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

Science.gov (United States)

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

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

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

KAUST Repository

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

2017-01-01

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

Microbiological Hydrogen Production by Anaerobic Fermentation and Photosynthetic Process

International Nuclear Information System (INIS)

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

2009-01-01

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

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

DEFF Research Database (Denmark)

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

2013-01-01

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

Production of Bioethanol From Lignocellulosic Biomass Using Thermophilic Anaerobic Bacteria

DEFF Research Database (Denmark)

Georgieva, Tania I.

2006-01-01

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

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

DEFF Research Database (Denmark)

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

2003-01-01

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

Azo dye reduction by mesophilic and thermophilic anaerobic consortia

NARCIS (Netherlands)

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

2005-01-01

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

Mesophilic and thermophilic anaerobic digestion of sulphate-containing wastewaters.

Science.gov (United States)

Colleran, E; Pender, S

2002-01-01

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

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

Science.gov (United States)

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

2014-09-01

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

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

DEFF Research Database (Denmark)

Kostesha, Natalie; Willquist, Karin; Emnéus, Jenny

2011-01-01

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

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

Science.gov (United States)

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

2018-01-01

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

Design of A solar Thermophilic Anaerobic Reactor for Small Farms

NARCIS (Netherlands)

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

2004-01-01

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

Thermophilic anaerobic acetate-utilizing methanogens and their metabolism

DEFF Research Database (Denmark)

Mladenovska, Zuzana

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

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

NARCIS (Netherlands)

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

2005-01-01

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

Evaluation of ethanol productivity from cellulose by Clostridium thermocellum

Energy Technology Data Exchange (ETDEWEB)

Kurose, N; Yagyu, J; Miyazaki, T; Uchida, M; Hanai, S; Obayashi, A

1986-01-01

Clostridium thermocellum, a thermophilic anaerobe, directly converts cellulose to EtOH. To estimate its EtOH production from cellulose, we used a new method based on material balance by which the efficiencies of the enzymes that convert cellulose to ethanol were calculated. Using this method, the maximum efficiency of ethanol production of two strains of C. thermocellum was estimated to be 0.05, with 0.67 as the theoretical maximum. 3 references.

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

NARCIS (Netherlands)

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

2013-01-01

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

Start-up strategies for thermophilic anaerobic digestion of pig manure

International Nuclear Information System (INIS)

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

2014-01-01

Sludge physicochemical composition, methane (CH 4 ) yield, and methanogenic community structure and dynamics using quantitative real-time polymerase chain reaction were determined after start-up of anaerobic digestion of pig manure. Eight thermophilic continuous stirred anaerobic digesters were used during 126 days. Four management strategies were investigated: a feedless and a non-feedless period followed by a gradual or an abrupt addition of pig manure (two digesters per strategy). During the first 43 days, VFA (volatile fatty acids) accumulations and low CH 4 yield were observed in all digesters. After this period, digesters recovered their initial status being propionic acid the last parameter to be re-established. Non-feedless digesters with an abrupt addition of pig manure showed the best performances (lower VFA accumulation and higher CH 4 yield). Differences in microbial orders and dynamics, however, were less evident among treatments. Hydrogenotrophic methanogenesis, Methanomicrobiales first and Methanobacteriales second, was the dominant metabolic pathway in all digesters. Further research is needed to clarify the role and activity of hydrogenotrophic methanogens during the recovery start-up period and to identify the best molecular tools and methodologies to monitor microbial populations and dynamics reliably and accurately in anaerobic digesters. - Highlights: • Four start-up strategies for thermophilic anaerobic digestion of pig manure were tested. • Physicochemical composition, methane yield and methanogenic community were determined. • During the first 43 days, a decline in reactor's performance occurred. • The best start-up strategy was non-feedless with an abrupt addition of pig slurry. • Hydrogenotrophic methanogenesis was the dominant metabolic pathway

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

NARCIS (Netherlands)

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

2002-01-01

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

Startup and stability of thermophilic anaerobic digestion of OFMSW

KAUST Repository

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

2013-01-01

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

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

Science.gov (United States)

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

2014-10-01

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

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

Science.gov (United States)

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

2012-04-01

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

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

Science.gov (United States)

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

2013-12-01

Thermophilic (55 °C) anaerobic microbial communities were enriched with a synthetic syngas mixture (composed of CO, H2 , and CO2 ) or with CO alone. Cultures T-Syn and T-CO were incubated and successively transferred with syngas (16 transfers) or CO (9 transfers), respectively, with increasing CO partial pressures from 0.09 to 0.88 bar. Culture T-Syn, after 4 successive transfers with syngas, was also incubated with CO and subsequently transferred (9 transfers) with solely this substrate - cultures T-Syn-CO. Incubation with syngas and CO caused a rapid decrease in the microbial diversity of the anaerobic consortium. T-Syn and T-Syn-CO showed identical microbial composition and were dominated by Desulfotomaculum and Caloribacterium species. Incubation initiated with CO resulted in the enrichment of bacteria from the genera Thermincola and Thermoanaerobacter. Methane was detected in the first two to three transfers of T-Syn, but production ceased afterward. Acetate was the main product formed by T-Syn and T-Syn-CO. Enriched T-CO cultures showed a two-phase conversion, in which H2 was formed first and then converted to acetate. This research provides insight into how thermophilic anaerobic communities develop using syngas/CO as sole energy and carbon source can be steered for specific end products and subsequent microbial synthesis of chemicals. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

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

Science.gov (United States)

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

2015-04-15

A combined mesophilic anaerobic-thermophilic aerobic process was used to treat high-strength food wastewater in this study. During the experimental period, most of solid residue from the mesophilic anaerobic reactor (R1) was separated by centrifugation and introduced into the thermophilic aerobic reactor (R2) for further digestion. Then, thermophilic aerobically-digested sludge was reintroduced into R1 to enhance reactor performance. The combined process was operated with two different Runs: Run I with hydraulic retention time (HRT) = 40 d (corresponding OLR = 3.5 kg COD/m(3) d) and Run II with HRT = 20 d (corresponding OLR = 7 kg COD/m(3)). For a comparison, a single-stage mesophilic anaerobic reactor (R3) was operated concurrently with same OLRs and HRTs as the combined process. During the overall digestion, all reactors showed high stability without pH control. The combined process demonstrated significantly higher organic matter removal efficiencies (over 90%) of TS, VS and COD and methane production than did R3. Quantitative real-time PCR (qPCR) results indicated that higher populations of both bacteria and archaea were maintained in R1 than in R3. Pyrosequencing analysis revealed relatively high abundance of phylum Actinobacteria in both R1 and R2, and a predominance of phyla Synergistetes and Firmicutes in R3 during Run II. Furthermore, R1 and R2 shared genera (Prevotella, Aminobacterium, Geobacillus and Unclassified Actinobacteria), which suggests synergy between mesophilic anaerobic digestion and thermophilic aerobic digestion. For archaea, in R1 methanogenic archaea shifted from genus Methanosaeta to Methanosarcina, whereas genera Methanosaeta, Methanobacterium and Methanoculleus were predominant in R3. The results demonstrated dynamics of key microbial populations that were highly consistent with an enhanced reactor performance of the combined process. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

2015-10-19

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

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

Science.gov (United States)

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

2018-01-15

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

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

Science.gov (United States)

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

2014-01-01

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

Cellulolytic properties of an extremely thermophilic anaerobe

Energy Technology Data Exchange (ETDEWEB)

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

1990-09-01

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

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

DEFF Research Database (Denmark)

Hartmann, H.; Ahring, Birgitte Kiær

2005-01-01

A novel reactor configuration was investigated for anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW). An anaerobic hyper-thermophilic (68°C) reactor R68 was implemented as a post–treatment step for the effluent of a thermophilic reactor R1 (55°C) in order to enhance...... hydrolysis of recalcitrant organic matter, improve sanitation and ease the stripping of ammonia from the reactor. The efficiency of the combined system was studied in terms of methane yield, volatile solids (VS) reduction and volatile fatty acid (VFA) production at different hydraulic retention times (HRT...

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

DEFF Research Database (Denmark)

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

2009-01-01

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

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

Science.gov (United States)

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

2010-10-01

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

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

International Nuclear Information System (INIS)

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

2010-01-01

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

Syntrophic co-culture of aerobic Bacillus and anaerobic Clostridium for bio-fuels and bio-hydrogen production

Energy Technology Data Exchange (ETDEWEB)

Chang, Jui-Jen; Ho, Cheng-Yu.; Chen, Wei-En; Huang, Chieh-Chen [Department of Life Sciences, National Chung Hsing University, Taichung (China); Chou, Chia-Hung; Lay, Jiunn-Jyi [Department of Science and Technology, National Kaohsiung First University, Kaohsiung (China)

2008-10-15

By using brewery yeast waste and microflora from rice straw compost, an anaerobic semi-solid bio-hydrogen-producing system has been established. For the purpose of industrialization, the major players of both aerobic and anaerobic bacterial strains in the system were isolated and their combination for an effective production of bio-hydrogen and other bio-fuels was examined in this study. The phylogenetic analysis found that four anaerobic isolates (Clostridium beijerinckii L9, Clostridium diolis Z2, Clostridium roseum Z5-1, and C. roseum W8) were highly related with each other and belongs to the cluster I clostridia family, the family that many of solvent-producing strains included. On the other hand, one of the aerobic isolates, the Bacillus thermoamylovorans strain I, shown multiple extracellular enzyme activities including lipase, protease, {alpha}-amylase, pectinase and cellulase, was suggested as a good partner for creating an anaerobic environment and pre-saccharification of substrate for those co-cultured solventogenic clostridial strain. Among these clostridial strains, though C. beijerinckii L9 do not show as many extracellular enzyme activities as Bacillus, but it performs the highest hydrogen-producing ability. The original microflora can be updated to a syntrophic bacterial co-culture system contended only with B. thermoamylovorans I and C. beijerinckii L9. The combination of aerobic Bacillus and anaerobic Clostridium may play the key role for developing the industrialized bio-fuels and bio-hydrogen-producing system from biomass. (author)

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

NARCIS (Netherlands)

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

2002-01-01

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

High ethanol tolerance of the thermophilic anaerobic ethanol producer Thermoanaerobacter BG1L1

DEFF Research Database (Denmark)

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

2007-01-01

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

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

Science.gov (United States)

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

2017-12-01

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

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

Science.gov (United States)

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

2015-12-01

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

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

DEFF Research Database (Denmark)

Johansen, Anders; Bangsø Nielsen, Henrik; Hansen, Christian M.

2013-01-01

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

Thermophilic slurry-phase treatment of petroleum hydrocarbon waste sludges

International Nuclear Information System (INIS)

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

1995-01-01

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

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

Science.gov (United States)

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

2007-03-01

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

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

DEFF Research Database (Denmark)

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

1995-01-01

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

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

DEFF Research Database (Denmark)

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

1996-01-01

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

Ethanol production by Clostridium thermocellum grown on hydrothermally and organosolv-pretreated lignocellulosic materials

Energy Technology Data Exchange (ETDEWEB)

Hoermeyer, H F; Bonn, G; Bobleter, O; Tailliez, P; Millet, J; Girard, H; Aubert, J P

1988-12-01

Two strains of the thermophilic anaerobe Clostridium thermocellum, the wild type NCIB 10682 and its ethanol-hyperproductive mutant 647, were tested for their ability to grow on natural lignocellulosic materials (poplar wood, wheat straw) which had been pretreated by either hydrothermolysis or an organosolv process. For both materials and both strains, the dependencies of substrate accessibility on the pretreatment temperature were established in terms of cellulose hydrolysis and of product formation. In addition to the non-pH-controlled shake flask assays, in vitro experiments with cell-free culture supernatant and in vivo cellulolyses under pH regulation in a laboratory fermenter indicated that lignocellulosics pretreated at approx. 230/sup 0/C were degraded efficiently by the Clostridium strains investigated.

Biological hydrogen production by moderately thermophilic anaerobic bacteria

International Nuclear Information System (INIS)

HP Goorissen; AJM Stams

2006-01-01

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

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

Science.gov (United States)

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

2018-05-01

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

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

Science.gov (United States)

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

2015-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1990-08-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1984-01-01

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

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

Science.gov (United States)

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

2010-11-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Sommer, Peter

1998-02-01

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

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

Science.gov (United States)

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

2017-10-01

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

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

Science.gov (United States)

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

2013-02-28

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-12-15

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

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

NARCIS (Netherlands)

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

2006-01-01

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

Hydrolytic bacteria in mesophilic and thermophilic degradation of plant biomass

Energy Technology Data Exchange (ETDEWEB)

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

2010-12-15

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

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

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-05-01

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

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

International Nuclear Information System (INIS)

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

2004-01-01

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

Thermophilic anaerobic oxidation of methane by marine microbial consortia.

Science.gov (United States)

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

2011-12-01

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

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

Science.gov (United States)

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

2013-02-01

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

Performance optimization and validation of ADM1 simulations under anaerobic thermophilic conditions

KAUST Repository

Atallah, Nabil M.

2014-12-01

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

Performance optimization and validation of ADM1 simulations under anaerobic thermophilic conditions

KAUST Repository

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

2014-01-01

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

Atmospheric vs. anaerobic processing of metabolome samples for the metabolite profiling of a strict anaerobic bacterium, Clostridium acetobutylicum.

Science.gov (United States)

Lee, Sang-Hyun; Kim, Sooah; Kwon, Min-A; Jung, Young Hoon; Shin, Yong-An; Kim, Kyoung Heon

2014-12-01

Well-established metabolome sample preparation is a prerequisite for reliable metabolomic data. For metabolome sampling of a Gram-positive strict anaerobe, Clostridium acetobutylicum, fast filtration and metabolite extraction with acetonitrile/methanol/water (2:2:1, v/v) at -20°C under anaerobic conditions has been commonly used. This anaerobic metabolite processing method is laborious and time-consuming since it is conducted in an anaerobic chamber. Also, there have not been any systematic method evaluation and development of metabolome sample preparation for strict anaerobes and Gram-positive bacteria. In this study, metabolome sampling and extraction methods were rigorously evaluated and optimized for C. acetobutylicum by using gas chromatography/time-of-flight mass spectrometry-based metabolomics, in which a total of 116 metabolites were identified. When comparing the atmospheric (i.e., in air) and anaerobic (i.e., in an anaerobic chamber) processing of metabolome sample preparation, there was no significant difference in the quality and quantity of the metabolomic data. For metabolite extraction, pure methanol at -20°C was a better solvent than acetonitrile/methanol/water (2:2:1, v/v/v) at -20°C that is frequently used for C. acetobutylicum, and metabolite profiles were significantly different depending on extraction solvents. This is the first evaluation of metabolite sample preparation under aerobic processing conditions for an anaerobe. This method could be applied conveniently, efficiently, and reliably to metabolome analysis for strict anaerobes in air. © 2014 Wiley Periodicals, Inc.

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

Science.gov (United States)

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

2012-03-01

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

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

International Nuclear Information System (INIS)

Yang, Yingnan; Tsukahara, Kenichiro; Sawayama, Shigeki

2007-01-01

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

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

Science.gov (United States)

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

2014-12-01

In this study, two experimental sets of data each involving two thermophilic anaerobic digesters treating food waste, were simulated using the Anaerobic Digestion Model No. 1 (ADM1). A sensitivity analysis was conducted, using both data sets of one digester, for parameter optimization based on five measured performance indicators: methane generation, pH, acetate, total COD, ammonia, and an equally weighted combination of the five indicators. The simulation results revealed that while optimization with respect to methane alone, a commonly adopted approach, succeeded in simulating methane experimental results, it predicted other intermediary outputs less accurately. On the other hand, the multi-objective optimization has the advantage of providing better results than methane optimization despite not capturing the intermediary output. The results from the parameter optimization were validated upon their independent application on the data sets of the second digester. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

2017-01-01

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

Ecology and biotechnological potential of the thermophilic fermentative Coprothermobacter spp.

Science.gov (United States)

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

2015-05-01

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

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

NARCIS (Netherlands)

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

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

Biohydrogen production by anaerobic fermentation of waste. Final project report

Energy Technology Data Exchange (ETDEWEB)

Karakashev, D.; Angelidaki, I.

2009-01-15

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

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

Directory of Open Access Journals (Sweden)

I Irvan

2012-04-01

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

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

DEFF Research Database (Denmark)

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

2003-01-01

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

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

International Nuclear Information System (INIS)

Zamalloa, Carlos; Boon, Nico; Verstraete, Willy

2012-01-01

Highlights: ► We investigate the digestion of two algae biomasses in hybrid flow-through reactors. ► We determine the bio-methane potential of these biomasses through batch assays. ► Conversion efficiencies of 20–50% with an HRT of 2.2 days are possible. ► We valorise microalgae biomass by anaerobic digestion in a high rate reactor. -- Abstract: Two types of non-axenic algal cultures, one dominated by the freshwater microalgae Scenedesmus obliquus and the other by the marine microalgae Phaeodactylum tricornutum, were cultivated in two types of simple photobioreactor systems. The production rates, expressed on dry matter (DM) basis, were in the order of 0.12 and 0.18 g DM L −1 d −1 for S. obliquus and P. tricornutum respectively. The biogas potential of algal biomass was assessed by performing standardized batch digestion as well as digestion in a hybrid flow-through reactor (combining a sludge blanket and a carrier bed), the latter under mesophilic and thermophilic conditions. Biomethane potential assays revealed the ultimate methane yield (B 0 ) of P. tricornutum biomass to be about a factor of 1.5 higher than that of S. obliquus biomass, i.e. 0.36 and 0.24 L CH 4 g −1 volatile solids (VS) added respectively. For S. obliquus biomass, the hybrid flow-through reactor tests operated at volumetric organic loading rate (Bv) of 2.8 gVS L −1 d −1 indicated low conversion efficiencies ranging between 26–31% at a hydraulic retention time (HRT) of 2.2 days for mesophilic and thermophilic conditions respectively. When digesting P. tricornutum at a Bv of 1.9 gVS L −1 d −1 at either mesophilic or thermophilic conditions and at an HRT of 2.2 days, an overall conversion efficiency of about 50% was obtained. This work indicated that the hydrolysis of the algae cells is limiting the anaerobic processing of intensively grown S. obliquus and P. tricornutum biomass.

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

Science.gov (United States)

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

2018-07-01

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

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

DEFF Research Database (Denmark)

Mogensen, Anders Skibsted; Ahring, Birgitte Kiær

2002-01-01

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

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

KAUST Repository

Ghanimeh, Sophia

2017-05-30

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

Clostridium punense sp. nov., an obligate anaerobe isolated from healthy human faeces.

Science.gov (United States)

Lanjekar, Vikram Bholanath; Marathe, Nachiket Prakash; Shouche, Yogesh Shreepad; Ranade, Dilip Ramchandra

2015-12-01

An obligately anaerobic, rod-shaped (0.5-1.0 × 2.0-10.0 μm), Gram-stain-positive bacterium, occurring mainly singly or in pairs, and designated BLPYG-8T, was isolated from faeces of a healthy human volunteer aged 56 years. Cells were non-motile. Oval, terminal spores were formed that swell the cells. The strain was affiliated with the genus Clostridium sensu stricto (Clostridium rRNA cluster I) as revealed by 16S rRNA gene sequence analysis. Strain BLPYG-8T showed 97.3 to 97.4 % 16S rRNA gene sequence similarity with Clostridium sulfidigenes DSM 18982T, Clostridium subterminale DSM 6970T and Clostridium thiosulfatireducens DSM 13105T. DNA-DNA hybridization and phenotypic analysis showed that the strain was distinct from its closest relatives, C. sulfidigenes DSM 18982T, C. subterminale DSM 6970T, C. thiosulfatireducens DSM 13105T with 54.2, 53.9 and 53.3 % DNA-DNA relatedness, respectively. Strain BLPYG-8T grew in PYG broth at temperatures between 20 and 40 °C (optimum 37 °C). The strain utilized a range of amino acids as well as carbohydrates as a source of carbon and energy. Glucose fermentation resulted in the formation of volatile fatty acids mainly acetic acid, n-butyric acid and organic acids such as succinic and lactic acid. The DNA G+C content of strain BLPYG-8T was 44.1 mol%. The major fatty acids (>10 %) were C14 : 0, iso-C15 : 0, C16 : 1ω7c and C16 : 0. Phylogenetic analysis and specific phenotypic characteristics and/or DNA G+C content differentiated the strain from its closest relatives. On the basis of these data, strain BLPYG-8T represents a novel species of the genus Clostridium, for which the name Clostridium punense sp. nov. is proposed. The type strain is BLPYG-8T ( = DSM 28650T = CCUG 64195T = MCC 2737T).

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

Science.gov (United States)

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

2011-04-01

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

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

Science.gov (United States)

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

2010-06-01

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

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

DEFF Research Database (Denmark)

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

2008-01-01

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

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

Science.gov (United States)

Cheng, Xi-Yu; Liu, Chun-Zhao

2012-01-01

A three-stage anaerobic fermentation process including H(2) fermentation I, H(2) fermentation II, methane fermentation was developed for the coproduction of hydrogen and methane from cornstalks. Hydrogen production from cornstalks using direct microbial conversion by Clostridium thermocellum 7072 was markedly enhanced in the two-stage thermophilic hydrogen fermentation process integrated with alkaline treatment. The highest total hydrogen yield from cornstalks in the two-stage fermentation process reached 74.4 mL/g-cornstalk. The hydrogen fermentation effluents and alkaline hydrolyzate were further used for methane fermentation by anaerobic granular sludge, and the total methane yield reached 205.8 mL/g-cornstalk. The total energy recovery in the three-stage anaerobic fermentation process integrated with alkaline hydrolysis reached 70.0%. Copyright © 2011 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

2017-03-15

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

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

OpenAIRE

Henstra, Anne M.; Stams, Alfons J. M.

2011-01-01

Carboxydothermus hydrogenoformans is a thermophilic strictly anaerobic bacterium that catalyses the water gas shift reaction, the conversion of carbon monoxide with water to molecular hydrogen and carbon dioxide. The thermodynamically favorable growth temperature, compared to existing industrial catalytic processes, makes this organism an interesting alternative for production of cheap hydrogen gas suitable to fuel CO-sensitive fuel cells in a future hydrogen economy, provided sufficiently lo...

Conductive iron oxides accelerate thermophilic methanogenesis from acetate and propionate.

Science.gov (United States)

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

2015-06-01

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

Assessing Methanobrevibacter smithii and Clostridium difficile as not conventional faecal indicators in effluents of a wastewater treatment plant integrated with sludge anaerobic digestion.

Science.gov (United States)

Romanazzi, Valeria; Bonetta, Silvia; Fornasero, Stefania; De Ceglia, Margherita; Gilli, Giorgio; Traversi, Deborah

2016-12-15

Wastewater treatment plants (WWTP) are an important source of surface water contamination by enteric pathogens, affecting the role of environmental water as a microbial reservoir. We describe the release to the environment of certain anaerobes of human and environmental concern. The work was focused on emerging microbial targets. They are tracing, by RT-qPCR, on WWTP effluents, both liquid and solid, when an anaerobic digestion step is included. The focus is placed on Clostridium spp. with the specific quantification of Clostridium perfringens, as typical bioindicator, and Clostridium difficile, as emerging pathogen not only confined into nosocomial infection. Moreover methanogens were quantified for their involvement in the anaerobic digestion, and in particular on Methanobrevibacter smithii as major methanogenic component of the human gut microbiome and as not conventional faecal indicator. In the water samples, a reduction, statistically significant, in all microbial targets was observed (p effluents, particularly bio-solids, to reduce the potential release of pathogens into the environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

DEFF Research Database (Denmark)

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

2011-01-01

Hydrogen production from desugared molasses (DM) was investigated in both batch and continuous reactors using thermophilic mixed cultures enriched from digested manure by load shock (loading with DM concentration of 50.1 g-sugar/L) to suppress methanogens. H2 gas, free of methane, was produced......) and Thermoanaerobacterium thermosaccharolyticum with a relative abundance of 36%, 27%, and 10% of total microorganisms, respectively. This study shows that hydrogen production could be efficiently facilitated by using anaerobic granules as a carrier, where microbes from mixed culture enriched in the DM batch cultivation....... The enriched hydrogen producing mixed culture achieved from the 16.7 g-sugars/L DM batch cultivation was immobilized on heat treated anaerobic sludge granules in an up-flow anaerobic sludge blanket (UASB) reactor. The UASB reactor, operated at a hydraulic retention time (HRT) of 24 h fed with 16.7 g...

Thermophilic lignocellulose deconstruction.

Science.gov (United States)

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

2014-05-01

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

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

Science.gov (United States)

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

2011-01-01

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

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

Science.gov (United States)

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

2006-10-01

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

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

Science.gov (United States)

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

2010-04-01

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

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

International Nuclear Information System (INIS)

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

2014-01-01

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

Evolution of microorganisms in thermophilic-dry anaerobic digestion.

Science.gov (United States)

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

2008-05-01

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

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

Science.gov (United States)

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

2001-01-01

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

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

KAUST Repository

Ghanimeh, Sophia A.

2013-03-01

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

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

KAUST Repository

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

2013-01-01

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

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

Science.gov (United States)

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

2016-07-01

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

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

NARCIS (Netherlands)

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

2004-01-01

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

Modeling temperature variations in a pilot plant thermophilic anaerobic digester.

Science.gov (United States)

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

2011-05-01

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

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

Science.gov (United States)

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

2013-04-01

Anaerobic digestion of residual materials from animals and crops offers an opportunity to simultaneously produce bioenergy and plant fertilizers at single farms and in farm communities where input substrate materials and resulting digested residues are shared among member farms. A surplus benefit from this practice may be the suppressing of propagules from harmful biological pests like weeds and animal pathogens (e.g. parasites). In the present work, batch experiments were performed, where survival of seeds of seven species of weeds and non-embryonated eggs of the large roundworm of pigs, Ascaris suum, was assessed under conditions similar to biogas plants managed at meso- (37°C) and thermophilic (55°C) conditions. Cattle manure was used as digestion substrate and experimental units were sampled destructively over time. Regarding weed seeds, the effect of thermophilic conditions (55°C) was very clear as complete mortality, irrespective of weed species, was reached after less than 2 days. At mesophilic conditions, seeds of Avena fatua, Sinapsis arvensis, Solidago canadensis had completely lost germination ability, while Brassica napus, Fallopia convolvulus and Amzinckia micrantha still maintained low levels (~1%) of germination ability after 1 week. Chenopodium album was the only weed species which survived 1 week at substantial levels (7%) although after 11 d germination ability was totally lost. Similarly, at 55°C, no Ascaris eggs survived more than 3h of incubation. Incubation at 37°C did not affect egg survival during the first 48 h and it took up to 10 days before total elimination was reached. In general, anaerobic digestion in biogas plants seems an efficient way (thermophilic more efficient than mesophilic) to treat organic farm wastes in a way that suppresses animal parasites and weeds so that the digestates can be applied without risking spread of these pests. Copyright © 2012 Elsevier Ltd. All rights reserved.

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

DEFF Research Database (Denmark)

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

2004-01-01

The nucleotide sequence of two novel plasmids isolated from the extreme thermophilic anaerobic bacterium Anaerocellum thermophilum DSM6725 (A. thermophilum), growing optimally at 70degreesC, has been determined. pBAS2 was found to be a 3653 bp plasmid with a GC content of 43%, and the sequence re...... with highest similarity to DNA repair protein from Campylobacter jejuni (25% aa). Orf34 showed similarity to sigma factors with highest similarity (28% aa) to the sporulation specific Sigma factor, Sigma 28(K) from Bacillus thuringiensis....

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

OpenAIRE

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

2015-01-01

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

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

Science.gov (United States)

Anjum, Reshma; Grohmann, Elisabeth; Krakat, Niclas

2017-02-01

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

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

Directory of Open Access Journals (Sweden)

Getachew D. Gebreeyessus

2016-06-01

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

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

Science.gov (United States)

Gebreeyessus, Getachew D.; Jenicek, Pavel

2016-01-01

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

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

Science.gov (United States)

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

2018-01-01

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

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

Science.gov (United States)

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

2016-09-01

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

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

Science.gov (United States)

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

2017-10-01

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

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

Science.gov (United States)

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

2006-01-01

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

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

Science.gov (United States)

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

2017-11-01

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

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

Science.gov (United States)

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

2017-08-01

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

Techniques for controlling variability in gram staining of obligate anaerobes.

Science.gov (United States)

Johnson, M J; Thatcher, E; Cox, M E

1995-01-01

Identification of anaerobes recovered from clinical samples is complicated by the fact that certain gram-positive anaerobes routinely stain gram negative; Peptostreptococcus asaccharolyticus, Eubacterium plautii, Clostridium ramosum, Clostridium symbiosum, and Clostridium clostridiiforme are among the nonconformists with regard to conventional Gram-staining procedures. Accurate Gram staining of American Type Culture Collection strains of these anaerobic bacteria is possible by implementing fixing and staining techniques within a gloveless anaerobic chamber. Under anaerobic conditions, gram-positive staining occurred in all test organisms with "quick" fixing techniques with both absolute methanol and formalin. The results support the hypothesis that, when anaerobic bacteria are exposed to oxygen, a breakdown of the physical integrity of the cell wall occurs, introducing Gram stain variability in gram-positive anaerobes. PMID:7538512

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

Science.gov (United States)

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

2017-08-01

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

Anaerobic bacteria as producers of antibiotics.

Science.gov (United States)

Behnken, Swantje; Hertweck, Christian

2012-10-01

Anaerobic bacteria are the oldest terrestrial creatures. They occur ubiquitously in soil and in the intestine of higher organisms and play a major role in human health, ecology, and industry. However, until lately no antibiotic or any other secondary metabolite has been known from anaerobes. Mining the genome sequences of Clostridium spp. has revealed a high prevalence of putative biosynthesis genes (PKS and NRPS), and only recently the first antibiotic from the anaerobic world, closthioamide, has been isolated from the cellulose degrading bacterium Clostridium cellulolyticum. The successful genetic induction of antibiotic biosynthesis in an anaerobe encourages further investigations of obligate anaerobes to tap their hidden biosynthetic potential.

