When grown on formate, formate-CO, and methanol-CO, Butyribacterium methylotrophicum contained high levels of tetrahydrofolate (H4folate) and required enzymes, carbon monoxide dehydrogenase, formate dehydrogenase, and hydrogenase. The activities of methylene-H4folate reductase were comparable to other H4 folate activities (which ranged from 0.55 to 9.28 ...

When grown on formate, formate-CO, and methanol-CO, Butyribacterium methylotrophicum contained high levels of tetrahydrofolate (H4folate) and required enzymes, carbon monoxide dehydrogenase, formate dehydrogenase, and hydrogenase. The activities of methylene-H4folate reductase were comparable to other H4 folate activities (which ranged from 0.55 to 9.28 ...

The catabolism of methanol, formate, or carbon monoxide to acetate or butyrate or both was examined in two acetogenic bacteria. Butyribacterium methylotrophicum simultaneously transformed methanol and formate mainly to butyrate with concomitant H2 and CO2 production and consumption. In contrast, methanol plus CO was primarily converted ...

Objectives of this project dealt with understanding one- and multicarbon metabolism in acetogenic and methanogenic bacteria. The biochemistry of acetate catabolism in Methanosarcina barkeri in relation to their major enzyme activities, co-factors and intermediates were studied. The physiological function of CO-dehydrogenase was investigated and found to be involved in hydrogen ...

Butyribacterium methylotrophicum is an anaerobic bacterium that can convert methanol to butyrate. This ability to produce longer- chain carbon compounds from C1 substrates could be of commercial significance. The fermentation rates and product formation depend on the methanol/bicarbonate ratios during fermentation. The kinetics of batch fermentation fit ...

Butyribacterium methylotrophicum is an anaerobic bacterium that can convert methanol to butyrate. This ability to produce longer-chain carbon compounds from C/sub 1/ substrates could be of commercial significance. The fermentation rates and product formation depend on the methanol/bicarbonate ratios during fermentation. The kinetics of batch fermentation ...

Butyribacterium methylotrophicum has been grown on carbon monoxide as its carbon and energy source in the presence of various surfactants that are capable of forming microbubble dispersions for the screening of surfactants for use in microbubble-sparged synthesis gas fermentations. In the range of 0-3 times the critical micelle concentration, the presence ...

The project deals with understanding the fundamental biochemical mechanisms that physiologically control and regulate carbon and electron flow in anaerobic chemosynthetic bacteria that couple metabolism of single carbon compounds and hydrogen to the production of organic acids (formic, acetic, butyric, and succinic) or methane. The authors compare the regulation of carbon dioxide and hydrogen ...

The proposed research project consists of an integrated, two-stage fermentation and a highly energy-efficient product separation scheme. In the first fermentation, Butyribacterium methylotrophicum converts carbon monoxide (CO) into butyric acid and acetic...

The overall objective of the project is to develop an integrated two-stage fermentation process for conversion of coal-derived synthesis gas to a mixture of alcohols. This is achieved in two steps. In the first steps, Butyribacterium methylotrophicum converts carbon monoxide (CO) to butyric and acetic acids. Subsequent fermentation of the acids by ...

The overall objective of the project is to develop an integrated two-stage fermentation process for conversion of coal-derived synthesis gas to a mixture of alcohols. This is achieved in two steps. In the first step, Butyribacterium methylotrophicum conve...

The overall objective of the project is to develop an integrated two stage fermentation process for conversion of coal-derived synthesis gas to a mixture of alcohols. This is achieved in two steps. In the first step, Butyribacterium methylotrophicum conve...

Anaerobic bioconversion of methanol and CO by Butyribacterium methylotrophicum is discussed. B. methylotrophicum can ferment methanol heterotrophically, and a metabolic mutant (CO strain) can ferment CO autotrophically, producing acetic and butyric acids as reduced metabolic end products. Batch fermentation data show that product ...

A ferredoxin and a rubredoxin from Butyribacterium methylotrophicum, which displays a carbonyl-dependent acetyl-coenzyme A synthesis, were purified to electrophoretic homogeneity. The two electron carriers showed absorption spectra similar to those in Clostridium species. The ferredoxin displayed absorption peaks at 280 and 391 nm, while rubredoxin ...

The use of coal-derived synthesis gas as an industrial feedstock for production of fuels and chemicals has become an increasingly attractive alternative to present petroleum-based chemicals production. However, one of the major limitations in developing such a process is the required removal of catalyst poisons such as hydrogen sulfide (H{sub 2}S), carbonyl sulfide (COS), and other trace ...

This project on indirect liquefaction of coal derived synthesis gas will focus on two stage anaerobic bioconversion. The first stage will address bioconversion of synthesis gas (CO, H/sub 2//CO/sub 2/) to volatile fatty acids by a CO adapted strain of Butyribacterium methylotrophicum. The second stage will address bioconversion of fatty acids to ...

The overall objective of the project is to develop an integrated two stage fermentation process for conversion of coal-derived synthesis gas to a mixture of alcohols. This is achieved in two steps. In the first step, Butyribacterium methylotrophicum converts carbon monoxide (CO) to butyric and acetic acids. Subsequent fermentation of the acids by ...

The major goal of the project is to understand the basic physiology and biochemistry of one carbon metabolism in anaerobic bacteria that produce organic acids or methane. The aim is to identify key rate, yield and regulatory features of their metabolism and to relate this knowledge to the improvement or development of technology for the bioconversion of organic pyrolysis products (i.e., H/sub 2/, ...

The purpose of this project is to develop a biological process for the production of liquid fuels from coal-derived synthesis gas feedstocks. A two-stage, anaerobic bioconversion process is proposed, where in the first stage the carbon monoxide (CO) gas is converted to butyric and acetic acids by the CO strain of Butyribacterium methylotrophicum. In the ...

The Marburg strain of Butyribacterium methylotrophicum did not grow on CO alone but did consume CO during growth on a variety of substrates in the presence of a 100% CO gas phase. We selected a strain (the CO strain) that grew vigorously on CO alone. The ability of the CO strain to grow on CO was stable through multiple transfers in the absence of CO. CO ...

The proposed research project consists of an integrated, two-stage fermentation and a highly energy-efficient product separation scheme. In the first fermentation, Butyribacterium methylotrophicum converts carbon monoxide (CO) into butyric acid and acetic acids which are then converted into butanol, ethanol, and a small amount of acetone in the second ...

The use of coal-derived synthesis gas as an industrial feedstock for production of fuels and chemicals has become an increasingly attractive alternative to present petroleum-based chemicals production. However, one of the major limitations in developing such a process is the required removal of catalyst poisons such as hydrogen sulfide (H{sub 2}S), carbonyl sulfide (COS), and other trace ...

Synthesis-gas fermentations have typically been gas-to-liquid mass-transfer-limited due to low solubilities of the gaseous substrates. A potential method to enhance mass-transfer rates is to sparge with microbubble dispersions. Mass-transfer coefficients for microbubble dispersions were measured in a bubble column. Oxygen microbubbles were formed in a dilute Tween 20 solution using a spinning disk ...

The project on biotechnology of indirect liquefaction was focused on conversion of coal derived synthesis gas to liquid fuels using a two-stage, acidogenic and solventogenic, anaerobic bioconversion process. The acidogenic fermentation used a novel and versatile organism, Butyribacterium methylotrophicum, which was fully capable of using CO as the sole ...

The project on biotechnology of indirect liquefaction was focused on conversion of coal derived synthesis gas to liquid fuels using a two-stage, acidogenic and solventogenic, anaerobic bioconversion process. The acidogenic fermentation used a novel and versatile organism, Butyribacterium methylotrophicum, which was fully capable of using CO as the sole ...

The overall objective of the project is to develop an integrated two-stage fermentation process for conversion of coal-derived synthesis gas to a mixture of alcohols. This is achieved in two steps. In the first step, Butyribacterium methylotrophicum converts carbon monoxide (CO) to butyric and acetic acids. Subsequent fermentation of the acids by ...

The overall objective of the project is to develop an integrated two-stage fermentation process for conversion of coal-derived synthesis gas to a mixture of alcohols. This is achieved in two steps. In the first step, Butyribacterium methylotrophicum converts carbon monoxide (CO) to butyric and acetic acids. Subsequent fermentation of the acids by ...

