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.

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

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.

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

Energy Technology Data Exchange (ETDEWEB)

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

1995-07-01

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

Substrate and product inhibition of hydrogen production by the extreme thermophile, Caldicellulosiruptor saccharolyticus

NARCIS (Netherlands)

Niel, van E.W.J.; Claassen, P.A.M.; Stams, A.J.M.

2003-01-01

Substrate and product inhibition of hydrogen production during sucrose fermentation by the extremely thermophilic bacterium Caldicellulosiruptor saccharolyticus was studied. The inhibition kinetics were analyzed with a noncompetitive, nonlinear inhibition model. Hydrogen was the most severe

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 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...

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...

Liquid Fuel from Heat-Loving Microorganisms: H2-Dependent Conversion of CO2 to Liquid Electrofuels by Extremely Thermophilic Archaea

Energy Technology Data Exchange (ETDEWEB)

None

2010-07-01

Electrofuels Project: NC State is working with the University of Georgia to create Electrofuels from primitive organisms called extremophiles that evolved before photosynthetic organisms and live in extreme, hot water environments with temperatures ranging from 167-212 degrees Fahrenheit The team is genetically engineering these microorganisms so they can use hydrogen to turn carbon dioxide directly into alcohol-based fuels. High temperatures are required to distill the biofuels from the water where the organisms live, but the heat-tolerant organisms will continue to thrive even as the biofuels are being distilled—making the fuel-production process more efficient. The microorganisms don’t require light, so they can be grown anywhere—inside a dark reactor or even in an underground facility.

Pyrophosphate as a central energy carrier in the hydrogen-producing extremely thermophilic Caldicellulosiruptor saccharolyticus

NARCIS (Netherlands)

Bielen, A.A.M.; Willquist, K.; Engman, J.; Oost, van der J.; Niel, van E.W.J.; Kengen, S.W.M.

2010-01-01

The role of inorganic pyrophosphate (PPi) as an energy carrier in the central metabolism of the extremely thermophilic bacterium Caldicellulosiruptor saccharolyticus was investigated. In agreement with its annotated genome sequence, cell extracts were shown to exhibit PPi-dependent

Hydrogen production from carrot pulp by the extreme thermophiles Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana

NARCIS (Netherlands)

Vrije, de G.J.; Budde, M.A.W.; Lips, S.J.J.; Bakker, R.R.; Mars, A.E.; Claassen, P.A.M.

2010-01-01

Hydrogen was produced from carrot pulp hydrolysate, untreated carrot pulp and (mixtures of) glucose and fructose by the extreme thermophiles Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana in pH-controlled bioreactors. Carrot pulp hydrolysate was obtained after enzymatic hydrolysis

Distinctive properties of high hydrogen producing extreme thermophiles, Caldicellulosiruptor saccharolyticus and Thermotaga elfii

NARCIS (Netherlands)

Niel, van E.W.J.; Budde, M.A.W.; Haas, de G.G.; Wal, van der F.J.; Claassen, P.A.M.; Stams, A.J.M.

2002-01-01

Growth and hydrogen production by two extreme thermophiles during sugar fermentation was investigated. In cultures of Caldicellulosiruptor saccharolyticus grown on sucrose and Thermotoga elfii grown on glucose stoichiometries of 3.3 mol of hydrogen and 2 mol of acetate per mol C6-sugar unit were

Discrete and structurally unique proteins (tāpirins) mediate attachment of extremely thermophilic Caldicellulosiruptor species to cellulose.

Science.gov (United States)

Blumer-Schuette, Sara E; Alahuhta, Markus; Conway, Jonathan M; Lee, Laura L; Zurawski, Jeffrey V; Giannone, Richard J; Hettich, Robert L; Lunin, Vladimir V; Himmel, Michael E; Kelly, Robert M

2015-04-24

A variety of catalytic and noncatalytic protein domains are deployed by select microorganisms to deconstruct lignocellulose. These extracellular proteins are used to attach to, modify, and hydrolyze the complex polysaccharides present in plant cell walls. Cellulolytic enzymes, often containing carbohydrate-binding modules, are key to this process; however, these enzymes are not solely responsible for attachment. Few mechanisms of attachment have been discovered among bacteria that do not form large polypeptide structures, called cellulosomes, to deconstruct biomass. In this study, bioinformatics and proteomics analyses identified unique, discrete, hypothetical proteins ("tāpirins," origin from Māori: to join), not directly associated with cellulases, that mediate attachment to cellulose by species in the noncellulosomal, extremely thermophilic bacterial genus Caldicellulosiruptor. Two tāpirin genes are located directly downstream of a type IV pilus operon in strongly cellulolytic members of the genus, whereas homologs are absent from the weakly cellulolytic Caldicellulosiruptor species. Based on their amino acid sequence, tāpirins are specific to these extreme thermophiles. Tāpirins are also unusual in that they share no detectable protein domain signatures with known polysaccharide-binding proteins. Adsorption isotherm and trans vivo analyses demonstrated the carbohydrate-binding module-like affinity of the tāpirins for cellulose. Crystallization of a cellulose-binding truncation from one tāpirin indicated that these proteins form a long β-helix core with a shielded hydrophobic face. Furthermore, they are structurally unique and define a new class of polysaccharide adhesins. Strongly cellulolytic Caldicellulosiruptor species employ tāpirins to complement substrate-binding proteins from the ATP-binding cassette transporters and multidomain extracellular and S-layer-associated glycoside hydrolases to process the carbohydrate content of lignocellulose. �

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

International Nuclear Information System (INIS)

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

2004-01-01

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

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...

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.).

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.

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

Thermophilic xylanases: from bench to bottle.

Science.gov (United States)

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

2018-01-17

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

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.

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

Science.gov (United States)

Nepomnyashchaya, Yana; Rezende, Julia; Hubert, Casey

2014-05-01

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

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

International Nuclear Information System (INIS)

Muthukkannan, N.; Murugesan, A.G.

2002-01-01

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

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

Science.gov (United States)

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

2005-10-01

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

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...

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

African Journals Online (AJOL)

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

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...

Resistance of Microorganisms to Extreme Environmental Conditions and Its Contribution to Astrobiology

Directory of Open Access Journals (Sweden)

Pabulo Henrique Rampelotto

2010-06-01

Full Text Available In the last decades, substantial changes have occurred regarding what scientists consider the limits of habitable environmental conditions. For every extreme environmental condition investigated, a variety of microorganisms have shown that not only can they tolerate these conditions, but that they also often require these extreme conditions for survival. Microbes can return to life even after hundreds of millions of years. Furthermore, a variety of studies demonstrate that microorganisms can survive under extreme conditions, such as ultracentrifugation, hypervelocity, shock pressure, high temperature variations, vacuums, and different ultraviolet and ionizing radiation intensities, which simulate the conditions that microbes could experience during the ejection from one planet, the journey through space, as well as the impact in another planet. With these discoveries, our knowledge about the biosphere has grown and the putative boundaries of life have expanded. The present work examines the recent discoveries and the principal advances concerning the resistance of microorganisms to extreme environmental conditions, and analyzes its contributions to the development of the main themes of astrobiology: the origins of life, the search for extraterrestrial life, and the dispersion of life in the Universe.

(Hyper)thermophilic Enzymes: Production and Purification

NARCIS (Netherlands)

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

2014-01-01

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

Efficient Genome Editing of a Facultative Thermophile Using Mesophilic spCas9

NARCIS (Netherlands)

Mougiakos, Ioannis; Bosma, Elleke F.; Weenink, Koen; Vossen, Eric; Goijvaerts, Kirsten; Oost, van der John; Kranenburg, van Richard

2017-01-01

Well-developed genetic tools for thermophilic microorganisms are scarce, despite their industrial and scientific relevance. Whereas highly efficient CRISPR/Cas9-based genome editing is on the rise in prokaryotes, it has never been employed in a thermophile. Here, we apply Streptococcus pyogenes

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

Science.gov (United States)

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

2004-05-01

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

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

Science.gov (United States)

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

1990-03-01

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

Energy transduction and transport processes in thermophilic bacteria

NARCIS (Netherlands)

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

1992-01-01

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

Functional genes and thermophilic microorganisms responsible for arsenite oxidation from the shallow sediment of an untraversed hot spring outlet.

Science.gov (United States)

Yang, Ye; Mu, Yao; Zeng, Xian-Chun; Wu, Weiwei; Yuan, Jie; Liu, Yichen; Guoji, E; Luo, Feng; Chen, Xiaoming; Li, Hao; Wang, Jianing

2017-05-01

Hot Springs have unique geochemical features. Microorganisms-mediated arsenite oxidation is one of the major biogeochemical processes occurred in some hot springs. This study aimed to understand the diversities of genes and microorganisms involved in arsenite oxidation from the outlet of an untraversed hot spring located at an altitude of 4226 m. Microcosm assay indicated that the microbial community from the hot spring was able to efficiently oxidize As(III) using glucose, lactic acid, yeast extract or sodium bicarbonate as the sole carbon source. The microbial community contained 7 phyla of microorganisms, of which Proteobacteria and Firmicutes are largely dominant; this composition is unique and differs significantly from those of other described hot springs. Twenty one novel arsenite oxidase genes were identified from the samples, which are affiliated with the arsenite oxidase families of α-Proteobacteria, β-Proteobacteria or Archaea; this highlights the high diversity of the arsenite-oxidizing microorganisms from the hot spring. A cultivable arsenite-oxidizer Chelatococcu sp. GHS311 was also isolated from the sample using enrichment technique. It can completely convert 75.0 mg/L As(III) into As(V) in 18 days at 45 °C. The arsenite oxidase of GHS311 shares the maximal sequence identity (84.7%) to that of Hydrogenophaga sp. CL3, a non-thermotolerant bacterium. At the temperature lower than 30 °C or higher than 65 °C, the growth of this strain was completely inhibited. These data help us to better understand the diversity and functional features of the thermophilic arsenite-oxidizing microorganisms from hot springs.

Polysaccharides from Extremophilic Microorganisms

Science.gov (United States)

Nicolaus, B.; Moriello, V. Schiano; Lama, L.; Poli, A.; Gambacorta, A.

2004-02-01

Several marine thermophilic strains were analyzed for exopolysaccharide production. The screening process revealed that a significant number of thermophilic microorganisms were able to produce biopolymers, and some of them also revealed interesting chemical compositions. We have identified four new polysaccharides from thermophilic marine bacteria, with complex primary structures and with different repetitive units: a galacto-mannane type from strain number 4004 and mannane type for the other strains. The thermophilic Bacillus thermantarcticus produces two exocellular polysaccharides (EPS 1, EPS 2) that give the colonies a typical mucous character. The exopolysaccharide fraction was produced with all substrates assayed, although a higher yield 400 mg liter-1 was obtained with mannose as carbon and energy source. NMR spectra confirmed that EPS 1 was a heteropolysaccharide of which the repeating unit was constituted by four different α-D-mannoses and three different β-D-glucoses. It seems to be close to some xantan polymers. EPS 2 was a mannan. Four different α-D-mannoses were found as the repeating unit. Production and chemical studies of biopolymers produced by halophilic archaea, Haloarcula species were also reported.

Hydraulic retention time affects stable acetate production from tofu processing wastewater in extreme-thermophilic (70°C) mixed culture fermentation.

Science.gov (United States)

Chen, Yun; Zhang, Fang; Wang, Ting; Shen, Nan; Yu, Zhong-Wei; Zeng, Raymond J

2016-09-01

Acetate is an important industrial chemical and its production from wastes via mixed culture fermentation (MCF) is economic. In this work, the effect of hydraulic retention time (HRT) on acetate production from tofu processing wastewater (TPW) in extreme-thermophilic (70°C) MCF was first investigated. It was found that long HRT (>3days) could lead to less acetate production while stable acetate production was achieved at short HRT (3days) with the yield of 0.57g-COD/g-CODTPW. The microbial community analysis showed that hydrogenotrophic methanogens (mainly Methanothermobacter) occupied up to 90% of archaea at both HRTs of 3 and 5days. However, Coprothermobacter, the main acetate-degraders, decreased from 35.74% to 10.58% of bacteria when HRT decreased from 5 to 3days, supporting the aggravation of syntrophic acetate oxidation in long HRT. This work demonstrated that HRT was a crucial factor to maintain stable acetate production from TPW in extreme-thermophilic MCF. Copyright © 2016 Elsevier Ltd. All rights reserved.

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.

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

OpenAIRE

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

1990-01-01

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

Tolerances of microorganisms to extreme environmental conditions

International Nuclear Information System (INIS)

West, J.M.; Arme, S.C.

1985-03-01

Microbial isolates from sites relevant to the disposal of radioactive wastes have been subjected to extreme environmental conditions in order to ascertain their tolerance ability. Two groups were chosen, sulphate reducing bacteria and sulphur oxidising bacteria, because of their potential effects on waste containment. They have been subjected to high temperatures, pressures and radiation (delta-emissions) in optimal media conditions and their ability to tolerate the conditions has been ascertained by epifluorescence microscopy and adenosine tri-phosphate (ATP) analysis followed by 'culture-on' to assess post experimental viability. Results indicate that the sulphate reducers in general, are more tolerant to these conditions than the sulphur oxidisers, some proving to be thermophilic. The sulphate reducer showed increased growth rates, as determined by population numbers, at 50 0 C and survived at 80 0 C, 4,500 psig (310 bar) with no subsequent loss in viability. Gamma irradiation of this group and an isolate of 10 5 rad over 4 hours had no effect on population numbers or viability. Such resistances are not apparent with the sulphur oxidisers whose numbers decreased with increasing radiation dose and are destroyed with pressure. (author)

Active sulfur cycling by diverse mesophilic and thermophilic microorganisms in terrestrial mud volcanoes of Azerbaijan.

Science.gov (United States)

Green-Saxena, A; Feyzullayev, A; Hubert, C R J; Kallmeyer, J; Krueger, M; Sauer, P; Schulz, H-M; Orphan, V J

2012-12-01

Terrestrial mud volcanoes (TMVs) represent geochemically diverse habitats with varying sulfur sources and yet sulfur cycling in these environments remains largely unexplored. Here we characterized the sulfur-metabolizing microorganisms and activity in four TMVs in Azerbaijan. A combination of geochemical analyses, biological rate measurements and molecular diversity surveys (targeting metabolic genes aprA and dsrA and SSU ribosomal RNA) supported the presence of active sulfur-oxidizing and sulfate-reducing guilds in all four TMVs across a range of physiochemical conditions, with diversity of these guilds being unique to each TMV. The TMVs varied in potential sulfate reduction rates (SRR) by up to four orders of magnitude with highest SRR observed in sediments where in situ sulfate concentrations were highest. Maximum temperatures at which SRR were measured was 60°C in two TMVs. Corresponding with these trends in SRR, members of the potentially thermophilic, spore-forming, Desulfotomaculum were detected in these TMVs by targeted 16S rRNA analysis. Additional sulfate-reducing bacterial lineages included members of the Desulfobacteraceae and Desulfobulbaceae detected by aprA and dsrA analyses and likely contributing to the mesophilic SRR measured. Phylotypes affiliated with sulfide-oxidizing Gamma- and Betaproteobacteria were abundant in aprA libraries from low sulfate TMVs, while the highest sulfate TMV harboured 16S rRNA phylotypes associated with sulfur-oxidizing Epsilonproteobacteria. Altogether, the biogeochemical and microbiological data indicate these unique terrestrial habitats support diverse active sulfur-cycling microorganisms reflecting the in situ geochemical environment. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

Bioprospecting thermophiles for cellulase production: a review.

Science.gov (United States)

Acharya, Somen; Chaudhary, Anita

2012-07-01

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

Growth of Thermophilic and Hyperthermophilic Fe(III)-Reducing Microorganisms on a Ferruginous Smectite as the Sole Electron Acceptor▿

Science.gov (United States)

Kashefi, Kazem; Shelobolina, Evgenya S.; Elliott, W. Crawford; Lovley, Derek R.

2008-01-01

Recent studies have suggested that the structural Fe(III) within phyllosilicate minerals, including smectite and illite, is an important electron acceptor for Fe(III)-reducing microorganisms in sedimentary environments at moderate temperatures. The reduction of structural Fe(III) by thermophiles, however, has not previously been described. A wide range of thermophilic and hyperthermophilic Archaea and Bacteria from marine and freshwater environments that are known to reduce poorly crystalline Fe(III) oxides were tested for their ability to reduce structural (octahedrally coordinated) Fe(III) in smectite (SWa-1) as the sole electron acceptor. Two out of the 10 organisms tested, Geoglobus ahangari and Geothermobacterium ferrireducens, were not able to conserve energy to support growth by reduction of Fe(III) in SWa-1 despite the fact that both organisms were originally isolated with solid-phase Fe(III) as the electron acceptor. The other organisms tested were able to grow on SWa-1 and reduced 6.3 to 15.1% of the Fe(III). This is 20 to 50% less than the reported amounts of Fe(III) reduced in the same smectite (SWa-1) by mesophilic Fe(III) reducers. Two organisms, Geothermobacter ehrlichii and archaeal strain 140, produced copious amounts of an exopolysaccharide material, which may have played an active role in the dissolution of the structural iron in SWa-1 smectite. The reduction of structural Fe(III) in SWa-1 by archaeal strain 140 was studied in detail. Microbial Fe(III) reduction was accompanied by an increase in interlayer and octahedral charges and some incorporation of potassium and magnesium into the smectite structure. However, these changes in the major element chemistry of SWa-1 smectite did not result in the formation of an illite-like structure, as reported for a mesophilic Fe(III) reducer. These results suggest that thermophilic Fe(III)-reducing organisms differ in their ability to reduce and solubilize structural Fe(III) in SWa-1 smectite and that SWa-1

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

OpenAIRE

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

2012-01-01

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

Bioprospecting thermophiles for cellulase production: a review

Directory of Open Access Journals (Sweden)

Somen Acharya

2012-09-01

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

Effect of xylose and nutrients concentration on ethanol production by a newly isolated extreme thermophilic bacterium

DEFF Research Database (Denmark)

Tomás, Ana Faria; Karakashev, Dimitar Borisov; Angelidaki, Irini

2011-01-01

An extreme thermophilic ethanol-producing strain was isolated from an ethanol high-yielding mixed culture, originally isolated from a hydrogen producing reactor operated at 70 °C. Ethanol yields were assessed with increasing concentrations of xylose, up to 20 g/l. The ability of the strain to gro...... product under most of the conditions tested, including in media lacking vitamins, peptone and yeast extract. The results indicate that this new organism is a promising candidate for the development of a second generation bio-ethanol production process. © IWA Publishing 2011....

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

[Conversion of acetic acid to methane by thermophiles

Energy Technology Data Exchange (ETDEWEB)

Zinder, S.H.

1993-01-01

The primary goal of this project is to obtain a better understanding of thermophilic microorganisms which convert acetic acid to CH[sub 4]. The previous funding period represents a departure from earlier research in this laboratory, which was more physiological and ecological. The present work is centered on the biochemistry of the thermophile Methanothrix sp. strain CALS-1. this organism presents a unique opportunity, with its purity and relatively rapid growth, to do comparative biochemical studies with the other major acetotrophic genus Methanosarcina. We previously found that Methanothrix is capable of using acetate at concentrations 100 fold lower than Methanosarcina. This finding suggests that there are significant differences in the pathways of methanogenesis from acetate in the two genera.

Hydrogen production from carrot pulp by the extreme thermophiles Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana

Energy Technology Data Exchange (ETDEWEB)

Vrije, Truus de; Budde, Miriam A.W.; Lips, Steef J.; Bakker, Robert R.; Mars, Astrid E.; Claassen, Pieternel A.M. [Wageningen UR, Food and Biobased Research, P.O. Box 17, 6700 AA Wageningen (Netherlands)

2010-12-15

Hydrogen was produced from carrot pulp hydrolysate, untreated carrot pulp and (mixtures of) glucose and fructose by the extreme thermophiles Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana in pH-controlled bioreactors. Carrot pulp hydrolysate was obtained after enzymatic hydrolysis of the polysaccharide fraction in carrot pulp. The main sugars in the hydrolysate were glucose, fructose, and sucrose. In fermentations with glucose hydrogen yields and productivities were similar for both strains. With fructose the hydrogen yield of C. saccharolyticus was reduced which might be related to uptake of glucose and fructose by different types of transport systems. With T. neapolitana the fructose consumption rate and consequently the hydrogen productivity were low. The hydrogen yields of both thermophiles were 2.7-2.8 mol H{sub 2}/mol hexose with 10 g/L sugars from carrot pulp hydrolysate. With 20 g/L sugars the yield of T. neapolitana was 2.4 mol H{sub 2}/mol hexose while the yield of C. saccharolyticus was reduced to 1.3 mol H{sub 2}/mol hexose due to high lactate production in the stationary growth phase. C. saccharolyticus was able to grow on carrot pulp and utilized soluble sugars and, after adaptation, pectin and some (hemi)cellulose. No growth was observed with T. neapolitana when using carrot pulp in agitated fermentations. Enzymatic hydrolysis of the polysaccharide fraction prior to fermentation increased the hydrogen yield with almost 10% to 2.3 g/kg of hydrolyzed carrot pulp. (author)

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

Energy Technology Data Exchange (ETDEWEB)

Grajek, W

1986-01-01

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

Oxygen and carbon dioxide mass transfer and the aerobic, autotrophic cultivation of moderate and extreme thermophiles : a case study related to the microbial desulfurization of coal

NARCIS (Netherlands)

Boogerd, F C; Bos, P; Kuenen, J.G.; Heijnen, J.; van der Lans, R G

Mass transfers of O(2), CO(2), and water vapor are among the key processes in the aerobic, autotrophic cultivation of moderate and extreme thermophiles. The dynamics and kinetics of these processes are, in addition to the obvious microbial kinetics, of crucial importance for the industrial

Preservation of microbial communities enriched on lignocellulose under thermophilic and high-solid conditions.

Science.gov (United States)

Yu, Chaowei; Reddy, Amitha P; Simmons, Christopher W; Simmons, Blake A; Singer, Steven W; VanderGheynst, Jean S

2015-01-01

Microbial communities enriched from diverse environments have shown considerable promise for the targeted discovery of microorganisms and enzymes for bioconversion of lignocellulose to liquid fuels. While preservation of microbial communities is important for commercialization and research, few studies have examined storage conditions ideal for preservation. The goal of this study was to evaluate the impact of preservation method on composition of microbial communities enriched on switchgrass before and after storage. The enrichments were completed in a high-solid and aerobic environment at 55 °C. Community composition was examined for each enrichment to determine when a stable community was achieved. Preservation methods included cryopreservation with the cryoprotective agents DMSO and glycerol, and cryopreservation without cryoprotective agents. Revived communities were examined for their ability to decompose switchgrass under high-solid and thermophilic conditions. High-throughput 16S rRNA gene sequencing of DNA extracted from enrichment samples showed that the majority of the shift in composition of the switchgrass-degrading community occurred during the initial three 2-week enrichments. Shifts in community structure upon storage occurred in all cryopreserved samples. Storage in liquid nitrogen in the absence of cryoprotectant resulted in variable preservation of dominant microorganisms in enriched samples. Cryopreservation with either DMSO or glycerol provided consistent and equivalent preservation of dominant organisms. A stable switchgrass-degrading microbial community was achieved after three 2-week enrichments. Dominant microorganisms were preserved equally well with DMSO and glycerol. DMSO-preserved communities required more incubation time upon revival to achieve pre-storage activity levels during high-solid thermophilic cultivation on switchgrass. Despite shifts in the community with storage, the samples were active upon revival under thermophilic and

Molecular studies on protein- and carbohydrate-converting ezymes from thermophilic bacteria

NARCIS (Netherlands)

Kluskens, L.D.

2004-01-01

Microorganisms that are able to grow at hightemperatures are calledthermophiles(>55

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

Science.gov (United States)

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

2014-01-01

Plant cell wall is mainly composed by cellulose, hemicellulose and lignin. The heterogeneous structure and composition of the hemicellulose are key impediments to its depolymerization and subsequent use in fermentation processes. Thus, this study aimed to perform a screening of thermophilic and thermotolerant filamentous fungi collected from different regions of the São Paulo state, and analyze the production of β-xylosidase and arabinanase at different temperatures. These enzymes are important to cell wall degradation and synthesis of end products as xylose and arabinose, respectively, which are significant sugars to fermentation and ethanol production. A total of 12 fungal species were analyzed and 9 of them grew at 45 °C, suggesting a thermophilic or thermotolerant character. Additionally Aspergillus thermomutatus anamorph of Neosartorya and A. parasiticus grew at 50 °C. Aspergillus niger and Aspergillus thermomutatus were the filamentous fungi with the most expressive production of β-xylosidase and arabinanase, respectively. In general for most of the tested microorganisms, β-xylosidase and arabinanase activities from mycelial extract (intracellular form) were higher in cultures grown at high temperatures (35-40 °C), while the correspondent extracellular activities were favorably secreted from cultures at 30 °C. This study contributes to catalogue isolated fungi of the state of São Paulo, and these findings could be promising sources for thermophilic and thermotolerant microorganisms, which are industrially important due to their enzymes.

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...

Enzyme activity screening of thermophilic bacteria isolated from Dusun Tua Hot Spring, Malaysia

Science.gov (United States)

Msarah, Marwan; Ibrahim, Izyanti; Aqma, Wan Syaidatul

2018-04-01

Thermophilic bacteria have biotechnological importance due to the availability of unique enzymes which are stable in extreme circumstances. The aim of this study includes to isolate thermophilic bacteria from hot spring and screen for important enzyme activities. Water samples from the Dusun Tua Hot Spring were collected and the physiochemical characterisation of water was measured. Eight thermophilic bacteria were isolated and determined to have at least three strong enzyme activity including protease, lipase, amylase, cellulase, pectinase and xylanase. The results showed that HuluC2 displayed all the enzyme activities and can be further studied.

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)

Genetic Tools and Techniques for Recombinant Expression in Thermophilic Bacillaceae

Directory of Open Access Journals (Sweden)

Eivind B. Drejer

2018-05-01

Full Text Available Although Escherichia coli and Bacillus subtilis are the most prominent bacterial hosts for recombinant protein production by far, additional species are being explored as alternatives for production of difficult-to-express proteins. In particular, for thermostable proteins, there is a need for hosts able to properly synthesize, fold, and excrete these in high yields, and thermophilic Bacillaceae represent one potentially interesting group of microorganisms for such purposes. A number of thermophilic Bacillaceae including B. methanolicus, B. coagulans, B. smithii, B. licheniformis, Geobacillus thermoglucosidasius, G. kaustophilus, and G. stearothermophilus are investigated concerning physiology, genomics, genetic tools, and technologies, altogether paving the way for their utilization as hosts for recombinant production of thermostable and other difficult-to-express proteins. Moreover, recent successful deployments of CRISPR/Cas9 in several of these species have accelerated the progress in their metabolic engineering, which should increase their attractiveness for future industrial-scale production of proteins. This review describes the biology of thermophilic Bacillaceae and in particular focuses on genetic tools and methods enabling use of these organisms as hosts for recombinant protein production.

Fermentation of Corn Fiber Hydrolysate to Lactic Acid by the Moderate Thermophile Bacillus coagulans

Science.gov (United States)

Composted manure from a dairy farm in Texas was examined for thermophilic microorganisms by enrichment in xylose broth medium. Forty randomly picked isolates were identified as strains of Bacillus coagulans by sequence analysis of rRNA genes. One strain, designated as MXL-9, could convert mixed su...

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.

Establishment of markerless gene deletion tools in thermophilic Bacillus smithii and construction of multiple mutant strains

NARCIS (Netherlands)

Bosma, E.F.; Weijer, van de A.H.P.; Vlist, L.; Vos, de W.M.; Oost, van der J.; Kranenburg, van R.

2015-01-01

BACKGROUND: Microbial conversion of biomass to fuels or chemicals is an attractive alternative for fossil-based fuels and chemicals. Thermophilic microorganisms have several operational advantages as a production host over mesophilic organisms, such as low cooling costs, reduced contamination risks

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

Directory of Open Access Journals (Sweden)

Vivian Machado Benassi

2014-12-01

Full Text Available Plant cell wall is mainly composed by cellulose, hemicellulose and lignin. The heterogeneous structure and composition of the hemicellulose are key impediments to its depolymerization and subsequent use in fermentation processes. Thus, this study aimed to perform a screening of thermophilic and thermotolerant filamentous fungi collected from different regions of the São Paulo state, and analyze the production of β-xylosidase and arabinanase at different temperatures. These enzymes are important to cell wall degradation and synthesis of end products as xylose and arabinose, respectively, which are significant sugars to fermentation and ethanol production. A total of 12 fungal species were analyzed and 9 of them grew at 45 ºC, suggesting a thermophilic or thermotolerant character. Additionally Aspergillus thermomutatus anamorph of Neosartorya and A. parasiticus grew at 50 ºC. Aspergillus niger and Aspergillus thermomutatus were the filamentous fungi with the most expressive production of β-xylosidase and arabinanase, respectively. In general for most of the tested microorganisms, β-xylosidase and arabinanase activities from mycelial extract (intracellular form were higher in cultures grown at high temperatures (35-40 ºC, while the correspondent extracellular activities were favorably secreted from cultures at 30 ºC. This study contributes to catalogue isolated fungi of the state of São Paulo, and these findings could be promising sources for thermophilic and thermotolerant microorganisms, which are industrially important due to their enzymes.

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

Science.gov (United States)

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

2014-01-01

Plant cell wall is mainly composed by cellulose, hemicellulose and lignin. The heterogeneous structure and composition of the hemicellulose are key impediments to its depolymerization and subsequent use in fermentation processes. Thus, this study aimed to perform a screening of thermophilic and thermotolerant filamentous fungi collected from different regions of the São Paulo state, and analyze the production of β-xylosidase and arabinanase at different temperatures. These enzymes are important to cell wall degradation and synthesis of end products as xylose and arabinose, respectively, which are significant sugars to fermentation and ethanol production. A total of 12 fungal species were analyzed and 9 of them grew at 45 °C, suggesting a thermophilic or thermotolerant character. Additionally Aspergillus thermomutatus anamorph of Neosartorya and A. parasiticus grew at 50 °C. Aspergillus niger and Aspergillus thermomutatus were the filamentous fungi with the most expressive production of β-xylosidase and arabinanase, respectively. In general for most of the tested microorganisms, β-xylosidase and arabinanase activities from mycelial extract (intracellular form) were higher in cultures grown at high temperatures (35–40 °C), while the correspondent extracellular activities were favorably secreted from cultures at 30 °C. This study contributes to catalogue isolated fungi of the state of São Paulo, and these findings could be promising sources for thermophilic and thermotolerant microorganisms, which are industrially important due to their enzymes. PMID:25763055

Genetic technologies for extremely thermophilic microorganisms of Sulfolobus, the only genetically tractable genus of crenarchaea.

Science.gov (United States)

Peng, Nan; Han, Wenyuan; Li, Yingjun; Liang, Yunxiang; She, Qunxin

2017-04-01

Archaea represents the third domain of life, with the information-processing machineries more closely resembling those of eukaryotes than the machineries of the bacterial counterparts but sharing metabolic pathways with organisms of Bacteria, the sister prokaryotic phylum. Archaeal organisms also possess unique features as revealed by genomics and genome comparisons and by biochemical characterization of prominent enzymes. Nevertheless, diverse genetic tools are required for in vivo experiments to verify these interesting discoveries. Considerable efforts have been devoted to the development of genetic tools for archaea ever since their discovery, and great progress has been made in the creation of archaeal genetic tools in the past decade. Versatile genetic toolboxes are now available for several archaeal models, among which Sulfolobus microorganisms are the only genus representing Crenarchaeota because all the remaining genera are from Euryarchaeota. Nevertheless, genetic tools developed for Sulfolobus are probably the most versatile among all archaeal models, and these include viral and plasmid shuttle vectors, conventional and novel genetic manipulation methods, CRISPR-based gene deletion and mutagenesis, and gene silencing, among which CRISPR tools have been reported only for Sulfolobus thus far. In this review, we summarize recent developments in all these useful genetic tools and discuss their possible application to research into archaeal biology by means of Sulfolobus models.

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.

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.

A constant flux of diverse thermophilic bacteria into the cold arctic seabed

DEFF Research Database (Denmark)

Hubert, Casey; Loy, Alexander; Nickel, Maren

2009-01-01

Microorganisms have been repeatedly discovered in environments that do not support their metabolic activity. Identifying and quantifying these misplaced organisms can reveal dispersal mechanisms that shape natural microbial diversity. Using endospore germination experiments, we estimated a stable...... supply of thermophilic bacteria into permanently cold Arctic marine sediment at a rate exceeding 108 spores per square meter per year. These metabolically and phylogenetically diverse Firmicutes show no detectable activity at cold in situ temperatures but rapidly mineralize organic matter by hydrolysis......, fermentation, and sulfate reduction upon induction at 50°C. The closest relatives to these bacteria come from warm subsurface petroleum reservoir and ocean crust ecosystems, suggesting that seabed fluid flow from these environments is delivering thermophiles to the cold ocean. These transport pathways may...

Glycoside hydrolase activities of thermophilic bacterial consortia adapted to switchgrass.

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

2011-08-15

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

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

DEFF Research Database (Denmark)

Liu, Dawei; Min, Booki; Angelidaki, Irini

2008-01-01

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

Continuous cultivation of a thermophilic bacterium Aeribacillus pallidus 418 for production of an exopolysaccharide applicable in cosmetic creams.

Science.gov (United States)

Radchenkova, N; Panchev, I; Vassilev, S; Kuncheva, M; Dobreva, S; Kambourova, M

2015-11-01

The aim of this study was to evaluate the effectiveness of continuous cultivation approach for exopolysaccharide (EPS) production by a thermophilic micro-organism and the potential of the synthesized EPS for application in cosmetic industry. Study on the ability of Aeribacillus pallidus 418, isolated as a good EPS producer, to synthesize the polymer in continuous cultures showed higher production in comparison with batch cultures. The degree of the EPS in the precipitate after continuous cultivation significantly increased. Non-Newtonian pseudoplastic and thixotropic behaviour of EPS determines the ability of the received cream to become more fluid after increasing time of application on the skin. This study demonstrates a highly efficient way for production of EPS from a continuous growth culture of A. pallidus 418 that have many advantages and can outperform batch culture by eliminating time for cleaning and sterilization of the vessel and the comparatively long lag phases before the organisms enter a brief period of high productivity. The valuable physico-chemical properties of the synthesized EPS influenced positively the properties of a commercial cream. EPSs from thermophilic micro-organisms are of special interest due to the advantages of the thermophilic processes and nonpathogenic nature of the polymer molecules. However, their industrial application is hindered by the comparatively low biomass and correspondingly EPS yield. Suggested continuous approach for EPS could have an enormous economic potential for an industrial scale production of thermophilic EPSs. © 2015 The Society for Applied Microbiology.

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

Energy Technology Data Exchange (ETDEWEB)

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

2004-07-01

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

Mining Hot Springs for Biodiversity and Novel Enzymes

DEFF Research Database (Denmark)

Islin, Sóley Ruth

organisms have proven to be a great source of novel enzymes that are valuable in a variety of industrial processes. We set out to search for novel thermophilic hydrolytic enzymes by taking samples from thermal environments around the world. We employed several different methods in achieving this, both......The existence of microbial life at extreme environments, such as hot springs, has been known for a few decades. The remarkable ability of microorganisms to withstand the extreme conditions of their habitats, has astounded scientist and pushed the limits of what was considered possible. Thermophilic...... culture-dependent as well as culture-independent methods. Each hot spring sample was enriched on various polymeric substrates at high temperatures in the search of thermophilic microorganism with the ability to degrade the substrate. Enzymatic activity of the cultures was confirmed, the most promising...

Insight into glycoside hydrolases for debranched xylan degradation from extremely thermophilic bacterium Caldicellulosiruptor lactoaceticus.

Directory of Open Access Journals (Sweden)

Xiaojing Jia

Full Text Available Caldicellulosiruptor lactoaceticus 6A, an anaerobic and extremely thermophilic bacterium, uses natural xylan as carbon source. The encoded genes of C. lactoaceticus 6A for glycoside hydrolase (GH provide a platform for xylan degradation. The GH family 10 xylanase (Xyn10A and GH67 α-glucuronidase (Agu67A from C. lactoaceticus 6A were heterologously expressed, purified and characterized. Both Xyn10A and Agu67A are predicted as intracellular enzymes as no signal peptides identified. Xyn10A and Agu67A had molecular weight of 47.0 kDa and 80.0 kDa respectively as determined by SDS-PAGE, while both appeared as homodimer when analyzed by gel filtration. Xyn10A displayed the highest activity at 80 °C and pH 6.5, as 75 °C and pH 6.5 for Agu67A. Xyn10A had good stability at 75 °C, 80 °C, and pH 4.5-8.5, respectively, and was sensitive to various metal ions and reagents. Xyn10A possessed hydrolytic activity towards xylo-oligosaccharides (XOs and beechwood xylan. At optimum conditions, the specific activity of Xyn10A was 44.6 IU/mg with beechwood xylan as substrate, and liberated branched XOs, xylobiose, and xylose. Agu67A was active on branched XOs with methyl-glucuronic acids (MeGlcA sub-chains, and primarily generated XOs equivalents and MeGlcA. The specific activity of Agu67A was 1.3 IU/mg with aldobiouronic acid as substrate. The synergistic action of Xyn10A and Agu67A was observed with MeGlcA branched XOs and xylan as substrates, both backbone and branched chain of substrates were degraded, and liberated xylose, xylobiose, and MeGlcA. The synergism of Xyn10A and Agu67A provided not only a thermophilic method for natural xylan degradation, but also insight into the mechanisms for xylan utilization of C. lactoaceticus.

Industrial relevance of thermophilic Archaea.

Science.gov (United States)

Egorova, Ksenia; Antranikian, Garabed

2005-12-01

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

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.

Dispersal of thermophilic Desulfotomaculum endospores into Baltic Sea sediments over thousands of years.

Science.gov (United States)

de Rezende, Júlia Rosa; Kjeldsen, Kasper Urup; Hubert, Casey R J; Finster, Kai; Loy, Alexander; Jørgensen, Bo Barker

2013-01-01

Patterns of microbial biogeography result from a combination of dispersal, speciation and extinction, yet individual contributions exerted by each of these mechanisms are difficult to isolate and distinguish. The influx of endospores of thermophilic microorganisms to cold marine sediments offers a natural model for investigating passive dispersal in the ocean. We investigated the activity, diversity and abundance of thermophilic endospore-forming sulfate-reducing bacteria (SRB) in Aarhus Bay by incubating pasteurized sediment between 28 and 85 °C, and by subsequent molecular diversity analyses of 16S rRNA and of the dissimilatory (bi)sulfite reductase (dsrAB) genes within the endospore-forming SRB genus Desulfotomaculum. The thermophilic Desulfotomaculum community in Aarhus Bay sediments consisted of at least 23 species-level 16S rRNA sequence phylotypes. In two cases, pairs of identical 16S rRNA and dsrAB sequences in Arctic surface sediment 3000 km away showed that the same phylotypes are present in both locations. Radiotracer-enhanced most probable number analysis revealed that the abundance of endospores of thermophilic SRB in Aarhus Bay sediment was ca. 10(4) per cm(3) at the surface and decreased exponentially to 10(0) per cm(3) at 6.5 m depth, corresponding to 4500 years of sediment age. Thus, a half-life of ca. 300 years was estimated for the thermophilic SRB endospores deposited in Aarhus Bay sediments. These endospores were similarly detected in the overlying water column, indicative of passive dispersal in water masses preceding sedimentation. The sources of these thermophiles remain enigmatic, but at least one source may be common to both Aarhus Bay and Arctic sediments.

Hexavalent uranium reduction from solid phase by thermophilic bacterium Thermoterrabacterium ferrireducens

International Nuclear Information System (INIS)

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

2005-01-01

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

Structural and physicochemical properties of polar lipids from thermophilic archaea.

