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characterization of three thermophilic strains of methanothrix ("methanosaeta") thermophila sp. nov. and rejection of methanothrix ("methanosaeta") thermoacetophila.three thermophilic methanothrix ("methanosaeta") strains, strains ptt (= dsm 6194t) (t = type strain), cals-1 (= dsm 3870), and z-517 (= dsm 4774), were characterized chemotaxonomically and compared with five mesophilic strains, methanothrix soehngenii ("methanosaeta concilii") gp6 (= dsm 3671), opfikon (= dsm 2139), fe (= dsm 3013), ua, and pm. these methanogens were exclusively acetotrophic and had a characteristic sheathed structure. the dna base compositions of the strains which we studied r ...19921380291
[observations of predominant methanogens on biomass from af, abr, and uasb reactors treating different wastewaters].the biomass taken from af, abr, and uasb digesters treating municipal wastewater, swine waste and molassese stillage wastewater, municipal and molassese stillage wastewater respectively, were observed by light, epifluorescence microscope and scanning electron microscope. the prevalent methanogens in these digesters were methanothrix. exception for abr carried out to treat swine waste, methanosarcina with three forms of aggregations, cysts, and granules were presented in other digesters. a sugges ...19892800545
early stages in biofilm development in methanogenic fluidized-bed reactors.biofilm development in methanogenic fluidized-bed reactors with sand as the carrier was studied on a laboratory scale. the microorganisms present in consecutive layers of the biofilm of mature sludge granules were preliminarily characterized on the basis of their morphology, element composition and adhesion capacity and were compared to bacteria which take part in the initial colonization of sand. the early phase of biofilm development was monitored with reactors receiving waste-waters containin ...19901366640
a fluoride-insensitive inorganic pyrophosphatase isolated from methanothrix soehngenii.an inorganic pyrophosphatase [e.c. 3.6.1.1] was isolated from methanothrix soehngenii. in three steps the enzyme was purified 400-fold to apparent homogeneity. the molecular mass estimated by gelfiltration was 139 +/- 7 kda. sodium dodecyl sulfate/polyacrylamide gel electrophoresis indicated that the enzyme is composed of subunits with molecular masses of 35 and 33 kda in an alpha 2 beta 2 oligomeric structure. the enzyme catalyzed the hydrolysis of inorganic pyrophosphate, tri- and tetrapolypho ...19921324658
methanogenic degradation of acetone by an enrichment culture.an anaerobic enrichment culture degraded 1 mol of acetone to 2 mol of methane and 1 mol of carbon dioxide. two microorganisms were involved in this process, a filament-forming rod similar to methanothrix sp. and an unknown rod with round to slightly pointed ends. both organisms formed aggregates up to 300 micron in diameter. no fluorescing bacteria were observed indicating that hydrogen or formate-utilizing methanogens are not involved in this process. acetate was utilized in this culture by the ...19873442449
[species composition of methane bacteria in fermented cattle manure].the species composition of methanogenic bacteria taking part in thermophilic and mesophilic methanogenesis of cattle manure was studied. in both cases methanogenic bacteria belonging to the genera methanosarcina, methanothrix, and methanobacterium were identified. the description of methanosarcina thermophila, methanosarcina mazei, methanothrix thermoacetophila and methanobacterium thermoformicicum are given. the methanogenic bacteria are able to utilize all the methane procursors known to date. ...19883186681
purification and characterization of an oxygen-stable carbon monoxide dehydrogenase of methanothrix soehngenii.carbon monoxide dehydrogenase was purified to apparent homogeneity from methanothrix soehngenii. in contrast with the carbon monoxide dehydrogenases from most other anaerobic bacteria, the purified enzyme of methanothrix soehngenii was remarkably stable towards oxygen and it was only slightly inhibited by cyanide. the native molecular mass of the carbon monoxide dehydrogenase of methanothrix soehngenii determined by gel filtration was 190 kda. the enzyme is composed of subunits with molecular ma ...19892714294
structures of minor ether lipids isolated from the aceticlastic methanogen, methanothrix concilii gp6.structures were determined for two phospholipids and three glycolipids purified from chloroform-methanol extracts of methanothrix concilii gp6. together they accounted for 14% of the total lipid and were based on a c20,20-diether core structure consisting of either 2,3-di-o-phytanyl-sn-glycerol or its 3'-hydroxy analog, namely, 2-o-[3,7,11,15-tetramethylhexadecyl]-3-o-[3'- hydroxy-3',7',11',15'-tetramethylhexadecyl]-sn-glycerol. these two core lipids formed phosphodiester bonds to ethanolamine a ...19892614262
nucleotide sequence of a 16s rrna encoding gene from the archaebacterium methanothrix soehngenii. 19892587263
isolation and characterization of acetyl-coenzyme a synthetase from methanothrix soehngenii.in methanothrix soehngenii, acetate is activated to acetyl-coenzyme a (acetyl-coa) by an acetyl-coa synthetase. cell extracts contained high activities of adenylate kinase and pyrophosphatase, but no activities of a pyrophosphate:amp and pyrophosphate:adp phosphotransferase, indicating that the activation of 1 acetate in methanothrix requires 2 atp. acetyl-coa synthetase was purified 22-fold in four steps to apparent homogeneity. the native molecular mass of the enzyme from m. soehngenii estimat ...19892571608
primary structure of the chromosomal proteins mc1a, mc1b, and mc1c from the archaebacterium methanothrix soehngenii.the chromosomal protein mc1 of methanothrix soehngenii is a family of three variants a, b, and c. these are small basic polypeptides of 89, 87, and 90 residues, respectively. their primary structures have been determined from automated sequence analyses of the intact proteins and from structural data provided by peptides derived from the variants by cleavage at aspartic acid, glutamic acid, arginine, and methionine residues. by comparison with variant b taken as reference, variants a and c prese ...19892507537
antigenic distinctiveness, heterogeneity, and relationships of methanothrix spp.a detailed immunologic analysis of methanothrix soehngenii opfikon (the type species of the genus), methanothrix sp. strain cals-1, and methanothrix concilii gp6 was performed. a variety of poly- and monoclonal antibody probes for a comprehensive panel of reference organisms were used to determine immunogenicity, antigenicity, and relationships. the three organisms are antigenically distinct but interrelated, forming an immunologically cohesive group, weakly related to methanosarcinae. a promine ...19872442138
layered structure of bacterial aggregates produced in an upflow anaerobic sludge bed and filter reactor.the ultrastructure of bacterial granules that were maintained in an upflow anaerobic sludge bed and filter reactor was examined. the reactor was fed a sucrose medium, and it was operated at 35 degrees c. scanning and transmission electron microscopy revealed that the granular aggregates were three-layered structures. the exterior layer of the granule contained a very heterogeneous population that included rods, cocci, and filaments of various sizes. the middle layer consisted of a slightly less ...19902383005