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

Science.gov (United States)

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

2017-11-01

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

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

Science.gov (United States)

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

2009-09-01

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

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

Science.gov (United States)

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

2015-01-01

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

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

DEFF Research Database (Denmark)

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

2014-01-01

A unique method was developed and applied for monitoring methanogenesis pathways based on isotope labeled substrates combined with online membrane inlet quadrupole mass spectrometry (MIMS). In our study, a fermentation sample from a full-scale biogas plant fed with pig and cattle manure, maize...... silage, and deep litter was incubated with 100 mM of [2-13C] sodium acetate under thermophilic anaerobic conditions. MIMS was used to measure the isotopic distribution of dissolved CO2 and CH4 during the degradation of acetate, while excluding interference from water by applying a cold trap. After 6 days...... a new approach for online quantification of the relative contribution of methanogenesis pathways to methane production with a time resolution shorter than one minute. The observed contribution of SAO-HM to methane production under the tested conditions challenges the current widely accepted anaerobic...

Ethanol production by anaerobic thermophilic bacteria: regulation of lactate dehydrogenase activity in Clostridium thermohydrosulfuricum

Energy Technology Data Exchange (ETDEWEB)

Germain, P; Toukourou, F; Donaduzzi, L

1986-07-01

The enzyme lactate dehydrogenase (LDH) in Clostridium thermohydrosulfuricum is controlled by the type and the concentration of the substrate. In batch fermentations an increase of the initial concentration of glucose leads to an increase in the activity of LDH. This increase in activity is related to the accumulation of fructose 1,6-diphosphate (F 1,6-DP), an intermediate of the Embden-Meyerhof-Parnas (EMP) pathway, which stimulates the enzyme by increasing its affinity for pyruvate and NADH. The Ksub(m) values of LDH for pyruvate and NADH, which are 2.5 x 10/sup -3/ M and 9.1 x 10/sup -5/ M respectively in absence of F 1,6-DP, fall considerably in the presence of this substrate. In presence of 0.2 mM of F 1,6-DP we observed a Ksub(m) of 3.3 x 10/sup -4/ M for pyruvate and 4.1 x 10/sup -5/ M for NADH.

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

Science.gov (United States)

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

2017-01-15

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

Susceptibility of anaerobic bacteria in Auckland: 1991-1996.

Science.gov (United States)

Shore, K P; Pottumarthy, S; Morris, A J

1999-11-12

To determine the antimicrobial susceptibility of local anaerobic bacteria. The antimicrobial susceptibility of 357 obligate anaerobes collected between 1991 and 1997 was determined by a standard agar dilution method. Isolates tested included Bacteroides spp. 131, Fusobacterium spp. 12, Prevotella spp. 13, Veillonella spp. 5, Clostridium perfringens 27, other Clostridium spp. 29, Propionibacterium spp. 57, Actinomyces spp. 7, other non-sporing gram-positive bacilli 28 and Peptostreptococcus spp. 48. Ten antimicrobials were tested: penicillin, amoxycillin/ clavulanic acid, pipercillin/tazobactam, ceftriaxone, cefoxitin, cefotetan, imipenem, meropenem, clindamycin and metronidazole. Imipenem, pipercillin/tazobactam, meropenem and amoxycillin/clavulanic acid were active against virtually all anaerobes tested. Metronidazole was active against all anaerobic gram-negative bacteria and Clostridium spp., but had variable activity against other anaerobes. Cefoxitin was the most active cephalosporin against Bacteroides spp., with 76%, 64% and 15% of Bacteroides spp. being susceptible to cefoxitin, cefotetan and ceftriaxone, respectively. Penicillin had poor activity against anaerobic gram negative bacilli. Actinomyces and Propionibacterium spp. were susceptible to all antimicrobials tested except metronidazole. Variable results were obtained with other antimicrobial-organism combinations. Comparison of results with data from a previously published survey showed little change in susceptibility except for increased resistance of Bacteroides fragilis to ceftriaxone and Clostridium species (not C perfringens) to clindamycin. Our results update the local susceptibility profile of anaerobic bacteria and may be considered when choosing an antimicrobial agent for prophylaxis or treatment of anaerobic infections.

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

NARCIS (Netherlands)

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

2002-01-01

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

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

Science.gov (United States)

Ahring, B K; Westermann, P

1987-02-01

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

State of the art and future perspectives of thermophilic anaerobic digestion

DEFF Research Database (Denmark)

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

2002-01-01

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

Purification and properties of a thermostable pullulanase from Clostridium thermosulfurgenes EM1 which hydrolyses both. alpha. -1,6 and. alpha. -1,4-glycosidic linkages

Energy Technology Data Exchange (ETDEWEB)

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

1990-08-01

A novel thermostable pullulanase, secreted by the thermophilic anaerobic bacterium Clostridium thermosulfurogenes EM1, was purified and characterized. Applying anion exchange chromatography and gel filtration the enzyme was purified 47-fold and had a specific activity of 200 units/mg. The molecular mass of this thermostable enzyme was determined to be 102 000 daltons and consisted of a single subunit. The enzyme was able to attack specifically the {alpha}-1,6-glycosidic linkages in pullulan and caused its complete hydrolysis to maltotriose. Surprisingly and unlike the enzyme from Klebsiella pneumoniae, the purified enzyme from this anaerobic thermophile exhibited, in addition to its debranching and pullulanase activity, an {alpha}-1,4 hydrolysing activity as well. By the action of this single polypeptide chain various branched and linear polysaccharides were completely converted to two major products, namely maltose and maltotriose. The K{sub m} values of this enzyme for pullulan and amylose were determined to be 1.33 mg/ml and 0.38 mg/ml, respectively. This debranching enzyme displays a temperature optimum at 60deg-65deg C and a pH optimum at 5.5-6.0. The application of this new class of pullulanase (pullulanase type II) in industry will significantly enhance the starch saccharification process. (orig.).

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

DEFF Research Database (Denmark)

Zhu, Xinyu; Treu, Laura; Kougias, Panagiotis

2017-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2003-07-01

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

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

International Nuclear Information System (INIS)

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

2009-01-01

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

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

Science.gov (United States)

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

2013-12-01

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

Cellulolytic (cel) genes of Clostridium thermocellum F7 and the proteins encoded by them

International Nuclear Information System (INIS)

Piruzyan, E.S.; Mogutov, M.A.; Velikodvorskaya, G.A.; Pushkarskaya, T.A.

1988-01-01

This study is concerned with genes cell, ce12, and ce13 encoding the endoglucanase of the cellulolytic complex of the anaerobic thermophilic Clostridium thermocellum F7 bacteria, these genes having been closed by us earlier. The authors present the characteristics of proteins synthesized by the cel genes in the minicell system of the strain Escherichia coli K-12 X925. The molecular weights of the proteins encoded by genes cell, ce12, and ce13 are 30,000, 45,000, and 50,000 dalton, respectively. The study of the homology of the cloned section of the C. thermocellum DNA containing the endoglucanase genes, using Southern's blot-hybridization method, did not reveal their physical linkage in the genome. The authors detected a plasmid with a size of about 30 kb in the cells of the C. thermocellum F7 strain investigated

[Anaerobic bacteria isolated from patients with suspected anaerobic infections].

Science.gov (United States)

Ercis, Serpil; Tunçkanat, Ferda; Hasçelik, Gülşen

2005-10-01

The study involved 394 clinical samples sent to the Clinical Microbiology Laboratory of Hacettepe University Adult Hospital between January 1997 and May 2004 for anaerobic cultivation. Since multiple cultures from the same clinical samples of the same patient were excluded, the study was carried on 367 samples. The anaerobic cultures were performed in anaerobic jar using AnaeroGen kits (Oxoid, Basingstoke, U.K.) or GENbox (bioMérieux, Lyon, France). The isolates were identified by both classical methods and "BBL Crystal System" (Becton Dickinson, U.S.A.). While no growth was detected in 120 (32.7%) of the clinical samples studied, in 144 samples (39.2%) only aerobes, in 28 (7.6%) only anaerobes and in 75 (20.5%) of the samples both aerobes and anaerobes were isolated. The number of the anaerobic isolates was 217 from 103 samples with anaerobic growth. Of these 103 samples 15 showed single bacterial growth whereas in 88 samples multiple bacterial isolates were detected. Anaerobic isolates consisted of 92 Gram negative bacilli (Bacteroides spp. 50, Prevotella spp. 14, Porphyromonas spp. 10, Fusobacterium spp. 7, Tisierella spp. 2, unidentified 9), 57 Gram positive bacilli (Clostridium spp.17, Propionibacterium spp. 16, Lactobacillus spp. 8, Actinomyces spp. 5, Eubacterium spp. 2, Bifidobacterium adolescentis 1, Mobiluncus mulieris 1, unidentified nonspore forming rods 7), 61 Gram positive cocci (anaerobic cocci 44, microaerophilic cocci 17), and 7 Gram negative cocci (Veillonella spp.). In conclusion, in the samples studied with prediagnosis of anaerobic infection, Bacteroides spp. (23%) were the most common bacteria followed by anaerobic Gram positive cocci (20.3%) and Clostridium spp (7.8%).

Thermophilic archaea activate butane via alkyl-coenzyme M formation.

Science.gov (United States)

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

2016-11-17

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

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

Science.gov (United States)

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

2017-11-01

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

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

Science.gov (United States)

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

2017-12-01

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

Mutant alcohol dehydrogenase leads to improved ethanol tolerance in Clostridium thermocellum

Energy Technology Data Exchange (ETDEWEB)

Brown, Steven D [ORNL; Guss, Adam M [ORNL; Karpinets, Tatiana V [ORNL; Parks, Jerry M [ORNL; Smolin, Nikolai [ORNL; Yang, Shihui [ORNL; Land, Miriam L [ORNL; Klingeman, Dawn Marie [ORNL; Bhandiwad, Ashwini [Thayer School of Engineering at Dartmouth; Rodriguez, Jr., Miguel [ORNL; Raman, Babu [Dow Chemical Company, The; Shao, Xiongjun [Thayer School of Engineering at Dartmouth; Mielenz, Jonathan R [ORNL; Smith, Jeremy C [ORNL; Keller, Martin [ORNL; Lynd, Lee R [Thayer School of Engineering at Dartmouth

2011-01-01

Clostridium thermocellum is a thermophilic, obligately anaerobic, Gram-positive bacterium that is a candidate microorganism for converting cellulosic biomass into ethanol through consolidated bioprocessing. Ethanol intolerance is an important metric in terms of process economics, and tolerance has often been described as a complex and likely multigenic trait for which complex gene interactions come into play. Here, we resequence the genome of an ethanol-tolerant mutant, show that the tolerant phenotype is primarily due to a mutated bifunctional acetaldehyde-CoA/alcohol dehydrogenase gene (adhE), hypothesize based on structural analysis that cofactor specificity may be affected, and confirm this hypothesis using enzyme assays. Biochemical assays confirm a complete loss of NADH-dependent activity with concomitant acquisition of NADPH-dependent activity, which likely affects electron flow in the mutant. The simplicity of the genetic basis for the ethanol-tolerant phenotype observed here informs rational engineering of mutant microbial strains for cellulosic ethanol production.

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

Science.gov (United States)

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

2016-07-01

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

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

Science.gov (United States)

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

2016-07-22

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

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

Science.gov (United States)

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

2017-12-01

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

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

OpenAIRE

Schmidt, J E; Ahring, B K

1993-01-01

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

Biochemistry and physiology of anaerobic bacteria

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-05-18

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

Description of Clostridium phoceensis sp. nov., a new species within the genus Clostridium

Directory of Open Access Journals (Sweden)

M. Hosny

2016-11-01

Full Text Available Clostridium phoceensis sp. nov., strain GD3T (= CSUR P1929 = DSM 100334 is the type strain of C. phoceensis sp. nov., a new species within the genus Clostridium. This strain was isolated from the gut microbiota of a 28-year-old healthy French man. C. phoceensis is a Gram-negative, spore-forming, nonmotile, strictly anaerobic bacterium. We describe its complete genome sequence and annotation, together with its phenotypic characteristics.

Clostridium thiosulfatireducens sp. nov., a proteolytic, thiosulfate- and sulfur-reducing bacterium isolated from an upflow anaerobic sludge blanket (UASB) reactor.

Science.gov (United States)

Hernández-Eugenio, Guadalupe; Fardeau, Marie-Laure; Cayol, Jean-Luc; Patel, Bharat K C; Thomas, Pierre; Macarie, Hervé; Garcia, Jean-Louis; Ollivier, Bernard

2002-09-01

A strictly anaerobic, gram-positive, sporulating rod (0.5-0.6 x 2.0-4.0 microm), designated strain Lup 21T, was isolated from an upflow anaerobic sludge blanket (UASB) reactor treating cheese-factory wastewater. Strain Lup 21T was motile by means of peritrichous flagella, had a G+C content of 31.4 mol% and grew optimally at 37 degrees C, pH 7.4, in the absence of NaCl. It is a heterotrophic micro-organism, utilizing proteinaceous compounds (gelatin, peptides, Casamino acids and various single amino acids) but unable to use any of the carbohydrates tested as a carbon and energy source. It reduced thiosulfate and elemental sulfur to sulfide in the presence of Casamino acids as carbon and energy sources. Acetate, butyrate, isobutyrate, isovalerate, CO2 and sulfide were end products from oxidation of gelatin and Casamino acids in the presence of thiosulfate as an electron acceptor. In the absence of thiosulfate, serine, lysine, methionine and histidine were fermented. On the basis of 16S rRNA similarity, strain Lup 21T was related to members of the low-G+C Clostridiales group, Clostridium subterminale DSM 6970T being the closest relative (with a sequence similarity of 99.4%). DNA-DNA hybridization was 56% with this species. On the basis of phenotypic, genotypic and phylogenetic characteristics, the isolate was designated as a novel species of the genus Clostridium, Clostridium thiosulfatireducens sp. nov. The type strain is strain Lup 21T (= DSM 13105T = CIP 106908T).

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

Science.gov (United States)

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

2016-01-01

Animal manure comprises an important reservoir for antibiotic resistance genes (ARGs), but the variation in ARGs during anaerobic digestion at various temperatures and its underlying mechanism remain unclear. Thus, we performed anaerobic digestion using dairy manure at three temperature levels (moderate: 20 °C, mesophilic: 35 °C, and thermophilic: 55 °C), to analyze the dynamics of ARGs and bacterial communities by quantitative PCR and 16S rRNA gene sequencing. We found that 8/10 detected ARGs declined and 5/10 decreased more than 1.0 log during thermophilic digestion, whereas only four and five ARGs decreased during moderate and mesophilic digestion, respectively. The changes in ARGs and bacterial communities were similar under the moderate and mesophilic treatments, but distinct from those in the thermophilic system. Potential pathogens such as Bacteroidetes, Proteobacteria, and Corynebacterium were removed by thermophilic digestion but not by moderate and mesophilic digestion. The bacterial community succession was the dominant mechanism that influenced the variation in ARGs and integrons during anaerobic digestion. Thermophilic digestion decreased the amount of mesophilic bacteria (Bacteroidetes and Proteobacteria) carrying ARGs. Anaerobic digestion generally decreased the abundance of integrons by eliminating the aerobic hosts of integrons (Actinomycetales and Bacilli). Thermophilic anaerobic digestion is recommended for the treatment and reuse of animal manure. PMID:27444518

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

International Nuclear Information System (INIS)

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

2015-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-02-15

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

Hydrogenomics of the extremely thermophilic bacterium Caldicellulosiruptor saccharolyticus

NARCIS (Netherlands)

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

2008-01-01

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

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

OpenAIRE

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

1992-01-01

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

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

Science.gov (United States)

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

2014-01-15

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

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

Science.gov (United States)

Miroshnichenko, Margarita L; Bonch-Osmolovskaya, Elizaveta A

2006-04-01

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

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

DEFF Research Database (Denmark)

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

2008-01-01

was not detoxified, ethanol yield in a range of 0.39-0.42 g/g was obtained. Overall, sugar efficiency to ethanol was 68-76%. The reactor was operated continuously for approximately 143 days, and no contamination was seen without the use of any agent for preventing bacterial infections. The tested microorganism has......Thermophilic ethanol fermentation of wet-exploded wheat straw hydrolysate was investigated in a continuous immobilized reactor system. The experiments were carried out in a lab-scale fluidized bed reactor (FBR) at 70C. Undetoxified wheat straw hydrolysate was used (3-12% dry matter), corresponding...... to sugar mixtures of glucose and xylose ranging from 12 to 41 g/l. The organism, thermophilic anaerobic bacterium Thermoanaerobacter BG1L1, exhibited significant resistance to high levels of acetic acid (up to 10 g/l) and other metabolic inhibitors present in the hydrolysate. Although the hydrolysate...

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

International Nuclear Information System (INIS)

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

2014-01-01

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

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

Directory of Open Access Journals (Sweden)

Podkaminer Kara K

2012-06-01

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

A Thermophilic Phage Endolysin Fusion to a Clostridium perfringens-Specific Cell Wall Binding Domain Creates an Anti-Clostridium Antimicrobial with Improved Thermostability

Directory of Open Access Journals (Sweden)

Steven M. Swift

2015-06-01

Full Text Available Clostridium perfringens is the third leading cause of human foodborne bacterial disease and is the presumptive etiologic agent of necrotic enteritis among chickens. Treatment of poultry with antibiotics is becoming less acceptable. Endolysin enzymes are potential replacements for antibiotics. Many enzymes are added to animal feed during production and are subjected to high-heat stress during feed processing. To produce a thermostabile endolysin for treating poultry, an E. coli codon-optimized gene was synthesized that fused the N-acetylmuramoyl-L-alanine amidase domain from the endolysin of the thermophilic bacteriophage ɸGVE2 to the cell-wall binding domain (CWB from the endolysin of the C. perfringens-specific bacteriophage ɸCP26F. The resulting protein, PlyGVE2CpCWB, lysed C. perfringens in liquid and solid cultures. PlyGVE2CpCWB was most active at pH 8, had peak activity at 10 mM NaCl, 40% activity at 150 mM NaCl and was still 16% active at 600 mM NaCl. The protein was able to withstand temperatures up to 50° C and still lyse C. perfringens. Herein, we report the construction and characterization of a thermostable chimeric endolysin that could potentially be utilized as a feed additive to control the bacterium during poultry production.

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

NARCIS (Netherlands)

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

2002-01-01

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

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

African Journals Online (AJOL)

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

A simple and sensitive quality control method of the anaerobic atmosphere for identification and antimicrobial susceptibility testing of anaerobic bacteria

DEFF Research Database (Denmark)

Justesen, Tage; Justesen, Ulrik Stenz

2013-01-01

The maintenance of a strict anaerobic atmosphere is essential for the culture of strict anaerobic bacteria. We describe a simple and sensitive quality control method of the anaerobic atmosphere, based on the measurement of the zone diameter around a 5-μg metronidazole disk when testing...... an aerotolerant Clostridium perfringens strain. A zone diameter above 27 mm was indicative of acceptable anaerobic conditions....

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

OpenAIRE

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

2015-01-01

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

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

NARCIS (Netherlands)

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

2003-01-01

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

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

Science.gov (United States)

2010-03-01

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

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

Science.gov (United States)

Kuo, Wen-Chien; Cheng, Kae-Yiin

2007-07-01

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

Molecular genetic studies on obligate anaerobic bacteria

International Nuclear Information System (INIS)

Woods, D.R.

1982-01-01

Molecular genetic studies on obligate anaerobic bacteria have lagged behind similar studies in aerobes. However, the current interest in biotechnology, the involvement of anaerobes in disease and the emergence of antibioticresistant strains have focused attention on the genetics of anaerobes. This article reviews molecular genetic studies in Bacteroides spp., Clostridium spp. and methanogens. Certain genetic systems in some anaerobes differ from those in aerobes and illustrate the genetic diversity among bacteria

Studies on the enzymology of cellulose degradation by the anaerobic bacterium Clostridium thermocellum and the anaerobic fungus Neocallimastix frontalis

Energy Technology Data Exchange (ETDEWEB)

Bhat, K.M.; Gow, L.A.; Wilson, C.A.; Wood, T.W. (Rowett Research Inst., Aberdeen (UK))

1990-01-01

The extracellular cellulases from the anaerobic bacterium Clostridium thermocellum and the anaerobic rumen fungus Neocallimastix frontalis are very active on crystalline cellulose. In both cases the activity resides in a high molecular weight complex. The complex from C. thermocellum (termed the cellulosome) was found to be readily dissociated at pH 5.0 and at room temperature by a mixture of SDS, EDTA and DTT. Virtually all the activity of the unfractionated cellulosome was recovered when the dissociated enzyme components were reassociated by dialysis. Thus, the route is now established for the first time for a meaningful study of the mechanism of cellulase action of this commercially important enzyme system. Nearly all of the activity to crystalline cellulose shown by the cellulase of N. frontalis was associated with a fraction which comprised only 2% of the extracellular protein, 3% of the endoglucanase and 3% of the {beta}-glucosidase. This fraction, which could be isolated by affinity chromatography on cellulose, was produced in greater quantity when the fungus was grown in co-culture with the methanogen, Methanobrevibacter smithii. The specific activity of the partially purified enzyme for degradation of crystalline cellulose was several-fold greater than that produced by the aerobic fungus T. reesei, which is being developed world-wide for its commercial potential for converting cellulose to fermentable soluble sugars. The cellulase of N. frontalis clearly has great commercial potential. 39 refs., 19 figs., 22 tabs.

Anaerobic co-digestion of dairy manure and potato waste

Science.gov (United States)

Yadanaparthi, Sai Krishna Reddy

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

Postpartum Clostridium sordellii infection associated with fatal toxic shock syndrome

DEFF Research Database (Denmark)

Rørbye, C; Petersen, Ina Sleimann; Nilas, Lisbeth

2000-01-01

Clostridium bacteria are anaerobic Gram positive spore-form-ing bacilli, known to cause distinct clinical syndromes such as botulism, tetanus, pseudomembranous colitis and myonecrosis. The natural habitats of Clostridium species are soil, water and the gastrointestinal tract of animals and humans....... In 5-10% of all women, Clostridium species are also found to be normal inhabitants in the microbial flora of the female genital tract. In case of a non-sexually transmitted genital tract infection, Clostridium species are isolated in 4-20%, and clostridium welchii seems to be the most common isolate....... Clostridium sordellii is rarely encountered in clinical specimens (1% of Clostridium species), but it has been described as a human pathogen with fatal potential. Two toxins, a lethal and a hemorrhagic (that antigenically and pathophysiologically appear similar to Clostridium difficile toxins B and A...

Inhibitory effects on anaerobic digestion of swine manure

Energy Technology Data Exchange (ETDEWEB)

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

2002-06-15

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

Inhibitory effects on anaerobic digestion of swine manure

International Nuclear Information System (INIS)

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

2002-01-01

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

112 current trend in antimicrobial susceptibility pattern of clostridium ...

African Journals Online (AJOL)

DR. AMINU

inorganic substances. The odour usually gives a suggestion that Clostridium species was present. C. tetani is an obligate anaerobe, and therefore its isolation requires an environment, which is totally devoid of even a trace of oxygen. The technique applied in this research to create an anaerobic condition was found to be ...

Azoreductase activity of anaerobic bacteria isolated from human intestinal microflora.

Science.gov (United States)

Rafii, F; Franklin, W; Cerniglia, C E

1990-07-01

A plate assay was developed for the detection of anaerobic bacteria that produce azoreductases. With this plate assay, 10 strains of anaerobic bacteria capable of reducing azo dyes were isolated from human feces and identified as Eubacterium hadrum (2 strains), Eubacterium spp. (2 species), Clostridium clostridiiforme, a Butyrivibrio sp., a Bacteroides sp., Clostridium paraputrificum, Clostridium nexile, and a Clostridium sp. The average rate of reduction of Direct Blue 15 dye (a dimethoxybenzidine-based dye) in these strains ranged from 16 to 135 nmol of dye per min per mg of protein. The enzymes were inactivated by oxygen. In seven isolates, a flavin compound (riboflavin, flavin adenine dinucleotide, or flavin mononucleotide) was required for azoreductase activity. In the other three isolates and in Clostridium perfringens, no added flavin was required for activity. Nondenaturing polyacrylamide gel electrophoresis showed that each bacterium expressed only one azoreductase isozyme. At least three types of azoreductase enzyme were produced by the different isolates. All of the azoreductases were produced constitutively and released extracellularly.

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

DEFF Research Database (Denmark)

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

2011-01-01

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

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

Science.gov (United States)

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

2016-01-01

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

Potential for using thermophilic anaerobic bacteria for bioethanol production from hemicellulose

DEFF Research Database (Denmark)

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

2004-01-01

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

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

Science.gov (United States)

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

2013-10-01

An effective two-stage sewage sludge digestion process, consisting of thermophilic aerobic digestion (TAD) followed by mesophilic anaerobic digestion (MAD), was developed for efficient sludge reduction and methane production. Using TAD as a biological pretreatment, the total volatile suspended solid reduction (VSSR) and methane production rate (MPR) in the MAD reactor were significantly improved. According to denaturing gradient gel electrophoresis (DGGE) analysis, the results indicated that the dominant bacteria species such as Ureibacillus thermophiles and Bacterium thermus in TAD were major routes for enhancing soluble organic matter. TAD pretreatment using a relatively short SRT of 1 day showed highly increased soluble organic products and positively affected an increment of bacteria populations which performed interrelated microbial metabolisms with methanogenic species in the MAD; consequently, a quantitative real-time PCR indicated greatly increased Methanosarcinales (acetate-utilizing methanogens) in the MAD, resulting in enhanced methane production. Copyright © 2013 Elsevier Ltd. All rights reserved.

Advances in Consolidated Bioprocessing Using Clostridium thermocellum and Thermoanaerobacter saccharolyticum

Energy Technology Data Exchange (ETDEWEB)

Lynd, Lee R. [Dartmouth College, Thayer School of Engineering; Guss, Adam M. [ORNL; Himmel, Mike [National Renewable Energy Laboratory (NREL); Beri, Dhananjay [Dartmouth College, Thayer School of Engineering; Herring, Christopher [Mascoma Corporation; Holwerda, Evert [Dartmouth College, Thayer School of Engineering; Murphy, Sean J. [Dartmouth College, Thayer School of Engineering; Olson, Daniel G. [Dartmouth College, Thayer School of Engineering; Paye, Julie [Dartmouth College, Thayer School of Engineering; Rydzak, Thomas [ORNL; Shao, Xiongjun [Dartmouth College, Thayer School of Engineering; Tian, Liang [Dartmouth College, Thayer School of Engineering; Worthen, Robert [Dartmouth College, Thayer School of Engineering

2016-11-01

Recent advances are addressed pertaining to consolidated bioprocessing (CBP) of plant cell walls to ethanol using two thermophilic, saccharolytic bacteria: the cellulose-fermenting Clostridium thermocellum and the hemicellulose- fermenting ermoanaerobacterium saccharolyticum. On the basis of the largest comparative dataset assembled to date, it appears that C. thermocellum is substantially more effective at solubilizing unpretreated plant cell walls than industry-standard fungal cellulase, and that this is particularly the case for more recalcitrant feedstocks. e distinctive central metabolism of C. thermocellum appears to involve more extensive energy coupling (e.g., on the order of 5 ATP per glucosyl moiety) than most fermentative anaerobes. Ethanol yields and titers realized by engineered strains of T. saccharolyticum meet standards for industrial feasibility and provide an important proof of concept as well as a model that may be emulated in other organisms. Progress has also been made with C. thermocellum, although not yet to this extent. e current state of strain development is summarized and outstanding challenges for commercial application are discussed. We speculate that CBP organism development is more promising starting with naturally occurring cellulolytic microbes as compared to starting with noncellulolytic hosts.

New industrial butanol-producing organism, Clostridium amylovorum

Energy Technology Data Exchange (ETDEWEB)

Cataldi, M S

1964-01-01

A new Clostridium was isolated from starch-containing substances; it ferments corn and potato starch and sugar molasses, giving important yields of butanol and acetone; it is gram-positive, strictly anaerobic and sporulates in plectron form.

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

Science.gov (United States)

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

2017-12-01

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

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

Science.gov (United States)

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

2015-12-01

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

Colocalization and Disposition of Cellulosomes in Clostridium clariflavum as Revealed by Correlative Superresolution Imaging

Directory of Open Access Journals (Sweden)

Lior Artzi

2018-02-01

Full Text Available Cellulosomes are multienzyme complexes produced by anaerobic, cellulolytic bacteria for highly efficient breakdown of plant cell wall polysaccharides. Clostridium clariflavum is an anaerobic, thermophilic bacterium that produces the largest assembled cellulosome complex in nature to date, comprising three types of scaffoldins: a primary scaffoldin, ScaA; an adaptor scaffoldin, ScaB; and a cell surface anchoring scaffoldin, ScaC. This complex can contain 160 polysaccharide-degrading enzymes. In previous studies, we proposed potential types of cellulosome assemblies in C. clariflavum and demonstrated that these complexes are released into the extracellular medium. In the present study, we explored the disposition of the highly structured, four-tiered cell-anchored cellulosome complex of this bacterium. Four separate, integral cellulosome components were subjected to immunolabeling: ScaA, ScaB, ScaC, and the cellulosome’s most prominent enzyme, GH48. Imaging of the cells by correlating scanning electron microscopy and three-dimensional (3D superresolution fluorescence microscopy revealed that some of the protuberance-like structures on the cell surface represent cellulosomes and that the components are highly colocalized and organized by a defined hierarchy on the cell surface. The display of the cellulosome on the cell surface was found to differ between cells grown on soluble or insoluble substrates. Cell growth on microcrystalline cellulose and wheat straw exhibited dramatic enhancement in the amount of cellulosomes displayed on the bacterial cell surface.

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

Science.gov (United States)

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

2010-07-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2009-06-15

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

Azoreductase activity of anaerobic bacteria isolated from human intestinal microflora.

