield in this study was 2.47 +/- 0.15 mol H2/mol glucose. This high yield has never been previously reported in mixed culture systems and it was likely due to more favorable thermodynamic conditions at hyper-thermophilic temperatures. Different start-up strategies (bromoethanosulfonate (BES) addition and flow recycle) were evaluated. BES addition during start-up prevented the establishment of methanogenic cultures in granules. Flow recycle was important to achieve higher hydrogen yield through enriching better hydrogen-producing organisms and reduced the start-up period as well. This study indicated UASB system was a promising system for hydrogen production.

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

    PubMed

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

    2015-04-01

    The Biohydrogen Potential (BHP) of six different types of waste biomass typical for the Campania Region (Italy) was investigated. Anaerobic sludge pre-treated with the specific methanogenic inhibitor sodium 2-bromoethanesulfonic acid (BESA) was used as seed inoculum. The BESA pre-treatment yielded the highest BHP in BHP tests carried out with pre-treated anaerobic sludge using potato and pumpkin waste as the substrates, in comparison with aeration or heat shock pre-treatment. The BHP tests carried out with different complex waste biomass showed average BHP values in a decreasing order from potato and pumpkin wastes (171.1 ± 7.3 ml H2/g VS) to buffalo manure (135.6 ± 4.1 ml H2/g VS), dried blood (slaughter house waste, 87.6 ± 4.1 ml H2/g VS), fennel waste (58.1 ± 29.8 ml H2/g VS), olive pomace (54.9 ± 5.4 ml H2/g VS) and olive mill wastewater (46.0 ± 15.6 ml H2/g VS). The digestate was analyzed for major soluble metabolites to elucidate the different biochemical pathways in the BHP tests. These showed the H2 was produced via mixed type fermentation pathways. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

    PubMed

    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 CODfed. 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 CODfed, 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.

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

    PubMed

    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 H2 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 H2, 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

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

    PubMed Central

    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 H2 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 H2, 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

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

    DOE PAGES

    Kublanov, Ilya V.; Sigalova, Olga M.; Gavrilov, Sergey N.; ...

    2017-02-20

    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 H2 during fermentation, and one is apparently bidirectional. The ability to reduce nitrate is determined by a nitrate reductase of the Nap family, whilemore » 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 H2, 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

  3. Caldicoprobacter guelmensis sp. nov., a thermophilic, anaerobic, xylanolytic bacterium isolated from a hot spring.

    PubMed

    Bouanane-Darenfed, Amel; Ben Hania, Wajdi; Hacene, Hocine; Cayol, Jean-Luc; Ollivier, Bernard; Fardeau, Marie-Laure

    2013-06-01

    A hyperthermophilic anaerobic bacterium, designated D2C22(T), was isolated from the hydrothermal hot spring of Guelma in north-east Algeria. The isolate was a Gram-stain-positive, non-sporulating, non-motile rod, appearing singly or in pairs (0.3-0.4 × 8.0-9.0 µm). Strain D2C22(T) grew anaerobically at 45-85 °C (optimum 65 °C), at pH 5-9 (optimum pH 6.8) and with 0-20 g NaCl l(-1). Strain D2C22(T) used glucose, galactose, lactose, fructose, ribose, xylose, arabinose, maltose, cellobiose, mannose, melibiose, sucrose, xylan and pyruvate (only in the presence of yeast extract or biotrypticase) as electron donors. The end products from glucose fermentation were acetate, lactate, CO2 and H2. Nitrate, nitrite, thiosulfate, elemental sulfur, sulfate and sulfite were not used as electron acceptors. The predominant cellular fatty acids were iso-C15:0 and iso-C17:0. The DNA G+C content was 41.6 mol%. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain D2C22(T) was most closely related to Caldicoprobacter oshimai JW/HY-331(T), Caldicoprobacter algeriensis TH7C1(T) and Acetomicrobium faecale DSM 20678(T) (95.5, 95.5 and 95.3% 16S rRNA gene sequence similarity, respectively). Based on phenotypic, phylogenetic and chemotaxonomic characteristics, strain D2C22(T) is proposed to be a representative of a novel species of the genus Caldicoprobacter within the order Clostridiales, for which the name Caldicoprobacter guelmensis sp. nov. is proposed. The type strain is D2C22(T) (=DSM 24605(T)=JCM 17646(T)).

  4. Methanosarcinaceae and Acetate-Oxidizing Pathways Dominate in High-Rate Thermophilic Anaerobic Digestion of Waste-Activated Sludge

    PubMed Central

    Ho, Dang P.; Jensen, Paul D.

    2013-01-01

    This study investigated the process of high-rate, high-temperature methanogenesis to enable very-high-volume loading during anaerobic digestion of waste-activated sludge. Reducing the hydraulic retention time (HRT) from 15 to 20 days in mesophilic digestion down to 3 days was achievable at a thermophilic temperature (55°C) with stable digester performance and methanogenic activity. A volatile solids (VS) destruction efficiency of 33 to 35% was achieved on waste-activated sludge, comparable to that obtained via mesophilic processes with low organic acid levels (<200 mg/liter chemical oxygen demand [COD]). Methane yield (VS basis) was 150 to 180 liters of CH4/kg of VSadded. According to 16S rRNA pyrotag sequencing and fluorescence in situ hybridization (FISH), the methanogenic community was dominated by members of the Methanosarcinaceae, which have a high level of metabolic capability, including acetoclastic and hydrogenotrophic methanogenesis. Loss of function at an HRT of 2 days was accompanied by a loss of the methanogens, according to pyrotag sequencing. The two acetate conversion pathways, namely, acetoclastic methanogenesis and syntrophic acetate oxidation, were quantified by stable carbon isotope ratio mass spectrometry. The results showed that the majority of methane was generated by nonacetoclastic pathways, both in the reactors and in off-line batch tests, confirming that syntrophic acetate oxidation is a key pathway at elevated temperatures. The proportion of methane due to acetate cleavage increased later in the batch, and it is likely that stable oxidation in the continuous reactor was maintained by application of the consistently low retention time. PMID:23956388

  5. Tepidibacillus fermentans gen. nov., sp. nov.: a moderately thermophilic anaerobic and microaerophilic bacterium from an underground gas storage.

    PubMed

    Slobodkina, G B; Panteleeva, A N; Kostrikina, N A; Kopitsyn, D S; Bonch-Osmolovskaya, E A; Slobodkin, A I

    2013-09-01

    A novel moderately thermophilic bacterium, strain STGH(T), was isolated from Severo-Stavropolskoye underground gas storage (Russia). Cells of strain STGH(T) were spore-forming motile straight rods 0.3 μm in diameter and 2.0-4.0 μm in length having a Gram-positive cell wall structure. The temperature range for growth was 36-65 °C, with an optimum at 50-52 °C. The pH range for growth was 5.5-8.0, with an optimum at pH 7.0-7.5. Growth of strain STGH(T) was observed at NaCl concentrations ranging from 0 to 4.0 % (w/v) with an optimum at 1.0 % (w/v). Strain STGH(T) grew anaerobically by reduction of nitrate, thiosulfate, S(0) and AQDS using a number of complex proteinaceous compounds, organic acids and carbohydrates as electron donors. Nitrate was reduced to nitrite; thiosulfate and sulfur were reduced to sulfide. It also was able to ferment pyruvate, glucose, fructose, and maltose. The strain STGH(T) did not grow under aerobic conditions during incubation with atmospheric concentration of oxygen but was able to microaerobic growth (up to 10 % of oxygen in gas phase). The G+C content of DNA of strain STGH(T) was 34.8 mol%. 16S rRNA gene sequence analysis revealed that the isolated organism belongs to the class Bacilli. We propose to assign strain STGH(T) to a new species of a novel genus Tepidibacillus fermentans gen. nov., sp.nov. The type strain is STGH(T) (=DSM 23802(T), =VKM B-2671(T)).

  6. Deferribacter abyssi sp. nov., an anaerobic thermophile from deep-sea hydrothermal vents of the Mid-Atlantic Ridge.

    PubMed

    Miroshnichenko, M L; Slobodkin, A I; Kostrikina, N A; L'Haridon, S; Nercessian, O; Spring, S; Stackebrandt, E; Bonch-Osmolovskaya, E A; Jeanthon, C

    2003-09-01

    Two strains of thermophilic, anaerobic, chemolithoautotrophic bacteria, designated JR(T) and DR, were isolated from hydrothermal samples collected on the Mid-Atlantic Ridge from the Rainbow (36 degrees 16' N, 33 degrees 54' W) and Menez Gwen (37 degrees 50' N, 31 degrees 50' W) vent fields, respectively. Cells of both isolates were short, straight- to vibrio-shaped, motile rods with one polar flagellum, and were Gram-negative and non-sporulating. Strain JR(T) was characterized in detail. It was found to grow optimally at pH 6.5-6.7, at 60 degrees C and in the presence of 30 g NaCl l(-1). Strain JR(T) could use molecular hydrogen, acetate, succinate, pyruvate and proteinaceous compounds as electron donors, and elemental sulfur, nitrate or Fe(III) as electron acceptors. No fermentation of organic substrates occurred. The G+C content of the DNA of strain JR(T) was 30.8 mol%. Strain DR (=DSM 14927) possessed the same morphology and pH, temperature and salinity optima and ranges, and used the same electron acceptors as strain JR(T). On the basis of their 16S rDNA sequences (1517 nucleotides), strains JR(T) and DR were identical and distantly related to Deferribacter thermophilus and Deferribacter desulfuricans (95.3 and 95.2 % sequence similarity, respectively). Based on their phenotypic and phylogenetic characteristics, it is proposed that both strains are members of a new species of the genus Deferribacter, for which the name Deferribacter abyssi (type strain JR(T)=DSM 14873(T)=JCM 11955(T)) is proposed.

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

    PubMed

    Angelidaki, I; Cui, J; Chen, X; Kaparaju, P

    2006-08-01

    Three operational strategies to reduce inhibition due to ammonia during thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste (SS-OFMSW) rich in proteins were investigated. Feed was prepared by diluting SS-OFMSW (ratio of 1:4) with tap water or reactor process water with or without stripping ammonia. Three continuously stirred tank reactors were operated at 55 degrees C with 11.4 gVS d(-1) loading rate and 15 d retention time. Total ammonia nitrogen (TAN) level in the reactor fed with recirculated water alone was spiked to 3.5 and 5.5 g-N l(-1) through ammonium bicarbonate additions. Dilution of SS-OFMSW with fresh water showed a stable performance with volatile fatty acids of < 1g l(-1) and methane yield of 0.40 m3 kg(-1) volatile solids (VS). Use of recirculated process water after stripping ammonia showed even better performance with a methane yield of 0.43 m3 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 ammonia would not only evade potential inhibition due to ammonia but could avoid the use of fresh water for dilution of high solids protein-rich SS-OFMSW.

  8. Marinitoga arctica sp. nov., a thermophilic, anaerobic heterotroph isolated from a Mid-Ocean Ridge vent field.

    PubMed

    Steinsbu, Bjørn O; Røyseth, Victoria; Thorseth, Ingunn H; Steen, Ida H

    2016-12-01

    A thermophilic, anaerobic, heterotrophic bacterium, designated 2PyrY55-1T, was isolated from the wall of an active hydrothermal white-smoker chimney in the Soria Moria vent field (71° N) at the Mohns Ridge in the Norwegian-Greenland Sea. Cells of the strain were Gram-negative, motile rods that possessed a polar flagellum and a sheath-like outer structure ('toga'). Growth was observed at 45-70 °C (optimum 65 °C), at pH 5.0-7.5 (optimum pH 5.5) and in 1.5-5.5 % (w/v) NaCl (optimum 2.5 %). The strain grew on pyruvate, complex proteinaceous substrates and various sugars. Cystine and elemental sulfur were used as electron acceptors, and sulfide was then produced. The G+C content of the genomic DNA was 27 mol% (Tm method). Cellular fatty acids included C16 : 0, C14 : 0, C16 : 1ω7c and/or iso-C15 : 0 2-OH, C16 : 1ω9c, C18 : 1ω9c, C18 : 0, C18 : 1ω7c and C12 : 0. Phylogenetic analyses of the 16S rRNA gene showed that the strain belonged to the genus Marinitoga in the family Petrotogaceae. Based on the phylogenetic and chemotaxonomic data, strain 2PyrY55-1T (=DSM 29778T=JCM 30566T) is the type strain of a novel species of the genus Marinitoga, for which the name Marinitoga arctica sp. nov. is proposed.

  9. Thermoterrabacterium ferrireducens gen. nov., sp. nov., a thermophilic anaerobic dissimilatory Fe(III)-reducing bacterium from a continental hot spring

    SciTech Connect

    Slobodkin, A.; Wiegel, J.; Reysenbach, A.L.

    1997-04-01

    A strain of a thermophilic, anaerobic, dissimilatory, Fe(III)-reducing bacterium, Thermoterrabacterium ferrireducens gen. nov., sp. nov. (type strain JW/AS-Y7{sup T}; DSM 11255), was isolated from hot springs in Yellowstone National Park and New Zealand. The gram-positive-staining cells occurred singly or in pairs as straight to slightly curved rods, 0.3 to 0.4 by 1.6 to 2.7 {mu}m, with rounded ends and exhibited a tumbling motility. Spores were not observed. The temperature range for growth was 50 to 74{degrees}C with an optimum at 65{degrees}C. The pH range for growth at 65{degrees}C was from 5.5 to 7.6, with an optimum at 6.0 to 6.2. The organism coupled the oxidation of glycerol to reduction of amorphous Fe(III) oxide or Fe(III) citrate as an electron acceptor. In the presence as well as in the absence of Fe(III) and in the presence of CO{sub 2}, glycerol was metabolized by incomplete oxidation to acetate as the only organic metabolic product; no H{sub 2} was produced during growth. The organism utilized glycerol, lactate, 1,2-propanediol, glycerate, pyruvate, glucose, fructose, mannose, and yeast extract as substrates. In the presence of Fe(III) the bacterium utilized molecular hydrogen. The organism reduced 9,10-anthraquinone-2,6-disulfonic acid, fumarate (to succinate), and thiosulfate (to elemental sulfur) but did not reduce MnO{sub 2}, nitrate, sulfate, sulfite, or elemental sulfur. The G+C content of the DNA was 41 mol% (as determined by high-performance liquid chromatography). The 16S ribosomal DNA sequence analysis placed the isolated strain as a member of a new genus within the gram-type positive Bacillus-Clostridium subphylum.

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

    PubMed

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

    2008-11-01

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

  11. Caloranaerobacter ferrireducens sp. nov., an anaerobic, thermophilic, iron (III)-reducing bacterium isolated from deep-sea hydrothermal sulfide deposits.

    PubMed

    Zeng, Xiang; Zhang, Zhao; Li, Xi; Jebbar, Mohamed; Alain, Karine; Shao, Zongze

    2015-06-01

    A thermophilic, anaerobic, iron-reducing bacterium (strain DY22619T) was isolated from a sulfide sample collected from an East Pacific Ocean hydrothermal field at a depth of 2901 m. Cells were Gram-stain-negative, motile rods (2-10 µm in length, 0.5 µm in width) with multiple peritrichous flagella. The strain grew at 40-70 °C inclusive (optimum 60 °C), at pH 4.5-8.5 inclusive (optimum pH 7.0) and with sea salts concentrations of 1-10 % (w/v) (optimum 3 % sea salts) and NaCl concentrations of 1.5-5.0 % (w/v) (optimum 2.5 % NaCl). Under optimal growth conditions, the generation time was around 55 min. The isolate was an obligate chemoorganoheterotroph, utilizing complex organic compounds, amino acids, carbohydrates and organic acids including peptone, tryptone, beef extract, yeast extract, alanine, glutamate, methionine, threonine, fructose, mannose, galactose, glucose, palatinose, rhamnose, turanose, gentiobiose, xylose, sorbose, pyruvate, tartaric acid, α-ketobutyric acid, α-ketovaleric acid, galacturonic acid and glucosaminic acid. Strain DY22619T was strictly anaerobic and facultatively dependent on various forms of Fe(III) as an electron acceptor: insoluble forms and soluble forms. It did not reduce sulfite, sulfate, thiosulfate or nitrate. The genomic DNA G+C content was 29.0 mol%. Phylogenetic 16S rRNA gene sequence analyses revealed that the closest relative of strain DY22619T was Caloranaerobacter azorensis MV1087T, sharing 97.41 % 16S rRNA gene sequence similarity. On the basis of physiological distinctness and phylogenetic distance, the isolate is considered to represent a novel species of the genus Caloranaerobacter, for which the name Caloranaerobacterhttp://dx.doi.org/10.1601/nm.4081ferrireducens sp. nov. is proposed. The type strain is DY22619T ( = JCM 19467T = DSM 27799T = MCCC1A06455T).

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

    PubMed

    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.

  13. Comprehensive review and compilation of pretreatments for mesophilic and thermophilic anaerobic digestion.

    PubMed

    Bordeleau, É L; Droste, R L

    2011-01-01

    Organic matter hydrolysis prior to anaerobic digestion has been shown to improve biogas production (30-50%) and reduce solids (20-60%) by ultrasound, chemical, conventional heating, and microwave pretreatments. Numerous studies have been performed to determine the extent of digestion improvement but few focus on financial feasibility of these processes. A comprehensive model was created using Microsoft Excel and its Visual Basic Assistant to evaluate pretreatment permutations for conventional wastewater treatment plants. The four above-mentioned processes were evaluated for energetic and financial demands. Well-established energy equations and wastewater characteristics, both average and high, were used. Average and high flows were 460 and 750×10(3) m3/d, respectively. Net costs per influent flow for ultrasound, chemical, conventional heating, and microwave were 0.0166, 0.0217, 0.0124, 0.0119 $/m3 and 0.0264, 0.0357, 0.0187, and 0.0162 $/m3 for average and high conditions, respectively. The average cost increase from results excluding pretreatment use for all processes was 0.003 and 0.0055 $/m3 for average and high conditions, respectively. No matter the permutation, pretreatments requiring more energy to achieve required hydrolysis levels were costlier. If energetic recoveries are substantial, dewaterability is positively affected, and solids meet environmental constraints to be handled and disposed at lower costs, pretreatments can be viable.

  14. Using thermophilic anaerobic digestate effluent to replace freshwater for bioethanol production.

    PubMed

    Gao, Tiejun; Li, Xiaomei

    2011-01-01

    The possibility of using anaerobic digestate effluent (ADE) to replace freshwater and nutrients for bioethanol production was explored. The ethanol concentration yielded from ADE and post-centrifuged ADE supernatant was 79.60±1.75 g/L and 78.33±1.66 g/L, respectively, with a 24% dry mass (DM) of soft wheat. Ethanol production was enhanced in ADE by as much as 18% in comparison to the production in freshwater (66.61±0.28 g/L, p<0.01). Without yeast nutrients, ADE fermentation yielded an ethanol concentration of 81.10±2.87 g/L, which was significantly higher than that in freshwater fermentation (59.67±1.79 g/L). Analysis showed that ADE contained rich nitrogen, proteins and minerals. After one-step distillation, the ethanol concentration attained was 700.05±46.20 g/L in ADE as compared to 622.79±32.22 g/L in freshwater (p<0.05).

  15. Thermotalea metallivorans gen. nov., sp. nov., a thermophilic, anaerobic bacterium from the Great Artesian Basin of Australia aquifer.

    PubMed

    Ogg, Christopher D; Patel, Bharat K C

    2009-05-01

    A strictly anaerobic, thermophilic bacterium, designated strain B2-1(T), was isolated from microbial mats colonizing a runoff channel formed by free-flowing thermal water from a Great Artesian Basin, Australia, bore well (registered number 17263). The cells of strain B2-1(T) were slightly curved rods (3.0-3.5 x 0.6-0.7 microm) which stained Gram-negative. The strain grew optimally in tryptone-yeast extract-glucose medium at 50 degrees C (temperature growth range 30-55 degrees C) and a pH of 8 (pH growth range 6.5-9). Strain B2-1(T) grew poorly on yeast extract (0.2 %) and/or tryptone (0.2 %), which were obligately required for growth on other energy sources, including a range of other carbohydrates and organic acids, but not amino acids. The end-products of glucose fermentation were ethanol and acetate. In the presence of 0.2 % yeast extract, iron(III), manganese(IV) and elemental sulfur were reduced but sulfate, thiosulfate, sulfite, nitrate and nitrite were not reduced. Growth was inhibited by chloramphenicol, streptomycin, tetracycline, penicillin, ampicillin, sodium azide and by NaCl concentrations greater than 4 % (w/v). The DNA G+C content was 48+/-1 mol% as determined by the thermal denaturation method. 16S rRNA gene sequence analysis indicated that strain B2-1(T) was a member of the family Clostridiaceae, class Clostridia, phylum Firmicutes and was most closely related to Geosporobacter subterraneus DSM 17957(T) (89.9 % similarity). On the basis of 16S rRNA gene sequence comparisons and physiological characteristics, strain B2-1(T) is considered to represent a novel species of a new genus, for which the name Thermotalea metallivorans gen. nov., sp. nov. is proposed. The type strain is B2-1(T) (=KCTC 5625(T)=JCM 15105(T)=DSM 21119(T)).

  16. Methanogenesis in a Thermophilic (58°C) Anaerobic Digestor: Methanothrix sp. as an Important Aceticlastic Methanogen

    PubMed Central

    Zinder, S. H.; Cardwell, S.C.; Anguish, T.; Lee, M.; Koch, M.

    1984-01-01

    Aceticlastic methanogens and other microbial groups were enumerated in a 58°C laboratory-scale (3 liter) anaerobic digestor which was fed air-classified municipal refuse, a lignocellulosic waste (loading rate = 1.8 to 2.7 g of volatile solids per liter per day; retention time = 10 days). Two weeks after start-up, Methanosarcina sp. was present in high numbers (105 to 106 CFU/ml) and autofluorescent Methanosarcina-like clumps were abundant in sludge examined by using epifluorescence microscopy. After about 4 months of digestor operation, numbers of Methanosarcina sp. dropped 2 to 3 orders of magnitude and large numbers (most probable number = 106 to 107/ml) of a thermophilic aceticlastic methanogen morphologically resembing Methanothrix sp. were found. Methanothrix sp. had apparently displaced Methanosarcina sp. as the dominant aceticlastic methanogen in the digestor. During the period when Methanothrix sp. was apparently dominant, acetate concentrations varied between 0.3 and 1.5 μmol/ml during the daily feeding cycle, and acetate was the precursor of 63 to 66% of the methane produced during peak digestor methanogenesis. The apparent Km value obtained for methanogenesis from acetate, 0.3 μmol/ml, indicated that the aceticlastic methanogens were nearly saturated for substrate during most of the digestor cycle. CO2-reducing methanogens were capable of methanogenesis at rates more than 12 times greater than those usually found in the digestor. Added propionate (4.5 μmol/ml) was metabolized slowly by the digestor populations and slightly inhibited methanogenesis. Added n-butyrate, isobutyrate, or n-valerate (4.5 μmol/ml each) were broken down within 24 h. Isobutyrate was oxidized to acetate, a novel reaction possibly involving isomerization to n-butyrate. The rapid growth rate and versatile metabolism of Methanosarcina sp. make it a likely organism to be involved in start-up, whereas the low Km value of Methanothrix sp. for acetate may cause it to be favored in

  17. Anoxybacter fermentans gen. nov., sp. nov., a piezophilic, thermophilic, anaerobic, fermentative bacterium isolated from a deep-sea hydrothermal vent.

    PubMed

    Zeng, Xiang; Zhang, Zhao; Li, Xi; Zhang, Xiaobo; Cao, Junwei; Jebbar, Mohamed; Alain, Karine; Shao, Zongze

    2015-02-01

    A novel piezophilic, thermophilic, anaerobic, fermentative bacterial strain, designated strain DY22613(T), was isolated from a deep-sea hydrothermal sulfide deposit at the East Pacific Rise (GPS position: 102.6° W 3.1° S). Cells of strain DY22613(T) were long, motile rods (10 to 20 µm in length and 0.5 µm in width) with peritrichous flagella and were Gram-stain-negative. Growth was recorded at 44-72 °C (optimum 60-62 °C) and at hydrostatic pressures of 0.1-55 MPa (optimum 20 MPa). The pH range for growth was from pH 5.0 to 9.0 with an optimum at pH 7.0. Growth was observed in the presence of 1 to 8 % (w/v) sea salts and 0.65 to 5.2 % (w/v) NaCl, with optimum salt concentrations at 3.5 % for sea salts and at 2.3 % for NaCl. Under optimal growth conditions, the shortest generation time observed was 27 min (60 °C, 20 MPa). Strain DY22613(T) was heterotrophic, able to utilize complex organic compounds, amino acids, sugars and organic acids including peptone, tryptone, beef extract, yeast extract, alanine, glutamine, methionine, phenylalanine, serine, threonine, fructose, fucose, galactose, gentiobiose, glucose, mannose, melibiose, palatinose, rhamnose, turanose, pyruvate, lactic acid, methyl ester, erythritol, galacturonic acid and glucosaminic acid. Strain DY22613(T) was able to reduce Fe(III) compounds, including Fe(III) oxyhydroxide (pH 7.0), amorphous iron(III) oxide (pH 9.0), goethite (α-FeOOH, pH 12.0), Fe(III) citrate and elementary sulfur. Products of fermentation were butyrate, acetate and hydrogen. Main cellular fatty acids were iso-C15 : 0, iso-C14 : 0 3-OH and C14 : 0. The genomic DNA G+C content of strain DY22613(T) was 36.7 mol%. Based on 16S rRNA gene sequence analysis, the strain forms a novel lineage within the class Clostridia and clusters with the order Haloanaerobiales (86.92 % 16S rRNA gene sequence similarity). The phylogenetic data suggest that the lineage represents at least a novel genus and species, for which the name Anoxybacter

  18. Characterization of Melioribacter roseus gen. nov., sp. nov., a novel facultatively anaerobic thermophilic cellulolytic bacterium from the class Ignavibacteria, and a proposal of a novel bacterial phylum Ignavibacteriae.

    PubMed

    Podosokorskaya, Olga A; Kadnikov, Vitaly V; Gavrilov, Sergey N; Mardanov, Andrey V; Merkel, Alexander Y; Karnachuk, Olga V; Ravin, Nikolay V; Bonch-Osmolovskaya, Elizaveta A; Kublanov, Ilya V

    2013-06-01

    A novel moderately thermophilic, facultatively anaerobic chemoorganotrophic bacterium strain P3M-2(T) was isolated from a microbial mat developing on the wooden surface of a chute under the flow of hot water (46°C) coming out of a 2775-m-deep oil exploration well (Tomsk region, Russia). Strain P3M-2(T) is a moderate thermophile and facultative anaerobe growing on mono-, di- or polysaccharides by aerobic respiration, fermentation or by reducing diverse electron acceptors [nitrite, Fe(III), As(V)]. Its closest cultivated relative (90.8% rRNA gene sequence identity) is Ignavibacterium album, the only chemoorganotrophic member of the phylum Chlorobi. New genus and species Melioribacter roseus are proposed for isolate P3M-2(T) . Together with I. album, the new organism represents the class Ignavibacteria assigned to the phylum Chlorobi. The revealed group includes a variety of uncultured environmental clones, the 16S rRNA gene sequences of some of which have been previously attributed to the candidate division ZB1. Phylogenetic analysis of M. roseus and I. album based on their 23S rRNA and RecA sequences confirmed that these two organisms could represent an even deeper, phylum-level lineage. Hence, we propose a new phylum Ignavibacteriae within the Bacteroidetes-Chlorobi group with a sole class Ignavibacteria, two families Ignavibacteriaceae and Melioribacteraceae and two species I. album and M. roseus. This proposal correlates with chemotaxonomic data and phenotypic differences of both organisms from other cultured representatives of Chlorobi. The most essential differences, supported by the analyses of complete genomes of both organisms, are motility, facultatively anaerobic and obligately organotrophic mode of life, the absence of chlorosomes and the apparent inability to grow phototrophically.