novel, acid-labile, hydroxydiether lipid cores in methanogenic bacteria.polar ether lipids extracted from 15 methanogenic bacteria, representative of seven genera, were screened by nuclear magnetic resonance and thin layer chromatography for the presence of hydroxyl groups on the c20-phytanyl moieties. major amounts of hydroxydiether core lipid were confirmed for methanosaeta concilii and discovered in two methanosarcina species, methanococcus voltae, and tentatively in several methanobacterium species. signals at 1.24 and 1.8-1.9 ppm in 1h nmr spectra are character ...19902380184
cloning, expression, and sequence analysis of the genes for carbon monoxide dehydrogenase of methanothrix soehngenii.the cdha and cdhb genes that code for the large and the small subunits of carbon monoxide dehydrogenase (cdh), respectively, were isolated from a genomic library of methanothrix soehngenii dna in escherichia coli, using polyclonal antibodies raised against purified cdh. after introduction in e. coli or desulfovibrio vulgaris, the cdh genes appeared to be expressed irrespective of their orientation, yielding immunoreactive proteins of 79 and 19 kda, corresponding in size to the known subunits of ...19911901858
hydroxyarchaetidylserine and hydroxyarchaetidyl-myo-inositol in methanosarcina barkeri: polar lipids with a new ether core portion.lipids of the methanogenic archaebacterium, methanosarcina barkeri were analyzed. the lipid content was 5.4% of dry cell and polar lipids comprised 87% of the total lipid. polar lipids were separated into 14 spots by two-dimensional thin-layer chromatography. these were six phospholipids, seven aminophospholipids and one glycolipid, of which two phospholipids and two aminophospholipids were major constituents. after removal of polar head groups from total lipids, two kinds of glycerol diether co ...19911901027
bacteriological composition and structure of granular sludge adapted to different substrates.the bacteriological composition and ultrastructure of mesophilic granular methanogenic sludge from a large-scale upflow anaerobic sludge blanket reactor treating wastewater from a sugar plant and of sludge granules adapted to ethanol and propionate were studied by counting different bacterial groups and by immunocytochemical methods. propionate-grown granular sludge consisted of two types of clusters, those of a rod-shaped bacterium immunologically related to methanothrix soehngenii and those co ...19911892385
paramagnetic centers and acetyl-coenzyme a/co exchange activity of carbon monoxide dehydrogenase from methanothrix soehngenii.carbon monoxide (co) dehydrogenase was purified, both aerobically and anaerobically, to apparent homogeneity from methanothrix soehngenii. the enzyme contained 18 +/- 2 (n = 6) mol fe/mol and 2.0 +/- 0.1 (n = 6) mol ni/mol. electron paramagnetic resonance (epr) spectra of the aerobically purified co dehydrogenase showed one sharp epr signal at g = 2.014 with several characteristics of a [3fe-4s]1+ cluster. the integrated intensity of this signal was low, 0.03 s = 1/2 spin/alpha beta dimer. the 3 ...19911847679
characterization of metabolic performance of methanogenic granules treating brewery wastewater: role of sulfate-reducing bacteria.granules from an upflow anaerobic sludge blanket system treating a brewery wastewater that contained mainly ethanol, propionate, and acetate as carbon sources and sulfate (0.6 to 1.0 mm) were characterized for their physical and chemical properties, metabolic performance on various substrates, and microbial composition. transmission electron microscopic examination showed that at least three types of microcolonies existed inside the granules. one type consisted of methanothrix-like rods with low ...19911785921
inhibition of pure cultures of methanogens by benzene ring compounds.the inhibition of methane production by methanosaeta concilii gp6, methanospirillum hungatei gp1, methanobacterium espanolae gp9, and methanobacterium bryantii m.o.h. during short-term (6-h) exposure to eight benzene ring compounds was studied. the concentration that caused 50% inhibition of the methane production rate (ic50) was dependent on the species and the toxicant. pentachlorophenol was the most toxic of the tested compounds, with an ic50 of less than 8 mg/liter for all species except m. ...19911746956
organization of a ribosomal rna gene cluster from the archaebacterium methanothrix soehngenii. 19901690876
cloning, sequence analysis, and functional expression of the acetyl coenzyme a synthetase gene from methanothrix soehngenii in escherichia coli.in the acetoclastic methanogen methanothrix soehngenii, acetate is activated to acetyl coenzyme a by acetyl coenzyme a synthetase (acs). the acs gene, coding for the single acs subunit, was isolated from a genomic library of m. soehngenii dna in escherichia coli by using antiserum raised against the purified acs. after introduction in e. coli, the acs gene was expressed, resulting in the production of an immunoreactive protein of 68 kda, which is approximately 5 kda smaller than the known size o ...19911680850
epr characterization of a high-spin system in carbon monoxide dehydrogenase from methanothrix soehngenii.carbon monoxide dehydrogenase and methyl-coenzyme m reductase were purified from 61ni-enriched and natural-abundance nickel-grown cells of the methanogenic archae methanothrix soehngenii. the nickel-epr signal from cofactor f-430 in methyl-com reductase was of substoichiometric intensity and exhibited near-axial symmetry with g = 2.153, 2.221 and resolved porphinoid nitrogen superhyperfine splittings of approximately 1 mt. in the spectrum from 61ni-enriched enzyme a well-resolved parallel i = 3/ ...19911662611
genetic and physiological characterization of the rhodospirillum rubrum carbon monoxide dehydrogenase system.a 3.7-kb dna region encoding part of the rhodospirillum rubrum co oxidation (coo) system was identified by using oligonucleotide probes. sequence analysis of the cloned region indicated four complete or partial open reading frames (orfs) with acceptable codon usage. the complete orfs, the 573-bp coof and the 1,920-bp coos, encode an fe/s protein and the ni-containing carbon monoxide dehydrogenase (codh), respectively. the four 4-cysteine motifs encoded by coof are typical of a class of proteins ...19921644755
comparison of acetate utilization among strains of an aceticlastic methanogen, methanothrix soehngenii.the kinetics of acetate utilization by concentrated suspensions of cells was examined in five strains of methanothrix soehngenii. the rate of acetate utilization by all strains was dependent on the initial acetate concentration and followed simple michaelis-menten kinetics. the ability to utilize acetate differed among the various strains of m. soehngenii and was highest in the strain designated mtas.19921610192
a contrary view of the proposal to assign a neotype strain for methanothrix soehngenii. 19921581194
formation of unilamellar liposomes from total polar lipid extracts of methanogens.unilamellar liposomes were formed by controlled detergent dialysis of mixed micelles consisting of acetone-insoluble total polar lipids extracted from various methanogens and the detergent n-octyl-beta-d-glucopyranoside. the final liposome populations were studied by dynamic light scattering and electron microscopy. unilamellar liposomes with mean diameters smaller than 100 nm were obtained with lipid extracts of methanococcus voltae, methanosarcina mazei, methanosaeta concilii, and methanococcu ...19921444403