Science.gov (United States)

Rafii, F; Franklin, W; Cerniglia, C E

1990-01-01

A plate assay was developed for the detection of anaerobic bacteria that produce azoreductases. With this plate assay, 10 strains of anaerobic bacteria capable of reducing azo dyes were isolated from human feces and identified as Eubacterium hadrum (2 strains), Eubacterium spp. (2 species), Clostridium clostridiiforme, a Butyrivibrio sp., a Bacteroides sp., Clostridium paraputrificum, Clostridium nexile, and a Clostridium sp. The average rate of reduction of Direct Blue 15 dye (a dimethoxybenzidine-based dye) in these strains ranged from 16 to 135 nmol of dye per min per mg of protein. The enzymes were inactivated by oxygen. In seven isolates, a flavin compound (riboflavin, flavin adenine dinucleotide, or flavin mononucleotide) was required for azoreductase activity. In the other three isolates and in Clostridium perfringens, no added flavin was required for activity. Nondenaturing polyacrylamide gel electrophoresis showed that each bacterium expressed only one azoreductase isozyme. At least three types of azoreductase enzyme were produced by the different isolates. All of the azoreductases were produced constitutively and released extracellularly. Images PMID:2202258

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

NARCIS (Netherlands)

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

2003-01-01

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

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

KAUST Repository

Ghanimeh, Sophia A.

2012-08-01

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

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

KAUST Repository

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

2012-01-01

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

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

DEFF Research Database (Denmark)

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

2006-01-01

Three operational strategies to reduce inhibition due to ammonia during thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste (SS-OFMSW) rich in proteins were investigated. Feed was prepared by diluting SS-OFMSW (ratio of 1:4) with tap water or reactor process...... ammonium bicarbonate additions. Dilution of SS-OFMSW with fresh water showed a stable performance with volatile fatty acids of solids (VS). Use of recirculated process water after stripping ammonia showed even better performance with a methane yield...... of 0.43 m(3) kg(-1)VS. Recirculation of process water alone on the other hand, resulted in process inhibition at both TAN levels of 3.5 and 5.5 g-N l(-1). However, after a short period, the process recovered and adapted to the tested TAN levels. Thus, use of recirculated process water after stripping...

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

Science.gov (United States)

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

2006-01-01

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

Thermophilic subseafloor microorganisms from the 1996 North Gorda Ridge eruption

Science.gov (United States)

Summit, Melanie; Baross, John A.

1998-12-01

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

Anaerobic bacteria in wastewater treatment plant.

Science.gov (United States)

Cyprowski, Marcin; Stobnicka-Kupiec, Agata; Ławniczek-Wałczyk, Anna; Bakal-Kijek, Aleksandra; Gołofit-Szymczak, Małgorzata; Górny, Rafał L

2018-03-28

The objective of this study was to assess exposure to anaerobic bacteria released into air from sewage and sludge at workplaces from a wastewater treatment plant (WWTP). Samples of both sewage and sludge were collected at six sampling points and bioaerosol samples were additionally collected (with the use of a 6-stage Andersen impactor) at ten workplaces covering different stages of the technological process. Qualitative identification of all isolated strains was performed using the biochemical API 20A test. Additionally, the determination of Clostridium pathogens was carried out using 16S rRNA gene sequence analysis. The average concentration of anaerobic bacteria in the sewage samples was 5.49 × 10 4 CFU/mL (GSD = 85.4) and in sludge-1.42 × 10 6 CFU/g (GSD = 5.1). In turn, the average airborne bacterial concentration was at the level of 50 CFU/m 3 (GSD = 5.83) and the highest bacterial contamination (4.06 × 10 3  CFU/m 3 ) was found in winter at the bar screens. In total, 16 bacterial species were determined, from which the predominant strains belonged to Actinomyces, Bifidobacterium, Clostridium, Propionibacterium and Peptostreptococcus genera. The analysis revealed that mechanical treatment processes were responsible for a substantial emission of anaerobic bacteria into the air. In both the sewage and air samples, Clostridium perfringens pathogen was identified. Anaerobic bacteria were widely present both in the sewage and in the air at workplaces from the WWTP, especially when the technological process was performed in closed spaces. Anaerobic bacteria formed small aggregates with both wastewater droplets and dust particles of sewage sludge origin and as such may be responsible for adverse health outcomes in exposed workers.

Clostridium cadaveris bacteraemia: two cases and review.

NARCIS (Netherlands)

Schade, R.P.; Rijn, M. Van; Timmers, H.J.L.M.; Dofferhoff, A.S.M.; Klaassen, C.H.W.; Meis, J.F.G.M.

2006-01-01

Clostridium cadaveris is a strict anaerobic Gram-positive rod that is the most prominent bacterium during the decay of dead bodies. We present 2 rare cases of bacteraemia with C. cadaveris. The source of both infectious episodes was most probably of gastrointestinal origin.

Selected Topics in Anaerobic Bacteriology.

Science.gov (United States)

Church, Deirdre L

2016-08-01

Alteration in the host microbiome at skin and mucosal surfaces plays a role in the function of the immune system, and may predispose immunocompromised patients to infection. Because obligate anaerobes are the predominant type of bacteria present in humans at skin and mucosal surfaces, immunocompromised patients are at increased risk for serious invasive infection due to anaerobes. Laboratory approaches to the diagnosis of anaerobe infections that occur due to pyogenic, polymicrobial, or toxin-producing organisms are described. The clinical interpretation and limitations of anaerobe recovery from specimens, anaerobe-identification procedures, and antibiotic-susceptibility testing are outlined. Bacteriotherapy following analysis of disruption of the host microbiome has been effective for treatment of refractory or recurrent Clostridium difficile infection, and may become feasible for other conditions in the future.

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

International Nuclear Information System (INIS)

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

2016-01-01

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

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

Science.gov (United States)

Zhang, Tong; Yang, Ying; Pruden, Amy

2015-09-01

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

Starch-degrading enzymes from anaerobic non-clostridial bacteria

Energy Technology Data Exchange (ETDEWEB)

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

1990-08-01

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

Detection of Clostridium tyrobutyricum using cultivation and biochemical methods and polymerase chain reaction

Directory of Open Access Journals (Sweden)

Radka Burdychová

2007-01-01

Full Text Available Anaerobic spore-forming bacteria of the genus Clostridium are commonly present in raw milk and some milk products. Their spores can survive pasteurization and can provoke so called late blowing defect in cheese caused by butyric acid fermentation. The only species of the genus Clostridium that is able to provoke late blowing is Clostridium tyrobutyricum.In this work, two cultivation methods for detection of butyric acid producing clostridia in raw and pasteurized milk and in cheese samples were compared. The results show that tube method is suitable for route identification (in concentration 102 CFU/ml or /g of clostridia in milk and cheese. The standard cultivation technique is suitable for more sensitive identification (10 CFU/ml or /g. All presumptive colonies grown anaerobically on selective RCM agar with polymyxine B (500 μg/ml were classified to be of species Clostridium tyrobutyricum using PCR only. The confirmation using API tests were different in 50 % cases. The results show, that described PCR method is suitable for rapid screening of the presence of Clostridium tyrobutyricum in milk and cheese. PCR from one colony is possible to use for the analysis.

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

Science.gov (United States)

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

2013-05-01

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

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

International Nuclear Information System (INIS)

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

1993-01-01

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

Purification and crystallization of a trimodular complex comprising the type II cohesin–dockerin interaction from the cellulosome of Clostridium thermocellum

International Nuclear Information System (INIS)

Adams, Jarrett J.; Pal, Gour; Yam, Katherine; Spencer, Holly L.; Jia, Zongchao; Smith, Steven P.

2004-01-01

A trimodular complex comprising the type II cohesin–dockerin interaction from the cellulosome of C. thermocellum has been purified and crystallized by the hanging-drop vapour-diffusion method. A native crystal and a selenomethionine derivative have been analyzed using X-ray diffraction. The high-affinity calcium-mediated type II cohesin–dockerin interaction is responsible for the attachment of the multi-enzyme cellulose-degrading complex, termed the cellulosome, to the cell surface of the thermophilic anaerobe Clostridium thermocellum. A trimodular 40 kDa complex comprising the SdbA type II cohesin and the the CipA type II dockerin–X module modular pair from the cellulosome of C. thermocellum has been crystallized. The crystals belong to space group P2 1 2 1 2 1 , with unit-cell parameters a = 45.21, b = 52.34, c = 154.69 Å. The asymmetric unit contains one molecule of the protein complex and native and selenomethionine-derivative crystals diffracted to 2.1 and 2.0 Å, respectively

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

Science.gov (United States)

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

2007-08-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2011-01-01

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

Conversion of Corn Stover Hydrolysates to Acids: Comparison Between Clostridium carboxidivorans P7 and Microbial Communities Developed from Lake Sediment and an Anaerobic Digester

Energy Technology Data Exchange (ETDEWEB)

Chen, Xiaowen [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Tucker, Melvin P [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Xia, Chunjie [Southern Illinois University; Kumar, Aditi [Carbondale Community High School; Liang, Yanna [Southern Illinois University

2017-01-18

Anaerobic fermentation is an environmentally sustainable technology for converting a variety of feedstocks to biofuels and bioproducts. Considering the complex nature of lignocellulosic hydrolysates, we aimed to investigate product formation from corn stover hydrolysates by using microbial communities under anaerobic conditions. A community developed from lake sediment was able to produce lactic acid from only glucose in the raw or overlimed hydrolysates. Another community from an anaerobic digester, however, was capable of using all hexose and pentose sugars in the raw and undetoxified hydrolysates and released lactic acid at 26.76 g/L. A pure acetogen, Clostridium carboxidivorans P7, was able to grow on the raw and overlimed hydrolysates, too. But the consumption of sugars was minimal and the total released acid concentrations were less than 2 g/L. Next generation sequencing of the enriched community derived from the anaerobic digester revealed the presence of Lactobacillus strains. The predominant species were Lactobacillus parafarraginis (72.6%) and L. buchneri (13.4%). Product titer from using this enriched community can be further enhanced by cultivating at fed-batch or continuous fermentation modes. Results from this study widened the door for producing valuable products from lignocellulosic feedstocks through using mixed cultures.

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

International Nuclear Information System (INIS)

Rivard, C.J.

1983-01-01

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

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

Science.gov (United States)

Schaefer, Scott H; Sung, Shihwu

2008-02-01

Anaerobic digestion of corn ethanol thin stillage was tested at thermophilic temperature (55 degrees C) with two completely stirred tank reactors. The thin stillage wastestream was organically concentrated with 100 g/L total chemical oxygen demand and 60 g/L volatiles solids and a low pH of approximately 4.0. Steady-state was achieved at 30-, 20-, and 15-day hydraulic retention times (HRTs) and digester failure at a 12-day HRT. Significant reduction of volatile solids was achieved, with a maximum reduction (89.8%) at the 20-day HRT. Methane yield ranged from 0.6 to 0.7 L methane/g volatile solids removed during steady-state operation. Effluent volatile fatty acids below 200 mg/L as acetic acid were achieved at 20- and 30-day HRTs. Ultrasonic pretreatment was used for one digester, although no significant improvement was observed. Ethanol plant natural gas consumption could be reduced 43 to 59% with the methane produced, while saving an estimated $7 to $17 million ($10 million likely) for a facility producing 360 million L ethanol/y.

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

DEFF Research Database (Denmark)

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

2005-01-01

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

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

DEFF Research Database (Denmark)

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

2010-01-01

Biomass samples taken during the continuous operation of thermophilic anaerobic digestors fed with manure and exposed to successive inhibitory pulses of long-chain fatty acids (LCFA) were characterized in terms of specific metabolic activities and 16S rDNA DGGE profiling of the microbial community....... Population profiles of eubacterial and archaeal 16S rDNA genes revealed that no significant shift on microbial community composition took place upon biomass exposure to LCFA. DNA sequencing of predominant DGGE bands showed close phylogenetic affinity to ribotypes characteristic from specific beta...... kinetics considering the relation between LCFA inhibitory substrate concentration and specific biomass content, as an approximation to the adsorption process, improved the model fitting and provided a better insight on the physical nature of the LCFA inhibition process. (C) 2009 Elsevier Ltd. All rights...

Anaerobic fermentation of beef cattle manure. Final report

Energy Technology Data Exchange (ETDEWEB)

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

1981-01-01

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

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

International Nuclear Information System (INIS)

2004-01-01

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

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

OpenAIRE

Ahring, Birgitte K.; Westermann, Peter

1987-01-01

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

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

DEFF Research Database (Denmark)

Zhu, Xinyu; Kougias, Panagiotis; Treu, Laura

2017-01-01

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

Microbial examination of anaerobic sludge adaptation to animal slurry.

Science.gov (United States)

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

2014-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1984-01-01

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

Anaerobic microplate assay for direct microbial conversion of switchgrass and Avicel using Clostridium thermocellum

Energy Technology Data Exchange (ETDEWEB)

Oguntimein, Gbekeloluwa B. [Morgan State Univ., Baltimore, MD (United States); Rodriguez, Jr., Miguel [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); National Lab., Oak Ridge, TN (United States). BioEnergy Science Center; Dumitrache, Alexandru [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); National Lab., Oak Ridge, TN (United States). BioEnergy Science Center; Shollenberger, Todd [National Renewable Energy Lab. (NREL), Golden, CO (United States); Decker, Stephen R. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Davison, Brian H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); National Lab., Oak Ridge, TN (United States). BioEnergy Science Center; Brown, Steven D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); National Lab., Oak Ridge, TN (United States). BioEnergy Science Center; LanzaTech, Inc., Skokie, IL (United States)

2017-11-09

Here, to develop and prototype a high-throughput microplate assay to assess anaerobic microorganisms and lignocellulosic biomasses in a rapid, cost-effective screen for consolidated bioprocessing potential. Clostridium thermocellum parent Δhpt strain deconstructed Avicel to cellobiose, glucose, and generated lactic acid, formic acid, acetic acid and ethanol as fermentation products in titers and ratios similar to larger scale fermentations confirming the suitability of a plate-based method for C. thermocellum growth studies. C. thermocellum strain LL1210, with gene deletions in the key central metabolic pathways, produced higher ethanol titers in the Consolidated Bioprocessing (CBP) plate assay for both Avicel and switchgrass fermentations when compared to the Δhpt strain. A prototype microplate assay system is developed that will facilitate high-throughput bioprospecting for new lignocellulosic biomass types, genetic variants and new microbial strains for bioethanol production.

Sensitive and selective culture medium for detection of environmental Clostridium difficile isolates without requirement for anaerobic culture conditions.

Science.gov (United States)

Cadnum, Jennifer L; Hurless, Kelly N; Deshpande, Abhishek; Nerandzic, Michelle M; Kundrapu, Sirisha; Donskey, Curtis J

2014-09-01

Effective and easy-to-use methods for detecting Clostridium difficile spore contamination would be useful for identifying environmental reservoirs and monitoring the effectiveness of room disinfection. Culture-based detection methods are sensitive for detecting C. difficile, but their utility is limited due to the requirement of anaerobic culture conditions and microbiological expertise. We developed a low-cost selective broth medium containing thioglycolic acid and l-cystine, termed C. difficile brucella broth with thioglycolic acid and l-cystine (CDBB-TC), for the detection of C. difficile from environmental specimens under aerobic culture conditions. The sensitivity and specificity of CDBB-TC (under aerobic culture conditions) were compared to those of CDBB (under anaerobic culture conditions) for the recovery of C. difficile from swabs collected from hospital room surfaces. CDBB-TC was significantly more sensitive than CDBB for recovering environmental C. difficile (36/41 [88%] versus 21/41 [51%], respectively; P = 0.006). C. difficile latex agglutination, an enzyme immunoassay for toxins A and B or glutamate dehydrogenase, and a PCR for toxin B genes were all effective as confirmatory tests. For 477 total environmental cultures, the specificity of CDBB-TC versus that of CDBB based upon false-positive yellow-color development of the medium without recovery of C. difficile was 100% (0 false-positive results) versus 96% (18 false-positive results), respectively. False-positive cultures for CDBB were attributable to the growth of anaerobic non-C. difficile organisms that did not grow in CDBB-TC. Our results suggest that CDBB-TC provides a sensitive and selective medium for the recovery of C. difficile organisms from environmental samples, without the need for anaerobic culture conditions. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

[Current clinical significance of anaerobic bacteremia].

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Jirsa, Roman; Marešová, Veronika; Brož, Zdeněk

2010-10-01

to estimate tje current clinical significance of anaerobic bacteremia in a group of Czech hospitals. this retrospective analysis comprised 8 444 anaerobic blood cultures in patients admitted to four Czech hospitals between 2004 and 2007. in 16 patients, blood cultures yielded significant anaerobic bacteria. Thus, anaerobic bacteremia accounted for less than 2 % of clinically significant bacteremia. Four patients (18 %) died but none of the deaths could be clearly attributable to anaerobic bacteria in the bloodstream. The most common comorbidities predisposing to anaerobic bacteremia and the most frequent sources of infection were similar to those reported by other authors. The majority of anaerobic bacteremia cases were due to gram-negative bacteria, followed by Clostridium perfringens and, surprisingly, Eubacterium spp. (particularly Eubacterium lentum). anaerobic bacteremia remains rare. The comparison of our data with those by other authors suggests that (despite the reported high mortality) the actual clinical significance of anaerobic bacteremia is rather controversial and that the anaerobic bacteremia might not correspond to more serious pathogenic role of the anaerobic bacteria as the source of infection.

Draft Genome Sequence of Antimicrobial-Producing Clostridium sp. JC272, Isolated from Marine Sediment

OpenAIRE

Tushar, L.; Sasi Jyothsna, T. S.; Sasikala, C.; Ramana, C. V.

2015-01-01

We announce the draft genome sequence of Clostridium sp. JC272, isolated from a sediment sample collected from marine habitats of Gujarat, India. Clostridium sp. JC272 is an obligate anaerobe and has the ability to produce antimicrobial compounds. The genome sequence indicates the strain?s capability of producing small peptides (microcins), which are potential novel antibiotics.

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

Science.gov (United States)

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

2018-06-15

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

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

Science.gov (United States)

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

2015-10-01

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

Probiotic containing Lactobacillus casei, Lactobacillus bulgaricus, and Streptococcus thermophiles (ACTIMEL) for the prevention of Clostridium difficile associated diarrhoea in the elderly with proximal femur fractures.

Science.gov (United States)

Mallina, Ravi; Craik, J; Briffa, N; Ahluwalia, Viren; Clarke, J; Cobb, A G

The incidence of Clostridium difficile associated diarrhoea (CDAD) is greater in elderly patients. Probiotics may have a beneficial effect in the prevention of CDAD. However, their effect in elderly orthopaedic patients has not been previously reported. Between April 2013 and April 2014, 105 patients admitted with femoral neck fractures, and who required 3days of antibiotics for infection of any cause, were prescribed the probiotic ACTIMEL until 3days after the last antibiotic dose. The incidence of CDAD was compared with historical controls (April 2011￢ﾀﾓApril 2012). There was no significant reduction in the incidence of CDAD in patients receiving probiotics (OR: 0.9; 95% CI 0.27￢ﾀﾓ2.91; p=0.8) and therefore we cannot recommend the use of ACTIMEL containing Lactobacillus casei, Lactobacillus bulgaricus, and Streptococcus thermophiles for this purpose in this patient group. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

2001-07-01

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

Antimicrobial susceptibility of anaerobic bacteria in New Zealand: 1999-2003.

Science.gov (United States)

Roberts, Sally A; Shore, Keith P; Paviour, Susan D; Holland, David; Morris, Arthur J

2006-05-01

Routine susceptibility testing of all anaerobic organisms is not advocated, but it is useful for laboratories to test periodically for anaerobic organisms and provide local susceptibility data to guide therapy. This study reports the national trend of antibiotic susceptibility of clinically significant anaerobes in New Zealand. Clinical isolates were tested using standardized methods against a range of antibiotics commonly used to treat anaerobic infections. Susceptibility was determined using NCCLS criteria. The change in susceptibility trends between this study and earlier studies was measured by comparing the geometric mean of the MIC. A total of 364 anaerobes were tested. Penicillin had poor activity against Bacteroides spp., Prevotella spp., Eubacterium spp., Clostridium tertium and Veillonella spp. In general, Fusobacterium spp., Bacteroides ureolyticus, Propionibacterium spp., Clostridium perfringens and anaerobic streptococci isolates, with the exception of Peptostreptococcus anaerobius, were penicillin susceptible. Amoxicillin/clavulanate showed good activity against most anaerobes, but resistance was seen with Bacteroides fragilis group and P. anaerobius isolates. Cefoxitin was more active than cefotetan, particularly against non-B. fragilis species, Eubacterium spp. and P. anaerobius. Meropenem and imipenem showed good activity against all anaerobes, with only 2 and 4% of Bacteroides spp., respectively, showing resistance. With the exception of Propionibacterium acnes isolates, which are predictably resistant, metronidazole was active against all anaerobes tested. There has been little change in susceptibility since 1997. Metronidazole, cefoxitin, piperacillin/tazobactam and amoxicillin/clavulanate remain good empirical choices when anaerobes are expected in our setting. No clinically relevant changes in susceptibility over time were found.

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

Science.gov (United States)

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

2018-02-01

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

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

DEFF Research Database (Denmark)

Luo, Gang; Angelidaki, Irini

2012-01-01

Biogas produced by anaerobic digestion, is mainly used in a gas motor for heat and electricity production. However, after removal of CO2, biogas can be upgraded to natural gas quality, giving more utilization possibilities, such as utilization as autogas, or distant utilization by using...... the existing natural gas grid. The current study presents a new biological method for biogas upgrading in a separate biogas reactor, containing enriched hydrogenotrophic methanogens and fed with biogas and hydrogen. Both mesophilic- and thermophilic anaerobic cultures were enriched to convert CO2 to CH4...... by addition of H2. Enrichment at thermophilic temperature (55°C) resulted in CO2 and H2 bioconversion rate of 320 mL CH4/(gVSS h), which was more than 60% higher than that under mesophilic temperature (37°C). Different dominant species were found at mesophilic- and thermophilic-enriched cultures, as revealed...

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

DEFF Research Database (Denmark)

Hubert, Casey; Arnosti, Carol; Brüchert, Volker

2010-01-01

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

Microbiology and management of joint and bone infections due to anaerobic bacteria.

Science.gov (United States)

Brook, Itzhak

2008-03-01

To describes the microbiology, diagnosis, and management of septic arthritis and osteomyelitis due to anaerobic bacteria. The predominant anaerobes in arthritis are anaerobic Gram-negative bacilli (AGNB) including the Bacteroides fragilis group, Fusobacterium spp., Peptostreptococcus spp., and Propionibacterium acnes. Infection with P. acnes is associated with a prosthetic joint, previous surgery, and trauma. B. fragilis group is associated with distant infection, Clostridium spp. with trauma, and Fusobacterium spp. with oropharyngeal infection. Most cases of anaerobic arthritis, in contrast to anaerobic osteomyelitis, involved a single isolate, and most cases are secondary to hematogenous spread. The predominant anaerobes in osteomyelitis are Bacteroides, Peptostreptococcus, Fusobacterium, and Clostridium spp. as well as P. acnes. Conditions predisposing to bone infections are vascular disease, bites, contiguous infection, peripheral neuropathy, hematogenous spread, and trauma. Pigmented Prevotella and Porphyromonas spp. are mostly isolated in skull and bite infections, members of the B. fragilis group in hand and feet infections, and Fusobacterium spp. in skull, bite, and hematogenous long bone infections. Many patients with osteomyelitis due to anaerobic bacteria have evidence of an anaerobic infection elsewhere in the body that is the source of the organisms involved in the osteomyelitis. Treatment of arthritis and osteomyelitis involving anaerobic bacteria includes symptomatic therapy, immobilization in some cases, adequate drainage of purulent material, and antibiotic therapy effective against these organisms. Anaerobic bacteria can cause septic arthritis and osteomyelitis. Correct diagnosis and appropriate therapy are important contributor to successful outcome.

Uterine Sarcoma Presenting with Sepsis from Clostridium perfringens Endometritis in a Postmenopausal Woman

Directory of Open Access Journals (Sweden)

Mary J. Kao

2018-01-01

Full Text Available Clostridium perfringens is an anaerobic gram positive rod that is found in normal vaginal and cervical flora in 1–10% of healthy women. Uterine infection with Clostridium perfringens is seen rarely but is often related to underlying uterine pathology and can progress quickly to sepsis. Early recognition of sepsis, prompt treatment with antibiotics, and source control with surgical management allow for optimal chance of recovery. We present a case of a postmenopausal woman who presented with sepsis, vaginal bleeding, and back pain who was found to have Clostridium perfringens infection in the setting of undifferentiated uterine sarcoma.

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

International Nuclear Information System (INIS)

Watanabe, L.; Arni, R.K.

1996-01-01

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

The isolation and characterization of new C. thermocellum strains and the evaluation of multiple anaerobic digestion systems

Science.gov (United States)

Lv, Wen

The overall objective of my research was to improve the efficiencies of bioconversions that produce renewable energy from lignocellulosic biomass. To this end, my studies addressed issues important to two promising strategies: consolidated bioprocessing (CBP) and anaerobic digestion (AD). CBP achieves saccharolytic enzyme production, hydrolysis, and fermentation in a single step and is considered to be the most cost-effective model. Anaerobic bacteria that can be used in CBP are highly desirable. To that end, two thermophilic and cellulolytic bacterial strains were isolated and characterized (Chapter 3). Based on 16S rRNA gene sequence analysis, both strains CS7 and CS8 are closely related to Clostridium thermocellum ATCC 27405. However, they had significantly higher specific cellulase activities and ethanol/acetate ratios than C. thermocellum ATCC 27405. As a result, CS7 and CS8 are two new highly cellulolytic and ethanologenic C. thermocellum strains, with application potentials in research and development of CBP. As some of the most promising AD processes, two temperature-phased AD (TPAD) systems, in comparison with a thermophilic single-stage AD (TSAD) system and a mesophilic two-stage AD (MTAD) system, were studied in treating high-strength dairy cattle manure. The TPAD systems, with the thermophilic digesters acidified (AT-TPAD, Chapter 4) or operated at neutral pH (NT-TPAD, Chapter 5), were optimized at the thermophilic temperature of 50°C and a volume ratio between the thermophilic and the mesophilic digesters of 1:2. Despite similar methane productions, the NT-TPAD system achieved significantly higher volatile solid (VS) removal than the AT-TPAD system and needed no external pH adjustments (Chapter 6). At the same overall OLR, the TSAD system achieved the highest performance, followed by the NT-TPAD and the MTAD systems (Chapter 7). Each digester harbored distinct yet dynamic microbial populations, some of which were significantly correlated or associated

In vitro activity of DMG-Mino and DMG-DM Dot, two new glycylcyclines, against anaerobic bacteria.

Science.gov (United States)

Nord, C E; Lindmark, A; Persson, I

1993-10-01

The in vitro activity of DMG-Mino and DMG-DM Dot against 350 anaerobic bacterial strains including anaerobic cocci, Propionibacterium acnes, Clostridium perfringens, Clostridium difficile, Bacteroides fragilis, other Bacteroides species and fusobacteria was determined by the agar dilution method. Their activity was compared with that of minocycline, doxycycline, piperacillin, cefoxitin, imipenem, clindamycin and metronidazole. DMG-Mino and DMG-DM Dot and imipenem were the most active agents tested. DMG-Mino and DMG-DM Dot had in vitro activity superior to that of minocycline and doxycycline.

The Purine-Utilizing Bacterium Clostridium acidurici 9a: A Genome-Guided Metabolic Reconsideration

OpenAIRE

Hartwich, Katrin; Poehlein, Anja; Daniel, Rolf

2012-01-01

Clostridium acidurici is an anaerobic, homoacetogenic bacterium, which is able to use purines such as uric acid as sole carbon, nitrogen, and energy source. Together with the two other known purinolytic clostridia C. cylindrosporum and C. purinilyticum, C. acidurici serves as a model organism for investigation of purine fermentation. Here, we present the first complete sequence and analysis of a genome derived from a purinolytic Clostridium. The genome of C. acidurici 9a consists ...

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

NARCIS (Netherlands)

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

2017-01-01

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

Phosphorylation of proteins in Clostridium thermohydrosulfuricum

International Nuclear Information System (INIS)

Londesborough, J.

1986-01-01

Cell extracts of the thermophile Clostridium thermohydrosulfuricum catalyzed the phosphorylation by (γ- 32 P)ATP of several endogenous proteins with M/sub r/s between 13,000 and 100,000. Serine and tyrosine were the main acceptors. Distinct substrate proteins were found in the soluble (e.g., proteins p66, p63, and p53 of M/sub r/s 66,000, 63,000, and 53,000, respectively) and particulate (p76 and p30) fractions, both of which contained protein kinase and phosphatase activity. The soluble fraction suppressed the phosphorylation of particulate proteins and contained a protein kinase inhibitor. Phosphorylation of p53 was promoted by 10μM fructose 1,6-bisphosphate or glucose 1,6-bisphosphate and suppressed by hexose monophosphates, whereas p30 and p13 were suppressed by 5 μM brain (but not spinach) calmodulin. Polyamines, including the odd polyamines characteristic of thermophiles, modulated the labeling of most of the phosphoproteins. Apart from p66, all the proteins labeled in vitro were also rapidly labeled in intact cells by 32 P/sub i/. Several proteins strongly labeled in vivo were labeled slowly or not at all in vitro

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

Science.gov (United States)

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

2015-01-01

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

TREATMENT OF CLOSTRIDIUM DIFFICILE- ASSOCIATED DISEASE

Directory of Open Access Journals (Sweden)

Snezana Antic-Mladenovic

2007-04-01

Full Text Available Clostridium difficile is a Gram-positive, spore-forming, anaerobic bacillus that is widely distributed in the environment, but is found as a part of a normal large bowel flora in approximately 3% of normal adults. C. difficile produces two protein exotoxins: toxin A and toxin B. Both toxins are responsible for causing the sings and symptoms of disease.C. difficile is now thought to be responsible for a spectrum of diseases, ranging from asymptomatic colonization to diarrhea of varying severity, life-threatening colitis, often as a consequence of long-term antibiotic exposure. This spectrum has become known as C. difficile-associated disease (CDAD.Treatment of Clostridium difficile-associated disease demand administration of effi-cient antibiotics (vancomycin, metronidazole, anion exchange resins and probiotics (Lactobacillus spp., Saccharomyces boulardii.