  19. In Situ Expression of Acidic and Thermophilic Carbohydrate Active Enzymes by Filamentous Fungi (JGI Seventh Annual User Meeting 2012: Genomics of Energy and Environment)

    ScienceCinema

    Mosier, Annika [Stanford University

    2016-07-12

    Annika Mosier, graduate student from Stanford University presents a talk titled "In Situ Expression of Acidic and Thermophilic Carbohydrate Active Enzymes by Filamentous Fungi" at the JGI User 7th Annual Genomics of Energy & Environment Meeting on March 22, 2012 in Walnut Creek, Calif

  20. In Situ Expression of Acidic and Thermophilic Carbohydrate Active Enzymes by Filamentous Fungi (JGI Seventh Annual User Meeting 2012: Genomics of Energy and Environment)

    SciTech Connect

    Mosier, Annika

    2012-03-22

    Annika Mosier, graduate student from Stanford University presents a talk titled "In Situ Expression of Acidic and Thermophilic Carbohydrate Active Enzymes by Filamentous Fungi" at the JGI User 7th Annual Genomics of Energy & Environment Meeting on March 22, 2012 in Walnut Creek, Calif

  1. Removal of organics and nutrients from food wastewater using combined thermophilic two-phase anaerobic digestion and shortcut biological nitrogen removal.

    PubMed

    Cui, Fenghao; Lee, Seungho; Kim, Moonil

    2011-10-15

    A process combining pilot-scale two-phase anaerobic digestion and shortcut biological nitrogen removal (SBNR) was developed to treat organics and nutrients (nitrogen and phosphorus) from food wastewater. The thermophilic two-phase anaerobic digestion process was investigated without adjusting the pH of the wastewater for the pre-acidification process. The digested food wastewater was treated using the SBNR process without supplemental carbon sources or alkalinity. Under these circumstances, the combined system was able to remove about 99% of COD, 88% of TN, and 97% of TP. However, considerable amounts of nutrients were removed due to chemical precipitation processes between the anaerobic digestion and SBNR. The average TN removal efficiency of the SBNR process was about 74% at very low C/N (TCOD/TN) ratio of 2. The SBNR process removed about 39% of TP from the digested food wastewater. Conclusively, application of the combined system improved organic removal efficiency while producing valuable energy (biogas), removed nitrogen at a low C/N ratio, and conserved additional resources (carbon and alkalinity). Copyright © 2011 Elsevier Ltd. All rights reserved.

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

    PubMed

    Ogg, Christopher D; Patel, Bharat K C

    2009-05-01

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

  3. 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

    PubMed Central

    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

  4. 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.

    PubMed

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

    2014-09-01

    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.

  5. Sequential batch thermophilic solid-state anaerobic digestion of lignocellulosic biomass via recirculating digestate as inoculum - Part II: Microbial diversity and succession.

    PubMed

    Lin, Long; Yu, Zhongtang; Li, Yebo

    2017-10-01

    This study aimed to investigate the effect of recirculation of digestate as inoculum on the microbial communities in thermophilic solid-state anaerobic digestion (SS-AD) of yard trimmings. The SS-AD consisted of 4 consecutive runs (30days/run), with digestate from the previous run being used as the inoculum of the subsequent run. Bacterial and archaeal communities (day 0, 4, 8, 12, 20, and 30) were examined using Illumina sequencing of 16S rRNA genes. The results revealed substantial microbial succession toward increased diversity until run 3. The proportions of Firmicutes that contained cellulolytic bacteria doubled, which might explain the concomitantly increased cellulose degradation and volatile fatty acids (VFAs). Clostridia and Thermotogae appeared to correlate with VFAs. The VFA accumulation likely induced dynamic shifts of methanogens, particularly to hydrogenotrophic Methanothermobacter, implying that non-acetoclastic oxidative pathway dominated during the steady-state thermophilic SS-AD. This study suggested that recirculating SS-AD digestate might be an effective way for inoculation. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    PubMed

    Chaikasem, Supawat; Abeynayaka, Amila; Visvanathan, Chettiyappan

    2014-09-01

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

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

    PubMed

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

    2017-08-21

    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.

  8. Desulfotomaculum peckii sp. nov., a moderately thermophilic member of the genus Desulfotomaculum, isolated from an upflow anaerobic filter treating abattoir wastewaters.

    PubMed

    Jabari, Linda; Gannoun, Hana; Cayol, Jean-Luc; Hamdi, Moktar; Ollivier, Bernard; Fauque, Guy; Fardeau, Marie-Laure

    2013-06-01

    A novel anaerobic thermophilic sulfate-reducing bacterium designated strain LINDBHT1(T) was isolated from an anaerobic digester treating abattoir wastewaters in Tunisia. Strain LINDBHT1(T) grew at temperatures between 50 and 65 °C (optimum 55-60 °C), and at pH between 5.9 and 9.2 (optimum pH 6.0-6.8). Strain LINDBHT1(T) required salt for growth (1-40 g NaCl l(-1)), with an optimum of 20-30 g l(-1). In the presence of sulfate as terminal electron acceptor, strain LINDBHT1(T) used H2/CO2, propanol, butanol and ethanol as carbon and energy sources but fumarate, formate, lactate and pyruvate were not utilized. Butanol was converted to butyrate, while propanol and ethanol were oxidized to propionate and acetate, respectively. Sulfate, sulfite and thiosulfate were utilized as terminal electron acceptors but elemental sulfur, iron (III), fumarate, nitrate and nitrite were not used. The G+C content of the genomic DNA was 44.4 mol%. Phylogenetic analysis of the small-subunit rRNA gene sequence indicated that strain LINDBHT1(T) was affiliated to the genus Desulfotomaculum with the type strains of Desulfotomaculum halophilum and Desulfotomaculum alkaliphilum as its closest phylogenetic relatives (about 89% similarity). This strain represents a novel species of the genus Desulfotomaculum, Desulfotomaculum peckii sp. nov.; the type strain is LINDBHT1(T) (=DSM 23769(T)=JCM 17209(T)).

  9. Thermophilic anaerobic biodegradation of (/sup 14/C)lignin, (/sup 14/C)cellulose, and (/sup 14/C)lignocellulose preparations

    SciTech Connect

    Benner, R.; Hodson, R.E.

    1985-10-01

    Thermophilic (55/sup 0/C) anaerobic enrichment cultures were incubated with (/sup 14/C-lignin)lignocellulose, (/sup 14/C- polysaccharide)lignocellulose, and kraft (/sup 14/C)lignin prepared from slash pine, Pinus elliotti, and /sup 14/C-labeled preparations of synthetic lignin and purified cellulose. Significant but low percentages (2 to 4%) of synthetic and natural pine lignin were recovered as labeled methane and carbon dioxide during 60-day incubations, whereas much greater percentages (13 to 23%) of kraft lignin were recovered as gaseous end products. Percentages of label recovered from lignin-labeled substrates as dissolved degradation products were approximately equal to percentages recovered as gaseous end products. High-pressure liquid chromatographic analyses of CuO oxidation products of sound and degraded pine lignin indicated that no substantial chemical modifications of the remaining lignin polymer, such as demethoxylation and dearomatization, occurred during biodegradation. The polysaccharide components of pine lignocellulose and purified cellulose were relatively rapidly mineralized to methane and carbon dioxide; 31% to 37% of the pine polysaccharides and 56% to 63% of the purified cellulose were recovered as labeled gaseous end products. An additional 10% to 20% of the polysaccharide substrates was recovered as dissolved degradation products. Overall, these results indicate that elevated temperatures can greatly enhance rates of anaerobic degradation of lignin and lignified substrates to methane and low-molecular-weight aromatic compounds.

  10. Anaerobic

    MedlinePlus

    ... more prolonged exercise like walking or jogging. Anaerobic reactions are faster. We need them during shorter, more intense activities like sprinting. Anaerobic exercise leads to a buildup of lactic acid in our tissues. We need oxygen to remove ...

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

    PubMed

    Nielsen, H B; Mladenovska, Z; Westermann, P; Ahring, B K

    2004-05-05

    A two-stage 68 degrees C/55 degrees C 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 68 degrees C for periods of 36, 108, and 168 h, and subsequently digested at 55 degrees C. In a lab-scale experiment, the performance of a two-stage reactor system, consisting of a digester operating at 68 degrees C with a hydraulic retention time (HRT) of 3 days, connected to a 55 degrees C reactor with 12-day HRT, was compared with a conventional single-stage reactor running at 55 degrees C 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 68 degrees C reactor generated 7% to 9% of the total amount of methane of the two-stage system and maintained a volatile fatty acids (VFA) concentration of 4.0 to 4.4 g acetate per liter. Population size and activity of aceticlastic methanogens, syntrophic bacteria, and hydrolytic/fermentative bacteria were significantly lower in the 68 degrees C reactor than in the 55 degrees C reactors. The density levels of methanogens utilizing H2/CO2 or formate were, however, in the same range for all reactors, although the degradation of these substrates was significantly lower in the 68 degrees C reactor than in the 55 degrees C reactors. Temporal temperature gradient electrophoresis profiles (TTGE) of the 68 degrees C reactor demonstrated a stable bacterial community along with a less divergent community of archaeal species.

  12. Reduced temperature hydrolysis at 134 °C before thermophilic anaerobic digestion of waste activated sludge at increasing organic load.

    PubMed

    Gianico, A; Braguglia, C M; Cesarini, R; Mininni, G

    2013-09-01

    The performance of thermophilic digestion of waste activated sludge, either untreated or thermal pretreated, was evaluated through semi-continuous tests carried out at organic loading rates in the range of 1-3.7 kg VS/m(3)d. Although the thermal pretreatment at T=134 °C proved to be effective in solubilizing organic matter, no significant gain in organics degradation was observed. However, the digestion of pretreated sludge showed significant soluble COD removal (more than 55%) whereas no removal occurred in control reactors. The lower the initial sludge biodegradability, the higher the efficiency of thermal pretreated digestion was observed, in particular as regards higher biogas and methane production rates with respect to the parallel untreated sludge digestion. Heat balance of the combined thermal hydrolysis/thermophilic digestion process, applied on full-scale scenarios, showed positive values for direct combustion of methane. In case of combined heat and power generation, attractive electric energy recoveries were obtained, with a positive heat balance at high load.

  13. Thermophilic and cellulolytic consortium isolated from composting plants improves anaerobic digestion of cellulosic biomass: Toward a microbial resource management approach.

    PubMed

    Kinet, R; Destain, J; Hiligsmann, S; Thonart, P; Delhalle, L; Taminiau, B; Daube, G; Delvigne, F

    2015-01-01

    A cellulolytic consortium was isolated from a composting plant in order to boost the initial hydrolysis step encountered in anaerobic digestion. Improvement of the cellulose degradation, as well as biogas production, was observed for the cultures inoculated with the exogenous consortium. Metagenomics analyses pointed out a weak richness (related to the number of OTUs) of the exogenous consortium induced by the selective pressure (cellulose as sole carbon source) met during the initial isolation steps. Main microbial strains determined were strictly anaerobic and belong to the Clostridia class. During cellulose anaerobic degradation, pH drop induced a strong modification of the microbial population. Despite the fact that richness and evenness were very weak, the exogenous consortium was able to adapt and to maintain the cellulolytic degradation potential. This important result point out the fact that simplified microbial communities could be used in order to increase the robustness of mixed cultures involved in environmental biotechnology.

  14. Effects of selected thermophilic microorganisms on crude oils at elevated temperatures and pressures. 1991 annual report

    SciTech Connect

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

    1993-10-01

    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. In this laboratory systematic studies are being conducted which deal 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 is being paid to heavy crude oils such as Boscan and Cerro Negro (Venezuela), Monterey (California) and those from Alabama and Arkansas. Current studies indicate that during the biotreatment several 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 solubilization of trace metals; and (6) the qualitative and quantitative chemical and physical changes appear to be microbial species dependent. Effects on heavy crude oils are also compared to those on lighter oils such as oils from the Wyoming petroleum reserve. Microbial oil interactions are monitored routinely by a consortium of analytical techniques which are continuously upgraded and are capable of multiparameter analysis. The results generated in fiscal year 1991, describing (1) through (6), are presented and discussed in this report.

  15. 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.

    PubMed

    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) in the quantities of tet (except tet(W)) and intI1 genes was observed at Fe(0) dosage of 5 g/L, whereas no significant differences (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.

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

    NASA Astrophysics Data System (ADS)

    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.

  17. Acetate treatment in 70 degrees C upflow anaerobic sludge-blanket (UASB) reactors: start-up with thermophilic inocula and the kinetics of the UASB sludges.

    PubMed

    Lepistö, R; Rintala, J A

    1995-11-01

    This study focused on the use the thermophilic anaerobic granulae in the start-up of 70 degrees C acetate-fed upflow anaerobic sludge-blanket (UASB) reactors and the kinetics of granulae grown at 70 degrees C. In the UASB reactors, chemical oxygen demand removal commenced within 48 h of the start-up. The maximum reduction in chemical oxygen demand was 84% with the feed containing yeast and 71% without a yeast supplement. In the bioassays, the yeast-grown sludge converted 98% of the acetate consumed to methane as compared to 92% for the sludge grown without yeast. The highest initial specific methane production rate (mu-CH4) of the UASB sludges grown at 70 degrees C was 0.088 h(-1) at an acetate concentration of 4.6mM. The higher initial acetate concentration was found to prolong the lag-phase in methane production significantly and to decrease mu-CH4. The half-saturation constant (Ks), the inhibition constant (Ki), the inhibition response coefficient (n) and the mu-CH4-max, calculated according to a modified Haldane equation, were 1.5 mM, 2.8 mM, 0.8 and 0.28 h(-1), respectively. The prolonged starvation of the 70 degrees C sludge (15 days) decreased the mu-CH4 from about 0.022 h(-1) to 0.011 h(-1) and increased the lag phase in methane production from 6 h to 24 h as compared with non-starved sludge.

  18. Anaerobaculum mobile sp. nov., a novel anaerobic, moderately thermophilic, peptide-fermenting bacterium that uses crotonate as an electron acceptor, and emended description of the genus Anaerobaculum.

    PubMed

    Menes, Rodolfo Javier; Muxí, Lucía

    2002-01-01

    A novel anaerobic, moderately thermophilic, peptide-fermenting bacterium, strain NGA(T), was isolated from an anaerobic wool-scouring wastewater treatment lagoon. The cells were gram-negative, straight rods of 0.5-1.0 x 2.0-4.0 microm, motile by means of a single flagellum. The DNA G+C content was 51.5 mol%. The optimum pH and temperature range for growth were 6.6-7.3 and 55-60 degrees C, respectively. The optimum NaCl concentration was 0.08 g l(-1). The bacterium fermented organic acids (malate, tartrate, pyruvate, glycerol and fumarate), a few carbohydrates (starch, glucose, fructose and gluconate), Casamino acids, tryptone and yeast extract. Carbohydrates and organic acids were converted to acetate, hydrogen and CO2. The bacterium oxidized leucine to isovalerate with crotonate as an electron acceptor, but not in co-culture with Methanothermobacter thermoautotrophicus DSM 3720T. Thiosulfate, sulfur and cystine were reduced to sulfide and crotonate was reduced to butyrate with glucose and tryptone-yeast extract as electron donors. Phylogenetic analysis of the 16S rRNA gene indicated that strain NGA(T) was related to Anaerobaculum thermoterrenum (98% similarity), the only described species of the genus. The DNA-DNA hybridization value for strain NGA(T) and A. thermoterrenum ACM 5076T was 40.8%. On the basis of these results, strain NGA(T) is proposed as a novel species of the genus Anaerobaculum, namely Anaerobaculum mobile sp. nov. The type strain is NGA(T) (= DSM 13181T =ATCC BAA-54T).

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

    PubMed

    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.

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

    PubMed Central

    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

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

    PubMed

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

    2015-06-01

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

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

    PubMed

    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.

  3. Microbial community structure and dynamics in two-stage vs single-stage thermophilic anaerobic digestion of mixed swine slurry and market bio-waste.

    PubMed

    Merlino, Giuseppe; Rizzi, Aurora; Schievano, Andrea; Tenca, Alberto; Scaglia, Barbara; Oberti, Roberto; Adani, Fabrizio; Daffonchio, Daniele

    2013-04-15

    The microbial community of a thermophilic two-stage process was monitored during two-months operation and compared to a conventional single-stage process. Qualitative and quantitative microbial dynamics were analysed by Denaturing Gradient Gel Electrophoresis (DGGE) and real-time PCR techniques, respectively. The bacterial community was dominated by heat-shock resistant, spore-forming clostridia in the two-stage process, whereas a more diverse and dynamic community (Firmicutes, Bacteroidetes, Synergistes) was observed in the single-stage process. A significant evolution of bacterial community occurred over time in the acidogenic phase of the two-phase process with the selection of few dominant species associated to stable hydrogen production. The archaeal community, dominated by the acetoclastic Methanosarcinales in both methanogen reactors, showed a significant diversity change in the single-stage process after a period of adaptation to the feeding conditions, compared to a constant stability in the methanogenic reactor of the two-stage process. The more diverse and dynamic bacterial and archaeal community of single-stage process compared to the two-stage process accounted for the best degradation activity, and consequently the best performance, in this reactor. The microbiological perspective proved a useful tool for a better understanding and comparison of anaerobic digestion processes. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

    PubMed

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

    2014-07-01

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

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

    PubMed

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

    2013-12-01

    Coffee grounds are deemed to be difficult for degradation by thermophilic anaerobic process. In this research, a 7 L AnMBR accepting coffee grounds was operated for 82 days and failed with pH dropping to 6.6. The deficiency of micronutrients in the reactor was identified. The system was recovered by supplying micronutrient, pH adjustment and influent ceasing for 22 days. In the subsequent 160 days of co-digestion experiment, waste activated sludge (15% in the mixture) was mixed into coffee grounds. The COD conversion efficiency of 67.4% was achieved under OLR of 11.1 kg-COD/m(3) d and HRT of 20 days. Tannins was identified affecting protein degradation by a batch experiment. Quantitative supplements of NH4HCO3 (0.12 g-N/g-TSin) were effective to maintain alkalinity and pH. The solid concentration in the AnMBR reached 75 g/L, but it did not significantly affect membrane filtration under a flux of 5.1 L/m(2) h. Soluble carbohydrate, lipid and protein were partially retained by the membrane. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

    PubMed

    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.

  7. Full-scale class A biosolids production by two-stage continuous-batch thermophilic anaerobic digestion at the hyperion treatment plant, Los Angeles, California.

    PubMed

    Iranpour, Reza; Cox, Huub H J; Fan, Steve; Abkian, Varouj; Minamide, Traci; Kearney, Ray J; Haug, Roger T

    2006-10-01

    The City of Los Angeles Hyperion Treatment Plant (HTP) (California) converted its anaerobic digesters to thermophilic operation to produce Class A biosolids. Phase IV tests demonstrated compliance of a two-stage, continuous-batch process with Alternative 1 of U.S. Environmental Protection Agency 40 CFR Part 503 (U.S. EPA, 1993), which defines the time-temperature requirement for batch treatment (T > or = 56.3 degrees C at 16-h holding). Fecal coliforms, Salmonella sp., viable helminth ova, and enteric viruses were not detected in biosolids in the postdigestion train, including the truck-loading facility and the farm for land application as the last points of plant control where compliance is to be demonstrated. The same results were achieved during Phase V tests, after lowering the second-stage holding temperature to 52.6 degrees C to reduce the elevated methyl mercaptan production that was observed during Phase IV. Hence, the Phase V process complied with Alternative 3 of 40 CFR Part 503. Currently, HTP operates its digesters under the same conditions as tested in Phase V. In 2003, monthly monitoring of the biosolids at the truck-loading facility and the farm for land application demonstrated consistent compliance with Alternative 3.

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

    PubMed

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

    2016-03-01

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

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

    PubMed

    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.

  10. Caldithrix abyssi gen. nov., sp. nov., a nitrate-reducing, thermophilic, anaerobic bacterium isolated from a Mid-Atlantic Ridge hydrothermal vent, represents a novel bacterial lineage.

    PubMed

    Miroshnichenko, Margarita L; Kostrikina, Nadezhda A; Chernyh, Nikolai A; Pimenov, Nikolai V; Tourova, Tatyana P; Antipov, Alexei N; Spring, Stefan; Stackebrandt, Erko; Bonch-Osmolovskaya, Elizaveta A

    2003-01-01

    A novel, moderately thermophilic, strictly anaerobic, mixotrophic bacterium, designated strain LF13T, was isolated from a deep-sea hydrothermal chimney sample that was collected at a vent site at 14 degrees 45' N, 44 degrees 59' W on the Mid-Atlantic Ridge. Cells were Gram-negative, thin, non-motile rods of variable length. Strain LF13T grew optimally at pH 6.8-7.0 and 60 degrees C with 2.5% (w/v) NaCl. It grew chemo-organoheterotrophically, fermenting proteinaceous substrates, pyruvate and Casamino acids. The strain was able to grow by respiration, utilizing molecular hydrogen (chemolithoheterotrophically) or acetate as electron donors and nitrate as an electron acceptor. Ammonium was formed in the course of denitrification. One-hundred milligrams of yeast extract per litre were required for growth of the strain. The G + C content of the genomic DNA of strain LF13T was 42.5 mol%. Neither 16S rDNA sequence similarity values nor phylogenetic analysis unambiguously related strain LF13T with members of any recognized bacterial phyla. On the basis of 16S rDNA sequence comparisons, and in combination with physiological and morphological traits, a novel genus, Caldithrix, is proposed, with strain LF13T (= DSM 13497T =VKM B-2286T) representing the type species, Caldithrix abyssi.

  11. Thermovirga lienii gen. nov., sp. nov., a novel moderately thermophilic, anaerobic, amino-acid-degrading bacterium isolated from a North Sea oil well.

    PubMed

    Dahle, Håkon; Birkeland, Nils-Kåre

    2006-07-01

    A novel anaerobic, moderately thermophilic bacterium, strain Cas60314(T), was isolated from hot oil-well production water obtained from an oil reservoir in the North Sea. The cells were Gram-negative, motile, straight rods. The salinity and pH growth optima were 2.0-3.0 % NaCl and 6.5-7.0, respectively. The optimum temperature was 58 degrees C. Strain Cas60314(T) had a fermentative type of metabolism and utilized proteinous substrates, some single amino acids and a limited number of organic acids, but not sugars, fatty acids or alcohols. Cystine and elemental sulfur were reduced to sulfide. The G+C content of the DNA was 46.6 mol%. On the basis of phenotypic and phylogenetic features, it is proposed that this isolate represents a novel genus and species with the name Thermovirga lienii gen. nov., sp. nov. within the family Syntrophomonadaceae. The proposed type strain is strain Cas60314(T) (=DSM 17291(T)=ATTC BAA-1197(T)).

  12. Performance of up-flow anaerobic fixed bed reactor of the treatment of sugar beet pulp lixiviation in a thermophilic range.

    PubMed

    Montañés Alonso, Rocío; Pérez García, Montserrat; Solera del Río, Rosario

    2014-02-01

    The acclimatization and performance study of lixiviation of sugar beet pulp are carried out in upflow anaerobic fixed bed reactor in thermophilic range of temperature (55°C). Several hydraulic retention time is conducted (11, 8, 6, 4, 2, and 1.5 days). The performance study showed that Chemical Oxygen Demand removal efficiency is 90% for 6 days-HRT. While COD removal efficiency was reduced within the range of 74.3% and 59.4% in others HRT. Organic loading rates greater than 10 kg COD/m(3)d in influent, (2 days-HRT), produces a destabilization of the process due to total acidity accumulation in reactors although is the HRT with highest methane production. The results showed that an increase in OLR was directly correlated with active biomass inside reactor but not with the amount in microbial community. The bacterial concentration inside the reactor is strongly influenced by the content of microorganisms in the lixiviation of sugar beet pulp.

  13. Combined mesophilic anaerobic and thermophilic aerobic digestion process for high-strength food wastewater to increase removal efficiency and reduce sludge discharge.

    PubMed

    Jang, H M; Park, S K; Ha, J H; Park, J M

    2014-01-01

    In this study, a process that combines the mesophilic anaerobic digestion (MAD) process with thermophilic aerobic digestion (TAD) for high-strength food wastewater (FWW) treatment was developed to examine the removal of organic matter and methane production. All effluent discharged from the MAD process was separated into solid and liquid portions. The liquid part was discarded and the sludge part was passed to the TAD process for further degradation. Then, the digested sludge from the TAD process was recycled back to the MAD unit to achieve low sludge discharge from the combined process. The reactor combination was operated in two phases: during Phase I, 40 d of total hydraulic retention time (HRT) was applied; during Phase II, 20 d was applied. HRT of the TAD process was fixed at 5 d. For a comparison, a control process (single-stage MAD) was operated with the same HRTs of the combined process. Our results indicated that the combined process showed over 90% total solids, volatile solids and chemical oxygen demand removal efficiencies. In addition, the combined process showed a significantly higher methane production rate than that of the control process. Consequently, the experimental data demonstrated that the combined MAD-TAD process was successfully employed for high-strength FWW treatment with highly efficient organic matter reduction and methane production.

  14. Impact of high external circulation ratio on the performance of anaerobic reactor treating coal gasification wastewater under thermophilic condition.

    PubMed

    Jia, Shengyong; Han, Hongjun; Zhuang, Haifeng; Hou, Baolin; Li, Kun

    2015-09-01

    A laboratory-scale external circulation anaerobic reactor (ECAR) was developed to treat actual coal gasification wastewater. The external circulation ratio (R) was selected as the main operating variable for analysis. From the results, with the hydraulic retention time of 50h, pH > 8.0 and R of 3, the COD, total phenols, volatile phenol and NH4(+)-N removal efficiencies were remarkably increased to 10 ± 2%, 22 ± 5%, 18 ± 1%, and -1 ± 2%, respectively. Besides, increasing R resulted in more transformation from bound extracellular polymeric substances (EPS) to free EPS in the liquid and the particle size distribution of anaerobic granular sludge accumulated in the middle size range of 1.0-2.5mm. Results showed the genus Saccharofermentans dominanted in the ECAR and the bacterial community shift was observed at different external circulation ratio, influencing the pollutants removal profoundly.

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

    PubMed

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

    2016-08-01

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

  16. Thermophilic degradation of cellulosic biomass

    NASA Astrophysics Data System (ADS)

    Ng, T.; Zeikus, J. G.

    1982-12-01

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

  17. Biogas production performance of mesophilic and thermophilic anaerobic co-digestion with fat, oil, and grease in semi-continuous flow digesters: effects of temperature, hydraulic retention time, and organic loading rate.

    PubMed

    Li, C; Champagne, P; Anderson, B C

    2013-01-01

    Anaerobic co-digestions with fat, oil, and grease (FOG) were investigated in semi-continuous flow digesters under various operating conditions. The effects of hydraulic retention times (HRTs) of 12 and 24 days, organic loading rates (OLRs) between 1.19 and 8.97 gTVS/Ld, and digestion temperatures of 37 degrees C and 55 degrees C on biogas production were evaluated. It was proposed that, compared to anaerobic digestion with wastewater treatment plant sludge (primary raw sludge), semi-continuous flow anaerobic co-digestion with FOG could effectively enhance biogas and methane production. Thermophilic (55 degrees C) co-digestions exhibited higher biogas production and degradation of organics than mesophilic co-digestions. The best biogas production rate of 17.4 +/- 0.86 L/d and methane content 67.9 +/- 1.46% was obtained with a thermophilic co-digestion at HRT = 24 days and OLR = 2.43 +/- 0.15 g TVS/Ld. These were 32.8% and 7.10% higher than the respective values from the mesophilic co-digestion under similar operating conditions.

  18. [Thermophilic prokaryotes from deep subterranean habitats].