quantification of methanogenic groups in anaerobic biological reactors by oligonucleotide probe hybridization.the microbial community structure of anaerobic biological reactors was evaluated by using oligonucleotide probes complementary to conserved tracts of the 16s rrnas of phylogenetically defined groups of methanogens. phylogenetically defined groups of methanogens were quantified and visualized, respectively, by hybridization of 32p- and fluorescent-dye-labeled probes to the 16s rrnas from samples taken from laboratory acetate-fed chemostats, laboratory municipal solid waste digestors, and full-sca ...19947517129
simultaneous removal of phenol, ortho- and para-cresol by mixed anaerobic consortia.two different anerobic consortia, one removing phenol and ortho (o-) cresol and other removing para(p-) cresol, were cultivated in serum bottles using whey as cosubstrate substitute for proteose peptone. phenol and p-cresol removal with the phenol-removing consortium were the same with 0.0125% (w/v) whey as with 0.05% proteose peptone. for the other consortium, 8 days were required to decrease the p-cresol concentration from 35 to 2 mg/l with 0.025% whey, while 35 days were required to achieve a ...199910490333
methanogenesis in thermophilic biogas reactors.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 ...19957741531
cloning, characterization, and functional expression of acs, the gene which encodes acetyl coenzyme a synthetase in escherichia coli.acetyl coenzyme a synthetase (acs) activates acetate to acetyl coenzyme a through an acetyladenylate intermediate; two other enzymes, acetate kinase (ack) and phosphotransacetylase (pta), activate acetate through an acetyl phosphate intermediate. we subcloned acs, the escherichia coli open reading frame purported to encode acs (f. r. blattner, v. burland, g. plunkett iii, h. j. sofia, and d. l. daniels, nucleic acids res. 21:5408-5417, 1993). we constructed a mutant allele, delta acs::km, with t ...19957751300
fermentative degradation of acetone by an enrichment culture in membrane-separated culture devices and in cell suspensions.a mixed culture, woact, growing on acetone, consisted of two dominant morphotypes: a rod-shaped acetone-fermenting bacterium producing acetate, and an acetate-utilizing methanosaeta species. dense cell suspensions, largely free of the aceticlastic methanogen and supplemented with bromoethanesulfonate, were able to degrade acetone and grow in small volumes in membrane-separated culture devices in which the acetate produced could diffuse into a large volume of medium. acetone degradation and growt ...19947958774
[methane fermentation of cattle manure at low temperature].the acclimated microbial association fermenting cattle manure at 6 degrees c with methane production was obtained by a long-time (2.5 years) autoselection. it is shown that the basic barrier to carry out this process at low temperature is long-time period of adaptation of microbial community. it is removed by addition of the psychrophilic barm obtained. after cultivating of this psychrophilic methanogenic association under mesophilic (35 degrees) and thermophilic (55 degrees) conditions its acti ...19938277910
effect of medium composition and sludge removal on the production, composition, and architecture of thermophilic (55 degrees c) acetate-utilizing granules from an upflow anaerobic sludge blanket reactor.a thermophilic upflow anaerobic sludge blanket (uasb) reactor degrading acetate was started by applying published methods (w. m. wiegant and a. w. a. de man, biotechnol. bioeng. 28:718-77, 1986) for production of granules dominated by methanothrix spp. the reactor was inoculated with thermophilic digested sludge. no granules were observed during the first 7 months of start-up of the uasb reactor. however, after the concentrations of potassium, phosphate, ammonium, and magnesium in the medium wer ...19938368841
membrane atpase from the aceticlastic methanogen methanothrix thermophila.a new isolate of the aceticlastic methanogen methanothrix thermophila utilizes only acetate as the sole carbon and energy source for methanogenesis (y. kamagata and e. mikami, int. j. syst. bacteriol. 41:191-196, 1991). atpase activity in its membrane was found, and atp hydrolysis activity in the ph range of 5.5 to 8.0 in the presence of mg2+ was observed. it had maximum activity at around 70 degrees c and was specifically stimulated up to sixfold by 50 mm nahso3. the proton atpase inhibitor n,n ...19938416913
freeze-fracture planes of methanogen membranes correlate with the content of tetraether lipids.methanospirillum hungatei gp1 contained 50% of its ether core lipids (polar lipids less head groups) as tetraether lipids, and its plasma membrane failed to fracture along its hydrophobic domain during freeze-etching. the membrane of methanosaeta ("methanothrix") concilii did not contain tetraether lipids and easily fractured to reveal typical intramembranous particles. methanococcus jannaschii grown at 50 degrees c contained 20% tetraether core lipids, which increased to 45% when cells were gro ...19938432712
detection and localization of syntrophic propionate-oxidizing bacteria in granular sludge by in situ hybridization using 16s rrna-based oligonucleotide probes.in situ hybridization with fluorescent oligonucleotides was used to detect and localize microorganisms in the granules of two lab-scale upflow anaerobic sludge blanket reactors that had been fed for several months with either sucrose or a mixture of volatile fatty acids. sections of the granules were hybridized with 16s rrna-targeted oligonucleotide probes for bacteria, archaea, specific phylogenetic groups of methanogens, and two syntrophic propionate-oxidizing strains, mpob and koprop1. cells ...19968633864
microbial populations associated with treatment of an industrial dye effluent in an anaerobic baffled reactor.fluorescent in situ hybridization (fish) using 16s and 23s rrna-targeted probes together with construction of an archaeal 16s ribosomal dna (rdna) clone library was used to characterize the microbial populations of an anaerobic baffled reactor successfully treating industrial dye waste. wastewater produced during the manufacture of food dyes containing several different azo and other dye compounds was decolorized and degraded under sulfidogenic and methanogenic conditions. use of molecular metho ...200111425746
methanogenesis from acetate by cell-free extracts of the thermophilic acetotrophic methanogen methanothrix thermophila cals-1high rates of methanogenesis from acetate and atp were observed from cell-free extracts of the thermophilic acetotrophic methanogen methanothrix (methanosaeta) thermophila strain cals-1 when cultures were grown in a ph auxostat fed with acetic acid. specific methanogenic activities ranged from 50-300 nmol min-1 (mg protein)-1, which was comparable to those for whole cells. in contrast to results with methanosarcina spp., the reaction did not require high levels of h2 in the headspace. co was inh ...19968824151
development of methanogenic consortia in fluidized-bed batches using sepiolite of different particle size.the addition of support materials, such as sepiolite, to fluidized-bed anaerobic digesters enhances the methane production by increasing the colonization by syntrophic microbiota. however, the efficiency in the methanogenesis depends on the particle size of the support material, the highest level of methane production being obtained by the smaller particle size sepiolite. because of the porosity and physico-chemical characteristics of these support materials, the anaerobic microbial consortia fo ...19968897423