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

Science.gov (United States)

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

2014-01-01

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

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

KAUST Repository

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

2016-01-01

Results showed that thin stillage contains easily degradable compounds suitable for anaerobic digestion and that hybrid reactors can efficiently convert thin stillage to methane under mesophilic and thermophilic conditions. Furthermore, we found that optimal conditions for biological treatment of thin stillage were similar for both mesophilic and thermophilic reactors. Bar-coded pyrosequencing of the 16S rRNA gene identified different microbial communities in mesophilic and thermophilic reactors and these differences in the microbial communities could be linked to the composition of the thin stillage.

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

Energy Technology Data Exchange (ETDEWEB)

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

2009-09-15

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

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

DEFF Research Database (Denmark)

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

2015-01-01

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

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

International Nuclear Information System (INIS)

Mabala, Jojo Charlie

2012-01-01

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

Clostridium perfringens bacteremia caused by choledocholithiasis in the absence of gallbladder stones.

Science.gov (United States)

Atia, Antwan; Raiyani, Tejas; Patel, Pranav; Patton, Robert; Young, Mark

2012-10-21

A 67-years-old male presented with periumbilical abdominal pain, fever and jaundice. His anaerobic blood culture was positive for clostridium perfringens. Computed tomogram scan of the abdomen and abdominal ultrasound showed normal gallbladder and common bile duct (CBD). Subsequently magnetic resonance cholangiopancreaticogram showed choledocholithiasis. Endoscopic retrograde cholangiopancreaticogramwith sphincterotomy and CBD stone extraction was performed. The patient progressively improved with antibiotic therapy Choledocholithiasis should be considered as a source of clostridium perfringens bacteremia especially in the setting of elevated liver enzymes with cholestatic pattern.

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

Science.gov (United States)

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

2013-03-15

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

First Insights into the Genome Sequence of Clostridium thermopalmarium DSM 5974, a Butyrate-Producing Bacterium Isolated from Palm Wine.

Science.gov (United States)

Poehlein, Anja; Hettwer, Eva; Mohnike, Lennart; Daniel, Rolf

2018-04-26

Clostridium thermopalmarium is a moderate thermophilic, rod-shaped, and endospore-forming bacterium, which was isolated from palm wine in Senegal. Butyrate is produced from a broad variety of sugar substrates. Here, we present the draft genome sequence of C. thermopalmarium DSM 5974 (2.822 Mb) containing 2,665 predicted protein-encoding genes. Copyright © 2018 Poehlein et al.

Uterine Clostridium perfringens infection related to gynecologic malignancy.

Science.gov (United States)

Kremer, Kevin M; McDonald, Megan E; Goodheart, Michael J

2017-11-01

Uterine gas gangrene caused by Clostridium perfringens is a serious, often life-threatening infection that is rarely encountered in the practice of gynecologic oncology. However, the hypoxic nature of gynecologic cancers due to necrosis and/or prior radiation therapy creates a microenvironment optimal for proliferation of anaerobic bacteria such as the Clostridium species. Early recognition and aggressive treatment with IV antibiotics and surgical debridement remain the cornerstones of management in order to decrease morbidity and mortality. Here we present the case of a 52 year-old woman with a remote history of cervical cancer who was previously treated at our institution with primary chemotherapy and radiation and was then admitted decades later with Clostridium perfringens bacteremia and CT evidence of intrauterine abscess. The patient received a prolonged course of IV antibiotic therapy and subsequently underwent definitive surgical management with a total abdominal hysterectomy, bilateral salpingo-oophorectomy, small bowel resection with anastomosis for a utero-ileal fistula identified intraoperatively. Pathology from the uterine specimen demonstrated a primary poorly differentiated uterine adenocarcinoma. The patient recovered fully from her Clostridium perfringens infection and was discharged from the hospital shortly after surgical intervention.

Fulminant leukemoid reaction due to postpartum Clostridium sordellii infection

Directory of Open Access Journals (Sweden)

Prabhat Agrawal

2012-01-01

Full Text Available Clostridium sordellii is gram positive anaerobic spore forming rod and it has been demonstrated to cause gas gangrene, refractory shock, leukemoid reaction, and pleuroperitoneal effusion due to capillary leak. We report here a case of postpartum female who presented with leukemoid reaction, ascites, pleural effusion, and shock without fever 7 days after normal vaginal home delivery.

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

Science.gov (United States)

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

2015-06-01

This study was conducted to investigate the effects of sulfate on propionate degradation and higher organic loading rate (OLR) achievement in a thermophilic AnMBR for 373days using coffee grounds, milk and waste activated sludge (WAS) as the co-substrate. Without the addition of sulfate, the anaerobic system failed at an OLR of 14.6g-COD/L/d, with propionate accumulating to above 2.23g-COD/L, and recovery by an alkalinity supplement was not successful. After sulfate was added into substrates at a COD/SO4(2-) ratio of 200:1 to 350:1, biogas production increased proportionally with OLR increasing from 4.06 to 15.2g-COD/L/d. Propionic acid was maintained at less than 100mg-COD/L due to the effective conversion of propionic acid to methane after the sulfate supplement was added. The long-term stable performance of the AnMBR indicated that adding sulfate was beneficial for the degradation of propionate and achieving a higher OLR under the thermophilic condition. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

2013-11-01

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

The fate of methanol in thermophilic-anaerobic environments

NARCIS (Netherlands)

Paulo, P.L.

2002-01-01

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

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

DEFF Research Database (Denmark)

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

2006-01-01

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

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

Science.gov (United States)

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

2005-01-01

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

In vitro activity of flomoxef compared to moxalactam, cefoxitin, cefotaxime, and clindamycin against anaerobes.

Science.gov (United States)

Werner, H; Heizmann, W; Luft, G

1988-11-01

To assess the in vitro activity of flomoxef (6315-S), moxalactam, cefoxitin, cefotaxime, and clindamycin against anaerobes 197 clinical isolates (27 Bacteroides fragilis, 42 B. thetaiotaomicron, 10 B. vulgatus, 7 B. ovatus, 6 B. uniformis, 6 B. distasonis, 7 Bacteroides melaninogenicus group, 11 Bacteroides oralis group, 21 Clostridium difficile, 7 C. perfringens, 3 C. sporogenes, 3 Clostridium spp., 33 Propionibacterium acnes, 14 Peptococcaceae) were studied by means of agar dilution tests. The MIC90 of B. fragilis was less than 2 micrograms/ml for flomoxef, less than 4 micrograms/ml for moxalactam, less than 16 micrograms/ml for cefoxitin, less than 128 micrograms/ml for cefotaxime and less than 2 micrograms/ml for clindamycin. The respective MIC90's of B. thetaiotaomicron were less than 64, less than 128, less than 32, less than 256 and 8 micrograms/ml. Strains of the other Bacteroides species and groups were more susceptible to flomoxef and the other antibiotics than B. thetaiotaomicron. Against Clostridium difficile flomoxef (MIC90 less than 4 micrograms/ml) proved to be superior to the other agents tested. Most of the Clostridium strains other than C. difficile were also susceptible to flomoxef; anaerobic grampositive cocci and Propionibacterium acnes were very sensitive (MIC90's less than 1 and less than or equal to 0.125 micrograms/ml, respectively). Its anti-anaerobic activity, together with its efficacy against aerobes, should make flomoxef a useful adjunct to the arsenal of modern antibiotic therapy.

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

International Nuclear Information System (INIS)

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

2015-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2015-09-15

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

An active principle of Nigella sativa L., thymoquinone, showing significant antimicrobial activity against anaerobic bacteria.

Science.gov (United States)

Randhawa, Mohammad Akram; Alenazy, Awwad Khalaf; Alrowaili, Majed Gorayan; Basha, Jamith

2017-01-01

Thymoquinone (TQ) is the major active principle of Nigella sativa seed (black seed) and is known to control many fungi, bacteria, and some viruses. However, the activity of TQ against anaerobic bacteria is not well demonstrated. Anaerobic bacteria can cause severe infections, including diarrhea, aspiration pneumonia, and brain abscess, particularly in immunodeficient individuals. The present study aimed to investigate the in vitro antimicrobial activity of TQ against some anaerobic pathogens in comparison to metronidazole. Standard, ATCC, strains of four anaerobic bacteria ( Clostridium difficile , Clostridium perfringens , Bacteroides fragilis , and Bacteroides thetaiotaomicron ), were initially isolated on special Brucella agar base (with hemin and vitamin K). Then, minimum inhibitory concentrations (MICs) of TQ and metronidazole were determined against these anaerobes when grown in Brucella agar, using serial agar dilution method according to the recommended guidelines for anaerobic organisms instructed by the Clinical and Laboratory Standards Institute. TQ showed a significant antimicrobial activity against anaerobic bacteria although much weaker than metronidazole. MICs of TQ and metronidazole against various anaerobic human pathogens tested were found to be between 10-160 mg/L and 0.19-6.25 mg/L, respectively. TQ controlled the anaerobic human pathogenic bacteria, which supports the use of N. sativa in the treatment of diarrhea in folk medicine. Further investigations are in need for determination of the synergistic effect of TQ in combination with metronidazole and the activity of derivatives of TQ against anaerobic infections.

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

Science.gov (United States)

Osipiuk, J; Joachimiak, A

1997-09-12

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

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

KAUST Repository

Ghanimeh, Sophia A.

2013-11-01

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

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

Science.gov (United States)

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

2013-11-01

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

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

Science.gov (United States)

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

2012-01-01

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

Bioaugmentation with an acetate-oxidising consortium as a tool to tackle ammonia inhibition of anaerobic digestion

DEFF Research Database (Denmark)

Fotidis, Ioannis; Karakashev, Dimitar Borisov; Angelidaki, Irini

2013-01-01

Ammonia is the major inhibitor of anaerobic digestion (AD) process in biogas plants. In the current study, the bioaugmentation of the ammonia tolerant SAO co-culture (i.e. Clostridium ultunense spp. nov. in association with Methanoculleus spp. strain MAB1) in a mesophilic up-flow anaerobic sludge...

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

Directory of Open Access Journals (Sweden)

Kimberly M. Webb

2012-01-01

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

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

Science.gov (United States)

Webb, Kimberly M; DiRuggiero, Jocelyne

2012-01-01

Radiation-resistant bacteria have garnered a great deal of attention from scientists seeking to expose the mechanisms underlying their incredible survival abilities. Recent analyses showed that the resistance to ionizing radiation (IR) in the archaeon Halobacterium salinarum is dependent upon Mn-antioxidant complexes responsible for the scavenging of reactive oxygen species (ROS) generated by radiation. Here we examined the role of the compatible solutes trehalose, mannosylglycerate, and di-myo-inositol phosphate in the radiation resistance of aerobic and anaerobic thermophiles. We found that the IR resistance of the thermophilic bacteria Rubrobacter xylanophilus and Rubrobacter radiotolerans was highly correlated to the accumulation of high intracellular concentration of trehalose in association with Mn, supporting the model of Mn(2+)-dependent ROS scavenging in the aerobes. In contrast, the hyperthermophilic archaea Thermococcus gammatolerans and Pyrococcus furiosus did not contain significant amounts of intracellular Mn, and we found no significant antioxidant activity from mannosylglycerate and di-myo-inositol phosphate in vitro. We therefore propose that the low levels of IR-generated ROS under anaerobic conditions combined with highly constitutively expressed detoxification systems in these anaerobes are key to their radiation resistance and circumvent the need for the accumulation of Mn-antioxidant complexes in the cell.

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

Science.gov (United States)

Prevost, S; Andre, S; Remize, F

2010-12-01

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

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

OpenAIRE

Ahring, Birgitte K.; Westermann, Peter

1987-01-01

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

Enhanced start-up of anaerobic facultatively autotrophic biocathodes in bioelectrochemical systems

KAUST Repository

Zaybak, Zehra

2013-12-01

Biocathodes in bioelectrochemical systems (BESs) can be used to convert CO2 into diverse organic compounds through a process called microbial electrosynthesis. Unfortunately, start-up of anaerobic biocathodes in BESs is a difficult and time consuming process. Here, a pre-enrichment method was developed to improve start-up of anaerobic facultatively autotrophic biocathodes capable of using cathodes as the electron donor (electrotrophs) and CO2 as the electron acceptor. Anaerobic enrichment of bacteria from freshwater bog sediment samples was first performed in batch cultures fed with glucose and then used to inoculate BES cathode chambers set at -0.4V (versus a standard hydrogen electrode; SHE). After two weeks of heterotrophic operation of BESs, CO2 was provided as the sole electron acceptor and carbon source. Consumption of electrons from cathodes increased gradually and was sustained for about two months in concert with a significant decrease in cathode chamber headspace CO2. The maximum current density consumed was -34±4mA/m2. Biosynthesis resulted in organic compounds that included butanol, ethanol, acetate, propionate, butyrate, and hydrogen gas. Bacterial community analyses based on 16S rRNA gene clone libraries revealed Trichococcus palustris DSM 9172 (99% sequence identity) as the prevailing species in biocathode communities, followed by Oscillibacter sp. and Clostridium sp. Isolates from autotrophic cultivation were most closely related to Clostridium propionicum (99% sequence identity; ZZ16), Clostridium celerecrescens (98-99%; ZZ22, ZZ23), Desulfotomaculum sp. (97%; ZZ21), and Tissierella sp. (98%; ZZ25). This pre-enrichment procedure enables simplified start-up of anaerobic biocathodes for applications such as electrofuel production by facultatively autotrophic electrotrophs. © 2013 Elsevier B.V.

Enhanced start-up of anaerobic facultatively autotrophic biocathodes in bioelectrochemical systems

KAUST Repository

Zaybak, Zehra; Pisciotta, John M.; Tokash, Justin C.; Logan, Bruce E.

2013-01-01

Biocathodes in bioelectrochemical systems (BESs) can be used to convert CO2 into diverse organic compounds through a process called microbial electrosynthesis. Unfortunately, start-up of anaerobic biocathodes in BESs is a difficult and time consuming process. Here, a pre-enrichment method was developed to improve start-up of anaerobic facultatively autotrophic biocathodes capable of using cathodes as the electron donor (electrotrophs) and CO2 as the electron acceptor. Anaerobic enrichment of bacteria from freshwater bog sediment samples was first performed in batch cultures fed with glucose and then used to inoculate BES cathode chambers set at -0.4V (versus a standard hydrogen electrode; SHE). After two weeks of heterotrophic operation of BESs, CO2 was provided as the sole electron acceptor and carbon source. Consumption of electrons from cathodes increased gradually and was sustained for about two months in concert with a significant decrease in cathode chamber headspace CO2. The maximum current density consumed was -34±4mA/m2. Biosynthesis resulted in organic compounds that included butanol, ethanol, acetate, propionate, butyrate, and hydrogen gas. Bacterial community analyses based on 16S rRNA gene clone libraries revealed Trichococcus palustris DSM 9172 (99% sequence identity) as the prevailing species in biocathode communities, followed by Oscillibacter sp. and Clostridium sp. Isolates from autotrophic cultivation were most closely related to Clostridium propionicum (99% sequence identity; ZZ16), Clostridium celerecrescens (98-99%; ZZ22, ZZ23), Desulfotomaculum sp. (97%; ZZ21), and Tissierella sp. (98%; ZZ25). This pre-enrichment procedure enables simplified start-up of anaerobic biocathodes for applications such as electrofuel production by facultatively autotrophic electrotrophs. © 2013 Elsevier B.V.

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

International Nuclear Information System (INIS)

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

2017-01-01

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

Sensitivity of clostridium acetobutylicum to oxygen and ionizing radiation

International Nuclear Information System (INIS)

Sozer, A.C.; Adler, H.I.; Machanoff, R.; Haney, S.

1984-01-01

The authors are studying the sensitivity of four strains of the obligate anaerobe, Clostridium acetobutylicum, to oxygen and ionizing radiation. Anaerobic bacteria are useful for such studies because of the absence of elaborate oxygen detoxification mechanisms that are found in aerobes. Their experiments make use of sterile membrane fragments from Escherichia coli that rapidly remove molecular oxygen from media and permit growth of anaerobes without the use of reducing agents or anaerobic chambers. Of the four strains examined for sensitivity to ionizing radiation under anaerobic conditions, one has an LD/sub 50/ of -- 25 krads and the others have an LD/sub 50/ of -- 7 krads. The radiation resistant strain is also relatively resistant to oxygen exposure. Sensitivity to oxygen was determined by diluting cells in buffer at 28 0 and bubbling with air. An exposure to air for 40 min induced only slight inactivation in the radiation resistant strain. All strains are capable of removing oxygen from complex media but there is no apparent correlation between this oxygen consuming reaction and inactivation by either oxygen or radiation

Enhanced abiotic and biotic contributions to dechlorination of pentachlorophenol during Fe(III) reduction by an iron-reducing bacterium Clostridium beijerinckii Z

Energy Technology Data Exchange (ETDEWEB)

Xu, Yan [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058 (China); He, Yan, E-mail: yhe2006@zju.edu.cn [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058 (China); Feng, Xiaoli [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058 (China); Liang, Luyi [Experiment Teaching Center for Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058 (China); Xu, Jianming, E-mail: jmxu@zju.edu.cn [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058 (China); Brookes, Philip C.; Wu, Jianjun [College of Environmental and Natural Resource Sciences, Zhejiang Provincial Key Laboratory of Subtropical Soil and Plant Nutrition, Zhejiang University, Hangzhou 310058 (China)

2014-03-01

A novel Fe(III) reducing bacterium, Clostridium beijerinckii Z, was isolated from glucose amended paddy slurries, and shown to dechlorinate pentachlorophenol (PCP). Fifty percent of added PCP was removed by C. beijerinckii Z alone, which increased to 83% in the presence of both C. beijerinckii Z and ferrihydrite after 11 days of incubation. Without C. beijerinckii Z, the surface-bound Fe(II) also abiotically dechlorinated more than 40% of the added PCP. This indicated that the biotic dechlorination by C. beijerinckii Z is a dominant process causing PCP transformation through anaerobic dechlorination, and that the dechlorination rates can be accelerated by simultaneous reduction of Fe(III). A biochemical electron transfer coupling process between sorbed Fe(II) produced by C. beijerinckii Z and reductive dehalogenation is a possible mechanism. This finding increases our knowledge of the role of Fe(III) reducing genera of Clostridium in dechlorinating halogenated organic pollutants, such as PCP, in anaerobic paddy soils. - Highlights: • A novel Fe(III) reducing bacterium Clostridium beijerinckii Z was isolated and could dechlorinate pentachlorophenol. • Anaerobic transformation of PCP by C. beijerinckii Z could be accelerated by simultaneous reduction of Fe(III). • Biochemical electron transfer coupling between Fe redox cycling and reductive dechlorination was the mechanism involved. • The finding increases our knowledge of Clostridium sp. regarding their multiple functions for dechlorinating pollutants.

Enhanced abiotic and biotic contributions to dechlorination of pentachlorophenol during Fe(III) reduction by an iron-reducing bacterium Clostridium beijerinckii Z

International Nuclear Information System (INIS)

Xu, Yan; He, Yan; Feng, Xiaoli; Liang, Luyi; Xu, Jianming; Brookes, Philip C.; Wu, Jianjun

2014-01-01

A novel Fe(III) reducing bacterium, Clostridium beijerinckii Z, was isolated from glucose amended paddy slurries, and shown to dechlorinate pentachlorophenol (PCP). Fifty percent of added PCP was removed by C. beijerinckii Z alone, which increased to 83% in the presence of both C. beijerinckii Z and ferrihydrite after 11 days of incubation. Without C. beijerinckii Z, the surface-bound Fe(II) also abiotically dechlorinated more than 40% of the added PCP. This indicated that the biotic dechlorination by C. beijerinckii Z is a dominant process causing PCP transformation through anaerobic dechlorination, and that the dechlorination rates can be accelerated by simultaneous reduction of Fe(III). A biochemical electron transfer coupling process between sorbed Fe(II) produced by C. beijerinckii Z and reductive dehalogenation is a possible mechanism. This finding increases our knowledge of the role of Fe(III) reducing genera of Clostridium in dechlorinating halogenated organic pollutants, such as PCP, in anaerobic paddy soils. - Highlights: • A novel Fe(III) reducing bacterium Clostridium beijerinckii Z was isolated and could dechlorinate pentachlorophenol. • Anaerobic transformation of PCP by C. beijerinckii Z could be accelerated by simultaneous reduction of Fe(III). • Biochemical electron transfer coupling between Fe redox cycling and reductive dechlorination was the mechanism involved. • The finding increases our knowledge of Clostridium sp. regarding their multiple functions for dechlorinating pollutants

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

Directory of Open Access Journals (Sweden)

Benjamin M Zeldes

2015-11-01

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

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

Science.gov (United States)

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

2015-01-01

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

Vermin on pig farms are vectors for Clostridium difficile PCR ribotypes 078 and 045

NARCIS (Netherlands)

Burt, S.A.; Siemeling, L.; Kuijper, E.J.; Lipman, L.J.A.

2012-01-01

Clostridium difficile is a gram positive, spore forming, toxin producing, anaerobic bacteria and an opportunistic pathogen for Man and many animal species, causing diarrhea in young piglets. Piglets probably become colonized from the environment. To investigate the possible spread and transmission

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

NARCIS (Netherlands)

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

2003-01-01

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

Antimicrobial susceptibility of clinical isolates of anaerobic bacteria in Ontario, 2010-2011.

Science.gov (United States)

Marchand-Austin, Alex; Rawte, Prasad; Toye, Baldwin; Jamieson, Frances B; Farrell, David J; Patel, Samir N

2014-08-01

The local epidemiology of antimicrobial susceptibility patterns in anaerobic bacteria is important in guiding the empiric treatment of infections. However, susceptibility data are very limited on anaerobic organisms, particularly among non-Bacteroides organisms. To determine susceptibility profiles of clinically-significant anaerobic bacteria in Ontario Canada, anaerobic isolates from sterile sites submitted to Public Health Ontario Laboratory (PHOL) for identification and susceptibility testing were included in this study. Using the E-test method, isolates were tested for various antimicrobials including, penicillin, cefoxitin, clindamycin, meropenem, piperacillin-tazobactam and metronidazole. The MIC results were interpreted based on guidelines published by Clinical and Laboratory Standards Institute. Of 2527 anaerobic isolates submitted to PHOL, 1412 were either from sterile sites or bronchial lavage, and underwent susceptibility testing. Among Bacteroides fragilis, 98.2%, 24.7%, 1.6%, and 1.2% were resistant to penicillin, clindamycin, piperacillin-tazobactam, and metronidazole, respectively. Clostridium perfringens was universally susceptible to penicillin, piperacillin-tazobactam, and meropenem, whereas 14.2% of other Clostridium spp. were resistant to penicillin. Among Gram-positive anaerobes, Actinomyces spp., Parvimonas micra and Propionibacterium spp. were universally susceptible to β-lactams. Eggerthella spp., Collinsella spp., and Eubacterium spp. showed variable resistance to penicillin. Among Gram-negative anaerobes, Fusobacterium spp., Prevotella spp., and Veillonella spp. showed high resistance to penicillin but were universally susceptible to meropenem and piperacillin-tazobactam. The detection of metronidazole resistant B. fragilis is concerning as occurrence of these isolates is extremely rare. These data highlight the importance of ongoing surveillance to provide clinically relevant information to clinicians for empiric management of

Anaerobic carboxydotrophic bacteria in geothermal springs identified using stable isotope probing

Directory of Open Access Journals (Sweden)

Allyson Lee Brady

2015-09-01

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

Taxonogenomic description of four new Clostridium species isolated from human gut: ‘Clostridium amazonitimonense’, ‘Clostridium merdae’, ‘Clostridium massilidielmoense’ and ‘Clostridium nigeriense’

Directory of Open Access Journals (Sweden)

M.T. Alou

2018-01-01

Full Text Available Culturomics investigates microbial diversity of the human microbiome by combining diversified culture conditions, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and 16S rRNA gene identification. The present study allowed identification of four putative new Clostridium sensu stricto species: ‘Clostridium amazonitimonense’ strain LF2T, ‘Clostridium massilidielmoense’ strain MT26T, ‘Clostridium nigeriense’ strain Marseille-P2414T and ‘Clostridium merdae’ strain Marseille-P2953T, which we describe using the concept of taxonogenomics. We describe the main characteristics of each bacterium and present their complete genome sequence and annotation. Keywords: ‘Clostridium amazonitimonense’, ‘Clostridium massilidielmoense’, ‘Clostridium merdae’, ‘Clostridium nigeriense’, culturomics, emerging bacteria, human microbiota, taxonogenomics

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

DEFF Research Database (Denmark)

Angelidaki, Irini; Treu, Laura; Campanaro, Stefano

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

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

Science.gov (United States)

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

2016-02-01

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

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

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Olson Daniel G

2012-05-01

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

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

Directory of Open Access Journals (Sweden)

Alexander G. Elcheninov

2017-11-01

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

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

Science.gov (United States)

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

2017-01-01

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

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

NARCIS (Netherlands)

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

2003-01-01

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

Plant pathogenic anaerobic bacteria use aromatic polyketides to access aerobic territory.

Science.gov (United States)

Shabuer, Gulimila; Ishida, Keishi; Pidot, Sacha J; Roth, Martin; Dahse, Hans-Martin; Hertweck, Christian

2015-11-06

Around 25% of vegetable food is lost worldwide because of infectious plant diseases, including microbe-induced decay of harvested crops. In wet seasons and under humid storage conditions, potato tubers are readily infected and decomposed by anaerobic bacteria (Clostridium puniceum). We found that these anaerobic plant pathogens harbor a gene locus (type II polyketide synthase) to produce unusual polyketide metabolites (clostrubins) with dual functions. The clostrubins, which act as antibiotics against other microbial plant pathogens, enable the anaerobic bacteria to survive an oxygen-rich plant environment. Copyright © 2015, American Association for the Advancement of Science.

Bacterial ecology of abattoir wastewater treated by an anaerobic digestor

Directory of Open Access Journals (Sweden)

Linda Jabari

2016-03-01

Full Text Available Abstract Wastewater from an anaerobic treatment plant at a slaughterhouse was analysed to determine the bacterial biodiversity present. Molecular analysis of the anaerobic sludge obtained from the treatment plant showed significant diversity, as 27 different phyla were identified. Firmicutes, Proteobacteria, Bacteroidetes, Thermotogae, Euryarchaeota (methanogens, and msbl6 (candidate division were the dominant phyla of the anaerobic treatment plant and represented 21.7%, 18.5%, 11.5%, 9.4%, 8.9%, and 8.8% of the total bacteria identified, respectively. The dominant bacteria isolated were Clostridium, Bacteroides, Desulfobulbus, Desulfomicrobium, Desulfovibrio and Desulfotomaculum. Our results revealed the presence of new species, genera and families of microorganisms. The most interesting strains were characterised. Three new bacteria involved in anaerobic digestion of abattoir wastewater were published.

First described case of prosthetic joint infection with Clostridium disporicum.

Science.gov (United States)

McBride, Joseph A; Sterkel, Alana K; Rehrauer, William M; Smith, Jeannina A

2017-12-01

An orthopedic hardware infection with Clostridium disporicum is described. C. disporicum is a gram positive anaerobic bacillus which can contain two subterminal spores. C. disporicum had not previously been reported in musculoskeletal infections. Gram stains demonstrating gram positive bacilli with two subterminal spores should alert practitioners to the possibility of C. disporicum infection. Published by Elsevier Ltd.

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

Science.gov (United States)

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

2015-01-01

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

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

Science.gov (United States)

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

2015-10-01

Bio-hydrogen production from dry thermophilic anaerobic co-digestion (55°C and 20% total solids) of organic fraction of municipal solid waste (OFMSW) and food waste (FW) was studied. OFMSW coming from mechanical-biological treatment plants (MBT plants) presents a low organic matter concentration. However, FW has a high organic matter content but several problems by accumulation of volatile fatty acids (VFAs) and system acidification. Tests were conducted using a mixture ratio of 80:20 (OFSMW:FW), to avoid the aforementioned problems. Different solid retention times (SRTs) - 6.6, 4.4, 2.4 and 1.9 days - were tested. It was noted that addition of food waste enhances the hydrogen production in all the SRTs tested. Best results were obtained at 1.9-day SRT. It was observed an increase from 0.64 to 2.51 L H2/L(reactor) day in hydrogen productivity when SRTs decrease from 6.6 to 1.9 days. However, the hydrogen yield increases slightly from 33.7 to 38 mL H2/gVS(added). Copyright © 2015 Elsevier Ltd. All rights reserved.

Purification and characterization of an H2O-forming NADH oxidase from Clostridium aminovalericum: existence of an oxygen-detoxifying enzyme in an obligate anaerobic bacteria.

Science.gov (United States)

Kawasaki, Shinji; Ishikura, Jun; Chiba, Daisuke; Nishino, Tomoko; Niimura, Youichi

2004-04-01

Clostridium aminovalericum, an obligate anaerobe, is unable to form colonies on PYD agar plates in the presence of 1% O(2). When grown anaerobically in PYD liquid medium, the strain can continue normal growth after the shift from anoxic (sparged with O(2)-free N(2) carrier-gas) to microoxic (sparged with 3% O(2)/97% N(2) mixed carrier-gas) growth conditions in the mid exponential phase (OD(660)=1.0). When the strain grew under 3% O(2)/97% N(2), the medium remains anoxic. Thirty minutes after beginning aeration with 3% O(2), the activity of NADH oxidase in cell-free extracts increased more than five-fold from the level before aeration. We purified NADH oxidase to determine the characteristics of this enzyme in an obligate anaerobe. The purified NADH oxidase dominated the NADH oxidase activity detected in cell-free extracts. The enzyme is a homotetramer composed of a subunit with a molecular mass of 45 kDa. The enzyme shows a spectrum typical of a flavoprotein, and flavin adenine dinucleotide (FAD) was identified as a cofactor. The final product of NADH oxidation was H(2)O, and the estimated K(m) for oxygen was 61.9 microM. These data demonstrate that an O(2)-response enzyme that is capable of detoxifying oxygen to water exists in C. aminovalericum.