Science.gov (United States)

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

2009-08-01

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

Efficient hydrogen production from the lignocellulosic energy crop Miscanthus by the extreme thermophilic bacteria Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana

Directory of Open Access Journals (Sweden)

de Vrije Truus

2009-06-01

Full Text Available Abstract Background The production of hydrogen from biomass by fermentation is one of the routes that can contribute to a future sustainable hydrogen economy. Lignocellulosic biomass is an attractive feedstock because of its abundance, low production costs and high polysaccharide content. Results Batch cultures of Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana produced hydrogen, carbon dioxide and acetic acid as the main products from soluble saccharides in Miscanthus hydrolysate. The presence of fermentation inhibitors, such as furfural and 5-hydroxylmethyl furfural, in this lignocellulosic hydrolysate was avoided by the mild alkaline-pretreatment conditions at a low temperature of 75°C. Both microorganisms simultaneously and completely utilized all pentoses, hexoses and oligomeric saccharides up to a total concentration of 17 g l-1 in pH-controlled batch cultures. T. neapolitana showed a preference for glucose over xylose, which are the main sugars in the hydrolysate. Hydrogen yields of 2.9 to 3.4 mol H2 per mol of hexose, corresponding to 74 to 85% of the theoretical yield, were obtained in these batch fermentations. The yields were higher with cultures of C. saccharolyticus compared to T. neapolitana. In contrast, the rate of substrate consumption and hydrogen production was higher with T. neapolitana. At substrate concentrations exceeding 30 g l-1, sugar consumption was incomplete, and lower hydrogen yields of 2.0 to 2.4 mol per mol of consumed hexose were obtained. Conclusion Efficient hydrogen production in combination with simultaneous and complete utilization of all saccharides has been obtained during the growth of thermophilic bacteria on hydrolysate of the lignocellulosic feedstock Miscanthus. The use of thermophilic bacteria will therefore significantly contribute to the energy efficiency of a bioprocess for hydrogen production from biomass.

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)

Investigating the potential of thermophilic species for ethanol production from industrial spent sulfite liquor

Directory of Open Access Journals (Sweden)

Michaela Weissgram

2015-10-01

Full Text Available Thermophilic microorganisms hold a great potential for bioethanol production on waste biomass, due to their ability to utilize pentoses and hexoses alike. However, to date hardly any data on thermophiles growing directly on industrial substrates like spent sulfite liquor (SSL are available. This contribution investigates the ability of Thermoanaerobacter species to utilize the main sugars in the used SSL (mannose, glucose and xylose and the effect of process parameters (pH, temperature and sugar concentration on their growth. Based on these results the strain T. mathranii was chosen for further studies. The ability of T. mathranii to grow directly on SSL was investigated and the effect of several inhibiting substances on growth was elucidated. Furthermore it was tested whether pretreatment with activated charcoal can increase the fermentability of SSL. The fermentations were evaluated based on yields and specific rates. It could be shown that T. mathranii was able to ferment all sugars in the investigated softwood SSL and fermented diluted, untreated SSL (up to 2.7% (w/w dry matter. Pretreatment with activated charcoal could slightly reduce the amount of phenols in the substrate and thus facilitate growth and ethanol production on higher SSL concentrations (up to 4.7% (w/v dry matter. Ethanol yields of 0.29-0.44 Cmmol of ethanol per Cmmol sugar were obtained on untreated and pretreated spent sulfite liquor, respectively. These results on an industrial substrate strengthen the claim that thermophilic microorganisms might be the optimal candidates for forest biorefinery.

The renaissance of life near the boiling point - at last, genetics and metabolic engineering.

Science.gov (United States)

Adams, Michael W W; Kelly, Robert M

2017-01-01

We discuss here the prospects for biotechnology of extreme thermophilic microorganisms. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

[Conversion of acetic acid to methane by thermophiles]. Progress report, May 15, 1989--May 14, 1993

Energy Technology Data Exchange (ETDEWEB)

Zinder, S.H.

1993-06-01

The primary goal of this project is to obtain a better understanding of thermophilic microorganisms which convert acetic acid to CH{sub 4}. The previous funding period represents a departure from earlier research in this laboratory, which was more physiological and ecological. The present work is centered on the biochemistry of the thermophile Methanothrix sp. strain CALS-1. this organism presents a unique opportunity, with its purity and relatively rapid growth, to do comparative biochemical studies with the other major acetotrophic genus Methanosarcina. We previously found that Methanothrix is capable of using acetate at concentrations 100 fold lower than Methanosarcina. This finding suggests that there are significant differences in the pathways of methanogenesis from acetate in the two genera.

Improved Method for Direct Detection of Environmental Microorganisms Using an Amplification of 16S rDNA Region

Science.gov (United States)

Tsujimura, M.; Akutsu, J.; Zhang, Z.; Sasaki, M.; Tajima, H.; Kawarabayasi, Y.

2004-12-01

The thermostable proteins or enzymes were expected to be capable to be utilized in many areas of industries. Many thermophilic microorganisms, which possess the thermostable proteins or enzymes, were identified from the extreme environment. However, many unidentified and uncultivable microorganisms are still remaining in the environment on the earth. It is generally said that the cultivable microorganisms are less than 1% of entire microorganisms living in the earth, remaining over 99% are still uncultivable. As an approach to the uncultivable microorganisms, the PCR amplification of 16S rDNA region using primer sets designed from the conserved region has been generally utilized for detection and community analysis of microorganism in the environment. However, the facts, that PCR amplification introduces the mutation in the amplified DNA fragment and efficiency of PCR amplification is depend on the sequences of primer sets, indicated that the improving of PCR analysis was necessary for more correct detection of microorganisms. As the result of evaluation for the quality of DNA polymerases, sequences of primers used for amplification and conditions of PCR amplification, the DNA polymerase, the primer set and the conditions for amplification, which did not amplify the DNA fragment from the DNA contaminated within the DNA polymerase itself, were successfully selected. Also the rate of mutation in the DNA fragment amplified was evaluated using this conditions and the genomic DNA from cultivable microbes as a template. The result indicated the rate of mutation introduced by PCR was approximately 0.1% to 0.125%. The improved method using these conditions and error rate calculated was applied for the analysis of microorganisms in the geothermal environment. The result indicated that four kinds of dominant microorganisms, including both of bacteria and archaea, were alive within soil in the hot spring in Tohoku Area. We would like to apply this improved method to detection

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

International Nuclear Information System (INIS)

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

2009-01-01

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

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

Science.gov (United States)

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

2010-12-01

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

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.

Biogas Upgrading via Hydrogenotrophic Methanogenesis in Two-Stage Continuous Stirred Tank Reactors at Mesophilic and Thermophilic Conditions

DEFF Research Database (Denmark)

Bassani, Ilaria; Kougias, Panagiotis; Treu, Laura

2015-01-01

This study proposes an innovative setup composed by two stage reactors to achieve biogas upgrading coupling the CO2 in the biogas with external H2 and subsequent conversion into CH4 by hydrogenotrophic methanogenesis. In this configuration, the biogas produced in the first reactor was transferred...... production and CO2 conversion was recorded. The consequent increase of pH did not inhibit the process indicating adaptation of microorganisms to higher pH levels. The effects of H2 on the microbial community were studied using high-throughput Illumina random sequences and full-length 16S rRNA genes extracted...... to the second one, where H2 was injected. This configuration was tested at both mesophilic and thermophilic conditions. After H2 addition, the produced biogas was upgraded to average CH4 content of 89% in the mesophilic reactor and 85% in the thermophilic. At thermophilic conditions, a higher efficiency of CH4...

Community dynamics and glycoside hydrolase activities of thermophilic bacterial consortia adapted to switchgrass

Energy Technology Data Exchange (ETDEWEB)

Gladden, J.M.; Allgaier, M.; Miller, C.S.; Hazen, T.C.; VanderGheynst, J.S.; Hugenholtz, P.; Simmons, B.A.; Singer, S.W.

2011-05-01

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

Metagenomic Analysis of Hot Springs in Central India Reveals Hydrocarbon Degrading Thermophiles and Pathways Essential for Survival in Extreme Environments

Science.gov (United States)

Saxena, Rituja; Dhakan, Darshan B.; Mittal, Parul; Waiker, Prashant; Chowdhury, Anirban; Ghatak, Arundhuti; Sharma, Vineet K.

2017-01-01

Extreme ecosystems such as hot springs are of great interest as a source of novel extremophilic species, enzymes, metabolic functions for survival and biotechnological products. India harbors hundreds of hot springs, the majority of which are not yet explored and require comprehensive studies to unravel their unknown and untapped phylogenetic and functional diversity. The aim of this study was to perform a large-scale metagenomic analysis of three major hot springs located in central India namely, Badi Anhoni, Chhoti Anhoni, and Tattapani at two geographically distinct regions (Anhoni and Tattapani), to uncover the resident microbial community and their metabolic traits. Samples were collected from seven distinct sites of the three hot spring locations with temperature ranging from 43.5 to 98°C. The 16S rRNA gene amplicon sequencing of V3 hypervariable region and shotgun metagenome sequencing uncovered a unique taxonomic and metabolic diversity of the resident thermophilic microbial community in these hot springs. Genes associated with hydrocarbon degradation pathways, such as benzoate, xylene, toluene, and benzene were observed to be abundant in the Anhoni hot springs (43.5–55°C), dominated by Pseudomonas stutzeri and Acidovorax sp., suggesting the presence of chemoorganotrophic thermophilic community with the ability to utilize complex hydrocarbons as a source of energy. A high abundance of genes belonging to methane metabolism pathway was observed at Chhoti Anhoni hot spring, where methane is reported to constitute >80% of all the emitted gases, which was marked by the high abundance of Methylococcus capsulatus. The Tattapani hot spring, with a high-temperature range (61.5–98°C), displayed a lower microbial diversity and was primarily dominated by a nitrate-reducing archaeal species Pyrobaculum aerophilum. A higher abundance of cell metabolism pathways essential for the microbial survival in extreme conditions was observed at Tattapani. Taken together

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

Directory of Open Access Journals (Sweden)

Torres Leticia L

2012-08-01

temperature was 75 °C. The half-life of the enzyme at this temperature was 9.2 h. Conclusions This is the first report concerning the heterologous expression of a pac gene from a thermophilic microorganism in the mesophilic host E. coli. The recombinant protein was identified as a penicillin K-deacylating thermozyme.

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

Science.gov (United States)

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

2012-08-09

the enzyme at this temperature was 9.2 h. This is the first report concerning the heterologous expression of a pac gene from a thermophilic microorganism in the mesophilic host E. coli. The recombinant protein was identified as a penicillin K-deacylating thermozyme.

TtMCO: A highly thermostable laccase-like multicopper oxidase from the thermophilic Thermobaculum terrenum

DEFF Research Database (Denmark)

Brander, Søren; Mikkelsen, Jørn Dalgaard; Kepp, Kasper Planeta

2015-01-01

This paper reports the identification, heterologous expression in Escherichia coli and characterization of TtMCO from the thermophilic bacterium Thermobaculum terrenum, the first laccase-like multi-copper oxidase (LMCO) from the distinct Phylum Chloroflexi. TtMCO has only 39% identity to its...... closest characterized homologue, CotA from Bacillus subtilis, but sequence and spectrophotometry confirmed copper coordination similar to that of LMCOs. TtMCO is extremely thermophilic with a half-time of inactivation of 2.24 days at 70 degrees C and 350 min at 80°C and pH 7, consistent...

Application of thermotolerant microorganisms for biofertilizer preparation.

Science.gov (United States)

Chen, Kuo-Shu; Lin, Yann-Shying; Yang, Shang-Shyng

2007-12-01

Intensive agriculture is practised in Taiwan, and compost application is very popular as a means of improving the soil physical properties and supplying plant nutrition. We tested the potential of inoculation with thermotolerant microorganisms to shorten the maturity and improve the quality of biofertilizer prepared by composting. Thermotolerant microorganisms were isolated from compost and reinoculated for the preparation of biofertilizer. The physical, chemical and biological properties of the biofertilizer were determined during composting. The effects of biofertilizer application on the growth and yield of rape were also studied. Among 3823 colonies of thermotolerant microorganisms, Streptomyces thermonitrificans NTU-88, Streptococcus sp. NTU-130 and Aspergillus fumigatus NTU-132 exhibited high growth rates and cellulolytic and proteolytic activities. When a mixture of rice straw and swine manure were inoculated with these isolates and composted for 61 days, substrate temperature increased initially and then decreased gradually during composting. Substrate pH increased from 7.3 to 8.5. Microbial inoculation enhanced the rate of maturity, and increased the content of ash and total and immobilized nitrogen, improved the germination rate of alfalfa seed, and decreased the content of total organic carbon and the carbon/nitrogen ratio. Biofertilizer application increased the growth and yield of rape. Inoculation of thermotolerant and thermophilic microorganisms to agricultural waste for biofertilizer preparation enhances the rate of maturity and improves the quality of the resulting biofertilizer. Inoculation of appropriate microorganisms in biofertilizer preparation might be usefully applied to agricultural situations.

(Hyper)thermophilic enzymes: production and purification.

Science.gov (United States)

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

2014-01-01

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

Differential antibiotic sensitivity determined by the large ribosomal subunit in thermophilic archaea.

OpenAIRE

Ruggero, D; Londei, P

1996-01-01

Hybrid ribosomes obtained by mixing the ribosomal subunits of the extremely thermophilic archaea Sulfolobus solfataricus and Desulfurococcus mobilis were tested for their sensitivity to selected antibiotics. It is shown that structural differences in the large ribosomal subunits determine qualitatively and quantitatively the patterns of response to alpha-sarcin and paromomycin in these species.

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.

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

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Deeksha Gaur

2012-10-01

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

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

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...

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.

Space agriculture for habitation on Mars with hyper-thermophilic aerobic composting bacteria

Science.gov (United States)

Kanazawa, S.; Ishikawa, Y.; Tomita-Yokotani, K.; Hashimoto, H.; Kitaya, Y.; Yamashita, M.; Nagatomo, M.; Oshima, T.; Wada, H.; Space Agriculture Task Force, J.

Manned Mars exploration requires recycle of materials to support human life A conceptual design is developed for space agriculture which is driven by the biologically regenerative function Hyper-thermophilic aerobic composting bacterial ecology is the core of materials recycling system to process human metabolic waste and inedible biomass and convert them to fertilizer for plants cultivation A photosynthetic reaction of plants will be driven by solar energy Water will be recycled by cultivation of plants and passing it through plant bodies Sub-surface water and atmospheric carbon dioxide are the natural resource available on Mars and these resources will be converted to oxygen and foods We envision that the agricultural system will be scaled up by importing materials from Martian environment Excess oxygen will be obtained from growing trees for structural and other components Minor elements including N P K and other traces will be introduced as fertilizers or nutrients into the agricultural materials circulation Nitrogen will be collected from Martian atmosphere We will assess biological fixation of nitrogen using micro-organisms responsible in Earth biosphere Hyper-thermophilic aerobic bacterial ecology is effective to convert waste materials into useful forms to plants This microbial technology has been well established on ground for processing sewage and waste materials For instance the hyper-thermophilic bacterial system is applied to a composting machine in a size of a trash box in home kitchen Since such a home electronics

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

Science.gov (United States)

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

2012-02-10

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

Proteolysis in hyperthermophilic microorganisms

Directory of Open Access Journals (Sweden)

Donald E. Ward

2002-01-01

Full Text Available Proteases are found in every cell, where they recognize and break down unneeded or abnormal polypeptides or peptide-based nutrients within or outside the cell. Genome sequence data can be used to compare proteolytic enzyme inventories of different organisms as they relate to physiological needs for protein modification and hydrolysis. In this review, we exploit genome sequence data to compare hyperthermophilic microorganisms from the euryarchaeotal genus Pyrococcus, the crenarchaeote Sulfolobus solfataricus, and the bacterium Thermotoga maritima. An overview of the proteases in these organisms is given based on those proteases that have been characterized and on putative proteases that have been identified from genomic sequences, but have yet to be characterized. The analysis revealed both similarities and differences in the mechanisms utilized for proteolysis by each of these hyperthermophiles and indicated how these mechanisms relate to proteolysis in less thermophilic cells and organisms.

Candidatus Nitrosocaldus cavascurensis, an Ammonia Oxidizing, Extremely Thermophilic Archaeon with a Highly Mobile Genome

OpenAIRE

Abby, Sophie S.; Melcher, Michael; Kerou, Melina; Krupovic, Mart; Stieglmeier, Michaela; Rossel, Claudia; Pfeifer, Kevin; Schleper, Christa

2018-01-01

Ammonia oxidizing archaea (AOA) of the phylum Thaumarchaeota are widespread in moderate environments but their occurrence and activity has also been demonstrated in hot springs. Here we present the first enrichment of a thermophilic representative with a sequenced genome, which facilitates the search for adaptive strategies and for traits that shape the evolution of Thaumarchaeota. Candidatus Nitrosocaldus cavascurensis has been enriched from a hot spring in Ischia, Italy. It grows optimally ...

Active microorganisms thrive among extremely diverse communities in cloud water.

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Pierre Amato

Full Text Available Clouds are key components in Earth's functioning. In addition of acting as obstacles to light radiations and chemical reactors, they are possible atmospheric oases for airborne microorganisms, providing water, nutrients and paths to the ground. Microbial activity was previously detected in clouds, but the microbial community that is active in situ remains unknown. Here, microbial communities in cloud water collected at puy de Dôme Mountain's meteorological station (1465 m altitude, France were fixed upon sampling and examined by high-throughput sequencing from DNA and RNA extracts, so as to identify active species among community members. Communities consisted of ~103-104 bacteria and archaea mL-1 and ~102-103 eukaryote cells mL-1. They appeared extremely rich, with more than 28 000 distinct species detected in bacteria and 2 600 in eukaryotes. Proteobacteria and Bacteroidetes largely dominated in bacteria, while eukaryotes were essentially distributed among Fungi, Stramenopiles and Alveolata. Within these complex communities, the active members of cloud microbiota were identified as Alpha- (Sphingomonadales, Rhodospirillales and Rhizobiales, Beta- (Burkholderiales and Gamma-Proteobacteria (Pseudomonadales. These groups of bacteria usually classified as epiphytic are probably the best candidates for interfering with abiotic chemical processes in clouds, and the most prone to successful aerial dispersion.

Bioplastics from microorganisms.

Science.gov (United States)

Luengo, José M; García, Belén; Sandoval, Angel; Naharro, Germán; Olivera, Elías R

2003-06-01

The term 'biomaterials' includes chemically unrelated products that are synthesised by microorganisms (or part of them) under different environmental conditions. One important family of biomaterials is bioplastics. These are polyesters that are widely distributed in nature and accumulate intracellularly in microorganisms in the form of storage granules, with physico-chemical properties resembling petrochemical plastics. These polymers are usually built from hydroxy-acyl-CoA derivatives via different metabolic pathways. Depending on their microbial origin, bioplastics differ in their monomer composition, macromolecular structure and physical properties. Most of them are biodegradable and biocompatible, which makes them extremely interesting from the biotechnological point of view.

Bioleaching of a low-grade nickel-copper sulfide by mixture of four thermophiles.

Science.gov (United States)

Li, Shuzhen; Zhong, Hui; Hu, Yuehua; Zhao, Jiancun; He, Zhiguo; Gu, Guohua

2014-02-01

This study investigated thermophilic bioleaching of a low grade nickel-copper sulfide using mixture of four acidophilic thermophiles. Effects of 0.2g/L l-cysteine on the bioleaching process were further evaluated. It aimed at offering new alternatives for enhancing metal recoveries from nickel-copper sulfide. Results showed a recovery of 80.4% nickel and 68.2% copper in 16-day bioleaching without l-cysteine; while 83.7% nickel and 81.4% copper were recovered in the presence of l-cysteine. Moreover, nickel recovery was always higher than copper recovery. l-Cysteine was found contributing to lower pH value, faster microbial growth, higher Oxidation-Reduction Potential (ORP), higher zeta potential and absorbing on the sulfide surfaces through amino, carboxyl and sulfhydryl groups. X-ray Diffraction (XRD) patterns of leached residues showed generation of S, jarosite and ammoniojarosite. Denaturing Gradient Gel Electrophoresis (DGGE) results revealed that l-cysteine could have variant impacts on different microorganisms and changed the microbial community composition dramatically during nickel-copper sulfide bioleaching. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

Thermophilic methanogenic Archaea in compost material: occurrence, persistence and possible mechanisms for their distribution to other environments.

Science.gov (United States)

Thummes, Kathrin; Schäfer, Jenny; Kämpfer, Peter; Jäckel, Udo

2007-12-01

Since compost is widely used as soil amendment and the fact that during the processing of compost material high amounts of microorganisms are released into the air, we investigated whether compost may act as a carrier for thermophilic methanogens to temperate soils. All eight investigated compost materials showed a clear methane production potential between 0.01 and 0.98 micromol CH(4) g dw(-1)h(-1) at 50 degrees C. Single strand conformation polymorphism (SSCP) and cloning analysis indicated the presence of Methanosarcina thermophila, Methanoculleus thermophilus, and Methanobacterium formicicum. Bioaerosols collected during the turning of a compost pile showed both a highly similar SSCP profile compared to the corresponding compost material and clear methane production during anoxic incubation in selective medium at 50 degrees C. Both observations indicated a considerable release of thermophilic methanogens into the air. To analyse the persistence of compost-borne thermophilic methanogens in temperate oxic soils, we therefore studied their potential activity in compost and compost/soil mixtures, which was brought to a meadow soil, as well as in an agricultural soil fertilised with compost. After 24h anoxic incubation at 50 degrees C, all samples containing compost showed a clear methanogenic activity, even 1 year after application. In combination with the in vitro observed resilience of the compost-borne methanogens against desiccation and UV radiation we assume that compost material acts as an effective carrier for the distribution of thermophilic methanogens by fertilisation and wind.

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...

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

Potential use of thermophilic dark fermentation effluents in photofermentative hydrogen production by Rhodobacter capsulatus

Energy Technology Data Exchange (ETDEWEB)

Ozgura, E.; Afsar, N.; Eroglu, I. [Middle East Technical University, Department of Chemical Engineering, 06531 Ankara (Turkey); De Vrije, T.; Claassen, P.A.M. [Wageningen UR, Agrotechnology and Food Sciences Group, Wageningen UR, P.O. Box 17, 6700 AA Wageningen (Netherlands); Yucel, M.; Gunduz, U. [Middle East Technical University, Department of Biology, 06531 Ankara (Turkey)

2010-12-15

Biological hydrogen production by a sequential operation of dark and photofermentation is a promising route to produce hydrogen. The possibility of using renewable resources, like biomass and agro-industrial wastes, provides a dual effect of sustainability in biohydrogen production and simultaneous waste removal. In this study, photofermentative hydrogen production on effluents of thermophilic dark fermentations on glucose, potato steam peels (PSP) hydrolysate and molasses was investigated in indoor, batch operated bioreactors. An extreme thermophile Caldicellulosiruptor saccharolyticus was used in the dark fermentation step, and Rhodobacter capsulatus (DSM1710) was used in the photofermentation step. Addition of buffer, Fe and Mo to dark fermentor effluents (DFEs) improved the overall efficiency of hydrogen production. The initial acetate concentration in the DFE needed to be adjusted to 30-40 mM by dilution to increase the yield of hydrogen in batch light-supported fermentations. The thermophilic DFEs are suitable for photofermentative hydrogen production, provided that they are supplemented with buffer and nutrients. The overall hydrogen yield of the two-step fermentations was higher than the yield of single step dark fermentations.

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

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.

16S rRNA-targeted probes for specific detection of Thermoanaerobacterium spp., Thermoanaerobacterium thermosaccharolyticum, and Caldicellulosiruptor spp. by fluorescent in situ hybridization in biohydrogen producing systems

Energy Technology Data Exchange (ETDEWEB)

O-Thong, Sompong [Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet Bg 115, DK-2800, Kgs Lyngby (Denmark); Department of Biology, Faculty of Science, Thaksin University, Patthalung 93110 (Thailand); Prasertsan, Poonsuk [Department of Industrial Biotechnology, Faculty of Agro-Industry, Prince of Songkla University, Hat-Yai, Songkhla 90112 (Thailand); Karakashev, Dimitar; Angelidaki, Irini [Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet Bg 115, DK-2800, Kgs Lyngby (Denmark)

2008-11-15

16S rRNA gene targeted oligonucleotide probes for specific detection of genera Thermoanaerobacterium (Tbm1282), Caldicellulosiruptor (Ccs432), and specie Thermoanaerobacterium thermosaccharolyticum (Tbmthsacc184) were designed and used to monitor the spatial distribution of hydrogen producing bacteria in sludge and granules from anaerobic reactors. The designed probes were checked for their specificity and then validated using fluorescence in situ hybridization with target microorganisms and non-target microorganisms. Thermoanaerobacterium spp., T. thermosaccharolyticum and Caldicellulosiruptor spp. were detected with the probes designed with coverage of 75%, 100% and 93%, respectively. Thermophilic (60 C) hydrogen producing reactors, one fed with sucrose and another, fed with palm oil mill effluent comprised of following major groups of hydrogen producers: Thermoanaerobacterium spp. (49% and 36%), T. thermosaccharolyticum (16% and 10%), phylum Firmicutes (low G+C) gram positive bacteria (15% and 27%). Extreme-thermophilic (70 C) hydrogen producing reactors, one fed with xylose and another, fed with lignocellulosic hydrolysate comprised of following major groups of hydrogen producers: Caldicellulosiruptor spp. (40.5% and 20.5%), phylum Firmicutes (low G+C) gram positive bacteria (17% and 20%), Archaea (7% and 8.5%), and Thermoanaerobacterium spp. (0% and 5%). Results obtained, showed good applicability of the probes Tbm1282, Tbmthsacc184 and Ccs432 for specific detection and quantification of thermophilic and extreme-thermophilic hydrogen producers in complex environments. (author)

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.

Bioenergetic studies of coal sulfur oxidation by extremely thermophilic bacteria. Final report, September 15, 1992--August 31, 1997

Energy Technology Data Exchange (ETDEWEB)

Kelly, R.M.; Han, C.J.

1997-12-31

Thermoacidophilic microorganisms have been considered for inorganic sulfur removal from coal because of expected improvements in rates of both biotic and abiotic sulfur oxidation reactions with increasing temperature. In this study, the bioenergetic response of the extremely thermoacidophilic archaeon, Metallosphaera sedula, to environmental changes have been examined in relation to its capacity to catalyze pyrite oxidation in coal. Given an appropriate bioenergetic challenge, the metabolic response was to utilize additional amounts of energy sources (i.e., pyrite) to survive. Of particular interest were the consequences of exposing the organism to various forms of stress (chemical, nutritional, thermal, pH) in the presence of coal pyrite. Several approaches to take advantage of stress response to accelerate pyrite oxidation by this organism were examined, including attempts to promote acquired thermal tolerance to extend its functional range, exposure to chemical uncouplers and decouplers, and manipulation of heterotrophic and chemolithotrophic tendencies to optimize biomass concentration and biocatalytic activity. Promising strategies were investigated in a continuous culture system. This study identified environmental conditions that promote better coupling of biotic and abiotic oxidation reactions to improve biosulfurization rates of thermoacidophilic microorganisms.

[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.

Molecular Phylogenetic Exploration of Bacterial Diversity in a Bakreshwar (India) Hot Spring and Culture of Shewanella-Related Thermophiles

Science.gov (United States)

Ghosh, Dhritiman; Bal, Bijay; Kashyap, V. K.; Pal, Subrata

2003-01-01

The bacterial diversity of a hot spring in Bakreshwar, India, was investigated by a culture-independent approach. 16S ribosomal DNA clones derived from the sediment samples were found to be associated with gamma-Proteobacteria, cyanobacteria, and green nonsulfur and low-GC gram-positive bacteria. The first of the above phylotypes cobranches with Shewanella, a well-known iron reducer. This phylogenetic correlation has been exploited to develop culture conditions for thermophilic iron-reducing microorganisms. PMID:12839826

Protein stability and enzyme activity at extreme biological temperatures

International Nuclear Information System (INIS)

Feller, Georges

2010-01-01

Psychrophilic microorganisms thrive in permanently cold environments, even at subzero temperatures. To maintain metabolic rates compatible with sustained life, they have improved the dynamics of their protein structures, thereby enabling appropriate molecular motions required for biological activity at low temperatures. As a consequence of this structural flexibility, psychrophilic proteins are unstable and heat-labile. In the upper range of biological temperatures, thermophiles and hyperthermophiles grow at temperatures > 100 0 C and synthesize ultra-stable proteins. However, thermophilic enzymes are nearly inactive at room temperature as a result of their compactness and rigidity. At the molecular level, both types of extremophilic proteins have adapted the same structural factors, but in opposite directions, to address either activity at low temperatures or stability in hot environments. A model based on folding funnels is proposed accounting for the stability-activity relationships in extremophilic proteins. (topical review)

Status on Science and Application of Thermophilic Anaerobic Digestion

DEFF Research Database (Denmark)

Ahring, Birgitte Kiær

1994-01-01

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

Cloning, expression, crystallization and preliminary X-ray characterization of cytochrome c552 from a moderate thermophilic bacterium, Hydrogenophilus thermoluteolus

International Nuclear Information System (INIS)

Ichiki, Shin-ichi; Nakamura, Shota; Ohkubo, Tadayasu; Kobayashi, Yuji; Hasegawa, Jun; Uchiyama, Susumu; Nishihara, Hirofumi; Mizuta, Keiko; Sambongi, Yoshihiro

2005-01-01

Cytochrome c 552 of a moderate thermophile, H. thermoluteolus, was overexpressed in E. coli and crystallized for X-ray diffraction study. The amino-acid sequence of cytochrome c 552 (PH c 552 ) from a moderately thermophilic bacterium, Hydrogenophilus thermoluteolus, was more than 50% identical to that of cytochrome c from an extreme thermophile, Hydrogenobacter thermophilus (HT c 552 ), and from a mesophile, Pseudomonas aeruginosa (PA c 551 ). The PH c 552 gene was overexpressed as a correctly processed holoprotein in the Escherichia coli periplasm. The overexpressed PH c 552 has been crystallized by vapour diffusion from polyethylene glycol 4000 pH 6.5. The crystals belong to space group C222 1 , with unit-cell parameters a = 48.98, b = 57.99, c = 56.20 Å. The crystals diffract X-rays to around 2.1 Å resolution

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

Science.gov (United States)

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

2015-02-01

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

Extreme thermophilic ethanol production from rapeseed straw: using the newly isolated Thermoanaerobacter pentosaceus and combining it with Saccharomyces cerevisiae in a two-step process

DEFF Research Database (Denmark)

Tomás, Ana Faria; Karagöz, Pınar; Karakashev, Dimitar Borisov

2013-01-01

from the liquid fraction of pretreated rapeseed straw, without any dilution or need for additives. However, when the hydrolysate was used undiluted the ethanol yield was only 37% compared to yield of the control, in which pure sugars in synthetic medium were used. The decrease of ethanol yield...... showed that the two strains together could achieve up to 85% of the theoretical ethanol yield based on the sugar composition of the rapeseed straw, which was 14% and 50% higher compared to the yield with the yeast or the bacteria alone, respectively. Biotechnol. Bioeng. © 2012 Wiley Periodicals, Inc.......The newly isolated extreme thermophile Thermoanaerobacter pentosaceus was used for ethanol production from alkaline-peroxide pretreated rapeseed straw (PRS). Both the liquid and solid fractions of PRS were used. T. pentosaceus was able to metabolize the typical process inhibitors present...

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.

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

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

NARCIS (Netherlands)

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

2002-01-01

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

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...

Identification and Characterization of Extremophile Microorganisms with Significance to Astrobiology

Science.gov (United States)

Bej, Asim K.

2003-01-01

It is now well recognized that microorganisms thrive in extreme ecological conditions such as geothermal vents, polar region, acid and alkaline lakes, and the cold pressurized depth of the ocean floor of this planet. Morphological, physiological, biochemical and genetic adaptations to extreme environments by these extremophile microorganisms have generated immense interest amongst astrobiologists who increasingly believe in the existence of extraterrestrial life. The evidence collected by NASA's space probe Galileo suggested the presence of liquid water and volcanic activity on Mars and Jupiter's satellite Europa. Volcanic activity provides some of the heat necessary to keep the water on Europa from freezing that could provide important dissolved chemicals needed by living organisms. The possibility of the existence of hypersaline alkaline lakes and evaporites confined within closed volcanic basins and impact craters on Mars, and a layer of liquid water under the ice on Europa provide sufficient 'raison d'etre' to study microorganisms in similar extreme environments on Earth, which could provide us with a model that would help establish the existence of extraterrestrial life on other planetary bodies. The objectives of the summer research project were as follows: (1) application of molecular approaches to help establish new species of extremophile microorganisms isolated from a hypersaline alkaline lake; and (2) identification of a major cold-shock gene (cspA) homolog from a psychrotolerant microorganism, PmagG1.

Structural Insights into the Thermophilic Adaption Mechanism of Endo-1,4-β-Xylanase from Caldicellulosiruptor owensensis.

Science.gov (United States)

Liu, Xin; Liu, Tengfei; Zhang, Yuebin; Xin, Fengjiao; Mi, Shuofu; Wen, Boting; Gu, Tianyi; Shi, Xinyuan; Wang, Fengzhong; Sun, Lichao

2018-01-10

Xylanases (EC 3.2.1.8) are a kind of enzymes degrading xylan to xylooligosaccharides (XOS) and have been widely used in a variety of industrial applications. Among them, xylanases from thermophilic microorganisms have distinct advantages in industries that require high temperature conditions. The CoXynA gene, encoding a glycoside hydrolase (GH) family 10 xylanase, was identified from thermophilic Caldicellulosiruptor owensensis and was overexpressed in Escherichia coli. Recombinant CoXynA showed optimal activity at 90 °C with a half-life of about 1 h at 80 °C and exhibited highest activity at pH 7.0. The activity of CoXynA activity was affected by a variety of cations. CoXynA showed distinct substrate specificities for beechwood xylan and birchwood xylan. The crystal structure of CoXynA was solved and a molecular dynamics simulation of CoXynA was performed. The relatively high thermostability of CoXynA was proposed to be due to the increased overall protein rigidity resulting from the reduced length and fluctuation of Loop 7.

A Cascade of Thermophilic Enzymes As an Approach to the Synthesis of Modified Nucleotides.

Science.gov (United States)

Esipov, R S; Abramchik, Yu A; Fateev, I V; Konstantinova, I D; Kostromina, M A; Muravyova, T I; Artemova, K G; Miroshnikov, A I

2016-01-01

We propose a new approach for the synthesis of biologically important nucleotides which includes a multi-enzymatic cascade conversion of D -pentoses into purine nucleotides. The approach exploits nucleic acid exchange enzymes from thermophilic microorganisms: ribokinase, phosphoribosylpyrophosphate synthetase, and adenine phosphoribosyltransferase. We cloned the ribokinase gene from Thermus sp . 2.9, as well as two different genes of phosphoribosylpyrophosphate synthetase (PRPP-synthetase) and the adenine phosphoribosyltransferase (APR-transferase) gene from Thermus thermophilus HB27 into the expression vectors, generated high-yield E. coli producer strains, developed methods for the purification of the enzymes, and investigated enzyme substrate specificity. The enzymes were used for the conversion of D -pentoses into 5-phosphates that were further converted into 5-phospho-α- D -pentofuranose 1-pyrophosphates by means of ribokinase and PRPP-synthetases. Target nucleotides were obtained through the condensation of the pyrophosphates with adenine and its derivatives in a reaction catalyzed by APR-transferase. 2-Chloro- and 2-fluoroadenosine monophosphates were synthesized from D -ribose and appropriate heterobases in one pot using a system of thermophilic enzymes in the presence of ATP, ribokinase, PRPP-synthetase, and APR-transferase.

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...

TOPICAL REVIEW: Protein stability and enzyme activity at extreme biological temperatures

Science.gov (United States)

Feller, Georges

2010-08-01

Psychrophilic microorganisms thrive in permanently cold environments, even at subzero temperatures. To maintain metabolic rates compatible with sustained life, they have improved the dynamics of their protein structures, thereby enabling appropriate molecular motions required for biological activity at low temperatures. As a consequence of this structural flexibility, psychrophilic proteins are unstable and heat-labile. In the upper range of biological temperatures, thermophiles and hyperthermophiles grow at temperatures > 100 °C and synthesize ultra-stable proteins. However, thermophilic enzymes are nearly inactive at room temperature as a result of their compactness and rigidity. At the molecular level, both types of extremophilic proteins have adapted the same structural factors, but in opposite directions, to address either activity at low temperatures or stability in hot environments. A model based on folding funnels is proposed accounting for the stability-activity relationships in extremophilic proteins.

A new thermophilic nitrilase from an antarctic hyperthermophilic microorganism.

Directory of Open Access Journals (Sweden)

Geraldine V. Dennett

2016-02-01

Full Text Available Several environmental samples from Antarctica were collected and enriched to search for microorganisms with nitrilase activity. A new thermostable nitrilase from a novel hyperthermophilic archaea Pyrococcus sp. M24D13 was purified and characterized. The activity of this enzyme increased as the temperatures rise from 70 up to 85 °C. Its optimal activity occurred at 85 °C and pH 7.5. This new enzyme shows a remarkable resistance to thermal inactivation retaining more than 50% of its activity even after 8 h of incubation at 85 °C.In addition, this nitrilase is highly versatile demonstrating activity towards different substrates such as benzonitrile (60 mM, aromatic nitrile and butyronitrile (60 mM, aliphatic nitrile, with a specific activity of 3286.7 U mg-1 of protein and 4008.2 U mg-1 of protein respectively. Moreover the enzyme NitM24D13 also presents cyanidase activity.The apparent Michaelis-Menten constant (Km and Vmáx of this Nitrilase for benzonitrile were 0.3 mM and 333.3 µM min-1, respectively, and the specificity constant (kcat/Km for benzonitrile was 2.05×105 s-1 M-1.

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.

SCREENING OF THERMOPHYLIC MICROORGANISM FROM IJEN CRATER BANYUWANGI AS PHYTASE ENZYME PRODUCER

Directory of Open Access Journals (Sweden)

Aline Puspita Kusumadjaja

2010-06-01

Full Text Available Phytase is enzyme which hydrolysis phytic acid to anorganic phosphate and myo-inositol pentakis-, tetrakis-, tris-, bis-, and monophosphate. The use of phytase in feed industry can overcome environment and nutrition problems which were arisen from unmetabolism phytic acid or its salt by poultry, swine and fish. The feed industry needs a thermostable enzyme due to the need of high temperature in pelleting process, i.e. 81 °C. By using thermostabile phytase, the pelleting process will not affect the enzyme activity. Thermostabile phytase can be isolated from microorganism live in hot spring water or volcano crater. In this study, the screening of thermophylic microorganism having thermostabile phytase activity in Ijen Crater, Banyuwangi, has been done. From this process, it was obtained 33 isolates that produce phytase enzyme. Isolate was code by AP-17 yields highest phytase activity, that is 0.0296 U/mL, so this isolate was choosen for further study. The activity of crude phytase enzyme was measured based on the amount of anorganic phosphate that was produced in enzymatic reaction using UV-VIS spectrophotometer at 392 nm. Based on morphology test to identify the gram type of microorganism, isolate AP-17 has a bacill cell type and identified as positive gram bacteria. This isolate was assumed as Bacillus type.   Keywords: Phytase, thermophilic microorganism, phytase activity

Bioleaching of pollymetallic sulphide concentrate using thermophilic bacteria

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Vuković Milovan

2014-01-01

Full Text Available An extreme thermophilic, iron-sulphur oxidising bacterial culture was isolated and adapted to tolerate high metal and solids concentrations at 70°C. Following isolation and adaptation, the culture was used in a batch bioleach test employing a 5-l glass standard magnetic agitated and aerated reactor, for the bioleaching of a copper-lead-zinc collective concentrate. The culture exhibited stable leach performance over the period of leach operation and overall copper and zinc extractions higher than 97%. Lead sulphide is transformed into lead sulphate remaining in the bioleach residue due to the low solubility in sulphate media. Brine leaching of bioleach residue yields 95% lead extraction. [Projekat Ministarstva nauke Republike Srbije, br. 34023

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

Stable acetate production in extreme-thermophilic (70°C) mixed culture fermentation by selective enrichment of hydrogenotrophic methanogens

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Zhang, Fang; Zhang, Yan; Ding, Jing; Dai, Kun; van Loosdrecht, Mark C. M.; Zeng, Raymond J.