functional patterns and temperature response of cellulose-fermenting microbial cultures containing different methanogenic communities.the effect of microbial composition on the methanogenic degradation of cellulose was studied using two lines of anaerobic cellulose-fermenting methanogenic microbial cultures at two different temperatures: that at 15 degrees c being dominated by methanosaeta and that at 30 degrees c by methanosarcina. in both cultures, ch4 production and acetate consumption were completely inhibited by either 2-bromoethanesulfonate or chloroform, whereas h2 consumption was only inhibited by chloroform, suggestin ...200111499933
analysis of the co dehydrogenase/acetyl-coenzyme a synthase operon of methanosarcina thermophila.the cdhabc genes encoding the respective alpha, epsilon, and beta subunits of the five-subunit (alpha, beta, gamma, delta, and epsilon) co dehydrogenase/acetyl-coenzyme synthase (codh/acs) complex from methanosarcina thermophila were cloned and sequenced. northern (rna) blot analyses indicated that the cdh genes encoding the five subunits and an open reading frame (orf1) with unknown function are cotranscribed during growth on acetate. northern blot and primer extension analyses suggested that m ...19968955306
diversity and structure of the methanogenic community in anoxic rice paddy soil microcosms as examined by cultivation and direct 16s rrna gene sequence retrieval.a dual approach consisting of cultivation and molecular retrieval of partial archaeal 16s rrna genes was carried out to characterize the diversity and structure of the methanogenic community inhabiting the anoxic bulk soil of flooded rice microcosms. the molecular approach identified four groups of known methanogens. three environmental sequences clustered with methanobacterium bryantii and methanobacterium formicicum, six were closely related but not identical to those of strains of methanosaet ...19989501436
kinetics of acetate oxidation by two sulfate reducers isolated from anaerobic granular sludgekinetic parameters of acetate oxidation were determined for the sulfate reducers desulforhabdus amnigenus and desulfobacca acetoxidans. based on these parameters, both sulfate reducers seem to be able to outcompete methanosaeta spp. for acetate in acetate-fed anaerobic bioreactors. mixed-substrate studies showed that d. amnigenus degraded acetate and hydrogen simultaneously but preferred lactate, propionate, and ethanol over acetate.19989603856
interspecific, intraspecific and interoperonic variability in the 16s rrna gene of methanogens revealed by length and single-strand conformation polymorphism analysis.thirty-seven strains of mesophilic and thermophilic methanogenic archaea, belonging to 30 species, were analyzed by length polymorphism (lp) and single-strand conformation polymorphism (sscp) of an amplified 300-bp fragment of the 16s rrna gene (escherichia coli positions 9-331) including the variable regions v1 and v2, lps and sscps were detected between species and between strains of the same species (methanobacterium formicicum). lps were found in mb. formicicum dsmz 3637, mb. ivanovii dsmz 2 ...19989682489
microbial diversity in a hydrocarbon- and chlorinated-solvent-contaminated aquifer undergoing intrinsic bioremediation.a culture-independent molecular phylogenetic approach was used to survey constituents of microbial communities associated with an aquifer contaminated with hydrocarbons (mainly jet fuel) and chlorinated solvents undergoing intrinsic bioremediation. samples were obtained from three redox zones: methanogenic, methanogenic-sulfate reducing, and iron or sulfate reducing. small-subunit rrna genes were amplified directly from aquifer material dna by pcr with universally conserved or bacteria- or archa ...19989758812
investigation of serine hydroxymethyltransferase in methanogens.the cofactor specificity of serine hydroxymethyltransferase (shmt) activities was tested in extracts of several methanogens using tetrahydromethanopterin (h4mpt) from methanobacterium thermoautotrophicum marburg, tetrahydrosarcinapterin (h4spt) from methanosarcina barkeri, and tetrahydrofolate (h4folate) as the potential c1 carrier. in methanosphaera stadtmanae and methanococcus thermolithotrophicus, the activities were h4mpt dependent. in methanospirillum hungatei gp1, methanosaeta concilii, me ...19989783425
immobilization patterns and dynamics of acetate-utilizing methanogens immobilized in sterile granular sludge in upflow anaerobic sludge blanket reactors.sterile granular sludge was inoculated with either methanosarcina mazeii s-6, methanosaeta concilii gp-6, or both species in acetate-fed upflow anaerobic sludge blanket (uasb) reactors to investigate the immobilization patterns and dynamics of aceticlastic methanogens in granular sludge. after several months of reactor operation, the methanogens were immobilized, either separately or together. the fastest immobilization was observed in the reactor containing m. mazeii s-6. the highest effluent c ...199910049862
fluorescence in situ hybridization using 16s rrna-targeted oligonucleotides reveals localization of methanogens and selected uncultured bacteria in mesophilic and thermophilic sludge granules.16s rrna-targeted in situ hybridization combined with confocal laser scanning microscopy was used to elucidate the spatial distribution of microbes within two types of methanogenic granular sludge, mesophilic (35 degrees c) and thermophilic (55 degrees c), in upflow anaerobic sludge blanket reactors fed with sucrose-, acetate-, and propionate-based artificial wastewater. the spatial organization of the microbes was visualized in thin sections of the granules by using fluorescent oligonucleotide ...199910049894
methanogenic population dynamics during start-up of anaerobic digesters treating municipal solid waste and biosolids.an aggressive start-up strategy was used to initiate codigestion in two anaerobic, continuously mixed bench-top reactors at mesophilic (37 degrees c) and thermophilic (55 degrees c) conditions. the digesters were inoculated with mesophilic anaerobic sewage sludge and cattle manure and were fed a mixture of simulated municipal solid waste and biosolids in proportions that reflect u.s. production rates. the design organic loading rate was 3.1 kg volatile solids/m3/day and the retention time was 20 ...199810099211
high purity 14ch4 generation using the thermophilic acetotrophic methanogen methanothrix sp. strain cals-1.methane-oxidizing activity in natural samples is typically measured by amending 14ch4 to the sample and then following the accumulation of 14co2. current biological techniques to synthesize 14ch4 yield significant quantities of 14co that when oxidized to 14co2 would artificially inflate the measured methane-oxidizing activity of a sample. we present here a new method to biologically produce highly-pure 14ch4 using methanothrix sp. strain cals-1 which produces very little co. using this method, 1 ...199910192047
acetate and co2 assimilation by methanothrix concilii.biosynthetic pathways in methanothrix concilii, a recently isolated aceticlastic methanogen, were studied by 13c-nuclear magnetic resonance spectroscopy. labeling patterns of amino acids, lipids, and carbohydrates were determined. similar to other methanogens, acetate was carboxylated to pyruvate, which was further converted to amino acids by various biosynthetic pathways. the origin of carbon atoms in glutamate, proline, and arginine clearly showed that an incomplete tricarboxylic acid cycle op ...19853922956