    PubMed

    Slobodkin, A I; Slobodkina, G B

    2014-01-01

    The deep continental biosphere consists of geologically isolated ecosystems differing in their physicochemical, geological, and trophic parameters. Most of the deep ecosystems exist at elevated temperatures (50-120 degrees C), which favor the development of thermophilic microorganisms. In many cases, indigenous nature of subsurface microorganisms is questionable due to problems of collecting representative and non-contaminated samples. In spite of the numerous studies on the deep biosphere microbial communities, the number of cultivated thermophiles isolated from subsurface environments not associated with petroleum deposits does not exceed 30 species. More than half of the thermophilic species isolated from deep subsurface belong to the Firmicutes. Majority of the underground thermophiles are subsurface strict or facultative anaerobes, with capacity for sulfate and iron reduction are notably widespread. Most thermophilic subsurface microorganisms are organotrophs, although chemolithoautotrophic thermophiles also have been reported. This review deals with the phylogenetic diversity and physiological properties of the cultivated thermophilic prokaryotes isolated from various deep subterranean habitats.

  19. Anaerobic desulfurization of ground rubber with the thermophilic archaeon Pyrococcus furiosus--a new method for rubber recycling.

    PubMed

    Bredberg, K; Persson, J; Christiansson, M; Stenberg, B; Holst, O

    2001-01-01

    The anaerobic sulfur-reducing archaeon Pyrococcus furiosus was investigated regarding its capacity to desulfurize rubber material. The microorganism's sensitivity towards common rubber elastomers and additives was tested and several were shown to be toxic to P. furiosus. The microorganism was shown to utilize sulfur in vulcanized natural rubber and an increase in cell density was obtained when cultivated in the presence of spent tire rubber. Ethanol-leached cryo-ground tire rubber treated with P. furiosus for 10 days was vulcanized together with virgin rubber material (15% w/w) and the mechanical properties of the resulting material were determined. The increase in the stress at break value and the decrease in swell ratio and stress relaxation rate obtained for material containing microbially treated rubber (compared to untreated material) show the positive effects of microbial desulfurization on rubber.

  20. [Diversity of Cuproproteins and Copper Homeostasis Systems in Melioribacter roseus, a Facultatively Anaerobic Thermophilic Member of a New Phylum Ignavibacteriae].

    PubMed

    Karnachuk, O V; Gavrilov, S N; Avakyan, M R; Podosokorskaya, O A; Frank, Yu A; Bonch-Osmolovskaya, E A; Kublanov, I B

    2015-01-01

    The genome of Melioribacter roseus, one of two members of the recently described phylum Ignavibacteriae, was searched for the genes encoding proteins associated with copper transport or containing copper as cofactors, and the effect of Cu2+ concentration in the medium on M. roseus growth was investigated. Genomic analysis revealed a variety of copper-containing oxidoreductases in this facultative anaerobe. Three ATPases responsible for copper transport were identified. One of them (MROS_1511) was.probably involved in assembly of the copper-containing cytochrome c oxidase, while two others (MROS_0327 and MROS_0791) probably carried out a detoxification function. The presence of several copper-containing oxidoreductases and copper homeostasis systems in M. roseus is in agreement with the previously hypothesized origin of the phylum Ignavibacteriae from an aerobic ancestor common with those of Bacteroidetes and Chlorobi.

  1. Overcoming organic and nitrogen overload in thermophilic anaerobic digestion of pig slurry by coupling a microbial electrolysis cell.

    PubMed

    Cerrillo, Míriam; Viñas, Marc; Bonmatí, August

    2016-09-01

    The combination of the anaerobic digestion (AD) process with a microbial electrolysis cell (MEC) coupled to an ammonia stripping unit as a post-treatment was assessed both in series operation, to improve the quality of the effluent, and in loop configuration recirculating the effluent, to increase the AD robustness. The MEC allowed maintaining the chemical oxygen demand removal of the whole system of 46±5% despite the AD destabilization after doubling the organic and nitrogen loads, while recovering 40±3% of ammonia. The AD-MEC system, in loop configuration, helped to recover the AD (55% increase in methane productivity) and attained a more stable and robust operation. The microbial population assessment revealed an enhancement of AD methanogenic archaea numbers and a shift in eubacterial population. The AD-MEC combined system is a promising strategy for stabilizing AD against organic and nitrogen overloads, while improving the quality of the effluent and recovering nutrients for their reutilization.

  2. Balnearium lithotrophicum gen. nov., sp. nov., a novel thermophilic, strictly anaerobic, hydrogen-oxidizing chemolithoautotroph isolated from a black smoker chimney in the Suiyo Seamount hydrothermal system.

    PubMed

    Takai, Ken; Nakagawa, Satoshi; Sako, Yoshihiko; Horikoshi, Koki

    2003-11-01

    A novel, extremely thermophilic bacterium, designated strain 17S(T), was isolated from a deep-sea hydrothermal vent chimney at the Suiyo Seamount in the Izu-Bonin Arc, Japan. The cells were rods with no apparent motility, most of which were narrow in the middle in the exponential-growth phase and had several polar flagella at both ends. Growth was observed between 45 and 80 degrees C (optimum temperature, 70-75 degrees C; doubling time, 80 min) and between pH 5.0 and 7.0 (optimum pH, 5.4). The isolate was a strictly anaerobic chemolithoautotroph that was capable of using molecular hydrogen as its sole energy source and carbon dioxide as its sole carbon source. Elemental sulfur (S(0)) was required for growth as an electron acceptor. The G+C content of the genomic DNA was 34.6 mol%. Phylogenetic analysis based on 16S rDNA sequences indicated that the isolate was related to Thermovibrio ruber ED11/3LLK(T) and Desulfurobacterium thermolithotrophum BSA(T), whilst it appeared to be a novel lineage prior to the divergence of these genera. This isolate could also be differentiated from both T. ruber ED11/3LLK(T) and D. thermolithotrophum BSA(T) on the basis of physiological properties. The name Balnearium lithotrophicum gen. nov., sp. nov. is proposed for this isolate (type strain, 17S(T)=JCM 11970(T)=ATCC BAA-736(T)).

  3. Petrothermobacter organivorans gen. nov., sp. nov., a thermophilic, strictly anaerobic bacterium of the phylum Deferribacteres isolated from a deep subsurface oil reservoir.

    PubMed

    Tamazawa, Satoshi; Mayumi, Daisuke; Mochimaru, Hanako; Sakata, Susumu; Maeda, Haruo; Wakayama, Tatsuki; Ikarashi, Masayuki; Kamagata, Yoichi; Tamaki, Hideyuki

    2017-09-12

    A novel thermophilic, anaerobic, chemoheterotrophic, acetate-oxidizing and iron(III)-, manganese(IV)-, nitrate- and sulfate-reducing bacterium, designated strain ANAT, was isolated from a deep subsurface oil field in Japan (Yabase oil field, Akita Pref.). Cells of strain ANAT were Gram-stain-negative, non-motile, non-spore forming and slightly curved or twisted rods (1.5-5.0 µm long and 0.6-0.7 µm wide). The isolate grew at 25-60 °C (optimum 55 °C) and pH 6.0-8.0 (optimum pH 7.0). The isolate was capable of reducing iron(III), manganese(IV), nitrate and sulfate as an electron acceptor. The isolate utilized a limited range of electron donors such as acetate, lactate, pyruvate and yeast extract for iron reduction. Strain ANAT also used pyruvate, fumarate, succinate, malate, yeast extract and peptone for fermentative growth. The major respiratory quinones were menaquinone-7(H8) and menaquinone-8. The strain contained C18 : 0, iso-C18 : 0 and C16 : 0 as the major cellular fatty acids. The G+C content of the genomic DNA was 34.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain ANAT was closely related to Calditerrivibrio nitroreducens in the phylum Deferribacteres with low sequence similarities (89.5 %), and formed a distinct clade within the family Deferribacteraceae. In addition, the isolate is the first sulfate-reducing member of the phylum Deferribacteres. Based on phenotypic, chemotaxonomic and phylogenetic properties, a novel genus and species, Petrothermobacter organivorans gen. nov., sp. nov., is proposed for the isolate (type strain=ANAT= NBRC 112621T=DSM 105015T).

  4. 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.

    PubMed

    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.

  5. 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

    SciTech Connect

    Svetlitshnyi, V.; Wiegel, J.; Rainey, F.

    1996-10-01

    Three strains of an anaerobic thermophilic organoheterotrophic lipolytic alkalitolerant bacterium, Thermosyntropha lipolytica gen. nov., sp. nov. (type strain JW/VS-264{sup T}; 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 [pH{sup 25{degrees}C}] was 7.15 to 9.5, with an optimum between 8.1 and 8.9 (pH{sup 60{degrees}C} of 7.6 and 8.1). At a pH{sup 25{degrees}C} of 8.5 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 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.

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

    SciTech Connect

    Trebbau, G.; Fernandez, B.; Marin, A.

    1995-12-31

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

  7. Two-stage vs single-stage thermophilic anaerobic digestion: comparison of energy production and biodegradation efficiencies.

    PubMed

    Schievano, Andrea; Tenca, Alberto; Scaglia, Barbara; Merlino, Giuseppe; Rizzi, Aurora; Daffonchio, Daniele; Oberti, Roberto; Adani, Fabrizio

    2012-08-07

    Two-stage anaerobic digestion (AD) for integrated biohydrogen and biomethane production from organic materials has been reported to promise higher process efficiency and energy recoveries as compared to traditional one-stage AD. This work presents a comparison between two-stage (reactors R1 and R2) and one-stage (reactor R3) AD systems, fed with identical organic substrates and loading rates, focusing the attention on chemical and microbiological aspects. Contrary to previous experiences, no significant differences in overall energy recovery were found for the two-stage and one-stage AD systems. However, an accumulation in R2 of undegraded intermediate metabolites (volatile fatty acids, ketones, amines, amino acids, and phenols) was observed by GC-MS. These compounds were thought to be both cause and effect of this partial inefficiency of the two-stage system, as confirmed also by the less diverse, and thereby less efficient, population of fermentative bacteria observed (by PCR-DGGE) in R2. The extreme environment of R1 (low pH and high metabolites concentrations) probably acted as selector of metabolic pathways, favoring H(2)-producing bacteria able to degrade such a wide variability of intermediate metabolites while limiting other strains. Therefore, if two-stage AD may potentially lead to higher energy recoveries, further efforts should be directed to ensure process efficiency and stability.

  8. Organic loading rate impact on biohydrogen production and microbial communities at anaerobic fluidized thermophilic bed reactors treating sugarcane stillage.

    PubMed

    Santos, Samantha Christine; Rosa, Paula Rúbia Ferreira; Sakamoto, Isabel Kimiko; Varesche, Maria Bernadete Amâncio; Silva, Edson Luiz

    2014-05-01

    This study aimed to evaluate the effect of high organic loading rates (OLR) (60.0-480.00 kg COD m(-3)d(-1)) on biohydrogen production at 55°C, from sugarcane stillage for 15,000 and 20,000 mg CODL(-1), in two anaerobic fluidized bed reactors (AFBR1 and AFBR2). It was obtained, for H2 yield and content, a decreasing trend by increasing the OLR. The maximum H2 yield was observed in AFBR1 (2.23 mmol g COD added(-1)). The volumetric H2 production was proportionally related to the applied hydraulic retention time (HRT) of 6, 4, 2 and 1h and verified in AFBR1 the highest value (1.49 L H2 h(-1)L(-1)). Among the organic acids obtained, there was a predominance of lactic acid (7.5-22.5%) and butyric acid (9.4-23.8%). The microbial population was set with hydrogen-producing fermenters (Megasphaera sp.) and other organisms (Lactobacillus sp.).

  9. Efficient Degradation of Lignocellulosic Plant Biomass, without Pretreatment, by the Thermophilic Anaerobe “Anaerocellum thermophilum” DSM 6725▿

    PubMed Central

    Yang, Sung-Jae; Kataeva, Irina; Hamilton-Brehm, Scott D.; Engle, Nancy L.; Tschaplinski, Timothy J.; Doeppke, Crissa; Davis, Mark; Westpheling, Janet; Adams, Michael W. W.

    2009-01-01

    Very few cultivated microorganisms can degrade lignocellulosic biomass without chemical pretreatment. We show here that “Anaerocellum thermophilum” DSM 6725, an anaerobic bacterium that grows optimally at 75°C, efficiently utilizes various types of untreated plant biomass, as well as crystalline cellulose and xylan. These include hardwoods such as poplar, low-lignin grasses such as napier and Bermuda grasses, and high-lignin grasses such as switchgrass. The organism did not utilize only the soluble fraction of the untreated biomass, since insoluble plant biomass (as well as cellulose and xylan) obtained after washing at 75°C for 18 h also served as a growth substrate. The predominant end products from all growth substrates were hydrogen, acetate, and lactate. Glucose and cellobiose (on crystalline cellulose) and xylose and xylobiose (on xylan) also accumulated in the growth media during growth on the defined substrates but not during growth on the plant biomass. A. thermophilum DSM 6725 grew well on first- and second-spent biomass derived from poplar and switchgrass, where spent biomass is defined as the insoluble growth substrate recovered after the organism has reached late stationary phase. No evidence was found for the direct attachment of A. thermophilum DSM 6725 to the plant biomass. This organism differs from the closely related strain A. thermophilum Z-1320 in its ability to grow on xylose and pectin. Caldicellulosiruptor saccharolyticus DSM 8903 (optimum growth temperature, 70°C), a close relative of A. thermophilum DSM 6725, grew well on switchgrass but not on poplar, indicating a significant difference in the biomass-degrading abilities of these two otherwise very similar organisms. PMID:19465524

  10. Influence of high gas production during thermophilic anaerobic digestion in pilot-scale and lab-scale reactors on survival of the thermotolerant pathogens Clostridium perfringens and Campylobacter jejuni in piggery wastewater.

    PubMed

    Skillman, L C; Bajsa, O; Ho, L; Santhanam, B; Kumar, M; Ho, G

    2009-07-01

    Safe reuse of animal wastes to capture energy and nutrients, through anaerobic digestion processes, is becoming an increasingly desirable solution to environmental pollution. Pathogen decay is the most important safety consideration and is in general, improved at elevated temperatures and longer hydraulic residence times. During routine sampling to assess pathogen decay in thermophilic digestion, an inversely proportional relationship between levels of Clostridium perfringens and gas production was observed. Further samples were collected from pilot-scale, bench-scale thermophilic reactors and batch scale vials to assess whether gas production (predominantly methane) could be a useful indicator of decay of the thermotolerant pathogens C. perfringens and Campylobacter jejuni. Pathogen levels did appear to be lower where gas production and levels of methanogens were higher. This was evident at each operating temperature (50, 57, 65 degrees C) in the pilot-scale thermophilic digesters, although higher temperatures also reduced the numbers of pathogens detected. When methane production was higher, either when feed rate was increased, or pH was lowered from 8.2 (piggery wastewater) to 6.5, lower numbers of pathogens were detected. Although a number of related factors are known to influence the amount and rate of methane production, it may be a useful indicator of the removal of the pathogens C. perfringens and C. jejuni.

  11. Thermosinus carboxydivorans gen. nov., sp. nov., a new anaerobic, thermophilic, carbon-monoxide-oxidizing, hydrogenogenic bacterium from a hot pool of Yellowstone National Park.

    PubMed

    Sokolova, Tatyana G; González, Juan M; Kostrikina, Nadezhda A; Chernyh, Nikolai A; Slepova, Tatiana V; Bonch-Osmolovskaya, Elizaveta A; Robb, Frank T

    2004-11-01

    A new anaerobic, thermophilic, facultatively carboxydotrophic bacterium, strain Nor1(T), was isolated from a hot spring at Norris Basin, Yellowstone National Park. Cells of strain Nor1(T) were curved motile rods with a length of 2.6-3 microm, a width of about 0.5 microm and lateral flagellation. The cell wall structure was of the Gram-negative type. Strain Nor1(T) was thermophilic (temperature range for growth was 40-68 degrees C, with an optimum at 60 degrees C) and neutrophilic (pH range for growth was 6.5-7.6, with an optimum at 6.8-7.0). It grew chemolithotrophically on CO (generation time, 1.15 h), producing equimolar quantities of H(2) and CO(2) according to the equation CO+H(2)O-->CO(2)+H(2). During growth on CO in the presence of ferric citrate or amorphous ferric iron oxide, strain Nor1(T) reduced ferric iron but produced H(2) and CO(2) at a ratio close to 1 : 1, and growth stimulation was slight. Growth on CO in the presence of sodium selenite was accompanied by precipitation of elemental selenium. Elemental sulfur, thiosulfate, sulfate and nitrate did not stimulate growth of strain Nor1(T) on CO and none of these chemicals was reduced. Strain Nor1(T) was able to grow on glucose, sucrose, lactose, arabinose, maltose, fructose, xylose and pyruvate, but not on cellobiose, galactose, peptone, yeast extract, lactate, acetate, formate, ethanol, methanol or sodium citrate. During glucose fermentation, acetate, H(2) and CO(2) were produced. Thiosulfate was found to enhance the growth rate and cell yield of strain Nor1(T) when it was grown on glucose, sucrose or lactose; in this case, acetate, H(2)S and CO(2) were produced. In the presence of thiosulfate or ferric iron, strain Nor1(T) was also able to grow on yeast extract. Lactate, acetate, formate and H(2) were not utilized either in the absence or in the presence of ferric iron, thiosulfate, sulfate, sulfite, elemental sulfur or nitrate. Growth was completely inhibited by penicillin, ampicillin, streptomycin

  12. Draft Genome Sequence of the Cellulolytic and Xylanolytic Thermophile Clostridium clariflavum Strain 4-2a.

    PubMed

    Rooney, Elise A; Rowe, Kenneth T; Guseva, Anna; Huntemann, Marcel; Han, James K; Chen, Amy; Kyrpides, Nikos C; Mavromatis, Konstantinos; Markowitz, Victor M; Palaniappan, Krishna; Ivanova, Natalia; Pati, Amrita; Liolios, Konstantinos; Nordberg, Henrik P; Cantor, Michael N; Hua, Susan X; Shapiro, Nicole; Woyke, Tanja; Lynd, Lee R; Izquierdo, Javier A

    2015-07-23

    Clostridium clariflavum strain 4-2a, a novel strain isolated from a thermophilic biocompost pile, has demonstrated an extensive capability to utilize both cellulose and hemicellulose under thermophilic anaerobic conditions. Here, we report the draft genome of this strain.

  13. CHANGES IN THE ANAEROBIC THRESHOLD IN AN ANNUAL CYCLE OF SPORT TRAINING OF YOUNG SOCCER PLAYERS

    PubMed Central

    Andrzejewski, M.; Wieczorek, A.; Barinow-Wojewódzki, A.; Jadczak, Ł.; Adrian, S.; Pietrzak, M.; Wieczorek, S.

    2013-01-01

    The aim of the study was to assess changes in the anaerobic threshold of young soccer players in an annual training cycle. A group of highly trained 15-18 year old players of KKS Lech Poznań were tested. The tests included an annual training macrocycle, and its individual stages resulted from the time structure of the sports training. In order to assess the level of exercise capacities of the players, a field exercise test of increasing intensity was carried out on a soccer pitch. The test made it possible to determine the 4 millimolar lactate threshold (T LA 4 mmol · l-1) on the basis of the lactate concentration in blood [LA], to establish the threshold running speed and the threshold heart rate [HR]. The threshold running speed at the level of the 4 millimolar lactate threshold was established using the two-point form of the equation of a straight line. The obtained indicators of the threshold running speed allowed for precise establishment of effort intensity used in individual training in developing aerobic endurance. In order to test the significance of differences in mean values between four dates of tests, a non-parametric Friedman ANOVA test was used. The significance of differences between consecutive dates of tests was determined using a post-hoc Friedman ANOVA test. The tests showed significant differences in values of selected indicators determined at the anaerobic threshold in various stages of an annual training cycle of young soccer players. The most beneficial changes in terms of the threshold running speed were noted on the fourth date of tests, when the participants had the highest values of 4.01 m · s-1 for older juniors, and 3.80 m · s-1 for younger juniors. This may be indicative of effective application of an individualized programme of training loads and of good preparation of teams for competition in terms of players’ aerobic endurance. PMID:24744480

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

    PubMed

    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

  15. Sporolituus thermophilus gen. nov., sp. nov., a citrate-fermenting thermophilic anaerobic bacterium from geothermal waters of the Great Artesian Basin of Australia.

    PubMed

    Ogg, Christopher D; Patel, Bharat K C

    2009-11-01

    A strictly anaerobic, sluggishly motile, spore-forming, thermophilic bacterium, designated strain AeG(T), was isolated from microbial mats colonizing a runoff channel formed by free-flowing thermal waters of a bore well (New Lorne Bore; registered number 17263) in the Great Artesian Basin, Australia. Cells of strain AeG(T) were curved rods (2.0-10.0x0.8-1.0 mum) and stained Gram-negative. The strain grew optimally in tryptone-yeast extract-citrate medium at 55 degrees C (range for growth between 45 and 60 degrees C) and pH 7.0 (range for growth between pH 6.5 and 8.0). Citrate and malate, but no other organic acids, carbohydrates or amino acids could be used in the presence of up to 0.1 % yeast extract. Although yeast extract and/or tryptone were required for growth on citrate, they did not support growth as sole carbon sources. Strain AeG(T) reduced thiosulfate and sulfite in the presence of 0.2 % yeast extract, but not Fe(III), Mn(IV), sulfate, elemental sulfur, nitrate or nitrite. Growth was inhibited by chloramphenicol, streptomycin, tetracycline, penicillin and ampicillin and in the presence of NaCl concentrations >1 %. The DNA G+C content was 55.4+/-1.0 mol% as determined by the thermal denaturation method. 16S rRNA gene sequence analysis indicated that strain AeG(T) was a member of the family Veillonellaceae, class 'Clostridia', phylum 'Firmicutes' and was most closely related to members of the genus Propionispora (mean 16S rRNA gene sequence similarity value to type strains was 90.8 %). Based on these results, strain AeG(T) is considered to represent a novel species in a new genus, for which the name Sporolituus thermophilus gen. nov., sp. nov. is proposed. The type strain of the type species is AeG(T) (=JCM 15556(T)=KCTC 5668(T)).

  16. Thermanaerovibrio velox sp. nov., a new anaerobic, thermophilic, organotrophic bacterium that reduces elemental sulfur, and emended description of the genus Thermanaerovibrio.

    PubMed

    Zavarzina, D G; Zhilina, T N; Tourova, T P; Kuznetsov, B B; Kostrikina, N A; Bonch-Osmolovskaya, E A

    2000-05-01

    A moderately thermophilic, organotrophic bacterium with vibrioid cells was isolated from a sample of a cyanobacterial mat from caldera Uzon, Kamchatka, Russia, and designated strain Z-9701T. Cells of strain Z-9701T were curved, Gram-negative rods, 0.5-0.7 x 2.5-5.0 microm in size, with tapering ends and with fast, wavy movement by means of lateral flagella located on the concave side of the cell. Colonies were small, white, irregular or round, 0.2 mm in diameter, and with even edges. Strain Z-9701T was an obligate anaerobe with a temperature optimum at 60-65 degrees C and a pH optimum at 7.3. It fermented glucose, fructose, mannose, N-acetyl-D-glucosamine, adonite, arginine, serine, peptone, yeast extract and Casamino acids. The fermentation products formed during growth on glucose were acetate, lactate, H2, CO2 and ethanol. Strain Z-9701T reduced elemental sulfur to H2S during organotrophic growth with glucose or peptides as energy and carbon sources. In the presence of S0, strain Z-9701T was capable of lithotrophic growth with molecular hydrogen as energy substrate and 0.1 g yeast extract l(-1) as carbon source. Sulfate, thiosulfate, nitrate, Fe(III) and sulfite were not reduced and did not stimulate growth. The G+C content of strain Z-9701T DNA was 54.6 mol%. The results of 16S rDNA sequence analyses revealed that strain Z-9701T belongs to the cluster within the Clostridium group formed by Thermanaerovibrio acidaminovorans, Dethiosulfovibrio peptidovorans, Anaerobaculum thermoterrenum and Aminobacterium colombiense, but the level of sequence similarity with the members of this cluster was not very high (87.6-92.2%). Among these organisms, Thermanaerovibrio acidaminovorans is phenotypically close to strain Z-9701T. However, the two organisms showed a relatively low level of similarity of their 16S rRNA sequences (92.2%) and of DNA-DNA hybridization (15 +/- 1%). Nevertheless, on the basis of the similar morphology and physiology of the new isolate and

  17. Thermoanaerobacter uzonensis sp. nov., an anaerobic thermophilic bacterium isolated from a hot spring within the Uzon Caldera, Kamchatka, Far East Russia.

    PubMed

    Wagner, Isaac D; Zhao, Weidong; Zhang, Chuanlun L; Romanek, Christopher S; Rohde, Manfred; Wiegel, Juergen

    2008-11-01

    Several strains of heterotrophic, anaerobic thermophilic bacteria were isolated from hot springs of the Uzon Caldera, Kamchatka, Far East Russia. Strain JW/IW010(T) was isolated from a hot spring within the West sector of the Eastern Thermal field, near Pulsating Spring in the Winding Creek area. Cells of strain JW/IW010(T) were straight to slightly curved rods, 0.5 mum in width and variable in length from 2 to 5 mum and occasionally up to 15 mum, and formed oval subterminal spores. Cells stained Gram-negative, but were Gram-type positive. Growth was observed between 32.5 and 69 degrees C with an optimum around 61 degrees C (no growth occurred at or below 30 degrees C, or at or above 72 degrees C). The pH(60 degrees C) range for growth was 4.2-8.9 with an optimum at 7.1 (no growth occurred at or below pH(60 degrees C) 3.9, or at 9.2 or above). The shortest observed doubling-time at pH(60 degrees C) 6.9 and 61 degrees C was 30 min. Strain JW/IW010(T) was chemo-organotrophic; yeast extract, peptone, Casamino acids and tryptone supported growth. Yeast extract was necessary for the utilization of non-proteinaceous substrates, and growth was observed with inulin, cellobiose, maltose, sucrose, glucose, fructose, galactose, mannose, xylose, trehalose, mannitol, pyruvate and crotonate. The G+C content of the genomic DNA of strain JW/IW010(T) was 33.6 mol% (HPLC method). The major phospholipid fatty acids were iso-15 : 0 (53.5 %), 15 : 0 (11.8 %), 16 : 0 (7.3 %), 10-methyl 16 : 0 (7.3 %) and anteiso-15 : 0 (5.3 %). 16S rRNA gene sequence analysis placed strain JW/IW010(T) in the genus Thermoanaerobacter of the family 'Thermoanaerobacteriaceae' (Firmicutes), with Thermoanaerobacter sulfurigignens JW/SL-NZ826(T) (97 % 16S rRNA gene sequence similarity) and Thermoanaerobacter kivui DSM 2030(T) (94.5 %) as the closest phylogenetic relatives with validly published names. The level of DNA-DNA relatedness between strain JW/IW010(T) and Thermoanaerobacter sulfurigignens JW/SL-NZ826

  18. 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.

    PubMed

    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.

  19. Thermophilic cellobiohydrolase

    DOEpatents

    Sapra, Rajat; Park, Joshua I.; Datta, Supratim; Simmons, Blake A.

    2017-04-18

    The present invention provides for a composition comprising a polypeptide comprising a first amino acid sequence having at least 70% identity with the amino acid sequence of Csac GH5 wherein said first amino acid sequence has a thermostable or thermophilic cellobiohydrolase (CBH) or exoglucanase activity.

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

    PubMed

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

    2014-01-01

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

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

    PubMed

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

    2016-01-01

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

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

    PubMed

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

    2014-01-01

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

  3. Isolation and characterization of Thermanaerothrix daxensis gen. nov., sp. nov., a thermophilic anaerobic bacterium pertaining to the phylum "Chloroflexi", isolated from a deep hot aquifer in the Aquitaine Basin.