A novel extremely haloalkaliphilic, strictly anaerobic, acetogenic bacterium strain APO was isolated

The effects of a live strain of Saccharomyces cerevisiae on hydrogen utilization and acetate and methane production by two hydrogenotrophic ruminal microorganisms, an acetogenic bacterial strain and an archaea methanogen, were investigated. The addition of yeast cells enhanced by more than fivefold the hydrogenotrophic metabolism of the acetogenic strain ...

... filamentous, acetogenic and sulfate reducing bacteria in biofilm formation and ... and actual corrosion status of the pipes (personal communication ...

A thermophilic, fermentative microaerophile (ET-5b) and a thermophilic acetogen (ET-5a) were coisolated from oxic soil obtained from Egypt. The 16S rRNA gene sequence of ET-5a was 99.8% identical to that of the classic acetogen Moorella thermoacetica. Further analyses confirmed t...

The major volatile acid produced by Haemophilus vaginalis was acetic acid. The absence of propionate, butyrate, and cellular branched-chain fatty acids indicates that H. vaginalis is not related to Propionibacterium or Butyribacterium.

The acetogens, although phylogenetically diverse, can be characterized by their possession of the acetyl coenzyme A (acetyl-CoA) pathway for autotrophic CO{sub 2} fixation. The gene encoding formyltetrahydrofolate synthetase, a key enzyme of the acetyl-CoA pathway, was previously cloned from the thermophilic acetogen Clostridium thermoaceticum and has now ...

The present work reports on autotrophic metabolism in four H2/CO2-utilizing acetogenic bacteria isolated from the human colon (two Clostridium species, one Streptococcus species, and Ruminococcus hydrogenotrophicus). H2/CO2-utilization by these human acetogenic strains occurred during both exponential and stationary phases of growth. Acetate was the major ...

The aim of this work was to determine the effect of yeast extract and of its vitamin contents on autotrophic and heterotrophic growth and metabolism of four acetogenic bacteria from the human colon. Yeast extract exerted a stimulatory effect on autotrophic growth of the colonic acetogens, but concentration of this compound above 1-2 g. L-1 in the medium ...

Isolate KH was obtained from forest soil and found to be composed of two functionally linked anaerobes, KHa and KHb. Gene analyses (16S rRNA, fhs, cooS) identified KHa as an acetogenic strain of Clostridium glycolicum and KHb as Bacteroides xylanolyticus. KHb fermented xylan and other saccharides that KHa could not utilize and formed products (e.g., ethanol and H(2)) that ...

Acetogens utilize the acetyl-CoA Wood-Ljungdahl pathway as a terminal electron-accepting, energy-conserving, CO(2)-fixing process. The decades of research to resolve the enzymology of this pathway (1) preceded studies demonstrating that acetogens not only harbor a novel CO(2)-fixing pathway, but are also ecologically important, and (2) overshadowed the ...

... Allows users to query the DoD laboratory community or other ... our hypothesis that fermentative acetogenic, and sulfate-reducing bacteria residing in ...

Seagrasses are rooted in anoxic, sulfate-reducing sediments. However, the seagrass root is oxygenated during the daytime, becoming anoxic at night. Root thin sections hydridized with 33P-labeled probes revealed the presence of acetogenic and sulfate-reducing bacteria in the rhizo...

Seagrasses are rooted in anoxic, sulfate-reducing sediments. However, the seagrass root is oxygenated during the daytime, becoming anoxic at night. Root thin sections hydridized with 33P-labeled probes revealed the presence of acetogenic and sulfate-reducing bacteria in the rhizo...

Eubacterium limosum KIST612 is an anaerobic acetogenic bacterium that uses CO as the sole carbon/energy source and produces acetate, butyrate, and ethanol. To evaluate its potential as a syngas microbial catalyst, we have sequenced the complete 4.3-Mb genome of E. limosum KIST612. PMID:21036996

Eubacterium limosum KIST612 is an anaerobic acetogenic bacterium that uses CO as the sole carbon/energy source and produces acetate, butyrate, and ethanol. To evaluate its potential as a syngas microbial catalyst, we have sequenced the complete 4.3-Mb genome of E. limosum KIST612.

Skatole (3-methyl-indole) is a malodorous chemical in stored swine manure and is implicated as a component of foul tasting pork. Definitive evidence for the skatole pathway is lacking. Deuterium-labeled substrates were employed to resolve this pathway in the acetogenic bacterium Clostridium drakei...

This reporting period, progress is reported on the following: metabolic pathway of solvent production in B. methylotrophicum; the biochemical mechanism for metabolic regulation of the succinate fermentation; models to understand the physiobiochemical function of formate metabolism in anaerobes and; models for understanding the influence of low pH on one carbon metabolism. ...

This reporting period, progress is reported on the following: metabolic pathway of solvent production in B. methylotrophicum; the biochemical mechanism for metabolic regulation of the succinate fermentation; models to understand the physiobiochemical function of formate metabolism in anaerobes and; models for understanding the influence of low pH on one carbon metabolism. ...

The overall objective of the project is to develop two stage fermentation process for conversion of coal-derived synthesis gas to a mixture of alcohols. This is achieved in two steps. In the first step, B .methylotrophicum converts carbon monoxide (CO) to...

Acetogens were enumerated from root homogenates of the black needlerush Juncus roemerianus obtained from a nearly pristine salt marsh. An isolated colony, ST1, yielded acetogenic activity and was initially thought to be a pure culture; however, ST1 was subsequently found to be composed of an aerotolerant fermentative anaerobe (RC) and an ...

The objective of the current study was to expand the knowledge of the role of acetogenic Bacteria in high rate anaerobic digesters. To this end, acetogens were enriched by supplying a variety of acetogenic growth supportive substrates to two laboratory scale high rate upflow anaerobic sludge bed (UASB) reactors operated at 37 degrees C ...

Methanogenic and acetogenic bacteria metabolize carbon monoxide, methanol, formate, hydrogen and carbon dioxide gases and, in the case of certain methanogens, acetate, by single-carbon (C/sub 1/) biochemical mechanisms. Many of these reactions occur while the C1 compounds are linked to pteridine derivatives and tetrapyrrole coenzymes, including corrinoids, which are used to ...

Clostridium ljungdahlii sp. nov. strain ATCC 49587T (T = type strain) was isolated from chicken yard waste for its ability to produce ethanol from synthesis gas. This gram-positive, motile, sporeforming rod's metabolism was primarily acetogenic. C. ljungdahlii grew with carbon monoxide, hydrogen and carbon dioxide, ethanol, pyruvate, arabinose, xylose, fructose, or glucose. ...

Our project focussed on understanding of one and multicarbon metabolism in acetogenic and methanogenic bacteria. The studies with acetate catabolism pathway in Methanosarcina barkeri showed involvement of methyl reductase, methyl coenzyme M and carbon mon...

The anerobic degradation of organic matter to methane is a complex interaction of basically three groups of bacteria (fermentative, acetogenic, methano-genic). This report provides a description of the different types of anerobic treatment that have been developed. The processes ...

The contribution of seagrasses to the stability and fertility of estuarine ecosystems is well established. Loss of seagrasses in recent years to disease and coastal development underscores the importance of understanding the microbial ecology of seagrasses, and the possible roles...

Microbial electrosynthesis, a process in which microorganisms use electrons derived from electrodes to reduce carbon dioxide to multicarbon, extracellular organic compounds, is a potential strategy for capturing electrical energy in carbon-carbon bonds of readily stored and easily distributed products, such as transportation fuels. To date, only one organism, the acetogen ...

Skatole is a potent odorant produced by anaerobic degradation of stored animal waste materials. Little is known of the phylogeny of skatole-producing microorganisms or the conditions that favor their growth. These deficiencies hamper attempts to reduce skatole production. Previous studies suggest ...

Seagrasses are adapted to being rooted in reduced, anoxic sediments with high rates of sulfate reduction. During the day, an oxygen gradient is generated around the roots, becoming anoxic at night. Thus, obligate anaerobic bacteria in the rhizosphere have to tolerate elevated oxy...

Sixty-two partial formyltetrahydrofolate synthetase (FTHFS) structural gene sequences were recovered from roots of salt marsh plants, including Spartina alterniflora, Salicornia virginica, and Juncus roemerianus. Only S. alterniflora roots yielded sequences grouping with FTHFS sequences from known acetogens. Most other FTHFS or FTHFS-like sequences grouped with those from ...