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

Science.gov (United States)

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

2010-05-01

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

Gaining electricity from in situ oxidation of hydrogen produced by fermentative cellulose degradation.

Science.gov (United States)

Niessen, J; Schröder, U; Harnisch, F; Scholz, F

2005-01-01

To exploit the fermentative hydrogen generation and direct hydrogen oxidation for the generation of electric current from the degradation of cellulose. Utilizing the metabolic activity of the mesophilic anaerobe Clostridium cellulolyticum and the thermophilic Clostridium thermocellum we show that electricity generation is possible from cellulose fermentation. The current generation is based on an in situ oxidation of microbially synthesized hydrogen at platinum-poly(tetrafluoroaniline) (Pt-PTFA) composite electrodes. Current densities of 130 mA l(-1) (with 3 g cellulose per litre medium) were achieved in poised potential experiments under batch and semi-batch conditions. The presented results show that electricity generation is possible by the in situ oxidation of hydrogen, product of the anaerobic degradation of cellulose by cellulolytic bacteria. For the first time, it is shown that an insoluble complex carbohydrate like cellulose can be used for electricity generation in a microbial fuel cell. The concept represents a first step to the utilization of macromolecular biomass components for microbial electricity generation.

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

KAUST Repository

Oosterkamp, Margreet J.

2016-06-06

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

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

Science.gov (United States)

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

2016-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

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

Development of Vaccines to Prevent Wound Infections due to Anaerobic Bacteria

Science.gov (United States)

1980-08-01

containing an inoculum that included anaerobes ( Eubacterium , Clostridium, Bacteroides, Peptococcus, and Fusobacterium) and aerobes (E. coli, enterococcus) in a...serogroups of the Bacteroides spp . based on 0-antigens have been described. (11-13) Type-specific antisera raised in rabbits against twenty distinct

Saponification of fatty slaughterhouse wastes for enhancing anaerobic biodegradability.

Science.gov (United States)

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

2009-08-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Vandevoorde, L; Verstraete, W

1987-08-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2008-10-15

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

Immobilized anaerobic fermentation for bio-fuel production by Clostridium co-culture.

Science.gov (United States)

Xu, Lei; Tschirner, Ulrike

2014-08-01

Clostridium thermocellum/Clostridium thermolacticum co-culture fermentation has been shown to be a promising way of producing ethanol from several carbohydrates. In this research, immobilization techniques using sodium alginate and alkali pretreatment were successfully applied on this co-culture to improve the bio-ethanol fermentation performance during consolidated bio-processing (CBP). The ethanol yield obtained increased by over 60 % (as a percentage of the theoretical maximum) as compared to free cell fermentation. For cellobiose under optimized conditions, the ethanol yields were approaching about 85 % of the theoretical efficiency. To examine the feasibility of this immobilization co-culture on lignocellulosic biomass conversion, untreated and pretreated aspen biomasses were also used for fermentation experiments. The immobilized co-culture shows clear benefits in bio-ethanol production in the CBP process using pretreated aspen. With a 3-h, 9 % NaOH pretreatment, the aspen powder fermentation yields approached 78 % of the maximum theoretical efficiency, which is almost twice the yield of the untreated aspen fermentation.

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

Science.gov (United States)

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

2010-02-01

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

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

Science.gov (United States)

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

2013-05-01

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

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

Science.gov (United States)

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

2013-10-01

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

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

DEFF Research Database (Denmark)

Uellendahl, Hinrich; Ahring, Birgitte Kiær

An integrated biorefinery concept for 2nd generation bioethanol production together with biogas production from the fermentation effluent was tested in pilot-scale. The pilot plant comprised pretreatment, enzymatic hydrolysis, hexose and pentose fermentation into ethanol and anaerobic digestion......-VS/(m3•d) a methane yield of 340 L/kg-VS was achieved for thermophilic operation while 270 L/kg-VS was obtained under mesophilic conditions. Thermophilic operation was, however, less robust towards further increase of the loading rate and for loading rates higher than 5 kg-VS/(m3•d) the yield was higher...... for mesophilic than for thermophilic operation. The effluent from the ethanol fermentation showed no signs of toxicity to the anaerobic microorganisms. Implementation of the biogas production from the fermentation effluent accounted for about 30% higher biofuels yield in the biorefinery compared to a system...

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

Science.gov (United States)

Ge, Huoqing; Batstone, Damien; Keller, Jurg

2016-01-01

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

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

DEFF Research Database (Denmark)

Wu, Ying; Cui, Erping; Zuo, Yiru

2016-01-01

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

Metaproteomics of cellulose methanisation under thermophilic conditions reveals a surprisingly high proteolytic activity.

Science.gov (United States)

Lü, Fan; Bize, Ariane; Guillot, Alain; Monnet, Véronique; Madigou, Céline; Chapleur, Olivier; Mazéas, Laurent; He, Pinjing; Bouchez, Théodore

2014-01-01

Cellulose is the most abundant biopolymer on Earth. Optimising energy recovery from this renewable but recalcitrant material is a key issue. The metaproteome expressed by thermophilic communities during cellulose anaerobic digestion was investigated in microcosms. By multiplying the analytical replicates (65 protein fractions analysed by MS/MS) and relying solely on public protein databases, more than 500 non-redundant protein functions were identified. The taxonomic community structure as inferred from the metaproteomic data set was in good overall agreement with 16S rRNA gene tag pyrosequencing and fluorescent in situ hybridisation analyses. Numerous functions related to cellulose and hemicellulose hydrolysis and fermentation catalysed by bacteria related to Caldicellulosiruptor spp. and Clostridium thermocellum were retrieved, indicating their key role in the cellulose-degradation process and also suggesting their complementary action. Despite the abundance of acetate as a major fermentation product, key methanogenesis enzymes from the acetoclastic pathway were not detected. In contrast, enzymes from the hydrogenotrophic pathway affiliated to Methanothermobacter were almost exclusively identified for methanogenesis, suggesting a syntrophic acetate oxidation process coupled to hydrogenotrophic methanogenesis. Isotopic analyses confirmed the high dominance of the hydrogenotrophic methanogenesis. Very surprising was the identification of an abundant proteolytic activity from Coprothermobacter proteolyticus strains, probably acting as scavenger and/or predator performing proteolysis and fermentation. Metaproteomics thus appeared as an efficient tool to unravel and characterise metabolic networks as well as ecological interactions during methanisation bioprocesses. More generally, metaproteomics provides direct functional insights at a limited cost, and its attractiveness should increase in the future as sequence databases are growing exponentially.

Clostridium geopurificans strain MJ1 sp. nov., a strictly anaerobic bacterium that grows via fermentation and reduces the cyclic nitramine explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX).

Science.gov (United States)

Kwon, Man Jae; Wei, Na; Millerick, Kayleigh; Popovic, Jovan; Finneran, Kevin

2014-06-01

A fermentative, non-spore forming, motile, rod-shaped bacterium, designated strain MJ1(T), was isolated from an RDX contaminated aquifer at a live-fire training site in Northwest NJ, United States. On the basis of 16S rRNA gene sequencing and DNA base composition, strain MJ1(T) was assigned to the Firmicutes. The DNA G+C content was 42.8 mol%. Fermentative growth was supported by glucose and citrate in a defined basal medium. The bacterium is a strict anaerobe that grows between at pH 6.0 and pH 8.0 and 18 and 37 °C. The culture did not grow with hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) as the electron acceptor or mineralize RDX under these conditions. However, MJ1(T) transformed RDX into MNX, methylenedinitramine, formaldehyde, formate, ammonium, nitrous oxide, and nitrate. The nearest phylogenetic relative with a validly published name was Desulfotomaculum guttoideum (95 % similarity). However, MJ1(T) was also related to Clostridium celerecrescens DSM 5628 (95 %), Clostridium indolis DSM 755 (94 %), and Clostridium sphenoides DSM 632 (94 %). DNA:DNA hybridization with these strains was between 6.7 and 58.7 percent. The dominant cellular fatty acids (greater than 5 % of the total, which was 99.0 % recovery) were 16:0 fatty acid methyl ester (FAME) (32.12 %), 18:1cis 11 dimethyl acetal (DMA) (16.47 %), 16:1cis 9 DMA (10.28 %), 16:1cis 9 FAME (8.10 %), and 18:1cis 9 DMA (5.36 %). On the basis of morphological, physiological, and phylogenetic data, Clostridium geopurificans is proposed as a new species in genus Clostridium, with strain MJ1(T) as the type strain.

Clostridium perfringens bacteremia caused by choledocholithiasis in the absence of gallbladder stones

OpenAIRE

Atia, Antwan; Raiyani, Tejas; Patel, Pranav; Patton, Robert; Young, Mark

2012-01-01

A 67-years-old male presented with periumbilical abdominal pain, fever and jaundice. His anaerobic blood culture was positive for clostridium perfringens. Computed tomogram scan of the abdomen and abdominal ultrasound showed normal gallbladder and common bile duct (CBD). Subsequently magnetic resonance cholangiopancreaticogram showed choledocholithiasis. Endoscopic retrograde cholangiopancreaticogramwith sphincterotomy and CBD stone extraction was performed. The patient progressively improved...

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

Science.gov (United States)

Sensai, P; Thangamani, A; Visvanathan, C

2014-01-01

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

Thermophilic and alkalophilic xylanases from several Dictyoglomus isolates

Energy Technology Data Exchange (ETDEWEB)

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

1992-10-01

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

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

NARCIS (Netherlands)

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

2012-01-01

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

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

Science.gov (United States)

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

2013-02-01

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

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

Science.gov (United States)

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

2016-01-01

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

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

KAUST Repository

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

2017-01-01

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

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

KAUST Repository

Ghanimeh, Sophia A.

2017-12-07

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

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

Science.gov (United States)

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

2013-01-01

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

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

Science.gov (United States)

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

2010-02-01

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

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

Science.gov (United States)

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

2010-01-01

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

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

NARCIS (Netherlands)

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

2018-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Stoll, U.

1988-01-01

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

Dissimilatory oxidation and reduction of elemental sulfur in thermophilic archaea.

Science.gov (United States)

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

2004-02-01

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

Bacterial ecology of abattoir wastewater treated by an anaerobic digestor.

Science.gov (United States)

Jabari, Linda; Gannoun, Hana; Khelifi, Eltaief; Cayol, Jean-Luc; Godon, Jean-Jacques; Hamdi, Moktar; Fardeau, Marie-Laure

2016-01-01

Wastewater from an anaerobic treatment plant at a slaughterhouse was analysed to determine the bacterial biodiversity present. Molecular analysis of the anaerobic sludge obtained from the treatment plant showed significant diversity, as 27 different phyla were identified. Firmicutes, Proteobacteria, Bacteroidetes, Thermotogae, Euryarchaeota (methanogens), and msbl6 (candidate division) were the dominant phyla of the anaerobic treatment plant and represented 21.7%, 18.5%, 11.5%, 9.4%, 8.9%, and 8.8% of the total bacteria identified, respectively. The dominant bacteria isolated were Clostridium, Bacteroides, Desulfobulbus, Desulfomicrobium, Desulfovibrio and Desulfotomaculum. Our results revealed the presence of new species, genera and families of microorganisms. The most interesting strains were characterised. Three new bacteria involved in anaerobic digestion of abattoir wastewater were published. Copyright © 2015 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Formation and characterization of non-growth states in Clostridium thermocellum: spores and L-forms

Directory of Open Access Journals (Sweden)

Mearls Elizabeth B

2012-08-01

Full Text Available Abstract Background Clostridium thermocellum is an anaerobic thermophilic bacterium that exhibits high levels of cellulose solublization and produces ethanol as an end product of its metabolism. Using cellulosic biomass as a feedstock for fuel production is an attractive prospect, however, growth arrest can negatively impact ethanol production by fermentative microorganisms such as C. thermocellum. Understanding conditions that lead to non-growth states in C. thermocellum can positively influence process design and culturing conditions in order to optimize ethanol production in an industrial setting. Results We report here that Clostridium thermocellum ATCC 27405 enters non-growth states in response to specific growth conditions. Non-growth states include the formation of spores and a L-form-like state in which the cells cease to grow or produce the normal end products of metabolism. Unlike other sporulating organisms, we did not observe sporulation of C. thermocellum in low carbon or nitrogen environments. However, sporulation did occur in response to transfers between soluble and insoluble substrates, resulting in approximately 7% mature spores. Exposure to oxygen caused a similar sporulation response. Starvation conditions during continuous culture did not result in spore formation, but caused the majority of cells to transition to a L-form state. Both spores and L-forms were determined to be viable. Spores exhibited enhanced survival in response to high temperature and prolonged storage compared to L-forms and vegetative cells. However, L-forms exhibited faster recovery compared to both spores and stationary phase cells when cultured in rich media. Conclusions Both spores and L-forms cease to produce ethanol, but provide other advantages for C. thermocellum including enhanced survival for spores and faster recovery for L-forms. Understanding the conditions that give rise to these two different non-growth states, and the implications that

Biological hydrogen production from biomass by thermophilic bacteria

International Nuclear Information System (INIS)

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

2006-01-01

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

Hybrid alkali-hydrodynamic disintegration of waste-activated sludge before two-stage anaerobic digestion process.

Science.gov (United States)

Grübel, Klaudiusz; Suschka, Jan

2015-05-01

The first step of anaerobic digestion, the hydrolysis, is regarded as the rate-limiting step in the degradation of complex organic compounds, such as waste-activated sludge (WAS). The aim of lab-scale experiments was to pre-hydrolyze the sludge by means of low intensive alkaline sludge conditioning before applying hydrodynamic disintegration, as the pre-treatment procedure. Application of both processes as a hybrid disintegration sludge technology resulted in a higher organic matter release (soluble chemical oxygen demand (SCOD)) to the liquid sludge phase compared with the effects of processes conducted separately. The total SCOD after alkalization at 9 pH (pH in the range of 8.96-9.10, SCOD = 600 mg O2/L) and after hydrodynamic (SCOD = 1450 mg O2/L) disintegration equaled to 2050 mg/L. However, due to the synergistic effect, the obtained SCOD value amounted to 2800 mg/L, which constitutes an additional chemical oxygen demand (COD) dissolution of about 35 %. Similarly, the synergistic effect after alkalization at 10 pH was also obtained. The applied hybrid pre-hydrolysis technology resulted in a disintegration degree of 28-35%. The experiments aimed at selection of the most appropriate procedures in terms of optimal sludge digestion results, including high organic matter degradation (removal) and high biogas production. The analyzed soft hybrid technology influenced the effectiveness of mesophilic/thermophilic anaerobic digestion in a positive way and ensured the sludge minimization. The adopted pre-treatment technology (alkalization + hydrodynamic cavitation) resulted in 22-27% higher biogas production and 13-28% higher biogas yield. After two stages of anaerobic digestion (mesophilic conditions (MAD) + thermophilic anaerobic digestion (TAD)), the highest total solids (TS) reduction amounted to 45.6% and was received for the following sample at 7 days MAD + 17 days TAD. About 7% higher TS reduction was noticed compared with the sample after 9

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

Science.gov (United States)

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

2016-07-01

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

My Lifelong Passion for Biochemistry and Anaerobic Microorganisms.

Science.gov (United States)

Thauer, Rudolf Kurt

2015-01-01

Early parental influence led me first to medical school, but after developing a passion for biochemistry and sensing the need for a deeper foundation, I changed to chemistry. During breaks between semesters, I worked in various biochemistry labs to acquire a feeling for the different areas of investigation. The scientific puzzle that fascinated me most was the metabolism of the anaerobic bacterium Clostridium kluyveri, which I took on in 1965 in Karl Decker's lab in Freiburg, Germany. I quickly realized that little was known about the biochemistry of strict anaerobes such as clostridia, methanogens, acetogens, and sulfate-reducing bacteria and that these were ideal model organisms to study fundamental questions of energy conservation, CO2 fixation, and the evolution of metabolic pathways. My passion for anaerobes was born then and is unabated even after 50 years of study.

Physiology of thermophilic bacteria

Energy Technology Data Exchange (ETDEWEB)

Ljungdahl, L G

1979-01-01

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

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

Science.gov (United States)

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

2013-12-01

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

Composition of cellulase complex of Clostridium thermocellum

Energy Technology Data Exchange (ETDEWEB)

Golovchenko, N P; Chuvil' skaya, N A; Akimenko, V K

1985-01-01

It is thought that the anaerobic thermophilic cellulolytic bacterium C. thermocellum has the potential for direct industrial bioconversion of cellulose into ethanol. Therefore, much attention has been given to the study of the cellulolytic properties of the culture and to the characteristics of the cellulose complex, which is still not completely understood. Hence, the activity and location of various cellulolytic enzymes of C. thermocellum were determined. C. thermocellum has 6 known cellulolytic enzymes. Endoglucanase, cellobiohydrolase and exoglucosidase are extracellular enzymes (99-100 percent of the activity is located outside the cells) while cellulobiases, cellobiose phosphorylase and cellodextrine phosphorylase are inside the cells (80-90% of the activity). 25 references.

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

Science.gov (United States)

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

2017-03-01

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

Clostridium sordellii as a Cause of Fatal Septic Shock in a Child with Hemolytic Uremic Syndrome

Directory of Open Access Journals (Sweden)

Rebekah Beyers

2014-01-01

Full Text Available Clostridium sordellii is a toxin producing ubiquitous gram-positive anaerobe, mainly associated with trauma, soft tissue skin infections, and gynecologic infection. We report a unique case of a new strain of Clostridium sordellii (not present in the Center for Disease Control (CDC database infection induced toxic shock syndrome in a previously healthy two-year-old male with colitis-related hemolytic uremic syndrome (HUS. The patient presented with dehydration, vomiting, and bloody diarrhea. He was transferred to the pediatric critical care unit (PICU for initiation of peritoneal dialysis (PD. Due to increased edema and intolerance of PD, he was transitioned to hemodialysis through a femoral vascular catheter. He subsequently developed severe septic shock with persistent leukocytosis and hypotension, resulting in subsequent death. Stool culture confirmed Shiga toxin producing Escherichia coli 0157:H7. A blood culture was positively identified for Clostridium sordellii. Clostridium sordelli is rarely reported in children; to our knowledge this is the first case described in a pediatric patient with HUS.

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

DEFF Research Database (Denmark)

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

2005-01-01

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

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

DEFF Research Database (Denmark)

Hartmann, H.; Ahring, Birgitte Kiær

2006-01-01

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

Properties of thermophilic microorganisms

International Nuclear Information System (INIS)

Ljungdahl, L.G.

1984-01-01

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

Improvement of anaerobic digestion of sludge

Energy Technology Data Exchange (ETDEWEB)

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

2003-07-01

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

The microbial ecology of anaerobic cellulose degradation in municipal waste landfill sites: evidence of a role for fibrobacters.

Science.gov (United States)

McDonald, James E; Houghton, James N I; Rooks, David J; Allison, Heather E; McCarthy, Alan J

2012-04-01

Cellulose is reputedly the most abundant organic polymer in the biosphere, yet despite the fundamental role of cellulolytic microorganisms in global carbon cycling and as potential sources of novel enzymes for biotechnology, their identity and ecology is not well established. Cellulose is a major component of landfill waste and its degradation is therefore a key feature of the anaerobic microbial decomposition process. Here, we targeted a number of taxa containing known cellulolytic anaerobes (members of the bacterial genus Fibrobacter, lineages of Clostridium clusters I, III, IV and XIV, and anaerobic fungi of the Neocallimastigales) in landfill leachate and colonized cellulose 'baits' via PCR and quantitative PCR (qPCR). Fibrobacter spp. and Clostridium clusters III, IV and XIV were detected in almost all leachate samples and cluster III and XIV clostridia were the most abundant (1-6% and 1-17% of total bacterial 16S rRNA gene copies respectively). Two landfill leachate microcosms were constructed to specifically assess those microbial communities that colonize and degrade cellulose substrates in situ. Scanning electron microscopy (SEM) of colonized cotton revealed extensive cellulose degradation in one microcosm, and Fibrobacter spp. and Clostridium cluster III represented 29% and 17%, respectively, of total bacterial 16S rRNA gene copies in the biofilm. Visible cellulose degradation was not observed in the second microcosm, and this correlated with negligible relative abundances of Clostridium cluster III and Fibrobacter spp. (≤ 0.1%), providing the first evidence that the novel fibrobacters recently detected in landfill sites and other non-gut environments colonize and degrade cellulose substrates in situ. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

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

DEFF Research Database (Denmark)

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

2017-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1994-01-01

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

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

KAUST Repository

Oosterkamp, Margreet

2016-01-01

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

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

Science.gov (United States)

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

2014-12-01

The objective of this study was to investigate the separate hydrogen and methane productions from cassava wastewater by using a two-stage upflow anaerobic sludge blanket (UASB) system under thermophilic operation. Recycle ratio of the effluent from methane bioreactor-to-feed flow rate was fixed at 1:1 and pH of hydrogen UASB unit was maintained at 5.5. At optimum COD loading rate of 90 kg/m3 d based on the feed COD load and hydrogen UASB volume, the produced gas from the hydrogen UASB unit mainly contained H2 and CO2 which provided the maximum hydrogen yield (54.22 ml H2/g COD applied) and specific hydrogen production rate (197.17 ml/g MLVSSd). At the same optimum COD loading rate, the produced gas from the methane UASB unit mainly contained CH4 and CO2 without H2 which were also consistent with the maximum methane yield (164.87 ml CH4/g COD applied) and specific methane production rate (356.31 ml CH4/g MLVSSd). The recycling operation minimized the use of NaOH for pH control in hydrogen UASB unit. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

2011-02-01

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

Anaerobic bacteraemia revisited: species and susceptibilities.

Science.gov (United States)

Ng, Lily S Y; Kwang, Lee Ling; Rao, Suma; Tan, Thean Yen

2015-01-01

This retrospective study was performed to evaluate the frequency of anaerobic bacteraemia over a 10-year period, and to provide updated antibiotic susceptibilities for the more clinically relevant anaerobes causing blood stream infection. Data were retrieved from the laboratory information system for the period 2003 to 2012. During this time, blood cultures were inoculated in Bactec™ Plus vials (BD, USA) and continuously monitored in the Bactec™ 9000 blood culture system (BD, USA). Anaerobic organisms were identified using commercial identification kits, predominantly API 20 A (bioMérieux, France) supplemented with Vitek ANC cards (bioMérieux, France) and AN-Ident discs (Oxoid, United Kingdom). A representative subset of isolates were retrieved from 2009 to 2011 and antimicrobial susceptibilities to penicillin, amoxicillin-clavulanate, clindamycin, imipenem, moxifloxacin, piperacillin-tazobactam and metronidazole were determined using the Etest method. Anaerobes comprised 4.1% of all positive blood culture with 727 obligate anaerobes recovered over the 10-year period, representing a positivity rate of 0.35%. The only significant change in anaerobe positivity rates occurred between 2003 and 2004, with an increase of 0.2%. The Bacteroides fragilis group (45%) were the predominant anaerobic pathogens, followed by Clostridium species (12%), Propioniobacterium species (11%) and Fusobacterium species (6%). The most active in vitro antibiotics were imipenem, piperacillin-tazobactam, amoxicillin-clavulanate and metronidazole, with susceptibilities of 95.0%, 93.3%, 90.8% and 90.8% respectively. Resistance was high to penicillin, clindamycin and moxifl oxacin. However, there were apparent differences for antibiotic susceptibilities between species. This study indicates that the anaerobes comprise a small but constant proportion of bloodstream isolates. Antibiotic resistance was high to some antibiotics, but metronidazole, the beta-lactam/beta-lactamase inhibitors and

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

International Nuclear Information System (INIS)

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

2012-01-01

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

Mechanism of quinolone resistance in anaerobic bacteria.

Science.gov (United States)

Oh, H; Edlund, C

2003-06-01

Several recently developed quinolones have excellent activity against a broad range of aerobic and anaerobic bacteria and are thus potential drugs for the treatment of serious anaerobic and mixed infections. Resistance to quinolones is increasing worldwide, but is still relatively infrequent among anaerobes. Two main mechanisms, alteration of target enzymes (gyrase and topoisomerase IV) caused by chromosomal mutations in encoding genes, or reduced intracellular accumulation due to increased efflux of the drug, are associated with quinolone resistance. These mechanisms have also been found in anaerobic species. High-level resistance to the newer broad-spectrum quinolones often requires stepwise mutations in target genes. The increasing emergence of resistance among anaerobes may be a consequence of previous widespread use of quinolones, which may have enriched first-step mutants in the intestinal tract. Quinolone resistance in the Bacteroides fragilis group strains is strongly correlated with amino acid substitutions at positions 82 and 86 in GyrA (equivalent to positions 83 and 87 of Escherichia coli). Several studies have indicated that B. fragilis group strains possess efflux pump systems that actively expel quinolones, leading to resistance. DNA gyrase seems also to be the primary target for quinolones in Clostridium difficile, since amino acid substitutions in GyrA and GyrB have been detected in resistant strains. To what extent other mechanisms, such as mutational events in other target genes or alterations in outer-membrane proteins, contribute to resistance among anaerobes needs to be further investigated.

Genome-scale metabolic analysis of Clostridium thermocellum for bioethanol production

Directory of Open Access Journals (Sweden)

Brooks J Paul

2010-03-01

Full Text Available Abstract Background Microorganisms possess diverse metabolic capabilities that can potentially be leveraged for efficient production of biofuels. Clostridium thermocellum (ATCC 27405 is a thermophilic anaerobe that is both cellulolytic and ethanologenic, meaning that it can directly use the plant sugar, cellulose, and biochemically convert it to ethanol. A major challenge in using microorganisms for chemical production is the need to modify the organism to increase production efficiency. The process of properly engineering an organism is typically arduous. Results Here we present a genome-scale model of C. thermocellum metabolism, iSR432, for the purpose of establishing a computational tool to study the metabolic network of C. thermocellum and facilitate efforts to engineer C. thermocellum for biofuel production. The model consists of 577 reactions involving 525 intracellular metabolites, 432 genes, and a proteomic-based representation of a cellulosome. The process of constructing this metabolic model led to suggested annotation refinements for 27 genes and identification of areas of metabolism requiring further study. The accuracy of the iSR432 model was tested using experimental growth and by-product secretion data for growth on cellobiose and fructose. Analysis using this model captures the relationship between the reduction-oxidation state of the cell and ethanol secretion and allowed for prediction of gene deletions and environmental conditions that would increase ethanol production. Conclusions By incorporating genomic sequence data, network topology, and experimental measurements of enzyme activities and metabolite fluxes, we have generated a model that is reasonably accurate at predicting the cellular phenotype of C. thermocellum and establish a strong foundation for rational strain design. In addition, we are able to draw some important conclusions regarding the underlying metabolic mechanisms for observed behaviors of C. thermocellum

Comparison of transcriptional profiles of Clostridium thermocellum grown on cellobiose and pretreated yellow poplar using RNA-Seq

Directory of Open Access Journals (Sweden)

Hui eWei

2014-04-01

Full Text Available The anaerobic, thermophilic bacterium, Clostridium thermocellum, secretes multi-protein enzyme complexes, termed cellulosomes, which synergistically interact with the microbial cell surface and efficiently disassemble plant cell wall biomass. C. thermocellum has also been considered a potential consolidated bioprocessing (CBP organism due to its ability to produce the biofuel products, hydrogen and ethanol. We found that C. thermocellum fermentation of pretreated yellow poplar (PYP produced 30% and 39% of ethanol and hydrogen product concentrations, respectively, compared to fermentation of cellobiose. RNA-seq was used to analyze the transcriptional profiles of these cells. The PYP-grown cells taken for analysis at the late stationary phase showed 1211 genes up-regulated and 314 down-regulated by more than 2-fold compared to the cellobiose-grown cells. These affected genes cover a broad spectrum of specific functional categories. The transcriptional analysis was further validated by sub-proteomics data taken from the literature; as well as by quantitative reverse transcription-PCR (qRT-PCR analyses of selected genes. Specifically, 47 cellulosomal protein-encoding genes, genes for 4 pairs of SigI-RsgI for polysaccharide sensing, 7 cellodextrin ABC transporter genes, and a set of NAD(PH hydogenase and alcohol dehydrogenase genes were up-regulated for cells growing on PYP compared to cellobiose. These genes could be potential candidates for future studies aimed at gaining insight into the regulatory mechanism of this organism as well as for improvement of C. thermocellum in its role as a CBP organism.

Biogeochemical evidence that thermophilic Archaea mediate the anaerobic oxidation of methane

NARCIS (Netherlands)

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

2003-01-01

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

Clostridium difficile infection: molecular pathogenesis and novel therapeutics

Science.gov (United States)

Rineh, Ardeshir; Kelso, Michael J; Vatansever, Fatma; Tegos, George P; Hamblin, Michael R

2015-01-01

The Gram-positive anaerobic bacterium Clostridium difficile produces toxins A and B, which can cause a spectrum of diseases from pseudomembranous colitis to C. difficile-associated diarrhea. A limited number of C. difficile strains also produce a binary toxin that exhibits ADP ribosyltransferase activity. Here, the structure and the mechanism of action of these toxins as well as their role in disease are reviewed. Nosocomial C. difficile infection is often contracted in hospital when patients treated with antibiotics suffer a disturbance in normal gut microflora. C. difficile spores can persist on dry, inanimate surface for months. Metronidazole and oral vancomycin are clinically used for treatment of C. difficile infection but clinical failure and concern about promotion of resistance are motivating the search for novel non-antibiotic therapeutics. Methods for controlling both toxins and spores, replacing gut microflora by probiotics or fecal transplant, and killing bacteria in the anaerobic gut by photodynamic therapy are discussed. PMID:24410618

Anaerobic degradation of landfill leachate using an upflow anaerobic fixed-bed reactor with microbial sulfate reduction

International Nuclear Information System (INIS)

Ben Dhia Thabet, Olfa; Bouallagui, Hassib; Cayol, Jean-luc; Ollivier, Bernard; Fardeau, Marie-Laure; Hamdi, Moktar

2009-01-01

This study evaluated the anaerobic degradation of landfill leachate and sulfate reduction as a function of COD/(SO 4 2- ) ratio in an upflow anaerobic fixed-bed reactor. The reactor, which was inoculated with a mixed consortium, was operated under a constant hydraulic retention time (HRT) of 5 days. We investigated the effect of COD/(SO 4 2- ) ratio variation on the sulfate reduction efficiency, hydrogen sulfide production, chemical oxygen demand (COD) removal, conductivity, and pH variation. The best reactor performance, with significant sulfate reduction efficiency and COD removal efficiency of 91% and 87%, respectively, was reached under a COD/(SO 4 2- ) ratio of 1.17. Under these conditions, microscopic analysis showed the abundance of vibrios and rod-shaped bacterial cells. Two anaerobic bacteria were isolated from the reactor sludge. Phylogenetic studies performed on these strains identified strain A1 as affiliated to Clostridium genus and strain H1 as a new species of sulfate-reducing bacteria affiliated to the Desulfovibrio genus. The closest phylogenetic relative of strain H1 was Desulfovibrio desulfuricans, at 96% similarity for partial 16S RNA gene sequence data. Physiological and metabolic characterization was performed for this strain.