    PubMed

    Grégoire, Patrick; Fardeau, Marie-Laure; Joseph, Manon; Guasco, Sophie; Hamaide, Francette; Biasutti, Sandra; Michotey, Valérie; Bonin, Patricia; Ollivier, Bernard

    2011-11-01

    A new strictly anaerobic thermophilic multicellular filamentous bacterium (0.2-0.3μm×>100μm), designated GNS-1(T), was isolated from a deep hot aquifer in France. It was non-motile, and stained Gram-negative. Optimal growth was observed at 65°C, pH 7.0, and 2gL(-1) of NaCl. Strain GNS-1(T) was chemoorganotrophic fermenting ribose, glucose, galactose, arabinose, fructose, mannose, maltose, sucrose, xylose, raffinose, pyruvate, and xylan. Yeast extract was required for growth. The end products of glucose fermentation were lactate, acetate, CO(2), and H(2). The G+C content of the DNA was 57.6mol%. Its closest phylogenetic relative was Bellilinea caldifistulae with 92.5% similarity. Based on phylogenetic, genotypic and phenotypic characteristics, strain GNS-1(T) (DSM 23592(T), JCM 16980(T)) is proposed to be assigned to a novel species of a novel genus within the class Anaerolineae (subphylum I), phylum "Chloroflexi", Thermanaerothrix daxensis gen. nov., sp. nov. The GenBank accession number is HM596746.

  4. Ignavibacterium album gen. nov., sp. nov., a moderately thermophilic anaerobic bacterium isolated from microbial mats at a terrestrial hot spring and proposal of Ignavibacteria classis nov., for a novel lineage at the periphery of green sulfur bacteria.

    PubMed

    Iino, Takao; Mori, Koji; Uchino, Yoshihito; Nakagawa, Tatsunori; Harayama, Shigeaki; Suzuki, Ken-Ichiro

    2010-06-01

    A moderately thermophilic chemoheterotrophic bacterium, strain Mat9-16(T), was isolated from microbial mats developed in hot spring water streams from Yumata, Nagano, Japan. Cells of strain Mat9-16(T) were strictly anaerobic, Gram-stain-negative, non-sporulating, non-motile and short to long rods (2.0-15.5 mum in length). Strain Mat9-16(T) grew fermentatively with optimum growth at 45 degrees C, pH 7.0-7.5 and 1 % NaCl (w/v). Phylogenetic analysis based on the 16S rRNA gene revealed that strain Mat9-16(T) was affiliated with an uncultivated lineage, and the nearest cultivated neighbours were green sulfur bacteria belonging to the class Chlorobea with 77-83 % sequence similarity. However, strain Mat9-16(T) could not grow phototrophically and did not possess light-harvesting structures, morphologically and genetically, such as the chlorosomes of green sulfur bacteria. On the basis of phenotypic features and phylogenetic position, a novel genus and species are proposed for strain Mat9-16(T), to be named Ignavibacterium album gen. nov., sp. nov. (=NBRC 101810(T) =DSM 19864(T)). We also propose to place the cultivated bacterial lineage accommodating the sole representative Mat9-16(T) in a novel class, Ignavibacteria classis nov. In addition, we present a formal description of the phylum-level taxon 'Chlorobi' as Chlorobi phyl. nov.

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

    SciTech Connect

    Shu-Ying Liu; Wiegel, J.; Rainey, F.A.

    1996-04-01

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

  6. Effects of size and thermophilic pre-hydrolysis of banana peel during anaerobic digestion, and biomethanation potential of key tropical fruit wastes.

    PubMed

    Odedina, Mary Jesuyemi; Charnnok, Boonya; Saritpongteeraka, Kanyarat; Chaiprapat, Sumate

    2017-07-11

    Methane production potential of tropical fruit wastes, namely lady-finger banana peel, rambutan waste and longan waste were compared using BMP assay and stoichiometric modified Buswell and Mueller equation. Methane yields based on volatile solid (VS) were in the order of ground banana peel, chopped banana peel, chopped longan waste, and chopped rambutan waste (330.6, 268.3, 234.6 and 193.2 mLCH4/gVS) that corresponded to their calculated biodegradability. In continuous operations of banana peel digestion at feed concentrations based on total solid (TS) 1-2%, mesophilic single stage digester run at 20-day hydraulic retention time (20-day HRT) failed at 2%TS, but successfully recovered at 1.5%TS. Pre-hydrolysis thermophilic reactor (4-d HRT) was placed as pre-treatment to mesophilic reactor (20-d HRT). Higher biogas (with an evolution of H2) and energy yields were obtained and greater system stability was achieved over the single stage digestion, particularly at higher solid feedstock. The best performance of two stage digestion was 68.5% VS destruction and energy yield of 2510.9kJ/kgVS added at a feed concentration of 2%TS. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Characterization and environmental studies of Pompano Beach anaerobic digestion facility. Annual report

    SciTech Connect

    Sengupta, S.; Wong, K.F.V.; Gerrish, H.P.; Nemerow, N.; Voorhees, S.A.; Daly, E.L. Jr.

    1982-03-01

    The findings of the characterization and environmental studies of an anaerobic digestion plant at Pompano Beach are presented. This 100 ton/day proof of concept plant which produces methane from municipal waste was built on an existing shredding and landfill site. The following aspects of the plant are covered: gas quality, airborne particulates, solid/liquid phases, microbiology, and leaching. (MHR)

  8. Characterization and environmental studies of Pompano Beach anaerobic digestion facility. Annual report

    SciTech Connect

    Sengupta, S; Gerrish, H P; Wong, K F; Nemerow, N; Daly, Jr, E L; Farooq, S; Chriswell, C

    1980-08-01

    Municipal solid wastes contain numerous substances of potential environmental concern. While some understanding of the composition of raw municipal waste and its leachate products is available, no information regarding characteristics of solid, liquid and gaseous outputs from anaerobic digestion exists. If centralized anaerobic digestion plants are to be environmentally viable, the characteristics and environmental effects of effluents from these plants must be acceptable. The environmental concerns are particularly acute where ground water supplies are precariously low and the water table is high, South Florida is such a location. A characterization and environmental study was initiated by the Resource Recovery Group on August 1978. The specific objectives are: (1) systematic characterization of solid, liquid and gaseous inputs and outputs; (2) investigations of leaching characteristic of output solid and liquid effluents, and the transport of pollutants to and through ground water systems; and (3) analysis of environmental and process parameters to obtain causal relationships.

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

    PubMed

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

    2004-04-01

    The conversion routes of carbon monoxide (CO) at 55 degrees C by full-scale grown anaerobic sludges treating paper mill and distillery wastewater were elucidated. Inhibition experiments with 2-bromoethanesulfonate (BES) and vancomycin showed that CO conversion was performed by a hydrogenogenic population and that its products, i.e. hydrogen and CO2, were subsequently used by methanogens, homo-acetogens or sulfate reducers depending on the sludge source and inhibitors supplied. Direct methanogenic CO conversion occurred only at low CO concentrations [partial pressure of CO (PCO) <0.5 bar (1 bar=10(5) Pa)] with the paper mill sludge. The presence of hydrogen decreased the CO conversion rates, but did not prevent the depletion of CO to undetectable levels (<400 ppm). Both sludges showed interesting potential for hydrogen production from CO, especially since after 30 min exposure to 95 degrees C, the production of CH4 at 55 degrees C was negligible. The paper mill sludge was capable of sulfate reduction with hydrogen, tolerating and using high CO concentrations (PCO>1.6 bar), indicating that CO-rich synthesis gas can be used efficiently as an electron donor for biological sulfate reduction.

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

    PubMed Central

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

    2015-01-01

    The biohydrogen productions from the organic fraction of municipal solid wastes (OFMSW) were studied under pH management intervals of 12 h (PM12) and 24 h (PM24) for temperature of 37 ± 0.1°C and 55 ± 0.1°C. The OFMSW or food waste (FW) along with its two components, noodle waste (NW) and rice waste (RW), was codigested with sludge to estimate the potential of biohydrogen production. The biohydrogen production was higher in all reactors under PM12 as compared to PM24. The drop in pH from 7 to 5.3 was observed to be appropriate for biohydrogen production via mesophilic codigestion of noodle waste with the highest biohydrogen yield of 145.93 mL/g CODremoved under PM12. When the temperature was increased from 37°C to 55°C and pH management interval was reduced from 24 h to 12 h, the biohydrogen yields were also changed from 39.21 mL/g CODremoved to 89.67 mL/g CODremoved, 91.77 mL/g CODremoved to 145.93 mL/g CODremoved, and 15.36 mL/g CODremoved to 117.62 mL/g CODremoved for FW, NW, and RW, respectively. The drop in pH and VFA production was better controlled under PM12 as compared to PM24. Overall, PM12 was found to be an effective mean for biohydrogen production through anaerobic digestion of food waste. PMID:26819952

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

    PubMed

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

    2015-01-01

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

  12. Characterization and environmental studies of Pompano Beach anaerobic digestion facility. Semi-annual report

    SciTech Connect

    Sengupta, S.; Wong, K.F.V.; Gerrish, H.P.; Nemerow, N.; Daly, E.L. Jr.; Chriswell, C.

    1981-02-01

    This report summarizes the results of routine monitoring of gas quality, airborne particulates, and solid and liquid phases of the Refcom facility at Pompano Beach, Florida. The plant produces methane from municipal wastes by anaerobic digestion. Bacteriological analysis of residual liquids and process streams were performed. Leaching studies with selected soils, filtrates and bottom layer muck were also conducted. A two-dimensional time model was developed. The first appendix contains the results of trace organic analysis of effluents from the facility. The results of environental studies on methane production are presented in the second appendix. The third appendix describes the gas analysis procedure and the gas composition of gas produced at the facility.

  13. Characterization and environmental studies of Pompano Beach anaerobic digestion facility. Semi-annual report

    SciTech Connect

    Sengupta, S; Farooq, S; Gerrish, H P; Wong, K F; Daly, Jr, E L; Chriswell, C

    1980-02-01

    Anaerobic digestion of municipal waste has been demonstrated to be feasible in bench scale experiments by Pfeffer (1974). Approximately, 50% reduction in mass and production of 6000 ft/sup 3/ of gas/ton have been estimated. The gas composition is estimated to be 50% methane and 50% carbon monoxide. The technical and economic feasibility of anaerobic digestion with an ultimate objective of commercialization are discussed. A plant has been built at Pompano Beach, Florida on an existing shredding and landfill operation site. The plant design capacity is 100 tons/day. Two digesters have been constructed to be used in parallel. The process consists of primary shredding, metal separation, secondary shredding, air classification and digestion of light fraction. Sewage sludge was used to seed the initial mixture in the digester. The output slurry is vacuum filtered and the filter cake disposed on an existing landfill. The filtrate is recycled. Excess filtrate is sprayed on the landfill. At present the output gas is being flared. A flow chart for the plant is presented. It is imperative that environmental investigations be conducted on new energy technology prior to commercialization. A project was initiated to characterize all input and output streams and to assess the potential for ground water contamination by landfill disposal of effluents. Detailed chemical, biological and physical characterization efforts supported by leaching and modelling studies are being conducted to achieve the stated objectives. Some mutagenic studies were also conducted. The environmental investigations were started in August 1978. Sengupta et al (1979a) reported the first year's efforts.

  14. Draft Genome Sequence of the Cellulolytic and Xylanolytic Thermophile Clostridium clariflavum Strain 4-2a

    PubMed Central

    Rooney, Elise A.; Rowe, Kenneth T.; Guseva, Anna; Huntemann, Marcel; Han, James K.; Chen, Amy; Kyrpides, Nikos C.; Mavromatis, Konstantinos; Markowitz, Victor M.; Palaniappan, Krishna; Ivanova, Natalia; Pati, Amrita; Liolios, Konstantinos; Nordberg, Henrik P.; Cantor, Michael N.; Hua, Susan X.; Shapiro, Nicole; Woyke, Tanja; Lynd, Lee R.

    2015-01-01

    Clostridium clariflavum strain 4-2a, a novel strain isolated from a thermophilic biocompost pile, has demonstrated an extensive capability to utilize both cellulose and hemicellulose under thermophilic anaerobic conditions. Here, we report the draft genome of this strain. PMID:26205857

  15. Thermophilic anaerobic digestion of source-sorted organic fraction of household municipal solid waste: start-up procedure for continuously stirred tank reactor.

    PubMed

    Angelidaki, Irini; Chen, Xingxing; Cui, Junbo; Kaparaju, Prasad; Ellegaard, Lars

    2006-08-01

    Two feeding strategies for start-up of continuously stirred tank reactors (CSTR) treating source-sorted organic fraction of household municipal solid waste (SS-OFMSW) at 55 degrees C were evaluated. Two reactors were started up separately with a limited amount of initial inoculum (i.e. 10% of the final volume of 3.5l) and operated in a fed batch mode until the reactors were filled (30 days). A reference reactor was filled up with 3.5l of inoculum and fed at a constant rate (11.4 g volatile solids (VS)/d). Loading at progressively increasing rate (from 1.7 to 15 gVS/d), as calculated based on an activated biomass concept, showed superior process performance compared to a fixed feed rate (5.7 gVS/d). Methane yield of 0.32 m(3)/kg VS was produced during the start-up in reactor filled at progressively increasing rate and was comparable to the reference reactor. On the contrary, significant inhibition due to volatile fatty acid (VFA) build-up, mainly due to butyrate, was noticed in the reactor filled at constant rate. Thus, low initial and progressive increasing inoculum loading rate could be used as a strategy for a successful start-up of CSTR treating SS-OFMSW as it allowed a gradual acclimation of the biomass. Lab-scale results were further reaffirmed from the start-up of a full-scale plant (7000 m(3) total capacity) which was supplied with inoculum corresponding to approx. 16% of final volume and operated in a fed batch mode until the reactors were filled (58 days). Stable biogas production with low VFA (<3 g/L; based on titration method) were noticed during the start-up period when fed at progressively increasing rate. Thus, a controlled and reliable start-up procedure was found essential, which could allow rapid process stabilization and time to focus on other technical aspects of plant operation. In addition, the influence of substrate to inoculum amount (1.5-30% TS) and temperature (5-65 degrees C) on anaerobic degradation and methane production of SS-OFMSW was

  16. Thermophilic biogasification of biomass

    SciTech Connect

    Ghosh, S.; Klass, D.L.; Edwards, V.H.; Christopher, R.W.

    1980-01-01

    Secondary sewage effluent- and fresh-water-grown water hyacinths (Eichhornia crassipes), Coastal Bermuda grass (Cynodon dactylon), and a hyacinth-grass-municipal solid waste-sludge (biomass-waste) blend were used as test feeds to develop a fast thermophilic biomass- digestion process. For the pure biomass feeds thermophilic digestion has no apparent advantage over mesophilic digestion, but the reverse is true for the biomass-waste blend. Alkaline pretreatment of the feed improved thermophilic digester performance substantially. For a given plant feed load, the reactor volume, culture-heating requirements, and CH4 production rate for thermophilic digestion of the pretreated biomass-waste feed were 18,46, and 135% of those for conventional mesophilic digestion. For a biomass-waste feed the respective volatile solids reduction and energy recovery efficiencies were 46 and 49% for thermophilic and 36 and 43% for mesophilic digestions.

  17. A Year in the Life: Annual Patterns of CO2 and CH4 from a Northern Finland Peatland, Including Anaerobic Methane Oxidation and Summer Ebullition Rates

    NASA Astrophysics Data System (ADS)

    Miller, K.; Lipson, D.; Biasi, C.; Dorodnikov, M.; Männistö, M.; Lai, C. T.

    2014-12-01

    The major ecological controls on methane (CH4) and carbon dioxide (CO2) fluxes in northern wetland systems are well known, yet estimates of source/sink magnitudes are often incongruous with measured rates. This mismatch persists because holistic flux datasets are rare, preventing 'whole picture' determinations of flux controls. To combat this, we measured net CO2 and CH4 fluxes from September 2012-2013 within a peatland in northern Lapland, Finland. In addition, we performed in situ manipulations and in vitro soil incubations to quantify anaerobic methane oxidation and methanogenic rates as they related to alternative electron acceptor availability. Average annual fluxes varied substantially between different depressions within the wetland, a pattern that persisted through all seasons. Season was a strong predictor of both CO2 and CH4 flux rates, yet CH4 rates were not related to melt-season 10cm or 30cm soil temperatures, and only poorly predicted with air temperatures. We found evidence for both autumnal and spring thaw CH4 bursts, collectively accounting for 26% of annual CH4 flux, although the autumnal burst was more than 5 fold larger than the spring burst. CH4 ebullition measured throughout the growing season augmented the CH4 source load by a factor of 1.5, and was linked with fine-scale spatial heterogeneity within the wetland. Surprisingly, CH4 flux rates were insensitive to Fe(III) and humic acid soil amendments, both of which amplified CO2 fluxes. Using in vitro incubations, we determined anaerobic methane oxidation and methanogenesis rates. Measured anaerobic oxidation rates showed potential consumption of between 6-39% of the methane produced, contributing approximately 1% of total carbon dioxide flux. Treatments of nitrate, sulfate and ferric iron showed that nitrate suppressed methanogenesis, but were not associated with anaerobic oxidation rates.

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

    PubMed

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

    2015-09-01

    In this study, batch tests were conducted to investigate the performance of mesophilic anaerobic digester sludge (ADS) at thermophilic conditions and estimate kinetic parameters for co-substrate fermentation. Starch and cellulose were used as mono-substrate and in combination as co-substrates (1:1 mass ratio) to conduct a comparative assessment between mesophilic (37 °C) and thermophilic (60 °C) biohydrogen production. Unacclimatized mesophilic ADS responded well to the temperature change. The highest hydrogen yield of 1.13 mol H2/mol hexose was observed in starch-only batches at thermophilic conditions. The thermophilic cellulose-only yield (0.42 mol H2/mol hexose) was three times the mesophilic yield (0.13 mol H2/mol hexose). Interestingly, co-fermentation of starch-cellulose at mesophilic conditions enhanced the hydrogen yield by 26% with respect to estimated mono-substrate yields, while under thermophilic conditions no enhancement in the overall yield was observed. Interestingly, the estimated overall Monod kinetic parameters showed higher rates at mesophilic than thermophilic conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Use of thermophilic biological aerobic technology for industrial waste treatment.

    PubMed

    Rozich, A F; Bordacs, K

    2002-01-01

    Thermophilic aerobic treatment systems offer unique advantages for treatment of high strength organic waste streams and slurries/sludges. These systems combine the best features of conventional aerobic and anaerobic processes that include rapid biodegradation kinetics and low biological solids production, respectively. Application of these processes can result in substantial economic benefit by reducing residuals processing and disposal costs. These systems have not been widely applied for industrial waste treatment, therefore the goal of this paper to show the advantages of applying thermophilic aerobic treatment to these streams. Also included in the paper is a discussion of the process benefits along with design/application considerations and industrial case histories.

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

    SciTech Connect

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

    1993-08-31

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

  1. Thermophilic biogasification of biomass

    SciTech Connect

    Ghosh, S.; Klass, D.L.; Christopher, R.W.; Edwards, V.H.

    1980-01-01

    Mesophilic and thermophilic digestion runs were conducted with the pure land-based biomass species, water hyacinth (Eichhornia crassipes) and Coastal Bermuda grass (Cynodon dactylon), and a blend of hyacinth, grass, MSW, and sewage sludge. A mixed biomass-waste hybrid feed was included because it has a superior nutritional balance relative to the pure feeds and it facilitates year-round operation of a biomass-to-SNG process. (7) The studies were conducted at 35/sup 0/ and 55/sup 0/C, generally believed to be optimum for mesophilic and thermophilic digestion of organic feeds. Results of mesophilic digestion were to provide baseline performance data for evaluation of thermophilic digester performance. It was decided that the feed affording the best thermophilic performance would be pretreated with dilute sodium hydroxide solution at the selected digestion temperature of 55/sup 0/C to improve methane production rate and yield. In addition, thermophilic runs were planned to investigate ways to reduce chemical requirements for alkaline pretreatment and feed slurry neutralization.

  2. Aerobic biological treatment of thermophilically digested sludge.

    PubMed

    Kevbrina, M V; Nikolaev, Y A; Danilovich, D A; Vanyushina, A Ya

    2011-01-01

    Aerobic biological treatment of digested sludge was studied in a continuously operated laboratory set-up. An aerated reactor was filled with thermophilically digested sludge from the Moscow wastewater treatment plant and inoculated with special activated sludge. It was then operated at the chemostat mode at different flow rates. Processes of nitrification and denitrification, as well as dephosphatation, occurred simultaneously during biological aerobic treatment of thermophilically digested sludge. Under optimal conditions, organic matter degradation was 9.6%, the concentrations of ammonium nitrogen and phosphate decreased by 89 and 83%, respectively, while COD decreased by 12%. Dewaterability of digested sludge improved significantly. The processes were found to depend on hydraulic retention time, oxygen regime, and temperature. The optimal conditions were as follows: hydraulic retention time 3-4 days, temperature 30-35 degrees C, dissolved oxygen levels 0.2-0.5 mg/L at continuous aeration or 0.7-1 mg/L at intermittent aeration. Based on these findings, we propose a new combined technology of wastewater sludge treatment. The technology combines two stages: anaerobic digestion followed by aerobic biological treatment of digested sludge. The proposed technology makes it possible to degrade the sludge with conversion of approximately 45% volatile suspended solids to biogas, to improve nitrogen and phosphorus removal in reject water from sludge treatment units, and to achieve removal of malodorous substances after 8-9 days of anaerobic-aerobic sludge treatment.

  3. [Conversion of acetic acid to methane by thermophiles: Progress report

    SciTech Connect

    Zinder, S.

    1991-12-31

    The objective of this project is to provide an understanding of thermophilic anaerobic microorganisms capable of breaking down acetic acid, the precursor of two-thirds of the methane produced by anaerobic bioreactors. Recent results include: (1) the isolation of Methanothrix strain CALLS-1, which grows much more rapidly than mesophilic strains; (2) the demonstration that thermophilic cultures of Methanosarcina and Methanothrix show minimum thresholds for acetate utilization of 1--2.5 mM and 10--20{mu}m respectively, in agreement with ecological data indicating that Methanothrix is favored by low acetate concentration; (3) the demonstration of high levels of thermostable acetyl-coA synthetase and carbon monoxide dehydrogenase in cell-free extracts of Methanothrix strains CALS-1; (4) the demonstration of methanogenesis from acetate and ATP in cell free extracts of strain CALS-1. (5) the demonstration that methanogenesis from acetate required 2 ATP/methane, and, in contrast to Methanosarcina, was independent of hydrogen and other electron donors; (6) the finding that entropy effects must be considered when predicting the level of hydrogen in thermophilic syntrophic cultures. (7) the isolation and characterization of the Desulfotomaculum thermoacetoxidans. Current research is centered on factors which allow thermophilic Methanothrix to compete with Methanosarcina.

  4. (Conversion of acetic acid to methane by thermophiles: Progress report)

    SciTech Connect

    Zinder, S.

    1991-01-01

    The objective of this project is to provide an understanding of thermophilic anaerobic microorganisms capable of breaking down acetic acid, the precursor of two-thirds of the methane produced by anaerobic bioreactors. Recent results include: (1) the isolation of Methanothrix strain CALLS-1, which grows much more rapidly than mesophilic strains; (2) the demonstration that thermophilic cultures of Methanosarcina and Methanothrix show minimum thresholds for acetate utilization of 1--2.5 mM and 10--20{mu}m respectively, in agreement with ecological data indicating that Methanothrix is favored by low acetate concentration; (3) the demonstration of high levels of thermostable acetyl-coA synthetase and carbon monoxide dehydrogenase in cell-free extracts of Methanothrix strains CALS-1; (4) the demonstration of methanogenesis from acetate and ATP in cell free extracts of strain CALS-1. (5) the demonstration that methanogenesis from acetate required 2 ATP/methane, and, in contrast to Methanosarcina, was independent of hydrogen and other electron donors; (6) the finding that entropy effects must be considered when predicting the level of hydrogen in thermophilic syntrophic cultures. (7) the isolation and characterization of the Desulfotomaculum thermoacetoxidans. Current research is centered on factors which allow thermophilic Methanothrix to compete with Methanosarcina.

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

    PubMed

    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 C1-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 C4 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 C1 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.

  6. [Continuous bio-hydrogen production by mesophilic and thermophilic cultures].

    PubMed

    Zhang, Wei; Zuo, Jian-E; Cui, Long-Tao; Xing, Wei; Yang, Yang

    2006-01-01

    Anaerobic biological hydrogen productions were achieved successfully in two lab-scale anaerobic hydrogen production reactors under mesophilic (37 degrees C) and thermophilic (55 degrees C) conditions, respectively. The mesophilic reactor, a CSTR, was operated over 4 months by seeding with river sediments and feeding with glucose solution, in which the highest hydrogen production rate was 8.6 L/(L x d) and the substrate hydrogen production molar ratio (H2/glucose) was 1.98. After seeded with anaerobic methanogenic granules, a UASB reactor was thermophilically operated by feeding with sucrose solution and during its steady operation period, the hydrogen production rate was 6.8 L/(L x d) and the substrate hydrogen production molar ratio (H2/sucrose) was 3.6. Within the produced gas, the H2 percentages were about 43% and others were CO2, no methane could be detected. Thermophilic hydrogen-producing granules were successfully cultivated in the UASB reactor, which were grey-white in color, the diameters were about 0.8 - 1.2 mm, and typical settling velocities were about 30 - 40 m/h. Through SEM a great number of bacilli could be found on the surface of the granules which made the surface rough. Total DNA of these two hydrogen production sludges were extracted and purified, and the PCR and DGGE process were conducted, the results indicate that most of the eubacteria in two sludges are the same, but the dominant species are obviously different with each other.

  7. Foaming phenomenon in bench-scale anaerobic digesters.

    PubMed

    Siebels, Amanda M; Long, Sharon C

    2013-04-01

    The Madison Metropolitan Sewerage District (The District) in Madison, Wisconsin has been experiencing seasonal foaming in their anaerobic biosolids digesters, which has occurred from mid-November to late June for the past few years. The exact cause(s) of foaming is unknown. Previous research findings are unclear as to whether applications of advanced anaerobic digestion processes reduce the foaming potential of digesters. The object of this study was to investigate how configurations of thermophilic and acid phase-thermophilic anaerobic digestion would affect foaming at the bench-scale level compared to single stage mesophilic digestion for The District. Bench-scale anaerobic digesters were fed with a 4 to 4.5% by dry weight of solids content blend of waste activated sludge (WAS) and primary sludge from The District. Foaming potential was monitored using Alka-Seltzer and aeration foaming tests. The bench-scale acid phase-thermophilic digester had a higher foaming potential than the bench-scale mesophilic digester. These results indicate that higher temperatures increase the foaming potential of the bench-scale anaerobic digesters. The bench-scale acid phase-thermophilic digesters had a greater percent (approximately 5 to 10%) volatile solids destruction and a greater percent (approximately 5 to 10%) total solids destruction when compared to the bench-scale mesophilic digester. Overall, for the full-scale foaming experienced by The District, it appears that adding an acid phase or switching to thermophilic digestion would not alleviate The District's foaming issues.

  8. Thermophilic microorganisms in biomining.

    PubMed

    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.

  9. Energy from anaerobic methane production. [Sweden

    SciTech Connect

    Not Available

    1982-02-01

    Since 1970 Swedish researchers have been testing the ANAMET (anaerobic-aerobic-methane) process, which involves converting industrial wastewaters via an initial anaerobic microbiological step followed by an aerobic one. Recycling the biomass material in each step allows shorter hydraulic retention times without decreasing stability or solids reduction. Since the first ANAMET plants began operating at a Swedish sugar factory in 1972, 17 more plants have started up or are under construction. Moreover, the ANAMET process has engendered to offshoot BIOMET (biomass-methane) process, a thermophilic anaerobic scheme that can handle sugar-beet pulp as well as grass and other soft, fast-growing biomasses.