Methanol is an important anaerobic substrate in industrial wastewater treatment and the natural environment. Previous studies indicate that cobalt greatly stimulates methane formation during anaerobic treatment of methanolic wastewaters. To evaluate the effect of cobalt in a mixed culture, a sludge with low background levels of cobalt was cultivated in an upflow anaerobic sludge blanket reactor. ...

Reductive acetogenesis via the acetyl coenzyme A (acetyl-CoA) pathway is an alternative hydrogen sink to methanogenesis in the rumen. Functional gene-based analysis is the ideal approach for investigating organisms capable of this metabolism (acetogens). However, existing tools targeting the formyltetrahydrofolate synthetase gene (fhs) are compromised by lack of specificity ...

Wittenberger, Charles L. (National Institute of Dental Research, U.S. Public Health Service, Bethesda, Md.), and Ann S. Haaf. Lactate-degrading system in Butyribacterium rettgeri subject to glucose repression. J. Bacteriol. 88:896�903. 1964.�The ability of Butyribacterium rettgeri to utilize lactate as the main energy source for growth requires the ...

SummaryThis paper describes the genome sequence of M. thermoacetica (f. Clostridium thermoaceticum), which is the model acetogenic bacterium that has been widely used for elucidating the Wood-Ljungdahl pathway of CO and CO₂ fixation. This pathway, which is also known as the reductive acetyl-CoA pathway, allows acetogenic (often ...

Methanol is an important anaerobic substrate in industrial wastewater treatment and the natural environment. Previous studies indicate that cobalt greatly stimulates methane formation during anaerobic treatment of methanolic wastewaters. To evaluate the effect of cobalt in a mixed culture, a sludge with low background levels of cobalt was cultivated in an upflow anaerobic sludge blanket reactor. ...

The microbial population structure and function of natural anaerobic communities maintained in lab-scale continuously stirred tank reactors at different lactate to sulfate ratios and in the absence of sulfate were analyzed using an integrated approach of molecular techniques and chemical analysis. The population structure, determined by denaturing gradient gel electrophoresis and by the use of ...

Changes in the acetogenic population were investigated in an experimental laboratory-scale biogas reactor (37�C) subjected to gradually elevated ammonia levels (0.8 to 6.9 g NH(4)(+)-N L(-1)). A shift from aceticlastic acetate degradation to syntrophic acetate oxidation had previously been confirmed in this reactor. In a parallel control reactor, operating at constant ...

Population development of key groups of bacteria involved in municipal refuse conversion to methane was measured from the time of initial incubation through the onset of methane production. Hemicellulolytic bacteria, cellulolytic bacteria, hydrogen-producing acetogens, and acetate-and H{sub 2}-plus-CO{sub 2}-utilizing methanogens were enumerated by the most-probable-number ...

The effects of co-cultivation with the hydrogen-utilizing acetogenic bacterium Acetitomaculum ruminis on the fermentative activities of the rumen fungi Neocallimastix patriciarum or Neocallimastix sp. L2 were investigated. In both co-cultures acetate production increased, making it the predominant fermentation product, as the accumulation of lactate, formate, ethanol, H2 and ...

Primers for PCR amplification of partial (1,102 of 1,680 bp) formyltetrahydrofolate synthetase (FTHFS) gene sequences were developed and tested. Partial FTHFS sequences were successfully amplified from DNA from pure cultures of known acetogens, from other FTHFS-producing organisms, from the roots of the smooth cordgrass, Spartina alterniflora, and from fresh horse manure. The ...

A variety of different media were used to isolate facultatively (FAB) and obligately anaerobic bacteria (OAB). These bacteria were isolated from core subsamples obtained from boreholes at the Idaho National Engineering Lab. (INEL) or at the Hanford Lab. (Yakima). Core material was sampled at various depths to 600 feet below the surface. All core samples with culturable bacteria contained at least ...

The aim of this work was to investigate in vitro interrelationships during xylan fermentation between an H2 and butyrate-producing xylanolytic species recently isolated in our laboratory from human faeces and identified as Roseburia intestinalis and the H2-utilizing acetogen Ruminococcus hydrogenotrophicus or the methanogen Methanobrevibacter smithii. H2 transfer between M. ...

Acetogenic bacteria grow by the oxidation of various substrates coupled to the reduction of carbon dioxide (acetogenesis) or other electron acceptors but the mechanisms of energy conservation are still enigmatic. Here, we report the presence of a rnf gene cluster rnfCDGEAB in Acetobacterium woodii that is speculated to encode a novel, energy-conserving ...

The biochemistry of acetogenesis is reviewed. The microbes that catalyze the reactions that are central to acetogenesis are described and the focus is on the enzymology of the process. These microbes play a key role in the global carbon cycle, producing over 10 trillion kilograms of acetic acid annually. Acetogens have the ability to anaerobically convert carbon dioxide and CO ...

A minimally defined medium was developed for the cultivation of the acetogen Clostridium thermoaceticum. The medium contained glucose as the carbon and energy source, ammonium sulfate as the nitrogen source, nicotinic acid as the sole essential vitamin, reductant, a phosphate-bicarbonate buffer, mineral salts and chelator, and a CO/sub 2/ gas phase. Adaptation of C. ...

Skatole (3-methylindole) is a malodorous chemical in stored swine manure and is implicated as a component of foul-tasting pork. Definitive evidence for the skatole pathway is lacking. Deuterium-labeled substrates were employed to resolve this pathway in the acetogenic bacterium Clostridium drakei and Clostridium scatologenes and to determine if a similar pathway is used by ...

The overall objective of the project is to develop two stage fermentation process for conversion of coal-derived synthesis gas to a mixture of alcohols. This is achieved in two steps. In the first step, B .methylotrophicum converts carbon monoxide (CO) to butyric and acetic acids. Subsequent fermentation of the acids by Clostridium acetobutylicum leads to the production of ...

An anaerobic, H2-utilizing bacterium, strain RD-1, was isolated from the highest growth-positive dilution series of a root homogenate prepared from the sea grass Halodule wrightii. Cells of RD-1 were gram-positive, spore-forming, motile rods that were linked by connecting filamen...

Objectives of this project dealt with understanding one- and multicarbon metabolism in acetogenic and methanogenic bacteria. The biochemistry of acetate catabolism in Methanosarcina barkeri in relation to their major enzyme activities, co-factors and inte...

The demethylation of the algal osmolyte dimethylsulfoniopropionate (DMSP) to methylthiopropionate (MTPA) by (homo)acetogenic bacteria was studied. Five Eubacterium limosum strains (including the type strain), Sporomusa ovata DSM 2662^T, Sporomusa sphaeroides DSM 2875^T, and Acetobacterium woodii DSM 1030^T were ...

Previous studies suggested that methanol and acetate were the likely methanogenic precursors in the cold Zoige wetland. In this study, the contribution of the two substances to methanogenesis and the conversion in Zoige wetland were analyzed. It was determined that methanol supported the highest CH(4) formation rate in the enrichments of the soil grown with Eleocharis valleculosa, and even higher ...

End product inhibition in methane on glucose and fatty acid substrates was studied in batch fermentations with enrichment cultures. Effects of pCO sub 2 and pCH sub 4 on kinetics and yields were determined. Propionate/butyrate oxidation by acetogens were ...

The acetogenic bacterium Clostridium thermoautotrophicum, grown on methanol, glucose, or CO2-H2, contained high levels of corrinoids, formate dehydrogenase, tetrahydrofolate enzymes, carbon monoxide dehydrogenase, and hydrogenase. Cell-free extracts catalyzed pyruvate-dependent formation of acetate from methyltetrahydrofolate. These results suggest that C. thermoautotrophicum ...

Clostridium carboxidivorans strain P7^T is a strictly anaerobic acetogenic bacterium that produces acetate, ethanol, butanol, and butyrate. The C. carboxidivorans genome contains all the genes for the carbonyl branch of the Wood-Ljungdahl pathway for CO₂ fixation, and it encodes enzymes for conversion of acetyl coenzyme A into ...