Proposal to restrict the genus Clostridium Prazmowski to Clostridium butyricum and related species.

Science.gov (United States)

Lawson, Paul A; Rainey, Fred A

2016-02-01

The genus Clostridium as presently constituted is phylogenetically and phenotypically incoherent. Data from polyphasic taxonomic studies indicate that the genus comprises a collection of very heterogeneous species. Numerous phylogenetic studies, principally based on sequencing of the 16S rRNA gene, indicate that the genus Clostridium should be restricted to Clostridium cluster I as Clostridium sensu stricto . Despite these findings, authors continue to add novel species to the genus Clostridium that do not fall within the radiation of cluster I and the type species Clostridium butyricum , thus perpetuating the confusion associated with the taxonomy of this group. Here, we formally propose that members of the genus Clostridium Prazmowski be restricted to the type species C. butyricum and cluster I species. Eubacterium moniliforme , Eubacterium tarantellae , Sarcina maxima and Sarcina ventriculi should be transferred to the genus Clostridium as Clostridium moniliforme comb. nov., Clostridium tarantellae comb. nov., Clostridium maximum comb. nov. and Clostridium ventriculi comb. nov. A novel genus, Hathewaya gen. nov., is proposed for the species Clostridium histolyticum , Clostridium limosum and Clostridium proteolyticum as Hathewaya histolytica gen. nov. comb. nov., Hathewaya limosa comb. nov. and Hathewaya proteolytica comb. nov. The type species of the genus Hathewaya is Hathewaya histolytica.

Evaluation of the in vitro activity of levornidazole, its metabolites and comparators against clinical anaerobic bacteria.

Science.gov (United States)

Hu, Jiali; Zhang, Jing; Wu, Shi; Zhu, Demei; Huang, Haihui; Chen, Yuancheng; Yang, Yang; Zhang, Yingyuan

2014-12-01

This study evaluated the in vitro anti-anaerobic activity and spectrum of levornidazole, its metabolites and comparators against 375 clinical isolates of anaerobic bacteria, including Gram-negative bacilli (181 strains), Gram-negative cocci (11 strains), Gram-positive bacilli (139 strains) and Gram-positive cocci (44 strains), covering 34 species. Minimum inhibitory concentrations (MICs) of levornidazole, its five metabolites and three comparators against these anaerobic isolates were determined by the agar dilution method. Minimum bactericidal concentrations (MBCs) of levornidazole and metronidazole were measured against 22 strains of Bacteroides fragilis. Levornidazole showed good activity against B. fragilis, other Bacteroides spp., Clostridium difficile, Clostridium perfringens and Peptostreptococcus magnus, evidenced by MIC90 values of 0.5, 1, 0.25, 2 and 1mg/L, respectively. The activity of levornidazole and the comparators was poor for Veillonella spp. Generally, levornidazole displayed activity similar to or slightly higher than that of metronidazole, ornidazole and dextrornidazole against anaerobic Gram-negative bacilli, Gram-positive bacilli and Gram-positive cocci, especially B. fragilis. Favourable anti-anaerobic activity was also seen with levornidazole metabolites M1 and M4 but not M2, M3 or M5. For the 22 clinical B. fragilis strains, MBC50 and MBC90 values of levornidazole were 2mg/L and 4mg/L, respectively. Both MBC50/MIC50 and MBC90/MIC90 ratios of levornidazole were 4, similar to those of metronidazole. Levornidazole is an important anti-anaerobic option in clinical settings in terms of its potent and broad-spectrum in vitro activity, bactericidal property, and the anti-anaerobic activity of its metabolites M1 and M4. Copyright © 2014 Elsevier B.V. and the International Society of Chemotherapy. All rights reserved.

Expression of a Clostridium perfringens genome-encoded putative N-acetylmuramoyl-L-alanine amidase as a potential antimicrobial to control the bacterium

Science.gov (United States)

Clostridium perfringens is a Gram-positive, spore-forming anaerobic bacterium that plays a substantial role in non-foodborne human, animal and avian diseases as well as human foodborne disease. Previously discovered C. perfringens bacteriophage lytic enzyme amino acid sequences were utilized to iden...

Genus-Wide Assessment of Lignocellulose Utilization in the Extremely Thermophilic Genus Caldicellulosiruptor by Genomic, Pangenomic, and Metagenomic Analyses.

Science.gov (United States)

Lee, Laura L; Blumer-Schuette, Sara E; Izquierdo, Javier A; Zurawski, Jeffrey V; Loder, Andrew J; Conway, Jonathan M; Elkins, James G; Podar, Mircea; Clum, Alicia; Jones, Piet C; Piatek, Marek J; Weighill, Deborah A; Jacobson, Daniel A; Adams, Michael W W; Kelly, Robert M

2018-05-01

Metagenomic data from Obsidian Pool (Yellowstone National Park, USA) and 13 genome sequences were used to reassess genus-wide biodiversity for the extremely thermophilic Caldicellulosiruptor The updated core genome contains 1,401 ortholog groups (average genome size for 13 species = 2,516 genes). The pangenome, which remains open with a revised total of 3,493 ortholog groups, encodes a variety of multidomain glycoside hydrolases (GHs). These include three cellulases with GH48 domains that are colocated in the glucan degradation locus (GDL) and are specific determinants for microcrystalline cellulose utilization. Three recently sequenced species, Caldicellulosiruptor sp. strain Rt8.B8 (renamed here Caldicellulosiruptor morganii ), Thermoanaerobacter cellulolyticus strain NA10 (renamed here Caldicellulosiruptor naganoensis ), and Caldicellulosiruptor sp. strain Wai35.B1 (renamed here Caldicellulosiruptor danielii ), degraded Avicel and lignocellulose (switchgrass). C. morganii was more efficient than Caldicellulosiruptor bescii in this regard and differed from the other 12 species examined, both based on genome content and organization and in the specific domain features of conserved GHs. Metagenomic analysis of lignocellulose-enriched samples from Obsidian Pool revealed limited new information on genus biodiversity. Enrichments yielded genomic signatures closely related to that of Caldicellulosiruptor obsidiansis , but there was also evidence for other thermophilic fermentative anaerobes ( Caldanaerobacter , Fervidobacterium , Caloramator , and Clostridium ). One enrichment, containing 89.8% Caldicellulosiruptor and 9.7% Caloramator , had a capacity for switchgrass solubilization comparable to that of C. bescii These results refine the known biodiversity of Caldicellulosiruptor and indicate that microcrystalline cellulose degradation at temperatures above 70°C, based on current information, is limited to certain members of this genus that produce GH48 domain

Anaerobic digestion of sulfate-acidified cattle slurry: One-stage vs. two-stage.

Science.gov (United States)

Moset, Veronica; Ottosen, Lars Ditlev Mørck; Xavier, Cristiane de Almeida Neves; Møller, Henrik Bjarne

2016-05-15

Two strategies to include acidified cattle manure (AcCM) in co-digestion with normal cattle manure (CM) are presented in this work. The strategies are a single thermophilic (50 °C) continuous stirred tank reactor (CSTR) anaerobic digestion and a two-step (65 °C + 50 °C) CSTR process. In both strategies, two different inclusion levels of H2SO4-acidified CM (10% and 20%) in co-digestion with normal CM were tested and compared with a control CSTR fed only CM. Important enhancement of methane (CH4) yield and solid reductions were observed in the thermophilic one-step CSTR working with 10% AcCM. However, a higher inclusion level of AcCM (20%) caused volatile fatty acid accumulation in the reactor and a more than 30% reduction in CH4 production. In terms of CH4 production, when 10% of AcCM was co-digested with 90% of CM, the two-step anaerobic co-digestion yielded less than the single step. During the first step of the two-step CSTR process, acidogenesis and a partial sulfate reduction were achieved. However, sulfide stripping between the first and the second step must be promoted in order to advance this technology. Copyright © 2016 Elsevier Ltd. All rights reserved.

Thermophilic Biohydrogen Production

DEFF Research Database (Denmark)

Karakashev, Dimitar Borisov; Angelidaki, Irini

2011-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2002-07-01

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

Metagenomic analysis on thermophilic biogas reactors fed with high load of Long Chain Fatty Acids (LCFA)

DEFF Research Database (Denmark)

Zhu, Xinyu; De Francisci, Davide; Treu, Laura

In anaerobic digestion systems, the accumulation of long chain fatty acids (LCFA) leads to process instability and decrease of the methane production. This detrimental condition is known to be reversible depending on the concentration of the accumulated LCFAs and mainly on the microbial consortium...... due to LCFA increase in the feedstock composition. The result shows that the addition of sodium oleate caused a reversible inhibition of reactor. The correlation between the microbial community’s profile and the reactors performance indicated that Syntrophomonas was the genus most likely involved...... in sodium oleate degradation. Other genera that were found abundant are Pseudomonas, Clostridium XI and Clostridium III. The relative abundance of these genera was not significantly affected by the addition of sodium oleate, and this indicates that they are probably involved in later steps of degradation...

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

Energy Technology Data Exchange (ETDEWEB)

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

1993-08-31

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

The cellulase activity of an extreme thermophile

Energy Technology Data Exchange (ETDEWEB)

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

1991-05-01

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

Methanogenesis in Thermophilic Biogas Reactors

DEFF Research Database (Denmark)

Ahring, Birgitte Kiær

1995-01-01

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

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

DEFF Research Database (Denmark)

Angelidaki, Irini; Ahring, Birgitte Kiær

1995-01-01

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

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

Science.gov (United States)

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

2016-12-01

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

Diversity of bacteria and glycosyl hydrolase family 48 genes in cellulolytic consortia enriched from thermophilic biocompost.

Science.gov (United States)

Izquierdo, Javier A; Sizova, Maria V; Lynd, Lee R

2010-06-01

The enrichment from nature of novel microbial communities with high cellulolytic activity is useful in the identification of novel organisms and novel functions that enhance the fundamental understanding of microbial cellulose degradation. In this work we identify predominant organisms in three cellulolytic enrichment cultures with thermophilic compost as an inoculum. Community structure based on 16S rRNA gene clone libraries featured extensive representation of clostridia from cluster III, with minor representation of clostridial clusters I and XIV and a novel Lutispora species cluster. Our studies reveal different levels of 16S rRNA gene diversity, ranging from 3 to 18 operational taxonomic units (OTUs), as well as variability in community membership across the three enrichment cultures. By comparison, glycosyl hydrolase family 48 (GHF48) diversity analyses revealed a narrower breadth of novel clostridial genes associated with cultured and uncultured cellulose degraders. The novel GHF48 genes identified in this study were related to the novel clostridia Clostridium straminisolvens and Clostridium clariflavum, with one cluster sharing as little as 73% sequence similarity with the closest known relative. In all, 14 new GHF48 gene sequences were added to the known diversity of 35 genes from cultured species.

Thermoanaerobacter mathranii sp. nov., an ethanol-producing, extremely thermophilic anaerobic bacterium from a hot spring in Iceland

DEFF Research Database (Denmark)

Larsen, L.; Nielsen, P.; Ahring, B.K.

1997-01-01

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

Effects of gamma ray and electron-beam irradiations on survival of anaerobic and facultatively anaerobic bacteria

International Nuclear Information System (INIS)

Miyahara, Michiko; Miyahara, Makoto

2002-01-01

An extension of the approval for food irradiation is desired due to the increase in the incidence of food poisoning in the world. One anaerobic (Clostridium perfringens) and four facultatively anaerobic (Bacillus cereus, Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Enteritidis) bacteria irradiated with gamma ray or electron beam (E-beam) were tested in terms of survival on agar under packaging atmosphere. Using pouch pack, effects of two irradiations on survival of anaerobic and facultatively anaerobic bacteria were evaluated comparatively. E-beam irradiation was more effective than gamma ray irradiation in decreasing the lethal dose 10% (D 10 ) value of B. cereus at 4 deg C, slightly more effective in that of E. coli O157, and similarly effective in that of the other three bacteria at 4 deg C. The gamma irradiation of the bacteria without incubation at 4 deg C before irradiation was more effective than that of the bacteria with incubation overnight at 4 deg C before irradiation in decreasing the D10 values of these bacteria (B. cereus, E. coli O157, and L. monocytogenes). Furthermore, ground beef patties inoculated with bacteria were irradiated with 1 kGy by E-beam (5 MeV) at 4 deg C. The inoculated bacteria in the 1-9 mm beef patties were killed by 1 kGy E-beam irradiation and some bacteria in more than 9 mm beef patties were not killed by the irradiation. (author)

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

Science.gov (United States)

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

2009-04-15

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

Degradation of cellulosic biomass and its subsequent utilization for the production of chemical feedstocks. Progress report, December 1, 1976--February 28, 1977

Energy Technology Data Exchange (ETDEWEB)

Wang, D.I.C.; Cooney, C.L.; Demain, A.L.; Gomez, R.F.; Sinskey, A.J.

1977-05-01

The microbial degradation of cellulosic biomass has focused on the use of a thermophilic (55 to 60/sup 0/C), anaerobic microorganism, Clostridium thermocellum. When this organism is grown with a crystalline cellulose, the cellulases produced are mainly extracellular. This same organism when grown on solka floc, high specific growth rates are exhibited as well as the ability to produce high concentrations of soluble reducing sugars. The rate of soluble sugar production appears to be growth associated. Studies on acrylic acid production are focused on two organisms: Peptostreptococcus elsdenii and Clostridium propionicum. An economic analysis on the acetone/butanol fermentation has been completed. The results show that continuous operation can reduce significantly the production cost compared to batch operation with the cost of raw material being major fractions for both processes. An increase in solvent concentration will effect substantial cost reduction. The production of acetic acid by Clostridium thermoaceticum has been shown to occur rapidly by this organism. Acetic acid concentration between 15 to 20 gm/liter have been achieved, corresponding to 86 percent of the theoretical maximum yield.

Isolation of Clostridium difficile and Detection of A and B Toxins Encoding Genes

OpenAIRE

Abbas Ali Imani Fooladi; Sadegh Rahmati; Jalil Falah Mehr Abadi; Raheleh Halabian; Hamid Sedighian; Mohammad Javad Soltanpour; Mohsen Rahimi

2014-01-01

Background: Clostridium difficile is the most important anaerobic, gram positive, spore forming bacillus which is known as a prevalent factor leading to antibiotic associated diarrheas and is the causative agent of pseudomembrane colitis. The role of this bacterium along with the over use of antibiotics have been proved to result in colitis. The major virulence factors of these bacteria are the A and B toxins. Objectives: The purpose of this study was to isolate C. difficile from sto...

A novel regulator controls Clostridium difficile sporulation, motility and toxin production.

Science.gov (United States)

Edwards, Adrianne N; Tamayo, Rita; McBride, Shonna M

2016-06-01

Clostridium difficile is an anaerobic pathogen that forms spores which promote survival in the environment and transmission to new hosts. The regulatory pathways by which C. difficile initiates spore formation are poorly understood. We identified two factors with limited similarity to the Rap sporulation proteins of other spore-forming bacteria. In this study, we show that disruption of the gene CD3668 reduces sporulation and increases toxin production and motility. This mutant was more virulent and exhibited increased toxin gene expression in the hamster model of infection. Based on these phenotypes, we have renamed this locus rstA, for regulator of sporulation and toxins. Our data demonstrate that RstA is a bifunctional protein that upregulates sporulation through an unidentified pathway and represses motility and toxin production by influencing sigD transcription. Conserved RstA orthologs are present in other pathogenic and industrial Clostridium species and may represent a key regulatory protein controlling clostridial sporulation. © 2016 John Wiley & Sons Ltd.

Initiation of sporulation in Clostridium difficile: a twist on the classic model.

Science.gov (United States)

Edwards, Adrianne N; McBride, Shonna M

2014-09-01

The formation of dormant endospores is a complex morphological process that permits long-term survival in inhospitable environments for many Gram-positive bacteria. Sporulation for the anaerobic gastrointestinal pathogen Clostridium difficile is necessary for survival outside of the gastrointestinal tract of its host. While the developmental stages of spore formation are largely conserved among endospore-forming bacteria, the genus Clostridium appears to be missing a number of conserved regulators required for efficient sporulation in other spore-forming bacteria. Several recent studies have discovered novel mechanisms and distinct regulatory pathways that control the initiation of sporulation and early-sporulation-specific gene expression. These differences in regulating the decision to undergo sporulation reflects the unique ecological niche and environmental conditions that C. difficile inhabits and encounters within the mammalian host. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Epidemiology and antimicrobial susceptibilities of wound isolates of obligate anaerobes from combat casualties.

Science.gov (United States)

White, Brian K; Mende, Katrin; Weintrob, Amy C; Beckius, Miriam L; Zera, Wendy C; Lu, Dan; Bradley, William; Tribble, David R; Schnaubelt, Elizabeth R; Murray, Clinton K

2016-02-01

Data from recent conflicts related to war wounds and obligate anaerobes are limited. We define the epidemiology and antimicrobial susceptibility of obligate anaerobes from Iraq and Afghanistan casualties (6/2009-12/2013), as well as their association with clinical outcomes. Susceptibility against eleven antibiotics (7 classes) was tested. Overall, 59 patients had 119 obligate anaerobes identified (83 were first isolates). Obligate anaerobes were isolated 7-13 days post-injury, primarily from lower extremity wounds (43%), and were largely Bacteroides spp. (42%) and Clostridium spp. (19%). Patients with pelvic wounds were more likely to have Bacteroides spp. and concomitant resistant gram-negative aerobes. Seventy-three percent of isolates were resistant to ≥1 antimicrobials. Bacteroides spp. demonstrated the most resistance (16% of first isolates). Patients with resistant isolates had similar outcomes to those with susceptible strains. Serial recovery of isolates occurred in 15% of patients and was significantly associated with isolation of Bacteroides spp., along with resistant gram-negative aerobes. Published by Elsevier Inc.

Anaerobes as Sources of Bioactive Compounds and Health Promoting Tools.

Science.gov (United States)

Mamo, Gashaw

Aerobic microorganisms have been sources of medicinal agents for several decades and an impressive variety of drugs have been isolated from their cultures, studied and formulated to treat or prevent diseases. On the other hand, anaerobes, which are believed to be the oldest life forms on earth and evolved remarkably diverse physiological functions, have largely been neglected as sources of bioactive compounds. However, results obtained from the limited research done so far show that anaerobes are capable of producing a range of interesting bioactive compounds that can promote human health. In fact, some of these bioactive compounds are found to be novel in their structure and/or mode of action.Anaerobes play health-promoting roles through their bioactive products as well as application of whole cells. The bioactive compounds produced by these microorganisms include antimicrobial agents and substances such as immunomodulators and vitamins. Bacteriocins produced by anaerobes have been in use as preservatives for about 40 years. Because these substances are effective at low concentrations, encounter relatively less resistance from bacteria and are safe to use, there is a growing interest in these antimicrobial agents. Moreover, several antibiotics have been reported from the cultures of anaerobes. Closthioamide and andrimid produced by Clostridium cellulolyticum and Pantoea agglomerans, respectively, are examples of novel antibiotics of anaerobe origin. The discovery of such novel bioactive compounds is expected to encourage further studies which can potentially lead to tapping of the antibiotic production potential of this fascinating group of microorganisms.Anaerobes are widely used in preparation of fermented foods and beverages. During the fermentation processes, these organisms produce a number of bioactive compounds including anticancer, antihypertensive and antioxidant substances. The well-known health promoting effect of fermented food is mostly due to these

An in Vitro Experimental Study on the Antimicrobial Activity of Silicone Oil against Anaerobic Bacteria.

Science.gov (United States)

Arici, Ceyhun; Aras, Cengiz; Tokman, Hrisi Bahar; Torun, Muzeyyen Mamal

2016-01-01

To investigate the in vitro antimicrobial activity of silicone oil against anaerobic agents, specifically Propionibacterium acnes, Peptostreptococcus spp., Peptostreptococcus anaerobius, Bacteroides fragilis, Fuobacterium spp., and Clostridium tertium. A 0.5 McFarland turbidity of Propionibacterium acnes, Peptostreptococcus spp., Peptostreptococcus anaerobius, Bacteroides fragilis, Fuobacterium spp., and Clostridium tertium was prepared, and 0.1 mL was inoculated into 0.9 mL of silicone oil. Control inoculations were performed in anaerobic blood agar and fluid thioglycollate medium without silicone oil. Propionibacterium acnes retained their viability on the 3rd day in the presence of silicone oil. In total, 9.7 × 10(6) colonies were enumerated from 1 mL of silicone oil. After a prolonged incubation of 7 days, the number of colonies observed was 9.2 × 10(6). The other bacteria disappeared after the 3rd day of incubation in silicone oil. Propionibacterium acnes, which is the most common chronic postoperative endophthalmitis agent, is thought to be resistant to silicone oil.

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

NARCIS (Netherlands)

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

2005-01-01

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

Isolation of obligate anaerobic bacteria from ulcerative keratitis in domestic animals.

Science.gov (United States)

Ledbetter, Eric C; Scarlett, Janet M

2008-01-01

To determine the frequency of obligate anaerobic bacterial isolation from corneal samples of domestic animals with ulcerative keratitis and to characterize the historical, clinical, cytological, and microbiological features of culture-positive cases. Three hundred and thirty domestic animals with ulcerative keratitis. Anaerobic bacteriologic culture and Gram stain were performed on corneal samples from consecutive animals examined with suspect septic ulcerative keratitis. Additional corneal diagnostics included: aerobic bacteriologic culture for all species; fungal culture for ungulates; Mycoplasma culture and virus isolation or feline herpesvirus-1 (FHV-1) polymerase chain reaction (PCR) for cats. Historical, clinical, and cytological findings were correlated with microbiologic data. Anaerobic bacteria were isolated from 13.0% of corneal samples (dogs: 14.0%; horses: 12.9%; cats: 7.9%; alpacas: 18.8%). The most frequent isolates were Clostridium, Peptostreptococcus, Actinomyces, Fusobacterium, and Bacteroides species. The majority of these infections were mixed anaerobic and aerobic bacteria, unless antimicrobial therapy had been administered prior to presentation. The clinical appearance of anaerobic bacterial culture-positive cases was highly variable. Ocular trauma, pre-existing corneal disease, previous corneal surgery, and chronic dermatological disease were significantly (P anaerobic cultures in one or more species. The results of the present study demonstrate that obligate anaerobic bacteria are present within the intralesional flora of ulcerative keratitis in domestic animals. In most species evaluated, these bacteria were identified infrequently. Anaerobic bacterial infection of the cornea most frequently occurs in association with other ocular pathogens and previous corneal abnormalities.

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

Science.gov (United States)

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

2014-11-01

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

In vitro activity of cefbuperazone, a new cephamycin, against anaerobic bacteria.

OpenAIRE

Prabhala, R H; Thadepalli, H; Rao, B; Bansal, M B; Marshall, R

1985-01-01

The 90% MIC of cefbuperazone (BMY 25182) was 32 micrograms/ml for Bacteroides fragilis and Bacteroides spp., 128 micrograms/ml for Fusobacterium and Clostridium spp., 64 micrograms/ml for Eubacterium and Peptococcus spp., 8 micrograms/ml for Actinomyces spp., and 32 micrograms/ml for Peptostreptococcus spp. The level of activity of cefbuperazone was higher against B. fragilis and lower against anaerobic cocci than those of related cephalosporins, i.e., cefoxitin, cefoperazone, cefotaxime, cef...

MALDI-TOF MS identification of anaerobic bacteria: assessment of pre-analytical variables and specimen preparation techniques.

Science.gov (United States)

Hsu, Yen-Michael S; Burnham, Carey-Ann D

2014-06-01

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has emerged as a tool for identifying clinically relevant anaerobes. We evaluated the analytical performance characteristics of the Bruker Microflex with Biotyper 3.0 software system for identification of anaerobes and examined the impact of direct formic acid (FA) treatment and other pre-analytical factors on MALDI-TOF MS performance. A collection of 101 anaerobic bacteria were evaluated, including Clostridium spp., Propionibacterium spp., Fusobacterium spp., Bacteroides spp., and other anaerobic bacterial of clinical relevance. The results of our study indicate that an on-target extraction with 100% FA improves the rate of accurate identification without introducing misidentification (Panaerobes grown in suboptimal conditions, such as on selective culture media and following oxygen exposure. In conclusion, we report on a number of simple and cost-effective pre- and post-analytical modifications could enhance MALDI-TOF MS identification for anaerobic bacteria. Copyright © 2014 Elsevier Inc. All rights reserved.

Stress hormone epinephrine (adrenaline) and norepinephrine (noradrenaline) effects on the anaerobic bacteria.

Science.gov (United States)

Boyanova, Lyudmila

2017-04-01

Microbial endocrinology is a relatively new research area that already encompasses the anaerobes. Stress hormones, epinephrine and norepinephrine, can affect the growth of anaerobic bacteria such as Fusobacterium nucleatum, Prevotella spp., Porhyromonas spp., Tanerella forsythia and Propionibacterium acnes and can increase virulence gene expression, iron acquisition and many virulence factors of some anaerobic species such as Clostridium perfringens, Porphyromonas gingivalis and Brachyspira pilosicoli. Epinephrine and norepinephrine effects can lead to a growth increase or decrease, or no effect on the growth of the anaerobes. The effects are species-specific and perhaps strain-specific. Discrepancies in the results of some studies can be due to the different methods and media used, catecholamine concentrations, measurement techniques and the low number of strains tested. Biological effects of the stress hormones on the anaerobes may range from halitosis and a worsening of periodontal diseases to tissue damages and atherosclerotic plaque ruptures. Optimizations of the research methods and a detailed assessment of the catecholamine effects in conditions mimicking those in affected organs and tissues, as well as the effects on the quorum sensing and virulence of the anaerobes and the full spectrum of biological consequences of the effects are interesting topics for further evaluation. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

2016-11-01

Proof of principle of biohythane and potential energy production from garden waste (GW) is demonstrated in this study in a two-step process coupling dark fermentation and anaerobic digestion. The synergistic effect of using co-cultures of extreme thermophiles to intensify biohydrogen dark fermentation is demonstrated using xylose, cellobiose and GW. Co-culture of Caldicellulosiruptor saccharolyticus and Thermotoga maritima showed higher hydrogen production yields from xylose (2.7±0.1molmol(-1) total sugar) and cellobiose (4.8±0.3molmol(-1) total sugar) compared to individual cultures. Co-culture of extreme thermophiles C. saccharolyticus and Caldicellulosiruptor bescii increased synergistically the hydrogen production yield from GW (98.3±6.9Lkg(-1) (VS)) compared to individual cultures and co-culture of T. maritima and C. saccharolyticus. The biochemical methane potential of the fermentation end-products was 322±10Lkg(-1) (CODt). Biohythane, a biogas enriched with 15% hydrogen could be obtained from GW, yielding a potential energy generation of 22.2MJkg(-1) (VS). Copyright © 2016 Elsevier Ltd. All rights reserved.

Increased activity of a new chlorofluoroquinolone, BAY y 3118, compared with activities of ciprofloxacin, sparfloxacin, and other antimicrobial agents against anaerobic bacteria.

OpenAIRE

Aldridge, K E

1994-01-01

A total of 435 clinical isolates of anaerobes were tested with a broth microdilution method to determine the activity of BAY y 3118 compared with those of other agents against anaerobic bacteria. All strains of Bacteroides capillosus, Prevotella spp., Porphyromonas spp., Fusobacterium spp., Clostridium spp., Eubacterium spp., Peptostreptococcus spp., and Veillonella parvula were susceptible (MICs of < or = 2 micrograms/ml) to BAY y 3118. Against the 315 strains of the Bacteroides fragilis gro...

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

DEFF Research Database (Denmark)

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

2008-01-01

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

ENDOSPORES OF THERMOPHILIC FERMENTATIVE BACTERIA

DEFF Research Database (Denmark)

Volpi, Marta

2016-01-01

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

Biocorrosive Thermophilic Microbial Communities in Alaskan North Slope Oil Facilities

Energy Technology Data Exchange (ETDEWEB)

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

2009-09-16

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

Inactivation of a bovine enterovirus and a bovine parvovirus in cattle manure by anaerobic digestion, heat treatment, gamma irradiation, ensilage and composting

Energy Technology Data Exchange (ETDEWEB)

Monteith, H.D.; Shannon, E.E.; Derbyshire, J.B.

1986-08-01

A bovine enterovirus and a bovine parvovirus seeded into liquid cattle manure were rapidly inactivated by anaerobic digestion under thermophilic conditions (55/sup 0/C), but the same viruses survived for up to 13 and 8 days respectively under mesophilic conditions (35/sup 0/C). The enterovirus was inactivated in digested liquid manure heated to 70/sup 0/C for 30 min, but the parvovirus was not inactivated by this treatment. The enterovirus, seeded into single cell protein (the solids recovered by centrifugation of digested liquid manure), was inactivated by a gamma irradiation dose of 1.0 Mrad, but the parvovirus survived this dose. When single cell protein seeded with bovine enterovirus or bovine parvovirus was ensiled with cracked corn, the enterovirus was inactivated after a period of 30 days, while the parvovirus survived for 30 days in one of two experiments. Neither the enterovirus nor the parvovirus survived composting for 28 days in a thermophilic aerobic environment when seeded into the solid fraction of cattle manure. It was concluded that, of the procedures tested, only anaerobic digestion under thermophilic conditions appeared to be reliable method of viral inactivation to ensure the safety of single cell protein for refeeding to livestock. Composting appeared to be a suitable method for the disinfection of manure for use as a soil conditioner.