  10. Biochemistry and physiology of anaerobic bacteria

    SciTech Connect

    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. Anaerobic fermentation of beef cattle manure

    NASA Astrophysics Data System (ADS)

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

    1981-01-01

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

  12. Thermophilic Beta-Glycosidase

    NASA Technical Reports Server (NTRS)

    Grogan, Dennis W.

    1992-01-01

    Report describes identification of thermophilic Beta-glycosidase enzyme from isolate of Sulfolobus solfataricus, sulfur-metabolizing archaebacteria growing aerobically and heterotrophically to relatively high cell yields. Enzyme useful in enzymatic conversion of cellulose to D-glucose and important in recycling of biomass. Used for removal of lactose from milk products. Offers promise as model substance for elucidation of basic principles of structural stabilization of proteins.

  13. Thermophilic Beta-Glycosidase

    NASA Technical Reports Server (NTRS)

    Grogan, Dennis W.

    1992-01-01

    Report describes identification of thermophilic Beta-glycosidase enzyme from isolate of Sulfolobus solfataricus, sulfur-metabolizing archaebacteria growing aerobically and heterotrophically to relatively high cell yields. Enzyme useful in enzymatic conversion of cellulose to D-glucose and important in recycling of biomass. Used for removal of lactose from milk products. Offers promise as model substance for elucidation of basic principles of structural stabilization of proteins.

  14. Thermophile bacteria in permafrost: model for astrobiology

    NASA Astrophysics Data System (ADS)

    Gilichinsky, D.; Rivkina, E.; Shcherbakova, V.; Laurinavichius, K.; Kholodov, A.; Abramov, A.

    2003-04-01

    According the NASA point of view, one way to have liquid water on Mars at shallow depths would be through subglacial volcanism. Such volcano-ice interactions could be going on beneath the polar caps of Mars today, or even within the adjacent permafrost around the margins of the ice caps. This is why one of the Earth's models, close to extraterrestrial environment, represented by active volcanoes in permafrost areas and the main question is - does such econishes as volcanoes and associated environment contain recently microbial communities? The first step of this study was carried out on volcano Stromboli (Italy), using the marine water samples extracted from the borehole near the island marine coast, surrounding the volcano. According the temperatures (45^oC), this thermal water has the hydraulic connection with volcano. Microscopy analyses of studied water shown the presence of different morphological types of microorganisms: small mobile roads, coccoid and sarcina-like organisms and long fixed roads, as well as rest forms (spores and cysts). To separate this community on marine and volcano microorganisms, the common mineral media with added CO_2, acetate or glucose-peptone as a source of carbon were used for culturing, and Fe3+, S^o, SO_42- were added as a electron acceptors. We attempt to isolate thermophilic anaerobic microorganisms of different metabolic groups - methanogens, acetogens, iron-, sulfur- and sulfate-reducers, and to test each group of microorganisms on the presence of halophilic forms. After 24 hours of incubation at temperatures varied 55 to 85^o, the grow relatively the control media was observed at CO_2+H_2 and glucose-peptone media. Microscopy study of preparations showed small coccus of irregular shape that was unable to reduce S^o or SO_42-. During the subsequent re-seeding were obtained the enrichment cultures of themophilic bacteria, genetically closed to genera Thermococcus: heterotrophic, growing up to 95^oC with the growth optimum at

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

    PubMed

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

    2008-08-15

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

  16. Volatile fatty acids productions by mesophilic and thermophilic sludge fermentation: Biological responses to fermentation temperature.

    PubMed

    Hao, Jiuxiao; Wang, Hui

    2015-01-01

    The volatile fatty acids (VFAs) productions, as well as hydrolases activities, microbial communities, and homoacetogens, of mesophilic and thermophilic sludge anaerobic fermentation were investigated to reveal the microbial responses to different fermentation temperatures. Thermophilic fermentation led to 10-fold more accumulation of VFAs compared to mesophilic fermentation. α-glucosidase and protease had much higher activities in thermophilic reactor, especially protease. Illumina sequencing manifested that raising fermentation temperature increased the abundances of Clostridiaceae, Microthrixaceae and Thermotogaceae, which could facilitate either hydrolysis or acidification. Real-time PCR analysis demonstrated that under thermophilic condition the relative abundance of homoacetogens increased in batch tests and reached higher level at stable fermentation, whereas under mesophilic condition it only increased slightly in batch tests. Therefore, higher fermentation temperature increased the activities of key hydrolases, raised the proportions of bacteria involved in hydrolysis and acidification, and promoted the relative abundance of homoacetogens, which all resulted in higher VFAs production.

  17. Balancing hygienization and anaerobic digestion of raw sewage sludge.

    PubMed

    Astals, S; Venegas, C; Peces, M; Jofre, J; Lucena, F; Mata-Alvarez, J

    2012-12-01

    The anaerobic digestion of raw sewage sludge was evaluated in terms of process efficiency and sludge hygienization. Four different scenarios were analyzed, i.e. mesophilic anaerobic digestion, thermophilic anaerobic digestion and mesophilic anaerobic digestion followed by a 60 °C or by an 80 °C hygienization treatment. Digester performance (organic matter removal, process stability and biogas yield) and the hygienization efficiency (reduction of Escherichia coli, somatic coliphages and F-specific RNA phages) were the main examined factors. Moreover, a preliminary economical feasibility study of each option was carried out throughout an energy balance (heat and electricity). The obtained results showed that both thermophilic anaerobic digestion and mesophilic anaerobic digestion followed by a hygienization step were able to produce an effluent sludge that fulfills the American and the European legislation for land application. However, higher removal efficiencies of indicators were obtained when a hygienization post-treatment was present. Regarding the energy balance, it should be noted that all scenarios have a significant energy surplus. Particularly, positive heat balances will be obtained for the thermophilic anaerobic digestion and for the mesophilic anaerobic digestion followed by 60 °C hygienization post-treatment if an additional fresh-sludge/digested sludge heat exchanger is installed for energy recovery.

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

    PubMed

    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.

  19. Complete Genome Sequence of the Cellulolytic Thermophile Clostridium thermocellum DSM1313

    SciTech Connect

    Feinberg, Lawrence F; Foden, Justine; Barrett, Trisha; Davenport, Karen W.; Bruce, David; Detter, J. Chris; Tapia, Roxanne; Han, Cliff; Lapidus, Alla L.; Lucas, Susan; Cheng, Jan-Fang; Pitluck, Sam; Woyke, Tanja; Ivanova, N; Mikhailova, Natalia; Land, Miriam L; Hauser, Loren John; Argyros, Aaron; Goodwin, Lynne A.; Hogsett, David; Caiazza, Nicky

    2011-01-01

    Clostridium thermocellum DSM1313 is a thermophilic, anaerobic bacterium with some of the highest rates of cellulose hydrolysis reported. The complete genome sequence reveals a suite of carbohydrate-active enzymes and demonstrates a level of diversity at the species level distinguishing it from the type strain ATCC27405.

  20. Complete Genome Sequence of the Cellulolytic Thermophile Caldicellulosiruptor obsidiansis OB47T

    SciTech Connect

    Elkins, James G; Lochner, Adriane; Hamilton-Brehm, Scott; Walston Davenport, Karen; Podar, Mircea; Brown, Steven D; Land, Miriam L; Hauser, Loren John; Klingeman, Dawn Marie; Raman, Babu; Goodwin, Lynne A.; Tapia, Roxanne; Meincke, Linda; Detter, J C; Bruce, David; Han, Cliff; Palumbo, Anthony Vito; Cottingham, Robert W; Keller, Martin; Graham, David E

    2010-01-01

    Caldicellulosiruptor obsidiansis OB47T (ATCC BAA-2073; JCM 16842) is an extremely thermophilic, anaerobic bacterium capable of hydrolyzing plant-derived polymers through the expression of multidomain/multifunctional hydrolases. The complete genome sequence reveals a diverse set of carbohydrate-active enzymes and provides further insight into lignocellulosic biomass hydrolysis at high temperatures.

  1. Thermophilic and hyper-thermophilic co-digestion of waste activated sludge and fat, oil and grease: Evaluating and modeling methane production.

    PubMed

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

    2016-12-01

    Renewable energy and clean environment are two crucial requirements for our modern world. Low cost, energy production and limited environmental impact make anaerobic digestion (AD) a promising technology for stabilizing organic waste and in particular, sewage waste. The anaerobic co-digestion of thickened waste activated sludge (TWAS) and sewage treatment plant trapped fat, oil and grease (FOG) using different FOG-TWAS mixtures (20, 40, 60 and 80% of FOG based on total volatile solids (TVS)) were investigated in this study using both thermophilic (55 ± 1 °C) and two stages hyper-thermophilic/thermophilic (70 ± 1 °C and 55 ± 1 °C) anaerobic co-digestion. The hyper-thermophilic co-digestion approach as a part of the co-digestion process has been shown to be very useful in improving the methane production. During hyper-thermophilic biochemical methane potential (BMP) assay testing the sample with 60% FOG (based on TVS) has been shown to significantly increase the maximum methane production to 673.1 ± 14.0 ml of methane as compared to 316.4 ± 14.3 ml of methane for the control sample. This represents a 112.7% increase in methane production compared to the control sample considered in this paper. These results signify the importance of hyper-thermophilic digestion to the co-digestion of TWAS-FOG field.

  2. Draft Genome Sequence of an Anaerobic and Extremophilic Bacterium, Caldanaerobacter yonseiensis, Isolated from a Geothermal Hot Stream

    PubMed Central

    Lee, Sang-Jae; Lee, Yong-Jik; Park, Gun-Seok; Kim, Byoung-Chan; Lee, Sang Jun; Shin, Jae-Ho

    2013-01-01

    Caldanaerobacter yonseiensis is a strictly anaerobic, thermophilic, spore-forming bacterium, which was isolated from a geothermal hot stream in Indonesia. This bacterium utilizes xylose and produces a variety of proteases. Here, we report the draft genome sequence of C. yonseiensis, which reveals insights into the pentose phosphate pathway and protein degradation metabolism in thermophilic microorganisms. PMID:24201201

  3. Continuous Thermophilic Composting12

    PubMed Central

    Schulze, K. L.

    1962-01-01

    Under complete mixing conditions, aerobic decomposition of mixed organic waste materials has been maintained continuously in the thermophilic phase in a 55-gal rotating drum. Temperatures ranged between 53 and 70 C. Raw material was added daily or every second day in amounts up to 18 lb per 100 lb of decomposing material. The weight of material removed ranged between 42 and 60% of the raw material added. Factors influencing the operation of the composting unit were studied in detail. Images FIG. 2 PMID:13909559

  4. Limnochorda pilosa gen. nov., sp. nov., a moderately thermophilic, facultatively anaerobic, pleomorphic bacterium and proposal of Limnochordaceae fam. nov., Limnochordales ord. nov. and Limnochordia classis nov. in the phylum Firmicutes.

    PubMed

    Watanabe, Miho; Kojima, Hisaya; Fukui, Manabu

    2015-08-01

    A novel facultatively anaerobic bacterium, strain HC45T, was isolated from sediment of a brackish meromictic lake in Japan, Lake Harutori. Cells were pleomorphic, and filamentous bodies were 5-100 μm in length. For growth, the optimum pH was 7.0 and the optimum temperature was 45-50 °C. The G+C content of the genomic DNA was 71 mol%. iso-C15 : 0 and anteiso-C15 : 0 were the major components in the cellular fatty acid profile. The predominant respiratory quinone was MK-7. Strain HC45T shared very low 16S rRNA gene sequence similarity with cultivated strains ( ≤ 85%). Phylogenetic analysis based on 16S rRNA gene sequences revealed that the isolate was distantly related to members of the family Symbiobacteriaceae and family XVII Incertae Sedis in the class Clostridia, and they formed a cluster separate from canonical species of the phylum Firmicutes. These results indicated that strain HC45T should not be placed in any existing class of the phylum Firmicutes. On the basis of phylogenetic and phenotypic characterization, Limnochorda pilosa gen. nov., sp. nov. is proposed with HC45T ( = NBRC 110152T = DSM 28787T) as the type strain, as the first representative of novel taxa, Limnochordales ord. nov., Limnochordaceae fam. nov. in Limnochordia classis. nov.

  5. Anaerobic bacteria

    MedlinePlus

    Anaerobic bacteria are bacteria that do not live or grow when oxygen is present. In humans, these bacteria ... Goldstein EJ. Diseases caused by non-spore forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman's Cecil ...

  6. DNA replication in thermophiles.

    PubMed

    Majerník, A I; Jenkinson, E R; Chong, J P J

    2004-04-01

    DNA replication enzymes in the thermophilic Archaea have previously attracted attention due to their obvious use in methods such as PCR. The proofreading ability of the Pyrococcus furiosus DNA polymerase has resulted in a commercially successful product (Pfu polymerase). One of the many notable features of the Archaea is the fact that their DNA processing enzymes appear on the whole to be more like those found in eukaryotes than bacteria. These proteins also appear to be simpler versions of those found in eukaryotes. For these reasons, archaeal organisms make potentially interesting model systems to explore the molecular mechanisms of processes such as DNA replication, repair and recombination. Why archaeal DNA-manipulation systems were adopted over bacterial systems by eukaryotic cells remains a most interesting question that we suggest may be linked to thermophily.

  7. Thermophilic molds: Biology and applications.

    PubMed

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

    2016-11-01

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

  8. Processing anaerobic sludge for extended storage as anaerobic digester inoculum.

    PubMed

    Li, Jiajia; Zicari, Steven M; Cui, Zongjun; Zhang, Ruihong

    2014-08-01

    Thermophilic anaerobic sludge was processed to reduce the volume and moisture content in order to reduce costs for storing and transporting the sludge as microbial inoculum for anaerobic digester startup. The moisture content of the sludge was reduced from 98.7% to 82.0% via centrifugation and further to 71.5% via vacuum evaporation. The processed sludge was stored for 2 and 4 months and compared with the fresh sludge for the biogas and methane production using food waste and non-fat dry milk as substrates. It was found that fresh unprocessed sludge had the highest methane yield and the yields of both unprocessed and processed sludges decreased during storage by 1-34%, however processed sludges seemed to regain some activity after 4 months of storage as compared to samples stored for only 2 months. Maximum methane production rates obtained from modified Gompertz model application also increased between the 2-month and 4-month processed samples.

  9. Tolerance of thermophilic and hyperthermophilic microorganisms to desiccation.

    PubMed

    Beblo, Kristina; Rabbow, Elke; Rachel, Reinhard; Huber, Harald; Rettberg, Petra

    2009-05-01

    We examined short- and long-term desiccation tolerance of 31 strains of thermophilic and hyperthermophilic Archaea and thermophilic phylogenetically deep-branching Bacteria. Seventeen organisms showed a significant high ability to withstand desiccation. The desiccation tolerance turned out to be species-specific and was influenced by several parameters such as storage temperature, pH, substrate or presence of oxygen. All organisms showed a higher survival rate at low storage temperatures (-20 degrees C or below) than at room temperature. Anaerobic and microaerophilic strains are influenced negatively in their survival by the presence of oxygen during desiccation and storage. The desiccation tolerance of Sulfolobales strains is co-influenced by the pH and the substrate of the pre-culture. The distribution of desiccation tolerance in the phylogenetic tree of life is not domain specific. Surprisingly, there are dramatic differences in desiccation tolerance among organisms from the same order and even from closely related strains of the same genus. Our results show that tolerance of vegetative cells to desiccation is a common phenomenon of thermophilic and hyperthermophilic microorganisms although they originated from quite different non-arid habitats like boiling acidic springs or black smoker chimneys.

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

    PubMed

    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.

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

    PubMed Central

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

    NASA Astrophysics Data System (ADS)

    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.

  13. Anaerobic digestion of solid waste: state-of-the-art.

    PubMed

    De Baere, L

    2000-01-01

    In order to make a correct assessment of the state-of-the-art of the technology, a study was made on the development of digestion capacity for solid waste in Europe. The study was limited to plants in operation or under construction that were treating at least 10% organic solid waste coming from market waste or municipal solid waste. A total treatment capacity for solid waste organics, excluding the tonnage used for sewage sludge and manures, evolved from 122,000 ton per year in 1990 to 1,037,000 ton available or under construction by the year 2000 in 53 plants across Europe, an increase by 750%. Both mesophilic and thermophilic technologies have been proven, with about 62% of capacity being operated at mesophilic temperatures. Wet and dry digestion are almost evenly split, while a clear choice was made for one-phase systems instead of two-phase systems, which represent only 10.6% of capacity. The capacity provided by co-digestion systems is limited, while there is a rising interest in digestion of mixed household waste. The reliable performance has been demonstrated for all types of anaerobic digestion systems. On the basis of the Dranco technology, a single-phase thermophilic dry digestion process, performances were reached similar to high-rate wastewater digestion. An annual average loading rate of 18.5 kg COD/m3.day, resulting in a biogas production of 9.2 m3/m3 reactor.day was obtained at a full-scale plant. The plant operated at a retention time of 15.3 days. Feedstocks range from clean organic wastes (31% dry matter) to heavily polluted grey waste organics (57% dry matter). Average dry matter concentrations of the digested residue of 41% were obtained.

  14. Anaerobic Infections

    MedlinePlus

    ... doses of antibiotics taken by mouth for months. Bacteroides and Prevotella infections. Bacterial organisms from species called Bacteroides and Prevotella are anaerobic. They are common organisms ...

  15. Were the original eubacteria thermophiles?

    NASA Technical Reports Server (NTRS)

    Achenbach-Richter, L.; Gupta, R.; Stetter, K. O.; Woese, C. R.; Johnson, P. C. (Principal Investigator)

    1987-01-01

    Thermotoga maritima is one of the more unusual eubacteria: It is highly thermophilic, growing at temperatures higher than any other eubacterium; its cell wall appears to have a unique structure and its lipids a unique composition; and the organism is surrounded by a loose-fitting sheath of unknown function. Its phenotypic uniqueness is matched by its phylogenetic position; Thermotoga maritima represents the deepest known branching in the eubacterial line of descent, as measured by ribosomal RNA sequence comparisons. T. maritima also represents the most slowly evolving of eubacterial lineages. The fact that the two deepest branchings in the eubacterial line of descent (the other, the green non-sulfur bacteria and relatives, i.e. Chloroflexus, Thermomicrobium, etc.) are both basically thermophilic and slowly evolving, strongly suggests that all eubacteria have ultimately arisen from a thermophilic ancestor.

  16. Were the original eubacteria thermophiles?

    NASA Technical Reports Server (NTRS)

    Achenbach-Richter, L.; Gupta, R.; Stetter, K. O.; Woese, C. R.; Johnson, P. C. (Principal Investigator)

    1987-01-01

    Thermotoga maritima is one of the more unusual eubacteria: It is highly thermophilic, growing at temperatures higher than any other eubacterium; its cell wall appears to have a unique structure and its lipids a unique composition; and the organism is surrounded by a loose-fitting sheath of unknown function. Its phenotypic uniqueness is matched by its phylogenetic position; Thermotoga maritima represents the deepest known branching in the eubacterial line of descent, as measured by ribosomal RNA sequence comparisons. T. maritima also represents the most slowly evolving of eubacterial lineages. The fact that the two deepest branchings in the eubacterial line of descent (the other, the green non-sulfur bacteria and relatives, i.e. Chloroflexus, Thermomicrobium, etc.) are both basically thermophilic and slowly evolving, strongly suggests that all eubacteria have ultimately arisen from a thermophilic ancestor.

  17. Influence of Thermal and Bacterial Pretreatment of Microalgae on Biogas Production in Mesophilic and Thermophilic Conditions.

    PubMed

    Vidmar, Beti; Marinšek Logar, Romana; Panjičko, Mario; Fanedl, Lijana

    2017-01-01

    Microalgae biomass has a great potential in search for new alternative energy sources. They can be used as a substrate for the biogas production in anaerobic digestion. When using microalgae, the efficiency of this process is hampered due to the resistant cell wall. In order to accelerate the hydrolysis of cell wall and increase the efficiency of biogas production we applied two different pretreatments - biological and thermal under mesophilic and thermophilic conditions. During biological pretreatment we incubated microalgae with anaerobic hydrolytic bacteria Pseudobutyrivibrio xylanivorans Mz5T. In thermal pretreatment we incubated microalgae at 90 °C. We also tested a combined thermal and biological pretreatment in which we incubated P. xylanivorans Mz5T with thermally pretreated microalgae. Thermal pretreatment in mesophilic and thermophilic process has increased methane production by 21% and 6%, respectively. Biological pretreatment of microalgae has increased methane production by 13%, but only under thermophilic conditions (pretreatment under mesophilic conditions showed no effect on methane production). Thermal-biological pretreatment increased methane production by 12% under thermophilic conditions and by 6% under mesophilic conditions.

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

    PubMed

    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.

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

    PubMed Central

    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

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

    PubMed

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

    2015-01-01

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

  1. Complete Genome Sequence of the Thermophilic, Piezophilic, Heterotrophic Bacterium Marinitoga piezophila KA3

    SciTech Connect

    Lucas, Susan; Han, James; Lapidus, Alla L.; Cheng, Jan-Fang; Goodwin, Lynne A.; Pitluck, Sam; Peters, Lin; Mikhailova, Natalia; Teshima, Hazuki; Detter, J. Chris; Han, Cliff; Tapia, Roxanne; Land, Miriam L; Hauser, Loren John; Kyrpides, Nikos C; Ivanova, N; Pagani, Ioanna; Vannier, Pauline; Oger, Phil; Bartlett, Douglas; Noll, Kenneth M; Woyke, Tanja; Jebbar, Mohamed

    2012-01-01

    Marinitoga piezophila KA3 is a thermophilic, anaerobic, chemoorganotrophic, sulfur-reducing bacterium isolated from the Grandbonum deep-sea hydrothermal vent site at the East Pacific Rise (13 degrees N, 2,630-m depth). The genome of M. piezophila KA3 comprises a 2,231,407-bp circular chromosome and a 13,386-bp circular plasmid. This genome was sequenced within Department of Energy Joint Genome Institute CSP 2010.

  2. Microbial influenced corrosion by thermophilic bacteria

    NASA Astrophysics Data System (ADS)

    Lata, Suman; Sharma, Chhaya; Singh, Ajay

    2012-03-01

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

  3. Toxigenic Thermophilic and Thermotolerant Fungi

    PubMed Central

    Davis, N. D.; Wagener, R. E.; Morgan-Jones, G.; Diener, U.L.

    1975-01-01

    Twenty-three isolates of fungi, representing 13 thermophilic and thermotolerant species, were bioassayed for toxigenicity to brine shrimp, chicken embryos, and rats. Thirteen isolates representing nine genera were highly toxic to at least two of the three systems. Seven additional isolates of five genera were slightly toxic. PMID:1092262

  4. Microbial Ecology of Thermophilic Anaerobic Digestion. Final Report

    DOE R&D Accomplishments Database

    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.

  5. Microbial ecology of thermophilic anaerobic digestion. Final report

    SciTech Connect

    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.

  6. Thermophiles Microbe Signature in Lake Vostok, Antarctica

    NASA Astrophysics Data System (ADS)

    Bulat, S. A.; Alekhina, I. A.; Blot, M.; Petit, J.; Waggenbach, D.; Lipenkov, V. Y.; Raynaud, D.; Lukin, V. V.

    2002-05-01

    Molecular biology studies by PCR-based analyses of 16S rDNA in Vostok ice showed that glacier ice, accreted ice and thus likely the lake water itself are incredibly pure in regard to microbes. Very low DOC (Dissolved Organic Carbon) content is at range 0.0-24.7 ppb in accreted and glacier ice along, suggesting together with the DNA content for an autotrophic rather than heterotrophic life in the lake. The bacterial biomass in both accreted and glacier ice is expected to be less than 10 to 50 cells/mL of meltwater, a value close to detection limits of PCR (Polymerase Chain Reaction) implemented (2-8 cells/mL). In addition, prospect for glacier-released microbes to be active in the lake seems to be rather questionable due to possible DNA degradation through oxidation within oxygen-rich glacier ice during its long (1000 kyr) transit from the surface to the base of the ice sheet. This may explain our failure with confident microbial DNA findings in glacier ice. The glacier-released microbes that may be alive or decayed would represent a very low input to lake biota and to DOC content. Also, the postulated excess of oxygen released into the lake by glacier melting is unlikely to be consumed much microbiologically. By comparing glacier and accreted ice cores facilitated by analysis the external (contaminated) part of the iced cores vs. the internal uncontaminated region from accreted ice samples, we detected so far three bacteria as clone assortment that are believed indigenous in the lake Vostok. They all by closely related database DNA signatures represent (expected to be) thermophiles. One of them is known extant species identified in hot springs and capable to grow as a chemolithoautotroph oxidizing H2 and reducing CO2 at reduced O2 tensions. Two other taxa are not identified in the current databases, but showed relatedness to bacteria associated to hydrothermal vents and surface sediments nearby. Among them are thiosulfate-oxidizers and anaerobic methanotrophs (96

  7. Anaerobic digestion of aliphatic polyesters.

    PubMed

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

    2016-01-01

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

  8. Anaerobic bioprocessing of organic wastes.

    PubMed

    Verstraete, W; de Beer, D; Pena, M; Lettinga, G; Lens, P

    1996-05-01

    continuously stirred tank system to the thermophilic configuration, as the latter permits higher conversion rates and easier sanitation. Integration of ultrafiltration in anaerobic slurry digestion facilitates operation at higher volumetric loading rates and at shorter residence times. With respect to organic solids, the recent trend in society towards source separated collection of biowaste has opened a broad range of new application areas for solid state anaerobic fermentation.

  9. Thermophilic microbes in ethanol production

    SciTech Connect

    Slapack, G.E.; Russell, I.; Stewart, G.G.

    1987-01-01

    General and specific properties of thermophilic ethanol-producing bacteria are reviewed and their relative merits in ethanol production assessed. The studies examine the use of bacteria in mono- and co-culture fermentations for ethanol production from cellulosics; in particular, the cellulase system of Clostridium thermocellum is considered. Thermotolerant yeasts and physiological factors influencing their growth and fermentation at high temperatures are discussed. Emphasis is placed on multidisciplinary approaches to develop economical processes for ethanol production at high temperatures. Relevant topics considered include: adaptation, nutrition, heat shock, ethanol tolerance, metabolic control, genetic improvement, and fermentation/process design. General aspects of thermophily for both bacteria and yeasts (definitions, ecological aspects, merits and limitations, other industrial uses, thermostability of cellular components, and consequences of thermophilic fermentation) are discussed and the volume references over 1100 relevant articles.

  10. Stress response physiology of thermophiles.

    PubMed

    Ranawat, Preeti; Rawat, Seema

    2017-04-01

    Thermo (or hyperthermo) philic microorganisms are ubiquitous having a wide range of habitats from freshly fallen snow to pasteurized milk to geothermal areas like hot springs. The variations in physicochemical conditions, viz., temperature, pH, nutrient availability and light intensity in the habitats always pose stress conditions for the inhabitants leading to slow growth or cell death. The industrial processes used for harvesting secondary metabolites such as enzymes, toxins and organic acids also create stressed environments for thermophiles. The production of DNA-binding proteins, activation of reactive oxygen species detoxification system, compatible solute accumulation, expression of heat shock proteins and alterations in morphology are a few examples of physiological changes demonstrated by these microscopic lifeforms in stress. These microorganisms exhibit complex genetic and physiological changes to minimize, adapt to and repair damage caused by extreme environmental disturbances. These changes are termed as 'stress responses' which enable them to stabilize their homeostasis. The exploration of important thermophilic factors would pave the way in engineering the microbial strains for various biotechnological applications. This review article presents a picture of physiological responses of thermophiles against various stress conditions as their mechanisms to respond to stress make them model organisms to further explore them for basic and applied biology purposes.