A long-chain fatty acid degrading (beta oxidizing), obligate proton-reducing, acetogenic bacterium strain SD2 of the genus Syntrophomonas has been isolated in coculture with a hydrogen-using bacterium, Desulfovibrio strain G-11. The enzymology of fatty ac...

to an S ) 3/2 form. Possible origins of this heterogeneity are discussed. Methanogenic archaea and acetogenic,10-phenanthroline; MES, 2-(N-morpholino)ethanesulfonic acid; thionin, 3,7-diaminophenothiazin-5-ium chloride; Etot

The effect of cultivation gas phase on the expression and activity of hydrogenase in heterotrophic cultures of Clostridium thermoaceticum was examined. Of the five gas phases tested, hydrogenase was maximal from cells cultivated under CO. Correlations were observed between the level of hydrogenase and the evolution of H/sub 2/ by growing cultures. Activity stains of polyacrylamide gels revealed a ...

Dichloromethane (DCM) is utilized by the strictly anaerobic, acetogenic mixed culture DM as a sole source of carbon and energy for growth. Growth with DCM was linear, and cell suspensions of the culture degraded DCM with a specific activity of 0.47 mkat/kg of protein. A mass balance of 2 mol of chloride and 0.42 mol of acetate per mol of DCM was observed. The dehalogenation ...

The objective of this study was to evaluate the role of reductive acetogenesis as an alternative H 2 disposal mechanism in the rumen. H 2/CO 2-supported acetogenic ruminal bacteria were enumerated by using a selective inhibitor of methanogenesis, 2-bromoethanesulfonic acid (BES). Acetogenic bacteria ranged in density from 2.5 ? 10 5 cells/ml in beef cows ...

Recent declines in sea grass distribution underscore the importance of understanding microbial community structure-function relationships in sea grass rhizospheres that might affect the viability of these plants. Phospholipid fatty acid analyses showed that sulfate-reducing bacteria and clostridia were enriched in sediments colonized by the sea grasses Halodule wrightii and Thalassia testudinum ...

Recent declines in sea grass distribution underscore the importance of understanding microbial community structure-function relationships in sea grass rhizospheres that might affect the viability of these plants. Phospholipid fatty acid analyses showed that sulfate-reducing bacteria and clostridia were enriched in sediments colonized by the sea grasses Halodule wrightii and Thalassia testudinum ...

Recent declines in sea grass distribution underscore the importance of understanding microbial community structure-function relationships in sea grass rhizosphere that might affect the viability of these plants. Phospholipid fatty acid analyses showed that sulfate-reducing bacter...

Population development of key groups of bacteria involved in municipal refuse conversion to methane was measured from the time of initial incubation through the onset of methane production. Hemicellulolytic bacteria, cellulolytic bacteria, hydrogen-producing acetogens, and acetate- and H(2)-plus-CO(2)-utilizing methanogens were enumerated by the most-probable-number technique ...

Population development of key groups of bacteria involved in municipal refuse conversion to methane was measured from the time of initial incubation through the onset of methane production. Hemicellulolytic bacteria, cellulolytic bacteria, hydrogen-producing acetogens, and acetate- and H₂-plus-CO₂-utilizing methanogens were ...

Sulfate-reducing bioreactors are a promising option for the treatment of acid mine drainage. We studied the structure and function of a biofilm in a methanol-fed fixed-bed in-lake reactor for the treatment of an acidic pit lake by a combination of laboratory incubations, chemical and molecular analyses and confocal laser scanning microscopy to determine whether competition by different groups of ...

A 750,000litre fermenter was studied throughout one entire year by investigating the concentrations of volatile fatty acids (acetic, butyric, i-butyric, propionic, valeric and i-valeric acids), pH, concentrations of total C, N, S and NH(4)(+)-N, amounts of chemical and biological oxygen demand, and abundance of acetogenic microorganisms. Additionally several process parameters ...

A variety of different media were used to isolate facultatively (FAB) and obligately anaerobic bacteria (OAB). These bacteria were isolated from core subsamples obtained from boreholes at the Idaho National Engineering Lab. (INEL) or at the Hanford Lab. (Yakima). Core material was sampled at various depths to 600 feet below the surface. All core samples with culturable bacteria contained at least ...

The biodegradation of lactose into methane was investigated in a chemostat ecosystem under steady state conditions in order to understand the intermediary metabolism and the responsible bacterial species; and, to model the anaerobic digestion of whey in a continuous contact process. Radioactive carbon tracer studies showed that lactose biomethanation occurred in three distinct but simultaneous ...

/sup 14/C-tracer techniques were used to examine the metabolism of methanol and methylamines and acetogenesis from hydrogen and carbon dioxide in sediments from the profundal and littoral zones of eutrophic Wintergreen Lake, Michigan. Methanogens were primarily responsible for the metabolism of methanol, mono-methylammine, and trimethylamine and maintained the pool size of these substrates below ...

After spiking anoxic sediment slurries of three acidic oligotrophic lakes with either HgCl₂ at 1.0 ?g/ml or CH₃HgI at 0.1 ?g/ml, both mercury methylation and demethylation rates were measured. High mercury methylation potentials were accompanied by high demethylation potentials in the same sediment. These high potentials correlated positively with the ...

The bacteria in the large intestines of 10 northern leopard frogs (Rana pipiens) were enumerated and partially characterized. Four nonhibernating frogs were collected in the summer, four hibernating frogs were collected in the winter, and two frogs just emerged from hibernation were collected in the spring. All frogs had about 10(10) bacteria per g (wet weight) of intestinal contents and about ...

Interspecies H2 transfer between two newly isolated fibrolytic strains (18P13 and 18P16) and H2-utilizing methanogen or acetogen from the human colon was investigated during in vitro cellulose degradation. Both H2-consuming microorganisms utilized efficiently H2 produced from cellulose fermentation by the fibrolytic species. H2 utilization by Methanobrevibacter smithii did not ...

Strain PA-1 (S. Barik, W.J. Brulla, and M.P. Bryant, Appl. Environ. Microbiol. 50:304-310, 1985) is an anaerobic, gram-negative rod that in pure culture decarboxylates succinate to propionate and that grows syntrophically as an acetogen with the H2 utilizer Methanospirillum hungatei if glucose, pyruvate, aspartate, or fumarate is provided. In pure culture, strain PA-1 grows ...

Fermenting microbial communities generate hydrogen; its removal through the production of acetate, methane, or hydrogen sulfide modulates the efficiency of energy extraction from available nutrients in many ecosystems. We noted that pathway components for acetogenesis are more abundantly and consistently represented in the gut microbiomes of monozygotic twins and their mothers than components for ...

Fermenting microbial communities generate hydrogen; its removal through the production of acetate, methane, or hydrogen sulfide modulates the efficiency of energy extraction from available nutrients in many ecosystems. We noted that pathway components for acetogenesis are more abundantly and consistently represented in the gut microbiomes of monozygotic twins and their mothers than components for ...

A mesophilic acetogenic bacterium (MPOB) oxidized propionate to acetate and CO₂ in cocultures with the formate- and hydrogen-utilizing methanogens Methanospirillum hungatei and Methanobacterium formicicum. Propionate oxidation did not occur in cocultures with two Methanobrevibacter strains, which grew only with hydrogen. Tricultures consisting of MPOB, ...

In abandoned coal mines, methanogenic archaea are responsible for the production of substantial amounts of methane. The present study aimed to directly unravel the active methanogens mediating methane release as well as active bacteria potentially involved in the trophic network. Therefore, the stable-isotope-labeled precursors of methane, [(13)C]acetate and H(2)-(13)CO(2), were fed to liquid ...

2,3-Butanediol (23BD) is a high-value chemical usually produced petrochemically but which can also be synthesized by some bacteria. To date, the best microbial 23BD production rates have been observed using pathogenic bacteria in fermentation systems that depend on sugars as the carbon and energy sources for product synthesis. Here we present evidence of 23BD production by three nonpathogenic ...

A thermophilic, fermentative microaerophile (ET-5b) and a thermophilic acetogen (ET-5a) were coisolated from oxic soil obtained from Egypt. The 16S rRNA gene sequence of ET-5a was 99.8% similar to that of the classic acetogen Moorella thermoacetica. Further analyses confirmed that ET-5a was a new strain of M. thermoacetica. For ET-5b, the nearest 16S rRNA ...

The possibility of providing the acetogenic microorganism Sporomusa ovata with electrons delivered directly to the cells with a graphite electrode for the reduction of carbon dioxide to organic compounds was investigated. Biofilms of S.�ovata growing on graphite cathode surfaces consumed electrons with the reduction of carbon dioxide to acetate and small amounts of ...