hydrogen-using bacteria in a methanogenic acetate enrichment culture.in a study of the anaerobic utilization of acetate, an enrichment culture of sewage sludge organisms was initiated with calcium acetate as the sole carbon and energy source. a mixed bacterial population became established from which 14 anaerobic species were isolated. two of the isolates were methanogenic bacteria but only one of these, methanosarcina barkeri, utilised acetate as an energy source in axenic culture. the other methanogenic isolate, a methanobacterium sp., utilised h2/co2 but not a ...19846423605
molecular characterization of a toluene-degrading methanogenic consortium.a toluene-degrading methanogenic consortium enriched from creosote-contaminated aquifer material was maintained on toluene as the sole carbon and energy source for 10 years. the species in the consortium were characterized by using a molecular approach. total genomic dna was isolated, and 16s rrna genes were amplified by using pcr performed with kingdom-specific primers that were specific for 16s rrna genes from either members of the kingdom bacteria or members of the kingdom archaea. a total of ...199910584020
anaerobic digestion from residue of industrial cassava industrialization with acidogenic and methanogenic physical separation phases.a trial was carried out in a continuous regimen, using a completely stirred tank reactor, at acidogenic phase, and a hybrid reactor (upflow anaerobic sludge blanket + fixed bed) at methanogenic phase at room temperature. the residue to be treated came from a flour and cassava meal industry, and the reactors operated for 300 d with affluent chemical oxygen demand (cod) concentrations of 7500, 9000, 11,000, and 14,000 mg/l. the final results showed a biogas production with a content of 80% methane ...200010849839
flexible community structure correlates with stable community function in methanogenic bioreactor communities perturbed by glucose.methanogenic bioreactor communities were used as model ecosystems to evaluate the relationship between functional stability and community structure. replicated methanogenic bioreactor communities with two different community structures were established. the effect of a substrate loading shock on population dynamics in each microbial community was examined by using morphological analysis, small-subunit (ssu) rrna oligonucleotide probes, amplified ribosomal dna (rdna) restriction analysis (ardra), ...200010966429
single strand conformation polymorphism monitoring of 16s rdna archaea during start-up of an anaerobic digester.a laboratory-scale continuously mixed anaerobic digester was inoculated with a mix of anaerobic sludge and fed with glucose. the start-up strategy was progressive and chemical analyses were done to evaluate digester performance from day 1 to day 107. in parallel, archaeal community dynamics were monitored by sscp analysis of the v3 region of 16s rdna genes and further characterized by partial sequencing of 16s rdna genes. at day 1 the inoculum contained at least five distinct archaeal peaks clos ...200111137601
characterization of microbial consortia in a terephthalate-degrading anaerobic granular sludge system.the microbial composition and spatial distribution in a terephthalate-degrading anaerobic granular sludge system were characterized using molecular techniques. 16s rdna clone library and sequence analysis revealed that 78.5% of 106 bacterial clones belonged to the delta subclass of the class proteobacteria; the remaining clones were assigned to the green non-sulfur bacteria (7.5%), synergistes (0.9%) and unidentified divisions (13.1%). most of the bacterial clones in the delta-proteobacteria for ...200111158354
hydrogen production by methanogens under low-hydrogen conditions.hydrogen production was studied in four species of methanogens (methanothermobacter marburgensis, methanosaeta thermophila, methanosarcina barkeri, and methanosaeta concilii) under conditions of low (sub-nanomolar) ambient hydrogen concentration using a specially designed culture apparatus. transient hydrogen production was observed and quantified for each species studied. methane was excluded as the electron source, as was all organic material added during growth of the cultures (acetate, yeast ...200011195097
anaerobic codigestion of municipal solid waste and biosolids under various mixing conditions--ii: microbial population dynamics.microbial population dynamics were evaluated in anaerobic codigesters treating municipal solid waste and sewage sludge. ribosomal rna based oligonucleotide probes were used to characterize changes in population abundance of syntrophic volatile fatty acid degrading bacteria and methanogens. changes in community structure were linked to traditional performance parameters during the recovery of previously unstable codigesters induced by a reduction in mixing levels. methanosarcina spp. were the mos ...200111329684
study of microbial community of brewery-treating granular sludge by denaturing gradient gel electrophoresis of 16s rrna gene.the microbial community structure of granular sludge from an upflow anaerobic sludge blanket (uasb) reactor treating brewery effluent was studied by denaturing gradient gel electrophoresis (dgge). twelve major bands were observed in the dgge fingerprint for the bacteria domain and four bands for the archaea domain. of the bacterial bands observed, six were successfully purified and sequenced. among them, three were related to the gram-positive low g + c group, one to the delta subclass of the pr ...200111379115
functional and structural response of a cellulose-degrading methanogenic microbial community to multiple aeration stress at two different temperatures.two cellulose-fermenting methanogenic enrichment cultures originating from rice soil, one at 15 degrees c with methanosaeta and the other at 30 degrees c with methanosarcina as the dominant acetoclastic methanogen, both degraded cellulose anaerobically via propionate, acetate and h2 to ch4. the degradation was a two-stage process, with ch4 production mainly from h2/co2 and accumulation of acetate and propionate during the first, and methanogenic consumption of acetate during the second stage. ae ...200111472500
cluster structure of anaerobic aggregates of an expanded granular sludge bed reactor.the metabolic properties and ultrastructure of mesophilic aggregates from a full-scale expanded granular sludge bed reactor treating brewery wastewater are described. the aggregates had a very high methanogenic activity on acetate (17.19 mmol of ch(4)/g of volatile suspended solids [vss].day or 1.1 g of ch(4) chemical oxygen demand/g of vss.day). fluorescent in situ hybridization using 16s rrna probes of crushed granules showed that 70 and 30% of the cells belonged to the archaebacterial and eub ...200111472948
[the granulation of pcp-degrading anaerobic sludge with industrial organic wastewater as co-substrate].the granulation of pcp degrading anaerobic sludge in two improved uasb reactors under co-existence of two types of industrial wastewater and pcp were studied. it was found that the granulation of pcp degrading anaerobic sludge could be divided into three stages, i.e. sludge acclimation, granular pre-formation and granular maturation. the changes in biomass, sludge bioactivity, population and ecological distribution of three group bacteria involved in anaerobic digestion during the course of gran ...200111507893