2014-06-01

The control of metabolite production is difficult in mixed culture fermentation. This is particularly related to hydrogen inhibition. In this work, hydrogenotrophic methanogens were selectively enriched to reduce the hydrogen partial pressure and to realize efficient acetate production in extreme-thermophilic (70°C) mixed culture fermentation. The continuous stirred tank reactor (CSTR) was stable operated during 100 days, in which acetate accounted for more than 90% of metabolites in liquid solutions. The yields of acetate, methane and biomass in CSTR were 1.5 +/- 0.06, 1.0 +/- 0.13 and 0.4 +/- 0.05 mol/mol glucose, respectively, close to the theoretical expected values. The CSTR effluent was stable and no further conversion occurred when incubated for 14 days in a batch reactor. In fed-batch experiments, acetate could be produced up to 34.4 g/L, significantly higher than observed in common hydrogen producing fermentations. Acetate also accounted for more than 90% of soluble products formed in these fed-batch fermentations. The microbial community analysis revealed hydrogenotrophic methanogens (mainly Methanothermobacter thermautotrophicus and Methanobacterium thermoaggregans) as 98% of Archaea, confirming that high temperature will select hydrogenotrophic methanogens over aceticlastic methanogens effectively. This work demonstrated a potential application to effectively produce acetate as a value chemical and methane as an energy gas together via mixed culture fermentation.

Biohydrogen production from untreated and hydrolyzed potato steam peels by the extreme thermophiles Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana

Energy Technology Data Exchange (ETDEWEB)

Mars, Astrid E.; Veuskens, Teun; Budde, Miriam A.W.; van Doeveren, Patrick F.N.M.; Lips, Steef J.; Bakker, Robert R.; de Vrije, Truus; Claassen, Pieternel A.M. [Wageningen UR, Food and Biobased Research, P.O. Box 17, 6700 AA Wageningen (Netherlands)

2010-08-15

Production of hydrogen by the extreme thermophiles Caldicellulosiruptor saccharolyticus and Thermotoga neapolitana was studied in serum flasks and in pH-controlled bioreactors with glucose, and hydrolyzed and untreated potato steam peels (PSP) as carbon sources. Two types of PSP hydrolysates were used: one in which the starch in the PSP was liquefied with alpha-amylase, and one in which the liquefied starch was further hydrolyzed to glucose by amyloglucosidase. When the PSP hydrolysates or untreated PSP were added at circa 10-14 g/L of glucose units, both strains grew well and produced hydrogen with reasonable to high molar yields (2.4-3.8 moles H{sub 2}/mole glucose units), and no significant production of lactate. The hydrogen production rates and yields were similar with untreated PSP, hydrolyzed PSP, and pure glucose, showing that C. saccharolyticus and T. neapolitana are well equipped for the utilization of starch. When the concentrations of the substrates were increased, growth and hydrogen production of both strains were hampered. At substrate concentrations of circa 30-40 g/L of glucose units, the molar hydrogen yield of C. saccharolyticus was severely reduced due to the formation of high amounts of lactate, while T. neapolitana was unable to grow at all. The results showed that PSP and PSP hydrolysates are very suitable substrates for efficient fermentative hydrogen production at moderate substrate loadings. (author)

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

International Nuclear Information System (INIS)

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

2012-01-01

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

Optimization of bioethanol production from carbohydrate rich wastes by extreme thermophilic microorganisms

DEFF Research Database (Denmark)

Tomás, Ana Faria

of the carbohydrates present in these complex substrates into ethanol. This is in particular true for pentose sugars such as xylose, generally the second major sugar present in lignocellulosic biomass. The transition of second-generation bioethanol production from pilot to industrial scale is hindered...... on the sugar composition of the rapeseed straw. This was 50 % and 14 % higher than the yield obtained with the bacteria or the yeast alone, respectively. When T. pentosaceus was immobilized in rapeseed straw, an improvement of 11 % in ethanol production was observed in batch mode. In continuous mode......, it was shown that hydraulic retention time (HRT) affected ethanol yield, and a dramatic shift from ethanol to acetate and lactate production occurred at an HRT of 6 h. The maximum ethanol yield and concentration, 1.50 mol mol-1 consumed sugars and 12.4 g l-1, were obtained with an HRT of 12 h. The latter...

Cellulases from Thermophilic Fungi: Recent Insights and Biotechnological Potential

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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.

Toxicity of fluoride to microorganisms in biological wastewater treatment systems.

Science.gov (United States)

Ochoa-Herrera, Valeria; Banihani, Qais; León, Glendy; Khatri, Chandra; Field, James A; Sierra-Alvarez, Reyes

2009-07-01

Fluoride is a common contaminant in a variety of industrial wastewaters. Available information on the potential toxicity of fluoride to microorganisms implicated in biological wastewater treatment is very limited. The objective of this study was to evaluate the inhibitory effect of fluoride towards the main microbial populations responsible for the removal of organic constituents and nutrients in wastewater treatment processes. The results of short-term batch bioassays indicated that the toxicity of sodium fluoride varied widely depending on the microbial population. Anaerobic microorganisms involved in various metabolic steps of anaerobic digestion processes were found to be very sensitive to the presence of fluoride. The concentrations of fluoride causing 50% metabolic inhibition (IC(50)) of propionate- and butyrate-degrading microorganisms as well as mesophilic and thermophilic acetate-utilizing methanogens ranged from 18 to 43 mg/L. Fluoride was also inhibitory to nitrification, albeit at relatively high levels (IC(50)=149 mg/L). Nitrifying bacteria appeared to adapt rapidly to fluoride, and a near complete recovery of their metabolic activity was observed after only 4d of exposure to high fluoride levels (up to 500 mg/L). All other microbial populations evaluated in this study, i.e., glucose fermenters, aerobic glucose-degrading heterotrophs, denitrifying bacteria, and H(2)-utilizing methanogens, tolerated fluoride at very high concentrations (>500 mg/L).

Cellular Viscosity in Prokaryotes and Thermal Stability of Low Molecular Weight Biomolecules.

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Cuecas, Alba; Cruces, Jorge; Galisteo-López, Juan F; Peng, Xiaojun; Gonzalez, Juan M

2016-08-23

Some low molecular weight biomolecules, i.e., NAD(P)H, are unstable at high temperatures. The use of these biomolecules by thermophilic microorganisms has been scarcely analyzed. Herein, NADH stability has been studied at different temperatures and viscosities. NADH decay increased at increasing temperatures. At increasing viscosities, NADH decay rates decreased. Thus, maintaining relatively high cellular viscosity in cells could result in increased stability of low molecular weight biomolecules (i.e., NADH) at high temperatures, unlike what was previously deduced from studies in diluted water solutions. Cellular viscosity was determined using a fluorescent molecular rotor in various prokaryotes covering the range from 10 to 100°C. Some mesophiles showed the capability of changing cellular viscosity depending on growth temperature. Thermophiles and extreme thermophiles presented a relatively high cellular viscosity, suggesting this strategy as a reasonable mechanism to thrive under these high temperatures. Results substantiate the capability of thermophiles and extreme thermophiles (growth range 50-80°C) to stabilize and use generally considered unstable, universal low molecular weight biomolecules. In addition, this study represents a first report, to our knowledge, on cellular viscosity measurements in prokaryotes and it shows the dependency of prokaryotic cellular viscosity on species and growth temperature. Copyright © 2016 Biophysical Society. Published by Elsevier Inc. All rights reserved.

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 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...

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.

Expression of a Recombinant Anti-HIV and Anti-Tumor Protein, MAP30, in Nicotiana tobacum Hairy Roots: A pH-Stable and Thermophilic Antimicrobial Protein.

Directory of Open Access Journals (Sweden)

Ali Moghadam

Full Text Available In contrast to conventional antibiotics, which microorganisms can readily evade, it is nearly impossible for a microbial strain that is sensitive to antimicrobial proteins to convert to a resistant strain. Therefore, antimicrobial proteins and peptides that are promising alternative candidates for the control of bacterial infections are under investigation. The MAP30 protein of Momordica charantia is a valuable type I ribosome-inactivating protein (RIP with anti-HIV and anti-tumor activities. Whereas the antimicrobial activity of some type I RIPs has been confirmed, less attention has been paid to the antimicrobial activity of MAP30 produced in a stable, easily handled, and extremely cost-effective protein-expression system. rMAP30-KDEL was expressed in Nicotiana tobacum hairy roots, and its effect on different microorganisms was investigated. Analysis of the extracted total proteins of transgenic hairy roots showed that rMAP30-KDEL was expressed effectively and that this protein exhibited significant antibacterial activity in a dose-dependent manner. rMAP30-KDEL also possessed thermal and pH stability. Bioinformatic analysis of MAP30 and other RIPs regarding their conserved motifs, amino-acid contents, charge, aliphatic index, GRAVY value, and secondary structures demonstrated that these factors accounted for their thermophilicity. Therefore, RIPs such as MAP30 and its derived peptides might have promising applications as food preservatives, and their analysis might provide useful insights into designing clinically applicable antibiotic agents.

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.

Surface (glyco-)proteins: primary structure and crystallization under microgravity conditions

Science.gov (United States)

Claus, H.; Akca, E.; Schultz, N.; Karbach, G.; Schlott, B.; Debaerdemaeker, T.; De Clercq, J.-P.; König, H.

2001-08-01

The Archaea comprise microorganisms that live under environmental extremes, like high temperature, low pH value or high salt concentration. Their cells are often covered by a single layer of (glyco)protein subunits (S-layer) in hexagonal arrangement. In order to get further hints about the molecular mechanisms of protein stabilization we compared the primary and secondary structures of archaeal S-layer (glyco)proteins. We found an increase of charged amino acids in the S-layer proteins of the extreme thermophilic species compared to their mesophilic counterparts. Our data and those of other authors suggest that ionic interactions, e.g., salt bridges seem to be played a major role in protein stabilization at high temperatures. Despite the differences in the growth optima and the predominance of some amino acids the primary structures of S-layers revealed also a significant degree of identity between phylogenetically related archaea. These obervations indicate that protein sequences of S-layers have been conserved during the evolution from extremely thermophilic to mesophilic life. To support these findings the three-dimensional structure of the S-layer proteins has to be elucidated. Recently, we described the first successful crystallization of an extreme thermophilic surface(glyco)protein under microgravity conditions.

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.

Comparative economic assessment of ethanol production under mesophilic and thermophilic conditions

International Nuclear Information System (INIS)

Mistry, P.B.

1991-01-01

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

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

KAUST Repository

Mohamed, Yasmine M.

2013-11-28

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

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

KAUST Repository

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

2013-01-01

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

Cre/lox-based multiple markerless gene disruption in the genome of the extreme thermophile Thermus thermophilus.

Science.gov (United States)

Togawa, Yoichiro; Nunoshiba, Tatsuo; Hiratsu, Keiichiro

2018-02-01

Markerless gene-disruption technology is particularly useful for effective genetic analyses of Thermus thermophilus (T. thermophilus), which have a limited number of selectable markers. In an attempt to develop a novel system for the markerless disruption of genes in T. thermophilus, we applied a Cre/lox system to construct a triple gene disruptant. To achieve this, we constructed two genetic tools, a loxP-htk-loxP cassette and cre-expressing plasmid, pSH-Cre, for gene disruption and removal of the selectable marker by Cre-mediated recombination. We found that the Cre/lox system was compatible with the proliferation of the T. thermophilus HB27 strain at the lowest growth temperature (50 °C), and thus succeeded in establishing a triple gene disruptant, the (∆TTC1454::loxP, ∆TTC1535KpnI::loxP, ∆TTC1576::loxP) strain, without leaving behind a selectable marker. During the process of the sequential disruption of multiple genes, we observed the undesired deletion and inversion of the chromosomal region between multiple loxP sites that were induced by Cre-mediated recombination. Therefore, we examined the effects of a lox66-htk-lox71 cassette by exploiting the mutant lox sites, lox66 and lox71, instead of native loxP sites. We successfully constructed a (∆TTC1535::lox72, ∆TTC1537::lox72) double gene disruptant without inducing the undesired deletion of the 0.7-kbp region between the two directly oriented lox72 sites created by the Cre-mediated recombination of the lox66-htk-lox71 cassette. This is the first demonstration of a Cre/lox system being applicable to extreme thermophiles in a genetic manipulation. Our results indicate that this system is a powerful tool for multiple markerless gene disruption in T. thermophilus.

Cellulolytic potential of thermophilic species from four fungal orders

DEFF Research Database (Denmark)

Busk, Peter Kamp; Lange, Lene

2013-01-01

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

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

Thermophilic Fungi: Their Physiology and Enzymes†

OpenAIRE

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

2000-01-01

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

Thermophillic Sidestream Anaerobic Membrane Bioreactors: The Shear Rate Dilemma

NARCIS (Netherlands)

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

2009-01-01

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

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

Science.gov (United States)

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

2013-04-01

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

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

Directory of Open Access Journals (Sweden)

Chia Sing eChan

2015-03-01

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

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...

A robust nitrifying community in a bioreactor at 50 °C opens up the path for thermophilic nitrogen removal.

Science.gov (United States)

Courtens, Emilie Np; Spieck, Eva; Vilchez-Vargas, Ramiro; Bodé, Samuel; Boeckx, Pascal; Schouten, Stefan; Jauregui, Ruy; Pieper, Dietmar H; Vlaeminck, Siegfried E; Boon, Nico

2016-09-01

The increasing production of nitrogen-containing fertilizers is crucial to meet the global food demand, yet high losses of reactive nitrogen associated with the food production/consumption chain progressively deteriorate the natural environment. Currently, mesophilic nitrogen-removing microbes eliminate nitrogen from wastewaters. Although thermophilic nitrifiers have been separately enriched from natural environments, no bioreactors are described that couple these processes for the treatment of nitrogen in hot wastewaters. Samples from composting facilities were used as inoculum for the batch-wise enrichment of thermophilic nitrifiers (350 days). Subsequently, the enrichments were transferred to a bioreactor to obtain a stable, high-rate nitrifying process (560 days). The community contained up to 17% ammonia-oxidizing archaea (AOAs) closely related to 'Candidatus Nitrososphaera gargensis', and 25% nitrite-oxidizing bacteria (NOBs) related to Nitrospira calida. Incorporation of (13)C-derived bicarbonate into the respective characteristic membrane lipids during nitrification supported their activity as autotrophs. Specific activities up to 198±10 and 894±81 mg N g(-1) VSS per day for AOAs and NOBs were measured, where NOBs were 33% more sensitive to free ammonia. The NOBs were extremely sensitive to free nitrous acid, whereas the AOAs could only be inhibited by high nitrite concentrations, independent of the free nitrous acid concentration. The observed difference in product/substrate inhibition could facilitate the development of NOB inhibition strategies to achieve more cost-effective processes such as deammonification. This study describes the enrichment of autotrophic thermophilic nitrifiers from a nutrient-rich environment and the successful operation of a thermophilic nitrifying bioreactor for the first time, facilitating opportunities for thermophilic nitrogen removal biotechnology.

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

Energy Technology Data Exchange (ETDEWEB)

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

2009-03-15

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

Copper extraction from coarsely ground printed circuit boards using moderate thermophilic bacteria in a rotating-drum reactor

Energy Technology Data Exchange (ETDEWEB)

Rodrigues, Michael L.M., E-mail: mitchel.marques@yahoo.com.br [Bio& Hydrometallurgy Laboratory, Department of Metallurgical and Materials Engineering, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, Ouro Preto, MG 35400-000 (Brazil); Leão, Versiane A., E-mail: versiane@demet.em.ufop.br [Bio& Hydrometallurgy Laboratory, Department of Metallurgical and Materials Engineering, Universidade Federal de Ouro Preto, Campus Morro do Cruzeiro, Ouro Preto, MG 35400-000 (Brazil); Gomes, Otavio [Centre for Mineral Technology – CETEM, Av Pedro Calmon, 900, 21941-908 Rio de Janeiro (Brazil); Lambert, Fanny; Bastin, David; Gaydardzhiev, Stoyan [Mineral Processing and Recycling, University of Liege, SartTilman, 4000 Liege (Belgium)

2015-07-15

Highlights: • Copper bioleaching from PCB (20 mm) by moderate thermophiles was demonstrated. • Larger PCB sheets enable a cost reduction due to the elimination of fine grinding. • Crushing generated cracks in PCB increasing the copper extraction. • A pre-treatment step was necessary to remove the lacquer coating. • High copper extractions (85%) were possible with pulp density of up to 25.0 g/L. - Abstract: The current work reports on a new approach for copper bioleaching from Printed Circuit Board (PCB) by moderate thermophiles in a rotating-drum reactor. Initially leaching of PCB was carried out in shake flasks to assess the effects of particle size (−208 μm + 147 μm), ferrous iron concentration (1.25–10.0 g/L) and pH (1.5–2.5) on copper leaching using mesophile and moderate thermophile microorganisms. Only at a relatively low solid content (10.0 g/L) complete copper extraction was achieved from the particle size investigated. Conversely, high copper extractions were possible from coarse-ground PCB (20 mm-long) working with increased solids concentration (up to 25.0 g/L). Because there was as the faster leaching kinetics at 50 °C Sulfobacillus thermosulfidooxidans was selected for experiments in a rotating-drum reactor with the coarser-sized PCB sheets. Under optimal conditions, copper extraction reached 85%, in 8 days and microscopic observations by SEM–EDS of the on non-leached and leached material suggested that metal dissolution from the internal layers was restricted by the fact that metal surface was not entirely available and accessible for the solution in the case of the 20 mm-size sheets.

Copper extraction from coarsely ground printed circuit boards using moderate thermophilic bacteria in a rotating-drum reactor

International Nuclear Information System (INIS)

Rodrigues, Michael L.M.; Leão, Versiane A.; Gomes, Otavio; Lambert, Fanny; Bastin, David; Gaydardzhiev, Stoyan

2015-01-01

Highlights: • Copper bioleaching from PCB (20 mm) by moderate thermophiles was demonstrated. • Larger PCB sheets enable a cost reduction due to the elimination of fine grinding. • Crushing generated cracks in PCB increasing the copper extraction. • A pre-treatment step was necessary to remove the lacquer coating. • High copper extractions (85%) were possible with pulp density of up to 25.0 g/L. - Abstract: The current work reports on a new approach for copper bioleaching from Printed Circuit Board (PCB) by moderate thermophiles in a rotating-drum reactor. Initially leaching of PCB was carried out in shake flasks to assess the effects of particle size (−208 μm + 147 μm), ferrous iron concentration (1.25–10.0 g/L) and pH (1.5–2.5) on copper leaching using mesophile and moderate thermophile microorganisms. Only at a relatively low solid content (10.0 g/L) complete copper extraction was achieved from the particle size investigated. Conversely, high copper extractions were possible from coarse-ground PCB (20 mm-long) working with increased solids concentration (up to 25.0 g/L). Because there was as the faster leaching kinetics at 50 °C Sulfobacillus thermosulfidooxidans was selected for experiments in a rotating-drum reactor with the coarser-sized PCB sheets. Under optimal conditions, copper extraction reached 85%, in 8 days and microscopic observations by SEM–EDS of the on non-leached and leached material suggested that metal dissolution from the internal layers was restricted by the fact that metal surface was not entirely available and accessible for the solution in the case of the 20 mm-size sheets

Perspectives on biotechnological applications of archaea

Science.gov (United States)

Schiraldi, Chiara; Giuliano, Mariateresa; De Rosa, Mario

2002-01-01

Many archaea colonize extreme environments. They include hyperthermophiles, sulfur-metabolizing thermophiles, extreme halophiles and methanogens. Because extremophilic microorganisms have unusual properties, they are a potentially valuable resource in the development of novel biotechnological processes. Despite extensive research, however, there are few existing industrial applications of either archaeal biomass or archaeal enzymes. This review summarizes current knowledge about the biotechnological uses of archaea and archaeal enzymes with special attention to potential applications that are the subject of current experimental evaluation. Topics covered include cultivation methods, recent achievements in genomics, which are of key importance for the development of new biotechnological tools, and the application of wild-type biomasses, engineered microorganisms, enzymes and specific metabolites in particular bioprocesses of industrial interest. PMID:15803645

Assessment of cellulolytic microorganisms in soils of Nevados Park, Colombia.

Science.gov (United States)

Avellaneda-Torres, Lizeth Manuela; Pulido, Claudia Patricia Guevara; Rojas, Esperanza Torres

2014-01-01

A systematized survey was conducted to find soil-borne microbes that degrade cellulose in soils from unique ecosystems, such as the Superpáramo, Páramo, and the High Andean Forest in the Nevados National Natural Park (NNNP), Colombia. These high mountain ecosystems represent extreme environments, such as high levels of solar radiation, low atmospheric pressure, and extreme daily changes in temperature. Cellulolytic activity of the microorganisms was evaluated using qualitative tests, such as growth in selective media followed by staining with congo red and iodine, and quantitative tests to determine the activity of endoglucanase, β-glucosidase, exoglucanase, and total cellulase. Microorganisms were identified using molecular markers, such as the 16S rRNA gene for bacteria and the internal transcribed spacer region (ITS) of ribosomal DNA for fungi. Multivariate statistical analysis (MVA) was used to select microorganisms with high cellulolytic capacity. A total of 108 microorganisms were isolated from the soils and, in general, the enzymatic activities of fungi were higher than those of bacteria. Our results also found that none of the organisms studied were able to degrade all the components of the cellulose and it is therefore suggested that a combination of bacteria and/or fungi with various enzymatic activities be used to obtain high total cellulolytic activity. This study gives an overview of the potential microorganism that could be used for cellulose degradation in various biotechnological applications and for sustainable agricultural waste treatment.

Assessment of cellulolytic microorganisms in soils of Nevados Park, Colombia

Directory of Open Access Journals (Sweden)

Lizeth Manuela Avellaneda-Torres

2014-12-01

Full Text Available A systematized survey was conducted to find soil-borne microbes that degrade cellulose in soils from unique ecosystems, such as the Superpáramo, Páramo, and the High Andean Forest in the Nevados National Natural Park (NNNP, Colombia. These high mountain ecosystems represent extreme environments, such as high levels of solar radiation, low atmospheric pressure, and extreme daily changes in temperature. Cellulolytic activity of the microorganisms was evaluated using qualitative tests, such as growth in selective media followed by staining with congo red and iodine, and quantitative tests to determine the activity of endoglucanase, β-glucosidase, exoglucanase, and total cellulase. Microorganisms were identified using molecular markers, such as the 16S rRNA gene for bacteria and the internal transcribed spacer region (ITS of ribosomal DNA for fungi. Multivariate statistical analysis (MVA was used to select microorganisms with high cellulolytic capacity. A total of 108 microorganisms were isolated from the soils and, in general, the enzymatic activities of fungi were higher than those of bacteria. Our results also found that none of the organisms studied were able to degrade all the components of the cellulose and it is therefore suggested that a combination of bacteria and/or fungi with various enzymatic activities be used to obtain high total cellulolytic activity. This study gives an overview of the potential microorganism that could be used for cellulose degradation in various biotechnological applications and for sustainable agricultural waste treatment.

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

Science.gov (United States)

Chen, Shen-Yi; Chou, Li-Chieh

2016-08-01

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

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

Science.gov (United States)

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

2016-01-01

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

Novel Industrial Enzymes from Uncultured Arctic Microorganisms

DEFF Research Database (Denmark)

Vester, Jan Kjølhede

, and reduce the risk of contaminations. Cold- and alkaline-active enzymes can be found in microorganisms adapted to living in natural environments with these conditions, which are extremely rare but found in the unique ikaite columns from SW Greenland (4-6 °C, pH >10). It is estimated that less than 1...

Comparison of the thermostability of cellulases from various thermophilic fungi

Energy Technology Data Exchange (ETDEWEB)

Wojtczak, G; Breuil, C; Yamada, J; Saddler, J N

1987-10-01

The cellulase activities of six thermophilic fungi were compared. Although the thermophilic fungi grew at relatively high temperatures (> 45/sup 0/C) the optimum temperatures for assaying the various cellulase activities were only slightly higher than the optimum temperatures for the mesophilic fungi, Trichoderma harzianum. Over prolonged incubation (> 24 h) the thermophilic strains demonstrated a higher hydrolytic potential as a result of the greater thermostability of the cellulase components. Although the extracellular cellulase activities had similar pH and temperature optima, in some cases the thermostability of the extracellular components were considerably lower.

Diversity of thermophilic bacteria in raw, pasteurized and selectively-cultured milk, as assessed by culturing, PCR-DGGE and pyrosequencing.

Science.gov (United States)

Delgado, Susana; Rachid, Caio T C C; Fernández, Elena; Rychlik, Tomasz; Alegría, Angel; Peixoto, Raquel S; Mayo, Baltasar

2013-10-01

Thermophilic lactic acid bacteria (LAB) species, such as Streptococcus thermophilus, Lactobacillus delbrueckii and Lactobacillus helveticus, enjoy worldwide economic importance as dairy starters. To assess the diversity of thermophilic bacteria in milk, milk samples were enriched in thermophilic organisms through a stepwise procedure which included pasteurization of milk at 63 °C for 30 min (PM samples) and pasteurization followed by incubation at 42 °C for 24 h (IPM samples). The microbial composition of these samples was analyzed by culture-dependent (at 42 °C) and culture-independent (PCR-DGGE and pyrosequencing of 16S rRNA gene amplicons) microbial techniques. The results were then compared to those obtained for their corresponding starting raw milk counterparts (RM samples). Twenty different species were scored by culturing among 352 isolates purified from the counting plates and identified by molecular methods. Mesophilic LAB species (Lactococcus lactis, Lactococcus garvieae) were dominant (87% of the isolates) among the RM samples. However, S. thermophilus and Lb. delbrueckii were found to be the dominant recoverable organisms in both PM and IPM samples. The DGGE profiles of RM and PM samples were found to be very similar; the most prominent bands belonging to Lactococcus, Leuconostoc and Streptococcus species. In contrast, just three DGGE bands were obtained for IPM samples, two of which were assigned to S. thermophilus. The pyrosequencing results scored 95 operational taxonomic units (OTUs) at 3% sequence divergence in an RM sample, while only 13 were encountered in two IPM samples. This technique identified Leuconostoc citreum as the dominant microorganism in the RM sample, while S. thermophilus constituted more than 98% of the reads in the IPM samples. The procedure followed in this study allowed to estimate the bacterial diversity in milk and afford a suitable strategy for the isolation of new thermophilic LAB strains, among which adequate

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

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

Science.gov (United States)

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

2018-04-12

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

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

Directory of Open Access Journals (Sweden)

Mohamed Amine Gomri

2018-04-01

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

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....

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

Directory of Open Access Journals (Sweden)

Deanne W Sammond

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

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.

Thermophilic growth and enzymatic thermostability are polyphyletic traits within Chaetomiaceae.

Science.gov (United States)

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

2015-12-01

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

Biomass production and energy source of thermophiles in a Japanese alkaline geothermal pool.

Science.gov (United States)

Kimura, Hiroyuki; Mori, Kousuke; Nashimoto, Hiroaki; Hattori, Shohei; Yamada, Keita; Koba, Keisuke; Yoshida, Naohiro; Kato, Kenji

2010-02-01

Microbial biomass production has been measured to investigate the contribution of planktonic bacteria to fluxations in dissolved organic matter in marine and freshwater environments, but little is known about biomass production of thermophiles inhabiting geothermal and hydrothermal regions. The biomass production of thermophiles inhabiting an 85 degrees C geothermal pool was measured by in situ cultivation using diffusion chambers. The thermophiles' growth rates ranged from 0.43 to 0.82 day(-1), similar to those of planktonic bacteria in marine and freshwater habitats. Biomass production was estimated based on cellular carbon content measured directly from the thermophiles inhabiting the geothermal pool, which ranged from 5.0 to 6.1 microg C l(-1) h(-1). This production was 2-75 times higher than that of planktonic bacteria in other habitats, because the cellular carbon content of the thermophiles was much higher. Quantitative PCR and phylogenetic analysis targeting 16S rRNA genes revealed that thermophilic H2-oxidizing bacteria closely related to Calderobacterium and Geothermobacterium were dominant in the geothermal pool. Chemical analysis showed the presence of H2 in gases bubbling from the bottom of the geothermal pool. These results strongly suggested that H2 plays an important role as a primary energy source of thermophiles in the geothermal pool.

Saline-water bioleaching of chalcopyrite with thermophilic, iron(II)- and sulfur-oxidizing microorganisms.

Science.gov (United States)

Watling, Helen R; Collinson, David M; Corbett, Melissa K; Shiers, Denis W; Kaksonen, Anna H; Watkin, Elizabeth L J

2016-09-01

The application of thermoacidophiles for chalcopyrite (CuFeS2) bioleaching in hot, acidic, saline solution was investigated as a possible process route for rapid Cu extraction. The study comprised a discussion of protective mechanisms employed for the survival and/or adaptation of thermoacidophiles to osmotic stress, a compilation of chloride tolerances for three genera of thermoacidophiles applied in bioleaching and an experimental study of the activities of three species in a saline bioleaching system. The data showed that the oxidation rates of iron(II) and reduced inorganic sulfur compounds (tetrathionate) were reduced in the presence of chloride levels well below chloride concentrations in seawater, limiting the applicability of these microorganisms in the bioleaching of CuFeS2 in saline water. Copyright © 2016. Published by Elsevier Masson SAS.

Diversity of thermophilic archaeal isolates from hot springs in Japan

Science.gov (United States)

Itoh, Takashi; Yoshikawa, Naoto; Takashina, Tomonori

2005-09-01

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

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.

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

Science.gov (United States)

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

2007-08-15

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

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

Force-dependent melting of supercoiled DNA at thermophilic temperatures.

Science.gov (United States)

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

2014-01-01

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

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

Science.gov (United States)

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

2013-09-01

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

Complete genome sequence of the aerobic CO-oxidizing thermophile Thermomicrobium roseum.

Directory of Open Access Journals (Sweden)

Dongying Wu

Full Text Available In order to enrich the phylogenetic diversity represented in the available sequenced bacterial genomes and as part of an "Assembling the Tree of Life" project, we determined the genome sequence of Thermomicrobium roseum DSM 5159. T. roseum DSM 5159 is a red-pigmented, rod-shaped, Gram-negative extreme thermophile isolated from a hot spring that possesses both an atypical cell wall composition and an unusual cell membrane that is composed entirely of long-chain 1,2-diols. Its genome is composed of two circular DNA elements, one of 2,006,217 bp (referred to as the chromosome and one of 919,596 bp (referred to as the megaplasmid. Strikingly, though few standard housekeeping genes are found on the megaplasmid, it does encode a complete system for chemotaxis including both chemosensory components and an entire flagellar apparatus. This is the first known example of a complete flagellar system being encoded on a plasmid and suggests a straightforward means for lateral transfer of flagellum-based motility. Phylogenomic analyses support the recent rRNA-based analyses that led to T. roseum being removed from the phylum Thermomicrobia and assigned to the phylum Chloroflexi. Because T. roseum is a deep-branching member of this phylum, analysis of its genome provides insights into the evolution of the Chloroflexi. In addition, even though this species is not photosynthetic, analysis of the genome provides some insight into the origins of photosynthesis in the Chloroflexi. Metabolic pathway reconstructions and experimental studies revealed new aspects of the biology of this species. For example, we present evidence that T. roseum oxidizes CO aerobically, making it the first thermophile known to do so. In addition, we propose that glycosylation of its carotenoids plays a crucial role in the adaptation of the cell membrane to this bacterium's thermophilic lifestyle. Analyses of published metagenomic sequences from two hot springs similar to the one from which

Assessment of cellulolytic microorganisms in soils of Nevados Park, Colombia

OpenAIRE

Avellaneda-Torres,Lizeth Manuela; Pulido,Claudia Patricia Guevara; Rojas,Esperanza Torres

2014-01-01

A systematized survey was conducted to find soil-borne microbes that degrade cellulose in soils from unique ecosystems, such as the Superpáramo, Páramo, and the High Andean Forest in the Nevados National Natural Park (NNNP), Colombia. These high mountain ecosystems represent extreme environments, such as high levels of solar radiation, low atmospheric pressure, and extreme daily changes in temperature. Cellulolytic activity of the microorganisms was evaluated using qualitative tests, such as ...

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

Energy Technology Data Exchange (ETDEWEB)

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

1986-01-01

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

Gold nanoparticles synthesized by Geobacillus sp. strain ID17 a thermophilic bacterium isolated from Deception Island, Antarctica

Science.gov (United States)

2013-01-01

Background The use of microorganisms in the synthesis of nanoparticles emerges as an eco-friendly and exciting approach, for production of nanoparticles due to its low energy requirement, environmental compatibility, reduced costs of manufacture, scalability, and nanoparticle stabilization compared with the chemical synthesis. Results The production of gold nanoparticles by the thermophilic bacterium Geobacillus sp. strain ID17 is reported in this study. Cells exposed to Au3+ turned from colourless into an intense purple colour. This change of colour indicates the accumulation of intracellular gold nanoparticles. Elemental analysis of particles composition was verified using TEM and EDX analysis. The intracellular localization and particles size were verified by TEM showing two different types of particles of predominant quasi-hexagonal shape with size ranging from 5–50 nm. The mayority of them were between 10‒20 nm in size. FT-IR was utilized to characterize the chemical surface of gold nanoparticles. This assay supports the idea of a protein type of compound on the surface of biosynthesized gold nanoparticles. Reductase activity involved in the synthesis of gold nanoparticles has been previously reported to be present in others microorganisms. This reduction using NADH as substrate was tested in ID17. Crude extracts of the microorganism could catalyze the NADH-dependent Au3+ reduction. Conclusions Our results strongly suggest that the biosynthesis of gold nanoparticles by ID17 is mediated by enzymes and NADH as a cofactor for this biological transformation. PMID:23919572

A Genetic System for the Thermophilic Acetogenic Bacterium Thermoanaerobacter kivui.

Science.gov (United States)

Basen, Mirko; Geiger, Irina; Henke, Laura; Müller, Volker

2018-02-01

Thermoanaerobacter kivui is one of the very few thermophilic acetogenic microorganisms. It grows optimally at 66°C on sugars but also lithotrophically with H 2 + CO 2 or with CO, producing acetate as the major product. While a genome-derived model of acetogenesis has been developed, only a few physiological or biochemical experiments regarding the function of important enzymes in carbon and energy metabolism have been carried out. To address this issue, we developed a method for targeted markerless gene deletions and for integration of genes into the genome of T. kivui The strain naturally took up plasmid DNA in the exponential growth phase, with a transformation frequency of up to 3.9 × 10 -6 A nonreplicating plasmid and selection with 5-fluoroorotate was used to delete the gene encoding the orotate phosphoribosyltransferase ( pyrE ), resulting in a Δ pyrE uracil-auxotrophic strain, TKV002. Reintroduction of pyrE on a plasmid or insertion of pyrE into different loci within the genome restored growth without uracil. We subsequently studied fructose metabolism in T. kivui The gene fruK (TKV_c23150) encoding 1-phosphofructosekinase (1-PFK) was deleted, using pyrE as a selective marker via two single homologous recombination events. The resulting Δ fruK strain, TKV003, did not grow on fructose; however, growth on glucose (or on mannose) was unaffected. The combination of pyrE as a selective marker and the natural competence of the strain for DNA uptake will be the basis for future studies on CO 2 reduction and energy conservation and their regulation in this thermophilic acetogenic bacterium. IMPORTANCE Acetogenic bacteria are currently the focus of research toward biotechnological applications due to their potential for de novo synthesis of carbon compounds such as acetate, butyrate, or ethanol from H 2 + CO 2 or from synthesis gas. Based on available genome sequences and on biochemical experiments, acetogens differ in their energy metabolism. Thus, there is an

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

DEFF Research Database (Denmark)

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

2008-01-01

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

Life at extreme conditions: neutron scattering studies of biological molecules suggest that evolution selected dynamics

International Nuclear Information System (INIS)

Zaccai, Joseph Giuseppe

2008-01-01

The short review concentrates on recent work performed at the neutrons in biology laboratories of the Institut Laue Langevin and Institut de Biologie Structurale in Grenoble. Extremophile organisms have been discovered that require extreme conditions of temperature, pressure or solvent environment for survival. The existence of such organisms poses a significant challenge in understanding the physical chemistry of their proteins, in view of the great sensitivity of protein structure and stability to the aqueous environment and to external conditions in general. Results of neutron scattering measurements on the dynamics of proteins from extremophile organisms, in vitro as well as in vivo, indicated remarkably how adaptation to extreme conditions involves forces and fluctuation amplitudes that have been selected specifically, suggesting that evolutionary macromolecular selection proceeded via dynamics. The experiments were performed on a halophilic protein, and membrane adapted to high salt, a thermophilic enzyme adapted to high temperature and its mesophilic (adapted to 37 degC) homologue; and in vivo for psychrophilic, mesophilic, thermophilic and hyperthermophilic bacteria, adapted respectively to temperatures of 4 degC, 37 degC, 75 degC and 85 degC. Further work demonstrated the existence of a water component of exceptionally low mobility in an extreme halophile from the Dead Sea, which is not present in mesophile bacterial cells. (author)

Simultaneous production of acetate and methane from glycerol by selective enrichment of hydrogenotrophic methanogens in extreme-thermophilic (70 °C) mixed culture fermentation

International Nuclear Information System (INIS)

Zhang, Fang; Zhang, Yan; Chen, Yun; Dai, Kun; Loosdrecht, Mark C.M. van; Zeng, Raymond J.

2015-01-01

Highlights: • Simultaneous production of acetate and methane from glycerol was investigated. • Acetate accounted for more than 90% of metabolites in liquid solutions. • The maximum concentration of acetate was above 13 g/L. • 93% of archaea were hydrogenotrophic methanogens. • Thermoanaerobacter was main bacterium and its percentage was 92%. - Abstract: The feasibility of simultaneous production of acetate and methane from glycerol was investigated by selective enrichment of hydrogenotrophic methanogens in an extreme-thermophilic (70 °C) fermentation. Fed-batch experiments showed acetate was produced at the concentration up to 13.0 g/L. A stable operation of the continuous stirred tank reactor (CSTR) was reached within 100 days. Acetate accounted for more than 90 w/w% of metabolites in the fermentation liquid. The yields of methane and acetate were close to the theoretical yields with 0.74–0.80 mol-methane/mol-glycerol and 0.63–0.70 mol-acetate/mol-glycerol. The obtained microbial community was characterized. Hydrogenotrophic methanogens, mainly Methanothermobacter thermautotrophicus formed 93% of the methanogenogenic community. This confirms that a high temperature (70 °C) could effectively select for hydrogenotrophic methanogenic archaea. Thermoanaerobacter spp. was the main bacterium forming 91.5% of the bacterial population. This work demonstrated the conversion of the byproduct of biodiesel production, glycerol, to acetate as a chemical and biogas for energy generation

Experimental assessment of factors influencing dewatering properties of thermophilically digested biosolids

Energy Technology Data Exchange (ETDEWEB)

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

2003-07-01

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

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.

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

Science.gov (United States)

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

2014-09-01

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

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

Science.gov (United States)

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

2013-09-01

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

Removal of triazine herbicides from freshwater systems using photosynthetic microorganisms

International Nuclear Information System (INIS)

Gonzalez-Barreiro, O.; Rioboo, C.; Herrero, C.; Cid, A.