The acetogenic bacterium Clostridium thermoautotrophicum, grown on methanol, glucose, or CO/sub 2/-H/sub 2/, contained high levels of corrinoids, formate dehydrogenase, tetrahydrofolate enzymes, carbon monoxide dehydrogenase, and hydrogenase. Cell-free extracts catalyzed pyruvate-dependent formation of acetate form methyltetrahydrofolate. These results suggest that C. ...

The objective of this study was to evaluate the role of reductive acetogenesis as an alternative H₂ disposal mechanism in the rumen. H₂/CO₂-supported acetogenic ruminal bacteria were enumerated by using a selective inhibitor of methanogenesis, 2-bromoethanesulfonic acid (BES). Acetogenic ...

Frankly, I was surprised to receive an invitation to write a prefatory chapter for the Annual Review of Microbiology. I have read several such chapters written by outstanding researchers, many of whom I know and admire. I did not think I belonged to such a preeminent group. In my view, my contributions to the physiology and biochemistry of anaerobic thermophilic bacteria and, more lately, to ...

Volatile fatty acids (VFAs) are key intermediates in anaerobic digestion. Enriched acetogenic and methanogenic cultures were used for syntrophic anaerobic digestion of VFAs in a high-load continuous reactor fed with acetic (HAc), propionic (HPr) and butyric (HBu) acids at maximum concentrations of 5, 3 and 4 g/L, respectively. Interactive effects of HPr, HBu and HAc were ...

Acetogenic bacteria BP103 cells could be used as the absorbent for melanoidin pigment (MP) and molasses wastewater (MWW). The maximum MP adsorption yield of this strain observed from the dead (autoclaved) cell. It was two times higher than that with resting cells. However, the MP adsorption yield of the strain was 50-60% decreased by acclimatization with the media containing ...

Summary The termite gut spirochete, Treponema primitia, is a CO(2)-reductive acetogen that is phylogenetically distinct from other distantly related and more extensively studied acetogens such as Moorella thermoacetica. Research on T. primitia has revealed details about the role of spirochetes in CO(2)-reductive acetogenesis, a process important to the ...

The organization and species composition of bacterial trophic groups associated with lactose biomethanation were investigated in a whey-processing chemostat by enumeration, isolation, and general characterization studies. The bacteria were spatially organized as free-living forms and as self-immobilized forms appearing in flocs. Three dominant bacterial trophic group populations were present (in ...

Methanogenesis in wetlands is dependent on intermediary substrates derived from the degradation of biopolymers. Formate is one such substrate and is stimulatory to methanogenesis and acetogenesis in anoxic microcosms of soil from the fen Schl�ppnerbrunnen. Formate dissimilation also yields CO(2) as a potential secondary substrate. The objective of this study was to resolve potential differences ...

Acetate oxidation in Italian rice field at 50?�C is achieved by uncultured syntrophic acetate oxidizers. As these bacteria are closely related to acetogens, they may potentially also be able to synthesize acetate chemolithoautotrophically. Labeling studies using exogenous H(2) (80%) and (13)CO(2) (20%), indeed demonstrated production of acetate as almost exclusive primary ...

A thermophilic spore-forming bacterium (strain AMP) was isolated from a thermophilic methanogenic bioreactor that was fed with cobalt-deprived synthetic medium containing methanol as substrate. 16S rRNA gene analysis revealed that strain AMP was closely related to the acetogenic bacterium Moorella thermoacetica DSM 521(T) (98.3% sequence similarity). DNA-DNA hybridization ...

The overall objective of the project is to develop and optimize a two-stage fermentation process for the conversion of coal derived synthesis gas in an mixture of alcohols. The goals include the development of superior strains with high product tolerance and productivity, optimization of process conditions for high volumetric productivity and product concentrations, integration and optimization of ...

In environments where the amount of the inorganic electron acceptors (oxygen, nitrate, sulfate, sulfur oroxidized metal ions (Fe3+;Mn4+) is insufficient for complete breakdown of organic matter, methane is formed as the major reduced end product. In such methanogenic environments organic acids are degraded by syntrophic associations of fermenting, acetogenic bacteria (e.g., ...

A stable continuous method for producing ethanol from the anaerobic bacterial fermentation of a gaseous substrate containing at least one reducing gas involves culturing a fermentation bioreactor anaerobic, acetogenic bacteria in a liquid nutrient medium; supplying the gaseous substrate to the bioreactor; and manipulating the bacteria in the bioreactor by reducing the redox ...

The main objective in this research is to obtain basic information on the metabolism and physiology of the H/sub 2/-producing acetogenic bacteria. Syntrophomonas wolfei degrades butyrate, caproate and caprylate to acetate and H/sub 2/, valerate and heptanoate to acetate, propionate and H/sub 2/, and isoheptanoate to acetate, isovalerate and H/sub 2/. Since the degradation of ...

Newly designed primers for [Fe-Fe]-hydrogenases indicated that (i) fermenters, acetogens, and undefined species in a fen harbor hitherto unknown hydrogenases and (ii) Clostridium- and Thermosinus-related primary fermenters, as well as secondary fermenters related to sulfate or iron reducers might be responsible for hydrogen production in the fen. Comparative analysis of ...

The evolution of different feeding guilds in termites is paralleled by differences in the activity of their gut microbiota. In wood-feeding termites, carbon dioxide-reducing acetogenic bacteria were found to generally outprocess carbon dioxide-reducing methanogenic bacteria for reductant (presumably hydrogen) generated during microbial fermentation in the hindgut. By contrast, ...

A long-chain fatty acid degrading (beta oxidizing), obligate proton-reducing, acetogenic bacterium strain SD2 of the genus Syntrophomonas has been isolated in coculture with a hydrogen-using bacterium, Desulfovibrio strain G-11. The enzymology of fatty acid degradation is being studied to discover the differences of SD2 from S. wolfei which allow it to degrade long chain fatty ...

Five anaerobic bacteria were tested for their abilities to transform tetrachloromethane so that information about enzymes involved in reductive dehalogenations of polychloromethanes could be obtained. Cultures of the sulfate reducer Desulfobacterium autotrophicum transformed some 80 {mu}M tetrachloromethane to trichloromethane and a small amount of dichloromethane in 18 days under conditions of ...

In this 3-yr study, we investigated temporal and spatial changes in pools of pore-water methane, sulfate, and acetate (a methanogenic substrate), along with corresponding methane fluxes. Acetate accumulated to high concentrations (>500 {mu}M) in the shallow pore waters in winter and spring, indicating that acetogenic bacteria were metabolically active at 2-10{degree}C. High ...

Ni-dependent carbon monoxide dehydrogenases (Ni-CODHs) are a diverse family of enzymes that catalyze reversible CO:CO{sub 2} oxidoreductase activity in acetogens, methanogens, and some CO-using bacteria. Crystallography of Ni-CODHs from CO-using bacteria and acetogens has revealed the overall fold of the Ni-CODH core and has suggested structures for the C ...

Ni-dependent carbon monoxide dehydrogenases (Ni-CODHs) are a diverse family of enzymes that catalyze reversible CO:CO₂ oxidoreductase activity in acetogens, methanogens, and some CO-using bacteria. Crystallography of Ni-CODHs from CO-using bacteria and acetogens has revealed the overall fold of the Ni-CODH core and has suggested ...

Methane biogas production through anaerobic digestion (or biomethanation) is one of the few technologies that both produce bioenergy and protect the environment. When the focus of anaerobic digestion (AD) is shifted from primarily wastewater treatment to bioenergy production, efficiency and process stability become critical to the economic viability of AD technologies. Temperature-phased anaerobic ...

Syntrophococcus sucromutans is the predominant species capable of O demethylation of methoxylated lignin monoaromatic derivatives in the rumen. The enzymatic characterization of this acetogen indicated that it uses the acetyl coenzyme A (Woods) pathway. Cell extracts possess all the enzymes of the tetrahydrofolate pathway, as well as carbon monoxide dehydrogenase, at levels ...

Dissimilatory sulfate-reducing prokaryotes (SRB) are a very diverse group of anaerobic bacteria that are omnipresent in nature and play an imperative role in the global cycling of carbon and sulfur. In anoxic marine sediments sulfate reduction accounts for up to 50% of the entire organic mineralization in coastal and shelf ecosystems where sulfate diffuses several meters deep into the sediment. As ...