[characteristics of granular sludge during start-up of the internal circulation].the quick start-up of the laboratory scale ic reactor and the characteristics of granular sludge during start-up were studied in this paper. the results showed that the first start-up of ic reactor could be finished in 20 days, while secondary start-up only needed 15 days with cod loading rate of 12-15 kg.(m3.d)-1 and cod removal larger than 85%. during start-up, the characteristics of granular sludge changed greatly: average granular diameter was increased from 0.88 mm to 1.25 mm; average settl ...200111507902
performance of uasb reactor treating leachate from acidogenic fermenter in the two-phase anaerobic digestion of food waste.this study was conducted to investigate the performance of the upflow anaerobic sludge blanket (uasb) reactor treating leachate from acidogenic fermenter in the two-phase anaerobic digestion of food waste. the chemical oxygen demand (cod) removal efficiency was consistently over 96% up to the loading rates of 15.8 g cod/l d. the methane production rate increased to 5.51/l d. of all the cod removed, 92% was converted to methane and the remaining presumably to biomass. at loading rates over 18.7 g ...200111547866
phenol degradation in horizontal-flow anaerobic immobilized biomass (haib) reactor under mesophilic conditions.a bench-scale horizontal-flow anaerobic immobilized biomass (haib) reactor was assayed aiming to verify its potential use for phenol degradation. the haib reactor consisted of a bore-silicate tube (100 cm long; 5.04 cm diameter) filled with polyurethane foam matrices containing immobilized anaerobic sludge. before being subjected to phenol, the reactor was fed with synthetic substrate at the influent chemical oxygen demand (cod) of 1,028 mg.l-1 achieving 98% of cod removal efficiency. thereafter ...200111575081
influence of porosity and composition of supports on the methanogenic biofilm characteristics developed in a fixed bed anaerobic reactor.this paper reports on the influence of the material porosity on the anaerobic biomass adhesion on four different inert matrices: polyurethane foam, pvc, refractory brick and special ceramic. the biofilm development was performed in a fixed-bed anaerobic reactor containing all the support materials and fed with a synthetic wastewater containing protein, lipids and carbohydrates. the data obtained from microscopic analysis and kinetic assays indicated that the material porosity has a crucial impor ...200111575085
bacteria and archaea physically associated with gulf of mexico gas hydrates.although there is significant interest in the potential interactions of microbes with gas hydrate, no direct physical association between them has been demonstrated. we examined several intact samples of naturally occurring gas hydrate from the gulf of mexico for evidence of microbes. all samples were collected from anaerobic hemipelagic mud within the gas hydrate stability zone, at water depths in the ca. 540- to 2,000-m range. the delta(13)c of hydrate-bound methane varied from -45.1 per thous ...200111679338
the effect of polymer addition on granulation in an anaerobic baffled reactor (abr). part ii: compartmentalization of bacterial populations.the microbial ecology of wastewater treatment plants remains one of the least understood aspects in both aerobic and anaerobic systems, despite the fact that both processes are ultimately dependent on an active biomass for operational efficiency. ultimately, future developments in anaerobic treatment processes will require a much greater understanding of the fundamental relationships between bacterial populations within the biomass if optimum process efficiency is to be fully realised. this stud ...200211848365
effects of amendment with ferrihydrite and gypsum on the structure and activity of methanogenic populations in rice field soil.methane emission from paddy fields may be reduced by the addition of electron acceptors to stimulate microbial populations competitive to methanogens. we have studied the effects of ferrihydrite and gypsum (caso(4). 2h(2)o) amendment on methanogenesis and population dynamics of methanogens after flooding of italian rice field soil slurries. changes in methanogen community structure were followed by archaeal small subunit (ssu) ribosomal dna (rdna)- and rrna-based terminal restriction fragment le ...200211976125
isolation and characterization of acetate-utilizing anaerobes from a freshwater sediment.acetate-degrading anaerobic microorganisms in freshwater sediment were quantified by the most probable number technique. from the highest dilutions a methanogenic, a sulfate-reducing, and a nitrate-reducing microorganism were isolated with acetate as substrate. the methanogen (culture ampb-zg) was non-motile and rod-shaped with blunted ends (0.5-1 mm x 3-4 mm long). doubling times with acetate at 30-35 degrees c were 5.6-8.1 days. the methanogen grew only on acetate. analysis of the 16s rrna seq ...200012035087
quantification of methanosaeta species in anaerobic bioreactors using genus- and species-specific hybridization probes.a bstractto evaluate the role of methanosaeta spp. in a variety of anaerobic environments, small-subunit rrna targeted oligonucleotide hybridization probes were developed and experimentally characterized. the probes were designed to be genus specific for methanosaeta and species specific for methanosaeta concilii and methanosaeta thermophila. the temperature of dissociation was determined for each probe. probe specificities were determined using a diverse collection of archaea and through an eva ...200012035101
enrichment of thermophilic syntrophic anaerobic glutamate-degrading consortia using a dialysis membrane reactor.a dialysis cultivation system was used to enrich slow-growing moderately thermophilic anaerobic bacteria at high cell densities. bicarbonate buffered mineral salts medium with 5 mm glutamate as the sole carbon and energy source was used and the incubation temperature was 55 degrees c. the reactor inoculum originated from anaerobic methanogenic granular sludge bed reactors. the microbial population was monitored over a period of 2 years using the most probable number (mpn) technique. in the react ...200212037615
differentiation of methanosaeta concilii and methanosarcina barkeri in anaerobic mesophilic granular sludge by fluorescent in situ hybridization and confocal scanning laser microscopyoligonucleotide probes, designed from genes coding for 16s rrna, were developed to differentiate methanosaeta concilii, methanosarcina barkeri, and mesophilic methanogens. all m. concilii oligonucleotide probes (designated ms1, ms2, and ms5) hybridized specifically with the target dna, but ms5 was the most specific m. concilii oligonucleotide probe. methanosarcina barkeri oligonucleotide probes (designated mb1, mb3, and mb4) hybridized with different methanosarcina species. the mb4 probe specifi ...199910224023
vertical distribution of methanogens in the anoxic sediment of rotsee (switzerland).anoxic sediments from rotsee (switzerland) were analyzed for the presence and diversity of methanogens by using molecular tools and for methanogenic activity by using radiotracer techniques, in addition to the measurement of chemical profiles. after pcr-assisted sequence retrieval of the 16s rrna genes (16s rdna) from the anoxic sediment of rotsee, cloning, and sequencing, a phylogenetic analysis identified two clusters of sequences and four separated clones. the sequences in cluster 1 grouped w ...199910347020