  11. Hemicellulose conversion by anaerobic digestion

    SciTech Connect

    Ghosh, S.; Henry, M.P.; Christopher, R.W.

    1982-01-01

    The digestibility of an aquatic biomass (water hyacinth), a land-based biomass (Coastal Bermuda grass), and a biomass-waste blend (a mixture of hyacinth, grass, MSW, and sludge) under various digestion conditions was studied. Anaerobic digestion of hemicellulose consists of the steps of enzymatic hydrolysis of hemicellulose to glucans, mannans, galactans, xylans, and arabans, and then to simple hexose and pentose sugars; production of C/sub 2/ and higher fatty acids from the simple sugars; conversion of higher fatty acids to acetate; and finally, production of methane and CO/sub 2/ from acetate, and CO/sub 2/ and hydrogen. The conversion of hemicellulose was higher under mesophilic conditions than those of cellulose or protein for all biomass test feeds, probably because the hemicellulose structure was more vulnerable to enzymatic attack than that of the lignocellulosic component. Cellulose conversion efficiencies at the mesophilic and thermophilic temperatures were about the same. However, hemicellulose was converted at a much lower efficiency than cellulose during thermophilic digestion - a situation that was the reverse of that observed at the mesophilic temperature. Cellulose was utilized in preference to hemicellulose during mesophilic digestion of nitrogen-supplemented Bermuda grass. It was speculated that Bermuda grass cellulose was converted at a higher efficiency than hemicellulose in the presence of external nitrogen because the metabolism of the breakdown product (glucose) of cellulose requires the least investment of enzymes and energy.

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

    PubMed

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

    2011-03-01

    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 89 ml-H(2)/g-VS (190 ml-H(2)/g-sugars) and 307 ml-CH(4)/g-VS, respectively were achieved simultaneously with the overall VS removal efficiency of 81% by operating with total hydraulic retention time (HRT) of 4 days . The energy conversion efficiency was dramatically increased from only 7.5% in the hydrogen stage to 87.5% of the potential energy from hydrolysate, corresponding to total energy of 13.4 kJ/g-VS. Dominant hydrogen-producing bacteria in the H(2)-UASB reactor were Thermoanaerobacter wiegelii, Caldanaerobacter subteraneus, and Caloramator fervidus. Meanwhile, the CH(4)-UASB reactor was dominated with methanogens of Methanosarcina mazei and Methanothermobacter defluvii. The results from this study suggest the two stage anaerobic process can be effectively used for energy recovery and for stabilization of hydrolysate at anaerobic conditions.

  13. First draft genome sequence of the amylolytic Bacillus thermoamylovorans wild-type strain 1A1 isolated from a thermophilic biogas plant.

    PubMed

    Koeck, Daniela E; Wibberg, Daniel; Maus, Irena; Winkler, Anika; Albersmeier, Andreas; Zverlov, Vladimir V; Pühler, Alfred; Schwarz, Wolfgang H; Liebl, Wolfgang; Schlüter, Andreas

    2014-12-20

    The moderately thermophilic, anaerobic bacterium Bacillus thermoamylovorans 1A1 (DSM 29353) was isolated from a biogas plant in Germany. It is able to grow efficiently on various carbohydrates such as starch, pectin or xylan. The draft genome sequence of B. thermoamylovorans 1A1 was established and provides the genetic basis for application of this microorganism in degradation of plant biomass.

  14. Identity, Abundance, and Reactivation Kinetics of Thermophilic Fermentative Endospores in Cold Marine Sediment and Seawater

    PubMed Central

    Volpi, Marta; Lomstein, Bente Aa.; Sichert, Andreas; Røy, Hans; Jørgensen, Bo B.; Kjeldsen, Kasper U.

    2017-01-01

    Cold marine sediments harbor endospores of fermentative and sulfate-reducing, thermophilic bacteria. These dormant populations of endospores are believed to accumulate in the seabed via passive dispersal by ocean currents followed by sedimentation from the water column. However, the magnitude of this process is poorly understood because the endospores present in seawater were so far not identified, and only the abundance of thermophilic sulfate-reducing endospores in the seabed has been quantified. We investigated the distribution of thermophilic fermentative endospores (TFEs) in water column and sediment of Aarhus Bay, Denmark, to test the role of suspended dispersal and determine the rate of endospore deposition and the endospore abundance in the sediment. We furthermore aimed to determine the time course of reactivation of the germinating TFEs. TFEs were induced to germinate and grow by incubating pasteurized sediment and water samples anaerobically at 50°C. We observed a sudden release of the endospore component dipicolinic acid immediately upon incubation suggesting fast endospore reactivation in response to heating. Volatile fatty acids (VFAs) and H2 began to accumulate exponentially after 3.5 h of incubation showing that reactivation was followed by a short phase of outgrowth before germinated cells began to divide. Thermophilic fermenters were mainly present in the sediment as endospores because the rate of VFA accumulation was identical in pasteurized and non-pasteurized samples. Germinating TFEs were identified taxonomically by reverse transcription, PCR amplification and sequencing of 16S rRNA. The water column and sediment shared the same phylotypes, thereby confirming the potential for seawater dispersal. The abundance of TFEs was estimated by most probable number enumeration, rates of VFA production, and released amounts of dipicolinic acid during germination. The surface sediment contained ∼105–106 inducible TFEs cm-3. TFEs thus outnumber

  15. Identity, Abundance, and Reactivation Kinetics of Thermophilic Fermentative Endospores in Cold Marine Sediment and Seawater.

    PubMed

    Volpi, Marta; Lomstein, Bente Aa; Sichert, Andreas; Røy, Hans; Jørgensen, Bo B; Kjeldsen, Kasper U

    2017-01-01

    Cold marine sediments harbor endospores of fermentative and sulfate-reducing, thermophilic bacteria. These dormant populations of endospores are believed to accumulate in the seabed via passive dispersal by ocean currents followed by sedimentation from the water column. However, the magnitude of this process is poorly understood because the endospores present in seawater were so far not identified, and only the abundance of thermophilic sulfate-reducing endospores in the seabed has been quantified. We investigated the distribution of thermophilic fermentative endospores (TFEs) in water column and sediment of Aarhus Bay, Denmark, to test the role of suspended dispersal and determine the rate of endospore deposition and the endospore abundance in the sediment. We furthermore aimed to determine the time course of reactivation of the germinating TFEs. TFEs were induced to germinate and grow by incubating pasteurized sediment and water samples anaerobically at 50°C. We observed a sudden release of the endospore component dipicolinic acid immediately upon incubation suggesting fast endospore reactivation in response to heating. Volatile fatty acids (VFAs) and H2 began to accumulate exponentially after 3.5 h of incubation showing that reactivation was followed by a short phase of outgrowth before germinated cells began to divide. Thermophilic fermenters were mainly present in the sediment as endospores because the rate of VFA accumulation was identical in pasteurized and non-pasteurized samples. Germinating TFEs were identified taxonomically by reverse transcription, PCR amplification and sequencing of 16S rRNA. The water column and sediment shared the same phylotypes, thereby confirming the potential for seawater dispersal. The abundance of TFEs was estimated by most probable number enumeration, rates of VFA production, and released amounts of dipicolinic acid during germination. The surface sediment contained ∼10(5)-10(6) inducible TFEs cm(-3). TFEs thus outnumber

  16. Mechanisms, chemistry and kinetics of the anaerobic biodegradation of cis-dichloroethylene and vinyl chloride. First annual progress report, September 15, 1996--September 14, 1997

    SciTech Connect

    McCarty, P.L.; Spormann, A.

    1997-01-01

    'This three-year project is to study the anaerobic biological conversion of cis-1,2- dichloroethene (cDCE) and vinyl Chloride (VC) to ethene. The study is being conducted in three separate phases, the first to better understand the mechanisms involved in cDCE and VC biodegradation, the second to evaluate the chemistry of the processes involved, and the third, to study factors affecting reaction kinetics. Major funding is being provided by the US Department of Energy, but the DuPont Chemical Company has also agreed to directly cost-share on the project at a rate of $75,000 per year for the three year period. Tetrachloroethylene (PCE) and trichloroethylene (TCE) are solvents that are among the most widely occurring organic groundwater contaminants. The biological anaerobic reduction-of chlorinated aliphatic hydrocarbons (CAHs) such as PCE and TCE to cDCE and VC in groundwater was reported in the early 1980s. Further reduction of PCE and its intermediates to ethene was reported in 1989. Several pure cultures of anaerobic bacteria have been found to reductively dehalogenate PCE to cDCE Rates of reduction of PCE and TCE to cDCE are high and the need for electron donor addition for the reactions is small. However, the subsequent reduction of cDCE to VC, and then of VC to the harmless end product, ethene, is much slower and only recently has a pure culture been reported that is capable of reducing cDCE to VC or VC to ethene. There are numerous. reports of such conversions in mixed cultures. The reduction of cDCE and VC to ethene is where basic research is most needed and is the subject of this study.'

  17. Improvement of anaerobic digestion of sludge.

    PubMed

    Dohányos, M; Zábranská, J; Kutil, J; Jenícek, P

    2004-01-01

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

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

    SciTech Connect

    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.

  19. The hemicellulases from the ethanologenic thermophile: Themoanaerobacter ethanolius

    SciTech Connect

    Wiegel, J.

    1991-05-01

    Previously, we had only obtained extremely low xylanase activity in cultures of {ital Thermoanaerobacter ethanolicus} strain JW200, despite demonstrated xylan hydrolysis. We were not able to increase the enzyme activity or concentrate it in solution. Therefore, we decided to isolate new strains of thermophilic anaerobes with higher xylanase activity as a future source for cloning xylanases into {ital T. ethanolicus}. We now have organisms exhibiting 100-fold higher xylanase activity than JW200, but still cannot isolate or concentrate the enzyme activity except at very low yields. We have concentrated and partially purified a xylanase from strain N.D. using preparative matrix-free isoelectric focusing. We have also purified to homogeneity and partially characterized a xylosidase from {ital T. ethanolicus}. We have detected and measured arabinosidase and acetyl esterase activity in {ital T.ethanolicus}, {ital Clostridium thermohydrosulfuricum} and strain N.D. 7 refs., 2 tabs. (MHB)

  20. Biocorrosive thermophilic microbial communities in Alaskan North Slope oil facilities.

    PubMed

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

    2009-10-15

    Corrosion of metallic oilfield pipelines by microorganisms is a costly but poorly understood phenomenon, with standard treatment methods targeting mesophilic sulfate-reducing bacteria. In assessing biocorrosion potential at an Alaskan North Slope oil field, we identified thermophilic hydrogen-using methanogens, syntrophic bacteria, peptide- and 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 reinjected into reservoirs for oil recovery purposes, are biodegraded and can provide biocorrosive microbial communities with an important source of nutrients.

  1. A thermophilic gram-negative nitrate-reducing bacterium, Calditerrivibrio nitroreducens, exhibiting electricity generation capability.

    PubMed

    Fu, Qian; Kobayashi, Hajime; Kawaguchi, Hideo; Wakayama, Tatsuki; Maeda, Haruo; Sato, Kozo

    2013-01-01

    To exploit the potential diversity of thermophilic exoelectrogens, two-chamber microbial fuel cells (MFCs) were inoculated with thermophilic anaerobic digester sludge and operated at 55 °C without supplementing with exogenous redox mediator. The MFC generated a maximum power density of 823 mW m(-2) after 200 h of operation. Molecular phylogenetic analyses suggested that the microbial population on the anode was dominated by a species closely related to a thermophilic nitrate-reducing bacterium Calditerrivibrio nitroreducens, for which a strain (Yu37-1) has been isolated in pure culture. Thus, a pure culture of the C. nitroreducens strain Yu37-1 was inoculated into MFC to examine the electricity generation capability. Without an exogenous mediator, MFCs stably produced electricity with a maximum power density of 272 mW m(-2) for >400 h of operation. The MFC current recovered to the original level within few hours after medium replacement, suggesting that the electricity generation was caused by the anodic microorganisms. Cyclic voltammetry indicated that redox systems (E3 and Ec) with similar potentials (-0.14 and -0.17 V) made the main contributions to the exoelectrogenic activities of the sludge-derived consortium and C. nitroreducens Yu37-1, respectively. This study undertook the bioelectrochemical characterization of C. nitroreducens as the first example of a thermophilic Gram-negative exoelectrogen.

  2. [Thermophiles and life science in space].

    PubMed

    Yamagishi, A

    2000-12-01

    Thermophiles are microorganisms that can grow at temperatures higher than 50 or 60 degrees C. There are thermophilic eubacteria and thermophilic archaebacteria. Thermophilic microorganisms can be found geothermally and hydrothermally active area. The water penetrates into deep subsurface around thermal area and reacts with hot basalt. Some of the compounds in the water are reduced by the reaction. The water returned to the surface and reacts with seawater or air, depending on the location of the thermal area. Many types of autotrophes and heterotrophes were found near thermally active area. The microorganisms form the ecosystem based on the redox chemical reactions. All of the structural elements in thermophilic microorganisms are thermophilic or thermostable. Proteins found in microorganisms are thermostable. Though several common characteristics can be found in thermostable proteins, it is not easy to attribute the stability to specific amino acid residues. DNA in thermophiles is stabilized by increasing the G+C content or by histone-like DNA binding proteins. There are several molecular biological and geological evidences to support the relation between ancient life forms and thermal activity on the Earth. Thermophiles of different life forms may be found in thermally active area, in such as those that may be present in satellites of Jupiter.

  3. Pressure Stabilization of Proteins from Extreme Thermophiles

    PubMed Central

    Hei, Derek J.; Clark, Douglas S.

    1994-01-01

    We describe the stabilization by pressure of enzymes, including a hydrogenase from Methanococcus jannaschii, an extremely thermophilic deep-sea methanogen. This is the first published report of proteins from thermophiles being stabilized by pressure. Inactivation studies of partially purified hydrogenases from an extreme thermophile (Methanococcus igneus), a moderate thermophile (Methanococcus thermolithotrophicus), and a mesophile (Methanococcus maripaludis), all from shallow marine sites, show that pressure stabilization is not unique to enzymes isolated from high-pressure environments. These studies suggest that pressure stabilization of an enzyme may be related to its thermophilicity. Further experiments comparing the effects of increased pressure on the stability of α-glucosidases from the hyperthermophile Pyrococcus furiosus and Saccharomyces cerevisiae support this possibility. We have also examined pressure effects on several highly homologous glyceraldehyde-3-phosphate dehydrogenases from mesophilic and thermophilic sources and a rubredoxin from P. furiosus. The results suggest that hydrophobic interactions, which have been implicated in the stabilization of many thermophilic proteins, contribute to the pressure stabilization of enzymes from thermophiles. PMID:16349220

  4. Thermo- and mesophilic anaerobic digestion of wheat straw by the upflow anaerobic solid-state (UASS) process.

    PubMed

    Pohl, Marcel; Mumme, Jan; Heeg, Kathrin; Nettmann, Edith

    2012-11-01

    In this experimental work, the feasibility of wheat straw as a feedstock for biogas production is investigated using the newly developed upflow anaerobic solid-state (UASS) process. With the analytical emphasis placed on methane and metabolite production, both mesophilic and thermophilic 39 L UASS reactors were operated for 218 days at an organic loading rate of 2.5 g(VS)L(-1)d(-1) using wheat straw as sole substrate. For improved methanization of soluble metabolites, each UASS reactor was connected to an individual 30 L anaerobic filter (AF). During steady state thermophilic straw digestion was found to have a 36% higher methane yield (0.165 L g(VS)(-1)) whereas the hydrolysis rate constant increased by 106% (0.066 d(-1)).

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

    PubMed

    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.

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

    PubMed

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

    2016-01-01

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

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

    PubMed

    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. Diversity of thermophilic populations during thermophilic aerobic digestion of potato peel slurry.

    PubMed

    Ugwuanyi, J O; Harvey, L M; McNeil, B

    2008-01-01

    To study the diversity of thermophiles during thermophilic aerobic digestion (TAD) of agro-food waste slurries under conditions similar to full-scale processes. Population diversity and development in TAD were studied by standard microbiological techniques and the processes monitored by standard fermentation procedures. Facultative thermophiles were identified as Bacillus coagulans and B. licheniformis, while obligate thermophiles were identified as B. stearothermophilus. They developed rapidly to peaks of 10(7) to 10(8) in thermophiles increased with process temperatures. Thermophiles were unstable at process pH above or below neutral, but developed rapidly at all aeration rates. Peak populations were higher in the median than at extremes of aeration rates. Obligate thermophiles were unstable at low aeration rates. Process self-heating was higher at lower than at higher aeration rate. Beyond 96 h most thermophiles were present as spores. Limited range of indigenous thermophiles drives TAD of slurry. They develop rapidly and are stable at most digestion conditions. Development and stability of thermophiles in TAD suggest that the process may be operated in a wide range of conditions; and even at short HRT in continuous processes without compromising efficiency.

  9. Reduction and immobilization of radionuclides and toxic metal ions using combined zero valent iron and anaerobic bacteria. 1998 annual progress report

    SciTech Connect

    Weathers, L.

    1998-06-01

    'Previous research findings indicate that both zero valent iron and sulfate reducing bacteria (SRB) can yield significant decreases in Cr(VI) or U(VI) concentrations due to abiotic and microbial reduction, respectively. The major hypothesis associated with this research project is that a combined abiotic-biological system can synergistically combine both processes to maximize metal ion reduction in an engineered permeable reactive barrier. The overall goal of this project is to design a combined abiotic/microbial, reactive, permeable, in-situ barrier with sufficient reductive potential to prevent downgradient migration of toxic metal ions. The field-scale application of this technology would utilize anaerobic digester sludge, Fe(O) particles for supporting anaerobic biofilms, and suitable aquifer material for construction of the barrier. Successful completion of this goal requires testing of the two hypotheses listed above by evaluating: (1) the rates of abiotic metal ion reduction, and (2) the rates of microbial metal ion reduction in microbial and combined abiotic/microbial reduction systems under a range of environmental conditions. This report summarizes work after one and one-half years of a three year project. Abiotic studies: The thrust of the abiotic research conducted to date has been to determine the rates of Cr(VI) reduction in batch reactors and to evaluate the role of aquifer materials on those rates. Experiments have been conducted to determine the rates of reduction by Fe(II) and Fe(O). The parameters that have been evaluated are the effect of pH and the presence of sulfide and aquifer material.'

  10. Finding extraterrestrial sites for thermophiles.

    PubMed

    Naylor, T

    2004-04-01

    Virtually our entire knowledge of the universe comes from two sorts of measurement of the electromagnetic radiation from the stars and galaxies within it; either their flux through relatively wide bandpasses (photometry), or measurements of the shape and wavelength of relatively narrow lines via spectroscopy. These techniques are now being used to discover planets outside our solar system, and perhaps in the next 10 years will begin to characterize them. If a serious search is to be made for extraterrestrial thermophiles, we need predictions for the effects of thermophiles on their host planets that are observable with these techniques. In this paper I shall outline what sorts of observation are likely to be used in the next 15 years for extra-solar planet work. All of the journal articles quoted here can be found through http://adsabs.harvard.edu/abstract_service.html, and often also accessed as preprints at http://uk.arxiv.org/form/astro%20ph?MULTI=form%20+/-%20interface.

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

    PubMed

    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.

  12. Extremely thermophilic energy metabolisms: biotechnological prospects.

    PubMed

    Straub, Christopher T; Zeldes, Benjamin M; Schut, Gerrit J; Adams, Michael Ww; Kelly, Robert M

    2017-03-16

    New strategies for metabolic engineering of extremely thermophilic microorganisms to produce bio-based fuels and chemicals could leverage pathways and physiological features resident in extreme thermophiles for improved outcomes. Furthermore, very recent advances in genetic tools for these microorganisms make it possible for them to serve as metabolic engineering hosts. Beyond providing a higher temperature alternative to mesophilic platforms, exploitation of strategic metabolic characteristics of high temperature microorganisms grants new opportunities for biotechnological products. This review considers recent developments in extreme thermophile biology as they relate to new horizons for energy biotechnology.

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

    PubMed Central

    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 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. PMID:23209374

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

    PubMed

    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.

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

    PubMed

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

    2015-11-20

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed Central

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

    2015-01-01

    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 LIND6LT2T. 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. PMID:26590273

  18. Early Microbial Evolution: The Age of Anaerobes.

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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

  20. Consolidated bioprocessing method using thermophilic microorganisms

    DOEpatents

    Mielenz, Jonathan Richard

    2016-02-02

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

  1. Industrial relevance of thermophilic Archaea.

    PubMed

    Egorova, Ksenia; Antranikian, Garabed

    2005-12-01

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

  2. DNA probe culture confirmation assay for identification of thermophilic Campylobacter species.

    PubMed Central

    Tenover, F C; Carlson, L; Barbagallo, S; Nachamkin, I

    1990-01-01

    We studied the ability of a new DNA probe-based assay system to correctly identify isolates of the thermophilic campylobacters Campylobacter jejuni, C. coli, and C. laridis grown in vitro. We examined 424 organisms, including 214 Campylobacter isolates and 210 other aerobic and anaerobic isolates. The probe assay, which uses a new homogeneous system in which all reactions take place within a single tube, demonstrated 100% accuracy, producing neither false-positive nor false-negative results. The assay does not, however, distinguish among C. jejuni, C. coli, and C. laridis. PMID:2380357

  3. Anaerobic fermentation of beef cattle manure. Final report

    SciTech Connect

    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.

  4. Effect of thermal alkaline pretreatment on the anaerobic digestion of wasted activated sludge.

    PubMed

    Vigueras-Carmona, S E; Ramírez, F; Noyola, A; Monroy, O

    2011-01-01

    The effect of alkaline pretreatment of waste-activated sludge, using two models to study the sequential hydrolysis rates of suspended (Sanders' surface model) and dissolved (Goel's saturation model) solids, on the mesophilic and thermophilic anaerobic digestion rate is evaluated. The pretreatment, which reduces the size of the solids, increases the reaction rate by increasing the surface area and the specific surface hydrolysis constant (K(SBK)); at thermophilic conditions from 0.45 x 10(-3) kg m(-2) d(-1) for the fresh sludge to 0.74 x 10(-3) kg m(-2) d(-1) for the pretreated sludge and at mesophilic conditions these values are 0.28 x 10(-3) kg m(-2) d(-1) and 0.47 x 10(-3) kg m(-2) d(-1) confirming the usefulness of a pretreatment for solids reduction. But for soluble solids, the thermoalkaline pretreatment decreases the reaction rates by inducing a competitive inhibition on the thermophilic anaerobic digestion rate while in the mesophilic range, a non-competitive inhibition is observed. A mathematical simulation of the consecutive reactions, suspended solids to dissolved solids and to methane in staged anaerobic thermophilic-mesophilic digestion, shows that with 4% suspended solids concentration it is better not to use a thermoalkaline pretreatment because overall solids reduction and total methane production are not as good as without pretreatment.

  5. Anaerobic Digestion.

    PubMed

    Liebetrau, Jan; Sträuber, Heike; Kretzschmar, Jörg; Denysenko, Velina; Nelles, Michael

    2017-04-09

    The term anaerobic digestion usually refers to the microbial conversion of organic material to biogas, which mainly consists of methane and carbon dioxide. The technical application of the naturally-occurring process is used to provide a renewable energy carrier and - as the substrate is often waste material - to reduce the organic matter content of the substrate prior to disposal.Applications can be found in sewage sludge treatment, the treatment of industrial and municipal solid wastes and wastewaters (including landfill gas utilization), and the conversion of agricultural residues and energy crops.For biorefinery concepts, the anaerobic digestion (AD) process is, on the one hand, an option to treat organic residues from other production processes. Concomitant effects are the reduction of organic carbon within the treated substance, the conversion of nitrogen and sulfur components, and the production of an energy-rich gas - the biogas. On the other hand, the multistep conversion of complex organic material offers the possibility of interrupting the conversion chain and locking out intermediates for utilization as basic material within the chemical industry.

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

    PubMed

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

    2014-06-01

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

  7. Thermophilic Fungi: Their Physiology and Enzymes†

    PubMed Central

    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. Thermophilic fungi: their physiology and enzymes.

    PubMed

    Maheshwari, R; Bharadwaj, G; Bhat, M K

    2000-09-01

    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 up 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 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

  9. Asymmetrical response of anaerobic digestion microbiota to temperature changes.

    PubMed

    Chapleur, Olivier; Mazeas, Laurent; Godon, Jean-Jacques; Bouchez, Théodore

    2015-10-22

    In natural settings, anaerobic digestion can take place in a wide temperature range, but industrial digesters are usually operated under either mesophilic (~35 °C) or thermophilic (~55 °C) conditions. The ability of anaerobic digestion microbiota to switch from one operating temperature to the other remains poorly documented. We therefore studied the effect of sudden temperature changes (35 °C/55 °C) in lab-scale bioreactors degrading (13)C-labelled cellulose. An asymmetric behaviour was observed. In terms of methane production, after an adaptation period, mesophilic inoculum exhibited a functional resistance to temperature increase but no functional resilience when temperature was reset to 35 °C, while thermophilic inoculum methanogenic activity strongly decreased under mesophilic conditions but partially recovered when temperature was reset to 55 °C. Automated ribosomal intergenic spacer analysis community fingerprints evidenced a strong influence of temperature on microbial diversity, particularly pronounced and persistent for Archaea. Key phylotypes involved in (13)C-cellulose degradation were identified with a coupled stable isotope probing (SIP)-16S rDNA pyrotag sequencing approach, suggesting that the hydrolytic and fermentative metabolic functions could be maintained thanks to functional redundancy between members of the class Clostridia, whereas methanogenic activity primarily relied on specialized groups affiliated either to genus Methanosarcina (mesophilic conditions), Methanothermobacter or Methanoculleus (thermophilic conditions) that were irreversibly modified by temperature increase.

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

    PubMed Central

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

    2016-01-01

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

  11. Microbiology and physiology of anaerobic fermentations of cellulose

    SciTech Connect

    Wiegel, J.

    1991-05-01

    The biochemistry and physiology of four major groups of anaerobic bacteria involved in the conversion of cellulose to methane or chemical feedstocks are examined. Aspects of metabolism which are relevant to the interactions and bioenergetics of consortia are being studied. Properties of the cellulolytic enzyme cluster of Clostridium thermocellum are investigated. Five different hydrogenases have been characterized in detail from anaerobic bacteria. Genes for different hydrogenases are being cloned and sequenced to determine their structural relationships. The role of metal clusters in activation of H{sub 2} is being investigated, as is the structure and role of metal clusters in formate metabolism. The function of formate in the total synthesis of acetate from CO{sub 2} and the role of this primary in anaerobes will be examined as well. Finally, these enzyme studies will be performed on thermophilic bacteria and new, pertinent species will be isolated. 50 refs., 3 figs., 1 tab.

  12. Thermophilic fungi isolated from a heated aquatic habitat

    SciTech Connect

    Ellis, D.H.

    1980-09-01

    The cooling pond for the Hazelwood Power Station, Morwell, Victoria, Australia, was studied for the presence of thermophilic fungi. A total of five species was recorded: Chaetomium thermophile, Aspergillus fumigatus, Humicola grisea, Humicola insolens, and Thermomyces lanuginosus. (ACR)

  13. Temporal variation of microbial population in a thermophilic biofilter for SO₂ removal.

    PubMed

    Zhang, Jingying; Li, Lin; Liu, Junxin

    2016-01-01

    The performance of a biofilter relies on the activity of microorganisms during the gas contaminant treatment process. In this study, SO2 was treated using a laboratory-scale biofilter packed with polyurethane foam cubes (PUFC), on which thermophilic desulfurization bacteria were attached. The thermophilic biofilter effectively reduced SO2 within 10months of operation time, with a maximum elimination capacity of 48.29 g/m(3)/hr. Temporal shifts in the microbial population in the thermophilic biofilter were determined through polymerase chain reaction-denaturing gradient gel electrophoresis and deoxyribonucleic acid (DNA) sequence analysis. The substrate species and environmental conditions in the biofilter influenced the microbial population. Oxygen distribution in the PUFC was analyzed using a microelectrode. When the water-containing rate in PUFC was over 98%, the oxygen distribution presented aerobic-anoxic-aerobic states along the test route on the PUFC. The appearance of sulfate-reducing bacteria was caused by the anaerobic conditions and sulfate formation after 4months of operation. Copyright © 2015. Published by Elsevier B.V.