Dissimilatory sulfate-reducing prokaryotes (SRB) are a very diverse group of anaerobic bacteria that are omnipresent in nature and play an imperative role in the global cycling of carbon and sulfur. In anoxic marine sediments sulfate reduction accounts for up to 50% of the entire organic mineralization in coastal and shelf ecosystems where sulfate diffuses several meters deep into the sediment. As ...

The authors previously described a thermophilic (60/sup 0/C), syntrophic, two-membered culture which converted acetate to methane via a two-step mechanism in which acetate was oxidized to H/sub 2/ and CO/sub 2/. While the hydrogenotrophic methanogen Methanobacterium sp. strain THF in the biculture was readily isolated, we were unable to find a substrate that was suitable for isolation of the ...

Side-by-side experiments were conducted in a sulfate-reducing aquifer at a former fuel station to evaluate the effect of ethanol on biodegradation of other gasoline constituents. On one side, for approximately 9 months we injected groundwater amended with 1-3 mg/L benzene, toluene, and o-xylene (BToX). On the other side, we injected the same, adding approximately 500 mg/L ethanol. Initially the ...

Side-by-side experiments were conducted in an aquifer contaminated with methyl-tert-butyl ether (MTBE) at a former fuel station to evaluate the effect of ethanol release on the fate of pre-existing MTBE contamination. On one side, for approximately 9 months we injected groundwater amended with 1-3 mg/L benzene, toluene, and o-xylene (BToX). On the other side, we injected the same, adding ...

The bacterial Wood-Ljungdahl pathway for CO(2)-reductive acetogenesis is important for the nutritional mutualism occurring between wood-feeding insects and their hindgut microbiota. A key step in this pathway is the reduction of CO(2) to formate, catalysed by the enzyme formate dehydrogenase (FDH). Putative selenocysteine- (Sec) and cysteine- (Cys) containing paralogues of hydrogenase-linked FDH ...

The aim of this work was to determine whether reductive acetogenesis can provide an alternative to methanogenesis in the rumen. Gnotobiotic lambs were inoculated with a functional rumen microbiota lacking methanogens and reared to maturity on a fibrous diet. Lambs with a methanogen-free rumen grew well, and the feed intake and ruminal volatile fatty acid concentrations for lambs lacking ruminal ...

Methyl tert-butyl ether (MTBE) contamination is widespread in aquifers near urban areas around the world. Since this synthetic fuel oxygenate is resistant to most physical methods of treating fuel-contaminated water, biodegradation may be a useful means of remediation. Currently, information on anaerobic MTBE degradation is scarce. Depletion has been observed in soil and sediment microcosms from a ...

The anaerobic acetogenic bacterium Acetobacterium woodii couples caffeate reduction with electrons derived from hydrogen to the synthesis of ATP by a chemiosmotic mechanism with sodium ions as coupling ions, a process referred to as caffeate respiration. We addressed the nature of the hitherto unknown enzymatic activities involved in this process and their cellular ...

Among 170 strains of acetogenic bacteria, a strain No.BP103 showed the highest decolorization yield (76.4+/-3.2%) when cultivated at 30 degrees C for 5 days in molasses pigments medium containing glucose 3.0%, yeast extract 0.5%, KH2PO4 0.1% and MgSO4 x 7H2O 0.05% and the pH adjusted to 6.0. In addition this strain could decolorize 32.3+/-3.2% and 73.5+/-3.5% of molasses ...

A psychrotolerant, obligate anaerobic, acetogenic bacterium designated strain SyrA5 was isolated from black anoxic sediment of a brackish fjord. Cells were Gram-positive, non-sporeforming rods. The isolate utilized H(2)/CO(2), CO, fructose, glucose, ethanol, ethylene glycol, glycerol, pyruvate, lactate, betaine and the methyl-groups of several methoxylated benzoic derivatives ...

We examined the relative roles of acetogenic and sulfate-reducing bacteria in H₂ consumption in a previously characterized subsurface sandstone ecosystem. Enrichment cultures originally inoculated with ground sandstone material obtained from a Cretaceous formation in central New Mexico were grown with hydrogen in a mineral medium supplemented with 0.02% ...

Stable carbon isotope ratios (delta(13)C) were determined for alanine, proline, phenylalanine, valine, leucine, isoleucine, aspartate (aspartic acid and asparagine), glutamate (glutamic acid and glutamine), lysine, serine, glycine, and threonine from metabolically diverse microorganisms. The microorganisms examined included fermenting bacteria, organotrophic, chemolithotrophic, phototrophic, ...

Stable carbon isotope ratios (?13C) were determined for alanine, proline, phenylalanine, valine, leucine, isoleucine, aspartate (aspartic acid and asparagine), glutamate (glutamic acid and glutamine), lysine, serine, glycine, and threonine from metabolically diverse microorganisms. The microorganisms examined included fermenting bacteria, organotrophic, chemolithotrophic, phototrophic, ...

Hydrogenotrophic microbiota have a significant impact on colonic health; however, little is known about their diversity and ecology in situ. Here, molecular-based methods and multivariate analyses were used to examine the abundance and diversity of mucosa-associated hydrogenotrophic microbes in 90 biopsies collected from right colon, left colon and rectum of 25 healthy subjects. Functional genes ...

The anaerobic acetogenic bacterium Acetobacterium woodii couples the reduction of caffeate with electrons derived from hydrogen to the synthesis of ATP by a chemiosmotic mechanism using sodium ions as coupling ions, but the enzymes involved remain to be established. Previously, the electron transfer flavoproteins EtfA and EtfB were found to be involved in caffeate respiration. ...

The anaerobic acetogenic bacterium Acetobacterium woodii couples the reduction of caffeate with electrons derived from hydrogen to the synthesis of ATP by a chemiosmotic mechanism using sodium ions as coupling ions, but the enzymes involved remain to be established. Previously, the electron transfer flavoproteins EtfA and EtfB were found to be involved in caffeate respiration. ...

The effect of trace metal ions (Co�+, Cu�+, Fe�+, Mn�+, Mo?+, Ni�+, Zn�+, SeO?? and WO??) on growth and ethanol production by an ethanologenic acetogen, Clostridium ragsdalei was investigated in CO:CO?-grown cells. A standard acetogen medium (ATCC medium no. 1754) was manipulated by varying the concentrations of trace metals in the media. ...

The contents of several chemical elements were assessed in the haloalkaliphilic acetogenic bacterium Natroniella acetigena and the alkaliphilic sulfate-reducing bacterium Desulfonatronum lacustre using X-ray microanalysis, stereoscanning microscopy, and mass spectrometry. The organisms were found to differ significantly in their relative contents of S, K, P, and Cl. The P/S ...

The US Viking missions (1975-1976) failed to discover any biological activity on the surface of Mars. Yet, life may exist in the planet lithosphere which was found to contain a substantial amount of water. Martian interior can also provide microbial cryptolife with sources of carbon (CO, CO2, CH4) and energy (reduced elements and compounds, e.g. H2, CO, H2S, NH4+, CH4, Fe3+). Microorganisms ...

It was observed that during an organic load increase and a 2-fold hydraulic (and organic) load increase to 10-day daily HRT batch-fed anaerobic digesters, the free energy available for the anaerobic oxidation of higher molecular weight volatile fatty acids (VFAs) such as propionate, butyrate, and valerate stabilized at apparent steady-state minimum values. The concentration of these VFAs varied ...

This study describes brine lenses (cryopegs) found in Siberian permafrost derived from ancient marine sediment layers of the Arctic Ocean. The cryopegs were formed and isolated from sediment ~100,000-120,000 years ago. They remain liquid at the in situ temperature of -10�C as a result of their high salt content (170-300 g/L). [14C] Glucose is taken up by the cryopeg biomass at -15�C, ...

A two-column pilot scale downflow percolating fixed film (DPFF) anaerobic reactor treating deproteinized cheese whey (DPW) was used in this study. The system was operated at one-third of the maximum working volume in an attempt to avoid mass transfer limitations of the gas products (since two-thirds of the immobilized microbial culture was unsubmerged), as well as to minimize the effects of ...