characterization of microbial community in granular sludge treating brewery wastewater.the diversity and distribution of microbes within brewery-degrading anaerobic sludge granules were studied using various molecular techniques. molecular cloning of small-subunit rrna gene sequences indicated that all archaeal clones were affiliated with methanosaeta concillii (>99% sequence similarity), and the bacterial clones were mostly affiliated with a not-yet-cultured clostridium cluster (48 out of 99 clones) in the low g + c gram-positive group, xanthomonas spp. in the gamma-subclass of p ...200212044076
diversity, abundance, and activity of archaeal populations in oil-contaminated groundwater accumulated at the bottom of an underground crude oil storage cavity.fluorescence in situ hybridization has shown that cells labeled with an archaea-specific probe (arch915) accounted for approximately 10% of the total cell count in oil-contaminated groundwater accumulated at the bottom of an underground crude oil storage cavity. although chemical analyses have revealed vigorous consumption of nitrate in cavity groundwater, the present study found that the methane production rate was higher than the nitrate consumption rate. to characterize the likely archaeal po ...200212147488
evaluation of thermophilic anaerobic microbial consortia using fluorescence in situ hybridization (fish).in this study we investigated the development of anaerobic biofilms in differential reactors and suspension cultures in batch reactors under thermophilic (55 degrees c) conditions. fish, sem, chemical and chromatographic analysis were used. the differential reactors reached 99.6%, 92.3% and 6.7% of acetic acid, cod and sulfate removal efficiencies, respectively, after 166 h of incubation time. the batch reactor reached 95.6% and 31.8% of acetic acid and sulfate removal efficiencies after 675 h, ...200212188557
biofilm development in down flow anaerobic fluidised bed reactors under transient conditions.biofilm development onto polypropylene particles (<4 mm) was studied in a laboratory-scale down flow anaerobic fluidised bed reactor. the reactor was fed with a synthetic solution containing sucrose and nutrients, and operated at 35 degrees c during 65 days at 44% bed expansion rate and 36 h hrt. scanning electron microscopy (sem) monitored the biofilm development. initial adhesion occurred within the first 6 hours and after day 44 biofilm structure was complete. the presence of attached cells m ...200212216632
microbial community structure in a thermophilic anaerobic hybrid reactor degrading terephthalate.a thermophilic terephthalate-degrading methanogenic consortium was successfully enriched for 272 days in an anaerobic hybrid reactor, and the microbial structure was characterized using terminal rflps, clone libraries and fluorescence in-situ hybridization with rrna-targeted oligonucleotide probes. all the results suggested that methanothrix thermophila-related methanogens, desulfotomaculum-related bacterial populations in the gram-positive low-g + c group, and op5-related populations were the k ...200415470120
diversity and structure of the archaeal community in the leachate of a full-scale recirculating landfill as examined by direct 16s rrna gene sequence retrieval.the diversity and structure of the archaeal community in the effluent leachate from a full-scale recirculating landfill was characterized by direct 16s rrna gene (16s rdna) retrieval. total-community dna was extracted from the microbial assemblages in the landfill leachate, and archaeal 16s rdnas were amplified with a universally conserved primer and an archaea-specific primer. the amplification product was then used to construct a 16s rdna clone library, and 70 randomly selected archaeal clones ...200212351237
methanogenic population dynamics during startup of a full-scale anaerobic sequencing batch reactor treating swine waste.changes in methanogenic population levels were followed during startup of a full-scale, farm-based anaerobic sequencing batch reactor (asbr) and these changes were linked to operational and performance data. the asbr was inoculated with anaerobic digester sludge from a municipal wastewater treatment facility. during an acclimation period of approximately 3 months, the asbr content was diluted to maintain a total ammonia-n level of approximately 2000mg l(-1). after this acclimation period, the vo ...200212418668
selective enrichment and purification of cultures of methanosaeta spp.a simple method for the isolation of axenic cultures of members of the obligately acetotrophic methanogenic genus methanosaeta is described. to overcome the competitive advantage obtained by faster growing acetate-utilizing methanosarcina spp. in batch enrichment cultures, acetone and isopropanol are used as the growth substrates for the enrichment step. acetone- and isopropanol-utilizing bacteria slowly ferment these substrates to acetate, which allows methanosaeta spp. to maintain the acetate ...200312459244
microbial community structure and activity in a compartmentalized, anaerobic bioreactor.the objective of this study was to evaluate staging and its effects on reactor performance in a compartmentalized bioreactor, designated the anaerobic migrating blanket reactor (ambr). the ambr was operated by reversing the flow several times per day, which allowed for substantial biomass migration without biomass accumulation in the final compartment. during reactor startup, the structures of the microbial communities in the five compartments were quite similar despite substantial differences i ...200212469949
methanogenic population structure in a variety of anaerobic bioreactors.the methanogenic community structures of six anaerobic sludges were examined using culture-independent techniques. the sludges were obtained from full-scale and laboratory-scale bioreactors, treating a variety of low- and high-strength, simple and complex wastewaters at psychrophilic (10-14 degrees c), mesophilic (37 degrees c) and thermophilic (55 degrees c) temperatures. amplified rdna restriction analysis identified 18 methanogenic operational taxonomic units in the six samples. 16s rrna gene ...200312620635
phylogenetic analysis of bacterial populations in an anaerobic microbial consortium capable of degrading saturation concentrations of tetrachloroethylene.an anaerobic microbial consortium able to biodegrade saturation levels of perchloroethylene (pce) in a column containing a source zone of pce was examined phylogenetically to determine microbial community structure and spatial variation in relation to the pce source. the consortium was comprised of at least 34 members with 7 organisms sharing affiliations with known respiratory or cometabolic dechlorinators. seven other organisms had their closest phylogenetic relative detected in other environm ...200312674344
quantification and diversity of the archaeal community in a landfill site.at a sea-based, solid waste disposal site, methanogenic organisms were quantified by molecular approaches. the samples collected for analysis were from anaerobic leachate of the landfill site. when the dna extracted from the leachate was examined by a quantitative pcr method using domain-specific 16s rdna primers, archaeal dna represented 2-3% of the total extracted dna. on the basis of cloning and sequence comparison of the archaeal pcr products, more than half of the sequences belonged to eury ...200312674345