2006-01-01

The uptake of the triazine herbicides, atrazine and terbutryn, was determined for two freshwater photosynthetic microorganisms, the green microalga Chlorella vulgaris and the cyanobacterium Synechococcus elongatus. An extremely rapid uptake of both pesticides was recorded, although uptake rate was lower for the cyanobacterium, mainly for atrazine. Other parameters related to the herbicide bioconcentration capacity of these microorganisms were also studied. Growth rate, biomass, and cell viability in cultures containing herbicide were clearly affected by herbicide uptake. Herbicide toxicity and microalgae sensitivity were used to determine the effectiveness of the bioconcentration process and the stability of herbicide removal. C. vulgaris showed higher bioconcentration capability for these two triazine herbicides than S. elongatus, especially with regard to terbutryn. This study supports the usefulness of such microorganisms, as a bioremediation technique in freshwater systems polluted with triazine herbicides

Removal of triazine herbicides from freshwater systems using photosynthetic microorganisms

Energy Technology Data Exchange (ETDEWEB)

Gonzalez-Barreiro, O. [Laboratorio de Microbiologia, Facultad de Ciencias, Universidad de A Coruna, Campus da Zapateira s/n. 15071 A Coruna (Spain); Rioboo, C. [Laboratorio de Microbiologia, Facultad de Ciencias, Universidad de A Coruna, Campus da Zapateira s/n. 15071 A Coruna (Spain); Herrero, C. [Laboratorio de Microbiologia, Facultad de Ciencias, Universidad de A Coruna, Campus da Zapateira s/n. 15071 A Coruna (Spain); Cid, A. [Laboratorio de Microbiologia, Facultad de Ciencias, Universidad de A Coruna, Campus da Zapateira s/n. 15071 A Coruna (Spain)]. E-mail: cid@udc.es

2006-11-15

The uptake of the triazine herbicides, atrazine and terbutryn, was determined for two freshwater photosynthetic microorganisms, the green microalga Chlorella vulgaris and the cyanobacterium Synechococcus elongatus. An extremely rapid uptake of both pesticides was recorded, although uptake rate was lower for the cyanobacterium, mainly for atrazine. Other parameters related to the herbicide bioconcentration capacity of these microorganisms were also studied. Growth rate, biomass, and cell viability in cultures containing herbicide were clearly affected by herbicide uptake. Herbicide toxicity and microalgae sensitivity were used to determine the effectiveness of the bioconcentration process and the stability of herbicide removal. C. vulgaris showed higher bioconcentration capability for these two triazine herbicides than S. elongatus, especially with regard to terbutryn. This study supports the usefulness of such microorganisms, as a bioremediation technique in freshwater systems polluted with triazine herbicides.

Reduction of hexavalent chromium by the thermophilic methanogen Methanothermobacter thermautotrophicus

Science.gov (United States)

Singh, Rajesh; Dong, Hailiang; Liu, Deng; Zhao, Linduo; Marts, Amy R.; Farquhar, Erik; Tierney, David L.; Almquist, Catherine B.; Briggs, Brandon R.

2015-01-01

Despite significant progress on iron reduction by thermophilic microorganisms, studies on their ability to reduce toxic metals are still limited, despite their common co-existence in high temperature environments (up to 70 °C). In this study, Methanothermobacter thermautotrophicus, an obligate thermophilic methanogen, was used to reduce hexavalent chromium. Experiments were conducted in a growth medium with H2/CO2 as substrate with various Cr6+ concentrations (0.2, 0.4, 1, 3, and 5 mM) in the form of potassium dichromate (K2Cr2O7). Time-course measurements of aqueous Cr6+ concentrations using 1,5-diphenylcarbazide colorimetric method showed complete reduction of the 0.2 and 0.4 mM Cr6+ solutions by this methanogen. However, much lower reduction extents of 43.6%, 13.0%, and 3.7% were observed at higher Cr6+ concentrations of 1, 3 and 5 mM, respectively. These lower extents of bioreduction suggest a toxic effect of aqueous Cr6+ to cells at this concentration range. At these higher Cr6+ concentrations, methanogenesis was inhibited and cell growth was impaired as evidenced by decreased total cellular protein production and live/dead cell ratio. Likewise, Cr6+ bioreduction rates decreased with increased initial concentrations of Cr6+ from 13.3 to 1.9 μM h-1. X-ray absorption near-edge structure (XANES) spectroscopy revealed a progressive reduction of soluble Cr6+ to insoluble Cr3+ precipitates, which was confirmed as amorphous chromium hydroxide by selected area electron diffraction pattern. However, a small fraction of reduced Cr occurred as aqueous Cr3+. Scanning and transmission electron microscope observations of M. thermautotrophicus cells after Cr6+ exposure suggest both extra- and intracellular chromium reduction mechanisms. Results of this study demonstrate the ability of M. thermautotrophicus cells to reduce toxic Cr6+ to less toxic Cr3+ and its potential application in metal bioremediation, especially at high temperature subsurface radioactive waste disposal

Detoxification of biomass derived acetate via metabolic conversion to ethanol, acetone, isopropanol, or ethyl acetate

Science.gov (United States)

Sillers, William Ryan; Van Dijken, Hans; Licht, Steve; Shaw, IV, Arthur J.; Gilbert, Alan Benjamin; Argyros, Aaron; Froehlich, Allan C.; McBride, John E.; Xu, Haowen; Hogsett, David A.; Rajgarhia, Vineet B.

2017-03-28

One aspect of the invention relates to a genetically modified thermophilic or mesophilic microorganism, wherein a first native gene is partially, substantially, or completely deleted, silenced, inactivated, or down-regulated, which first native gene encodes a first native enzyme involved in the metabolic production of an organic acid or a salt thereof, thereby increasing the native ability of said thermophilic or mesophilic microorganism to produce lactate or acetate as a fermentation product. In certain embodiments, the aforementioned microorganism further comprises a first non-native gene, which first non-native gene encodes a first non-native enzyme involved in the metabolic production of lactate or acetate. Another aspect of the invention relates to a process for converting lignocellulosic biomass to lactate or acetate, comprising contacting lignocellulosic biomass with a genetically modified thermophilic or mesophilic microorganism.

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

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)

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

Energy Technology Data Exchange (ETDEWEB)

Margaritis, A; Merchant, R; Yaguchi, M

1983-01-01

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

Microorganism immobilization

Science.gov (United States)

Compere, Alicia L.; Griffith, William L.

1981-01-01

Live metabolically active microorganisms are immobilized on a solid support by contacting particles of aggregate material with a water dispersible polyelectrolyte such as gelatin, crosslinking the polyelectrolyte by reacting it with a crosslinking agent such as glutaraldehyde to provide a crosslinked coating on the particles of aggregate material, contacting the coated particles with live microorganisms and incubating the microorganisms in contact with the crosslinked coating to provide a coating of metabolically active microorganisms. The immobilized microorganisms have continued growth and reproduction functions.

Microbial enhanced heavy oil recovery by the aid of inhabitant spore-forming bacteria: an insight review.

Science.gov (United States)

Shibulal, Biji; Al-Bahry, Saif N; Al-Wahaibi, Yahya M; Elshafie, Abdulkader E; Al-Bemani, Ali S; Joshi, Sanket J

2014-01-01

Crude oil is the major source of energy worldwide being exploited as a source of economy, including Oman. As the price of crude oil increases and crude oil reserves collapse, exploitation of oil resources in mature reservoirs is essential for meeting future energy demands. As conventional recovery methods currently used have become less efficient for the needs, there is a continuous demand of developing a new technology which helps in the upgradation of heavy crude oil. Microbial enhanced oil recovery (MEOR) is an important tertiary oil recovery method which is cost-effective and eco-friendly technology to drive the residual oil trapped in the reservoirs. The potential of microorganisms to degrade heavy crude oil to reduce viscosity is considered to be very effective in MEOR. Earlier studies of MEOR (1950s) were based on three broad areas: injection, dispersion, and propagation of microorganisms in petroleum reservoirs; selective degradation of oil components to improve flow characteristics; and production of metabolites by microorganisms and their effects. Since thermophilic spore-forming bacteria can thrive in very extreme conditions in oil reservoirs, they are the most suitable organisms for the purpose. This paper contains the review of work done with thermophilic spore-forming bacteria by different researchers.

Microbial Enhanced Heavy Oil Recovery by the Aid of Inhabitant Spore-Forming Bacteria: An Insight Review

Directory of Open Access Journals (Sweden)

Biji Shibulal

2014-01-01

Full Text Available Crude oil is the major source of energy worldwide being exploited as a source of economy, including Oman. As the price of crude oil increases and crude oil reserves collapse, exploitation of oil resources in mature reservoirs is essential for meeting future energy demands. As conventional recovery methods currently used have become less efficient for the needs, there is a continuous demand of developing a new technology which helps in the upgradation of heavy crude oil. Microbial enhanced oil recovery (MEOR is an important tertiary oil recovery method which is cost-effective and eco-friendly technology to drive the residual oil trapped in the reservoirs. The potential of microorganisms to degrade heavy crude oil to reduce viscosity is considered to be very effective in MEOR. Earlier studies of MEOR (1950s were based on three broad areas: injection, dispersion, and propagation of microorganisms in petroleum reservoirs; selective degradation of oil components to improve flow characteristics; and production of metabolites by microorganisms and their effects. Since thermophilic spore-forming bacteria can thrive in very extreme conditions in oil reservoirs, they are the most suitable organisms for the purpose. This paper contains the review of work done with thermophilic spore-forming bacteria by different researchers.

Comparative genomic analysis of the thermophilic biomass-degrading fungi Myceliophthora thermophila and Thielavia terrestris

Energy Technology Data Exchange (ETDEWEB)

Berka, Randy M.; Grigoriev, Igor V.; Otillar, Robert; Salamov, Asaf; Grimwood, Jane; Reid, Ian; Ishmael, Nadeeza; John, Tricia; Darmond, Corinne; Moisan, Marie-Claude; Henrissat, Bernard; Coutinho, Pedro M.; Lombard, Vincent; Natvig, Donald O.; Lindquist, Erika; Schmutz, Jeremy; Lucas, Susan; Harris, Paul; Powlowski, Justin; Bellemare, Annie; Taylor, David; Butler, Gregory; de Vries, Ronald P.; Allijn, Iris E.; van den Brink, Joost; Ushinsky, Sophia; Storms, Reginald; Powell, Amy J.; Paulsen, Ian T.; Elbourne, Liam D. H.; Baker, Scott. E.; Magnuson, Jon; LaBoissiere, Sylvie; Clutterbuck, A. John; Martinez, Diego; Wogulis, Mark; Lopez de Leon, Alfredo; Rey, Michael W.; Tsang, Adrian

2011-05-16

Thermostable enzymes and thermophilic cell factories may afford economic advantages in the production of many chemicals and biomass-based fuels. Here we describe and compare the genomes of two thermophilic fungi, Myceliophthora thermophila and Thielavia terrestris. To our knowledge, these genomes are the first described for thermophilic eukaryotes and the first complete telomere-to-telomere genomes for filamentous fungi. Genome analyses and experimental data suggest that both thermophiles are capable of hydrolyzing all major polysaccharides found in biomass. Examination of transcriptome data and secreted proteins suggests that the two fungi use shared approaches in the hydrolysis of cellulose and xylan but distinct mechanisms in pectin degradation. Characterization of the biomass-hydrolyzing activity of recombinant enzymes suggests that these organisms are highly efficient in biomass decomposition at both moderate and high temperatures. Furthermore, we present evidence suggesting that aside from representing a potential reservoir of thermostable enzymes, thermophilic fungi are amenable to manipulation using classical and molecular genetics.

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...

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

International Nuclear Information System (INIS)

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

2002-01-01

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

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

Anaerobic thermophilic culture-system

Energy Technology Data Exchange (ETDEWEB)

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

1981-04-14

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

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 anaerobic digestion of Lurgi coal gasification wastewater in a UASB reactor

Energy Technology Data Exchange (ETDEWEB)

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

2011-02-15

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

Is arsenic biotransformation a detoxification mechanism for microorganisms?

International Nuclear Information System (INIS)

Rahman, M. Azizur; Hassler, Christel

2014-01-01

Arsenic (As) is extremely toxic to living organisms at high concentration. In aquatic systems, As exists in different chemical forms. The two major inorganic As (iAs) species are As V , which is thermodynamically stable in oxic waters, and As III , which is predominant in anoxic conditions. Photosynthetic microorganisms (e.g., phytoplankton and cyanobacteria) take up As V , biotransform it to As III , then biomethylate it to methylarsenic (MetAs) forms. Although As III is more toxic than As V , As III is much more easily excreted from the cells than As V . Therefore, majority of researchers consider the reduction of As V to As III as a detoxification process. The biomethylation process results in the conversion of toxic iAs to the less toxic pentavalent MetAs forms (monomethylarsonate; MMA V , dimethylarsonate; DMA V , and trimethylarsenic oxide; TMAO V ) and trimethylarsine (TMAO III ). However, biomethylation by microorganisms also produces monomethylarsenite (MMA III ) and dimethylarsenite (DMA III ), which are more toxic than iAs, as a result of biomethylation by the microorganisms, demonstrates the need to reconsider to what extent As biomethylation contributes to a detoxification process. In this review, we focused on the discussion of whether the biotransformation of As species in microorganisms is really a detoxification process with recent data

Identification of microorganisms associated with corrosion of offshore oil production systems

Science.gov (United States)

Sørensen, Ketil; Grigoryan, Aleksandr; Holmkvist, Lars; Skovhus, Torben; Thomsen, Uffe; Lundgaard, Thomas

2010-05-01

Microbiologically influenced corrosion (MIC) poses a major challenge to oil producers and distributors. The annual cost associated with MIC-related pipeline failures and general maintenance and surveillance of installations amounts to several billion dollar in the oil production sector alone. Hence, large efforts are undertaken by some producers to control and monitor microbial growth in pipelines and other installations, and extensive surveillance programs are carried out in order to detect and quantify potential MIC-promoting microorganisms. Traditionally, efforts to mitigate and survey microbial growth in oil production systems have focused on sulfate-reducing Bacteria (SRB), and microorganisms have usually been enumerated by the culture-dependent MPN (most probable number) -technique. Culture-independent molecular tools yielding much more detailed information about the microbial communities have now been implemented as a reliable tool for routine surveillance of oil production systems in the North Sea. This has resulted in new and hitherto unattainable information regarding the distribution of different microorganisms in hot reservoirs and associated oil production systems. This presentation will provide a review of recent insights regarding thermophilic microbial communities and their implication for steel corrosion in offshore oil production systems. Data collected from solids and biofilms in different corroded pipelines and tubes indicate that in addition to SRB, other groups such as methanogens and sulfate-reducing Archaea (SRA) are also involved in MIC. In the hot parts of the system where the temperature approaches 80 ⁰C, SRA closely related to Archaeoglobus fulgidus outnumber SRB by several orders of magnitude. Methanogens affiliated with the genus Methanothermococcus were shown to completely dominate the microbial community at the metal surface in a sample of highly corroded piping. Thus, the microbial communities associated with MIC appear to be more

Two-Step Oxidation of Refractory Gold Concentrates with Different Microbial Communities.

Science.gov (United States)

Wang, Guo-Hua; Xie, Jian-Ping; Li, Shou-Peng; Guo, Yu-Jie; Pan, Ying; Wu, Haiyan; Liu, Xin-Xing

2016-11-28

Bio-oxidation is an effective technology for treatment of refractory gold concentrates. However, the unsatisfactory oxidation rate and long residence time, which cause a lower cyanide leaching rate and gold recovery, are key factors that restrict the application of traditional bio-oxidation technology. In this study, the oxidation rate of refractory gold concentrates and the adaption of microorganisms were analyzed to evaluate a newly developed two-step pretreatment process, which includes a high temperature chemical oxidation step and a subsequent bio-oxidation step. The oxidation rate and recovery rate of gold were improved significantly after the two-step process. The results showed that the highest oxidation rate of sulfide sulfur could reach to 99.01 % with an extreme thermophile microbial community when the pulp density was 5%. Accordingly, the recovery rate of gold was elevated to 92.51%. Meanwhile, the results revealed that moderate thermophiles performed better than acidophilic mesophiles and extreme thermophiles, whose oxidation rates declined drastically when the pulp density was increased to 10% and 15%. The oxidation rates of sulfide sulfur with moderate thermophiles were 93.94% and 65.73% when the pulp density was increased to 10% and 15%, respectively. All these results indicated that the two-step pretreatment increased the oxidation rate of refractory gold concentrates and is a potential technology to pretreat the refractory sample. Meanwhile, owing to the sensitivity of the microbial community under different pulp density levels, the optimization of microbial community in bio-oxidation is necessary in industry.

Pb2+ Effects on Growth, Lipids, and Protein and DNA Profiles of the Thermophilic Bacterium Thermus Thermophilus

Directory of Open Access Journals (Sweden)

Barbara Nicolaus

2016-12-01

Full Text Available Extremophiles are organisms able to thrive in extreme environmental conditions and some of them show the ability to survive high doses of heavy metals thanks to defensive mechanisms provided by primary and secondary metabolic products, i.e., extremolytes, lipids, and extremozymes. This is why there is a growing scientific and industrial interest in the use of thermophilic bacteria in a host of tasks, from the environmental detoxification of heavy metal to industrial activities, such as bio-machining and bio-metallurgy. In this work Thermus thermophilus was challenged against increasing Pb2+ concentrations spanning from 0 to 300 ppm in order to ascertain the sensitiveness of this bacteria to the Pb environmental pollution and to give an insight on its heavy metal resistance mechanisms. Analysis of growth parameters, enzyme activities, protein profiles, and lipid membrane modifications were carried out. In addition, genotyping analysis of bacteria grown in the presence of Pb2+, using random amplified polymorphic DNA-PCR and DNA melting evaluation, were also performed. A better knowledge of the response of thermophilic bacteria to the different pollutants, as heavy metals, is necessary for optimizing their use in remediation or decontamination processes.

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)

Biobased production of alkanes and alkenes through metabolic engineering of microorganisms

DEFF Research Database (Denmark)

Kang, Min Kyoung; Nielsen, Jens

2017-01-01

Advancement in metabolic engineering of microorganisms has enabled bio-based production of a range of chemicals, and such engineered microorganism can be used for sustainable production leading to reduced carbon dioxide emission there. One area that has attained much interest is microbial...... hydrocarbon biosynthesis, and in particular, alkanes and alkenes are important high-value chemicals as they can be utilized for a broad range of industrial purposes as well as ‘drop-in’ biofuels. Some microorganisms have the ability to biosynthesize alkanes and alkenes naturally, but their production level...... is extremely low. Therefore, there have been various attempts to recruit other microbial cell factories for production of alkanes and alkenes by applying metabolic engineering strategies. Here we review different pathways and involved enzymes for alkane and alkene production and discuss bottlenecks...

Thermophilic composting of municipal solid waste

International Nuclear Information System (INIS)

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

2009-01-01

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

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.

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

Science.gov (United States)

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

2016-01-01

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

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.

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.

Supplement to thermophilic hydrolysis of liquid manures. Bilag til termofil hydrolyse af gylle

Energy Technology Data Exchange (ETDEWEB)

1990-07-01

A supplement to ''Thermophilic hydrolysis of liquid manures'' which contains descriptions of testing methods and results for determining the influence of additives such as propionic acid or triolein on chemical reactions in connection with the decomposition of liquid manures under thermophilic conditions. (AB).

Efficient utilization of xylanase and lipase producing thermophilic ...

African Journals Online (AJOL)

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

Production of thermophilic and acidophilic endoglucanases by ...

African Journals Online (AJOL)

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

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

Science.gov (United States)

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

2015-08-01

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

Discrimination of thermophilic and mesophilic proteins

Directory of Open Access Journals (Sweden)

Vaisman Iosif I

2010-05-01

Full Text Available Abstract Background There is a considerable literature on the source of the thermostability of proteins from thermophilic organisms. Understanding the mechanisms for this thermostability would provide insights into proteins generally and permit the design of synthetic hyperstable biocatalysts. Results We have systematically tested a large number of sequence and structure derived quantities for their ability to discriminate thermostable proteins from their non-thermostable orthologs using sets of mesophile-thermophile ortholog pairs. Most of the quantities tested correspond to properties previously reported to be associated with thermostability. Many of the structure related properties were derived from the Delaunay tessellation of protein structures. Conclusions Carefully selected sequence based indices discriminate better than purely structure based indices. Combined sequence and structure based indices improve performance somewhat further. Based on our analysis, the strongest contributors to thermostability are an increase in ion pairs on the protein surface and a more strongly hydrophobic interior.

Is arsenic biotransformation a detoxification mechanism for microorganisms?

Energy Technology Data Exchange (ETDEWEB)

Rahman, M. Azizur, E-mail: Mohammad.Rahman@uts.edu.au [Centre for Environmental Sustainability, School of the Environment, Faculty of Science, University of Technology, P.O. Box 123, Broadway, Sydney, NSW 2007 (Australia); Hassler, Christel [Marine and Lake Biogeochemistry, Institute F. A. Forel, University of Geneva, 10 rte de Suisse, Versoix, 1290 Switzerland (Switzerland)

2014-01-15

Arsenic (As) is extremely toxic to living organisms at high concentration. In aquatic systems, As exists in different chemical forms. The two major inorganic As (iAs) species are As{sup V}, which is thermodynamically stable in oxic waters, and As{sup III}, which is predominant in anoxic conditions. Photosynthetic microorganisms (e.g., phytoplankton and cyanobacteria) take up As{sup V}, biotransform it to As{sup III}, then biomethylate it to methylarsenic (MetAs) forms. Although As{sup III} is more toxic than As{sup V}, As{sup III} is much more easily excreted from the cells than As{sup V}. Therefore, majority of researchers consider the reduction of As{sup V} to As{sup III} as a detoxification process. The biomethylation process results in the conversion of toxic iAs to the less toxic pentavalent MetAs forms (monomethylarsonate; MMA{sup V}, dimethylarsonate; DMA{sup V}, and trimethylarsenic oxide; TMAO{sup V}) and trimethylarsine (TMAO{sup III}). However, biomethylation by microorganisms also produces monomethylarsenite (MMA{sup III}) and dimethylarsenite (DMA{sup III}), which are more toxic than iAs, as a result of biomethylation by the microorganisms, demonstrates the need to reconsider to what extent As biomethylation contributes to a detoxification process. In this review, we focused on the discussion of whether the biotransformation of As species in microorganisms is really a detoxification process with recent data.

Potential and utilization of thermophiles and thermostable enzymes in biorefining

Directory of Open Access Journals (Sweden)

Karlsson Eva

2007-03-01

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

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

Science.gov (United States)

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

2006-03-01

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

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

Directory of Open Access Journals (Sweden)

Fatemeh Azadian

2017-06-01

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

Exceptional thermal stability and organic solvent tolerance of an esterase expressed from a thermophilic host

DEFF Research Database (Denmark)

Mei, Yuxia; Peng, Nan; Zhao, Shumiao

2012-01-01

, giving SisEstA. Upon Escherichia coli expression, only the thioredoxin-tagged EstA recombinant protein was soluble. The fusion protein was then purified, and removing the protein tag yielded EcSisEstA. Both forms of the thermophilic EstA enzyme were characterized. We found that SisEstA formed dimer...... that of EcSisEstA at 90°C. This indicated that thermophilic enzymes yielded from homologous expression should be better biocatalysts than those obtained from mesophilic expression.......A protein expression system recently developed for the thermophilic crenarchaeon Sulfolobus islandicus was employed to produce recombinant protein for EstA, a thermophilic esterase encoded in the same organism. Large amounts of protein were readily obtained by an affinity protein purification...

Concomitant production of cellulase and xylanase by thermophilic mould Sporotrichum thermophile in solid state fermentation and their applicability in bread making.

Science.gov (United States)

Bala, Anju; Singh, Bijender

2017-06-01

Sporotrichum thermophile BJAMDU5 secreted high titres of xylanolytic and cellulolytic enzymes in solid state fermentation using mixture of wheat straw and cotton oil cake (ratio 1:1) at 45 °C, pH 5.0 after 72 h inoculated with 2.9 × 10 7  CFU/mL conidiospores. Supplementation of solid medium with lactose and ammonium sulphate further enhanced the production of hydrolytic enzymes. Among different surfactants studied, Tween 80 enhanced the production of all enzymes [3455 U/g DMR (dry mouldy residue), 879.26 U/g DMR, 976.28 U/g DMR and 35.10 U/g DMR for xylanase, CMCase (Carboxymethylcellulase), FPase (Filter paper activity) and β-glucosidase, respectively] as compared to other surfactants. Recycling of solid substrate reduced the production of all these enzymes after second cycle. End products analysis by TLC showed the ability of hydrolytic enzymes of S. thermophile to liberate monomeric (xylose and glucose) as well as oligomeric (xylobiose, cellobiose and higher ones) sugars. Supplementation of enzyme resulted in improved nutritional properties of the bread. Formation of oligomeric sugars by xylanase enzyme of S. thermophile BJAMDU5 make it a good candidate in food industry.

Microorganisms applying for artificial soil regeneration technology in space greenhouses

Science.gov (United States)

Krivobok, A. S.

2012-04-01

The space greenhouse and technology for growing plants are being designed in frame of bio-technical life support systems development. During long-term space missions such greenhouse could provide the crew with vitamins and rough plant fiber. One of the important elements of the plant cultivation technology in the absence of earth gravity is organization and support the optimum root area. The capillary-porous substrate composed of anionites (FIBAN -1) and cationites (FIBAN -22-1) synthetic salt-saturated fibers is developed for plant cultivation in space and named "BIONA-V3". The BIONA main features are high productivity and usability. But the pointed features are not constant: the substrate productivity will be decreasing gradually from vegetation to vegetation course of plant residues and root secretions accumulation. Also, the basic hydro-physical characteristic of root zone will be shifted. Furthermore, saprotrophic microflora will develop and lead to increasing the level of microbial contamination of whole inhabit isolated module. Due to these changes the substrate useful life is limited and store mass is increased in long-term missions. For overhaul-period renewal it' necessary to remove the roots residues and other organic accumulation providing safety of the substrate capillary-porous structure. The basic components of 24-days old plant roots (Brassica chinensis, L) are cellulose (35 %) hemicellulose (11 %) and lignin (10 %). We see that one of the possible ways for roots residues removal from fibrous BIONA is microorganisms applying with strong cellulolytic and ligninolytic activities. The fungi Trichoderma sp., cellulolytic bacteria associations, and some genus of anaerobic thermophilic cellulolitic bacteria have been used for roots residues biodegradation. In case of applying cellulolytic fungi Trichoderma sp. considerable decrease of microcrystalline cellulose has been noted in both liquid and solid state fermentation. Cellulolytic fungi weight has been

Molecular characterization of thermophilic Campylobacter species ...

African Journals Online (AJOL)

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

The extreme environments and their microbes as models for extraterrestrial life

Science.gov (United States)

Seckbach, J.; Oren, A.; Chela-Flores, J.

2008-09-01

Life exists almost everywhere on Earth. Presence of liquid water is a prerequisite for life (Oren, 2008). Living organisms are not only found in `normal' habitats (from the anthropocentric view). Many types, especially of microorganisms, not only tolerate harsh environmental conditions, but even thive in them. Such organisms that resist very harsh physical and chemical conditions in their habitats are termed `extremophiles'. Some extremophilic microorganisms are able to overcome more than one type of extreme conditions in their environment. For example, some `polyextremophiles' grow under hundreds of atmospheres of hydrostatic pressure (barophiles) and at very low, or alternatively at very high temperatures. In many hot springs there are acido-thermophiles that tolerate elevated temperatures and very low pH levels (e.g. the Cyanidium caldarium group, see Seckbach 1994). Members of Cyanidium are able to thrive in pure CO2, a condition not tolerated by most algae (Seckbach et al., 1970). Some thermophilic Archaea grow at temperatures up to 1130C and possibly even higher. In the Arctic and Antarctic regions and in the permafrost region in Siberia there are cold-loving microorganisms (psychrophiles) which are able to grow at -200C. Many types of Bacteria and Archaea tolerate extreme dryness, and spores of Bacillus and relatives that have been encapsulated within salt crystals may have survived in a dormant state for thousands and even millions of years, and still can be revived today. Other extremophiles tolerate salt concentrations up to saturation. Halophilic microorganisms such as found in the Dead Sea or in the Great Salt Lake have developed different strategies to cope with the high osmotic pressure of their environment. Some (e.g. the unicellular green alga Dunaliella salina) balance the salts in their medium by accumulating organic compounds such as glycerol. Others (halophilic Archaea of the order Halobacteriales, as well as a few representatives of the

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.

Novel thermophilic hemicellulases for the conversion of lignocellulose for second generation biorefineries.

Science.gov (United States)

Cobucci-Ponzano, Beatrice; Strazzulli, Andrea; Iacono, Roberta; Masturzo, Giuseppe; Giglio, Rosa; Rossi, Mosè; Moracci, Marco

2015-10-01

The biotransformation of lignocellulose biomasses into fermentable sugars is a very complex procedure including, as one of the most critical steps, the (hemi) cellulose hydrolysis by specific enzymatic cocktails. We explored here, the potential of stable glycoside hydrolases from thermophilic organisms, so far not used in commercial enzymatic preparations, for the conversion of glucuronoxylan, the major hemicellulose of several energy crops. Searches in the genomes of thermophilic bacteria led to the identification, efficient production, and detailed characterization of novel xylanase and α-glucuronidase from Alicyclobacillus acidocaldarius (GH10-XA and GH67-GA, respectively) and a α-glucuronidase from Caldicellulosiruptor saccharolyticus (GH67-GC). Remarkably, GH10-XA, if compared to other thermophilic xylanases from this family, coupled good specificity on beechwood xylan and the best stability at 65 °C (3.5 days). In addition, GH67-GC was the most stable α-glucuronidases from this family and the first able to hydrolyse both aldouronic acid and aryl-α-glucuronic acid substrates. These enzymes, led to the very efficient hydrolysis of beechwood xylan by using 7- to 9-fold less protein (concentrations thermophilic enzymes. In addition, remarkably, together with a thermophilic β-xylosidase, they catalyzed the production of xylose from the smart cooking pre-treated biomass of one of the most promising energy crops for second generation biorefineries. We demonstrated that search by the CAZy Data Bank of currently available genomes and detailed enzymatic characterization of recombinant enzymes allow the identification of glycoside hydrolases with novel and interesting properties and applications. Copyright © 2015 Elsevier Inc. All rights reserved.

New insights into microbial adaptation to extreme saline environments

Directory of Open Access Journals (Sweden)

Vauclare P.

2014-02-01

Full Text Available Extreme halophiles are microorganisms adapted to low water activity living at the upper salt concentration that life can tolerate. We review here recent data that specify the main factors, which determine their peculiar salt-dependent biochemistry. The data suggested that evolution proceeds by stage to modify the molecular dynamics properties of the entire proteome. Extreme halophiles therefore represent tractable models to understand how fast and to what extent microorganisms adapt to environmental changes. Halophiles are also robust organisms, capable to resist multiple stressors. Preliminary studies indicated that they have developed a cellular response specifically aimed to survive when the salt condition fluctuates. Because of these properties halophilic organisms deserve special attention in the search for traces of life on other planets.

Thermophilic bacteria in Moroccan hot springs, salt marshes and desert soils

OpenAIRE

Aanniz,Tarik; Ouadghiri,Mouna; Melloul,Marouane; Swings,Jean; Elfahime,Elmostafa; Ibijbijen,Jamal; Ismaili,Mohamed; Amar,Mohamed

2015-01-01

The diversity of thermophilic bacteria was investigated in four hot springs, three salt marshes and 12 desert sites in Morocco. Two hundred and forty (240) thermophilic bacteria were recovered, identified and characterized. All isolates were Gram positive, rod-shaped, spore forming and halotolerant. Based on BOXA1R-PCR and 16S rRNA gene sequencing, the recovered isolates were dominated by the genus Bacillus (97.5%) represented by B. licheniformis (119), B. aerius (44), B. sonorensis (33), B. ...

Aspergillus fumigatus and other thermophilic fungi in nests of wetland birds.

Science.gov (United States)

Korniłłowicz-Kowalska, Teresa; Kitowski, Ignacy

2013-02-01

A study was performed on the numbers and species diversity of thermophilic fungi (growing at 45 °C in vitro) in 38 nests of 9 species of wetland birds, taking into account the physicochemical properties of the nests and the bird species. It was found that in nests with the maximum weight (nests of Mute Swan), the number and diversity of thermophilic fungi were significantly greater than in other nests, with lower weight. The diversity of the thermophilic biota was positively correlated with the individual mass of bird and with the level of phosphorus in the nests. The dominant species within the mycobiota under study was Aspergillus fumigatus which inhabited 95% of the nests under study, with average frequency of ca. 650 cfu g(-1) of dry mass of the nest material. In a majority of the nests studied (nests of 7 bird species), the share of A. fumigatus exceeded 50% of the total fungi growing at 45 °C. Significantly higher frequencies of the fungal species were characteristic of the nests of small and medium-sized piscivorous species, compared with the other bird species. The number of A. fumigatus increased with increase in the moisture level of the nests, whereas the frequency of occurrence of that opportunistic pathogen, opposite to the general frequency of thermophilic mycobiota, was negatively correlated with the level of phosphorus in the nest material, and with the body mass and length of the birds. The authors indicate the causes of varied growth of thermophilic fungi in nests of wetland birds and, in particular, present a discussion of the causes of accumulation of A. fumigatus, the related threats to the birds, and its role as a source of transmission in the epidemiological chain of aspergillosis.

In vivo and in vitro protein imaging in thermophilic archaea by exploiting a novel protein tag.

Science.gov (United States)

Visone, Valeria; Han, Wenyuan; Perugino, Giuseppe; Del Monaco, Giovanni; She, Qunxin; Rossi, Mosè; Valenti, Anna; Ciaramella, Maria

2017-01-01

Protein imaging, allowing a wide variety of biological studies both in vitro and in vivo, is of great importance in modern biology. Protein and peptide tags fused to proteins of interest provide the opportunity to elucidate protein location and functions, detect protein-protein interactions, and measure protein activity and kinetics in living cells. Whereas several tags are suitable for protein imaging in mesophilic organisms, the application of this approach to microorganisms living at high temperature has lagged behind. Archaea provide an excellent and unique model for understanding basic cell biology mechanisms. Here, we present the development of a toolkit for protein imaging in the hyperthermophilic archaeon Sulfolobus islandicus. The system relies on a thermostable protein tag (H5) constructed by engineering the alkylguanine-DNA-alkyl-transferase protein of Sulfolobus solfataricus, which can be covalently labeled using a wide range of small molecules. As a suitable host, we constructed, by CRISPR-based genome-editing technology, a S. islandicus mutant strain deleted for the alkylguanine-DNA-alkyl-transferase gene (Δogt). Introduction of a plasmid-borne H5 gene in this strain led to production of a functional H5 protein, which was successfully labeled with appropriate fluorescent molecules and visualized in cell extracts as well as in Δogt live cells. H5 was fused to reverse gyrase, a peculiar thermophile-specific DNA topoisomerase endowed with positive supercoiling activity, and allowed visualization of the enzyme in living cells. To the best of our knowledge, this is the first report of in vivo imaging of any protein of a thermophilic archaeon, filling an important gap in available tools for cell biology studies in these organisms.

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

Directory of Open Access Journals (Sweden)

Judit Ribera

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

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

Science.gov (United States)

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

2017-01-01

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

Expression of Critical Sulfur- and Iron-Oxidation Genes and the Community Dynamics During Bioleaching of Chalcopyrite Concentrate by Moderate Thermophiles.

Science.gov (United States)

Zhou, Dan; Peng, Tangjian; Zhou, Hongbo; Liu, Xueduan; Gu, Guohua; Chen, Miao; Qiu, Guanzhou; Zeng, Weimin

2015-07-01

Sulfate adenylyltransferase gene and 4Fe-4S ferredoxin gene are the key genes related to sulfur and iron oxidations during bioleaching system, respectively. In order to better understand the bioleaching and microorganism synergistic mechanism in chalcopyrite bioleaching by mixed culture of moderate thermophiles, expressions of the two energy metabolism genes and community dynamics of free and attached microorganisms were investigated. Specific primers were designed for real-time quantitative PCR to study the expression of these genes. Real-time PCR results showed that sulfate adenylyltransferase gene was more highly expressed in Sulfobacillus thermosulfidooxidans than that in Acidithiobacillus caldus, and expression of 4Fe-4S ferredoxin gene was higher in Ferroplasma thermophilum than that in S. thermosulfidooxidans and Leptospirillum ferriphilum. The results indicated that in the bioleaching system of chalcopyrite concentrate, sulfur and iron oxidations were mainly performed by S. thermosulfidooxidans and F. thermophilum, respectively. The community dynamics results revealed that S. thermosulfidooxidans took up the largest proportion during the whole period, followed by F. thermophilum, A. caldus, and L. ferriphilum. The CCA analysis showed that 4Fe-4S ferredoxin gene expression was mainly affected (positively correlated) by high pH and elevated concentration of ferrous ion, while no factor was observed to prominently influence the expression of sulfate adenylyltransferase gene.

Molecular diversity of thermophilic bacteria isolated from Pasinler hot spring (Erzurum, Turkey)

OpenAIRE

ADIGÜZEL, Ahmet; İNAN, Kadriye; ŞAHİN, Fikrettin; ARASOĞLU, Tulin; GÜLLÜCE, Medine

2011-01-01

The present study was conducted to determine the phenotypic and genotypic characterization of thermophilic bacteria isolated from Pasinler hot spring, Erzurum, Turkey. Fatty acid profiles, BOX PCR fingerprints, and 16S rDNA sequence data were used for the phenotypic and genotypic characterization of thermophilic bacteria. Totally 9 different bacterial strains were selected based on morphological, physiological, and biochemical tests. These strains were characterized by molecular tests includi...

Screening of complex thermophilic microbial community and ...

African Journals Online (AJOL)

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

Alkane inducible proteins in Geobacillus thermoleovorans B23

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Kato Tomohisa

2009-03-01

Full Text Available Abstract Background Initial step of β-oxidation is catalyzed by acyl-CoA dehydrogenase in prokaryotes and mitochondria, while acyl-CoA oxidase primarily functions in the peroxisomes of eukaryotes. Oxidase reaction accompanies emission of toxic by-product reactive oxygen molecules including superoxide anion, and superoxide dismutase and catalase activities are essential to detoxify them in the peroxisomes. Although there is an argument about whether primitive life was born and evolved under high temperature conditions, thermophilic archaea apparently share living systems with both bacteria and eukaryotes. We hypothesized that alkane degradation pathways in thermophilic microorganisms could be premature and useful to understand their evolution. Results An extremely thermophilic and alkane degrading Geobacillus thermoleovorans B23 was previously isolated from a deep subsurface oil reservoir in Japan. In the present study, we identified novel membrane proteins (P16, P21 and superoxide dismutase (P24 whose production levels were significantly increased upon alkane degradation. Unlike other bacteria acyl-CoA oxidase and catalase activities were also increased in strain B23 by addition of alkane. Conclusion We first suggested that peroxisomal β-oxidation system exists in bacteria. This eukaryotic-type alkane degradation pathway in thermophilic bacterial cells might be a vestige of primitive living cell systems that had evolved into eukaryotes.

Thermophilic bacteria in Moroccan hot springs, salt marshes and desert soils.

Science.gov (United States)

Aanniz, Tarik; Ouadghiri, Mouna; Melloul, Marouane; Swings, Jean; Elfahime, Elmostafa; Ibijbijen, Jamal; Ismaili, Mohamed; Amar, Mohamed

2015-06-01

The diversity of thermophilic bacteria was investigated in four hot springs, three salt marshes and 12 desert sites in Morocco. Two hundred and forty (240) thermophilic bacteria were recovered, identified and characterized. All isolates were Gram positive, rod-shaped, spore forming and halotolerant. Based on BOXA1R-PCR and 16S rRNA gene sequencing, the recovered isolates were dominated by the genus Bacillus (97.5%) represented by B. licheniformis (119), B. aerius (44), B. sonorensis (33), B. subtilis (subsp. spizizenii (2) and subsp. inaquosurum (6)), B. amyloliquefaciens (subsp. amyloliquefaciens (4) and subsp. plantarum (4)), B. tequilensis (3), B. pumilus (3) and Bacillus sp. (19). Only six isolates (2.5%) belonged to the genus Aeribacillus represented by A. pallidus (4) and Aeribacillus sp. (2). In this study, B. aerius and B. tequilensis are described for the first time as thermophilic bacteria. Moreover, 71.25%, 50.41% and 5.41% of total strains exhibited high amylolytic, proteolytic or cellulolytic activity respectively.