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

    PubMed

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

    2016-05-01

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

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

    PubMed

    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.

  16. Fecal coliform population dynamics associated with the thermophilic stabilization of treated sewage sludge.

    PubMed

    Ziemba, Chris; Peccia, Jordan

    2012-10-26

    The inactivation of fecal coliforms in anaerobic batch reactors has been investigated at the thermophilic temperatures of 50, 55 and 60 °C. Throughout inactivation experiments at each temperature, individual colonies were isolated and identified by 16S rDNA gene sequencing to illustrate how the diversity of fecal coliforms is affected by thermophilic treatment. Results indicate that even though fecal coliforms in raw sewage sludge are comprised of several different bacterial species, each with variable temperature induced decay rates, the overall inactivation of fecal coliforms in raw sewage sludge was found to follow a first-order relationship. No tailing was observed across the range of fecal coliform concentrations measured. Fecal coliforms in raw sludge contained six different genera of bacteria and were 62% enriched in E. coli. Within 1.5 log removal of fecal coliform concentration by thermophilic treatment, the populations had shifted to, and remained at 100% E. coli. Subsequent inactivation rates measured in isolated fecal coliform strains confirmed that E. coli cells isolated post-treatment were more thermotolerant than E. coli and non-E coli bacteria isolated prior to thermal treatment. Overall, this study describes the potential enrichment of thermotolerant E. coli in biosolids fecal coliforms and demonstrates that while thermotolerant species are present at the end of treatment, pure first-order approximations are appropriate for estimating residence times to reduce fecal coliforms to levels promulgated in U.S. Class A biosolids standards.

  17. Potential Application of Anaerobic Extremophiles for Hydrogen Production

    NASA Technical Reports Server (NTRS)

    Pikuta, Elena V.; Hoover, Richard B.

    2004-01-01

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

  18. Potential Application of Anaerobic Extremophiles for Hydrogen Production

    NASA Technical Reports Server (NTRS)

    Pikuta, Elena V.; Hoover, Richard B.

    2004-01-01

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

  19. Effect of seeding during thermophilic composting of sewage sludge

    SciTech Connect

    Nakasaki, K.; Sasaki, M.; Shoda, M.; Kubota, H.

    1985-03-01

    The effect of seeding on the thermophilic composting of sewage sludge was examined by measuring the changes in CO/sub 2/ evolution rates and microbial numbers. Although the succession of thermophilic bacteria and thermophilic actinomycetes clearly reflected the effect of seeding, no clear difference was observed in the overall rate of composting or quality of the composted product. 7 references.

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

    PubMed

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

    2016-07-01

    In order to investigate the oxygen tolerance capacity of upflow anaerobic solid-state (UASS) with anaerobic filter (AF) system, the effect of microaeration on thermophilic anaerobic digestion of maize straw was investigated under batch conditions and in the UASS with AF system. Aeration intensities of 0-431mL O2/gvs were conducted as pretreatment under batch conditions. Aeration pretreatment obviously enhanced anaerobic digestion and an aeration intensity of 431mL O2/gvs increased the methane yield by 82.2%. Aeration intensities of 0-355mL O2/gvs were conducted in the process liquor circulation of the UASS with AF system. Dissolved oxygen (DO) of UASS and AF reactors kept around 1.39±0.27 and 0.99±0.38mg/L, respectively. pH was relatively stable around 7.11±0.04. Volatile fatty acids and soluble chemical oxygen demand concentration in UASS reactor were higher than those in AF reactor. Methane yield of the whole system was almost stable at 85±7mL/gvs as aeration intensity increased step by step. The UASS with AF system showed good oxygen tolerance capacity. Copyright © 2016. Published by Elsevier B.V.

  1. Fungal survival during anaerobic digestion of organic household waste.

    PubMed

    Schnürer, Anna; Schnürer, Johan

    2006-01-01

    Anaerobic digestion of organic waste yields energy rich biogas and retains nutrients (N, P, K, S, etc.) in a stabilised residue. For the residue to be used as a soil fertiliser, it must be free from pollutants and harmful microorganisms. Fungal survival during sanitation and anaerobic treatment of source-separated organic household waste and during aerobic storage of the residue obtained was investigated. Decimal reduction times were determined for inoculated fungi (Aspergillus flavus and Aspergillus fumigatus, Penicillium roqueforti, Rhizomucor pusillus, Thermoascus crustaceus and Thermomyces lanuginosus). Several different fungal species were found after waste sanitation treatment (70 degrees C, 1 h), with Aspergillus species dominating in non-inoculated waste. Anaerobic waste degradation decreased the diversity of fungal species for processes run at both 37 and 55 degrees C, but not total fungal colony forming units. Fungi surviving the mesophilic anaerobic digestion were mainly thermotolerant Talaromyces and Paecilomyces species. T. crustaceus and T. lanuginosus were the only inoculated fungi to survive the thermophilic anaerobic degradation process. Aerobic storage of both types of anaerobic residues for one month significantly decreased fungal counts.

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

    PubMed

    Zhu, Xinyu; Kougias, Panagiotis G; Treu, Laura; Campanaro, Stefano; Angelidaki, Irini

    2017-02-01

    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 of microbial community in granules was analysed using high-throughput sequencing of 16S ribosomal RNA gene amplicons, and the results showed that the temperature strictly determines the diversity of the microbial consortium. It was demonstrated that most of the microbes which were present in the initial mesophilic community were not found in the granules after the transition to thermophilic conditions. More specifically, only members from family Anaerolinaceae managed to tolerate the temperature change and contributed in maintaining the physical integrity of granular structure. On the contrary, new hydrolytic and fermentative bacteria were quickly replacing the old members in the community. A direct result from this abrupt change in the microbial diversity was the accumulation of volatile fatty acids and the concomitant pH drop in the reactor inhibiting the overall anaerobic digestion process. Nevertheless, by maintaining deliberately the pH levels at values higher than 6.5, a methanogen belonging to Methanoculleus genus emerged in the community enhancing the methane production.

  3. Bioprospecting thermophiles for cellulase production: a review

    PubMed Central

    Acharya, Somen; Chaudhary, Anita

    2012-01-01

    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. PMID:24031898

  4. Bioprospecting thermophiles for cellulase production: a review.

    PubMed

    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.

  5. Temperature-dependent transformation of biogas-producing microbial communities points to the increased importance of hydrogenotrophic methanogenesis under thermophilic operation.

    PubMed

    Pap, Bernadett; Györkei, Ádám; Boboescu, Iulian Zoltan; Nagy, Ildikó K; Bíró, Tibor; Kondorosi, Éva; Maróti, Gergely

    2015-02-01

    Stability of biogas production is highly dependent on the microbial community composition of the bioreactors. This composition is basically determined by the nature of biomass substrate and the physical-chemical parameters of the anaerobic digestion. Operational temperature is a major factor in the determination of the anaerobic degradation process. Next-generation sequencing (NGS)-based metagenomic approach was used to monitor the organization and operation of the microbial community throughout an experiment where mesophilic reactors (37°C) were gradually switched to thermophilic (55°C) operation. Temperature adaptation resulted in a clearly thermophilic community having a generally decreased complexity compared to the mesophilic system. A temporary destabilization of the system was observed, indicating a lag phase in the community development in response to temperature stress. Increased role of hydrogenotrophic methanogens under thermophilic conditions was shown, as well as considerably elevated levels of Fe-hydrogenases and hydrogen producer bacteria were observed in the thermophilic system. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. A molecular phylogeny of thermophilic fungi.

    PubMed

    Morgenstern, Ingo; Powlowski, Justin; Ishmael, Nadeeza; Darmond, Corinne; Marqueteau, Sandrine; Moisan, Marie-Claude; Quenneville, Geneviève; Tsang, Adrian

    2012-04-01

    Sequences from 86 fungal genomes and from the two outgroup genomes Arabidopsis thaliana and Drosophila melanogaster were analyzed to construct a robust molecular phylogeny of thermophilic fungi, which are potentially rich sources of industrial enzymes. To provide experimental reference points, growth characteristics of 22 reported thermophilic or thermotolerant fungi, together with eight mesophilic species, were examined at four temperatures: 22 °C, 34 °C, 45 °C, and 55 °C. Based on the relative growth performances, species with a faster growth rate at 45 °C than at 34 °C were classified as thermophilic, and species with better or equally good growth at 34 °C compared to 45 °C as thermotolerant. We examined the phylogenetic relationships of a diverse range of fungi, including thermophilic and thermotolerant species, using concatenated amino acid sequences of marker genes mcm7, rpb1, and rpb2 obtained from genome sequencing projects. To further elucidate the phylogenetic relationships in the thermophile-rich orders Sordariales and Eurotiales, we used nucleotide sequences from the nuclear ribosomal small subunit (SSU), the 5.8S gene with internal transcribed spacers 1 and 2 (ITS 1 and 2), and the ribosomal large subunit (LSU) to include additional species for analysis. These phylogenetic analyses clarified the position of several thermophilic taxa. Thus, Myriococcum thermophilum and Scytalidium thermophilum fall into the Sordariales as members of the Chaetomiaceae, Thermomyces lanuginosus belongs to the Eurotiales, Malbranchea cinnamomea is a member of the Onygenales, and Calcarisporiella thermophila is assigned to the basal fungi close to the Mucorales. The mesophilic alkalophile Acremonium alcalophilum clusters with Verticillium albo-atrum and Verticillium dahliae, placing them in the recently established order Glomerellales. Taken together, these data indicate that the known thermophilic fungi are limited to the Sordariales, Eurotiales, and

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

    PubMed

    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.

  8. Identification and Phylogenetic analysis of thermophilic sulfate-reducing bacteria in oil field samples by 16S rDNA gene cloning and sequencing.

    PubMed

    Leu, J Y; McGovern-Traa, C P; Porter, A J; Harris, W J; Hamilton, W A

    1998-06-01

    Thermophilic sulfate-reducing bacteria (SRB) have been recognized as an important source of hydrogen sulfide (H2S) in hydrocarbon reservoirs and in production systems. Four thermophilic SRB enrichment cultures from three different oil field samples (sandstone core, drilling mud, and production water) were investigated using 16S rDNA sequence comparative analysis. In total, 15 different clones were identified. We found spore-forming, low G+C content, thermophilic, sulfate-reducing Desulfotomaculum-related sequences present in all oil field samples, and additionally a clone originating from sandstone core which was assigned to the mesophilic Desulfomicrobium group. Furthermore, three clones related to Gram-positive, non-sulfate-reducing Thermoanaerobacter species and four clones close to Clostridium thermocopriae were found in enrichment cultures from sandstone core and from production water, respectively. In addition, the deeply rooted lineage of two of the clones suggested previously undescribed, Gram-positive, low G+C content, thermophilic, obligately anaerobic bacteria present in production water. Such thermophilic, non-sulfate-reducing microorganisms may play an important ecological role alongside SRB in oil field environments.

  9. Degradation of xylan by a new strain of thermophilic Clostridium

    SciTech Connect

    Boyce, E.N.

    1988-01-01

    The intent of the research has been the isolation of a thermophilic, polysaccharide-degrading anaerobe which could prove suitable for coculturing with organisms such as Clostridium thermocellum, a prominent cellulose-degrading bacterium. The author has isolated such an organism from Kansas soil. The isolate virgorously degrades xylan, a hemicellulose, as well as several starchy substrates and other polysaccharides, though not cellulose. In addition, the isolate ferments all common mono- and di-saccharide components of plant polysaccharides. Though its fermentation is largely acidic, it also produces significant amounts of enthanol and n-butanol. Biochemical and metabolic characterization of the isolate have allowed it to be distinguished from previously-reported strains of the genus Clostridium, though currently insufficient evidence is available to report it as a new species. Initial studies of the isolate's xylan-degrading system reveal that the organism produces at least six separate xylanases when the isolate grows in media containing xylose, a component of xylan. In xylan medium, the isolate also produces a yellow, high-charged substance which co-migrates electrophoretically with its active xylanase(s). This substance may be analogous to the yellow substrate affinity substance (YAS) produced by C. thermocellum in cellulose medium.

  10. Characterization of the xylanases from the new isolated thermophilic xylan-degrading Bacillus thermoleovorans strain K-3d and Bacillus flavothermus strain LB3A.

    PubMed

    Sunna, A; Prowe, S G; Stoffregen, T; Antranikian, G

    1997-03-15

    Three strictly aerobic strains (K-1, K-3d and K-4) were isolated from a hot-spring in Kobe, Japan, and a facultative anaerobic strain LB3A was isolated from sediments collected from the alkaline Lake Bogoria, Kenya. All strains were thermophilic and capable of growth on xylan. On the basis of morphological, physiological and phylogenetic studies the new aerobic isolates resemble the thermophilic species Bacillus thermoleovorans while the facultative anaerobic isolate LB3A resembles the facultative anaerobic thermophilic species Bacillus flavothermus. When grown on xylan as sole carbon source, all isolates produce thermoactive xylanases, Xylanases from strains K-3d and LB3A are active at temperatures between 40 and 90 degrees C and pH values between 5.0 and 9.0. Applying SDS-PAGE the crude xylanase complex of isolate K-3d was shown to be composed of two active bands, with molecular masses of 40 and 69 kDa. The crude xylanase complex of isolate LB3A, on the other hand, is composed of at least four activity bands with molecular masses ranging from 80 to 130 kDa. Due to the product pattern of xylan hydrolysis both enzymes are classified as endoxylanases. The xylanolytic enzyme system of isolate K-3d produces xylotriose, xylotetraose and larger xylooligosacharides, whereas the xylanases from isolate LB3A release xylotetraose as the major product of hydrolysis.

  11. Systematic Underutilization of Glutamine In Thermophile Proteins

    NASA Technical Reports Server (NTRS)

    Liang, Shoudan; Weber, Arthur; Biegel, Bryan A. (Technical Monitor)

    2002-01-01

    Rapid racemization above 100 C of L-amino acids to Domino acids, as well as deamidation, is probably a hazard for high temperature life. For example, the half-life of some asparaginyl peptides can be as short as 10 minutes at 100 C. High temperature organisms could protect themselves by reducing usage of amino acids that are easily racemized/deamidazed, by having a rapid rate of protein turnover which requires energy, or by adapting special cis-peptide conformations. We have searched eight completely sequenced thermophile genomes, and compare them to mesophile genomes, in order to identify underutilized amino acids. To our surprise, asparagine, the most unstable amino acid to deamidation, is used at about the same level in thermophile proteins in comparison to mesophiles whereas it is the second most unstable amino acid, glutamine, that is underutilized in all of eight thermophile species. Glutamines are present at 2% level in a typical thermophile protein, instead of 4% in mesophile. We argue that it is easier to protect asparagines from deamidation by cis-peptide conformations. We discuss statistical as well as structural evidence in support of our conclusions.

  12. Systematic Underutilization of Glutamine In Thermophile Proteins

    NASA Technical Reports Server (NTRS)

    Liang, Shoudan; Weber, Arthur; Biegel, Bryan A. (Technical Monitor)

    2002-01-01

    Rapid racemization above 100 C of L-amino acids to Domino acids, as well as deamidation, is probably a hazard for high temperature life. For example, the half-life of some asparaginyl peptides can be as short as 10 minutes at 100 C. High temperature organisms could protect themselves by reducing usage of amino acids that are easily racemized/deamidazed, by having a rapid rate of protein turnover which requires energy, or by adapting special cis-peptide conformations. We have searched eight completely sequenced thermophile genomes, and compare them to mesophile genomes, in order to identify underutilized amino acids. To our surprise, asparagine, the most unstable amino acid to deamidation, is used at about the same level in thermophile proteins in comparison to mesophiles whereas it is the second most unstable amino acid, glutamine, that is underutilized in all of eight thermophile species. Glutamines are present at 2% level in a typical thermophile protein, instead of 4% in mesophile. We argue that it is easier to protect asparagines from deamidation by cis-peptide conformations. We discuss statistical as well as structural evidence in support of our conclusions.

  13. Anaerobic Codigestion of Grass and Sewage Sludge: Laboratory Experiments and Feasibility Analysis.

    PubMed

    Hidaka, Taira; Wang, Feng; Sakurai, Kensuke; Tsumori, Jun; Minamiyama, Mizuhiko

    2016-11-01

      Grass is drawing attention for its high potential for biogas production. Anaerobic digesters in wastewater treatment plants can be used for producing biogas by processing grass without having to invest in the construction of new treatment facilities. Batch and continuous digestion experiments were conducted to assess the feasibility of codigestion of sewage sludge and grass. The focus was on a thermophilic condition, starting-up from existing mesophilic anaerobic digestion of sewage sludge only. The batch and continuous experiments used two different sewage sludges. Results demonstrated a methane generation of approximately 0.2 normal liter-methane/g volatile solids-grass. The addition of grass did not affect the ammonia concentration and improved the dewaterability of the digested sludge. The start-up performance from mesophilic digested sewage sludge to thermophilic codigestion with grass was confirmed. A feasibility analysis demonstrated that codigestion is applicable in terms of energy recovery and greenhouse gas emission, depending on the transport distance of grass.

  14. Methanogenic population dynamics during start-up of anaerobic digesters treating municipal solid waste and biosolids

    SciTech Connect

    Griffin, M.E.; McMahon, K.D.; Mackie, R.I.; Raskin, L.

    1998-02-05

    An aggressive start-up strategy was used to initiate codigestion in two anaerobic, continuously mixed bench-top reactors at mesophilic (37 C) and thermophilic (55 C) conditions. The digesters were inoculated with mesophilic anaerobic sewage sludge and cattle manure and were fed a mixture of simulated municipal solid waste and biosolids in proportions that reflect US production rates. The design organic loading rate was 3.1 kg volatile solids/m{sup 3}/day and the retention time was 20 days. Ribosomal RNA-targeted oligonucleotide probes were used to determine the methanogenic community structure in the inocula and the digesters. Chemical analyses were performed to evaluate digester performance. The aggressive start-up strategy was successful for the thermophilic reactor, despite the use of a mesophilic inoculum.

  15. Livestock Anaerobic Digester Database

    EPA Pesticide Factsheets

    The Anaerobic Digester Database provides basic information about anaerobic digesters on livestock farms in the United States, organized in Excel spreadsheets. It includes projects that are under construction, operating, or shut down.

  16. Roles of Thermophiles and Fungi in Bitumen Degradation in Mostly Cold Oil Sands Outcrops.

    PubMed

    Wong, Man-Ling; An, Dongshan; Caffrey, Sean M; Soh, Jung; Dong, Xiaoli; Sensen, Christoph W; Oldenburg, Thomas B P; Larter, Steve R; Voordouw, Gerrit

    2015-10-01

    Oil sands are surface exposed in river valley outcrops in northeastern Alberta, where flat slabs (tablets) of weathered, bitumen-saturated sandstone can be retrieved from outcrop cliffs or from riverbeds. Although the average yearly surface temperature of this region is low (0.7°C), we found that the temperatures of the exposed surfaces of outcrop cliffs reached 55 to 60°C on sunny summer days, with daily maxima being 27 to 31°C. Analysis of the cooccurrence of taxa derived from pyrosequencing of 16S/18S rRNA genes indicated that an aerobic microbial network of fungi and hydrocarbon-, methane-, or acetate-oxidizing heterotrophic bacteria was present in all cliff tablets. Metagenomic analyses indicated an elevated presence of fungal cytochrome P450 monooxygenases in these samples. This network was distinct from the heterotrophic community found in riverbeds, which included fewer fungi. A subset of cliff tablets had a network of anaerobic and/or thermophilic taxa, including methanogens, Firmicutes, and Thermotogae, in the center. Long-term aerobic incubation of outcrop samples at 55°C gave a thermophilic microbial community. Analysis of residual bitumen with a Fourier transform ion cyclotron resonance mass spectrometer indicated that aerobic degradation proceeded at 55°C but not at 4°C. Little anaerobic degradation was observed. These results indicate that bitumen degradation on outcrop surfaces is a largely aerobic process with a minor anaerobic contribution and is catalyzed by a consortium of bacteria and fungi. Bitumen degradation is stimulated by periodic high temperatures on outcrop cliffs, which cause significant decreases in bitumen viscosity. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  17. Roles of Thermophiles and Fungi in Bitumen Degradation in Mostly Cold Oil Sands Outcrops

    PubMed Central

    Wong, Man-Ling; An, Dongshan; Caffrey, Sean M.; Soh, Jung; Dong, Xiaoli; Sensen, Christoph W.; Oldenburg, Thomas B. P.; Larter, Steve R.

    2015-01-01

    Oil sands are surface exposed in river valley outcrops in northeastern Alberta, where flat slabs (tablets) of weathered, bitumen-saturated sandstone can be retrieved from outcrop cliffs or from riverbeds. Although the average yearly surface temperature of this region is low (0.7°C), we found that the temperatures of the exposed surfaces of outcrop cliffs reached 55 to 60°C on sunny summer days, with daily maxima being 27 to 31°C. Analysis of the cooccurrence of taxa derived from pyrosequencing of 16S/18S rRNA genes indicated that an aerobic microbial network of fungi and hydrocarbon-, methane-, or acetate-oxidizing heterotrophic bacteria was present in all cliff tablets. Metagenomic analyses indicated an elevated presence of fungal cytochrome P450 monooxygenases in these samples. This network was distinct from the heterotrophic community found in riverbeds, which included fewer fungi. A subset of cliff tablets had a network of anaerobic and/or thermophilic taxa, including methanogens, Firmicutes, and Thermotogae, in the center. Long-term aerobic incubation of outcrop samples at 55°C gave a thermophilic microbial community. Analysis of residual bitumen with a Fourier transform ion cyclotron resonance mass spectrometer indicated that aerobic degradation proceeded at 55°C but not at 4°C. Little anaerobic degradation was observed. These results indicate that bitumen degradation on outcrop surfaces is a largely aerobic process with a minor anaerobic contribution and is catalyzed by a consortium of bacteria and fungi. Bitumen degradation is stimulated by periodic high temperatures on outcrop cliffs, which cause significant decreases in bitumen viscosity. PMID:26209669

  18. Sludge properties and their effects on membrane fouling in submerged anaerobic membrane bioreactors (SAnMBRs).

    PubMed

    Lin, H J; Xie, K; Mahendran, B; Bagley, D M; Leung, K T; Liss, S N; Liao, B Q

    2009-08-01

    Two submerged anaerobic membrane bioreactors (SAnMBRs) (thermophilic vs. mesophilic) were operated for a period of 3.5 months with kraft evaporator condensate at a feed chemical oxygen demand of 10,000 mg/L. The results show that the filtration behavior of the two systems was significantly different. The filtration resistance in the thermophilic SAnMBR was about 5-10 times higher than that of the mesophilic system when operated under similar hydrodynamic conditions. Comparison of sludge properties and cake layer structure from the two systems was made to elucidate major factors governing the different filtration characteristics. There were more soluble microbial products (SMP) and biopolymer clusters (BPC) produced and a larger portion of fine flocs (<15 microm) in the thermophilic SAnMBR. Analysis of bound extracellular polymeric substances (EPS) showed that the thermophilic sludge had a higher protein/polysaccharide ratio in EPS, as compared to that in the mesophilic sludge. A series of analyses, including Fourier transform infrared (FTIR) spectroscopy, energy dispersive X-ray spectroscopy (EDX), confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), atomic force microscopy (AFM) and particle size analyzer showed that the cake layer formed in the thermophilic SAnMBR contained higher levels of both organic and inorganic foulants, smaller particle sizes, and especially, a denser and more compact sludge cake structure. These results indicate that floc size, SMP, BPC, bound EPS as well as cake layer structure are the major factors governing membrane fouling in SAnMBR systems.

  19. Lutispora thermophila gen. nov., sp. nov., a thermophilic, spore-forming bacterium isolated from a thermophilic methanogenic bioreactor digesting municipal solid wastes.

    PubMed

    Shiratori, Hatsumi; Ohiwa, Hitomi; Ikeno, Hironori; Ayame, Shohei; Kataoka, Naoaki; Miya, Akiko; Beppu, Teruhiko; Ueda, Kenji

    2008-04-01

    A novel anaerobic, moderately thermophilic, spore-forming, rod-shaped bacterium (strain EBR46T) was isolated from an enrichment culture derived from an anaerobic thermophilic (55 degrees C) methanogenic bioreactor treating artificial solid wastes. Phylogeny based on 16S rRNA gene sequence analysis placed strain EBR46T within a distinct lineage between Clostridium clusters II and III. The closest recognized relative of strain EBR46T was Gracilibacter thermotolerans DSM 17427T (85.3 % 16S rRNA gene sequence similarity). The DNA G+C content of strain EBR46T was 36.2 mol%. The novel strain grew optimally at 55-58 degrees C and at pH 7.5-8.0 and was able to grow on peptone, tryptone, Casamino acids, casein hydrolysate, methionine, threonine, tryptophan, cysteine, lysine and serine in the presence of 0.2 % yeast extract. Carbohydrates were not utilized. The main products from tryptone utilization were acetate, iso-butyrate, propionate and iso-valerate. Strain EBR46T produced hydrogen sulfide from cysteine. The major fatty acids were iso-C15 : 0, C14 : 0, C16 : 0 DMA (dimethyl acetal) and iso-C15 : 0 DMA. Based on its unique phylogenetic and physiological features, strain EBR46T is considered to represent a novel species of a new genus, for which the name Lutispora thermophila gen. nov., sp. nov. is proposed. The type strain of the type species is EBR46T (=NBRC 102133T=DSM 19022T).

  20. Development of anaerobic digestion methods for palm oil mill effluent (POME) treatment.

    PubMed

    Poh, P E; Chong, M F

    2009-01-01

    Palm oil mill effluent (POME) is a highly polluting wastewater that pollutes the environment if discharged directly due to its high chemical oxygen demand (COD) and biochemical oxygen demand (BOD) concentration. Anaerobic digestion has been widely used for POME treatment with large emphasis placed on capturing the methane gas released as a product of this biodegradation treatment method. The anaerobic digestion method is recognized as a clean development mechanism (CDM) under the Kyoto protocol. Certified emission reduction (CER) can be obtained by using methane gas as a renewable energy. This review aims to discuss the various anaerobic treatments of POME and factors that influence the operation of anaerobic treatment. The POME treatment at both mesophilic and thermophilic temperature ranges are also analyzed.