Increasing the thermal stability of cellulase C using rules learned from thermophilic proteins: a pilot study.

Science.gov (United States)

Németh, Attila; Kamondi, Szilárd; Szilágyi, András; Magyar, Csaba; Kovári, Zoltán; Závodszky, Péter

2002-05-02

Some structural features underlying the increased thermostability of enzymes from thermophilic organisms relative to their homologues from mesophiles are known from earlier studies. We used cellulase C from Clostridium thermocellum to test whether thermostability can be increased by mutations designed using rules learned from thermophilic proteins. Cellulase C has a TIM barrel fold with an additional helical subdomain. We designed and produced a number of mutants with the aim to increase its thermostability. Five mutants were designed to create new electrostatic interactions. They all retained catalytic activity but exhibited decreased thermostability relative to the wild-type enzyme. Here, the stabilizing contributions are obviously smaller than the destabilization caused by the introduction of the new side chains. In another mutant, the small helical subdomain was deleted. This mutant lost activity but its melting point was only 3 degrees C lower than that of the wild-type enzyme, which suggests that the subdomain is an independent folding unit and is important for catalytic function. A double mutant was designed to introduce a new disulfide bridge into the enzyme. This mutant is active and has an increased stability (deltaT(m)=3 degrees C, delta(deltaG(u))=1.73 kcal/mol) relative to the wild-type enzyme. Reduction of the disulfide bridge results in destabilization and an altered thermal denaturation behavior. We conclude that rules learned from thermophilic proteins cannot be used in a straightforward way to increase the thermostability of a protein. Creating a crosslink such as a disulfide bond is a relatively sure-fire method but the stabilization may be smaller than calculated due to coupled destabilizing effects.

Clinical features and prognostic factors of anaerobic infections: a 7-year retrospective study.

Science.gov (United States)

Park, Yoonseon; Choi, Jun Young; Yong, Dongeun; Lee, Kyungwon; Kim, June Myung

2009-03-01

Risk factors for mortality resulting from anaerobic infection are incompletely defined. The clinical significance of a broad range of pathogenic obligate anaerobic organisms was examined, and factors independently associated with mortality were identified in patients with clinically significant anaerobic infections. The medical records of 1,050 patients with anaerobic infections were retrospectively reviewed at Severance Hospital in Seoul, Korea. The mean age of the patients was 54.1+/-16.8 years, and 57.7% were men. Overall, 320 (30.5%) patients with case-defined illness experienced pain at the affected site, and 230 (21.9%) experienced pus flow from lesions. Ten (1.4%) patients presented with shock, and 80.3% of the clinically significant cases were polymicrobial anaerobic infections. The mean number of pathogens, including aerobic and anaerobic bacteria, was 3.7+/-1.0 (minimum 1, maximum 5), and the number of anaerobic organisms was 1.0+/-0.3 in each specimen. The major pathogens by rank were the Bacteroides fragilis group, which accounted for 41.8% of anaerobic infections, followed by Clostridium spp. (11.8%), Prevotella spp. (9.4%), and Peptostreptococcus spp. (8.4%). Escherichia coli (17.5%), Staphylococcus aureus (7.5%), and Klebsiella pneumoniae (7.5%) were common concomitant aerobic organisms. The overall crude mortality rate resulting from anaerobic infection was 29.7%. Among the determining factors associated with mortality, liver disease (p=0.003) and old age (p=0.005) were significant in multivariate analysis. Anaerobic infection is polymicrobial and has a significant role in morbidity and mortality. Underlying liver disease was associated with poor prognosis in anaerobic infection.

Early Microbial Evolution: The Age of Anaerobes.

Science.gov (United States)

Martin, William F; Sousa, Filipa L

2015-12-18

In this article, the term "early microbial evolution" refers to the phase of biological history from the emergence of life to the diversification of the first microbial lineages. In the modern era (since we knew about archaea), three debates have emerged on the subject that deserve discussion: (1) thermophilic origins versus mesophilic origins, (2) autotrophic origins versus heterotrophic origins, and (3) how do eukaryotes figure into early evolution. Here, we revisit those debates from the standpoint of newer data. We also consider the perhaps more pressing issue that molecular phylogenies need to recover anaerobic lineages at the base of prokaryotic trees, because O2 is a product of biological evolution; hence, the first microbes had to be anaerobes. If molecular phylogenies do not recover anaerobes basal, something is wrong. Among the anaerobes, hydrogen-dependent autotrophs--acetogens and methanogens--look like good candidates for the ancestral state of physiology in the bacteria and archaea, respectively. New trees tend to indicate that eukaryote cytosolic ribosomes branch within their archaeal homologs, not as sisters to them and, furthermore tend to root archaea within the methanogens. These are major changes in the tree of life, and open up new avenues of thought. Geochemical methane synthesis occurs as a spontaneous, abiotic exergonic reaction at hydrothermal vents. The overall similarity between that reaction and biological methanogenesis fits well with the concept of a methanogenic root for archaea and an autotrophic origin of microbial physiology. Copyright © 2016 Cold Spring Harbor Laboratory Press; all rights reserved.

Thermophilic Fungi: Their Physiology and Enzymes†

Science.gov (United States)

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

2000-01-01

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

Genome-centric metatranscriptomes and ecological roles of the active microbial populations during cellulosic biomass anaerobic digestion.

Science.gov (United States)

Jia, Yangyang; Ng, Siu-Kin; Lu, Hongyuan; Cai, Mingwei; Lee, Patrick K H

2018-01-01

Although anaerobic digestion for biogas production is used worldwide in treatment processes to recover energy from carbon-rich waste such as cellulosic biomass, the activities and interactions among the microbial populations that perform anaerobic digestion deserve further investigations, especially at the population genome level. To understand the cellulosic biomass-degrading potentials in two full-scale digesters, this study examined five methanogenic enrichment cultures derived from the digesters that anaerobically digested cellulose or xylan for more than 2 years under 35 or 55 °C conditions. Metagenomics and metatranscriptomics were used to capture the active microbial populations in each enrichment culture and reconstruct their meta-metabolic network and ecological roles. 107 population genomes were reconstructed from the five enrichment cultures using a differential coverage binning approach, of which only a subset was highly transcribed in the metatranscriptomes. Phylogenetic and functional convergence of communities by enrichment condition and phase of fermentation was observed for the highly transcribed populations in the metatranscriptomes. In the 35 °C cultures grown on cellulose, Clostridium cellulolyticum -related and Ruminococcus -related bacteria were identified as major hydrolyzers and primary fermenters in the early growth phase, while Clostridium leptum -related bacteria were major secondary fermenters and potential fatty acid scavengers in the late growth phase. While the meta-metabolism and trophic roles of the cultures were similar, the bacterial populations performing each function were distinct between the enrichment conditions. Overall, a population genome-centric view of the meta-metabolism and functional roles of key active players in anaerobic digestion of cellulosic biomass was obtained. This study represents a major step forward towards understanding the microbial functions and interactions at population genome level during the

Hydrogen Production by Thermophilic Fermentation

NARCIS (Netherlands)

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

2012-01-01

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

Effect of food to microorganism ratio on biohydrogen production from food waste via anaerobic fermentation

Energy Technology Data Exchange (ETDEWEB)

Pan, Jinming [Department of Biosystems Engineering, Zhejiang University, Hangzhou 310029 (China); Department of Biological and Agricultural Engineering, University of California at Davis, One Shields Avenue, Davis, CA 95616 (United States); Zhang, Ruihong; Sun, Huawei [Department of Biological and Agricultural Engineering, University of California at Davis, One Shields Avenue, Davis, CA 95616 (United States); El-Mashad, Hamed M. [Department of Biological and Agricultural Engineering, University of California at Davis, One Shields Avenue, Davis, CA 95616 (United States); Department of Agricultural Engineering, Mansoura University, El-Mansoura (Egypt); Ying, Yibin [Department of Biosystems Engineering, Zhejiang University, Hangzhou 310029 (China)

2008-12-15

The effect of different food to microorganism ratios (F/M) (1-10) on the hydrogen production from the anaerobic batch fermentation of mixed food waste was studied at two temperatures, 35 {+-} 2 C and 50 {+-} 2 C. Anaerobic sludge taken from anaerobic reactors was used as inoculum. It was found that hydrogen was produced mainly during the first 44 h of fermentation. The F/M between 7 and 10 was found to be appropriate for hydrogen production via thermophilic fermentation with the highest yield of 57 ml-H{sub 2}/g VS at an F/M of 7. Under mesophilic conditions, hydrogen was produced at a lower level and in a narrower range of F/Ms, with the highest yield of 39 ml-H{sub 2}/g VS at the F/M of 6. A modified Gompertz equation adequately (R{sup 2} > 0.946) described the cumulative hydrogen production yields. This study provides a novel strategy for controlling the conditions for production of hydrogen from food waste via anaerobic fermentation. (author)

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

Energy Technology Data Exchange (ETDEWEB)

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

1994-01-01

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

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

Science.gov (United States)

Singh, Bijender

2016-01-01

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

Thermophilic microorganisms in biomining.

Science.gov (United States)

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

2016-11-01

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

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

Science.gov (United States)

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

2011-02-01

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

Nitrogen in the Process of Waste Activated Sludge Anaerobic Digestion

Directory of Open Access Journals (Sweden)

Suschka Jan

2014-07-01

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

Alcohol dehydrogenases from thermophilic and hyperthermophilic archaea and bacteria.

Science.gov (United States)

Radianingtyas, Helia; Wright, Phillip C

2003-12-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2012-01-01

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

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

DEFF Research Database (Denmark)

Elsgaard, Lars; Prieur, Daniel

2010-01-01

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

Strong antimicrobial activity of xanthohumol and other derivatives from hops (Humulus lupulus L.) on gut anaerobic bacteria.

Science.gov (United States)

Cermak, Pavel; Olsovska, Jana; Mikyska, Alexandr; Dusek, Martin; Kadleckova, Zuzana; Vanicek, Jiri; Nyc, Otakar; Sigler, Karel; Bostikova, Vanda; Bostik, Pavel

2017-11-01

Anaerobic bacteria, such as Bacteroides fragilis or Clostridium perfringens, are part of indigenous human flora. However, Clostridium difficile represents also an important causative agent of nosocomial infectious antibiotic-associated diarrhoea. Treatment of C. difficile infection is problematic, making it imperative to search for new compounds with antimicrobial properties. Hops (Humulus lupulus L.) contain substances with antibacterial properties. We tested antimicrobial activity of purified hop constituents humulone, lupulone and xanthohumol against anaerobic bacteria. The antimicrobial activity was established against B. fragilis, C. perfringens and C. difficile strains according to standard testing protocols (CLSI, EUCAST), and the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBC) were calculated. All C. difficile strains were toxigenic and clinically relevant, as they were isolated from patients with diarrhoea. Strongest antimicrobial effects were observed with xanthohumol showing MIC and MBC values of 15-107 μg/mL, which are close to those of conventional antibiotics in the strains of bacteria with increased resistance. Slightly higher MIC and MBC values were obtained with lupulone followed by higher values of humulone. Our study, thus, shows a potential of purified hop compounds, especially xanthohumol, as alternatives for treatment of infections caused by select anaerobic bacteria, namely nosocomial diarrhoea caused by resistant strains. © 2017 APMIS. Published by John Wiley & Sons Ltd.

Prevalence of Clostridium botulinum and thermophilic heat-resistant spores in raw carrots and green beans used in French canning industry.

Science.gov (United States)

Sevenier, V; Delannoy, S; André, S; Fach, P; Remize, F

2012-04-16

Two categories of vegetables (carrots and green beans) that are widely used in the manufacture of canned food were surveyed for their spore contamination. Samples were recovered from 10 manufactures spread over all producing areas in France. Two samples over 316 raw vegetables collected were found positive for botulinum neurotoxin producing Clostridia spores as tested by PCR-based GeneDisc assay. Both positive samplestested positive for the type B neurotoxin gene (bont/B). In parallel, heat-resistant spores of thermophilic bacteria that are likely to be associated with canned food spoilage after prolonged incubation at 55 °C were surveyed after specific enrichment. Prevalence varied between 1.6% for Moorella thermoacetica/thermoautotrophica in green bean samples and 8.6% for either Geobacillus stearothermophilus or Thermoanaerobacterium spp. in carrot samples. Vegetable preparation, e.g. washing and edge cutting, considerably reduced spore contamination levels. These data constitute the first wide examination of vegetables specifically cultivated for industrialpurposes for their contamination by spores of thermophilic bacterial species. Copyright © 2012 Elsevier B.V. All rights reserved.

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

Science.gov (United States)

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

2016-06-01

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

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

OpenAIRE

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

2016-01-01

Background This study aims to chemically characterize thin stillage derived from lignocellulosic biomass distillation residues in terms of organic strength, nutrient, and mineral content. The feasibility of performing anaerobic digestion on these stillages at mesophilic (40??C) and thermophilic (55??C) temperatures to produce methane was demonstrated. The microbial communities involved were further characterized. Results Energy and sugar cane stillage have a high chemical oxygen demand (COD o...

Factors controlling pathogen destruction during anaerobic digestion of biowastes

International Nuclear Information System (INIS)

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

2005-01-01

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

Anaerobic digestion of slaughterhouse by-products

International Nuclear Information System (INIS)

Hejnfelt, Anette; Angelidaki, Irini

2009-01-01

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

Anaerobic digestion of slaughterhouse by-products

Energy Technology Data Exchange (ETDEWEB)

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

2009-08-15

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

Comparison of the anaerobic microbiota of deep-water Geodia spp. and sandy sediments in the Straits of Florida.

Science.gov (United States)

Brück, Wolfram M; Brück, Thomas B; Self, William T; Reed, John K; Nitecki, Sonja S; McCarthy, Peter J

2010-05-01

Marine sediments and sponges may show steep variations in redox potential, providing niches for both aerobic and anaerobic microorganisms. Geodia spp. and sediment specimens from the Straits of Florida were fixed using paraformaldehyde and 95% ethanol (v/v) for fluorescence in situ hybridization (FISH). In addition, homogenates of sponge and sediment samples were incubated anaerobically on various cysteine supplemented agars. FISH analysis showed a prominent similarity of microbiota in sediments and Geodia spp. samples. Furthermore, the presence of sulfate-reducing and annamox bacteria as well as other obligate anaerobic microorganisms in both Geodia spp. and sediment samples were also confirmed. Anaerobic cultures obtained from the homogenates allowed the isolation of a variety of facultative anaerobes, primarily Bacillus spp. and Vibrio spp. Obligate anaerobes such as Desulfovibrio spp. and Clostridium spp. were also found. We also provide the first evidence for a culturable marine member of the Chloroflexi, which may enter into symbiotic relationships with deep-water sponges such as Geodia spp. Resuspended sediment particles, may provide a source of microorganisms able to associate or form a symbiotic relationship with sponges.

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

International Nuclear Information System (INIS)

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

2014-01-01

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

MRI-Monitored Intra-Tumoral Injection of Iron-Oxide Labeled Clostridium novyi-NT Anaerobes in Pancreatic Carcinoma Mouse Model

Science.gov (United States)

Zheng, Linfeng; Zhang, Zhuoli; Khazaie, Khashayarsha; Saha, Saurabh; Lewandowski, Robert J.; Zhang, Guixiang; Larson, Andrew C.

2014-01-01

Objectives To validate the feasibility of labeling Clostridium novyi-NT (C.novyi-NT) anaerobes with iron-oxide nanoparticles for magnetic resonance imaging (MRI) and demonstrate the potential to use MRI to visualize intra-tumoral delivery of these iron-oxide labeled C.novyi-NT during percutaneous injection procedures. Materials and Methods All studies were approved by IACUC. C.novyi-NT were labeled with hybrid iron-oxide Texas red nanoparticles. Growth of labeled and control samples were evaluated with optical density. Labeling was confirmed with confocal fluorescence and transmission electron microscopy (TEM). MRI were performed using a 7 Tesla scanner with T2*-weighted (T2*W) sequence. Contrast-to-noise ratio (CNR) measurements were performed for phantoms and signal-to-noise ratio (SNR) measurements performed in C57BL/6 mice (n = 12) with Panc02 xenografts before and after percutaneous injection of iron-oxide labeled C.novyi-NT. MRI was repeated 3 and 7 days post-injection. Hematoxylin-eosin (HE), Prussian blue and Gram staining of tumor specimens were performed for confirmation of intra-tumoral delivery. Results Iron-oxide labeling had no influence upon C.novyi-NT growth. The signal intensity (SI) within T2*W images was significantly decreased for iron-oxide labeled C.novyi-NT phantoms compared to unlabeled controls. Under confocal fluorescence microscopy, the iron-oxide labeled C.novyi-NT exhibited a uniform red fluorescence consistent with observed regions of DAPI staining and overall labeling efficiency was 100% (all DAPI stained C.novyi-NT exhibited red fluorescence). Within TEM images, a large number iron granules were observed within the iron-oxide labeled C.novyi-NT; these were not observed within unlabeled controls. Intra-procedural MRI measurements permitted in vivo visualization of the intra-tumoral distribution of iron-oxide labeled C.novyi-NT following percutaneous injection (depicted as punctate regions of SI reductions within T2*-weighted

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

NARCIS (Netherlands)

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

2004-01-01

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

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

Science.gov (United States)

Ahring, B K; Westermann, P

1987-02-01

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

Anaerobic culture by Total Air Barrier: A preliminary study

Directory of Open Access Journals (Sweden)

Soma Sarkar

2010-03-01

Full Text Available BackgroundFor study with obligate anaerobes, inoculated platescontaining suitable reduced media need handling andincubation under strict anaerobic condition. Instead ofensuring a confined oxygen free chamber for placing seededplates, same purpose may be achieved by creating total airbarrier to the surface.MethodUpper moist surface of freshly prepared anaerobic media inPetri plates were intimately covered with very thintransparent bacteriological inert sterile polyester sheets.Stock culture of Bacteroides fragilis, ATCC 23745 andClostridium sporogenes, ATCC 11437 were grown in cookedmeat broth and then sub-cultured on respective plates, afterlifting the cover sheets. Sheets were again covered andincubated at 37oC ordinary incubator. To performantimicrobial susceptibility test, similarly covered seededplates with well inoculums were inverted en-block afterstripping sides with the help of a spatula. Now antibiotic diskswere placed on upper bare surfaces. After short pre-diffusion,plates were incubated keeping inoculated surface below.Same study was performed by conventional method usingGaspak.ResultsGood growths were noted in both sets of the study;however discrete colonies appeared more flat in nature intest set. Almost identical zones of inhibition were noted inboth sets of sensitivity study. Seven days old growths incovered blood agar plates were found viable when subculturedin cooked meat broths.ConclusionIsolation, identification and susceptibility study for mostclinically important obligate anaerobes may be performedby simple barrier method after appropriatestandardization.

Utilizing thermophilic microbe in lignocelluloses based bioethanol production: Review

Science.gov (United States)

Sriharti, Agustina, Wawan; Ratnawati, Lia; Rahman, Taufik; Salim, Takiyah

2017-01-01

The utilization of thermophilic microbe has attracted many parties, particularly in producing an alternative fuel like ethanol. Bioethanol is one of the alternative energy sources substituting for earth oil in the future. The advantage of using bioethanol is that it can reduce pollution levels and global warming because the result of bioethanol burning doesn't bring in a net addition of CO2 into environment. Moreover, decrease in the reserves of earth oil globally has also contributed to the notion on searching renewable energy resources such as bioethanol. Indonesia has a high biomass potential and can be used as raw material for bioethanol. The utilization of these raw materials will reduce fears of competition foodstuffs for energy production. The enzymes that play a role in degrading lignocelluloses are cellulolytic, hemicellulolytic, and lignolytic in nature. The main enzyme with an important role in bioethanol production is a complex enzyme capable of degrading lignocelluloses. The enzyme can be produced by the thermophilik microbes of the groups of bacteria and fungi such as Trichoderma viride, Clostridium thermocellum, Bacillus sp. Bioethanol production is heavily affected by raw material composition, microorganism type, and the condition of fermentation used.

Biogas production from brewery spent grain enhanced by bioaugmentation with hydrolytic anaerobic bacteria.

Science.gov (United States)

Čater, Maša; Fanedl, Lijana; Malovrh, Špela; Marinšek Logar, Romana

2015-06-01

Lignocellulosic substrates are widely available but not easily applied in biogas production due to their poor anaerobic degradation. The effect of bioaugmentation by anaerobic hydrolytic bacteria on biogas production was determined by the biochemical methane potential assay. Microbial biomass from full scale upflow anaerobic sludge blanket reactor treating brewery wastewater was a source of active microorganisms and brewery spent grain a model lignocellulosic substrate. Ruminococcus flavefaciens 007C, Pseudobutyrivibrio xylanivorans Mz5(T), Fibrobacter succinogenes S85 and Clostridium cellulovorans as pure and mixed cultures were used to enhance the lignocellulose degradation and elevate the biogas production. P. xylanivorans Mz5(T) was the most successful in elevating methane production (+17.8%), followed by the coculture of P. xylanivorans Mz5(T) and F. succinogenes S85 (+6.9%) and the coculture of C. cellulovorans and F. succinogenes S85 (+4.9%). Changes in microbial community structure were detected by fingerprinting techniques. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Isolation of anaerobes during a 30-month observation at a hospital microbiology laboratory].

Science.gov (United States)

Pistono, P G; Rapetti, I; Stacchini, E; Vironda, N; D'Usi, M P; Guasco, C

1989-01-01

The authors evaluate retrospectively the results obtained from the research of anaerobial bacteria on 1313 samples received at the Microbiology Laboratory of the "Ospedale Civile di Ivrea" over a period of 31 months (6/1/86-12/31/88). From this evaluation, high percentages of detection of anaerobic bacteria are emerging in the following infections: appendiculare abscesses (60%), intestinal operations (71%), wounds (57%), tubovarian abscesses (100%), as well as thoracic empyema (50%). Also relevant are the isolations from skin and subcutaneous tissues: breast infections (50%) preputial infections (60%), perineal and perirectal abscesses (60%). The incident of anaerobic bacteria in bacteriemia is 17%. The most representative anaerobic bacteria group are: Bacteroides spp. (56%), Peptostreptococcus spp. (12%), Propionibacterium spp. (9%), Fusobacterium spp. (7%) Clostridium spp. (6%), Veillonella spp. and Eubacterium spp. (3%). In the intraabdominal infections prevails the Bacteroides group, particularly fragilis species, while in the skin and subcutaneous infections prevails the Peptostreptococcus group.

Endocarditis caused by anaerobic bacteria.

Science.gov (United States)

Kestler, M; Muñoz, P; Marín, M; Goenaga, M A; Idígoras Viedma, P; de Alarcón, A; Lepe, J A; Sousa Regueiro, D; Bravo-Ferrer, J M; Pajarón, M; Costas, C; García-López, M V; Hidalgo-Tenorio, C; Moreno, M; Bouza, E

2017-10-01

Infective endocarditis (IE) caused by anaerobic bacteria is a rare and poorly characterized disease. Most data reported in the literature are from case reports [1-3]. Therefore, we assessed the situation of anaerobic IE (AIE) in Spain using the database of the Spanish Collaboration on Endocarditis (GAMES). We performed a prospective study from 2008 to 2016 in 26 Spanish centers. We included 2491 consecutive cases of definite IE (Duke criteria). Anaerobic bacteria caused 22 cases (0.9%) of definite IE. Median age was 66 years (IQR, 56-73), and 19 (86.4%) patients were men. Most patients (14 [63.6%]) had prosthetic valve IE and all episodes were left-sided: aortic valves, 12 (54.5%); and mitral valves, 8 (36.4%). The most common pathogens were Propionibacterium acnes (14 [63.6%]), Lactobacillus spp (3 [13.63%]), and Clostridium spp. (2 [9.0%]), and the infection was mainly odontogenic. Fifteen of the 22 patients (68.2%) underwent cardiac surgery. Mortality was 18.2% during admission and 5.5% after 1 year of follow-up. When patients with AIE were compared with the rest of the cohort, we found that although those with AIE had a similar age and Charlson comorbidity index, they were more likely to have community-acquired IE (86.4% vs. 60.9%, p = 0.01), have undergone cardiac surgery (68.2% vs 48.7% p = 0.06), and have had lower mortality rates during admission (18.2% vs. 27.3%). IE due to anaerobic bacteria is an uncommon disease that affects mainly prosthetic valves and frequently requires surgery. Otherwise, there are no major differences between AIE and IE caused by other microorganisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

Conditions associated with Clostridium sporogenes growth as a surrogate for Clostridium botulinum in nonthermally processed canned butter.

Science.gov (United States)

Taylor, R H; Dunn, M L; Ogden, L V; Jefferies, L K; Eggett, D L; Steele, F M

2013-05-01

The objective of this study was to better understand the effect of butter composition and emulsion structure on growth and survival of Clostridium sporogenes, used as a surrogate for C. botulinum in canned butter. The lack of a thermal process step in commercially available canned butter raises questions of potential safety, because it is hermetically sealed and generally exhibits anaerobic growth conditions, which are optimal for Clostridium botulinum growth. Without thermal processing, low-acid canned foods must have inhibitory factors present to prevent C. botulinum growth. Some potential intrinsic inhibitory factors, or hurdles, within butter include: reduced water activity, acidity in cultured products, elevated salt content, and the micro-droplet nature of the aqueous phase in the butter emulsion. It was hypothesized that a normal, intact butter emulsion would have sufficient hurdles to prevent C. botulinum growth, whereas a broken butter emulsion would result in a coalesced aqueous phase that would allow for C. botulinum growth. Batch-churned butter was inoculated with C. sporogenes; butter samples with varying salt contents (0, 0.8, 1.6, and 2.4% wt/wt NaCl) were prepared and stored in coated steel cans for varying times (1 or 2 wk) and temperatures (22 or 41°C) to determine temperature and emulsion structure effects on C. sporogenes growth. Samples stored at 41°C showed a significant increase in C. sporogenes growth compared with those stored at 22°C. Furthermore, NaCl addition was found to have a significant effect on C. sporogenes growth, with 0.8% NaCl promoting more growth than 0%, but with decreases in growth observed at 1.6 and 2.4%. Uninoculated control plates were also found to have bacterial growth; this growth was attributed to other anaerobic bacteria present within the cream. It was concluded that removal of the hurdle created by the micro-droplet size of the emulsion aqueous phase could result in C. botulinum growth even at elevated salt

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

DEFF Research Database (Denmark)

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

2006-01-01

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

Anaerobic digestion as final step of a cellulosic ethanol biorefinery:

DEFF Research Database (Denmark)

Uellendahl, Hinrich; Ahring, Birgitte Kiær

2010-01-01

) and mesophilic (388C) operation of the UASB reactor was investigated. At an OLR of 3.5 kg- VS/(m3 day) a methane yield of 340 L/kg-VS was achieved for thermophilic operation (538C) while 270 L/kg-VS was obtained under mesophilic conditions (388C). For loading rates higher than 5 kg-VS/(m3 day) the methane yields...... of suspended matter reduced the degradation efficiency. The retention time of the anaerobic system could be reduced from 70 to 7 h by additional removal of suspended matter by clarification. Implementation of the biogas production from the fermentation effluent accounted for about 30% higher carbon utilization...

Alcohol Selectivity in a Synthetic Thermophilic n-Butanol Pathway Is Driven by Biocatalytic and Thermostability Characteristics of Constituent Enzymes.

Science.gov (United States)

Loder, Andrew J; Zeldes, Benjamin M; Garrison, G Dale; Lipscomb, Gina L; Adams, Michael W W; Kelly, Robert M

2015-10-01

n-Butanol is generated as a natural product of metabolism by several microorganisms, but almost all grow at mesophilic temperatures. A synthetic pathway for n-butanol production from acetyl coenzyme A (acetyl-CoA) that functioned at 70°C was assembled in vitro from enzymes recruited from thermophilic bacteria to inform efforts for engineering butanol production into thermophilic hosts. Recombinant versions of eight thermophilic enzymes (β-ketothiolase [Thl], 3-hydroxybutyryl-CoA dehydrogenase [Hbd], and 3-hydroxybutyryl-CoA dehydratase [Crt] from Caldanaerobacter subterraneus subsp. tengcongensis; trans-2-enoyl-CoA reductase [Ter] from Spirochaeta thermophila; bifunctional acetaldehyde dehydrogenase/alcohol dehydrogenase [AdhE] from Clostridium thermocellum; and AdhE, aldehyde dehydrogenase [Bad], and butanol dehydrogenase [Bdh] from Thermoanaerobacter sp. strain X514) were utilized to examine three possible pathways for n-butanol. These pathways differed in the two steps required to convert butyryl-CoA to n-butanol: Thl-Hbd-Crt-Ter-AdhE (C. thermocellum), Thl-Hbd-Crt-Ter-AdhE (Thermoanaerobacter X514), and Thl-Hbd-Crt-Ter-Bad-Bdh. n-Butanol was produced at 70°C, but with different amounts of ethanol as a coproduct, because of the broad substrate specificities of AdhE, Bad, and Bdh. A reaction kinetics model, validated via comparison to in vitro experiments, was used to determine relative enzyme ratios needed to maximize n-butanol production. By using large relative amounts of Thl and Hbd and small amounts of Bad and Bdh, >70% conversion to n-butanol was observed in vitro, but with a 60% decrease in the predicted pathway flux. With more-selective hypothetical versions of Bad and Bdh, >70% conversion to n-butanol is predicted, with a 19% increase in pathway flux. Thus, more-selective thermophilic versions of Bad, Bdh, and AdhE are needed to fully exploit biocatalytic n-butanol production at elevated temperatures. Copyright © 2015, American Society for

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

Science.gov (United States)

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

2017-11-30

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

Activity of OPT-80, a novel macrocycle, compared with those of eight other agents against selected anaerobic species.