Growth of Acetobacterium woodii on fructose was stimulated by Na+; this stimulation was paralleled by a shift of the acetate-fructose ratio from 2.1 to 2.7. Growth on H2-CO2 or on methanol plus CO2 was strictly dependent on the presence of sodium ions in the medium. Acetate formation from formaldehyde plus H2-CO by resting cells required Na+, but from methanol plus H2-CO did not. This is analogous ...

Great interest has emerged in biological CO?-fixing processes in the context of current climate change discussions. One example for such a process is the hydrogenotrophic production of acetic acid by anaerobic microorganisms. Acetogenic microorganisms make use of carbon dioxide in the presence of hydrogen to produce acetic acid and biomass. In order to establish a process for ...

Anaerobic bacteria were isolated from deep subsurface sediment samples taken at study sites in Idaho (INEL) and Washington (HR) by culturing on dilute and concentrated medium. Morphologically distinct colonies were purified, and their responses to 21 selected physiological tests were determined. Although the number of isolates was small (18 INEL, 27 HR) some general patterns could be determined. ...

An anaerobic baffled reactor with four compartments (C1-C4) was successfully used for treatment of acetone-butanol-ethanol fermentation wastewater and methane production. The chemical oxygen demand (COD) removal efficiency was 88.2% with a CH(4) yield of 0.25L/(g COD(removed)) when organic loading rate (OLR) was 5.4kg CODm(-3)d(-1). C1 played the most important role in solvents (acetone, butanol ...

A research team from the Gas Research Institute of Chicago have studied a method for producing cleaner and more concentrated methane gas from municipal wastes. To bring methane gas to pipeline quality can account for almost half the total cost of producing fuel from municipal wastes, so the cost benefits of the process were also considered. The process involves the almost total removal of CO/sub ...

The nickel- and iron-containing enzyme acetyl-CoA synthase (ACS) catalyzes de novo synthesis as well as overall cleavage of acetyl-CoA in acetogens, various other anaerobic bacteria, methanogens, and other archaea. The enzyme contains a unique active site metal cluster, designated the A cluster, that consists of a binuclear Ni-Ni center bridged to an [Fe(4)S(4)] cluster. In ...

The aim of this work is to characterize the capability of several clay materials as preservative of organic pollution for use as landfill barrier. Interaction of representative organic pollutants with different polarity and water solubility (atrazine, benzamide, methomyl, paraquat and toluene) with several clay materials coming from several locations of Spain were studied. Batch suspension method ...

We investigated the influence of the composition of the fibrolytic microbial community on the development and activities of hydrogen-utilizing microorganisms in the rumens of gnotobiotically reared lambs. Two groups of lambs were reared. The first group was inoculated with Fibrobacter succinogenes, a non-H₂-producing species, as the main cellulolytic organism, and the second ...

Anaerobic treatment of a volatile fatty acid (VFA) mixture was investigated under psychrophilic (3 to 8 C) conditions in two laboratory-scale expanded granular sludge bed reactor stages in series. The reactor system was seeded with mesophilic methanogenic granular sludge and fed with a mixture of VFAs. Good removal of fatty acids was achieved in the two-stage system. Relative high levels of ...

Anaerobic treatment of a volatile fatty acid (VFA) mixture was investigated under psychrophilic (3 to 8�C) conditions in two laboratory-scale expanded granular sludge bed reactor stages in series. The reactor system was seeded with mesophilic methanogenic granular sludge and fed with a mixture of VFAs. Good removal of fatty acids was achieved in the two-stage system. Relative high levels of ...

The potential for using readily available and cost-effective complex carbon sources, such as primary sludge (PS), for the bioremediation of sulfate-rich effluent streams, including acid mine drainage, has been constrained by the slow rate of solubilization and low yield of soluble products. Disposal of PS also remains a global problem. Recent studies of a patented recycling sludge bed reactor have ...

The nickel transport system of Clostridium thermoaceticum was investigated with {sup 63}NiCl{sub 2} and an anaerobic microfiltration transport assay. Transport was optimal at pH 7 to pH 7.5 and 65{degree}C and decreased in the presence of metabolic uncouplers and inhibitors. Exogenous nickel was concentrated 3,000-fold over the apparent nickel concentration gradient during typical transport ...

Acetate, propionate, and butyrate are intermediate products in the anaerobic bioconversion of organic matter to methane and carbon dioxide. This study examines the effects of acetate, propionate, and butyrate on the thermophilic oxidation of propionate in continuous-flow methanogenic sludge bed systems and in defined propionate-oxidizing cultures. Volatile fatty acids (VFA) in sludge inhibit ...

Evidence is provided that reductive acetogenesis can be stimulated in ruminal samples during short-term (24-h) incubations when methanogenesis is inhibited selectively. While addition of the reductive acetogen Peptostreptococcus productus ATCC 35244 alone had no significant influence on CH4 and volatile fatty acid (VFA) production in ruminal samples, the addition of this ...

Methanogenesis from the biomass in the anoxic biogas reactors is catalyzed by syntrophic cooperation between anaerobic bacteria, syntrophic acetogenic bacteria and methanogenic archaea. Understanding of microbial community composition within the biogas reactors may improve the methane production from biomass fermentation. In this study, methanogenic archaea diverity of a ...

ARCTECH has developed a novel process (MicGAS) for direct, anaerobic biomethanation of coals. Biomethanation potential of coals of different ranks (Anthracite, bitumious, sub-bitumious, and lignites of different types), by various microbial consortia, was investigated. Studies on biogasification of Texas Lignite (TxL) were conducted with a proprietary microbial consortium, Mic-1, isolated from ...

The purified nickel-containing CO dehydrogenase complex isolated from methanogenic Methanosarcina thermophila grown on acetate is able to catalyze the exchange of [1-14C] acetyl-coenzyme A (CoA) (carbonyl group) with 12CO as well as the exchange of [3'-32P]CoA with acetyl-CoA. Kinetic parameters for the carbonyl exchange have been determined: Km (acetyl-CoA) = 200 microM, Vmax = 15 min-1. CoA is a ...

The purified nickel-containing CO dehydrogenase complex isolated from methanogenic Methanosarcina thermophila grown on acetate is able to catalyze the exchange of [1-14C] acetyl-coenzyme A (CoA) (carbonyl group) with 12CO as well as the exchange of [3'-32P]CoA with acetyl-CoA. Kinetic parameters for the carbonyl exchange have been determined: Km (acetyl-CoA) = 200 microM, Vmax = 15 min-1. CoA is a ...

Carboxydothermus hydrogenoformans is a thermophilic strictly anaerobic bacterium that catalyses the water gas shift reaction, the conversion of carbon monoxide with water to molecular hydrogen and carbon dioxide. The thermodynamically favorable growth temperature, compared to existing industrial catalytic processes, makes this organism an interesting alternative for production of cheap hydrogen ...

Carboxydothermus hydrogenoformans is a thermophilic strictly anaerobic bacterium that catalyses the water gas shift reaction, the conversion of carbon monoxide with water to molecular hydrogen and carbon dioxide. The thermodynamically favorable growth temperature, compared to existing industrial catalytic processes, makes this organism an interesting alternative for production of cheap hydrogen ...

A thermophilic (60/sup 0/C), anaerobic coculture conspired of an acetate-oxidizing eubacterial rod (AOR) and a H/sub 2/-using methanogen, Methanobacterium sp. strain THF, was studied. The AOR was isolated from the coculture by dilution into medium, with ethylene glycol. It grew on ethylene glycol, 1,2 propanediol, formate, pyruvate, glycinebetaine, and H/sub 2/-CO/sub 2/, usually forming acetate ...

The aim of the work described here was to analyse the biomethanization process for three types of organic fraction of municipal solid waste (OFMSW) using two different inoculum sources in a sequential leach-bed anaerobic reactor under thermophilic (55 degrees C) and dry conditions (20%TS). The OFMSWs studied were: separately collected food waste (SC_OFMSW) from restaurants, synthetic waste ...

Oil field bacteria were characterized by cloning and sequencing of PCR-amplified 16S rRNA genes. A variety of gram-negative, sulfate-reducing bacteria was detected (16 members of the family Desulfovibrionaceae and 8 members of the family Desulfobacteriaceae). In contrast, a much more limited number of anaerobic, fermentative, or acetogenic bacteria was found (one Clostridium ...