  1. Evaluation of Integrated Anaerobic Digestion and Hydrothermal Carbonization for Bioenergy Production

    PubMed Central

    Reza, M. Toufiq; Werner, Maja; Pohl, Marcel; Mumme, Jan

    2014-01-01

    Lignocellulosic biomass is one of the most abundant yet underutilized renewable energy resources. Both anaerobic digestion (AD) and hydrothermal carbonization (HTC) are promising technologies for bioenergy production from biomass in terms of biogas and HTC biochar, respectively. In this study, the combination of AD and HTC is proposed to increase overall bioenergy production. Wheat straw was anaerobically digested in a novel upflow anaerobic solid state reactor (UASS) in both mesophilic (37 °C) and thermophilic (55 °C) conditions. Wet digested from thermophilic AD was hydrothermally carbonized at 230 °C for 6 hr for HTC biochar production. At thermophilic temperature, the UASS system yields an average of 165 LCH4/kgVS (VS: volatile solids) and 121 L CH4/kgVS at mesophilic AD over the continuous operation of 200 days. Meanwhile, 43.4 g of HTC biochar with 29.6 MJ/kgdry_biochar was obtained from HTC of 1 kg digestate (dry basis) from mesophilic AD. The combination of AD and HTC, in this particular set of experiment yield 13.2 MJ of energy per 1 kg of dry wheat straw, which is at least 20% higher than HTC alone and 60.2% higher than AD only. PMID:24962786

  2. Evaluation of integrated anaerobic digestion and hydrothermal carbonization for bioenergy production.

    PubMed

    Reza, M Toufiq; Werner, Maja; Pohl, Marcel; Mumme, Jan

    2014-06-15

    Lignocellulosic biomass is one of the most abundant yet underutilized renewable energy resources. Both anaerobic digestion (AD) and hydrothermal carbonization (HTC) are promising technologies for bioenergy production from biomass in terms of biogas and HTC biochar, respectively. In this study, the combination of AD and HTC is proposed to increase overall bioenergy production. Wheat straw was anaerobically digested in a novel upflow anaerobic solid state reactor (UASS) in both mesophilic (37 °C) and thermophilic (55 °C) conditions. Wet digested from thermophilic AD was hydrothermally carbonized at 230 °C for 6 hr for HTC biochar production. At thermophilic temperature, the UASS system yields an average of 165 LCH4/kgVS (VS: volatile solids) and 121 L CH4/kgVS at mesophilic AD over the continuous operation of 200 days. Meanwhile, 43.4 g of HTC biochar with 29.6 MJ/kgdry_biochar was obtained from HTC of 1 kg digestate (dry basis) from mesophilic AD. The combination of AD and HTC, in this particular set of experiment yield 13.2 MJ of energy per 1 kg of dry wheat straw, which is at least 20% higher than HTC alone and 60.2% higher than AD only.

  3. Anaerobic digestion of tannery waste: semi-continuous and anaerobic sequencing batch reactor processes.

    PubMed

    Zupancic, Gregor D; Jemec, A

    2010-01-01

    Disposal of the vast amounts of tannery waste that are currently generated is a significant problem. Anaerobic treatment of different types of tannery waste (fleshings, skin trimmings and wastewater sludge) was investigated. The biochemical methane potential is the same at 37 degrees C or 55 degrees C and an assay of this was shown to be an appropriate screening tool with which to estimate the susceptibility of a substrate to anaerobic digestion. The start-up procedure of a tannery waste thermophilic anaerobic digestion in 100 days using seed from mesophilic digester processing municipal sludge is presented. The specific methane production potential at 55 degrees C is estimated to be 0.617 m(3)kg(-1) of volatile suspended solids for tannery waste sludge, 0.377 m(3)kg(-1) for tannery waste trimmings and 0.649 m(3)kg(-1) for tannery waste fleshings. Additional concerns such as chromium content, salinity and temperature fluctuations were also addressed. Chromium content and salinity showed no adverse effects; however a reactor temperature reduction of 4.4 degrees C led to a drop in biogas production of 25%, indicating a requirement to keep the temperature constant at 55 degrees C.

  4. Quinolone activity against anaerobes.

    PubMed

    Appelbaum, P C

    1999-01-01

    The first generation of fluoroquinolones such as ciprofloxacin and ofloxacin are inactive against most anaerobic bacteria. However, some broad-spectrum quinolones, which have recently become clinically available or are under active development, have significant antianaerobic activity. This review summarises the in vitro activity of currently available, as well as experimental, quinolones against clinically significant anaerobic bacteria. Quinolones with low activity against anaerobes include ciprofloxacin, ofloxacin, levofloxacin, fleroxacin, pefloxacin, enoxacin and lomefloxacin. Compounds with intermediate antianaerobic activity include sparfloxacin and grepafloxacin. Trovafloxacin, gatifloxacin and moxifloxacin yield low MICs against most groups of anaerobes. Quinolones with the greatest in vitro activity against anaerobes include clinafloxacin and sitafloxacin (DU-6859a).

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

    SciTech Connect

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

    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.

  6. Complete genome sequence of the thermophilic sulfate-reducing ocean bacterium Thermodesulfatator indicus type strain (CIR29812T)

    PubMed Central

    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

    2012-01-01

    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. PMID:22768359

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

    PubMed

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

    2011-05-01

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

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

    PubMed

    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

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

    PubMed Central

    Li, Duo-Chuan; Li, An-Na; Papageorgiou, Anastassios C.

    2011-01-01

    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. PMID:22145076

  10. Cellulases from thermophilic fungi: recent insights and biotechnological potential.

    PubMed

    Li, Duo-Chuan; Li, An-Na; Papageorgiou, Anastassios C

    2011-01-01

    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.

  11. Middle-thermophilic sulfur-oxidizing bacteria Thiomonas sp. RAN5 strain for hydrogen sulfide removal.

    PubMed

    Asano, Ryoki; Hirooka, Kayako; Nakai, Yutaka

    2012-01-01

    Hydrogen sulfide (H2S) is one of the most toxic and offensively odorous gases and is generated in anaerobic bioreactors. A middle-thermophilic sulfur-oxidizing bacterium (SOB), Thiomonas sp. strain RAN5, was isolated and applied for H2S removal from both artificial and anaerobically digested gas. When a bioreactor containing medium inoculated with RAN5 was aerated continuously with artificial gas (containing 100 ppm H2S) at 45 degrees C for 156 hr, the H2S concentration in the vented gas was reduced by 99%. This was not affected by the presence of other microbes in the bioreactor The H2S removal efficiency of the RAN5 bioreactor for anaerobically digested gas was greater than 99% at influent H2S concentrations ranging from 2 to 1800 ppm; the efficiency decreased to 90% at influent H2S concentrations greater than 2000 ppm. Thiomonas sp. strain RAN5 cannot survive at room temperature, and thus its leakage from a wastewater treatment plant would not damage sewage systems. These data suggest that Thiomonas sp. strain RAN5 may be a useful microorganism for H2S removal.

  12. Microbial population dynamics during long-term sludge adaptation of thermophilic and mesophilic sequencing batch digesters treating sewage fine sieved fraction at varying organic loading rates.

    PubMed

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

    2015-01-01

    In this research, the feasibility of, and population dynamics in, one-step anaerobic sequencing batch reactor systems treating the fine sieved fraction (FSF) from raw municipal wastewater was studied under thermophilic (55 °C) and mesophilic (35 °C) conditions. FSF was sequestered from raw municipal wastewater, in the Netherlands, using a rotating belt filter (mesh size 350 micron). FSF is a heterogeneous substrate that mainly consists of fibres originating from toilet paper and thus contains a high cellulosic fraction (60-80 % of total solids content), regarded as an energy-rich material. Results of the 656-day fed-batch operation clearly showed that thermophilic digestion was more stable, applying high organic loading rates (OLR) up to 22 kg COD/(m(3) day). In contrast, the mesophilic digester already failed applying an OLR of 5.5 kg COD/(m(3) day), indicated by a drop in pH and increase in volatile fatty acids (VFAs). The observed viscosity values of the mesophilic sludge were more than tenfold higher than the thermophilic sludge. 454-pyrosequencing of eight mesophilic and eight thermophilic biomass samples revealed that Bacteroides and aceticlastic methanogen Methanosaeta were the dominant genera in the mesophilic digester, whereas OP9 lineages, Clostridium and the hydrogenotrophic methanogen Methanothermobacter dominated the thermophilic one. Our study suggests that applying thermophilic conditions for FSF digestion would result in a higher biogas production rate and/or a smaller required reactor volume, comparing to mesophilic conditions.

  13. Thermophilic biohydrogen production: how far are we?

    PubMed

    Pawar, Sudhanshu S; van Niel, Ed W J

    2013-09-01

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

  14. Thermophilic enzymes and their biotechnological potential.

    PubMed

    Lasa, I; Berenguer, J

    1993-12-01

    The ability of many microorganisms to grow at high temperatures has held a particular fascination for microbiologists and biochemists since a long time. As any of their cellular components, their proteins are inherently more stable to heat than those of conventional organisms. This thermal stability is not due to any specific characteristic, but results a consequence of various changes which contribute to the whole stability of the protein in an additive manner. These enzymes are not only more thermostable, but also more resistant to chemical agents than their mesophilic homologous, what makes them extremely interesting for industrial processes. Despite this, most of the enzymes used at present in industrial processes have been isolated from mesophiles due to the limited knowledge and difficulties to grow thermophiles in high scale. The objective of this review is to consider briefly the importance of the thermostability in order to apply enzymes in the industry, and to overview the most recent advances in the identification of new thermophilic organisms and enzymes. Furthermore, the recent development of genetic model systems for moderate and extreme thermophiles are referred.

  15. Advanced thermophilic digestion of biomass blends

    SciTech Connect

    Ghosh, S.

    1982-05-01

    The development of an advanced thermophilic biomass-digestion process that could be operated at much higher loading and slurry throughput rates than those of conventional high-rate digestion was reported. The biomass blend (mixture of hyacinth, Bermuda grass, refuse, and sludge) effected superior digester performance than the pure biomass feeds. For the pure feeds, mesophilic (35/sup 0/C) digestion was better than thermophilic (55/sup 0/C) digestion; the reverse was true for the biomass-waste blend substrate. The blend feed had higher biodegradability, and was selected as the substrate for an advanced digestion process. The advanced thermophilic process consisted of alkaline pretreatment of the undiluted blend feed at 55/sup 0/C, recycling of spent alkali to treat the fresh feed, neutralization of the treated feed with digester gas to a high pH (9 to 10), and digestion in a complete-mix digester. Methane yield and gas production rate from the advanced process were significantly higher than those from conventional digestion despite the fact that loading and hydraulic throughput rates for the former process were considerably higher than those of the latter. Reactor volume for the advanced process could be less than 20% and net energy production more than double those for conventional mesophilic high-rate digestion.

  16. Thermophilic fungi in an aridland ecosystem.

    PubMed

    Powell, Amy J; Parchert, Kylea J; Bustamante, Joslyn M; Ricken, J Bryce; Hutchinson, Miriam I; Natvig, Donald O

    2012-01-01

    We report a comprehensive multi-year study of thermophilic fungi at the Sevilleta National Wildlife Refuge in central New Mexico. Recovery of thermophilic fungi from soils showed seasonal fluctuations, with greater abundance correlating with spring and summer precipitation peaks. In addition to grassland soils, we obtained and characterized isolates from grassland and riparian litter, herbivore dung and biological soil crusts. All strains belonged to either the Eurotiales or Sordariales (Chaetomiaceae). No particular substrate or microhabitat associations were detected. Molecular typing of strains revealed substantial phylogenetic diversity, eight ad hoc phylogroups across the two orders were identified and genetic diversity was present within each phylogroup. Growth tests over a range of temperatures showed substantial variation in maximum growth rates among strains and across phylogroups but consistency within phylogroups. Results demonstrated that 45-50 C represents the optimal temperature for growth of most isolates, with a dramatic decline at 60 C. Most strains grew at 60 C, albeit slowly, whereas none grew at 65 C, providing empirical confirmation that 60 C presents an evolutionary threshold for fungal growth. Our results support the hypothesis that fungal thermophily is an adaptation to transient seasonal and diurnal high temperatures, rather than simply an adaptation to specialized high-temperature environments. We note that the diversity observed among strains and the frequently confused taxonomy within these groups highlight the need for comprehensive biosystematic revision of thermophilic taxa in both orders.

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

    PubMed

    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. Phylogenetic Analysis of Bacterial Communities in Mesophilic and Thermophilic Bioreactors Treating Pharmaceutical Wastewater

    PubMed Central

    LaPara, Timothy M.; Nakatsu, Cindy H.; Pantea, Lisa; Alleman, James E.

    2000-01-01

    The phylogenetic diversity of the bacterial communities supported by a seven-stage, full-scale biological wastewater treatment plant was studied. These reactors were operated at both mesophilic (28 to 32°C) and thermophilic (50 to 58°C) temperatures. Community fingerprint analysis by denaturing gradient gel electrophoresis (DGGE) of the PCR-amplified V3 region of the 16S rRNA gene from the domain Bacteria revealed that these seven reactors supported three distinct microbial communities. A band-counting analysis of the PCR-DGGE results suggested that elevated reactor temperatures corresponded with reduced species richness. Cloning of nearly complete 16S rRNA genes also suggested a reduced species richness in the thermophilic reactors by comparing the number of clones with different nucleotide inserts versus the total number of clones screened. While these results imply that elevated temperature can reduce species richness, other factors also could have impacted the number of populations that were detected. Nearly complete 16S rDNA sequence analysis showed that the thermophilic reactors were dominated by members from the β subdivision of the division Proteobacteria (β-proteobacteria) in addition to anaerobic phylotypes from the low-G+C gram-positive and Synergistes divisions. The mesophilic reactors, however, included at least six bacterial divisions, including Cytophaga-Flavobacterium-Bacteroides, Synergistes, Planctomycetes, low-G+C gram-positives, Holophaga-Acidobacterium, and Proteobacteria (α-proteobacteria, β-proteobacteria, γ-proteobacteria and δ-proteobacteria subdivisions). The two PCR-based techniques detected the presence of similar bacterial populations but failed to coincide on the relative distribution of these phylotypes. This suggested that at least one of these methods is insufficiently quantitative to determine total community biodiversity—a function of both the total number of species present (richness) and their relative distribution

  19. LC-ESI-MS/MS identification of polar lipids of two thermophilic Anoxybacillus bacteria containing a unique lipid pattern.

    PubMed

    Rezanka, Tomáš; Kambourova, Margarita; Derekova, Anna; Kolouchová, Irena; Sigler, Karel

    2012-07-01

    Phospholipids and glycolipids from two recently described species belonging to the thermophilic genus Anoxybacillus were analyzed by liquid chromatography-electrospray tandem mass spectrometry (LC/ESI-MS/MS). Analysis of total lipids from the facultatively anaerobic A. bogrovensis on a HILIC (Hydrophilic Interaction LIquid Chromatography) column succeeded in separating diacyl- and plasmalogen phospholipids. The LC/ESI-MS/MS analysis of the strict aerobe A. rupiensis revealed the presence of different unique polar lipids, predominantly alanyl-, lysyl-, and glucosyl-phosphatidylglycerols and cardiolipins. Each of the classes of polar lipids was then analyzed by means of the ESI-MS/MS and more than 140 molecular species of six lipid classes from A. bogrovensis and nearly 200 molecular species of nine classes of polar lipids from A. rupiensis were identified. Five classes of unidentified polar lipids were detected in both strains. Plasmalogens were thus determined for the first time in a facultatively anaerobic bacterium, i.e. A. bogrovensis.

  20. UASB performance and microbial adaptation during a transition from mesophilic to thermophilic treatment of palm oil mill effluent.

    PubMed

    Khemkhao, Maneerat; Nuntakumjorn, Boonyarit; Techkarnjanaruk, Somkiet; Phalakornkule, Chantaraporn

    2012-07-30

    The treatment of palm oil mill effluent (POME) by an upflow anaerobic sludge bed (UASB) at organic loading rates (OLR) between 2.2 and 9.5 g COD l(-1) day(-1) was achieved by acclimatizing the mesophilic (37 °C) microbial seed to the thermophilic temperature (57 °C) by a series of stepwise temperature shifts. The UASB produced up to 13.2 l biogas d(-1) with methane content on an average of 76%. The COD removal efficiency ranged between 76 and 86%. Microbial diversity of granules from the UASB reactor was also investigated. The PCR-based DGGE analysis showed that the bacterial population profiles significantly changed with the temperature transition from mesophilic to thermophilic conditions. In addition, the results suggested that even though the thermophilic temperature of 57 °C was suitable for a number of hydrolytic, acidogenic and acetogenic bacteria, it may not be suitable for some Methanosaeta species acclimatized from 37 °C. Specifically, the bands associated with Methanosaeta thermophila PT and Methanosaeta harundinacea can be detected during the four consecutive operation phases of 37 °C, 42 °C, 47 °C and 52 °C, but their corresponding bands were found to fade out at 57 °C. The DGGE analysis predicted that the temperature transition can result in significant methanogenic biomass washout at 57 °C. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Comparison of the methane production potential and biodegradability of kitchen waste from different sources under mesophilic and thermophilic conditions.

    PubMed

    Yang, Ziyi; Wang, Wen; Zhang, Shuyu; Ma, Zonghu; Anwar, Naveed; Liu, Guangqing; Zhang, Ruihong

    2017-04-01

    The methane production potential of kitchen waste (KW) obtained from different sources was compared through mesophilic and thermophilic anaerobic digestion. The methane yields (MYs) obtained with the same KW sample under different temperatures were similar, whereas the MYs obtained with different samples differed significantly. The highest MY obtained in S7 was 54%-60% higher than the lowest MY in S3. The modified Gompertz model was utilized to simulate the methane production process. The maximum production rate of methane under thermophilic conditions was 2%-86% higher than that under mesophilic conditions. The characteristics of different KW samples were studied. In the distribution of total chemical oxygen demand, the diversity of organic compounds of KW was the most dominant factor that affected the potential MYs of KW. The effect of the C/N and C/P ratios or the concentration of metal ions was insignificant. Two typical methods to calculate the theoretical MY (TMY) were compared, the organic composition method can simulate methane production more precisely than the elemental analysis method. Significant linear correlations were found between TMYorg and MYs under mesophilic and thermophilic conditions. The organic composition method can thus be utilized as a fast technique to predict the methane production potential of KW.

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

    PubMed

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

    2015-01-01

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

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

    PubMed

    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.

  4. Isolation and characterization of an H/sub 2/-oxidizing thermophilic methanogen

    SciTech Connect

    Ferguson, T.J.; Mah, R.A.

    1983-01-01

    A thermophilic methanogen was isolated from enrichment cultures originally inoculated with sludge from an anaerobic kelp digester (55 degrees C). This isolate exhibited a temperature optimum of 55 to 60 degrees C and a maximum near 70 degrees C. Growth occurred throughout the pH range of 5.5 to 9.0, with optimal growth near pH 7.2. Altough 4% salt was present in the isolation medium, salt was not required for optimal growth. The thermophile utilized formate or H/sub 2/CO/sub 2/ but not acetate, methanol, or methylamines for growth and methanogenesis. Growth in complex medium was very rapid, and a minimum doubling time of 1.8 hours was recorded in media supplemented with rumen fluid. Growth in defined media required the addition of acetate and an unknown factor(s) from digester supernatant, rumen fluid, or Trypticase. Cells in liquid culture were oval to coccoid, 0.7 to 1.8 ..mu.. meters in diameter, often occurring in pairs. The cells were easily lysed upon exposure to oxygen or 0.08 mg of sodium dodecyl sulfate per ml. The isolate was sensitive to tetracycline and chloramphenicol but not penicillin G or cycloserine. The DNA base composition was 59.69 mol% guanine plus cytosine. (Refs. 34).

  5. Enhancing thermophilic co-digestion of nitrogen-rich substrates by air side-stream stripping.

    PubMed

    Pedizzi, Chiara; Lema, Juan M; Carballa, Marta

    2017-10-01

    High ammonia concentrations can inhibit thermophilic anaerobic digestion, thus limiting the advantageous treatment of wastes rich both in carbon and nitrogen. In the present paper, an air side-stream stripping column was coupled to two thermophilic digesters to control ammonia content. The effects of exposing an increasing biomass fraction to the harsh conditions inside the column (pH above 9, O2 at saturation and high T) on digester performance were tested by treating and recirculating 21% of reactor volume 3 or 5 times per week. Neither biomass/liquid separation before stripping nor addition of chemicals to control pH were required. Ammonium nitrogen concentration was lowered from 2.4 to 1.1±0.1gN-TANL(-1) and from 4.5 to 2.0±0.1gN-TANL(-1) without compromising process stability. The air side-stream stripping process was successfully implemented to maintain ammonia concentration below 0.6±0.1gN-NH3L(-1) while boosting methane production by doubling organic (and therefore nitrogen) loading rate. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    PubMed

    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.

  7. Ultrastructure and extreme heat resistance of spores from thermophilic Clostridium species.

    PubMed Central

    Hyun, H H; Zeikus, J G; Longin, R; Millet, J; Ryter, A

    1983-01-01

    The heat resistance and ultrastructural features of spore suspensions prepared from Clostridium thermocellum LQRI, Clostridium thermosulfurogenes 4B, and Clostridium thermohydrosulfuricum 39E were compared as a function of decimal reduction time. The decimal reduction times at 121 degrees C for strains LQRI, 4B, and 39E were 0.5, 2.5, and 11 min. The higher degree of spore heat resistance was associated with a spore architecture displaying a thicker cortex layer. Heat resistance of these spores was proportional to the ratio of spore cortex volume to cytoplasmic volume. These ratios for spores of strains LQRI, 4B, and 39E were 1.4, 1.6, and 6.6, respectively. The extreme heat resistance and autoclavable nature of C. thermohydrosulfuricum spores under routine sterilization procedures is suggested as a common cause of laboratory contamination with pure cultures of thermophilic, saccharide-fermenting anaerobes. Images PMID:6643392

  8. Microwave effects on soluble substrate and thermophilic digestibility of activated sludge.

    PubMed

    Coelho, Nuno Miguel Gabriel; Droste, Ronald L; Kennedy, Kevin J

    2014-03-01

    Thickened waste-activated sludge (TWAS) was subjected to microwave pretreatment and athermal irradiation. The soluble phase of each type of TWAS pretreatment was subject to ultrafiltration in series using progressively smaller pore-size membranes (300, 100, 10, and 1 kDa) and biodegradability tests. Microwave pretreatment solubilizes a considerable amount of the suspended organic substrate, but athermal irradiation also causes solubilization of organic matter, although at a smaller scale than microwave. Proteins are particularly sensitive to athermal irradiation, and both microwave and athermal irradiation are capable of changing the size distribution of dissolved organic matter. Athermal irradiation and microwave have a substantially different effect on thermophilic anaerobic biodegradability of the various size fractions obtained after ultrafiltration. Slight inhibition and decrease in total biogas production was measured in some microwave tests. Athermal irradiation does not cause a decrease in maximum biogas production rate in any test and increases slightly biogas production.

  9. Complete genome sequence of the thermophilic sulfur-reducer Hippea maritima type strain (MH(2)).

    PubMed

    Huntemann, Marcel; Lu, Megan; Nolan, Matt; Lapidus, Alla; Lucas, Susan; Hammon, Nancy; Deshpande, Shweta; Cheng, Jan-Fang; Tapia, Roxanne; Han, Cliff; Goodwin, Lynne; Pitluck, Sam; Liolios, Konstantinos; Pagani, Ioanna; Ivanova, Natalia; Ovchinikova, Galina; Pati, Amrita; Chen, Amy; Palaniappan, Krishna; Land, Miriam; Hauser, Loren; Jeffries, Cynthia D; Detter, John C; Brambilla, Evelyne-Marie; Rohde, Manfred; Spring, Stefan; Göker, Markus; Woyke, Tanja; Bristow, James; Eisen, Jonathan A; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C; Klenk, Hans-Peter; Mavromatis, Konstantinos

    2011-07-01

    Hippea maritima (Miroshnichenko et al. 1999) is the type species of the genus Hippea, which belongs to the family Desulfurellaceae within the class Deltaproteobacteria. The anaerobic, moderately thermophilic marine sulfur-reducer was first isolated from shallow-water hot vents in Matipur Harbor, Papua New Guinea. H. maritima was of interest for genome sequencing because of its isolated phylogenetic location, as a distant next neighbor of the genus Desulfurella. Strain MH(2) (T) is the first type strain from the order Desulfurellales with a completely sequenced genome. The 1,694,430 bp long linear genome with its 1,723 protein-coding and 57 RNA genes consists of one circular chromosome and is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

  10. Predominant contribution of syntrophic acetate oxidation to thermophilic methane formation at high acetate concentrations.

    PubMed

    Hao, Li-Ping; Lü, Fan; He, Pin-Jing; Li, Lei; Shao, Li-Ming

    2011-01-15

    To quantify the contribution of syntrophic acetate oxidation to thermophilic anaerobic methanogenesis under the stressed condition induced by acidification, the methanogenic conversion process of 100 mmol/L acetate was monitored simultaneously by using isotopic tracing and selective inhibition techniques, supplemented with the analysis of unculturable microorganisms. Both quantitative methods demonstrated that, in the presence of aceticlastic and hydrogenotrophic methanogens, a large percentage of methane (up to 89%) was initially derived from CO(2) reduction, indicating the predominant contribution of the syntrophic acetate oxidation pathway to acetate degradation at high acid concentrations. A temporal decrease of the fraction of hydrogenotrophic methanogenesis from more than 60% to less than 40% reflected the gradual prevalence of the aceticlastic methanogenesis pathway along with the reduction of acetate. This apparent discrimination of acetate methanization pathways highlighted the importance of the syntrophic acetate-oxidizing bacteria to initialize methanogenesis from high organic loadings.

  11. Horse manure as feedstock for anaerobic digestion.

    PubMed

    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.

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

    PubMed

    Luo, Gang; Angelidaki, Irini

    2012-11-01

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

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

    PubMed

    Blumensaat, F; Keller, J

    2005-01-01

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

  14. Diversity of thermophilic and non-thermophilic Crenarchaeota at 80 degrees C.

    PubMed

    Kvist, Thomas; Mengewein, Anett; Manzei, Stefanie; Ahring, Birgitte K; Westermann, Peter

    2005-03-01

    A hot spring in the solfataric field of Pisciarelli (Naples-Italy) was analysed for Archaeal diversity. Total DNA was extracted from the environment, archaeal 16S rRNA genes were amplified with Archaea specific primers, and a clone library consisting of 201 clones was established. The clones were grouped in 10 different groups each representing a specific band pattern using restriction fragment length polymorphism (RFLP). Members of all 10 groups were sequenced and phylogenetically analyzed. Surprisingly, a high abundance of clones belonging to non-thermophilic Crenarchaeal clusters were detected together with the thermophilic archaeon Acidianus infernus in this thermophilic environment. Neither Sulfolobus species nor other hyperthermophilic Crenarchaeota were detected in the clone library. The relative abundance of the sequenced clones was confirmed by terminal restriction fragment analyses. Amplification of 16S rRNA genes from Archaea transferred from the surrounding environment was considered negligible because DNA from non-thermophilic Crenarchaeota incubated under conditions similar to the solfatara could not be PCR amplified after 5 min.

  15. Paraquat toxicity and effect of hydrogen peroxide on thermophilic bacteria.

    PubMed

    Allgood, G S; Perry, J J

    1985-01-01

    Paraquat (PQ++) increased cyanide-resistant univalent respiration in cell suspensions of five strains of obligately thermophilic bacteria. PQ++ was reduced by an NADH: or NADPH:paraquat diaphorase and selectivity for NADH, NADPH, or both electron donors varied among the thermophiles. Superoxide anion production that was dependent on the presence of PQ++ was shown by following the superoxide dismutase-inhibitable reduction of cytochrome c. In addition, the PQ++-dependent formation of hydrogen peroxide from superoxide anion was evident in two of the thermophilic strains. Catalase synthesis was induced by adding hydrogen peroxide to the growth medium of the thermophiles. The induction of catalase to eliminate hydrogen peroxide appears to be an important response of these thermophilic bacteria to oxygen toxicity.

  16. Effects of process stability on anaerobic biodegradation of LAS in UASB reactors.

    PubMed

    Løbner, Trine; Toräng, Lars; Batstone, Damien John; Schmidt, Jens Ejbye; Angelidaki, Irini

    2005-03-30

    Anaerobic biodegradation of linear alkylbenzene sulfonates (LAS) was studied in upflow anaerobic sludge blanket (UASB) reactors operated under mesophilic (37 degrees C) and thermophilic (55 degrees C) conditions. LAS C12 concentration in the influents was 10 mg.L(-1), and the hydraulic retention time in the reactors was 2 days. Adsorption of LAS C1