Thermophilic bacteria in Moroccan hot springs, salt marshes and desert soils

Directory of Open Access Journals (Sweden)

Tarik Aanniz

2015-06-01

Full Text Available The diversity of thermophilic bacteria was investigated in four hot springs, three salt marshes and 12 desert sites in Morocco. Two hundred and forty (240 thermophilic bacteria were recovered, identified and characterized. All isolates were Gram positive, rod-shaped, spore forming and halotolerant. Based on BOXA1R-PCR and 16S rRNA gene sequencing, the recovered isolates were dominated by the genus Bacillus (97.5% represented by B. licheniformis (119, B. aerius (44, B. sonorensis (33, B. subtilis (subsp. spizizenii (2 and subsp. inaquosurum (6, B. amyloliquefaciens (subsp. amyloliquefaciens (4 and subsp. plantarum (4, B. tequilensis (3, B. pumilus (3 and Bacillus sp. (19. Only six isolates (2.5% belonged to the genus Aeribacillus represented by A. pallidus (4 and Aeribacillus sp. (2. In this study, B. aerius and B. tequilensis are described for the first time as thermophilic bacteria. Moreover, 71.25%, 50.41% and 5.41% of total strains exhibited high amylolytic, proteolytic or cellulolytic activity respectively.

Widespread Disulfide Bonding in Proteins from Thermophilic Archaea

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Julien Jorda

2011-01-01

Full Text Available Disulfide bonds are generally not used to stabilize proteins in the cytosolic compartments of bacteria or eukaryotic cells, owing to the chemically reducing nature of those environments. In contrast, certain thermophilic archaea use disulfide bonding as a major mechanism for protein stabilization. Here, we provide a current survey of completely sequenced genomes, applying computational methods to estimate the use of disulfide bonding across the Archaea. Microbes belonging to the Crenarchaeal branch, which are essentially all hyperthermophilic, are universally rich in disulfide bonding while lesser degrees of disulfide bonding are found among the thermophilic Euryarchaea, excluding those that are methanogenic. The results help clarify which parts of the archaeal lineage are likely to yield more examples and additional specific data on protein disulfide bonding, as increasing genomic sequencing efforts are brought to bear.

Widespread disulfide bonding in proteins from thermophilic archaea.

Science.gov (United States)

Jorda, Julien; Yeates, Todd O

2011-01-01

Disulfide bonds are generally not used to stabilize proteins in the cytosolic compartments of bacteria or eukaryotic cells, owing to the chemically reducing nature of those environments. In contrast, certain thermophilic archaea use disulfide bonding as a major mechanism for protein stabilization. Here, we provide a current survey of completely sequenced genomes, applying computational methods to estimate the use of disulfide bonding across the Archaea. Microbes belonging to the Crenarchaeal branch, which are essentially all hyperthermophilic, are universally rich in disulfide bonding while lesser degrees of disulfide bonding are found among the thermophilic Euryarchaea, excluding those that are methanogenic. The results help clarify which parts of the archaeal lineage are likely to yield more examples and additional specific data on protein disulfide bonding, as increasing genomic sequencing efforts are brought to bear.

Evolvability of thermophilic proteins from archaea and bacteria.

Science.gov (United States)

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

2013-07-16

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

Production of bioplastics and hydrogen gas by photosynthetic microorganisms

Science.gov (United States)

Yasuo, Asada; Masato, Miyake; Jun, Miyake

1998-03-01

Our efforts have been aimed at the technological basis of photosynthetic-microbial production of materials and an energy carrier. We report here accumulation of poly-(3-hydroxybutyrate) (PHB), a raw material of biodegradable plastics and for production of hydrogen gas, and a renewable energy carrier by photosynthetic microorganisms (tentatively defined as cyanobacteria plus photosynthetic bateria, in this report). A thermophilic cyanobacterium, Synechococcus sp. MA19 that accumulates PHB at more than 20% of cell dry wt under nitrogen-starved conditions was isolated and microbiologically identified. The mechanism of PHB accumulation was studied. A mesophilic Synechococcus PCC7942 was transformed with the genes encoding PHB-synthesizing enzymes from Alcaligenes eutrophus. The transformant accumulated PHB under nitrogen-starved conditions. The optimal conditions for PHB accumulation by a photosynthetic bacterium grown on acetate were studied. Hydrogen production by photosynthetic microorganisms was studied. Cyanobacteria can produce hydrogen gas by nitrogenase or hydrogenase. Hydrogen production mediated by native hydrogenase in cyanobacteria was revealed to be in the dark anaerobic degradation of intracellular glycogen. A new system for light-dependent hydrogen production was targeted. In vitro and in vivo coupling of cyanobacterial ferredoxin with a heterologous hydrogenase was shown to produce hydrogen under light conditions. A trial for genetic trasformation of Synechococcus PCC7942 with the hydrogenase gene from Clostridium pasteurianum is going on. The strong hydrogen producers among photosynthetic bacteria were isolated and characterized. Co-culture of Rhodobacter and Clostriumdium was applied to produce hydrogen from glucose. Conversely in the case of cyanobacteria, genetic regulation of photosynthetic proteins was intended to improve conversion efficiency in hydrogen production by the photosynthetic bacterium, Rhodobacter sphaeroides RV. A mutant acquired by

Candidatus Nitrosocaldus cavascurensis, an Ammonia Oxidizing, Extremely Thermophilic Archaeon with a Highly Mobile Genome.

Science.gov (United States)

Abby, Sophie S; Melcher, Michael; Kerou, Melina; Krupovic, Mart; Stieglmeier, Michaela; Rossel, Claudia; Pfeifer, Kevin; Schleper, Christa

2018-01-01

Ammonia oxidizing archaea (AOA) of the phylum Thaumarchaeota are widespread in moderate environments but their occurrence and activity has also been demonstrated in hot springs. Here we present the first enrichment of a thermophilic representative with a sequenced genome, which facilitates the search for adaptive strategies and for traits that shape the evolution of Thaumarchaeota. Candidatus Nitrosocaldus cavascurensis has been enriched from a hot spring in Ischia, Italy. It grows optimally at 68°C under chemolithoautotrophic conditions on ammonia or urea converting ammonia stoichiometrically into nitrite with a generation time of approximately 23 h. Phylogenetic analyses based on ribosomal proteins place the organism as a sister group to all known mesophilic AOA. The 1.58 Mb genome of Ca. N. cavascurensis harbors an amo AXCB gene cluster encoding ammonia monooxygenase and genes for a 3-hydroxypropionate/4-hydroxybutyrate pathway for autotrophic carbon fixation, but also genes that indicate potential alternative energy metabolisms. Although a bona fide gene for nitrite reductase is missing, the organism is sensitive to NO-scavenging, underlining the potential importance of this compound for AOA metabolism. Ca. N. cavascurensis is distinct from all other AOA in its gene repertoire for replication, cell division and repair. Its genome has an impressive array of mobile genetic elements and other recently acquired gene sets, including conjugative systems, a provirus, transposons and cell appendages. Some of these elements indicate recent exchange with the environment, whereas others seem to have been domesticated and might convey crucial metabolic traits.

Discovery of Microorganisms and Enzymes Involved in High-Solids Decomposition of Rice Straw Using Metagenomic Analyses

Science.gov (United States)

D’haeseleer, Patrik; Khudyakov, Jane; Burd, Helcio; Hadi, Masood; Simmons, Blake A.; Singer, Steven W.; Thelen, Michael P.; VanderGheynst, Jean S.

2013-01-01

High-solids incubations were performed to enrich for microbial communities and enzymes that decompose rice straw under mesophilic (35°C) and thermophilic (55°C) conditions. Thermophilic enrichments yielded a community that was 7.5 times more metabolically active on rice straw than mesophilic enrichments. Extracted xylanase and endoglucanse activities were also 2.6 and 13.4 times greater, respectively, for thermophilic enrichments. Metagenome sequencing was performed on enriched communities to determine community composition and mine for genes encoding lignocellulolytic enzymes. Proteobacteria were found to dominate the mesophilic community while Actinobacteria were most abundant in the thermophilic community. Analysis of protein family representation in each metagenome indicated that cellobiohydrolases containing carbohydrate binding module 2 (CBM2) were significantly overrepresented in the thermophilic community. Micromonospora, a member of Actinobacteria, primarily housed these genes in the thermophilic community. In light of these findings, Micromonospora and other closely related Actinobacteria genera appear to be promising sources of thermophilic lignocellulolytic enzymes for rice straw deconstruction under high-solids conditions. Furthermore, these discoveries warrant future research to determine if exoglucanases with CBM2 represent thermostable enzymes tolerant to the process conditions expected to be encountered during industrial biofuel production. PMID:24205054

Discovery of microorganisms and enzymes involved in high-solids decomposition of rice straw using metagenomic analyses.

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Amitha P Reddy

Full Text Available High-solids incubations were performed to enrich for microbial communities and enzymes that decompose rice straw under mesophilic (35°C and thermophilic (55°C conditions. Thermophilic enrichments yielded a community that was 7.5 times more metabolically active on rice straw than mesophilic enrichments. Extracted xylanase and endoglucanse activities were also 2.6 and 13.4 times greater, respectively, for thermophilic enrichments. Metagenome sequencing was performed on enriched communities to determine community composition and mine for genes encoding lignocellulolytic enzymes. Proteobacteria were found to dominate the mesophilic community while Actinobacteria were most abundant in the thermophilic community. Analysis of protein family representation in each metagenome indicated that cellobiohydrolases containing carbohydrate binding module 2 (CBM2 were significantly overrepresented in the thermophilic community. Micromonospora, a member of Actinobacteria, primarily housed these genes in the thermophilic community. In light of these findings, Micromonospora and other closely related Actinobacteria genera appear to be promising sources of thermophilic lignocellulolytic enzymes for rice straw deconstruction under high-solids conditions. Furthermore, these discoveries warrant future research to determine if exoglucanases with CBM2 represent thermostable enzymes tolerant to the process conditions expected to be encountered during industrial biofuel production.

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

Science.gov (United States)

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

2016-06-16

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

Roles of thermophilic thiosulfate-reducing bacteria and methanogenic archaea in the biocorrosion of oil pipelines

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Renxing eLiang

2014-03-01

Full Text Available Thermophilic sulfide-producing microorganisms from an oil pipeline network were enumerated with different sulfur oxyanions as electron acceptors at 55 oC. Most-probable number (MPN analysis showed that thiosulfate-reducing bacteria were the most numerous sulfidogenic microorganisms in pipeline inspection gauge (PIG scrapings. Thiosulfate-reducing and methanogenic enrichments were obtained from the MPN cultures that were able to use yeast extract as the electron donor. Molecular analysis revealed that both enrichments harbored the same dominant bacterium, which belonged to the genus Anaerobaculum. The dominant archaeon in the methanogenic enrichment was affiliated with the genus Methanothermobacter. With yeast extract as the electron donor, the general corrosion rate by the thiosulfate-reducing enrichment (8.43 ± 1.40 milli-inch per year, abbreviated as mpy was about 5.5 times greater than the abiotic control (1.49 ± 0.15 mpy, while the comparable measures for the methanogenic culture were 2.03 ± 0.49 mpy and 0.62 ± 0.07 mpy, respectively. Total iron analysis in the cultures largely accounted for the mass loss of iron measured in the weight loss determinations. Profilometry analysis of polished steel coupons incubated in the presence of the thiosulfate-reducing enrichment revealed 59 pits over an area of 71.16 mm2, while only 6 pits were evident in the corresponding methanogenic incubations. The results show the importance of thiosulfate-utilizing, sulfide-producing fermentative bacteria such as Anaerobaculum sp. in the corrosion of carbon steel, but also suggest that Anaerobaculum sp. are of far less concern when growing syntrophically with methanogens.

Roles of thermophilic thiosulfate-reducing bacteria and methanogenic archaea in the biocorrosion of oil pipelines.

Science.gov (United States)

Liang, Renxing; Grizzle, Robert S; Duncan, Kathleen E; McInerney, Michael J; Suflita, Joseph M

2014-01-01

Thermophilic sulfide-producing microorganisms from an oil pipeline network were enumerated with different sulfur oxyanions as electron acceptors at 55°C. Most-probable number (MPN) analysis showed that thiosulfate-reducing bacteria were the most numerous sulfidogenic microorganisms in pipeline inspection gauge (PIG) scrapings. Thiosulfate-reducing and methanogenic enrichments were obtained from the MPN cultures that were able to use yeast extract as the electron donor. Molecular analysis revealed that both enrichments harbored the same dominant bacterium, which belonged to the genus Anaerobaculum. The dominant archaeon in the methanogenic enrichment was affiliated with the genus Methanothermobacter. With yeast extract as the electron donor, the general corrosion rate by the thiosulfate-reducing enrichment (8.43 ± 1.40 milli-inch per year, abbreviated as mpy) was about 5.5 times greater than the abiotic control (1.49 ± 0.15 mpy), while the comparable measures for the methanogenic culture were 2.03 ± 0.49 mpy and 0.62 ± 0.07 mpy, respectively. Total iron analysis in the cultures largely accounted for the mass loss of iron measured in the weight loss determinations. Profilometry analysis of polished steel coupons incubated in the presence of the thiosulfate-reducing enrichment revealed 59 pits over an area of 71.16 mm(2), while only 6 pits were evident in the corresponding methanogenic incubations. The results show the importance of thiosulfate-utilizing, sulfide-producing fermentative bacteria such as Anaerobaculum sp. in the corrosion of carbon steel, but also suggest that Anaerobaculum sp. are of far less concern when growing syntrophically with methanogens.

Succession and diversity of microorganisms and their association with physicochemical properties during green waste thermophilic composting.

Science.gov (United States)

Liu, Ling; Wang, Shuqi; Guo, Xiaoping; Zhao, Tingning; Zhang, Bolin

2018-03-01

A comprehensive characterization of the bacterial diversity associated to thermophilic stages of green waste composting was achieved. In this study, eight different treatments (T1-T8) and three replicated lab-scale green waste composting were carried out to compare the effect of the cellulase (i.e. 0, 2%), microbial inoculum (i.e. 0, 2 and 4%) and particle size (i.e. 2 and 5 mm) on bacterial community structure. Physicochemical properties and bacterial communities of T1-T8 composts were observed, and the bacterial structure and diversity were examined by high-throughput sequencing via a MiSeq platform. The results showed that the most abundant phyla among the treatments were the Firmicutes, Chloroflexi and Proteobacteria. The shannon index and non-metric multidimensional scaling (NMDS) showed higher bacterial abundance and diversity at the metaphase of composting. Comparing with 5-mm treatments, particle size of 2-mm had a richer diversity of bacterial communities. The addition of cellulase and a microbial inoculum could promote the fermentation temperature, reduce the compost pH and C/N ratio and result in higher GI index. The humic substance (HS) and humic acid (HA) contents for 2-mm particle size treatments were higher than those of 5-mm treatments. Canonical correspondence analysis suggested that differences in bacterial abundance and diversity significantly correlated with HA, E 4 /E 6 and temperature, and the relationship between bacterial diversity and environmental parameters was affected by composting stages. Based on these results, the application of cellulase to promote green waste composting was feasible, and particle size was identified as a potential control of composting physicochemical properties and bacterial diversity. Copyright © 2017 Elsevier Ltd. All rights reserved.

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...

Magnetotactic Bacteria from Extreme Environments

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Christopher T. Lefèvre

2013-03-01

Full Text Available Magnetotactic bacteria (MTB represent a diverse collection of motile prokaryotes that biomineralize intracellular, membrane-bounded, tens-of-nanometer-sized crystals of a magnetic mineral called magnetosomes. Magnetosome minerals consist of either magnetite (Fe3O4 or greigite (Fe3S4 and cause cells to align along the Earth’s geomagnetic field lines as they swim, a trait called magnetotaxis. MTB are known to mainly inhabit the oxic–anoxic interface (OAI in water columns or sediments of aquatic habitats and it is currently thought that magnetosomes function as a means of making chemotaxis more efficient in locating and maintaining an optimal position for growth and survival at the OAI. Known cultured and uncultured MTB are phylogenetically associated with the Alpha-, Gamma- and Deltaproteobacteria classes of the phylum Proteobacteria, the Nitrospirae phylum and the candidate division OP3, part of the Planctomycetes-Verrucomicrobia-Chlamydiae (PVC bacterial superphylum. MTB are generally thought to be ubiquitous in aquatic environments as they are cosmopolitan in distribution and have been found in every continent although for years MTB were thought to be restricted to habitats with pH values near neutral and at ambient temperature. Recently, however, moderate thermophilic and alkaliphilic MTB have been described including: an uncultured, moderately thermophilic magnetotactic bacterium present in hot springs in northern Nevada with a probable upper growth limit of about 63 °C; and several strains of obligately alkaliphilic MTB isolated in pure culture from different aquatic habitats in California, including the hypersaline, extremely alkaline Mono Lake, with an optimal growth pH of >9.0.

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...

Micro-Organ Device

Science.gov (United States)

Gonda, Steve R. (Inventor); Chang, Robert C. (Inventor); Starly, Binil (Inventor); Culbertson, Christopher (Inventor); Holtorf, Heidi L. (Inventor); Sun, Wei (Inventor); Leslie, Julia (Inventor)

2013-01-01

A method for fabricating a micro-organ device comprises providing a microscale support having one or more microfluidic channels and one or more micro-chambers for housing a micro-organ and printing a micro-organ on the microscale support using a cell suspension in a syringe controlled by a computer-aided tissue engineering system, wherein the cell suspension comprises cells suspended in a solution containing a material that functions as a three-dimensional scaffold. The printing is performed with the computer-aided tissue engineering system according to a particular pattern. The micro-organ device comprises at least one micro-chamber each housing a micro-organ; and at least one microfluidic channel connected to the micro-chamber, wherein the micro-organ comprises cells arranged in a configuration that includes microscale spacing between portions of the cells to facilitate diffusion exchange between the cells and a medium supplied from the at least one microfluidic channel.

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

Science.gov (United States)

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

2009-04-01

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

The winds of (evolutionary) change: Breathing new life into microbiology

Energy Technology Data Exchange (ETDEWEB)

Olsen, G.J.; Woese, C.R. [Univ. of Illinois, Urbana, IL (United States). Dept. of Microbiology; Overbeek, R.A. [Argonne National Lab., IL (United States)

1996-03-01

To date, over 1500 prokaryotes have been characterized by small subunit rRNA sequencing and molecular phylogeny has had an equally profound effect on our understanding of relationship among eukaryotic microorganisms. The universal phylogenetic tree readily shows however how artificial the strong distinction between the eukaryote and prokaryotes has become. The split between the Archaea and the Bacteria is now recognized as the primary phylogenetic division and that the Eucarya have branched from the same side of the tree as the Archaea. Both prokaryotic domains would seem to be of thermophilic origin suggesting that life arose in a very warm environment. Among the Archaea, all of the Crenarchaeota cultured to date are thermophiles, and the deepest euryarchaeal branchings are represented exclusively by thermophiles. Among the Bacteria, the deepest known branchings are again represented exclusively by thermophiles, and thermophilia is widely scattered throughout the domain. The Archaea comprise a small number of quite disparate phenotypes that grow in unusual niches. All are obligate or facultative anaerobes. All cultured crenarchaeotes are thermophilic, some even growing optimally above the normal boiling temperature of water. The Archaeoglobales are sulfate reducers growing at high temperatures. The extreme halophiles grow only in highly saline environments. The methanogens are confined to a variety of anaerobic niches, often thermophilic. The Bacteria, on the other hand, are notable as being the source of life`s photosynthetic capacity. Five kingdoms of bacteria contain photosynthetic species; and each of the five manifests a distinct type of (chlorophyll-based) photosynthesis.

The Winds of (Evolutionary) Change: Breathing New Life into Microbiology

Science.gov (United States)

Olsen, G. J.; Woese, C. R; Overbeek, R. A.

1996-03-01

To date, over 1500 prokaryotes have been characterized by small subunit rRNA sequencing and molecular phylogeny has had an equally profound effect on our understanding of relationship among eukaryotic microorganisms. The universal phylogenetic tree readily shows however how artificial the strong distinction between the eukaryote and prokaryotes has become. The split between the Archaea and the Bacteria is now recognized as the primary phylogenetic division and that the Eucarya have branched from the same side of the tree as the Archaea. Both prokaryotic domains would seem to be of thermophilic origin suggesting that life arose in a very warm environment. Among the Archaea, all of the Crenarchaeota cultured to date are thermophiles, and the deepest euryarchaeal branchings are represented exclusively by thermophiles. Among the Bacteria, the deepest known branchings are again represented exclusively by thermophiles, and thermophilia is widely scattered throughout the domain. The Archaea comprise a small number of quite disparate phenotypes that grow in unusual niches. All are obligate or facultative anaerobes. All cultured crenarchaeotes are thermophilic, some even growing optimally above the normal boiling temperature of water. The Archaeoglobales are sulfate reducers growing at high temperatures. The extreme halophiles grow only in highly saline environments. The methanogens are confined to a variety of anaerobic niches, often thermophilic. The Bacteria, on the other hand, are notable as being the source of life`s photosynthetic capacity. Five kingdoms of bacteria contain photosynthetic species; and each of the five manifests a distinct type of (chlorophyll-based) photosynthesis.

Dispersal of thermophilic Desulfotomaculum endospores into Baltic Sea sediments over thousands of years

DEFF Research Database (Denmark)

Rezende, Julia Rosa de; Kjeldsen, Kasper Urup; Hubert, Casey RJ

2013-01-01

S rRNA and of the dissimilatory (bi)sulfite reductase (dsrAB) genes within the endospore-forming SRB genus Desulfotomaculum. The thermophilic Desulfotomaculum community in Aarhus Bay sediments consisted of at least 23 species-level 16S rRNA sequence phylotypes. In two cases, pairs of identical 16S r......RNA and dsrAB sequences in Arctic surface sediment 3000km away showed that the same phylotypes are present in both locations. Radiotracer-enhanced most probable number analysis revealed that the abundance of endospores of thermophilic SRB in Aarhus Bay sediment was ca. 104 per cm3 at the surface and decreased...... in water masses preceding sedimentation. The sources of these thermophiles remain enigmatic, but at least one source may be common to both Aarhus Bay and Arctic sediments....

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.

Increased saccharification of kallar grass using ultrafiltrated enzyme from sporrotrichum thermophile

International Nuclear Information System (INIS)

Latif, F.; Rajoka, M.I.; Malik, K.A.

1991-01-01

The local wild type strain of sporotrichum thermophile when grown on untreated lingo cellulose was found to produce a greater level of B-glucosidase component along with other cellulase/xylanase components than most of the reported wild type potent strains. Culture filtrate obtained, when grown on 4% leptochloa fusca (kallar grass) was used as such and after concentration by ultrafiltration technique for saccharification purpose. Concentrated enzymes titre was increased to 1.2 and 4.0 U/ml for Fp-ase and B-glucosidase, respectively. There were losses in the enzyme titre obtained through ultrafiltration possibly due to adsorption on to the ultrafiltration membrane. Enzyme preparations used, saccharifide 5% kallar grass to 70, 55, 75 and 60% (theoretical basis) from cellulases of S. thermophile concentrate, dilute, T. reesei alone and in supplementation with B-glucosidase from A. niger, respectively. Analysis by HPLC revealed slightly higher glucose yield from S. thermophile enzyme preparations, whereas higher level of xylose was attained from T. reesei preparations. Rest of the sugars pooled as Oligo-sugars were found in almost similar concentrations. (author)

Candidatus Nitrosocaldus cavascurensis, an Ammonia Oxidizing, Extremely Thermophilic Archaeon with a Highly Mobile Genome

Directory of Open Access Journals (Sweden)

Sophie S. Abby

2018-01-01

Full Text Available Ammonia oxidizing archaea (AOA of the phylum Thaumarchaeota are widespread in moderate environments but their occurrence and activity has also been demonstrated in hot springs. Here we present the first enrichment of a thermophilic representative with a sequenced genome, which facilitates the search for adaptive strategies and for traits that shape the evolution of Thaumarchaeota. Candidatus Nitrosocaldus cavascurensis has been enriched from a hot spring in Ischia, Italy. It grows optimally at 68°C under chemolithoautotrophic conditions on ammonia or urea converting ammonia stoichiometrically into nitrite with a generation time of approximately 23 h. Phylogenetic analyses based on ribosomal proteins place the organism as a sister group to all known mesophilic AOA. The 1.58 Mb genome of Ca. N. cavascurensis harbors an amoAXCB gene cluster encoding ammonia monooxygenase and genes for a 3-hydroxypropionate/4-hydroxybutyrate pathway for autotrophic carbon fixation, but also genes that indicate potential alternative energy metabolisms. Although a bona fide gene for nitrite reductase is missing, the organism is sensitive to NO-scavenging, underlining the potential importance of this compound for AOA metabolism. Ca. N. cavascurensis is distinct from all other AOA in its gene repertoire for replication, cell division and repair. Its genome has an impressive array of mobile genetic elements and other recently acquired gene sets, including conjugative systems, a provirus, transposons and cell appendages. Some of these elements indicate recent exchange with the environment, whereas others seem to have been domesticated and might convey crucial metabolic traits.

A review of the microbiology of the Rehai geothermal field in Tengchong, Yunnan Province, China

OpenAIRE

Hedlund, Brian P.; Cole, Jessica K.; Williams, Amanda J.; Hou, Weiguo; Zhou, Enmin; Li, Wenjun; Dong, Hailiang

2012-01-01

The Rehai Geothermal Field, located in Tengchong County, in central-western Yunnan Province, is the largest and most intensively studied geothermal field in China. A wide physicochemical diversity of springs (ambient to ∼97 °C; pH from ≤1.8 to ≥9.3) provides a multitude of niches for extremophilic microorganisms. A variety of studies have focused on the cultivation, identification, basic physiology, taxonomy, and biotechnological potential of thermophilic microorganisms from Rehai. Thermophil...

Bacillus coagulans tolerance to 1-ethyl-3-methylimidazolium-based ionic liquids in aqueous and solid-state thermophilic culture.

Science.gov (United States)

Simmons, Christopher W; Reddy, Amitha P; Vandergheynst, Jean S; Simmons, Blake A; Singer, Steven W

2014-01-01

The use of ionic liquids (ILs) to disrupt the recalcitrant structure of lignocellulose and make polysaccharides accessible to hydrolytic enzymes is an emerging technology for biomass pretreatment in lignocellulosic biofuel production. Despite efforts to reclaim and recycle IL from pretreated biomass, residual IL can be inhibitory to microorganisms used for downstream fermentation. As a result, pathways for IL tolerance are needed to improve the activity of fermentative organisms in the presence of IL. In this study, microbial communities from compost were cultured under high-solids and thermophilic conditions in the presence of 1-ethyl-3-methylimidazolium-based ILs to enrich for IL-tolerant microorganisms. A strain of Bacillus coagulans isolated from an IL-tolerant community was grown in liquid and solid-state culture in the presence of the ILs 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) or 1-ethyl-3-methylimidazolium chloride ([C2mim][Cl]) to gauge IL tolerance. Viability and respiration varied with the concentration of IL applied and the type of IL used. B. coagulans maintained growth and respiration in the presence of 4 wt% IL, a concentration similar to that present on IL-pretreated biomass. In the presence of both [C2mim][OAc] and [C2mim][Cl] in liquid culture, B. coagulans grew at a rate approximately half that observed in the absence of IL. However, in solid-state culture, the bacteria were significantly more tolerant to [C2mim][Cl] compared with [C2mim][OAc]. B. coagulans tolerance to IL under industrially relevant conditions makes it a promising bacterium for understanding mechanisms of IL tolerance and discovering IL tolerance pathways for use in other microorganisms, particularly those used in bioconversion of IL-pretreated plant biomass. © 2013 American Institute of Chemical Engineers.

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

International Nuclear Information System (INIS)

Yein, F.S.; Stenesh, J.

1989-01-01

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

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

Acclimatization Study for Biohydrogen Production from Palm Oil Mill Effluent (POME) in Continuous-flow System

Science.gov (United States)

Idris, N.; Lutpi, N. A.; Wong, Y. S.; Tengku Izhar, T. N.

2018-03-01

This research aims to study the acclimatization phase for biohydrogen production from palm oil mill effluent (POME) by adapting the microorganism to the new environment in continuous-flow system of thermophilic bioreactor. The thermophilic fermentation was continuously loaded with 0.4 L/day of raw POME for 35 days to acclimatize the microorganism until a steady state of biohydrogen production was obtained. The significance effect of acclimatization phase on parameter such as pH, microbial growth, chemical oxygen demand (COD), and alkalinity were also studied besides the production of biogas. This study had found that the thermophilic bioreactor reach its steady state with 1960 mL/d of biogas produced, which consist of 894 ppm of hydrogen composition.

Up-Streaming Process for Glucose Oxidase by Thermophilic Penicillium sp. in Shake Flask

OpenAIRE

Muhammad Mohsin JAVED; Aroosh SHABIR; Sana ZAHOOR; Ikram UL-HAQ

2012-01-01

The present study is concerned with the production of glucose oxidase (GOD) from thermophilic Penicillium sp. in 250 mL shake flask. Fourteen different strains of thermophilic Penicillium sp. were isolated from the soil and were screened for glucose oxidase production. IIBP-13 strain gave maximum extra-cellular glucose oxidase production as compared to other isolates. Effect of submerged fermentation in shaking and static conditions, different carbon sources and incubation period on the produ...

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.

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.

Electrode Cultivation and Interfacial Electron Transport in Subsurface Microorganisms

Science.gov (United States)

Karbelkar, A. A.; Jangir, Y.; Reese, B. K.; Wanger, G.; Anderson, C.; El-Naggar, M.; Amend, J.

2016-12-01

characterization of isolated strains can help us establish the possible mechanisms of EET, and hence provide an insight on survival strategies of subsurface microbiota in extreme environments. Continental subsurface environments can present significant energetic challenges to the resident microorganisms. While these environments are geologically diverse, potentially allowing energy harvesting by microorganisms that catalyze redox reactions, many of the abundant electron donors and acceptors are insoluble and therefore not directly bioavailable. Microbes can use extracellular electron transfer (EET) as a metabolic strategy to interact with redox active surfaces. This process can be mimicked on electrode surfaces and hence can lead to enrichment and quantification of subsurface microorganisms A primary bioelectrochemical enrichment with different oxidizing and reducing potentials set up in a single bioreactor was applied in situ to subsurface microorganisms residing in iron oxide rich deposits in the Sanford Underground Research Facility. Secondary enrichment revealed a plethora of classified and unclassified subsurface microbiota on both oxidizing and reducing potentials. From this enrichment, we have isolated a Gram-positive Bacillus along with Gram-negative Cupriavidus and Anaerospora strains (as electrode reducers) and Comamonas (as an electrode oxidizer). The Bacillus and Comamonas isolates were subjected to a detailed electrochemical characterization in half-reactors at anodic and cathodic potentials, respectively. An increase in cathodic current upon inoculation and cyclic voltammetry measurements confirm the hypothesis that Comamonas is capable of electron uptake from electrodes. In addition, measurements of Bacillus on anodes hint towards novel mechanisms that allow EET from Gram-positive bacteria. This study suggests that electrochemical approaches are well positioned to dissect such extracellular interactions that may be prevalent in the subsurface, while using physical

Spore-Forming Thermophilic Bacterium within Artificial Meteorite Survives Entry into the Earth's Atmosphere on FOTON-M4 Satellite Landing Module.

Science.gov (United States)

Slobodkin, Alexander; Gavrilov, Sergey; Ionov, Victor; Iliyin, Vyacheslav

2015-01-01

One of the key conditions of the lithopanspermia hypothesis is that microorganisms situated within meteorites could survive hypervelocity entry from space through the Earth's atmosphere. So far, all experimental proof of this possibility has been based on tests with sounding rockets which do not reach the transit velocities of natural meteorites. We explored the survival of the spore-forming thermophilic anaerobic bacterium, Thermoanaerobacter siderophilus, placed within 1.4-cm thick basalt discs fixed on the exterior of a space capsule (the METEORITE experiment on the FOTON-M4 satellite). After 45 days of orbital flight, the landing module of the space vehicle returned to Earth. The temperature during the atmospheric transit was high enough to melt the surface of basalt. T. siderophilus survived the entry; viable cells were recovered from 4 of 24 wells loaded with this microorganism. The identity of the strain was confirmed by 16S rRNA gene sequence and physiological tests. This is the first report on the survival of a lifeform within an artificial meteorite after entry from space orbit through Earth's atmosphere at a velocity that closely approached the velocities of natural meteorites. The characteristics of the artificial meteorite and the living object applied in this study can serve as positive controls in further experiments on testing of different organisms and conditions of interplanetary transport.

Spore-Forming Thermophilic Bacterium within Artificial Meteorite Survives Entry into the Earth's Atmosphere on FOTON-M4 Satellite Landing Module.

Directory of Open Access Journals (Sweden)

Alexander Slobodkin

Full Text Available One of the key conditions of the lithopanspermia hypothesis is that microorganisms situated within meteorites could survive hypervelocity entry from space through the Earth's atmosphere. So far, all experimental proof of this possibility has been based on tests with sounding rockets which do not reach the transit velocities of natural meteorites. We explored the survival of the spore-forming thermophilic anaerobic bacterium, Thermoanaerobacter siderophilus, placed within 1.4-cm thick basalt discs fixed on the exterior of a space capsule (the METEORITE experiment on the FOTON-M4 satellite. After 45 days of orbital flight, the landing module of the space vehicle returned to Earth. The temperature during the atmospheric transit was high enough to melt the surface of basalt. T. siderophilus survived the entry; viable cells were recovered from 4 of 24 wells loaded with this microorganism. The identity of the strain was confirmed by 16S rRNA gene sequence and physiological tests. This is the first report on the survival of a lifeform within an artificial meteorite after entry from space orbit through Earth's atmosphere at a velocity that closely approached the velocities of natural meteorites. The characteristics of the artificial meteorite and the living object applied in this study can serve as positive controls in further experiments on testing of different organisms and conditions of interplanetary transport.

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...

Turbulence from a microorganism's perspective: Does the open ocean feel different than a coral reef?

Science.gov (United States)

Pepper, Rachel; Variano, Evan; Koehl, M. A. R.

2012-11-01

Microorganisms in the ocean live in turbulent flows. Swimming microorganisms navigate through the water (e.g. larvae land on suitable substrata, predators find patches of prey), but the mechanisms by which they do so in turbulent flow are poorly understood as are the roles of passive transport versus active behaviors. Because microorganisms are smaller than the Kolmagorov length (the smallest scale of eddies in turbulent flow), they experience turbulence as a series of linear gradients in the velocity that vary in time. While the average strength of these gradients and a timescale can be computed from some typical characteristics of the flow, such as the turbulent kinetic energy or the dissipation rate, there are indications that organisms are disproportionally affected by rare, extreme events. Understanding the frequency of such events in different environments will be critical to understanding how microorganisms respond to and navigate in turbulence. To understand the hydrodynamic cues that microorganisms experience in the ocean we must measure velocity gradients in realistic turbulent flow on the spatial and temporal scales encountered by microorganisms. We have been exploring the effect of the spatial resolution of PIV and DNS of turbulent flow on the presence of velocity gradients of different magnitudes at the scale of microorganisms. Here we present some results of PIV taken at different resolutions in turbulent flow over rough biological substrata to illustrate the challenges of quantifying the fluctuations in velocity gradients encountered by aquatic microorganisms.

Research on heavy oil degradation by four thermophilic bacterial strains

Energy Technology Data Exchange (ETDEWEB)

Bao, M.; Chen, Q.; Liu, Z.; Li, Y. [Ocean Univ. of China, Qingdao, Shandong (China)

2009-07-01

The Shengli oilfield is the second largest onshore oil field in China, with a crude oil output of approximately 30 million tons per year. The large quantities of wastewater that are produced during thermal recovery methods have posed a challenge in terms of water reuse, reinjection and discharge. The important aspect of wastewater treatment is the removal of residual heavy oil. Biological methods are considered to be efficient in solving this problem. This paper reported on a study in which 4 thermophilic microorganisms which had the ability to biodegrade heavy oil were screened from heavy oil wastewater in the Shengli oilfield. Their degradation to heavy oil was discussed and the suitable biodegradation conditions of these bacteria were investigated. The study showed that the degrading efficiency of heavy oil by the 4 bacteria was up to 42.0, 47.6, 55.6 and 43.4 per cent in the wastewater which contained 500 mg per litre of heavy oil, respectively. The crude oil samples were analyzed using gas chromatography/flame ionization detection (GC/FID) and gas chromatography/mass spectrometry (GC/MS) before and after degradation. The single 4 strains demonstrated strong biodegradability to normal alkanes and aromatics, and the average degrading efficiency was about 50 and 35 per cent. The degrading efficiency of the mixed 4 strains was better than the single ones, particularly for the poor biodegradable hydrocarbons such as phenanthrenes and fluorines. 21 refs., 2 tabs., 17 figs.

Biohydrogen production from glucose in upflow biofilm reactors with plastic carriers under extreme thermophilic conditions (70(degree)C)

DEFF Research Database (Denmark)

Zheng, H.; Zeng, Raymond Jianxiong; Angelidaki, Irini

2008-01-01

Biohydrogen could efficiently be produced in glucose-fed biofilm reactors filled with plastic carriers and operated at 70°C. Batch experiments were, in addition, conducted to enrich and cultivate glucose-fed extremethermophilic hydrogen producing microorganisms from a biohydrogen CSTR reactor fed...

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.

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

Energy Technology Data Exchange (ETDEWEB)

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

2007-05-15

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

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

Science.gov (United States)

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

2013-06-01

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

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...

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.

Isolation of thermophilic Desulfotomaculum strains with methanol and sulphite from solfataric mud pools, and characterization of Desulfotomaculum solfataricum

NARCIS (Netherlands)

Goorissen, H.P.; Stams, A.J.M.; Hansen, T.A.

2003-01-01

Four strains of thermophilic, endospore-forming, sulfate-reducing bacteria were enriched and isolated from hot solfataric fields in the Krafla area of north-east Iceland, using methanol and sulfite as substrates. Morphologically, these strains resembled thermophilic Desulfotomaculum species. The

Low Biotoxicity of Mars Analog Soils Suggests that the Surface of Mars May be Habitable for Terrestrial Microorganisms

Science.gov (United States)

Schuerger, A. C.; Ming, Douglas W.; Golden, D. C.

2012-01-01

Recent studies on the interactive effects of hypobaria, low temperatures, and CO2-enriched anoxic atmospheres on the growth of 37 species of mesophilic bacteria identified 14 potential biocidal agents that might affect microbial survival and growth on the martian surface. Biocidal or inhibitory factors include (not in priority): (1) solar UV irradiation, (2) low pressure, (3) extreme desiccating conditions, (4) extreme diurnal temperature fluctuations, (5) solar particle events, (6) galactic cosmic rays, (7) UV-glow discharge from blowing dust, (8) solar UV-induced volatile oxidants [e.g., O2(-), O(-), H2O2, O3], (9) globally distributed oxidizing soils, (10) extremely high salts levels [e.g., MgCl2, NaCl, FeSO4, and MgSO4] in surficial soils at some sites on Mars, (11) high concentrations of heavy metals in martian soils, (12) likely acidic conditions in martian fines, (13) high CO2 concentrations in the global atmosphere, and (14) perchlorate-rich soils. Despite these extreme conditions several studies have demonstrated that dormant spores or vegetative cells of terrestrial microorganisms can survive simulated martian conditions as long as they are protected from UV irradiation. What has not been explored in depth are the effects of potential biotoxic geochemical components of the martian regolith on the survival and growth of microorganisms. The primary objectives of the research included: (1) prepare and characterize Mars analog soils amended with potential biotoxic levels of sulfates, salts, acidifying minerals, etc.; and (2) use the simulants to conduct biotoxicity assays to determine if terrestrial microorganisms from spacecraft can survive direct exposure to the analog soils.

Energetic and hydrogen limitations of thermophilic and hyperthermophilic methanogens

Science.gov (United States)

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

2013-12-01

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

The effect of adhesion on survival and growth of microorganisms

International Nuclear Information System (INIS)

Bar-Or, Y.