Carbon monoxide-dependent production of H/sub 2/, CO/sub 2/, and CH/sub 4/ was detected in crude cell extracts of acetate-grown Methanosarcina barkeri. This metabolic transformation was associated with an active methyl viologen-linked CO dehydrogenase activity (5 to 10 U/mg of protein). Carbon monoxide dehydrogenase activity was inhibited 85% by 10 ..mu..M KCN and was rapidly inactivated by O/sub ...

Biomethanation is a process by which organic material is microbiologically converted under anaerobic conditions to biogas. Three main physiological groups of microorganisms are involved: fermenting bacteria, organic acid oxidizing bacteria, and methanogenic archaea. Microorganisms degrade organic matter via cascades of biochemical conversions to methane and carbon dioxide. Syntrophic relationships ...

The feasibility of sewage sludge co-digestion using intermediate waste generated inside a wastewater treatment plant, i.e. trapped grease waste from the dissolved air flotation unit, has been assessed in a continuous stirred lab reactor operating at 35�C with a hydraulic retention time of 20 days. Three different periods of co-digestion were carried out as the grease waste dose was increased. ...

The anaerobic bioconversion of raw and mechanically lysed waste-activated sludge was kinetically investigated. The hydrolysis of the biopolymers, such as protein, which leaked out from the biological sludge with ultrasonic lysis, was a first-order reaction in anaerobic digestion and the rate constant was much higher than the decay rate constant of the raw waste activated sludge. An anaerobic ...

Assay of O-demethylation in cell-free extracts of Acetobacterium woodii: we have shown that THF and ATP are necessary for enzyme activity and thus are probably reactants; apparent Km values were 0.65 mM for the methoxylated substrate, 0.27 mM for ATP, and 0.17 mM for DL-THF. The enzyme activity is present in the cytosol, rather than being membrane bound, and is sensitive to oxygen. There is ...

Although much newsprint is devoted to the subject of reducing the United States and other major developed countries dependence on their respective foreign energy sources; the most challenging issues for society is to provide long-term, sustainable energy sources to accommodate the global population as a whole. The projected population of planet Earth for the year 2050 is estimated to be in excess ...

The nickel-containing CO dehydrogenases from Acetobacterium woodii and Clostridium thermoaceticum were studied by EPR spectroscopy in order to define the components involved in the EPR spectrum obtained by reaction of the enzymes with the substrate, CO. Using isotopic substitution techniques, these experiments unequivocally establish that a nickel-carbon species is involved in the g = 2.08, 2.02 ...

The nickel-containing CO dehydrogenase from Acetobacterium woodii and Clostridium thermoaceticum were studied by EPR spectroscopy in order to define the components involved in the EPR spectrum obtained by reaction of the enzymes with the substrate, CO. Using isotopic substitution techniques, these experiments unequivocally establish that a nickel-carbon species is involved in the g=2.08, 2.02 EPR ...

In the laboratory our students were trained in modern techniques for the isolation and study of a wide variety of microbes from marine and brackish environments. Special emphasis was placed on anaerobes and archaebacteria. Microbial groups that were studied included the propionic bacteria, clostridia, methanogens, acetogens, hydrogen oxidizing anaerobes and aerobes, ...

A mesophilic bacterium, strain An4, was isolated from an underground gas storage reservoir with methanol as substrate and perchlorate as electron acceptor. Cells were Gram-negative, spore-forming, straight to curved rods, 0.5-0.8 microm in diameter, and 2-8 microm in length, growing as single cells or in pairs. The cells grew optimally at 37 degrees C, and the pH optimum was around 7. Strain An4 ...

A mesophilic bacterium, strain An4, was isolated from an underground gas storage reservoir with methanol as substrate and perchlorate as electron acceptor. Cells were Gram-negative, spore-forming, straight to curved rods, 0.5�0.8�?m in diameter, and 2�8�?m in length, growing as single cells or in pairs. The cells grew optimally at 37�C, and the pH optimum was around 7. Strain An4 ...

Hexachlorobenzene (HCB), pentachlorobenzene (QCB), all three isomers of tetrachlorobenzene (TeCB), 1,2,3-trichlorobenzene (1,2,3-TCB), and 1,2,4-TCB were reductively dechlorinated by enrichment cultures in the presence of lactate, glucose, ethanol, or isopropanol as the electron donor. The enrichment cultures originated from percolation columns filled with Rhine River sediment in which ...

Gut microbiota from Reticulitermes flavipes termites catalyzed an H₂-dependent total synthesis of acetate from CO₂. Rates of H₂-CO₂ acetogenesis in vitro were 1.11 � 0.37 ?mol of acetate g (fresh weight)^?1 h^?1 (equivalent to 4.44 � 1.47 nmol ...

According the NASA point of view, one way to have liquid water on Mars at shallow depths would be through subglacial volcanism. Such volcano-ice interactions could be going on beneath the polar caps of Mars today, or even within the adjacent permafrost around the margins of the ice caps. This is why one of the Earth's models, close to extraterrestrial environment, represented by active volcanoes ...

Population development of key groups of anaerobic and aerobic bacteria involved in municipal refuse decomposition under laboratory landfill bioreactors with and without leachate recycle and inoculation was measured since modeling municipal refuse was landfilled in bioreactors for about 210 days. Hydrolytic fermentative bacteria (HFB), hydrogen-producing acetogenic bacteria ...

This report summarizes the progress and research accomplishments of the DOE Anaerobic Digestion Program. The objective is to develop the technology base for anaerobic digestion of dedicated feedstocks to produce significant quantities of methane at a cost competitive with other gaseous fuels by 1995. During 1984 research was carried out under three tasks: pretreatment, biological processes, and ...

Microbiology, chemistry and dissolved gas in groundwater from Olkiluoto, Finland, were analysed over 3 years; samples came from 16 shallow observation tubes and boreholes from depths of 3.9-16.2 m and 14 deep boreholes from depths of 35-742 m. The average total number of cells (TNC) was 3.9 x 10(5) cells per ml in the shallow groundwater and 5.7 x 10(4) cells per ml in the deep groundwater. There ...

A multi-level sampler (MLS) was emplaced in a borehole straddling anaerobic, sulfate-rich Cretaceous-era shale and sandstone rock formations {approx}200 m below ground surface at Cerro Negro, New Mexico. Sterile quartzite sand contained in chambers in the sampler allowed in situ colonization and recovery of nucleic acids for molecular analyses. DGGE and 16S rRNA gene cloning results indicated a ...

The overall goal of this project is to understood how the carboxyl of acetate is formed by acetogenci bacteria. Our work involves a multidisciplinary approach toward understanding the details of this process which is a key step in the pathway by which anaerobic bacteria synthesize acetyl-CoA. We have used a number of techniques including spectroscopy, enzyme kinetics, electrochemistry, and ...

Cherry stillage is a high strength organic wastewater arising from the manufacture of alcoholic products by distillation of fermented cherries. It is made up of biorefractory polyphenols in addition to readily biodegradable organic matter. An anaerobic sequencing batch reactor (AnSBR) was used to treat cherry stillage at influent COD ranging from 5 to 50 g/L. Different cycle times were selected to ...

Moorella thermoacetica is an anaerobic acetogen, a class of bacteria that is found in the soil, the animal gastrointestinal tract, and the rumen. This organism engages the Wood-Ljungdahl pathway of anaerobic CO(2) fixation for heterotrophic or autotrophic growth. This paper describes a novel enzyme, oxalate oxidoreductase (OOR), that enables M. thermoacetica to grow on ...

The conversion routes of carbon monoxide (CO) at 55 degrees C by full-scale grown anaerobic sludges treating paper mill and distillery wastewater were elucidated. Inhibition experiments with 2-bromoethanesulfonate (BES) and vancomycin showed that CO conversion was performed by a hydrogenogenic population and that its products, i.e. hydrogen and CO2, were subsequently used by methanogens, ...

Microbial formate production and consumption during syntrophic conversion of ethanol or lactate to methane was examined in purified flocs and digestor contents obtained from a whey-processing digestor. Formate production by digestor contents or purified digestor flocs was dependent on CO₂ and either ethanol or lactate but not H₂ gas as an electron ...

A lab-scale expanded granular sludge bed (EGSB) reactor was seeded with granular sludge and operated to investigate the influence of temperature decrease on both process performance and the microbial community structure of the granular sludge. Synthetic wastewater containing sucrose and volatile fatty acids was used as feed. The EGSB reactor was brought online at a starting temperature of 15 ...