Science.gov (United States)

Credito, Kim L; Appelbaum, Peter C

2004-11-01

Agar dilution MIC was used to compare activities of OPT-80, linezolid, vancomycin, teicoplanin, quinupristin/dalfopristin, amoxicillin/clavulanate, imipenem, clindamycin, and metronidazole against 350 gram-positive and -negative anaerobes. OPT-80 was active against gram-positive strains only, especially Clostridium spp. (85 strains tested, including 21 strains of C. difficile), with MICs ranging between

Optimising the anaerobic co-digestion of urban organic waste using dynamic bioconversion mathematical modelling

DEFF Research Database (Denmark)

Fitamo, Temesgen Mathewos; Boldrin, Alessio; Dorini, G.

2016-01-01

Mathematical anaerobic bioconversion models are often used as a convenient way to simulate the conversion of organic materials to biogas. The aim of the study was to apply a mathematical model for simulating the anaerobic co-digestion of various types of urban organic waste, in order to develop...... in a continuously stirred tank reactor. The model's outputs were validated with experimental results obtained in thermophilic conditions, with mixed sludge as a single substrate and urban organic waste as a co-substrate at hydraulic retention times of 30, 20, 15 and 10 days. The predicted performance parameter...... (methane productivity and yield) and operational parameter (concentration of ammonia and volatile fatty acid) values were reasonable and displayed good correlation and accuracy. The model was later applied to identify optimal scenarios for an urban organic waste co-digestion process. The simulation...

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

Directory of Open Access Journals (Sweden)

Geng Wu

2017-07-01

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

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

Science.gov (United States)

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

2017-01-01

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

Characterization of a unique class C acid phosphatase from Clostridium perfringens.

Science.gov (United States)

Reilly, Thomas J; Chance, Deborah L; Calcutt, Michael J; Tanner, John J; Felts, Richard L; Waller, Stephen C; Henzl, Michael T; Mawhinney, Thomas P; Ganjam, Irene K; Fales, William H

2009-06-01

Clostridium perfringens is a gram-positive anaerobe and a pathogen of medical importance. The detection of acid phosphatase activity is a powerful diagnostic indicator of the presence of C. perfringens among anaerobic isolates; however, characterization of the enzyme has not previously been reported. Provided here are details of the characterization of a soluble recombinant form of this cell-associated enzyme. The denatured enzyme was approximately 31 kDa and a homodimer in solution. It catalyzed the hydrolysis of several substrates, including para-nitrophenyl phosphate, 4-methylumbelliferyl phosphate, and 3' and 5' nucleoside monophosphates at pH 6. Calculated K(m)s ranged from 0.2 to 0.6 mM with maximum velocity ranging from 0.8 to 1.6 micromol of P(i)/s/mg. Activity was enhanced in the presence of some divalent cations but diminished in the presence of others. Wild-type enzyme was detected in all clinical C. perfringens isolates tested and found to be cell associated. The described enzyme belongs to nonspecific acid phosphatase class C but is devoid of lipid modification commonly attributed to this class.

Clostridium septicum Gas Gangrene in Colon Cancer: Importance of Early Diagnosis

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Sowmya Nanjappa

2015-01-01

Full Text Available The Clostridia species are responsible for some of the deadliest diseases including gas gangrene, tetanus, and botulism. Clostridium septicum is a rare subgroup known to cause atraumatic myonecrosis and is associated with colonic malignancy or immunosuppression. It is a Gram-positive, anaerobic, spore-forming bacillus found in the gastrointestinal tract and can lead to direct, spontaneous infections of the bowel and peritoneal cavity. The anaerobic glycolysis of the tumor produces an acidic, hypoxic environment favoring germination of clostridial spores. Tumor-induced mucosal ulceration allows for translocation of sporulated bacteria from the bowel into the bloodstream, leading to fulminant sepsis. C. septicum bacteremia can have a variable presentation and is associated with greater than 60% mortality rate. The majority of deaths occur within the first 24 hours if diagnosis and appropriate treatment measures are not promptly started. We report a case of abdominal myonecrosis in a patient with newly diagnosed colon cancer. The aim of this study is to stress the importance of maintaining a high suspicion of C. septicum infection in patients with underlying colonic malignancy.

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

DEFF Research Database (Denmark)

Chang, Tinghong; Yao, Shuo

2011-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1983-02-01

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

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

Science.gov (United States)

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

2010-02-01

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

EPIDEMIOLOGIC INVESTIGATION OF CLOSTRIDIUM DIFFICILE AND CLOSTRIDIUM PERFRINGENS IN HEALTHY HORSES

DEFF Research Database (Denmark)

Schoster, Angelika; Arroyo, Luis; Staempfli, Henry

Clostridium difficile and Clostridium perfringens are important causes of equine colitis but can also be found in healthy individuals. Epidemiologic information is restricted to cross-sectional studies of fecal shedding with little information on prevalence in gastrointestinal compartments other ...... supports results of previous studies that indicate this organism is rare in healthy horses.......Clostridium difficile and Clostridium perfringens are important causes of equine colitis but can also be found in healthy individuals. Epidemiologic information is restricted to cross-sectional studies of fecal shedding with little information on prevalence in gastrointestinal compartments other...... than feces and variability in shedding over time. The objectives were to investigate the presence of C. difficile and C. perfringens in healthy horses over time and assess prevalence in different gastrointestinal compartments. Feces were collected monthly from 25 horses for one year. Ingesta were...

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

Science.gov (United States)

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

2012-05-25

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

Hygienization performances of innovative sludge treatment solutions to assure safe land spreading.

Science.gov (United States)

Levantesi, C; Beimfohr, C; Blanch, A R; Carducci, A; Gianico, A; Lucena, F; Tomei, M C; Mininni, G

2015-05-01

The present research aims at the evaluation of the hygienization performances of innovative sludge treatment processes applied for the separated treatment of secondary sludge. Namely, two digestion pretreatments (sonication and thermal hydrolysis) and two sequential biological processes (mesophilic/thermophilic and anaerobic/aerobic digestion) were compared to the mesophilic (MAD) and thermophilic anaerobic digestion (TAD). Microbial indicators (Escherichia coli, somatic coliphages and Clostridium perfringens spores) and pathogens (Salmonella and enteroviruses), which show different resistances to treatment processes, were monitored in untreated and treated sludge. Overall, microbial load in secondary sludge was shown to be similar or lower than previously reported in literature for mixed sludge. Notably, the anaerobic/aerobic digestion process increased the removal of E. coli and somatic coliphages compared to the simple MAD and always achieved the hygienization requirement (2-log-unit removal of E. coli) proposed by EU Commission in the 3rd Working Document on sludge (April 2000) for the use of treated sludges in agriculture with restriction on their application. The microbial quality limits for the unrestricted use of sludge in agriculture (no Salmonella in 50 g wet weight (WW) and E. coli <500 CFU/g) were always met when thermal digestion or pretreatment was applied; however, the required removal level (6-log-unit removal of E. coli) could not be assessed due to the low level of this microorganism in raw sludge. Observed levels of indicator removal showed a higher resistance of viral particles to thermal treatment compared with bacterial cells and confirmed the suitability of somatic coliphages as indicators in thermal treatment processes.

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

Science.gov (United States)

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

2015-01-01

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

[Role of obligate anaerobes in infections in hospitalized patients and therapeutic options].

Science.gov (United States)

Wróblewska, Marta; Rokosz, Alicja; Sawicka-Grzelak, Anna; Kot, Katarzyna; Luczak, Mirosław

2005-01-01

Monitoring of prevalence and antibiotic susceptibility of strictly anaerobic bacteria, causing infections in hospitalized patients, constitutes a part of a program for prudent use of antibiotics. The aim of the study was to assess prevalence of strictly anaerobic bacteria in patients hospitalized in a tertiary care hospital in 2001-2002 with reference to empiric antibiotic therapy. The most common gram-positive bacteria were Clostridium difficile--27.7%, Peptostreptococcus spp. and Peptoniphilus asaccharolyticus--21.9% and Actinomyces spp.--11.1%. There was an increase in the number of stool samples positive for C. difficile toxins A and B from 39.4% in 2001 to 59.0% in 2002. The results of susceptibility testing of gram-positive isolates showed the highest percentages of strains susceptible to piperacilin/tazobactam--99.6%, ticarcillin/clavulanate--98.5%, imipenem--98.5%, amoxicillin/clavulanate--97.4% and piperacillin--97.4%. The most prevalent gram-negative anaerobes were strains of Bacteroides spp.--43.1%, Prevotella spp.--35.8% and Fusobacterium spp.--11.0%. All tested strains of gram-negative bacteria were susceptible to metronidazole, piperacilin/tazobactam, ticarcillin/clavulanate and imipenem. In the analyzed population beta-lactam antibiotics with beta-lactamase inhibitors, carbapenems and metronidazole may be used in empiric therapy of infections caused by strictly anaerobic bacteria.

Thermophilic biofiltration of benzene and toluene.

Science.gov (United States)

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

2007-12-01

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

Anaerobic digestion for treatment of stillage from cellulosic bioethanol production.

Science.gov (United States)

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

2013-09-01

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

Microbial degradation of 4-monobrominated diphenyl ether with anaerobic sludge

International Nuclear Information System (INIS)

Shih, Yang-hsin; Chou, Hsi-Ling; Peng, Yu-Huei

2012-01-01

Highlights: ► BDE-3 was degraded with two anaerobes in different rates. ► Glucose addition augment the debromination efficiencies. ► Hydrogen gas was detected and relative microbes were identified. ► Extra-carbon source enhanced degradation partial due to H 2 -generation bacteria. - Abstract: Polybrominated diphenyl ethers (PBDEs) are widely used flame retardant additives for many plastic and electronic products. Owing to their ubiquitous distribution in the environment, multiple toxicity to humans, and increasing accumulation in the environment, the fate of PBDEs is of serious concern for public safety. In this study, the degradation of 4-monobrominated diphenyl ether (BDE-3) in anaerobic sludge and the effect of carbon source addition were investigated. BDE-3 can be degraded by two different anaerobic sludge samples. The by-products, diphenyl ether (DE) and bromide ions, were monitored, indicating the reaction of debromination within these anaerobic samples. Co-metabolism with glucose facilitated BDE-3 biodegradation in terms of kinetics and efficiency in the Jhongsing sludge. Through the pattern of amplified 16S rRNA gene fragments in denatured gradient gel electrophoresis (DGGE), the composition of the microbial community was analyzed. Most of the predominant microbes were novel species. The fragments enriched in BDE-3-degrading anaerobic sludge samples are presumably Clostridium sp. This enrichment coincides with the H 2 gas generation and the facilitation of debromination during the degradation process. Findings of this study provide better understanding of the biodegradation of brominated DEs and can facilitate the prediction of the fate of PBDEs in the environment.

Investigation into the effect of high concentrations of volatile fatty acids in anaerobic digestion on methanogenic communities

Energy Technology Data Exchange (ETDEWEB)

Franke-Whittle, Ingrid H., E-mail: ingrid.whittle@uibk.ac.at [Institut für Mikrobiologie, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck (Austria); Walter, Andreas [Institut für Mikrobiologie, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck (Austria); Ebner, Christian [Abwasserverband Zirl und Umgebung, Meilbrunnen 5, 6170 Zirl (Austria); Insam, Heribert [Institut für Mikrobiologie, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck (Austria)

2014-11-15

Highlights: • Different methanogenic communities in mesophilic and thermophilic reactors. • High VFA levels do not cause major changes in archaeal communities. • Real-time PCR indicated greater diversity than ANAEROCHIP microarray. - Abstract: A study was conducted to determine whether differences in the levels of volatile fatty acids (VFAs) in anaerobic digester plants could result in variations in the indigenous methanogenic communities. Two digesters (one operated under mesophilic conditions, the other under thermophilic conditions) were monitored, and sampled at points where VFA levels were high, as well as when VFA levels were low. Physical and chemical parameters were measured, and the methanogenic diversity was screened using the phylogenetic microarray ANAEROCHIP. In addition, real-time PCR was used to quantify the presence of the different methanogenic genera in the sludge samples. Array results indicated that the archaeal communities in the different reactors were stable, and that changes in the VFA levels of the anaerobic digesters did not greatly alter the dominating methanogenic organisms. In contrast, the two digesters were found to harbour different dominating methanogenic communities, which appeared to remain stable over time. Real-time PCR results were inline with those of microarray analysis indicating only minimal changes in methanogen numbers during periods of high VFAs, however, revealed a greater diversity in methanogens than found with the array.

Fournier's gangrene caused by Actinomyces funkei, Fusobacterium gonidiaformans and Clostridium hathewayi.

Science.gov (United States)

Tena, Daniel; Losa, Cristina; Medina-Pascual, María José; Sáez-Nieto, Juan Antonio

2014-06-01

We report the first case of Fournier's gangrene caused by three unusual anaerobic organisms: Actinomyces funkei, Fusobacterium gonidiaformans and Clostridium hathewayi. The infection occurred in a 73-year-old man without typical risk factors for the development of Fournier's gangrene. Clinical outcome was good after prolonged antibiotic treatment and extensive debridement of the perineum. The case suggests that A. funkei, F. gonidiaformans and C. hathewayi should be considered as potential pathogens of Fournier's gangrene. Human infections caused by these organisms are very rare but can be underestimated because correct identification is very difficult, especially in polymicrobial infections such as Fournier's gangrene. Copyright © 2014 Elsevier Ltd. All rights reserved.

Antibiotic Susceptibility Pattern of Aerobic and Anaerobic Bacteria Isolated From Surgical Site Infection of Hospitalized Patients.

Science.gov (United States)

Akhi, Mohammad Taghi; Ghotaslou, Reza; Beheshtirouy, Samad; Asgharzadeh, Mohammad; Pirzadeh, Tahereh; Asghari, Babak; Alizadeh, Naser; Toloue Ostadgavahi, Ali; Sorayaei Somesaraei, Vida; Memar, Mohammad Yousef

2015-07-01

Surgical Site Infections (SSIs) are infections of incision or deep tissue at operation sites. These infections prolong hospitalization, delay wound healing, and increase the overall cost and morbidity. This study aimed to investigate anaerobic and aerobic bacteria prevalence in surgical site infections and determinate antibiotic susceptibility pattern in these isolates. One hundred SSIs specimens were obtained by needle aspiration from purulent material in depth of infected site. These specimens were cultured and incubated in both aerobic and anaerobic condition. For detection of antibiotic susceptibility pattern in aerobic and anaerobic bacteria, we used disk diffusion, agar dilution, and E-test methods. A total of 194 bacterial strains were isolated from 100 samples of surgical sites. Predominant aerobic and facultative anaerobic bacteria isolated from these specimens were the members of Enterobacteriaceae family (66, 34.03%) followed by Pseudomonas aeruginosa (26, 13.4%), Staphylococcus aureus (24, 12.37%), Acinetobacter spp. (18, 9.28%), Enterococcus spp. (16, 8.24%), coagulase negative Staphylococcus spp. (14, 7.22%) and nonhemolytic streptococci (2, 1.03%). Bacteroides fragilis (26, 13.4%), and Clostridium perfringens (2, 1.03%) were isolated as anaerobic bacteria. The most resistant bacteria among anaerobic isolates were B. fragilis. All Gram-positive isolates were susceptible to vancomycin and linezolid while most of Enterobacteriaceae showed sensitivity to imipenem. Most SSIs specimens were polymicrobial and predominant anaerobic isolate was B. fragilis. Isolated aerobic and anaerobic strains showed high level of resistance to antibiotics.

Dynamics of antibiotic resistance genes and presence of putative pathogens during ambient temperature anaerobic digestion.

Science.gov (United States)

Resende, J A; Diniz, C G; Silva, V L; Otenio, M H; Bonnafous, A; Arcuri, P B; Godon, J-J

2014-12-01

This study was focused on evaluating the persistency of antimicrobial resistance (AR) genes and putative pathogenic bacteria in an anaerobic digesters operating at mesophilic ambient temperature, in two different year seasons: summer and winter. Abundance and dynamic of AR genes encoding resistance to macrolides (ermB), aminoglycosides (aphA2) and beta-lactams (blaTEM -1 ) and persistency of potentially pathogenic bacteria in pilot-scale anaerobic digesters were investigated. AR genes were determined in the influent and effluent in both conditions. Overall, after 60 days, reduction was observed for all evaluated genes. However, during the summer, anaerobic digestion was more related to the gene reduction as compared to winter. Persistency of potentially pathogenic bacteria was also evaluated by metagenomic analyses compared to an in-house created database. Clostridium, Acinetobacter and Stenotrophomonas were the most identified. Overall, considering the mesophilic ambient temperature during anaerobic digestion (summer and winter), a decrease in pathogenic bacteria detection through metagenomic analysis and AR genes is reported. Although the mesophilic anaerobic digestion has been efficient, the results may suggest medically important bacteria and AR genes persistency during the process. This is the first report to show AR gene dynamics and persistency of potentially pathogenic bacteria through metagenomic approach in cattle manure ambient temperature anaerobic digestion. © 2014 The Society for Applied Microbiology.

Tolerance of anaerobic bacteria to chlorinated solvents.

Science.gov (United States)

Koenig, Joanna C; Groissmeier, Kathrin D; Manefield, Mike J

2014-01-01

The aim of this research was to evaluate the effects of four chlorinated aliphatic hydrocarbons (CAHs), perchloroethene (PCE), carbon tetrachloride (CT), chloroform (CF) and 1,2-dichloroethane (1,2-DCA), on the growth of eight anaerobic bacteria: four fermentative species (Escherichia coli, Klebsiella sp., Clostridium sp. and Paenibacillus sp.) and four respiring species (Pseudomonas aeruginosa, Geobacter sulfurreducens, Shewanella oneidensis and Desulfovibrio vulgaris). Effective concentrations of solvents which inhibited growth rates by 50% (EC50) were determined. The octanol-water partition coefficient or log Po/w of a CAH proved a generally satisfactory measure of its toxicity. Most species tolerated approximately 3-fold and 10-fold higher concentrations of the two relatively more polar CAHs CF and 1,2-DCA, respectively, than the two relatively less polar compounds PCE and CT. EC50 values correlated well with growth rates observed in solvent-free cultures, with fast-growing organisms displaying higher tolerance levels. Overall, fermentative bacteria were more tolerant to CAHs than respiring species, with iron- and sulfate-reducing bacteria in particular appearing highly sensitive to CAHs. These data extend the current understanding of the impact of CAHs on a range of anaerobic bacteria, which will benefit the field of bioremediation.

Cellulases from Thermophilic Fungi: Recent Insights and Biotechnological Potential

Directory of Open Access Journals (Sweden)

Duo-Chuan Li

2011-01-01

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

A characterization of anaerobic colonization and associated mucosal adaptations in the undiseased ileal pouch.

LENUS (Irish Health Repository)

Smith, F M

2012-02-03

INTRODUCTION: The resolution of pouchitis with metronidazole points to an anaerobic aetiology. Pouchitis is mainly seen in patients with ulcerative colitis pouches (UCP). We have recently found that sulphate reducing bacteria (SRB), a species of strict anaerobe, colonize UCP exclusively. Herein, we aimed to correlate levels of different bacterial species (including SRB) with mucosal inflammation and morphology. METHODS: Following ethical approval, fresh faecal samples and mucosal biopsies were taken from 9 patients with UCP and 5 patients with familial adenomatous polyposis pouches (FAPP). For the purposes of comparison, faecal samples and mucosal biopsies were also taken from the stomas of 7 of the 9 patients with UC (UCS). Colonization by four types of strict anaerobes (SRB, Clostridium perfringens, Bifidobacteria and Bacteroides) as well as by three types of facultative anaerobes (Enterococci, Coliforms and Lactobacilli) was evaluated. Inflammatory scores and mucosal morphology were assessed histologically in a blinded fashion by a pathologist. RESULTS: In general, strict anaerobes predominated over facultative in the UCP (P = 0.041). SRB were present in UCP exclusively. Even after exclusion of SRB from total bacterial counts, strict anaerobes still predominated. In the UCS, facultative anaerobes predominated. Strict and facultative anaerobes were present at similar levels in the FAPP. Enterococci were present at significantly reduced levels in the UCP when compared with the UCS (P = 0.031). When levels of SRB and other anaerobic species were individually correlated with mucosal inflammation and morphology, no trends were observed. CONCLUSION: We have previously identified that SRB exclusively colonize UCP. In addition we have now identified a novel increase in the strict\\/facultative anaerobic ratio within the UCP compared to UCS. These stark differences in bacterial colonization, however, appear to have limited impact on mucosal inflammation or morphology.

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

Science.gov (United States)

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

2017-11-01

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

The Incidence of Nosocomial Toxigenic Clostridium difficile Associated Diarrhea in Tehran Tertiary Medical Centers

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Norakhoda Sadeghifard

2010-10-01

Full Text Available Clostridium difficile is the most common cause of nosocomial diarrhea. It is usually a consequence of antibiotic treatment, But sporadic cases can occur. This study was aimed to determine the frequency of the nosocomial Clostridium difficile (C. difficile associated diarrhea in Tehran University of Medical Sciences hospitals and study of antibacterial susceptibility of isolates. In this study a total of 942 stool samples from patients with nosocomial diarrhea that were hospitalized in Imam Khomeini hospital, Shariati hospital and Children clinical center were collected. The samples were cultured on a selective cycloserine cefoxitin fructose agar (CCFA and incubated in anaerobic conditions, at 37°C for 5 days. Isolates were characterized to species level by conventional biochemical tests. Bacterial cytotoxicity was assayed on tissue culture (vero. Antimicrobial sensitivity of isolated toxigenic C. difficile were investigated by kirby Beuer method (disk diffusion. Our findings show that, of the total patients, 57 toxigenic C. difficile (6.1% were isolated. Results of statistical analysis show significant differences between the rate of isolated toxigenic C. difficile and age group of patients (P

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

DEFF Research Database (Denmark)

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

2018-01-01

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

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

International Nuclear Information System (INIS)

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

2011-01-01

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

Thermophilic Sulfate-Reducing Bacteria in Cold Marine Sediment

DEFF Research Database (Denmark)

ISAKSEN, MF; BAK, F.; JØRGENSEN, BB

1994-01-01

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

Thermophilic Sulfate-Reducing Bacteria in Cold Marine Sediment

DEFF Research Database (Denmark)

ISAKSEN, MF; BAK, F.; JØRGENSEN, BB

1994-01-01

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

Toxinas de Clostridium perfringens Toxins of Clostridium perfringens

Directory of Open Access Journals (Sweden)

W. E. Morris

2009-12-01

Full Text Available Clostridium perfringens es un bacilo grampositivo anaerobio con capacidad de formar esporas. Es uno de los patógenos bacterianos con mayor distribución en el medio ambiente, ya que puede ser aislado de muestras de suelo y de agua y además forma parte de la microbiota intestinal de animales y humanos. Sin embargo, en ciertas ocasiones puede actuar como patógeno oportunista y causar enfermedades como la gangrena gaseosa, la enterotoxemia del ovino y del caprino y la disentería del cordero, entre otras. En humanos, está asociado a enfermedades como la intoxicación por alimentos, la enterocolitis necrotizante en niños y la enteritis necrótica o pigbel de las tribus de Papúa-Nueva Guinea. El renovado interés que existe actualmente en el estudio de C. perfringens como patógeno veterinario y humano, junto con el avance de la biología molecular, han hecho posible que la ciencia tenga hoy un conocimiento más profundo sobre la biología y la patogenia de esta bacteria. En esta revisión bibliográfica se discuten y actualizan los principales aspectos de la patogenia intestinal de C. perfringens teniendo en cuenta las toxinas con mayor importancia médica descritas hasta el presente.Clostridium perfringens is an anaerobic gram-positive spore-forming bacillus. It is one of the pathogens with larger distribution in the environment; it can be isolated from soil and water samples, which also belongs to the intestinal flora of animals and humans. However, on some occasions it can act as an opportunistic pathogen, causing diseases such as gas gangrene, enterotoxemia in sheep and goats and lamb dysentery, among others. In human beings, it is associated to diseases such as food poisoning, necrotic enterocolitis of the infant and necrotic enteritis or pigbel in Papua-New Guinea tribes. The renewed interest existing nowadays in the study of C. perfringens as a veterinarian and human pathogen, together with the advance of molecular biology, had enabled

Pathogen inactivation in liquid dairy manure during anaerobic and aerobic digestions

Science.gov (United States)

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

2014-12-01

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

Exploring optimal conditions for thermophilic fermentative hydrogen production from cassava stillage

Energy Technology Data Exchange (ETDEWEB)

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

2010-06-15

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

Improved cellulose conversion to bio-hydrogen with thermophilic bacteria and characterization of microbial community in continuous bioreactor

International Nuclear Information System (INIS)

Jiang, Hongyu; Gadow, Samir I.; Tanaka, Yasumitsu; Cheng, Jun; Li, Yu-You

2015-01-01

Thermophilic hydrogen fermentation of cellulose was evaluated by a long term continuous experiment and batch experiments. The continuous experiment was conducted under 55 °C using a continuously stirred tank reactor (CSTR) at a hydraulic retention time (HRT) of 10 day. A stable hydrogen yield of 15.4 ± 0.23 mol kg −1 of cellulose consumed was maintained for 190 days with acetate and butyrate as the main soluble byproducts. An analysis of the 16S rRNA sequences showed that the hydrogen-producing thermophilic cellulolytic microorganisms (HPTCM) were close to Thermoanaerobacterium thermosaccharolyticum, Clostridium sp. and Enterobacter cloacae. Batch experiment demonstrated that the highest H 2 producing activity was obtained at 55 °C and the ultimate hydrogen yield and the metabolic by-products were influenced greatly by temperatures. The effect of temperature variation showed that the activation energy for cellulose and glucose were estimated at 103 and 98.8 kJ mol −1 , respectively. - Highlights: • Continuous cellulosic-hydrogen fermentation was conducted at 55 °C. • Hydrogen yield was improved to 15.4 mol kg −1 of consumed-cellulose. • The cellulosic hydrogen bacteria were close to Clostridia and Enterobacter genus. • The mixed microflora produced H 2 within a wide range of temperatures (35 °C–65 °C). • Activation energy of cellulose and glucose were 103 and 98.8 kJ mol −1 , respectively

Thermophilic fungi in the new age of fungal taxonomy.

Science.gov (United States)

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

2015-01-01

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

Developing a technique to enhance durability of fibrous ion-exchange resin substrate for space greenhouses

Science.gov (United States)

Krivobok, A. S.; Berkovich, Yu. A.; Shcherbakova, V. A.; Chuvilskaya, N. A.

2018-02-01

One way to cut consumables for space plant growth facilities (PGF) with artificial soil in the form of fibrous ion-exchange resin substrate (FIERS) is on-board regeneration of the used medium. After crop harvest the procedure includes removal of the roots from the fibrous media with preservation of the exchanger properties and capillary structure. One type of FIERS, namely BIONA-V3ۛ, has been used in Russian prototypes of space conveyors. We describe a two-stage treatment of BIONA-V3ۛ including primary microwave heating of the used FIERS until (90 ± 5) °C in alkali-peroxide solution during 3.5 hrs. The second stage of the treatment is decomposition of root vestiges inside pores of BIONA-V3ۛ by using thermophilic and mesophilic anaerobic bacteria Clostridium thermocellum, Clostridium cellulolyticum and Cellulosilyticum lentocellum during 7-10 days at 55 °C. The two-stage procedure allows extraction of 90% dead roots from the FIERS' pores and the preservation of root zone hydro-physical properties. A posterior enrichment of the FIERS by minerals makes BIONA- V3ۛ reusable.

Biohydrogen production from soluble condensed molasses fermentation using anaerobic fermentation

Energy Technology Data Exchange (ETDEWEB)

Lay, Chyi-How; Lin, Chiu-Yue [Department of Environmental Engineering and Science, Feng Chia University, Taichung 40724 (China); Wu, Jou-Hsien; Hsiao, Chin-Lang [Department of Water Resource Engineering, Feng Chia University (China); Chang, Jui-Jen [Department of Life Sciences, National Chung Hsing University (China); Chen, Chin-Chao [Environmental Resources Laboratory, Department of Landscape Architecture, Chungchou Institute of Technology (China)

2010-12-15

Using anaerobic micro-organisms to convert organic waste to produce hydrogen gas gives the benefits of energy recovery and environmental protection. The objective of this study was to develop a biohydrogen production technology from food wastewater focusing on hydrogen production efficiency and micro-flora community at different hydraulic retention times. Soluble condensed molasses fermentation (CMS) was used as the substrate because it is sacchariferous and ideal for hydrogen production. CMS contains nutrient components that are necessary for bacterial growth: microbial protein, amino acids, organic acids, vitamins and coenzymes. The seed sludge was obtained from the waste activated sludge from a municipal sewage treatment plant in Central Taiwan. This seed sludge was rich in Clostridium sp. A CSTR (continuously stirred tank reactor) lab-scale hydrogen fermentor (working volume, 4.0 L) was operated at a hydraulic retention time (HRT) of 3-24 h with an influent CMS concentration of 40 g COD/L. The results showed that the peak hydrogen production rate of 390 mmol H{sub 2}/L-d occurred at an organic loading rate (OLR) of 320 g COD/L-d at a HRT of 3 h. The peak hydrogen yield was obtained at an OLR of 80 g COD/L-d at a HRT of 12 h. At HRT 8 h, all hydrogenase mRNA detected were from Clostridium acetobutylicum-like and Clostridium pasteurianum-like hydrogen-producing bacteria by RT-PCR analysis. RNA based hydrogenase gene and 16S rRNA gene analysis suggests that Clostridium exists in the fermentative hydrogen-producing system and might be the dominant hydrogen-producing bacteria at tested HRTs (except 3 h). The hydrogen production feedstock from CMS is lower than that of sucrose and starch because CMS is a waste and has zero cost, requiring no added nutrients. Therefore, producing hydrogen from food wastewater is a more commercially feasible bioprocess. (author)