1990-01-01

Adhesion of microorganisms to solid surfaces or water/air interfaces can significantly influence cellular metabolic activity, development and viability. Attachment is of advantage particularly for organisms growing under oligotrophic or otherwise extreme conditions. However, the ability to detach and migrate is of vital importance when prevailing conditions become too harsh or in situations of population explosion. Adhesion can cause alterations in the physical and chemical properties of substratum surfaces as well, by means of degradation, aggregation, emulsification etc. (author) 48 refs

Direct bioconversion of brown algae into ethanol by thermophilic bacterium Defluviitalea phaphyphila.

Science.gov (United States)

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

2016-01-01

Brown algae are promising feedstocks for biofuel production with inherent advantages of no structural lignin, high growth rate, and no competition for land and fresh water. However, it is difficult for one microorganism to convert all components of brown algae with different oxidoreduction potentials to ethanol. Defluviitalea phaphyphila Alg1 is the first characterized thermophilic bacterium capable of direct utilization of brown algae. Defluviitalea phaphyphila Alg1 can simultaneously utilize mannitol, glucose, and alginate to produce ethanol, and high ethanol yields of 0.47 g/g-mannitol, 0.44 g/g-glucose, and 0.3 g/g-alginate were obtained. A rational redox balance system under obligate anaerobic condition in fermenting brown algae was revealed in D. phaphyphila Alg1 through genome and redox analysis. The excess reducing equivalents produced from mannitol metabolism were equilibrated by oxidizing forces from alginate assimilation. Furthermore, D. phaphyphila Alg1 can directly utilize unpretreated kelp powder, and 10 g/L of ethanol was accumulated within 72 h with an ethanol yield of 0.25 g/g-kelp. Microscopic observation further demonstrated the deconstruction process of brown algae cell by D. phaphyphila Alg1. The integrated biomass deconstruction system of D. phaphyphila Alg1, as well as its high ethanol yield, provided us an excellent alternative for brown algae bioconversion at elevated temperature.

Chlorophyll a with a farnesyl tail in thermophilic cyanobacteria.

Science.gov (United States)

Wiwczar, Jessica M; LaFountain, Amy M; Wang, Jimin; Frank, Harry A; Brudvig, Gary W

2017-11-01

Photosystem II (PSII) of oxygenic photosynthetic organisms normally contains exclusively chlorophyll a (Chl a) as its major light-harvesting pigment. Chl a canonically consists of the chlorin headgroup with a 20-carbon, 4-isoprene unit, phytyl tail. We have examined the 1.9 Å crystal structure of PSII from thermophilic cyanobacteria reported by Shen and coworkers in 2012 (PDB accession of 3ARC/3WU2). A newly refined electron density map from this structure, presented here, reveals that some assignments of the cofactors may be different from those modeled in the 3ARC/3WU2 structure, including a specific Chl a that appears to have a truncated tail by one isoprene unit. We provide experimental evidence using high-performance liquid chromatography and mass spectrometry for a small population of Chl a esterified to a 15-carbon farnesyl tail in PSII of thermophilic cyanobacteria.

Biological effects of extreme environmental conditions. [considering limits of biosphere

Science.gov (United States)

Imshenetskiy, A. A.

1975-01-01

Actions of extreme physical and chemical space factors on microorganisms and plants are elaborated in order to establish limits for the biosphere. Considered are effects of low and high temperatures; ionizing and ultraviolet radiation; various gases; and effects of vibration, desiccation and acceleration.

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...

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...

Extreme genomes

OpenAIRE

DeLong, Edward F

2000-01-01

The complete genome sequence of Thermoplasma acidophilum, an acid- and heat-loving archaeon, has recently been reported. Comparative genomic analysis of this 'extremophile' is providing new insights into the metabolic machinery, ecology and evolution of thermophilic archaea.

Environmental parameters altered by climate change affect the activity of soil microorganisms involved in bioremediation.

Science.gov (United States)

Alkorta, Itziar; Epelde, Lur; Garbisu, Carlos

2017-10-16

Bioremediation, based on the use of microorganisms to break down pollutants, can be very effective at reducing soil pollution. But the climate change we are now experiencing is bound to have an impact on bioremediation performance, since the activity and degrading abilities of soil microorganisms are dependent on a series of environmental parameters that are themselves being altered by climate change, such as soil temperature, moisture, amount of root exudates, etc. Many climate-induced effects on soil microorganisms occur indirectly through changes in plant growth and physiology derived from increased atmospheric CO2 concentrations and temperatures, the alteration of precipitation patterns, etc., with a concomitant effect on rhizoremediation performance (i.e. the plant-assisted microbial degradation of pollutants in the rhizosphere). But these effects are extremely complex and mediated by processes such as acclimation and adaptation. Besides, soil microorganisms form complex networks of interactions with a myriad of organisms from many taxonomic groups that will also be affected by climate change, further complicating data interpretation. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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

Science.gov (United States)

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

2018-05-23

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

Thermophillic and thermotolerant fungi isolated from the thermal effluent of nuclear power generating reactors

International Nuclear Information System (INIS)

Rippon, J.W.; Gerhold, R.; Heath, M.

1980-01-01

Over a period of a year, samples of water, foam, microbial mat, soil and air were obtained from areas associated with the cooling canal of a nuclear power station. The seventeen sample sites included water in the cooling canal that was thermally enriched and soil and water adjacent to, up-stream, downstream and at a distance from the generator. Air samples were taken at the plant and at various disstances from the plant. Fifty-two species of thermotolerant and thermophilic fungi were isolated. Of these, eleven species are grouped as opportunistic Mucorales or opportunistic Aspergillus sp. One veterinary pathogen was also isolated (Dactylaria gallopara). The opportunistic/pathogenic fungi were found primarily in the intake bay, the discharge bay and the cooling canal. Smaller numbers were obtained at both upstream and downstream locations. Soil samples near the cooling canal reflected an enrichment of thermophilous organisms, the previously mentioned opportunistic Mucorales and Aspergillus spp. Their numbers were found to be greater than that usually encountered in a mesophilic environment. However, air and soil samples taken at various distances from the power station indicated no greater abundance of these thermophilous fungi than would be expected from a thermal enriched environment. Our results indicate that there was no significant dissemination of thermophilous fungi from the thermal enriched effluents to the adjacent environment. These findings are consistent with the results of other investigators. (orig.)

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.

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.

Investigation of factors influencing biogas production in a large-scale thermophilic municipal biogas plant

Energy Technology Data Exchange (ETDEWEB)

Weiss, Agnes; Jerome, Valerie; Freitag, Ruth [Bayreuth Univ. (Germany). Chair for Process Biotechnology; Burghardt, Diana; Likke, Likke; Peiffer, Stefan [Bayreuth Univ. (Germany). Dept. of Hydrology; Hofstetter, Eugen M. [RVT Process Equipment GmbH, Steinwiesen (Germany); Gabler, Ralf [BKW Biokraftwerke Fuerstenwalde GmbH, Fuerstenwalde (Germany)

2009-10-15

A continuously operated, thermophilic, municipal biogas plant was observed over 26 months (sampling twice per month) in regard to a number of physicochemical parameters and the biogas production. Biogas yields were put in correlation to parameters such as the volatile fatty acid concentration, the pH and the ammonium concentration. When the residing microbiota was classified via analysis of the 16S rRNA genes, most bacterial sequences matched with unidentified or uncultured bacteria from similar habitats. Of the archaeal sequences, 78.4% were identified as belonging to the genus Methanoculleus, which has not previously been reported for biogas plants, but is known to efficiently use H{sub 2} and CO{sub 2} produced by the degradation of fatty acids by syntrophic microorganisms. In order to further investigate the influence of varied amounts of ammonia (2-8 g/L) and volatile fatty acids on biogas production and composition (methane/CO{sub 2}), laboratory scale satellite experiments were performed in parallel to the technical plant. Finally, ammonia stripping of the process water of the technical plant was accomplished, a measure through which the ammonia entering the biogas reactor via the mash could be nearly halved, which increased the energy output of the biogas plant by almost 20%. (orig.)

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)

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.

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

Science.gov (United States)

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

2016-11-01

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

A comparison of two xylanases from the thermophilic fungi Thielavia terrestris and Thermoascus crustaceus

Energy Technology Data Exchange (ETDEWEB)

Gilbert, M [Ottawa Univ., Dept. of Biology, ON (Canada); Yaguchi, M [Inst. for Biological Sciences, National Research Council of Canada, Ottawa, ON (Canada); Watson, D C [Inst. for Biological Sciences, National Research Council of Canada, Ottawa, ON (Canada); Wong, K K.Y. [Chair of Forest Products Biotechnology, Faculty of Forestry, British Columbia Univ., Vancouver, BC (Canada); Breuil, C [Chair of Forest Products Biotechnology, Faculty of Forestry, British Columbia Univ., Vancouver, BC (Canada); Saddler, J N [Chair of Forest Products Biotechnology, Faculty of Forestry, British Columbia Univ., Vancouver, BC (Canada)

1993-12-01

Two thermophilic xylanases (xylanase II from Thielavia terrestris 255B and the 32-kDa xylanase from Thermoascus crustaceus 235E) were studied to determine if they had different and complementary modes of action when they hydrolysed various types of xylans. Partial amino acid sequencing showed that these two enzymes belonged to different families of [beta]-1,4-glycanases. Xylanase II achieved faster solubilization of insoluble xylan whereas the 32-kDa xylanase was more effective in producing xylose and short xylooligomers. An assessment of the combined hydrolytic action of the two xylanases did not reveal any co-operative action. The sugars released when the two thermophilic xylanases were used together were almost identical to those released when the 32-kDa xylanase acted alone. The two xyalanses were able to remove about 12% of the xylan remaining in an aspen kraft pulp. This indicated that either one of these thermophilic enzymes may be useful for enhancing the bleaching of kraft pulps. (orig.)

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

International Nuclear Information System (INIS)

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

2008-01-01

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

Necromass as a source of energy to microorganisms in marine sediments.

Science.gov (United States)

Bradley, J.; Amend, J.; LaRowe, D.

2017-12-01

Marine sediments constitute one of the largest, most energy-limited biospheres on Earth. Despite increasing exploration and interest characterizing microbial communities in marine sediments, the production and role of microbial dead-matter (necromass) has largely been overlooked. Necromass is produced on a global scale, yet its significance as a power source to heterotrophic microorganisms remains unknown. We developed a physical, bio-energetic and geochemical model to quantify the total power supply from necromass oxidation and the total power demand of living microorganisms in marine sediments. This model is first applied to sediments from the oligotrophic South Pacific Gyre (SPG), where organic carbon and biomass concentrations are extremely low, yet microorganisms persist for millions of years in some of the lowest energy states on Earth. We show that necromass does not supply sufficient power to support the total demands of the living community (maintenance demands of microorganisms in marine sediments for up to 60,000 years following burial. Our model assumes that all counted cells are viable. Yet, if only a fraction of counted cells are alive, the role of necromass as an electron donor in fueling microbial metabolisms is even greater. This new insight requires a reassessment of carbon fluxes in the deep biosphere. By extension, we also demonstrate a mechanism for microbial communities to persist by oxidizing necromass over geological timescales, and thereby endure unfavorable, low-energy settings that might be analogous to conditions on early Earth and on other planetary bodies.

Gas Fermentation using Thermophilic Moorella Species for production of Biochemicals

DEFF Research Database (Denmark)

Redl, Stephanie Maria Anna

Gas fermentation is a promising technology which gained increasing attention over the last years. In this process, acetogenic bacteria convert gases rich in H2, CO2, and CO, into compounds of higher value. The gas can derive from industrial off-gas or from waste streams via gasification. In the gas...... fermentation processes that are nearly on commercial level, mesophilic acetogens are used to mainly produce ethanol and butanediol. However, thermophilic acetogens, such as Moorella thermoacetica would allow for easy downstream processing when producing volatile products such as acetone. This thesis starts...... with a review of the feedstock potential for gas fermentation and how thermophilic production strains as well as unconventional fermentation processes such as mixotrophy can help to exploit this potential. I analyzed a process with respect to thermodynamic and economic considerations, in which acetone...

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

Science.gov (United States)

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

2011-03-01

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

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

Directory of Open Access Journals (Sweden)

Sonia Y Lam

2011-03-01

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

DHAP-dependent aldolases from (hyper)thermophiles: biochemistry and applications

NARCIS (Netherlands)

Falcicchio, P.; Wolterink-van Loo, S.; Franssen, M.C.R.; Oost, van der J.

2014-01-01

Generating new carbon-carbon (C-C) bonds in an enantioselective way is one of the big challenges in organic synthesis. Aldolases are a natural tool for stereoselective C-C bond formation in a green and sustainable way. This review will focus on thermophilic aldolases in general and on

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

Extreme Ionizing-Radiation-Resistant Bacterium

Science.gov (United States)

Vaishampayan, Parag A.; Venkateswaran, Kasthuri J.; Schwendner, Petra

2013-01-01

There is a growing concern that desiccation and extreme radiation-resistant, non-spore-forming microorganisms associated with spacecraft surfaces can withstand space environmental conditions and subsequent proliferation on another solar body. Such forward contamination would jeopardize future life detection or sample return technologies. The prime focus of NASA s planetary protection efforts is the development of strategies for inactivating resistance-bearing micro-organisms. Eradi cation techniques can be designed to target resistance-conferring microbial populations by first identifying and understanding their physiologic and biochemical capabilities that confers its elevated tolerance (as is being studied in Deinococcus phoenicis, as a result of this description). Furthermore, hospitals, food, and government agencies frequently use biological indicators to ensure the efficacy of a wide range of radiation-based sterilization processes. Due to their resistance to a variety of perturbations, the nonspore forming D. phoenicis may be a more appropriate biological indicator than those currently in use. The high flux of cosmic rays during space travel and onto the unshielded surface of Mars poses a significant hazard to the survival of microbial life. Thus, radiation-resistant microorganisms are of particular concern that can survive extreme radiation, desiccation, and low temperatures experienced during space travel. Spore-forming bacteria, a common inhabitant of spacecraft assembly facilities, are known to tolerate these extreme conditions. Since the Viking era, spores have been utilized to assess the degree and level of microbiological contamination on spacecraft and their associated spacecraft assembly facilities. Members of the non-sporeforming bacterial community such as Deinococcus radiodurans can survive acute exposures to ionizing radiation (5 kGy), ultraviolet light (1 kJ/m2), and desiccation (years). These resistive phenotypes of Deinococcus enhance the

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.

Thermophilic archaeal enzymes and applications in biocatalysis.

Science.gov (United States)

Littlechild, Jennifer A

2011-01-01

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

Genetic technologies for extremely thermophilic microorganisms of Sulfolobus, the only genetically tractable genus of crenarchaea

DEFF Research Database (Denmark)

Peng, Nan; Han, Wenyuan; Li, Yingjun

2017-01-01

Archaea represents the third domain of life, with the information-processing machineries more closely resembling those of eukaryotes than the machineries of the bacterial counterparts but sharing metabolic pathways with organisms of Bacteria, the sister prokaryotic phylum. Archaeal organisms also...

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.

Survival and Adaptation of the Thermophilic Species Geobacillus thermantarcticus in Simulated Spatial Conditions

Science.gov (United States)

Di Donato, Paola; Romano, Ida; Mastascusa, Vincenza; Poli, Annarita; Orlando, Pierangelo; Pugliese, Mariagabriella; Nicolaus, Barbara

2018-03-01

Astrobiology studies the origin and evolution of life on Earth and in the universe. According to the panspermia theory, life on Earth could have emerged from bacterial species transported by meteorites, that were able to adapt and proliferate on our planet. Therefore, the study of extremophiles, i.e. bacterial species able to live in extreme terrestrial environments, can be relevant to Astrobiology studies. In this work we described the ability of the thermophilic species Geobacillus thermantarcticus to survive after exposition to simulated spatial conditions including temperature's variation, desiccation, X-rays and UVC irradiation. The response to the exposition to the space conditions was assessed at a molecular level by studying the changes in the morphology, the lipid and protein patterns, the nucleic acids. G. thermantarcticus survived to the exposition to all the stressing conditions examined, since it was able to restart cellular growth in comparable levels to control experiments carried out in the optimal growth conditions. Survival was elicited by changing proteins and lipids distribution, and by protecting the DNA's integrity.

THE EXTREMELY HALOPHILIC MICROORGANISMS, A POSSIBLE MODEL FOR LIFE ON OTHER PLANETS

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Sergiu Fendrihan

2017-12-01

Full Text Available Abstract The group of halophilic Archaea was discovered in the beginning of XX th century. They are able to live in more than 2-3 M of sodium chloride concentration that can be found in hypersaline natural lakes, in alkaline saline lakes, in man-made hypersaline mats, in rock salt, in very salted foods, on salted fish, on salted hides, in stromatolites, in saline soils. Their adaptations consist in resistance to high ionic contents with internal accumulation of K ions in order to face high Na ion content from the near environment. They belong to the Halobacteriaceae family. Their adaptation and their resistance to UV radiation and their resistance in oligotrophic conditions in rock salt, apparently over geological times, increase the possibility to find similar microorganisms in the Martian subsurface and in meteorites, and to support the panspermia theory. Some of the research of a working group in this field of activity and their possible uses are shortly reviewed here.

Northern blot analysis to investigate the abundance of microorganisms

International Nuclear Information System (INIS)

Krause, D.O.

2005-01-01

Modern molecular microbial ecology has its origins in the analysis of informative macromolecules. Zuckerkandl and Pauling proposed that certain macromolecules are relatively free from evolutionary pressure and may be considered a molecular document of the evolutionary history of the organism that carries the molecule. In their paper, they proposed that the sequence difference of a molecule is proportional to the evolutionary distance between the organisms; the greater the sequence differences the greater the evolutionary distance. A significant breakthrough with this approach in microbial systematics resulted from the work of Woese and Fox who used oligonucleotide cataloguing of 16S-rRNA to delineate the phylogenetic relationships between microorganisms. By using this approach, it was possible to demonstrate that all life on earth could be divided into three kingdoms: eukarya, procarya and archaea. The unique findings of this research was that the archaea, made up of many methanogenic and thermophilic microorganisms, were probably the most ancient life forms on earth and were not bacteria at all. One of the first applications of rRNA genes was the recovery of unique 5S-rRNA sequences from the Yellowstone hot spring. Even though the statistical utility of the short 5S sequences was limited, it demonstrated that there was a great deal of uncultured diversity within the ecosystem. This uncultured diversity was demonstrated to be highly significant when clone libraries were constructed from the Yellowstone hot spring. Universal PCR primers were used to amplify 16S-rDNA from the microbial community, and these mixed amplicons were cloned into a vector. Each insert, potentially representing a different species, was sequenced giving a snapshot of microbial diversity in the sample. A unique feature of the rRNAs is that they are hierarchical molecules. This means that there are regions where the molecules is highly conserved, others where the sequence is variable, and even

Development of a continuous bioconversion system using a thermophilic whole-cell biocatalyst.

Science.gov (United States)

Ninh, Pham Huynh; Honda, Kohsuke; Yokohigashi, Yukako; Okano, Kenji; Omasa, Takeshi; Ohtake, Hisao

2013-03-01

The heat treatment of recombinant mesophilic cells having heterologous thermophilic enzymes results in the denaturation of indigenous mesophilic enzymes and the elimination of undesired side reactions; therefore, highly selective whole-cell catalysts comparable to purified enzymes can be readily prepared. However, the thermolysis of host cells leads to the heat-induced leakage of thermophilic enzymes, which are produced as soluble proteins, limiting the exploitation of their excellent stability in repeated and continuous reactions. In this study, Escherichia coli cells having the thermophilic fumarase from Thermus thermophilus (TtFTA) were treated with glutaraldehyde to prevent the heat-induced leakage of the enzyme, and the resulting cells were used as a whole-cell catalyst in repeated and continuous reactions. Interestingly, although electron microscopic observations revealed that the cellular structure of glutaraldehyde-treated E. coli was not apparently changed by the heat treatment, the membrane permeability of the heated cells to relatively small molecules (up to at least 3 kDa) was significantly improved. By applying the glutaraldehyde-treated E. coli having TtFTA to a continuous reactor equipped with a cell-separation membrane filter, the enzymatic hydration of fumarate to malate could be operated for more than 600 min with a molar conversion yield of 60% or higher.

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.

The Activity of Cellulase from Thermophilic Fungi Isolated from CaneBagasses

International Nuclear Information System (INIS)

Aris-Toharisman; Akyunul-Jannah

2000-01-01

The activity of cellulase from thermophilic fungi isolated from canebagasses has been measured. This wild strain, named fungal strain PJ-2,secreted a large amount of cellulolytic enzyme components consisting of 0.46units of avicelase, 0.8 units of carboxymethyl cellulose hydrolizing enzyme(CMCase) and 0.5 units of β-glucosidase per ml of culture broth oncultivation in Mandels Reese medium for 7 days at 500 o C. These cellulasesproduction was lower than that of Trichoderma reesei NRRL 3653 producing 0.5units/ml avicelase, 1.6 units/ml CMCase and 0.4 units/ml ofβ-glucosidase cultivated in the same medium at 30 o C. However,thermophilic fungi may be potential to be exploited in lignocellulosedegradation at the tropical areas as the process usually needs temperature ofabove 50 o C. (author)

Diversity, biological roles and biosynthetic pathways for sugar-glycerate containing compatible solutes in bacteria and archaea.

Science.gov (United States)

Empadinhas, Nuno; da Costa, Milton S

2011-08-01

A decade ago the compatible solutes mannosylglycerate (MG) and glucosylglycerate (GG) were considered to be rare in nature. Apart from two species of thermophilic bacteria, Thermus thermophilus and Rhodothermus marinus, and a restricted group of hyperthermophilic archaea, the Thermococcales, MG had only been identified in a few red algae. Glucosylglycerate was considered to be even rarer and had only been detected as an insignificant solute in two halophilic microorganisms, a cyanobacterium, as a component of a polysaccharide and of a glycolipid in two actinobacteria. Unlike the hyper/thermophilic MG-accumulating microorganisms, branching close to the root of the Tree of Life, those harbouring GG shared a mesophilic lifestyle. Exceptionally, the thermophilic bacterium Persephonella marina was reported to accumulate GG. However, and especially owing to the identification of the key-genes for MG and GG synthesis and to the escalating numbers of genomes available, a plethora of new organisms with the resources to synthesize these solutes has been recognized. The accumulation of GG as an 'emergency' compatible solute under combined salt stress and nitrogen-deficient conditions now seems to be a disseminated survival strategy from enterobacteria to marine cyanobacteria. In contrast, the thermophilic and extremely radiation-resistant bacterium Rubrobacter xylanophilus is the only actinobacterium known to accumulate MG, and under all growth conditions tested. This review addresses the environmental factors underlying the accumulation of MG, GG and derivatives in bacteria and archaea and their roles during stress adaptation or as precursors for more elaborated macromolecules. The diversity of pathways for MG and GG synthesis as well as those for some of their derivatives is also discussed. The importance of glycerate-derived organic solutes in the microbial world is only now being recognized. Their stress-dependent accumulation and the molecular aspects of their

Metagenome reveals potential microbial degradation of hydrocarbon coupled with sulfate reduction in an oil-immersed chimney from Guaymas Basin

Directory of Open Access Journals (Sweden)

Ying eHe

2013-06-01

Full Text Available Deep-sea hydrothermal vent chimneys contain a high diversity of microorganisms, yet the metabolic activity and the ecological functions of the microbial communities remain largely unexplored. In this study, a metagenomic approach was applied to characterize the metabolic potential in a Guaymas hydrothermal vent chimney and to conduct comparative genomic analysis among a variety of environments with sequenced metagenomes. Complete clustering of functional gene categories with a comparative metagenomic approach showed that this Guaymas chimney metagenome was clustered most closely with a chimney metagenome from Juan de Fuca. All chimney samples were enriched with genes involved in recombination and repair, chemotaxis and flagellar assembly, highlighting their roles in coping with the fluctuating extreme deep-sea environments. A high proportion of transposases was observed in all the metagenomes from deep-sea chimneys, supporting the previous hypothesis that horizontal gene transfer may be common in the deep-sea vent chimney biosphere. In the Guaymas chimney metagenome, thermophilic sulfate reducing microorganisms including bacteria and archaea were found predominant, and genes coding for the degradation of refractory organic compounds such as cellulose, lipid, pullullan, as well as a few hydrocarbons including toluene, ethylbenzene and o-xylene were identified. Therefore, this oil-immersed chimney supported a thermophilic microbial community capable of oxidizing a range of hydrocarbons that served as electron donors for sulphate reduction under anaerobic conditions.

Isolation of thermophilic Desulfotomaculum strains with methanol and sulfite from solfataric mud pools, and characterization of Desulfotomaculum solfataficum sp nov

NARCIS (Netherlands)

Goorissen, H.P.; Boschker, H.T.S.; Stams, A.J.M.; Hansen, T.A.

2003-01-01

Four strains of thermophilic, endospore-forming, sulfate-reducing bacteria were enriched and isolated from hot solfataric fields in the Krafla area of north-east Iceland, using methanol and sulfite as substrates. Morphologically, these strains resembled thermophilic Desulfotomaculum species. The

Isolation of thermophilic Desulfotomaculum strains with methanol and sulfite from solfataric mud pools, and characterization of Desulfotomaculum solfataficum sp nov

NARCIS (Netherlands)

Goorissen, HP; Boschker, HTS; Stams, AJM; Hansen, TA

Four strains of thermophilic, endospore-forming, sulfate-reducing bacteria were enriched and isolated from hot solfataric fields in the Krafla area of north-east Iceland, using methanol and sulfite as substrates. Morphologically, these strains resembled thermophilic Desulfotomaculum species. The

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

African Journals Online (AJOL)

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2011-12-05

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

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.).

Bioleaching of metals from electronic scrap by moderately thermophilic acidophilic bacteria

NARCIS (Netherlands)

Ilyas, Sadia; Anwar, Munir A.; Niazi, Shahida B.; Ghauri, M. Afzal

The present work was aimed at studying the bioleachability of metals from electronic scrap by the selected moderately thermophilic strains of acidophilic chemolithotrophic and acidophilic heterotrophic bacteria. These included Sulfobacillus thermosulfidooxidans and an unidentified acidophilic

Space agriculture for habitation on Mars with hyper-thermophilic aerobic composting bacteria

Science.gov (United States)

Space Agriculture Task Force; Ishikawa, Y.; Tomita-Yokotani, K.; Hashimoto, H.; Kitaya, Y.; Yamashita, M.; Nagatomo, M.; Oshima, T.; Wada, H.

Manned Mars exploration, especially for extended periods of time, will require recycle of materials to support human life. Here, a conceptual design is developed for a Martian agricultural system driven by biologically regenerative functions. One of the core biotechnologies function is the use of hyper-thermophilic aerobic composting bacterial ecology. These thermophilic bacteria can play an important role in increasing the effectiveness of the processing of human metabolic waste and inedible biomass and of converting them to fertilizer for the cultivation of plants. This microbial technology has been already well established for the purpose of processing sewage and waste materials for small local communities in Japan. One of the characteristics of the technology is that the metabolic heat release that occurs during bacterial fermentation raises the processing temperature sufficiently high at 80 100 °C to support hyper-thermophilic bacteria. Such a hyper-thermophilic system is found to have great capability of decomposing wastes including even their normally recalcitrant components, in a reasonably short period of time and of providing a better quality of fertilizer as an end-product. High quality compost has been shown to be a key element in creating a healthy regenerative food production system. In ground-based studies, the soil microbial ecology after the addition of high quality compost was shown to improve plant growth and promote a healthy symbiosis of arbuscular mycorrhizal fungi. Another advantage of such high processing temperature is the ability to sterilize the pathogenic organisms through the fermentation process and thus to secure the hygienic safety of the system. Plant cultivation is one of the other major systems. It should fully utilize solar energy received on the Martian surface for supplying energy for photosynthesis. Subsurface water and atmospheric carbon dioxide mined on Mars should be also used in the plant cultivation system. Oxygen and

Biochemical characterization of thermophilic lignocellulose degrading enzymes and their potential for biomass bioprocessing

Energy Technology Data Exchange (ETDEWEB)

Zambare, Vasudeo; Zambare, Archana; Christopher, Lew P. [Center for Bioprocessing Research & Development, South Dakota School of Mines and Technology, Rapid City 57701, SD (United States); Muthukumarappan, Kasiviswanath [Center for Bioprocessing Research & Development, South Dakota State University, Brookings 57007, SD (United States)

2011-07-01

A thermophilic microbial consortium (TMC) producing hydrolytic (cellulolytic and xylanolytic) enzymes was isolated from yard waste compost following enrichment with carboxymethyl cellulose and birchwood xylan. When grown on 5% lignocellulosic substrates (corn stover and prairie cord grass) at 60C, the thermophilic consortium produced more xylanase (up to 489 U/l on corn stover) than cellulase activity (up to 367 U/l on prairie cord grass). Except for the carboxymethyl cellulose-enriched consortium, thermo-mechanical extrusion pretreatment of these substrates had a positive effect on both activities with up to 13% and 21% increase in the xylanase and cellulase production, respectively. The optimum temperatures of the crude cellulase and xylanase were 60C and 70C with half-lives of 15 h and 18 h, respectively, suggesting higher thermostability for the TMC xylanase. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the crude enzyme exhibited protein bands of 25-77 kDa with multiple enzyme activities containing 3 cellulases and 3 xylanases. The substrate specificity declined in the following descending order: avicel>birchwood xylan>microcrystalline cellulose>filter paper>pine wood saw dust>carboxymethyl cellulose. The crude enzyme was 77% more active on insoluble than soluble cellulose. The Km and Vmax values were 36.49 mg/ml and 2.98 U/mg protein on avicel (cellulase), and 22.25 mg/ml and 2.09 U/mg protein, on birchwood xylan (xylanase). A total of 50 TMC isolates were screened for cellulase and xylanase secretion on agar plates. All single isolates showed significantly lower enzyme activities when compared to the thermophilic consortia. This is indicative of the strong synergistic interactions that exist within the thermophilic microbial consortium and enhance its hydrolytic capabilities. It was further demonstrated that the thermostable enzyme-generated lignocellulosic hydrolyzates can be fermented to bioethanol by a recombinant strain of Escherichia coli

Endangerment of thermophilous flora even under conditions of increasing environmental temperatures

Directory of Open Access Journals (Sweden)

Vladimír Růžička

2004-01-01

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

Comparative studies on the production of cellulases by thermophilic fungi in submerged and solid-state fermentation

Energy Technology Data Exchange (ETDEWEB)

Grajek, W

1987-05-01

Six thermophilic fungi were examined for their ability to produce cellulolytic enzymes in liquid (LF) and solid-state fermentation (SSF). The best cellulase activities were achieved by Thermoascus aurantiacus and Sporotrichum thermophile. Taking into consideration that solid-state medium obtained from 100 g of dry sugar-beet pulp occupies about 1 l of fermentor volume equivalent to 1 l of LF, it was confirmed that enzyme productivity per unit volume from both fungi was greater in SSF than in LF. The cellulase system obtained by SSF with T. aurantiacus contained 1.322 IU/l of exo-..beta..-D-glucanase, 53.269 IU/l of endo-..beta..-D-glucanase and 8.974 IU/l of ..beta..-D-glucosidase. The thermal and pH characteristics of cellulases from solid-state fermentation of T. aurantiacus and S. thermophile are described.

Generation of PHB from Spent Sulfite Liquor Using Halophilic Microorganisms.

Science.gov (United States)

Weissgram, Michaela; Gstöttner, Janina; Lorantfy, Bettina; Tenhaken, Raimund; Herwig, Christoph; Weber, Hedda K

2015-06-08

Halophilic microorganisms thrive at elevated concentrations of sodium chloride up to saturation and are capable of growing on a wide variety of carbon sources like various organic acids, hexose and also pentose sugars. Hence, the biotechnological application of these microorganisms can cover many aspects, such as the treatment of hypersaline waste streams of different origin. Due to the fact that the high osmotic pressure of hypersaline environments reduces the risk of contamination, the capacity for cost-effective non-sterile cultivation can make extreme halophilic microorganisms potentially valuable organisms for biotechnological applications. In this contribution, the stepwise use of screening approaches, employing design of experiment (DoE) on model media and subsequently using industrial waste as substrate have been implemented to investigate the applicability of halophiles to generate PHB from the industrial waste stream spent sulfite liquor (SSL). The production of PHB on model media as well as dilutions of industrial substrate in a complex medium has been screened for by fluorescence microscopy using Nile Blue staining. Screening was used to investigate the ability of halophilic microorganisms to withstand the inhibiting substances of the waste stream without negatively affecting PHB production. It could be shown that neither single inhibiting substances nor a mixture thereof inhibited growth in the investigated range, hence, leaving the question on the inhibiting mechanisms open. However, it could be demonstrated that some haloarchaea and halophilic bacteria are able to produce PHB when cultivated on 3.3% w/w dry matter spent sulfite liquor, whereas H. halophila was even able to thrive on 6.6% w/w dry matter spent sulfite liquor and still produce PHB.

High-solids enrichment of thermophilic microbial communities and their enzymes on bioenergy feedstocks

Energy Technology Data Exchange (ETDEWEB)

Reddy, A. P.; Allgaier, M.; Singer, S.W.; Hazen, T.C.; Simmons, B.A.; Hugenholtz, P.; VanderGheynst, J.S.

2011-04-01

Thermophilic microbial communities that are active in a high-solids environment offer great potential for the discovery of industrially relevant enzymes that efficiently deconstruct bioenergy feedstocks. In this study, finished green waste compost was used as an inoculum source to enrich microbial communities and associated enzymes that hydrolyze cellulose and hemicellulose during thermophilic high-solids fermentation of the bioenergy feedstocks switchgrass and corn stover. Methods involving the disruption of enzyme and plant cell wall polysaccharide interactions were developed to recover xylanase and endoglucanase activity from deconstructed solids. Xylanase and endoglucanase activity increased by more than a factor of 5, upon four successive enrichments on switchgrass. Overall, the changes for switchgrass were more pronounced than for corn stover; solids reduction between the first and second enrichments increased by a factor of four for switchgrass while solids reduction remained relatively constant for corn stover. Amplicon pyrosequencing analysis of small-subunit ribosomal RNA genes recovered from enriched samples indicated rapid changes in the microbial communities between the first and second enrichment with the simplified communities achieved by the third enrichment. The results demonstrate a successful approach for enrichment of unique microbial communities and enzymes active in a thermophilic high-solids environment.

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

Pressure stabilization is not a general property of thermophilic enzymes: the adenylate kinases of Methanococcus voltae, Methanococcus maripaludis, Methanococcus thermolithotrophicus, and Methanococcus jannaschii.

OpenAIRE

Konisky, J; Michels, P C; Clark, D S

1995-01-01

The application of 50-MPa pressure did not increase the thermostabilities of adenylate kinases purified from four related mesophilic and thermophilic marine methanogens. Thus, while it has been reported that some thermophilic enzymes are stabilized by pressure (D. J. Hei and D. S. Clark, Appl. Environ. Microbiol. 60:932-939, 1994), hyperbaric stabilization is not an intrinsic property of all enzymes from deep-sea thermophiles.

Effects of Atrazine on Soil Microorganisms

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Ljiljana Radivojević

2006-01-01

Full Text Available Effects of the herbicide atrazine on soil microorganisms was investigated. Trials were set up in laboratory, on a clay loam soil. Atrazine was applied at 8.0, 40.0 and 80.0 mg/kg soil rates. The abundance of total microorganisms, fungi, actinomycetes, cellulolytic microorganisms and amino-heterotrophs was recorded. Soil samples were collected 1, 7, 14, 21, 30 and 60 days after atrazine treatment for microbiological analyses.The results showed that the intensity of atrazine effect on soil microorganisms depended on treatment rate, exposure time and group of microorganisms. Atrazine had an inhibiting effect on cellulolytic microorganisms and amino-heterotrophs. Initially, it inhibited fungiand actinomycetes but its effect turned into a stimulating one once a population recovered. Atrazine had a stimulating effect on total abundance of microorganisms.

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...

Repair of ultraviolet light-induced damage in Micrococcus radiophilus, and extremely resistant microorganism

International Nuclear Information System (INIS)

Lavin, M.F.; Jenkins, A.; Kidson, C.

1976-01-01

Repair of ultraviolet radiation damage was examined in an extremely radioresistant organism, Micrococcus radiophilus. Measurement of the number of thymine-containing dimers formed as a function of ultraviolet dose suggests that the ability of this organism to withstand high doses of ultraviolet radiation (20,000 ergs/mm 2 ) is not related to protective screening by pigments. M. radiophilus carries out a rapid excision of thymine dimers at doses of ultraviolet light up to 10,000 ergs/mm 2 . Synthesis of deoxyribonucleic acid is reduced after irradiation, but after removal of photodamage the rate approaches that in unirradiated cells. A comparison is drawn with Micrococcus luteus and M. radiodurans. We conclude that the extremely high resistance to ultraviolet irradiation in M. radiophilus is at least partly due to the presence of an efficient excision repair system

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...

Large-scale production of diesel-like biofuels - process design as an inherent part of microorganism development.

Science.gov (United States)

Cuellar, Maria C; Heijnen, Joseph J; van der Wielen, Luuk A M

2013-06-01

Industrial biotechnology is playing an important role in the transition to a bio-based economy. Currently, however, industrial implementation is still modest, despite the advances made in microorganism development. Given that the fuels and commodity chemicals sectors are characterized by tight economic margins, we propose to address overall process design and efficiency at the start of bioprocess development. While current microorganism development is targeted at product formation and product yield, addressing process design at the start of bioprocess development means that microorganism selection can also be extended to other critical targets for process technology and process scale implementation, such as enhancing cell separation or increasing cell robustness at operating conditions that favor the overall process. In this paper we follow this approach for the microbial production of diesel-like biofuels. We review current microbial routes with both oleaginous and engineered microorganisms. For the routes leading to extracellular production, we identify the process conditions for large scale operation. The process conditions identified are finally translated to microorganism development targets. We show that microorganism development should be directed at anaerobic production, increasing robustness at extreme process conditions and tailoring cell surface properties. All the same time, novel process configurations integrating fermentation and product recovery, cell reuse and low-cost technologies for product separation are mandatory. This review provides a state-of-the-art summary of the latest challenges in large-scale production of diesel-like biofuels. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bioleaching of multiple metals from contaminated sediment by moderate thermophiles.

Science.gov (United States)

Gan, Min; Jie, Shiqi; Li, Mingming; Zhu, Jianyu; Liu, Xinxing

2015-08-15

A moderately thermophilic consortium was applied in bioleaching multiple metals from contaminated sediment. The consortium got higher acidification and metals soubilization efficiency than that of the pure strains. The synergistic effect of the thermophilic consortium accelerated substrates utilization. The utilization of substrate started with sulfur in the early stage, and then the pH declined, giving rise to making use of the pyrite. Community dynamic showed that A. caldus was the predominant bacteria during the whole bioleaching process while the abundance of S. thermotolerans increased together with pyrite utilization. Solubilization efficiency of Zn, Cu, Mn and Cd reached 98%, 94%, 95%, and 89% respectively, while As, Hg, Pb was only 45%, 34%, 22%. Logistic model was used to simulate the bioleaching process, whose fitting degree was higher than 90%. Correlation analysis revealed that metal leaching was mainly an acid solubilization process. Fraction analysis revealed that metals decreased in mobility and bioavailability. Copyright © 2015 Elsevier Ltd. All rights reserved.

Enzyme dynamics and hydrogen tunnelling in a thermophilic alcohol dehydrogenase

Science.gov (United States)

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

1999-06-01

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

ANAEROBIC BIODEGRADATION OF A BIODEGRADABLE MATERIAL UNDER ANAEROBIC - THERMOPHILIC DIGESTION

Directory of Open Access Journals (Sweden)

RICARDO CAMACHO-MUÑOZ

2014-12-01

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

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.

Thermophilic Dry Methane Fermentation of Distillation Residue Eluted from Ethanol Fermentation of Kitchen Waste and Dynamics of Microbial Communities.