analysis of the sulfate-reducing bacterial and methanogenic archaeal populations in contrasting antarctic sediments.the distribution and activity of communities of sulfate-reducing bacteria (srb) and methanogenic archaea in two contrasting antarctic sediments were investigated. methanogenesis dominated in freshwater lake heywood, while sulfate reduction dominated in marine shallow bay. slurry experiments indicated that 90% of the methanogenesis in lake heywood was acetoclastic. this finding was supported by the limited diversity of clones detected in a lake heywood archaeal clone library, in which most clones ...200312788715
methanogen population in a marine biofilm corrosive to mild steel.this study was conducted to analyze the methanogen population in a corrosive marine biofilm based on 16s rdna analysis, using a pcr-cloning-sequencing approach. there were 80 methanogen clones developed from the pcr-amplified dna extracted from the biofilm on the mild steel surface. all clones were categorized into one of five operational taxonomy units (otus). two otus (comprising 57 clones) were affiliated with the acetotrophic methanosaeta genus; the remaining three otus (23 clones) were affi ...200312879307
investigation of variations in microbial diversity in anaerobic reactors treating landfill leachate.a young landfill leachate containing elevated total ammonia concentrations frequently as high as 2,700 mg/l was anaerobically treated for 1,015 days in two different laboratory-scale anaerobic reactors configured as sludge blanket and hybrid bed. in this paper, the last 265 days of this long-term anaerobic treatability study are presented. effects of high ammonia concentrations on reactor performances were correlated to the variations in microbial diversity by identifying the dominant microorgan ...200314531428
population dynamics of rumen microbes using modern techniques in rumen enhanced solid incubation.the microbial ecology of the rumen is very complex. different species of bacteria, protozoa, and fungi are involved in digestion of plant material in ruminants. in spite of complicated interrelationships among the various groups of microorganisms in the rumen ecosystem, bacteria and archaea are believed to play a major role because of their numerical predominance and metabolic diversity. in this work we are presenting the results for microbial population dynamics of rumen microbes during two-sta ...200314531429
molecular ecology of anaerobic granular sludge grown at different conditions.qualitative and quantitative diversity of microorganisms present in anaerobic granular sludges fed with different substrates, as well as the structure of these granules have been studied using fluorescent 16s rrna-targeted in situ hybridization and electron microscopy. the granules showed a multi-layered structure, in which both densely packed and loose micro-colonies, channels and holes could be observed. only bacteria were found in the outer shell of the granules, while both archaea and bacter ...200314640200
microbial community evaluation of anaerobic granular sludge from a hybrid reactor treating pentachlorophenol by using fluorescence in situ hybridization.we used in situ hybridization with fluorescently labeled rrna-targeted oligonucleotide probes concurrently with microscopic examinations and methane measurements to characterize the microbial community of an anaerobic hybrid reactor treating pentachlorophenol (pcp) with a mixture of fatty acids (propionic, butyric, acetic and lactic) and methanol. archaeal cells detected with probe arc915 prevailed in anaerobic granular sludge without and with the addition of pcp in a range of 2.0 to 21.0 mg/l t ...200314640201
characterization of methanogenic and methanotrophic assemblages in landfill samples.a greater understanding of the tightly linked trophic groups of anaerobic and aerobic bacteria residing in municipal solid waste landfills will increase our ability to control methane emissions and pollutant fate in these environments. to this end, we characterized the composition of methanogenic and methanotrophic bacteria in samples taken from two regions of a municipal solid waste landfill that varied in age. a method combining polymerase chain reaction amplification, restriction fragment len ...200314667383
long-term effects of operating temperature and sulphate addition on the methanogenic community structure of anaerobic hybrid reactors.the diversity, population dynamics, and activity profiles of methanogens in anaerobic granular sludges from two anaerobic hybrid reactors treating a molasses wastewater both mesophilically (37 degrees c) and thermophilically (55 degrees c) during a 1081 day trial were determined. the influent to one of the reactors was supplemented with sulphate, after an acclimation period of 112 days, to determine the effect of competition with sulphate-reducing bacteria on the methanogenic community structure ...200414723931
formation of granules and methanosaeta fibres in an anaerobic migrating blanket reactor (ambr).it has generally been accepted that the formation of granules in anaerobic wastewater treatment systems requires a hydraulic upflow pattern. to evaluate this hypothesis, we operated an anaerobic migrating blanket reactor (ambr) without a hydraulic upflow pattern, using a synthetic wastewater containing acetate, propionate, butyrate and sucrose. we provided conditions amenable to the formation of granules by operating the system with a moderate hydraulic selection pressure, which in this system w ...200415008810
anaerobic sludge granulation.this paper reviews different theories on anaerobic sludge granulation in uasb-reactors that have been proposed during the past two decades. the initial stages of the formation of anaerobic granules follow the same principles as biofilm formation of bacteria on solid surfaces. there exist strong evidence that inert carriers play an important positive role in granulation. most researchers conclude that methanosaeta concilii is a key organism in granulation. only the cape town hypothesis presumes t ...200415016515
syntrophic-methanogenic associations along a nutrient gradient in the florida everglades.nutrient runoff from the everglades agricultural area resulted in a well-documented gradient of phosphorus concentrations in soil and water, with concomitant ecosystem-level changes, in the northern florida everglades. it was recently reported that sulfate-reducing prokaryote assemblage composition, numbers, and activities are dependent on position along the gradient (h. castro, k. r. reddy, and a. ogram, appl. environ. microbiol. 68:6129-6137, 2002). the present study utilized a combination of ...200415184146
effect of dilution rate on metabolic pathway shift between aceticlastic and nonaceticlastic methanogenesis in chemostat cultivation.acetate conversion pathways of methanogenic consortia in acetate-fed chemostats at dilution rates of 0.025 and 0.6 day(-1) were investigated by using (13)c-labeled acetates, followed by gas chromatography-mass spectrometry (gc-ms) analysis of the ch(4) and co(2) produced. nonaceticlastic syntrophic oxidation by acetate-oxidizing syntrophs and hydrogenotrophic methanogens was suggested to occupy a primary pathway (approximately 62 to 90%) in total methanogenesis at the low dilution rate. in contr ...200415240282
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