Science.gov (United States)

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

2017-01-01

Thermophilic dry methane fermentation is advantageous for feedstock with high solid content. Distillation residue with 65.1 % moisture content was eluted from ethanol fermentation of kitchen waste and subjected to thermophilic dry methane fermentation, after adjusting the moisture content to 75 %. The effect of carbon to nitrogen (C/N) ratio on thermophilic dry methane fermentation was investigated. Results showed that thermophilic dry methane fermentation could not be stably performed for >10 weeks at a C/N ratio of 12.6 and a volatile total solid (VTS) loading rate of 1 g/kg sludge/d; however, it was stably performed at a C/N ratio of 19.8 and a VTS loading rate of 3 g/kg sludge/d with 83.4 % energy recovery efficiency. Quantitative PCR analysis revealed that the number of bacteria and archaea decreased by two orders of magnitude at a C/N ratio of 12.6, whereas they were not influenced at a C/N ratio of 19.8. Microbial community analysis revealed that the relative abundance of protein-degrading bacteria increased and that of organic acid-oxidizing bacteria and acetic acid-oxidizing bacteria decreased at a C/N ratio of 12.6. Therefore, there was accumulation of NH 4 + and acetic acid, which inhibited thermophilic dry methane fermentation.

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

International Nuclear Information System (INIS)

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

2009-01-01

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

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.

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.

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

Science.gov (United States)

2011-01-01

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

Microorganisms in food technology

Energy Technology Data Exchange (ETDEWEB)

Rose, A H

1981-11-01

Man has been using microorganisms for thousands of years to make bread, cheese, beer, wine, etc. Today, microorganisms can be specially grown or genetically manipulated so as to synthesize high-quality proteins even from low-grade basic materials.

Fossil Microorganisms in Archaean

Science.gov (United States)

Astafleva, Marina; Hoover, Richard; Rozanov, Alexei; Vrevskiy, A.

2006-01-01

Ancient Archean and Proterozoic rocks are the model objects for investigation of rocks comprising astromaterials. The first of Archean fossil microorganisms from Baltic shield have been reported at the last SPIE Conference in 2005. Since this confeence biomorphic structures have been revealed in Archean rocks of Karelia. It was determined that there are 3 types of such bion structures: 1. structures found in situ, in other words microorganisms even-aged with rock matrix, that is real Archean fossils biomorphic structures, that is to say forms inhabited early formed rocks, and 3. younger than Archean-Protherozoic minerali microorganisms, that is later contamination. We made attempt to differentiate these 3 types of findings and tried to understand of burial of microorganisms. The structures belongs (from our point of view) to the first type, or real Archean, forms were under examination. Practical investigation of ancient microorganisms from Green-Stone-Belt of Northern Karelia turns to be very perspective. It shows that even in such ancient time as Archean ancient diverse world existed. Moreover probably such relatively highly organized cyanobacteria and perhaps eukaryotic formes existed in Archean world.

Widespread Disulfide Bonding in Proteins from Thermophilic Archaea

OpenAIRE

Jorda, Julien; Yeates, Todd O.

2011-01-01

Disulfide bonds are generally not used to stabilize proteins in the cytosolic compartments of bacteria or eukaryotic cells, owing to the chemically reducing nature of those environments. In contrast, certain thermophilic archaea use disulfide bonding as a major mechanism for protein stabilization. Here, we provide a current survey of completely sequenced genomes, applying computational methods to estimate the use of disulfide bonding across the Archaea. Microbes belonging to the Crenarchaea...

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

Science.gov (United States)

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

2012-12-15

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

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

Science.gov (United States)

Amend, Jan P.; Plyasunov, Andrey V.

2001-11-01

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

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

Sulfate Transporters in Dissimilatory Sulfate Reducing Microorganisms: A Comparative Genomics Analysis

Directory of Open Access Journals (Sweden)

Angeliki Marietou

2018-03-01

Full Text Available The first step in the sulfate reduction pathway is the transport of sulfate across the cell membrane. This uptake has a major effect on sulfate reduction rates. Much of the information available on sulfate transport was obtained by studies on assimilatory sulfate reduction, where sulfate transporters were identified among several types of protein families. Despite our growing knowledge on the physiology of dissimilatory sulfate-reducing microorganisms (SRM there are no studies identifying the proteins involved in sulfate uptake in members of this ecologically important group of anaerobes. We surveyed the complete genomes of 44 sulfate-reducing bacteria and archaea across six phyla and identified putative sulfate transporter encoding genes from four out of the five surveyed protein families based on homology. We did not find evidence that ABC-type transporters (SulT are involved in the uptake of sulfate in SRM. We speculate that members of the CysP sulfate transporters could play a key role in the uptake of sulfate in thermophilic SRM. Putative CysZ-type sulfate transporters were present in all genomes examined suggesting that this overlooked group of sulfate transporters might play a role in sulfate transport in dissimilatory sulfate reducers alongside SulP. Our in silico analysis highlights several targets for further molecular studies in order to understand this key step in the metabolism of SRMs.

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.

Biosurfactants from marine microorganisms

Directory of Open Access Journals (Sweden)

Suppasil Maneerat

2005-11-01

Full Text Available Biosurfactants are the surface-active molecules synthesized by microorganisms. With the advantage of environmental compatibility, the demand for biosurfactants has been steadily increasing and may eventually replace their chemically synthesized counterparts. Marine biosurfactants produced by some marine microorganisms have been paid more attention, particularly for the bioremediation of the sea polluted by crude oil. This review describes screening of biosurfactant-producing microorganisms, the determination of biosurfactant activity as well as the recovery of marine surfactant. The uses of marine biosurfactants for bioremediation are also discussed.

Assembly and multiple gene expression of thermophilic enzymes in Escherichia coli for in vitro metabolic engineering.

Science.gov (United States)

Ninh, Pham Huynh; Honda, Kohsuke; Sakai, Takaaki; Okano, Kenji; Ohtake, Hisao

2015-01-01

In vitro reconstitution of an artificial metabolic pathway is an emerging approach for the biocatalytic production of industrial chemicals. However, several enzymes have to be separately prepared (and purified) for the construction of an in vitro metabolic pathway, thereby limiting the practical applicability of this approach. In this study, genes encoding the nine thermophilic enzymes involved in a non-ATP-forming chimeric glycolytic pathway were assembled in an artificial operon and co-expressed in a single recombinant Escherichia coli strain. Gene expression levels of the thermophilic enzymes were controlled by their sequential order in the artificial operon. The specific activities of the recombinant enzymes in the cell-free extract of the multiple-gene-expression E. coli were 5.0-1,370 times higher than those in an enzyme cocktail prepared from a mixture of single-gene-expression strains, in each of which a single one of the nine thermophilic enzymes was overproduced. Heat treatment of a crude extract of the multiple-gene-expression cells led to the denaturation of indigenous proteins and one-step preparation of an in vitro synthetic pathway comprising only a limited number of thermotolerant enzymes. Coupling this in vitro pathway with other thermophilic enzymes including the H2 O-forming NADH oxidase or the malate/lactate dehydrogenase facilitated one-pot conversion of glucose to pyruvate or lactate, respectively. © 2014 Wiley Periodicals, Inc.

Thermophilic Bacteria Colony Growwth and its Consequences in the Food Industry

Czech Academy of Sciences Publication Activity Database

Melzoch, K.; Votruba, Jaroslav; Sekavová, B.; Piterková, L.; Rychtera, M.

2004-01-01

Roč. 22, č. 1 (2004), s. 1-8 ISSN 1212-1800 R&D Projects: GA ČR GA525/03/0375 Institutional research plan: CEZ:AV0Z5020903 Keywords : thermophilic bacteria * colony growth Subject RIV: EE - Microbiology, Virology

Identification of Multiple Soluble Fe(III Reductases in Gram-Positive Thermophilic Bacterium Thermoanaerobacter indiensis BSB-33

Directory of Open Access Journals (Sweden)

Subrata Pal

2014-01-01

Full Text Available Thermoanaerobacter indiensis BSB-33 has been earlier shown to reduce Fe(III and Cr(VI anaerobically at 60°C optimally. Further, the Gram-positive thermophilic bacterium contains Cr(VI reduction activity in both the membrane and cytoplasm. The soluble fraction prepared from T. indiensis cells grown at 60°C was found to contain the majority of Fe(III reduction activity of the microorganism and produced four distinct bands in nondenaturing Fe(III reductase activity gel. Proteins from each of these bands were partially purified by chromatography and identified by mass spectrometry (MS with the help of T. indiensis proteome sequences. Two paralogous dihydrolipoamide dehydrogenases (LPDs, thioredoxin reductase (Trx, NADP(H-nitrite reductase (Ntr, and thioredoxin disulfide reductase (Tdr were determined to be responsible for Fe(III reductase activity. Amino acid sequence and three-dimensional (3D structural similarity analyses of the T. indiensis Fe(III reductases were carried out with Cr(VI reducing proteins from other bacteria. The two LPDs and Tdr showed very significant sequence and structural identity, respectively, with Cr(VI reducing dihydrolipoamide dehydrogenase from Thermus scotoductus and thioredoxin disulfide reductase from Desulfovibrio desulfuricans. It appears that in addition to their iron reducing activity T. indiensis LPDs and Tdr are possibly involved in Cr(VI reduction as well.

Seasonal Variability of Thermophilic Campylobacter Spp. in Raw Milk Sold by Automatic Vending Machines in Lombardy Region.

Science.gov (United States)

Bertasi, Barbara; Losio, Marina Nadia; Daminelli, Paolo; Finazzi, Guido; Serraino, Andrea; Piva, Silvia; Giacometti, Federica; Massella, Elisa; Ostanello, Fabio

2016-06-03

In temperate climates, a seasonal trend was observed in the incidence of human campylobacteriosis cases, with peaks reported in spring and autumn in some countries, or in summer in others; a similar trend was observed in Campylobacter spp. dairy cattle faecal shedding, suggesting that cattle may play a role in the seasonal peak of human infection. The objectives of this study were to assess if a seasonal trend in thermophilic Campylobacter spp. contamination of raw milk exists and to evaluate a possible relation between this and the increase of human campylobacteriosis incidence in summer months. The results showed a mean prevalence of 1.6% of milk samples positive for thermophilic Campylobacter spp. with a wide range (0.0-3.1%) in different months during the three years considered. The statistical analysis showed a significant difference (P<0.01) of the prevalence of positive samples for thermophilic Campylobacter spp. between warmer and cooler months (2.3 vs 0.6%). The evidence of a seasonal trend in thermophilic Campylobacter spp. contamination of raw milk sold for direct consumption, with an increase of the prevalence in warmer months, may represent one of the possible links between seasonal trend in cattle faecal shedding and seasonal trend in human campylobacteriosis.

Computer Simulation Study of the Stability Mechanism of Thermophile, MJ0305

Science.gov (United States)

Song, Hyundeok; Beck, Thomas

2011-04-01

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

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

Global transport of thermophilic bacteria in atmospheric dust.

Science.gov (United States)

Perfumo, Amedea; Marchant, Roger

2010-04-01

Aerosols from dust storms generated in the Sahara-Sahel desert area of Africa are transported north over Europe and periodically result in dry dust precipitation in the Mediterranean region. Samples of dust collected in Turkey and Greece following two distinct desert storm events contained viable thermophilic organisms of the genus Geobacillus, namely G. thermoglucosidasius and G. thermodenitrificans, and the recently reclassified Aeribacillus pallidus (formerly Geobacillus pallidus). We present here evidence that African dust storms create an atmospheric bridge between distant geographical regions and that they are also probably the source of thermophilic geobacilli later deposited over northern Europe by rainfall or dust plumes themselves. The same organisms (99% similarity in the 16S rDNA sequence) were found in dust collected in the Mediterranean region and inhabiting cool soils in Northern Ireland. This study also contributes new insights to the taxonomic identification of Geobacillus sp. Attempts to identify these organisms using 16S rRNA gene sequences have revealed that they contain multiple and diverse copies of the ribosomal RNA operon (up to 10 copies with nine different sequences), which dictates care in interpreting data about the systematics of this genus. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

Complete genome of the cellulolytic thermophile Acidothermus cellulolyticus 11B provides insights into its ecophysiological and evolutionary adaptations

Energy Technology Data Exchange (ETDEWEB)

Xie, Gary [Los Alamos National Laboratory; Detter, Chris [Los Alamos National Laboratory; Bruce, David [Los Alamos National Laboratory; Challacome, Jean F [Los Alamos National Laboratory; Brettin, Thomas S [Los Alamos National Laboratory; Barabote, Ravi D [UC DAVIS; Leu, David [UC DAVIS; Normand, Philippe [CNRS, UNIV LYON; Necsula, Anamaria [CNRS, UNIV LYON; Daubin, Vincent [CNRS, UNIV LYON; Medigue, Claudine [CNRS/GENOSCOPE; Adney, William S [NREL; Xu, Xin C [UC DAVIS; Lapidus, Alla [DOE JOINT GENOME INST.; Pujic, Pierre [CNRS, UNIV LYON; Richardson, Paul [DOE JOINT GENOME INST; Berry, Alison M [UC DAVIS

2008-01-01

We present here the complete 2.4 MB genome of the actinobacterial thermophile, Acidothermus cellulolyticus lIB, that surprisingly reveals thermophilic amino acid usage in only the cytosolic subproteome rather than its whole proteome. Thermophilic amino acid usage in the partial proteome implies a recent, ongoing evolution of the A. cellulolyticus genome since its divergence about 200-250 million years ago from its closest phylogenetic neighbor Frankia, a mesophilic plant symbiont. Differential amino acid usage in the predicted subproteomes of A. cellulolyticus likely reflects a stepwise evolutionary process of modern thermophiles in general. An unusual occurrence of higher G+C in the non-coding DNA than in the transcribed genome reinforces a late evolution from a higher G+C common ancestor. Comparative analyses of the A. cellulolyticus genome with those of Frankia and other closely-related actinobacteria revealed that A. cellulolyticus genes exhibit reciprocal purine preferences at the first and third codon positions, perhaps reflecting a subtle preference for the dinucleotide AG in its mRNAs, a possible adaptation to a thermophilic environment. Other interesting features in the genome of this cellulolytic, hot-springs dwelling prokaryote reveal streamlining for adaptation to its specialized ecological niche. These include a low occurrence of pseudogenes or mobile genetic elements, a flagellar gene complement previously unknown in this organism, and presence of laterally-acquired genomic islands of likely ecophysiological value. New glycoside hydrolases relevant for lignocellulosic biomass deconstruction were identified in the genome, indicating a diverse biomass-degrading enzyme repertoire several-fold greater than previously characterized, and significantly elevating the industrial value of this organism.

Complete genome of the cellulolytic thermophile Acidothermus cellulolyticus 11B provides insights into its ecophysiological and evolutionary adaptations

Energy Technology Data Exchange (ETDEWEB)

Xie, Gary [Los Alamos National Laboratory; Detter, John C [Los Alamos National Laboratory; Bruce, David C [Los Alamos National Laboratory; Challacombe, Jean F [Los Alamos National Laboratory; Brettin, Thomas S [Los Alamos National Laboratory; Necsulea, Anamaria [UNIV LYON; Daubin, Vincent [UNIV LYON; Medigue, Claudine [GENOSCOPE; Adney, William S [NREL; Xu, Xin C [UC DAVIS; Lapidus, Alla [JGI; Pujic, Pierre [UNIV LYON; Berry, Alison M [UC DAVIS; Barabote, Ravi D [UC DAVIS; Leu, David [UC DAVIS; Normand, Phillipe [UNIV LYON

2009-01-01

We present here the complete 2.4 MB genome of the actinobacterial thermophile, Acidothermus cellulolyticus 11B, that surprisingly reveals thermophilic amino acid usage in only the cytosolic subproteome rather than its whole proteome. Thermophilic amino acid usage in the partial proteome implies a recent, ongoing evolution of the A. cellulolyticus genome since its divergence about 200-250 million years ago from its closest phylogenetic neighbor Frankia, a mesophilic plant symbiont. Differential amino acid usage in the predicted subproteomes of A. cellulolyticus likely reflects a stepwise evolutionary process of modern thermophiles in general. An unusual occurrence of higher G+C in the non-coding DNA than in the transcribed genome reinforces a late evolution from a higher G+C common ancestor. Comparative analyses of the A. cellulolyticus genome with those of Frankia and other closely-related actinobacteria revealed that A. cellulolyticus genes exhibit reciprocal purine preferences at the first and third codon positions, perhaps reflecting a subtle preference for the dinucleotide AG in its mRNAs, a possible adaptation to a thermophilic environment. Other interesting features in the genome of this cellulolytic, hot-springs dwelling prokaryote reveal streamlining for adaptation to its specialized ecological niche. These include a low occurrence of pseudo genes or mobile genetic elements, a flagellar gene complement previously unknown in this organism, and presence of laterally-acquired genomic islands of likely ecophysiological value. New glycoside hydrolases relevant for lignocellulosic biomass deconstruction were identified in the genome, indicating a diverse biomass-degrading enzyme repertoire several-fold greater than previously characterized, and significantly elevating the industrial value of this organism.

Production of Sporotrichum thermophile xylanase by solid state fermentation utilizing deoiled Jatropha curcas seed cake and its application in xylooligosachharide synthesis.

Science.gov (United States)

Sadaf, Ayesha; Khare, S K

2014-02-01

De-oiled Jatropha curcas seed cake, a plentiful by-product of biodiesel industry was used as substrate for the production of a useful xylanase from Sporotrichum thermophile in solid state fermentation. Under the optimized conditions, 1025U xylanase/g (deoiled seed cake) was produced. The xylanase exhibited half life of 4h at 45°C and 71.44min at 50°C respectively. It was stable in a broad pH range of 7.0-11.0. Km and Vmax were 12.54mg/ml and 454.5U/ml/min respectively. S. thermophile xylanase is an endoxylanase free of exoxylanase activity, hence advantageous for xylan hydrolysis to produce xylooligosachharides. Hydrolysis of oat spelt xylan by S. thermophile xylanase yielded 73% xylotetraose, 15.4% xylotriose and 10% xylobiose. The S. thermophile endoxylanase thus seem potentially useful in the food industries. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

2018-03-01

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

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

Science.gov (United States)

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

2017-01-01

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

Proteome Profiling of Heat, Oxidative, and Salt Stress Responses in Thermococcus kodakarensis KOD1

Directory of Open Access Journals (Sweden)

Baolei eJia

2015-06-01

Full Text Available The thermophilic species, Thermococcus kodakarensis KOD1, a model microorganism for studying hyperthermophiles, has adapted to optimal growth under conditions of high temperature and salinity. However, the environmental conditions for the strain are not always stable, and this strain might face different stresses. In the present study, we compared the proteome response of T. kodakarensis to heat, oxidative, and salt stresses using two-dimensional electrophoresis, and protein spots were identified through MALDI-TOF/MS. Fifty-nine, forty-two, and twenty-nine spots were induced under heat, oxidative, and salt stresses, respectively. Among the up-regulated proteins, four proteins (a hypothetical protein, pyridoxal biosynthesis lyase, peroxiredoxin, and protein disulphide oxidoreductase were associated with all three stresses. Gene ontology analysis showed that these proteins were primarily involved metabolic and cellular processes. The KEGG pathway analysis suggested that the main metabolic pathways involving these enzymes were related to carbohydrate metabolism, secondary metabolite synthesis, and amino acid biosynthesis. These data might enhance our understanding of the functions and molecular mechanisms of thermophilic Archaea for survival and adaptation in extreme environments.

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.

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.

Molecular interactions within the halophilic, thermophilic, and mesophilic prokaryotic ribosomal complexes: clues to environmental adaptation.

Science.gov (United States)

Mallik, Saurav; Kundu, Sudip

2015-01-01

Using the available crystal structures of 50S ribosomal subunits from three prokaryotic species: Escherichia coli (mesophilic), Thermus thermophilus (thermophilic), and Haloarcula marismortui (halophilic), we have analyzed different structural features of ribosomal RNAs (rRNAs), proteins, and of their interfaces. We have correlated these structural features with the environmental adaptation strategies of the corresponding species. While dense intra-rRNA packing is observed in thermophilic, loose intra-rRNA packing is observed in halophilic (both compared to mesophilic). Interestingly, protein-rRNA interfaces of both the extremophiles are densely packed compared to that of the mesophilic. The intersubunit bridge regions are almost devoid of cavities, probably ensuring the proper formation of each bridge (by not allowing any loosely packed region nearby). During rRNA binding, the ribosomal proteins experience some structural transitions. Here, we have analyzed the intrinsically disordered and ordered regions of the ribosomal proteins, which are subjected to such transitions. The intrinsically disordered and disorder-to-order transition sites of the thermophilic and mesophilic ribosomal proteins are simultaneously (i) highly conserved and (ii) slowly evolving compared to rest of the protein structure. Although high conservation is observed at such sites of halophilic ribosomal proteins, but slow rate of evolution is absent. Such differences between thermophilic, mesophilic, and halophilic can be explained from their environmental adaptation strategy. Interestingly, a universal biophysical principle evident by a linear relationship between the free energy of interface formation, interface area, and structural changes of r-proteins during assembly is always maintained, irrespective of the environmental conditions.

Microorganisms involved in MIC

Energy Technology Data Exchange (ETDEWEB)

Sorensen, K. [Danish Technological Institute (Denmark)

2011-07-01

Microbiologically influenced corrosion (MIC) is a widespread problem that is difficult to detect and assess because of its complex mechanism. This paper presents the involvement of microorganisms in MIC. Some of the mechanisms that cause MIC include hydrogen consumption, production of acids, anode-cathode formation and electron shuttling. A classic bio-corrosive microorganism in the oil and gas industry is sulphate-reducing prokaryotes (SRP). Methanogens also increase corrosion rates in metals. Some of the phylogenetic orders detected while studying SRP and methanogens are archaeoglobales, clostridiales, methanosarcinales and methanothermococcus. There were some implications, such as growth of SRP not being correlated with growth of methanogens; methanogens were included in MIC risk assessment. A few examples are used to display how microorganisms are involved in topside corrosion and microbial community in producing wells. From the study, it can be concluded that, MIC risk assessment includes system data and empirical knowledge of the distribution and number of microorganisms in the system.

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

DEFF Research Database (Denmark)

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

1994-01-01

at up to 70 and 75 degrees C, with optima at 63 and 71 degrees C, respectively. Several sporulating thermophilic enrichments were morphologically similar to Desulfotomaculum spp. Dissimilatory sulfate reduction in the studied hydrothermal area of Lake Tanganyika apparently has an upper temperature limit...

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.

Isolation and Screening of Thermophilic Bacilli from Compost for Electrotransformation and Fermentation: Characterization of Bacillus smithii ET 138 as a New Biocatalyst

NARCIS (Netherlands)

Bosma, E.F.; Weijer, van de A.H.P.; Daas, M.J.A.; Oost, van der J.; Vos, de W.M.; Kranenburg, van R.

2015-01-01

Thermophilic bacteria are regarded as attractive production organisms for cost-efficient conversion of renewable resources to green chemicals, but their genetic accessibility is a major bottleneck in developing them into versatile platform organisms. In this study, we aimed to isolate thermophilic,

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

Recombinant thermoactive phosphoenolpyruvate carboxylase (PEPC) from Thermosynechococcus elongatus and its coupling with mesophilic/thermophilic bacterial carbonic anhydrases (CAs) for the conversion of CO2 to oxaloacetate.

Science.gov (United States)

Del Prete, Sonia; De Luca, Viviana; Capasso, Clemente; Supuran, Claudiu T; Carginale, Vincenzo

2016-01-15

With the continuous increase of atmospheric CO2 in the last decades, efficient methods for carbon capture, sequestration, and utilization are urgently required. The possibility of converting CO2 into useful chemicals could be a good strategy to both decreasing the CO2 concentration and for achieving an efficient exploitation of this cheap carbon source. Recently, several single- and multi-enzyme systems for the catalytic conversion of CO2 mainly to bicarbonate have been implemented. In order to design and construct a catalytic system for the conversion of CO2 to organic molecules, we implemented an in vitro multienzyme system using mesophilic and thermophilic enzymes. The system, in fact, was constituted by a recombinant phosphoenolpyruvate carboxylase (PEPC) from the thermophilic cyanobacterium Thermosynechococcus elongatus, in combination with mesophilic/thermophilic bacterial carbonic anhydrases (CAs), for converting CO2 into oxaloacetate, a compound of potential utility in industrial processes. The catalytic procedure is in two steps: the conversion of CO2 into bicarbonate by CA, followed by the carboxylation of phosphoenolpyruvate with bicarbonate, catalyzed by PEPC, with formation of oxaloacetate (OAA). All tested CAs, belonging to α-, β-, and γ-CA classes, were able to increase OAA production compared to procedures when only PEPC was used. Interestingly, the efficiency of the CAs tested in OAA production was in good agreement with the kinetic parameters for the CO2 hydration reaction of these enzymes. This PEPC also revealed to be thermoactive and thermostable, and when coupled with the extremely thermostable CA from Sulphurhydrogenibium azorense (SazCA) the production of OAA was achieved even if the two enzymes were exposed to temperatures up to 60 °C, suggesting a possible role of the two coupled enzymes in biotechnological processes. Copyright © 2015 Elsevier Ltd. All rights reserved.

An efficient Azorean thermophilic consortium for lignocellulosic biomass degradation

OpenAIRE

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

2015-01-01

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

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

Science.gov (United States)

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

2014-04-21

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

Electricity production and microbial characterization of thermophilic microbial fuel cells.

Science.gov (United States)

Dai, Kun; Wen, Jun-Li; Zhang, Fang; Ma, Xi-Wen; Cui, Xiang-Yu; Zhang, Qi; Zhao, Ting-Jia; Zeng, Raymond J

2017-11-01

Thermophilic microbial fuel cell (TMFC) offers many benefits, but the investigations on the diversity of exoelectrogenic bacteria are scarce. In this study, a two-chamber TMFC was constructed using ethanol as an electron donor, and the microbial dynamics were analyzed by high-throughput sequencing and 16S rRNA clone-library sequencing. The open-circuit potential of TMFC was approximately 650mV, while the maximum voltage was around 550mV. The maximum power density was 437mW/m 2 , and the columbic efficiency in this work was 20.5±6.0%. The Firmicutes bacteria, related to the uncultured bacterium clone A55_D21_H_B_C01 with a similarity of 99%, accounted for 90.9% of all bacteria in the TMFC biofilm. This unknown bacterium has the potential to become a new thermophilic exoelectrogenic bacterium that is yet to be cultured. The development of TMFC-involved biotechnologies will be beneficial for the production of valuable chemicals and generation of energy in the future. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bio-degradation of oily food waste employing thermophilic bacterial strains.

Science.gov (United States)

Awasthi, Mukesh Kumar; Selvam, Ammaiyappan; Chan, Man Ting; Wong, Jonathan W C

2018-01-01

The objective of this work was to isolate a novel thermophilic bacterial strain and develop a bacterial consortium (BC) for efficient degradation oily food waste. Four treatments were designed: 1:1 mixture of pre-consumption food wastes (PrCFWs) and post-consumption food wastes (PCFWs) (T-1), 1:2 mixture of PrCFWs and PCFWs mixture (T-2), PrCFWs (T-3) and PCFWs (T-4). Equal quantity of BC was inoculated into each treatment to compare the oil degradation efficiency. Results showed that after 15days of incubation, a maximum oil reduction of 65.12±0.08% was observed in treatment T-4, followed by T-2 (55.44±0.12%), T-3 (54.79±0.04%) and T-1 (52.52±0.02%), while oil reduction was negligible in control. Results indicate that the development of oil utilizing thermophilic BC was more cost-effective in solving the degradation of oily food wastes and conversion into a stable end product. Copyright © 2017 Elsevier Ltd. All rights reserved.

Radioresistant microorganisms and food irradiation

Energy Technology Data Exchange (ETDEWEB)

Ito, H [Japan Atomic Energy Research Inst., Takasaki, Gunma. Takasaki Radiation Chemistry Research Establishment

1976-01-01

This paper deals with Micrococcus radiodurans, Arthrobacter radiotolerance, etc., which were isolated and discovered as radioresistant microorganisms. As for the explanation of the mechanism of radioresistance of these microorganisms, the consideration that these organisms have marked repair power of the damaged DNA and have many opportunity to repair the damaged DNA because of their long fission term were cited. The relationship between the radioresistance of microorganisms and food irradiation was also mentioned.

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

Energy Technology Data Exchange (ETDEWEB)

Uchino, F

1982-01-01

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

Characterization of hemicellulase and cellulase from the extremely thermophilic bacterium Caldicellulosiruptor owensensis and their potential application for bioconversion of lignocellulosic biomass without pretreatment.

Science.gov (United States)

Peng, Xiaowei; Qiao, Weibo; Mi, Shuofu; Jia, Xiaojing; Su, Hong; Han, Yejun

2015-01-01

Pretreatment is currently the common approach for improving the efficiency of enzymatic hydrolysis on lignocellulose. However, the pretreatment process is expensive and will produce inhibitors such as furan derivatives and phenol derivatives. If the lignocellulosic biomass can efficiently be saccharified by enzymolysis without pretreatment, the bioconversion process would be simplified. The genus Caldicellulosiruptor, an obligatory anaerobic and extreme thermophile can produce a diverse set of glycoside hydrolases (GHs) for deconstruction of lignocellulosic biomass. It gives potential opportunities for improving the efficiency of converting native lignocellulosic biomass to fermentable sugars. Both of the extracellular (extra-) and intracellular (intra-) enzymes of C. owensensis cultivated on corncob xylan or xylose had cellulase (including endoglucanase, cellobiohydrolase and β-glucosidase) and hemicellulase (including xylanase, xylosidase, arabinofuranosidase and acetyl xylan esterase) activities. The enzymes of C. owensensis had high ability for degrading hemicellulose of native corn stover and corncob with the conversion rates of xylan 16.7 % and araban 60.0 %. Moreover, they had remarkable synergetic function with the commercial enzyme cocktail Cellic CTec2 (Novoyzmes). When the native corn stover and corncob were respectively, sequentially hydrolyzed by the extra-enzymes of C. owensensis and CTec2, the glucan conversion rates were 31.2 and 37.9 %,which were 1.7- and 1.9-fold of each control (hydrolyzed by CTec2 alone), whereas the glucan conversion rates of the steam-exploded corn stover and corncob hydrolyzed by CTec2 alone on the same loading rate were 38.2 and 39.6 %, respectively. These results show that hydrolysis by the extra-enzyme of C. owensensis made almost the same contribution as steam-exploded pretreatment on degradation of native lignocellulosic biomass. A new process for saccharification of lignocellulosic biomass by sequential hydrolysis

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

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McClendon Shara D

2012-07-01

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

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

Science.gov (United States)

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

2012-07-28

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

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

Champagne Pool (New Zealand) Thermophiles Yield Insights into the Evolution of Microbial Arsenic Resistance

Science.gov (United States)

Hug, K.; Krikowa, F.; Morgan, X.; Maher, W. A.; Stott, M. B.; Moreau, J. W.

2011-12-01

Arsenic is a highly toxic metalloid typically enriched in geothermal waters due to aqueous weathering of arsenic-bearing minerals. Investigation of enzymatic pathways by which thermophilic microorganisms cope with toxic arsenic levels may yield insights into the evolution of arsenic resistance mechanisms on the early Earth. At Wai-O-Tapu in the Taupo Volcanic Zone on the North Island of New Zealand, hot springs with temperatures of 30-90°C and elemental sulfur concentrations (expressed as equivalent sulfate) from 340 to 850 mg/l establish a range of environmental conditions. Total arsenic concentrations varied from 0.083 mg/l to 56 mg/l. Arsenic speciation analysis elucidated various biogeochemical arsenic transformations occurring within different springs. For example, in the Alum Cliff spring oxidizing conditions (Eh = 225 mV) were expected to stabilize dissolved arsenate (AsO43-). However, HPLC-ICPMS analyses yielded dissolved arsenate and arsenite (AsO33-) concentrations of 0.25 mg/l versus 43.3 mg/l, respectively, and point towards microbial arsenate reduction as the likely mechanism for arsenic redox transformation. 16S rRNA gene cloning of Alum Cliff DNA showed a predominantly archaeal population with the dominant clone "AC1_A1" most closely related (99% sequence similarity, NCBI BLAST°) to the uncultured Sulfolobus clone "ChP_97P" found in Champagne Pool (Childs et al., 2008). The closest isolated relative to AC1_A1 is Sulfolobus tokodaii str. TW with a sequence similarity of 94%. Arsenic speciation measurements from the Alum Cliff spring suggest that clone AC1_A1 features the arsenate reduction resistance mechanism, and we hypothesize therefore that an arsC (homolog or analog) provides this functionality. The organic arsenic species monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA), detected via HPLC-ICPMS at concentrations ranging from 1 μg/l to 12 μg/l in various springs, may also implicate microbial methyl-group transfers as an active

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....

40 CFR 725.85 - Microorganism identity.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Microorganism identity. 725.85 Section... to Information § 725.85 Microorganism identity. (a) Claims applicable to the period prior to... specific microorganism identity at the time of submission of the information. This claim will apply only to...

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

Structural comparison of tRNA m1A58 methyltransferases revealed different molecular strategies to maintain their oligomeric architecture under extreme conditions

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Guelorget Amandine

2011-12-01

Full Text Available Abstract Background tRNA m1A58 methyltransferases (TrmI catalyze the transfer of a methyl group from S-adenosyl-L-methionine to nitrogen 1 of adenine 58 in the T-loop of tRNAs from all three domains of life. The m1A58 modification has been shown to be essential for cell growth in yeast and for adaptation to high temperatures in thermophilic organisms. These enzymes were shown to be active as tetramers. The crystal structures of five TrmIs from hyperthermophilic archaea and thermophilic or mesophilic bacteria have previously been determined, the optimal growth temperature of these organisms ranging from 37°C to 100°C. All TrmIs are assembled as tetramers formed by dimers of tightly assembled dimers. Results In this study, we present a comparative structural analysis of these TrmIs, which highlights factors that allow them to function over a large range of temperature. The monomers of the five enzymes are structurally highly similar, but the inter-monomer contacts differ strongly. Our analysis shows that bacterial enzymes from thermophilic organisms display additional intermolecular ionic interactions across the dimer interfaces, whereas hyperthermophilic enzymes present additional hydrophobic contacts. Moreover, as an alternative to two bidentate ionic interactions that stabilize the tetrameric interface in all other TrmI proteins, the tetramer of the archaeal P. abyssi enzyme is strengthened by four intersubunit disulfide bridges. Conclusions The availability of crystal structures of TrmIs from mesophilic, thermophilic or hyperthermophilic organisms allows a detailed analysis of the architecture of this protein family. Our structural comparisons provide insight into the different molecular strategies used to achieve the tetrameric organization in order to maintain the enzyme activity under extreme conditions.

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

Science.gov (United States)

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

2005-08-01

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

Recombinant HAP Phytase of the Thermophilic Mold Sporotrichum thermophile: Expression of the Codon-Optimized Phytase Gene in Pichia pastoris and Applications.

Science.gov (United States)

Ranjan, Bibhuti; Satyanarayana, T

2016-02-01

The codon-optimized phytase gene of the thermophilic mold Sporotrichum thermophile (St-Phy) was expressed in Pichia pastoris. The recombinant P. pastoris harboring the phytase gene (rSt-Phy) yielded a high titer of extracellular phytase (480 ± 23 U/mL) on induction with methanol. The recombinant phytase production was ~40-fold higher than that of the native fungal strain. The purified recombinant phytase (rSt-Phy) has the molecular mass of 70 kDa on SDS-PAGE, with K m and V max (calcium phytate), k cat and k cat/K m values of 0.147 mM and 183 nmol/mg s, 1.3 × 10(3)/s and 8.84 × 10(6)/M s, respectively. Mg(2+) and Ba(2+) display a slight stimulatory effect, while other cations tested exert inhibitory action on phytase. The enzyme is inhibited by chaotropic agents (guanidinium hydrochloride, potassium iodide, and urea), Woodward's reagent K and 2,3-bunatedione, but resistant to both pepsin and trypsin. The rSt-Phy is useful in the dephytinization of broiler feeds efficiently in simulated gut conditions of chick leading to the liberation of soluble inorganic phosphate with concomitant mitigation in antinutrient effects of phytates. The addition of vanadate makes it a potential candidate for generating haloperoxidase, which has several applications.

Thermophilic and alkaliphilic Actinobacteria: biology and potential applications

Science.gov (United States)

Shivlata, L.; Satyanarayana, Tulasi

2015-01-01

Microbes belonging to the phylum Actinobacteria are prolific sources of antibiotics, clinically useful bioactive compounds and industrially important enzymes. The focus of the current review is on the diversity and potential applications of thermophilic and alkaliphilic actinobacteria, which are highly diverse in their taxonomy and morphology with a variety of adaptations for surviving and thriving in hostile environments. The specific metabolic pathways in these actinobacteria are activated for elaborating pharmaceutically, agriculturally, and biotechnologically relevant biomolecules/bioactive compounds, which find multifarious applications. PMID:26441937

Production of 2-deoxyribose 5-phosphate from fructose to demonstrate a potential of artificial bio-synthetic pathway using thermophilic enzymes.

Science.gov (United States)

Honda, Kohsuke; Maya, Shohei; Omasa, Takeshi; Hirota, Ryuichi; Kuroda, Akio; Ohtake, Hisao

2010-08-02

Six thermophilic enzymes from Thermus thermophilus were used to construct an 'artificial bio-synthetic pathway' for the production of 2-deoxyribose 5-phosphate from fructose. By a simple operation using six recombinant Escherichia coli strains producing the thermophilic enzymes, respectively, fructose was converted to 2-deoxyribose 5-phosphate with a molar yield of 55%. Copyright 2010 Elsevier B.V. All rights reserved.

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

Science.gov (United States)

de la Torre, J. R.

2010-12-01

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

Differences in lateral gene transfer in hypersaline versus thermal environments

Directory of Open Access Journals (Sweden)

House Christopher H

2011-07-01

Full Text Available Abstract Background The role of lateral gene transfer (LGT in the evolution of microorganisms is only beginning to be understood. While most LGT events occur between closely related individuals, inter-phylum and inter-domain LGT events are not uncommon. These distant transfer events offer potentially greater fitness advantages and it is for this reason that these "long distance" LGT events may have significantly impacted the evolution of microbes. One mechanism driving distant LGT events is microbial transformation. Theoretically, transformative events can occur between any two species provided that the DNA of one enters the habitat of the other. Two categories of microorganisms that are well-known for LGT are the thermophiles and halophiles. Results We identified potential inter-class LGT events into both a thermophilic class of Archaea (Thermoprotei and a halophilic class of Archaea (Halobacteria. We then categorized these LGT genes as originating in thermophiles and halophiles respectively. While more than 68% of transfer events into Thermoprotei taxa originated in other thermophiles, less than 11% of transfer events into Halobacteria taxa originated in other halophiles. Conclusions Our results suggest that there is a fundamental difference between LGT in thermophiles and halophiles. We theorize that the difference lies in the different natures of the environments. While DNA degrades rapidly in thermal environments due to temperature-driven denaturization, hypersaline environments are adept at preserving DNA. Furthermore, most hypersaline environments, as topographical minima, are natural collectors of cellular debris. Thus halophiles would in theory be exposed to a greater diversity and quantity of extracellular DNA than thermophiles.

Differences in lateral gene transfer in hypersaline versus thermal environments.

Science.gov (United States)

Rhodes, Matthew E; Spear, John R; Oren, Aharon; House, Christopher H

2011-07-08

The role of lateral gene transfer (LGT) in the evolution of microorganisms is only beginning to be understood. While most LGT events occur between closely related individuals, inter-phylum and inter-domain LGT events are not uncommon. These distant transfer events offer potentially greater fitness advantages and it is for this reason that these "long distance" LGT events may have significantly impacted the evolution of microbes. One mechanism driving distant LGT events is microbial transformation. Theoretically, transformative events can occur between any two species provided that the DNA of one enters the habitat of the other. Two categories of microorganisms that are well-known for LGT are the thermophiles and halophiles. We identified potential inter-class LGT events into both a thermophilic class of Archaea (Thermoprotei) and a halophilic class of Archaea (Halobacteria). We then categorized these LGT genes as originating in thermophiles and halophiles respectively. While more than 68% of transfer events into Thermoprotei taxa originated in other thermophiles, less than 11% of transfer events into Halobacteria taxa originated in other halophiles. Our results suggest that there is a fundamental difference between LGT in thermophiles and halophiles. We theorize that the difference lies in the different natures of the environments. While DNA degrades rapidly in thermal environments due to temperature-driven denaturization, hypersaline environments are adept at preserving DNA. Furthermore, most hypersaline environments, as topographical minima, are natural collectors of cellular debris. Thus halophiles would in theory be exposed to a greater diversity and quantity of extracellular DNA than thermophiles.

Thermophilic and alkaliphilic Actinobacteria: Biology and potential applications

Directory of Open Access Journals (Sweden)

L eShivlata

2015-09-01

Full Text Available Microbes belonging to the phylum Actinobacteria are prolific sources of antibiotics, clinically useful bioactive compounds and industrially important enzymes. The focus of the current review is on the diversity and potential applications of thermophilic and alkaliphilic actinobacteria, which are highly diverse in their taxonomy and morphology with a variety of adaptations for surviving and thriving in hostile environments. The specific metabolic pathways in these actinobacteria are activated for elaborating pharmaceutically, agriculturally and biotechnologically relevant biomolecules/bioactive compounds, which find multifarious applications.

Biofilms and planktonic cells of Deinococcus geothermalis in extreme environments

Science.gov (United States)

Panitz, Corinna; Reitz, Guenther; Rabbow, Elke; Rettberg, Petra; Flemming, Hans-Curt; Wingender, Jost; Froesler, Jan

In addition to the several extreme environments on Earth, Space can be considered as just another exceptional environment with a unique mixture of stress factors comprising UV radiation, vacuum, desiccation, temperature, ionizing radiation and microgravity. Life that processes in these environments can depend on the life forms and their state of living. The question is whether there are different strategies for individual microorganisms compared to communities of the same organisms to cope with the different factors of their surroundings. Comparative studies of the survi-val of these communities called biofilms and planktonic cell samples of Deinococcus geothermalis stand at the focal point of the presented investigations. A biofilm is a structured community of microorganisms that live encapsulated in a matrix of extracellular polymeric substances on a surface. Microorganisms living in a biofilm usually have significantly different properties to cooperate than individually living microorganisms of the same species. An advantage of the biofilm is increased resistance to various chemical and physical effects, while the dense extracellular matrix and the outer layer of the cells protect the interior of the microbial consortium. The space experiment BOSS (Biofilm organisms surfing Space) as part the ESA experimental unit EXPOSE R-2 with a planned launch date in July 2014 will be subsequently mounted on the Russian Svesda module outside the ISS. An international team of scientists coordinated by Dr. P. Rettberg will investigate the hypothesis whether microorganisms organized as biofilm outmatch the same microorganisms exposed individually in the long-term survival of the harsh environmental conditions as they occur in space and on Mars. Another protective function in the samples could be dust par-ticles for instance Mars regolith simulant contained inside the biofilms or mixed with the planktonic cells, as additional shelter especially against the extraterrestrial UV

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.

Microorganisms with a Taste for Vanilla: Microbial Ecology of Traditional Indonesian Vanilla Curing

Science.gov (United States)

Röling, Wilfred F. M.; Kerler, Josef; Braster, Martin; Apriyantono, Anton; Stam, Hein; van Verseveld, Henk W.

2001-01-01

The microbial ecology of traditional postharvesting processing of vanilla beans (curing) was examined using a polyphasic approach consisting of conventional cultivation, substrate utilization-based and molecular identification of isolates, and cultivation-independent community profiling by 16S ribosomal DNA based PCR-denaturing gradient gel electrophoresis. At two different locations, a batch of curing beans was monitored. In both batches a major shift in microbial communities occurred after short-term scalding of the beans in hot water. Fungi and yeast disappeared, although regrowth of fungi occurred in one batch during a period in which process conditions were temporarily not optimal. Conventional plating showed that microbial communities consisting of thermophilic and thermotolerant bacilli (mainly closely related to Bacillus subtilis, B. licheniformis,, and B. smithii) developed under the high temperatures (up to 65°C) that were maintained for over a week after scalding. Only small changes in the communities of culturable bacteria occurred after this period. Molecular analysis revealed that a proportion of the microbial communities could not be cultured on conventional agar medium, especially during the high-temperature period. Large differences between both batches were observed in the numbers of microorganisms, in species composition, and in the enzymatic abilities of isolated bacteria. These large differences indicate that the effects of microbial activities on the development of vanilla flavor could be different for each batch of cured vanilla beans. PMID:11319073

Identification of periodontopathogen microorganisms by PCR technique

Directory of Open Access Journals (Sweden)

Milićević Radovan

2008-01-01

Full Text Available INTRODUCTION Periodontitis is an inflammatory disease of the supporting tissues of teeth and is a major cause of tooth loss in adults. The onset and progression of periodontal disease is attributed to the presence of elevated levels of a consortium of pathogenic bacteria. Gram negative bacteria, mainly strict anaerobes, play the major role. OBJECTIVE The present study aimed to assess the presence of the main types of microorganisms involved in the aetiopathogenesis of periodontal disease: Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Eikenella corrodens, Treponema denticola, Tanerella forsythia and Prevotella intermedia in different samples collected from the oral cavity of 90 patients diagnosed with periodontitis. METHOD Bacterial DNA detection was performed in diverse biological materials, namely in dental plaque, gingival tissue and saliva, by means of multiplex PCR, a technique that allows simultaneous identification of two different bacterial genomes. RESULTS In the dental plaque of the periodontitis patients, Treponema denticola dominated. In the gingival tissue, Tannerella forsythia and Treponema denticola were the microbiota most frequently detected, whilst in saliva Treponema denticola and Eikenella corrodens were found with the highest percentage. CONCLUSION The identification of microorganisms by multiplex PCR is specific and sensitive. Rapid and precise assessment of different types of periodontopathogens is extremely important for early detection of the infection and consequently for the prevention and treatment of periodontal disease. In everyday clinical practice, for routine bacterial evaluation in patients with periodontal disease, the dental plaque is the most suitable biological material, because it is the richest in periodontal bacteria.

Using Thermal Inactivation Kinetics to Calculate the Probability of Extreme Spore Longevity: Implications for Paleomicrobiology and Lithopanspermia

Science.gov (United States)

Nicholson, Wayne L.

2003-12-01

Thermal inactivation kinetics with extrapolation were used to model the survival probabilities of spores of various Bacillus species over time periods of millions of years at the historical ambient temperatures (25-40 °) encountered within the 250 million-year-old Salado formation, from which the putative ancient spore-forming bacterium Salibacillus marismortui strain 2-9-3 was recovered. The model indicated extremely low-to-moderate survival probabilities for spores of mesophiles, but surprisingly high survival probabilities for thermophilic spores. The significance of the results are discussed in terms of the survival probabilities of (i) terrestrial spores in ancient geologic samples and (ii) spores transported between planets within impact ejecta.

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.

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

Science.gov (United States)

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

2005-08-01

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

Microbial community dynamics in thermophilic undefined milk starter cultures.

Science.gov (United States)

Parente, Eugenio; Guidone, Angela; Matera, Attilio; De Filippis, Francesca; Mauriello, Gianluigi; Ricciardi, Annamaria

2016-01-18

Model undefined thermophilic starter cultures were produced from raw milk of nine pasta-filata cheesemaking plants using a selective procedure based on pasteurization and incubation at high temperature with the objective of studying the microbial community dynamics and the variability in performances under repeated (7-13) reproduction cycles with backslopping. The traditional culture-dependent approach, based on random isolation and molecular characterization of isolates was coupled to the determination of pH and the evaluation of the ability to produce acid and fermentation metabolites. Moreover, a culture-independent approach based on amplicon-targeted next-generation sequencing was employed. The microbial diversity was evaluated by 16S rRNA gene sequencing (V1-V3 regions), while the microdiversity of Streptococcus thermophilus populations was explored by using novel approach based on sequencing of partial amplicons of the phosphoserine phosphatase gene (serB). In addition, the occurrence of bacteriophages was evaluated by qPCR and by multiplex PCR. Although it was relatively easy to select for a community dominated by thermophilic lactic acid bacteria (LAB) within a single reproduction cycle, final pH, LAB populations and acid production activity fluctuated over reproduction cycles. Both culture-dependent and -independent methods showed that the cultures were dominated by either S. thermophilus or Lactobacillus delbrueckii subsp. lactis or by both species. Nevertheless, subdominant mesophilic species, including lactococci and spoilage organisms, persisted at low levels. A limited number of serB sequence types (ST) were present in S. thermophilus populations. L. delbrueckii and Lactococcus lactis bacteriophages were below the detection limit of the method used and high titres of cos type S. thermophilus bacteriophages were detected in only two cases. In one case a high titre of bacteriophages was concurrent with a S. thermophilus biotype shift in the culture

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.

Nitrogen metabolism and kinetics of ammonia-oxidizing archaea.

Science.gov (United States)

Martens-Habbena, Willm; Stahl, David A

2011-01-01

The discovery of ammonia-oxidizing mesophilic and thermophilic Group I archaea changed the century-old paradigm that aerobic ammonia oxidation is solely mediated by two small clades of Beta- and Gammaproteobacteria. Group I archaea are extremely diverse and ubiquitous in marine and terrestrial environments, accounting for 20-30% of the microbial plankton in the global oceans. Recent studies indicated that many of these organisms carry putative ammonia monooxygenase genes and are more abundant than ammonia-oxidizing bacteria in most natural environments suggesting a potentially significant role in the nitrogen cycle. The isolation of Nitrosopumilus maritimus strain SCM1 provided the first direct evidence that Group I archaea indeed gain energy from ammonia oxidation. To characterize the physiology of this archaeal nitrifier, we developed a respirometry setup particularly suited for activity measurements in dilute microbial cultures with extremely low oxygen uptake rates. Here, we describe the setup and review the kinetic experiments conducted with N. maritimus and other nitrifying microorganisms. These experiments demonstrated that N. maritimus is adapted to grow on ammonia concentrations found in oligotrophic open ocean environments, far below the survival threshold of ammonia-oxidizing bacteria. The described setup and experimental procedures should facilitate physiological studies on other nitrifying archaea and oligotrophic microorganisms in general. Copyright © 2011 Elsevier Inc. All rights reserved.

Microorganism identification technique using radioactive and fluorescent agent

International Nuclear Information System (INIS)

Silman, R.E.

1983-01-01

A method for identifying microorganisms is claimed. An emissive agent is added to a specimen of microorganisms to produce a mix of emissive products. These products are detected and characteristic pattern functioning as an identifier for the microorganisms is derived. The identifier is then compared with identifiers representing known microorganisms

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...

Thermophilic fermentation of acetoin and 2,3-butanediol by a novel Geobacillus strain

Directory of Open Access Journals (Sweden)

Xiao Zijun

2012-12-01

Full Text Available Abstract Background Acetoin and 2,3-butanediol are two important biorefinery platform chemicals. They are currently fermented below 40°C using mesophilic strains, but the processes often suffer from bacterial contamination. Results This work reports the isolation and identification of a novel aerobic Geobacillus strain XT15 capable of producing both of these chemicals under elevated temperatures, thus reducing the risk of bacterial contamination. The optimum growth temperature was found to be between 45 and 55°C and the medium initial pH to be 8.0. In addition to glucose, galactose, mannitol, arabionose, and xylose were all acceptable substrates, enabling the potential use of cellulosic biomass as the feedstock. XT15 preferred organic nitrogen sources including corn steep liquor powder, a cheap by-product from corn wet-milling. At 55°C, 7.7 g/L of acetoin and 14.5 g/L of 2,3-butanediol could be obtained using corn steep liquor powder as a nitrogen source. Thirteen volatile products from the cultivation broth of XT15 were identified by gas chromatography–mass spectrometry. Acetoin, 2,3-butanediol, and their derivatives including a novel metabolite 2,3-dihydroxy-3-methylheptan-4-one, accounted for a total of about 96% of all the volatile products. In contrast, organic acids and other products were minor by-products. α-Acetolactate decarboxylase and acetoin:2,6-dichlorophenolindophenol oxidoreductase in XT15, the two key enzymes in acetoin metabolic pathway, were found to be both moderately thermophilic with the identical optimum temperature of 45°C. Conclusions Geobacillus sp. XT15 is the first naturally occurring thermophile excreting acetoin and/or 2,3-butanediol. This work has demonstrated the attractive prospect of developing it as an industrial strain in the thermophilic fermentation of acetoin and 2,3-butanediol with improved anti-contamination performance. The novel metabolites and enzymes identified in XT15 also indicated its

New thermophilic anaerobes that decompose crystalline cellulose

Energy Technology Data Exchange (ETDEWEB)

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

1985-01-01

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

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.

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

Science.gov (United States)

Thummes, Kathrin; Kämpfer, Peter; Jäckel, Udo

2007-07-01

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

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

Science.gov (United States)

Hecht, K; Wrba, A; Jaenicke, R

1989-07-15

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

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.

Sequential Detection of Thermophilic Lipase and Protease by Zymography.

Science.gov (United States)

Kurz, Liliana; Hernández, Zully; Contreras, Lellys M; Wilkesman, Jeff

2017-01-01

Lipase and protease present in cell-free fractions of thermophilic Bacillus sp. cultures were analyzed by polyacrylamide gel (PAG) electrophoresis. After run, the gel is electrotransferred to another PAG copolymerized with glycerol tributyrate, olive oil, and gelatin. This multi-substrate gel was incubated first for lipase detection, until bands appeared, and then stained with Coomassie for protease detection. Advantages of this sequential procedure are the detection of two different enzyme activities on a single PAG, beside time and resource saving.

Acquired Thermotolerance and Heat Shock Proteins in Thermophiles from the Three Phylogenetic Domains

DEFF Research Database (Denmark)

Trent, Jonathan D.; Gabrielsen, Mette; Jensen, Bo

1994-01-01

Thermophilic organisms from each of the three phylogenetic domains (Bacteria, Archaea, and Eucarya) acquired thermotolerance after heat shock. Bacillus caldolyticus grown at 60 degrees C and heat shocked at 69 degrees C for 10 min showed thermotolerance at 74 degrees C, Sulfolobus shibatae grown...

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

Directory of Open Access Journals (Sweden)

Begüm D. Topçuoğlu

2016-08-01

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

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

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

Science.gov (United States)

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

2015-02-01

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

Isolation of Thermophilic Lignin Degrading Bacteria from Oil-Palm Empty Fruit Bunch (EFB) Compost

Science.gov (United States)

Lai, C. M. T.; Chua, H. B.; Danquah, M. K.; Saptoro, A.

2017-06-01

Empty Fruit Bunch (EFB) is a potential and sustainable feedstock for bioethanol production due to its high cellulosic content and availability in Malaysia. Due to high lignin content of EFB and the lack of effective delignification process, commercial bioethanol production from EFB is presently not viable. Enzymatic delignification has been identified as one of the key steps in utilising EFB as a feedstock for bioethanol conversion. To date, limited work has been reported on the isolation of lignin degrading bacteria. Hence, there is a growing interest to search for new lignin degrading bacteria with greater tolerance to temperature and high level of ligninolytic enzymes for more effective lignin degradation. This study aimed to isolate and screen thermophilic ligninolytic microorganisms from EFB compost. Ten isolates were successfully isolated from EFB compost. Although they are not capable of decolorizing Methylene Blue (MB) dye under agar plate assay method, they are able to utilize lignin mimicked compound - guaiacol as a sole carbon on the agar plate assay. This infers that there is no correlation of ligninolytic enzymes with dye decolourization for all the isolates that have been isolated. However, they are able to produce ligninolytic enzymes (Lignin peroxidase, Manganese peroxidase, Laccase) in Minimal Salt Medium with Kraft Lignin (MSM-KL) with Lignin Peroxidase (LiP) as the predominant enzyme followed by Manganese Peroxidase (MnP) and Laccase (Lac). Among all the tested isolates, CLMT 29 has the highest LiP production up to 8.7673 U/mL following 24 h of growth.

16S rRNA-targeted probes for specific detection of Thermoanaerobacterium spp., Thermoanaerobacterium thermosaccharolyticum, and Caldicellulosiruptor spp. by fluorescent in situ hybridization in biohydrogen producing systems

DEFF Research Database (Denmark)

O-Thong, Sompong; Prasertsan, P.; Karakashev, Dimitar Borisov

2008-01-01

% and 36%), T. thermosaccharolyticum (16% and 10%), phylum Firmicutes (low G+C) gram positive bacteria (15% and 27%). Extreme-thermophilic (70 °C) hydrogen producing reactors, one fed with xylose and another, fed with lignocellulosic hydrolysate comprised of following major groups of hydrogen producers......: Caldicellulosiruptor spp. (40.5% and 20.5%), phylum Firmicutes (low G+C) gram positive bacteria (17% and 20%), Archaea (7% and 8.5%), and Thermoanaerobacterium spp. (0% and 5%). Results obtained, showed good applicability of the probes Tbm1282, Tbmthsacc184 and Ccs432 for specific detection and quantification...... of thermophilic and extreme-thermophilic hydrogen producers in complex environments....

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.

The Characterization of Psychrophilic Microorganisms and their potentially useful Cold-Active Glycosidases Final Progress Report

Energy Technology Data Exchange (ETDEWEB)

Brenchly, Jean E.

2008-06-30

Our studies of novel, cold-loving microorganisms have focused on two distinct extreme environments. The first is an ice core sample from a 120,000 year old Greenland glacier. The results of this study are particularly exciting and have been highlighted with press releases and additional coverage. The first press release in 2004 was based on our presentation at the General Meeting of the American Society for Microbiology and was augmented by coverage of our publication (Appl. Environ. Microbiol. 2005. Vol. 71:7806) in the Current Topics section of the ASM news journal, “Microbe.” Of special interest for this report was the isolation of numerous, phylogenetically distinct and potentially novel ultrasmall microorganisms. The detection and isolation of members of the ultrasmall population is significant because these cells pass through 0.2 micron pore filters that are generally used to trap microorganisms from environmental samples. Thus, analyses by other investigators that examined only cells captured on the filters would have missed a significant portion of this population. Only a few ultrasmall isolates had been obtained prior to our examination of the ice core samples. Our development of a filtration enrichment and subsequent cultivation of these organisms has added extensively to the collection of, and knowledge about, this important population in the microbial world.

Effects of seed sludge on fermentative characteristics and microbial community structures in thermophilic hydrogen fermentation of starch

Energy Technology Data Exchange (ETDEWEB)

Akutsu, Yohei; Tandukar, Madan; Kubota, Kengo; Harada, Hideki [Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Sendai, Miyagi 980-8579 (Japan); Li, Yu-You [Department of Civil and Environmental Engineering, Tohoku University, 6-6-06 Aoba, Sendai, Miyagi 980-8579 (Japan); Department of Urban and Environmental Engineering, Tianjin Institute of Urban Construction, Jinjinggonglu 26, Tianjin, 300384 (China)

2008-11-15

In this work, effects of seed sludge on thermophilic hydrogen fermentation were investigated. Five different kinds of sludge were separately inoculated in completely stirred tank reactors (CSTRs), without any pretreatment. The reactors were operated in parallel with starch as substrate under thermophilic condition (55 C) at a hydraulic retention time (HRT) of 24 h for 50 days. Stable hydrogen production was achieved in all reactors. The highest hydrogen yield (2.32 mol H{sub 2}/mol glucose) was obtained from the reactor seeded with thermophilically digested activated sludge. The stoichiometric equation of hydrogen fermentation calculated using the data obtained in this study was expressed as follows: starch ([C{sub 6}H{sub 10}O{sub 5}]n) {yields} 2.32n H{sub 2} + 2.14n CO{sub 2} + 0.50n acetate + 0.63n butyrate + 0.11n cell (C{sub 5}H{sub 7}NO{sub 2}). Microbial community structure was analyzed by polymerase chain reaction-denaturing gel gradient electrophoresis (PCR-DGGE) and 16S rRNA gene cloning. Close relatives of the Thermoanaerobacterium were found to be the most predominated one in all reactors. (author)

Seasonal variability of thermophilic Campylobacter spp. in raw milk sold by automatic vending machines in Lombardy Region

Directory of Open Access Journals (Sweden)

Barbara Bertasi

2016-06-01

Full Text Available In temperate climates, a seasonal trend was observed in the incidence of human campylobacteriosis cases, with peaks reported in spring and autumn in some countries, or in summer in others; a similar trend was observed in Campylobacter spp. dairy cattle faecal shedding, suggesting that cattle may play a role in the seasonal peak of human infection. The objectives of this study were to assess if a seasonal trend in thermophilic Campylobacter spp. contamination of raw milk exists and to evaluate a possible relation between this and the increase of human campylobacteriosis incidence in summer months. The results showed a mean prevalence of 1.6% of milk samples positive for thermophilic Campylobacter spp. with a wide range (0.0-3.1% in different months during the three years considered. The statistical analysis showed a significant difference (PCampylobacter spp. between warmer and cooler months (2.3 vs 0.6%. The evidence of a seasonal trend in thermophilic Campylobacter spp. contamination of raw milk sold for direct consumption, with an increase of the prevalence in warmer months, may represent one of the possible links between seasonal trend in cattle faecal shedding and seasonal trend in human campylobacteriosis.

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.

Extracellular electron transfer mechanisms between microorganisms and minerals

Energy Technology Data Exchange (ETDEWEB)

Shi, Liang; Dong, Hailiang; Reguera, Gemma; Beyenal, Haluk; Lu, Anhuai; Liu, Juan; Yu, Han-Qing; Fredrickson, James K.

2016-08-30

Electrons can be transferred from microorganisms to multivalent metal ions that are associated with minerals and vice versa. As the microbial cell envelope is neither physically permeable to minerals nor electrically conductive, microorganisms have evolved strategies to exchange electrons with extracellular minerals. In this Review, we discuss the molecular mechanisms that underlie the ability of microorganisms to exchange electrons, such as c-type cytochromes and microbial nanowires, with extracellular minerals and with microorganisms of the same or different species. Microorganisms that have extracellular electron transfer capability can be used for biotechnological applications, including bioremediation, biomining and the production of biofuels and nanomaterials.

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...

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

Liquid Water Restricts Habitability in Extreme Deserts

Science.gov (United States)

Cockell, Charles S.; Brown, Sarah; Landenmark, Hanna; Samuels, Toby; Siddall, Rebecca; Wadsworth, Jennifer

2017-04-01

Liquid water is a requirement for biochemistry, yet under some circumstances it is deleterious to life. Here, we show that liquid water reduces the upper temperature survival limit for two extremophilic photosynthetic microorganisms (Gloeocapsa and Chroococcidiopsis spp.) by greater than 40°C under hydrated conditions compared to desiccated conditions. Under hydrated conditions, thermal stress causes protein inactivation as shown by the fluorescein diacetate assay. The presence of water was also found to enhance the deleterious effects of freeze-thaw in Chroococcidiopsis sp. In the presence of water, short-wavelength UV radiation more effectively kills Gloeocapsa sp. colonies, which we hypothesize is caused by factors including the greater penetration of UV radiation into hydrated colonies compared to desiccated colonies. The data predict that deserts where maximum thermal stress or irradiation occurs in conjunction with the presence of liquid water may be less habitable to some organisms than more extreme arid deserts where organisms can dehydrate prior to being exposed to these extremes, thus minimizing thermal and radiation damage. Life in extreme deserts is poised between the deleterious effects of the presence and the lack of liquid water.

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

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Luis Concha-Marambio

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

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.

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

Science.gov (United States)

Willies, Simon; Isupov, Misha; Littlechild, Jennifer

2010-09-01

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

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.

Sexual crossing of thermophilic fungus Myceliophthora heterothallica improved enzymatic degradation of sugar beet pulp

NARCIS (Netherlands)

Aguilar-Pontes, Maria Victoria; Zhou, Miaomiao; van der Horst, Sjors; Theelen, Bart; de Vries, Ronald P.; van den Brink, Joost

2016-01-01

Background Enzymatic degradation of plant biomass requires a complex mixture of many different enzymes. Like most fungi, thermophilic Myceliophthora species therefore have a large set of enzymes targeting different linkages in plant polysaccharides. The majority of these enzymes have not been

Disentangling above- and below-ground facilitation drivers in arid environments: the role of soil microorganisms, soil properties and microhabitat.

Science.gov (United States)

Lozano, Yudi M; Armas, Cristina; Hortal, Sara; Casanoves, Fernando; Pugnaire, Francisco I

2017-12-01

Nurse plants promote establishment of other plant species by buffering climate extremes and improving soil properties. Soil biota plays an important role, but an analysis to disentangle the effects of soil microorganisms, soil properties and microclimate on facilitation is lacking. In three microhabitats (gaps, small and large Retama shrubs), we placed six microcosms with sterilized soil, two per soil origin (i.e. from each microhabitat). One in every pair received an alive, and the other a sterile, inoculum from its own soil. Seeds of annual plants were sown into the microcosms. Germination, survival and biomass were monitored. Soil bacterial communities were characterized by pyrosequencing. Germination in living Retama inoculum was nearly double that of germination in sterile inoculum. Germination was greater under Retama canopies than in gaps. Biomass was up to three times higher in nurse than in gap soils. Soil microorganisms, soil properties and microclimate showed a range of positive to negative effects on understory plants depending on species identity and life stage. Nurse soil microorganisms promoted germination, but the effect was smaller than the positive effects of soil properties and microclimate under nurses. Nurse below-ground environment (soil properties and microorganisms) promoted plant growth and survival more than nurse microhabitat. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

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

Energy Technology Data Exchange (ETDEWEB)

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

1986-01-01

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

Alicyclobacillus acidocaldarius Thermophilic Esterase EST2's Activity in Milk and Cheese Models

NARCIS (Netherlands)

Mandrich, L.; Manco, M.; Rossie, M.; Floris, E.; Jansen-van den Bosch, T.; Smit, G.; Wouters, J.A.

2006-01-01

The aim of this work was to investigate the behavior of thermophilic esterase EST2 from Alicyclobacillus acidocaldarius in milk and cheese models. The pure enzyme was used to compare the EST2 hydrolytic activity to the activity of endogenous esterase EstA from Lactococcus lactis. The results

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

Airborne microorganisms from waste containers.

Science.gov (United States)

Jedlicka, Sabrina S; Stravitz, David M; Lyman, Charles E

2012-01-01

In physician's offices and biomedical labs, biological waste is handled every day. This waste is disposed of in waste containers designed for holding red autoclave bags. The containers used in these environments are closed hands-free containers, often with a step pedal. While these containers protect the user from surface-borne microorganisms, the containers may allow airborne microorganisms to escape via the open/close mechanism because of the air current produced upon open/close cycles. In this study, the air current was shown to be sufficient to allow airborne escape of microorganisms held in the container, including Aspergillus niger. However, bacterial cultures, such as Escherichia coli and Lactococcus lactis did not escape. This may be due to the choice of bacterial cultures and the absence of solid waste, such as dust or other particulate matter in the waste containers, that such strains of bacteria could travel on during aerosolization. We compared these results to those obtained using a re-designed receptacle, which mimimizes air currents, and detected no escaping microorganisms. This study highlights one potential source of airborne contamination in labs, hospitals, and other environments that dispose of biological waste.

Sustainable biorefining in wastewater by engineered extreme alkaliphile Bacillus marmarensis.

Science.gov (United States)

Wernick, David G; Pontrelli, Sammy P; Pollock, Alexander W; Liao, James C

2016-02-01

Contamination susceptibility, water usage, and inability to utilize 5-carbon sugars and disaccharides are among the major obstacles in industrialization of sustainable biorefining. Extremophilic thermophiles and acidophiles are being researched to combat these problems, but organisms which answer all the above problems have yet to emerge. Here, we present engineering of the unexplored, extreme alkaliphile Bacillus marmarensis as a platform for new bioprocesses which meet all these challenges. With a newly developed transformation protocol and genetic tools, along with optimized RBSs and antisense RNA, we engineered B. marmarensis to produce ethanol at titers of 38 g/l and 65% yields from glucose in unsterilized media. Furthermore, ethanol titers and yields of 12 g/l and 50%, respectively, were produced from cellobiose and xylose in unsterilized seawater and algal-contaminated wastewater. As such, B. marmarensis presents a promising approach for the contamination-resistant biorefining of a wide range of carbohydrates in unsterilized, non-potable seawater.

Irradiation effect on bulgogi sauce for making commercial Korean traditional meat product, bulgogi[Bulgogi; Traditional meat products; Irradiation; Safety; Quality

Energy Technology Data Exchange (ETDEWEB)

Jo, C.; Kim, D.H.; Shin, M.G.; Kang, I.J.; Byun, M.W. E-mail: mwbyun@kaeri.re.kr

2003-12-01

Gamma-irradiated sauce of bulogogi, Korean traditional meat products, was compared with heat-pasteurized one to enhance its safety, quality, and commercial availability. The sauce is usually sold in refrigerated state with 2-7 days of self-life or heat-sterilized and sold in room temperature for a year. Raw vegetables, fruits and soy sauce for sauce making were highly contaminated by thermophillic microorganisms (totally 2.13x10{sup 6} CFU/g) and coliform bacteria (totally 5.90x10{sup 4} CFU/g) at the initial stage. Heat treatment (100 deg. C for 30 min) was effective to control coliform and microbes counted from Salmonella-Shigella selective agar in the sauce but not on thermophillic microorganisms, resulting in a rapid spoilage after 2 weeks at 20 deg. C. Gamma irradiation reduced the level of thermophillic microorganisms and the spoilage was prevented during storage for 4 weeks at 20 deg. C. Protease activity of the sauce was significantly reduced by heat treatment while was not changed by irradiation at 2.5, 5.0, and 10 kGy. Sensory evaluation showed that the irradiation was better in color than nonirradiated control or heat-treated sample. Results indicate that low dose irradiation (2.5-5.0 kGy) is effective to ensure safety of bulgogi sauce with acceptable sensory quality.

Irradiation effect on bulgogi sauce for making commercial Korean traditional meat product, bulgogi

International Nuclear Information System (INIS)

Jo, C.; Kim, D.H.; Shin, M.G.; Kang, I.J.; Byun, M.W.

2003-01-01

Gamma-irradiated sauce of bulogogi, Korean traditional meat products, was compared with heat-pasteurized one to enhance its safety, quality, and commercial availability. The sauce is usually sold in refrigerated state with 2-7 days of self-life or heat-sterilized and sold in room temperature for a year. Raw vegetables, fruits and soy sauce for sauce making were highly contaminated by thermophillic microorganisms (totally 2.13x10 6 CFU/g) and coliform bacteria (totally 5.90x10 4 CFU/g) at the initial stage. Heat treatment (100 deg. C for 30 min) was effective to control coliform and microbes counted from Salmonella-Shigella selective agar in the sauce but not on thermophillic microorganisms, resulting in a rapid spoilage after 2 weeks at 20 deg. C. Gamma irradiation reduced the level of thermophillic microorganisms and the spoilage was prevented during storage for 4 weeks at 20 deg. C. Protease activity of the sauce was significantly reduced by heat treatment while was not changed by irradiation at 2.5, 5.0, and 10 kGy. Sensory evaluation showed that the irradiation was better in color than nonirradiated control or heat-treated sample. Results indicate that low dose irradiation (2.5-5.0 kGy) is effective to ensure safety of bulgogi sauce with acceptable sensory quality

Efficient plant biomass degradation by thermophilic fungus Myceliophthora heterothallica.

Science.gov (United States)

van den Brink, Joost; van Muiswinkel, Gonny C J; Theelen, Bart; Hinz, Sandra W A; de Vries, Ronald P

2013-02-01

Rapid and efficient enzymatic degradation of plant biomass into fermentable sugars is a major challenge for the sustainable production of biochemicals and biofuels. Enzymes that are more thermostable (up to 70°C) use shorter reaction times for the complete saccharification of plant polysaccharides compared to hydrolytic enzymes of mesophilic fungi such as Trichoderma and Aspergillus species. The genus Myceliophthora contains four thermophilic fungi producing industrially relevant thermostable enzymes. Within this genus, isolates belonging to M. heterothallica were recently separated from the well-described species M. thermophila. We evaluate here the potential of M. heterothallica isolates to produce efficient enzyme mixtures for biomass degradation. Compared to the other thermophilic Myceliophthora species, isolates belonging to M. heterothallica and M. thermophila grew faster on pretreated spruce, wheat straw, and giant reed. According to their protein profiles and in vitro assays after growth on wheat straw, (hemi-)cellulolytic activities differed strongly between M. thermophila and M. heterothallica isolates. Compared to M. thermophila, M. heterothallica isolates were better in releasing sugars from mildly pretreated wheat straw (with 5% HCl) with a high content of xylan. The high levels of residual xylobiose revealed that enzyme mixtures of Myceliophthora species lack sufficient β-xylosidase activity. Sexual crossing of two M. heterothallica showed that progenies had a large genetic and physiological diversity. In the future, this will allow further improvement of the plant biomass-degrading enzyme mixtures of M. heterothallica.

Mercury resistance and mercuric reductase activities and expression among chemotrophic thermophilic Aquificae.

Science.gov (United States)

Freedman, Zachary; Zhu, Chengsheng; Barkay, Tamar

2012-09-01

Mercury (Hg) resistance (mer) by the reduction of mercuric to elemental Hg is broadly distributed among the Bacteria and Archaea and plays an important role in Hg detoxification and biogeochemical cycling. MerA is the protein subunit of the homodimeric mercuric reductase (MR) enzyme, the central function of the mer system. MerA sequences in the phylum Aquificae form the deepest-branching lineage in Bayesian phylogenetic reconstructions of all known MerA homologs. We therefore hypothesized that the merA homologs in two thermophilic Aquificae, Hydrogenobaculum sp. strain Y04AAS1 (AAS1) and Hydrogenivirga sp. strain 128-5-R1-1 (R1-1), specified Hg resistance. Results supported this hypothesis, because strains AAS1 and R1-1 (i) were resistant to >10 μM Hg(II), (ii) transformed Hg(II) to Hg(0) during cellular growth, and (iii) possessed Hg-dependent NAD(P)H oxidation activities in crude cell extracts that were optimal at temperatures corresponding with the strains' optimal growth temperatures, 55°C for AAS1 and 70°C for R1-1. While these characteristics all conformed with the mer system paradigm, expression of the Aquificae mer operons was not induced by exposure to Hg(II) as indicated by unity ratios of merA transcripts, normalized to gyrA transcripts for hydrogen-grown AAS1 cultures, and by similar MR specific activities in thiosulfate-grown cultures with and without Hg(II). The Hg(II)-independent expression of mer in the deepest-branching lineage of MerA from bacteria whose natural habitats are Hg-rich geothermal environments suggests that regulated expression of mer was a later innovation likely in environments where microorganisms were intermittently exposed to toxic concentrations of Hg.

Production and partial characterisation of feruloyl esterase by Sporotrichum thermophile in solid-state fermentation

DEFF Research Database (Denmark)

Topakas, E.; Kalogeris, E.; Kekos, D.

2003-01-01

A number of factors affecting production of feruloyl esterase an enzyme that hydrolyse ester linkages of ferulic acid (FA) in plant cell walls, by the thermophylic fungus Sporotrichum thermophile under solid state fermentation (SSF) were investigated. Initial moisture content and type of carbon...

Doppler speedometer for micro-organisms

International Nuclear Information System (INIS)

Penkov, F.; Tuleushev, A.; Lisitsyn, V.; Kim, S.; Tuleushev, Yu.

1996-01-01

Objective of Investigations: Development and creation of the Doppler speedometer for micro-organisms which allows to evaluate, in a real temporal scale, variations in the state of water suspension of micro-organisms under the effect of chemical, physical and other external actions. Statement of the Problem The main problem is absence of reliable, accessible for users and simple, in view of application, Doppler speedometers for micro-organisms. Nevertheless, correlation Doppler spectrometry in the regime of heterodyning the supporting and cell-scattered laser radiation is welt known. The main idea is that the correlation function of photo-current pulses bears an information on the averages over the assembly of cell velocities. For solving the biological problems, construction of auto-correlation function in the real-time regime with the delay time values comprising, function in the real-time regime with the delay time values comprising, nearly, 100 me (10 khz) or higher is needed. Computers of high class manage this problem using but the program software. Due to this, one can simplify applications of the proposed techniques provided he creates the Doppler speedometer for micro-organism on a base of the P entium . Expected Result Manufactured operable mock-up of the Doppler speedometer for micro-organisms in a form of the auxiliary computer block which allows to receive an information, in the real time scale, on the results of external effects of various nature on the cell assembly in transparent medium with a small volume of the studied cell suspension

Inactivation of Microorganisms

Science.gov (United States)

Alzamora, Stella Maris; Guerrero, Sandra N.; Schenk, Marcela; Raffellini, Silvia; López-Malo, Aurelio

Minimal processing techniques for food preservation allow better retention of product flavor, texture, color, and nutrient content than comparable conventional treatments. A wide range of novel alternative physical factors have been intensely investigated in the last two decades. These physical factors can cause inactivation of microorganisms at ambient or sublethal temperatures (e.g., high hydrostatic pressure, pulsed electric fields, ultrasound, pulsed light, and ultraviolet light). These technologies have been reported to reduce microorganism population in foods while avoiding the deleterious effects of severe heating on quality. Among technologies, high-energy ultrasound (i.e., intensities higher than 1 W/cm2, frequencies between 18 and 100 kHz) has attracted considerable interest for food preservation applications (Mason et al., 1996; Povey and Mason, 1998).

The first collection of spacecraft-associated microorganisms: a public source for extremotolerant microorganisms from spacecraft assembly clean rooms.

Science.gov (United States)

Moissl-Eichinger, Christine; Rettberg, Petra; Pukall, Rüdiger

2012-11-01

For several reasons, spacecraft are constructed in so-called clean rooms. Particles could affect the function of spacecraft instruments, and for missions under planetary protection limitations, the biological contamination has to be restricted as much as possible. The proper maintenance of clean rooms includes, for instance, constant control of humidity and temperature, air filtering, and cleaning (disinfection) of the surfaces. The combination of these conditions creates an artificial, extreme biotope for microbial survival specialists: spore formers, autotrophs, multi-resistant, facultative, or even strictly anaerobic microorganisms have been detected in clean room habitats. Based on a diversity study of European and South-American spacecraft assembly clean rooms, the European Space Agency (ESA) has initialized and funded the creation of a public library of microbial isolates. Isolates from three different European clean rooms, as well as from the final assembly and launch facility in Kourou (French Guiana), have been phylogenetically analyzed and were lyophilized for long-term storage at the German Culture Collection facilities in Brunswick, Germany (Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen). The isolates were obtained by either following the standard protocol for the determination of bioburden on, and around, spacecraft or the use of alternative cultivation strategies. Currently, the database contains 298 bacterial strains. Fifty-nine strains are Gram-negative microorganisms, belonging to the α-, β- and γ-Proteobacteria. Representatives of the Gram-positive phyla Actinobacteria, Bacteroidetes/Chlorobi, and Firmicutes were subjected to the collection. Ninety-four isolates (21 different species) of the genus Bacillus were included in the ESA collection. This public collection of extremotolerant microbes, which are adapted to a complicated artificial biotope, provides a wonderful source for industry and research focused on

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...

Biofouling of marbles by oxygenic photosynthetic microorganisms.

Science.gov (United States)

Karaca, Zeki; Öztürk, Ayten; Çolak, Emel

2015-08-01

Phototrophic microorganisms disfigure the surfaces of different types of stone. Stone structure is damaged by the activity of photoautotrophic and other microorganisms. However, to date few, investigations have been undertaken into the relationship between microorganisms and the properties of different types of marble. In this study, biological activity of photoautotrophic microorganisms on three types of marble (Yatagan White, Giallo Anticato and Afyon White) was investigated under laboratory conditions over a short period of time. The three types of marble supported the growth of phototrophic microbial communities on their outer and inner layers, turning their original colour from white to a yellowish green colour. The porosity of the marble types facilitated filamentous microbial growth in the presence of water. Scanning electron microscope analysis revealed the accumulation of aggregates such as small spherical, fibrillar, calcified globular bodies on the inner surfaces of the marbles. This suggests that the microscopic characteristics of particular marble types may stimulate the growth of certain types of microorganisms.